Pilot-scale evaluation of H2O2 injection to control to NOx emissions

Nitric oxide (NO) in combustion flue gasses can be converted to higher oxid ation states by the injection of aqueous solutions of hydrogen peroxide (H2 O2) into the hot flue gases. The NO is oxidized to NO2, HNO2, and HNO3, whi ch can then be removed in a wet scrubber. A pilot plant system that was des igned, constructed, and operated at Kennedy Space Center confirmed previous results that H2O2 is very effective at oxidizing NO; conversions of NO abo ve 90% were obtained at temperatures of about 500 degreesC (930 degreesF) u sing mole ratios of H2O2:NOx slightly above 1.0. The mole ratios of H2O2/NO x needed to obtain high conversions of NO were significantly lower in the p ilot plant that they had been in previous laboratory studies. demonstrating that this process can be an economically feasible method for NO, control. The position of the injector and the type of atomization were very importan t to the efficient utilization of peroxide. When SO2 was present in the flu e gas, both NO and SO2 were oxidized without increasing the demand for pero xide.