What can be done to reduce NOx emissions on a gas turbine?
A prime area where NOx emissions can be reduced is in the combustor. Newer gas turbines employ dry low NOx (DLN) combustion technology to achieve high single digit NOx emissions. With DLN technology, the air and fuel are premixed in order to atomize the fuel in the air to allow combustion at a lower temperature. In older diffusion flame technology, the fuel and air are kept apart until combustion occurs. Even with DLN technology, gas turbines require additional NOx abatement equipment in order to reach the 5 ppm and lower NOx emissions levels required in some parts of the country. For mature frame gas turbines, there are some combustion upgrades available to reduce NOx emissions. While some frames have a DLN combustion retrofit available, most are retrofit with a water or steam injection system. Water and steam injection systems reduce the flame temperature in the combustor and thus hinder the formation of thermal NOx. In addition to contributing to an increase in output, these types o
