Catalytic Pyrolysis of Biomass to Produce Aromatic Hydrocarbons over Calcined Dolomite and ZSM-5

In this study, the method for the promotion of aromatics production through catalytic pyrolysis of biomass over the combination of calcined dolomite and ZSM-5 was investigated. The influence of reaction conditions and catalyst type on product distribution was studied in pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and a fixed-bed reactor. The results showed that calcined dolomite favored the removal of acids, sugars, and methoxyphenols, reducing the content of oxygen-containing components with a lower effective hydrogen to carbon ratio and larger molecule size, which thus enhanced the formation of BTX (benzene, toluene, and xylene) over ZSM-5. The highest BTX yield was achieved when the mass ratio of biomass:calcined dolomite:ZSM-5 was 1:1:4, which was 22.92% higher than ZSM-5 alone and 8% higher than the conventional CaO/ZSM-5 system. On the other hand, calcined dolomite favored the formation of H-2, contributing to the inhibition of the formation of naphthalene and 2-methyl-naphthalene.