Enhancement of perovskites performance for coal tar decomposition by pore structure and acid-base modification

Abstract

Catalytic cracking is an efficient way to replace conventional combustion to remove coal tar deposited at the gas outlet of COREX melter gasifier. This work prepared a series of LaNi0.8Fe0.2O3 perovskites (Ni 0.8) with different pore structures via the hard-template method and applied in the catalytic cracking of coal tar was operated at 700 °C to evaluate the performance of perovskites. Ni 0.8 prepared via MCM-48 template (MCM-0.8) exhibited the high specific surface area (SSA) of 90.2 m2/g and pore volume of 0.3 cm3/g, accounting for its highest gas yield (51.8 mmol/gcoal) and complete tar removal. The remarkable oxidation capacity of MCM-0.8 resulted in its highest CO2 yield (11.2 mmol/gcoal) and selectivity for oxygenated compounds in tar (71.1 %). Three mesoporous Ni 0.8 participated in the catalytic reactions as the acid-base bifunctional catalysts. Ni 0.8 prepared via SBA-15 template (SBA-0.8) showed a great hydrocracking activity due to its strongest acidity of 1.87 mmol/g. All the synthesized perovskites possessed a good reactant selectivity, and the tarry product selectivity over different perovskites was influenced by the synergistic effect of acidity and the reactant diffusion inside the catalyst channels.