JPH0519597B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention is directed to converting a low-calorie raw material gas consisting of a low-calorie component and/or a non-combustible component such as H ₂ , CO, CO ₂ , N ₂ and a hydrocarbon into the low-calorie component and/or Separate and remove non-combustible components,
The present invention relates to a method for obtaining a high-calorie product gas. Conventional Technology In order to obtain a high-calorie product gas from a low-calorie raw material gas consisting of low-calorie components and/or non-combustible components such as H ₂ , CO, CO ₂ , N ₂ and hydrocarbons, these gases are extracted from the raw material gas. It is necessary to efficiently separate and remove low-calorie components and/or non-combustible components. Conventionally, the following methods have been put into practical use as methods for removing these components from gases containing H ₂ , CO, CO ₂ or N ₂ . (i) Removal of H ₂ PSA method (pressure fluctuation adsorption separation method), membrane separation method, cryogenic separation method (ii) Removal of CO cryogenic separation method, copper ammonia method, COSORB method, CO methanation (iii) Removal of CO ₂ Hot alkali carbonate method, two-stage treatment method of hot alkali carbonate and monoethanolamine, PSA method (iv) Removal of N ₂ PSA method Cryogenic separation method Problems to be solved by the invention However, With the exception of the PSA method, the above-mentioned separation technologies for each gas alone generally require large equipment costs, as well as the thermal energy of electricity, steam, etc., and the combination of these technologies requires even more complicated equipment. Therefore, although it is suitable for processing a large volume of gas, it cannot be said to be advantageous for processing a medium or small volume of gas. It is also suitable for processing medium and small volumes of gas.
Regarding the PSA method, although it is possible to remove each gas individually, it is necessary to simultaneously remove these components from the raw material gas containing various low-calorie components and/or non-combustible components such as _{H 2} , CO, CO 2, and N ₂ . I can't find a way. In view of the above-mentioned situation, the present invention employs the PSA method to produce low-calorie raw material gas consisting of low-calorie components such as H ₂ , CO, CO ₂ , N ₂ and/or non-combustible components and hydrocarbons. The present invention was made in order to find an industrially advantageous method for obtaining a high-calorie product gas by separating and removing the low-calorie components and/or non-combustible components. Means for Solving the Problems The method for producing high calorie gas of the present invention includes H ₂ ,
A low-calorie raw material gas a consisting of low-calorie components and/or non-combustible components such as CO, CO ₂ , N ₂ and hydrocarbons is first passed through a pressure swing adsorption tower A filled with a clinoptilolite-based adsorbent. This intermediate product gas b is then introduced into a pressure swing adsorption tower B filled with a porous adsorbent having organic gas adsorption properties and subjected to a pressure swing operation to produce a high-calorie gas. Product gas c.
By discovering such a method, the above problems have been solved. In the method of the present invention, CO, CO ₂ and N ₂ components are first removed from the raw material gas in a pressure swing adsorption tower filled with a clinoptilolite adsorbent, that is, a clinoptilolite adsorbent packed tower A; Next, in a pressure swing adsorption tower filled with a porous adsorbent capable of adsorbing organic gases, that is, a porous adsorbent packed tower B, hydrocarbon components and H ₂ are separated. The raw material gas a that can be applied to the present invention includes H ₂ ,
A low-calorie raw material gas consisting of low-calorie components and/or non-combustible components such as CO, CO ₂ , N ₂ and hydrocarbons, such as coke oven gas generated from coke ovens, methanation reaction gas, etc. It will be done. However, the low calorie component and/or the non-combustible component may not include all of the components _H2 , CO, _CO2 , and _N2 . Note that the raw material gas a is
If it contains H ₂ O, it must be removed to below permissible limits. The presence of H ₂ O means that CO,
This is because it interferes with the adsorption of polar components such as CO ₂ . The clinoptilolite adsorbent in the clinoptilolite-based adsorbent packed column A is one made from naturally occurring clinoptilolite, that is, commercially available naturally occurring clinoptilolite as it is or ion-exchanged. Clinoptilolite is used after it has been subjected to chemical treatment and then crushed if necessary, or it is crushed and molded and sintered with the addition of an appropriate binder, or it is simply heat-treated from the above-mentioned clinoptilolite. A material made from clinoptilolite obtained by a method is also used. The porous adsorbent in the porous adsorbent packed tower B is preferably activated carbon, zeolite other than the above-mentioned clinoptilolite (for example, mordenite), or molecular sieving carbon. Other adsorbents can also be used as long as they are adsorbents. The adsorption operation in towers A and B can be performed at room temperature or under heating. More specifically, the method of the present invention is carried out by the following process operations. (1) Prior to introducing raw material gas a into clinoptilolite-based adsorbent packed column A, a step of pressurizing the same column A with intermediate product gas b derived from the same column A or raw material gas a itself, (2 ) CO, CO ₂ and N ₂ components contained in the raw material gas a are adsorbed by introducing the raw material gas a into the clinoptilolite-based adsorbent packed tower A, and an intermediate product gas from which these components are removed is produced. b
(3) A step of desorbing CO, CO ₂ and N ₂ components adsorbed in the clinoptilolite-based adsorbent-packed column A by depressurization operation and removing them as purge gas d, ( 4) Before introducing the intermediate product gas b derived from the clinoptilolite adsorbent packed tower A into the porous adsorbent packed tower B,
(5) Step of pressurizing the porous adsorbent-packed column B with the H2-rich gas e or intermediate product gas b itself derived from the H ₂ -rich gas e or intermediate product gas b derived from the clinoptilolite-based adsorbent packed column A; is introduced into the porous adsorbent packed tower B, thereby adsorbing the hydrocarbon components contained in the intermediate product gas b, and
( ₆ ) A step of desorbing the hydrocarbon components adsorbed in the porous adsorbent packed column B by depressurizing operation and recovering the product gas c. FIG. 1 is a flow sheet showing the flow of the above steps. Each of the above steps will be explained in detail below. Step 1 Step 1 consists of the step of pressurizing the column A with the intermediate product gas b derived from the column A, prior to introducing the raw material gas a into the column A packed with a clinoptilolite adsorbent. Note that, instead of or together with the intermediate product gas b, the raw material gas a itself may be used for pressurization. This pressure increase is necessary for the adsorption of CO, CO ₂ , N ₂ and the effective separation of these components from the hydrocarbon components. The pressure in this pressure increasing step 1 is 1 to 50Kg/cm ²
Although it can be selected from the range of 5 to 10 kg/cm 2 G, considering problems such as increase in energy cost for gas compression, it is preferable to set it to 5 to 10 kg/cm ² G. Step 2 In step 2, the raw material gas a is introduced into the clinoptilolite-based adsorbent packed column A.
Intermediate product gas b from which the CO, CO ₂ and N ₂ components contained in the gas are adsorbed and these components are removed.
The process consists of the step of deriving from the same tower A. This process is carried out in the following steps. The raw material gas a is introduced into the clinoptilolite-based adsorbent packed tower A whose pressure was increased in the previous step 1, and CO,
At the same time, CO ₂ and N ₂ components are adsorbed onto a clinoptilolite adsorbent, and hydrocarbon components are concentrated. Then, when the concentration of the hydrocarbon component with the highest boiling point in the intermediate product gas b derived from the column A reaches a concentration equal to or higher than that in the raw material gas a, the introduction of the raw material gas a is stopped. Note that a part of the intermediate product gas b from which CO, CO ₂ and N ₂ components have been removed and which has been extracted from the column A is used for pressurizing the column A in the above-mentioned step 1, and the rest is used for filling with the porous adsorbent described below. Introduced into tower B. Step 3 Step 3 consists of a step in which the CO, CO ₂ and N ₂ components adsorbed in the clinoptilolite-based adsorbent packed column A are desorbed by a reduced pressure operation and removed as purge gas d. That is, first, the pressure in column A is reduced from a predetermined pressure to atmospheric pressure, and then the pressure is further reduced to vacuum. Note that when the pressure is reduced to atmospheric pressure, a part of it may be recovered as intermediate product gas b, and the remainder may be removed as purge gas d. The degree of vacuum in this step 3 is appropriately set in the range of 0 to 760 torr to match the adsorption amount, desorption amount, or desorption rate of CO, CO ₂ , and N ₂ . Step 4 In step (4), before introducing the intermediate product gas b derived from the clinoptilolite-based adsorbent packed tower A into the porous adsorbent packed tower B, the intermediate product gas b derived from the porous adsorbent packed tower B is The process consists of pressurizing the porous adsorbent adsorption column B with _H2 -rich gas e. Note that, instead of or together with the H ₂ -rich gas e, the intermediate product gas b itself may be used for pressurization. This pressure increase is necessary for effective adsorption and concentration of hydrocarbon components onto the porous adsorbent. The pressure in this pressure increasing step 4 is 1 to 50Kg/cm ²
Although it can be selected from the range of 5 to 10 kg/cm 2 G, considering problems such as increase in energy cost for gas compression, it is preferable to set it to 5 to 10 kg/cm ² G. Step 5 In step 5, intermediate product gas b derived from clinoptilolite-based adsorbent packed column A is introduced into porous adsorbent packed column B.
In addition to adsorbing the hydrocarbon components contained in the
It consists of a step of deriving a gas e rich in H ₂ . This process is carried out in the following steps. When the intermediate product gas b derived from the clinoptilolite adsorbent packed tower A is introduced into the porous adsorbent packed tower B whose pressure has been increased in the previous step 4, and the hydrocarbon components are adsorbed by the porous adsorbent. At the same time, the _H2 component is concentrated. and the _H2 -rich gas e derived from column B.
The introduction of intermediate product gas b is stopped when, for example, CH ₄ is detected. Furthermore, the _H2 -rich gas e derived from tower B is
A part is used for pressurizing column B in the above-mentioned step 4,
Purge the remainder. Step 6 Step 6 consists of a step of desorbing the hydrocarbon components adsorbed in the porous adsorbent packed column B by a pressure reduction operation and recovering them as product gas c. That is, first, the pressure in column B is reduced from a predetermined pressure to atmospheric pressure, and then the pressure is further reduced to vacuum. Note that a part of the gas desorbed during depressurization may be purged as H ₂ -rich gas e, and the remainder may be recovered as product gas c. The degree of vacuum in step 6 is 0 to 760 torr.
It is set as appropriate from the range according to the amount of adsorption, amount of desorption, or rate of desorption of hydrocarbon components. As described above, the gas desorbed and recovered from tower B in step 6 by pressure reduction operation becomes product gas c, which is used as it is as a fuel or as an additive for producing alternative natural gas. Further, the CO, CO ₂ , and N ₂ concentrated gases desorbed from the tower A in step 3 by the pressure reduction operation become the purge gas d, which is used as a chemical raw material and the like. Similarly, in step 5, the
Gas e rich in H ₂ gas is used as a chemical raw material and the like. Effect In the present invention, CO, CO ₂ , N ₂ components and intermediate product gas b are separated from raw material gas a by pressure swing operation in clinoptilolite-based adsorbent packed tower A, and porous adsorbent packed tower B The hydrocarbon components and H ₂ are separated from the intermediate product gas b by the pressure swing operation in . EXAMPLES Next, the present invention will be explained in more detail with reference to Examples. Example 1 Example 1 shows the case where the first half of the process of the present invention was carried out, that is, the case where the PSA cycle was carried out in the clinoptilolite-based adsorbent packed column A. Raw material gas a having the composition shown in the raw material gas column of Table 1 was introduced into clinoptilolite-based adsorbent packed tower A filled with commercially available naturally produced clinoptilolite as an adsorbent, and the following operations were carried out. under conditions
The PSA cycle was repeated. Operating conditions Gas flow rate 800c.c./min Filling rate 240c.c. (21mmφ×690mmH) Pressure 7Kg/cm ² G Tower internal temperature Room temperature PSA cycle Pressure increase 60torr→7Kg/cm ² G (Intermediate product gas b Use) Adsorption 16 min Atmospheric pressure reduction 7Kg/cm ² G → 0Kg/cm ² G Vacuum pressure reduction 0Kg/cm ² G → 60torr Intermediate derived from clinoptilolite adsorbent packed column A during the second cycle implementation The composition of product gas b is shown in the intermediate product gas column of Table 1. Comparative Example 1 For comparison, the same raw material gas a as above was introduced into a column packed with a commercially available zeolite adsorbent MS-5A as an adsorbent, and the reaction was carried out under exactly the same conditions as in Example 1.
Table 1 also shows the results when the PSA cycle was repeated twice.

[Table] As can be seen from Table 1, in Example 1,
100% of CO ₂ and 50% of N ₂ were removed, resulting in an increase in the calorie content of intermediate product gas b. On the other hand, in Comparative Example 1 using MS-5A as the adsorbent,
CO ₂ is removed 100%, but N ₂ adsorption is poor, and CH ₄ , C ₂ H ₆ must be recovered as intermediate product gas b.
is quite adsorbed. As a result, the calorie of the intermediate product gas b is actually lower than the calorie of the raw material gas a. Example 2 Example 2 shows the case where the latter step of the method of the present invention was carried out, that is, the case where a PSA cycle was carried out in packed column B using activated carbon as a porous adsorbent. Commercially available activated carbon was used as the porous adsorbent, and a second
Intermediate product gas b having the composition shown in the intermediate product gas column of the table was introduced, and the PSA was
The cycle was repeated. Note that the total amount of gas desorbed during atmospheric pressure reduction and vacuum reduction was defined as product gas c. Operating conditions Gas flow rate 400c.c./min Filling rate 240c.c. (21mmφ×690mmH) Pressure 6Kg/ ^cm2G Tower internal temperature 30℃ PSA cycle Pressure increase 200torr→6Kg/ ^cm2G (rich in _H2 Adsorption 22min Purge 6Kg/cm ² G → 4Kg/cm ² G Atmospheric pressure reduction 4Kg/cm ² G → 0Kg/cm ² G Vacuum pressure reduction 0Kg/cm ² G → 200torr Porous at the 30th cycle The composition of the product gas c recovered from the adsorbent packed column B is shown in the product gas column of Table 2.

【table】

[Table] As you can see from Table 2, hydrocarbon gas accounts for 75%
Concentrated to 93%, gas calories are 8770kcal/
It has significantly improved from Nm ³ to 10490kcal/Nm ³ . Example 3 Example 3 shows the case where all steps of the method of the present invention were carried out. Raw material gas a having the composition shown in the raw material gas column of Table 3 was introduced into a clinoptilolite-based adsorbent packed column A filled with naturally occurring clinoptilolite as an adsorbent, and the following experiment was carried out. under conditions
While carrying out the PSA cycle, tower A is placed in porous adsorbent packed tower B packed with commercially available activated carbon as an adsorbent.
Intermediate product gas b derived from was introduced, and a PSA cycle was performed under the following operating conditions. Note that the total amount of gas desorbed from the porous adsorbent-packed tower B during atmospheric pressure and vacuum reduction was defined as product gas c. Operating conditions of tower A Gas flow rate 800c.c./min Filling amount 240c.c. (21mmφ×690mmH) Pressure 7Kg/cm ² G Tower internal temperature Room temperature (approximately 20℃) PSA cycle Pressure increase 60torr→7Kg/cm ² G (using intermediate product gas b) Adsorption 16 min Atmospheric pressure reduction 7 Kg/cm ² G → 0 Kg/cm ² G Vacuum pressure reduction 0 Kg/cm ² G → 60 torr Operating conditions of column B Gas flow rate 400 c.c./min Filling Amount 240c.c. (21mmφ×690mmH) Pressure 6Kg/cm ² G Tower temperature 30℃ PSA cycle Pressure increase 200torr→6Kg/cm ² G (Using _H2 -rich gas e) Adsorption 22min Purge 6Kg/cm ² G → 4Kg/cm ² G Atmospheric pressure reduction 4Kg/cm ² G → 0Kg/cm ² G Vacuum pressure reduction 0Kg/cm ² G → 200torr Derived from clinoptilolite adsorbent packed tower A during the 5th cycle implementation. Table 3 shows the composition of the intermediate product gas b and the composition of the product gas c recovered from the porous adsorbent packed column B at the fifth cycle implementation.

[Table] As can be seen from Table 3, 100% of CO ₂ and 80% of N ₂ were removed in product gas c compared to raw material gas a. In addition, the recovery rate of product gas c (recovery rate of hydrocarbon components) is 60℃, and the gas calorie is from 7610 to
It was significantly improved to 10320kcal/Nm ³ . Example 4 Example 4 shows the case where all steps of the method of the present invention were carried out. An experiment was conducted under the same operating conditions as in Example 3, except that commercially available molecular sieving carbon (MSC) was used as the porous adsorbent and this MSC was packed into the porous adsorbent packed column B. However, the adsorption time in column B (the gas e derived from column B is initially
The time during which CH ₄ was observed was 12 minutes. Intermediate product gas b derived from clinoptilolite-based adsorbent packed column A during the fifth cycle execution
Table 4 shows the composition of the product gas c recovered from the porous adsorbent-packed column B during the fifth cycle.

[Table] As can be seen from Table 4 and Example 3, column B
When filled with MSC, the adsorption time is shorter because the adsorption capacity is smaller than that of activated carbon, and the N ₂ removal rate and product gas recovery rate (hydrocarbon recovery rate) are slightly lower than activated carbon. Although it tends to be low, the gas calorie is 7610kcal/Nm ³
It can be seen that the method of the present invention is ^superior . Example 5 Example 5 shows the case where all steps of the method of the present invention were carried out. Commercially available molecular sieves as porous adsorbents
An experiment was conducted under the same operating conditions as in Example 3, except that MS-5A was used and the porous adsorbent-packed column B was filled with MS-5A. However, the adsorption time in column B (the time during which CH ₄ was first observed in gas e derived from column B) was 10 minutes. Composition of intermediate product gas b derived from clinoptilolite-based adsorbent packed column A during the fifth cycle execution, and product gas c recovered from porous adsorbent packed column B during the fifth cycle execution. The composition is shown in Table 5.

[Table] As can be seen from Table 5 and Examples 3 and 4,
When tower B was filled with MS-5A, activated carbon and
Compared to activated carbon and MSC, the adsorption time is shorter due to the smaller adsorption capacity, and the N ₂
Although the removal rate and recovery rate of product gas c (hydrocarbon recovery rate) tend to be slightly low, the gas calories range from 7610kcal/ ^Nm3 to 9710kcal/Nm3.
^m3 , which shows that the method of the present invention is superior. Effects of the Invention Since the present invention consists of the above-described process arrangement, each process operation can be performed smoothly and efficiently, and the target high-calorie product gas can be recovered with a high yield. Therefore, by carrying out the method of the present invention,
It has great industrial significance because high-calorie gas can be produced at low cost from hydrocarbon gases containing H ₂ , CO, CO ₂ , N ₂ , etc. through a process that is simpler than conventional methods. In addition, during the production of high-calorie product gases, CO, CO ₂ and N ₂ concentrated gases separated from clinoptilolite-based adsorbent-packed tower A and H ₂ derived from porous adsorbent-packed tower B are used. Any of the rich gases can be used as chemical raw materials, etc., so they are advantageous in this respect as well.

[Brief explanation of drawings]

FIG. 1 is a flow sheet showing the process flow of the present invention. 1, 2, 3, 4, 5, 6... Process, a... Raw material gas, b... Intermediate product gas, c... Product gas, d
...Purge gas, e... _H2 -rich gas.

Claims (1)

[Claims] 1. A low-calorie raw material gas a consisting of low-calorie components such as H ₂ , CO, CO ₂ , N ₂ and/or non-combustible components and hydrocarbons is first treated with a clinoptilolite-based adsorbent. The intermediate product gas b is passed through the pressure swing adsorption tower A filled with the gas, and then this intermediate product gas b is passed through the pressure swing adsorption tower B filled with a porous adsorbent having organic gas adsorption properties.
A method for producing a high-calorie gas, characterized in that a high-calorie product gas (c) is produced by introducing the gas into a gas and performing a pressure swing operation. 2. Claim 1, wherein the clinoptilolite adsorbent is made from naturally occurring clinoptilolite or from clinoptilolite obtained by a synthetic method. Manufacturing method described. 3. The manufacturing method according to claim 1, wherein the porous adsorbent having organic gas adsorption properties is activated carbon, zeolite other than clinoptilolite, or molecular sieving carbon. 4. A low-calorie raw material gas a consisting of low-calorie components such as H ₂ , CO, CO ₂ , N ₂ and/or non-combustible components and hydrocarbons is first subjected to pressure swing adsorption filled with a clinoptilolite adsorbent. By passing through column A, intermediate product gas b is obtained, and then this intermediate product gas b is introduced into pressure swing adsorption column B filled with a porous adsorbent having organic gas adsorption properties to perform a pressure swing operation. (1) Before introducing the raw material gas a into the clinoptilolite-based adsorbent-packed column A, intermediate product gas b derived from the column A or the raw material gas a itself is prepared. (2) Introducing the raw material gas a into the clinoptilolite-based adsorbent packed tower A to adsorb CO, CO ₂ and N ₂ components contained in the raw material gas a. , intermediate product gas b from which these components have been removed
(3) A step of desorbing CO, CO ₂ and N ₂ components adsorbed in the clinoptilolite-based adsorbent-packed column A by depressurization operation and removing them as purge gas d, ( 4) Before introducing the intermediate product gas b derived from the clinoptilolite adsorbent packed tower A into the porous adsorbent packed tower B,
(5) Step of pressurizing the porous adsorbent-packed column B with the H2-rich gas e or intermediate product gas b itself derived from the H ₂ -rich gas e or intermediate product gas b derived from the clinoptilolite-based adsorbent packed column A; is introduced into the porous adsorbent packed tower B, thereby adsorbing the hydrocarbon components contained in the intermediate product gas b, and
( ₆ ) a step of desorbing the hydrocarbon components adsorbed in the porous adsorbent packed column B by decompression operation and recovering it as a product gas c. Claim 1:
Manufacturing method described in section.