JP2014111720A - Method of splash prevention of powder dust and splash prevention agent of powder dust used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of splash prevention of a powder dust useful for splash prevention of the powder dust in an accumulation such as a carbonaceous material, a mineral and an inorganic material, also prevention of their adhesion to transfer equipment or obstruction of the transfer equipment, and to provide a splash prevention agent of the powder dust used therefor.SOLUTION: The above problem is solved by a method of splash prevention of a powder dust by bringing an aqueous solution containing polyethylene glycol having a number average molecular weight of 1000 to 2000 at a ratio of 0.01 to 5 mass% as a dust prevention component into contact with an accumulation selected from a carbonaceous material, a mineral and an inorganic material to prevent splash of the powder dust from the accumulation.

Description

  The present invention relates to a dust scattering preventing method and a dust scattering preventing agent used therefor. More specifically, the present invention relates to a dust scattering prevention method effective for preventing dust from scattering in deposits such as carbonaceous materials, minerals and inorganic substances, and thus preventing them from adhering to the transfer equipment and thereby blocking the transfer equipment. The present invention relates to an anti-dusting agent used for the dust.

Coal, coke, iron ore and coal ash at steelworks and thermal power plants, and earth and sand at construction sites and quarry sites are usually stored in a piled state. There was a problem that the work environment and the surrounding environment deteriorated due to scattering.
Conventionally, a large amount of water spraying has been repeated as a measure to prevent such dust scattering, but the surface of the piled deposit is usually hydrophobic, thus effectively preventing the generation of dust. It was difficult. Moreover, in these transfer facilities, problems such as deposits blocking the hopper and dust adhering to the belt conveyor have occurred.

On the other hand, in recent years, coal has been reviewed as an inexpensive fuel source from the viewpoint of stable energy supply, and in particular, demand for low-grade coals such as sub-bituminous coal and lignite, which have been low in utility value, has been increasing. However, these low-grade coals are easily oxidized, and if left in a silo for indoor storage for a long period of time, the inflow of air into the coal sediment causes the coal to undergo an oxidation reaction, and the reaction heat is accumulated. Problems such as spontaneous combustion of coal may occur.
Conventionally, as a measure for preventing such oxidation, measures such as coal pile re-loading and watering have been taken before the internal temperature rises, but it has been difficult to sufficiently prevent oxidation. Further, the oxidation of coal is a deterioration, that is, a reduction in calories as a fuel source, and a cost increase is also a problem.

In response to the above problems, measures have been proposed for preventing dust scattering and oxidation degradation.
For example, JP-A-56-67385 (Patent Document 1) discloses a dust prevention method in which a surfactant and a polyhydric alcohol are dispersed in an aqueous solution, and JP-A-57-98579 (Patent Document 2). Is a dust-preventing composition comprising a specific weight proportion of a polyoxyethylene-based nonionic surfactant, a sulfonate-type or carboxylate-type anionic surfactant, and a divalent to pentavalent polyol having a molecular weight of about 500 or less. JP-A-1-118589 (Patent Document 3) discloses a method for preventing dust from petroleum coke by spraying ammonium dialkylsulfosuccinate, polyoxyethylene nonionic surfactant and polyhydric alcohol as an aqueous solution. ing.
However, the aqueous solution and composition described above have a drawback that the permeability to the deposit is insufficient and the dust suppressing effect is insufficient.

JP-A-63-112307 (Patent Document 4) discloses a block copolymer type nonionic surfactant having a specific weight ratio of polyoxypropylene groups and polyoxyethylene groups, an SBR system, and A method of preventing the rainwater from penetrating into the sediment by uniformly spraying the acrylic emulsion latex on the field coal deposit in order to form a resin protective layer, that is, an alkyl ester nonionic interface between glycol and polyhydric alcohol A composition in combination with an active agent is disclosed. Further, JP-A-5-263086 (Patent Document 5) discloses a polyoxyalkylphenyl ether containing a specific amount of propylene oxide group and having a specific weight average molecular weight, a water-soluble amine compound showing basicity, and In a specific weight ratio, a composition comprising a combination of a glycol containing an oxypropylene group and a polyoxyalkyl phenyl ether nonionic surfactant is disclosed.
However, the above composition also has a problem that the permeability to the deposit is insufficient and the dust suppressing effect is insufficient.

JP-A-56-67385 JP-A-57-98579 Japanese Unexamined Patent Publication No. 1-185589 JP 63-112307 A Japanese Patent Laid-Open No. 5-263866

  Therefore, the present invention has been made in view of the above-described problems and current state of the prior art, and prevents dust from being scattered in deposits such as carbonaceous materials, minerals, and inorganic materials, and consequently adheres to the transfer equipment. It is an object of the present invention to provide a dust scattering prevention method and a dust scattering prevention agent used therefor that are effective in preventing blockage of a transfer facility.

In order to solve the above problems, the present inventors have conducted intensive research focusing on the molecular weight of polyethylene glycol, and as a result, found that polyethylene glycol having a specific number average molecular weight has a particularly excellent dust prevention effect, The present invention has been completed.
Until now, in this technical field, the molecular weight of polyethylene glycol as a dust prevention component has not been noticed, and it is a surprising fact that polyethylene glycol having a specific number average molecular weight has a particularly excellent dust prevention effect. is there.

Thus, according to the present invention, an aqueous solution containing 0.01 to 5% by mass of polyethylene glycol having a number average molecular weight of 1000 to 2000 as a dust prevention component is selected from carbonaceous materials, minerals and inorganic substances. A dust scattering prevention method is provided, wherein the dust scattering from the deposit is prevented by contacting with the deposit.
Moreover, according to this invention, the dust inhibiting agent used for said dust scattering prevention method is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the dust scattering prevention method effective in prevention of dust scattering in deposits, such as a carbonaceous substance, a mineral, and an inorganic substance, and also adhesion to those transfer equipment, and the obstruction | occlusion of a transfer equipment by it, and it uses for it A dust scattering inhibitor can be provided, and the present invention is extremely useful in industry.

When the dust scattering prevention method of the present invention satisfies at least one of the following requirements:
When the aqueous solution further contains at least one selected from sodium polyacrylate, polydiallyldimethylammonium chloride, epichlorohydrin and polyoxyethylene lauryl ether as the second dust prevention component,
When the mass ratio of the polyethylene glycol and the second dust prevention component is 100: 1 to 1: 1,
When the aqueous solution consists of bringing the aqueous solution into contact with the deposit by spreading the aqueous solution over the deposit,
When the deposit is at least one selected from coal, coal coke and iron ore,
The above effects are further exhibited.

It is the schematic of the apparatus for measuring the dust density | concentration and dust amount of coke powder. It is a figure which shows a time-dependent change of the dust density | concentration immediately after forcible scattering of coke powder (Test example 1). It is a figure which shows the load average dust amount (TWA) after 1500 second from forced scattering of coke powder (Test Example 1). It is a figure which shows a time-dependent change of the dust density | concentration immediately after forcible scattering of coke powder (Test example 3). It is a figure which shows the load average dust amount (TWA) after 1500 second from forced scattering of coke powder (Test Example 3). It is a figure which shows a time-dependent change of the dust density | concentration immediately after forced scattering of iron ore powder (Test Example 4).

  The dust scattering prevention method of the present invention comprises an aqueous solution containing polyethylene glycol having a number average molecular weight of 1000 to 2000 as a dust preventing component in a proportion of 0.01 to 5% by mass from a carbonaceous material, a mineral and an inorganic substance. It is made to contact the selected deposit, and scattering of the dust from the said deposit is prevented, It is characterized by the above-mentioned.

The dust preventing component used in the method of the present invention is polyethylene glycol having a number average molecular weight of 1000 to 2000.
In the present invention, the number average molecular weight means a value obtained from a hydroxyl value.
Specifically, the number average molecular weight is, for example, polyethylene determined by an acetic anhydride / pyridine method such as Japanese Industrial Standard JIS 1557-1: 2007 corresponding to the international standard ISO 14900: 2001, and method A for determining the hydroxyl value. It means a value obtained from the hydroxyl value of glycol.

When the number average molecular weight of the polyethylene glycol is in the above range, an excellent dust prevention effect is exhibited. The number average molecular weight of polyethylene glycol is more preferably 1000-1500.
As the polyethylene glycol, commercially available products as described in Examples can be used.

The aqueous solution used in the method of the present invention contains a dust prevention component in a proportion of 0.01 to 5% by mass.
When the content ratio of the dust prevention component is less than 0.01% by mass, the amount of the aqueous solution sprayed increases and the water content of deposits such as coal and iron ore increases, which may facilitate adhesion to the transfer equipment. . In addition, when there is a heating facility such as drying in the subsequent stage, the amount of heat required increases, which may increase the fuel cost. On the other hand, if the content of the dust prevention component exceeds 5% by mass, if the amount of the aqueous solution sprayed is not sufficient for economic reasons, the spraying may be uneven and a sufficient dust prevention effect may not be obtained. .

A preferable content ratio of the dust prevention component is 0.02 to 1.0% by mass, and more preferably 0.03 to 0.5% by mass in consideration of the obtained effect and economy.
The aqueous solution can be obtained by diluting the dust prevention component with a solvent such as water so as to have the above-mentioned content ratio.

  The aqueous solution used in the method of the present invention may further contain at least one second dust prevention component as a dust prevention component. Examples of such second dust prevention component include sodium polyacrylate, poly Examples include diallyldimethylammonium chloride, epichlorohydrin and polyoxyethylene lauryl ether. These second dust-preventing components are particularly preferable in the case where hydrophobic deposits are targeted, because the aqueous solution to be sprayed becomes easier to adapt to the deposits.

Higher alcohol surfactants other than the above polyoxyethylene lauryl ether can also be used in combination with polyethylene glycol.
Examples of such higher alcohol surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, polyoxyethylene polyhydric alcohol fatty acid ester, polyoxyethylene alkylamine, polyoxyethylene. And fatty acid amides.

The aqueous solution used in the method of the present invention contains the dust prevention component in a proportion of 0.01 to 5% by mass, but when it further contains at least one second dust prevention component, The dust prevention component is contained in the above ratio as a total amount.
At this time, the mass ratio of the essential component polyethylene glycol and the second dust prevention component is preferably 100: 1 to 1: 1, more preferably 10: 1 to 1: 1.
Even when the aqueous solution further contains the second dust prevention component, the aqueous solution can be obtained by diluting the dust prevention component with a solvent such as water so as to have the above mass ratio.

In the method of the present invention, the aqueous solution is brought into contact with the deposit, but the method is not particularly limited, and may be appropriately selected depending on the state of the deposit and the surrounding conditions. From the viewpoint of obtaining a uniform dust scattering prevention effect and workability, it is preferable to spray the aqueous solution on the deposit, and it is particularly preferable to spray the deposit so as to spray uniformly.
In the method of the present invention, two or more kinds of dust prevention components may be prepared as separate aqueous solutions, and may be simultaneously or separately brought into contact with the deposit. However, it is possible to obtain a uniform dust scattering prevention effect and workability. In view of the above, it is preferable to prepare a one-part aqueous solution and contact the deposit.

In the method of the present invention, the amount of the aqueous solution to be brought into contact with the deposit may be appropriately set according to the type of the target deposit, the amount of dust expected to be scattered, etc., and considering the economy. Good.
Usually, the amount of the aqueous solution is about 2.4 × 10 ^{−4 to} 4.5 × 10 ⁻⁴ mass% with respect to the mass of the deposit.

The deposit to be prevented from scattering in the method of the present invention is selected from carbonaceous materials, minerals and inorganic materials. Specific examples include coal, coal coke, ore, iron ore, crushed stone, and earth and sand.
Among these, at least one selected from coal, coal coke, and iron ore is particularly preferable because the excellent effects of the present invention are particularly easily obtained. That is, according to the method of the present invention, scattering of coke powder from coal coke and iron ore powder from iron ore can be efficiently prevented.
The average particle size of the dust in the deposit is, for example, about 45 to 65 μm in the case of coke powder, although it depends on the type.
The temperature of the deposit is generally 50 ° C. or more, and in the case of coke powder transported by a belt conveyor, it is generally about 150 to 200 ° C.

The present invention will be specifically described with reference to test examples, but the present invention is not limited to these test examples.
In the test examples, the compounds shown in the following table were used.

Test Example 1 (Coke powder scattering prevention effect confirmation test)
250 g of coke powder (average particle size of about 45 to 65 μm) collected at Sakai Steel Works was placed in each of the number of test specimens made of metal (150 mm × 100 mm × height 30 mm, volume 450 mL).
Next, the drug Nos. Shown in Table 1 prepared in advance were prepared. 1 to 7 of 5 mass% aqueous solution 25 mL (0.5 mass% with respect to the mass of coke powder) was mixed with the coke powder stored in a metal container using a commercially available sprayer (sprayed with aqueous drug solution), and the temperature was 100 The coke powder was dried for about 1 hour in a thermostatic chamber set to ° C.
For comparison, a test solution without water treatment (Blank) and a test solution using the same amount of water instead of the water solution (Water) were tested.

Next, about 250 g of the dried coke powder is installed in an apparatus for measuring the dust concentration (mg / m ³ ) and the dust amount (mg / m ³ ) shown in FIG. Blow at a rate of 18 L / min for 3 seconds to forcibly disperse the coke powder, and measure the dust concentration and dust amount over time for 25 minutes (1500 seconds) immediately thereafter to evaluate the anti-scattering effect of each drug. did. The results obtained are shown in FIGS.

  The apparatus of FIG. 1 consists of a main body of a plastic container 1 (300 mm × 150 mm × height 250 mm, volume 11250 mL). On the upper surface of the plastic container 1, there is provided a blow hole 3 (nozzle diameter 2.0 mm of the air compressor 2) for blowing air to the coke powder using an air compressor 2 (manufactured by KNO, model number: 02-04N), Inside the plastic container 1 for installing the sensor unit of the dust meter 4 (manufactured by Transtec Co., Ltd., model: Dust Track II HC-Model 8531) at a position facing the air blowing hole 3 with respect to the long side of the plastic container 1 A communicating cylinder 5 (inner diameter 40 mm × length 500 mm) is provided, and an inclination 6 for assisting the scattering of coke powder is provided immediately below the blow hole 3 on the lower surface of the plastic container 1.

The inclination 6 extends to the side surface of the plastic container 1 on the lower surface of the plastic container 1 in a direction orthogonal to the straight line connecting the air blowing hole 3 and the cylinder 5, It is provided so as to descend from the height 30 mm) toward the bottom surface (vertical length 150 mm) of the plastic container 1 on the cylinder 5 side.
Further, a measurement port 7 (inner diameter: 10 mm) for setting a sensor unit of the dust meter 4 is provided at the top end of the cylinder 5.
In the measurement, coke powder was installed in the figure 8 of FIG.

FIG. 2 is a diagram showing the change over time in the dust concentration immediately after the forced scattering of coke powder (up to 1500 seconds (s)).
According to FIG. 3> No. 4> No. 5> No. 7> No. 6> No. 1 ≒ No. It can be seen that 2> Blank = Water.
FIG. 3 is a diagram showing a load average dust amount (TWA) after 1500 seconds from the forced scattering of the coke powder.
According to FIG. 3, the drug No. 1 containing polyoxyethylene glycol having number average molecular weights of 1000, 1450 and 2000, respectively. It can be seen that 3 to 5 have a particularly excellent coke powder scattering prevention effect.
When the amount of blank dust is 100, the drug No. The amount of dust of 3 to 5 is about 70, and a reduction of 30% in the amount of dust means that the generation of dust itself was suppressed by the chemical, which proves extremely effective in preventing dust scattering.

Test example 2 (coke powder scattering prevention effect confirmation test)
In a coke transfer conveyor at Sakai Steel Works, a chemical aqueous solution having the conditions shown in Table 2 was sprayed, and the degree of dust generation at the downstream conveyor switching unit was measured with a dust meter (manufactured by Transtec Corporation, model: Dust Track II HC-Model 8531). ) Was used for continuous measurement.
For comparison, a test solution without water treatment (Blank) and a test solution using the same amount of water instead of the water solution (Water) were tested. The obtained results are shown in Table 2.

  According to Table 2, no. It can be seen that a sufficient inhibitory effect is exhibited under the condition that 0.01% by mass or more of the 3 aqueous drug solutions are contained as dust prevention components. No. 3 and the known surfactant No. 9 or No. It can be seen that the combination with No. 10 exhibits a further excellent anti-coke powder scattering preventing effect.

Test Example 3 (Coke powder scattering prevention effect confirmation test)
As the aqueous drug solution, the drug No. 1 shown in Table 1 was used. A mixed aqueous solution (mixing ratio 1: 1, dust prevention component 5 mass%) prepared by adding 5 mass% aqueous solutions of known surfactants Nos. 8 to 9 and 12 shown in Table 1 to 5 mass% aqueous solution 3 ), And a mixed aqueous solution (mixing ratio 10: 1, dust prevention component 2.75% by mass) prepared by adding 0.5% by mass aqueous solutions of known surfactants No. 10 and 11 shown in Table 1 respectively. Except that, the scattering prevention effect of each drug was evaluated in the same manner as in Test Example 1. The obtained results are shown in FIGS.

FIG. 4 is a diagram showing the change over time in the dust concentration immediately after the forced scattering of coke powder (up to 1500 seconds (s)).
According to FIG. 4, the effect of preventing the scattering of coke powder is as follows. > (No. 3 + No. 12)> No. It can be seen that the order is 3.
FIG. 5 is a diagram showing a load average dust amount (TWA) after 1500 seconds from forced scattering of coke powder.
According to FIG. 5, a polyoxyethylene glycol drug No. 1 having a number average molecular weight of 1000 is shown. It can be seen that the combination of No. 3 and known surfactants Nos. 8 to 12 exhibits a further excellent coke powder scattering prevention effect.

Test Example 4 (Iron Ore Powder Scattering Prevention Effect Confirmation Test)
The anti-scattering effect of each drug was evaluated in the same manner as in Test Example 1 except that iron ore powder (average particle size of about 45 to 65 μm) collected from Sakai Works was used instead of coke powder. However, no. 1 and no. Only 3 to 6 drug aqueous solutions and (No. 3 + No. 10) mixed aqueous solution, as compared with Blank and Water, were tested. The obtained result is shown in FIG.

FIG. 6 is a diagram showing a change over time in the dust concentration immediately after the forced dispersion of iron ore powder.
According to FIG. 6, the effect of preventing the scattering of coke powder is as follows: (No. 3 + No. 10)> No. 3> No. 4> No. 5> No. 6> No. It is understood that the order of 1>Water> Blank, and the dust scattering preventive agent of the present invention exerts the scattering preventing effect on iron ore powder as well as the coke powder.

  In addition, as a result of testing with an actual machine, it was possible to confirm the dust scattering suppression effect on coke powder and iron ore powder (including sintered ore powder) at 100 to 200 ° C.

DESCRIPTION OF SYMBOLS 1 Plastic container 2 Air compressor 3 Ventilation hole 4 Dust meter 5 Cylinder 6 Inclination 7 Measuring port 8 Coke powder

Claims (6)

  An aqueous solution containing polyethylene glycol having a number average molecular weight of 1000 to 2000 as a dust prevention component in a proportion of 0.01 to 5% by mass is contacted with a deposit selected from a carbonaceous material, a mineral and an inorganic material, 2. A method for preventing dust scattering, wherein dust scattering from the deposit is prevented.   The aqueous solution further contains at least one selected from sodium polyacrylate, polydiallyldimethylammonium chloride, epichlorohydrin and polyoxyethylene lauryl ether as a second dust prevention component. Dust scattering prevention method.   The dust scattering prevention method according to claim 2, wherein a mass ratio of the polyethylene glycol and the second dust prevention component is 100: 1 to 1: 1.   The dust scattering prevention method according to any one of claims 1 to 3, wherein the aqueous solution is brought into contact with the deposit by spraying the aqueous solution onto the deposit.   The method for preventing dust scattering according to any one of claims 1 to 4, wherein the deposit is at least one selected from coal, coal coke, and iron ore.   The dust prevention agent used for the dust scattering prevention method as described in any one of Claims 1-5.