System and method for operating a power plant

Patent metadata

Field	Value
Publication number	US-2017022902-A1
Application number	US-201615282635-A
Country	US
Kind code	A1
Filing date	Sep 30, 2016
Priority date	Feb 28, 2013
Publication date	Jan 26, 2017
Grant date	—

Abstract

A system including a fuel-supply system including, an auxiliary-fuel-gas compressor configured to compress a fuel for use by a gas-turbine system, an expander configured to generate power by expanding an oxidant from the gas-turbine system, and a motor/generator configured to function in a motor mode and in a generator mode, wherein the motor/generator drives fuel compression with the auxiliary fuel-gas compressor in the motor mode, and the motor/generator generates power in the generator mode as the expander uses oxidant from the gas-turbine system to drive the motor/generator

First claim

1 . A system, comprising:
an auxiliary-fuel-gas compressor configured to compress a fuel for use by a gas-turbine system; an expander configured to generate power by expanding an oxidant from the gas-turbine system; and a motor-generator configured to function in a motor mode and in a generator mode, wherein the motor-generator drives fuel compression with the auxiliary fuel-gas compressor in the motor mode, and the motor-generator generates power in the generator mode as the expander uses oxidant from the gas-turbine system to drive the motor-generator.

2 . The system of claim 1 , comprising a fuel-gas compressor-expander having both the auxiliary-fuel gas compressor and the expander as a single dual-purpose unit.

3 . The system of claim 1 , comprising a controller configured to change the motor-generator between the motor mode and the generator mode.

4 . The system of claim 3 , comprising a compressor clutch configured to engage and disengage the auxiliary-fuel-gas compressor from the motor-generator, wherein the controller controls operation of the auxiliary-fuel-gas compressor by engaging and disengaging the compressor clutch.

5 . The system of claim 4 , comprising an expander clutch configured to engage and disengage the expander from the motor-generator, wherein the controller controls operation of the expander by engaging and disengaging the expander clutch.

6 . The system of claim 3 , wherein the controller controls the release of oxidant from the gas-turbine system to the expander.

7 . The system of claim 3 , comprising a primary-fuel-gas compressor.

8 . The system of claim 7 , wherein the controller enables operation of the auxiliary-fuel gas compressor during a startup mode of the gas-turbine system.

9 . The system of claim 8 , wherein the controller enables a transition from the auxiliary-fuel-gas compressor to the primary-fuel-gas compressor during a steady-state mode of the gas-turbine system.

10 . The system of claim 9 , wherein the transition from auxiliary-fuel-gas compressor comprises a disengagement of the auxiliary-fuel-gas compressor.

11 . The system of claim 3 , wherein the controller is configured to transition the motor-generator from the motor mode to generator mode once a steady-state mode of the gas-turbine system has been reached after startup.

12 . The system of claim 11 , wherein the expander is configured to drive the motor-generator in the generator mode once the steady-state mode of the gas-turbine system has been reached after startup.

13 . The system of claim 11 , wherein the controller is configured to flare or recycle fuel gas until a pressure of the fuel gas reaches a threshold pressure during a transition from the startup to the steady-state mode.

14 . The system of claim 1 , wherein the system comprises the gas-turbine system.

15 . A method, comprising:
initiating a startup mode of a gas-turbine system; starting a motor-generator in a motor mode for the startup mode; compressing fuel for the startup mode using an auxiliary-fuel-gas compressor driven by the motor-generator in the motor mode; transitioning the gas-turbine system into a steady-state mode; driving a primary-fuel-gas compressor with the gas-turbine system to compress fuel for use in the gas-turbine system during the steady-state mode; disengaging the auxiliary-fuel-gas compressor; and transitioning the motor-generator from the motor mode to a generator mode after disengaging the auxiliary-fuel-gas compressor.

16 . The method of claim 15 , comprising:
extracting oxidant from an oxidant compressor of the gas-turbine system; and driving an expander with oxidant from the compressor.

17 . The method of claim 16 , comprising:
driving the motor-generator in the generator mode with power from the expander; and outputting power from the motor-generator in the generator mode.

18 . Tangible, non-transitory, and computer-readable medium having instructions stored thereon, wherein the instructions are configured to cause a processor to:
start up a gas-turbine system in a startup mode; utilize a motor-generator in a motor mode during the startup mode; compress fuel gas for the startup mode using an auxiliary-fuel-gas compressor driven by the motor-generator in the motor mode; transition the gas-turbine system into a steady-state mode from the startup mode; during the steady-state mode, compress fuel gas for use in the gas-turbine system using a primary-fuel-gas compressor driven using the gas-turbine system; during the steady-state mode, disengage the auxiliary-fuel-gas compressor; and transition the motor-generator from the motor mode to a generator mode after disengaging the auxiliary-fuel-gas compressor to generate auxiliary power for the gas-turbine system.

19 . The tangible, non-transitory, and computer-readable medium of claim 18 , wherein disengaging the auxiliary-fuel-gas compressor comprises disengaging a clutch that drivingly couples auxiliary-fuel-gas compressor to the motor-generator when engaged.

20 . The tangible, non-transitory, and computer-readable medium of claim 18 , wherein disengaging the auxiliary-fuel-gas compressor comprises:
opening a first valve to flow fuel gas to the primary-fuel-gas compressor; and closing a second valve to block flow of fuel gas to the auxiliary-fuel-gas compressor.

Assignees

• Gen Electric

Inventors

• Zhang Hua
• Wu Wenjie
• Hao Yongjiang

Classifications

• F02C7/236 Primary

  Fuel delivery systems comprising two or more pumps · CPC title

• F02C9/40

  specially adapted to the use of a special fuel or a plurality of fuels · CPC title

• F02C7/22

  Fuel supply systems · CPC title

• F02C3/04

  having a turbine driving a compressor (power transmission arrangements F02C7/36; control of working fluid flow F02C9/16) · CPC title

• F02C3/045

  having compressor and turbine passages in a single rotor-module (F02C3/073 takes precedence) · CPC title