JP2000104080A - Production of high-calorie gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a high-calorie gas at a low cost by subjecting a pretreated coal gas to CO modification and then to membrane separation and collecting the nonpermeation-side gas. SOLUTION: Coal gas is fed to a reactor filled with an Ni-Mo catalyst or the like and is subjected to deoxygenation, deolefinization, and desulfurization at an inlet temp. of 200-350 deg.C and an outlet temp. of 350-430 deg.C. The pretreated coal gas is fed to a CO modification reactor filled with a Fe-Cr catalyst or the like; then CO gas in the coal gas is converted with steam at an inlet temp. of 200-330 deg.C into hydrogen gas and carbon dioxide gas; and thus treated coal gas is fed to a membrane separator to cause carbon dixode to permeate and be separated, giving a high-calorie gas contg. methane. The high-calorie gas is fed to a methanization reactor filled with a platinum-group metal catalyst and is methanized in the presence of steam at an inlet temp. of 230-350 deg.C and an outlet temp. of 300-550 deg.C to give a high-calorie gas having a calorific value of 7,000-8,600 kcal/Nm3, to which LPG is added with a carburettor to give a gas having a calorific value of 11,000 kcal/Nm3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a coal gas (hereinafter referred to as C)
Also called OG. The present invention relates to a method for producing a high calorie gas or a so-called alternative natural gas (hereinafter, also referred to as SNG) using) as a raw material, and a production apparatus used for the method.

[0002]

2. Description of the Related Art In recent years, the ratio of liquefied natural gas (hereinafter, also referred to as LNG) in city gas feedstock has been rapidly increasing, and so-called natural gas conversion tends to be further promoted in the future. By the way, LNG requires large-scale equipment operated under certain suitable conditions for its transportation, storage, vaporization, etc., so that it may not always be able to properly respond to demand fluctuations caused by seasons, business fluctuations, etc. is there. Furthermore, LN
It is believed that excessive dependence on G may cause some problems in terms of stable supply of raw materials. Therefore, by absorbing demand fluctuations and diversifying the raw materials, LNG should be used to maximize the merits of natural gas that uses LNG as its main raw material.
Development of a new method for producing SNG that does not depend on NG has been eagerly desired.

As a method of producing a high calorie gas from COG, for example, first, COG is passed through an absorbent such as a molecular sieve under pressure, and a high molecular hydrocarbon gas adsorbed by the absorbent and a low molecular weight gas not adsorbed are absorbed. And then desorbing the hydrocarbon gas from the adsorbent under reduced pressure to obtain a high calorie gas.
In this case, if a plurality of adsorption devices are provided, it is possible to continuously obtain high-calorie gas by alternately performing adsorption and desorption. However, in this method, since the function of the adsorbent is easily hindered by impurities in the COG, it is necessary to remove tar, benzol, naphthalene, and the like to substantially the entire amount, which requires a large-scale facility. Become.

[0004] Furthermore, it is conceivable to convert COG into a high calorie gas by so-called methanation. However, in this method, since the hydrogen in COG is excessive with respect to carbon, the calorific value of the produced gas is smaller than a desired value. Has the disadvantage of staying much lower.

As a method for solving such a problem, there is a method described in Japanese Patent Publication No. 60-8273. In this method, a coal gas to which naphtha and / or LPG as a carbon source is added is used as a raw material, which is subjected to ordinary pretreatment such as deoxygenation and desulfurization. This is a method of performing methanation treatment in the presence of an SNG, which is a method for producing SNG that solves the above-mentioned difficulties and has various advantages. Specifically, COG obtained by adding 0.01 to 0.1 mol of naphtha and / or LPG as a carbon source to 1 mol of coal gas is subjected to pretreatment such as deoxidation and desulfurization, and then the inlet temperature is set to 250 to 300 ° C, outlet temperature 300-550 ° C
High calorie derived from coal gas by methanation in the presence of a gasifying agent in the amount of S / C = 0.5-1.0 and steam as a cooling agent It is a method for producing gas.

However, this method requires the use of an expensive carbon source (LPG, naphtha, etc.) as an auxiliary material, and has the disadvantage of increasing the production cost for obtaining a high calorie gas. Further, it has been pointed out that there is a need to stably produce SNG even under circumstances where it is difficult to secure LPG raw materials by eliminating the need to use LPG as a carbon source.

[0007]

SUMMARY OF THE INVENTION The main object of the present invention is to:
An object of the present invention is to provide a method for producing high-calorie gas or alternative natural gas (also referred to as SNG) at low cost using only COG as a raw material without using an expensive carbon source, and a production apparatus that can be used for the method. . Another object of the present invention is to eliminate the need for LPG as a carbon source, so that even if it is difficult to secure LPG raw materials, SNG can be used.
It is an object of the present invention to provide a method capable of stably producing lipstick and a production apparatus which can be used for the method.

[0008]

Means for Achieving the Object The present inventor has conducted intensive studies to solve the above-mentioned problems, and as a result, using coal gas which has been subjected to pretreatment such as deoxygenation and desulfurization as a raw material, It has been found that the above object can be achieved by producing high-calorie gas by a method of membrane separation after CO conversion or a method of membrane separation after methanation reaction.

That is, the present invention provides the following high calorie gas production method and high calorie gas production apparatus.

[0010] 1. A method for producing a high-calorie gas, comprising subjecting a pretreated coal gas to CO conversion, and then performing membrane separation to collect a non-permeate-side gas.

2. A method for producing a high-calorie gas, characterized by further subjecting the non-permeate-side gas collected by the method of the above item 1 to a methanation reaction.

3. A method for producing a high calorie gas, comprising subjecting a pretreated coal gas to a methanation reaction, and then performing membrane separation to collect a non-permeate-side gas.

4. Item 4. A method for producing an alternative natural gas, comprising heating a high calorie gas by LPG after obtaining a high calorie gas by any one of the above items 1 to 3.

5. The method for producing an alternative natural gas according to the above item 4, wherein the heat is increased by LPG so as to satisfy the 13A standard.

6. 6. The method for producing an alternative natural gas according to the above item 4 or 5, wherein the heat is increased by LPG so as to satisfy the 13A standard of a calorific value of 11000 Kcal / Nm ³ .

[7] An apparatus for producing high-calorie gas, including a pretreatment reactor, a CO shift converter, and a membrane separation device, used for producing high-calorie gas by the method of the above item 1.

8. Item 3. An apparatus for producing high-calorie gas, comprising a pretreatment reactor, a CO shift converter, a membrane separation device, and a methanation reactor, which is used for producing high-calorie gas by the method of the above item 2.

9. Item 3. An apparatus for producing a high-calorie gas, comprising a pretreatment reactor, a methanation reactor, and a membrane separation apparatus, used for producing a high-calorie gas by the method of the above item 3.

[0019]

DETAILED DESCRIPTION OF THE INVENTION In the method of the present invention, coal gas (COG) is used as a raw material. According to the method of the present invention, LP
Since only COG is used as a raw material without using an expensive carbon source such as G or naphtha as an auxiliary raw material, high calorie gas and alternative natural gas (SNG) can be produced at low cost.

The COG used in the method of the present invention is subjected to the following treatments after the pretreatment. As the pretreatment, treatments such as deoxygenation, olefin removal, and desulfurization may be performed in a conventional manner.

For example, the pretreatment can be performed using a Ni-Mo-based, Co-Mo-based, or other catalyst that is a catalyst for a deoxygenation reaction that also functions as a desulfurization catalyst. When these catalysts are used, COG is deoxygenated and deorganized sulfur is hydrogenated by hydrogenation of the raw COG. These deoxygenation, deolefin, desulfurization and other treatments
It can be carried out according to a conventional method.
About 0 to 350 ° C., pressure in the reactor 5 to 50 kg / cm ²
The treatment may be performed under the conditions of about G and the reactor outlet temperature of about 350 to 430 ° C. In addition, for example, COG is sent to an adsorption desulfurizer, and ordinary adsorption desulfurization with ZnO is performed.

In this way, the pretreated COG
It is preferable that the oxygen content and the olefin content are substantially zero, and the total sulfur concentration is 1 ppm or less. Since all of the above desulfurization reactions are exothermic, C
Heat is recovered from the OG by a waste heat boiler or the like.

The COG to be supplied to the pretreatment step has previously been subjected to a conventional method to remove pitch, ammonia, cyan, naphthalene, benzol and the like.

According to the present invention, using COG subjected to pretreatment such as deoxygenation and desulfurization as described above, (1) C
After passing through the O shift process and the membrane separation process, if necessary, a method of obtaining a high calorie gas through the methanation process (first method), (2) obtaining a high calorie gas through the methanation process and the membrane separation process A high calorie gas can be produced by two types of methods (second method).

It is needless to say that the high-calorie gas obtained by these methods can be used as it is, but is then sent to an LPG heat-up device, where LPG is added to increase the temperature to obtain alternative natural gas. Can also.

Hereinafter, the above two methods will be described in detail.

(1) First method: The first method will be described with reference to the flowchart shown in FIG.

The OCG pretreated in the pretreatment reactor (1) is fed to a CO converter (2) and subjected to a CO conversion treatment. As the CO conversion process, in the presence of an iron-chromium-based catalyst, a copper-zinc-based catalyst, or the like, a process of converting carbon monoxide gas contained in COG into hydrogen gas and carbon dioxide gas by adding steam may be performed. . The operating condition of the CO converter (2) may be set to an inlet temperature of about 200 ° C. to 330 ° C.

After that, the COG subjected to the CO conversion treatment
Is sent to the membrane separation device (3). Membrane separation device (3)
A known separation apparatus that transmits carbon dioxide and does not transmit methane and has high decarbonation efficiency may be used. By performing membrane separation using such a membrane separation apparatus, a carbon dioxide-rich off-gas is obtained on the permeate side, and a high calorie gas is obtained on the non-permeate side.

Further, the high calorie gas obtained in the membrane separation step further reduces the CO concentration,
In order to make the concentration less than 0.1% by volume, it may be supplied to a methanation reactor (not shown) and subjected to a methanation treatment. Methanation treatment is performed using a platinum group metal catalyst, Ni
The amount of water vapor in which S / C (the number of oxygen atoms in water vapor per carbon molecule in hydrocarbon) is about 0.0 to 1.0 in the presence of a system catalyst, a noble metal catalyst, etc. Perform in the added situation. The temperature at the inlet of the reactor in the methanation step is about 230 to 350 ° C., and the pressure inside the reactor is 5 to 10 k.
g / cm ² G, reactor outlet temperature is 300-550 ° C
It is preferable to set the degree. Although the product gas after the methanation reaction varies depending on the methanation reaction conditions, the initial calorific value of COG is 4800 to 5400 Kcal / Nm ³ , whereas the calorific value of about 7000 to 8600 Kcal / Nm ³ is high. It becomes calorie gas.

Needless to say, the obtained high-calorie gas can be used as it is, but the heat is increased by adding LPG in the intensifier (4), and SNG (also referred to as product gas. Usually, the calorific value is 11,000 Kcal / Nm ^3). Of 13
A standard SNG. ).

(2) Second method: The second method will be described with reference to the flowchart shown in FIG.

The pretreated COG in the pretreatment reactor (1) is fed to the methanation reactor (5), where the COG is subjected to methanation. The methanation treatment uses a Ni-based catalyst,
In the presence of a noble metal catalyst or the like, S / C (the number of oxygen atoms in water vapor per carbon molecule in hydrocarbon) is 0.5 to
This can be performed in a situation where about 1.0 amount of water vapor is added to COG. The temperature at the inlet of the reactor in the methanation step is about 250 to 350 ° C., and the pressure in the reactor is 5 to 10
kg / cm ² G, reactor outlet temperature is 230-550
It is preferable that the temperature be about ° C. Although the product gas after the methanation reaction varies depending on the methanation reaction conditions, the initial calorific value of COG is 4800 to 5400 Kcal / Nm ³ , but the calorific value of about 6800 to 8600 Kcal / Nm ³ is high. It becomes calorie gas.

It goes without saying that this product gas can be used as it is, but it is further fed to the membrane separation device (3) to be separated into off-gas and high-calorie gas. As the membrane separation device (3), a separation device that transmits carbon dioxide and does not transmit methane and has high decarbonation efficiency is used. By performing membrane separation using such a membrane separation apparatus, off-gas is obtained on the permeate side, and high calorie gas is obtained on the non-permeate side.

The high calorie gas obtained in this way is
Needless to say, it can be used as it is, but in the intensifier (4), the temperature is increased by adding LPG, and SNG (also referred to as product gas. Usually, the calorific value is 11,000 Kcal /
It is a SNG of Nm ³ of 13A standard. ).

[0036]

According to the present invention, the following remarkable effects are exerted.

(1) Without using an expensive carbon source,
High calorie gas or alternative natural gas (also called SNG) can be produced at low cost using only COG as a raw material.

(2) The off-gas on the permeate side of the membrane separation apparatus is effectively used as fuel gas for the plant of the present invention (in some cases, a combustion aid is used) or as fuel gas for other sections of the manufacturing plant. The thermal efficiency of the SNG manufacturing plant can be improved.

(3) In addition to the effects described above, the method of the present invention is extremely useful in expanding the use of COG whose use is relatively reduced with the introduction of LPG. In other words, COG, which is generated in large quantities as a by-product during the production of coke having various uses, had a problem of a decrease in demand for it. According to the present invention, this problem is caused by the conversion of COG to SNG. Completely resolved.

(4) By eliminating the need for LPG as a carbon source, even in situations where it is difficult to secure LPG raw materials,
NG can be manufactured stably.

[0041]

The present invention will be described in more detail with reference to the following examples.

Example 1 A COG raw material having the composition shown in Table 1 below was fed to a pretreatment reactor for deoxygenation, deolefinization, desulfurization, etc. filled with a Ni-Mo type and zinc oxide type catalyst. Inlet temperature 26
The pretreatment was performed under the conditions of 0 ° C., a pressure inside the reactor of 8 kg / cm ² G, and a temperature at the outlet of the reactor of 400 ° C. Thus, the oxygen content and the olefin content in the COG were substantially zero, and the total sulfur content was 1 ppm or less.

Next, the pretreated COG was fed to a CO converter filled with a copper-zinc catalyst. The CO shift process is performed according to a conventional method, and the inlet temperature of the CO shift is about 21
0 ° C, outlet temperature about 260 ° C, reactor pressure about 7kg
/ Cm ² G.

The gas obtained by the CO conversion is further fed to a membrane separation device, and the pressure on the permeate side is 6.5 kg / cm.
² G, subjected to membrane separation under a pressure 0.0 kg / cm ² G on the permeate side, resulting methane-rich high-calorie gas to the non-permeate side, to obtain a hydrogen-rich off-gas to the permeate side.

The high calorie gas obtained by the above method can be used as it is, but by increasing the heat with LPG, 13A having a calorific value of 11,000 Kcal / Nm ³ is obtained.
Standard SNG could be manufactured.

Table 2 below shows the flow rates of the source gas and the off-gas when the product gas is 100 Nm ³ / hour.

The composition and calorific value of the thus obtained product gas (13A standard SNG with a calorific value of 11,000 Kcal / Nm ³ ) are as shown in Table 3 below.

Example 2 A COG raw material having the composition shown in Table 1 below was fed to a pretreatment reactor for deoxygenation, deolefinization, desulfurization, etc. filled with a Ni-Mo type and zinc oxide type catalyst, and the reactor inlet Temperature 26
The pretreatment was performed under the conditions of 0 ° C., a pressure inside the reactor of 8 kg / cm ² G, and a temperature at the outlet of the reactor of 400 ° C. Thus, the oxygen content and the olefin content in the COG were substantially zero, and the total sulfur content was 1 ppm or less.

Next, the pretreated COG is supplied to a methanation reactor filled with a platinum group catalyst, and S / C = 0.
The methanation reaction was carried out in the presence of water vapor of 5. The inlet temperature of the methanation reactor is about 300 ° C and the outlet temperature is about 2
At 50 ° C., the pressure in the reactor was about 7.5 kg / cm ² G.

The high-calorie gas obtained by the methanation reaction is further fed to a membrane separation device, where the pressure on the permeate side is 7 kg.
/ Cm ² G and a pressure of 0 Kg / cm ² G on the permeation side, membrane separation was performed, a high calorie gas was obtained on the non-permeation side, and an off-gas was obtained on the permeation side.

Further, the heat of the high calorie gas is increased by LPG so that the calorific value of 11,000 Kcal / Nm ³
A standard SNG could be manufactured.

Table 2 below shows the flow rates of the source gas and the off-gas when the product gas is 100 Nm ³ / hour.

The composition and calorific value of the thus obtained product gas (13A standard SNG having a calorific value of 11,000 Kcal / Nm ³ ) are as shown in Table 3 below.

Comparative Example 1 A COG raw material having the composition shown in Table 1 below and LPG as an auxiliary raw material (carbon source) were mixed, and the mixed gas was deoxygenated and deolefinized with a Ni-Mo type and zinc oxide type catalyst. It is fed to the pretreatment reactor for desulfurization etc., and the reactor inlet temperature is 300
C., the reactor pressure was 7.5 kg / cm ² G, and the reactor outlet temperature was 250 ° C. Thus, the oxygen content and the olefin content in the COG were substantially zero, and the total sulfur content was 1 ppm or less.

Next, the pretreated mixed gas is supplied to a methanation reactor filled with a noble metal catalyst, and the S / C
The methanation reaction was carried out in the presence of water vapor at which = 0.8. The inlet temperature of the methanation reactor is about 300 ° C., the outlet temperature is about 250 ° C., and the pressure inside the reactor is about 7.5 kg / cm ² G
Met.

Then, by heating the high calorie gas obtained in the methanation reaction step with LPG, SNG having a calorific value of 11,000 Kcal / Nm ³ and 13A standard could be produced.

Table 2 below shows the flow rates of the raw material gas and auxiliary raw material gas when the product gas is 100 Nm ³ / hour.

The composition and calorific value of the thus obtained product gas (13 A standard SNG with a calorific value of 11,000 Kcal / Nm ³ ) are as shown in Table 3 below.

[0059]

[Table 1]

[0060]

[Table 2]

[0061]

[Table 3]

As is evident from the above results, according to the method of the present invention, only COG is used as a raw material, and the calorific value is 1
It was possible to manufacture 13K SNG of 1000 Kcal / Nm ³ .

[Brief description of the drawings]

FIG. 1 is a flowchart showing a manufacturing process of SNG according to a first method of the present invention.

FIG. 2 is a flowchart showing a process of manufacturing SNG according to the second method of the present invention.

FIG. 3 is a flowchart showing a conventional SNG manufacturing process.

[Explanation of symbols]

 Reference Signs List 1 Pretreatment reactor 2 CO converter 3 Membrane separation device 4 Heater 5 Methanation reactor

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tominori Sato 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka Inside Osaka Gas Co., Ltd. (72) Shinichi Nagase 4-chome, Hirano-cho, Chuo-ku, Osaka-shi, Osaka No. 1-2 F-term in Osaka Gas Co., Ltd. (reference) 4H060 AA01 AA02 BB02 BB12 BB13 BB32 BB34 CC18 DD02 DD04 GG08

Claims (9)

[Claims] 1. A method for producing a high-calorie gas, comprising subjecting a pretreated coal gas to CO conversion and then performing membrane separation to collect a non-permeate gas. 2. A method for producing a high-calorie gas, comprising subjecting the non-permeate gas collected by the method of claim 1 to a methanation reaction. 3. A method for producing a high calorie gas, comprising: subjecting a pretreated coal gas to a methanation reaction, and then performing membrane separation to collect a non-permeate gas. 4. A method for producing an alternative natural gas, characterized in that after obtaining a high calorie gas by the method according to any one of claims 1 to 3, the heat is increased by LPG. 5. The method according to claim 4, wherein the heat is increased by LPG so as to satisfy the 13A standard. 6. The calorific value of 11,000 Kcal / Nm ³ of 13.
The method for producing an alternative natural gas according to claim 4 or 5, wherein the heat is increased by LPG so as to satisfy the A standard. 7. A high calorie gas production apparatus used for producing a high calorie gas by the method of claim 1, comprising a pretreatment reactor, a CO shift converter, and a membrane separation device. 8. A high calorie gas production apparatus used for producing a high calorie gas by the method of claim 2, comprising a pretreatment reactor, a CO shift converter, a membrane separation device, and a methanation reactor. 9. A high calorie gas production apparatus used for producing a high calorie gas by the method of claim 3, which comprises a pretreatment reactor, a methanation reactor, and a membrane separation device.