Patent ID: 8601957

Claim:
A device for controlling, a fuel-air-ratio during combustion of ground coal in a firing system of a coal-fired power plant, comprising pneumatic transporting of the ground coal to a burners of the coal-fixed power plant, a feeder for feeding combustion air to the burners ( 13 ) or a combustion chamber ( 12 ) of the firing system of the coal-fired power plant, a fresh air blower ( 3 ) for suctioning fresh air from the atmosphere, a mill blower ( 4 ) for transporting a portion or the suctioned fresh air as carrier air for loading with ground coal, a regenerative air pre-heater ( 5 ) for preheating the suctioned fresh air and a portion of the carrier air by using the flue-gas heat from the firing system of the coal-fired power plant, wherein a storage mass of the regenerative air pre-heater ( 5 ) is alternatingly heated by the hot flue gas and subsequently cooled by the fresh air or by a portion of the carrier air, an air quantity control device for controlling the quantity of combustion air to be used for the pneumatic transport of the ground coal, and measurement devices ( 10 , 17 , 18 ) for measuring the quantity of combustion air introduced into the combustion chamber ( 12 ) and of the quantity of carrier air to be used for pneumatic transport of the ground coal, and of device ( 8 , 11 ) for metered feed of a preselected quantity of ground coal to the burners ( 13 ), the fresh air blower, the mill blower, the regenerative air pre-heater, the air quantity control device are arranged in the flow direction of the air, and wherein, for measuring the combustion air ( 17 , 18 ) a correlation measurement device is provided which evaluates triboelectric effects at two sensors disposed in the combustion air flow and sequentially arranged in the flow direction of the combustion air, and wherein the sensors are arranged in the channel system carrying the combustion air after the regenerative air pre-heater ( 5 ) in the flow direction of the combustion air and that at least one device ( 2 ) for metered introduction of fine-grained particles into the air flow is disposed before the sensors of the correlation measurement device in the flow direction of the combustion air.