EP4646559A1 - Fuel nozzle for use in an industrial combustion system - Google Patents

Abstract

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

Description

FUEL NOZZLE FOR USE IN AN INDUSTRIAL COMBUSTION SYSTEM

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit under 35 USC § 119(e) of U.S. Provisional Application Serial No. 63/478,701, filed on January 6, 2023 and U.S. Provisional Application Serial No. 63/522,438, filed on June 22, 2023, the entire disclosures of both of which are incorporated herein by reference.

FIELD

[0002] This disclosure relates to the field of combustion, and more particularly but not by way of limitation, industrial combustion systems utilizing fuel nozzles.

BACKGROUND

[0003] Many of the problems associated with industrial combustion systems are related to the fuel nozzles, sometimes referred to as burner tips. Such fuel nozzles are subjected to variable fuel gas composition, high flue gas temperature, and variable flow rate through the gas tip. Added to this are high temperatures and fuel contaminants. The combination of these variables makes the fuel nozzles susceptible to fouling and the buildup of carbon deposits, also known as “coking,” which over time can require a complete replacement of the fuel nozzles. Additionally, the high temperatures can degrade the material of the nozzle, also requiring replacement of the fuel nozzles. The replacement parts along with the combustion system downtime and labor costs to replace the nozzles can result in significant costs to the end user.

[0004] Accordingly, the industrial combustion art area has a high interest in systems and methods that reduce fouling and coking and/or otherwise extend the life of fuel nozzles.

SUMMARY OF THE INVENTION

[0005] Embodiments of this disclosure relate to systems and methods related to the use of the systems. The systems generally are directed to a fuel nozzle for use in an industrial combustion system.

[0006] In some embodiments, a fuel nozzle comprises an elongated body defining a fuel inlet port at a first end and terminating in a burner tip at a second end. The elongated body has an interior surface defining a bore extending longitudinally in the elongated body from the inlet port to the burner tip such that the interior surface has a longitudinally-extending portion and an interior-tip portion. The elongated body has an exterior surface having a side portion and an exterior-tip portion. The tip defines a fuel port having an inner orifice at the interior-tip portion and an outer orifice at the exterior-tip portion. The inlet port, bore and inner orifice are in fluid flow communication so that at least a portion of fuel entering the inlet port flows through the bore, through the inner orifice and out the outer orifice.

[0007] In the some embodiments, the fuel nozzle has one or more of the following features:

(a) at least one ridge defined on the 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) the inner orifice having a beveled section; and/or

(d) the fuel port further defining a cavity located between the inner orifice and exterior orifice such that the cavity results in a pressure drop in fuel passing from the inner orifice to the exterior orifice.

[0008] Further, in some embodiments, the ridge may be configured to create tangential flows of fuel passing through the bore to improve mixing. In some embodiments, the ridge extends spirally along the longitudinally-extending portion of the interior surface.

[0009] Still further, in some embodiments, the insulating layer may be formed by a lattice structure defining a plurality of pores, or optionally, the insulating layer may be formed by a shell separated from the exterior surface by a plurality of fins so as to form a plurality of air-pockets between the shell and the exterior surface. Typically, the insulating layer is configured to create from about 50% to about 80% void zones, and optionally about 80% void zones.

[0010] In some embodiments, the inner orifice has a first diameter and the exterior orifice may have a second diameter that is greater than the first diameter.

[0011] The disclosed embodiments may be used in a method wherein fuel is provided a tortuous path through a fuel nozzle such as to create tangential flows of fuel passing through the bore of the fuel nozzle to thus improve mixing.

[0012] The disclosed embodiments may be used in a method wherein fuel exiting the fuel nozzle undergoes a pressure drop in passing from the inner orifice to the exterior orifice.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 is an isometric schematic illustration of an industrial combustion system. [0014] FIG. 2 is an elevation schematic illustration of the industrial combustion system of FIG. 1.

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

[0016] FIG. 4 is a schematic illustration of burner of the industrial combustion system of FIG. 1.6880

[0017] FIG. 5 is a schematic illustration of a nozzle in accordance with embodiments to of this disclosure.

[0018] FIG. 6 is an enlargement of the upper portion of the nozzle illustrated in FIG. 5.

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

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

[0021] FIG. 9 is a sectional view of a nozzle in accordance with this disclosure that shows another embodiment of rifling within the nozzle.

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

[0023] FIG. 11 is an illustration of a conventional nozzle design used for case (1) and case (2) of the Example.

DESCRIPTION

[0024] The present disclosure may be understood more readily by reference to the following description including the examples. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, those of ordinary skill in the art will understand that the embodiments described herein can 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 related relevant feature being described. Additionally, the description is not to be considered as limiting the scope of the embodiments described herein.

[0025] In the drawings, various embodiments are illustrated and described wherein like reference numbers are used herein to designate like elements throughout the various views. The figures are not necessarily drawn to scale, and in some instances the drawings have been exaggerated and/or simplified in places for illustrative purposes only. Where components of relatively well-known designs are employed, their structure and operation will not be described in detail. One of ordinary skill in the art will appreciate the many possible applications and variations of the present disclosure based on the following description.

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

[0027] As used herein “industrial combustion systems” refers to a mechanical device that mixes fuel and air together — and, using an ignition device, provides a platform for combustion. Generally, the fuel for such systems are fossil fuels, but can also be alternative fuels such as biogas fuels. Industrial combustion systems are a key component of every boiler and furnace heating system that provides temperature control throughout entire manufacturing facilities, as well as other heating processes during manufacturing. Industrial combustion systems include devices such as, but not limited to, industrial boilers and furnaces, larger utility boilers and furnaces, gas turbine engines, steam generators, and other combustion systems.

[0028] The term “fuel nozzle” as used herein refers to nozzles for introducing gasses into an industrial combustion system for controlled burning of a fuel. In some applications, the fuel nozzles will introduce only fuel gas; however, the fuel nozzles of this disclosure can also be used for the introduction of fuel-air mixtures and fuel-inert gas mixtures — such as, inert gases produced during combustion in a furnace, or other industrial combustion system. Additionally, the structures disclosed herein may also be useful in nozzles that introduce only air into the industrial combustion system.

[0029] The fuel nozzles of this disclosure have one or more features designed to extend their useful life, including reducing fouling and clogging. For example, the fuel nozzles may have one of the following features, or may have 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 exterior insulating layer covering at least a portion of the exterior surface of the nozzle; (c) a beveled section for the inner orifice(s) of the fuel port(s) through which fuel exists from the nozzle; and/or (d) a pressure drop for the fuel exiting from the interior of the nozzle through the fuel port(s).

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

[0031] Turning now to FIG. 5, a nozzle 20 having features in accordance with this disclosure is illustrated. Nozzle 20 is suitable for use in industrial combustion systems 10, such as that illustrated in FIGS. 1-4. The nozzle 20 comprises an elongated body 22, which has a fuel inlet port 24 at a first end 26 and terminates in a second end 30. As illustrated, elongated body 22 has a longitudinally extending wall 34 extending from the first end 26 to the second end 30 where it terminates in a dome shaped tip 32. Thus, elongated wall 34 has an interior surface 36 comprising longitudinally-extending portion 38 and interior-tip portion 40. Interior surface 36 defines a bore 42 extending longitudinally in the elongated body from inlet port 24 to the second end 30. Second end 30 has one or more ports 44 and 46. Thus, the arrangement of nozzle 20 is such that fuel, air, inert gases or mixtures thereof can flow into the nozzle through inlet port 24, through bore 42 and out through ports 44 and 46. While only shown with one port 44 and one port 46, it will be understood that the nozzle 22 may have multiple of either of these ports.

[0032] Ports 44 and 46 can be better seen with reference to FIG. 6. Port 44 has an inner orifice 50 at interior tip portion 40 and an outer orifice 54 (as seen in FIG. 7) at the exterior of the tip portion 32. As illustrated, inner orifice 50 has beveled section 52. Beveled section 52 is configured to create a smoother flow profile for the gas to enter port 44 thus minimizing creation of recirculation zones near port 44, which can increase residence time of fuel gas and thereby increase coking.

[0033] Port 46 has an inner orifice 58 and outer orifice 62. Port 46 is designed so as to create a pressure drop for gasses moving through port 46. That is, the pressure of gases moving through is reduced as they traverse the port 46. For example, pressure can be reduced from about 5 to 15 psi. For example, if the pressure at orifice 58 is 10 psia, the pressure at orifice 62 can be reduced to 1 psia. In one example, port 46 has an inner cavity 60 to produce a pressure drop. Alternatively, or in addition to cavity 60, outer orifice 62 has a larger diameter than inner orifice 58 to help generate the pressure drop as suggested by differences in the size of the orifices 58, 62 in Fig. 6.

[0034] Embodiments of the disclosure employ at least one ridge 64, also referred to as rifling 64, as shown in FIGS. 5 and 6. Ridge 64 is defined on the longitudinally-extending portion 38 of the inner surface 36. Generally, ridge 64 is a helical structure formed on the inner surface 36 that is configured to disrupt the flow of gases through the nozzle 20 to create tangential flows of gases passing through the bore 42 to thus improve mixing. The use of ridges 64 tends to induce mixing and thereby prevent stratification of fuel gas as it flows through the nozzle 20. By enhancing mixing, the gases, and in particular fuel gas, may be kept closer to the bulk flowing temperature which is normally similar to ambient conditions. For example, ridge 64 may extend spirally along the longitudinally-extending portion of the inner surface 36.

[0035] Embodiments of the nozzle 20 employ an exterior insulating layer 72. Exterior insulating layer 72 covers at least a portion of exterior surface 66, which typically includes side portion 68 and exterior-tip portion 70. Generally, insulating layer 72 covers all or at least a majority (greater than 90%) of exterior surface 66. In the embodiment illustrated in FIGS. 5 and 6, the insulating layer 72 has a shell 74 spaced from exterior surface 66 by a plurality of fins 76 spaced about the periphery of the exterior surface 66 and extending to the shell 74 so as to form a plurality of air-pockets 78 between the shell 74 and the exterior surface 66. In this embodiment, shell 74 is embodied as a solid or continuous surface so as not to have any holes or spaces along its outer surface 92 covering side portion 68 and exterior-tip portion 70 other than those needed for ports 44 and 46.

[0036] Turning now to FIGS. 7 and 8, another embodiment of the insulating layer 72 is illustrated. The insulating layer 72 in this embodiment is formed by a lattice structure 80 defining a plurality of pores 82. In the illustrated embodiment or in other embodiments, the insulating layer 72 should be configured to insulate the nozzle 20 from the temperatures of the surrounding environment. Thus, the insulating layer 72 decreases heat transfer from the surrounding environment to the fuel gas flowing through the nozzle 20. Coking in the nozzle 20 is a function of temperature — the higher the temperature the greater the breakdown of hydrocarbons and agglomeration of the breakdown products (coking). In at least some embodiments, the insulating layer 72 of this disclosure provides for voids so as to insulate the nozzle even when the nozzle and insulating layer 72 are made from metal materials. For example, the insulating layer 72 can be configured to create from about 50% to about 80% void zones, and optionally about 80% void zones. Void zones in the illustrated embodiments are air-pockets 78 or pores 82.

[0037] Another embodiment of a nozzle 120 in accordance with this disclosure is shown in FIGS. 7-8. The embodiment of FIGS. 7-8 has an internal structure for the flow of gas that is similar to the embodiment of nozzle 20 discussed above. The nozzle 120 includes a grid pattern forming an exterior insulating layer 172 covering the exterior-tip portion 170. Thus, the insulating layer 172 at exterior-tip portion 170 has a lattice structure 80 defining a plurality of pores 82. Typically, no fuel gas will flow through the lattice structure 80; rather, the pores 82 are in fluid flow communication with the surrounding furnace environment and not the fuel bore 42. Thus, furnace gases from the surrounding furnace environment can diffuse into pores 82. [0038] Referring now to FIGS. 9-10, another embodiment of nozzle 220 has rifling 63, which comprise one or more ridges 64. The one or more ridges 64 forms a tortuous or serpentine passage 65 in bore 142, which enhances mixing of the gases flowing through passage 65. As can be better seen from looking at FIGS. 9 and 10 together, the embodiment as illustrated in FIGS. 9 and 10 has rifling 63 comprising three intertwined ridges 64. That is the three ridges 64 spiral up bore 142 such that the ridges 64 are spaced apart and generally parallel to each other. Fig. 10 illustrates the base 84 of the nozzle 220. Fuel inlet port 124 is surrounded by three lobe shapes 86 wherein the side wall 88 of each lobe shape 86 forms into corresponding respective one of the three ridges 64; thus, twisting along the length of inner bore 142 of the nozzle 220.

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

[0040] Thus, in operation fuel enters through inlet port 124. As the fuel passes through bore 142, the three ridges 64 generate a tangential (swirl) component to the gas, and thereby, improve mixing and temperature uniformity for heat transfer to the gas. It has been found that by using a highly swirled zone (via the rotating lobe/ridges or other structure) and exiting into an expansion chamber 90, that a tip 172 of nozzle 220 produces oscillating pressure behavior, thus generating oscillating or pulsed behavior in the exit flows of the fuel gas. This can be desirable for certain applications.

[0041] Pulse combustion (the process to oscillate air or fuel flows within combustion chambers) has the potential to provide performance benefits to combustion systems through increased mass and heat transfer. It is possible to increase radiant heat transfer and reduce NOx emissions with pulse combustion. Traditionally, approaches to creating pulsating flow require complex external components (e.g. rotating valves), and pressure oscillations may attenuate between these components and the combustion process. Pulsating flows, however, can be created with embodiments of this disclosure through a much simpler structure. By creating very high swirl within the central body of fuel gas nozzle 220 followed by an expansion chamber 90, it is possible to create a precessing vortex core. This precessing vortex core forms an oscillating rotating flow within expansion chamber 90 within the nozzle 220 thus providing pulsating fuel gas flows. The frequency and amplitude of the pulsation can be controlled via geometry changes in the nozzle which impact the swirling flow. Further, since 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. While described with respect to fuel gas, the nozzle 120 design can have application to other gases, such air, where a nozzle is used for injection and a pulsating flow is desired.

[0042] The nozzles 20, 120, 220 and the insulating layers 72, 172 if used, can be made of any suitable material. Advantageously, they can be made from metals. For example, steel and/or stainless steel. Metal nozzles 20, 120, 220 with an insulating layer 72, 172 in accordance with this disclosure advantageously have lower thermal conductivity typically only achieved with ceramic materials but avoid the disadvantages of ceramic such as brittleness. Additionally, metal nozzles 20, 120, 220 and/or the insulating layers 72, 172 can be easily manufactured by using 3D printing techniques. Accordingly, some embodiments of the disclosure include manufacturing the above described nozzles 20, 120, 220 and/or its insulating layers 72, 172 by 3D printing.

[0043] The nozzles 20, 120, 220 of this disclosure can be further understood by reference to the following Example which illustrates advantages and features of the disclosed nozzle 220.

[0044] Example:

[0045] Nozzle designs were analyzed for a single burner industrial combustion system, as illustrated in FIG. 1, by computer simulation using Simcenter Star-CCM+ 1702. Simcenter STAR-CCM+ is a multiphysics computational fluid dynamics (CFD) software by Siemens. The simulation settings were calibrated to match floor and arch temperatures of those reported from a commercially used coker unit.

[0046] Three different cases were compared: (1) base control case with a conventional nozzle design made of stainless steel 316; (2) the conventional nozzle design of case (a) but made of ceramic; and (3) a design in accordance with this disclosure using and made with stainless steel 316. Case (3) used a design similar to that discussed for FIG. 9, where the nozzle had a gridded pattern on the tip and rifling on the internal surface forming the bore. An illustration of the design used for case (1) and case 2 is shown in FIG. 11.

[0047] For each case, the calibrated base case simulation settings were used by swapping one of the two staged tips. Temperatures on the tip external surface, internal surface, ports, and port-tip internal non-fdleted boundary section were reported to study the effects of geometry and material on the overall heat transfer in each case. The following parameters were used in modeling the performance of each case;

Compressible multi-component ideal gas;

Steady state; • Standard K-Epsilon model;

• Two-layer all y+ treatment;

• Hybrid eddy breakup combustion model;

• Thermal radiation using Discrete Ordinates Method;

• Weighted sum of gray gases;

• Fluid-solid interface modeled using conjugate heat transfer;

• Fuel gas and air inlets are modeled as mass flow inlet boundaries;

• Stack outlet is modeled as pressure outlet;

• One of the staged tips is considered as solid to account for the conjugate heat transfer from the fluid to solid region;

• Radiation coming from the flame is the primary heat source for the solid tip;

• The solid tip is provided with its riser to account for the flow effects from the fuel inlet to the tip;

• Excess air flow: 26.7% (to match 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 Ib/hr;

• Fuel flow rate per burner: 80.8 Ib/hr; and

• Heat release per burner: 1.62 MMBTU/hr.

[0048] Additionally, the modeled air composition and fuel gas composition are shown in Tables 1 and 2.

Table 1 Table 2

[0049] Thermal analysis was determined for the flame output for each case. The thermal results are summarized in Table 3.

Table 3

[0050] The result illustrated that all three designs resulted in similar flames from the nozzles. The mean CO iso-surface at 2000 parts per million volume dry (ppmvd) for cases 2 and 3 was within ±0.1 ft of the 6.3 ft for case 1. The floor and arch temperatures for cases 2 and 3 were within ±20 °F of case 1. Accordingly, the results are qualitatively the same for the three cases and the modifications made for case 3 did not affect the overall flame results.

[0051] An analysis of the calculated cross-sectional tangential velocity vectors within each nozzle was determined. For cases 1 and 2 the internal configuration of the nozzle (shown in FIG. 11) was of a standard tube and the tangential velocity vectors did not show a lot of mixing. The modified geometry of case 3 showed significant fluid mixing with recirculation zones going towards the nozzle center. Further, the results illustrated that the twisted interior of case 3 promoted breaking of thermal boundary and improved convection cooling as the fluid was continuously flushed from the walls of the nozzle interior.

[0052] Additionally, as illustrated in Table 3 above, there was no significant pressure drop between cases 1, 2 and 3 due to geometry modifications to case 3. The external surface temperatures were reduced for case 3 from those in cases 1 and 2, with portions of the nozzle body being reduced over about 100 °F. The interior tip surface temperatures in case 3 were likewise substantially reduced. Case 3 had the minimum peak to mean gas temperature difference, which shows a significant improvement in heat transfer resulting in overall cooler tip surfaces. The tip ports, primarily the ignition port and tip internal connection boundary, is where the coke formation is expected to start; however, case 3 showed approximately 280 °F temperature improvement over case 1 on these coke formation surfaces. Whereas, case 2 only showed a 70 °F improvement over case 1.

[0053] Accordingly, under the same simulation conditions, modifying the tip geometry in accordance with this disclosure did not affect the overall combustion results and did not result in any significant pressure drop within the nozzle. However, the nozzle design in accordance with this disclosure showed significant temperature and heat conduction conditions that would promote reduced coke formation.

[0054] Accordingly, the nozzles 20 described herein are an improvement over existing technology because conventional nozzles 20 have simply been devices used to inject fuel gas into a particular region of the burner with no consideration for heat transfer effects, flow profile or velocity. The current inventors have been the first to realize the advantages to be achieved by designing nozzles 20 with consideration for heat transfer effects, flow profile and/or velocity. Thus, the nozzles 20 of this disclosure address coking and plugging issues, which can be costly in terms of spare parts and labor.

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

[0056] Paragraph 1. A fuel nozzle for an industrial combustion system, the fuel nozzle comprising: an elongated body defining a fuel inlet port at a first end and terminating in tip at a second end, the elongated body having: an interior surface defining a bore extending longitudinally in the elongated body from the inlet port to the tip such that the interior surface has a longitudinally-extending portion and an interior-tip portion; at least one ridge defined on the longitudinally-extending portion of the inner surface; and an exterior surface having a side portion and an exterior-tip portion, wherein the tip defines a fuel port having an inner orifice at the interior-tip portion and an outer orifice at the exterior-tip portion; and wherein the inlet port, bore and inner orifice are in fluid flow communication so that at least a portion of fuel entering the inlet port flows through the bore, through the inner orifice and out the outer orifice. [0057] Paragraph 2. The fuel nozzle of paragraph 1, wherein the ridge is configured to create tangential flows of fuel passing through the bore to thus improve mixing.

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

[0059] Paragraph 4. The fuel nozzle of any preceding paragraph, further comprising an expansion chamber defined by the tip and in fluid flow communication with the bore and the inner orifice such that fuel in the bore flows into the expansion chamber prior to entering the inner orifice.

[0060] Paragraph 5. The fuel nozzle of any preceding paragraph, wherein the inner orifice has a beveled section.

[0061] Paragraph 6. The fuel nozzle of any preceding paragraph, wherein fuel port further defines a cavity located between the inner orifice and exterior orifice such that the cavity results in a pressure drop in fuel passing from the inner orifice to the exterior orifice.

[0062] Paragraph 7. The fuel nozzle of paragraph 6, wherein the inner orifice has a first diameter and exterior orifice has a second diameter, and the second diameter is greater than the first diameter.

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

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

[0065] Paragraph 10. The fuel nozzle of paragraph 8, wherein the insulating layer is formed by a shell separated from the exterior surface by a plurality of fins so as to form a plurality of air-pockets between the shell and the exterior surface.

[0066] Paragraph 11. The fuel nozzle of any of paragraphs 8 to 10, wherein the insulating layer is configured to create from about 50% to about 80% void zones, and optionally about 80% void zones.

[0067] Paragraph 12. A fuel nozzle for an industrial combustion system, the fuel nozzle comprising: an elongated body defining a fuel inlet port at a first end and terminating in a tip at a second end, the elongated body having: an interior surface defining a bore extending longitudinally in the elongated body from the inlet port to the tip such that the interior surface has a longitudinally-extending portion and an interior-tip portion; and an exterior surface having a side portion and an exterior-tip portion, wherein the burner tip defines a fuel port having an inner orifice at the interior-tip portion and an outer orifice at the exterior-tip portion; and an exterior insulating layer covering at least a portion of the side portion of the exterior surface; and wherein the inlet port, bore and inner orifice are in fluid flow communication so that at least a portion of fuel entering the inlet port flows through the bore, through the inner orifice and out the outer orifice.

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

[0069] Paragraph 14. The fuel nozzle of paragraph 12, wherein the insulating layer is formed by a shell separated from the exterior surface by a plurality of fins so as to form a plurality of air-pockets between the shell and the exterior surface.

[0070] Paragraph 15. The fuel nozzle of any of paragraphs 12 to 14, wherein the insulating layer is configured to create from about 50% to about 80% void zones, and optional about 80% void zones.

[0071] Paragraph 16. The fuel nozzle of any of paragraphs 12 to 15, wherein the inner orifice has a beveled section.

[0072] Paragraph 17. The fuel nozzle of any of paragraphs 12 to 16, wherein fuel port further defines a cavity located between the inner orifice and exterior orifice such that the cavity results in a pressure drop in fuel passing from the inner orifice to the exterior orifice.

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

[0074] Paragraph 19. The fuel nozzle of any of paragraphs 12 to 18, wherein the elongated body further comprises at least one ridge defined on the longitudinally-extending portion of the inner surface, and wherein the ridge is configured to create tangential flows of fuel passing through the bore to thus improve mixing [0075] Paragraph 20. The fuel nozzle of paragraph 19, wherein the ridge extends spirally along the longitudinally-extending portion of the interior 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 flow communication with the bore and the inner orifice such that fuel in the bore flows into the expansion chamber prior to entering the inner orifice.

[0077] While compositions and methods are described in terms of “comprising,” “containing,” or “including” various components or steps, the compositions and methods also can “consist essentially of’ or “consist of’ the various components and steps. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range are specifically disclosed. In particular, every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a-b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values. Additionally, where the term “about” is used in relation to a range it generally means plus or minus half the last significant figure of the range value, unless context indicates another definition of “about” applies.

[0078] Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. Moreover, the indefinite articles “a” or “an,” as used in the claims, are defined herein to mean one or more than one of the elements that it introduces. If there is any conflict in the usages 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 definitions that are consistent with this specification should be adopted.

Claims

WHAT IS CLAIMED IS:

1. A fuel nozzle for an industrial combustion system, the fuel nozzle comprising: an elongated body defining a fuel inlet port at a first end and terminating in tip at a second end, the elongated body having: an interior surface defining a bore extending longitudinally in the elongated body from the inlet port to the tip such that the interior surface has a longitudinally- extending portion and an interior-tip portion; at least one ridge defined on the longitudinally-extending portion of the inner surface; and an exterior surface having a side portion and an exterior-tip portion, wherein the tip defines a fuel port having an inner orifice at the interior-tip portion and an outer orifice at the exterior-tip portion; and wherein the inlet port, bore and inner orifice are in fluid flow communication so that at least a portion of fuel entering the inlet port flows through the bore, through the inner orifice and out the outer orifice.

2. The fuel nozzle of claim 1, wherein the ridge is configured to create tangential flows of fuel passing through the bore to thus improve mixing.

3. The fuel nozzle of claim 1, wherein the ridge extends spirally along the longitudinally-extending portion of the interior surface.

4. The fuel nozzle of claim 1, further comprising an expansion chamber defined by the tip and in fluid flow communication with the bore and the inner orifice such that fuel in the bore flows into the expansion chamber prior to entering the inner orifice.

5. The fuel nozzle of claim 1, wherein the inner orifice has a beveled section.

6. The fuel nozzle of claim 1, wherein the fuel port further defines a cavity located between the inner orifice and exterior orifice such that the cavity results in a pressure drop in fuel passing from the inner orifice to the exterior orifice.

7. The fuel nozzle of claim 6, wherein the inner orifice has a first diameter and exterior orifice has a second diameter, and the second diameter is greater than the first diameter.

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

9. The fuel nozzle of claim 8, wherein the insulating layer is formed by a lattice structure defining a plurality of pores.

10. The fuel nozzle of claim 8, wherein the insulating layer is formed by a shell separated from the exterior surface by a plurality of fins so as to form a plurality of air-pockets between the shell and the exterior surface.

11. The fuel nozzle of claim 8, wherein the insulating layer is configured to create from about 50% to about 80% void zones, and optionally about 80% void zones.

12. The fuel nozzle of any of claims 2 or 4- 11 , wherein the ridge extends spirally along the longitudinally-extending portion of the interior surface.

13. The fuel nozzle of any of claims 2-3 or 5-11, further comprising an expansion chamber defined by the tip and in fluid flow communication with the bore and the inner orifice such that fuel in the bore flows into the expansion chamber prior to entering the inner orifice.

14. The fuel nozzle of any of claims 2-4 or 6-11, wherein the inner orifice has a beveled section.

15. The fuel nozzle of any of claims 2-5 or 7-11, wherein the fuel port further defines a cavity located between the inner orifice and exterior orifice such that the cavity results in a pressure drop in fuel passing from the inner orifice to the exterior orifice.

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

17. The fuel nozzle of any of claims 10-11, wherein the insulating layer is configured to create from about 50% to about 80% void zones, and optionally about 80% void zones.

18. A fuel nozzle for an industrial combustion system, the fuel nozzle comprising: an elongated body defining a fuel inlet port at a first end and terminating in a tip at a second end, the elongated body having: an interior surface defining a bore extending longitudinally in the elongated body from the inlet port to the tip such that the interior surface has a longitudinally- extending portion and an interior-tip portion; and an exterior surface having a side portion and an exterior-tip portion, wherein the burner tip defines a fuel port having an inner orifice at the interior-tip portion and an outer orifice at the exterior-tip portion; and an exterior insulating layer covering at least a portion of the side portion of the exterior surface; and wherein the inlet port, bore and inner orifice are in fluid flow communication so that at least a portion of fuel entering the inlet port flows through the bore, through the inner orifice and out the outer orifice.

19. The fuel nozzle of claim 17, wherein the insulating layer is formed by a lattice structure defining a plurality of pores.

20. The fuel nozzle of claim 17, wherein the insulating layer is formed by a shell separated from the exterior surface by a plurality of fins so as to form a plurality of air-pockets between the shell and the exterior surface.

21. The fuel nozzle of claim 17, wherein the insulating layer is configured to create from about 50% to about 80% void zones, and optional about 80% void zones.

22. The fuel nozzle of claim 17, wherein the inner orifice has a beveled section.

23. The fuel nozzle of claim 17, wherein the fuel port further defines a cavity located between the inner orifice and exterior orifice such that the cavity results in a pressure drop in fuel passing from the inner orifice to the exterior orifice.

24. The fuel nozzle of claim 23, wherein the inner orifice has a first diameter and exterior orifice has a second diameter, and the second diameter is greater than the first diameter.

25. The fuel nozzle of claim 17, wherein the elongated body further comprises at least one ridge defined on the longitudinally-extending portion of the inner surface, and wherein the ridge is configured to create tangential flows of fuel passing through the bore to thus improve mixing.

26. The fuel nozzle of claim 25, wherein the ridge extends spirally along the longitudinally-extending portion of the interior surface.

27. The fuel nozzle of claim 26, further comprising an expansion chamber defined by the tip and in fluid flow communication with the bore and the inner orifice such that fuel in the bore flows into the expansion chamber prior to entering the inner orifice.

28. The fuel nozzle of claim 25, further comprising an expansion chamber defined by the tip and in fluid flow communication with the bore and the inner orifice such that fuel in the bore flows into the expansion chamber prior to entering the inner orifice.

29. The fuel nozzle of any of claims 18-22, wherein the fuel port further defines a cavity located between the inner orifice and exterior orifice such that the cavity results in a pressure drop in fuel passing from the inner orifice to the exterior orifice.

30. The fuel nozzle of any of claims 18-24, wherein the elongated body further comprises at least one ridge defined on the longitudinally-extending portion of the inner surface, and wherein the ridge is configured to create tangential flows of fuel passing through the bore to thus improve mixing.