METHOD FOR REDUCTION OF SLAGGING AND FOULING OF THE WATERWALLS AND OF THE FIREBOX AND SUPERHEATER AND REHEATER OF STEAM BOILERS WITH COAL COMBUSTION

摘要

The present invention is a method for reducing the slagging and fouling of the surfaces of the waterwalls, firebox, superheater, and reheater of the furnace of a coal-fired steam boiler. The process reduces the firebox exit temperature to below the specific ash melting temperature by injecting the following, either alone or in combination, into ports located in the upper section of the firebox: recirculated flue gas from downstream of the electrostatic precipitator, atomized water, or a sorbent water slurry. All of these materials have a lower temperature than the main flue gas or require additional heat for evaporation. Mixing these materials with the main flue gas from the furnace will not affect the coal combustion process, yet will reduce the temperature of any fly ash particles in the main flue gas to below the specific ash fusion temperature, and thus, prevent slagging and fouling within the furnace.