A novel multistage vapor recompression reactive distillation system with intermediate reboilers

Abstract

in Wiley Online Library (wileyonlinelibrary.com).Most of the published studies have focused on the thermal integration of nonreactive distillation columns. The key limitation of reactive distillation (RD) technology is that the necessary conditions (such as pressure and temperature) for the reaction must match those of distillation. Owing to this constraint, the reaction conversion may be adversely affected at the elevated pressure in the reactive section of an internally heat integrated distillation column (HIDiC). This fact forces us to adopt an external heat integration approach for an industrial heterogeneously catalyzed ethyl tert-butyl ether (ETBE) RD column. The direct vapor recompression column (VRC) is an external heat integration scheme that is successfully used as an energy efficient scheme for separating a close-boiling mixture. Interestingly, there exists a large temperature difference between the two ends of the representative ETBE column, and it makes the external heat integration more challenging. Aiming to improve the thermal efficiency of the ETBE column under the VRC framework, various heat pump arrangements with intermediate reboiler(s) (IR(s)) are explored and analyzed with performing a comparative study in terms of energy consumption and economics. To improve further the thermal efficiency, in this contribution, a novel multistage vapor recompression RD column with IRs is introduced addressing a number of practical concerns. An algorithm for the proposed column is formulated showing the sequential steps involved in heat integration. It is inspected that the proposed multistage vapor recompression RD system appears overwhelmingly superior to the classical vapor recompression RD and its conventional stand alone column providing a significant savings in energy as well as cost.

Heat pump assisted reactive and azeotropic distillations in dividing wall columns

“…1(c). Jana [6] and Kumar [7] introduced the modified MVRHP scheme for reactive multicomponent distillation columns, which show better economic feasibility than the conventional heat pump assisted reactive distillation columns.…”

Introducing vapor recompression mechanism in heat‐integrated distillation column: Impact of internal energy driven intermediate and bottom reboiler

“…Supplying heat at the highest temperature point (i.e., column bottom) of the VRC scheme is not thermodynamically favorable, particularly when the boiling point temperatures of the components to be separated are far apart. In this regard, some developments are made and it is recommended to install the intermediate reboiler (IR)/heat exchanger (HE) in a VRC structure that mainly targets to distribute the heat along the column length, thereby reducing the compressor work.…”

“…In a previous study, we have introduced a mechanism detailing the optimal use of IR(s) in the VRC. A number of variants of the VRC system coupled with IR is developed there.…”

Evaluation of a novel configuration of bottom flashing on dual distillation columns for saving energy

“…Various configurations of these systems have been presented in previous studies [7,8,18,[20][21][22][23][24][25]. These configurations include: vapor recompression with intermediate reboiler(s) [20,26,27], vapor recompression with self-heat recuperation [28], vapor recompression with extra heat transfer units [7], vapor recompression and bottom flashing on petlyuk column [8], simplified heat integrated distillation column [25], heat integrated distillation with additional heat transfer between top product and feed [12] and heat integrated distillation columns for separating ternary mixtures [14].…”

“…These configurations include: vapor recompression with intermediate reboiler(s) [20,26,27], vapor recompression with self-heat recuperation [28], vapor recompression with extra heat transfer units [7], vapor recompression and bottom flashing on petlyuk column [8], simplified heat integrated distillation column [25], heat integrated distillation with additional heat transfer between top product and feed [12] and heat integrated distillation columns for separating ternary mixtures [14]. Current trends of using process intensification principles, along various optimization techniques for simultaneous control and design for improving performance of distillation systems were studied in a recent paper [29].…”