JP4287341B2 - Gas turbine power generator and method for manufacturing the same - Google Patents

Description

  The present invention relates to a gas turbine power generation apparatus in which a gas turbine and a generator are combined, and a method for manufacturing the same.

  In recent years, small gas turbines called micro gas turbines have attracted attention as distributed power sources. This type of gas turbine power generator includes a turbine, a compressor, a generator, a combustor, a regenerative heat exchanger, a rectifier, an inverter, and the like. Compressed air from the compressor is heated by a regenerative heat exchanger heated by turbine exhaust and sent to a combustor where it is mixed with fuel and burned, and the high-temperature and high-pressure gas generated thereby becomes turbine energy. Then, the power generator is driven.

  In such a gas turbine, a generator rotor, a compressor rotor, and a turbine rotor are integrally coupled and arranged on the same shaft. Further, a turbine casing, a compressor casing, and a generator casing that house these rotors are integrally coupled (here, a combined body of the casings is referred to as a casing assembly).

  The arrangement of the rotors is arranged on the same shaft in the order of a power generation rotor, a compressor rotor, and a turbine rotor, and the entire rotor (rotary body) is supported by bearings provided at both ends of the generator casing. Such a configuration is a general structure of a microturbine.

  As described above, since the bearings are arranged at both shaft ends of the generator, the turbine rotor and the compressor rotor are supported in an overhang state. Patent Document 1 (Japanese Patent Application Laid-Open No. 2003-343204) discloses an inlay coupling structure in which a power generation rotor, a compressor rotor, and a turbine rotor of a micro gas turbine can be disassembled and coupled with high accuracy.

  In the overhang type rotor support structure, the assembly tolerance when assembling the turbine rotor, the compressor rotor, and the generator rotor is the residual unbalance amount. If the residual imbalance is excessive, when the rotor passes through the critical speed, the vibration of the rotor becomes large, and there are concerns about problems such as contact between the rotor and the casing and damage to the bearing. In order to solve such a problem, for example, Patent Document 2 (WO01 / 86130 A1) proposes a method for removing a residual unbalance of a combined rotor (rotating body) of a generator rotor, a compressor rotor, and a turbine rotor.

  However, in the conventional gas turbine, although the residual unbalance of the combined rotor of the generator, the compressor, and the turbine is removed, the rotor from which the residual unbalance has been removed is disassembled when incorporated into the casing or removed from the casing. There was a need. Although generators, compressors, and turbines have positioning pins, there is a risk of residual unbalance in the combined rotor after assembly due to pin and pin hole tolerance during assembly and reassembly. .

In Patent Document 3 (Japanese Patent Laid-Open No. 2002-147250), a gas turbine structure in which an integrated turbine rotor, compressor rotor, and generator rotor are assembled to a casing without being disassembled in order to solve the problem of residual imbalance. Has proposed. In this prior art, (1) radial bearings and thrust bearings that support a rotating body (turbine rotor, compressor rotor, generator rotor) are used as air bearings, and mechanical engagement of the rotating body with respect to the bearings is eliminated. ) the seal member forming a housing space of the compressor rotor by the dividable structure in the radial direction, the casing assembly (turbine casing rotating body during assembly, the compressor casing, formed by integrating a generator casing) It can be inserted into or pulled out during disassembly. Therefore, it can be assembled and removed without disassembling the rotating body.

JP 2003-343204 A WO 01 / 86130A1 JP 2002-147250 A

  As described above, Patent Document 3 proposes a gas turbine structure that can be assembled to a casing without disassembling an integrated turbine rotor, compressor rotor, and generator rotor in order to eliminate the problem of residual imbalance. However, it cannot be applied to mechanical bearings other than air bearings.

  An object of the present invention is to realize a gas turbine power generator and a method of manufacturing the same that do not increase vibration at a critical speed without increasing residual imbalance even if the rotating body has an overhang structure using a mechanical bearing. is there.

The basic configuration of the present invention is to integrally couple a rotating body formed by integrally coupling a turbine rotor, a compressor rotor, and a generator rotor, and a turbine casing, a compressor casing, and a generator casing that accommodate the rotating body. A casing assembly. The rotating body is supported by bearings provided at both ends of the generator casing. A compressor casing, wherein the end bracket closer to the compressor casing is divided respectively radially, and one is a radial direction of the bearing to the divided end bracket forming part of the generator casing It is divided and arranged.

  According to such a configuration, the rotating body and the casing assembly are assembled without disassembling the turbine rotor, the compressor rotor, and the generator rotor, even if the rotating body has an overhang structure using mechanical bearings. The rotating body can be removed from the casing. As a result, the gas turbine that maintains the residual unbalance removal state of the turbine rotor, the compressor rotor, and the generator rotor, which has been performed in advance when assembling the gas turbine power generator, and effectively suppresses the vibration at the dangerous speed. Can be provided.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a main structure of a gas turbine power generator according to an embodiment of the present invention, and shows a lower half section in a cross-sectional state. This gas turbine is of a type called a micro gas turbine.

  A rotating body 1 of a gas turbine is composed of a turbine rotor 2, a tie bolt 3 serving as a rotor shaft, a compressor rotor 4, and a generator rotor 7, and these parts are integrally coupled in series on the same shaft. ing.

  Specifically, one end of the tie bolt 3 is joined to the center of rotation of one side of the turbine rotor 2. The portion indicated by reference numeral 100 in FIG. 2 is the joint portion. FIG. 2 shows one process of manufacturing (assembling) the micro gas turbine. The end of the tie bolt 3 opposite to the joint 100 is a bolt part 3A. In the tie bolt 3, a space between the compressor rotor mounting portion 3D and the joint portion 100 is larger than that of the remaining portion, and the compressor rotor mounting portion 3D is tapered. A compressor rotor 4 having an inner taper is fitted to the tapered surface.

  In the tie bolt 3, a sleeve 6 to which a bearing collar 5 is fixed is passed and fixed to a shaft portion 3C between the compressor rotor mounting portion 3D and the generator rotor mounting portion 3B. In this embodiment, both ends of the sleeve 6 are tapered, and as shown in FIG. 2, one end 6 a is fitted to the center (taper) of one end of the compressor rotor 4, and the other end 6 b is the end of the generator rotor 7. It is fitted in the center (taper) of the part. A bearing collar 5 is fixed to a part of the outer periphery of the sleeve 6 (near the generator rotor). The bearing collar 5 includes a cylindrical portion 5a supported by a radial bearing 23b described later and a flange portion 5b supported by a thrust bearing 23b.

  The generator rotor 7 includes a cylindrical core 7C, a permanent magnet 7b serving as a rotating magnetic pole fitted around the core 7C, and a cylindrical cover 7a covering the outer periphery thereof. The compressor rotor 4, the sleeve 6, and the generator rotor 7 are fitted in series with the tie rod 3, and the nut 10 is tightened with the bolt portion 3A of the tie rod, so that these rotating elements (compressor rotor 4, sleeve 6, power generation) The machine rotor 7) is fixed coaxially. The core 7c is a cylinder made of a magnetic material, and the tie bolt 3 is passed through the center hole. The permanent magnet 7b is also a cylinder or a divided cylindrical shape, and is fitted on the outer periphery of the core 7c. The generator cover 7a prevents scattering of the permanent magnet 7a during rotation and prevents the permanent magnet 7a from slipping between the generator core 7c. With the cover 7a having an interference fitting structure, the permanent magnet 7b is pressed against the generator core 7c by a compressive stress in the radial direction. The generator 7 generates electricity by rotating in the generator stationary body.

  The turbine rotor 2 and the compressor rotor 4 are brought out of the bearings of the generator casing 19, that is, in an overhang state.

  In order to reduce the unbalanced vibration of the rotating body 1 at the critical speed when the gas turbine power generator 11 is operated, it is necessary to reduce the residual unbalance in the assembled state of the rotating body 1. The residual unbalance is reduced using a balancer. This residual imbalance can be reduced by cutting the member of the rotating body 1 to remove the mass or adding the mass.

  Next, the non-rotating member of the gas turbine power generator will be described.

  The non-rotating element is roughly divided into a turbine casing 12 that houses the turbine rotor 2, a compressor casing 16 that houses the compressor rotor 4, and a generator casing 19 that houses the generator rotor 7.

  The turbine casing 12 includes a turbine outer case 12a and a transition piece 12b, and includes a turbine nozzle 14, a spacer 15, a turbine nozzle fixing structure 40, and a labyrinth seal 42 in the casing.

  The compressor casing 16 includes an upper half portion 16c-2 and a lower half portion 16c-1 that are divided into two in the radial direction. The upper half portion 16c-2 and the lower half portion 16c-1 have horizontal dividing surfaces. The dividing surface may be a surface cut obliquely. Further, each of the upper half part and the lower half part is provided with a flange 61 projecting outward (perpendicular to the paper surface). The compressor casing 16 is formed by bolting 13 with these flanges 61.

  The compressor casing 16 has a diffuser 44 for increasing the static pressure of the compressor.

  The upper half portion 16c-2 and the lower half portion 16c-1 of the compressor casing 16 are coupled to the turbine housing 12 via bolts 16a and nuts 16b in addition to being coupled to each other via a flange 61.

  The generator casing 19 is roughly divided into a casing body 19 ', an end bracket (front bracket) 20 and an end bracket (rear bracket) 17b that close both ends of the casing body.

  Of these brackets, the rear bracket 17b closer to the compressor casing 16 is divided into two in the radial direction corresponding to the division of the compressor casing 16 (16c-1, 16c-2). 2 and the lower half portion 17b-1.

  The number of divisions between the rear bracket 17b and the compressor casing 16 is not limited to two divisions, and may be more than that. The turbine casing 12, the generator casing body 19 ', and the front bracket 20 are not divided.

  The end brackets 20 and 17b each have a bearing housing portion at the center. A radial bearing 23 c is accommodated in the front bracket 20. The rear bracket 17b accommodates a radial bearing 23a and a thrust bearing 23b, and only the bearings 23a and 23b on the rear bracket side are divided into two in the radial direction. The one radial bearing half part 23a-1 and the thrust bearing half part 23b-1 that are divided are provided in the lower half part 17b-1 of the rear bracket, and the other radial bearing half part 23a-2 (not shown) The thrust bearing half 23b-2 is provided in the upper half 17b-2 of the rear bracket in the same manner as described above.

  The upper half 16c-2 and the rear bracket upper half 17b-2 of the compressor casing divided in the radial direction are connected via a strut 17a. Similarly, the lower half 16c-1 of the compressor casing and the rear bracket are connected. The lower half 17b-1 is connected via a strut 17a.

  A generator coil 19a is fixed to the inner surface of the generator casing body 19 'via a coil outer cover (cooling jacket) 19b.

  The end brackets 17 b and 20 are connected to the generator casing main body 19 ′ via bolts 22.

  Reference numeral 24 denotes a turbine support that supports the gas turbine apparatus.

  According to this embodiment, when assembling the gas turbine power generation device 11, the rotating body 1 is incorporated into the casing assembly without being disassembled into the turbine rotor 2, the compressor rotor 4, and the generator rotor 7. Can be removed. Therefore, it is possible to provide a gas turbine that can remove residual unbalance from the rotating body 1 using a balancer, reduce residual unbalance due to assembly of the rotating body 1, and does not increase vibration at a critical speed. it can.

  FIG. 2 to FIG. 4 show an example of a method for incorporating the rotating body 1 into the casing assembly after removing the residual unbalance using a balancer.

  As shown in FIG. 2, first, the lower half portion 16b-1 of the compressor casing and the lower half portion 17b-1 of the rear bracket are integrated by the strut 17a, and the lower half portion 17b-1 of the rear bracket is integrated. The lower half part 23a-1 and the thrust bearing lower half part 23b-1 that are divided into two parts are mounted, and the lower half parts are set. In this set, the rear bracket lower half 17 b-1 and the compressor casing lower half 16 b-1 are installed via the turbine support 24.

  Next, one half disk-shaped spacer 15 divided in advance is fixed to the compressor casing lower half 16c-1 using bolts 16a and 16b.

  A turbine nozzle fixing structure 40, a compressor diffuser 44, and a labyrinth seal 42 are fixed to the spacer 15 with pins or fittings. The turbine nozzle fixing structure 40, the compressor diffuser 44, and the labyrinth seal 42 are also semi-circular and semi-cylindrical structures divided in advance, and the compressor casing lower half 16c-1 includes those semi-circular and semi-cylindrical structures. The (lower half) parts are attached to the spacer 15 and stored.

  In the next assembly process, the rotating body 1 is fitted to the lower half part. At this time, a bearing collar 5, a bearing collar 9, and a seal ring 23d are fitted to the rotating body 1. The bearing collar 5 of the rotating body 1 is set so as to have an appropriate gap between the radial bearing lower half portion 23a-1 and the thrust bearing lower half portion 23b-1 provided in the rear bracket lower half portion 17b-1. The The bearing collar 5 supports the radial load and the thrust load of the rotating body 1.

  Next, as shown in FIG. 3, the generator casing main body 19 ′, the non-divided front bracket 20, and another non-divided radial bearing 23 c attached to the bracket are inserted into the rotating body 1 in the axial direction.

  In this process, the generator coil 19a, the cooling jacket 19b, the front bracket 20, and the radial bearing 23c are assembled to the generator casing body 19 ′. A generator coil 19 a constituted by windings is fixed to a cylindrical cooling jacket 19 b, and the cooling jacket 19 b is fitted to the generator casing 19. The generator casing body 19 ′ is partially threaded and fastened to the lower half 17b-1 of the rear bracket with the bolts 18 for assembly. Similarly, the front bracket 20 is fastened to the generator casing main body 19 ′ by bolts 22 with the radial bearing 23d attached. At this time, an appropriate gap is provided between the bearing collar 9 attached to the rotating body 1 and the radial bearing 23c, and the front bracket 20 is attached.

  In FIG. 4, the compressor casing upper half 16c-2, the rear bracket upper half 17b-2, the radial bearing upper half 23a-2 and the thrust bearing half 23b-2 (not shown) are fitted to the rotating body 1. These upper half parts are connected to the lower half parts and the generator casing body 19 '.

  Specifically, the compressor casing upper half 16c-2 is placed on the compressor casing lower half 16c-1, the rear bracket upper half 17b-2 is placed on the rear bracket lower half 17b-1, and the flanges of each other 61 is fastened with the bolt 13 to assemble the compressor casing 16 and the generator casing. As described above, the compressor casing upper half 16c-2 is also connected to the generator rear bracket upper half 17b-2 via the strut 17a. The upper half portion 23a-2 of the radial bearing and the thrust bearing 23b-2 are fixed to the upper half portion 17b-2 of the rear bracket in the same manner as the lower half portion. Similarly, the spacer 15 having a semi-disc structure in which the turbine nozzle fixing structure 40, the compressor diffuser 44, and the labyrinth seal 42 are fixed is fixed to the upper half 16c-2 of the compressor casing by using bolts 16a and nuts 16b. .

  Thereafter, as shown in FIG. 1, the turbine casing 12 is connected to the compressor casing 16.

  Specifically, the turbine nozzle 14 is fixed to a turbine nozzle fixing structure 40 having a disk-like structure. The turbine nozzle 14 has a structure in which a turbine nozzle blade is provided between two ring-shaped flanges. The turbine nozzle 14 is fixed by fitting, pin fixing, bolt fastening, or the like. Note that combustion air from a combustor (not shown) is guided to the turbine nozzle 14. After the transition piece 13 is attached to the spacer 15, the turbine outer case 12a is fastened to the compressor casing 16 with bolts 16a and nuts 16b, and the assembly of the gas turbine power generator 11 is completed. Disassembly of the device is performed in these reverse steps.

  As described above, according to the structure of the present invention, when the gas turbine 11 is assembled, the casing 1 can be assembled without disassembling the rotating body 1 for each of the turbine rotor, the compressor rotor, and the generator rotor. It is possible to reduce the residual unbalance caused by the assembly of the turbine rotor 1 and to realize a gas turbine that does not increase the vibration at the critical speed.

  Another effect of the present invention will be described with reference to FIG. The present invention also has an effect of improving the efficiency of the field balance when thermal bending or displacement of the fitting portion occurs during operation. That is, when the field balance is required, only the compressor casing upper half 16c-2 is separated from the gas turbine power generator by releasing the bolts and nuts. And the mass of the balance correction position of the turbine rotor 2, the compressor rotor 4, and the generator rotor 7 at the positions indicated by the arrows F, G, and H can be removed or added. Thereby, balance correction can be easily implemented. At this time, it is still more effective to further disassemble the front bracket 20 of the generator and correct the balance of the generator 7. In FIG. 5, the spacer 15 having a semi-disc-like structure to which the turbine nozzle fixing structure 40, the compressor diffuser 44, and the labyrinth seal 42 are fixed is disassembled together with the compressor casing upper half 16d. The balance of the turbine rotor 2 and the compressor rotor 4 may be corrected by providing notches and holes in the turbine nozzle fixing structure 40 and the compressor diffuser 44 without disassembling these parts. Further, the present invention has an effect of facilitating not only the balance correction but also the inspection of the turbine 2, the compressor 4 and the bearing.

  FIG. 6 shows a mode in which the compressor rotor 4, the bearing collar 5, and the generator rotor 7 are directly fitted and fixed to the rotor shaft 3 in the rotating body 1. In the rotating body 1, one end of the intermediate shaft portion 3 c ′ between the turbine rotor 2 and the compressor rotor 4 is welded and fixed to one side of the turbine rotor 2, and the other end is fitted into the hole 4 b on one side of the compressor rotor 4. It is fixed. One end of the intermediate shaft portion 3 c between the compressor rotor 4 and the generator rotor 7 is fitted and fixed in the hole 4 c on the other surface of the compressor rotor 4. There are methods for fitting such as shrink fitting, cold fitting, and press fitting. Even the rotating body 1 formed by such fitting can be accommodated in the casing assembly without being disassembled.

  FIG. 7 shows another example of the rotating body 1. In this example, the sleeve 6 fitted to the rotor shaft 3 is integrally formed with the end plate 7d of the generator rotor. One end 6 a of the sleeve 6 is welded to the groove 4 e of the compressor rotor 4. The compressor rotor 4 is welded to a tapered portion provided on the rotor shaft 3 via a groove 4d. As a welding method, there are methods such as electron beam welding, TIG welding, and friction welding.

  The general function of the gas turbine power generator 11 will be described with reference to FIG. The turbine is a radial flow turbine and has a blade portion 2 a in the turbine rotor 2. Combustion gas introduced from a combustor (not shown) expands at the blade portion 2 a and rotates the turbine rotor 2. The compressor is a centrifugal compressor, and compresses air with a blade portion 4 a provided in the compressor rotor 4.

  The combustion gas flowing out of the combustor flows as indicated by an arrow A, is rectified by the nozzle 14, expands while passing through the turbine blade 2a, and flows out in the direction of the arrow B. The combustion gas flowing out according to the arrow B is guided to a regenerative heat exchanger (not shown).

  The compressor sucks air as indicated by an arrow C, compresses the air by the compressor blade 4 a of the compressor rotor 4, and discharges it in the direction of the arrow D. The compressed air discharged according to the arrow D is guided to the regenerative heat exchanger, preheated and guided to the combustor, and reacts with the fuel introduced into the combustor to cause combustion.

  The alternating current induced in the generator coil 19a by the rotation of the rotating body 1 is converted into a direct current by a rectifier and is converted into an alternating current by an inverter.

  The present invention can be used for a gas turbine and a power generation facility using the gas turbine.

1 is a half-sectional view of a gas turbine power generator according to an embodiment of the present invention. FIG. 6 is a half-sectional view showing one process of assembling the gas turbine power generator in the embodiment. FIG. 6 is a half-sectional view showing one process of assembling the gas turbine power generator in the embodiment. FIG. 6 is a half-sectional view showing one process of assembling the gas turbine power generator in the embodiment. FIG. 6 is a half-sectional view showing an example of maintenance of the gas turbine power generator in the embodiment. The semi-cylindrical cross-sectional view showing another aspect of the rotating body (rotor) used in the embodiment. The semi-cylindrical cross-sectional view showing another aspect of the rotating body (rotor) used in the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Turbine rotor, 2 ... Turbine rotor, 3 ... Tie bolt (rotor shaft), 4 ... Compressor rotor, 5 ... Bearing collar, 6 ... Sleeve, 7 ... Generator rotor, 11 ... Gas turbine power generator, 12 ... Turbine casing 16c-1 ... lower half of compressor casing, 16c-2 ... upper half of compressor casing, 16 ... compressor casing, 17a ... strut, 17b-1 ... lower half of rear bracket, 17b-2 ... on rear bracket Half, 19 ... Generator casing, 23a-1 ... Lower half of radial bearing, 23b-1 ... Lower half of thrust bearing, 23a-2 ... Upper half of radial bearing, 23b-2 ... Upper half of thrust bearing

Claims (6)

A rotating body formed by integrally connecting a turbine rotor, a compressor rotor, and a generator rotor; a turbine casing that accommodates the rotating body; a compressor casing; a casing assembly formed by integrally connecting the generator casing; In the gas turbine power generator in which the rotating body is supported by bearings provided at both ends of the generator casing,
Wherein the compressor casing, and the end bracket closer to the compressor casing which forms part of the generator casing, are each divided in the radial direction, and one of the bearing to the divided end brackets A gas turbine power generator, wherein the gas turbine power generator is arranged in a radial direction.   The gas turbine power generator according to claim 1, wherein the compressor casing and the end bracket that are divided in a radial direction are coupled to each other via a strut.   3. The gas turbine power generator according to claim 1, wherein the divided bearings are a radial bearing and a thrust bearing.   4. The gas turbine power generator according to claim 1, wherein the turbine rotor, the compressor rotor, and the generator rotor are coupled to each other by welding.   4. The gas turbine power generator according to claim 1, wherein the turbine rotor, the compressor rotor, and the generator rotor are coupled to each other by fitting. 5. The lower half of the compressor casing divided into two in the radial direction is integrated with the lower half of the end bracket for the generator casing divided into two, and the lower half of the end bracket is also divided into two. Setting the parts of the lower half of the bearing with the lower half attached,
A step of fitting a rotor formed by integrally connecting a turbine rotor, a compressor rotor, and a generator rotor to the lower half part; and
Inserting the main body of the generator casing, the other non-divided end bracket, and the other non-divided bearing attached to the end bracket into the rotating body in an axial direction;
The upper half part of the divided compressor casing, end bracket and bearing is fitted to the rotating body, and the upper half part is connected to the lower half part and the main body of the generator casing. And the process of
And a step of connecting a turbine case to the compressor casing.

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