| 摘要 |
<p>PURPOSE:To reduce production of nitrogen oxide without an increase in smoke dust in exhaust gas by a method wherein a device is constituted such that an amount of recycle exhaust gas is varied at each or each group of burners mounted in multistage in a furnace. CONSTITUTION:Exhaust gas 2, generated in a furnace 1, is exhausted as discharged gas 3 to the open air, and after recycle gas, produced as a result of extraction of a part of the exhaust gas 2, flows through a line 4 and is adjusted in a flow rate at a recycle inlet damper 5, the gas is boosted by a recycle fan 6, and a part thereof is fed to a furnace 1 from a hopper inlet damper 7 through a hopper port 8. The recycle gas is used mainly for control of a steam temperature in a boiler. After the flow rate of the remaining recycle gas is regulated by means of a gas mixing inlet damper 8, the gas is further boosted with the aid of a gas mixing fan 10, and is fed to each of a feed line for primary and secondary air feed systems I and II and a feed line for a tertiary air feed system III. This enables independent variation of the flow rate of the recycle gas, fed to the primary and secondary air side, and the tertiary air side of the burner of their respective stage burners, through regulation of gas dampers 13, 14, 15, 16, 17, and 18 corresponding to their respective stages burners.</p> |
