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Vapor liquid equilibrium prediction of methanol–ionic liquid systems using UNIFAC model to select alternative working fluids of absorption cycle
Author(s) -
Li Jing,
Wang Keliang,
Lian Minglei,
Li Zhi
Publication year - 2018
Publication title -
asia‐pacific journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.348
H-Index - 35
eISSN - 1932-2143
pISSN - 1932-2135
DOI - 10.1002/apj.2281
Subject(s) - ionic liquid , unifac , chemistry , methanol , vapor pressure , absorption (acoustics) , thermodynamics , analytical chemistry (journal) , activity coefficient , chromatography , organic chemistry , materials science , aqueous solution , catalysis , physics , composite material
The purpose of this paper is to study the working fluids in absorption cycle containing methanol (CH 3 OH) as the refrigerant and the imidazolium ionic liquid (IL) as the absorbent. The UNIFAC model was implemented to correlate the published experimental vapor liquid equilibrium data of CH 3 OH–IL working fluids and 14 new group interaction parameters between CH 3 OH and ILs were obtained. Method reliability and applicability were evaluated by calculating the vapor pressures of five CH 3 OH–IL working fluids. The ILs contained 1‐methyl‐3‐methylimidazolium dimethylphosphate ([Dmim][DMP]), 1‐ethyl‐3‐methylimidazolium ethyl sulfate ([Emim][ES]), 1‐ethyl‐3‐methylimidazolium diethylphosphate ([Emim][DEP]), 1‐butyl‐3‐methylimidazolium dibutylphosphate ([Bmim][DBP]), and 1‐ethyl‐3‐ethylimidazolium diethylphosphate ([Eeim][DEP]). The average absolute relative deviations for the vapor pressures between the calculated results and the experimental data were 0.91%, 1.67%, 0.66%, 0.75%, and 2.1%, respectively. Then, the CH 3 OH–IL systems without experimental data were predicted. Comparisons of the vapor pressure and excess Gibbs function of the studied CH 3 OH–IL systems, CH 3 OH‐[Hmim][DEP] (1‐hexyl‐3‐methylimidazolium diethylphosphate) system, as an alternative working fluid, was found to have potential to improve the absorption cycle performance upon more research work.