Optimization and heat integration of hybrid R–HIDiC–PV process with the series–parallel arrangement of PV modules and recycle streams for TAME production

Abstract

Tert–amyl methyl ether (TAME) production process is consisted of a reactor, a reactive distillation (RD) column and the methanol recovery section. The bottom product of the RD column is TAME while the distillate is consisted of the azeotropic mixture of methanol and isopentane (i-pentane) that can be separated by either the pervaporation (PV) membrane or conventional pressure swing distillation (PSD) and extractive distillation (ED) methods. The PV process allows the use of both series and parallel arrangements. The series arrangement has a lower membrane area compared to the parallel arrangement, while the parallel arrangement has a lower energy cost. A series–parallel arrangement with recycle streams was used in the present study to take advantage of both the series and parallel arrangements. The HIDiC method was used for reducing energy consumption in the RD column. Moreover, heat integration between PV streams and internal flows in the RD column was used to reduce PV energy consumption. The number of modules in each row, the recycle stream, the heat exchange ratio between the rectifying and stripping sections in the RD column and the heat exchange ratio between PV streams and internal RD streams were obtained by a hybrid GA–PSO algorithm. Furthermore, all RD and PV parameters were considered optimization variables and most importantly, all process variables were optimized simultaneously. According to the results, the proposed process reduced the total annual cost (TAC) by 52% and led to a 57% energetic gain compared to the conventional hybrid RD–PSD process. The proposed process also reduced TAC by 48% and led to a 40% energetic gain in comparison with the hybrid RD–PV process. This can be related to the reduced membrane area compared to the series and parallel arrangements as well as reduced energy costs of PV heaters through heat integration between PV steams and internal flows of the column.