Patent Number: 6,168,720

Title: Process for drying CH2F2 refrigerant utilizing zeolite

Abstract: Difluoromethane (R-32) is of current interest as a partial replacement for chlorodifluoromethane (R-22) refrigerant heretofore widely used in vapor compression refrigeration systems. R-32 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 potassium cation form of a zeolite A molecular sieve--with at least 60 percent of the sodium cations replaced with potassium ions, agglomerated with a clay binder, and pore-reduced to essentially exclude the adsorption of R-32 having essentially no reactivity with difluoromethane, and having a surface ratio of silicon to aluminum of less than about 1.7 mol/mol as determined by X-ray photoelectron spectroscopy--has been found to be an effective desiccant for refrigerants comprising difluoromethane.

Inventors: Lavin; Maryellen (Hightstown, NJ), Cohen; Alan P. (Highland Park, IL), Hurst; Jack E. (Leverkusen, DE)

Assignee: UOP LLC

International Classification: B01J 20/10 (20060101); B01J 20/18 (20060101); B01D 53/26 (20060101); C09K 5/04 (20060101); C09K 5/00 (20060101); B01D 015/04 ()

Expiration Date: 01/02/2018