IMPROVED ENERGY EFFICIENCY IN ABSORPTION HEAT-PUMP THROUGH PROCESS MODIFICATION - PART I - SOLVENTS FOR LIQUID-LIQUID-EXTRACTION OF AMMONIA-WATER MIXTURE

The isothermal liquid-liquid extraction process has been proposed as a feasible replacement for the non-isothermal separation process employ ed in the conventional ammonia-water absorption heal pump to improve t he energy efficiency of the heat pump system. Of the two possible extr action schemes (based on which component of aqua ammonia is extracted) , the ammonia-extracted scheme was found more suitable on the basis of availability of extract solvents whose use engender relatively lower energy consumption and loss. UNIQUAC was used to evaluate the relevant thermodynamic data, while capacity and selectivity diagrams were used to select appropriate extract solvents for separation of the ammonia- water mixture. Nitrobenzene, toluene, m-xylene, ethylbenzene and styre ne were found to be suitable solvents in the extraction process. (C) 1 998 Elsevier Science Ltd. All rights reserved.