Chinese Journal of Chemical Engineering, Vol.28, No.4, 1095-1106, 2020
Coupling non-isothermal trickle-bed reactor with catalyst pellet models to understand the reaction and diffusion in gas oil hydrodesulfurization
In this work, a trickle-bed reactor coupled with catalyst pellet model is employed to understand the effects of the temperature and catalyst pellet structures on the reaction-diffusion behaviors in gas oil hydrodesulfurization (HDS).The non-isothermal reactor model is determined to be reasonable due to non-negligible temperature variation caused by the reaction heat. The reaction rate along the reactor is mainly dominated by the temperature, and the sulfur concentration gradient in the catalyst pellet decreases gradually along the reactor, leading to the increased internal effectiveness factor. For the fixed catalyst bed volume, there exists a compromise between the catalyst reaction rate and effectiveness factor. Under commonly studied catalyst pellet size of 0.8-3 min and porosity of 0.4-0.8, an optimization of the temperature and catalyst pellet structures is carried out, and the optimized outlet sulfur content decreases to 7.6 wppm better than the commercial level at 0.96 mm of the catalyst pellet size and 0.40 of the catalyst porosity. (C) 2020 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.