Nitrogen oxide concentration control system in low-load circulating fluidized bed boiler

The utility model relates to a nitrogen oxide concentration control system in a low-load circulating fluidized bed boiler. The nitrogen oxide concentration control system comprises a flue gas analyzer, a PID controller and a flow control valve, a hearth of the circulating fluidized bed is connected with the cyclone separator through a smoke exhaust pipe, a carbon monoxide inlet pipe is arranged on the side, close to the hearth, of the smoke exhaust pipe, and a catalytic reduction reaction device is arranged in the middle of the smoke exhaust pipe. The flue gas analyzer monitors the concentration of carbon monoxide and the concentration of nitrogen oxide near the gas inlet end of the smoke exhaust pipe in real time and sends the measured data to the PID controller; a flow control valve is arranged on the carbon monoxide inlet pipe, and the PID controller controls the opening degree of the flow control valve according to the real-time carbon monoxide concentration and nitrogen oxide concentration. According to