Study on the technology of SCR flue gas temperature adjustment during low load in coal-fired boilers

With more and more power plants participating in the low load peaking operation of the power grid, the problem that flue gas temperature at the inlet of the SCR reactor is close to or cannot meet the minimum allowable requirements of the catalyst has become the general focus. This paper summed up advantages and disadvantages of system modification methods that are used to improve the inlet smoke temperature of SCR reactor. It discussed the methods to improve the inlet smoke temperature of SCR reactor through combustion adjustment at low load operation, and proved the adjustment effect of these methods by experiment. Research shows that, methods to improve inlet smoke temperature of the SCR reactor focused on system transformation, but the cost was high. This paper increased the rate of SCR usage by the combustion adjustment. That not only eliminated the time cost, investment cost and maintenance cost of the system transformation, but also made it not difficult to control the system and had less impact on the efficiency of the boiler. The results of this paper provide theoretical basis and technical support for the adjustment direction of similar units.