Gas turbine power generation system

Abstract

Shaft stability is enhanced and reliability is improved. In a gas turbine power generation system of an embodiment, a pressurizing unit, a rotation control unit, a diaphragm coupling, a turbine, and a generator are disposed to line up sequentially on the same shaft. A thrust bearing is provided between the turbine and the generator. The turbine is configured such that a working medium flows from the diaphragm coupling side toward the rotation control unit side.

Claims

1. A gas turbine power generation system in which a pressurizing unit, a rotation control unit, a diaphragm coupling, a radial bearing, a turbine, and a generator are disposed to line up sequentially on a same shaft, the gas turbine power generation system comprising a thrust bearing provided between the turbine and the generator, wherein the turbine is configured such that a working medium flows from the diaphragm coupling side toward the rotation control unit side.

2. The gas turbine power generation system according to claim 1, wherein the rotation control unit has a clutch.

3. The gas turbine power generation system according to claim 2, wherein the rotation control unit further has a speed reducer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a diagram schematically illustrating a gas turbine power generation system according to an embodiment.

(2) FIG. 2 is a diagram schematically illustrating an example of a gas turbine power generation system according to a related art.

(3) FIG. 3 is a sectional view schematically illustrating an example of a diaphragm coupling 60 according to the related art.

DETAILED DESCRIPTION

(4) In a gas turbine power generation system of an embodiment, a pressurizing unit, a rotation control unit, a diaphragm coupling, a turbine, and a generator are disposed to line up sequentially on the same shaft. Between the turbine and the generator, a thrust bearing is provided. The turbine is configured such that a working medium flows from the diaphragm coupling side toward the rotation control unit side.

(5) The gas turbine power generation system according to the embodiment will be described using FIG. 1.

(6) As illustrated in FIG. 1, the gas turbine power generation system of this embodiment includes a pressurizing unit 10, a rotation control unit 20, a turbine 30, a generator 40, radial bearings 50 a diaphragm coupling 60, a thrust bearing 70, an oxygen generator 80, a combustor 81, a regenerative heat exchanger 82, a cooler 83, and a humidity separator 85. In the gas turbine power generation system of this embodiment, the respective parts are provided to constitute a semi-close cycle using a supercritical CO.sub.2 medium.

(7) Specifically, in the turbine 30, a supercritical medium (working CO.sub.2) overheated by combustion of the combustor 81 is supplied as a working medium. In the turbine 30, the working medium expands to work, thereby rotating a rotating shaft of the turbine 30 and driving the generator 40 to generate electricity.

(8) In the regenerative heat exchanger 82, a heat exchange between the medium exhausted from the turbine 30 and a medium discharged from the pressurizing unit 10 is performed. Here, by the heat exchange in the regenerative heat exchanger 82, the medium exhausted from the turbine 30 is cooled. On the other hand, by the heat exchange in the regenerative heat exchanger 82, the medium discharged from the pressurizing unit 10 is heated to be supplied to the combustor 81.

(9) The cooler 83 cools the medium subjected to the heat exchange in the regenerative heat exchanger 82 after being exhausted from the turbine 30. This causes water vapor contained in the medium discharged from the regenerative heat exchanger 82 to be condensed in the cooler 83.

(10) The humidity separator 85 is supplied with the medium discharged from the cooler 83. The humidity separator 85 separates water produced by the condensation in the cooler 83 (liquid phase water) from the supplied medium. The separated water is discharged from the humidity separator 85 to the outside. For this reason, a medium containing high-purity CO.sub.2 can be obtained in the humidity separator 85.

(11) The pressurizing unit 10 is a CO.sub.2 pump, is supplied with the medium being high-purity CO.sub.2 from the humidity separator 85, and pressurizes the supplied medium to a supercritical pressure. A part of the medium pressurized by the pressurizing unit 10 is discharged to the outside, and utilized for, for example, storage, enhanced oil recovery, and the like. Here, for example, CO.sub.2 corresponding to an amount of CO.sub.2 increased by combustion in the combustor 81 is discharged to the outside. Then, the remainder of the medium pressurized by the pressurizing unit 10 is supplied to the regenerative heat exchanger 82 to be heated therein as described above.

(12) A partial medium extracted from the middle of the regenerative heat exchanger 82 is supplied to the turbine 30 as a cooling medium (cooling CO.sub.2). The remainder of the medium passing through the regenerative heat exchanger 82 is led to the combustor 81 as described above. Further, to the combustor 81, oxygen generated from air by the oxygen generator 80 is compressed using an oxygen compressor P80 to be supplied, and a fuel such as natural gas is supplied. In the combustor 81, the fuel and the oxygen react to each other to cause the combustion.

(13) The gas turbine power generation system of this embodiment is a single-shaft type, and the pressurizing unit 10, the rotation control unit 20, the turbine 30, and the generator 40 are disposed to line up sequentially on the same shaft, similarly to a case of the related art (refer to FIG. 2). Further, the respective rotating shafts of the pressurizing unit 10, the rotation control unit 20, the turbine 30, and the generator 40 are supported to be freely rotated by using radial bearings 50. The rotation control unit 20 includes a clutch and a speed reducer, and is configured to control a rotational motion to transmit from the turbine 30 to the pressurizing unit 10.

(14) In order to absorb a thermal elongation amount due to thermal expansion and thermal contraction in an axial direction of the turbine 30, the rotating shaft of the rotation control unit 20 and the rotating shaft of the turbine 30 are coupled therebetween using a diaphragm coupling 60. The rotating shaft of the pressurizing unit 10 and the rotating shaft of the rotation control unit 20, and, the rotating shaft of the turbine 30 and the rotating shaft of the generator 40 are each coupled directly therebetween using, for example, a fastening member such as a bolt though the illustration is omitted. That is, the coupling between the rotating shaft of the rotation control unit 20 and the rotating shaft of the turbine 30 has a flexible structure, while the other couplings each have a rigid structure.

(15) Further, as a starting point of thermal elongation, the thrust bearing 70 is provided. However, in this embodiment, differently from the case of the related art, the turbine 30 is an axial flow turbine in which a working medium flows from the generator 40 side toward the rotation control unit 20 side, and the thrust bearing 70 is installed on an upstream side having a large thermal elongation amount in the turbine 30 (the right side in FIG. 1).

(16) As described above, the gas turbine power generation system of this embodiment includes a power train in which the pressurizing unit 10, the rotation control unit 20, the diaphragm coupling 60, the turbine 30, and the generator 40 are disposed sequentially on the same shaft. In this embodiment, differently from the case of the related art, between the turbine 30 and the diaphragm coupling 60, the thrust bearing 70 is not interposed. In this embodiment, the thrust bearing 70 is interposed between the turbine 30 and the generator 40. In this embodiment, this allows a length L of an overhang portion between a shaft end of the radial bearing 50 and a shaft end of the diaphragm coupling 60 to be made shorter than that in the case of the related art. As a result, in this embodiment, on the diaphragm coupling 60 side of the turbine 30 (the left side in FIG. 1), since the shaft stability can be enhanced, reliability can be improved.

(17) Incidentally, on the generator 40 side of the turbine 30 (the right side in FIG. 1), a shaft length becomes long, but the coupling between the rotating shaft of the turbine 30 and the rotating shaft of the generator 40 has the rigid structure as described above, and a Q value of a vibration mode in which the shaft end is vibrated rises slightly, which falls within a range of not affecting the shaft stability and does not have a problem.

(18) In the above-described embodiment, there is described a case where the pressurizing unit 10 installed on the same shaft as that of the turbine 30 is the CO.sub.2 pump which is supplied with the medium being high-purity CO.sub.2 from the humidity separator 85 and pressurizes the medium to a supercritical pressure, but this is not restrictive. The pressurizing unit 10 is not a pump such as the CO.sub.2 pump, and for example, in a case of being constituted as a compressor such as the above-described oxygen compressor P80, the similar effect can also be demonstrated.

(19) Further, in the above-described embodiment, there is described a case where the rotation control unit 20 includes the clutch and the speed reducer, but this is not restrictive. The rotation control unit 20 need not include the speed reducer.

(20) Several embodiments of the present invention have been explained, but these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. These novel embodiments can be embodied in a variety of other forms, and various omissions, substitutions and changes may be made without departing from the spirit of the inventions. These embodiments and their modifications are included in the scope and gist of the invention and are included in the invention described in claims and their equivalents.

REFERENCE SIGNS LIST

(21) 10 . . . pressurizing unit, 20 . . . rotation control unit, 30 . . . turbine, 40 . . . generator, 50 . . . radial bearing, 60 . . . diaphragm coupling, 61a . . . flange, 61b . . . flange, 62 . . . center tube, 63a . . . diaphragm, 63b . . . diaphragm, 70 . . . thrust bearing, 80 . . . oxygen generator, 81 . . . combustor, 82 . . . regenerative heat exchanger, 83 . . . cooler, 85 . . . humidity separator, P80 . . . oxygen compressor