Research on Nox Formation and SCR Denitration System Control by Smoke Mixing Under Low Load

With 2 x 330MW subcritical coal-fired boiler as the research object, the influence of two kinds of primary air flue gas recirculation schemes on the combustion of pulverized coal and the formation of NOX were studied by numerical simulation software. The variation law of SCR inlet fume temperature was studied with boiler thermodynamic calculation. The calculation results show that the reasonable smoke mixing method can effectively improve the SCR inlet flue gas temperature and reduce the furnace outlet NOX concentration. The optimal proportion was 20% with the primary air mixing smoke while maintaining constant air mass. The results of numerical simulation and thermodynamic calculation show that SCR inlet flue temperature can be increased by 15 degrees C, the concentration of NOx emission can reduce by 18.29mg/Nm(3).