Numerical Simulation And Structure Optimization Of Distributor For Fixed-bed Hydrogenation Reactor

The crude oil is becoming heavier and inferior in quality,in addition,the environmental regulations are becoming stricter.Efficient processing of heavy oil has become an opportunity and challenge for the world's oil refining industry.In the global heavy oil hydrogenation unit,the fixed bed hydrogenation accounts for about 80%.The development and optimization of the internals in the fixed bed reactor have always been the key point and difficulty in optimizing the hydrogenation process.In the fixed bed reactor,the distributor is one of the most important components.This paper is based on the Cold model experiment of distributor in literature.Computational fluid dynamics(CFD)is used as a research tool for numerical simulation.The simulation results were in good agreement with the experimental results to verify the accuracy of the Euler-Euler double-phase flow model and standard k-? turbulence model.In this paper,three different principles of distributor,overflow,overflow-broken and spray type were studied.For each type of distributor,firstly,the basic structure was simulated and obtained its basic performance parameters.Secondly,the structural optimization of each distributor is carried out mainly through parameters such as distribution unevenness,spraying area and pressure drop to investigate the performance of the modified distributor.The simulation results show that overall performance of modified distributor compared with the basic configuration is better.Compared with the basic configuration,the distribution unevenness of the BL distributor was decreased by 51.53%,the spraying area was increased by 176.67% and the pressure drop was increased by 75.38%;The distribution unevenness of the spray distributor was decreased by 78.76% compared with the basic configuration,the spray area was increased by 293.3% and the pressure drop was increased by 23%;The distribution unevenness of the HD overflow distributor was decreased by 8.27% compared with the basic configuration,the spraying area kept unchanged,the peak value of liquid phase was decreased by 24.23% and the pressure drop was decreased by 65.52%.