Fuel nozzle for use in industrial combustion systems

Abstract

A fuel nozzle design suitable for use in industrial combustion systems and exhibiting reduced fouling and coking is disclosed. The fuel nozzle has a fuel inlet, a bore, and an outlet port. The fuel nozzle design provides improved mixing of fuel flow through the nozzle bore and pressure drop at the nozzle outlet.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit under 35 U.S.C. Section 119(e) of U.S. patent application Ser. No. 63 / 478,701, filed Jan. 6, 2023, and U.S. patent application Ser. No. 63 / 522,438, filed Jun. 22, 2023, the entire disclosures of both of which are incorporated herein by reference.

[0002] FIELD OF THE INVENTION FIELD OF THE DISCLOSURE The present disclosure relates to the field of combustion, and more particularly, but not exclusively, to industrial combustion systems utilizing fuel nozzles. [Background technology]

[0003] Many of the problems associated with industrial combustion systems relate to the fuel nozzles, sometimes called burner tips. These fuel nozzles experience varying fuel gas composition, high flue gas temperatures, and variable flow rates through the gas tip. This, coupled with high temperatures and fuel contaminants, makes the fuel nozzle susceptible to fouling and the buildup of carbon deposits, also known as "coking," which can require complete replacement of the fuel nozzle over time. Furthermore, high temperatures can degrade the nozzle material, also necessitating fuel nozzle replacement. Replacement parts, along with combustion system downtime and labor costs to replace the nozzle, can result in significant costs to the end user.

[0004] Accordingly, the industrial combustion technology field is of great interest in systems and methods that reduce fouling and coking and / or otherwise extend the life of fuel nozzles. Summary of the Invention

[0005] FIELD OF THE DISCLOSURE Embodiments of the present disclosure relate to systems and methods associated with the use of such systems. The system generally relates to fuel nozzles for use in industrial combustion systems.

[0006] In some embodiments, a fuel nozzle includes an elongated body defining a fuel inlet port at a first end and terminating at a burner tip at a second end. The elongated body has an inner surface defining a lumen extending longitudinally within the elongated body from the inlet port to the burner tip, the inner surface having a longitudinally extending portion and an inner tip portion. The elongated body has an outer surface having side portions and an outer tip portion. The tip defines a fuel port having an inner opening at the inner tip portion and an outer opening at the outer tip portion. The inlet port, the lumen, and the inner opening are in fluid communication such that at least a portion of fuel entering the inlet port passes through the lumen, through the inner opening, and out the outer opening.

[0007] In some embodiments, the fuel nozzle has one or more of the following features: (a) at least one ridge defined on a longitudinally extending portion of the inner surface; (b) an exterior insulating layer covering at least a portion of the side portion of the exterior surface; (c) an inner opening having a sloped section; and / or (d) The fuel port further defines a cavity located between the inner opening and the outer opening, the cavity providing a pressure drop for fuel passing from the inner opening to the outer opening.

[0008] Additionally, in some embodiments, the ridges may be configured to create a tangential flow of fuel through the bore, thereby improving mixing. In some embodiments, the ridges extend helically along the longitudinally extending portion of the inner surface.

[0009] Additionally, in some embodiments, the insulating layer may be formed by a lattice structure defining a plurality of small holes, or optionally, the insulating layer may be formed by a shell separated from the outer surface by a plurality of fins to form a plurality of air pockets between the shell and the outer surface. Typically, the insulating layer is configured to create a void zone of about 50% to about 80%, optionally about 80%.

[0010] In some embodiments, the inner opening may have a first diameter and the outer opening may have a second diameter that is larger than the first diameter.

[0011] The disclosed embodiments may be used in a manner in which fuel is delivered in a serpentine path through a fuel nozzle to create a tangential flow of fuel through the bore of the fuel nozzle, thereby improving mixing.

[0012] The disclosed embodiments may be used in methods where fuel exiting a fuel nozzle experiences a pressure drop as it passes from an inner opening to an outer opening. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is an isometric schematic view of an industrial combustion system.

[0014] [Figure 2] FIG. 2 is an elevational schematic view of the industrial combustion system of FIG. 1.

[0015] [Figure 3] FIG. 2 is a schematic side view of the industrial combustion system of FIG. 1.

[0016] [Figure 4] Figure 1.6880 is a schematic diagram of a burner in an industrial combustion system.

[0017] [Figure 5] FIG. 1 is a schematic diagram of a nozzle according to an embodiment of the present disclosure.

[0018] [Figure 6] FIG. 6 is an enlarged view of the upper part of the nozzle shown in FIG. 5.

[0019] [Figure 7] FIG. 7 is a perspective view of a nozzle having an alternative insulating layer to that shown in FIGS. 5 and 6.

[0020] [Figure 8]FIG. 8 is a cross-sectional view of the nozzle of FIG. 7.

[0021] [Figure 9] FIG. 10 is a cross-sectional view of a nozzle according to the present disclosure showing another embodiment of rifling within the nozzle.

[0022] [Figure 10] 10 is an isometric view of the nozzle of FIG. 9 from the bottom of the nozzle showing the rifling of the nozzle bore of FIG. 9.

[0023] [Figure 11] 1 is a diagram of a conventional nozzle design used in Example Cases (1) and (2). DETAILED DESCRIPTION OF THE INVENTION

[0024] The present disclosure may be more readily understood by reference to the following description, including examples. Furthermore, numerous specific details are described to provide a thorough understanding of the embodiments described herein. However, those skilled in the art will understand that the embodiments described herein may be practiced without these specific details. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the relevant features being described. Additionally, the description should not be considered to limit the scope of the embodiments described herein.

[0025] Various embodiments are illustrated and described in the drawings, and like reference numerals are used herein to designate like elements throughout the various views. The drawings are not necessarily drawn to scale, and in some cases, the drawings have been exaggerated and / or simplified in places for illustrative purposes only. Where components of relatively well-known design are used, their structure and operation will not be described in detail. Those skilled in the art will recognize many possible applications and variations of the present disclosure based on the following description.

[0026] The present disclosure is directed to combustion methods, systems, and apparatus designed to extend the life of fuel nozzles used in industrial combustion systems and to reduce coking and fouling of such fuel nozzles.

[0027] As used herein, "industrial combustion system" refers to a mechanical device that mixes fuel and air together and uses an ignition device to provide a platform for combustion. Typically, the fuel in such systems is a fossil fuel, but can be an alternative fuel, such as biogas fuel. Industrial combustion systems are a key component of all boiler and furnace heating systems that provide temperature control throughout manufacturing facilities and other heating processes during manufacturing. Industrial combustion systems include, but are not limited to, devices such as industrial boilers and furnaces, larger utility boilers and furnaces, gas turbine engines, steam generators, and other combustion systems.

[0028] As used herein, the term "fuel nozzle" refers to a nozzle for introducing gas into an industrial combustion system for the controlled combustion of fuel. In some applications, the fuel nozzle introduces only fuel gas. However, the fuel nozzles of the present disclosure can also be used to introduce fuel-air mixtures and fuel-inert gas mixtures, such as inert gases produced during combustion in furnaces or other industrial combustion systems. Additionally, the structures disclosed herein can also be useful in nozzles that introduce only air into industrial combustion systems.

[0029] The fuel nozzles of the present disclosure have one or more features designed to extend their useful life, including reducing fouling and clogging. For example, the fuel nozzle may have one of the following features, or a combination of two, three, or all of the following features: The fuel nozzle may have (a) at least one ridge defined on the inner surface of the nozzle, (b) an outer insulating layer covering at least a portion of a side portion of the outer surface of the nozzle, (c) a sloped section for the inner opening(s) of the fuel port(s) through which fuel exits the nozzle, and / or (d) a pressure drop for fuel exiting the interior of the nozzle through the fuel port(s).

[0030] Referring now to the drawings, features of nozzles according to the present disclosure will be described in more detail. The nozzles of the present disclosure are suitable for use in a variety of industrial combustion systems. For example, FIGS. 1-3 generally illustrate an industrial combustion system 10 that may utilize nozzles of the present disclosure. The industrial combustion system 10 includes a chimney 12, a radiant section 14, and a burner 16. Referring to FIG. 4, the burner 16 includes one or more nozzles 20 that may be in accordance with the disclosure herein.

[0031] Referring now to FIG. 5, a nozzle 20 having features according to the present disclosure is shown. The nozzle 20 is suitable for use in an industrial combustion system 10, such as that shown in FIGS. 1-4. The nozzle 20 comprises an elongated body 22 having a fuel inlet port 24 at a first end 26 and terminating at a second end 30. As shown, the elongated body 22 has a longitudinally extending wall 34 extending from the first end 26 to the second end 30, where the wall terminates at a dome-shaped tip 32. The elongated wall 34 thus has an inner surface 36 including a longitudinally extending portion 38 and an inner tip portion 40. The inner surface 36 defines a bore 42 extending longitudinally within the elongated body from the inlet port 24 to the second end 30. The second end 30 has one or more ports 44 and 46. Nozzle 20 is therefore configured such that fuel, air, inert gas, or a mixture thereof can enter the nozzle through inlet port 24, pass through bore 42, and exit through ports 44 and 46. Although only one port 44 and one port 46 are shown, it will be understood that nozzle 22 may have more than one of any of these ports.

[0032] Ports 44 and 46 are better seen with reference to Figure 6. Port 44 has an inner opening 50 at the interior tip portion 40 and an outer opening 54 (as seen in Figure 7) at the exterior of tip portion 32. As shown, inner opening 50 has a sloped section 52. Sloped section 52 is configured to create a smoother flow profile for gas entering port 44, thus minimizing the creation of a recirculation zone near port 44, which can increase fuel gas residence time and thereby increase coking.

[0033] Port 46 has an inner opening 58 and an outer opening 62. Port 46 is designed to create a pressure drop for gas traveling through port 46. That is, the pressure of the passing gas decreases as the gas traverses port 46. For example, the pressure can be reduced from approximately 5 psi to 15 psi. For example, if the pressure at opening 58 is 10 psia, the pressure at opening 62 can be reduced to 1 psia. In one example, port 46 has an inner cavity 60 for creating the pressure drop. Alternatively, or in addition to cavity 60, outer opening 62 has a larger diameter than inner opening 58 to help create the pressure drop, as suggested by the difference in size of openings 58, 62 in FIG. 6 .

[0034] 5 and 6 , an embodiment of the present disclosure employs at least one ridge 64, also referred to as rifling 64. The ridge 64 is defined on the longitudinally extending portion 38 of the inner surface 36. Generally, the ridge 64 is a helical structure formed on the inner surface 36 configured to disturb the flow of gas through the nozzle 20, creating a tangential flow of the gas through the bore 42 and thereby improving mixing. The use of the ridge 64 tends to induce mixing, thereby preventing stratification of the fuel gas as it flows through the nozzle 20. By promoting mixing, the gas, particularly the fuel gas, may be maintained closer to a bulk flow temperature, which is typically similar to ambient conditions. For example, the ridge 64 may extend helically along the longitudinally extending portion of the inner surface 36.

[0035] Embodiments of the nozzle 20 utilize an external insulating layer 72. The external insulating layer 72 typically covers at least a portion of the exterior surface 66, including the side portions 68 and the exterior tip portion 70. Generally, the insulating layer 72 covers all or at least a majority (greater than 90%) of the exterior surface 66. In the embodiment shown in FIGS. 5 and 6, the insulating layer 72 includes a shell 74 spaced from the exterior surface 66 by a plurality of fins 76 spaced about the periphery of the exterior surface 66 and extending to the shell 74 to form a plurality of air pockets 78 between the shell 74 and the exterior surface 66. In this embodiment, the shell 74 is embodied as a solid or continuous surface such that it does not have any holes or spaces along the exterior surface 92 covering the side portions 68 and the exterior tip portion 70, other than those required for the ports 44 and 46.

[0036] 7 and 8, another embodiment of the insulating layer 72 is shown. The insulating layer 72 in this embodiment is formed by a lattice structure 80 defining a plurality of small holes 82. In the illustrated embodiment or other embodiments, the insulating layer 72 should be configured to insulate the nozzle 20 from the temperature of the ambient environment. Thus, the insulating layer 72 reduces heat transfer from the ambient environment to the fuel gas flowing through the nozzle 20. Coking within the nozzle 20 is a function of temperature; higher temperatures result in greater hydrocarbon cracking and coking of cracking products. In at least some embodiments, the insulating layer 72 of the present disclosure provides voids to insulate the nozzle, even when the nozzle and insulating layer 72 are made of metallic materials. For example, the insulating layer 72 can be configured to create a void zone of about 50% to about 80%, optionally about 80%. The void zone in the illustrated embodiment is an air pocket 78 or a small hole 82.

[0037] Another embodiment of a nozzle 120 according to the present disclosure is shown in Figures 7-8. The embodiment of Figures 7-8 has an internal gas flow structure similar to the embodiment of the nozzle 20 described above. The nozzle 120 includes a grid pattern that forms an outer insulation layer 172 covering the outer tip portion 170. Accordingly, the insulation layer 172 in the outer tip portion 170 has a lattice structure 80 that defines a plurality of small holes 82. Typically, fuel gas does not flow through the lattice structure 80. Rather, the small holes 82 are in fluid communication with the surrounding furnace environment, rather than the fuel bore 42. Thus, furnace gases from the surrounding furnace environment can diffuse into the small holes 82.

[0038] 9-10, another embodiment of a nozzle 220 has rifling 63 with one or more ridges 64. The one or more ridges 64 form a serpentine or winding passage 65 within the bore 142, thereby promoting mixing of the gases flowing through the passage 65. As can be better seen by viewing FIGS. 9 and 10 together, the embodiment shown in FIGS. 9 and 10 has rifling 63 with three intertwining ridges 64. That is, the three ridges 64 spiral up the pore 142 such that the ridges 64 are spaced apart and generally parallel to one another. FIG. 10 shows the base 84 of the nozzle 220. The fuel inlet port 124 is surrounded by three lobe shapes 86, with the sidewall 88 of each lobe shape 86 formed on a corresponding one of the three ridges 64, thus twisting along the length of the inner bore 142 of the nozzle 220.

[0039] 9, at the downstream end of nozzle 220, nozzle 220 has an expansion chamber 90 that receives fuel flowing from bore 142. The fuel then exits expansion chamber 90 through outlet port 144 (and, if used, outlet port 146). Expansion chamber 90 is configured to create a pressure drop on the fuel coming from bore 142 before entering outlet port 144.

[0040] Thus, during operation, fuel enters through the inlet port 124. As the fuel passes through the bore 142, the three ridges 64 create a tangential (swirl) component to the gas, thereby improving mixing and temperature uniformity for heat transfer to the gas. By using a highly swirled zone (via rotating lobes / ridges or other structures) and exiting into the expansion chamber 90, the tip 172 of the nozzle 220 has been found to create an oscillatory pressure behavior and therefore an oscillatory or pulsating behavior in the exiting fuel gas stream. This may be desirable in certain applications.

[0041] Pulse combustion, the process of oscillating the flow of air or fuel within a combustion chamber, has the potential to provide performance benefits to combustion systems through increased mass and heat transfer. Pulse combustion can increase radiative heat transfer and reduce NOx emissions. Traditional approaches to generating pulsating flow require complex external components (e.g., rotary valves), and pressure oscillations can be damped between these components and the combustion process. However, pulsating flow can be generated through a much simpler structure using embodiments of the present disclosure. By generating a very large vortex within the center body of the fuel gas nozzle 220 followed by an expansion chamber 90, a precessing vortex core can be generated. This precessing vortex core creates an oscillating rotational flow within the expansion chamber 90 within the nozzle 220, thereby providing a pulsating fuel gas flow. The frequency and amplitude of the pulsation can be controlled by changing the nozzle geometry to affect the vortex flow. Furthermore, because the pulsation can be localized to individual fuel gas nozzles, it is possible to optimize which nozzles do not have pulsation to optimize burner stability and reliability, while utilizing pulsating jets on other fuel zones to optimize combustion performance. Although described with respect to fuel gas, the design of the nozzle 120 can be applied to other gases, such as air, when the nozzle is used for injection and a pulsating flow is desired.

[0042] The nozzles 20, 120, 220 and the insulating layer 72, 172, if used, can be made from any suitable material. Advantageously, they can be made from metal, such as steel and / or stainless steel. Metal nozzles 20, 120, 220 with insulating layers 72, 172 according to the present disclosure advantageously have lower thermal conductivity than typically achieved only with ceramic materials, while avoiding the drawbacks of ceramics, such as brittleness. Furthermore, the metal nozzles 20, 120, 220 and / or the insulating layer 72, 172 can be easily manufactured using 3D printing techniques. Accordingly, some embodiments of the present disclosure include manufacturing the nozzles 20, 120, 220 and / or their insulating layers 72, 172 by 3D printing.

[0043] The nozzles 20, 120, 220 of the present disclosure can be further understood by reference to the following examples that illustrate the advantages and features of the disclosed nozzles 220.

[0044] Working Example:

[0045] The nozzle design was analyzed for a single-burner industrial combustion system, as shown in Figure 1, by computer simulation using Simcenter Star-CCM+ 1702. Simcenter STAR-CCM+ is a multiphysics computational fluid dynamics (CFD) software by Siemens. The simulation setup was calibrated to match bed and arch temperatures reported from a commercially used coker unit.

[0046] Three different cases were compared: (1) a base control case with a conventional nozzle design made from stainless steel 316; (2) case (a) the conventional nozzle design but made from ceramic; and (3) a design according to the present disclosure made from stainless steel 316. Case (3) used a design similar to that described in Figure 9, where the nozzle had a checkerboard pattern on the tip and rifling on the interior surface to form the bore. A diagram of the design used for cases (1) and (2) is shown in Figure 11.

[0047] For each case, a calibrated base case simulation setup was used by replacing one of the two stepped tips. Temperatures at the outer and inner surfaces of the tip, the port, and the non-filleted interface within the port-tip were reported to study the effect of geometry and materials on the overall heat transfer in each case. The following parameters were used in modeling the performance of each case: · Compressible multicomponent ideal gases; · Steady state; · Standard K-epsilon model; · 2 layers of all y+ treatment; · Hybrid vortex breakdown combustion model; · Thermal radiation using the discrete ordinates method; · Weighted sum of grey gases; · Fluid-solid interface modeled using conjugate heat transfer; · The fuel gas and air inlets are modeled as mass flow inlet boundaries; · The chimney outlet is modeled as a pressure outlet; · One of the step-wise tips is considered solid, considering the conjugate heat transfer from the fluid to the solid region; · Radiation from the flame is the main source of heat for the solid tip; The solid tip is provided with a riser to take into account the flow effect from the fuel inlet to the tip; · Excess airflow: 26.7% (matches 4.03% wet O2 measurement); Ambient air temperature: 60°F Relative humidity: 85% at 60°F Fuel gas temperature: 71°F Combustion air temperature: 506.8°F Air flow rate per burner: 1616.9 lb / hr Fuel flow rate per burner: 80.8 lb / hr; and Heat output per burner: 1.62 MMBTU / hr.

[0048] The modeled air composition and fuel gas composition are shown in Tables 1 and 2. [Table 1] [Table 2]

[0049] A thermal analysis was performed to determine the flame power output for each case, and the thermal results are summarized in Table 3 below. [Table 3]

[0050] The results showed that all three designs produced similar flames from the nozzle. The average CO isosurface area at 2000 (parts per million by volume, ppmvd) dry for Cases 2 and 3 was within ±0.1 ft of 6.3 ft for Case 1. The floor and arch temperatures for Cases 2 and 3 were within ±20°F of Case 1. Thus, the results were qualitatively the same for all three cases, and the modifications made for Case 3 did not affect the overall flame results.

[0051] An analysis of the calculated cross-sectional linear velocity vectors within each nozzle was determined. For Cases 1 and 2, the nozzle's internal configuration (shown in Figure 11) was that of a standard tube, and the tangential velocity vectors did not exhibit much mixing. Case 3, with its modified geometry, exhibited significant fluid mixing with a recirculation zone toward the nozzle center. Furthermore, the results show that the twisted interior of Case 3 promoted the breakdown of thermal boundaries and improved convective cooling as the fluid was continuously washed away from the nozzle's internal walls.

[0052] Furthermore, as shown in Table 3 above, there was no significant pressure drop between Cases 1, 2, and 3 due to the geometry changes to Case 3. For Case 3, the external surface temperature was lower than for Cases 1 and 2, dropping by over 100°F in the nozzle body. The internal tip surface temperature for Case 3 also dropped substantially. Case 3 had the smallest peak-to-average gas temperature difference, indicating significantly improved heat transfer and resulting in cooler tip surfaces overall. The tip ports, primarily the ignition port and the tip internal connection boundary, are where coke formation is expected to begin. However, Case 3 showed a temperature improvement of approximately 280°F over Case 1 on these coke-forming surfaces. Meanwhile, Case 2 showed only a 70°F improvement over Case 1.

[0053] Therefore, under the same simulation conditions, modifying the tip shape in accordance with the present disclosure did not affect the overall combustion results and did not result in a significant pressure drop within the nozzle. However, the nozzle design in accordance with the present disclosure exhibited significant temperature and heat transfer conditions that would promote reduced coke formation.

[0054] Thus, the nozzle 20 described herein is an improvement over existing technology, as conventional nozzles 20 were devices used simply to inject fuel gas into specific areas of a burner without consideration of heat transfer effects, flow profile, or velocity. The inventors have realized for the first time the benefits achieved by designing a nozzle 20 with consideration of heat transfer effects, flow profile, and / or velocity. Thus, the nozzle 20 of the present disclosure addresses the problem of coking and plugging, which can be costly in terms of spare parts and labor.

[0055] The systems and methods of the present disclosure can be further understood by the following numbered paragraphs, which describe some of the variations in the structure of the embodiments of the present disclosure.

[0056] Paragraph 1. A fuel nozzle for an industrial combustion system, comprising: an elongate body defining a fuel inlet port at a first end and terminating in a tip at a second end; an inner surface defining a lumen extending longitudinally within the elongate body from an inlet port to a distal end, the inner surface having a longitudinally extending portion and an inner distal end portion; at least one ridge defined on the longitudinally extending portion of the inner surface; an outer surface having side portions and an outer tip portion; the tip defines a fuel port having an inner opening at an inner tip portion and an outer opening at an outer tip portion; The fuel nozzle, wherein the inlet port, the bore, and the inner opening are in fluid communication such that at least a portion of fuel entering the inlet port passes through the bore, through the inner opening, and out the outer opening.

[0057] Paragraph 2. The fuel nozzle of paragraph 1, wherein the ridge is configured to generate a tangential flow of fuel through the bore, thereby improving mixing.

[0058] Paragraph 3. The fuel nozzle of either paragraph 1 or paragraph 2, wherein the ridge extends helically along a longitudinally extending portion of the inner surface.

[0059] Paragraph 4. The fuel nozzle of any one of the preceding paragraphs, further comprising an expansion chamber defined by the tip and in fluid communication with the bore and the inner opening, wherein fuel in the bore flows into the expansion chamber before entering the inner opening.

[0060] Paragraph 5. The fuel nozzle of any one of the preceding paragraphs, wherein the inner opening has an inclined section.

[0061] Paragraph 6. The fuel nozzle of any one of the preceding paragraphs, wherein the fuel port further defines a cavity located between the inner opening and the outer opening, the cavity providing a pressure drop for fuel passing from the inner opening to the outer opening.

[0062] Paragraph 7. The fuel nozzle of paragraph 6, wherein the inner opening has a first diameter and the outer opening has a second diameter, the second diameter being larger than the first diameter.

[0063] Paragraph 8. The fuel nozzle of any one of the preceding paragraphs, further comprising an external insulating layer covering at least a portion of a side portion of the outer surface.

[0064] Paragraph 9. The fuel nozzle of paragraph 8, wherein the insulating layer is formed by a lattice structure defining a plurality of small holes.

[0065] Paragraph 10. The fuel nozzle of paragraph 8, wherein the insulating layer is formed by a shell separated from the outer surface by a plurality of fins, forming a plurality of air pockets between the shell and the outer surface.

[0066] Paragraph 11. The fuel nozzle of any one of Paragraphs 8-10, wherein the insulating layer is configured to form a void zone of between about 50% and about 80%, optionally about 80%.

[0067] Paragraph 12. A fuel nozzle for an industrial combustion system, comprising: an elongate body defining a fuel inlet port at a first end and terminating in a tip at a second end; an inner surface defining a lumen extending longitudinally within the elongate body from an inlet port to a distal end, the inner surface having a longitudinally extending portion and an inner distal end portion; an elongated body having an outer surface with side portions and an outer tip portion, the burner tip defining a fuel port having an inner opening at the inner tip portion and an outer opening at the outer tip portion; an external insulating layer covering at least a portion of the side portion of the exterior surface; The fuel nozzle, wherein the inlet port, the bore, and the inner opening are in fluid communication such that at least a portion of fuel entering the inlet port passes through the bore, through the inner opening, and out the outer opening.

[0068] Paragraph 13. The fuel nozzle of paragraph 12, wherein the insulating layer is formed by a lattice structure defining a plurality of small holes.

[0069] Paragraph 14. The fuel nozzle of paragraph 12, wherein the insulating layer is formed by a shell separated from the outer surface by a plurality of fins, forming a plurality of air pockets between the shell and the outer surface.

[0070] Paragraph 15. The fuel nozzle of any one of Paragraphs 12-14, wherein the insulating layer is configured to form a void zone of between about 50% and about 80%, optionally about 80%.

[0071] Paragraph 16. The fuel nozzle of any one of Paragraphs 12 to 15, wherein the inner opening has an inclined section.

[0072] Paragraph 17. A fuel nozzle according to any one of paragraphs 12 to 16, wherein the fuel port further defines a cavity located between the inner opening and the outer opening, the cavity providing a pressure drop for fuel passing from the inner opening to the outer opening.

[0073] Paragraph 18. The fuel nozzle of paragraph 17, wherein the inner opening has a first diameter and the outer opening has a second diameter, the second diameter being greater than the first diameter.

[0074] Paragraph 19. The fuel nozzle of any one of Paragraphs 12-18, wherein the elongated body further includes at least one ridge defined on a longitudinally extending portion of the inner surface, the ridge configured to generate a tangential flow of fuel passing through the bore, thereby improving mixing.

[0075] Paragraph 20. The fuel nozzle of Paragraph 19, wherein the ridge extends helically along the longitudinally extending portion of the inner surface.

[0076] Paragraph 21. The fuel nozzle of either Paragraph 19 or 20, further comprising an expansion chamber defined by the tip and in fluid communication with the bore and the inner opening, wherein fuel in the bore flows into the expansion chamber before entering the inner opening.

[0077] Although compositions and methods are described in terms such as "comprising," "containing," or "including" various components or steps, compositions and methods can also "consist essentially of" or "consist of" various components and steps. Whenever a numerical range with a lower and upper limit is disclosed, any number and any included range within that range is specifically disclosed. In particular, all ranges of values ​​disclosed herein (in the form "from about a to about b," or, equivalently, "from approximately a to b," or, equivalently, "from approximately a to b") should be understood to describe all numbers and ranges encompassed within the broader range of values. In addition, when the term "about" is used in connection with a range, it generally means plus or minus half of the last significant digit of the range value, unless the context dictates that a different definition of "about" applies.

[0078] Also, terms in the claims have their plain and ordinary meaning unless expressly and clearly defined by the patentee. Additionally, when used in the claims, the indefinite articles "a" or "an" are defined herein to mean one or more than one of the elements they introduce. In the event of a discrepancy in the use of a word or term in this specification and one or more patent(s) or other documents that may be incorporated herein by reference, the definition consistent with this specification shall prevail.

Claims

1. 1. A fuel nozzle for an industrial combustion system, comprising: an elongated body defining a fuel inlet port at a first end and terminating in a tip at a second end; an inner surface defining a lumen extending longitudinally within the elongate body from the inlet port to the tip, the inner surface having a longitudinally extending portion and an inner tip portion; at least one ridge defined on the longitudinally extending portion of the inner surface; an outer surface having side portions and an outer tip portion; the tip defines a fuel port having an inner opening at the inner tip portion and an outer opening at the outer tip portion; The inlet port, the bore, and the inner opening are in fluid communication such that at least a portion of fuel entering the inlet port passes through the bore, through the inner opening, and out the outer opening.

2. The fuel nozzle of claim 1 , wherein the ridge is configured to create a tangential flow of fuel through the bore, thereby improving mixing.

3. The fuel nozzle of claim 1 , wherein the ridge extends helically along the longitudinally extending portion of the inner surface.

4. 10. The fuel nozzle of claim 1, further comprising an expansion chamber defined by the tip and in fluid communication with the bore and the inner opening, wherein fuel within the bore flows into the expansion chamber before entering the inner opening.

5. The fuel nozzle of claim 1 , wherein the inner opening has an angled section.

6. 2. The fuel nozzle of claim 1, wherein the fuel port further defines a cavity located between the inner opening and the outer opening, the cavity providing a pressure drop for fuel passing from the inner opening to the outer opening.

7. The fuel nozzle of claim 6 , wherein the inner opening has a first diameter and the outer opening has a second diameter, the second diameter being greater than the first diameter.

8. The fuel nozzle of claim 1 , further comprising an outer thermal insulation layer covering at least a portion of the side portion of the outer surface.

9. The fuel nozzle of claim 8 , wherein the thermal insulation layer is formed by a lattice structure defining a plurality of small holes.

10. The fuel nozzle of claim 8 , wherein the thermal insulation layer is formed by a shell separated from the outer surface by a plurality of fins, forming a plurality of air pockets between the shell and the outer surface.

11. The fuel nozzle of claim 8 , wherein the thermal insulation layer is configured to form a void zone of between about 50% and about 80%, optionally about 80%.

12. A fuel nozzle according to any one of claims 2 or 4 to 11, wherein the ridge extends helically along the longitudinally extending portion of the inner surface.

13. 12. The fuel nozzle of claim 2, further comprising an expansion chamber defined by the tip and in fluid communication with the bore and the inner opening, wherein fuel in the bore flows into the expansion chamber before entering the inner opening.

14. The fuel nozzle of any one of claims 2 to 4 or 6 to 11, wherein the inner opening has an angled section.

15. 12. The fuel nozzle of claim 2, wherein the fuel port further defines a cavity located between the inner opening and the outer opening, the cavity providing a pressure drop for fuel passing from the inner opening to the outer opening.

16. The fuel nozzle of any one of claims 2 to 7 or 9 to 11, further comprising an external insulating layer covering at least a portion of the side portion of the outer surface.

17. The fuel nozzle of claim 10 or 11, wherein the thermal insulation layer is configured to form a void zone of between about 50% and about 80%, optionally about 80%.

18. 1. A fuel nozzle for an industrial combustion system, comprising: an elongated body defining a fuel inlet port at a first end and terminating in a tip at a second end; an inner surface defining a lumen extending longitudinally within the elongate body from an inlet port to said tip, the inner surface having a longitudinally extending portion and an inner tip portion; an elongated body having an exterior surface with side portions and an exterior tip portion, the burner tip defining a fuel port having an inner opening at the interior tip portion and an outer opening at the exterior tip portion; an external insulating layer covering at least a portion of the side portion of the exterior surface; The inlet port, the bore, and the inner opening are in fluid communication such that at least a portion of fuel entering the inlet port passes through the bore, through the inner opening, and out the outer opening.

19. The fuel nozzle of claim 17 , wherein the thermal insulation layer is formed by a lattice structure defining a plurality of small holes.

20. The fuel nozzle of claim 17 , wherein the thermal insulation layer is formed by a shell separated from the outer surface by a plurality of fins, forming a plurality of air pockets between the shell and the outer surface.

21. The fuel nozzle of claim 17 , wherein the thermal insulation layer is configured to form a void zone of between about 50% and about 80%, optionally about 80%.

22. The fuel nozzle of claim 17 , wherein the inner opening has an angled section.

23. 18. The fuel nozzle of claim 17, wherein the fuel port further defines a cavity located between the inner opening and the outer opening, the cavity providing a pressure drop for fuel passing from the inner opening to the outer opening.

24. 24. The fuel nozzle of claim 23, wherein the inner opening has a first diameter and the outer opening has a second diameter, the second diameter being larger than the first diameter.

25. 18. The fuel nozzle of claim 17, wherein the elongated body further includes at least one ridge defined on the longitudinally extending portion of the inner surface, the ridge configured to shape a tangential flow of fuel passing through the bore, thereby improving mixing.

26. The fuel nozzle of claim 25 , wherein the ridge extends helically along the longitudinally extending portion of the inner surface.

27. 27. The fuel nozzle of claim 26, further comprising an expansion chamber defined by the tip and in fluid communication with the bore and the inner opening, fuel in the bore flowing into the expansion chamber before entering the inner opening.

28. 26. The fuel nozzle of claim 25, further comprising an expansion chamber defined by the tip and in fluid communication with the bore and the inner opening, fuel in the bore flowing into the expansion chamber before entering the inner opening.

29. 23. The fuel nozzle of claim 18, wherein the fuel port further defines a cavity located between the inner opening and the outer opening, the cavity providing a pressure drop for fuel passing from the inner opening to the outer opening.

30. 25. The fuel nozzle of claim 18, wherein the elongated body further includes at least one ridge defined on the longitudinally extending portion of the inner surface, the ridge configured to create a tangential flow of fuel passing through the bore, thereby improving mixing.

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