Separation of a Close-Boiling 1,2-Propanediol and Ethylene Glycol Mixture Using Pressure-Related Distillation

Abstract

Separation of 1,2-propanediol and ethylene glycol consumes much energy due to their close-boiling points and low relative volatility. By analyzing the influence of pressure on the vapor−liquid equilibrium of the system, it is found that high pressures facilitate the separation. Therefore, a high-pressure distillation process is proposed. For further energy saving, a pressure swing thermally coupled distillation method is used, which divides a distillation column into two columns with different pressures. Therefore, the condenser of the high-pressure column could serve as a reboiler of the low-pressure column. Further energysaving methods via heat integration are proposed. A pressure swing thermally coupled distillation process with heat integration is finally obtained, which ultimately saves all the steam and only adds a little electricity. As a result, a 80.9% reduction of the energy consumption and a 35.5% reduction of the total annual cost are achieved compared with the single-column distillation at 101.3 kPa.

Controllable transformation of biomass-derived diols over an ammonia-modified H-Beta zeolite

“…Based on the fact that the relative volatility between EG and PG is higher at higher pressure, Li et al reported a simulated process to separate EG and PG via pressure-swing distillation. 17 The TAC was reduced by 35% compared with atmospheric distillation. The data of both simulation-based studies can be obviously deviated from practical situations due to the high non-ideality of hydrogen-bond-abundant diol systems, and it should be prudent to evaluate the real performance of dividing-wall-column and pressure-swing distillation techniques.…”

Speleothem-Inspired Copper/Nickel Interfaces for Enhanced Liquid–Vapor Transport by Marangoni and Soret Effects

“…Liquid–vapor phase change processes, including boiling, evaporation, and condensation, play pivotal roles in a wide range of industrial applications. These phenomena are not only central to petroleum and chemical processes but also critically impact safe nuclear power operations. − In this context, understanding the energy transfer at the solid–liquid interface within two-phase thermal systems is essential. Quantifying parameters such as the critical heat flux (CHF) and heat transfer coefficient (HTC) are intrinsic to optimizing boiling and condensation processes, especially for efficient heat removal in compact devices.…”