WO2003091534A1

WO2003091534A1 - Method for recovering coal seam by non-combustion gasification at original location and method for recovering organic substance or fossil organic substance under ground by non-combustion gasification at original location

Info

Publication number: WO2003091534A1
Application number: PCT/JP2003/005474
Authority: WO
Inventors: Hitoshi Koide; Kei Tawarada; Sichiro Satsumi; Masao Nako; Hironobu Komaki
Original assignee: Kansai Environmental Engineering Center Co., Ltd.
Priority date: 2002-04-26
Filing date: 2003-04-28
Publication date: 2003-11-06

Abstract

A method for recovering a coal seam, or an organic substance or fossil organic substance under the ground by a process of non-combustion gasification at the original location thereof, which comprises pressing supercritical carbon dioxide from the face of the ground into the coal seam or a rock zone (1) containing the organic substance or fossil organic substance under the ground, to thereby extract volatile components from the coal seam or rock zone (1), and recovering the volatile components to the face of the ground. The method allows the effective use of a coal seam or a rock zone containing an organic substance or fossil organic substance under the ground, without mining and by a non-combustion process, and further with a reduced cost and safety.

Description

Description Non-burning in-situ coal gasification and recovery method and non-burning underground organic matter and fossil organic matter in-situ gasification and recovery method

The present invention relates to a non-combustion type in situ coal seam gasification and recovery method for gasifying and recovering an underground coal seam or an underground rock body containing underground organic matter and fossil organic matter using supercritical carbon dioxide. · Related to in-situ gasification and recovery of fossil organic matter. Background art

In recent years, international oil demand has been increasing further due to the remarkable growth in energy demand in developing countries, mainly in the Southeast Asian regions such as China and South Korea, and it is inevitable that the supply of crude oil will become heavier. Various types of research and development have been conducted on the processing of heavy oil. For example, research has been conducted on lightening of heavy residual oil reforming, hydrocracking, thermal cracking, gasification, solvent deasphalting, etc., and effective use of ultra-heavy residual oil remaining after lightening. . Also, new heavy oil processing technologies such as tar sands oil and oil shale oil are being studied.

On the other hand, since the oil crisis, the use of coal has been strongly desired again, but if it is used as it is as an energy source, technology to prevent environmental pollution is needed. Therefore, coal liquefaction technology and the like have been developed, but large-scale equipment that maintains the state at high temperature and high pressure is required to change from solid to liquid, and the problem of high production running costs is a problem. Yes, at present, the problem is that oil cannot compete with petroleum.

Against this background, research has been actively conducted in recent years on the effective use of heavy oil and coal using supercritical fluids, especially supercritical water. This focuses on the fact that supercritical fluids have both high solubility and properties as a reaction solvent.For example, goinuk lignite / goinuk oil shale oil is used in supercritical water or 20% supercritical water. Treat with a mixed solution containing tetralin, It has been reported that Alten and also gas were recovered (Missal P .; Cane 1 M. Edoe 1 Erdgas Kohle, 109, 6, 1999, p. 270-274, Miwa Shige; supercritical Advanced Fluid Utilization Special Study Group Working Group Activity Results Report (1 995) p. 150).

However, even in the case of treating with a supercritical fluid as described above, there is a problem that a large-scale apparatus for maintaining a high temperature and a high pressure state is required. Another problem is that if coal is to be used again, coal mines that have been closed in many areas must be redeveloped.

On the other hand, focusing on the fact that methane is adsorbed and built into underground coal seams, a technique has been proposed in which carbon dioxide is injected into underground coal seams to recover coal seam methane and fix carbon dioxide gas. Kaihei 6-288171).

However, in this case, there is a problem that only the methane adsorbed in the coal seam is recovered, and the coal seam itself is not used.

In addition, as a method of using the underground coal seam as it is, gasification by igniting the underground coal seam and burning it incompletely is performed in Russia, but it is harmful to the environment such as Ichidani Carbon. There is a problem that it cannot be put to practical use in other areas due to the large amount of such substances. Disclosure of the invention

In view of such circumstances, the present invention provides a non-combustion type in-situ coal seam gasification and recovery method and a non-combustion method that can effectively and efficiently use coal beds or underground rocks containing underground organic matter and fossil organic matter at the lowest possible cost and safely. Method Underground organic matter · Fossil organic matter in-situ gasification It is intended to provide a method of recovery.

As a result of repeated studies to achieve the above objectives, high-purity carbon dioxide formed by the amine method from waste gas from thermal power plants was relatively mild under conditions of 31.1 ° C and 7.39 MPa. With the use of such supercritical carbon dioxide, it is possible to extract and recover volatile components from underground coal seams while burying coal underground. The present inventors have found that they can be immobilized on an underground coal seam, and have completed the present invention. The first aspect of the present invention is a non-combustion type in-situ coal seam gasification and recovery method for gasifying and recovering an underground coal seam, injecting supercritical carbon dioxide from the ground into an underground coal seam. A non-combustion in-situ coal seam gasification and recovery method characterized by recovering volatile components extracted from the coal seam to the ground.

In the first embodiment, the supercritical carbon dioxide is injected into the underground coal seam and infiltrated to extract volatile components, so that the coal seam can be effectively used without mining and in a non-combustion system.

A second aspect of the present invention is the non-combustion method according to the first aspect, wherein the carbon dioxide present together with the volatile component is permeated into the coal seam and fixed. In-situ coal seam gasification and recovery method.

In the second aspect, the volatile components extracted from the coal seam by the injection of supercritical carbon dioxide and present together with the carbon dioxide can be taken out by immobilizing only carbon dioxide in the coal seam, and unnecessary. Carbon dioxide can be fixed underground.

According to a third aspect of the present invention, in the first or second aspect, the volatile component extracted from the coal seam is permeated into the coal seam together with the injected carbon dioxide, and the carbon dioxide is adsorbed on the coal seam. A non-combustion in-situ coal seam gasification and recovery method characterized in that the volatile components are gasified and the hydrocarbon-based gas generated thereby is recovered.

In the third aspect, the volatile components extracted by the supercritical carbon dioxide are gasified by microorganisms in the coal seam, and then recovered as a hydrocarbon-based gas. Becomes

'—A fourth aspect of the present invention is the fourth aspect, characterized in that, in the third aspect, a gasification accelerator that promotes a reaction in which the volatile component gasifies in the coal seam is introduced into the coal seam from the ground. In-situ coal bed gasification and recovery method.

In the fourth aspect, by introducing the gasification accelerator, gasification of volatile components in the coal seam can be promoted, and effective utilization of the volatile components can be promoted.

A fifth aspect of the present invention is the non-combustion in-situ coal seam gas according to the fourth aspect, wherein at least one of a microorganism and an enzyme is used as the gasification accelerator. In the recovery method.

In the powerful fifth embodiment, gasification of volatile components in the coal seam can be promoted by introducing microorganisms or enzymes into the coal seam.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, prior to the recovery of the volatile components extracted from the coal seam, methane adsorbed on the coal seam is recovered. Non-combustion in-situ coal seam gasification and recovery method.

In the sixth embodiment, it takes a long time from the start of injection of supercritical carbon dioxide into the coal seam to the time when volatile components can be recovered.However, by recovering methane at a relatively early stage, Can be used effectively relatively early.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the supercritical diacid is formed such that a crack g is formed in the coal bed when the supercritical carbon dioxide is injected into the coal bed. A non-combustion type in-situ coal seam gasification and recovery method characterized by improving the permeability of carbon.

In the seventh aspect, the supercritical carbon dioxide effectively penetrates into the coal seam from the crack formed in the coal seam, and the volatile component can be effectively extracted.

According to an eighth aspect of the present invention, there is provided: 7. The non-combustion type in-situ coal seam gasification and recovery method according to any one of the aspects 7, wherein sand is injected into the coal seam together with the supercritical carbon dioxide.

According to the eighth aspect which is powerful, by injecting sand together with supercritical carbon dioxide, it is possible to form minute cracks in the coal seam, and when the coal seam is injected at a stage where it is likely to contract, the permeability is maintained. Shrinkage is prevented as it is, and land subsidence due to this can be prevented.

A ninth aspect of the present invention is a non-combustion type underground organic matter / fossil organic matter in-situ gasification and recovery method for gasifying and recovering underground organic matter and fossil organic matter, comprising: Non-combustible underground organic matter and fossil organic matter raw material characterized by injecting supercritical carbon dioxide into the rock body and thereby recovering underground organic matter and fossil organic matter contained in the rock body to the ground In-situ gasification recovery method.

In the ninth aspect, supercritical secondary rocks are added to underground rocks containing underground organic matter and fossil organic matter. Volatile components extracted from underground organic matter and fossil organic matter can be gasified and recovered without mining by injecting carbon oxide and infiltrating to extract volatile components without mining. . ―

According to a tenth aspect of the present invention, in the ninth aspect, the underground organic matter / fossil organic matter strength is a natural buried biological remains and excreta, or these biological remains and excrement are at least pressure, heat and microorganisms. At least one of carbonaceous matter, oily matter, and hydrocarbon generated by a kind of action, or at least one of biomass and organic waste artificially injected into underground cavities and cavities, or a combination thereof Non-combustible underground organic matter and fossil organic matter in-situ gasification and recovery method, which is characterized by being a substance.

In the tenth aspect, naturally buried biological remains and excrement buried underground

, Or at least one of carbonaceous matter, oily matter, and hydrocarbons resulting from the transformation of these biological remains and excrement by the action of at least one of pressure, heat and microorganisms, or artificially injected into underground cavities and cavities Volatile components can be recovered from at least one of biomass and organic waste.

The eleventh aspect of the present invention is the non-combustion method according to the ninth or tenth aspect, characterized in that carbon dioxide present together with the volatile component is permeated into the rock body to be fixed. Method Underground organic matter ・ Fossil organic matter in-situ gasification and recovery method. In the eleventh embodiment, the volatile component extracted from the rock by the injection of supercritical carbon dioxide and fixed together with carbon dioxide alone from the volatile component present together with carbon dioxide is used to fix the volatile component. Can be taken out and unnecessary carbon dioxide can be fixed underground.

According to a twelfth aspect of the present invention, in any one of the ninth to eleventh aspects, a gasification accelerator that promotes a reaction in which the volatile component gasifies in the rock body is introduced into the rock body from the ground. Non-combustible underground organic matter and fossil organic matter in-situ gasification and recovery method characterized by introduction.

In the first and second aspects, by introducing a gasification accelerator, gasification of volatile components in underground organic matter and fossil organic matter can be promoted, and effective utilization of volatile components can be promoted.

According to a thirteenth aspect of the present invention, in the thirteenth aspect, as the gasification accelerator, An in-situ gasification and recovery method for underground organic matter and fossil organic matter, wherein at least one of a microorganism and an enzyme is used.

In the thirteenth aspect, gasification of volatile components in the rock can be promoted by introducing microorganisms or enzymes into underground organic matter and fossil organic matter.

In the present invention, carbon dioxide is relatively easily placed in a supercritical state, and by contacting supercritical carbon dioxide with an underground coal seam, volatile components can be extracted from the coal seam in situ by a non-combustion method. However, since the injected carbon dioxide can be immobilized on the coal seam, only the volatile components can be recovered, and the volatile components can be gasified and recovered by permeating the coal seam. This is realized by the new knowledge of, and is effective in an environmentally friendly manner without mining the underground coal seam or excavating unexcavated deep coal seams without emitting harmful substances like combustion method It has the effect that it can be used. At the same time, carbon dioxide, which is a problem due to destruction of the ozone layer, can be fixed underground.

Underground organic matter and fossil organic matter, such as peat and oil sands, can be gasified into volatile components such as methane gas in the same way as coal, and can be recovered as energy as volatile components using supercritical carbon dioxide. It is. Underground organic matter such as peat and oil sands and fossil organic matter have lower grades than coal, but they are expected to be several tens of times more expensive than coal. It is possible to solve energy problems.

As described above, according to the present invention, supercritical carbon dioxide is injected from above the ground to an underground coal seam or an underground rock containing underground organic matter and fossil organic matter, whereby the underground seawater containing the coal seam or underground organic matter and fossil organic matter is injected. Volatile components can be extracted from the rocks of this area and recovered on the ground, so that in-situ non-combustion systems can safely and inexpensively remove underground rocks containing coal seams or underground organic matter and fossil organic matter. This has the effect that it can be used effectively in a non-combustion system. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a non-combustion in-situ gasification and recovery system according to an embodiment of the present invention. It is a figure showing a schematic structure.

FIG. 2 is a diagram conceptually showing a state of gas recovery using a non-combustion in-situ gasification recovery system according to one embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in more detail.

In the present invention, first, supercritical carbon dioxide is directly injected into an underground coal seam, and the coal is reacted with the supercritical carbon dioxide to extract volatile components.

In this effort, a coal seam refers to a stratum (coal seam) composed of underground coal, and its type is not particularly limited. Examples of the coal bed include bituminous coal, sub-bituminous coal, lignite, lignite, anthracite, etc., but bituminous coal is the most volatile component and is most suitable in the present invention. High pressure is required to obtain supercritical carbon dioxide, and the coal seam itself must withstand the pressure of the injected supercritical carbon dioxide. is there. Therefore, a coal seam with a depth of about 500 to 300 Om, preferably about 100 Om, is targeted. In other words, it is preferable that the depth is large in order to secure a high pressure at which the carbon dioxide becomes supercritical when the carbon dioxide is injected into and penetrated into the coal seam. It should have a depth of 0 Om or more. When the pressure is 40 Om or more underground, the pressure of the bedrock including the coal seam (static rock pressure) is usually 8 MPa or more, so that it can sufficiently withstand the pressure of the supercritical carbon dioxide.

In the present invention, supercritical carbon dioxide is carbon dioxide in a supercritical state, and 99.9% or more of carbon dioxide has a temperature of 31.1 ° C or more and a pressure of 7.39 MPa. A supercritical state is established under the above conditions. To inject supercritical carbon dioxide into a coal seam, it is sufficient that supercritical carbon dioxide is converted at least at the stage of contact with the coal seam, and it is not necessary to convert supercritical carbon dioxide from the ground. Therefore, it is only necessary to exceed the above conditions when injected into the coal seam. Of course, it may be supercritical carbon dioxide from the ground.

In the present invention, by injecting high-purity carbon dioxide at a predetermined pressure and temperature, Inject supercritical carbon dioxide into the coal seam. High purity is at least 99%, preferably at least 99.9%. It is to be noted that supercritical carbon dioxide can be obtained at a high temperature and high pressure even if it is not more than 99%, but it is preferable to use high purity carbon dioxide of not less than 99% because the injection condition becomes severe.

Such high-purity carbon dioxide can be separated and recovered from waste gas from thermal power plants and factories. The separation and recovery of carbon dioxide from such equipment is still performed today, and the recovered carbon dioxide is sometimes dumped into the sea or underground. Carbon dioxide can be used as it is or with a slightly higher purity. In addition, high-purity carbon dioxide can be relatively easily obtained by an amine method of absorbing and recovering amines such as monoethanolamine. In the present invention, a carbon dioxide injection pipe that reaches a coal seam is installed. Then, high-purity carbon dioxide is injected at a pressure and temperature at which the supercritical state is reached at least when injected into the coal seam. The injection conditions differ depending on the depth of the coal seam, etc. For example, when the depth is 500 m, it is considered that the injection pressure is 1 OMPa and the temperature is about 40 ° C. In this case, the injected carbon dioxide is in a supercritical state at the injection point at the same level as the injection pressure and temperature, but at a distance of several tens of meters from the injection point, about 5 MPa and 30 ° C Is expected to decline to In the case of a depth of 100 Om, it is considered that the injection pressure should be 15 MPa and the temperature should be about 50 ° C. In this case, the injected carbon dioxide is in the supercritical state at the injection point, the same as the injection pressure and temperature, and is about 1 OMPa and about 40 ° C even several tens of meters away from the injection point. However, it is expected that the supercritical state is still maintained. Furthermore, in the case of a depth of 300 m, the injection pressure may be 35 MPa and the temperature may be about 100 ° C. In this case, the injected carbon dioxide is in a supercritical state at the injection point at the same level as the injection pressure and temperature, and even at a distance of several tens of meters from the injection point, 30 MPa and 90 ° It is only reduced to about C, and it is expected that the supercritical state is maintained.

By injecting supercritical diacid carbon into the coal bed and infiltrating it as described above, volatile components are extracted from the coal. Although the technology for extracting volatile components such as tar from coal using supercritical carbon dioxide is known, coal is converted to supercritical carbon dioxide to form coal. Large problems that require large equipment that can withstand high temperature and high pressure in order to contact, and that a large amount of carbon dioxide is mixed into the extracted volatile components make it difficult to use the extracted volatile components effectively. was there. However, the present invention adopts a method of infiltrating supercritical carbon dioxide directly into an underground coal seam, eliminating the need for a large-scale device capable of withstanding high temperatures and pressures. Since it can be removed by immobilization on the coal bed, there is an advantage that the recovery of volatile components can be performed relatively easily.

In the present invention, the method of injecting supercritical carbon dioxide into the coal seam is not particularly limited as long as supercritical carbon dioxide is effectively penetrated as much as possible throughout the coal seam. For example, the injection of supercritical carbon dioxide may be performed from a single point or may be performed from a plurality of places. It is preferable to press-fit so as to form a large number of cracks. That is, in the initial stage of carbon dioxide injection, it is preferable to increase the pressure to pulverize the coal seam to form a large number of cracks. It is also preferable to mix sand or the like as necessary to prevent clogging of the cracks, and to allow the carbon dioxide to penetrate into a wide range over a long period of time.

The point of injection of the supercritical diacid fli carbon and the point of recovery of volatile components must be separated by a distance (at least several tens of meters) sufficient for carbon dioxide to be adsorbed and removed from the coal seam. For example, supercritical carbon dioxide may be injected into the deep part of the coal seam to recover volatile components from the shallow part of the same area, or supercritical carbon dioxide may be injected from one end of the flatly extending coal seam. Volatile components may be recovered from the other end of the distant region.If the coal seam is inclined from the deep portion to the shallow portion and extends in a plane, the volatile component is injected at the deep portion and injected into the shallow portion. Is preferably recovered.

Volatile components extracted by supercritical carbon dioxide may be recovered in the state where they coexist with groundwater, or gasified ones may be recovered. In any case, by recovering after infiltrating the coal seam, only the carbon dioxide present in the mixed state is selectively adsorbed and fixed on the coal seam and removed, thereby reducing or removing the carbon dioxide content. Volatile components thus obtained can be recovered. -In addition, the volatile components extracted by microorganisms when penetrating the coal seam Since it is gasified, it is preferable to recover it as a hydrocarbon gas such as methane after gasification. In order to gasify and recover as a hydrocarbon-based gas in this way, it is necessary to infiltrate the coal seam for a long time and then recover it.However, in order to promote this gasification, a gasification accelerator must be removed from the ground. It may be introduced.

Here, gasification promoters are microorganisms and enzymes that decompose and gasify volatile components such as tar, and are anaerobic microorganisms that can operate at relatively high temperatures, such as Metnanobacterium 丄 'hermoautotrophicum and Methanogenic bacteria such as Methanococcus Jannaschii are preferred. Anaerobic microorganisms other than methanogens play a supplementary role of methanogens, and cannot produce methane but produce intermediate-stage organic acids and hydrogen. Bacteria group to be used.

The method of introducing the gasification accelerator is not particularly limited, and may be present so as to be in contact with the extracted volatile component, and may be introduced using a carbon dioxide injection pipe, A separate injection tube may be provided for introduction.

Further, in the present invention, there is an advantage that methane naturally adsorbed in the coal seam can be obtained until a volatile component, particularly a hydrocarbon-based gas in which the volatile component has been gasified, can be recovered. . In other words, after the introduction of supercritical carbon dioxide, it takes a relatively long time until volatile components, especially hydrocarbon gas, can be recovered. This has the advantage that the supply of useful gas can be started relatively early.

When the hydrocarbon-based gas obtainable by the method of the present invention is estimated as the amount of methane, for example, assuming that it is equivalent to the coal of the Ishikari Coalfield in Hokkaido, which has a large amount of methane adsorption, in the recovery of the initially adsorbed methane per ton of coal, Although the maximum amount of methane is 12.5 cubic meters, the amount of methane is estimated to be about 5334 cubic meters per tonne of coal, considering that it is then extracted with supercritical carbon dioxide and gasified and recovered. Since it can be estimated that methane can be recovered, there is an advantage that it is possible to recover methane more than 40 times compared to the recovery of adsorbed methane alone.

'Furthermore, since the carbon dioxide selectively adsorbed on the coal seam is methanated by thermophilic methane-producing bacteria after a long period of time, the carbon dioxide injected underground is converted to methane. Can be collected sequentially.

In addition, when the volatile component is continuously extracted by the method of the present invention, there is a possibility that the coal seam may contract and land subsidence may occur. In such a case, sand may be mixed with the injected carbon dioxide to introduce sand into the coal seam. Sand fills the gaps in the coal seam to prevent the coal seam from shrinking, but the cracks remain open for carbon dioxide to penetrate, so that the permeation is maintained and ± Yanban settlement is prevented. It works. As described above, in the method of the present invention, supercritical carbon dioxide is introduced into a coal seam to gasify coal into volatile components such as methane gas and collect it. In addition to coal, peat, oil sand, oil shale, It is applicable to gasification of fossil organic matter into methane, such as underground organic matter such as gas siere and garland oil field.

Here, the underground organic matter / fossil organic matter to which the method of the present invention can be applied is formed by burying the remains of living things and excrement deep underground. In other words, if the remains and excrement of living things accumulate on the bottom of the sea or lake with sand and mud, and gradually become buried deep underground, the pressure and temperature will rise, and the fermentation action of microorganisms underground will work, Organic matter, such as human remains and excrement, is gradually transformed into coal and petroleum, and various intermediates are formed along the way. For example, coal is the origin, and peat (peat) is between plants and coal. For example, it exists in wetlands in Hokkaido. Similar ones are called lignite, etc., and are buried in large quantities in young sediments of less than a million years, such as in Sakagyo and Osaka. On the other hand, oil sands and oil shale are those in which oily substances that pretend to be oil accumulate in the gaps between sandstone and shale particles. These oily substances are highly viscous and enter the fine gaps between the rock particles and are in close contact with the particles, so it is difficult to collect them and their use as resources has hardly progressed. Also, in general oil fields, light oil with low viscosity is mostly recovered, but heavy oil with high viscosity such as asphalt is trapped in the gaps between underground rocks, making it difficult to recover. It remains underground and resembles an artificial oil sand. Oil sands are abundant in Canada and Venezuela, and oil shale is abundant in China and elsewhere. In addition, there are many dry fields in old oil-producing countries, but also in Japan. In addition, such fossil organic substances and their altered carbonaceous and oily substances are further decomposed by the action of temperature and pressure microorganisms, decomposed into carbon dioxide and methane, and produced underground. Depending on the methane-producing bacteria that live, it ultimately changes to methane gas and exists underground, but such methane gas and those that are changing to methane gas are called gas sires. Underground organic matter and fossil organic matter to which the method of the present invention can be applied include underground organic matter such as peat, oil sand, oil shale, gas seal, dead oil field and the like, and fossil organic matter. By treating in the same manner as in the injection of carbon dioxide, it is possible to recover as a gaseous component, preferably methane gas. Similarly, organic waste and biomass injected into an underground sand or coal seam can be recovered as volatiles such as methane gas by the same process.

In other words, according to the method of the present invention, gasification that takes a long time in the natural process as it is, supercritical carbon dioxide is injected into the rock body, and volatile matter such as organic matter, carbonaceous matter, oily matter, etc. Can be extracted to promote decomposition by microorganisms.If necessary, gasification can be promoted by adding a gasifier such as an anaerobic bacterium or yeast extract. Volatile components can be enriched in hydrocarbon gas such as methane by selective adsorption of carbon dioxide by substances, and volatile gases such as methane gas can be generated by methanation of carbon dioxide by thermophilic methanogens. Can be obtained by a non-combustion method.

The dead oil reservoir has been storing oil for more than several million years and is the best place to store carbon dioxide.However, since more than half of crude oil that cannot be collected remains, There was some opposition that the injection of Sani-Dani carbon would deteriorate the crude oil and result in resource destruction. However, when the method of the present invention was applied, by injecting supercritical carbon dioxide, the residual crude oil was also gasified as a volatile component. It is possible to recover resources by using them, which has the effect of leading to effective use of resources.

By applying the method of the present invention, it is possible to effectively use resources such as peat, oil sand, oil shale, gas shale, and dead oil fields in addition to coal, and use it as a place for storing carbon dioxide, which has a remarkable effect on the prevention of global warming. .

(Example)

Hereinafter, the present invention will be described based on examples.

FIG. 1 is a diagram conceptually showing a non-combustion in-situ coal seam gasification and recovery system according to an embodiment for carrying out the method of the present invention. As shown in FIG. 1, in the non-combustion in-situ coal seam gasification and recovery system of this embodiment, the volatile component extraction is performed by injecting supercritical carbon dioxide into underground coal seam 1 and extracting volatile components from the coal seam 1. As means, a carbon dioxide injection pipe 11 penetrating from the ground surface 2 to the coal seam 1 and a carbon dioxide injection device 1 2 for injecting carbon dioxide into the coal seam 1 from the carbon dioxide injection pipe 11 at a predetermined pressure. And

Here, the carbon dioxide injecting device 12 injects supercritical carbon dioxide into the coal bed 1 by injecting carbon dioxide of a prescribed purity into the coal bed 1 at a prescribed pressure. That is, it is sufficient that the carbon dioxide is at least in a supercritical state when injected into the coal seam 1, and it is not necessary to be in a supercritical state on the ground. It may be carbon.

For example, when the depth of the coal seam 1 at the injection point is about 100 m, for example, carbon dioxide of 99.9% purity is injected at an injection pressure of 15 MPa and a temperature of about 50 ° C. I do. A gasification accelerator injection pipe 21 and a gasification accelerator injection device 22 are provided adjacent to the carbon dioxide injection device 12. A gasification accelerator such as methane-adhered bacteria is introduced using the gasification accelerator injection device 22. Since the gasification accelerator such as methane-producing bacteria has high resistance, the gasification accelerator injection pipe 21 is omitted, and the gasification accelerator is supplied from the gasification accelerator injection device 22 to the carbon dioxide injection pipe 11. It is also possible to inject.

Here, the supercritical carbon dioxide and the gasification accelerator may be introduced continuously, but generally only intermittently. The introduction conditions, the introduction interval, etc. depend on the type and condition of the coal seam 1. design.

Further, a volatile component recovery pipe 31 and a volatile component recovery device 32 are provided at a relatively shallow position relatively far from the carbon dioxide injection device 12 and the gasification promoter injection device 22. It is assumed that the coal seam 1 exists obliquely from a relatively deep portion where the carbon dioxide injection pipe 11 is inserted to a relatively shallow portion where the volatile component recovery pipe 31 is inserted.

Here, in the volatile component recovery device 32, initially, methane adsorbed on the coal seam 1 is extracted from the coal seam 1 and the volatile components are gasified while permeating the coal seam 1 thereafter. The resulting hydrocarbon-based gas is recovered. In addition, the volatile component recovery device 32 may be a device that recovers a naturally occurring gas or a device that forcibly recovers a gas by suction or the like.

Fig. 2 conceptually shows the procedure of a gas recovery method using such a non-combustion in-situ coal seam gasification recovery system. In the state shown in Fig. 2 (a), natural methane 41 is adsorbed in coal seam 1, and only natural methane 41 released from the coal seam by suction is recovered. Further, supercritical carbon dioxide 42 is introduced from carbon dioxide injection pipe 11. In the state shown in FIG. 2 (b), the introduced supercritical carbon dioxide 42 penetrates into the coal seam 1, thereby extracting volatile components 43 from the coal seam 1 and permeating it. The carbon dioxide 44 is replaced with the natural methane 41 adsorbed on the coal seam and is immobilized on the coal seam 1. Thereby, methane 45 is gradually recovered from the volatile component recovery pipe 31. Furthermore, in the state shown in Fig. 2 (c), the extracted volatile components 43 permeate through the coal seam 1 and are gasified by methane-producing bacteria and the like to become gas 46, and hydrocarbon gas 47 Will be collected as

Claims

The scope of the claims

1. A non-combustion in-situ coal seam gasification and recovery method that gasifies and collects underground coal seams.

A non-combustion type in-situ coal seam gasification and recovery method, which comprises injecting supercritical carbon dioxide from the ground to an underground coal seam, thereby recovering volatile components extracted from the coal seam to the ground.

2. The non-combustion-type in-situ coal seam gasification and recovery according to claim 1, wherein carbon dioxide present together with the volatile component is permeated into the coal seam and fixed. Method.

3. In Claim 1, the volatile component extracted from the coal seam is infiltrated into the coal seam together with the injected carbon dioxide, and the carbon dioxide is adsorbed and immobilized on the coal seam, and the volatile component is removed. A non-combustion in situ coal seam gasification and recovery method characterized by gasifying and recovering the hydrocarbon-based gas generated thereby.

4. The non-combustion type in-situ coal seam gasification and recovery according to claim 3, wherein a gasification accelerator for promoting a reaction in which the volatile component gasifies in the coal seam is introduced into the coal seam from the ground. Method.

5. The non-combustion in-situ coal seam gasification and recovery method according to claim 4, wherein at least one of a microorganism and an enzyme is used as the gasification accelerator.

6. The non-combustion-type in-situ coal seam gas according to any one of claims 1 to 5, wherein the methane adsorbed on the coal seam is collected prior to the recovery of the volatile component extracted from the coal seam. Recovery method.

7. The method according to any one of claims 1 to 5, wherein when the supercritical carbon dioxide is injected into the coal seam, a crack is formed in the coal seam to improve the permeability of the supercritical carbon dioxide. A non-combustion in-situ coal seam gasification and recovery method.

8. The non-combustion in-situ coal seam gasification and recovery method according to any one of claims 1 to 5, wherein sand is injected into the coal seam together with the supercritical carbon dioxide.

9. An in-situ gasification and recovery method for underground organic matter and fossil organic matter that gasifies and recovers fossil organic matter.

Supercritical carbon dioxide is injected from underground into underground organic matter and underground rocks containing fossil organic matter, thereby recovering volatile components extracted from underground organic matter and fossil organic matter contained in the rocks to the ground. Non-combustible underground organic matter and fossil organic matter in-situ gasification and recovery method.

10. In claim 9, the underground organic matter and fossil organic matter are transformed into naturally buried biological remains and excreta, or these biological remains and excrement are transformed by at least one action of pressure, heat and microorganisms. It is characterized in that it is at least one kind of generated carbonaceous matter, oily matter and hydrocarbon, or at least one kind of biomass and organic waste artificially injected into underground voids and cavities, or a composite thereof. Non-combustible underground organic matter · Fossil organic matter in-situ gasification and recovery method.

11. The non-combustible underground organic / fossil organic in situ gas according to claim 9, wherein carbon dioxide present together with the volatile component is permeated into the rock body to be fixed. Recovery method.

1 2. The method according to any one of claims 9 to 11, characterized in that a gasification accelerator for promoting a reaction of the volatile component to gasify in the rock is introduced into the rock from the ground. Non-combustible underground organic matter · In-situ fossil organic matter gasification and recovery method. ―

13. The method for in situ gasification and recovery of underground organic matter and fossil organic matter according to claim 12, wherein at least one of a microorganism and an enzyme is used as the gasification accelerator.