U.S. patent application number 11/233378 was filed with the patent office on 2007-10-04 for systems and methods for low-temperature gas separation.
Invention is credited to Vadim Ivanovich Alferov, Lev Arkad'evich Bagirov, Leonard Makarovich Dmitriev, Vladimir Isaakovich Feygin, Salavat Zainetdinovich Imaev.
Application Number | 20070227186 11/233378 |
Document ID | / |
Family ID | 36089810 |
Filed Date | 2007-10-04 |
United States Patent
Application |
20070227186 |
Kind Code |
A1 |
Alferov; Vadim Ivanovich ;
et al. |
October 4, 2007 |
Systems and methods for low-temperature gas separation
Abstract
One of the drawbacks common to many currently available
low-temperature gas mixture separation techniques is that known
systems and methods that embody the techniques are inefficient. In
contrast to known systems and methods for low-temperature gas
mixture separation, some embodiments of the present invention
provide a system for low-temperature gas mixture separation that
recycles energy and reduces power consumption by re-circulating
heated and/or cooled flows (e.g. gas, liquid and mixed-phase flows)
within the system. Accordingly, in some embodiments efficiency is
somewhat improved, as compared to comparable systems that do not
include the re-circulation of heat energy. In some embodiments the
heat energy that is re-circulated is a combination of heat added to
the system (i.e. inputs to the system) and heat released within the
system (i.e. byproducts from within the system) that are
subsequently recovered. In particular, some systems and methods
provided in accordance with embodiments of the invention are suited
for separating the constituent components of natural gas and other
hydrocarbon gas mixtures.
Inventors: |
Alferov; Vadim Ivanovich;
(Moscow, RU) ; Bagirov; Lev Arkad'evich; (Moscow,
RU) ; Feygin; Vladimir Isaakovich; (Moscow, RU)
; Imaev; Salavat Zainetdinovich; (Ramenskoe, RU) ;
Dmitriev; Leonard Makarovich; (Zukovskiy, RU) |
Correspondence
Address: |
NIXON & VANDERHYE, PC
901 NORTH GLEBE ROAD, 11TH FLOOR
ARLINGTON
VA
22203
US
|
Family ID: |
36089810 |
Appl. No.: |
11/233378 |
Filed: |
September 23, 2005 |
Current U.S.
Class: |
62/620 |
Current CPC
Class: |
F25J 2200/76 20130101;
F25J 2230/08 20130101; F25J 2270/04 20130101; B01D 5/0033 20130101;
F25J 2200/02 20130101; F25J 2200/70 20130101; F25J 2240/60
20130101; B01D 5/0045 20130101; F25J 3/0233 20130101; F25J 2210/04
20130101; F25J 2230/60 20130101; F25J 2205/04 20130101; F25J 3/0209
20130101; F25J 2270/02 20130101; F25J 2240/02 20130101; F25J 3/0238
20130101; F25J 2270/90 20130101; F25J 2245/02 20130101; F25J
2205/10 20130101; F25J 2270/88 20130101 |
Class at
Publication: |
062/620 |
International
Class: |
F25J 3/00 20060101
F25J003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 24, 2004 |
RU |
2004128348 |
Claims
1. A method of low-temperature gas mixture separation, suitable for
separating components of a hydrocarbon gas mixture, comprising:
cooling a gas mixture; condensing a gas mixture to produce a liquid
stream and a gas/vapor; rectifying at least a portion of the liquid
stream thereby producing respective gas-phase products;
transferring heat energy to or from at least one of the liquid
stream, the gas/vapor stream and gas-phase products from or to at
least another one of the gas mixture, the liquid stream, the
gas/vapor stream, gas-phase products and another flow in order to
recycle energy.
2. A method according to claim 1, further comprising: expanding and
swirling the gas/vapor stream to produce first and second flows,
wherein the first flow primarily includes heavy components of the
gas/vapor stream and the second flow primarily includes lighter
components of the gas/vapor stream; and transferring heat energy to
or from at least one of the liquid stream, the gas/vapor stream,
gas-phase products and the first and second flows from or to at
least another one of the gas mixture, the liquid stream, the
gas/vapor stream, gas-phase products, the another flow and the
first and second flows in order to recycle energy.
3. A method according to 2 further comprising rectifying at least a
portion of the first flow in conjunction with the liquid
stream.
4. A method according to claim 2 wherein cooling the gas mixture
includes at least partially mixing the gas mixture with at least a
portion of at least one of the liquid stream, the gas/vapor stream,
gas-phase products, the another flow and the first and second
flows.
5. A method according to claim 2, wherein cooling the gas mixture
includes at least partially transferring heat from the gas mixture
to at least a portion of at least one of the liquid stream, the
gas/vapor stream, gas-phase products, the another flow and the
first and second flows.
6. A method according to claim 2, further comprising compressing at
least a portion of the gas-phase products.
7. A method according to claim 2 further comprising cooling at
least a portion the gas/vapor stream.
8. A method according to claim 2, further comprising compressing at
least a portion of the first flow.
9. A method according to claim 2, further comprising compressing at
least a portion of the second flow.
10. A method according to claim 2, further comprising cooling at
least a portion of the first flow.
11. A method according to claim 10, further comprising cooling at
least a portion of the second flow.
12. A method according to claim 1, wherein the transfer of heat
energy includes mixing at least a portion of the at least two
streams or flows between which the heat is transferred.
13. A method according to claim 1, wherein the transfer of heat
energy includes exchanging heat energy without mixing the at least
two streams or flows between which the heat is transferred.
14. A method according to claim 1, further comprising passing at
least a portion of the gas/vapor stream through a turbine.
15. A method according to claim 1, further comprising passing at
least a portion of the second flow through a turbine.
16. A method according to claim 1, further comprising condensing at
least a portion of the gas-phase products.
17. A method according to claim 1, further comprising further
condensing at least a portion of the liquid stream.
18. A method according to claim 1, further comprising condensing at
least a portion of the gas/vapor stream.
19. A method according to claim 1, further comprising expanding and
swirling at least a portion of the gas-phase products.
20. A system for low-temperature gas mixture separation, suitable
for separating components of a hydrocarbon gas mixture, comprising:
a first gas/liquid separator for separating an incoming gas mixture
into a liquid stream and a gas/vapor stream; a first expander, for
producing first and second flows, coupled the first gas/liquid
separator to receive the gas/vapor stream, the first expander also
including a swirling means for swirling the gas/vapor stream to
thereby separate heavy components of the gas/vapor stream from the
light components of the gas/vapor stream, wherein the heavy
components primarily comprise the first flow and the lighter
components primarily comprise the second flow; a rectifying tower,
for producing at least gas-phase products, coupled to the first
gas/liquid separator to receive the liquid stream; and at least one
heat exchanger for transferring heat energy to or from at least one
of the liquid stream, the gas/vapor stream, gas-phase products and
the first and second flows from or to at least another one of the
gas mixture, the liquid stream, the gas/vapor stream, gas-phase
products, the another flow and the first and second flows in order
to recycle energy within the system.
21. A system according to claim 20 wherein the first expander is
coupled to the rectifying tower to provide at least a portion of
the first flow to the rectifying tower.
22. A system according to claim 21, further comprising a first
mixer for mixing the incoming gas mixture with a feedback flow, the
feedback flow comprising at least a portion of at least one the
liquid stream, the gas/vapor stream, gas-phase products, the first
and second flows and another flow.
23. A system according to claim 22, further comprising a first
compressor for compressing at least a portion of the gas-phase
products.
24. A system according to claim 22, further comprising a first
compressor for compressing at least a portion of the gas/vapor
stream.
25. A system according to claim 22, further comprising a first
compressor for compressing at least a portion of the first
flow.
26. A system according to claim 22, further comprising a first
compressor for compressing at least a portion of the second
flow.
27. A system according to claim 20, further comprising a first
chiller for cooling at least a portion of the first flow.
28. A system according to claim 20, further comprising a first
chiller for cooling at least a portion of the second flow.
29. A system according to claim 20, wherein the transfer of heat
energy includes mixing at least a portion of the at least two
streams or flows between which the heat is transferred.
30. A system according to claim 20, wherein the transfer of heat
energy includes exchanging heat energy without mixing the at least
two streams or flows between which the heat is transferred.
31. A system according to claim 20, further comprising a turbine,
for expanding at least a portion of the gas/vapor stream, coupled
to the first gas/liquid separator to receive at least a portion of
the gas/vapor stream.
32. A system according to claim 20, further comprising a turbine
through which at least a portion of the second flow passes, the
turbine coupled to receive at least a portion of the second
flow.
33. A system according to claim 20, further comprising at least one
other gas/liquid separator for separating at least one of a liquid
or a gas/vapor stream within the system.
34. A system according to claim 20, further comprising another
condenser for further condensing at least a portion of the liquid
stream.
35. A system according to claim 20, further comprising another
condenser for condensing at least a portion of the gas/vapor
stream.
36. A system according to claim 20, further comprising another
expander for expanding and swirling at least a portion of the
gas-phase products.
Description
PRIORITY CLAIM
[0001] This application claims the benefit of Russian Patent
Application No. 2004128348/06 (030834), filed on Sep. 24, 2004, and
the entire content of which is hereby incorporated by
reference.
FIELD OF THE INVENTION
[0002] The invention relates to gas separation techniques, and in
particular to systems and methods for low-temperature gas
separation.
BACKGROUND OF THE INVENTION
[0003] Existing processes of low temperature separation of the
aimed components from the gas mixtures are based on the gas
mixtures chilling, aim components condensation and subsequent
separation of the condensate, containing the aimed components, from
the gas mixture. At this the chilling of a gas mixture is
conventionally performed either at the expense of gas expansion in
the throttles and expanders or the application of chilling devices.
As additional auxiliary equipment recuperative heat exchangers and
rectifying towers are used in the schemes of low temperature gas
separation.
[0004] The typical processes of low temperature separation of the
aimed components from the gas mixtures are described, for example,
in the U.S. Pat. No. 6,182,468B1 and RU2047061C1. The method
disclosed in U.S. Pat. No. 6,182,468B1 is based on the gas chilling
at the expense of gas mixture throttling in Joule-Thompson valve
while in the Patent RU2047061C1 the turbo expander turbine is used
for the gas chilling.
[0005] The method of U.S. Pat. No. 6,182,468B1 consists of cooling
of a mixture, expansion of the mixture without doing mechanical
work, partial condensation of the mixture during its expansion,
separation of the mixture or its part in the rectifying tower to
obtain the products in liquid and gas phase. In this case, cooling
of the mixture is performed using recuperative heat exchangers and
a chiller, while expansion of the mixture is achieved by means of
mixture throttling in the Joule-Thomson valve.
[0006] The method of Patent RU2047061C1 includes cooling of a
mixture and its separation into vapor and liquid phases, expansion
of one part of the vapor phase without doing mechanical work and
that of the other part by doing mechanical work, separation of the
expanded mixture in the rectifying tower to obtain gas and liquid
products.
[0007] The essential drawbacks of these methods of low temperature
gas separation are the significant mixture pressure losses in the
low temperature separation process and high energy consumption.
SUMMARY OF THE INVENTION
[0008] According to an aspect of an embodiment of the invention
there is provided a method of low-temperature gas mixture
separation, suitable for separating components of a hydrocarbon gas
mixture, including: cooling a gas mixture; condensing a gas mixture
to produce a liquid stream and a gas/vapor; rectifying at least a
portion of the liquid stream thereby producing respective gas-phase
products; transferring heat energy to or from at least one of the
liquid stream, the gas/vapor stream and gas-phase products from or
to at least another one of the gas mixture, the liquid stream, the
gas/vapor stream, gas-phase products and another flow in order to
recycle energy.
[0009] In some embodiments the method also includes expanding and
swirling the gas/vapor stream to produce first and second flows,
wherein the first flow primarily includes heavy components of the
gas/vapor stream and the second flow primarily includes lighter
components of the gas/vapor stream; and transferring heat energy to
or from at least one of the liquid stream, the gas/vapor stream,
gas-phase products and the first and second flows from or to at
least another one of the gas mixture, the liquid stream, the
gas/vapor stream, gas-phase products, the another flow and the
first and second flows in order to recycle energy.
[0010] In some more specific embodiments the method also includes
rectifying at least a portion of the first flow in conjunction with
the liquid stream.
[0011] In some more specific embodiments cooling the gas mixture
includes at least partially mixing the gas mixture with at least a
portion of at least one of the liquid stream, the gas/vapor stream,
gas-phase products, the another flow and the first and second
flows.
[0012] In some more specific embodiments cooling the gas mixture
includes at least partially transferring heat from the gas mixture
to at least a portion of at least one of the liquid stream, the
gas/vapor stream, gas-phase products, the another flow and the
first and second flows.
[0013] In some more specific embodiments the method also includes
compressing at least a portion of the gas-phase products.
[0014] In some more specific embodiments the method also includes
cooling at least a portion the gas/vapor stream.
[0015] In some more specific embodiments the method also includes
compressing at least a portion of the first flow.
[0016] In some more specific embodiments the method also includes
compressing at least a portion of the second flow.
[0017] In some more specific embodiments the method also includes
cooling at least a portion of the first flow.
[0018] In some more specific embodiments cooling at least a portion
of the second flow.
[0019] In some more specific embodiments the transfer of heat
energy includes mixing at least a portion of the at least two
streams or flows between which the heat is transferred.
[0020] In some more specific embodiments the transfer of heat
energy includes exchanging heat energy without mixing the at least
two streams or flows between which the heat is transferred.
[0021] In some more specific embodiments the method also includes
passing at least a portion of the gas/vapor stream through a
turbine.
[0022] In some more specific embodiments the method also includes
passing at least a portion of the second flow through a
turbine.
[0023] In some more specific embodiments the method also includes
condensing at least a portion of the gas-phase products.
[0024] In some more specific embodiments the method also includes
further condensing at least a portion of the liquid stream.
[0025] In some more specific embodiments the method also includes
condensing at least a portion of the gas/vapor stream.
[0026] In some more specific embodiments the method also includes
expanding and swirling at least a portion of the gas-phase
products.
[0027] According to an aspect of an embodiment of the invention
there is provided a system for low-temperature gas mixture
separation, suitable for separating components of a hydrocarbon gas
mixture, including: a first gas/liquid separator for separating an
incoming gas mixture into a liquid stream and a gas/vapor stream; a
first expander, for producing first and second flows, coupled the
first gas/liquid separator to receive the gas/vapor stream, the
first expander also including a swirling means for swirling the
gas/vapor stream to thereby separate heavy components of the
gas/vapor stream from the light components of the gas/vapor stream,
wherein the heavy components primarily comprise the first flow and
the lighter components primarily comprise the second flow; a
rectifying tower, for producing at least gas-phase products,
coupled to the first gas/liquid separator to receive the liquid
stream; and at least one heat exchanger for transferring heat
energy to or from at least one of the liquid stream, the gas/vapor
stream, gas-phase products and the first and second flows from or
to at least another one of the gas mixture, the liquid stream, the
gas/vapor stream, gas-phase products, the another flow and the
first and second flows in order to recycle energy within the
system.
[0028] In some embodiments the first expander is coupled to the
rectifying tower to provide at least a portion of the first flow to
the rectifying tower.
[0029] In some more specific embodiments the system also includes a
first mixer for mixing the incoming gas mixture with a feedback
flow, the feedback flow comprising at least a portion of at least
one the liquid stream, the gas/vapor stream, gas-phase products,
the first and second flows and another flow.
[0030] In some more specific embodiments the system also includes a
first compressor for compressing at least a portion of the
gas-phase products.
[0031] In some more specific embodiments the system also includes a
first compressor for compressing at least a portion of the
gas/vapor stream.
[0032] In some more specific embodiments the system also includes a
first compressor for compressing at least a portion of the first
flow.
[0033] In some more specific embodiments the system also includes a
first compressor for compressing at least a portion of the second
flow.
[0034] In some more specific embodiments the system also includes a
first chiller for cooling at least a portion of the first flow.
[0035] In some more specific embodiments the system also includes a
first chiller for cooling at least a portion of the second
flow.
[0036] In some more specific embodiments the transfer of heat
energy includes mixing at least a portion of the at least two
streams or flows between which the heat is transferred.
[0037] In some more specific embodiments the transfer of heat
energy includes exchanging heat energy without mixing the at least
two streams or flows between which the heat is transferred.
[0038] In some more specific embodiments the system also includes a
turbine, for expanding at least a portion of the gas/vapor stream,
coupled to the first gas/liquid separator to receive at least a
portion of the gas/vapor stream.
[0039] In some more specific embodiments the system also includes a
turbine through which at least a portion of the second flow passes,
the turbine coupled to receive at least a portion of the second
flow.
[0040] In some more specific embodiments the system also includes
at least one other gas/liquid separator for separating at least one
of a liquid or a gas/vapor stream within the system.
[0041] In some more specific embodiments the system also includes
another condenser for further condensing at least a portion of the
liquid stream.
[0042] In some more specific embodiments the system also includes
another condenser for condensing at least a portion of the
gas/vapor stream.
[0043] In some more specific embodiments the system also includes
another expander for expanding and swirling at least a portion of
the gas-phase products.
[0044] Other aspects and features of the present invention will
become apparent, to those ordinarily skilled in the art, upon
review of the following description of the specific embodiments of
the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0045] For a better understanding of the present invention, and to
show more clearly how it may be carried into effect, reference will
now be made, by way of example, to the accompanying drawings, which
illustrate aspects of embodiments of the present invention and in
which:
[0046] FIG. 1 is a schematic drawing of a low-temperature gas
mixture separation system according to a first embodiment of the
invention;
[0047] FIG. 2 is a schematic drawing of a low-temperature gas
separation apparatus shown in FIG. 1;
[0048] FIG. 3 is a schematic drawing of a low-temperature gas
mixture separation system according to a second embodiment of the
invention;
[0049] FIG. 4 is a schematic drawing of a low-temperature gas
mixture separation system according to a third embodiment of the
invention;
[0050] FIG. 5 is a schematic drawing of a low-temperature gas
mixture separation system according to a fourth embodiment of the
invention;
[0051] FIG. 6 is a schematic drawing of a low-temperature gas
mixture separation system according to a fifth embodiment of the
invention;
[0052] FIG. 7 is a schematic drawing of a low-temperature gas
mixture separation system according to a sixth embodiment of the
invention;
[0053] FIG. 8 is a schematic drawing of a low-temperature gas
mixture separation system according to a seventh embodiment of the
invention;
[0054] FIG. 9 is a schematic drawing of a low-temperature gas
mixture separation system according to an eighth embodiment of the
invention;
[0055] FIG. 10 is a schematic drawing of a low-temperature gas
mixture separation system according to a ninth embodiment of the
invention;
[0056] FIG. 11 is a schematic drawing of a low-temperature gas
mixture separation system according to a tenth embodiment of the
invention;
[0057] FIG. 12 is a schematic drawing of a low-temperature gas
mixture separation system according to an eleventh embodiment of
the invention;
[0058] FIG. 13 is a schematic drawing of a low-temperature gas
mixture separation system according to a twelfth embodiment of the
invention;
[0059] FIG. 14 is a schematic drawing of a low-temperature gas
mixture separation system according to a thirteenth embodiment of
the invention;
[0060] FIG. 15 is a schematic drawing of a low-temperature gas
mixture separation system according to a fourteenth embodiment of
the invention;
[0061] FIG. 16 is a schematic drawing of a low-temperature gas
mixture separation system according to a fifteenth embodiment of
the invention;
[0062] FIG. 17 is a schematic drawing of a low-temperature gas
mixture separation system according to a sixteenth embodiment of
the invention;
[0063] FIG. 18 is a schematic drawing of a low-temperature gas
mixture separation system according to a seventeenth embodiment of
the invention;
[0064] FIG. 19 is a schematic drawing of a low-temperature gas
mixture separation system according to an eighteenth embodiment of
the invention;
[0065] FIG. 20 is a schematic drawing of a low-temperature gas
mixture separation system according to a nineteenth embodiment of
the invention;
[0066] FIG. 21 is a schematic drawing of a low-temperature gas
mixture separation system according to a twentieth embodiment of
the invention;
[0067] FIG. 22 is a schematic drawing of a low-temperature gas
mixture separation system according to a twenty-first embodiment of
the invention; and
[0068] FIG. 23 is a schematic drawing of a low-temperature gas
mixture separation system according to a twenty-second embodiment
of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0069] In contrast to known systems and methods for low-temperature
gas mixture separation, some embodiments of the present invention
provide a system for low-temperature gas mixture separation that
recycles energy and reduces power consumption by re-circulating
heated and/or cooled flows (e.g. gas, liquid and mixed-phase flows)
within the system. Accordingly, in some embodiments efficiency is
somewhat improved, as compared to comparable systems that do not
include the re-circulation of heat energy. In some embodiments the
heat energy that is re-circulated is a combination of heat added to
the system (i.e. inputs to the system) and heat released within the
system (i.e. byproducts from within the system) that are
subsequently recovered. In particular, some systems and methods
provided in accordance with embodiments of the invention are suited
for separating the constituent components of natural gas and other
hydrocarbon gas mixtures.
[0070] In accordance with some embodiments of the invention, a
method of low-temperate gas mixture separation includes expansion
of a gas mixture without doing mechanical work (i.e. adiabatically
expanding the gas mixture), which thereby cools and lowers the
pressure of the gas mixture, a step that does not require an
addition of energy into the system. Expanding a gas mixture without
doing mechanical work can be accomplished by passing the gas
mixture through a Joules-Thompson valve or similar device having an
expansion valve (or converging-diverging nozzle) that restricts the
flow of gas entering an expansion chamber. In accordance with some
embodiments of the invention, the gas mixture is also swirled as it
enters the gas expanding apparatus. As the swirling gas mixture
expands heavier components of the mixture are forced away from a
center axis around which the gas mixture is swirling while the
lighter components remain near to the center axis. Given the
spatial relationship of the heavier swirling components to those of
the lighter swirling components, the mixture flow is separated into
at least two flows, a first flow that primarily includes the
heavier components and a second flow that primarily includes the
lighter components of the gas mixture. In some embodiments the
heavier components may also condense on the walls of the gas
expanding apparatus, thereby facilitating an easier segregation of
the first and second flows.
[0071] In one very specific embodiment the first flow (primarily
including the heavier components) is at least partially directed to
a rectifying tower and the second flow is at least partially
directed through a heat-exchanger in order to lower the temperature
of an input gas mixture stream. Additionally, in some embodiments
the gas-phase products produced in the rectifying tower are
compressed, chilled and mixed with the input gas mixture before the
input gas mixture arrives at the heat-exchanger.
[0072] In another very specific embodiment the first flow is at
least partially directed to a rectifying tower and the second flow
is at least partially mixed with the gas-phase products produced in
the rectifying tower. Additionally, in some embodiments the
combination of the gas-phase products and the second flow are at
least partially directed through a heat-exchanger in order to lower
the temperature of an input gas mixture stream.
[0073] In another very specific embodiment the first flow is at
least partially mixed with an input gas mixture stream, before the
input gas mixture stream is expanded. Additionally, in some
embodiments first flow is at least partially directed through a
heat-exchanger in order to lower the temperature of an input gas
mixture stream. In even more specific embodiments the first flow is
also compressed and further chilled before being mixed with the
input gas stream. In some such embodiments the second flow (i.e.
the lighter flow) is outputted from the system alone or in a
suitable combination with some gas-phase products produced
elsewhere in the system.
[0074] Referring to FIG. 1, shown is a schematic drawing of a
low-temperature gas mixture separation system 200 according to a
first embodiment of the invention, referred to as the system 200
hereinafter for brevity. Those skilled in the art will appreciate
that the system 200 includes a suitable combination of associated
structural elements, mechanical systems, hardware, firmware and
software that is employed to support the function and operation of
the system 200; however, the system 200 is illustrated showing only
those elements necessary to describe aspects of this
embodiment.
[0075] The system 200 includes a first mixer 30, a first
heat-exchanger 32, a first chiller 34 and a gas/liquid separator 36
connected respectively in series. The first mixer 30 includes
respective first and second inputs 30a and 30b. The first input 30a
serves as an input to the system 200 as a whole as well as an input
of the first mixer 30. The second input 30b serves a feedback
input, the purpose of which is described in more detail below. The
gas/liquid separator 36 has respective first and second outputs 36a
and 36b. The first output 36a is a gas/vapor outlet and the second
output 36b is a liquid (or mixed-phase) output. In some embodiments
the gas/liquid separator 36 is a condenser.
[0076] The system also includes an expander 40 and a rectifying
tower 38. The expander 40 is coupled to receive a gas/vapor flow
from the first output 36a of the gas/liquid separator 36, whereas
the second output 36b of the gas/liquid separator 36 is coupled to
deliver a liquid (or mixed-phase) flow to the rectifying tower
38.
[0077] The expander 40 has respective first and second outputs 40a
and 40b. The first output 40a is connected to deliver a first flow,
of heavier components, to the rectifying tower 38. The second
output 40b is coupled back as an input to the first heat-exchanger
32 to cool the gas mixture entering by the first mixer 30.
[0078] The rectifying tower 38 has respective first and second
outputs 38a and 38b. The first output 38a is coupled back to the
second input 30b of the mixer 30. The system 200 also includes a
compressor 42 and a second chiller 44 connected in series between
the first output 38a of the rectifying tower and the second input
30b of the mixer 30.
[0079] Before describing the operation of the system 200, more
details about the expander 40 are provided with additional
reference to FIG. 2. The expander 40 has a tubular body with an
input end and an output end that are generally indicated by A and
B, respectively. The expander 40 includes a swirling means 41 near
the input end and a converging-diverging nozzle section 43
following the swirling means 41. In some embodiments the swirling
means 41 includes, without limitation, at least one of vanes, an
impeller, and fins. The converging-diverging nozzle section 43
flares open into a conical section 45 leading to the output end B.
A divider 47 is provided at the output end B within the conical
section 45 to facilitate the separation of output flows leading to
the respective first and second outputs 40a and 40b.
[0080] The expander 40 can be made both with flow swirling means
placed at the nozzle channel entry as shown in FIG. 2 (e.g. as
discussed in prior art references EP1131588 and U.S. Pat. No.
6,372,019) and with flow swirling means within the nozzle channel
(e.g. as discussed in prior art references EP0496128 and
WO99/01194).
[0081] With reference to FIGS. 1 and 2, the operation of the system
200 is as follows. An incoming mixture 201 of natural gas (or
another gas mixture) enters the system via the mixer 30, where it
is mixed with a feedback flow containing the compressed and cooled
gas-phase products from the rectifying tower 38. The combination of
the input natural gas and feedback gases is further cooled in the
first heat-exchanger 32. In accordance with a broad aspect of the
invention, the first heat-exchanger 32 facilitates the recycling of
heat energy, or rather, in this particular case, the recycling of
energy used to cool various flows within the system. That is, the
first heat-exchanger 32 cools the incoming natural gas mixture by
transferring heat from the natural gas mixture to a feedback flow
originating from the second output 40b of the expander 40, which
thereby lowers the temperature of the natural gas mixture.
[0082] The natural gas mixture is further cooled in the first
chiller 34 before entering into the gas/liquid separator 36. Within
the gas/liquid separator 36 the natural gas mixture is separated
into a gas/vapor stream and a liquid (or mixed-phase) stream. The
gas/vapor stream flows out of the gas/liquid separator 36 via the
first output 36a directly into the expander 40. The liquid stream
flows of the gas/liquid separator via the second output 36b
directly to the rectifying tower 38.
[0083] The rectifying tower 38 outputs gas-phase products through
the first output 38a and liquid phase products through the second
output 38b. The gas-phase products are compressed in the compressor
42 and cooled in the second chiller 44 before being mixed with the
incoming mixture 201 as described above.
[0084] With specific reference to FIG. 2, within the expander 40
the incoming gas/vapor stream is separated into a first flow and a
second flow. The natural gas mixture enters the expander 40, is
swirled by the swirling means 41, and expanded through the
converging-diverging nozzle section 43. As the swirling gas mixture
expands the heavier components of the mixture drift away from a
center axis around which the gas mixture is swirling while the
lighter components remain near to the center axis. Given the
spatial relationship of the heavier swirling components to those of
the lighter swirling components the gas mixture flow is separated
into at least the first and second flows, such that the first flow
primarily includes the heavier components and the second flow
primarily includes the lighter components. The first flow exits the
expander 40 through the first output 40a. The second flow exits the
expander 40 through the second output 40b.
[0085] More specifically, in some embodiments during the expansion
process, the temperature of the gas/vapor stream is reduced enough
to induce partial condensation of the mixture, thus forming a
condensate. The condensate drops in the field of centrifugal forces
move toward the walls of the expander 40 collecting into a liquid
(or two-phase) flow. When the gas mixture is natural gas the first
flow contains components that are heavier than methane, whereas the
second flow contains substantially more methane gas.
[0086] Moreover, due to the expansion during the swirling motion of
the mixture within the expander 40, the static pressure of the
mixture is lower than the pressure at the outputs of the expander
40, and the mixture separation within the nozzle occurs at
temperatures lower than the temperature of the mixture traveling
through the outputs. In some embodiments a deeper mixture
separation is provided due to the gas-phase product from the
rectifying tower 38 being fed back to the input mixture 201 before
the mixture is processed further in the system 200.
[0087] Referring to FIG. 3, shown is a schematic drawing of a
low-temperature gas mixture separation system 300 according to a
second embodiment of the invention, referred to as the system 300
hereinafter for brevity. The system 300 illustrated in FIG. 3 is
similar to the system 200 illustrated in FIG. 1, and accordingly,
elements common to both share common reference numerals. Moreover,
for the sake of brevity, portions of the description of FIG. 1 will
not be repeated with respect to FIG. 3. Again those skilled in the
art will appreciate that the system 300 includes a suitable
combination of associated structural elements, mechanical systems,
hardware, firmware and software that is employed to support the
function and operation of the system 300; however, the system 300
is illustrated showing only those elements necessary to describe
aspects of this embodiment of the invention.
[0088] The differences between the systems 200 and 300 are as
follows. The system 300 does not include the first mixer 30, the
first chiller 34, the second chiller 44 and the first compressor
42. The system 300 does include a second mixer 48 and a first
(throttling) valve 50. The first valve 50 is coupled between the
second output 36b of the gas/liquid separator 36 and the rectifying
tower 38. The second mixer 48 includes respective first and second
inputs that are coupled to receive and mix the gas/vapor outputs
from the expander 40 and the rectifying tower 38. The second mixer
48 also includes an output that is coupled to deliver the gas
mixture to the first heat-exchanger 32.
[0089] In operation the incoming mixture 301 is cooled in the first
heat-exchanger 32, before passing directly to the separator 36. The
liquid stream from the separator 36 is then directed through the
throttling valve 50 to the rectifying tower 38. The gas-phase
products from the rectifying tower 38 are mixed with the second
flow (primarily including the lighter components of the separation
process) from the expander 40 in the second mixer 48 to produce a
mixed feedback stream. The mixed feedback stream is then passed
through the first heat-exchanger 32 in which heat is transferred
from the incoming mixture 301 to the feedback stream, thereby
cooling the incoming mixture 301 without the addition of energy to
the system 300.
[0090] This method makes it possible to reduce required
differential pressure of the mixture in the low temperature
separation facilities.
[0091] Referring to FIG. 4, shown is a schematic drawing of a
low-temperature gas mixture separation system 400 according to a
third embodiment of the invention, referred to as the system 400
hereinafter for brevity. The system 400 illustrated in FIG. 4 is
similar to the respective systems illustrated in FIGS. 1 and 3, and
accordingly, elements common to each share common reference
numerals. Moreover, for the sake of brevity, portions of the
descriptions for FIGS. 1 and 3 will not be repeated with respect to
FIG. 4. Those skilled in the art will appreciate that the system
400 includes a suitable combination of associated structural
elements, mechanical systems, hardware, firmware and software that
is employed to support the function and operation of the system
400; however, the system 400 is illustrated showing only those
elements necessary to describe aspects of this embodiment of the
invention.
[0092] The arrangements specifically shown with respect to the
system 400 are as follows. The system 400 includes the first mixer
30, as shown in FIG. 1. The system 400 also includes the second
chiller 44 and the first compressor 42. However, the first
compressor 42 and the second chiller 44 are connected between the
first heat-exchanger 32 and the second input 30b (i.e. the feedback
input) of the first mixer 30. Moreover, the first output 40a of the
expander 40 is coupled to the first heat-exchanger 32 instead of
being coupled to the rectifying tower 38 as shown in FIG. 1.
[0093] In operation the incoming mixture 401 is mixed in the first
mixer 30 with the first flow (i.e. the flow primarily including the
heavier components of the mixture separated in the expander 40).
That is, the first flow from the first output 40a of the expander
40 is mixed with the incoming mixture 401 in order to cool the
incoming mixture 401. The mixture outputted from the first mixer 30
is then passed through the first heat-exchanger 32 to further
regulate the temperature of the incoming gas mixture. The first
heat-exchanger 32 is coupled to receive the first output 40a of the
expander 40 as a regulating inflow. By using the feedback system
energy is again conserved and efficiency can be improved.
[0094] In some embodiments the gas-phase products output from the
rectifying tower 38 are mixed with the second flow outputted from
the second output 40b of the expander 40 in the second mixer 48 and
the combined mixture cannot be outputted from the system 400.
[0095] Referring to FIG. 5, shown is a schematic drawing of a
low-temperature gas mixture separation system 500 according to a
fourth embodiment of the invention, referred to as the system 500
hereinafter for brevity. The system 500 illustrated in FIG. 5 is
similar to the respective systems illustrated in FIGS. 1 and 34,
and accordingly, elements common to each share common reference
numerals. Moreover, for the sake of brevity, portions of the
descriptions for FIGS. 1 and 34 will not be repeated with respect
to FIG. 5. Those skilled in the art will appreciate that the system
500 includes a suitable combination of associated structural
elements, mechanical systems, hardware, firmware and software that
is employed to support the function and operation of the system
500; however, the system 500 is illustrated showing only those
elements necessary to describe aspects of this embodiment of the
invention.
[0096] The arrangements specifically shown with respect to the
system 500 are as follows. The system 500 includes a second
heat-exchanger 52. The second mixer 48 and the second
heat-exchanger 52 are connected between the first output 36a of the
gas/liquid separator 36 and the input of the expander 40. The
second heat-exchanger 52 is also coupled to receive the first flow
from the first output 40a of the expander 40 before the first flow
is passed to the first heat-exchanger 32, as described with respect
to FIG. 4.
[0097] In operation the vapor stream from the separator 36 is mixed
with the gas-phase output of the rectifying tower 38 in the second
mixer 52. The output of the second mixer 48 is cooled in the second
heat-exchanger 52, before being passed through to the expander 40.
The first flow (from the first output 40a) from the expander 40 is
first sent through the second heat-exchanger 52 to cool the output
of the second mixer 48 and then sent through the first
heat-exchanger 32 to further cool the output of the first mixer 30.
The same first flow is then compressed in compressor 42, and is
then cooled in a second chiller 44 before being mixed with the
incoming gas mixture 501. The second flow (from the second output
40b of the expander 40) can be directly output from the system 500.
By using the feedback system energy is again conserved and
efficiency can be improved.
[0098] In some embodiments the system 500 facilitates a deep
purification of the second flow output from the expander 40 (i.e.
the flow primarily including lighter components of the gas
mixture). That is, when considering the processing of natural gas
the second flow may be significantly depleted of the vapor
components heavier than methane, since the first flow is mixed with
the incoming flow 501.
[0099] Referring to FIG. 6, shown is a schematic drawing of a
low-temperature gas mixture separation system 600 according to a
fifth embodiment of the invention, referred to as the system 600
hereinafter for brevity. The system 600 illustrated in FIG. 6 is
similar to the respective systems illustrated in FIGS. 1 and 3-5,
and accordingly, elements common to each share common reference
numerals. Moreover, for the sake of brevity, portions of the
descriptions for FIGS. 1 and 3-5 will not be repeated with respect
to FIG. 6. Those skilled in the art will appreciate that the system
600 includes a suitable combination of associated structural
elements, mechanical systems, hardware, firmware and software that
is employed to support the function and operation of the system
600; however, the system 600 is illustrated showing only those
elements necessary to describe aspects of this embodiment of the
invention.
[0100] The arrangements specifically shown with respect to the
system 600 are as follows. The system 600 includes a second
gas/liquid separator 60. The second gas/liquid separator 60
includes respective first and second outputs 60a and 60b that are
coupled to the second mixer 48 and the rectifying tower 38,
respectively. The system 600 also includes a second (throttling
valve 66) coupled between the second output 60b and an input to the
rectifying tower 38. The first output 40a of the expander 40 is
coupled to deliver the first flow from the expander 40 to the
second gas/liquid separator 60.
[0101] In operation, since there are two gas/liquid separators 36
and 60, liquid separation in the form of condensation is performed
twice: before and after various forms of the mixture are expanded
in the expander 40. More specifically, the first flow from the
expander 40 is sent to a second separator 60, which provides a
second vapor stream and a second liquid stream. The second liquid
stream passes through a second throttling valve 66 and into the
rectifying tower 38. A second vapor stream is mixed with the second
flow from the expander 40 in the second mixer 48. The mixture 48
produced in the second mixer 48 is then passed through the first
heat-exchanger 32 as described above.
[0102] Referring to FIG. 7, shown is a schematic drawing of a
low-temperature gas mixture separation system 700 according to a
sixth embodiment of the invention, referred to as the system 700
hereinafter for brevity. The system 700 illustrated in FIG. 7 is
similar to the respective systems illustrated in FIGS. 1 and 3-6,
and accordingly, elements common to each share common reference
numerals. Moreover, for the sake of brevity, portions of the
descriptions for FIGS. 1 and 3-6 will not be repeated with respect
to FIG. 7. Those skilled in the art will appreciate that the system
700 includes a suitable combination of associated structural
elements, mechanical systems, hardware, firmware and software that
is employed to support the function and operation of the system
700; however, the system 700 is illustrated showing only those
elements necessary to describe aspects of this embodiment of the
invention.
[0103] The arrangements specifically shown with respect to the
system 700 are as follows. The second heat-exchanger 52 is coupled
between the first throttling valve 50 and an input to the
rectifying tower 38. The second chiller 44 is coupled between the
rectifying tower 38 and the second heat-exchanger 52. More
specifically, the second chiller 44 is coupled to receive and cool
the gas-phase products from the first output 36a of the rectifying
tower 38. The second heat-exchanger 52 is also coupled to the first
mixer 30 to provide the cooled gas-phase products from the
rectifying tower 38 as a feedback input to the first mixer 30.
[0104] In operation the incoming mixture 701 is mixed with the
gas-phase products of the rectifying tower 38 as shown in FIG. 1,
however the gas-phase products are first cooled by the second
chiller 44 and the second heat-exchanger 52 before mixing with the
incoming mixture 701. In turn, the second heat-exchanger 52 heats
the first flow (i.e. the heavy output flow) from the expander 40
before the first flow is delivered into the rectifying tower 38.
This arrangement helps provide a more rational distribution of mass
and enthalpy flows in the low-temperature separation process.
[0105] Referring to FIG. 8, shown is a schematic drawing of a
low-temperature gas mixture separation system 800 according to a
seventh embodiment of the invention, referred to as the system 800
hereinafter for brevity. The system 800 illustrated in FIG. 8 is
similar to the respective systems illustrated in FIGS. 1 and 3-7,
and accordingly, elements common to each share common reference
numerals. Moreover, for the sake of brevity, portions of the
descriptions for FIGS. 1 and 3-7 will not be repeated with respect
to FIG. 8. Those skilled in the art will appreciate that the system
800 includes a suitable combination of associated structural
elements, mechanical systems, hardware, firmware and software that
is employed to support the function and operation of the system
500; however, the system 800 is illustrated showing only those
elements necessary to describe aspects of this embodiment of the
invention.
[0106] The arrangements specifically shown with respect to the
system 800 are as follows. Liquid separation by condensation is
facilitated twice before expansion in the expander 40. To that end,
the second gas/liquid separator 60 is coupled to receive the
combination of the liquid (or two phase output) from the first
gas/liquid separator 36 and the gas-phase products from the
rectifying tower 38. Moreover, the gas-phase products from the
rectifying tower 38 are first coupled through the second
heat-exchanger 52 that also receives the liquid phase (or two
phase) output of the second separator 60, so that heat energy can
be transferred between the two, thereby cooling one and heating the
other in order to recycle energy within the system 800.
[0107] The incoming mixture 801 is cooled in the first
heat-exchanger 32 and further cooled in the first chiller 34 before
entering the first gas/liquid separator 36. The liquid stream from
the separator 36 is passed through a throttling valve 50 and is
mixed with the gas-phase products of the rectifying tower 38 before
entering the second gas/liquid separator 60. The second gas/liquid
separator 60 also provides a second liquid stream, which passes
through the second heat-exchanger 52, thereby cooling the gas-phase
products and heating the second liquid stream. After passing
through the second heat-exchanger 52 the second liquid stream is
coupled into the rectifying tower 38. Elsewhere in the system, the
gas/vapor streams from the first and second separators 36 and 60
are combined in the second mixer 48 before being delivered to the
expander 40 where the mixture undergoes the process above described
with respect to FIGS. 1 and 2 to produce the first and second
flows. This method allows a deeper purification of the second flow
by removing a greater proportion of components heavier than methane
when natural gas is being processed.
[0108] Referring to FIG. 9, shown is a schematic drawing of a
low-temperature gas mixture separation system 900 according to an
eighth embodiment of the invention, referred to as the system 900
hereinafter for brevity. The system 900 illustrated in FIG. 9 is
similar to the respective systems illustrated in FIGS. 1 and 3-8,
and accordingly, elements common to each share common reference
numerals. Moreover, for the sake of brevity, portions of the
descriptions for FIGS. 1 and 3-8 will not be repeated with respect
to FIG. 9. Those skilled: in the art will appreciate that the
system 900 includes a suitable combination of associated structural
elements, mechanical systems, hardware, firmware and software that
is employed to support the function and operation of the system
900; however, the system 900 is illustrated showing only those
elements necessary to describe aspects of this embodiment of the
invention.
[0109] The arrangements specifically shown with respect to the
system 900 are as follows. The first chiller 34 precedes the first
heat-exchanger 32. A third heat-exchanger 62 is coupled in series
between the first heat-exchanger 32 and the first gas/liquid
separator 36. The third heat-exchanger 62 is also coupled to
receive a portion of the liquid (or two phase) stream from the
first gas/liquid separator 36. To that end, the second throttling
valve 66 is coupled between the second output 36b and the third
heat-exchanger 62 to prevent a reversal of flow and maintain a
forward pressure through the third heat-exchanger 62. Also, similar
to the system 500 shown in FIG. 5, the gas-phase products from the
rectifying tower 38 are combined with the gas/vapor stream from the
first gas/liquid separator 36 in the mixer 48 before expansion. To
that end, and as similar to FIG. 8, the second heat-exchanger 52 is
coupled between the first output 38a of the rectifying tower 38 and
the second mixer 48. The second heat-exchanger 52 also receives a
portion of the liquid stream from the first gas/liquid separator
36, with the first throttling valve 50 connected there between.
[0110] In operation a portion of the liquid stream from the first
gas/liquid separator 36 is used to cool the incoming mixture 901.
The incoming mixture 901 is cooled through the first chiller 34 and
then is mixed with a portion of the liquid stream from the first
gas/liquid separator 36 as described in more detail below. The
resulting mixture is further cooled in the first heat-exchanger 32
and in a third heat-exchanger 62 before entering the first
gas/liquid separator 36. As should be understood by now, the first
gas/liquid separator 36 produces a gas/vapor stream and a liquid
(or two-phase) stream. The gas/vapor stream is mixed in the second
mixer 48 with the gas-phase products from the rectifying tower 38,
and the resulting gas/vapor mixture is expanded and separated into
the first and second flows as described above with respect to FIGS.
1 and 2. The first flow is coupled into the rectifying tower 38 and
the second flow is coupled back to the first heat-exchanger 32.
Again, as for the systems described previously, the heat-exchangers
facilitate the recycling of energy within the system 900 thereby
improving the efficiency of the system 900.
[0111] Referring to FIG. 10, shown is a schematic drawing of a
low-temperature gas mixture separation system 1000 according ninth
to a ninth embodiment of the invention, referred to as the system
1000 hereinafter for brevity. The system 1000 illustrated in FIG.
10 is similar to the respective systems illustrated in FIGS. 1 and
3-9, and accordingly, elements common to each share common
reference numerals. Moreover, for the sake of brevity, portions of
the descriptions for FIGS. 1 and 3-9 will not be repeated with
respect to FIG. 10. Those skilled in the art will appreciate that
the system 1000 includes a suitable combination of associated
structural elements, mechanical systems, hardware, firmware and
software that is employed to support the function and operation of
the system 1000; however, the system 1000 is illustrated showing
only those elements necessary to describe aspects of this
embodiment of the invention.
[0112] The arrangements specifically shown with respect to the
system 1000 are as follows. The system 1000 includes a turbine 70
connected between the second output 40b of the expander 40 and the
first heat-exchanger 32. The addition of the turbine 70 effectively
modifies the expander 40 to create a turbo-expander. The system
1000 also includes a second compressor 64 connected in series
between the first compressor 42 and the second input 30b of the
first mixer 30.
[0113] In operation the second flow, coupled from the second output
40b of the expander 40, passes through the turbine 70 and is then
sent back through the first heat-exchanger 32 to the incoming
mixture 1001. In some embodiments a turbo-expander may be used to
provide additional expansion, either before or after the mixture
passes through the expander 40. Additionally, the incoming mixture
1001 is mixed with a feed back gas/vapor stream that includes
portions of the liquid stream of the first gas/liquid separator 36
and portions of the gas/vapor stream from the second gas/liquid
separator 60. The resulting mixture is then cooled in the first
heat-exchanger 32 before entering the first gas/liquid separator
36. The liquid stream of the first gas/liquid separator 36 is split
into a first portion and a second portion. The first portion passes
through a throttling valve 50 and into the rectifying tower 58. The
second portion of the first liquid stream is passed through a
second throttling valve 66 before mixing with the gas/vapor stream
of the second gas/liquid separator 60. By contrast, the gas/vapor
stream from the first gas/liquid separator 36 passes through the
second heat-exchanger 52 where it is cooled before entering second
mixer 48. The second mixer also receives the gas-phase products
from the rectifying tower 38. The output of the second mixer 48 is
then coupled into the expander 40 as described above. The first
flow from the expander 40 is directed into the second gas/liquid
separator 60. The second separator 66 also provides the liquid
stream which it produces directly to the rectifying tower 38.
[0114] By employing the turbine 70 as described with the second
flow from the expander 40 the service life of the turbine blades
(not shown) is extended because the quantity of condensate (drops)
in flow over the blades is decreased, thereby resulting in less
wear.
[0115] Referring to FIG. 11, shown is a schematic drawing of a
low-temperature gas mixture separation system 1100 according to a
tenth embodiment of the invention, referred to as the system 1100
hereinafter for brevity. The system 1100 illustrated in FIG. 11 is
similar to the respective systems illustrated in FIGS. 1 and 3-10,
and accordingly, elements common to each share common reference
numerals. Moreover, for the sake of brevity, portions of the
descriptions for FIGS. 1 and 3-10 will not be repeated with respect
to FIG. 11. Those skilled in the art will appreciate that the
system 900 includes a suitable combination of associated structural
elements, mechanical systems, hardware, firmware and software that
is employed to support the function and operation of the system
1100; however, the system 1100 is illustrated showing only those
elements necessary to describe aspects of this embodiment of the
invention.
[0116] The arrangements specifically shown with respect to the
system 1100 are as follows. Again, the first input 30a to the first
mixer 30 serves as an input to the system 1100 as well as an input
to the first mixer 30. The first compressor 42 is coupled in series
between the first mixer 30 and the first chiller 34, which is in
turn coupled in series to the first heat-exchanger 32. The first
and second outputs of the first heat-exchanger 32 are connected to
the first gas/liquid separator 36 and the second compressor 64
respectively. The second output 36b of the first gas/liquid
separator 36 is coupled to the parallel combination of first and
second throttling vales 50 and 66, which are in turn connected to
the rectifying tower 38 and the second heat-exchanger 52,
respectively. That is, the liquid (two-phase) stream from the first
gas/liquid separator is divided between the second heat-exchanger
52 and the rectifying tower. The second heat-exchanger 52 is also
coupled to receive the gas/vapor stream output of the first
gas/liquid separator before the gas/vapor stream enters the
expander.
[0117] The system 1100 is particularly useful when, in operation,
the incoming mixture 1101 enters at a relatively low differential
pressure. More specifically, the incoming mixture 1101 is mixed
with the second flow separated in the expander 40. The resulting
combined mixture is then compressed in a first compressor 42 before
being cooled in the first chiller 34 and the first heat-exchanger
32.
[0118] The liquid stream from the first gas/liquid separator 36 is
split into a first portion, which passes through a first throttling
valve 50 into the rectifying tower 38, and a second portion that
passes through the second throttling valve 66 into the second
heat-exchanger 52. After traveling through the second
heat-exchanger 52, the second portion enters the second mixer 48,
where it is mixed with the gas-phase products of the rectifying
tower 38. The combination is then fed back to the first mixer 30 to
be mixed with the incoming mixture 1101, as described above. The
gas/vapor stream 36 from the first separator is sent to the
expander 40 and undergoes the process described above with respect
to FIGS. 1 and 2.
[0119] Referring to FIG. 12, shown is a schematic drawing of a
low-temperature gas mixture separation system 1200 according to an
eleventh embodiment of the invention, referred to as the system
1200 hereinafter for brevity. The system 1200 illustrated in FIG.
12 is similar to the respective systems illustrated in FIGS. 1 and
3-11, and accordingly, elements common to each share common
reference numerals. Moreover, for the sake of brevity, portions of
the descriptions for FIGS. 1 and 3-11 will not be repeated with
respect to FIG. 12. Those skilled in the art will appreciate that
the system 1200 includes a suitable combination of associated
structural elements, mechanical systems, hardware, firmware and
software that is employed to support the function and operation of
the system 1200; however, the system 1200 is illustrated showing
only those elements necessary to describe aspects of this
embodiment of the invention.
[0120] The arrangements specifically shown with respect to the
system 1200 are as follows. The gas/vapor stream of the first
gas/liquid separator 36 is split into two streams. The first stream
is coupled into the expander 40. The second stream is coupled into
the turbine 70 that is placed in parallel with the expander 40. The
first output 40a of the expander 40 and the output of the turbine
70 meet at the second mixer 48 that is in turn coupled to the
rectifying tower 38. The second output 40b of the expander 40 and
the first output 38a of the rectifying tower meet at the third
mixer 68 that is in turn connected in series to the second
heat-exchanger 52 and the second compressor 64. The system 1200 is
suitable for situations in which it is desirable to provide
increased pressure within the system to improve the effectiveness
of the mixture separation.
[0121] In operation after mixing of the incoming mixture 1201 with
a portion of the liquid stream from the first gas/liquid separator
36, the resulting mixture is compressed in the compressor 42 and
cooled in the first chiller 34 and the first heat-exchanger 32.
Another portion of the liquid stream from the first gas/liquid
separator 36, is passed through the throttling valve 50 and into
the rectifying tower 38. The gas/vapor stream of the first
gas/liquid separator 36 is also split into two portions. The first
portion is directed into the turbine 70 and the second portion is
directed into the expander 40. The first flow from the expander 40
and the output of the turbine 70 are mixed and delivered to the
rectifying tower 38. The second flow is mixed with the gas-phase
products from the rectifying tower 38 and passes through the second
heat-exchanger 52 and compressor 64 before exiting the system.
[0122] Referring to FIG. 13, shown is a schematic drawing of a
low-temperature gas mixture separation system 1300 according to a
twelfth embodiment of the invention, referred to as the system 1300
hereinafter for brevity. The system 1300 illustrated in FIG. 13 is
similar to the respective systems illustrated in FIGS. 1 and 3-12,
and accordingly, elements common to each share common reference
numerals. Moreover, for the sake of brevity, portions of the
descriptions for FIGS. 1 and 3-12 will not be repeated with respect
to FIG. 13. Those skilled in the art will appreciate that the
system 1300 includes a suitable combination of associated
structural elements, mechanical systems, hardware, firmware and
software that is employed to support the function and operation of
the system 1300; however, the system 1300 is illustrated showing
only those elements necessary to describe aspects of this
embodiment of the invention.
[0123] The arrangements specifically shown with respect to the
system 1300 are as follows. The system 1300 includes a second
expander 80 similar in design and function to the expander 40
described above with respect to FIG. 2. Analogous to the first
expander 40, the expander 80 has respective first and second
outputs 80a and 80b. The first output 80a is connected to deliver a
first flow, of heavier components, to the second gas/liquid
separator 60, and the second output 40b is coupled to combine a
second flow, of lighter components, with the gas/vapor stream of
the second gas/liquid separator 60. The system 1300 also includes a
pump 72 and a third throttling valve 74 connected in series between
the liquid (or two-phase) stream (i.e. the second output 60b) of
the second gas/liquid separator 60 and the third heat-exchanger 62,
which is in turn coupled to the rectifying tower 38. The gas-phase
products from the rectifying tower 38 are also coupled through the
third heat-exchanger 62.
[0124] In operation the gas-phase products from the rectifying
tower 38 are cooled, expanded (in the second expander 80) and
separated, and the resulting second flow from the second expander
80 is directed, either partially or totally, back to the rectifying
tower 38.
[0125] Referring to FIG. 14, shown is a schematic drawing of a
low-temperature gas mixture separation system 1400 according to a
thirteenth embodiment of the invention, referred to as the system
1400 hereinafter for brevity. The system 1400 illustrated in FIG.
14 is similar to the respective systems illustrated in FIGS. 1 and
3-13, and accordingly, elements common to each share common
reference numerals. Moreover, for the sake of brevity, portions of
the descriptions for FIGS. 1 and 3-13 will not be repeated with
respect to FIG. 14. Those skilled in the art will appreciate that
the system 1400 includes a suitable combination of associated
structural elements, mechanical systems, hardware, firmware and
software that is employed to support the function and operation of
the system 1400; however, the system 1400 is illustrated showing
only those elements necessary to describe aspects of this
embodiment of the invention.
[0126] The arrangements specifically shown with respect to the
system 1400 are as follows. The system 1400 includes a cooling and
compression loop connected between the first output 38a of the
rectifying tower 38 and the input of the second gas/liquid
separator 60 that includes a third heat-exchanger 76, the second
compressor 64 and second chiller 44 connected in series. The output
of the second chiller 44 is then connected in a feedback loop
through the third heat-exchanger 76. The first output 60a (i.e. the
gas/vapor output) of the second gas/liquid separator 60 is coupled
to the second expander 80. The first output 80a (containing the
heavier of the separated components from the expansion and
separation process) of the expander 80 is coupled to the rectifying
tower 38 and the second output 80b is combined with the second
output 40b of the expander 40.
[0127] In operation the gas-phase products from the rectifying
tower 38 are chilled and compressed in the aforementioned cooling
and compression loop. Specifically, the gas-phase products from the
rectifying tower 38 are cooled in the heat-exchanger 76, compressed
in the compressor 64, cooled in the chiller 44, and further cooled
in second heat-exchanger 62 before entering into the second
gas/liquid separator 60. The liquid stream from the second
gas/liquid separator 60 also passes through the second
heat-exchanger 162 before entering into the rectifying tower 38.
The operation of the rest of the system 1400 is analogous to that
of the system 1300 illustrated in FIG. 13.
[0128] Referring to FIG. 15, shown is a schematic drawing of a
low-temperature gas mixture separation system 1500 according to a
fourteenth embodiment of the invention, referred to as the system
1500 hereinafter for brevity. The system 1500 illustrated in FIG.
15 is similar to the respective systems illustrated in FIGS. 1 and
3-14, and accordingly, elements common to each share common
reference numerals. Moreover, for the sake of brevity, portions of
the descriptions for FIGS. 1 and 3-14 will not be repeated with
respect to FIG. 15. Those skilled in the art will appreciate that
the system 1500 includes a suitable combination of associated
structural elements, mechanical systems, hardware, firmware and
software that is employed to support the function and operation of
the system 1500; however, the system 1500 is illustrated showing
only those elements necessary to describe aspects of this
embodiment of the invention.
[0129] The arrangements specifically shown with respect to the
system 1500 are as follows. In system 1500 the first output 38a of
the rectifying tower 38 is coupled to the input of second expander
80 via the second chiller 44. The first output 80a of the expander
80 is coupled to the second gas/liquid separator 60. In turn, as
also shown in FIG. 14, the liquid (or two-phase) output of the
separator 60 is coupled into the rectifying tower 38.
[0130] In operation the gas-phase products from the rectifying
tower 38 are expanded within the second expander 80 to separate
heavy and light components from one another as described above with
respect to FIG. 2. The first flow (containing the heavier
components) from the first output 80a of the second expander 80
passes into the second gas/liquid separator 60. The liquid (or
two-phase) output is pumped into the rectifying tower 38 through
pump 72 and the third throttling valve 74. The second output 80b of
the expander 80 is combined with the gas/vapor stream output from
the second separator 60 and the second output 40b of the expander
40. The resulting mixture is fed back to the first heat-exchanger
32 to cool the incoming mixture 1501. The incoming mixture 1501,
having been mixed with a feedback flow as described previously, is
also compressed before entering the first gas/liquid separator 36.
The remaining operations are similar to the systems described
previously.
[0131] Referring to FIG. 16, shown is a schematic drawing of a
low-temperature gas mixture separation system 1600 according to a
fifteenth embodiment of the invention, referred to as the system
1600 hereinafter for brevity. The system 1600 illustrated in FIG.
16 is similar to the respective systems illustrated in FIGS. 1 and
3-15, and accordingly, elements common to each share common
reference numerals. Moreover, for the sake of brevity, portions of
the descriptions for FIGS. 1 and 3-15 will not be repeated with
respect to FIG. 16. Those skilled in the art will appreciate that
the system 1600 includes a suitable combination of associated
structural elements, mechanical systems, hardware, firmware and
software that is employed to support the function and operation of
the system 1600; however, the system 1600 is illustrated showing
only those elements necessary to describe aspects of this
embodiment of the invention.
[0132] The arrangements specifically shown with respect to the
system 1600 are as follows. Unlike the system 1500, the system 1600
only includes the first gas/liquid separator 36. The third
heat-exchanger 62 is connected in series between the first output
38a of the rectifying tower 38 and the input of the second expander
80. The first output 80a of the expander 80 is fed back and coupled
through the third heat-exchanger 62 via the third throttling valve
74 and through the second heat-exchanger 52, which is in turn
coupled back to the first mixer 30
[0133] In operation the first flow separated in the second expander
80 travels through the third and second heat-exchangers 62 and 52,
respectively before being combined with the incoming mixture 1601.
The liquid (or two-phase) output stream from the first gas/liquid
separator 36 is also combined with the first flow separated in the
second expander 80 before the second heat-exchanger 52. The second
throttling valve 66 prevents back flow of the liquid output stream
to the first gas/liquid separator 36. The remaining elements
operate as discussed with respect to FIG. 15.
[0134] Referring to FIG. 17, shown is a schematic drawing of a
low-temperature gas mixture separation system 1700 according to a
sixteenth embodiment of the invention, referred to as the system
1700 hereinafter for brevity. The system 1700 illustrated in FIG.
17 is similar to the respective systems illustrated in FIGS. 1 and
3-16, and accordingly, elements common to each share common
reference numerals. Moreover, for the sake of brevity, portions of
the descriptions for FIGS. 1 and 3-16 will not be repeated with
respect to FIG. 17. Those skilled in the art will appreciate that
the system 1700 includes a suitable combination of associated
structural elements, mechanical systems, hardware, firmware and
software that is employed to support the function and operation of
the system 1700; however, the system 1700 is illustrated showing
only those elements necessary to describe aspects of this
embodiment of the invention.
[0135] The arrangements specifically shown with respect to the
system 1700 are as follows. The system 1700 includes four
gas/liquid separators, namely, the first and second gas/liquid
separators 36 and 60 and additionally third and fourth gas/liquid
separators 82 and 84. The first and second gas/liquid separators 36
and 60 are connected such that the gas/vapor output of the first
gas/liquid separator 36 is coupled into the second gas/liquid
separator 60. The turbine 70 and second mixer 48 are connected
there between, as illustrated in FIG. 17. The liquid outputs of the
first and second gas/liquid separators 36 and 60 are combined and
coupled to the third separator 82. The liquid output of the third
separator 82 is coupled to the fourth separator 84 via the second
heat-exchanger 52. The liquid output of the fourth gas/liquid
separator 84 is coupled to the rectifying tower 38 and the
gas/vapor output is coupled through the second mixer 48 to the
second gas/liquid separator 60 along with the gas/vapor output of
the third gas/liquid separator 82. The gas/vapor output stream of
the second gas/liquid separator 60 is coupled into the expander 40.
The compressor stage of the turbo-expander can be used as
compressor 42, and this scheme makes it possible to improve power
consumption in the process of low-temperature separation.
[0136] In operation the incoming mixture 1701 is cooled by the
series combination of the first and second heat-exchangers 32 and
52 before entering the first gas/liquid separator 36. The liquid
streams from the first and second gas/liquid separator 36, 60 are
combined and directed into the third gas/liquid separator 82 along
with the first flow produce by the expander 40. The third
gas/liquid separator 82 produces a liquid stream that is used as a
coolant in the second heat-exchanger 52 before being further
processed in the fourth gas/liquid separator 84. The liquid stream
produced by the fourth gas/liquid separator 84 is then delivered to
the rectifying tower 38. The gas/vapor streams from the third and
fourth gas/liquid separators 82 and 84 are combined and fed back to
the second gas/liquid separator 60 along with the gas/vapor stream
from the first gas/liquid separator.
[0137] Referring to FIG. 18, shown is a schematic drawing of a
low-temperature gas mixture separation system 1800 according to a
seventeenth embodiment of the invention, referred to as the system
1800 hereinafter for brevity. The system 1800 illustrated in FIG.
18 is similar to the respective systems illustrated in FIGS. 1 and
3-17, and accordingly, elements common to each share common
reference numerals. Moreover, for the sake of brevity, portions of
the descriptions for FIGS. 1 and 3-17 will not be repeated with
respect to FIG. 18. Those skilled in the art will appreciate that
the system 1800 includes a suitable combination of associated
structural elements, mechanical systems, hardware, firmware and
software that is employed to support the function and operation of
the system 1800; however, the system 1800 is illustrated showing
only those elements necessary to describe aspects of this
embodiment of the invention.
[0138] The arrangements specifically shown with respect to the
system 1800 are as follows. The liquid stream output 36b of the
first gas/liquid separator 36 is coupled to both the rectifying
tower 38 and the third heat-exchanger 62. The third heat-exchanger
62 is coupled in series between the first heat-exchanger 32 and the
first gas/liquid separator 36. Moreover, the third heat exchange 62
couples the liquid stream output 36b back to the first mixer 30 via
the first compressor 42 and the second chiller 44.
[0139] In operation a portion of the liquid stream from the first
gas/liquid separator 36 is used to cool the incoming mixture 1701,
as shown by example in FIG. 18. The incoming mixture 1701 is cooled
through the first chiller 34 and then mixed with a portion of the
liquid stream from the first gas/liquid separator 36. That portion
of the liquid stream, however, is first used as a coolant in the
third heat-exchanger 62 and then compressed and chilled before
being added to the incoming mixture 1701. The remaining portions of
the system operate as described with respect to FIG. 3.
[0140] Referring to FIG. 19, shown is a schematic drawing of a
low-temperature gas mixture separation system 1900 according to an
eighteenth embodiment of the invention, referred to as the system
1900 hereinafter for brevity. The system 1900 illustrated in FIG.
19 is similar to the respective systems illustrated in FIGS. 1 and
3-18, and accordingly, elements common to each share common
reference numerals. Moreover, for the sake of brevity, portions of
the descriptions for FIGS. 1 and 3-18 will not be repeated with
respect to FIG. 19. Those skilled in the art will appreciate that
the system 1900 includes a suitable combination of associated
structural elements, mechanical systems, hardware, firmware and
software that is employed to support the function and operation of
the system 1900; however, the system 1900 is illustrated showing
only those elements necessary to describe aspects of this
embodiment of the invention.
[0141] The arrangements specifically shown with respect to the
system 1900 are as follows. The gas/vapor stream of the first
gas/liquid separator 36 is split into two streams. The first stream
is coupled into the expander 40. The second stream is coupled into
the turbine 70 that is placed in parallel with the expander 40. The
first output 40a of the expander 40 and the output of the turbine
70 are coupled into the rectifying tower 38. The second output 40b
of the expander 40 and the first output 38a of the rectifying tower
meet at the second mixer 48 that is in turn connected in series to
the first heat-exchanger 32. The system 1900 is suitable for
situations in which it is desirable to provide increased pressure
within the system to improve the effectiveness of the mixture
separation.
[0142] In operation incoming mixture 1901 is cooled in the first
heat-exchanger 32 and separated in the first gas/liquid separator
36. The liquid stream 16 passes through a valve 42 and into the
rectifying tower 18. Before expansion, the gas/vapor stream
produced by the first gas/liquid separator 36 is separated into at
least two flows, one of which is pumped through a turbo-expander
turbine 70 and directed to the rectifying tower 38, and the other
flow is expanded through the expander 40. The first flow from the
expander 40 is sent to the rectifying tower 38, while the second
flow is mixed with the gas-phase products from the rectifying tower
38, the combination of which is sent through the first
heat-exchanger 32 and outputted after being compressed in the first
compressor 42. This method is applicable for deeper purification of
the mixture and for substantially removing heavier components from
the mixture.
[0143] Referring to FIG. 20, shown is a schematic drawing of a
low-temperature gas mixture separation system 2000 according to a
nineteenth embodiment of the invention, referred to as the system
2000 hereinafter for brevity. The system 2000 illustrated in FIG.
20 is similar to the respective systems illustrated in FIGS. 1 and
3-19, and accordingly, elements common to each share common
reference numerals. Moreover, for the sake of brevity, portions of
the descriptions for FIGS. 1 and 3-19 will not be repeated with
respect to FIG. 20. Those skilled in the art will appreciate that
the system 2000 includes a suitable combination of associated
structural elements, mechanical systems, hardware, firmware and
software that is employed to support the function and operation of
the system 2000; however, the system 2000 is illustrated showing
only those elements necessary to describe aspects of this
embodiment of the invention.
[0144] The arrangements specifically shown with respect to the
system 2000 are as follows. The system 2000 is almost identical to
the system 1900 with the exception that the compressor 42 is not
included. In operation this system 2000, as well as system 1900,
may facilitates improved efficiency of the turbo-expander turbine
70, thus providing for deeper gas cooling in the turbine 70 and
allowing for a greater compression ratio.
[0145] Referring to FIG. 21, shown is a schematic drawing of a
low-temperature gas mixture separation system 2100 according to a
twentieth embodiment of the invention, referred to as the system
2100 hereinafter for brevity. The system 2000 illustrated in FIG.
21 is similar to the respective systems illustrated in FIGS. 1 and
3-20, and accordingly, elements common to each share common
reference numerals. Moreover, for the sake of brevity, portions of
the descriptions for FIGS. 1 and 3-20 will not be repeated with
respect to FIG. 20. Those skilled in the art will appreciate that
the system 2100 includes a suitable combination of associated
structural elements, mechanical systems, hardware, firmware and
software that is employed to support the function and operation of
the system 2100; however, the system 2100 is illustrated showing
only those elements necessary to describe aspects of this
embodiment of the invention.
[0146] The arrangements specifically shown with respect to the
system 2100 are as follows. The first output 36a of the first
gas/liquid separator 36 is split between the turbine 70, the
expander 40 and the third mixer 68. The third mixer 68 also
receives the first flow from the expander 40 and the gas-phase
products from the rectifying tower 38.
[0147] In operation the gas/vapor stream produced by the first
separator 36 is divided into three portions that are passed to the
turbine 70, the expander 40 and the third mixer 68, respectively.
The remaining components operate as discussed with reference to
FIGS. 19 and 20. This method makes it possible to stabilize the
mass flow rate through the turbo-expander turbine 70 in case of
variations in the incoming mixture 2101.
[0148] Referring to FIG. 22, shown is a schematic drawing of a
low-temperature gas mixture separation system 2200 according to a
twenty-first embodiment of the invention, referred to as the system
2200 hereinafter for brevity. The system 2200 illustrated in FIG.
15 is similar to the respective systems illustrated in FIGS. 1 and
3-21, and accordingly, elements common to each share common
reference numerals. Moreover, for the sake of brevity, portions of
the descriptions for FIGS. 1 and 3-21 will not be repeated with
respect to FIG. 22. Those skilled in the art will appreciate that
the system 2200 includes a suitable combination of associated
structural elements, mechanical systems, hardware, firmware and
software that is employed to support the function and operation of
the system 2200; however, the system 2200 is illustrated showing
only those elements necessary to describe aspects of this
embodiment of the invention.
[0149] The arrangements specifically shown with respect to the
system 2200 are as follows. The second output (i.e. the liquid
output) 36b of the first gas/liquid separator and the first output
40a of the expander 40 are coupled into the second mixer 48, which
is in turn coupled to the first heat-exchanger 32.
[0150] In operation the resulting combination of the liquid output
of the first gas/liquid separator 26 and the first flow from the
expander 40 is used to cool the incoming mixture 2201 within the
first heat-exchanger 32, as well as being added to the incoming
mixture 2201 within the first mixer 30. This method can be
effective in cases where the gas-phase products produced by the
rectifying tower 38 contain relatively light components from the
incoming mixture 2201. For example, when processing natural gas the
gas-phase products produced by the rectifying tower 38 may have
very low amounts of components that are heavier than methane.
[0151] Referring to FIG. 23, shown is a schematic drawing of a
low-temperature gas mixture separation system 2300 according to a
twenty-second embodiment of the invention, referred to as the
system 2300 hereinafter for brevity. The system 2300 illustrated in
FIG. 23 is similar to the respective systems illustrated in FIGS. 1
and 3-22, and accordingly, elements common to each share common
reference numerals. Moreover, for the sake of brevity, portions of
the descriptions for FIGS. 1 and 3-22 will not be repeated with
respect to FIG. 23. Those skilled in the art will appreciate that
the system 2300 includes a suitable combination of associated
structural elements, mechanical systems, hardware, firmware and
software that is employed to support the function and operation of
the system 2300; however, the system 2300 is illustrated showing
only those elements necessary to describe aspects of this
embodiment of the invention.
[0152] The arrangements specifically shown with respect to the
system 2300 are as follows. A portion of the second output 36b of
the first gas/liquid separator 36 and the first output 40a of the
expander 40 are connected and coupled through the second and the
third heat-exchangers 52 and 62. The first output 38a of the
rectifying tower 38 is also coupled with the corresponding output
of the third heat-exchanger 62 and then coupled into the first
compressor 42. The first compressor 42 is then coupled in series to
through the second chiller 44 to the first mixer 30 that also
accepts the incoming mixture 2301.
[0153] In operation a portion of the liquid output from the first
gas/liquid separator 36 is combined with the first flow produced by
the expander 40. The combination is used to chill the gas/vapor
stream from the first gas/liquid separator 36 in the second
heat-exchanger 52 and the incoming mixture 2301 in the third
heat-exchanger 62 before being combined with the incoming mixture
2301 in the mixer 30. The system 2300 is suitable for processing
gas mixtures in which the concentration of the target components is
low in the incoming mixture.
[0154] What has been described is merely illustrative of the
application of the principles of the invention. Numerous
modifications and variations of the present invention are possible
in light of the above teachings. It is therefore to be understood
that within the scope of the following claims, the invention may be
practiced otherwise than as specifically described herein.
* * * * *