Predictions of the vapor-liquid equilibrium data for low-GWP Hydrofluorocarbons + polyethylene-glycol dimethylether solvents by modified UNIFAC model

Xiao Zhang,Liang Cai,Jingyi Qiao,M.S Tahir,L Xing

doi:10.1051/e3sconf/202126702052

Abstract

The working fluids are crucial for developing the absorption refrigeration system. Our previous work has proposed three novel working pairs, which uses the low-GWP HFCs (R32, R152a and R161) as the refrigerants and the polyethylene-glycol dimethylether solvent DMETEG as the absorbent. To explore the VLE behaviors of HFCs in other longer chain structures of polyethylene-glycol dimethylether solvents, the modified UNIFAC (Dortmund) model was applied for prediction. The previous binary parameters showed large deviations from the experimental data. Then the new binary parameters were obtained by regression. For R32+DMEDEG and R152a/R161+DMETrEG, the prediction ARAD results were reduced from 17.13%, 24.06% and 12.48% to 3.71%, 2.61% and 6.86%, respectively. Finally, the VLE data of R161 + PGDE at the temperatures of 293.15-343.15K were predicted.

Highlights

The absorption refrigeration system is of great significance for the energy utilization, especially the waste heat source
1400 1200 modified UNIFAC with new parameters modified UNIFAC with previous parameters R161+DMEDEG at 293.15K R161+DMETrEG at 313.15K R161+DMETEG at 343.15K
For the five binary mixtures used for regression, the average relative absolute deviation (ARAD) between the experimental and calculated pressures using the new parameters is about 4.37%, while the modified UNIFAC

Summary

Introduction

The absorption refrigeration system is of great significance for the energy utilization, especially the waste heat source. It can greatly promote my country's process of achieving carbon peaking or carbon neutrality. A lot of researchers have recently explored the novel binary working pairs using the low-GWP Hydrofluorocarbons (HFCs, i.e., R32, R152a, and R161) as the refrigerant and the organic solvents as the absorbent. Their vapor-liquid equilibrium (VLE) data were measured by the static-analytical method. The VLE data of R161 + DMAC/NMP at a temperature of 293.15-353.15K were measured and correlated by Jing et al[3]. Because of the atmospheric lifetime of only 11 days and the 100-year GWP about 4 [4], the extremely environmentally friendly R1234yf was explored by Fang et al [5] for its solubility in NMP and DMETrEG by using a dual-cycle experimental device

Methods

Results

Conclusion