| 摘要 |
PURPOSE:To reduce the nitrogen oxide contents of exhaust gas by a method wherein the amount of air supply is controlled so that the air ratio of a lower stage main burner becomes 1.0 or less, the air ratio of an upper stage main burner becomes 0.4-0.8 and the accumulating air ratio of the upper stage main burner, lower stage main burner and lower stage sub burner becomes 1.0 or less while the air ratio of the upper stage sub burner is varied from 0.3 to 0.8. CONSTITUTION:The lower stage main burner 1a, the lower stage sub burner 2a, the upper stage main burner 1b and the upper stage sub burner 26 are arranged sequentially from the bottom of the furnace 7 or sequentially from the upstream side of flow of exhaust gas while an after air port 3 is arranged at the lowest downstream portion. The amount of the air supply is controlled so that the air ratio of the lower stage main burner 1a becomes 1.0 or less, the air ratio of the lower stage sub burner 2a becomes 0.4-0.8 and the accumulating air ratio between the upper main burner 1b and the lower sub burner 2b becomes 1.0 or less while the air ratio of the upper stage sub burner 2b is varied from 0.3 to 0.8. According to this method, the nitrogen oxide contents of the exhaust gas may be reduced. |
