PURPOSE: To reduce nitrogen oxide and/or unburnt constituents in the exhaust gas of combustion in a boiler device for thermal power plant industry or the like.
CONSTITUTION: Main burners 103 are provided at the upper part of a boiler furnace 101 and combustion gas discharging port 130 is provided at the lower part of the same while additional air throwing nozzles 106 are provided at the middle part of the same respectively to burn fuel downwardly. A buoyancy is generated in a direction reverse to the flow of combustion gas 124 and, therefore, the stagnating time of the combustion gas in either a reducing area 121 or an oxidizing area 122 is elongated and the reduction of nitrogen oxide as well as the combustion of unburnt constituents are effected sufficiently whereby respective amounts of both of them are reduced.
TOKUDA KIMIYO
OGURI MASAHARU
CHORYO ENG