Integration of oxy-fuel and air-fuel combustion

Abstract

A furnace is heated by a burner that can be selectively operated by either air-fuel or oxy-fuel combustion. The burner comprises a conduit for fuel, a conduit for air, a conduit for oxidant, and control means for regulating flow through the air and oxidant conduits. An air-fuel fired furnace can be modified by addition of the oxidant and fuel conduits and the control means for regulating flow through air and oxidant conduits.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a burner with which the present invention can be practiced.

FIG. 2 is a cross-sectional view of one embodiment of the present invention.

FIG. 3 is a plan view of a wall of a furnace showing the embodiment of the invention that is shown in FIG. 2.

FIG. 4 is a plan view of a wall of a furnace showing another embodiment of the present invention.

FIG. 5 is a plan view of a wall of a furnace showing yet another embodiment of the present invention.

FIG. 6 is a plan view of a wall of a furnace showing another embodiment of the present invention.

FIG. 7 is a schematic representation of combustion in one embodiment of the invention.

FIG. 8 is a schematic representation of combustion in another embodiment of the invention.

Claims

1. Combustion apparatus comprising (a) a furnace enclosing a combustion zone and having at least one burner through a wall of the furnace to which air is fed through an air conduit and fuel is fed through a burner fuel conduit from outside the furnace to be combusted at the burner within the combustion zone;(b) an oxidant conduit through which oxidant can be fed into the furnace from outside the furnace; and(c) control means that regulates the flow of oxidant through the oxidant conduit and the flow of air through the air conduit such that the ratio of air flow to oxidant flow can be controlled;wherein the oxidant conduit and the burner fuel conduit are oriented with respect to each other so that the oxidant conduit feeds oxidant into an oxidant mixing zone in the combustion zone and the burner fuel conduit feeds fuel into a fuel reaction zone in the combustion zone which is segregated from the oxidant mixing zone.

2. Combustion apparatus according to claim 1 wherein the oxidant conduit feeds oxidant into the furnace from within the burner.

3. Combustion apparatus according to claim 1 wherein the oxidant conduit feeds oxidant into the furnace from an opening that is not within a burner.

4. Combustion apparatus according to claim 1 further comprising a second fuel conduit through which fuel is fed from outside the furnace to be combusted within the combustion zone.

5. Combustion apparatus according to claim 4 wherein the oxidant conduit feeds oxidant into the furnace from within the burner.

6. Combustion apparatus according to claim 5 wherein the second fuel conduit feeds fuel into the furnace from within the burner.

7. Combustion apparatus according to claim 5 wherein the second fuel conduit feeds fuel into the furnace from an opening that is not within a burner.

8. Combustion apparatus according to claim 4 wherein the oxidant conduit feeds oxidant into the furnace from an opening that is not within a burner.

9. Combustion apparatus according to claim 8 wherein the second fuel conduit feeds fuel into the furnace from within the burner.

10. Combustion apparatus according to claim 8 wherein the second fuel conduit feeds fuel into the furnace from an opening that is not within a burner.

11. Burner apparatus comprising (a) a burner to which air is fed through an air conduit and fuel is fed through a burner fuel conduit to be combusted in a combustion zone at the burner;(b) an oxidant conduit through which oxidant can be fed to the burner; and(c) control means that regulates the flow of oxidant through the oxidant conduit and the flow of air through the air conduit such that the ratio of air flow to oxidant flow can be controlled;wherein the oxidant conduit and the burner fuel conduit are oriented with respect to each other so that the oxidant conduit feeds oxidant into an oxidant mixing zone in the combustion zone and the burner fuel conduit feeds fuel into a fuel reaction zone in the combustion zone which is segregated from the oxidant mixing zone.

12. Burner apparatus according to claim 11 wherein the oxidant conduit feeds oxidant into the furnace from within the burner.

13. Burner apparatus according to claim 11 wherein the oxidant conduit feeds oxidant into the furnace from an opening that is not within a burner.

14. Burner apparatus according to claim 11 further comprising a second fuel conduit through which fuel is fed to be combusted at the burner.

15. Burner apparatus according to claim 14 wherein the oxidant conduit feeds oxidant into the furnace from within the burner.

16. Burner apparatus according to claim 15 wherein the second fuel conduit feeds fuel into the furnace from within the burner.

17. Burner apparatus according to claim 15 wherein the second fuel conduit feeds fuel into the furnace from an opening that is not within a burner.

18. Burner apparatus according to claim 14 wherein the oxidant conduit feeds oxidant into the furnace from an opening that is not within a burner.

19. Burner apparatus according to claim 18 wherein the second fuel conduit feeds fuel into the furnace from within the burner.

20. Burner apparatus according to claim 18 wherein the second fuel conduit feeds fuel into the furnace from an opening that is not within a burner.

21. A method for retrofitting an air-fired furnace, comprising (a) providing a furnace enclosing a combustion zone and having at least one burner through a wall of the furnace to which air is fed through an air conduit and fuel is fed through a burner fuel conduit from outside the furnace to be combusted at the burner within the combustion zone;(b) providing an oxidant conduit through which oxidant can be fed into the furnace from outside the furnace;(c) providing control means that regulates the flow of oxidant through the oxidant conduit and the flow of air through the air conduit such that the ratio of air flow to oxidant flow can be controlled; and(d) orienting the oxidant conduit with respect to the burner fuel conduit so that the oxidant conduit feeds oxidant into an oxidant mixing zone in the combustion zone and the burner fuel conduit feeds fuel into a fuel reaction zone in the combustion zone which is segregated from the oxidant mixing zone.

22. A method according to claim 21 wherein the oxidant conduit feeds oxidant into the furnace from within the burner.

23. A method according to claim 21 wherein the oxidant conduit feeds oxidant into the furnace from an opening that is not within a burner.

24. A method for retrofitting an air-fired furnace, comprising (a) providing a furnace enclosing a combustion zone and having at least one burner through a wall of the furnace to which air is fed through an air conduit and fuel is fed through a burner fuel conduit from outside the furnace to be combusted at the burner within the combustion zone;(b) providing an oxidant conduit through which oxidant can be fed into the furnace from outside the furnace;(c) providing control means that regulates the flow of oxidant through the oxidant conduit and the flow of air through the air conduit such that the ratio of air flow to oxidant flow can be controlled;(d) providing a second fuel conduit through which fuel is fed from outside the furnace to be combusted within the combustion zone, and(e) orienting the oxidant conduit with respect to at least one of the burner fuel conduit and the second fuel conduit so that the oxidant conduit feeds oxidant into an oxidant mixing zone in the combustion zone and said fuel conduit feeds fuel into a fuel reaction zone in the combustion zone which is segregated from the oxidant mixing zone.

25. A method according to claim 24 wherein the oxidant conduit feeds oxidant into the furnace from within the burner.

26. A method according to claim 25 wherein the second fuel conduit feeds fuel into the furnace from within the burner.

27. A method according to claim 25 wherein the second fuel conduit feeds fuel into the furnace from an opening that is not within a burner.

28. A method according to claim 24 wherein the oxidant conduit feeds oxidant into the furnace from an opening that is not within a burner.

29. A method according to claim 28 wherein the second fuel conduit feeds fuel into the furnace from within the burner.

30. A method according to claim 28 wherein the second fuel conduit feeds fuel into the furnace from an opening that is not within a burner.