Abstract: The reasons of higher NOx concentration emission of two 670t/h pulverized coal fired boilers in Shengli Power Generation Plant of Shengli Petroleum Administration of phase 1 were analyzed. The process of dramatic reducing NOx concentration by optimizing combustion was introduced. After jet burner changing to "horizontal bias air combustion pulverized coal burner", and then staging air and staging powder transfer to optimize combustion, the decreasing amplitude of concentration NOx emission reached to 40%, the obviously effect in reducing boiler NOx emission was gained.

Key words: coal-fired boiler, optimizing combustion, horizontal bias air combustion pulverized coal burner, nitrogen oxide