CFD simulation and temperature regulation of the coke drum
Coke drum is the conventional reactor for processing heavy oil into light chemicals in petrochemical industry.Because of the high operation temperature within the reactor,experimental monitoring is particularly difficult.The complex processes within the coke drum involve the fluid flow,heat transfer and reaction,and the heterogeneous temperature distribution make it challenging for precise regulation.This study considers the distribution of gas phase,liquid oil,and solid coke in the reactor and adopts continuous medium model(Eulerian model)to simulate the motion of three phases and couples the heat transfer model and seven-lumped reaction kinetics model,so as to establish a multiscale model for the coke drum reactor.The accuracy of this model is validated by comparing the simulation and experiment results in the kettle reactor.Furthermore,the feeding process and the coke growth from mesoasphaltene are modelled,and the flow field,temperature distribution,and coke generation rate under different operating conditions are studied.The results show that the coking process and the heterogeneous distribution of multi-physical field in the reactor are greatly influenced by temperature.The mass fraction and growth rate of coke and gas products increase a lot at high temperature.In order to regulate the distribution and growth rate of the coke product,the mesoasphaltene,which is the precursor product of the coke,is generated with temperatures no more than 450℃ at feeding stage,so that the coke growth rate is restricted.Afterwards,the temperature is improved by heating reactor walls and injecting high-temperature steam,in which the reaction rate of mesoasphaltene towards coke product increases and the uniform distribution of coke can be obtained.This study provides an important case for regulating distribution and growth of coke product by coordinating the temperature field and flow characteristics within the coke drum.
coke drumEulerian modelmesoasphaltenetemperature regulationcoke distribution