JPH0254395B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing pitch having excellent performance as a raw material for producing high strength, high modulus carbon fiber. More specifically, distillation residual oil with a boiling point of 400°C or higher, which is produced as a by-product from a fluid catalytic cracker using petroleum as feedstock, and aromatic heavy oil mainly consisting of aromatic compounds with four or more rings and their partially hydrogenated products. A thermal reforming reaction is carried out using a mixture of quality oils as raw materials, and after that, insoluble substances are separated and removed from the reaction product and then distilled under reduced pressure to obtain pitch. The present invention relates to a method for producing a pitch for carbon fiber raw material with excellent performance, which is characterized by skillfully utilizing a thermal reforming reaction in the coexistence of these partial hydrides. Carbon fiber (graphitized fibers are also collectively included in carbon fiber) is lightweight, has high strength,
It has the characteristics of high elastic modulus, heat resistance, chemical resistance, and electrical conductivity, and is said to be one of the promising industrial materials. Because of its particularly high specific strength (strength per unit weight) and specific modulus (modulus of elasticity per unit weight), it is used in the form of composite materials with synthetic resins, metals, or carbon, and is used in aerospace and automobile applications. It is expected that it will be used in large quantities in the future for industrial and mechanical materials.
There are various processes for producing carbon fiber, but an industrial method for producing carbon fiber directly from a substance that has already completely turned into carbon has not yet been developed, so the current process uses organic matter as a precursor. A method is used in which precursor organic fibers obtained by first spinning are subjected to various treatments, including carbonization, while maintaining the fiber shape, to finally obtain fibers made mostly of carbon. Carbon fibers are classified into lignin-based, cellulose-based, polyacrylonitrile-based, rayon-based, pitch-based, etc. depending on the precursor organic material from which they are made, but their properties vary greatly depending on the precursor organic material. It is generally known that the properties of the final product of carbon materials are largely controlled by differences in the properties of precursor organic substances, and carbon fibers are a typical example of this. Pitch-based carbon fibers are characterized by the fact that the precursor pitch, which is the raw material, is cheaper than polyacrylonitrile. It is a general term for substances that are solid and turn into a viscous oil when heated, and does not refer to a specific substance, but exists in a variety of properties. Therefore, if a method for producing raw material pitch for carbon fibers with high strength and high modulus of elasticity could be developed by skillfully controlling the properties of pitch, it would be of extremely great industrial value. Currently, the method for producing high-strength, high-modulus carbon fibers using pitches as raw materials is to carbonize and/or
Alternatively, a method using graphitization and a method using optically anisotropic pitch containing a large amount of mesophase as a raw material have been proposed. For example, in Tokuko Sho 47-10254, 550 ~
850℃ and/or 1350-2800 during graphitization treatment
A method of applying stress in the temperature range of 0.degree. C. is disclosed. However, it is difficult to carry out such a method on an industrial production scale because a complicated device is required to apply stress to the fiber during carbonization or graphitization treatment, and the effect is not so great. In addition, Japanese Patent Publications No. 54-1810 and No. 55-37611 disclose a method for manufacturing carbon fiber using pitch containing a large amount of mesophase as a raw material, and petroleum pitch, coal tar pitch, and acenaphthylene pitch are used as raw materials. It is considered desirable. However, it is difficult to produce pitches with the same properties suitable for carbon fiber production only by heat treatment of such a wide range of raw materials, and in this application, detailed modification operations of each raw material are required. has not been disclosed. Furthermore, JP-A-57-88016 discloses a method for producing pitch, a raw material for producing carbon fiber, using as a starting material a tar-like substance produced by the catalytic cracking of petroleum or a tar-like substance produced by the thermal decomposition of naphtha. ing. In this method, after heat-treating the starting material, mesophase is concentrated and separated and recovered by gravity sedimentation to obtain mesophase-containing pitch.
The mesophase-containing pitch is further heat-treated in the next step to produce raw material pitch for carbon fiber production. This indicates that a pitch suitable for producing carbon fibers cannot be produced by simple heat treatment of the two tar-like substances mentioned above. In general, mesophases are condensed polycyclic aromatic molecules produced by thermal decomposition reactions and polycondensation reactions in the so-called initial carbonization process of heat-treating heavy oils, which are arranged mainly by van der Waals forces and form a certain structure. Refers to a liquid crystal state that exhibits directionality, and refers to the meso phase, which is the process in which heavy oil in the liquid phase changes to carbide in the solid phase. Mesophase was once defined as being equivalent to quinoline insoluble matter, but recent research has revealed that mesophase and quinoline insoluble matter are not equivalent. Furthermore, the part that shows optical anisotropy under a polarizing microscope also varies greatly depending on the observation temperature and sample preparation method, so it can also be said that this is not equivalent to mesophase. Therefore, it is no exaggeration to say that there is currently no perfect method for measuring the amount of mesophase. A pitch suitable for manufacturing carbon fibers, particularly high strength, high modulus carbon fibers, requires a large number of properties. First, during the spinning process, diameter 5~
It is necessary to be able to spin fibers of 15μ at high speed and to have fewer yarn breakages. Furthermore, in order to prevent the fibers from fusing after spinning and to perform the subsequent infusibility process well, it is necessary to be able to spin the fibers in a temperature range of 300 to 400°C. Furthermore, it is necessary that the strength of the pitch fiber after spinning is high. In addition, in the carbonization and graphitization steps, it is necessary that the arrangement of the hexagonal network planes of carbon be well developed and the graphitization properties should be good. In general, shield oils contain many types of components such as hydrocarbons, sulfur compounds, nitrogen compounds, oxygen compounds, and organometallic compounds, and these components have a wide range of molecular weight distribution and complex structures. There are many.
Therefore, the thermal reactivity of each component differs greatly, and when such heavy oils are subjected to heat treatment, the product product also becomes a mixture of components with widely different properties. Therefore, even when producing raw material pitch for carbon fiber production by heat treating heavy oil, some components may not have properties suitable for the raw material pitch if the heavy oil is simply heat treated. A large amount of components with inappropriate properties are also produced even if they are used. In the above-mentioned Japanese Patent Application Laid-Open No. 57-88016, no special measures were taken for the thermal reforming method, so the yield of components having properties desirable as raw material pitch was low. Therefore, a complicated process is required in which the lower layer of pitch is separated from the thermally reformed product by gravity sedimentation and then subjected to heat treatment. For the purpose of suppressing the reaction of components that have high thermal reactivity and undergo excessive polymerization, a method is disclosed in which a reaction is performed under pressure with hydrogen or a reaction in the presence of a solvent having hydrogen donating properties. For example, JP-A No. 57-168989, No. 57-
168990 and 58-18419, heavy oil with a boiling point of 200℃ or higher obtained when petroleum is subjected to fluid catalytic cracking and/or heavy oil with a boiling point of 200℃ or higher obtained when petroleum is steam cracked is hydrogenated. Heat treatment is performed under pressure, and if necessary, after removing light components by distillation, the reaction temperature is 340-450℃.
A method is disclosed for producing a raw material pitch for producing carbon fibers by heat-treating the material by passing an inert gas through it at room temperature or under reduced pressure to form a mesophase. Also, JP-A No. 57-16897, No. 57-168988, No. 57-
170990, 57-179285, 57-179286, 57-
179287, 57-179288, and 58-18420 include heavy oil with a boiling point of 200℃ or higher obtained when petroleum is subjected to fluid catalytic cracking and/or heavy oil with a boiling point of 200℃ or higher obtained when petroleum is steam cracked. For heavy oil of
Among the nuclear hydrides of 2- or 3-ring aromatic hydrocarbons, or the fractions produced when heat-treating these raw material pitches, or the fractions produced during the step of preparing raw material pitches by heat treatment. Hydrogenated oil with a nuclear hydrogenation rate of 10 to 70% obtained by hydrogenating fractions with a boiling point range of 160 to 400°C is added, and this is heated at a reaction temperature of 370 to 480°C and a pressure of 2 to 50 Kg/cm ² G. After that, if necessary, light components are removed by operations such as distillation, and then the raw material pitch is heated at a reaction temperature of 340 to 450°C by bubbling inert gas under normal pressure or reduced pressure. A method for producing a raw material pitch for carbon fiber production by converting the carbon into a mesophase is disclosed. The main purpose of these methods is to suppress the formation of high molecular weight components during the heat treatment stage by the action of hydrogen under pressure or donating hydrogen of nuclear hydrides. Although such a method can be said to be an improved method compared to the conventional simple heat treatment method, it has the disadvantage that the progress of the thermal reforming reaction is delayed. In addition, the nuclear hydrides of 2- or 3-ring aromatic hydrocarbons used in this method and the hydrogenated oils obtained by the various methods described above are not suitable as hydrogen-donating substances in terms of boiling point range and composition. These substances themselves are extremely unlikely to form a pitch. Therefore, the raw materials modified by various hydrogenation methods in the first stage are treated at a reaction temperature of 340 to 450°C and a reaction time of 1 to 50 °C in the second stage.
This process produces mesophases. In this way, the present method involves a two-stage reforming process. In addition, JP-A-58-41914 and JP-A-58-41915 state that pitches with an aromatic index of 0.6 or higher (specifically, coal-based coal depolymerized products, coal tar pitch, and petroleum-based ethylene bottom oils are preferable). ) is hydrogenated in a highly hydrogen-donating hydrocarbon solvent, the catalyst and insoluble solids are removed, and the hydrocarbon solvent is recovered. The resulting hydrogenated pitch is heat-treated under reduced pressure to produce carbon fibers. A method of producing a raw material pitch for manufacturing is disclosed. In this method, the heat treatment conditions under reduced pressure are a reaction temperature of 480℃ or higher and a reaction time of 30℃.
The difference is that the feedstock oil is hydrogenated in the first reforming step, and then heat-treated in the second reforming step to generate mesophase. The aforementioned Tokukai Sho
This method is similar to the method of No. 57-16897, etc., and a partially hydride coexisting therewith has a hydrogen-donating effect. In view of the above-mentioned circumstances, the inventors of the present invention have aimed to suppress the formation of high-molecular weight substances that are overly reacted during the thermal reforming reaction, and to speed up the thermal reforming reaction as a whole. As a result of various studies on reforming methods that simultaneously produce raw material pitch for producing carbon fiber with economically desirable properties in high yield through only a thermal reforming process, we found that a When a heavy oil mainly composed of aromatic compounds with 4 or more rings and their partially hydrogenated products is added to the distillation residual oil with a boiling point of 400℃ or higher and a thermal reforming reaction is carried out, the excellent hydrogen Due to the donating property, the rapid pitching property of the added oil itself, and the initial carbonization modification property that modifies the heavy components of the coexisting decant oil and develops mesophases with good properties when the added oil becomes pitchy, The present inventors have discovered that a raw material pitch suitable for producing high-quality carbon fiber can be produced only by a thermal modification process, a subsequent insoluble substance separation process, and a vacuum distillation process, and have completed the present invention. The present invention will be explained in detail below. The present invention uses (A) 50 to 90 parts by weight of a distillation residual oil with a boiling point of 400°C or higher obtained by removing light fractions by distillation from decant oil produced as a by-product from a fluid catalytic cracker using petroleum as a raw material;
(B) Aromatic heavy oil containing 60 wt% or more of aromatic compounds with 4 or more rings and their partially hydrogenated products 50
A mixture consisting of ~10 parts by weight is subjected to a thermal reforming reaction in an inert atmosphere at a reaction temperature of 400 to 470°C for a reaction time of 1 to 10 hours, after which insoluble substances are separated and removed from the reaction product and optically A high-strength, high-modulus carbon characterized by obtaining a pitch having an optically anisotropic portion of 70% or more by obtaining an optically isotropic pitch and then removing a light fraction from this by vacuum distillation. The present invention relates to a method for producing raw material pitch for fibers. In the present invention, decant oil is a by-product oil containing a large amount of aromatic hydrocarbons that is generated from a fluid catalytic cracker whose main purpose is to obtain a product rich in gasoline fractions in the oil refining process. . The raw material oil for this equipment is normally vacuum gas oil produced from a vacuum distillation equipment, but in addition to this, the gas oil fraction, atmospheric distillation residual oil, and atmospheric distillation residual oil produced from an atmospheric distillation equipment are used in a hydrodesulfurization equipment. A mixture of oils that have been hydrogenated or oils whose main component is wax produced from solvent dewaxing equipment, which is a lubricating oil refining equipment, is used. Amorphous silica as a catalyst
Reaction temperature in the presence of alumina, silica-magnesia-based catalysts or zeolite-based catalysts
470~540℃, reaction pressure 0.5~5Kg/ ^cm2G , catalyst/
A catalytic cracking reaction is carried out at an oil ratio of 5 to 15, and the residual oil is extracted from the residual oil obtained by removing the main product, gasoline fraction, etc., from the distillation residual oil attached to this fluid catalytic cracker. Remove the catalyst to obtain decant oil. In the present invention, light fractions are removed from this decant oil by distillation to obtain a distillation residual oil having a boiling point of 400°C or higher. As the distillation method at this time, vacuum distillation is preferably used. Further, aromatic compounds having four or more rings and partially hydrogenated products thereof refer to the following. That is, the aromatic compound having 4 or more rings refers to one or more kinds selected from the group such as pyrene, naphthacene, chrysene, benzanthracene, perylene, benzoperene, benzonaphthacene, picene, thiolanthrene, etc., and their alkyl derivatives. It means a mixture. Also 4
The partial hydrogenation product of an aromatic compound having more than one ring means a compound in which hydrogen is added to a part of the aromatic ring of the above-mentioned substance. It is preferable that a partial hydride having a nuclear hydrogenation rate of 50% or less is the main component of the partial hydride. It is necessary that the aromatic heavy oil used in the present invention contains 60 wt % or more of the above-mentioned aromatic compounds having four or more rings and a mixture of partially hydrogenated products thereof. In addition to preparing the aromatic heavy oil from one or more of the above-mentioned components, it can also be produced by the following method. In other words, it is produced by hydrotreating coal tar produced by carbonization of coal, a distillation fraction of coal tar, or a distillation residue, and then removing light components by distillation, or by liquefying coal. Hydrotreating the liquefied product,
It is then manufactured by removing light components by distillation. To explain in more detail, in the former case, coal tar, creosote oil, anthracene oil, etc. are used as raw materials, and a hydrogenation catalyst containing a sulfide of a metal of a group and/or group of the periodic table is used in a high-temperature, high-pressure hydrogen atmosphere. The hydrogenation reaction is carried out at
In particular, using a nickel-molybdenum sulfide or cobalt-molybdenum sulfide catalyst, the reaction temperature is 280~280°C.
360℃, reaction pressure 50-200Kg/ ^cm2G , hydrogen/raw material ratio
Conditions of 300 to 3000 volumes/volume and a liquid hourly space velocity of 0.5 to 2 volumes/volume are preferred. Further, during this hydrogenation, a method is preferably used in which 0.2 to 10% by weight of phenol and/or alkylphenol whose side chain alkyl group has a total number of carbon atoms of 1 to 3 is added. As the alkylphenols mentioned here, cresols, xylenols, methylethylphenols and propylphenols are preferably used. In the latter case, coal liquefied products include carbonization liquefaction, which involves heating coal to high temperatures and recovering the distilled tar components, solvent extraction liquefaction, which extracts coal with a solvent, and extraction of coal with a hydrogen-donating solvent. Extraction chemical decomposition liquefaction method that simultaneously decomposes
Those produced by the extraction hydrogenation and liquefaction method in which solvent extraction is carried out under the supply of high-pressure hydrogen gas, and the direct hydrogenation and liquefaction method in which hydrocracking of coal is carried out using a catalyst under the supply of high-pressure hydrogen gas are used. The conditions for hydrotreating this coal liquefied material are the same as in the former case.
Light oil components are removed from these oils by distillation to obtain distillation residual oil with a boiling point of 400°C or higher. At this time, vacuum distillation and steam distillation are used, and vacuum distillation is preferably used. These distillation residues
The components are analyzed by means such as NMR and gas claw mass spectrometry, and the mixture containing 60 wt % or more of an aromatic hydrocarbon having 4 or more rings and a partially hydrogenated compound thereof is used as (B) of the present invention. 60wt
If it is less than %, the initial carbonization modification property in the subsequent thermal reforming reaction will not be expressed satisfactorily. In addition, the aromatic compounds having 4 or more rings and the mixture of these partially hydrogenated compounds, which are the components of (B), are the aromatic compounds having 4 or more rings.
50 wt%, and preferably 80 to 50 wt% of a partially hydrogenated aromatic compound having four or more rings. For example, the proportion of partial hydride is 50wt%
In the case of less than
If it exceeds 80wt%, pitching will be slow. In any case, when the aromatic compound and the partially hydrogenated product are within the above-mentioned specific ranges, both the hydrogen donating property and the initial carbon modification property are most preferably exhibited. In the thermal reforming reaction, a mixture of distillation residual oil (A) obtained from the above-mentioned decant oil and aromatic heavy oil (B) is used as a raw material oil. The mixing ratio is 50 to 90 parts by weight of (A) and 50 to 10 parts by weight of (B). The mixing ratio of (B) is 10
If the amount is less than part by weight, it will be used in the subsequent thermal reforming reaction.
Since hydrogen donating properties and initial carbonization modification properties, which are the effects of (B), are hardly exhibited, high-quality carbon fibers cannot be produced from this thermal reforming reaction product. Especially during spinning, there are many yarn breakages and it is not possible to wind the yarn at high speed. Another drawback is that the strength and elastic modulus of the fiber after firing are low. If the mixing ratio of (B) exceeds 50 parts by weight, the amount of aromatic compounds with 4 or more rings and their partially hydrogenated products will be too large relative to the amount of the components of the decant oil, and in this case, the spinning temperature will be too high.
When the temperature drops below 300℃, the fibers fuse after winding.
In addition, since more defects are generated during the infusibility process, the strength and elastic modulus of the fiber after firing are lowered. Thermal reforming reaction is carried out using a continuous heating device or batch heating device under nitrogen gas aeration or in an inert atmosphere such as saturated steam of raw oil or reaction product oil at a reaction temperature of 400 to 470°C for a reaction time of 10. This is carried out by heat treatment while stirring under conditions of less than 1 hour. At this time, in order to shorten the thermal reforming reaction time, the gauge pressure is 0.5 to 5 kg/cm ² , preferably 1 kg/cm 2 .
Reaction temperature 440-460 under low pressure of ~3Kg/ ^cm2
It is preferable to carry out the heat treatment under the conditions of 1 to 2 hours of reaction time and removing the generated light components and gas components without nitrogen aeration.
If the reaction temperature is less than 400°C, the progress of the thermal reforming reaction will be extremely slow, making it uneconomical. Also, the reaction temperature
If the temperature exceeds 470°C, the polycondensation reaction progresses significantly, causing a buildup of caulking on the wall of the reaction vessel, and furthermore, the spinnability of the resulting raw material pitch is poor.
In particular, thread breaks occur frequently. Furthermore, if the reaction time exceeds 10 hours, the hydrogen donating property of the partially hydride is lost, and the spinnability of the resulting raw material pitch is reduced. The properties of the thermal modification reaction product are 1 to 5 wt of quinoline insoluble matter.
%, and the toluene insoluble content is 10 to 30 wt%. In this thermal reforming reaction, the component (A) and the component (B) undergo a co-carbonization reaction to produce a component preferable as a raw material pitch for producing carbon fibers. The details of this co-carbonization reaction are not completely clear, but when the component (A) undergoes thermal decomposition and polycondensation reaction during the thermal reforming reaction, partial hydrogen in the component (B) The compound releases hydrogen and suppresses the excessive progress of the polycondensation reaction, while the aromatic compound having four or more rings, which is another component of (B), causes the polycondensation reaction. Therefore, while suppressing the production of polymeric substances, the thermal reforming reaction proceeds rapidly as a whole, and a pitch-like material with good flatness and excellent graphitization properties is produced. Especially 4
It is noteworthy that partially hydrogenated aromatic compounds with more than one ring change into the corresponding aromatic compounds with four or more rings after releasing hydrogen, so they have both hydrogen donating properties and initial carbon modification properties. This is why the present invention was first achieved by discovering a coexisting substance that has such an effect during a thermal reforming reaction. This effect is particularly large in partial hydrides with a nuclear hydration rate of 50% or less, and in partial hydrides with a nuclear hydration rate of over 50%, the effects on both hydrogen donating properties and initial carbon modification properties are small. Also 3
Partially hydrogenated aromatic compounds below the ring only have hydrogen-donating properties, are hardly pitched themselves, and do not have the above-mentioned initial carbonization modification properties. Furthermore, since these have a low boiling point, when the thermal reforming reaction is carried out at normal pressure, they will escape out of the system and have little effect. Furthermore, when pressurizing, high pressure is required, which reduces the economic efficiency of the device. In the present invention, if (A)(B) contains a fraction with an azeotropic point of less than 400°C, the yield will not only decrease, but also the cocarbonization modification property will decrease. It is necessary that it not be contained. The co-carbonization modification property (B) does not work well on any heavy oil. For example, even when similar thermal reforming reactions were carried out by mixing (B) with coal tar pitch or high-temperature steam cracking pitch of crude oil, good results could not be obtained. This is thought to be because the co-carbonization modification property of (B) is hardly expressed for pitches that are already extremely aromatic, such as coal tar pitch. According to the experimental studies conducted by the present inventors, the co-carbonization modification property of (B) was expressed best for distillation residual oil of decant oil at 400°C or higher. In the present invention, the thermal reforming reaction may be carried out in one stage, and the subsequent steps may include only the step of separating and removing insoluble substances and the step of distillation under reduced pressure. Separation and removal of insoluble substances is carried out using gravity, centrifugal force, etc. at a temperature of 380° C. or lower. The reason why the temperature was set at 380°C or less was to prevent the formation of optically anisotropic substances due to this heating. Alternatively, extraction using aromatic crude oil such as quinoline or anthracene oil is also possible. By separating and removing these insoluble substances, it is possible to remove substances that do not melt during spinning. The pitch-like material produced here has no optically anisotropic portion and is isotropic even when observed under a polarizing microscope. The components constituting mesophase have already been produced in the thermal reforming reaction, but they are thought to be observed isotropically because they are diluted by the light oil that is simultaneously produced by the thermal decomposition reaction in the thermal reforming process. When the light oil content is removed by vacuum distillation, the molecules that make up the mesophase that have already been generated in the thermal reforming reaction are able to be located close to each other, stacked together by van der Waals forces, and polarized light. Optical anisotropy appears under the microscope. It is also one of the features of the present invention that the meso phase is formed by a vacuum distillation process. The properties of pitchchi after vacuum distillation are quinoline insoluble content 5
It is preferable that the toluene insoluble content be 70 to 95 wt%, and the optical anisotropy content as determined by polarizing microscopy be 70% or more. In other words, the quinoline insoluble content is 30wt.
% or when the toluene insoluble content exceeds 95 wt%, the spinning temperature becomes high and the spinning properties are poor, such as frequent yarn breakage. Also, the quinoline insoluble content is 5wt.
If the toluene insoluble content is less than 70wt%, there will be many yarn breakages during spinning, and the fibers will fuse after spinning. Furthermore, if the optically anisotropic portion is less than 70%, there is a drawback that the strength and elastic modulus of the fiber after firing are low. Furthermore, the raw material pitch for producing carbon fiber produced by the method of the present invention has good spinnability, carbonization and graphitization properties. That is, it is possible to spin fibers with a diameter of 5 to 15 μm at a spinning temperature of 300 to 400° C. and a winding speed of 500 m/min, and there is little chance of yarn breakage.
Furthermore, since the spun pitch fibers have high strength, subsequent handling is easy. This pitch fiber is
Infusibility can be achieved by air oxidation at temperatures of 150 to 350°C, and no fusion of the fibers occurs. After carbonization treatment and graphitization treatment, the properties of strength, elastic modulus, and elongation are particularly excellent. As described above, the method described in the present invention represents a method for producing a raw material pitch for producing high-quality carbon fibers, and makes an extremely large contribution in an industrial sense. Next, the present invention will be explained in detail with reference to examples, but the present invention is not limited to the following examples unless the gist of the present invention is exceeded. Example 1 Feedstock oil mainly composed of vacuum gas oil from Middle East crude oil was catalytically cracked in a fluid catalytic cracker using a zeolite catalyst at a reaction temperature of 510°C, a pressure of 2.5 kg/cm ² and a G catalyst/oil ratio of 10. The catalyst was removed from the resulting heavy product oil, and the resulting decant oil was distilled under reduced pressure to remove light components to obtain a distillation residual oil (hereinafter referred to as 1-A) with a boiling point of 400° C. or higher. The properties of 1-A are specific gravity (15/4℃) 1.12, residual coal 12.3wt%, and sulfur content 1.21wt.
It was %. In addition, heavy anthracene oil obtained by vacuum distillation of coal tar was reacted using a nickel sulfide-molybdenum catalyst at a reaction temperature of 340°C and a reaction pressure of 150 kg/cm ^{2 .}
(G), Hydrogenation is carried out in a small continuous flow equipment under the condition of liquid hourly space velocity of 1.0 volume/volume, and the light components are removed from the resulting hydrogenated oil by vacuum distillation, and the 4-ring is heated to a boiling point of 400°C or higher. A distillation residual oil (hereinafter referred to as 1-B) containing 81 wt% of the above aromatic compounds and their partially hydrogenated products was obtained. Its properties are shown in Table 1. A mixture of 60 parts by weight of 1-A and 40 parts by weight of 1-B was heated at a reaction temperature of 460°C under a pressure of 1 kg/cm ² G while stirring in a nitrogen atmosphere using a batch type thermal reformer.
The thermal reforming reaction was carried out under conditions of a reaction time of 1.5 hours.
The properties of the thermally modified product are shown in Table 2. From this, insoluble substances were separated and removed by quinoline extraction, and then light components were removed by vacuum distillation to obtain raw material pitch for carbon fibers. Its properties are shown in Table 3. When this pitch was melt-spun at a spinning temperature of 352°C using a spinning nozzle with a hole diameter of 0.4 mmφ, fibers with a diameter of 10 μ could be spun at a winding speed of 600 m/min without any yarn breakage occurring once in 5 minutes. It was hot. After making this pitch fiber infusible at 300℃ in an air atmosphere,
After carbonization treatment up to a temperature of 1000°C in a nitrogen gas atmosphere, graphitization treatment was performed up to a temperature of 2500°C in an argon atmosphere. The carbon fiber fired at 1000°C had a tensile strength of 20 t/cm ² and the elastic modulus of 1800 t/cm ² , and the graphitized fiber fired at 2500°C had a tensile strength of 28 t/cm ² and an elastic modulus of 3000 t/cm ² . Example 2 A mixture of 80 parts by weight of 1-A and 20 parts by weight of 1-B was thermally reformed using a batch type thermal reformer under conditions of a reaction temperature of 420°C and a reaction time of 7 hours while stirring under a nitrogen atmosphere at normal pressure. The reaction was carried out. The properties of the thermally modified product are shown in Table 2. This was heated to 360°C and allowed to stand to precipitate insoluble substances, and the insoluble substances were separated and removed. Thereafter, light components were removed by distillation under reduced pressure to obtain raw material pitch for carbon fibers. Its properties are shown in Table 3. When this pitch was melt-spun using a spinning nozzle with a hole diameter of 0.5 mmφ at a spinning temperature of 365°C,
At a winding speed of 500 m/min, it was possible to spin fibers with a diameter of 12 μm without any yarn breakage occurring once in 5 minutes. This pitch fiber was made infusible at 300°C in an air atmosphere, carbonized at a temperature of 1000°C in a nitrogen gas atmosphere, and then graphitized at a temperature of 2500°C in an argon atmosphere. Carbon fiber fired at 1000℃ has a tensile strength of 18t/cm ² and an elastic modulus of 1550t/cm ² .
Graphitized fiber fired at 2500℃ has a tensile strength of 26t/
cm ² and elastic modulus of 2650t/cm ² . Example 3 Boiling point 360 obtained by distilling coal tar under reduced pressure
Add 2.5wt of cresol to 97.5wt% of distillation residue above ℃
% added, using a nyl sulfide-molybdenum catalyst at a reaction temperature of 320℃ and a reaction pressure of 150Kg/cm ²
(G), Hydrogenation is carried out in a small continuous flow equipment under the condition of liquid hourly space velocity of 1.0 volume/volume, light components are removed from the resulting hydrogenated oil by vacuum distillation, and the 4-ring is heated to a boiling point of 400°C or higher. A distillation residual oil (hereinafter referred to as 3-B) containing 77.5 wt% of the above aromatic compounds and their partially hydrogenated compounds was obtained. The properties are shown in Table 1. A mixture of 1-70 parts by weight and 30 parts by weight of 3-B was stirred in a batch type thermal reformer under a nitrogen atmosphere at a pressure of 0.5 Kg/cm ² G and a reaction temperature.
Thermal reforming reaction was carried out under the conditions of 440°C and reaction time of 3 hours. The properties of the thermally modified product are shown in Table 2. From this, insoluble substances were separated and removed by quinoline extraction, and then light components were removed by vacuum distillation to obtain raw material pitch for carbon fiber. Its properties are shown in Table 3. When this pitch was melt-spun using a spinning nozzle with a hole diameter of 0.5 mmφ at a spinning temperature of 338°C, the winding speed was 800°C.
It was possible to spin fibers with a diameter of 9 μm at a speed of m/min without any yarn breakage occurring once in 5 minutes. This pitch fiber was made infusible at 300°C in an air atmosphere, carbonized at a temperature of 100°C in a nitrogen gas atmosphere, and then graphitized at a temperature of 2500°C in an argon atmosphere. Carbon fiber fired at 1000℃ has tensile strength
21t/cm ² and elastic modulus of 1650t/cm ² , and graphitized fiber fired at 2500°C has a tensile strength of 31t/cm ² and elastic modulus of
It was 3900t/ ^cm2 . Example 4 Pulverized Australian sub-bituminous coal of 100 mesh or less 1
Mix 3 parts by weight of tetralin with 3 parts by weight to form a slurry, fill it into an autoclave, and create an initial hydrogen pressure of 40Kg/cm ²
The liquefaction reaction was carried out at a reaction temperature of 415° C. and a reaction time of 1 hour while stirring. Liquefied coal with a boiling point of 350°C or higher obtained by separating unreacted substances and solid content such as ash from the reaction product by filtration, and then removing the solvent and light content by distillation.
A mixture of 97.5 wt% and 2.5 wt% of phenol was reacted using a nickel sulfide-molybdenum catalyst at a reaction temperature of 350°C, a reaction pressure of 150 Kg/cm ² (G), and a liquid hourly space velocity.
Hydrogenation is carried out using a small continuous flow equipment under conditions of 1.0 volume/volume, and light components are removed from the resulting hydrogenated oil by vacuum distillation to produce aromatic compounds with 4 or more rings and their boiling points of 400°C or higher. A distillation residual oil (hereinafter referred to as 4-B) containing 73.2 wt% of partially hydrogenated products was obtained. The properties are shown in Table 1. 1-
A mixture of 75 parts by weight of A and 25 parts by weight of 4-B was subjected to a thermal reforming reaction using a batch type thermal reformer under conditions of a reaction temperature of 430° C. and a reaction time of 6 hours while stirring under a nitrogen atmosphere at normal pressure. This is heated to 360°C and allowed to settle, allowing the insoluble substances to settle. The insoluble substances are separated and removed using a decanting method, and the light components are removed using vacuum distillation to produce a raw material pitch for carbon fiber production. I got it. Its properties are shown in Table 3. When melt spinning was performed using this spinning nozzle with a pitch hole diameter of 0.5 mmφ at a spinning temperature of 372°C, 5
It was possible to spin fibers with a diameter of 13 μm without a single yarn breakage per minute. This pitch fiber was made infusible at 300°C in an air atmosphere, carbonized at a temperature of 1000°C in a nitrogen atmosphere, and then graphitized at a temperature of 2500°C in an argon atmosphere. Carbon fiber fired at 1000℃ has a tensile strength of 18t/cm ² and an elastic modulus of
The graphitized fibers fired at 2500°C had ^{a tensile strength of 25 t/cm 2 and} an elastic modulus of 2750 t/cm ² . Comparative Example 1-A was subjected to thermal reforming reaction, separation and removal of insoluble substances, and vacuum distillation under the same conditions as described in Example 1 to obtain pitch. The properties of the thermally modified product and pitch are shown in Tables 2 and 3, respectively.
This pitch was melt-spun under the same conditions as in Example 1, but there were too many yarn breakages and spinning could not be completed. Also, when the winding speed was reduced to 200m/min, the diameter was 23μ.
The fiber was spun. This pitch fiber was subjected to infusible, carbonized and graphitized treatments under the same conditions as in Example 1. Carbon fiber fired at 1000℃ has tensile strength
13t/cm ² and elastic modulus of 1400t/cm ² , and the graphitized fiber fired at 2500°C has a tensile strength of 15t/cm ² and an elastic modulus of
It was 2250t/ ^cm2 . Comparative Examples 2, 3, and 4 1-B, 3-B, and 4-B were individually subjected to thermal reforming reaction, separation and removal of insoluble substances, and vacuum distillation under the same conditions as described in Example 1. I got it. The properties of the thermally modified product and pitch are shown in Tables 2 and 3, respectively. This pitch was subjected to melt spinning under the same conditions as in Example 1, but in all cases there were too many yarn breakages and spinning could not be completed.

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Claims (1)

[Scope of Claims] 1 (A) Distillation residual oil 50-90 with a boiling point of 400°C or higher obtained by removing light fractions by distillation from decant oil produced as a by-product from a fluid catalytic cracker using petroleum as a feedstock. and (B) 50 to 10 parts by weight of an aromatic heavy oil containing 60 wt% or more of a mixture of aromatic compounds with 4 or more rings and partially hydrogenated products under an inert atmosphere. A thermal reforming reaction is carried out at a reaction temperature of 400 to 470°C for a reaction time of 1 to 10 hours, and then insoluble substances are separated and removed from the reaction product to obtain an optically isotropic pitch, which is then distilled under reduced pressure. A method for producing a raw material pitch for high-strength, high-modulus carbon fiber, characterized in that a pitch with an optically anisotropic portion of 70% or more is obtained by removing light fractions. 2. The mixture of aromatic compounds with 4 or more rings and their partially hydrogenated compounds, which are the components of (B), consists of 20 to 50 wt% of the aromatic compounds with 4 or more rings and 80 to 50 wt% of their partially hydrides. A method for producing a raw material pitch for high-strength, high-modulus carbon fiber according to claim 1, characterized in that: 3 Partial hydrides of aromatic compounds with 4 or more rings, which are components of (B), have a nuclear hydrogenation rate of 50% or less
A method for producing a raw material pitch for high-strength, high-modulus carbon fibers according to claim 1, characterized in that the pitch is comprised of 70 wt% or more. 4. Thermal reforming reaction is carried out under the conditions of pressurization of 0.5 to 5 kg/cm ² gauge pressure, reaction temperature of 440 to 470°C, and reaction time of 1 to 2 hours, while extracting the produced light fraction and gas components. A method for producing a raw material pitch for high-strength, high-modulus carbon fiber according to claim 1. 5 The property of the thermal modification reaction product is quinoline insoluble content 1
~5wt% and toluene insoluble content of 10~30wt%,
The properties of the optically isotropic pitch after separating and removing insoluble substances are 1 wt% or less of quinoline insolubles, and the properties of the pitch after vacuum distillation are 5 to 5% of quinoline insolubles.
30 wt% and a toluene insoluble content of 70 to 95 wt%, the method for producing a raw material pitch for high strength, high elastic modulus carbon fiber according to claim 1.