Method and device for determining opposite firing air supply quantity and automatic control system

The invention provides a method and a device for determining opposite firing air supply quantity and an automatic control system, and belongs to the technical field of burner operation air quantity control. The method comprises the following steps: determining opposite firing operation oxygen quantity, primary burning area excess air coefficient and burnout air quantity distribution coefficient of each layer of burnout air bellow; and determining the opposite firing air supply quantity according to the total fuel quantity fed by furnace walls where the burnout air bellows are located, the analysis data of preboiler coal grade, as well as the opposite firing operation oxygen quantity, the primary burning area excess air coefficient and the burnout air quantity distribution coefficients. The opposite firing air supply quantity is determined through the total fuel quantity fed by the furnace walls where the burnout air bellows are located, the analysis data of preboiler coal grade, as well as the opposite firing operation oxygen quantity, the primary burning area excess air coefficient and the burnout air quantity distribution coefficients, so that the air supply quantity in the low-NOx opposite firing process is automatically controlled in the boiler operation process, and low-level NOx concentration at a furnace outlet can also be maintained while high efficient combustion is guaranteed.