A Single Particle And Bed Scale Numerical Simulation On Trickle Bed Hydrodesulfurization Performance

The trickle-bed reactor is a gas-liquid-solid three-phase heterogeneouscatalytic reaction, while between phases, within phase and the surface of thecatalyst have very complex physical and chemical processes. Many factors,such as mass transfer and interaction, catalyst shape and effective wetting rate,reactor fluid dynamics, reactor model will affect the reaction performance oftrickle bed. This article select dibenzo-thiophene as the sulfur content of dieselhydrodesulfurization of model compounds, focuses on study the effect ofcatalyst particle shape, particle size, wetting rate on trickle-bed reactor masstransfer and hydrodesulfurization(HDS) reaction, so as to provide a basis forthe research of hydrodesulfurization catalyst and trickle-bed reactortechnology.First, five different particle shapes(sphere, cylinder,3-lobe,4-lobe, anddentiform) of HDS catalyst in the three-dimensional CFD single-particlereaction model were established. Study the concentration, temperaturedistributions of different particles and were compared by using FLUENT. Second, partition the catalyst particles and the above five hydrodesulfurizationcatalysts partial wetting TBR reaction model were established. Study thetransfer characteristics and the HDS reactor characteristics of TBR, and theresults were compared by using MATLAB; Last, the above five HDS catalystsTBR reactor model on different kinetics models were established. Study thetransfer characteristics and the HDS reaction characteristics of TBR, and theresults were compared by using MATLAB; The results show that: TBR of fivedifferent catalysts all have good solid-liquid mass transfer characteristics butbad gas-liquid mass transfer characteristics; The internal diffusion and theHDS reaction characteristics of4-lobe catalyst best. Compared with3-lobecatalyst, dentiform catalyst have the large particle size and the small surfacearea, but its internal diffusion and the HDS reaction characteristics better than3-lobe.That is to say, dentiform catalyst can help reduce the moleculardiffusion path; Compare the five different catalysts bed transfer characteristicsand HDS reaction characteristics, the best performance to the4-lobe, followedby dentiform and3-lobe.