engleski

Performance of Ni/Al2O3 Pellets Poisoned by Thiophene

A quantitative assessment of the internal mass transport effect on a catalytic system involving chemical poisoning is based on solving a set of coupled partial differential equations describing reactant and product concentrations and activity profile with the catalyst particle. It is convenient to describe the results by a pellet effectiveness factor for the main reaction which depends upon time, intraparticle position, diffusion and reaction parameters. Based on kinetic of gas phase benzene hydrogenation to cyclohexane, catalyst poisoning and pore diffusion time-dependent effectiveness behaviour of Ni/Al2O3 catalyst pellet were simulated. Deactivation data were collected in an isothermal fixed-bed reactor at hydrogen partial pressure of 99.82 kPa, benzene partial pressure of 7.55 kPa, thiophene partial pressure of 0.032 kPa and at reaction temperatures ranging from 403 to 473 K. The time-dependent effectiveness factor obtained as a function opf Thiele modulus was compared with experimental observation for commercial catalyst pellet. A degree of correlation between theoretical prediction and experimental results was generally satisfactory when benzene hydrogenation was represented by a power-law kinetic equation. By contrast, the fit obtained with the Hougen-Watson kinetic model for benzene hydrogenation is poor due to changes in adsorption constants with extent of poisoning.

Catalyst Deactivation ; Mass Transport Effect ; Kinetic Modelling

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