Co-Pyrolysis of torrefied biomass and methane over molybdenum modified bimetallic HZSM-5 catalyst for hydrocarbons production

Abstract

Catalytic pyrolysis of torrefied switchgrass under methane atmosphere was performed over molybdenum modified bimetallic catalysts. Compared with molybdenum-only catalysts (MoO₃/HZSM-5 and Mo₂C/HZSM-5), the bimetallic catalysts demonstrated a higher catalytic performance towards methane activation. Higher reaction temperatures favored formation of aromatic hydrocarbons under both helium and methane atmospheres. The maximum aromatic hydrocarbons yield of 39.31% was achieved during co-pyrolysis of raw switchgrass and methane over MoZn/HZSM-5 at 700 °C. Torrefaction prior to pyrolysis led to a decrease in the aromatic hydrocarbons yield. The yield of aromatic hydrocarbons from switchgrass torrefied at 270 °C was lower than that when torrefication was performed at 230 °C. The reduction of aromatic hydrocarbons from torrefied switchgrass is due to the loss of cellulose and the concomitant concentration of lignin during torrefaction.