KR101028474B1 - Maintenance Method of Gas Turbine Cap Assembly - Google Patents

Abstract

The present invention relates to a maintenance method of a gas turbine cap assembly, which includes an inner body and an outer body, and separates a cap assembly that is fastened to a combustor to be reused and a waste disposal component. A method of servicing a gas turbine cap assembly in which only a waste disposal component is replaced with a new component and then reassembled into the reusable component, the method comprising: separating each component of the cap assembly; Heat treating a new component replacing the component, welding and assembling the components of the inner body, nondestructively inspecting and heat treating the inner body, and washing and nondestructively inspecting the outer body. And, welding and fixing the inner body and the outer body, so that only waste disposal components are disposed. By replacing with new components and then reassembling them with reusable components, the cap assembly extends the overall life of the cap assembly and saves resources and costs.

Description

Maintenance method of gas turbine cap assembly {Maintenance Method of Gas Turbine Cap Assembly}

The present invention relates to a method of maintenance of a gas turbine cap assembly. More specifically, it relates to a maintenance method of a gas turbine cap assembly that can extend the overall life of the cap assembly and reduce resources and costs by replacing the perforated perforated plate and reassembling the remaining reusable components. .

In general, thermal power generation refers to the development of a method of converting thermal energy obtained by burning fossil fuels such as coal, oil, and gas into mechanical energy and converting it into electrical energy. It refers to the development of the method of operating the steam turbine with the steam generated by the steam generator by sending the exhaust gas to the heat recovery boiler through the exhaust duct.

In the thermal power generation method, the water is heated by heat generated by burning fuel to make steam, and then the steam is used to drive a steam turbine connected to the generator, and the power generator is driven by an internal combustion engine such as a diesel engine. System, and a power generation system using a gas turbine as a prime mover.

Turbines used in thermal power generation or combined cycle power generation are devices that generate electricity by rotating the generator by converting the thermal energy of the working medium into mechanical energy in a thermodynamic cycle using working steam or gas. In power plants, steam turbines and gas turbines are mainly used. This is used.

A steam turbine is an engine that converts the thermal energy of high pressure steam into mechanical energy, and the principle of operation is to recoil when the hot air and high pressure steam produced in a boiler is blown out and expanded from a nozzle or a fixed blade to accelerate the steam flow and hit the rotor blades. As the rotor blades rotate, the rotational force generated is ultimately converted into electrical energy.

On the other hand, gas turbines use combustion gas instead of steam and generate electricity by using combustion gas of fuel.

Gas turbine for power plant is a combination of natural gas and light oil. Compressed air is used to burn liquid fuel such as light oil. At this time, compressed air is atomized into small particles by high-speed atomizing air, which is completely used in the combustion chamber. Help burn out

In the case of natural gas combustion, on the other hand, air is supplied to the outside of the fuel nozzle to prevent flame stabilization and backfire.In addition, air is sucked into the air inlet and compressed by a compressor, and combustion gas is generated by mixing and combusting natural gas and air in the combustion chamber. Power generation is achieved by driving the furnace gas turbine.

The gas turbine is composed of air compressor, combustor and turbine. When the compressed air is compressed into the combustion chamber by the compressor, which is started by a separate power source, fuel is injected from the combustion chamber, and the high pressure combustion gas is generated. By hitting the blades of the turbine, the reaction is converted into electrical energy by using the rotational force generated by the rotation of the rotor blades.

Figure 1 is a schematic diagram showing a part of the gas turbine, Figure 2 is a cross-sectional view showing a combustor of the gas turbine, Figure 3 is a perspective view showing a cap assembly, Figure 4 is an exploded perspective view of the cap assembly, Figure 5 is an internal body A perspective view from below.

1 and 2, the gas turbine 100 is a starter (not shown) for applying a rotational force during the initial operation, a compressor 120 for sucking and compressing outside air, and fuel such as gas Combustor 130 to be combusted, the combustion gas passes through the blade 140, and the rotating shaft 150 and rotates together with the blade 140 is configured to include.

The starting device is activated when the gas turbine 100 is first started. The outside air introduced from the air suction unit 110 is sucked and compressed by the compressor 120 formed at one side of the rotating shaft 150 rotated by the starting device. A plurality of combustors 130 are arranged in the circumferential direction of the gas turbine 100. In the combustor 130, fuel such as gas is mixed and combusted together with the compressed air. When the mixed gas mixed in the combustor 130 with the compressed air is burned, the volume is rapidly increased and the volume of the combustion gas passes quickly through the blade 140. Therefore, the rotating shaft 150 is rotated and this rotational force is converted into electrical energy by a generator (not shown).

On the other hand, each combustor 130 of the gas turbine 100 includes a generally cylindrical casing 131, the casing 131 is fixed to the turbine casing 101 by a bolt or the like. One end of the casing 131 is closed by an end cover assembly 132 including a supply pipe, a manifold, a valve, and the like, which supplies fuel such as gas and air to the combustor 130. The end cover assembly 132 houses a plurality of fuel nozzles 133 (usually five) arranged circumferentially with respect to the longitudinal axis of the combustor 130.

In addition, a cylindrical sleeve 134 is mounted in the casing 131, and a liner 135 is disposed concentrically in the sleeve 134, and one end of the liner 135 has a cap assembly ( The cap assembly 200 is supported by the cap assembly 200, and the cap assembly 200 is fixed to the casing 131. The cap assembly 200 is positioned between the end cover assembly 132 and the liner 135 to block the guide of the fuel nozzle 133 and the hot combustion gas from propagating toward the nozzle.

As shown in FIG. 3 and FIG. 4, the cap assembly 200 includes an outer body 210 fixed to the combustor 130, and a porous plate 230 having a plurality of heat dissipation holes formed on the upper surface thereof for heat dissipation. do. The cap assembly 200 is provided with a plurality of slot rings 240 for guiding the injected combustion gas into the combustion chamber as a housing of the secondary fuel nozzle.

4 and 5, the cap assembly 200 includes a cylindrical inner body 220 positioned inside the outer body 210, in addition to the outer body 210. . In the state in which the fastening hole 211 formed along the circumference of the middle of the outer body 210 and the fastening hole 221 formed along the circumference of the lower end of the inner body 220 correspond to each other, the fastening pins are inserted and welded to the outer body. 210 and the inner body 220 is to be coupled.

In addition, the porous plate 230 is fixed to the upper surface of the inner body 220. The porous plate 230 is formed with a plurality of through holes into which a plurality of slot rings 240 are inserted. For example, five through holes are arranged at equal intervals in the circumferential direction, and one through the center thereof is formed. More balls may be formed.

The support part 250 positioned and fixed inside the inner body 220 has an outer ring 251 that is the same as the inner diameter of the inner body 220 and the center at a position corresponding to the center of the inner body 220. An inner ring 252 communicating with a through hole of the connector, and a connecting portion connecting the outer ring 251 and the inner ring 252 by partitioning a plurality of regions so as to support the plurality of slot rings 240 ( 253).

When the gas turbine 100 of a power plant is operated for a predetermined time, the cap assembly 200, in particular, the porous plate 230 directly exposed to the combustion gas or the like is damaged by heat or combustion gas generated by the operation of the gas turbine. In addition, thermal stress fatigue due to internal radiant heat of the combustor and crack due to combustion dynamic pressure mainly occur.

In addition, power plants are regularly maintained at regular intervals for stable power supply, that is, to prevent accidents such as sudden shutdowns.

However, the cap assembly 200 used in the combustor 130 of the gas turbine 100 has a maintenance standard for the cap assembly 200 even though only a part of the cap assembly 200 is damaged, in particular, the porous plate 230. The cap assembly 200, which has reached the end of its life, is disposed of unconditionally and unnecessarily, and thus, wastes resources unnecessarily.

In addition, the main core parts of the gas turbine field is very expensive, and since most of them are imported from foreign countries, the cost associated with the maintenance of the cap assembly has been unnecessarily increased.

Accordingly, the present invention has been made to solve the above-described problems, in the cap assembly used for the gas turbine, to distinguish the reusable components and the waste disposal components, only waste disposal components as a new component It is an object of the present invention to provide a method of repairing a gas turbine cap assembly that can be replaced and then reassembled with the reusable component, thereby extending the overall life of the cap assembly and significantly reducing the cost.

In order to achieve the above object, the present invention includes an inner body and an outer body, and after separating the cap assembly fastened to the combustor and reusing the component and the disposal disposal component, the disposal disposal A method of servicing a gas turbine cap assembly in which only components are replaced with new components and reassembled into the reusable components, the method comprising the steps of: separating each component of the cap assembly; Heat-treating a new component to be replaced; welding and assembling components of the inner body; non-destructively inspecting and heat-treating the inner body; washing and non-destructively inspecting the outer body; It characterized in that it comprises a step of fixing the inner body and the outer body by welding.

As described above, according to the present invention, by replacing only the waste disposal components with new components and reassembling them with reusable components, it is possible to extend the overall life of the cap assembly and reduce resources and costs. Will be.

Hereinafter, embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Figure 6 is a block diagram showing a maintenance method of the gas turbine cap assembly according to the present invention. As shown therein, first, the cap assembly 200 is separated from the combustor 130. In the cap assembly 200, the perforated plate 230, the slot ring, and the like are more damaged than other components by heat or combustion gas generated due to the operation of the gas turbine 100. Therefore, in the present invention, the porous plate 230, which is a waste disposal component, is separated from the cap assembly 200, and the new porous plate 230 '(see FIG. 7) can be reused in another component. Its main feature is the maintenance method to be assembled and used.

Subsequently, the fastening pins fixing the outer body 210 and the inner body 220 are removed. At this time, after removing the pin head from the outer body 210 using a grinder, the fastening pin is pushed into the fastening hole 221 of the inner body 220, and the outer body 210 and the inner body 220 are removed. Separate.

Then, the separated inner body 220 is turned upside down so that the welded portions of the inner body 220 and the porous plate 230, the slot ring 240 and the support part 250 are exposed. The welded portions of each of these components are cut and separated with a grinder. At this time, the perforated plate 230 is damaged and discarded because its life has arrived, and replaced with a new perforated plate 230 '. Reuse other components than the perforated plate.

The porous plate 230 ′ may be made of an alloy such as Hastelloy having excellent corrosion resistance, and is a member having approximately 4000 heat radiating holes formed therein. In addition, a plurality of through holes into which the plurality of slot rings 240 are inserted are formed in the porous plate 230 ′. More through holes are formed. Before welding the new porous plate 230 ′, the inner body 220 and the slot ring 240 are processed to improve the roundness of each circumferential portion to be welded and to smoothly process the surface.

Next, the processed new porous plate 230 ′ is heat-treated in a vacuum furnace, preferably heated at a temperature of approximately 1100 to 1150 ° C. for 30 minutes and slowly cooled in a vacuum furnace.

On the other hand, when separating the slot ring 240 and the support 250 from the inner body 220, there is a dimensional change according to the cutting of the welded portion. Therefore, to compensate for this, the components are welded and surface treated.

The new heat-treated porous plate 230 ′ is bonded to the upper portion of the inner body 220, and the slot ring 240 and the support part 250 are assembled to the assembly of the inner body 220 and the porous plate 230 ′. Assemble by welding.

In addition, the inner body 220 in which the perforated plate 230 ′, the slot ring 240, and the support part 250 are assembled is checked for deformation by using a separate jig (not shown) and corrected if necessary. . Moreover, each welding part can also be processed with a grinder.

Thereafter, for example, the inner body 220 in which the porous plate 230 ′, the slot ring 240, and the support part 250 are assembled by using a non-destructive test method such as a liquid penetrant test or a fluorescent penetrant test is examined. However, since the non-destructive testing method is already widely known, detailed description thereof will be omitted herein.

In addition, the inner body 220 in which the porous plate 230 ′, the slot ring 240 and the support part 250 are assembled is heat-treated in a vacuum furnace, and preferably heated at a temperature of approximately 1100 to 1150 ° C. for 30 minutes. And slowly cooled in a vacuum furnace.

As shown in Figure 7, it is preferable to weld a new spring seal (222) to the outer peripheral surface of the inner body (220).

The separated outer body 210 is washed and subjected to the non-destructive test as described above, and then the inner body 220 is fitted so that the spring seal 222 is properly abutted on the outer body 210, and these The outer body 210 and the inner body 220 are welded and fixed. At this time, the fastening holes 211 and 221 of the outer body 210 and the inner body 220 may be aligned with each other, and then the fastening pins may be inserted and welded to fix the same.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

1 is a schematic view showing part of a gas turbine.

2 is a cross-sectional view showing a combustor of a gas turbine.

3 is a perspective view of the cap assembly.

4 is an exploded perspective view of the cap assembly.

5 is a perspective view of the inner body viewed from below.

Figure 6 is a block diagram showing a maintenance method of the gas turbine cap assembly according to the present invention.

Figure 7 is a perspective view from above of the inner body after reassembly.

Claims (5)

After separating the cap assembly which includes the inner body and the outer body and the cap assembly fastened to the combustor to be reused and the waste disposal component, replace only the disposal disposal component with a new component and reuse the waste disposal component. In the maintenance method of the gas turbine cap assembly which is reassembled to the Separating each component of the cap assembly; Heat treating a new component to replace the waste disposal component; Welding and assembling the components of the inner body; Non-destructive inspection and heat treatment of the inner body, Washing and non-destructive testing the outer body; And a step of welding the inner body and the outer body to fix the gas turbine cap assembly. The method of claim 1, wherein the discarded and replaced component is a perforated plate. 3. The gas turbine cap according to claim 2, further comprising the step of performing processing to improve the roundness of each circumferential portion to be welded with other components and to smooth the surface before heat-treating the new perforated plate. Maintenance of assembly. The method of claim 1, wherein each of the heat treatment steps is performed in a vacuum furnace at a temperature of 1100 to 1150 ° C. for 30 minutes and slowly cooled in the vacuum furnace. The method of claim 1, further comprising, after the non-destructive inspection and heat treatment of the inner body, welding a new spring seal to an outer circumferential surface of the inner body.

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