JP2006242162A - Twin shaft gas turbine system and output turbine unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a twin shaft gas turbine system reduced in the whole length of the system, reduced in bearing loss to improve efficiency, and to provide an output turbine unit with the same. <P>SOLUTION: This twin shaft gas turbine system is provided with a compressor 20, a compressor driving turbine 50 for driving the compressor 20, an output turbine 70 capable of rotating at a rotating speed different from that of the compressor driving turbine 50, and a driven machine 3 structuring a unified rotor with a rotor 71 of the output turbine 71 and having a driven machine rotor 91 connected to the output turbine rotor 71 so as to work as a balance weight for taking weight balance with the output turbine rotor 71. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a two-shaft gas turbine system and a power turbine unit having a compressor drive turbine and a power turbine.

  The twin-shaft gas turbine is composed of a compressor-driven turbine (high-pressure turbine) and an output turbine (low-pressure turbine) that can rotate at different rotational speeds using combustion gas generated by burning compressed air from a compressor together with fuel in a combustor. ). The rotor of the high pressure turbine is connected to the rotor of the compressor to form a gas generator together with the compressor rotor, and the shaft power is used as the driving force of the compressor. On the other hand, the rotor of the low-pressure turbine is separately connected to the rotor of a driven machine such as a generator, a pump, or another compressor, so that the shaft power of the output turbine rotor is used as the driving force of the driven machine (Patent Document) 1 etc.).

JP 59-90723 A

  The two-shaft gas turbine may be manufactured by a manufacturer different from the driven machine, and is generally designed as a prime mover for driving the driven machine at the time of manufacture. Therefore, the gas generator and power turbine must be balanced themselves as a rotating body.

  Here, the space between the compressor-driven turbine and the output turbine is not suitable as an installation location of the bearing because it is easily affected by the heat of the high-temperature working gas. For this reason, the twin-shaft gas turbine often has a configuration in which bearings are installed avoiding the space between the compressor-driven turbine and the output turbine, and both turbines are overhanging.

  For gas generators, the compressor rotor has an appropriate weight, so weight balance can be maintained if bearings are installed before and after the compressor rotor. However, in the case of an output turbine, avoid the space between the compressor and the turbine. If a bearing is installed, a balance weight must be provided to maintain the weight balance.

  However, if a balance weight is provided in the output turbine, the total length of the two-shaft gas turbine increases accordingly. In addition, since the output turbine rotor and the driven machine rotor are each supported by a plurality of bearings so that the weight is balanced independently, when the two-shaft gas turbine system is configured by connecting them together, the entire system As a result, the number of bearings installed will increase more than necessary, and the bearing loss will increase accordingly.

  An object of the present invention is to provide a two-shaft gas turbine system and an output turbine unit that can shorten the overall length of the system, reduce bearing loss, and improve efficiency.

  To achieve the above object, the present invention provides a two-shaft gas turbine system having a compressor-driven turbine for driving a compressor and an output turbine for driving the driven machine. A driven machine rotor and an output turbine serving as a driving source thereof are integrally configured, and they are packaged as a rotating body balanced in weight alone.

  According to the present invention, the overall length of the system can be shortened, bearing loss can be reduced, and efficiency can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a conceptual diagram of a two-shaft gas turbine system according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view illustrating the entire configuration of the two-shaft gas turbine system according to an embodiment of the present invention.
1 and 2, the two-shaft gas turbine system 1 of the present embodiment includes a two-shaft gas turbine 2 and a driven machine 3. The two-shaft gas turbine 2 includes a gas generator 10 and an output turbine (low pressure turbine) 5.

  The gas generator 10 compresses the sucked air (atmosphere) and discharges the compressed air, the combustor 40 combusts the compressed air from the compressor 20 together with fuel, and generates high-temperature and high-pressure combustion gas, A compressor driving turbine (high pressure turbine) 50 that drives the compressor 20 by obtaining shaft power by the combustion gas from the combustor 40 is provided. The rotor (compressor rotor) 21 of the compressor 20 and the rotor (compressor-driven turbine rotor) 51 of the compressor-driven turbine 50 are concentrically connected to each other.

  Thereby, the gas generator 10 supplies the air compressed by the compressor 20 to the combustor 40, and the combustion gas generated by burning the compressed air together with the fuel in the combustor 40 is expanded by the compressor drive turbine 50. Thus, the shaft power obtained by the compressor drive turbine rotor 51 is used as the drive force of the compressor 20.

  On the other hand, the output turbine 70 is provided on the downstream side of the compressor drive turbine 50 and constitutes a turbine section together with the compressor drive turbine 50, and the compressor drive turbine 50 is generated by the combustion gas discharged from the compressor drive turbine 50. And an output turbine rotor 71 that can rotate at different rotational speeds independently. In some cases, the output turbine 70 is set to have a rotation speed lower than that of the compressor-driven turbine rotor 51 due to strength restrictions and a diameter larger than that of the compressor-driven turbine rotor 51 so as to ensure a required output. Therefore, the transition duct 41 may be provided between the compressor drive turbine 50 and the output turbine 70.

  Thus, when the combustion gas that has exited from the compressor-driven turbine 50 and passed through the transition duct 41 flows into the output turbine 70, turbine work is obtained by the combustion gas expanded in the output turbine 70, and the shaft power of the output turbine rotor 71 is obtained. Is used as the driving force of the driven machine 3.

  Thus, in the two-shaft gas turbine 2, the compressor driven turbine rotor 51, in other words, the gas generator 10 and the output turbine rotor 71 are separated and rotate independently of each other. It is possible to operate at different rotational speeds. Therefore, even if the rotation speed of the gas generator 10 is fixed to about the rated rotation speed, it is possible to change the rotation speed of the output turbine rotor 71 according to the driven machine to be connected, and the range of operation as a gas turbine is increased. spread.

  The structure of the compressor 20 will be described. The rotating body (compressor rotor 21) is configured by overlapping a disk wheel 23 having a plurality of moving blades 22 attached to the outer peripheral portion in the axial direction. Of the rotor blades 22 formed in a plurality of stages in this manner, the one located on the most upstream side (front side, left side in FIG. 2) is the first stage rotor blade 22a, and the most downstream side (rear side, right side in FIG. 2). The paragraph located at is the final stage rotor blade 22b.

  On the other hand, the stationary body side of the compressor 20 includes a compressor casing 24 and a stationary blade 25 fixed to the inner peripheral side of the compressor casing 24. The stationary blades 25 are located on the front side (upstream side) of the rotor blades 22 in each stage of the compressor rotor 21, and are provided in the circumferential direction in the same manner as the rotor blades 22. is doing.

  The configuration of the compressor-driven turbine 50 will be described. The rotating body (compressor-driven turbine rotor 51) includes a disk wheel 53 having a plurality of rotor blades 52 attached to the outer periphery. Although only one stage of the disk wheel 53 is shown in FIG. 2, there may be a case where the compressor-driven turbine rotor 51 is configured by overlapping a plurality of disk wheels 53 in the axial direction like the compressor rotor 21. Also in the compressor driven turbine rotor 51, among the blades 52 formed in a plurality of stages, the one located in the most upstream side (front side, left side in FIG. 2) is the first stage blade 52a, the most downstream side (rear side, In FIG. 2, the last stage blade 52b is the last stage blade 52b. However, since only one stage is shown in FIG. 2, the illustrated blade 52 is the first stage blade 52a and the last stage blade. The wing 52b is also configured.

  On the other hand, the stationary body side of the compressor drive turbine 50 includes a stationary blade 54 fixed to the inner peripheral side of the turbine casing 42. The stationary blades 54 are located on the front side (upstream side) of the rotor blades 52 in each stage of the compressor-driven turbine rotor 51 and are provided in the circumferential direction to form an annular blade row. Since the number of stages of the driving turbine 50 is one, only one stator blade cascade is shown. Although not particularly illustrated, a diaphragm having a cavity formed therein is fixed to the leading end side (inner peripheral side) of the stationary blade 54. The stationary blade 54 and the diaphragm include a stationary blade 54 and the like. An air supply system for circulating cooling air for cooling the air or sealing air for sealing the wheel space before and after the stationary blade 54 is formed. The gap between the diaphragm and the compressor driven turbine rotor 51 is sealed with packing.

  The configuration of the output turbine 70 will be described. The rotating body (output turbine rotor 71) includes a disk wheel 73 having a plurality of moving blades 72 attached to the outer peripheral portion. As in the case of the compressor driven turbine rotor 51, only one stage of the disk wheel 73 is shown in FIG. 2, but the output turbine rotor 71 may be configured by overlapping a plurality of disk wheels 73 in the axial direction. Also in the output turbine rotor 71, among the rotor blades 72 formed in a plurality of stages, the one located on the most upstream side (front side, left side in FIG. 2) is the first stage rotor blade 72a and the most downstream side (rear side, FIG. 2). The stage located in the middle right) is the final stage moving blade 72b. However, in FIG. 2, only the first stage is illustrated, so the illustrated moving blade 72 is the first stage moving blade 72a and the final stage moving blade 72b. Is also configured.

  On the other hand, the stationary body side of the output turbine 70 includes a stationary blade 74 fixed to the inner peripheral side of the turbine casing 42. The stationary blades 74 are located on the front side (upstream side) of the moving blades 72 in each stage of the output turbine rotor 71 and are provided in the circumferential direction to form an annular blade row. Since the number of paragraphs is one, only one vane blade row is shown. Further, a partition (partition plate) 43 joined to the inner peripheral side of the transition duct 41 and the stationary blade 74 between the final stage disk wheel 53 b of the compressor driven turbine rotor 51 and the first stage disk wheel 73 a of the output turbine rotor 71. , 44.

  The driven machine 3 described above is composed of load devices such as a generator, a pump, a compressor, and the like, and includes a driven machine rotor 91 that is integrated with an output turbine 6 that serves as a driving source. The driven machine rotor 91 may be configured to be fastened to the output turbine 71 via a coupling or may have a common rotating shaft, but is directly connected to the output turbine 71 without a balance weight. That is, the driven machine rotor 91 constitutes an output turbine unit 92 that is an integral rotating body together with the output turbine 71, and itself serves as a balance weight that balances the weight with the output turbine 71. In this way, the output turbine 71 and the driven machine rotor 91 (output turbine unit 92) are packaged as a rotating body that is balanced in weight only at the time of manufacture.

  The gas generator 10 described above includes the front bearing 11 provided on the front side of the compressor first stage rotor blade 22a and the front side of the first stage rotor blade 52a of the compressor drive turbine 50 (between the compressor rotor 21 and the compressor drive turbine rotor 51, Alternatively, it is rotatably supported by a rear bearing 12 provided in the vicinity of the connecting portion. On the other hand, the output turbine unit 92 (a rotating body including the output turbine rotor 71 and the driven machine rotor 91) includes a front bearing 81 provided between the final stage moving blade 72b of the output turbine 70 and the driven machine rotor 91, And it is supported only by a rear bearing 82 provided on the rear side of the driven machine rotor 91. If possible, the front bearing 81 may be provided on the front side of the first stage rotor blade 72 a of the output turbine 70. In this case, since the installation positions of the bearings change, it is necessary to adjust the weight balance so that the output turbine 81 and the driven machine rotor 91 are balanced, and to adjust the installation positions of the two bearings accordingly.

The operation and action of the two-shaft gas turbine system 1 configured as described above will be described below.
When the air sucked in by the compressor 20 is compressed, the compressed air discharged from the compressor 20 is supplied to the combustor 40 and burned together with fuel in the combustor 40. When the combustion gas generated from the combustor 40 is supplied to the compressor-driven turbine 50, turbine work is obtained by the expanding combustion gas (the shaft power of the compressor-driven turbine rotor 51 is obtained). The combustion gas leaving the compressor-driven turbine 50 further passes through the transition duct 41 and flows into the output turbine 70. The combustion gas expands to obtain turbine work (the shaft power of the output turbine rotor 71 is increased). can get). The shaft power of the compressor drive turbine rotor 51 is used as the drive force of the compressor rotor 21, and the shaft power of the output turbine rotor 71 is used as the drive force of the driven machine 3.

Here, FIG. 3 is a conceptual diagram of a general two-shaft gas turbine system, and FIG. 4 is a cross-sectional view showing an overall configuration of the general two-shaft gas turbine system. 3 and 4, the same reference numerals are given to the same parts as those in FIGS. 1 and 2 or the same role as those in FIGS.
In the comparative example shown in FIGS. 3 and 4, the output turbine rotor 71 and the driven machine rotor 91 are often manufactured by different manufacturers and are not connected at the time of manufacture. Therefore, it must be balanced as an independent rotating body.

  Since the space between the first stage rotor blade 72a of the output turbine 70 and the last stage rotor blade 52b of the compressor drive turbine 50 is a high temperature environment as a bearing installation location, the front bearing 83 of the output turbine rotor 71 is usually the last. Arranged on the rear side of the step rotor blade 72b, the output turbine rotor 71 is in a state where the rotor blade portion is overhanging. Further, the shafts constituting the gas turbine system generally need to be designed so that all the loads of the bearings 83 to 86 (and 11, 12) are positive in order to prevent unstable vibration of the shaft. is there. Therefore, in the two-shaft gas turbine system, the output turbine rotor 91 needs to provide a balance weight 100 between the front bearing 83 and the rear bearing 84 for balancing the load alone. As a result, the output turbine rotor 71 is configured as an independent rotating body with the unbalance of the weight distribution in the axial direction eliminated. On the other hand, the driven machine rotor 91 is configured as an independent rotating body supported by a front bearing 85 and a rear bearing 86 at two locations in the front and rear, and the two-shaft gas turbine 2 and the driven machine 3 are manufactured. It is connected later via a coupling 87.

  For this reason, in a general two-shaft gas turbine system, the axial length of the output turbine rotor 71 is increased by the amount that the balance weight 100 has to be installed, and the overall length of the system is increased. It was necessary. Further, the material cost of the output turbine rotor 71 increases as much as the balance weight 100 is required. Furthermore, since the output turbine rotor 71 and the driven machine rotor 91 are configured independently of each other, a plurality of bearings are required for the output turbine 71 and the driven machine rotor 91, respectively. Problems such as an increase in the amount of lubricating oil for the bearing and a reduction in efficiency due to an increase in bearing loss have also occurred. Also, labor is required for installation work such as alignment adjustment for connecting the balance weight 100 to the driven machine rotor 91.

  On the other hand, in the present embodiment, the driven machine rotor 91 itself is integrally connected to the output turbine rotor 71 so as to function as a balance weight that eliminates the weight imbalance of the output turbine rotor 71. The output turbine rotor 71 and the driven machine rotor 91 are packaged (unitized) as an output turbine unit 92. Thereby, it is not necessary to provide a balance weight in the output turbine rotor as in a general two-shaft gas turbine system. Further, since the rotating body composed of the output turbine rotor 71 and the driven machine rotor 91 is packaged, it can be supported in a balanced manner by the two bearings without causing unstable vibration.

  Thus, since the balance weight can be omitted and the number of bearings can be minimized, the system can be made compact, the installation space can be reduced, the bearing loss can be reduced, and the efficiency can be improved. Further, since the balance weight can be omitted and the number of bearings installed can be minimized, the manufacturing cost can be reduced and the installation time can be shortened.

1 is a conceptual diagram of a two-shaft gas turbine system according to an embodiment of the present invention. It is sectional drawing showing the whole structure of the twin-shaft gas turbine system which concerns on one embodiment of this invention. 1 is a conceptual diagram of a general two-shaft gas turbine system. 1 is a cross-sectional view illustrating an overall configuration of a general two-shaft gas turbine system.

Explanation of symbols

1 Two-shaft gas turbine system 3 Driven machine 20 Compressor 50 Compressor drive turbine 51 Compressor drive turbine rotor 70 Output turbine 71 Output turbine rotor 91 Driven machine rotor 92 Output turbine unit 100 Balance weight

Claims (6)

A compressor,
A compressor-driven turbine for driving the compressor;
An output turbine capable of rotating at a different rotational speed from the compressor driven turbine;
The power turbine constitutes an integral rotating body together with the output turbine, and has a driven machine rotor connected to the output turbine so as to function as a balance weight that balances the weight with the output turbine. A two-shaft gas turbine system comprising a driven machine. In a two-shaft gas turbine system having a compressor driven turbine for driving a compressor and an output turbine for driving a driven machine,
A two-shaft gas turbine system, wherein a driven machine rotor of the driven machine and an output turbine serving as a driving source of the driven machine are integrally configured and packaged as a rotating body balanced in weight alone. In a two-shaft gas turbine system having a compressor driven turbine for driving a compressor and an output turbine for driving a driven machine,
A two-shaft gas turbine system, wherein the output turbine is directly connected to a driven machine rotor of the driven machine without using a balance weight.   The two-shaft gas turbine system according to any one of claims 1 to 3, wherein the rotating body including the output turbine and the driven machine rotor is supported only by bearings installed at two positions before and after the driven machine rotor. A two-shaft gas turbine system.   The twin-shaft gas turbine system according to any one of claims 1 to 3, wherein the rotating body including the output turbine and the driven machine rotor is supported by two bearings. Gas turbine system. An output turbine unit provided in a two-shaft gas turbine system having a compressor drive turbine for driving a compressor and an output turbine for driving a driven machine,
A rotor that is integrated with the output turbine, and has a driven machine rotor connected to the output turbine so as to act as a balance weight that balances the weight with the output turbine. An output turbine unit comprising a driven machine.

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