Staged fuel burner

Abstract

The present invention discloses a liner for a staged fuel burner and a method of using a burner having the liner. The liner has a burner nozzle that injects a mixture of primary fuel and combustion air into a combustion zone to produce a flame. Staged fuel is also injected into the combustion zone. Before the staged fuel is injected from the burner nozzle into the combustion zone, the staged fuel is injected into the burner nozzle, and combustion air is drawn from a mixer of the burner liner into the burner nozzle having the staged fuel.

Description

Technical Field

[0001] The present invention generally relates to a premix burner for use in a furnace in a refinery or chemical processing plant, and more particularly to a liner for such a burner for producing a flame by burning a staged fuel. Background Art

[0002] In refineries and chemical processing plants, furnaces are used to provide heat to process fluids within conduits inside the furnace. Heat is generated in furnaces having radiant burners with nozzles that inject fuel / combustion air into the furnace to produce flames at the burner nozzles. An example of such a burner is shown in U.S. Pat. No. 9,194,579, the entire contents of which are incorporated herein.

[0003] In some conventional premixed staged fuel burners, the staged fuel flows through a center duct and is discharged into the combustion zone (inside the furnace) at the burner tip without being premixed with the combustion air. The primary fuel is mixed with the combustion air in the burner venturi and is also injected into the combustion zone at the burner tip. The primary fuel is separated from the staged fuel in the burner by the center duct.

[0004] In many conventional designs, the burner tip, and specifically the injection point of the staged fuel, is located within the furnace or otherwise positioned at a location that reaches very high temperatures due to thermal radiation from the furnace. The flow rate of the staged fuel through the center tube is insufficient to cool or otherwise reduce the temperature at the injection point. As a result, the high temperatures at the injection point may form coke deposits. This coke plugs the holes in the staged fuel tip, which is undesirable and negatively affects the effectiveness of the burner tip.

[0005] It would therefore be desirable to provide a burner tip that provides the benefits of using staged fuel injection but does not suffer from the disadvantages found in some conventionally used designs. Summary of the invention

[0006] A new premix liner for a burner and various methods associated therewith have been invented. According to various embodiments, combustion air is mixed with the staged fuel in the burner before the staged fuel is injected into the furnace. The addition of combustion air cools the staged fuel discharge holes, which reduces or eliminates the potential for coke formation and coke deposit fouling.

[0007] According to various aspects, the staged fuel outlet of the center tube is located inside the burner venturi / mixer to prevent overheating of the discharge orifice of the staged fuel. This also allows the staged fuel gas to mix with the combustion air before flowing through the burner nozzle and into the furnace. Due to the lower temperature, this mixture is less likely to form coke. In addition, the mixture of staged fuel and combustion air provides a higher mass flow rate, which will reduce the maximum temperature reached by the staged fuel before it is discharged into the furnace. The mixture of staged fuel and combustion air also reduces the temperature of the metal parts of the burner that contact the staged fuel.

[0008] Thus, in at least one aspect, the invention may be characterized by providing a liner for a staged fuel burner. The liner includes a mixer having an interior volume, a burner head having a body having an inner surface facing the interior volume of the mixer and an outer surface opposite the inner surface, and including a first plurality of exhaust holes communicating with the interior volume of the mixer, and a conduit extending within the mixer toward the burner head, the conduit terminating at a first end having an outlet spaced from the burner head so as to draw gas from the mixer to mix with fuel entering the burner head from the outlet.

[0009] It is contemplated that the conduit includes at least one injection hole spaced apart from the outlet and configured to provide fuel from the conduit to the interior volume of the mixer.

[0010] It is contemplated that the liner further comprises a second plurality of exhaust holes configured to receive fuel from the conduit. The exhaust holes in the second plurality of exhaust holes may be disposed on an uppermost portion of an outer surface of the burner nozzle. The exhaust holes in the first plurality of exhaust holes may be disposed on an outer sidewall of an outer surface of the burner nozzle.

[0011] The burner head is expected to include an inlet configured to receive fuel from an outlet of the conduit. The inlet of the burner head may be in communication with a second plurality of exhaust holes disposed on an outer surface of the burner head. The inlet of the burner head may include a guide wall extending into the mixer away from the body of the burner head. The outlet of the conduit may be disposed within the body of the burner head.

[0012] In a second aspect, the invention is generally characterized by providing a method for cooling a fuel conduit of a burner by: injecting fuel into a mixer of the burner; mixing the fuel with combustion air in the mixer to provide a primary fuel / air mixture; passing the primary fuel / air mixture through a first plurality of exhaust holes in a burner nozzle into a furnace containing a process fluid; combusting the primary fuel / air mixture in the furnace to produce a flame at the burner nozzle; passing a staged fuel through the mixer to the burner nozzle while separating the staged fuel from the primary fuel / air mixture in the mixer via a conduit; discharging the staged fuel from one end of the conduit into the burner nozzle; passing the staged fuel through a second plurality of exhaust holes in the burner nozzle; combusting the staged fuel in the furnace to produce a flame; and, cooling the end of the conduit by drawing gas from the mixer into the burner nozzle having the staged fuel.

[0013] The conduit may include at least one injection hole for injecting fuel into the mixer.

[0014] The exhaust holes of the second plurality of exhaust holes may be disposed on an uppermost portion of an outer surface of the burner head. The exhaust holes of the first plurality of exhaust holes may be disposed on an outer sidewall of an outer surface of the burner head.

[0015] The end of the conduit may include an outlet located within the body of the burner head.The body of the burner head may include an inlet for the conduit, and the inlet may include at least one guide wall.

[0016] In a third aspect, the invention is broadly characterized as providing a method for heating a process fluid with a burner by injecting a primary fuel into a mixer of the burner; mixing the primary fuel with combustion air in the mixer to provide a primary fuel / air mixture; passing the primary fuel / air mixture through a first plurality of exhaust holes in a burner nozzle into a furnace containing the process fluid; combusting the primary fuel / air mixture in the furnace to produce a flame at the burner nozzle, the flame providing heat to the process fluid; passing a staged fuel through the mixer to the burner nozzle while separating the staged fuel from the primary fuel / air mixture in the mixer in a conduit; discharging the staged fuel from the conduit toward the burner nozzle so as to draw gas from the mixer to mix with the staged fuel to provide a staged fuel / air mixture; passing the staged fuel / air mixture through a second plurality of exhaust holes in the burner nozzle into the furnace; and combusting the staged fuel to produce a flame.

[0017] The conduit may include an end having an outlet, and the staged fuel may be discharged from the conduit through the outlet. The burner head may include an inlet configured to receive the staged fuel discharged from the outlet. The inlet may include a guide wall.

[0018] The exhaust holes of the second plurality of exhaust holes may be disposed on an uppermost portion of an outer surface of the burner head, and the exhaust holes of the first plurality of exhaust holes may be disposed on an outer sidewall of the outer surface of the burner head.

[0019] Further aspects, embodiments and details of the invention (all of which may be combined in any manner) are set forth in the following detailed description of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] One or more exemplary embodiments of the present invention will be described below in conjunction with the following drawings, in which:

[0021] Figure 1 shows a cut-away side perspective view of a burner according to aspects of the present invention;

[0022] Figure 2 Shows Figure 1 A close-up perspective view of a portion of a burner in FIG.

[0023] Figure 3 Shows Figure 1 Another close-up perspective view of a portion of the burner in FIG.

[0024] Figure 4 Shows Figure 1 a side cross-sectional view of a burner nozzle of a burner; and,

[0025] Figure 5 Shows Figure 4 Top and side perspective views of a burner head.

[0026] In the several views of the accompanying drawings, corresponding reference numerals represent corresponding parts. It will be appreciated by the skilled person that the elements in the accompanying drawings are illustrated for simplicity and clarity and are not necessarily drawn to scale. For example, the sizes of some elements in the accompanying drawings may be exaggerated relative to other elements to help improve the understanding of the various embodiments of the present disclosure. Moreover, in order to facilitate less obstruction to the viewing of the various embodiments of the present disclosure, generally available or necessary and well-known elements in commercially feasible embodiments are not usually depicted. DETAILED DESCRIPTION

[0027] As described above, a new staged fuel burner has been invented. According to various embodiments, the staged fuel is mixed with the combustion air before being injected into the furnace. With these general principles in mind, one or more embodiments of the present invention will be described with the understanding that the following description is not intended to be limiting.

[0028] refer to Figure 1, the present invention relates to a premixing liner 10 for a burner, typically located in a burner brick or furnace wall. Such burners are known and are particularly suitable for cracking furnaces and reforming furnaces, but other furnaces are possible within the spirit and scope of the present invention. For an example of a furnace with a tube having a process fluid, reference is made to U.S. Patent Publication No. 2017 / 0003017, the entire contents of which are incorporated herein by reference.

[0029] The premixing liner 10 includes a burner tip 12 and a mixer 14. The mixer 14 has a body 16 having an interior volume 18. A conduit 20 extends through the interior volume 18 of the mixer. The conduit 20 has a first end 22 that terminates in an outlet 24 (also called a staged fuel tip) at the burner tip 12 (discussed in more detail below).

[0030] like Figure 2 As best shown, one or more injection holes 26 are spaced apart from the outlet 24 on the conduit 20. The injection holes 26 inject the primary fuel from the conduit 20 into the interior volume 18 of the mixer 14 to form a primary fuel / combustion air mixture with the air in the mixer 14.

[0031] return Figure 1 , the primary fuel / combustion air mixture passes through the mixer 14 toward the burner nozzle 12. At the same time, the remaining fuel in the duct 20, the staged fuel, also passes through the duct 20 toward the burner nozzle 12.

[0032] Steering Figure 3 , the burner head 12 includes a plurality of first exhaust holes 28 in communication with the interior volume 18 of the mixer 14. The primary fuel / combustion air mixture exits the burner at the burner head 12 via the first exhaust holes 28. After exiting the burner head 12, the primary fuel / combustion air mixture burns in the furnace to form a flame. As described above, the flame generates heat that is transferred to the process fluid in various conduits within the furnace.

[0033] The staged fuel exits the conduit 20 at the outlet 24 and enters the burner head 12. The outlet 24 is spaced from the burner head 12 so that the staged fuel draws combustion air from the mixer 14 to mix with the staged fuel as it enters the burner head 12. It should be understood that the combustion air mixed with the staged fuel will also include some primary fuel. As described above, by mixing the staged fuel with some combustion air, a better flame is produced, the outlet 24 is cooled by the gas flow, and is therefore less likely to overheat and form coke, plug, or otherwise damage the burner.

[0034] Steering Figure 4 , showing the outer surface 30 and the inner surface 32 of the burner nozzle 12. The inner surface 32 faces the inner volume 18 ( Figure 1 and Figure 3 ). The outer surface 30 is opposite to the inner surface 32 and is located entirely or partially in the furnace.

[0035] like Figure 4 and Figure 5 As shown, the outer surface 30 of the burner head 12 also includes a plurality of second exhaust holes 34 for injecting a staged fuel mixed with combustion air into the furnace to produce a flame. The plurality of exhaust holes 28 (for the primary fuel / combustion air mixture) are preferably located on a side wall 36 of the burner head 12. The side wall 36 has a height parallel to the longitudinal axis of the premixing liner 10 and has a thickness through which the first exhaust holes 28 extend. The plurality of second exhaust holes 34 (for the staged fuel) are preferably located on an uppermost portion 38 or top of the outer surface 30 of the burner head 12. The term "uppermost" refers to the orientation shown in the drawings, and it should be understood that the burner is not always arranged in an uppermost direction. Figure 4 Use in the configuration or orientation shown in .

[0036] like Figure 4 As shown, the burner head 12 includes an inlet 40 on the inner surface 32 for receiving fuel from the outlet 24 of the duct 20. The inlet 40 communicates with the plurality of exhaust holes 34 via a flow passage 42 within the burner head 12.

[0037] In the depicted embodiment, the conduit 20 extends at least to the inlet 40, but does not extend to the uppermost portion 38 of the outer surface 30. The conduit 20 may extend partially into the body 44 of the burner head 12 so that the outlet 24 is located within the body 44 of the burner head 12. However, it is also contemplated that the outlet 24 is located slightly below the inlet 40. As described above, when the staged fuel exits the outlet 24, the interior volume 18 ( Figure 1 and Figure 3 ) will be drawn into the inlet 40, mixed with the staged fuel, passed through the passage 42, and injected into the furnace via the second exhaust hole 34. Thus, the conduit 20 and the body 44 of the burner head 12 are spaced apart and not in contact. However, other configurations and arrangements may be used so that air from the mixer 14 is drawn into the burner head 12 to mix with the staged fuel. For example, although not shown, the holes should be included on the inner surface 32 so that the combustion air is drawn into the plenum within the body 44, which also receives the staged fuel.

[0038] exist Figure 4 In the embodiment, the inlet 40 includes one or more guide walls 46 ( Figure 1 and Figure 3The primary purpose of the guide wall 46 is to center the conduit 20, and more specifically, to ensure that the first end 22 is properly positioned, which is generally centered relative to the body 44 of the burner head 12. Additionally, depending on shape and size, the guide wall 46 may also control or direct the flow of air and fuel into the inlet 40.

[0039] Thus, by utilizing the premix liner 10 of the present invention in a burner, the benefits of using a staged fuel burner are realized while reducing the risk of coking at the burner tip due to overheating.

[0040] Those of ordinary skill in the art will recognize and appreciate that various other components such as valves, pumps, filters, coolers, etc. are not shown in the accompanying drawings because it is believed that their details are well within the knowledge of those of ordinary skill in the art and their description is not necessary for the practice or understanding of the embodiments of the present invention.

[0041] Any of the above-mentioned pipelines, conduits, units, equipment, containers, surrounding environments, zones, or the like may be equipped with one or more monitoring components, including sensors, measuring devices, data capture devices, or data transmission devices. Signals, process or state measurements and data from the monitoring components can be used to monitor conditions in, around, and related to the process equipment. The signals, measurements, and / or data generated or recorded by the monitoring components can be collected, processed, and / or transmitted via one or more networks or connections, which can be private or public, general or dedicated, direct or indirect, wired or wireless, encrypted or unencrypted, and / or combinations thereof; the present specification is not intended to be limiting in this regard.

[0042] The signals, measurements, and / or data generated or recorded by the monitoring components may be transmitted to one or more computing devices or systems. The computing device or system may include at least one processor and a memory storing computer-readable instructions that, when executed by at least one processor, cause one or more computing devices to perform a method that may include one or more steps. For example, one or more computing devices may be configured to receive data related to at least one piece of equipment associated with the method from one or more monitoring components. One or more computing devices or systems may be configured to analyze the data. Based on the data analysis, one or more computing devices or systems may be configured to determine one or more recommended adjustments to one or more parameters of one or more methods described herein. One or more computing devices or systems may be configured to transmit encrypted or unencrypted data, which includes one or more recommended adjustments to one or more parameters of one or more methods described herein.

[0043] Specific implementation plan

[0044] While the following is described in conjunction with specific embodiments, it should be understood that this description is intended to illustrate and not to limit the scope of the foregoing description and the appended claims.

[0045] A first embodiment of the invention is a liner for a staged fuel burner, the liner comprising a mixer having an interior volume; a burner head comprising a body having an inner surface facing the interior volume of the mixer and an outer surface opposite the inner surface, the outer surface of the burner head comprising a first plurality of exhaust holes, wherein the exhaust holes in the first plurality of exhaust holes are in communication with the interior volume of the mixer; and a conduit extending within the mixer toward the burner head, the conduit terminating at a first end having an outlet spaced from the burner head so as to extract gas from the mixer to mix with fuel entering the burner head from the outlet. An embodiment of the invention is one, any or all of the previous embodiments of this paragraph to the first embodiment of this paragraph, wherein the conduit comprises at least one injection hole spaced from the outlet and configured to provide fuel from the conduit to the interior volume of the mixer. An embodiment of the invention is one, any or all of the previous embodiments of this paragraph to the first embodiment of this paragraph, and further comprises a second plurality of exhaust holes configured to receive fuel from the conduit. One embodiment of the present invention is one, any or all of the previous embodiments of this paragraph to the first embodiment of this paragraph, wherein the exhaust holes in the second plurality of exhaust holes are arranged on the uppermost part of the outer surface of the burner nozzle head. One embodiment of the present invention is one, any or all of the previous embodiments of this paragraph to the first embodiment of this paragraph, wherein the exhaust holes in the first plurality of exhaust holes are arranged on the outer side wall of the outer surface of the burner nozzle head. One embodiment of the present invention is one, any or all of the previous embodiments of this paragraph to the first embodiment of this paragraph, wherein the burner nozzle includes an inlet configured to receive fuel from the outlet of the conduit. One embodiment of the present invention is one, any or all of the previous embodiments of this paragraph to the first embodiment of this paragraph, wherein the inlet of the burner nozzle is connected to the second plurality of exhaust holes arranged on the outer surface of the burner nozzle. One embodiment of the present invention is one, any or all of the previous embodiments of this paragraph to the first embodiment of this paragraph, wherein the inlet of the burner nozzle includes a guide wall extending away from the body of the burner nozzle into the mixer. An embodiment of the present invention is one, any or all of the prior embodiments in this paragraph through the first embodiment in this paragraph wherein the outlet of the conduit is disposed within the body of the burner head.

[0046] A second embodiment of the invention is a method for cooling a fuel conduit of a burner, the method comprising injecting fuel into a mixer of the burner; mixing the fuel with combustion air in the mixer to provide a primary fuel / air mixture; passing the primary fuel / air mixture through a first plurality of exhaust holes on a burner nozzle into a furnace containing a process fluid; burning the primary fuel / air mixture in the furnace to produce a flame at the burner nozzle; passing a staged fuel through the mixer to the burner nozzle while separating the staged fuel from the primary fuel / air mixture in the mixer via a conduit; discharging the staged fuel from one end of the conduit into the burner nozzle; passing the staged fuel through a second plurality of exhaust holes on the burner nozzle; burning the staged fuel in the furnace to produce a flame; and cooling the end of the conduit by drawing gas from the mixer into the burner nozzle having the staged fuel. An embodiment of the invention is one, any or all of the previous embodiments of this paragraph to the second embodiment of this paragraph, wherein the conduit includes at least one injection hole for injecting fuel into the mixer. One embodiment of the present invention is one, any one or all of the previous embodiments of this paragraph to the second embodiment of this paragraph, wherein the exhaust holes in the second plurality of exhaust holes are arranged on the uppermost portion of the outer surface of the burner nozzle head. One embodiment of the present invention is one, any one or all of the previous embodiments of this paragraph to the second embodiment of this paragraph, wherein the exhaust holes in the first plurality of exhaust holes are arranged on the outer side wall of the outer surface of the burner nozzle head. One embodiment of the present invention is one, any one or all of the previous embodiments of this paragraph to the second embodiment of this paragraph, wherein the end of the conduit includes an outlet located in the body of the burner nozzle head. One embodiment of the present invention is one, any one or all of the previous embodiments of this paragraph to the second embodiment of this paragraph, wherein the body of the burner nozzle head includes an inlet for the conduit, and wherein the inlet includes at least one guide wall.

[0047] A third embodiment of the present invention is a method for heating a process fluid with a burner, the method comprising injecting a primary fuel into a mixer of the burner; mixing the primary fuel with combustion air in the mixer to provide a primary fuel / air mixture; passing the primary fuel / air mixture through a first plurality of exhaust holes on a burner nozzle into a furnace containing the process fluid; burning the primary fuel / air mixture in the furnace to produce a flame at the burner nozzle, the flame providing heat to the process fluid; passing a staged fuel through the mixer to the burner nozzle, while separating the staged fuel from the primary fuel / air mixture in the mixer in a conduit; discharging the staged fuel from the conduit toward the burner nozzle so as to draw gas from the mixer to mix with the staged fuel to provide a staged fuel / air mixture; passing the staged fuel / air mixture through a second plurality of exhaust holes on the burner nozzle into the furnace; and burning the staged fuel to produce a flame. An embodiment of the present invention is one, any or all of the previous embodiments of this paragraph to the third embodiment of this paragraph, wherein the conduit includes an end having an outlet, wherein the staged fuel is discharged from the conduit through the outlet. One embodiment of the present invention is one, any or all of the previous embodiments of this paragraph to the third embodiment of this paragraph, wherein the burner nozzle includes an inlet configured to receive the staged fuel discharged from the outlet. One embodiment of the present invention is one, any or all of the previous embodiments of this paragraph to the third embodiment of this paragraph, wherein the inlet includes a guide wall. One embodiment of the present invention is one, any or all of the previous embodiments of this paragraph to the third embodiment of this paragraph, wherein the exhaust holes in the second plurality of exhaust holes are arranged on the uppermost portion of the outer surface of the burner nozzle head, and wherein the exhaust holes in the first plurality of exhaust holes are arranged on the outer side wall of the outer surface of the burner nozzle head.

[0048] Although there is no further detailed description, it is believed that those skilled in the art can utilize the present invention to the greatest extent by using the foregoing description and can easily determine the essential characteristics of the present invention without departing from the spirit and scope of the present invention to make various changes and modifications of the present invention and adapt it to various usages and conditions. Therefore, the aforementioned preferred specific embodiments should be understood as merely illustrative and not to limit the rest of the present disclosure in any way, and are intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

[0049] Although at least one exemplary embodiment has been presented in the foregoing specific embodiments of the present invention, it should be understood that there are a large number of variations. It should also be understood that an exemplary embodiment or multiple exemplary embodiments are only examples and are not intended to limit the scope, applicability or configuration of the present invention in any way. On the contrary, the foregoing specific embodiments will provide a convenient roadmap for those skilled in the art to implement the exemplary embodiments of the present invention, and it should be understood that various changes can be made to the functions and arrangements of the elements described in the exemplary embodiments without departing from the scope of the present invention as set forth in the attached claims and their legal equivalents.

Claims

1. A liner (10) for a staged fuel burner, the liner (10) comprising: a mixer (14) having an interior volume (18); A burner nozzle (12), the burner nozzle comprising a body (44) having an inner surface (32) facing the inner volume (18) of the mixer (14) and an outer surface (30) opposite the inner surface (32), the outer surface (30) of the burner nozzle (12) comprising a plurality of first exhaust holes (28), wherein the first exhaust holes (28) are in communication with the inner volume (18) of the mixer (14); a conduit (20) extending within the mixer (14) toward the burner head (12), the conduit (20) terminating at a first end (22) having an outlet (24) spaced from the burner head (12) for drawing gas from the mixer (14) to mix with fuel entering the burner head (12) from the outlet (24); and a plurality of second exhaust ports (34) configured to receive the fuel from the conduit (20); wherein the second exhaust hole (34) is disposed on the uppermost portion (38) of the outer surface (30) of the burner nozzle (12), The outlet (24) of the conduit (20) is disposed within the body (44) of the burner head (12).

2. The liner (10) of claim 1, wherein the conduit (20) includes at least one injection hole (26) spaced apart from the outlet (24) and configured to provide fuel from the conduit (20) to the interior volume (18) of the mixer (14).

3. The liner (10) according to claim 1, wherein the first exhaust hole (28) is disposed on an outer side wall of the outer surface (30) of the burner nozzle (12).

4. The liner (10) according to any one of claims 1 to 3, wherein the burner head (12) includes an inlet (40) configured to receive fuel from the outlet (24) of the conduit (20).

5. The liner (10) according to any one of claims 1 to 3, wherein the burner head (12) includes a guide wall (46) extending away from the body (44) of the burner head (12) into the mixer (14).

6. A method for cooling a fuel conduit (20) of a burner, the method comprising: injecting fuel into a mixer (14) of the burner; mixing the fuel with combustion air in the mixer (14) to provide a primary fuel / air mixture; allowing the primary fuel / air mixture to enter a furnace containing a process fluid through a plurality of first exhaust ports (28) in a burner nozzle (12); burning the primary fuel / air mixture in the furnace to produce a flame at the burner tip (12); passing a staged fuel through the mixer (14) to the burner tip (12) while separating the staged fuel from the primary fuel / air mixture in the mixer (14) via the conduit (20); Discharging the graded fuel from one end of the conduit (20) into the burner nozzle (12); passing the staged fuel through a plurality of second exhaust holes (34) on the burner tip (12), wherein the plurality of second exhaust holes (34) are configured to receive the staged fuel from the conduit (20), and wherein the second exhaust holes (34) are disposed on an uppermost portion (38) of an outer surface (30) of the burner tip (12); burning the staged fuel in the furnace to produce the flame; and, cooling the end of the conduit (20) by drawing gas from the mixer (14) into the burner head (12) with the staged fuel, The end of the conduit (20) includes an outlet (24) located within a body (44) of the burner head (12).

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