Evaluation of the nitrogen oxide emission level for a steam supply with natural gas into the combustion chamber of a gas turbine unit

Numerical simulation results on the effect of the operation parameters for a combustion chamber of a combined-cycle plant (CCP) with steam injection [1] for the combined production of heat and electric energy upon a reduction in nitrogen oxide emission are represented. Calculations are carried out for lean mixtures with alpha = 1.2-1.4 and great steam consumptions of 30-42%. The reaction analysis has shown that the main contribution in NO (x) formation was given by reactions with the advanced Zel'dovich thermal mechanism, and the reaction contribution with the participation of N2O into the NO formation was an order of magnitude higher than that by the mechanism of the prompt NO formation. NO2 does not form at high temperatures and only takes part in the conversion into NO in reactions with the participation of nitric acid. It is shown that the optimum choice of operation conditions for the combustion chamber of the CCP makes it possible to obtain the NO (x) content in the combustion products in some mill(-1) (ppm). According to calculations, steam injection does not increase CO emission. A comparison with the experiment is given.