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
  • C10L1/00—Liquid carbonaceous fuels
  • C10L1/32—Liquid carbonaceous fuels consisting of coal-oil suspensions or aqueous emulsions or oil emulsions
  • C10L1/328—Oil emulsions containing water or any other hydrophilic phase

Definitions

• the invention relates to a method for preventing or retarding the formation of hydrates or for reducing the tendency of hydrates to agglomerate during the transport of a fluid through a conduit.
• glycols e.g. ethylene glycol or diethylene glycol.
• a disadvantage thereof is that large amounts of glycol are needed (in the order of 30% by weight calculated on the amount of water).
• composition suitable for the prevention of hydrate formation which composition comprises diethylene glycol with a minor amount of alkyl aryl sulphonate (in a quantity of 0.3-0.5% based on the weight of the diethylene glycol).
• alkyl aryl sulphonic acids or alkali metal- or ammonium salts thereof can be used without glycols, to control hydrate formation.
• the invention relates to a method for preventing or retarding the formation of hydrates or for reducing the tendency of hydrates to agglomerate in a stream of fluid comprising water and hydrocarbon during transport of the fluid through a conduit, which method comprises adding to the fluid an alkyl aryl sulphonic acid or an alkali metal- or ammonium salt thereof substantially in the absence of glycol flowing in the stream.
• the hydrocarbon may be a liquid or a gas, but is preferably a gas such as methane, ethane, propane, isopropane, butane or isobutane.
• the fluid may be produced from oil wells as well as from gas wells.
• the fluid may also include natural gas.
• hydrates may be formed at temperatures well above the freezing point of water.
• Ethane hydrates for example, are formed at pressures between 10 and 30 bar (1 and 3 MPa) and temperatures between 4 °C and 14 °C. Formation and agglomeration of hydrate crystals will thus easily occur in pipelines surrounded by a cold atmosphere.
• the problem of formation and agglomeration of gas hydrates is not limited to gas wells, but also occurs in oil wells, if water and gas are present in the fluid.
• the alkyl aryl sulphonic acids or their salts preferably have an aryl group derived from benzene, toluene, ortho-, meta- or para-xylene.
• the alkyl group is preferably a long chain alkyl group, which may be branched or straight.
• the alkyl group may be e.g. a C8-C22-alkyl group.
• Preferred compounds are those of the chemical formula wherein X is H, Na or K and R is a C8-C22 alkyl group.
• More preferred compounds are those wherein R is a C13 and/or C14 alkyl or a C18-alkyl group, such as those known under the trade name DOBANAX-320, DOBANAX-313 and DOBANAX-205.
• dialkyl benzene sulphonates of the chemical structure wherein X is an alkali metal and R1 and R2 are the same or different C2-C20-alkyl groups, preferably C6-C14-alkyl groups.
• the alkyl aryl sulphonates are added in quantities from 0.1 per cent to 3 per cent by weight, calculated on the weight of the water present in the fluid.
• a preferred range is from 0.2 to 1 percent, more preferred in the range of from 0.3 to 0.6 per cent.
• the cell was made of stainless steel and had a cooling jacket to allow a good and easy temperature control of the cell. Two sapphire windows allowed visual observation of the cell content.
• the cell was provided with two valves one for the introduction of liquid and one for gas.
• a stirring bar cared for good mixing of the cell content.
• the inner volume of the cell was 66.4 ml and dead volumes were reduced to a minimum.
• the cell was further tested together with its loading system at a pressure of 100 bar over a period of 80 hours without any pressure drop being observed. The cell usually worked at a pressure of below 30 bar.
• the cell was located in a plexiglass cage.
• a personal computer based data acquisition system allowed the measurement of the temperature and pressure inside the cell once per minute.
• a steel well went deeply inside the cell in which a platinum resistance thermometer was introduced.
• On the cell was mounted a pressure transducer, with a very small temperature hysteresis and a high accuracy.
• the cell was rinsed with demineralized water, rinsed with ethanol and vacuum dried, all without dismounting the cell.
• demineralized water and decane were introduced as liquid into the cell.
• the water contained 0.5% per cent by weight of alkyl aryl sulphonic acid or salt thereof, if desired.
• Ethane was introduced as a gas into the cell.
• the run started at 20 °C and the temperature in the cell was dropped, via the jacket connected to the thermostatic bath by lowering its temperature.
• the amounts of water, decane and ethane were 25, 5.8 and 4.7 grams respectively.
• the pressure was 25 bar at 20 °C, and no ethane hydrates were formed.
• thermometer sent a digital signal, the pressure meter an analog signal, to the computer.
• the computer could also send a set point command to the thermostatic bath.
• the temperature and the pressure of the cell were recorded, together with the time, at every minute.
• a temperature-time and a pressure-time curve could be made.

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• 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)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=10671171

Family Applications (1)

Country Status (7)

Cited By (17)

Families Citing this family (5)

Citations (3)

• 1990
  • 1990-02-16 GB GB909003617A patent/GB9003617D0/en active Pending
• 1991
  • 1991-02-05 NZ NZ237020A patent/NZ237020A/en unknown
  • 1991-02-08 DE DE91200272T patent/DE69100197T2/de not_active Expired - Fee Related
  • 1991-02-08 DK DK91200272.2T patent/DK0457375T3/da active
  • 1991-02-08 EP EP91200272A patent/EP0457375B1/fr not_active Expired - Lifetime
  • 1991-02-11 CA CA002036084A patent/CA2036084A1/fr not_active Abandoned
  • 1991-02-15 NO NO910619A patent/NO180783C/no unknown

Patent Citations (3)

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