IL252692A - Method for energy recovery through combustion in-situ of solid fuel - Google Patents

Description

"METHOD FOR ENERGY RECOVERY THROUGH IN-SITU COMBUSTION OF SOLID FUEL" The present invention relates basically to the field of underground coal combustion, in particular to the combustion of coal and other organic materials contained in suspended or abandoned underground mine workings, in order to generate thermal energy and to prevent accidental underground fires.

This proposal relates, in the first place, to regions whose activities have been underground coal mining for many years. Infrastructure, business activity and social life of the population of these regions were due to the main direction of their activities - coal mining, coal delivery to the consumer, ensuring the required quality of this product. The termination of the activities of these regions led to a sharp decline in the employment of the population and a decline in its well-being. At the state level, there appeared a threat of hopelessness of life in such regions and the growth of social tension in them. It is possible to improve the situation radically in previously successful coal-producing regions if their population is provided with heat in the broadest sense of the term. For example, by constantly providing the thermal energy obtained from burning the remaining coal reserves in the bowels, which are usually about half of the coal mined before and delivered to the surface.

It is important to understand that if the provision of regions with energy will be made from own resources within a time sufficient for their reorientation to a new area of activity, then it will be possible to improve the living and employment conditions of the population. In addition, the invention contains an environmentally important opportunity to prevent catastrophic underground fires that suddenly occur in closed mines due to the remaining coal in them.

It should be noted that the fact that there are a large number of patents, inventions and scientific publications in the field of obtaining and using energy from in-situ incineration of underground coal deposits testifies about the considerable interest in this problem, and first of all from the point of view of its ecological, economic and social significance.

Such publications include, for example, the patent of Yanko Stanislaw et all. in patent application UA68703 (A), they describe a method for thermal energy, consisting of laying the crosscuts, which open the coal seams, burning out of the coal seams and delivering hot gases to the surface. In another patent application, UA68702 (A) Yanko Stanisl av et all. also describe a method for producing thermal energy in underground coal seams combustion. It consists of drilling holes from the surface to the coal seam for the air inlet and gas exhaust, delineation of coal areas by means of joints, ignition of coal through inlet air openings and injection of hot gases to the surface through outlets. With these connections, the contoured area is formed between the air inlets holes and is located along the contour of the polygon, with coal leaving the virgin land between the air inlet holes and the gas outlet holes.

Robert F. Chaiken, in his patents US4,387,655, US5,368,105 and CA1155301 describes a method for recovering energy from wasted coal that is buried underground. The method includes the steps of creating at least one channel through the wasted coal, igniting the wasted coal in this channel, subjecting said wasted coal to etching in at least one of said channel to a negative pressure applied at a predetermined point, combining the waste coal, in at least one of said channel, with an air source remoted from said preselected zone, whereby air penetrates through the flammable coal to combust it to produce gaseous products of combustion, which are then output from said zone. Hot combustion gases further are fed into the heat exchanger t0 EXUBCI heat energy.

US8776518B1: S. Das in his patent US8776518 describes a method of producing electricity comprising the in- situ combustion of fossil fuels and the subterranean separation and recovery of nitrogen from combustion gases.

US 3563606A Describes a stepwise method of burning coal by creating a series of passages from the surface to the coal seam with the formation of combustion chambers within the reservoir and the possibility of moving the combustion zone with the ends of these passages by using one of these passages to supply air to each subsequent passage, which is also used to remove products of combustion previously formed in the previous passage.

WO2012109711A1 The invention describes a device for underground ignition of a coal seam containing an ignition system, a positioning system, a sensor and a controller. The device allows the ignition of a coal seam from the well channel, which is a flexible pipe that allows the ignition device to be located in the required place in the well channel.

US44361S3A Described is a method of controlled thermal connection of an injection well and a production well, which is a continuation of the inclined - horizontal part of the injection well. The oxidizer, in stoichiometric proportions, enters the combustion zone under pressure through an injection well, which ensures the movement of the combustion zone in the predicted direction.

US 4010801A Describes a method for underground gasification of coal by the method of its incomplete combustion. This ensures the receipt of combustible target gaseous products, depending on the pre-selected temperature and pressure, which allows to generate the generated heat, which can be converted to other forms of energy.

With all the variety of methods for underground coal combustion, they do not separately identify or simply lack an estimate of the amount of energy necessary for the long-term provision of heat to regions previously occupied by traditional coal mining.

From the above, the conclusion follows that the process of burning coal is multifactorial, depending on the conditions of its occurrence in the underground space, as well as additional methods ensuring stability and maintaining the required stoichiometry with the necessary quantity (volume) of air supplied to the zone of the firewall.

Most of authors note that the process of underground coal combustion (UCC) is influenced besides geological features of the occurrence of coal, other factors such as the presence of subsurface water in the bowels, cracks in the soil and roof of seams of the mine workings, rock composition and the presence of voids in it, geotectonic features of the occurrence of coal, rocks soil and roof concrete mine workings, etc. One of /02/2018 the most important of them is the strength of the "roof" of underground workings, in which the coal seam is burned. At the same time, the analysis of methods aimed at maintaining the UCC process shows that their main task is to deliver air (oxidant) to the firing zone.

. Many published inventions are devoted to methods of controlling the combustion process or the effect on its course, the ultimate goal of which is to deliver air to the zone of fire processing. A common drawback of the known methods is the apparent instability of the UCC process that is carried out on them, primarily because of the lack of a precise location in real time of the combustion site. This occurs as a result of the caused by its (the burning site) not predictable destruction, which hinders the delivery of the oxidant to the combustion zone, which is carried out, as a rule, from the surface.

In the mentioned inventions for the utilization of coal combustion products in situ, the Consumer of the productive gases is also not specified, which means that there is no data for a real economic evaluation of the project carried out on their basis.

In my understanding, the main consumer of heat should be recognized as the population of regions that previously mined coal. Due to the cessation of coal mining, which was the main activity of these population, and the lack of alternative, these regions became / become destructive, unprofitable for the states of their location.

The basis for the proposed method is the analysis and results of research carried out by me in this direction in 1983-1988 as a responsible performer, in accordance with the program "Ugllegaz" of the Academy of Sciences of the USSR. These works culminated in a successfully implemented experiment on 3 /02/1018 /02/1018 underground coal combustion near the city of Selidovo, Donetsk region, Ukraine. It was carried out by me with a team of employees in the real conditions of the occurrence of coal at a depth of 90 meters, in a designated area of the canned mine. The combustion process lasted continuously for several months and was artificially stopped for summing up the experiment. Among the results of this and previously conducted bench studies, it was concluded that it is possible to control the course of the underground combustion process not only from the surface, in the vertical direction or at an angle, but also horizontally (manually) from the underground space at a distance and under conditions that guarantee safety of life and health.

SUMMARY OF THE INVENTION According to the first embodiment of the present invention, there is proposed a method for energy recovery through combustion in-situ of solid fuel in canned -[mines with preserved in them the system of drifts, their ventilation, supports for the stable maintenance of the roof and walls of the drifts and other underground infrastructure of the mine space.

This method is provided by group of successive steps.

First, it is determination of at least one mine drifts, in which coal combustion is expected to be carried out.

The next step is determination in at least one previously suspended mines of the place and size of the coal ignition zone in the part of the selected mine drifts that will in particular perform the function conditionally named "hot zone", that is, the zone of coal bed combustion in the initial period of the process underground coal combustion (UCC); The next step is the use of existing and / or creation of additional, at least one cased air intake channel (shaft) from the surface to the burned coal seam.

The next step is using of the existing and / or creating an additional, at least one gas-evacuated casing shaft from the combustion zone of the coal seam to the surface which serves simult aneously as the air suction channel.

The next step is using of the existing and / or creation of a new generation drift where at least one existing and / or additionally created air intake shaft is connected to at least one existing and / or additionally created gas outlet shaft and the passage of air in the space in the direction from the air intake shaft to the gas outlet shaft.

Then, there is arrangement of the first "hot zone" to ensure the completeness of combustion, coal ‘n it in the air coming there from the surface in the suction mode, through the available air intake shaft; 4 The next step is possible separation of the "hot zone", with the help of fire-resistant, air-flowing curtains, used as partitions, localizing the combustion process in several zones. The first of which is both the ignition and the start zone of the process (UCC). This division promotes more intensive warming of the roof rock, as a result of which its subsidence occurs more smoothly, and the space formed from larger pieces of 15I02I2018 rock facilitates the entry of air into the combustion zone.

The next step is ignition of the "hot zone" of the coal seam in the selected location at the source of the above-mentioned gas outlet additional cased drift. At the same time, the initial sizes of the "hot zone" are determined by the geology of the coal occurrence and the measures to ensure the controllability of the process (UCC) moving towards the air flow for the time necessary to equip the "cold zone" to transfer it to a subsequent "hot" zone; Then, there is creation of the first, conventionally called "cold zone", which is a production area behind the "burning zone", spaced from it at a distance sufficient to continue the stable burning of coal there /02/2018 and separated by curtains from heat-resistant mesh fabric.

The next step is preparation of the next "cold zone" space for its transfer, in turn, to the subsequent "hot" one. This preparation, like the previous one, is carried out, if necessary, during the time of moving the front of the firewall, as it approaches the "cold zone" side, towards the intake air flow.

The next step is protection / separation of at least one "hot zone" from the other, using fire- refractory curtains of heat-resistant mesh fabric, for example, from graphite fiber, freely passing air to the combustion focus of coal, which allows hot combustion gases (productive gases) to flow through a gas outlet 15I02I2018 shaft into at least one heat exchanger to extract thermal energy from them.

The next step is the repetition of each of the following steps as similar to the previous one until the planned completion of the planned coal mining in the underground space of the selected mine.

According to this embodiment of the present invention, the ignition of the "hot zone" of the coal seam is carried out at the source of the gas escaping additional cased drift at a predetermined location located 5 - 50 meters to 500 meters from said source.

Further, according to the embodiment of the present invention, the combustion of coal in a selected space of about 500 to 1000 meters is maintained by alternating movement of the combustion front from one "hot zone" to another prepared by a "cold zone" of the same approximate extent, in the direction from said at least one available and / or additionally prepared gas outlet shaft to the side of at least one available and / or additionally prepared air intake shaft. 16/03/2018 /02/2013 L Further, according to embodiment of the present invention, in order to continuously extract heat energy from the production gases, in the space of said at least one available and / or several additionally prepared gas outlet production shaft, there are mounted from additionally one to, at least 3 -4 heat exchangers, and in the same place, in the area where they are located, equipment is installed purposely their emergency connection to the existing central heating supply line in the event, for example, of Force Majeure circumstances and also, If necessary, afterburning of productive gases..

.. Further, according to embodiment of the present invention, the mobile fire-resistant screens (firewalls) with the possibility of their remote movement along the surviving rails or along the rails of the corresponding drift of the canned mine. These firewalls act as an additional protection of the roof of the drift from its unordered collapse and dense sleep and help the best penetration of air into the combustion zone. Thus, they contribute to a more stable combustion of coal in the "hot zone".

The mobile firewalls, made in the form of screens of flre-resistant material, are remotely moved along rails or along the rails of the corresponding drift of the canned mine by means of unmanned vehicles remotely controlled both from the surface and inside the shaft, the most ensuring the flow of air to the source of combustion. Thereby there is created a hollow space behind the combustion front of the coal seam, in height and the volume corresponding to the trolleys moving along the rails of this drift and along a length equal to about 500 meters to about 2000 meters in the direction of coal combustion. ._ Finally, in order to continuously extract heat energy from the production gases, an additional casing of the existing gas outlet production shaft is performed, as well as the creation of at least one additional thermo-/corrosion— resistant channel shaft as reserve, with the possibility, if necessary, of afterburning of productive gases before their transfer to heat exchangers, or replacement of the heat exchangers themselves.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross sectional view of a canned mine and coal combustion zone with gas outlet shaft and air supply shaft, according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION The most preferred embodiment of the present invention will be described below with reference to the drawing.

Underground coal combustion (UCC) is a technological process consisting of the combustion of an ‘underground coal seam, as a result of which, as a final product, hot gases are formed that do not contain /02/1018 /021201: 16I03I2018 ‘hydrocarbons in their composition. The gas thus obtained is also called a productive gas. The productive gas as a heat carrier is converted into hot water in the heat exchanger through which it passes. Water is used as a coolant, for example, for heating residential buildings, greenhouses, hotels, railway stations, non—residential premises and other purposes.

The invention is explained in the drawing of FIG. 1.

FIG. 1 illustrates a canned mine 10 and a longitudinal section of one of the mine drifts 12 located at least 90 meters from the surface of the ground 14. Drift 12 has a roof with support 16 that keeps rocks 18 from falling into this drift. Inside the mine, there is coal seam 20 with its own roof 22. Mine drift 12 is connected to at least one cased air intake channel (shaft) 24 supplying air from the shaft surface to this mine drift 12. Gas q outlet channel (shaft) 26 draws the production gases from drift 12 to the surface, passing them through at least one heat exchanger 28. In addition to one main heat exchanger 28, there are three additional heat exchangers 28in shaft 26. Ventilation system 30 with pumps exhausts the production gases from the gas one shaft 26, accelerating their exit from drift 12. Ignition zone 32 of coal seam 20 is located near the mouth of gas outlet shaft 26, at a distance of 5 -500 m from it. Soil 34 is located under coal seam 20. Air space 36 between roof 16 of drift 12 and roof 22 of coal seam 20 is used throughout the entirety of coal seam 20 to connect at least one existing and / or additionally created air intake passage (shaft) 24 up to at least one available and / or additionally created venting channel (shaft) 26 and for passage of air in said space in a direction from air intake shaft 24 to gas outlet shaft 26. Mine’s 10 drift 12 is divided into several zones by means of fire-resistant, air-penetrating curtains 38 made of heat-resistant mesh fabric, for example, of graphite fiber.

F The protection of at least one of burned coal block may be carried out also by means of mobile firewalls 39, made in the form of screens of fire-resistant material. Firewalls 39 are remotely moved along the rails of the corresponding drift 12 of the canned mine by means of unmanned vehicles remotely controlled both from the surface and inside the mine 10.

L * Coal seam 20 is combusted in direction 40 from the gas outlet shaft 26 to air intake shaft 24. In- canned mine 10, other mine drifts 42 and auxiliary drifts 44 located with the option of connecting with auxiliary drifts of adjacent mine drifts may be located, apart from contemplated mine 12. The latter may have ": their canned additional air intake channels 46.

The process of underground coal combustion (UCC) is further illustrated in detail in the example of the “scheme of FIG. 1.

/Ozlzom ’ First of all, the location and size of coal ignition zone 32 is determined in that part of the selected underground mine 12 that will in particular perform the function conventionally referred to as the "hot zone" 50, i.e., the combustion zone of coal seam 20 in the initial period of the UCC process.

The rational preparation of the selected underground space for the implementation of the UCC process to provide heat to the region previously occupied by coal mining is based on the results of mine surveying work, including: - evaluation of the remaining coal reserves in the bowels; - assessment of the state of the main and auxiliary mine workings and drifts, allowing to develop a plan and the procedure for carrying out preparatory work; - evaluation of the effectiveness of various methods of influence on the course of the UCC process, as well as its continuation, if necessary, by transferring to a similar adjacent mine.

The next step is to equip the first "hot zone" 50 to ensure the completeness of the combustion, the coal contained therein in the air coming in from the surface in the suction mode, through an additional cased air intake shaft 24. Ignition zone 32 of coal seam 20 is located near the mouth of gas outlet shaft 26, at a distance of S-500 m from it. The dimensions of the "hot zone" are determined by the geology of the occurrence of coal and measures to ensure the controllability of the UCC process by the air moving towards it during the time period necessary for equipping the "cold zone" during its transition to the "hot" zone.

Further, the arrangement of the first, conditionally called "cold zone" 52, which is a space, of mine drift located beyond "hot zone" 50, but is at the same time part of mine drift 12, in which the UCC process is carried out. To provide comfortable or more secure conditions for preparatory work in the "cold zone", in mine drift 12, at some distance from the source of combustion in "hot zone" 50, curtains 38 are made of heat-resistant, for example, carbonaceous material that freely passes air.

One of the factors of a significant influence on the stability of the UCC process is the uninterrupted flow of air into the combustion zone —"hot zone” 50, which in turn depends on the physical condition of the roof rock, which sags as a result of coal seam 20 firing, as well as the rate of its subsidence on soil 34 of the combustion site. with a longer burnout of coal located in "hot zone" 50 and the time for moving the combustion front toward "cold zone", 52 the more the rock of roof 22 is cemented, and the more the dimensions of its smoothly sagging pieces are cemented. Thus, the conditions for the delivery of air to "hot zone" 50 are improved. Installation at a designated location of "hot zone" 50 fire-resistant, air-penetrating curtains 38 of carbonaceous, for example netting, does not prevent the movement of air into the combustion .zone. /03/2013 16I03lI2018 /0!/2018 Then, additionally, at least one burned coal block ("hot zone”) is protected by mobile fire—retardant shields (firewalls) 39 made of a fire-resistant material that can be moved remotely as the front of the fire moves along the rails of the corresponding drift of the canned mine. By this, air is supplied to the combustion zone.

Gaseous combustion products (firing gases) are discharged through the gas outlet channel 26 and used in heat exchange to extract thermal energy from them.

For the same purpose as the use of curtains 38 made of refractory mesh fabric, it is advisable to use mobile firewalls of 39 different shapes in those mine drifts 10, where the rails previously stored in the trolleys were transported. Firewalls 39 perform the function of additional protection of the roof of the generation from dense sleep and help better penetration of air into the combustion zone. They also contribute to a more stable combustion of coal in the "hot zone". Mobile firewalls 39 that move remotely along rails or along rails via unmanned vehicles remotely controlled both from the surface and inside the shaft provide a temperature of at least about 60 ° C behind the combustion front of the respective coal block. Behind these firewalls 39, an empty space is created corresponding to the dimensions of the trolleys moving along the rails or along the rails of this drift, the length of which is ranges from 500 meters to 2000 meters in direction 40 of burning coal.

Further, after the transition of primary "hot zone" 50 to subsequent "cold zone" 52, the space of next "cold zone" 52 is arranged to transfer it to subsequent "hot zone" 50. This preparation, like the previous ones, is carried out for a period of time moving the front of the firewall face in direction 40, towards the air intake shaft 24.

Thus, each subsequent step is similar to the previous one and is carried out until the completion of the planned coal mining in the underground space of selected mine 10. The arrangement of the selected mine for burning coal in it is based on the principle of alternating conditionally called "hot" and "cold" zones 50 and 52, each of which can be separated from the other by several fire-retardant curtains 38 that freely pass through the air.

If necessary, an additional casing of the existing gas outtake shaft is used for the production of productive gases, as well as the creation of at least one additional thermai- and corrosion-resistant channel (drift), with the possibility, if necessary, of after burning of productive gases, before they are sent to heat exchangers 28, or replacement of heat exchangers 28 themselves.

The protection of each subsequent "cold zone" 52 from the heat of the coal produced in the combustion in "hot zone" 50 is affected by fire-proof curtains 38 passing air, used as partitions, placed two at a distance of +/— 5 meters from each other. It also produces additional reinforcement from the heat-resistant material of the walls and the roof of the mine in "cold zone" 52.

F The method of burning coal (in situ) described in this application can be applied both in burning the accumulated mass of urban organic debris and in organizing new places for the accumulation of organic debris for subsequent combustion. 16/03/2018 1510212013 r*-—L’—\ It is obvious that the proposed way of organizing the UCC process, the alternation of "hot" and ''cold’’ zones, will contribute to the realization of this process to a greater extent than in the methods described in the published patents.

The present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, and it should also be understood that the above-described examples are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be constructed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended below claims.

Claims (7)

w--—.ap a- CLAIMS

1. A method for energy recovery through combustion in—situ of solid fuel in canned mines with the existing system of drifts and their ventilation, which is provided by the steps of: a) creating at least one air intake channel into the mine shaft from a surface up to a combustible coal seam; b) creating at least one gas outtake channel into another mine shaft from a combustible coal seam up to surface; c) connecting them with a connective channel along the coal seam towards from said at least one air intake channel up to said at least one gas outtake channel and air incoming into said at least one air intake channel; d) delineation of a combustible coal seam on several separate blocks with leaving of the coal virgins between said air intake channel and said gas outtake channel; e) igniting said coal seam from the side facing said at least one gas outtake channel and maintaining the combustion of the coal by air, incoming into said at least one air intake channel and said connective channel; f) protecting at least one coal burning block by mobile firewalls made in the form of shields made of fireproof material, remotely movable on the rails or along the rails of the corresponding drift of the canned mine, whereby air is induced through said burned coal to produce hot gaseous products of combustion, that are supplied immediately or after of afterburning in heat exchangers to extract thermal energy from them. 17

2. The method of claim 1, wherein the igniting the coal seam is carried out from side facing of said at least one gas outtake channel in preselected place at distance from 5- 50 up to 500 meters from said at least one gas outtake channel.

3. The method of claim 1, wherein the maintaining of the coal combustion is carried out from block to block at a distance of 500 -1000 meters along the prepared coal seam in the direction from said at least one gas outtake channel to at least one air intake channel.

4. The method of claim 1, wherein each of said at least one gas outtake channel is supplied with at least 3-4 heat exchangers to extract thermal energy from hot combustion gases.

5. The method of claim 1, wherein said mobile firewalls, which are made in the form of shields produced of fireproof material, are remotely movable on the rails or along the rails of the corresponding drift in the canned mine by unmanned vehicles, remotely controllable such as from the surface or inside of the mine.

6. The method of claim 5, wherein said mobile firewalls, which are remotely movable on the rails or along the rails by unmanned vehicles, remotely controllable such as from the surface or inside of the mine, provide air supply to the combustion area, while the movement of these mobile firewalls itself is provide creating a 18 temperature of at least 60 ° C behind the coal combustion front of the corresponding coal block.

7. The method of claim 5, wherein by means of said mobile firewalls remotely movable along rails by unmanned vehicles remotely controlled from the surface, there is created a hollow space corresponding to the trolleys traveling along the rails of the given drift and its length is from about‘500 meters to about 2000 meters in the direction of burning coal. Inventors: Q g H‘ 1 Michael KIPNIS 19 ABSTRACT The present invention relates to the field of underground combustion of coal and other organic materials contained in canned mines, in order to generate thermal energy. A group of successive steps provides the proposed method. Firstly there are created or used at least one air intake channel into the mine shaft from the surface up to a combustible coal seam and at least one gas outtake channel into another mine shaft from a combustible coal seam up to the surface. Further, these channels are connected with a connective channel along the coal seam. The next step is delineation of a combustible coal seam on several separate blocks with leaving of the coal virgins between the air input channel and the gas intake channel. Then, there is implemented an igniting of the coal seam from the side facing at least one gas outtake channel and maintaining the combustion of the coal by air, blowing into the at least one air intake channel and the connective channel. Finally, there is being implemented protecting at least one coal burning block by mobile firewalls made in the form of shields produced of fireproof material. The firewalls are remotely movable on the rails or along the rails of the corresponding drift of the canned mine, whereby air is induced through this burned coal to produce hot gaseous products of combustion, which are drawn from mentioned area and utilize in a heat exchange relationship to recover the heat energy therefrom. 20