Modern Loveok

CHAPTER 1 INTRODUCTION1.1 History of Refrigerator SystemHuman being are looking for ways to keep their food fresh, and found out that the coldness satisfy it. Therefore the idea of refrigeration was born. For centuries people relay on ice and snow for the purpose of cooling things. Since the Roman Empire, slaves used terracotta pots fanning in water to cool down the food.

That is the method of cooling by extracting heat. Until 1844, Jacob Perkins, an American inventor acquired the pattern of the first evaporative cooling refrigerator and a new chapter of refrigeration has begun. After the invention of the first refrigerator, people started to gain more and more interest in using man made machines rather than natural ice for cooling food. The early refrigerator models in the nineteenth century made the foundation of the more functional and more stylized refrigerators in the future.

Many kinds of refrigerator exist in our society today, each with its own distinct function. But the refrigerator in our home is the most commonly seen and utilized. It serves primary function to keep our food fresh. This study discuss specifically on home refrigerator.

Like the air conditioner, it is also consist of the following four basic components: 1.Evaporator 2.Compressor 3.Condenser 4.

Expansion device. 7Fig 1.1: Schematic diagram of a refrigeration system1.2 Basic of Refrigeration System Refrigerator is a cooling appliance comprising a thermally insulated compartment and a refrigeration system is a system to produce cooling effect in the insulated compartment. Meanwhile, refrigeration is define as a process of removing heat from a space or substance and transfers that heat to another space or substance. Nowadays, refrigerators are extensively used to store foods which deteriorate at ambient temperatures; spoilage from bacterial growth and other processes is much slower in refrigerator that has low temperatures. In refrigeration process, the working fluid employed as the heat absorber or cooling agent is called refrigerant. The refrigerant absorbs heat by evaporating at low temperature and pressure and remove heat by condensing at a higher temperature and pressure.

As the heat is removed from the refrigerated space, the area appears to become cooler. A vapor compression cycle is used in most household refrigerators, refrigerator–freezers and freezers. In this cycle, a circulating refrigerant such as R134a enters a compressor as low-pressure vapor at or slightly above the temperature of the refrigerator interior.

The vapor is compressed and exits the compressor as high-pressure superheated vapor. The superheated vapor travels under pressure through coils or tubes comprising “the condenser”, which are passively cooled by exposure to air in the room. The condenser cools the vapor, which liquefies. As the refrigerant leaves the condenser, it is still under pressure but is now only slightly above room temperature. This liquid refrigerant is forced through a metering or throttling device, also known as an expansion valve (essentially a pin-hole sized constriction in the tubing) to an area of much lower pressure. Thesudden decrease in pressure results in explosive-like flash evaporation of a portion (typically about half) of the liquid. The latent heat absorbed by this flash evaporation is drawn mostly from adjacent still-liquid refrigerant, a phenomenon known as “auto-refrigeration”.

This cold and partially vaporized refrigerant continues through the coils or tubes of the evaporator unit. A fan blows air from the refrigerator or freezer compartment (“box air”) across these coils or tubes and the refrigerant completely vaporizes, drawing further latent heat from the box air. This cooled air is returned to the refrigerator or freezer compartment, and so keeps the box air cold.

Note that the cool air in the refrigerator or freezer is still warmer than the refrigerant in the evaporator. Refrigerant leaves the evaporator, now fully vaporized and slightly heated, and returns to the compressor inlet to continue the cycle. 1,2,3…10Main Component of refrigerator:1 Compressor2 Condenser3 Expansion (capillary)4 EvaporatorFig1.2: Schematic diagram of a refrigeration system1.2.

1 Main function of each component of refrigeration systema. Compressor: The low pressure and temperature vapour refrigerant from evaporator is drawn into the compressor through the inlet or suction valve A, where it is compressed to a high pressure and temperature. This high pressure and temperature vapour refrigerant is discharged into the condenser through the delivery or discharge valve B. b. Condenser: The condenser or cooler consists of coils of pipe in which the high pressure and temperature vapour refrigerant is cooled and condensed. The refrigerant, while passing through the condenser, gives up its latent heat to the surrounding condensing medium which is normally air or water. c.

Receiver: The condensed liquid refrigerant from the condenser is stored in a vessel known as receiver from where it is supplied to the evaporator through the expansion valve or refrigerant control valve. It is used for the constant supply of refrigerant to the evaporator.d. Expansion Valve: It is also called throttle valve or refrigerant control valve. The function of the expansion valve is to allow the liquid refrigerant under high pressure and temperature to pass at a controlled rate after reducing its pressure and temperature. Some of the liquid refrigerant evaporates as it passes through the expansion valve, but the greater portion is vaporized in the evaporator at the low pressure and temperature. e.

Evaporator: An evaporator consists of coils of pipe in which the liquid-vapour. Refrigerant at low pressure and temperature is evaporated and changed into vapour refrigerant at low pressure and temperature. In evaporating, the liquid vapour refrigerant absorbs its latent heat of vaporization from the medium (air, water or brine) which is to be cooled. Fig 1.3: Actual working diagram of a refrigeration systemProcesses Involved in Vapor Compression Refrigeration System:Fig1.4:T-S Diagram for the Ideal Vapor Compression Refrigeration CycleFig 1.

5 : Pressure-enthalpy graph for vapour compression refrigeration systemProcess 1 – 2: Isentropic compression in compressor. Process 2 –3: Constant pressure heat rejection in condenser. Process 3 – 4: Isenthalpic expansion in expansion device.

Process 4 –1: Constant pressure heat absorption in evaporator.1.3 Advantages of Vapour Compression Cycle: C.O.P. is quite high as the working of the cycle is very near to that of reversed Carnot cycle. When used on ground level the running cost of vapour compression refrigeration system is only 1/5 of air refrigeration system. .

i.e. it has low running cost. For the same refrigeration effect the size of the plant is smaller. The required temperature of the evaporator can be achieved simply by adjusting the control valve of the same unit.1.

4 Factors Affcting The Performance Of VC Refrigration SystemFrom the literature survey it is observed that following factors affect the performance of vapour compression refrigeration system. Properties of working fluid. Mixture proportions of different refrigerants. Suction pressure. Discharge pressure.

Pressure ratio. Amount of charge filled. Dimensions of capillary tubes 1.5 Refrigerant1.5.1 What is RefrigerantThe working fluid used to transfer the heat from low temperature reservoir to high temperature reservoir is called refrigerant.

Different Types of Refrigerant1 Halocarbon compound: They are molecules composed of carbon, chlorine and fluorine. They are stable, allowing them to reach the stratosphere without too many problems. It contributes to the destruction of the ozone layer. Some important halocarbon are: R11,R12,R13,R21,R22,R40,R100,R113,R114,R1522 Azeotropes: This group of refrigerant consists of mixture of different refrigerant which cannot be separated under pressure and temperature and they have fixed thermodynamic properties.e.

g.R500 is the mixture 7308% of R1226.2% of R152.3 Hydrocarbons (HC):This is primarily propane (R290), butane (R600) and isobutene (R600a). These fluids have good thermodynamic properties, but are dangerous because of their flammability. The world of the cold has always been wary of these fluids, even if they have reappeared recently in refrigerators and insulating foams. Their future use in air conditioning seems unlikely, given the cost of setting both mechanical and electrical safety.4 Inorganic compounds: Before the development of hydrocarbon group refrigerants, these were used in past commonly used refrigerants of his group are:R717-Ammonia(NH3),R718-Wter(H2O),R729-Air,R744,(CO2),R764-Sulphur dioxide(SO2)5 Unsaturated organic compounds: This group of refrigerants is hydrocarbon with ethylene and propylene base.

Example is: R1120-Trichloroehylene (C2HCL3), R1130 Dichlroehylene (C2H2CL2), R1150-Ethylene (C2H4), R1270-Propylene (C3H6), R1270-Propylene (C3H6). 10,12 1.5.2 CFC REFRIGERANTSSince the 1930s, chlorofluorocarbons (CFCs) have been widely used as foam blowing agents, aerosols and especially refrigerants due to their pre-eminent properties such as stability, non-toxicity, non-flammability and thermodynamic properties. In particular, R12 has been predominantly used for small refrigeration units including domestic refrigerator/freezers.

Refrigerant R12 has been the most dominant refrigerant for refrigeration industry. However, they also have harmful effect on the earth’s protective ozone layer 1. So, they are being regulated internationally by Montreal Protocol since 1989 2. Later, it was also proved that CFCs also contributed significantly to the global warming problem. The global warming potential of R12 is considered to be 8500 times that of CO2 over 100 years 3. Greenhouse gas emissions led to the Kyoto Protocol in 1997. It was thus decided that by 2010 4, producing and using of CFCs should be prohibited completely all over the world. In consequence, a lot of research has been done to find the suitable eco-friendly replacement of CFCs.

1.5.3 HCFC Refrigerant The initial alternatives included some hydro chlorofluorocarbons, or HCFCs, but they are likely to be phased out internationally around 2040, because their ozone depletion potentials and global warming potentials are in relative high levels though less than those of CFCs 5. By that time compounds such as HFCs (hydro fluorocarbons), which are benign to the ozone layer, are likely to have replaced HCFCs. As a result, it has become an urgent issue to search and develop CFC and HCFC alternatives. While the presence of single component refrigerants reduces the performance possibilities, the solution appears to lie in using the synthetic mixtures. The search for alternate refrigerants as substitutes for R134a in various refrigeration systems has been an important area of research in the RAC sector. As per the Montreal Protocol, developed countries have already phased out R12 and developing countries like India have to do the same before the end of 2010.

None of the alternative refrigerants can be used in the R12 based appliances without making system modifications or technology change 6. In developing countries the growth of RAC sector has picked up momentum only in the last decade and hence the immediate change of technology may cause setbacks to the RAC sector 7.1.5.4 R134a Refrigerant For the past decade, R12 has been replaced with R134a in refrigerators and automobile air conditioners. At present in India more than 80% of the refrigerators are working with R134a 8. R134a possesesfavourable characteristics such as zero ODP, non-flammability, stability and similar vapour pressure to that of R12. Earlier studies indicate that the energy efficiency of R134a obtained in actual refrigerators was lower than that of R12 9.

1.5.5 Hydrocarbon Refrigerant Hydrofluorocarbons, such as R134a, have almost zero ozone depletion potential, as they do not contain chlorine atoms in their chemical structure. Similar to R12, they are safe, non inflammable and have similar vapour pressures 10.

However, they have lower energy efficiency and are more expensive than R12. They also have a low negative environmental effect of global warming potential 11. The concern against the increase of global warming has been the prior issue of study in the present century. Thus, in 1997 the Kyoto protocol was agreed by many countries there by calling for the reduction in emissions of greenhouse gases including HFCs.

The GWP of R134a is 1300 which is considerably high but lower than R12 12. Naturally occurring substances such as water, carbon dioxide, ammonia and hydrocarbons are believed to be environmentally safe refrigerants. Now in India CFCs phase out was successfully implemented by replacing R12 with R134a, but it has to be controlled due to relatively high GWP. So, interest towards environmentally safe refrigerants is growing. At the same time the performance of the refrigerants and their flammability are other crucial factors that have to be taken into account while selecting the refrigerants. Furthermore, it is desirable that the designed refrigerants, replace the current refrigerants without any major change in the system equipment. A trade-off point between all these factors has been considered while proposing the mixtures in the present work.

The aim of the present investigation is to find substitutes for R134a refrigerators. Using hydrocarbons is an environmentally sound alternative to CFCs/HFCs 13. HCs as a refrigerant have been used since the beginning of 20th century.

The development of the CFCs in the 1930s placed the HC technology in the background. Hydrocarbon technology has come to the forefront. Most of the natural refrigerants are also considerably cheaper than their synthetic alternatives 14. The general conclusion is that there is no ideal refrigerant today. Natural refrigerant should be chosen whenever possible for the sake of environment protection. In fact, hydrocarbons are known to have such advantages as low cost, availability, compatibility with the conventional mineral oils as well as PAG and POE 15.

However, their use has been held up in other developed countries mainly due to their high flammability. They offer other advantages of being very economical and easily available in large amounts. They are environmental friendly with zero ozone depletion potential, and they do not cause the greenhouse warming effect 16. The major limitation is that they are highly flammable substances and must be handled with caution. Also, blends of some refrigerants can be considered as substitutes or alternatives to existing refrigerants. There are an increasing number of scientists and engineers, including environmentalists who believe that an alternative solution, which has been overlooked, may be provided by using hydrocarbons. These provide the possibility of a zero ODP, together with suitable thermodynamic, physical and chemical properties.

It is possible to mix hydrocarbon refrigerants with other alternative refrigerants, such as HFC, to replace R134a in domestic refrigerators 10, 17, 18. Alternative refrigerants should have stable thermo physical and chemical properties, good miscibility with lubricants and low inflammability. The only limitation of hydrocarbons when compared to other refrigerants is flammability.

The reduction in flammability can be achieved by mixing HCs with HFCs 19. This process reduces the amount of flammable substance and consequently the flammability risk will be reduced. The global warming potential will be atleast two third less when HFCs are used alone. The proposed ternary mixture of HFC/HC used in this study has saturation properties matching with those of R134a. In fact, for the developing countries, meeting all the requirements of various international amendments for environmental protection is quite burdensome. Thus, a change in a major component in refrigeration equipment would be another serious hurdle preventing those countries from adopting energy-efficient and environmentally safe refrigerants. It is quite likely that the first component needs to be changed in adopting a new fluid would be a compressor 6. For such a case, it would be quite costly for those who implement it to redesign and retool all the manufacturing amenities for new compressors.

Thus, in order to adopt environmentally safe refrigerants at a reasonable cost, `drop-in replacement fluids’ requiring only minor changes in the system, particularly in the compressor, should be developed from the beginning to be used in the long run. In the present work, a general method of selecting `drop-in fluids’ is presented with a main application in visi cooler charged with R134a. To accomplish the goals of the study, a theoretical analysis as well as experimental investigation for the energy consumption and cooling performance is presented. The procedures and data presented in this work will be helpful for the replacement/reduction of ozone depleting/green-house warming refrigerants in the future. The point of contention surrounding the phase out of CFCs is to provide substitutes with optimum benefits and performance. In this work, an experimental study, using hydrofluorocarbon/hydrocarbon (HFC/HC) mixtures with suitable proportions, has been carried out to determine the optimum mixture for replacing R134a in existing visi coolers.

Non-azeotropic mixtures have some added advantages over single component and azeotropic refrigerants. The alternatives that are proposed in this report mainly comprise of non-azeotropic mixtures of R134a and hydrocarbons.1.6 Properties of good refrigerantLow boiling point and high latent heat of vaporizationNon-flammableLow toxicityLow miscibility with oilLow costGood heat transfer rateLow freezing pointLow power consumptionHigh efficiencyNegligible ODP,GWP The main objective in this study to development of Hydrocarbon blends “to study alternative refrigerants to replace R134a in a domestic refrigerator” and calculated EER, COP GWP, ODP in different methods like that practical, theoretical, software. The main function of this statistical models or use is Performance Evaluation of Domestic Refrigerator Using new eco- friendly Refrigerant as an Alternative with commonly used Refrigerant like that R32, R600a, R290, R12 And R134a.because of following reasons In India, about 80% of the domestic refrigerators use R134a as refrigerant due to its excellent thermodynamic and thermo physical properties. But R134a has high GWP of 1300.

The higher GWP due to R134a emissions from domestic refrigerators Leads to identifying a long term alternative to meet the requirements of system performance, refrigerant-lubricant interaction, energy efficiency, environmental impacts, safety and service. The Kyoto Protocol of the United Nations Framework Convention on Climate Change (UNFCCC) calls for reductions in emissions of six categories of greenhouse gases, including hydro fluorocarbons (HFCs) used as refrigerants. From the environmental, ecological and health point of view, it is urgent to find some better substitute for HFC refrigerants .Many investigators have reported that GWP of HFC refrigerants is more significant even though it has less than that of chlorofluorocarbons (CFC) refrigerants .Refrigerators are identified as major energy consuming domestic appliance in household environment.

Many researchers have reported that hydrocarbon mixed refrigerants is found to be an energy efficient and environment friendly alternative option in domestic refrigerators. The literature review brings out the fact that many researchers have studied with different hydrocarbon refrigerant mixtures as alternative to R12 and R134a in domestic refrigerators. However, the possibility of using HCM (composed of 45.2% of R290 and 54.8% of R600a) as R134a alternative at different ambient temperatures needs further investigation. The objective of the present study is to explore the possibility of using above mentioned HCM in a 150 l domestic refrigerator with different mass charges (40, 50, 60 and 70 g).

The influence of ambient temperatures on the performance characteristics of the refrigerator under continuous and cycling running operating mode at different freezer air temperatures with 32 ?C ambient temperature have been studied.1,2,…121.7 Refrigerant Selection In refrigeration and air conditioning systems selection of an appropriate working fluid is one of the most significant steps for a particular application. Low global warming potential has been inserted to the long list of desirable criteria of refrigerant’s selection. In fact, environmental characteristics of refrigerants are becoming the dominant criteria provided that their thermodynamic behaviors and safeties are favorable as well.1. Environmental impact and safety aspects 2. Zero ODP and Low GWP Refrigerant 1.

8 THEORETICAL AND RESEARCH STUDY OF ALTERNATIVE REFRIGERANTS TO R134aMany investigators have reported that GWP of HFC refrigerants is more significant even though it has less than that of chlorofluorocarbons (CFC) refrigerants. HCFCs (hydro chlorofluorocarbons) and CFCs (chlorofluocarbons) have been applied extensively as refrigerants in air conditioning and refrigeration systems from 1930s as a result of their outstanding safety properties. However, due to harmful impact on ozone layer, by the year 1987 at Montreal Protocol it was decided to establish requirements that initiated the worldwide phase out of CFCs. By the year 1992, the Montreal Protocol was improved to found a schedule in order to phase out the HCFCs. Moreover in 1997 at Kyoto Protocol it was expressed that concentration of greenhouse gases in the atmosphere should be established in a level which is not intensifying global warming ozone layer.

Subsequently it was decided to decrease global warming by reduction of greenhouse gases emissions.1. Characteristics of R134a and new proposed refrigerants:The properties of the refrigerants for wide range of temperatures (between ?60 and 60 °C) are compared in Figs. 1. Using Refprop 7 all properties can be evaluated and their comparison as shown in graphs. Fig. (a) depicts the variation of saturation pressure of R134a, R290, R600a, and blends of R290/R600a % by wt. (45.

2/54.8 HCM 1, 50/50 HCM 2, 54/46 HCM 3, 56/44 HCM 4, 60/40 HCM 5 and 68/32 HCM 6) against temperature. It was observed that all of the HCM has approximately the same vapor pressure as R134a in the evaporator temperature ranging between -60 and 100C. Hence the compressors can operate relatively at lower pressures with HCM than R134a. R290 has higher vapor pressure than R134a hence the compressor operate at higher pressure and R600a has very low vapor pressure (below atmospheric pressure) than R134a, thus increasing the possibility of drawing contamination in to the system in the event of a leak so that R600a is less suitable for low temperature applications. Hence with pure HCs (R290 and R600a) HC type compressor is needed.Fig.

1.6: Effect of temperature on (a) saturation pressure and (b) liquid density 4In Fig.1.

5 (b) Depicts the variation of liquid densities against temperature. It was observed that the liquid densities of all of the HCM and Pure HCs (R290 and R600a) refrigerants were found to be lower than that of R134a, as the liquid density is low it will significantly reduce the refrigerant charge requirement. Thus we can expect that if we will proceed with R290, R600a, and HCM it requires less charging amount as compare to that of the R134a. The other properties such as critical temperature, critical pressure, boiling point, molecular weight, ODP and GWP of R134a, R290, R600a and all of the HCM are compared in Table.Refrigerant ChemicalComposition N.

B.P°C Molecularweightg/mol CriticalTemp.°C CriticalpressureMPa GWPR134a CH2FCF3 -26.15 102 101.1 4.059 1300Propane(R290) CH3-CH2-CH3 -42.1 44.096 96.

675 4.247 3Isobutene (R600a) CH3-CH-CH3CH3 -11.73 58.12 134.

67 3.65 3R290/R600a(HCM1) 45.2/54.8 -31.13 50.816 118.

54 4.096 <20R290/R600a(HCM2) 50/50 -32.47 50.147 116.74 4.126 <20R290/R600a(HCM3) 54/46 -33.52 49.

602 115.22 4.154 <20R290/R600a(HCM4) 56/44 -34.01 49.334 114.45 4.

165 <20R290/R600a(HCM5) 60/40 -34.97 48.807 112.92 4.

186 <20R290/R600a(HCM6) 68/32 -36.72 47.786 109.8 4.22 <20Table 1.1:Alternative low GWP refrigerants to R134a.

7There are practical problems associated with the use of hydro fluorocarbon (HFC) refrigerants such as R134a:HFCs are not miscible with the mineral oils commonly used today. Polyol ester oils must be used instead of mineral oils. These are more dangerous to handle (contact with skin can cause problems) and more readily absorb moisture from air.The HFC and polyol ester oil mixture reacts in a different way, compared to R12 and mineral oils, with many seal materials. If these seals are not changed, leaks can occur.Polyol ester oils are more expensive. Servicing is more difficult for HFC systems.

HFCs and polyol ester oils are not as tolerant to moisture and other contamination in systems, so failures are more likely to occur if systems are not thoroughly cleaned and dehydrated before changing.It is not considered feasible to repair compressors after a burn out except in closely controlled conditions. This move away from HFCs has been further accelerated by concern caused by their potent global warming potentials. Some European countries have already decided to phase out HFCs because of this environmental problem.2. Hydrocarbon refrigerants:Hydrocarbons (HCs) are very good refrigerants for many reasons:They are compatible with copper and the standard mineral oils;They have a very low environmental impact in comparison with CFCs, HCFCs and HFCs;They perform very well, with good capacity and efficiency;Due to lower liquid densities, low refrigerant charge than that of HFCs;High heat transfer coefficients hence high latent heat of vaporization;Coefficient performance (COP) of the system increases and Power consumption reduced with HCs;Improves compressor life due to low discharge temperature compare to HFCs, HCFCs and CFCs;Service procedures can remain largely the same as for R12 and R22 refrigerants, except for safety considerations due to its flammability. However, HCs show relatively high flammability, but the flammability of the mixture of R290 and R600a is not a problem in a small- capacity refrigeration system with the refrigerant charge below 100g based on R134a. Very few changes are needed to a system and its components to be able to use HCs refrigerants.

However, care is needed to ensure that flammability does not present safety problems:Systems using HCs must be designed so that leakage is not dangerous.During charging, appropriate equipment should be used to charge the systems, and the charging area has to be chosen with care.Service technicians must be trained to handle HCs refrigerants safely.

1.9. OBJECTIVE OF PROJECTThe development of statistical models ,new hydrocarbon blends ,to investigate COP, GWP, ODP, EER of domestic refrigerator in different methods like that practical, theoretical, software.& Electric Power Consumption, Refrigeration Capacity, Compressor work and Coefficient of Performance (COP) by determining important parameters during in operating mode which are temperature, pressure with domestic refrigerator using Refrigerant R134a,R1234yf,Blends of R32,R600a,R290 at Constant Evaporator Temperature.1 To find out Actual COP of Refrigerant blend at different mixing ratio2 To investigate blends having zero ODP and GWP.3 To become aware about how to calculate EER and to give energy star rating of domestic refrigerator 4 To find out best suitable Alternative Refrigerant to Replace R134a in Domestic Refrigerator without any modification in VCR system.CHAPTER 2 LITERATURE REVIEW In recent past, R134a, R12 was used as working substance in domestic refrigerator. But use of R12 was abandoned because of ozone layer depletion (ODP) problem.

Or use of R12 was abandoned because of Global Warming Potential (GWP) problem now a day, R600a is used as working substance in domestic refrigerator. R600a (Hydrocarbon refrigerant) is used in domestic refrigeration and other vapor compression system. Mani et.al. 1 experiments are conducted using R12, R134a and R290/R600 mixture refrigerants. In this work the following conclusions are made. A five level factorial experimentation technique is employed for developing statistical models and the performance of R12, R134a and R290/R600 (79/21 by wt %) mixture are compared. The refrigerating capacity of R290/R600 (79/21 by wt %) is 49% higher for lower Te temperatures and 30% higher for higher Te than that with R12 and R134a R290/R600 mixture consumed 21.

3%-22.2% higher power than R12 and R134a at all the operating conditions due to the increased work of compression.The COP of R290/R600 (79/21 by wt %) mixture is 19.3%-27.

9% higher than that of R12 and the COP of R134a is close to that of R12 for the range of evaporating temperatures. Interaction effects of Te, Tcand N on RC, PC and COP for the refrigerants R12, R134a and R290/R600 are discussed using 3D plots. The investigated hydrocarbon mixture R290/R600 (79/21 by wt %) can be used as a possible alternative refrigerant for R12 and R134aJoybari et.al.

2 studied first energy analysis was carried out for 145 g of R134a. Then, R134a was replaced by 60 g of R600a, compressor was changed to a HC type one and energy analysis was applied to the refrigerator to improve its performance. According to the results, R600a charge amount, compressor COP and condenser fan rotational velocity were selected for Taguchi design. It was found that at optimum condition the amount of charge required for R600a was 50 g which is 66% lower than R134a one; Besides, R134a is about two times more expensive than R600a which makes R600a use economically beneficial. Compressor modification is strongly recommended to enhance the system.

Furthermore, the amount of total energy destruction in optimum condition (0.025 kW) is 45.05% of the base refrigerator one (0.05549 kW) which confirms the enhancement of the cycle for 54.95%.

.Exergy analysis of a refrigerator with 145 g of R134a showed that the compressor had the highest amount of exergy destruction followed by the condenser, capillary tube,evaporator and superheating coil had the highest exergydestruction.Using Taguchi design, the optimum condition was found to be R600a charge amount of 50 g, compressor coefficient of performance of 1.82 and condenser fan rotational velocity of 1800. The amount of charge required for R600a is 50 g, 66% lower than R134a one.The amount of total exergy destruction in optimum condition is 45.

05% of the base refrigerator one. sheikh et.al.

3 studied Energy Efficiency Ratio of R-600a is higher than R-134a. Experiment carried out using refrigerant R134a and R600a at in Domestic Refrigerator; it is found that cooling Capacity using Refrigerant for constant refrigeration effect is 107.03. Whereas for same refrigeration effect the cooling Capacity using Refrigerant R600a is 142.10.Compressor energy consumption of domestic refrigerator decreased by 10-15% with using refrigerant R600a.

Exergy analysis of a refrigerator with 145 g of R134a showed that the compressor had the highest amount of exergy destruction followed by the condenser, capillary tube,evaporator and superheating coil had the highest exergydestruction.Using Taguchi design, the optimum condition was found to be R600a charge amount of 50 g, compressor coefficient of performance of 1.82 and condenser fan rotational velocity of1800.The amount of charge required for R600a is 50 g, 66% lower than R134a one.

The amount of total exergy destruction in optimum condition is 45.05% of the base refrigerator one.Mahajan.et.

al. 4 studied the harmful refrigerants are to be phased out and are to be replaced with alternate environmental friendly refrigerants with zero ozone depletion potential (ODP) and negligible global warming potential (GWP), to replace R-12 and R134a in domestic refrigerator Hydrocarbons blends may replace R-134a without any system modifications. COP of the system is improved with reduced energy consumption. Hydrocarbon refrigerants are compatible with mineral oils (commonly used lubricants). Hydrocarbon technology provides a simple, sustainable and cost-effective solution for replacing R-134a in the domestic refrigeration subsector in developing countries. Kumar et.al.

5 R600 has the highest value of EER among R134a, R152a, R290, R600 and R600a at 40°C but at 55°C R600a has the highest value of EDR among R134a, R152a, R290, R600 and R600a.R600a has the highest value of Efficiency defect in compressor among R134a, R152a, R290, R600 and R600a.R290 has the highest value of Efficiency defect in throttle valve among R134a, R152a, R290, R600 and R600a.R600 has the highest value of Efficiency defect in evaporator among R134a, R152a, R290, R600 and R600a.This study presents a comparison of energy and exergy analysis for R134a, R152a, R290, R600 and R600ain refrigerator. The paper analyzes the domestic refrigerator with alternative refrigerants for computing coefficient of performance, exergy destruction ratio, exergy efficiency and efficiency defect. The method of exergy provides a measure to judge the magnitude of energy waste in relation to the energy supplied or transformed in the total plant and in the component being analyzed, a measure for the quality (or usefulness) of energy from the thermodynamic viewpoint and a variable to define rational efficiencies for energy systems. It is established that in the present work efficiency defect is maximum in condenser and lowest in evaporator.

Comparison of various properties for alternative refrigerants has been done for a domestic refrigerator.Jatav et. Al. 6 This review paper presents the work on the performance of condenser used in refrigeration system by the various researches. Micro channel condenser used to enhance the performance of various parameters like heat transfer, pressure drop, energy efficient ratio, COP and refrigerant effect of the system.

In refrigeration system condenser is a vital part. Micro channel heat exchanger has been increasingly applied in HVAC&R (Heating, ventilation and air conditioning &refrigeration) field due to its higher efficiently heat transfer rate more compact structure.The COP of the system has been improved with the hydrocarbon refrigerants. The average COP of HC 19% higher than that of R134a.The domestic refrigerator was charged with 60g in 134a and 40g of HC. This is indication of better performance of HC as refrigerants.

Refrigeration efficiency of the system increases with the increases in condensing and evaporating temperature. Mass flow rate is reduced when we are using hydrocarbon as refrigerant.Bhargav et.al. 7 He Studied that A domestic refrigerator designed to work with R134 a was investigated to assess the possibility of using a mixture of propane and iso butane. The performance of the refrigerator using azotropic mixture as refrigerant wasinvestigated and compared with the performance of refrigerator when R134a, R12, R22, R290, R600a is used as refrigerant. The effect of condenser temperature and evaporation temperature on COP, refrigerating effect, condenser duty, work of compression and Heat Rejection Ratio where investigated. The energy consumption and COP of hydrocarbons and there blends shows that hydrocarbons can be used as refrigerant in the domestic refrigerator The paper deals with the energy analysis of mixture and of propane and iso butane with R12 and R134a.

The cycle considered for study is having super heatedvapour after compression. Efforts have been made toconsider super cooling also.comparison of mint gas is done with R-12 and R-134 for in domestic refrigerators. From the observation we found that mint gas can be an option which could produce better results. Al though its implementation requires a detail experimental calculations. Mint gas is providing more COP then ordinary refrigerants another advantage of this refrigerant was that it does not react with compressor oil. The only disadvantage associated with this gas is its flammability, which can be an obstacle in its implementation. This problem can be solved by proper design of the refrigerator.

Cabello et.al.8 studied the influence of the evaporating pressure, condensing pressure and superheating degree of the vapour on the exergetic performance of a refrigeration plant using three different working fluids R134a, R407c, R22.

In this paper, the influence of the main operating variables on the energetic characteristics of a vapour compression plant, based on experimental results, is addressed. The experimental tests are performed on a single-stage vapour compression plant using three different working fluids, R134a, R407C and R22.The operating variables considered are the evaporating pressure, the condensing pressure and the superheating degree at the compressor inlet.

The performance characteristics followed to analyse the energetic performanceare the refrigerating capacity and the power requirements of the reciprocating compressor, presenting and discussing in this work the main experimental results obtained. Kumar et. al. 9 studied the behavior of HCFC (Hydrochloroflurocarbon) -123/ HC-290 refrigerant mixture computationally as well as experimentally and found that refrigerant mixture 7/3 as a promising alternative to R12 system.At the advent of the Montreal protocol, R134a has been suggested as an alternate refrigerant to R12. R134a is a high global warming potential gas and needs to be controlled as per the Kyoto protocol. It is reported that there is no single refrigerant or mixture available to satisfy both the ozone depletion potential (ODP) and global warming potential (GWP) issues. In this scenario, the objective of this work was, to develop an eco-friendly refrigerant mixture with negligible ODP and GWP values that is nearly equivalent to R12 in its performance.

R123 is a potential refrigerant with very low ODP and GWP values, but due to its high suction specific volume and high boiling point, it has not been considered as an alternate refrigerant to R12. In this work, to overcome the above said problems, R290 has been identified as suitable for combination with R123 in a refrigerant mixture. Using REFPROP for analysis, it was found that the performance parameters for a mixture containing 70% R123 and 30% R290 were near matching with R12. This has been further confirmed experimentally by conducting a base line test with R12 and tests with the new mixture. The flow characteristics of the mixture were compared with R12 and presented. Bolaji et.al. 10 investigated experimentally the performances of three ozone friendly Hydrofluorocarbon (HFC) refrigerants R12, R152a and R134a.

R152a refrigerant found as a drop in replacement for R134a in vapour compression system.In this paper, the performances of three ozone-friendly Hydrofluorocarbon (HFC) refrigerants (R32, R134a and R152a) in a vapour compression refrigeration system were investigated experimentally and compared. The results obtained showed that R32 yielded undesirable characteristics, such as high pressure and low Coefficient of Performance (COP). Comparison among the investigated refrigerants confirmed that R152a and R134a have approximately the same performance, but the best performance was obtained from the used of R152a in the system. As a result, R152a could be used as a drop-in replacement for R134a in vapour compression refrigeration system.

The COP of R152a obtained was higher than those of R134a and R32 by 2.5% and 14.7% respectively. Also, R152a offers the best desirable environmental requirements; zero Ozone Depleting Potential (ODP) and very low Global Warming Potential (GWP)Balakrishnan et.al.11 studied that,This paper explores an experimental investigation of an alternative eco-friendly refrigerant for R134a with a better Coefficient Of Performance (COP), reduced Global Warming Potential (GWP) and Ozone Depletion Potential(ODP). This investigation has been accessed using a hydrocarbon refrigerant mixture composing of R32/R600a/R290 in the ratio of 70:5:25 by weight. The performance characteristics of the domestic refrigerator were predicted using continuous running tests under different ambient temperatures and cyclic running (On/Off) tests at the fixed temperatures i.

e., evaporation temperature (-5?C) and condensation temperature (30?C). The obtained results showed that the hydrocarbon mixture has lower values of energy consumption; pull down time and ON time ratio also higher Coefficient of Performance (COP).

Thus, the performance of the alternate refrigerant derives the better choice than R134a. Dalkilic et. al. 12 studied the A theoretical performance study on a traditional vapour-compression refrigeration system with refrigerant mixtures based on HFC134a, HFC152a, HFC32, HC290, HC1270, HC600, and HC600a was done for various ratios and their results are compared with CFC12, CFC22, and HFC134a as possible alternative replacements. In spite of the HC refrigerants’ highly flammable characteristics, they are used in many applications, with attention being paid to the safety of the leakage from the system, as other refrigerants in recent years are not related with any effect on the depletion of the ozone layer and increase in global warming.

Theoretical results showed that all of the alternative refrigerants investigated in the analysis have a slightly lower performance coefficient (COP) than CFC12, CFC22, and HFC134a for the condensation temperature of 50 °C and evaporating temperatures ranging between ?30 °C and 10 °C. Refrigerant blends of HC290/HC600a (40/ 60 by wt.%) instead of CFC12 and HC290/HC1270 (20/80 by wt.%) instead of CFC22 are found to be replacement refrigerants among other alternatives in this paper as a result of the analysis. The effects of the main parameters of performance analysis such as refrigerant type, degree of subcooling, and superheating on the refrigerating effect, coefficient of performance and volumetric refrigeration capacity are also investigated for various evaporating temperatures.performance analysis of alternative new refrigerant mixtures as substitute for R12, R134a and R 22.

Refrigerant blend of R290/R 600a (40/60 by wt. %) and R 290/R1270 (20/80 by wt. %) are found to be the most suitable alternative among refrigerants tested for R12 and R22.

Wongwises et.al. 13 found that 6/4 mixture of R290 and R600 is the most appropriate refrigerant to replace HFC134a in a domestic refrigerator. This work presents an experimental study on the application of hydrocarbon mixtures to replace HFC- 134a in a domestic refrigerator. The hydrocarbons investigated are propane (R290), butane (R600) and is butane (R600a). A refrigerator designed to work with HFC-134a with a gross capacity of 239 l is used in the experiment. The consumed energy, compressor power and refrigerant temperature and pressure at theinlet and outlet of the compressor are recorded and analysed as well as the distributions of temperature at various positions in the refrigerator. The refrigerant mixtures used are divided into three groups: the mixture of three hydrocarbons, the mixture of two hydrocarbons and the mixture of two hydrocarbons andHFC-134a.

The experiments are conducted with the refrigerants under the same no load condition at a surrounding temperature of 25 _C. The results show that propane/butane 60%/40% is the most appropriatealternative refrigerant to HFC-134a.Reddy et.al. 14 studied the present review on the alternative refrigerants used in the domestic refrigerators to have better performance with minimum losses. This paper give the summary and range of various refrigerants used in the domestic refrigerators. of global warming which affect the environment by the use of refrigerant, and our aim is to reduce the effect of global warming as well as optimize the performance of domestic refrigerators by using the latest refrigerants. This review paper represents the recent developments done in domestic refrigerator.

Performance of refrigerator is increased by using different refrigerants. R134a is used in domestic refrigeration and other vapor compression system. R134a is having zero ozone depletion potential (ODP) and almost good thermodynamic properties, but it has a high Global Warming Potential (GWP) of 1300.The higher GWP due to R134a emissions from domestic refrigerators leads to identifying a long term alternative to meet the requirements of system performance, Therefore it is going to be banned very soon for environmental safety. Some new refrigerants is been found by researchers which are environmental friendly refrigerants having low GWP and low ODP. Hydrocarbon refrigerants particularly propane, butane and isobutene are proposed as an environment friendly refrigerants.

After reviewing the various literatures on the hydrocarbons (R290 and R600a) refrigerants and their mixture gives good performance in small capacity domestic refrigerator to replace R134a.Bhatkar et. al. 15 Vapour compression refrigeration is used in almost 80 % of the refrigeration industries in the world for refrigeration, heating, ventilating and air conditioning. The high-grade energy consumption of these devices is very highand the working substance creates environmental problems due to environmental unfriendly refrigerants such as chloroflurocarbons, hydrochloroflurocarbons and hydroflurocarbons. Heating, ventilating, air conditioning and refrigeration industries are searching for ways to increase performance, durability of equipments and energy efficiency in a sustainable way while reducing the cost of manufacturing. With the present refrigerants, environmental problems such as ozone layer depletion, global warming potential, green house gases and carbon emission are increasing day by day.

In this paper, the popular refrigerant is thoroughly studied experimentally and recommendations are given for alternatives such as carbon dioxide, ammonia and hydrocarbons and new artificially created fluid, Hydro- Fluoro-Olefin 1234yf by DuPont and Honeywell which exhibit good thermo-physical and environmental properties and will be commercialized in the near future.Agrawal et.al. 16 worked on eco-friendly refrigerant as a substitute for CFC (Chloroflurocarbon). The binary mixture in the ration of 64% and 36% of R290 and R600a found to be a retrofit or drop in substitute of R12 for use in the vapour compression refrigeration trainer.

He works on the study hydrocarbon refrigerants R600a and R290, in that he concludes that the bleds of R600a and R290 in mixture ratio of 64% and 36% is best suitable alternative to R134a.Arora et.al. 17 had worked on a detailed analysis of an actual vapour compression refrigeration cycle.

A computational model had been developed for computing coefficient of performance, exergy destruction, exergetic efficiency and efficiency defects for R502, R404A and R507A. The investigation had been done for evaporator and condenser temperatures in the range of -50°C to 0°C and 40°C to 55°C respectively. The results indicate that R507A was a better substitute to R502 than R404A. This paper presents a detailed exergy analysis of an actual vapour compression refrigerationb(VCR) cycle.

A computational model has been developed for computing coefficient of performance (COP), exergy destruction, exergetic efficiency and efficiency defects for R502, R404A and R507A. The present investigation has been done for evaporator and condenser temperatures in the range of _50 _C to 0_C and 40 _C to 55_C, respectively. The results indicate that R507A is a better substitute to R502 than R404A.

The efficiency defect in condenser is highest, and lowest in liquid vapour heat exchanger for the refrigerants considered. Padilla et. al.18 found that R413A (mixture of 88% R134a, 9%R218, 3%R600a) can replace R12 and R134a in domestic refrigerator,study deals with an exergy analysis of the impact of direct replacement (retrofit) of R12 with the zeotropic mixture R413A on the performance of a domestic vapour-compression refrigeration system originally designed to work with R12. Parameters and factors affecting the performance of both refrigerants are evaluated using an exergy analysis. In the literature, no experimental data for exergy efficiencyare reported, so far, for R413A.

Twelve tests (six for each refrigerant), are carried out in a controlled environment during the selected cooling process from evaporator outlet temperature from 15 _C to _10 _C. The evaporator and condenser air-flows are modified to simulate different evaporator cooling loads and condensers ventilation loads. The overall energy and exergy performance of the system working with R413A is consistently better than that of R12.

Tayde et.al. 19 design and investigated with classical refrigeration using vapour compression has been widely applied over the last decades to large scale industrial systems. Now, the mini-scale (miniature) refrigerator using VCR seems to be an alternative solution for the electronic cooling problem. Fabrication of very small devices is now possible due to advances in technology.

In this investigation a mini-scale refrigerator of 300W cooling capacity using R-134a as refrigerant is designed, built and tested. This test indicates that the actual COP of the developed system is 1.6 and second law efficiency is 19%.Ankitunde et.al. 20 In the vent of chlorofluorocarbons (CFCs) phase-out, identify long term alternative to meet requirements in respect of system performance and service is an important area of research in the refrigeration and are conditioning industry. This work focuses on experimental study of the performance of eco-friendly refrigerant mixtures. Mixtures of three existing refrigerants namely: R600a (n-butane), R134a (1,1, 1,2,tetrafluoroethane) and R406A (55%R22/4%R600a/41%R142b) were considered for this research.

These refrigerants were mixed in various ratios, studied and compared with R-12 (dichlorodifluoromethane) which was used as the control for the experimentation. The rig used in the experimentation is a 2 hp (1.492 kW) domestic refrigerator, designed based on condensing and evaporating temperatures. The rig was tested with R-12, and blends of the three refrigerants. During the experimentation, both evaporator and condenser temperatures were measured. These were used to determine the heat absorbed in evaporator and the heat rejected incondenser. The results show that R134a/R600a mixture in the ratio 50:50 can be used as alternative to R-12 in domestic refrigerators, without the necessity of changing the compressor lubricating oil.

At and , R-12 gives a COP of 2.08 while 50:50 blend of R134a/R600a gives a COP of 2.30 under the same operating conditions. Sattar et.al.

21 studied the domestic refrigerator designed to work with R-134a was used as a test unit to assess the possibility of using hydrocarbons and their blends as refrigerants. Pure butane, isobutene and mixture of propane, butane and isobutene were used as refrigerants. The performance of the refrigerator using hydrocarbons as refrigerants was investigated and compared with the performance of refrigerator when R-134a was used as refrigerant. The effect of condenser temperature and evaporator temperature on COP, refrigerating effect, condenser duty, work of compression and heat rejection ratio were investigated. The energy consumption of the refrigerator during experiment with hydrocarbons and R-134a was measured.

The results show that the compressor consumed 3% and 2% less energy than that of HFC-134a at 28 °C ambient temperature when iso-butane and butane was used as refrigerants respectively. The energy consumption and COP of hydrocarbons and their blends shows that hydrocarbon can be used as refrigerant in the domestic refrigerator. The COP and other result obtained in this experiment show a positive indication of using HC as refrigerants in domestic refrigerator.

Baskaran et.al. 22 determined the performance analysis on a vapour compression refrigeration system with various eco-friendly refrigerants of HFC152a, HFC32, HC290, HC1270, HC600a and RE170 were done and their results were compared with R134a as possible alternative replacement. The results showed that the alternative refrigerants investigated in the analysis RE170, R152a and R600a have a slightly higher performance coefficient (COP) than R134a for the condensation temperature of 50 C and evaporating temperatures ranging between -30 C and 10 C.Refrigerant RE170 instead of R134a was found to be a replacement refrigerant among other alternatives. The effects of the main parameters of performance analysis such as refrigerant type, degree of sub cooling and super heating on the refrigerating effect, coefficient of performance and volumetric refrigeration capacity were also investigated for various evaporating temperatures.Aasim et.al.

23 investigated experimental study of isobutene (R-600a), an environment friendly refrigerants with zero ozone depletion potential (ODP) and very low global warming potential (GWP), to replace R-134a in domestic refrigerators. A refrigerator designed to work with R-134a was tested, and its performance using R-600a was evaluated and compared its performance with R-134a. The average COP using R-600a was 27% higher than R-134a respectively. The power consumption by compressor reduced by 3.7% with R600a refrigerant.

The compressor ON time ratio was lowered by 6.98% with R-600a compared with R- 134a. The experimental results showed that R-600a can be used as replacement for R-134a in domestic refrigerator.

Daviran et.al. 24 Studied that the automotive air conditioning system is simulated by considering HFO-1234yf (2,3,3,3- tetrafluoropropene) as the drop-in replacement of HFC-134a.

The simulated air conditioning system consists of a multi-louvered fin and flat-plate type evaporator, a wobble-plate type compressor, a minichannel parallel-flow type condenser and a thermostatic expansion valve. The thermodynamic properties of the refrigerants are extracted from the REFPROP 8.0 software, and a computer program is simulated for the thermodynamic analysis. Two different conditions have been considered in this program for the cycleanalysis: for the first state, the cooling capacity is taken as constant, and for the second state the refrigerant mass flow rate is considered fixed. The performance characteristics of system including COP and cooling capacity have been studied with changing different parameters. The results show that the refrigerant-side overall heat transfer coefficient of HFO-1234yf is 18–21% lower than that of HFC-134a,and the pressure drop is 24% and 20% smaller than HFC-134a during condensing and evaporating processes, respectively. Also, in a constant cooling capacity, the COP of HFO-1234yf is lower than HFC- 134a by 1.3–5%, and in the second case the COP of HFO-1234yf is about 18% higher than that of HFC-134a.mohanraj et.al.25 studied that the energy performance of a domestic refrigerator has been assessed theoretically with R134a and R430a as alternative refrigerant. and he concludes that R430a has a low gwp of 109 as compare to R134a. In this work, the energy performance of a domestic refrigerator has been assessed theoretically with R134a andR430A as alternative refrigerant. The performance has been assessed for three different condensing temperatures, specifically, 40, 50 and 60 °C with a wide range of evaporator temperatures between ?30 and 0 °C. Theperformance of the domestic refrigerator was compared in terms of volumetric cooling capacity, coefficient of performance, compressor power consumption and compressor discharge temperature. Total equivalent global warming impact of the refrigerator was assessed for a 15-year life time. The results showed that volumetriccooling capacities of R430A and R134a are similar, so that R134a compressor can be used for R430A without modifications. The coefficient of performance of R430A was found to be higher than that of R134a by about 2.6–7.5% with 1–9% lower compressor power consumption at all operating temperatures. The compressor discharge temperature of R430A was observed to be 3–10 °C higher than that of R134a. Total equivalent global warming impact of R430Awas found to be lower than that of R134a by about 7% due to its higher energy efficiency. The results confirmed that R430A is an energy efficient and environment-friendly alternative to R134a indomestic refrigerators.Vaghela 26 is derived that R1234yf is best suitable is best suitable alternative refrigerant to R134a.he concludes that R1234yf has lower cop as compared to R134a;however it is best suitable refrigerant as drop in substitute because it has very low GWP and can be substituted in the existing automobile air conditioning system with minimum modification.Rasti et.al.27studied that substitution of two hydrocarbon refrigerants instead of R134a in domestic refrigerator. experiments are designed on a refrigerator manufactured for 105 g R134a charge.the effect of parameters including refrigerant type, charge and compressor type are investigated. his research is conducted using R436a and R600a as a hydrocarbon refrigerant.This paper is devoted to feasibility study of substitution of two hydrocarbon refrigerants instead of R134a in a domestic refrigerator. Experiments are designed on a refrigerator manufactured for 105 g R134a charge. The effect of parameters including refrigerant type, refrigerant charge and compressor type are investigated. This research is conducted using R436A (mixture of 46% iso-butane and 54% propane) and R600a (pure iso-butane) as hydrocarbon refrigerants, HFC type compressor (designed for R134a) and HC type compressor (designed for R600a). The results show that for HFC type compressor, the optimum refrigerant charges are 60 g and 55 g for R436A and R600a, respectively. Moreover, for this type of compressor, the energy consumption of R436A and R600a at the optimum charges is reduced about 14% and 7%, respectively in comparison to R134a. On the other hand, when using HC type compressor, the optimum refrigerant charges for R436A and R600a are both 50 g, and the energy consumption of R436A and R600a at the optimum charges are reduced about 14.6% and 18.7%, respectively. Furthermore, when the refrigerator is equipped with HC type compressor, working under optimum charges of R436A and R600a have a total equivalent warming impact about 16% and 21% lower than base refrigerator, respectively. Totalexergy destruction of the domestic refrigerator with HFC type compressor for R134a, R600a and R436A are 0.0389, 0.0301, 0.0471, respectively and for R600a and R436A with HC type compressor are 0.0292, 0.0472, respectively.2.1.Research Gap:By studying the all above literature research ,They have done various experiments by using different refrigerant like R12,R290,R600a,R436a,R430a,pure and blends of hydrocarbons etc.by studying all these parameters I am going to study with different hydrocarbon blends of R32,R600a,R290.also by using R1234yf which is joint venture of Dupont and Honeywell in domestic refrigerator without any modification in VCR system.CHAPTER 3 DESIGN AND DEVELOPMENT OF EXPERIMENTAL SYSTEM3.1 Details of Experimental SetupTable 3.1: Details of Experimental SetupSI NO Description Dimension/Range1 Refrigerator Capacity 170 litres2 Capillary Tube 0.031mm 3 Compound Gauge -30-220psi4 Pressure guage0-250 psi5 Vaccum Pump -30PSIG6 R32/R600a/R290 76 gmThe R134a domestic refrigerator setup consist of a hermatically sealed compressor ,natural convection air cooled condenser having a cooling capacity level of 5.67KW/hr, an evaporator and copper capillary tube whose schematic diagram and photographic view of the experimental set up is given in the fig .Sensor is attached at the inlet and outlet of compressor, condenser and evaporator. Pressure gauge is attached at the compressor inlet and outlet. Compound gauge is fitted at the condenser outlet. Evacuation of moisture takes place with the help of service port service port. Vaccum pump is used for evacuation and through the charging system refrigerant was filled in the refrigeration system. 3.2 Compressor: A refrigerant compressor, as name indicates, is a machine used to compress the vapor refrigerant coming out from an evaporator and to raise its pressure. It also continuously circulates the refrigerant through refrigeration system. Since the compression of refrigerant requires some energy input for performing its function, therefore a compressor must be driven by some prime movers. There are three types of compressor which are common in used, they are 1. Reciprocating Compressor a. Hermetically sealed. b. Semi hermetically sealed. c. Open type 2. Centrifugal compressor 3. Rotary compressor The compressor used in this research work was hermetically sealed reciprocating type compressor. In which motor was enclosed along with the cylinder and crank case, inside the dome. The motor windings were cooled by incoming suction vapor. These have the advantages of no leakage, less noise and compactness.Design of Compressor: 29Volume flow rate through compressor V= QDV1/(h1-h4) where, Design load QD = 0.46 Kw , h1= 412 KJ/Kg , h4 = 257 KJ/Kg V = 0.00074 m3/sec rpm of compressor N= 120cf / npwhere, frequency cf =50Hz, no. of poles = 2 , N=3000 rpm Cylinder bore d = {( 240/?) QDV1 / nvaN (h1-h4)}1/3 14 nva = 1 – (vc/vs) (r1/1.4-1) where, compression ratio r = P2/p1 = 13.33 , Taking vc/vs = 0.03 Nva = 83 % Cylinder bore d = 6.1 mm The length of stroke may be assumed 1 to 1.2 of bore L = 7.32mm Vs= V/nvTable 3.2: Compressor specifications:Description SpecificationModel K444 HAGCapacity 0.46 KWSuction Pressure 2.8 kg/cm2Discharge pressure 13.8 kg/cm2Bore 6.1 mm3.3.Condenser :Refrigerant from compressor passes through air cooled condenser. The function of condenser is to remove or reject heat of the hot vapor refrigerant discharged from the compressor to the atmosphere. The hot vapor refrigerant consists of heat observed by the evaporator and heat of compression added by the mechanical energy of the compressor motor. In air cooled condenser air is used as cooling medium. The axial fan is used in the setup so as to undergo forced convection in order to achieve more cooling by the condenser. 15 Condenser Design :The inner and outer diameter and length of the condenser tubes are as follows, di=6mm d0=9.37mm L= 3.6m Overall heat transfer coefficient U is given by, 1/U = A+(B/V0.8) U=2.14 W/m2 0C Q=UA?mThe log mean temp. difference?m= ?1-?2 /In (?1/?2) Assume ambient air temperature as 300C, condenser inlet temperature as 1100C and condenser outlet temperature as 400C. ?m= 38.830C Capacity of condenser is given by Q = m (h2-h4) m=0.003kg/sec , h2=457KJ/kg , h4 = 257KJ/k Q = 0.6 KJ/sec A= Q/U ?mA= 0.009 m2 A=?.d0L.n No of coils n =12 16 28Table 3.3 : Condenser specificationsDescription SpecificationMaterial of Coil CopperDiameter of Coil 9.37 mmLength of Tube 3.6 mNo.of Rows 3Nos01Condenser Type Air cooled condenser3.4 Capillary tube :- Capillary tube is one of the most throttling devices in the refrigeration systems. The capillary tube is a copper tube of very small internal diameter. It is of very long length and it is coiled to several turns so that it will occupy less space. The internal diameter of the capillary tube used for the refrigeration. Capillary tube design :- 28The compressor work per unit mass is given by w = (h2-h1) , w= 45KJ/kg Compression capacity for 0.5 KW = mqc x 3600 = (0.5/w)xqcx3600= 6200 KJ/hrCorresponding to 6200 KJ/h and 1.25mm capillary tube Length is found to be L=3m (capillary tube length Vs Compressor capacity graph) 17 Fig 3.1 Cappillary tube vs Compressor Capacity3.5 Evaporator: 28An evaporator is a device used to evaporate from liquid to gas while absorbing heat in the process. It can also be used to remove water or other liquid from mixtures. Evaporator Design – Inner diameter and length of coil d0=7.81mm, L=9m Q= m( h1-h4) where, h1=412 KJ/Kg , h4=257 KJ/Kg Q = 0.46 KW Consider fluid enters evaporator at 270K ; leaves at 262 K, boilling temperature of refrigerant= 258 K ?m= ?1-?2 /In (?1/?2) ?m= 7.2 K A = Q/ U?mWhere, U= 2.14 KJ/m2-m-s, A = 0.03 m2 A = ?d L n No of tubes n =18 Table 3.4: Evaporator specificationsDescription SpecificationMaterial of coil CopperDiameter of coil 7.81 mmLength of tube 9 mNos023.6 Energy meter: The energy meter is provided in the system that measures the power consumption by each and every component of the system such as the refrigerator, condenser fan, digital temperature indicator, etc.3.7 Pressure gauges: Two pressure gauges are mounted in the system to measure the pressures of suction and delivery sides. The suction gauge and delivery gauge a range from 0 to 250 psi.3.8. Thermocouples: The thermocouples are K type and have the range of -50 0c to 70 0c (108 0c Maximum measurable).3.9 METHODOLOGYThe first step is to study the alternative refrigerant to replace R134a in a domestic refrigerator.3.5 Properties of R32/R600a/R290 refrigerant given in the Table 4.2. 11Table 3.5: Properties of R32/R600a/R290Refrigerant R32 R600a R290Safety level A1 A1 A1Boiling point(oc) -52 -11 -41Tcon(oc) 78.1 137.7 66Pcond (bar) 5.78 3.78 3.62COP 2.11 1.99 2.01ODP 0 0 0GWP 71.5 -20 -20Methodology of this work is concentrated on two important things that need to be developed in order to investigate the performance of the domestic refrigerator which is location of measurement points and it devices, and experiment set-up.3.9.1 Development of Location of Measurement PointsRefrigerator test rig was developed in order to investigate the performance of the system. In developing the reliable refrigerator test rig, consideration should be highly addressed especially the development method and measurement locations of pressure and temperature. They discussed the locations of temperature and pressure measurement points, measurement devices and measurement methods. As a result, a refrigerator test rig was developed. There are five points of temperature measurement, two points of pressure measurement and one is energy measurement. 8From the five points of temperature measurement, four points have been placed inside the refrigeration circuit to measure refrigerant temperature and another one points have been placed in refrigerator compartments. The thermocouple wire was used to measure the temperature of refrigerant in the tube. The technique to measure the temperature where the thermocouple wire was put inside the refrigerant tube so that the measurement made was exactly the temperature of the refrigerant. However, the method to construct the sensor was different. Figure shows the method to construct the temperature measurement point in the refrigerant tube.8By using this method, as shown in Figure was used to hold a thermocouple wire which was inserted into the tube and effectively sealed, as shown in Figure . The flared tube is fitted securely on to a copper J-junction which was then joined mechanically to the tube to reconnect every two consecutive components. The temperature of the refrigerant which now flowed through each J-junction was measured by the hot thermocouple junction or head, as shown in Figure . Prior to installation each thermocouple was calibrated using a platinum thermocouple against temperature of freezing point, room condition and boiling point of water.The thermocouple used was of J-type, 0.3 mm diameter and designed for temperature range between -50°C to 99°C. The accuracy is about ±2%.Fig 3.2: Fabrication of Assembly method of ThermocoupleBesides that, two points of pressure were tapped respectively made on pipes connecting all main components. Bourdon Tube pressure gauges were used for each pressure measurement in this test rig (ANSI/ASHRAE Standard, 1989, ARI 1998). A tube with diameter 2.1 mm was used to connect the refrigerant tube to each pressure gauge as what was done by Philipp. Figure 4 shows the detail construction of the pressure measurement points. 8Fig 3.3: Assembly method of pressure measurement using Bourdon type pressureFig 3.4: Fabrication of Assembly method of pressure measurement using Bourdon type pressureCHAPTER 4 . EXPERIMENTAL SETUPIn short the experimental setup consists of following component: 31) Vapour compression refrigeration unit Compressor Condenser Expansion device (capillary tube)Evaporator2) Energy meter3) Five thermo-couple with digital display4) Two pressure gauge5) Main switch ; indicatorFig 4.1: schematic dia1gram of a refrigeration system experimental setup system a) Front view b) Back side viewc) Reading panel Front view d) Reading panel Back side viewFig 4.2: Actual Experiment Set-up4.1 Experimental procedureTake known quantity of water in can.Measure initial temperature of water and note down.The can is place in freezer compartment.The thermocouple no.5 dipped into water (water can)Start the system by main switching on the compressor.Start the stop watch.Measure the initial suction and discharge pressure of compressor.When ice is formed then stops the stop watch and measures all temperatures T1, T2, T3, T4, and T5.and measure the final suction and discharge pressure of compressor.Use different formulas and get the calculated EER, COP in different methods. 4.2 PRECAUTIONS: 1) Maintain constant power supply to compressor. 2) Maintain the required pressure in the system. 3) Maintain the required level of water in the cane. 4) Do not open charging valve unless required for charging. 5) Do not open refrigerator door.4.3 FORMULAE AND SAMPLE CALCULATION4.3.1Energy Efficiency Ratio (EER): 3Energy Efficiency Ratio is defined as the ratio of heat removed in B.Th.U.to Electrical Power Consumption in W.hr is known as the Energy Efficiency Ratio. EER= Heat Removed in B.Th.U.Electric Power Consumption in W.hr 1Where,Heat removed in B.Th.U= R.E(KJ)1.055 = 462.321.055 =438.211B.Th.U=1.055 KJHence, EER= 438.21400 =1.0955.4.3.2.Coefficient of Performance (COP): 3The coefficient of performance (COP) is expressed as COP or coefficient of performance which defined as Refrigeration Effect to Compressor Work.a Actual COP COP=Refrigerating Effect(R.E.)Cooling Effect(Win) 2Where,R.E. =M {Cpw(Tw-0) +L+Cpice (0-Tice)},KJ 3M=Mass of WaterCpw =Specific Heat of WaterCpice = Specific Heat of IceL =Latent HeatTw =Initial Temp. of WaterTice=Ice Temp.R.E. =1{4.19(28-0) +335 +2(0-(-5))}R.E.= 462.32 KJ.Win =0.380×3600 =1368 KJ.COP = =462.321368 =0.3379.b Theoretical COPCOP=h1-h4h2-h1 4Where, h1= After Evaporation Enthalpy h2= After Compression Enthalpy h3= After Condensation Enthalpy h4= After Expansion EnthalpyT1= After Evaporation Temp T2= After Compression Temp T3= After Condensation Temp T4= After Expansion TempC EER (Based on COP)EER=3.41×COP 5 = 3.41×0.3379 = 1.1522.3 Energy Consumption Calculation1. Normal Working Hour of a Refrigerator in a day = 6 Hr/Day 2. Actual working of Compressor “Cut In& Cut Out” Condition is 70 % =4.2 hr/day comp runs time.4 Calculation of Energy Efficiency Ratio (EER) for Related Star Rating EER=Energy ConsumptionkwhyearAdjusted Volume(Litre) 6Where,Adjusted volume =FFV+FZV×K×FcFFV = fresh food compartment volume FZV = freezer compartment volume K = adjustment factorFc = frost free factorK=Room Test Temp.-Freezer Compartment Temp.Test Room Temp.-Fresh Food Compartment Temp = 34-(-15)34-(-10) 7K =1.1136Adjusted volume =170×1.1136×1.6 = 302.90.Electric power consumption of 170 ltr = 0.750 unit/day = 274 unit/ yrRate per unit =6.81 rsElectric power consumption per day =0.75×6.81= 5.1075 rs.Electric power consumption per month = 5.1075×30 = 153 rsElectric poer consumption per year = 153×12 =1839 rs.EER=274302.90= 0.9045.Table 4.1: Relation between EER and Star RatingProposed Grading System (EER)1 Star ? 1.452 Star 1.23 ? EER ? 1.443 Star 1.01 ? EER ? 1.224 Star 0.81? EER ? 1.005 Star EER? 0.80EER of given refrigerator with Blend no.1 (mixing ratio:0/80/20) =0.9045.Hence given refrigerator with mixing ratio of (0/80/20) is four star rated.CHAPTER 5. RESULT ; DISCUSSIONInitial temperature of water Tw =280CTemperature of ice (Tice)=-50CMass of water = 1 KgSpecific heat of water(Cpw) = 4.19 KJ/KgK 28Specific heat of ice (Cpice) = 2 KJ/Kgk 28Latent heat (L) = 335 kJ/KgTable 5.1:- Experimental COP and EER of R32/R600a/R290Blend No. Refrigerants Mixing ratio COP EER1 R32/R600a/R290 0/80/20 0.3379 1.15312 R32/R600a/R290 10/70/20 0.3279 1.12363 R32/R600a/R290 20/60/20 0.3210 1.09554 R32/R600a/R290 30/50/20 0.3132 1.06885 R32/R600a/R290 40/40/20 0.2620 0.89436 R32/R600a/R290 50/30/20 0.2518 0.85927 R32/R600a/R290 60/20/20 0.2253 0.76878 R32/R600a/R290 70/10/20 0.2105 0.71839 R32/R600a/R290 80/0/20 0.1975 0.6741Fig-5.1 COP oF various Rerigerant blendsFig.5.2 EER of Various Refrigerant BlendsFig 5.3 :- Variation in COP w.r.t. timeFig 5.3 shows that the variation of COP with time at loading on condition. COP decreases with increase in time.Fig 5.4 :- Variation in EER w.r.t. timeFig 5.4 shows that the variation of EER with time at loading on condition. EER decreases with increase in time.CHAPTER 6. CONCLUSION The problem of R134a (GWP) is identified from the environmental site. Hence an alternative refrigerant is chosen with better COP and EER.Mixing ratio (0:80:20) has higher value of COP Also mixing Ratio (20:60:20) has higher value of COP as compared with other blends and R134a,At loading condition ON.The given Refrigerator with different Refrigerant blends is Four star rated.Mixing refrigerant GWPAnd ODP is lower than R134a. This refrigerant blends ( R32/R600a/R290) is comfortable as working substance in VCR system. Hence mixing Ratio (0:80:20),(10:70:20), (20:60:20),(30:50:20) Having higher value of COP hence This blends can Easily replace R134a in domestic Refrigerator. FUTURE WORKCOP of the Other Refrigerant blends is Slightly lower than Refrigerant R134a because of R32 is lower Refrigerating Effect . Hence in Future use different Hydrocarbon Refrigerants Like R1234yf which is joint venture of Dupont and Honywell, also use different ecofriendly refrigerants with different mixing ratios. REFERENCESK.Mani, International Journal of Thermodynamics (IJoT)-“Development of Statistical Models for Predicting Performance of R12, R134a and R290/R600 Mixture Refrigerants using Design of Experiments”,pp.43-53,2013Mohammad S. Hatamipour, “Exergy analysis and optimization of R600a as a replacement of 134a in a domestic refrigerator system”, (international journal of refrigeration 36 (2013) 123-242)Mujahid Sheikh-“Comparative Analysis of Energy Efficiency Ratio & Electric Power Consumption of Domestic Refrigerator using Refrigerant R134a & R600a at Constant Evaporator Temperature”, (IJSR), ISSN (Online): 2319-7064,2013Rajanikant Y. Mahajan, The International Journal Of Engineering And Science (IJES) – “Performance Evaluation of Domestic Refrigerator Using Hc-12a Refrigerant as an Alternative Refrigerant to R12 And R134a” (Issue 10 – Pages – 26-37, 2014)Gaurav, Raj Kumar. The International Journal Of Engineering And Science-“Performance Analysis of Household Refrigerator with Alternate Refrigerants”, ISSN: 2319-8753Vandana Jatav1 ; R.C.Gupta, Global Journal of Engineering Science and Researches-“Experimental Investigation Of Domestic Refrigerator With Micro channel Condenser Using 134a And Hydrocarbon Refrigerant”, Issn 2348 – 8034,2015Ajoy Bhargav1, Nitin Jaiswal2. IJAET-“Comparative Analysis of R290/R600a with commonly used Refrigerant”, ISSN: 2395-3594R. Cabello, E. Torrella, J. Navarro-Esbri, “Experimental evaluation of a vapour compression plant performance using R134a, RR407C and R22 as working fluids”, Applied Thermal Engineering, Vol. 24, pp. 1905-1917, 2004.K. Senthil Kumar, K. Rajagopal, “Computational and experimental investigation of low ODP and low GWP HCFC-123 and HC-290 refrigerant mixture alternative to CFC-12”, Energy Conversion and Management, Vol. 48, pp. 3053-3062, 2007.B.O.Bolaji, M.A. Akintunde, T.O. Falade, “Comparative analysis of performance of three ozone-friends HFC refrigerants in a vapour compression refrigerator”,Journal of Sustainable Energy and Environment, Vol. 2, pp. 61-64, 2011.Balakrishnanp. ,experimental study of alternative Refrigerants to Replace R134a in a domestic refrigerator. IJRAME,ISSN(online):2321-3051,vol.3 Issue 4.A.S. Dalkilic, S. Wongwises, “A performance of vapour-compression refrigeration system using various alternative refrigerants”, International Communication in Heat and Mass Transfer, Vol. 37, pp. 1340-1349, 2010,.Somchai Wongwises, Nares Chimres, “Experimental study of hydrocarbon mixtures to replace HFC-134a in a domestic refrigerator”, EnergyConversion and Management, Vol. 46, pp. 85-100, 2005.D.V.Raghunatha Reddy , p.Bhramara, “Hydrocarbon Refrigerants mixture as an alternative to R134a in domestic refrigeration system” International Journal of Scientific and Engineering Research, Volume7,Issue 6, June 2016.V.M.Bhatkar, V.M.Kriplani, G.K.Awari, “Alternative Refrigerants in VCR cycle for sustainable envoirnment ” . international journal of envoirnmental science technology, 10:871-880 , 2013.Alka BaniAgrawal and Vipin Shrivastava, “Retrofitting of vapour compression refrigeration trainer by an eco-friendly refrigerant”, IndianJournal of Science and Technology, Vol. 3, No. 4, pp. 455-458, 2010.AkhileshArora and S.C. Kaushik, “Theoretical analysis of a vapour compression referigeratio System with R502, R404A and R57A”,International Journal of Refrigeration, Vol. 31, pp. 998-1005, 2008.Miguel Padilla, RemiRevellin, Jocelyn Bonjour, “Exergy analysis of R413A as a replacement of R12 in a domestic refrigeration system”,Energy Conversion and Management, Vol. 51, pp.2195-2201, 2010.Mohan M. Tayde, Lalit B. Bhuyar, Shashank B. Thakre, Design and Development of Mini-Scale Refrigerator, American International Journal of Research in Science, Technology, Engineering ; Mathematics, ISSN (Print): 2328-3491, 2013.M.A.Ankitunde ,” experimental study of R134a,R406A and R600ablends as alternative to Freon 12.” IOSR Journal of Mechanical engineering, volume 7, Issue 1,May-June 2013.M. A. Sattar, R. Saidur, and H. H. Masjuki, Performance Investigation of Domestic Refrigerator Using Pure Hydrocarbons and Blends of Hydrocarbons as Refrigerants World Academy of Science, Engineering and Technology 2007.A.Baskaran, P.Koshy Mathews, A Performance Comparison of Vapour Compression Refrigeration System Using Eco Friendly Refrigerants OF Low Global Warming Potential, International Journal of Scientific and Research Publications, Volume 2, Issue 9, September 2012.Mohd. Aasim Nazeer Ahmad, Chidanand Mangrulkar, Ehsanullah Khan, Experimental analysis of refrigeratorby replacing conventional HFC refrigerants with hydrocarbons, IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE) e-ISSN: 2278-1684, p-ISSN: 2320-2334.S.Daviran, A.Kasaein , S.Glozari, ” A comparative study on the Performance of HFO-1234yf and HFC-134a as an alternative in automotive air conditioning system.”, Applied thermal engineering 110(2017)1091-1100.M.Mohanraj,” Energy performance analysis of R430a as a possible alternative refrigerant to R134a in a domestic refrigerators” Energy for suistanable Development 17 (2013) 471-476.J.K.Vaghela,” Comparative Evaluation of an automobile air conditioning system using R134a and its alternative refrigerants”, Energyprocedia 109(2017) 153-160.M.Rasti, Seyedfoad, Aghamiri, Mohammad-Sadegh Hatamipour “Energy Efficiency Enhancement of a refrigerator using R436a nd R600a as a alternative refrigerant to R 134a”,International journals of thermal sciences 74 (2013) 86-94.ANNEXURE a) Front view b) Back side viewc) Reading panel Front view d) Reading panel Back side viewFig Actual Experiment Set-upFig Fabrication of Assembly method of ThermocoupleFig. Fabrication of Assembly method of pressure measurement using Bourdon type pressure

CHAPTER 1INTRODUCTION1.1 Background of StudyCrude oil is one of the components in petroleum that is very important to be commercially sold over the world and they are known as non-renewable energy. Crude oil is an unrefined product that is obtained from the refining process and they vary from light to heavy crude oils based on molecular weight (Aldahik et_al., 2017).They are highly composed of hydrogen and carbons. Crude oil obtained from drilling process and formation of different layers of constituents will subsequently occur after drilling process where natural gas was found above crude oil as they are lighter while saline water is the most bottom layer as they are denser than crude oil. Thus, further refining of the crude oil can turn into many new products such as kerosene, diesel and others which can be sold commercially in the market.

Crude oil is one of the major petroleum constituents that can be used almost for all types of manufacturing industries such as fuel for transporting, rubber industries, leather industries and so many more. Crude oil is classified as fossil fuels that obtained from the decomposition of some organic materials back few hundred years although current studies mentioned that their preliminary sources are hydrogen and carbon. The formation of crude oil is from hydrogen and carbon reacted with some organic materials such as blue-algae and planktonic that been submerged under the Earth. The usage of crude oil begins at the 19th in the industrial field even they had been discovered during Industrial Revolution itself to replace coal usage that had been used for many years before by many countries. The demand for the usage of the crude oil increases drastically at the 20th century as the usage of internal combustion engines developed rapidly in many countries especially United States of America(USA).

USA is one of the most top exporters of the crude oil until the 1960s’. Today, as the usage of crude oil plays a vital role in most industries, thus there are many other countries that act as exporters for the crude oil such as Malaysia, India, Iran and many more other countries.1.

2 Problem Statement of StudyThere are many problems arise during the drilling process to produce the crude oil and the main concern or issue that is severely attacking the world of petroleum industries is that the solid deposition in the pipelines during transportation process of crude oil (Energy et al., 2005). Solid deposition here is known as waxes and asphaltenes deposition.

Due to this phenomenon, the production lines can be choked and the production of oil had been disrupted unofficially. This reduction of oil production can cause the economy of Malaysia being disrupted indirectly. The highest molecular weight of n paraffin or known as n alkane with hydrocarbon bonding is one of the main component in wax formation in oils especially in crude oil (Energy et al., 2005).

Asphaltene is one of the components that found in the crude oil and they are known as high molecular polyaromates or called as resin too sometimes. Although wax and asphaltenes act structural stabiliser during formation of crude oil, at certain temperature along the transportation can cause them to turn into large clumps which lead to the deposition process. Due to this high coagulation of wax, blockage will occur in the pipeline due to reducing of space or diameter because of high deposition of precipitations. As a result, cost of maintenance of the industries will increase gradually as the cost to improve the pipeline is too high and need to be maintenance frequently by the management of industries. As prevention is always better than cure, an effective method is devised to prevent any issues formed from the deposition along the pipelines by improving the flow properties of crude oil.

Figure 1.1: The deposition of wax in the pipelines Source: The Role of Temperature in Heavy Organics Deposition from Petroleum Fluids. Retrieved from http://www.mansoori.people.

uic.edu Thus, the main focus of this paper is to reduce the viscosity of the crude oil through using chemical inhibitors using ethylene-vinyl acetate (EVA), MCH and toluene and butanol as the inhibitors.1.

3 Aim of the ResearchPast researches had been done to find the best method to inhibit the wax precipitation along with asphaltene deposition too along the pipelines. The researches are still going for a few years as they still finding the best formulation of chemical inhibitors that can give the most efficient reduction of viscosity and higher solubility of wax and asphaltenes. They also still searching the best optimum conditions to inhibit the wax and asphaltene in a higher percentage of reduction of viscosity in terms of temperature, concentration and shear rate of the inhibitors.

Eventually, each new study that is proposed for this issue always has been guidelines theoretically for a new treatment to be proposed by new researchers. As an example, the past researches helps to determine the basic knowledge on wax and asphaltene molecular structures, inhibitor structures and the relationship between bonding of the asphaltene or wax with the inhibitors and the treatments that had been used before by the past researchers. This knowledge is very important for a better modified new treatment. Actually, these past researches had strong guidelines or foundation to identify the essential compounds or functional groups that can act as inhibitors for the wax and asphaltene inhibition. Indirectly, they help to save time for analysing the types of compounds that should be used and modification of the treatment can be done more efficiently without clashing with the theoretical knowledge of engineering.

Thus, the main aim of the research is to maximise the reduction of viscosity by using the different formulation of the chemical inhibitors and the novelty of this research is by using the combination of different formulation of inhibitors by using different structures of solvent which are aromatic and non-aromatic compounds such as toluene and butanol with, ethylene-vinyl acetate copolymer (EVA) dissolved in methylcyclohexane (MCH).1.4 Objectives of the ResearchAt the end of this research, these objectives should be achieved:i) To differentiate the effect of the aromatic and non-aromatic compounds towards wax and asphaltene solubility.ii) To determine the percentage composition of each chemical, namely, EVA, MCH, butanol and toluene to contribute to the overall inhibitor efficiency.iii)To optimize the percentage composition of inhibitor and optimum temperature of inhibitor using Response Surface Methodology (RSM).1.5 Scope of the WorkThe research study is subjected to several limitations.

The following describes the scope of study in details:i. The study is done by using only one type of ethylene-vinyl acetate (EVA) which is EVA40.ii. The method that been used here to analyse the results is by measuring viscosity by using viscometer.iii. The shear rate and concentration effect on the viscosity are being neglected throughout the research.iv. The data that taken for each sample is at temperature ranges around 5°C to 20°C only.

v. The analysis of these data done based on two different scenarios such as blank crude oil and crude oil with the different formulation of inhibitors.1.6 Significance of the StudyThere are three main contributions of this study.

This study will provide a clear insight into how chemical treatment being conducted to inhibit the deposition in the pipelines. This study will describe the temperature range that will be very suitable for the reduction of viscosity of the crude oil along transportation process. The analysis will be used to find the proper and accurate inhibitors formulations .This study also will explain how different functional groups compounds that can affect the solubility and viscosity of wax and asphaltene in crude oil. Lastly, this study will be beneficial for knowledge to enhance chemical treatment method in future.1.7 Research OutlinesThis study is divided into five chapters. In Chapter 1, the introduction is given about definition of crude oil, history of crude oil and the importance of crude oil for various types of industries.

The problem statement of the current research was stated provide a clear picture of the main concern from the deposition of wax and asphaltene to the flow of crude oil in pipelines. Definite objectives of the planned study are provided which to be achieved at the end of the study and the scope of the study covers the research limitation and works to meet these objectives. Chapter 2 or literature review covers the fundamental of crude oil, characteristics of crude oil, wax and asphaltene characteristics, wax treatment and asphaltene treatment, wax and asphaltene inhibitors . Chapter 3 or experimental methodology describes the steps that were conducted to prepare the chemical inhibitors treatment to study the viscosity of the crude oil. Chapter 4 comprises of results that obtained from the experiment that had been conducted to treat this deposition of wax and asphaltene in crude oil. Finally, Chapter 5 covers the conclusion and recommendation for future work and development. CHAPTER 2LITERATURE REVIEW2.1 Crude OilIn this world that is developing day by day, crude oil has become one of the important natural resources in terms of fossil fuels.

Crude oil is actually one of most necessary resources especially for the industrial field nowadays( Alkhalili et.al, 2017). Due to the development of petroleum industries in the global world, the demands on crude oil production and exploitation increasing gradually every day. The formation of crude oil is about 500 million years and to form crude oil is actually a very slow process as it occurs naturally. The production of oil occurs from thedeposition of sediments naturally especially in bottoms of seas and lakes for approximately thousand and formed a layer of microorganisms, plants and animal (Abdel-Raouf, 2012). The definition of crude oil is based on its chemical composition as they are a mixture that is very complicated where consists of main elements such as carbon and hydrocarbons where hydrocarbons are made of 90% from its overall composition while the derived organics in crude oil are sulphur, nitrogen, oxygen and organometallic. Crude oil can be divided into two types of classes such as hydrocarbons and non-hydrocarbons as shown in figure below Figure 2.

1: The flow chart of formation of crude oil Source: retrieved from http://www.scranton.edu There are three types of crude oils which are light, medium and heavy. They have divided into these three different types due to the compositions of fractions that will derive from refining process(Ezugwu, ; Nwadinigwe, 2016).The higher petroleum demands caused the heavy oils to be used in higher percentage rather than light crude oil. Figure 2.2: The percentage of reserved crude oil Source: retrieved from http://www.bravenewclimate.

com There are four different main classes of hydrocarbon which are saturated as in alkanes and cycloparaffins, aromatics, resins and asphaltenes. Resins are actually fractions that formed by heteroatoms such a nitrogen, oxygen and sulphur while asphaltene is molecules that are heavier than the resins. (Abdel-Raouf, 2012). Figure 2.3: The Percentage of Elements in Hydrocarbons Source: retrieved from http://www.scranton.

edu2.2 Characterization of Crude OilThese heavy crude oils cause many issues along their transportation in the pipelines as heavy crude oil are more viscous and less fluidised type than the light crude oil. The special character of heavy crude oils which makes them has higher viscosity rather than light crude oil is that they have higher oil compositions such as resins, sulphur, and asphaltene.

The main purpose to do SARA composition analysis should be done is to identify and reduce the effect of asphaltene composition to the clogging process in pipelines(Ezugwu, ; Nwadinigwe, 2016).Furthermore when there is the presence of natural surfactants, they play a vital part in reducing the emulsion and stabilised them by lowering the tension that occurs on the interfacial surface of the crude oil(Wen, Zhang, Wang, ; Zhang, 2016).Moreover, heavy crude oils have complicated interactions among different types of oil species which makes them be less fluidised compared than light crude oil (Khan et al.,2017). Another classification of crude oil is based on derived elements which are sulphur and this class is known as non-hydrocarbons crude oil. Crude oil has many types of inorganic sulphur which appears either in form of suspended sulphur or dissolving sulphur itself.

Crude oil can be classified as sweet and sour crude oil other than heavy or light crude oil. This character can be determined from the percentage of sulphur content in the crude oil. The crude oil considered as sweet crude oil if the sulphur is less than 0.5 wt% and if the sulphur is more than 0.5 wt% is known as sour crude oil. Sweet crude oil is more profitable than the sour crude oil and this is because crude oil that contains more sulphur is not environmental friendly.

The organic sulphur in the crude oil comes in two forms which are heterocyclics and non-heterocyclics. There are few types of sulphur in crude oil such as mercaptans, sulphides, disulphides and thiophenes. Mercaptan is known as acidic sulphur as they contain thiol group while non-acidic sulphur is sulphide and thiophenes (Alkhalili et.al, 2017).The aromatic sulphur in described in the diagram below: Figure 2.4: The aromatic compound of sulphur in crude oil Source: Alkhalili et al.

(2017) Crude oil contains mechanical impurities too such as particles of solid. Those particles of solid undergo adsorption process into the oil-water interface which stabilises emulsion of particles. Thus formation of these emulsions will affect the characteristics of flow of crude oil in the pipelines and might cause blockage in the pipelines which currently affecting petroleum industries worldwide especially in Malaysia( Zhang et.al, 2016)2.3 Wax Crude oil is actually a mixture of liquid that comes in a very complicated form. They are absolutely made of hydrocarbons such as waxes and asphaltenes (Ghanbari et.al, 2015).Crude oil has been categorised into three main different categories which are the light, medium and heavy( Nwadinigwe et.

al, 2016). They are divided based on the fractions composition from the refining process of the crude oil(Nwadinigwe et al., 2016). Wax is defined as the ester that is formed from the combination of a long chain of alcohol and fatty acids. This eventually makes them hydrophobic to water where they are resistant to the presence of water. Figure 2.

5: The structure of long chain of wax ester Source: Retrieved from http://www.lipidhome.co.uk They are actually a fraction of the crude oil that has the biggest molecular weight of paraffin and they were affected when the temperature of the oil is below than the pour point of the oil itself. The long ester compounds are being formed after great Paraffin is approximately 20 wt% of the total mixture of hydrocarbon(Patel, Chitte, ; Bharambe, 2016).A complex morphology with in form of the 3-dimensional shape of a compound derived as wax crystals(Energy et al., 2005).

Wax can be divided into many types of different categories based on the chemical structure such as bees wax, carnauba wax from carnauba leaves and many others. The common wax constituents are being shown in the diagram below: Figure 2.6: The structures for some common wax constituents Source: Retrieved from http://www.lipidhome.co.uk Based on the previous research, the lower the oil temperature than the pour point, the easier the wax can be separated from the crude oil. The contents of the paraffin are that they are a mixture of hydrocarbons where comes in many chains around more than 20 carbon attached together in form of alkanes. Wax crystallisation caused precipitation occurs along with phase separation.

Based on Behbahani(2015), the limitation of value to build a stable wax crystals compound is such as 2% w/w and that what called as the wax-oil gel (Behbahani et al., 2015). Wax is being formed from the aggregation process where this process helps to produce bigger wax crystals.

The quantity of the wax will be categorized by the high pour point, high viscosity, strength of the gel and finally the deposition of the wax(Al-sabagh et.al, 2013). If the wax is below the required temperature then they can easily remove out from the crude oil. The crude oil is called as gelated oil or wax when they crystallized themselves by interlocking to each other so indirectly they are increasing the flow resistance(Al-sabagh et al., 2013). Thus an inhibitor is required to prevent the wax crystallisation. The wax crystallisation took shorter time at the wall of the pipeline while longer time at the centre of the pipe.

This is because of the temperature difference between two different points of the pipe. Indirectly, the reduction in temperature causes the pipe to have some blockage or gelation in transporting the wax(Patel et al., 2016). The maximum temperature for a wax to melt is about 62°C based on DSC analysis (Motawie et al., 2015). There are many possible solutions that can be done to transport the wax maybe such as heating the crude oil earlier before releasing them into the pipeline, having a special system to modify the wax, controlling the thermal condition to reduce the effect for the pour point. However based on previous researches, each solution have their own limitations(Patel et al., 2016).

The most economical or best way to overcome the wax precipitation and crystallisation is by using the additives of polymeric chemicals and oil-soluble surfactants(Patel et al., 2016). Wax build-up is the most difficult issues that to be handled in petroleum industries. Wax crystallisation from crude oils can be affected by many parameters such as composition, temperature and pressure of the system(Hosseinipour et.al,2016). The purification of the natural gas from the petroleum industries need a better separation process that caused carbon dioxide content reached 70%(Hosseinipour et al.

, 2016). Wax produced because from the transportation of the crude oils, seabed and the temperature of the surface of the pipe. The main purpose to remove n-paraffin from the crude oils is to obtain less fraction of wax in crude oil.

The wax crystal will attach together to create the crystal in solid and affect the characteristics of the crude oil. Gel emulsion properties can be affected by n-paraffin content and that n-paraffin content can cause waxy crude oils. These highly molecular weights of the paraffin caused the petroleum industries to face a very major problem in their transporting away the crude oil through the pipelines. The transportation of these waxy crude oils should be done above the wax appearance temperature(WAT) to prevent any clogging occurred in the transportation line(Gonza, 2001).When there is disruption on the wax crystal agglomeration, then the formation of the wax will become softer which caused the flow of the crude oil become easier and smoother(Theyab, Diaz, Theyab, ; Diaz, 2017).2.4 Paraffin Wax Characteristics Wax in crude oil also known as paraffin waxes. They were categorised based on their melting point and the limit of degree of refining if they are in macrocystalline waxes.

If they are soft paraffin waxes, then the degree of melting temperature should be less than 45°C while hard paraffin will have higher than 45°C but not more than 60°C. The classification for the refining of paraffin waxes is in three main categories which are refined waxes, technical and finally semi-refined. The content of oil is less than six weight percent (wt %) in technical grade paraffin waxes and they are the products of the slacks through dewaxing process. If the semi refined paraffin waxes, the content of oil will be more than three weight percent (wt%) which shows that they are heavier than the technical paraffin waxes. Usually, the paraffin appearance of semi-refined paraffin waxes will be yellow or in white in colour.

Last but not least, the refined waxes will be colourless and they are less toxic to health and odourless too but they contain the least amount of oil or wax. Classification of paraffin waxes can be divided into two main groups which are the macrocrystalline waxes and microcrystalline waxes. Paraffin waxes are made of more than 25 atoms of saturated hydrocarbons. If they do not have any effect on the properties of wax, then they are macrocrystalline paraffin waxes where they have a number of aromatic ring compounds with less molecular weight. Usually, the most common compound that builds the aromatic rings in paraffin waxes is alkylbenzene.

Figure 2.7: The structure of paraffin waxes Source: Anne (2012)2.5 Wax AdsorptionNowadays in petroleum oil industry, the deposition of wax in the oil-water multiphase transportation line had been a great issue that being attacking the flow of oil in the industries. This is due to the formation of wax-oil in emulsion due to higher adsorption between the surfaces of the wax.

Based on Zheng and Fogler (2015), they mentioned that blocking of the diffusion path occurred due to the wax droplets that formed in the pipelines. There is a study is being conducted currently where the adsorption of natural oil can be classified into two major elements where they focus more on the asphaltene and the wax crystals. From the previous research, the emulsion can be stabilised by adding some fine particles such as crystals of the wax and silica where they are known as picking emulsion. The adsorption of the wax can occur very fast at the interface of the oil-water if the wax had formed co-crystals with the addition of ester or acid molecules together and without the presence of a surfactant. Surfactant sometimes can act as inhibitors to prevent wax deposition in the crude oil too and reduce the wax adsorption on the interface of crude oil. Wax adsorption become more stable if they are in the continuous phase of the emulsion in state oil-wax.(Qianli Ma et al.

, 2017). Moreover, the temperature will also affect the gelation and adsorption of wax where the increase in temperature can cause the adsorption of wax on the interface of crude oil decreases and eventually increase the solubility of wax.Figure 2.8: Adsorption with the presence of surfactant Source: Ma et al. (2017)2.6 Wax TreatmentNext interesting part about wax removal from crude oil is that there is exposure to the traditional experimental method (Aiyejina et.

al, 2011). The methods that they had been explaining here is the direct method such as “take out” and pigging method. When there is a removal of pipe to measure the deposition of the wax, it is called as ‘Take out’ method. There is another new method to calculate the volume of wax by inventing the strain gauge even to detect the smallest change in the wax percentage and the result from this invention was really predictable as expected. The disability to expand the design is that the experiment can only be conducted in laboratory scale to represent the actual system. Another traditional method that had been practised in the new research is by using acrylate polymer, acts as pour point depressant (PPD)which comes in room temperature and it is in solid form polymer(Admiral et al.

, 2016).There are some findings of PPD where PPD were improvised to enhance the ability of a crude oil to flow in the pipeline. The viscosity of traditional acrylate polymer is lower where it comes in solid form than the emulsified acrylate polymer (Admiral et al.

, 2016).They come to a conclusion that the emulsified pour point dispersant is better compared than traditional pour dispersants. Emulsified PD90 can be created when emulsion technique is used to form droplets of PPD (Admiral et al., 2016).Emulsified PD90 shows good result in the reduction of pour point depressant other than the solvent based on PD90. This is because that the content of kinetic energy of emulsified PD90 or inhibitors is higher than the pure PD90 and this caused the molecules of wax move freely around the atoms of crude oil and it eventually inhibits the crystallization of wax (Admiral et al.

, 2016) The deposition of crude oil can be treated with several methods such as developing pressure in the pipeline, applying heating principles and finally coating the pipelines with any materials. The main purpose to increase the pressure is that to have higher shear rate so that the deposition of wax becomes slower than usual. By heating method and coating method, the adhering of wax can be prevented and caused the flow of the crude oil to be smoother. Prevention is always better than cure and prevention is the best decision to solve this current issue in petroleum industries. Reduction of cost for the maintenance of the blocked pipeline together with the replacement of new equipment can be done through prevention or treatment methods. Thus, there are many types of researches still being conducted by some researchers so that they can find the best inhibitors to obtain 100% efficiency in preventing the deposition of wax.2.7 Wax InhibitorsAlthough there are many traditional methods to remove wax precipitation, the most frequent method that is used is the wax inhibitor.

An inhibitor is being categorised as the modifier of the crystals, depressants of the pour point and inhibitors of paraffin followed by the flow improvers(Energy et al., 2005). A wax inhibitor can ensure that the growth of the wax stopped and able to prevent any wax blockage occur in the pipeline (Theyab et al, 2017). They are actually one of the methods to protect the pipelines of crude oil from wax deposition. Figure 2.9: The pipelines in presence and absence of Inhibitors Source: Retrieved from http://www.

drdakin.tripod.com Wax inhibitors are being influenced by many external factors such temperature, concentration and shear rate of the inhibitors themselves. In the past reviews papers, they had to use the high-pressure micro differential scanning calorimeter to measure the curve of the solubility of wax under the Wax Appearance Temperature (WAT).

Some researchers had been conducting further research to identify the new parameter that can control the first formation of wax crystals such as carbon dioxide being studied in one of past researches (Hosseinipour et al., 2016). From one of the results, the Wax Appearance Temperature (WAT) of all crudes oils from Malaysia is above 25°C. This proves that Malaysian crude oils should use the wax inhibitors and Malaysian petroleum industry is not recommended to use single line pipeline due to the value of WAT is too high and the average temperature of the seabed is approximately or more than 25°C. Based on Hoffmann and Amundsen (2013), both of them came in a conclusion that the thickness of the wax can be reduced approximately 60% to 90% when the wax inhibitor being applied in different concentrations when they did their experimental work. In one of the research, the inhibitors that had been used is related to the polymers that classified as pour points depressants to solubilized the wax crystals in the pipelines (Theyab et al., 2017).

Wax is known as a compound that looks like a cage which inhibits the flow of the crude oil(Admiral, Abdullah, ; Ariffin, 2016). Wax can be classified in term of stability based on the particle size of the wax crystals. In the opinion of previous researches, there is still lacking on the studies of the wax deposition in the crude oil.

The justification from all the researches, wax becomes the most important part of the crude oil that need to be removed to ensure a proper flow in the pipelines and reduce the blockage or clogging critical issues. Wax inhibitors should be used for the deposition of wax that occurs in a long run pipelines such below: Figure 2.10: The deposition of wax in the inner surface of pipeline walls.Source: Nanochemistry drives new method for removal and control of wax (Journal of Petroleum Technology)Figure 2.11: The deposit appearance without inhibitors (left), with inhibitor (right) Source: Hoffmann ; Amundsen (2013) In order to maintain the productivity of the crude oil and ensure the flow properties of the crude oil, inhibitors should be introduced for the paraffin or wax deposition in the pipeline (Al-sabagh et al., 2013). In the research done by Amel A Nimer (2009), there are actually two types of methods to ensure the wax to be removed from the surface of the crude oil.

The methods are solvent removal and catalytic removal where solvent removal is the most effective way compared than the catalytic removal (Rabah, 2017).This is because based on the review from the article, solvent removal method can remove the hydrocarbons that come in the heavy form or lighter form while catalytic removal only light hydrocarbons or the carbons that are above the boiling range (Rabah,2017). The researchers of this article had been using toluene and methyl ethyl ketone (MEK) as their inhibitors for solvent removal method. They used toluene in their research experiment because they are the one of the purest solvents which acts as the best removal for any oil surfaces even the wax crystals followed by the usage of methyl ethyl ketone(MEK) as they can precipitates the wax better. There are many frequently used polymers before and they had given some efficient results in inhibiting the wax deposition in crude oil. The common polymers used are such as below: Figure 2.12: Structure of Ethylene/vinyl acetate (left), ethylene/acrylonitrile copolymers(right) Source: Kelland (2009) There are many types of inhibitors that can be used for the removal of wax in the natural oil not only crude oil and the structure for each inhibitors being described as shown in the figure below: Figure 2.

13: The structure of common inhibitors used Source: Madhi et al. (2017) The dewaxing method in terms of solvent requires more energy to be consumed rather than the catalytic waxing especially for the regeneration of the solvent and pumping. Moreover in this study, they proposed that the ratio of the crude oil should be lower than the solvent ratio because increased solvent quantity can solubilised the crystallised form of the wax and the earlier literature shows that the ratio should be in 16:1 or 32:1 in term of mass(Rabah, 2017). In this research, they managed to find the operational conditions for the wax production.

The results are such as to produce wax in a higher amount and it requires 75% MEK, ratio of 20:1 solvent to oil with -17°C in 30 minutes with retention time about approximately 20 minutes. The wax that had been formed from these operational conditions consists of a smaller amount of the 6% of lighter n-paraffins. The justifications form this literature review of this article is that toluene could be replaced with another solvent like butanol or benzene along with the MEK being substituted with Methylcyclohexane (MCH) to obtain different observations for the operational temperature to have a smoother flow of crude oil in pipelines. Based on another article by Muhammad Ali Theyab and Pedro Diaz(2017), chemical addition become one of the methods that can be used to inhibit the deposition of wax (Theyab et al., 2017). They come with an idea to know the results for different inhibitors with the aid of the programmable Rheometer rig.

The wax appearance temperature can be reduced drastically when they add these types wax of inhibitors in their experiments. The inhibitors that used in this experiment actually prevent the formation of wax by merging and absorbing with the wax crystals. They also mentioned that the polymers that contain wax structure can act as an inhibitor to reduce the crystal growth by covering the wax site to form smaller wax.

The temperature where the wax in semi-solid called pour point reducing from 27.6°C to 13.2°C and the viscosity reducing to 52.

5% if the temperature is higher than 5°C( Theyab et al., 2017). One of the past research study mentioned that the flow improvers act as pour point depressants actually makes the crude oil transportation along the pipelines can be done easily(Patel et al., 2016). In this research, the polymers that had been taking part are such as maleic anhydride and n-alkyl oleate which they were tested by the free radical polymerisation. They were tabulated based on the results from the Fourier Transform Infrared Spectroscopy (FITR) and the Gel Permeation Chromatography.

The results were based on the apparent viscosity, plastic viscosity and finally the yield value. As a conclusion, the results of the apparent viscosity, the yield value and the viscosity of the plastic reduce to the most appropriate values for the crude oil that is virgin(Patel et al., 2016).

Another literature review that had been proposed for this topic is that investigation on the behaviour of the crude oil in term of rheological with or without the inhibitors or known as pour point depressants (PPD). The polymer that had been used in this experiment is that ethylene vinyl acetate (EVA) polymer. They used Iranian waxy crude oil as the sample for this experimental purpose. The polymers used based on different characterisation based on the content of nitrogen, the content of carbon and hydrogen followed by various molecular weight of the polymer to enable getting various results at the end of the experiment (Behbahani et al., 2015). At the end of the experiment, the result of the viscosity is dependent on two parameters which are shear rate and the temperature of the inhibitors.

The formation of the gel network actually boosted up the viscosity of the crude oil and those gels had been formed in the experiment when the temperature of the wax reduced in between 5°C and 30°C. These inhibitors for wax functions as a modifier of the structure of the wax chemically where the reduction in the growth of wax crystals occurred in the pipelines of crude oil. Although there were many types of researches that had been done before for these inhibitors method, the only drawback that had been suggested by them from this method is that the inhibitors only can reduce the growth of the paraffin waxes but still do not fully stopped the deposition process of wax in crude oil which may lead to a continuous deposition process along the flow of crude oil in the pipelines (Anisuzzaman et al., 2017).

2.8 Asphaltene in Crude OilOne of the constituents in the crude oil other than wax is asphaltene which can cause deposition and leads to blockage of pipelines in petroleum industries. Asphaltenes are known as impure compounds as they consist thousands of different species with different molecular weights but similar behaviours chemically(Wei et_al, 2016). Their nature is actually very complicated and complex which makes the study of their characteristics becomes harder(Rocha et_al,2006). Asphaltenes have higher solubility in the non-polar solvent such as toluene and they are not soluble in the polar solvents such as glycerine, water, n-heptane and n-pentane compounds(Adebiyi ; Thoss, 2014). Moreover, asphaltenes always exist in suspended solid form or known as colloidal particles and the structures of the asphalthenes being interconnected by bridges that are formed from some aromatic compounds as sulphur or alkyl(Zhang et al., 2014). The existence of aliphatic or aromatic chains caused them to be one of the heaviest elements in the crude oil.

Figure 2.14: The illustration of asphaltenes structures by SpeightSource: Petroleum Science and Technology 25(1-2):67-80(2007)Table 2.1: The composition of asphaltenes that derived from four different countries Source: The Chemistry and Technology of Petroleum (Speight, 1999).2.9 Asphaltene TreatmentBefore analysing the asphaltene treatments, the needs to differentiate between three common terms that will be frequently used which are precipitation, flocculation and finally deposition is very important. Precipitation is a process that forms particles in semi-solid through aggregation process and usually, they are in one-micrometre size particles. After a big cluster of precipitate is formed, then they are known as flocculate and this is so called as flocculation process. Finally, deposition is the last stage process that forms the blockage in pipelines due to heavy or large adsorbed particles on the surface of the pipelines(Shadman et_al, 2017).

Deposition of asphaltene occurs due to its stability and the deposition always occurs at many target places along the pipelines such as inside the pumps, valves, and flow lines of the pipes(Adebiyi ; Thoss, 2014).Based on Kokal and Sayegh(1995), they mentioned that the deposition or precipitation of the asphaltene occurred due to many reasons such as temperature changes, the composition of the chemicals themselves, chemical properties due to the mixture of oil and other substances. These depositions caused a severe problem in terms of transport and process facilities in petroleum industries almost all over the world. Thus, there are many types of treatments that can be done to overcome the precipitation of asphaltene in crude oil. The treatments or methods that had been used by many types of previous researches are such as mechanical removal, ultrasonic removal, removing the deposition by using any high temperature or hot fluids such as water steam, and finally adding the inhibitors or other types of dispersants that can breaks the structure of the asphaltene and prevent them from growing bigger to form a precipitate (Rocha et al., 2006).

Based on Shadman (2017), he introduced a treatment that can inhibit the deposition of asphaltene by using the viscometer by using various types of amphiphiles. The result of the treatment is that the stability of asphaltene is affected by the concentration of amphiphiles and when the concentration increases, eventually the stability increases too. Although there are many treatments or method applied to inhibit the asphaltene deposition, the most efficient treatment is by using chemical inhibitors.2.10 Asphaltene InhibitorsAs mentioned before, the best treatment is by using chemical inhibitors to reduce the blockage in the pipelines due to the asphaltene deposition.

Thus, solvent treatment becomes the best treatment to treat this issue and the most common solvents that can be used as inhibitors are such as toluene, benzene and xylene which they are aromatic compounds. Treatment by using these chemical solvent can saves the cost as well as acts a preventive method for this critical issue. Usually, the inhibitors used to reduce the effect of this problem should be used on a large quantity of crude oil as then the inhibitors can dissolve in a solution that is highly concentrated. Based on Muhammad Ali Karambeigi (2016), he mentioned that the most effective inhibitor that he had used for the Iranian crude oil is IR95 inhibitor with 34% asphaltene reduction in precipitation compared to others tested inhibitors(Karambeigi et_al,2016). This is because IR95 has higher polarity and they are in aromatic form compounds which make the asphaltene to dissolve easily and improved the flow of crude oil. The purpose of chemical inhibitors which have different functional groups and structures is to delay the formation of asphaltene deposition by increasing adsorption to the surface of the asphaltene. Based on the Cenergy(2001), the treatment that had frequently used is by direct injection process into the asphaltene deposition and they are known as a physical-chemical process. The relationship between Van der Waals and electrostatic force between inhibitor increases the adsorption process to the surface of the crude oil.

Based on Chang and Fogler (1994), the concentration of amphiphiles as inhibitor will affect the stabilisation of asphaltenes. When increasing the amphiphiles’ heads, then bonding between the asphaltene and amphiphiles becomes stronger due to higher polarity. This proves that chemical inhibitor such as alkanes improvised the flow of the crude oil in the pipelines by modifying the bonding between the molecules in asphaltene so that they become more stable.

Rogel(2010) mentioned that the reduction in asphatene sizes does not change when the inhibitor had reached the maximum or optimum concentration value and this shows that the concentration of inhibitor plays a role in inhibiting the deposition other than the temperature of the inhibitors with crude oil. The end result of this inhibition process will be more efficient if using cationic inhibitors. Cationic inhibitors can speed up neutralisation of asphaltenes’ polarity and caused them to be easily reacted with non-polar substances eventually fasten up the reduction of the deposition process in the crude oil. Most of the chemical inhibitors can react well at the temperature around 10°C and if their concentration range is about from 500ppm to 5000 ppm. Thus, it is very important in choosing the proper chemical inhibitors with accurate structural functional groups to treat asphaltene issues in petroleum pipelines so that this issue can be solved easily with less costing (Ridzuan et_al, 2016).Table 2.2: The degree of inhibition in percentage for various types of inhibitors at 5°CType of inhibitor Percentage inhibition efficiency (%)Blank crude oil NAAcetone 23.2Toluene 25.

4Cyclohexane 28.9DEA 17.6C-DEA 5.6EVA 36.6MA 32.4Source: Evaluation of the inhibitor selection on wax deposition for Malaysian crude oil (2016)2.

11 SummaryIn a summary for all types of researches that had been studied, the most common used treatment is inhibitors method which is very high-cost saving and the latest technology for this method is that by using the different formulation of inhibitors where it can help to reduce the precipitation of both major components in crude oil which is wax and asphaltenes. Most of the studies, they had been using the ethylene vinyl acetate (EVA) as the major inhibitor with some aromatic compounds such as toluene and xylene which speed up the reaction faster. These combinations of two different compounds such as EVA and xylene really gives the best results and EVA 30 gives better end result rather than other EVA. The presences of Methyl Ethyl Ketone (MEK) at 75% fasten up the inhibition process if MEK is added together with another solvent as EVA and any other aromatic compounds. Moreover, from the previous studies, there are many parameters that had been analysed for the solubility of wax and asphaltenes. The parameters are such as temperature, carbon dioxide concentration, the concentration of the inhibitors and shear rate of the concentration. Based on the previous researches, the optimum temperature or the wax appearance temperature (WAT) is between 11 to 25°C and to reduce the viscosity, the temperature of inhibitors should be increased.

The shear rate that been used for the most of the studies is around 800ppm to 1000 ppm but it is influenced by the concentration of the asphaltene in the crude oil. The summary of the articles that been studies had been done in a form of a table as below: No. Method/Technology Results/Description References1 Thin layer chromatography flame-ionization(TLC-FID) which is high-liquid performance chromotography If pour point is below the environment temperature, there will be higher formation of gel in the form of matrix. The WAT is 41?C based on the TLC-FID. The viscosity and pour points differs for each crude oils and wax represents the n paraffin content. The viscous of the crude oil depends on the n paraffin. The fluid will achieve equilibrium with proper temperature whenever there are long shutdowns. “Flow Assurance Study for Waxy Crude Oil”, Marcia et al.

(2011)2 Chemical addition by adding chemical polymers The WAT temperature is based on 27.6?C to 11?C and WAT can be reduced together with pour-point as there are growing of polyacrylate and acrylated monomer at the edge of crystals due to the addition of phenol aromatic naphtha. The inhibitors will affect the viscosity of the crude oil by increasing monomersby preventing wax crystals to be formed.

“Experimental Study on the Effect of Inhibitors on Wax Deposition”, Muhamad Ali Theyab and Pedro Diaz (2016)3 Solvent extraction The line of isotherm reaches the asymptote at the time of 20 minutes which gives the maximum yield of wax. The temperature increases with wax yield because there is a decrease in viscosity due to the heating process and caused the rate of distribution of solvent in the mixture. As crystal growth being prevented by presence of solvent so the more solvent used to oil ratio can reduce the growth. Indirectly the viscosity of the mixture will reduce but still there are no changes if the ratio of solvent to oil is is 20:1.Moreover, in this literature done by the researcher, the pure Methyl Ethyl Ketone (MEK) can cause the formation of the third phase where there is a new phase to be formed and there are some molecules formed to clogs the filter and reduce the rate of filtration which directs to blockage of waxy crude oils in pipelines. “Wax Separation using MEK Toluene Mixtures”, Amel A Nimer et al.

(2009)4 Differential Scanning Calorimetry Technique (DSC) which is thermoanalytical Technique based on temperature and heat The rate of wax formation is affected by the one of the parameters which is temperature. They have tendency to crystallise the wax if the temperature is below the solid liquid equilibrium temperature. They have stronger effect to the Wax Appearance Temperature (WAT) where they have the shorter hydrocarbon chains. If the temperature is lower than WAT, then they are able to form waxy crude oils. This is because nucleation process occurs here to make nuclei to be more stable. Moreover the increasement in carbon dioxide causes the WAT to be decreased.

In this research they had used the light ends of crude oil where they have huge capabilities to act as a flow improver for the waxy crude oils transportation. WAT in crude oils really helps us to ensure awareness on safe inhibition for the formation of wax and enable smoother flow in the pipelines. “The Effect of CO2 on WAT Crude Oils”, Arya et al. (2016)5 SPSS technology software for analytical purposes The wax deposition is being affected by the crude oil temperature and they increases until the maximum range of temperature which is 38°C. Insulation layer thickness also affects the deposition of wax and it decreases with increasement of temperature. The suitable temperature during 3°C in winter and 15°C in summer and if there is no insulation layer then the thickness of wax is large.

The deposition of wax outside the insulated is thicker and obvious rather than wax deposition inside the insulated pipeline. “Prediction of Wax Deposition in An Insulation Pipeline”, Z. Hu et al.

(2015)6 Acid-catalysed esterification where reaction of alcohol and acid In this research, the best flow improver occurs at higher concentrations where they act as the most effective pour point depressant. The viscosity and the yield value of virgin crude oil will be reduce by flow improver from oleic acid. Wax growth inhibited by oleic acid to improve the flow due to increase in alkyl chain length. This is because of polar part helps to block wax growth. “Oleic Acid Based Polymeric Flow Improves in Laghnaj”, Mayur et al. (2015)7 Chemical Addition and Artificial Neural Network (ANN) where analysed basedcomputational model Shear rate decreases the wax formation by affecting the viscosity of the wax crude oil and it had been reduced to 780 cp from 2250 cp. If it is below the pour point, solid crude oil will be formed where the viscosity will increase.

Viscosity is being affected by temperature and shear rate where if temperature and shear rate increases can cause the viscosity to decrease. At 30°C there is no effect from the improvers to reduce the wax deposition. The factors that affect the flow improvers are the concentrations and the types of of flow improvers themselves. If the temperature is below the pour point depressant, the viscosity reduces because there is formation of paraffin crystals. Moreover, in this study they found that higher molecular weight of flow improvers has higher efficiency for wax inhibition by affecting pour point and the rheological behaviour.

The Artificial Neural Network (ANN) model gives better results than Solid Solution (SS) model as they do not involve wax critical properties. Artificial Neural Network (ANN) method gives better results than Solid Solution (SS) model. “Investigation on Wax Precipitation in Crude Oil”, Tarareh et al. (2015) 8 Commercially available wax inhibitor chemical addition The precipitation of wax will occur at 25 °C and the purpose of wax inhibitor is to change the rheological behaviour of the wax itself. When the experiments done at 23°C, at 125 ppm the thickness of the wax had been observed to have a very obvious reduction until 70% for uninsulated layer while to 90% for insulated layer. At 250 ppm, there is no significant decrease in wax deposition at this temperature. It just had been decrease about 10% from the deposition of wax 125ppm.

At 20°C the wax deposition is pretty higher than the wax deposition at23°C. If the temperature is below than 23°C, 250 ppm of inhibitor does not affect the wax inhibitor as there are no changes with the wax deposition but only 500 ppm is eligible at this lower temperature. If the temperature below than 23?C for 250 ppm of an inhibitor has no effect on wax depositor but for 125 ppm, it reduces to 70%.

“Influence of Wax Inhibitor on Fluid and Deposit Properties”, Hoffman et al. (2013)9 Magnetic treatment by using sintered magnets such as MQII and LDC magnet Sedimentation and wax formation lower at temperature 2?C to 3?C compared to other temperature at 0.1 kg/m2 per hour.

“Influence of Processing Conditions on Sedimentation Kinetics of Highly Waxy Crude Oil”, Y.V. Loskutova et al. (2015)10 Polarized Light Microscopy (PLM) by using optical microscopy tecnhiques A higher driving force or light intensity required to build higher asphaltene molecules. “Effect of Asphaltenes on Crude Oil Wax”, Pavel Kriz and Simon I. Andesen (2004)11 Asphaltene Stabiliser and Solid Detection System(SDS) where it is a PVT cell with a piston floats and attached to an impeller works magnetically The samples characterised by their stability through SARA test and the results shows that the higher aromatic compounds has the best inhibition efficiency to asphaltenes.

‘Effect on Inhibitors on asphaltene precipitation for Marrat Kuwaiti Reservoirs'( Ghloum et.al, 2010)12 Physical MCR 301,apparatus attached with rheometer that rotate together with attached cone and plate The results is if the solvent used has parameter of solubility less than 16.5 Mpa, then the solvent considered as the best inhibitor for the asphaltene precipitation in the crude oil. ‘Asphaltene in Heavy Crude Oil'( Sergey et al., 2017)13 SARA test to separate the crude oil based on its solubility From this research, they obtained that the salicylic acids is the best inhibitors and they also come to a conclusion that the higher polar and aromatic compounds reduce the precipitation of asphaltene better than other compounds. ‘ Experimental Evaluation of Asphaltene Inhibitors Selection for the Standard and Reservoirs'(Karambeigi et al.,2016)14 IR spectrometer to analyse the compounds structure in crude oil The result showed that the asphaltene formation in crude oil is due to the higher content of porphyrins and heterogeneous compounds. ‘Organic Elemental Elucidation of Asphaltene Fraction Nigerial'(Adebiyi ; Thoss, 2014)15 Varian 400 NMR spectrum to determine structure of molecule The research proved that the phenolic aromatic compounds seems removed higher amount of asphaltene compared to other compounds which they only contain 1.

22 intensity of asphaltene in the final product. ‘Characterisation of Asphaltene Extracted from the Indonesian Oil Sand Using NMR,DEPT and MACDI'(Zheng et al., 2015)16 UV Visible Spectrometry Shidmanzu Class Vp Version 6.13 SP2 software to analyse the solubility Dodecyl benzene sulfonic acid (DBSA) and BisACII act as asphaltene inhibitor. The final result is determined by the wavelength of the inhibitors and the software which shows that BisACII in mixture of xylene or toluene can reduce the asphaltene inhibition better than DBSA. An ITC Study of Interaction and Complexation of Asphaltene Model Compounds in a polar solvent II'(Wei et al., 2016)17 Chemical Inhibitors such as toluene,n-heptane and n-hexane The efficiency of asphaltene increases with chemical inhibitors with addition of some organic acids.

Moreover, it is proven that the aromatic compound toluene has better inhibitor characteristics rather than aliphatic compounds. ‘Inhibition of Asphlatene Precipitation in Brazilian Crude Oil using New Oil Soluble Amphiphiles'(Junior et al.,2005)18 Transmission of Electron Microscope to view the morphology structure of asphaltene to determine the end deposit. The result concluded that the larger polarity of C7 in toluene and n-hexane solution decreases the solubility of apshaltene and found that the deposition of asphatene is less than other carbon through microscope.

‘Study on the Polarity, Solubility and Stacking Characteristics of Asphaltene(Zhang et al.,2014)19 Brookfield DV-II and programmable viscometer, FTIR and H-NMR spectrocopy The result is the copolymer which has average molecular weight, higher index of polydispersity and higher amount of nitrogen affect the pour point efficiently which eventually decreases the concentration of inhibitors. The viscosity decreases as temperature increases as 7.29 mPa at 39°C, 190.95 mPa at 27°C and 358mPa at 15°C.

‘Synthesis of Phthalimide and Succimide copolymers and their Evaluation as Flow Improvers for an Egyptian Waxy Crude Oil'(Al-Sabagh et al.,2013)20 SPSS software to determine the equation for wax deposition rate The wax deposition rate increases when the insulated layer of the pipelines becomes thicker and temperature decreases. ‘Prediction of wax Deposition in an Insulation Crude Oil Pipelines’Hu et al.(2015)2.12 Limitations of Literature ReviewAfter many researches that had been studied, the limitations that had been found from the review of all previous articles that there had no justifications done on viscosity of crude oil based on effect of aromatic and non-aromatic compounds on various temperature and form different inhibitors which are EVA,MEK and toluene or butanol. They only managed to come with a result for the aromatic compound formulations but not yet with the non-aromatic compounds.

So eventually,this proves that there had been a small space between all these previous researches where the researchers had been neglected the effect of combination of inhibitors with aromatic compounds and non-aromatic compounds in different temperature ranges. Thus, using the different combination of inhibitors can help to do better comparison on solubility of the wax and asphaltene and together with the viscosity of the crude oil. CHAPTER 3METHODOLOGY3.

1 IntroductionIn this chapter, there are some aspects being described such as experimental setup, the procedures to conduct the experiment and analysis method. In this experiment, the main sample that being used is crude oil which is about 20g of crude oil and the crude oil is being tested for the viscosity and the wax appearance temperature (WAT) at vary temperature from 5°C to 20°C where the interval between each temperature is about 5°C. The result of the tested samples been analyzed by comparing with the properties of WAT of crude oil and the viscosity of crude oil. The data is being tabulated in manually form by plotting graph and Research Surface Methodology (RSM).

3.2 Experimental Setup3.2.1 Materials and ChemicalsThe main material that was used in this experiment is the crude oil that is obtained from Sabah, Malaysia. Thus, the type of crude oil is known as Malaysian crude oil where they contain higher fractions of asphaltene compared to the wax fraction. The wax inhibitor that had been using is ethylene vinyl acetate (EVA). EVA is a type of polymer that can increase adhesion process to the surface of wax molecules. Thus, the size of the wax particles can be prevented from growing and forming a big structure of crystals that can cause heavy deposition.

EVA that been used in this experiment is EVA with 40% wt vinyl acetate. This is because past researchers commonly used EVA 32%wt and 40wt% and the availability of EVA 40wt% is higher than the others EVA. Figure 3.1: The type of EVA that used for this experiment The used solvent for the EVA for this experiment is Methylcyclohexane (MCH).

The melting point of EVA40 is at around 46-47.5?. Thus to ensure EVA fully dissolved in the organic solvent as the reaction occurs at very high temperature, the boiling point of the organic solvent should be more than the melting point of the EVA. So, MCH is the one of suitable organic material as they have a higher boiling point which is at 84°C. Figure 3.

2: The Methylcyclohexane (MCH) used in this experiment The most appropriate inhibitor forasphaltene is toluene but in this experiment, butanol is actually used together so that the comparison of the aromatic and non-aromatic compounds can be studied on the effect on viscosity and the WAT temperature. These types of solvents were used to decrease the formation of crystals of asphaltene and increase the adhesion process to the surface of the asphaltene so that flocculation was prevented on the surface of the crude oil.3.2.2 EquipmentThe main equipment is viscometer and they play a vital role in this experiment results. The viscometer is used to obtain the results for the viscosity of the crude oil samples that are being mixed with the different formulation of inhibitors.

The viscometer used is the Brookfield Programmable Viscometer DV-II + PRO. The standard settings of the equipment are as below.Table 1.1: Standard settings of viscometerSpindle Size 63Rotational Speed 100 rpmUnits cgs The proper method to obtain accurate reading ensures that the viscometer is auto-zeroed before testing the new samples and at different temperature intervals. The viscometer should be left around 10 minutes before using them as a pre-warm up for the device so accurate readings can be obtained at the end of the experiment. The spindle for the viscometer should be handled carefully because it is very sensitive and can break if being handled carelessly beside ensure the calibration of the crude oil is not affected. Figure 3.3: The DVII + Pro viscometer used to measure viscosity.

The next equipment used is Binder Oven. This oven is used to heat the crude oil pre-night until they reach 90°C before mixing with the inhibitors the next day. Figure 3.4: Diagram of Binder Oven for heating the crude oil The function of hot plate stirrer in this experiment is to provide a temperature of 70 -90? during the mixing of EVA, MCH and toluene and butanol, and also during the mixing process of crude oil and the different formulation of inhibitors.

Figure 3.5: The cimarec hot plate stirrer The important equipment that was used in this experiment is water bath. The role of the water bath is to decrease the temperature of the samples gradually as intervals around 5°C between the two temperatures and the temperature range is between 5°C and 20°C during the experiments.

The type of thermometer used to measure the temperature of the samples is digital temperature. Figure 3.6: Water bath used to control temperature intervals A mass balance is used to measure the weight of EVA which is around 20 g so that a more accurate weight of EVA is obtained.

The digital micropipette is used to obtain the accurate readings for the solvents that come in liquid form. Figure 3.7: The micropipette used for liquid solvents3.3 Pre-experimental Preparation of Chemicals and Crude OilThe pre-step for the experiment is that the crude oil is heated in the Binder oven at the temperature about 90? for an overnight.

This step is to melt any deposition of wax crystals that had been formed earlier and the structure of asphaltene that being agglomerates in the crude oil. The preliminary step before this experiment being conducted is the apparatus that will be using such as the spindle of viscometer, measuring cylinder and pipette were heated to 60? so that the precipitation of wax and asphaltene at the point of contact between the hot crude oil and cold apparatus can be avoided and to obtain accurate results. Before mixing of the inhibitor together EVA, MCH and toluene or butanol are heated in a water bath to increase the temperature to 60?.3.4 Preparation of inhibitorThe inhibitors were prepared by conducting them on a hot plate at a temperature of about 90?. Instead of using the oven, using hot plate can help to save time and space for the experiment to be conducted as the limitation of lab equipments in preparing the chemicals. The individual chemicals, EVA, MCH and Toluene are measured separately of its respective volume and weight in accordance with the manipulated percentage composition.

The unit for the EVA is grams of mass while MCH is in mL and toluene and butanol in mL. The total volume of inhibitor used is 0.4g. Thus, for example, if the percentage composition of the samples prepared are 50% EVA, 10% MCH and 40% Toluene, then 0.2 g EVA is measured using a mass balance, 0.04 mL of MCH is measured using a micropipette and 0.16 mL of Toluene is measured using a micropipette. The precaution step here is to replace the tube for the micropipette for each new sample that was taken so that contamination can be avoided and accuracy of the results obtained can be improvised .

Care is taken to replace the micropipette tube for both chemicals to avoid contamination. The purpose of the reaction to be in high temperature which is 90 °C is to ensure that the EVA pellets is completely melted in the inhibitors. After complete melting of EVA occurred, then the crude oil that were placed in the oven overnight should be mixed with the EVA and the inhibitor solutions. If the crude oil is placed overnight, then complete dissolved wax crystal will obtained at the next day. Later, the samples obtained should be shaken around 30 seconds or around a minute. This is to ensure the crude oil and the inhibitors completely mixed.

Then, the samples are placed again in the oven for 15 minutes to allow the reaction to take place. Figure 3.8: The prepared samples with labels Figure 3.9: The samples heated in the oven prior3.5 Experimental ProcedureThe samples prepared were tested for viscosity by using viscometer. Moreover, in this experiment, the samples were tested for the optimum temperature for the efficient reduction of wax and asphaltene appearance on the surface of the crude oil. The viscosity of the samples was taken from the temperature range from 5° C and 20° C with each every 5? intervals. The control sample in this experiment is blank crude oil that is free from inhibitors. The viscosity of the blank crude oil is measured after taken from the oven at room temperature. The temperature of the sample is observed by using the digital thermometer and the decrease in temperature gradually is observed carefully. The step is repeated at every 5? interval until the sample temperature drops exactly to 5?.The sample is immersed in an iced water bath so that the temperature can reduce to the expected temperature. The precaution step here is during handling the spindle of the viscometer and the temperature reading should be taken in eye meniscus level to avoid parallax error in readings. The procedure is repeated for each of the other samples that contain the different formulation of inhibitors with various percent of the composition of solvents and polymers. Before starting a new sample each time, the spindle and temperature probe is lightly cleaned to avoid contamination of the samples.

CHAPTER 1 INTRODUCTION 1.1 General Rigid plastic foams were developed by BASF in 1950 which have been consistently used in building construction (BASF, 1990) and in various geotechnical applications such as pavements (BASF, 1991; 1993), embankments (BASF, 1995) since 1960s. However, it has been proposed to consider as a geosynthetics material under a new product category called “Geofoam? (Horvath, 1991). Other names used previously in geotechnical literature when referring to such materials include geoblock, geoboard, geoinclusion and geosolid. In India, the application of such material in various fields was introduced by BASF (2004). 1.2 EPS geofoam material Expanded polystyrene (EPS) geofoam is a cellular geosynthetic material used worldwide due to its large number of applications. Here is a brief outline about EPS geofoam material.

Since the early 1990?s, geofoam has been generic term for any synthetic geomaterial created in expansion process using a gas (blowing agent) and resulting in a texture of numerous closed cells. Therefore, geofoam is not just one material or product but a very diverse family of many different kinds of materials and products. Expanded Polystyrene (EPS) geofoam is a cellular plastic material. It is a lightweight material usually in the form of block. The commonly used parameter for EPS geofoam is density. The density of EPS geofoam is very less compared to other conventional fill materials used in the foundation practice.

Materials – Several proven geofoam materials exist. There are additional materials which have been tried over the years but were found to be technically unacceptable. Geofoam materials can be divided into three major categories: 1. Polymeric (plastic), 2. Cementitious (typically using Portland cement) and 3.

Cellular glass2 The polymeric category is further subdivided depending on the polymer chemistry and specific manufacturing process used: ? Rigid cellular polystyrene (RCPS), which can be either expanded polystyrene (EPS) or extruded polystyrene (XPS) ? Polyethylene (PE) ? Polyethylene-polystyrene (PE-PS) blend and ? Polyurethane (PUR) Despite the relatively large number and variety of geofoam materials, as a result of more than 40 years of in-ground experience EPS geofoam has emerged worldwide as a material of choice in most applications. Product – Geofoam that can only be manufactured in a factory (which includes the dominant EPS) are typically moulded or cut into the final block or panel shape required for the particular application. However, field cutting of a block or panel to accommodate a particular construction situation can easily be done using a variety of tools. Geofoams such as PUR or FPCC that are foamed in place simply fill the shape of the volume that panel is to be filled. 1.3 Advantages 1 Compared to conventional fill materials EPS geofoam is almost 100 times lighter. 2 Any shape of required dimension can be prepared.

3 It is moisture resistant, possesses negligible capillarity. 4 Excellent compatibility with other construction materials such as concrete and steel. 5 EPS geofoam blocks are easy to assemble, placed and do not require skilled labour which leads to saving in cost as well as time. 6 It has high resistance against growth of bacteria, fungus and insects.

7 It does not interfere with ground water table.3 1.4 Applications 1 Slope stability 2 Embankment 3 Retaining wall 4 Bridge abutment 5 Pavements 1.5 Organization of the report The material contained in this thesis is presented as six chapters.

A review of the previous literature published on fly ash in combination with other material and its uses in geotechnical application and the research needs in present in Chapter (2). The various materials and their characteristics used in the proposed work for the development of EPGM material for sustainable construction are described in Chapter (3). The basic consideration in the planning of experimental program and detailed scheme of proposed investigation are presented in Chapter (4). Development and characteristics of EPGM material is demonstrated in Chapter (3). The data obtained from the experimental investigation is analyzed and interpreted in Chapter (5). The dissertation concludes with Chapter (6), which highlights the importance of the work and enlists the broad conclusions derived from the study conducted.

This is followed by the presentation of topics for future research. Construction of roadway or railway embankments on soft foundation soil such as marine clay is always a major issue due to poor load carrying capacity and excessive settlements. In such conditions, two major remedies are available. One is ground improvement technique by enhancing the engineering properties of foundation soil and second is reduction in the overburden pressure of structure on foundation soil this kind of study can overcome such kind of problems.

Considering first remedial measure as a ground improvement technique, enhancing the engineering properties of foundation soil and its strengthening may be very difficult due to certain reasons such as differing in soil strata or soil strata may not be known accurately. However, second remedial measure is to reduce the4 overburden pressure on foundation soil by using expanded polystyrene (EPS) geomaterial having well defined properties and it can noticeably reduce the overburden pressure on foundation soil due to its very low density. The application of EPS geofoam in geotechnical engineering structures have been given by several researchers, especially in the construction of embankments and pavements (e.g. Frydenlund and Aaboe, 1994; Chang, 1994; Duskov, 1997a; 1997b; Beinbrench and Hillmann, 1997; Duskov and Scarps, 1997; Perrier, 1997; Zou et al.

, 2000; Stark et al., 2004;; Horvath, 2008; Arellano and Stark, 2009; Newman et al., 2010), centrifuge modeling of EPS geofoam embankments Mandal and Nimbalkar (2000), slope stability analysis (e.g. Jutkofsky et al., 2000; Mandal and Nimbalkar, 2004; Akay et al.

, 2013). From the available literature, it is found that most of the work has been carried out in the direction of actual application of EPS geofoam in the field and a very little attention has been given towards experimental investigation especially towards EPS geomaterial in roadway embankments, filling material behind retaining walls and bridge abutments, for backfilling of pipeline trenches and for irregular areas. Therefore, an initiative has been taken to study the small scale model testing of EPS geomaterial for roadway embankments, filling material behind retaining walls and bridge abutments, for backfilling of pipeline trenches and for irregular area fillings.CHAPTER – 2 LITERATURE REVIEW 2.1 General This chapter presents the overview of various constraints associated with the disposal Fly-ash and its uses in civil engineering are hereby identified. Also the fly ash, its physical properties and general uses in various applications is viewed. However, this lightweight geomaterial technology has not yet found its place in geotechnical construction practice in our country. In order to make this technology more relevant and use to, technically sound and cost effective in the present scenario in India, an effort is made to develop a new EPS beads based lightweight geomaterial (LWGM) of desired characteristics for its use in embankments over compressible soils, for reduction in earth pressures in soil retention structures and as backfilling material.

The paper presents the investigations carried out in this respect and the outcome thereof. Keeping in view the above objective, this study represents the information regarding use and application of fly ash based light weight material, stabilized with small percentage of cement, their properties and uses in a most concise, compact and to the point manner. Waste materials utilization is not only the promising solutions for disposal problem, but also saves construction cost of the project to a limit.

The main objective is to investigate the potential of using light weight materials in the field of geotechnical engineering. While studying various relevant literatures, various important facts about Fly ash are realized but various important information about the light weight material is not realized. There is lack of information about the use and behavior of fly ash as a backfill material. This study, therefore, seeks to fill this gap. The present Chapter reviews the attempts made by several researchers to understand the behavior of expanded polystyrene (EPS) material as a construction material to minimize the degradation to a level consistent with sustainable development is reviewed; its procedures and design technologies adopted are studied.6 Literature reviewed in the present Chapter reveals many studies on the application of geomaterial in various Civil engineering projects which are important to contribute the gain of experience and accuracy in framing the future work.

2.2 Advantages of EPGM material as a sustainable backfill material Nowadays, EPGM is an atypical backfill material, but has a number of qualities that makes it stand out from other material. Here are its main attributes. ? It is very good fire resistant. ? Light in weight, easily manageable on site. ? Has comparative high strength. ? Can be used in Construction over the soft soil having low bearing capacity.

? Can be used in low lying areas. ? Can be used to reduce the over burden pressure and to economize structures like retaining wall and embankments, for reduction in earth pressures in soil retention structures and as backfilling material. ? It can be used as a substitute of EPS block geofoams. 2.3 Literature Review Lightweight geomaterials using EPS beads Tsuchida et al. (2001) carried out a series of unconfined compression tests on geomaterial prepared with expanded polystyrene beads, dredged bay mud and cement. The engineering properties of geomaterial developed mainly include modulus of elasticity, compressive strength, and deformation characteristics were studied.

The experimental investigation showed that the secant modulus of geomaterial increases 150-400 times the shear strength obtained from unconfined compression test (qu/2). The stress reaches to a well defined point and then to the residual state in the direct shear test. Direct shear tests were also performed on the geomaterial to gain the correlation between two parameters such as compressive strength test and shear strength.7 Yoonz et al.

(2004) studied the mechanical characteristics of the light-weighed soil (LWS) made up of EPS, water, dredged clay and cement through a series of triaxial compression tests and unconfined compressive test . The test specimens were prepared in the ratio of EPS, water and cement to dredged clay by percent weight. The stress-strain characteristics, along with the different parameters affecting the strength of the light-weight soil such as initial water content in dredged clay, EPS ratio effect, cement ratio effect, curing pressure effect were studied. The experimental study revealed that the compressive strength of the LWS does not depend upon effective confining pressure. The secant modulus obtained at 50% failure strain is about 20-40 times triaxial compressive strength. The influence of initial water content in the dredged soil is also important as the axial strain in triaxial test decreases significantly with decrease in initial water content in dredged soil. Stark et al. (2004b) has discussed the advantages of lightweight fill materials for embankment by using EPS.

These lightweight fill materials have a density less than soil which reduces the overburden pressure over poor foundation soil such as marine clay thereby reduces the excessive settlements. It was also reported and observed that the magnitude of secondary compression of soft soils can be considerably reduced by using the lightweight materials. Liu et al. (2006) conducted compressive strength tests to study the effect of different mixing ratios of EPS beads, cement and water with respect to soil on the compressive strength, density, modulus of elasticity of the lightweight fill material. From the experimental investigation, it was observed that, the density of lightweight material is highly dependent on percentage of EPS beads added in the mix; however the effect of percentage of cement and water added is insignificant compared less to EPS beads.

The compressive strength of the lightweight material depends on all the three mixing ratio and it increases with increase in the percentage of cement whereas decreases with increase in EPS beads and water. The lightweight material produced has higher density but high compressive strength compared to EPS geofoam block and can be used as an optional material when high strength fill materials are required. Kim et al.

(2008) developed a lightweight soil consisting of dredged clayey soil, cement, and air-foam with waste fishing net as reinforcement for the material. A series of unconfined compression tests and one dimensional compression tests were8 conducted to investigate the strength characteristics of unreinforced and reinforced lightweight soil with fishing net. The lightweight soil specimens were prepared with different composition of cement, water, air-foam and fishing net contents. The results showed that the compressive strength increases with increase in cement content but decreases with increase in water and air-foam content. Inclusion of waste fishing net increases the compressive strength of lightweight soil due to the friction and the bond strength at the interface between waste fishing net and soil mixtures; however increase in the compressive strength was not directly proportional to the percentage of waste fishing net. The air-foam content affected the bulk unit weight of lightweight soil. Zhu Wei et al.

(2008)developed a new geo technical material, sand EPS beads mixture (SEM).Direct shear tests, density test and compression test were performed to study the density and strength properties of the SEM. The results showed and revealed that i) water is necessary for preparation of specimen, but has no different effect on shear strength and dry density of the SEM, ii) dry density of the SEM decreases linearly with volumetric EPS beads content, but increases with preload pressure, and iii) the shear strength of the SEM changes little with volumetric EPS beads content and gravimetric water content but increases with preload pressure.

Wang and Miao (2009) performed laboratory experimental to study the effectiveness of fill material made from different mixtures of river sand, cement and expanded polystyrene beads. The proportion of sand and EPS beads was measured by volume, while the proportions of sand, water and cement were determined by weight. The compaction test was conducted with different water content proportion to obtain the optimum water content. The test specimens of cubical shape were prepared using the density and water content determined already. The unit weight of lightweight fill material produced was 10 kN/m3. These specimens were tested for unconsolidated undrained triaxial test, consolidated undrained test, unconfined compression test. The outcomes showed that the unconfined compressive strength of proposed material increases with the increase in curing time and cement content. In unconsolidated undrained triaxial test, it was observed that the cohesion of lightweight material has strong influence of cement content; whereas angle of internal friction was not affected much when tested for 7 days and 14 day cured specimen.

In consolidated undrained test, with increase in cement content increases the cohesion value whereas the angle9 of internal friction of soil was found to almost the same compared to UU test. The performance of lightweight fill material was also studied by construction of embankment over soft soil by using 2 dimensional finite element analysis package PLAXIS 2D. The results obtained from FEA were then compared with similar soil embankment stabilized with lime. The results indicated and revealed that there is considerable reduction in the settlement of soft soil with better strength of embankment with lightweight material when compared with the lime stabilized soil embankments.

Deng and Xiao (2010) conducted and performed consolidated drained triaxial tests on EPS sand mixtures to observe the stress-strain characteristic under different confining pressures. The EPS-sand mixtures were produced by adding 0.5, 1.5 and 2.5% of EPS beads by weight of sand which was found to be 26 to 63% lighter than the conventional fill materials. The triaxial specimens were loaded under confining pressures of 100, 200, 300 and 400 kPa.

The results of the investigation showed and revealed that the EPS content and confining pressures were found to be major influencing parameters to the stress-strain and volumetric strain behavior of the mixtures. Increase in EPS content increases volumetric strain and decreases the shear strength. Increase in confining pressures enhances the strength of the mixture.

EPS content dependent strain increment equations were also derived by compromising Cam-clay and modified Cam-clay, and used to model the stress-strain characteristics of EPS-sand mixtures. The established equations were verified being able to depict the stress-strain observations of EPS-sand specimens, at least for the ranges of EPS contents and confinements. Onishi et al. (2010) carried out series of triaxial compression tests on cement stabilized sand with EPS beads. The change in strength and deformation properties with increase in EPS beads content is studied and observed. The findings reported that the unit weight of the geomaterial produced can be reduced to a greater extent by addition of EPS beads but on the other hand mixing of such material can degrade the strength and deformation properties of the geomaterial.

However, this degradation can be effectively controlled by addition of appropriate amount of cement. Based on the outcomes from the study, the practical implications of designs of these types of lightweight geomaterials are also discussed in terms of unit weight, strength and deformation characteristics.10 Gao et al. (2011a) discussed the geotechnical properties of lightweight geomaterial called EPS composite soil (EPSCS) made up of clay, cement, water and EPS. The properties such as unit weight, compressive strength and modulus, deformation behavior, permeability, dynamic property using creep behavior, cyclic triaxial test and water absorbability. The advantages of the lightweight geomaterial in the geotechnical applications are discussed with some case histories. Based on this study, some future scope of research is also suggested and projected. Gao et al.

(2011b) carried out a series of cyclic triaxial tests to understand the strength and deformation characteristics of lightweight sand EPS soil (LSES). A united framework was suggested for LSES for setting up deformation and strength characteristics by failure cyclic number that corresponds to complete degradation of LSES structure. Cylindrical shaped test specimens with diameter 61.8 mm and height 140 mm were prepared using different mix ratios.

The cyclic stress-strain relationship along with Modulus Reduction Curves for LSES was studied. The experimental investigation showed that LSES possesses good resilient- elasticity recovery ability due to presence of EPS beads which play an important role in energy consumption, affected by which, the cyclic stress–strain curves of LSES under low confining pressures show remarkably linear type. The behavior of LSES under cyclic loading was found to be clearly different from those of sand or cemented sand or EPS. The LSES specimens exhibit brittle failure. Gao et al.

(2012) performed 2D finite element simulation of the embankment constructed with lightweight geomaterial (EPSCS already mentioned in Gao, 2011a) having unit weight 11 kN/m3 over soft clay to determine and study the settlement, soil pressure and pore water pressure and to improve the safety of the ground. The comparison was made between EPSCS and embankment with conventional fill material having unit weight of 18 kN/m3. Compared with the conventional embankment, EPSCS embankment can effectively reduce the settlement problems, soil pressure and excess pore water pressure and so as to improve and safe guard the safety of the ground. Miao et al. (2013) proposed a new lightweight fill material consisting of EPS beads, cement and the hydraulic sand from the Yangtze River, for its application in settlement problems associated with bridge approach embankments over soft soil. The11 experimental investigation and study was carried out to understand the mechanical properties of lightweight material such as standard Proctor tests, unconfined compression tests, unconsolidated-undrained tests, California Bearing Ratio (CBR) tests, and consolidated-undrained tests. The test results showed that proposed lightweight fill material possess consentient properties which suit as a backfill material in highway embankment projects. A field study was also performed to verify the performance of the embankment backfilled with this lightweight material, which resulted in a smaller settlement than the embankment backfilled with lime-stabilized soil.

Qi et al. (2013) conducted permeability tests on geomaterial prepared with EPS beads, sand and cement. The effect of different mixing ratios, curing age and applied consolidation pressure on permeability of the geomaterial produced was studied through laboratory experimental tests using consolidation parameter. The test results indicated that the permeability of EPS beads-mixed lightweight soil decreases with the increasing of curing age and cement ratio, and decreasing of EPS beads ratio and particle size. The coefficient of permeability of EPS beads-mixed lightweight soil decreases with the increase of consolidation pressure and the decreasing trend is slow down under large consolidation pressure. The extent of reduction of permeability coefficient with the increase of consolidation pressure is comparatively larger under large EPS beads ratio or small cement ratio.

Padade and Mandal (2014) conducted a study of Expanded Polystyrene-Based Geomaterial with Fly Ash. This paper reports the engineering behavior of proposed expanded polystyrene-based geomaterial (EPGM) with ?y ash through a laboratory experimental study. The proposed geomaterial is prepared by blending ?y ash with expanded polystyrene (EPS) beads and a binder such as cement. The effects of different compositions and different mix ratios between EPS beads and ?y ash (0.5–2.5%), cement and ?y ash (10–20%), and water and ?y ash (50 and 60%) on density, compressive strength, and initial tangent modulus of the geomaterial formed were studied for 7 days and 28 days duration. The authors observe that the density of EPGM can be effectively controlled by the quantity of EPS beads added in making the material.

With the inclusion of merely 0.5–2.5% of EPS beads to ?y ash (by weight), the density of the geomaterial formed can be reduced from1,320 to 725 kg/m3. The compressive strength of EPGM increases considerably if cement-to-?y12 ash ratios of 10, 15, and 20% are used. Compared with EPS block geofoam, EPS beads mixed geomaterial has higher density but higher compressive strength and higher stiffness. Thus the geomaterial developed in the current study can be used as a substitute for EPS geofoam block when strong ?ll materials with high strengths are required. Ram Rathan Lal and Badwaik (2015) conducted experimental study on bottom ash and expanded polystyrene beads–based Geomaterial. The increasing production of bottom ash and its disposal in an eco-friendly manner is a matter of concern.

This paper concisely describes the suitability of bottom ash to be used in civil engineering applications as a way to minimize the amount of its disposal in the environment and in the direction of sustainable development. The proposed geomaterial was prepared by blending bottom ash with expanded polystyrene (EPS) beads and a binder such as cement. The experiments were conducted by adding EPS beads with different mix proportions.

The mix ratio percentages 0.3, 0.6, 0.9, 1.2, and 1.

5 were used in this study. The cement to bottom ash (C/BA) ratios of 10 and 20% were used in the study. All the ratios used in the study are with respect to weight of bottom ash. The compressive strength of geomaterial was evaluated for curing periods of 7, 14, and 28 days. The effects of various mix ratios, cement content, and curing periods on the density, compressive strength, and initial tangent modulus was studied and the results were incorporated. Test result indicated that the density of geomaterial reduced from 650 to 360 kg/m3 with addition of EPS beads from 0.3 to 1.5%.

For a particular curing period, compressive strength reduced marginally following the inclusion of EPS beads in geomaterial. For each mix ratio, compressive strength increased with increasing curing periods. The initial tangent modulus of the geomaterial decreased with increasing mix ratio values.

The prepared geomaterial was light in weight comparatively and it can be used as a substitute to conventional fill materials. Marjive and Ram Rathan Lal(2016)carried out an experimental study on stone dust and EPS beads based material, a series of compressive strength were performed on newly developed construction material (NDCM) prepared by using stone dust, expanded polystyrene (EPS) beads and binder material such as cement. Two different densities of EPS beads 22 kg/m3 and 16 kg/m3 were used in this study. The mix ratio percentages used in the study are 0.25, 0.75, and 1.25.

The compressive strength of material was determined for curing periods of 7, 14, and 28 days. For a particular mix13 ratio value, compressive strength of material increased with increasing curing period and for a particular curing period value it decreased with increasing mix ratios. The density of NDCM was found to be decreased with increasing mix ratios for both the densities EPS beads. For a particular mix ratio, NDCM prepared using EPS beads of density 16 kg/m3 shows lower density than that of prepared using density 22 kg/m3. For a particular mix ratio and for each curing days, NDCM prepared using EPS beads of density 22 kg/m3 shows higher compressive strength than EPS beads of density 16 kg/m3.

Ashna et al. (2017) carried out an experimental study on stress-strain behavior of EPS beads-sand mixture. In this study, Expanded Polystyrene beads of two sizes, namely 1 mm and 2 mm were mixed with sand at proportions 0.25%, 0.5% and 0.

75% by weight to obtain a new geo-material. A Tri-axial compression test was done at three different confining pressures. The results showed that by increasing the EPS content by weight, maximum deviator stress and angle of internal friction decreased. However, bead in the mix contributed to the lightweight aspect which can be used in several geotechnical applications. The stress strain behavior of the mix was found to be dependent on size of bead, bead content and confining pressures. The study concluded with, dry unit weight decreases with the addition of EPS beads into sand which shows that it has the potential characteristic of a lightweight fill, Angle of internal friction decreased with increase in bead content, Deviatoric stress decreased with increase in % by weight of beads for both bead sizes, Smaller sized beads showed greater strength compared to larger sized beads was observed. From available permanent literature, lightweight geomaterials are prepared by using EPS beads, soil and cement as binder material (Tsuchida et al., 2001; Yoonz et al.

, 2004; Stark et al., 2004b; Liu et al., 2006; Kim et al, 2008; Wang and Miao, 2009; Deng and Xiao, 2010; Onishi et al., 2010; Gao et al., 2011a; 2011b; 2012; Miao et al., 2013 ; Qi et al.

, 2013), a few study has been done by using EPS beads, fly ash and cement as binder material (Padade and Mandal 2014, Ram Rathan Lal and Badwaik 2015; Marjive and Ram Rathan Lal 2016; Ashna et al 2017). However, it is observed that some of the aspects of mix ratios are not discussed adequately in the study. As studied and reported by Liu et al. (2006), the usage of EPS geofoam blocks in infrastructure projects suffer from some disadvantages viz. (i) EPS geofoam blocks14 are usually of regular shapes, therefore it is not possible to use them to fill in irregular volumes; (ii) shapes EPS geofoam blocks cannot be fabricated on site, hence its transportation is necessary on site and (iii) So as to suit site conditions the basic properties of EPS geofoam blocks cannot be modified.

Several researchers have done experimental and numerical investigations on lightweight fill material prepared by using EPS beads, soil and cement (e.g. Tsuchida et al. 2001, Yoonz et al. 2004; Liu et al. 2006; Kim et al. 2008; Wang and Miao 2009; Deng and Xiao 2010; Onishi et al.

2010; Gao et al. 2011a, 2011b, 2012; Miao et al., 2013 and Qi et al. 2013). A few research by Padade & Mandal 2014; Ram Rathan Lal & Badwaik 2015; Ram Rathan Lal et al. 2016; Ashna et al. 2017 in the light of using fly ash as EPGM material has been done.

Shin et al. (2011) proposed application of light soil particles (LSP) made of expanded polystyrene (EPS) material in mortar. It is well studied from the available literature that numerous studies have been carried out to understand the behavior of lightweight geomaterial (EPGM) prepared by using EPS beads, soil and cement as binder material. However, much attention is not paid to develop geomaterials by using fly ash instead of soil or any other material in combination with EPS beads and cement.

As per the problems mentioned and detailed by Das and Yudbhir (2005) and Gandhi et al. (1999), Padade & Mandal 2014 the present research work was carried out by using fly ash and EPS beads in the light of long term strength gained by the specimens in comparison with specimens prepared without beads. Fly ash is the finely divided residue that results from the combustion of pulverized coal and is transported from the combustion chamber by exhaust gases. Over 61 million metric tons of fly ash was produced in 2001.The total generation of fly ash in 2010-11 was 131.09 million-tonnes. The data of fly ash generation and utilization for year 2015-16 received from 71 Power Utilities in India was 176.

7441 Million- tonne which is 2.6 times more as compared to 2001 report .Therefore with an exponential increase in population of India there has been increasing in power demand and supply. This directly led to increase in production of fly ash. Leading to direct impact on global environment. In India, thermal power plants produce a huge quantity of fly ash. Therefore, an attempt has been made in the direction of using fly ash instead of soil for the preparation of geomaterial along with EPS beads and cement.15 The present study mainly focuses on mechanical behavior of EPS based geomaterial using fly ash and cement as binding material.

Compared with other similar geomaterials like EPS geofoam blocks, and cement-soil-EPS lightweight fills the proposed EPGM has some advantages that includes cement saving, irregular shape filling and indirectly proper utilization of fly ash in geotechnical engineering application which reduces the environmental pollution related problems to disposal of fly ash and finally better to overcome the thermal insulation problems. In comparison with the EPS geofoam block, the lightweight fill that includes EPS beads may be controlled in terms of both density, shear strength, compressive strength . 2.4 Main Aims and Objectives of the Proposed Work The primary aim of this study was to investigate the feasibility of using a significant proportion of fly-ash for beneficial purpose in civil engineering applications that is sustainable and environmentally friendly. To study strength characteristics of fly ash and EPS beads in combination with cement and water. This study reports the results of an experimental investigation into the engineering properties, such as compressive strength depending on the proportion of beads to fly ash, cement to fly ash, water to fly ash ratio. The objective is also to promote safe uses of fly ash material along with EPS beads in civil engineering projects.

The detailed laboratory investigations were planned and carried out for the determination of the best product and the best mix design. Thus, the main objective of the study undertaken in this dissertation work may be summarized as under: i The primary objective of the present study deals with determination of physical properties of locally available fly ash and its suitability as a construction material. ii To evaluate compressive strength of specimen prepared from different composition of EPS beads, cement and water along with fly ash and study its long term strength and stiffness. iii Preparation of lightweight material using the proportions mentioned by Padade & Mandal (2014) iv Density measurement for light weight material. v Effect of mix ratios on density, compressive strength and stiffness.16 vi Stress-Strain behavior of the material.

The optimal mixture of locally available fly ash stabilized with cement and EPS beads was selected among experiments under consideration to produce the alternative EPGM material mix. 2.5 Scope of Present Work Considering above stated aims and objectives, the scope of present work is defined as follows, A new expanded polystyrene (EPS) based geomaterial has been proposed with different mix ratios between the four components (EPS beads, fly ash, cement and water). The mix ratios were based on fly ash as basic material with respect to which mass of EPS beads, cement and water were taken. The geomaterial has been prepared with thirty six different combinations and test results of 144 samples of EPS beads based geomaterial are discussed with respect to the long term effect of these mix ratios on density, stress-strain nature, variation in compressive strength, effect of curing period on strength development and initial tangent modulus is determined and presented in the study.

a. The lightweight geomaterial (LWGM) evolved from the study by using fly ash and expanded polystyrene beads has high potential for its use in several geotechnical constructions in infrastructure development works in India. b.

The composite material of required lightness and strength can be formed by adjusting EPS beads (B) content from 0.5% to 2.5% of weight of fly ash (FA). However, for appropriate strength development 10%, 15%and 20% cement (by weight) is needed.

d. As compared to traditional coarse grained moorum type earth commonly used in embankment construction and backfilling, the suggested LWGM is 50% light and 16.5 times strong. e. The LWGM developed from the study can be used in the form of blocks of any size pre-casted and cured at casting yard near site or as wet mix to be placed in bulk for the desired construction job.17 f. Embankments with very steep slopes can be formed by using LWGM. This results in substantial saving of land area occupied by embankment.

Besides, the volume of embankment material is significantly reduced.CHAPTER 3 MATERIALS 3.1 Fly Ash Flyash, is known as one of the residues generated by coal combustion, and is composed of the fine particles that are driven out of the boiler with the flue gases. The fly ash is continuously produced in unimaginably huge quantity in our country from several thermal power plants.

In absence of its timely and effective disposal it creates many environmental hazards. This fly ash forms the main constituent of the proposed geomaterial. Fly ash is an industrial waste product from coal based power station. The fly ash is slightly alkaline in reaction. Fly ash is a good material for a wide range of applications viz. by geopolymerisation, by preprocessing, by heat treatment process can be utilized for manufacturing of cement, substitute of cement in concrete, manufacture of bricks, blocks, ceramic tiles, paving blocks, self glazed tiles, immobilization, mechanical activation, refractory bricks, synthetic granite etc. Classification of Fly ashes classified by precise particle size requirements, thus assuring a uniform, quality product. In the present study fly ash is collected in wet state from Koradi thermal power plant, Koradi, Nagpur, India having specific gravity 2.

18 Class F fly ash is available in the largest quantities. Class F is generally low in lime, usually under 15 percent, and contains a greater combination of silica, alumina and iron (greater than 70 percent) than Class C fly ash. Class C fly ash normally comes from coals which may produce an ash with higher lime content generally more than 15 percent often as high as 30percent. Elevated CaO may give Class C unique self-hardening characteristics. Fly ash used for the present laboratory study is taken from Koradi power plant, Nagpur which is stored in gunny plastic bags and it is classified as class F. Flyash having following components are summarized below, The percentage of basic chemical compounds present in fly ash were SiO2 (61.

15%), calcium oxide, CaO (3.31%),Magnesium oxide, MgO(0.64%),total Sulphur as Sulphur trioxide ,SO3(0.127%),Silicon dioxide (SiO2) +aluminium oxide(Al2O3)+ iron oxide(Fe2O3) (94.95%),Total loss on ignition was (0.

34%). Depending on percentage of chemical compounds present in fly ash, as per ASTM C618-08, it is classified as Class F. The specific gravity of fly ash is 2.

18. Fineness by sieving is19 9.30%, compressive strength 28 days is 34.50N/mm2, consistency as 27.5%, soundness by Autoclave method as 0.039% respectively.

3.2 Expanded polystyrene beads Expanded Polystyrene (EPS) is a super lightweight synthetic cellular material that was invented in 1950. This rigid plastic foam type material is being used in geotechnical constructions since 1960’s when a product category ‘Geofoam ‘was discovered. EPS is generally used as packaging material for sensitive appliances and electronic items during transportation. EPS is a polymeric form of its monomer, Styrene. It is white in colour, and is manufactured from a mixture of 5-10% gaseous blowing agent, most commonly pentane or carbon dioxide and 90-95% polystyrene by weight. The solid plastic is expanded into foam by the use of heat; usually steam. EPS can be used in the form of blocks (also called EPS geo-foam) and beads.

Expanded polystyrene beads used are spherical and round in shape with diameters ranging between 2 to 3 mm. These highly compressible EPS beads have a density 20 kg/m3. Compared to EPS shreds and strips, EPS beads make the composite material with the lowest unit weight. An expanded polystyrene bead was used as a mixing component.

These closed cell particulates are often called as polystyrene pre-puffs in the manufacturing sector. The lightness of the material is accomplished by adding EPS beads in fly ash. Expanded polystyrene beads were spherical and round in shape with diameters ranging between 2 to 4 mm and having durable property. It was aimed to develop a composite material containing larger percentage of EPS beads and lesser quantity of cement. The trial mixing and testing revealed that the beads content should be 0.5% to 2.5% of the weight of fly ash.

EPS beads having the chemical formula (C8H8) n, density in the range of 0.96 -1.04 gm/cm3, having melting point approximately 240oC (464oF) and decomposes at lower temperature, thermal conductivity 0.033 W/ (m-k), Refractive index (nD) 1.

6; dielectric constant 2.6(1KHz-1GHz), was obtained from a regional supplier of EPS material for engineering, packaging, manufacturing industries Thermo Pack Industries, Kalamna market road, Nagpur, India. 3.3 Cement An Ordinary Portland cement of 43 grade (IS 8112: 1989) was used as a binding material. Cement is a binder, a substance used for construction that sets, hardens and adheres to other materials, binding them together. Cement is seldom used20 on its own, but rather to bind sand and gravel together.

The density of ordinary Portland cement was 3.15 g/cm³(3150 kg/m3). This type of cement should confirm according to IS: 8112-1989. 3.

4 Water Potable water is used to mix these materials. Potable is water safe enough to be consumed by humans or used with low risk of immediate or long term harm. In most India, the water supplied to households, commerce and industry meets drinking water standards, even though only a very small proportion is actually consumed or used in food preparation.

Typical uses (for other than potable purposes) include toilet flushing, washing, and landscape irrigation. Figure 3.1 Photographic view of EPS beadsCHAPTER 4 EXPERIMENTAL PROGRAM The experimental program was planned with an objective to understand and investigate the suitability of fly ash. The following chapter discusses the laboratory equipment, method and techniques utilized throughout the testing program. 4.1 Mix proportion The work plan comprise of mix proportions and preparation of specimens with several different combination of Fly ash, Cement at suitable W.

C. (%). In the experimental study three different mix ratios were used to prepare the EPGM. The mix proportion is defined as the proportion of two materials by weight. These ratios are as follows –EPS beads to fly ash (B/FA), cement to fly ash ratio (C/FA), and water to fly ash (W/FA). A pilot project work was also conducted before deciding the range of limits of different mix ratios and specimen of size 100 X 100 X 100 mm was taken into consideration. During the sample preparation it was observed that beyond 2.

5% proportion of (B/FA) ratio the sample segregates, due to volumetric increase of beads as compared to fly ash .The cement to fly ash ratio (C/FA) was also fixed between 10% to 20% because C/FA ratio below 10% was insignificant as the components were found to be segregated after curing of one day. And the last component of water to fly ash ratio (W/FA) ratio cannot be formed into homogeneous slurry below water to fly ash of 40%. Table gives the study for preparation of the EPGM. Table 4.

1 Mix ratios used to prepare EPGM Mix ratios EPS beads to fly ash (B/FA)% Cement to fly ash (C/FA)% Water to fly ash (W/FA)% 0.5, 1.0, 1.5, 2.0, 2.5 10 40 0.5, 1.0, 1.

5, 2.0, 2.5 15 40 0.5, 1.0, 1.5, 2.0, 2.5 20 40 0.

5, 1.0, 1.5, 2.0, 2.5 10 50 0.5, 1.

0, 1.5, 2.0, 2.5 15 50 0.5, 1.

0, 1.5, 2.0, 2.5 20 50 NOTE: B/FA = EPS beads to fly ash ratio and C/FA= Cement to fly ash ratio22 4.2 Experimental Program Experimental program consists of determination of ? Preparation of lightweight material using the proportions mentioned by Padade ; Mandal (2014) ? Density measurement for light weight material. ? Compressive strength test for long term of 7/14/28/56 days on cubical specimen. ? Effect of mix ratio on density, compressive strength and stiffness. ? Stress-strain behavior of the material.

4.3 Preparation of test specimen The EPS beads mixed geomaterial was prepared as follows. The dried fly ash was weighed and placed into a container. The cement was also added according to C/FA ratio and dry mixing was carried out first. For compound mix, potable water was added slowly according to W/FA ratio specified and the fly ash–cement-water mixture was mixed into homogeneous slurry as shown in Figure 4.

1(a). The EPS beads were then slowly added into slurry and mixing continued until the beads were evenly distributed well within the slurry. With some more time of mixing, fresh EPS beads mixed geomaterial was produced in a slurry form as shown in Figure 4.1(b). After a thorough mixing the slurry formed was cast into specimens for compressive strength tests. These compressive strength test specimens were prepared in a cube shape moulds having dimension 100 mm × 100 mm × 100 mm as shown in Figure 4.2.

After setting time, all specimens were removed from the moulds and placed in the water tank for curing until the date of testing as shown in Figure 4.3. The EPGM specimens after curing are shown in Figure 4.4.

The curing periods used in experimental program were 7 days, 14 days, 28 days and 56 days. 30 tests were conducted on EPGM samples for each curing period. Therefore, the results of 120 tests are reported in the study along with test results of 24 tests obtained from mixing of fly ash along with cement and water without beads for a comparative study.23 (a) (b) Fig.

4.1 Preparation of EPGM (a) dry cement and fly ash mix and (b) slurry after mixing of EPS beads and water Fig. 4.2 EPGM specimen casting in moulds Fig. 4.3 EPGM specimens in curing tank24 Fig.

4.4 EPGM specimens after curing 4.4 Test procedure After curing, the specimens were air dried and dimensions of each specimen were measured using a vernier calliper for volume determination (Figure 4.5 a ). The mass of each specimen was measured using an electronic balance having accuracy of 0.01 g.

These measurements were used to calculate the density of specimen by dividing mass with volume. Compression test was performed on EPGM specimens to measure compressive strength and stiffness. Compression tests were conducted in load frame machine at a deformation rate of 1.2 mm/min as shown in Figure 4.5(b) having a capacity of 5 tonnes. The maximum load at failure of specimen with corresponding deformation was noted as a compressive strength.25 (a) (b) (Fig.

4.5 a) Specimen measured with vernier calliper 4.5 b) Compressive strength tests on EPGM test specimen on load frame machine. Apparatus: Load frame Machine, cube specimen. Procedure: • After preparing a mix, the cubical test specimens of dimensions 100x100x100 mm is prepared for compressive strength. • The Compressive Strength test was performed as shown in the figure.

• The specimen is placed between steel plates under loading frame. • Load is applied axially at uniform rate till failure. • Maximum load at failure divided by average area of bed face gives compressive strength.

26 Calculation Compressive Strength (kN/m2) =;#3627408396;;#55349;;#56346;;#55349;;#56369;.;#3627408421;;#3627408424;;#55349;;#56346;;#3627408413; ;#55349;;#56346;;#3627408429; ;#3627408415;;#55349;;#56346;;#3627408418;;#3627408421;;#3627408430;;#3627408427;;#3627408414; ;#3627408418;;#3627408423; ;#3627408420;;#3627408397;;#55349;;#56320;;#3627408431;;#3627408414;;#3627408427;;#55349;;#56346;;#3627408416;;#3627408414; ;#55349;;#56320;;#3627408427;;#3627408414;;#55349;;#56346; ;#3627408418;;#3627408423; ;#3627408422;;#3627409360; (a) (b) Fig. 4.6a) Cube Compressive strength test set up b) Cube specimen after failure 4.

4.2 Determination of Density One of the important parameter for EPGM is its density. The specimens were weighed by using electronic weighing balance.

The density of the material block was calculated by dividing weight with volume of the specimen. Apparatus ? Electronic weighing balance. Calculation Density =;#3627408406;;#3627408414;;#3627408418;;#3627408416;;#3627408417;;#3627408429; ;#3627408424;;#3627408415; ;#3627408428;;#3627408425;;#3627408414;;#3627408412;;#3627408418;;#3627408422;;#3627408414;;#3627408423;;#3627408429; ;#3627408418;;#3627408423; ;#3627408420;;#3627408397;;#3627408405;;#3627408424;;#3627408421;;#3627408430;;#3627408422;;#3627408414; ;#3627408424;;#3627408415; ;#3627408428;;#3627408425;;#3627408414;;#3627408412;;#3627408418;;#3627408422;;#3627408414;;#3627408423; ;#3627408418;;#3627408423; ;#3627408422;;#3627409361;27 4.4.

3 Stiffness modulus 4.4.3.1 Initial Tangent Modulus The initial tangent modulus, Ei , is often used to characterize the stiffness of the geomaterial. It is determined as the slope of the tangent line to the origin of the stress–strain curve. Using the compressive testing results, the initial tangent modulus of the alternative geomaterial were calculated and plotted against the corresponding compressive strengths.

CHAPTER 5 RESULTS AND DISCUSSIONS 5.1 General The properties of lightweight geomaterial such as density, compressive strength and initial tangent modulus are studied and discussed in this chapter in detail corresponding to different mix ratios used for its preparation. 5.2 Effect of mix ratios on density of lightweight geomaterial Figures 5.1 and 5.2 represent the variation of density with respect to B/FA ratio.

It can be clearly noted that the density of lightweight geomaterial decreases with increase in B/FA ratio. Lightweight geomaterial with B/FA ratios 0 to 2.5% have density in the range of 1665 to 772 kg/m3. This is due to the weight of EPS beads which is very less compared to fly ash.

Replacement of nearly 0.5% beads increases its volume significantly which results in dreased density of geomaterial. Increase in B/FA ratio from 0.

5 to 2.5% reduces the desnity of geolmaterial in the range of 19 to 51%. However, increse in C/FA ratio does not show any effect on density of lightweight geomaterial.

Increase in C/FA ratio from 10 to 20% resulted in density variation within 0.5 to 1%. The change in density of lightweight geomaterial is noticable for B/FA ratio however, it is insignificant for C/FA ratio. The density of lightweight geomaterial decreases with increase in W/FA ratio but the change is marginal. Increase in W/FA ratio from 40 to 50% decreases the density of lightweight gematerial within the range of 1 to 3%. From above discussions, it is very clear that B/FA ratio is a governing factor density of geomaterial whereas the other factors (C/FA) and (W/FA) do not have any effect on density.29 (a) (b) 05001000150020000.

00.51.01.52.02.53.0Density, ?(kg/m3)B/FA(%)C/FA=10%C/FA=15%C/FA=20%7 DaysW/FA = 40% 05001000150020000.00.

51.01.52.02.53.0Density, ?(kg/m3)B/FA (%)C/FA=10%C/FA=15%C/FA=20%14 DaysW/FA = 40%30 (c) (d) Figure 5.

1 Effect of B/FA ratio on density of geomaterial at C/FA ratio 40% for W/FA ratios (a) 7 days, (b) 14 days, (c) 28 days and (d) 56 days 05001000150020000.00.51.01.52.

02.53.0Density, ?(kg/m3)B/FA (%)C/FA=10%C/FA=15%C/FA=20%28 DaysW/FA = 40% 05001000150020000.00.51.01.

52.02.53.0Density, ?(kg/m3)B/FA (%)C/FA=10%C/FA=15%C/FA=20%56 DaysW/FA = 40%31 (a) (b) 05001000150020000.00.51.01.52.02.53.0Density, ?(kg/m3)B/FA (%)C/FA=10%C/FA=15%C/FA=20%7 DaysW/FA = 50% 05001000150020000.00.51.01.52.02.53.0Density, ?(kg/m3)B/FA(%)C/FA=10%C/FA=15%C/FA=20%14 DaysW/FA = 50%32 (c) (d) Figure 5.2 Effect of B/FA ratio on density of geomaterial at C/FA ratio 50% for W/FA ratios (a) 7 days, (b) 14 days, (c) 28 days and (d) 56 days 05001000150020000.00.51.01.52.02.53.0Density, ?(kg/m3)B/FA(%)C/FA=10%C/FA=15%C/FA=20%28 DaysW/FA = 50% 05001000150020000.00.51.01.52.02.53.0Density, ?(kg/m3)B/FA(%)C/FA=10%C/FA=15%C/FA=20%56 DaysW/FA = 50%33 Considering the above graphical representation given in Figures 5.1 and 5.2 which shows nearly equal values for the density with respect to C/FA ratio as discussed earlier, the average density was calculated considering the curing period and plotted against C/FA ratio as shown in Figures 5.3 (a) and (b). For the specimen cured for 7, 14, 28 and 56 days, the change in density of geomaterial is found to be insignificant. (a) (b) Figure 5.3 Effect of mix ratio on density of geomaterial with C/FA ratio for (a) 40% and (b) 50% 0500100015002000510152025Average Density, ?a(kg/m3)C/FA (%)B/FA = 0%B/FA = 0.5%B/FA = 1.0%B/FA = 1.5%B/FA = 2.0%B/FA = 2.5%W/FA= 40% 0500100015002000510152025Average Density, ?a(kg/m3)C/FA (%)B/FA = 0%B/FA = 0.5%B/FA = 1.0%B/FA = 1.5%B/FA = 2.0%B/FA = 2.5%W/FA= 50%34 5.3 Effect of mix ratios on compressive strength Figures 5.4 and 5.5 represent the effect of B/FA ratio on compressive strength of geomaterial. It is important to note that the representation of relationship between compressive strength and mix ratios are given on same scale for all the cases. This is done to identify the nature of the geomaterial with respect to beads (B/FA), cement (C/FA), water (W/FA) and curing period. The compressive strength decreases with increase in B/FA ratio from 0.5 to 2.5%. Within this range the change in compressive strength was found to be 25 to 68%. The decrease in compressive strength was observed due to increase in the proportion of highly compressible beads in the mix. It is important to note that 0.5% increase in beads by weight substantially increases its volume resulted in reduced compressive strength. However, the strength increases with increase in C/FA ratio from 10 to 20% for a particular B/FA ratio having same W/FA ratio. Increase in W/FA ratio affects the compressive strength of geomaterial which decreases with increase in W/FA ratio from 40 to 50%. Within this range of increase, the decrease in compressive strength is found to be in the range of 7 to 16%. Therefore, it can be referred that the mixing ratios required high precision with respect to W/FA ratio. It is interesting to observe that specimen without EPS beads have compressive strength less than specimen with 0.5% beads and equal or some times less than 1.0 to 1.5% beads for most of the cases. This has been clearly observed in stress-strain curves and discussed in detail therein. The nature of relationship between compressive strength and B/FA is found to be non-linear for all the cases.35 (a) (b) (c) (d) Figure 5.4 Effect of mix ratio on compressive strength of geomaterial with C/FA ratio at W/FA ratio 40% for (a) 7 days, (b) 14 days, (c) 28 days and (d) 56 days 020004000600080001000000.511.522.53Compressive Strength, ?(kPa)B/FA (%)C/FA = 10%C/FA = 15%C/FA = 20%7 DaysW/FA=40% 020004000600080001000000.511.522.53Compressive Strength, ? (kPa)B/FA (%)C/FA = 10%C/FA = 15%C/FA = 20%14 DaysW/FA=40% 020004000600080001000000.511.522.53Compressive Strength, ? (kPa)B/FA (%)C/FA = 10%C/FA = 15%C/FA = 20%28 DaysW/FA=40% 020004000600080001000000.511.522.53Compressive Strength, ? (kPa)B/FA (%)C/FA = 10%C/FA = 15%C/FA = 15%56 DaysW/FA=40%36 (a) (b) (b) (d) Figure 5.5Effect of mix ratio on compressive strength of geomaterial with C/FA ratio at W/FA ratio 50% for (a) 7 days, (b) 14 days, (c) 28 days and (d) 56 days 01000200030004000500000.511.522.53Compressive Strength, ? (kPa)B/FA (%)C/FA = 10%C/FA = 15%C/FA = 20%7 DaysW/FA = 50% 01000200030004000500000.511.522.53Compressive Strength, ? (kPa)B/FA (%)C/FA = 10%C/FA = 15%C/FA = 20%14 DaysW/FA = 50% 01000200030004000500000.511.522.53Compressive Strength, ? (kPa)B/FA (%)C/FA = 10%C/FA = 15%C/FA = 20%28 DaysW/FA = 50% 01000200030004000500000.511.522.53Compressive Strength, ? (kPa)B/FA (%)C/FA = 10%C/FA = 15%C/FA = 20%56 DaysW/FA = 50%37 5.4 Effect of curing on compressive strength of geomaterial Figures 5.6 and 5.7 represent the relationship between compressive strength with age of curing of specimens for W/FA ratios of 40% and 50% respectively. It is observed that the effect of curing decreases with increase in B/FA ratio. This may happen due to increase in volume of beads in mix proportion where the water absorption capacity of EPS material is almost negligible. Increase in beads content The relationship shows increase in value of compressive strength almost linearly upto 28 days curing period however, it decreases from 28 to 56 days. Effect of curing beyong 28 days is found to have very less increase in compressive strength. The effect of increase in compressive strength is significant with increase in C/FA ratio and W/FA ratio. With increase in C/FA ratio from 10 to 20% almost double increase in value of compressive strength is observed for same configuration. Similarly, increase in value of W/FA ratio decreases the compressive strength. With nearly 10% increase in value of C/FA ratio decreases the compressive strength by 15 – 26% for the same configuration of B/FA ratio. Therefore, it can be stated that all the three mix ratios affect significantly in terms of curing period on strength.38 (a) (b) (b) (d) (e) Figure 5.6 Effect curing period on compressive strength of geomaterial with C/FA ratio at W/FA ratio 40% for B/FA ratios (a) 0.5%, (b) 1.0%, (c) 1.5%, (d) 2.0 % and (e) 2.5% 02000400060008000100000714212835424956Compressive Strength, ? (kPa)Curing Period (Days)B/FA = 0.5%C/FA=10%C/FA=15%C/FA=20% 02000400060008000100000714212835424956Compressive Strength, ? (kPa)Curing Period (Days)B/FA = 1.0%C/FA=10%C/FA=15%C/FA=20% 02000400060008000100000714212835424956Compressive Strength, ? (kPa)Curing Period (Days)B/FA = 1.5%C/FA=10%C/FA=15%C/FA=20% 02000400060008000100000714212835424956Compressive Strength, ? (kPa)Curing Period (Days)B/FA = 2.0%C/FA=10%C/FA=15%C/FA=20% 02000400060008000100000714212835424956Compressive Strength, ? (kPa)Curing Period (Days)B/FA = 2.5%C/FA=10%C/FA=15%C/FA=20%39 (a) (b) (b) (d) (e) Figure 5.7 Effect curing period on compressive strength of geomaterial with C/FA ratio at W/FA ratio 50% for B/FA ratios (a) 0.5%, (b) 1.0%, (c) 1.5%, (d) 2.0 % and (e) 2.5% 0100020003000400050000714212835424956Compressive Strength, ? (kPa)Curing Period (Days)B/FA = 0.5%C/FA=10%C/FA=15%C/FA=20% 0100020003000400050000714212835424956Compressive Strength, ? (kPa)Curing Period (Days)B/FA = 1.0%C/FA=10%C/FA=15%C/FA=20% 0100020003000400050000714212835424956Compressive Strength, ? (kPa)Curing Period (Days)B/FA = 1.5%C/FA=10%C/FA=15%C/FA=20% 0100020003000400050000714212835424956Compressive Strength, ? (kPa)Curing Period (Days)B/FA = 2.0%C/FA=10%C/FA=15%C/FA=20% 0100020003000400050000714212835424956Compressive Strength, ? (kPa)Curing Period (Days)B/FA = 2.5%C/FA=10%C/FA=15%C/FA=20%40 5.5 Failure pattern The failure patterns of the lightweight geomaterial are also studied under compressive loading condition. It was observed that the failure patterns of test specimens were highly influenced by all the three mix ratios used for preparation of lightweight geomaterial. As B/FA ratio increases the failure pattern of test specimen changes from brittle to ductile behavior. This can also be confirmed by stress-strain curves plotted for different test specimen. However, increase in C/FA ratio changes the failure pattern from ductile to brittle behavior. Most of the test specimen were failed along the diagonal of the cube. The ductile and brittle behavior of failure patterns are depicted in Figures 5.8 and 5.9 respectively. Figure 5.8(a) Test specimen of geomaterial failed under compressive load (Ductile behavior) Figure 5.8(b) Test specimen of geomaterial failed under compressive load (Brittle behavior)41 5.6 Stress-strain behavior The data obtained from compressive strength test was also used to plot the stress-strain curve and to determine stiffness characteristics of lightweight geomaterial. With increase in C/FA ratio the test specimen becomes more brittle. The specimens of geomaterial failed within a strain range of 1 to 2%. The compressive strength and stress-strain behavior of geomaterial are affected by B/FA ratio. The compressive stress is decreased with increase in B/FA ratio for 7, 14, 28 and 56 days cured specimens. It can also be seen that the compressive strength and stress-strain behavior is significantly affected by W/FA ratio. With increasing W/FA ratio, the compressive strength as well as stiffness of EPGM decreased and the stress-strain curves become more ductile. Therefore, it can be stated that, all three mix ratios have significant effect on compressive strength and stiffness characteristics of geomaterial. The stress-strain curves for different mix proportions for different curing periods are shown in Figures 5.9 and 5.10.42 (a) (b) (c) (d) (e) (f) (g) (h) 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ?(%)C/FA=10%C/FA=15%C/FA=20%7 DaysW/FA=40%B/FA=0.5% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%14 DaysW/FA=40%B/FA=0.5% 020004000600080001000000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%28 DaysW/FA=40%B/FA=0.5% 020004000600080001000000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%56 DaysW/FA=40%B/FA=0.5% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA=10%C/FA=15%C/FA=20%7 DaysW/FA=40%B/FA=1.0% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%14 DaysW/FA=40%B/FA=1.0% 020004000600080001000000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%28 DaysW/FA=40%B/FA=1.0% 020004000600080001000000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%56 DaysW/FA=40%B/FA=1.0%43 (i) (j) (k) (l) (m) (n) (o) (p) 01000200030004000500000.511.522.53Compressive Stress, ?c (kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%7 DaysW/FA=40%B/FA=1.5% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%14 DaysW/FA=40%B/FA=1.5% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%28 DaysW/FA=40%B/FA=1.5% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%56 DaysW/FA=40%B/FA=1.5% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA=10%C/FA=15%C/FA=20%7 DaysW/FA=40%B/FA=2.0% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%14 DaysW/FA=40%B/FA=2.0% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%28 DaysW/FA=40%B/FA=2.0% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%56 DaysW/FA=40%B/FA=2.0%44 (q) (r) (s) (t) Figure 5.9 Stress-strain curves for different C/FA ratios for W/FA ratio 40% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA=10%C/FA=15%C/FA=20%7 DaysW/FA=40%B/FA=2.5% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%14 DaysW/FA=40%B/FA=2.5% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%28 DaysW/FA=40%B/FA=2.5% 020004000600080001000000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%56 DaysW/FA=40%B/FA=2.5%45 (a) (b) (c) (d) (e) (f) (g) (h) 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ?(%)C/FA = 10%C/FA = 15%C/FA = 20%7 DaysW/FA = 50%B/FA = 0.5% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%14 DaysW/FA = 50%B/FA = 0.5% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%28DaysW/FA = 50%B/FA = 0.5% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%56 DaysW/FA = 50%B/FA = 0.5% 0500100015002000250000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%7 DaysW/FA = 50%B/FA = 1.0% 050010001500200025003000350000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%14 DaysW/FA = 50%B/FA = 1.0% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%28 DaysW/FA = 50%B/FA = 1.0% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%56 DaysW/FA = 50%B/FA = 1.0%46 (i) (j) (k) (l) (m) (n) (o) (p) 0500100015002000250000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%7 DaysW/FA = 50%B/FA = 1.5% 0500100015002000250000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%14 DaysW/FA = 50%B/FA = 1.5% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%28 DaysW/FA = 50%B/FA = 1.5% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%56 DaysW/FA = 50%B/FA = 1.5% 0500100015002000250000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%7 DaysW/FA = 50%B/FA = 2.0% 0500100015002000250000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%14 DaysW/FA = 50%B/FA = 2.0% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%28 DaysW/FA = 50%B/FA = 2.0% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%56 DaysW/FA = 50%B/FA = 2.0%47 (q) (r) (s) (t) Figure 5.10 Stress-strain curves for different C/FA ratios for W/FA ratio 50% 0500100015002000250000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%7 DaysW/FA = 50%B/FA = 2.5% 0500100015002000250000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%14 DaysW/FA = 50%B/FA = 2.5% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%28 DaysW/FA = 50%B/FA = 2.5% 01000200030004000500000.511.522.53Compressive Stress, ?c(kPa)Axial Strain, ? (%)C/FA = 10%C/FA = 15%C/FA = 20%56 DaysW/FA = 50%B/FA = 2.5%48 As discussed earlier, the specimen with B/FA as 0.5% have compressive strength values more than specimen without beads. This is due to the presence of highly compressible beads in suitable mix proportion where specimen carried higher load with stain 1.5% compared to specimen without beads which failed with less load having strain 1.0%. With little more strain value geomaterial having beads can solve specific purposes whenever required with higher compressive strength. Figures 5.11 (a) and (b) represents the nature of stress-strain curves observed for such condition. (a) (b) Figure 5.11 Stress-strain curves for different B/FA ratios for W/FA ratio (a) 40% and (b) 50% 0100020003000400000.511.522.53Compressive Strength (kPa)Axial Strain, ?(%)C/FA = 20%, W/FA = 40% ; 7 DaysB/FA = 0%B/FA = 0.5%B/FA = 1.0%B/FA = 1.5%B/FA = 2.0%B/FA = 2.5% 0100020003000400000.511.522.53Compressive strength (kPa)Axial Strain, ?(%)C/FA = 20% ; W/FA = 50% 7 DaysB/FA = 0%B/FA = 0.5%B/FA = 1.0%B/FA = 1.5%B/FA = 2.0%B/FA =2.5%49 5.7 Initial tangent modulus Initial tangent modulus is an important property of lightweight geomaterial which gives an idea about the stiffness of material. The stiffness of geomaterial is determined by calculating initial tangent modulus as the slope of stress-strain curve from origin. This stiffness of geomaterial is highly influenced by C/FA ratio. Higher the compressive strength of test specimen higher is stiffness values. For the specimen tested for different curing period, the values of initial tangent modulus are found to be in the range of 112 -2800 MPa. The relationship between compressive strength and initial tangent modulus is well established by fitting a curve as shown in Figure 5.12. These values of initial tangent modulus are higher as compared with earlier developed geomaterial using EPS beads with nearly same density range. Figure 5.12 Relationship between compressive strength and initial tangent modulus of geomaterial The initial tangent modulus values of lightweight geomaterial are much higher as compared to values reported in earlier studies of lightweight geomaterial. The comparison between properties of lightweight geomaterial developed earlier (Liu, et al; 2006, Padade and Mandal 2014) and geomaterial developed in the present study is given in Table 5.1. y = 0.405x + 397.8R² = 0.7780100020003000400050000200040006000800010000Initial Tangent Modulus (kPa)Compressive Strength (kPa)50 Table 5.1 Comparison of geomaterial properties with earlier developed products Property Lightweight fill material Expanded polystyrene-based geomaterial with fly ash Lightweight geomaterial developed in present study (Liu et al., 2006) (Padade andMandal,2014) Density (kg/m3) 700 – 1100 725 – 1320 772 – 1361 Compressive strength (kPa) 100 – 510 158 – 3290 171- 8555 Initial tangent modulus (MPa) 79 – 555 51-500 112 -2800CHAPTER 6 CONCLUSIONS 6.1 General The engineering properties of proposed expanded polystyrene based geomaterial are investigated through a laboratory experimental study. The lightweight geomaterial prepared with EPS beads, fly ash and cement using different mix ratios between beads to fly ash, cement to fly ash and water to fly ash. The effect of these mix ratios on density, compressive strength and initial tangent modulus of this geomaterial is presented. The following conclusions are drawn from the study and summarized hereunder: 6.2 Conclusions The lightweight geomaterial developed in the present study reveals various properties and its application in various geotechnical engineering applications. The density of lightweight geomaterial decreases with increase in B/FA ratio and W/FA ratio. However, the effect of C/FA rati o is insignificant. Compressive strength of geomaterial decreases with increase in B/FA ratio and W/FA ratio and it increases with increase in C/FA ratio. Effect of curing beyong 28 days is found to have very less increase in compressive strength. Strength and stifness characteristics are well co-related in the study which gives an idea about the material and its application for specific purpose. 6.3 Limitations of the study Some of the limitations of the present study are given hereunder: 1. Control of weight of beads is very important in the present study which may not be possible at every place. However, accurate weight is maintained while preparation of test specimen in this study. 2. Threshold value of the geomaterial developed in the present study cannot be specified. 6.4 Future Scope of work The study can be repeated for cylindrical samples with varying aspect ratios.52