The effective diffusivity of hydrogen in an industrial catalyst CuO/ZnO/γ-Al2O3 pellet was measured with a modified Wicke-Kallenbath steady-state diffusion cell at 373 to 413 K and 0.4 to 1.0 MPa. Through changing the flow rate of cyclohexane in a sequence from low to high to a maximum and then vice versa

the effect of relative vapor pressure of cyclohexane on the effective diffusivity of hydrogen was investigated in the presence of capillary condensation within the catalyst pores. Condensation started at the relative vapor pressure of cyclohexane of 0.42 at 373 K

while it was delayed to the relative vapor pressure of 0.6 at 413 K. Besides

shrinking of hysteresis loops was observed with the increase of temperature

and the effective diffusivity of hydrogen also displayed multiple hysteresis loops with respect to the relative vapor pressure of cyclohexane. A correlation between the effective diffusivity of hydrogen and catalyst internal wetting fraction was proposed

and it showed good agreement between calculation and experimental data.