Enhancement of bio-oil quality over self-derived bio-char catalyst via microwave catalytic pyrolysis of peanut shell

Abstract

Studies have indicated that a low-cost and high-efficiency treatment process is essential for converting agricultural waste into liquid fuels or chemicals. In the present work, the self-derived bio-char from peanut shell pyrolysis with the loading of selective transition metals (Fe, Co and Zn) were used as a catalyst for the production of more aromatic hydrocarbon contained bio-oil from the microwave pyrolysis of peanut shells. Py-GC/MS analysis results revealed that 10% loaded Fe/Bio-char increased the hydrocarbons in the bio-oil from 3.96% to 38.09%, and selectively, the aromatics hydrocarbon increased from 2.33% to 24.57%. The central combination design (CCD) optimized the microwave pyrolysis temperature and the catalyst to raw material ratio. The response surface area analysis showed that the temperature greatly influences aromatic hydrocarbon production more than the catalyst ratio to the substrate. At the pyrolysis temperature of 550 ℃ and the catalyst/peanut shell of 20%, the bio-oil yield was 24.3%, where the selectivity of hydrocarbon and aromatic hydrocarbon reached the maximum of 26.97% and 17.95%, respectively. The study of self-derived bio-char and the usage as a catalyst in pyrolysis of raw peanut materials under microwave conditions would be a high-value application for catalytic pyrolysis reactions to improve the utilization rate of biomass, reduce the reaction costs, and provide theoretical basis and technical support for the recycling and total utilization of agricultural waste.