Biodiesel Production By Enzyme Catalysis In Non-Aqueous Phase

Facing severe energy crisis and greenhouse, the scientists all around the world have been researching the environmental friendly and renewable energy. Biodiesel was one of those. The methods of Transesterification synthesized biodiesel were chemical method and biological method. Contrast to conventional chemical process, enzymatic production process presented many advantages such as simple technology, better reaction selectivity, lower energy consumed and less environmental pollution. Biological method was chose to prepare biodiesel in non-aqueous phase in this paper.Fatty acid composition of four plant oil were analyzed in this paper, and refined tea oil(specil product in Guangxi) and waste fried oil were selected as material to synthesize biodiesel with methanol by transesterification.Lipase OF was chose as catalyst after three free lipases were compared. Lipases were inactivated because of high polarity of methanol. The step batch added methanol must be adopted. The optimal reaction condition: solvent was n-hexane, methanol : oil(molar ratio)=1:1, methanol was injected every 12h, silica gel was added after reacted 1h, temperature of reaction was 40℃, the enzyme amount was 7%(wt. by oil), reacted 48h, the conversion got 94.5% at last. Catalyzed waste oil at the same condition, the conversion got 87.7%.The reaction conditions which influenced the catalyzed effect of Novozyme 435 were investigated, Such as molar ratio of alcohol and oil, short chain alcohol, organic solvent, reaction temperature, reaction time, and enzyme amount. It was discovered that enzyme would be quickly inactivated when the concentration of methanol beyond 32.0mL/L. Silica gels were added into reaction system to adsorb methanol, quickly decreased methanol concentration and protected enzyme, became "buffer bottle" of methanol; on the order hand, to adsorb glycerol produced from reaction, promoted transesterification, and to eliminate the transferred resistance of glycerol. The optimal reaction condition: solvent was the petrol ester, methanol : oil (molar ratio)=3 : 1,...