Supercritical Alcohol Technology in Biodiesel Production: A Comparative Study between Methanol and Ethanol

Abstract

A system for non-catalytic supercritical alcohol technology was developed using a batch-type tube reactor. In the present study, methanol and ethanol were used as the source of alcohol and a comparative study on the yields of supercritical methanol and supercritical ethanol was carried out. The effects of temperature, reaction time, and molar ratio of alcohol-to-oil on the yield of fatty acid methyl esters were investigated. The results obtained showed that supercritical methanol is superior to supercritical ethanol in terms of biodiesel yield and reaction time. Supercritical methanol reaction only required a mere 20 min of reaction time to achieve more than 72% yield of biodiesel while supercritical ethanol only can produce 65% for a longer period of 23 min. Nevertheless, the study has shown that supercritical alcohol reaction has significant advantages compared to conventional catalytic methods, such as lower reaction time and simpler separation and purification steps.

Keywords:

• alcohol
• biodiesel
• palm oil
• supercritical alcohol
• transesterification