U.S. patent application number 13/562739 was filed with the patent office on 2013-11-21 for cng delivery system with cryocooler and method of supplying purified cng.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. The applicant listed for this patent is Guillaume Becquin, Chiranjeev Kalra, Evangelos Trifon Laskaris, Anna Lis Laursen, John Brian McDermott, Ernst Wolfgang Stautner, Tao Zhang, Jalal Hunain Zia. Invention is credited to Guillaume Becquin, Chiranjeev Kalra, Evangelos Trifon Laskaris, Anna Lis Laursen, John Brian McDermott, Ernst Wolfgang Stautner, Tao Zhang, Jalal Hunain Zia.
Application Number | 20130305744 13/562739 |
Document ID | / |
Family ID | 49580155 |
Filed Date | 2013-11-21 |
United States Patent
Application |
20130305744 |
Kind Code |
A1 |
Laursen; Anna Lis ; et
al. |
November 21, 2013 |
CNG DELIVERY SYSTEM WITH CRYOCOOLER AND METHOD OF SUPPLYING
PURIFIED CNG
Abstract
A fuel gas delivery system is provided. The fuel gas delivery
system includes a feed line configured to provide a natural gas
stream and a cryocooler fluidly coupled to the feed line. The
cryocooler is configured to condense the natural gas to provide a
liquefied natural gas (LNG) stream and to freeze impurities
contained in the natural gas stream. The frozen impurities are
separated from said LNG stream. A first heat exchanger is fluidly
coupled to the cryocooler and the first heat exchanger is
configured to vaporize at least a portion of the LNG stream to
provide compressed natural gas. A delivery line is configured to
supply the compressed natural gas to an end user and a removal line
is configured to remove the impurities from the fuel gas delivery
system.
Inventors: |
Laursen; Anna Lis; (Clifton
Park, NY) ; Laskaris; Evangelos Trifon; (Schenectady,
NY) ; Stautner; Ernst Wolfgang; (Niskayuna, NY)
; Zia; Jalal Hunain; (Niskayuna, NY) ; Kalra;
Chiranjeev; (Glenville, NY) ; McDermott; John
Brian; (Rexford, NY) ; Zhang; Tao; (Clifton
Park, NY) ; Becquin; Guillaume; (Munich, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Laursen; Anna Lis
Laskaris; Evangelos Trifon
Stautner; Ernst Wolfgang
Zia; Jalal Hunain
Kalra; Chiranjeev
McDermott; John Brian
Zhang; Tao
Becquin; Guillaume |
Clifton Park
Schenectady
Niskayuna
Niskayuna
Glenville
Rexford
Clifton Park
Munich |
NY
NY
NY
NY
NY
NY
NY |
US
US
US
US
US
US
US
DE |
|
|
Assignee: |
GENERAL ELECTRIC COMPANY
Schenectady
NY
|
Family ID: |
49580155 |
Appl. No.: |
13/562739 |
Filed: |
July 31, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61649672 |
May 21, 2012 |
|
|
|
Current U.S.
Class: |
62/6 |
Current CPC
Class: |
B01D 5/006 20130101;
F17C 2223/0123 20130101; F17C 2221/033 20130101; F17C 2225/036
20130101; F17C 2205/0326 20130101; F17C 2270/07 20130101; F17C
2227/0135 20130101; F17C 2227/047 20130101; F17C 2221/032 20130101;
F17C 2265/015 20130101; F17C 2227/0365 20130101; F17C 2227/0369
20130101; F17C 2227/0353 20130101; F17C 2265/065 20130101; F17C
2227/0346 20130101; F17C 9/00 20130101; F17C 5/06 20130101; F17C
2260/056 20130101; F17C 2250/01 20130101; F17C 2250/043 20130101;
F17C 2221/012 20130101; F17C 2227/0393 20130101; Y02E 60/321
20130101; F17C 2225/0123 20130101; F17C 2227/0304 20130101; F17C
2270/0139 20130101; B01D 7/02 20130101; F17C 5/007 20130101; F17C
2223/033 20130101; F17C 2227/0327 20130101; F17C 2227/0339
20130101; F17C 2227/0311 20130101; F17C 2250/0426 20130101; Y02E
60/32 20130101; F17C 2227/0306 20130101 |
Class at
Publication: |
62/6 |
International
Class: |
F25B 9/00 20060101
F25B009/00 |
Claims
1. A fuel gas delivery system is disclosed comprising: a feed line
configured to provide a natural gas stream; a cryocooler fluidly
coupled to said feed line, said cryocooler configured to condense
the natural gas to provide a liquefied natural gas (LNG) stream and
to freeze impurities contained in the natural gas stream, wherein
the frozen impurities are separated from the LNG stream; a first
heat exchanger fluidly coupled to said cryocooler, said first heat
exchanger configured to vaporize at least a portion of the LNG
stream to provide compressed natural gas; a delivery line
configured to supply the compressed natural gas to an end user; and
a removal line configured to remove the frozen impurities from said
fuel gas delivery system.
2. The fuel gas delivery system of claim 1, wherein said system is
configured to remove the frozen impurities during a regeneration
mode, wherein during the regeneration mode, said system is
depressurized and/or warmed to warm the impurities to at least one
of a gas and a liquid for delivery to the removal line.
3. The fuel gas delivery system of claim 1, further comprising a
buffer tank fluidly coupled to said delivery line, wherein said
buffer tank is configured to store the compressed natural gas at a
pressure higher than a dispensing pressure and to supply compressed
natural gas at said dispensing pressure.
4. The fuel gas delivery system of claim 1, further comprising a
regenerator fluidly coupled to said feed line and said delivery
line, wherein said regenerator is configured to provide heat
exchange between the natural gas stream and the LNG stream.
5. The fuel gas delivery system of claim 4, further comprising a
pump fluidly connected between said cryocooler and said
regenerator, said pump configured to increase the LNG stream to a
predetermined pressure.
6. The fuel gas delivery system of claim 1, further comprising a
first storage tank fluidly coupled to said cryocooler and
configured to store LNG from said cryocooler.
7. The fuel gas delivery system of claim 6, wherein said heat
exchanger is thermally coupled to said first storage tank and
configured to vaporize LNG within said first storage tank.
8. The fuel gas delivery system of claim 7, further comprising a
first valve operatively coupled to said feed line and a second
valve operatively coupled to said delivery line, said first valve
configured to prevent flow of LNG to said first storage tank when
compressed natural gas in said first storage tank reaches a
predetermined pressure, and said second valve configured to enable
flow of the compressed natural gas to said delivery line when the
compressed natural gas in said first storage tank reaches the
predetermined pressure.
9. The fuel gas delivery system of claim 6, further comprising a
second storage tank fluidly coupled to said cryocooler and
configured to store LNG from said cryocooler.
10. The fuel gas delivery system of claim 9, further comprising a
second heat exchanger thermally coupled to said second storage tank
and configured to vaporize LNG within said second storage tank,
wherein said first heat exchanger is thermally coupled to said
first storage tank and configured to vaporize LNG within said first
storage tank.
11. The fuel gas delivery system of claim 10, wherein said first
and second heat exchangers are fluidly coupled to said feed line,
each of said first and second heat exchangers configured to receive
and precool the natural gas stream by vaporizing the LNG stored in
one of said first and second storage tanks.
12. The fuel gas delivery system of claim 10, further comprising a
switching valve operatively coupled downstream of said cryocooler,
said switching valve configured to selectively direct the LNG
stream to one of said first and second storage tanks.
13. The fuel gas delivery system of claim 11, further comprising a
switching valve operatively coupled to said feed line, said
switching valve configured to selectively direct the natural gas
stream to one of said first and second heat exchangers.
14. The fuel gas delivery system of claim 10, further comprising
first and second valves operatively coupled to said delivery line,
wherein said first and second valves are configured to enable flow
of the compressed natural gas to said delivery line, respectively,
when the compressed natural gas in said first and second storage
tanks reaches a predetermined pressure.
15. The fuel gas delivery system of claim 1, wherein the impurities
comprises water.
16. A fuel gas delivery system comprising: a feed line configured
to provide a natural gas stream; a cryocooler fluidly coupled to
said feed line, said cryocooler configured to cool said natural gas
below the freezing point of impurities contained in said natural
gas stream to separate the frozen impurities from a cooled and
densified natural gas stream; a first heat exchanger fluidly
coupled to said cryocooler, said first heat exchanger configured to
heat and pressurize at least a portion of the cooled and densified
stream to provide compressed natural gas; a delivery line
configured to supply the compressed natural gas to an end user; and
a removal line configured to remove the frozen impurities from said
fuel delivery system.
17. The fuel gas delivery system of claim 16, further comprising a
storage tank fluidly coupled to said cryocooler and configured to
store the cooled and densified natural gas stream from said
cryocooler, said storage tank including an adsorbent material
configured to adsorb the cooled and densified natural gas stream
removed of said impurities, wherein said first heat exchanger is
thermally coupled to said storage tank.
18. The fuel gas delivery system of claim 17, wherein said
adsorbent material is a carbon adsorbent material.
19. The fuel gas delivery system of claim 17, further comprising a
first valve operatively coupled to said feed line and a second
valve operatively coupled to said delivery line, said first valve
configured to prevent flow of the cooled and condensed natural gas
stream to said storage tank when compressed natural gas in said
first storage tank reaches a predetermined pressure, and said
second valve configured to enable flow of the compressed natural
gas to said delivery line when said compressed natural gas in said
first storage tank reaches the predetermined pressure.
20. A method of supplying purified compressed fuel gas, the method
comprising: supplying a natural gas stream to a cryocooler of a
compressed natural gas delivery system; freezing impurities
contained in the natural gas stream; condensing the natural gas to
provide a liquefied natural gas (LNG) stream; separating the frozen
impurities from the LNG stream; vaporizing the LNG stream to
provide a compressed natural gas stream at a predetermined
pressure; and supplying the compressed natural gas to a delivery
line.
21. The method of claim 20, further comprising depressurizing and
warming at least a portion of the gas delivery system to warm the
separated impurities, and extracting the warmed impurities from the
fuel delivery system.
22. The method of claim 21, further comprising precooling the
natural gas stream against the LNG stream prior to condensing in
the cryocooler, wherein the LNG stream is vaporized.
23. The method of claim 21, further comprising delivering the LNG
stream to a first storage tank, wherein the LNG is vaporized in the
first storage tank.
24. The method of claim 23, further comprising opening a first
valve when the compressed natural gas in the first storage tank
reaches a predetermined pressure to supply the compressed natural
gas to the delivery line, and closing a second valve when the
compressed natural gas reaches the predetermined pressure to
prevent flow of the LNG stream to the first storage tank.
25. The method of clam 23, further comprising delivering the LNG to
a second storage tank, and precooling the natural gas stream
against LNG in one of the first and second storage tanks by
selectively supplying the natural gas stream to one of the first
and second storage tanks, wherein the LNG is vaporized in one of
the first and second storage tanks.
26. The method of claim 24, further comprising precooling the
natural gas stream against the first storage tank filled with LNG
while LNG is supplied to the second storage tank to fill the second
storage tank with LNG.
27. A method of delivering a high purity compressed fuel gas, the
method comprising: supplying a natural gas stream to a cryocooler
of a compressed fuel gas delivery system; cooling the natural gas
in the cryocooler to a temperature below the freezing point of
impurities contained in the natural gas stream; separating the
frozen impurities from the condensed natural gas to provide a
cooled and densified natural gas stream; pressurizing the cooled
and densified stream to provide a compressed natural gas stream at
a predetermined pressure; and delivering the compressed natural gas
to a delivery line.
28. The method of claim 27, further comprising depressurizing and
warming at least a portion of the fuel gas delivery system to warm
the frozen impurities to a liquid or gas, and extracting the warmed
impurities from the fuel delivery system.
29. The method of claim 27, further comprising supplying the cooled
and densified natural gas stream to a storage tank and adsorbing
the cooled and densified natural gas stream in an adsorbent
material contained in the storage tank.
30. The method of claim 29, wherein the adsorbent material is at
least one of a carbon adsorbent material and metal organic
frameworks.
31. The method of claim 29, further comprising opening a first
valve when the compressed natural gas in the first storage tank
reaches a predetermined pressure to supply the compressed natural
gas to the delivery line, and closing a second valve when the
compressed natural gas reaches the predetermined pressure to
prevent flow of the cooled and densified stream to the storage
tank.
32. A method of removing impurities from a fuel gas stream in a
fuel gas delivery system, the method comprising: supplying a
natural gas stream to a cryocooler of the fuel delivery system, the
cryocooler configured to condense the natural gas to a liquefied
natural gas (LNG) stream and freeze impurities contained in the
natural gas; separating the impurities from the LNG stream;
selectively supplying the LNG stream to one of a first storage tank
and a second storage tank; selectively precooling the natural gas
stream against LNG in the first storage tank when the first storage
tank is filled with a predetermined amount of LNG, wherein the LNG
is vaporized into compressed natural gas; selectively precooling
the natural gas stream against the LNG in the second storage tank
when the second storage tank is filled with a predetermined amount
of LNG, wherein the LNG is vaporized into compressed natural gas;
opening a first valve when the compressed natural gas in the first
tank is at a predetermined pressure to supply the compressed
natural gas to a delivery line, and opening a second valve when the
compressed natural gas in the second tank is at the predetermined
pressure to supply the compressed natural gas to the delivery line;
and wherein LNG is vaporized in the first tank while the second
tank is being filled with LNG from the cryocooler and LNG is
vaporized in the second tank while the first tank is being filled
with LNG from the cryocooler to provide a steady supply of
compressed natural gas to the delivery line.
Description
BACKGROUND OF THE INVENTION
[0001] The field of the invention relates generally to natural gas
distribution, and specifically to a natural gas dispensing system
for a vehicle.
[0002] Motor vehicles that operate on gaseous fuels such as natural
gas and hydrogen are refueled at stations that dispense gas at high
pressure. While commercial refueling stations are capable of
refueling a motor vehicle in minutes, residential refueling
stations typically refuel motor vehicles over a period of several
hours. Typical residential refueling stations use compressors to
pressurize the gas to the required delivery pressure. These known
compression systems are typically slow, generate vibrations and
noise pollution, and may be expensive to operate due to high power
consumption. Known residential refueling stations also typically
include adsorption-based moisture removal systems. Such known
adsorption-based removal systems can be inefficient, costly and
present additional components that require maintenance and further
complicate the system.
BRIEF DESCRIPTION OF THE INVENTION
[0003] In one embodiment, a fuel gas delivery system is provided.
The fuel gas delivery system includes a feed line configured to
provide a natural gas stream and a cryocooler fluidly coupled to
the feed line. The cryocooler is configured to condense the natural
gas to provide a liquefied natural gas (LNG) stream and to freeze
impurities contained in the natural gas stream. The frozen
impurities are separated from said LNG stream. A first heat
exchanger is fluidly coupled to the cryocooler and the first heat
exchanger is configured to vaporize at least a portion of the LNG
stream to provide compressed natural gas. A delivery line is
configured to supply the compressed natural gas to an end user and
a removal line is configured to remove the impurities from the fuel
gas delivery system.
[0004] In another embodiment, a fuel gas delivery system is
provided. The fuel gas delivery system includes a feed line
configured to provide a natural gas stream and a cryocooler fluidly
coupled to the feed line. The cryocooler is configured to cool the
natural gas below the freezing point of impurities contained in the
natural gas stream to separate the frozen impurities from a cooled
and densified natural gas stream. A first heat exchanger is fluidly
coupled to the cryocooler and the first heat exchanger is
configured to vaporize at least a portion of the cooled and
densified stream to provide compressed natural gas. A delivery line
is configured to supply the compressed natural gas to an end user
and a removal line is configured to remove the impurities from the
fuel delivery system.
[0005] In yet another embodiment, a method of supplying purified
compressed fuel gas is provided. The method includes supplying a
natural gas stream to a cryocooler of a compressed natural gas
delivery system, freezing impurities contained in the natural gas
stream and condensing the natural gas to provide an LNG stream. The
method further includes separating the frozen impurities from the
LNG stream, vaporizing the LNG stream to provide a compressed
natural gas stream at a predetermined pressure, and supplying the
compressed natural gas to a delivery line.
[0006] In yet another embodiment, a method of delivering a high
purity compressed fuel gas is provided. The method includes
supplying a natural gas stream to a cryocooler of a compressed fuel
gas delivery system, cooling the natural gas in the cryocooler to a
temperature below the freezing point of impurities contained in the
natural gas stream, and separating the frozen impurities from the
condensed natural gas to provide a cooled and densified natural gas
stream. The method further includes vaporizing the cooled and
densified stream to provide a compressed natural gas stream at a
predetermined pressure, and delivering the compressed natural gas
to a delivery line.
[0007] In yet another embodiment, a method of removing impurities
from a fuel gas stream in a fuel gas delivery system is provided.
The method includes supplying a natural gas stream to a cryocooler
of the fuel delivery system. The cryocooler is configured to
condense the natural gas to an LNG stream, freeze impurities
contained in the natural gas, and separate the impurities from the
LNG stream. The method further includes selectively supplying the
LNG stream to one of a first storage tank and a second storage
tank, and selectively precooling the natural gas stream against LNG
in the first storage tank when the first storage tank is filled
with a predetermined amount of LNG. The LNG is vaporized into
compressed natural gas. The method further includes selectively
precooling the natural gas stream against the LNG in the second
storage tank when the second storage tank is filled with a
predetermined amount of LNG. The LNG is vaporized into compressed
natural gas. The method further includes opening a first valve when
the compressed natural gas in the first tank is at a predetermined
pressure to supply the compressed natural gas to a delivery line,
and opening a second valve when the compressed natural gas in the
second tank is at the predetermined pressure to supply the
compressed natural gas to the delivery line. The LNG is vaporized
in the first tank while the second tank is being filled with LNG
from the cryocooler and LNG is vaporized in the second tank while
the first tank is being filled with LNG from the cryocooler to
provide a steady supply of compressed natural gas to the delivery
line.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic view of an exemplary gaseous fuel
delivery system according to the present disclosure;
[0009] FIG. 2 is a schematic view of another exemplary gaseous fuel
delivery system according to the present disclosure;
[0010] FIG. 3 is a schematic view of an even further exemplary
gaseous fuel delivery system according to the present disclosure;
and
[0011] FIG. 4 is a schematic view of an even further exemplary
gaseous fuel delivery system according to the present
disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[0012] Known gaseous fuel delivery systems utilize adsorption-based
removal systems to remove impurities from gaseous fuel and
compressors to provide fuel at high pressure. In contrast, the
present system utilizes a cryocooler based system to remove
impurities and provide fuel at high pressure, without the need for
a compressor or an adsorption-based removal system.
[0013] FIG. 1 illustrates an exemplary embodiment of a fuel gas
delivery system 10 that generally includes a feed line 12, a
regenerator 14, a cryocooler 16 and a delivery line 18. Delivery
system 10 is configured to purify and increase the pressure of a
fuel gas such as, for example, natural gas, hydrogen, hydrocarbon,
or similar gaseous fuel. The high pressure compressed fuel gas may
be used to power machinery such as, for example, a vehicle. For
exemplary purposes, natural gas will be described herein as the
gaseous fuel.
[0014] In the exemplary embodiment, feed line 12 is fluidly coupled
to cryocooler 16 and is configured to supply natural gas thereto.
Feed line 12 is fluidly connected to a source (not shown) of
natural gas such as, for example, a residential natural gas line.
Cryocooler 16 includes a cold head 20 that is capable of producing
extremely low temperatures at cold head 20, for example below 2 K.
Cryocooler 16 may be any type of known cryocooler that enables
delivery system 10 to function as described herein such as, for
example, a GM, Stirling, or pulse tube cryocooler.
[0015] In the exemplary embodiment, cryocooler 16 cools and
condenses natural gas from feed line 12 to provide a liquefied
natural gas (LNG) stream to delivery line 18. Because of the
extremely low temperatures required to liquefy the natural gas,
impurities having a higher freezing point than natural gas are
frozen and thus separated from the LNG stream. The frozen
impurities, for example water, hydrocarbons, and hydrogen sulfide,
adhere to cold head 20 and/or surrounding structure of feed line
12, cryocooler 16, and delivery line 18. The frozen impurities are
later removed from the system via removal line 28, as will be
described below.
[0016] In the exemplary embodiment, the LNG stream passes from
cryocooler 16 to pump 22 where it is raised in pressure to a
suitable delivery pressure. The high-pressure LNG stream then
passes to regenerator 14 where it is warmed in indirect heat
exchange with natural gas in feed line 12 to precool the natural
gas. Precooling the natural gas stream in feed line 12 against the
LNG stream in delivery line 18 increases system efficiency by
reducing the cooling and power consumption required of cryocooler
16 to condense the natural gas stream. The high-pressure LNG stream
may be at least partially vaporized and pressurized in regenerator
14 to produce a high-pressure compressed natural gas (CNG) stream
that is supplied through delivery line 18 to storage and/or a
vehicle (not shown). A heat exchanger 24 may be thermally coupled
to delivery line 18 to provide additional heating to completely
vaporize the high-pressure LNG stream. Heat exchanger 24 may be,
for example, an electrical heater or an ambient air heat exchanger.
A cooler 26 may also be provided in delivery line 18 to remove
excess heat before the CNG stream is dispensed to an end user.
[0017] In the exemplary embodiment, fuel gas delivery system 10 may
optionally include an intermediate buffer tank 30 coupled to
delivery line 18. Buffer tank 30 is filled with CNG and is
configured to store CNG at a pressure higher than a vehicle fuel
tank dispensing pressure. Fuel gas delivery system 10 is configured
to fill buffer tank 30 over the course of several hours to a whole
day, resulting in a considerably reduced size requirement and
operational cost for fuel delivery system 10. When required, buffer
tank 30 dispenses the stored CNG at the dispensing pressure to an
end user, for example a vehicle fuel tank (not shown). Thus, buffer
tank 30 is configured to provide a relatively large supply of CNG
for quickly refueling a vehicle.
[0018] In operation, natural gas is supplied through feed line 12
and is precooled in regenerator 14. The precooled natural gas
stream is further cooled and at least partially condensed by
cryocooler cold head 20 and/or surrounding cooled components.
During cooling in regenerator 14 and/or against cold head 20 and
surrounding components, impurities contained within the natural gas
stream are frozen and separated from the condensed LNG stream. The
frozen impurities adhere to surfaces within delivery system 10
and/or are captured by a separate capturing device (not shown). The
LNG stream is supplied through the delivery line 18, pumped to a
delivery pressure in pump 22, and warmed and/or vaporized in
regenerator 14 and heat exchanger 24. The resulting CNG stream is
cooled in cooler 26 and is dispensed to an end user or stored for
later use, such as in intermediate buffer tank 30.
[0019] In the exemplary embodiment, once CNG delivery through
delivery line 18 is complete, fuel delivery system 10 may be
operated in a regeneration mode. During regeneration mode, fuel
delivery system 10 is disconnected from the natural gas supply and
is depressurized and warmed to near ambient temperature. As a
result, the frozen impurities separated and captured in the
dispensing mode are warmed and become gas and/or liquid. A valve 29
in removal line 28 is opened and the captured impurities are
removed from system 10. Fuel gas delivery system 10 may then return
to a dispensing mode and repeat the above process.
[0020] FIG. 2 illustrates an exemplary embodiment of a further
gaseous fuel delivery system 100 that is similar to fuel delivery
system 10, and like reference numerals refer to like parts. Fuel
delivery system 100 is similar to fuel delivery system 10 except it
includes a storage tank 42 instead of regenerator 14. Fuel delivery
system 100 generally includes a feed line 12, a cryocooler 16, an
LNG line 40, storage tank 42 and a delivery line 18.
[0021] In the exemplary embodiment, feed line 12 is fluidly coupled
to cryocooler 16 and is configured to supply natural gas thereto.
Natural gas condensed by cryocooler 16 and/or surrounding
components is supplied as an LNG stream to LNG line 40. Frozen
impurities are separated and removed from the natural gas stream,
as described above. Storage tank 42 is fluidly coupled to LNG line
40 and receives the LNG stream from cryocooler 16. In the exemplary
embodiment, a heater 44 is thermally coupled to storage tank 42 to
vaporize LNG stored therein to provide CNG. Alternatively, feed
line 12 may be thermally coupled to storage tank 42 to provide
indirect heat exchange between the natural gas stream and LNG
stored in storage tank 42 to vaporize the stored LNG. Delivery line
18 is fluidly coupled to storage tank 42 to receive the CNG and
deliver a CNG stream to a buffer tank 30 and/or an end user. Fuel
delivery system 100 also includes a valve 46 operatively associated
with feed line 12 to control flow of the natural gas stream to
cryocooler 16, and a valve 48 operatively associated with delivery
line 18 to control flow of CNG from storage tank 42.
[0022] In operation, valve 46 is in an open state and natural gas
in feed line 12 is supplied to cryocooler 16 for condensing and
separation of impurities, as described above. Valve 48 is in a
closed state and prevents fluid from entering delivery line 18 from
storage tank 42. LNG is supplied from cryocooler 16 to storage tank
42 via LNG line 40 until storage tank 42 reaches a predetermined
level of LNG. Upon reaching the predetermined level of LNG, valve
46 is closed to prevent further filling of storage tank 42. Heater
44 then begins to vaporize and pressurize the stored LNG until the
resulting CNG reaches a predetermined pressure at which point valve
48 is opened to supply CNG through delivery line 18 to buffer tank
30 and/or an end user. Additionally, a pump (not shown) may be
provided in delivery line 18 to pump the CNG to a desired
pressure.
[0023] Once the CNG stream is delivered, fuel delivery system 100
may enter a regeneration mode. Valve 46 is opened and fuel delivery
system 100 is disconnected from the natural gas supply and is
depressurized and warmed to near ambient temperature. As a result,
the frozen impurities separated and captured in the dispensing mode
are warmed and extracted via removal line 28, as described above.
Fuel delivery system 100 may then return to a dispensing mode and
repeat the above operations.
[0024] FIG. 3 illustrates an exemplary embodiment of a further
gaseous fuel delivery system 200 that is similar to fuel delivery
system 100 and like reference numerals refer to like parts. Fuel
delivery system 200 is similar to fuel delivery system 100 except
it includes an adsorbent material 32 in a storage tank 42 and a
natural gas feed stream is chilled, but not condensed. Fuel
delivery system 200 generally includes a feed line 12, a cryocooler
16, a chilled natural gas line 41, storage tank 42 and a delivery
line 18.
[0025] In the exemplary embodiment, feed line 12 is fluidly coupled
to cryocooler 16 and is configured to supply natural gas thereto.
Natural gas is chilled and densified by cryocooler 16 and/or
surrounding components and is supplied as a cooled and densified
natural gas stream to chilled natural gas line 41. Alternatively,
cryocooler 16 may simply be any cooler or chiller capable of
lowering the temperature of the natural gas stream below the
freezing point of the impurities desired to be separated. Frozen
impurities are separated and removed from the natural gas stream,
as described above. In addition, some impurities may only be
condensed and are removed by, for example, a trap, a knockout
device, or the like. Storage tank 42 is fluidly coupled to chilled
natural gas line 41 and receives the chilled stream from cryocooler
16.
[0026] In the exemplary embodiment, storage tank 42 includes
adsorbent material 32 to adsorb the chilled and densified natural
gas. Adsorbent material 32 may be any material enabling fuel gas to
be adsorbed as described herein such as, for example, a carbon
adsorbent and/or metal organic frameworks. Typically, impurities
impede gas adsorption; however the removal of impurities upstream
of storage tank 42 improves adsorption of the densified gas and
thereby reduces the volumetric requirement of storage tank 42.
Thus, storage tank 42 may be smaller, resulting in reduced space
requirements for fuel delivery system 200.
[0027] In the exemplary embodiment, a heater 44 is thermally
coupled to storage tank 42 to desorb and pressurize the densified
natural gas stored in adsorbent material 32 to provide CNG.
Alternatively, feed line 12 may be thermally coupled to storage
tank 42 to provide indirect heat exchange between the natural gas
stream and gas adsorbed in storage tank 42 to desorb the stored
natural gas. Delivery line 18 is fluidly coupled to storage tank 42
to receive the CNG and supply a CNG stream to a buffer tank 30
and/or an end user. Fuel delivery system 200 also includes a valve
46 operatively associated with chilled natural gas line 41 to
control flow of the natural gas stream to storage tank 42, and a
valve 48 operatively associated with delivery line 18 to control
flow of CNG from storage tank 42. Alternatively, valve 46 may be
upstream of cryocooler 16.
[0028] In operation, valve 46 is in an open state and natural gas
in feed line 12 is supplied to cryocooler 16 for chilling and
separation of impurities, as described above. Valve 48 is in a
closed state and prevents fluid from entering delivery line 18 from
storage tank 42. Chilled and densified natural gas is supplied from
cryocooler 16 to storage tank 42 via chilled natural gas line 41
until adsorbent material 32 adsorbs a predetermined level or volume
of densified natural gas. Upon reaching the predetermined level of
adsorption, valve 46 is closed to prevent further filling of
storage tank 42. Heater 44 then begins to desorb and pressurize the
stored natural gas until the resulting CNG reaches a predetermined
pressure at which point valve 48 is opened to deliver CNG through
delivery line 18 to buffer tank 30 and/or an end user.
Additionally, a pump (not shown) may be provided in delivery line
18 to pump the CNG to a desired pressure.
[0029] Once the CNG stream is delivered, fuel delivery system 200
may enter a regeneration mode. Valve 46 is opened and fuel delivery
system 100 is disconnected from the natural gas supply and is
depressurized and warmed to near ambient temperature. As a result,
the frozen and/or condensed impurities separated and captured in
the dispensing mode are warmed and extracted via removal line 28,
as described above. Fuel delivery system 200 may then return to a
dispensing mode and repeat the above operations.
[0030] FIG. 4 illustrates an exemplary embodiment of a further
gaseous fuel delivery system 300 that is similar to fuel delivery
systems 10 and 100, and like reference numerals refer to like
parts. Fuel delivery system 300 is similar to fuel delivery system
100 except it includes a second storage tank 50. Fuel delivery
system 300 generally includes a feed line 12, a cryocooler 16, an
LNG line 40, a first storage tank 42, second storage tank 50, and a
delivery line 18.
[0031] In the exemplary embodiment, feed line 12 is split at a
switching valve 52 into split feed lines 54 and 56. Split feed
lines 54 and 56 are fluidly coupled to cryocooler 16 and are
configured to supply natural gas thereto. Switching valve 52
selectively supplies natural gas to either of split feed lines 54
and 56. Natural gas condensed by cryocooler 16 and/or surrounding
components is supplied as an LNG stream to LNG line 40. Frozen
impurities separated and removed from the natural gas stream, as
described above. LNG line 40 is split at a switching valve 58 into
split LNG lines 60 and 62. Switching valve 58 selectively supplies
LNG to either of split LNG lines 60 and 62.
[0032] In the exemplary embodiment, storage tank 42 is fluidly
coupled to split LNG line 60 and storage tank 50 is fluidly coupled
to split LNG line 62 to receive LNG from cryocooler 16. In the
exemplary embodiment, split feed line 54 is thermally coupled to
storage tank 42 to provide indirect heat exchange between natural
gas in line 54 and LNG stored in storage tank 42. Similarly, split
feed line 56 is thermally coupled to storage tank 50 to provide
indirect heat exchange between natural gas in line 56 and LNG
stored in storage tank. In this arrangement, natural gas in split
lines 54 and 56 is precooled against vaporizing LNG stored in
respective storage tanks 42 and 50. Alternatively, or in addition,
a heater (not shown) may be thermally coupled to storage tank 42
and/or 50 to vaporize LNG stored therein to provide CNG.
[0033] In the exemplary embodiment, delivery line 18 is fluidly
coupled to storage tanks 42 and 50 to receive CNG therefrom and
supply a CNG stream to a buffer tank 30 and/or an end user. A valve
48 is operatively associated with delivery line 18 to control flow
of CNG from storage tank 42 and a valve 64 is operatively
associated with delivery line 18 to control flow of CNG from
storage tank 50.
[0034] In general, during operation, fuel delivery system 300 fills
one of storage tanks 42 and 50 while the other already filled tank
undergoes vaporization and pressurization of LNG stored therein.
Once the CNG in the filled tank reaches a predetermined pressure,
the CNG is supplied to delivery line 18 and vaporization and
pressurization of the other now filled tank begins while filling of
the now evacuated tank begins. The process is repeated and thus,
fuel delivery system 300 is configured to provide a steady flow of
CNG.
[0035] In more detail, during operation, switching valve 52
supplies gas from feed line 12 through split feed line 54 where it
is precooled against LNG stored in storage tank 42. The precooled
natural gas is then supplied to cryocooler 16 for condensing and
separation of impurities, as described above. Valve 48 is in a
closed state and prevents fluid from entering delivery line 18
while LNG is vaporized and pressurized in storage tank 42 until the
CNG reaches a predetermined pressure. Switching valve 58 supplies
LNG from cryocooler 16 to evacuated storage tank 50 via split LNG
line 62 until storage tank 50 reaches a predetermined level of LNG.
Once the CNG in storage tank 42 reaches the predetermined pressure,
valve 48 is opened and CNG is supplied to delivery line 18 to
buffer tank 30 and/or an end user.
[0036] Once storage tank 42 is evacuated, switching valve 52
directs the supply of natural gas into split feed line 56 to
precool the natural gas and commence vaporization and
pressurization of LNG in filled storage tank 50. Alternatively,
vaporization and pressurization of storage tank 50 may occur during
evacuation of storage tank 42. Valve 64 is in a closed state and
prevents fluid from entering delivery line 18 while LNG is
vaporized and pressurized in storage tank 50 until the resulting
CNG reaches the predetermined pressure. The natural gas precooled
in line 56 is then supplied to cryocooler 16 for condensing and
separation of impurities. Switching valve 58 supplies LNG from
cryocooler 16 to now evacuated storage tank 42 until storage tank
42 reaches the predetermined level of LNG. Once the CNG in storage
tank 50 reaches the predetermined pressure, valve 64 is opened and
CNG is supplied to delivery line 18 to buffer tank 30 and/or an end
user. Additionally, a pump (not shown) may be provided in delivery
line 18 to pump the CNG to a desired pressure. The operation may be
repeated to alternate storage tanks 42 and 50 between a filling
mode and a vaporization, pressurization and evacuation mode.
[0037] At a predetermined time, fuel delivery system 300 may enter
a regeneration mode. Valves 48 and 64 may be closed and fuel
delivery system 300 is disconnected from the natural gas supply and
is depressurized and warmed to near ambient temperature. As a
result, the frozen impurities separated and captured in the
dispensing mode are warmed and extracted via removal line 28, as
described above. Fuel delivery system 300 may then return to a
dispensing mode and repeat the above operations.
[0038] As described above, the gaseous fuel systems of the present
invention provide removal of impurities from a gaseous fuel by
lowering the temperature of the gaseous fuel below the freezing
point of the impurities desired to be removed, thus not requiring
an adsorption based removal system. Further, the gaseous fuel
systems of the present invention vaporize and pressurize gas to
provide a compressed gas without requiring a compressor, thereby
reducing vibrations and power consumption. The gaseous fuel systems
of the present invention also provide quick refueling of vehicles.
For example, 5 kg of CNG can be dispensed in less than an hour.
Moreover, the systems may utilize heat exchange between various
fuel streams in the system to improve thermal efficiency and energy
usage. Thus, the gaseous fuel systems described above provide
quiet, compact and efficient systems to remove impurities and
provide compressed fuel to storage, a vehicle, or the like.
[0039] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they have structural elements that do not differ
from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the claims.
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