Simulating Study On Flow Field Distribution In Residual Oil Hydrogenation Ebullated Bed Reactor

With the continuous consumption of energy in the world,petroleum resources,as the most important non-renewable energy and the most important source of chemical raw materials,play a very important role in the strategic material reserves of various countries.Ebullated bed reactor is a new type of heterogeneous catalytic reactor.In the past 60 years,the reactor has been mainly used to process inferior residue which is difficult to be treated by traditional technology.With the rapid rise of China’s economy,the demand for energy consumption is also increasing.Therefore,it is urgent to accelerate the processing technology of heavy oil in China.The ebullated bed reactor is a heterogeneous catalytic reactor used in the processing of inferior heavy oil.The analysis and study of its internal flow field distribution have important theoretical guiding significance for the optimal design and industrial operation of the reactor.At present,the research of ebullated bed reactor mainly focuses on the catalyst and the control of operation conditions,and there are few reports on its internal flow.There is insufficient theoretical guidance for reactor structure design,optimal operation,performance prediction and device enlargement.The Euler-Naumann model is used to control the gas-liquid and gas-solid interaction force,and the continuous sectional drag model is used to control the liquid-solid interaction forces.The STRONG ebullated bed calculation model is established.The flow field in the ebullated bed reactor is studied.Finally,the reactor is operated under different catalyst loading,residue viscosity and feed inlet velocity.The distribution law of internal flow field is analyzed.The results show that:(1)The three-phase distribution in the reactor is relatively uniform,and the gas phase holdup is higher than the liquid phase and solid phase holdup,which is conducive to the hydrogenation catalytic reaction.The three-phase separator has high separationefficiency and can realize gas-liquid-solid separation.However,the area between the outer ring of the separator and the reactor wall is far away from the mainstream area,which is not conducive to gas-liquid-solid three-phase separation.(2)With the increase of catalyst loading,the total average gas holdup in the reactor decreases.At the same time,in the system with high solid holdup,the bubble coalescence becomes difficult,so the bubble diameter decreases with the increase of solid holdup.When the catalyst loading exceeds 30%,the gas holdup decreases slowly.(3)With the increase of residue viscosity in the reactor,the total average gas holdup in the reactor decreases,and it is easy to form eddies locally.(4)Apparent gas velocity is the most important factor affecting the average gas holdup in the reactor.However,with the increase of gas velocity,the effect on gas holdup becomes gentle.The influence of liquid velocity on gas holdup is relatively small.