Ammonia-fired chemically recuperated gas turbine: Thermodynamic analysis of cycle and recuperation system

Ammonia is one of the prospective alternatives to hydrocarbon fuels. Currently, there are projects for developing of ammonia fired gas turbines up to 40 MW. The addition of thermochemical exhaust gas heat recuperation systems to ammonia-fired gas turbines could be a promising way to increase their efficiency. In this paper, the concept of an ammonia-fired chemically recuperated gas turbine (CRGT) is thermodynamically analyzed. Gas turbine with thermochemical recuperation by ammonia decomposition is analyzed via Aspen HYSYS for a wide range of operating parameters: turbine inlet temperature of 700-1300 degrees C, the pressure of 6-21 bar. The thermochemical exhaust heat recuperation system is recovering the exhaust heat in a reformer (for the endothermic reaction of ammonia decomposition), a heater (to preheat ammonia to the temperature of the decomposition reaction), and a regasifier (for regasification of liquid ammonia). The thermochemical exhaust heat recuperation system makes it possible to recover up to 43% of exhaust heat. The maximum efficiency of CRGT is observed at 9 bar for T-in = 700 degrees C; 12 bar at T-in = 800 degrees C; 15 bar at T-in = 900 degrees C; 18 bar at T-in = 1000 degrees C. In the temperature range above T-in > 1000 degrees C, when the pressure rises above 15 bar, the efficiency does not increase significantly. (C) 2022 Elsevier Ltd. All rights reserved.

Automated summary

Ammonia is a prospective alternative to hydrocarbon fuels, with projects for developing ammonia-fired gas turbines up to 40 MW. Thermochemical exhaust gas heat recuperation systems can increase efficiency in ammonia-fired gas turbines, with the potential to recover up to 43% of exhaust heat.