JPH05239466A - Preparation of needle coke - Google Patents

Abstract

PURPOSE:To provide a process for preparing needle coke of petroleum origin having a low thermal expansion coefficient. CONSTITUTION:The objective process for preparing needle coke of petroleum origin comprises removing ash from a residual oil obtd. through fluid catalytic cracking(FCC) or a hydrocarbon substance mainly comprising the same to an ash content of at most 0.01%, and coking the remaining oil or substance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing petroleum needle coke having a low coefficient of thermal expansion.

[0002]

2. Description of the Related Art In recent years, with the severer conditions for using electrodes,
Needle coke with a low coefficient of thermal expansion has become popular. Under these circumstances, by removing the quinoline insoluble matter in coal tar and coal tar pitch, it became possible to produce needle coke that exceeds the thermal expansion coefficient of conventional petroleum needle coke.

Therefore, various attempts have been made to use a petroleum-based raw material to lower the thermal expansion coefficient of coal-based needle coke, but it has not been practically put into practical use and is still a commercially available petroleum-based needle. Currently, no coke outperforms coal-based needle coke. For example, in fluid contact residue oil (FCC) used as a raw material for petroleum-based needle coke, 0.02 to 0.
The ash content of about 03% (200 to 300 ppm) or more, that is, FCCC catalyst (silica-alumina system etc.) is contained.

Therefore, conventionally, attention has been paid to the pretreatment such as heat treatment, and the reduction of thermal expansion coefficient has been studied. However, the conventional method has a limit in reducing the thermal expansion coefficient, and the petroleum-based needle coke has a higher thermal expansion coefficient than the coal-based needle coke under the present circumstances.

[0005]

SUMMARY OF THE INVENTION The present invention uses a fluid catalytic cracking (FCC) residual oil or a hydrocarbon mainly containing the same, and has a low coefficient of thermal expansion and is easily and inexpensively high-quality petroleum-based needle coke. The present invention provides a method of manufacturing the same.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the inventors of the present invention have surprisingly found that the catalyst for FCC treatment has a harmful effect on the coefficient of thermal expansion of FCC residual oil. The inventors have found that they can be easily removed by electrostatically agglomerating them, and have reached the present invention. Specifically, as an example, by passing FCC residual oil between electrode plates applied with a voltage, the catalyst fine particles in the FCC residual oil become charged and agglomerated, become huge, and are removed to remove FC
The inventors have found that needle coke having a low coefficient of thermal expansion is obtained by using C residual oil as a raw material, and completed the present invention.

That is, the gist of the present invention is that the ash content of FCC residual oil or a hydrocarbon substance composed mainly of FCC residual oil is 0.01%.
It is a method for producing petroleum-based needle coke, which comprises coking after removal to (100 ppm) or less.
The FCC residual oil used in the present invention is an oil by-produced when a petroleum fraction such as light oil is catalytically cracked by a granular catalyst to produce gasoline, LPG and the like.

Further, the hydrocarbon substance mainly composed of FCC residual oil means that FCC residual oil contains pyrolysis oil, atmospheric residual oil, reduced pressure residual oil, coal tar, coal tar pitch, and other organic substances with respect to FCC residual oil. ~ 70 wt% refers to a mixture. In the method of the present invention, the ash content of the FCC residual oil or the hydrocarbon substance mainly composed of the FCC residual oil is removed to 0.01% or less. Removal is generally performed by filtration, centrifugation or electrostatic coagulation.

First, when removing by filtration, 100
FCC residual oil heated to a temperature of ℃ to 300 ℃, for example, at a pressure of about 1 to 5 kg / cm ² G, preferably 3μ
Filtration is usually performed using the following membrane filters. When the ash is removed by centrifugation, it is usually preferably 300 ° C or lower, and preferably 700 ° C or lower.
Perform with a centrifugal force of 0 G or more. With a centrifugal force of less than 7,000 G, the efficiency of removing the agglomerated catalyst fine particles decreases, and
Temperatures above 10 are not preferable in terms of durability of the centrifuge.

In the present invention, there are various conditions for applying a voltage to the catalyst fine particles in the FCC residual oil to charge them, but as an example, two electrode plates having a sufficient surface area (combined in multiple layers in some cases) may be used. 1mm to 100
A voltage of 1 kV to 100 kV, preferably 5 to 30 kV is applied at a distance of 0 mm. The FCC residual oil heated to a temperature of preferably 300 ° C. or lower is passed between the electrode plates thus applied with a voltage. In order to agglomerate and remove the catalyst fine particles in the FCC residual oil, it is generally preferable to increase the temperature and lower the viscosity of the FCC residual oil because the efficiency is good.
If the temperature exceeds 1, the internal disturbance is caused in the carbonaceous raw material, which is not preferable. At this time, a light oil may be added as a method of decreasing the viscosity. In this way, the FCC residual oil in which the catalyst fine particles are electrostatically aggregated is removed by the centrifugal separation method at a temperature of preferably 300 ° C. or lower, preferably 7,000 G or more.

The FCC residual oil obtained by removing the catalyst fine particles obtained as described above (ash content is preferably 0.01% or less,
(More preferably 0.005% or less, most preferably 0.002% or less) or a hydrocarbon substance mainly containing the same is charged into a delayed coker, coke at 450 to 500 ° C., then a rotary kiln, a rotary hearth furnace or Needle coke can be obtained by calcining at 1200 to 1500 ° C. using a shaft furnace or the like.

At this time, various carbonaceous raw materials may be separately subjected to the above treatment and blended. In the method of the present invention, the ash content is set to 0.01% or less as described above.
Coal-based heavy oil that does not substantially contain quinoline-insoluble matter may be mixed with C residual oil or the like in an amount of about 5 to 70 wt% to obtain a coking raw material. Coal tar heavy oils are ordinary coal tar produced as a by-product during coke production and coal tar pitch having a softening point of 100 ° C. or lower. A known method can be used to remove the quinoline-insoluble matter from the coal tar heavy oil.

[0013]

[Examples] Specific examples will be described below. The coefficient of thermal expansion was calculated by blending the calcined coke in particle size, adding 2% of iron oxide as an inhibitor, and mixing with a kneader for 1 hour.
After molding and manufacturing a lab electrode, it was calcined at 1000 ° C., graphitized at 2800 ° C., and measured.

Example 1 FCC residual oil (ash content 0.024%) was heated to 150 ° C. and then passed through a 0.5 μm membrane filter at a pressure of 4 kg / cm ² G to remove ash content. The obtained FCC
Residual oil in autoclave at 500 ° C for 24 hours, pressure 3k
It was caulked at g / cm ² G and calcined at 1400 ° C.
The results are shown in Table 1.

Example 2 FCC residual oil (ash content 0.024%) was heated to 100 ° C., and then treated with a self-discharging separation plate type centrifuge having a centrifugal force of 10000 G to remove ash content. The FCC residual oil obtained was coked in the same manner as in Example 1. The results are shown in Table 1.

Example 3 FCC residual oil (ash content 0.024%) was added at 61 / min. At a flow rate of 10 kV, it was passed between the electrode plates, and subsequently treated with a self-discharging separator plate type centrifugal separator having a centrifugal force of 7,000 G to remove ash. The FCC residual oil obtained was used in Example 1.
Coked in the same way as. The results are shown in Table 1.

Example 4 FCC residual oil from which ash was removed by the same method as in Example 1, coal tar pitch having a softening point of 40 ° C. and a solvent having a solubility index of 70 (mixture of kerosene and aromatic oil) were mixed ( Mixing ratio 1: 0.6) Coal tar pitch obtained by removing the quinoline insoluble matter by static separation (temperature 250 ° C.) and then distilling the solvent was mixed in the ratio shown in Table 2 and coke was carried out in the same manner as in Example 1. Turned into The results are shown in Table 2.

Comparative Example 1 FCC residual oil without ash removal (ash content 0.024
%) Was coked in the same manner as in Example 1. Comparative Example 2 Coal tar pitch from which quinoline insoluble matter was removed by the same method as in Example 4 was coked by the same method as in Example 1.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

According to the present invention, needle coke having a low coefficient of thermal expansion can be produced from FCC residual oil.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoichi Ohashi, No. 1 Kyushu Town, Sakaide City, Kagawa Prefecture, Sakaide Factory, Mitsubishi Chemical Co., Ltd. Sakaide Factory (72) Inventor Yuji Yamamura, No. 1 Kyushu Town, Sakaide City, Kagawa Mitsubishi Chemical Co., Ltd. Sakaide Factory

Claims (5)

[Claims] 1. A method for producing needle coke, which comprises coking after removing the ash content of a heavy oil obtained by fluid catalytic cracking of petroleum or a hydrocarbon substance mainly composed of the heavy oil to 0.01% or less. 2. A coal tar-based heavy oil substantially free of quinoline-insoluble matter after removing ash of a heavy oil obtained by fluid catalytic cracking of petroleum or a hydrocarbon substance mainly composed of the same to 0.01% or less. A method for producing needle coke, which comprises mixing with coke to form coke. 3. The method according to claim 1, wherein the ash removal is performed by filtration. 4. The ash removal is carried out by centrifugation.
Or the method described in 2. 5. The ash removal is performed by electrostatic coagulation.
Or the method described in 2.