Medium calorific value synthesis gas nozzle for light gas turbine, swirler, nozzle-swirler assembly, combustion chamber and gas turbine

Abstract

The invention discloses a medium-calorific-value synthesis gas nozzle for a light gas turbine, a swirler, a nozzle-swirler assembly, a combustion chamber and the gas turbine. The nozzle comprises a nozzle main body and a nozzle head; the nozzle head comprises a cylindrical part and a circular truncated cone part which are connected in sequence; a plurality of rows of fuel spray holes are formed in the conical surface of the circular truncated cone part, a V-shaped end part arranged inwards is arranged on the upper bottom surface, and a central spray hole is formed in the middle of the circular truncated cone part. The swirler comprises a sleeve and swirling vanes, an inner cavity at the front end of the sleeve is a slow expansion section, an inner cavity at the rear end of the sleeve is a sudden expansion section, and the slow expansion section and the sudden expansion section jointly form a trumpet-shaped inner cavity. The swirl nozzle head with multiple densely distributed spraying holes is combined with the trumpet-shaped swirler sleeve, a high equivalence ratio area near the nozzle and a high flow speed area at the downstream of the nozzle can be built, and therefore nozzle ablation, synchronous swirling of fuel and air and sudden expansion flow guiding of the sleeve are avoided, and interference of the large flow characteristic of medium-heat-value fuel on swirling can be reduced; and the backflow intensity and the fuel-air mixing uniformity are obviously improved, so that the combustion is stable.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of gas turbine combustion chambers, and particularly relates to a medium-calorific-value synthetic gas nozzle, a swirler, a nozzle-swirler assembly, a combustion chamber and a gas turbine for a light gas turbine. BACKGROUND

[0002] Traditional gas turbines are mainly designed to burn high-quality fuels such as natural gas. However, the regional distribution of natural gas resources is uneven, and the price fluctuates greatly. For the sake of energy supply safety and fuel source diversity, the industry has turned its attention to more widely sourced and lower cost alternative fuels, especially various types of medium-calorific-value gas fuels. Medium-calorific-value fuels generally refer to fuels with a calorific value significantly lower than that of natural gas, with a calorific value range generally defined as 6.28-15.07 MJ / Nm 3 , less than half of the volumetric heat value of natural gas, which is generally derived from industrial byproduct gas or waste gas, biomass gas, etc., and is low in price. When used for gas turbine power generation, it not only solves the problem of waste gas treatment, but also meets the power demand of the factory.

[0003] The main application scenarios of medium-calorific-value fuel gas turbine power generation mode include overall coal gasification combined cycle power generation, biomass gasification power generation, coking and steelmaking waste gas power generation, offshore platform power generation, etc., and have great market application prospects and environmental protection value. Medium-calorific-value synthetic gas stable combustion technology is the key to the design of medium-calorific-value gas turbines. However, different sources of medium-calorific-value gas, such as biomass gas, coke oven gas, coal gas synthetic gas, coke gas, and blast furnace gas, have different components and calorific values, and their combustion characteristics differ. Currently, medium-calorific-value combustion chambers are generally designed only for one type of fuel, making it difficult to ensure the combustion of multiple fuels. Not only is the design and manufacturing cost of the combustion chamber high, but it also limits the rapid development of medium-calorific-value power generation mode. Therefore, it is necessary to design a medium-calorific-value combustion chamber that can accommodate a wide range of calorific value fuels.

[0004] In recent years, major research institutions and gas turbine manufacturers have made significant achievements in the mechanism research and demonstration application of medium-calorific-value combustion chambers. Some manufacturers' coke oven gas (volume heat value 16 MJ / m 3 ) power stations have been able to operate stably for a long time, but these combustion chambers have the following problems:

[0005] 1. Existing medium-calorific-value combustion chambers are designed only for a specific fuel, have a small application range, and cannot cover the entire medium-calorific-value range. In particular, synthetic gas with large variations in inert gas content and large differences in calorific value and Wobbe number requires a new design of combustion organization. In actual applications, the components of medium-calorific-value fuels are diverse, and the calorific value also varies within a wide range. Therefore, a combustion chamber that can achieve stable combustion of various medium-calorific-value fuels is needed.

[0006] 2. Micro-mix combustion technology is a new combustion technology suitable for hydrogen combustion, which can also be applied to medium-calorific value synthesis gas. However, the use of micro-mix combustion technology is complex in design modification, and the technology is not mature. Compared with the existing combustion chamber, the manufacturing and maintenance costs are higher, the uncertainty is high, and the diameter of the fuel micro-mix hole is in the order of millimeters, which requires strict purity of industrial by-product gas. SUMMARY

[0007] The purpose of the present application is to provide a medium-calorific value synthesis gas nozzle, a swirler, a nozzle-swirler assembly, a combustion chamber and a gas turbine for a light-duty gas turbine, which can realize stable combustion of synthesis gas in the medium-calorific value range, and the combustion chamber has the characteristics of simple structure and low manufacturing cost, and effectively solves the problem that the existing combustion chamber cannot match the combustion of multiple fuels.

[0008] To achieve the above purpose, the present application provides the following technical solutions:

[0009] In a first aspect, the present application provides a medium-calorific value synthesis gas nozzle for a light-duty gas turbine, which comprises a nozzle body and a nozzle head, and the nozzle head comprises a cylindrical part and a circular truncated cone part connected in sequence; a plurality of rows of fuel injection holes are arranged on the conical surface of the circular truncated cone part, the upper bottom surface is provided with a V-shaped end portion inward, and the central part is provided with a central injection hole.

[0010] As a specific solution in the technical solution of the present application, the outer side of the V-shaped end portion is a first V-shaped end face, and the inner side is a second V-shaped end face, and the taper angle of the first V-shaped end face is not less than the taper angle of the second V-shaped end face.

[0011] Preferably, the depth of the first V-shaped end face is not less than one-fourth of the length of the circular truncated cone part.

[0012] More preferably, the depth of the second V-shaped end face is not less than the length of the circular truncated cone part, and not more than one-half of the total length of the cylindrical part and the circular truncated cone part.

[0013] As a specific solution in the technical solution of the present application, the taper angle of the circular truncated cone part is 80-100°; preferably, the taper angle of the V-shaped end portion is not greater than the taper angle of the circular truncated cone part.

[0014] As a specific solution in the technical solution of the present application, the central injection hole is a straight injection hole opened along the central axis of the nozzle head.

[0015] As a specific scheme in the technical scheme of the present application, the center injection hole is a plurality of bevel holes formed on the side of the V-shaped end portion, and the bevel angle direction is the same as the rotation direction of the cyclone vane; preferably, the projection of the center line of the bevel hole on the longitudinal section is at an angle of not more than half of the cone angle of the circular truncated cone portion, and the bevel angle of the bevel hole is between 15-20°.

[0016] As a specific scheme in the technical scheme of the present application, at least three rows of fuel injection holes are arranged on the conical surface of the circular truncated cone portion, at least two rows of which are bevel holes with a bevel angle α of 20-30°, the bevel angle direction is the same as the direction of the cyclone vane, and the spacing of the multiple rows of holes in the radial direction is the same; the diameter of the fuel injection hole is selected to ensure that the fuel-air momentum flux ratio is not more than 6 and not less than 2.

[0017] As a specific scheme in the technical scheme of the present application, three rows of fuel injection holes are arranged on the conical surface of the circular truncated cone portion, all of which are bevel holes with a bevel angle of 30°; and / or,

[0018] The diameter of the fuel injection hole is 2.5-3.2mm, and / or,

[0019] The radial spacing between the fuel injection holes is 3-3.5mm.

[0020] In a second aspect, the present application provides a cyclone for the above-mentioned medium-calorific-value synthetic gas nozzle, which comprises a sleeve and a cyclone vane, the sleeve comprises a sleeve front end and a sleeve rear end, the inner cavity of the sleeve front end is a slowly expanding section, and the inner cavity of the sleeve rear end is a suddenly expanding section, together forming a trumpet-shaped sleeve inner cavity.

[0021] As a specific scheme in the technical scheme of the present application, the ratio of the expansion angles of the sleeve rear end and the sleeve front end is 6-22.5:1, and the ratio of the lengths of the sleeve front end and the sleeve rear end is 3-5:1;

[0022] Preferably, the single-side expansion angle of the sleeve front end is between 2-5°, and the length is 20-25mm; the single-side expansion angle of the sleeve rear end is between 30-45°, and the length is 4.5-6mm;

[0023] As a specific scheme in the technical scheme of the present application, the flow area of the cyclone vane of the cyclone accounts for 18-20% of the total air flow area in the combustion chamber.

[0024] In a third aspect, the present application further provides a medium-calorific-value synthetic gas nozzle-cyclone assembly for a light-duty gas turbine, which is composed of the above-mentioned nozzle and the above-mentioned matching cyclone.

[0025] In a fourth aspect, the application further provides a medium-calorific-value synthetic gas combustion chamber for a light-duty gas turbine, which comprises a flame tube casing, a flame tube, and the nozzle and the swirler described above; wherein the nozzle is connected with the swirler, the nozzle head of the nozzle is arranged in the swirler, the swirler is arranged at the head of the flame tube, the flame tube is arranged in the flame tube casing, and the flame tube is sequentially provided with main combustion holes and mixing holes along the head-to-tail direction; and the flame tube casing, the flame tube, the swirler, and the nozzle head are coaxially arranged.

[0026] As a specific solution in the technical scheme of the application, the inlet direction of the swirler is along the conical surface of the nozzle head, and forms an angle of 40-50° with the axis of the flame tube; preferably, the inlet direction of the swirler is perpendicular to the fuel jet direction of the nozzle, parallel to the conical surface of the nozzle head, and forms an angle of 45° with the axis of the flame tube.

[0027] As a specific solution in the technical scheme of the application, the main combustion holes and the mixing holes on the flame tube are uniformly arranged along the circumferential direction on the tube wall, respectively, the area of the main combustion holes accounts for 22-24% of the total airflow passage area in the combustion chamber, and the area of the mixing holes accounts for 18-20% of the total airflow passage area in the combustion chamber, respectively.

[0028] In a fourth aspect, the application further provides a gas turbine comprising the medium-calorific-value synthetic gas combustion chamber described above.

[0029] Compared with the prior art, the application has the following beneficial effects:

[0030] (1) Compared with the existing synthetic gas combustion chamber, the combustion chamber and the method provided by the application can burn synthetic gas in the entire medium-calorific-value range, and have good fuel flexibility.

[0031] (2) Compared with other medium-calorific-value combustion chambers, the combustion chamber has a very simple structure, has good manufacturing and use economy, and can be used for the modification of existing natural gas combustion chambers.

[0032] (3) The multi-nozzle densely arranged swirled nozzle head design combined with the unique "horn-shaped" swirler sleeve structure can create a high equivalence ratio area near the nozzle and a high flow velocity area downstream of the nozzle to avoid nozzle ablation, and can reduce the disturbance to the swirling flow caused by the large flow characteristics of the medium-calorific-value fuel, significantly improve the backflow strength and the fuel-air mixing uniformity, and enable the combustion chamber to achieve high-efficiency combustion even when burning some synthetic gas with low reactivity, and has good combustion stability. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 Fig. 1 is a cross-sectional schematic view of a gas turbine combustion chamber for the high-efficiency and stable combustion of medium-calorific-value synthetic gas according to Embodiment 1 of the application;

[0034] Figure 2 is Figure 1 is a local enlarged view of A in

[0035] Figure 3 is a schematic view of a nozzle assembly structure according to an embodiment of the present application;

[0036] Figure 4 is a schematic view of a nozzle head frustum structure according to an embodiment of the present application;

[0037] Figure 5 is a schematic view of a nozzle assembly structure according to another embodiment of the present application;

[0038] Figure 6 is a local enlarged view of A in Figure 5 is a schematic view of a nozzle head frustum structure according to the nozzle assembly shown in

[0039] Figure 7 is a schematic view of a nozzle head frustum structure according to yet another embodiment of the present application;

[0040] Figure 8 is a schematic view of a swirler structure according to an embodiment of the present application;

[0041] Figure 9 is a schematic view of a fuel hole arrangement scheme according to an embodiment of the present application.

[0042] Reference signs are as follows:

[0043] 1 - nozzle body;

[0044] 2 - nozzle head; 201 - fuel hole; 202 - center hole; 203 - first V-shaped end face; 204 - cylindrical portion; 205 - frustum portion; 206 - second V-shaped end face;

[0045] 3 - flame tube case;

[0046] 4 - flame tube;

[0047] 5 - main combustion hole;

[0048] 6 - mixing hole;

[0049] 7 - combustion chamber outlet;

[0050] 8 - air ring cavity;

[0051] 9 - sleeve; 901 - sleeve front end; 902 - sleeve rear end;

[0052] 10 - swirler blade;

[0053] 11 - fuel inlet. DETAILED DESCRIPTION

[0054] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of the present application.

[0055] It should be noted that, in the description of the present application, the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0056] In addition, it should be understood that the features in the same and different embodiments of the present application can be combined with each other without conflict.

[0057] It should also be understood that, for the convenience of description, the sizes of the various components shown in the drawings are not drawn in accordance with the actual proportional relationship, for example, the thickness or width of certain layers can be exaggerated relative to other layers.

[0058] It should be noted that similar reference numbers and letters represent similar items in the following drawings, and therefore, once an item is defined or described in one drawing, it will not need to be further specifically discussed and described in the description of subsequent drawings.

[0059] In a first aspect, to solve the problem that the existing fuel nozzle and combustion chamber in the prior art cannot match multiple fuel combustion, an embodiment of a medium-calorific-value synthetic gas nozzle for a light-duty gas turbine is provided. Specifically, referring to Figure 1 , Figures 3-4 The nozzle comprises a nozzle body 1 and a nozzle head 2, the nozzle head 2 comprises a cylindrical portion 204 and a circular frustum portion 205 connected in sequence, a plurality of rows of fuel injection holes 201 are arranged on the conical surface of the circular frustum portion 205, and a V-shaped end portion is arranged inwardly at the upper bottom surface of the circular frustum portion 205, and a central injection hole 202 is arranged in the middle portion.

[0060] The medium-calorific-value synthetic gas in the present application refers to a multi-component synthetic gas fuel with a volume calorific value of 6-15 MJ / m 3 The main components include hydrogen, carbon monoxide, methane, nitrogen and carbon dioxide, wherein the total volume percentage of hydrogen and carbon monoxide is 40%-95%, the volume percentage of hydrogen is not more than 50%, and the total volume percentage of nitrogen and carbon dioxide is not more than 50%.

[0061] In the embodiments of the present application, the nozzle head 2 has a "cylinder + circular truncated cone" structure, wherein the cylindrical part 204 is connected with the swirler, and the circular truncated cone part 205 extends into the swirler. The surface of the circular truncated cone part 205 is provided with fuel injection holes, including a plurality of rows of fuel injection holes 201 arranged on the conical surface. Preferably, the conical angle of the circular truncated cone part 205 is between 80-100° (such as 80°, 82°, 85°, 90°, 95°, 98°, 100°, etc.). The upper bottom surface of the circular truncated cone part 205 is a V-shaped end portion recessed towards the inside of the circular truncated cone part 205, which looks like a letter V in the longitudinal section, and the outer side surface is a first V-shaped end surface 203, and the inner side surface is a second V-shaped end surface 206. The conical angle of the first V-shaped end surface 203 is not less than the conical angle of the second V-shaped end surface 206, as shown in Figures 3 to 7 .

[0062] Preferably, the conical angle of the V-shaped end portion is not greater than the conical angle of the circular truncated cone part 205.

[0063] Preferably, the depth of the first V-shaped end surface 203 is not less than one fourth of the length of the circular truncated cone part 205, which can effectively reduce the area of the upper bottom surface of the circular truncated cone part 205 directly contacting the flame.

[0064] Preferably, the depth of the second V-shaped end surface 206 (i.e. the protrusion height of the inner side of the nozzle) is not less than the length of the circular truncated cone part 205, and not greater than one half of the total length of the cylindrical part 204 and the circular truncated cone part 205. In this way, the second V-shaped end surface 206 can better play a role in regulating the flow field inside the nozzle, guiding the fuel to flow uniformly along the conical inner end surface to the plurality of rows of fuel injection holes 201 on the conical surface of the circular truncated cone part 205.

[0065] In addition, at least one center injection hole 202 is arranged in the middle of the V-shaped end portion, forming a local fuel-rich zone, which is used to prevent the flame from adhering to the end surface and further avoid nozzle ablation. Specifically, the center injection hole 202 can be a straight injection hole (see Figure 4 and Figure 6 ) opened along the central axis of the nozzle head. The center injection hole 202 can also be a plurality of oblique cutting holes (see Figure 7 ) opened on the side surface of the V-shaped end portion (penetrating the first V-shaped end surface 203 and the second V-shaped end surface 206). Preferably, the projection of the center line of the oblique cutting hole on the longitudinal section of the V-shaped end portion has an angle with the center line of the circular truncated cone part 205 not greater than half of the conical angle of the V-shaped end portion; the oblique angle (the angle between the center line of the oblique cutting hole and the longitudinal section of the V-shaped end portion) is between 15-20°, and the direction of the oblique angle is the same as the direction of rotation of the swirler blade, which is more easy to form a local fuel-rich zone, prevent the flame from adhering to the end surface, and further avoid nozzle ablation.

[0066] Further, at least three rows of fuel injection holes 201 are arranged on the conical surface of the circular truncated cone part 205, as shown in Figure 9As shown in the figure, at least two rows of the holes are beveled, wherein the arrow represents the direction of the beveled holes, i.e. the direction of fuel rotation, and the fuel is sprayed in a clockwise rotation in use, the bevel angle a (the angle between the center line of the beveled hole and the longitudinal section of the frustum) is between 20-30°, the direction of the bevel angle is the same as the direction of the swirler blade rotation, which ensures the same direction of rotation, the distance of the multiple rows of holes in the radial direction is the same, which ensures that the fuel injection holes 201 are uniformly distributed on the conical surface and fully utilize the conical surface space. For the selection of the fuel injection hole diameter, it is necessary to ensure that the fuel and air momentum flux ratio is not more than 6 and not less than 2, so as to prevent the fuel and air from being mixed unevenly due to the too fast fuel jet speed and too large jet depth, and the fuel supply pressure will also be large; or prevent backfire from causing the nozzle to be ablated due to the too slow fuel jet speed.

[0067] The fuel and air momentum flux ratio is defined as:

[0068]

[0069] Wherein, ρ fuel , μ fuel respectively represent the density and speed of the fuel jet, ρ air , μ air respectively represent the density and speed of the air flow. Generally, the average speed of the fuel injection hole and the swirler outlet is selected as the speed of the fuel and air.

[0070] In some specific preferred examples, three rows of fuel injection holes 201 are arranged on the conical surface of the frustum 205, all of which are beveled holes, and the angle of the bevel angle is 30°; the diameter of the fuel injection hole 201 is 2.5-3.2mm, and the radial distance between the fuel injection holes 201 is 3-3.5mm.

[0071] In a second aspect, the application also proposes an embodiment of a swirler used with the above-mentioned medium-calorific-value synthetic gas nozzle.

[0072] Specifically, the swirler is a tower-type swirler, and the direction of the swirler inlet is along the conical surface of the nozzle head and forms a certain angle with the axis of the flame tube, such as 40-50°, and generally the direction of the swirler inlet is perpendicular to the direction of the fuel jet of the nozzle and parallel to the conical surface of the nozzle head. The swirler includes a sleeve 9 and a swirler blade 10. As shown in the figure, Figure 1 、 Figure 3 、 Figure 5As shown, the sleeve 9 of the swirler includes a sleeve front end 901 and a sleeve rear end 902, and has a similar "horn shape" structure, that is, the inner cavity of the sleeve front end 901 is a slowly expanding section, and the inner cavity of the sleeve rear end 902 is a suddenly expanding section, which together form a horn-shaped sleeve inner cavity. Among them, the expansion angle of the sleeve front end 901 is small, and the main role is to maintain the flow rate and suppress backfire, and the expansion angle of the sleeve rear end 902 suddenly increases, which plays a role of guiding flow expansion. Because the mass flow of the medium-calorific-value synthetic gas fuel is large and close to the air intake of the swirler, "blockage" phenomenon occurs in the sleeve, and the suddenly expanding structure can reduce the restriction of the sleeve 9 on the main flow swirler expansion, guide the development of the gas flow to form a "blossom-shaped" backflow area B (see Figure 1 ). At the same time, the nozzle fuel and the swirler air rotate in the same direction, reducing the interference between the fuel and the air, and realizing the flow field organization demand of large flow in a small space. The flame propagation speed of the medium-calorific-value synthetic gas with a high volume ratio of hydrogen and carbon monoxide is very fast. In one aspect, the present application is designed to reduce the direct contact flame area by distributing fuel injection holes on the nozzle head cone surface, designing a recessed end surface, and opening a hole in the center of the end surface, so that the synthetic gas is uniformly injected from each position on the nozzle surface. The fuel concentration is large near the entire nozzle head to form a natural high equivalence ratio "protective layer", and the multi-hole injection can make the medium-calorific-value fuel mix more uniformly with air in the flame tube. On the other hand, the expansion angle of the sleeve rear end 902 is suddenly increased, which plays a role of guiding flow expansion. Because the mass flow of the medium-calorific-value synthetic gas fuel is large and close to the air intake of the swirler, "blockage" phenomenon occurs in the sleeve, and the suddenly expanding structure can reduce the restriction of the sleeve 9 on the main flow swirler expansion, guide the development of the gas flow to form a "blossom-shaped" backflow area B (see

[0073] In the embodiments of the present application, preferably, the ratio of the expansion angle of the sleeve rear end 902 to the sleeve front end 901 is 6-22.5:1, and the length ratio of the sleeve front end 901 to the sleeve rear end 902 is 3-5:1.

[0074] In some specific preferred examples, the expansion angle of the sleeve front end 901 is small, and the single-side expansion angle is between 2-5° (such as 2°, 3°, 4°, 5°, etc.), and the length is 20-25 mm (such as 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, 25 mm, etc.), which can better maintain the flow rate and suppress backfire; the expansion angle of the sleeve rear end 902 is suddenly increased, and the single-side expansion angle is between 30-45° (such as 30°, 32°, 35°, 40°, 42°, 45°, etc.), and the inventors have found that a reasonable value in this interval can ensure that the sleeve rear end 902 and the flame tube 4 do not overheat; the length of the sleeve rear end 902 is 4.5-6 mm (such as 4.5 mm, 5.0 mm, 5.5 mm, 6 mm, etc.).

[0075] In the embodiment of the present application, preferably, the flow area of the swirl vane 10 of the swirler accounts for 18-20% of the total air flow area in the combustion chamber, which is higher than the design value of the general conventional diffusion combustion chamber, and when the synthetic gas with high heat value contains more inert gas, the fuel flow is large and the combustion temperature is low, the equivalence ratio of the head part can be controlled to be between 1-1.1, and the combustion stability is ensured.

[0076] In a third aspect, the present application further provides an embodiment of the combustion chamber for the synthetic gas with high heat value used in the light gas turbine.

[0077] Specifically, the combustion chamber comprises a flame tube casing 3, a flame tube 4, and the above-mentioned nozzle and swirler provided by the present application. Figure 1 、 Figure 2 As shown in the figure, in the combustion chamber, the nozzle is connected with the swirler, the nozzle head 2 of the nozzle is arranged in the swirler, the swirler is arranged at the head part of the flame tube 4, the flame tube 4 is arranged in the flame tube casing 3, and the main combustion holes 5 and the mixing holes 6 are arranged on the flame tube 4 in sequence from the head part to the tail part; the flame tube casing 3, the flame tube 4, the swirler and the nozzle head 2 are coaxially arranged.

[0078] In the embodiment of the present application, the air inlet direction of the swirler is along the conical surface of the nozzle head, and forms a certain angle with the axis of the flame tube, for example, 40-50°, and more specifically, generally, the air inlet direction of the swirler is perpendicular to the fuel jet direction of the nozzle, parallel to the conical surface of the nozzle head, and the included angle with the axis of the flame tube 4 is 45°.

[0079] In the embodiment of the present application, the main combustion holes 5 and the mixing holes 6 on the flame tube 4 are arranged uniformly in the circumferential direction on the wall of the flame tube, the area of the main combustion holes 5 accounts for 22-24% of the total gas flow area in the combustion chamber, and the area of the mixing holes 6 accounts for 18-20% of the total gas flow area in the combustion chamber respectively, so as to ensure sufficient jet depth and good outlet performance (such as uniformity of the outlet temperature of the combustion chamber).

[0080] When the combustion chamber with high heat value synthetic gas provided by the present application is used, natural gas is used for ignition, and after the ignition is successful, the fuel conversion is completed within the full speed no load to 30% load.

[0081] The combustion chamber provided by the present application adopts the combustion organization method of fuel swirl injection and guided main flow expansion, effectively expands the heat value range of the combustion chamber using the synthetic gas with high heat value, and is suitable for the synthetic gas fuel with medium heat value between 6-15 MJ / m 3 .

[0082] Embodiment 1

[0083] As shown in the figure, in the combustion chamber, the nozzle is connected with the swirler, the nozzle head 2 of the nozzle is arranged in the swirler, the swirler is arranged at the head part of the flame tube 4, the flame tube 4 is arranged in the flame tube casing 3, and the main combustion holes 5 and the mixing holes 6 are arranged on the flame tube 4 in sequence from the head part to the tail part; the flame tube casing 3, the flame tube 4, the swirler and the nozzle head 2 are coaxially arranged. Figures 1-6As shown, this embodiment provides a medium-calorific-value syngas nozzle and combustion chamber for a light-duty gas turbine, wherein the combustion chamber is specifically designed for syngas with a calorific value of 6 MJ / m³. 3 Up to 15 MJ / m 3 The gas turbine combustor designed for combustion of medium-calorific-value syngas includes a nozzle, a swirler, a flame tube housing 3, and a flame tube 4. The nozzle comprises a nozzle body 1 and a nozzle head 2 connected thereto, the nozzle head 2 being installed within the swirler. The swirler includes swirling blades 10 and a trumpet-shaped sleeve 9, and is installed at the head of the flame tube 4. The flame tube 4 has a main combustion port 5 and a mixing port 6 sequentially formed on its wall from head to tail. The flame tube 4 is housed within the flame tube housing 3, forming an air annular cavity 8 between the flame tube housing 3 and the flame tube 4. The nozzle, swirler, flame tube 4, and flame tube housing 3 are coaxially arranged. The air inlet direction of the swirler is along the nozzle cone surface, forming a 45° angle with the axis of the flame tube 4.

[0084] During operation, air flows in from the rear of the combustion chamber and flows towards the head of the flame tube 4 within the air annular cavity 8. It enters the combustion chamber through the mixing hole 6, the main combustion hole 5, and the swirler, respectively. The swirler causes the outflowing air to swirl. Fuel flows in from the fuel inlet 11 on the nozzle body 1 and is ejected from the fuel nozzle 201 on the nozzle head 2, mixing with the swirling air to form a fuel-air mixture. The reflux zone B formed by the swirling shearing action of the swirler and the main combustion hole 5 will entrain the high-temperature combustion products to serve as a stable ignition source, thereby stabilizing the flame and preventing it from being blown out. When the high-temperature combustion gas reaches the mixing hole 6, it is mixed with the air jet flowing in through the mixing hole 6 to meet the turbine inlet index requirements and is discharged through the combustion chamber outlet 7.

[0085] In this embodiment, see Figure 6 The nozzle head 2 includes a cylindrical portion 204 and a frustum portion 205 connected in sequence. Three rows of fuel injection holes 201 are provided on the conical surface of the frustum portion 205, all of which are obliquely cut holes with an oblique angle of 30°. The radial spacing between the three rows of holes is between 3 and 3.5 mm, and the diameter of the fuel injection holes 201 is between 2.5 and 3.2 mm. The fuel injection holes 201 are evenly and densely distributed on the conical surface to fully utilize the space. In this embodiment, the fuel injected from the fuel injection holes 201 on the nozzle head 2 has a swirling motion effect, with the rotation direction being the same as the air swirling direction of the swirler. This guides the fuel-air mixture to form a full recirculation zone, reducing the interference effect caused by the high-calorific-value fuel flow on the swirling air and avoiding affecting the development of the recirculation zone and combustion stability. Simultaneously, it promotes fuel-air mixing and increases fuel residence time. For medium-calorific-value syngas with a low volumetric calorific value, which often contains more inert gases and has low reactivity, a longer residence time and stronger mixing are required in the combustion chamber to ensure combustion efficiency. Therefore, the solution in this embodiment is particularly suitable for this situation.

[0086] In this embodiment, referring to Figure 2 and Figure 5 , the sleeve 9 of the swirler is similar to a horn structure, the single-side expansion angle of the front end 901 of the sleeve (i.e. the included angle between the inner side generatrix of the front end 901 of the sleeve and the sleeve axis) is taken as a suitable value between 2-5°, and the length is taken as a suitable value between 20-25mm, the main function is to maintain the fuel air flow rate to suppress backfire, the single-side expansion angle of the rear end 902 of the sleeve (i.e. the included angle between the inner side generatrix of the rear end 902 of the sleeve and the sleeve axis) is taken as a suitable value between 30-45°, and the length is taken as a suitable value between 4.5-6mm, about one fourth of the length of the front end 901 of the sleeve, the design plays a role of flow guiding and expansion, which helps to develop the swirl and form Figure 1 the "blossom-shaped" backflow area B shown in the front streamline of the main combustion hole 5, the full backflow area structure can further increase the residence time of the reactants and the strength of the high-temperature combustion products, which is beneficial to the stable and sufficient combustion of the fuel.

[0087] The upper bottom surface of the circular truncated cone part 205 of the nozzle head 2 is a V-shaped end portion concave inward, the outer side is a first V-shaped end surface 203, and the inner side is a second V-shaped end surface 206, and a center injection hole 202 is arranged in the middle of the V-shaped end portion. The conical surface of the circular truncated cone part 205 of the nozzle head 2 is uniformly and densely provided with fuel injection holes 201, the upper bottom surface of the circular truncated cone part 205 is designed as a V-shaped end surface, and a center injection hole 202 is arranged in the middle of the V-shaped end surface, so that the synthesis gas is uniformly injected from each position on the surface of the nozzle head 2, and a natural high equivalence ratio "protective layer" is formed near the entire nozzle head 2 with a large fuel concentration, and the nozzle is not ablated. The effective organization of the medium-calorific-value synthesis gas combustion flow field in this embodiment is completed by the superposition of the double design effects of the nozzle head 2 and the swirler sleeve 9, and neither of them can be omitted.

[0088] The main combustion holes 5 and the mixing holes 6 on the wall of the flame tube 4 are uniformly arranged along the circumference, and the areas of the main combustion holes 5 and the mixing holes 6 account for 24% and 20% of the total airflow flow area in the combustion chamber respectively, and the flame tube does not need to be lengthened compared with the traditional natural gas combustion chamber.

[0089] Although the embodiments of the present application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A medium-calorific-value syngas nozzle for a light-duty gas turbine, characterized in that, It includes a nozzle body and a nozzle head. The nozzle head includes a cylindrical part and a frustum part connected in sequence. The frustum part has multiple rows of fuel injection holes on its conical surface, and the upper bottom surface has an inwardly arranged V-shaped end with a central injection hole in its middle.

2. The medium-calorific-value syngas nozzle according to claim 1, characterized in that, The outer side of the V-shaped end is the first V-shaped end face, and the inner side is the second V-shaped end face. The cone angle of the first V-shaped end face is not less than the cone angle of the second V-shaped end face. Preferably, the depth of the first V-shaped end face is not less than one-quarter of the length of the frustum portion; More preferably, the depth of the second V-shaped end face is not less than the length of the frustum portion, and not greater than half the total length of the cylindrical portion and the frustum portion.

3. The intermediate calorific value synthesis gas nozzle according to claim 1 or 2, characterized in that, The cone angle of the frustum portion is 80 to 100°; preferably, the cone angle of the V-shaped end is not greater than the cone angle of the frustum portion.

4. The medium-calorific-value synthesis gas nozzle according to any one of claims 1-3, characterized in that, The central nozzle is a straight nozzle formed along the central axis of the nozzle head; or, The central nozzle is a plurality of oblique holes opened on the side of the V-shaped end, with the oblique angle direction being in the same direction as the rotation direction of the hydrocyclone blades; preferably, the angle between the projection of the center line of the oblique hole on the longitudinal section and the center line of the frustum is not greater than half of the cone angle of the V-shaped end, and the oblique angle of the oblique hole is between 15 and 20°.

5. The medium-calorific-value synthesis gas nozzle according to any one of claims 1-4, characterized in that, At least three rows of fuel injection holes are arranged on the conical surface of the frustum, of which at least two rows are obliquely cut holes with an oblique angle α between 20 and 30°. The direction of the oblique angle is the same as the direction of the hydrocyclone blades, and the spacing between the multiple rows of holes in the radial direction is the same. The selection of the diameter of the fuel injection holes should ensure that the fuel-to-air momentum flux ratio does not exceed 6 and is not less than 2. Optionally, three rows of fuel injection holes are arranged on the conical surface of the frustum, all of which are obliquely cut holes with an oblique angle of 30°; and / or, The diameter of the fuel injection orifice is 2.5-3.2 mm, and / or, The radial spacing between the fuel injection holes is 3-3.5 mm.

6. A cyclone separator for use with a medium-calorific-value synthesis gas nozzle according to any one of claims 1-5, characterized in that, It includes a sleeve and swirl blades. The sleeve includes a front end and a rear end. The inner cavity of the front end of the sleeve is a slow-expansion section, and the inner cavity of the rear end of the sleeve is a sudden-expansion section, which together form a trumpet-shaped inner cavity of the sleeve. Preferably, the ratio of the expansion angle of the rear end of the sleeve to that of the front end of the sleeve is 6-22.5:1, and the ratio of the length of the front end of the sleeve to that of the rear end of the sleeve is 3-5:

1. Preferably, the single-sided expansion angle of the front end of the sleeve is between 2 and 5°, and the length is 20 to 25 mm; the single-sided expansion angle of the rear end of the sleeve is between 30 and 45°, and the length is 4.5 to 6 mm. Preferably, the flow area of ​​the swirling blades of the swirling device accounts for 18-20% of the total air flow area in the combustion chamber.

7. A mezzanine syngas nozzle-cyclone assembly for a light-duty gas turbine, comprising a mezzanine syngas nozzle according to any one of claims 1-5 and a cyclone according to claim 6.

8. A medium-calorific-value syngas combustion chamber for a light-duty gas turbine, characterized in that, The combustion chamber includes: a flame tube housing, a flame tube, and a nozzle as described in any one of claims 1-5, and a swirler as described in claim 6; wherein the nozzle is connected to the swirler, and the nozzle head of the nozzle is disposed within the swirler; the swirler is disposed at the head of the flame tube, and the flame tube is disposed within the flame tube housing, with a main combustion port and a mixing port sequentially arranged along the head to tail direction on the flame tube; the flame tube housing, the flame tube, the swirler, and the nozzle head are coaxially arranged.

9. The medium-calorific-value syngas combustion chamber according to claim 8, characterized in that, The cyclone separator's air inlet direction is along the conical surface of the nozzle head, forming an angle of 40-50° with the flame tube axis; preferably, the cyclone separator's air inlet direction is perpendicular to the nozzle fuel jet direction, parallel to the nozzle head's conical surface, and forms an angle of 45° with the flame tube axis; and / or, The main combustion holes and mixing holes on the flame tube are evenly arranged circumferentially on the tube wall. The area of ​​the main combustion holes accounts for 22-24% of the total airflow area in the combustion chamber, and the area of ​​the mixing holes accounts for 18-20% of the total airflow area in the combustion chamber.

10. A gas turbine, characterized in that, Includes the medium-calorific-value syngas combustion chamber as described in claim 8 or 9.

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