Combustor and method of operation

Abstract

The present invention relates to particular burners, in particular non-premixed or partially premixed dual fuel burners with flexibility to change the heat input from two fuels. Thus, the combustor may be used in applications requiring the combustor to operate in both a single fuel mode and / or a dual fuel mode according to furnace operating requirements. The invention further relates to a furnace comprising said burner and a method of operating said burner.

Description

[0001] Cross-reference to related applications This application claims priority to U.S. nonprovisional application 18 / 233,419, filed August 14, 2023, which is incorporated herein by reference. Technical Field

[0002] This invention relates to burners, and more particularly to industrial burners for gaseous fuels, and especially to the field of multi-fuel (dual-fuel) burners. Background Technology

[0003] In the prior art, many high-temperature melting furnaces or preheating furnaces are designed to take into account air-fuel burners.

[0004] Due to increasing product or equipment operational demands, manufacturers are seeking burners—devices that provide energy to processes—that offer operational flexibility to the burner itself and, consequently, to the equipment. Furthermore, for dual-fuel burners, there is a need for a burner that can operate across a wide range of control ratios, equivalence ratios, and / or flexibility to select a portion of the heat supplied to the process from both fuels. Additionally, with increasing focus on alternative fuels and the availability of various gaseous fuels across different geographical locations, there is a need for a burner that can operate for a wide range of fuels with minimal or no changes to the burner hardware. Reliably starting / igniting a burner at low equivalence ratios (lean start) is particularly challenging, especially where airflow cannot be reduced below a specific setpoint and minimum fuel flow is required.

[0005] There are several potential approaches that can address these challenges.

[0006] First, fuel-flexible burners can be used, which can operate on any gaseous fuel, such as natural gas (“NG”), liquefied petroleum gas (“LPG”), biogas, syngas, hydrogen, ammonia, or other gases, and meet the emission and thermal performance standards of heating furnaces or melting furnaces. Designing fuel-flexible gaseous fuel burners presents several challenges, depending on the type and design of the burner. In addition to the wide variation in the combustion behavior of these fuels (well-documented in the combustion literature), differences in the calorific value, reaction rate, and flammability limits of gaseous fuels pose challenges in burner design.

[0007] Second, there is often a challenge in further optimizing the mixing of fuel and oxidizer in partially premixed combustors.

[0008] Third, there is a particular challenge in reducing flame length and achieving shorter flames that match the compact / short interior of reformers / furnaces / combustion chambers.

[0009] Fourth, a further overall goal in the burner sector is to maintain low NOx emissions.

[0010] Fifth, it is desirable to operate the burner for a wide range of primary and secondary fuel diversions.

[0011] Therefore, the first object of the present invention is to provide an advantageous burner that mitigates or overcomes one or more of the challenges described above.

[0012] The specific prior art design of the burner can be summarized as follows: US6019595 A discloses, for example, a burner having two combustion "mediums" (fuels), three coaxial tubes extending to different degrees, a core tube with an opening (hole) seal for radial flow, and an intermediate tube end.

[0013] CN111336515 A discloses, for example, a burner with three concentric tubes having three flows: two fuel flows and one air flow, but does not mention the nozzle design.

[0014] US 2014 / 0069079 A1 discloses, for example, a gas turbine combustor having alternating gas and air orifices, a swirling path, and two gases having a high (internal) and a low (external) BTU value.

[0015] US6835360 BB, for example, discloses a tube-in-tube reformer having a ring of tubes surrounding a radiant grid burner and a convection sleeve downstream of the burner. Summary of the Invention

[0016] This invention helps address the aforementioned challenges by providing a novel (non-premixed) multi-fuel (dual-fuel) burner.

[0017] In particular, the present invention provides a burner having a unique swirl-inducing nozzle, and a partially premixed main oxidant for a first fuel (e.g., an NG / LPG stream) and swirl blades for causing the main oxidant (e.g., air, oxygen, or a combination thereof) stream to swirl.

[0018] The burner of the present invention is believed to allow for more thorough mixing (e.g., from combined swirl and premixing orifices), resulting in a shorter flame matched within a compact / short reformer / furnace / combustion chamber.

[0019] Specifically, the present invention relates to the subject matter as defined in the claims.

[0020] Generally speaking, the burner of the present invention can be used, for example, in any application requiring high heating, particularly in applications such as steam methane reforming, reheating furnaces or secondary melting furnaces in the steel industry.

[0021] In general, the present invention provides a burner (1) including an ignition source (10); a primary fuel conduit (20) including a primary fuel outlet (22) having a plurality of primary fuel outlet holes (23) for supplying primary fuel to an ignition chamber (25), wherein the wall surrounding the ignition chamber (25) includes a plurality of bleed holes (28); a primary oxidizer conduit (30) for supplying a primary oxidizer, the primary oxidizer conduit including an intermediate annular conduit (35) in a downstream portion (5) of the burner, the intermediate annular conduit (35) being configured to allow diversion of the primary oxidizer such that a first portion is introduced into the ignition chamber (25) via the plurality of bleed holes (28) to mix with the primary fuel; and a secondary fuel conduit (40) for supplying secondary fuel, the secondary fuel conduit having a secondary fuel outlet (44) at its downstream end.

[0022] Preferably, at least in the downstream portion (5) of the burner (1), there are a primary fuel outlet (22), an ignition chamber (25), an intermediate annular conduit (35) and a secondary fuel outlet (44), the primary fuel conduit (20) being surrounded by a main oxidant conduit (30) and a secondary fuel conduit (40).

[0023] Furthermore, the present invention provides a furnace including the burner of the present invention, a method for operating the burner, and others.

[0024] The particular (further) advantages of the burner of the present invention are disclosed below. Attached Figure Description

[0025] The invention will now be described in conjunction with the accompanying drawings, wherein the same reference numerals denote the same elements.

[0026] Figure 1a is an exemplary side view of the downstream portion of an exemplary burner of the present invention, including its cross-section at the downstream end. It particularly shows the connection of the corresponding conduit and the preferred layout with a central axis.

[0027] Figure 1b is an exemplary side cross-sectional view of the downstream portion of an exemplary burner of the present invention. It particularly shows the connection of the corresponding conduit and the preferred layout with a central axis.

[0028] Figure 2a is an exemplary side cross-sectional view of the downstream portion of the burner of the present invention, indicating various (partially optional) components.

[0029] Figure 2b is an exemplary cross-sectional view of the downstream portion of the burner of the present invention, highlighting various components and optional components.

[0030] Figure 3a is an exemplary side cross-sectional view of the downstream portion of the burner of the present invention, highlighting certain distances, diameters, etc., such as the dimensions of various conduits (or pipes, accordingly), and certain distances between the outlet plane and the outlet.

[0031] Figure 3b provides an exemplary cross-sectional view of the burner (downstream portion) of the present invention, emphasizing the flow of certain components.

[0032] Figure 4 This is an exemplary cross-sectional view of the downstream portion of the burner of the present invention, emphasizing certain angles and distances, such as D0, which is the diameter of the primary fuel outlet orifice, and D1, which is the diameter of the purge orifice. It further illustrates how consecutive orifices in different rows can be staggered, with an stagger angle equal to half the angle between two consecutive orifices in a row.

[0033] Figure 5 A schematic diagram of a primary fuel conduit according to an embodiment of the invention is shown, emphasizing the optional layout of the discharge orifice (diameter P1) and indicating an optional air premixing orifice. It further indicates the angle α, the angle between the centers of two consecutive orifices measured at the center of the conduit.

[0034] Figure 6a is an exemplary side cross-sectional view of the downstream portion of the burner of the present invention, which, for example, emphasizes the flow and interaction of the primary fuel and the main oxidizer.

[0035] Figure 6b is a corresponding view of an embodiment that includes the aforementioned partial premixing as an optional feature. The air premixing orifice diverts a small portion of the primary air to the primary fuel line.

[0036] Figures 7a-c are exemplary cross-sectional views of alternative embodiments of the invention, which involve alternative types of (partial) premixing of primary fuel and main oxidant (e.g., air), such as using a “stepped design”.

[0037] Figure 8 Experimental results obtained using an exemplary burner of the present invention are shown.

[0038] Figure 9 The development of jets is illustrated and highlighted in the context of an exemplary burner of the present invention. Detailed Implementation

[0039] The present invention generally provides burners as defined in the claims and other subjects.

[0040] The burner of the present invention overcomes the challenges of the prior art in various ways as described above.

[0041] For example, this burner design enables rapid and thorough mixing of a portion of the air-fuel mixture at the ignition point. This is achieved through air entrainment in the fuel jet via a unique burner cup nozzle (ignition chamber) design, allowing for a lower peak temperature compared to the typical characteristics of non-premixed burners. The lower peak temperature contributes to reduced hot NOx formation compared to conventional non-premixed air-fuel combustion.

[0042] Furthermore, the burner can operate in a cold furnace (i.e., with an average temperature <400°F during the burner's start-up sequence) without requiring oxygen assistance or a continuous ignition source. The burner can operate even more stably in lean fuel, low flame temperature modes. The burner produces a stable flame (without any lift-off) over a very wide 30:1 turnout ratio range, even at equivalence ratios as low as 0.25. These characteristics enable the process furnace to be preheated at a controlled rate, allowing for process start-up and reaching steady-state conditions within the timeframe specified by process requirements.

[0043] This burner allows for starting / ignition at low equivalence ratios (lean fuel start), particularly when it is impossible to reduce the airflow rate below a specific setpoint while minimizing the start-up fuel flow for safety reasons. The equivalence ratio is defined as the ratio of the actual fuel / air molar ratio to the stoichiometric fuel / air molar ratio.

[0044] The burner allows the furnace to be operated within a wide range of the ratio of the total calorific value of the primary fuel to that of the secondary fuel (i.e., the combustion rate ratio).

[0045] Furthermore, the back pressure of the combustion aid (e.g., air) in the burner of the present invention eliminates the need for any external secondary compression devices for these flows. This feature helps reduce the operating costs of the burner and any maintenance associated with such activities.

[0046] In particular, in a first aspect of this document, a burner (1) is provided, the burner including an ignition source (10); a primary fuel conduit (20) including a primary fuel outlet (22) having a plurality of primary fuel outlet holes (23) for supplying primary fuel to an ignition chamber (25), wherein the wall surrounding the ignition chamber (25) includes a plurality of discharge holes (28); a main oxidizer conduit (30) for supplying a main oxidizer, the main oxidizer conduit including an intermediate annular conduit (35) in a downstream portion (5) of the burner, the intermediate annular conduit (35) The primary oxidizer is configured to allow diversion of the primary oxidizer, such that a first portion is introduced into the ignition chamber (25) via a plurality of discharge holes (28) to mix with the primary fuel; a secondary fuel conduit (40) for supplying secondary fuel has a secondary fuel outlet (44) at its downstream end, wherein at least in the downstream portion (5) of the burner (1), there are a primary fuel outlet (22), an ignition chamber (25), an intermediate annular conduit (35), and a secondary fuel outlet (44), the primary fuel conduit (20) being surrounded by the primary oxidizer conduit (30) and the secondary fuel conduit (40).

[0047] As used herein, the term "downstream portion of the burner" where "some outlets exist" refers to a downstream portion that includes all said outlets. Furthermore, said portion further includes a cyclone section and / or an exhaust port.

[0048] The term "downstream portion" may be used interchangeably with the term "downstream section" in this document.

[0049] In the preferred embodiment described herein, at least in the downstream portion (5) of the burner (1), there are a primary fuel outlet (22), an ignition chamber (25), an intermediate annular conduit (35), and a secondary fuel outlet (44), with the primary oxidizer conduit (30) and the secondary fuel conduit (40) arranged substantially concentrically around the primary fuel conduit (20).

[0050] In certain embodiments of the invention, one or more given conduits are arranged (concentrically) around one or more given other conduits, the conduits being arranged around another conduit for at least 20%, preferably at least 30%, particularly at least 40%, especially at least 50%, of the total length corresponding to the burner, and in some embodiments in at least 75% of a section, said section comprising a primary fuel outlet, a main oxidizer outlet, a secondary fuel outlet, and an auxiliary oxidizer outlet. Furthermore, where a swirler section and / or a bleed hole annulus are also present, said portion preferably further comprises a swirler section and / or a bleed hole annulus.

[0051] In this document, the “total length” of the burner of the present invention is determined by establishing the distance between the farthest upstream end of all conduits and the farthest downstream end of all conduits.

[0052] In another preferred embodiment, the primary fuel conduit, the main oxidizer conduit, and the secondary fuel conduit are arranged concentrically around the central ignition source along their entire length.

[0053] In a preferred embodiment of the invention, a given catheter is arranged concentrically around another catheter, resulting in the formation of a corresponding annulus.

[0054] Therefore, in the preferred embodiment herein, the burner is configured such that one or more fuels or oxidants flow through at least one annular space. In this invention, such annular spaces may also be characterized by including further elements (such as outlet orifices, exhaust orifices, swirler sections, etc.) of corresponding conduits as defined elsewhere herein.

[0055] Similarly, in a preferred embodiment herein, the burner is characterized in that one or more outlets of the duct are configured as annular rings. In this invention, such annular rings may be characterized by including further elements as defined elsewhere herein (such as outlet orifices, exhaust orifices, cyclone sections, etc.).

[0056] Typically, in this invention, if a catheter has a smaller diameter than other catheters and is arranged inside the other catheters, the catheter is described as being “surrounded” by the other catheter (or by several other catheters).

[0057] However, for a given conduit to be “surrounded” by another conduit, it is not necessary for the conduit to be completely surrounded by the other conduit, but rather it may extend further downstream and / or upstream from the other conduit. The corresponding definition applies herein when a given element is referred to as being arranged “surrounded” by another element.

[0058] In a preferred embodiment, the catheter described as being surrounded by other catheters shares its longitudinal axis with the other catheters.

[0059] In a preferred embodiment, the ignition chamber (25) extends from the primary fuel conduit outlet plane (55) to the intermediate annular conduit outlet plane (56).

[0060] In some preferred embodiments, the ignition chamber (25) is characterized by at least two (preferably two or three) steps in its walls, each step including a row of discharge holes (28).

[0061] In some preferred embodiments, the ignition chamber (25) includes a section having an outer diameter that is less than or equal to the inner diameter of the primary fuel conduit (20).

[0062] In some preferred embodiments, the ignition chamber (25) further includes a section having an inner diameter greater than the outer diameter of the primary fuel conduit (20), but an outer diameter smaller than the inner diameter of the intermediate annular conduit (35).

[0063] More specifically, in a particular set of embodiments, the burner is characterized in that the ignition chamber (25) extends from the primary fuel outlet (22) to the intermediate annular duct outlet plane (56), wherein the wall surrounding the ignition chamber (25) includes at least two (preferably two or three) steps of annular ducts with increasing diameters, each step including a plurality of discharge holes (28).

[0064] In another specific embodiment, the burner is characterized in that the ignition chamber (25) extends from the primary fuel outlet (22) to the intermediate annular conduit outlet plane (56), wherein the wall surrounding the ignition chamber (25) comprises two sections, wherein i) a first section extends from the primary fuel outlet (22) to the primary fuel conduit end plane (24), wherein the primary fuel conduit wall (29) surrounding this section comprises a plurality of discharge holes (28), and ii) a second section has an inner diameter greater than the outer diameter of the primary fuel conduit (20), but the second section has an outer diameter smaller than the inner diameter of the intermediate annular conduit (35), and includes Further multiple discharge ports (28), and wherein iii) the burner optionally further includes an air purge plate (73) having purge holes (32) extending between the outer diameter of the first section and the inner diameter of the second section, and iv) the burner optionally further includes two mechanical mixer plates (74), each mechanical mixer plate being positioned downstream of and adjacent to the two sections, and v) the burner optionally further includes a purge plate (73) having purge holes (32) existing between the outer diameter of the second section and the inner diameter of the intermediate annular duct (35).

[0065] Preferably, the mechanical mixer plate (74) has a disc-shaped structure that blocks the flow of fuel from the fuel outlet orifice (23). In particular, the first mechanical mixer plate has a disc-shaped structure (mechanical mixer 1) that blocks the flow of fuel from the fuel outlet orifice (23) of the "outer series". This disc blocks these fuel jets and helps the fuel and air mix rapidly in the ignition chamber.

[0066] Preferably, the purge plate (73) is a disc containing purge holes (32). More preferably, the plate / disc exists between the fuel conduit wall (29) and the intermediate conduit wall present inside the conduit (35).

[0067] In another specific embodiment, the burner is characterized in that the ignition chamber (25) extends from the primary fuel outlet (22) to the intermediate annular conduit outlet plane (56), wherein the wall surrounding the ignition chamber (25) comprises two sections, wherein i) the first section has an outer diameter smaller than the inner diameter of the primary fuel conduit (20) and includes a plurality of discharge holes (28), wherein the primary fuel conduit wall (29) surrounding the first section includes a plurality of discharge holes (28), and wherein the first section further includes provisions allowing the primary oxidant to additionally enter the ignition chamber in the flow direction between the two rings of primary fuel outlet holes. (25) the device, ii) the second section has an inner diameter greater than the outer diameter of the primary fuel conduit (20), but the second section has an outer diameter smaller than the inner diameter of the intermediate annular conduit (35), and includes a plurality of further discharge holes (28), and wherein the burner optionally further includes iii) a purge plate (73) having purge holes (32) between the outer diameter of the first section and the inner diameter of the second section, and iv) a purge plate (73) having purge holes (32) between the outer diameter of the second section and the inner diameter of the intermediate annular conduit (35).

[0068] Preferably, in this document, the ignition source (10) terminates in the ignition chamber (25).

[0069] In some implementations, the ignition source (10) is a central ignition source having a central axis (15) and a conduit end plane (16).

[0070] In the preferred embodiment of this invention, the main axis (2) of the burner (1) coincides with the central axis (15) of the ignition source (10).

[0071] Preferably, at least in the downstream portion (5) of the burner (1), the central ignition source (10) is connected by the primary fuel conduit (20), the main oxidizer conduit (30) and the secondary fuel conduit (40).

[0072] In some implementations, the main axis (2) of the burner (1) coincides with the central axis (15) of the ignition source (10).

[0073] Furthermore, regarding the ignition source (10), it can be designated as "pipe 1" in this document.

[0074] The (central) ignition source can also be referred to as the "igniter" in this article.

[0075] In this paper, the outer diameter of the ignition source (10) can be defined as D2.

[0076] Therefore, the central ignition source wall (19) can have an outer diameter D2.

[0077] Furthermore, the central ignition source is preferably arranged at the center of the burner, preferably along its entire length, and in particular, the remaining ducts of the burner are arranged concentrically around the central ignition source.

[0078] Furthermore, regarding the primary fuel conduit (20), which may be designated herein as “pipeline 2”, pipeline 2 is a gas fuel conduit.

[0079] In this paper, the inner diameter of the primary fuel conduit (20) can be defined as D3.

[0080] Therefore, the primary fuel conduit wall (29) can have an inner diameter D3.

[0081] In some embodiments, the end plane (24) of the primary fuel conduit corresponds to the end plane (26) of the ignition chamber.

[0082] The primary fuel conduit (20) further includes a primary fuel outlet (22). In some embodiments, the primary fuel outlet (22) is configured as a plate (72) including a primary fuel outlet orifice (23), and in particular as a fuel plate (72) including a primary fuel outlet orifice (23).

[0083] The primary fuel conduit (20) may further include a specific primary fuel connector (21).

[0084] In this document, the distance between the primary fuel outlet (22) and the primary fuel conduit end plane (24) and / or the ignition chamber end plane (26) can be defined as L0. Therefore, in some embodiments, the primary fuel outlet (22) is recessed by a distance L0 from the primary fuel conduit end plane (24) in the upstream direction. Preferably, the primary fuel conduit end plane (24) corresponds to the ignition chamber end plane (26).

[0085] In the burner described herein, the primary fuel conduit (20), more specifically the primary fuel outlet (22), further includes a primary fuel outlet orifice (23). Thus, the primary fuel outlet (22) may also be designated herein as a “fuel dispensing nozzle.” The outlet / nozzle may be described as having multiple orifices that introduce primary fuel into the ignition chamber.

[0086] In this paper, the diameter of the primary fuel outlet orifice (23) can be defined as D0. Preferably, D0 / D2 is between 0.04 and 0.5.

[0087] In a particular embodiment, the primary fuel outlet orifice (23) is positioned on concentric circles surrounding the center of the primary fuel outlet plate (72). Preferably, the total number of concentric circles is in the range of 2-7, more preferably, the total number of concentric circles is between 2-5. Preferably, the orifice is circular in shape. The orifice can be any other shape, such as star-shaped, triangular, double-star-shaped, rectangular, etc.

[0088] Without being bound by theory, such a size significantly contributes to the ability to rapidly mix fuel with the surrounding air.

[0089] In this paper, the circumferential angle defined by the main axis (2) of the burner and the center of the two adjacent primary fuel outlet holes (23) can be defined as angle θ.

[0090] In the burner described herein, the primary fuel conduit (20) further includes an exhaust port (28).

[0091] In this paper, the inner diameter of the discharge port (28) can be defined as P1. Preferably, P1 / D2 is between 0.05 and 0.4.

[0092] In a particular embodiment, the discharge holes (28) are arranged in rows around the primary fuel conduit. Preferably, there will be more than 5 rows of discharge holes; more preferably, no more than 3 rows of discharge holes. Preferably, the holes are circular in shape. The holes can be any other shape, such as star-shaped, triangular, double-star-shaped, rectangular, etc.

[0093] In this paper, the axial distance between the two rows of discharge holes (28), measured between their centers, can be defined as H.

[0094] In this paper, the circumferential angle determined by the main axis (2) of the burner and the center of the two adjacent exhaust holes (28) can be defined as angle α.

[0095] In a particular embodiment of this document, the primary fuel conduit (20) further includes an air premixing orifice (27) located upstream of the primary fuel outlet (22).

[0096] In this paper, the diameter of the air premixing hole (27) can be defined as P0. Preferably, P0 / D2 is between 0.02 and 0.2.

[0097] In a particular embodiment, air premixing orifices (27) are arranged in rows around the primary fuel conduit. Preferably, there will be no more than 5 rows of premixing orifices. More preferably, there will be no more than 3 rows of premixing orifices. Preferably, the orifices are circular in shape. The orifices can be any other shape, such as star-shaped, triangular, double-star-shaped, rectangular, etc.

[0098] In this paper, the distance between the primary fuel conduit wall (29) and the intermediate annular conduit wall (37) can be defined as L4.

[0099] Furthermore, regarding the main oxidant conduit (30), which may be designated herein as “pipe 3”, and specifically as an air conduit.

[0100] In this paper, the inner diameter of the main oxidant conduit (30) can be defined as D4.

[0101] Therefore, the main oxidant conduit wall (39) can have an inner diameter D4.

[0102] In this document, the distance between the end plane (36) of the intermediate annular conduit and the end plane (38) of the main oxidant conduit can be defined as L2. Therefore, in some embodiments, the end plane (36) of the intermediate annular conduit is recessed by a distance L2 from the end plane (38) of the main oxidant conduit in the upstream direction.

[0103] In the burner described herein, the main oxidizer conduit (30) further includes an intermediate annular conduit (35).

[0104] In this invention, the intermediate annular conduit (35) is configured to allow the main oxidant to be diverted into two portions, such that the first portion is introduced into the ignition chamber (25) via a plurality of discharge holes (28) as defined above.

[0105] The first portion is preferably about 20% of the total volumetric flow rate. In a particular embodiment, the first portion is in the range of 2% to 40%, preferably in the range of 10% to 25%.

[0106] In a preferred embodiment described herein, a first portion of the primary oxidant enters the ignition chamber at a right angle to the primary fuel outlet (via the circumferential wall of the chamber).

[0107] Therefore, in the preferred embodiment of this document, the first portion of the primary oxidant enters the ignition chamber in a direction perpendicular to the flow direction of the primary fuel.

[0108] Without being bound by theory, this is used to violently mix the fuel and "ignition" air, resulting in a lower peak flame temperature compared to a typical diffuse flame. This is considered important for minimizing NOx emissions from the flame. Furthermore, the air introduction method also keeps the circumferential walls cooled by preventing them from direct contact with the flame.

[0109] In this document, the distance between the primary fuel conduit end plane (24) and the intermediate annular conduit end plane (36) can be defined as L1. Therefore, in some embodiments, the primary fuel conduit end plane (24) is recessed by a distance L1 from the intermediate annular conduit end plane (36) in the upstream direction.

[0110] In a preferred embodiment of the invention, the burner is characterized in that the main oxidant conduit (30) further includes a cyclone section (33).

[0111] Therefore, the intermediate annular conduit (35) is preferably configured to allow the main oxidant to be diverted into two parts, wherein the second part is introduced into the hydrocyclone section (33).

[0112] In particular, in a preferred embodiment herein, the annular conduit (35) is configured to allow the main oxidant to be diverted into two portions, such that a first portion is introduced into the ignition chamber (25) via a plurality of discharge holes (28) to mix with the primary fuel, and a second portion is introduced into a cyclone section (33) which further includes the main oxidant conduit.

[0113] Without being bound by theory, the second portion of air introduced into the cyclone section causes a strong tangential flow field in the combustion chamber, which increases the mixing rate between the oxidizer and fuel, while also producing a compact flame and a flame that does not contain significant soot.

[0114] Furthermore, without being bound by theory, the use of swirl generators to create air swirl is well-known in the field of combustion. The primary function of the swirl is to provide a tangential flow to, for example, the air exiting duct 3, and to create a recirculation zone at the center that carries hot combustion gases back to the burner outlet plane, thus providing a continuous ignition source for fresh reactants. The upper and lower limits of the swirl angle are determined by the length of the furnace and the combustion rate of the burner.

[0115] Preferably, the swirl angle is 5 to 60 degrees, more preferably 30 to 45 degrees.

[0116] As used in this article, the “swirling angle” is defined as the angle between a plane nominally tangent to the outlet of the swirler blades and a plane parallel to the main axis of the burner.

[0117] Preferably, in this document, the number of swirls (defined herein as the ratio of the axial flux of tangential momentum to the axial flux of axial momentum) is in the range of 0.1 to 1.5.

[0118] In some embodiments, the main oxidant conduit (30) further includes a purge port (32) positioned on an air purge plate (73), particularly in the flow direction parallel to the main axis (2) of the burner.

[0119] In this paper, the diameter of the purge hole (32) can be defined as D1. Preferably, D1 / D2 is between 0.04 and 0.5.

[0120] In a particular embodiment, the purge holes (32) are arranged in a circular pattern on different concentric diameters, such as 1-7 rows, preferably 1-3 holes of concentric diameters. Preferably, the holes are circular in shape. The holes can be any other shape, such as star-shaped, triangular, double-star-shaped, rectangular, etc.

[0121] In this paper, the circumferential angle defined by the main axis (2) of the burner and the center of the two adjacent purge holes (32) can be defined as angle β.

[0122] The main oxidant conduit (30) may further include a specific main oxidant connector (31).

[0123] Furthermore, regarding the secondary fuel conduit (40), which may be designated herein as “pipeline 4”, pipeline 4 is a gas fuel conduit.

[0124] In this paper, the inner diameter of the secondary fuel conduit (40) can be defined as D5.

[0125] Therefore, the secondary fuel conduit wall (49) can have an inner diameter D5.

[0126] In some embodiments, the burner (1) further includes a turbulence generator (47) in a secondary fuel conduit (40).

[0127] The turbulence generator may also be referred to herein as a device for generating turbulence or a turbulence generator device. It may comprise one or more turbulence generator discs or turbulence generator plates. Preferably, the turbulence generator device is arranged on an additional wall of the secondary fuel conduit, which is positioned adjacent to the wall of the main oxidizer conduit.

[0128] In some embodiments, the burner further includes swirl vanes in a secondary fuel duct.

[0129] In this document, the distance between the end plane (38) of the primary oxidizer conduit and the end plane (46) of the secondary fuel conduit can be defined as L3. Therefore, in some embodiments, the end plane (38) of the primary oxidizer conduit is recessed by a distance L3 from the end plane (46) of the secondary fuel conduit in the upstream direction.

[0130] The burner of the present invention is designed to operate using any gaseous fuel, such as natural gas (NG), hydrogen (H2), LPG, biogas, syngas, hydrogen, ammonia or other gases.

[0131] Therefore, according to the present invention, the primary fuel used in the burner is any gaseous fuel. In a preferred embodiment, it is selected from the group consisting of NG, H2, and LPG.

[0132] According to the present invention, the secondary fuel is any gaseous fuel. In a preferred embodiment, the secondary fuel is exhaust gas. In a preferred embodiment, the secondary fuel is selected from the group consisting of PSA exhaust gas, syngas, and a mixture of H2 / CO / CO2 / CH4.

[0133] Generally, there are no particular limitations on the specific properties of the fuel and oxidant to be used with the burner of the present invention. Furthermore, in some embodiments, the material flowing through a particular conduit (e.g., fuel or oxidant) may be replaced with the same or different material (e.g., oxidant or fuel) as disclosed above. For example, a secondary oxidant may be used instead of the secondary fuel in the burner (1). In this particular embodiment, fuel flows through the primary fuel conduit (20) of the burner (1), while the oxidant flows through the main oxidant conduit (30) and the secondary fuel conduit (40). Alternatively, in some embodiments, a secondary fuel may be used instead of the main oxidant. In this embodiment, fuel flows through the primary fuel conduit (20) and the main oxidant conduit (30) of the burner (1), while the oxidant or fuel flows through the secondary fuel conduit (40). In other words, any combination of fuel or oxidant may flow through the primary fuel conduit (20), the main oxidant conduit (30), and the secondary fuel conduit (40) of the burner (1).

[0134] As used herein, the “outlet plane” of a given conduit refers to a plane defined in a direction perpendicular to the main axis of the conduit at a downstream location where the fuel or oxidant is no longer confined by the two walls respectively.

[0135] As used herein, the “catheter end plane” of a given catheter refers to a plane defined at the downstream end of the catheter in a direction perpendicular to the main axis of the catheter.

[0136] In the preferred embodiments described herein, D3 / D2 is 1.5 to 4.5, particularly 2.0 to 3.0.

[0137] In the preferred embodiment described herein, D4 / D2 is 3.0 to 9.0, particularly 3.5 to 5.5.

[0138] In the preferred embodiments described herein, D5 / D2 is 5.0 to 11.0, particularly 5.5 to 7.0.

[0139] In the preferred embodiment described herein, L1 / L4 is 0.5 to 2.5, particularly 1.0 to 2.0.

[0140] In the preferred embodiment described herein, L0 / D3 is 0.25 to 1.0, particularly 0.4 to 0.6.

[0141] In the preferred embodiment described herein, (L1+L2) / D3 is 0.25 to 1.0, particularly 0.4 to 0.6.

[0142] In the preferred embodiment described herein, L3 / D4 is 0.05 to 0.25, particularly 0.1 to 0.2.

[0143] In the preferred embodiment described herein, H / P1 is 1.25 to 2.5.

[0144] In the preferred embodiment described herein, the angle α is 3 to 30 degrees, such as 10 to 20 degrees. The ratio of the area of ​​all discharge holes in a row to the surface area of ​​the cylinder with height P1 and inner diameter D2 is between 10% and 55%.

[0145] Without being bound by theory, the lower limit of angle α helps to separate the orifices so that they are not too close to interfere with the mixing of fuel and air, and the upper limit of angle α prevents the orifices from being too far apart and ensures sufficient fluid communication between adjacent jets to enhance fuel-air mixing and ignition in the ignition chamber.

[0146] Each row can be symmetrically staggered to provide a three-dimensional mixing effect. This mixing is crucial for providing reliable ignition of the burner at lean equivalence ratios as low as 0.25.

[0147] In the preferred embodiment described herein, the angle β is 5 to 40 degrees.

[0148] In a preferred embodiment, the air purge plate (73) has a porosity in the range of 2% to 15% (defined by dividing the total open area on the plate that allows airflow by the cross-sectional area of ​​the plate).

[0149] Without being bound by theory, the lower limit of angle β helps to separate the orifices so they are not too close together, creating air-rich regions, while the upper limit of angle β prevents the orifices from being too far apart, ensuring sufficient fluid communication between adjacent jets to provide each other with chemically active flame radicals that support ignition and thus enhance flame stability. Sufficient air is used for fuel-air mixing and to create low-velocity and recirculation zones to provide a flame anchoring zone. This flame anchoring position is critical for preventing flame extinction, for example, in extreme cases such as when primary fuel is reduced to 10% of the burner's maximum combustion rating and secondary fuel is cut off / shut down.

[0150] In some embodiments, the burner includes different rows of holes, and consecutive holes in different rows are staggered by half the included angle between two consecutive holes in a row.

[0151] In the preferred embodiment described herein, the angle θ is 10 to 40 degrees.

[0152] In a preferred embodiment, the primary fuel outlet plate (72) has a porosity in the range of 2% to 25% (determined by dividing the total open area on the plate that allows fuel flow by the cross-sectional area of ​​the plate).

[0153] Without being bound by theory, the lower limit of the angle θ helps to separate the orifices so that they are not too close to prevent air entrainment in the fuel jets when the two fuel jets become too close, and the upper limit of the angle θ prevents the orifices from being too far apart and ensures that there is sufficient coupling between the two jets to provide a stable flame over the entire wide range of the control ratio and equivalence ratio.

[0154] In some embodiments, the burner includes different rows of holes, and consecutive holes in different rows are staggered by half the included angle between two consecutive holes in a row.

[0155] In a preferred embodiment, the burner (1) is configured such that the velocity of the primary fuel at the outlet of the primary fuel outlet orifice (23) is between 30 feet / second and 500 feet / second, particularly between 40 feet / second and 400 feet / second.

[0156] Without being bound by theory, determining the primary fuel velocity significantly contributes to the fuel's ability to mix rapidly with the surrounding air. This velocity range provides a stable flame without any flameout.

[0157] In a preferred embodiment, the burner (1) is configured such that the velocity of the primary oxidant at the outlet of the combustion aid duct (34) is between 5 feet / second and 300 feet / second, particularly between 10 feet / second and 200 feet / second.

[0158] Without being bound by theory, the maximum achievable primary oxidant (preferably air) velocity is typically determined by the available pressure from the blower. The inventors have found that these velocities, along with appropriate swirl angles, provide adequate mixing of the air with both fuels and maintain a stable flame over a wide range of burner operations, even in cold furnaces.

[0159] In a preferred embodiment, the burner (1) is configured such that the velocity of the secondary fuel is between 20 feet per second and 200 feet per second, particularly between 40 feet per second and 120 feet per second.

[0160] Without being bound by theory, the velocity of the secondary fuel is determined such that it provides sufficient mixing with the swirling air, thereby enabling a stable flame. Secondary fuel velocities below low velocity limits may cause unreacted fuel to accumulate near the furnace wall. This fuel can then burn there, leading to overheating of the reformer top wall.

[0161] In a preferred embodiment, the burner of the present invention operates in such a manner that: i) During startup, approximately 100% of the burner's total thermal power (defined as the sum of the products of the calorific value (higher or lower) and flow rate of each fuel) is provided by the primary fuel; and / or ii) During normal operation, approximately 5% to 70%, preferably 45% to 65%, of the total thermal power of the burner is supplied by primary fuel, and the corresponding remainder is supplied by secondary fuel.

[0162] The corresponding remaining portion is preferably supplied by secondary fuel.

[0163] In a preferred embodiment, the burner is configured such that i) the volumetric flow rate of the oxidant in the ignition chamber is about 5% to 25% of the total main oxidant flow rate; and / or ii) the volumetric flow rate of the premixed oxidant is about 2% to 10% of the total main oxidant flow rate. In a particular conduit, the volumetric flow rate of any fluid is divided between different outlets by relating the individual outlet cross-sectional area of ​​that conduit to the total outlet cross-sectional area. In doing so, the fluid pressure and the pressure difference between two adjacent conduits are important criteria for determining the directional flow of the fluid. For example, Figure 6B Exemplary area symbols for the combustion-supporting agent conduit are shown. The cross-sectional areas of the discharge port (28), air purging port (32), cyclone section outlet (34), and premixing port (27) are A0, A1, A2, and A3, respectively.

[0164] A0 = 5% to 25% of (A0+A1+A2+A3).

[0165] A3 = 2% to 10% of (A0+A1+A2+A3).

[0166] Therefore, in the preferred embodiment of this document, the cross-sectional areas of the discharge port (28), the air purging port (32), the cyclone section outlet (34), and the premixing port (27) are A0, A1, A2, and A3, where A0 = 5% to 25% of (A0+A1+A2+A3).

[0167] Similarly, in the preferred embodiment of this document, the cross-sectional areas of the discharge port (28), the air purging port (32), the cyclone section outlet (34), and the premixing port (27) are A0, A1, A2, and A3, respectively, where A3 = 2% to 10% of (A0+A1+A2+A3).

[0168] Preferably, in this document, the secondary fuel conduit (40) is close to the primary oxidizer conduit (30), wherein D5 / D4 is preferably between 1.05 and 1.40, and more preferably between 1.1 and 1.25. This allows for the initiation of the flow of the secondary fuel and ignition by heat from the primary fuel flame (which acts as an ignition flame for the secondary fuel), without requiring a furnace temperature higher than the auto-ignition temperature of the secondary fuel and / or without requiring an ignition source to ignite the secondary fuel.

[0169] Further specific embodiments of the present invention are described in the accompanying drawings, which can be further described in detail below: For example, as indicated in Figure 6a, a portion of the primary air (typically 2%–40% of the total, preferably 10%–25%, such as about 20%) is introduced into the ignition chamber via the circumferential wall of the chamber, which is perpendicular to the fuel distribution nozzle. This is used to vigorously mix the fuel and the “ignition” air so that ignition can reliably and repeatedly occur in a gas mixture within the combustible range of fuel concentration, while also allowing the peak flame temperature to be reduced compared to a typical diffuse flame. This is considered important for minimizing NOx emissions from the flame. Furthermore, the method of air introduction also keeps the circumferential wall cooled by preventing it from direct contact with the flame. The fuel distribution plate (72) (the term may be used interchangeably herein with “primary fuel outlet plate”) is recessed by a length of L0+L1 to provide more length for the fuel jet to develop partially or completely and to be partially premixed with the “ignition cup” air.

[0170] For example, as indicated in Figure 6b, the air premixing orifice (27) enables fluid communication between the primary air and the primary fuel upstream of the fuel distribution plate (72). These orifices (number and diameter of the orifices, number of rows of orifices) can be predetermined based on the ratio of the area of ​​orifice A3 to the swirling air outlet area, as well as the pressures of the air and the primary fuel. The pre-calculated ratio depends on the amount of air required in the primary fuel during startup.

[0171] Generally speaking, the advantageous features of the invention herein include the following, all of which correspond to other preferred embodiments of the first aspect: – The first aspect of the burner is characterized by providing an improved mixture of primary oxidizer and primary fuel.

[0172] – The first aspect of the burner is characterized by providing an improved partial premixing of the primary oxidizer and the primary fuel.

[0173] –The burner of the first aspect is characterized by a reduced flame length.

[0174] – A characteristic of the burner in the first aspect is that it is fuel-flexible (and, for example, allows the use of NG, H2, LPG and low Btu secondary fuels). It allows for reliable start-up in cold furnaces (below the auto-ignition temperature of the fuel) using an air-fuel mode.

[0175] – The characteristic of the burner in the first aspect is that it does not require water cooling.

[0176] – The first aspect of the burner can be characterized by allowing low NOx levels, for example, keeping NOx levels within environmental limits.

[0177] – The characteristic of the burner in the first aspect is that it can operate in an air-fuel mode, regardless of the average temperature of the furnace.

[0178] – The first aspect of the burner's characteristics can be achieved with an adjustment ratio of 1:30.

[0179] – The burner of the first aspect is characterized by a lean fuel-stabilized flame under high excess air (equivalence ratio as low as 0.25) without flame extinction, and in primary fuel mode, the burner continues to operate when the primary fuel is reduced to 10% of the burner’s maximum combustion rating and the secondary fuel is cut off.

[0180] – The characteristic of the burner in the first aspect is that it can achieve stable and reliable ignition and combustion under cold furnace conditions with an equivalence ratio as low as 0.25.

[0181] – The first aspect of the burner's characteristics lies in the flexibility of its operation across a wide range of total heat / energy distributions from primary and secondary fuels. This includes approximately 5% to 100% of the total heat output from the primary fuel and the remainder from the secondary fuel.

[0182] – The characteristic of the burner in the first aspect is that it produces a compact flame (flame length / D3 < 20) (see...) Figure 8 ).

[0183] In a second aspect of the invention, a furnace is provided that includes a burner according to a first aspect of the invention.

[0184] The preferred embodiment of the furnace of the present invention corresponds to the embodiment of the burner of the present invention described above. Therefore, preferably, the furnace is further defined with reference to any of the above-described embodiments of the burner as described in the context of the first aspect.

[0185] This includes embodiments related to the advantages of the burner described above in the first aspect, which are also conceived herein with respect to the corresponding furnace in the second aspect.

[0186] In some preferred embodiments, the furnace is selected from the group consisting of furnaces used for steam methane reforming, reheating furnaces in the steel industry, and secondary melting furnaces.

[0187] In a third aspect of the invention, a method is provided for operating a burner of the first aspect and / or for operating a furnace of the second aspect.

[0188] The method is not particularly limited, as will be readily understood by those skilled in the art.

[0189] In some implementations, the method includes the following steps: i) starting the burner, ii) ramping up the combustion rate of the burner, iii) starting the secondary fuel, and iv) further changing the flow rates of the primary fuel and secondary fuel and the equivalence ratio of the burner according to process requirements.

[0190] In a specific implementation of the third aspect, step i) includes starting the main oxidizer, igniter, and primary fuel.

[0191] Generally, a further preferred embodiment of the method of the present invention corresponds to an embodiment of the burner of the present invention described above, wherein the burner used in the method is further defined by further product features. In other words, preferably, the method of the present invention is further defined with reference to any of the above-described embodiments of the burner as described in the context of the first aspect.

[0192] Furthermore, even more preferred embodiments of the method of the present invention involve further method features based on any features described above in the context of the burner of the present invention.

[0193] Furthermore, the advantages of the present invention include the following, all of which correspond to a further preferred embodiment of the third aspect: – The third aspect of the method is characterized by providing an improved blend of primary oxidant and primary fuel.

[0194] – The third aspect of the method is characterized by providing an improved partial premixing of the primary oxidant and the primary fuel.

[0195] – The third aspect of the method is characterized by a reduction in flame length.

[0196] – A third aspect of this approach is that it is fuel-flexible (and, for example, allows the use of NG fuel). It allows for reliable startup in cold furnaces (below the auto-ignition temperature of the fuel) using an air-fuel configuration.

[0197] – A characteristic of the third method is that it does not require water cooling.

[0198] – A third aspect of the approach is that it allows for keeping NOx levels low, for example, keeping NOx levels within environmental limits.

[0199] – The third aspect of the method is characterized by the low back pressure of the combustion air eliminating the need for any secondary compression device.

[0200] – The third aspect of the method is characterized by the fact that it can operate in an air-fuel mode, regardless of the average temperature of the furnace.

[0201] Furthermore, generally speaking, in this document, a preferred embodiment of any one of the second to fourth aspects corresponds to a preferred embodiment of the first aspect.

[0202] Generally, when applied to any feature in embodiments of the invention described in the specification and claims, the article “a / an” as used herein means one or more. The use of “a / an” does not limit the meaning to a single feature unless such a limitation is specifically stated. The article “the” preceding a singular or plural noun or noun phrase indicates one or more specific designated features and may have a singular or plural meaning depending on the context in which it is used. The adjective “any” means one, some, or all, regardless of quantity.

[0203] Furthermore, in general, if an embodiment is described herein using the term "comprising" or similar terms, other embodiments are also contemplated herein, which are described using the term "consisting of" or similar terms instead of the term "comprising" or similar terms.

[0204] Other specific implementation schemes This invention also specifically relates to the following items: Item 1: A burner (1) comprising: Ignition source (10). A primary fuel conduit (20) includes a primary fuel outlet (22) having a plurality of primary fuel outlet holes (23) for supplying primary fuel to an ignition chamber (25), wherein the wall surrounding the ignition chamber (25) includes a plurality of discharge holes (28). A main oxidizer conduit (30) for supplying the main oxidizer, the main oxidizer conduit including an intermediate annular conduit (35) in the downstream portion (5) of the burner, the intermediate annular conduit (35) being configured to allow diversion of the main oxidizer such that a first portion is introduced into the ignition chamber (25) via the plurality of discharge holes (28) to mix with the primary fuel; A secondary fuel conduit (40) for supplying secondary fuel, the secondary fuel conduit having a secondary fuel outlet (44) at its downstream end.

[0205] Item 2: The burner according to Item 1, wherein at least in the downstream portion (5) of the burner (1), there is a primary fuel outlet (22), an ignition chamber (25), an intermediate annular conduit (35), and a secondary fuel outlet (44), the primary fuel conduit (20) being surrounded by the main oxidant conduit (30) and the secondary fuel conduit (40).

[0206] Item 3: The burner according to Item 1 or 2, wherein the ignition chamber (25) is located within the primary fuel conduit (20) and extends from the primary fuel outlet (22) to the end plane (24) of the primary fuel conduit, wherein the primary fuel conduit wall (29) surrounds the ignition chamber (25) and includes a plurality of discharge holes (28).

[0207] Item 4 (see example) Figure 7A): The burner according to item 1 or 2, wherein the ignition chamber (25) extends from the primary fuel outlet (22) to the intermediate annular conduit outlet plane (56), wherein the wall surrounding the ignition chamber (25) comprises at least two (preferably two or three) steps of annular conduits with increasing diameters, each step comprising a plurality of discharge holes (28).

[0208] Item 5 (see example) Figure 7B ): The burner according to item 1 or 2, wherein the ignition chamber (25) extends from the primary fuel outlet (22) to the intermediate annular conduit outlet plane (56), wherein the wall surrounding the ignition chamber (25) comprises two sections, wherein i) a first section extends from the primary fuel outlet (22) to the primary fuel conduit end plane (24), wherein the primary fuel conduit wall (29) surrounding the section comprises a plurality of discharge holes (28), and ii) a second section has an inner diameter greater than the outer diameter of the primary fuel conduit (20), but the second section has an outer diameter smaller than the inner diameter of the intermediate annular conduit (35), and comprises a further plurality of discharge holes (28), optionally wherein the burner further comprises iii) an air purge plate (73) having purge holes (32) extending between the outer diameter of the first section and the inner diameter of the second section, and iv) two mechanical mixer plates (74), each mechanical mixer plate being positioned downstream of and adjacent to the two sections.

[0209] Item 6 (see example) Figure 7C ): The burner according to item 1 or 2, wherein the ignition chamber (25) extends from the primary fuel outlet (22) to the intermediate annular conduit outlet plane (56), wherein the wall surrounding the ignition chamber (25) comprises two sections, wherein i) the first section has an outer diameter smaller than the inner diameter of the primary fuel conduit (20) and includes a plurality of discharge holes (28), wherein the primary fuel conduit wall (29) surrounding the first section includes a plurality of discharge holes (28), and wherein the first section further includes means for allowing the primary oxidant to enter the ignition chamber (25) in the flow direction between the two primary fuel outlet holes, and ii) the second section has an inner diameter larger than the outer diameter of the primary fuel conduit (20), but the second section has an outer diameter smaller than the inner diameter of the intermediate annular conduit (35) and includes a plurality of additional discharge holes (28).

[0210] Item 7: A burner according to any one of the preceding items, wherein the ignition source (10) terminates in the ignition chamber (25), in particular, wherein the ignition source (10) is a central ignition source having a central axis (15) and a conduit end plane (16), in particular, wherein the main axis (2) of the burner (1) coincides with the central axis (15) of the ignition source (10), in particular, wherein at least in the downstream portion (5) of the burner (1), the central ignition source (10) is surrounded by the primary fuel conduit (20), the main oxidant conduit (30) and the secondary fuel conduit (40).

[0211] Item 8: The burner according to any one of the preceding items, i) The end plane (24) of the primary fuel conduit corresponds to the end plane (26) of the ignition chamber; and / or ii) The primary fuel conduit further includes an air premixing orifice (27) upstream of the primary fuel outlet (22); and / or iii) The main oxidant conduit (30) further includes purge holes (32) in a flow direction parallel to the main axis (2) of the burner; and / or iv) The main oxidant conduit (30) further includes a hydrocyclone section (33), specifically, wherein the intermediate annular conduit (35) is configured to allow the main oxidant to be diverted into two portions, wherein a second portion is introduced into the hydrocyclone section (33); and / or v) The burner (1) further includes a turbulence generator (47) in the secondary fuel conduit (40).

[0212] Item 9: A burner according to any one of the preceding items, wherein the main oxidant conduit (30) further includes a cyclone section (33), and in particular, wherein the intermediate annular conduit (35) is configured to allow the main oxidant to be diverted into two portions, wherein the second portion is introduced into the cyclone section (33).

[0213] Item 10: A burner according to any one of the preceding items, wherein the burner (1) further comprises a turbulence generator (47) in the secondary fuel conduit (40).

[0214] Item 11: A burner according to any of the preceding items, wherein the primary fuel conduit end plane (24) corresponds to the ignition chamber end plane (26).

[0215] Item 12: The burner according to any one of the preceding items, wherein the primary fuel conduit further includes an air premixing orifice (27) upstream of the primary fuel outlet (22).

[0216] Item 13: A burner according to any one of the preceding items, wherein the main oxidant conduit (30) further includes a purge hole (32) in a flow direction parallel to the main axis (2) of the burner.

[0217] Item 14: A burner according to any one of the preceding items, wherein the main oxidant conduit (30) further includes a cyclone section (33), and in particular, wherein the intermediate annular conduit (35) is configured to allow the main oxidant to be diverted into two portions, wherein the second portion is introduced into the cyclone section (33).

[0218] Item 15: A burner according to any one of the preceding items, wherein the burner (1) further comprises a turbulence generator (47) in the secondary fuel conduit (40), and in particular, wherein the turbulence generator comprises one or more turbulence generator discs.

[0219] Item 16: A burner according to any one of the preceding items, wherein: i) The diameter of the primary fuel outlet orifice (23) is defined as D0, where D0 / D2 is between 0.04 and 1.00; and / or ii) The diameter of the purge hole (32) is defined as D1, where D1 / D2 is between 0.04 and 0.5; and / or iii) The outer diameter of the ignition source (10) is defined as D2, and the inner diameter of the primary fuel conduit (20) is defined as D3, wherein D3 / D2 is 1.5 to 4.5, particularly 2.0 to 3.0; and / or iv) The outer diameter of the ignition source (10) is defined as D2, and the inner diameter of the main oxidant conduit (30) is defined as D4, wherein D4 / D2 is 3.0 to 9.0, particularly 3.5 to 5.5; and / or v) The outer diameter of the ignition source (10) is defined as D2, and the inner diameter of the secondary fuel conduit (40) is defined as D5, wherein D5 / D2 is 5.0 to 11.0, particularly 5.5 to 7.0; and / or vi) The diameter of the air premixing orifice (27) is defined as P0, where P0 / D2 is between 0.02 and 0.2, particularly between 0.05 and 0.2; and / or vii) The inner diameter of the discharge port (28) is defined as P1, where P1 / D2 is between 0.05 and 0.4; and / or iiix) The distance between the end plane (24) of the primary fuel conduit and the end plane (36) of the intermediate annular conduit is defined as L1, and the distance between the wall of the primary fuel conduit (29) and the wall of the intermediate annular conduit (37) is defined as L4, wherein L1 / L4 is 0.5 to 2.5, particularly 1.0 to 2.0; and / or ix) The distance between the end plane (24) of the primary fuel conduit and the end plane (36) of the intermediate annular conduit is defined as L1, the distance between the end plane (36) of the intermediate annular conduit and the end plane (38) of the main oxidant conduit is defined as L2, and the inner diameter of the primary fuel conduit (20) is defined as D3, wherein (L1+L2) / D3 is 0.25 to 1.0, particularly 0.4 to 0.6; and / or x) The distance between the end plane (38) of the main oxidizer conduit and the end plane (46) of the secondary fuel conduit is defined as L3, and the inner diameter of the main oxidizer conduit (30) is defined as D4, wherein L3 / D4 is 0.05 to 0.25, particularly 0.1 to 0.2; and / or xi) The distance between the primary fuel outlet (22) and the end plane (24) of the primary fuel conduit and / or the end plane (26) of the ignition chamber is defined as L0, and the inner diameter of the primary fuel conduit (20) is defined as D3, wherein L0 / D3 is 0.25 to 1.0, particularly 0.4 to 0.6; and / or xii) The distance between the two rows of discharge holes (28), measured between their centers, is defined as H, and the inner diameter of the discharge holes (28) is defined as P1, where H / P1 is 1.25 to 2.5; and / or xiii) The angle defined by the main axis (2) of the burner and the center of two adjacent exhaust holes (28) is defined as angle α, where angle α is 3 to 30 degrees; and / or xiv) The angle defined by the main axis (2) of the burner and the centers of two adjacent purge holes (32) is defined as angle β, wherein angle β is between 5 and 40 degrees; and / or The angle defined by the center of the main axis (2) of the burner and the two adjacent primary fuel outlet holes (23) is defined as angle θ, where angle θ is 10 to 40 degrees.

[0220] Item 17: The burner according to any one of the preceding items, wherein the diameter of the primary fuel outlet orifice (23) is defined as D0, wherein D0 / D2 is between 0.04 and 0.5.

[0221] Item 18: In any of the preceding items, the diameter of the purge orifice (32) is defined as D1, wherein D1 / D2 is between 0.04 and 0.50.

[0222] Item 19: A burner according to any one of the preceding items, wherein the outer diameter of the ignition source (10) is defined as D2 and the inner diameter of the primary fuel conduit (20) is defined as D3, wherein D3 / D2 is 1.5 to 4.5, particularly 2.0 to 3.0.

[0223] Item 20: A burner according to any one of the preceding items, wherein the outer diameter of the ignition source (10) is defined as D2 and the inner diameter of the main oxidant conduit (30) is defined as D4, wherein D4 / D2 is 3.0 to 9.0, particularly 3.5 to 5.5.

[0224] Item 21: The burner according to any one of the preceding items, wherein the outer diameter of the ignition source (10) is defined as D2 and the inner diameter of the secondary fuel conduit (40) is defined as D5, wherein D5 / D2 is 5.0 to 11.0, particularly 5.5 to 7.0.

[0225] Item 22: The burner according to any one of the preceding items, wherein the diameter of the air premixing orifice (27) is defined as P0, wherein P0 / D2 is between 0.02 and 0.2.

[0226] Item 23: The burner according to any one of the preceding items, wherein the inner diameter of the discharge port (28) is defined as P1, wherein P1 / D2 is between 0.05 and 0.4.

[0227] Item 24: In any of the preceding items, the distance between the primary fuel conduit end plane (24) and the intermediate annular conduit end plane (36) is defined as L1, and the distance between the primary fuel conduit wall (29) and the intermediate annular conduit wall (37) is defined as L4, wherein L1 / L4 is 0.5 to 2.5, particularly 1.0 to 2.0.

[0228] Item 25: In any of the preceding items, the distance between the end plane (24) of the primary fuel conduit and the end plane (36) of the intermediate annular conduit is defined as L1, the distance between the end plane (36) of the intermediate annular conduit and the end plane (38) of the main oxidant conduit is defined as L2, and the inner diameter of the primary fuel conduit (20) is defined as D3, wherein (L1+L2) / D3 is 0.25 to 1.0, particularly 0.4 to 0.6.

[0229] Item 26: In any of the preceding items, the distance between the end plane (38) of the main oxidizer conduit and the end plane (46) of the secondary fuel conduit is defined as L3, and the inner diameter of the main oxidizer conduit (30) is defined as D4, wherein L3 / D4 is 0.05 to 0.25, particularly 0.1 to 0.2.

[0230] Item 27: In any of the preceding items, the distance between the primary fuel outlet (22) and the end plane (24) of the primary fuel conduit and / or the end plane (26) of the ignition chamber is defined as L0, and the inner diameter of the primary fuel conduit (20) is defined as D3, wherein L0 / D3 is 0.25 to 1.0, particularly 0.4 to 0.6.

[0231] Item 28: A burner according to any one of the preceding items, wherein the distance between the two rows of discharge holes (28) measured between the centers of the two rows of discharge holes (28) is defined as H, and the inner diameter of the discharge holes (28) is defined as P1, wherein H / P1 is 1.25 to 2.5.

[0232] Item 29: A burner according to any one of the preceding items, wherein the angle defined by the main axis (2) of the burner and the center of two adjacent exhaust holes (28) is defined as angle α, wherein angle α is 3 to 30 degrees.

[0233] Item 30: A burner according to any one of the preceding items, wherein the angle defined by the center of the main axis (2) of the burner and the center of two adjacent purge holes (32) is defined as angle β, wherein angle β is 5 to 40 degrees.

[0234] Item 31: A burner according to any one of the preceding items, wherein the angle defined by the center of the main axis (2) of the burner and the centers of two adjacent primary fuel outlet holes (23) is defined as angle θ, wherein angle θ is 10 to 40 degrees.

[0235] Item 32: A burner according to any one of items 16 to 31 above, wherein: i) D3 / D2 is 1.5 to 4.5, especially 2.0 to 3.0; and / or ii) D4 / D2 is 3.0 to 9.0, especially 3.5 to 5.5; and / or iii) D5 / D2 is 5.0 to 11.0, especially 5.5 to 7.0.

[0236] Item 33: A burner according to any one of items 16 to 32 above, wherein: i) L1 / L4 is 0.5 to 2.5, especially 1.0 to 2.0; and / or ii) L0 / D3 is 0.25 to 1.0, especially 0.4 to 0.6; and / or iii) (L1+L2) / D3 is 0.25 to 1.0, especially 0.4 to 0.6; and / or iv) L3 / D4 is 0.05 to 0.25, particularly 0.1 to 0.2; and / or v) H / P1 is 1.25 to 2.5; and or vi) D5 / D4 is 1.05 to 1.40, especially 1.1 to 1.25.

[0237] Item 34: A burner according to any one of items 16 to 33 above, wherein: i) Angle α is between 3 and 30 degrees; and / or ii) Angle β is between 5 and 40 degrees; and / or iii) Angle θ is 10 to 40 degrees.

[0238] Item 35: A burner according to any one of the preceding items, wherein the burner (1) is configured such that at the outlet of a given duct, i) The velocity of the primary fuel is between 30 feet per second and 500 feet per second, particularly between 40 feet per second and 400 feet per second; and / or ii) The velocity of the primary oxidant is between 5 feet / second and 300 feet / second, particularly between 10 feet / second and 200 feet / second; and / or iii) The speed of the secondary fuel is between 20 feet per second and 200 feet per second, particularly between 40 feet per second and 120 feet per second.

[0239] Item 36: A burner according to any one of the preceding items, wherein the velocity of the primary fuel is between 30 feet per second and 500 feet per second, particularly between 40 feet per second and 400 feet per second.

[0240] Item 37: A burner according to any one of the preceding items, wherein the velocity of the primary oxidant is between 5 feet per second and 300 feet per second, particularly between 10 feet per second and 200 feet per second.

[0241] Item 38: A burner according to any one of the preceding items, wherein the velocity of the secondary fuel is between 20 feet per second and 200 feet per second, particularly between 40 feet per second and 120 feet per second.

[0242] Item 39: A burner according to any one of the preceding items, wherein the swirl angle is 5 to 60 degrees.

[0243] Item 40: A burner according to any one of the preceding items, wherein the swirl angle is 30 to 45 degrees.

[0244] Item 41: A burner (1) according to any one of the preceding items, wherein the central ignition source (10) forms the “pipeline 1” of the burner.

[0245] Item 42: A burner (1) according to any one of the preceding items, wherein the primary fuel conduit (20) forms the “pipeline 2” of the burner.

[0246] Item 43: A burner (1) according to any one of the preceding items, wherein the main oxidant conduit (30) forms a “pipeline 3” of the burner, wherein the pipeline 3 is in particular an air conduit.

[0247] Item 44: The burner (1) according to any one of the preceding items, wherein the secondary fuel conduit (40) forms the “pipe 4” of the burner.

[0248] Item 45: A burner (1) according to any one of the preceding items, wherein all said conduits share a common central axis.

[0249] Item 46: A burner (1) according to any one of the preceding items, wherein all the said conduits are arranged concentrically about a common longitudinal axis at least in the downstream portion (5).

[0250] Item 47: A burner (1) according to any one of the preceding items, wherein all said conduits are substantially straight.

[0251] Item 48: A burner (1) according to any one of the preceding items, wherein the burner (1) comprises a configuration substantially as depicted in any of the figures in the accompanying drawings or any combination thereof.

[0252] Item 49: A burner according to any one of the preceding items, wherein the ignition chamber (25) is characterized by at least two (preferably two or three) steps on its wall, wherein each step includes a row of discharge holes (28).

[0253] Item 50: A burner according to any one of the preceding items, wherein the ignition chamber (25) extends from the primary fuel conduit outlet plane (55) to the intermediate annular conduit outlet plane (56).

[0254] Item 51: A burner according to any one of the preceding items, wherein the ignition chamber (25) includes a section having an outer diameter less than or equal to the inner diameter of the primary fuel conduit (20).

[0255] Item 52: A burner according to any one of the preceding items, wherein the ignition chamber (25) includes a section having an inner diameter greater than the outer diameter of the primary fuel conduit (20), but an outer diameter smaller than the inner diameter of the intermediate annular conduit (35).

[0256] Item 53: A method for operating a burner (1) according to any one of items 1 to 52, the method comprising the following steps i) Start the burner. ii) Optionally, the combustion rate of the burner is ramped up. iii) Start the secondary fuel, iv) Change the ratio of total heat supplied by the primary fuel and the secondary fuel as needed for the process.

[0257] Item 54: A method for operating a burner (1) according to any one of items 1 to 52, the method comprising the following steps i) Start the burner. ii) Optionally, the combustion rate of the burner is ramped up. iii) Start the secondary fuel, iv) Further adjust the flow rates of primary and secondary fuels and the equivalence ratio of the burner according to process requirements.

[0258] Item 55: The method according to Item 53 or 54, wherein step i) includes starting the primary oxidant, the igniter and the primary fuel.

[0259] Item 56: A burner according to any one of items 53 to 55 above, wherein the burner (1) is configured such that... i) During startup, approximately 100% of the total thermal power of the burner is provided by the primary fuel; and / or ii) During normal operation, approximately 5% to 70%, preferably 45% to 65%, of the total thermal power of the burner is provided by the primary fuel, and the corresponding remainder is provided by the secondary fuel.

[0260] Item 57: A burner according to any one of items 53 to 56 above, wherein the burner (1) is configured such that approximately 100% of the total thermal power of the burner is provided by the primary fuel during startup.

[0261] Item 58: A burner according to any one of items 53 to 57 above, wherein the burner (1) is configured such that during normal operation, about 5% to 70%, preferably 45% to 65% of the total thermal power of the burner is provided by the primary fuel.

[0262] Item 59: A burner according to any one of items 57 to 58, wherein the corresponding remainder is supplied by the secondary fuel.

[0263] Item 60: A burner according to any one of items 53 to 59 above, wherein the burner (1) is configured such that... i) The volumetric flow rate of the oxidant in the ignition chamber is approximately 5% to 25% of the total main oxidant flow rate; and / or ii) The volumetric flow rate of the premixed oxidant is approximately 2% to 10% of the total main oxidant flow rate.

[0264] Item 61: A burner according to any one of items 53 to 60 above, wherein the burner (1) is configured such that the volumetric flow rate of the oxidant in the ignition chamber is about 5% to 25% of the total main oxidant flow rate.

[0265] Item 62: A burner according to any one of items 53 to 61 above, wherein the burner (1) is configured such that the volumetric flow rate of the premixed oxidant is about 2% to 10% of the total main oxidant flow rate.

[0266] Item 63: A burner according to any one of items 63 to 62 above, wherein the burner (1) is configured such that during normal operation, the burner can be adjusted from 100% of the design combustion rate to a control ratio of about 1:30 according to the operating requirements. Example

[0267] The following examples are provided to further illustrate various aspects of the invention, but are by no means intended to limit it in any way.

[0268] Example 1 Design and manufacture exemplary test burners using air as an oxidant and natural gas as a primary fuel (tuning fuel) and a mixture of (H2, CO2, CH4) as a low BTU value exhaust fuel, and test them in a laboratory test furnace.

[0269] The burner operates under a wide range of conditions: full load during startup and heating, 100% design combustion rate with two fuels, and 50% low load with two fuels. Under these conditions, the average furnace wall temperature ranges from 450°F (during startup and single-fuel operation) to 1600°F (during dual-fuel operation).

[0270] Figure 8 The curves showing flame length versus burner combustion rate indicate that, over a wide range of operating conditions, flame length (L) / D3 is approximately 20.0 or less. Furthermore, this result is unexpected considering the low swirl number associated with the flow field exiting the burner nozzle. The swirl number S is defined as the axial flux of angular momentum G. Φ With linear momentum G x The ratio of the product of the outer radius R4 of the swirl blade (equal to 0.5 times D4). That is: Calculations of the swirl number at the outlet flow field of the composite nozzle show that, for Figure 8 The operating conditions indicated are swirl numbers between approximately 0.2 and 0.3. Swirl numbers within this range are classified as weak swirling and generally have no substantial effect on flame shortening compared to the non-swirling case. (See prior art from Hawthorne, WR, DS Weddell, and HC Hottel. "Mixing and combustion in turbulent gasjets," Symposium on Combustion, Flame, and Explosion Phenomena). Symposium on Combustion and Flame, and Explosion Phenomena (Figure 6, Volume 3, Issue 1, Elsevier, 1948) The non-swirling burner flame typically exhibits a higher characteristic than that from... Figure 8The dimensionless flame length is an order of magnitude larger than that of the previous burner. The fact that this burner can produce a short flame under a wide range of operating conditions with weak swirl is due to several unique features of this burner. First, the feature of injecting primary fuel through multiple orifices of the jet diameter (D0) helps the fuel entrain surrounding air in the fuel jet, allowing the fuel jet momentum transfer and combustion rates to be closer to the burner occurrence compared to prior art non-premixed burners. Furthermore, these same multiple orifices (D0) contribute to the generation of a momentum distribution across the exit plane of the ignition cup (i.e., at diameter D3), which consists of alternating peaks and valleys of high and low momentum. Without being bound by theory, it is assumed that this non-uniform momentum distribution makes the ignited primary fuel / ignition air mixture more susceptible to the axial momentum disturbance effect of the primary air swirl. Therefore, even at relatively low swirl numbers, the swirl, combined with the multiple orifices (D0), further reduces the flame length. Second, the turbulence generator in the exhaust duct helps increase the turbulence intensity of the secondary fuel flow, which enables an increased mixing rate of the secondary fuel with air, and thus, completes the combustion of the secondary fuel over a short downstream distance. Third, the exhaust port (28) provides an oxidizer in the ignition cup, which allows the fuel to entrain air in the fuel jet before reaching the burner outlet plane. These unique design aspects of the burner, along with the specific velocity range of the fluid flow, contribute to enhanced oxidizer-fuel mixing, thereby achieving complete combustion over a short distance, although the swirl number is below 0.3. Without the aforementioned burner design features, this design would require a very high swirl angle, resulting in increased back pressure requirements and potentially damaging the burner and / or causing rapid heat release and hot spots, and still would not achieve the wide range of operational flexibility required by the burner as discussed below.

[0271] Furthermore, the burner is capable of producing a stable flame at a high turnout ratio of 1:30 and an equivalence ratio of 0.25. This performance is due to the unique configuration of the burner hardware, including the position of the air purge plate (73), its stepped design, and the ability to allow axial airflow over the air purge plate (73), which provides a robust flame anchoring position. Figure 9 As illustrated, the burner provides multiple flame anchoring positions based on the burner's total combustion rate. At high combustion rates, close to the burner's design combustion rate, the flame is anchored in two positions: one near the air purge plate (73) and the second on the circumferential inner wall of the cyclone outlet plane. At low combustion rates, under low load conditions and low equivalence ratios, the flame continues to be anchored at the position of the air purge plate (73) without any extinguishing, due to the recirculation zone setting in the area created by the stepped design of the air purge plate (73). Furthermore, the air purge plate (73) is recessed L1 from the cyclone outlet plane (34), which allows the flame anchoring to be relatively unaffected by the furnace atmosphere.

[0272] The burner is capable of producing a stable flame for a wide range of primary and secondary fuel splits. The primary fuel can supply 5% to 100% of the total burner heat output, with the remaining margin coming from the secondary fuel. The primary reason for this flexibility is the strong flame anchoring zone of the primary fuel provided by the air purge plate (73), as discussed above, which allows the primary fuel heat input to be reduced to as low as 5% of the total heat output.

[0273] The burner's design features allow the combustion-supporting agent to be purged radially and axially within the ignition cup, maintaining the circumferential wall's coolness by preventing direct contact between the circumferential wall and the flame. The burner operated in a factory-installed reactor and, after one year of operation, was found to be free of blemishes, with no damage to the burner hardware, particularly the ignition cup.

[0274] Furthermore, the burner offers improved performance in terms of NOx emissions. The exhaust orifice (28) supplies air into the ignition cup, which can be entrained by the fuel jet before the fuel leaves the burner's outlet plane. This enhanced mixing, achieved through a unique burner cup nozzle (ignition chamber) design, thus allows for a lower peak temperature compared to the typical characteristics of non-premixed burners. This lower peak temperature of the burner flame mimics the peak temperature of partially premixed air-fuel combustion, rather than the peak temperature of non-premixed combustion.

[0275] Finally, the burner ignites well even under cold furnace conditions at equivalence ratios as low as 0.25. This is possible due to the unique design of the ignition cup, which provides a region where localized ignition can be initiated and maintained while the composite fuel-air mixture remains below the overall burner flammability limit of natural gas, which occurs at an equivalence ratio of approximately 0.48. Specifically, this is because a portion of the primary air is introduced into the ignition chamber via the circumferential wall of the chamber, which is perpendicular to the fuel distribution nozzle. This is used to vigorously mix the fuel and the “ignition” air, creating numerous “pockets” of localized fuel-air mixtures with equivalence ratios within the combustible zone, thus enabling reliable and repeatable ignition even when the composite gas mixture has a non-flammable fuel concentration.

Claims

1. A burner (1), comprising: A primary fuel conduit (20) includes a primary fuel outlet (22) having a plurality of primary fuel outlet holes (23) for supplying primary fuel to an ignition chamber (25), wherein the wall surrounding the ignition chamber (25) includes a plurality of discharge holes (28). A main oxidizer conduit (30) for supplying the main oxidizer, the main oxidizer conduit including an intermediate annular conduit (35) in the downstream portion (5) of the burner, the intermediate annular conduit (35) being configured to allow diversion of the main oxidizer such that a first portion is introduced into the ignition chamber (25) via the plurality of discharge holes (28) to mix with the primary fuel, and a second portion is introduced into the cyclone section (33); A secondary fuel conduit (40) for supplying secondary fuel, the secondary fuel conduit having a secondary fuel outlet (44) at its downstream end. In at least the downstream portion (5) of the burner (1) in which a primary fuel outlet (22), an ignition chamber (25), an intermediate annular conduit (35) and a secondary fuel outlet (44) are present, the primary fuel conduit (20) is surrounded by the main oxidant conduit (30) and the secondary fuel conduit (40).

2. The burner according to claim 1, wherein i) The ignition chamber (25) is positioned within the primary fuel conduit (20) and extends from the primary fuel outlet (22) to the end plane (24) of the primary fuel conduit, wherein the primary fuel conduit wall (29) surrounds the ignition chamber (25) and includes a plurality of discharge holes (28), and ii) The burner further includes an ignition source (10) terminating in the ignition chamber (25), wherein the main axis (2) of the burner (1) preferably coincides with the central axis (15) of the ignition source (10), and iii) The burner (1) further includes a turbulence generator (47) in the secondary fuel conduit (40).

3. The burner according to claim 1, wherein the ignition chamber (25) is located within the primary fuel conduit (20) and extends from the primary fuel outlet (22) to the end plane (24) of the primary fuel conduit, wherein the primary fuel conduit wall (29) surrounds the ignition chamber (25) and includes a plurality of discharge holes (28).

4. The burner according to claim 1, wherein the ignition chamber (25) extends from the primary fuel outlet (22) to the intermediate annular conduit outlet plane (56), wherein the wall surrounding the ignition chamber (25) includes at least two (preferably two or three) steps with increasing radially extending annular conduits, each step including a plurality of discharge holes (28).

5. The burner according to claim 1, wherein the ignition chamber (25) extends from the primary fuel outlet (22) to the intermediate annular duct outlet plane (56), wherein the wall surrounding the ignition chamber (25) comprises two sections, wherein: i) A first section extends from the primary fuel outlet (22) to the end plane (24) of the primary fuel conduit, wherein the wall (29) of the primary fuel conduit surrounding the section includes a plurality of discharge holes (28), and ii) The second section has an inner diameter larger than the outer diameter of the primary fuel conduit (20), but the second section has an outer diameter smaller than the inner diameter of the intermediate annular conduit (35), and includes a plurality of additional discharge ports (28), wherein iii) The burner optionally further includes an air purge plate (73) having purge holes (32), the air purge plate extending between the outer diameter of the first section and the inner diameter of the second section, and iv) The burner optionally further includes two mechanical mixer plates (74), each mechanical mixer plate being positioned downstream of and adjacent to the two sections, and v) The burner optionally further includes a purge plate (73) having a purge hole (32) between the outer diameter of the second section and the inner diameter of the intermediate annular conduit (35).

6. The burner according to claim 1, wherein the ignition chamber (25) extends from the primary fuel outlet (22) to the intermediate annular duct outlet plane (56), wherein the wall surrounding the ignition chamber (25) comprises two sections, wherein i) The first section has an outer diameter smaller than the inner diameter of the primary fuel conduit (20) and includes a plurality of discharge holes (28), wherein the primary fuel conduit wall (29) surrounding the first section includes a plurality of discharge holes (28), and wherein the first section further includes means for allowing the primary oxidant to additionally enter the ignition chamber (25) in the flow direction between two rings of primary fuel outlet holes. ii) The second section has an inner diameter larger than the outer diameter of the primary fuel conduit (20), but the second section has an outer diameter smaller than the inner diameter of the intermediate annular conduit (35), and includes a plurality of additional discharge ports (28), wherein iii) The burner optionally further includes a purge plate (73) having a purge hole (32) between the outer diameter of the first section and the inner diameter of the second section, and iv) The burner optionally further includes a purge plate (73) having a purge hole (32) between the outer diameter of the second section and the inner diameter of the intermediate annular conduit (35).

7. The burner according to any one of the preceding claims, wherein the burner further comprises an ignition source (10) terminating in the ignition chamber (25), Specifically, the ignition source (10) is a central ignition source having a central axis (15) and a conduit end plane (16). In particular, the main axis (2) of the burner (1) coincides with the central axis (15) of the ignition source (10). In particular, in at least the downstream portion (5) of the burner (1), the central ignition source (10) is surrounded by the primary fuel conduit (20), the main oxidizer conduit (30) and the secondary fuel conduit (40).

8. The burner according to any one of the preceding claims, wherein: i) The end plane (24) of the primary fuel conduit corresponds to the end plane (26) of the ignition chamber; and / or ii) The primary fuel conduit further includes an air premixing orifice (27) upstream of the primary fuel outlet (22); and / or iii) The main oxidant conduit (30) further includes at least one air purge plate (73), the at least one air purge plate including purge holes (32) in the flow direction parallel to the main axis (2) of the burner.

9. The burner according to any one of the preceding claims, wherein the main oxidant conduit (30) further comprises a swirler section (33), and in particular, wherein the intermediate annular conduit (35) is configured to allow the main oxidant to be diverted into two portions, wherein the second portion is introduced into the swirler section (33); In particular, the swirl angle is 5 to 60 degrees, preferably 30 to 45 degrees.

10. The burner according to any one of the preceding claims, wherein the burner (1) further comprises a turbulence generator (47) in the secondary fuel conduit (40).

11. The burner according to any one of the preceding claims, wherein: i) The diameter of the primary fuel outlet orifice (23) is defined as D0, where D0 / D2 is between 0.04 and 0.5; and / or ii) The diameter of the purge hole (32) is defined as D1, where D1 / D2 is between 0.04 and 0.

5.

12. The burner according to any one of the preceding claims, wherein: i) The outer diameter of the ignition source (10) is defined as D2, and the inner diameter of the primary fuel conduit (20) is defined as D3, wherein D3 / D2 is 1.5 to 4.5, particularly 2.0 to 3.0; and / or ii) The outer diameter of the ignition source (10) is defined as D2, and the inner diameter of the main oxidant conduit (30) is defined as D4, wherein D4 / D2 is 3.0 to 9.0, particularly 3.5 to 5.5; and / or iii) The outer diameter of the ignition source (10) is defined as D2, and the inner diameter of the secondary fuel conduit (40) is defined as D5, wherein D5 / D2 is 5.0 to 11.0, particularly 5.5 to 7.

0.

13. The burner according to any one of the preceding claims, wherein: i) The diameter of the air premixing orifice (27) is defined as P0, where P0 / D2 is between 0.05 and 0.2; and / or ii) The inner diameter of the discharge port (28) is defined as P1 / D2, where P1 / D2 is between 0.05 and 0.4; and / or iii) The distance between the end plane (24) of the primary fuel conduit and the end plane (36) of the intermediate annular conduit is defined as L1, and the distance between the wall of the primary fuel conduit (29) and the wall of the intermediate annular conduit (37) is defined as L4, wherein L1 / L4 is 0.5 to 2.5, particularly 1.0 to 2.0; and / or iv) The distance between the end plane (24) of the primary fuel conduit and the end plane (36) of the intermediate annular conduit is defined as L1, the distance between the end plane (36) of the intermediate annular conduit and the end plane (38) of the main oxidant conduit is defined as L2, and the inner diameter of the primary fuel conduit (20) is defined as D3, wherein (L1+L2) / D3 is 0.25 to 1.0, particularly 0.4 to 0.6; and / or v) The distance between the end plane (38) of the main oxidizer conduit and the end plane (46) of the secondary fuel conduit is defined as L3, and the inner diameter of the main oxidizer conduit (30) is defined as D4, wherein L3 / D4 is 0.05 to 0.25, particularly 0.1 to 0.2; and / or vi) The distance between the primary fuel outlet (22) and the end plane (24) of the primary fuel conduit and / or the end plane (26) of the ignition chamber is defined as L0, and the inner diameter of the primary fuel conduit (20) is defined as D3, wherein L0 / D3 is 0.25 to 1.0, particularly 0.4 to 0.6; and / or vii) The distance between the two rows of discharge holes (28), measured between their centers, is defined as H, and the inner diameter of the discharge holes (28) is defined as P1, where H / P1 is 1.25 to 2.5; and / or viii) The ratio of the area of ​​all discharge holes in a row to the surface area of ​​the cylinder with height P1 and inner diameter D2 is between 10% and 55%; and / or ix) The air purge plate (73) has a porosity in the range of 2% to 15% (defined by dividing the total open area on the plate that allows airflow by the cross-sectional area of ​​the plate); and / or x) The primary fuel outlet plate (72) has a porosity in the range of 2% to 25% (defined by dividing the total open area on the plate that allows fuel flow by the cross-sectional area of ​​the plate).

14. The burner according to any one of the preceding claims, wherein the burner (1) is configured such that... i) The velocity of the primary fuel is between 30 feet per second and 500 feet per second, particularly between 40 feet per second and 400 feet per second; and / or ii) The velocity of the primary oxidant is between 5 feet / second and 300 feet / second, particularly between 10 feet / second and 200 feet / second; and / or iii) The speed of the secondary fuel is between 20 feet per second and 200 feet per second, particularly between 40 feet per second and 120 feet per second.

15. The burner according to any one of the preceding claims, wherein the secondary fuel conduit (40) is adjacent to the main oxidizer conduit (30). Preferably, the inner diameter of the secondary fuel conduit (40) is defined as D5; the inner diameter of the main oxidant conduit (30) is defined as D4; and D5 / D4 is between 1.05 and 1.40, more preferably between 1.1 and 1.

25.

16. A method for operating a burner (1) according to any one of claims 1 to 11, the method comprising the steps of: i) Start the burner. ii) Increase the combustion rate of the burner at an angle. iii) Start the secondary fuel, iv) Further adjust the flow rates of primary and secondary fuels and the equivalence ratio of the burner according to process requirements.

17. The method of claim 16, wherein step i) comprises activating the primary oxidant, the ignition source, and the primary fuel.

18. The method according to any one of claims 16 to 17, wherein the burner (1) operates such that... i) During startup, approximately 100% of the total thermal power of the burner is provided by the primary fuel; and / or ii) During normal operation, approximately 5% to 70%, preferably 45% to 65%, of the total thermal power of the burner is provided by the primary fuel, and the corresponding remainder is provided by the secondary fuel.

19. The method according to any one of claims 16 to 18, wherein the burner (1) operates such that... i) The volumetric flow rate of the oxidant in the ignition chamber is approximately 5% to 25% of the total main oxidant flow rate; and / or ii) The volumetric flow rate of the premixed oxidant is approximately 2% to -10% of the total main oxidant flow rate.

20. The method according to any one of claims 16 to 19, wherein the burner (1) is operated such that during normal operation, the burner can be adjusted from a design combustion rate of 100% to a control ratio of approximately 1:30 according to operational requirements.

Images