Exergy and Pinch Analysis of an Advanced Ammonia-Water Coal-Fired Power Cycle

Abstract An exergy analysis of a power system identifies the location, type, and magnitude of losses of the potential to do work, while a pinch analysis examines a heat exchange network efficiency. A complete exergetic analysis of Kalina cycle System 19, an advanced binary fluid (ammonia-water working fluid) power cycle, is presented along with a combined pinch/exergy analysis of the Kalina cycle heat exchanger/furnace/cooling utility network. The Kalina cycle System 19 has a net thermal efficiency (net work/furnace duty) of 43% (HHV), a furnace exergetic efficiency of 77.4%, and an exergetic plant efficiency (net work/exergy of flue gas) of 61.6%. Most of the exergy losses (21.5%) occur in the furnace; 9.6% of the exergy is lost in pumps, turbines, throttles, mixers, and the stack gas; and 7.3% of the exergy loss occurs in heat exchanger/cooling utility network. The System 19 total exergy loss in all heat exchange equipment is only 7.2% greater than its minimum value. Thus, the analysis indicates that the Kalina cycle System 19 is efficiently designed.