Boiler with fine gas return flow - has temperature sensor to control cooling air flow to limit flue gas temperature

摘要

A boiler, which is fired with pulverised coal, can divert some of the flue gases (3) for mixing with combustion air. The flue gases flow through the duct (42) to return to the air inlet of the boiler combustion chamber. To prevent overheating of the outlet from the pulverising mill, a temperature sensor (6) is fitted in the wall of the flue gas duct (42). This temperature sensor controls an actuator (22) which in turn controls the flow of cold air through the ducts (8) and (15) and thus controls the temperature of the flue gases in the duct (42). USE/ADVANTAGE - Control of return flow flue gas temperature and at the same time control of the temperature of the combustion air.