| 摘要 |
PURPOSE:To supress generation of NOx in combustion to a low level by dividing the pulverized coal according to the size of its particles and burning it separately. CONSTITUTION:Pulverized coal enters a nozzle 1 as fluid mixture 4 mixed with primary air which serves also as the transferrer of the coal. The fluid mixture 4 flowing through the nozzle 1 toward a furnace 13 is imparted with a strong swirl while passing through a swirler 7. By this swirling, the coal particles of relatively large diameter are made to flow in the vicinity of the inner wall of the nozzle 1 under the centrifugal force, whereas the coal particles of relatively small diameter are made to flow in the central part, the latter is blown directly into the furnace 13 and burned. On the other hand, the large diameter coal particles flowing near the inner wall of the nozzle 1 is made to dash out of an opening 8 of the nozzle 1 under the centrifugal force into a secondary air nozzle 2, where it is mixed with secondary air and then blown into the furnace 13. Accordingly, referring to a drawing, the large diameter coal particles are distributed to a part I and the small diameter coal particles gather at a part II. In the part II, a great amount of volatile component produced can be burned at a low air- fuel ratio. In the partI, though the air-fuel ratio is high, the coal can be burned with a small amount of volatile component. Thus the generation of NOx can be supressed to a great extent. |
