JPH0696706B2 - Manufacturing method of coke for refining - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing coke for refining.

More specifically, the present invention relates to a method for producing a refining coke having a large grain size and high quality by controlling the properties and mixing ratio of pitches as a coke raw material for refining.

[Conventional technology]

Generally, the quality of refining coke used in cupola and the like is required to be low in ash content, large in grain size, large in apparent specific gravity, and high in drop strength. Refining coke having such quality has been conventionally produced by dry distillation using an inert carbon material such as coking coal, pitches and petroleum coke, anthracite, and coke fine powder as raw materials.
The role of the pitch is to add a large amount of inert carbon material to the production of coke for refining, to help the cohesive coal and the inert carbon material to bond with each other, and further, the pitch softens and melts. This will increase the filling rate of the charge,
It also has the effect of making dense coke (having a large apparent specific gravity). Thus, although the role of pitches as a raw material blending condition is important from the viewpoint of the quality of coke for refining, systematic studies on the characteristics of pitches on coke quality are rarely found.

Japanese Examined Patent Publication (Kokoku) No. 35453/1985 discloses that high quality casting coke is produced by using pitches having a melting point of about 300 to 400 ° F. The purpose of this gazette is to agglomerate the main raw material petroleum coke and anthracite by carbonization.
It is clarified that the method is different from the conventional coke manufacturing method for foundry using caking coal as a main raw material, and the purpose is different from the present invention.

[Problems to be Solved by the Invention]

The object of the present invention is to obtain coking coal and anthracite, petroleum coke,
By blending pitches with an inert carbon material such as fine coke, and controlling the properties and blending ratio of the pitches to be blended, with respect to the production of refining coke by dry distillation.
It is intended to provide a method for producing a coke having a large grain size, a heavy weight, and a high drop strength (▲ SI ⁴ ₅₀ ▼).

[Means for Solving the Problems]

The present inventors have conducted extensive research in order to solve the above problems. As a result, it was found that even pitches produced using the same coal tar as a raw material, when blended as a coke raw material for refining, a large difference in the quality of the produced coke due to the difference in the properties of the pitches. However, it was found that high quality refining coke can be produced by controlling the properties and mixing ratio of pitches. That is, according to the present invention, the caking coal and the inert carbon substance are mixed with 6 to 20% by weight of pitches containing 15 to 50% by weight of a quinoline insoluble matter (hereinafter referred to as QI), based on the total amount of raw materials. Then, the method is a method for producing a coke for refining, which comprises subjecting the coke to carbonization.

Next, the present invention will be described in more detail.

Raw materials for coking for refining are caking coal, an inert carbon substance, pitches, etc. The pitches have an important role of helping mutual binding between the caking coal and the inert carbon substance. In this case, if the compounding ratio of the pitches is as low as less than 6% by weight, the bond between the coking coal and the inert carbon material becomes insufficient, and the target coke particle size and strength cannot be obtained. On the other hand, if the mixing ratio of pitches exceeds 20% by weight, the drum strength (▲ DI
^{150 15} ▼) can maintain a high level, but the coke grain size and drop strength (▲ SI ⁴ ₅₀ ▼) decrease. As mentioned earlier, pitch softens and melts at a lower temperature than coal in the carbonization process, which increases the density of the charge due to the lubricating action and increases the thermal stress in the carbonization process. It is thought that many cracks occur in the and the particles become finer. In order to clarify the proper mixing ratio of pitches, softening point 90 ℃ ～ 120
℃ coal tar type hard pitch (hereinafter referred to as hard pitch)
As a result of conducting a detailed study using, the hard pitch is equivalent to 6 to 20% by weight in the total raw material blending amount, although it depends on the properties and the blending ratio of the coking coal and the inert carbon substance to which it is applied. It has been found that it is appropriate to mix the above. In this case, more preferably, it is desirable to adjust the blending weight ratio of the inert carbon substance and the pitches within the range of 2.5 to 3.5, but this is preferable because the proper caking property is maintained. It is presumed that this is because the bond between the carbon material and other parts is strengthened and the generation of cracks during the carbonization process is suppressed.

The quinoline insoluble content (QI content) of pitches referred to in the present invention is
In addition to the solid content such as coal fine powder contained in ordinary pitch, it particularly refers to polycondensation carbide having a high molecular weight. These are usually contained in the pitches in an amount of about 5 to 13% by weight.
To adjust this QI content, a concentrated portion containing a large amount of QI content separated by the solvent extraction method when preparing a raw material for needle coke is mixed in the pitch, or a large amount of polycondensed carbide is obtained by heat treatment. There is a method of blending the generated material with the pitch. Furthermore, a detailed study was conducted on the relationship between the properties of hard pitch and the quality of coke, focusing on the QI content in the hard pitch.

In this case, the mixing ratio of the coking coal, the inert carbon substance and the hard pitch was fixed, and only the hard pitch was examined by substituting the same amount with those having different QI contents. As a result, as the QI content of hard pitch increased, the coke grain size increased and the drop strength (▲ SI ⁴ ₅₀ ▼) tended to improve, but the drum strength (▲ DI ¹⁵⁰ ₁₅ ▼) slightly decreased. Turned out to be prone to.

The coke grain size becomes larger and the ▲ SI ⁴ ₅₀ ▼ value improves because the hard pitch coke structure, which is the binder of coking coal and inert carbon material, has a higher flow type when the QI content is low. It is presumed that, while the QI content is increased, a mosaic-like more homogeneous structure is formed, whereas the optically anisotropic structure is formed.

The slight decrease in ▲ DI ¹⁵ ₁₅ ▼ is thought to be due to the decrease in the amount of the cohesive force component due to the increase in QI content during hard pitch. If the QI content in the hard pitch is too low, less than 15% by weight, the coke structure becomes anisotropic and inhomogeneous, and if it exceeds 50% by weight, the caking property is lost. The hard pitch composition ratio must be increased by the shortage, and the QI content is 15 to 50% by weight, more preferably 20 to 40, from the viewpoint of economy and effect.
Weight% was judged to be appropriate.

〔Example〕

Hereinafter, examples of the present invention will be specifically described.
The invention is not limited to this example.

Examples of the present invention are shown in Tables 1 and 2. As shown in Table 1, the raw material has a volatile content of 22.0 to 25.0% by weight.
2 types (A, B) of coking coal, coke fine powder (C), petroleum coke (D) of inert carbon substance and QI content of 8.5 to 3
Hard pitches of four types (E, F, G, H) different from 5.8% by weight were used. Hard pitches F to H have a softening point of 110 ° C and QI
It is obtained by mixing the soft pitch with the QI content obtained by settling and separating the soft pitch with the 8.5% hard pitch. As shown in Table 2, in both the method of the present invention and the comparative method, the compounding ratio of the coking coal and the inert carbon substance was fixed, and QI
Create four combinations of raw material blends in which equal amounts of hard pitches with different contents were replaced, and flue temperature was set in a 1 / 4t test coke oven.
Dry distillation was carried out at 1150 ° C. In the present invention method using a high hardness pitch of QI content, compared to the comparative method using a low hardness pitch of QI content, + 80 mm coke yield is about 7-15 wt%, ▲ SI ⁴
₅₀ ▼ It increased by about 3 to 7 in the index.

Compared with blast furnace coke, the abrasion strength index is higher in the case of refining coke used in cupola, etc. ▲ DI ^{150 15} ▼
It is very important that the grain size of the coke is large and that the drop strength (▲ SI ⁴ ₅₀ ▼) is high. The present invention is the most economical and effective method for ensuring the quality target of refining coke, as will be apparent from the examples.

[Effect of the invention] As described above, in the present invention, among the raw materials of the refining coke, by appropriately adjusting the quinoline insoluble content and the mixing ratio of the hard pitch, the target large particle size, and high quality It is possible to manufacture coke for refining
The effect on industrial economic benefits is extremely large.

Claims (1)

[Claims] Claims: 1. Caking charcoal and inert carbon substances, 6 to 20% by weight of pitches containing 15 to 50% by weight of quinoline-insoluble matter is blended with respect to the total amount of raw materials, and dry-distilled Refining coke manufacturing method.