Experimental Study of NO Removal by Gas Reburning and Selective Noncatalytic Reduction using Ammonia in a Lab-Scale Reactor

An experimental investigation has been performed to study the efficiency of NO reduction by three technological approaches: reburning by methane, selective noncatalytic reduction (SNCR) by ammonia, and a hybrid approach by coupling reburning and SNCR. Experiments were performed on a lab-scale reactor equipped with a McKenna flat flame burner able to generate the flue gas with well-known features. The desired levels of initial NO were achieved by seeding the flame with known amounts of nitric oxide. Experiments were performed throughout the temperature range of interest, i.e., from 973 to 1213 K, to investigate the effects of main working parameters on the performance of the NO reduction process. As a result, very high efficiencies of NO reduction have been obtained using, respectively, methane (up to 90%) and ammonia (up to 75%) as a reducing agent. When these two processes are coupled in a reburn/SNCR hybrid technique, higher efficiencies in NO reduction have been obtained by a comparison to the classical SNCR technique. The computational fluid dynamic (CFD) modeling has also been investigated to characterize the fluid dynamics in the reactor, notably the gas homogeneity. Furthermore, the modeling results obtained with the commercial CFD code FLUENT 6.3 showed a good agreement with measurements.