biodiesel production from acidified oils via supercritical methanol通过超临界甲醇从酸化油生产生物柴油.pdf

Energies 2011, 4, 2212-2223; doi:10.3390/en4122212 OPEN ACCESS energies ISSN 1996-1073 /journal/energies Article Biodiesel Production from Acidified Oils via Supercritical Methanol Jincheng Ding 1,*, Benqiao He 2 and Jianxin Li 2 1 College of Chemical Engineering, Shandong University of Technology, Zibo 255049, China 2 State Key Laboratory of Hollow Fiber Membrane Materials and Processes, School of Material Science and Engineering, Tianjin Polytechnic University, Tianjin 300160, China; E-Mails: hebenqiao@ (B.H.); jxli0288@ (J.L.) * Author to whom correspondence should be addressed; E-Mail: djclj@126.com; Tel.: +86-533-2787337; Fax: +86-533-2783397. Received: 7 November 2011; in revised form: 30 November 2011 / Accepted: 6 December 2011 / Published: 14 December 2011 Abstract: In biodiesel production, the vegetable oil used as raw material for transesterification should be free of water and free fatty acids (FFAs), which may consume catalyst and reduce catalyst efficiency. In this work biodiesel was prepared from acidified oils (AO) through a supercritical methanol route, in which the esterification of FFAs and transesterification of glyceride with methanol occurred simultaneously. The effects of the mass ratio of methanol to AO, the operation temperature as well as the water content on the FFAs conversion and glycerol yield were investigated. The results indicated that the FFAs conversion for esterification under the condition of 1:1 methanol/oil ratio, 310 °C and