Drop-in recycled refrigerant compositions having low net GWP replacing R-454B
A refrigerant composition is made up of approximately 72-74% difluoromethane, 7-8% pentafluoroethane, 1-3% carbon dioxide, and 17-19% 1,3,3,3-tetrafluoropropene. This mixture is formed from recycled difluoromethane and pentafluoroethane, which have a net global warming potential of 0. The method of preparing this refrigerant involves injecting a mixture of recovered refrigerants, including difluoromethane, pentafluoroethane, and chlorodifluoromethane, into the center of a distillation column. The top of the column yields a refrigerant composition of 90-92% difluoromethane and 8-10% pentafluoroethane. Chlorodifluoromethane is removed from the bottom of the column. This refrigerant composition is used to create a low global warming potential refrigerant that can be used as a drop-in replacement for R-454B.
1. A method of preparing a refrigerant composition, comprising:
injecting a mixture of reclaimed refrigerants into a center of a distillation column, the mixture of reclaimed refrigerants comprising reclaimed difluoromethane, reclaimed pentafluoroethane and reclaimed chlorodifluoromethane;
removing from a top of the distillation column a refrigerant mixture of about 90-92 wt % of the reclaimed difluoromethane and about 8-10 wt % of the reclaimed pentafluoroethane;
removing the reclaimed chlorodifluoromethane from a bottom of the distillation column; and
manufacturing the refrigerant composition from the refrigerant mixture removed from the top of the distillation column,
wherein the refrigerant composition comprises:
about 72-74 wt % difluoromethane;
about 7-8 wt % pentafluoroethane,
about 1-3 wt % CO 2 , and
about 17-19 wt % 1, 3, 3, 3-tetrafluoropropene.
2. The method of claim 1 , wherein injecting the mixture of reclaimed refrigerants into the center of a distillation column is performed at a temperature of about 140-150° F. at a pressure of about 400-420 psia.
3. The method of claim 1 , wherein removing from the top of the distillation column is performed at about 95-105° F. at a pressure of about 370-380 psia.
4. The method of claim 1 , wherein removing from the bottom of the distillation column is performed at about 140-150° F. at a pressure of about 375-385 psia.
5. The method of claim 1 , wherein the refrigerant composition comprises:
about 72.8 wt % difluoromethane;
about 7.2 wt % pentafluoroethane,
about 2 wt % CO 2 , and
about 18 wt % 1, 3, 3, 3-tetrafluoropropene.
6. The method of claim 1 , wherein the refrigerant composition has properties approximating a mixture of 68.9 wt % difluoromethane and 31.1 wt % 2, 3, 3, 3-tetrafluoropropene.
7. The method of claim 1 , wherein the refrigerant composition has a net global warming potential about 29% of that of a mixture of about 68.9 wt % difluoromethane and 31.1 wt % 2, 3, 3, 3-tetrafluoropropene.
8. The method of claim 1 , wherein the refrigerant composition has a theoretical boiling point of about −51° F.
9. The method of claim 1 , wherein the refrigerant composition has a liquid phase pressure of about 221 psia at 70° F. and a vapor phase pressure of about 198 psia at 70° F.
10. The method of claim 1 , wherein the refrigerant composition has a liquid phase density of about 1.02 g/cm 3 at 70° F. and a vapor phase density of about 0.043 g/cm 3 at 70° F.
11. The method of claim 1 , wherein the refrigerant composition has a liquid phase enthalpy of about 0.236 KJ/g at 70° F. and a vapor phase enthalpy of about 0.480 KJ/g at 70° F.
12. The method of claim 1 , wherein the refrigerant composition has a liquid phase entropy of about 6.2×10 −4 KJ/gR at 70° F.
13. The method of claim 1 , wherein the refrigerant composition has a vapor phase entropy of about 1.1 ×10 −3 KJ/gR at 70° F.
14. The method of claim 1 , wherein the refrigerant composition further comprises about 0.01-5 wt % lubricant.
15. The method of claim 14 , wherein the lubricant is selected from the group consisting of mineral oil, alkylbenzene oil and polyol ester.
16. The method of claim 14 , wherein the lubricant is an ester of at least one neopentyl polyol represented by the structural formula:
in which each R is independently selected from CH 3 , C 2 H 5 or CH 2 OH.
17. The method of claim 14 , wherein the refrigerant mixture further comprises at least one of an ultraviolet dye or a sealant.
18. The method of claim 1 , wherein the refrigerant mixture comprises about 91 wt % difluoromethane and about 9 wt % pentafluoroethane.
19. The method of claim 1 , wherein the refrigerant mixture contains less than 1.0×10 −18 wt % H 2 O.