Method of operating a gas turbine power plant with exhaust gas recirculation and corresponding gas turbine power plant

Patent metadata

Field	Value
Publication number	US-9856792-B2
Application number	US-201414467500-A
Country	US
Kind code	B2
Filing date	Aug 25, 2014
Priority date	Feb 29, 2012
Publication date	Jan 2, 2018
Grant date	Jan 2, 2018

Abstract

The invention relates to a method for operating a gas turbine, in which an oxygen-reduced gas and fresh air are delivered to a compressor of the gas turbine in a radially staged manner, the fresh air being delivered via an outer sector of the inlet cross section in relation to the axis of rotation of the compressor, and the oxygen-reduced gas being delivered via an inner sector of the inlet cross section in relation to the axis of rotation of the compressor.
The invention relates, further, to a gas turbine power plant with a gas turbine having a compressor inlet which is followed by the flow duct of the compressor and which is divided into an inner sector and an outer sector, a feed for an oxygen-reduced gas being connected to the inner sector of the compressor inlet, and a fresh air feed being connected to the outer sector of the compressor inlet.

First claim

The invention claimed is:

1. A method for operating a gas turbine having a compressor with an inlet cross section, a combustion chamber and a turbine, said method comprising:
delivering an oxygen-reduced gas, which has an oxygen concentration which is lower than an average oxygen concentration of a compressor intake flow, and delivering fresh air to the compressor in a radially staged manner as part of the compressor intake flow, wherein the fresh air is delivered via an outer sector of the inlet cross section in relation to an axis of rotation of the compressor, and the oxygen-reduced gas is delivered via an inner sector of the inlet cross section in relation to the axis of rotation of the compressor, wherein the inner and outer sectors of the inlet cross section are separated by an inlet guide plate, wherein the inlet guide plate is aligned with shroud segments attached to each guide vane and moving blade of the compressor, and wherein the fresh air and the oxygen-reduced gas are delivered into the inlet cross section in a direction normal to an axis of rotation of the compressor.

2. The method as claimed in claim 1 , comprising:
dividing exhaust gases of the gas turbine into a first exhaust gas flow for recirculation into the compressor intake flow of the gas turbine and into a second exhaust gas flow for discharge into surroundings; and
delivering the first exhaust gas flow as the oxygen-reduced gas to the compressor via the inner sector of the inlet cross section.

3. The method as claimed in claim 2 , wherein a lean gas is delivered via the inner sector of the inlet cross section of the compressor.

4. The method as claimed in claim 1 , wherein at least 95% of the oxygen-reduced gas is guided into the combustion chamber of the gas turbine.

5. The method as claimed in claim 1 , wherein the fresh air is introduced into a compressor inlet without being intermixed with the oxygen-reduced gas, and at least part of the fresh air compressed in the compressor is branched off as cooling gas for cooling of hot gas parts.

6. The method as claimed in claim 1 , wherein the oxygen-reduced gas is introduced via feeds arranged upstream of a compressor inlet, so as to be distributed in a circumferential direction on a diameter of an intake duct concentrically with respect to the axis of rotation of the compressor.

7. The method as claimed in claim 1 , wherein an oxygen content of the oxygen-reduced gas compressed by the compressor and introduced into the combustion chamber is at least 3% below an average oxygen content of cooling gases branched off from the compressor.

8. The method as claimed in claim 1 , comprising:
when the gas turbine is under part load and/or is being started, guiding the fresh air into the inner sector of the compressor inlet via a regulating element.

9. A gas turbine power plant, comprising:
a compressor having a compressor inlet;
a combustion chamber following the compressor;
a turbine following the combustion chamber, wherein an inlet cross section of the compressor, which a flow duct of the compressor follows, is divided into an inner sector in relation to an axis of rotation of the compressor and an outer sector in relation to the axis of rotation of the compressor, wherein the inner sector and the outer sector of the inlet cross section are separated by an inlet guide plate, and wherein an entry point of fresh air and an oxygen-reduced gas into the compressor inlet is normal to an axis of rotation of the compressor;
a shroud segments attached to each guide vane and moving blade of the compressor is aligned with the inlet guide plate;
a feed for the oxygen-reduced gas, having an oxygen concentration lower than an average oxygen concentration of a compressor intake flow during operation of the gas turbine, wherein the feed is connected to the inner sector of the compressor inlet; and
a fresh air feed connected to the outer sector of the compressor inlet.

10. The gas turbine power plant as claimed in ciaim 9 , wherein the gas turbine power plant comprises:
an exhaust gas divider which is connected by a recirculation line to the inner sector for recirculation of a first exhaust gas flow as the oxygen-reduced gas and which is connected to an exhaust gas line for discharge of a second exhaust gas flow into surroundings.

11. The gas turbine power plant as claimed in claim 9 , wherein the inner sector and the outer sector of the compressor inlet are configured as concentric circular rings at a connection to the flow duct of the compressor.

12. The gas turbine power plant as claimed in claim 9 , wherein an area ratio of an area of connection of the outer sector to the flow duct of the compressor to an area of connection of the inner sector to the flow duct of the compressor is selected so as to be equal to a ratio of volume flows of the fresh air to a first exhaust gas flow as the oxygen-reduced gas under design conditions of the gas turbine.

13. The gas turbine power plant as claimed in claim 9 , comprising:
a regulating element by which an area ratio of an area of connection of the outer sector to the flow duct of the compressor to an area of connection of the inner sector to the flow duct of the compressor is variable to match the area ratio to changes in a ratio between the fresh air and a first exhaust gas flow as the oxygen-reduced the gas.

Assignees

• Ansaldo Energia Switzerland AG

Inventors

• Hellat Jaan
• Benz Eribert
• Graf Frank
• Wind Torsten
• Guethe Felix
• Doebbeling Klaus

Classifications

• F02C3/34

  with recycling of part of the working fluid, i.e. semi-closed cycles with combustion products in the closed part of the cycle · CPC title

• F02C7/04

  Air intakes for gas-turbine plants or jet-propulsion plants · CPC title

• F02C6/003

  Gas-turbine plants with heaters between turbine stages · CPC title

• F01D5/141 Primary

  Shape, i.e. outer, aerodynamic form (F01D5/148 - F01D5/20 take precedence; blade construction F01D5/147) · CPC title

• F02C6/08

  the gas being bled from the gas-turbine compressor · CPC title