Dynamic characteristics of pressure-swing distillation for ethanol-chloroform separation

The steady-state simulation of the pressure-swing distillation (PSD) for separating an azeotrope of ethanol-chloroform was studied based on the pressure-sensitive of the mixture. The process was optimized by minimizing the total annual cost(TAC) using Aspen Plus. The obtained purity of the products was more than 99. 9%. The economy of different heat-integrated processes was investigated on the basis of steady-state simulation. The dynamic characteristics of different heat-integrated PSD for separating ethanol-chloroform binary azeotropic system were studied by Aspen Dynamics. Robust control strategies were built based on the characteristic of different heat-integrated PSD process. The results showed that the economy of the fully heat-integrated process was better than no and partially heat-integrated process and composition-temperature cascade control structure was suitable for no and partially heat-integrated PSD while pressure-compensated temperature control structure was useful for fully heat-integrated PSD. Although fully heat-integrated PSD has the optimal economic efficiency, partially heat-integrated PSD can achieve more robust control than fully heat-integrated PSD. The studies provide certain reference value for the separation of the lower alcohol binary azeotrope with heat-integrated PSD in industrial application. © 2016, Chemical Industry Press. All right reserved.