U.S. patent application number 12/877427 was filed with the patent office on 2012-03-08 for combined cycle power augmentation by efficient utilization of atomizing air energy.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. Invention is credited to Joseph John, Jegadeesan Maruthamuthu, Sudhahar Rajan, Venugopala Durwasula Raju.
Application Number | 20120055166 12/877427 |
Document ID | / |
Family ID | 45595540 |
Filed Date | 2012-03-08 |
United States Patent
Application |
20120055166 |
Kind Code |
A1 |
John; Joseph ; et
al. |
March 8, 2012 |
COMBINED CYCLE POWER AUGMENTATION BY EFFICIENT UTILIZATION OF
ATOMIZING AIR ENERGY
Abstract
A combined cycle power plant includes a gas turbine having a
first compressor, a second compressor downstream of the first
compressor, and a regenerative heat exchanger between the first and
second compressors. A steam generator is downstream of the gas
turbine and receives exhaust from the gas turbine. A closed loop
cooling system through the regenerative heat exchanger and the
steam generator transfers heat from the regenerative heat exchanger
to the steam generator. A method for operating a combined cycle
power plant includes compressing a working fluid in a compressor
and cooling the compressed working fluid with a regenerative heat
exchanger so as to create a cooled compressed working fluid. The
method further includes transferring heat from the regenerative
heat exchanger to a steam generator.
Inventors: |
John; Joseph; (Chennai,
IN) ; Maruthamuthu; Jegadeesan; (Dindigul, IN)
; Rajan; Sudhahar; (Tirunelveli, IN) ; Raju;
Venugopala Durwasula; (Kadapa, IN) |
Assignee: |
GENERAL ELECTRIC COMPANY
Schenectady
NY
|
Family ID: |
45595540 |
Appl. No.: |
12/877427 |
Filed: |
September 8, 2010 |
Current U.S.
Class: |
60/772 ;
60/39.182 |
Current CPC
Class: |
F01K 23/10 20130101;
F02C 7/2365 20130101; Y02P 80/15 20151101; F02C 6/003 20130101;
Y02E 20/16 20130101; Y02P 80/154 20151101; F02C 7/10 20130101 |
Class at
Publication: |
60/772 ;
60/39.182 |
International
Class: |
F02C 6/00 20060101
F02C006/00 |
Claims
1. A combined cycle power plant comprising: a. a gas turbine,
wherein the gas turbine includes a first compressor, at least one
combustor downstream of the first compressor, and a turbine
downstream of the combustor; b. a second compressor downstream of
the first compressor; c. a regenerative heat exchanger between the
first and second compressors; d. a steam generator downstream of
the turbine, wherein the steam generator receives exhaust from the
turbine; e. a steam turbine downstream of the steam generator; f. a
condenser downstream of the steam turbine and upstream of the steam
generator; and g. a first condensate pump between the condenser and
the steam generator and in fluid communication with the
regenerative heat exchanger.
2. The combined cycle power plant as in claim 1, wherein the second
compressor is upstream of the at least one combustor.
3. The combined cycle power plant as in claim 1, wherein the first
condensate pump is in a closed loop cooling system, wherein the
closed loop cooling system transfers heat from the regenerative
heat exchanger to the steam generator.
4. The combined cycle power plant as in claim 1, further including
a second condensate pump downstream of the regenerative heat
exchanger.
5. The combined cycle power plant as in claim 4, wherein the first
condensate pump produces a first discharge pressure and the second
condensate pump produces a second discharge pressure and the second
discharge pressure of the second condensate pump is greater than
the first discharge pressure of the first condensate pump.
6. The combined cycle power plant as in claim 4, wherein the second
condensate pump is in a closed loop cooling system, wherein the
closed loop cooling system transfers heat from the regenerative
heat exchanger to the steam generator.
7. A combined cycle power plant comprising: a. a gas turbine,
wherein the gas turbine comprises a first compressor, a second
compressor downstream of the first compressor, and a regenerative
heat exchanger between the first and second compressors; b. a steam
generator downstream of the gas turbine, wherein the steam
generator receives exhaust from the gas turbine; and c. a closed
loop cooling system through the regenerative heat exchanger and the
steam generator, wherein the closed loop cooling system transfers
heat from the regenerative heat exchanger to the steam
generator.
8. The combined cycle power plant as in claim 7, further comprising
a first condensate pump in the closed loop cooling system and
upstream of the steam generator, wherein the first condensate pump
supplies coolant to the regenerative heat exchanger.
9. The combined cycle power plant as in claim 7, further comprising
a second condensate pump in the closed loop cooling system, wherein
the second condensate pump receives coolant from the regenerative
heat exchanger.
10. The combined cycle power plant as in claim 7, wherein the gas
turbine comprises at least one combustor downstream of the second
compressor.
11. The combined cycle power plant as in claim 7, wherein the gas
turbine comprises a turbine upstream of the steam generator.
12. The combined cycle power plant as in claim 7, further
comprising a steam turbine downstream of the steam generator.
13. The combined cycle power plant as in claim 12, further
comprising a condenser downstream of the steam turbine and upstream
of the steam generator.
14. A method for operating a combined cycle power plant comprising:
a. compressing a working fluid in a compressor; b. cooling the
compressed working fluid with a regenerative heat exchanger so as
to create a cooled compressed working fluid; and c. transferring
heat from the regenerative heat exchanger to a steam generator.
15. The method for operating a combined cycle power plant as in
claim 14, further comprising compressing the cooled compressed
working fluid.
16. The method for operating a combined cycle power plant as in
claim 14, further comprising flowing the cooled compressed working
fluid to at least one combustor.
17. The method for operating a combined cycle power plant as in
claim 14, further comprising atomizing a fuel with the cooled
compressed working fluid.
18. The method for operating a combined cycle power plant as in
claim 14, further comprising condensing steam from the steam
generator into condensate and pumping the condensate through a
closed loop system to the regenerative heat exchanger.
19. The method for operating a combined cycle power plant as in
claim 18, further comprising pumping the condensate from the
regenerative heat exchanger into the steam generator.
20. The method for operating a combined cycle power plant as in
claim 14, further comprising transferring at least 300 kW of power
from the regenerative heat exchanger to the steam generator.
Description
FIELD OF THE INVENTION
[0001] The present invention generally involves a power plant that
combines a conventional gas turbine with a heat recovery system to
improve the overall efficiency of the combined cycle power plant.
Specific embodiments of the present invention may include a
regenerative heat exchanger that transfers heat from the gas
turbine to the heat recovery system.
BACKGROUND OF THE INVENTION
[0002] Gas turbines are widely used in industrial and power
generation operations. A typical gas turbine includes an axial
compressor at the front, one or more combustors around the middle,
and a turbine at the rear. Ambient air enters the compressor, and
stationary vanes and rotating blades in the compressor
progressively impart kinetic energy to the working fluid (air) to
produce a compressed working fluid at a highly energized state. The
compressed working fluid exits the compressor and flows through
nozzles in the combustors where it mixes with fuel and ignites to
generate combustion gases having a high temperature, pressure, and
velocity. The combustion gases flow to the turbine where they
expand to produce work. For example, expansion of the combustion
gases in the turbine may rotate a shaft connected to a generator to
produce electricity.
[0003] The combustion gases exit the turbine, and, if released
immediately to the environment, would result in wasted energy
generated by the gas turbine that does not produce work. Therefore,
a heat recovery system is often connected downstream of the turbine
to receive the exhaust combustion gases from the turbine. The
combination of the gas turbine and heat recovery system is commonly
referred to as a combined cycle power plant. The heat recovery
system typically includes a steam generator, a steam turbine, and a
condenser. The exhaust combustion gases flow to the steam generator
where they heat water to generate steam. The steam then flows
through the steam generator where it expands to produce work. For
example, expansion of the steam in the steam turbine may rotate a
shaft connected to a generator to produce electricity. The shaft
and generator may be the same shaft and generator connected to the
gas turbine, or the gas turbine and heat recovery system may
operate using separate shafts and generators. The condenser
downstream of the steam generator condenses the steam to
condensate, and condensate pumps direct the condensate back to the
steam generator. The heat recovery system thus captures energy from
the exhaust combustion gases before they are eventually released to
the environment, thus increasing the overall efficiency of the
combined cycle power plant.
[0004] The steam generator is typically located in or upstream of a
vertical stack that allows the exhaust combustion gases to
naturally rise across tubes in the steam generator to enhance steam
generation. In some instances, a customer may limit the height of
the vertical stack, resulting in a corresponding limit in the size
of the steam generator and the amount of steam that it may produce.
In addition, the gas turbine often includes one or more heat
exchangers associated with auxiliary components, and the heat
removed by these heat exchangers is often not recaptured, thus
reducing the overall efficiency of the combined cycle power plant.
Consequently, there is a need for systems that makes more efficient
use of the heat extracted by the heat exchangers of auxiliary
components while increasing steam generation, particularly in
systems having vertical stacks of limited height.
BRIEF DESCRIPTION OF THE INVENTION
[0005] Aspects and advantages of the invention are set forth below
in the following description, or may be obvious from the
description, or may be learned through practice of the
invention.
[0006] One embodiment of the present invention is a combined cycle
power plant that includes a gas turbine having a first compressor,
at least one combustor downstream of the first compressor, a
turbine downstream of the combustor, and a second compressor
downstream of the first compressor. A regenerative heat exchanger
is between the first and second compressors, and a steam generator
is downstream of the turbine and receives exhaust from the turbine.
A steam turbine is downstream of the steam generator, and a
condenser is downstream of the steam turbine and upstream of the
steam generator. A first condensate pump is between the condenser
and the steam generator and in fluid communication with the
regenerative heat exchanger.
[0007] Another embodiment of the present invention is a combined
cycle power plant that includes a gas turbine having a first
compressor, a second compressor downstream of the first compressor,
and a regenerative heat exchanger between the first and second
compressors. A steam generator is downstream of the gas turbine and
receives exhaust from the gas turbine. A closed loop cooling system
through the regenerative heat exchanger and the steam generator
transfers heat from the regenerative heat exchanger to the steam
generator.
[0008] The present invention also includes a method for operating a
combined cycle power plant that includes compressing a working
fluid in a compressor and cooling the compressed working fluid with
a regenerative heat exchanger so as to create a cooled compressed
working fluid. The method further includes transferring heat from
the regenerative heat exchanger to a steam generator.
[0009] Those of ordinary skill in the art will better appreciate
the features and aspects of such embodiments, and others, upon
review of the specification.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] A full and enabling disclosure of the present invention,
including the best mode thereof to one skilled in the art, is set
forth more particularly in the remainder of the specification,
including reference to the accompanying figures, in which:
[0011] FIG. 1 is a simplified block diagram of a combined cycle
power plant according to one embodiment of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0012] Reference will now be made in detail to present embodiments
of the invention, one or more examples of which are illustrated in
the accompanying drawings. The detailed description uses numerical
and letter designations to refer to features in the drawings. Like
or similar designations in the drawings and description have been
used to refer to like or similar parts of the invention.
[0013] Each example is provided by way of explanation of the
invention, not limitation of the invention. In fact, it will be
apparent to those skilled in the art that modifications and
variations can be made in the present invention without departing
from the scope or spirit thereof. For instance, features
illustrated or described as part of one embodiment may be used on
another embodiment to yield a still further embodiment. Thus, it is
intended that the present invention covers such modifications and
variations as come within the scope of the appended claims and
their equivalents.
[0014] FIG. 1 shows a simplified block diagram of a combined cycle
power plant 10 according to one embodiment of the present
invention. The combined cycle power plant 10 generally includes a
gas turbine 12 connected to a heat recovery system 14 as is known
in the art. For example, as shown in FIG. 1, the gas turbine 12
includes a first compressor 16, at least one combustor 18
downstream of the first compressor 16, and a turbine 20 downstream
of the combustor 18. As used herein, the terms "upstream" and
"downstream" refer to the relative location of components in a
fluid pathway. For example, component A is upstream of component B
if a fluid flows from component A to component B. Conversely,
component B is downstream of component A if component B receives a
fluid flow from component A. The first compressor 16 produces a
compressed working fluid 22 which flows to the combustor 18. The
combustor 18 generally combines the compressed working fluid 22
with a supply of fuel 24 and/or diluent 26 and ignites the mixture
to produce combustion gases 28. The supplied fuel 24 may be any
suitable fuel used by commercial combustion engines, such as blast
furnace gas, coke oven gas, natural gas, vaporized liquefied
natural gas (LNG), propane, and any form of liquid fuel. The
diluent 26 may be any fluid suitable for diluting or cooling the
fuel, such as compressed air, steam, nitrogen, or another inert
gas. The combustion gases 28 flow to the turbine 20 where they
expand to produce work.
[0015] The heat recovery system 14 generally includes a steam
generator 30, a steam turbine 32, and a condenser 34. The steam
generator 30 is located downstream from the turbine 20, and exhaust
combustion gases 36 from the turbine 20 flow through the steam
generator 30 to produce steam 38. The steam turbine 32 is located
downstream of the steam generator 30, and the steam 38 from the
steam generator 30 expands in the steam turbine 32 to produce work.
The condenser 34 is located downstream of the steam turbine 32 and
upstream of the steam generator 30 and condenses the steam 38 from
the steam generator 30 into condensate 40 which is returned to the
steam generator 30. A first condensate pump 42 between the
condenser 34 and the steam generator 30 is in fluid communication
with the steam generator 30 to provide condensate 40 from the
condenser 34 to the steam generator 30. In addition, a second
condensate pump 44 may be present to increase the pressure of the
condensate 40 supplied to subsequent stages of the steam generator
30.
[0016] Returning to the gas turbine 12 portion of the combined
cycle power plant 10, the gas turbine 12 may further include a
second compressor 46 downstream of the first compressor 16 and
upstream of the combustor 18. The second compressor 46 receives a
portion of the compressed working fluid 48 from the first
compressor 16 and increases the pressure of the compressed working
fluid 48 from the first compressor 16. The typical increase in
pressure provided by the second compressor 46 is approximately 30
to 70%, although the actual increase in pressure is not a
limitation of the invention unless recited in the claims. The
output of the second compressor 46 may be referred to as atomizing
air 50 and is injected into the combustor 18 with the fuel 24
and/or diluent 26 to atomize the mixture to enhance the efficiency
of the combustion.
[0017] The portion of the compressed working fluid 48 supplied by
the first compressor 16 to the second compressor 46 typically has a
temperature on the order of 650 to 900.degree. F. A closed loop
cooling system between the gas turbine 12 and the heat recovery
system 14 may be used to reduce the temperature of the portion of
the compressed working fluid 48 supplied by the first compressor
16. As used herein, "a closed loop cooling system" is defined as
any cooling system in which at least some coolant in the system
flows in a repeating loop, including a system in which coolant is
added to or removed from the loop. Specifically, a regenerative
heat exchanger 52 may be located between the first and second
compressors 16, 46 to remove heat from the portion of the
compressed working fluid 48 supplied by the first compressor 16 to
the second compressor 46. As used herein, the regenerative heat
exchanger 52 includes any heat exchanger in which the heat removed
by the heat exchanger is transferred to another component for use
prior to release to the environment. The closed loop cooling system
provides a fluid communication for a coolant, such as the
condensate 40, to flow through and between the steam generator 30
and the regenerative heat exchanger 52. For example, as shown in
FIG. 1, the first condensate pump 42 may supply the coolant (e.g.,
the condensate 40) through piping to the regenerative heat
exchanger 52. As the coolant flows through the regenerative heat
exchanger 52, it removes heat from the portion of the compressed
working fluid 48 flowing through the regenerative heat exchanger 52
to the second compressor 46. For example, the regenerative heat
exchanger 52 may reduce the temperature of the compressed working
fluid 54 supplied to the second compressor 46 to less than
400.degree., 350.degree., 300.degree., or 250.degree. F., as
desired. After leaving the regenerative heat exchanger 52, at the
point indicated by reference number 56, the coolant may then flow
to the second condensate pump 44, at the point indicated by
reference number 58. The second condensate pump 44 increases the
pressure of the coolant and supplies the coolant to the steam
generator 30. In this manner, the closed loop cooling system
transfers heat from the regenerative heat exchanger 52 to the steam
generator 30, thereby increasing the overall efficiency of the
combined cycle power plant 10. In some embodiments, the amount of
heat transferred from the regenerative heat exchanger 52 to the
steam generator 30 may be capable of generating more than 200 to
650 kW of power.
[0018] One of ordinary skill in the art will readily appreciate
that the combined cycle power plant 10 described and illustrated in
FIG. 1 provides a method for operating the combined cycle power
plant 10 at an improved efficiency. Specifically, the method
includes compressing the working fluid in the first compressor 16
and cooling the compressed working fluid 48 with the regenerative
heat exchanger 52 so as to create the cooled compressed working
fluid 54. The method further includes transferring heat from the
regenerative heat exchanger 52 to the steam generator 30 so that
the heat removed by the regenerative heat exchanger 52 may be used
to generate steam 38 and perform work. The steam 38 may then be
condensed into condensate 40 and pumped through the closed loop
cooling system through the regenerative heat exchanger 52 and steam
generator 30. The cooled compressed working fluid 54 may be further
compressed and supplied to the combustors 18 to atomize the fuel 24
and/or diluent 26 with the cooled compressed working fluid 50.
Depending on the particular design needs, the method may result in
transferring more than 200 to 650 kW of power from the regenerative
the exchanger 52 to the steam generator 30.
[0019] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other and examples are intended to be within the
scope of the claims if they include structural elements that do not
differ from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the claims.
* * * * *