Reduction of nitric oxide from combustion flue gas by bituminous coal char in the presence of oxygen

A detailed parametric study quantifying the effect of various operating parameters on the reduction of nitric oxide (NO) in the presence of oxygen by inexpensive carbons was carried out. The selectivity of the carbon-NO reaction over the parasitic carbon-oxygen reaction was measured by a global selectivity parameter, defined as milligrams of NO reduced per gram of carbon consumed. An increase in the reaction temperature, bed height, and inlet NO concentration leads to a higher selectivity factor. However, there exists an optimum particle size of carbon that maximizes this selectivity. Whereas, in the absence of oxygen, the rate of the carbon-NO reaction was insignificant, the presence of oxygen in the inlet creates active sites that convert NO to nitrogen. An optimum inlet oxygen concentration provided the highest degree of NO reduction. The operating conditions can be selected to achieve >90% NO reduction at a selectivity of 60-100 mg of NO reduced/g of carbon.