SU1749476A1 - Method for fighting of spontaneous fires in coal mine goafs - Google Patents

Abstract

SUMMARY OF THE INVENTION: A gas well is introduced into the mined space of the well and supplied through it with a gas-mechanical foam. The intensity of the foam supply is determined from a mathematical expression. To do this, the oxygen concentration in the incoming air jets and outgoing from the fire site and the temperature of the fire site and surrounding rocks is measured. 1 il.

Description

The invention relates to the mining industry and can be used to extinguish endogenous fires in collapsed rock massifs.

There is a method of preventing endogenous fires in mines, which consists in the fact that during the treatment of the collapsed rock mass air-mechanical foam determines the volume of the treated area, the initial humidity and density of the collapsed rock mass, as well as the multiplicity of the foam and the density of its liquid phase. the amount of foam is determined from the mathematical expression. This method can be effectively used to prevent coal self-heating, if the contours of the fire-hazardous zone are known, i.e. places of accumulation of coal in the collapsed array. In this case, setting the volume of the treated zone, determine the amount of foam that needs to be fed into this zone in order to phlegmatize the process of oxidation and self-heating of the coal.

However, to extinguish endogenous fires, this method is not applicable due to the following circumstances. In order to effectively suppress the spontaneous combustion of coal by any refrigerant (for example, air-mechanical foam), it is necessary to know the amount of foam not only to prevent oxidation and self-heating of coal, but also to suppress the source of fire and cool the surrounding rocks to the natural temperature of the rocks of the horizon. The essence is that when extinguishing (localizing) an endogenous fire with foam, intensive evaporation of moisture and its removal outside the treated area occurs. Therefore, in order to effectively suppress the source of fire, continuous supply of foam is necessary in an amount many times greater than the volume of the treated area.

Closest to the present invention is a method for the prevention and localization of endogenous fires, including the drilling of a well into a developed air gap.

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space and supply of gas-mechanical foam for treatment of a collapsed array with a given intensity, which determines the duration of filling the treated area with foam, based on the resistance of the foam to destruction and the performance of the foam generator, in this case, determines the duration of processing the fire-hazardous zone until it is completely filled with foam taking into account the rheology of the foam - multiplicity and durability.

The disadvantage of this method is that it does not take into account the dynamics of heat-generation by the site of fire and heat removal by the collapsed rocks enclosing the hearth. Therefore, there is no objective criterion for estimating the amount of foam required for suppressing fire and cooling the surrounding rocks. In some cases, this leads to an unjustifiably large consumption of frother contaminating reservoirs into which mine water is discharged, in others to poor quality treatment of the collapsed massif and as a result, to the occurrence of recurrence of spontaneous combustion.

The aim of the invention is to increase the efficiency of extinguishing endogenous fires in collapsed arrays due to the intensification of heat removal.

The goal is achieved in that according to the method of preventing and localizing endogenous fires, including drilling wells into the developed space and supplying gas-mechanical foam for treating the collapsed massif with a given intensity, determine the oxygen concentration in the source and end air from the fire source and the temperature of the fire source and its surrounding rocks, and the gas-mechanical foam is supplied with an intensity determined from leduyuschego mathematical expression:

and

28 10 with toj-oi

mli (h4-4l

ln I C ° l -Yes-Cho) Tyu + pgt |. . - (0, -g-a,) Tf + 5

(one)

where I - the intensity of the foam, m / h;

m - reservoir thickness, m;

It is the strike distance between the points of entry of wells into the open space, in which the temperature is higher than the natural temperature of the rocks of this horizon by 5 ° C, m;

12 is the distance between the points of entry of wells into the open space, in which the temperature is 5 ° C above the natural horizon, m;

40 - coefficient characterizing the average distance of foam advancement in the collapsed rocks from the well, m;

1.5 - coefficient characterizing the average time of foam movement from the drilled wells, h;

4 U (Co - Sysh)

"one

(In Co -In Sish) (0.06 + W)

10 coefficient taking into account the generation of heat by the fire,

.

1b7

m (W + 0, C6)

- coefficient,

15

20

thirty

35

taking into account the removal of heat from the fire center by the collapsed rocks of the treated area,

Oz - coefficient taking into account the removal of heat from the fire center foam. take, depending on the multiplicity (K) of the resulting foam K: 20 40 6080100120140 as 104: 2,52,1 1,71,, 41,10,80,6

4 - coefficient characterizing the ratio of the mass of coal in the heated zone to its volume, kg / m3,

1.25 - coefficient characterizing the rate of heat transfer by air leaks in the collapsed rocks, m / s;

Toch - the temperature of the fire, ° C

That is the temperature of the rocks surrounding the fire, ° C;

Tg is a natural rate, the composition of rocks at a given depth, ° C;

U is the average specific sorption rate of oxygen by coal, MJ / (C kg);

Co is the concentration of oxygen in the stream of air entering the fire, the volume fraction;

4P Сисх - oxygen concentration in the stream of air emanating from the fire, volume fraction;

W-humidity of coal in the emergency area, the proportion of volume.

-c Determining the concentration of oxygen in the air stream coming to the hearth and outgoing from the fire center allows to calculate the coefficient a, which takes into account the generation of heat by the fire center. From the CQ oxygen content in the incoming and outgoing jets, it is possible to quantify the state of the fire source. On the one hand, determining the temperature of the fire source provides a qualitative characteristic of the spontaneous combustion center, and on the other hand, it is possible to establish a quantitative relationship between the degree of development of the fire site and the intensity of foam supply to the developed space for its elimination.

The temperature of the surrounding rocks is determined in order to estimate the locations and the area of distribution of the endogenous fire in order to correctly determine the size of the developed space, which must be treated with foam in order to cool the crushed rocks to a temperature that is natural for a given depth of development. This will make it possible not only to eliminate the source of fire, 10 but also to prevent spontaneous combustion of other accumulations of coal in the fire-hazardous zone.

Thus, the determination of these parameters, which objectively characterize the state of an endogenous fire, allows one to scientifically determine the optimal foam supply rate. In addition, it also makes it possible to promptly resolve the issue of determining the necessary amount of a frother and other material and labor costs associated with extinguishing a fire.

The drawing schematically shows the implementation of the method, 25

The drawing shows foam generators 1, fire hose 2, the open space of lava 3, three-way grounding 4, wells 5, field ventilation drift 6, field haulage drift 30 7, lava 8, ventilation (formation) drift 9, skag 10 and the conveyor drift 11.

The method is implemented as follows.

In the area of the alleged fire source 35 of the developed space 3 of the borehole bore, using the well temperature control device (UKTS), the temperature at the exit of each well into the developed space is measured. The wells will be 40 pt until at least four wells are drilled, delineating the fire (two in the fall and two in strike), in which the temperature exceeds the natural temperature of the rocks 45 of this horizon by 5 ° С. When the temperature in the coal accumulation of the developed- secret space of 45-60 ° C (depending on the humidity of the coal) reaches, the moisture of the shallow pores of the mesopores begins to form in the coal coal, and the air oxygen is adsorbed on their surface. oxidation and self-heating coal. |

In order to determine the concentration of oxygen in the incoming air and the outgoing air stream, samples are taken in the workings that delineate the developed space and subjected to laboratory analysis. The temperature of the rocks surrounding the seat of fire (To) is defined as the average measured in those wells (at the entrance of the wells to the developed space) in which the temperature is higher than

than (TH-5) ° C, i.e. That is - L + T2 + - + TEC

I p provided that Ti, T2tp Tr + 5.

In order to determine the temperature of the fire source, the streams coming to the hearth and outgoing from the fire source take samples of gases for ethylene and acetylene content. Then, according to the VNIIGD method, the temperature of the source of fire is calculated according to the ratio of ethylene and acetylene (Set / Sats) outgoing from the fire center. The natural temperature of the rocks at a given depth of development (Tg) is determined by the mine’s instrumental geologist for each horizon. The average value of the specific rate of oxygen sorption by coal (0) takes according to the data of the All-Russia Research Institute of Railway Transport. The moisture of the coal (W) is determined by sampling the coal in the emergency area. On the basis of the parameters obtained, the foam (I) supply rate is determined from expression (1). Then, the parameter I selects the number of foam generators with which the foam can be supplied (m3 / h) into the open space, not less than I. i -. g.,.

Foam launch into the open space is carried out in four, at a minimum, wells drilled around the intended fire source, the inlet temperature of which is higher than the natural temperature of the rocks of this horizon. After the launch of the foam, samples are taken every hour., For the content 02, CO, H2, CU2. and CJ4 outgoing air from the fire source. Sampling was done until then. until the CO content is reduced to a volume fraction of 0.00170%, and CO2 to 1%. A decrease in CO and C02 to maximum permissible concentrations indicates the absence of burning. However, to prevent the possibility of recurrence of spontaneous combustion, it is necessary to reduce the temperature of the rocks surrounding the seat of fire to a temperature that is natural for the rocks of this horizon. Therefore, while continuing to inject foam into the developed space, the temperature at the entrance to the developed space of those wells in which the temperature before the start of the foam was greater than the value of Tg + 5 is measured.

If the temperature at least in one of these wells exceeds the natural for the rocks of this horizon, the flow

Foams do not stop and after 1 h they re-measure the temperature in these wells. Such a periodicity of temperature measurement is maintained until the temperature in said wells decreases to a value of Tr. After that, the supply of foam to the generated space is stopped and after 6 hours (when the foam in the developed space is destroyed), a control temperature measurement in all wells is carried out in order to identify the possibility of spontaneous ignition recurrence.

The method is carried out as follows.

The collapsed massif of the worked-out space is processed during excavation of formation 4 through field drifts. To establish the propagation contours of the endogenous fire from the field ventilation drift 6 into the excavated space 3, nine wells were drilled 5, at the entrance to which the temperature was measured using the temperature sensor of the well temperature control device (UKTS). The temperature in the well I is 36 ° C; And - 40 ° C; III - 110 ° C; IV - 40 ° C; V - 40 ° C; VI — 116 ° C; VII - 134 ° C; VIII - 40 ° C; IX - 35 ° C. At the same time, the temperature is determined by the ratio of C3t / Sats. is 310 ° C. This suggests that the wells did not hit the epicenter of the fire source, therefore, the calculation of the fire temperature T0ch 310 ° C is taken into account. The oxygen content, as determined by laboratory analysis of samples, in the air stream entering the hearth is Co-0.20 parts of the volume, and 0.08 shares of the volume in the outgoing air source from the source Sysh. The temperature of the rocks surrounding the fire site is determined as the average for wells II), VI and IV:

 110 + 116 + 134 120o

The average specific rate of oxygen sorption for this miniplast (according to VNIIGD) is 0 W 0, m3 / (kg s). Humidity coal W "0.07 fractions of volume. The thickness of the seam S is 1.4 m. The natural temperature of the rocks on the horizon of 660 m is 35 ° C.

The strike distance between the entry points to the developed space of wells II and VIII and 90 m, and the incidence of wells IV and V12 is 20 m.

The intensity of the foam is determined from the expression (1)

niitb + “oi

ha IQ-

1- - | Jei-e-eilTn + a.T .. -t ()

Where

104-0.33-10 6 (0.2-0.08)

but

(In 0.2 - In 0.08) (0.06 + 0.07)

i- 7

.4 (05071 + 0.06) —in 69 0 "3 120-10 6 (for K 90 foam multiplicity),

.... 1, -80 (70440}

 10.i. | „I X .. M-HO) 3104-068 120

(1st + Ov -13E) "G4 1fM-v" -18v) JS + Ш 1КГ | + 1в

Foam into the space developed is supplied by wells II. IV, VIII. Filling

The space developed by the foam was carried out using two foam generators UTI (developed by VNIIGD). providing a total feed of 1200, i.e. 600 m / h each.

After the beginning of filling the worked-out area with foam, the efficiency of processing the fire-hazardous zone is monitored hourly by taking air samples from the jet outgoing from the source of fire.

for the maintenance of O2, CO, H2. C02 and CH4. After 3 h, the volume dol, 00159%; C02 0.9%; 02 17%; H2 0%; CH4 1.7%, indicating no burning. Continuing to feed into the space

foam, measuring the temperature in the developed space with the help of UKTS in wells III, VI and VII. It turned out that He - 58 ° C; Tovi - 60 ° С and T0vn 64 ° С. Repeated temperature measurements in these

wells are made every hour and only after 7 hours of continuous foam supply the temperature in these wells is reduced to 35 ° C. Then after 6 hours, i.e. after the destruction of the foam in the developed space, temperature measurements are made in all nine wells, to ensure that the fire is localized and there are no relapses. The temperature in all wells does not exceed 35 ° C. Only after

of this, all work was stopped and the fire was classified as extinguished.

During 7 hours of fire extinguishing at a foam ratio of 90 and a foam former concentration of 2%, two foam generators consumed Vp - 7-1200 / 90 93 m3

foaming solution and Vn 0.01-2 93 1.9 m3 of frother.

Claims (1)

Claims The method of extinguishing endogenous fires in mined-out spaces of coal mines, includes drilling wells into the open space and supplying gas-mechanical foam through the wells, characterized in that, in order to increase the efficiency of extinguishing endogenous fires due to the intensification of heat removal, oxygen is determined before feeding the pench the air stream and the temperature of the fire center and surrounding rocks coming to the hearth and outgoing from the fire center, and the gas-mechanical foam is supplied with intensity, the defined by the following mathematical expression: Imlifll)  -fЈ Ј Ј | Јl + where I - the intensity of the foam, m / h; m - reservoir thickness, m; And - the distance along the strike between the points of entry of wells into the open space, in which the temperature is higher than the natural temperature of the rocks of the given horizon by 5 ° C, m; 2 is the distance between the points of entry of wells into the open space, in which the temperature is higher than natural for a given horizon at 5 ° C, 4 U (Co - C) "one (In Stock - In Sich) (0.06 + W) coefficient taking into account the generation of heat by the fire 1 25 03 m (w + 0.06) ° effecnt nt, five 0 five 0 taking into account removal of heat from the fire center by the collapsed rocks of the treated area, С 1; Oz - coefficient taking into account the removal of heat from the fire center foam, C, take, depending on the multiplicity of the resulting foam; Tom - the temperature of the fire, ° C; T0 - the temperature of the rocks surrounding the fire; Тг - natural temperature of rocks at a given depth of development, ° С; O is the average specific sorption rate of oxygen by coal, m3 / (kg s); Co is the concentration of oxygen in the stream of air entering the fire, the volume fraction; Six is the concentration of oxygen in the stream of air emanating from the fire, volume fraction; W - coal moisture in the emergency area, fractions of volume.