Ni-modified dolomite for the catalytic deoxygenation of pyrolyzed softwood and non-wood to produce bio-oil

Abstract

This study investigated the effect of process conditions during the catalytic pyrolysis of softwood and non-wood on the pyrolysis product. Ni modified on calcined dolomite (Ni-DM) was used to determine the effectiveness of the catalytic activity and the effect of doping non-noble metals on the product distribution of both pyrolyzed biomasses. The lignocellulosic biomass components showed different effects on the decomposition characteristics of the pyrolysis vapor and its devolatilization, while Ni-DM showed a catalytic effect to enhance the decarbonylation, decarboxylation, and secondary reaction of tar cracking affecting CO2 and CO removal; additionally, the catalytic activity also promoted the formation of aliphatic and olefin hydrocarbon compounds and facilitated C–C cleavage and scission to smaller hydrocarbon compounds. With increased Ni loading, the yield of noncondensable gas increased. Furthermore, gas chromatography analysis indicated that the composition of gas mainly consisted of hydrogen gas, which increased significantly due to a water-gas shift during the catalytic pyrolysis of biomass at high temperature with 10% Ni-dispersed calcined dolomite acting as the catalyst. Meanwhile, the pore structure and the modified-Ni on calcined dolomite enhance decrease acids and sugars in bio-oil yield and favor the formation of alkane gases of liquid hydrocarbon fuels including the dramatically increased in alkane gases.