Numerical prediction on thermal performance and emission characteristics of Ammonia fueled swirl stabilized burner toward gas turbine nozzle considering in-situ SNCR with axial multi-staging strategy

Ammonia, as the carbon-free fuel has been considered an alternative energy source in large-scale industrial facilities owing to its high energy density and characteristics of hydrogen carrier. However, Ammonia fuel requires optimized combustion conditions to improve combustion efficiency and NO_x reduction technologies due to its low flame speed and fuel NO_x formation during combustion process. To solve these issues, cascaded role of Ammonia as fuel and reducing agent can be efficiently used during combustion process.

In the present study, selective non-catalytic reduction (SNCR) is introduced with axial multistaging scheme under ammonia fueled swirl stabilized burner describing gas turbine nozzle. Starting from fundamental combustion test under designed nozzle fueled with methane and ammonia, energy ratio of ammonia could be reached about 80 % maintaining 20 kWth and M-flame to V-flame transition could be achieved having similarity to numerically conducted flame visualization. To predict, thermal performance and emission characteristics, 100 % of ammonia fueled condition was described with numerical approach based on validated model compared to test results. To optimize de-NO_x and NH₃ slip, in-situ SNCR effect could be achieved under axial multi-staging injection. In detail, NO_x reduction was confirmed by applying pulsed multi-staging injection and optimization of NO_x and NH₃ slip was conducted. The results showed that a sufficient oxidant concentration is required to induce efficient NO_x removal. Moreover, reaction pathway of NOx reduction mechanism was conducted based on detailed chemical reaction analysis.