Classifications

• • 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
  • F17C9/00—Methods or apparatus for discharging liquefied or solidified gases from vessels not under pressure
  • F17C9/02—Methods or apparatus for discharging liquefied or solidified gases from vessels not under pressure with change of state, e.g. vaporisation
  • F17C9/04—Recovery of thermal energy
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
  • F25J1/0002—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the fluid to be liquefied
  • F25J1/0022—Hydrocarbons, e.g. natural gas
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
  • F25J1/003—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production
  • F25J1/0032—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using the feed stream itself or separated fractions from it, i.e. "internal refrigeration"
  • F25J1/0045—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using the feed stream itself or separated fractions from it, i.e. "internal refrigeration" by vaporising a liquid return stream
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
  • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
  • F25J1/0221—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process using the cold stored in an external cryogenic component in an open refrigeration loop
  • F25J1/0223—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process using the cold stored in an external cryogenic component in an open refrigeration loop in combination with the subsequent re-vaporisation of the originally liquefied gas at a second location to produce the external cryogenic component
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
  • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
  • F25J1/0243—Start-up or control of the process; Details of the apparatus used; Details of the refrigerant compression system used
  • F25J1/0244—Operation; Control and regulation; Instrumentation
  • F25J1/0245—Different modes, i.e. 'runs', of operation; Process control
  • F25J1/0251—Intermittent or alternating process, so-called batch process, e.g. "peak-shaving"
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
  • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
  • F25J1/0243—Start-up or control of the process; Details of the apparatus used; Details of the refrigerant compression system used
  • F25J1/0257—Construction and layout of liquefaction equipments, e.g. valves, machines
  • F25J1/0275—Construction and layout of liquefaction equipments, e.g. valves, machines adapted for special use of the liquefaction unit, e.g. portable or transportable devices
  • F25J1/0277—Offshore use, e.g. during shipping
  • F25J1/0278—Unit being stationary, e.g. on floating barge or fixed platform
• • 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
  • F17C2221/00—Handled fluid, in particular type of fluid
  • F17C2221/03—Mixtures
  • F17C2221/032—Hydrocarbons
  • F17C2221/035—Propane butane, e.g. LPG, GPL
• • 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
  • F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
  • F17C2223/01—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by the phase
  • F17C2223/0146—Two-phase
  • F17C2223/0153—Liquefied gas, e.g. LPG, GPL
  • F17C2223/0161—Liquefied gas, e.g. LPG, GPL cryogenic, e.g. LNG, GNL, 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
  • F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
  • F17C2223/03—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by the pressure level
  • F17C2223/033—Small pressure, e.g. for liquefied gas
• • 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
  • F17C2227/00—Transfer of fluids, i.e. method or means for transferring the fluid; Heat exchange with the fluid
  • F17C2227/03—Heat exchange with the fluid
  • F17C2227/0302—Heat exchange with the fluid by heating
  • F17C2227/0309—Heat exchange with the fluid by heating using another fluid
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J2205/00—Processes or apparatus using other separation and/or other processing means
  • F25J2205/24—Processes or apparatus using other separation and/or other processing means using regenerators, cold accumulators or reversible heat exchangers

Definitions

• Methane or natural gas is liquefied at a production point for transport in atmospheric pressure containers by heat exchange with a cold liquid refrigerant which sustains its liquid state after heat exchange with the methane or natural gas.
• the heated liquid refrigerant along with the methane or natural gas is transported to a consumption point in substantially atmospheric pressure containers where the liquefied methane or natural gas is heat exchanged with the liquid refrigerant to heat the methane or natural gas to a gaseous state and cool the liquid refrigerant.
• the cool liquid refrigerant is then transported back to the production point in substantially atmospheric pressure containers where it is heat exchanged with methane or natural gas as in the beginning.
• the invention relates to a method of transporting methane or natural gas in the liquid state and preferably at approximately atmospheric pressure.
• stage (f) At the production point gaseous methane or na ural gas is cooled according to stage (a) by bringing it into heat exchange with the refrigerant supplied accord ing to stage (c).
• production point is meant the place where the natural gas or methane is liquefied for dispatch
• consumption point is meant the place where the liquid natural gas or methane is converted, on arrival, to the gaseous state.
• the above-mentioned reservoir can be arranged on a vehicle or built into a tanker.
• Liquid nitrogen for example, has the disadvantage of being relatively difficult to obtain, while it also has the drawback of having an atmospheric boiling point of approximately -196 C. In order, therefore, to transport nitrogen in the liquid state at atmospheric pressure in reservoirs from the consumption point to the production point it is necessary to cool the nitrogen to considerably below the atmospheric boiling point of methane or natural gas, for which purpose a relatively large amount of energy is required.
• Another drawback of nitrogen is that its atmospheric boiling point lies very far below the ambient temperature so that when giving oft" its cold to the methane or natural gas the liquid nitrogen will pass into the gaseous state. Since gaseous nitrogen has relatively few applications, it has to be discharged into the atmosphere, and this must be regarded as a loss.
• Liquid oxygen like nitrogen
• Another disadvantage arising from the use of liquid oxygen as refrigerant is that it is not really possible to transport the liquid oxygen from the consumption point to the production point in the same reservoirs as are used for conveying the liquid methane or natural gas from the production point to the consumption point.
• oxygen can form explosive mixtures with methane or natural gas.
• the atmospheric boiling point of oxygen like that of nitrogen, is very low, namely 183 C.
• the use of oxygen as refrigerant has also the same disadvantages as the use of nitrogen as refrigerant.
• the liquid oxygen will pass into the gaseous state and it is not always easy to find useful applications for these large quantities of gaseous oxygen. Discharging it into the atmosphere would, of course, mean an economic loss.
• liquid air as refrigerant in the above method has approximately the same drawbacks as the use of liquid oxygen as refrigerant.
• ammonia really suited for use as a refrigerant since its atmospheric freezing point lies relatively far above the atmospheric boiling point of methane or natural gas, namely at 77 C.
• ammonia has the disadvantage of having an atmospheric boiling point which lies far below the ambient temperature, namely at 33 C., so that when giving off cold to the methane or natural gas to be liquefied the liquid ammonia easily passes into the gaseous state with the result that difficulties arise at the production point with the storing of the gaseous ammonia. Since gaseous ammonia is poisonous it cannot be discharged into the atmosphere, but must be worked up, for example, into fertilizers.
• liquid refrigerant having an atmospheric freezing point below or slightly above the atmospheric boiling point of meth ane or natural gas, and having an atmospheric boiling point above or slightly below the ambient temperature.
• the atmospheric freezing point of the refrigerant according to the invention is at most approximately 20 C. above the atmospheric boiling point of methane or natural gas, but is preferably lower than this maximum value. If the atmospheric freezing point of the refrigerant were to be higher than said maximum value the refrigerant could not very Well be used since it would then solidify and consequently could no longer be pumped, at a temperature which is considerably higher than the atmospheric boiling point of methane or natural gas. This means that the methane or natural gas could not be cooled tr a suflicient extent with the refrigerant alone, thus making an extra cooling plant necessary.
• the atmospheric boiling point of the refrigerant according to the invention is at most approximately 30 C. below the ambient temperature, but is preferably higher than this value.
• a refrigerant which is very suitable for use with the method of the invention is isopentane, which has an atmospheric freezing point of 160 C. and an atmospheric boiling point of +28 C. and which is moreover readily available in large quantities at a reasonable price.
• is isobutane which has an atmospheric freezing point of 160 C. and an atmospheric boiling point of l2 C.
• a drawback of this substance is, however, that the atmospheric boiling point is rather on the low side.
• methyl ether with an atmospheric freezing point of 138 C. and an atmospheric boiling point of 8 C.
• 2-methyl pentane with an atmospheric freezing point of -154 C. and an atmospheric boiling point of +60 C.
• a drawback of methyl ether is, however, that the atmospheric freezing point is rather on the high side, while the atmospheric boiling point is rather on the low side.
• mixtures having both an atmospheric freezing point and an atmospheric boiling point within the said ranges.
• examples of such mixtures are mixtures of isopentane or isobutane.
• Further examples are mixtures of isopentane and isohexane or mixtures of isopentane and normal pentane.
• Particularly suitable is a mixture container 75% isopentane and 25% isohexane which remains a liquid to minus 170 C., that is 10 C. lower than for pure isopentane. Since methane liquefies under atmospheric pressure at minus 160 C. the use of this type of refrigerant makes it possible to install all refrigeration capacity at the gas consumption p'oint.
• Suitable mixtures may furthermore, for example, also be those which have an eutectic point in the freezing point.
• mixtures which may be considered for use are, for example, hydrocarbon fractions with a boiling range below approximately 100 C., preferably between 35 C. and 75 C., obtained by distillation of crude petroleum or of a petroleum fraction which has been subjected to a cracking process.
• hydrocarbon fractions with a boiling range below approximately 100 C., preferably between 35 C. and 75 C., obtained by distillation of crude petroleum or of a petroleum fraction which has been subjected to a cracking process.
• These mixtures consist substantially of paraffinic and olefinic hydrocarbons having 5 and 6 carbon atoms.
• the refrigerant having been cooled at the consumption point, is preferably transported to the production point in the tanks which have been used for conveying the liquid methane or natural gas from the production point to the consumption point.
• This procedure has the advantage that the tanks are invariably maintained at a low temperature so that heating and cooling of the tanks do not occur.
• the refrigerant having been heated at the production point can if desired be used up on the spot, as fuel for example, or if desired, it can be transported to the consumption point to be there brought into heat exchange with an amount of liquid methane or natural gas which has to be converted into the gaseous state.
• the refrigerants mentioned may also be used in storage of methane or natural gas for peakshaving purposes.
• this can be liquefied by passing it in heat exchange with the cold refrigerant, for example, cold isopentane.
• the methane or natural gas thus liquefied can then be stored in suitable reservoirs and in periods of large demand for natural gas or methane the latter is gasified by passing it in heat-exchange with the warm isopentane.
• the cooled down isopentane is then stored until a period of small demand for natural gas or methane arrives again.
• the cold isopentane is used for liquefying a quantity of methane or natural gas which is stored until the demand for natural gas or methane rises again.
• a method of transporting a gas comprising the following stages:
• a first quantity of gas is liquefied at a production point by cooling and is passed in the liquid state into a reservoir in which a pressure of at least approximately one atmosphere is maintained;
• the liquid gas is converted to the gaseous state by bringing it into heat exchange with a liquid refrigerant having an atmospheric pressure boiling temperature above or slightly below the ambient temperature and an atmospheric pressure freezing temperature below or slightly above the atmospheric pressure boiling temperature of said gas to further cool said refrigerant within the liquid phase range;
• the insulated reservoir filled with said cooled liquid refrigerant is transferred to the gas production point, said refrigerant being preserved in the liquid phase at approximately one atmosphere pressure by the insulation of said reservoir;
• liquid refrigerant remains in the liquid state throughout all stages of said method.
• a method of converting liquid methane to the gaseous state by bringing it into heat exchange with a liquid refrigerant which is cooled off thereby, said liquid refrigerant having an atmospheric freezing point not substantially greater than 20 degrees C. above the atmospheric boiling point of methane, and having an atmospheric boiling point not substantially greater than 30 degrees C. below the ambient temperature.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Ocean & Marine Engineering (AREA)
• Separation By Low-Temperature Treatments (AREA)
• Filling Or Discharging Of Gas Storage Vessels (AREA)

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Cited By (6)

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Citations (11)

• 0
  • GB GB1054149D patent/GB1054149A/en not_active Expired
  • DE DENDAT1245999D patent/DE1245999B/de active Pending
• 1964
  • 1964-11-09 NL NL6413015A patent/NL6413015A/xx unknown
• 1965
  • 1965-11-03 US US506264A patent/US3324670A/en not_active Expired - Lifetime
  • 1965-11-08 ES ES0319333A patent/ES319333A1/es not_active Expired
  • 1965-11-08 FR FR37634A patent/FR1453574A/fr not_active Expired

Patent Citations (11)

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