Catalytic Devices for Converting Urea to Ammonia
First Claim
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1. An apparatus for treating exhaust comprising:
- (a) a housing having an upstream inlet for receiving the exhaust, and a downstream outlet for discharging the exhaust, the housing defining an axial flow path for the exhaust;
(b) an injector configured to inject a urea solution into the exhaust;
(c) a permeable catalytic device for converting urea to ammonia positioned in the axial flow path downstream of the injector, wherein the catalytic device has an upstream face that is positioned at an angle of about 20-70 degrees relative to the axial flow path and the catalytic device is configured to receive the urea solution from the injector at the upstream face; and
(d) a selective catalytic reactor for converting NOx to nitrogen gas and water in the presence of ammonia, wherein the selective catalytic reactor is positioned downstream of the catalytic device.
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Abstract
Disclosed are apparatuses, systems, and methods for treating exhaust. The disclosed apparatus and systems typically include a catalytic device for converting aqueous urea to ammonia. The catalytic device may include a pyrolysis catalyst and a hydrolysis catalyst for converting aqueous urea to ammonia. The catalytic device typically includes an upstream face that is positioned at an angle relative to exhaust flow when the device is positioned in a selective catalytic reduction (SCR) system.
120 Citations
18 Claims
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1. An apparatus for treating exhaust comprising:
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(a) a housing having an upstream inlet for receiving the exhaust, and a downstream outlet for discharging the exhaust, the housing defining an axial flow path for the exhaust; (b) an injector configured to inject a urea solution into the exhaust; (c) a permeable catalytic device for converting urea to ammonia positioned in the axial flow path downstream of the injector, wherein the catalytic device has an upstream face that is positioned at an angle of about 20-70 degrees relative to the axial flow path and the catalytic device is configured to receive the urea solution from the injector at the upstream face; and (d) a selective catalytic reactor for converting NOx to nitrogen gas and water in the presence of ammonia, wherein the selective catalytic reactor is positioned downstream of the catalytic device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of manufacturing an apparatus for treating exhaust comprising:
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(a) providing a housing having an upstream inlet for receiving the exhaust, and a downstream outlet for discharging the exhaust, the housing defining an axial flow path for the exhaust; (b) positioning in the housing an injector for injecting a urea solution into the exhaust; and (c) positioning downstream of the injector a catalytic device for converting urea to ammonia, the catalytic device having an upstream face that is positioned at an angle of about 20-70 degrees relative to the axial flow path, and the catalytic device configured to receive the urea solution from the injector at the upstream face. - View Dependent Claims (14)
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- 15. A permeable catalytic device for converting urea to ammonia comprising a separate first portion and a separate second portion, and the first portion comprises a pyrolysis catalyst and the second portion comprises a hydrolysis catalyst, wherein the first portion and the second portion are positioned adjacent to each other to form the catalytic device, and the catalytic device is one of parallelogram-shaped in cross-section and trapezoid-shaped in cross-section.
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17. A method of manufacturing a permeable catalytic device for converting urea to ammonia, the device comprising a pyrolysis catalyst and a hydrolysis catalyst, the method comprising:
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(a) manufacturing a first portion of the device, wherein the first portion comprises the pyrolysis catalyst and has an upstream face and a downstream face; (b) manufacturing a second portion of the device, wherein the second portion comprises the hydrolysis catalyst and has an upstream face and a downstream face; and (c) positioning the downstream face of the first portion adjacent to the upstream face of the second portion, thereby forming the device; wherein the manufactured device is parallelogram-shaped in cross-section or trapezoid-shaped in cross-section. - View Dependent Claims (18)
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Specification