Hydrocarbon fuels from gas phase decarboxylation of hydrolyzed free fatty acid

Abstract

Gas phase decarboxylation of hydrolyzed free fatty acid (FFA) from canola oil has beeninvestigated in two fix-bed reactors by changing reaction parameters such as temperatures,FFA feed rates, and H2-to-FFA molar ratios. FFA, which contains mostly C18 aswell as a few C16, C 20, C22, and C24 FFA, was fed into the boiling zone, evaporated, carriedby hydrogen flow at the rate of 0.5-20 ml/min, and reacted with the 5% Pd/C catalystin the reactor. Reactions were conducted atmospherically at 380-450 °C and the products,qualified and quantified through gas chromatography-flame ionization detector(GC-FID), showed mostly n-heptadecane and a few portion of n-C15, n-C19, n-C 21, n-C23 as well as some cracking species. Results showed that FFA conversion increased withincreasing reaction temperatures but decreased with increasing FFA feed rates and H2-to-FFA molar ratios. The reaction rates were found to decrease with higher temperatureand increase with higher H2 flow rates. Highly selective heptadecane was achieved byapplying higher temperatures and higher H2-to-FFA molar ratios. From the results, ascatalyst loading and FFA feed rate were fixed, an optimal reaction temperature of 415 °C as well as H2-to-FFA molar ratio of 4.16 were presented. These results provided goodbasis for studying the kinetics of decarboxylation process. © 2012 American Society of Mechanical Engineers.