Advanced control system for enhanced operation of oscillating combustion in combustors

Abstract

Methods for optimizing emission levels from combustion operations, which include a system and process for optimizing levels of NOx and CO during fuel combustion including supplying flows of fuel (which is predetermined) and main oxidant to a burner. Oscillating combustion is generated by oscillating the fuel flow with an oscillating valve and combusting the oscillating fuel with the main oxidant adjacent the burner to produce combustion products. A post-combustion oxidant is injected into the combustion products where it is combusted with the combustion products. A controller is operatively associated with control units for controlling the main oxidant and post-combustion oxidant flow rates and the oscillating valve.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims benefit under 35 U.S.C. § 119(e) to provisional application No. 60 / 635,737, filed Dec. 13, 2004, the entire contents of which are incorporated herein by reference.RELATED ART [0002] The concept of oscillating combustion is a recognized technology for the reduction of NOx in industrial furnaces. The principle and the various methods of implementation are broadly described in U.S. Pat. No. 4,846,665, U.S. Pat. No. 5,302,111, and U.S. Pat. No. 5,522,721. The main idea is to pulse the flow of fuel, or air being supplied to at least one burner of the furnace, to generate successive fuel-rich and fuel-lean zones in a flame; thereby, reducing NOx emissions. [0003] The inventors are only aware of oscillating combustion's commercial implementation in large multi-fired industrial furnaces, such as glass and steel reheating furnaces. In these processes, integration of oscillating combustion to the furnace is relatively easy...

AI Technical Summary

Benefits of technology

[0007] A process for optimizing levels of NOx and CO during fuel combustion is performed and includes the steps of a flow of a fuel to a burner is supplied, and flow of a main oxidant is supplied to a burner. The flow rate of the main oxidant is controlled by a main oxidant flow rate control unit. Oscillating combustion is generated by oscillating the fuel flow with an oscillating valve and combusting the oscillating fuel with the main oxidant adjacent the burner to produce combustion products. A post-combustion oxidant is injected into the combustion products. The injection rate of the post-combustion oxidant injection being is controlled by a post-combustion oxidant flow rate control unit. The combustion products and the injected post-combustion oxid

Problems solved by technology

In most cases, these proposed processes are running at varying loads without human / operator intervention, and are subject to frequent shut-downs and start-ups.

This complicates the operation on top of controlling the additional oxidant flow.

Many problems arise from the implementation of the oscillating combustion technology in these types of processes.

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