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US 11,027,237 B2Granted
Direct injection of aqueous urea
AssigneeAmerican Electric Power Company, Inc.
InventorsDarren C Hanby, Jeffery L Hofacre
Life of this patent
Estimating the term…
Abstract
This disclosure provides an apparatus and method for reducing emissions of nitrogen oxides (NOx) from a combustion source. For example, a method and apparatus for injecting a urea solution directly into the flue gas stream of a coal-fired power plant that utilizes Selective Catalytic Reduction (SCR) to lower NOx emissions.
Claims15
A method for reducing the concentration of at least one predetermined chemical constituent comprising:
- selecting the at least one predetermined chemical constituent for removal from an exhaust gas stream produced by combustion of a solid fuel and having a thermal energy component and a pressure;
- passing the exhaust gas stream through a first turbulence producing device so as to distribute the predetermined chemical constituent throughout the exhaust gas stream,
- injecting into the exhaust gas stream, at an injection location and via at least one atomizing nozzle proximate to a second turbulence producing device, at least one reagent having a temperature and a pressure selected to facilitate the removal of the at least one predetermined chemical constituent;
- converting the at least one reagent to a first reaction by-product, utilizing substantially only the thermal energy present in the exhaust gas stream;
- passing the exhaust gas stream through the second turbulence producing device so as to distribute the first reaction by-product and the predetermined chemical constituent substantially uniformly throughout the exhaust gas stream;
- reacting the at least one predetermined chemical constituent with the first reaction by-product, converting the predetermined chemical constituent to a second reaction by-product, thereby reducing the concentration of the chemical constituent in the exhaust gas stream;
- and
- reacting the at least one predetermined chemical constituent and the first reaction by-product in the presence of a catalyst downstream of the injection location and first and second turbulence producing devices, whereby the catalyst acts upon the at least one predetermined chemical constituent and the first reaction by-product, converting substantially all of the at least one predetermined chemical constituent into the second reaction by-product.
5 more elements
An apparatus for reducing the concentration of at least one redetermined chemical constituent comprising:
- a solid fuel combustion unit further comprising a furnace;
- a first turbulence producing device downstream of the furnace and configured to distribute the at least one predetermined chemical constituent substantially homogenously throughout a gas stream produced by the solid fuel combustion unit;
- at least one atomizing nozzle to inject a reagent at an injection location into the gas stream;
- a second turbulence producing device in proximity to the at least one atomizing nozzle, wherein the second turbulence producing device is configured to distribute a first reaction by-product and the predetermined chemical constituent substantially uniformly throughout the gas stream;
- and
- a catalytic reduction module downstream of the injection location and first and second turbulence producing devices to act upon the at least one predetermined chemical constituent and the first reaction by-product to convert substantially all of the at least one predetermined chemical constituent into a second reaction by-product.
3 more elements
A method for reducing the concentration of at least one predetermined chemical constituent which comprises the steps of:
- generating a gas stream utilizing a solid fuel combustion unit wherein the gas stream comprises a thermal energy component, a pressure component, and the at least one predetermined chemical constituent;
- selecting at least one reagent having a temperature and a pressure, such reagent selected to facilitate the removal of the at least one predetermined chemical constituent from the gas stream;
- passing the gas stream through a first turbulence producing device so as to distribute the predetermined chemical constituent throughout the gas stream,
- injecting into the gas stream, at an injection location and via at least one atomizing nozzle proximate to a second turbulence producing device, the at least one reagent selected to facilitate the removal of the at least one predetermined chemical constituent;
- converting the at least one reagent to a first reaction by-product, utilizing substantially only the thermal energy present in the gas stream;
- passing the gas stream through the second turbulence producing device so as to distribute the first reaction by-product and the predetermined chemical constituent substantially uniformly throughout the gas stream;
- reacting the at least one predetermined chemical constituent with the first reaction by-product, converting the predetermined chemical constituent to a second reaction by-product, thereby reducing the concentration of the chemical constituent in the exhaust gas stream;
- and
- reacting the at least one predetermined chemical constituent and the first reaction by-product in the presence of a catalyst downstream of the injection location and first and second turbulence producing devices, the catalyst acting upon the at least one predetermined chemical constituent and the first reaction by-product, converting substantially all of the at least one predetermined chemical constituent into a second reaction by-product.
6 more elements
Dependencies are inferred from the claim text.