Synthesis And Performance Of Biodiesel From Different Oils Using Lipase

Biodiesel, whose basis is fatty acid methyl ester, is a kind of clean fuel and also has the advantage of renewable, pollution free, biodegradable. This thesis works on the synthesis, performance testing and adjustion of biodiesel made from different oils using lipase as follows:1、This paper studied the synthesis of biodiesel from HC oil and acidificated oil in organic solvent system using immobilized lipase from Candida sp.99-125. The effect of various factors on reaction was studied, including the moler ratio, the nature of solvents, substrate concentration, pH, water content, reaction temperature and period, adding methanol and so on. Two optimum condition were obtained as following:using2g HC oil as raw material, using5ml n-hexane as the organic solvent, with the molar ratio of methanol and HC oil3:1, adding50%wt (percent of HC oil) lipase and5%wt water, adding methanol in separate three times, totally reacted12h under a temperature of38℃. As can be seen from the results, the conversion rate reached98%under the optimum conditions. Using2g acidificated oil as raw material, using2ml petroleum ether as the organic solvent, with the molar ratio of methanol and HC oil3:1, adding50%wt (percent of acidificated oil) lipase and15%wt water, adding methanol in separate three times, totally reacted12h under a temperature of40℃; the conversion rate reached97%.On the bases of the traditional process of biodiesel synthesis by immobilized lipase in organic solvent system, the methods of using biodiesel product as the solvent and using fermentation directly instead of immobilized lipase as catalyst were tried out. It’s proved that the conversion could be in the range of85%to92%and the content of biodiesel could reach95%. While the conversion would be more than96%using fermentation as catalyst.2、There are several characters which can not meet with the standards without treatment such as acid number, water content, cold filter plugging point (CFPP), oxidative stability. The processes of adjustion including neutralisation, washing, desiccation adding additives were estabilished. After a series of treatment, the acid number was down to0.8mgKOH/g from8-40mgKOH/g; the water content was no more than100ppm; the CFPP was decreased to-15℃from-2℃; the oxidation residue was reduced to2.2mg/100ml from12.8mg/100ml. These characters met with the EU standard through adjustion and the biodiesel was stable in application, transportation and storage.3、The composition and performance of the biodiesel catalyzed by immobilized lipase were tested. The emission characteristics, output power and fuel economic of a diesel engine were also studied. The purity of the product reaches97.8%. The Flash Point is above170℃. The Sulfur Content is below0.0005%. The Cetane Number is as high as73.6. The biodiesel,20%blends, produces28%and36%lower exhaust carbon monoxide and unburned hydrocarbons. The oxides of nitrogen decreases by24%, while the smoke emission decreases by0.2Rb to0.9Rb. The excellent quality of biodiesel is proved.