U.S. patent application number 11/657661 was filed with the patent office on 2008-07-31 for power augmentation of combustion turbines with compressed air energy storage and additional expander with airflow extraction and injection thereof upstream of combustors.
Invention is credited to Michael Nakhamkin.
Application Number | 20080178601 11/657661 |
Document ID | / |
Family ID | 39645042 |
Filed Date | 2008-07-31 |
United States Patent
Application |
20080178601 |
Kind Code |
A1 |
Nakhamkin; Michael |
July 31, 2008 |
Power augmentation of combustion turbines with compressed air
energy storage and additional expander with airflow extraction and
injection thereof upstream of combustors
Abstract
A combustion turbine power generation system (10) includes a
combustion turbine assembly (11) including a main compressor (12)
constructed and arranged to receive ambient inlet air, a main
expansion turbine (14) operatively associated with the main
compressor, combustors (16) constructed and arranged to receive
compressed air from the main compressor and to feed the main
expansion turbine, and an electric generator (15) associated with
the main expansion turbine for generating electric power. A
compressed air storage (18) stores compressed air. A heat exchanger
(24) is constructed and arranged to receive a source of heat and to
receive compressed air from the storage so as to heat compressed
air received from the storage. An air expander (28) is associated
with the heat exchanger and is constructed and arranged to expand
the heated compressed air for producing additional electric power.
Airflow, extracted from the expander, is injected into the
combustion turbine assembly upstream of the combustors for
combustion turbine assembly power augmentation.
Inventors: |
Nakhamkin; Michael; (Basking
Ridge, NJ) |
Correspondence
Address: |
MANELLI DENISON & SELTER
2000 M STREET NW SUITE 700
WASHINGTON
DC
20036-3307
US
|
Family ID: |
39645042 |
Appl. No.: |
11/657661 |
Filed: |
January 25, 2007 |
Current U.S.
Class: |
60/773 ;
60/727 |
Current CPC
Class: |
F02C 6/18 20130101; Y02E
60/15 20130101; Y02E 60/16 20130101; F02C 6/16 20130101; Y02E 20/16
20130101; F02C 7/10 20130101 |
Class at
Publication: |
60/773 ;
60/727 |
International
Class: |
F02C 9/00 20060101
F02C009/00 |
Claims
1. A combustion turbine power generation system comprising: a
combustion turbine assembly including a main compressor constructed
and arranged to receive ambient inlet air, a main expansion turbine
operatively associated with the main compressor, combustors
constructed and arranged to receive compressed air from the main
compressor and to feed the main expansion turbine, and an electric
generator associated with the main expansion turbine for generating
electric power, a compressed air storage storing compressed air; a
heat exchanger constructed and arranged to receive a source of heat
and to receive compressed air from the storage so as to heat
compressed air received from the storage, and an air expander
associated with the heat exchanger and constructed and arranged to
expand the heated compressed air for producing additional electric
power, wherein airflow, extracted from the expander, is injected
into the combustion turbine assembly upstream of the
combustors.
2. The system of claim 1, wherein the airflow extracted and
injected is exhaust airflow of the expander, with injection flow
parameters of the injected airflow being consistent with flow
parameters of the main compressor at an injection point.
3. The system of claim 1, wherein the airflow extracted and
injected is an airflow portion from a first stage of the expander,
with injection flow parameters of the injected airflow being
consistent with flow parameters of the main compressor at an
injection point, a remaining portion of airflow being expanded
through at least one second stage of the expander to atmospheric
pressure.
4. The system of claim 1, wherein the heat exchanger is constructed
and arranged to receive exhaust from the main expansion turbine
thereby defining the source of heat.
5. The system of claim 1, further comprising at least one auxiliary
compressor for charging the compressed air storage.
6. The system of claim 1, further including an electric generator
associated with the expander for generating the additional electric
power.
7. A combustion turbine power generation system comprising: a
combustion turbine assembly including a main compressor constructed
and arranged to receive ambient inlet air, a main expansion turbine
operatively associated with the main compressor, combustors
constructed and arranged to receive compressed air from the main
compressor and to feed the main expansion turbine, and an electric
generator associated with the main expansion turbine for generating
electric power, means for storing compressed air; means, receiving
a source of heat and receiving compressed air from the means for
storing, for heating compressed air received from the means for
storing, and means, associated with the means for heating, for
expanding the heated compressed air for producing additional
electric power, wherein airflow, extracted from the means for
expanding, is injected into the combustion turbine assembly
upstream of the combustors.
8. The system of claim 7, wherein the means for expanding is an air
expander.
9. The system of claim 8, wherein the airflow extracted from the
expander and injected into combustion turbine assembly is the
exhaust airflow of the expander with injection flow parameters of
the injected airflow being consistent with flow parameters of the
main compressor at an injection point.
10. The system of claim 8, wherein the airflow extracted from the
expander and injected into combustion turbine assembly is an
airflow portion from a first stage of the expander, with injection
flow parameters of the injected airflow being consistent with flow
parameters of the main compressor at an injection point, a
remaining portion of airflow being expanded through at least one
second stage of the expander to atmospheric pressure.
11. The system of claim 7, wherein the means for heating is a heat
exchanger constructed and arranged to receive exhaust from the main
expansion turbine thereby defining the source of heat.
12. The system of claim 7, wherein the means for storing is an
underground air storage.
13. The system of claim 12, further comprising at least one
auxiliary compressor for charging the air storage.
14. The system of claim 7, further including an electric generator
associated with the expander for generating the additional electric
power.
15. A method augmenting power of a combustion turbine assembly, the
combustion turbine assembly including a main compressor constructed
and arranged to receive ambient inlet air, a main expansion turbine
operatively associated with the main compressor, combustors
constructed and arranged to receive compressed air from the main
compressor and to feed the main expansion turbine, and an electric
generator associated with the main expansion turbine for generating
electric power, the method including: providing stored compressed
air from a compressed air storage, heating compressed air
originating from the storage, expanding the heated, compressed air
in an air expander for producing additional electric power, and
extracting airflow from the expander and injecting the extracted
airflow into the combustion turbine assembly upstream of the
combustors.
16. The method of claim 15, wherein the extracted and injected
airflow is the exhaust airflow of the expander with injection flow
parameters of the injected airflow being consistent with flow
parameters of the main compressor at an injection point.
17. The method of claim 15, wherein the extracted and injected
airflow is an airflow portion from a first stage of the expander,
with injection flow parameters of the injected airflow being
consistent with flow parameters of the main compressor at an
injection point, a remaining portion of airflow being expanded
though at least one second stage of the expander to atmospheric
pressure.
18. The method of claim 15, wherein the heating step includes using
exhaust heat from the main expansion turbine.
19. The method of claim 15, wherein the method includes producing
the additional electric power by providing an electric generator
coupled with the expander.
Description
FIELD OF THE INVENTION
[0001] This invention relates to power augmentation of combustion
turbine power systems with compressed air energy storage and
additional expander; and, more particularly, to augmenting power of
the system by expanding heated, high pressure compressed air from a
storage for producing additional expander power and extracting
airflow from the expander and injecting the extracted airflow into
the combustion turbine upstream of combustors for combustion
turbine power augmentation.
BACKGROUND OF THE INVENTION
[0002] It is well known that combustion turbines have significant
power degradation associated with increased ambient temperature or
high elevations. This loss of power is primarily associated with
the reduced mass of the combustion turbine's airflow, caused by the
reduced inlet air density.
[0003] There are a number of power augmentation technologies
targeting the recovery of the power lost by combustion turbines due
to high ambient temperatures/high elevation: [0004] The Air
Injection power augmentation technology that is based on the
injection upstream of combustors of additional airflow (humid or
dry) that is delivered by external auxiliary compressor(s); [0005]
Inlet chillers that cool the ambient air and provide a
corresponding power augmentation; [0006] Evaporative coolers, inlet
fogging and "wet compression" technologies that provide power
augmentation by a combination of the inlet air cooling and the
increased mass flow through the combustion turbine; [0007] Air
Injection power augmentation technology disclosed in my earlier
U.S. Pat. No. 5,934,063, the contents of which is incorporated by
reference herein, that is based upon air injection upstream of
combustors using a compressed air energy storage. However, the
compressed air in the storage typically has a much higher pressure
than is needed for the air injection for the power
augmentation.
[0008] Thus, there is a need to utilize the compressed air storage
high pressure to further improve the incremental power and to
improve the overall heat rate of the system.
SUMMARY OF THE INVENTION
[0009] An object of the invention is to fulfill the need referred
to above. In accordance with the principles of the present
invention, this objective is achieved by providing a combustion
turbine power generation system including a combustion turbine
assembly including a main compressor constructed and arranged to
receive ambient inlet air, a main expansion turbine operatively
associated with the main compressor, combustors constructed and
arranged to receive compressed air from the main compressor and to
feed the main expansion turbine, and an electric generator
associated with the main expansion turbine for generating electric
power. A compressed air storage stores compressed air. A heat
exchanger is constructed and arranged to receive a source of heat
and to receive compressed air from the storage so as to heat
compressed air received from the storage. An air expander is
associated with the heat exchanger and is constructed and arranged
to expand the heated compressed air for producing additional
electric power. Airflow, extracted from the expander, is injected
into the combustion turbine assembly upstream of the combustors,
with injected airflow parameters being consistent with flow
parameters of the main compressor at the injection point.
[0010] In accordance with another aspect of the invention, a method
is provided to augment power of a combustion turbine assembly. The
combustion turbine assembly includes a main compressor constructed
and arranged to receive ambient inlet air, a main expansion turbine
operatively associated with the main compressor, combustors
constructed and arranged to receive compressed air from the main
compressor and to feed the main expansion turbine, and an electric
generator associated with the main expansion turbine for generating
electric power. The method provides stored compressed air from a
compressed air storage. The compressed air originating from the
storage is heated. The heated, compressed air is expanded in an air
expander for producing additional electric power. Airflow is
extracted from the expander and is injected into the combustion
turbine assembly upstream of the combustors with injection flow
parameters of the injected airflow being consistent with flow
parameters of the main compressor at the injection point.
[0011] Other objects, features and characteristics of the present
invention, as well as the methods of operation and the functions of
the related elements of the structure, the combination of parts and
economics of manufacture will become more apparent upon
consideration of the following detailed description and appended
claims with reference to the accompanying drawings, all of which
form a part of this specification.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The invention will be better understood from the following
detailed description of the preferred embodiments thereof, taken in
conjunction with the accompanying drawings, wherein like reference
numerals refer to like parts, in which:
[0013] FIG. 1 is a schematic illustration of a combustion turbine
power generation system with power augmentation using a compressed
air storage supplying compressed air, preheated in a heat
exchanger, to an expander that expands the air for providing
additional power with expander exhaust airflow being injected
upstream of the combustors, provided in accordance with the
principles of the present invention.
[0014] FIG. 2 is a schematic illustration of a combustion turbine
power generation system with power augmentation using a compressed
air storage supplying compressed air, preheated in a heat
exchanger, to an expander that expands the air for providing
additional power with airflow extracted from a stage of the
expander being injected upstream of the combustors, provided in
accordance with the principles of another embodiment of the present
invention.
DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0015] With reference to FIG. 1, a combustion turbine power
generation system with power augmentation, generally indicated as
10, is shown in accordance with an embodiment of the present
invention. The system 10 includes a conventional combustion turbine
assembly, generally indicated at 11, having a main compressor 12
receiving, at inlet 13, a source of inlet air at ambient
temperature and feeding combustors 16 with the compressed air; a
main expansion turbine 14 operatively associated with the main
compressor 12, with the combustors 16 feeding the main expansion
turbine 14, and an electric generator 15 for generating electric
power.
[0016] A compressed air storage 18 is provided that is preferably
an underground storage structure that stores air that is compressed
by at least one auxiliary compressor 20. In the embodiment, the
auxiliary compressor 20 is driven by a motor 21, but can be driven
by an expander or any other source. The auxiliary compressor 20
charges the storage 18 with compressed air during off-peak hours.
An outlet 22 of the storage 18 is preferably connected with a heat
exchanger 24. The heat exchanger 24 also receives exhaust air 25
from the main expansion turbine 14. Instead, or in addition to the
exhaust air 25 from the main turbine 14, the heat exchanger 24 can
receive any externally available source of heat.
[0017] An outlet 26 of the heat exchanger 24 is connected to an
expander 28 that is connected to an electric generator 30. In
accordance with the embodiment, during peak hours, compressed air
is withdrawn from the storage 18, preheated in the heat exchanger
24 and sent to the expander 28. The heated air is expanded though
the expander 28 that is connected to the electric generator 30 and
produces additional power. The exhaust from the expander 28, with
injection flow parameters determined by combustion turbine
limitations and optimization, is injected into the combustion
turbine assembly 11 upstream of combustors 16. Thus, as shown in
FIG. 1, structure 32 communicates with structure 35 to facilitate
the injection of air. In the embodiment, the structures 32 and 35
are preferably piping structures.
[0018] Typical gross power augmentation of a combustion turbine
associated with an air injection technology is 20-25%. The
additional power of the additional expander 28, operating with the
injection airflow of approximately 12-14% (of the combustion
turbine assembly inlet flow) and utilizing a stored compressed air
with the inlet pressure of approximately 60-80 bars (a typical
stored compressed air pressure) preheated in the heat exchanger 24
to the inlet temperature of approximately 480-500 C, is
approximately 5-10% of the combustion turbine assembly 11 power. As
an example, the GE 7241 combustion turbine assembly operating at 35
C could have gross power augmentation of approximately 38-40 MW
with the air injection flow of approximately 12% of the combustion
turbine assembly inlet flow; the expander 28 additional power is
approximately 10 MW with the total power augmentation of
approximately 48-50 MW. The power generation system 10 heat rate is
reduced because the additional expander 28 power is delivered
without any additional fuel flow, i.e. with the zero heat rate.
[0019] This system 10 has the following additional (to original
embodiment with a combustion turbine assembly 11; compressed air
storage 18 and charging compressor 20) components: [0020] The
additional air expander 28 [0021] The heat exchanger 24 recovering
the combustion turbine 14 exhaust heat and feeding the expander 28
BOP piping and specialties
[0022] The overall parameters of the system 10 are optimized based
on the overall plant economics including: [0023] Additional
components capital and operational costs [0024] The combustion
turbine power augmentation [0025] The expander 28 additional
peaking power produced
[0026] FIG. 2 shows another embodiment of the system 10' that is
similar to that of FIG. 1, except that the additional expander 28
expands the preheated compressed stored air from the stored air
pressure to atmospheric pressure resulting in much higher power. In
addition, the expander flow rate is not restricted to the injection
rate allowable by a specific combustion turbine assembly.
Furthermore, the air required for the injection in a combustion
turbine assembly for power augmentation with specific parameters is
extracted from the expander 28 with specific parameters.
[0027] With reference to FIG. 2, the compressed air from the
storage 18 is directed to the heat exchanger 24 that receives heat
from the source of a heat (e.g. exhaust of turbine 14). The heated
air is expanded though the expander 28 that is connected to the
electric generator 30 and produces additional power. The airflow of
expander 28 is a subject for optimization and could be as high as a
combustion turbine inlet flow. The expander 28 has a provision for
an extracted airflow flow with parameters consistent with the
requirements of the air injection technology determined by
combustion turbine assembly limitations. In other words, the
injection flow parameters of the injected airflow are consistent
with flow parameters of the main compressor 12 at an injection
point. The extracted airflow is injected via structure 33 into the
combustion turbine assembly 11 (via structure 35) upstream of the
combustors 16 with a combustion turbine power augmentation of
approximately 20-25%. The remaining airflow in the expander 28 is
expanded though low pressure stages to atmospheric pressure. The
additional power of the expander is a subject of optimization and
could be equal to a combustion turbine power.
[0028] As an example, the GE 7241 combustion turbine operating at
35 C could have gross power augmentation of approximately 38-40 MW
with the extracted (from the additional expander 28) and injected
airflow of approximately 12% of the combustion turbine inlet flow;
the expander additional power could be as high as the combustion
turbine power and is a subject for optimization.
[0029] The use of the expander 28 can be employed in a Combustion
Turbine/Combined Cycle Power Plant. This system preferably includes
the following additional (to the combustion turbine assembly 11;
compressed air storage 18 and charging compressor 20) components:
[0030] The air expander 28, [0031] Heat exchanger 24 recovering the
combustion turbine 14 exhaust heat and feeding the expander 28,
[0032] BOP piping and specialties
[0033] The foregoing preferred embodiments have been shown and
described for the purposes of illustrating the structural and
functional principles of the present invention, as well as
illustrating the methods of employing the preferred embodiments and
are subject to change without departing from such principles.
Therefore, this invention includes all modifications encompassed
within the spirit of the following claims.
* * * * *