Chemical analysis of refrigerant mixture

Chemical analysis of refrigerant mixture

Problem description:
As per proposed refrigerant mixture composition of azeotropic refrigerant mixture consisting 50wt% R-32 (CAS: 75-10-5) and 50wt% R-125 (CAS: 354-33-6) and 2 ionic liquid solvents are considered, namely [bmim][PF6] (CAS: 174501-64-5) and [emim][Tf2N] (CAS: 174899-82-2).

- As solvent, it is better to use IL1 than IL2; extreme caution is needed in their handling.
- R32 and R125 must not be released to the atmosphere and must not leak into closed space from any refrigeration system or storage tanks.
- Based on the properties, it is not clear which refrigerant is more dangerous? GWP should not be the only criteria to consider for their separation; R32 is highly flammable while R125 is not.
- In order to use solvent-based extractive distillation, R32 and R125 need to be compressed to liquid phase at close to normal temperature.
- As the solubility of R32 is much higher than R125, absorption with water could also be checked; in this case, see the Henry’s Law constants for the two gases in water.
- Solvents not soluble in water would favor R-125 while solvents soluble in water would favor R-32. Ionic liquids that are miscible in water could also be checked for absorption of R-32.
- Phase equilibrium properties for R-32 and R-125 in IL-solvents need to be measured and then used to regress selected model parameters (options: cubic EOS + NRTL; cubic EOS + UNIQUAC; PC-SAFT; ….); pure component vapor pressure data, properties needed by the equation of state used plus the NRTL or UNIQUAC model parameters. For energy balance, enthalpies from specific heats of liquid and vapor need to be calculated. Temperature dependent measured data such as vapor pressure, specific heats, density, etc., are available for the two refrigerants and can be obtained from PSE for SPEED Company. They are also available in other databases.

Important notice:
This report is only for private use and must not be shared with any third-party without prior permission from PSE for SPEED Company.