KR101628841B1 - Method and apparatus for liquefying natural gas - Google Patents
Method and apparatus for liquefying natural gas Download PDFInfo
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- KR101628841B1 KR101628841B1 KR1020100065759A KR20100065759A KR101628841B1 KR 101628841 B1 KR101628841 B1 KR 101628841B1 KR 1020100065759 A KR1020100065759 A KR 1020100065759A KR 20100065759 A KR20100065759 A KR 20100065759A KR 101628841 B1 KR101628841 B1 KR 101628841B1
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Abstract
A large heat exchanger used for liquefying natural gas is separated into a cold core and a warm core in a single cold box to be mounted on a floating structure used floating in the sea, To a natural gas liquefaction method and apparatus.
According to the present invention, there is provided a natural gas liquefying apparatus for liquefying natural gas by heat exchange with a refrigerant in a heat exchanging means, wherein the heat exchanging means comprises a low temperature heat exchanger for cooling the natural gas extracted from the gas chill to a low temperature, And a cryogenic heat exchanger for further cooling and liquefying the cooled natural gas, wherein the refrigerant heated by the natural gas in the cryogenic temperature heat exchanger is precooled by supplying the natural gas before being supplied to the cryogenic heat exchanger, And the refrigerant supplied from the cryogenic heat exchanger to the low temperature heat exchanger is protected from thermal shock by passing through the heat shock preventing means.
Description
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for liquefying natural gas, in which a large-sized heat exchanger used for liquefying natural gas is separated into a plurality of heat exchangers and is installed and used on a float- To a method and apparatus for liquefying natural gas. More specifically, when a Brazed Aluminum Heat Exchanger (BAHX) is used as a large-scale cryogenic heat exchanger used for liquefying natural gas, a cold core and a warm core are separately installed in a cold box, And separating one large-sized heat exchanger into a low-temperature heat exchanger and a cryogenic heat exchanger when SWHE (Spiral Wound Heat Exchanger) is used, thereby making it suitable for use in the sea.
Natural gas is transported in a gaseous state through land or sea gas pipelines, or is transported to a remote location where it is stored in an LNG carrier in the form of liquefied natural gas (LNG). Liquefied natural gas is obtained by cooling the natural gas at a cryogenic temperature, and its volume is reduced to approximately 1/600 of that of the natural gas, making it very suitable for long distance transportation through the sea.
A conventionally used method of liquefying natural gas is by passing natural gas through a heat exchanger and cooling it. U.S. Patent Nos. 3,735,600 and 3,433,026 disclose a liquefaction method in which natural gas is supplied to a heat exchanger for liquefaction.
In this specification, natural gas means a mixture containing methane as the main component but containing other hydrocarbon components or nitrogen, and also includes any type (gas phase, liquid phase, or mixed phase of gas phase and liquid phase) .
In order to store and transport natural gas in a liquid state, the natural gas must be cooled to about -151 캜 to -163 캜, where the LNG has a pressure of about atmospheric pressure. In the prior art, methods such as a cascade process, a mixed refrigerant process, a refrigerant gas expander process and the like have been used for the cooling of natural gas in a liquefaction facility on the land.
Floating structures such as LNG FPSO (Floating, Production, Storage and Offloading), which can directly produce and store natural gas directly from raw natural gas extracted from gas fired offshore, have been proposed recently, There has been a demand for a liquefaction apparatus for natural gas.
The method of liquefaction of natural gas on land can not be applied to floating structures in the sea as it is, and needs to be improved to suit the marine environment. In the case of LNG FPSO, small- and medium-scale liquefaction facilities are highly feasible, and gas refrigerant expansion processes and mixed refrigerant processes are attracting attention as a liquefaction process suitable for this.
However, heat exchangers such as BAHX (Brazed Aluminum Heat Exchanger) or SWHE (Spiral Wound Heat Exchanger) are used for such a liquefaction facility. BAHX has a large heat transfer area per unit volume and relatively low cost. However, There is a risk of damage due to thermal shock due to a sudden change, and the SWHE is expensive, and has a high height (for example, about 50 m) at a high cost.
In order to solve these problems, the present invention is characterized in that, instead of installing a single large heat exchanger in a floating structure for liquefying natural gas, a plurality of relatively small heat exchangers are installed and cold heat is transmitted to the plurality of heat exchangers The present invention is to provide a natural gas liquefaction method and apparatus capable of minimizing the influence due to fluctuations in the sea and performing the liquefaction process stably and efficiently.
According to an aspect of the present invention, there is provided a natural gas liquefying apparatus for liquefying natural gas by heat exchange with a refrigerant in a heat exchanging means, wherein the heat exchanging means includes a low temperature heat exchanger for cooling the natural gas extracted from the gas chill to a low temperature And a cryogenic heat exchanger for further cooling and liquefying the natural gas cooled in the low temperature heat exchanger. In the cryogenic heat exchanger, the refrigerant heated by the natural gas is supplied to the low temperature heat exchanger, And the refrigerant supplied from the cryogenic heat exchanger to the low temperature heat exchanger is protected from thermal shock by passing through the heat shock preventing means.
When the low temperature heat exchanger and the cryogenic heat exchanger are PFHE (Plate Fin Heat Exchanger) type heat exchangers, they can be installed in one cold box.
The heat shock prevention means is preferably a gas-liquid separator for separating the refrigerant supplied from the cryogenic heat exchanger into the low-temperature heat exchanger into a gaseous refrigerant and a liquid refrigerant.
The refrigerant circulates along a refrigerant circuit consisting of a single closed circuit that sequentially passes through the low-temperature heat exchanger and the cryogenic heat exchanger, at least partially liquefies natural gas, and then returns via the low-temperature heat exchanger.
The natural gas liquefier further includes a cold separator for separating the natural gas cooled at a low temperature in the low temperature heat exchanger into a natural gas in a gaseous state and a natural gas in a liquid state and supplying the gaseous natural gas to the cryogenic heat exchanger .
It is preferable that the natural gas liquefier includes means for separating the liquid natural gas separated by the cold separator by the component.
Preferably, a plurality of the low-temperature heat exchangers are provided, and the gaseous refrigerant separated through the gas-liquid separator and the liquid-state refrigerant are supplied to a plurality of the low-temperature heat exchangers through separate supply lines.
Preferably, the refrigerant circuit includes at least one compressor including a refrigerant compressor for compressing a refrigerant that cools natural gas through heat exchange with natural gas, and a refrigerant condenser for condensing the compressed refrigerant.
The refrigerant supplied to the low temperature heat exchanger in the compression unit is separated and supplied to the gaseous refrigerant and the liquid refrigerant through the discharge separator.
The natural gas liquefaction apparatus may further include a refrigerant compressor for compressing the refrigerant and a refrigerant condenser for condensing the compressed refrigerant, wherein the refrigerant compressor is a multi-stage compressor.
The refrigerant supplied to the low-temperature heat exchanger is supplied to the low-temperature heat exchanger through a first refrigerant supply line (not shown) for supplying refrigerant in a liquid state separated by the intermediate separator among the refrigerant partially cooled by the intermediate cooler between the multi- And a second separator for separating the refrigerant separated from the refrigerant in the gaseous state by the refrigerant compressor and partially condensing the refrigerant by the refrigerant condenser and for supplying the liquid refrigerant separated from the discharge separator to the low temperature heat exchanger, A coolant supply line and a third coolant supply line for supplying the gaseous coolant separated from the discharge separator to the low temperature heat exchanger.
The refrigerant supplied to the low temperature heat exchanger through the third refrigerant supply line is cooled and partially condensed by the refrigerant returning from the cryogenic temperature heat exchanger and is separated into a gaseous refrigerant and a liquid refrigerant by the first refrigerant separator Respectively, and then the natural gas is cooled in the cryogenic heat exchanger.
Preferably, the refrigerant supplied to the low-temperature heat exchanger through the first and second refrigerant supply lines is expanded and then supplied to the low-temperature heat exchanger to cool the natural gas.
The expanded refrigerant is mixed with the refrigerant supplied to the low temperature heat exchanger in the cryogenic heat exchanger and the heat shock preventing means to return to the low temperature heat exchanger.
The low temperature heat exchanger and the ultra low temperature heat exchanger may be a plate heat exchanger (PFHE) type or a spiral wound heat exchanger (SWHE) type heat exchanger.
According to another aspect of the present invention, there is provided a natural gas liquefaction apparatus for liquefying natural gas by exchanging natural gas with a refrigerant on a float-type floating structure used at sea, the natural gas liquefying apparatus being disposed on an upper deck of the floating structure, A low temperature heat exchanger for cooling the gas to a low temperature; A cryogenic heat exchanger disposed on an upper deck of the floating structure for further cooling and liquefying the natural gas cooled in the low temperature heat exchanger; Temperature shock absorber disposed between the cryogenic heat exchanger and the low-temperature heat exchanger to prevent the refrigerant discharged from the ultra-low temperature heat exchanger from being supplied directly to the low-temperature heat exchanger, thereby protecting the low-temperature heat exchanger from thermal shock; The natural gas liquefaction apparatus comprising:
According to another aspect of the present invention, there is provided a floating structure used floating in a sea, comprising: a low temperature heat exchanger disposed on an upper deck of the floating structure for cooling natural gas extracted from a gas chill to a low temperature; A cryogenic heat exchanger disposed on an upper deck of the floating structure for further cooling and liquefying the natural gas cooled in the low temperature heat exchanger; Temperature shock absorber disposed between the cryogenic heat exchanger and the low-temperature heat exchanger to prevent the refrigerant discharged from the ultra-low temperature heat exchanger from being supplied directly to the low-temperature heat exchanger, thereby protecting the low-temperature heat exchanger from thermal shock; And a natural gas liquefaction apparatus including the natural gas liquefaction apparatus.
The floating structure is preferably LNG FPSO.
According to another aspect of the present invention, there is provided a natural gas liquefaction method for liquefying natural gas by heat exchange with a coolant in a heat exchange unit, comprising: cooling a natural gas extracted from a gas chill to a low temperature in a low temperature heat exchanger; The natural gas is further cooled in the cryogenic heat exchanger to at least partially liquefy the refrigerant heated by the natural gas in the cryogenic heat exchanger is further heated in the thermal shock prevention means and supplied to the low temperature heat exchanger to protect the low temperature heat exchanger from thermal shock The natural gas liquefaction method comprising the steps of:
According to the present invention as described above, instead of installing one large heat exchanger in a floating structure for liquefying natural gas, a plurality of relatively small heat exchangers are provided, and in order to transfer cold heat to the plurality of heat exchangers, A natural gas liquefaction method and apparatus in which a refrigerant circuit for circulating a natural gas is constituted by a single circuit can be provided.
Accordingly, according to the present invention, when BAHX is used as a cryogenic heat exchanger in a floating structure for liquefying natural gas, a cold core and a warm core are separately installed in a cold box, It is possible to reduce the amount of heat that has reached 200 ° C to about half, thereby mitigating the impact due to the expected thermal stress in an abnormal situation. When using SWHX, one large heat exchanger is separated into a low temperature heat exchanger and a cryogenic heat exchanger, Thereby minimizing the risk of performance deterioration of the heat exchanger.
Further, according to the present invention, by providing the separator between the plurality of heat exchangers, it is possible to reduce the thermal shock that can be caused by the cold refrigerant discharged from the heat exchanger of a lower temperature among the plurality of heat exchangers, do.
FIG. 1 is a conceptual view of a floating structure in which a natural gas liquefaction apparatus according to the present invention is installed,
2 is a conceptual view for explaining a natural gas liquefaction apparatus according to a first embodiment of the present invention, and Fig.
3 is a conceptual diagram for explaining a natural gas liquefaction apparatus according to a second embodiment of the present invention.
Hereinafter, a method and apparatus for liquefying natural gas according to a preferred embodiment of the present invention will be described in detail with reference to the drawings.
The natural gas liquefaction apparatus according to the present invention can be installed in a marine structure such as LNG plant, LNG carrier, and LNG FPSO (Floating, Production, Storage and Offloading) installed on land or in the sea. LNG FPSO is a floating marine structure that is used to liquefy natural gas produced directly from the sea and store it in the LNG storage tank and to transfer the LNG stored in the LNG storage tank to the LNG transport if necessary.
As shown in FIG. 1, the natural gas liquefaction apparatus 1 according to the present invention for liquefying natural gas extracted from a gas chest provided in a floating structure 2, is extracted from a gas chest, A low-
The low-
According to the present invention, as the refrigerant circulated in the refrigerant circuit (5), a mixed refrigerant in which components such as methane, ethanol, propane, butane, and nitrogen are mixed at a certain ratio may be used. The mixing ratio of each component can be determined according to the process conditions.
As described above, according to the natural gas liquefier 1 of the present invention, by using a plurality of heat exchangers, that is, the low
(First Embodiment)
Next, the natural gas liquefaction method and apparatus according to the first embodiment of the present invention will be described in more detail with reference to Fig.
As described above with reference to Fig. 1, the natural gas liquefaction apparatus of the present invention comprises: a low-
The liquefaction process of natural gas can be carried out as follows.
The natural gas that has been subjected to a pretreatment process such as the removal of impurities after being extracted from the gas well is supplied to the low
The primarily cooled natural gas is supplied to the
According to a modified embodiment of the present invention, the natural gas delivered from the low-
Natural gas contains hydrocarbon components such as methane, ethane, propane, and butane. Methane, ethane, etc., which have relatively high liquefaction point and relatively low carbon number, are relatively low in liquid hydrocarbon such as butane and propane. Accordingly, the natural gas of the gas phase classified by the
The liquid natural gas classified from the
The circulation process of the refrigerant can be performed as follows.
The refrigerant compressed in the
According to the present invention, one or more compression units provided with a
Since the configuration of the
When the refrigerant compressor (21) is driven, the refrigerant contained in the suction drum (23) provided on the upstream side of the refrigerant compressor (21) is supplied to the refrigerant compressor (21) and compressed. Since the refrigerant compressor is composed of multiple stages, the refrigerant compressed at the intermediate pressure in the primary compression stage is cooled in the intermediate refrigerator (24) and then compressed to the high pressure in the secondary compression stage.
In the
On the other hand, the refrigerant of the gaseous component compressed at the high pressure in the secondary compression step is merged with the refrigerant supplied through the first refrigerant supply line L21, and then the temperature is lowered in the refrigerant condenser 26 (also referred to as aftercooler) And the partially condensed refrigerant is separated into a gas phase and a liquid phase again in a
Here, in each compression zone, the respective refrigerant distributions separated in the same step are joined together before being supplied to the low
The refrigerant fraction supplied to the low
On the other hand, the refrigerant fraction supplied to the low-
The liquid-phase refrigerant supplied to the cryogenic
The gaseous refrigerant supplied to the cryogenic
In this cryogenic heat exchanger (4), heat is taken from the natural gas and the heated refrigerant is partially vaporized, and the gas phase and the liquid phase coexist. The liquid refrigerant is discharged from the lower end of the
As described above, the refrigerant returning from the cryogenic heat exchanger (4) to the refrigerant compressor (21) is mixed with the refrigerant expanded after passing through the low temperature heat exchanger (3) and then supplied to the low temperature heat exchanger (3).
Here, when a plurality of low-
Since the refrigerant supplied from the
When the refrigerant in a vapor-liquid mixed state is directly supplied to a plurality of low-temperature heat exchangers, a relatively large amount of gaseous refrigerant is supplied to a specific low-temperature heat exchanger, and a relatively large amount of liquid refrigerant is supplied to another low- There is a possibility that operating conditions may be different for each heat exchanger.
If a plurality of low-
The returning refrigerant can be mixed with the gas component and the liquid component immediately before being supplied to the low temperature heat exchanger (3) and can pass through the low temperature heat exchanger (3). The return refrigerant heated while passing through the low temperature heat exchanger (3) while cooling the natural gas supplied to the cryogenic temperature heat exchanger (4) and the supply refrigerant (that is, the refrigerant moving from the refrigerant compressor to the cryogenic heat exchanger) (L35) to the suction drum (23).
On the other hand, according to a modification of the first embodiment of the present invention, the refrigerant partially condensed in the
At this time, the refrigerant supplied to the low-
Accordingly, in the modified example of the first embodiment, compared with the liquefaction apparatus according to the first embodiment, a separate refrigerant supply line for supplying the liquid component separated from the
According to the first embodiment and its modifications of the present invention, a PFHE (Plate Fin Heat Exchanger) type heat exchanger can be used as the low temperature heat exchanger for precooling natural gas, and as a cryogenic heat exchanger for at least partially liquefying natural gas A SWHE (Spiral Wound Heat Exchanger) type heat exchanger may be used. However, it can be modified to use a PFHE type heat exchanger as the cryogenic heat exchanger.
Further, according to the first embodiment and its modifications of the present invention, a process of extracting NGL having a large amount of heavy hydrocarbon components from natural gas cooled in the low
According to a modification of the first embodiment of the present invention, the refrigerant compressed in the compressor is separated into three (that is, the liquid refrigerant separated in the
According to the natural gas liquefaction method and apparatus of the first embodiment and its modifications, a single mixed refrigerant cycle (SMR) constituting a single closed loop can be obtained by using a mixed refrigerant composed of nitrogen and a hydrocarbon- It is possible to realize an appropriate liquefaction process for a floating structure such as an LNG FPSO having a limited space by combining the NGL (Natural Gas Liquid) processing process with the environment characteristic.
(Second Embodiment)
Next, the natural gas liquefaction method and apparatus according to the second embodiment of the present invention will be described in more detail with reference to Fig. In describing the natural gas liquefier according to the second embodiment, the same or similar components as those of the natural gas liquefier according to the first embodiment are given the same reference numerals.
The natural gas liquefier according to the second embodiment also includes a warm core, that is, a low-
In FIG. 2 showing the first embodiment described above, a PFHE (Plate Fin Heat Exchanger) type heat exchanger is used as a low temperature heat exchanger for precooling natural gas and a cryogenic heat exchanger for at least partially liquefying natural gas is called a Spiral Wound Heat Exchanger ) Type heat exchanger is used. However, in FIG. 3 showing the second embodiment, it is exemplified that a PFHE (Plate Fin Heat Exchanger) type heat exchanger is used in both the low temperature heat exchanger and the ultra low temperature heat exchanger.
In addition, the low
The liquefaction process of natural gas can be carried out as follows.
The natural gas that has been subjected to a pretreatment process such as the removal of impurities after being extracted from the gas well is supplied to the low
The primarily cooled natural gas is supplied to the
According to a modified embodiment of the present invention, the natural gas delivered from the low-
Natural gas contains hydrocarbon components such as methane, ethane, propane, and butane. Methane, ethane, etc., which have relatively high liquefaction point and relatively low carbon number, are relatively low in liquid hydrocarbon such as butane and propane. Accordingly, the natural gas of the gas phase classified by the
The liquid natural gas classified from the
The circulation process of the refrigerant can be performed as follows.
The refrigerant compressed in the
According to the present invention, one or more compression units provided with the
As the refrigerant compressor provided in the
When the
In the
On the other hand, the refrigerant of the gaseous component compressed at the high pressure in the second
The refrigerant fraction supplied to the low
On the other hand, the refrigerant fraction supplied to the low-
The liquid-phase refrigerant supplied to the cryogenic
The gaseous refrigerant supplied to the
When the refrigerant that has passed through the
The refrigerant supplied back into the intermediate portion of the cryogenic
As described above, the refrigerant returning from the
Here, in the case where a plurality of low-
Since the refrigerant supplied from the
When the refrigerant in a vapor-liquid mixed state is directly supplied to a plurality of low-temperature heat exchangers, a relatively large amount of gaseous refrigerant is supplied to a specific low-temperature heat exchanger, and a relatively large amount of liquid refrigerant is supplied to another low- There is a possibility that operating conditions may be different for each heat exchanger.
If a plurality of low-
The returning refrigerant can be mixed with the gas component and the liquid component immediately before being supplied to the low temperature heat exchanger (3) and can pass through the low temperature heat exchanger (3). The return refrigerant heated while passing through the low temperature heat exchanger (3) while cooling the natural gas supplied to the cryogenic temperature heat exchanger (4) and the supply refrigerant (that is, the refrigerant moving from the refrigerant compressor to the cryogenic heat exchanger) (L35) to the suction drum (23).
On the other hand, according to a modification of the second embodiment of the present invention, the refrigerant partially condensed in the
At this time, the refrigerant supplied to the low-
Accordingly, in the modified example of the second embodiment, compared with the liquefaction apparatus according to the second embodiment, a separate refrigerant supply line for supplying the liquid component separated from the
According to another modification of the second embodiment of the present invention, it is possible to provide a plurality of compression sections as compared with the natural gas liquefier according to the second embodiment, and it is also possible to use the third and fourth refrigerant separators . ≪ / RTI >
The
In another modification of the second embodiment, the third
In the case where there are a plurality of cryogenic heat exchangers, a refrigerant line from a plurality of cryogenic heat exchangers is supplied to each of the cryogenic heat exchangers so that a refrigerant line and an expansion valve are constituted to form a line returning to the same plurality of cryogenic heat exchangers, And it is possible to prevent the operating conditions of the respective ultra-low temperature heat exchangers from being different from each other.
As described above, according to the second embodiment of the present invention and its modifications, a low-temperature heat exchanger for precooling natural gas and a cryogenic heat exchanger for at least partially liquefying natural gas, a heat exchanger of a Plate Fin Heat Exchanger (PFHE) Can be used. However, it goes without saying that a heat exchanger other than the PFHE type may be used.
Further, according to the second embodiment and its modifications of the present invention, a process of extracting NGL having a large amount of heavy hydrocarbon components from the natural gas cooled in the low
According to the method and apparatus for liquefying natural gas of the second embodiment and its modifications, a single mixed refrigerant cycle (SMR) constituting a single closed loop is formed by using a mixed refrigerant composed of nitrogen and hydrocarbon series It is possible to realize an appropriate liquefaction process for a floating structure such as an LNG FPSO having a limited space by combining NGL (Natural Gas Liquid) processing process.
As described above, the natural gas liquefaction method and apparatus according to the present invention have been described with reference to the drawings. However, the present invention is not limited to the above-described embodiments and drawings, It will be understood by those skilled in the art that various changes and modifications may be made.
1: Natural gas liquefier 2: Floating structure 3: Low temperature heat exchanger 4: Cryogenic heat exchanger 5: Refrigerant circuit 9: Cold box 11: Cold separator 12: Pressure reducing valve 13: LNG receiver A refrigerant compressor for compressing the refrigerant in the first refrigerant compressor and a refrigerant compressor for compressing the refrigerant in the first refrigerant compressor; Wherein the first refrigerant separator comprises a first refrigerant separator and a second refrigerant separator which is connected to the first refrigerant separator and the second refrigerant separator. L22: second refrigerant supply line, L23: third refrigerant supply line, L24: fourth gas supply line, L13: liquid natural gas supply line, L14: second natural gas supply line, L21: first refrigerant supply line, L34 is the third refrigerant return line, L34 is the fourth refrigerant returning line, L34 is the fourth refrigerant returning line, Every return line, L35: the fifth coolant return line
Claims (20)
Wherein the heat exchanging means includes a low temperature heat exchanger for cooling the natural gas extracted from the gas well to a low temperature and a cryogenic heat exchanger for further cooling and liquefying the natural gas cooled in the low temperature heat exchanger,
The refrigerant heated by the natural gas in the cryogenic heat exchanger is precooled by the natural gas before being supplied to the cryogenic heat exchanger. The refrigerant supplied from the cryogenic heat exchanger to the low-temperature heat exchanger is passed through the heat shock- Thereby protecting the low-temperature heat exchanger from thermal shock,
Further comprising a cold separator for separating the natural gas cooled at a low temperature in the low temperature heat exchanger into a natural gas in a gaseous state and a natural gas in a liquid state and supplying the gaseous natural gas to the ultra low temperature heat exchanger, Liquefaction device.
Wherein the low temperature heat exchanger and the ultra low temperature heat exchanger are installed in one cold box.
Wherein the heat shock prevention means is a gas-liquid separator for separating the refrigerant supplied from the cryogenic temperature heat exchanger into the low temperature heat exchanger into a gaseous refrigerant and a liquid refrigerant.
Wherein the refrigerant is circulated through a refrigerant circuit consisting of a single closed circuit that sequentially passes through the low temperature heat exchanger and the cryogenic temperature heat exchanger and at least partially liquefies natural gas and then returns via the low temperature heat exchanger Natural gas liquefaction equipment.
And means for separating the liquid natural gas separated by the cold separator by the component.
Wherein a plurality of the low temperature heat exchangers are installed and the gaseous refrigerant separated through the gas-liquid separator and the liquid refrigerant are supplied to the plurality of low temperature heat exchangers through separate supply lines.
Wherein the refrigerant circuit comprises at least one compression unit including a refrigerant compressor for compressing a refrigerant for cooling natural gas through heat exchange with natural gas and a refrigerant condenser for condensing the compressed refrigerant, Device.
Wherein the refrigerant supplied to the low-temperature heat exchanger in the compression unit is separately supplied to the gaseous refrigerant and the liquid refrigerant through the discharge separator.
A refrigerant compressor for compressing the refrigerant, and a refrigerant condenser for condensing the compressed refrigerant, wherein the refrigerant compressor is a multi-stage compressor.
The refrigerant supplied to the low-temperature heat exchanger is supplied to the low-temperature heat exchanger through a first refrigerant supply line (not shown) for supplying refrigerant in a liquid state separated by the intermediate separator among the refrigerant partially cooled by the intermediate cooler between the multi- And a second separator for separating the refrigerant separated from the refrigerant in the gaseous state by the refrigerant compressor and partially condensing the refrigerant by the refrigerant condenser and for supplying the liquid refrigerant separated from the discharge separator to the low temperature heat exchanger, A refrigerant supply line, and a third refrigerant supply line for supplying gaseous refrigerant separated from the discharge separator to the low temperature heat exchanger.
The refrigerant supplied to the low temperature heat exchanger through the third refrigerant supply line is cooled and partially condensed by the refrigerant returning from the cryogenic temperature heat exchanger and is separated into a gaseous refrigerant and a liquid refrigerant by the first refrigerant separator And the natural gas is cooled in the cryogenic heat exchanger after each expansion.
Wherein the refrigerant supplied to the low temperature heat exchanger through the first and second refrigerant supply lines is expanded and then supplied to the low temperature heat exchanger to cool the natural gas.
And the expanded refrigerant is mixed with the refrigerant supplied to the low temperature heat exchanger in the cryogenic temperature exchanger and the heat shock preventing means to return to the low temperature heat exchanger.
Wherein the low temperature heat exchanger and the ultra low temperature heat exchanger are PFHE (Plate Fin Heat Exchanger) type heat exchangers.
Wherein the low temperature heat exchanger is a Plate Fin Heat Exchanger (PFHE) type heat exchanger, and the cryogenic heat exchanger is a SWHE (Spiral Wound Heat Exchanger) type heat exchanger.
A low temperature heat exchanger disposed on an upper deck of the floating structure for cooling the natural gas extracted from the gas chill to a low temperature;
A cryogenic heat exchanger disposed on an upper deck of the floating structure for further cooling and liquefying the natural gas cooled in the low temperature heat exchanger;
Temperature shock absorber disposed between the cryogenic heat exchanger and the low-temperature heat exchanger to protect the low-temperature heat exchanger from thermal shock by preventing the cryogenic coolant discharged from the cryogenic heat exchanger from being directly supplied to the low-temperature heat exchanger;
A cold separator for separating the natural gas cooled at a low temperature in the low temperature heat exchanger into a natural gas in a gaseous state and a natural gas in a liquid state and supplying the gaseous natural gas to the cryogenic heat exchanger;
Wherein the natural gas liquefaction apparatus comprises:
A low temperature heat exchanger disposed on an upper deck of the floating structure for cooling the natural gas extracted from the gas chill to a low temperature;
A cryogenic heat exchanger disposed on an upper deck of the floating structure for further cooling and liquefying the natural gas cooled in the low temperature heat exchanger;
Temperature shock absorber disposed between the cryogenic heat exchanger and the low-temperature heat exchanger to protect the low-temperature heat exchanger from thermal shock by preventing the cryogenic coolant discharged from the cryogenic heat exchanger from being directly supplied to the low-temperature heat exchanger;
A cold separator for separating the natural gas cooled at a low temperature in the low temperature heat exchanger into a natural gas in a gaseous state and a natural gas in a liquid state and supplying the gaseous natural gas to the cryogenic heat exchanger;
Wherein the natural gas liquefaction device has a natural gas liquefaction device.
Wherein the floating structure is LNG FPSO.
The natural gas extracted from the gas well is cooled to a low temperature in a low temperature heat exchanger, the natural gas cooled in the low temperature heat exchanger is further cooled in the cryogenic heat exchanger to at least partially liquefy, The refrigerant is further heated by the heat shock prevention means and supplied to the low temperature heat exchanger to protect the low temperature heat exchanger from thermal shock,
Wherein the natural gas cooled at a low temperature in the low temperature heat exchanger is separated into a natural gas in a gaseous state and a natural gas in a liquid state in a cold separator and a natural gas in a gaseous state is supplied to the cryogenic heat exchanger .
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| KR101945473B1 (en) * | 2017-11-16 | 2019-04-17 | 삼성중공업 주식회사 | Reliquefaction system |
| KR20200084540A (en) * | 2019-01-03 | 2020-07-13 | 대우조선해양 주식회사 | Refrigerant Circulation System And Method For Ship |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| KR101336679B1 (en) * | 2012-01-17 | 2013-12-04 | 고등기술연구원연구조합 | Natural gas liquefaction system and startup method thereof |
| KR20220027336A (en) | 2020-08-26 | 2022-03-08 | 삼성중공업 주식회사 | Flow control system used for liquefaction of lng |
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| KR100350934B1 (en) | 1998-12-09 | 2002-08-30 | 에어 프로덕츠 앤드 케미칼스, 인코오포레이티드 | Dual mixed refrigerant cycle for gas liquefaction |
| KR100918201B1 (en) | 2008-11-17 | 2009-09-21 | 대우조선해양 주식회사 | Method and system for reducing heating value of natural gas |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| TW480325B (en) * | 1999-12-01 | 2002-03-21 | Shell Int Research | Plant for liquefying natural gas |
| KR20110076214A (en) * | 2009-12-29 | 2011-07-06 | 지에스건설 주식회사 | Liquefaction of natural gas |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| KR100350934B1 (en) | 1998-12-09 | 2002-08-30 | 에어 프로덕츠 앤드 케미칼스, 인코오포레이티드 | Dual mixed refrigerant cycle for gas liquefaction |
| KR100918201B1 (en) | 2008-11-17 | 2009-09-21 | 대우조선해양 주식회사 | Method and system for reducing heating value of natural gas |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| KR101945473B1 (en) * | 2017-11-16 | 2019-04-17 | 삼성중공업 주식회사 | Reliquefaction system |
| KR20200084540A (en) * | 2019-01-03 | 2020-07-13 | 대우조선해양 주식회사 | Refrigerant Circulation System And Method For Ship |
| KR102552636B1 (en) | 2019-01-03 | 2023-07-07 | 한화오션 주식회사 | Refrigerant Circulation System And Method For Ship |
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| KR20120005158A (en) | 2012-01-16 |
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