Steam turbine plant and method for improving same

Patent metadata

Field	Value
Publication number	US-12372003-B2
Application number	US-202318841073-A
Country	US
Kind code	B2
Filing date	Jan 25, 2023
Priority date	Mar 17, 2022
Publication date	Jul 29, 2025
Grant date	Jul 29, 2025

Abstract

A steam turbine plant includes a steam turbine including a first gland seal provided on one side in an axial direction of a turbine rotor and a second gland seal provided on the other side in the axial direction of the turbine rotor and a gas extraction system including a gas extractor configured to extract noncondensable gas in a condenser on a downstream side of the steam turbine. Only a first discharge system for discharging a gas flowing into the first gland seal is connected to the first gland seal, and a second discharge system for discharging a gas flowing into the second gland seal is connected to the second gland seal. The first and second discharge systems are connected to the gas extraction system so as to guide a gas flowing into the first and second gland seals to the gas extractor without passing through the condenser.

First claim

The invention claimed is:

1. A steam turbine plant, comprising:
a steam turbine configured to be driven by steam supplied from a steam generation source;
a condenser configured to condense steam discharged from the steam turbine and convert the steam into water; and
a gas extraction system including a gas extractor configured to extract noncondensable gas in the condenser and connected to the condenser, wherein
the steam turbine includes
a turbine rotor that includes a first shaft portion and a second shaft portion on one side in an axial direction and the other side in the axial direction, respectively and is rotationally driven by the steam supplied from the steam generation source,
a casing that accommodates the turbine rotor with the first shaft portion and the second shaft portion penetrating, and
a first gland seal provided in a first gap between the first shaft portion and the casing and a second gland seal provided in a second gap between the second shaft portion and the casing,
only a first discharge system for discharging a gas flowing into the first gland seal is connected to the first gland seal,
only a second discharge system for discharging a gas flowing into the second gland seal is connected to the second gland seal,
the first discharge system is connected to the gas extraction system so as to guide the gas flowing into the first gland seal to the gas extractor without passing through the condenser,
the second discharge system is connected to the gas extraction system so as to guide the gas flowing into the second gland seal to the gas extractor without passing through the condenser,
wherein the gas extractor has a capacity equal to or greater than a predetermined threshold value,
the threshold value is determined based on a total amount of steam to be condensed required for the condenser, and
the threshold value is defined by an equation below:
Y= 0.75×10 (2.881+(1.401×10 −6 )X)   [Math. 1]

where X represents total amount of steam to be condensed required for the condenser, Y represents the threshold value of the capacity of the gas extractor, and units of X and Y are lb/hr.

2. The steam turbine plant according to claim 1 , wherein
the steam turbine is made up of a double-flow exhaust turbine in which steam supplied from the steam generation source is divided in two directions, rotationally drives the turbine rotor, and is discharged from two directions of one side in the axial direction and the other side in the axial direction of the turbine rotor,
the first gland seal and the second gland seal each include a first seal portion and a second seal portion disposed at an interval from an outer side toward an inner side of the steam turbine,
the first gland seal and the second gland seal are each sectioned by the first seal portion and the second seal portion and each include only one chamber that is pressure-regulatable,
the first discharge system is made up of a first discharge line having one side in the axial direction connected to the chamber of the first gland seal and the other side in the axial direction connected to the gas extraction system, and
the second discharge system is made up of a second discharge line having one side in the axial direction connected to the chamber of the second gland seal and the other side in the axial direction connected to the gas extraction system.

3. The steam turbine plant according to claim 2 , wherein
the first discharge line and the second discharge line are configured to avoid installation of a pressure regulation mechanism that regulates pressure by pressure loss of fluid.

4. The steam turbine plant according to claim 1 , wherein
the steam turbine is made up of a single-flow exhaust turbine in which steam supplied from the steam generation source flows from one side in the axial direction to the other side in the axial direction of the turbine rotor without being divided and is discharged from one direction,
the second gland seal includes a first seal portion and a second seal portion disposed at an interval from an outer side toward an inner side of the steam turbine,
the second gland seal is sectioned by the first seal portion and the second seal portion and includes only one chamber that is pressure-regulatable, and
the second discharge system is made up of a second discharge line having one side in the axial direction connected to the chamber of the second gland seal and the other side in the axial direction connected to the gas extraction system.

5. The steam turbine plant according to claim 4 , wherein
the second discharge line is configured to avoid installation of a pressure regulation mechanism that regulates pressure by pressure loss of fluid.

6. A steam turbine plant, comprising:
a steam turbine configured to be driven by steam supplied from a steam generation source;
a condenser configured to condense steam discharged from the steam turbine and convert the steam into water; and
a gas extraction system including a gas extractor configured to extract noncondensable gas in the condenser and connected to the condenser, wherein
the steam turbine includes
a turbine rotor that includes a first shaft portion and a second shaft portion on one side in an axial direction and the other side in the axial direction, respectively and is rotationally driven by the steam supplied from the steam generation source,
a casing that accommodates the turbine rotor with the first shaft portion and the second shaft portion penetrating, and
a first gland seal provided in a first gap between the first shaft portion and the casing and a second gland seal provided in a second gap between the second shaft portion and the casing,
only a first discharge system for discharging a gas flowing into the first gland seal is connected to the first gland seal,
only a second discharge system for discharging a gas flowing into the second gland seal is connected to the second gland seal,
the first discharge system is connected to the gas extraction system so as to guide the gas flowing into the first gland seal to the gas extractor without passing through the condenser,
the second discharge system is connected to the gas extraction system so as to guide the gas flowing into the second gland seal to the gas extractor without passing through the condenser,
the steam turbine is made up of a single-flow exhaust turbine in which steam supplied from the steam generation source flows from one side in the axial direction to the other side in the axial direction of the turbine rotor without being divided and is discharged from one direction,
the first gland seal includes a first seal portion, a second seal portion, and a third seal portion disposed in this order at intervals from an outer side toward an inner side of the steam turbine,
the first gland seal includes a first chamber that is sectioned by the first seal portion and the second seal portion and is pressure-regulatable and a second chamber that is sectioned by the second seal portion and the third seal portion and is pressure-regulatable,
the first discharge system is made up of a first line having one side in the axial direction connected to the first chamber and the other side in the axial direction connected to the gas extraction system and a second line having one side in the axial direction connected to the second chamber and the other side in the axial direction connected to the gas extraction system,
the second line includes a main line connected to the second chamber and the gas extraction system and a diverging line diverging from the main line and connected to a halfway position between the one side in the axial direction and the other side in the axial direction of the steam turbine,
a first on-off valve is provided on the main line of t

Assignees

• Mitsubishi Heavy Ind Ltd

Inventors

• SAKANAKA Yoshikazu

Classifications

• F05D2240/63

  Glands for admission or removal of fluids from shafts · CPC title

• F01K9/00 Primary

  Plants characterised by condensers arranged or modified to co-operate with the engines (by condensers structurally combined with engines F01K11/00; steam condensers per se F28B)(F01K23/04 takes precedence) · CPC title

• F01D11/04

  using sealing fluid, e.g. steam · CPC title

• F01D11/02

  by non-contact sealings, e.g. of labyrinth type (for sealing space between rotor blade tips and stator F01D11/08) · CPC title

• F01D11/06 Primary

  Control thereof · CPC title