Method for producing mesophase pitch

Abstract

To provide a method for producing mesophase pitch using a biomass-derived raw material which has not been used as a pitch raw material so far.SOLUTION: Using a bio-crude, a hydrogenated bio-crude, or a solvent-soluble component of the bio-crude as a first raw material, and at least one selected from a petroleum-based residue having a hydrogen donating property and a reformed product of the petroleum-based residue as a second raw material, A mixed-raw-material preparation step S10 of preparing a mixed raw material containing at least a first raw material and a second raw material, a eutectic pitching step S20 of performing a eutectic pitching reaction on the mixed raw material, and a pitch preparation step S30, wherein the mixed raw material is a first mixed raw material containing a bio-crude, the second raw material, and a melting accelerating agent, a second mixed raw material containing a hydrogenated bio-crude and the second raw material, or a third mixed raw material containing a bio-crude solvent-soluble component and the second raw material.SELECTED DRAWING: Figure 16

Description

[Technical Field]

[0001] The present invention relates to a method for producing mesophase pitch. [Background technology]

[0002] Coal-based pitch and petroleum-based pitch have been used as raw materials for mesophase pitch for high-performance carbon materials. For example, pitch obtained by modifying coal tar, a by-product of coke production for steelmaking, is known. Also known is pitch obtained by modifying heavy components such as hydrogenation residues and solvent deasphalting residues from petroleum refining.

[0003] Various studies have been conducted on the production method of mesophase pitch. For example, Patent Document 1 describes a process for preparing mesophase lignin and its carbon fiber. The process includes a step of heating and maintaining a modified lignin at a predetermined temperature in an inert gas atmosphere to polycondense the modified lignin and form a mesophase aromatic structure, thereby obtaining mesophase lignin with good fluidity and optical anisotropy. Patent Document 2 describes a method for preparing mesophase pitch-based carbon fiber obtained by liquefying and modifying sawdust. The preparation method includes the steps of obtaining a sawdust liquefaction liquid, mixing the sawdust liquefaction liquid with oil-based mesophase asphalt and activating the mixture under predetermined conditions, preparing modified oil-based mesophase pitch fiber by heating the activated mesophase pitch under predetermined conditions, and performing an oxidation treatment under predetermined conditions. Patent Document 3 describes a process for preparing spinnable mesophase pitch and pitch-based carbon fibers. The process has an aromatic carbon ratio C A The process includes the steps of placing a raw material, which is a uniform mixture of 40% aromatic oil and biomass, in a corrosion-resistant reactor together with a Lewis acid catalyst, and carrying out a catalytic polycondensation reaction under predetermined conditions to obtain mesophase asphalt; and sequentially subjecting the mesophase asphalt to melt spinning, pre-oxidation, carbonization, and graphitization to prepare asphalt-based carbon fiber. Patent Document 4 describes a method for preparing mesophase asphalt. The method includes the steps of obtaining filtered biomass asphalt, preparing a mixed solvent, preparing a mixed asphalt, mixing the mixed asphalt and the mixed solvent at a certain weight ratio and placing the mixture in a pressure separation vessel, heating the mixture in the pressure separation vessel under specified conditions and then maintaining it at a constant temperature for a certain period of time, obtaining a refined mixed asphalt, and placing the refined mixed asphalt in a pressure polymerization reactor and performing a co-carbonization thermal polycondensation reaction under specified conditions to obtain mesophase asphalt. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Chinese Patent Application Publication No. 103451777 [Patent Document 2] Chinese Patent Application Publication No. 106087116 [Patent Document 3] Chinese Patent Application Publication No. 112877087 [Patent Document 4] Chinese Patent Application Publication No. 114164014 Summary of the Invention [Problem to be solved by the invention]

[0005] The main suppliers of mesophase pitch are the petroleum refining, steelmaking, and coke manufacturing industries. However, due to a decline in fuel oil demand, a decline in the amount of high-quality coking coal resources and a rise in prices, and the global shift to cokeless operations such as electric furnaces, which have a lower greenhouse gas (GHG) load, the supply of pitch, a by-product, is dwindling and it is predicted that it will not be able to meet future demand. Meanwhile, in recent years, as disclosed in Patent Documents 1 to 4, the production of mesophase pitch using raw materials derived from biomass has been investigated.

[0006] An object of the present invention is to provide a method for producing mesophase pitch by using a biomass-derived raw material that has not been able to be used as a pitch raw material until now. [Means for solving the problem]

[0007] [1] A first feedstock is a biocrude, a biocrude hydrogenated product obtained by hydrogenating the biocrude, or a biocrude solvent-soluble fraction obtained by solvent-treating the biocrude, and a second feedstock is at least one selected from the group consisting of a petroleum residue having hydrogen donating properties and a modified product of the petroleum residue; a mixed raw material preparation step of preparing a mixed raw material containing at least the first raw material and the second raw material; a co-pitching step of heating the mixed raw material under pressure to carry out a co-pitching reaction on the mixed raw material; and a pitch preparation step of preparing mesophase pitch by subjecting the reaction product obtained in the co-pitching step to reduced pressure; The mixed raw material is a first mixed raw material containing the biocrude, the second raw material, and a melting-promoting solvent that promotes the melting of the biocrude and the second raw material; a second mixed feed comprising the biocrude hydride and the second feed; or A third mixed raw material containing the biocrude solvent-soluble component and the second raw material. A method for producing mesophase pitch. [2] The co-pitching step is a step of subjecting the mixed raw material to the co-pitching reaction under conditions of 0.2 MPa or more and 1.0 MPa or less, 260 ° C or more and 450 ° C or less, and 30 minutes or more and 6 hours or less. The method for producing mesophase pitch according to [1] above. [3] The mixed raw material preparation step is a step of mixing the biocrude, the second raw material, and the melt-promoting solvent. The method for producing mesophase pitch according to [1] or [2] above. [4] In the mixed raw material preparation step, the mixing ratio of the biocrude to the second raw material in the first mixed raw material (the biocrude / the second raw material) is 100 / 200 or more and 100 / 100 or less by mass; The content of the melt-promoting solvent in the first mixed raw material is 650 parts by mass or more and 750 parts by mass or less with respect to 100 parts by mass of the biocrude. The method for producing mesophase pitch according to [3] above. [5] The mixed raw material preparation step includes an intermediate mixed raw material preparation step of mixing the biocrude, the second raw material, the melt-promoting solvent, and a catalyst to prepare an intermediate mixed raw material; a hydrogenation reaction step of subjecting the intermediate mixed feedstock to a hydrogenation reaction to hydrogenate the biocrude to obtain the biocrude hydrogenated product; The method for producing mesophase pitch according to [1] or [2] above. [6] The mixed raw material preparation step includes a removal step of removing the melt-promoting solvent and the catalyst from the intermediate mixed raw material after the hydrogenation reaction step. The method for producing mesophase pitch according to [5] above. [7] In the intermediate mixed raw material preparation step, the mixing ratio of the biocrude to the second raw material in the intermediate mixed raw material (the biocrude / the second raw material) is 100 / 250 or more and 100 / 33 or less by mass; The method for producing mesophase pitch according to [5] or [6] above. [8] The method further includes a solvent treatment step of treating the biocrude with a solvent to obtain a biocrude solvent-soluble fraction before the mixed raw material preparation step, The mixed raw material preparation step is a step of obtaining the third mixed raw material by mixing the biocrude solvent-soluble component and the second raw material. The method for producing mesophase pitch according to [1] or [2] above. [9] In the mixed raw material preparation step, the mixing ratio of the biocrude solvent-soluble matter to the second raw material in the third mixed raw material (the biocrude solvent-soluble matter / the second raw material) is 100 / 250 or more and 100 / 33 or less by mass; The method for producing mesophase pitch according to [8] above.

[10] The biocrude used to obtain the first mixed raw material, the biocrude used to obtain the biocrude hydrogenated product, or the biocrude used to obtain the biocrude solvent-soluble fraction is a dehydrated biocrude product. The method for producing mesophase pitch according to any one of [1] to [9] above.

[11] The co-pitching step is carried out while stirring the mixed raw material. The method for producing mesophase pitch according to any one of [1] to

[10] above.

[12] The method further comprises a carbonization step of carbonizing the mesophase pitch prepared in the pitch preparation step. The method for producing mesophase pitch according to any one of [1] to

[11] above.

[13] The carbonization step is carried out under the conditions of a carbonization temperature of 450°C or higher and 650°C or lower, and a holding time at the carbonization temperature of 30 minutes or higher and 4 hours or lower. The method for producing mesophase pitch according to

[12] above.

[14] The petroleum residue is at least one selected from the group consisting of cracked residue produced when heavy crude oil is cracked using a fluid catalytic cracking unit, vacuum-heated residue obtained by further reducing the pressure of the atmospheric distillation residue of crude oil and distilling it, residue obtained after extracting a heavy fraction from the vacuum-heated residue with propane, and ethylene bottom oil. The method for producing mesophase pitch according to any one of [1] to

[13] above.

[15] When the mesophase pitch prepared in the pitch preparation step is analyzed by FT-IR, the content of oxygen atoms contained in the mesophase pitch is 2.0 mass% or less, and the FT-IR peak at 1270 cm -1 The peak of the ether bond (COC) and the peak of the ether bond (COC) at 1645 cm -1the intensity ratio of the peak of the ether bond to the peak of the aromatic carbon skeleton (the peak of the ether bond / the peak of the aromatic carbon skeleton) is 0.45 or less; The method for producing mesophase pitch according to any one of [1] to

[14] above. [Effects of the Invention]

[0008] According to one aspect of the present invention, there is provided a method for producing mesophase pitch using a biomass-derived raw material that has not previously been usable as a pitch raw material. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a polarizing microscope photograph of carbides of the first raw material (DR). [Figure 2] 1 is a polarizing microscope photograph of carbides of the first raw material (TRs). [Figure 3] 1 is a polarizing microscope photograph of carbide of the first raw material (CLO). [Figure 4] 1 is a polarizing microscope photograph of pitch carbide of Reference Example 1. [Figure 5] 1 is a polarizing microscope photograph of pitch carbide of Reference Example 2. [Figure 6] 1 is a polarizing microscope photograph of pitch carbide of Reference Example 3. [Figure 7] 1 is a polarizing microscope photograph of pitch carbide of Example 1A. [Figure 8] 1 is a polarizing microscope photograph of pitch carbide of Example 1B. [Figure 9] 1 is a polarizing microscope photograph of pitch carbide of Example 1C. [Figure 10] 1 is a polarizing microscope photograph of pitch carbide of Example 3C. [Figure 11] 1 is a polarizing microscope photograph of pitch carbide of Example 5C. [Figure 12] 1 is a polarizing microscope photograph of pitch carbide of Example 6C. [Figure 13] 1 is a polarizing microscope photograph of a graphitized C / C composite. [Figure 14] 1 is a polarizing microscope photograph of a graphite electrode sample. [Figure 15] 1 is a polarizing microscope photograph of pitch carbide of Example 2C. [Figure 16] FIG. 2 is a block diagram showing an example of a manufacturing method according to the present embodiment. [Figure 17] FIG. 2 is a block diagram showing an example of a manufacturing method according to the present embodiment. [Figure 18] FIG. 2 is a block diagram showing an example of a manufacturing method according to the present embodiment. [Figure 19] FIG. 1 illustrates an example of a Cat-HTR™ process. [Figure 20] 1 shows FT-IR charts of the prepared pitches produced in Reference Example 1, Reference Example 3, Example 1A, and Example 1B, as well as DR and CLO. [Figure 21] FIG. 1 is a diagram showing the characterization of the optical structure based on the ether bond and oxygen content contained in pitch and the like. DETAILED DESCRIPTION OF THE INVENTION

[0010] In this specification, a numerical range expressed using "to" means a range that includes the number written before "to" as the lower limit and the number written after "to" as the upper limit. In this specification, mass percent concentration (unit: mass % (mass%)) and weight percent concentration (unit: weight % (wt%)) are the same value.

[0011] [First embodiment] The method for producing mesophase pitch according to this embodiment (hereinafter also referred to as the production method according to this embodiment) is a method for producing mesophase pitch from a raw material derived from biomass. The production method according to this embodiment uses biocrude, a biocrude hydrogenate obtained by hydrogenating biocrude, or a biocrude solvent-soluble fraction obtained by solvent-treating biocrude as a first feedstock, and at least one selected from the group consisting of petroleum residues having hydrogen-donating properties and modified products of the petroleum residues as a second feedstock. The method includes a mixed feedstock preparation step in which a mixed feedstock containing at least the first feedstock and the second feedstock is prepared, a co-pitching step in which the mixed feedstock is heated under pressure to cause a co-pitching reaction on the mixed feedstock, and a pitch preparation step in which the reaction product obtained in the co-pitching step is subjected to reduced pressure treatment to prepare mesophase pitch. The mixed feedstock used in the co-pitching process is the following first mixed feedstock, second mixed feedstock, or third mixed feedstock. First mixed raw material: includes a biocrude, a second raw material, and a melt-promoting solvent that promotes the melting of the biocrude and the second raw material. Second mixed feed: includes biocrude hydride and a second feed. Third mixed raw material: Contains the biocrude solvent solubles and the second raw material.

[0012] The production method of this embodiment produces mesophase pitch by including, in this order, a mixed raw material preparation step of preparing a mixed raw material, a co-pitching step of performing a co-pitching reaction on the mixed raw material, and a pitch preparation step of preparing mesophase pitch.

[0013] In this specification, "mesophase pitch" refers to pitch that can form an optically anisotropic structure when a carbide obtained by carbonizing pitch (hereinafter also referred to as pitch carbide or simply carbide) is observed under a polarizing microscope. A method for observing pitch carbide under a polarizing microscope is described in the Examples section. Note that "isotropic pitch" refers to pitch that can usually only reveal an optically isotropic structure when pitch carbide is observed under a polarizing microscope.

[0014] As used herein, the term "solvent for promoting fusion" refers to an organic solvent added to improve the mutual affinity, particularly the fusion property, between the biocrude and the second raw material by acting as a solvator. Note that the solvent for promoting fusion itself does not become a carbonized product. In this specification, the solvent used in the solvent treatment (hereinafter sometimes referred to as the treatment solvent) means an organic solvent used to dissolve the biocrude, extract the soluble matter, and fractionate the insoluble matter.

[0015] Mesophase pitch, which is used as a raw material for needle coke, is usually produced by modifying coal tar recovered as a by-product from coke ovens in steel manufacturing or petroleum residues from the petroleum refining process. Of these, coal tar is recovered from coke ovens at a yield of approximately 7 to 8 wt%. The coal used is limited to bituminous coal, mainly heavy coking coal. On the other hand, there have been attempts to produce bio-coke by carbonizing biomass from the perspective of decarbonization, but the cold and hot strength of bio-coke is insufficient compared to coke made from hard coking coal, and biomass cannot be used as a coke raw material, so there is no tar from biomass on the market. Therefore, at present, as part of research and development, the use of biomass tar and biomass reformed oil obtained from biomass pyrolysis, liquefaction, gasification, and hot water extraction is being considered, but the main theme is the production of biofuels, which directly contributes to GHG reduction. Furthermore, compared to bituminous coal tar and petroleum residues, biomass tar and reformed oil are rich in aliphatic compounds, have a low proportion of aromatic carbon, a low degree of condensation of aromatic rings, and have a high oxygen content. For this reason, it is said that converting Biomastal into pitch, and especially its application to anisotropic carbon materials, is extremely difficult. In general, these biomass oils contain a high proportion of ether bonds, particularly among the oxygen-containing groups derived from lignin, which facilitates the formation of polymers with three-dimensional crosslinked structures upon heating. This narrow melting range means that even at relatively low temperatures of around 300°C, the QI component (quinoline insoluble matter) increases and solidification begins. Therefore, biomass oils do not undergo the mechanisms of spherulite formation, coalescence, and growth seen in petroleum-based pitch, and have not been able to become mesophase pitch. In other words, biomass oils have a high oxygen content and tend to solidify quickly, making them unsuitable as pitch feedstocks. Carbonizing biomass oils alone always results in isotropic carbon, which has been called non-graphitizable carbon. For the above reasons, no attempts have been made to produce mesophase pitch using biomass oil and develop it into high-value-added anisotropic carbon materials.

[0016] The present inventors have discovered that mesophase pitch can be produced using biomass-derived biocrude as a starting material. Specifically, they discovered that mesophase pitch can be produced by preparing a mixed material (first mixed material, second mixed material, or third mixed material) containing a first material using biocrude and a second material using a petroleum residue having hydrogen donor properties, and then performing a co-pitching reaction on the mixed material. Biocrude has a higher oxygen content than existing mesophase pitch feedstocks. For example, biocrude contains more than twice as many oxygen atoms as lignite synthetic oil. It was thought that the three-dimensional crosslinking structure resulting from ether bonds, among the bonds involving these oxygen atoms, particularly inhibits the development of mesophase. Therefore, in this embodiment, a "hydrogen-donating petroleum residue" is used as the second feedstock, and hydrogen is transferred from the petroleum residue to biocrude during the co-pitch reaction, thereby reducing the ether bonds. In the co-pitching process according to this embodiment, a co-pitching reaction is carried out using a mixed material (first mixed material, second mixed material, or third mixed material) that combines a first raw material and a second raw material. All of these mixed material mixtures are novel combinations of mixed material mixtures for producing mesophase pitch.

[0017] The mesophase pitch obtained by the production method of this embodiment can be used as a high-performance carbon material (for example, needle coke, a binder for steel, a graphite electrode material, etc.). Furthermore, the production method of this embodiment uses biocrude derived from biomass as a raw material, which allows for effective use of the abundant biomass available around the world. Such use of biomass is extremely useful from the perspective of making noble use of unused resources and resolving future shortages of pitch raw materials.

[0018] First, the first raw material and the second raw material will be described. The mixed raw material prepared in the mixed raw material preparation step may contain at least the first raw material and the second raw material.

[0019] [First ingredient] The first raw material is a biocrude, a biocrude hydrogenate obtained by hydrogenating the biocrude, or a biocrude solvent-soluble fraction obtained by solvent treatment of the biocrude.

[0020] <Biocrude> Biocrude is a bio-crude oil derived from biomass, specifically a bio-crude oil obtained by hydrothermal treatment of a mixture containing biomass and water (e.g., biomass slurry) under pressure. This process of "hydrothermal treatment of a mixture containing biomass and water under pressure" is based on the Cat-HTR technology developed by Licella Holdings, an Australian company. TM This process is also called a subcritical hydrothermal catalytic reaction process. Figure 19 shows the Cat-HTR TM FIG. 1 illustrates an example of a process. Cat-HTR shown in Figure 19 TMIn the process, biomass slurry, a mixture of biomass and water, is first subjected to subcritical hydrothermal treatment at 240 atmospheres and 350°C in the presence of a catalyst, and the pressure is instantly reduced to atmospheric pressure to separate gas (approximately 20% to 30% by mass of gas, mainly CO2). Water is then separated from the resulting reaction product slurry, yielding approximately 35% to 40% by mass of water-soluble organic matter and approximately 30% to 35% by mass of biocrude. In addition, the Cat-HTR shown in Figure 19 TM In the process, the pressure (240 atmospheres), temperature (350°C) and pressure (atmospheric pressure) when the pressure is instantly reduced in the subcritical hydrothermal treatment are not limited to those mentioned above.

[0021] The biomass used to produce the biocrude is not particularly limited, but is preferably at least one selected from the group consisting of woody biomass, herbaceous biomass, agricultural crop residue biomass, and palm biomass, and more preferably woody biomass. That is, the biocrude used as the first raw material is preferably biocrude derived from woody biomass. Biocrude has, for example, the following properties: -Contains 5% to 10% moisture by mass. Contains 5% to 15% by mass of oxygen. It contains more nitrogen than petroleum. For example, biocrude obtained from organic wet waste contains 3% to 8% nitrogen by mass. -Density is higher than crude oil.

[0022] <Biocrude hydride> The biocrude hydrogenate as the first raw material is obtained by hydrogenating biocrude. The present inventors have found that mesophase pitch having a full-surface flow structure can be obtained by subjecting the second mixed raw material obtained by the following method 1 to a co-pitching reaction. Method 1: An intermediate mixed feedstock is obtained by mixing biocrude, a second feedstock, a melt-promoting solvent, and a catalyst. The intermediate mixed feedstock is then subjected to a hydrogenation reaction to hydrogenate the biocrude in the intermediate mixed feedstock. The melt-promoting solvent and catalyst are removed from the intermediate mixed feedstock after this hydrogenation reaction. In this manner, a second mixed feedstock is obtained. Note that the second mixed feedstock obtained by Method 1 can also be called a "hydrogenated product of a mixture of biocrude and the second feedstock," since the melt-promoting solvent and catalyst have been removed from the intermediate mixed feedstock after the hydrogenation reaction.

[0023] As mentioned above, it is thought that the three-dimensional cross-linked structure of Biocrude, which is caused by ether bonds, inhibits the development of the mesophase. It is believed that by hydrogenating the biocrude using a catalyst at a relatively low temperature (e.g., 350°C), the ether bonds in the biocrude can be reduced in advance while preventing solidification. In the co-pitching step, a co-pitching reaction is carried out on a second mixed feedstock containing this biocrude hydrogenated product, and it is believed that the ether bonds in the biocrude are further reduced by hydrogen transfer from the second feedstock to the biocrude. The co-pitching reaction is preferably carried out at a temperature (e.g., 400°C) at which hydrogen transfer from the second feedstock to the biocrude is active.

[0024] <Biocrude solvent solubles> The biocrude solvent-soluble fraction can be obtained by treating the biocrude with a solvent. Hereinafter, the solvent used in the solvent treatment may be referred to as a treatment solvent. The solvent-soluble content of biocrude refers to the soluble content when biocrude is dissolved in a treatment solvent. The present inventors have found that by using a biocrude solvent-soluble component as the first feedstock, it becomes easier to obtain mesophase pitch with a full surface flow structure. The reasons for this are thought to be as follows. Conventionally, high molecular weight components such as quinoline-insoluble matter have been considered to inhibit the coalescence and growth of mesophase layers by increasing the melt viscosity of pitch or by precipitating into mesophase globules. In this embodiment, the solvent-insoluble matter is first removed from the biocrude using a treatment solvent (e.g., toluene), and the biocrude from which the solvent-insoluble matter has been removed (i.e., the biocrude solvent-soluble matter) is mixed with the second feedstock to obtain a third mixed feedstock (mixed feedstock preparation step). In the co-pitching reaction, the use of such a third mixed feedstock is believed to maintain the melt viscosity of the third mixed feedstock at an appropriate level that facilitates the coalescence and growth of mesophase layers, even at temperatures (e.g., 400°C) where hydrogen transfer from the second feedstock to the biocrude is active.

[0025] As a method for obtaining the biocrude solvent-soluble matter, known solvent treatment methods (for example, solvent extraction, heating under reduced pressure, distillation under reduced pressure, filtration, etc.) can be used. An example of the solvent extraction method is a method in which a treatment solvent is circulated using a Soxhlet extractor and solvent-soluble components are separated from the extract. Examples of processing solvents that can be used include pyridine, quinoline, tetrahydrofuran (THF), aliphatic hydrocarbons (e.g., pentane and hexane), and aromatic hydrocarbons (e.g., benzene, toluene, and xylene). These processing solvents may be used alone or in combination. Among these, aromatic hydrocarbons are preferred as the treatment solvent because they have an affinity with Biocrude and do not dissolve too much polymer, and toluene is more preferred because it has a medium dissolving power.

[0026] <Biocrude dehydrated product> In the production method according to this embodiment, the biocrude used to obtain the first mixed raw material, the biocrude used to obtain the biocrude hydrogenated product, or the biocrude used to obtain the biocrude solvent-soluble fraction is preferably a dehydrated biocrude product that has been dehydrated. The dehydrated biocrude can be obtained, for example, by heating the biocrude under reduced pressure. The dehydrated biocrude may also be obtained using a known dehydrator (e.g., a centrifugal dehydrator). The water content in the biocrude dehydrate is preferably less than 5% by mass.

[0027] [Second raw material] <Petroleum residue> In this specification, "petroleum residue" refers to a residue generated in either a petroleum refining process or a petrochemical process. "Petroleum residue having hydrogen donating ability" refers to a petroleum residue that has hydrogen donating ability. "Hydrogen donating ability" refers to the property of easily donating hydrogen to radicals. In the production method of this embodiment, the petroleum residue having hydrogen donating properties is preferably at least one selected from the group consisting of cracked residue (e.g., CLO, etc.) produced when heavy crude oil is cracked using a fluid catalytic cracking unit (FCC), vacuum-heated residue (e.g., VR, etc.) obtained by further reducing the pressure and distilling the atmospheric distillation residue of crude oil, residue (e.g., PDAS, etc.) obtained after extracting a heavy fraction (preferably a heavy fraction suitable for lubricating oil) from the vacuum-heated residue with propane, and ethylene bottom oil. FCC is an abbreviation for Fluid Catalytic Cracking. CLO is an abbreviation for Clarified Oil, also known as cracked residual oil. CLO is also commonly called decant oil and is often used in research on steel binder pitch. VR is an abbreviation for Vacuum Residue, also known as reduced pressure residue. PDAS is an abbreviation for Propane Deasphalted Asphalt, also known as propane deasphalted asphalt. Ethylene bottom oil is a liquid co-produced with ethylene by naphtha cracking, and refers to a heavy fraction having the highest boiling point among naphtha cracked fractions.

[0028] <Improved petroleum residue> The "modified petroleum residue" is preferably a residue obtained by subjecting a petroleum residue (preferably CLO) to pressure heat treatment and then heating the recovered petroleum residue under reduced pressure. The "improved product of petroleum residue" is preferably a light fraction having a softening point of 250°C or less, which is obtained by subjecting petroleum residue (preferably CLO) to pressurized heat treatment and then heating the recovered petroleum residue under reduced pressure.

[0029] Each step of the manufacturing method of this embodiment will be described.

[0030] <Mixed raw material preparation process> The mixed raw material preparation step is a step of preparing a mixed raw material (first mixed raw material, second mixed raw material, or third mixed raw material) containing a first raw material and a second raw material. The mixed raw material obtained in the mixed raw material preparation step is not particularly limited as long as it contains at least the first raw material and the second raw material. The mixing method is not particularly limited.

[0031] (First mixed raw material) A case where the first raw material is biocrude will be described. In this embodiment, the mixed raw material preparation step is preferably a step of mixing the biocrude, the second raw material, and a melt-promoting solvent that promotes the melting of the biocrude and the second raw material, thereby obtaining a first mixed raw material. Examples of the melt-promoting solvent include aliphatic hydrocarbons (e.g., pentane, hexane, etc.) and aromatic hydrocarbons (e.g., tetralin, benzene, toluene, xylene, etc.) These melt-promoting solvents may be used alone or in combination. The melt-promoting solvent is preferably an aromatic hydrocarbon, more preferably tetralin. The use of an aromatic hydrocarbon as a melt-promoting solvent promotes the hydrogen donating ability of the second feedstock and facilitates its presence in a melting range intermediate between the first and second feedstocks, thereby improving the compatibility between the first and second feedstocks.

[0032] When the mixed raw material preparation step is a step of preparing a first mixed raw material, the mixing ratio of the biocrude to the second raw material in the first mixed raw material (the first raw material / the second raw material) is preferably 100 / 200 or more and 100 / 100 or less, more preferably 100 / 200 or more and 100 / 130 or less, and even more preferably 100 / 200 or more and 100 / 150 or less, by mass. When the mixed raw material preparation step is a step of preparing a first mixed raw material, the content of the melt-promoting solvent in the first mixed raw material is preferably 650 parts by mass or more and 750 parts by mass or less per 100 parts by mass of the biocrude.

[0033] When the mixed raw material preparation step is a step of preparing a first mixed raw material, the contents of the biocrude, the second raw material, and the melt-promoting solvent in the first mixed raw material are preferably, for example, in the following ranges. The content of biocrude is preferably 4% by mass or more and 20% by mass or less, more preferably 6% by mass or more and 15% by mass or less, and even more preferably 8% by mass or more and 12% by mass or less. The content of the second raw material is preferably 10% by mass or more and 30% by mass or less, more preferably 15% by mass or more and 25% by mass or less, and even more preferably 18% by mass or more and 22% by mass or less. The content of the melt-promoting solvent is preferably 65% ​​by mass or more and 75% by mass or less. The upper limit of the total content of the biocrude, the second raw material, and the melt-promoting solvent in the first mixed raw material is 100 mass %. Note that this embodiment does not exclude the first mixed raw material containing materials other than the biocrude, the second raw material, and the melt-promoting solvent. The first mixed raw material may contain only one type of second raw material or may contain two or more types of second raw material. The first mixed raw material may contain only one type of melt-promoting solvent or may contain two or more types of melt-promoting solvent.

[0034] (Second mixed raw material) A case where the first raw material is a biocrude hydride will be described. In this embodiment, the mixed feedstock preparation step is a step of preparing a second mixed feedstock containing at least the biocrude hydride and a second feedstock. When the mixed raw material preparation step is a step of preparing a second mixed raw material, the mixed raw material preparation step preferably includes an intermediate mixed raw material preparation step of mixing the biocrude, the second raw material, a melt-promoting solvent, and a catalyst to prepare an intermediate mixed raw material, and a hydrogenation reaction step of subjecting the intermediate mixed raw material to a hydrogenation reaction to hydrogenate the biocrude into a biocrude hydride. The mixed raw material preparation step preferably further includes a removal step of removing the melt-promoting solvent and the catalyst from the intermediate mixed raw material after the hydrogenation reaction step. That is, the mixed stock preparation step preferably includes an intermediate mixed stock preparation step, a hydrogenation reaction step, and a removal step, in this order. The second mixed stock obtained in this manner is synonymous with the second mixed stock obtained by the above-mentioned method 1. The second mixed stock is obtained by removing the melt-promoting solvent and catalyst from the intermediate mixed stock after the hydrogenation reaction step, and is suitable for use in the co-pitching step. In the co-pitching process, the co-pitching reaction is carried out on the second mixed feedstock containing the biocrude hydrogenated product and the second feedstock, which is believed to further reduce the ether bonds in the biocrude, making it easier to obtain mesophase pitch with a full-surface flow structure.

[0035] (Intermediate mixed raw material preparation process) The melt-promoting solvent used in the intermediate mixed raw material preparation step is preferably an aromatic hydrocarbon, more preferably tetralin, from the viewpoint of promoting hydrogen donating to the biocrude and suppressing a decrease in the melt viscosity of the intermediate mixed raw material. As the catalyst used in the intermediate mixed material preparation step, a known hydrogenation catalyst used in a hydrogenation reaction can be used. Examples of hydrogenation catalysts include NiMo / SiO2, CoMo / Al2O3, and NiW / SiO2. NiMo / SiO2 is a catalyst in which a nickel-molybdenum catalyst is supported on a silica (SiO2) support. CoMo / Al2O3 is a catalyst in which a cobalt-molybdenum catalyst is supported on an alumina (Al2O3) support. NiW / SiO2 is a catalyst in which a nickel-tungsten catalyst is supported on a silica (SiO2) support. The content of the catalyst (hydrogenation catalyst) in the intermediate mixed raw material is preferably 30% by mass or more and 60% by mass or less relative to the biocrude. In the intermediate mixed raw material preparation step, the mixing ratio of the biocrude to the second raw material in the intermediate mixed raw material (the biocrude / the second raw material) is preferably 100 / 250 or more and 100 / 33 or less, more preferably 100 / 250 or more and 100 / 130 or less, and even more preferably 100 / 250 or more and 100 / 150 or less, by mass. The melt-promoting solvent is preferably used in an amount by mass of 2 to 3 times the total mass of the first raw material and the second raw material.

[0036] In the intermediate mixed raw material preparation step, the contents of the biocrude, the second raw material, the melt-promoting solvent, and the catalyst in the intermediate mixed raw material are preferably, for example, within the following ranges. The content of biocrude is preferably 4% by mass or more and 20% by mass or less, more preferably 6% by mass or more and 15% by mass or less, and even more preferably 8% by mass or more and 12% by mass or less. The content of the second raw material is preferably 10% by mass or more and 30% by mass or less, more preferably 15% by mass or more and 25% by mass or less, and even more preferably 18% by mass or more and 22% by mass or less. The content of the melt-promoting solvent is preferably 65% ​​by mass or more and 75% by mass or less. The catalyst content is preferably 2% by mass or more and 7% by mass or less. The upper limit of the total content of the biocrude, second raw material, melt-promoting solvent, and catalyst in the intermediate mixed raw material is 100 mass %. Note that this embodiment does not exclude the intermediate mixed raw material from containing materials other than the biocrude, second raw material, melt-promoting solvent, and catalyst. The intermediate mixed raw material may contain only one type of second raw material or may contain two or more types of second raw material. The intermediate mixed raw material may contain only one type of melt-promoting solvent or may contain two or more types of melt-promoting solvent.

[0037] (Hydrogenation reaction process) The hydrogenation reaction step is a step in which a hydrogenation reaction is carried out on the intermediate mixed feedstock to hydrogenate the biocrude into a biocrude hydride. The pressure in the hydrogenation reaction is preferably 2 MPa or more and 5 MPa or less. The temperature in the hydrogenation reaction is preferably 300°C or higher and 400°C or lower. The reaction time in the hydrogenation reaction is preferably 100 minutes or more and 150 minutes or less.

[0038] (Third mixed raw material) The case where the first raw material is a biocrude solvent-soluble matter will be described. The manufacturing method of this embodiment further includes a step of treating the biocrude with a solvent to obtain a solvent-soluble biocrude fraction prior to the mixed raw material preparation step. In this case, the mixed raw material preparation step is preferably a step of mixing the solvent-soluble biocrude fraction with the second raw material to obtain a third mixed raw material. In this way, by using the solvent-soluble components of Biocrude, the melting temperature range of the solvent-soluble components can be shifted to a higher temperature by removing the solvent-insoluble polymer components that increase the melt viscosity and cause solidification. In the co-pitching reaction, the use of this third mixed feedstock is thought to maintain the molten phase up to approximately 400°C, at which point hydrogen transfer from the hydrogen donor substance in the second feedstock to Biocrude becomes active. As a result, it becomes easier to obtain mesophase pitch with a full-surface flow structure.

[0039] In the mixed raw material preparation step, the mixing ratio of the biocrude solvent-soluble matter to the second raw material in the third mixed raw material (the biocrude solvent-soluble matter / the second raw material) is preferably 100 / 250 or more and 100 / 33 or less, more preferably 100 / 250 or more and 100 / 130 or less, and even more preferably 100 / 250 or more and 100 / 150 or less, by mass.

[0040] When the mixed raw material preparation step is a step of preparing a third mixed raw material, the contents of the biocrude solvent-soluble matter and the second raw material in the third mixed raw material are preferably, for example, in the following ranges. The content of the biocrude solvent soluble matter is preferably 20% by mass or more and 50% by mass or less, more preferably 25% by mass or more and 45% by mass or less, and even more preferably 30% by mass or more and 40% by mass or less. The content of the second raw material is preferably 50% by mass or more and 80% by mass or less, more preferably 55% by mass or more and 75% by mass or less, and even more preferably 60% by mass or more and 70% by mass or less. The upper limit of the total content of the solvent-soluble biocrude and the second raw material in the third mixed raw material is 100 mass %. Note that this embodiment does not exclude the third mixed raw material containing materials other than the solvent-soluble biocrude and the second raw material. The third mixed raw material may contain only one type of biocrude solvent-soluble component or may contain two or more types. The third mixed raw material may contain only one type of second raw material or may contain two or more types.

[0041] <Co-pitching process> The co-pitching process is a process in which a mixed feedstock (first mixed feedstock, second mixed feedstock, or third mixed feedstock) is heated under pressure (preferably under N2 pressure) to carry out a co-pitching reaction on the mixed feedstock. The pressure, temperature, temperature rise rate, reaction time, and stirring speed of the mixed raw material in the co-pitching step are preferably within the following ranges from the viewpoint of smoothly progressing the thermal reforming reaction of the mixed raw material.

[0042] ·pressure The pressure in the co-pitching step is preferably 0.5 MPa or more and 6.4 MPa or less, more preferably 1.7 MPa or more and 6.2 MPa or less, and even more preferably 3.2 MPa or more and 4.9 MPa or less.

[0043] ·temperature The temperature in the co-pitching step is preferably 260°C or higher and 450°C or lower, more preferably 270°C or higher and 430°C or lower, and even more preferably 280°C or higher and 420°C or lower.

[0044] Heating rate The temperature rise rate is preferably 5° C. / min or more and 20° C. / min or less, more preferably 5° C. / min or more and 15° C. / min or less.

[0045] Reaction time The reaction time in the co-pitching step is preferably 30 minutes or more and 6 hours or less, more preferably 60 minutes or more and 5 hours or less, and even more preferably 2 hours or more and 5 hours or less.

[0046] The co-pitching step is preferably a step of subjecting the mixed raw material to a co-pitching reaction under conditions of 0.2 MPa to 1.0 MPa, 260° C. to 450° C., and 30 minutes to 6 hours.

[0047] - Mixing speed of mixed materials The co-pitching step is preferably carried out while stirring the mixed raw materials. The stirring means is not particularly limited. The stirring speed is preferably 300 rpm or more and 1200 rpm or less, more preferably 500 rpm or more and 1200 rpm or less, and even more preferably 700 rpm or more and 1100 rpm or less.

[0048] The co-pitching step is preferably carried out under an inert gas atmosphere. Examples of the inert gas include nitrogen, helium, and argon. The inert gas may be a single gas or a mixed gas of two or more gases. Nitrogen is preferred as the inert gas.

[0049] <Pitch preparation process> The pitch preparation step is a step of preparing mesophase pitch by subjecting the reaction product obtained in the co-pitching step to a reduced pressure treatment. This pitch preparation step removes an appropriate amount of light components from the reaction product, thereby obtaining mesophase pitch. The reduced pressure treatment may be, for example, a method of heating the reaction product under reduced pressure using an evaporator (reduced pressure heating method), etc. Alternatively, the reduced pressure treatment may be a method of distilling the reaction product under reduced pressure. The pressure in the reduced pressure treatment is preferably 200 Torr or less (26664.4 Pa or less), more preferably 100 Torr or less (13332.2 Pa or less), even more preferably 50 Torr or less (6666.1 Pa or less), and even more preferably 10 Torr or less (1333.22 Pa or less). The temperature in the reduced pressure treatment is preferably 150°C or higher and 300°C or lower, and more preferably 180°C or higher and 270°C or lower. The treatment time for the reduced pressure treatment is preferably 60 minutes or more and 180 minutes or less, and more preferably 90 minutes or more and 150 minutes or less. The treatment time in the reduced pressure treatment is the holding time after the temperature in the reduced pressure treatment is reached. In the pitch preparation step, the reduced pressure treatment is preferably carried out under conditions of 200 Torr or less, 150° C. or more and 300° C. or less, and for 60 minutes or more and 180 minutes or less.

[0050] Known methods can be used for the reduced pressure heating method and reduced pressure distillation method.

[0051] (Characteristics of mesophase pitch) When the mesophase pitch prepared in the pitch preparation step was analyzed by FT-IR, the content of oxygen atoms contained in the mesophase pitch was 2.0 mass% or less, and the peak peak at 1270 cm -1 The peak of the ether bond (COC) and the peak of the ether bond (COC) at 1645 cm -1Preferably, the intensity ratio of the peak of the ether bond to the peak of the aromatic carbon skeleton (the peak of the ether bond / the peak of the aromatic carbon skeleton) is 0.45 or less. By satisfying this requirement, the biomass-derived pitch has a full-surface flow structure. The method for measuring the content of oxygen atoms contained in mesophase pitch and the intensity ratio (peak of the ether bond / peak of the aromatic carbon skeleton) will be described in the Examples section. The mesophase pitch prepared in the pitch preparation step preferably has an aromatic index fa measured by the Brown-Radner method of 0.55 or more, more preferably 0.60 or more, and even more preferably 0.65 or more. The mesophase pitch prepared in the pitch preparation step preferably has a ratio (Rn / Ra) of the number of naphthenic rings Rn to the number of aromatic rings Ra, which are monocyclic structural parameters, of 1.50 or less, more preferably 1.00 or less, and even more preferably 0.50 or less. The methods for measuring the oxygen atom content, aromatic index fa, and Rn ratio (Rn / Ra) in mesophase pitch are described in the Examples section.

[0052] Second Embodiment The manufacturing method of the second embodiment differs from the first embodiment in that it further includes a carbonization step. In other respects, it is the same as the first embodiment. In the description of the second embodiment, the description of the same components as the first embodiment will be omitted or simplified.

[0053] <Carbonization process> The carbonization step is a step of carbonizing the mesophase pitch prepared in the pitch preparation step (hereinafter also referred to as prepared pitch). The carbonization method is not particularly limited, but may be, for example, a method of heating mesophase pitch under an inert gas atmosphere, such as the inert gases listed in the section on the co-pitch formation step of the first embodiment.

[0054] The carbonization temperature, the time for which the carbonization temperature is maintained, and the temperature increase rate in the carbonization step are preferably within the following ranges, from the viewpoint of smoothly progressing the carbonization.

[0055] ·Carbonization temperature The carbonization temperature is preferably 450°C or higher and 650°C or lower, more preferably 470°C or higher and 650°C or lower, and even more preferably 500°C or higher and 650°C or lower.

[0056] Carbonization temperature holding time The carbonization temperature holding time means the holding time at the target carbonization temperature. The time for which the carbonization temperature is maintained is preferably 30 minutes or more and 4 hours or less, more preferably 30 minutes or more and 3 hours or less, and even more preferably 30 minutes or more and 2 hours or less.

[0057] Heating rate The temperature rise rate in the carbonization step is preferably 1° C. / min to 5° C. / min, more preferably 1° C. / min to 4° C. / min, and even more preferably 1° C. / min to 3° C. / min.

[0058] The carbonization step is preferably carried out under conditions where the carbonization temperature is 450° C. or higher and 650° C. or lower, and the carbonization temperature is maintained for 30 minutes or longer and 4 hours or shorter. The carbonization device is not particularly limited as long as it is capable of carbonizing mesophase pitch in a low-oxygen atmosphere (preferably in an inert gas atmosphere), and known carbonization devices can be used.

[0059] The optical texture of carbonized mesophase pitch (pitch carbide) is said to be anisotropic in the order of isotropic structure, mosaic structure, and flow structure. Table 1 shows an example of classification of optical anisotropy structures. The classification shown in Table 1 is based on the paper presented at the 16th Coal Science Conference and the 46th Joint Meeting of the Fuel Association of Japan (1979), pp. 200-206, by Isao Mochida, Shuichi Matsuoka, Keiko Maeda, et al. Mosaic and flow structures are further classified according to size. Specifically, the mosaic structure is classified into Muf, Mf, Mm, and Mc according to the diameter size of the patchy structure, with the anisotropy increasing in the order Muf, Mf, Mm, and Mc. The flow structures are classified into CF and F depending on the length of the oriented structure. The order of CF and F is increasing in anisotropy. The magnitude relationships among Muf, Mf, Mm, and Mc, as well as the magnitude relationships among CF and F, are shown in Table 1. In Table 1, I indicates an isotropic structure.

[0060] [Table 1]

[0061] [Uses of mesophase pitch and pitch carbonized material] The mesophase pitch and pitch charcoal produced by the production method of this embodiment can be used, for example, as high-performance carbon materials. Mesophase pitch can be suitably used as a high-performance carbon material, taking advantage of the high elasticity and high conductivity of its carbonized form. Examples of high-performance carbon materials include carbon materials produced from needle coke of pitch carbide (e.g., graphite electrode materials, lithium-ion battery negative electrode materials, and carbon materials for capacitors), as well as pitch used as is for carbon fiber raw material pitch and graphite electrode impregnation pitch. Examples of general-purpose carbon materials include use as binders for steel binder pitch.

[0062] (Specific example of manufacturing method 1) FIG. 16 is a block diagram showing an example of a manufacturing method according to this embodiment. FIG. 16 shows an example (Example 1) of a method for producing mesophase pitch using the first mixed raw material. The production method of Example 1 includes, in this order, a mixed raw material preparation step S10 in which a first mixed raw material is prepared by mixing a biocrude as a first raw material, a second raw material, and a melt-promoting solvent, a co-pitching step S20 in which a co-pitching reaction is carried out on the first mixed raw material, and a pitch preparation step S30 in which a reaction product obtained in the co-pitching step is subjected to a decompression treatment to prepare mesophase pitch. The production method of Example 1 further includes a carbonization step S40 in which the mesophase pitch prepared in the pitch preparation step is carbonized.

[0063] (Specific example of manufacturing method 2) FIG. 17 is a block diagram showing an example of a manufacturing method according to this embodiment. FIG. 17 shows an example (Example 2) of a method for producing mesophase pitch using the second mixed raw material. The production method according to Example 2 is the same as the production method according to Example 1, except that the mixed raw material preparation step S10 in Example 1 is replaced with a mixed raw material preparation step S11. The mixed raw material preparation step S11 includes, in this order, an intermediate mixed raw material preparation step S111 in which the biocrude, the second raw material, a melting-promoting solvent, and a catalyst are mixed to prepare an intermediate mixed raw material; a hydrogenation reaction step S112 in which the intermediate mixed raw material is subjected to a hydrogenation reaction to hydrogenate the biocrude and obtain a biocrude hydride; and a removal step S113 in which the melting-promoting solvent and catalyst are removed from the intermediate mixed raw material after the hydrogenation reaction step.

[0064] (Specific example 3 of manufacturing method steps) FIG. 18 is a block diagram showing an example of a manufacturing method according to this embodiment. FIG. 18 shows an example (Example 3) of a method for producing mesophase pitch using the third mixed raw material. The manufacturing method of Example 3 is the same as the manufacturing method of Example 1, except that the mixed raw material preparation step S10 is replaced with a mixed raw material preparation step S12, and a solvent treatment step S1 is included before the mixed raw material preparation step. The solvent treatment step S1 is a step in which the biocrude is treated with a solvent to obtain a solvent-soluble biocrude fraction prior to the mixed raw material preparation step. The mixed raw material preparation step S12 is a step of preparing a third mixed raw material containing the biocrude solvent-soluble matter as the first raw material and the second raw material. The manufacturing method according to this embodiment is not limited to the methods shown in FIGS.

[0065] Other Embodiments The carbonization step of the second embodiment may be a rapid heating carbonization step in which the mesophase pitch prepared in the pitch preparation step is rapidly heated to a carbonization temperature to carbonize it, which makes it easier to obtain mesophase pitch with a full-surface flow structure. In the rapid temperature-raising carbonization step, the temperature-raising rate is preferably 10° C. / min or more and 250° C. / min or less, more preferably 100° C. / min or more and 250° C. / min or less. The carbonization temperature and the time period for which the carbonization temperature is maintained in the rapid heating carbonization step are, for example, in the same range as the carbonization temperature and the time period for which the carbonization temperature is maintained in the carbonization step of the second embodiment.

[0066] When the carbonization step of the second embodiment is a rapid temperature-rise carbonization step, the carbonized material obtained in the rapid temperature-rise carbonization step may be further calcined at a high temperature after the rapid temperature-rise carbonization step, which makes it easier to obtain mesophase pitch with a full-surface flow structure. In the calcination step, the calcination temperature is preferably 600°C or higher and 1300°C or lower, more preferably 800°C or higher and 1200°C or lower. The calcination temperature holding time and temperature increase rate in the calcination step are, for example, in the same ranges as the carbonization temperature holding time and temperature increase rate in the carbonization step of the second embodiment.

[0067] The present invention is not limited to the above-described embodiment, and any modifications and improvements that can achieve the object of the present invention are included in the present invention. [Example]

[0068] Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0069] The co-pitching reaction of Reference Examples 1 to 3 and Example 1A is referred to as "co-pitching A", the co-pitching reaction of Examples 1B to 2B is referred to as "co-pitching B", and the co-pitching reaction of Examples 1C to 6C is referred to as "co-pitching C". In Reference Examples 1 to 3, co-pitching A was carried out on a mixed raw material containing biocrude or a dehydrated biocrude and CLO. In Example 1A, co-pitching A was carried out on a first mixed feedstock containing biocrude dehydrate, CLO, and tetralin. In Examples 1B and 1C, first, a hydrogenation reaction was carried out on an intermediate mixed feedstock containing a dehydrated biocrude, CLO, tetralin, and hydrogenation catalyst B. Then, tetralin and hydrogenation catalyst B were removed from the intermediate mixed feedstock to obtain a hydrotreated product. In Examples 1B and 1C, co-pitching B was carried out on this hydrotreated product (second mixed feedstock). In Examples 1C to 6C, the dehydrated biocrude was first extracted with toluene to obtain a toluene-soluble biocrude fraction. In Examples 1C to 6C, a third mixed material containing the toluene-soluble biocrude fraction and CLO was subjected to co-pitching C.

[0070] The raw material symbols are as follows: R: Arrival-based biocrude DR: Dehydrated Biocrude (R) obtained by heating Biocrude (R) at 0.1 kPa and 120°C for 60 minutes. TRs: Toluene-soluble fraction of dehydrated biocrude (DR) TIs: Toluene insolubles in biocrude dehydrate (DR) CLO: FCC residual oil from petroleum refining (residual oil produced when heavy crude oil is cracked using FCC)

[0071] [Co-Pitching A: Production of Mesophase Pitch and Pitch Carbonized Product] [Reference example 1] Biocrude® was used as the first raw material. Biocrude® is a biocrude with the properties shown in Table 1. CLO was used as the second raw material.

[0072] (Co-pitched A) Biocrude® (100 parts by mass) as the first raw material and CLO (100 parts by mass) as the second raw material were mixed (mixed raw material preparation step). The total amount of the mixed raw material of Biocrude® and CLO was 30 g. The mixed raw materials were placed in an autoclave (SUS, 120 mL) equipped with a stirring blade, and the atmosphere inside the autoclave was replaced with a reaction atmosphere gas (N2 gas). The system was then kept at room temperature (25°C) and the initial nitrogen pressure was set to 0.5 MPa. Next, the mixed raw material was heated to 250°C at a heating rate of 10°C / min while being stirred at 1000 rpm using a band heater, and then heated at 250°C for 4 hours to co-pitch the mixed raw material (co-pitching step). Next, the band heater was removed, and the reaction product was cooled to 60°C or less with air to degas the system.

[0073] (Pitch preparation process) Next, the reaction product was recovered from the autoclave. The recovered reaction product was placed in a Soxhlet extractor and heated under reduced pressure under the following conditions to prepare pitch (pitch preparation step). This operation removed light components from the reaction product. (conditions) ·Temperature: 230℃ Processing time: 2 hours Pressure: Less than 0.1 MPa (below the lower limit of measurement)

[0074] (carbonization process) A sample (3 g) was collected and subjected to carbonization treatment under the following carbonization condition 1 to obtain a pitch carbonized product (carbonization step). The carbonization treatment performed under the carbonization condition 1 is referred to as conventional carbonization. (Carbonization condition 1) Sample: Prepared pitch after the pitch preparation process Carbonization equipment: Standard carbonization equipment (tubular electric furnace) Carbonization method: The sample is placed on a magnetic boat in a horizontal carbonization furnace and carbonized. Heating rate: 1.5℃ / min ·Carbonization temperature: 600℃ Holding time: 2 hours Pressure: normal pressure ·Nitrogen flow rate: 200mL / min

[0075] [Reference example 2] The mesophase pitch and pitch carbonized product of Reference Example 2 were obtained in the same manner as in Reference Example 1, except that the temperature for co-pitching (250°C) was changed to 400°C in the co-pitching step.

[0076] [Reference example 3] In Reference Example 3, mesophase pitch and pitch carbonized material were obtained in the same manner as in Reference Example 2, except that the first raw material was replaced with dehydrated biocrude (DR) and the mixing ratio (DR / CLO) in the mixed raw material was changed to 100 / 200 (by mass).

[0077] Example 1A In Example 1A, a first mixed raw material was obtained by mixing 100 parts by mass of dehydrated biocrude (DR), 200 parts by mass of CLO, and 700 parts by mass of tetralin. The mesophase pitch and pitch carbonized product of Example 1A were obtained in the same manner as in Reference Example 3, except that the pitch preparation step was carried out in the following manner. The total amount of the first mixed raw material consisting of the dehydrated biocrude (DR), CLO, and tetralin was 100 g.

[0078] (Pitch preparation process) The reaction product from the co-pitching process was recovered from the autoclave. The recovered reaction product was heated to a temperature of 230°C at a temperature increase rate of 10°C / min under a pressure of less than 0.1 MPa, and then heated under reduced pressure at 230°C for 2 hours (retention time). As a result, light components and tetralin were removed from the reaction product, and mesophase pitch was prepared (pitch preparation step).

[0079] [Co-Pitching B: Production of Mesophase Pitch and Pitch Carbonized Material] Example 1B (catalytic sulfidation) A hydrogenation catalyst (NiMo / SiO2) and DMDS (dimethyl disulfide) were placed in a reaction vessel (a 500 mL Hastelloy autoclave) and treated for 2 hours under conditions of an initial hydrogen pressure of 3.0 MPa and a temperature of 300°C. After cooling to 80°C, the DMDS was removed while maintaining the temperature at 80°C. In this manner, hydrogenation catalyst B used in Example 1B was obtained.

[0080] (hydrotreating) The dehydrated biocrude (DR), CLO, tetralin, and hydrogenation catalyst B were charged in a ratio (by mass) of 100:200:700:50 into a reaction vessel (a 500 mL autoclave made of Hastelloy) (intermediate mixed raw material preparation step), and hydrogenated for 2 hours under conditions of an initial hydrogen pressure of 4.0 MPa and 350°C (hydrogenation reaction step). The total amount of the intermediate mixed raw material consisting of the dehydrated biocrude (DR), CLO, tetralin, and hydrogenation catalyst B was 120 g.

[0081] (Reactant recovery) Next, the reaction vessel was washed with the tetralin in the reaction vessel, and the solid hydrogenation catalyst B was separated using filter paper. The filtrate was then heated under reduced pressure at 90°C to remove the tetralin, thereby obtaining a hydrogenated product. In Example 1B, this hydrogenated product was used as the second mixed raw material.

[0082] (Co-pitched B) The second mixed raw material (hydrogenated product) was placed in an autoclave (120 mL, made of SUS) equipped with a stirring blade, and the atmosphere inside the autoclave was replaced with a reaction atmosphere gas (N2 gas). The system was then kept at room temperature (25°C) and the initial nitrogen pressure was set to 0.5 MPa. Next, the second mixed raw material was heated to 400°C at a heating rate of 10°C / min while being stirred at 1000 rpm using a band heater, and then heated at 400°C for 4 hours to co-pitch the second mixed raw material (co-pitching step). Next, the band heater was removed, and the reaction product was cooled to 60°C or less with air to degas the system.

[0083] (Pitch preparation process and carbonization process) The pitch preparation step and carbonization step were carried out in the same manner as in Reference Example 1. In this manner, the mesophase pitch and pitch carbonized product of Example 1B were obtained.

[0084] Example 2B In Example 2B, mesophase pitch and pitch carbonized material of Example 2B were obtained in the same manner as in Example 1B, except that the carbonization treatment was carried out under the following carbonization condition 2 (carbonization step). The pitch carbonized material of Example 2B was also used in the production of a C / C composite described below. Carbonization condition 2 also corresponds to the conventional carbonization condition. In carbonization condition 2, the temperature was raised slowly at 0.08°C / min in the range from 200°C to 550°C to suppress foaming during heating and to develop a flow structure during carbonization. (Carbonization condition 2) Sample: Prepared pitch (mesophase pitch) after the pitch preparation process Carbonization equipment: Standard carbonization equipment (tubular electric furnace) Carbonization method: The sample is placed on a magnetic boat in a horizontal carbonization furnace and carbonized. Heating rate: 1.5°C / min (however, 0.08°C / min for the range between 200°C and 550°C) ·Carbonization temperature: 600℃ Holding time: 2 hours Pressure: normal pressure ·Nitrogen flow rate: 200mL / min

[0085] [Co-Pitching C: Production of Mesophase Pitch and Pitch Carbonized Material] Example 1C (solvent extraction) Using a Soxhlet extractor, the sample was placed in a cylindrical filter paper under the following conditions, and the inside of the cylindrical filter paper was stirred and toluene (10 times the mass of the sample) was circulated while bubbling with nitrogen to extract the sample. After the extraction was completed, the extract was concentrated under reduced pressure at 120°C and less than 0.1 MPa (less than the lower limit of measurement). The concentrated fraction is called toluene soluble fraction (TRs). The thimble filter paper is dried at 80°C, and the solid residue in the filter paper is called toluene insoluble fraction (TIs). In Example 1C, this toluene soluble fraction (TRs) was used as the first raw material (solvent soluble fraction of biocrude). (Extraction conditions) Sample: Biocrude dehydrate (DR) Solvent: Toluene Extractor: Stirring Soxhlet extractor (oil bath included) Oil bath temperature: 120℃

[0086] (Co-pitched C) The toluene-soluble fraction (TRs) (100 parts by mass) as the first raw material and CLO (200 parts by mass) as the second raw material were mixed to obtain a third mixed raw material (mixed raw material preparation step). The total amount of the mixed raw material of TRs and CLO was 30 g. The third mixed raw material was placed in an autoclave (500 mL made of Hastelloy), and the atmosphere inside the autoclave was replaced with a reaction atmosphere gas (N2 gas), after which the system was kept at room temperature (25°C) and an initial nitrogen pressure of 0.5 MPa. Next, the mixed raw material was heated to 400°C at a heating rate of 10°C / min while being stirred at 1000 rpm using a band heater, and then heated at 400°C for 4 hours to co-pitch the third mixed raw material (co-pitching step). Next, the band heater was removed, and the reaction product was cooled to 60°C or less with air to degas the system.

[0087] (Pitch preparation process and carbonization process) The pitch preparation step and carbonization step were carried out in the same manner as in Reference Example 1. In this manner, the mesophase pitch and pitch carbonized product of Example 1C were obtained.

[0088] Example 2C The mesophase pitch and pitch carbonized product of Example 2C were obtained in the same manner as in Example 1C, except that the carbonization step was carried out under the following carbonization condition 3. Carbonization condition 3 is referred to as rapid temperature rise carbonization condition. (Carbonization condition 3) Sample: Prepared pitch (mesophase pitch) after the pitch preparation process Carbonization equipment: Rapid heating carbonization equipment (autoclave-type tubing bomb and salt bath furnace (constant temperature of 500°C)) Carbonization method: The sample is wrapped in aluminum foil and loaded into a tubing bomb reactor. The tubing bomb reactor containing the sample is directly immersed in molten salt in a salt bath furnace at 500°C, and carbonization is carried out under pressure by rapidly increasing the temperature while maintaining a pressure of 1.5 MPa using the release valve. Heating rate: 500℃ / 2 minutes ·Carbonization temperature: 500℃ Holding time: 4 hours Pressure: 1.5MPa

[0089] Example 3C The mesophase pitch and pitch charcoal of Example 3C were obtained in the same manner as in Example 2C, except that a calcination step was carried out under the following calcination conditions after the carbonization step of Example 2C. The pitch charcoal of Example 3C was also used to produce graphite electrode samples described below. (Caloning conditions) Sample: Carbonized material after carbonization process Carbonization equipment: tubular electric furnace Carbonization method: The sample is placed on a magnetic boat in a horizontal carbonization furnace and carbonized. ·Nitrogen flow rate: 200mL / min Heating rate: 5.0℃ / min Heat treatment conditions: 1000℃ Holding time: 1 hour Pressure: normal pressure

[0090] Example 4C In Example 4C, the mesophase pitch and pitch carbonized product of Example 4C were obtained in the same manner as in Example 1C, except that the mixing ratio (TRs / CLO) in the third mixed raw material was changed to 100 / 100 (by mass).

[0091] Example 5C In Example 5C, the mesophase pitch and pitch carbonized product of Example 5C were obtained in the same manner as in Example 1C, except that the mixing ratio (TRs / CLO) in the third mixed raw material was changed to 100 / 150.

[0092] Example 6C The mesophase pitch and pitch carbonized product of Example 6C were obtained in the same manner as in Example 5C, except that the carbonization step was carried out under the above-mentioned carbonization condition 3 (rapid temperature rise carbonization condition).

[0093] 〔evaluation〕 The following evaluations were carried out, and the results are shown in Table 2. Hereinafter, mesophase pitch may be simply referred to as pitch.

[0094] <Pitch yield, carbonization yield, and total carbonization yield> The pitch yield, carbonization yield, and total carbonization yield were determined. Table 2 also shows the carbonization yields and overall carbonization yields of the first raw materials (R, DR, and TRs), the second raw material (CLO), and the TIs. The first raw material, the second raw material, and the TIs were carbonized according to the methods described in Table 2.

[0095] The overall carbonization yield was calculated by the following formula (10). Total carbonization yield = (pitch yield × carbonization yield) / 100 (10)

[0096] Pitch yield (Y p ) and carbonization yield (based on pitch) (Y1) were calculated by the following method. All yields were calculated excluding ash. p ) and carbonization yield (based on pitch) (Y1) are yields on an ash-free basis.

[0097] [Measurement of ash content] The ash content of the raw material, pitch, and pitch carbonized product was measured under the following conditions: The ash content on a dry mass basis was calculated using the following formula (11). Ash content based on dry mass [wt%] = W ash / W dry ×100…(11) W dry :120℃ dry mass [g] W ash : Combustion ash mass [g]

[0098] (conditions) Apparatus: Differential thermobalance TG-DTA (manufactured by Mac Science) Atmosphere: Air, 200 mL / min ·120℃ dry mass W dry Temperature conditions Heating rate: 10°C / min, from room temperature (25°C) to 120°C Holding time: 120℃, 20min Combustion ash mass W ash Temperature conditions Heating rate: 10°C / min, from 120°C to 950°C

[0099] Pitch yield (Y p ) Pitch yield (Y p ) was calculated using formula (12). Y P (wt%)={W2*(100-A P ) / 100} / {W1*(100-A0) / 100}…(12) W1: Amount of raw material input (g) W2: Pitch yield (g) A0: Ash content of raw material (wt%) A P : Ash content of pitch (wt%)

[0100] [Carbonization yield (based on pitch) (Y1)] The carbonization yield (Y1) was calculated using formula (13). Y1(wt%)={Wc*(100-A C ) / 100} / {W P *(100-A P ) / 100}…(13) W P : Mass of pitch before carbonization (g) W C : Mass of pitch carbide (g) A P : Ash content of pitch (wt%) A C : Ash content of pitch carbonized material (wt%)

[0101] <Structural analysis> (Aromatic index fa, number of aromatic rings Ra, number of naphthenic rings Rn, and ratio Rn / Ra) The aromatic index fa, the number of aromatic rings Ra, the number of naphthenic rings Rn, and the ratio of the number of naphthenic rings to the number of aromatic rings (Rn / Ra) of the pitch were calculated using the Brown-Ladner method (hereinafter also referred to as the BL method). The same calculations were performed for the R and CLO chars. Table 2 shows the aromatic index fa and the ratio (Rn / Ra). As can be seen from Table 2, the prepared pitches of Example 1A, Examples 1B to 2B, Example 1C, and Example 3C exhibited higher aromatic index fa values ​​than Biocrude® and carbonized CLO.

[0102] <Optical structure of pitch carbide> The pitch carbide or the carbide of the first raw material was observed using a polarizing microscope (DM2700P, manufactured by Leica Microsystems) by the following method. A 0.5 g sample was taken from the pitch carbonized product or the carbonized product of the first raw material obtained in each example, and the sample was covered with resin, which was then polished off to prepare a sample for microscopic observation. The polarizing microscope was set in a crossed Nicol position, and a quartz test plate was inserted to observe the sample for microscopic observation.

[0103] [Table 2]

[0104] FIG. 1 shows a polarizing microscope photograph of the carbide of the first raw material (DR). FIG. 2 shows a polarizing microscope photograph of the carbides of the first raw material (TRs). FIG. 3 shows a polarizing microscope photograph of the carbide of the second raw material (CLO). 4 to 12 show polarizing microscope photographs of the pitch carbides of Reference Examples 1 to 3 and Examples 1A, 1B, 1C, 3C, 5C and 6C.

[0105] As shown in Figures 1 and 2, all of the DR and TRs pure carbides had an isotropic structure. The overall carbonization yield was 39.8% for DR and 22.4% for TRs. Both were relatively high. As shown in Figure 3, the carbonized CLO had a full-flow structure. The overall carbonization yield was extremely low at 1.4%.

[0106] 4, the pitch charcoal obtained in Reference Example 1 had an isotropic structure, and the overall carbonization yield was 18.2%. As shown in Figure 5, the pitch carbonized product of Reference Example 2 had a mosaic structure. Due to the effect of hydrogen transfer from CLO, a mosaic structure appeared all over the biocrude, which is a biomass raw material. The overall carbonization yield reached 30.9%. As shown in Figure 6, the pitch charcoal of Reference Example 3 had a mosaic structure with a partially flowing structure. It is assumed that hydrogen migration was enhanced by doubling the amount of CLO. The overall carbonization yield was 27.0%. As shown in Figure 7, the pitch carbonized material of Example 1A had a mixture of flow structure and mosaic structure, and had an optical structure with a larger size than the pitch carbonized material of Reference Example 3, which did not use tetralin (an example of a melt-promoting solvent). Since almost all of the tetralin was recovered, it is thought that it contributed to a decrease in the melt viscosity of the system as a solvate. On the other hand, the overall carbonization yield was 3.7%, which was a small yield among co-pitching. Since tetralin is a hydrogen donor substance, it is possible that hydrogen transfer from tetralin to biocrude promoted the depolymerization of the compound. As shown in Figure 8, the pitch carbonized product of Example 1B had a full-surface flow structure, and the overall carbonization yield was low at 9.6%. 9, the pitch carbonized product of Example 1C had a full flow structure. The overall carbonization yield was 20.7%. Despite the full flow structure, the overall carbonization yield remained in the 20% range. The production method of Example 1C can be said to be a method in which the hydrogenation of DR in Example 1B is replaced with solvent extraction of DR as a pretreatment of biocrude, and therefore the production method of Example 1C can contribute to simplification of the process and reduction of equipment costs. As shown in Figure 10, the pitch carbonized product of Example 3C had a full-surface flow structure similar to that of Example 1C (conventional carbonization method). The overall carbonization yield was 41.2%, which was double that of Example 1C. The rapid heating carbonization method enabled the carbonization yield to be increased while maintaining the carbon quality. As shown in FIG. 11, the pitch carbide of Example 5C remained in a partial flow structure because the amount of CLO was reduced to 1.5 times that of Example 1C. As shown in Figure 12, the pitch carbonized product of Example 6C exhibited a full flow structure even when the amount of CLO was reduced to 1.5 times that of Example 1C by the rapid temperature rise carbonization method. Furthermore, the overall carbonization yield of Example 6C was 27%. The rapid temperature rise carbonization method was found to be an effective method for developing a flow structure.

[0107] <Evaluation of graphite material applications> Using the flow-structured pitch carbides of Example 2B and Example 3C as raw materials, two types of molded products (C / C composite and graphite electrode sample) were produced. The resulting molded products were each graphitized to produce graphitized products, which were then analyzed by XRD. The degree of graphitization of the graphitized products was calculated and used as an index of their usability as graphite materials.

[0108] (C / C composite manufacturing) A C / C composite was produced by the following method: The prepared pitch of Example 2B was used as a binder (hereinafter referred to as binder B).

[0109] (1-1) Preparation of aggregate The pitch (10 g) prepared in Example 2B was subjected to a carbonization treatment to obtain pitch charcoal, which was used as aggregate.

[0110] (1-2) C / C composite molding The obtained aggregate (80 parts by mass), binder B (20 parts by mass), and 10 mL of chloroform were placed in an agate mortar. The aggregate and binder B were kneaded and stirred in the chloroform to blend them, and then the chloroform was removed by drying under reduced pressure. Next, the mixture of aggregate and binder B was placed in a mold and molded using a heat press. The temperature of heaters installed above and below the mold was set to 170°C, and after the surface temperature at the center of the mold body reached 140°C, the mixture was compressed at 30 MPa and heated for 5 minutes. The mixture was then left to cool naturally overnight while still compressed.

[0111] (1-3) Calcination of C / C composite The removed C / C composite was calcined at 800°C. As in carbonization condition 2, the temperature was increased slowly from 250°C to 550°C at a rate of 0.08°C / min.

[0112] (1-4) Graphitization of C / C composites The calcined C / C composite was placed in an 80 mm high graphite crucible, covered with a lid, and graphitized at 2800°C under an Ar gas flow under the following conditions: The detailed temperature and atmosphere conditions are as follows: (Graphitization treatment conditions) Temperature conditions: The temperature was increased from room temperature to 800°C at a rate of 25°C / min, then increased from 800°C to 2800°C at a rate of 5°C / min, and held at 2800°C for 30 minutes. The temperature was then decreased at a rate of 10°C / min. Atmosphere: Argon atmosphere (After the pressure in the crucible was reduced to a medium vacuum, the pressure was restored with argon gas. The argon flow rate was 1 L / min during the graphitization treatment.)

[0113] (1-5) Properties of graphitized C / C composites The graphitized C / C composite was a dense and hard compact (density 1.29 g / cm 3 ). A polarized light microscope photograph of the graphitized C / C composite is shown in Fig. 13. In the microscope photograph, the composite particles had developed into large flow structures, and the low-magnification image revealed that the individual particles were not oriented in the same direction.

[0114] (Production of graphite electrode samples) Using the calcined pitch charcoal of Example 3C (hereinafter sometimes referred to as calcined needle coke (NC)), a graphite electrode sample was produced by the following method. Calcined needle coke (NC) was crushed, and binder C prepared by the following method was added. After molding, the mixture was impregnated with impregnation pitch and graphitized at 2800°C. Preparation of binder C The reaction product obtained in the co-pitch formation step of Example 1C was heated under reduced pressure (less than 0.1 MPa) at 230°C (heating rate 10°C / min) for 3 hours (holding time). By heating under reduced pressure for a longer period than in the pitch preparation step of Example 1C, light components were further removed, and a prepared pitch with a softening point of 107°C was obtained. This was used as binder C. The softening point of the prepared pitch used as binder C was determined with reference to data on pitches actually used.

[0115] (2-1) Preparation of electrode aggregate Calcined needle coke (NC) was crushed and classified to the following particle size ratio (total ratio 100 wt%), which was used as electrode aggregate. (particle size) 16mesh to 60mesh particle size: 20wt% 60mesh to 200mesh particle size: 45wt% Particle size less than 200 mesh: 35wt%

[0116] (2-2) Filling the electrode aggregate into the mold Binder C (35 wt%, 4.6 g) was mixed with the electrode aggregate and slurried with chloroform. The slurried mixture (hereinafter referred to as the sample) was dried at 80 °C and then dried again under reduced pressure to blend the binder C into the electrode aggregate (NC). The dried sample was then filled into a 1.5 × 1.5 × 6.0 cm mold.

[0117] (2-3) Molding of electrode skeleton The top and bottom surfaces were heated to 150°C using a heat press, and the mold body was also heated to 150°C using a ribbon heater and held for 10 minutes, after which the top, bottom, and mold were heated to 180°C. 10 minutes after the temperature had stabilized, the sample was pressed all at once to 10 MPa, and then allowed to cool and release pressure naturally with the ribbon heater still wrapped around it. After cooling, the sample inside the press was removed using an extraction tool. The pressure was set to 10 MPa to make removal easier.

[0118] (2-4) Carbonization of the molded electrode skeleton The molded product was heated slowly at a rate of 0.08°C / min from 140°C to 600°C, and then 1.5°C / min thereafter, and then treated at 1000°C for 1 hour to obtain an electrode skeleton.

[0119] (2-5) Pitch impregnation treatment of the molded electrode skeleton The reaction product obtained in the co-pitching step of Example 1C was heated under reduced pressure (less than 0.1 MPa) at 230°C (heating rate: 10°C / min) for 2.5 hours (holding time). This resulted in a prepared pitch with a softening point of 83°C. This was used as the pitch for impregnation. The softening point of the prepared pitch used as the impregnation pitch was determined with reference to data on pitches that are actually used. To increase the density of the formed electrode skeleton, the electrode was impregnated twice with impregnation pitch.

[0120] (First impregnation treatment) 15 g of impregnation pitch was added to an autoclave vessel with an inner diameter of 4 cm. An additional 50 g or more of impregnation pitch was added to the electrode skeleton so that the skeleton was buried in the pitch when melted. For impregnation, the container was covered and the pressure was reduced using a vacuum pump at room temperature until it reached less than 0.1 MPa (below the lower limit of measurement), after which the pressure was reduced for 2 hours. Heating began under reduced pressure and the container was heated until the external temperature reached 210°C. The container was then pressurized to 1 MPa with nitrogen and heated for 30 minutes. The pressure was adjusted to 1 MPa during heating. After 30 minutes, the pressure was released and the container was cooled until the external temperature reached 130°C. The container was then replaced with argon gas, and the container was opened while the gas was flowing. The impregnated sample was then recovered. The recovered sample was placed in a beaker in an argon gas atmosphere and allowed to cool.

[0121] (Second impregnation treatment) A second impregnation treatment was carried out using impregnation pitch in the same manner as the first impregnation treatment.

[0122] (2-6) Calcination after pitch impregnation After two impregnation treatments, the impregnated sample was heated from 140 to 600°C at a rate of 0.08°C / min, then slowly heated to 1000°C at 1.5°C / min, and treated at 1000°C for 1 hour.

[0123] (2-7) Graphitization treatment The electrode skeleton calcined after the second impregnation treatment was placed in an 80 mm high graphite crucible, which was then covered with a lid and graphitized at 2800°C under an Ar gas flow to obtain a graphite electrode sample. The detailed temperature and atmosphere conditions are as follows: (Graphitization treatment conditions) Temperature conditions: The temperature was increased from room temperature to 800°C at a rate of 25°C / min, then increased from 800°C to 2800°C at a rate of 5°C / min, and held at 2800°C for 30 minutes. The temperature was then decreased at a rate of 10°C / min. Atmosphere: Argon atmosphere (The pressure in the crucible was reduced and then restored with argon gas. The argon flow rate was 1 L / min during the graphitization treatment.)

[0124] (2-8) Properties of graphite electrode samples The graphite electrode sample was a dense and hard compact. A polarizing microscope photograph of the graphite electrode sample is shown in FIG. As shown in Figure 14, the carbonaceous material itself developed a large flow structure with good quality from all directions.

[0125] (Evaluation by X-ray diffraction analysis of C / C composite and graphite electrode samples) The degree of graphitization, crystallite size, lattice constant, and average interplanar spacing of the C / C composite and graphite electrode samples were calculated using XRD (X-ray Diffraction Analysis). The degree of graphitization, crystallite size, and average interplanar spacing are indicators of the graphite crystal structure. Degree of graphitization P I d 002 The values ​​were calculated using the following mathematical formula (1) proposed by BE Warren et al. For XRD, a SmartLab manufactured by Rigaku Corporation was used. The results are shown in Table 3.

[0126]

number

[0127] [Table 3]

[0128] The C / C composite and graphite electrode samples produced from the two types of pitch respectively had high-grade graphite structures in terms of graphitization degree, crystallite size, and average interplanar spacing, confirming their potential as graphite electrode materials.

[0129] <FT-IR analysis of pitch> The prepared pitches obtained in Reference Examples 1 to 3, Examples 1A, 1B, 2B, and 1C after the pitch preparation process, the first raw materials (R, DR, TRs), and the second raw material (CLO) were analyzed by FT-IR. The results are shown in Table 4. (Analysis conditions) ·Equipment used: Thermo Fisher Scientific Nicolet iS50 FT-IR Measurement method: Diffuse reflection method ·Resolution: 4cm-1 Accumulation count: 128 times Detector: DTGS

[0130] [Table 4]

[0131] FT-IR charts of the prepared pitches produced in Reference Example 1, Reference Example 3, Example 1A, and Example 1B, as well as DR and CLO, are shown in FIG. Furthermore, the results of characterization of the optical structure according to the ether bond and oxygen content in the pitch are shown in Figure 21. In Figure 21, the horizontal axis "oxygen atom content (mass%) contained in pitch, etc." is synonymous with "oxygen (mass%, daf)" in Table 4. The oxygen atom content (mass%) was determined by the difference in elemental analysis (C, H, N, S). In Figure 21, the vertical axis "ether bond intensity ratio" is the intensity ratio of 1270 cm in Table 4. -1 The peak of the ether bond (COC) and the peak of the ether bond (COC) at 1645 cm -1 The intensity ratio is the intensity ratio of the ether bond peak to the aromatic carbon skeleton peak (the ether bond peak / the aromatic carbon skeleton peak). The intensity ratio was determined by analyzing the FT-IR peak ratio as shown in FIG. 20 above. As shown in FIG. 20, the oxygen-containing groups (alcohol OH: 3333 cm) contained in the prepared pitches produced in Reference Example 1, Reference Example 3, Example 1A, and Example 1B were -1 , carbonyl C=O: 1697cm -1 and ether COC: 1270 cm -1 ) is reduced compared to the oxygen-containing group contained in DR as the first raw material. In addition, CLO, which contains almost no oxygen, hardly exhibited any peaks of oxygen-containing alcohol groups or oxygen-containing carbonyl groups. Furthermore, as shown in Figure 21, characterization of the optical structure based on the ether bond and oxygen content in the pitch reveals that the requirements for biomass-derived pitch to have a full-surface flow structure are that the "oxygen atom content (mass%) in the pitch" is 2.0 mass% or less and the "ether bond intensity ratio" is 0.45 or less, which can serve as important indicators.

[0132] <Effects of rapid heating and carbonization> 9, 11 and 12 are polarized light microscope photographs of the pitch carbides of Examples 1C, 5C and 6C, respectively, and FIG. 15 is a polarized light microscope photograph of the pitch carbide of Example 2C. The pitch carbonized material of Example 1C, which was carbonized by conventional carbonization, is compared with the pitch carbonized material of Example 2C, which was carbonized by rapid heating carbonization. As can be seen from Table 2, Example 2C had higher carbonization yield and overall carbonization yield than Example 1C. Furthermore, comparing the micrographs at the same magnification in Figures 9 and 15, it can be seen that although both have a full-surface flow structure, Example 2C, which underwent rapid temperature-raising carbonization, has a larger flow structure in width and length. Similarly, the pitch carbonized material of Example 5C, which was carbonized by conventional carbonization, is compared with the pitch carbonized material of Example 6C, which was carbonized by rapid heating carbonization. As can be seen from Table 2, Example 6C had higher carbonization yield and overall carbonization yield than Example 5C. Furthermore, in Figures 11 and 12, the pitch carbonized product of Example 5C, which was carbonized by conventional method, was a carbonized product mainly having a mosaic structure, while the pitch carbonized product of Example 6C, which was carbonized by rapid heating, was a carbonized product with a full-surface flow structure. Therefore, the rapid heating carbonization method was found to be an effective method for improving both the quantity (carbonization yield) and quality (optical structure of carbon) of char. [Industrial Applicability]

[0133] The mesophase pitch and pitch carbonized material produced by the production method of the present invention can be used as high-performance carbon materials, etc., and therefore the production method of the present invention has industrial applicability.

Claims

1. A method for producing mesophase pitch from a biomass-derived raw material, comprising: A first feedstock is a biocrude, a biocrude hydrogenate obtained by hydrogenating the biocrude, or a biocrude solvent-soluble fraction obtained by solvent-treating the biocrude, and a second feedstock is at least one selected from the group consisting of a petroleum residue having hydrogen donating properties and a modified product of the petroleum residue, a mixed raw material preparation step of preparing a mixed raw material containing at least the first raw material and the second raw material; a co-pitching step of heating the mixed raw material under pressure to carry out a co-pitching reaction on the mixed raw material; and a pitch preparation step of preparing mesophase pitch by subjecting the reaction product obtained in the co-pitching step to reduced pressure; The mixed raw material is a first mixed raw material containing the biocrude, the second raw material, and a melting-promoting solvent that promotes the melting of the biocrude and the second raw material; a second mixed feed comprising the biocrude hydride and the second feed; or A third mixed raw material containing the biocrude solvent-soluble component and the second raw material; A method for producing mesophase pitch.

2. The co-pitching step is a step of subjecting the mixed raw material to the co-pitching reaction under conditions of 0.2 MPa or more and 1.0 MPa or less, 260 ° C or more and 450 ° C or less, and 30 minutes to 6 hours or less. The method for producing the mesophase pitch according to claim 1.

3. The mixed raw material preparation step is a step of mixing the biocrude, the second raw material, and the melt-promoting solvent. A method for producing the mesophase pitch according to claim 1 or claim 2.

4. In the mixed raw material preparation step, a mixing ratio of the biocrude to the second raw material in the first mixed raw material (the biocrude / the second raw material) is 100 / 200 or more and 100 / 100 or less by mass; The content of the melt-promoting solvent in the first mixed raw material is 650 parts by mass or more and 750 parts by mass or less with respect to 100 parts by mass of the biocrude. The method for producing the mesophase pitch according to claim 3.

5. The mixed raw material preparation step includes an intermediate mixed raw material preparation step of mixing the biocrude, the second raw material, the melt-promoting solvent, and a catalyst to prepare an intermediate mixed raw material; a hydrogenation reaction step of subjecting the intermediate mixed feedstock to a hydrogenation reaction to hydrogenate the biocrude to obtain the biocrude hydrogenated product; A method for producing the mesophase pitch according to claim 1 or claim 2.

6. The mixed raw material preparation step includes a removal step of removing the melt-promoting solvent and the catalyst from the intermediate mixed raw material after the hydrogenation reaction step. The method for producing the mesophase pitch according to claim 5.

7. In the intermediate mixed raw material preparation step, a mixing ratio of the biocrude to the second raw material (the biocrude / the second raw material) in the intermediate mixed raw material is 100 / 250 or more and 100 / 33 or less by mass. The method for producing the mesophase pitch according to claim 5.

8. The method further includes a solvent treatment step of treating the biocrude with a solvent to obtain a biocrude solvent-soluble fraction before the mixed raw material preparation step, The mixed raw material preparation step is a step of obtaining the third mixed raw material by mixing the biocrude solvent-soluble component and the second raw material. A method for producing the mesophase pitch according to claim 1 or claim 2.

9. In the mixed raw material preparation step, the mixing ratio of the biocrude solvent-soluble matter to the second raw material in the third mixed raw material (the biocrude solvent-soluble matter / the second raw material) is 100 / 250 or more and 100 / 33 or less by mass. The method for producing the mesophase pitch according to claim 8.

10. The biocrude used when obtaining the first mixed raw material, the biocrude used when obtaining the biocrude hydrogenated product, or the biocrude used when obtaining the biocrude solvent-soluble fraction is a biocrude dehydrate that has been dehydrated. A method for producing the mesophase pitch according to claim 1 or claim 2.

11. The co-pitching step is carried out while stirring the mixed raw material. A method for producing the mesophase pitch according to claim 1 or claim 2.

12. The method further includes a carbonization step of carbonizing the mesophase pitch prepared in the pitch preparation step. A method for producing the mesophase pitch according to claim 1 or claim 2.

13. The carbonization step is carried out under the conditions of a carbonization temperature of 450°C or higher and 650°C or lower, and a holding time at the carbonization temperature of 30 minutes or higher and 4 hours or lower. The method for producing the mesophase pitch according to claim 12.

14. The petroleum residue is at least one selected from the group consisting of cracked residue produced when heavy crude oil is cracked using a fluid catalytic cracking unit, vacuum-heated residue obtained by further reducing the pressure of atmospheric distillation residue of crude oil and distilling it, residue obtained after extracting a heavy fraction from the vacuum-heated residue with propane, and ethylene bottom oil. A method for producing the mesophase pitch according to claim 1 or claim 2.

15. When the mesophase pitch prepared in the pitch preparation step was analyzed by FT-IR, The content of oxygen atoms contained in the mesophase pitch is 2.0% by mass or less, 1270 cm －１ and a peak of an ether bond (C—O—C) at 1645 cm －１ the intensity ratio of the peak of the ether bond to the peak of the aromatic carbon skeleton (the peak of the ether bond / the peak of the aromatic carbon skeleton) is 0.45 or less; A method for producing the mesophase pitch according to claim 1 or claim 2.

Images