System and method for exhaust treatment

Patent metadata

Field	Value
Publication number	US-9784157-B2
Application number	US-73117110-A
Country	US
Kind code	B2
Filing date	Mar 25, 2010
Priority date	Mar 25, 2010
Publication date	Oct 10, 2017
Grant date	Oct 10, 2017

Abstract

According to various embodiments, an exhaust treatment system includes a catalyst that is in direct contact with an exhaust stream, at least one sensor that senses a system parameter and produces one or more signals corresponding to the system parameter, and a controller that is configured to receive the one or more signals and control catalyst performance based on the one or more signals by regenerating the catalyst. Regenerating the catalyst includes increasing a temperature of the exhaust stream flowing to the catalyst and directing a reductant injector to adjust a flow rate of reductant being injected into the exhaust stream flowing to the catalyst.

First claim

The invention claimed is:

1. An exhaust treatment system, comprising:
a catalyst that is in direct contact with an exhaust stream;
at least one sensor that senses a system parameter and produces one or more signals corresponding to the system parameter; and
a controller that is configured to receive the one or more signals and control catalyst performance based on the one or more signals by regenerating the catalyst, wherein regenerating the catalyst comprises:
increasing a temperature of the exhaust stream flowing to the catalyst; and
directing a reductant injector to adjust a flow rate of reductant being injected into the exhaust stream flowing to the catalyst; and
wherein the controller regenerates the catalyst at a temperature and for a duration based on the temperature of the exhaust stream flowing to the catalyst since the catalyst was last regenerated.

2. The system of claim 1 , wherein the catalyst comprises a hydrocarbon selective catalytic reduction (HC-SCR) catalyst.

3. The system of claim 1 , wherein regenerating the catalyst comprises operating at an oxygen concentration greater than about 3%.

4. The system of claim 1 , wherein a respective system parameter comprises at least one of:
a post-catalyst concentration of NO x in the exhaust stream;
a pre-catalyst concentration of NO x in the exhaust stream;
a duration the catalyst has been in direct contact with the exhaust stream since the catalyst was last regenerated;
an amount of exhaust that has been in direct contact with the catalyst since the catalyst was last regenerated;
a mass or volumetric flow rate of the exhaust stream that has been in direct contact with the catalyst since the catalyst was last regenerated;
a mass or volumetric flow rate of a fuel stream and/or an air stream directed to a source of the exhaust stream since the catalyst was last regenerated;
a speed and/or a power of the source of the exhaust stream;
a temperature of the exhaust stream flowing to the catalyst; or
any combination thereof.

5. The system of claim 1 , wherein catalyst performance comprises a post-catalyst concentration of NO x in the exhaust stream.

6. The system of claim 1 , wherein increasing the temperature of the exhaust stream flowing to the catalyst comprises using an exhaust stream heater.

7. The system of claim 6 , wherein the exhaust stream heater comprises a homogeneous burner that burns fuel, a diesel oxidation catalyst that combusts fuel catalytically, an electric heater that heats the exhaust stream, or any combination thereof.

8. The system of claim 1 , wherein increasing the temperature of the exhaust stream flowing to the catalyst comprises operating a source of the exhaust stream in a mode that causes increased exhaust stream temperature.

9. The system of claim 8 , wherein the mode that causes increased exhaust stream temperature comprises operating the source of the exhaust stream inefficiently, bypassing a turbocharger, or any combination thereof.

10. The system of claim 1 , wherein the temperature of the exhaust stream flowing to the catalyst is increased to about 450 degrees Celsius to 500 degrees Celsius.

11. A method for treating an exhaust, comprising:
passing an exhaust stream in direct contact with a catalyst;
sensing a system parameter by at least one sensor and producing one or more signals corresponding to the system parameter;
transmitting the one or more signals to a controller; and
controlling catalyst performance based on the one or more signals by regenerating the catalyst, wherein regenerating the catalyst comprises:
increasing a temperature of the exhaust stream flowing to the catalyst; and
adjusting a flow rate of a reductant being injected into the exhaust stream flowing to the catalyst;
wherein the controller regenerates the catalyst at a temperature for a duration based on the temperature of the exhaust stream flowing to the catalyst since the catalyst was last regenerated.

12. The method of claim 11 , wherein the catalyst comprises a hydrocarbon selective catalytic reduction (HC-SCR) catalyst.

13. The method of claim 11 , wherein regenerating the catalyst comprises operating at an oxygen concentration greater than about 3%.

14. The method of claim 11 , wherein a respective system parameter comprises:
a post-catalyst concentration of NO x in the exhaust stream;
a pre-catalyst concentration of NO x in the exhaust stream;
a duration the catalyst has been in direct contact with the exhaust stream since the catalyst was last regenerated;
an amount of exhaust that has been in direct contact with the catalyst since the catalyst was last regenerated;
a mass or volumetric flow rate of the exhaust stream that has been in direct contact with the catalyst since the catalyst was last regenerated;
a mass or volumetric flow rate of a fuel stream and/or an air stream directed to a source of the exhaust stream since the catalyst was last regenerated;
a speed and/or a power of the source of the exhaust stream;
a temperature of the exhaust stream flowing to the catalyst; or
any combination thereof.

15. The system of claim 11 , wherein catalyst performance comprises a post-catalyst concentration of NO x in the exhaust stream.

16. The system of claim 11 , wherein increasing the temperature of the exhaust stream flowing to the catalyst comprises using an exhaust stream heater.

17. The system of claim 16 , wherein the exhaust stream heater burns fuel in a homogeneous burner, combusts fuel catalytically in a diesel oxidation catalyst fuel, heats the exhaust stream using an electric heater, or any combination thereof.

18. The system of claim 11 , wherein increasing the temperature of the exhaust stream flowing to the catalyst comprises operating a source of the exhaust stream in a mode that causes increased exhaust stream temperature.

19. The system of claim 18 , wherein the mode that causes increased exhaust stream temperature comprises operating the source of the exhaust stream inefficiently, bypassing a turbocharger, or any combination thereof.

20. The system of claim 11 , wherein the temperature of the exhaust stream flowing to the catalyst is increased to about 450 degrees Celsius to 500 degrees Celsius.

21. A fuel-burning system comprising:
a catalyst that is connected to a source of an exhaust stream and is in direct contact with the exhaust stream;
a sensor that senses a concentration of NO x in the exhaust stream and produces a signal corresponding to the concentration of NO x in the exhaust stream; and
a controller that is configured to receive the signal, compare a value of the concentration of NO x in the exhaust stream with a setpoint, and increase a temperature of the exhaust stream flowing to the catalyst and adjust a flow rate of reductant being injected into the exhaust stream flowing to the catalyst to oxidize hydrocarbons disposed on the catalyst if the value of the concentration of NO x in the exhaust stream is greater than the setpoint; and
wherein the controller regenerates the catalyst at a temperature and for a duration based on the temperature of the exhaust stream flowing to the catalyst since the catalyst was last regenerated.

22. The system of claim 21 , wherein the source of the exhaust stream comprises a diesel engine that comprises at least one cylinder that produces the exhaust stream.

23. The system of claim 22 , wherein the diesel engine is disposed in at least one of: a locomotive, a passenger vehi

Assignees

• Norton Daniel George
• Buddle Stanlee Teresa
• Hancu Dan
• Winkler Benjamin Hale
• Mhadeshwar Ashish Balkrishna
• Gen Electric

Inventors

• Norton Daniel George
• Buddle Stanlee Teresa
• Hancu Dan
• Winkler Benjamin Hale
• Mhadeshwar Ashish Balkrishna

Classifications

• Y02T10/47

  Cross-Sectional Technologies · mapped topic

• F01N3/0885 Primary

  Regeneration of deteriorated absorbents or adsorbents, e.g. desulfurization of NOx traps · CPC title

• F01N3/106

  Auxiliary oxidation catalysts · CPC title

• F01N2900/0422

  measuring the elapsed time · CPC title

• F01N2560/026

  for measuring or detecting NOx · CPC title