Process conditions of preparing biodiesel by using mixed liquor of waste cooking oil and methanol/ethanol

In this paper, the process and mechanism of preparation of biodiesel by using waste cooking oil as raw material, mixed liquor of methanol/ethanol as ester exchange agent and P-toluene sulfonic acid as catalyst were studied. This experiment showed that the optimum technological conditions was as follows: molar ratio of alcohol/oil was 10/1, molar ratio of methanol/ethanol was 7/3, the weight ratio of catalyst to waste cooking oil was 8%, reaction time was 2 h, and reaction temperature was 80. Under this condition, the biodiesel yield can reach 97.2% by measuring the glycerol content. The research found that the mixed liquor of methanol/ethanol took on a good synergy effect as ester exchanger. The addition of ethanol had solved the problem of the poor solubility of methanol in oil. Meanwhile, the methanol alleviated the emulsification of ethanol in the reaction process, thus the yield of biodiesel was improved significantly. After testing the performance indicators of homemade biodiesel, the results showed a high purity of biodiesel and the key performance indicators matched the biodiesel national standards. ©, 2015, Editorial Department, Chinese Cereals and Oils Association. All right reserved.