Micro gas turbine fed by ammonia with steam injection: Performance and combustion analysis

This work aims to investigate the possibility of burning ammonia directly in a micro gas turbine (mGT) from a turbomachinery and thermodynamic perspective. A simulation algorithm consisting of a set of equations describing the behavior of the heat exchangers, combustor, turbomachines, and other auxiliary devices have been used to evaluate the performance of a 3.2 KWe mGT fueled by ammonia. In addition, this study has looked into how the mGT performance characteristics are affected by steam injection in the combustion chamber. Steam injection can provide more power and efficiency at the rated rotational speed. An additional algorithm utilizing Cantera’s library has been developed to study combustion kinetics and assess the effect of steam injection on MGT emissions when using ammonia as fuel. With the STeam Injected Gas Turbine (STIG) cycle taken into consideration, the results indicate that the maximum mass flow rate of steam produced by recovering the heat of the flue gas can be 1.5 g/s, depending on the temperature at the pinch point. Analyzing the mGT’s performance, when ammonia was fed and 1.5 g/s of steam was injected, the fuel’s mass flow rate dropped, reducing the amount of power consumed by the fuel compressor. As a result, there is a significant gain in electric power and efficiency. Regarding the pollutants’ emission, the concentration of NO x was reduced by 36%. Moreover, steam injection improved combustion efficiency as the unburnt NH 3 and H 2 reduced 86% and 28%, respectively, at the combustor outlet. Adopting the steam injection technique also increases system flexibility, as the released heat can be used to produce steam, which improves electric performance and adds flexibility in the power-to-heat ratio of the mGT. • Ammonia offers carbon-free combustion but with high NOx emissions. • Ammonia lowers efficiency by 5.16%, but steam injection boosts it by 7.8%. • Steam injection reduces NOx by lowering combustion temperatures. • Steam injection boosts power, efficiency, and cuts unburned NH 3 , and H 2 . • Ammonia-fed mGTs are viable with steam injection for carbon-free energy.