Three-Phase Simulation of Hydrotreating of Vacuum Gas Oil

Abstract We develop a numerical model for practical simulation of hydrotreatment of vacuum gas oil in a trickle-bed reactor. The model is based on the mass balance of species; it incorporates a seven-lump chemical scheme that describes the reactions of hydrodesulphurisation and hydrodearomatisation. The novelty of the model is splitting of sulphur-containing compounds into different lumps by their reactive abilities. The splitting is supported by the chromatographic analysis of hydrocarbon mixtures that are sampled from the inlet and outlet ends of an industrial hydrotreatment unit. The analysis reveals different susceptibilities of sulphides, benzothiophene, and dibenzothiophenes to hydrotreatment. The new model is applied for simulation of the hydrotreatment at a refinery, adjusting kinetic parameters, and demonstrating that the model provides an adequate (and, at the same time, simple) description of the process, giving guidance for optimisation that is needed after each variation of the feedstock.