JP5412781B2 - Method for improving bulk density of coal for coke production - Google Patents

Description

  The present invention relates to a method for improving the bulk density of coal for producing coke, and in particular, in a coal transport line charged into a coke oven, a bulk density improver is added to the coal being transported to increase the bulk density of the coal. The present invention relates to a method for efficiently performing a bulk density improvement effect by a bulk density improver.

  The demand for coke, one of the raw materials for blast furnaces, has been increasing along with the increase in crude steel production due to the booming steel industry, and there is a need for improved productivity of coke produced by dry distillation of coal. It has been.

  Examples of means for improving coke productivity include a method of increasing the bulk density of coal charged into the coke oven and increasing the amount of raw coal charged into the coke oven.

  Conventionally, as methods for improving the bulk density of coal for coke production, the following methods have been developed, but none of these effects have been fully satisfactory.

(1) Molded coal blending method: A method of improving the bulk density of a molded part by blending a pressure-molded coal.
This method has a problem of a decrease in bulk density due to a significant increase in the moisture content of coal during rainfall.

(2) Coal humidity control method or DAPS method (fine-pulverized agglomerated coal blending method): A method of increasing the bulk density by drying coal and reducing the water content of the coal.
In these methods, there is a limit to the reduction of the amount of water by drying, and in any method, there is a problem that the moisture content of coal increases and the bulk density decreases during rainfall.

(3) A method of adding mineral oil such as heavy oil or oil such as waste oil to coal.
In this method, mineral oil such as heavy oil and waste oil are added to the coal to improve the filling (bulk density) of the coal when it is charged into the coke oven by accelerating the slip between the coal particles. However, there is a drawback that a sufficient bulk density improvement effect cannot be obtained for coal with a high water content.

(4) A method of adding a surfactant as a bulk density improver to coal (for example, Patent Document 1).
With this method, it is possible to obtain an effect of improving the bulk density even for high moisture content coal, but in the conventional method, an effect of improving the bulk density commensurate with the amount of the added bulk density improver is obtained. Is hard to say.

Conventionally, a bulk density improver such as a surfactant is added to coal in a transport line on the upstream side of the pulverizer.
That is, the coal transportation line for charging the coke production coal into the coke oven transports the blended coal raw material from the blending tank 1 to the pulverizer 2 by a belt conveyor as shown in FIG. After being pulverized by the machine 2, it is transported to the coke oven 3 by a belt conveyor and charged. In addition, as shown in FIG. 2, there is a case where the humidity control equipment 4 is provided in the transport line from the pulverizer 2 to the coke oven 3. It is added with respect to the coal on the belt conveyor of the upstream of the grinder 2 shown by A point.

This is because when the coal is pulverized in the pulverizer 2, the bulk density improver added to the coal on the upstream belt conveyor is sufficiently uniformly mixed with the coal in the pulverizer 2. The patent document 1 also describes that it is added to the raw coal before being pulverized.
In FIGS. 1 and 2, T indicates a connecting portion of the belt conveyor, and a white arrow indicates a transport direction.
JP 2007-63420 A

  As described above, by adding a bulk density improver to coal, an effect of improving the bulk density can be obtained even for coal with a high water content, but the bulk density improving effect by the bulk density improver is sufficient in the conventional method. Even if the same bulk density improver is used, the bulk density improving effect is more effectively exhibited, and the higher bulk density can be achieved with a smaller amount of added bulk density improver. A method for obtaining a density enhancement effect is desired.

  Therefore, the present invention provides a method for improving the bulk density of a coal by increasing the bulk density of the coal by adding a bulk density improver to the coal being transported in the coal transportation line charged in the coke oven. It is an object of the present invention to provide a method for effectively performing an effective process.

In the method for improving the bulk density of coal for producing coke according to the present invention (Claim 1), the bulk density of the coal is obtained by adding a surfactant to the coal being transported in the coal transport line charged in the coke oven. In this method, the transport line is configured to transport the coal to a coke oven through a pulverizer and a humidity control equipment provided at the subsequent stage, and the pulverizer has a particle size of 3 mm or less. % , The surfactant is added to the coal pulverized so as to be equal to or greater than% in the upstream of the humidity control equipment .

Claim 2 of the co - bulk density method for improving coal for box manufacturing, in claim 1, the upstream side or downstream side of said timing wet coal facilities, by further adding a surfactant, the surfactant It is characterized by being added to two places on the pulverized coal transportation line.

U claim 3 - bulk density method for improving coal for box manufacturing, in claim 1 or 2, wherein the surfactant is characterized by an aqueous solution of the active ingredient concentration 5-15 wt%.

  According to the present invention, the bulk density of coal pulverized so that the particle size is 3 mm or less (hereinafter, this particle content may be referred to as “−3 mm particle content”) is 75% or more. By adding the improver, the effect of improving the bulk density by the bulk density improver can be effectively exhibited. For this reason, compared with the conventional method of adding a bulk density improver to the coal before pulverization, the bulk density of the coal can be greatly improved at the same bulk density improver addition amount, and as a result, the bulk density improver usage amount This can reduce the processing cost and improve the productivity.

  In the present invention, by adding the bulk density improver to the coal after pulverization, the reason why the bulk density improvement effect superior to the case of adding the bulk density improver to the coal before pulverization is obtained is as follows. Can be considered.

  That is, the surface area of coal is greatly different between before and after pulverization, and it is more efficient to add the bulk density improver to the coal surface when adding a bulk density improver to the coal with a large surface area generated by pulverization. Can be made to act.

  In particular, even more excellent effects can be obtained by dividing and adding the bulk density improver at two locations to the pulverized coal, for the following reason.

  That is, when the bulk density improver is added at one location, the chemical is added from one direction to the coal surface, and the chemical is allowed to act on one side of the coal. In this case, the area on which the chemical is directly sprayed on the coal surface is increased, and the bulk density is easily improved on the entire coal. Moreover, the water adhering to the hydrophilic part of the coal surface spreads to the hydrophilic part and the hydrophobic part by adding the bulk density improver at the first place, and the bulk density improver easily spreads to the coal using water as a medium. Thus, the addition of the bulk density improver at the second location causes the bulk density improver to diffuse throughout the coal using the expanded water as a medium, and it is considered that a high bulk density improvement effect can be exhibited.

  Hereinafter, embodiments of the method for improving the bulk density of coal for producing coke according to the present invention will be described in detail.

  The method for improving the bulk density of coal for producing coke according to the present invention is to add a bulk density improver to coal pulverized so that the -3 mm particle size is 75% or more. For example, FIG. In the actual coal transport line shown in FIGS. 2 and 2, for example, the bulk density improver can be added to point B, or point B and point C or point D of the transport line downstream of the pulverizer 2.

  That is, in the present invention, the coal pulverized by the pulverizer 2 is added with the bulk density improver before being charged into the coke oven 3, but after the bulk density improver is added, It is preferable to add a bulk density improver to the upstream side of the portion where the mixed action acts on the added bulk density improver and coal as in the wet coal facility 4.

  Therefore, when adding the bulk density improver at one location on the downstream side of the pulverizer 2, it is preferable to add the bulk density improving agent on the upstream side of the connecting portion T or the humidity control equipment 4, as shown in FIGS. In addition, it is preferable to add a bulk density improver to the coal on the belt conveyor at point B at the outlet of the pulverizer 2 or point C at the inlet of the humidity control equipment 4.

  Further, when the bulk density improver is added at two locations downstream of the pulverizer 2, for the same reason as above, as shown in FIG. A bulk density improver is added to the coal (first bulk density improver addition point: hereinafter referred to as “No. 1 addition point”). It is preferable to add a bulk density improver at the point C or D beyond the connecting portion T (the second bulk density improver point: hereinafter sometimes referred to as “No. 2 addition point”). .

  Moreover, as shown in FIG. 2, in the transport line having the humidity control equipment 4, the bulk density improver is added to the coal on the belt conveyor at the B point at the outlet of the pulverizer 2 (No. 1 addition point), Furthermore, it is preferable to add a bulk density improver at the point C on the inlet side or the point D on the outlet side of the humidity control equipment 4 (No. 2 addition point).

  In this way, by adding the bulk density improver upstream of the humidity-controlling coal facility 4 having a large mixing action, the coal and the bulk density improver are uniformly mixed in the humidity-controlling coal facility 4 so as to have a high bulk density. An improvement effect can be obtained.

  The bulk density improver may be added to the coal on the belt conveyor at the upstream point C and the downstream point D of the humidity control equipment 4, and even in this case, the humidity control equipment The bulk density improver added on the downstream side of 4 can be sufficiently mixed with coal in the connecting portion T at the subsequent stage.

  In the present invention, a bulk density improver may be added at three locations downstream of the pulverizer 2, but excessively increasing the number of chemical injection points is not preferable in terms of work, and chemical injection at two locations. Since a sufficient effect can be obtained, the bulk density improver is preferably added to one or two locations on the downstream side of the pulverizer 2.

  Further, it is conceivable to add a bulk density improver on the downstream side of the pulverizer 2 and on the upstream side of the pulverizer 2, but as shown in Examples 6 to 9 described later, on the upstream side of the pulverizer 2. Since the effect of improving the bulk density is low as in the conventional method, it is preferable to add the bulk density improver only on the downstream side of the pulverizer 2.

  In the present invention, the degree of pulverization of coal to which the bulk density improver is added may be such that the -3 mm particle size is 75% or more. If the -3 mm particle content is less than 75%, the effect of the present invention by adding a bulk density improver to the pulverized coal cannot be sufficiently obtained. However, if the -3 mm particle size of the coal to which the bulk density improver is added is excessively high, the bulk density of the pulverized coal itself is reduced, so that even if the bulk density improvement effect by the bulk density improver is large, it is sufficient. The bulk density may not be increased. Therefore, the -3 mm particle size of coal to which the bulk density improver is added is preferably 75% or more and 85% or less. As long as the -3 mm particle size is within this range, there is no particular limitation on the particle size of the other coals, but the raw coal generally provided as coal for producing coke has a -3 mm particle size. The coal obtained by pulverizing with a pulverizer so as to be 75 to 85% has other particle sizes of approximately 5 mm or less.

  In addition, although there is no restriction | limiting in particular about the moisture content of this coal, It is preferable that it is about 7 to 15 weight%.

  In the present invention, the bulk density improver to be added to coal is not particularly limited, but a surfactant is preferable. For example, dialkylsulfosuccinic acid (the alkyl group preferably has 8 to 16 carbon atoms) or a salt thereof. (For example, sodium salts, ammonium salts, potassium salts, triethanolamine salts), nonionic surfactants such as polyoxyethylene alkyl ether sulfates, polyoxyethylene (POE) addition polymers or salts thereof A surfactant or the like can be used.

  These may be used alone or in combination of two or more.

  The addition amount of such a bulk density improver (the total addition amount when added at two locations) is 0.003 to 0.1% by weight, particularly 0.02 to 0.1%, as the amount of the active ingredient relative to coal. It is preferable to set it as 05 weight%. If the amount added is too small, a sufficient bulk density improving effect cannot be obtained, and if it is too large, the bulk density improving effect will reach its peak and the amount of drug injection will increase undesirably.

  In addition, when the bulk density improver is added at two locations, there is no particular limitation on the amount of each bulk density improver added, and it varies depending on the presence or absence of the subsequent humidity conditioning equipment and the number of connecting parts. In the case of No. 1, the ratio of the bulk density improver addition amount at the first location (No. 1 addition point) and the bulk density improver addition amount at the second location (No. 2 addition point) is No. 1. 1 addition point: No. It is preferable to add so that it may become 2 addition points = 3: 1-1: 3 (weight ratio).

  The aforementioned bulk density improver such as a surfactant is diluted with water and added to and mixed with coal as an aqueous solution. This is preferable for obtaining sufficient mixing with coal. In this case, the concentration of the active ingredient is 5 to 5. It is preferably added to coal as an aqueous solution having a moderate concentration of 15% by weight, particularly 8 to 12% by weight. If this concentration is too high, the effect of improving the mixing property with coal by dilution cannot be obtained sufficiently, and if it is too low, the moisture content increases, causing an increase in the heat of dry distillation in the coke oven and a decrease in the effect of improving the bulk density. .

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

  In the following, coal and bulk density improvers used in the bulk density improvement test are as follows.

[Sample charcoal]
The particle size distribution includes 40% of particles having a particle size exceeding 3 mm, 35% having a particle size exceeding 1 mm and 3 mm or less, and 25% having a particle size of 1 mm or less (-3 mm particle size: 60%) Coal for producing coke with a moisture content of 9% by weight.

[Bulk density improver]
Polyoxyethylene alkyl ether sulfates In adding this bulk density improver to coal, chemicals a to d comprising aqueous solutions having the following concentrations were prepared and used.
Drug a: 10% strength aqueous solution Drug b: 30% strength aqueous solution Drug c: 15% strength aqueous solution Drug d: 7.5% strength aqueous solution

Moreover, the measuring method of the bulk density of coal after coal or a bulk density improvement agent addition is as follows.
[Bulk density measurement method]
After 500 g of coal is uniformly and uniformly dropped from the upper end of a cylindrical 1 L graduated cylinder (made of glass), the graduated cylinder is naturally dropped once from a height of 1 cm, and the volume after dropping is measured. The bulk density was calculated from the volume and weight (500 g).
The bulk density improvement rate was calculated by the following formula.

  In addition, as a mixer for mixing the bulk density improver with coal, a drum mixer (60 rpm) having a diameter of 30 cm and a depth of 15 cm was used in order to simulate mixing in a belt conveyor connecting part or a crusher in an actual machine. .

[Examples 1 to 3, Comparative Examples 1 and 2: Examples and Comparative Examples showing the influence on the effect of improving the bulk density of -3 mm particles of coal]
The test coal was sieved from the coal pulverized with a juicer mixer, and the particle size was adjusted so that the -3 mm particle size would be 50%, 70%, 75%, 80%, and 85%.
On each -3 mm grain coal, chemical | medical agent a was added with the dropper so that it might become 0.05 weight% as an addition amount of an active ingredient with respect to coal, and it stirred for 30 seconds with the drum mixer.
Table 1 shows the bulk density of the coal before and after the addition of the bulk density improver and the bulk density improvement rate.

  From Table 1, when the particle size of the coal becomes finer, the bulk density of the coal itself decreases, but when the bulk density improver is applied to coal pulverized to a -3 mm particle size of 75% or more, the bulk density is improved efficiently. I understand.

[Examples 4 to 5: Examples simulating the case where a bulk density improver is added at point B in FIG. 1]
In order to simulate the state in which the bulk density improver is added to the coal after being pulverized by the pulverizer in the actual machine and this bulk density improver is mixed in the belt conveyor connecting portion, the test coal is first added to the juicer. Using a mixer, pulverization was performed so that the -3 mm particle content was 80%.
To this test charcoal having a particle size of 80%, the chemical a was added with a dropper so as to have an addition amount of point B shown in Table 2 (addition amount of active ingredient to coal), and then mixed for 30 seconds with a drum mixer.
Table 2 shows the bulk density of the coal before and after the addition of the bulk density improver and the bulk density improvement rate.

[Examples 6 to 9: Examples simulating the case where a bulk density improver is added at points A and B in FIG. 1]
In the actual machine, the bulk density improver is added to the coal before being pulverized by the pulverizer, and then the bulk density improver is mixed while being pulverized by the pulverizer. In order to simulate the state in which the density improver is mixed at the belt conveyor connecting portion, first, dropper is added so that the chemical a is added to the test coal at the point A addition amount (active component addition amount relative to coal) shown in Table 2. Then, the mixture was pulverized with a juicer mixer so that the -3 mm particle content was 80%. The coal immediately after pulverization was put into a drum mixer, and the chemical a was added with a dropper so as to have an addition amount of point B shown in Table 2 (addition amount of active ingredient to coal), and then mixed for 30 seconds with a drum mixer.
Table 2 shows the bulk density of the coal after the addition of the bulk density improver and the bulk density improvement rate.

[Comparative example 3: Comparative example simulating the case where a bulk density improver is added at point A in FIG. 1]
In order to simulate the state in which the bulk density improver is added to the coal before being pulverized by the pulverizer in the actual machine and then pulverized by the pulverizer, After adding the drug a to the charcoal with a dropper so that the amount of the active ingredient added to the coal is 0.05% by weight, using a juicer mixer, the -3 mm particle content is crushed to 80%, The coal just after pulverization was mixed with a drum mixer for 30 seconds.
Table 2 shows the bulk density of the coal before and after the addition of the bulk density improver and the bulk density improvement rate.

  Table 2 also shows the results of Example 2.

  From Table 2, it can be seen that the addition of a bulk density improver to the pulverized coal can achieve a high bulk density improvement effect with a small dosage.

[Examples 10 and 11: Examples simulating the case where a bulk density improver is added at points B and C in FIG. 1]
In order to simulate the state in which the bulk density improver is added to the coal after being pulverized by the pulverizer at two locations in the actual machine and the bulk density improver is mixed at the belt conveyor connecting portion, Use a juicer mixer to grind the test coal so that the -3mm particle size is 80%, and then drop the chemical a into the coal so that it becomes the point B addition amount (active component addition amount to the coal) shown in Table 3 After mixing with a drum mixer for 15 seconds, the stirring was stopped once, and then the drug a was added again with a dropper so as to be the amount of addition of point C shown in Table 3 (the amount of active ingredient added to coal). Mix for 15 seconds with a mixer.
Table 3 shows the bulk density of the coal before and after the addition of the bulk density improver and the bulk density improvement rate.

  In Table 3, the results of Examples 2 and 4 are also shown.

  From Table 3, it can be seen that an even better bulk density improving effect can be obtained by dividingly adding the bulk density improver at two locations after pulverization.

[Examples 12 to 15: Examples showing the influence of the concentration of the bulk density improver on the bulk density improving effect]
In Example 10, the bulk density improving treatment was performed in the same manner except that the chemicals shown in Table 4 were added as the bulk density improver in the addition amount shown in Table 4, and the results are shown in Table 4.

  From Table 4, there is a preferred range for the concentration of the bulk density improver, and the bulk density improvement rate is high at 7.5, 10 and 15% by weight, and particularly the good improvement rate is shown at 10% by weight. I understand.

It is a schematic diagram which shows the structural example of a coal transport line. It is a schematic diagram which shows the other structural example of a coal transport line.

Explanation of symbols

1 Mixing tank 2 Pulverizer 3 Coke oven 4 Humidity control equipment T Transfer section

Claims (3)

In the method of improving the bulk density of coal by adding a surfactant to the coal being transported in the coal transport line charged in the coke oven,
The transport line is configured to transport coal to a coke oven through a pulverizer and a humidity control facility provided at a subsequent stage,
The surfactant is added to the coal pulverized so that the particle size of 3 mm or less is 75% or more by the pulverizer on the upstream side of the humidity control coal equipment. A method for improving the bulk density of coal for coke production. Characterized in claim 1, the upstream side or downstream side of said timing wet coal facilities, by further adding a surfactant, adding the surfactant, the two locations transport lines of pulverized coal A method for improving the bulk density of coal for producing coke. According to claim 1 or 2, wherein the surfactant is co characterized in that an active ingredient concentration of 5 to 15% by weight aqueous solution - bulk density method for improving coal for box production.

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