RU2513790C1 - Method to prevent ignition of methane and air mixture - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: method to prevent ignition of a methane and air mix includes pneumatic hydraulic irrigation of a coal breaking area, automatic control of methane content by sensors and introduction of an inhibiting gas into a mine atmosphere. Besides, the inhibiting gas is introduced under pressure automatically via a system of pneumatic hydraulic irrigation with achievement of methane concentration in air from 1.9 to 2%, with concentration of inhibiting gas from 0.1 to 2% of the protected volume and the specified content of oxygen in the mine atmosphere. As the methane level drops below 1%, supply of inhibiting gas is automatically stopped.

EFFECT: neutralisation of produced methane and air mixes of explosive concentrations and prevention of their ignition.

2 cl

Description

The invention relates to mining, and in particular to the field of preventing ignition and explosion of methane-air mixtures, and can be used in the development of coal deposits by underground mining.

There is a method of inertization to prevent fires or explosions by reducing the oxygen content in the protected zone to a basic level of inertization compared to ambient air. In this case, the oxygen content is compared with its threshold value, and then if the oxygen content falls below the threshold value, fresh air is supplied (RF patent No. 2372954, class A62C 2/00, A62C 39/00, filed November 3, 2005, published November 20, 2009). A significant drawback of the known technical solution is that at a certain moment a decrease in the level of oxygen in the mine atmosphere may occur.

There is a known process of inertization of the atmosphere of a coal mine during operation of the combine in the face, including the introduction of inert gases, for example nitrogen, into the stream of produced coal onto a cutting tool of a mining machine (US patent No. 5273344, class 299/12, filed December 21, 1992, published December 28, 1992 .1993). The aim of the known method is to prevent ignition of the methane-air mixture by supplying an inert gas to the place of operation of the cutting tool of the combine, and due to injection of a large amount of gas into this area, the oxygen concentration decreases. A disadvantage of the known invention is that a continuous gas supply is made to inertize the protected zone. This leads to an increase in production costs.

As a prototype, a well-known method of eliminating a fire in enclosed spaces, a system for its implementation and a pneumatic-acoustic spraying device (RF patent No. 2130328, class A62C 3/00, A62C 35/00, claimed on 08/03/1999, published on 05/20/1999, was adopted. ) In the proposed method for eliminating fire in enclosed spaces, a mixture of inert gas and water is supplied by a pneumoacoustic method to the combustion zone. The ratio of gas to water is 0.7-1.5 parts by weight. The method involves the use of a significant amount of inert gas, which can be effective at the combustion stage, and not at the stage of preventing fire.

All currently known methods of ensuring fire safety in mining operations (flame arresters, spark arresters, strong dilution with inert gases, etc.) are not always effective. As practice has shown, known methods of using inert gases require the use of large amounts of diluent gases, which is not always effective and convenient to prevent the ignition process. In addition, there may be problems with the safety of people in the protected area.

The basis of the invention is the task of improving preventive measures to prevent the risk of ignition and explosion of methane-air mixture.

The technical result of the claimed invention is the neutralization of the resulting methane-air mixtures of explosive concentrations and the prevention of their ignition.

To solve this problem, a method for preventing the ignition of a methane-air mixture is proposed, including pneumohydro-irrigation of the coal destruction zone, automatic monitoring of the methane content by sensors and the introduction of an inhibiting gas into the mine atmosphere.

The difference is that the inhibitory gas is injected automatically under pressure through a pneumohydrothermal irrigation system when the methane concentration in the air reaches 1.9 to 2%, with the inhibitory gas concentration from 0.1% to 2% of the protected volume and the specified oxygen content in the mine atmosphere .

Another difference is that when the methane level drops below 1%, the supply of inhibitory gas automatically stops.

As an inhibiting gas, for example, complex compositions based on fluorinated hydrocarbons that react chemically with methane can be used, leading to the formation of low-activity products and termination of the reaction chains of the combustion process at the initial stage of their occurrence, which greatly complicates and prevents the ignition of methane . Chemical methods of inhibition are described in the articles: “On the Promotion and Inhibition of Methane Combustion by Fluorinated Hydrocarbons in Oxidizing Media with Different Oxygen Content” V.V. Azatyan, Yu.N. Shebeko, A.Yu. Shebeko, V.Yu. Navtsenya, w- l “Chemical Physics”, 2010, No. 9, pp. 42-51, and “Chemical Methods of Inhibition of Explosive Atmospheres” V.V. Azatyan, T.R.Timerbulatov, A.A. Trubitsyn, N.V. Trubitsyna , Yu.M. Filatov, S. V. Shatirov., Bulletin of the SC VostNII, 2012, No. 2, p. 38-46.

Mining operations are characterized by the danger of ignition of methane and coal dust. At the same time, the intensification of coal mining processes significantly increases the risk of fire and explosion of methane-air mixture. Currently, the use of known protective measures does not allow to completely neutralize and prevent the ignition of methane in mine workings at different stages of work. Therefore, the issue of preventing explosions of gas-dust mixtures and ensuring the safety of working people remains relevant.

The proposed method for preventing ignition of a methane-air mixture involves the use of an inhibiting gas under certain conditions to timely neutralize gas-dust mixtures and prevent their formation in the future.

Irrigation is carried out with a finely dispersed water-air mixture under pressure from the coal destruction zone. The pressure head of the water-air flow can vary depending on the volume and type of mining. A fine-dispersed water-air curtain will neutralize the ignition source. Thus, the process of dust suppression is carried out in a hazardous area on fire.

At the same time, for the timely automatic injection of inhibitory gas into mine workings, in the places of the most probable breakthrough and accumulation of methane, sensors are monitored, for example, MGM-1 (TU 4215-015-05798310-2004), the methane content in the mine atmosphere near operating equipment and locations of alleged methane accumulation. When the methane concentration in the air reaches from 1.9 to 2%, an additional inhibitory gas with a concentration of 0.1% to 2% of the protected volume is automatically injected through the pneumohydro irrigation system under pressure. The inhibitory gas is introduced ahead of the time until the formation of an explosive concentration of methane-air mixture, while neutralizing methane in the atmosphere of the mine. An atmosphere that is inactive for the combustion process is created directly in the place of mining, the process of formation of a methane-air environment hazardous for ignition is interrupted.

Considering that the supply of inhibitory gas is carried out periodically and its concentration varies insignificantly, the oxygen-air balance necessary for human life is not disturbed.

When the methane concentration is reduced to below 1%, the supply of inhibitory gas is turned off, which prevents its excessive and unnecessary consumption.

A significant advantage of the proposed method for preventing the ignition of a methane-air mixture is its efficiency, as well as ensuring the safety of personnel throughout the entire period of work in underground conditions and maintaining the oxygen level in this case within normal limits.

Claims (2)

1. A method of preventing ignition of a methane-air mixture, including pneumohydrothermal irrigation of the coal destruction zone, automatic monitoring of methane content by sensors and introducing an inhibitory gas into the mine atmosphere, characterized in that the inhibitory gas is injected under pressure automatically through a pneumatic irrigation system when the methane concentration in the air reaches 1.9 up to 2%, with an inhibitory gas concentration of 0.1 to 2% of the protected volume and a given oxygen content in the mine atmosphere. 2. The method according to claim 1. characterized in that when the methane level drops below 1%, the flow of inhibitory gas automatically stops.