3461 (RP-591) -- Absorption of Ammonia into Water PDF

ANSI/ASHRAE Standard 15-1989 suggest a procedure for trapping ammonia when it is released from a refrigeration system. The procedure utilises one gallon of standing water for every pound of ammonia in the system. Alternatively, the standard suggests that ammonia-water mixers operate under the conditions of 2 gpm of water per lb/min of ammonia. Experiments conducted to evaluate these procedures used a receiving vessel in which water or a water spray was used to absorb ammonia. An ammonia distributor utilising stainless steel fabric cloth was constructed to thoroughly mix the ammonia and standing water. Relative to the ammonia-water ratios recommended by, ANSI/ASHRAE Standard 15-1989, 90% of the released ammonia vapour was absorbed in standing water. With the release of liquid ammonia to standing water, all the ammonia was absorbed. Use of the ammonia-water mixer with a water spray absorbed 86% of the released ammonia vapour. Analytical models for ammonia absorption predict measured absorption quantities to within plus or minus 15%. Desorption of ammonia trapped in water was experimentally observed to result in the decrease of ammonia concentration in the liquid mixture by a factor of about 2 in 50 days. These results are valid only for the experimental apparatus configuration of this study.

KEYWORDS: absorption refrigeration, refrigeration, leaking, ammonia, water, calculating, measuring, experiment