Study On Vapor-liquid Equilibria Of Alternative Mixture Containing HFO

Due to environmental protection requirements,it is urgent to look for new environmentally friendly alternative refrigerants.HFCs and HCs are the main refrigerants currently used.However,most HFCs have relatively high GWP values,and HCs are inflammable and explosive.HFOs are environment-friendly refrigerant with low GWP,however,the disadvantage in enthalpy of evaporation.it is believed that the mixing of two refrigerants mayoffer a good alternative to pure substances.It is expected thatsuch mixtures can meet the requirements of high cycle efficiency,be environmentally friendly and not dangerous forhuman beings.Phase equilibrium properties are extremely important for the mixtures.Therefore,phase equilibrium properties of the binary mixtures of HFCs and HCs combined with HFOs were studied in this work.Vapor-liquid equilibrium data were collected for seven binary HFOs/HFCs and six binary HFOs/HCs system.The experimental VLE data were fitted using SR equation of state together with vdW mixing rule,PR equation of state together with vdW mixing rule,PR equation of state together with HV mixing rule and NRTL model,PR equation of state together with MHV1 mixing rule and NRTL model,and PR equation of state together with MHV1 mixing rule and Wilson model for these 13 systems.For the average pressure relative deviations and the average mole fraction absolute deviations of vapor phase between the calculated values and the experimental data,the SRK+vdW model are 0.74% and 0.0042,respectively,the PR+vdW model are 0.41% and 0.0042,respectively,the PR+HV+NRTL model are 0.27% and 0.0038,respectively,the PR+MHV1 +NRTL model are 0.31% and 0.0038,respectively,the PR+MHV1+ Wilson model are 0.26% and 0.0035,respectively.The results show that the PR equation of state is superior to the SRK equation of state.After selecting the PR equation of state and the mixing rule of the MHV1,the two activity coefficient models have little effect on the calculation accuracy.For non-ideal HFOs/HCs system is applied,the calculation accuracy of the MHV1 mixing rule and the HV mixing rule is higher than that of the vdW mixing rule,and for non-ideal weak HFOs/HFCs system,the three mixing rules have the same accuracy.The binary interaction coefficients were fitted to a model related to critical parameters and acentric factors.The vapor-liquid phase equilibrium data of 14 HFOs binary mixtures were calculated.The results show that for HFO-1234ze(Z)+HC-600 a systems and HFO-1234ze(Z)+HC-290 systems,the average relative pressure deviation of is 5.06%,and the average absolute more fraction deviation of vapor phase is 0.0172.The remaining 12 binary mixtures are 0.72% and 0.0045,respectively.