Numerical Simulation Of Bubble Column Reactor And Distributor For Slurry Bed Hydrocracking

Heavy oil slurry bed hydrocracking technology is the ideal process to make the heavy oil light,and it is strategically important and extremely challenging in petroleum refining industry.The classical reactor used in slurry bed hydrocracking technology is bubble column reactor.The hydrodynamic characteristics of reactor and the design,optimization of distributor is vital in engineering scale-up of reactor.In this paper,the thought and method for designing pipe distributor are summarized,then distributor and reactor coupled with distributor are simulated by using CFD method,which provide the basis for selection of distributor for slurry bed hydrocracking technology,furthermore,provide the assistance for the industrialization of slurry bed hydrocracking reactor.The main research contents are as follows:According to the hydrodynamic experiment of bubble column reactor by Washington University,the computational model of multiphase flow in reactor is established using CFD software.The CFD simulation results are in good agreement with the experimental data,so the model is proved to be reliable and accurate.The thought and method for designing pipe distributor are summarized,and ten ring and spider distributors with different dimension are designed for 50 kt/a heavy oil slurry bed hydrocracking process.Single-nozzle,Venturi-nozzle and multi-nozzle are also designed according to engineering experience.The single phase computational model for pipe distributor is established using CFD simulation method.The distribution laws of hole velocity in ring and spider sparger are analyzed.The effects of hole diameter,hole pitch and pipe diameter on the hole velocity extent of non-uniformity(ENU)are discussed,and optimal pipe distributor dimension is determined.Slurry bed hydrocracking bubble column reactors coupled with designed nozzle distributor and optimal pipe distributor are simulated using verified computational model.The flow characteristics in reactor are analyzed,and the performances of different distributor are compared.The results indicate that pipe distributor is obviously better than nozzle distributor.