Kinetics of the Non-catalytic Water Gas Shift Reaction in Supercritical Water

Abstract

A kinetic analysis of the noncatalytic water gas shift reaction in a supercritical water medium was investigated using a specially designed 383 mL Haynes Alloy 230 tubular reactor at a constant pressure of 24.12 ± 0.04 MPa, water to carbon monoxide molar feed ratios of 5 to 37 moles of water per mole of carbon monoxide, and at temperatures varying from 768 to 1,048 K. The carbon monoxide concentration in the effluent gas reached a minimum of one mole-percent at 1,048 K, which corresponds to a 98% carbon monoxide to carbon dioxide conversion. Using global first-order kinetics a frequency factor of 105.76 ± 1.42 s−1 and an activation energy of 139.8 ± 24.5 kJ/mol was determined. It was also found that the developed kinetic rate model closely fits the experimental reaction data, with a coefficient of determination of R2 = 0.95, over a wide range of temperatures and reactant concentrations.