Soya Bean Oil based Lubricant for Diesel Engines


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Soya Bean Oil based Lubricant for Diesel Engines

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  3. 3. CONTENTSCHAPTER No. TITLE PAGE No. List of Tables v List of Figures vi List of Abbreviations vii Abstract viii1. Introduction 1 1.1 Need for alternate lubricants 1 1.2 Lubricating oil 22. Properties of Lubricating Oil 3 2.1 Flash Point 3 2.2 Fire Point 3 2.3 Cloud Point 3 2.4 Pour Point 3 2.5 Specific Gravity 3 2.6 Sulphur Content 3 2.7 Adhesiveness 4 2.8 Kinematic Viscosity 4 2.9 Viscosity Index (VI) 4 2.10 Volatility 53. Scope of This Project 6 iii
  4. 4. 4. Vegetable Oils and Esterification 7 4.1 Introduction 7 4.2 Production of soys bean methyl ester 7 4.2.1 Transesterification process 8 4.2.2 Materials required 9 4.2.3 Method adopted 9 4.2.4 Soap formation 10 4.2.5 Separation & draining of glycerol 11 4.3 Washing procedure 12 4.3.1 Significance of washing 12 4.3.2 Removal of Unreacted methanol 12 4.3.3 Washing techniques 13 4.3.4 Washing technique adopted 15 4.3.5 Drying of washed methyl ester 165. Determination of Viscosity 176. Determination of Viscosity Index 197. Results of the Lubricant Properties 208. Conclusion 219. References 22 iv
  5. 5. LIST OF TABLESTABLE No. TITLE PAGE No.2.1 Desired Properties of Lubricants 55.1 Kinematic Viscosity of some oil samples 186.1 Calculation of Viscosity Index 197 .1 Results of the lubricant properties 20 LIST OF FIGURESFIG No. TITLE PAGE No. 4.1 Transesterification reaction 8 4.2 Preparation of sodium methoxide solution 10 & adding it to oil 4.3 Separation & Draining of Glycerol 11 4.4 Removal of Unreacted methanol 13 4.5 Washing Techniques 14 4.6 Washing Technique Adopted 15 5.1 Determination of viscosity using 17 Red Wood Viscometer. v
  6. 6. LIST OF ABBREVIATIONS1. ASTM-American Society for Testing and Material Standard2. cSt-Centistroke3. FFA-Free Fatty Acid4. SBME-Soya Bean Methyl Ester vi
  7. 7. ABSTRACT Recently much effort has been focused on research and development of new types oflubricating oils to reduce wear, friction and corrosion in engine applications. Vegetable oils arebased on soya bean, sunflower, castor, rapeseed, corn, canola and soya bean. The vegetablelubricants are environmentally friendly alternative to mineral oils since they are biodegradable.The vegetable oils are having many advantages like high viscosity index, low friction coefficient,high flash point, low volatile etc., over mineral oils. Soya bean oil Methyl ester based biodiesel isa viable alternative to fossil fuels. Apart from its use as an alternative fuel, Soya bean oil methylesters have the potential to be used as lubricants due to its inherently favorable lubricity andviscosity index properties. vii
  8. 8. 1. INTRODUCTION “The important thing in science is not so much to obtain new facts as to discover new facts of thinking about them.” - SIR WILLIAM BIAGG1.1 NEED FOR ALTERNATE LUBRICANTS Historically, many mass and agricultural derived materials have been suggested asalternative energy sources and the use of biodiesel as fuel presents a promising potential. Thesesources are limited, and will be exhausted in the near future. . It has necessitated the governments, research communities, and private organizationsaround the world to look for alternative and renewable sources of energy due to the depletion ofpetroleum reserves, increase in energy demands, unpredictability of fossil oil production, andincreased concerns of rising greenhouse gas emissions. To date, many alternatives have beenresearched and demonstrated but only a few have been proven to be practically feasible in termsof availability, economics, public and environmental safety, and simplicity of use. One suchpossible alternative is biodiesel from vegetable oils, used at 100% or blended with diesel fuel forcompression-ignition type engines. Soya bean oil is relatively cheap when compared to mineral oils and other vegetable oils.In addition, soya bean oil is safer and environmentally friendly. Crankcase lubricants are eitherpetroleum based or mineral oil based. Prices of these synthetic oils are significantly highercompared to vegetable oil-based lubricants. Although soya bean oil and its derivatives likemethyl esters have many properties that are conducive as crankcase oils, in depth engine studieson the functionality of these oil forms are limited. viii
  9. 9. Use of bio based lubricants is expected to increase in next five to ten years due togrowing regulatory concerns on existing lubricants. Most of the synthetic lubricants in presentmarket are made of esters and offer better thermal and oxidative stability. As esters can bemanufactured from vegetable oils by transesterification, lubricants can be potentiallymanufactured from vegetable oils.1.2 LUBRICATING OIL The main purpose of lubricants is to lubricate moving parts of the vehicle to reducefriction and wear and tear by providing smoothing, trouble free performance for increased lengthof time. Because heat and wear are associated with friction, both effects can be minimized byreducing the coefficient of friction between the contacting surfaces. Lubrication is also used toreduce oxidation and prevent rust; to provide insulation in transformer applications; to transmitmechanical power in hydraulic fluid power applications; and to seal against dust, dirt, and water. The primary objectives of the lubricants in automobiles are to reduce wear and frictionbetween moving parts, to act as cooling medium for removing heat, to keep the engine partsclean especially piston rings and ring grooves, oil ways and filters. It also forms a good sealbetween the piston rings and cylinder walls and absorbs and carries away harmful substancesfrom incomplete combustion. To prevent metallic components from corrosive attack by the acidformed during the combustion process. It should also resist oxidation which causes sludge andlacquers. ix
  10. 10. 2. PROPERTIES OF LUBRICATING OIL There are various properties that determine the quality of lubricating oil; the mostimportant one is the viscosity (measure of resistance to the flow of oil) of the oil and the variousother parameters that govern the quality of the oil are2.1 Flash Point The lowest temperature at which the lubricating oil will flash when a small flame isintroduced across its surface.2.2 Fire Point When the oil is heated beyond the flash point, the minimum temperature at which the oilwill burn continuously.2.3 Cloud Point The oil changes from liquid state to solid state or a plastic state when subjected to lowertemperatures, in some cases the oil starts solidifying which may appear cloudy known as thecloud point2.4 Pour Point The lowest temperature at which the lubricating oil will pour. The pour point of oil is theindication of its ability to move at lower temperatures.2.5 Specific Gravity The specific gravity is the measure of density of the oil which is measured using ahydrometer that is made to float in the oil.2.6 Sulphur Content If the sulphur content is present in considerable amount in the lubricating oil then itpromotes corrosion. The corrosion shows the amount of sulphur content. x
  11. 11. 2.7 Adhesiveness It is the property of the lubricating oil due to which the of particles stick to the metalsurfaces.2.8 Kinematic Viscosity Kinematic viscosity may be defined as the quotient of the absolute viscosity incentipoises divided by the specific gravity of a fluid, both at the same temperature. The unit ofkinematic viscosity is stoke or centistokes (1/100th of a stoke). Viscosity of engine oil is one of its most important and most evident properties. Forengine oil, a small change in viscosity with temperature (high viscosity index) is desirable toprovide a wide range of operating temperatures over which given oil will provide satisfactorylubrication. A high viscosity implies high resistances to flow while a low viscosity indicates a lowresistance to flow. Viscosity varies inversely with temperature. Viscosity is also affected bypressure; higher pressure causes the viscosity to increase, and subsequently the load-carryingcapacity of the oil also increases. This property enables use of thin oils to lubricate heavymachinery.2.9 Viscosity Index (VI) Viscosity Index is an arbitrary number used to characterize the variation of the kinematicviscosity of a fluid with change in temperature. Viscosity index can be classified as follows: lowVI - below 35; medium VI - 35 to 80; high VI - 80 to 110; very high VI - above 110. The higherthe viscosity index, the smaller the relative change in viscosity with temperature. Therefore, a fluid that has a high viscosity index can be expected to undergo very littlechange in viscosity with temperature extremes and is considered to have a stable viscosity. A xi
  12. 12. fluid with a low viscosity index can be expected to undergo a significant change in viscosity asthe temperature fluctuates. Oil with a VI of 95 to 100 would change less than one with a VI of80.2.10 Volatility It is the ability of any fluid to change from its physical state of liquid to vapor at elevatedtemperatures. Volatility characteristics are essentially inherent in the choice of base stock oil fora particular type of service. Viscosity gives an indication of the volatility of a lubricant ingeneral, the lower its viscosity the higher its volatility. Table 2.1 Desired Properties of Lubricants Properties Requirements Kinematic viscosity at 40 deg. C Low Kinematic viscosity at 100 deg. C Low Viscosity index High Total acid number Low (mg-KOH/gm) Saponification valve High (mg-KOH/gm) Pour point (deg. C) Low Flash point (deg. C) High Iodine value Low xii
  13. 13. 3. SCOPE OF THIS PROJECT Soya Bean Methyl Ester (SBME) is a viable alternative to fossil fuels. Apart from its useas an alternative fuel, soya bean oil methyl esters have the potential to be used as lubricants dueto its inherently favorable lubricity and viscosity index properties While using the esters of vegetable oil, still some limitations prevail such as lowoxidation stability, low thermal stability, low temperature, etc. On the other hand, the oxidationof vegetable oil is a main problem encountered when it is used as a lubricant in engines.Generally the thermal stability will improve to some extent when the ester of vegetable oil fromtrans-esterification process and it is clearly studied later. xiii
  14. 14. 4. VEGETABLE OILS AND ESTERIFICATION4.1 INTRODUCTION Vegetable oils are a viable and renewable source of environmentally favorable oils.Recently, much effort has been focused on research and development of new types of lubricatingoil additives to reduce wear and friction in the tribological systems. It has been noted that the useof additives to improve the lubricating capacity and durability of oil plays an important role inthe wear and friction process of materials.4.2 PRODUCTION OF SOYA BEAN METHYL ESTER Generally, there are three basic ways for the production of methyl esters from oils andfats:  Base catalyzed transesterification of the oil (triglycerides) with methanol;  Direct acid catalyzed esterification of the free fatty acids (FFA) with methanol;  Conversion of the oil to FFA followed their esterification as described above.The majority of the methyl esters are produced using the base catalyzed reaction because it is the  Most economic for several reasons  Low temperature and pressure  High yields and short reaction times  Direct conversion process xiv
  15. 15. 4.2.1 TRANSESTERIFICATION PROCESS Transesterification is the process of using an alcohol (e.g., methanol or ethanol) in thepresence of a catalyst, such as sodium hydroxide or potassium hydroxide, to chemically breakthe molecule of the raw renewable oil into methyl or ethyl esters of the renewable oil withglycerol as a by-product which is described in Figure 3.4. A catalyst is always added to thetransesterification system to improve the reaction rate. Transesterification consists of a number of consecutive, reversible reactions. Diglyceridesand monoglycerides are the intermediates in this process. The triglyceride is converted stepwiseto Diglycerides, monoglycerides and finally glycerol. The reactions are reversible, although theequilibrium lies towards the production of fatty acid esters and glycerol. A little excess ofalcohol is used to shift the equilibrium towards the formation of esters. In presence of excessalcohol, the foreword reaction is pseudo-first order and the reverse reaction is found to be secondorder. It was also observed that transesterification is faster when catalyzed by alkali.Transesterified renewable oils have proven to be a viable alternative diesel engine fuel withcharacteristics similar to those of diesel fuel. The need for going to Ester is due to its betterViscosity Index, Thermal Stability and Oxidation Stability than that of Crude Oil. Fig 4.1 Transesterification reaction xv
  16. 16. 4.2.2 MATERIALS REQUIRED The materials required for the preparation of Soya bean Methyl Ester are listed below.  Soya bean oil  Separating funnel  Heater and Thermometer  Alcohol (methanol/ethanol)  Beaker and Measuring flask  Catalyst (NaOH/KOH)  Agitator  Air pump4.2.3 METHOD ADOPTED Have all the materials warm, room temperature at the coolest, 130°F at the warmest. Puton the respirator, goggles, and gloves. Place 1fluid cup of methanol in the blender. Measure out3.5 grams of sodium hydroxide from a new container and place it in the methanol in the blender.Put the top on the blender and blend on low speed for about five minutes. Shut off the blender.The mixture in the blender is now sodium methoxide, a strong base. Avoid getting this onanything, especially yourself. Measure one quart of new Crude Soya bean oil and pour it into the sodium methoxide inthe blender. Put the lid on and blend at low speed for half an hour. Let the mixture settle atroom temperature for at least eight hours. The mixture is now composed of light-colored methylesters floating on top of heavier, darker glycerol. Using the hand pump, pump the light biodieseloff the glycerol. xvi
  17. 17. Fig 4.2 Preparation of sodium methoxide solution & adding it to oil4.2.4 SOAP FORMATION xvii
  18. 18. 4.2.5 SEPARATION & DRAINING OF GLYCEROL Fig 4.3 Separation & Draining of Glycerol xviii
  19. 19. 4.3 WASHING PROCEDURE4.3.1 Significance of washing The Methyl ester produced with the process described above will work in some heatingand lighting equipment and may be used as a lubricant for diesel engines. Most impurities settleout into the glycerol layer including unfiltered particulates, methanol, and glycerin. Somesources encourage using unwashed Methyl ester, because washing Methyl ester is a time-consuming process. However, some alcohol, sodium hydroxide, and soap remain suspended throughout thebiodiesel after the transesterification is complete. Water in Methyl ester can lead to biologicalgrowth as the fuel degrades. Unreacted methanol in the Methyl ester can result in explosion andcan corrode engine components. The catalyst, sodium hydroxide, can also attack other enginecomponents. Since the methanol and sodium hydroxide are chemical bases, unwashed biodieselis caustic and may damage diesel engine components. Soap is not a fuel and will reduce fuellubricity and cause injector coking and other deposits.4.3.2 Removal of Unreacted methanol Unreacted alcohol may be distilled from the Methyl ester and reclaimed for use in futurebatches. Although alcohol reclamation is beyond the scope of this publication, note thatmethanol boils at 148°F at sea level. Methanol can be driven from biodiesel by heating it; dothis outside or vent the methanol to the outside. Never breathe methanol fumes. A much betterand safer solution is to use a vacuum pump to lower the pressure of a closed tank. The methanolcan be collected and re-used. See the Resources section on methanol reclamation. xix
  20. 20. Fig 4.4 Removal of unreacted methanol4.3.3 Washing Techniques There are three techniques for washing the Ester Agitation washing, Mist washing, andBubble washing. The process of washing Methyl Ester involves mixing it with water. Water is heavier thanMethyl Ester and absorbs the excess alcohol, sodium hydroxide, and soap suspended in it. Afterwashing and settling, the water and the impurities in the water can be drained from the bottom ofthe container. Several wash cycles are generally needed. The first water drained off the bottomof the Methyl Ester will be milky, and the final wash water drained off will be clear. Excesssodium hydroxide in the Methyl Ester will form soap when mixed with water, and it takes awhile for the soap to settle out. Depending on the method you use, it takes roughly as muchwater as Methyl Ester for a wash cycle. xx
  21. 21. Fig 4.5 Washing Techniques Initial washings must involve gentle mixing to minimize the formation of soap that willtake time to settle out. However, you want the mixing to be thorough and for the water to bedispersed throughout the Methyl Ester.Agitation washing amounts to stirring water into the Methyl Ester, letting it settle, and draining itoff. Mist washing is spraying a fine mist of water over the surface of the Methyl Ester. Tinydroplets of water fall through the Methyl Ester and pick up impurities on the way down. Bubble washing is done by putting a bubbler in a layer of water beneath the Methyl Esterin a container. As the bubbles rise they are coated with water, which picks up impurities as ittravels up and then back down through the Methyl Ester. xxi
  22. 22. 4.3.4 Washing Technique adopted The washing technique here adopted is Agitation washing. Pour 1 liter of Methyl Esterinto a 2-liter plastic soft drink bottle. Gently pour about 500 milliliters of lukewarm water intothe bottle. Seal with a cap that will not leak. Gently rotate bottle end for end for about 30seconds. After 30 seconds place the bottle upright. If you have been Gentle, the water andMethyl Ester will separate immediately. You will notice the water is not clear. Wearing rubbergloves, remove the cap, and using your thumb as a valve, turn the bottle upside down and drainthe water. Drain the water into a bucket and allow it to evaporate. Fig 4.6 Washing Technique Adopted (Agitation Washing) xxii
  23. 23. Discard any residue. Repeat the process of adding 500 milliliters of lukewarm water,gently shaking, and draining off the water four or five times. Each time that you repeat theprocess, you should shake the mixture a little more vigorously and for a little longer, until bythe fifth washing you are shaking the mixture very strongly for about a minute or a little more.Washed Methyl Ester is very cloudy, much lighter in color than the original Methyl Ester, andlooks terrible. After a day or two of settling and drying it will clear.4.3.5 Drying of washed Methyl Ester After the Methyl Ester is washed, it should be dried until it is clear. This can be done byletting the Methyl Ester sit (covered) in a sunny location for a few days, or it may be heated toabout 120°F for a few hours. Reacted, washed, and dried Methyl Ester may be used in any dieselengine. It should have a pH of close to 7, or chemically neutral and it should have no methanolleft in it. xxiii
  24. 24. 5. DETERMINATION OF VISCOSITY The Kinematic Viscosity of the oil samples was determined with a Redwood Viscometerat temperatures ranging from 40°C to 100°C. Fig 5.1 Determination of viscosity using Red Wood viscometer. xxiv
  25. 25. Kinematic Viscosity was estimated by means of the following equation: Kinematic Viscosity = [At – (B/t)] (5.1) Where A & B are Constants t – Redwood seconds Table 5.1 Kinematic Viscosity of some oil samples Kinematic Viscosity (Centistokes) Crude Soya bean oil Soya bean Methyl Ester 40°C 100°C 40°C 100°C 31.19 7.4 8.57 2.91 xxv
  26. 26. 6. DETERMINATION OF VISCOSITY INDEX Viscosity Index is a measure of a fluids change of viscosity with temperature. The higherthe viscosity index, the smaller the relative change in viscosity with temperature. The ViscosityIndex was calculated for the samples crude and esters of Soya bean oil from Kinematic Viscosityat 40°C and 100°C as per ASTM Standards D 2270 – 93 From ASTM Standards, the formula used to calculate the Viscosity Index of the oil isgiven in the Equation VI = [((antilog N) - 1) / 0.00715] +100 Where N = (log H – log U) / log Y Y = kinematic viscosity at 100°C of the oil whose kinematic Viscosity is to be calculated, mm2/s (cSt) H = kinematic viscosity at 40°C of an oil of 100 viscosity index having the same kinematic viscosity at 100°C as the oil whose viscosity index is to be calculated mm2/s Table 6.1 Calculation of Viscosity Index Crude soya bean oil SBMETable Values from Standards H 52.88 11.50Kinematic viscosity at 40°C U 31.19 8.57Kinematic viscosity at 100°C Y 7.4 2.91 LogH – LogU 0.229276 0.127717 Log Y 0.869232 0.463893 N 0.263768 0.275316Viscosity Index VI 216.86 223.77 xxvi
  27. 27. 7. RESULTS OF THE LUBRICANT PROPERTIES Table 7.1 Results of the lubricant properties Parameters Soya bean oil Soya bean methyl esterKinematic viscosity at 40 deg. C 31.19cSt 8.57cStKinematic viscosity at 100 deg. C 7.4cSt 2.91cStViscosity index 216.86 223.77 xxvii
  28. 28. 8. CONCLUSION The vegetable oils are having many advantages like high viscosity index, low frictioncoefficient, high flash point, low volatile etc., over mineral oils, used as base stock for lubricants.However, due to their low thermal and oxidative stabilities, their usage in engine applications islimited. The chemical modification of the oil forms via. esterification reduces viscosity,increases the viscosity index, and improves the thermal/ oxidation stability by reducing the polyunsaturated fatty acids. In this project work Soya bean oil is considered as a potential candidate for bio-lubricantbase stock based on the availability. The transesterification of Soya bean oil with alcohol(Methanol) in the presence of base catalyst (NaOH) yielded Soya bean Methyl Ester (SBME)which has superior thermo-oxidative properties than crude soya bean oil. Hence, it is concluded that the ester forms of vegetable oils can be blended with mineraloil for crankcase lubrication. Also, esters produced with higher order alcohols along withsuitable bio-degradable additives will replace the mineral / synthetic lubricants for engineapplications. The future research may be in the areas of esterification of vegetable oils with higherorder alcohols, bio-degradable additives, and condition monitoring analysis of mineral oil-esterblends. xxviii
  29. 29. 9. REFERENCES1. Aggarwal, J.S. and Verman, L.C. (1940), ‘Vegetable oils as lubricants’, Indian Ind. Research Bull, Vol.18, pp. 5-25.2. American Society for Testing & Materials standards3. Fernando, S. and M. Hanna (2001), ‘Comparison of viscosity characteristics of soybean oils with a mineral oil two-stroke engine lubricant’, Transactions of the ASAE.4. Schuchardt, U., Sercheli, R. and Vargas, R.M. (1998), ‘Transesterification of vegetable oils: a review’, Journal of Brazil Chemical Society, Vol. 9, pp.199– 210.5. Van Gerpen J. (2005), ‘Biodiesel processing and production’ Fuel Process Technology Vol.86, pp.97–107. xxix