Hydrocarbon Fuels From Gas Phase Decarboxylation of Hydrolyzed Free Fatty Acid

摘要

Gas phase decarboxylation of hydrolyzed free fatty acid (FFA)from canola oil has been investigated 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 C_(18) as well as a few C_(16),, C_(20), C_(22), and, C_(24) FFA, was fed into the boiling zone, evaporated, carried by hydrogen flow at the rate of 0.5-20 mllmin, and reacted with the 5% Pd/C catalyst in 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 ofn-C_(15), n-C_(19), n-C_(21), n-C(23) as well as some cracking species. Results showed that FFA conversion increased with increasing reaction temperatures but decreased with increasing FFA feed rates and H_2-to-FFA molar ratios. The reaction rates were found to decrease with higher temperature and increase with higher H_2 flow rates. Highly selective heptadecane was achieved by applying higher temperatures and higher H_2-to-FFA molar ratios. From the results, as catalyst loading and FFA feed rate were fixed, an optimal reaction temperature of 415 ℃ as well as H_2-to-FFA molar ratio of 4.16 were presented. These results provided good basis for studying the kinetics of decarboxylation process.