Influence of interaction between biomass inorganic components and volatiles on corncob pyrolysis and char structure

Abstract

A thorough understanding of the mechanism of interaction between biomass inorganic components (BICs) and volatiles is critical for the pretreatment and subsequent utilization of pyrolysis products. As a result, the low- and medium-temperature pyrolysis features of corncob before and after deashing with hydrochloric acid were investigated via the analysis of product distribution, bio-oil, and bio-gas composition, organic functional groups, and char's two-dimensional correlation infrared spectrum. BICs accelerated secondary pyrolysis of corncob and improved molecular structure rearrangement of char. CO2 production was reduced by 29% on average due to deashing, while levoglucosan (LG) yield was raised with a maximum relative content of 29.1%. At low temperatures (< 350°C), BICs enhanced depolymerization of biomass polymer and promoted glycosidic bond breaking, dehydration, and ring-opening reactions, resulting in a reduction in CO and COC structures in char. At medium temperatures (350– 600°C), BICs promoted the dehydroxymethylation and cyclization of linear structures to generate cyclopentanone and benzenes, increasing the generation of CC, CH, and aromatic structures in the char. The results contribute to a better understanding of the interaction mechanism between BICs and pyrolysis volatiles.