Comparison of Pyrolysis of Jatropha Cake with Different Catalysts Using PY-GC/MS

Abstract

In this work, effect of different zeolite catalysts that reacted with jatropha cake residue to give pyrolysed products was studied. The products were separated and characterised by using pyrolysis gas chromatography-mass spectrometry (PY-GC/MS). A 4.0 mg of jatropha sample was put into the capsule sample holder of the pyrolysis-GC-MS instrument and the pyrolysis was performed at 500°C. Two separate experiments were carried out. In the first experiment the catalysts were Mordenite zeolite (30 mol/mol ratio of SiO2/Al2O3), Beta zeolite (37 mol/mol ratio of SiO2/Al2O3) and Pd/Al2O3. Each catalyst was mixed with jatropha cake with a ratio of 1:1 by weight. The jatropha cake pyrolysed with Mordenite zeolite gave the highest amount of aromatic hydrocarbons and the lowest amount of fatty acids than the products obtained from the other zeolites. In the second experiment, the amount of Mordenite zeolite was optimised for maximum production of aromatic hydrocarbon. The jatropha cake was mixed with increasing ratios of Mordenite zeolite of 1:2, 1:3 and 1:5 by weight. Improving the ratio of the zeolite increased the amount of aromatic hydrocarbon, while the yield of phenol and fatty acids components significantly decreased. To study the interrelation effect between two catalysts to the pyrolysis of jatropha cake, Mordenite zeolite and Pd/Al2O3, were mixed with different ratios of 1:1, 2:1 and 3:1 by weight, and the jatropha cake was pyrolysed with the mixed catalyst at the ratio of 1:1. Increasing the ratio of Mordenite zeolite in the mixed catalyst gave similar effect to those without Pd/Al2O3, except that the phenol component in the product reduced. To obtain the highest yield of desirable components, namely aromatic and aliphatic hydrocarbons, Mordenite zeolite was proved to be the most suitable catalyst with the ratio of 1:5 by weight.