Mathematical Modeling of Liquid-Phase Alkylation of Benzene with Ethylene Considering the Process Unsteadiness

Abstract

Ethylbenzene is a key intermediate in the manufacture of styrene that is an important industrial monomer. Ethylbenzene is produced by benzene alkylation using either gas-phase or liquid-phase methods. The liquid-phase alkylation that uses liquid acidic catalysts needs to be improved. We develop a mathematical model for the liquid-phase benzene alkylation. The reaction scheme, designed with a due analysis of desired and side reactions, and with the analysis of the formation of deactivating agents, reflects, in particular, the influence of the concentration of heavy hydrocarbons on the catalyst activity. The account of the catalyst deactivation by heavy alkylaromatics allows predictions of the temporal changes in the outputs of the alkylation process. In particular, the decrease of the ethylbenzene concentration by 2−3 wt % and increase of the polyalkylate outlet concentration by 1.5−2 wt % are the results of the catalyst deactivation. These effects, however, can be compensated by 1.3-time increase of polyalkylate supply and by the temperature increase up to 398 K. The calculations also show that it is possible to decrease the supply of fresh catalyst from 0.498 to 0.472 t/hour without loss in the yield of ethylbenzene.

Mathematical Modeling and Robust Multi-Objective Optimization of the Two-Dimensional Benzene Alkylation Reactor with Dry Gas

“…Hamid et al [10] developed a one-dimensional alkylation and transalkylation reactor model for the factory, which provided a basis for subsequent optimization. Ivashkina et al [11] established a mathematical model for the liquid-phase benzene alkylation batch reactor to study the influence of heavy hydrocarbon concentration on catalyst activity. Additionally, through optimization, the impact of catalyst deactivation can be offset by adjusting operating conditions.…”

Nonsteady-state mathematical modelling of H2SO4-catalysed alkylation of isobutane with alkenes

“…Models of benzene alkylation with ethylene [31,32] and benzene alkylation with higher alkenes [33,34] have been developed. These models consider the processes of instability and catalyst deactivation by heavy aromatic compounds.…”