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The world is confronted with the double crises of energy depletion and environmental degradation. Finding the substitute energy resources actively that environmental friendly and renewable become to the focus all of the world, and among the numerous engine substitute fuels, the biodiesel is the very improving one which has excellent emission and power performance and can be used in diesels directly without modifying.The traditional transesterification is the main method for biodiesel producing, but it has several disadvantages just like equipment corrosion, complex process, high energy consumption, secondary pollution of environment and byproduct losing, and the cost of biodiesel is the main obstruction for its applying. The plentiful waste oils and wild oils turn into the most improving raw materials for biodisel producing, but they must be esterification firstly because of their high acid value, the research about this is few, if the esterification reaction is catalyzed by strong acid （as sulfuric acid）, the disadvantages of traditional method are also exist.Aiming at these problems, we use the patent of our laboratory ’circulating gaseous esterification and transesterification and water vapour distillation’, take several kinds of cheap and high acid value oils （as rubber-seed oil, Jatropha curcas oil and waste oil） as the raw materials to producing biodiesel, we study on the catalysts of gaseous esterification and transesterification (they are sulfuric acid, Fe3+ /SO42- solid acid, P-toluene sulphonie acid in esterification reaction and potassium hydroxide, barium hydroxide, LDH/LDO solid alkali in transesterification reaction), and put forward the optimal reaction conditions and technology process according to the catalytic results and the reaction flow. Besides this, we also do some research in glycerin recycle and purification to cut down the cost of biodiesel. The conclusions are as follow:I The final technology flow is that esterification reaction is catalyzed by sulfuric acid, and transesterification step is catalyzed by barium hydroxide, except for the advantages of ’circulating gaseous esterification and transesterification and water vapour distillation’, it also has two benefits, the one is predigesting the process of biodiesel production, the recycle of byproducts and catalysts, under the condition of high biodiesel quality, the other is using the acidity waste water of esterification step to dispose transterification reaction, so it can "use the waste to control waste, change the waste to useful", and all the process is cleanable;II Establish the analytical method of glycerin content in biodiesel, and it can’t only be used in analyzing the glycerin content in biodiesel, but also in many raw materials. This
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