Catalytic pyrolysis of lignin with metal-modified HZSM-5 as catalysts for monocyclic aromatic hydrocarbons production

This work aimed to investigate the feasibility of using metal-modified (Fe, Co, Ni, Cu, Zn, Ga) HZSM-5 zeolite as catalysts for high-value monocyclic aromatic hydrocarbons production via lignin catalytic pyrolysis in a two-stage fixed bed reactor. The structure-performance relationship of the catalysts was revealed based on the cat-alytic reaction testing results along with the acidity and textural properties obtained via systematic physico-chemical characterization techniques, thus guiding the selection of the best modification metal and the optimal loading amount. As demonstrated, the 1 wt% Co modified HZSM-5 (1%Co-HZ) exhibited relatively slight coverage effect on the active sites, while increased the mesoporous surface area and average pore size of the parent HZSM-5 zeolite. Consequently, enhanced mass-transfer efficiency was attained by the 1%Co-HZ catalyst, which achieved the highest monocyclic aromatic hydrocarbons content (29.3%) among all the investigated metal-modified HZSM-5 catalysts. In addition, the Co modified sample showed better resistance to carbon deposition than that of the unmodified one. Overall, 1%Co-HZ can be used as an effective catalyst for monocyclic aromatic hydrocarbons production in lignin catalytic pyrolysis.

Automated summary

This study investigated the feasibility of using metal-modified HZSM-5 zeolite as catalysts for monocyclic aromatic hydrocarbons production in lignin catalytic pyrolysis. The 1%Co-HZ catalyst showed excellent performance and resistance to carbon deposition.