Catalytic aromatization of ethylene in syngas from biomass to enhance economic sustainability of gas production

Abstract

Ethylene aromatization is a novel approach that utilizes gas produced from biomass or waste gasification to facilitate the removal of unsaturated hydrocarbons (precursors of coke in downstream synthesis catalysts) while simultaneously producing a valuable aromatic fraction. The recovery of valuable compounds (ethylene and benzene, toluene, and xylene (BTX)) from biomass-derived syngas effectively improves the economic benefits of the gasification process.This study determined the effects of reaction temperature and Ga loading on the conversion and selectivity of bifunctional Ga–zeolite catalysts for the conversion of ethylene to aromatic compounds. The activity and stability of the synthesized materials were analyzed under realistic gasification conditions by using the gas produced from an indirect gasification process. The maximum ethylene conversion (∼97%) was achieved when 0.025 g/g Ga–zeolite catalyst was used. However, 0.005 g/g Ga–zeolite catalyst exhibited the highest carbon selectivity to benzene (∼32%) and the highest total carbon selectivity to aromatics (73%). The temperature markedly influences the distribution of carbon selectivity to aromatics. Lower temperatures favor the production of ethylbenzene and xylenes, whereas benzene, naphthalene, and naphthalene derivatives are yielded at higher temperatures. The results suggest that benzene formation and toluene formation require different active sites. This study proposes a biomass gasification process to obtain methane for use in industrial applications. Substitute natural gas production ensures economic sustainability by generating in situ high-value-added by-products (aromatics).