The Study Of Preparation Of Biodiesel With Waste Grease From Creature And Vegetable

Biodiesel, which is long-chain fat acid ester, is made from creatural and vegetable greasevia transesterification with mild alcohols. It is non-toxic, biodegradable, renewable, andfriendly to environment and is a kind of substitute for diesel fuel with good quality. In thiswork, it was investigated that the transesterification was catalyzed by solid catalyst to producebiodiesel from waste grease from creature and vegetable to diminish the cost of biodieselsynthesis, get rid of waste grease’s harm to environment and health of people, avoid difficultyin separating homogeneous catalyst from product and predigests liquid waste’s treatment.In this study, the solid acid, KHSO4, which was selected as solid catalyst, exhibited goodcatalytic activity and favorable stability. The optimum technical conditions oftransesterification with solid acid catalyst were to react at25:1mole ratio of methanol towaste grease from creature and vegetable and353K for10h with8%potassium bisulfate.Under this condition, the conversion efficiency of transesterification was87.12%and the acidvalue of product was0.91mgKOH/g. On the other hand, solid base catalyst which wascharacterized by means of IR and SEM was prepared with active carbon loaded with25%KOH, followed by heating at403K for2h. The lab-made solid base catalyst also showed goodcatalytic activity and favorable stability. The optimum technical conditions oftransesterification were to react at8:1mole ratio of methanol to waste grease from creatureand vegetable and333K for3.5h with3%solid base catalyst. Under this condition, theconversion efficiency of transesterification was91.54%and the acid value of product was0.81mgKOH/g.To make up shortage of acid/base catalyst, converting waste grease from creature andvegetable to biodiesel was tried in two-step way. The optimum esterification conditions offirst step were to react at17:1mole ratio of methanol to waste grease from creature andvegetable and348K for3h with1.5%solid acid catalyst. Under this condition, the conversionefficiency of esterification was99.15%and the acid value of product was0.93mgKOH/g.Thus, the two-step way can shorten reaction time, decrease energy consume, and extend the scope of the raw oil used to produce biodiesel with high yields.Moreover, suitable cosolvent was chosen and the effect of impurity of waste grease fromcreature and vegetable on the esterification and transesterification was considered. Accordingto the national diesel standard of China, the properties of product were tested and the resultarrived at biodiesel criterion.