| 摘要 |
PROBLEM TO BE SOLVED: To lower NOx without largely improving an existing boiler by providing a high cycle regenerative combustion burner in a furnace of the boiler, and recirculating part of boiler exhaust gas exhausted from a heat transfer part adjacent to the furnace to the furnace. SOLUTION: The boiler 1 comprises a feed water preheater 3, an evaporator 4 and a superheater 5 in a heat transfer part 2. A furnace 8 disposed at a lower part of the transfer part 2 has a high cycle regenerative combustion burner 20. In the boiler 1, a branch tube 11 branched from a discharge tube 10 connected to its outlet 9 is connected to a bottom of the furnace 8, and part of boiler exhaust gas G" is supplied into the furnace 8 by a circulation fan 12 provided on the way of the tube 11. Recirculation gas (low-oxygen atmosphere gas) G' supplied from the tube 11 into the furnace 8 is entrained in this burner flame to suppress generation of NOx generated by the burner. |
