RU2373397C2 - Method of monitoring coal mine atmosphere - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: this invention refers to the mining industry and in particular, to the method of monitoring of the coal mine atmosphere under the dust and gas factors, as well as natural retarders of the explosiveness of the powder and gas air mixture. This method includes the measurement of the methane concentration, carbonic oxide concentration, concentration of the weighted coal dust, the air temperature and its velocity in the mine. Additionaly absolute humidity of the air and the ash content of the weighted coal dust are measured. The values of the measured parametres and the given relation allow to determine the current real value of the explosiveness coefficient of the mine working and the mine as a whole. It is compared with the explosiveness coefficient required by the Security rules for the specific type of the workings in order to provide the current information as to the explosiveness of the situation as the foundation for managing decisions. The situation is sequentially compared and the tendency of stability or instability of the safe labour conditions of the miners is monitored at the marked velocities of the air in the mine.

EFFECT: possibility to determine more accurately explosiveness coefficient taking into consideration the danger of the interactions of the gas and dust and natural retarders of the explosiveness of the powder and gas air mixture decreasing the danger.

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Description

The invention relates to the safety of the mining industry, and in particular to monitoring the atmosphere of a coal mine by dust and gas factors and natural phlegmatizers of explosive dust and gas mixture. It can be used in coal mines, dangerous for gas and dust.

There is a method of monitoring the mine atmosphere, implemented by the Methane complex, which conducts continuous local and centralized monitoring of the content of methane and hydrogen oxide in the mine atmosphere in order to provide a signal for automatic shutdown of electrical equipment when the maximum permissible concentrations are reached [1].

The disadvantage of this method is that it does not take into account the total hazard of gas and coal dust, which meets the law of expoid dependence with an exponent less than 1 for the lower explosive limit (LEL) of a dust-gas mixture [2] as more dangerous than that described by Le Chatelier’s law, and also do not take into account the influence of air humidity and dust and ash ash suspended dust as natural phlegmatizers of explosive dust and gas mixture [2].

Known gas monitoring system M1 company FHF Bergbautechnik GmbH & Co [4], which provides monitoring of methane, carbon monoxide, temperature, pressure, air flow and dust formation in mines hazardous for gas and dust to ensure continuous monitoring of gas and dust situations in the atmosphere of the mine, as well as temperature and air flow for comparing them with standard values and issuing warning signals in case of unacceptable deviations of the controlled parameters.

The monitoring drawback is that it does not take into account the increased danger of an explosion due to the combined action of methane and carbon monoxide gases with coal dust and the influence of absolute atmospheric humidity and coal ash ash, as phlegmatizers of the explosiveness of a dust-gas mixture.

A known monitoring method implemented by the automated ore atmosphere monitoring complex (AKMR-M) of the Smolensk production association “Analitpbor”, which continuously measures the volume fraction of methane, oxygen, carbon monoxide in the mine atmosphere, as well as the speed of the air flow in the mine workings in order to provide signals for automatic gas protection, control signals when reaching the maximum permissible values of the volume fraction of carbon monoxide and oxygen and the issuance of information to the control room [5].

The monitoring drawback is similar to the previous complex - the conditions for increasing the explosion hazard of the combined action of methane and coal dust and the influence of absolute air humidity and dust ash as phlegmatizers of explosive dust-methane-air mixture are not taken into account.

The present invention solves the problem of monitoring the mine atmosphere to determine the actual coefficient of explosion safety of the mine and the mine as a whole, taking into account the increasing danger of gas and dust interactions [2] and reducing the risk of natural phlegmatizers of explosive dust-gas mixture, namely the absolute humidity and ash content of coal dust [2 ].

The problem is solved by comprehensive monitoring of the atmosphere of a coal mine, in which the concentration of methane and carbon monoxide, suspended coal dust, the air temperature and its speed in the mine workings are measured and, in addition, the absolute humidity is measured, which is a natural phlegmatizer for the explosiveness of dust-methane-air mixtures, the ash content of suspended coal dust is measured , which is a phlegmatizer of coal dust explosibility, according to the values of the measured parameters, the current actual value oeffitsienta explosion generating shaft and a shaft generally calculated depending on

at

or

x _mNPV = 4.9 + 0.009γ ^2.34 ;

where K is the actual explosion safety coefficient of the mine workings (mine) at the current moment;

x _m - methane concentration,% vol;

- нижний предел взрываемости (НПВ) метана, % объемные;

- lower explosive limit (LEL) of methane,% vol;

c _n is the concentration of suspended coal dust, g / m ³ ;

- нижний предел взрываемости угольной пыли, г/м³;

- lower explosive limit of coal dust, g / m ³ ;

m is an indicator of the degree of interaction between the explosiveness of a dust-methane-air mixture in accordance with the expoidal law;

0.53694; 0.66551 are the constant terms of the indicator m in the corresponding dependencies;

0,12818 - coefficient of the variable term of the indicator m;

4.9 - LEL dry methane,% vol;

0.009 - coefficient of increase in the LEL of methane by atmospheric humidity, (%) / (g / m ³ ) ^2.34 ;

γ - absolute humidity, g / m ³ ;

11.8 - LEL of dry coal dust of Kuzbass coals when the volatiles yield 27.5% and zero ash content, g / m ³ ;

V ^G - yield of volatile substances,%;

0.29 - coefficient of increase in the LEL of coal dust with a change in the yield of volatile substances (g / m ³ ) / (%) ² ;

A ^C is the ash content of coal dust,% (A ^C <65%);

65 - maximum ash content of suspended coal dust, above which the dust does not explode,%;

0.357 - the minimum coefficient of increase in the LEL of coal dust due to atmospheric humidity, (g / m ³ ) / (g / m ³ ) ^1.65 ;

and compare the obtained actual explosion safety coefficient with the explosion safety coefficient required by the Safety Rules (SB) for a specific type of workings in order to provide real-time information about the explosion-proof situation in the mine atmosphere as a basis for making management decisions, and also compare the explosion-proof situation at successive times and monitor the tendency of stability or instability of safe working conditions for miners at marked air speeds in mountain kah.

The total hazard of methane and carbon monoxide gases is calculated according to Le Chatelier's law.

The proposed method for monitoring the atmosphere of a coal mine can be implemented by an integrated system of sensors that provide initial information about the controlled parameters of mine air, and controllers that process the information received on the proposed dependencies.

The block diagram of the complex is presented in figure 1.

The coal mine atmosphere monitoring complex includes a methane sensor 1, carbon monoxide sensor 2, a temperature sensor 3, an air velocity sensor in a mine 4, a suspended coal dust sensor 5, a coal dust ash sensor 6 and an absolute humidity sensor 7, which are distributed through a distribution box 8 is connected to an uninterrupted power supply 9 and controller 10, the outputs of which go to the control signal block 11.

These devices make up the modular block (MB) of the complex, which provides one output. The number of modular blocks MB1, MB2, ..., MBn depends on the branching of the mine workings. Information from the controllers 10 of all blocks through the amplification and signal compression unit 12 is fed to the central control room 13.

In addition to the information received from the sensors, the controllers enter information on the production characteristic (its cross section, percentage of volatiles, the standard explosion safety coefficient, according to the requirements of the safety regulations, and constants included in the calculated dependencies.

The type of information to be determined is determined: from signals to immediately turn off electrical equipment to recommendations for performing non-emergency work, indicating their place on the mine’s mimic diagram and indicating their material and technical support and lead time.

The implementation complex must meet the requirements of a mine especially explosion-proof electrical equipment of the level of PO with the type of explosion protection Ia.

Sensors installed in the mine work are on continuous duty for the life of the mine.

LITERATURE

1. Automation of production in coal mines. / G.I. Bednyak, V.A. Ulshin, V.P. Dovzhenko, etc. - Kiev: "Technique" 1989. - P.219, Complex "Methane".

2. Stefanyuk B.M. The laws of the explosive limits of dust and air environment. / Life safety: environmental, industrial, legal, biomedical and social aspects. // Proceedings of the I International Scientific and Practical Conference, Novokuznetsk, June 8-9, 2005. - Novokuznetsk: NFI KemSU. - S.19-20.

3. Stefanyuk B.M. Coal mine explosion safety factor. 9 sec / Dep. in the scientific library LIU them. I. Frank. Department of handwritten, ancient and rare books. F.P. Maximenka. Inv. No. 3595-26, 1998.

4. Gas monitoring system M1. FHF Bergbautechnik GmbH & Co. KG (Germany). Prospect of the exhibition "Coal and Mining" 2007.

5. Automated control complex for the mine atmosphere AKMR-M. Prospectus of the Coal and Mining Exhibition 2007 FSUE Smolensk Production Association Analitpribor.

Claims (1)

A method for monitoring the atmosphere of a coal mine, in which the concentration of methane and carbon monoxide, suspended coal dust, air temperature and its speed in mine workings is measured, characterized in that the absolute humidity and ash content of the suspended coal dust are additionally measured, and the current actual value is determined from the values of the measured parameters the value of the explosion safety coefficient of the mine workings and the mine as a whole, calculated by the dependence

Where

or

x _mNPV = 4.9 + 0.009γ ^2.34 ;

where K is the actual coefficient of explosion safety of a mine working (mine) at the current moment;
x _m - methane concentration, vol.%;
x _mNVP - lower explosive limit (LEL) of methane, vol.%;
c _p - concentration of suspended coal dust, g / m ³ ;
c _pnpv - the lower explosive limit of coal dust, g / m ³ ;
m is an indicator of the degree of interaction of the explosiveness of the dust-air mixture in accordance with the expoid law;
0.53694; 0.66551 are the constant terms of the indicator m in the corresponding dependencies;
0,12818 - coefficient of the variable term of the indicator m;
4.9 - LEL dry methane, vol.%;
0.009 - coefficient of increase in the LEL of methane by atmospheric humidity, (%) / (g / m ³ ) ^2.34 ;
γ - absolute humidity, g / m ³ ;
11.8 - LEL of dry coal dust of Kuzbass coals when the volatiles yield 27.5% and zero ash content, g / m ³ ;
V ^G - yield of volatile substances,%;
0.29 - coefficient of increase in the LEL of coal dust with a change in the yield of volatile substances, (g / m ³ ) / (%) ² ;
A ^C is the ash content of coal dust,% (A ^C <65%);
65 - maximum ash content of suspended coal dust, above which the dust does not explode,%;
0.357 - the minimum coefficient of increase in the LEL of coal dust due to atmospheric humidity, (g / m ³ ) (g / m ³ ) ^1.65 ;
and compare the resulting explosion safety coefficient with the explosion safety coefficient required by the Safety Rules (SB) for a specific type of workings, in order to provide real-time information about the explosion-proof situation in the mine atmosphere as a basis for making management decisions, and also compare the explosion-proof situation at successive times and monitor the tendency of stability or instability of safe working conditions for miners at marked air speeds in mine workings.

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