Conception and thermo-economic performance investigation of a novel solid oxide fuel cell/ gas turbine/Kalina cycle cascade system using ammonia-water as fuel

In order to develop a zero-carbon, high-efficiency and low-cost energy system, the conception of an innovative ammonia-water fueled solid oxide fuel cell (SOFC) - gas turbine (GT) - Kalina cycle (KC) cascade power system is proposed. The performance superiority of novel cascade system is verified by comparing with SOFC system using anode off-gas recycle (AOR). The influence of system key operation parameters including fuel ammonia mass fraction on novel system total energy efficiency and levelized cost of electricity (LCOE) is revealed. The rapid prediction and multi-objective optimization of novel system thermo-economic performance are conducted based on artificial neural network - multi-objective Harris hawks optimizer (ANN-MHHO). The results show that the total energy efficiency and LCOE of novel ammonia-water fed SOFC-GT-KC system are 12.92% higher and 8.91% lower than the SOFC system using AOR under preliminary condition, respectively. Parametric analysis reveals that fuel ammonia mass fraction presents a more significant effect on novel system thermo-economic performance than cell stack fuel utilization ratio. A high cell stack fuel utilization ratio of more than 0.64 is not conducive to improving novel system economic performance. The novel system LCOE reaches the minimum of 0.13807 $/kWh at SOFC operation pressure of 9.5 bar. The multi-objective optimization results demonstrate that the novel system total energy efficiency is increased by 1.14% and LCOE is reduced by 1.23% under optimal condition compared with preliminary condition. The novel system LCOE is more sensitive to ammonia price than interest rate.