Thermal integration of homogeneous azeotropic distillation sequences

Abstract

Existing methods for synthesizing thermally-integrated distillation sequences fail frequently when applied to nonideal and azeotropic systems, because increasing the column pressures often introduces new azeotropes and distillation boundaries into the mixture, which make some separation tasks infeasible. A new thermal integration procedure is presented that combines a bifurcation and residue-curve map analysis with the methods of Andrecovich and Westerberg. The procedure is demonstrated with two commercially important separations: ethanol-water-ethylene glycol and methanol-acetone-water. Energy savings of 65% and 40%, respectively, over the optimized nonintegrated sequences are possible.

Pareto optimization of an industrial ecosystem: sustainability maximization

“…With the purpose of generating a crude estimate of Total Annualized Cost (TAC) of a process, Knapp and Doherty (1990) show that, for a new already-built plant, with expected life of 10 years, 10 annual amortization installments and a yearly attractiveness rate of 12%, ISBL represents approximately 1/3 of the total investment. Consequently, TAC can be written in terms of ISBL according to Equation (2), where OPEX and TAC are expressed in US$/y.…”

Application of Mechanical Vapor Recompression to Acetone – Methanol Separation

“…Non-ideal and azeotropic mixtures are mostly encountered in chemical industries. Many academic research have been conducted to investigate the azeotropic distillation process especially on finding a good approach to decrease the energy consumption to separate the respective mixtures [2], [3].…”

“…Process integration is an attracting choice for handling this issue and it has been successful in decreasing the energy requirements in comparison with sequences where all the units are configured with little or no integration [8]. Knapp and Doherty researched the heat integration of binary homogeneous azeotropic systems using extractive distillation methods [3]. They studied the acetonemethanol mixture with water as the solvent.…”

“…2 illustrates the conventional extractive distillation configuration for acetone -methanol separation. The optimal design of this mixture using the extractive solvent, water, is proposed by Knapp and Doherty [3]. The design used in this work was inspired by their research and also Luyben's work [2].…”

“…The Knapp -Doherty presented the optimal design which has 57-tray extractive column and a 26-tray solvent recovery column, both operating at 1 atm [3]. In order to produce high-purity acetone in distillate the extractive agent is fed to the extractive column on a stage above the feed stage and below the top of the column.…”