Method and apparatus for reducing a nitrogen oxide, and control thereof

• US 8,323,574 B2
• Filed: 08/17/2009
• Issued: 12/04/2012
• Est. Priority Date: 06/19/2002
• Status: Expired due to Fees

• Current Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Steichen, John Carl, Morris, Patricia A., Barnes, John James
• Primary Examiner(s): Warden, Jill
• Assistant Examiner(s): COLE, MONIQUE T
• Application Number:
  US12/542,210
• Publication Number:
  US 20090304559A1
• Time in Patent Office: 1,205 Days
• Field of Search: 436/118, 602/72, 602/74, 602/82, 602/86, 602/99, 603/01, 603/02, 603/03, 422/62, 422/83, 422/98
• US Class Current: 422/83
• CPC Class Codes: B01D 53/346 Controlling the process
• CPC Class Codes: B01D 53/56 Nitrogen oxides B01D53/60 takes precedence
• CPC Class Codes: B01D 53/79 Injecting reactants
• CPC Class Codes: B01D 53/8625 Nitrogen oxides
• CPC Class Codes: B01D 53/8696 Controlling the catalytic process
• CPC Class Codes: B01D 53/90 Injecting reactants
• CPC Class Codes: F01N 2560/02 the means being an exhaust gas sensor
• CPC Class Codes: F01N 2610/02 the substance being ammonia or urea
• CPC Class Codes: F01N 3/2066 Selective catalytic reduction [SCR]
• CPC Class Codes: G01N 33/0037 for NOx
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y10T 436/100833 Simulative of a gaseous composition
• CPC Class Codes: Y10T 436/12 Condition responsive control
• CPC Class Codes: Y10T 436/17 Nitrogen containing
• CPC Class Codes: Y10T 436/177692 Oxides of nitrogen
• CPC Class Codes: Y10T 436/178459 Only nitrogen dioxide
• CPC Class Codes: Y10T 436/179228 Both nitrogen oxide and dioxide

Abstract

Disclosed herein is a method and apparatus for reducing a nitrogen oxide, and the control thereof.

Claims

1. An apparatus for reducing a nitrogen oxide gas emitted by a emissions source, comprising

(a) an emissions source,

(b) an exhaust conduit for transporting the nitrogen oxide gas downstream from the emissions source,

(c) an injector for injecting a reducing agent into the conduit, and

(d) one or more gas analyzers located in the conduit upstream from the injector,

wherein a gas analyzer comprises an array of chemo/electro-active materials selected as a member from the group of five arrays of chemo/electro-active material consisting of:

(i) an array comprising SnO_x, Nb_aTi_bO_x, and Ni_aZn_bO_x;

(ii) an array comprising ZnO_x, Ti_aZn_bO_x, and Ta_aTi_bO_x;

(iii) an array comprising Sb_aSn_bO_x, Ta_aTi_bO_x, and Ti_aZn_bO_x;

(iv) an array comprising SnO_x, Ta_aTi_bO_x, and Ti_aZn_bO_x; and

(v) an array comprising Ni_aZn_bO_x, SnO_x, and Ta_aTi_bO_x;

wherein a, b and c are each independently about 0.0005 to about 1; and

wherein x is a number sufficient so that the oxygen present balances the charges of the other elements in the chemo/electro-active material.

2. An apparatus according to claim 1 further comprising a catalyst to catalyze the reduction of the nitrogen oxide.

3. An apparatus according to claim 2 further comprising a gas analyzer that is downstream from the injector and downstream from a catalyst.

4. An apparatus according to claim 2 wherein a first gas analyzer is located upstream from a catalyst, and a second gas analyzer is located downstream from the catalyst.

5. An apparatus according to claim 2 that comprises a plurality of gas analyzers, wherein a plurality of gas analyzers is located upstream from a catalyst, and a plurality of gas analyzers is located downstream from the catalyst.

6. An apparatus according to claim 2 comprising (a) a first catalyst, (b) a gas analyzer located downstream from the first catalyst, and (c) a second catalyst located downstream from the gas analyzer.

7. An apparatus according to claim 6 wherein the first and second catalysts is each a catalyst bed in vertical arrangement.

8. An apparatus according to claim 6 further comprising a plurality of gas analyzers located between the first and second catalysts.

9. An apparatus according to claim 6 further comprising one or more gas analyzers downstream from the second catalyst.

10. An apparatus according to claim 2 further comprising one or more gas analyzers downstream from all catalysts.

11. An apparatus according to claim 1 or 2 wherein the reducing agent is ammonia.

12. An apparatus according to claim 1 or 2 wherein the reducing agent is urea.

13. An apparatus according to claim 1 or 2 wherein the emissions source is stationary.