SF-98-16-1 (RP-793) -- Test Method for Inorganic Acid Removal Capacity of Desiccants Used in Liquid Line Filter Driers PDF

For more than 40 years, desiccants have had the vital role of maintaining refrigerant systems in a dry state. For this research, a small bench top, refrigerant flow-through, airless test instrument was constructed and used to accurately measure the inorganic acid uptake and determine the equilibrium of circulating hydrogen chloride (HCl) in refrigerants. The research examined circulating chloride ion isotherms at 75°F (24°C) and 125°F (52°C) with anhydrous HCl in refrigerant. The HCl was circulated through the system in two refrigerants, R-12 and R-22, containing two moisture levels of 10 ppm and 60 ppm (±5 ppm). Evaluations were performed on four desiccants: (1) 3A molecular sieve beads, (2) 4A molecular sieve beads, (3) aluminum trihydrate type D alumina beads, and (4) silica gel granules. Unadsorbed circulating HCl was analyzed as chloride ion using a modified Volhard method.

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