JPH0370791A - Production of pitch coke - Google Patents

Abstract

PURPOSE:To obtain massive pitch coke having specifically low sulfur content, high yield of carbonization and large particle diameter by hydrogenating a coal tar raw material under a specific condition, subjecting to delayed coking to give raw pitch coke and carbonizing. CONSTITUTION:A coal tar raw material is hydrogenated in the presence of a hydrogenating catalyst under 50-300kg/cm<2>G hydrogen pressure at 300-500 deg.C reaction temperature and 300-2,000Nl/l hydrogen/coal tar raw material ratio so as to make 15-70wt.% denitrogenation ratio. Then the hydrogenated raw material is subjected to delayed coking to give raw pitch coke, which is carbonized by a coke oven of chamber oven type to give the objective pitch coke.

Description

[Detailed Description of the Invention] [Industrial Field of Application J] The present invention has a high carbonization yield for castings with low ash content, especially sulfur content, gas generation, and other uses.
The present invention also relates to a method for producing bulk pitch coke with large particle sizes.

[Conventional technology]

Methods for producing pitch coke include the room furnace method and the delayed coker calcite method, which is an improved version of the petroleum coke production method.

In the past, in the room furnace method, pitch coke was produced by charging hard pitch into a cot parse furnace and carbonizing it, and the lump coke in this case was also used as gas coke. However, due to the strong demand for needle coke production and the operational and environmental problems of hard pit carbonization in coke ovens, the room oven method has now been completely abolished, and all methods are now using delayed coker or coke ovens.
It has changed to the Calsaichi method. In the delayed coker/calcici process, raw pitch coke is produced from coal-based or petroleum-based raw material pitch in a delayed coker, and this raw pitch coke is calcined at 1200 to 1500°C in a calciner, or rotary kiln, to produce pitch coke. Manufacture. The true specific gravity of products manufactured using this method is 2.
．． It has a high grain size of 0 to 2.1 and has few impurities, but the particle size is small, there are many cracks, and the porosity is high. This coke is used as a raw material for aluminum, electrodes, and special carbon materials, and lumps, cracks, and porosity are relatively non-problems. However, it cannot be used for foundry or gas applications where the characteristics of lump coke are important.

Therefore, in recent years, grain size 20 is used for castings and gas generation.
In the production of lump pitch coke of ~120 m+s, the volatile content produced in a delayed coker is 7 to 1.
Generally, 0% by weight petroleum-based or coal-based raw pitch coke is used as a raw material, binder pitch, inert carbon powder, etc. are added as auxiliary materials, and the coke is carbonized mainly in a room furnace type coke oven.

However, when raw pitch coke with a volatile content of less than 10% by weight is carbonized, the raw pitch coke is carbonized in a solid state without being melted during the process, so the pitch cokes do not stick together. Binder pitch is added to bind pitch coke together.

Therefore, the product coke had a dual structure of pitch coke that was carbonized without melting and binder pitch that was melted and carbonized, and as a result, high strength could not be obtained.

The present applicant has previously devised a method of carbonizing raw pitch coke with a volatile content of 10 to 20% by weight in a delayed coker in an indoor coke oven.

In this raw pitch coke with a high volatile content, the coke itself melts during the carbonization process and becomes liquid, causing the coke to stick together.

Therefore, there is no need to add binder pitch or the like as an auxiliary raw material, and the product coke has a monolithic structure and is high in density and strength.

The higher the volatile content of raw pitch coke, the higher the fusion properties, but the carbonization yield of the product decreases accordingly.

[Problem to be solved by the invention]

In order to obtain a product with a high carbonization yield, it is better not to add binder pitch or the like, and the less volatile content of the raw pitch coke, the better. On the other hand, in order to obtain a product with high strength, the volatile content of raw pitch coke must increase the fusion properties.

An object of the present invention is to provide a method for producing pitch coke with a high carbonization yield, large particle size, high strength, and low sulfur content and ash content.

[Means to solve the problem]

The present inventors conducted extensive research to solve the above problems, and found that among the volatile components in raw pitch coke, only volatile components with a boiling point of 600°C or lower contribute to the welding of pitch coke. We have discovered that by selectively increasing the volatile components below 600°C, pitch coke with large particle size and high strength can be obtained with a high carbonization yield even from raw coke with a volatile content of less than 10% by weight. , completed the invention.

In the present invention, a coal tar-based raw material is hydrotreated in the presence of a hydrogenation catalyst so that the denitrification rate is 15% by weight or more and 70% by weight or less, and this hydrogenated raw material is subjected to delayed coking to produce raw pitch coke. A method for producing pitch coke is characterized in that the pitch coke is subjected to carbonization treatment in a room furnace type coke oven.

The present invention will be explained in detail below.

The volatile content of raw pitch coke can be divided into components with a boiling point of 600°C or lower and components with a boiling point of 600°C or higher. Components with a boiling point of 600°C or lower are mainly due to the evaporation of low-boiling components of the raw pitch coke, and components with a boiling point of 600°C or higher are mainly due to the decomposition of higher-boiling components at high temperatures.

- Considering the case where Banli pitch coke is melted in a room furnace type coke oven, the melting of raw pitch coke occurs at around 350℃, and the raw pitch coke becomes shaped, but at 450℃
If the temperature exceeds 100%, the carbonization reaction will proceed rapidly. Therefore, only volatile components with a boiling point of 600° C. or lower contribute to the fusion of pitch coke, and volatile components with a boiling point of 600° C. or higher only reduce the carbonization yield of coke.

By controlling the production conditions of the delayed coker, specifically by controlling the temperature of the coking heater, it was not possible to selectively increase only the volatile components with a boiling point of 600° C. or lower.

When a coal tar-based raw material, which is a raw material for producing raw pitch coke, is pre-hydrogenated, components having a boiling point of 600° C. or lower are selectively increased. FIG. 1 shows a weight loss curve determined by a thermobalance, with temperature on the horizontal axis and weight percent on the vertical axis, and a differential curve of the curve, for raw coke produced from pre-hydrogenated raw materials. Figure 2 shows a similar curve for raw coke made from feedstock without hydropretreatment.

As is clear from FIGS. 1 and 2, the amount of volatile matter with a boiling point of 600° C. or lower in the raw coke produced from the raw material is greatly increased by the hydrogenation pretreatment.

Figure 3 shows the volatile content (%) on the horizontal axis and the coke fusion rate (%) on the vertical axis, and shows the case when pre-hydrogenation treatment is performed.
A fusion rate curve is shown comparing the fusion rate when no fusion was performed.

As is clear from this figure, even if the volatile content is the same, the fusion rate of the produced raw coke increases by pre-hydrogenating the raw material.

As a result, raw coke produced by directly subjecting raw materials to a delayed coker and having a volatile content of less than 10%, which did not form lump coke even after carbonization treatment in an indoor coke oven, was found to be If coke is pre-hydrogenated, it will form lump coke, and coke pre-hydrogenated will have higher mechanical strength when compared with product coke made from raw coke with the same volatile content. found.

Coal tar-based raw materials include coal tar produced when coal is carbonized, high boiling point tar oil and tar pitch separated from coal tar, and preferably tar pitch. As the tar pitch, a soft pitch with a softening point of 70° C. or lower is used.

Alternatively, soft pitch mixed with coal tar or high boiling point tar oil may be used.

In the present invention, the coal tar-based raw material is hydrorefined in the presence of a hydrogenation catalyst until the denitrification rate is 15% by weight or more and 70% by weight or less. As mentioned above, the main purpose of this is to increase the components with a boiling point of 600°C or less, but coal tar-based raw materials have a sulfur content of 0.2 to 1% by weight and a nitrogen content of 1 to 1% by weight.
2% by weight, and it is undesirable for these components to remain in lump coke in any applications such as foundry applications and gas generation applications.

However, advantageously, when the hydrogenation treatment of the present invention is performed to increase the components having a boiling point of 600° C. or lower, desulfurization and denitrification reactions also occur at the same time. This denitrification reaction is utilized to measure the degree of hydrogenation in the present invention. The lower the sulfur content of coke for foundries and gas generation, the better. The present invention also exhibits the effect of lowering the sulfur content.

Hydrorefining is carried out under hydrogen pressure and in the presence of a hydrogenation catalyst.

Hydrogenation conditions are, for example, 50 to 300 k in the case of batch reaction.
hydrogen pressure of g/cjG, reaction temperature of 300-500°C, 3
00~200ONg/j! This is the hydrogen/coal tar raw material ratio. The reaction time varies depending on conditions such as the FIi of the catalyst, the amount thereof, and the reaction temperature, but in any case, the reaction is carried out until the denitrification rate specified above is achieved.

In addition, the reaction conditions in the case of continuous reaction are the same as in the case of batch reaction, such as catalyst, temperature, pressure, etc., but the reaction time, that is, the contact time, is 1 O61 to 2 h'' as liquid-based space velocity, preferably 0.5 ~1,5hr-l
is appropriate.

The hydrorefined coal tar raw material is coked into raw pitch coke. That is, in a delayed coker under pressure (e.g. 1 to 10 kg/cdG)
Carbonization is performed at 0°C to obtain raw pitch coke.

The volatile content of raw pitch coke is mainly adjusted by changing the heating temperature conditions of the raw materials. Raw pitch coke is
Then, in a room furnace type coke oven, the temperature is 1000-1300℃.
to obtain pitch coke.

〔Example〕

EXAMPLES The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples in any way.

(Example 1) Using a fixed bed continuous hydrogenation experimental apparatus, the reaction temperature was 400°C,
Coal tar pitch was hydrogenated using a Ni-Mo/alumina hydrogenation catalyst commercially available as a hydrodesulfurization catalyst under a reaction pressure of 150 kg/cjG and a liquid hourly space velocity of 10.75 hr. The denitrification rate was 61% by weight. After expelling the low boiling point components of this hydrogenated coal tar pitch and adjusting the softening point to 44° C., raw coke was obtained in a small delayed coker.

The volatile content of the raw coke was 8.3% by weight.

This raw pitch coke was crushed to 95% of 31111 or less, and 1/4 was charged into a test coke oven.
It was carbonized at ℃ for about 24 hours.

Table 1 shows the physical properties and yield of the product.

(Example 2) Using a fixed bed continuous hydrogenation experimental device, the reaction temperature was 400°C,
Coal tar pitch was hydrogenated using a Ni-Mo/alumina hydrogenation catalyst commercially available as a hydrodesulfurization catalyst at a reaction pressure of 150 kg/anG and a liquid hourly space velocity of 1 O, 75 hr. The denitrification rate was 60% by weight.

After expelling the low boiling point components of this hydrogenated coal tar pitch and adjusting the softening point to 42° C., raw pitch coke was obtained in a small delayed coker. The volatile content of the raw pitch coke was 12.2% by weight.

1 raw pitch coke crushed to 95% for 3 questions or less
/4 was charged into a test coke oven and carbonized at 1100°C for about 24 hours. Table 1 shows the physical properties and yield of the product.

(Comparative Example 1) Coal tar pitch with a softening point of 41° C. was directly charged into a small delayed coker to obtain raw pitch coke. The volatile content of the raw pitch coke was 8.5% by weight.

This raw pitch coke was crushed to 95% and 1/4 of it was charged into a test coke oven and heated to 1100℃ for about 2 hours.
It was carbonized for 4 hours. Regarding product physical properties and yield,
Shown in Table 1.

(Comparative Example 2) Coal tar pitch with a softening point of 41° C. was directly charged into a small delayed coker to obtain raw pitch coke. The volatile content of the raw pitch coke was 12.9ffi%. This raw pitch coke was pulverized to 95% or less, and 1/4 was charged into a test coke oven and heated to 1100℃ for about 24 hours.
It was carbonized for hours.

Table 1 shows the physical properties and yield of the product.

〔Effect of the invention〕

Since the pitch coke produced by the method of the present invention is hydrogenated prior to coke formation, there are many components with boiling points of 600°C or less in the volatile matter of the raw coke. It is possible to obtain high-strength pitch coke with large particle size and high carbonization yield.

Hydrotreating reduces the sulfur and nitrogen content in the raw material, making it possible to produce pitch coke for foundries and gas generation with low sulfur, nitrogen, and ash contents.

This is an extremely excellent method for producing large pitch coke for foundries, etc., using a delayed coker.

FIG. 1 shows a weight loss curve and its differential curve corresponding to FIG.

Figure 3 shows the volatile content (%) on the horizontal axis and the fusion rate (%) on the vertical axis. The raw coke obtained by hydrogenating the raw material and the raw coke without hydrogenating the raw material are fused even with the same volatile content. This figure shows that there is a large difference in the rates.

Claims (1)

[Claims] Denitrification rate of coal tar-based raw materials in the presence of a hydrogenation catalyst: 1
It is characterized by hydrogenating to a content of 5% by weight or more and 70% by weight or less, delay coking of this hydrogenated raw material to obtain raw pitch coke, and carbonizing the raw pitch coke in a room furnace type coke oven. A method for producing pitch coke.