BURNER ASSEMBLY HAVING A MODIFIED TILE

Abstract

Process and apparatuses for providing a stable flame in a burner assembly are provided. In an embodiment, the apparatus includes a burner assembly comprising a burner tile having a top surface, an outside surface, a pre-mix region and defining an interior space for introduction of combustion air. A plurality of primary fuel tips are disposed in the interior space for injection of a primary fuel followed by mixing of a portion of the primary fuel and a portion of the combustion air mix in the pre-mix region to provide a primary fuel-air mixture. A plurality of secondary fuel tips are located on the top surface or mounted near the outside surface of the burner tile. A plurality of low velocity ports are located on the top surface of the burner tile for injecting the primary fuel-air mixture from the pre-mix region.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Provisional Application No. 62/310,015 filed Mar. 18, 2016, the contents of which are hereby incorporated by reference.

TECHNICAL FIELD

The technical field generally relates to an improved burner and burner method to provide a stable flame. More particularly, the technical field relates to a burner apparatus and method having an improved tile design to promote re-circulation of air and fuel for flame stabilization.

BACKGROUND

In the design of a thermal oxidizer, a stable burner flame is critical to the stability of the entire system. Instability of a thermal oxidizer's flame can cause a multitude of problems, including damaging vibrations, improper temperature readings and/or wall impingement due to fluctuating flame, and increased cost of operation due to excess air needed to stabilize the flame manually. Often times, this unstable flame occurs when the flame “lifts off” of the burner tile. This means that the flame is not properly anchored in the location in which it was designed. Improper flame anchoring occurs when the velocity of the air/fuel mixture intended for burning exceeds that particular fuel mixture's turbulent flame propagation speed, or the speed at which the mixture can burn and stay anchored to a surface.

Accordingly, it is desirable to provide methods and apparatuses for providing a stable burner flame in a thermal oxidizer. Further, it is desirable to provide an improved method and apparatus where air and fuel mixture has more time to mix and ignite to create a stable point at which the flame is anchored. Furthermore, other desirable features and characteristics of the present subject matter will become apparent from the subsequent detailed description of the subject matter and the appended claims, taken in conjunction with the accompanying drawings and this background of the subject matter.

BRIEF SUMMARY

Various embodiments contemplated herein relate to apparatuses and processes for providing a stable flame in a burner assembly. The exemplary embodiments taught herein include burner apparatus and method having an improved tile design to promote re-circulation of air and fuel for flame stabilization.

In accordance with an exemplary embodiment, a burner assembly is provided comprising a burner tile having a top surface, an outside surface, a pre-mix region and defining an interior space for introduction of combustion air. A plurality of primary fuel tips are disposed in the interior space for injection of a primary fuel followed by mixing of a portion of the primary fuel and a portion of the combustion air mix in the pre-mix region to provide a primary fuel-air mixture. A plurality of secondary fuel tips are located on the top surface or mounted near the outside surface of the burner tile. A plurality of low velocity ports are located on the top surface of the burner tile for injecting the primary fuel-air mixture from the pre-mix region.

In accordance with another exemplary embodiment, a burner assembly is provided comprising a burner tile having a top surface, an outside surface, a pre-mix region and defining an interior space for combustion air. A plurality of primary fuel tips are disposed in the interior space for injecting a primary fuel, wherein the pre-mix region is configured so that a portion of the primary fuel and a portion of the combustion air can mix to provide a primary fuel-air mixture. A plurality of secondary fuel tips are located on the top surface or mounted near the outside surface of the burner tile. A plurality of low velocity ports are located on the top surface of the burner tile for injecting the primary fuel-air mixture from the pre-mix region, the plurality of low velocity ports being present in a flame stabilizing lip incorporated into the burner tile, the flame stabilizing lip comprises a plurality of channels to provide the primary fuel-air mixture from the pre-mix region to a downstream end of burner tile, wherein each channel has a low velocity port, from the plurality of low velocity ports at the downstream end to inject the primary fuel-air mixture.

In accordance with yet another exemplary embodiment, a method is provided for obtaining a stable burner flame in a burner assembly comprising providing a primary fuel through a plurality of primary fuel tips into an interior space of the burner, the interior space being defined by a tile having a top surface, an outside surface and a pre-mix region. Combustion air is provided into the interior space, wherein a portion of the combustion air mixes with a portion of the primary fuel in the pre-mix region to provide a primary fuel-air mixture. A secondary fuel is provided through a plurality of secondary fuel tips located on the top surface or mounted near the outside surface of the burner tile. Further, a low-velocity primary fuel-air mixture is provided from the pre-mix region through a plurality of low velocity ports located on the top surface of the burner tile for injecting the air-fuel mixture.

BRIEF DESCRIPTION OF THE DRAWINGS

The various embodiments will hereinafter be described in conjunction with the following FIGURES, wherein like numerals denote like elements.

FIG. 1a illustrates an isometric view of the burner assembly in accordance with an exemplary embodiment of the instant invention.

FIG. 1b shows a sectional view taken along line 1-1 of FIG. 1a in accordance with an exemplary embodiment of the instant invention.

FIG. 1c shows a sectional isometric view taken along line 1-1 of FIG. 1a in accordance with an exemplary embodiment of the instant invention.

FIG. 2a illustrates an isometric view of the burner tile in accordance with an exemplary embodiment of the instant invention.

FIG. 2b illustrates a top view of the burner tile as shown in FIG. 2a in accordance with the instant exemplary embodiment of the instant invention.

FIG. 2c illustrates a sectional view of the burner tile taken along line 2-2 of FIG. 2a in accordance with the instant exemplary embodiment of the instant invention.

FIG. 2d illustrates a detailed section view of a portion of the burner tile between lines 3-3 and 3′-3 of FIG. 2c in accordance with the instant exemplary embodiment of the instant invention.

DETAILED DESCRIPTION

The following detailed description is merely exemplary in nature and is not intended to limit the various embodiments or the application and uses thereof. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.

An embodiment of a process and apparatus for providing a stable flame tip is addressed with reference to a burner assembly 100 as shown in FIG. 1. The burner assembly 100 may be mounted or otherwise fixed to an enclosed structure at a furnace wall, roof or floor (not shown) through a mounting plate. The burner assembly 100 may be in an environment of a floor of an enclosed structure, such as a furnace. Preferably, the burner assembly 100 may be used in a thermal oxidizer. Alternatively, burner assembly of the present invention may also be installed in a side wall or roof of any structure requiring heating with suitable modification which would be readily apparent to one of ordinary skill in the art having the present disclosure before them, without departing from the principles of the invention.

FIG. 1a illustrates an isometric view of the burner assembly 100 in accordance with an exemplary embodiment which includes a burner tile 102, a plurality of primary fuel tips 104, a plurality of secondary fuel tips 106, a plurality of low velocity ports 108, a combustion air inlet 110 and a combustion zone 112. The combustion air inlet 110 may be connected to an existing source of pre-heated combustion air. In accordance with an exemplary embodiment as shown in the instant FIGS. 1a-1c, the combustion zone 112 may include a primary combustion zone 112a and a secondary combustion zone 112b. FIG. 1b shows a sectional view taken along line 1-1 of the burner assembly 100 as shown in FIG. 1a, additionally illustrating a plenum chamber 114, a primary fuel manifold 116, a secondary fuel manifold 118, a plurality of primary fuel pipes 120 and a plurality of secondary fuel pipes 122. FIG. 1c shows a sectional isometric view taken along line 1-1 of the burner assembly 100 as shown in FIG. 1a. In accordance with an exemplary embodiment, during operation, combustion air is introduced into the plenum chamber 114 through combustion air inlet 110 and subsequently passed to the combustion zone 112. Accordingly, the combustion zone 112 may be in fluid communication with the plenum chamber 114 as discussed in detail with respect to FIGS. 2a-2d. The primary fuel manifold 116 may provide a primary fuel to the burner assembly 100. In accordance with an exemplary embodiment, the primary fuel manifold 116 feeds a plurality of primary fuel pipes 120 having the plurality of primary fuel tips 104 at a downstream end of the primary fuel pipe. Further, the secondary fuel manifold 118 provides the secondary fuel to the burner assembly 100. The secondary fuel manifold 118 may feed the plurality of second fuel pipes 122 having the plurality of secondary fuel tips 106 at a downstream end of the secondary fuel pipe. Fuel gas supplied to the burner assembly 100 may be split between the primary fuel tips 104 and secondary fuel tips 106 as the primary fuel and the secondary fuel. In accordance with an exemplary embodiment, at least 45% and preferably about 50% of the fuel is supplied to the primary fuel tips 104 and the balance through the secondary tips 106. Alternatively, the split in the fuel can be manipulated with a suitable control valve or with separate manifolds supplying fuel to each set of tips.

FIG. 2a illustrates an isometric view of the burner tile 102 in accordance with an exemplary embodiment of the instant invention. The burner tile 102 includes a top surface 202, an outside surface 204, a pre-mix region 206 and an interior space 208. As shown, the plurality of primary fuel tips 104 may be disposed in the interior space 208 of the burner tile for injection of the primary fuel from the primary fuel pipes 120. Further, the plurality of secondary fuel tips 106 may be located on the top surface of the burner tile 102. In an aspect, the plurality of secondary fuel tips 106 may be mounted near the outside surface of the burner tile. The plurality of secondary fuel tips 106 inject the secondary fuel from the secondary fuel pipes 122. During operation, a portion of the primary fuel injected through the plurality of primary fuel tips 104 and a portion of the combustion air introduced through the combustion air inlet 110 mix in the pre-mix region 206 to provide a primary fuel-air mixture. As shown, the plurality of low velocity ports 108 may be located on the top surface 202 of the burner tile for injecting at least a portion of the the primary fuel-air mixture from the pre-mix region 206. In accordance with an exemplary embodiment, the plurality of low velocity ports 108 may be present in a flame stabilizing lip 210 incorporated to the inside of the burner tile, as discussed with respect to FIG. 2d. The plurality of low velocity ports 108 may provide the may provide primary fuel-air mixture for combustion in the first combustion zone 112a and/or the second combustion zone 112b. Further, the secondary fuel tips 106 may provide secondary fuel for combustion in the first combustion zone 112a and/or the second combustion zone 112b. In accordance with an exemplary embodiment, the burner tile 102 may also have a plurality of recirculation conduits (not shown) located around the outside surface of the burner tile. recirculation conduits allow combustion product gases produced in the first and second combustion zones 112a and 112b and present within the enclosed structure to be recirculated from the outside surface of the tile 204 into the interior space 208 where it mixes with the a primary fuel-air mixture.

FIG. 2b illustrates a top view of the burner tile in accordance with the instant exemplary embodiment. FIG. 2c illustrates a sectional front view taken along line 2-2 of the burner tile 102 in accordance with the instant exemplary embodiment. FIG. 2d illustrates a detailed section view of a portion of the burner tile 102 between lines 3-3 and 3′-3 of FIG. 2c, in accordance with the instant exemplary embodiment of the instant invention showing a flame stabilizing lip 210. In various embodiments, burner tile 102 having the flame stabilizing lip 210 is made in the same way as conventional thermal oxidizer burner tiles and the flame stabilizing lip 210 may be a part of the actual refractory. Accordingly, mold geometry may only be modified in order to create the instant burner tile 102. In accordance with an exemplary embodiments, as shown in FIGS. 2a-2d, the flame stabilizing lip 210 may include a plurality of channels 212. In various embodiments, the plurality of channels 212 may be equally spaced along a circumference of the flame stabilizing lip 210. The plurality of channels 210 provide a restricted flow of a portion of the primary fuel-air mixture from the pre-mix region 206 to a downstream end of burner tile 102. In accordance with the exemplary embodiments as discussed, each channel has a low velocity port, from the plurality of low velocity ports 108, at the downstream end for injection of the primary fuel-air mixture into the combustion zone 112. The flame stabilizing lip 210 of the instant invention creates a low velocity zone in which the air and fuel mixture has more time to mix and ignite, creating a stable point at which a flame is anchored.

Although we have shown a preferred embodiment of our burner having a circular shaped title, the burner design could likewise be rectangular oval or square in shape. It will be understood that our invention may be embodied in other specific forms without departing from its spirit or central characteristics. The above-mentioned embodiments and figures, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given here.

Specific Embodiments

While the following is described in conjunction with specific embodiments, it will be understood that this description is intended to illustrate and not limit the scope of the preceding description and the appended claims.

A first embodiment of the invention is a burner assembly comprising a burner tile having a top surface, an outside surface, a pre-mix region and defining an interior space for introduction of combustion air; a plurality of primary fuel tips disposed in the interior space for injection of a primary fuel followed by mixing of a portion of the primary fuel and a portion of the combustion air mix in the pre-mix region to provide a primary fuel-air mixture; a plurality of secondary fuel tips located on the top surface or mounted near the outside surface of the burner tile; and a plurality of low velocity ports located on the top surface of the burner tile for injecting the primary fuel-air mixture from the pre-mix region. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph, wherein the plurality of low velocity ports are present in a flame stabilizing lip incorporated into the burner tile. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph, wherein the flame stabilizing lip comprises a plurality of equally spaced channels to provide a restricted flow of the primary fuel-air mixture from the pre-mix region to a downstream end of burner tile, wherein each channel has a low velocity port, from the plurality of low velocity ports, at the downstream end for injection of the primary fuel-air mixture. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising a plenum chamber having an inlet for introduction of the combustion air into the burner assembly. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising a combustion zone in fluid communication with the plenum chamber. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising a primary fuel manifold to provide the primary fuel to the burner assembly, the primary fuel manifold for feeding a plurality of primary fuel pipes having a primary fuel tip at a downstream end. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising a secondary fuel manifold for providing the secondary fuel to the burner assembly, the secondary fuel manifold feeding a plurality of second fuel pipes having a secondary fuel tip at a downstream end.

A second embodiment of the invention is a burner assembly comprising a burner tile having a top surface, an outside surface, a pre-mix region and defining an interior space for combustion air; a plurality of primary fuel tips disposed in the interior space for injecting a primary fuel, wherein the pre-mix region is configured so that a portion of the primary fuel and a portion of the combustion air can mix to provide a primary fuel-air mixture; a plurality of secondary fuel tips located on the top surface or mounted near the outside surface of the burner tile; and a plurality of low velocity ports located on the top surface of the burner tile for injecting the primary fuel-air mixture from the pre-mix region, the plurality of low velocity ports being present in a flame stabilizing lip incorporated into the burner tile, the flame stabilizing lip comprises a plurality of channels to provide the primary fuel-air mixture from the pre-mix region to a downstream end of burner tile, wherein each channel has a low velocity port, from the plurality of low velocity ports at the downstream end to inject the primary fuel-air mixture. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising a plenum chamber having an inlet for introduction of the combustion air into the burner assembly. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising a combustion zone in fluid communication with the plenum chamber. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising a primary fuel manifold to provide the primary fuel to the burner assembly, the primary fuel manifold for feeding a plurality of primary fuel pipes having a primary fuel tip at a downstream end. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising a secondary fuel manifold to provide the secondary fuel to the burner assembly, the secondary fuel manifold feeding a plurality of second fuel pipes having a secondary fuel tip at a downstream end. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph, wherein the plurality of channels are equally spaced along a circumference of the flame stabilizing lip.

A third embodiment of the invention is a method for obtaining a stable burner flame in a burner assembly, where the method comprises, providing a primary fuel through a plurality of primary fuel tips into an interior space of the burner, the interior space being defined by a tile having a top surface, an outside surface and a pre-mix region; providing combustion air into the interior space, wherein a portion of the combustion air mixes with a portion of the primary fuel in the pre-mix region to provide a primary fuel-air mixture; providing a secondary fuel through a plurality of secondary fuel tips located on the top surface or mounted near the outside surface of the burner tile; and providing a low-velocity primary fuel-air mixture from the pre-mix region through a plurality of low velocity ports located on the top surface of the burner tile for injecting the air-fuel mixture. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the third embodiment in this paragraph, wherein the plurality of low velocity ports are present in a flame stabilizing lip incorporated into the burner tile. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the third embodiment in this paragraph, wherein the flame stabilizing comprises a comprises a plurality of equally spaced channels to provide the primary fuel-air mixture from the pre-mix region to a downstream end of burner tile, wherein each channel has a low velocity port, from the plurality of low velocity ports, at the downstream end to inject the primary fuel-air mixture. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the third embodiment in this paragraph further comprising providing the combustion air to the burner assembly through a plenum chamber having an inlet. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the third embodiment in this paragraph further comprising providing the combustion air to the combustion zone from the plenum chamber. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the third embodiment in this paragraph further comprising providing the primary fuel to the burner assembly through a primary fuel manifold, the primary fuel manifold feeding a plurality of primary fuel pipes having a primary fuel tip at a downstream end. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the third embodiment in this paragraph further comprising providing the secondary fuel to the burner assembly through a secondary fuel manifold, the secondary fuel manifold feeding a plurality of second fuel pipes having a secondary fuel tip at a downstream end.

Without further elaboration, it is believed that using the preceding description that one skilled in the art can utilize the present invention to its fullest extent and easily ascertain the essential characteristics of this invention, without departing from the spirit and scope thereof, to make various changes and modifications of the invention and to adapt it to various usages and conditions. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limiting the remainder of the disclosure in any way whatsoever, and that it is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

In the foregoing, all temperatures are set forth in degrees Celsius and, all parts and percentages are by weight, unless otherwise indicated.

Claims

1. A burner assembly comprising:

(a) a burner tile having a top surface, an outside surface, a pre-mix region and defining an interior space for introduction of combustion air;

(b) a plurality of primary fuel tips disposed in the interior space for injection of a primary fuel followed by mixing of a portion of the primary fuel and a portion of the combustion air mix in the pre-mix region to provide a primary fuel-air mixture;

(c) a plurality of secondary fuel tips located on the top surface or mounted near the outside surface of the burner tile; and

(d) a plurality of low velocity ports located on the top surface of the burner tile for injecting the primary fuel-air mixture from the pre-mix region.

2. The burner assembly of claim 1, wherein the plurality of low velocity ports are present in a flame stabilizing lip incorporated into the burner tile.

3. The burner assembly of claim 2, wherein the flame stabilizing lip comprises a plurality of equally spaced channels to provide a restricted flow of the primary fuel-air mixture from the pre-mix region to a downstream end of the burner tile, wherein each channel has a low velocity port, from the plurality of low velocity ports, at the downstream end for injection of the primary fuel-air mixture.

4. The burner assembly of claim 1 further comprising a plenum chamber having an inlet for introduction of the combustion air into the burner assembly.

5. The burner assembly of claim 4 further comprising a combustion zone in fluid communication with the plenum chamber.

6. The burner assembly of claim 1 further comprising a primary fuel manifold to provide the primary fuel to the burner assembly, the primary fuel manifold for feeding a plurality of primary fuel pipes having a primary fuel tip at a downstream end.

7. The burner assembly of claim 1 further comprising a secondary fuel manifold for providing the secondary fuel to the burner assembly, the secondary fuel manifold feeding a plurality of second fuel pipes having a secondary fuel tip at a downstream end.

8. A burner assembly comprising:

(a) a burner tile having a top surface, an outside surface, a pre-mix region and defining an interior space for combustion air;

(b) a plurality of primary fuel tips disposed in the interior space for injecting a primary fuel, wherein the pre-mix region is configured so that a portion of the primary fuel and a portion of the combustion air can mix to provide a primary fuel-air mixture;

(c) a plurality of secondary fuel tips located on the top surface or mounted near the outside surface of the burner tile; and

(d) a plurality of low velocity ports located on the top surface of the burner tile for injecting the primary fuel-air mixture from the pre-mix region, the plurality of low velocity ports being present in a flame stabilizing lip incorporated into the burner tile, the flame stabilizing lip comprises a plurality of channels to provide the primary fuel-air mixture from the pre-mix region to a downstream end of burner tile, wherein each channel has a low velocity port, from the plurality of low velocity ports at the downstream end to inject the primary fuel-air mixture.

9. The burner assembly of claim 8 further comprising a plenum chamber having an inlet for introduction of the combustion air into the burner assembly.

10. The burner assembly of claim 9 further comprising a combustion zone in fluid communication with the plenum chamber.

11. The burner assembly of claim 8 further comprising a primary fuel manifold to provide the primary fuel to the burner assembly, the primary fuel manifold for feeding a plurality of primary fuel pipes having a primary fuel tip at a downstream end.

12. The burner assembly of claim 8 further comprising a secondary fuel manifold to provide the secondary fuel to the burner assembly, the secondary fuel manifold feeding a plurality of second fuel pipes having a secondary fuel tip at a downstream end.

13. The burner assembly of claim 8, wherein the plurality of channels are equally spaced along a circumference of the flame stabilizing lip.

14. A method for obtaining a stable burner flame in a burner assembly, where the method comprises:

(a) providing a primary fuel through a plurality of primary fuel tips into an interior space of the burner, the interior space being defined by a tile having a top surface, an outside surface and a pre-mix region;

(b) providing combustion air into the interior space, wherein a portion of the combustion air mixes with a portion of the primary fuel in the pre-mix region to provide a primary fuel-air mixture;

(c) providing a secondary fuel through a plurality of secondary fuel tips located on the top surface or mounted near the outside surface of the burner tile; and

(d) providing a low-velocity primary fuel-air mixture from the pre-mix region through a plurality of low velocity ports located on the top surface of the burner tile for injecting the air-fuel mixture.

15. The method of claim 14, wherein the plurality of low velocity ports are present in a flame stabilizing lip incorporated into the burner tile.

16. The method of claim 15, wherein the flame stabilizing comprises a comprises a plurality of equally spaced channels to provide the primary fuel-air mixture from the pre-mix region to a downstream end of burner tile, wherein each channel has a low velocity port, from the plurality of low velocity ports, at the downstream end to inject the primary fuel-air mixture.

17. The method of claim 14 further comprising providing the combustion air to the burner assembly through a plenum chamber having an inlet.

18. The method of claim 17 further comprising providing the combustion air to the combustion zone from the plenum chamber.

19. The method of claim 14 further comprising providing the primary fuel to the burner assembly through a primary fuel manifold, the primary fuel manifold feeding a plurality of primary fuel pipes having a primary fuel tip at a downstream end.

20. The method of claim 14 further comprising providing the secondary fuel to the burner assembly through a secondary fuel manifold, the secondary fuel manifold feeding a plurality of second fuel pipes having a secondary fuel tip at a downstream end.