U.S. patent application number 14/084193 was filed with the patent office on 2014-03-20 for self cooling heat exchanger.
This patent application is currently assigned to UOP LLC. The applicant listed for this patent is UOP LLC. Invention is credited to Phillip F. Daly, Kurt M. Vanden Bussche.
Application Number | 20140076528 14/084193 |
Document ID | / |
Family ID | 43305396 |
Filed Date | 2014-03-20 |
United States Patent
Application |
20140076528 |
Kind Code |
A1 |
Daly; Phillip F. ; et
al. |
March 20, 2014 |
SELF COOLING HEAT EXCHANGER
Abstract
An inexpensive heat exchanger is disclosed, wherein the heat
exchanger is made up of a plurality of plates and each plate has at
least one channel defined in the plate. The plates are stacked and
bonded together to form a block having conduits for carrying at
least one fluid and where the exchanger includes an expansion
device enclosed within the unit.
Inventors: |
Daly; Phillip F.; (Palatine,
IL) ; Vanden Bussche; Kurt M.; (Lake in the Hills,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UOP LLC |
Des Plaines |
IL |
US |
|
|
Assignee: |
UOP LLC
Des Plaines
IL
|
Family ID: |
43305396 |
Appl. No.: |
14/084193 |
Filed: |
November 19, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12485284 |
Jun 16, 2009 |
8631858 |
|
|
14084193 |
|
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|
Current U.S.
Class: |
165/166 |
Current CPC
Class: |
F25J 5/002 20130101;
F25J 1/0262 20130101; H05K 7/20272 20130101; F25J 1/0022 20130101;
F28F 13/06 20130101; F03B 13/00 20130101; F25J 2290/44 20130101;
F28F 3/12 20130101; F25J 2240/30 20130101; F25J 1/0057 20130101;
H05K 7/20327 20130101; F28D 9/005 20130101; F28D 2021/0033
20130101; F05B 2220/602 20130101; Y02B 10/50 20130101; F05B 2250/82
20130101; F25J 1/0052 20130101 |
Class at
Publication: |
165/166 |
International
Class: |
F28F 3/12 20060101
F28F003/12 |
Claims
1. A heat exchanger comprising: at least one plate having a first
channel defined therein having an inlet and an outlet, and a second
channel defined therein having an inlet and an outlet, wherein the
first and second channels are in fluid isolation; an expansion
device disposed within the first channel; a cover plate; a
plurality of plates, wherein each plate has a first channel defined
therein having an inlet and an outlet, and a second channel defined
therein having an inlet and an outlet, wherein the first and second
channels are in fluid isolation; an expansion device disposed
within the first channel; and at least one manifold having a first
inlet channel in fluid communication with each first channel inlet,
the at least one manifold having a first outlet channel in fluid
communication with the each first channel outlet, the at least one
manifold having a second inlet channel in fluid communication with
each second channel inlet and the at least one manifold having a
second outlet channel in fluid communication with each second
channel outlet.
2. A heat exchanger comprising: at least one first plate having a
first channel defined therein having an inlet and an outlet,
wherein the first channel has a first section, a second section,
and a third section; an expansion device disposed within the second
section; and a cover plate.
3. The heat exchanger of claim 2 further comprising: a second
channel defined in the at least one plate having an inlet and an
outlet.
4. The heat exchanger of claim 2 further comprising: at least one
second plate having a second channel defined therein having an
inlet and an outlet, wherein the first plate and second plate each
have an upper face where the channel is defined in the upper face,
and a lower face, and where the second plate is arranged such that
the lower face of a first plate is in sealing contact with the
upper face of a second plate, and the second channel is
substantially parallel to the third section of the first
channel.
5. The heat exchanger of claim 4 further comprising: a plurality of
first plates; a plurality of second plates, wherein the first and
second plates are stacked in an alternating sequence; and at least
one manifold having a first inlet channel in fluid communication
with each first channel inlet, the at least one manifold having a
first outlet channel in fluid communication with each first channel
outlet, the at least one manifold having a second inlet channel in
fluid communication with each second channel inlet and the at least
one manifold having a second outlet channel in fluid communication
with each second channel outlet.
6. The heat exchanger of claim 4 further comprising: a plurality of
first plates; a plurality of second plates, wherein the first and
second plates are stacked in an alternating sequence; and wherein
the cover plate further includes a first channel inlet port in
fluid communication with each first channel inlet, a first channel
outlet port in fluid communication with the each first channel
outlet, a second channel inlet port in fluid communication with
each second channel inlet and a second channel outlet port in fluid
communication with each second channel outlet.
7. A heat exchanger comprising: at least one first plate having a
first channel defined therein having an inlet and an outlet; at
least one second plate having a first channel defined therein
having an inlet in fluid communication with the first plate first
channel outlet and an outlet; an expansion device disposed within
the first channel.
8. The heat exchanger of claim 7 further comprising a second
channel defined in the at least one second plate and having an
inlet and an outlet.
9. The heat exchanger of claim 7 further comprising a cover plate
having a first channel inlet port in fluid communication with each
first channel inlet, and a first channel outlet port in fluid
communication with each second plate first channel outlet.
10. The heat exchanger of claim 9 further comprising a second
channel inlet port in the cover plate in fluid communication with
the second channel inlet and a second channel outlet port in the
cover plate in fluid communication with the second channel
outlet.
11. The heat exchanger of claim 10 wherein each of the inlet ports
and outlets pass through the plates to be in fluid communication
with the corresponding cover plate port.
12. The apparatus of claim 8 further comprising at least one
manifold having a first inlet channel in fluid communication with
each first channel inlet, the at least one manifold having a first
outlet channel in fluid communication with the each first channel
outlet, the at least one manifold having a second inlet channel in
fluid communication with each second channel inlet and the at least
one manifold having a second outlet channel in fluid communication
with each second channel outlet.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a Division of prior copending
application Ser. No. 12/485,284 which was filed Jun. 16, 2009, the
contents of which are incorporated herein by reference thereto.
FIELD OF THE INVENTION
[0002] The present invention relates to the cooling of fluids
through the self-cooling from the fluid. More particularly this
invention goes to the cooling of a fluid to self-cool the fluid and
to cool and, potentially, liquefy another fluid.
BACKGROUND OF THE INVENTION
[0003] The demands for natural gas have increased in recent years.
The transport of natural gas is through pipelines or through the
transportation on ships. Many areas where natural gas is located
are remote in the sense that there are no convenient pipelines to
readily transfer the natural gas to the market. Therefore natural
gas is frequently transported by ship. The transport of natural gas
on ships requires a means to reduce the volume and one method of
reducing the volume is to liquefy the natural gas. The process of
liquefaction requires cooling the gas to very low temperatures.
There are several known methods of liquefying natural gas as can be
found in U.S. Pat. No. 6,367,286; U.S. Pat. No. 6,564,578; U.S.
Pat. No. 6,742,358; U.S. Pat. No. 6,763,680; and U.S. Pat. No.
6,886,362.
[0004] One of the methods is a cascade method using a number of
shell and tube heat exchangers. Each of these shell and tube heat
exchangers is very large and very expensive, and presents problems
of economics and feasibility for remote and smaller natural gas
fields. It would be desirable to have a device for liquefying
natural gas that is compact and relatively inexpensive to ship and
use in remote locations, especially for natural gas fields found
under the ocean floor, where collection and liquefaction of the
natural gas can be performed on board a floating platform using a
compact unit.
[0005] There is also an increasing demand for methods of cooling
gases to condense them for transport or for separation
purposes.
BRIEF SUMMARY OF THE INVENTION
[0006] The present invention comprises a heat exchanger made up of
one or more plates where each plate has at least one channel
etched, or milled, or otherwise formed in the plate. The channels
each have an inlet and an outlet for admitting and withdrawing a
cooling fluid, or refrigerant. The channels each have an expansion
device positioned within the channel, where the cooling fluid is
expanded and provides self-cooling for the cooling fluid. The
plates in the heat exchanger are bonded to form a cooling block,
and can be used as a heat sink for devices external to the heat
exchanger. In one embodiment, the heat exchanger can provide
cooling for a second fluid where the plate includes a second
channel formed in the plate. The second channel includes a second
inlet and outlet for admitting and withdrawing a cooled fluid. The
positioning of the expansion device provides for improved
efficiency in the heat exchanger by allowing a better flow
distribution of the refrigerant in the channels.
[0007] Other objects, advantages and applications of the present
invention will become apparent to those skilled in the art from the
following detailed description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic of a first embodiment of the heat
exchanger;
[0009] FIG. 2 is a schematic of a second embodiment of the heat
exchanger wherein the fluids enter and leave through an edge of the
plates;
[0010] FIG. 3 is a schematic of the heat exchanger for self-cooling
a fluid or for use as a heat sink design; and
[0011] FIG. 4 is a schematic of the heat exchanger wherein the
cooled fluid passes through a separate plate from the cooling
fluid.
DETAILED DESCRIPTION OF THE INVENTION
[0012] The use of liquefied natural gas (LNG) is increasing, as
fuel and a means of transporting natural gas from remote sites
having natural gas, without a nearby gas pipeline, to more distant
areas where the natural gas is consumed. Natural gas is typically
recovered from gas wells that have been drilled and is in the gas
phase at high pressure. The high pressure gas is then treated and
passed to a pipeline for transport. However, there are an
increasing number of natural gas fields that are in remote
locations relative to natural gas pipelines. The present invention
is directed to a heat exchanger for cooling the natural gas at the
gas wells. By providing an inexpensive heat exchanger for cooling
and liquefying natural gas in remote locations, natural gas can be
recovered on site and transported as LNG, rather than requiring a
natural gas pipeline, or transporting the gas at very high
pressures. In addition, the present invention can be used as a
means for cooling other materials, such as providing for a cooling
device to cool electronics or other devices that generate heat and
need external cooling.
[0013] In a first embodiment, the invention comprises a heat
exchanger that is fabricated from plates that are bonded together
to form an integral unit. The plates have channels etched, milled,
pressed, stamped, inflated, or by other methods known in the art,
into them for the transport of coolant and fluid to be cooled. When
the plates are bonded together, the channels are covered and form
conduits through which fluids can flow. The bonding method will
depend on the materials of construction, such as with aluminum
plates, bonding involves brazing the aluminum plates together. With
steel, diffusion bonding or welding can be performed to bond the
steel plates together. Other means of bonding plates are known to
those skilled in the art.
[0014] The most common commercial design of a heat exchanger for
the cooling of natural gas is a spiral wound heat exchanger where
the coolant cascades within a shell over spiral wound tubes
carrying the gas to be cooled. Benefits of the present design over
the spiral wound design include lower cost, lower weight, and a
more compact structure as well as improved heat transfer
characteristics under conditions of motion, as are expected when
the heat exchanger is used on board a floating platform or
vessel.
[0015] As shown in FIG. 1, the heat exchanger comprises at least
one plate 10 having a first channel 12 defined therein. The first
channel 12 has an inlet 14 and an outlet 16. The plate 10 also has
a second channel 22 defined therein, where the second channel 22
has an inlet 24 and an outlet 26 with the first 12 and second 22
channels in fluid isolation. The first channel 12 includes an
expansion device 20 disposed within the channel 12. The heat
exchanger further includes a cover plate 30. The cover plate 30 has
a first channel inlet port 34 in fluid communication with the first
channel inlet 14, and a first channel outlet port 36 in fluid
communication with the first channel outlet 16. The cover plate 30
also includes a second channel inlet port 38 in fluid communication
with the second channel inlet 24, and a second channel outlet port
42 in fluid communication with the second channel outlet 26.
[0016] The heat exchanger can comprise a plurality of first plates
10, where the plates 10 are stacked and bonded together. The inlets
14 for the first channels 12 are all in fluid communication with
the cover plate first channel inlet port 34, and the outlets 16 for
the first channels 12 are all in fluid communication with the cover
plate first channel outlet port 36. Similarly, the inlets 24 for
the second channels 22 are all in fluid communication with the
cover plate second channel inlet port 38, and the outlets 26 for
the second channels 22 are all in fluid communication with the
cover plate second channel outlet port 42. One method for this
fluid communication is for each of the inlets 14, 24 and each of
the outlets 16, 26 to pass through the plates 10 and be aligned
when the plates 10 are stacked and bonded. The inlets 14, 24 and
the outlets 16, 26 on the bottom most plate of the stack would be
the only inlets and outlets that do not pass through the last plate
in the heat exchanger stack.
[0017] The positioning of the expansion device 20 within the
channel provides better flow distribution of the cooling fluid. The
flow is completely contained within the heat exchanger, which is of
particular importance when the cooling fluid provides for two phase
flow after expansion and multiple channels or plates in parallel.
Conventionally, the expanded fluid is passed to a chamber, where
the liquid can separate from the vapor, upon which liquid and vapor
are separately re-introduced into the channel. The present
invention avoids this separation, overcoming the inefficiencies
associated with uneven distribution of the gas and liquid during
re-introduction. This advantage is particularly prominent in cases
where the device is operating while in motion, as on board a ship,
as the separation of gas and liquid in a chamber becomes more
difficult to accomplish under those conditions. In addition, no
header is needed and no additional equipment is added outside the
heat exchanger. An additional advantage is the removal of the need
for a pressure test, as is required with an expansion device
outside of the heat exchanger. Furthermore, in cases where the heat
exchanger is used in cryogenic service, the absence of external
welds may avoid the need for a nitrogen sweep of the cold box in
which the heat exchanger is disposed, further reducing the cost of
the operation.
[0018] The expansion device 20 can be chosen according to the
proposed design purpose of the heat exchanger, and according to the
cooling fluid, or coolant, selected. In one embodiment, the
expansion device 20 comprises a restriction in the channel 12 to
produce a desired pressure drop and allow the fluid to expand, or
flash. Another expansion device 20 includes a Joule-Thomson valve.
One example of a Joule-Thomson valve is a conically shaped valve
that fits onto a circular seat. The valve is positioned in the
channel such that when opened, a gap is created between the conical
section and the circular seat. Control of the amount of expansion
is regulated by the size of the gap created in opening the valve.
For the embodiment comprising multiple plates, the Joule Thomson
valve can comprise multiple valves linked through a common drive
shaft for closing and opening the valves.
[0019] In another embodiment, the expansion device 20 comprises a
micro-turbine. The micro-turbine can be used to recover energy from
the expansion of the cooling fluid. The amount of energy recovered,
or conversely, the level of expansion attained, can be controlled
by means of variable resistance applied to the drive shaft of the
turbine, such that the device operates according to the cooling
demand required.
[0020] In a second embodiment, as shown in FIG. 2, the heat
exchanger includes at least one plate 10 having a first channel 12
defined therein. The first channel 12 includes an inlet 14 and an
outlet 16, and an expansion device 20 disposed within the first
channel 12. The heat exchanger includes a cover plate 30 which
encloses the channels 12 to form covered channels. The heat
exchanger can also include a second channel 22 disposed therein.
The second channel 22 includes an inlet 24 and an outlet 26, and is
in fluid isolation from the first channel 12. In the second
embodiment, the inlets 14, 24 and outlets 16, 26 are positioned at
an edge of the plate 10. The positioning allows for the use of a
manifold to connect the inlets 14 of the plurality of first channel
inlets 14 with a single distribution channel in the manifold.
Likewise, this is done for the outlets 16 of the first channel 12,
and the inlets 24 and outlets 26 of the second channels 22. The
first channel inlets 14 are in fluid communication with a manifold
first inlet channel, the first channel outlets 16 are in fluid
communication with a manifold first outlet channel, the second
channel inlets 24 are in fluid communication with a manifold second
inlet channel, and the second channel outlets 26 are in fluid
communication with a manifold second outlet channel. An alternate
design includes multiple manifolds, especially where the inlets and
outlets of a channel are on different edges of the plate 10. An
individual manifold with multiple channels can be used, or multiple
manifolds with one or more channels in each manifold can be
used.
[0021] In one embodiment, the heat exchanger can be used to provide
a self-cooling heat sink, where the heat exchanger is cooled and
provides conductive heat transfer through its external surfaces,
for the cooling of items such as electrical, or electronic,
equipment, or external surfaces of reactors. In this embodiment,
the exchanger, as shown in FIG. 3, comprises at least one plate 10
wherein a first channel 12 is defined, and a cover plate. The
channel 12 has an inlet 14 and an outlet 16, and has three
sections: a first section, a second section, and a third section,
with an expansion device 20 disposed within the second section. A
coolant, or refrigerant, is passed into the channel 12 through the
inlet 14, expanded through the expansion device 20, thereby
generating a cooled refrigerant. The refrigerant then passes
through the third section of the channel 12, cools the heat
exchanger, and passes out of the channel 12 through the outlet 16.
A plurality of the plates 10 can be stacked and bonded together to
form a single device which presents a flat cooling surface for
contact cooling. The heat exchanger can include a manifold having a
manifold inlet channel in fluid communication with the inlets 12,
and for delivering the coolant to the heat exchanger. The manifold
has a manifold outlet channel in fluid communication with the
outlets 16 and collects the expanded coolant. In an alternate
embodiment of the multiple first plate embodiment, the heat
exchanger can include a second channel in the first plate 10 for
carrying a fluid to be cooled. Alternatively, there can be separate
manifolds for each plurality of first channel inlets 14, each
plurality of first channel outlets 16, each plurality of second
channel inlets 24, and each plurality of second channel outlets 26.
The separate manifolds provide flexibility and convenience for
differing designs.
[0022] In an alternate embodiment, the design includes at least one
first plate and at least one second plate. The first plate includes
a first channel defined therein for carrying the coolant. The
second plate includes a continuation of the first channel defined
therein from the first plate, with an expansion device disposed
within the first channel. The coolant then enters the first channel
in the first plate, and is expanded and flows through the first
channel in the second plate. The first channel in the second plate
can follow a substantially parallel path to the first channel in
the first plate providing self-cooling of the fluid, and the
expansion device can be positioned in the first plate, the second
plate, or at the juncture where the coolant flows from the first
plate to the second plate. In addition, the second plate can
include a second channel defined therein. The second channel can
carry a fluid to be cooled. This variation provides for flexibility
of design for manufacturing convenience.
[0023] One embodiment provides for at least one second plate 40, as
shown in FIG. 4. The heat exchanger includes at least one first
plate 10 as described above, having a first channel 12 defined
therein and an expansion device 20 disposed within the first
channel 12. The second plate 40 has a second channel 42 defined
therein, and having an inlet 44 and an outlet 46. The first 10 and
second 40 plates are arranged in an alternating sequence to form a
stack of first plate 10, second plate 40, first plate 10, second
plate 40, etc., and the plates are bonded together with a cover
plate 30 to form a single unit. The heat exchanger can include a
manifold having a first inlet channel in fluid communication with
the plurality of first channel inlets 14, a first outlet channel in
fluid communication with the plurality of first channel outlets 16,
a second inlet channel in fluid communication with the plurality of
second channel inlets 44, and a second outlet channel in fluid
communication with the plurality of second channel outlets 46.
[0024] The design and arrangement of the channels 12, 42, as with
the other embodiments can be chosen to maximize heat transfer area
between channels. This includes channels having a sinuous path, or
other path design. Variations can include multiple manifolds for
the distribution and collection of the coolant and fluid to be
cooled.
[0025] Several embodiments have been described and it is not
intended that the invention be limited to those described, but that
the invention is intended to cover variations in channel paths,
channel designs, and other features that provide increased heat
transfer area, and optimization of heat transfer between a cooling
fluid channel and a fluid to be cooled channel.
[0026] While the invention has been described with what are
presently considered the preferred embodiments, it is to be
understood that the invention is not limited to the disclosed
embodiments, but it is intended to cover various modifications and
equivalent arrangements included within the scope of the appended
claims.
* * * * *