Simulation For Alkylation Of Benzene With Propylene And Ethylene By Reactive Distillation

Reactive distillation technology which enforces the reaction and separation is a special distillation form developed quickly in recent years. Compared to the traditional process, reactive distillation method has many advantages and has the satisfactory of the green and economy. Therefore, it has proved to be an important research field in chemical separation.Alkylation reaction of benzene has been used widely in industry. The production methods of alkyl benzene comprise gas phase, liquid phase and catalytic distillation method. Moreover, catalytic distillation method used in producing ethylbenzene and cumene by dry gas could save energy and reduce pollution. Consequently, it has a good application prospect.The simulation of reactive distillation process of benzene with ethylene and propylene has been taken place, and the main works are as follows:Firstly, the equilibrium (EQ) stage model was used to describing the distillation processes which contain the ethylene and propylene with benzene respectively, and computer simulation was conducted with the FORTRAN program. Then the experimental result was provided to compare the simulation of both EQ stage model and non-equilibrium (NEQ) stage model. It can be observed that two models could agree well with the experiment and there have no considerable difference between them for this system. Therefore, the EQ stage model is able to describe the alkylation of benzene with ethylene and propylene.Secondly, Qualitative analysis of the above alkylation reaction distillation process to operating parameters and the major variables were conducted. It mainly contained the feed B/E (P) molar ratio, column operating pressure, stage numbers of reactive section, reflux ratio, weight space velocity of benzene, feed E (P) position and packing fraction of catalyst. The conversion of the product and TAC (total annual capacity) were used for indicator to the optimization operation.Thirdly, as a result of the mixture of ethylene and propylene in refinery dry gas, the distillation process which include the reactive distillation with the feeding of benzene with ethylene and propylene and the conventional distillation of the bottom. According to analysis of parameters, orthogonal experiment design was designed and the optimal designing scheme which is measured by olefins conversion and TAC was determined. It turned out that the olefins conversion and TAC can meet requirement, as well as separation target. Fourthly, since the complexity of the reaction rate model makes the simulation of dynamic process of reaction distillation difficulty. What is more, the industrial process of benzene and olefins reaction distillation process is go through the reactor firstly, and then conduct distillation separation. Therefore, the dynamic simulation of the bottom is carried through, and then step response process in feeding flow rate and composition of 10% of the disturbance was investigated. The results show that another steady-state value can reach after a series of changes and it can be accord with requirement of smooth operation.