EP3314159A1

EP3314159A1 - Regasification terminal and a method of operating such a regasification terminal

Info

Publication number: EP3314159A1
Application number: EP16733435.8A
Authority: EP
Inventors: Marcel Filip Dabkowski; Mees Hidde VAN DEN BERG
Original assignee: Shell Internationale Research Maatschappij BV
Current assignee: Shell Internationale Research Maatschappij BV
Priority date: 2015-06-29
Filing date: 2016-06-27
Publication date: 2018-05-02
Anticipated expiration: 2036-06-27
Also published as: PH12017502400A1; JP2018520318A; KR102541670B1; MA42241A; KR20180021787A; JP6827964B2; CN107810361B; SG10201911907RA; WO2017001313A1; EP3314159B1; CN107810361A

Abstract

The invention relates to a method of operating a regasification terminal, comprising: a) obtaining a re-gas stream (10) of LNG from one or more LNG storage tanks (1), b) passing the re-gas stream (10) through a regasifier unit (20), c) receiving a feed stream (40) of pressurized LNG, d) generating a cooling stream (11) comprising at least a portion of the re-gas stream (10), e) processing the feed stream (40) of pressurized LNG at the second pressure into a processed feed stream (43) comprising LNG by expanding the feed stream (40) and cooling the feed stream (40) against the cooling stream (11), f) passing the processed feed stream (43) to at least one of the LNG storage tanks (1).

Description

Regasification terminal and

a method of operating such a regasification terminal

The present invention relates to a regasification terminal and a method of operating a regasification terminal.

Natural gas is a useful fuel source. However, it is often produced a relative large distance away from market. In such cases it may be desirable to liquefy natural gas in an LNG plant at or near the source of a natural gas stream. In the form of LNG natural gas can be stored and transported over long distances more readily than in gaseous form, because it occupies a smaller volume.

The LNG is transported by a suitable LNG carrier vessel to a regasification terminal (also referred to as

revaporizing terminal or import terminal) , where it is revaporized before being fed to the gas grid. In a

regasification terminal the cold present in the LNG is typically transferred to the ambient via cooling air or cooling water .

In order to revaporize the LNG heat may be added to the

LNG. Before adding the heat, the LNG is often pressurized to meet the requirements of the gas grid. Typically, the gas grid is at a pressure of above 60 bar, e.g. 80 bar. The revaporized natural gas product may then be sold to a customer, suitably via the gas grid.

Regasification terminals and methods to regasify LNG are known in the art and are for instance described in patent application publication US2010/0000233, US2006/0242969

WO2008012286, WO2013186271, WO2013186277 and WO2013186275 describe an apparatus and method for heating a liquefied stream. These documents focus in particular on heat

exchangers to transfer heat from the ambient to the liquefied stream by cycling a heat transfer fluid through a circuit from a first heat transfer zone to a second heat transfer zone .

LNG may be produced, transported and stored at different pressures and associated temperatures. It will be understood that the exact combination of pressure and temperature at which natural gas liquefies (the boiling point), depends on the exact composition of the natural gas.

Atmospheric LNG is produced at a pressure close to atmospheric pressure, consequently at a temperature close to -162°C. Atmospheric LNG requires a relatively high cooling effort, but has the advantage that the LNG can be transported and stored under atmospheric pressure, minimizing the safety risks and reducing the costs of the storage tanks used for transportation and storage.

Pressurized LNG (also referred to as cryo compressed LNG

(ccLNG) ) is produced at a pressure greater than atmospheric pressure and at a temperature equal to the boiling point of the natural gas, the exact value depending on the composition of the natural gas. The pressure of pressurized LNG may be above 2 bar or at least above 5 bar. For instance,

pressurized LNG may be produced at a pressure of 15 - 17 bar at a temperature of approximately -115°C. Pressurized LNG has the advantage that less cooling effort is required making production less energy-consuming.

EP2442056 describes a method for producing pressurized liquefied natural gas (PLNG) and a production system

therefor .

However, transportation and storage of pressurized LNG requires additional safety measures and relatively more expensive and difficult to manufacture storage tanks

(pressurized containers), as the tanks should be reinforced to withstand the elevated pressure. CA2550469 provides an example of a fiber reinforced plastic pressure vessel for retaining pressurized and liquefied natural gas.

It is an object to provide an improved integration of pressurized LNG with the regasification terminal, which reduces at least some of the safety risks associated with the pressurized LNG value chain.

The present invention provides a method of operating a regasification terminal, the method comprising:

a) obtaining a re-gas stream of LNG from one or more LNG

storage tanks, the one or more storage tanks being at a first pressure,

b) passing the re-gas stream through a regasifier unit to obtain a regasified natural gas stream,

wherein the method further comprises

c) receiving a feed stream of pressurized LNG at a second pressure, the second pressure being greater than the first pressure,

d) generating a cooling stream comprising at least a portion of the re-gas stream,

e) processing the feed stream of pressurized LNG at the

second pressure into a processed feed stream comprising LNG by

el) expanding the feed stream, and

e2) cooling the feed stream against the cooling stream, f) passing the processed feed stream to at least one of the LNG storage tanks.

The cooling stream may comprise the complete re-gas stream or a portion thereof, i.e. a side-stream thereof.

El) and e2) may be performed in any suitable order, including simultaneously. El) and/or e2) may also be

performed in one or more stages, wherein the different stages can be performed in any suitable order. For instance, the feed stream can be expanded, cooled against the cooling stream and subsequently further expanded.

El) preferably comprises expansion-cooling whereby a temperature drop is obtained by expanding, for instance by passing the feed stream through a throttle valve or expander.

Expansion-cooling can take place in a single or a plurality of JT valves or expanders.

Cooling according to e2) can take place in one or a plurality of (parallel/ serial ) heat exchangers.

Expanding comprises reducing the pressure from the second pressure to a lower pressure, typically to the first pressure or to a pressure above the first pressure leaving sufficient overpressure to transport the processed stream to one of the

LNG storage tanks. So, the processed feed stream of LNG typically has a pressure (substantially) equal to the first pressure .

Preferably, the pressurized LNG meets the specifications of (atmospheric) LNG in terms of composition.

Preferably, the feed stream of pressurized LNG comprises less than 250ppm C02, more preferably less than 150 ppm C02 and even more preferably less than 50 ppm C02 (ppm = parts per million) .

According to a further aspect there is provided a

regasification terminal for regasifying LNG, comprising - one or more LNG storage tanks, the one or more storage tanks being at a first pressure,

- a regasifier unit comprising an inlet which is in fluid communication with the one or more LNG storage tanks to receive a re-gas stream of LNG and an outlet for discharging a regasified natural gas stream,

- a processing unit comprising a pressurized LNG inlet for receiving a feed stream of pressurized LNG at a second pressure, the second pressure being greater than the first pressure, the processing unit comprising an expansion device and a heat exchanging unit for processing the feed stream into a processed stream, wherein the processing unit

comprises an outlet which is in fluid communication with one or more LNG storage tanks, wherein the heat exchanging unit comprises an inlet for receiving a cooling stream to cool the feed stream, the cooling comprising at least a portion of the re-gas stream.

The invention will be further illustrated hereinafter, using examples and with reference to the drawing in which;

Fig. 1 schematically shows a first embodiment,

Fig.'s 2 and 3 schematically show alternative

embodiments .

In these figures, same reference numbers will be used to refer to same or similar parts. Furthermore, a single reference number will be used to identify a conduit or line as well as the stream conveyed by that line.

It is presently proposed to provide a method and

regasification terminal in which a feed stream of pressurized LNG from a pressurized LNG carrier is received at an

atmospheric regasification terminal, which is designed and built to store LNG to be regasified at or close to

atmospheric pressure.

The regasification terminal for regasifying LNG comprises - one or more LNG storage tanks (1), the one or more storage tanks (1) being at a first pressure,

- a regasifier unit (20) comprising an inlet which is in fluid communication with the one or more LNG storage tanks to receive a re-gas stream (10) of LNG and an outlet for discharging a regasified natural gas stream (30),

- a processing unit (5) comprising a pressurized LNG inlet (6) for receiving a feed stream (40) of pressurized LNG at a second pressure, the second pressure being greater than the first pressure, the processing unit (5) comprising an expansion device (41) and a heat exchanging unit (50) for processing the feed stream (40) into a processed stream (43), wherein the processing unit (5) comprises an outlet (7) which is in fluid communication with one or more LNG storage tanks (1), wherein the heat exchanging unit (50) comprises an inlet for receiving a cooling stream (11) to cool the feed stream (40), the cooling comprising at least a portion of the re-gas stream (10) .

The cold energy that is released during regasification at the regasification terminal is not wasted, but at least partially used to cool the pressurized LNG into atmospheric LNG which can be stored in the LNG storage tanks present at the atmospheric regasification terminal. By using the cold energy from the regasification process effectively, a thermodynamically balanced process and potentially a higher regasification rate can be obtained.

The term pressurized LNG (or ccLNG) is used to refer to liquid natural gas which is kept at elevated pressures, meaning a pressure greater than 2 bar, preferably greater than 10 bar and more preferably greater than 12 bar.

According to an example, pressurized LNG can be at a pressure in the range of 15 - 17 bar. The temperature of the

pressurized LNG is at the boiling temperature for the given pressure, which depends on the composition of the natural gas .

The term atmospheric LNG is used to refer to liquid natural gas which is kept close to, preferably slightly above, atmospheric or ambient pressure. The first pressure is typically in the range of 0.9 - 1.3 bar or 1.0 - 1.3 bar. The first pressure in the storage tanks 1 may be in the range of 50 - 200 mbarg or 100 - 200 mbarg. The term bar is used in this text is used to refer to absolute pressure, where the term barg is used to refer to bar gauge (zero-referenced against the atmospheric pressure) .

It will be understood that the pressure of the

atmospheric LNG may be increased when being pumped.

The feed stream of pressurized LNG is transformed to atmospheric LNG and subsequently stored in an LNG storage tank. The LNG storage tank can be a storage tank that is suitable for storing atmospheric LNG and does not need to be designed to withstand higher pressures. The regasification terminal is thus able to receive and process pressurized LNG without the need of pressurized LNG storage tanks.

A regas-stream of LNG is taken from the LNG storage tank and passed to a regasifier unit to produce natural gas at a pressure suitable to feed the regasified natural gas to the gas grid.

The feed stream of pressurized LNG is transformed to atmospheric LNG in an energy efficient manner by allowing the feed stream of pressurized LNG to exchange heat with the regas-stream in a heat exchanger and expanding the feed stream of pressurized LNG to atmospheric pressure, thereby achieving a cooling effect.

During times when no feed stream of pressurized LNG is present, e.g. when no pressurized LNG carrier is moored at the regasification terminal and busy off-loading pressurized LNG, the regas-stream of LNG from the LNG storage tank may be regasified in any suitable regasifier unit, for instance as described in any of the following patent documents:

WO2008012286, WO2013186271, WO2013186277 and WO2013186275.

When a pressurized LNG carrier is present and busy off^¬ loading, the regas-stream of LNG from the storage tank, or a side-stream thereof, may be re-directed through a heat- exchanger in which it is warmed against the feed stream of pressurized LNG, thereby obtaining a warmed re-gas stream, which is passed to the regasifier unit. The warmed re-gas stream may be fed to the regasifier unit at an intermediate point, as less heat is needed to regasify the warmed stream.

The feed stream of pressurized LNG is fed to the heat exchanger to be cooled against the (side-stream of the) re- gas stream and expanded to atmospheric pressure to obtain the processed feed stream comprising LNG. The processed feed stream may be passed directly to the (atmospheric) LNG storage tank or may be passed to a gas-liquid separator to obtain a liquid stream which is passed to the LNG storage tank and a gaseous stream which is passed to the LNG storage tank via a re-liquefying unit .

Expansion can take place upstream or downstream of the heat exchanger.

The proposed method and regas terminal have the advantage that there is no need for additional safety measures or reinforced hardware to process and store pressurized LNG, other than the piping up to the point where the pressure of the pressurized LNG is reduced to the first pressure. Re-gas terminals can now receive pressurized LNG in an efficient and safe way, while at the same time being suitable to receive atmospheric LNG. Existing re-gas terminals having atmospheric LNG storage tanks can be integrated with the pressurized LNG value chain with minimal additional equipment and change of plant design. Existing re-gas terminals suitable for

processing atmospheric LNG can be modified with minimal hardware investments to also be suitable to receive

pressurized LNG.

According to an embodiment the first pressure is in the range of 0.9 - 1.2 bar, such as ambient or atmospheric pressure and the second pressure is above 2 bar, preferably above 5 bar, and more preferably above 12 bar. The second pressure may for instance be in the range of 15 - 17 bar.

The re-gas stream has a temperature equal to the boiling point of the LNG at the first pressure.

The feed stream of pressurized LNG has a temperature equal to the boiling point of the pressurized LNG at the second pressure.

Embodiments will now be described in more detail with reference to Fig.'s 1 - 3.

Fig. 1 schematically shows a regasification terminal. The regasification terminal comprises a storage tank 1 at a first comprising LNG. A re-gas stream 10 is obtained by using a suitable pump 2. The re-gas stream 10 will therefore have a pressure above the first pressure.

The LNG storage tank 1 is in fluid connection with a regasifier unit 20 via a re-gas stream conduit. The

regasifier unit 20 is arranged to receive the re-gas stream and generate and discharge a regasified natural gas stream 30 and pass the regasified natural gas stream to the gas grid, schematically indicated with reference 31.

According to an embodiment b) comprises:

bl) pressurizing the re-gas stream 10 to a third pressure to obtain a pressurized re-gas stream 13,

b2) warming at least part of the pressurized re-gas stream 13 against an ambient stream 22 in a re-gasifier heat exchanger 21.

Fig. 1 schematically shows a compressor 12 having an inlet arranged to receive the re-gas stream 10 and an outlet to discharge the pressurized re-gas stream 13. The outlet 13 of the compressor 12 is in fluid communication with an inlet of one (or more) re-gasifier heat exchanger 21. The regasifier heat exchanger comprises a first flow path between the inlet of the re-gasifier heat exchanger 21 and an outlet of the re-gasifier heat exchanger 21 and a second flow path between an ambient inlet and an ambient outlet, such that the first and second flow paths can exchange heat.

The ambient stream may be a stream comprising ambient air or a stream comprising water, such as sea water.

Bl) is preferably performed before b2), as warming against an ambient stream can be done more effectively at a higher pressure.

The third pressure is preferably equal to a required output pressure of the regasified natural gas stream 30, such as a gas grid pressure, typically above 60 bar, e.g. 80 bar.

The outlet of the re-gasifier heat exchanger 21 is in fluid communication with the gas grid 31.

Fig. 1 further shows a carrier vessel 60 comprising one or more pressurized LNG storage tanks 61 arranged to comprise pressurized LNG. The carrier vessel 60 is not part of the regasification terminal .

The feed stream of pressurized LNG comprises less than 250ppm C0₂, more preferably less than 150 ppm C0₂ and even more preferably less than 50 ppm C0₂ (ppm = parts per

million) .

The regasification terminal comprises a processing unit 5 comprising a pressurized LNG inlet 6 for receiving a feed stream 40 of pressurized LNG at a second pressure, the second pressure being greater than the first pressure, i.e. the pressure in the storage tank 1.

The regasification terminal is arranged to receive the feed stream 40 of pressurized LNG at a second pressure from the carrier vessel 60. The processing unit (5) comprises an expansion device (41) and a heat exchanging unit (50) for processing the feed stream (40) into a processed stream (43) .

The expansion device 41, such as an expander (shown) or throttle valve (not shown) is arranged to receive the feed stream of pressurized LNG via a pressurized feed conduit 40. The expander 41 has an inlet arranged to receive the feed stream of pressurized LNG at the second pressure and an outlet is arranged to discharge an expanded feed stream 42 and is in fluid communication with an inlet of the heat exchanging unit 50.

The heat exchanging unit 50 may comprise one or more (serial/parallel) heat exchangers. The heat exchanging unit 50 comprises an outlet for discharging a processed feed stream 43, which has a lower pressure than the second pressure and has a lower temperature than the temperature of the feed stream 40 of pressurized LNG. The outlet of the heat exchanging unit 50 is in fluid communication with the LNG storage tanks 1.

In d) a cooling stream 11 is obtained comprising at least a portion of the re-gas stream 10. The cooling stream 11 obtained preferably comprises at least a portion of the pressurized re-gas stream 13 as will be explained in more detail below.

The cooling stream 11 and the feed stream 40 of

pressurized LNG or expanded feed stream 42 are allowed to exchange heat in the heat exchanging unit 50. As the cooling stream 11 will typically have a lower temperature than the feed stream 40 of pressurized LNG or expanded feed stream 42, the cooling stream 11 will be warmed and the feed stream 40 of pressurized LNG or expanded feed stream 42 will be cooled.

According to an embodiment e2) comprises obtaining a warmed cooling stream 14 and passing the warmed cooling stream 14 to the regasifier unit 20.

The warmed cooling stream 14 is obtained at the outlet of the heat exchanging unit 50.

As the warmed cooling stream 14 is warm with respect to the (pressurized) re-gas stream, the warming duty of the regasifier unit can be reduced while maintaining a similar output rate or the output rate of the regasifier unit can be increased with a similar warming duty.

According to an embodiment the warmed cooling stream 14 is introduced in the re-gasifier heat exchanger 21 at an intermediate position.

As the warmed cooling stream is relatively warm, it does not need to pass through the entire regasifier heat

exchanger. The re-gasifier heat exchanger 21 comprises an inlet for the pressurized re-gas stream 13' and an outlet for the regasified natural gas stream 30 and an intermediate inlet 23 for receiving the warmed cooling stream 14.

According to an embodiment, the re-gasifier heat

exchanger 21 comprises two or more re-gasifier sub-heat exchangers placed in series, wherein the intermediate inlet 23 is positioned in between two adjacent sub heat exchangers.

Alternatively, the re-gasifier heat exchanger 21

comprises an inlet 23' for the (pressurized) re-gas stream 10/13 and the warmed cooling stream 14 is passed to the inlet of the re-gasifier heat exchanger 21. In such an embodiment, the warming duty of the re-gasifier heat exchanger 21 may be lowered or the throughput may be increased, or a combination of both.

According to an embodiment the cooling stream 11 is generated by splitting the re-gas stream 10 in a side-stream of the re-gas stream 13'', in particular a side-stream of the pressurized re-gas stream (13) as obtained in b2), and a remainder of the re-gas stream 13', in particular a remainder of the pressurized re-gas stream 13.

The side-stream 13'' may be obtained by splitting off a portion of the (pressurized) re-gas stream 13. The portion or flow rate of the side-stream 13'' may, among other factors, depend on the flow rate of the feed stream 40 of pressurized LNG, the temperature and pressure of the feed stream 40 of pressurized LNG, the efficiency of the cooling of the feed stream 40 against the cooling stream 11 etc. The side-stream may be at least at 10% of the re-gas stream 10, at least 25% of the re-gas stream, at least 50% or at least 75% of the re- gas stream. According to an embodiment, the side-stream is more than 95% of the re-gas stream or even 100% of the re-gas stream. The method may comprise controlling the flow rate of the side-stream 13'' in response to one or more of these factors.

The side-stream is preferably obtained from in between bl) and b2) . In case only a portion of the pressurized re-gas stream 10 is split off, a remainder of the pressurized re-gas stream 13' is passed to the regasifier heat exchanger 21.

According to an embodiment the method comprises

g) re-combining the warmed cooling stream 14 with the remainder of the re-gas stream 13', in particular the remainder of the pressurized re-gas stream 13.

According to an embodiment g) takes place at an

intermediate position in a regasifier heat exchanger 21 in the regasifier unit 20.

As the warmed re-gas stream is warmer than the re-gas stream directly obtained from the LNG storage tank, less effort is needed to regasify this stream. The warmed re-gas stream can therefore be introduced in the regasifier unit at an intermediate position, for instance halfway a heat exchanger in which it is warmed against an ambient stream.

According to an embodiment schematically shown in Fig. 2, g) takes place at an upstream position of a regasifier heat exchanger 21 in the regasifier unit 20.

The upstream position includes the inlet of the

regasifier heat exchanger 21. Alternatively, the regasifier unit can be operated at a lower capacity while maintaining the same output rate.

The processed feed stream 43 may be directly passed to the at least one of the LNG storage tanks 1 as shown in Fig. 1. The term directly is used here to indicate that no further substantial processing steps are performed in between. This may be preferred when the processed feed stream comprises no gaseous fraction or a gaseous fraction below a predetermined threshold fraction.

Fig. 3 shows an alternative embodiment wherein f) comprises

fl) separating the processed feed stream 43 in a liquid stream 45 and a gaseous stream 46 in a gas-liquid separator 44,

f2) passing the liquid stream 45 to at least one of the

LNG storage tanks 1, and

f3) reliquefying the gas stream 46 in a reliquefaction unit 70 to obtain a reliquefied stream 47 and passing the reliquefied stream 47 to at least one of the LNG storage tanks 1.

This embodiment may be advantageous when the processed feed stream 43 has a relatively low liquid fraction.

The gas-liquid separator or gas-vapour separator 47 may be any suitable separator, such as a knock-out vessel or the like.

According to an embodiment the method comprises

- executing c) - f) when a feed stream 40 of pressurized LNG is available and

- interrupting c) - f) when no a feed stream 40 of pressurized LNG is available.

C)-f) can be executed when a supply of pressurized LNG at a second pressure is available and interrupted when no supply of pressurized LNG at a second pressure is available. The feed stream 40 of pressurized LNG at a second pressure may be received from a carrier vessel 60. C) - f) are only executed when a loaded carrier vessel is present and connected to the regasification terminal. In case the carrier vessel is not connected, does not comprise any pressurized LNG at the second pressure or no carrier vessel is present, c) - f) are interrupted and the regasification terminal is operated by executing a) - b) only.

So, according to an embodiment, c) - f) are optional. According to an embodiment a) comprises controlling a flow rate of the re-gas stream 10 by

- setting the flow rate of the re-gas stream 10 at a first flow rate level when c) - f) are executed and

- setting the flow rate of the re-gas stream 10 at a second flow rate level when c) - f) are interrupted, the first flow rate level being higher than the second flow rate level.

So, when a feed stream of pressurized LNG at a second pressure is being received, the amount of LNG being

regasified can be increased, as part of the warming duty is obtained from the pressurized LNG.

According to an embodiment b) comprises controlling a warming duty of the regasifier unit by

- setting the warming duty of the regasifier unit at a first level when c) - f) are executed and

- setting the warming duty of the regasifier unit at a second level when c) - f) are interrupted, the second level being lower than the first level.

The warming duty can for instance be controlled by controlling a flow rate of the ambient stream 22 in the re- gasifier heat exchanger 21.

When a feed stream of pressurized LNG at a second pressure is being received, the regasifier unit can be operated more efficiently and the warming duty can be lowered, as part of the warming duty is obtained from the pressurized LNG .

The person skilled in the art will understand that the present invention can be carried out in many various ways without departing from the scope of the appended claims.

Claims

1. Method of operating a regasification terminal, the method comprising :

a) obtaining a re-gas stream (10) of LNG from one or more LNG storage tanks (1), the one or more storage tanks (1) being at a first pressure, wherein the first pressure is in the range of 0.9 - 1.2 bar,

b) passing the re-gas stream (10) through a regasifier unit (20) to obtain a regasified natural gas stream (30), wherein the method further comprises

c) receiving a feed stream (40) of pressurized LNG at a

second pressure, the second pressure being greater than the first pressure, the second pressure being above 2 bar, d) generating a cooling stream (11) comprising at least a portion of the re-gas stream (10),

e) processing the feed stream (40) of pressurized LNG at the second pressure into a processed feed stream (43)

comprising LNG by

el) expanding the feed stream (40), and

e2) cooling the feed stream (40) against the cooling stream (11 ) ,

f) passing the processed feed stream (43) to at least one of the LNG storage tanks (1) .

2. Method according to claim 1, wherein the first pressure is in the range of 50 - 200 mbarg and the second pressure is preferably above 5 bar, and more preferably above 12 bar.

3. Method according to any one of the preceding claims, wherein b) comprises:

bl) pressurizing the re-gas stream (10) to a third pressure to obtain a pressurized re-gas stream (13), b2) warming at least part of the pressurized re-gas stream (13) against an ambient stream (22) in a re-gasifier heat exchanger (21 ) .

4. Method according to any one of the preceding claims, wherein e2) comprises obtaining a warmed cooling stream (14) and passing the warmed cooling stream (14) to the regasifier unit (20) .

5. Method according to claim 4, wherein the warmed cooling stream (14) is introduced in the re-gasifier heat exchanger (21) at an intermediate position.

6. Method according to any one of the preceding claims, wherein the cooling stream (11) is generated by splitting the re-gas stream (10) in a side-stream of the re-gas stream (13'' ), in particular a side-stream of the pressurized re-gas stream (13) as obtained in b2), and a remainder of the re-gas stream (13'), in particular a remainder of the pressurized re-gas stream (13) .

7. Method according to claims 5 and 6, wherein the method comprises

g) re-combining the warmed cooling stream (14) with the remainder of the re-gas stream (13' ) , in particular the remainder of the pressurized re-gas stream (13) .

8. Method according to claim 7, wherein g) takes place at an intermediate position in a regasifier heat exchanger (21) in the regasifier unit (20) .

9. Method according to claim 7, wherein g) takes place at an upstream position of a regasifier heat exchanger (21) in the regasifier unit (20) .

10. Method according to any one of the preceding claims, wherein f) comprises

fl) separating the processed feed stream in a liquid stream (45) and a gaseous stream (46) in a gas-liquid separator (44) ,

f2) passing the liquid stream (45) to at least one of the LNG storage tanks (1), and

f3) reliquefying the gas stream (46) in a reliquefaction unit (70) to obtain a reliquefied stream (47) and passing the reliquefied stream (47) to at least one of the LNG storage tanks (1) .

11. Method according to any one of the preceding claims, wherein the method comprises

- executing c) - f) when a feed stream (40) of pressurized LNG is available and

- interrupting c) - f) when no a feed stream (40) of

pressurized LNG is available.

12. Method according to claim 11, wherein a) comprises controlling a flow rate of the re-gas stream (10) by

- setting the flow rate of the re-gas stream (10) at a first flow rate level when c) - f) are executed and

- setting the flow rate of the re-gas stream (10) at a second flow rate level when c) - f) are interrupted, the first flow rate level being higher than the second flow rate level.

13. Method according to claim 11, wherein b) comprises controlling a warming duty of the regasifier unit by - setting the warming duty of the regasifier unit at a first level when c) - f) are executed and

14. Regasification terminal for regasifying LNG, comprising

- one or more LNG storage tanks (1), the one or more storage tanks (1) being at a first pressure, the first pressure being in the range of 0.9 - 1.2 bar, - a regasifier unit (20) comprising an inlet which is in fluid communication with the one or more LNG storage tanks to receive a re-gas stream (10) of LNG and an outlet for discharging a regasified natural gas stream ( 30 ) ,

- a processing unit (5) comprising a pressurized LNG inlet

(6) for receiving a feed stream (40) of pressurized LNG at a second pressure, the second pressure being greater than the first pressure, the second pressure being above 2 bar, the processing unit (5) comprising an expansion device (41) and a heat exchanging unit (50) for processing the feed stream (40) into a processed stream (43), wherein the processing unit (5) comprises an outlet (7) which is in fluid communication with one or more LNG storage tanks (1), wherein the heat

exchanging unit (50) comprises an inlet for receiving a cooling stream (11) to cool the feed stream (40), the cooling comprising at least a portion of the re-gas stream (10) .