The Exploration For Preparation Of Biodiesel With Green Technology

In this paper, the quality inferior process of cooking oil in high temperature and the relationship among the quality factors were investigated. Based on the former work and the collection of wasted, the researches processed included the pretreatment of raw wasted oil, the screening of based lipases, the immobilization procedure of the enzyme and its property, the technology comparison of normal catalysis with the immobilized enzymatic catalysis, and the tests of performance index of biodiesel prepared by the two methods. The new carrier for the enzyme was selected, and so did the immobilization method. The quality of biodiesel made by the enzymatic technique can satisfy the utilization requirement.The main conclusions were:1. The refined soybean oil could be treated as wasted oil cooking around 13h at 180℃, because its chemical-physical index are beyond the limits of State cooking oil standard. But its main components were still fat acids.2. The process of two-step, that is esterification and ester exchange was used to transform the high free acid oil to biodiesel. The optimized parameters to lower the acid value were obtained, and the acid value of the wasted oil could be reduced from the level of 117.21mgKOH/g to 2mgKOH/g.3. The process of membrane immobilization of lipase was studied using the konjac glucamannon as carrier by the method of package. And the optimized parameters were: the emusifier of SP-60 with the quantity of 0.6% of KGM used, the pH value adjusted to 11.0 by Ca(OH)2 liquid, the enzyme liquid with the quantity of 0.03ml/gKGM also used. The immobilized enzyme was air-dryed under low temperature, and its activity was 51.26U/g. The property of the immobilized enzyme was also studied as the optimized temperature 35℃-55℃, pH value 5.5 and 7.7 separately. The result observed by SEM showed that the package frame was dense and close.4. The optimized parameters to catalyse wasted cooking oil to biodiesel by the immobilized enzyme were made by the Quadratic Orthogonal Rorarional Regression Design and Response Surface Methodology, the reaction temperature 40.89℃-43.26℃, reaction time 13.08 h-13.79h, the ratio of quantity between methanol and oil 2.71-2.25, the amount of water 7.74%-9.68% added, the methanol added thrice.5. Basically, performance index of the biodiesel made by both enzymatic and chemical methods were in accordance with the standards of biodiesel executed nowadays in USA and EU. And the procedure to produce biodiesel by enzyme technique is feasible.