Nitrogen oxide emission reduction from burners - adds flue gas to combustion air for primary, sub-stoichiometric combustion zone

摘要

The process for reducing nitrogen oxide emission, when burning nitrogen containing fuels in an enclosed furnace, applies to combustion involving a sub-stoichiometric primary combustion zone and a super-stoichiometric secondary one. Primary air enters through the burners while secondary air has volume regulated according to the load. The secondary air is introduced around each burner, so as to form the primary zone boundary before feeding the second zone and entering the flame envelope. The air for the sub-stoichiometric phase has recirculated, partially cooled, flue gas admixed to it at a rate of up to 50% of the primary air flow.