RU2390634C1 - Procedure for complex development of coal deposit - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: procedure for complex development of coal deposit refers to mining, particularly to complex development of coal deposit with underground gasification of coal and can be implemented for extracting products of underground gasification of coal and heat carrier with specified parametres; it also can be implemented for associated extraction of selenium. Producer gas exhausted from a borehole is first cooled to temperature not below temperature of gaseous selenium condensation; also there is produced heat power for a heat supplying system. Further gas is quickly cooled with a coolant to a temperature below the temperature of gaseous selenium condensation. Thus there is produced stripped gas, amorphous forms of selenium, selenious acid and waste coolant; selenium and selenious acid are sent to utilisation, while waste coolant is sent to reduction and repeated usage. Ice (H₂O), dry ice (CO₂) or their mixture can be used as coolants.

EFFECT: increased efficiency of development due to associated extraction of selenium, and reduced adverse effect to environment.

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Description

The present invention relates to mining, in particular to the integrated development of a coal deposit during underground coal gasification, and can be used to produce underground coal gasification products, a coolant with specified parameters and as a way of associated mining of selenium.

A known method of integrated development of a coal field, including dividing the field into blocks, drilling degassing and drainage wells, preliminary degassing of coal seams and underground gasification of coal, with the issue to the surface; formation degassing products and coal gasification [1]. The disadvantage of this method is that many useful and toxic components, in particular selenium and its compounds [2], in the process of underground coal gasification go into a gaseous state and are not captured and recovered in the future, thereby reducing the efficiency of developing a coal deposit and polluting the environment.

The closest analogue adopted as a prototype is a method for integrated development of a coal field, including drilling a system of hydraulically coupled wells, performing hydrodynamic and fire effects through them on a coal seam, producing crude generator gas, cooling it to a temperature below the condensation temperature of the components included in the composition of the raw gas, and obtaining other useful components together with purified gas [3].

The disadvantage of the prototype is that during underground gasification of coal, selenium, which is part of coal seams, goes into a gaseous state and leaves wells with products of underground coal gasification in the form of selenium and its oxides. Selenium and its oxides are valuable chemical components that are part of underground coal gasification products, on the one hand, and toxic, on the other. The prototype does not allow selenium as a valuable component to be isolated from underground coal gasification products and to purify these products from selenium and its oxides as toxic components.

This drawback reduces the effectiveness of integrated development of a coal deposit and does not reduce the harmful effects on the environment.

The aim of the invention is to increase the efficiency of integrated development of a coal deposit due to the associated production of a valuable component - selenium and to reduce the harmful effects on the environment by cleaning the products of underground coal gasification from the toxic component - selenium.

This goal is achieved by the fact that in a method for the integrated development of a coal field, including drilling a system of hydraulically connected wells, performing hydrodynamic and fire effects through them on a coal seam, producing crude generator gas, cooling it to a temperature below the condensation temperature of the components that make up the crude gas, and obtaining, together with purified gas, other useful components, upon leaving the well, the generator gas is cooled to a temperature not lower than the temperature nsatsii gaseous selenium and its oxides to yield thermal energy for the heating system; then it is rapidly cooled with a refrigerant to a temperature lower than the condensation temperature of gaseous selenium and its oxides, whereby purified gas, amorphous forms of selenium, selenic acid and spent refrigerant are obtained; then selenium and selenic acid are sent for disposal, and the spent refrigerant is sent to recovery and reuse, moreover, ice (H ₂ O), dry ice (CO ₂ ) or a mixture of them can be used as a refrigerant.

The method is illustrated by the primary processing scheme of underground coal gasification products.

The method of integrated development of a coal field can be implemented as follows. Well 1 by a pipe 2 is connected to a heat exchanger 3 included in the heat supply system through pipelines 4 (T2) and 5 (T1). The gas outlet of the heat exchanger 3 by a pipe 6 through the cover 7 is rigidly connected with the inner space of the cyclone 8. The cover 7 of the cyclone 8 is made in the form of a circle, the diameter of which is much larger than the outer diameter of the cyclone 8. In the peripheral part of the cover 7, a loading device is made including a screw feeder 9 and hopper 10. A rotating cone 12 is attached to the outer edge of the lid 7 by means of a bearing 11, the opposite edge of which is connected to the lower part of the cyclone 8 by means of a bearing 13. In the middle part, a rotating cone 12 by means of a gear wheel 14 and a reducer 15 is connected to the drive 16. The gas outlet from the cyclone 8 through the cover 7 is made by a Central pipe 17, in which a vacuum is created by means of a smoke exhauster 18. The gas exit from the space between the cyclone 8 and the cone 12 is made in the form of a pipe 19. In the lower part of the cyclone a funnel with a pipe 20 is made.

The scheme of the primary processing of gaseous products of underground coal gasification works as follows. Hot products of underground gasification through pipeline 2 enter the heat exchanger 3, where they give part of the heat to the water of the heating system T1-T2. With a reduced temperature (not lower than the condensation temperature of selenium vapor and its oxides), the products of underground coal gasification through pipeline 6 enter the inner space of cyclone 8 tangentially, i.e. tangent. Due to the tangential inlet, the gas flow in the inner space of the cyclone is twisted, clinging to the wall of the cyclone.

By means of the hopper 9, through the hopper 10, the refrigerant, for example crushed ice (H ₂ O), dry ice (CO ₂ ) or a mixture thereof, which is uniformly distributed over the outer surface area through the rotation of the cone 12, is uniformly fed into the space between the cyclone 8 and the rotating cone 12 cyclone 8. Due to the low temperature of dry ice, the wall of cyclone 8 is very cooled. In this regard, the gas stream rotating in the inner space of the cyclone 8 is also cooled to a temperature below the condensation temperature of selenium and its oxides. Selenium and its oxides will pass from the gaseous form to the amorphous (powdery, colloidal, vitreous) forms of selenium. Together with selenium, condensation of water vapor will occur on the cyclone wall; part of selenium and its oxides will dissolve in water with the formation of selenic acid. Selenium and selenic acid due to gravity will begin to flow down the wall of the cyclone to the lower part and through the pipe 20 can be removed from the cyclone. Then selenium is isolated from selenic acid. Purified from selenium and its oxides and the cooled gas stream by the exhaust fan 18 is drawn from the inner space of the cyclone and sent through the gas pipeline 21 for use as a fuel or chemical feedstock.

Dry ice in the space between the cyclone 8 and the rotating cone 12 from contact with the cyclone wall evaporates and is discharged in the form of gas through the pipe 19 for reuse — liquefaction and pressing to form dry ice.

The achieved effect is that the method allows to obtain a valuable substance - selenium or raw materials for its production, and also allows you to clean the products of underground gasification of coal, and therefore the products of their combustion, from the toxic substance, which is selenium and its oxides. That is, the claimed method allows to increase the efficiency of integrated development of a coal deposit and reduce environmental stress in the developed region, and this is the purpose of the invention.

Information sources

1. A method of generating electricity for shaftless coal gasification and / or underground coal burning. / RF Patent No. 2100588, publ. 1997.12.27 (analogue).

2. Yudovich Ya.E., Ketris M.P. Toxic impurities in fossil fuels. Ekaterinburg: Ural Branch of the Russian Academy of Sciences, 2005, p. 494.

3. Kreinin EV Is an environmentally friendly coal-energy complex possible. / Coal, 1-2008, p. 38-40 (prototype).

Claims (1)

A method for the integrated development of a coal field, including drilling a system of hydraulically coupled wells, performing hydrodynamic and fire effects through them on a coal seam, producing crude generator gas, cooling it to a temperature below the condensation temperature of the components that make up the raw gas, and producing it together with purified gas of other useful components, characterized in that upon leaving the well, the generator gas is cooled to a temperature not lower than the condensation temperature gaseously about selenium and its oxides, in this case they receive heat energy for the heat supply system, then it is quickly cooled with a refrigerant to a temperature below the condensation temperature of gaseous selenium and its oxides, and purified gas, amorphous forms of selenium, selenic acid and spent refrigerant are obtained, then selenium and selenic acid is sent for disposal, and the spent refrigerant is sent to recovery and reuse, and ice (H ₂ O), dry ice (CO ₂ ), or a mixture thereof can be used as a refrigerant.

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