JPH0689334B2 - Coke manufacturing method - Google Patents

Description

The present invention relates to a method for producing coke, and more particularly to a method for charging dry coal and a method for using an unused carbon substance such as inferior coal and non-caking coal during the production of coke. Is.

[Conventional technology]

Coke for blast furnace is required to have high cold strength and small deterioration of CO ₂ reaction during hot working.

However, high-quality coking coal for producing blast furnace coke is in short supply and is expensive at present and in the future.

For this reason, the coke industry has developed various pretreatment technologies for charging coal, and is trying to produce good quality coke using unused carbon materials such as inferior coking coal or non-caking coal.

As one of these pretreatment techniques, there is a dry coal charging method in which the charged coal is dried and charged into a coke oven.

When this dry coal charging method is applied to charging coal, it is effective not only in saving energy but also in cold strength of coke.

However, it is not always possible to deal with CO ₂ reaction deterioration.

This means that by reducing the water content of the charged coal by heating, the pulverized coal portion in the charged coal is easily weathered,
This is considered to be because the optically anisotropic structure formed in high-quality coal when coking causes a receding phenomenon to form a structure that is easily reacted with CO ₂ .

The receding phenomenon of the optically anisotropic structure of the high quality coal makes it difficult to use the poor coking coal or the non-caking coal from the standpoint of CO ₂ reaction deterioration.

In the conventional dry coal charging method, no consideration has been given to the above-mentioned measures for preventing weathering of pulverized coal due to drying or control of the optically anisotropic structure. Was there. That is, (a) A method of collecting dust generated by drying treatment of coal, adding heavy oil to it, granulating it to 1 to 3 mm, and mixing this with dry coal (Japanese Patent Publication No. 49-28241, 1974.7). .twenty five).

(B) Coal is dried to separate pulverized coal into coarse-grained coal, tar is added to the pulverized coal, and pelletized or compression molded,
A method of mixing with coarse particle coal to prepare charged coal (Japanese Patent Laid-Open No. 55-48284)
No., 1980.4.5).

In these methods (a) and (b), a dry treatment is carried out to separate the pulverized coal portion from which dust is generated, and heavy oil or tar is added to this to agglomerate to prevent dust generation. It is not preferable because it increases the production cost of coke because it is used.

(C) On the other hand, JP-A-56-86993 discloses a method of agglomerating with pulverized coal and a smooth roll without using a binder.

This method is economical because heavy oil or tar is not added to pulverized coal unlike (a) and (b) described above. However, there is no consideration for weathering coal.

For this reason, it becomes insufficient to reduce the caking property of the charging coal or to develop a homogeneous optically anisotropic structure in the coke of the agglomerated coal agglomerated with pulverized coal, and to prevent deterioration of the CO ₂ reaction. Not necessarily supported.

[Problems to be solved by the invention]

INDUSTRIAL APPLICABILITY The present invention is a dry coal charging method as seen in the prior art. The objective is to homogenize the optically anisotropic structure and produce high-quality coke having excellent high-temperature properties.

(Means and Actions for Solving Problems) The present invention does not use an expensive binder and reduces the water content of the charged coal to 6% or less in an atmosphere in which oxygen concentration is suppressed, preferably in an oxygen-free state, The pulverized coal portion is separated by sieving or airflow classification, and the separated pulverized coal portion is pressure-molded in an atmosphere in which the oxygen concentration is further suppressed, preferably in an non-oxidizing atmosphere, to obtain agglomerated coal. It is mixed with the above-mentioned coarse-grained coal to obtain dry-charged coal.

In the pulverized coal portion separated after drying, if it is a charging coal for the purpose of producing coke for blast furnace, it usually has an active component in the range from high-coal-quality good coking coal to low-coal-coal coking coal. Rich coal will be mixed.

In terms of weathering of coal, this pulverized coal portion is also composed of a portion that has already been pulverized due to the transportation of coking coal, etc., and is being weathered by oxygen in the air, and a portion that has been generated by the pulverization process in the coal preparation process. ing.

When such various types of fine particle coal are heated in an atmosphere containing oxygen, dried, and then made into coke as they are, the optically anisotropic structure of coke is largely determined by the unique properties of the coal. Form the optical texture of coke independently on a particle-by-particle basis.

However, when coal and petroleum-based aromatic tar and pitch are added to the pulverized coal to agglomerate, the coal particles and tar and pitch undergo a compatible reaction to develop an optically anisotropic structure of coke. To do. However, as described above, it is not preferable to use tar and pitch because the tar and pitch are expensive and therefore the production cost of coke increases.

On the other hand, the method of simply pressing the pulverized coal into agglomerated coal is
Compared to the case without agglomeration treatment, the compatibilization reaction progresses in the coking process between coal particles, but the oxygen is introduced into the agglomerated coal, which reduces the compatibilization reaction, resulting in an optical anisotropy of coke. This will impede homogenization of sexual tissue.

On the other hand, even in the coarse coal portion, weathering occurs when heated and dried in an atmosphere in which oxygen is present.

Therefore, the present invention performs drying treatment and separation of pulverized coal in an oxygen-reduced atmosphere, preferably in an oxygen-free state, and further adds pulverized coal in a oxygen-reduced, preferably oxygen-free atmosphere without a binder. It is characterized in that it agglomerates to produce agglomerated coal.

In this way, the effect of weathering of coarse-grained coal produced in the anoxic state is small, so the caking property does not decrease, and since the presence of oxygen in agglomerated coal decreases, the low-molecular-weight coal produced from high-quality coking coal is reduced. The material undergoes a compatibilization reaction that reforms low-coal coal,
A mosaic-like optically anisotropic structure is formed.

On the other hand, the fibrous or flake-like structure produced from high-quality coking coal with a high coalification degree retreats the optically anisotropic structure due to aliphatic side chains or oxygen-containing compounds generated from a low-coalification degree coal,
It has a mosaic structure.

As described above, the present invention is not limited to the agglomeration of pulverized coal as a means for preventing weathering of charged coal and dust generation of dry coal until now, and it is possible to positively and inexpensively reform pulverized coal. It is a very important thing that can be done.

Furthermore, since the caking property is restored by such agglomeration of the pulverized coal, inferior coal, non-caking coal, powder coke or the like can be mixed depending on the case. That is, the value of utility value is a carbon substance. Poor coal, non-caking coal, pulverized coke, semi-finished coke, dust collecting pulverized coal, precipitated fine pulverized coke, tar sludge, petroleum coke, and charcoal powder can be effectively used.

(Example) Hereinafter, the present invention will be described in detail based on examples.

Charging coal having the properties shown in Table 1 was used.

Example 1 The charged coal of Table 1 was dried in a dryer at 140 ° C. under N ₂ atmosphere until the water content of the charged coal became 5%, and then using a sieve, +0.5 mm portion of coarse particle coal and −0.5 mm were used. Separated into pulverized coal. Using a roll compactor was substituted for air separated pulverized coal part N _2, a plate-like mass Narusumi thickness 3.0 ± 0.2 mm in the absence of oxygen, 3 to 10 mm of beating this mass Narusumi The particle size was used.

Crushed 3-10 mm agglomerated coal was mixed with the above +0.5 mm coarse particle coal to prepare the dry charged coal of the present invention.

The prepared dry charged coal is 450mm in height, 600mm in length and 430m in width.
It was charged into a can of zinc iron plate of m with a packing density of 0.82, this can was charged into an electric furnace, and the temperature of the coal column was raised to 1050 ° C., then held for 1 hour to dry-distill and produce coke, As a result of measuring D I ¹⁵⁰ ₁₅ and CSR (the same applies to the strength after CO ₂ reaction), 84.1 and 50 were obtained.

Example 2. After separating into a pulverized coal portion of -0.5 mm and a coarse coal portion of +0.5 mm in the same manner as in Example 1, a non-caking coal having the properties shown in Table 2 was added to the pulverized coal portion. It was crushed to 0.3 mm and mixed with 20% by weight, and agglomerated carbon was produced in the oxygen-free state by using a roll compactor as in Example 1. This agglomerated coal was crushed to 3 to 10 mm and then mixed with ± 0.5 mm of coarse particle coal to produce coke under the same conditions as in Example 1.

Results of measuring D ▲ I ¹⁵⁰ ₁₅ ▼ and CSR of this coke
Got 82.5 and 45.

Comparative Example 1 was dried to 5% moisture at 140 ° C. in air using the instrumentation Nyusumi of Example 1, the dried instrumentation Nyusumi prepared, to produce a coke charging density 0.75, D ▲ I ¹⁵⁰ ₁₅ ▼ and Results of measuring CSR 81.5
And got 37.

Comparative Example 2. After separating into a pulverized coal portion of −0.5 mm and a coarse grain coal portion of +0.5 mm under the same conditions as in Example 1, the pulverized coal was crushed with a roll compactor and then crushed to 3 to After crushed coal of 10 mm, it was mixed with the coarse-grained coal portion to obtain dry charged coal.

With this drying instrumentation Nyusumi in charging density 0.82, in the same manner as in Example 1 to produce coke, D ▲ I ¹⁵⁰ ₁₅ ▼ and results of measurement of the CSR, to obtain a 82.2 and 40.

〔The invention's effect〕

As shown in the above examples and comparative examples, according to the method of the present invention, the coke strength D ¹⁵⁰ I ¹⁵⁰ ₁₅ was improved to 1.7 to 2.6, and the CSR was significantly increased to 10 13.

Even when non-caking coal having a low utility value is used, good quality coke can be produced by the usual dry coal charging method with a water content of 5%.

Claims (2)

[Claims] 1. An atmosphere in which the water content of the charged coal is adjusted to 6% by weight or less in an atmosphere in which the oxygen concentration is suppressed and separated into a pulverized coal and a coarse particle coal portion; the separated pulverized coal portion is further suppressed in the oxygen concentration. A coke producing method, which comprises press-molding without a binder into an agglomerated coal; as it is or crushed, mixed with the coarse particle portion, charged into a coke oven, and carbonized. 2. The coke producing method according to claim 1, wherein a carbon material having a low utility value is mixed with the pulverized coal portion and agglomerated.