초록 ▼

A low-NOx boiler comprises a burner for burning gaseous fuel, heat transfer pipes heating water by combustion heat of the burner to generate steam and having a passage through which water flows, a steam drum communicating with the heat transfer pipe and accumulating the steam from the heat transfer

A low-NOx boiler comprises a burner for burning gaseous fuel, heat transfer pipes heating water by combustion heat of the burner to generate steam and having a passage through which water flows, a steam drum communicating with the heat transfer pipe and accumulating the steam from the heat transfer pipe, and an exhaust gas duct located in the furnace to exhaust combustion gas generated by combustion of gaseous fuel outside of the boiler. The boiler further comprises unburnt gas burner in the exhaust gas duct for burning unburnt content in the combustion gas flowing in the duct. The unburnt gas burner includes a nozzle for injecting premixture flow of fuel and combustion air and flame holding plate located near the downstream side of the outlet of the nozzle to interrupt the premixture flow to form a circulating flow on downstream side of the flame holding plate. As gaseous fuel and air are mixed in advance and a flame is formed, the flame length can be shortened. Furthermore, the flame holding plate enables to reduce NOx generated. Unburnt gas burner provided in the exhaust gas duct makes it possible to notably reduce the concentration of NOx discharged to the outside of the system.

대표청구항 ▼

A low-NOx boiler comprising: a furnace; a burner provided in said furnace for burning gaseous fuel, said burner having nozzle means for injecting a premixture of gaseous fuel and combustion air, and flame holding means located near a downstream side of said nozzle means to interrupt a flow of said p

A low-NOx boiler comprising: a furnace; a burner provided in said furnace for burning gaseous fuel, said burner having nozzle means for injecting a premixture of gaseous fuel and combustion air, and flame holding means located near a downstream side of said nozzle means to interrupt a flow of said premixture to form a circulating flow on a downstream side of said flame holding thereby forming swirls of combustion gas inside and outside of a premixture flame; heat transfer pipe means for heating water by combustion heat of said burner to generate steam, said heat transfer pipe means being located in said furnace and having a passage through which water flows; the steam drum means communicating with said heat transfer pipe means and accumulating therein said steam from said heat transfer pipe means; exhaust gas duct means located in said furnace for exhausting combustion gas generated by combustion of the gaseous fuel outside of said boiler; and uncombusted gas combusting means located in said exhaust gas duct for combusting an uncombusted content in said combustion gas flowing in said exhaust gas duct means.