Dry low-emission combustion chamber of gas turbine and control method of dry low-emission combustion chamber

Abstract

The invention belongs to the technical field of combustion chamber design of gas turbines, and particularly relates to a dry low-emission combustion chamber of a gas turbine and a control method of the dry low-emission combustion chamber of the gas turbine, the low-emission working condition range of the gas turbine is widened by adopting a multi-stage staged supply combustion form of air and fuel, and the stability of ignition and combustion can be ensured.

Description

Technical Field

[0001] The present application belongs to the technical field of gas turbine combustion chamber design, and specifically relates to a gas turbine dry low-emission combustion chamber and a control method thereof. Background Art

[0002] Dry low-emission combustion technology is based on the Zel'dovich generation principle of thermal NOx. It achieves low NOx emission control by constraining the flame temperature in the main combustion zone within a narrow range of 1670-1900K and is widely used in gas turbine combustors.

[0003] At present, most dry low-emission combustion chambers are simply divided into two stages: main combustion stage and pre-combustion stage, which can achieve 0.8-1.0 working condition emissions to meet national standards. However, under the new trend, it is required that emissions above 0.5 conditions must meet the standards. In view of this, this application is filed. Summary of the invention

[0004] The purpose of this application is to provide a gas turbine dry low-emission combustion chamber and a control method thereof, so as to broaden the range of low-emission operating conditions and achieve emission compliance above 0.5 conditions.

[0005] The technical solution of this application is:

[0006] On the one hand, a gas turbine dry low emission combustor is provided, comprising:

[0007] Combustion chamber casing;

[0008] The flame tube is arranged in the combustion chamber casing;

[0009] The outlet of the venturi tube is connected to the inlet of the flame tube;

[0010] The main combustion secondary premixing chamber is arranged in the combustion chamber casing, and the outlet is connected to the inlet of the venturi;

[0011] The main fuel secondary cyclone is arranged in the main fuel secondary premixing chamber;

[0012] The primary premixing chamber of the main combustion is connected to the inner side of the secondary premixing chamber of the main combustion, and is arranged parallel to the secondary premixing chamber of the main combustion in the radial direction;

[0013] The primary cyclone of the main combustion is arranged in the primary premixing chamber of the main combustion;

[0014] The primary fuel first stage nozzle is arranged at the inlet of the primary fuel first stage premixing chamber;

[0015] The main fuel secondary nozzle is arranged at the inlet of the main fuel secondary premixing chamber;

[0016] The pre-combustion premixing chamber is connected to the inner side of the primary premixing chamber of the main combustion, and is arranged in parallel with the primary premixing chamber of the main combustion and the secondary premixing chamber of the main combustion in the radial direction;

[0017] The nozzle assembly is arranged in the pre-combustion pre-mixing chamber, and a central duty spray hole and a plurality of fuel diffusion spray holes and purge air holes distributed along the circumferential direction are arranged at the rear end, and each fuel diffusion spray hole is located outside the purge air hole;

[0018] The pre-combustion stage swirler is arranged in the pre-combustion premixing chamber and sleeved on the rear end of the nozzle assembly;

[0019] A plurality of pre-combustion pre-mixing spray rods are arranged in the pre-combustion pre-mixing chamber and inserted at the front end of the nozzle assembly along the circumferential direction.

[0020] According to at least one embodiment of the present application, in the above-mentioned gas turbine dry low emission combustion chamber, the inlet of the venturi is a convergent section, and the outlet is an expansion section;

[0021] The convergent section is conical and single-walled;

[0022] The expansion section is conical and has a double-wall structure, with the inner wall and the outer wall being arranged in parallel;

[0023] The outer wall of the expansion section is provided with a plurality of impingement cooling holes distributed along the axial direction, and the outlet end is bent outward and connected to the inner side of the flame tube inlet;

[0024] The outlet end of the inner wall of the expansion section is bent backward to form an annular cooling flow gap with the inner side of the flame tube inlet, and the outer wall of the outlet end of the inner wall of the expansion section is provided with an annular reinforcement protrusion.

[0025] According to at least one embodiment of the present application, in the above-mentioned gas turbine dry low-emission combustion chamber, the main combustion first-stage swirler adopts a weak swirl design.

[0026] According to at least one embodiment of the present application, in the above-mentioned gas turbine dry low-emission combustion chamber, the main fuel secondary nozzle and the main fuel primary nozzle are connected to the same pipeline, passing through to the outside of the combustion chamber casing, and connected to an external fuel source.

[0027] According to at least one embodiment of the present application, in the above-mentioned gas turbine dry low emission combustion chamber, the front end of the nozzle assembly can be connected to the inlet of the combustion chamber casing through a support plate.

[0028] According to at least one embodiment of the present application, in the above-mentioned gas turbine dry low emission combustion chamber, each fuel diffusion nozzle hole is inclined outward.

[0029] According to at least one embodiment of the present application, in the above-mentioned gas turbine dry low emission combustion chamber, the central duty spray hole is connected to an external fuel source through a duty fuel channel opened in the nozzle assembly through a pipeline from the front end of the nozzle assembly.

[0030] According to at least one embodiment of the present application, in the above-mentioned gas turbine dry low-emission combustion chamber, each fuel diffusion nozzle hole is connected to the fuel connecting channel opened in the front end of the nozzle assembly through an annular fuel channel opened in the rear end of the nozzle assembly, and is connected to an external fuel source through a pipeline from the front end of the nozzle assembly.

[0031] According to at least one embodiment of the present application, in the above-mentioned gas turbine dry low emission combustion chamber, each purge air hole is connected to the air connecting channel opened in the front end of the nozzle assembly through an annular air channel opened in the rear end of the nozzle assembly, and is connected to the air in the combustion chamber casing through an opening on the side wall of the front end of the nozzle assembly.

[0032] On the other hand, a method for controlling a dry low-emission combustor of a gas turbine is provided, which is used to control the dry low-emission combustor of the gas turbine, comprising:

[0033] When the gas turbine is started and ignited to the slow running state, the fuel is sprayed into the pre-combustion premixing chamber through each fuel diffusion nozzle to perform diffusion combustion;

[0034] When the gas turbine completes the small operating condition in the slow running state, the fuel injected into the pre-combustion pre-mixing chamber through each fuel diffusion nozzle is controlled to be reduced to zero, and the fuel is injected into the pre-combustion pre-mixing chamber through each pre-combustion pre-mixing nozzle rod and the central duty nozzle;

[0035] As the gas turbine operating condition rises to the maximum operating condition, the main fuel first-stage nozzle and the main fuel second-stage nozzle are controlled in sequence to spray fuel into the main combustion first-stage premixing chamber and the main combustion second-stage premixing chamber for premixed combustion. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a schematic diagram of a dry low-emission combustion chamber of a gas turbine provided in an embodiment of the present application;

[0037] Figure 2 It is a partial schematic diagram of a flame tube and a venturi provided in an embodiment of the present application;

[0038] Figure 3 is a schematic diagram of a nozzle assembly provided in an embodiment of the present application;

[0039] in:

[0040] 1-combustion chamber casing; 2-flame tube; 3-venturi; 4-primary premixing chamber for main combustion; 5-primary swirler for main combustion; 6-secondary premixing chamber for main combustion; 7-secondary swirler for main combustion; 8-primary nozzle for main fuel; 9-secondary nozzle for main fuel; 10-pre-combustion premixing chamber; 11-pre-combustion stage swirler; 12-pre-combustion premixing spray rod; 13-nozzle assembly;

[0041] A-Center duty nozzle; B-Fuel diffusion nozzle; C-Purge air hole.

[0042] In order to better illustrate the present embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. In addition, the drawings are only used for illustrative purposes and should not be construed as limitations on the present application. DETAILED DESCRIPTION

[0043] In order to make the technical solution and advantages of the present application clearer, the technical solution of the present application will be described in further detail in detail and in detail with reference to the accompanying drawings. It can be understood that the specific embodiments described here are only partial embodiments of the present application, which are only used to explain the present application, not to limit the present application. It should be noted that, for the convenience of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design.

[0044] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of this application shall have the usual meanings understood by those of ordinary skill in the art to which this application belongs. The words used in the description of this application to indicate orientation are only used to indicate relative directions or positional relationships. When the absolute position of the described object changes, its relative positional relationship may also change accordingly. The word "include" used in the description of this application indicates that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, but does not exclude other elements or objects.

[0045] In addition, it should be noted that, unless otherwise clearly specified and limited, the words "installation", "connection" and similar terms used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Technical personnel in the field can understand its specific meaning in this application according to the specific circumstances.

[0046] A gas turbine dry low emission combustor, such as Figure 1 As shown, it includes a combustion chamber casing 1, a flame tube 2, a venturi 3, a main combustion first-stage premixing chamber 4, a main combustion first-stage swirler 5, a main combustion second-stage premixing chamber 6, a main combustion second-stage swirler 7, a main fuel first-stage nozzle 8, a main fuel second-stage nozzle 9, a precombustion premixing chamber 10, a precombustion stage swirler 11, a precombustion premixing spray rod 12, and a nozzle assembly 13.

[0047] The flame tube 2 is arranged in the combustion chamber casing 1, and there can be multiple flame tubes 2, which are arranged circumferentially in the combustion chamber casing 1.

[0048] The outlet of the venturi tube 3 is connected to the inlet of the flame tube 2. The inlet of the venturi tube 3 is a convergent section, and the outlet is an expansion section, wherein the convergent section is conical and has a single-wall structure; the expansion section is conical and has a double-wall structure, with the inner wall and the outer wall arranged in parallel; the outer wall of the expansion section has a plurality of impact cooling holes distributed along the axial direction, and the outlet end is bent outward and connected to the inner side of the inlet of the flame tube 2; the outlet end of the inner wall of the expansion section is bent backward to form an annular cooling flow gap with the inner side of the inlet of the flame tube 2, and the outer wall of the outlet end of the inner wall of the expansion section can be designed to have an annular reinforcement protrusion, such as Figure 2 The air entering the combustion chamber casing 1 can pass through the impact cooling holes on the outer wall of the expansion section of the venturi tube 3, enter between the inner wall and the outer wall of the expansion section, and impact cool the inner wall, and then flow out through the annular cooling flow gap to form a cooling air film on the inner side of the inlet of the flame tube 2, thereby ensuring that the venturi tube 3 and its flame tube 2 are not ablated.

[0049] The main combustion secondary premixing chamber 6 is arranged in the combustion chamber casing 1, and the outlet is connected to the inlet of the venturi 3.

[0050] The main fuel secondary swirler 7 is arranged in the main fuel secondary premixing chamber 6 , and can be arranged at the inlet of the main fuel secondary premixing chamber 6 .

[0051] The primary premixing chamber 4 of the main combustion is connected to the inner side of the secondary premixing chamber 6 of the main combustion, and is arranged parallel to the secondary premixing chamber 6 of the main combustion in the radial direction.

[0052] The primary cyclone 5 of the main fuel is arranged in the primary premixing chamber 4 of the main fuel, and can be arranged at the inlet of the primary cyclone 6 of the main fuel, and adopts a weak swirl design.

[0053] The primary fuel nozzle 8 is arranged at the inlet of the primary fuel premixing chamber 4 .

[0054] The main fuel secondary nozzle 9 is arranged at the inlet of the main fuel secondary premixing chamber 6, and can be connected to the main fuel primary nozzle 8 on the same pipeline, passing through the outside of the combustion chamber casing 1, and connected to an external fuel source.

[0055] The main fuel first-stage nozzle 8 and the main fuel second-stage nozzle 9 can spray fuel into the main fuel first-stage premixing chamber 4 and the main fuel second-stage premixing chamber 6, and mix with the air entering the main fuel first-stage premixing chamber 4 and the main fuel second-stage premixing chamber 6 from the combustion chamber casing 1 under the action of the main fuel first-stage swirler 5 and the main fuel second-stage swirler 7. The fuel can be evenly mixed and rotated to flow into the venturi 3, and then flow into the flame tube 2 for premixed combustion, which can have lower emissions. In addition, the main fuel first-stage swirler 5 adopts a weak swirl design to ensure that the mixed gas flowing out of the main fuel second-stage swirler 7 does not interfere with each other.

[0056] The pre-combustion premixing chamber 10 is connected to the inner side of the main combustion first premixing chamber 4, and is arranged radially parallel to the main combustion first premixing chamber 4 and the main combustion second premixing chamber 6, and the inlet can extend to the inlet of the combustion chamber casing 1.

[0057] The nozzle assembly 13 is arranged in the pre-combustion premixing chamber 10, and the front end can be connected to the inlet of the combustion chamber casing 1 through a support plate, and the rear end can be axially located at the inlet of the main combustion first-stage premixing chamber 4 and the main combustion second-stage premixing chamber 6, and a central duty spray hole A and a plurality of circumferentially distributed fuel diffusion spray holes B and purge air holes C are arranged, and each fuel diffusion spray hole B is located outside the purge air hole C and tilted outward, such as Figure 3 shown.

[0058] The central duty injection hole A is connected to the external fuel source through the duty fuel channel opened in the nozzle assembly 13 through a pipeline from the front end of the nozzle assembly 13. By injecting fuel into the pre-combustion premixing chamber 10 through the central duty injection hole A, a higher fuel concentration can be achieved locally, which is convenient for ignition, and a stable combustion can be performed in a diffusion combustion mode.

[0059] Each fuel diffusion nozzle B is connected to the fuel connection channel opened in the front end of the nozzle assembly 13 through the annular fuel channel opened in the rear end of the nozzle assembly 13, and is connected to the external fuel source through the pipeline from the front end of the nozzle assembly 13. Fuel is sprayed into the pre-combustion premixing chamber 10 through each fuel diffusion nozzle B, and can be mixed with the air entering the combustion premixing chamber 10 from the combustion chamber casing 1, and enters the reflow zone in the flame tube 2 through the venturi 3 in the mode of diffusion combustion.

[0060] Each purging air hole C is connected to the air communication channel opened in the front end of the nozzle assembly 13 through the annular air channel opened in the rear end of the nozzle assembly 13, and is connected to the air in the combustion chamber casing 1 through the opening on the side wall of the front end of the nozzle assembly 13. The air in the combustion chamber casing 1 can be ejected from the rear end of the nozzle assembly 13 through each purging air hole C, which can reduce the temperature of the rear end of the nozzle assembly 13, reduce the fuel concentration at the rear end of the nozzle assembly 13, and can blow the flame away from the rear end of the nozzle assembly 13, prevent the boundary layer from flashing back, and avoid ablation.

[0061] The pre-combustion stage swirler 11 is arranged in the pre-combustion premixing chamber 10 and is sleeved on the rear end of the nozzle assembly 13 .

[0062] There are multiple pre-combustion premixing spray rods 12, which are arranged in the pre-combustion premixing chamber 10, inserted at the front end of the nozzle assembly 13 along the circumferential direction, and connected to the duty fuel channel. Fuel is sprayed into the pre-combustion premixing chamber 10 through each pre-combustion premixing spray rod 12, and can be mixed with the air entering the combustion premixing chamber 10 from the combustion chamber casing 1, and can be rotated out through the pre-combustion stage swirler 11, and enter the flame tube 2 through the venturi tube 3 for premixed combustion.

[0063] A method for controlling a gas turbine dry low-emission combustion chamber is provided, which is used to control the gas turbine dry low-emission combustion chamber disclosed in the above-mentioned embodiment, and adopts a multi-stage staged supply and combustion form of air and fuel to broaden the low-emission operating range of the gas turbine and can ensure the stability of ignition and combustion.

[0064] When the gas turbine is started and ignited to the slow-running state, the fuel is controlled to be sprayed into the pre-combustion premixing chamber 10 through each fuel diffusion nozzle B to perform diffusion combustion, which facilitates ignition and ensures the stability of combustion.

[0065] When the gas turbine completes the small operating condition in the slow-running state, the fuel injected into the precombustion premixing chamber 10 through each fuel diffusion nozzle B is controlled to be reduced to zero, and the fuel is injected into the precombustion premixing chamber 10 through each precombustion premixing nozzle rod 12 and the central duty nozzle A to facilitate ignition and ensure combustion stability, and reduce emissions.

[0066] As the gas turbine operating condition rises to the maximum operating condition, the main fuel first-stage nozzle 8 and the main fuel second-stage nozzle 9 are controlled in turn to spray fuel into the main fuel first-stage premixing chamber 4 and the main fuel second-stage premixing chamber 6 for premixed combustion. The main fuel is graded, so that the gas turbine can achieve low pollutant emission levels within a wide range of operating conditions. At the same time, the emission level and combustion stability can be easily taken into account by adjusting the proportion of fuel at each level.

[0067] The control of fuel injection can be regulated by valves arranged in the corresponding pipelines.

[0068] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the scope of protection of the present application.

Claims

1. A gas turbine dry low emission combustion chamber, characterized in that: include: Combustion chamber casing (1); The flame tube (2) is arranged in the combustion chamber casing (1); The outlet of the venturi tube (3) is connected to the inlet of the flame tube (2); A main combustion secondary premixing chamber (6) is arranged in the combustion chamber casing (1), and the outlet is connected to the inlet of the venturi tube (3); The main fuel secondary cyclone (7) is arranged in the main fuel secondary premixing chamber (6); The primary premixing chamber (4) of the main combustion is connected to the inner side of the secondary premixing chamber (6) of the main combustion, and is arranged in parallel with the secondary premixing chamber (6) of the main combustion in the radial direction; The primary combustion cyclone (5) is arranged in the primary combustion premixing chamber (4); A primary fuel nozzle (8) is arranged at the inlet of a primary fuel premixing chamber (4); The main fuel secondary nozzle (9) is arranged at the inlet of the main fuel secondary premixing chamber (6); The pre-combustion premixing chamber (10) is connected to the inner side of the primary premixing chamber (4) of the main combustion, and is arranged in parallel with the primary premixing chamber (4) of the main combustion and the secondary premixing chamber (6) of the main combustion in the radial direction; The nozzle assembly (13) is arranged in the pre-combustion premixing chamber (10), and a central duty spray hole (A) and a plurality of fuel diffusion spray holes (B) and purge air holes (C) distributed along the circumferential direction are arranged at the rear end, and each fuel diffusion spray hole (B) is located outside the purge air hole (C); A pre-combustion stage swirler (11) is arranged in the pre-combustion pre-mixing chamber (10) and is sleeved on the rear end of the nozzle assembly (13); A plurality of pre-combustion pre-mixing spray rods (12) are arranged in the pre-combustion pre-mixing chamber (10) and are inserted at the front end of the nozzle assembly (13) along the circumferential direction.

2. The gas turbine dry low emission combustion chamber according to claim 1, characterized in that: The inlet of the venturi tube (3) is a convergent section, and the outlet is an expansion section; The convergent section is conical and single-walled; The expansion section is conical and has a double-wall structure, with the inner wall and the outer wall being arranged in parallel; The outer wall of the expansion section is provided with a plurality of impingement cooling holes distributed along the axial direction, and the outlet end is bent outwardly and connected to the inner side of the inlet of the flame tube (2); The outlet end of the inner wall of the expansion section is bent backward to form an annular cooling flow gap with the inner side of the inlet of the flame tube (2), and the outer wall of the outlet end of the inner wall of the expansion section is provided with an annular reinforcement protrusion.

3. The gas turbine dry low emission combustion chamber according to claim 2, characterized in that: The main combustion first-stage cyclone (5) adopts a weak cyclone design.

4. The gas turbine dry low emission combustion chamber according to claim 3, characterized in that: The main fuel secondary nozzle (9) and the main fuel primary nozzle (8) are connected to the same pipeline, pass through the outside of the combustion chamber casing (1), and are connected to an external fuel source.

5. The gas turbine dry low emission combustion chamber according to claim 4, characterized in that: The front end of the nozzle assembly (13) can be connected to the inlet of the combustion chamber casing (1) through a support plate.

6. The gas turbine dry low emission combustion chamber according to claim 5, characterized in that: Each fuel diffusion nozzle (B) is inclined outward.

7. The gas turbine dry low emission combustion chamber according to claim 6, characterized in that: The central duty spray hole (A) is connected to an external fuel source through a duty fuel channel opened in the nozzle assembly (13) and a pipeline from the front end of the nozzle assembly (13).

8. The gas turbine dry low emission combustion chamber according to claim 7, characterized in that: Each fuel diffusion nozzle hole (B) is connected to a fuel connection channel opened in the front end of the nozzle assembly (13) through an annular fuel channel opened in the rear end of the nozzle assembly (13), and is connected to an external fuel source through a pipeline from the front end of the nozzle assembly (13).

9. The gas turbine dry low emission combustor according to claim 8, characterized in that: Each cleaning air hole (C) is connected to an air communication channel opened in the front end of the nozzle assembly (13) through an annular air channel opened in the rear end of the nozzle assembly (13), and is connected to the air in the combustion chamber casing (1) through an opening on the front end side wall of the nozzle assembly (13).

10. A method for controlling a gas turbine dry low emission combustion chamber, for controlling the gas turbine dry low emission combustion chamber according to claim 1, characterized in that: include: When the gas turbine is started and ignited to an idling state, fuel is sprayed into a pre-combustion pre-mixing chamber (10) through each fuel diffusion nozzle (B) to perform diffusion combustion; When the gas turbine is in a slow-running state and a small operating condition is completed, the fuel injected into the pre-combustion pre-mixing chamber (10) through each fuel diffusion nozzle (B) is controlled to be reduced to zero, and the fuel injected into the pre-combustion pre-mixing chamber (10) through each pre-combustion pre-mixing nozzle rod (12) and the central duty nozzle (A) is controlled; As the gas turbine operating condition rises to a maximum operating condition, the main fuel first-stage nozzle (8) and the main fuel second-stage nozzle (9) are sequentially controlled to spray fuel into the main fuel first-stage premixing chamber (4) and the main fuel second-stage premixing chamber (6) to perform premixed combustion.

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