Firing equipment for pulverised fuel, such as lignite - using water injection into recirculating gas and combustion zone turbulence increased by steam nozzles

摘要

The firing equipment for pulverised fuel, partic. lignite, comprises burners (2) firing into the combustion chamber (1) and water nozzles (8) spraying into the entry of a duct (3) recirculating gas from the furnace exit (4). This water is preheated to about 90 deg.C, for rapid evaporation. The recirculated mixture is drawn into the pulveriser (6) where fuel from a feedline (5) is added and the whole discharged (7) to the burners. Additional nozzles (9) in between the burners allow steam to be injected into the combustion zone. Variation of the total amount/proportions of water from these two sources, permits limitation of the combustion chamber exit temp. to below the ash-softening figure, minimising gas path fouling. Combustion zone turbulence is also increased by the steam from the lower nozzles.