CN116255185A - Safe unsealing method for sealed fire area based on active site view - Google Patents

Abstract

The invention discloses a safe unsealing method for a sealed fire area based on an active site point of view, which has the characteristics of simplicity, easiness, high feasibility, obvious effect and the like. The method mainly comprises the steps of (1) embedding pipelines or reserving holes when a fire area is closed; (2) Carbon dioxide gas is introduced through a pre-buried pipeline or a reserved hole, and the specific flow speed and time of the carbon dioxide gas are determined according to specific conditions, so that the carbon dioxide gas is filled in a fire area for a certain time; (3) Introducing low-concentration oxygen through the pre-buried pipeline or the reserved hole, detecting the temperature and the gas concentration change, and keeping the temperature and the gas concentration change for a certain time; (4) Spraying water mist for a certain time through a pre-buried pipeline or a reserved hole, so as to ensure that the water mist fills the whole closed fire area; (5) After the treatment is completed, the fire area is opened, underground air is introduced, and the fire area is safely opened. The method can enable the closed fire area to be safely opened.

Description

Safe unsealing method for sealed fire area based on active site view

Technical Field

The invention belongs to the technical field of secondary spontaneous combustion prevention and control of coal opened in a closed fire zone, and particularly relates to a safe unsealing method for the closed fire zone based on an active site viewpoint.

Background

At present, when underground coal is spontaneously burned, a method of closing a fire area is usually adopted for extinguishing, but the closed fire area after extinguishing exists, and when the closed fire area is opened again, the phenomenon of coal re-burning is very easy to occur. Meanwhile, high-concentration gas can be generated by the coal in the closed fire area in a high-temperature environment, so that gas explosion accidents are easily caused by space-time coupling of gas and the occurrence of a reburning fire source, and the danger in the unsealing process of the fire area is greatly increased. Not only limiting the utilization rate of the coal mine, but also greatly increasing the potential safety hazard in the exploitation and unsealing process. In order to ensure that the fire area can be safely unsealed, the coal mine safety regulations (hereinafter referred to as regulations) prescribe a corresponding fire area unsealing mode, but the effect is still not satisfactory. At the same time, at the present stage, people research various modes for preventing the re-burning of the fire area, but the effect is not ideal. It is mainly intended that the re-ignition phenomenon in the closed fire area is caused by oxygen supply during unsealing of the yin-fire coal, so that the treatment mode is limited to increase of heat dissipation and prevention of smoldering.

According to the intensive studies of the applicant and the team thereof, the phenomenon of afterburning of the coal body under the extinguishing condition is found. Further, the applicant group has proposed an active site perspective and, depending on the active site perspective, it is believed that coal bodies may have extinguished in a confined fire zone, which reburning occurs mainly due to the thermal decomposition under high temperature conditions in a confined environment to produce a large number of active sites which are capable of stable existence under inert medium conditions. Meanwhile, the generated active sites are very active, so that exothermic reaction can be rapidly generated once the active sites are contacted with oxygen, and a large amount of active site reactions can lead to rapid increase of the temperature of coal body, so that combustion can occur. Meanwhile, the research shows that substances such as water or carbon dioxide can eliminate or mask the active sites, can compete with oxygen to adsorb the active sites, and has higher reactivity than oxygen, so that the afterburning of a closed fire zone can be effectively inhibited.

In view of the risk of re-ignition in the unsealed sealed fire area, there is a need in the present stage to develop a method capable of effectively inhibiting secondary spontaneous combustion of coal after unsealing the sealed fire area, and a method for researching the safe unsealing fire area based on the viewpoint of active sites.

Disclosure of Invention

Aiming at the technical problems existing in the prior art, the invention provides a novel safe unsealing method for a sealed fire area based on the viewpoint of active sites.

In order to solve the technical problems, the invention designs a method for introducing carbon dioxide, low-concentration oxygen and water mist to inhibit a closed fire zone, which comprises three stages of introducing carbon dioxide, introducing low-concentration oxygen and introducing water mist. Wherein the oxygen can reduce the number of active sites of the coal body and reduce the temperature rise of the coal body under the condition of controlling the concentration and the flow rate, thereby realizing the inhibition of the afterburning of the coal body.

The method mainly comprises the following steps:

1. and (3) sealing pretreatment: the fire zone is sealed according to a passing method, and the fire zone is sealed and contains pre-buried pipelines or reserved holes.

2. Introducing adsorbable inert gas: before unsealing, the adsorbable inert gas is introduced into the fire area through the pre-buried pipeline or the reserved hole for a certain time, so that the coal body adsorbs the adsorbable inert gas, and the number of active sites is reduced.

3, introducing low-concentration oxygen: before unsealing, low-concentration oxygen (the oxygen concentration is lower than 10%) is introduced through the pre-buried pipeline or the reserved hole, and the low-concentration oxygen is introduced for a certain time, so that the residual active sites in the coal body are slowly oxidized, and the possibility of reburning is further reduced.

4. And (3) introducing a masking active site substance: and (3) introducing active site masking substances which take nitrogen as carrier gas through the pre-buried pipeline or the reserved hole, masking active sites, and cooling the coal body which is heated due to reaction heat in step (3). And keeping the air in for a certain time.

5. And formally opening the closed fire area.

Preferably, the adsorbable inert gas is carbon dioxide.

Preferably, the active site masking material is a water mist.

Preferably, the water mist is formed by atomizing water or water containing a substance such as a surfactant, which ensures that the coal body is wetted and the whole closed fire area is filled.

Preferably, the oxygen concentration of the low concentration oxygen is about 5%, and the flow rate is adjusted as required. Because the low-concentration oxygen is introduced into the coal-gas heat dissipation device, the temperature of the coal needs to be controlled, uncontrollable caused by excessively high temperature rise of the coal is prevented, the flow of the introduced air flow needs to be controlled, and the temperature of the gas is reduced appropriately so as to increase heat dissipation.

The invention also provides another method for effectively reducing the afterburning of coal in a closed fire zone based on the viewpoint of active sites, which is similar to the method, and comprises the following steps of:

1. and (3) sealing pretreatment: the fire zone is sealed according to a passing method and comprises pre-buried pipelines or reserved holes.

2. Introducing carbon dioxide gas: before unsealing, carbon dioxide gas is introduced into the fire area through the pre-buried pipeline or the reserved hole for a certain time, so that the coal body adsorbs carbon dioxide, and the reaction between the active site and oxygen is reduced.

3, introducing low-concentration oxygen: and low-concentration oxygen (the oxygen concentration is lower than 10%) is introduced into the fire zone through the pre-buried pipeline or the reserved hole before unsealing, so that the residual active sites in the coal body are slowly oxidized, and the aim of eliminating the existing active sites is fulfilled.

4. Introducing a water mist and carbon dioxide mixture: before unsealing, the mixture of carbon dioxide and water mist is introduced through the pre-buried pipeline or the reserved hole, the whole space is filled with the mixture, the mixture is kept to be introduced for a certain time, the concentration of explosive gas in the fire area is reduced, a smoldering fire source possibly existing is extinguished, and part of active sites can be shielded through water. And the water mist adopts water with lower temperature, so that the temperature of a fire area can be effectively reduced, and more carbon dioxide is dissolved.

5. Opening and closing fire zones

Preferably, the carbon dioxide introduced for the first time can also be introduced in the form of a mixture of water mist and carbon dioxide.

Preferably, the mixture of carbon dioxide and water adopts carbon dioxide as carrier gas, and part of carbon dioxide is dissolved in water, so that active sites in the coal body are better masked, and the reaction is prevented; nitrogen may also be used as carrier gas to dissolve carbon dioxide in water and form a spray.

Preferably, the water mist temperature should be as low as possible to dissolve more carbon dioxide, facilitating the adsorption of carbon dioxide by the coal body and the neutralization of heat generated by the reaction of oxygen with the active sites, reducing the fire zone temperature.

Compared with the prior art, the invention has the following beneficial effects:

the invention provides a novel method for unsealing a sealed fire area based on the viewpoint of active sites, which is simple and practical and has a certain effect of inhibiting the afterburning of coal. The method can be used in the actual fire area unsealing process and also can be used in the experimental process.

The invention utilizes the adsorption effect of the coal body on carbon dioxide and the masking effect of water on active sites in the coal body to inhibit the reaction of the active sites and oxygen.

The invention adopts a slow reaction method of low-concentration oxygen and active sites, which is beneficial to reducing the active sites in the coal body and reducing the coal body reburning tendency after unsealing, thereby reducing the coal body reburning risk and being beneficial to safely opening a fire zone.

The invention is beneficial to people to inhibit the phenomenon of re-combustion after spontaneous combustion or excessive fire of coal, and can effectively reduce the occurrence of re-combustion, thereby reducing the loss and danger caused by the re-combustion of coal bodies in fire areas in mines.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required for the embodiments or the description of the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments or specific implementations of the present application, and that other drawings may be obtained according to these drawings without inventive effort to a person skilled in the art.

FIG. 1 is a diagram of the main implementation steps of the present invention;

FIG. 2 is a diagram showing the implementation effect of the invention, and simply shows the specific mode of implementation of the method;

FIG. 3 is an experimental set-up of the invention for use in the relevant experiments in the examples;

FIG. 4 is a graph effect simulation of the present invention;

wherein the symbols in the drawings indicate:

1. water inlet or air inlet; 2. a water mist or gas outlet; 3. closing the fire area; 4. an air inlet lane; 5. a return airway; 6, tunneling direction of the mine.

a1 is nitrogen, a2 is oxygen, a3 is carbon dioxide, a4 is water, b1 is a flow pump and an atomizer, b2 is a mass flowmeter, c1 is a reaction vessel, and c2 is a temperature measuring device.

Detailed Description

In order to make the technical problems, technical schemes and beneficial effects to be solved by the present application more clear, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.

Referring to fig. 1 and 2, the present invention provides a method for safely unsealing a sealed fire area based on an active site perspective, wherein the main body of the method mainly comprises five steps, and the five steps are used for preventing the re-ignition when the sealed fire area is opened. Wherein the embodiments are more particularly described by way of example only.

Embodiment one:

the specific preventive process method specifically comprises the following steps:

(1) Before closing, pipelines or reserved holes are pre-buried in the fire area, and nitrogen is introduced to extinguish the fire.

(2) Before unsealing, carbon dioxide gas is introduced through the pre-buried pipeline or the reserved hole, so that the coal body adsorbs carbon dioxide, and further the adsorption and reaction of oxygen are reduced. The charging time is 5h, and the flow rate is judged according to specific conditions.

(3) Low-concentration oxygen (the oxygen concentration is about 5%) is introduced, the gas is introduced for 10 hours, the flow speed is 2L/min, most active sites capable of reacting in the coal body are subjected to slow oxidation reaction, the temperature rising rate and the temperature range are reduced, and further the occurrence of reburning is inhibited.

(4) And introducing water mist through the pre-buried pipeline or the reserved hole for 2-3 hours. During the period, the water mist is sprayed and diffused in the whole closed fire area through the pre-buried pipeline, and simultaneously, the water mist is covered on the coal body as much as possible. The masking effect of water is used to remove active sites that are still present.

(5) And opening the fire area.

Embodiment two:

the specific process method also comprises the following steps:

1) Before closing, pipelines or reserved holes are pre-buried in the fire area, and nitrogen is introduced to extinguish the fire.

2) Before unsealing, carbon dioxide is introduced through the pre-buried pipeline or the reserved hole, and the gas is introduced for 5 hours, so that the coal fully adsorbs the carbon dioxide, and further the adsorption and reaction of oxygen are reduced.

3) Low-concentration oxygen (the oxygen concentration is about 5%) is introduced, the gas introduction time is 10 hours, and the flow speed is 2L/min, so that the active sites in the coal body are subjected to slow oxidation reaction, and the possibility of reburning is further reduced. Meanwhile, as low-concentration oxygen is adopted, the temperature rising rate is reduced, and the combustion condition is reduced.

4) Introducing water mist through the pre-buried pipeline or the reserved holes, wherein the water mist contains the surfactant for 2-3 hours, so that the water mist is sprayed through the pre-buried pipeline, is diffused in the whole closed fire area, and covers the coal body as much as possible. Residual active sites are removed by the masking effect of water.

5) Starting fire zone

Embodiment III:

the specific process method comprises the following steps:

(1) before closing, pipelines or reserved holes are pre-buried in the fire area, and nitrogen is introduced to extinguish the fire.

(2) Before unsealing, carbon dioxide gas is introduced through the pre-buried pipeline or the reserved hole, so that the coal body adsorbs carbon dioxide, and further the adsorption and reaction of oxygen are reduced.

(3) Low-concentration oxygen (the oxygen concentration is about 5%) is introduced, the gas is introduced for 10 hours, the flow speed is 2L/min, and the active sites remained in the coal body are slowly oxidized, so that the reburning tendency of the coal body in a fire area is reduced.

(4) The mixture of carbon dioxide and water mist is introduced through the pre-buried pipeline or the reserved hole, and the mixture is filled in the whole space, so that the concentration of explosive gas in a fire area is reduced, part of smoldering fire sources are extinguished, and part of active sites can be simultaneously extinguished through water masking. And the water mist is made of water with lower temperature, so that the temperature of a fire area can be effectively reduced, and more carbon dioxide is dissolved for secondary adsorption.

(5) And (3) opening a fire area after the water mist in the step (4) is introduced for 10 hours.

Embodiment four:

the specific process can also be expressed as follows:

1. and (3) sealing pretreatment: and (5) pre-burying a pipeline or reserving holes in the fire area, and introducing nitrogen to extinguish the fire.

2. Introducing a mixture of carbon dioxide and water mist: before unsealing, introducing a mixture of carbon dioxide and water mist through a pre-buried pipeline or a reserved hole for 10 hours.

3. Introducing low-concentration oxygen: before unsealing, low-concentration oxygen (the oxygen concentration is about 5%) is introduced through the pre-buried pipeline or the reserved hole, and the gas is introduced for 10 hours, so that the residual active sites in the coal body are slowly oxidized, and the aim of destroying is achieved.

4. Introducing a water mist and carbon dioxide mixture: the mixture of carbon dioxide and water mist is introduced through the pre-buried pipeline or the reserved hole for 10 hours, and the mixture is filled in the whole space, so that the concentration of explosive gas in a fire area is reduced, part of smoldering fire sources are extinguished, and part of active sites can be extinguished through the masking of water. And the water mist is formed by adopting water with lower temperature, so that the temperature of a fire area can be effectively reduced, and more carbon dioxide is dissolved.

5. And opening the fire area.

Fifth embodiment:

the method can also be used in experimental simulation, the equipment can be shown in fig. 4, the method is mainly realized by modifying a closed fire area reburning simulation device or other similar simulation devices, and the method is mainly used for simulating the effect of the method. The method mainly comprises the following steps:

1. the post-combustion extinguishing experiment was first performed using nitrogen a1, oxygen a2 and mass flow meter b1, and reaction vessel c 1.

2. Introducing carbon dioxide a3 for 5h,

3. low concentration oxygen (10% oxygen concentration) was introduced for 10h.

4. Introducing water mist for 2-3h, forming water mist by the water a4 through the atomizer b1 (ultrasonic vibration crushing or steam excitation), and sending the water mist into the reaction vessel c1 through the carbon dioxide gas a3 and the flow pump b 1.

5. And finally, introducing air.

The process temperature change is detected by the temperature detecting means c2 and recorded.

This example is only for the purpose of illustrating the application of the method in a laboratory, and the description of the apparatus presents other inventions. The invention relates only to the application of the method of use and the apparatus device is only intended to represent the application of the method referred to in the description of the invention.

The flow rate parameters in the embodiments of the present invention are used as examples only, and do not relate to specific engineering, and specifically need to be changed according to actual situations.

The invention provides the safe unsealing method for the sealed fire area based on the viewpoint of the active site, which is simpler, easy to implement and obvious in effect; for coal yards with high spontaneous combustion tendency and more closed fire areas such as Xinjiang, inner Mongolia and the like, the reburning caused by the reaction of active sites in the closed fire areas and oxygen can be effectively inhibited, the method has great significance on the phenomenon of reburning of the closed fire areas frequently seen by the existing coal mine, and the method is effective in helping the coal mine to safely unseal the closed fire areas.

The principle of the invention is that carbon dioxide and water are introduced first to make the coal body in the fire area firstly adsorb carbon dioxide, reduce the number of active sites stored, make the residual active substances in the coal body react with oxygen through low-concentration oxygen oxidation, and reduce the temperature rise amplitude caused by the exothermic reaction of the coal body, so that the coal body cannot be out of control. Then, residual active substances in the coal body cannot be contacted with oxygen through the masking effect of water, so that the active substances are eliminated in space, the temperature is reduced, and the safety is ensured. According to the related experiments, the maximum temperature of the air is increased by 1.28K at normal temperature, and the maximum temperature of the 5% oxygen is increased by about 0.53K. The specific temperature rise curve is shown in fig. 4. The low-concentration oxygen can reduce the temperature rise range and can be used as a means for unsealing a fire area.

The invention is beneficial to the temperature reduction and active site reduction of the coal body space by injecting carbon dioxide, low-temperature water and low-concentration oxygen into the coal body, and can extinguish the non-extinguished fire source in time. If a heat source exists, explosion occurs, the casualties can be effectively reduced, and meanwhile, the extinguishing work of internal fire can be completed through water mist.

In the description of the present invention, it is to be understood that the term "nitrogen fire suppression" may be used interchangeably with all existing methods for suppressing fires, and that the description of the present invention is for ease of understanding only and is not to be taken as a limitation of the present application.

In the description of the present invention, it should be understood that the directions or positional relationships such as the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of description and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

The foregoing description of the preferred embodiments of the present application is not intended to be limiting, but is intended to cover any and all modifications, equivalents, and alternatives falling within the spirit and principles of the present application.

Claims (9)

1. The safe unsealing method for the sealed fire area based on the viewpoint of the active site utilizes the auxiliary fire area such as carbon dioxide, low-concentration oxygen, water mist and the like to unseal based on the viewpoint of the active site, and is characterized by comprising the following steps: (1) closing the fire zone; (2) introducing an adsorptive inert gas. (3) introducing low-concentration oxygen: (4) introducing an active site inhibiting substance; (5) opening the fire zone.

2. The method for safely unsealing a fire area sealed off based on the viewpoint of an active site according to claim 1, wherein oxygen with low concentration is introduced at a certain flow rate.

3. The low-concentration oxygen gas introduced according to claim 2, which can be formed by mixing oxygen with other gases.

4. According to claim 1, it is possible to use other existing methods simultaneously in different steps.

5. The method according to claim 1, wherein the inert gas is carbon dioxide or nitrogen and inert gas mixture containing the relevant gas.

6. The method of claim 1 wherein the masked active site material is a water mist.

7. According to claim 3, the oxygen concentration in the low concentration oxygen is lower than 10%.

8. The water mist of claim 6, wherein the water mist is capable of containing a plurality of other substances such as carbon dioxide gas and a surfactant.

9. A water mist for feeding in according to claim 8, characterized in that water of a lower temperature is used.

According to claim 4, the water mist can be fed into the closed fire zone by means of carbon dioxide or nitrogen as carrier gas.

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