DE10009059A1 - Use of molecular sieve carbon for separating nitrogen from methane e.g. for purifying natural gas or biogas - Google Patents

Abstract

Molecular sieve carbon (I) is used for the large-scale separation of nitrogen from methane. Independent claims are also included for the following: (1) Molecular sieve carbon having: (a) a mean pore diameter of 0.1-1 nm; (b) equilibrium adsorption values for nitrogen, methane, carbon dioxide and ethylene, measured at 25 deg C and 0.1 MPa, of 3-15, 10-40, 30-90 and 30-90 Nl/kg respectively; and (c) adsorption parameters (times required to achieve half equilibrium adsorption value) for nitrogen, methane, carbon dioxide and ethylene, measured at 25 deg C and 0.1 MPa, of 0.01-10, 1-1000, 0.001-1 and 0.1-100 minutes respectively. (2) A process for recovering a methane-enriched gas from a mixture of methane and nitrogen, comprising contacting the mixture with (I) under pressure so that the nitrogen is selectively adsorbed and removed. (3) (I)-equipped apparatus for separating and purifying methane.

Description

The present invention relates to a new molecular sieve for the extraction of methane from gas mixtures, the methane as the main included. The present invention also relates to a new process for the separation and purification of methane under Ver application of the above-mentioned molecular sieve carbon and also on a pre direction equipped with the above-mentioned molecular sieve carbon, for the separation or purification of methane. In particular, the present invention a new technology for efficient extraction and tearing Securing methane from a gas mixture containing nitrogen and methane contains gas (hereinafter referred to as "nitrogen") and that Can contain carbon dioxide, ethylene and / or another gas Removal of components other than methane by adsorption.  

Underground natural gas, waste gases from anaerobic fermentation processes and waste gases from the fermentation of waste or industrial waste contains methane, which is flammable and is an excellent source of energy, as Main ingredient. However, these gas resources often contain alongside that Methane a large amount of non-flammable gases, such as nitrogen and coal di oxide. It is therefore essential to increase the methane content in these gases hen to obtain a gas with high combustion energy.

So far, various methods have been proposed to create a special one Extract component from exhaust gases, for example cryogenic distillation, Using membrane separation and pressure swing adsorption molecular sieve coal (see for example Japanese Laid-Open publications No. 216703/1983, 39304/1984, 159830/1983, 101541/1986, 284635/1990, 281096/1990, 127605/1991, 131317/1991, 151013/1991, 299356/1995 and 896/1997). However, none of these has proven to be sufficient Efficiently proven to produce methane on an industrial scale by separating the To obtain methane from nitrogen.

These known methods have the following disadvantages:

• 1. Cryogenic distillation, in which gases using their difference separating boiling points gives first nitrogen and then Me than because the boiling point of nitrogen is lower than that of methane. If the gas to be treated also contains carbon dioxide, remains The carbon dioxide sticks at the working temperature and can be a smooth Prevent the system from operating. The previous removal of the Kohlendi oxides leads to complex equipment on a large scale what is not economically preferable.
• 2. The membrane separation process and the pressure fluctuation adsorption pressure swing adsorption (PSA) method using a mole  molecular sieve charcoal has the advantage that it can be used without heating and cooling Room temperature can be carried out. The appliances have a fairly simple and compact structure. The PSA process will actually applied to methane from mixtures of methane and koh to separate out the dioxide.

When separating methane from nitrogen using the be Known process, however, it is difficult to achieve a high separation performance and high methane productivity.

The aim of the present invention is to describe those described above Solve problems with traditional methods and a new material and methods for efficiently recovering methane from exhaust gases to deliver.

The problem is solved by a specially designed molecular sieve carbon, which makes it possible to efficiently separate methane from a gas mixture which from methane and incombustible gases such as nitrogen and carbon dioxide stands.

The present invention relates to:

• a) a molecular sieve charcoal for use in large-scale extraction of methane from nitrogen in a gas mixture containing methane and Contains nitrogen;
• b) a molecular sieve according to (i), which is used to obtain a methanane enriched gas from a gas mixture that ent methane and nitrogen holds, is suitable by selectively adsorbing the nitrogen;  
• c) a molecular sieve coal according to (ii), the gas mixture in addition to Me than and nitrogen contains one to four constituents, which from the Group are selected from carbon dioxide, argon, ethylene and acid fabric consists;
• d) molecular sieve coal according to (i) to (iii), their adsorption times for the adsorption of half of the equilibrium adsorption amount of stick substance, methane, ethylene and carbon dioxide are required at 25 ° C and 0.1 MPa 0.01 to 10 minutes, 1 to 1000 minutes, 0.1 to 100 minutes or 0.001 to 1 minute;
• e) molecular sieve coal according to (i) to (iii), their adsorption times, which for the adsorption of half of the equilibrium adsorption amount of stick substance, methane, ethylene and carbon dioxide are required at 25 ° C and 0.1 MPa 0.1 to 5 minutes, 10 to 500 minutes, 1 to 50 minutes or 0.01 up to 0.5 minutes;
• f) molecular sieve coal according to (i) to (v), the same at 25 ° C and 0.1 MPa weight adsorption amounts from 3.0 to 15.0 normal liters / kg, 10.0 to 40.0 normal liters / kg, 30.0 to 90.0 normal liters / kg or 30.0 to 90.0 nor malliter / kg for nitrogen, methane, ethylene or carbon dioxide;
• g) molecular sieve coal according to (i) to (v), the same at 25 ° C and 0.1 MPa weight adsorption amounts from 6.0 to 11.0 normal liters / kg, 15.0 to 30.0 normal liters / kg, 35.0 to 80.0 normal liters / kg or 35.0 to 80.0 nor malliter / kg for nitrogen, methane, ethylene or carbon dioxide;
• h) molecular sieve coal according to (i) to (vii), in the form of pellets, granules lat, powder, fiber or honeycomb is present;  
• i) molecular sieve coal according to (i) to (viii), the middle micropores diameter of the molecular sieve carbon is in the range from 0.01 to 1.0 nm;
• j) molecular sieve carbon according to (i) to (viii), the middle micropores diameter of the molecular sieve carbon is in the range from 0.3 to 0.5 nm;
• k) molecular sieve carbon with the following physical properties:
  • a) Average micropore diameter: 0.1 to 1.0 nm
  • b) Equilibrium adsorption amount for the respective components at 25 ° C and 0.1 MPa:
    Nitrogen: 3.0 to 15.0 normal liters / kg
    Methane: 10.0 to 40.0 normal liters / kg
    Carbon dioxide: 30.0 to 90.0 normal liters / kg
    Ethylene 30.0 to 90.0 normal liters / kg;
  • c) Adsorption parameters for the respective components at 25 ° C and 0.1 MPa:
    Nitrogen: 0.01 to 10.0 minutes methane: 1.0 to 1000.0 minutes carbon dioxide: 0.001 to 1.0 minutes ethylene 0.1 to 100.0 minutes;
• l) Use of a molecular sieve according to (i) to (xi) for the large technical separation of methane from nitrogen in a gas mixture, that contains methane and nitrogen;
• m) Process for obtaining a methane-enriched gas from egg gas mixture containing methane and nitrogen by contact  Bringing the gas mixture with the molecular sieve coal according to (i) to (xi) under pressure so that the nitrogen is selectively adsorbed and removed;
• n) Device for the separation and purification of methane with the Molecular sieve coal is equipped according to (i) to (xi).

The aim of the present invention is to describe those described above Solve problems with traditional methods and a new material and method for the efficient extraction of methane from exhaust gases in tech African scale to provide.

It has been found that the use of a specially designed molecule Carbon sieve enables methane to be efficiently extracted from a mixture of gases like separating methane, nitrogen and carbon dioxide, for example as Exhaust gas from anaerobic fermentation processes was obtained.

The present invention thus relates to a new molecular sieve le and on a process for the production of methane from exhaust gas mixtures, like natural gas from underground resources, exhaust gases from an anaerobic Fermentation process and exhaust gases from the fermentation of waste or industrial waste fall. The method of this invention for recovering methane is there characterized in that the methane-containing exhaust gases under pressure in contact with the new molecular sieve carbon so that the nitrogen and selectively removing the carbon dioxide by adsorption, the methane-enriched gas continuously extracted as an outflowing gas becomes.

In the present invention, exhaust gases (hereinafter referred to as "raw Substance gas (s) "referred to) as natural gas from underground resources, exhaust gases from an anaerobic fermentation process and waste gases from the fermentation of Garbage or industrial waste, which is a mixture of methane  (as the main component) and incombustible gases such as nitrogen and Koh Lendioxide acts, initially under pressure with the molecular sieve the present invention (hereinafter referred to as "adsorption step "). The raw material gas that is available with the process of Invention can be treated, can stick in addition to methane substance or nitrogen and carbon dioxide or one to four of the gases carbon dioxide contain oxide, argon, ethylene and oxygen.

The molecular sieve carbon to be used in the present invention, the also "carbon molecular sieve", "molecular sieve carbon", "molecular sieve activated carbon" etc. is called, like activated carbon consists of microcrystalline carbon material. Therefore, their properties, e.g. B. elementary composition, chemical properties, adsorption selectivity towards polar moles cool etc., almost the same as activated carbon. The in the present inven However, molecular sieve carbon to be used has almost uniform Ultramicropores of no more than 1 nm (e.g. 0.3 to 0.5 nm) medium Micropore diameter, in particular 0.01 to 1.0 nm or preferably 0.05 to 0.8 nm or most preferably 0.1 to 0.6 nm middle micro pore diameter, and has molecular sieve properties.

For example, molecular sieve charcoal can be made according to the method disclosed in Japanese Patent Publication No. 18675/1977 of fenbt is. A hydrocarbon that can release carbon if it does pyrolyzed is added to coke, which contains volatile Has material of up to 5 wt .-%, and at the same time the coke is 1 to 60 min heated to 600 to 900 ° C for a long time. Fills up during this heat treatment the released carbon partially on the micropores of the coke and thus forms the molecular sieve coal made from coke. Molecular sieve coals can also be made according to the procedures described in Japanese  Patent Publication No. 37036/1974, in Japanese Disclosure No. 45914/1984, etc. are disclosed.

As the molecular sieve coal to be used in the present invention, those having the following physical properties are preferably used:

• a) average micropore diameter: 0.3 to 0.5 nm or alternatively 0.01 to 1.0 nm, most preferably 0.05 to 0.8 nm, most preferably 0.1 to 0.6 nm;
• b) Equilibrium adsorption amount (at 25 ° C and 0.1 MPa):
  The equilibrium adsorption amounts for each compound are as follows:
  Nitrogen: 3.0 to 15.0 normal liters / kg, preferably 5.0 to 12.0 normal liters / kg, most preferably 6.0 to 11.0 normal liters / kg;
  Methane: 10.0 to 40.0 normal liters / kg, preferably 12.0 to 35.0 normal liters / kg, most preferably 15.0 to 30.0 normal liters / kg;
  Carbon dioxide: 30.0 to 90.0 normal liters / kg, preferably 32.0 to 85.0 normal liters / kg, most preferably 35.0 to 80.0 normal liters / kg;
  Ethylene 30.0 to 90.0 normal liters / kg; preferably 32.0 to 85.0 normal liters / kg, most preferably 35.0 to 80.0 normal malliters / kg
• c) Adsorption parameters:
  The term "adsorption parameter" used here means a value which is determined as the time which is necessary for the adsorption of the respective gas component up to half of its equilibrium adsorption amount. The adsorption parameter for the respective compound at 25 ° C and 0.1 MPa is as follows:
  Nitrogen: 0.01 to 10.0 minutes, preferably 0.05 to 8.0 minutes, most preferably 0.1 to 5.0 minutes
  Methane: 1.0 to 1000.0 minutes, preferably 5.0 to 800.0 minutes, most preferably 10 to 500.0 minutes
  Carbon dioxide: 0.001 to 1.0 min, preferably 0.005 to 0.8 min, most preferably 0.01 to 0.5 min
  Ethylene 0.1 to 100.0 minutes, preferably 0.5 to 80.0 minutes, most preferably 1.0 to 50.0 minutes.

A molecular sieve coal with these physical properties can according to the methods described above by appropriate selection of ver driving conditions are established.

In the present invention, the molecular sieve carbon can be various Forms are available and used; these include pellet, granulate, Powder, fiber / textile or honeycomb form. Of these, the pellet and the Granular form to be preferred for molecular sieve coal. The pellets or Granules of molecular sieve carbon preferably have a diameter in the range from 0.1 mm to 4 mm, particularly preferably 0.2 mm to 3 mm, most preferably 0.3 mm to 2 mm. Pellet size too small or granules is technically not preferable because they become larger Loss of pressure. The filling density of the pellets is preferably in Range from 500 g / l to 900 g / l, particularly preferably from 600 g / l to  800 g / l and very particularly preferably from 650 g / l to 750 g / l. One too Rings filling density is not preferable as it leads to a low gasad sorption capacity per column volume and also to the destruction of the Adsorbent in the operating state due to a low mechanical solids activity of the adsorbent.

The raw material gas to be treated usually contains about 40 to about 90% by volume Methane and about 5 to about 50 volume percent nitrogen and about 1 to about 50 vol .-% carbon dioxide. It can also contain 0.01 to 5% by volume Contain ethane, ethylene, oxygen and argon. In the present Invention, the raw material gas is in contact with the molecular sieve coal brings so that nitrogen, carbon dioxide and oxygen through selective ad sorption are preferably removed. However, methane does not become selective adsorbed. The other gases, for example argon and ethylene, can are also adsorbed and removed. If the concentrations of this Gases are low, for example 0.01 to 5 vol .-%, the methane can be carried out under conditions in which the Gases other than nitrogen cannot be adsorbed and removed.

Furthermore, the raw material gas sometimes contains small amounts of sulfur bonds such as hydrogen sulfide, methyl sulfide, methyl disulfide, mercap tane derivatives, sulfur dioxide, etc., nitrogen oxides, such as nitrogen dioxide, so like high-boiling organic compounds, like oil mist. The concentration These impurities are usually from about 0.01 ppm to 1 vol%.

Preferably, these contaminants should be pre-methane purification step, from which raw material gas is removed, as this contains impurities attitudes, although they are only available in small quantities, by the Molecular sieve charcoal adsorbed and accumulated in the same Can reduce methane separation capacity of molecular sieve coal.  

Once these sulfur compounds, nitrogen oxides and oil mist on the Molecular sieves are adsorbed, both their desorption and the Regeneration of molecular sieve coal is very difficult to carry out ren.

Pre-filters are available to remove these contaminants in advance with conventional desulfurization agents, adsorbents, Activated carbon and activated carbon, zinc oxide or iron class catalysts are filled. Examples of the fillers are SHIRASAGI G2x, SHIRASAGI GS1x, SHIRASAGI GS2x, SHIRASAGI SRCx, SHIRASAGI NCC, NIONON 202 HR, NIONON 202 SN and NIONON 202P (all manufactured by Takeda Che mical Industries, Ltd.).

The adsorption process takes place under pressure, preferably under one Pressure from about 0.3 to 5.0 MPa. The raw material gas, e.g. B. natural gas from Unterir resources, waste gases from an anaerobic fermentation process and waste gases from the fermentation of waste or industrial waste, the methane as Main ingredient is usually compressed to 0.5 to 3.5 MPa. Preferably, moisture should be present in the gas during this Compression step are condensed and removed. It's economical the adsorption process under a pressure within this range perform.

The time required for the adsorption process is 1 to 10 minutes before preferably 2 to 5 min. At this step, the flow rate becomes high speed of the supplied gas advantageously from a range of about 10 to about 200 times the volume of the adsorbent in the column (SV = 10 to 200 / h), preferably 20 to 150 times (SV = 20 to 150 / h), be particularly preferably 40 to 120 times (SV = 40 to 120 / h). A high methane yield is achieved at a flow rate from reached about 60 to 100 times the volume of the adsorbent in the column.  

The temperature to be used during the adsorption is initially one ordinary temperature, for example about 20 to about 30 ° C. Although the Temperature due to the heat generated in the adsorption reaction gradually increases, special temperature control is not necessary. The molecular sieve carbon can be regenerated for reuse by the gases adsorbed thereon, such as nitrogen, carbon di oxide, ethylene, oxygen, argon and ethane, according to known procedures Removed, or it can become brisk using the procedure below be neriert, which is adopted in the present invention.

The present invention will be described with reference to the following drawing tion explained in more detail.

Fig. 1 shows a schematic diagram of a typical methane purification system according to the method of the present invention together with the flow of the gas.

In Fig. 1 an apparatus is shown which is equipped with three adsorption towers A, B and C. However, the number of towers can be increased or decreased if necessary. Each adsorption tower is filled with an adsorbent, molecular sieve coal.

The raw material gas, e.g. B. an exhaust gas containing methane, nitrogen and carbon dioxide as main components, tower A is supplied via gas supply line 1 and brought into contact with the adsorbent in the tower, the nitrogen and carbon dioxide being adsorbed on the adsorbent. In this adsorption step, the largest part, for example at least 90% by volume, of the nitrogen and carbon dioxide contained in the raw material gas can be adsorbed. Although methane is also partially adsorbed, the amount adsorbed can be kept below 1% by volume.

The gas removed from the adsorption tower, ie the product gas, consists mainly of methane and contains methane and only traces of the other gases. The product gas is removed via the product line 2 , which is located above the adsorption tower, and is preferably stored in a product buffer tank in order to avoid temporal fluctuations in the pressure and the flow rate of the product gas.

Then the desorption of nitrogen and of takes place in adsorption tower A. Carbon dioxide from the adsorbent. At the same time, the raw material gas is selected rend the time in which the desorption process in the adsorption tower Is underway, the raw material gas adsorption tower C is fed, where the same Ad sorption operations are carried out as described above. There the adsorption tower is usually kept under pressure in the adsorption step partial desorption of the adsorbed onto the adsorbent Gas components are made by releasing the pressure until it Ambient pressure reached.

When the internal pressure of the adsorption tower has been reduced to a normal pressure, the adsorption tower is operated by means of a suction pump, e.g. B. a vacuum pump, evacuated to an internal pressure of about 0.005 to about 0.07 MPa. This process leads to a sufficient desorption of the components adsorbed on the adsorbent. The desorbed gases are discharged via the exhaust pipe 3 . The desorption temperature can be determined depending on the desorption rate required and the amount of material desorbed, but is generally in the range from about -5 ° C to about 30 ° C.

Alternatively, after complete removal of the product gas containing methane as the main component, the desorption can also be carried out from the product line 2 at the top of the adsorption tower by letting the desorbed gas, which contains nitrogen and carbon dioxide as the main components, escape recovered via the exhaust pipe 3 at the bottom of the same adsorption tower.

To achieve more thorough desorption, the top of the Adsorption tower ago a purge gas can be introduced. A gas that as Purge gas can be used, which is mainly made of methane hende. It is advantageous to add a small part of the product gas as a purge gas use.

The product gas thus obtained consists mainly of methane and contains Nitrogen and carbon dioxide in very low concentrations, but in the we substantial no oxygen and no argon. That means the Most of the product gas is flammable and that the content of un flammable components, such as nitrogen or carbon dioxide, very strong is induced. Accordingly, this has been done according to the method of the present invention product gas obtained has a high content of combustion energy and can be used as a raw material gas for the production of artificial natural gas etc. be applied.

When the desorption step is finished, the adsorption tower A turns on closing as a preparatory step for the next adsorption ter pressure. In this step, the raw material gas is preferred used to pressurize the tower again. Alternatively a pressure equalization process can also be used if necessary is agile. In this process, two tanks, one of which is the Adsorption step has ended and the other be the desorption step has ended, joined together, and the gas in the former tower is in transfer the latter so that the loss of gas material is avoided becomes. This step can be completed in a short time (e.g. 1 to 10 seconds) his.  

Examples example 1

100 parts by weight of carbon powder, of which 100% by weight has a particle size of has not been more than 0.05 mm in a rotary kiln in an air stream treated with oxygen at 250 ° C. until its oxygen content is 10% by weight reached, and then with 25 parts by weight of hard pitch and 15 parts by weight Coal tar mixed and kneaded while adding water to the mixture was given. The outer wall of the oven was heated to 80 ° C to a to ensure homogeneous mixing. The resulting mixture was put into an extruder and into pellets with a diameter molded of 2.0 mm. The pellets thus obtained were placed in a rotary kiln given and heated in the absence of air. The temperature grew gradually increased to a final temperature of 800 ° C was reached. Then the product was consecutively for 30 minutes long with steam supplied to the nitrogen gas stream, and then catch for 20 minutes with a mixture of benzene and furfuryl alcohol (50/50 w / w), which the nitrogen gas flow at a rate of 100 g / normal cubic meter was treated. Finally was the product under a stream of pure nitrogen to normal temp cooled down.

Every small part of the products obtained as described above became one Subjected to series of tests to determine the physical properties check, it became molecular sieve charcoal (trade name: "Molsievon 3K Type M-183 ", Takeda Chemical Industries, Ltd.) with the following physika preserved properties and ver in the following working example turns.  

The physical properties of the molecular sieve carbon used were as follows:
average micropore size: 0.41 nm
Equilibrium adsorption amount (at 25 ° C and 0.1 MPa):
Methane: 5-20.3 normal liters / kg
Nitrogen: 8.1 normal liters / kg
Carbon dioxide: 40.1 normal liters / kg
Ethylene 47.5 normal liters / kg;
Adsorption parameters (at 25 ° C and 0.1 MPa):
Methane: 21.19 min nitrogen: 0.29 min carbon dioxide: 0.025 min ethylene 2.01 min

Example 2

In the experiment, a system with three adsorption towers as shown in Fig. 1 was used. All adsorption towers had similar structures and were filled with molecular sieve coal ("Molsie von 3K Type M-183", a trade name of Takeda Chemical Industries, Ltd.). The adsorbent was packed as close as possible using a vibrator to prevent the adsorbent particles from moving or trickling.

As the raw material gas to be processed, a gas mixture was used in the one on the left Column shown in Table 1 used with which the Exhaust gas from an anaerobic fermentation process should be simulated.  

Adsorption step

The raw material gas was fed through the feed pipe 1 , which is located at the lower part of the adsorption tower, to the adsorption tower at 25 ° C. under a pressure of 0.8 MPa with a flow rate of about 0.31 m ³ / h (SV = 50 / h) A fed and brought into contact with the adsorbent, and then the product gas was led out of the tower via the product tube 2 (with an exit speed of 0.16 m ³ / h, treatment time 3 min). As a result, a methane-enriched product gas was obtained with the composition shown in the middle column of Table 1.

Desorption step

In this step, the supply of the raw material gas was interrupted, and the gas inside the adsorption tower was discharged through the exhaust pipe 3 by means of the residual pressure. The tower was then evacuated to 0.013 MPa using a vacuum pump to detach and recover the gases adsorbed on the molecular sieve carbon. During this operation, the temperature at the bottom of the adsorption tower dropped to 15 ° C. The recovered gas thus obtained had the composition shown in the right column of Table 1. In this experiment, the total yield of methane was 76%.

Recompression step

In order to proceed to the next adsorption step, part of the Pro Duct gas via the gas supply line at the bottom of the tower to the adsorpti onsturm returned until the pressure inside the tower is 0.8 MPa was enough.  

Table 1

The processes described above, ie the adsorption, desorption and recompression, are to be carried out in succession in the three adsorption towers. The sequence of the operations carried out in each individual tower is, for example, as follows:
Adsorption tower A: adsorption - desorption - recompression
Adsorption tower B: desorption - recompression - adsorption
Adsorption tower C: recompression - adsorption - desorption.

As described above, the present invention provides a new material and methods for efficiently obtaining a methane enriched Ga ses ready that only extremely small amounts of contaminants, eg. B. Contains nitrogen, carbon dioxide, etc. from a gas mixture, for example Natural gas from underground resources, waste gases from anaerobic fermentation process and exhaust gases from the fermentation of waste or industrial waste len. These gas mixtures generally contain methane as the main component component, which, however, at the same time considerably with inert gases such as nitrogen and Carbon dioxide is contaminated.  

The product gas thus obtained consists mainly of methane and contains only minor amounts of non-combustible gases such as nitrogen and Carbon dioxide, but essentially no oxygen and no argon. Accordingly, the product gas has a high content of burning energy and can be used as a raw material gas for the production of artificial Natural gas, etc. can be used.

In addition, the method according to the present invention has the advantage that it is at normal temperatures without additional heating or cooling can be done and that it is in a simply constructed facility can be carried out so that it is worthwhile to resemble existing plants of a smaller size.

Therefore, the method according to the present invention is excellent regarding safety and industrial applicability.

Brief comments on the drawing Fig. 1

Fig. 1 shows a schematic diagram of a typical process flow according to the present invention using three adsorption towers.

Explanations of the symbols

A, B, C adsorption towers

1

Raw material gas supply line

2nd

Product gas line

3rd

Exhaust pipe

Claims (14)

1. Molecular sieve coal for use in large-scale extraction tion of methane from nitrogen in a gas mixture, the methane and contains nitrogen. 2. molecular sieve coal according to claim 1, which is used to obtain a me than enriched gas from a gas mixture containing methane and Contains nitrogen is suitable by selectively ad sorbed. 3. molecular sieve coal according to claim 2, wherein the gas mixture in addition Methane and nitrogen still contains one to four components are selected from the group consisting of carbon dioxide, argon, ethyl len and oxygen exists. 4. molecular sieve coal according to any one of claims 1 to 3, the ad sorption times for the adsorption of half the equilibrium Adsorption amount of nitrogen, methane, ethylene and carbon dioxide are required at 25 ° C and 0.1 MPa 0.01 to 10 minutes, 1 to 1000 minutes, 0.1 to 100 minutes or 0.001 to 1 minute. 5. molecular sieve coal according to any one of claims 1 to 3, the ad sorption times for the adsorption of half the equilibrium Adsorption amount of nitrogen, methane, ethylene and carbon dioxide are required at 25 ° C and 0.1 MPa 0.1 to 5 minutes, 10 to 500 minutes, 1 to 50 minutes or 0.01 to 0.5 minutes.   6. molecular sieve coal according to any one of claims 1 to 5, which at 25 ° C. and 0.1 MPa equilibrium adsorption amounts from 3.0 to 15.0 nor malliter / kg, 10.0 to 40.0 normal liters / kg, 30.0 to 90.0 normal liters / kg or 30.0 to 90.0 normal liters / kg for nitrogen, methane, ethylene or Has carbon dioxide. 7. molecular sieve coal according to any one of claims 1 to 5, which at 25 ° C. and 0.1 MPa equilibrium adsorption amounts from 6.0 to 11.0 nor malliter / kg, 15.0 to 30.0 normal liters / kg, 35.0 to 80.0 normal liters / kg or 35.0 to 80.0 normal liters / kg for nitrogen, methane, ethylene or Has carbon dioxide. 8. molecular sieve coal according to any one of claims 1 to 7, which in the form of pellets, granules, powder, fibers or honeycombs. 9. molecular sieve coal according to any one of claims 1 to 8, wherein the average micropore diameter of molecular sieve carbon in the range from 0.01 to 1.0 nm. 10. molecular sieve coal according to any one of claims 1 to 8, wherein the average micropore diameter of molecular sieve carbon in the range from 0.3 to 0.5 nm. 11. Molecular sieve carbon with the following physical properties:

• a) Average micropore diameter: 0.1 to 1.0 nm
• b) Equilibrium adsorption amount for the respective components at 25 ° C and 0.1 MPa:
  Nitrogen: 3.0 to 15.0 normal liters / kg
  Methane: 10.0 to 40.0 normal liters / kg
  Carbon dioxide: 30.0 to 90.0 normal liters / kg
  Ethylene 30.0 to 90.0 normal liters / kg;
• c) Adsorption parameters for the respective components at 25 ° C and 0.1 MPa:
  Nitrogen: 0.01 to 10.0 minutes
  Methane: 1.0 to 1000.0 minutes
  Carbon dioxide: 0.001 to 1.0 minutes ethylene 0.1 to 100.0 minutes.

12. Use of a molecular sieve coal according to one of claims 1 to 11 for the large-scale separation of methane from nitrogen in a gas mixture containing methane and nitrogen. 13. Process for obtaining a methane-enriched gas from a gas mixture containing methane and nitrogen by in- Bringing the gas mixture into contact with the molecular sieve coal according to one of claims 1 to 11 under pressure, so the nitrogen se is selectively adsorbed and removed. 14. Device for the separation and purification of methane with the Molecular sieve coal according to one of claims 1 to 11 is.