Co-pyrolysis of crude palm oil and polypropylene in a stirred tank reactor to produce non-oxygenated bio-oil

Abstract

Catalytic co-pyrolysis of crude palm oil (CPO) and polypropylene (PP) has been carried out in a stirred tank reactor to produce bio-oil at heating rate of 10 °C/min and maximum pyrolysis temperature of 550 °C with a nitrogen gas flow rate of 100 mL/min. Catalyst of ZrO2/α-Al2O3-TiO2 was used and prepared through calcination at heating rate of 7 °C/min with the maximum temperature of 1150 °C. Catalyst as much as 15% of the total feed was used. Composition of CPO and PP was varied and it was found that the feed containing 50%PP achieved the highest yield of bio-oil in which the bio-oil contains 81% volume of hydrocarbons based on GCMS spectroscopy measurement. Using pyrolysis feed containing 50% PP, compared to non-catalytic co-pyrolysis, catalytic co-pyrolysis produces nearly twice yield of bio-oil. The H-NMR and C-NMR analysis shows that bio-oil contains mostly chemical bonds of alkyl, followed by carbonyl constituting ketones and carboxylic acids and vinyl. H-NMR analysis of bio-oil and FTIR analysis of wax indicate that the catalyst is more effective in PP pyrolysis rather than CPO deoxygenation reactions to hydrocarbons with unreacted products of the deoxygenation forming wax via ketonic decarboxylation. Steric hindrance by the use of microporous catalyst may cause such incomplete deoxygenation reactions.