Measurement and Correlation of Vapor–Liquid Equilibrium for R124 (1-Chloro-1,2,2,2-Tetrafluoroethane)-NMP (N-Methyl-2-Pyrrolidone) and R124-DMF (N,N-Dimethylformamide) Mixtures

Abstract

Vapor–liquid equilibrium data of binary working pairs play a crucial part in the research of absorption process and absorption refrigeration technology. In this paper, the VLE data of binary mixtures, R124-NMP and R124-DMF, were measured in a temperature range from 303.15 to 363.15 K, using a VLE measurement apparatus. The activity coefficient model of five-parameter nonrandom two liquid (NRTL) was selected to correlate all the VLE data acquired by measurement. The maximum relative deviation of the pressure between the measurement data and calculated data for R124-NMP and R124-DMF were 3.80% and 3.27% respectively, and the average relative deviation of the pressure were 1.25% and 1.17% respectively. The correlated results coincide well with the measurement data and show that the VLE characteristics of R124-NMP and R124-DMF mixtures have a negative deviation from Raoul’s law. Comparing three absorbents, DMF, DMAC and NMP, the activity coefficient of R124 in DMF is largest, that in DMAC is second, and that in NMP is smallest.