Catalytic kinetics for ultra-deep hydrodesulfurization of diesel

A set of rate laws for hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and aromatic hydrosaturation (AHS) of diesel was established to describe ultra-deep HDS in the sulfur concentration range from more than 10,000 ppm to below 10 ppm. High throughput experiments in micro-packed bed reactors with 2 mm inner diameter were conducted using NiMo/Al2O3 catalyst at temperatures from 300 degrees C to 360 degrees C, a pressure range of 4.4 MPa to 7.4 MPa, and liquid hourly space velocity (LHSV) between 0.75 h(-1) and 12 h(-1). To establish the rate laws, the sulfur content was divided into two regions, and the inhibition effects of H2S, nitrogen compounds, aromatics and the virtually refractory compounds were included. All kinetic parameters were estimated by combining genetic algorithm and least square regression to fit experimental data well. Finally, an appropriate operation interval of such reactor was obtained by using the developed model. (C) 2019 Elsevier Ltd. All rights reserved.