I work with Siemens V94.2 Gas Turbines at a combined cycle gas turbine power station, they control the NOx levels by using a hybrid gas burners. The GT starts up in diffusion burner mode for a stable flame (this flame has hots spots leading to high NOx levels, Once above a certain gas outlet temp the burners change to Pre-mix burner mode ( mixing the air with the gas at the burner), this flame has a much more even temperature but does require a pilot gas supply due to the flame in-stability. In pre-mix mode the NOx levels are greatly reduced.<br>
On some machine they inject steam into the exhaust to reduce NOx.<br>
Smit
