CN108533223B - A system for extraction and utilization of residual coalbed methane in underground goaf - Google Patents

Abstract

The utility model relates to a system and method for the extraction and utilization of residual coalbed methane in underground goafs, which are suitable for the extraction of residual coalbed methane in underground goafs of high gas coal seams with various dip angles. Construct a ground drilling vertically from the ground to the main return airway until it is connected to the return airway, and insert the extraction pipe I into the drilling well. After the mining is completed, the extraction pipe II is pre-buried in the goaf near the return air lane, and a slot is set on it and the slot is protected by a wooden stack. Connect the extraction pipe I and the extraction pipe II. A water ring vacuum pump, a screw booster pump and an adsorption tower are installed in sequence at the surface drilling wellhead, so that the residual coalbed methane in the underground goaf is extracted to the surface through the extraction pipe I and the extraction pipe II, and is improved by the adsorption tower. The concentration of coalbed methane can realize the extraction and utilization of residual coalbed methane in the underground goaf. The invention reduces underground gas accidents. The method has the advantages of low energy consumption, high efficiency, simple and easy implementation, and can generate huge economic benefits at the same time.

Description

A system for extraction and utilization of residual coalbed methane in underground goaf

technical field

The invention relates to a system for extracting and utilizing residual coalbed methane in an underground goaf, which is especially suitable for the extraction of residual coalbed methane in an underground goaf of high gas coal seams with various dip angles.

Background technique

Most of the coal mining in my country is underground, and the mine gas content is generally high. After the underground working face is mined, goafs are formed, and the leftover coal and coal pillars scattered in these goafs will gradually desorb a large amount of methane gas. Methane is the main component of coalbed methane, which is a kind of clean energy and can be used as automobile gas, residential gas and power generation. At present, the method of extracting residual coalbed methane in underground goaf in my country is mainly to arrange conventional buried pipes for extracting coalbed methane in the underground goaf. However, the conventional buried pipe method has a small extraction range and cannot effectively extract the residual coalbed methane in the goaf.

SUMMARY OF THE INVENTION

The object of the present invention is to overcome the deficiencies in the prior art, and to provide a drainage and utilization system for residual coalbed methane in a downhole goaf with high drainage efficiency. It first drills the ground vertically from the ground to the main return airway, and connects with the main return airway, then connects the extraction pipe inserted into the ground drilling with the extraction pipe inserted into the goaf, and then installs it in sequence at the wellhead. Water ring vacuum pump, screw booster pump and adsorption tower are used to realize the extraction and utilization of residual coalbed methane in the underground goaf.

The technical solution steps adopted by the present invention to solve its technical problems are as follows:

a. Vertically construct ground drilling with a diameter of 113-155mm from the ground to the main return airway, so that the drilling and the main return airway are connected;

b. Insert a casing with a diameter of 110-152mm into the ground drilling to 15-20cm beyond the bottom of the ground drilling, and seal the space between the bottom of the ground drilling and the casing with cement to form the sealing section I;

c. Seal the space between the upper part of the surface drilling and the casing with cement to form the sealing section II;

d. Insert a suction pipe I with a diameter of 108-150mm into the casing and fix it;

e. Pre-embed a drainage pipe II with a diameter of 108-150mm at a distance of 3-5m from the return air lane;

f. Set a slot with a length of 30-50cm on the extraction pipe II, and the slot is protected by wooden stacks;

g. Connect the extraction pipe I and the extraction pipe II with a flange;

h. Set the first valve at the wellhead of the surface drilling, set the second valve at the connection between the extraction pipe I and the extraction pipe II, and close the first valve and the second valve;

i. Install the water ring vacuum pump, screw booster pump and adsorption tower in sequence at the wellhead, and open the first valve and the second valve.

Beneficial effects of the present invention:

(1) Solve the problem that the conventional buried pipe drainage method in the underground goaf has a small range of coalbed methane and poor drainage effect. It greatly improves the extraction effect and is easy to popularize and apply on site.

(2) The water ring vacuum pump and screw booster pump installed on the ground are used to efficiently extract the residual coalbed methane in the underground goaf through the extraction pipe I and the extraction pipe II, and the concentration of the coalbed methane is increased through the adsorption tower. Simple, safe and reliable.

Description of drawings

FIG. 1 is a schematic diagram of an embodiment of the present invention.

In the picture: 1. Surface, 2. Surface drilling, 3. Main return airway, 4. Casing, 5. Cement, 6. Sealing section I, 7. Sealing section II, 8. Drainage pipe I, 9 , goaf, 10, return air lane, 11, extraction pipe II, 12, slot, 13, wood stack, 14, flange plate, 15, wellhead, 16, first valve, 17, second valve, 18. Water ring vacuum pump, 19. Screw booster pump, 20. Adsorption tower.

Detailed ways

Below in conjunction with accompanying drawing, the example of the present invention is further described:

As shown in the figure, the ground drilling 2 with a diameter of 113-155mm is constructed vertically from the ground 1 to the main return airway 3, so that it is connected to the main return airway 3. Then insert a casing 4 with a diameter of 110-152mm into the ground well 2 to 15-20cm beyond the bottom of the ground well 2, and seal the space between the bottom of the ground well 2 and the casing 4 with cement 5 to form a sealing section I6. The space between the upper part of the ground well 2 and the casing 4 is sealed with cement 5 to form the sealing section II7. Then, a suction pipe I8 with a diameter of 108-150mm is inserted into the casing 4 and fixed. In the goaf 9, firstly, a extraction pipe II11 with a diameter of 108-150mm is pre-buried at a distance of 3-5m from the return air tunnel 10. A slot 12 with a length of 30-50 cm is arranged on the extraction pipe II11, and the slot is protected by a wooden stack 13. Next, the extraction pipe I8 and the extraction pipe II11 are connected with the flange plate 14, the first valve 16 is arranged at the wellhead 15 of the ground drilling 2, and the second valve 17 is arranged at the connection between the extraction pipe I8 and the extraction pipe II11, And close the first valve 16 and the second valve 17. Then, a water ring vacuum pump 18, a screw booster pump 19 and an adsorption tower 20 are installed in sequence at the wellhead 15, and the first valve 16 and the second valve 17 are opened to efficiently extract the residual coalbed methane in the goaf 9.

Claims (1)

1. A residual coal bed gas extraction and utilization system of an underground goaf comprises a drilling machine and is characterized in that the drilling machine drills a well to the ground, and a drilling well (2) is communicated with a main return airway (3); the casing (4) is arranged in the drilling well (2), and the drilling well (2) and the casing (4) are sealed by cement (5); one end of an extraction pipe I (8) is inserted into the casing pipe (4) and is connected with an extraction pipe II (11) pre-buried in the goaf (9) through a second valve (17), and the other end of the extraction pipe I (8) is located on the ground and is sequentially connected with a first valve (16), a water ring vacuum pump (18), a screw booster pump (19) and an adsorption tower (20);

the diameter of the well (2) is 155mm, the diameter of the casing (4) is 152mm, the diameters of the extraction pipe I (8) and the extraction pipe II (11) are 150mm, the distance between the extraction pipe II (11) and the return airway (10) is 3-5m, the length of the slot (12) is 30-50cm, and the distance between adjacent slots (12) is 30-50 m;

the coal bed gas extraction method comprises the following steps:

a. vertically constructing a ground well from the ground (1) to the main return airway (3) to ensure that the well (2) is communicated with the main return airway (3);

b. inserting a casing (4) into the drilling well (2), and sealing the space between the bottom of the drilling well (2) and the casing (4) by using cement (5) to form a hole sealing section I (6);

c. sealing the space between the upper part of the well drilling (2) and the casing (4) by using cement (5) to form a hole sealing section II (7);

d. an extraction pipe I (8) is inserted into the casing pipe (4) and fixed;

e. an extraction pipe II (11) is pre-buried at one side of the goaf (9) close to the return airway (10);

f. a slot (12) is arranged on the extraction pipe II (11);

g. the slot (12) is protected by a wood stack (13);

h. connecting an extraction pipe I (8) with an extraction pipe II (11) by using a flange plate (14);

i. arranging a first valve (16) at a wellhead (15) of the well (2), arranging a second valve (17) at the connection part of the extraction pipe I (8) and the extraction pipe II (11), and closing the first valve (16) and the second valve (17);

j. a water ring vacuum pump (18), a screw rod booster pump (19) and an adsorption tower (20) are sequentially installed on a well head (15), a first valve (16) and a second valve (17) are opened, and residual coal bed gas in a goaf (9) is efficiently extracted.

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