US 7,107,774 B2 · Method and apparatus for combined cycle power plant operation

Abstract

Methods and apparatus are disclosed for starting up a combined cycle plant using a startup duct to connect an auxiliary engine to the inlet of a plurality of HRSGs or other heat recovery systems. Each HRSG is fed by a combustion turbine. Dampers are supplied to isolate each HRSG from the startup duct and its CTG. The auxiliary engine is also ported to a stack allowing simple cycle operation. Dampers are also supplied to isolate the auxiliary engine from the startup duct and from its stack. During startups, the large CTGs will be isolated and the auxiliary engine will be connected to the HRSGs and started, allowing the HRSG to pressurize. As each HRSG pressurizes, it is isolated from the startup duct and connected to its respective CTG. The CTG is then started and loaded. The auxiliary engine is turned off and isolated when the last HRSG pressurizes.

Claims28

Dependent claims

In a combined cycle power plant apparatus adapted for starting up or changing the load of the plant, said apparatus comprising in combination a plurality of combustion turbines, each having at least a turbine exhaust, and systems for recovering heat, each such system having an inlet coupled to an exhaust from a combustion turbine, the improvements comprising:

(a) an assembly for isolating said combustion turbines from said systems for recovering heat;
(b) an auxiliary engine or other hot gas generator;
(c) an auxiliary engine stack conveying exhaust from said auxiliary engine or other hot gas generator to the atmosphere;
(d) an assembly for isolating said auxiliary engine or other hot gas generator from said auxiliary engine stack;
(e) at least a startup duct system coupling exhaust from said auxiliary engine or other hot gas generator to inlets of each of said systems for recovering heat;
(f) a first damper assembly for periodically isolating said startup duct system from each of said systems for recovering heat;
and,
(g) a second damper assembly for periodically isolating said startup duct system from said auxiliary engine or other hot gas generator.

5 more elements

A method of operating a combined cycle power plant for start up, said plant comprising in combination two or more combustion turbines, each having at least a turbine exhaust, said turbines being associated with one or more systems for recovering heat, each such system having an inlet coupled to a turbine exhaust;

at least an auxiliary engine or other hot gas generator and an associated auxiliary engine stack, and at least a startup duct system coupling exhaust from said auxiliary engine or other hot gas generator to inlets of each of said systems for recovering heat, said method comprising the sequential steps of:
(a) isolating said combustion turbines from said systems for recovering heat;
(b) isolating said auxiliary engine from said auxiliary engine stack;
(c) connecting said auxiliary engine to said startup duct system;
(d) connecting the startup duct system to each system for recovering heat;
(e) starting and loading said auxiliary engine;
(f) heating said systems for recovering heat with exhaust from said auxiliary engine by passing exhaust from the auxiliary engine through said startup duct system;
(g) connecting said systems for recovering heat to their respective associated combustion turbines when a predetermined pressure or temperature or demand for electrical power is reached;
(h) starting and loading one or more of said two or more combustion turbines
(i) turning off said auxiliary engine or other hot gas generator;
(j) starting and loading any unstarted combustion turbines;
and,
(k) isolating said systems for recovering heat from said startup duct system.

10 more elements

at least an auxiliary engine or other hot gas generator and an associated auxiliary engine stack, and at least a startup duct system coupling exhaust from said auxiliary engine or other hot gas generator to inlets of each of said systems for recovering heat, said method comprising the sequential steps of:
(a) isolating all combustion turbines from said systems for recovering heat except for a lead combustion turbine;
(b) connecting the inlets of all systems for recovering heat to said startup duct system;
(c) starting and loading the lead combustion turbine;
(d) heating said systems for recovering heat with exhaust from the lead combustion turbine by passing exhaust from said lead combustion turbine through the startup duct system or directly to the systems for recovering heat;
(e) connecting remaining combustion turbines to said associated systems for recovering heat when a predetermined pressure or temperature or electrical demand is reached, except for that system for recovering heat which is directly connected to the lead combustion turbine;
(f) starting and loading remaining combustion turbines;
and,
(g) isolating the inlets of all systems for recovering heat from said startup duct system.

6 more elements

A combined cycle power plant assembly comprising in combination:

(a) at least a combustion turbine unit comprising a turbine unit exhaust;
(b) a heat recovery system connected to a combustion turbine unit, said heat recovery system comprising a heat recovery system inlet fluidically coupled to the turbine unit exhaust;
(c) a hot gas source unit capable of generating not more than a limited amount of heat in the form of hot gas exhaust, which limited amount of heat is substantially less than the amount of heat in the form of hot gas produced under normal operating conditions by the combustion turbine unit, said hot gas source unit comprising a hot gas exhaust outlet fluidically coupled both to a heat recovery system inlet and to a vent;
(d) a duct system comprising duct portions connecting the hot gas exhaust outlet to a heat recovery system inlet and directly to a vent without passing through a heat recovery system, and also duct portions connecting each turbine unit exhaust to a heat recovery system inlet;
and,
(e) a fluid flow control system associated with said duct system comprising separate fluid flow control devices in each of the following duct portions of said duct system:
(i) in each first duct portion connecting the hot gas exhaust outlet to a heat recovery system inlet;
(ii) in a second duct portion directly connecting the hot gas exhaust outlet to a vent without passing through a heat recovery system;
and (iii) in each third duct portion connecting a turbine unit exhaust to a heat recovery system inlet.

6 more elements

A method of operating a combined cycle power plant for start up, said plant comprising in combination a combustion turbine having a turbine exhaust, said turbine being associated with a system for recovering heat, such system having an inlet coupled to said turbine exhaust;

at least an auxiliary engine or other hot gas generator connected directly to an associated auxiliary engine stack without passing through said system for recovering heat, and at least a startup duct system coupling exhaust from said auxiliary engine or other hot gas generator to said inlet of said system for recovering heat, said method comprising the sequential steps of:
(a) isolating said combustion turbine from said system for recovering heat and isolating said auxiliary engine from said auxiliary engine stack;
(b) connecting said auxiliary engine to said startup duct system and connecting the startup duct system to the system for recovering heat;
(c) starting and loading said auxiliary engine;
(d) heating said system for recovering heat with exhaust from said auxiliary engine by
passing exhaust from the auxiliary engine through said startup duct system;
(e) connecting said system for recovering heat to the associated combustion turbine
when a predetermined pressure or temperature or demand for electricity is reached;
(f) starting and loading the combustion turbine;
(g) turning off said auxiliary engine or other hot gas generator;
and,
(h) isolating said system for recovering heat from said startup duct system.

9 more elements

Dependencies are inferred from the claim text.

Method and apparatus for combined cycle power plant operation

Life of this patent

Method and apparatus for combined cycle power plant operation

Life of this patent

Abstract

Claims28