Desorber and rectifier geometries for ammonia-water absorption systems; Part II: Mass transfer, flooding, and component performance

An experimental investigation of two compact counter-flow vapor generation units, for use in ammonia-water absorption systems, was conducted. The vapor generation units feature integrated desorber, analyzer, and rectifier sections. The branched tray design uses pool-boiling mechanisms in the desorption process, while the vertical column uses falling-film evaporation mechanisms. Experimental mass transfer coefficients for the desorbers of both concepts were quantified and compared with correlations from the literature, generally with poor agreement. The flooding limits of these counter-flow vapor generation units were investigated and agree well with available correlations. The experimental results from Part I of this study are used in this paper, Part II, to develop revised heat and mass transfer models that accurately predict component level performance. (C) 2020 Published by Elsevier Ltd.