[go: up one dir, main page]

WO2001040413A1 - Storage of natural gas - Google Patents

Storage of natural gas Download PDF

Info

Publication number
WO2001040413A1
WO2001040413A1 PCT/AU2000/001481 AU0001481W WO0140413A1 WO 2001040413 A1 WO2001040413 A1 WO 2001040413A1 AU 0001481 W AU0001481 W AU 0001481W WO 0140413 A1 WO0140413 A1 WO 0140413A1
Authority
WO
WIPO (PCT)
Prior art keywords
natural gas
reservoir
liquefied natural
gas
boil
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/AU2000/001481
Other languages
French (fr)
Inventor
Robert Amin
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Metasource Pty Ltd
Woodside Energy Ltd
Original Assignee
Metasource Pty Ltd
Woodside Energy Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Metasource Pty Ltd, Woodside Energy Ltd filed Critical Metasource Pty Ltd
Priority to AU18441/01A priority Critical patent/AU1844101A/en
Publication of WO2001040413A1 publication Critical patent/WO2001040413A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
    • C10L3/00—Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas
    • C10L3/06—Natural gas; Synthetic natural gas obtained by processes not covered by C10G, C10K3/02 or C10K3/04

Definitions

  • the present invention relates to the storage of natural gas. More particularly, the present invention relates to the storage of liquefied natural gas and the retention of the boil off gas that results from such storage.
  • natural gas shall be taken as including natural gas, petroleum gas, butane, propane, ethane and like fuel gasses.
  • natural gas hydrate shall be taken as including hydrates formed from natural gas, associate gas, butane, propane, ethane, methane and like fuel gasses
  • Liquefied natural gas or "LNG” is conventionally stored as an extremely cold liquid under one atmospheric pressure and at -161 °C. With the transfer of heat to the stored LNG the temperature of the LNG will rise to its boiling point. However, such heat will be dissipated as latent heat as a result of the boiling of the LNG which, in the absence of further heat input, will lower the temperature. This phenomenon is called auto-refrigeration and necessitates the removal of the boil off gas from above the LNG to maintain a substantially constant pressure above the LNG The amount of boil off gas generated can be of the order of 1 -5% of the volume of LNG per day.
  • the boil-off gas is reliquefied, by cooling and pressu ⁇ sation, before being reintroduced to the storage vessel.
  • This process is carried out continuously, is energy intensive and as a result presents a significant economic impediment to the storage and transportation of LNG, particularly in the Tropics and sub-Tropics.
  • It an object of the present invention to provide a more efficient means of storing LNG.
  • a method for the storage of natural gas comprising:
  • the liquefied natural gas is used to cool the boil off gas and the water used to form the natural gas hydrate.
  • the boil-off gas is cooled by utilising a heat exchanger that utilises liquefied natural gas extracted from the reservoir as the heat exchange medium.
  • the water is cooled by utilising a heat exchanger that utilises liquefied natural gas extracted from the reservoir as the heat exchange medium.
  • the liquefied natural gas used to cool the boil-off gas and the water is returned to the liquefied natural reservoir.
  • the liquefied natural gas used to cool the boil-off gas and the water is vaporised for storage as compressed natural gas and/or delivery for consumption.
  • a natural gas storage facility comprising an insulated reservoir adapted to store liquefied natural gas, an extraction means for the extraction of boil off gas from the reservoir to maintain the pressure above the liquefied natural gas substantially constant, and a hydrate production means which utilises the boil-off gas for the production of natural gas hydrate.
  • the facility further comprises a heat exchanger which is connected to the extraction means to cool the boil off gas prior to its delivery to the hydrate production means.
  • the heat exchanger is used to cool water which is to be used in the production of the natural gas hydrate.
  • the heat exchanger utilises liquefied natural gas drawn from the reservoir as the heat exchange medium.
  • the outlet for the heat exchange medium from the heat exchanger is adapted to deliver the liquefied natural gas to the reservoir.
  • the outlet for the heat exchange medium from the heat exchanger is adapted to deliver the liquefied natural gas to a vaporiser.
  • the liquefied natural gas in the reservoir is used as a heat exchange medium in the hydrate production means.
  • the heat exchange medium is returned to the reservoir.
  • the heat exchange medium is delivered to a vaporiser.
  • the embodiment is directed to a storage facility for liquefied natural gas.
  • the storage facility which is illustrated schematically in the accompanying drawing comprises a substantially conventional storage reservoir 10 for storing LNG at a substantially constant pressure and temperature at most equal to its boiling point at that pressure.
  • the boil off gas is extracted through a vapour outlet 12 in the reservoir. According to conventional practice the extracted boil off gas is liquefied and returned to the reservoir.
  • the reservoir is associated with a facility 20 for the production of natural gas hydrate from the boil off gas.
  • the outlet 12 is connected to a compressor 14 which is in turn connected to a first heat exchanger 16 which is intended to cool the boil off gas.
  • the water which is required to for the natural gas hydrate production is cooled under pressure in a second heat exchanger 18.
  • the cooled boil off gas and water is then delivered to a reactor 20 to form natural gas hydrate which is stored in association with the LNG.
  • the formation of the natural gas hydrate may be in accordance with the methods which are the subject of co-pending International patent applications PCT/AUOO/00719 and PCT/AU00/00973.
  • the heat exchange medium of both the first and the second heat exchangers 16 and 18 comprises LNG which is extracted from the reservoir 10 through a delivery line 22.
  • the heat exchange medium (LNG) which is exhausted from the heat exchangers through the exhaust line 24 can be returned to the reservoir 10 through a first valve 26 where the returned LNG will be cooled by the ever present auto-refrigeration which is a characteristic of LNG storage.
  • the heat exchange medium (LNG) which is exhausted from the heat exchangers through the exhaust line 24 can be delivered to a vaporiser through a second valve 28 whereby the resultant gas can be stored as compressed natural gas, delivered to a distribution network for delivery to consumers or consumed.
  • the embodiment provides a means for the storage of the LNG which need not be associated with a means for the liquefaction of the boil off gas along with the high energy demands of such a facility.
  • the boil off gas is used a feed stock for the production of natural gas hydrate which is able to be stored relatively efficiently.
  • the stored LNG is used as the heat exchange medium in the production of the gas hydrate.
  • the embodiment provides a means of efficiently vaporising LNG at the delivery point for the natural gas whereby the heat generated by the hydration process is used to vaporise the LNG.
  • the embodiment can be used in facilities for the long term storage of LNG, transport facilities and at the point of delivery to customers.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Filling Or Discharging Of Gas Storage Vessels (AREA)

Abstract

A method for the storage of natural gas comprising the steps of: storing the natural gas as liquefied natural gas in an insulated storage reservoir; maintaining the pressure above the liquefied natural gas substantially constant by withdrawing the boil-off gas from the reservoir; combining the withdrawn liquefied natural gas with water to form natural gas hydrate; and storing the natural gas hydrate so formed.

Description

'STORAGE OF NATURAL GAS'
Field of the Invention
The present invention relates to the storage of natural gas. More particularly, the present invention relates to the storage of liquefied natural gas and the retention of the boil off gas that results from such storage.
Throughout the specification the term natural gas shall be taken as including natural gas, petroleum gas, butane, propane, ethane and like fuel gasses. Similarly the term natural gas hydrate shall be taken as including hydrates formed from natural gas, associate gas, butane, propane, ethane, methane and like fuel gasses
Background Art
Liquefied natural gas, or "LNG", is conventionally stored as an extremely cold liquid under one atmospheric pressure and at -161 °C. With the transfer of heat to the stored LNG the temperature of the LNG will rise to its boiling point. However, such heat will be dissipated as latent heat as a result of the boiling of the LNG which, in the absence of further heat input, will lower the temperature. This phenomenon is called auto-refrigeration and necessitates the removal of the boil off gas from above the LNG to maintain a substantially constant pressure above the LNG The amount of boil off gas generated can be of the order of 1 -5% of the volume of LNG per day. Conventionally, the boil-off gas is reliquefied, by cooling and pressuπsation, before being reintroduced to the storage vessel. This process is carried out continuously, is energy intensive and as a result presents a significant economic impediment to the storage and transportation of LNG, particularly in the Tropics and sub-Tropics.
If the boil off gas is not drawn off from the reservoir the pressure above the LNG will increase resulting in the boiling point of the LNG being raised and with the absorption of stray heat, the temperature of the LNG will continue to rise unless an alternative means is provided to dissipate the absorbed heat. The net effect of such will be that the temperature of the LNG to continue to rise with the continued absorption of heat unless a cooling facility is provided to accommodate for such absorption. In order to eliminate the requirement of additional cooling the pressure above the LNG is kept substantially constant and the latent heat absorbed by the vaporisation of the LNG is utilised.
It an object of the present invention to provide a more efficient means of storing LNG.
Disclosure of the Invention
In accordance with the present invention, there is provided a method for the storage of natural gas, the method comprising:
storing the natural gas as liquefied natural gas in an insulated storage reservoir;
maintaining the pressure of the liquefied natural gas substantially constant by withdrawing the boil-off gas from the reservoir;
combining the withdrawn liquefied natural gas with water to form natural gas hydrate; and
storing the natural gas hydrate so formed.
According to a preferred feature of the invention the liquefied natural gas is used to cool the boil off gas and the water used to form the natural gas hydrate. According to a preferred feature of the invention, the boil-off gas is cooled by utilising a heat exchanger that utilises liquefied natural gas extracted from the reservoir as the heat exchange medium. According to a preferred feature of the invention, the water is cooled by utilising a heat exchanger that utilises liquefied natural gas extracted from the reservoir as the heat exchange medium. According to one embodiment of the invention, the liquefied natural gas used to cool the boil-off gas and the water is returned to the liquefied natural reservoir. According to a second embodiment of the invention, the liquefied natural gas used to cool the boil-off gas and the water is vaporised for storage as compressed natural gas and/or delivery for consumption.
In accordance with the present invention there is provided a natural gas storage facility comprising an insulated reservoir adapted to store liquefied natural gas, an extraction means for the extraction of boil off gas from the reservoir to maintain the pressure above the liquefied natural gas substantially constant, and a hydrate production means which utilises the boil-off gas for the production of natural gas hydrate.
According to a preferred feature of the invention the facility further comprises a heat exchanger which is connected to the extraction means to cool the boil off gas prior to its delivery to the hydrate production means. According to a further preferred feature of the invention the heat exchanger is used to cool water which is to be used in the production of the natural gas hydrate. According to a particular embodiment of the invention the heat exchanger utilises liquefied natural gas drawn from the reservoir as the heat exchange medium. According to a feature of the embodiment the outlet for the heat exchange medium from the heat exchanger is adapted to deliver the liquefied natural gas to the reservoir. According to an alternative or supplementary feature of the embodiment the outlet for the heat exchange medium from the heat exchanger is adapted to deliver the liquefied natural gas to a vaporiser.
According to a preferred feature of the invention the liquefied natural gas in the reservoir is used as a heat exchange medium in the hydrate production means. According to one embodiment the heat exchange medium is returned to the reservoir. According to a supplementary feature of the embodiment or an alternative embodiment the heat exchange medium is delivered to a vaporiser.
The invention will be more fully understood in the light of the following description of several specific embodiments. Brief Description of the Drawing
The description of the embodiment is made with reference to the accompanying drawing, which is a schematic representation of a storage facility according to the embodiment.
Detailed Description of Specific Embodiments
The embodiment is directed to a storage facility for liquefied natural gas. The storage facility which is illustrated schematically in the accompanying drawing comprises a substantially conventional storage reservoir 10 for storing LNG at a substantially constant pressure and temperature at most equal to its boiling point at that pressure. In order to enable the pressure above the LNG to remain substantially constant, the boil off gas is extracted through a vapour outlet 12 in the reservoir. According to conventional practice the extracted boil off gas is liquefied and returned to the reservoir.
In the case of the embodiment the reservoir is associated with a facility 20 for the production of natural gas hydrate from the boil off gas. To this end the outlet 12 is connected to a compressor 14 which is in turn connected to a first heat exchanger 16 which is intended to cool the boil off gas. In addition the water which is required to for the natural gas hydrate production is cooled under pressure in a second heat exchanger 18. The cooled boil off gas and water is then delivered to a reactor 20 to form natural gas hydrate which is stored in association with the LNG. In this regard the formation of the natural gas hydrate may be in accordance with the methods which are the subject of co-pending International patent applications PCT/AUOO/00719 and PCT/AU00/00973.
The heat exchange medium of both the first and the second heat exchangers 16 and 18 comprises LNG which is extracted from the reservoir 10 through a delivery line 22. The heat exchange medium (LNG) which is exhausted from the heat exchangers through the exhaust line 24 can be returned to the reservoir 10 through a first valve 26 where the returned LNG will be cooled by the ever present auto-refrigeration which is a characteristic of LNG storage. Alternatively or in addition the heat exchange medium (LNG) which is exhausted from the heat exchangers through the exhaust line 24 can be delivered to a vaporiser through a second valve 28 where whereby the resultant gas can be stored as compressed natural gas, delivered to a distribution network for delivery to consumers or consumed.
The embodiment provides a means for the storage of the LNG which need not be associated with a means for the liquefaction of the boil off gas along with the high energy demands of such a facility. Instead according to the embodiment the boil off gas is used a feed stock for the production of natural gas hydrate which is able to be stored relatively efficiently. Furthermore the stored LNG is used as the heat exchange medium in the production of the gas hydrate. In addition the embodiment provides a means of efficiently vaporising LNG at the delivery point for the natural gas whereby the heat generated by the hydration process is used to vaporise the LNG.
The embodiment can be used in facilities for the long term storage of LNG, transport facilities and at the point of delivery to customers.
Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.
It should be appreciated that the scope of the invention need not be limited to the particular scope of the embodiment described above.

Claims

The claims defining the invention are as follows:
1 A method for the storage of natural gas comprising the steps of
storing the natural gas as liquefied natural gas in an insulated storage reservoir,
maintaining the pressure of the liquefied natural gas substantially constant by withdrawing the boil-off gas from the reservoir,
combining the withdrawn liquefied natural gas with water to form natural gas hydrate, and
storing the natural gas hydrate so formed
2 A method according to claim 1 characterised in that the liquefied natural gas is used to cool the boil off gas and the water used to form the natural gas hydrate
3 A method according to claim 2 characterised in that the boil-off gas is cooled by utilising a heat exchanger which utilises liquefied natural gas extracted from the reservoir as the heat exchange medium
4 A method according to claim 2 or 3 characterised in that the water is cooled by utilising a heat exchanger which utilises liquefied natural gas extracted from the reservoir as the heat exchange medium
A method according to claim 4 characterised in that the liquefied natural gas used to cool the boil-off gas and the water is returned to the liquefied natural reservoir
A method according to claim 4 characterised in that the liquefied natural gas used to cool the boil-off gas and the water is vaporised for storage as compressed natural gas and/or delivery for consumption A natural gas storage facility comprising an insulated reservoir adapted to store liquefied natural gas, an extraction means for the extraction of boil off gas from the reservoir to maintain the pressure above the liquefied natural gas substantially constant, and a hydrate production means which utilises the boil- off gas for the production of natural gas hydrate
A natural gas storage facility according to claim 7 characterised in that the facility further comprises a heat exchanger which is connected to the extraction means to cool the boil off gas prior to its delivery to the hydrate production means
A natural gas storage facility according to claim 8 characterised in that the heat exchanger is used to cool water which is to be used in the production of the natural gas hydrate
A natural gas storage facility according to claim 9 characterised in that invention the heat exchanger utilises liquefied natural gas drawn from the reservoir as the heat exchange medium
A natural gas storage facility according to claim 10 characterised in that the outlet for the heat exchange medium from the heat exchanger is adapted to deliver the liquefied natural gas to the reservoir
A natural gas storage facility according to claim 10 or 1 1 characterised in that the outlet for the heat exchange medium from the heat exchanger is adapted to deliver the liquefied natural gas to a vaporiser
A natural gas storage facility according to claim 11 or 12 characterised in that the liquefied natural gas in the reservoir is used as a heat exchange medium in the hydrate production means
A natural gas storage facility according to claim 13 characterised in that the heat exchange medium is returned to the reservoir
15. A natural gas storage facility according to claim 13 or 14 characterised in that the heat exchange medium is delivered to a vaporiser.
16. A method for the storage of natural gas substantially as described herein with reference to the embodiment.
17. A natural gas storage facility substantially as described herein with reference to the embodiment.
PCT/AU2000/001481 1999-12-01 2000-11-30 Storage of natural gas Ceased WO2001040413A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU18441/01A AU1844101A (en) 1999-12-01 2000-11-30 Storage of natural gas

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AUPQ4382 1999-12-01
AUPQ4382A AUPQ438299A0 (en) 1999-12-01 1999-12-01 Storage of natural gas

Publications (1)

Publication Number Publication Date
WO2001040413A1 true WO2001040413A1 (en) 2001-06-07

Family

ID=3818524

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/AU2000/001481 Ceased WO2001040413A1 (en) 1999-12-01 2000-11-30 Storage of natural gas

Country Status (2)

Country Link
AU (1) AUPQ438299A0 (en)
WO (1) WO2001040413A1 (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04316795A (en) * 1991-04-16 1992-11-09 Tokyo Gas Co Ltd natural gas storage system
WO1993001153A1 (en) * 1990-01-29 1993-01-21 Jon Steinar Gudmundsson Method for production of gas hydrates for transportation and storage
US6028234A (en) * 1996-12-17 2000-02-22 Mobil Oil Corporation Process for making gas hydrates

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1993001153A1 (en) * 1990-01-29 1993-01-21 Jon Steinar Gudmundsson Method for production of gas hydrates for transportation and storage
JPH04316795A (en) * 1991-04-16 1992-11-09 Tokyo Gas Co Ltd natural gas storage system
US6028234A (en) * 1996-12-17 2000-02-22 Mobil Oil Corporation Process for making gas hydrates

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Derwent World Patents Index; Class Q69, AN 1992-420511/51 *

Also Published As

Publication number Publication date
AUPQ438299A0 (en) 1999-12-23

Similar Documents

Publication Publication Date Title
KR100929250B1 (en) Fuel gas supply system and method of ship
US7644676B2 (en) Storage tank containing liquefied natural gas with butane
US7478975B2 (en) Apparatus for cryogenic fluids having floating liquefaction unit and floating regasification unit connected by shuttle vessel, and cryogenic fluid methods
CN109312897B (en) Device and method for cooling liquefied gas and/or natural boil-off gas from liquefied gas
US4315407A (en) Gas storage and transmission systems
KR101075195B1 (en) Natural gas fuel supply system including storage tank with heat exchanger and storage tank
KR101567856B1 (en) Container carrier carrying reefer container
AU2012364280B2 (en) Methods for storing cryogenic fluids in storage vessels
CN103759497B (en) Installation structure of small skid-mounted LNG boil-off gas reliquefaction recovery device
KR20080085645A (en) Evaporative gas treatment method and treatment apparatus in a LAN carrier equipped with a reliquefaction apparatus, and a LAN carrier equipped with the treatment apparatus
KR102418019B1 (en) Lng boil-off re-liquefaction system for small and medium lng fuel propulsion ships and method to re-liquefaction lng boil-off using therefore
KR20110046946A (en) A system for supplying fuel gas to a liquefied fuel gas propulsion vessel having a high pressure gas injection engine and a low pressure gas injection engine.
KR20140146802A (en) Regasification System and Method of LNG
US3760597A (en) Short term storage of natural gas
CN103759498A (en) Pumpless circulation method for small skid-mounted evaporation gas reliquefaction and recovery device for liquefied natural gas
WO2001040413A1 (en) Storage of natural gas
KR102388679B1 (en) Lng boil-off re-liquefaction system for small and medium lng fuel propulsion ships and method to re-liquefaction lng boil-off using therefore
KR20010077227A (en) Reliquefication system of boiled-off-gas using cold energy in LNG and mothod therefor
KR20220070605A (en) Design system of a combination of a liquefied natural gas and a liquid hydrogen receiving terminal
US20040154315A1 (en) Method for vaporizing and heating compressed liquefied gases
KR20110046945A (en) A system for supplying fuel gas to a liquefied fuel gas propulsion vessel having a high pressure gas injection engine and a low pressure gas injection engine.
Cui et al. Performance improvement of a boil-off gas re-condensation process with pre-cooling at LNG terminals
KR102596630B1 (en) Fuel providing system used for ship, and liquefied gas fueled ship having the same
Bahgat Proposed method for dealing with boil-off gas on board LNG carriers during loaded passage
KR101215635B1 (en) fuel gas supply system

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CR CU CZ DE DK DM DZ EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG US UZ VN YU ZA ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR BF BJ CF CG CI CM GA GN GW ML MR NE SN TD TG

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP