Integrated reaction and separation in a continuous middle vessel column for enhancing indirect hydration of cyclohexene to cyclohexanol

This study introduced economically-viable continuous reactive distillation (RD) design alternatives for cyclohexanol production through the indirect hydration of cyclohexene. The feasibility concept of batch RD was employed for generating the new design alternatives. The first alternative process utilized a continuous stripper for recovering the stable node product of cyclohexyl formate in the esterification reaction and then employed a continuous middle vessel column (MVC) for recovering the stable and unstable node products of cyclohexanol and formic acid in the hydrolysis reaction. The second design had a single MVC-type column having the reactive rectifying zone and the middle vessel reactor for the two respective reactions. The simulation results showed the two alternative sequences required less energy duty than the previously proposed RD process. However, compared to the prior RD process, the life cycle cost (LCC) of the first alternative design increased about 30% due to high equipment costs and the LCC of the second process decreased nearly 40% because of low equipment costs and energy requirements.