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1. (WO2019049046) PROCÉDÉ ET APPAREIL ASSOCIÉS À UN BRÛLEUR DE COMBUSTION À FAIBLES ÉMISSIONS DE NOX ET DE CO
Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

What is claimed is:

1. A method of discharging fuel and an amount of air into a furnace space wherein the fuel is burned such that flue gases having low NOx content and low CO content are formed therefrom, the method comprises:

mixing a first portion of the fuel and substantially all of the air to form a lean primary fuel- air mixture;

discharging the lean primary fuel-air mixture into the furnace space within a primary combustion zone defined by a burner tile such that there is a furnace environment surrounding the burner tile;

burning the primary fuel-air mixture in the primary combustion zone to produce a flame and thus generated flue gases, wherein the primary combustion zone has a first end and a second end, and the lean primary fuel-air mixture is introduced so that the flame is anchored adjacent the first end and the generated flue gases are discharged into the furnace environment at the second end.

2. The method of claim 1 , wherein the discharging of the lean primary fuel-air mixture is through at least one tube in which the first portion of the fuel and substantially all the air are mixed to form the fuel-air mixture, and wherein the first end of the combustion zone is closed to air introduction other than through the venturi tubes.

3. The method of claim 1, further comprising introducing a second portion of fuel into the furnace outside of the primary combustion zone such that the second portion of fuel forms a secondary combustion zone downstream of the primary combustion zone and substantially all the air for the secondary combustion zone is provided by the lean primary fuel-air mixture.

4. The method of claim 3, wherein substantially all the air is at least 97% of the air needed for combustion of the fuel based on the air needed to combust the first portion of the fuel, and the second portion of the fuel.

5. The method of claim 3, further comprising:

determining the composition of the fuel;

determining a flow rate of the first portion of the fuel and a flow rate of the second portion of the fuel;

determining an adiabatic flame temperature (AFT) for the composition of the fuel; determining the excess air quantity required to produce a predetermined NOx emission level based on the AFT; and

adjusting at least one of the flow rate of the first portion of fuel, the flow rate of the second portion of fuel, the amount of air based on the excess air quantity required to minimize NOx, and the distribution of air within the burner.

6. The method of claim 5, wherein the step of adjusting comprises adjusting both the flow rate of the first portion of fuel and the flow rate of the second portion of the fuel.

7. The method of claim 6, wherein the flow rate of the first portion of the fuel and the flow rate of the second portion of the fuel are adjusted simultaneously.

8. The method of claim 7, wherein the discharging of the lean primary fuel-air mixture is through a plurality of tubes in which all the air for the primary combustion zone and secondary combustion zone, and the first portion of the fuel are mixed to form the fuel-air mixture, and wherein the fuel-air mixture is supplied to the first combustion zone only through the tubes.

9. A fuel gas burner apparatus comprising:

a plenum including:

a first end attached to a furnace;

a second end opposing the first end; and

a sidewall connecting the first end and the second end together, wherein at least one of the sidewall and the second end has an air inlet disposed therein;

a burner tile including:

a base attached to the upper end of the plenum;

a discharge end opposing the base, the discharge end defining a discharge outlet; and

a wall connecting the base to the discharge end and surrounding the discharge outlet, the wall extending into the furnace, and having an interior surface defining a primary combustion chamber and an exterior surface;

a plurality of flame holders located within the combustion chamber; a plurality of primary fuel tips extending into the plenum; and

a plurality of primary tubes, wherein:

a first portion of the primary tubes wherein each primary tube in the first portion has an introduction end located within the plenum and a discharge end located within the primary combustion chamber, the first portion of primary tubes are associated with the plurality of primary fuel tips such that fuel from the primary fuel tips flows into the introduction ends of the first portion of primary tubes and draws air from inside the plenum into the introduction end so as to generate a fuel-air mixture, and the discharge end is located relative to the flame holders such that fuel-air mixture is introduced into the primary combustion chamber through the discharge end so as to encounter the flame holder; and

at least one of the primary tubes is an ignition unit; and

wherein the bottom end of the tile and the upper end of the plenum are closed to air flow such that air does not pass from the plenum to the tile except through one or more of the primary tubes; and

a plurality of secondary fuel tips connected to a source of fuel gas and operably associated with the burner apparatus such that secondary stage fuel gas is injected from outside of the burner tile to a point downstream from the discharge outlet of the burner tile.

10. The fuel gas burner apparatus of claim 9, wherein the burner is configured such that substantially all the air for combustion of fuel introduced into the furnace is introduced through the primary tubes.

11. The fuel gas burner apparatus of claim 10, wherein the burner is configured such that substantially all the air for combustion of fuel introduced into the furnace is introduced through the first portion of the primary tubes.

12. The fuel gas burner apparatus of claim 9, further comprising a control unit wherein the amount of fuel being introduced through the primary fuel tips and secondary fuel tips can be controlled.

13. The fuel gas burner apparatus of claim 9, wherein the flame holders are attached to the discharge end of the first portion of primary tubes.

14. The fuel gas burner apparatus of claim 13, wherein the flame holders have a shape selected from a cylindrical shape with perforation, a cup shape, cone shape and pyramid shape.

15. The fuel gas burner apparatus of claim 9, wherein the ignition unit comprises:

a riser tube having an inner surface, a first end and a second end, wherein the second end is within the tile and in fluid flow contact with the combustion chamber;

a fuel lance having a first end in fluid flow contact with a fuel supply and a second end within the riser tube, wherein the second end has a discharge nozzle configured to inject fuel so as to move circumferentially and longitudinally within riser tube and passes out of the second end of the riser tube into the combustion chamber; and

an ignitor which ignites the fuel air mixture passing through the second end of the riser tube.

16. The fuel gas burner apparatus of claim 15, wherein the second end of the riser tube further includes a s wirier cup having a curved and divergent wall.

17. The fuel gas burner apparatus of claim 16, wherein the first end is configured to allow entrance of air into the riser tube such that fuel from the discharge nozzle mixes with air passing through the riser tube to generate a swirling air-fuel mixture.

18. The fuel gas burner apparatus in claim 9, where the ignition unit comprises:

a fuel lance having a first end in fluid flow contact with a fuel supply and a second end, wherein the second end is within the combustion chamber and has at least one discharge nozzle configured to discharge fuel inside the combustion chamber circumferentially along the interior surface of the wall of the tile; and

an ignitor which ignites the fuel passing through the discharge nozzle.

19. The fuel gas burner apparatus of claim 9, wherein the riser tube further comprises one or more legs extending out from the riser tube towards the interior surface of the wall of the tile and wherein the legs terminate adjacent the interior surface of the wall in one or more of the discharge nozzles.

20. The fuel gas burner apparatus of claim 19, wherein the nozzles are located in a cavity formed by a ledge on the interior surface of the wall and a ring connected to the ledge.

21. The fuel gas burner apparatus of claim 18, wherein the fuel discharged from the discharge nozzle is in a fuel-air mixture.

22. The fuel gas burner apparatus of claim 9, further comprising:

one or more sensors to measure fuel flow rate of a primary fuel introduced through the primary tubes and fuel flow rate of a secondary fuel introduced through the secondary fuel tips;

one or more valves for controlling the fuel flow rate of the primary fuel and the fuel flow rate of the secondary fuel; and

a computer processing system operatively connected to the sensors and valves, and configured to adjust the flow rates of the primary fuel and the fuel flow rate of the secondary fuel based on one or more of the composition of the primary and secondary fuel, the adiabatic flame temperature of the primary and secondary fuel, and measured values for the quantity of NOx emissions.

23. The fuel gas burner apparatus of claim 22, wherein the burner is configured such that substantially all the air for combustion of fuel introduced into the furnace is introduced through the primary tubes.

24. The fuel gas burner apparatus of claim 23, wherein the flame holders are attached to discharge end of the primary tubes.

25. A process for controlling NOx content in emissions from a system wherein a primary fuel is combusted in a primary combustion zone with a primary amount of air, wherein the combustion in the primary combustion zone leaves an air quantity, and a secondary fuel is combusted in a secondary combustion zone with the air quantity from the combustion in the primary combustion zone and leaves an excess air quantity, the method comprising the steps of:

determining the composition of the primary fuel and secondary fuel; determining a flow rate of primary fuel into the system and a flow rate of secondary fuel into the system;

determining an adiabatic flame temperature (AFT) for the composition of the primary fuel and secondary fuel;

determining the excess air quantity required to produce a predetermined NOx emission level based on the AFT; and

adjusting at least one of the flow rate of primary fuel, the flow rate of secondary fuel, the primary amount of air based on the excess air quantity required to minimize NOx, and the distribution of air within the burner.

26. The process of claim 25, wherein substantially all the air for both the primary combustion zone and secondary combustion zone is provided by the primary amount of air.

27. The process of claim 25, wherein the step of adjusting comprises adjusting both the flow rate of the primary fuel and the flow rate of the secondary fuel.

28. The process of claim 27, wherein the flow rate of the primary fuel and the flow rate of the secondary fuel are adjusted simultaneously.

29. The process of claim 28, wherein all the air for both the primary combustion zone and secondary combustion zone is provided by the primary amount of air.

30. The process of claim 25, further comprising providing a secondary amount of air to the secondary combustion zone, and wherein the step of adjusting comprises adjusting the primary amount of air and secondary amount of air.

31. The process of claim 30, wherein the primary amount of air and the secondary amount of air are adjusted simultaneously.

32. A system for controlling NOx content in emissions from furnace, the system comprising:

a burner tile defining a primary combustion chamber;

a plurality of primary tubes connected to a source of fuel gas and a source of combustion air and which are configured to form an air-fuel mixture and are operably associated with the furnace so as to introduce the air-fuel mixture into the primary combustion chamber;

a plurality of secondary fuel tips connected to the source of fuel gas and operably associated with the furnace such that fuel gas is injected from outside of the burner tile to a point downstream from the primary combustion zone so as to produce a secondary combustion zone;

a computer processing system operatively connected to the primary injectors and the secondary injectors so as to adjust flow rates through the primary fuel tubes and the secondary fuel tips based on one or more of the composition of the fuel gas, the adiabatic flame temperature of the fuel gas, and measured values for the quantity of NOx emissions from the furnace.

33. The system of claim 32, wherein the computer processing system is configured to: determine the composition of the fuel gas;

determine a flow rate of fuel gas into the system through the primary tubes and a flow rate of fuel into the system through the secondary fuel tips;

determine an adiabatic flame temperature (AFT) for the composition of the fuel gas; and

determine excess combustion-air quantity required to produce a predetermined NOx emission level based on the AFT.

34. The system of claim 33, further comprising:

a first set of sensors which measure the flow rate of fuel gas through the primary tubes;

a second set of sensors which measure the flow rate of fuel gas through the secondary fuel tips;

a first set of valves configured to adjust the flow rate of the fuel gas through the primary tubes; and

a second set of valves configured to adjust the flow rate of fuel gas through the secondary fuel tips.

35. The system of claim 34, wherein:

each of the primary tubes has an introduction end located within a plenum and a discharge end located within the combustion chamber, the primary tubes are associated with a plurality of primary fuel tips such that fuel from the primary fuel tips flows into the introduction end of the primary tubes and draws combustion air from inside the plenum into the introduction end so as to generate a fuel-air mixture, and the discharge end is located relative to flame holders in the combustion chamber such that fuel air mixture is injected into the combustion chamber through the discharge end so as to encounter the flame holder; and

airflow communication between the tile and the plenum is closed such that combustion air does not pass from the plenum to the combustion chamber of the tile except through one or more of the primary tubes.

36. The fuel gas burner apparatus of claim 35, wherein the burner is configured such that substantially all the combustion air for both the primary combustion zone and the secondary combustion zone is provided through the primary tubes.

37. The system of claim 35, wherein the flow rate of the fuel gas through the primary tubes and the flow rate of the fuel gas through the secondary fuel tips are adjusted simultaneously.

38. The system of claim 37, wherein all the combustion air for both the primary combustion zone and the secondary combustion zone is provided through the primary tubes.

39. The system of claim 37, further comprising a secondary air introduction tube which provides a secondary amount of combustion air to the secondary combustion zone, and wherein the computer processing system is operatively connected to the secondary air introduction tube so as to adjust the secondary amount of combustion air provided to the secondary combustion zone.