Continuous Production Of Biodiesel In A Micro-channel Reactor

With the aggravation of the energy crisis, biodiesel has been got more attention from the world as an environmental friendly alternative fuel. Biodiesel is produced from methanol and oil catalyzed by acid/base or lipase, but mass transfer is one of the key problems due to the insolubility of methanol and oil. Generally the production of biodiesel is carried out in a stirred reactor through a batch mode and the productivity is relatively low. Micro-channel reactor is a new type of rector with enhanced mass transfer and heat transfer, and was applied in the study of biodiesel synthesis. In this thesis the micro-channel reactor with a combination of micromixer and microreaetor was studied in continuous production of biodiesel.Firstly, a new type of micro-channel reactor was designed and constructed based on previous study of microrectors and literature of biodiesel study which consists of micromixer and microreaetor. The effect of channel shape on biodiesel synthesis was studied. The yield of biodiesel using a "Z"-microreactor is1.11fold of that obtained with a "U"-microreaetor. Then the effect of molar ratio of methanol to oil. temperature, catalyst content and residence time on the yield of biodiesel were studied using the "Z"-microreactor. A yield of98.6%was obtained when the reaction was performed at58℃with a molar ratio of8, residence time of15s under the catalysis of KOH (1.2%weight of oil),The reaction condition was optimized using the response surface method (RSM) and minitab was used for data analysis. The optimal condition of biodiesel production was8.5:1of molar ratio of methanol to oil,59℃,1.17%KOH (weight of oil) and14.9s of the residence time, and the yield of biodiesel was99.5%. Under this condition the quality of soybean oil on biodiesel production was explored. The biodiesel yield was decreaed when the content of water and oleinic acid in oil was increased, and fatty acid showed a strong impact.Finally, biodiesel synthesis catalized by Novozymes435in a micro-channel reactor was explored with/without tert-butyl alcohol as solvent. The results showed that the yield of biodiesel increased in the two systems with the elongation of reaction time, and the yield is higher when solvent used.