The present invention relates to the storage and/or transportation of liquefied natural gas (LNG).

The conventional approach to distributing LNG from a tanker to a power station involves delivering LNG from the tanker to a large capacity onshore storage tank. The LNG is regasified and then transported to the power station in gas form using a pipeline.

The installation of such apparatus is prohibitively costly and time-consuming. Accordingly, there is a need for a more flexible system that can be set up faster and at lower costs.

There is therefore provided a system and method as defined by the claims.

For a better understanding of the invention and to show how the same may be put into effect, reference is now made, by way of example only, to the accompanying drawings in which:

Figure 1 shows a schematic representation of a preferred embodiment of the invention; and

Figure 2 shows a schematic representation of an alternative generator system.

As can be seen from Figure 1 , a preferred embodiment of a storage system 1 for storing LNG comprises: a floating storage unit 10; a plurality of onshore storage units 20; one or more first cryogenic hoses 15; a plurality of portable tanks 100; and a plurality of land vehicles 150.

Also shown in Figure 1 is a generator system 2 for generating electricity comprising a turbine generator 200 that is located remotely from the storage system 1 .

The storage system 1 would be located near a shore (within 1 mile). The generator system 2 may be at least 1 mile away from the storage system 1 .

The plurality of onshore storage units 20 may be interconnected to act as a single contiguous store of LNG. The floating storage unit 10 has a larger capacity for storing LNG than any one of the plurality of onshore storage units 20, and preferably larger than the combined capacity of the onshore storage units 20.

A cryogenic hose is a hose suitable for carrying cryogenic liquid (i.e., without significant deterioration caused by the low temperature).

The floating storage unit 10 is configured to receive LNG from an LNG tanker. For example, one or more second cryogenic hoses (not shown) may be provided to connect the floating storage unit 10 with an LNG tanker. The second hoses will have internal diameters that are greater diameter than the internal diameters of the first hoses 15.

In preferred embodiments, the internal diameter of each first cryogenic hose 15 is in the range 10cm to 30cm. More preferably, the internal diameter of each first cryogenic hose 15 is in the range 15cm to 25cm. Most preferably, the internal diameter of each first cryogenic hose 15 of about 20.32cm.

The system of any claim 24, wherein the internal diameter of each further cryogenic hose for carrying LNG from an LNG tanker to the floating storage unit 10 is in the range 15cm to 45cm, preferably 25cm to 40cm, most preferably about 30.48cm.

The capacity of the floating storage unit 10 is preferably in the range 50,000 m ³ to 200,000 m ³ . In some embodiments the capacity of the floating storage unit 10 is preferably 100,000 m ³ to 150,000 m ³ . Most preferably, the capacity of the floating storage unit 10 is around 120,000 m ³ .

The capacity of each of the onshore storage units 20 is preferably in the range 50 m ³ to 1000 m ³ . In some embodiments the capacity of the onshore storage units 20 is preferably 50 m ³ to 150 m ³ . Most preferably, the capacity of the onshore storage units 20 is 100 m ³ .

The provision of multiple onshore storage units 20 is beneficial, since these can be manufactured in a different location and then individually transported to the location of the storage system 1 rather than a single large unit being manufactured in place. There are preferably at least 5 onshore storage units 20. More preferably, there are at least 10 onshore storage units. The one or more first cryogenic hoses 15 are connected between the floating storage unit 10 and the onshore storage units 20. For example, first transfer pipelines may extend from the floating storage unit 10 and second transfer pipelines may extend from the onshore storage units 20, with the one or more first cryogenic hoses 15 connected between the first and second transfer pipelines. The first hoses 15 are arranged to transfer LNG from the floating storage unit 10 to one of more of the plurality of onshore storage units 20. Preferably, pumps are provided (either on the floating storage unit 10 or onshore with the onshore storage units 20).

In addition to their connection with the floating storage unit 10, the onshore storage units 20 are configured for engagement with the portable tanks 100.

In this way, the onshore storage units 20 can supply LNG to the portable tanks 100. The portable tanks 100 may be separate from the land vehicles 150 or may form part of the land vehicles 150. When separate, the portable tanks 100 are removable from the land vehicles 150 and can be free-standing. The plurality of land vehicles 150 may be automobiles, lorries, trailer trucks, and/or trains.

The capacity of each of the portable tanks 100 is preferably in the range 10 m ³ to 100 m ³ . More preferably, the capacity of each of the portable tanks 100 is in the range 20 m ³ to 60 m ³ . Most preferably, the capacity of each of the portable tanks 100 is around 42 m ³ .

A loading bay 30 is preferably provided for the land vehicles 150 to carry the portable tanks 100 to the onshore storage units 20. The loading bay is a generally flat area providing space for the land vehicles 150 to park while the portable tanks 100 carried thereby are filled with LNG. The loading bay may hold a number of third cryogenic hoses 35 connected to the onshore storage units 20 for attachment to the portable tanks 100.

The third cryogenic hoses 35 may be connected to each of the onshore storage units 20 via a header 38, which is connected to each of the onshore storage units 20. At least one onshore pump 25 may be provided for pumping LNG from the onshore storage units 20 (optionally, via the header 38) to the portable tanks 100. Preferably, three or more onshore pumps 25 are provided. It has been found that canned motor pumps are the preferred form of onshore pump 25. Preferably, the onshore pumps 25 are each arranged to produce a differential pressure in the range 5 bar to 10 bar, preferably around 7bar.

Preferably, the onshore pumps 25 are each arranged to displace a volume at a rate in the range 300m ³ /hr to 500m ³ /hr. Most preferably, the onshore pumps 25 are each arranged to displace a volume at a rate of around 400m ³ /hr.

It is preferred to use two of the onshore pumps 25 at any one time and so the onshore pumps 25 are preferably arranged to collectively displace a volume at a rate of up to 1 ,200m ³ /hr. More preferably, the onshore pumps 25 are arranged to collectively displace a volume at a rate of up to 800m ³ /hr.

As is known in the art, it is necessary to maintain the cryogenic temperature of the LNG when stored. Thus, each of the LNG storage means described herein, in that they are suitable for storing LNG, are necessarily suitable for maintaining substantially all the LNG in liquefied form. There will, however, be a small amount of unavoidable "boil off". Therefore, if desired, a boil off handling system 50, 52, 54, 56 may be provided.

The boil off handling system 50, 51 , 52, 54, 56 is provided onshore (near the onshore storage tanks 20).

The boil off handling system 50, 51 , 52, 54, 56 comprises a vent 50 supplied via a valve 51 to allow a controlled amount of boil off to escape when/if required.

Optionally, the boil off handling system 50, 51 , 52, 54, 56 also comprises: one or more compressors 52 to compress the boil off gas; an accumulator 54 to store the boil off gas compressed by the compressor(s) 52; and one or more liquefaction units 56, supplied by the accumulator 54, to recover LNG from the boil off gas. The liquefaction unit(s) 56 may supply LNG back to the onshore storage units 20 and/or the floating storage unit 10.

The generator system 2 is located remotely from the storage system 1 . In this way, the LNG may be stored in the storage system 1 at the shore, with the LNG transported as needed to the generator system 2 by the land vehicles 150. The generator system 2 can be located where there is a need for energy, such as near a town, city or an industrial centre such as a manufacturing plant or factory. In some embodiments, multiple generator systems 2 maybe distributed in and/or around the town, city or an industrial centre. In some embodiments, multiple generator systems 2 may be distributed in a plurality of locations remote from one another and remote from the storage system 1 .

Preferably, the generator system 2 comprises: the turbine generator 200; a vaporiser 210; a trim heater 215; one or more turbine pumps 220; and turbine connection means 260 for connecting the turbine pumps 220 to portable storage tanks 100. The turbine generator 200 with one or more of these components can be collectively referred to as a turbine generator assembly.

The turbine generator 200 is arranged to receive LNG from a portable tank 100 via the vaporiser 210, the trim heater 215, the one or more turbine pumps 220, and the connection means.

The turbine connection means 260 may be provided in a turbine loading bay (not shown) similar to the loading bay 30 described above. The turbine loading bay is a generally flat area providing space for the land vehicles 150 to park while LNG is decanted from the portable tanks 100 via the turbine connection means. The turbine loading bay may hold a number of cryogenic hoses, forming the turbine connection means 260, connected to the turbine pumps 220 for attachment to the portable tanks 100. Preferably, two or more turbine pumps 220 are provided.

Optionally, as shown in Figure 2, further storage 280 may be provided as part of the generator system 2. Further storage 280 may comprise one or more horizontal or vertical tanks. The one or more turbine pumps 220 can also be used to pump LNG from the further storage 280 to the turbine generator 200.

Optionally, one or more transfer pumps 285 can be provided for pumping LNG from the portable storage tanks 100 into the further storage 280.

In preferred embodiments, the one or more transfer pumps 285 are arranged to displace a volume at a rate in the range 10m ³ /hr to 30m ³ /hr. More preferably, the one or more transfer pumps 285 are arranged to displace a volume at a rate of around 20m ³ /hr. In preferred embodiments, the one or more transfer pumps 285 are arranged to produce a differential pressure in the range 5 bar to 10 bar. More preferably, the one or more transfer pumps 285 are arranged to produce a differential pressure of around 7 bar.

The capacity of the further storage 280 is preferably in the range 10 m ³ to 100 m ³ . More preferably, the capacity of each of the further storage 280 is in the range 20 m ³ to 60 m ³ . Most preferably, the capacity of each of the further storage 280 is around 40 m ³ .

In preferred embodiments, the one or more turbine pumps 220 are arranged to displace a volume at a rate in the range 10m ³ /hr to 20m ³ /hr. More preferably, the one or more turbine pumps 220 are arranged to displace a volume at a rate of around 14m ³ /hr.

In preferred embodiments, the one or more turbine pumps 220 are arranged to produce a differential pressure in the range 25 bar to 40 bar. More preferably, the one or more turbine pumps 220 are arranged to produce a differential pressure of around 36 bar.

In some embodiments, the turbine generator 200 is portable. For example, it may be carried by (or be suitable to be carried by) a land vehicle 150. Optionally, the vaporiser 210, the trim heater 215, the one or more turbine pumps 220, and the turbine connection means 260 may also be carried by (or be suitable to be carried by) the same land vehicle 150 (or by another land vehicle, or respective land vehicles).

For such a turbine generator 200, the portable storage tank 100 may provide the main form of LNG storage. In other words, the turbine generator 200 may be arranged to use the LNG pumped directly from the portable tank 100 without being stored in an intermediate storage.

However, it is preferable that the further storage 280 is provided as an emergency store of LNG.

Alternatively, the further storage 280 can be used as the main form of storage such that the turbine generator 200 is arranged to use the LNG pumped directly from the further storage 280 with further storage 280 being filled from the portable tanks 100.

Preferably, the vaporiser 210 is an ambient air vaporiser. Such a vaporiser can use the heat in the atmospheric air for vaporisation of LNG instead of burning valuable volumes of LNG cargoes (typically, two per cent of the LNG) in Submersible Combustion Vaporizers (SCV) or circulating large quantities of sea water through Open Rack Vaporisers.

Preferably, the turbine generator(s) 200 is/are arranged to generate electricity at a rate from 5MW to 50MW, preferably 30MW.

A preferred method of using the above system involves transporting LNG from an LNG tanker (not shown, by LNG tanker is meant any vessel that carries LNG by sea) to a turbine generator 200. This would preferably include the following steps.

The LNG tanker is engaged with the floating storage unit 10 via the second cryogenic hoses.

LNG is transferred via the second cryogenic hoses from the LNG tanker to the floating storage unit 10.

LNG is then transferred from the floating storage unit 10 to the plurality of onshore storage units 20 via the one or more first cryogenic hoses 15.

A portable tank 100 is engaged with the plurality of onshore storage units 20.

LNG is transferred from the onshore storage units 20 to the portable tank 100.

One of the land vehicles 150 carries the portable tank 100 to a remote location where a turbine generator 200 is located.

The turbine generator 200 is supplied with LNG from the portable tank 100 and thereby generates electricity.

Preferably, a plurality of portable tanks 100 can be filled from the plurality of onshore storage units 20.

The portable tanks 100 can be carried to a plurality of remote locations using separate land vehicles 150.

The turbine generator 200 at each of the remote locations is supplied with LNG from the corresponding portable tank 100 and thereby generates electricity. Alternatively, at each of the remote locations the portable tank 100 supplies LNG to the corresponding further storage 280, and the turbine generator 200 is supplied with LNG from the further storage 280 and thereby generates electricity.

Advantageously, instead of the slow process of building a monolithic structure for storing a large quantity of LNG in situ at a fixed location at huge cost, the above storage system 1 can be manufactured in parts and the individual parts separately transported and simply interconnected at the chosen location. Such an LNG storage system may be manufactured by a method that includes the following steps.

Towing a floating storage unit 10 for storing LNG to a desired mooring location.

Manufacturing a plurality of onshore storage units 20 for storing LNG.

Transporting the plurality of onshore storage units 20 to a location onshore near the mooring location.

The onshore storage units 20 may be transported (for example, individually) using land vehicles 150.

Connecting one or more cryogenic hoses 15 between the plurality of onshore storage units 20 and the floating storage unit 10.

A suitable turbine generator is the GE TM2500 30MW gas turbine, which can be mounted on a trailer.

Suitable onshore storage units are those provided by Chart Ferox/G of A

Suitable cryogenic hoses and vaporisers can be obtained from Cryonorm or KLAW LNG.