Intensifying reactive dividing-wall distillation processes via vapor recompression heat pump

Abstract

Recently, reactive dividing-wall distillation (RDWD) has attracted much attention due to its capacity of process intensification. Nevertheless, its energy efficiency and economic benefit are likely to be enhanced by employing vapor recompression heat pump (VRHP) to reuse the energy of its overhead vapor. In this study, we explore the feasibility and effectiveness of this technology in two representative RDWD processes with different operation characteristics through in-depth evaluations of the steady-state performance of the VRHP reinforced RDWD (i.e., the proposed RDWD-VRHP). The first process involves the esterification of mixed acid (acetic acid and propionic acid) with methanol to yield methyl acetate, methyl propionate, and water. The second process involves the reaction of glycerol and hydrochloric acid to produce 1,3-dichlorohydrin, 2,3-dichlorohydrin, and water along with the intermediate products of 1-monochlorohydrin and 2-monochlorohydrin. Different configurations of the RDWD-VRHP are proposed for these two reaction systems and a systematic design procedure is developed to determine the optimum combination of the VRHP and the RDWD. Simulation results demonstrate that the RDWD-VRHP can substantially reduce utility consumption of RDWD. Especially, much more economic benefit can be secured by VRHP for the RDWD column with small column temperature difference and high latent heat in the overhead vapor.