Design and performance prediction of chemically recuperated ammonia-based power generation

In the energy transition from fossil to carbon-neutral fuels, ammonia (NH3) appears as a promising energy carrier for power generation through a combined cycle. However, the low reactivity of NH3 leads to operational limitations due to flame stability issues. Mixing NH3 with hydrogen (H2) from the chemical recuperation process could improve flame stability and widen the combined cycle's operational range. This paper investigates the performance of NH3-based combined cycle power generation with an NH3 cracking facility. The proposed combined cycle is evaluated using the process simulation method on a steady-state operation. The NO emission of NH3 and H2 co-combustion is modeled using a chemical reactor network. Emission modeling limits the operational combustion temperature to 1500 degrees C, higher than which will result in NO emission higher than the admissible value of environmental regulation (100 ppm dry, 15 % O2 basis). Results show that NH3 cracking coupled with exhaust gas recirculation enables the gas turbine to operate at 48.1-49.3 % efficiency in a relatively lean equivalence ratio interval of 0.60-0.68; hence, improving the operational range of combined cycle that satisfies both NO emission restriction and flame stability criteria.