CN116255185A - A safe unsealing method for enclosed fire zones based on the viewpoint of active sites - 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

A safe unsealing method for enclosed fire zones based on the viewpoint of active sites

technical field

The invention belongs to the technical field of prevention and control of secondary spontaneous combustion of coal bodies in closed fire areas, and more specifically relates to a safe unsealing method for closed fire areas based on the viewpoint of active sites.

Background technique

At this stage, when underground coal spontaneously ignites, the method of closing the fire area is usually used to extinguish it. However, there are closed fire areas after extinguishing. At the same time, because the coal body in the closed fire area will produce high-concentration gas in a high-temperature environment, the spatio-temporal coupling between the occurrence of gas and the re-ignition fire source will easily lead to the occurrence of gas explosion accidents, and greatly increase the gas explosion during the unsealing process of the fire area. dangerous. It not only limits the utilization rate of coal mines, but also greatly increases the potential safety hazards in the mining and unsealing process. In order to enable the fire area to be unsealed safely, the "Coal Mine Safety Regulations" (hereinafter referred to as the regulations) stipulates the corresponding unsealed methods for the fire area, but the effect is still not satisfactory. Simultaneously at the present stage, people carry out the research of various ways for preventing the resurgence of the fire area, but the effect is not very satisfactory. It mainly tends to think that the re-ignition phenomenon in the closed fire area is caused by the oxygen supply of the smoldering coal body during the unsealing process, so the treatment methods are limited to increasing heat dissipation and preventing smoldering.

However, according to the in-depth research of the applicant and his team, it is found that the coal body will still re-ignite under the extinguishing condition. Furthermore, the applicant's team put forward the viewpoint of active sites, and based on the viewpoint of active sites, it is believed that the coal may have been extinguished in the closed fire area, and its re-ignition was mainly due to the thermal decomposition under high temperature conditions in the closed environment. active sites, which can exist stably under inert medium conditions. At the same time, because the generated active sites are very active, an exothermic reaction will occur rapidly once it contacts with oxygen, and the reaction of a large number of active sites will lead to a rapid increase in the temperature of the coal body, and then combustion will occur. At the same time, research has found that substances such as water or carbon dioxide can eliminate or mask these active sites, and can compete with oxygen for adsorption active sites, and are more reactive than oxygen, thus effectively inhibiting re-ignition in closed fire areas.

In view of the danger of re-ignition in unsealed and closed fire areas, it is urgent to develop a method that can effectively inhibit the secondary spontaneous combustion of coal after unsealing the closed fire area, but few people have studied the method of safe unsealed fire areas based on the active site point of view. .

Contents of the invention

The present invention aims at the technical problems existing in the prior art, and provides a relatively new safe unsealing method for closed fire zones based on the viewpoint of active sites.

In order to solve the above-mentioned technical problems, the present invention designs a method for feeding carbon dioxide, low-concentration oxygen and water mist to suppress the closed fire area, including three stages of feeding carbon dioxide, feeding low-concentration oxygen and water mist . Among them, oxygen can reduce the number of active sites in the coal body and reduce the temperature rise of the coal body under the condition of controlling the concentration and flow rate, so as to realize the suppression of the re-ignition of the coal body.

The method mainly includes the following steps:

1. Treatment before closure: When closing the fire area, it shall be closed according to the prevailing method, including pre-buried pipes or reserved holes.

2. Introduce adsorbable inert gas: Before unsealing the fire zone, inject adsorbable inert gas through pre-buried pipes or reserved holes for a certain period of time, so that the coal body can absorb adsorbable inert gas, thereby reducing the number of active sites.

3 Introducing low-concentration oxygen: before unsealing the fire area, inject low-concentration oxygen (oxygen concentration lower than 10%) through pre-buried pipes or reserved holes for a certain period of time, so that the remaining active sites in the coal body will slowly Oxidation, thereby reducing the possibility of re-ignition.

4. Passing into the masking active site material: through the pre-buried pipeline or reserved holes, the masking active site material using nitrogen gas as the carrier gas is used to mask the active site, and for the temperature increase due to the exothermic reaction in 3. The coal body is cooled. Keep it connected for a certain period of time.

5. Officially open the closed fire zone.

Preferably, carbon dioxide is selected as the adsorbable inert gas.

Preferably, water mist is used as the active site masking material.

Preferably, the water mist is formed by atomizing water or water containing substances such as surfactants, which can ensure that it can infiltrate the coal body and fill the entire closed fire area.

Preferably, the oxygen concentration of the low-concentration oxygen is about 5%, and the flow rate is adjusted as required. Due to the low-concentration oxygen stage, it is necessary to control the coal temperature to prevent it from being uncontrollable due to excessive temperature rise. Attention should be paid to controlling the flow rate of the incoming air flow and appropriately reducing the gas temperature to increase heat dissipation.

The present invention also provides another method based on the viewpoint of active sites that can effectively reduce the reburning of coal bodies in closed fire areas, which is similar to the above-mentioned method and includes the following steps:

1. Treatment before closure: When closing the fire area, close the fire area according to the prevailing method, including pre-buried pipes or reserved holes.

2. Introducing carbon dioxide gas: before unsealing the fire zone, inject carbon dioxide gas for a certain period of time through pre-buried pipes or reserved holes, so that the coal body can absorb carbon dioxide, thereby reducing the reaction between the active sites and oxygen.

3 Introducing low-concentration oxygen: before unsealing the fire area, inject low-concentration oxygen (oxygen concentration lower than 10%) through pre-buried pipes or reserved holes to slowly oxidize the remaining active sites in the coal body, thereby achieving the elimination The purpose of the active site present.

4. Introduce a mixture of water mist and carbon dioxide: before the fire zone is unsealed, inject a mixture of carbon dioxide and water mist through a pre-buried pipe or a reserved hole, fill the entire space, and keep it open for a certain period of time to reduce the explosiveness in the fire zone Gas concentration, and extinguish possible smoldering fire sources, while partially active sites can be masked by water. And the water mist uses water with a lower temperature, which can effectively reduce the temperature of the fire zone and dissolve more carbon dioxide.

5. Open the closed fire zone

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

Preferably, the mixture of carbon dioxide and water uses carbon dioxide as a carrier gas, and dissolves part of the carbon dioxide in water to better cover the active sites in the coal body and prevent the reaction; nitrogen can also be used as a carrier gas to dissolve carbon dioxide in the water, and form a water mist spray.

Preferably, the water mist temperature should be as low as possible to dissolve more carbon dioxide, facilitate the coal body to absorb carbon dioxide and neutralize the heat generated by the reaction of oxygen and active sites, and reduce the temperature of the fire zone.

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

The invention provides a relatively novel method for unsealing a closed fire area based on the viewpoint of active sites, the method is relatively simple and practical, and has a certain effect of inhibiting coal recombustion. It can be used in the unsealing process of the actual fire zone, and it can also be used in the experiment process.

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

The present invention adopts a slow reaction method between low-concentration oxygen and active sites, which contributes to the reduction of active sites in the coal body and reduces the re-ignition tendency of the coal body after unsealing, thereby reducing the risk of re-ignition of the coal body, and contributes to The safety of the fire zone is on.

The invention is beneficial for people to suppress coal spontaneous combustion or recombustion after overfire, can effectively reduce the occurrence of recombustion, and thus can reduce losses and risks caused by coal recombustion in fire areas in mines.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the accompanying drawings that need to be used in the descriptions of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings in the following description are only for the present application For some embodiments or specific implementation methods, those skilled in the art can also obtain other drawings based on these drawings without any creative effort.

Fig. 1 is the main implementation steps of the present invention;

Fig. 2 is an implementation effect diagram of the present invention, which simply shows the concrete mode when the method is implemented;

Fig. 3 is the experimental device that the present invention is used for relevant experiment in the embodiment;

Fig. 4 is the figure effect simulation of the present invention;

The symbols in the figure indicate:

1. Water inlet or air inlet; 2. Water mist or gas outlet; 3. Closed fire area; 4. Air inlet lane; 5. Return air lane; 6. Mine driving direction.

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

Detailed ways

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application, and are not intended to limit the present application.

Please refer to Figure 1 and Figure 2, the present invention designs a safe unsealing method for a closed fire zone based on the viewpoint of active sites, its main body mainly includes five steps, through which the re-ignition of the closed fire zone is performed when the closed fire zone is opened prevention. The specific implementation manner will be described in more detail by specific embodiments.

Embodiment one:

The specific preventive process method specifically includes the following steps:

(1) Pre-buried pipes or reserved holes in the fire area before sealing, and injected nitrogen to extinguish the fire.

(2) Before the fire area is unsealed, carbon dioxide gas is introduced through pre-buried pipes or reserved holes, so that the coal body can absorb carbon dioxide, thereby reducing the adsorption and reaction of oxygen. The access time is 5 hours, and the flow rate is judged according to the specific situation.

(3) Feed low-concentration oxygen (oxygen concentration is about 5%), feed the gas room for 10 hours, and flow rate is 2L/min, so that most of the reactive active sites in the coal body can undergo slow oxidation reaction, reducing their The heating rate and amplitude can be controlled to inhibit the occurrence of re-ignition.

(4) Water mist is passed through the pre-buried pipe or reserved hole for 2-3 hours. During the period, the water mist is sprayed through the pre-buried pipes and diffused in the entire closed fire area, while covering as much coal as possible. The active sites that are still present are removed using the masking effect of water.

(5) Turn on the fire zone.

Embodiment two:

Concrete process method also comprises the steps:

1) Before sealing, pre-buried pipes or reserved holes in the fire area, and injected nitrogen to extinguish the fire.

2) Before the fire zone is unsealed, carbon dioxide is injected through pre-buried pipes or reserved holes for 5 hours, so that the coal body can fully absorb carbon dioxide, thereby reducing the adsorption and reaction of oxygen.

3) Low-concentration oxygen (oxygen concentration is about 5%) is passed in for 10 hours at a flow rate of 2 L/min, so that the active sites in the coal body undergo a slow oxidation reaction, thereby reducing the possibility of re-ignition. At the same time, due to the use of low-concentration oxygen, the heating rate is reduced, reducing the occurrence of combustion.

4) Water mist is introduced through pre-buried pipes or reserved holes, wherein the water mist contains surfactants and lasts for 2-3 hours, so that the water mist is sprayed through pre-buried pipes, permeates the entire closed fire area, and covers as much as possible on coal. Use the masking effect of water to remove residual active sites.

5) Turn on the fire zone

Embodiment three:

Concrete process method comprises the steps:

① Before sealing, pre-buried pipes or reserved holes in the fire area, and injected nitrogen to extinguish the fire.

②Before unsealing the fire area, carbon dioxide gas is introduced through pre-buried pipes or reserved holes to make the coal body absorb carbon dioxide, thereby reducing the adsorption and reaction of oxygen.

③ Introduce low-concentration oxygen (the oxygen concentration is about 5%) for 10 hours, and the flow rate is 2L/min, so that the remaining active sites in the coal body will be oxidized slowly, so that the coal body in the fire zone will regenerate. The propensity to burn is reduced.

④Introduce the mixture of carbon dioxide and water mist through pre-buried pipes or reserved holes, and make it fill the entire space, reduce the concentration of explosive gases in the fire area, and extinguish some smoldering fire sources, and at the same time, some of them can be eliminated through water cover active site. And the water mist is made of lower temperature water, which can effectively reduce the temperature of the fire zone and dissolve more carbon dioxide for secondary adsorption.

⑤ Turn on the fire zone after 10 hours of water mist in ④.

Embodiment four:

The specific process can also be expressed in the following form:

1. Pre-closing treatment: Pre-buried pipes or reserved holes when closing the fire area, and injected nitrogen to extinguish the fire.

2. Introduce a mixture of carbon dioxide and water mist: Before unsealing the fire zone, inject a mixture of carbon dioxide and water mist through a pre-buried pipe or a reserved hole for 10 hours.

3. Introduce low-concentration oxygen: Introduce low-concentration oxygen (oxygen concentration is about 5%) through pre-buried pipes or reserved holes before unsealing the fire zone, and the gas inflow time is 10 hours to make the remaining active sites in the coal body Points slowly oxidize, and then achieve the purpose of elimination.

4. Introduce the mixture of water mist and carbon dioxide: Introduce the mixture of carbon dioxide and water mist through pre-buried pipes or reserved holes for 10 hours, and make it fill the entire space, reduce the concentration of explosive gases in the fire area, and extinguish some of the yin and yang. Ignition source, at the same time, some active sites can be destroyed by water masking. And the water mist is formed by using water with a lower temperature, which can effectively reduce the temperature of the fire zone and dissolve more carbon dioxide.

5. Turn on the fire zone.

Embodiment five:

This method can also be used in experimental simulations, and the equipment can be shown in Figure 4, which is mainly realized by modifying the resurgence simulation device in a closed fire area or other similar simulation devices, and is mainly used for the effect simulation of this method. Its main steps are as follows:

1. Use nitrogen a1, oxygen a2, mass flow meter b1, and reaction vessel c1 to carry out the post-combustion extinguishment experiment.

2. Inject carbon dioxide a3 for 5 hours,

3. Introduce low-concentration oxygen (oxygen concentration is 10%) for 10 hours.

4. Inject water mist for 2-3 hours, water a4 passes through atomizer b1 (ultrasonic vibration crushing or steam excitation) to form water mist, and sends it into reaction vessel c1 through carbon dioxide gas a3 and flow pump b1.

5. Finally, air is introduced.

The temperature change in this process is detected by the temperature detection device c2 and recorded.

This embodiment is only used to illustrate the application of this method in the laboratory, and other inventions can be found in the description of the equipment. The present invention only relates to the application of the method, and the device is only used to illustrate the application of the method involved in the present invention.

The flow rate parameters in the embodiments of the present invention are only used for the description of the embodiments, and do not involve specific projects, which need to be changed according to actual conditions.

The present invention provides a safe unsealing method for closed fire areas based on the viewpoint of active sites. The method is relatively simple, easy to implement, and has obvious effects; It can effectively inhibit the re-ignition caused by the reaction between the active sites in the closed fire area and oxygen, which is of great significance to the frequent re-ignition phenomenon of closed fire areas in coal mines, and effectively helps coal mines to safely unseal closed fire areas.

The principle of the present invention is to introduce carbon dioxide and water first, so that the coal body in the fire area first undergoes carbon dioxide adsorption to reduce the number of existing active sites, and the low-concentration oxygen oxidation makes the remaining active substances in the coal body contact with oxygen to react, and Reduce the temperature rise caused by the heat release of the coal body reaction, so that the temperature of the coal body will not be out of control. Then, through the masking effect of water, the residual active substances in the coal body cannot be contacted with oxygen, so that they can be eliminated in the space, and the temperature is lowered to ensure safety. According to relevant experiments, the coal body treated by the fire zone can increase the temperature by 1.28K at room temperature, and the maximum temperature can be increased by about 0.53K when 5% oxygen is introduced. The specific heating curve is shown in Figure 4. It shows that low-concentration oxygen can reduce the range of temperature rise and can be used as a means of unsealing the fire zone.

By injecting carbon dioxide, low-temperature water and low-concentration oxygen into the coal body, the invention helps to cool down the space of the coal body and reduce active sites, and can extinguish unextinguished fire sources in time. If there is a heat source and an explosion occurs, it can also effectively reduce casualties, and at the same time, the internal fire can be extinguished through water mist.

In the description of the present invention, it should be understood that the term "nitrogen fire extinguishing" can be replaced by all existing fire extinguishing methods, and the description of the present invention is only for convenience of understanding, and is not intended as a limitation of the present application.

In describing the present invention, it is to be understood that terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical" , "horizontal", "top", "bottom", "inner", "outer" and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the application and simplifying the description. It is not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed, or operate in a particular orientation, and thus should not be construed as limiting the application.

In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, a feature defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present application, "plurality" means two or more, unless otherwise specifically defined.

The above descriptions are only preferred embodiments of the application, and are not intended to limit the application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the application should be included in the protection of the application. within range.

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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