System And Method For Controlling And Reducing Nox Emissions (General Electric Company)

CATEGORY: NOx CONTROL
PATENT
System And Method For Controlling And Reducing Nox Emissions (General Electric Company)
United States Patent Application 20130098049
Inventors:
Kraemer, Gilbert Otto (Greer, SC, US)
Acharya, Harish Radhakrishna (Clifton Park, NY, US)
Thatcher, Robert Thomas (Greer, SC, US)
Application Number:
13/279186
Publication Date:
04/25/2013
Assignee:
General Electric Company (Schenectady, NY, US)
Abstract:
A system includes a gas production source configured to produce a gas stream comprising nitrogen oxides (NOx) and a hydrocarbon injector disposed downstream of the gas production source and configured to inject a hydrocarbon into the gas stream. The hydrocarbon is configured to oxidize molecules of the NOx in the gas stream to produce a higher order compound of nitrogen and oxygen (NyOz). The system also includes a removal device disposed downstream of the hydrocarbon injector. The removal device is configured to remove the NyOz from the gas stream via absorption or reaction.
BACKGROUND OF THE INVENTION
The subject matter disclosed herein relates to reducing emissions of nitrogen oxides (NOx), and more particularly, to systems and methods for reducing NOx emissions from NOx producing sources.
NOx emissions are a concern for many industries, particularly in power-generating industries. NOx production may occur in high-temperature combustion applications and/or with the combustion of nitrogen-bearing fuels. At high combustion temperatures, diatomic nitrogen in the combustion air may be oxidized to produce NOx. Nitrogen in the fuel may also be released as free radicals during combustion to form NOx. One approach to NOx reduction involves the injection of a reducing agent over a catalyst to convert NOx to N2. For example, ammonia may be used with a selective catalytic reduction (SCR) catalyst to reduce NOx emissions. However, such methods may generate particulates that foul downstream equipment, thereby increasing maintenance and cleanup costs.
BRIEF DESCRIPTION OF THE INVENTION
Certain embodiments commensurate in scope with the originally claimed invention are summarized below. These embodiments are not intended to limit the scope of the claimed invention, but rather these embodiments are intended only to provide a brief summary of possible forms of the invention. Indeed, the invention may encompass a variety of forms that may be similar to or different from the embodiments set forth below.
In a first embodiment, a system includes a gas production source configured to produce a gas stream comprising nitrogen oxides (NOx) and a hydrocarbon injector disposed downstream of the gas production source and configured to inject a hydrocarbon into the gas stream. The hydrocarbon is configured to oxidize molecules of the NOx in the gas stream to produce a higher order compound of nitrogen and oxygen (NyOz). The system also includes a removal device disposed downstream of the hydrocarbon injector. The removal device is configured to remove the NyOz from the gas stream via absorption or reaction.
In a second embodiment, a system includes a hydrocarbon supply system configured to supply a hydrocarbon into a gas stream. The hydrocarbon is configured to oxidize nitrogen oxides (NOx) in the gas stream to produce a higher order compound of nitrogen and oxygen (NyOz). The system also includes a removal device disposed downstream of the hydrocarbon supply system. The removal device is configured to remove the NyOz from the gas stream via absorption or reaction. The system also includes a controller configured to adjust the hydrocarbon injector and/or the removal device in response to sensor feedback to reduce a NOx level below a threshold NOx level in the gas stream downstream of the removal device.
In a third embodiment, a method includes oxidizing nitrogen oxides (NOx) in a gas stream by contacting the gas stream with a hydrocarbon to produce a higher order compound of nitrogen and oxygen (NyOz) and removing the NyOz from the gas stream via absorption or reaction downstream from the oxidizing.
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