2018 Volume 51 Issue 10 Pages 890-897
This study set out to examine the use of heat integration to minimize the energy consumption of a hybrid membrane separation (vapor permeation)–distillation hybrid process for the dehydration of isopropyl alcohol (IPA). The retentate stream from the membrane was used as a heat source. Energy consumption of the hybrid process was evaluated by a model-based simulation, which was developed using Pro/II and an Excel VBA program. In the development of the simulation model, the stage-cut and reboiler duty were used as the parameters of the hybrid process. Energy consumption of the hybrid membrane separation–distillation process, which involves heat integration with the retentate stream and the reboiler, became smaller than that of a hybrid membrane separation–distillation process without any heat integration. To increase the degree of heat exchange by increasing the temperature differential, we evaluated the heat integration combinations of retentate stream and the stages in the distillation column. The distillation column consisted of nine stages, including the reboiler. Within the scope of the present study, it was found that heat integration with the fifth stage of the distillation column minimized the reboiler duty. The reboiler duty of the hybrid membrane separation–distillation process, with heat integration with the fifth stage, was 11% less than that of a hybrid membrane separation–distillation process with heat integration with the reboiler, and 48% less than that of a process without any heat integration.