A hybrid heat integration scheme for bioethanol separation through pressure-swing distillation route

In this contribution, a hybrid thermal integration scheme is proposed for a pressure-swing distillation (PSD) column by combining an internally heat integrated distillation column (HIDiC) with vapor recompression column (VRC). The purpose of this article is three fold: first, it designs a HIDiC for a PSD system with a reduced number of internal heat exchangers. Second, it develops a hybrid column configuration by integrating that HIDiC, which is devised based on the thermal driving force existed between the two diabatic columns, and VRC that is devised based on the thermal driving force existed between the top and bottom of the same high pressure column, yielding an ideal HIDiC-VRC configuration. Third, it provides a comprehensive comparison between the HIDiC-alone and its hybrid HIDiC-VRC structure with reference to a conventional standalone PSD column. To evaluate the performance of all these configurations, we estimate the two performance indexes, namely energy consumption and total annual cost, for an example of a bioethanol dehydration system. (C) 2015 Elsevier B.V. All rights reserved.