Hydrothermal gasification of poplar wood chips with alkali, mineral, and metal impregnated activated carbon catalysts

In this study, poplar wood chips were gasified in sub-and supercritical water as biomass feedstock. Hydrothermal gasification experiments were performed to examine how the reaction temperature and different type of catalysts influence conversion efficiency. The effectiveness of commercially available [alkali catalyst; KOH], naturally available [mineral catalysts; Trona [Na-3(CO3)(HCO3)center dot 2H(2)O], Dolomite [CaMg(CO3)(2)] and Borax [Na2B4O7 center dot 10H(2)O] and laboratory-prepared catalysts [metal-impregnated activated carbons; (Ni/AC) and (Ru/AC)] have been demonstrated so as to shift the product distribution toward more desirable compounds. Gaseous compound yield was increased from 29.7% to 79.3% with respect to increasing temperature while liquid compound yield decreased from 27.6% to 1.1% and solid residue from 38.0% to 15.6%. The highest H-2 (20.1 mol/kg C in poplar) and CH4 (12.7 mol/kg C in poplar) yields were obtained with Ru/AC catalyst. Carboxylic acids and 5-methyl furfural were determined as the main liquid compounds. (C) 2019 Elsevier B.V. All rights reserved.