JP2008162822A - Coal-seam gas reforming system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To propose a coal-seam gas reforming system by which efficient conversion of coal-seam gas to fuel such as hydrogen is achieved in a cost-wise excellent way, and which can provide hydrogen for coal liquefaction on site and can also contribute to promotion of coal liquefaction. <P>SOLUTION: This reforming system is equipped with a reforming reactor 2 for supplied coal-seam gas 1. The coal-seam gas 1 comprises wet gas accompanied with moisture, is based on methane and slightly contains ethane and propane. In the reforming reactor 2, the coal-seam gas 1 is reacted with steam in the presence of a catalyst 7 under heating at a high temperature to perform steam reforming, and the formed reformed gas 8 is composed mainly of hydrogen, carbon monoxide and carbon dioxide. The hydrogen obtained as the reformed gas 8 is used as various fuel and energy sources and is also used, e.g., in coal liquefaction to obtain low molecular liquid hydrocarbon from coal of a high molecular structure. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a coal bed gas reforming system. That is, the present invention relates to a reforming system that reforms coal bed gas into hydrogen or the like.

《Technical background》
Coal bed gas is a combustible gas mainly composed of methane, and is contained in the coal bed of coal.
That is, coal is a product obtained by a chemical regeneration reaction between buried and deposited plants, and coal bed gas is gas separated in such a coalification reaction process. In view of the combustibility, the coal bed gas is extracted from the coal bed and guided to the ground to ensure the safety of the coal mining operation.

<Conventional technology>
As described above, the coal seam gas derived from the coal seam has been conventionally released into the atmosphere as it is or used as fuel as it is.
First, the conventional example of releasing coal seam gas as it is to the atmosphere is the easiest and has been mainstream in the past, but recently it is in a situation of tightening regulations as a cause of global warming. That is, methane, which is the main component of the coal seam gas, is said to have a greenhouse effect 21 times that of carbon dioxide, which has been regarded as a problem.
On the other hand, the conventional example in which the coal bed gas, that is, methane, is directly used as a fuel or the like has been put into practical use without such an adverse effect. For example, as a fuel for household gas, boiler, gas turbine, gas engine, etc. It is also used for the production of carbon black and methanol.

By the way, the following subject was pointed out about such a prior art example.
<< About the first problem >>
First, the coal bed gas is a wet gas accompanied by moisture, and drainage work is required. That is, due to free water in the coalification reaction process, injection water in the coal mining process, etc., the coal seam gas is composed of a wet gas accompanied by a large amount of moisture. It required processes and equipment such as draining and methane concentration.
Furthermore, for this type of conventional example, there has been a demand for more efficient use of coal bed gas and more efficient fuel conversion.

<About the second issue>
Secondly, coal liquefaction utilization is one theme for coal, and liquefied coal is attracting attention as a fuel that generates a large amount of heat and is easy to handle. That is, the practical application of coal liquefaction is progressing, in which high-molecular coal is converted into liquefied hydrocarbons with low molecular weight by hydrogenation.
In this type of conventional example, hydrogen generated and prepared separately is transported to a coal liquefaction site (factory) by a cylinder or the like, and the coal liquefaction operation is carried out. There was a strong demand for it to be extremely efficient if it could generate and supply hydrogen directly near a coal liquefaction factory, which is often located in the coal mine area.

<< About the present invention >>
The coal bed gas reforming system of the present invention has been made to solve the above-described problems of the conventional examples in view of such a situation.
The present invention firstly proposes a coal bed gas reforming system that realizes efficient coal bed gas fuelization while being excellent in cost, and secondly, can contribute to the promotion of coal liquefaction. With the goal.

<About Claim>
The technical means of the present invention for solving such a problem is as follows. First, claim 1 is as follows. The coal bed gas reforming system according to claim 1 includes a coal bed gas supply means and a reforming reactor for reforming the supplied coal bed gas. The coal bed gas is composed of a wet gas accompanied by moisture, and the reforming is performed under high temperature heating under a catalyst.
Claim 2 is as follows. The reforming system for coal seam gas according to claim 2 is the reforming system according to claim 1, wherein the coal seam gas is mainly composed of methane, and the reforming by the reforming reactor is modified by reacting the coal seam gas with water vapor. The reformed gas is characterized by being mainly composed of hydrogen and carbon monoxide or carbon dioxide.

Claim 3 is as follows. The reforming system for coal bed gas according to claim 3 is characterized in that, in claim 2, when the steam reforming is performed in the reforming reactor, the amount of water actually required is 1.4 times or more the weight of methane to 3.0. The supply heat quantity actually required is 165.1 kJ or more and 206.2 kJ or less per mole of the methane.
Claim 4 is as follows. The coal bed gas reforming system according to claim 4 is the reforming system according to claim 2, wherein hydrogen of the reformed gas generated in the reforming reactor is used for coal liquefaction, and the coal having a polymer structure is reduced. It is used to form a liquefied hydrocarbon that has been molecularized.
Claim 5 is as follows. The coal bed gas reforming system according to claim 5 is the coal bed gas reforming system according to claim 2, wherein the coal bed gas contains methane as a main component and also contains a small amount of ethane and propane. And steam reforming to the reformed gas mainly composed of carbon monoxide and carbon dioxide.

<About the action>
Since the present invention comprises such means, the following is achieved.
(1) The coal seam gas derived from the coal seam is supplied to the reforming reactor via the supply means.
(2) Coal bed gas consists of wet gas accompanied by moisture, is mainly composed of methane, and also contains a small amount of ethane and a small amount of propane. The reforming reactor is maintained at 650 ° C. or higher, for example, about 800 ° C.
(3) Therefore, the coal bed gas is reformed in the reforming reactor by reacting with water vapor based on the action of heat and the action of the catalyst filled inside.
(4) That is, methane, which is the main component of the coal bed gas, reacts with water vapor to be steam reformed to a reformed gas such as hydrogen, carbon monoxide, carbon dioxide. The same applies to ethane and propane.
(5) Reformed gas such as reformed and generated hydrogen is widely used for fuel and other applications.
(6) For example, hydrogen is used for coal liquefaction, and is used to make coal having a high molecular structure into a low molecular weight liquid fuel.
(7) Now, the coal bed gas reforming system of the present invention exhibits the following first and second effects.

<< First effect >>
First, efficient fuel conversion of coal seam gas is realized with excellent cost. That is, in the coal seam gas reforming system of the present invention, steam reforming of methane or the like of the coal seam gas can be performed using the accompanying moisture, and the reformed gas such as hydrogen produced can be provided as fuel or the like. It is. In particular, hydrogen is extremely excellent as a wide variety of fuels and energy sources as is well known.
Therefore, compared to the above-described conventional example, that is, the conventional example in which methane of the coal seam gas is directly used as fuel or the like, more efficient fuel conversion and energy efficient use are realized.
Furthermore, the configuration of the reforming reactor and the like is simple and easy, and the associated water is actively utilized, and the equipment cost and running cost are excellent. Further, compared to the above-described conventional example, the process and equipment for draining and concentrating can be greatly reduced and eliminated.

<< Second effect >>
Second, it can contribute to the promotion of coal liquefaction. That is, in the coal bed gas reforming system of the present invention, the coal bed gas is steam reformed into hydrogen or the like, and thus the obtained hydrogen can be used immediately for liquefaction of coal.
As is well known, liquefied coal obtained by hydrocracking coal is attracting attention as a liquid fuel that generates a large amount of heat and is easy to handle. However, the hydrogen required for coal liquefaction is collected at the coal liquefaction site (factory). Direct supply is also possible.
Unlike the above-described conventional example, hydrogen produced and prepared separately is not transported to the coal liquefaction site (factory) by a cylinder or the like. Necessary hydrogen can be supplied immediately, and coal liquefaction is greatly improved and promoted. In other words, the coal liquefaction site (factory) is often located in the coal mine area, but it is very efficient if coal bed gas and hydrogen generated in the same area can be used.
As described above, the effects exerted by the present invention are remarkably large, such as all the problems existing in this type of conventional example are solved.

《About drawing》
Hereinafter, the coal bed gas reforming system of the present invention will be described in detail based on the best mode for carrying out the invention shown in the drawings.
FIG. 1 is a configuration flowchart for explaining the best mode for carrying out the present invention.

<About coal seam gas 1>
The present invention relates to a reforming system for coal seam gas 1. First, the coal bed gas 1 will be described.
Coal is an oxygen-containing hydrocarbon compound that is a product of chemical regeneration reaction of plant organic matter made from buried and deposited plants. Coal bed gas 1 is gas separated in the process (coal bed production process) according to the degree of such a coalification reaction. Therefore, the coal seam gas 1 is composed of a combustible gas mainly composed of methane, and is contained in the coal seam. For example, it is said that about 30 m ^{3 is} contained per 1 ton of coal, and in some cases, 60 m ³ or more may spring out.
And in view of its flammability, the coal seam gas 1 needs to be extracted in advance to ensure the safety of coal mining operations, that is, to prevent gas explosion accidents and gas outburst accidents, and is sucked with a blower or the like before or during coal mining Then, it is guided to the ground via pipes and the like arranged along the tunnel.

The coal bed gas 1 thus induced is composed of a wet gas accompanied by a large amount of water such as water vapor, water droplets, water and the like. That is, the coal seam gas 1 is accompanied by a large amount of saturated water due to the penetration of fossil water released in the coalification reaction process (coal seam formation process), injection water in the coal mining boring process, and underground water such as rainwater and groundwater. Made of wet gas.
The components of the induced coal bed gas 1 as a dry gas (excluding moisture H ₂ O) are as follows. That is, the coal bed gas 1 is mainly composed of methane CH ₄ (for example, about 95%), further contains a small amount of ethane C ₂ H ₆ (for example, about 2%), and contains a small amount of propane C ₃ H _8. (For example, about 0.5%). The oxygen _{O 2,} nitrogen _{N 2,} also carbon dioxide CO _2, etc., are contained.
The coal bed gas 1 is like this.

<Reforming reactor 2 etc.>
Next, the reforming reactor 2 and the like will be described. The reforming system for the coal bed gas 1 includes a supply means 3 for the coal bed gas 1 and a reforming reactor 2 for reforming the supplied coal bed gas 1.
As described above, the supply means 3 includes a tank 4 that temporarily guides the coal bed gas 1 made of a wet gas accompanied with moisture while being guided to the ground. Then, the coal bed gas 1 accompanied by moisture is supplied from the tank 4 to the reforming reactor 2 via the pipe line 5.
The reforming reactor 2 is supplied with the coal bed gas 1 accompanied by moisture from the tank 4 of the supply means 3, is introduced with a heat quantity H from the heat source 6, and has a large number of heat passage paths disposed therein. The inside is heated at a high temperature of 650 ° C. or higher, for example, about 800 ° C.

Therefore, in the reforming reactor 2, the coal bed gas 1 mainly composed of methane to be reformed is based on the action of heat under such high-temperature heating and the action of the catalyst 7 filled therein. Steam is reacted as a gasifying agent, and steam reformed to a reformed gas 8 mainly composed of hydrogen, carbon monoxide, and carbon dioxide.
Thus, as water vapor | steam which reacts with the coal bed gas 1, the part accompanying the coal bed gas 1 is used, but when it is insufficient, it is replenished suitably.
As the reforming catalyst 7 for promoting the reaction, a nickel catalyst is typically used. For example, a nickel-supported alumina granular catalyst (particle size: 60 to 80 mesh) is used. Zeolite-based materials can also be used. The catalyst 7 is filled in the reforming reactor 2 as a particle fixed reaction layer, for example.
And the produced | generated reformed gas 8 is taken out to the tank 9 via the pipe line 5, is stored, and is used.
The reforming reactor 2 and the like are as described above.

《Steam reforming reaction of methane》
Next, the steam reforming reaction of methane will be described. In the reforming reactor 2, first, methane CH _4, which is the main component of the coal bed gas 1, is steam reformed by the following chemical reaction formulas 1 and 2.

In the reaction formula of Chemical Formula 1, methane CH ₄ reacts with steam H ₂ O to be steam reformed to carbon monoxide CO and hydrogen H ₂ . That is, in the system of methane gas CH ₄ and water vapor H ₂ O, the enthalpy of the system is increased by applying high temperature, and a mixed gas of carbon monoxide CO and hydrogen H ₂ is generated as the reformed gas 8 by endothermic reaction. The amount of product hydrogen H ₂ (hydrogen H ₂ yield) is minimal.
On the other hand, in the reaction formula of Chemical Formula 2, methane CH ₄ reacts with steam H ₂ O and is steam reformed to carbon dioxide CO ₂ and hydrogen H ₂ . This is the case where a large amount of water vapor H _{2 O} together with works, carbon monoxide CO in the reaction scheme of 1 was also completely modified from 1 Scheme of carbon dioxide CO ₂ and hydrogen by an endothermic reaction A mixed gas of H ₂ is generated as the reformed gas 8, and the amount of generated hydrogen H ₂ (hydrogen H ₂ yield) is maximized.
That is, in the reaction formula of this reduction 2, carbon monoxide CO which is generated by the reaction formula of 1, the shift reaction of the following Chemical Formula 3 is an exothermic reaction, reacts with the water vapor H _{2 O,} carbon dioxide CO ₂ and hydrogen H ₂ are reformed and converted. The reaction formula of the chemical formula 2 is obtained by adding the chemical formula of the chemical formula 3 to the reaction formula of the chemical formula 1.

<Progress of steam reforming of methane, etc.>
Next, the progress of such steam reforming of methane will be described. As described above, steam reforming of methane proceeds according to the chemical formula 1 when the shift reaction is 0%, and according to the chemical formula 2 when the shift reaction is 100%.
However, this is theoretically a limit, and in practice, steam reforming is performed according to an intermediate reaction formula between chemical formula 1 and chemical formula 2 according to the degree of occurrence of chemical shift 3 reaction that reduces the carbon monoxide concentration. In this case, a mixed gas of carbon monoxide, carbon dioxide, and hydrogen is generated as the reformed gas 8.
That is, if the supply of heat is sufficient and methane is completely decomposed into the reformed gas 8 of three gases of carbon monoxide, carbon dioxide and hydrogen, the mole fraction of hydrogen is the lowest in the state of reaction formula 1 To the state of the reaction formula of the best chemical formula 2. Therefore, the hydrogen ratio (vol.%) In the generated reformed gas 8 is 75% to 80% (3/4 to 4/5), and hydrogen is the main component of the reformed gas 8. .

The amount of steam required for such steam reforming is as follows. That is, the theoretically necessary amount of water vapor is 1 to 2 mol (18 g to 36 g) according to the reaction formulas of Chemical Formula 1 and Chemical Formula 2 with respect to 1 mole (16 g) of methane, which is 1.1 times to 2. 3 times.
The actual required amount is usually 1.3 times the theoretical required amount. Therefore, the amount of water vapor actually required is 1.4 to 3.0 times the methane weight. As such water vapor, as described above, the amount accompanying the coal bed gas 1 is used, and when it is insufficient, it is appropriately supplemented.
In addition, the heat quantity H necessary for such steam reforming is as follows. That is, the theoretically required supply heat amount H per 1 mole (16 g) of methane is 206.2 kJ (about 50 kcal, about 3 kcal per 1 g of methane) according to the reaction formulas of Chemical Formula 1, Chemical Formula 2, and Chemical Formula 3. Since an exothermic component of 41.1 kJ is added to the next shift reaction, the minimum is 165.1 kJ (about 40 kcal, about 2.5 kcal per gram of methane). A heat quantity H corresponding to the heat source 6 which is an external system is supplied to the reforming reactor 2.
Methane steam reforming is thus performed.

About steam reforming reaction of ethane and propane
The coal bed gas 1 to be reformed contains methane as a main component, and the steam reforming reaction is as described above. By the way, the coal bed gas 1 further contains a small amount of ethane and a small amount of propane. The steam reforming reaction is as follows.
In the reforming reactor 2, ethane in the coal bed gas 1 is steam-reformed by the following reaction formulas 4 and 5. Further, propane in the coal bed gas 1 is steam reformed by the following reaction formulas 6 and 7.

Ethane C ₂ H ₆ is composed of carbon monoxide CO and carbon dioxide CO ₂ based on the chemical formula 4 (when the shift reaction is 0%) and the chemical formula 5 (when the shift reaction is 100%). is steam reformed into hydrogen H _2, the reformed gas 8 is produced.
Propane C ₃ H ₈ is based on the reaction formula of Chemical Formula 6 (when the shift reaction is 0%) and the chemical formula of Chemical Formula 7 (when the shift reaction is 100%) and carbon monoxide CO and carbon dioxide CO ₂ Steam reforming to hydrogen H ₂ is performed to produce reformed gas 8.
That is, ethane C ₂ H ₆ and propane C ₃ H ₈ are the same as described above for methane CH ₄ , and a mixed gas containing carbon monoxide CO, carbon dioxide CO ₂ , and hydrogen H ₂ as main components is a reformed gas. 8 is generated. In addition, the steam reforming of ethane C ₂ H ₆ and propane C ₃ H ₈ is the same as described above for methane CH ₄ , and thus the description thereof is omitted.
Steam reforming of ethane or propane is performed in this way.

《Action etc.》
The reforming system of the coal seam gas 1 of the present invention is configured as described above. Therefore, it becomes as follows.
(1) The coal seam gas 1 is extracted from the coal seam, guided, and supplied to the reforming reactor 2 via the storage tank 4 of the supply means 3.

(2) The coal bed gas 1 is made of a wet gas accompanied by moisture H ₂ O, contains methane CH ₄ as a main component, and also contains a small amount of ethane C ₂ H ₆ and a small amount of propane C ₃ H ₈ .
A heat quantity H is introduced from the heat source 6 into the reforming reactor 2, and the inside is maintained at 650 ° C. or higher, for example, about 800 ° C.

(3) Therefore, the supplied coal bed gas 1 is reformed in the reforming reactor 2 by reacting with steam H ₂ O based on the action of heat and the action of the catalyst 7 filled therein. The

(4) That is, methane CH ₄ which is the main component of coal bed gas 1 reacts with water vapor H ₂ O according to the reaction formulas of Chemical Formula 1, Chemical Formula 2, and Chemical Formula 3 described above to produce hydrogen H ₂ , carbon monoxide CO. , Steam reforming to a reformed gas 8 such as carbon dioxide CO ₂ .
Ethane C ₂ H ₆ and propane C ₃ H ₈ are also steam-reformed according to methane CH ₄ based on the above-described reaction formulas of Chemical Formula 4, Chemical Formula 5, Chemical Formula 6, Chemical Formula 7, and the like.

(5) The reformed gas 8 thus reformed and generated is supplied to the tank 9 and then provided and used as a fuel and energy source. In particular, hydrogen H ₂ which is the main component of the reformed gas 8 is widely used for various applications.

(6) For example, the hydrogen H ₂ produced in this way is used for coal liquefaction. That is, for example, it is added to a slurry in which oil is added to finely pulverized coal at high temperature and high pressure, so that the polymer-structured coal is used as a low-molecular liquid fuel.
Coal consists of a polymer structure in which polynuclear aromatic rings (cluster units) are connected by short chain hydrocarbons. Such a polymer structure was cut and decomposed by the addition of hydrogen H atoms to reduce the molecular weight. Used to make liquid hydrocarbons.

(7) Now, in the reforming system of the coal bed gas 1, as described above, the methane CH ₄ or the like of the coal bed gas 1 is steam-reformed while utilizing the accompanying water H ₂ O, and thus generated. The reformed gas 8 such as hydrogen H ₂ and carbon monoxide CO can be provided as fuel or the like.
That is, it is possible to provide an energy source far superior to using the methane CH ₄ of the coal bed gas 1 directly as a fuel or the like.

(8) Furthermore, when this reforming system is adopted, hydrogen H ₂ obtained as the reformed gas 8 can be used for coal liquefaction on the spot.
That is, the required hydrogen H ₂ can be immediately supplied at the coal liquefaction site by steam reforming the coal bed gas 1 extracted from the coal bed and guided to the ground. That is, hydrogen H ₂ can be directly supplied to a coal liquefaction factory that is often located in the same coal mine area.

(9) Further, in this reforming system, attention is paid to the fact that the coal bed gas 1 is a wet gas accompanied by a large amount of moisture H ₂ O, and the moisture H ₂ O is actively used for steam reforming. Furthermore, this reforming system is composed of equipment such as a heat source 6, tanks 4 and 9 with the reforming reactor 2 as the center, and the configuration is simple and easy.
Thus, this reforming system is excellent in running cost and equipment cost.

(10) Further, in this reforming system, the methane CH ₄ of the coal bed gas 1 is steam reformed without being released into the atmosphere. This will contribute to the prevention of global warming.

About one example of coal seam gas 1, the measurement data of a component are as follows. This data is the arithmetic average of the sample for dry gas excluding moisture H ₂ O.
Methane _CH 4: 94.4%
・ Ethan C ₂ H ₆
: 1.7%
・ Propane C ₃ H ₈
: 0.3%
・ Oxygen O ₂ : 0.3%
・ Nitrogen N ₂ : 3.1%
Carbon dioxide _CO 2: 0.3%

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration flow diagram for explaining the best mode for carrying out the invention of a coal bed gas reforming system according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coalbed gas 2 Reforming reactor 3 Supply means 4 Tank 5 Pipe line 6 Heat source 7 Catalyst 8 Reformed gas 9 Tank H Calorific value

Claims (5)

  A coal bed gas supply means; and a reforming reactor for reforming the supplied coal bed gas. The coal bed gas is a wet gas accompanied by moisture, and the reforming is performed at a high temperature. A coal bed gas reforming system, characterized in that it is carried out under a catalyst below.   2. The coal bed gas reforming system according to claim 1, wherein the coal bed gas is mainly composed of methane, and the reforming by the reforming reactor is performed by reacting the coal bed gas with water vapor to form a reformed gas. A reforming system for coal seam gas, which is performed by steam reforming, wherein the reformed gas contains hydrogen and carbon monoxide or carbon dioxide as main components.   In the coal bed gas reforming system according to claim 2, in the steam reforming by the reforming reactor, the amount of water actually required is 1.4 times to 3.0 times the weight of the methane. There is a coal bed gas reforming system characterized in that the amount of supplied heat that is actually required is 165.1 kJ to 206.2 kJ per mole of methane.   3. The coal bed gas reforming system according to claim 2, wherein hydrogen of the reformed gas generated in the reforming reactor is used for liquefaction of coal, and liquefied carbonization in which the coal having a polymer structure is reduced in molecular weight. A coal bed gas reforming system, characterized in that it is used for hydrogen.   The coal bed gas reforming system according to claim 2, wherein the coal bed gas contains methane as a main component and also contains a small amount of ethane and propane. A reforming system for coal seam gas, wherein the reformed gas containing carbon dioxide as a main component is subjected to steam reforming.

Images