engleski

Thiophene Poisoning of Ni-SiO2-Al2O3 in Benzene Hydrogenation. Deactivation Kinetics

The poisoning kinetics of tiophene on Ni-SiO2-Al2O3 catalysts has been studied experimentally using benzene hydrogenation to cyclohexane as a model reaction. The poisoning kinetics was measured in a series of differential reactor experiments at atmospheric total pressure, a benzene partial pressure of 7.55 kPa, a hydrogen partial pressure ranging from 39.07 to 99.82 kPa, a thiophene partial pressure of 0.32 kPa, and temperatures from 403 to 473 K. Exellent agreement was found with a power law equation for the rate of change of activity with time, with apparent activation energies that increase slightly with hydrogen pressure from -5.07 kJ/mol at 39.07 kPa to -8.07 kJ/mol at 99.82 kPa. Since the strenght of thiophene adsorption on nickel decreases with increasing temperature, the slightly decreasing rate of deactivation with increasing temperature is what might be expected and could be a reason for the apparent activation energy that is negative.

Thiophene poisoning ; Benzene hydrogenation ; Deactivation kinetics

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