Reactor Rearrangement of an Industrial Ethylbenzene Production Unit

In this paper, an industrial ethylbenzene production unit and two new reactor arrangements have been simulated and the results were compared. In most petrochemical plants, ethylene as ethylbenzene production feed is produced at steam thermal cracking units. Almost ethylene is produced excess in these plants because of changing feed rate, feed type and or shut down of any other user unit of ethylene. So finding a new application for consuming excess ethylene in these plants without designing new units is important. In this study, two new reactor arrangements have been proposed. In the first scenario, the 3rd bed of transalkylator plays alkylator role instead of transalkylator and in the second scenario, all three beds were used as a parallel reactor with current alkylator reactors. The results show that ethylbenzene productivity rises 22% and 20% in scenarios 1 and 2, respectively, compared to a commercial industrial unit. Finally, one of the effective parameters in ethylbenzene unit is the ratio of ethylene to benzene in the feed of all beds of reactors, so it was selected as decision variable and ethylbenzene productivity as the objective function of an optimization problem. All cases were optimized and results show 43% ethylbenzene productivity improvement in an optimized version of scenario2 in compared other scenarios.