Middle powder bin combustion powder feeding system for low-load stable combustion of boiler

An intermediate powder bin combustion powder feeding system for low-load stable combustion of a boiler comprises a coal mill, a powder feeding unit and a hearth. The pulverized coal feeding unit comprises a first mill outlet pulverized coal pipeline insertion plate door, a gas-powder separator, a gas lock, a connecting pulverized coal bunker, a pulverized coal insertion plate door, a pulverized coal feeder and a mixer, an outlet of the coal mill is not less than two channels, the bottom of the pulverized coal bunker is provided with not less than two channels which are respectively connected to pulverized coal burners in the hearth, and the pulverized coal burners are connected with the gas-powder separator and the gas lock. The number of the pulverized coal burners is the same as that of channels arranged at the bottom of the pulverized coal bunker, the outlet end of the pulverized coal mixer is connected with the burner inlet pulverized coal pipeline inserting plate door through a pipeline, the burner inlet