Gas turbine power plant with flue gas recirculation and oxygen-depleted cooling gas

• US 9,297,311 B2
• Filed: 03/21/2012
• Issued: 03/29/2016
• Est. Priority Date: 03/22/2011
• Status: Expired due to Fees

• Current Assignee: Ansaldo Energia IP UK Limited (Ansaldo Energia SPA)
• Original Assignee: Alstom Technology Ltd. (Alstom SA)
• Inventors: Hellat, Jaan, Rofka, Stefan, Hoevel, Michael, Benz, Eribert, Burdet, Andre, Sander, Frank, Guethe, Felix
• Primary Examiner(s): Wongwian, Phutthiwat
• Assistant Examiner(s): AMAR, MARC J
• Application Number:
  US13/426,043
• Publication Number:
  US 20120240590A1
• Time in Patent Office: 1,469 Days
• Field of Search: 60/395.2, 60/391.82, 415/77, 415/84, 415/83, 415/58.5
• US Class Current: 1/1
• CPC Class Codes: F01D 25/08 Cooling of machines or engines in general F01P; Heating; Heat-insulation of blade-carrying members, of blades F01D5/00
• CPC Class Codes: F01K 23/10 with exhaust fluid of one cycle heating the fluid in another cycle F01K17/025 takes precedence
• CPC Class Codes: F02C 1/08 Semi-closed cycles
• CPC Class Codes: F02C 3/30 Adding water, steam or other fluids for influencing combustion, e.g. to obtain cleaner exhaust gases F02C7/141, F02C7/30, F01D21/00, F01K21/04, F23D11/10 take precedence
• CPC Class Codes: F02C 3/34 with recycling of part of the working fluid, i.e. semi-closed cycles with combustion products in the closed part of the cycle
• CPC Class Codes: F02C 6/18 using the waste heat of gas-turbine plants outside the plants themselves, e.g. gas-turbine power heat plants using waste heat as source of energy for refrigeration plants F25B27/02; using the waste heat of a gasturbine for steam generation or in a steam cycle see F01K23/10
• CPC Class Codes: F02C 7/04 Air intakes for gas-turbine plants or jet-propulsion plants
• CPC Class Codes: F02C 7/143 before or between the compressor stages
• CPC Class Codes: F05D 2270/082 with as little NOx as possible
• CPC Class Codes: Y02E 20/16 Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT]
• CPC Class Codes: Y02E 20/32 Direct CO2 mitigation

Abstract

A method is disclosed for operating a gas turbine power plant having a gas turbine, a heat recovery steam generator and an flue gas splitter which splits flue gases into a first flue gas flow for recirculation into an inlet flow of the gas turbine and into a second flue gas flow for discharge to an environment. An oxygen-depleted gas can be used in an open cooling system for cooling hot gas parts of the gas turbine. A split compressor intake can be provided for separate feed of recirculated flue gas and fresh air into a compressor intake. Compressor blades can include a separating band which blocks intermixing of recirculated flue gas and fresh air during compression.

Claims

1. A gas turbine power plant with flue gas recirculation, comprising:

a gas turbine;

a heat recovery steam generator (HRSG);

a compressor intake through which an inlet flow will enter a compressor of the gas turbine; and

a flue gas splitter positioned downstream of the HRSG, the flue gas splitter configured to split flue gases into a first flue gas flow for recirculation into the inlet flow of the gas turbine and into a second flue gas flow for discharge to an environment,

wherein the compressor intake is split into sectors connected with a flow passage of the compressor, the sectors comprising a first sector and a second sector, a feed for fresh air leading through the first sector of the compressor intake, and a feed for the first flue gas flow leading through the second sector of the compressor intake;

an intake baffle plate configured to divide the first sector and the second sector; and

wherein the first sector and the second sector of the compressor intake are constructed as concentric annuluses radially separated by the intake baffle plate at a connection of the compressor intake to the flow passage of the compressor to define coaxial flow paths for the intake flow received by the compressor intake.

2. The gas turbine power plant as claimed in claim 1, wherein an area ratio of a connecting area of the first sector for the flow passage of the compressor to a connecting area of the second sector for the flow passage of the compressor is selected to be equal to a ratio of non-zero volumetric flows of supplied fresh air to the first flue gas flow during design conditions of the gas turbine.

3. The gas turbine power plant as claimed in claim 1, comprising:

a multiplicity of feed passages for introducing the first flue gas flow into the compressor, arranged in the compressor intake in a circumferentially distributed manner on a circle which is concentric to an axis of the gas turbine.

4. The gas turbine power plant as claimed in claim 1, comprising:

stator-blade separating band segments and/or rotor-blade separating band segments on compressor blades configured to block mixing of gases of recirculated first flue gas flow with fresh air in the compressor.

5. The gas turbine power plant as claimed in claim 1, wherein the first sector is positioned inwardly of the second sector such that the first sector is closer to a rotor of the compressor than the second sector, the first and second sectors being configured such that the feed for fresh air leading through the first sector of the compressor intake and the feed for the first flue gas flow leading through the second sector of the compressor intake form a coaxial inflow of recirculated flue gas and fresh air into the compressor.

6. The gas turbine power plant as claimed in claim 3, comprising:

stator-blade separating band segments and/or rotor-blade separating band segments on compressor blades that are configured to block mixing of gases of recirculated first flue gas flow with fresh air in the compressor.

7. The gas turbine power plant as claimed in claim 6, comprising:

a diffuser connected to an exit of the compressor such that compressed gas is passable from the compressor to the diffuser; and

a control element configured to control adding of fresh air to the recirculated first flue gas flow.

8. A compressor blade, comprising:

a single blade root configured to be connected to a rotor of a compressor or a casing of a compressor;

a single blade airfoil for a gas turbine configured with flue gas recirculation, the blade airfoil configured to connect to the blade root to extend from the blade root;

a single separating band segment attached to the blade airfoil and arranged between the blade root and a free end of the blade airfoil facing away from the blade root and forms a right angle to a longitudinal axis of the blade airfoil, the airfoil being constructed with the separating band segment such that the band segment extends radially having a first portion extending past a first side of the blade airfoil to a first free end and a second portion extending past a second side of the blade airfoil to a second free end, the second side of the blade airfoil being opposite the first side of the blade airfoil;

wherein the separating band segment is configured to be positioned adjacent to separating band segments of other blades to be attached to a compressor stage such that, when the compressor blade is in an installed position, the separating band segment is positioned adjacent to the separating band segments of the other blades to form an essentially closed annular separating band which lies perpendicular to an axis of a gas turbine that is configured to block mixing of recirculated first flue gas flow with fresh air in a compressor; and

wherein the compressor stage includes a stator blade having a second single separating band downstream from the blade root.

9. The compressor blade of claim 8, wherein the blade airfoil and the separating band are constructed as a single piece.

10. The compressor blade of claim 9, wherein the blade root is a foot.