U.S. patent application number 11/979586 was filed with the patent office on 2008-03-13 for work extraction arrangement.
This patent application is currently assigned to Rolls-Royce plc. Invention is credited to Paul Fletcher, James I. Oswald.
Application Number | 20080060340 11/979586 |
Document ID | / |
Family ID | 30130195 |
Filed Date | 2008-03-13 |
United States Patent
Application |
20080060340 |
Kind Code |
A1 |
Fletcher; Paul ; et
al. |
March 13, 2008 |
Work extraction arrangement
Abstract
A work extraction arrangement (10) comprises a cooling assembly
(12) for cooling a gas to provide a working fluid capable of doing
work. The arrangement (10) further includes storage means (14) for
storing the working fluid and a turbine assembly (18) for
extracting work from the working fluid. A fluid delivery assembly
(16) is also provided to deliver the working fluid to the turbine
assembly (18).
Inventors: |
Fletcher; Paul; (Rugby,
GB) ; Oswald; James I.; (Hinckley, GB) |
Correspondence
Address: |
MANELLI DENISON & SELTER
2000 M STREET NW SUITE 700
WASHINGTON
DC
20036-3307
US
|
Assignee: |
Rolls-Royce plc
|
Family ID: |
30130195 |
Appl. No.: |
11/979586 |
Filed: |
November 6, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11008659 |
Dec 10, 2004 |
7305832 |
|
|
11979586 |
Nov 6, 2007 |
|
|
|
Current U.S.
Class: |
60/39.6 ;
60/772 |
Current CPC
Class: |
F02C 6/16 20130101; Y02E
60/16 20130101; Y02E 60/15 20130101 |
Class at
Publication: |
060/039.6 ;
060/772 |
International
Class: |
F02C 5/00 20060101
F02C005/00; F02C 1/00 20060101 F02C001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 13, 2003 |
GB |
0328950.1 |
Claims
1. A work extraction arrangement comprising a cooling assembly for
cooling a gas to provide a working fluid capable of doing work,
storage means for storing the working fluid, a turbine assembly for
extracting work from the working fluid, and a fluid delivery
assembly for delivering the working fluid to the turbine
assembly.
2. A work extraction arrangement according to claim 1 wherein the
fluid delivery assembly comprises a pumping means.
3. A work extraction arrangement according to claim 2 wherein the
fluid delivery assembly comprises a main compressor, whereby when
the fluid delivered to the main compressor is in the form of a gas,
the main compressor can compress the gas
4. A work extraction arrangement according to claim 3 wherein the
main compressor comprises a compressor of a gas turbine engine.
5. A work extraction arrangement according to claim 2 wherein the
pumping means comprises a pump, suitable for pumping at least
partially liquefied gas.
6. A work extraction arrangement according to claim 1 wherein the
turbine assembly comprises at least one main turbine for extracting
work from the working fluid, and a combustor for combusting the
working fluid when the working fluid comprises a combustible
gas.
7. A work extraction arrangement according to claim 6 wherein the
combustor is arranged upstream of the main turbine assembly and the
main turbine assembly is operable by the combustion products of the
working fluid.
8. A work extraction arrangement according to claim 1 wherein the
work extraction arrangement comprises an electricity generator,
driven by the turbine assembly.
9. A work extraction arrangement according to claim 1 wherein the
turbine assembly comprises a turbine assembly of a gas turbine
engine.
10. A work extraction arrangement according to claim 1 wherein the
cooling assembly comprises a cooling cycle compressor for
compressing the gas for cooling purposes.
11. A work extraction arrangement according to claim 10 wherein the
cooling assembly comprises a heat extractor for extracting heat
from the compressed gas.
12. A work extraction arrangement according to claim 10 wherein the
heat extractor comprises a heat exchanger to exchange heat with the
surroundings.
13. A work extraction arrangement according to claim 1 wherein the
cooling assembly comprises a cooling cycle turbine to extract work
from the compressed gas thereby cooling the gas to provide said
working fluid.
14. A work extraction arrangement according to claim 1 wherein the
working fluid provided by the cooling assembly is in liquid or
gaseous form.
15. A work extraction arrangement according to claim 1 wherein the
work extraction arrangement comprises a heater for heating the
working fluid downstream of the fluid delivery assembly.
16. A work extraction arrangement according to claim 15 wherein the
working fluid heater comprises a heat exchanger, and is arranged to
exchange heat with the surroundings.
17. A work extraction arrangement according to claim 1 wherein the
work extraction arrangement further comprises a recuperating heat
exchanger, whereby exhaust gases from the main turbine can exchange
heat with gas to be delivered to the combustor.
18. A method of extracting work from a gas, comprising cooling the
gas to provide a working fluid capable of doing work, storing the
working fluid, delivering the working fluid to a turbine assembly,
whereby work can be extracted from the working fluid by the turbine
assembly.
19. A method according to claim 18 wherein the working fluid is
compressed during its delivery to the turbine assembly.
20. A method according to claim 18 wherein the working fluid is
pumped during its delivery to the turbine assembly.
21. A method according to claim 18 wherein the turbine assembly
comprises a main turbine and a combustor and the working fluid is
combusted upstream of the main turbine and the main turbine is
operable by the combustion products of the working fluid.
22. A method according to claims 18 wherein the extraction of work
from the working fluid involves driving an electricity generator to
generate electricity.
23. A method according to claim 18 wherein the step of cooling the
gas comprises compressing the gas for cooling purposes, extracting
heat from the compressed gas and thereafter extracting preliminary
work from the compressed gas thereby cooling the gas to provide
said working fluid.
24. A method according to claim 23 wherein the step of extracting
preliminary work from the compressed gas comprises driving a
cooling cycle turbine with said compressed gas.
25. A method according to any of claim 1 wherein the working fluid
is heated during its delivery to the turbine assembly.
26. A method according to claim 25 wherein the step of heating the
working fluid comprises exchanging heat with the surroundings.
Description
[0001] This invention relates to work extraction arrangements. More
particularly, but not exclusively, the invention relates to
electricity generating apparatus using liquefied air.
[0002] The generation of electricity by burning fuel in a gas
turbine engine requires the fuel to be piped to the engine. The
fuel occurs in offshore fields and sometimes these fields are
located at distances which make the extraction of the fuel
unattractive. These fields are known as "stranded fields". A recent
approach is to locate the gas turbine engine at the stranded fields
to burn the fuel and generate electricity. Electric cables are
provided to carry the electricity to the grid/users. Additionally
wind turbines have been located at the stranded fields and use the
same electric cable. The turbines are easily switched on/off to
match the load demand on the grid. However, the wind turbines may
only provide power when the wind blows.
[0003] According to one aspect of this invention, there is provided
a work extraction arrangement comprising a cooling assembly for
cooling a gas to provide a working fluid capable of doing work,
storage means for storing the working fluid, a turbine assembly for
extracting work from the working fluid, and a fluid delivery
assembly for delivering the working fluid to the turbine
assembly.
[0004] According to another aspect of this invention there is
provided a method of extracting work from a gas, comprising cooling
the gas to provide a working fluid capable of doing work, storing
the working fluid, delivering the working fluid to a turbine
assembly whereby work can be extracted from the working fluid by
the turbine assembly.
[0005] Preferably, the fluid delivery assembly comprises a pumping
means. In one embodiment, the fluid delivery assembly may comprise
a pump, which may be suitable for pumping a liquefied gas. The pump
may be suitable for pumping a mixture of gas and liquefied gas.
Alternatively, the pump may be suitable for pumping a wholly
liquefied gas. In another embodiment, the fluid delivery assembly
comprises a main compressor, whereby when the fluid delivered to
the main compressor is in the form of a gas, the main compressor
can compress the gas. The fluid delivered to the main compressor
may be in the form of a mixture of a gas and liquefied gas. The
main compressor may be a compressor of a gas turbine engine.
[0006] The turbine assembly may comprise at least one main turbine
for extracting work from the working fluid, and may include a
combustor for combusting the working fluid when the working fluid
comprises a combustible gas. Preferably, the combustor is arranged
upstream of the turbine assembly.
[0007] Preferably, the main turbine is operable by the combustion
products of the working fluid.
[0008] The work extraction arrangement may comprise an electricity
generator, which may be driven by the turbine assembly. In one
embodiment, the turbine assembly may be a turbine assembly of a gas
turbine engine.
[0009] The cooling assembly may comprise a cooling cycle compressor
for compressing the gas for cooling purposes. The cooling assembly
may comprise a heat extractor for extracting heat from the
compressed gas. The heat extractor may comprise a heat exchanger to
exchange heat with the surroundings, e.g. the sea or the
atmosphere.
[0010] The cooling assembly may comprise a cooling cycle turbine to
extract preliminary work from the compressed gas thereby cooling
the gas to provide said working fluid.
[0011] The working assembly may be driven by a wind turbine or
other renewable energy source. Alternatively, the cooling assembly
may be driven by electricity at night time, which is less expensive
than electricity produced during daylight hours.
[0012] The working fluid provided by the cooling assembly may be in
liquid or gaseous form.
[0013] In one embodiment, the work extraction arrangement may
comprise a heater for heating the working fluid downstream of the
fluid delivery assembly. The working fluid heater may comprise a
heat exchanger. Preferably, the heat exchanger is arranged to
exchange heat with the surroundings, for example, the sea or the
atmosphere.
[0014] The work extraction arrangement may further comprise a
recuperating heat exchanger, whereby exhaust gases from the main
turbine can exchange heat with gas to be delivered to the
combustor.
[0015] Embodiments of the invention will now be described by way of
example only, with reference to the accompanying drawings in
which:
[0016] FIG. 1 shows a schematic diagram of a first embodiment of a
work extraction arrangement
[0017] FIG. 2 is a schematic diagram of a second embodiment of a
work extraction arrangement; and
[0018] FIG. 3 is a schematic diagram of a third embodiment of a
work extraction arrangement.
[0019] Referring to FIG. 1, there is shown a work extraction
arrangement 10 comprising a cooling assembly 12 for cooling and
liquefying a gas, for example, air, to produce a working fluid,
such as liquefied air. The arrangement also includes storage means
14 for storing the liquefied air, a fluid delivery assembly 16 for
delivering the liquefied air to a turbine assembly 18 to extract
work from the working fluid.
[0020] A heat exchanger 20 is provided downstream of the fluid
delivery assembly 16 to extract heat from the atmosphere and heat
the liquefied air, as represented by the arrow A. In the heat
exchanger 20, the liquefied air is heated to provide gaseous
air.
[0021] Downstream of the turbine assembly 18 there is provided an
alternator 22 for generating electrical power 23. The alternator 22
is driven by the turbine assembly 18, as explained below.
[0022] The cooling assembly 12 comprises a wind turbine 24 which
drives a compressor 26 having an air inlet 28. In another
embodiment, the compressor 26 could be driven by an electric motor,
which is powered by cheaper electricity during the night. Air
compressed by the compressor 28 passes through a heat exchanger 30
where heat is extracted and transferred to the surroundings, for
example the sea or the atmosphere, as represented by the arrow B.
The cooler air is passed to a cooling turbine 32 which allows the
compressed air to expand. As the compressed air expands through the
cooling turbine 32, work and heat are extracted therefrom to
liquefy the air. The liquid air is passed to the storage means 14,
which may be in the form of suitable storage tanks for storing
liquid air at about 80K.
[0023] When it is desired to generate electricity, for example,
during peak hours, the air is supplied from the storage means 14 to
the delivery assembly 16. In the embodiment shown in FIG. 1, the
delivery assembly comprises a pump 38. The air passes from the pump
38 through the heat exchanger 20, in this embodiment, the air is in
a liquid or at least a partially liquid state when it passes
through the pump 38.
[0024] The air is heated in the heat exchanger 20 by extracting
heat from the surroundings, for example, the sea or the atmosphere.
The air is then passed through a recuperating heat exchanger 40
whereby heat is exchanged with exhaust gasses from the turbine
assembly 18 to further heat the air. During these heating stages,
the air is converted substantially wholly to a gas.
[0025] The turbine assembly 18 comprises a main turbine 42, and a
combustor 44. The gas from the recuperating heat exchanger 40 is
passed into the combustor 44 where it is combusted and the gaseous
combustion products expand through the main turbine 42 causing it
to rotate. The main turbine 42 is drivingly connected by the shaft
46 to the alternator 22 to drive the alternator 22 and generate the
electrical power 23. Gases from the main turbine 42 are exhausted
via the recuperating heat exchanger 40 to heat the incoming
air.
[0026] FIG. 2 shows a further embodiment, which comprises a
modification to the embodiment shown in FIG. 1. The embodiment
shown in FIG. 2 comprises many of the same features as shown in
FIG. 1, and these have been designated within the same reference
numerals. In FIG. 2, the storage means 14 is replaced by storage
means 114, which is constructed to store the air in only partially
liquefied form or wholly in the form of a gas. Also, the pump 38 is
replaced by a main compressor 138 which is drivingly connected by a
shaft 139 to the main turbine 42.
[0027] Air from the storage means 14 may be only partially
liquefied or wholly in the form of a gas. The air passes to the
main compressor 138 to be compressed. For example, if the inlet
temperature of the main compressor 138, it is compressed. For
example, if the inlet temperature of the main compressor 138 is
80K, and the compression ratio of the main compressor 138 is 15:1,
the compressed air leaves the main compressor 138 at about
173K.
[0028] The compressed air passes from the compressor 138 through
the heat exchanger 20 to extract heat from the surroundings, and
then through the recuperating heat exchanger 40 to extract heat
from the exhaust gases of the main turbine 42.
[0029] The air then passes through the combustor 44 to be combusted
and expands through the main turbine 42 to drive the main turbine
42 which, in turn, drives the main compressor 138 via the shaft
139. The main turbine 42 also drives the alternator 22 via the
shaft 46.
[0030] FIG. 3 shows a modification, which comprises many of the
features shown in FIG. 1, and these have been designated with the
same reference numerals.
[0031] The embodiment shown in FIG. 3 differs from the embodiment
shown in FIG. 1 downstream of the storage means 14.
[0032] In FIG. 3, liquid air from the storage means 14 is mixed
with ambient air from the atmosphere in a mixing assembly 50. The
mixing assembly 50 comprises a conduit 52 having an inlet 56 for
atmospheric air to enter the conduit 52. A spray means 54 is
provided to spray liquid air from the storage means 14 into the
conduit 52. As a result, the liquid air at 80K is mixed with
incoming atmospheric air, which is likely to be at approximately
288K. The temperature of the air entering the main compressor 138
is cooled below the temperature of atmospheric air.
[0033] The main compressor 138 is connected to the main turbine 42
by the shaft 139 and air exiting from the main compressor 138 is
combusted through the combustor 44 to drive the turbine 42 which in
turn drives the main compressor 138. In addition, the turbine 42 is
also connected by the shaft 46 to the alternator 22 to generate
electricity 23.
[0034] There is thus described an advantageous apparatus for
providing air to drive a turbine for use in the production of
electricity at a generator 22.
[0035] Various modifications can be made without departing from the
scope of the invention, for example, the air as stored in the
storage means 14 could be cool gaseous air, rather than liquid
air.
[0036] Whilst endeavouring in the foregoing specification to draw
attention to those features of the invention believed to be of
particular importance it should be understood that the Applicant
claims protection in respect of any patentable feature or
combination of features hereinbefore referred to and/or shown in
the drawings whether or not particular emphasis has been placed
thereon.
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