Combustion boiler and combustion method using oxyfuel reburn burners

摘要

A method and apparatus for reducing NO x emissions in a coal burning furnace of a power plant without utilizing techniques downstream of the furnace, such as SCR and SNCR, is provided. In a primary combustion zone, a fuel is combusted in the presence of a first oxidant gas comprised substantially of N 2 , to produce a first effluent gas that include one or more NO x species. Downstream a re-burn zone is operated in a sub-stoichiometric manner, combusting a second fuel in presence of the first effluent gas and a second oxidant wherein the second oxidant gas comprises a stream of oxygen. The effluent gas from the re-burn zone is introduced to overfire airflow so as to establish a super-stoichiometric zone prior to discharged from the furnace.