Catalytic pyrolysis of cashew de-oiled shell and spent lemongrass

Abstract

Residual/ spent biomasses are rising each day due to the increased processing of crops to extract essential oils. An efficient method is required for its management and value-addition. Therefore, this study aims to explore the catalytic pyrolysis of two residual biomasses, i.e., cashew de-oiled shell and spent lemongrass biomass. Different metal oxide(s) catalysts prepared using Al2O3 support, i.e., Fe2O3/Al2O3, Co3O4/Al2O3, Mn2O3/Al2O3, and NiO/Al2O3, are considered for this study. From the product distribution, it was analysed that the incorporation of catalyst led to a decrease in the bio-oil yield as compared to non-catalytic pyrolysis, which showed that Al2O3-supported catalysts promote the cracking reactions of pyrolysis vapours and produce lighter molecules. It was found that the incorporation of catalysts significantly affected the content of the functionalities present in the pyrolysis bio-oil. Fe2O3/Al2O3 was observed to greatly increase the area % of phenolics up to 52.35 and 75.57 area % in spent lemongrass and cashew de-oiled shell bio-oil, respectively. Metal oxide catalysts were also observed to reduce the oxygenates and produce high-quality bio-oil. Overall, this study demonstrates the effective utilization of cashew de-oiled shell and lemongrass biomass for cleaner energy/chemicals production through catalytic pyrolysis, highlighting the potential of metal oxide supported on Al2O3 catalysts in biomass valorization.