CN103471977A - Detection system and detection method for detecting gas permeability of coal gangue fill - Google Patents

Abstract

The invention discloses a detection system and detection method for the gas permeability of a coal gangue filling body. The detection system includes a gas cylinder, an air compressor and a mould, and the gas cylinder is connected to a gas mixing box through a pipeline; The air compressor described above communicates with the gas mixing box through a pipeline; the mold is a shell with an open end, and the air inlet of the mold communicates with the gas mixing box through a pipeline, and the pipeline is provided with a barometer and a gas meter; The air outlet is connected to a pipeline, and the pipeline is equipped with a barometer and a gas meter; coal gangue with a certain particle size distribution is installed in the mold, and the mold is sealed by a rubber plug, and a layer of steel plate is arranged outside the rubber plug, and the synchronous jack presses the steel plate. The invention can quantitatively calculate the gas permeability of coal gangue filling bodies with different grades under the conditions of simulating coal gangue filling and mining in the gob area of the high gas fully mechanized mining face, and is suitable for the coal gangue filling mining in the goaf of the high gas fully mechanized mining face. Provide a theoretical basis.

Description

A gas permeability detection system and detection method of coal gangue filling body

technical field

The invention relates to a detection system and a detection method for the gas permeability of a coal gangue filling body.

Background technique

my country's "three downs" (under buildings, under railways, and under water bodies) have a serious problem of pressing coal. At the same time, the discharge of a large amount of coal gangue not only occupies a large amount of land, but also poses a threat to the ecological environment and safety of the ground. The method of coal gangue filling coal mining can not only reduce the discharge of solid waste in coal mines, but also reduce mining subsidence disasters and improve the recovery rate of mine resources. In addition, gas accidents are one of the most serious disasters in coal mines in my country. Analyzing the causes of gas accidents in fully mechanized mining faces, most of them are due to large-scale mining of coal bodies, resulting in the formation of large-area goafs in a short period of time. The roof bears huge mining stress, which leads to a large expansion of cracks in the coal seam, changes in the permeability of the coal body, and causes a large amount of gas to burst out instantly. Especially when the coal seam group is unloaded and mined, the amount of gas gushing out from high-gas mines If it is larger, it will eventually cause the gas concentration in a certain range to exceed the limit, and form a hidden danger of accidents.

It is of great significance to study the gas migration law of coal gangue filling body in goaf of high gas fully mechanized mining face, especially for the study of the gas permeability coefficient of goaf filling body of goaf in high gas fully mechanized mining face. There are few researches on the gas permeability of coal gangue filling body at home and abroad, and there is no corresponding testing method and device for gas permeability testing of coal gangue filling body. Especially in the aspect of simulating the air permeability coefficient of coal gangue filling body in the goaf of high gas fully mechanized mining face, no results related to this study were found after patent search and literature search.

Contents of the invention

In order to solve the above technical problems, the present invention provides a detection system and detection method for the gas permeability of coal gangue filling body with simple structure and convenient operation, which can provide a theoretical basis for coal gangue filling mining in the goaf of high gas fully mechanized mining face .

The technical scheme adopted in the present invention is: comprising gas cylinder, air compressor, gas mixing box, mold and synchronous jack, said gas mixing box is provided with air inlet, gas inlet and gas mixture outlet, The gas cylinder is communicated with the gas inlet of the gas mixing box through a pipeline; the air compressor is communicated with the air inlet of the gas mixing box through a pipeline; the mold is a shell with one end open, The mold is provided with an air inlet and an air outlet; the air inlet of the mold communicates with the mixed gas outlet of the gas mixing box through a pipeline, and the pipeline connecting the air inlet of the mold with the mixed gas outlet of the gas mixing box is provided with an air pressure meter and gas meter; the gas outlet of the mold is connected to a pipeline, and the pipeline is equipped with a barometer and a gas meter; the mold is equipped with a coal gangue filling body, the opening of the mold is sealed by a rubber plug, and a layer of steel plate is arranged outside the rubber plug, and a synchronous jack Press down on the steel plate.

In the gas permeability detection system of the coal gangue filling body mentioned above, the air inlet and the air outlet inside the mold are respectively provided with grids.

In the gas permeability detection system of the coal gangue filling body mentioned above, the gas cylinder and the gas gas inlet of the gas mixing box are connected with a gas gauge and a valve on the pipeline.

In the gas permeability detection system of the coal gangue filling body mentioned above, a barometer is provided on the pipeline communicating between the air compressor and the air inlet of the gas mixing box.

In the gas permeability detection system of the coal gangue filling body mentioned above, a methane concentration detector is installed on the gas mixing box.

In the gas permeability detection system of the above-mentioned coal gangue filling body, a valve is also provided on the pipe connecting the air inlet of the mold and the air mixture outlet of the air mixture box.

In the gas permeability detection system of the coal gangue filling body described above, a valve is also provided on the pipeline connected to the gas outlet of the mold.

A method for detecting the gas permeability of a coal gangue filling body, comprising the following steps:

1) Use the similar gradation method to simulate the ratio of the maximum particle size, the minimum particle size and the average particle size of the gangue gradation, and screen the gangue;

2) Divide the selected coal gangue into several groups;

3) Put a small group of coal gangue into the mold, apply pressure to the steel plate with a synchronous jack, and simulate the working environment of the gangue filling body in the goaf of the coal mine;

4) In the gas mixing box, mix air and 99% gas, use a methane concentration detector to control the concentration of the mixed gas, and then pass the mixed gas through the air inlet of the mold, and wait for the gas to absorb After balancing, measure the air pressure p ₁ and p ₂ of the air inlet and outlet of the mold with a barometer, and measure the flow rate Q of the mixed gas with a gas meter at the same time; and calculate the gas permeability coefficient of the gangue filling body according to the following formula;

$\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 0.2</span>}\mathrm{<span\; class="notranslate">\; \&mu;PQL</span>}}{\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="p"\; filenames="130925162452.png"\; state="\{\{state\}\}">p</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}$

In the formula: k—coal gangue permeability coefficient, m ² ;

μ—absolute viscosity of gas under test temperature conditions, 10 ^-3 MPa·s;

p ₁ , p ₂ —the mixed gas pressure at the inlet and outlet of the mold, MPa;

P—atmospheric pressure, 0.1MPa;

Q—flow rate of mixed gas, m ³ /s;

L—the length of coal gangue filling body, m;

5) Adjust the concentration of gas in the mixed gas, and repeat step 4) multiple times with mixed gas with different concentrations of gas;

6) After measuring the results, pour out the gangue and check the particle gradation of the gangue after pressure is applied;

7) According to steps 3)-6) to conduct experiments on the coal gangue of the remaining groups, the gas concentration in the mixed gas used is the same as that used in the first group of coal gangue experiments in steps 4) and 5). Corresponding to the gas concentration; and use the measured data to calculate the gas permeability coefficient of each group of gangue filling bodies corresponding to the mixed gas with different gas gas concentrations, and compare the gas permeability of different graded coal gangue filling bodies corresponding to the mixed gas with the same gas concentration sex.

In the above gas permeability detection method of coal gangue filling body, the gas concentration of the mixed gas used in step 4) or 5) is: 20%, 35% or 50%.

Compared with prior art, the beneficial effect of the present invention is:

The gas gas released from the gas cylinder of the present invention is mixed with the air compressed by the air compressor in the gas mixing box, and the mixed gas gas is detected by a methane concentration detector; the gas gas is passed through a coal gangue body of a certain pressure; Measure the air pressure p ₁ and p ₂ at the air inlet and outlet of the mold respectively by the barometer, and measure the flow rate Q of the mixed gas passing through the gangue body with the gas meter at the same time; calculate the gas permeability of the gangue filling body; use this The invention can calculate the gas permeability of coal gangue filling bodies with different grades under the condition of coal gangue filling in the goaf of the high gas fully mechanized mining face, and provide a theoretical basis for the coal gangue filling and mining of the goaf of the high gas fully mechanized mining face; The invention also has the advantages of simple structure, easy operation and easy maintenance.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

Fig. 2 is the front view of the mold of the present invention

Fig. 3 is the top view of the mold of the present invention

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figure 1, the present invention comprises gas cylinder 1, air compressor 3, gas mixing box 2, cuboid mold 4 and synchronous jack 5, and described gas mixing box 2 is provided with methane concentration detector 21, air Gas inlet 23, gas inlet 22 and gas mixture outlet 24, the gas cylinder 1 and the gas gas inlet 22 of the gas mixing box 2 are communicated through the pipeline 11; the pipeline 11 is provided with a barometer 111 and valve 112 . The air compressor 3 communicates with the air inlet 23 of the air mixing box 2 through a pipeline 31 ; the pipeline 31 is provided with a barometer 311 . As shown in Figures 2 and 3, the mold 4 is a shell with an open end, and the mold 4 is provided with an air inlet 47 and an air outlet 48; Mixed gas outlet 24 communicates; Pipeline 45 is provided with gas meter 453, barometer 452 and valve 451; The mold 4 is equipped with a coal gangue filling body 42 with a certain particle size distribution, the opening of the mold 4 is sealed by a rubber plug 43, and a layer of steel plate 44 is arranged outside the rubber plug 43, and the synchronous jack 5 presses the steel plate 44. A grid 41 is provided at the air inlet 47 and the air outlet 48 in the mold 4 .

The gas required for the experiment is mixed by the gas released from the gas cylinder 1 and the air extruded by the air compressor 3 according to a certain ratio, and the concentration of the mixed gas is measured by the methane concentration detector 21 . Put the coal gangue into the cuboid mold 4, put the grille 41 at the end of the air inlet 47 in the mold 4 to evacuate the air flow, and seal the mold opening with a rubber plug 43, which is provided with a layer of 14mm thick steel plate 44 outside the mold 4. , and then use the synchronous jack 5 to apply a certain pressure to the steel plate 44, the mixed gas of a certain concentration passes through the gangue body loaded with a certain pressure, and then use the barometers 452, 461 and gas meters 453, 463 to measure the gas of a certain concentration The gas pressure and flow rate of the gas before and after passing through the mold 4.

The coal gangue filling body gas permeability detection method of the present invention comprises the following steps:

1) First, use the similarity grading method to simulate the ratio of the maximum particle size, minimum particle size and average particle size of the gangue gradation, and screen the gangue with a similarity ratio of 1:8 to control the maximum particle size of the gangue at 30mm;

2) Select the particle size range of 30-25mm, 25-20mm, 20-10mm, <10mm and the above four particle size mass ratios are 1:1:1:1, 1:2:3:4 and 4: 3:2:1 divided into 7 groups;

3) Put a small group of coal gangue into the mold 4, put the grille 41 at the air inlet 47 and the air outlet 48 of the mold 4 to make the air flow evenly mixed, and seal the mold 4 with the rubber plug 43, and the rubber plug 43 externally press a layer of 14mm thick steel plate 44, and then apply a certain pressure to the steel plate 44 with the synchronous jack 5, simulating the working environment of the gangue filling body in the underground goaf of the coal mine;

4) In the gas mixing box 2, mix air and 99% of the gas in a certain proportion, use the methane concentration detector 21 to control the concentration of the mixed gas to 20%, and then transfer the mixed gas from the mold 4 The air inlet 47 of the gas inlet is connected, and after the gas is adsorbed and balanced, the air pressure p ₁ and p ₂ of the air inlet 47 and the gas outlet 48 are respectively measured with the air pressure gauges 452 and 461, and the flow rate of the mixed gas is measured with the gas meters 453 and 463 at the same time Q; and calculate the gas permeability coefficient of the gangue filling body according to the following formula:

$\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 0.2</span>}\mathrm{<span\; class="notranslate">\; \&mu;PQL</span>}}{\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="p"\; filenames="130925162452.png"\; state="\{\{state\}\}">p</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}$

In the formula: k—coal gangue permeability coefficient, m ² ;

μ—absolute viscosity of gas under test temperature conditions, 10 ^-3 MPa·s;

p ₁ , p ₂ —the mixed gas pressure at the inlet and outlet of the mold, MPa;

P—atmospheric pressure, 0.1MPa;

Q—flow rate of mixed gas, m ³ /s;

L—the length of coal gangue filling body, m;

5) Adjust the concentration of gas in the mixed gas, and use the mixed gas with gas concentration of 35% and 50% respectively to carry out experiments according to step 4);

6) After measuring the results, pour out the gangue and check the particle gradation of the gangue after pressure is applied;

7) Follow steps 3)-6) to conduct experiments on the gangue of the remaining six groups. The gas concentration in the mixed gas used in the experiment is the same as that used in the first group of gangue experiments in steps 4) and 5). Corresponding to the gas concentration in the gas; and use the measured data to calculate the gas permeability coefficient of each group of gangue filling bodies 42 corresponding to the mixed gas with different gas gas concentrations, and compare the different gradation coal gangue filling bodies 42 corresponding to the same gas gas concentration Permeability of mixed gas.

Claims (10)

1. the detection system of a gangue obturation gas gas penetration potential, it is characterized in that: comprise gas gas cylinder, air compressor, gas mixed box, mould and synchronous jack, described gas mixed box is provided with air inlet, methane gas air intake opening and combination gas gas outlet, and the methane gas air intake opening of described gas gas cylinder and gas mixed box passes through pipeline communication; The air inlet of described air compressor and gas mixed box passes through pipeline communication; The housing that described mould is an end opening, mould is provided with air intake opening and gas outlet; The air intake opening of mould is communicated with the combination gas gas outlet of gas mixed box by pipeline, and the air intake opening of mould is provided with rain glass and gas meter with the pipeline that the combination gas gas outlet of gas mixed box is communicated with; The gas outlet of mould connects a pipeline, and this pipeline is provided with rain glass and gas meter; The gangue obturation is housed in mould, and the opening part of mould is by rubber stopper seal, and rubber plug is provided with one deck steel plate outward, and synchronous jack compresses steel plate.

2. the detection system of gangue obturation gas gas penetration potential according to claim 1 is characterized in that: the air intake opening of described mould inboard and place, gas outlet are provided with respectively grid.

3. the detection system of gangue obturation gas gas penetration potential according to claim 1, it is characterized in that: described mould is cuboid.

4. the detection system of gangue obturation gas gas penetration potential according to claim 1, it is characterized in that: described gas gas cylinder is provided with rain glass and valve with the pipeline that the methane gas air intake opening of gas mixed box is communicated with.

5. the detection system of gangue obturation gas gas penetration potential according to claim 1, it is characterized in that: described air compressor is provided with rain glass with the pipeline that the air inlet of gas mixed box is communicated with.

6. the detection system of gangue obturation gas gas penetration potential according to claim 1, it is characterized in that: described gas mixed box is provided with the methane concentration detector.

7. the detection system of gangue obturation gas gas penetration potential according to claim 1, is characterized in that: on the pipeline that the air intake opening of described mould is communicated with the combination gas gas outlet of gas mixed box, also be provided with valve.

8. the detection system of gangue obturation gas gas penetration potential according to claim 1, is characterized in that: on the described pipeline be connected with the gas outlet of mould, also be provided with valve.

9. the detection method of a gangue obturation gas gas penetration potential, comprise the steps:

1) utilize the ratio of maximum particle diameter, minimum grain size and the mean grain size of method of similar grading simulation gangue grating, gangue is sieved;

2) gangue of choosing is divided into to some groups;

3) gangue of a group is put into to mould, by synchronous jack, steel plate is exerted pressure, the working environment of simulation coal mine gob waste filling body;

4) in gas mixed box, the methane gas of air and 99% is mixed, control the concentration of mixed methane gas with the methane concentration detector, more mixed gas is passed into from the air intake opening of mould, after the gas absorption balance, with rain glass, survey respectively the air intake opening of mould, the air pressure p of gas outlet ₁and p ₂, survey the flow Q of mixed gas with gas meter simultaneously; And calculate the gas permeability coefficient of gangue obturation by following formula;

$k=\frac{0.2\mathrm{\&mu;PQL}}{F(p_1^2-p_2^2)}$

In formula: k-gangue permeability coefficient, m ²;

μ-under the test temperature condition, the absolute viscosity of gas, 10 ^-3mPas;

P ₁, p ₂the mixture pressure of-mould air intake opening and gas outlet, MPa;

P-atmospheric pressure, 0.1MPa;

Q-mixed gas flow, m ³/ s;

L-gangue obturation length, m;

5) regulate the concentration of methane gas in mixed gas, with the mixed gas repeating step 4 of the concentration of different methane gas) repeatedly;

6) after measuring result, pour out gangue, check the grain composition of the rear gangue of exerting pressure;

7) by step 3)-6) gangue of all the other several groups is done to experiment, in the mixed gas of use methane gas concentration respectively with step 4), 5) in the mixed gas that adopts during the experiment of first group of gangue methane gas concentration corresponding; And utilize the data of measuring to calculate the permeability coefficient of the mixed gas of the corresponding different methane gas concentration of each group's gangue obturation, relatively different gradation gangue obturation is corresponding to the gas penetration potential of identical methane gas concentration mixed gas.

10. the mixed gas adopted the detection method of gangue obturation gas gas penetration potential as described as right 9, step 4) or 5), the concentration of its methane gas is: 20%, 35% or 50%.

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