HTLCs-M Microstructure Design And Catalyst Activity Of The Preparation Of Biodiesel By Using Microalgae Oil

Traditional fossil fuels increasingly drying up, gradually intensified greenhouse effect and increasing energy costs and other reality conditions forced people to speed up the search and development the new energy which clean, efficient and renewable energy to replace fossil fuel energy. Biodiesel as a new renewable biofuels, because of its high oxygen content, burning full, biodegradable, environmental friendly and other advantages have receive heavy attention. Biodiesel industrialization mainly chance homogeneous catalyst, how this kind of catalyst showed high catalytic activity under mild reaction conditions, but homogeneous base catalyst for demanding raw material pretreatment, catalyst and product separation difficulties, the product post-processing generate a large amount of waste acid/alkali, pollute the environment in the use process. In order to reduce the production cost of biodiesel, difficulty of product separation, development of low cost, high efficiency, re-used good, stable properties of solid base catalysts is a hotspot of current research.In this paper, the preparation of the two kinds of new type solid alkali catalyst, used in catalytic microalgae oil and methanol to make ester exchange reaction of the preparation of biodiesel.Through the supersaturated coprecipitation, transition metal zinc doping in Ca Mg Al-LDHs hydrotalcite solid base catalyst, make new solid base catalyst Zn/Ca Mg Al-LDHs. By Thermal Analysis(TG-DSC), X-ray Diffraction(XRD), Scanning Electron Microscope(SEM) and Chemical Adsorption(CO2-TPD) and so on for characterization the structure of the catalysts. Through the characterization of catalyst structure and catalytic activity evaluation, studies the relationship between catalyst structure and catalytic performance, research has shown that Zn/Ca Mg Al-LDHs has typical hydrotalcite layered structure, specific surface area increased significantly after 450 ℃ roasting, and used in microalgae oil with methanol catalyzed reaction of preparing biodiesel has high catalytic activity. Combination of exchange reaction conditions optimization results show that the doping amount of Zn2+ is 12 %, reaction temperature 65 ℃, reaction time is 4 h, n(methanol) : n(microalgae oil) = 14 : 1, m(12Zn-LDHs) : m(microalgae oil) = 4 %, biodiesel yield up to 94 %, and the re-used is good. It is worth noting that the Zn/Ca Mg Al-LDHs has good acid resistance and water resistance when the reaction system of the water content is 13 %, the FAA content as high as 15 %, the biodiesel yield remains above 85 %.Through the supersaturated coprecipitation, transition metal Ni doping in Ca Mg Al-LDHs hydrotalcite solid base catalyst, make new solid base catalyst Ni/Ca Mg Al-LDHs, and the structures were characterized, and the influence of the biodiesel yield(%) were studied which include the Ni2+ load(%), the molar ratio of methanol and microalgae oil, reaction time(h), catalyst dosage(%), and the reaction temperature(℃). The research results show that when the doping amount of Ni2+ is 12 %, Ni/Ca Mg Al-LDHs owns highest catalytic activity; When the molar ratio of methanol and microalgae oil is 12:1, and catalyst dosage is 3% of the microalgae oil quality, 65 ℃ reaction 3 h, biological diesel oil yield up to 96 %, and re-used good, after re-used 7 times, biodiesel yield is still higher than 83 %.