The Research Of Biodiesel Production With Calcium Base Solid Base Catalyst By Using Microalgae Oil

Biodiesel is a kind of preferred high-grade fuel, because compared with petroleum and diesel it has a higher oxygen content, which could reduce the emissions of CO2, SOx, CO,sulfur, hydrocarbons, aromatic compounds and smoke from diesel engine, and the environmental pollution caused by greenhouse effect.In this paper, calcium magnesium aluminum hydrotalcite was prepared by coprecipitation method, used as precursor to prepare calcium magnesium aluminum composite oxide by roasting, Hydrotalcite-like compounds have been widely studied as catalyst or catalyst precursor for transesterification of soybean oil with methanol to produce biodiesel.In the industrial production, fatty acid methyl ester(biodiesel) and glycerin are made by transesterification of fatty acid glyceride of vegetable oils or animal fat with methanol in the presence of NaOH or other homogeneous base catalysts. These catalysts are very cheap and effective, but it is very complicated to remove them thoroughly from the product by washing and easy to cause saponification, making the separation of biodiesel and glycerol difficult and producing large amounts of waste liquid in the washing process. At present, most of solid base catalysts have high reaction rate, which are developed to produce biodiesel, their products are easily separated, and catalysts with no pollution to the environment can be reused.(1)Firstly, the effects of reaction conditions for preparation of magnesium aluminum hydrotalcite like compounds of calcination temperature, alkalinity, alkaline earth metal content, alcohol-oil ratio and reaction temperature. When the catalyst was calcined at400℃, Ca-Mg-Al ratio of 1.5:4.5:2, Alcohol oil ratio of 14:1, the catalyst loading of 4.5wt%,the reaction temperature is 65℃, the reaction time is 5h, the highest conversion rate of 93%.The catalyst were characterized and analyzed by XRD, TG-DTG, CO2-TPD, BET, FT-IR,SEM and so on, and the effects of introduction of calcium ion on basicity of the catalyst,specific surface area and the performance of ester exchange reaction were studied.(2)Extraction of raw material of biodiesel from microalgae, and the esterification reaction of solid base catalysts in the acid value is less than 2.0mgKOH/g, While the oil acid value is higher than the value of microalgae, in the transesterification of microalgae oil pre esterification reaction. Removal of acid conditions: the temperature at 65, the mixed solution of constant temperature after adding 98% methanol and concentrated sulfuric acid,methanol was added into heavy oil 10wt%, After 2 hours the reaction stopped, finally,washed with distilled water and separation.