Modeling and Optimizing of Cumene Synthesis Using Zeolite-Catalyzed Alkylation

This study focused on simulating and optimizing the production of cumene (isopropylbenzene) through the alkylation of benzene with propylene using a Beta Zeolite catalyst. Two process configurations were evaluated: one without a transalkylation reactor and another incorporating a transalkylation unit to convert byproducts back into cumene. The process was modeled under steady-state conditions in Aspen HYSYS using plug flow reactors and the Peng-Robinson fluid package, with reaction kinetics derived from literature on zeolite-catalyzed systems. Optimization studies examined the effects of reactor temperature, pressure, and benzene-to-propylene molar ratio. Increasing the reactor temperature to 178°C improved propylene conversion to 96.20%, while raising the pressure from 3540 kPa to 3600 kPa further enhanced conversion to 96.24%. The fresh benzene feed flow rate was initially 127.7 kmol/h, which was reduced to 101 kmol/h, and optimizing the benzene-to-propylene molar feed ratio to approximately 0.75:1 increased cumene production to 135.792 kmol/h while minimizing byproduct formation. A comparative analysis revealed that the configuration without a transalkylation reactor produced 4.171 kmol/h of diisopropylbenzene (DIPB) as waste, representing both economic losses and environmental concerns due to its toxicity. In contrast, the transalkylation reactor enabled DIPB conversion into additional cumene, improving process efficiency and sustainability. These findings demonstrate that optimizing reaction conditions including temperature, pressure, and feed ratios along with integrating a transalkylation step, significantly enhances cumene yield while reducing waste generation, leading to a more viable and environmentally friendly process.