Supercritical water gasification of phenol over Ni-Ru bimetallic catalyst: Intermediates and kinetics

Phenol is gasified in supercritical water at 400-500 degrees C under a pressure of 25 MPa over Ni-Ru bimetallic catalyst. Several liquid products including cyclohexanol, 2-methyl cyclopentanone, toluene, alkylphenol etc. are identified and possible reaction paths among them are proposed. Gaseous products consist of H-2, CH4 and CO2. We develop a quantitative kinetic model based on a simplified reaction network in which intermediates are lumped. The model accurately captures the trends of concentration variation for phenol and gaseous products. Steam reforming of phenol to form CO is the main source of H-2 and nearly all CH4 is formed from methanation of CO under 450 degrees C. Concentration of H-2 is most sensitive to steam reforming to form CO2 while steam reforming to form CO strongly affects CH4 production at 450 degrees C. The model has predictive capacity when varying initial phenol loading while it lose some accuracy for a higher water density condition. (C) 2020 Published by Elsevier B.V.