Control of nitrous oxide in boiler flue gases - by control of flow rate of recirculated flue gases to minimise formation of nitrous oxide before discharge into atmosphere

摘要

The boiler has a hearth (B) to support the fuel during combustion. A fan (A) recirculates flue gases to the front forced draught zone (a) and/or to the main air circulation zones (2,3,4) and/or to the rear forced draught zone (2). The flow of the flue gases to each of these zones as well as to the zone about the hearth is controlled in order to minimise the formation of nitrous oxides in the flue gases which are discharged to the atmosphere. The control of the flow rate is effected by valves fitted in the supply ducts (1 to 9). USE - Reduction of nitrous oxide in flue gases.