Combustion Method and System

Abstract

A method of combustion for pulverized hydro-carbonaceous fuel includes the steps of injecting an oxidant/fuel stream into a burner, causing a low-pressure zone; directing a flow of a high-temperature combustion gas from a combustion chamber into the low-pressure zone in the burner; mixing the high-temperature combustion gas with the injected oxidant/fuel stream to heat the injected oxidant/fuel stream, and injecting the heated oxidant/fuel stream from the burner to the combustion chamber, wherein the oxidant/fuel stream is rapidly devolatilized and combusted in a flame that has a high temperature; sensing a combustion parameter; and based on the sensed combustion parameter, controlling combustion to achieve at least one of a desired NOx reduction and a desired distance from the burner to a flame front.

Description

TECHNICAL FIELD OF THE INVENTION[0001]The present invention relates to a combustion method, and a combustion system, for solid hydrocarbonaceous fuel.BACKGROUND OF THE INVENTION[0002]Solid fossil fuel, such as coal, is an important energy source, particularly for power generation. Pollutants emitted from coal combustion, however, are a major source of air pollution. Of the pollutants from coal combustion, nitrogen oxides (NOx) have attracted extensive attention. There are two primary sources of NOx generated during combustion: fuel NOx and thermal NOx. Fuel NOx is NOx formed due to the conversion of chemically bound nitrogen (fuel nitrogen) during combustion. Fuel nitrogen (or char-N) is released in several complex combustion processes. The primary initial product of combustion is either HCN or NH3. HCN is then either oxidized to NO or reduced to N2. If the gases are oxidant or the fuel is lean, NO will be the dominant product of fuel nitrogen. If it is fuel rich, HCN is reduced to ...

AI Technical Summary

Benefits of technology

[0023]The combustion control of the present invention can be based on one or more combustion parameters. Representative parameters may be combustion temperature, pressure, and the concentration of one or more selected gases such as carbon dioxide, carbon monoxide, oxygen and nitrogen. Preferably, the temperature is used as the combustion parameter. The control may be realized by sensing the value of the combustion parameter inside the burner and/or the combustion chamber, and comparing the sensed value with a preset value.

Problems solved by technology

One of the problems is that although the prior art technologies for reducing NOx are based on solid theories, the devices based on the technologies often do not achieve optimum NOx reduction.

The reason is that those devices do not, or cannot quickly, adjust operating parameters to adapt to changing operating conditions for optimum NOx reduction.

For example, when the quality or type of coal changes or when the load is changed, the prior art devices do not, or cannot quickly, recognize the change and adjust the operating parameters to adapt to the change.

As a result, an optimum NOx reduction cannot be achieved for the coal being used.

Another problem associated with the prior art is that, in the case of the

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