Simulation and optimization of axial-flow and radial-flow reactors for dehydrogenation of ethylbenzene into styrene based on a heterogeneous kinetic model

• Published in: Chemical engineering science Vol. 244; p. 116805
• Main Authors: Leite, Bruno, Oliveira Souza da Costa, Andréa, Ferreira da Costa Junior, Esly
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 23.11.2021
• Subjects: Dehydrogenation; Heterogeneous kinetics; Multiobjective optimization; Simulation; Styrene; Heterogeneous kinetics; Simulation; Dehydrogenation; Multiobjective optimization; Styrene
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/j.ces.2021.116805

•Low pressures have great impact on styrene conversion (yield) and selectivity.•Optimal inlet temperatures are increasing from the first to the last catalyst bed.•Radial-flow reactors are a better alternative than axial-flow when optimized.•It was obtained simultaneously styrene conversion of 76.5% and selectivity of 87.0%. In this study, steady-state axial-flow and radial-flow multibed catalyst reactors for dehydrogenation of ethylbenzene into styrene were simulated based on an intrinsic heterogeneous kinetic model. The reactors were then optimized using nonlinear programming with the multiobjective function of maximizing styrene selectivity and conversion. The simulations were consistent and versatile. Comparing the two optimized reactor configurations, radial-flow has proved to be a better alternative than axial-flow because of operating at lower pressures. The benefits of operating at lower pressures are also evident at optimized inlet temperature schemes, as the inlet temperatures of catalyst beds are greater along reactor pressure drop. The obtained set of optimal results can be used to perform an integrated process analysis and define suitable operational conditions. Weighing objective functions with respectively 0.3 and 0.7, styrene selectivity and conversion were respectively 85.3% and 72.5% for the axial-flow reactor and 87.0% and 76.5% for the radial-flow reactor.