JPS5936188A - Method for improving bulk density of charging coal into coke oven by briquetting treatment - Google Patents

Abstract

PURPOSE:To improve the bulk density of coal and reduce the variation in the bulk density distribution in a coke oven, by briquetting a coal for charging into the coke oven under specific conditions to keep a specific particle diameter distribution, and charging the resultant coal into the coke oven. CONSTITUTION:A mixed coal obtained by treating a coal for charging into a coke oven in a pulverizer or coal mixer, used in the treating process is without heating and kneading treatment briquetted in a compression briquetting machine at ordinary temperature to give a briquetted coal having such a retained particle size distribution as to give >=20pts.wt. weight ratio particles having >=6mm. particle diameter, which is then wholly charged through a usual coal feeding path into the coke oven. Thus, the average bulk density of the charged coal in the coke oven is improved, and the variation in the bulk density distribution in the coke oven is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a technology for improving the bulk density of coke oven charged coal and reducing variations in bulk density distribution within the coke oven through pretreatment of coke oven charged coal in the production of metallurgical coke. It is related to.

In order to produce high-strength metallurgical coke or to improve coke productivity, it is essential to increase the bulk density of coal charged in a coke oven. Conventionally, there are two methods for improving the bulk density of charged coal by charging blended pulverized coal into colloids into a coke oven using a molding machine or the like. The method is the so-called molded interleg method (referred to as the A method). This method is
After pulverizing a portion of the blended coal, the caking agent and the blended coal are uniformly mixed using a heating mixer and formed into briquettes using a double roll molding machine. The molded briquettes are passed through a sieve to maintain almost the original shape of the briquettes, then mixed with 30 to 40 parts by weight of powdered coal blend and charged into a mixing furnace. The sieved briquettes are sorted in the process, and the collapsed briquettes are crushed again and returned to the kneading and molding process. This method has the following drawbacks.

(1) The equipment configuration is complicated. In other words, a pulverizer for molding raw materials, storage, heating and supply equipment for binder, heating kneading machine, waste water treatment equipment, briquette sieve, briquette storage equipment, transportation and re-grinding equipment for disintegrated briquettes, briquette cooling equipment, Equipment for uniformly mixing briquettes and powdered coal blend is required. Therefore, applying this method to current coke production equipment requires a large capital investment.

(2) Requires a binder. That is, 5 to 8 parts by weight of a petroleum-based or coal-based binder is required based on the briquette raw material. Furthermore, in order to produce strong briquettes, the caking agent and powdered coal must be kneaded while being heated.

Therefore, the price of the binder, the cost of heating, etc. affect the manufacturing cost.

(3) Briquettes and powdered coal tend to separate and segregate during charging into a coke oven. Therefore, variations occur in the bulk density distribution of the charge in the coke oven.

Another conventional method (referred to as method B) is a method using blended coal without using a binder. This method uses briquettes formed without subjecting the coal blend to heating and kneading treatment, and, like method A, the briquettes are charged into a coke oven while minimizing disintegration of the briquettes.

The disadvantage of this method is that the briquettes are prone to disintegration because no binder is used, so care must be taken to install a double roll forming machine above the coke oven and to shorten the conveyance distance of the briquettes. It is in. Therefore, it was difficult to apply Method B to current coke ovens.

The present inventors have conducted extensive research in order to apply briquettes that do not use a binder to current coke ovens.

The purpose of the method of the present invention is to eliminate the drawbacks of the conventional agglomeration treatment as described above, improve the bulk density of coal charged in a coke oven, and reduce the variation in bulk density distribution of coal charged in a coke oven. The present invention provides a method for improving the bulk density of coal charged in a coke oven by chemical treatment.

The method of the present invention is characterized in that the particle size distribution range of the agglomerated coal is such that the proportion of heavy electric current having a particle size of 6 mm or more immediately before charging into a coke oven is 20 or more stacked parts.

Next, the present invention will be specifically explained.

As mentioned above, in order to improve the productivity of the coke oven, it is preferable to increase the bulk density charged into the coke oven.

In the current coke oven operation, the total particle size is reduced to 25m+n.
Ido, and 3? Raw coal pulverized to about 80 to 88 parts by weight of 1'l++ or less is charged. Conventionally, it has been known that the bulk density of coke oven charging increases when the proportion of fine powder with a particle size of 8 mm or less in charging coal decreases. The inventors
If the proportion of heavy electric currents with a grain size of 3s+a or less in the charging coal is reduced and the proportion of heavy electric currents with a particle size of 6 or more is intentionally increased, the mixed bulk density will significantly increase, and the bulk density distribution in the furnace will change. It was found that the variation was reduced. If we try to achieve this kind of particle size distribution only by controlling the crusher, if we use a blended coal consisting of more than 10 brands of coal, as in the current operation,
Only the easily pulverizable coal in the coal blend is reduced to granules, and the difficult to crush coal remains in large chunks, which impairs the uniformity of the coal blend and lowers the coke strength after drying.

Therefore, the present inventors used a pulverizer according to the current method to reduce the particle size to 3 F or more.
After pulverizing to 80 kg, the blended coal was passed through a coal blender to a uniformly mixed state, and then passed through a double roll molding machine installed on the ground to compress it into agglomerates and attempt to increase the average particle size. (This process is called agglomeration process). Since the blended coal does not go through the kneading process with a binder as in the conventional method, the briquettes after passing through the molding machine easily disintegrate directly under the molding machine.
Appears as an amorphous lump. The degree of disintegration varies depending on the molding conditions, but the average particle size is considerably larger than that of conventional charged pulverized coal. This agglomerated coal will be sent to the coke oven through the current coal feeding system. During this process, the agglomerated coal is subjected to various impacts and its particle size gradually decreases, but the average particle size is still larger and the particle size distribution range is wider than that of currently charged pulverized coal.

As a result, the bulk density when charging into a coke oven becomes significantly higher than that with the current pulverized coal charging method.

Furthermore, in the case of the method of the present invention, variations in the bulk density of charged coal at various parts within the coke oven are reduced. This is because, in the case of the method of the present invention, the particle size distribution range of the agglomeration treatment is widened, and agglomerates of various particle sizes from large particles to small particles are continuously formed. Namely.

When charging a mixture consisting of two components (briquettes and powdered coal) with significantly different particle sizes from a coke oven, such as in the briquette blending method, the component with a large h2 diameter (briquettes) and the component with a small particle size are charged. (pulverized coal) separates and segregates in the furnace, causing variations in the density distribution in the furnace. However, this is because such separation and segregation is less likely to occur in the case of a blend consisting of components of various particle sizes continuously, from large lumps to powder, as in the method of the present invention.

In the method of the present invention, the blended coal pulverized to the same degree as the current coal charging and uncharging from a coke oven is processed at room temperature using a double roll Q-type machine or a piston press, without any pre-treatment such as adding a binder. (7) Pressure M Can be applied to an agglomeration machine. In addition, the agglomeration machine used for the agglomeration treatment can be used in the method of the present invention by agglomerating the powdered coal after passing through the coal mixing machine, so that the average particle size of the charged coal can be increased and the particle size distribution can be widely shifted. However, the present invention is not limited to the double roll molding machine and the like. Any device may be used as long as it can achieve the purpose of the present invention. Moreover, the blended coal after passing through the agglomeration machine does not need to maintain the shape of briquettes.

In fact, when a double roll molding machine is used as an agglomeration machine,
A considerable amount of briquettes collapses directly under the agglomeration machine. However, the powdered coal particles that have undergone compression agglomeration are pressed together to form lumps with large particle sizes, and the average particle size becomes larger and the particle size distribution range becomes wider than that of the powdered coal before the agglomeration treatment. Therefore, the coal blend after the agglomeration treatment does not require sieving and may be directly charged into a coke oven via the current pulverized coal route.

The advantages of the method of the invention are as follows.

(1) The equipment configuration is simple. In the current flame treatment process for coke production, it is only necessary to install an agglomeration machine at any position on the coal feeding route from the coal mixer to the coal tower. therefore,
The method of the invention can be easily applied to current coke production processes. Furthermore, the agglomerated coal used in the method of the present invention does not need to be briquettes with a uniform shape; the point is that it is sufficient to increase the average particle size of the blended coal and widen the particle size distribution range. The agglomeration machine may be of any type as long as it performs this function.

(2) No binder is required.

(8) The charging coal XS degree in the coke oven becomes sieved,
Moreover, the variation in the bulk W5 degree distribution is reduced.

Hereinafter, the present invention will be further explained in detail 1 based on drawings and examples.

In the present invention, as a result of examining the relationship between the bulk density of agglomerated coal with a grain size of 6 or more and the bulk density in the furnace for a large number of agglomerated coals immediately before charging into a coke oven, the results shown in Figure 1 were obtained. Obtained.

In other words, the relationship between the proportion of heavy ML with a particle size of 6 or more in the agglomerated coal (moisture 8 to 9%) and the charging bulk density of the agglomerated coal is distributed within the shaded range in the figure. ! +, S was done. In the current pulverized coal charging method, coal entering the coke oven rg
'M degree is 0.65 torVm8~0.70 ton
/m8. On the other hand, the bulk density in charging bulk density methods other than the method of the present invention (for example, preheated coal charging method, briquette blending method, etc.) is 0.75 tOQ/m' to 0.77 ton/
It has reached m8. Therefore, in order to be able to say that the bulk density of the charged coal was reliably improved by the agglomeration treatment method, it is necessary to
It is considered necessary that the bulk density is 0.75 tons or more. Looking at Figure 1 from this perspective,
Particle size of agglomerated coal at the time of charging rt<t of 6-L or more
It is necessary to make the i ratio 20% or more. In creating FIG. 1, a charged coal bulk density measuring device of the scale shown in Examples described later was used.

Example 1 As a sample coal, about 15 tons of blended coal for normal charging (moisture 90%), which was crushed into a dense part with a total grain size of Q5 mm or more and a grain size of 3 or less, was crushed into a dense portion of 85.4 mm. ” 200 installed double roll forming machine (Ronoshi diameter 520 fin φ, roll 1152 mm, roll top cup size 51 ㎜ x 51
iWX 16), roll rotation speed 16.2 r
l) Ill, linear pressure 4,5 ton, agglomeration processing at 7cm.

The agglomerated coal was sent onto the coke oven through a conventional coal charging system. The agglomerated coal was received in a charging car on top of the coke oven and charged into a bulk density measuring device built next to the coke oven. After charging, the bulk density was measured after leveling the charged coal in the bulk density measuring device through a leveler. In addition, when the method of the present invention is put into actual operation, the agglomerated coal is once charged into a coal tower and then received by a charging vehicle G from section f of the coal tower. For this reason, it is thought that the particle size of the agglomerated coal decreases during the process of passing through the coal tower and being received by the charging vehicle. However, in this test, the agglomerated coal was directly fed from the conveyor into the furnace charging car without going through the coal tower. Therefore, in consideration of the reduction in particle size of the agglomerated coal that would occur when the agglomerated coal passes through a coal tower, the agglomerated coal after passing through the molding machine is lowered in height before being sent to the coke oven. 2
Dropping iron from m to 41° repeatedly 6 times #
I struck. It was then sent onto a coke oven as described above. Table 1 shows the particle size distribution of the agglomerated coal according to the method of the present invention and the powdered coal before the agglomeration treatment (pulverized coal charged by the current powdered coal charging method, that is, the currently charged coal).

As is clear from Table 1, in the case of the method of the present invention, the particle size distribution range is significantly wider and the particle size is larger than that of conventional pulverized coal both directly below the molding machine and in the coke oven L.

Figure 2 shows an outline of the bulk density measuring device used in the test. This device is an iron container with a height of 4 m, a length of 6.7 m, and a width of 400 m, and has two charging holes above the device. As shown in Figure 2, the device has a height of 400°14 (+0.2400.3400°) from the bottom of the device at the midpoint between the two charging ports, directly below the charging port, and midway between the charging port and the end wall. A sampling hole with a diameter of 200 mm is provided at the position, a cylindrical sample collector is inserted into the hole to collect the sample, and the bulk density at each sampling position is evaluated from the relationship between the sample weight and the volume inside the sampler. put out

Figure 3 shows the results of measuring the bulk densities of the agglomerated coal according to the method of the present invention and the relatively soft powdered coal that has not been agglomerated using the current pulverized coal charging method. In the case of the method of the present invention, the bulk density was significantly improved compared to the pulverized coal charging method, and it was shown that the variation in the bulk density distribution was reduced. The average bulk density of the entire bulk density measuring device is determined by the total weight of the charged coal and the device contents f.
Calculated from the relationship of
ry ton/m8, in the case of the method of the present invention (+
, 78 dry ton/m8, and it was confirmed that the method of the present invention exerts a sufficient bulk density improvement effect.

Example 2 Compared to 90 parts by weight of the blended coal of Example 1, slightly caking American coal, which is said to be difficult to make into briquettes using the molding method, was used.
The blended coal containing 0 parts by weight (total particle size of 25 fins or less, and particle size of 3 or less 87.6 fins, moisture 7.0%) was agglomerated using the same agglomeration machine as in Example 1. It was agglomerated under certain conditions. The particle size distribution of the agglomerated coal and the blended pulverized coal that is not agglomerated immediately before being charged into the bulk density measuring device W is as shown in Table 2.

Table 2 Particle size distribution of charged coal with and without agglomeration treatment (w
t%) Bulk density was measured using the same device as in Example 1.

Figure 4 shows the results of bulk density measurements for agglomerated coal and powdered coal that has not been agglomerated. In this example, even though 10 tons of American slightly caking coal, which is said to be unusable in the molded interleg method, was blended into 10 tons, the agglomerated coal having the desired particle size of the present invention was easily produced. Manufactured. Further, the average bulk density and the variation in bulk density distribution were also sufficiently satisfactory as in Example 1.

As described above, the method of the present invention is sufficiently effective in improving the bulk density of charged coal in a coke oven and reducing variations in bulk density distribution in various parts of the oven, and can be applied extremely easily to the current coke manufacturing process. It's a method.

[Brief explanation of the drawing]

Figure 1 shows the proportion (%) of particles with a particle size of 6 or more in the agglomerated coal immediately before charging into a coke oven, and the bulk density of the agglomerated coal (Dr
Figure 2 is a schematic diagram showing the bulk density measuring device used in the examples of the present invention, Figure 8 is a diagram showing the relationship between the method of the present invention according to Example 1 and the current pulverized coal charging method. Figure 4 shows a comparison of the bulk density distribution between
FIG. 2 is a diagram showing a comparison of bulk density distribution between the method of the present invention and the current pulverized coal charging method. Patent applicant: Kawatetsu Chemical Co., Ltd. Patent applicant: Kawasaki Steel Corporation

Claims (1)

[Claims]L: A crusher used in the treatment process of coal charged in a coke oven;
The blended coal that has passed through the coal blending machine is agglomerated by passing it through a compression agglomeration machine at room temperature without any heating and kneading treatment, and the agglomerated coal that has passed through the agglomeration machine is sent through the normal coal feeding route to become coke. When charging the agglomerated coal into the coke oven, the particle size distribution of the agglomerated coal is maintained so that the weight percentage of the agglomerated coal with a particle size of 6 or more is 20 or more times the weight ratio immediately before charging into the coke oven. 8. A method for improving the density of charged coal in a coke oven, which improves the average bulk density of the charged coal in the furnace and reduces variations in the bulk density distribution of the charged coal in the furnace.