Power plants – Combustion products used as motive fluid – With addition of steam and/or water
Reexamination Certificate
2000-08-15
2001-10-23
Casaregola, Louis J. (Department: 3746)
Power plants
Combustion products used as motive fluid
With addition of steam and/or water
C060S726000
Reexamination Certificate
active
06305158
ABSTRACT:
This invention relates to combustion turbine power plant and more particularly, to method of operating a combustion turbine power plant so as to restore a loss of power which may occur when the combustion turbine assembly is operating at high ambient temperature or with low air density and/or to generate power which exceeds a power production of a conventional combustion turbine assembly by use of supplementary air flow.
BACKGROUND OF THE INVENTION
A combustion turbine power plant is the power plant of choice for supplying peak power. For an overwhelming majority of electric power customers (in the U.S. and abroad) power consumption reaches its peak during the summertime, the time when the power production of combustion turbines is at its lowest, due to high ambient temperature. The simplified explanation of the reduced power production is that the high ambient temperature with associated lower inlet air density, reduces mass flow through a combustion turbine assembly with a respective reduction of the power produced.
FIGS. 1
a
,
1
b
, and
1
c
present simplified heat and mass balances of a conventional General Electric Frame 7 EA combustion turbine assembly
12
operating at three ambient temperatures: 59 F (
FIG. 1
a
), 0 F (
FIG. 1
a
) 90 F (
FIG. 1
c
). The combustion turbine
12
includes a compressor
14
, an expansion turbine
16
, a combustor
18
which feeds heated combustion product gas to the expansion turbine
16
. The expansion turbine
16
is coupled to drive the compressor
14
and an electric generator
20
, which is coupled to the electric grid
17
.
Figures
1
a
-
1
c
demonstrate that the conventional General Electric combustion turbine assembly, rated at 84.5 MW at ISO conditions (59 F with 60% relative humidity), will produce maximum power of approximately 102. 5 MW when the ambient temperature is 0 F, and will drop power to approximately 76.4 MW at 90 F. The significant power loss by a combustion turbine assembly during high ambient temperature periods requires a utility to purchase additional peak capacities to meet summer peak demands. Power loses for a combined cycle power plant operating at high ambient temperatures are similar to those of combustion turbine assemblies.
There are conventional methods to partially restore the loss power of combustion turbines/combined cycle plants during high ambient temperature periods: evaporative cooling and various combustion turbine inlet air chillers (mechanical or absorption type). These methods result only in partial restoration of combustion turbine power while significantly increasing capital costs, which is not always justified for an operation limited to time periods with high ambient temperatures.
Accordingly, there is a need to develop a method which will allow a combustion turbine assembly to operate at maximum power, regardless of ambient temperature.
Similar power loss problems exist in the case of a combustion turbine assembly installed at high elevation. The problem in these applications is associated with lower air density and a corresponding loss of consumption turbine power. There are currently no methods to restore power loss associated with high elevation applications.
Accordingly, a need exists to develop a method which will allow a combustion turbine assembly to maintain maximum power even when operating at high elevations.
SUMMARY OF THE INVENTION
An object of the invention is to fulfill the needs referred to above. In accordance with the principles of the present invention, these objectives are obtained by a method of operating a combustion turbine power generation system and derivatives thereof. The method provides at least one combustion turbine assembly including a compressor, an expansion turbine operatively associated with the compressor, a generator coupled with the expansion turbine; a combustor feeding the expansion turbine; flow path structure fluidly connecting an outlet of the compressor to an inlet of the combustor; a supplemental compressor structure; connection structure fluidly connecting an outlet of the supplemental compressor structure to a point upstream of the combustor, and valve structure associated with the connection structure to control flow through the connection structure. The valve structure is controlled selectively permit one of the following modes of operation: (a) a combustion turbine mode of operation wherein air compressed from the compressor moves through the flow path structure to the combustor feeding the expansion turbine such that the expansion turbine drives the generator, and (b) a power augmentation mode of operation wherein supplemental compressed air from the supplemental compressor structure is supplied through the connection structure and is directed to the combustor feeding the expansion turbine, in addition to compressed air passing through the flow path structure to the combustor feeding said expansion turbine, which increases mass flow of compressed air and gas to the expansion turbine.
The above and other objects of the present invention will become apparent during the course of the following detailed description and appended claims.
The invention may be best understood with reference to the accompanying drawings wherein illustrative embodiments are shown, and like parts are given like reference numerals.
REFERENCES:
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patent: 3151250 (1964-09-01), Carlson
patent: 4441028 (1984-04-01), Lundberg
patent: 5363642 (1994-11-01), Frutschi et al.
patent: 5379589 (1995-01-01), Cohn et al.
patent: 5495709 (1996-03-01), Frutschi
patent: 5513488 (1996-05-01), Fan
patent: 5680752 (1997-10-01), Skog
patent: 5778675 (1998-07-01), Nakhamkin
Nakhamkin Michael
Potashnik Boris
Casaregola Louis J.
Manelli Denison & Selter
Nakhamkin Michael
Stemberger Edward J.
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