Mixed refrigerant system and method
阅读说明:本技术 混合制冷剂系统和方法 (Mixed refrigerant system and method ) 是由 D.A.小杜科特 T.古斯哈纳斯 于 2018-09-21 设计创作,主要内容包括:一种用于用混合制冷剂来冷却气体的系统,包括热交换器,其接收并冷却气体的进料,从而产生产物。该系统包括混合制冷剂处理系统,其具有压缩装置和后冷却器以及低压蓄积器和高压蓄积器。冷蒸气分离器从高压蓄积器接收蒸气,并具有蒸气出口和液体出口。来自冷蒸气分离器蒸气出口的蒸气被冷却、膨胀并被引导至热交换器的主制冷通道。来自冷蒸气分离器的液体出口的液体被过冷却、膨胀并被引导至主制冷通道。来自低压蓄积器的液体被过冷却、膨胀并被引导至主制冷通道。来自高压蓄积器的液体被过冷却、膨胀并被引导至主制冷通道。(A system for cooling a gas with a mixed refrigerant includes a heat exchanger that receives and cools a feed of the gas to produce a product. The system includes a mixed refrigerant processing system having a compression device and an aftercooler and a low pressure accumulator and a high pressure accumulator. The cold vapor separator receives vapor from the high pressure accumulator and has a vapor outlet and a liquid outlet. Vapor from the cold vapor separator vapor outlet is cooled, expanded and directed to the main refrigeration passage of the heat exchanger. Liquid from the liquid outlet of the cold vapor separator is subcooled, expanded and directed to the main refrigeration passage. Liquid from the low pressure accumulator is subcooled, expanded and directed to the main refrigeration passage. Liquid from the high pressure accumulator is subcooled, expanded, and directed to the main refrigeration passage.)
1. A system for cooling a gas with a mixed refrigerant, comprising:
a) a heat exchanger comprising a cooling channel having an inlet and an outlet, the inlet configured to receive a feed of gas and a product exiting the heat exchanger through the outlet, the heat exchanger further comprising a main refrigeration channel, a pre-cooling liquid channel, a high pressure vapor channel, a high pressure liquid channel, a cold separator vapor channel, and a cold separator liquid channel;
b) a first stage compression device having an inlet in fluid communication with an outlet of the main refrigeration passage;
c) a first stage aftercooler having an inlet in fluid communication with the outlet of the first stage compression device, and an outlet;
d) a low pressure accumulator having an inlet in fluid communication with the outlet of the first stage aftercooler, and having a liquid outlet in fluid communication with the pre-cooled liquid passage of the heat exchanger, and a vapor outlet;
e) a second stage compression device having an inlet in fluid communication with the vapor outlet of the low pressure accumulator, and an outlet;
f) a second stage aftercooler having an inlet in fluid communication with the outlet of the second stage compression device, and an outlet;
g) a high pressure accumulator having an inlet in fluid communication with the outlet of the second stage after cooler and having a liquid outlet in fluid communication with the high pressure liquid passage of the heat exchanger and a vapor outlet in fluid communication with the high pressure vapor passage of the heat exchanger;
h) a cold vapor separator having an inlet in fluid communication with the high pressure vapor passage of the heat exchanger, a vapor outlet in fluid communication with the cold separator vapor passage of the heat exchanger, and a liquid outlet in fluid communication with the cold separator liquid passage of the heat exchanger;
i) a first expansion device having an inlet in fluid communication with the high pressure liquid passage of the heat exchanger, and an outlet;
j) a medium temperature separation device having an inlet in fluid communication with the outlet of the first expansion device, a vapor outlet in fluid communication with the main refrigeration passage, and a liquid outlet in fluid communication with the main refrigeration passage;
k) a second expansion device having an inlet in fluid communication with the cold separator liquid passage of the heat exchanger, and an outlet;
l) a CVS temperature separation device having an inlet in fluid communication with the outlet of the second expansion device, a vapor outlet in fluid communication with the main refrigeration passage, and a liquid outlet in fluid communication with the main refrigeration passage;
m) a third expansion device having an inlet in fluid communication with the cold separator vapor passage of the heat exchanger and an outlet in fluid communication with the main refrigeration passage; and
n) a fourth expansion device having an inlet in fluid communication with the pre-cooled liquid passage of the heat exchanger and an outlet in fluid communication with at least one of the intermediate temperature separation device, the CVS temperature separation device, and the main refrigeration passage.
2. The system of claim 1, wherein the first and second compression stages are stages of a single compressor.
3. The system of claim 1, wherein the medium temperature, CVS temperature, and cold temperature separation device is a riser.
4. The system of claim 1, further comprising a warm temperature separation device having an inlet in fluid communication with the outlet of the fourth expansion device, a vapor outlet in fluid communication with the main refrigeration passage, and a liquid outlet in fluid communication with the main refrigeration passage.
5. The system of claim 1, further comprising a cold temperature separation device having an inlet in fluid communication with the outlet of the third expansion device, a vapor outlet in fluid communication with the main refrigeration passage, and a liquid outlet in fluid communication with the main refrigeration passage.
6. The system of claim 1, wherein the outlet of the fourth expansion device is in fluid communication with only the medium temperature separation device.
7. The system of claim 1, wherein an outlet of the fourth expansion device is in fluid communication with only the CVS temperature separation device.
8. The system of claim 1 wherein the outlet of the fourth expansion device is in fluid communication with only the main refrigeration passage.
9. The system of claim 1, wherein the outlet of the fourth expansion device is in fluid communication with both the medium and CVS temperature separation devices.
10. The system of claim 1 wherein the outlet of the fourth expansion device is in fluid communication with both the intermediate temperature separation device and the main refrigeration passage.
11. The system of claim 1 wherein the outlet of the fourth expansion device is in fluid communication with both the CVS temperature separator and the main refrigeration path.
12. The system of claim 1, wherein an outlet of the fourth expansion device is in fluid communication with a medium and CVS temperature separation device and a main refrigeration passage.
13. A system for cooling a gas with a mixed refrigerant, comprising:
a) a heat exchanger comprising a cooling channel having an inlet and an outlet, the inlet configured to receive a feed of gas and a product exiting the heat exchanger through the outlet, the heat exchanger further comprising a main refrigeration channel, a pre-cooling liquid channel, a high pressure vapor channel, a high pressure liquid channel, a cold separator vapor channel, and a cold separator liquid channel;
b) a first stage compression device having an inlet in fluid communication with an outlet of the main refrigeration passage;
c) a first stage aftercooler having an inlet in fluid communication with the outlet of the first stage compression device, and an outlet;
d) a low pressure accumulator having an inlet in fluid communication with the outlet of the first stage aftercooler, and having a liquid outlet in fluid communication with the pre-cooled liquid passage of the heat exchanger, and a vapor outlet;
e) a second stage compression device having an inlet in fluid communication with the vapor outlet of the low pressure accumulator, and an outlet;
f) a second stage aftercooler having an inlet in fluid communication with the outlet of the second stage compression device, and an outlet;
g) a high pressure accumulator having an inlet in fluid communication with the outlet of the second stage after cooler and having a liquid outlet in fluid communication with the high pressure liquid passage of the heat exchanger and a vapor outlet in fluid communication with the high pressure vapor passage of the heat exchanger;
h) a cold vapor separator having an inlet in fluid communication with the high pressure vapor passage of the heat exchanger, a vapor outlet in fluid communication with the cold separator vapor passage of the heat exchanger, and a liquid outlet in fluid communication with the cold separator liquid passage of the heat exchanger;
i) a first expansion device having an inlet in fluid communication with the high pressure liquid passage of the heat exchanger and an outlet in fluid communication with the main refrigeration passage;
j) a second expansion device having an inlet in fluid communication with the cold separator liquid passage of the heat exchanger and an outlet in fluid communication with the main refrigeration passage;
k) a third expansion device having an inlet in fluid communication with the cold separator vapor passage of the heat exchanger and an outlet in fluid communication with the main refrigeration passage; and
l) a fourth expansion device having an inlet in fluid communication with the pre-cooled liquid passage of the heat exchanger and an outlet in fluid communication with the main refrigeration passage.
14. The system of claim 13, further comprising a medium temperature separation device having an inlet in fluid communication with the outlet of the first expansion device, a vapor outlet in fluid communication with the main refrigeration passage, and a liquid outlet in fluid communication with the main refrigeration passage.
15. The system of claim 13, further comprising a CVS temperature separation device having an inlet in fluid communication with the outlet of the second expansion device, a vapor outlet in fluid communication with the main refrigeration passage, and a liquid outlet in fluid communication with the main refrigeration passage.
16. The system of claim 13, further comprising a cold temperature separation device having an inlet in fluid communication with the outlet of the third expansion device, a vapor outlet in fluid communication with the main refrigeration passage, and a liquid outlet in fluid communication with the main refrigeration passage.
17. The system of claim 13, further comprising a warm temperature separation device having an inlet in fluid communication with the outlet of the fourth expansion device, a vapor outlet in fluid communication with the main refrigeration passage, and a liquid outlet in fluid communication with the main refrigeration passage.
18. A system for cooling a gas with a mixed refrigerant, comprising:
a) a heat exchanger comprising a cooling channel having an inlet and an outlet, the inlet configured to receive a feed of gas and a product exiting the heat exchanger through the outlet, the heat exchanger further comprising a main refrigeration channel, a high pressure vapor channel, a high pressure liquid channel, a cold separator vapor channel, and a cold separator liquid channel;
b) a compression device having an inlet in fluid communication with the outlet of the main refrigeration passage;
c) an aftercooler having an inlet in fluid communication with the outlet of the compression device, and an outlet;
d) an accumulator having an inlet in fluid communication with the outlet of the aftercooler, and having a liquid outlet in fluid communication with the high pressure liquid passage of the heat exchanger and a vapor outlet in fluid communication with the high pressure vapor passage of the heat exchanger;
e) a cold vapor separator having an inlet in fluid communication with the high pressure vapor passage of the heat exchanger, a vapor outlet in fluid communication with the cold separator vapor passage of the heat exchanger, and a liquid outlet in fluid communication with the cold separator liquid passage of the heat exchanger;
f) a first expansion device having an inlet in fluid communication with the high pressure liquid passage of the heat exchanger, and an outlet;
g) a medium temperature separation device having an inlet in fluid communication with the outlet of the first expansion device, a vapor outlet in fluid communication with the main refrigeration passage, and a liquid outlet in fluid communication with the main refrigeration passage;
h) a second expansion device having an inlet in fluid communication with the cold separator liquid passage of the heat exchanger and an outlet in fluid communication with the main refrigeration passage; and
i) a third expansion device having an inlet in fluid communication with the cold separator vapor passage of the heat exchanger and an outlet in fluid communication with the main refrigeration passage.
19. A system for cooling a gas with a mixed refrigerant, comprising:
a) a heat exchanger comprising a cooling channel having an inlet and an outlet, the inlet configured to receive a feed of gas and a product exiting the heat exchanger through the outlet, the heat exchanger further comprising a main refrigeration channel, a high pressure vapor channel, a high pressure liquid channel, a cold separator vapor channel, and a cold separator liquid channel;
b) a compression device having an inlet in fluid communication with the outlet of the main refrigeration passage;
c) an aftercooler having an inlet in fluid communication with the outlet of the compression device, and an outlet;
d) an accumulator having an inlet in fluid communication with the outlet of the aftercooler, and having a liquid outlet in fluid communication with the high pressure liquid passage of the heat exchanger and a vapor outlet in fluid communication with the high pressure vapor passage of the heat exchanger;
e) a cold vapor separator having an inlet in fluid communication with the high pressure vapor passage of the heat exchanger, a vapor outlet in fluid communication with the cold separator vapor passage of the heat exchanger, and a liquid outlet in fluid communication with the cold separator liquid passage of the heat exchanger;
f) a first expansion device having an inlet in fluid communication with the high pressure liquid passage of the heat exchanger and an outlet in fluid communication with the main refrigeration passage;
g) a second expansion device having an inlet in fluid communication with the cold separator liquid passage of the heat exchanger, and an outlet;
h) a CVS temperature separation device having an inlet in fluid communication with the outlet of the second expansion device, a vapor outlet in fluid communication with the main refrigeration passage, and a liquid outlet in fluid communication with the main refrigeration passage; and
i) a third expansion device having an inlet in fluid communication with the cold separator vapor passage of the heat exchanger and an outlet in fluid communication with the main refrigeration passage.
20. A system for cooling a gas with a mixed refrigerant, comprising:
a) a heat exchanger comprising a shell defining an interior, a cooling channel located within the interior, and having an inlet configured to receive a feed of gas and an outlet through which product exits the heat exchanger, the heat exchanger further comprising a pre-cooling liquid channel, a high pressure vapor channel, a high pressure liquid channel, a cold separator vapor channel, and a cold separator liquid channel located within the interior;
b) a first stage compression device having an inlet in fluid communication with an outlet of the interior of the heat exchanger;
c) a first stage aftercooler having an inlet in fluid communication with the outlet of the first stage compression device, and an outlet;
d) a low pressure accumulator having an inlet in fluid communication with the outlet of the first stage aftercooler, and having a liquid outlet in fluid communication with the pre-cooled liquid passage of the heat exchanger, and a vapor outlet;
e) a second stage compression device having an inlet in fluid communication with the vapor outlet of the low pressure accumulator, and an outlet;
f) a second stage aftercooler having an inlet in fluid communication with the outlet of the second stage compression device, and an outlet;
g) a high pressure accumulator having an inlet in fluid communication with the outlet of the second stage after cooler and having a liquid outlet in fluid communication with the high pressure liquid passage of the heat exchanger and a vapor outlet in fluid communication with the high pressure vapor passage of the heat exchanger;
h) a cold vapor separator having an inlet in fluid communication with the high pressure vapor passage of the heat exchanger, a vapor outlet in fluid communication with the cold separator vapor passage of the heat exchanger, and a liquid outlet in fluid communication with the cold separator liquid passage of the heat exchanger;
i) a first expansion device having an inlet in fluid communication with the high pressure liquid passage of the heat exchanger and an outlet in fluid communication with the interior of the heat exchanger;
j) a second expansion device having an inlet in fluid communication with a cold separator liquid passage of the heat exchanger and an outlet in fluid communication with the interior of the heat exchanger;
k) a third expansion device having an inlet in fluid communication with a cold separator vapor passage of the heat exchanger and an outlet in fluid communication with the interior of the heat exchanger; and
l) a fourth expansion device having an inlet in fluid communication with the pre-cooled liquid passage of the heat exchanger and an outlet in fluid communication with the interior of the heat exchanger.
21. A method for cooling a gas with a mixed refrigerant comprising the steps of:
a) flowing the gas through the cooling passage of the heat exchanger in countercurrent, indirect heat exchange relationship with the mixed refrigerant flowing through the main refrigerant passage;
b) conditioning and separating the mixed refrigerant exiting the main refrigeration passage in the compression system to form a high boiling point refrigerant liquid stream, a high pressure vapor stream, and a mid boiling point liquid stream;
c) cooling the high pressure vapor in a heat exchanger;
d) separating the cooled high pressure vapor into a cold separator vapor stream and a cold separator liquid stream;
e) subcooling the cold separator liquid stream in a heat exchanger;
f) flashing the subcooled cold separator liquid stream to form a first cold separator mixed phase stream;
g) directing the first cold separator mixed phase stream to a main refrigeration passage;
h) cooling the cold separator vapor stream in a heat exchanger;
i) flashing the cooled cold separator vapor stream to form a second cold separator mixed phase stream;
j) directing the second cold separator mixed phase stream to a main refrigeration passage;
k) subcooling the medium boiling point liquid stream in a heat exchanger;
l) flashing the subcooled mid-boiling liquid stream to form a mid-boiling mixed phase stream;
m) directing the mid-boiling mixed phase stream to a main refrigeration passage;
n) subcooling the high boiling point refrigerant liquid stream in a heat exchanger;
o) flashing the subcooled high boiling point refrigerant liquid stream to form a high boiling point mixed phase stream; and
p) directing the high boiling mixed phase stream to the main refrigeration passage.
22. The method for cooling a gas with a mixed refrigerant of claim 21, where step g) includes separating the first cold separator mixed phase stream to form a CVS temperature vapor stream and a CVS temperature liquid stream, and directing the CVS temperature vapor and liquid streams to the primary refrigeration passage.
23. The method for cooling a gas with a mixed refrigerant according to claim 22 where step p) includes combining the high boiling mixed phase stream with the first cold separator mixed phase stream.
24. The method for cooling a gas with mixed refrigerant according to claim 21, where step m) includes separating the mid-boiling mixed phase stream to form a mid-temperature vapor stream and a mid-temperature liquid stream, and directing the mid-temperature vapor and liquid streams to the main refrigeration passage.
25. The method for cooling a gas with a mixed refrigerant according to claim 24, wherein step p) comprises combining a high boiling mixed phase stream with a mid boiling mixed phase stream.
Technical Field
The present invention relates generally to processes and systems for cooling or liquefying gases, and more particularly, to mixed refrigerant systems and methods for cooling or liquefying gases.
Background
Natural gas, which is primarily methane, and other gases are liquefied under pressure for storage and transport. The volume reduction caused by liquefaction allows the use of vessels of more practical and economical design. Liquefaction is typically achieved by cooling the gas by indirect heat exchange through one or more refrigeration cycles. Such refrigeration cycles are expensive in both equipment cost and operation due to the complexity of the equipment required and the required refrigerant performance efficiency. Accordingly, there is a need for a gas cooling and liquefaction system with increased refrigeration efficiency and reduced operating costs and reduced complexity.
The use of mixed refrigerants in the refrigeration cycle of a liquefaction system may improve efficiency because the heating profile of the refrigerant more closely matches the cooling profile of the gas. The refrigeration cycle of the liquefaction system will typically include a compression system for conditioning or handling the mixed refrigerant. A mixed refrigerant compression system typically includes one or more stages, each stage including a compressor, a cooler, and a separation and liquid accumulator (accumulator) device. The vapor leaving the compressor is cooled in a cooler and the resulting two-phase or mixed-phase stream is directed to a separation and liquid accumulator apparatus from which the vapor and liquid flow out for further processing and/or directed to a liquefaction heat exchanger.
The separated liquid and vapor phases of the mixed refrigerant from the compression system may be directed to various portions of the heat exchanger to provide more efficient cooling. Examples of such systems are provided in commonly owned U.S. patent No. 9441877 to Gushanas et al, U.S. patent application publication No. US2014/0260415 to Ducote et al, and U.S. patent application publication No. US 2016/0298898 to Ducote et al, the respective contents of which are incorporated herein by reference.
Further improvements in cooling efficiency and reduced operating costs are desired in gas cooling and liquefaction systems.
Disclosure of Invention
Aspects of the invention may be embodied separately or together in the devices and systems described and claimed below. These aspects may be used alone or in combination with other aspects of the subject matter described herein, and the description of these aspects together is not intended to exclude these aspects from being used alone or from being claimed in various combinations as set forth in the appended claims.
In one aspect, a system for cooling a gas with a mixed refrigerant includes a heat exchanger including a cooling channel having an inlet configured to receive a feed of the gas and an outlet through which a product exits the heat exchanger. The heat exchanger also includes a main refrigeration passage, a pre-cooling liquid passage, a high pressure vapor passage, a high pressure liquid passage, a cold separator vapor passage, and a cold separator liquid passage. The first stage compression device has an inlet in fluid communication with the outlet of the main refrigeration passage. The first stage after cooler has an inlet and an outlet in fluid communication with the outlet of the first stage compression device. The low pressure accumulator has an inlet in fluid communication with the outlet of the first stage aftercooler, a liquid outlet in fluid communication with the pre-cooled liquid passage of the heat exchanger, and a vapor outlet. The second stage compression device has an inlet and an outlet in fluid communication with the vapor outlet of the low pressure accumulator. The second stage aftercooler has an inlet and an outlet in fluid communication with the outlet of the second stage compression device. The high pressure accumulator has an inlet in fluid communication with the outlet of the second stage aftercooler, a liquid outlet in fluid communication with the high pressure liquid passage of the heat exchanger, and a vapor outlet in fluid communication with the high pressure vapor passage of the heat exchanger. The cold vapor separator has an inlet in fluid communication with the high pressure vapor passage of the heat exchanger, a vapor outlet in fluid communication with the cold separator vapor passage of the heat exchanger, and a liquid outlet in fluid communication with the cold separator liquid passage of the heat exchanger. The first expansion device has an inlet and an outlet in fluid communication with the high pressure liquid passage of the heat exchanger. An optional intermediate temperature separation device has an inlet in fluid communication with the outlet of the first expansion device, a vapor outlet in fluid communication with the main refrigeration passage, and a liquid outlet in fluid communication with the main refrigeration passage. The second expansion device has an inlet and an outlet in fluid communication with the cold separator liquid passage of the heat exchanger. An optional CVS temperature separation device has an inlet in fluid communication with the outlet of the second expansion device, a vapor outlet in fluid communication with the main refrigeration passage, and a liquid outlet in fluid communication with the main refrigeration passage. The third expansion device has an inlet in fluid communication with the cold separator vapor passage of the heat exchanger and an outlet in fluid communication with the main refrigeration passage. A fourth expansion device has an inlet in fluid communication with the pre-cooled liquid passage of the heat exchanger and an outlet in fluid communication with at least one of the intermediate temperature separation device, the CVS temperature separation device, and the main refrigeration passage.
In another aspect, a system for cooling a gas with a mixed refrigerant includes a heat exchanger having a cooling channel with an inlet configured to receive a feed of the gas and an outlet through which product exits the heat exchanger. The heat exchanger also includes a main refrigeration passage, a pre-cooling liquid passage, a high pressure vapor passage, a high pressure liquid passage, a cold separator vapor passage, and a cold separator liquid passage. The first stage compression device has an inlet in fluid communication with the outlet of the main refrigeration passage. The first stage after cooler has an inlet and an outlet in fluid communication with the outlet of the first stage compression device. The low pressure accumulator has an inlet in fluid communication with the outlet of the first stage aftercooler, a liquid outlet in fluid communication with the pre-cooled liquid passage of the heat exchanger, and a vapor outlet. The second stage compression device has an inlet and an outlet in fluid communication with the vapor outlet of the low pressure accumulator. The second stage aftercooler has an inlet and an outlet in fluid communication with the outlet of the second stage compression device. The high pressure accumulator has an inlet in fluid communication with the outlet of the second stage aftercooler, and has a liquid outlet in fluid communication with the high pressure liquid passage of the heat exchanger and a vapor outlet in fluid communication with the high pressure vapor passage of the heat exchanger. The cold vapor separator has an inlet in fluid communication with the high pressure vapor passage of the heat exchanger, a vapor outlet in fluid communication with the cold separator vapor passage of the heat exchanger, and a liquid outlet in fluid communication with the cold separator liquid passage of the heat exchanger. The first expansion device has an inlet in fluid communication with the high pressure liquid passage of the heat exchanger and an outlet in fluid communication with the main refrigeration passage. The second expansion device has an inlet in fluid communication with the cold separator liquid passage of the heat exchanger and an outlet in fluid communication with the main refrigeration passage. The third expansion device has an inlet in fluid communication with the cold separator vapor passage of the heat exchanger and an outlet in fluid communication with the main refrigeration passage. A fourth expansion device has an inlet in fluid communication with the pre-cooled liquid passage of the heat exchanger and an outlet in fluid communication with the main refrigeration passage.
In another aspect, a system for cooling a gas with a mixed refrigerant has a heat exchanger including a cooling channel having an inlet configured to receive a feed of the gas and an outlet through which a product exits the heat exchanger. The heat exchanger also includes a main refrigeration passage, a high pressure vapor passage, a high pressure liquid passage, a cold separator vapor passage, and a cold separator liquid passage. The compression device has an inlet in fluid communication with the outlet of the main refrigeration passage. The aftercooler has an inlet and an outlet in fluid communication with the outlet of the compression device. The accumulator has an inlet in fluid communication with the outlet of the aftercooler, a liquid outlet in fluid communication with the high pressure liquid passage of the heat exchanger, and a vapor outlet in fluid communication with the high pressure vapor passage of the heat exchanger. The cold vapor separator has an inlet in fluid communication with the high pressure vapor passage of the heat exchanger, a vapor outlet in fluid communication with the cold separator vapor passage of the heat exchanger, and a liquid outlet in fluid communication with the cold separator liquid passage of the heat exchanger. The first expansion device has an inlet and an outlet in fluid communication with the high pressure liquid passage of the heat exchanger. The intermediate temperature separation device has an inlet in fluid communication with the outlet of the first expansion device, a vapor outlet in fluid communication with the main refrigeration passage, and a liquid outlet in fluid communication with the main refrigeration passage. The second expansion device has an inlet in fluid communication with the cold separator liquid passage of the heat exchanger and an outlet in fluid communication with the main refrigeration passage. The third expansion device has an inlet in fluid communication with the cold separator vapor passage of the heat exchanger and an outlet in fluid communication with the main refrigeration passage.
In another aspect, a system for cooling a gas with a mixed refrigerant has a heat exchanger including a cooling channel having an inlet configured to receive a feed of the gas and an outlet through which a product exits the heat exchanger. The heat exchanger also includes a main refrigeration passage, a high pressure vapor passage, a high pressure liquid passage, a cold separator vapor passage, and a cold separator liquid passage. The compression device has an inlet in fluid communication with the outlet of the main refrigeration passage. The aftercooler has an inlet and an outlet in fluid communication with the outlet of the compression device. The accumulator has an inlet in fluid communication with the outlet of the aftercooler, a liquid outlet in fluid communication with the high pressure liquid passage of the heat exchanger, and a vapor outlet in fluid communication with the high pressure vapor passage of the heat exchanger. The cold vapor separator has an inlet in fluid communication with the high pressure vapor passage of the heat exchanger, a vapor outlet in fluid communication with the cold separator vapor passage of the heat exchanger, and a liquid outlet in fluid communication with the cold separator liquid passage of the heat exchanger. The first expansion device has an inlet in fluid communication with the high pressure liquid passage of the heat exchanger and an outlet in fluid communication with the main refrigeration passage. The second expansion device has an inlet and an outlet in fluid communication with the cold separator liquid passage of the heat exchanger. The CVS temperature separation device has an inlet in fluid communication with the outlet of the second expansion device, a vapor outlet in fluid communication with the main refrigeration passage, and a liquid outlet in fluid communication with the main refrigeration passage. The third expansion device has an inlet in fluid communication with the cold separator vapor passage of the heat exchanger and an outlet in fluid communication with the main refrigeration passage.
In yet another aspect, a system for cooling a gas with a mixed refrigerant has a heat exchanger including a shell defining an interior, a cooling channel located within the interior, and the cooling channel having an inlet configured to receive a feed of the gas and an outlet through which the product exits the heat exchanger. The heat exchanger also includes a pre-cooling liquid passage, a high pressure vapor passage, a high pressure liquid passage, a cold separator vapor passage, and a cold separator liquid passage within the interior. The first stage compression device has an inlet in fluid communication with an outlet in the interior of the heat exchanger. The first stage after cooler has an inlet and an outlet in fluid communication with the outlet of the first stage compression device. The low pressure accumulator has an inlet in fluid communication with the outlet of the first stage aftercooler, a liquid outlet in fluid communication with the pre-cooled liquid passage of the heat exchanger, and a vapor outlet. The second stage compression device has an inlet and an outlet in fluid communication with the vapor outlet of the low pressure accumulator. The second stage aftercooler has an inlet and an outlet in fluid communication with the outlet of the second stage compression device. The high pressure accumulator has an inlet in fluid communication with the outlet of the second stage aftercooler, a liquid outlet in fluid communication with the high pressure liquid passage of the heat exchanger, and a vapor outlet in fluid communication with the high pressure vapor passage of the heat exchanger. The cold vapor separator has an inlet in fluid communication with the high pressure vapor passage of the heat exchanger, a vapor outlet in fluid communication with the cold separator vapor passage of the heat exchanger, and a liquid outlet in fluid communication with the cold separator liquid passage of the heat exchanger. The first expansion device has an inlet in fluid communication with the high pressure liquid passage of the heat exchanger and an outlet in fluid communication with the interior of the heat exchanger. The second expansion device has an inlet in fluid communication with the cold separator liquid passage of the heat exchanger and an outlet in fluid communication with the interior of the heat exchanger. The third expansion device has an inlet in fluid communication with the cold separator vapor passage of the heat exchanger and an outlet in fluid communication with the interior of the heat exchanger. The fourth expansion device has an inlet in fluid communication with the pre-cooled liquid passage of the heat exchanger and an outlet in fluid communication with the interior of the heat exchanger.
In another aspect, a method for cooling a gas with a mixed refrigerant includes the steps of: flowing the gas through the cooling passage of the heat exchanger in countercurrent, indirect heat exchange relationship with the mixed refrigerant flowing through the main refrigerant passage; conditioning and separating the mixed refrigerant exiting the main refrigeration passage in the compression system to form a high boiling point refrigerant liquid stream, a high pressure vapor stream, and a mid boiling point liquid stream; cooling the high pressure vapor in a heat exchanger; separating the cooled high pressure vapor into a cold separator vapor stream and a cold separator liquid stream; subcooling a cold separator liquid stream in a heat exchanger; flashing the subcooled cold separator liquid stream to form a first cold separator mixed phase stream; directing the first cold separator mixed phase stream to a main refrigeration passage; cooling the cold separator vapor stream in a heat exchanger; flashing the cooled cold separator vapor stream to form a second cold separator mixed phase stream; directing the second cold separator mixed phase stream to a main refrigeration passage; subcooling a medium boiling point liquid stream in a heat exchanger; flashing the subcooled mid-boiling liquid stream to form a mid-boiling mixed phase stream; directing the mid-boiling mixed phase stream to a main refrigeration passage; subcooling a high boiling point refrigerant liquid stream in a heat exchanger; flash evaporating the subcooled high boiling point refrigerant liquid stream to form a high boiling point mixed phase stream; and directing the high-boiling mixed phase stream to the main refrigeration passage.
Drawings
FIG. 1 is a process flow diagram and schematic diagram showing a first embodiment of the process and system of the present invention;
FIG. 2 is a process flow diagram and schematic diagram illustrating a second embodiment of the process and system of the present invention;
FIG. 3 is a process flow diagram and schematic diagram showing a third embodiment of the process and system of the present invention;
FIG. 4 is a process flow diagram and schematic diagram showing a fourth embodiment of the process and system of the present invention;
FIG. 5 is a process flow diagram and schematic showing a fifth embodiment of the process and system of the present invention;
FIG. 6 is a process flow diagram and schematic illustrating a sixth embodiment of the process and system of the present invention.
Detailed Description
A first embodiment of a mixed refrigerant liquefaction system is generally indicated at 10 in fig. 1. The system includes a compression system, generally indicated at 12, and a heat exchanger system, generally indicated at 14. The removal of heat is accomplished in the
It should be noted here that channels and flows are sometimes referred to by the same element numbers listed in the figures. Further, as used herein, and as known in the art, a heat exchanger is a device or a region in a device where indirect heat exchange occurs between two or more streams at different temperatures or between a stream and the environment. As used herein, the term "communicate," variants thereof, and the like, generally refers to fluid communication, unless otherwise indicated. Furthermore, although the two fluids in communication may exchange heat upon mixing, such exchange will not be considered the same as in a heat exchanger, although such exchange may occur in a heat exchanger. As used herein, the term "reduced pressure" (or variants thereof) does not relate to a phase change, whereas the term "flash" (or variants thereof) relates to a phase change, even including partial phase changes. As used herein, the terms "high," "medium," "warm," and the like are relative to a comparable stream as is customary in the art.
The heat exchanger system includes a multiple stream heat exchanger, generally indicated at 16, having a
The system of fig. 1 including
Referring to the
From the vapor outlet of the low pressure accumulator 44, the
Although the first and second compressor stages are shown as part of a single compressor, separate compressors may alternatively be used. In addition, the system is not limited to only two compression and cooling stages, more or fewer may be used.
Turning to the
The cold
A level detector or sensor, indicated at 117 in fig. 1, determines the level of liquid in the
From the
The combined refrigerant streams from
In the embodiment of the system shown in fig. 1, instead of mixing the liquid from the
The configuration shown in fig. 1 may be modified to reduce the cost and complexity of various sized liquid natural gas plants. For example, in an alternative embodiment shown in FIG. 2, the
The remainder of the system of fig. 2 and corresponding components are the same as in the case of the systems of fig. 3-6, with the exception of the following description, and operate in the same manner, as described above with respect to the system of fig. 1.
In another embodiment shown in FIG. 3, the
As shown in fig. 4, in contrast to the system of fig. 1-3, an alternative embodiment of the system may be configured to operate without using low pressure refrigerant from the low pressure accumulator 444.
In another alternative configuration shown in fig. 5, the flow of liquid refrigerant from the low pressure accumulator is sent to intermediate temperature riser 526 or CVS temperature riser 514 instead of entering the heat exchanger separately. More specifically, referring to fig. 5, liquid stream 548 exiting low-pressure accumulator 544 is warm and a substantial portion of the mixed refrigerant, enters pre-cooling liquid passage 552 of heat exchanger 516 and is sub-cooled. The resulting subcooled high boiling point stream 554 exits the heat exchanger and is depressurized or flashed through expansion device 556. The resulting refrigerant flow 558 is directed to intermediate temperature riser 526. Alternatively or additionally, as shown in phantom at 560, the flow of refrigerant exiting expansion device 556 may be directed to CVS temperature riser 514. As another alternative, as shown by the dashed line at 561 in FIG. 5, a portion or all of the refrigerant flow 558 may be directed to the main refrigerant passage 506.
The system and process of fig. 5 reduces the number of injection points into the main refrigerant path 506 of the heat exchanger 516. Considering that each injection point into the main cooling path causes a pressure drop in the path, reducing the number of injection points reduces the power consumption of the system, thereby improving the operation efficiency. In addition, the manufacture of the heat exchanger is simplified, which reduces the equipment costs.
In another alternative configuration shown in fig. 6, a core-to-kettle or shell-and-
In the embodiment of fig. 6,
The
The
The cold
A medium boiling point refrigerant
Each refrigerant stream directed to the kettle or shell of
While the preferred embodiments of the invention have been illustrated and described, it will be apparent to those skilled in the art that changes and modifications may be made therein without departing from the spirit of the invention, the scope of which is defined in the appended claims.
- 上一篇:一种医用注射器针头装配设备
- 下一篇:天然气凝液回收的过程集成