JP6093519B2 - Method and apparatus for separating nitrogen from nitrogen-containing hydrocarbon gas - Google Patents

Description

The present invention relates to a method and apparatus for separating nitrogen from nitrogen-containing hydrocarbon gas, and more particularly, nitrogen-containing hydrocarbon gas, which includes methane such as nitrogen-containing methane, natural gas, city gas, or digestion gas as a main component. The present invention relates to a method for separating nitrogen from hydrocarbon gas and a nitrogen separation apparatus. More specifically, methane, natural gas, city gas or digestion gas containing nitrogen is used as the gas to be treated, and the gas to be treated is supplied to and passed through a column filled with an adsorbent. The present invention relates to a nitrogen separation method and a nitrogen separation apparatus for obtaining a CH ₄ enriched gas from a contained CH ₄ —N ₂ mixed gas.

  As a gas separation method for removing nitrogen contained in methane, natural gas, city gas, digestion gas, etc., for example, pressure using an adsorbent as described in Patent Documents 1 to 3 or Non-Patent Document 1 Swing adsorption separation (PSA) is known.

In Patent Document 1, mordenite-type zeolite (Na-mordenite-type zeolite, part of Na ions is substituted with Ag ions) is used to separate CH ₄ and N ₂ mixed gas due to the difference in breakthrough time. Have been described.
In Patent Document 2, a clinoptilolite-type zeolite having a CaO / Al ₂ O ₃ molar ratio of 0.3-0.75 and a normal butane adsorption index ratio of 3 or more adsorbs N ₂ , and CH ₄ Is not adsorbed.

Patent Document 3 describes an adsorptive separation agent comprising a clinoptilolite-type zeolite having a CaO / Al ₂ O ₃ molar ratio of 0.4 to 0.75 as the amount of calcium ions contained as cations, Thereby, it is said that nitrogen gas in methane gas can be effectively removed.
Non-Patent Document 1 describes a material in which various ions are ion-exchanged with clinoptilolite for separation of CH ₄ —N ₂ , and includes a sample in which natural clinoptilolite is exchanged with Sr. .

Japanese Patent No. 4602202 Japanese Patent Publication No. 6-2575 Japanese Patent Publication No. 6-85870

Ind. Eng. Chem. Res., 44 (2005) p.5184-5192

An object of the present invention is to provide a method and a nitrogen separation apparatus for effectively separating nitrogen from a nitrogen-containing hydrocarbon gas using a synthetic clinoptilolite having strontium at an ion exchange site.
More particularly, the present invention is a gas separation method and nitrogen separation device to obtain a CH ₄ concentration gas using synthetic clinoptilolite having a strontium ion-exchange sites of clinoptilolite from CH ₄ -N ₂ mixture gas Is intended to provide.

As a result of intensive studies in view of the above problems, the present inventors have found that synthetic clinoptilolite (hereinafter referred to as “strontium exchanged clinoptilolite” or “strontium” having strontium at the ion exchange site as an adsorbent for nitrogen separation. The present inventors have found a method and a nitrogen separation apparatus that can efficiently separate nitrogen from a nitrogen-containing hydrocarbon gas using “ion exchange clinoptilolite”.
That is, the present invention relates to a method for separating nitrogen from a hydrocarbon gas containing nitrogen and containing methane as a main component, and a nitrogen separator, characterized by using an adsorbent for nitrogen separation comprising strontium ion-exchanged clinoptilolite. is there.

The present invention relates to a method for separating nitrogen from hydrocarbon gas containing nitrogen and containing methane as a main component, characterized by using a nitrogen separating adsorbent comprising synthetic clinoptilolite having strontium at an ion exchange site Device.
That is, the present invention is a method for separating nitrogen from a hydrocarbon gas containing nitrogen and containing methane as a main component, and an apparatus therefor. A nitrogen separation adsorbent composed of strontium ion-exchanged clinoptilolite is used as the nitrogen separation adsorbent, and the nitrogen-containing hydrocarbon gas is processed through the nitrogen separation adsorbent.

In the method and apparatus for separating nitrogen from hydrocarbon gas containing nitrogen and containing methane as a main component according to the present invention, the nitrogen separating adsorbent comprising synthetic clinoptilolite having strontium at the ion exchange site is a molded body. A nitrogen separation method and a nitrogen separation apparatus from hydrocarbon gas containing nitrogen and containing methane as a main component, characterized in that
That is, the present invention relates to a nitrogen separation method and a nitrogen separation apparatus from hydrocarbon gas containing nitrogen and containing methane as a main component, and the nitrogen separation adsorbent comprising synthetic clinoptilolite having strontium at the ion exchange site, It can be configured as a molded body.

  In the present invention, examples of the hydrocarbon gas containing nitrogen and containing methane as a main component include any one or more of methane, natural gas, city gas and digestion gas containing nitrogen. The present invention is not limited to these exemplified gases, and any hydrocarbon gas containing nitrogen and containing methane as a main component can be used. The gas to be separated has a methane concentration of 60 to 99 vol% as a main component and a nitrogen concentration in the range of 40 to 1 vol%.

  As the separation method, a PSA (Pressure Swing Adsorption) method, a TSA (Temperature Swing Adsorption) method, a method combining these, and the like can be used. The adsorption pressure and temperature and the desorption pressure and temperature can be set according to the characteristics of the adsorbent. In particular, the adsorption temperature is preferably selected in the range from -162 ° C, which is the boiling point of natural gas, to about 40 ° C, which is near the room temperature, considering that natural gas is usually stored in a liquefied state.

  In the present invention, the nitrogen separation adsorbent comprising synthetic clinoptilolite having strontium at the ion exchange site is also configured and used as a nitrogen separation apparatus. This nitrogen separator is configured by filling a nitrogen separation adsorbent in a container such as an adsorption tower, and by passing a hydrocarbon gas containing nitrogen and containing methane as a main component in the nitrogen separation adsorbent. used. That is, a hydrocarbon gas containing nitrogen and containing methane as a main component is introduced from one side of a vessel such as an adsorption tower and passed through the nitrogen separation adsorbent, so that nitrogen is selectively used for the nitrogen separation adsorbent. Adsorb to. Thus, nitrogen is adsorbed and separated, and the hydrocarbon gas mainly composed of methane is taken out from the other side of the container.

<About strontium exchange clinoptilolite>
The strontium exchanged clinoptilolite used in the method and apparatus of the present invention is a synthetic clinoptilolite. Clinoptilolite is a naturally occurring zeolite. However, when clinoptilolite is naturally produced clinoptilolite (hereinafter, natural clinoptilolite), the amount of nitrogen adsorbed is low.

  The strontium exchanged clinoptilolite used in the method and apparatus of the present invention has strontium at the ion exchange site. By having strontium at the ion exchange site, the adsorption characteristic of nitrogen is improved.

  The greater the amount of strontium, the better the nitrogen adsorption properties. Therefore, the ratio of strontium in the ion exchange site of strontium exchanged clinoptilolite (hereinafter referred to as “strontium exchange rate”) is preferably at least 35 mol% with respect to the amount of ion exchange sites of clinoptilolite. More preferably, it is at least 40 mol%, more preferably at least 65 mol%, even more preferably at least 70 mol%, and particularly preferably at least 75 mol%.

  Examples of ion species other than strontium present at the ion exchange site include alkali metal ions such as sodium (Na) and potassium (K), and alkaline earth metal ions such as magnesium (Mg) and calcium (Ca). .

The SiO ₂ / Al ₂ O ₃ molar ratio of the strontium exchanged clinoptilolite used in the method and apparatus of the present invention is not particularly limited. Examples of the molar ratio of SiO ₂ / Al ₂ O ₃ include less than 10 (Si / Al atomic ratio of less than 5).

  The strontium exchanged clinoptilolite used in the method and apparatus of the present invention preferably has a pore volume in the range of a pore diameter of 3 to 10,000 nm of 0.5 ml / g or more, and 0.7 ml / g or more. More preferably, it is more preferably 0.8 ml / g or more. When the pore volume in the pore diameter range of 3 to 10,000 nm is 0.5 ml / g or more, the nitrogen adsorption amount tends to be high.

  Here, the strontium exchanged clinoptilolite used in the method and apparatus of the present invention consists of secondary particles in which primary particles are aggregated. Therefore, a pore volume with a pore diameter of 3 to 10,000 nm is a pore formed between primary particles, and a pore volume with a pore diameter exceeding 10,000 nm is formed between secondary particles. It is a void between powder particles.

  The strontium exchange clinoptilolite used in the method and apparatus of the present invention preferably has an average pore diameter of 200 nm or more, more preferably 400 nm or more. When the average pore diameter is 200 nm or more, moderate filling properties and strength are obtained. Thereby, the strontium exchange clinoptilolite used for the method of this invention tends to become the powder excellent in operativity.

  The adsorbent for nitrogen separation composed of synthetic clinoptilolite having strontium at the ion exchange site used in the method and apparatus of the present invention can be configured as a molded body. Examples of the shape of the formed body include a columnar shape, a spherical shape, a three-leaf shape, a ring shape, a honeycomb shape, and a film shape. In the case of forming a molded body, the type of binder contained in the molded body can be appropriately selected, and examples thereof include clay minerals and inorganic binders. Further, it may contain a molding aid in combination with the binder. The molding aid is used to improve moldability when producing a molded body, and examples thereof include organic molding aids. When used as a separating agent, heat dehydration is performed.

  According to the method and apparatus for separating nitrogen from the nitrogen-containing hydrocarbon gas of the present invention, nitrogen in the nitrogen-containing hydrocarbon gas can be maintained for a longer time than the conventional one. Nitrogen can be separated and removed.

It is a figure explaining the experiment apparatus used in Experimental Examples 1-2, and its operation. It is a figure which shows the result of Experimental example 1. FIG. It is a figure which shows the result of Experimental example 2. It is a figure explaining the experimental apparatus used in Experimental Examples 3-10, and its operation. It is a figure which shows the result of Experimental example 3-10. It is a figure explaining the experiment apparatus used in Experimental example 11, and its operation.

  Hereinafter, the present invention will be described in more detail based on experimental examples relating to selective adsorption characteristics of nitrogen in methane.

<Experimental equipment, operation>
FIG. 1 is a diagram illustrating the experimental apparatus used in Experimental Examples 1 and 2 and the operation thereof. As shown in FIG. 1, an adsorbent filling container 11 is arranged. In FIG. 1, the adsorbent for nitrogen separation is filled in the portion indicated as “adsorbent test sample”. The adsorbent test sample (adsorbent for nitrogen separation) is arranged in layers between the upper and lower perforated plates.
A conduit 2 for supplying methane gas containing nitrogen (N ₂ ) as a raw material gas is connected to the test gas supply side to the nitrogen separation adsorbent filling container 11. That is, the test gas conduit 1 provided with a flow rate regulator (MFC) and an on-off valve V (1) is disposed on the raw material gas supply side to the nitrogen separation adsorbent filling container 11.
In this experimental apparatus, the experiment can be carried out through steps 1 → procedure 2 → procedure 3 by operating on-off valves (= valves) V (1) to V (8).

<1. Step 1>
Procedure 1 is a step of evacuating the system. Among V (1) to V (8), V (1), V (6) and V (8) are closed, and V (2) to V (5) and V (7) are opened. Then, the vacuum pump arranged via the branch pipe 8 from the conduit 6 is operated. As a result, the inside of the experimental apparatus system is evacuated.

<2. Step 2>
After evacuating the inside of the experimental apparatus system, the procedure proceeds to procedure 2. Procedure 2 is a step of introducing the raw material gas into the adsorbent filling container 11 and shifting the evacuated system from a vacuum and a reduced pressure state to a normal pressure state. Among V (1) to V (8), V (1) to V (4) are opened, and V (5) to V (8) are closed.
At this time, the raw material gas is introduced into the adsorbent filling container 11 from the conduit 1 through the conduit 2 and V (3), and the raw material gas is also introduced into the bypass line 5 together. Since V (5) to V (8) are closed, the raw material gas is introduced into the conduits 6 to 8.

<3. Step 3>
In the procedure 3, the raw material gas is introduced into the adsorbent-filled container 11 and the step of the procedure 2 is performed in which the inside of the evacuated system is shifted from the vacuum and the reduced pressure state to the normal pressure state, and then the procedure 3 is performed. The procedure 3 is a step of introducing the raw material gas into the adsorbent filling container 11 and performing nitrogen adsorption, and observing the adsorption tendency over time. The procedure has shifted to the normal pressure state in step 2, and the normal pressure state is maintained in step 3 and is continued.

  Among V (1) to V (8), V (1), V (3), V (5) to V (6), V (8) are opened, and V (2), V (4), V (7) is closed. At this time, the raw material gas is introduced into the container 11 from the conduit 1 through the conduit 2 and V (3), and the raw material gas is also introduced into the bypass line 4 together.

Using a synthetic clinoptilolite (hereinafter referred to as calcium exchange clinoptilolite) adsorbed with calcium as a comparative example, using a strontium exchanged clinoptilolite adsorbent as an example, using the experimental apparatus shown in FIG. The breakthrough gas composition was measured. A gas having a CH ₄ concentration of 90 vol% and an N ₂ concentration of 10 vol% was used as the input gas. Hereinafter, comparative examples and examples will be sequentially described. In FIG. 1, “Summary of test using source gas (incoming gas) with CH ₄ concentration of 90 vol% and N ₂ concentration of 10 vol%” is displayed at the bottom.

<Experimental Example 1: Comparative Example>
The calcium exchange clinoptilolite adsorbent was sized to a size of 1.0 to 1.4 mm in diameter and filled in the container 11. The gas entering the filling container 11 [CH ₄ concentration 90 volume% (vol%), N ₂ concentration 10 volume% (vol%)] was introduced into “calcium exchange clinoptilolite”, and the breakthrough gas composition was measured. .

This test was performed under the condition of a superficial velocity of 90 (/ h) and changing the space velocity. FIG. 2 shows the results. In FIG. 2, the horizontal axis represents the elapsed time from the gas introduction, and the vertical axis represents the CH ₄ concentration. FIG. 2 shows the results at the space velocity SV = 90, 180, 360, 720 (/ h).

The following facts are clear from the results of FIG.
(A) When the space velocity SV is 720 (see the line (a) in FIG. 2), the CH ₄ concentration peaks at about 94.1 vol%, and the breakthrough time is only 2 seconds.
(B) When the space velocity SV is 360 (see line (b) in FIG. 2), the CH ₄ concentration peaks at about 96.0 vol%, and the breakthrough time is only 3 seconds.
(C) When the space velocity SV is 180 (see line (c) in FIG. 2), the CH ₄ concentration peaks at about 96.9 vol%, and the breakthrough time is about 6 seconds.
(D) When the space velocity SV is 90 (see line (d) in FIG. 2), the CH ₄ concentration peaks at about 97.0 vol%, and the breakthrough time becomes as long as 10 seconds. That is, in FIG. 1, the CH ₄ concentration of 97.0 vol% measured by the mass spectrometer was held for about 10 seconds.

As such, the peak of CH ₄ concentration is 97.0 vol% and the breakthrough time is as long as 10 seconds, which is useful as it is, but the peak of CH ₄ concentration is limited to 97.0 vol%, The time is 10 seconds, which is the limit. A CH ₄ concentration peak of 97.0 vol% means that 3 vol% nitrogen remains and is still included, and that the breakthrough time is 10 seconds indicates that the CH ₄ concentration reaches 97.0 vol%. Although the nitrogen separation operation time has been improved by that amount, the useful nitrogen separation operation period is still short with such a breakthrough time or breakthrough maintenance time.

<Experimental example 2: Example>
The strontium exchanged clinoptilolite adsorbent was sized to a size of 1.0 to 1.4 mm in diameter and filled into the container 11. The strontium ion exchange rate of this adsorbent was 82.1%. The gas entering the filling container 11 [CH ₄ concentration 90 vol% (vol%), N ₂ concentration 10 vol% (vol%)] was introduced into the strontium exchange clinoptilolite, and the breakthrough gas composition was measured.

This test was performed by changing the space velocity of the gas to be processed under the condition of the superficial velocity of 90 (h). FIG. 3 shows the result. In FIG. 3, the horizontal axis represents the elapsed time from the time of gas introduction, the vertical axis represents the CH ₄ concentration, and the left and right vertical axes have the same scale. Further, in FIG. 3, the results at space velocities SV = 90, 180, 360, 720h ⁻¹ are shown.

The following facts are clear from the results of FIG.
(A) When the space velocity SV is 720 (see the line (a) in FIG. 2), the CH ₄ concentration peaks at about 96.7%, and the breakthrough time is only 3 seconds.
(B) When the space velocity SV is 360 (see line (b) in FIG. 2), the CH ₄ concentration peaks at about 98.3%, and the breakthrough time is only 6 seconds.
(C) When the space velocity SV is 180 (see the line (c) in FIG. 2), the CH ₄ concentration peaks at about 99.0%, and the breakthrough time is considerably long, but is about 16 seconds.
(D) When the space velocity SV is 90 (see the line (d) in FIG. 2), the CH ₄ concentration peaks at about 99.0%, and the breakthrough time is very long as 30 seconds. In FIG. 1, the CH ₄ concentration of 99.0% measured with the mass spectrometer was maintained for a long time of about 30 seconds.

(Evaluation of adsorption and separation characteristics of nitrogen by chromatography)
FIG. 4 is an experimental apparatus diagram used in Experimental Examples 3 to 10. The adsorbent for nitrogen separation was shaped and sized to 0.35 to 0.5 mm, and about 4.5 ml was dehydrated in air at 500 ° C. for 1.5 hours, and then maintained at 25 ° C., an inner diameter of 4.35 mm × length A 30 cm long stainless steel column was packed while flowing helium (purity 99.999% or more). Helium (purity 99.999% or more) as a carrier gas is passed through the column at a flow rate of 50 Nml / min, and the flow of the hexagonal gas sampler is switched to enter the gas (CH ₄ concentration 90% by volume, N ₂ concentration 10% by volume). ) Is injected into the column for 1 cc, nitrogen and methane in the outlet gas are detected by a TCD detector, and the retention time of nitrogen and methane is analyzed from the obtained chromatogram, and the difference between the retention times of nitrogen and methane is calculated. did.

<Experimental Example 3: Example>
Using strontium exchanged clinoptilolite with a strontium exchange rate of 70.1%, the difference in retention time between nitrogen and methane was evaluated. Table 1 shows the difference in retention time between nitrogen and methane at 25 ° C.

<Experimental Example 4: Example>
Using strontium exchange clinoptilolite having a strontium exchange rate of 79.7%, the difference in retention time between nitrogen and methane was evaluated. Table 1 shows the difference in retention time between nitrogen and methane at 25 ° C.

<Experimental Example 5: Example>
Using the same strontium exchanged clinoptilolite (strontium exchange rate 82.1%) as in Experimental Example 2, the difference in retention time between nitrogen and methane was evaluated. Table 1 shows the difference in retention time between nitrogen and methane at 25 ° C.

<Experimental Example 6: Example>
Using strontium exchanged clinoptilolite with a strontium exchange rate of 84.5%, the difference in retention time between nitrogen and methane was evaluated. Table 1 shows the difference in retention time between nitrogen and methane at 25 ° C.

<Experimental Example 7: Example>
Using strontium exchanged clinoptilolite with a strontium exchange rate of 38.4%, the difference in retention time between nitrogen and methane was evaluated. Table 1 shows the difference in retention time between nitrogen and methane at 25 ° C.

<Experimental Example 8: Comparative Example>
Using the same calcium exchange clinoptilolite (Ca exchange rate 68.8%) as in Experimental Example 1, the difference in retention time between nitrogen and methane was evaluated. Table 1 shows the difference in retention time between nitrogen and methane at 25 ° C.

<Experimental Example 9: Comparative Example>
Using calcium exchange clinoptilolite with a Ca exchange rate of 36.8%, the difference in retention time between nitrogen and methane was evaluated. Table 1 shows the difference in retention time between nitrogen and methane at 25 ° C.

<Experimental Example 10: Comparative Example>
Using calcium exchange clinoptilolite with a Ca exchange rate of 76.5%, the difference in retention time between nitrogen and methane was evaluated. Table 1 shows the difference in retention time between nitrogen and methane at 25 ° C.

  Table 1 and FIG. 5 summarize the results of Experimental Examples 3-10. As can be seen from Table 1, strontium-exchanged clinoptilolite has a greater difference in retention time than calcium-exchanged clinoptilolite, indicating that it has excellent adsorption separation characteristics. Furthermore, it can be seen that when the strontium exchange rate is 70% or more, the difference in retention time increases rapidly as the strontium exchange rate increases, and the separation performance of nitrogen and methane is improved.

Thus, it was found that the adsorption separation method can obtain a very high CH ₄ concentration and can be maintained for a long time. Therefore, based on this fact, it is possible to efficiently obtain a gas with a high CH ₄ concentration continuously by preparing two towers filled with this agent, that is, strontium exchanged ptyrolite, and alternately performing adsorption and regeneration. It becomes.

Under these conditions, two containers filled with an adsorbent were prepared, and gas was circulated alternately. A high-concentration CH ₄ gas was obtained by performing an operation for ensuring a cycle time of 1 to 2 minutes and a time for making the system uniform at the time of switching for 1 second.

<Experimental example 11: Example>
Using a strontium-exchanged clinoptilolite molded body (additional example) and a commercially available nitrogen adsorbent (additional comparative example), separation evaluation of “CH ₄ —N ₂ ” by the PSA method was performed in the same separation method as described above. . Experimental Example 11: Separation conditions in the examples are as follows.

<Experimental equipment, operation>
FIG. 6 is a diagram illustrating the experimental apparatus used in Experimental Example 11 and the operation thereof. As shown in FIG. 6, nitrogen separation adsorbent-filled containers AT1 and AT2 are arranged. The adsorbent filling containers AT1 and AT2 are filled with an adsorbent for nitrogen separation in the same manner as shown as the “adsorbent test sample” in FIG.

A conduit for supplying methane gas containing nitrogen (N ₂ ) as a mixed gas is connected to the mixed gas supply side to the nitrogen separation adsorbent filled containers AT1 and AT2. That is, a mixed gas conduit provided with a flow rate regulator (MFC) and an electromagnetic on-off valve SV11 is disposed on the test gas supply side to the nitrogen separation adsorbent-filled containers AT1 and AT2.

  In this experimental apparatus, the experiment can be advanced through steps 1 → procedure 2 → procedure 3 → procedure 4 by operating the electromagnetic on-off valves (= valves) SV1 to SV14.

<1. Step 1>
Procedure 1 is step 1, in which gas is separated in the adsorption tank 1 and the adsorption tank 2 is regenerated. At this time, among the solenoid valves SV1 to SV14, SV1, SV4, SV7, SV11, SV12, and SV14 are opened, and the other solenoid valves are closed. The vacuum pump PU is activated.

<2. Step 2>
Procedure 2 is the pressure equalization in step 2. At this time, among the solenoid valves SV1 to SV14, SV5, SV6, SV8, SV9, SV10, SV11, SV12, SV14 are opened, and the other solenoid valves are closed. The vacuum pump PU is activated.

<3. Step 3>
Procedure 3 is step 3, in which the adsorption tank 1 is regenerated and gas is separated in the adsorption tank 2. At this time, among the solenoid valves SV1 to SV14, SV2, SV3, SV8, SV11, SV12, and SV14 are opened, and the other solenoid valves are closed. The vacuum pump PU is activated.

<4. Step 4>
Procedure 4 is the pressure equalization in step 4. At this time, among the solenoid valves SV1 to SV14, SV5, SV6, SV8, SV9, SV10, SV11, SV12, SV14 are opened, and the other solenoid valves are closed. The vacuum pump PU is activated.

By using the experimental apparatus shown in FIG. 6, a commercially available nitrogen adsorbent: molecular sieve carbon is used as a comparative example, and a strontium-exchanged clinoptilolite shaped body adsorbent is used as an example. The separation evaluation of CH ₄ and N ₂ source gases was performed. A mixed gas having a CH ₄ concentration of 90 vol% and an N ₂ concentration of 10 vol% was used as the source gas. In FIG. 6, “Summary of test using source gas (incoming gas) with CH ₄ concentration of 90 vol% and N ₂ concentration of 10 vol%” is displayed at the bottom.

  The compact adsorbent used for the separation evaluation was prepared as follows. To 100 parts by weight of clinoptilolite powder, 20 parts by weight of clay, 5 parts by weight of molding aid CMC, and an appropriate amount of water are added to form a cylindrical shape with a diameter of 1.5 mm, dried at 100 ° C., 600 ° C. And strontium exchange to give a strontium exchange rate of 83% and dehydration at 500 ° C.

Table 2 shows the results obtained in this example and the comparative example. Here, the recovery rate of the product CH ₄ is as shown in the formula (1). That is, the recovery rate of the product CH ₄ is defined by the formula (1).

As shown in Table 2, for the product CH ₄ concentration, a very high value of 99.6 vol% was obtained according to the separating agent: strontium exchanged clinoptilolite molded product. On the other hand, 93.4 vol% was the maximum value for the product CH ₄ concentration obtained from a commercially available nitrogen adsorbent (molded article).
Under the condition where the product CH ₄ concentration is about 93 vol%, in the separating agent: strontium exchanged clinoptilolite molded product, the product CH ₄ recovery rate is significantly higher than that of the commercially available nitrogen adsorbent (molded product) and the gas is four times as much. The quantity was found to be manageable.

Further, as shown in Table 2, when the product gas amount is increased, the product CH ₄ concentration is decreased, but the recovery rate is increased. Since the CH ₄ concentration in the product and the recovery rate are in a trade-off relationship, gas concentration is performed under suitable conditions according to needs.

1-9 Raw material gas conduit 11 Adsorbent filling container V (1) -V (8) On-off valve

Claims (6)

Carbonization containing nitrogen and containing methane as a main component, characterized by using an adsorbent for nitrogen separation comprising strontium at an ion exchange site and comprising a synthetic clinoptilolite having a strontium exchange rate of 79.7 mol% or more Method for separating nitrogen from hydrogen gas.   The method for separating nitrogen from a hydrocarbon gas containing nitrogen and containing methane as a main component according to claim 1, wherein the nitrogen separating adsorbent comprising the synthetic clinoptilolite is a molded body. A method for separating nitrogen from hydrocarbon gas containing methane as a main component.   The hydrocarbon containing nitrogen and containing methane as a main component according to claim 1 or 2, wherein the hydrocarbon gas containing nitrogen and containing methane as a main component is at least one of methane, natural gas, city gas, and digestive gas. Method for separating nitrogen from gas. Carbonization containing nitrogen and containing methane as a main component, characterized by using an adsorbent for nitrogen separation comprising strontium at an ion exchange site and comprising a synthetic clinoptilolite having a strontium exchange rate of 79.7 mol% or more Nitrogen separator from hydrogen gas. The nitrogen separator for hydrocarbon gas containing nitrogen and containing methane as a main component according to claim 4 , wherein the nitrogen separating adsorbent comprising the synthetic clinoptilolite is a molded body. Nitrogen separator from hydrocarbon gas containing methane as the main component. The hydrocarbon containing nitrogen and containing methane as a main component according to claim 4 or 5 , wherein the hydrocarbon gas containing nitrogen and containing methane as a main component is at least one of methane, natural gas, city gas, or digestion gas. Nitrogen separator from gas.

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