Yousef Tamsilian - Sharif University of Technology, Chemical and Petroleum Engineering Department, Tehran, Iran
Ali Nejad Ebrahimi - Sharif University of Technology, Chemical and Petroleum Engineering Department, Tehran, Iran.
Reza Azadi
Ahmad Ramazani S.A

There are several common methods to produce the styrene monomer in the industrial units, including the ethylbenzene (EB) adiabatic dehydrogenation, the ethylbenzene isothermal dehydrogenation, simultaneously styrene producing and propylene oxidation, membranous process for the ethylbenzene dehydrogenation, and the ethylbenzene dehydrogenation and oxidation using carbon dioxide. Styrene production unit in Iranian Petrochemical Complex has used the ethylbenzene (EB) adiabatic dehydrogenation process to prepare the styrene monomer where undesirably styrene polymer is formed by applied process conditions. According to solve this problem, there are two solutions: 1) changing difference applied process conditions; 2) using polymerization inhibitors. In this study, the production process is modified by investigation of polymerization conditions, and operation conditions are optimized using mathematical kinetic models in accordance with Hougen-Watson method (as non-porous Model). Besides, all kinds of the polymerization inhibitors are investigated to select the best ones for the employed operation conditions. The obtained results depict that residence time in the heat exchangers and separation vessel should be reduced, and organic-aqueous separator should be modified by other stabilization approaches instead of using mesh grid method. Furthermore, the operation conditions such as selectivity, feed temperature, and flowrate ratio profiles for the main components based on a new presented catalyst are optimized to diminish the possibility of polymerization formation.

Styrene monomer, ethylbenzene dehydrogenation, Hugen-Watson porous model, process conditions, polymerization inhibitors