Continuous catalyst-free methanolysis and ethanolysis of soybean oil under supercritical alcohol/water mixtures
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- 作者：Ignacio Vieitez ; Camila da Silva ; Isabella Alckmin ; Gustavo R. Borges ; Fern ; a C. Corazza ; J. Vladimir Oliveira ; Maria A. Grompone ; Ivá ; n Jachmaniá ; n
- 关键词：Biodiesel ; Supercritical methanol ; Supercritical ethanol ; Methanolysis ; Ethanolysis
- 刊名：Renewable Energy
- 出版年：2010
- 出版时间：September 2010
- 年：2010
- 卷：35
- 期：9
- 页码：1976-1981
- 全文大小：670 K
文摘
This work investigates and compares the reaction performance of soybean oil transesterification under supercritical methanol and ethanol, in a continuous catalyst-free process, as a cleaner alternative to conventional chemically catalyzed process. Reactions were performed in a tubular reactor, at 20 MPa, with oil to alcohol ratio of 1:40, varying the temperature in the range from 250 °C to 350 °C, and at two levels of water concentrations, 0 and 10 wt % . Although both processes proceeded with a relatively high reaction rate, conversion achieved by methanolysis was higher than that obtained by ethanolysis. Water positively affected both process: higher ester content and triacylglycerols depletion occurred when 10 wt % water was used compared with anhydrous conditions. Temperature increase favored the conversion of soybean oil to the corresponding methyl or ethyl esters, although temperatures above 300 °C increased the fatty acid degradation degree, a phenomenon responsible for the low ester contents obtained at the highest temperatures and lowest flow rates studied.