Process for drying CH.sub.2 F.sub.2 refrigerant utilizing zeolite
AssigneeUop LLC
InventorsMaryellen Lavin, Alan P. Cohen, Nanette Greenlay, Thomas R. Cannan, Richard J. Hinchey
Life of this patent
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Abstract
Difluoromethane (R32) is of current interest as a partial replacement for chlorodifluoromethane (R22) refrigerant heretofore widely used in vapor compression refrigeration systems. R32 has, however, proved to be more reactive than is desirable with the zeolite A adsorbent-desiccant compositions used in such systems to prevent corrosion and freeze-up problems. The sodium cation form of a zeolite having the crystal structure of zeolite B is found to be an effective adsorbent for that purpose and to be significantly less reactive with the R32.
Claims5
In a refrigeration process wherein a refrigerant fluid comprising difluoromethane is cycled within a closed system and is alternately vaporized and condensed in a manner to produce cooling, the improvement which comprises incorporating within the closed system containing said difluoromethane and in contact therewith as a desiccant, an activated sodium cation form of a microporous zeolitic molecular sieve having the crystal structure of zeolite B, a framework Si/Al.sub.2 molar ratio of at least 2.5, and in the fully hydrated state an x-ray diffraction pattern the major d-spacings of which are
- ______________________________________ Relative d, .ANG. Intensity ______________________________________ 7.10 .+-. 0.1 S-VS 4.97 .+-. 0.1 M-S 4.10 .+-. 0.1 S-VS 3.18 .+-. 0.1 S-VS. ______________________________________
Dependencies are inferred from the claim text.