Research And Development Of Absorption Refrigeration Working Pair With [Li(TX-7)]SCN As Absorbent

Absorption refrigeration is a refrigeration technology driven by low-grade heat such as industrial waste heat and power plant waste heat.It can effectively alleviate my country’s energy pressure.The traditional absorption refrigeration（heat pump）system uses LiBr/H₂O and H₂O/NH₃ as the refrigerant pair.Based on the influence of the refrigerant on its physical and chemical properties,the system has high temperature corrosion,low temperature crystallization,and distillation degradation in practical applications,etc.Ionic liquid is a new type of green solvent,which can be miscible with most refrigerants,has a wide range of liquid range,is non-corrosive,has good thermal stability,and is an ideal absorbent.Ionic liquid refrigerants can solve the problems of traditional absorption refrigeration systems,and are currently a research hotspot in academia.This article focuses on a new type of ionic liquid with metal chelating cations[Li（TX-7）]SCN to investigate the vapor-liquid equilibrium properties and thermophysics of the[Li（TX-7）]SCN/H₂O working fluid pair The nature and cycle characteristics of the absorption system.The specific work is as follows:The[Li（TX-7）]SCN/H₂O solution vapor-liquid equilibrium measurement device was designed and built,and the saturation of the[Li（TX-7）]SCN/H₂O solution at the temperature of 283.15～443.15K was measured by the static method.Vapor pressure,and fitted the measurement data with the NRTL model.The average relative deviation was 0.027.The fitted data was used to draw the P-T-x diagram of[Li（TX-7）]SCN/H₂O solution.Finally,the measurement data was compared with other working fluids.The literature data of the saturated vapor pressure of the solution was compared.The results show that the saturated vapor pressure of[Li（TX-7）]SCN/H₂O binary solution is much lower than that of other ionic liquid-type working fluids.Ionic liquid[Li（TX-7）]SCN has good absorption capacity for water.A differential scanning calorimeter（DSC 200 F3）was used to measure the specific heat capacity of the ionic liquid[Li（TX-7）]SCN at a temperature of T=273.15～423.15K,and an empirical correlation was established.The Wilson model is used to correlate the activity coefficients of the[Li（TX-7）]SCN/H₂O solution components to predict the excess enthalpy of the binary solution,and the specific enthalpy of the binary solution is calculated from the predicted value,and the[Li（TX-7）]SCN/H₂O thermodynamic model is established.Under normal temperature conditions,the thermal conductivity of[Li（TX-7）]SCN/H₂O solution at different molar concentrations was measured using the improved 3ωtechnology,and the Random mixing model was used for correlation.Based on the law of conservation of energy and law of conservation of mass,a theoretical cycle model of single-effect absorption refrigeration（heat pump）with[Li（TX-7）]SCN/H₂O as the refrigeration working fluid pair is established.The theoretical cycle characteristics of the simulation calculations have been carried out.The influence of different operating temperatures of various components on the performance parameters of the system is studied,and the performance parameters of other absorption systems are compared.The research results show that the performance of the[Li（TX-7）]SCN/H₂O system is better than that of the[mmim]DMP/H₂O system under refrigeration conditions,and it is suitable for working conditions with lower absorption temperature and higher evaporation temperature.Under heat pump conditions,the performance of the[Li（TX-7）]SCN/H₂O system is better than that of the LiBr/H₂O system,which is suitable for working conditions with lower generation temperature and lower evaporation temperature.