Abstract: A combustion control system allows the dramatic reduction of NOx emission levels from industrial combustion processes without having recourse to expensive flue gas clean up methods. The system combines the technique of oscillating combustion with an adapted system for post combustion burn out of the excess of CO resulting from the low-NOx combustion zone. A process for fuel combustion includes generating an oscillating combustion zone by oscillating at least one of the fuel flow and the oxidant flow to achieve a reduced nitrogen oxide emission, selecting oscillating parameters and furnace operating parameters to maximize nitrogen oxide reduction efficiency to the detriment of carbon monoxide production, and combusting carbon monoxide downstream of the oscillating combustion zone by injecting a post combustion oxidant.

Abstract: This invention proposes innovative techniques of NOx reduction in boiler operation through an adaptation of staged combustion in combustion boilers. In preferred processes, air is fed into an air separation unit, and a nitrogen-enriched stream is combined with air to produce a nitrogen-enriched first stage air stream, and at least a portion of an oxygen-enriched stream is mixed with air to produce an oxygen-enriched second stage air stream. A reduction in NOx and increase in efficiency is promoted by the inventive processes and systems.

Abstract: Steam generation apparatus and methods are presented that are dedicated to oxygen-enriched air combustion of a fuel, wherein the oxygen concentration of the oxygen-enriched air may range from just above 21 percent to 100 percent. One apparatus comprises an oxygen-enriched air preheater through which oxygen-enriched air flows and exchanges heat indirectly with flue gas, creating a preheated oxygen-enriched air stream. The apparatus further comprises a boiler having a radiant section and a convection section, and other heat transfer units adapted to handle reduced flue gas flow rate and higher temperature flue gases than comparable air/fuel combustion boilers, thus allowing a smaller heat transfer surface area, a more compact design and a higher efficiency.

Abstract: This invention proposes innovative techniques of NOx reduction in boiler operation through an adaptation of staged combustion in combustion boilers. In preferred processes, air is fed into an air separation unit, and a nitrogen-enriched stream is combined with air to produce a nitrogen-enriched first stage air stream, and at least a portion of an oxygen-enriched stream is mixed with air to produce an oxygen-enriched second stage air stream. A reduction in NOx and increase in efficiency is promoted by the inventive processes and systems.