DE1501748A1 - Method of transporting gas - Google Patents

Description

SHELL INTERNATIONAL RESEARCH MAATSCHAPPIJ N.V., 30, Carel van Bylandtlaan, The Hague, a Netherlands Comp.

concerning
Method of transporting gas

The invention relates to a method for transporting gas, in particular methane or natural gas, in liquid state.

As is known, gas can be liquefied by deep-freezing at the point of generation to facilitate transport will. For gases with a relatively low boiling point at atmospheric pressure, such as methane or natural gas, Relatively large amounts of energy are required for liquefaction. The costs for the Liquefaction plant relatively high. It is therefore desirable to find aids in reducing it to find out the amount of energy necessary to liquefy the gas at the place of production.

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A method of transporting gas in a liquid state has already been used for this purpose which includes the following stages "

a) The gas is liquefied by cooling at the point of generation and introduced into a container in a liquid state;

b) this filled storage container is transported to the place of consumption;

c) at the point of consumption, the liquefied gas is converted into a gaseous gas by heat exchange with a coolant State transferred;

d) the coolant cooled down during process stage c) is introduced into a storage container;

e) according to stage d) with the cooled-down coolant filled storage container is transported to the place of production;

f) at the place of production, the gas according to stage a) is exchanged with the gas according to process stage e) Provided coolant is cooled.

In this application, the "place of production" is the place where the gas is liquefied while under "place of consumption" is to be understood the place where the liquefied gas after its arrival for the Consumption is converted into the gaseous state.

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In the above process, the coolant and thus that for gas liquefaction are required .energy returned to the place of generation. The coolant should be able to hold large amounts of kiilt per unit volume, sodai? the one for transporting the coolant required container space can be as small as possible. So for this purpose the coolant should have a relatively high specific 7 / poor and a relatively high density. In addition, the coolant still has to be It must be easy to use if it satisfies the following requirements and transportable, it should be readily available and cheap and cheap freezer and Have boiling points.

According to the invention, all coolants should now be water, mixed with at least one agent to reduce frozen levels be used. There are no coolants e.g. water mixed with ammonia (2.Ή,); oier water., mixed with at least one alcohol, e.g. wetter with the addition of methanol (CH, OH) or ethanol

p; or “water mixed with, two or more alcohols or other surf dances. With a glycol, e.g. ~. WaSSCr ₄ mixed with diethylene glycol C ₂ h \ (OH) ₂ can also be used as a coolant. It was found that iai a mixture of 66 J £ ol- ^ H ₂ O and 34 Llolfi NH, has a freezing point of -100 ⁰ C;

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BATH ORIGINAL '

this is approximately the condensation temperature of Natural gases at 30 to 4-0 ata, such as natural gas from the Sahara, Libya or Groningen.

The liquefied gas can be transported in the storage container at a pressure of one atmosphere will; however, in many cases higher pressures are appropriate.

The cooled-down coolant is used at the point of generation to liquefy a quantity of gas by the coolant is allowed to cool the gas until it liquefies. As a result, the temperature of the rises Coolant, i.e. it is heated up to ambient temperature, for example. Optionally, the coolant can are now consumed at the place of production, e.g. for processes in the chemical industry that take place at the place of production be performed. The mixture of water and ammonia can be used e.g. for the production of fertilizers will. It is also possible to use ammonia, alcohols or others to lower the freezing point Separate the gown from the water at the place of production. These isolated means for lowering the freezing point can either consumed on the spot or returned to the place of consumption. In the latter case the means for lowering the freezing point can be mixed again with a certain amount of water for

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Production of the necessary coolant, which after the arrival of liquefied gas at the place of consumption is used to convert this into the gaseous state; then the cooled down Coolant brought back to the place of production. It is of course also possible to take the funds to freezing point There is a need not to isolate at the place of production, but to combine the "heated" coolant as a whole Manage containers and transport them from the place of production to the place of consumption. In most cases it is preferred to bring the coolant to the place of consumption at atmospheric pressure or about atmospheric pressure, although higher pressures can of course also be used. In many cases this can be done at the place of consumption cooled down coolant to the place of production advantageously transported in the same container that was used to transport the liquefied gas from the place of production to the place of consumption. This has the advantage that the container is kept unchanged at a low temperature and therefore at the place of production does not need to be cooled. As a result of the high density and the high specific heat of the proposed Coolant is the space of the storage tank in which the liquefied gas from the place of production to Place of consumption has been transported, in many cases, large enough to contain the cooled refrigerant to be transported from the place of consumption to the place of production.

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Of course, the containers can be used to transport the liquefied gas and / or the coolant be installed in a ship, a railroad car, a lorry or another vehicle or represent part of the same.

The method described can be used for the transport of liquefied natural gas, methane, ethane, propane, Butane or other liquefied gases can be used. The selected concentrations of the freezing point depressant Means in the water depend on which gas is to be liquefied · At Natural gas and methane usually have to be used in larger quantities, since they have a lower temperature for liquefaction is necessary, whereby of course the pressure applied also plays a role.

The following is an overview based on examples are given via the transport of natural gases using various coolants.

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Quantity of natural gas to be transported: 6000 t per day of production

Coolant isopentane mixture of mixture of

CbH ₁₂ methanol and water ammonia and water

⁰ CH.OH and HgO HH, and HgO

State of the natural gas temperature in ⁰ C 160 ° -82 ° -90 °

Print in ata »1 40 30

Volume in mV day 13,000 17,600. 16,900

O
cn III State of the "cold" m Temperature in ⁰ C -157 ° cn Coolant Pressure in ata. 1 cn Volume in m / day 17.300

co II state of the ^ heated "temperature in ⁰ C + 20 ° + 20 ° + 20 °

oo coolant pressure in ata »1 1 1

»Volume in mV day 21,700 13,600 7,500

Pressure in ata «1 1

Volume in mV day 21,700 13,600

-85 ° -95 °

1 1

12,500 7,000

Volume of I + II in m ⁵ / day Pall A Pall B Pall C

34,700 31,200 24,400

It is now assumed that the coolant is constantly between the place of production and the place of consumption is transported back and forth, i.e. in cold " State from the place of consumption to the place of production and in the "warmed up" state from the place of production to the place of consumption.

Im Pall A (when using isopentane as a coolant) 13 · 000 m of liquefied natural gas for Delivered to the place of consumption. The amount of "cold * * coolant, which has to be transported to the place of production is 17,300 nr, of which 13,000 m * in the container, in to which the liquefied natural gas was delivered, can be transported. Pur the difference of 4,300 nr "cold" coolant is a special container space for the transport from the place of use to the place of production necessary. For the transport of the "heated ·· coolant and the liquefied natural gas from the place of production to the place of consumption, there are 21,700 nr container space for the "heated" coolant and 13,000 nr for the liquefied natural gas. The total needed The container space is therefore 34,700 m; it should be noted, however, that no thermal insulation or Application of pressure when transporting the heated coolant are required.

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In case B (when using a mixture of methanol and water as a coolant) 17,600 m ^{5 of} liquefied natural gas are delivered to the place of consumption. The amount of "cold ^11" coolant that has to be transported to the place of production is 12,500 nr; since this is a volume less than 17,600 m, the coolant can be completely transported in the container in which the liquefied natural gas was delivered. Pur the transport For the transport of the "heated" coolant and the natural gas from the place of production to the place of consumption, 13,600 m of container space are required for the "heated" coolant and 17,600 nr for the liquefied natural gas. The total tank space required is therefore 31,200 m, but it should be noted that no thermal insulation or the use of pressure is required when transporting the "heated" coolant.

In case C (when using a mixture of

Ammonia and water as coolants) are 16,900 m Liquefied natural gas delivered to the place of consumption. The amount of "cold" coolant going to the place of production has to be transported is 7,000 m; since this is a volume less than 16,900 m, it can be completely be transported in the container in which the liquefied natural gas was delivered. for transportation

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of the "cold" coolant from the place of consumption to the place of production therefore no special container space is required. For the transport of • ♦ warmed "refrigerant and natural gas rom generation to point of consumption 7 * 500 m container space are used for" warmed "refrigerant and 16.900 nr needed for the liquefied natural gas. The total required tank space is accordingly it 24,400 number j to but out It should be pointed out that no thermal insulation or the application of pressure are required to transport the heated coolant.

From the above it can be seen that in terms of the required container space, Pall B is more favorable than Case A and Case C, in turn, are more favorable than Case B.

It should be noted that the said coolants are also used when storing methane or natural gas can be used for peak demand. During periods of low demand for natural gas or methane this can be liquefied by heat exchange with a "cold" coolant according to the invention. That Liquefied methane or natural gas can then be stored in suitable containers and at times of great demand Natural gas or methane converted into the gas state by heat exchange with the "heated" coolant will. The cooled-down coolant is then stored until another period of low demand for natural gas or

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Methane enters. Then the cold coolant becomes Liquefaction of a quantity of methane or natural gas is used, which is stored until there is a need for natural gas or methane rises again.

Claims

85TII 909883/0555

Claims (6)

8 MUNICH 9 I. ING. F. WtTKSTHOKF scuwkiükh.strasse «IiIPU ING. G. I-UI.8 "^ roH" 0, "1 C Π 1 7 /. fl DR.K.T.PKOHMANN I 0 U I / HO ll \ TICLBOBAM MIDIIIMI t PATKNTANWiLTE J <1 pbotkotfatbkt mCkcbbv 1A-30 995 claims 1.7 Methods of transporting gas, in particular Clay methane or natural gas, in the liquid state by cooling and liquefying the gas at the place of production, Transporting the liquefied gas in a container to the point of use, transferring the liquefied gas into the gaseous state by exchanging heat with a coolant at the point of use, introducing the cooled-down coolant into a storage container, transporting it to the place of production, where again gas is cooled and liquefied by heat exchange with the coolant, characterized in that that the coolant used is water mixed with at least one agent for lowering the freezing point. 2. The method according to claim 1, characterized in that the coolant is water in the Mixture used with ammonia. 3. The method according to claim 1, characterized in that the coolant used is water, mixed with at least one alcohol, preferably Methanol is used. 909883/0555 -V 4. The method according to claim 1-3, characterized in that the liquefied Gas in the container at a pressure greater than 1 atm. transported. 5. The method according to claim 1-4 thereby it indicates that the heated coolant is introduced into a container and preferably transported back to the place of consumption at atmospheric pressure or approximately atmospheric pressure. 6. The method according to claim 1-5, characterized in that the transferring of the liquefied gas in the gaseous state, the refrigerant is cooled down in the same Storage container transported from the place of consumption to the place of production, in which the liquefied gas from Place of production was delivered to place of consumption. 909883/0568