U.S. patent application number 12/817627 was filed with the patent office on 2011-12-22 for method and system for periodic cooling, storing, and heating of atmospheric gas.
This patent application is currently assigned to AIR PRODUCTS AND CHEMICALS, INC.. Invention is credited to John Frederick CIRUCCI, Donn Michael HERRON, Paul HIGGINBOTHAM, Ronald Martin PEARLSTEIN, Paul Joseph PERSICO, Robert VERO, Jianguo XU.
Application Number | 20110308275 12/817627 |
Document ID | / |
Family ID | 44352290 |
Filed Date | 2011-12-22 |
United States Patent
Application |
20110308275 |
Kind Code |
A1 |
XU; Jianguo ; et
al. |
December 22, 2011 |
METHOD AND SYSTEM FOR PERIODIC COOLING, STORING, AND HEATING OF
ATMOSPHERIC GAS
Abstract
Disclosed is a method and a system. The method and system
involve compressing an atmospheric gas stream to form a
supercritical atmospheric gas stream, forming at least a first
stream from the supercritical atmospheric gas stream, directing the
first stream to a regenerator for cooling to form a first cooled
stream, directing the first cooled stream from the regenerator,
expanding the first cooled stream to form a liquefied atmospheric
gas stream, storing at least a portion of the liquefied atmospheric
gas stream, pressurizing at least a portion of the stored portion
of the liquefied atmospheric gas stream, and heating at least a
portion of a pressurized liquefied atmospheric gas stream in the
regenerator. In the method and system, refrigeration below the
critical temperature of the atmospheric gas is directly or
indirectly provided to at least one portion of the system from a
non-combustible source.
Inventors: |
XU; Jianguo; (Wrightstown,
PA) ; VERO; Robert; (Emmaus, PA) ; HERRON;
Donn Michael; (Fogelsville, PA) ; PERSICO; Paul
Joseph; (Macungie, PA) ; PEARLSTEIN; Ronald
Martin; (Macungie, PA) ; CIRUCCI; John Frederick;
(Schnecksville, PA) ; HIGGINBOTHAM; Paul;
(Guildford, GB) |
Assignee: |
AIR PRODUCTS AND CHEMICALS,
INC.
Allentown
PA
|
Family ID: |
44352290 |
Appl. No.: |
12/817627 |
Filed: |
June 17, 2010 |
Current U.S.
Class: |
62/615 |
Current CPC
Class: |
F25J 1/0037 20130101;
F25J 1/004 20130101; F25J 1/0035 20130101; F25J 2240/10 20130101;
F25J 1/0221 20130101; F25J 2205/24 20130101; F25J 1/0202 20130101;
F25J 2270/06 20130101; F25J 1/0042 20130101; F25J 1/0225 20130101;
Y02E 60/16 20130101; F25J 2270/908 20130101; F25J 2210/40 20130101;
F02C 1/04 20130101; F25J 2270/91 20130101; F25J 1/0012 20130101;
F25J 1/0045 20130101; F25J 1/0264 20130101; F25J 2210/06 20130101;
F25J 2210/42 20130101; Y02E 60/15 20130101; F02C 6/16 20130101;
F25J 2240/90 20130101; F25J 1/0251 20130101 |
Class at
Publication: |
62/615 |
International
Class: |
F25J 1/02 20060101
F25J001/02 |
Claims
1. A regeneration method for periodic cooling, storing, and heating
of atmospheric gas, the method comprising: compressing an
atmospheric gas stream to above a predetermined pressure to form at
least a supercritical atmospheric gas stream, the predetermined
pressure being about the critical pressure for the atmospheric gas
stream; forming at least a first stream from the supercritical
atmospheric gas stream; directing the first stream to a regenerator
for cooling to form at least a first cooled stream; directing the
first cooled stream from the regenerator; expanding the first
cooled stream to form at least a liquefied atmospheric gas stream;
storing at least a portion of the liquefied atmospheric gas stream
as a stored liquefied atmospheric gas; pressurizing at least a
portion of the stored liquefied atmospheric gas to above a second
predetermined pressure to form a pressurized liquefied atmospheric
gas stream, the second predetermined pressure being about the
critical pressure of the liquefied atmospheric gas; and heating at
least a portion of the pressurized liquefied atmospheric gas stream
in the regenerator; wherein refrigeration below the predetermined
temperature is directly or indirectly provided from an external
non-combustible source to one or more of the atmospheric gas
stream, the supercritical atmospheric gas stream, the first stream,
the first cooled stream, the liquefied atmospheric gas stream, and
the pressurized liquefied atmospheric gas stream, the predetermined
temperature being about the critical temperature of the liquefied
atmospheric gas stream.
2. The method of claim 1, further comprising: dividing the
supercritical atmospheric gas stream into at least the first stream
and a second stream; directing the second stream to an indirect
heat exchanger and cooling at least a portion of the second stream
to form at least a second cooled stream; combining the first cooled
stream and the second cooled stream.
3. The method of claim 2, wherein the dividing occurs during a
first operational period, the first operational period being during
off-peak operation.
4. The method of claim 3, wherein the heating of the portion of the
pressurized liquefied atmospheric gas stream in the regenerator
occurs during a second operational period, the second operational
period being during peak operation.
5. The method of claim 4, wherein the dividing occurs during the
first operational period and the second operational period.
6. The method of claim 4, wherein the second operational period has
a briefer duration than the first operational period.
7. The method of claim 2, further comprising directing at least a
portion of the second supercritical atmospheric gas stream from the
indirect heat exchanger to an expander.
8. The method of claim 2, further comprising: directing an exhaust
stream from the indirect heat exchanger to a phase separator;
directing a vapor stream from the phase separator to the indirect
heat exchanger; heating the vapor stream to form a heated
atmospheric gas stream; and recycling the heated atmospheric gas
stream to a booster compressor, the booster compressor being
arranged and disposed for compressing the atmospheric gas
stream.
9. The method of claim 1, wherein at least a portion of the
refrigeration is provided by a liquid air or liquid nitrogen
stream.
10. The method of claim 1, further comprising dividing the
supercritical atmospheric gas into a third stream and directing the
third stream to an expander.
11. The method of claim 1, wherein the first cooled stream is
expanded by a dense fluid expander.
12. The method of claim 1, further comprising directing the heated
portion of the pressurized liquefied atmospheric gas stream to a
heat exchanger, the heat exchanger being configured to transfer
heat from an exhaust stream of a gas turbine.
13. The method of claim 1, further comprising directing a
regenerator-heated atmospheric gas stream to an expander to form an
expanded stream, and directing the expanded stream to an air
separation system, the regenerator-heated atmospheric gas stream
being a pressurized atmospheric gas stream heated by the
regenerator.
14. The method of claim 1, further comprising directing a
regenerator-heated atmospheric gas stream to an expander to form at
least an expanded stream, and directing the expanded stream to a
data center for cooling, the regenerator-heated atmospheric gas
stream being a pressurized atmospheric gas stream heated by the
regenerator.
15. The method of claim 1, further comprising directing a
regenerator-heated atmospheric gas stream to a heat exchanger of a
cryogenic air separation plant, the regenerator-heated atmospheric
gas stream being a pressurized atmospheric gas stream heated by the
regenerator.
16. The method of claim 1, further comprising heating a
regenerator-heated atmospheric gas stream by an exhaust stream of a
gas turbine, the regenerator-heated atmospheric gas stream being a
pressurized atmospheric gas stream heated by the regenerator.
17. The method of claim 1, wherein at least a portion of the
pressurized liquefied atmospheric gas stream heated in the
regenerator is formed from the stored portion of the liquefied
atmospheric gas stream.
18. The method of claim 1, wherein at least a portion of the
pressurized liquefied atmospheric gas stream heated in the
regenerator is formed from a source other than the stored portion
of the liquefied atmospheric gas stream.
19. A system operably configured to perform the method of claim
1.
20. A system for periodic cooling, storing, and heating of
atmospheric gas, the system comprising: a compressor configured to
compress an atmospheric gas stream to above a predetermined
pressure to form at least a supercritical atmospheric gas stream,
the predetermined pressure being about the critical pressure for
the atmospheric gas stream; a regenerator configured to receive a
first stream formed by the supercritical gas stream and form a
first cooled stream; a pressure reducing device configured to
reduce pressure of the first cooled stream and disposed to form at
least a liquefied atmospheric gas stream; a container for storing
at least a portion of the liquefied atmospheric gas stream as
stored liquefied atmospheric gas; a pressure raising device
configured to pressurize the stored liquefied atmospheric gas to
above a predetermined pressure, the predetermined pressure being
about the critical pressure of the atmospheric gas; and a
non-combustible external refrigeration source configured to provide
refrigeration below a predetermined temperature to at least one
portion of the system, the predetermined temperature being about
the critical temperature of the liquefied atmospheric gas stream.
Description
FIELD OF THE INVENTION
[0001] The present invention is directed to a method and system for
periodic cooling, storing, and heating of atmospheric gas. More
specifically, the present invention is directed to a method and
system involving a regeneration cycle for atmospheric gas.
BACKGROUND OF THE INVENTION
[0002] Known systems can cool pressurized air obtained during
off-peak electricity demand hours (off-peak hours) and vaporize the
pressurized air under pressure during peak electricity demand hours
(peak hours).
[0003] Japanese Patent Application, JP4-132837A, which is hereby
incorporated by reference in its entirety, describes a gas turbine
power generation facility comprising a gas turbine for driving a
power generator, a liquefaction facility for liquefying air, a
storage container for storing liquefied fluid, and a vaporization
facility for vaporizing the liquefied fluid and feeding the product
to a gas turbine burner. When the liquefied fluid is pumped from
the storage container, it is vaporized and directed to the gas
turbine burner. This facility suffers from several drawbacks. For
example, liquefaction of air is carried out by using a dedicated
liquefier, which can be inefficient. In addition, the vaporization
of the liquefied fluid and transferring of the refrigeration can be
inefficient based upon including multiple heat transfer steps.
[0004] Japanese Patent Application, JP4-127850, which is hereby
incorporated by reference in its entirety, describes a liquid air
storage electricity generation system that cools, liquefies, and
stores air under normal pressure. The liquid air is warmed and
high-pressure air is extracted as required. The high-pressure air
is used to drive an electricity-generating turbine and generate
electricity. This system suffers from several drawbacks. For
example, although use of refrigeration in liquefied natural gas
vaporization can reduce energy needs for air liquefaction,
liquefied natural gas is not always available. In addition, as a
combustible gas, liquefied natural gas involves safety concerns for
storage and transport, and more importantly, the heat exchange of
liquefied natural gas, a combustible material, with an oxidizing
gas (for example, air).
[0005] Japanese Patent Application, JP4-191419, which is hereby
incorporated by reference in its entirety, describes methods used
to supply air at a constant specified pressure to a combustion
temperature. In a high-loss method, pressure is increased to a
pressure substantially higher than a specified pressure, and the
pressure is reduced to a constant pressure during use. In a
high-risk method, pressure is raised to a specified level using a
separate water head created by sea water, river water, lake water,
or the like. In the methods of the JP4-191419 patent, air is
liquefied and is reduced in volume as compared with the volume
existing at the atmospheric pressure. The liquid is vaporized and
refrigeration is stored. The stored refrigeration can be used for
the precooling of air aspirated by the air liquefied to reduce the
consumption of motive power by the compressor and to reduce the
rate at which electric power is consumed in the production of
liquid air. This method suffers from the drawback that it does not
provide an efficient process for liquefying air and vaporizing the
stored liquid air.
[0006] Hitachi (Hidefumi Araki, Mitsugu Nakabaru, and Kooichi
Chino, Heat Transfer--Asian Research, 31 (4), 2002), which is
hereby incorporated by reference in its entirety, describes high
pressure air being sent to a combustor of a gas turbine during peak
hours. Such a cycle involves a precooled regenerator. Precooling
may be achieved by vaporization of liquefied natural gas. In some
areas, liquefied natural gas may be unavailable. In addition, as a
combustible gas, liquefied natural gas involves safety concerns for
storage and transport and more importantly, the heat exchange of
liquefied natural gas, a combustible material, with an oxidizing
gas (for example, air). Additionally, Hitachi discusses extended
cooling by including a regeneration medium such as pebbles or
concrete. As such, operation of the precooled regenerator, as
disclosed in Hitachi, can result in the regenerator warming up over
cycles due to heat leak, heat introduced by machinery such as
liquid air pumps, and the heat transfer temperature difference
needed for heat transfer to take place in the regenerator and other
heat exchangers if the pressure of the air being cooled is the same
as or similar to that of the air being heated, so such a process is
not sustainable. If the pressure of the air to be heated is much
lower than that of the air being cooled, the process becomes rather
inefficient.
[0007] What is needed is a method and system for cooling and
storing an atmospheric gas during a first operational period of a
process cycle and heating the atmospheric gas during a second
operational period, wherein the method and system operation is
sustainable, reliable, and safe. Sustainability desirably includes
temperatures and pressures of streams in the system, especially
those of lower temperature, at the same phase of the periodic
operation being kept substantially constant after weeks or months
of operation of the system. Reliability desirably includes the use
of materials and equipment that are not constrained by the presence
of a large quantity of another material. Safety desirably includes
use of non-combustible materials in the system.
SUMMARY OF THE INVENTION
[0008] One aspect of the present disclosure includes a regeneration
method for periodic cooling, storing, and heating of atmospheric
gas. The method includes compressing an atmospheric gas stream to
above a predetermined pressure to form at least a supercritical
atmospheric gas stream (the predetermined pressure being about the
critical pressure for the atmospheric gas stream), forming at least
a first stream from the supercritical atmospheric gas stream,
directing the first stream to a regenerator for cooling to form at
least a first cooled stream, directing the first cooled stream from
the regenerator, expanding the first cooled stream to form at least
a liquefied atmospheric gas stream, storing at least a portion of
the liquefied atmospheric gas stream as a stored liquefied
atmospheric gas, pressurizing at least a portion of the stored
liquefied atmospheric gas to above a second predetermined pressure
to form a pressurized liquefied atmospheric gas stream (the second
predetermined pressure being about the critical pressure of the
liquefied atmospheric gas), and heating at least a portion of the
pressurized liquefied atmospheric gas stream in the regenerator.
Refrigeration below the predetermined temperature is directly or
indirectly provided from an external non-combustible source to one
or more of the atmospheric gas stream, the supercritical
atmospheric gas stream, the first stream, the first cooled stream,
the liquefied atmospheric gas stream, and the pressurized liquefied
atmospheric gas stream, the predetermined temperature being about
the critical temperature of the liquefied atmospheric gas
stream.
[0009] Another aspect of the present disclosure includes a system
for periodic cooling, storing, and heating of an atmospheric gas.
The system includes a compressor configured to compress an
atmospheric gas stream to above a predetermined pressure to form at
least a supercritical atmospheric gas stream (the predetermined
pressure being about the critical pressure for the atmospheric gas
stream), a regenerator configured to receive a first stream formed
by the supercritical gas stream and to form a first cooled stream,
a pressure reducing device configured to reduce pressure of the
first cooled stream and disposed to form at least a liquefied
atmospheric gas stream, a container for storing at least a portion
of the liquefied atmospheric gas stream as stored liquefied
atmospheric gas, a pressure raising device configured to pressurize
the stored liquefied atmospheric gas to above a predetermined
pressure (the predetermined pressure being about the critical
pressure of the atmospheric gas), and a non-combustible external
refrigeration source configured to provide refrigeration below a
predetermined temperature to at least one portion of the system,
the predetermined temperature being about the critical temperature
of the liquefied atmospheric gas stream.
[0010] An advantage of the present disclosure includes greater
control and greater efficiency of heating and cooling operations in
systems for cooling and storing atmospheric gas and related
systems.
[0011] Another advantage of the present disclosure includes
permitting a sustainable periodic cycling using a regenerator,
wherein energy losses due to heat exchange are greatly reduced.
[0012] Another advantage of the present disclosure is safety due to
the use of non-combustible materials in the process.
[0013] Another advantage of the present disclosure is increased
versatility due to removal of the constraint of having to integrate
the system with a liquefied natural gas gasification unit.
[0014] Other features and advantages of the present invention will
be apparent from the following more detailed description of the
preferred embodiment, taken in conjunction with the accompanying
drawings which illustrate, by way of example, the principles of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 shows a schematic diagram of an exemplary embodiment
of a regeneration system according to the disclosure.
[0016] FIG. 2 shows a schematic diagram of an exemplary embodiment
of a regeneration system according to the disclosure.
[0017] FIG. 3 shows a schematic diagram of an exemplary embodiment
of a regeneration system according to the disclosure.
[0018] FIG. 4 shows a schematic diagram of an exemplary embodiment
of a regeneration system according to the disclosure.
[0019] FIG. 5 shows a schematic diagram of an exemplary embodiment
of a regeneration system according to the disclosure.
[0020] FIG. 6 shows a schematic diagram of an exemplary embodiment
of a regeneration system according to the disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[0021] Provided is a method and system for cooling and storing an
atmospheric gas during a first operational period of a process
cycle and heating the atmospheric gas during a second operational
period. The system and process involve a regenerator for cooling
and heating of the atmospheric gas.
[0022] Embodiments of the method and system can increase efficiency
due to the storage and subsequent use of liquid atmospheric gas,
provide heating or cooling to other operations or systems, adjust
heating and cooling operations with the system and related systems,
and/or make the process sustainable without introducing large
inefficiencies.
[0023] As used herein, the term "atmospheric gas" refers to a gas
that primarily contains nitrogen, argon, oxygen, or combinations
thereof In one embodiment, the atmospheric gas is a mixture of
nitrogen, argon, and oxygen. In one embodiment, the oxygen content
can be above about 20.95% by volume. In one embodiment, the argon
content can be above about 0.93% by volume. As used herein, the
term "regenerator" refers to a fixed body with flow features and a
heat capacity operated as a periodic heat transfer device providing
cooling when operated in a first operational mode and providing
heating in a second operational mode. As used herein, the term
"non-combustible" refers to a material that will not combust in the
presence of air.
[0024] In general, a stream flows through the flow features (for
example, flow channels) of a regenerator in a first direction
during a first operational period (for example, an off-peak demand
period when the price of electricity is generally lower) and during
the first operational mode. In the first operational mode, the
regenerator absorbs heat from at least a portion of the stream
directed into the regenerator. The absorption of heat by the
regenerator cools the stream to below a predetermined temperature
to form a stream that is directed from the regenerator. During a
second operational period (for example, an on-peak demand period
when the price of electricity is generally higher), the same
regenerator can be operated in a second operational mode. In the
second operational mode, a pressurized liquefied atmospheric gas
stream is directed through the regenerator that provides heat to
the pressurized atmospheric gas stream. The first operational
period and the second operational period can repeat multiple times
as cycles and the cycles can be repeatedly performed. The first
operational period can be during periods of lower energy demand and
the second operational period can be during periods of higher
energy demand.
[0025] As a regenerator is subject to cycles of operation during
the first operational period and the second operational period, the
ability of the regenerator to transfer or receive heat is provided
according to a temperature profile. That is, the regenerator has a
predetermined ability to transfer heat during the first operational
period and the second operational period. After a predetermined
number of cycles, the temperature profile of the regenerator of the
present disclosure has to remain substantially constant at any
fixed phase of the cycle for the process and/or system to work for
a long time. With the temperature profile being substantially
constant at fixed phases of the cycle, the temperature of the
regenerator does not substantially increase over cycles of
operational periods, so that such a process can run for months or
longer. This sustainability is provided by an external source of
refrigeration provided at a temperature below that of the critical
temperature of the atmospheric gas to at least one stream in the
process. External source of refrigeration in this disclosure is
defined by a refrigeration source being external to the streams
that are associated with the regenerator. The external source of
refrigeration can be a liquid nitrogen or liquid air stream that
comes from a source outside of the process associated with the
regenerator, the liquid atmospheric gas storage device, other
system components described herein, a refrigerator such as a gas
expander, a Sterling refrigerator, a pulse tube refrigerator, a
magnetic refrigeration, a combination thereof, etc.
[0026] A regenerator can be arranged in series with one or more
additional regenerators and/or the regenerator can be arranged in
parallel with one or more additional regenerators. Arranging the
regenerators in series can reduce longitudinal heat transfer
(longitudinal heat transfer being the heat transfer in the
direction of flow). In including a plurality of regenerators, it is
desirable that different regenerators are configured for different
values of predetermined parameters (for example, pressure ranges,
temperature ranges, and/or flow ranges).
[0027] FIG. 1 shows a schematic diagram of a regeneration system
101 for a regeneration method of heating, cooling, and storing an
atmospheric gas according to the present disclosure. In one
embodiment of the regeneration method, an atmospheric gas stream
100 is pressurized to above a predetermined pressure to form a
supercritical atmospheric gas stream 108. The predetermined
pressure is about the critical pressure for atmospheric gas within
the atmospheric gas stream 100. The atmospheric gas stream 100 is
directed through an air compressor 10. Impurities (for example,
water vapor, carbon dioxide, and/or other impurities) are removed
by an air purifier 20. Further pressurizing is achieved by a
booster compressor 30. In one embodiment, the booster compressor 30
can include intercoolers (not shown) and an aftercooler (not
shown).
[0028] As shown in FIG. 1, in one embodiment, the supercritical
atmospheric gas stream 108 is divided into a first stream 110 and a
second stream 120. The first stream 110 can be provided at a
greater volumetric flow than the second stream 120. The first
stream 110 is directed to a regenerator 40. The first stream 110
flows through the flow features (for example, flow channels) of the
regenerator 40 in a first direction during a first operational
period and during the first operational mode. In the first
operational mode, the regenerator 40 receives heat from at least a
portion of the first stream 110. This transfer of heat cools the
first stream 110 to below a predetermined temperature to form a
first cooled stream 112. The predetermined temperature is below the
critical temperature for the atmospheric gas in the atmospheric gas
stream 100. During a second operational period, the regenerator 40
is operated in a second operational mode. In the second operational
mode, a pressurized liquefied atmospheric gas stream is directed
through the regenerator 40 that provides heat to produce the
regenerator-heated atmospheric gas stream 196.
[0029] The second stream 120 (including a portion of the
supercritical atmospheric gas stream 108) is directed to an
indirect heat exchanger 50 during the first operational period. The
indirect heat exchanger 50 cools at least a portion of the second
stream 120 to form a second cooled stream 122. The combined cooled
stream 130 is further cooled by liquid air or liquid nitrogen
stream 150. In one embodiment, cooling is provided by a liquid air
or liquid nitrogen stream 150. In other embodiments, one or both of
the indirect heat exchangers 50 and 60 may be substituted with any
suitable external refrigeration source.
[0030] The indirect heat exchangers 50 and 60 can cool the
supercritical atmospheric gas stream 108, the first stream 110, the
second stream 120, the first cooled stream 112, the combined-cooled
stream 130, or a combination thereof, to form an externally cooled
stream 132. As used herein, the term "externally cooled" refers to
cooling provided from a source other than the regenerator 40. For
example, FIG. 1, shows the combined-cooled stream 130 and the
second stream 120 being cooled by external cryogenic stream 150
(which can provide refrigeration to both heat changers 50, 60).
Additionally or alternatively, cooling can be provided by expanding
a high pressure gas stream (not shown) to a temperature below the
critical temperature for the atmospheric gas. Referring to FIG. 6,
in-line cooling to form the externally cooled stream 132 can be
provided by cooling the supercritical atmospheric gas stream 108,
the first stream 110, the first cooled stream 112, or a combination
thereof. Specifically, FIG. 6 shows the first cooled stream 112
being cooled by the external refrigeration source 500 to form the
externally cooled stream 130. In this embodiment, the external
refrigeration source 500 can be a Sterling refrigerator, a
Gifford-McMahon refrigerator, a pulse tube refrigerator, a
thermoacoustic refrigerator, a magnetic refrigerator, a combination
thereof, or any other suitable refrigeration source.
[0031] During the first operational period, the first cooled stream
112 and the second cooled stream 122 are arranged to be directed to
form the combined-cooled stream 130. The combined-cooled stream 130
is further-cooled by a liquid air or liquid nitrogen stream 150
(which is an external source of refrigeration here) in a second
indirect heat exchanger 60. The second indirect heat exchanger 60
is configured for a lower temperature than the first indirect heat
exchanger 50. The liquid air or liquid nitrogen stream 150 can be
provided at a predetermined pressure (for example, above ambient
atmospheric pressure). Upon being cooled, the combined-cooled
stream 130 forms a further-cooled stream 132. The further-cooled
stream 132 is expanded to form a liquefied atmospheric gas stream
134, which is stored at a lower pressure in air storage tank 80
(for example, slightly above ambient atmospheric pressure). In one
embodiment, the cooled stream 132 is expanded by an expansion valve
70. In an alternate embodiment, as shown in FIG. 3, the cooled
stream 132 can be expanded by a dense fluid expander 370. In the
alternate embodiment, the liquid air or liquid nitrogen stream 150
(a source of external refrigeration in this process) can be heated
in the indirect heat exchanger 60 and then heated in the indirect
heat exchanger 50.
[0032] During the second operational period (illustrated by the
dashed/dotted-line portions of FIG. 1), a liquid atmospheric gas
stream 190 is directed from the air storage tank 80 and pressurized
by a pressure increasing mechanism 90 (for example, a pump) to form
a pressurized liquid atmospheric gas stream 194. The pressurized
liquid atmospheric gas stream 194 is directed to the regenerator 40
and is heated to about ambient temperature or slightly above
ambient temperature. In one embodiment, the pressure of the liquid
air is lower (for example, by about 5-50 psi) than the first stream
110 of the atmospheric gas directed into the regenerator 40.
[0033] Other suitable sources of cooling may additionally or
alternatively be used. For example, external sources may provide
additional streams that are below the critical temperature of the
atmospheric gas and are blended with the first cooled stream 112,
the second cooled stream 122, the liquid air or liquid nitrogen
stream 150, the combined cooled stream 130, the further-cooled
stream 132, the liquefied atmospheric gas stream 134, the liquid
atmospheric gas stream 190, and/or the pressurized liquid
atmospheric gas stream 194. In one embodiment, additional or
alternative cooling is provided from one or more regenerators. The
external refrigeration permits cooling below the critical
temperature of the atmospheric gas, thereby extending the
operational duration of the regeneration system. For example,
including the external refrigeration can extend operational
sustainability by a duration of months or years. Introducing liquid
nitrogen, liquid air, and/or adding a cryogenic refrigerator into
the process can provide such external refrigeration. The cooling in
the regeneration system is performed using non-combustible
materials. For example, fluids used in cooling of the refrigeration
system are non-combustible. As used herein, the term
"non-combustible fluid" can include air, argon, nitrogen, oxygen,
helium, xenon, and combinations thereof.
[0034] FIG. 2 shows a schematic diagram of regeneration system 101
according to a further embodiment of the disclosure. As in the
embodiment shown in FIG. 1, supercritical atmospheric gas stream
108 is divided into a first stream 110 and a second stream 120. In
this embodiment, a supercritical atmospheric gas stream 202 (a
portion of the second stream 120 that is cooled to a predetermined
temperature such as about -50.degree. F. to about -180.degree. F.
is directed from within the indirect heat exchanger 50 to an
expander 210. An exhaust stream 203 (which may be a two-phase
stream) is directed from the indirect heat exchanger 50 to a phase
separator 230. The phase separator 230 directs a vapor stream 204
to the indirect heat exchanger 50. The indirect heat exchanger 50
transfers heat to the vapor stream 204 to form a heated atmospheric
gas stream 205. The heated atmospheric gas stream 205 is at an
increased temperature (for example, about ambient temperature) and
a predetermined pressure (for example, above about 90 psia). The
heated atmospheric gas stream 205 can be recycled to the inlet of
the booster compressor 30 or for other purposes such as for feeding
to a cryogenic air separation unit.
[0035] In addition to the first stream 110 and the second stream
120, the supercritical atmospheric gas stream 108 can be divided
into the third stream 206, which can be smaller than the first
stream 110 and the second stream 120. The third stream 206 is
directed to a second expander 220. The second expander 220 can be
configured for a higher temperature than expander 210 and can
substantially balance heat supply with heat absorption at a
plurality of temperatures in the indirect heat exchanger 50. The
second expander 220 expands the third stream 206 to form an
expander exhaust stream 208. The expander exhaust stream 208 is
directed to the indirect heat exchanger 50 to combine with vapor
stream 204 after it is partially heated within the indirect heat
exchanger 50, thereby forming heated atmospheric gas stream 205
upon further heating in the heat exchanger 50. The heated
atmospheric gas stream 205 is at about ambient temperature. The
heated atmospheric gas stream 205 is recycled to the inlet of the
booster compressor 30.
[0036] In the embodiment shown in FIG. 2, the first cooled stream
112 is expanded by a dense fluid expander 270, and the second
cooled stream 122 is expanded by a throttle valve 240. Here, the
exhaust of the first expander 210 (for example, stream 203) and
that of the first expander 210 (for example, stream 208) provide
external refrigeration to the system. Among them, the colder
portion of the refrigeration provided by the exhaust of the first
expander (for example, stream 203) is below the critical
temperature of the atmospheric gas streams being cooled (streams
110 and 120). The first cooled stream 112, the second cooled stream
122, and the exhaust stream 203 directed from the indirect heat
exchanger 50 are combined and directed to the phase separator 230
to form a liquid stream 232 and a vapor stream 204. The liquid
stream 232 is directed from the phase separator 230, further
expanded by a throttle valve 260, and directed to a second phase
separator 250. The second phase separator 250 operates at a lower
pressure than the first phase separator 230. The second phase
separator 250 forms a nitrogen-rich vapor stream 234 that is
directed to the indirect heat exchanger 50. In the indirect heat
exchanger 50, the nitrogen-rich vapor stream 234 receives heat from
second stream 120 and forms a second nitrogen-rich vapor stream
236. The second nitrogen-rich vapor stream 236 is vented or
directed to further processes. Liquid from the second phase
separator 250 forms the liquefied atmospheric gas stream 134 and is
directed to the liquid air atmospheric gas storage tank 80.
[0037] FIG. 3 shows a schematic diagram of the regeneration system
101 according to another embodiment of the disclosure. In this
embodiment, a regenerator-heated atmospheric gas stream 196
(including atmospheric gas) is directed from the regenerator 40 to
a heat exchanger 310 to form a heated stream 396. The heat
exchanger 310 transfers heat from an exhaust stream 302 of a gas
turbine (not shown) to the regenerator-heated atmospheric gas
stream 196. The gas turbine can be used for generating electricity
during the second operational period (peak operation). The heated
stream 396 is directed to an expander 320 to form an expanded
stream 398 and to generate power. In one embodiment, operation of
the system 101 includes directing streams having approximately the
compositions listed in Table 1.
TABLE-US-00001 TABLE 1 Composition (mol %) Stream N.sub.2 Ar
O.sub.2 CO.sub.2 H.sub.2O P(psia) T(F.) Flow(lbmol/h) 100 .7812
.0093 .2095 0 0 14.69 90 6500 110 .7812 .0093 .2095 0 0 849 100
6402.5 120 .7812 .0093 .2095 0 0 849 100 97.5 112 .7812 .0093 .2095
0 0 845 -311.5 6402.5 132 .7812 .0093 .2095 0 0 844 -317.5 6500 134
.7812 .0093 .2095 0 0 15 -317.5 6500 150 1 0 0 0 0 15.5 -319.6 228
154 1 0 0 0 0 15 -29.0 6500 194 .7812 .0093 .2095 0 0 845 -312.29
6500 196 .7812 .0093 .2095 0 0 845 -312.29 6500 396 .7812 .0093
.2095 0 0 840 88.15 6500 398 .7812 .0093 .2095 0 0 14.7 97.44 6500
302 .74756 .00890 .11435 .04306 .08612 15 900 6689.3 304 .74756
.00890 .11435 .04306 .08612 14.7 165.7 6689.3
[0038] In this embodiment, work by the air compressor 10 and
booster compressor 30 can be about 11,903 kW, work by the expander
320 can be about -10006 kW, and work by the dense fluid expander
370 can be about -88 kW. In this embodiment, the flow conditions,
work inputs, and/or work outputs are based on the same flow
duration the first operational period (off-peak operation) and the
second operational period (peak operation). In other embodiments,
the duration of the first operational period and the duration of
the second operational period differ. For example, the first
operational period (off-peak operation) can be 10 hours while the
second operational period (peak operation) can be 6 hours. In this
embodiment, the flow amounts of the streams 100, 110, 120, 112, and
132 during the first operational period, or a flow amount of
streams 150, 154, 194, 196, 396, 398, 302, and 304 and an amount of
work of the expander 320 and/or the dense fluid expander 370 during
the second operational period can be adjusted. For example, the
adjustment can include reducing the flow amounts of the streams
100, 110, 120, 112, and 132 by multiplying by a factor of 0.6 and
reducing the amount of work of the air compressor 10 by multiplying
by the same factor. In this embodiment, the flow amount of liquid
nitrogen in stream 150 can be about 3.5% of the flow amount of the
regenerator-heated atmospheric gas stream 196.
[0039] In one embodiment, the expanded stream 398 directed from the
expander 320 is directed to an air separation system (not shown).
In another embodiment, the expanded stream 398 is directed to a
data center 610 as a source of cooling. For example, computers in a
data center may be maintained by air of a predetermined temperature
and/or a predetermined relatively low humidity. In one embodiment,
in conjunction with the operating conditions described with
reference to FIG. 3, expanded stream 398 is within a predetermined
temperature range. The expanded stream 398 can be blended with air
to form a stream with a desired temperature and/or a desired
humidity. This use of the expanded stream 398 in the data center
610 can reduce or eliminate the need for refrigeration during the
peak electricity demand hours.
[0040] FIG. 4 shows a schematic diagram of the regeneration system
101 according to one embodiment of the disclosure. In this
embodiment, the regenerator-heated atmospheric gas stream 196 is
directed from the regenerator 40 to a heat exchanger 50 of a
cryogenic air separation plant (not shown). The heat exchanger 50
is a "pumped LOX heat exchanger" which can be used to heat a pumped
liquid oxygen from a cryogenic air separation plant. The heat
exchanger 50 transfers heat from the regenerator-heated atmospheric
gas stream 196 to a liquid oxygen stream 504 directed to the heat
exchanger 50. Upon being heated, the liquid oxygen stream 504 forms
a gaseous or supercritical oxygen stream 506, which is sent to an
oxygen consuming process. Upon being the cooled, regenerator-heated
atmospheric gas stream 196 forms a cooled stream 502 and is used in
a cryogenic air separation plant.
[0041] FIG. 5 shows a schematic diagram of the regeneration system
101 according to another embodiment of the disclosure. In this
embodiment, the regenerator-heated atmospheric gas stream 196
directed from the regenerator 40 is heated by an exhaust gas stream
712 of a gas turbine in a heat exchanger 710. The exhaust gas
stream 712 forms a cooled stream 714, which can be vented or used
in another process. The regenerator-heated atmospheric gas stream
196 forms a heated stream 702 that is directed to the expander 720
forming an expanded stream 704 which forms at least a part of a
feed stream 705. The feed stream 705 can be directed to a gas
turbine compressor 730 after injection of a water stream 706 to
further cool atmospheric gas in the gas turbine compressor 730 (for
example, by evaporative cooling), thereby forming a compressed
air-like stream 708 that is sent to the combustor (not shown) of
the gas turbine (not shown). In one embodiment, the feed stream 705
is directed to an air separation system (not shown).
[0042] While the invention has been described with reference to a
preferred embodiment, it will be understood by those skilled in the
art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the invention. In addition, many modifications may be made to
adapt a particular situation or material to the teachings of the
invention without departing from the essential scope thereof
Therefore, it is intended that the invention not be limited to the
particular embodiment disclosed as the best mode contemplated for
carrying out this invention, but that the invention will include
all embodiments falling within the scope of the appended
claims.
* * * * *