JPH05271665A - Pitch for raw material of refining coke and its production - Google Patents

Abstract

PURPOSE:To produce the subject pitch useful as a binder for objecting a refining coke which has a large grain size, i.e., a high yield of lump coke, is heavy enough, and has a high falling strength (SI). CONSTITUTION:Quinoline-insol. matters in a coal tar pitch are precipitated and separated by using a solvent. The resulting conc. precipitate is compounded with a tar-derived heavy oil and distilled under a reduced pressure at 35 deg.C or lower to remove a light oil fraction, giving the objective pitch having a softening point of 100 deg.C or higher, a QI content of 15-50wt.%, and a beta-resin content of 7-15wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pitch used as a binder for a coke raw material for refining and a method for producing the pitch. More specifically, without special heat treatment at high temperature for a long time, quinoline-insoluble matter, toluene-insoluble matter, β-resin content, etc. are adjusted within a specific range by a simple vacuum distillation treatment method. The present invention relates to a system pitch and a manufacturing method thereof.

[0002]

2. Description of the Related Art The quality of coking raw materials for refining generally used in cupolas, etc.
High apparent specific gravity and high drop strength are required. Smelting coke with such quality,
BACKGROUND ART Conventionally, when blending coal such as caking coal or weak caking coal with an inert carbon substance such as petroleum coke, anthracite, and coke fine powder, pitches are kneaded and dried and distilled in a chamber furnace. As for the role of pitches, since a large amount of inert carbon material is blended in the production of refining coke, it is necessary to help the mutual binding between coal and inert carbon material such as coking coal and weak coking coal. In addition, it is required that the pitches be softened and melted to increase the filling rate of the charging material and to produce a dense coke (having a large apparent specific gravity).

Japanese Patent Laid-Open No. 3-277686 discloses that, as a characteristic of pitches, pitches containing 15 to 50% by weight of quinoline insoluble matter are suitable for a method for producing refining coke. Japanese Patent Publication No. 2-47516 discloses a method for producing a pitch for an electrode in which coal tars, an aromatic solvent and an aliphatic solvent are mixed and separated, and the obtained precipitate is mixed with coal tars. Heat treatment is described.

[0004]

The heat treatment in the latter case is carried out by heating and stirring the precipitate and coal tar,
Heat treatment at a high temperature of 350 to 450 ° C. for 1 to 100 hours in a reactor to increase the β-resin (TI-QI) content to 2
The reality is that it is raised to around 0 to 26%. Increasing the β-resin (TI-QI) content by heat treatment is preferable for electrode pitch because it improves the specific gravity of the fired electrode and provides a product electrode with mechanical strength and low electrical resistance, but it is necessary for heat treatment. Energy costs and work costs will be added.

On the other hand, in the case of the binder pitch as a coke raw material for refining, as a result of the study by the inventors of the present application, as disclosed in Japanese Patent Application Laid-Open No. 3-277686, pitches having a high QI content and softening It has been found that if the points are specified, it can be suitably used as a binder pitch as a coke raw material for refining without particularly increasing the β-resin (TI-QI) content. Therefore, an object of the present invention is to blend coal such as coking coal or weak coking coal and an inert carbon material such as fine coke with the binder pitch of the present invention within a range of 5 to 20% by weight and carry out dry distillation. Accordingly, it is an object of the present invention to provide a raw material binder pitch for obtaining a refining coke having a large grain size, a heavy weight, and a high drop strength, and a method for inexpensively manufacturing the binder pitch.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the inventors of the present invention have found that as a binder for coke raw materials for refining, particularly in terms of yield and drop strength of lump coke. In addition to high QI content, β-resin (TI
The present invention has been completed by finding that the content of -QI) within the range of 7 to 15% by weight can be effectively utilized.

That is, the present invention has a softening point of 100 to 120.
Quinoline insoluble matter (QI) 15 to 50% by weight, β-
A coal tar pitch for refining coke raw material having a resin content of (TI-QI) of 7 to 15% by weight and a quinoline insoluble matter in the coal tar pitch in which the quinoline insoluble matter is precipitated and separated by a solvent treatment to form a concentrated precipitate of the quinoline insoluble matter. The production of a coal tar pitch for a coking raw material for refining, which comprises blending a tar-based heavy oil and subjecting the light-oil to a softening point of 100 to 120 ° C by distillation under reduced pressure at 350 ° C or less. Is the way.

Further, the vacuum distillation condition is a temperature of 250 to 350 ° C.
Distill at a pressure of 10 to 50 mmHg to remove light oil 15
It is a method for producing a coal tar pitch for a coke raw material for refining, which is cut by up to 40% by weight. The present invention will be described in detail below.

The softening point of the pitch used as the binder for the raw material for refining coke of the present invention is at least 100 ° C. or higher, preferably 100 to 120 ° C. Softening point is 100 ° C
Below 1, especially in the summer, the binder pitch is melted in the mixing tank and coal such as caking coal or weak caking coal and a uniform mixture of inert carbon substances such as petroleum coke, anthracite, coke fine powder, etc. Will solidify into a block in the mixing tank, making it impossible to cut out. The softening point can be adjusted by the cut rate of the light oil content under the vacuum distillation conditions described below.

The QI component of the pitches referred to in the present invention is as follows:
In addition to solids such as coal fine powder contained in ordinary coal tar pitch, it particularly refers to polycondensed carbides having a high molecular weight. The QI component needs to be 15 to 50% by weight. Many documents have already been published on the method of separating the QI component from the coal tar raw material by sedimentation. Of which,
It is possible to remove it by a mechanical method such as centrifugation, but since the particle size of the QI component is extremely small, the separation speed is slow and the separation efficiency is low, such as clogging during filtration,
It is difficult to implement industrially. The same is true even if a solvent is added to lower the viscosity. Examples of methods that can be industrially advantageously carried out include JP-B-57-30159 and JP-B-60-411.
As disclosed in Japanese Unexamined Patent Publication (Kokai) No. 1, an aliphatic solvent such as hexane, octane, kerosene, naphtha and butanol and an aromatic solvent such as benzene, toluene, xylene, methylnaphthalene and phenols are used as a coal tar raw material. An effective method is to add and mix the mixed solvent of (1) to produce an insoluble product around the QI particles, and to increase the number of particles to remove by sedimentation. If the QI content in the 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 and the drum strength (DI 150) is increased. It is not preferable because it tends to decrease. The QI content can be arbitrarily adjusted by the amount of the tar-based heavy oil to be added to the concentrated precipitate of the quinoline-insoluble matter described below and the vacuum distillation treatment conditions.

The amount of β-resin is 7 to 15% by weight, preferably 9 to 13% by weight. When the amount of β-resin is less than 7% by weight, the amount of β-resin is a component that plays a central role in the caking property, and thus the caking property for the inert carbon substances is insufficient, which is not preferable. The amount of β-resin in the raw material pitch is 15% by weight
If it exceeds, the lump coke yield of refining coke of 80 mm or more is reduced and the drop strength (SI) is also reduced, which is not preferable. It should be noted that, although it depends on the type of the raw coal tar pitch, the TI content is 6 to 1 for ordinary tar-based soft pitch.
4% by weight, QI content 1-5% by weight, β-resin content 6-
About 12% by weight is contained. On the other hand, the quinoline insoluble matter in the coal tar-based pitch is precipitated and separated by the solvent treatment, and the concentrated precipitate of the quinoline insoluble matter has a TI content of 40 to 6
It contains 0 wt%, QI content of 30 to 50 wt%, and β-resin content of about 10 to 15 wt%. However, it is difficult to handle as it is. Adjust the softening point by distilling under reduced pressure and cutting off some of the solvent and light oil.

Next, a specific method for producing such a pitch for refining coke raw material will be described. First, the high QI pitch utilizes a concentrated precipitate of the quinoline insoluble matter obtained by separating the quinoline insoluble matter in the coal tar pitch by solvent treatment. Usually, de-QI pitch is produced from coal tar pitch as a raw material for needle coke production. At this time, coal tar pitch is mixed solvent of aromatic oil and aliphatic oil or solvent using naphthene hydrocarbon etc. The concentrated precipitate (pitch) having a high QI content obtained by sedimentation and separation of the QI content as extraction residue oil by the extraction method can be most advantageously used.

Conventionally, this concentrated precipitate (pitch) having a high QI content is generally unsuitable as a binder pitch for a molded carbon material, and is used as or contains carbon material aggregate (coke). By utilizing the solid content, it was only used as a low-grade fuel, and by using it in the pitch for the raw material for refining coke of the present invention, it can be utilized as a raw material for a high value-added carbon material.

The high Q which has been separated by sedimentation by the solvent extraction method described above.
The I-containing concentrated precipitate (pitch) usually has a softening point of around 90 ° C. and is hard to handle if it is not handled as it is. It is very difficult to handle it. Is preferably used in an improved state. In the present invention, the total blending ratio of the tar-based heavy oil to the concentrated precipitate (pitch) of high QI content is about 0.2 to 2 times that of the former, although it depends on the type of the tar-based heavy oil. is there.

As the heavy tar oil blended here,
Coal tar, distillation oil of coal tar, or soft pitch can be used. Especially the softening point SP by the ring and ball method is 1
A soft pitch of 0 to 80 ° C, especially 30 to 50 ° C is more preferable in terms of handling. The processing temperature is 35 as the vacuum distillation processing condition.
It may be 0 ° C. or lower, particularly 250 to 350 ° C., pressure 1
Distillation is performed in the range of 0 to 50 mmHg to cut the solvent and light oil by 15 to 40% by weight to adjust the softening point to 100 ° C. or higher. Under such vacuum distillation treatment conditions, the β-resin content is hardly increased.

Thus obtained pitch for refining coke raw material of the present invention is easily obtained with a softening point of 100 to 120 ° C., a QI content of 15 to 50% by weight, and a β-resin amount of 7 to 15% by weight. Be done. As the effect of the raw material pitch of the present invention, by using a pitch containing an appropriate softening point and QI and β-resin, coal such as caking coal or weak caking coal and petroleum coke, anthracite, coke fine powder It is basically considered that the coke structure of the binding material of the inert carbon material such as, for example, becomes a mosaic-like homogeneous coke grain size and SI4 / 50 value improves, but at this time, As in the case of the formed carbon material, the cohesiveness of the pitch itself, which replenishes the cohesiveness of the coke raw material, may be due to replenishment from coal such as cohesive coal or weak cohesive coal. It is considered that if the amount of β-resin is too large, the quality is rather deteriorated.

[0017]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. (Production of product pitch) As a pitch raw material, a mixed solvent of aromatic light oil and aliphatic kerosene is mixed and stirred with soft pitch (softening point; 35 ° C.) of a coal tar distillation residue. De-Q as a raw material oil for needle coke as a clear liquid
When obtaining I-pitch, a concentrated precipitate of high QI (softening point; 90 ° C), which was precipitated using QI formed as a nucleus, was extracted from the lower part, and in order to improve the handling property, soft pitch and tar-based A high QI pitch was prepared by blending a quality oil and adjusting the softening point to 40 ° C.

The properties of the high QI pitch and the pitch of the coal tar distillation residue are shown below.

[Table 1]

The properties of the product pitch obtained by treating the coke raw materials A, B, C, D and E in which these pitches are mixed alone or appropriately, under the reduced pressure distillation conditions and heat treatment conditions shown in Table 1, are shown. Collectively shown in Table 2 below. For the purpose of comparison, the coke raw material E was heat-treated in a reactor at 400 ° C. for 10 hours to increase the QI and β-resin, and is usually used for an electrode pitch.

[0020]

[Table 2]

(Evaluation as raw material for refining coke) Standard blended coal consisting of 50 parts by weight of two kinds of coking coal or weak coking coal, 24 parts by weight of petroleum coke and 16 parts by weight of coke fine powder, and each of the above products. Pitches A, B, C, D, and E were uniformly blended at a ratio of 10 parts by weight, and dried in a chamber-type coke oven to obtain a refined coke. Table 3 shows the quality of the obtained refined coke (ratio of coke of 80 mm or more (weight%) and drop strength (SI4 / 50)).

[0022]

[Table 3]

[0023]

The pitch for the raw material for refining coke of the present invention is
By using it as a binder pitch of a refining coke raw material, it is possible to produce a refining coke having a large grain size, that is, a high lump coke yield, a heavy weight, and a high drop strength (SI). Further, the raw material pitch of the present invention can easily produce a concentrated precipitate containing a high QI content generated as a residue in the conventional de-QI pitching process for needle coke by a simple vacuum distillation treatment, so that it can be used in a special method such as increasing β-resin. The cost required for the heat treatment is reduced, and the concentrated precipitate containing a high QI content, which was used only for the low-grade fuel level, can be effectively used.

Claims (3)

[Claims] 1. A softening point of 100 to 120 ° C. and a QI content of 1
A pitch for smelting coke raw material comprising 5 to 50% by weight and an amount of β-resin of 7 to 15% by weight. 2. A quinoline insoluble matter in coal tar pitch is precipitated and separated by solvent treatment, concentrated quinoline insoluble matter is mixed with tar heavy oil, and the mixture is subjected to vacuum distillation treatment at 350 ° C. or lower to obtain a softening point. A method for producing a pitch for a raw material for smelting coke, which comprises cutting light oil so that the temperature becomes 100 to 120 ° C. 3. The reduced pressure distillation condition is a temperature of 250 to 350 ° C.,
Distill at a pressure of 10 to 50 mmHg to remove light oil 15
The method for producing a pitch for a smelting coke raw material according to claim 2, wherein the pitch is cut by up to 40% by weight.