JPS61188487A - Production of coke - Google Patents

Abstract

PURPOSE:To obtain coke having excellent coke strength and high-temperature properties without use of an expensive caking coal, by carbonizing in a coke oven a specific massively molded coal as it is or a mixture of a powder obtained by breaking the specific massively molded coal with a coarse powder coal fraction separated from a feed coal. CONSTITUTION:The moisture of a feed coal is adjusted to 6wt% in an atmosphere having controlled O2 concentration. The coal is separated into a finely divided coal fraction and a coarse powder coal fraction by means of a sieve or air classification. The finely divided coal fraction is, if necessary, mixed with a carbonaceous substance having a low utility value and press molded into a massively molded coal without use of a binder in an atmosphere having a controlled O2 concentration. The massively molded coal is either carbonized in a coke oven as it is, or broken, mixed with the coarse powder coal fraction obtained by the air classification and carbonized in a coke oven, thereby to obtain a high-quality coke having an excellent cold strength, a coke strength DI<150>15 of 1.7-2.6 and a strength after reaction with CO2 of 10-13 and a uniform optical anisotropy.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a coke manufacturing method, and particularly to a method for charging dry coal during coke manufacturing and a method for using unused carbon materials such as poor quality coal and non-caking coal. It is.

[Conventional technology]

Blast furnace coke is required to have high cold strength and low CO2 reaction deterioration during hot heating.

However, high-quality coking coal for producing coke for blast furnaces is currently and in the future in short supply, and is also expensive.

For this reason, the coke industry has developed various pre-treatment techniques for charged coal, and is attempting to produce high-quality coke using unused carbon materials such as inferior coking coal or non-caking coal.

One of these pre-treatment techniques is the dry coal charging method, which is used in the coke industry by drying the charged coal.

When this dry coal charging method is applied to charged coal, it is effective in saving energy and improving the cold strength of coke.

However, it does not necessarily respond to CO2 reaction deterioration.

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This means that by reducing the moisture content of the charged coal through heating, the pulverized coal portion in the charged coal becomes more susceptible to weathering.
This is thought to be because the optically anisotropic structure that is generated in high-quality coal when coked causes a regression phenomenon, forming a structure that is easily reacted with CO2.

This regression of the optically anisotropic structure of good quality coal makes it difficult to use poor quality coking coal or non-caking coal from the standpoint of CO2 reaction deterioration.

In the conventional dry coal charging method, no consideration was given to preventing weathering of the pulverized coal by drying or controlling the optically anisotropic structure, as described below, and the focus was only on preventing dust generation from the pulverized coal. was. In other words, (,) the dust generated by drying coal is collected,
A method of adding heavy oil to this, granulating it to 1 to 3N, and mixing it with dry coal (% Publication No. 49-28241).

1974, 7.25’).

(b) A method of drying coal to separate pulverized coal into coarse granular coal, adding tar to the pulverized coal to form pellets or compression, and mixing with coarse granular coal to make charging coal (Japanese Patent Laid-Open No. 55 −
No. 48284, 1980, 4.5).

These methods (,) and (b) involve drying, separating the part of the pulverized coal that generates dust, and adding heavy oil or tar to it to agglomerate it and prevent dust generation. The use of coke increases the cost of producing coke, which is not desirable.

(c) On the other hand, as a method of agglomeration using smooth rolls without using pulverized coal and a binder, JP-A No. 56-869
There is No. 93.

This method is economical because heavy oil or tar, which is different from the above-mentioned (a) and (b), is not added to the pulverized coal. However, there is no consideration given to preventing coal from weathering.

As a result, the caking property of the charged coal decreases, or the coke in the agglomerated coal portion, which is made by agglomerating pulverized coal, is not sufficiently developed with a homogeneous optically anisotropic structure. Not necessarily supported.

[Problem that the invention seeks to solve]

In the dry coal charging method as seen in the prior art, the present invention not only prevents dust generation in the pulverized coal portion, but also prevents weathering of the charged coal and allows coke to be formed without using expensive caking agents in the pulverized coal portion. The aim is to homogenize the optically anisotropic structure and produce high-grade coke with excellent high-temperature properties.

(Means and effects for solving the problem) The present invention reduces the moisture content of charged coal to 6% or less in an atmosphere with a suppressed oxygen concentration, preferably in an oxygen-free condition, without using an expensive caking agent. The pulverized coal portion is separated by a sieve or air classification, and the separated pulverized coal portion is further pressure-molded in an atmosphere with suppressed oxygen concentration, preferably in a non-oxidizing atmosphere, to produce agglomerated coal. It is mixed with air-classified coarse particle coal to form dry charged coal.

The pulverized coal separated after drying usually contains active components ranging from high quality coking coal to low coking coal if the charging coal is intended for the production of coke for blast furnaces. Rich coal will be mixed in.

From the perspective of coal weathering, this pulverized coal portion consists of a portion that has already been pulverized by transportation of coking coal and is undergoing weathering due to oxygen in the air, and a portion generated by the pulverization process in the coal preparation process. ing.

When these various types of fine particle coal are heated and dried in an atmosphere containing oxygen and turned into coke in that state, the optically anisotropic structure of the coke is due to the unique properties of the coal. For the most part, the optical structure of coke is formed independently in particle units.

However, when coal/petroleum-based highly aromatic tar and pitch are added to the pulverized coal portion and agglomerated, a compatibility reaction occurs between the coal particles and the tar-pitch, and the optically anisotropic structure of the coke develops. do. However, the use of the above-mentioned tar and pitch is not preferable because it increases the production cost of coke because tar and pitch are expensive.

On the other hand, the method of simply pressurizing pulverized coal to make lump coal is
Compared to the case without agglomeration treatment, the compatibility reaction between coal particles during the coking process progresses, but the compatibility reaction is small due to oxygen entering the agglomerated coal, and the optical difference of coke is small. This will inhibit the homogenization of the tropic tissue.

On the other hand, if the coarse particle coal portion is heated and dried in an atmosphere containing oxygen, weathering will occur.

Therefore, the present invention performs drying treatment and separation of pulverized coal in an atmosphere with a reduced oxygen concentration, preferably an oxygen-free condition, and further adds pulverized coal without a binder in an oxygen-free atmosphere with a reduced oxygen concentration. It is characterized by producing lump coal by pressure forming.

Coarse coal produced under anoxic conditions has little effect on weathering, so its caking properties do not deteriorate, and since agglomerated coal is known to have a reduced presence of oxygen, A compatible reaction in which molecular substances modify low-coalization coal progresses,
Forms a mosaic-like optically anisotropic structure.

On the other hand, the optically anisotropic structure of the fibrous or leaf-like structure produced from high-quality coking coal with a high degree of coalification is regressed by K, such as aliphatic side chains and oxygen-containing compounds generated from coal with a low degree of coalification.
It becomes a mosaic-like structure.

As described above, the present invention is not limited to the agglomeration of pulverized coal as a means of preventing weathering of charged coal and dust generation of dry coal, but also actively and inexpensively reforming pulverized coal. This is an extremely important thing that can be done.

Furthermore, since the caking property is restored by such agglomeration of pulverized coal, inferior quality coal, non-caking coal, coke powder, etc. can be mixed in depending on the case. That is, the value of utility value is carbon material. Low quality coal, non-caking coal, coke powder, semi-coke, dust-collected pulverized coal, precipitated pulverized coke, tar sludge 2 petroleum coke, charcoal powder, etc. can be effectively used.

(Example) The present invention will be described in detail below based on examples.

The charging coal used had the properties shown in Table 1.

Table 1 Example 1 The charged coal in Table 1 was dried in a dryer at 140°C under N2 atmosphere until the moisture content of the charged coal became 5%, and then it was sieved to +0.5%.
It was separated into coarse particle coal of am part and pulverized coal of -0.5ms. The separated pulverized coal was heated to a thickness of 3.0±0 in an oxygen-free condition using a roll connoctor in which the air was replaced with N2.
．． The lump coal is made into 2 pieces of plate-shaped lump coal, and this lump coal is crushed to produce 3~
The particle size was 10 dragons.

Dry charged coal of the present invention was prepared by mixing 3 to 10 pieces of crushed agglomerated coal with the coarse particle coal of +0.5 order.

The prepared dry charging coal was heated to a height of 450 mttt and a length of 60 mttt.
0Il! The coal was charged into a galvanized iron plate can with a width of 4301 m at a charging density of 0.82, and the can was charged into an electric furnace, and after the coal column temperature rose to 1050°C, it was held for 1 hour and carbonized. Produce coke, D115 and C3R (C0
After two reactions, the strength (the same below) was measured and the results were 84.1 and 50.

Example 2, 10, 5 Dragon's pulverized coal part and +
After separating into the coarse particle coal part of 0.5 tn*, non-caking coal having the properties shown in Table 2 was crushed to -0.3 weight and mixed with 20% by weight into the pulverized coal part, and the same as in Example 1 was added. Agglomerated coal was produced in an oxygen-free condition using a roll-con/rubber. After crushing this lump coal into 3 to 1011 IK, 10.5 mg
coke was produced under the same conditions as in Example 1.

The DI and C8R of this coke were measured and found to be 82.5 and 45.

Table 2 Comparative Example 1 The charged coal of Example 1 was dried in air at 140°C to a moisture content of 5% to prepare dry charged coal, and coke was produced with a charging density of 0.75, and DI and C8R The results of measurement were 81.5 and 37.

Comparative Example 2゜Under the same conditions as Example 1, -0.5mm pulverized coal portion and +
After separating into coarse particles of 0.5 mW, the pulverized coal is made into agglomerated coal using a roll compactor, and then crushed into 3 to 10 m
The crushed coal was mixed with coarse particle coal to obtain dry charging coal.

Example 1 This dry charged coal was prepared with a charging density of 0.82.
Coke is produced in the same manner as DI and C8
As a result of measuring R, 82.2 and 40 were obtained.

〔Effect of the invention〕

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

Furthermore, even if non-caking coal, which has low utility value, is used, it is possible to produce high-quality coke compared to the usual method of charging dry coal with a moisture content of 5%.

Claims (2)

[Claims] (1) Adjust the moisture content of the charged coal to 6% by weight or less in an atmosphere that suppresses oxygen concentration, separate it into pulverized coal and coarse coal, and then separate the separated pulverized coal in an atmosphere that suppresses oxygen concentration. A method for producing coke, which comprises pressurizing the coal without using a binder to form lump coal, which is then mixed with the coarse particles either as it is or after being crushed, and then charged into a coke oven and carbonized. (2) The coke manufacturing method according to claim (1), characterized in that a carbon material with low utility value is mixed into the pulverized coal portion and agglomerated.