A burner assembly and a combustion device

Abstract

The present invention relates to the technical field of power equipment, and discloses a burner assembly and a combustion device, wherein the burner assembly comprises: a first swirler and a first fuel pipe, wherein the first swirler has a first air channel, and the first fuel pipe is located in the first air channel; the surface of the first fuel pipe is provided with turbulent patterns and a plurality of first fuel holes, and the first fuel pipe sprays fuel into the first air channel through the first fuel holes. In the above-mentioned burner assembly, when air enters the first swirler through the first air channel, it will pass through the first fuel pipe. Since the surface of the first fuel pipe is provided with turbulent patterns, the air acts on the turbulent patterns when passing around the first fuel pipe, generating obvious turbulence, fully increasing the turbulence of the air, and quickly mixing with the fuel sprayed from the first fuel hole, thereby increasing the mixing uniformity of the fuel and the air, facilitating full combustion, and significantly reducing NOx emissions.

Description

Technical Field

[0001] The present invention relates to the technical field of power equipment, and particularly relates to a burner assembly and a combustion device. Background Art

[0002] Combustion pollution emissions have caused increasingly serious harm to human health and the environment and have received a great deal of attention. Moreover, laws, regulations, and relevant policies regarding the control of pollution emissions have become increasingly strict. Certain requirements have also been put forward for the NOx pollution emissions problem of micro gas turbines. At present, the technical research on low NOx emissions by each gas turbine manufacturer has become mature, and the NOx emissions of common mainstream products can generally reach 15 ppm or even below 10 ppm. To achieve low combustion emissions, it is necessary to finely design and transform the combustion equipment to reduce the NOx emissions to the extreme while ensuring combustion stability.

[0003] The combustion products of a micro gas turbine under high-temperature flames contain NOx (nitrogen oxides), and NOx mainly includes NO and NO2. Technical measures should be taken as much as possible to reduce the NOx emissions of the micro gas turbine. In a gas turbine, NOx is mainly thermal NOx generated by high combustion temperatures. To reduce the NOx emissions of the gas turbine, the key lies in controlling the temperature in the combustion chamber at a relatively low level (generally 1700K - 1900K; if the temperature is lower, it will affect the combustion efficiency), and at the same time making the temperature distribution in the combustion chamber uniform. This requires that the fuel distribution in the combustion area is very uniform, and local high-concentration points of high-concentration fuel should be minimized as much as possible. Currently, the main low NOx emission burners for ground gas turbines include fuel staging, lean premixing, steam humidification, etc. Ground gas turbines commonly use dry low-emission technologies. By fuel staging and making the gas distribute as evenly as possible in the premixing section of the burner, the mixture of gas and air can form a temperature generally lower than 2000K in the combustion area after being ejected from the burner, reducing the emissions of thermal nitrogen oxides.

[0004] Existing medium-sized, small-sized, and heavy-duty gas combustion chambers often adopt the configuration of a main combustion burner with a radial swirler structure and an axial swirler diffusion pilot burner. A small part of the fuel undergoes diffusion combustion through the pilot burner to achieve stable combustion, and most of the fuel undergoes premixing through the main combustion burner. If it is necessary to further reduce the NOx emissions, it is necessary to optimize the structure and transform the two-stage swirler.

[0005] Therefore, how to further reduce the NOx emissions is an urgent problem to be solved. Summary of the Invention

[0006] The present invention discloses a burner assembly and a combustion device for further reducing the NOx emissions.

[0007] In a first aspect, a burner assembly is provided, which includes: a first swirler and a first fuel pipe, the first swirler having a first air channel, the first fuel pipe being located in the first air channel; a surface of the first fuel pipe is provided with turbulent patterns and a plurality of first fuel holes, and the first fuel pipe sprays fuel into the first air channel through the first fuel holes.

[0008] In the above-mentioned burner assembly, when the air enters the first swirler through the first air channel, it will pass through the first fuel pipe. Since the surface of the first fuel pipe is provided with turbulent patterns, the air acts on the turbulent patterns when passing around the first fuel pipe, generating obvious turbulence, fully increasing the turbulence of the air, and quickly mixing with the fuel injected from the first fuel hole, thereby increasing the mixing uniformity of the fuel and air, facilitating full combustion, and significantly reducing NOx emissions.

[0009] Optionally, the first fuel pipe passes through two opposite side walls of the first air channel, and threads are distributed on the circumferential surface of the first fuel pipe; the portion of the threads of the first fuel pipe located between the two side walls forms the turbulent pattern; at least one end of the first fuel pipe is connected to a limiting fixing member through the threads.

[0010] Optionally, it also includes a second swirler, which has a second air channel; the first air channel surrounds the second air channel, the air inlet of the second air channel faces away from the second air channel, the air outlet of the second air channel surrounds the air outlet of the first air channel, and the first fuel pipe extends axially.

[0011] Optionally, it also includes an annular fuel chamber surrounding the second air channel and fixed to the outer wall of the second air channel, and a fuel supply pipe connected to the annular fuel chamber; one end of the first fuel pipe is fixedly connected to the annular fuel chamber, and the other end is connected to the limiting fixing member through the thread to clamp and fix the two opposite side walls of the second air channel.

[0012] Optionally, there are multiple first fuel pipes, and the multiple first fuel pipes are distributed around the second air channel at intervals.

[0013] Optionally, there are multiple first swirlers, and the multiple first swirlers are stacked in the axial direction, and each of the first fuel pipes passes through multiple first air channels in sequence.

[0014] Optionally, every two adjacent first air channels share one side wall.

[0015] Optionally, it further includes a second fuel pipe and a head igniter. The second fuel pipe is located in the second air passage, and a plurality of second fuel holes are distributed on the circumferential surface of the second fuel pipe. A blade assembly is provided in the second air passage, the second fuel holes are located upstream of the blade assembly, and the ignition end of the head igniter is located at the second fuel holes.

[0016] Optionally, a counterbore is formed at the surface opening of the first fuel hole on the first fuel pipe, and the inner diameter of the counterbore is larger than the inner diameter of the first fuel hole.

[0017] In a second aspect, a combustion device is provided. The combustion device includes a casing assembly, a flame tube assembly, and the burner assembly according to any one of the above technical solutions. The flame tube assembly is located in the casing assembly, and the opening of the flame tube assembly is butted against the air outlet of the first air passage.

[0018] Compared with the prior art, the combustion device and the burner assembly have the same advantages, which will not be elaborated here. Description of the Drawings

[0019] Figure 1 It is a cross-sectional view of the combustion device provided by the embodiment of the present application;

[0020] Figure 2 It is Figure 1 the cross-sectional view of the burner assembly in

[0021] Figure 3 It is Figure 2 the cross-sectional view of the first swirler perpendicular to its axis in

[0022] Figure 4 It is Figure 1 the three-dimensional view of the burner assembly in

[0023] Figure 5 It is Figure 4 a sectional view of a deformation of the burner assembly shown in

[0024] Figure 6 It is Figure 5 the three-dimensional view of the burner assembly shown in Detailed Embodiments

[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] In conjunction with Figures 1 to 6:

[0027] The burner assembly 1 provided in the embodiment of the present application includes: a first swirler 18 and a first fuel pipe 13. The first swirler 18 has a first air passage T1. The first fuel pipe 13 is located in the first air passage T1. The surface of the first fuel pipe 13 is provided with turbulent lines and a plurality of first fuel holes 131. The first fuel pipe 13 sprays fuel into the first air passage T1 through the first fuel holes 131. The first swirler 18 and the first fuel pipe 13 serve as core components of the first burner.

[0028] In the above-mentioned burner assembly 1, when the air enters the first swirler 18 through the first air channel T1, it will pass through the first fuel pipe 13. Since the surface of the first fuel pipe 13 is provided with turbulent patterns, the air acts on the turbulent patterns when passing around the first fuel pipe 13, generating obvious turbulence, fully increasing the turbulence of the air, and quickly mixing with the fuel injected from the first fuel hole 131, thereby increasing the mixing uniformity of the fuel and air, facilitating full combustion, and significantly reducing NOx emissions.

[0029] In a specific embodiment, the first fuel pipe 13 passes through two opposite side walls of the first air channel T1, which can be the inner wall 183 and the outer wall 181, and the circumferential surface of the first fuel pipe 13 is distributed with threads 132; the thread 132 of the first fuel pipe 13 is located between the two side walls (such as the inner wall 183 and the outer wall 181) to form the above-mentioned spoiler pattern; at least one end of the first fuel pipe 13 is connected to the limited fixing member 15 through the thread 132, and the limited fixing member 15 can be configured only at one end of the first fuel pipe 13, or can also be configured at both ends. The limited fixing member 15 can be a nut, and the limited fixing member 15 is used to limit the inner wall 183 or the outer wall 181 of the side wall. The standard thread can be processed on the circumferential surface of the first fuel pipe 13 as the thread 132, and the standard thread can not only serve as a threaded connection structure of the limited fixing member 15, but also form the above-mentioned spoiler pattern to increase the air turbulence. It is equivalent to using a standard thread formed at one time to play two roles at the same time.

[0030] In a specific embodiment, the burner assembly 1 further includes a second swirler 16. The second swirler 16 can be an axial swirler and serves as a duty second swirler 16 with a second air passage T2. The air outlet of the second air passage T2 can be along the axial direction L. Specifically, the second swirler 16 includes second swirler vanes 163, an inlet passage enclosure 162 located upstream, and an outlet section enclosure 161 located downstream. Among them, the inlet passage enclosure 162 and the outlet section enclosure 161 enclose the above-mentioned second air passage T2, and the second swirler assembly 163 is located in the second air passage T2, specifically, it can be located at the connection of the inlet passage enclosure 162 and the outlet section enclosure 161, and is used to form a swirl for the air or mixed gas passing through the second air passage T2. The air generates a swirl low-speed zone after passing through the second swirler assembly 163, so that the duty flame is firmly anchored at the air outlet of the second air passage T2. The first swirler 18 can be a radial swirler. The first air passage T1 surrounds the second air passage T2. The air outlet of the second air passage T2 surrounds the air outlet of the first air passage T1 and faces along the axial direction L. The inlet direction and the outlet direction of the inner wall 183 can be approximately at a 90-degree bend angle, and the bend position is in a fillet transition. The outer wall 181 can have a shape similar to that of the inner wall 183. The outer wall 181 and the inner wall 183 are arranged along the axial direction L, and a first air passage T1 with an annular distribution is formed between them. The inlet direction of the first air passage T1 is radially away from the second air passage T2. The air enters the first air passage T1 through the above-mentioned inlet, mixes with the fuel ejected from the first fuel pipe 13 in the first air passage T1, and after swirling through the first swirler assembly 183 in the first air passage T1, it is ejected from the first air passage T1 approximately along the axial direction L. It can be understood that the outer wall 181 can adopt a contracted streamline-shaped wall surface to increase the air flow velocity in the first air passage T1 and reduce the residence time to cope with the possible flame flashback caused by hydrogen-containing fuels, so that the burner assembly has the ability to burn fuels with a low proportion of hydrogen; the outer wall 181 can also adopt a diffused streamline-shaped wall surface. The first fuel pipe 13 extends along the axial direction L to facilitate passing through the inner wall 183 and the outer wall 181 distributed along the axial direction L. The outer wall 181, the first swirler assembly 182, and the inner wall 183 can be welded and fixed in sequence. The first swirler vanes in the first swirler assembly 183 and the second swirler vanes in the second swirler assembly 163 can both adopt airfoil vanes or curved vanes.

[0031] In a specific embodiment, the burner assembly 1 further includes an annular fuel chamber 19 surrounding the second air passage T2 and fixed to the outer wall of the second air passage T2 (such as the inlet passage surrounding wall 162), and a fuel supply pipe 12 connected to the annular fuel chamber 19, and the fuel is supplied to the annular fuel chamber 19 through the fuel supply pipe 12 extending in the axial direction L. The supply pipe 12 can be specifically connected to the rear wall surface 191 of the annular fuel chamber 19, and the fuel can be gas, and the gas fuel is dispersed in the annular fuel chamber 19; one end of the first fuel pipe 13 is fixedly connected and connected to the annular fuel chamber 19, and the other end is connected to the limit fixing member 15 through the thread 132 to clamp and fix the two opposite side walls of the second air passage T2. The annular fuel chamber 19 also plays a role in fixing the first fuel pipe 13 and supplying fuel to the first fuel pipe 13.

[0032] In a specific embodiment, the number of the first fuel pipes 13 is multiple (e.g., 12 to 24), and the multiple first fuel pipes 13 are spaced and distributed around the second air channel T2 to fix different positions of the inner wall 183 and the outer wall 181 in the circumferential direction, and supply fuel to the first air channel T1 at different angles in the circumferential direction. In addition, each first fuel pipe 13 is fixed and communicated with the annular fuel chamber 19, and the annular distribution of the annular fuel chamber 19 plays a role in fixing and supplying fuel to different first fuel pipes 13 in the annular direction.

[0033] The main fuel enters the annular fuel chamber 19 from the fuel supply pipe 12 of the main fuel, is distributed from the annular fuel chamber 19 to a plurality of first fuel pipes 13, and is ejected from the first fuel holes 131 to be premixed with the air.

[0034] In a specific embodiment, there are multiple first swirlers 18, and the multiple first swirlers 18 are stacked along the axial direction L. Each first fuel pipe 13 passes through multiple first air channels T1 in sequence, that is, the first fuel pipe 13 passes through the axially relatively arranged side walls of the multiple first swirlers 18 at the same time. The first fuel pipe 13 can fix multiple first swirlers 18 at the same time, and the structure is simple and stable. At the same time, the turbulent lines formed by the surface threads 132 can form turbulence in each first air channel T1. Figure 5 In the embodiment, two first swirlers 18 are arranged between the limit fixing member 15 and the annular fuel chamber 19, which increases the radial grading level and creates two-stage radial swirlers with different swirl intensities and fuel concentrations. Among them, the length of the first fuel pipe 13 also needs to be lengthened accordingly, and the number of openings of the first fuel hole 131 also increases accordingly. Different first swirlers 18 can use first swirling components 182 with different swirl numbers, and use different fuel concentration ratios, which can increase the adaptability, adjustability and fuel adaptability of the combustion chamber working conditions.

[0035] The burner with a two-stage radial cyclone can be applied to the low-emission combustion device of a gas turbine.

[0036] In a specific embodiment, every two adjacent first air channels T1 share a side wall. Specifically, Figure 5 in, the first cyclone 18 located on the outer side of the axial direction L includes an inner wall 185 and an outer wall 184. A first air channel T1 is formed between the inner wall 185 and the outer wall 184. A first swirl assembly 182 is arranged in the two first air channels T1. The first swirl assembly 182 includes a plurality of first swirl vanes for swirling air or mixed gas. The inner wall 185 of the outer first cyclone 18 and the outer wall 181 of the inner first cyclone 18 are formed by the same side wall. In this way, the structure of the first cyclone 18 can be simplified.

[0037] In a specific embodiment, the burner assembly 1 further includes a second fuel pipe 11 and a head igniter 17. The second fuel pipe 11 is located in the second air passage T2. A plurality of second fuel holes 111 are distributed on the circumferential surface (or cylindrical surface) of the second fuel pipe 11. A vane assembly (specifically, the second swirl assembly 163 can be referred to, and the second swirl assembly 163 includes a plurality of second swirl vanes) is provided in the second air passage T2. The second fuel holes 111 are located upstream of the above-mentioned vane assembly (the second swirl assembly 163 can be referred to), and the ignition end of the head igniter 17 is located at the second fuel holes 111. The second swirl assembly 163 swirls the air entering the second air passage T2, so that the swirling air is fully mixed with the fuel ejected from the second fuel holes 111 to form a mixed gas, which is convenient for forming a semi-premixed combustion mode and is beneficial to stabilizing the flame. Compared with the existing diffusion duty burner, while strengthening the combustion mixture, the NOx emission is significantly reduced. Specifically, 6 to 10 second fuel holes 111 can be uniformly arranged along the circumferential direction on the cylindrical surface of the second fuel pipe 11. For general gas turbines, due to their relatively small geometric size, the igniter is placed on the side wall of the combustion chamber liner, far from the fuel injection holes of the burner. There are problems such as insufficient ignition success rate and narrow ignition boundary during the start-up stage, and it is difficult to re-ignite due to the position of the igniter after accidental flameout. In the embodiment of the present application, the head igniter 17 can increase the ignition success rate and the ignition boundary width, instantly re-ignite the duty fuel ejected from the second fuel holes 111 in case of accidental flameout, and reduce the ignition failure rate to improve the safety of the unit. For example, the front end of the head igniter 17 is placed above the second fuel holes 111. The fuel gas is injected into the second air passage T2 through the duty fuel holes 111, and after passing over the head igniter 17, it is ignited to generate a stable duty flame. The duty fuel of the second fuel pipe 11 serves as a flame stabilizer and also plays a role in ignition, increasing the success rate of conventional ignition and hot start ignition. The second swirler 16 and the second fuel holes 111 are the core components of the second burner. The first burner and the second burner are two burners with independent air and fuel channels.

[0038] In a specific embodiment, a counterbore 133 is formed at the surface opening of the first fuel hole 131 in the first fuel pipe 13, and the inner diameter of the counterbore 133 is larger than that of the first fuel hole 131. Each first fuel pipe 13 is arranged with 2 to 4 first fuel holes 131 on each side along the axial direction L, with a total of 4 to 8 first fuel holes 131 on both sides. The first fuel hole 131 has a counterbore 133 on the surface near the thread 132. When the fuel is ejected through the first fuel hole 131, due to the increase in the aperture of the counterbore 133 relative to the first fuel hole 131, the fuel injection speed decreases, the jet depth is smaller, and when flowing out of the first fuel pipe 13, it is fully mixed with the air with high turbulence generated by the thread 132 on the surface of the first fuel pipe 13, rather than directly jetting onto the first swirl blades of the first swirl assembly 182. The installation angle α of the first swirl blades of the first swirl assembly 182 is between 40° and 70°, and the angle α can be adjusted according to the change of the fuel composition to control the residence time of the fuel-air mixture in the first air passage T1.

[0039] The embodiment of the present application provides a combustor with dual igniters based on the lean-premixed concept of dry low-emission combustion, which can burn conventional natural gas, hydrogen-containing gas, associated oilfield gas, medium and high calorific value synthesis gas, etc.

[0040] Based on the same inventive concept, the embodiment of the present application further provides a combustion device, which includes a casing assembly 2, a flame tube assembly 3, and the burner assembly 1 provided in the above embodiment. The flame tube assembly 3 is located inside the casing assembly 2. The flame tube assembly 3 serves as a container for the flame, and the opening at its head is docked with the air outlet of the first air passage T1. A sidewall igniter 21 is provided on the inner sidewall of the casing assembly 2, and the front end of the sidewall igniter 21 is flush with the inner wall surface of the flame tube assembly 31 for igniting the air-gas mixture in the flame tube assembly 31.

[0041] The gas-air mixture in the first air passage T1 enters the flame tube assembly 3 through the air outlet of the first air passage T1 for combustion. The front end of the flame tube assembly 3 is evenly provided with flame tube cooling air film holes 32 along the circumferential direction to reduce the heat load on the front wall surface of the flame tube. The front cone section 33 of the flame tube at the head of the flame tube assembly 3 can generate an external corner recirculation zone to stabilize the flame shape and continuously provide heat for the unburned mixture coming out of the burner to quickly ignite it.

[0042] The burner assembly 1, the combustor casing assembly 2, and the flame tube assembly 3 are connected by bolts. Among them, the front end of the flame tube assembly 2 is provided with a flame tube mounting hole plate 31, and the flame tube mounting hole plate 31 can serve as a function of installation and fixation, and is clamped between the burner head flange 14 of the burner assembly 1 and the casing flange 22. The head of the entire flame tube assembly 3 is fixed against the flame tube mounting hole plate 31.

[0043] The flame tube mounting orifice plate 31 is provided with a row of holes 34, which can adjust the air ratio while playing the role of installation, absorb energy through the dense row of holes 34 to reduce the air pressure fluctuation, and reduce the possibility of combustion oscillation. The air required by the burner assembly 1 enters the burner assembly 1 through one or more rows of intake holes 34 on the flame tube mounting orifice plate 31.

[0044] The head of the second air passage T2 is a flared mouth, and its inner wall forms an opening along the radial direction R with the burner head flange 14. A large part of the oncoming air between the combustion chamber casing assembly 2 and the flame tube assembly 3 enters the first air passage T1 through the intake holes 34 on the flame tube mounting orifice plate 31, and a small part enters the second air passage T2.

[0045] Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. A burner assembly, characterized in that, include: a first swirler and a first fuel pipe, wherein the first swirler has a first air passage, and the first fuel pipe is located in the first air passage; The surface of the first fuel pipe is provided with flow-turbulating patterns and a plurality of first fuel holes; The first air channel is a bent structure; The burner assembly further includes a second swirler and a second fuel pipe, the second swirler having a second air passage, the first air passage surrounding the second air passage; the second fuel pipe is located in the second air passage; The burner assembly further includes an annular fuel chamber surrounding the second air passage; along the axial direction of the first fuel pipe, a portion of the side wall of the second air passage is located between the side wall of the annular fuel chamber and the bent side wall of the first air passage; The first fuel pipe passes through two opposite side walls of the first air channel, one end of the first fuel pipe is fixedly connected to and communicates with the annular fuel chamber, and the other end is connected to a limiting fixture via a thread to clamp and fix the side wall of the second air channel.

2. The burner assembly according to claim 1, wherein, The circumferential surface of the first fuel pipe is provided with threads; The portion of the thread of the first fuel pipe located between the two side walls forms the flow-turbulating pattern; At least one end of the first fuel pipe is connected to a limiting fixing member through the threaded connection.

3. The burner assembly according to claim 2, wherein, An air inlet of the second air passage faces a direction away from the second air passage, an air outlet of the second air passage surrounds an air outlet of the first air passage, and the first fuel pipe extends in the axial direction.

4. The burner assembly according to claim 3, wherein There are multiple first fuel pipes, and the multiple first fuel pipes are distributed around the second air channel at intervals.

5. The burner assembly according to claim 3, wherein, There are a plurality of the first swirlers, and the plurality of the first swirlers are stacked in the axial direction. Each of the first fuel pipes passes through a plurality of the first air channels in sequence.

6. The burner assembly according to claim 5, wherein, Every two adjacent first air channels share one side wall.

7. The burner assembly according to claim 3, characterized in that, Also included is a head igniter, wherein a plurality of second fuel holes are distributed on the circumferential surface of the second fuel pipe; A vane assembly is provided in the second air passage, the second fuel hole is located upstream of the vane assembly, and the ignition end of the head igniter is located at the second fuel hole.

8. The burner assembly according to claim 1, characterized in that, The first fuel hole is formed with a counterbore at an opening on a surface of the first fuel pipe, and an inner diameter of the counterbore is larger than an inner diameter of the first fuel hole.

9. A combustion device, characterized in that, It comprises a casing assembly, a flame tube assembly and the burner assembly according to any one of claims 1 to 8, wherein the flame tube assembly is located inside the casing assembly, and an opening of the flame tube assembly is connected to an air outlet of the first air passage.

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