Extractive distillation and pressure-swing distillation for THF/ethanol separation

Abstract

BACKGROUND During the synthesis of a liquid crystal monomer, an effluent including tetrahydrofuran(THF) and ethanol is produced. Since THF and ethanol are both important solvents used in the chemical industry, it is necessary to separate the mixture of THF and ethanol for reuse. However, it is hard to effectively separate the mixture via simple distillation because a minimum azeotrope is formed in the binary system. RESULT Extractive distillation and pressure‐swing distillation are adopted to separate the mixture and carefully optimized to achieve minimization of the total annual cost (TAC). A comparison between the two processes is carried out. Pressure‐swing distillation is used to separate mixtures of THF and ethanol with various compositions. CONCLUSION The results indicate that pressure‐swing distillation performs better than extractive distillation from the standpoint of both economic considerations and product purity. The feasible sequence of high and low pressure of two columns in a pressure‐swing distillation is related to the feed composition. © 2014 Society of Chemical Industry

Separation of a ternary mixture with multiple azeotropes via pressure‐swing distillation

“…It does not cause the same potential problem of the added component compared to extractive distillation . Up to now, a considerable amount of literature has investigated the double‐column PSD process for separating the binary azeotropic system in terms of steady simulation and dynamic control . However, only a limited number of studies on the triple‐column PSD process for the separation of ternary multi‐azeotropic mixtures have been reported and gained extensive attention …”

“…1,2 Up to now, a considerable amount of literature has investigated the double-column PSD process for separating the binary azeotropic system in terms of steady simulation and dynamic control. [3][4][5][6][7][8][9][10] However, only a limited number of studies on the triple-column PSD process for the separation of ternary multi-azeotropic mixtures have been reported and gained extensive attention. [11][12][13][14] The mixture of tetrahydrofuran (THF), ethanol and water is often encountered in the chemical industry, such as the norgestrel production or the process of dehydrating 1,4-butanediol.…”

Evaluation of ionic liquid separation ability for the benzene–methanol mixture by extractive distillation

“…Aspen Plus is widely used in the simulation of extractive distillation process, but due to the complex and uncommon structure of some ILs, their thermodynamic properties are not in the database of the Aspen Plus software, so a database belonging to ILs must be established. The thermodynamic properties required include boiling point ( T b ), critical properties (critical pressure, P C ; critical volume, V C ; critical compressibility factor Z C ; critical temperature, T C ), acentric factor (ω), ideal gas heat capacity (), liquid saturated vapor pressure ( P vap ), and enthalpy of vaporization ( Δ vap H ).…”

Thermal coupled extractive distillation sequences with three entrainers for the separation of azeotrope isopropyl alcohol + diisopropyl ether

“…Currently, special distillations such as extractive distillation (ED), heterogeneous azeotropic distillation (HAD), pressure‐swing distillation (PSD) and reactive distillation (RD) are adopted to separate such azeotropes. Arifin et al .…”