JPS5852924B2 - Method for producing raw coke composition for producing carbonaceous material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a raw coke composition capable of producing a high-density carbonaceous material by direct molding and firing from raw coke without using a binder.

Raw coke with an appropriate volatile content is finely pulverized using an appropriate method, then pressure molded alone without using a binder such as binder pitch, and then heated for 70 minutes in an inert gas atmosphere.
It is already known (for example, (See JP-A-51-15050 and JP-A-53-79789 of the present applicant).

The specific gravity and compressive strength of the self-sintering carbon material obtained by press-molding and sintering raw coke fine powder alone without using a binder such as binder pitch are determined by the particle size of the raw coke fine powder. The smaller the particle size and the closer the particle shape is to a sphere, the more dog-like it becomes, and the higher the firing temperature, the larger the value.

For example, premium grade raw petroleum coke with a volatile content of 8.75% is ground in a mill for 0.5 hours and 8 hours to form fine powders with average particle sizes of about 11μ and 6μ, respectively. 9 into a mold with a diameter of 8cIfL,
1oo.

9 kg/c IIL in an inert atmosphere after pressure molding.
The bulk specific gravity of each carbon material obtained by firing at 00°C is 1.
37 and 1.47, compressive strength is 480 to 9/crlt
and 1300kg/cI? L, and it is recognized that when it is pulverized, it becomes a carbonaceous material with a density of Hokihanawa.

Furthermore, when this carbon material with a bulk specific gravity of 1.47 is fired at 1400'C, the bulk specific gravity is 1.71 and the compressive strength is 2000~250'Ok.
When a high-density carbonaceous material of y/i is heated to around 3000° C., a graphite material having a bulk specific gravity of 1.84 and a compressive strength of 900 to 1100 is obtained.

However, the fatal flaw in the method of directly molding and sintering raw coke fine powder is that the molded sintered body cracks, and in particular, it is caused by cracks called "pull cracks" that occur when the molded product is extruded from the mold. Cracks occur.

This is mainly due to the fact that the frictional force between the raw coke fine powder particles and between the fine powder and the inner surface of the mold increases during molding, resulting in uneven density of the press-formed product and uneven shrinkage during firing. In particular, with regard to pull-out cracks, it is believed that the friction with the inner surface of the mold increases significantly when extruding the molded product from the mold, and therefore it is important to reduce such frictional force as much as possible. is necessary.

The present inventors have previously discovered a means that can significantly reduce the frictional force between particles of fine raw coke powder and between such fine powder and the inner surface of a mold, as described above, and as a result, can effectively prevent pull-out cracks. A mixture obtained by mixing fine raw coke powder with 1 to 15% by weight of water or a monohydric alcohol having 4 or more carbon atoms and liquid at room temperature such as butyl alcohol, octyl alcohol, benzyl alcohol, preferably water. proposed a method of molding and sintering the
-4.018 Publication).

Methods for mixing water into raw coke include adding and mixing the specified amount of water to fine raw coke powder, and another method to make it easier to mix water is mixing raw coke in water in the presence of a dispersant. A method of adjusting the moisture content to the specified amount after wet pulverization was shown.

The present inventors have now discovered an efficient method for producing an intimate mixture of the above-mentioned raw coke fine powder and a specific amount of water or monohydric alcohol, which can be molded into molds and self-sintered while effectively preventing pull-out cracks. We developed a new method that can be called a semi-wet method.

That is, in the present invention, raw coke that has been coarsely ground to about 20 to 30 meshes is finely ground to a desired particle size, preferably an average particle size of 6 μm or less, in an amount of 20 to 35% by weight based on the weight of the raw coke. The grinding process is carried out under semi-humid conditions in the coexistence of water or a monohydric alcohol having a carbon number of 4 or more and liquid at room temperature, and then the water or monohydric alcohol content is adjusted to 1 to 15% by weight on the same basis as above. The present invention provides a method for producing a raw coke composition for producing carbonaceous material, which is characterized by the following.

The method of the present invention is particularly useful for producing a raw coke composition suitable as a raw material for producing high-density carbonaceous material that exhibits a bulk specific gravity of 1.75 or more after graphitization treatment at around 3000°C.

That is, according to the method of the present invention, a finely powdered raw coke composition suitable for such purposes has an average particle size of 6μ or less, 75% or more of the total particle size is 10μ or less, and the particle shape is substantially spherical. Products can be manufactured easily and efficiently.

In this specification, the particle size is measured by electron microscopy and means that 75% or more of the total particle size is below the indicated particle size, and the average particle size is measured by the liquid phase sedimentation method using an Andreazen pipette. It is.

The dry pulverization method using a grinding method that the present inventors previously proposed as a method of mixing a specific amount of water into fine raw coke powder is not suitable for pulverizing raw coke coarse particles to a particle size of several microns or less. It may be inadequate or too time consuming and inefficient and will often require a separate process, usually a wet grinding process, to pulverize the raw coke.

Furthermore, after wet pulverization, the carbonaceous material produced from the composition obtained by adjusting the water content within the specified range has a higher bulk specific gravity and strength than the carbonaceous material produced from the composition obtained by the semi-wet method according to the present invention. was found to be clearly inferior.

As an example, one of the same petroleum raw coke (regular grade, volatile content 14.1%) was wet-pulverized for 5 hours using a vibrating mill, and the moisture content was adjusted to 5% based on the raw coke. 4μ fine powder, the other is 3μ for raw coke
Both fine powders with an average particle size of about 4μ obtained by grinding with an edge runner for 5 hours in the coexistence of 0% water and then adjusting the water content to 5% with respect to raw coke were placed in a mold with a diameter of 3CrrL. 900° after pressure molding to 100 okg7cti
C! The results of measuring the bulk specific gravity of the carbon material obtained by this firing and the graphitized material obtained by graphitizing it at around 3000° C. are as follows, and the difference is clear.

Wet method Semi-wet method (Bulk density of product fired at 900℃) 1.34 1.5030
00℃ graphitized bulk specific gravity 1.63 1.85 Observation using an electron microscope of the fine powder before molding and sintering shows that the particle size is almost the same for both methods, but the shape of the particles is slightly different from that of the edge runner. In wet pulverization (the present invention), the fine coke particles had a nearly spherical shape, whereas in vibrating mill wet pulverization, they had a slightly angular shape, probably due to the strong impact force.

The semi-wet pulverization of the present invention can be carried out using any pulverizer as long as it is a pulverizer.

Typical examples of such crushers include a strainer, an edge runner, an attrition mill, and a ring roll mill.

Due to their mechanism, these crushers are not suitable for wet crushing and are generally used for dry crushing. It has been found that particles tend to escape between the rollers and the grinder body, scatter before reaching the target particle size, and in practice, it is extremely difficult and inefficient to grind particles to a few microns or less.

However, according to the semi-wet pulverization, which is a feature of the present invention, that is, 20 to 35% by weight of water (or monohydric alcohol) is added to the raw coke at the initial stage of pulverization, and the raw coke is pulverized by a grinding method. Despite its hydrophobic nature, added water uniformly wets the raw coke powder and increases particle friction (as a result, not only direct grinding by rollers, etc., but also the mutual grinding effect of particles) Furthermore, it is easy to concentrate the crushed material under the roller using a scraping blade or the like, so it is thought that fine pulverization to an average particle size of several microns or less can be easily achieved.

The amount of water or monohydric alcohol in the semi-wet pulverization of the present invention is 20% based on the weight of raw coke as described above.
-35%, particularly preferably 25-30%.

If it is more than 35%, the crushed material will adhere to the contact surfaces of the crusher such as rollers, making it difficult to work smoothly, while if it is less than 20%, the scattering of fine powder will be even more pronounced than during dry crushing, and both are unsuitable for continued crushing. Ta.

The raw coke fine powder semi-wet-pulverized in this way has too much water or alcohol content to be press-molded as it is, so water or monohydric coke is added until the content reaches 1 to 15% by weight based on the raw coke. The desired composition is obtained by evaporating the alcohol.

This evaporation is normally achieved by heating, but the purpose can also be achieved by stopping the supply of water or alcohol in the late stages of grinding.

The pulverized composition is usually compressed with a roller or the like to form a hard thin plate shape, and since it is difficult to obtain a uniform molded product as it is, it is crushed to form a composition in the form of soft aggregates.

The steps of molding and sintering the composition obtained by the method of the present invention are completely the same as those of the conventional method.

The method of the present invention can be applied to the production of carbonaceous material from any raw coke fine powder by molding and self-sintering, regardless of whether it is coal-based or petroleum-based.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Using an edge runner with a dish diameter of 1.6 m and two rollers weighing about 1 t rotating at 18 rpm,
Take 15 kg of raw petroleum coke with a volatile content of 12.3% that has been roughly crushed to about 0 mesh, and
, 25, 30, 35 and 40% by weight of water were added, and the water content of the crushed material was measured every 30 minutes to ensure that the water content did not fluctuate by more than ±2% (weight percent relative to raw petroleum coke) to determine the amount of evaporated water. Grind while rehydrating.

Dry pulverization with addition of water was also carried out using the same raw coke and the same equipment.

In dry grinding and grinding with a water addition amount of 10 and 15%, the scattering of fine powder is significant and it is extremely difficult to concentrate the crushed material under the rollers, especially when the water addition amount is 10 and 15%. It was observed that this tendency was rather more remarkable in the case of 15%.

However, when the amount of water added is 20%, the scattering of fine particles is considerably reduced, making it easier to concentrate the crushed materials under the rollers, and when the amount of water added is 25 and 30%, the scattering of fine particles almost disappears, and the crushed materials are It easily concentrated under the roller and shattered into a thin layer.

When the amount of water added is 35%, crushed materials start to adhere to the roller,
When the amount of water added was 40%, the amount of adhesion became extremely large, and the rotation of the rollers caused it to be blown out of the vessel, making it impossible to continue pulverization.

Table 1 shows the relationship between the amount of water added after pulverization for 5 hours and the average particle size, particle size, and yield of the resulting fine raw coke powder (yield of the raw coke itself excluding added water).

When the amount of water added is 30%, the fine powder obtained by pulverization for 5 hours is dried while being crushed, and the water content is adjusted to 1 to 15% based on the weight of the raw coke. 3
It was placed in a cIfL mold, pressure-molded to 1000 kg/crA, fired to 900°C, and then heated to 300°C.
It was heated to around 0°C and graphitized.

Table 2 shows the relationship between the moisture content of the raw coke composition, the conditions during molding, the υ-formed shapes, the bulk weight of the 900°C baked product and the graphitized product.

On the other hand, when 25 g of the water-free fine powder obtained by dry grinding is pressure-molded to 1000 kg/cti in the same manner as above, the frictional force between the raw coke and the mold is large;
When the molded product was extracted from the mold, there were significant punch-out cracks, making it practically impossible to mold the product.

Example 2 15k of raw pitch coke with a volatile content of 9.41% coarsely crushed into 20 to 30 meshes in the same edge runner as in Example 1
20, 25, 30 and 35% by weight of octyl alcohol were added thereto, and pulverized while replenishing alcohol so that the alcohol amount did not fluctuate by more than ±2% by weight (based on fresh coke).

When the amount of alcohol added was 20%, scattering of fine powder was observed, but when the amount of alcohol added was 25% and 30%, there was almost no scattering of fine powder.

The crushed material easily concentrated under the roller and was crushed into a thin layer.

When the amount of alcohol added was 35%, the crushed material adhered to the rollers, making it difficult to continue crushing smoothly.

The average particle diameters of the fine powders after pulverization for 5 hours in the coexistence of 25 and 30% by weight of octyl alcohol were 3.9μ and 4.0μ, respectively, and both were 9μ or less in terms of particle size.

The fine powder obtained when the amount of alcohol added is 25% is crushed and dried to reduce the amount of alcohol to 1 to 100% of the raw coke.
The raw coke mixture obtained by adjusting the concentration to 15% was put into a mold with a diameter of 3 crrL, and the mixture was heated to 1000 kg/cvi.
Pressure molded.

When the alcohol content was 1%, slight extraction cracks occurred, but when the alcohol content was 3 to 8%, no extraction cracks were obtained at all.

Furthermore, when the alcohol content was 10%, only the oozing of alcohol was observed during molding, and when the alcohol content was 15%, most of the sample was extruded out of the mold during molding.

The thus formed product was fired at 900°C and then graphitized at around 3000°C.

The bulk specific gravity of the 900'C fired product was 1.47 to 1.52, and the bulk specific gravity of the graphitized product was 1.78 to 1.84.

Example 3 15 kg of raw petroleum coke with a volatile content of 14.1%, which had been ground to 150 meshes (Tyler), was placed in the same edge runner as in Example 1, and 28% by weight of n-butyl alcohol and benzyl alcohol were added to it. were added and crushed for 5 hours while replenishing alcohol so that the alcohol amount did not fluctuate by more than ±2% by weight (based on fresh coke).

During this time, there was almost no scattering of fine powder, and the crushed materials were easily concentrated under the roller and were crushed into a thin layer.

The average particle size of the obtained fine powder was 4.1μ (particle size 9μ or less)
Met.

The fine powder was crushed and dried so that the alcohol content (based on fresh coke) was 5% by weight, and 25 g of the dried product was placed in a mold with a diameter of 3 cIfL and pressure-molded to 1000 kg/-.

The resulting green body had no extraction cracks and had a rating of 9oo0c.
After firing, it was heated to around 3000°C to graphitize it.

Claims (1)

[Claims] 1. Raw coke is pulverized by a grinding method in the presence of 20 to 35% by weight of water or a monohydric alcohol having a carbon number of 4 or more and liquid at room temperature based on its weight, and then the water or monohydric alcohol content is A method for producing a raw coke composition for producing carbonaceous materials, which comprises adjusting the amount of coke to 1 to 15% by weight on the same basis.