Process design of carbon dioxide and ethane separation using ionic liquid by extractive distillation

J of Chemical Tech & Biotech

Feng

et al. 2021

BACKGROUND: The binary benzene-n-propanol azeotrope can be formed in chemical production. Extractive distillation is an important azeotrope separation technology and an ionic liquid is a type of excellent entrainer. Aspen Plus software was used to simulate the extractive distillation process. The separation performance of ionic liquids was evaluated in terms of total annual cost of the extractive distillation process. The separation mechanism of the azeotrope was quantitatively explained using intermolecular interaction energy. RESULTS: The thermodynamic properties databases of 1-octyl-3-methylimidazolium acetate, trioctylmethylammonium acetate and 1-decyl-3-methylimidazolium acetate were established in Aspen Plus software. The extractive distillation process was established through combining the thermodynamic properties of the three ionic liquids and the vapor-liquid equilibrium data of benzene-n-propanol-ionic liquid. The optimal operating conditions were obtained by minimizing the total annual cost of the separation process through a sequential iterative method. The interaction energy was calculated using density functional theory through Gaussian 09 software and used to explain the principle of the benzene-n-propanol azeotropic system separation.CONCLUSIONS: 1-Octyl-3-methylimidazolium acetate has the best separation performance among the three ionic liquids. The interaction energy can be used to screen and design ionic liquids in the process of benzene-n-propanol extractive distillation separation.

Section: Calculation Of Il Propertiesmentioning

confidence: 99%

Design and optimization of extractive distillation of benzene–n‐propanol with ionic liquid as entrainer

J of Chemical Tech & Biotech

Feng

et al. 2021

“…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 (

C_{normalP}^{0}

), liquid saturated vapor pressure ( P vap ), and enthalpy of vaporization ( Δ vap H ).…”

Section: Simulation Of Extractive Distillation Processmentioning

confidence: 99%

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

J of Chemical Tech & Biotech

Feng

et al. 2019

BACKGROUND Benzene–methanol azeotrope can be formed at atmospheric pressure. Extractive distillation is widely used in the separation of azeotrope. The key factor for extractive distillation is the selection of entrainer. The minimal total annual cost of extractive distillation process can be used as objective function to evaluate the separation performance of ionic liquid entrainer. Intermolecular interaction energy can be used to analyze separation mechanisms. RESULT An Aspen Plus software database belonging to the three ionic liquids 1‐hexyl‐3‐methylimidazolium acetate, 1‐octyl‐3‐methylimidazolium acetate and 1‐decyl‐3‐methylimidazolium acetate was established. The minimal total annual costs of three extractive distillation processes for the separation of benzene–methanol mixture with different ionic liquids were obtained by sequential iterative method. The feed rate of entrainer was also obtained under the optimized conditions. Among the three extractive distillation processes with different ionic liquid, the total annual cost and the entrainer feed rate of the extractive distillation process with 1‐hexyl‐3‐methylimidazolium acetate as entrainer are the smallest. The intermolecular interaction energies in the ternary system of benzene–methanol–ionic liquid were obtained using the Gaussian 09 software package based on the density functional theory. The separation mechanisms and the extractive distillation process of benzene–methanol azeotrope with ionic liquid as entrainer was interpreted by the intermolecular interaction energy. CONCLUSION The results show that the separation ability of 1‐hexyl‐3‐methylimidazolium acetate is higher than that of 1‐octyl‐3‐methylimidazolium acetate or 1‐decyl‐3‐methylimidazolium acetate. Intermolecular interaction energy analysis can be used in the screening and design of ionic liquid entrainer. © 2019 Society of Chemical Industry

“…Moreover, CO 2 and ethane molecules have a strong repulsive force against each other, forming the lowest‐boiling‐point azeotrope, therefore, it is complicated to separate CO 2 from hydrocarbon in natural gas 11, 12. Many researchers reported on breaking the CO 2 ‐C 2 H 6 azeotrope to achieve removal of CO 2 from natural gas 13–23.…”

Section: Introductionmentioning

confidence: 99%

Selection of State Equation and Innovative Process Design for Removing CO₂ by Azeotropic Distillation

Zhang

Fan³

et al. 2021

Chem Eng & Technol

A thermodynamic consistency test was performed on the gas‐liquid equilibrium data of three binary mixtures, namely, CH4‐C2H6, CH4‐CO2, and C2H6‐CO2, measured by Wei and Brown at three different temperatures to verify the reliability of the data. Peng‐Robinson (PR), Redlich‐Kwong (RK), and Soave‐Redlich‐Kwong (SRK) equations of state combined with Margles mixing rules were used to fit the gas‐liquid equilibrium data of these three models. The results indicate that the PR‐Margles mixed model can make the average absolute deviation of test data and calculated data pressure and vapor fraction less than 0.19 and 0.0025, respectively, which is superior to RK‐Margles and SRK‐Margles mixed models. Finally, an azeotropic distillation method with C2H6 as entrainer for removing CO2 from natural gas was explored and optimized.