EP3423343A1

EP3423343A1 - Method for operating a liquefied gas tank and liquefied gas tank for receiving lng and boil-off gas

Info

Publication number: EP3423343A1
Application number: EP17710121.9A
Authority: EP
Inventors: Jürgen Essler; Thomas Tiedemann; Andreas Hambücker; Hans-Christian HAARMANN-KÜHN
Original assignee: TGE Marine Gas Engineering GmbH
Current assignee: TGE Marine Gas Engineering GmbH
Priority date: 2016-02-29
Filing date: 2017-02-14
Publication date: 2019-01-09
Also published as: JP6994464B2; DE102016002316A1; JP2019512072A; WO2017148571A1; US20190056063A1; KR20180115313A; SG11201807395WA; KR102177084B1; CN108778921A

Abstract

The invention relates to a method for operating a liquefied gas tank (1) with a tank volume (2) for receiving LNG and boil-off gas (BOG), wherein a gaseous BOG stream and a liquid LNG stream are fed to the tank volume, and wherein the BOG stream is introduced into the LNG stream. Subsequently, the resulting BOG-LNG mixture is introduced into the tank volume. The invention also relates to a corresponding liquefied gas tank.

Description

Method for operating a liquefied gas tank and

LPG tank for holding LNG and boil-off gas

The invention relates to a method for operating a liquefied gas tank and a liquefied gas tank with a tank volume for holding liquid natural gas (LNG) and boil-off gas (BOG), and a floating storage unit (FSU), an LNG carrier, a Regas -Barge, an LNG-powered vehicle and an LNG-powered power plant, each with such a liquefied gas tank.

LPG storage tanks for LNG are used, inter alia, as transport tanks in LNG carriers or as buffer storage tanks (for example FSUs or Regas barges), for example after overseas transport before being fed into a consumer network, or as storage tanks (for example in LNG-operated marine vessels). and land vehicles or in stationary gas power plants).

Regardless of the nature of the use of the LPG tank, the LNG contained therein, despite the use of extensive heat insulation measures due to the large difference in temperature to the air of the environment of the tank is basically exposed to a slow but steady warming.

The further this heating of the LNG progresses, the greater the proportion of the stored LNG which transitions from the liquid to the gaseous phase and thus, as a so-called BOG, increases the internal pressure in a tank volume of the liquid gas tank. As with warming, this increase in pressure is slow but steady. If countermeasures are not taken in a timely manner, sooner or later, depending on the tank construction, there will be a risk of breakage of the tank shell.

Therefore, in known liquefied gas tanks, there is normally a possibility to drain the BOG and then either burn it free or supply it to a consumer.

Solutions are also known in which the BOG is compressed, liquefied again and then returned as LNG in the tank volume of the LPG tank. However, the solutions known for this require complex and space-consuming processing cycles for the LNG and / or the BOG to bring the latter back into the liquid phase.

For example, US Pat. No. 3,733,838 discloses a system for reliquefying BOG in which liquid LNG is taken from the tank, heated by means of a heat exchanger and a heater, and converted into the gaseous phase. This gaseous LNG is then mixed with the also derived from the tank BOG, cooled in the aforementioned heat exchanger and introduced after passage of an expansion valve in the liquid phase back into the tank. This process requires a heat exchanger that limits the flexibility of piping and an active heater that runs counter to the goal of minimizing heat energy and thus pressure build-up in the tank.

Although another solution according to European Patent Application EP 1 956 287 A2 does not require active heating, it requires two separate fluid circuits in order to provide the required condensation performance. In the first cycle BOG is injected from the upper part of the tank into the lower part of the tank; In the second cycle LNG is sprayed from the lower part of the tank in the upper part of the tank. The necessary condensation is thus achieved by two final measures provided separately from each other, both of which must be laboriously installed on the tank and in the tank.

An object of the invention is now to provide a sufficient capacity for the liquefaction of BOG in a simpler manner.

This object is achieved by means of a method having the features of independent claim 1 and by means of a liquefied gas tank having the features of independent claim 7. An FSU, an LNG carrier, a Regas barge, an LNG-powered vehicle and an LNG-powered power plant are put in claim 15 under protection.

According to one aspect of the invention, a method for operating a liquefied gas tank having a tank volume for receiving LNG and boil-off gas (BOG) is proposed, wherein a gaseous BOG stream and a liquid LNG stream are supplied to the tank volume. In the process, the BOG stream is introduced into the LNG stream and then the resulting BOG-LNG mixture is introduced into the tank volume.

According to a further aspect of the invention, a liquefied gas tank having a tank volume for receiving LNG and boil-off gas (BOG) is proposed, which is a BOG guide for guiding gaseous BOG and an LNG guide for guiding liquid LNG. Here, the BOG guide and the LNG guide lead into a common BOG-LNG guide, which is designed to guide BOG-LNG mixture and flows into the tank volume.

In particular in order to be able to use the invention as widely as possible and / or to increase its advantages by applying the invention at several points in a liquefied gas supply chain, according to further aspects of the invention, an FSU, an LNG carrier, a Regas barge , an LNG-powered sea or land vehicle or an LNG-powered power plant, each proposed with at least one liquefied gas tank according to the invention.

By means of a design according to the invention, it is possible with a reduced space requirement and a minimized requirement for line and thermal management components to achieve a BOG liquefaction process that is structurally very simple to implement and that can additionally facilitate improved liquefaction performance. In addition, a liquefied gas tank can be provided, which requires a smaller number of openings in the tank shell.

The invention is based on the idea of providing the union of the liquid LNG and the gaseous BOG as far upstream as possible in the liquefaction cycle while ensuring that the BOG is introduced into passing LNG, and not dormant LNG. As a result, on the one hand, a heat input along superfluous pipelines can be eliminated and, on the other hand, the uptake and condensation of the gaseous BOG in the liquid LNG can be simplified.

Pressing the BOG into the LNG stream works the better the stronger the pressure of the BOG stream is above a saturation pressure of the LNG stream. Whether the pressure in the BOG flow is increased upstream by a compressor, or the BOG from another tank (synonymous memory) is fed directly, in which it is already under a - relatively speaking - high pressure is irrelevant.

The condensation of the initially gaseous BOG after introduction into the LNG stream works the better, the more strongly the subcooling of the LNG stream - based on the pressure conditions in the tank volume of the liquid gas tank - is pronounced. As long as the LNG stream is undercooled in this sense, the introduced BOG stream can be condensed (synonymous: condensed, redeemed, pressed in, pressed). - -

The operation of a liquefied gas tank in the sense of the invention may involve both filling and emptying of its tank volume with LNG and / or BOG, as well as a storage operation, whereby over time the rising tank pressure caused by an increasing BOG fraction must be counteracted. In the present case, the term "operation" thus includes both a change in the filling quantity of LNG and / or BOG (and thus usually also a BOG pressure change), as well as a pressure regulation in the case of essentially constant filling quantity.

Boil-off gas (BOG) in the present case is to be understood as gaseous LNG, in particular that which has changed from the liquid phase into the gaseous phase due to the changing temperature or pressure environment in a tank. Within the meaning of the invention, BOG can be "produced" in the tank volume of a liquefied gas tank according to the invention or a further development, but can also come from a conventional tank from which the tank volume was filled in the sense of the invention.

For the purposes of the invention, a guide means, in particular, a pipeline or an assembly of a plurality of pipelines, wherein the pipelines are preferably set up to transport LNG and / or BOG under the transport of liquid gas under normal temperature and / or pressure conditions. If appropriate, corresponding reinforcements and / or insulations may be provided for this purpose.

In order to be able to load the liquefied gas tank using a method in accordance with the invention and thereby additionally save space and possibly line components, according to a preferred development, at least part of the BOG for the BOG stream and / or at least part of the LNG for the LNG stream supplied to the liquefied gas tank from outside the tank volume, in particular from at least one connected storage of a floating storage unit (FSU) or an LNG carrier or a Regas barge. For this purpose, loading guides for BOG and / or LNG are preferably provided.

Various functions in the operation of the liquefied gas tank, such as the loading and the pressure regulation for the already in the liquefied gas tank BOG, can be combined with it or carried out simultaneously.

According to a preferred development, at least part of the BOG for the BOG stream and / or at least part of the LNG for the LNG stream from the tank volume of the Liquefied gas tanks taken even, in particular to be able to perform a pressure regulation within the tank volume also independent of a charging or discharging process. For this purpose, circulation guides for BOG and / or LNG are preferably provided, in which the BOG and the LNG stream are combined in the sense of the invention.

As a result, the pressure and / or temperature conditions within the tank volume can be kept longer in a desired range.

Preferably, LNG is pumped from a lower region of the tank volume by means of a pump into an LNG guide and / or BOG is sucked out of an upper region of the tank volume by means of a BOG guide and a compressor arranged therein. The resulting streams of LNG or BOG are then preferably combined with one another in the sense of the invention.

In order to be able to perform a pressure regulation in the liquefied gas tank as flexibly and finely adjustable as possible, the BOG flow BOG is supplied from the tank volume and from at least one connected storage and / or LNG flow from the tank volume and from at least one LNG flow connected memory supplied.

Preferably, it is provided that the loading guides (synonym filling arrangements) and / or the recirculation guides (synonymously circulating circuits) are designed to run into one another and can open into the tank volume together. For example, in the flow direction, first the LNG loading guide and the LNG circulation guide on the one hand and the BOG loading guide and the BOG circulation guide can be combined and then the combined LNG guide and the combined BOG guide are brought together in the sense of the invention.

In order to be able to condense also not located in the BOG stream BOG, the BOG-LNG mixture is introduced above a LNG filling level of the tank volume in gaseous BOG, in particular sprayed according to a preferred embodiment. Preferably, during introduction, the entire BOG-LNG mixture guided in a common BOG-LNG guide is already present in the liquid phase and / or is still preferably undercooled with respect to the pressure conditions despite the already initiated introduction of relatively warmer BOG in the tank volume. Additionally or alternatively, the BOG-LNG mixture is introduced according to a preferred development below an LNG filling level of the tank volume in liquid LNG. This can allow optimum mixing of the contents of the tank volume, in particular with regard to a temperature distribution.

So that the liquefied gas tank can be filled by means of a common BOG-LNG guide according to the invention and thus to save additional space and possibly line components, according to a preferred development, the BOG guide and / or the LNG guide, in particular its tank volume distal end, a fluid interface to at least one connectable memory, in particular a floating storage unit (FSU) or an LNG carrier or a Regas barge, and / or is adapted to supply the tank volume BOG or LNG from a connected memory.

Such a fluid interface can be designed as an LNG interface and / or as a BOG interface, depending on which type of guide it terminates. It can also be an interface standardized for handling LNG or BOG, but also an interface adapted to the connection of a specific type of storage to the liquefied gas tank.

In order to allow pressure regulation in the tank volume independently of a filling process, the BOG guide is set up to remove gaseous BOG from the tank volume above an LNG fill level and / or the LNG guide is set below an LNG fill level remove liquid LNG from the tank volume.

In the context of the invention, an LNG fill level can be, for example, a predetermined fill level and / or a height range that indicates the maximum and minimum fill levels of the tank volume with liquid LNG. Preferably, in the second case, a BOG guide for taking BOG is located above an upper limit of the altitude range (because normally BOG is always there), and an LNG guide for taking LNG below a lower limit altitude range (because there usually LNG is always located).

In order to be able to condense BOG, which is not in the BOG stream, the mouth of the common BOG-LNG guide into the tank volume above one, in particular predetermined, LNG filling level of the tank volume arranged.

Preferably, the mouth has a spray nozzle for spraying the BOG-LNG mixture, in particular in order to achieve an optimized condensation effect with respect to the BOG located above the LNG filling level.

Additionally or alternatively, the mouth of the common BOG-LNG guide is arranged in the tank volume below a, in particular predetermined, LNG filling level of the tank volume in order to achieve optimal mixing of the liquid LNG in the tank volume, in particular with regard to a uniform temperature distribution.

In order to reduce the piping necessary for integration into the consumer or consumer networks, the LNG guide according to a preferred development has an interface to a customer / consumer network, which is configured to transfer LNG from the tank volume into the customer A / to feed in the food network. For the same reason, the BOG-guide according to a preferred embodiment, an interface to a customer A / consumer network, which is set up to feed BOG from the tank volume in the customer-A consumer network.

Advantageous embodiments of the various aspects of the invention are the subject of the dependent claims. Other features, advantages and applications of the invention will become apparent from the following description taken in conjunction with the figures, wherein similar components may be identified in different figures with the same reference numerals. They show, partly in a highly schematic representation,

Figure 1 is a sectional view of a liquefied gas tank according to an embodiment of the invention with an external supplied BOG-LNG guide.

2 shows a sectional view of a liquefied gas tank according to a further embodiment of the invention with a BOG-LNG guide supplied from the tank volume;

Fig. 3 is a sectional view of a liquefied gas tank according to another embodiment of the invention, in which the BOG guide and the LNG guide are completely disposed within the tank shell; Fig. 4 is a sectional view of a liquefied gas tank according to another embodiment of the invention wherein the BOG-LNG mixture is compressed below the LNG fill level;

5 shows a sectional view of a liquefied gas tank according to a further embodiment of the invention, to which a couplable transport tank and collector networks are connected;

6 shows in a sectional view a liquefied gas tank, which differs from that according to FIG. 5, in particular in that the BOG-LNG mixture is compressed below the LNG filling level; and

Fig. 7 in a sectional view of a liquefied gas tank, to which in addition to a dockable transport tank and customer networks and a permanently installed storage tank is connected.

FIG. 1 shows a liquefied gas tank 1 with a tank volume 2, in which the invention is applied to a filling arrangement 3.

The liquefied gas tank 1 is delimited by a tank shell 4, which is thermally insulated from the environment of the liquefied gas tank 1 by means of a heat insulating layer 6. The liquefied gas tank 1 is filled up to an LNG filling level 8 with liquid LNG 10; above the LNG filling level 8, the liquefied gas tank 1 is filled with gaseous BOG 12.

The liquefied gas tank 1 has a BOG guide 14 for guiding gaseous BOG, via which the tank volume 2 BOG can be supplied from an external source. In addition, the liquefied gas tank 1 has an LNG guide 16 for guiding liquid LNG, via which the tank volume 2 LNG can be supplied from an external source. For sufficient promotion or compression, a guide compressor 18 is installed in the BOG guide 14 and a guide pump 20 in the LNG guide 16 in this embodiment.

In each case downstream of the guide compressor 18 and the guide pump 20, a junction 22 is provided, at which a pipe element of the BOG guide 14 and a pipe element of the LNG guide 16 open into a common BOG-LNG guide 24. The common BOG-LNG guide 24 is in the exemplary embodiment as a pipe formed element and extends from the junction 22 to an outlet point 26 within the tank volume 2, wherein the pipe element passes through the tank shell 4 at a breakthrough point 28.

At the discharge point 26, a spray nozzle 30 closes off the BOG-LNG guide 24, wherein the discharge point 26 is arranged above the LNG filling level 8.

Below the LNG filling level 8, a discharge pump 32 for conveying liquid LNG 10 through a discharge guide 34 to an interface of an LNG consumer network 36 is provided.

The liquefied gas tank 1 according to this embodiment can thus be loaded from an external source, not shown, of LNG and / or BOG, for example an LNG carrier, and independently discharged in the direction of an LNG consumer network 36 again.

The inventive merging of a BOG flow in the BOG guide 14 and an LNG flow in the LNG guide 16 at the junction 22, the gaseous BOG can be condensed before entering the tank volume 2 of the liquid gas tank 1 in the already liquid LNG ,

For the necessary pressure in this embodiment, the compressor 18; However, it would also be conceivable that the BOG from the external source is already provided with sufficiently high pressure. The supplied LNG is subcooled with respect to the prevailing conditions and can thus liquefy the impressed BOG.

Due to the early merger already at the junction 22, the length of the total required pipe elements can be significantly reduced; In addition, only one breakthrough point 28 through the tank shell 4 is necessary, instead of at least two such breakthroughs with separate leadership. This simplifies the production of the LPG tank 1 as compared with a conventional design.

By spraying the BOG-LNG mixture by means of the spray nozzle 30 into the BOG 12 already present in the tank volume 30, additionally gaseous BOG 12 is liquefied and thus - in relative terms - the pressure in the tank volume 2 is reduced. - -

FIG. 2 shows a liquefied gas tank 1, in which the invention is applied to a circulating circuit 38.

The LPG tank 1 of this embodiment has a guide pump 120 for feeding LNG into the LNG guide 116. In addition, the liquefied gas tank 1 has a BOG guide 114, in which a guide compressor 118 is arranged. The LNG guide 116 and the BOG guide 114 converge in the junction 22 and terminate in the common BOG LNG guide 24.

In order to allow filling of the liquefied gas tank 1 with BOG or LNG (filling arrangement 103), a BOG charging line 40 is provided, which opens above the LNG filling level within the tank volume 2, and an LNG loading line 42, which below the tank LNG filling level opens.

In order to allow emptying of the liquid gas tank, branches off from the LNG guide 16 1 a discharge line 44, which can be connected via a standard interface with an LNG consumption network 36. At the separation point 46 can be connected via a suitably switchable, not shown valve, whether the LNG is directed in the direction of the junction 22 and / or in the direction of the consumer network 36.

In the liquefied gas tank 1 according to this embodiment, the amount of gaseous BOG present 12 can be reduced by means of the circulation circuit 38 independently of loading and / or unloading operations, and thus the pressure in the tank volume 2 can be reduced.

For this purpose, by means of the guide 1 14 and the associated compressor 118, gaseous BOG 12 is sucked out of the upper part of the tank volume (above the LNG filling level) and liquefied into the undercooled LNG conveyed by the pump 120 into the guide 116. This is done in the common guide 24 from the junction 22nd

By the subsequent spraying (spray nozzle 30 not shown here), a portion of the non-aspirated BOG 12 is additionally liquefied in the tank volume, which additionally reduces the pressure in the tank volume 2. This process can be carried out as long as the liquid LNG 10, which is indeed heated by feeding the relatively warmer gaseous BOG 12, is still undercooled, based on the pressure conditions prevailing in the tank. Cooling by externally supplied, relatively cold LNG is therefore necessary only at a much later date. - -

FIG. 3 shows a liquefied gas tank 1, in which the BOG guide and the LNG guide of the circulation circuit 38 are arranged completely inside the tank shell 4. This liquefied gas tank also has a filling arrangement 103 and an interface to an LNG consumer network 36 that is designed analogously to FIG.

To form the circulation circuit 38, an LNG guide 216 and a rudimentary BOG guide 214 are formed inside the tank envelope 4. The two guides 216 and 214 both open into a Venturi nozzle 48, which is arranged above the LNG filling level 8. The junction 222 is located at the entrances of the venturi 48; the orifice 26 on the common BOG-LNG guide 224 extending from the downstream end of the venturi 48.

The circulation circuit 38 is thus designed so that no breakthrough of the tank shell 4 is necessary and also requires only relatively short pipe elements.

For pressure regulation, in this embodiment liquid LNG 10 is conveyed by means of the pump 120 to the Venturi nozzle 48, which can entrain in the nozzle 48 gaseous BOG 12, which is under the pressure of the tank volume 2. A very short BOG guide 214 is shown in the illustration of FIG. 3, but it could also be omitted as long as the venturi 48 has a suitable inlet.

FIG. 4 shows a liquid gas tank 1, in which substantially the filling arrangement 3 from FIG. 1 and the circulation circuit 38 from FIG. 2 are combined with one another, so that in the embodiment described here an integrated line arrangement with a circulation circuit 338 and a filling arrangement 303 is formed.

Notwithstanding the embodiments according to FIGS. 1 and 2, in the illustration in FIG. 4 the BOG-LNG mixture below the LNG filling level 8 is pressed into the liquid LNG 10 at the end of the common BOG-LNG guide. By virtue of this design, for example, the spray nozzle 30 according to FIG. 1 can be saved if the additional liquefaction capacity realized as a result is not required.

FIG. 5 shows a liquefied gas tank 1, to which a dockable transport tank 50 (for example an LNG carrier) and customer networks (LNG customer network 36 and BOG customer network 52) are connected or connectable. - -

Apart from the deviations described below, the embodiment of the liquefied gas tank 1 shown in FIG. 5 is essentially the same as in FIG. 4, except that the connected "external source" communicates with the transport tank 50 (with its BOG connecting line 51 (functionally corresponds at least partially to the transport tank 1) 1) and its LNG connection line 53 (corresponds functionally at least partially to the LNG guide 16 in FIG. 1) .The BOG connection line 51 is connected to the BOG guide 114 by means of a BOG fluid interface 15 5, the LNG connection line 53 is connected by means of an LNG fluid interface 17 to the LNG guide 16 according to FIG.

In addition, the embodiment according to FIG. 5 differs from that according to FIG. 4 in the possibility of feeding BOG (both from the tank volume 2 and from the transport tank 50) into a BOG consumer network 52 via a valve (not shown) and a discharge line 58. Unlike in FIG. 4, the BOG-LNG mixture is sprayed in above the LNG fill level 8.

The embodiment shown in FIG. 6 differs from that according to FIG. 5 only in that the BOG-LNG mixture is pressed in below the LNG filling level 8, as in FIG.

In Figure 7, a liquefied gas tank 1 is shown, on which in addition to a dockable transport tank 50 and customer networks 36 and 52, a fixed storage tank 60 is connected.

The storage tank 60 has essentially only interfaces with the liquefied gas tank 1 with respect to BOG and with respect to LNG. Below the LNG filling level (both tanks), both an LNG pump 54 for supplying LNG from the liquid gas tank 1 to the storage tank 60 and an LNG pump 56 for supplying LNG from the storage tank 60 to the liquid gas tank 1 are provided. Above the LNG fill level, there is provided both a BOG compressor 62 for conveying BOG from the liquefied gas tank 1 into the storage tank 60 and a BOG compressor 64 for feeding BOG from the storage tank 60 into the liquefied gas tank 1. The storage tank 60 is thus, as it were, downstream of the liquefied gas tank 1 as volume and / or refrigeration capacity extension.

The storage tank 60 can be used, for example, as a storage for highly supercooled LNG by being filled with it when it is just in bulk - for example, by an incoming ship's cargo. If then in a later If, for example, a large amount of relatively warm BOG has to be taken over from another transport tank 50 of an LNG carrier, this can be recondensed in the liquefied gas tank 1 for a long time because cold LNG can be fed from the storage tank 60.

Also, regardless of the need to take warm BOGs from a transport tank 50, the storage tank 60 can serve for longer term stabilization of the LNG supercooling in liquefied gas tank 1 by pumping warmer LNG from liquefied gas tank 1 into storage tank 60 and mixing it with the relatively cold LNG and later or at the same time colder LNG is pumped from the storage tank into the liquefied gas tank 1.

The embodiments of liquefied gas tanks 1 according to the invention shown in FIGS. 5, 6 and 7 illustrate the typical case of a Regas barge (which here houses the liquefied gas tank 1 in the sense of the invention) serving as a buffer for BOG 12 and / or LNG 10 after delivery by an LNG carrier (here with transport tank 50) and before feeding into consumer networks 36 and / or 52 serves. By using a liquefied gas tank 1 according to the invention, the duration of the externally unaffected between storage in the Regas barge can be significantly extended with a very simple design.

Claims

claims

1. A method for operating a liquid gas tank (1) with a tank volume (2) for

Incorporation of LNG (10) and boil-off gas (BOG) (12), wherein a gaseous BOG stream and a liquid LNG stream are supplied to the tank volume,

characterized in that

- the BOG stream is introduced into the LNG stream, and

- Then the resulting BOG-LNG mixture is introduced into the tank volume.

2. The method according to claim 1, wherein at least part of the BOG for the BOG stream and / or at least part of the LNG for the LNG stream is supplied to the liquefied gas tank from outside the tank volume, in particular from at least one connected store (50). a Floating Storage Unit (FSU) or an LNG carrier or a Regas barge.

The method of claim 1 or 2, wherein at least a portion of the BOG for the BOG stream and / or at least a portion of the LNG for the LNG stream is withdrawn from the tank volume.

4. The method according to claim 1 and 2, wherein the BOG flow BOG from the tank volume and at least one connected memory (50) is supplied, and / or wherein the LNG stream LNG from the tank volume and at least one connected memory (50 ) is supplied.

5. The method according to any one of the preceding claims, wherein the BOG-LNG mixture

above an LNG filling level (8) of the tank volume in gaseous BOG (12) introduced, in particular sprayed is.

6. The method according to any one of claims 1 to 4, wherein the BOG-LNG mixture is introduced below a LNG filling level of the tank volume in liquid LNG (10).

7. liquefied gas tank (1) with a tank volume (2) for receiving LNG (10) and boil-off gas (BOG) (10), comprising

a BOG guide (14, 114, 214) for guiding gaseous BOG,

an LNG guide (16, 16, 216) for guiding liquid LNG,

characterized in that

the BOG guide and the LNG guide open into a common BOG-LNG guide (24, 224, 324), which is designed to guide BOG-LNG mixture and which opens into the tank volume.

8. liquefied gas tank according to claim 7, wherein the BOG guide and / or the LNG guide, in particular at its end remote tank volume, a fluid interface (15, 17) to at least one connectable memory (50), in particular a floating storage unit (FSU) or an LNG carrier or a Regas barge, and is adapted to supply the tank volume BOG or LNG from a connected memory.

Liquefied gas tank according to claim 7 or 8, wherein the BOG guide is set up,

above an LNG filling level (8) remove gaseous BOG from the tank volume and / or wherein the LNG guide is arranged to remove liquid LNG from the tank volume below an LNG filling level.

10. liquefied gas tank according to one of claims 7 to 9, wherein the mouth (26, 326) of the common BOG-LNG guide is arranged in the tank volume above a, in particular predetermined, LNG filling level of the tank volume.

1 1. Liquefied gas tank according to claim 10, wherein the mouth of a spray nozzle (30) for

Spraying the BOG-LNG mixture has.

12. Liquefied gas tank according to one of claims 7 to 9, wherein the mouth of the

common BOG-LNG guide is arranged in the tank volume below a, in particular predetermined, LNG filling level of the tank volume.

13. LPG tank according to one of claims 7 to 12, wherein the LNG guide a

Interface to a consumer network (36) which is adapted to feed LNG from the tank volume in the consumer network.

14. Liquefied gas tank according to one of claims 7 to 13, wherein the BOG guide a

Interface to a consumer network (52), which is set up to feed BOG from the tank volume in the consumer network.

15. Floating storage unit (FSU) or LNG carrier or Regas-Barge or LNG-powered vehicle or LNG-operated power plant with at least one liquefied gas tank (1) according to one of claims 7 to 14.