U.S. patent application number 12/582720 was filed with the patent office on 2010-02-25 for method of producing power by storing wind energy in the form of compressed air.
Invention is credited to Michael Nakhamkin.
Application Number | 20100043437 12/582720 |
Document ID | / |
Family ID | 42073795 |
Filed Date | 2010-02-25 |
United States Patent
Application |
20100043437 |
Kind Code |
A1 |
Nakhamkin; Michael |
February 25, 2010 |
Method of producing power by storing wind energy in the form of
compressed air
Abstract
A method of producing power stores wind energy in the form of
compressed air in a tower of a wind power plant, releases
compressed air from the tower, and preheats the released compressed
air to produce heated air. The heated air is supplied to an air
expander and the heated air is expanded in the air expander to
produce power.
Inventors: |
Nakhamkin; Michael; (Basking
Ridge, NJ) |
Correspondence
Address: |
MANELLI DENISON & SELTER
2000 M STREET NW SUITE 700
WASHINGTON
DC
20036-3307
US
|
Family ID: |
42073795 |
Appl. No.: |
12/582720 |
Filed: |
October 21, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12285404 |
Oct 3, 2008 |
7614237 |
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12582720 |
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12216911 |
Jul 11, 2008 |
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12285404 |
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12076689 |
Mar 21, 2008 |
7406828 |
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12216911 |
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11657661 |
Jan 25, 2007 |
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12076689 |
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Current U.S.
Class: |
60/645 |
Current CPC
Class: |
F05D 2220/60 20130101;
F02C 6/16 20130101; Y02E 50/11 20130101; F05B 2240/912 20130101;
Y02E 60/15 20130101; F02C 6/14 20130101; Y02E 70/30 20130101; Y02E
60/16 20130101; F01D 15/10 20130101; F02C 7/143 20130101; Y02E
50/10 20130101 |
Class at
Publication: |
60/645 |
International
Class: |
F01K 13/00 20060101
F01K013/00 |
Claims
1-12. (canceled)
13. A method of producing power including: storing wind energy in
the form of compressed air in a tower of a wind power plant,
releasing compressed air from the tower, preheating the released
compressed air to produce heated air, supplying the heated air to
an air expander, and expanding the heated air in the air expander
to produce power.
14. The method of claim 13, further including providing a
generator, associated with the expander, the method includes
producing electric power via the generator.
15. The method of claim 13, wherein the step of storing wind energy
compressing air and storing the compressed air during off-peak
power hours and the step of releasing compressed air includes
releasing the compressed air during peak power hours.
16. The method of claim 13, wherein the step of preheating the
released compressed air includes heating the released compressed
air in a combustor that feeds the air expander.
17. The method of claim 13, wherein the step of preheating the
released compressed air includes providing a source of heat to a
heat exchanger, with the heat exchanger feeding the air
expander.
18-20. (canceled)
Description
[0001] This application is a division of U.S. application Ser. No.
12/285,404, filed on Oct. 3, 2008, now U.S. Pat. No. 7,614,237
which is a continuation-in-part of U.S. application Ser. No.
12/216,911 filed on Jul. 11, 2008 which is a continuation of U.S.
application Ser. No. 12/076,689, filed on Mar. 21, 2008, now U.S.
Pat. No. 7,406,828, which is a division of U.S. application Ser.
No. 11/657,661, filed on Jan. 25, 2007.
TECHNICAL FIELD
[0002] This invention relates to a Compressed Air Energy Storage
(CAES) system and, more particularly, to a CAES system that can
provide substantially instantaneous, synchronous reserve power.
BACKGROUND
[0003] U.S. Pat. Nos. 7,389,644 and 7,406,828 disclose a CAES
plants where a compressor supplies compressed air to an air storage
during off-peak hours and, during peak hours, the stored compressed
air is withdrawn from the storage, is preheated by utilizing the
combustion turbine exhaust gas heat, and then is directed into an
expander that generates the preheated compressed air power in
addition to combustion turbine power. Conventional CAES plant
operations are effective in achieving the prime goal of storing
off-peak energy in the form of the compressed air and then using
the preheated, stored compressed air for generation of the more
needed and higher priced energy during peak hours, i.e., management
of renewable and base power resources.
[0004] Still, electric grids require a number of additional very
important functions such as grid regulation and emergency
synchronous reserve. The grid regulation is easily provided by U.S.
Pat. Nos. 7,389,644 and 7,406,828 that disclose CAES plants with
practically instant load following operation of the CAES plants.
The emergency synchronous reserve function requires very quick
start-up and power delivery. The start-up time of the CAES plants
described in each of U.S. Pat. Nos. 7,389,644 and 7,406,828, the
contents of which are hereby incorporated by reference into this
specification, is dependent on the startup time of combustion
turbines (that can take approximately 20-30 minutes) to utilize the
combustion turbine exhaust gas heat.
[0005] Thus, in a CAES system, there is a need to provide
practically instant synchronous reserve power independent of the
combustion turbine or other power generation structure.
SUMMARY
[0006] An object of the invention is to fulfill the need referred
to above. In accordance with the principles of an aspect of the
present invention, this objective is achieved by providing a CAES
system including a compressor for supplying compressed air to the
air storage, an air storage for storing compressed air, a power
generating structure, a heat exchanger constructed and arranged to
receive heat from the power generating structure and to receive
compressed air from the air storage, at least one auxiliary
combustor for burning fuel and constructed and arranged to receive
compressed air from the air storage, an air expander constructed
and arranged to be fed with heated air from one of the heat
exchanger or the at least one auxiliary combustor and to expand the
heated air, and an electric generator, associated with the
expander, for producing electric power. The system is constructed
and arranged to selectively operate in at least one of the
following power production modes of operation: [0007] a) a main
power production mode wherein the power generating structure is
operable and the at least one auxiliary combustor is inoperable,
with the heat exchanger receiving heat from the power generating
structure and receiving the compressed air from the air storage so
as to heat the compressed air received from the air storage, with
the heat exchanger feeding the heated compressed air to the air
expander, with the air expander expanding the heated compressed air
and the generator providing the electric power in addition to power
produced by the power generating structure, or [0008] b) a
synchronous reserve power mode wherein the at least one auxiliary
combustor is operable and the power generating structure is
inoperable, with compressed air withdrawn from the air storage
being preheated by the at least one auxiliary combustor feeding the
heated compressed air to the air expander, with the air expander
expanding the heated air and the generator providing substantially
immediate start-up power.
[0009] In accordance with another aspect of the invention, a method
of operating a CAES system is provided. The CAES system includes a
compressor for supplying compressed air to the air storage, an air
storage for storing compressed air, a power generating structure, a
heat exchanger constructed and arranged to receive heat from the
power generating structure and to receive compressed air from the
air storage, at least one auxiliary combustor for burning fuel and
constructed and arranged to receive compressed air from the air
storage, an air expander constructed and arranged to be fed with
heated air from one of the heat exchanger or the at least one
auxiliary combustor and to expand the heated air, and an electric
generator, associated with the expander, for producing electric
power. The method includes selectively operating the CAES system in
at least one of following power production modes: [0010] a) a main
power production mode by: [0011] ensuring that the power generating
structure is operable and the at least one auxiliary combustor is
inoperable and, [0012] providing heat from the power generating
structure to the heat exchanger and providing compressed air from
the air storage to the heat exchanger so that the compressed air
received from the air storage is heated in the heat exchanger, with
the heat exchanger feeding the heated compressed air to the air
expander, [0013] expanding the heated compressed air in the
expander, and providing the electric power via the generator in
addition to power produced by the power generating structure, or
[0014] b) a synchronous reserve power mode by: [0015] ensuring that
the power generating structure is inoperable and the at least one
auxiliary combustor is operable, [0016] withdrawing compressed air
from the air storage, [0017] preheating the withdrawn compressed
air in the at least one auxiliary combustor that feeds the air
expander, [0018] expanding heated air received from the at least
one combustor in the air expander and [0019] providing
substantially immediate start-up power via the generator.
[0020] In accordance with another aspect of the invention, a CAES
system includes a compressor for supplying compressed air to the
air storage, an air storage for storing compressed air, a source of
heat, a heat exchanger constructed and arranged to receive heat
from the source of heat and to receive compressed air from the air
storage, at least one auxiliary combustor for burning fuel and
constructed and arranged to receive compressed air from the air
storage, an air expander constructed and arranged to be fed with
heated air from one of the heat exchanger or the at least one
auxiliary combustor and to expand the heated air, and an electric
generator, associated with the expander, for producing electric
power. The system is constructed and arranged to selectively
operate in at least one of the following power production modes of
operation: [0021] a) a first power production mode wherein the at
least one auxiliary combustor is inoperable, with the heat
exchanger receiving heat from the source of heat and receiving
compressed air from the air storage so as to heat the compressed
air received from the air storage, with the heat exchanger feeding
the heated compressed air to the air expander, with the air
expander expanding the heated compressed air and the generator
providing the electric power, or [0022] b) a second, synchronous
reserve power production mode wherein the at least one auxiliary
combustor is operable and the source of heat is not received by the
heat exchanger, with compressed air withdrawn from the air storage
being preheated by the at least one auxiliary combustor that feeds
the air expander, with the air expander expanding the heated air
and the generator providing substantially immediate start-up
power.
[0023] In accordance with another aspect of the invention, a method
of a CAES plant operation includes compressing air and storing wind
energy in the form of the compressed air in a supporting tower of a
wind power plant. The compressed air released from the supporting
tower is preheated to produce heated air. The heated air is
supplied to an air expander. The air expander expands the heated
air and connected to electric generator for producing power.
[0024] 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
[0025] 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:
[0026] FIG. 1 is a schematic illustration of an example of the
typical operation of a CAES system based on my U.S. Pat. No.
7,406,828, with the CAES system based on operating a combustion
turbine assembly wherein during off-peak hours a compressor
supplies compressed air to an air storage, and during peak hours
the compressed air withdrawn from the air storage is preheated in a
heat exchanger utilizing the combustion turbine assembly exhaust
heat, and sent to an air expander that expands the preheated air to
provide electric power generated by the compressed air, with a
fraction of expander's airflow being extracted from the expander
and injected upstream of the combustors of the combustion turbine
assembly for power augmentation of combustion turbine. The total
electric power is the power of the compressed air driven expander
plus the power of augmented combustion turbine. It is noted that
auxiliary combustor 27 is a component added to the system of U.S.
Pat. No. 7,406,828 and is used in a synchronous reserve power
generation mode as described below.
[0027] FIG. 2 is a schematic illustration of the CAES system
presented in FIG. 1 but operating in a synchronous reserve power
generation mode without operating the combustion turbine assembly,
but utilizing an additional combustor to increase the inlet
temperature of the compressed air feeding the expander. The total
electric power is generated by the compressed air driven expander
only.
[0028] FIG. 3 is a schematic illustration of an example of the
typical operation of the CAES system based on my U.S. Pat. No.
7,389,644, with CAES system based on operating a combustion turbine
assembly wherein during off-peak hours compressor supplies
compressed air to an air storage, and during peak hours the
compressed air withdrawn from the air storage is preheated in a
heat exchanger utilizing the combustion turbine assembly exhaust
heat, and sent to an air expander with expanded exhaust flow having
lower than ambient temperature being mixed with inlet flow to the
combustion turbine assembly for power augmentation of combustion
turbine. The total electric power is the power of the compressed
air driven expander plus the power of augmented combustion turbine.
It is noted that auxiliary combustor 27 is a component added to the
system of U.S. Pat. No. 7,389,644 and is used in a synchronous
reserve power generation mode as described below.
[0029] FIG. 4 is a schematic illustration of the CAES system
presented in FIG. 3 but operating in a synchronous reserve power
generation mode without operating the combustion turbine assembly,
but utilizing an additional combustor to increase the expander
inlet temperature. The total electric power is generated by the
compressed air driven expander only.
[0030] FIG. 5 is a schematic illustration of an distributed power
generation system wherein during off-peak hours a compressor
supplies compressed air to an air storage, and the compressed air
withdrawn from the air storage is preheated by a diesel generator
exhaust heat or any source of heat, and is sent to an air expander
that generates electric power.
[0031] FIG. 6 is a sectional view of an example of concrete tower
of a wind power plant for storing compressed air.
DESCRIPTION OF EXAMPLE EMBODIMENTS
[0032] With reference to FIG. 1, a CAES system is shown, generally
indicated as 10, in accordance with an embodiment. The system 10
includes a power generating structure, generally indicated at 11,
in the form of a conventional combustion turbine assembly having a
main compressor 12 receiving, at inlet 13, a source of inlet air at
ambient temperature and feeding at least one main combustor 16 with
the compressed air, a main expansion turbine 14 operatively
associated with the main compressor 12, with the at least one main
combustor 16 feeding the main expansion turbine 14, and an electric
generator 15 for generating electric power.
[0033] As shown in FIG. 1, the system 10 also includes an air
storage 18 that during off-peak hours stores air that is compressed
preferably by at least one auxiliary compressor 20. In the
embodiment, the auxiliary compressor 20 is driven by a motor 23,
but can be driven by an expander or any other source. The auxiliary
compressor 20 supplies compressed air to the air storage 18
preferably during off-peak hours. Although a single compressor 20
is shown, the air storage 18 can be supplied by multiple
compressors or with compressed air from any source of air
compression.
[0034] An outlet 22 of the storage 18 is preferably connected with
a recuperator or heat exchanger 24. The heat exchanger 24 receives
the exhaust gas 25 from the main expansion turbine 14. Thus, the
combustion turbine assembly 11, in addition to generating the
electric power, provides a source of heat. Instead, or in addition
to the exhaust gas 25 from the expansion turbine 14 of the
combustion turbine assembly 11, the heat exchanger 24 can receive
any externally available source of heat, as will be explained more
fully below. An outlet 26 of the heat exchanger 24 is connected to
at least one auxiliary combustor 27, with an outlet 28 of the
combustor 27 being connected to an air expander 30 that is
connected to an electric generator 32.
[0035] In accordance with the embodiment, in a main power
production mode of operation of the system 10, preferably during
peak hours, and with the auxiliary combustor 27 inoperable,
compressed air from the storage 18 is directed to the heat
exchanger 24 that receives heat from the source of heat (e.g.,
exhaust of turbine 14). The heated air is expanded through the
expander 30 that is connected to the electric generator 32 and
produces the electric power generated by the compressed air in
addition to the combustion turbine assembly power. The airflow of
expander 30 is a subject for optimization and driven by the
required compressed air generated power. The expander 30 has a
provision for an extracted airflow flow with parameters consistent
with the requirements of the air injection power augmentation
technology determined by combustion turbine assembly limitations
and can be a subject of optimization. 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. Thus,
injection can be limited or restricted under certain conditions.
For example, based on combustion turbine manufacturer published
data, injection at low ambient temperatures may not be permitted or
possible, or injection may not be permitted or possible due to
accessibility to injection points, or injection may not occur due
to operational judgments. The extracted airflow is injected via
structure 36 into the combustion turbine assembly 11 preferably
upstream of the at least one main combustor 16 with a combustion
turbine maximum power augmentation of approximately up to 20-25%.
The remaining airflow in the expander 30 is expanded though low
pressure stages to atmospheric pressure. Thus, when injection is
possible or desired, not all airflow from the expander 30 is
exhausted to atmospheric pressure.
[0036] FIG. 2 shows a synchronous reserve power mode of operation
of the system 10 of FIG. 1. In this mode, the at least one
combustor 27 is operable and the combustion turbine assembly 11 is
not operable. Furthermore, since the combustion turbine assembly 11
is not operable, the heat exchanger 24 is not receiving exhaust
heat in this mode of operation. Thus, compressed air is withdrawn
from the storage 18 and is preheated by the at least one auxiliary
combustor 27, for burning fuel, that feeds the expander 30. The
heated air is expanded though the expander 30 that is connected to
the electric generator 32 for substantially immediate start-up for
synchronous reserve power operation, independent of the combustion
turbine assembly 11 operation.
[0037] With reference to FIG. 3, a CAES system which is shown,
generally indicated as 10', in accordance with another embodiment.
The system 10' includes the same components as in FIG. 1. In a main
power production mode of operation of the system 10', preferably
during peak hours, and with the auxiliary combustor 27 inoperable,
compressed air is withdrawn from the storage 18 and directed to the
heat exchanger 24 that receives heat from the source of heat (e.g.,
exhaust of turbine 14). The heated air is expanded through the
expander 30 that is connected to the electric generator 32 and
produces the electric power generated by the compressed air in
addition to combustion turbine assembly power. Since the expander
30 reduces the pressure of the compressed air, the temperature of
the compressed air is reduced. Thus, cold (lower than ambient
temperature) air of the expander 30 exhaust is mixed, via structure
36, with the ambient air at inlet 13, reducing the overall
temperature of the inlet air prior to being received by the main
compressor 12. In the embodiment, the structure 36 is piping
connected between an exhaust of the expander 30 and the inlet 13 to
the main compressor 12. The airflow of expander 30 is a subject for
optimization and driven by the required compressed air generated
power. It can be appreciated that instead of all exhaust of the
expander 30 being mixed with ambient inlet air, only a portion of
the exhaust of the expander 30 can be mixed with the ambient inlet
air, by connection the piping 36 to a stage of the expander 30,
with the remainder being exhausted to atmosphere.
[0038] FIG. 4 shows a synchronous reserve power mode of operation
of the system 10' of FIG. 3. In this mode, the at least one
auxiliary combustor 27 is operable and the combustion turbine
assembly 11 is not operable. Furthermore, since the combustion
turbine assembly 11 is not operable, the heat exchanger 24 is not
receiving exhaust heat in this mode of operation. Thus, compressed
air is withdrawn from the storage 18 and is preheated by the at
least one auxiliary combustor 27 that feeds the expander 30. The
heated air is expanded though the expander 30 that is connected to
the electric generator 32 for immediate start-up for synchronous
reserve power requirements independent of the combustion turbine
assembly 11 operation.
[0039] With reference to FIG. 5, a CAES system which is shown,
generally indicated as 100, in accordance with another embodiment
of the present invention. The system 100 is similar to the systems
of FIGS. 1 and 3, but, for distributed power generation
applications, the combustion turbine assembly 11 is replaced with a
diesel generator 102 or any other power producing structure that
provides a heat source, or any source of heat. The exhaust 25 of
the power producing structure 102, or any heat source is received
by the heat exchanger 24. Thus, in a main power producing mode of
operation, the stored compressed air withdrawn from the storage 18,
is preheated in the heat exchanger 24 by utilizing the diesel
generator 102 exhaust gas heat (or the heat from another power
producing heat source or heat from any heat source) and is then
directed into the expander 30 that generates the compressed air
power in addition to power provided by the diesel generator 102. In
this mode, the combustor 27 is not operable.
[0040] The system 100' can also operate in a synchronous reserve
power mode of operation when the diesel generator 102 or other
power producing structure is not operable and with the at least one
combustor 27 operable, in a manner similar to that discussed above
with regard to FIGS. 2 and 4.
[0041] The air storage 18 can be a below ground storage in various
geological formations or above ground storage in pressure
vessels/piping that are significantly more expansive than
underground storages. Since one of the prime functions of a CAES
plant is associated with load management of wind power plants, in
accordance with an embodiment of FIG. 6, the air storage 18' can be
the supporting tower 104 of a wind power plant 106. Wind power
plants are typically installed on the top of the supporting
concrete towers 104 with significant diameter e.g., 10-20 feet and
wall thickness 2-3 feet to support the weight and stresses of the
wind power plant and to provide an internal chamber 108 for
maintenance and support operations. To store compressed air, the
chamber 108 shall be slightly modified to provide appropriate seals
110 especially at a top thereof. Thus, the supporting towers 104
can be utilized for the compressed air storage replacing typical
underground storage or the storage of the compressed air in the
above ground pressure vessels/piping. Preferably during the
off-peak power hours without usage requirements, the wind energy,
in the form of the compressed air, will be sent to inlet 112/114 of
the supporting tower 104 and be stored inside the tower 104. If
maintenance is required, the compressed air can be removed from the
tower 104. During peak power hours, the stored compressed air can
be directed from exit 112/114 of the supporting tower, be preheated
and sent to expanders for generation of the more needed and higher
price energy for example, in the manner discussed above with regard
to FIGS. 1 and 3.
[0042] 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 scope of the following claims.
* * * * *