Low-load stable combustion system and method for preheating pulverized coal

The invention relates to the technical field of coal-fired boiler power generation, and discloses a pulverized coal preheating low-load stable combustion system and method.Gas-solid separation is conducted on an air-powder mixture through a cyclone separator, primary air separated from the air-powder mixture is conveyed in two ways through a primary air duct, and one way of primary air is directly conveyed into a hearth of a boiler; one path of primary air is pressurized by a booster fan and then is introduced into an ejector, and the pulverized coal separated from an air-powder mixture is transferred into the ejector and enters a hearth of a boiler under the drainage action of the primary air pressurized by the booster fan, so that the combustion of the boiler is facilitated, and the combustion efficiency of the boiler is improved. Therefore, the pulverized coal dense-thin separation effect and the pulverized coal preheating effect of the primary air are remarkably enhanced, the pulverized coal is carried by