JP3639075B2 - Method for controlling coke breaking powder for metallurgy - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for controlling the particle size and amount of powder generated from coke by impact received after the production of coke .
[0002]
[Prior art]
Since the properties of blast furnace coke directly affect the operation of the blast furnace, the greatest attention is paid to ensure the prescribed properties.
[0003]
One of the coke quality control indicators related to blast furnace operation is the coke cold strength index. There is. Each of these indices is the initial input sample of the sample weight on the sieve (or under the sieve) of the prescribed size among the coke taken out after putting the prescribed amount of coke into the cylindrical container and rotating the container a specified number of times. Expressed as a percentage of weight.
[0004]
As one of the means to control these management indexes, a method of adjusting the pulverized particle size of the raw coal to a constant value for the purpose of homogenizing the raw material is widely used. A method of improving coke strength by finely pulverizing and uniformly dispersing charcoal and high inert (inactive component) charcoal is generally practiced. A representative method is the SOVACO method. This method utilizes the difference in pulverization between coal structures, and first prevents the excessive grinding of vitrit containing a large amount of active ingredients, which are easily pulverized, and at the same time pulverizes the vitrit portion in order to pulverize the inactive components. After separating by sieving, the dort portion rich in inert components that are difficult to pulverize is pulverized by repeating pulverization and sieving several times, and then both are mixed. The above-mentioned coke strength index is intended to be improved.
[0005]
In addition to the method for homogenizing the raw materials, a method for improving the coke strength by increasing the packing density of the charged coal has been widely practiced. Specific methods for improving the charging density of the charging coal include a method of adjusting the particle size distribution of the charging coal, a method of adjusting the moisture of the charging coal, and a method using a certain filling pressure. Among these methods, the method for adjusting the particle size distribution of the charged coal can simultaneously homogenize the raw material by appropriately selecting the raw material coal to be pulverized, and such a method is also generalized. Yes.
[0006]
[Problems to be solved by the invention]
A method for adjusting the pulverization particle size of raw coal has been conventionally performed, and selective pulverization combined with pulverization and sieving as in the SOVACO method has also been performed, but all of these methods have the above-mentioned coke strength index. The purpose is to improve.
[0007]
On the other hand, all the above-mentioned coke strength indexes are used as the evaluation index of coke strength by the total weight of coke (coke powder) having a particle size of a specified sieve opening or less generated when a certain impact is applied, At that time, if the particle size is equal to or less than the specified sieve opening, the coke is treated as coke powder regardless of the particle size.
[0008]
By the way, it is known that not only the total amount but also the particle size of the powder generated during the transport of coke, during charging into the blast furnace or when descending the blast furnace has a great influence on the blast furnace condition. .
[0009]
However, so far, no effective method for controlling the particle size of coke powder has been found, and the above-mentioned coke strength is also the total weight of coke (coke powder) having a particle size smaller than the specified sieve opening. Remains an evaluation index for coke strength.
[0010]
If it becomes possible to control the particle size and amount of coke breaking powder before coke production, the porosity of the coke packed bed in the blast furnace will be reduced, resulting in poor air permeability or even a reaction in the blast furnace. It is possible to reduce the amount of coarse powder that reaches the lower part of the furnace without being consumed and accumulates in the core, and on the other hand, it is also possible to reduce the amount of fine powder that is generated by impact and contaminates the environment. Furthermore , if the fracture behavior of coke can be predicted in this way, the coke strength index can be controlled.
[0011]
Under such a background, the present invention focuses on an index when a specific coal type portion of the blended coal is pulverized, and has a specific correlation with respect to the powder generated from coke obtained from the blended coal. The object is to provide a method for controlling the particle size and amount of the powder generated from coke by finding out .
[0012]
[Means for Solving the Problems]
The control method of the metallurgical coke breaking powder of the present invention,
The amount of pulverized product in a specific particle size range b when the target coal part is pulverized with respect to a blended coal containing a low-coalization degree and / or high inert coal type (hereinafter referred to as the target coal part) at a specific ratio a And the amount y of the coke powder having a specific particle size range c generated by the impact received after the production of the coke produced from the blended coal is determined based on the test data or the operation data in advance. Understand conditions a, b, and c indicating correlation,
Accordingly, when producing coke from blended coal, the particle size and amount of the powder generated from coke based on the strong xy correlation grasped above and the conditions a, b, and c for obtaining such a correlation. it is characterized in <br/> it has to be controlled.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below. In this specification, “inert” means “inactive ingredient”.
[0014]
If the flow from raw coal to coke consumption is conceptually shown, it will be "raw coal → pulverization → charging into coke oven → dry distillation → coke transportation / transport → coke consumption". Coke breaking powder is generated by various impacts in the process of transporting and transporting coke and consuming coke.
[0015]
In the present invention, attention is focused on the coal type (target coal portion) of the low coalification degree and / or high inert among the blended coals.
[0016]
Next, for the blended coal containing the target coal at the specific ratio a, the amount x of the pulverized product in the specific particle size range b when the target coal portion is pulverized and the impact received after the production of coke produced from the blended coal An amount y of coke powder having a specific particle size range c to be generated is obtained in advance based on test data or operation data.
[0017]
Milling of the target coal portion, for example, to select a grinder, or adjust the operating conditions of the grinding apparatus such as a rotating speed adjustment and load regulation of the crusher, combination with selected grinding method and a grinding and sieving And so on.
[0018]
After determining the amount x of the pulverized product in the specific particle size range b and the amount y of the coke powder in the specific particle size range c, the conditions a, b, c.
[0019]
And when manufacturing coke from blended coal, based on the strong xy correlation grasped | ascertained above and the conditions a, b, and c from which such correlation is obtained, the particle size and quantity of the powder generated from coke To control.
[0020]
As described above, a specific method for obtaining the conditions a, b, c and the xy correlation, and finding the grasp of the conditions a, b, c showing the strong xy correlation from the conditions a, b, c will be described below. An example will make it clear.
[0021]
【Example】
Hereinafter, the present invention will be further described with reference to examples.
[0022]
Example Coal was produced in a test furnace after pulverizing and adjusting a coal type portion (target coal portion) described later in the blended coal using blended coal in actual operation.
[0023]
That is, using each of the coke samples manufactured in the test furnace, assuming the “impact received by the coke”, a destructive test (150 rotations) was performed by applying the drum method of the rotational strength test method of JIS K2151. The particle size distribution of under 15mm sieve as generating powder coke after addition of impact on coke this way, together with the sieved by several sieves of different mesh size sieve to measure the weight of each particle size Was determined by A result is demonstrated based on FIGS.
[0024]
FIG. 1 is intended for a blending ratio of a = 33% with five types of plain coal (target coal portion) selected from among coal blends selected from the low coalification side and those with a large amount of inerts. the milled particle size (target coal partial particle size) (b = 3 mm undersize wt%) of the time, examined for simple correlation between weight in each particle size fraction of occurrence coke powder after impact test, single for each granularity of generating coke powder The correlation coefficient is shown. The horizontal axis represents the particle size (mm) of the generated coke powder after the impact test, and the vertical axis represents the single correlation coefficient between the target coal partial particle size and the amount of coke generated powder for each fraction.
[0025]
From Figure 1, a coke powder of particle diameter of about 1.5Mm～15mm, the relationship between the target coal portion granularity, it can be seen that a strong negative correlation is observed.
[0026]
FIG. 2 is a plot of the relationship between the amount of generated powder y and the target coal partial particle size, as an example, in which the coke powder under a 15 mm sieve is divided into upper and lower parts of a 3 mm sieve in the result of FIG. The horizontal axis is the amount x of the target coal partial particle size ( b = 3 mm under sieve weight%) , and the vertical axis is the amount of coke powder generation y (g / 10 kg) after the impact test.
[0027]
From FIG. 2, there is a strong correlation between the target coal partial particle size ( b = 3 mm under sieve weight%) and the amount of powder generation y for the coke coarse particle portion ( particle size range c = 3 to 15 mm) after the impact test. It can be seen that
[0028]
On the other hand, from FIG. 2, between the target coal partial particle size (b = 3 mm under sieve weight%) and the amount of powder generation y for the coke fine particle portion (particle size range c = less than 3 mm ) after the impact test , There is no clear correlation.
[0029]
From the above results, by adjusting the pulverization according to the low coalization degree and / or the amount of high inert coal type in the blended coal, It can be seen that control is possible .
[0030]
【The invention's effect】
According to the present invention, it is possible to control the particle size and the amount of generated powder of broken powder generated by various impacts received after coke production. Therefore, the present invention is highly useful in the following points.
[0031]
When using the coke after production, the amount of dust generated during transportation and transfer is related to the amount of fine powder, so it is environmentally significant to control the amount of fine powder generated by impact.
[0032]
Ensuring air permeability of the packed bed with iron ore, pellets, coke, etc. in the blast furnace is regarded as important. Coarse powder that reaches the lower part of the furnace without disappearing in the upper part of the furnace due to the reaction in the blast furnace lowers the porosity of the packed bed and lowers the air permeability. Therefore, it is meaningful in blast furnace operation to control the relatively coarse generated powder among the broken powder due to the impact of coke.
[0033]
Furthermore, since the coke strength index can be controlled by controlling the amount of fine powder and coarse powder generated, it is also significant in the production of metallurgical coke.
[0034]
In addition, since the pulverization particle size adjustment of the low coalification degree and / or high inert coal type in the blended coal can be easily performed , handling in operation management is easy.
[Brief description of the drawings]
FIG. 1 is a graph showing a relationship between a particle size (mm) of coke powder generated after an impact test and a single correlation coefficient between target coal partial particle sizes.
FIG. 2 is a graph showing the relationship between the target coal partial particle size (3 mm under sieve weight%) and the amount of coke powder generated (g / 10 kg) after the impact test.

Claims (1)

The amount of pulverized product in a specific particle size range b when the target coal part is pulverized with respect to a blended coal containing a low-coalization degree and / or high inert coal type (hereinafter referred to as the target coal part) at a specific ratio a And the amount y of the coke powder having a specific particle size range c generated by the impact received after the production of the coke produced from the blended coal is determined based on the test data or the operation data in advance. Understand conditions a, b, and c indicating correlation,
Accordingly, when producing coke from blended coal, the particle size and amount of the powder generated from coke based on the strong xy correlation grasped above and the conditions a, b, and c for obtaining such a correlation. A method for controlling coke-breaking powder for metallurgy, characterized in that it is controlled.

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