Mass and heat transfers during absorption of ammonia into ammonia water mixture

An experimental study has been carried out to estimate mass transfer rate during absorption of ammonia vapor into ammonia-water liquid mixture and to measure temperature changes in both liquid and vapor bulks at two pressure differences of 380, and 50 kPa. Effect of ammonia initial concentration in the liquid mixture upon mass transfer rate has been investigated. Superheated ammonia vapor was allowed to enter a test cell to be absorbed, and the measured pressure drop during absorption was converted to ammonia-absorbed mass by means of ideal gas equation. Mass transfer rate was also estimated by means of interface heat flux, which was estimated by applying inverse heat conduction problem solution. It has been found that with an increase in ammonia initial concentration in an ammonia-water liquid mixture, mass transfer rate decreases until there is almost no absorption when ammonia initial concentration is about 60 %. Also it has been found that considerable amount of the heat, which is released due to absorption at the interface between the liquid and vapor bulks, transfers into the vapor bulk. (C) 2002 Elsevier Science Ltd.