Isothermal Vapor–Liquid Equilibrium of the Absorption Working Pairs (HFC-32 + DMETrEG, HFC-32 + NMP) at Temperatures from 293.15 to 343.15 K

Abstract

The working pairs of HFCs + organic absorption solvents are commonly used in absorption systems. In this work, the vapor–liquid equilibrium (VLE) data of HFC-32 + DMETrEG at (293.15–343.15) K and HFC-32 + NMP at (323.15–343.15) K were measured in a dual cycle apparatus. The VLE data were correlated by Antione-type equation, NRTL, and PR + MHV1 + NRTL model, respectively. The predicted VLE data showed a good agreement with the experimental VLE data. NRTL model was recommended to predict the VLE data and characteristic of solution for HFC-32 + DMETrEG and HFC-32 + NMP, compared to PR + MHV1 + NRTL model. The comparison of VLE characteristics for five binary mixtures (HFC-32 + DMETrEG, HFC-32 + NMP, HFC-32 + DMF, HFC-32 + DMAC, and HFC-32 + DMEDEG) was carried out. The compared results showed that the system pressures of HFC-32 + DMETrEG and HFC-32 + NMP were lower than other three mixtures, and the negative deviations from Raoult’s law of HFC-32 + DMETrEG and HFC-32 + NMP were larger than the others, which indicated that the two mixtures were more suitable as the working fluids for absorption system.

Vapor–Liquid Equilibrium for the Binary Systems 1,1,2,3,3,3-Hexafluoro-1-propene (R1216) + 2,3,3,3-Tetrafluoroprop-1-ene (R1234yf) and 1,1,2,3,3,3-Hexafluoro-1-propene (R1216) + trans-1,3,3,3-Tetrafluoropropene (R1234ze(E))

“…The analysis of uncertainty was similar to our previous researches. , Considering the error from PT25 (0.001 K), the error from Agilent (0.005 K), and fluctuations of bath temperature (0.01 K), the expanded uncertainty of temperature ( k = 2) was 0.03 K. Considering the error from pressure sensors (1.4 kPa), error from Agilent (0.002 kPa), and the repeatability error (2.0 kPa) at equilibrium, the expanded uncertainty of pressure ( k = 2) was 4.9 kPa.…”

“…The experimental apparatus, shown in Figure , was a recirculation system, which was similar to that in our published work . Compared to the previous apparatus, the vapor pump was removed, and the vapor sampling section was added for measuring the vapor composition by gas chromatography (GC) through the six-way valve.…”

Isothermal Vapor–Liquid Equilibria of the Absorption Working Pairs (R1234ze(E) + NMP and R1234ze(E) + DMETrEG) at Temperatures from 293.15 to 353.15 K

“…In this work, the uncertainty of temperature, pressure, and composition needed to be analyzed. The detailed processes of uncertainty analysis (temperature and pressure) were shown in our previous work. , The expanded uncertainty of temperature ( k = 2) was U ( T ) = 0.074 K. The expanded uncertainty of pressure ( k = 2) was U ( p ) = 2.0 kPa. For the calculation of composition uncertainty, the uncertainty of the peak area ratio during the experiment could be calculated according to the experimental data using the Bessel formula.…”

“…The detailed processes of uncertainty analysis (temperature and pressure) were shown in our previous work. 20,21 The expanded uncertainty of temperature (k = 2) was U(T) = 0.074 K. The expanded uncertainty of pressure (k = 2) was U(p) = 2.0 kPa. For the calculation of composition uncertainty, the uncertainty of the peak area ratio ( )…”