Kinetic studies of hydrodesulfurization of thiophene were performed on the commerical Co-Mo, Ni-Mo, Ni-W catalysts under the atmospheric pressure and the temperature of 275℃ to 325℃.
Various rate equations of Langmuir-Hinshelwood type were tested for the selection of the best fit equation using the Powell non-linear least square method.
The following equations were selected for both Co-Mo and Ni-Mo/$Al_2O_3$ catalysts and for the Ni-W/$Al_2O_3$ catalyst, respectively.
$r=\frac{kP_TP_H}{(1+K_TP_T+K_SP_S)^2}$
$r=\frac{kP_TP_H}{(1+K_TP_T+K_SP_S)(1+K_HP_H)}$
These equations suggested the competitive adsorption of thiophene and hydrogen sulfide on the same site with a strong inhibition effect of hydrogen sulfide. Hydrogen was considered to be very weakly adsorbed on the same site or adsorbed different site. And all these results were supported by the hydrogen chemisorption experimental and the TPD experiments of thiophene and hydrogen sulfide.
In addition, an Arrhenius plot of the rate constants of Co-Mo, Ni-Mo, Ni-W/$Al_2O_3$ catalysts gave activation energy of 19.3, 14.7, and 31.6Kcal/mole, respectively.
