Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B27/00—Arrangement of ship-based loading or unloading equipment for cargo or passengers
  • B63B27/24—Arrangement of ship-based loading or unloading equipment for cargo or passengers of pipe-lines
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B25/00—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby
  • B63B25/02—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods
  • B63B25/08—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods fluid
  • B63B25/12—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods fluid closed
  • B63B25/16—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods fluid closed heat-insulated
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B2207/00—Buoyancy or ballast means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2221/00—Handled fluid, in particular type of fluid
  • F17C2221/03—Mixtures
  • F17C2221/032—Hydrocarbons
  • F17C2221/033—Methane, e.g. natural gas, CNG, LNG, GNL, GNC, PLNG
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2265/00—Effects achieved by gas storage or gas handling
  • F17C2265/05—Regasification

Definitions

• the invention relates to a special vessel together with a system for unloading fluid from a vessel to a shore-based infrastructure.
• a system In connection with the transport of fluid such as natural gas from the field to the area in which the natural gas has to be unloaded, a system is often employed involving a number of special vessels and a series of fairly complicated operational steps.
• a known vessel which is commonly employed for this purpose is an LNG carrier, which is equipped with special tanks suitable for storing natural gas in its liquid state.
• at least one additional vessel is often employed for receiving fluid directly from the well and treating the fluid before it is transferred to the LNG carrier.
• the LNG carrier will transfer the load to an intermediate storage unit where the liquefied natural gas is converted to a gaseous state before being transferred to the end user.
• LNG low-density natural gas
• vaporizers for regasifying the liquefied natural gas.
• the carrier On arrival at the unloading point, the carrier is moored in such a manner that the vessel is located at a distance from the mooring structure by mooring lines which extend from the bow area to the mooring structure.
• the liquefied natural gas is regasified before being transported in a pipeline system which transfers the natural gas from the carrier to a shore-based installation which in the publication represents the end user.
• the technical solution according to the present invention indicates the use of a submerged buoy structure which has to be brought into abutment in a recess in the vessel's hull for transferring natural gas to shore.
• a substantially simplified solution is achieved which provides advantages both with regard to manning and the equipment situation, since mooring and fluid transfer are implemented by means of one and the same structure.
• US 5564957 discloses a vessel in which a buoy structure is provided for installation in a recess in the bow portion.
• the buoy structure is intended for use as a combined mooring and transfer structure for transport of a liquid medium to and from the vessel.
• the invention has some features in common with the system disclosed in US 6094937 in that use is made of several carriers and several buoy structures for fluid as a part of a transport system.
• the system according to the invention has to be used for unloading.
• a liquefier is provided on board the carrier in US 6094937
• a vaporizer is provided in the LNG tanker according to the invention.
• this loading/transport system will be capable of use in connection with unloading.
• a vessel like that in US 6094937 be able to be used for unloading natural gas to a shore-based infrastructure without the need for considerable structural modifications to the vessel.
• the vessel with its special functions should be able to form part of a shuttle system which in a preferred embodiment includes a plurality of vessels and a plurality of the buoy structures concerned.
• the object of this system is to achieve the continuous supply of natural gas from the unloading point to the infrastructure.
• the vessel is provided in a simple and inexpensive manner using a standard LNG carrier as the basis.
• the carrier with its storage tanks for liquefied natural gas is equipped with one or more vaporizers preferably in the deck area, and a receiving recess is constructed in the hull for receiving the buoy structure, thus making the vessel suitable for performing several types of operation.
• This special vessel is described as a "Shuttle and Regas Vessel (SRV)", and the vessel may of course also be used as an ordinary LNG carrier.
• the vessel according to the invention is equipped with spherical tanks for storing liquefied natural gas, but other types of storage tanks may also be suitable, such as, for example, membrane tanks. These different types of storage tanks are well-known both from the patent literature and in practical use. Thus it will be up to a person skilled in the art to select the type of tank which is most suitable in the individual case.
• the principles and equipment to be used in connection with the regasification of the liquefied natural gas also represent known per se technology.
• Sea water may be utilised as a heat exchange medium in the vaporization process, but also other media such as, for example, propane either alone or together with sea water, and a water-glycol mixture may be suitable vaporization media.
• the buoy structure which is to form part of the system may be designed in many ways. From the patent literature several examples are known of submerged buoy structures which can be connected to a vessel, thus enabling the vessel to rotate freely around the buoy. However, with regard to the buoy structure's mode of operation, rapid connection and disconnection of the buoy are a requirement in order that the unloading of fluid can start almost immediately without delays due to time-consuming mooring procedures.
• the buoy structure When the buoy structure is not in use, it is in a submerged condition. On arrival at the unloading area, the vessel will pick up an auxiliary buoy, which has a line attached to the buoy structure. The line is used to convey the buoy structure to the surface, whereupon the buoy structure is brought into abutment in the vessel's recess.
• buoy structure Around its circumference the buoy structure is equipped with mooring lines which extend down to the mooring points on the seabed. Risers are provided up to the middle of the buoy structure and a swivel structure is arranged above the buoy structure. By means of this arrangement fluid can be passed through the buoy structure via the riser to the submerged pipelines, while at the same time the vessel rotates around the buoy structure. The submerged pipelines transport fluid away from the vessel towards the shore-based infrastructure.
• the invention proposes a system for achieving an efficient unloading of fluid to a shore-based infrastructure.
• two buoy structures and two or more carrier vessels are included in the system.
• the number of vessels included in the system depends on the distance to the loading point.
• One and the same vessel will alternate between different operations such as loading from a loading station, for example in the field, transporting LNG from the loading station to the unloading point and regasifying liquefied natural gas with subsequent transfer to a receiving system on shore.
• the buoy structure On arrival at the unloading point, the buoy structure will be inserted in the receiving recess in the carrier vessel. Liquefied natural gas will be passed from the storage tanks to the vaporizer where the fluid is regasified and passed directly through the buoy structure to submerged pipelines which convey the natural gas to a shore-based infrastructure.
• the shore-based infrastructure may take many forms, as long as the infrastructure is suitable for receiving the regasified fluid which is sent ashore from the carrier and the fluid is further distributed to the end users.
• the infrastructure may comprise a pipeline network which conveys the natural gas directly to the end user or the infrastructure may comprise a depot which is connected to appropriate transport means for further transport of natural gas to the consumers, etc.
• fig. 1 is a side view of a carrier vessel with the necessary equipment.
• Fig. 2 is a perspective view of one of the vessels coupled up to one of the buoy structures.
• Fig. 3 is a perspective view of the connection of the pipelines with the infrastructure.
• Fig. 4 is a general view of the organisation of the vessels in order to obtain an efficient unloading of fluid.
• Fig. 5 illustrates the vessel connected to both buoy structures simultaneously.
• Fig. 1 is a simplified schematic view of the retrofitted LNG carrier "Shuttle and Regas Vessel (RSV)" according to the invention.
• the vessel 1 is illustrated provided with a plurality of tanks 2 for storing liquefied natural gas.
• the figure shows how in the vessel's hull there is provided a conical recess 5 which forms a receiving arrangement for the buoy structure 7 (not illustrated in the drawing).
• the vessel 1 is further provided with at least one vaporizer 4.
• the vessel is also equipped with thrusters 6 in the vessel's bow portion and stern portion respectively.
• Fig. 2 illustrates an arrangement of buoy structures 7 which are connected to a submerged pipeline system.
• the submerged pipeline system comprises a riser 8 which is attached to each of the buoy structures 7, and furthermore a pipeline 9 is connected to the end of the riser 8.
• the pipelines 9 are connected to an on-shore infrastructure, illustrated here in the figure by the pipeline system 10.
• the buoy structures 7 are equipped with mooring lines 1 1 extending from the mooring point on the seabed to an attachment on the circumference of the buoy structure.
• Figure 2 illustrates two vessels 1 where one of the vessels 1 is connected to one of the buoy structures 7, while the other vessel T illustrates the voyage to/from the loading point.
• the liquefied natural gas is transferred to the vaporizer 4, where the fluid is regasified before being transferred through the buoy structure 7 via the submerged pipelines 9 which are connected to yet another pipeline 10 for bringing natural gas ashore to the infrastructure.
• FIG. 3 illustrates the same situation as in figure 2, but in addition it also illustrates the pipeline system's connection to the infrastructure, which in this case is composed of a shore-based pipeline system 12.
• Fig. 4 illustrates the principle for the organisation of the connection of the various vessels to the buoy structures as well as transport to and from the loading station where LNG is loaded on board the vessel. In this example four vessels are included in the system.
• fig. 5 both the buoy structures are connected to the vessels 1 and 1' simultaneously.
• the vessel 1 is in the process of completing the unloading of natural gas, while the vessel 1' has just received the buoy structure 7 in the recess 5.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• Ocean & Marine Engineering (AREA)
• Filling Or Discharging Of Gas Storage Vessels (AREA)
• Ship Loading And Unloading (AREA)
• Physical Or Chemical Processes And Apparatus (AREA)
• Control And Safety Of Cranes (AREA)
• Information Transfer Between Computers (AREA)
• Circuits Of Receivers In General (AREA)
• Radar Systems Or Details Thereof (AREA)

Applications Claiming Priority (3)

Publications (2)

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ID=19912299

Family Applications (1)

Country Status (11)

Cited By (2)

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• 2001
  • 2001-03-23 NO NO20011524A patent/NO20011524L/no not_active Application Discontinuation
• 2002
  • 2002-03-18 WO PCT/NO2002/000112 patent/WO2002076819A1/fr not_active Application Discontinuation
  • 2002-03-18 KR KR10-2003-7012389A patent/KR20030090686A/ko not_active Application Discontinuation
  • 2002-03-18 ES ES02702993T patent/ES2257529T3/es not_active Expired - Lifetime
  • 2002-03-18 DK DK02702993T patent/DK1383676T3/da active
  • 2002-03-18 AT AT02702993T patent/ATE316489T1/de not_active IP Right Cessation
  • 2002-03-18 EP EP02702993A patent/EP1383676B1/fr not_active Revoked
  • 2002-03-18 PT PT02702993T patent/PT1383676E/pt unknown
  • 2002-03-18 CN CNB028104803A patent/CN1257085C/zh not_active Expired - Fee Related
  • 2002-03-18 DE DE60208877T patent/DE60208877T2/de not_active Revoked
  • 2002-03-18 JP JP2002575296A patent/JP2004525816A/ja active Pending

Non-Patent Citations (1)

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