Process and apparatus of combustion for reduction of nitrogen oxide emissions

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.

Description

[0001] This application claims priority to U.S. Provisional Application No. 60 / 348,661 filed Jan. 14, 2002, which is incorporated herein by reference in its entirety.[0002] The invention relates to a method and apparatus to reduce nitrogen oxide emissions from industrial combustion processes, and more particularly the invention relates to a method and apparatus to reduce nitrogen oxide emissions without affecting other emissions, such as carbon monoxide, by combining the technique of oscillating combustion with a system of post combustion removal of carbon monoxide.DESCRIPTION OF THE RELATED ART[0003] High-temperature, gas-fired furnaces, especially those fired with preheated air or industrial oxygen, produce significant quantities of nitrogen oxides (NOx) per unit of material processed. At the same time, regulations on emissions from industrial furnaces are becoming increasingly more stringent, especially in areas such as California.[0004] Operators have been looking for improved c...

AI Technical Summary

Problems solved by technology

Because of the competition, operators of such processes are thus facing a difficult challenge: to increase their productivity under the more and more stringent constraints of higher efficiency and reduced NOx emissions.

Low excess air reduces the available oxygen to the point which is just sufficient to oxidize the fuel but not so much as to cause emissions such as NOx and CO.

In terms of cost-effectiveness, the SCR and SNCR systems tend to have extremely high capital and maintenance costs.

However, with the new stringent emissions standards to be met, most of the NOx generating facilities are currently forced to use the most effective, but also the most expensive NOx reduction technology, namely SCR.

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