JPS6057477B2 - Method for manufacturing petroleum-based pituti - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing petroleum pitch.

More specifically, the present invention relates to a method for producing petroleum pitch using a heavy residual oil by-produced during the production of olefins by steam cracking of petroleum hydrocarbons as a raw material oil. Olefins such as ethylene and propylene are usually produced by steam cracking or thermal cracking of petroleum hydrocarbons such as naphtha and kerosene. In recent years, with the expansion of ethylene production facilities and the increasing weight of raw petroleum hydrocarbons, the amount of heavy residual oil produced as a by-product during decomposition has increased significantly. However, this heavy residual oil is only partially used as a raw material for carbon black.
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Therefore, in recent years, converting this heavy residual oil into products with higher added value has become an urgent issue in the technical field.
However, various studies are being conducted on the development of high value-added uses of this heavy residual oil, such as binder pitch and coke for use in carbon electrodes, refractory bricks, etc., taking advantage of its aromatic property. However, in order to thermally reform these heavy oils and obtain binder pitch and coke, there are problems that need to be solved such as coking trouble and softening point control. Since petroleum-based pitches are not very satisfactory in terms of binder performance, they have not yet been put into practical use except in special cases. In other words, when thermally reforming heavy oil, a combination of a heating tube and a thermal reforming reactor (soaker) is more realistic, but the heat transfer coefficient decreases due to carbon deposition within the heating tube. Furthermore, continuous operation for long periods of time is difficult due to blockage, and it is almost impossible to operate on a commercial basis due to obstacles such as carbon deposits on the gas-liquid interface within the saw force.
On the other hand, since the oil crisis, resource and energy conservation has been called for, and further improvements in binder performance are desired.

In other words, in the steel industry, coking coal for coke production is expected to be in short supply, quality will decline, and costs will increase, reflecting global political and economic conditions. is being attempted. Furthermore, the usage conditions for refractory bricks for steel are severe, and improvements in the binder performance and the sowing layer are required. The present invention provides an innovative reforming technology that solves these problems all at once.

That is, the present inventors used heavy oil with a boiling point of 150° C. or higher obtained by steam cracking of petroleum hydrocarbons as a raw material (hereinafter referred to as raw material oil) in a method for producing petroleum pitch, in which a predetermined amount of the raw material oil was added to the raw material oil. It was discovered that pitch superior to coal tar pitch could be obtained by adding carbon black and then heat-treating under pressure, thereby completing the present invention. Generally, heavy oil is heated to 360'C.
When kept at a higher temperature than above, covalent bonds with low binding energy are first cleaved by thermal decomposition, and reactions such as hydrogen abstraction, dehydrogenation, recombination, and cyclization proceed with the generated free radicals, and the separated products are At the same time as it is stabilized, some of it further decomposes into lower molecules and polymerizes to turn into carbonaceous substances, causing so-called coking troubles. To prevent this caulking trouble,
For example, a method is known in which steam stripping is always performed without leaving cracked oil in the liquid phase. Further, Japanese Patent Publication No. 35681/1983 discloses a method of adding carbonaceous solid fine particles having a particle size of 50 to 1000 μm to atmospheric residual oil or vacuum distillation residual oil. These carbonaceous solid particles selectively adsorb coke components, grow larger, and are added to the coke components. It is also disclosed that the carbonaceous solid fine particles exhibit a catalytic effect on coking, since the relative coke yield increases considerably when the carbonaceous solid particles are not used. On the other hand, JP-A-50-112
No. 417 and Japanese Patent Application Laid-open No. 112418/1983, carbon bra was applied to coal tar pitch. A modification of pitch by adding sulfur is disclosed. That is, when carbon black with an average particle size of 50 to 607 nμ is added to coal tar, the carbon black is uniformly dispersed in the pitch, and when heat treated, it behaves similarly to free carbon and exhibits optical anisotropy and small spherical properties. It is disclosed that the characteristic values of pitch, which are typified by the softening point, fixed carbon, benzene-insoluble content, and quinoline-insoluble content, increase when the pitch adheres to the surrounding area. In addition, Japanese Patent Publication No. 45-2294 discloses a method for producing coal tar pitch, the gist of which is that carbon material is added to so-called medium pitch and the characteristic values are increased by heating it under normal pressure. This is related to the modification of pitch.

The present invention relates to a method for producing petroleum pitch by adding carbon black to heavy oil with a boiling point of 150° C. or higher obtained by steam cracking of petroleum hydrocarbons and heat-treating the mixture under pressure. The pitch obtained by the above method is a high quality pitch superior to coal tar pitch.

Although the reason why the binder performance of pitch is improved by adding carbon black to the raw material oil of the present invention is not clear, the following has become clear from various experiments and studies conducted by the present inventors. When carbon black is added to the raw material oil used in the present invention and heat treatment is performed under normal pressure, the softening point of the pitch increases significantly as shown in Table 1 (Experiment 3) below, making it unusable for practical use. .

On the other hand, in the case of coal tar pitch,
As described in Phase No. 5-229, etc., even when heat treated under normal pressure, the increase in the softening point is very small, which is clearly different from the present invention. This is due to the difference in raw materials, that is, the boiling point of 150
This is due to the difference in raw materials between heavy oil at temperatures above ℃ and coal tar pitch. That is, even if the raw material oil of the present invention and the coal tar pitch are treated under the same conditions, they will not have the same performance, and they cannot be treated as the same. This is also supported by the following facts. That is, when observing the pitch obtained by the method of the present invention using a polarizing microscope, it was found that carbon black did not exhibit any catalytic action for coking;
It was confirmed that the behavior is different from that of free carp in coal tar pitch. In order to examine the reason for this in more detail, we forcibly precipitated coking in the reactor under harsh conditions and compared it with the precipitated material without the addition of carbon black. On the other hand, when carbon black is added, fine spherulites are uniformly dispersed in the pitch matrix, and carbon It was confirmed that no coke was generated around the black. This fact is also supported by the pitch characteristic values. When carbon black is added to coal tar pitch and heat treated, the characteristic values of fixed carbon, benzene-insoluble matter, and quinoline-insoluble matter increase, but carbon black is added to the raw material oil used in the present invention and heated under pressure. When treated, the yield of coke, which is represented by fixed carbon, benzene-insoluble matter, etc., decreases compared to the case where no carbon black is added, as shown in Table 1 (Experiments 1 and 2) below. The reason why the coke yield decreases by the method of the present invention is presumed to be that coking is suppressed, which prevents the high molecular weight components in the feedstock oil from further polycondensing, and at the same time increases the intermediate molecular weight components. be done. Also,
As is clear from these findings, the carbon black used in the present invention has a catalytic action, which is completely different from the carbonaceous solid fine particles with a particle size of 50 to 1000 μm described in Japanese Patent Publication No. 52-35681. Then it will be judged. The present invention uses a heavy residual oil with a boiling point of 150'C or more obtained as a by-product when producing olefins by steam cracking petroleum hydrocarbons as a raw material.

Here, light hydrocarbons such as naphtha and kerosene are usually used as petroleum hydrocarbons, and steam cracking
It is usually carried out at a temperature of 00°C. The heavy residual oil used in the present invention has a boiling point of 150° C. or higher, and preferably has a boiling point of 200° C. or higher. As the carbon black used in the present invention, one having a particle size of 10 to 1007 TL, μ is particularly preferably used.

Further, the amount of carphone black added is 0.5~. 20%, preferably 1-15%. If the amount added is too small, the effect of the present invention is not achieved, and if the amount added is too large, the rate of increase in the effect of improving binder performance is not only small, but also the fluidity of the pitch is reduced, which is not preferable. In the present invention, carbon black is added to raw material oil and heat treated under pressure.

Pressure range is 2-20kgIcd-G1 preferably 5-1
5k91cIL-G, temperature range is 380-460
0C, and the heating time is in the range of 1 to 1 hour, preferably 3 to 5 hours. When the petroleum pitch obtained by the method of the present invention is used as a binder for carbon molded bodies, 1
Practical performance such as binder carbonization rate and compressive strength when fired at 000 to 1200°C is extremely excellent. In particular, by using the method of the present invention, binder carbonization rate is 77 to 85.
% can be obtained.

The binder carbonization rate of the binder using petroleum pitch obtained by the conventional method is at most 75%, and it is completely unexpected from the conventional method that the binder carbonization rate is 77% or more by the method of the present invention. I must say that this is a truly astonishing fact. The binder carbonization rate as used in the present invention is measured by the following method. (1) Mix the sample pitch ω1y and the aggregate (petroleum coke) ω2y at a temperature 50 to 100'C higher than the softening point of the sample pitch, (11) Mold (40T!r!nφ x 40m) !n)
and compression molded for 1 minute under a load of 2.5 tons at a kneading temperature to obtain a test piece.

(1i1) This test piece is placed in an electric furnace under a nitrogen atmosphere and fired under the following conditions.

Heating rate: 200 C1day (from room temperature to 600'C)
6000C1day (600~1200'C) 1200℃ holding time 2 hours (Iv) The pitch obtained by the method of the present invention is to measure the weight (ω3y) of the fired test piece and calculate the Baingu carbonization rate from the following formula. carbon electrode,
It is effectively applied as a binder pitch used in the molding of refractory bricks, etc.

The present invention will be specifically described below with reference to Examples, but the present invention is not limited thereto.

Experiment 1 500 mL of heavy residual oil (its properties are shown in Table 2) produced as a by-product when steam decomposing naphtha was collected in an autoclave with an internal volume of 1 f and equipped with a stirrer, and heated at 400°C110k91d-
It was maintained under the conditions of G for 3 hours.

The obtained heat-treated oil was subjected to simple distillation under the conditions of 220'Cl4TWlHg to obtain pitch. The properties of this pitch are shown in Table 1. Experiment 2 Add 3 ml of thermal black (MT) as carbon black to 500 ml of the heavy residual oil used in Experiment 1.
Pitch was obtained in the same manner as in Experiment 1 except that % by weight was added.

The properties of this pitch are shown in Table 1. Experiment 3 3% by weight of thermal black (MT) was added as carbon black to 500 TnL of the heavy residual oil used in Experiment 1, and the mixture was held at 400° C. for 1 hour under normal pressure.

The obtained heat-treated oil was subjected to simple distillation under the conditions of 220° C. and 47 nmHg to obtain pitch. The properties of this pitch are shown in Table 1. Example 1 Heavy residual oil (its properties are shown in Table 2) produced as a by-product when steam cracking naphtha was used as a feedstock oil, and the internal volume was 1e (7).
500 ml was collected in an autoclave equipped with a stirrer, and furnace black (with an average particle size of 75 mμ and a pH of 7.7) was added to it.
#55) After adding 5y, heat with a band heater,
400℃, 10k91cT1- while removing volatiles.
It was kept under G conditions for 3 hours.

The resulting heat treatment was performed at 220'Cl4T! Pitch was obtained by simple distillation under RInHg conditions. Table 3 shows the properties of this pitch.
It was shown to. Next, the pitch of 13.4y was mixed with 65.6y of aggregate (petroleum coke) and molded (400mm diameter x 40mm).
A test carbon electrode was prepared using wn), and this test piece was placed in an electric furnace under a nitrogen atmosphere and fired under the following conditions. Heating rate: 2000CIc1ay (from room temperature to 600℃)
600'Clday (600~1200℃) 120
0° C. holding time: 2 hours After firing, the binder carbonization rate of the test piece was 82%, and the counter pressure was 320k91cJ.

Comparative Example 1 Pitch was obtained in the same manner as in Example 1 except that furnace black was not added.

The properties of this pitch are shown in Table 3. Next, a test carbon electrode was prepared and fired using the pitch in the same manner as in Example 1. The binder of the test piece has a carbonization rate of 75% and a resistive pressure of 270k.
It was g1d. Example 2 In Example 1, except that Furnace Black (MA-100) 25y with an average particle size of 22 m, μ, and PH of 3.0 was used instead of Furnace Black (#55) 5f. The binder carbonization rate of the test carbon electrode obtained in the same manner as in Example 1 was 85%, and the counter pressure was 32.
It was 0 kgIcT1.

Example 3 500 ml of the raw oil used in Example 1 and the furnace black 5y used in Example 2 were collected in an autoclave with an internal volume of 11 and equipped with a stirrer, and heated at 430° C. and 10 kg IcIt.
・Hold for 1 hour under the conditions of G to obtain heat treated oil, then 2
Pitch was obtained by simple distillation at 20° C. and 47 wtHg.

The properties of this pitch are shown in Table 4. Then this pitch 7
y and aggregate (magnesia clinker 70y and fine powder 70y
y) were mixed together, molded in a mold (40 wrmφ x 4 m), and then baked at 350° C. for 4 hours. This fired brick test piece was placed in an electric furnace under a nitrogen atmosphere, heated at a rate of 10°C/min, and held at 1000'C for 2 hours. The residual carbon content of the bricks after firing is 48.9%, and the compressive strength is 200k91.
cI, which was significantly improved compared to Comparative Example 2. Comparative Example 2 A fired brick was obtained in the same manner as in Example 3, except that furnace black was not added.

The residual coal content was 46.8%, and the compressive strength was 115k91cT1. Example 4 In Example 3, instead of the furnace black, an average particle size of 30rrL. A fired brick was obtained in the same manner as in Example 3, except that a furnace black (#30) 25y having μ and PH of 8.0 was used.

Claims (1)

[Claims] 1. Boiling point obtained by steam decomposition of petroleum hydrocarbons 1
After adding carbon black to heavy oil at 50℃ or higher,
A method for producing petroleum pitch having a binder carbonization rate of 77 to 85%, the method comprising heat treatment under a pressure of 2 to 20 kg/cm^2.G. 2 The heat treatment is performed at 380 to 460°C and for 15 minutes to 1
Claim 1 carried out under conditions of 0 hours.
Manufacturing method described in section. 3. The manufacturing method according to claim 1 or 2, further comprising the step of separating the produced pitch by simple distillation after the heat treatment.