Method and device for diluted combustion

1. A burner apparatus for diluted combustion, comprising:

a combustion chamber;

a fuel nozzle for supplying fuel to the combustion chamber;

a plurality of air nozzles arranged in a circle around the fuel nozzle for supplying a plurality of air streams to the combustion chamber; and

a plurality of oxygen nozzles arranged in the circle around the fuel nozzle for supplying a plurality of oxygen streams to the combustion chamber, the oxygen nozzle alternating with the air nozzles along the circle and spatially separated and offset from the plurality of air nozzles.

2. A burner for diluted combustion, comprising:

a fuel nozzle for supplying fuel to a combustion chamber;

a plurality of air nozzles arranged in a circle around the fuel nozzle for supplying a plurality of aft streams to the combustion chamber; and

a plurality of oxygen nozzles for supplying a plurality of oxygen streams to the combustion chamber, the plurality of oxygen nozzles spatially separated in the circle from the plurality of air nozzles;

wherein the separate air nozzles and oxygen nozzles alternate along the circle and are offset from each other.

3. The burner according to claim 2 , further comprising a controller in communication with at least one air nozzle and at least one oxygen nozzle to switch between operation with air, operation with oxygen, and operation with oxygen and air, during combustion.

4. The burner according to claim 2 , further comprising an additional oxygen nozzle arranged centrally in the fuel nozzle.

5. The burner according to claim 2 , wherein the plurality of oxygen nozzles comprises from 2 to 12 oxygen nozzles, and the plurality of air nozzles comprises from 2 to 12 air nozzles.

6. The burner according to claim 2 , further comprising at least one port for connection with an oxygen source, and at least one port for connection with an air source.

7. A method for diluted combustion, comprising:

supplying a fuel stream, a plurality of air streams and a plurality of oxygen streams from a burner into a combustion chamber;

spatially separating the plurality of air streams and oxygen streams from each other as separate streams arranged in a circle around said fuel stream with each of the separate air streams and oxygen streams alternating along the circle and offset from each other; and

adjusting volumetric streams of the plurality of air and oxygen streams independently of each other for selecting between pure operation with the air streams, pure operation with the oxygen streams, and mixed operation with the oxygen and the air streams during the combustion.

8. The method according to claim 7 , wherein the supplying comprises the plurality of air and oxygen streams exiting the burner in a direction substantially parallel to a longitudinal direction of the burner.

9. The method according to claim 7 , further comprising operating the burner with oxygen during run up, and optionally with the plurality of air streams, the plurality of oxygen streams, or a mixture of the air and oxygen streams in normal operation as an oxidant for the combustion.

10. The method according to claim 7 , further comprising:

supplying a central oxygen stream to the combustion chamber;

centrally locating the central oxygen stream in the fuel stream;

enveloping the central oxygen stream with the fuel stream; and

forming an ancillary flame with the central oxygen stream and a portion of fuel in the fuel stream.

11. The method according to claim 7 , further comprising recirculating exhaust gas in the combustion chamber, said recirculating occurring internally or externally of the combustion chamber.

12. The method according to claim 7 , further comprising exposing the combustion chamber to additional oxygen streams having a speed of from at least 50 m/s to 200 m/s.

13. The method according to claim 12 , further comprising enveloping the fuel stream substantially concentrically with the additional oxygen streams.

14. The method according to claim 7 , further comprising exposing the combustion chamber to additional air streams having a speed of at least from 50 m/s to 150 m/s.

15. The method according to claim 14 , further comprising enveloping the fuel stream substantially concentrically with the additional air streams.

16. The method according to claim 7 , further comprising:

exposing the combustion chamber to additional oxygen streams having a speed of from at least 50 m/s to 200 m/s, and enveloping the fuel stream substantially concentrically with the additional oxygen streams; and

exposing the combustion chamber to additional air streams having a speed of from at least 50 m/s to 150 m/s, and enveloping the fuel stream substantially concentrically with the additional air streams.

17. The method according to one of claim 7 , wherein the fuel stream has a speed of from at least 50 m/s to 90 m/s.