Catalyst durability evaluation for advanced gas turbine engines

Catalytic combustion has demonstrated the ability to provide low NO(x) emissions while maintaining high combustion efficiency. Recently, under joint NASA Lewis, EPA, and Acurex sponsorship, a catalytic reactor was tested for 1000 hours to demonstrate durability in combustion environments representative of advanced automotive gas turbine engines. At a 740K air preheat temperature and a propane fuel/air ratio of 0.028 by mass, the adiabatic flame temperature was held at about 1700K. The graded cell monolithic reactor measured 5 cm in diameter by 10.2 cm in length and was operated at a reference velocity of 13.4 m/s at 1 atmosphere pressure. Measured NO(x) levels remained below 5 ppm while unburned hydrocarbon concentrations registered near zero and carbon monoxide levels were nominally below 20 ppm. The durability test included several parametric turndown studies and ended with a series of on/off cycling tests to further characterize reactor performance.