The impact of various catalysts on pyrolysis bio-oil characteristics and catalyst coking behavior of corn stover

Abstract

ABSTRACT Biomass has immense potential to address energy and environmental issues. Catalytic pyrolysis is an effective technology for utilizing biomass. Six catalysts (CaO, Al2O3, Fe2O3, MCM-41, HZSM-5, and red mud(RM)) were used to pyrolyze corn stover in a fixed-bed reactor. Six catalysts (CaO, Al2O3, Fe2O3, MCM-41, HZSM-5, and red mud (RM)) were used in a fixed-bed reactor. The feedstock-to-catalyst (FCR) ratio was adjusted to optimize the catalytic effect. The comprehensive evaluation of the catalysts was carried out by analyzing the deoxygenation effect, liquid yield, and catalyst coke accumulation behavior through TG, GC-MS, SEM/EDS, and XRD techniques. The study revealed that superior deoxygenation performance among the six investigated were HZSM-5, CaO, and RM. At the highest FCR (2:1), the liquid yield and deoxygenation effect of CaO are both at their optimal state simultaneously. The bio-oil yield reached 51.98%, but it has a coke accumulation of 27.07% by TG. MCM-41 and HZSM-5 exhibited more severe coking with coke contents of 8.14% and 8.04%, respectively, along with higher maximum heat loss temperature, upon dichloromethane extraction. The relative peak areas of alkanes in the coke accumulation were more than 50% except for RM, which the main component of the latter was polycyclic aromatic hydrocarbons (78.43%). By comparing the bio-oil characteristics and carbon accumulation behavior of different catalysts, it provides a reference for the study of carbon accumulation in pyrolysis catalysts.