JPH0662974B2 - Method for preventing oxidative deterioration and spontaneous combustion of piled coal piles - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for preventing oxidative deterioration and spontaneous combustion of piled coal piles stored in a raw material yard of an iron mill or the like.

<Prior Art> Raw coal in iron mills is classified into various types and stored in piles in a yard.

Depending on the type of coal, the above-mentioned coal piles may be stored in a piled state as described above for a long period of several months before use, and since they are in contact with the atmosphere during storage, Since the carbonaceous matter and the sulfur content react with oxygen in the atmosphere and the reaction is an exothermic reaction, the heat quantity stored in the coal gradually increases with the passage of time by accumulating reaction heat.

Moreover, since coal is black, the radiant heat from the sun is easily absorbed as a large amount of heat.

When the amount of heat due to the above-described oxidation reaction and the amount of heat due to the radiant heat of the sun are stored inside the coal mine and reach the limit temperature, spontaneous ignition may occur. When such spontaneous combustion occurs, the cost loss such as burned coal and accident disposal will be enormous.

Further, even if the spontaneous combustion as described above is not achieved, the quality of the coal in the coal pile is remarkably deteriorated by the above-mentioned oxidation, and the heat loss becomes enormous.

Conventionally, in order to prevent the spontaneous combustion described above, a means for dissipating the heat quantity inherent in the coal mountain into the atmosphere by collapsing the coal mountain and redepositing it at another place has been adopted,
This is a method with low work value because it requires a huge amount of work and has no effect on the above-mentioned deterioration due to oxidation.

Therefore, various methods for suppressing the oxidation of coal by suppressing the ventilation of air to the coal pile have been studied, for example, JP-A-51-1377.
No. 01 publication, a method of spraying a resin coating agent on the surface of the deposited coal pile, mixing dry ice in advance to the bottom of the coal pile to generate carbon dioxide, or JP-A-59 -27991, a method of generating an inert gas from the bottom to replace oxygen inside the coal mine, or a method of injecting water into the coal mine ("Thermal Nuclear Power Generation" Vol. 33, (1982) No. 4), etc. have been proposed and implemented in part.

<Problems to be Solved by the Invention> However, in the method of spraying the above resin coating agent, it is difficult to block oxygen because a large number of small holes are formed in the resin coating, and dry ice or an inert gas is also used. The method described in (1) above is enormous in cost, and further, the method of injecting water causes a problem that a drying step is required before use and combustion efficiency is lowered because the water content of coal increases.

<Means for Solving the Problems> The present invention has been proposed in view of the above, and sprays a resin solution containing a white powder on the surface of an open coal pile,
By forming a white coating film, air circulation and heat absorption are suppressed to prevent oxidative deterioration and spontaneous combustion of the piled coal pile.

According to the present invention described above, a white coating film can be formed by spraying a resin liquid containing a white powder on the surface of a black coal pile and drying the resin liquid.

The above-mentioned white powder used in the present invention may be of any type as long as it can be uniformly mixed with the resin liquid, and examples thereof include magnesium hydroxide, magnesium carbonate, calcium hydroxide and carbonate. There are calcium, titanium oxide, etc., and among them, titanium oxide is good, and the concentration is not limited, but from the viewpoint of effects such as airtightness and hiding property and economical efficiency, 1 to 30% by weight, preferably A content of 3 to 10% by weight is preferable, and if it is 1% or less, it is not a resin layer and the underlayer is transparent, and if it is 30% or more, it is economically unsuitable.

The resin of the resin liquid is not particularly limited, but acrylic resin, vinyl acetate resin, polyethylene resin, polyester resin or the like can be used, and the resin concentration of the resin liquid is 3 to The content is preferably 30% by weight, preferably 5 to 15% by weight, and when it is 3% or less, the resin layer is thin and easily cracked, and when it is 30% or more, it is economically unsuitable.

<Function> When the white powder described above is sprayed with the resin liquid on the surface of the coal mine and dried to form a film, the white powder is contained in the film, so that it is not exposed to the wind and rain and does not flow out. The surface of the coal pile can be kept white for a long time.

The resin liquid mixed with the white powder as described above has a film-forming property, and it is desirable to use a resin having low air permeability when formed as a film, and the resin is dissolved in an organic solvent or water. Alternatively, it is an emulsified solution or emulsion.

When white powder is mixed and dispersed in the above resin liquid and sprayed on the surface of the coal mine, the white powder particles block many small holes formed in the resin coating when only the resin liquid is sprayed, and the air flow It is possible to form an airtight white coating film that surely blocks the above, and it is possible to suppress the reaction between the carbonaceous matter and the sulfur content in the coal and the oxygen in the atmosphere.

In addition, since the film formed when only the resin liquid is sprayed is transparent, sunlight passes through, and the black coal mountain absorbs thermal energy such as infrared rays and the temperature rises. However, in the present invention, since the white coating film covers the surface of the coal mountain, it is possible to suppress sunlight from being reflected and the coal mountain absorbing heat to raise the temperature.

As described above, according to the present invention, air flow and heat absorption can be suppressed only by spraying the resin liquid containing the white powder.

Therefore, by suppressing the circulation of air, the oxidative deterioration of coal is prevented, and by suppressing the heat absorption and suppressing the circulation of air, spontaneous combustion is prevented.

Further, according to the present invention, in the operation of spraying the resin liquid containing the white powder onto the coal hill, the color of the coal hill when a coating having a thickness of about a certain amount is applied is white, Since the unsprayed part is black, which is the ground color of coal, there is no overlap in spraying or forgetting to scatter due to the difference in surface color.

Furthermore, when the amount of the resin liquid containing the white powder is small, since the white coating film formed is thin, the color of the film becomes pale white, and the surface of the coal pile after treatment becomes gray. . However, when the amount of the resin liquid containing the white powder sprayed is large, the white coating film formed is thick and the color of the film is dark white, and the surface of the coal pile after the treatment is white.

Therefore, by adjusting the color of the surface of the coal pile after spraying the resin liquid containing the white powder as described above, the spray amount can be adjusted, or a white coating film having a uniform thickness can be formed by overcoating. Can be formed.

As described above, according to the present invention, a white coating film can be uniformly formed on the surface of the coal pile, and
It is possible to confirm that the treatment has been performed from a distance, and even if a crack occurs in the white coating film, it can be easily found because the film is white, and it can be easily repaired by applying multiple layers. it can.

In addition, the whitened coal mine according to the present invention can be confirmed to have been treated from a distance as described above, and thus not only brings an effect in the management and use of the coal mine, but also a visual effect. It has the effect of improving aesthetics. And, whereas the untreated coal mountain was a huge black block and gave a very negative impression, the whitened coal mountain obtained by the present invention impairs the natural aesthetics. There is no such thing, and it is possible to eliminate the negative impression.

To <Example> Coal mountain is coal species Chinese coal 10,000tCO2 (spraying area 2,400 m ^2), and an application rate of spray liquid 1.5 / m ² of formulation of Examples 1-5 and Comparative Examples are shown in Table 1 It was evenly sprayed.

Thermocouples were buried in the upper and lower portions of the coal piles sprayed with the spray liquids of Examples 1 to 5 and Comparative Example, respectively, each having a length of 3 m, and the compensating conductors derived from the thermocouples were connected to a portable thermocouple thermometer. The temperatures of the upper part and the lower part of the coal mine were measured every day (60 days) for a predetermined time, and the average temperature is shown in Table 1, and the oxidative deterioration of coal was visually observed and shown in Table 1.

From Table 1, when the spray liquids of Examples 1 to 5 are sprayed, the temperature inside the coal pile can be kept low, and the temperature is lower by about 5 ° C in the upper part and 10 ° C or more in the lower part than the untreated comparative example. I was able to suppress it.

Further, by spraying the spray liquid of Examples 1 to 5, a white coating is formed on the surface of the coal mine, and the presence or absence of the white coating can be confirmed from a distance, so the spraying work should be performed without duplication. You can Further, the spray liquid could be uniformly sprayed by the shade of white without causing uneven scattering in which the thickness of the white coating was partially different.

<Effects of the Invention> As described above, according to the present invention, it is possible to prevent oxidative deterioration and spontaneous combustion of a coal hill by suppressing the circulation and heat absorption of air in the piled coal mine.

In addition, since it is possible to easily confirm the sprayed portion of the white resin liquid, it is possible to perform the spraying work without duplication and without forgetting to spray.

Furthermore, since the uneven distribution of the white coating film does not occur due to the density of the white coating film, it is possible to perform a uniform spray coating with a certain thickness or more, so that airtightness and heat reflectivity can be retained on the entire surface of the coal mountain to oxidize It is possible to prevent deterioration and spontaneous ignition.

In addition, the whitened coal mine according to the present invention does not impair the aesthetics of nature and can wipe away the conventional negative impression.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takamasa Ishioka 9 Kirihara Town, Fujisawa City, Kanagawa Prefecture, Central Research Institute of Taiho Industrial Co., Ltd. Central Research Laboratory (56) Reference JP-A-51-137701 (JP, A) JP-A-51-89536 (JP, A)

Claims (1)

[Claims] 1. A method for preventing oxidative deterioration and spontaneous ignition of an open coal pile, which comprises spraying a resin solution containing a white powder on the surface of an open pile of coal to form a white coating film. .