JPS6249366B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention is directed to the use of butane or a mixture containing butane as a main component, pentane or a mixture containing pentane as a main component, and/or hexane or a mixture containing hexane as a main component as a solvent, and vacuum residual oil as a solvent. The asphaltene obtained by extraction and deasphalt mainly composed of resin are used as starting materials and thermally modified to produce thermally modified asphalt with a benzene insoluble content (BI) of 50% or more, preferably about 70%. The present invention relates to a method for producing carbon fiber, using this thermally modified asphalt as a new raw material for producing carbon fiber or graphite fiber (hereinafter simply referred to as carbon fiber). [Prior Art] Traditionally, carbon fibers have been manufactured by using Celerose fibers, acrylonitrile fibers, etc. as raw materials, but these methods have the disadvantage that the raw materials are expensive and are not suitable for mass production. It was hot. In addition, as a method to improve this, there is a method in which a pitch-like material obtained by thermally decomposing and heat-treating a hydrocarbon compound such as crude oil or coal pitch, and then hydrogenating it using a catalyst is used as a raw material. [Problems to be Solved by the Invention] However, this method has disadvantages in that the processing steps are complicated and expensive raw materials such as catalysts and hydrogen are used. In order to solve the above-mentioned problems, the present invention was made by paying attention to the fact that petroleum-based heavy oils such as vacuum residual oil and solvent-deasphalted asphalt are becoming oversupplied. After oxidizing petroleum-based heavy oil using an oxidizing agent such as hydrogen peroxide, oxygen, air, or ozone as necessary, it is oxidized at 350 to 420°C under a pressure of normal pressure to 10 Kg/cm ² G, 0.5 ~
Thermal modification is carried out for 8 hours to obtain thermally modified asphalt containing 50% or more of benzene insoluble matter, and this thermally modified asphalt is formed by melt spinning and then subjected to infusibility treatment and firing treatment to achieve low cost. The purpose of this invention is to provide a method for manufacturing carbon fiber suitable for mass production. [Means and effects for solving the problem] The method for producing carbon fiber according to the first invention of the present application includes butane or a mixture containing butane as a main component, pentane or a mixture containing pentane as a main component, and/or hexane or Petroleum-based heavy oils such as asphaltene obtained by solvent extraction of vacuum residual oil using a mixture mainly composed of hexane and solvent-deasphalted asphalt mainly composed of resin are extracted at normal pressure to 10 kg/cm ² G. Under pressure, 350~420℃, 0.5~8
It is characterized by performing thermal modification for a period of time to obtain thermally modified asphalt containing 50% or more of benzene insoluble matter, molding this thermally modified asphalt by melt spinning, and then subjecting it to infusibility treatment and firing treatment. In addition, the method for producing carbon fiber according to the second invention of the present application uses butane or a mixture containing butane as a main component, pentane or a mixture containing pentane as a main component, and/or hexane or a mixture containing hexane as a main component as a solvent under reduced pressure. After oxidizing petroleum-based heavy oils such as asphaltene obtained by solvent extraction of residual oil and solvent-deasphalted asphalt whose main component is resin using an oxidizing agent such as hydrogen peroxide, oxygen, air, or ozone, Thermal modification is performed at 350 to 420°C for 0.5 to 8 hours under a pressure of normal pressure to 10 Kg/cm ² G,
The method is characterized by obtaining heat-modified asphalt containing 50% or more of benzene-insoluble matter, molding this heat-modified asphalt by melt spinning, and then subjecting it to infusibility treatment and firing treatment. Hereinafter, the configuration of the present invention will be explained in detail.
Vacuum residue is a concentrate of heavy components in crude oil, but this substance contains components that are soluble in light paraffinic solvents and components that are insoluble in light paraffinic solvents, and the soluble components are further finely separated into solvents. When this is done, it is separated into saturated components, aromatic components, resin components, etc. The proportions of these components vary depending on the type of raw oil, and as shown in Table 1, in the vacuum residue of heavy crude oil, the amount of asphaltene, which is an insoluble content, accounts for around 20%. Table 1 shows the results of testing the properties of the vacuum residue of Gatsuchi Saran crude oil and the vacuum residue of Khafji crude oil.

[Table] The characteristic feature of the deasphalt, which is the starting material in the present invention, is that the asphalt has been pretreated by solvent extraction to remove as much of the petrolene (or malten), which is a soluble component and does not contribute to the production of carbon fibers, as much as possible. As a result of various studies, it was found that solvent extraction of vacuum residual oil using butane, pentane, hexane, or a solvent containing these as the main components would maximize the yield of deasphalted oil and be suitable for the production of carbon fiber. It was found that this is the most suitable method for obtaining deasphalted asphalt. Research has also shown that it is possible to separate the resin component, which is one of the soluble components, from deasphalted asphalt in a solvent extraction operation, but since the resin component contains functional groups and is highly chemically active, it is possible to separate the resin component from deasphalted asphalt. It was found that it is useful as a raw material for carbon fibers because it becomes a solvent-insoluble component (asphaltene) under such conditions and contributes to improving the properties of carbon fibers. Therefore, it has become possible to use deasphalted asphalt with residual resin components as a raw material, and it has been found that a wide range of extraction conditions can be adopted as operating conditions in the solvent deasphalt process (see Table 2). Table 2 shows the results of testing the properties of pentane-deasphalted asphalt from the vacuum residue of Gatchisaran crude oil and pentane-deasphalt asphalt from the vacuum residue of Khafji crude oil.

【table】

[Table] On the other hand, the results obtained by testing the relationship between solid content yield and volatile content in the thermal reforming process for pentane deasphalt asphalt, Kafji vacuum residual oil, coal tar pitch, and naphsa tar pitch are shown below. A curve as shown in FIG. 1 is obtained. From Fig. 1, it was found that the thermal reforming process of asphalt is similar to that of coal tar pitch, which is a good coke raw material. Furthermore, Table 3 shows a comparison of the activation energy in the reaction for producing quinoline insoluble matter, which is one measure of the polycondensation reaction by thermal modification, for various raw materials.

〔Effect of the invention〕

As explained above, according to the method of the present invention,
By using deasphalted asphalt using butane, pentane, hexane, or a mixture containing these as the main components as a raw material, the polycondensation reaction can easily proceed under mild reaction conditions to produce high-quality carbon fiber raw materials. Is possible. In terms of the manufacturing process, compared to the conventional technology that uses pitch as a raw material, it has a much wider range of operation, is more stable, more economical, and is a more energy-saving process. It has better properties than those of the conventional method and is extremely useful. [Examples] Examples of the present invention will be described below. Example 1 Pentane deasphalt (Gatsuchi Saran)
Pour 100g into a 0.5 autoclave and make 0.5Nl/
The mixture was heated to 400°C at a rate of 5°C/min while flowing N ₂ gas at a flow rate of 20°C, and heat-treated for 2 hours to obtain a highly aromatic pitch-like substance (softening point: 250°C). This product was formed into a fiber by an extrusion melt-spinning method, and then heated to 250°C at a rate of 1 to 2°C/min in air for infusibility, and kept at that temperature for 30 minutes. Carbonization was carried out by increasing the temperature to 1100°C at a rate of 10°C/min in N ₂ gas. The diameter of the obtained carbon fiber is 7~
12μ, strength was 11-13t/cm ² , elongation was 1-1.5%, and carbon yield was about 93%. Example 2 Deasphalted asphalt obtained from Kafji crude oil vacuum residue using pentane as a solvent was pulverized to 60 mesh or less, and 120 g was weighed into a round bottom flask equipped with a stirrer and a reflux condenser, and hydrogen peroxide was added. (30% aqueous solution) and 200 g of acetic acid were mixed and stirred at room temperature to form a slurry. Thereafter, the temperature of the contents of the flask was raised to 100° C. with a mantle heater while stirring. During the reaction, the contents of the flask came to a boiling state, and the generated vapor was concentrated in a reflux condenser and returned to the flask. The reaction was completed in 1 hour. After the reaction was completed, the mixture was washed with water and dried at 110°C for 3 hours to obtain a highly aromatic pitch-like oxide. 100 g of the oxidation sample obtained in this way was collected, and a stainless steel 0.5
It was placed in an autoclave and heat treated at 390°C for 2 hours while purging with N ₂ gas at a flow rate of 0.5/min. This product was formed into a fiber by an extrusion melt spinning method, and then heated to 1000°C at a rate of 10°C/min for carbonization. The diameter of the obtained carbon fiber is 7 to 10 μ, the strength is 9 to 12 t/cm ² , and the elongation is 0.7.
It was ~1.1%. Example 3 Deasphalted asphalt obtained from Kafji crude oil vacuum residue using pentane as a solvent was used as a raw material, and 1.2 kg/hour was supplied to a continuous high temperature (350-420°C) kneader type heat treatment equipment with a processing capacity of 1.5 kg/hr. Heat treatment was carried out continuously at a heat treatment temperature of 400°C, an average residence time of 2 hours, and a kneader rotation speed of 45 rpm to obtain a highly aromatic pitch-like substance with a benzene insoluble content of 45% and a softening point of 268°C. After forming this into a fiber using an extrusion type melt-spinning method, the temperature is raised to 260°C at a rate of 0.5 to 1°C/min in air to make it infusible by performing an oxidation treatment, and then by a conventional method. It was heated to 1100°C and carbonized. The diameter of the obtained carbon fibers is 10-15
μ, strength was 10 to 11 t/cm ² , and elongation was 0.7 to 1.2%.

[Brief explanation of the drawing]

Figure 1 shows deasphalt, vacuum residual oil, coal tar pitch, and naphtha tar pitch.
A curve diagram showing the relationship between the solid content yield and the amount of volatile matter in the thermal reforming process, Figure 2 is a curve diagram showing the relationship between the amount of quinoline insoluble matter and the Button index when deasphalted asphalt is modified under normal pressure, Figure 3 is a curve diagram showing the relationship between the amount of quinoline insoluble matter and the Button index when deasphalted asphalt is modified under pressure.
The figure is a curve diagram showing the relationship between the benzene insoluble content and the Loga index when deasphalted asphalt and vacuum residual oil are thermally reformed, and Figure 5 shows the degree of sulfonation when deasphalt is subjected to oxidation treatment. , a graph showing the relationship with the aromaticity index, which is an index indicating the degree of dehydrogenation cyclization reaction. Figure 6 shows the solid content yield during thermal reforming for oxidized deasphalt asphalt and unoxidized deasphalt asphalt. Figure 7 shows the relationship between the solid content yield and the benzene insoluble content in the solid content for oxidized deasphalt asphalt and unoxidized deasphalt asphalt. FIG. 8 is a graph showing the relationship between solid content yield and β resin in the solid content for oxidized deasphalt asphalt and unoxidized deasphalt asphalt.

Claims (1)

[Claims] 1. Obtained by solvent extraction of residual oil under reduced pressure using butane or a mixture containing butane as a main component, pentane or a mixture containing pentane as a main component, and/or hexane or a mixture containing hexane as a main component as a solvent. Petroleum-based heavy oils such as asphaltene and solvent-deasphalted asphalt whose main component is resin are heated at 350 to 420°C under a pressure of normal pressure to 10 kg/cm ² G.
Thermal modification is performed for 0.5 to 8 hours to remove benzene insoluble matter by 50%.
1. A method for producing carbon fibers, which comprises obtaining heat-modified asphalt containing % or more, molding the heat-modified asphalt by melt spinning, and then subjecting it to infusibility treatment and firing treatment. 2. Asphaltenes and resin components obtained by solvent extraction of vacuum residual oil using butane or a mixture containing butane as a main component, pentane or a mixture containing pentane as a main component, and/or hexane or a mixture containing hexane as a main component as a solvent. After oxidizing petroleum-based heavy oil such as solvent-deasphalted asphalt, which is the main component, using an oxidizing agent such as hydrogen peroxide, oxygen, air, or ozone, it is oxidized under a pressure of normal pressure to 10 kg/cm ² G to 350 ml. Heat modification was performed at ~420℃ for 0.5 to 8 hours.
A method for producing carbon fibers, which comprises obtaining heat-modified asphalt containing 50% or more of benzene-insoluble matter, molding the heat-modified asphalt by melt spinning, and then subjecting it to infusibility treatment and firing treatment.