JPS6051781A - Production of coke for metallurgy - Google Patents

Abstract

PURPOSE:To obtain coke for metallurgy with improved productivity, which has excellent strength, by briquetting blended coal to give a specified cake density and dry-distilling the briquette. CONSTITUTION:In dry-distilling blended coal having appropriate average rank of coalification and appropriate max. fluidity, said blended coal is briquetted to give a cake density of 0.90-1.05. By compacting the blended coal, an increase in the quantity of the coal to be fed into a coke oven by 20-40% can be achieved, as compared with conventional methods. Thus, even when the dry distillation time is prolonged thereby, productivity can be improved. Particularly, with regard to productivity, an operation of a higher oven wall temp. becomes possible by compacting. For example, when the bulk density is 0.75T/m<3> and the oven wall temp. is 950 deg.C in a convention method, DI15<30> is 91.1, while when the bulk density is 1.00T/m<3> in the present invention, DI15<30> can be increased to 93.6 at the same oven wall temp. of 950 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing metallurgical coke, and is intended to provide a method for producing metallurgical coke that has excellent strength and can improve productivity. Metallurgical coke used in blast furnace operations not only serves as a heat source to maintain stable operations, but also as a reducing agent and as an air permeability maintenance material. Its role as a material is important. However, properties required of coke as an air permeability maintenance material include cold strength, CO, post-reaction strength, and hot strength, but among these, coke is considered the most important. The typical property value is cold strength, and the factors that control this coke cold strength include the coking coal properties such as the degree of coalification, softening and melting properties, and the amount of active groups and inert groups on the coal blend side. , carbonization conditions such as bulk density on the coke oven side, flue temperature, and standing time. By the way, the coke strength governing factors in the conventional coke oven as described above are determined by the operating rate derived from the coke balance at that time, etc., so it is important to actively manipulate the typical drum strength as the coke strength. Rather, it is considered that the quality of coke in each black should be stabilized by keeping the above-mentioned factors constant and making the carbonization conditions the same. In other words, the typical blending theory in such conventional methods is to classify coal according to its degree of coalification and fluidity, and determine the drum strength based on the mutual relationship between the two. A chart such as M, O, F based on the ratio and Giessler maximum fluidity was announced, and each coking coal was plotted on the chart, and the incoming coking coal that should be blended was shown on the chart.
The objective is to obtain the required drum strength by determining the composition in consideration of the position of the -IV quadrant. This method not only appropriately manages the coking coal to obtain desirable and stable coke, but it also focuses on blended coal, and also involves methods that can actively improve coke strength etc. on the coke oven side. To date, no preferred technology has been established, although it is of great importance to do so.

The present invention was devised after repeated studies in view of the above-mentioned circumstances, and the present invention is based on the following method: when carbonizing a coal blend with an appropriately selected average degree of coalification and maximum fluidity, the blended coal is press-molded. It is proposed that the cake density be set to 0.90 to 1.05. That is, to further explain the present invention, in order to obtain the necessary strength in such coke, it is necessary to make the average degree of carbonization and the maximum fluidity higher than predetermined values, and the average degree of carbonization is 1.10% or less. It is difficult to obtain a specified coke strength even when the fluidity is quite high in coal blends such as coal blends, and if the fluidity is less than 200 ddpm, even if the average degree of carbonization is high, the DI It is difficult to obtain a preferable coke strength such as 0=92 or higher. However, if the density of the raw coal blend charged during carbonization of such raw coal is increased, the distance between the raw material particles is shortened and the reaction or fusion bond between the particles is increased. As a result, the strength of the substrate can be improved as a result of making it easier and smoother.For this reason, certain equipment or methods have been proposed for the consolidation treatment of such charged coking coal, but it is difficult to simply densify it. However, the details of the coking treatment of the densified coal blend have not been clarified.The present inventors have therefore attempted to solve the problem in such a case. As a result of repeated studies on the relationship between this and the coking process, we found that the density of the coal blend to be charged was changed to the case of ordinary charging (0.7
5T/-) higher than 0.8T/-~Q, 9T/
rr? Although the strength of the coke obtained can be considerably improved by disturbing the bulk density, o, c
Exceeding ++7m'1. OT/n? It was learned that if the density of the coke exceeds 1, the strength of the coke actually decreases. Therefore, as an example, in the above MOF diagram where 3+mn or less is 80 cm and the moisture content is 9 cm, the raw coal blend that is set as the preferred coal blend region has a DI30 of 91.6 in the case of normal operation with a density of 0.75 T/m'. So, this blended coal was consolidated 11 times to produce 1.0T/rr? If it is before or after, the drum index value can be improved to 948 degrees. However, regarding this kind of blended coal, 1. The coke strength when the density is increased to OT/- or higher is as shown in Figure 1, and when the coke strength gradually decreases and approaches 1.1 T/-, DI:
: is about 93. In addition, the coke reaction wave intensity (cok
e strength after action:
The same applies to 1. (hereinafter referred to as C8R). OT 7m
As shown in Fig. 2, a decreasing tendency is observed when the C3R value is 1 or more, and the C3R value reached 50 at around 1.0 T/m', but the C3R value reached 50 at 1.07 to 1.08 T/rr? Then it becomes 35 to 40, and in some cases even less than 30.

Even though coke should be made to have even higher strength when sufficient densification is achieved in this way,
Although it is difficult to fully elucidate the details of the reason for the decline, it is believed that in the case of high density as described above, cracks occur in the structure due to the gas generated during coking. Estimated and factual 1.05T
/i over 1.1T/rr? As shown in Fig. 1.2, the above-mentioned decrease in coke strength becomes more significant as the temperature approaches . 2. By increasing the density within an appropriate range as described above, a sufficient degree of freedom can be obtained regarding the maximum fluidity and average degree of coalification of the coal blend. That is, this relationship is summarized in FIG. 3, and in the prior art, the drum strength DI
In order to obtain D:=92, it is necessary to have an average reflectance Rτ=1.14 or more regarding the degree of coalification, and the maximum fluidity (MF
) is also essential to be 200 or more, and R
τ=0.90, above for MF200 or less)) 1:
Even if : is 82 to 84 and Ro=1.10, DI : is about 87 to 88, and it is clear that it is difficult to obtain the desired drum strength of around I-92 or higher. In contrast, according to the present invention, 1. In the case of OT/m' compacted drum, even when Ro=0.90 and MF=1oo, the drum strength improves to about 88.5, and the same R
Conventional drum strength according to o value and MF value 82)
This shows a significant improvement compared to the MF value of 500.
In the above case, it is clear that p 1:: -g 2 or more will be obtained. Also, Re is 1.0
If 0 or more is consolidated to 1.0T/m' or more, as long as the MF value is 100 or more, it is possible to make p I: 92 or more, and in any case, the degree of coalification (R
It is clear that the desired drum strength can be appropriately obtained without the need for careful selection of coal blends based on o) or maximum fluidity (MF).

In carrying out the present invention, it is of course effective to appropriately refine the grain size of the coal blend, but even if the degree of refinement is not sufficient, an appropriate improvement in drum strength can be achieved. In other words, this relationship is as shown in Figure 4, and in the conventional method, in order to make DI: C, 92 or more, at least the blended coal particle size -3 questions must be 80%.
It is essential that the water content be above 70%, and moisture content should also be taken into consideration. However, in the case of the present invention, even if the 13cm is 70%, it is 93.5 or more, and when it does not reach 70cm, In particular, as the chi value of this -3ram increases, the increase in coke strength is more remarkable than that of the non-consolidated pace, and at -3ram 90chi, D
I can even get values close to 95, and generally 13 miles is 80.
It is advantageous to make it greater than or equal to H.

Of course, as mentioned above, by compacting the coal blend, the amount charged to the coke oven can be increased, that is, the amount charged can be increased by about 20 to 40% compared to the conventional method. It is clear that productivity can be appropriately improved even if the time is increased to a certain extent. In particular, regarding this productivity, it is possible to operate a chestnut with a high furnace wall temperature by compaction as in the present invention, for example, the bulk density is 0.75T/-
D when the furnace wall temperature is 950°C in the case of the conventional method of
I B O is 1!1 91.1, whereas the bulk density is i, oo'r/lr+
In the case of the present invention, if the furnace wall temperature is also 950°C, G: can be improved to 93.6, and this furnace wall temperature can be increased to 1000°C.
℃, even if raised to 1050℃, DI: : is 93 or 928
It is clear that the coke strength is preferable to a certain extent, and if the furnace temperature is raised in this way, the coking treatment time can be shortened and productivity can be sufficiently improved.

In the specific implementation of the method of the present invention, compaction using a stamp bar, compaction using a roll press, a traverse method when using a pressure plate, etc. can be appropriately employed. The width of the consolidated cake can be selected as appropriate for the width of the furnace, but the distance between the furnace wall surface and the cake surface should be as small as it does not interfere with charging the consolidated cake into the furnace. Generally, it is appropriate to set it within the range of 10 to 200% (20 to 40% on both sides).

Specific examples according to the present invention will be described below.

A blended coal consisting of 15I8 patterns with a maximum fluidity MF of 200 ddm and a degree of coalification (vitrinite average reflectance: Rτ) of 1.10, a moisture content of 9%, and a -3 ratio of 80 was processed using the breath traverse method to create a width of 375II+II+ and the height is 9
Bulk density 1.0'l' with 00 tan and length 900 mm
This cake was charged into a coke oven having a wall width of 410 mm, and subjected to carbonization treatment at a wall temperature of 950°C.

That is, for the coke obtained by such treatment, D I
The result of measuring 30 is 93.6, which is the base strength Dx::=91.
It was confirmed that the coke strength was sufficiently improved compared to that of No. x.

The bulk density of the above coal blend is 0.99 T/n?
Under all other conditions, a coke strength of DID = 94 was obtained under the same conditions as above, which is the highest coke strength, and on the other hand, a bulk density of 1.07 T/
n? The bound version had a DI number of 93.2.

Also, when the bulk density is 1.0 Tld, the furnace wall temperature is 1000
DID when carbonized at ℃ is 93.1 and 105
In the case of 0° C., the strength was 92.9, and even though a decrease in strength was observed as the furnace temperature increased, it was still considerably higher than the above-mentioned base strength (91,1).

As explained above, the strength of the coke obtained by compacting the blended coal for producing coke of Tokihato seed coke according to the present invention to a specific range of 0.90 to 1.05 T/ly/ and carbonizing it is effectively improved. Therefore, it is possible to appropriately expand the range of selection based on the maximum fluidity and coalification degree of such blended coal, to obtain coke with a specified strength, and to provide a product with a specified quality at a low cost. It is, after all, an invention with great effects.

[Brief explanation of drawings]

The drawings show the technical contents of the present invention, and Fig. 1 is a diagram summarizing the relationship between the compaction density of the coal blend and the coke strength D1 obtained by carbonization treatment. Figure 2 is a chart showing the relationship between the compaction density of the coal blend and the strength after coke reaction, and Figure 3 shows the normal base and 1. OT/l
Figure 4 shows the relationship between the fluidity of the blended coal and the drum strength by comparing the coal blends consolidated to tl. O
This is a diagram summarizing T/- according to the method of the present invention. Patent Applicant: Nippon Kokan Co., Ltd. Inventor: Ken Nemoto - Takashi Shibuya, Tomo Kato, Norito Kato, Takeshi Fujimura, Yoshio Sano, Fudo Hiroshi Saito ■ ■ ■ ■ Kai+Koshi Izumi+, li -(MF) -3rn melon 2

Claims (1)

[Claims] 1. When carbonizing a blended coal whose average degree of coalification and maximum fluidity are appropriately selected, the blended coal is pressurized to a cake density of 0.90 to 1.05. A method for producing metallurgical coke, characterized by: 2. A method for producing metallurgical coke according to claim 1, using a coal blend whose hardness is less than 3 and more than 80.