Gas turbine engine test of RCL® catalytic pilot for ultra-low NOx applications

Catalytic combustion offers improved combustion stability extending the lean flame temperature limit to allow ultra-low NOx emissions. Instead of replacing the entire lean-premixed (LP) injector with a catalytic injector, advanced Rich Catalytic/Lean-burn (RCL®) technology is developed and integrated to replace only the pilot portion of the injector. The pre-reaction within the pilot provides enhanced reactivity reducing the need to use higher temperature flames to stabilize the combustor primary zone. This concept synergistically combines the best features of catalytic combustion and conventional aerodynamically stabilized combustion technology.The present paper discusses the development and engine testing of a set of Taurus 70 injectors equipped with RCL® pilots for natural gas applications. Testing showed engine NOx emissions of ∼2.5 ppmv corrected to 15% O2 were achieved at baseload conditions. Engine CO emissions were less than 2 ppm. Combustor acoustics were low (at or below 0.1 psi RMS) during testing. The RCL® catalytic pilot supported the engine startup and shutdown process without major modification of existing engine controls. These initial results are promising. Further development work is needed to establish long term catalyst durability, engine transient behavior, and advancing the pilot technology to production status.