RU2386091C2 - Method and device for depleting stream of liquefied natural gas - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: method involves heating a feed stream (1) in a first heat exchange device (5) to form an intermediate feed stream (7), division of the first stream (7) into a first part (17) and a second part (19), passing the first part (17) to a distillation unit (21) and feeding the first part (17) into the distillation unit (21) through a first feed point (25), passing the second part (19) to a second heat exchange device (26) for heating, feeding it into the distillation unit (21) through a second feed point (29), leading the stream (35) of liquid containing natural gas liquid from the bottom part of the distillation unit (21), leading the stream (40) of distillate vapour from the top part of the distillation unit (21), cooling the stream (40) in the second heat exchange device (26) using the second part (19) of the stream (7) to form an intermediate depleted stream (48), part of which is further cooled in the first heat exchange device (5) using the feed stream (1) to form a stream (55) of depleted natural gas. When cooling the stream (40) in the second heat exchange device (26), an intermediate condensate is formed, part (49) of which passes in the distillation unit (21) through a third feed point (51) and intermediate vapour is formed, which passes in the second heat exchange device (5).

EFFECT: use of the invention increases efficiency.

12 cl, 4 dwg, 1 tbl

Description

FIELD OF THE INVENTION

The present invention relates to a method and apparatus for depleting a liquefied natural gas (LNG) stream by separating a gas condensate liquid from a liquefied natural gas stream. The resulting depleted liquefied natural gas stream may be in a liquid state and / or a vapor state into which it passes, for example, using regasification.

In the present description and claims, the term depletion is used in contrast to enrichment and includes the removal of hydrocarbon compounds with a higher molecular weight, as compared to methane, that is, “stretching” or “linearization”. The term gas condensate liquid includes hydrocarbon compounds with a higher molecular weight than methane, including ethane, ethylene, propane, propylene, butane and their isomeric forms, and butylene and its isomeric forms.

State of the art

In addition to methane, liquefied natural gas typically contains higher molecular weight hydrocarbon compounds, including ethane, propane and various isomeric forms of butane. These additional compounds are characterized by a higher calorific value compared to methane. Different markets require liquefied natural gas with different characteristics, especially for calorific value.

If, according to the requirements of pipeline transportation, a low calorific value is required, then there is a need to deplete the liquefied natural gas stream at the regasification plant before transferring the stream to the network. One way to accomplish depletion is to recover the gas condensate liquids from the liquefied natural gas stream.

US Pat. No. 6,604,380 describes such a method for recovering gas condensate liquids. In the described method, the liquefied natural gas feed stream is separated. In figure 2 of the aforementioned US patent, one part of the split stream is heated in a heat exchanger, where it is partially evaporated and then fed to the first separator. The bottom stream, rich in gas condensate liquid, is removed from the first separator and sent to the second separator, which includes a stabilizer. Another part of the split stream bypasses the heat exchanger and is supplied as external irrigation at a very low temperature of approximately -157 ° C (-250 ° F) to the second separator. Methane-rich vapor distillate streams are drawn from the first separator and stabilizer, which are combined and routed through a heat exchanger, where they are cooled using the aforementioned one part of the initial separated stream.

Patent WO 2004/109180 describes a method for processing LNG at a plant in which, due to the action of a heat source, the compressed LNG evaporates, after which it expands and performs work in an open energy cycle.

It is known that the above methods are not effective enough.

Disclosure of invention

An object of the present invention is to minimize the problems described above.

Another objective of the present invention is to provide an alternative method of depletion of a stream of liquefied natural gas.

One or more of the above objectives can be achieved according to the present invention, in a method for depletion of a liquefied natural gas stream by separating a gas condensate liquid from a liquefied natural gas stream, said method at least comprising the following steps:

- heating the feed stream containing a stream of liquefied natural gas in the first heat exchange device, which is done with the aim of forming an intermediate feed stream;

- separation of the intermediate feed stream, at least in the first part and second part;

- the passage of the first part to the distillation unit and the supply of the first part to the distillation unit through the first supply point;

- the passage of the second part to the second heat exchanger, where the second part is additionally heated and then fed to the distillation unit through the second supply point;

- diversion of the fluid stream containing the gas condensate liquid from the bottom of the distillation unit;

- diversion of the vaporous distillate stream from the top of the distillation unit;

- the passage of the vaporous distillate stream to the second heat exchange unit, where it is cooled using the second part of the intermediate feed stream, resulting in the formation of an intermediate lean stream, at least a portion of which then passes into the first heat exchange device and is further cooled by the feed stream and is formed lean natural gas stream;

where when the vaporous distillate stream is cooled in the second heat exchanger, it partially condenses and an intermediate condensate forms, at least part of which passes into the distillation unit through the third supply point and intermediate vapor forms, which passes into the first heat exchanger.

An advantage of the present invention is that it provides greater flexibility in the selection of the temperature profile in the distillation unit, which contributes to the effective management of the processing conditions in the distillation unit.

It further turns out that using an intermediate lean stream to form an irrigation stream significantly improves the recovery of gas condensate liquid. The vapor distillate stream from the distillation unit partially condenses upon cooling in the second heat exchanger, and the intermediate lean stream contains intermediate condensate that can pass into the distillation unit through a third supply point, and intermediate steam that can pass into the first heat exchanger.

Another advantage is that the intermediate condensate is enriched with heavier components, including gas condensate liquids. Instead of supplying this condensate to the first heat exchanger, it is re-fed to the distillation unit as internal irrigation. Therefore, the recovery of the gas condensate liquid is significantly improved.

Choosing mutual cooling in the first and second heat exchangers, it is possible to choose an intermediate temperature in the intermediate lean stream, which allows you to adapt the composition of the condensate.

Another advantage of the present invention is that the heating and cooling of the stream before and accordingly after passing through the distillation unit is carried out in at least two stages. Thus, the resulting intermediate between at least two stages of the threads can be used in the considered method in addition to fully heated and accordingly cooled flows.

One way to use the intermediate feed stream is through external irrigation, the temperature of which is lower than the temperature of the portion supplied to the distillation unit through the second feed point, but not as low as the temperature of the feed stream.

It turns out that for the effective separation of the components of the gas condensate liquid from the liquefied natural gas, external irrigation is usually not required, the temperature of which is equal to the temperature of the liquefied natural gas (approximately -157 ° C, or below -140 ° C). An advantage of the present invention is that the temperature of the external irrigation can be selected at a higher temperature of the feed stream, for example, above -140 ° C. As a result, equipment such as a distillation plant or reboiler (if equipped) may be smaller or less energy needs to be dissipated in the reboiler. Thus, the very low temperature of the feed stream can be fully used for re-condensation of depleted natural gas.

Depending on the degree of heating used in the first heat exchanger and the pressure of the feed stream, the intermediate feed stream may be either completely liquid or partially steam.

When heating the feed stream in the first heat exchanger results in partial evaporation of the feed stream, wherein the intermediate feed stream contains a mixture of the liquid fraction of the intermediate feed stream and the vapor fraction of the intermediate feed stream, it is advisable to separate at least the liquid fraction of the intermediate feed stream on the first and second parts. The vaporous fraction of the intermediate feed stream due to the relatively low temperature compared with the temperature after the second heating is almost no gas condensate liquids and it does not need to be subjected to additional distillation. It can be mixed with the final product stream.

According to another aspect of the present invention, there is considered a depleted natural gas stream obtained by a method according to the present invention, as well as a device suitable for implementing the method according to the present invention.

Preferred embodiments of the device are obtained from preferred embodiments of the method and / or from a detailed description of the embodiments set forth below.

The above and other features of the present invention will be further illustrated by way of example with reference to the accompanying drawings, not limiting the invention.

Brief Description of the Drawings

In the attached drawings:

1 and 2 are views schematically showing block diagrams and an apparatus that do not contain all the distinguishing features of the present invention, but which are incorporated herein for illustrative purposes;

FIG. 3 is a view schematically showing a block diagram and an apparatus according to the present invention; FIG. and

FIG. 4 is a view schematically showing a preferred embodiment of the present invention, where the block diagram of FIG. 2 is combined with the block diagram of FIG. 3.

In the present description, the same reference position correspond to the same parts. Reference numbers corresponding to pipelines are also used to refer to corresponding flows passing through said pipelines.

Detailed Description of Drawings

Figure 1 schematically shows a device designed to deplete a stream of liquefied natural gas, providing the extraction of gas condensate liquid from the specified stream of liquefied natural gas. Raw pipe 1 is connected to a source of liquefied natural gas. The feed pipe 1 may comprise a pump 3, the outlet on the high pressure side of which is connected to the first heat exchanger 5 by means of the pipe 2.

An intermediate feed pipe 7 connects the first outlet 6 of the first heat exchanger 5 to the distribution device 14. Two outlet openings of the distribution device 14 are connected to the pipelines 17 and 19. If desired, the distribution device 14 may comprise more than two outlet openings. The pipe 17 is connected to the distillation unit 21 by means of an optionally present first control valve 23 and a first supply point 25 located at the top of the distillation unit 21. Another pipe, pipe 19, is also connected to the distillation unit 21, but through the second heat exchange device 26, the pipe 20 and a second supply point 29, while the pipe 26 may be provided with a second control valve 27. Thus, the first outlet 6 of the first heat exchanger 5 is connected to the second heat exchanger 26. The pipe 17 bypasses the second heat exchanger 26. Preferably, the second supply point 29 of the distillation unit 21 is located below the first supply point 25.

The bottom of the distillation unit 21 is provided with an outlet 31 for diverting a fluid stream 35 from the distillation unit 21. Optionally, the reboiler 33 may be located in the pipe 35, in which case it is connected to the outlet 31. The return pipe 37 of the reboiler is directed back from the reboiler 33 to the bottom of the distillation unit 21. Optionally, the reboiler 33 present may be part of the distillation unit 21, and not be an external device, as shown. A pipe 38 is connected to a pipe 35 or an optionally present reboiler 33 and is designed to remove gas condensate liquid.

The upper part of the distillation unit 21 is provided with an outlet 39 of the vaporous distillate. The outlet of the vaporous distillate 39 is connected to the first heat exchanger 5 through the second heat exchanger 26. The pipe 40 is placed between the outlet 39 of the vaporous distillate and the second heat exchanger 26 and connected to the pipe 48, which is located between the second heat exchanger 26 and the first heat exchanger 5, and connected to a conduit 55 located downstream of the first heat exchanger 5 using the second outlet 41 of the first heat exchange device 5.

An optionally present pump 65 may be contained in conduit 55, which enters conduit 67 and which is designed to increase pressure in order to obtain a depleted liquefied natural gas stream at a pressure corresponding to particular specifications. Pipeline 67 can be connected to any type of regasification system, including those described in Innovative gas processing with various LNG sources, by Joseph Cho et al., Published in the LNG Journal January / February 2005 , pp. 23-27, the contents of this article are incorporated herein by reference.

The device described above is capable of depleting a liquefied natural gas stream, which is done by separating the gas condensate liquid from the liquefied natural gas stream. An optionally present bypass pipe 59 is for connecting a pipe 1 or an outlet on the high pressure side of a pump 3 located upstream of the first heat exchanger 5 and a pipe 55 located downstream of the first heat exchanger 5. Optionally, the bypass 59 can be equipped with a control valve 61. Thanks to the bypass pipe 59, it is possible to bypass the depletion device and not to separate the gas condensate liquid.

The device of figure 1 works as follows. The feed stream containing the liquefied gas stream is fed through the feed pipe 1 and heated in the first heat exchanger 5 using the intermediate lean stream located in the pipe 48, resulting in an intermediate feed stream 7. Before the feed stream 1 is supplied to the heat transfer device 5, the pressure of said the feed stream 1 can be increased by using the optionally present pump 3. This operation is especially useful when the liquefied natural gas is supplied at atmospheric pressure or near atmospheric pressure.

The intermediate feed stream 7 is separated in the distribution device 14, at least into the first part 17 and the second part 19. The first part 17 passes to the distillation unit 21 and is fed into it through the first supply point 25. Pressure and temperature can be controlled using control valve 23.

The second part 19 of the intermediate feed stream 7 passes to a second heat exchanger 26, where it is additionally heated by the distillate stream from line 40. The resulting additionally heated stream is subsequently fed to the distillation unit 21 through line 20 and a second supply point 29. Pressure can be controlled using control valve 27.

During additional heating in the second heat exchanger 26, the second part 19 of the intermediate feed stream 7 is at least partially vaporized. It is generally recommended that at least 60% of the molar flow is evaporated.

Since the temperature of the first part 17 may be lower than the temperature of the second part 19, the first part 17 acts as an external irrigation stream in the distillation process. This helps to purify the gas condensate liquid from the vapor obtained from the second part 19, as well as from the optionally present reboiler 33. The cleaning is facilitated by the fact that the first supply point 25 is located above the second supply point 29.

The liquid stream containing the gas condensate liquid is then diverted from the lower part of the distillation unit 21 through the outlet 31 to the pipe 35. If desired, the liquid stream is heated and partially fed back through the pipe 37 to the lower part of the distillation unit 21 to form a certain amount of steam containing relatively light molecules. The residue is discharged in the form of a gas condensate liquid into the pipeline 38.

On the other hand of the distillation unit 21, the vaporous distillate stream 40 is diverted from the top of the distillation unit 21. The vaporous distillate stream 40 is a depleted stream containing mainly methane and also sometimes other components, such as, for example, ethane and propane residues.

The vapor distillate stream 40 passes to a second heat exchanger 26, where it is cooled by an intermediate feed stream and an intermediate lean stream 48 is formed, at least a portion of which is further passed to the first heat exchanger 5 and further cooled by a feed stream 1, resulting which results in a depleted natural gas end stream 55. The final stream 55 can be completely re-liquefied.

If desired, the final stream 55 is combined with the bypass stream drawn from the feed stream 2 through the pipe 59. Further, the pressure of the final stream in the pipe 55 can be increased to the required level using an optionally present pump 65, which is usually more efficient from the point of view of energy consumption, so as flow in conduit 55 is usually completely liquefied. The final stream is discharged through line 67, after which it can undergo additional processing (not shown), for example, regasification can be carried out by heating, which is done with the aim of converting it into a gaseous stream. Several possible regasification methods are described in an article from the LNG Journal January / February 2005 mentioned earlier.

Although not necessary, a compressor (not shown) may be located in conduit 40 to provide a convenient pressure boundary so that the final flow in conduit 55 exiting the first heat exchanger 5 through the outlet 41 is not only completely re-liquefied, but also to some extent underheated. This is less important when a significant part of the feed stream 2 can be bypassed through line 59, since in this case the final stream exiting the first heat exchanger 5 undergoes direct heat exchange.

The advantage of having two heat exchange devices 5, 26 is that in this case, intermediate streams 7 and / or 48 can be used during the processing process. In the embodiment of FIG. 1, a part (first part 17) of the intermediate stream 7 is used as external irrigation, the temperature of which is lower than the temperature of the part (second part 19), which is supplied to the distillation unit 21 through the second supply point 29, but not low as the temperature of the feed stream 1. Due to the correct balance of the heat capacity of the first heat exchanger 5 compared to the second heat exchanger 26, better control of the temperature of the irrigation stream 17 is achieved and additional agretogo feed stream 20 when compared to the process described in patent US 6604380. This improved flexibility allows to effectively regulate the processing mode in distillation unit 21 to achieve the desired separation of the distillate stream 40 and bottom stream 38 of the selected component gas liquids.

FIG. 2 is based on an embodiment, which is shown and explained above with reference to FIG. 1, and depicts a gas / liquid separator 9 (in the claims referred to as a “second gas / liquid separator”) that is connected to a first outlet 6 of the first heat exchange devices 5 and distribution device 14. Here, the gas / liquid separator is made in the form of a vessel 9 for separating the feed stream. The first exhaust device 6 of the first heat exchange device 5 is connected to a vessel 9 for separating the feed stream. The vessel 9 for separating the feed stream contains a lower outlet 11 and an outlet 13 of the distillate. The lower outlet 11 is connected to the distribution device 14 by a pipe 15. The outlet 13 of the distillate is connected to the pipe 48 through a pipe 57, which is located upstream relative to the first heat exchange device 5.

The embodiment of FIG. 2 works as follows. When the feed stream is heated in the first heat exchanger 5, it partially evaporates. The steam is drawn from the outlet 13 of the distillate and combined with the intermediate lean stream in conduit 48. Next, the combined streams are further cooled and re-condensed in the first heat exchanger 5 using the feed stream 2.

Since the temperature is still relatively low, the steam will contain predominantly poorer components, such as methane. Components with a higher calorific value, such as propane, will be essentially completely in the liquid phase along with ethane and methane. The vaporous fraction does not need to be further subjected to distillation and it can be mixed with the distilled stream in line 48 for subsequent re-condensation in the first heat exchanger 5.

Typically, the proportion of steam in moles is from 1 to 90%. The larger the proportion of steam in moles, the less the load from its own mass on the separation device located downstream. In this regard, for a typical composition of a liquefied gas, it is preferable that at least 50% of the molar mass is in the vapor phase. On the other hand, the larger the vapor fraction in moles, the lower the extraction of gas condensate liquids, since the separation by weight in the vessel is not as good as in the distillation unit 21. Therefore, it is preferable that the vapor fraction in moles does not exceed 80% .

The liquid that is drawn from the lower outlet 11 of the separator 9 is directed to a distribution device 14, where part of it is sent to the distillation unit 21 through a pipe 17 as an external irrigation, thereby costing a second heat exchange device 26.

An advantage of the present embodiment is that the external irrigation is completely liquid, so that it is very effective as a cleaning medium. The temperature of the external irrigation is lower than the temperature of the part supplied to the distillation unit through the second supply point 29, but not as low as the temperature of the initial feed stream 1. The temperature can be controlled by choosing the heat transfer in the first heat exchange device 5, if desired also depending on expansion values in control valve 23 or by adjusting the last value.

The advantage of having the optionally present control valves 23 and 27 is that the distillation unit 21 operates at a pressure lower than the pressure in the feed stream separator 9, which improves the separation efficiency of the gas condensate liquid components in the installation 21.

As shown in FIG. 2, the optionally present distillate compressor 63 may be located between the outlet 39 of the vaporous distillate of the distillation unit 21 and the second heat exchanger 26. This can compensate for the optionally present differential pressure across valves 23 and 27, thereby the pressure in line 48 can reach the level that is established by the feed stream in the pipeline 7.

It is preferable that the compressor 63 is located upstream relative to the second heat exchanger 26, since the distillate stream 40 is always completely composed of steam due to the distillation unit 21, while the final stream downstream of the second heat exchanger 26 may consist of several phases.

Alternatively, an expansion device, such as a Joule-Thompson valve (not shown), may be provided in line 57 to reduce pressure in line 57 to pressure in line 48. Now, after explaining the process diagrams of FIG. .1 and 2, we turn to FIG. 3, which shows an embodiment of the present invention based on the embodiment shown and explained with reference to FIG. 1, where the internal irrigation system is placed in the pipe 48 between the outlet 39 of the vapor distillate of the distillation unit and the first heat exchanger 5. The irrigation system shown here comprises a gas / liquid separator (referred to in the claims as “first gas / liquid separator”), which is here in the form of an irrigation flow separation vessel 43. An irrigation flow separation vessel 43 is located downstream of the second heat exchanger 26 in the conduit 48 and is connected to the second heat exchanger 26 via the conduit 42. The separator 43 includes a lower outlet 45 and a distillate outlet 47. The lower outlet 45 is connected to the distillation unit 21 via a pipe 49 and a third supply point 51, which is necessary to ensure irrigation flow. An optionally present control valve 53 may be located in conduit 49. It is advisable that the third supply point 51 is higher than the second supply point 29, since the temperature of the irrigation stream 49 is usually lower than the temperature of the additionally heated feed stream 20, and it is advisable that the third point 51 feed was located below the first point 25 of the feed.

The outlet 47 of the distillate of the vessel 43 of the separation of the irrigation flow is connected to the first heat exchanger 5 through a pipe 48.

In operation, when a feed stream of liquefied natural gas containing methane, ethane and propane is supplied for processing according to the method in question, most of the propane is recovered in the distillation unit 21. Selective recovery of propane can be increased if the remaining components that contain propane and which may be present in the vaporous distillate stream 40, condense in the second heat exchanger 26. The intermediate condensate 49 is drawn from the reflux separation vessel 43 current and fed back to distillation column 21 as a cold reflux stream. Propane has another opportunity to exit the processing through the outlet 31.

Since the second heat exchanger 26 brings the intermediate depleted flow only to an intermediate temperature, the mass selectivity of the irrigation flow can be adjusted by selecting the indicated temperature, and also, if desired, by using the pressure drop in the optionally present valve 53. This can be avoided. unnecessary circulation of methane or ethane through the installation, thereby simply saving energy, but not increasing the production of lean natural gas coming out of the processing process through pipes wire 55.

When comparing the process diagram with FIG. 1 (not containing all the distinguishing features of the present invention) and the process diagram with FIG. 3 (corresponding to the present invention), calculations calculating propane extraction show that with the process diagram of FIG. 1 at a given implementation mode the process of propane recovery is 69%, and in the same mode, in the process diagram of FIG. 3, propane recovery is 90%.

Typically, the proportion of steam in moles can range from 50 to 95%. The greater the proportion of steam in moles, the better, the lower the number of poor components circulating in the irrigation cycle. In this regard, it is preferable that at least 60% of the molar flow is in the vapor phase. On the other hand, the higher the fraction of vapor in moles, the lower the recovery of gas condensate liquids, since the smaller component of the gas condensate liquid is re-condensed and fed back to the distillation unit 21. In this regard, for the most typical liquefied natural gas compositions, it is preferable that the fraction of vapor in moles was not more than 90%.

FIG. 4 shows a preferred embodiment according to the present invention, in which the processes and devices shown in FIGS. 2 and 3 are combined. For a detailed description, see the above descriptions of FIGS. 1, 2 and 3.

The following table 1 shows the lower and upper boundaries of the temperatures and pressures of flows in various pipelines, as well as a typical value of temperature and pressure in a specific operation example.

Table 1 Pipeline Lower boundary T (° C) The upper limit of T (° C) T (° C) Lower border P (bar) Upper border P (bar) P (bar) one -162 -120 -161 1.0 1.5 1.1 2 -162 -120 -161 5 fifty 33 7, 15, 17, 57 -140 -fifty -81 5 fifty 33 twenty -70 -twenty -37 5 fifty 33 38 -10 150 90 2 45 29th 40 -90 -10 -28 2 45 29th 42, 48, 49 -60 -thirty -49 5 fifty 33 55 -110 -162 -128 5 fifty 33 66 -40 0 -19 5 fifty 33 67 -110 -162 -140 twenty 140 70

In the example to which Table 1 relates, the proportion of steam in moles in line 7 was 66%, and in line 42 it was 69%. The proportion of steam in moles in line 20 was 75%. Calculations based on mass balance show that the device and process of FIG. 4 provide effective means for extracting components of a gas condensate liquid from a feed stream of liquefied natural gas in excess of 90%.

In the context of the present description, heat exchangers may comprise one heat exchanger or several heat exchangers arranged in parallel and / or in series.

Claims (12)

1. A method of depleting a stream (1) of liquefied natural gas by separating a gas condensate liquid (35) from a stream of liquefied natural gas, comprising at least the following steps:
heating the feed stream (1) containing the liquefied natural gas stream in a first heat exchange device (5), which is done to form an intermediate feed stream (7);
dividing the intermediate feed stream (7) into at least a first part (17) and a second part (19);
the passage of the first part (17) to the distillation unit (21) and the supply of the first part (17) to the distillation unit (21) through the first supply point (25);
the passage of the second part (19) to the second heat exchange device (26), where the second part is additionally heated and then fed (20) to the distillation unit (21) through the second supply point (29);
diversion of the fluid stream (35) containing the gas condensate liquid from the bottom of the distillation unit (21);
diverting a stream (40) of vaporous distillate from the upper part of the distillation unit (21);
the passage of the vapor distillate stream (40) into the second heat exchange unit (26), where it is cooled by the second part (19) of the intermediate feed stream (7), as a result of which an intermediate lean stream (48) is formed, at least a portion of which is further passes into the first heat exchange device (5) and is additionally cooled by the feed stream (1) and a depleted natural gas stream (55) is formed;
where when the vapor stream of the distillate in the second heat exchange device (26) is cooled, it partially condenses and an intermediate condensate forms, at least part (49) of which passes into the distillation unit (21) through the third supply point (51) and an intermediate steam that passes into the first heat exchanger (5). 2. The method according to claim 1, in which heating the feed stream in the first heat exchange device (5) leads to partial evaporation of the feed stream, wherein the intermediate feed stream (7) contains a mixture of the liquid fraction of the intermediate feed stream and the vaporous fraction of the intermediate feed stream, and wherein at least a portion of the liquid fraction (15) of the intermediate feed stream is divided into at least the first (17) and second (19) parts. 3. The method according to claim 2, in which the mixture passes into a vessel (9) for separating the feed stream, from which the liquid fraction (15) of the intermediate feed stream and the vaporous fraction (57) of the intermediate feed stream are respectively stretched to separate the stream, at least on the first (17) and second (19) parts. 4. The method according to claim 1, wherein the second supply point (29) is located below the first supply point (25). 5. The method according to claim 1, wherein the third supply point (51) is located below the first supply point (25). 6. The method according to claim 1, wherein the third supply point (51) is located above the second supply point (29). 7. The method according to claim 1, in which the stream (40) of vaporous distillate is compressed before passing into the second heat exchange device (26). 8. The method according to claim 1, wherein the depleted natural gas stream is subsequently regasified. 9. The depleted liquefied natural gas stream obtained according to the method according to any one of claims 1 to 8. 10. A device for depleting a stream (1) of liquefied natural gas by separating a gas condensate liquid (35) from a stream of liquefied natural gas, said device comprising at least the following:
a first heat exchange device (5), which is adapted to receive a feed stream (1) containing a stream of liquefied natural gas, and which contains an outlet (6) for discharging an intermediate feed stream (7);
a second heat exchange device (26) connected to an outlet (6) of the first heat exchange device (5);
a distillation unit (21), which contains at least a first, second and third points (25, 29, 51) of supply, the lower part is provided with an outlet (31) designed to divert the flow (35) of the liquid containing the gas condensate liquid, and the upper part is provided with an outlet (39) of the vaporous distillate and is connected to the first heat exchange device (5), at least through a second heat exchange device (26);
a distribution device (14) connected to an outlet (6) of the first heat exchange device (5), a distribution device (14) comprises a first outlet device (6) connected to a first supply point (25) of the distillation unit (21) and contains a second outlet an opening connected to a second supply point (29) by a second heat exchange device (26); and
a first gas / liquid separator (43) located downstream of the outlet (39) of the vaporous distillate and between the second heat exchanger (26) and the first heat exchanger (5), the first separator (43) comprises an outlet (45) connected with a third point (51) of the distillation unit (21), and an outlet (47) connected to the first heat exchange device (5). 11. The device according to claim 10, additionally containing a second gas / liquid separator (9), the inlet of which is connected to the outlet (6) of the first heat exchanger (5), and the lower outlet (11) of which is connected to the distribution device (14) . 12. The device according to any one of claims 10 and 11, further comprising a compressor (63) located between the outlet (39) of the distillation unit (21) and the second heat exchange device (26).

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