PLANT, COMBUSTION APPARATUS, AND METHOD FOR REDUCTION OF NOx EMISSIONS

Patent metadata

Field	Value
Publication number	US-2016146462-A1
Application number	US-201414550101-A
Country	US
Kind code	A1
Filing date	Nov 21, 2014
Priority date	Nov 21, 2014
Publication date	May 26, 2016
Grant date	—

Abstract

A combustion apparatus includes a combustion chamber having multiple combustion zones. A first wind box is in communication with the first combustion zone to feed the fuel to be fed into the combustion chamber for initial combustion of the fuel within the first combustion zone. A second wind box has a reburner in communication with the second combustion zone. The reburner is configured to feed fuel, a reagent and a first portion of the flue gas to be recycled to the second combustion zone into the second combustion zone to reduce nitrogen oxide emissions of the apparatus. A third wind box is in communication with the third combustion zone to feed air to the third combustion zone to complete the combustion process.

First claim

What is claimed is:

1 . A combustion apparatus, comprising:
a combustion chamber having multiple combustion zones for combustion of fuel, the combustion zones including a first combustion zone, a second combustion zone, and a third combustion zone wherein the second combustion zone is located between the first and third combustion zones, the combustion chamber having at least one outlet configured to emit flue gas formed from combustion of the fuel in the combustion chamber; a first wind box in communication with the first combustion zone for feeding of fuel into the combustion chamber for initial combustion within the first combustion zone; a second wind box in communication with second combustion zone to feed a first gas having oxygen into the second combustion zone; a third wind box in communication with the third combustion zone to feed a second gas having oxygen into the third combustion zone; and a conduit in communication with the second combustion zone to feed a reagent into the second combustion zone.

2 . The combustion apparatus of claim 1 , wherein the second wind box has a reburner in communication with the second combustion zone, the reburner configured to feed fuel into the second combustion zone and also feed the reagent into the second combustion zone.

3 . The combustion apparatus of claim 2 , wherein the reburner comprises a nozzle that is configured to spray the reagent into the second combustion zone with the fuel fed to the second combustion zone via the second feed conduit.

4 . The combustion apparatus of claim 1 , wherein the first and second gases are air.

5 . The combustion apparatus of claim 2 , wherein each of the first, second and third feed conduits comprise at least one wind box.

6 . The combustion apparatus of claim 5 , wherein the reburner is positioned at an upper compartment of the second wind box or is positioned above the second wind box between the second wind box and the third wind box.

7 . The combustion apparatus of claim 1 , wherein at least one of the first, second, and third wind boxes are configured to facilitate tangential firing of fuel.

8 . The combustion apparatus of claim 2 , wherein the reburner is also configured to feed a first portion of the flue gas to be recycled into the second combustion zone.

9 . The combustion apparatus of claim 1 , wherein the reagent is provided to the second combustion zone at an upper compartment of the second wind box or is positioned above the second wind box between the second wind box and the third wind box.

10 . The combustion apparatus of claim 1 , wherein the second wind box is configured to feed a first portion of the flue gas to be recycled into the second combustion zone with the reagent to facilitate mixing of the reagent within the second combustion zone.

11 . A method of operating a combustion apparatus having a combustion chamber including a first combustion zone, a second combustion zone, and a third combustion zone wherein the second combustion zone is located between the first and third combustion zones; the method comprising:
providing a first fuel into the first combustion zone of the combustion chamber; providing a reagent and a first gas having oxygen to the second combustion zone of the combustion chamber; and providing a second gas having oxygen to the third combustion zone of the combustion chamber.

12 . The method of claim 11 further comprising:
feeding a second fuel to the second combustion zone, wherein the reagent and the second fuel are simultaneously fed to the second combustion zone.

13 . The method of claim 12 further comprising:
recycling a first portion of flue gas exiting the combustion chamber to the second combustion zone such that the reagent, the second fuel and the first portion of the flue gas are simultaneously fed to the second combustion zone.

14 . The method of claim 13 wherein the first and second gases are air.

15 . The method of claim 12 , wherein:
the first fuel is coal and the first fuel is fed into the first combustion zone; the second fuel is natural gas or oil; and the reagent is one of aqueous ammonia, aqueous urea, and anhydrous ammonia.

16 . The method of claim 12 , wherein:
the first, second, and third combustion zones are each positioned adjacent to a respective wind box; and the second fuel being fed into the second combustion zone via a sole reburner of the wind box of the second combustion zone, the reburner being positioned at one of:
an upper compartment of the wind box of the second combustion zone, and
above the wind box of the second combustion zone between the wind box of the second combustion zone and the wind box of the third combustion zone.

17 . The method of claim 11 , wherein the feeding of the first fuel into the combustion chamber comprises feeding the first fuel into the first combustion zone, the method also comprising:
feeding a second fuel to the second combustion zone, the second fuel differing from the first fuel such that the reagent and the second fuel are simultaneously fed to the second combustion zone; and combusting the first fuel in the combustion chamber via a tangential firing system.

18 . The method of claim 11 , wherein the reagent is a liquid and is sprayed into the second combustion zone.

19 . The method of claim 18 , wherein the reagent is fed into the second combustion zone while no fuel is fed into the second combustion zone via a reburner.

20 . The method of claim 12 , wherein the reagent is provided to the second combustion zone above the location where the gas having oxygen is provided to the second combustion zone.

Assignees

• Alstom Technology Ltd

Inventors

• Cohen Mitchell B
• Hellewell Todd D

Classifications

• F23C9/00

  Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber (fluidised bed combustion apparatus with means for recirculation of particles entrained from the bed F23C10/02; fluidised bed combustion apparatus with devices for removal and partial reintroduction of material from the bed F23C10/26) · CPC title

• F23C6/047

  with fuel supply in stages · CPC title

• F23J7/00 Primary

  Arrangement of devices for supplying chemicals to fire · CPC title

• F23C9/06

  for completing combustion · CPC title

• F23D14/20

  Non-premix gas burners, i.e. in which gaseous fuel is mixed with combustion air on arrival at the combustion zone (F23D14/38 takes precedence) · CPC title