Kinetic study of high temperature water gas shift reaction

Abstract

The water gas shift reaction has been run at high temperature in a packed bed reactor with a nickel catalyst. The outlet was analyzed by gas chromatography. Gas phase reaction and diffusion limitations appeared to be significant problems for a kinetic study. Rate expressions for different mechanisms have been given in order to find a coherent pathway for the water gas shift reaction over nickel. From the reaction orders of hydrogen and carbon monoxide it was concluded that the redox mechanism was valid at high temperature over nickel with the carbon dioxide formation as the rate determining step. Moreover effect of the diffusion was highlighted by the comparison of the apparent activation energy under chemical and diffusion control. The addition of cobalt in the catalyst showed a better selectivity for the water gas shift reaction.