Operating method for boiler combustion system - using gas from air preheater outlet, reheated before return to combustion air system

摘要

The method for operating a combustion system, partic. of a steam generator with combustion-gas air preheater, is for layouts where part of the gas is recirculated after the heater. It applies esp. to lignite fired plant. After electrostatic filtration the gas is re-cycled through a separate part of the preheater, using a recirculating blower, before being fed into the fuel pickup duct. There it mixes with hot gas from the furnace. Fuel and gas then flow via the pulveriser to the burners. With liquid or gaseous fuel, the gas is recycled direct to the burners.