Patent ID: 8656846

Claim:
An apparatus for adjusting the air/fuel ratio of a burner for the boiler of a coal-firing system based on coal quality information, said apparatus comprising: a dual-energy/multi-energy gamma attenuation device positioned to obtain an energy spectrum for coal passing from the output of a coal bunker in the coal-firing system and the input of a coal feeder in the coal-firing system; and a processor receiving data from said dual-energy/multi-energy gamma attenuation device, said processor adapted to communicate with the controls for the coal feeder, said processor executing a program for adjusting the air/fuel ratio comprising the steps of: determining coal quality information of the coal based on said energy spectrum; determining the first delay value representing the amount of time required for the coal to be conveyed from the coal bunker to a pulverizer in the coal firing system by the coal feeder based on the current velocity of a conveyance included in the coal feeder; determining a second delay value representing the amount of time required for the coal to be pulverized and the coal to be carried from the pulverizer to the burner of the coal firing system based on the velocity of a primary air supply flowing from the pulverizer to the burner; selecting an air/fuel ratio of air to pulverized coal supplied to the burner for controlling the stoichiometry of the burner based on said coal quality information of the coal; calculating an air supply rate and a coal supply rate required to produce the selected air/fuel ratio at the burner based on the energy content derived from said coal quality information of the coal; selecting a velocity for the conveyance to supply coal at the calculated coal supply rate; and adjusting the velocity of the conveyance to the selected velocity and air supply rate after a time delay equal to the sum of said first delay value and said second delay value, causing the air/fuel ratio of the burner to be adjusted contemporaneously with the arrival of the coal on which the air/fuel ratio is based whereby the burner stoichiometry is controlled.