Studies on cracking of Jatropha oil

摘要

Pyrolysis/cracking of non-edible plant seed oil Jatropha oil (JO) and the utilization of cracked liquid product as a transportation fuel have gained importance due to the growing demand of renewable fuel oil source and depleting fossil fuel reserves. Thus, an attempt has been made to study the non-isothermal kinetics of JO cracking/pyrolysis using thermogravimetric analysis. The experiments were carried out at different heating rates of 5,10,15 and 20 K min~(-1) under nitrogen atmosphere from ambient temperature to 1073 K. The degradation of JO was found to occur in three steps. The main devolatilization of JO occurs in the temperature region 623-753 K and the degradation is essentially complete in this zone. Kinetic studies using isoconversional Friedman's plots obtained for JO degradation show the presence of two regions of JO degradation. The average activation energy calculated for the first region was 114.49 kj/mol and for the second region was 221.88 kj/mol. For better understanding of JO cracking, the cracking of JO was also carried out in a batch reactor and the liquid, gaseous product and char obtained were analyzed. Both the methods revealed that there is a complete conversion of JO. The liquid product obtained from JO cracking was found to contain alkanes, alkenes, cycloalkanes and carboxylic acids. The gaseous product obtained consisted of methane, pentane, iso-butane and certain uncondensed components (greater than C5 carbons). The char obtained had high carbon content and showed the presence of K, Mg, and Fe.