JPS59136382A - Preparation of needle coke - Google Patents

Abstract

PURPOSE:To obtain needle coke having low puffing, suitable for preparing graphitized materials such as artificial graphite electrodes, etc., by adding a polyphenyl (derivative), etc. to a hydrocarbon substance of coke source. CONSTITUTION:(A) 100pts.wt. hydrocarbon substance (e.g., coaly coal tar and/or coal tar pitch, etc.) is blended with (B) usually 1-30pts.wt. (preferably 1- 20pts.wt.) polyphenyl (derivative) and/or residual oil obtained by producing it, to give the desired needle coke. An (alkyl) diphenyl, triphenyl hydride, etc. and a residual oil consisting essentially of tetraethyl diphenyl or terphenyl, etc. may be cited as the component B.

Description

[Detailed description of the invention] The present invention relates to the production of needle coke.

More specifically, the present invention relates to a method for producing low-puffing needle coke suitable for producing graphitized products such as artificial graphite electrodes.

Needle coke, which has been conventionally used to produce graphitized products such as artificial graphite electrodes, is generally produced in a dilate coker using coal tar and/or coal tar pitch, or heavy petroleum oil as a raw material.

-1 = 450-550℃, pressure 1-6, 5 K97cnl
It is manufactured by being processed under the following conditions and then fired in a rotary kiln, shaft furnace, rotary hearth furnace, etc.

To produce graphitized products such as artificial graphite electrodes, the coke produced by the method described above is crushed and sieved.

The particle size is adjusted to an appropriate composition, a binder pitch is added thereto, the mixture is kneaded, the mixture is molded using an extrusion molding machine or a press molding machine, and after passing through a firing process, it is produced by graphitizing. In its manufacture, this graphitized material undergoes a graphitization step, during which heating is performed at approximately 2000 to 3000°C.

However, during the production of this graphitized product, a puffing phenomenon (swelling) occurs during the graphitization process due to the properties or chemical composition of the coke.Therefore, for example, an artificial graphite electrode produced using the coke has a strength of 1. This causes troubles such as breakage during use, resulting in a significant decrease in productivity in the electric furnace industry. The cause of puffing is that the carbon-sulfur bonds in coke become unstable at high temperatures, and sulfur is liberated. It is explained that this occurs because hydrogen sulfide, which is produced by the combination of free sulfur and hydrogen, pushes and spreads the coke structure when it escapes to the outside of the coke.

In order to prevent puffing caused by sulfur, it is originally easy to produce coke from raw materials with low sulfur content, but in recent years it has become difficult to obtain coke sources with low sulfur content. The transition to high sulfur coke sources has inevitably led to an increase in the aforementioned puffing problem.

Since this puffing phenomenon has an adverse effect on the graphitized material as described above, various studies have been carried out to prevent this phenomenon in the graphitization process.

For example, in order to prevent puffing during the manufacture of artificial graphite electrodes, oxides such as iron, calcium, aluminum, or manganese are added to the mixture of smoldered coke and binder pitch as anti-puffing agents before extrusion and firing of the electrodes. The puffing phenomenon was prevented by adding hydrogen sulfide to capture the hydrogen sulfide generated in the graphitization process after firing.

However, since this method uses a solid anti-puffing agent, it is very difficult to disperse it uniformly, and in order to obtain the anti-puffing effect evenly, a large amount of anti-puffing agent and mixing techniques are required. It was. Also, in this method, the anti-puffing agent acts from around the coke particles.

Another disadvantage was that it was difficult to penetrate the inside of coke particles.

In order to solve these drawbacks, for example, 1.
Derate code as disclosed in No. 110190
An effective method is to add a small amount of anti-puffing agent before charging the coke source to the card drum. However, when using a solid anti-puffing agent such as iron oxide, this method requires a special technique for uniformly dispersing the anti-puffing agent.

Further, uniform dispersion can be easily achieved by using an organometallic complex such as ferrocene that dissolves in the coke source, but these are too expensive.

Furthermore, although this method was effective in preventing puffing, it also led to an increase in the ash content of the coke.

In order to remove nitrogen or sulfur atoms from coke, for example, the method disclosed in Japanese Patent Application No. 57-64817 is to burn raw coke at a temperature range of 1300 to 1500°C for as long as possible in the coke baking process. It is a method of grilling, and has achieved some results.

As a result of intensive research, the present inventors have invented a method for preventing puffing during the graphitization process during the production of graphitized products.

The present invention involves adding polyphenyl, polyphenyl derivatives, and the residues produced by producing them to a hydrocarbon material serving as a coke source.

These organic substances dissolve in hydrocarbon substances that serve as coke sources, and since many of these organic substances dissolve at room temperature, uniform dispersion is easy. Moreover, residual oil is cheap.

Excellent as an additive.

Coke obtained from a coke source to which these are added has a low ash content and is significantly less prone to puffing during the graphitization process.

That is, the present invention provides a method for producing coke by charging a hydrocarbon material serving as a coke source into a coking production apparatus, and in which polyphenyl, polyphenyl derivatives, and residual oil from which they are produced are added to the hydrocarbon material. This is a method for producing needle coke characterized by adding one type or a mixture of two or more types selected from the following.

Next, the present invention will be explained in detail.

The hydrocarbon substance used as a coke source in the present invention is raw material 1 for producing needle coke, such as coal-based coal tar and/or coal tar pitch, or petroleum-based heavy oil for producing needle coke, etc. .

When producing needle coke from coal-based coal tar and/or coal tar pitch, coal tar and/or
Alternatively, it is necessary to remove the quinolinated content contained in coal tar pitch. As a method for removing the quinoline solution, a filtration method, a centrifugation method, a solvent purification method, etc. can be adopted.

6- The polyphenyl, the polyphenyl derivative, and the residual oil from which they are added to the coking raw material in the present invention are all produced by heating and condensing benzene. Polyphenyl used in the present invention.

These are polyphenyl derivatives id + diphenyl, alkyldiphenyl, hydrogenated triphenyl, etc., and the residual oil from which they are produced is the oil remaining after the polyphenyl etc. have been separated and removed (hereinafter referred to as polyphenyl residual oil).

Of course, since the residual oil is the oil remaining after the target polyphenyl has been separated and removed, there are residual oils mainly consisting of tetraethyl diphenyl and residual oils mainly consisting of terphenyl, both of which are applicable to the present invention. Can be used.

Graphitized products manufactured using coke obtained by adding these materials to coal tar and/or coal tar pitch or petroleum heavy oil, which are raw materials for producing needle coke, are This results in reduced flying. Polyphenyl, polyphenyl derivatives, and residual oils from the production of them tend to turn into carbides with three-dimensional crosslinks due to thermal 7-9 polycondensation reactions, so they are added to coke raw materials. It is thought that the coke forms crosslinks consisting of three-dimensional bonds in the microstructure of the coke, making the coke extremely strong. This phenomenon does not directly deal with heteroatoms such as sulfur, which are thought to be the cause of puffing, as in the past, but rather with swelling that can sufficiently withstand the sudden generation of such gases. It is thought that strong coke is formed.

The additives used in the present invention also have the advantage of not increasing ash content like metal compounds.

These additives are added to the hydrocarbon material of the coking raw material, but when using the above-mentioned coal-based coal tar and/or coal tar pitch, they can be added either before or after removing the quinolinated content. .

The amount added is 1 to 30 parts, preferably 1 to 20 parts, per 100 parts of the coke source hydrocarbon material. If the amount is less than 1 part, there is no significant effect, and if more than 1 part 308 is added, crystal growth of the coke produced therefrom will be inhibited and the characteristics of needle coke will be impaired, which is not preferable.

First, green coke is produced from coking raw materials to which these substances have been added in a dilate coker under normal conditions, and then the green coke is burned in a rotary kiln to obtain coke.

The coke produced in this manner was pulverized to adjust the particle size, and a mixture containing binder pitch was pressure-molded, then fired and graphitized.The graphitized product had little puffing phenomenon.

Next, an explanation will be given using an example.

Example 1 7 parts of residual oil mainly consisting of tetraethyl diphenyl was added to 100 parts of coal tar soft pitch containing 0.1 part of quinoline solution to produce raw coke.
It was baked at 400°C to produce @burned coke.

Next, the burned coke is crushed, 50 parts of the 20-70 mesh pulverized material and 509 parts of the 100 mesh or less pulverized material are mixed with a binder pitch, and extrusion molded into a molded product (diameter 20 mm, length loO mm). )It was created.

This molded body was fired at 900°C for 6 hours to create a fired test piece. Puffing was measured by setting the previously prepared fired test piece in a horizontal Tamman furnace and measuring the elongation rate in the length direction of the test piece in a temperature range from room temperature to 2600° C. using a diradometer. The results are shown in the table.

Example 2 15 parts of residual oil mainly composed of terphenyl was added to 100 parts of the coal tar pitch used in Example 1 to produce raw coke, which was then baked at 1400°C to obtain burned coke. Ta.

The subsequent preparation of the baked test piece and the testing method were the same as in Example 1. The results are shown in the table.

Comparative Example Using the coal tar soft pitch used in Example 1, a fired test piece was prepared and tested in the same manner as in Example 1, without adding the additives used in the present invention, and compared. It was used as data. The results are shown in Table 10.

As shown in the table above, the present invention improves the drawbacks of conventional coke and can be used industrially.

11- 680-

Claims (1)

[Claims] 1. A method for producing coke by charging a hydrocarbon material serving as a coke source into a coke production apparatus, wherein the hydrocarbon material contains polyphenyl. A method for producing needle coke, which comprises adding one or a mixture of two or more selected from polyphenyl derivatives and residual oils from which they are produced.