REFRACTORY BLOCK FOR LOW NOX BURNERS WITH INTERNAL FLUE GAS RECIRCULATION

Abstract

A refractory apparatus may include a refractory bock comprising a heat shield. The refractory block can include a group of flue gas ports that acts as a gateway for flue gas produced due to combustion downstream of a burner. A suction created in the burner drives the flue gas into the burner through the flue gas ports. A group of staged risers can be housed within the refractory block. The staged risers are protected in staged fuel riser housings in the refractory block. A discharge cone is located in the refractory block for flame stabilization in the burner.

Claims

1. A refractory apparatus, comprising: a refractory bock comprising a heat shield, wherein the refractory block includes a plurality of flue gas ports that acts as a gateway for flue gas produced due to combustion downstream of a burner, wherein a suction created in the burner drives the flue gas into the burner through the plurality of flue gas ports; a plurality of staged risers housed within the refractory block, wherein the plurality of staged risers is protected in staged fuel riser housings in the refractory block; and a discharge cone located in the refractory block for flame stabilization in the burner.

2. The refractory apparatus of claim 1 wherein the plurality of flue gas ports comprise angles that vary from 0 to 90 degrees.

3. The refractory apparatus of claim 1 wherein the refractory block comprises a refractory material configured on aluminum and silicon oxides with a temperature rating greater than 2600 F.

4. The refractory apparatus of claim 1 wherein each flue gas port among the plurality of flue gas ports includes a slot having a slot area selected to obtain flue gas up to 20% of combustion air.

5. The refractory apparatus of claim 4 wherein the slot comprises a shape that is at least one of: circular or rectangular with curved edges.

6. The refractory apparatus of claim 1 further comprising a flange connected to the refractory block.

7. The refractory apparatus of claim 1 wherein each staged riser among the plurality of staged rises comprises stainless steel.

8. The refractory apparatus of claim 1 wherein the plurality of flue gas ports include a number of flue gas ports ranging from four flue gas ports to twelve flue gas ports.

9. A refractory apparatus, comprising: a refractory bock comprising a heat shield, wherein the refractory block includes a plurality of flue gas ports that acts as a gateway for flue gas produced due to combustion downstream of a burner, wherein a suction created in the burner drives the flue gas into the burner through the plurality of flue gas ports, wherein the plurality of flue gas ports comprise angles that vary from 0 to 90 degrees; a plurality of staged risers housed within the refractory block, wherein the plurality of staged risers is protected in staged fuel riser housings in the refractory block; and a discharge cone located in the refractory block for flame stabilization in the burner.

10. The refractory apparatus of claim 9 wherein the refractory block comprises a refractory material configured on aluminum and silicon oxides with a temperature rating greater than 2600 F.

11. The refractory apparatus of claim 9 wherein each flue gas port among the plurality of flue gas ports includes a slot having a slot area selected to obtain flue gas up to 20% of combustion air.

12. The refractory apparatus of claim 11 wherein the slot comprises a shape that is at least one of: circular or rectangular with curved edges.

13. The refractory apparatus of claim 9 further comprising a flange connected to the refractory block.

14. The refractory apparatus of claim 9 wherein each staged riser among the plurality of staged rises comprises stainless steel.

15. The refractory apparatus of claim 9 wherein the plurality of flue gas ports include a number of flue gas ports ranging from four flue gas ports to twelve flue gas ports.

16. A method of operating a refractory apparatus, comprising: providing a refractory bock comprising a heat shield, wherein the refractory block includes a plurality of flue gas ports that act as a gateway for flue gas produced due to combustion downstream of a burner, wherein a suction created in the burner drives the flue gas into the burner through the plurality of flue gas ports; protecting a plurality of staged risers housed within the refractory block with staged fuel riser housings in the refractory block; and stabilizing a flame with respect to the flue gas in a discharge cone located in the refractory block, wherein the discharge cone facilitates flame stabilization in the burner.

17. The method of claim 16 wherein the plurality of flue gas ports comprise angles that vary from 0 to 90 degrees.

18. The method of claim 17 wherein the refractory block comprises a refractory material configured on aluminum and silicon oxides with a temperature rating greater than 2600 F.

19. The method of claim 18 wherein each flue gas port among the plurality of flue gas ports includes a slot having a slot area selected to obtain flue gas up to 20% of combustion air.

20. The method of claim 4 wherein the slot comprises a shape that is at least one of: circular or rectangular with curved edges.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying figures, in which like reference numerals refer to identical or functionally similar elements throughout the separate views and which are incorporated in and form a part of the specification, further illustrate the present invention and, together with the detailed description of the invention, serve to explain the principles of the present invention.

[0022] FIG. 1 illustrates a cut-away perspective view of a burner and associated burner components, in accordance with an embodiment;

[0023] FIG. 2 illustrates a side sectional view of the burner shown in FIG. 1 including the Internal Flue Gas Recirculation (IFGR) path, in accordance with an embodiment;

[0024] FIG. 3 illustrates a perspective view of a refractory apparatus for use with the burner shown in FIG. 1 and FIG. 2, in accordance with an embodiment;

[0025] FIG. 4 illustrates a cut-sectional view of the refractory apparatus shown in FIG. 3, in accordance with an embodiment;

[0026] FIG. 5 illustrates a cut-away perspective view of a burner and associated burner components, in accordance with an alternative embodiment; and

[0027] FIG. 6 illustrates a cut-away perspective view of a burner and associated burner components, in accordance with yet another embodiment.

[0028] Identical or similar parts or elements in the figures are indicated by the same reference numerals.

DETAILED DESCRIPTION

[0029] The particular values and configurations discussed in these non-limiting examples can be varied and are cited merely to illustrate one or more embodiments and are not intended to limit the scope thereof.

[0030] Subject matter will now be described more fully hereinafter with reference to the accompanying drawings, which form a part hereof, and which show, by way of illustration, specific example embodiments. Subject matter may, however, be embodied in a variety of different forms and, therefore, covered or claimed subject matter is intended to be construed as not being limited to any example embodiments set forth herein; example embodiments are provided merely to be illustrative. Likewise, a reasonably broad scope for claimed or covered subject matter is intended. Among other issues, subject matter may be embodied as methods, devices, components, or systems. Accordingly, embodiments may, for example, take the form of hardware, software, firmware, or a combination thereof. The following detailed description is, therefore, not intended to be interpreted in a limiting sense.

[0031] Throughout the specification and claims, terms may have nuanced meanings suggested or implied in context beyond an explicitly stated meaning. Likewise, phrases such as in an embodiment or in one embodiment or in an example embodiment and variations thereof as utilized herein may or may not necessarily refer to the same embodiment and the phrase in another embodiment or in another example embodiment and variations thereof as utilized herein may or may not necessarily refer to a different embodiment. It is intended, for example, that claimed subject matter include combinations of example embodiments in whole or in part.

[0032] In general, terminology may be understood, at least in part, from usage in context. For example, terms such as and, or, or and/or as used herein may include a variety of meanings that may depend, at least in part, upon the context in which such terms are used. Generally, or if used to associate a list, such as A, B, or C, is intended to mean A, B, and C, here used in the inclusive sense, as well as A, B, or C, here used in the exclusive sense. In addition, the term one or more as used herein, depending at least in part upon context, may be used to describe any feature, structure, or characteristic in a singular sense or may be used to describe combinations of features, structures, or characteristics in a plural sense. Similarly, terms such as a, an, or the, again, may be understood to convey a singular usage or to convey a plural usage, depending at least in part upon context. Furthermore, the term at least one as used herein, may refer to one or more. For example, at least one widget may refer to one or more widgets.

[0033] In addition, the term based on may be understood as not necessarily intended to convey an exclusive set of factors and may, instead, allow for existence of additional factors not necessarily expressly described, again, depending at least in part on context.

[0034] FIG. 1 illustrates a cut-away perspective view of a burner 100, in accordance with an embodiment. The burner 100 can be implemented as an ultra-low NOx (ULE) burner 100 that uses Internal Flue Gas Recirculation (IFGR). FIG. 1 depicts the burner major components of the burner 100 including, for example, a cylindrically shaped housing 102 maintains components such as a jet pump 108, an Flue Gas Recirculation (FGR) tube 110, and a mixing tube 112. A fuel inlet 105 can be partially surrounded by the jet pump 108 and the mixing tube 112.

[0035] The ultra-low NOx burner 100 can manage and optimize fuel and air mixing, which can occur inside, for example, the burner 100 and/or other devices such as a boiler. As the process is optimized, a large and much more balanced flame can be created, which can reduce the peak temperature and therefore a minimal amount of NOx may be produced.

[0036] The burner 100 can further include a combustion air inlet 107 surrounded by a circular flange 104 located to the left of a burner flange 106. The right portion of the burner 100 can include one or more FGR ports such as FGR port 120, FGR port 122, etc., along with a refractory block 116 and a torpedo assembly 118.

[0037] In the burner 100, flue gas can be pulled into the burner 100 with the jet pump 108, which can act like a suction pump. The flue gas can be pulled into the burner from flue gas ports that are incorporated into a refractory block 116 and a burner flange 106. The flue gas mixes with the air stream in a mixing zone. The flame can be stabilized at the end of the burner 100 in a discharge cone. In the burner 100, less than, for example, 25 ppm NOx may be achieved.

[0038] In order for this IFGR technology to function properly, the flue gas has to be pulled from a combustion chamber and then mixed with the incoming air stream. In the embodiments, the flue gas can be pulled from a burner head configured from the refractory block 116. This configuration can require a careful design of the refractory block 116, which can also act as a discharge cone and can house second stage risers.

[0039] FIG. 2 illustrates a side sectional view of the burner 100 shown in FIG. 1 including a Flue Gas Recirculation (FGR) path, in accordance with an embodiment. The FGR path is depicted in FIG. 2 by the path of the arrows depicted therein. FIG. 2 demonstrates the design of the burner 100 with the flow path of flue gas recirculation and the role of the refractory block 116. The refractory block is an important component of the burner 100. The refractory block can solve four issues including: 1) the refractory block has flue gas ports (e.g., FGR ports 120, 122, etc.), which can be used to recirculate the flue gas into the burner 100; 2) the refractory block can serve to house the fuel staging risers; 3) the refractory block can act as a heat shield for the burner flange 106; and 4) the refractory block can act as a discharge cone 132 for the burner 100. As shown in FIG. 2, a refractory apparatus 130 can generally include or encompass the refractory block 116, the FGR block 104, and the FGR inlet ports 120, 122, etc.

[0040] FIG. 3 illustrates a perspective view of the refractory apparatus 130 including the refractory block 116 of the burner 100 shown in FIG. 1 and FIG. 2, in accordance with an embodiment. The refractory apparatus 130 can function as a heat shield. The refractory block 116 can include a group of flue gas ports that can function as a gateway for flue gas produced due to combustion downstream of the burner 100. A suction created in the burner 100 can drive the flue gas into the burner 100 through the flue gas ports. A group of staged risers can be housed within the refractory block 116. The staged risers are protected in staged fuel riser housings in the refractory block 116. The discharge cone 132 can be located in the refractory block 116 for flame stabilization in the burner 100.

[0041] The refractory block 116 can be configured with refractory material composed on aluminum and silicon oxides with a temperature rating of greater than, for example, 2600 F. The refractory block 116 can be configured with several flue gas ports ranging to 4-12. The slots can be either circular or rectangular with curved edges. The slot angle can vary between 0 to 90 degrees. The slot area may be selected to attain flue gas up to, for example, 20% of the combustion air. The flue gas ports are the gateway for the flue gas that can be produced due to the combustion downstream of the burner 100. The suction created in the burner 100 can drive the flue gas into the burner 100 through the flue gas ports. The refractory block 116 also houses the staged rises. The staged risers can be configured from stainless steel. The risers are protected in the staged fuel riser housings in the refractory block 116.

[0042] FIG. 4 illustrates a cut-sectional view of the refractory apparatus 130 shown in FIG. 3, in accordance with an embodiment. The refractory block 116 can also incorporate the discharge cone 132 for flame stabilization. The embodiments can reduce the NO.sub.x up to 50% than without the FGR ports and riser housing.

[0043] The burner 100 can be implemented, for example, in the context of fired process heaters and boilers. The burner 100 offers a novel torpedo design with the refractory 100 and/or the refractory block 116 as a key component of the ULE burner 100. This is a novel design where a single component of the ULE burner 100 can solve the aforementioned issues of a) internal flue gas recirculation; b) flame stabilization; c) staged risers; and d) heat shield. The ULE burner 100 can reduce NO.sub.x up to 50% from indirect fired burners and with a turn-down ratio of 10:1. This method of internal flue gas recirculation is unique and consolidates a ULE burner design for low NOx of less than 25 ppm. There are presently no burners that can effectively produce very low NOx in indirect fired process heaters and boilers with IFGR. The disclosed embodiments can eliminate external flue gas recirculation piping and high temperature blowers and can also be scaled to larger burner sizes.

[0044] The refractory block 116 can be cast on a stainless-steel flange with a sleeve. The studs can be welded to the stainless steel flange and then refractory material can be poured into the mold made for each block size. The casting can be allowed to rest for 24-28 hours until the cast is set. The refractory block 116 can be prefixed at a low temperature for 4-6 hours, for example, to allow for sufficient time for the cast to harden and remove the moisture in the cast. The number of FGR slots and the riser housing ports may be selected based on the burner size and NOx requirements.

[0045] The refractory block 110 can be used in, for example, the ULE-Burner series of burner products from Honeywell International Inc., or may be implemented in other burner products, designs and burner systems. The burner sizes may range from, for example, 2.5 MMBTU/hr to 50 MMBTU/hr. Each burner will have a refractory block installed. This component of the burner 100 may be critical for the functioning of the burner 100. The burner 100 and related components can be installed in indirect fired systems such as process heaters and boilers.

[0046] FIG. 5 illustrates a cut-away perspective view of a burner 101 and associated burner components, in accordance with an alternative embodiment. The burner 101 shown in FIG. 5 is similar to the previously described burner 100 albeit with a different design. The burner 101 includes similar components such as the refractory block 116, inlet ports such as inlet port 120, the combustion air inlet 107, the FGR tube 110, the jet pump 108, and the mixing tube 112. The torpedo assembly 118 is shown in FIG. 5 in the context of a different burner design.

[0047] FIG. 6 illustrates a cut-away perspective view of a burner 103 and associated burner components, in accordance with yet another embodiment. The burner 103 shown in FIG. 5 is similar to the previously described burner 100 and burner 101, albeit with a variation to the design of the FGR inlet ports. That is, the burner 103 can include many of the same components as the other burners 100, 101, but with a different design configuration. In the configuration shown in FIG. 6, the FGR inlet ports are shown as 90? inlet port(s) 121. That is, the design of burner 103 incorporates variation of the refractory block 116 where the angle is 90 degrees.

[0048] Based on the foregoing, it can be appreciated that a number of embodiments are disclosed herein. For example, in an embodiment, a refractory apparatus 130 may include the refractory bock 116 which can function as or comprise a heat shield. The refractory block 116 can include a group of flue gas ports that can act as a gateway for the flue gas produced due to combustion downstream of the burner 100, 101. A suction created in the burner 100, 101 can drive the flue gas into the burner 100, 101 through the group of flue gas ports. Furthermore, staged risers can be housed within the refractory block 116. The staged risers can be protected in staged fuel riser housings in the refractory block 116. The discharge cone 132 can be located in the refractory block 116 for flame stabilization in the burner.

[0049] In an embodiment of the refractory apparatus 130, the plurality of flue gas ports can comprise angles that vary from 0 to 90 degrees.

[0050] In an embodiment of the refractory apparatus 130, the refractory block can comprise a refractory material configured on aluminum and silicon oxides with a temperature rating greater than, for example, 2600 F.

[0051] In an embodiment of the refractory apparatus 130, each flue gas port among the plurality of flue gas ports can include or be configured with a slot having a slot area selected to obtain flue gas up to, for example, 20% of combustion air.

[0052] In an embodiment of the refractory apparatus 130, a slot can be configured with a shape that is circular or rectangular with curved edges.

[0053] In an embodiment of the refractory apparatus 130, a flange can be connected to the refractory block.

[0054] In an embodiment of the refractory apparatus 130, each staged riser among the plurality of staged rises can comprise stainless steel.

[0055] In an embodiment of the refractory apparatus 130, the plurality of flue gas ports can include a number of flue gas ports ranging from four flue gas ports to twelve flue gas ports.

[0056] In another embodiment, the refractory apparatus 130 can include a refractory bock comprising a heat shield, wherein the refractory block includes a plurality of flue gas ports that acts as a gateway for flue gas produced due to combustion downstream of a burner, wherein a suction created in the burner drives the flue gas into the burner through the plurality of flue gas ports, wherein the plurality of flue gas ports comprise angles that vary from 0 to 90 degrees a plurality of staged risers housed within the refractory block, wherein the plurality of staged risers is protected in staged fuel riser housings in the refractory block; and a discharge cone located in the refractory block for flame stabilization in the burner.

[0057] In yet another embodiment, a method of operating a refractory apparatus 130, can involve: providing a refractory bock comprising a heat shield, wherein the refractory block includes a plurality of flue gas ports that acts as a gateway for flue gas produced due to combustion downstream of a burner, wherein a suction created in the burner drives the flue gas into the burner through the plurality of flue gas ports; protecting a plurality of staged risers housed within the refractory block with staged fuel riser housings in the refractory block; and stabilizing a flame with respect to the flue gas in a discharge cone located in the refractory block, wherein the discharge cone facilitates flame stabilization in the burner.

[0058] It will be appreciated that variations of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. It will also be appreciated that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.