Cycle humidification is an interesting and effective tool to increase the operational flexibility of micro Gas Turbines (mGTs). However, considering the future fuel diversification towards emission reduction and security of supply, it is essential to identify what the impact of the fuel is on the potential for cycle humidification. To determine this impact, in this paper, we present the results of a black box analysis towards this identification, using 2nd law analysis. Additionally, several advanced humidified cycles concepts have been simulated to assess their sensitivity towards fuel alteration. Black box results indicated that going towards hydrogen has no major impact on the cycle performance, while syngas clearly limits the potential: only injection up to 106 g/s is possible compared to the 123 g/s in the hydrogen case, leading to reduced electric efficiency of 38% compared to the 41% in the latter case. A similar observation was made when considering the specific humified cycles, where the preheated water injection option showed to be the best performing cycle. For all cases, however, using syngas led to a reduced cycle performance. Finally, none of the cycles could exploit the full black box potential and hence future work consists in the identification of the impact of fuel alteration on the more advanced humidified cycles, in an attempt to reach the full potential.
Keywords micro gas turbine, humidification, fuel diversification, exergy analysis