JP2937604B2 - Treatment method for coke-mixed coal dust - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for collecting dust collected in a coke plant and containing coke and coal and treating the collected dust in a coke oven.

[0002]

2. Description of the Related Art In recent years, measures against dust and water pollution have been taken at steelworks in order to strengthen environmental measures. For example,
At coke factories, environmental measures are concentrated in particular. Aggressive equipment measures such as thickener equipment are being implemented.

With the improvement of these measures, a large amount of coke-mixed coal dust containing a mixture of coke powder collected by dust collection and various types of coal powder of unknown brand has been generated. In addition, these dusts are collected by sedimentation with a thickener, and have a water content of about 20%. Since they are unknown coal and contain coke, they can be reused as raw materials for coke ovens. Is difficult to mix, several percent
At present, only mixed insertion can be performed.

In general, as a method of treating and utilizing coal contained in wastes, for example, Japanese Unexamined Patent Publication (Kokai) No. 58-109127 discloses a method in which water and a binder are added to coal ash collected by dust collection, followed by stirring and granulation. Japanese Unexamined Patent Publication (Kokai) No. 58-5394 discloses a method for recovering unburned coal and a method for recovering coal by using granulated coal obtained by underwater granulation of pulverized coal and a binder in a boiler or the like. As a method,
No. 09291 discloses a method of mixing and aggregating coal particles and a hydrocarbon binder to mechanically dehydrate them.

[0005]

The method disclosed in the above-mentioned conventional method is directed to coal containing one or a plurality of brands, and is a mixture of coal powder and coke powder having different particle characteristics. Granulation cannot be achieved even if the powder is agitated and mixed based on the prior art.

The present invention pays attention to the difference in lipophilicity between coke and coal when a coal slurry and an oil are mixed and stirred to recover the coal, and the tar generated from the coal is regarded as an oil, and the coal-based coal is used as the oil. By controlling the viscosity of the oil component having high adhesion, the lipophilicity of coke particles, which is less lipophilic to coal particles, is improved, and granulation can be performed.

[0007]

According to the present invention, there are provided (1) a mixture of coke powder and coal powder collected and collected in a coke production process, a weight ratio of 40 to 60: 60 to 40,
After coke-mixed coal dust having an average particle size of 60μ is converted into a water slurry having a dust collection concentration of 0.5% to 20%, the coke-containing coal water slurry is stirred while adding tar as oil having different viscosities in multiple stages. A method for treating coal dust mixed with coke, characterized by mixing and granulating. (2) A tar having a viscosity of 100 cp or less is added to the coke-containing coal water slurry of the above item (1), and the mixture is stirred and mixed so that the tar adheres to the surface of the solid particles.
The method for treating coal dust mixed with coke according to the above (1), wherein cp tar is added, mixed, stirred and granulated. It is.

[0008]

According to the present invention, first, coke-mixed coal dust powder having a weight ratio of 40 to 60:60 to 40 and an average particle size of 60 .mu. In which coke powder and coal powder collected in the coke production process are mixed. Is a water slurry having a concentration of the dust collection powder of 0.5% to 20%.

When the concentration of dust particles in the above-mentioned coke-containing coal slurry exceeds 20%, not only does a stirring and mixing process require a stirring and mixing device equipped with a powerful drive device, but also a stirring and mixing device.
It becomes difficult to granulate. On the other hand, when the concentration of the dust collection powder of the coke-containing coal water slurry is less than 0.5%, a large amount of water is simply moved and stirred, and the operation cost for granulation becomes enormous, resulting in poor productivity.

As described above, the concentration of the coke-containing coal water slurry is controlled in the range of 0.5% to 20% so that the slurry can be supersaturated with a binder for granulation so as to collide with the binder during stirring.

Since tar is used as the oil component having a different viscosity in the coke-containing coal water slurry having a concentration of 0.5% to 20%, as shown in FIG. Can be secured.

Since tars having different viscosities are stirred and mixed while being added in multiple stages, a low-viscosity tar, that is, an oil having a high dispersibility is first added and mixed with stirring to obtain solid particles, especially coke particles, in the water slurry. The tar adheres to the surface of the powder, the lipophilicity is improved, and the wettability with the oil having the viscosity required during granulation is ensured.

Subsequently, when a high-viscosity tar, that is, an oil having a viscosity required for granulation is added and stirred and mixed, the coke particles are granulated almost in the same manner as the coal particles. In the granulation process by the stirring and mixing, the demineralization of the coal particles also proceeds.

The viscosity of the above tar can be changed by the amount of the light oil component in the tar or by the addition operation, and can be changed by the step of the temperature of the tar. spread. In addition, when tar is used at a specific temperature, it goes without saying that the temperature of the coke-containing coal water slurry is set to that temperature.

The operation of stirring and mixing while adding tar as oil components having different viscosities to the coke-containing coal water slurry in multiple stages is performed in one stirring and mixing device or a plurality of stirring and mixing devices are prepared. Then, the mode in which the viscosity of the oil component is increased to, for example, 2 to 4 stages in order from the upstream stirring and mixing device can be appropriately selected and implemented.

In a specific embodiment of the present invention, tar having a viscosity of 100 cp or less is added to the coke-containing coal water slurry and mixed with stirring to attach the tar to the surface of the solid particles. Tar adheres to the oil and its lipophilicity is improved.

When the viscosity of the tar exceeds 100 cp, the efficiency of adhesion to the surface of the coke particles deteriorates, and the granulation in the subsequent granulation step becomes insufficient. Incidentally, if the viscosity of the tar is too low, it is possible to improve the lipophilicity by sequentially attaching tars having a high viscosity, but since the number of steps is increased, or the heat source to maintain such viscosity becomes enormous,
The lower limit of the tar viscosity is preferably up to 15 cp.

If tar having a viscosity close to 100 cp and a relatively high viscosity range is used in the above-mentioned operation process, granulation of some of the solid particles starts. It does not inhibit.

The coke-containing coal water slurry obtained by adding the above-mentioned tar of 100 cp or less and stirring and mixing the mixture, then has a viscosity of 8%.
0-200 cp tar is added and mixed and stirred.
The coal particles and the coke particles are mixed and granulated, respectively.

When the tar viscosity is less than 80 cp,
Although it improves the lipophilicity of coke, it cannot be granulated, because even coal particles do not have the strength to bond the particles together. On the other hand, if it exceeds 200 cp, the dispersibility of the oil deteriorates, so that the granulation growth varies, which is not preferable.

As described above, since the present invention uses tar, which is an oil component having a different viscosity, the surface characteristics of coke, which is particularly poor in lipophilicity, can be improved in advance, and high coke and coal can be granulated and grown. Agitation granulation can be performed in the tacky state.

In the present invention, the total amount of tar, which is an oil component having a different viscosity, is preferably 150 to 300 l / t. Medium coke amount,
It can be appropriately selected according to the particle size distribution and the form of the stirring granulation equipment.

Further, according to the present invention, the coke powder is coated with a highly dispersible oil component to granulate the pulverized coal around the coke powder. The dewatering of the granular coal is substantially effected.

Further, according to the present invention, the granulated coal subjected to the above-mentioned deashed granulation is blended into the coke raw coal for blast furnace and dry-distilled, so that the deashed granulated coal makes the inner particles more closely contact with oil. It is possible to obtain coke for blast furnace having strong strength by improving mutual melting property.

Further, since coke is already contained, coke for a blast furnace which can also prevent cracks in the shrinkage process during carbonization and contribute to an increase in the particle size of product coke can be obtained.

Hereinafter, the present invention will be specifically described with reference to the drawings. FIG. 2 shows an example of a processing facility for carrying out the present invention.

The coke and coal powder generated in the coke factory are collected by the bag filter 1 and fixedly cut out.
The coal is cut out into a slurry tank 3 and the water pipe 4 is adjusted to a slurry having a carbon content of 0.5 to 15%.

The temperature of the water used at this time is adjusted to the temperature required for the stirring tank 7 in the next step.

The slurry whose concentration has been adjusted is supplied to the stirring tank 7 by the slurry pump 5. The supplied slurry and tar whose viscosity has been adjusted to 100 cp or less are supplied from a tar tank 11 by a tar pump 9, mixed by a stirrer 8, and adhered to the surface of the solid particles. The rotation speed of the stirrer 8 is desirably such that the slurry does not settle and separate. In order to maintain the dispersibility of the tar at the time of stirring, the stirring tank 7 is kept warm with steam 6 so as to have a constant water temperature.

The mixed slurry is supplied to a slurry pump 10
To the granulator 17. At the same time, viscosity 80-200
The tar adjusted to cp is supplied from the tar tank 12 to the granulator 17 by the tar pump 13 and mixed and agitated to granulate the coal.

The granulated product is supplied to a dehydrator 15 to separate water and granulated product, and the dewatered granulated coal is transported to a facility such as a coke oven by a belt conveyor 16. The separated water is guided to a wastewater treatment facility (not shown) such as a thickener to be treated.

[0032]

EXAMPLE A dust collection powder having an average particle size of 62μ mixed with coke 48% and coal 52% by weight is mixed in a slurry tank with hot water to a concentration of 15% and a water temperature of 70 ° C. Is supplied to the stirring tank, and the tar tank is set at 70 cp so that the viscosity of the tar becomes 50 cp as shown in FIG.
At 150 ° C., 150 l of tar per ton of coal are supplied to the stirring tank, and the peripheral speed of the stirrer is 5 m / s and the residence time is 1
The mixture was stirred and mixed under the condition of 0 minutes.

At this time, the steam was kept warm so that the temperature in the tank became 70 degrees. This mixed and stirred slurry and tar having a viscosity of 200 cp were introduced into a horizontal granulator at a rate of 150 l per ton of coal, and stirred and granulated under the conditions of a stirring blade peripheral speed of 5 m / s and a residence time of 10 minutes.

FIG. 4 shows the result of the granulation. 0.5m
The recovery rate of granulated coal of m or more is hardly recovered by simply mixing it with the conventional 200 cp without tar viscosity adjustment, whereas this method makes it possible to recover more than 90% of coal. Reuse is now possible.

[Brief description of the drawings]

FIG. 1 is a graph showing wetting properties of coal and coke for each tar viscosity.

FIG. 2 is an explanatory diagram of a processing facility according to an embodiment of the present invention.

FIG. 3 is a graph showing the relationship between tar temperature and viscosity.

FIG. 4 is a graph showing the relationship between the recovery rate of granulated coal between the method of the present invention and the conventional method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Bag filter 2 ... Cut-out valve 3 ... Slurry tank 4 ... Water pipe 5 ... Slurry pump 6 ... Steam pipe 7 ... Stirring tank 8 ... Stirrer 9 ... Tar pump 10 ... Slurry pump 11, 12 ... Tar tank 13 ... Tar Pump 14: Granulator 15: Dehydrator 16: Conveyor

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takayoshi Ikeda 5-3 Tokai-cho, Tokai-shi Nippon Steel Corporation Nagoya Works (56) References JP-A-60-186595 (JP, A) JP-A-60-208391 (JP, A) JP-A-58-136697 (JP, A) JP-A-58-113296 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C10L 5 / 00-10/00

Claims (2)

(57) [Claims] 1. A weight ratio of 40 to 60:60 in which coke powder and coal powder collected in a coke production process are mixed.
~ 40, coke-mixed coal dust powder with an average particle size of 60μ,
After forming a water slurry having a concentration of the dust collection powder of 0.5% to 20%,
A method for treating coke-mixed coal dust powder, wherein the coke-containing coal water slurry is stirred and mixed while adding tars as oils having different viscosities in multiple stages and granulated. 2. A coke-containing coal water slurry having a viscosity of 10
2. A coke according to claim 1, wherein tar of 0 cp or less is added and stirred and mixed to attach the tar to the surface of the solid particles, and then tar with a viscosity of 80 to 200 cp is added and mixed and agitated to granulate. Processing method for mixed coal dust.