Catalytic upgrading of NaoMaohu and biomass co-pyrolysis over HZSM-5/CuMgAl

Abstract

A mechanistic study of catalytic pyrolysis is essential for the high-value utilization of coal. This work is to investigate the catalytic upgrading of NaoMaohu coal (NMH) pyrolysis volatiles by analyzing the yields and compositions of pyrolysis products. The experimental results showed that the addition of biomass effectively reduced the char yield (7.4 wt%) and increased the yield of the volatile fraction. To optimize product distribution, the acidic center of HZSM-5 promoted the aromatization of tar, resulting in an aromatic content of 68.12 wt%. Additionally, CuMgAl increased the CO₂ yield by 8.88 wt%. In this context, the tandem catalysis (HZSM-5/CuMgAl) optimized the product distribution through a synergistic effect, increasing the tar aromatization content to 76.88 wt%, while reducing the char and water yields by 7.5 wt% and 3.9 wt%, respectively. Tandem catalysis involved CuMgAl cleaving macromolecules into intermediates, which diffused into the pores of HZSM-5 for cyclization and condensation. The findings underscore the viability of acid–base tandem catalysts for converting low-rank coal and biomass into high-value aromatics.