Steam cycle, and method for operating a steam cycle

Patent metadata

Field	Value
Publication number	US-10167742-B2
Application number	US-201515306545-A
Country	US
Kind code	B2
Filing date	Apr 16, 2015
Priority date	May 6, 2014
Publication date	Jan 1, 2019
Grant date	Jan 1, 2019

Abstract

A steam cycle for a power station, and to a method for operating, in particular for starting, a steam cycle. The steam cycle has a high-pressure turbine, a condenser and a steam generator. The steam generator is connected to the high-pressure turbine via a first line. Live steam quick-closing valves and live steam regulating valves for supplying the high-pressure turbine are arranged in the direction of the steam flow between the steam generator and the high-pressure turbine. A starting line is arranged downstream of the high-pressure turbine in the direction of the steam flow, the starting line connecting a waste steam region downstream of the high-pressure turbine with the condenser. At least one regulator regulates a closing of a starting valve for sealing the starting line, and an opening of the live steam valve, depending on the rotational speed, a temperature and load state of the high-pressure turbine.

First claim

The invention claimed is:

1. A steam circuit for a power plant, comprising:
a high-pressure turbine, a condenser and a steam generator,
wherein the steam generator is connected to the high-pressure turbine via a first line,
wherein, in the flow direction of the steam, at least one live steam valve is arranged between the steam generator and the high-pressure turbine, and
wherein, in the flow direction of the steam, a start-up line is arranged downstream of the high-pressure turbine and connects an exhaust steam region downstream of the high-pressure turbine to the condenser,
at least one controller which, in dependence on operating parameters of the high-pressure turbine, controls closing of a start-up valve for closing the start-up line and opening of the at least one live steam valve,
wherein opening of the start-up valve is controllable, at least stepwise, between the positions “fully open” and “fully closed”, and a setpoint pressure value of the controller is raised in dependence on the opening of the start-up valve.

2. The steam circuit as claimed in claim 1 ,
wherein the operating parameters of the high-pressure turbine are a rotational speed, a temperature, a pressure and/or a load state of the high-pressure turbine.

3. The steam circuit as claimed in claim 1 ,
wherein the controllers are integrated into a common module.

4. The steam circuit as claimed in claim 1 , further comprising:
a reheater provided between the high-pressure turbine and a further turbine stage.

5. The steam circuit as claimed in claim 4 ,
wherein the start-up line branches off between the high-pressure turbine and the reheater, and opens into the condenser.

6. The steam circuit as claimed in claim 4 , further comprising:
a check device in a line section between the high-pressure turbine and the reheater, which prevents the steam flowing back toward the high-pressure turbine.

7. The steam circuit as claimed in claim 1 , further comprising:
another line arranged parallel, at least in sections, to the start-up line and also connects the high-pressure turbine to the condenser.

8. A method for operating, a steam circuit having a high-pressure turbine, a condenser and a steam generator, the method comprising:
beginning a start-up procedure of the steam turbine,
accelerating the steam turbine by opening live steam valves,
opening a start-up line and activating a pressure-limiting controller,
accelerating the steam turbine to its rated speed,
operating the steam turbine in no-load operation and synchronization with the grid,
increasing the output of the steam turbine, until a steam mass flow through the high-pressure turbine reaches a threshold value,
beginning the procedure of closing the start-up line by closing a start-up valve,
from a defined position of the start-up valve, controlled raising of the pressure upstream of the inlet into the high-pressure turbine by means of the pressure-limiting controller, and
ending the procedure of closing the start-up line by fully closing the start-up valve and transition of the steam turbine into output operation.

9. The method as claimed in claim 8 ,
wherein the pressure upstream of the inlet into the high-pressure turbine is raised in a time-delayed and continuous manner, at a predefined rate.

10. The method as claimed in claim 9 ,
wherein raising the pressure upstream of the inlet into the high-pressure turbine takes place at a defined position of the start-up valve.

11. The method as claimed in claim 10 ,
wherein opening of the live steam valves is controlled via the raising of a setpoint pressure value at the pressure-limiting controller upstream of the inlet into the high-pressure turbine.

12. The steam circuit as claimed in claim 2 ,
wherein the temperature comprises the temperature in the exhaust steam region.

13. The steam circuit as claimed in claim 6 ,
wherein the check device comprises a check flap.

14. The steam circuit as claimed in claim 7 ,
wherein the another line comprises a line for emptying the high pressure turbine.

Assignees

• Siemens Ag

Inventors

• Leu Bernd
• Ophey Martin
• Rothe Klaus
• Veltmann David
• Brune Kai
• Heue Matthias
• Pötter Rudolf
• Schütz Michael

Classifications

• F01K13/02 Primary

  Controlling, e.g. stopping or starting · CPC title

• F01K9/04

  with dump valves to by-pass stages · CPC title

• F01K7/22 Primary

  the turbines having inter-stage steam heating · CPC title