Catalytic Steam Reforming of Toluene as Model Tar Compound of Biomass Gasification over Cu/Ni/Olivine

Abstract

Bimetallic Cu/Ni/olivine catalysts with various Cu/Ni mass ratios were prepared for steam reforming of toluene as model tar compound. The effects of the Cu/Ni ratio, the reaction temperature, and the steam-to-carbon ratio (S/C) on the steam reforming of toluene were investigated in a fixed-bed reactor. Among the catalysts, olivine coated with 3 wt % CuO and 12 wt % NiO (Cu3/Ni12/O) achieved higher catalytic performance and structural stability due to the synergistic effect of Ni and Cu. The appropriate S/C and a higher temperature were beneficial to steam reforming of toluene. The catalytic performance was not only affected by the amount but also by the types of carbon deposition. Compared with the amorphous carbon, the larger amount of graphitic carbon formed on the catalyst surface was more likely to lead to a decreased catalytic performance.

A review of the thermochemistries of biomass gasification and utilisation of gas products

“…Indeed, secondary catalysts promote the conversion of products of incomplete gasication of the original biomass to enhance the yields of hydrogen and CO. Such post-biomass gasication reactions include downstream steam reforming of methane (and other hydrocarbons) in the gas products (eqn (10)), [116][117][118][119][120] dry reforming methane (and other hydrocarbons) in the gas products (eqn ( 11)) and watergas shi (eqn ( 8)). [122][123][124] Tar formation remains a signicant challenge to the biomass gasication process and requires continued research attention.…”

“…8. 119 In addition, thermal or chemical catalyst deactivation is directly influenced by the nature of the catalyst, reaction parameters and conditions, and biomass characteristics. Often, a noticeable decrease in the hydrogen yield is mainly the initial sign of catalyst deactivation.…”

“…The selection of regeneration temperature is crucial due to the impact of high temperatures on the catalyst form and morphology (sintering). 119 As a result, it must be noted that regeneration affects the catalyst lifetime, and therefore, stable catalysts after repeated regeneration cycles are more desired. As a result, regeneration methods based on lower or at least balanced temperatures with high efficiencies are more desired.…”