The Thermodynamic Properties Of Ternary Working Fluids Of Ionic Liquid [BMIM][DBP] And Water+Alcohol

Absorption heat pump (AHP) is an effective equipment for recovering industry waste heat, which has the characteristics of high efficiency and environmental protection. Its operational performance largely depends on the property of working pairs. LiBr-H2O and NH3-H2O are widely used as working pairs which have the following shortcomings:serious corrosion to the equipment, crystallization in high concentration, high operation pressure, toxicity, et al. Therefore, researches on new working pairs have received an increasing attentions.Ionic Liquid (IL) has good physical and chemical properties, such as thermal stability, negligible vapor pressure, wide liquid range and strong solubility in many organic or inorganic substances. So, it is possible to be used as the absorbent of cool agent in AHP. In order to promote its industrial applications as working pairs in AHP, vapor-liquid phase equilibrium data,excess enthalpy (HE) and specific heat capacity (Cp) are vital important, and should be measured. In this paper, vapor pressure, excess enthalpy (HE), specific heat capacity (Cp) for three binary systems and two ternary systems composed of ionic liquid (IL)1-butyl-3-methylimidazolium dibutylphosphate ([BMIM][DBP]) and water, and methanol or ethanol were measured.In this dissertation [BMIM][DBP] was synthesized, purified by extraction and characterized by H1NMR. The vapor pressures of the three binary solutions at different mole fraction of ionic liquid were measured by using the static method and the two ternary systems were measured by quasi-static ebulliometer. The vapor pressure data of three binary systems containing ILS studied were correlated by traditional NRTL model of non-electrolyte solution and the average deviations were3.19%,2.42%and2.95%, respectively. The fitted binary NRTL parameters can be used to predict the vapor pressure of the two ternary systems, and the average deviations were2.98%and2.77%, respectively. So NRTL equation could be used to correlate systems containing ionic liquid. The excess enthalpies (HE) of three binary systems and three ternary systems were measured at298.15K with different IL concentrations. The HE data were negative, which means the processes of mixing [BMIM][DBP] with water, methanol or ethanol are exothermal. The experimental data were correlated and calculated by NRTL model and UNIQUAC model. The experimental data of heat capacities for the two ternary systems were measured at mole fraction of0.2and0.4of IL. The average deviations were0.67%and0.45%, respectively. It shows that the heat capacities decreased with the increase of molar fraction of [BMIM][DBP] at the same temperature and slightly increased with the increase of temperature at the same IL concentration.Consequently, the two ternary solutions containing ionic liquid,[BMIM][DBP]+H2O+CH3OH/C2H5OH have the potential as working fluids from thermodynamics angle.