Effects of water on the esterification of free fatty acids by acid catalysts

Ji-Yeon Park, Zhong-Ming Wang, Deog-Keun Kim and Jin-Suk Lee

Renewable Energy, 2010, vol. 35, issue 3, 614-618

Abstract: To maximize the production of biodiesel from soybean soapstock, the effects of water on the esterification of high-FFA (free fatty acid) oils were investigated. Oleic acid and high acid acid oil (HAAO) were esterified by reaction with methanol in the presence of Amberlyst-15 as a heterogeneous catalyst or sulfuric acid as a homogeneous catalyst. The yield of fatty acid methyl ester (FAME) was studied at oil to methanol molar ratios of 1:3 and 1:6 and reaction temperatures of 60 and 80°C. The rate of esterification of oleic acid significantly decreased as the initial water content increased to 20% of the oil. The activity of Amberlyst-15 decreased more rapidly than that of sulfuric acid, due to the direct poisoning of acid sites by water. Esterification using sulfuric acid was not affected by water until there was a 5% water addition at a 1:6 molar ratio of oil to methanol. FAME content of HAAO prepared from soapstock rapidly increased for the first 30min of esterification. Following the 30-min mark, the rate of FAME production decreased significantly due to the accumulation of water. When methanol and Amberlyst-15 were removed from the HAAO after 30min of esterification and fresh methanol and a catalyst were added, the time required to reach 85% FAME content was reduced from 6h to 1.8h.

Keywords: Soapstock; Esterification; Water production; Amberlyst-15; Sulfuric acid (search for similar items in EconPapers)
Date: 2010
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Citations: View citations in EconPapers (13)

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Persistent link: https://EconPapers.repec.org/RePEc:eee:renene:v:35:y:2010:i:3:p:614-618

DOI: 10.1016/j.renene.2009.08.007

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