RU2452862C1 - Method to prevent explosion of methane-coal-air mixture - Google Patents

Abstract

FIELD: blasting.

SUBSTANCE: method includes operation of an automatic system for prevention of explosion of a methane-coal-air mixture at the earliest stage of its arrival into a mine. Exposure is carried out by inhibition of a methane-coal-air mixture with a fire-extinguishing powder with concentration of at least 300 g/cub.m. The automatic system for prevention of explosion of a methane-coal-air mixture comprises a sensor of methane and modules of powder fire-quenching and is installed in explosive areas of a mine. At the same time, whenever minimum explosive concentration is achieved, the methane sensor generates a signal in the form of an electric pulse to a system of powder discharge initiators - modules of powder fire-quenching, and the fire-quenching powder is ejected into an explosive area. At the same time the methane sensor notifies an operations service about an emergency situation.

EFFECT: higher reliability and efficiency of preventing explosion of a methane-coal-air mixture.

1 dwg

Description

The invention relates to the mining industry, mainly to the coal, and can be used to prevent disasters in mine workings.

A device for inertization of the bottomhole space is known, with the help of which the methane-carbon mixture is treated with an inhibitor, and powder is used as an inhibitor, while the methane-coal mixture explosion prevention system is located in explosive areas of the mine (RU 2301894 C1, published on June 27, 2007).

However, the known method described in the operation of the inertization of the bottomhole space is designed to localize an already completed explosion and its consequences and excludes the possibility of ignition of the methane-carbon mixture by explosion products mixed with an inerting agent, i.e. powder. Therefore, the known method is ineffective for preventing the explosion of methane-coal mixture at an early stage of its entry into the mine.

In addition, the indicated concentration of the inerting agent, which was experimentally established when testing the operation of the bottomhole inertization apparatus in the chamber with a volume of 13 m ³ with a fire extinguishing powder mass of 1 kg, is insufficient to inhibit even minimal explosive methane concentrations of about 5% by volume in air, and even more so maximum explosive methane concentrations - 8.5-9.5%.

Closest to the proposed one is a method of preventing the explosion of a methane-carbon mixture at an early stage of its entry into the mine, the effect being produced by inhibiting the coal-air mixture, and an automatic system for preventing the explosion of a coal-air mixture is used as a source of exposure (RU 2329777 C2, published on July 27, 2008 .).

The disadvantages of this method are the lack of reliability and effectiveness of preventing the explosion of coal-air mixture due to the high inertia of the automatic installation. When the switch is triggered, the control signal is supplied to the solenoid valve, which opens the gate valve of the cylinder with CO ₂ , the gas passes through the pipeline to the container where CCl ₄ is located, a certain time elapses between the signal and the CO ₂ passing through the pipeline, and mixing time is spent and the formation of a stable gas mixture that knocks out the plug and fills the protected volume. It also takes time to fill the volume. In each of these intervals, a spark can occur that will lead to an explosion of the methane-air mixture.

In addition, the gas composition is used for inhibition, and gas due to volatility may be a short time in a certain volume of production. Usually mine workings have gaps and voids, gas will penetrate into them and therefore it is impossible to accurately determine its amount for inhibition.

The objective of the proposed method is to increase the reliability and effectiveness of preventing the explosion of methane-coal mixture.

To achieve this technical result in the proposed method, including the exposure from the source to the coal-air mixture at an early stage of its entry into the mine, the effect is produced by inhibiting the coal-air mixture, and an automatic system for preventing the explosion of the coal-air mixture is used as the source of exposure, the effect is produced by inhibiting methane-coal mixture with a fire extinguishing powder with a concentration of at least 300 g / m ³ , and as a source the impacts use an automatic methane-coal mixture explosion prevention system consisting of a methane sensor and powder fire extinguishing modules, which are located in explosive areas of the mine, while when the minimum explosive concentration of methane is reached, the methane sensor gives an electrical pulse signal to the powder emission initiator system - powder fire extinguishing modules and the fire extinguishing powder is released into the explosive zone, while the methane sensor notifies the operational bu about the emergency.

When exposed to fine fire extinguishing powder GOST 53280.4-2009, which is emitted into a coal-air mixture, an inhibition effect is achieved due to inhibition of chain oxidation reactions.

The methane-air mixture explosion is a chain reaction. Initially, due to a spark or temperature, methane reacts with oxygen to form unstable compounds that decompose with the formation of free radicals, each of which forms a new unstable compound. The rate of interaction of methane with oxygen increases sharply and an explosion occurs.

Fine particles of fire extinguishing powder can absorb a large number of free radicals, which react with each other with the formation of stable compounds. Due to the high ability of the fine particles of the extinguishing powder to absorb free radicals and stop the chain reaction of gas-phase oxidation of methane, an explosion will not occur.

It was experimentally established that inhibition by a fire extinguishing powder with a concentration of at least 300 g / m ³ prevents the methane-air mixture from exploding in mines at an early stage of its entry.

In addition, the use as an impact source of an automatic methane-coal mixture explosion prevention system consisting of a methane sensor and powder fire extinguishing modules and located in explosive areas of the mine provides instant notification of operational service and uniform achievement in the entire mine volume of a powder concentration sufficient to prevent fire and explosion, which also increases the reliability and effectiveness of preventing the explosion of methane-air mixture.

The drawing shows a process diagram of an automatic system for preventing the explosion of methane-coal mixture.

The technological scheme includes any known methane sensor 1 and any known initiators of powder discharge, for example, powder fire extinguishing modules 2. The initiator system, which operates in standby mode, is installed in explosive sections of mine 3.

The method is as follows.

As methane emerges from the coal seams into the mine, it is mixed with coal dust to form a coal-air mixture. The methane concentration varies from zero to the maximum possible values, depending on the intensity and time of the ejection, the size of the mine, ventilation conditions. Actually, in existing conditions, large volumes of gas can accumulate. When the minimum explosive concentration of methane is reached (about 5% by volume in air), methane sensor 1 generates a signal in the form of an electrical pulse to the powder initiator system, powder fire extinguishing modules 2, and the fire extinguishing powder is released into the explosive zone. At the same time, the methane sensor 1 notifies the operational service of an emergency.

The tests to prevent the explosion of methane-coal mixture on the basis of the testing center of explosives, materials and products based on them in Kemerovo showed that the concentration of extinguishing powder in the limit of 300 g / m ³ , corresponding to the largest explosion range of methane-coal mixture (8.5-9, 5%), completely excludes the possibility of spontaneous or initiated explosion or fires of this mixture within 30 minutes (see the Appendix for a copy of the Test Report of 02.09.2010).

From the tests it follows that the proposed method completely prevents the explosion of methane-air mixture in the mines, in addition, ensures the safe operation of personnel for a time sufficient to evacuate personnel and eliminate the causes of the formation of explosive mixtures.

Thus, the proposed method improves the reliability and efficiency of preventing the explosion of methane-coal mixture.

Claims (1)

A method of preventing the explosion of a coal-air mixture, including exposure to a coal-air mixture from a source at the earliest stage of its entry into the mine, the effect being produced by inhibiting a coal-air mixture, and an automatic system for preventing the explosion of a coal-air mixture is used as a source of exposure, characterized in that the effect is by inhibiting the carbon-methane mixture with a fire extinguishing powder with a concentration of at least 300 g / m ³ , and in quality The source of the impact uses an automatic methane-coal mixture explosion prevention system, consisting of a methane sensor and powder fire extinguishing modules, which are located in the explosive areas of the mine, while when the minimum explosive concentration of methane is reached, the methane sensor gives a signal in the form of an electrical pulse to the powder initiator system - modules powder fire extinguishing, and the fire extinguishing powder is released into the explosive zone, while the methane sensor notifies emergency service.