| Absorption heat pump is an important equipment for recovering industry waste heat.It has characteristics of high efficiency,energy saving and environmental protection.With economic development,strengthening of people's awareness of environmental protection, there has been a growing interest in heat pump technology.The development of new working pairs has also been paid more and more attention.Ionic liquid is a kind of room temperature melted salt which consists of organic cations and inorganic anions.They have many advantages such as a negligible vapor pressure,strong solubility in many organic substances,and stable in a large temperature range.As green solvents,ionic liquids have a potential application in chemical industries in recent years.In this paper,binary systems containing ionic liquids are considered as new working pairs in absorption heat pumps.[EMIM][DEP]was synthesized in the lab.Vapor pressures for the three binary systems([EMIM][DEP]+H2O/C2H5OH/CH3OH respectively) with different contents of[EMIM][DEP]were measured at different temperatures,The experimental data all showed a considerable negative deviation from Raoult's law.The vapor pressure data were correlated by NRTL model.NRTL parameters were obtained.The average deviation between experimental data and correlated ones were 2.73%,2.36%,1.26% respectively.The mixing heat(HE) for those three systems were also measured,the HE data all showed that the mixing process were exothermic process.Heat capacities for the three systems were also measured in this paper.In the experiment,Densities and viscosities for the three binary systems mentioned above were measured at different temperature(From 25℃to 50℃).The experimental data of densities showed a linear relationship against temperature.The viscosities of[EMIM][DEP] were obviously greater than those of H2O,especially when the temperature was low.At the temperature of 298.15K the viscosity of[EMIM][DEP]is about 301 times of H2O.Therefore when H2O/C2H5OH/CH3OH was added into[EMIM][DEP],the viscosity of the mixture decrease sharply.And as expected,for the system at the same composition,the viscosity of the system decreases sharply with the increase of the system's temperature.The experimental viscosities were correlated using Arrhenius equation.The results indicated that the Arrhenius equation can be used to describe the viscosity of the binary system containing [EMIM][DEP]+H20 well.The average deviation between experimental data and correlated ones were 2.42%,1.86%,2.15%respectively.The results showed that ionic liquid[EMIM][DEP]+H2O/C2H5OH/CH3OH have potential as working pairs.
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