Reversible Reaction-Assisted Intensification Process for Separating the Azeotropic Mixture of Ethanediol and 1,2-Butanediol: Vapor–Liquid Equilibrium and Economic Evaluation

Abstract

Vapor−liquid equilibrium data of six binary systems composed of ethylene glycol (EG), 1,2-propylene glycol (1,2-PG), 1,2-butanediol (1,2-BD), and 2,3-butanediol (2,3-BD) were measured and regressed by the NRTL model. With the binary interaction parameters regressed by experimental data, four separation processes for obtaining polymer-grade EG from the synthesis products were simulated, including a conventional distillation route, an azeotropic distillation route, a distillation route coupled with liquid−liquid extraction, and a reaction-assisted distillation route. The total annual costs and profits of the four routes were estimated and compared, which indicates that the annual profit was mainly determined by the yield of EG. The results also demonstrate that the reaction-assisted distillation route was proved to be the best strategy currently among those separation methods.

Thermodynamics Foundation and Separation Process Design for Production of Propionic Acid from Ethanol Carbonylation Catalyzed by Iodide

“…The double-circulating vapor−liquid equilibrium apparatus used to take measurements has been described earlier. 23 Thus, only a schematic is shown in Figure 2.…”

Application of Dimethyl Carbonate Assisted Chemical Looping Technology in the Separation of the Ethylene Glycol and 1,2-Butanediol Mixture and Coproduction of 1,2-Butene Carbonate

“…32−35 However, major difficulties exist in the downstream processing of these alcohols because they have high and close boiling points. 35,36 Particularly, EG and 1,2-BDO have a boiling point difference of only 0.5 °C and form an azeotrope. 36 Conventional distillation, which is based on the boiling point difference is usually ineffective as a large reflux ratio and high theoretical plates are needed in the EG refinery column.…”

“…In the dimethyl oxalate hydrogenation process of the coal-to-EG route, 1,2-BDO is coproduced along with ethylene glycol (EG). − Meanwhile, in the one-pot catalytic conversion of biomass to liquid fuels and chemicals, 1,2-BDO is also a by-product along with EG. − Microbial production of bulk chemicals from renewable resources has attracted great attention in recent decades, and EG, 1,3-propanediol (1,3-PDO), 2,3-BDO, 1,2-BDO, and glycerol are valuable products in the fermentation broths. − However, major difficulties exist in the downstream processing of these alcohols because they have high and close boiling points. , Particularly, EG and 1,2-BDO have a boiling point difference of only 0.5 °C and form an azeotrope . Conventional distillation, which is based on the boiling point difference is usually ineffective as a large reflux ratio and high theoretical plates are needed in the EG refinery column.…”

“…In addition, the yield of EG is limited as it is distilled out along with the removal of 1,2-BDO . Thus, physical methods cannot achieve a clear separation of the 1,2-BDO and EG mixture, increase the yield of the EG product, and obtain the 1,2-BDO product. ,, …”

Reactive Distillation: Stepping Up to the Next Level of Process Intensification

“…Furthermore, the products could undergo a reversible reaction to form the original substance using a RD process to achieve the desired separation of the azeotrope mixtures. [13][14][15][16] In spite of the remarkable developments during the past decades, the potential of RD technology has not been fully tapped yet, and there is still undergoing research to improve it further by various process intensification means: e.g. use of dividing-walls, cyclic operation, internally heat integration, high-gravity fields, or coupling RD with other operations (membrane separations), or use of alternative energy (ultrasounds or microwaves).…”