Method of reducing NOx emission from multi-zone reheat furnaces

摘要

A method for controlling NOx in a multi-zone re-heating furnace used for meeting process heating (or re-heating) requirements in the metals industry. Oxidant-fuel stoichiometry is altered in different zones of a multi-zone re-heating furnace to reduce the overall NOx emission without replacing existing burners or intrusively modifying the furnace (or drilling holes in the furnace) for fuel and/or an oxidant injection. The oxidant-fuel stoichiometry in at least one zone of a multi-zone re-heating furnace is made either oxidant neutral or oxidant deficient (or fuel rich) to reduce the formation of NOx and the oxidant-fuel stoichiometry of at least one other zone that is located downstream of the oxidant neutral or oxidant deficient zone is made oxidant rich (or fuel lean) to further reduce the formation of NOx in the furnace.