JP2024020905A - Production method of petroleum-based pitch - Google Patents
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- 239000011301 petroleum pitch Substances 0.000 title claims abstract description 38
- 238000004519 manufacturing process Methods 0.000 title claims description 33
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 42
- WFPZPJSADLPSON-UHFFFAOYSA-N dinitrogen tetraoxide Chemical compound [O-][N+](=O)[N+]([O-])=O WFPZPJSADLPSON-UHFFFAOYSA-N 0.000 claims abstract description 42
- 238000006396 nitration reaction Methods 0.000 claims abstract description 40
- 239000003208 petroleum Substances 0.000 claims abstract description 39
- 239000000295 fuel oil Substances 0.000 claims abstract description 34
- 238000009835 boiling Methods 0.000 claims abstract description 28
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 25
- 239000003575 carbonaceous material Substances 0.000 claims abstract description 25
- 239000003921 oil Substances 0.000 claims description 45
- 238000000034 method Methods 0.000 claims description 41
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims description 29
- 239000005977 Ethylene Substances 0.000 claims description 29
- 239000011305 binder pitch Substances 0.000 claims description 19
- 229910002804 graphite Inorganic materials 0.000 claims description 17
- 239000010439 graphite Substances 0.000 claims description 17
- 239000003795 chemical substances by application Substances 0.000 claims description 5
- 230000000802 nitrating effect Effects 0.000 claims description 3
- 150000002823 nitrates Chemical class 0.000 claims description 2
- 238000004821 distillation Methods 0.000 abstract description 25
- 239000011295 pitch Substances 0.000 description 38
- 238000010438 heat treatment Methods 0.000 description 18
- 238000010304 firing Methods 0.000 description 14
- 239000011271 tar pitch Substances 0.000 description 11
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 9
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 9
- 239000007789 gas Substances 0.000 description 9
- 238000004898 kneading Methods 0.000 description 9
- 239000002904 solvent Substances 0.000 description 9
- 239000000126 substance Substances 0.000 description 8
- 239000011269 tar Substances 0.000 description 8
- WHRZCXAVMTUTDD-UHFFFAOYSA-N 1h-furo[2,3-d]pyrimidin-2-one Chemical compound N1C(=O)N=C2OC=CC2=C1 WHRZCXAVMTUTDD-UHFFFAOYSA-N 0.000 description 7
- 235000006173 Larrea tridentata Nutrition 0.000 description 7
- 244000073231 Larrea tridentata Species 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 7
- 229960002126 creosote Drugs 0.000 description 7
- 239000000047 product Substances 0.000 description 7
- 239000000463 material Substances 0.000 description 6
- 239000011521 glass Substances 0.000 description 5
- 238000005087 graphitization Methods 0.000 description 5
- 238000005470 impregnation Methods 0.000 description 5
- 238000000465 moulding Methods 0.000 description 5
- 239000011148 porous material Substances 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- SMWDFEZZVXVKRB-UHFFFAOYSA-N Quinoline Chemical compound N1=CC=CC2=CC=CC=C21 SMWDFEZZVXVKRB-UHFFFAOYSA-N 0.000 description 4
- 238000004231 fluid catalytic cracking Methods 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 230000001590 oxidative effect Effects 0.000 description 4
- 238000010998 test method Methods 0.000 description 4
- 238000005979 thermal decomposition reaction Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 3
- 241000196324 Embryophyta Species 0.000 description 3
- 238000004566 IR spectroscopy Methods 0.000 description 3
- 239000000571 coke Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 238000001125 extrusion Methods 0.000 description 3
- 239000011331 needle coke Substances 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 238000005292 vacuum distillation Methods 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 description 2
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- 150000001335 aliphatic alkanes Chemical class 0.000 description 2
- 150000001336 alkenes Chemical class 0.000 description 2
- 150000001491 aromatic compounds Chemical class 0.000 description 2
- 239000012298 atmosphere Substances 0.000 description 2
- 239000006229 carbon black Substances 0.000 description 2
- 239000011294 coal tar pitch Substances 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- -1 ethylene, propylene Chemical group 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 125000000449 nitro group Chemical group [O-][N+](*)=O 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000001007 puffing effect Effects 0.000 description 2
- 238000000197 pyrolysis Methods 0.000 description 2
- 238000004227 thermal cracking Methods 0.000 description 2
- 238000002303 thermal reforming Methods 0.000 description 2
- MGWGWNFMUOTEHG-UHFFFAOYSA-N 4-(3,5-dimethylphenyl)-1,3-thiazol-2-amine Chemical compound CC1=CC(C)=CC(C=2N=C(N)SC=2)=C1 MGWGWNFMUOTEHG-UHFFFAOYSA-N 0.000 description 1
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 229910003481 amorphous carbon Inorganic materials 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 239000011280 coal tar Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 238000000921 elemental analysis Methods 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000003502 gasoline Substances 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 229910000856 hastalloy Inorganic materials 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000003350 kerosene Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 125000004433 nitrogen atom Chemical group N* 0.000 description 1
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000006068 polycondensation reaction Methods 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
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- 238000003756 stirring Methods 0.000 description 1
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- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 239000003039 volatile agent Substances 0.000 description 1
- 239000008096 xylene Substances 0.000 description 1
Landscapes
- Working-Up Tar And Pitch (AREA)
Abstract
Description
本発明は、黒鉛電極等の炭素材の製造に用いられる石油系ピッチの製造方法に関するものである。 The present invention relates to a method for producing petroleum-based pitch used in producing carbon materials such as graphite electrodes.
鉄の再融解を行う電気炉で用いられる黒鉛電極等の炭素材は、コークスなどの骨材とピッチ（「バインダーピッチ」という）とをバインダーピッチの軟化点以上の温度で混練・成形した後に焼成し、次いで黒鉛化することで製造される。炭素材は、機械的強度が高いこと、電気伝導度及び熱伝導度が高いことなどの特性が要求されるため、炭素材は高密度であることが好ましい。しかし、通常は、焼成工程においてバインダーピッチ中の低分子量成分が揮発することなどに由来し、焼成体は気孔の多い構造となる。そのため、製造工程の中で焼成体へのピッチ（「含浸ピッチ」という）の含浸と再焼成を数回行うことで気孔率を低減し、得られる炭素材を高密度にしている。したがって、炭素材の製造に用いられるピッチは、その目的から、コークスとの混練が容易になるように低軟化点を有し、かつ、炭素材の密度が高くなるように高固定炭素量を有することが求められる。 Carbon materials such as graphite electrodes used in electric furnaces that remelt iron are made by kneading and forming aggregates such as coke and pitch (referred to as "binder pitch") at a temperature above the softening point of the binder pitch, and then firing. It is then produced by graphitizing. Since the carbon material is required to have characteristics such as high mechanical strength, high electrical conductivity, and high thermal conductivity, it is preferable that the carbon material has high density. However, the fired product usually has a structure with many pores due to the volatilization of low molecular weight components in the binder pitch during the firing process. Therefore, during the manufacturing process, the fired body is impregnated with pitch (referred to as "impregnated pitch") and re-fired several times to reduce the porosity and increase the density of the resulting carbon material. Therefore, pitch used in the production of carbon materials has a low softening point so that it can be easily kneaded with coke, and a high fixed carbon content so that the density of the carbon material is high. That is required.
ナフサ等の石油系炭化水素を水蒸気分解又は熱分解してエチレン、プロピレン等のオレフィンを製造する際に副生する重質残渣油（エチレンボトム油）は、一部がカーボンブラックの原料として利用されるのみで、大部分は燃料として利用されている。そのため、このエチレンボトム油を付加価値の高い製品に転換することは当該技術分野の課題である。この課題を解決するために、芳香族化合物を多く含有するエチレンボトム油の特性を活かし、エチレンボトム油から炭素材製造用バインダーピッチを製造する試みがなされてきた。しかし、エチレンボトム油等の石油系重質油から製造される石油系ピッチは、石炭系重質油から得られるコールタールピッチに比べて固定炭素量が低いため、得られる炭素材の密度が低くなる傾向にある。したがって、バインダーピッチや含浸ピッチには、主にコールタールピッチが使われているのが現状である。 Some of the heavy residual oil (ethylene bottom oil) that is produced as a by-product when producing olefins such as ethylene and propylene by steam cracking or thermal cracking of petroleum hydrocarbons such as naphtha is used as a raw material for carbon black. The majority of it is used as fuel. Therefore, converting this ethylene bottom oil into products with high added value is a challenge in the technical field. In order to solve this problem, attempts have been made to utilize the characteristics of ethylene bottom oil containing a large amount of aromatic compounds to produce binder pitch for carbon material production from ethylene bottom oil. However, petroleum-based pitch produced from petroleum-based heavy oil such as ethylene bottom oil has a lower amount of fixed carbon than coal tar pitch obtained from coal-based heavy oil, so the resulting carbon material has a lower density. There is a tendency to Therefore, coal tar pitch is currently mainly used as binder pitch and impregnated pitch.
ピッチの固定炭素量を高くするためには、一般的には、３００℃以上の高温、かつ１ＭＰａ以上の高圧下で熱改質を行い、重質化を進行させることが知られている。しかしながら、高温、かつ高圧での熱改質を行うためには、高価な製造設備が必要である。重質化のための他の方法として、ニトロ化反応を利用する方法が知られている。特開昭６０－２５５８８８号公報（特許文献１）では、二酸化窒素ガスを用いてエチレンボトム油のニトロ化を行っている。しかし、反応温度が１００℃以上と高く、重質化が進行し、得られるピッチの軟化点は２００℃以上である。したがって、得られるピッチは、黒鉛電極用のピッチとしては、好ましくない。特開平８－７３８６３公報（特許文献２）では、硝酸等の水溶液を用いて、石油系重質油のニトロ化を行っている。しかし、この方法では、ニトロ化後、多量の水分を除去する工程が必要となり、工業的に好ましくない。 In order to increase the amount of fixed carbon in pitch, it is generally known that thermal reforming is performed at a high temperature of 300° C. or higher and under a high pressure of 1 MPa or higher to promote heavier pitch. However, in order to carry out thermal reforming at high temperature and high pressure, expensive manufacturing equipment is required. As another method for increasing the weight, a method using a nitration reaction is known. In JP-A-60-255888 (Patent Document 1), nitration of ethylene bottom oil is performed using nitrogen dioxide gas. However, the reaction temperature is as high as 100°C or higher, the pitch becomes heavier, and the softening point of the resulting pitch is 200°C or higher. Therefore, the resulting pitch is not preferred as a pitch for graphite electrodes. In JP-A-8-73863 (Patent Document 2), heavy petroleum oil is nitrated using an aqueous solution of nitric acid or the like. However, this method requires a step of removing a large amount of water after nitration, which is not industrially preferable.
本発明は、簡便なニトロ化によって、高い固定炭素量の石油系ピッチを提供することを目的とする。なお、「石油系ピッチ」とは、石油由来の重質油から製造されたピッチをいう。 An object of the present invention is to provide a petroleum-based pitch with a high fixed carbon content through simple nitration. Note that "petroleum-based pitch" refers to pitch manufactured from heavy oil derived from petroleum.
本発明者らは、鋭意検討の結果、四酸化二窒素の存在下で石油系重質油のニトロ化を行った後、必要に応じて蒸留を行い、低沸点成分を留去することによって、固定炭素量が高い石油系ピッチが得られることを見出した。 As a result of extensive studies, the present inventors found that by nitrating petroleum heavy oil in the presence of dinitrogen tetroxide, and then distilling it as necessary to remove low-boiling components, It was discovered that a petroleum-based pitch with a high amount of fixed carbon can be obtained.
即ち、本発明は、以下の［１］～［８］に関する。
［１］
ニトロ化剤として四酸化二窒素を用い、石油系重質油をニトロ化する石油系ピッチの製造方法。
［２］
ニトロ化後、低沸点成分を留去する［１］に記載の石油系ピッチの製造方法。
［３］
前記石油系重質油がエチレンボトム油である［１］又は［２］に記載の石油系ピッチの製造方法。
［４］
ニトロ化を行う温度が１０℃～５０℃の範囲である［１］～［３］のいずれかに記載の石油系ピッチの製造方法。
［５］
得られた石油系ピッチの軟化点が７０℃～１３０℃、固定炭素量が４５質量％以上である［１］～［４］のいずれかに記載の石油系ピッチの製造方法。
［６］
石油系ピッチが、炭素材製造用である［１］～［５］のいずれかに記載の石油系ピッチの製造方法。
［７］
［１］～［６］のいずれかに記載の製造方法により得られた石油系ピッチをバインダーピッチとして用いる炭素材の製造方法。
［８］
前記炭素材が、黒鉛電極である［７］に記載の炭素材の製造方法。
That is, the present invention relates to the following [1] to [8].
[1]
A method for producing petroleum pitch that nitrates heavy petroleum oil using dinitrogen tetroxide as a nitrating agent.
[2]
The method for producing petroleum pitch according to [1], wherein after nitration, low-boiling components are distilled off.
[3]
The method for producing petroleum pitch according to [1] or [2], wherein the petroleum heavy oil is ethylene bottom oil.
[4]
The method for producing petroleum pitch according to any one of [1] to [3], wherein the nitration temperature is in the range of 10°C to 50°C.
[5]
The method for producing petroleum pitch according to any one of [1] to [4], wherein the obtained petroleum pitch has a softening point of 70° C. to 130° C. and a fixed carbon content of 45% by mass or more.
[6]
The method for producing petroleum-based pitch according to any one of [1] to [5], wherein the petroleum-based pitch is used for producing carbon materials.
[7]
A method for producing a carbon material using petroleum pitch obtained by the production method according to any one of [1] to [6] as a binder pitch.
[8]
The method for producing a carbon material according to [7], wherein the carbon material is a graphite electrode.
本発明によれば、四酸化二窒素を用いることで、従来のニトロ化よりも、低い温度で反応が進行し、その結果、固定炭素量が高く、所望の軟化点を有する炭素材製造用の石油系ピッチを得ることができる。加えて、ニトロ化反応において多量の水を使用する必要がないため、水分除去工程が不要であり、工業的に有利な製造プロセスを提供することができる。 According to the present invention, by using dinitrogen tetroxide, the reaction proceeds at a lower temperature than in conventional nitration, and as a result, a carbon material for producing a carbon material having a high amount of fixed carbon and a desired softening point Petroleum-based pitch can be obtained. In addition, since it is not necessary to use a large amount of water in the nitration reaction, a water removal step is not necessary, and an industrially advantageous production process can be provided.
以下、本発明の好ましい実施の形態について説明するが、本発明はこれらの形態のみに限定されるものではなく、その精神と実施の範囲内において様々な応用が可能であることを理解されたい。 Preferred embodiments of the present invention will be described below, but it should be understood that the present invention is not limited to these embodiments, and that various applications are possible within the spirit and scope of implementation.
＜黒鉛電極の製造工程＞
以下に黒鉛電極の一般的な製造工程の一例を述べる。
１．混練工程
ニードルコークスとバインダーピッチとを共に混合し、混練する工程
２．成形工程
混練物を押し出し等により成形して所定のサイズ及び形状の成形体を得る工程
３．焼成工程
成形体を焼成して焼成体を得る工程
４．含浸工程
焼成体に含浸ピッチを充填する工程
５．再焼成工程
含浸ピッチが充填された焼成体を再度焼成して再焼成体を得る工程
６．黒鉛化工程
再焼成体を黒鉛化する工程
７．加工工程
黒鉛化体を切削などにより所定の形状に成形し、黒鉛電極とする工程
<Manufacturing process of graphite electrode>
An example of a general manufacturing process for graphite electrodes will be described below.
1. Kneading process Step of mixing and kneading needle coke and binder pitch 2. Forming process Step of forming the kneaded material by extrusion or the like to obtain a molded product of a predetermined size and shape 3. Firing process Step of firing the molded body to obtain a fired body 4. Impregnation step Step of filling the fired body with impregnated pitch5. Re-firing process A process of re-firing the fired body filled with impregnated pitch to obtain a re-fired body6. Graphitization step 7. Graphitization step of graphitizing the refired body. Processing process The process of forming a graphitized body into a predetermined shape by cutting etc. to make a graphite electrode.
１．混練工程
粉砕し、分級し、所定の割合に粒度配合したニードルコークスとバインダーピッチとを共に混合及び混練する。バインダーピッチの配合量は、混練方法及び成形方法によって異なるが、一般に、ニードルコークス１００質量部に対して２０質量部～３０質量部程度である。
1. Kneading process Needle coke, which has been pulverized, classified, and has a particle size blended at a predetermined ratio, and binder pitch are mixed and kneaded together. The amount of binder pitch blended varies depending on the kneading method and molding method, but is generally about 20 parts by mass to 30 parts by mass per 100 parts by mass of needle coke.
混練物は酸化鉄等のパッフィング抑制剤を含んでもよい。 The kneaded material may also contain a puffing inhibitor such as iron oxide.
混合及び混練には市販の混合機又は混練機を用いることができる。具体的な例としてはミキサー、ニーダー等の混合機及び混練機を挙げることができる。混練温度は用いるバインダーピッチによって異なるが、一般的には１５０℃前後である。バインダーピッチの軟化点は１３０℃以下が好ましく、１１０℃以下が更に好ましい。１５０℃前後で混練する場合、バインダーピッチの軟化点が１３０℃より高いと十分に混練することが難しい。混練後、混練物はその後の成形に適する温度（１００℃～１３０℃）まで冷却される。 A commercially available mixer or kneader can be used for mixing and kneading. Specific examples include mixers and kneaders such as mixers and kneaders. The kneading temperature varies depending on the binder pitch used, but is generally around 150°C. The softening point of the binder pitch is preferably 130°C or lower, more preferably 110°C or lower. When kneading at around 150°C, it is difficult to sufficiently knead if the softening point of the binder pitch is higher than 130°C. After kneading, the kneaded material is cooled to a temperature (100° C. to 130° C.) suitable for subsequent molding.
２．成形工程
混練物を成形して所定のサイズ及び形状の成形体を得る。成形方法は目的とする炭素材によって押出成形、モールド成形等から適宜選択可能である。目的とする炭素材が黒鉛電極である場合は円柱形状への押出成形が一般的である。
2. Molding process The kneaded material is molded to obtain a molded body of a predetermined size and shape. The molding method can be appropriately selected from extrusion molding, mold molding, etc. depending on the intended carbon material. When the target carbon material is a graphite electrode, extrusion molding into a cylindrical shape is common.
３．焼成工程
前工程の成形体を昇温し、７００℃～１０００℃で焼成し、焼成体を得る。焼成工程は燃焼排ガス非酸化性雰囲気下で行うことが好ましい。成形体は昇温初期に軟化し、２００℃～５００℃でバインダーピッチの熱分解及び重縮合によって多量の分解ガスが発生し、気孔の生成と体積収縮が起こる。５００℃～６００℃でバインダーピッチは炭素化する。焼成工程は冷却も含め１ヶ月前後を要することが多い。
3. Firing Step The molded body from the previous step is heated and fired at 700°C to 1000°C to obtain a fired body. The firing step is preferably performed in a non-oxidizing combustion exhaust gas atmosphere. The molded body softens in the early stages of temperature rise, and a large amount of decomposed gas is generated due to thermal decomposition and polycondensation of the binder pitch at 200°C to 500°C, resulting in the formation of pores and volumetric contraction. The binder pitch carbonizes at 500°C to 600°C. The firing process, including cooling, often takes about a month.
４．含浸工程
焼成工程では、一般に、バインダーピッチの質量の３５％～４５％が揮発分として失われる。その際、焼成体には多量の気孔が発生する。この気孔に含浸ピッチを充填するのが含浸工程である。含浸は、例えばオートクレーブ中に焼成体を入れ、減圧下で脱気した後、熔融した含浸ピッチを注入し、約２００℃にて１ＭＰａ程度のガス圧で気孔に含浸ピッチを注入することで行われる。
4. Impregnation Step During the calcination step, typically 35% to 45% of the weight of the binder pitch is lost as volatiles. At this time, a large amount of pores are generated in the fired body. The impregnation step is to fill the pores with impregnated pitch. Impregnation is carried out by, for example, placing the fired body in an autoclave, degassing it under reduced pressure, and then injecting molten impregnated pitch into the pores at about 200°C and a gas pressure of about 1 MPa. .
５．再焼成工程
含浸ピッチが充填された焼成体を再度焼成して再焼成体を得る。再焼成も上記焼成工程と同様の条件で行うことができる。含浸工程と再焼成工程は必要に応じて繰り返し行ってもよい。
5. Re-firing step The fired body filled with impregnated pitch is fired again to obtain a re-fired body. Re-firing can also be performed under the same conditions as the above-mentioned firing step. The impregnation step and the re-firing step may be repeated as necessary.
６．黒鉛化工程
再焼成体を絶縁材料により囲まれた炉（アチソン炉、ＬＷＧ炉等）に仕込み、通電によるパッキングコークス又は再焼成体の抵抗発熱による熱処理を再焼成体に施す。黒鉛化の温度は２０００℃～３０００℃である。この温度は、再焼成体中の非晶質炭素を結晶質黒鉛に変換するために必要である。再焼成体を黒鉛に変換するために、数日間熱処理することが好ましい。
6. Graphitization process The refired body is placed in a furnace surrounded by an insulating material (Acheson furnace, LWG furnace, etc.), and the refired body is subjected to heat treatment using packing coke by energization or resistance heating of the refired body. The graphitization temperature is 2000°C to 3000°C. This temperature is necessary to convert the amorphous carbon in the refired body to crystalline graphite. Preferably, the refired body is heat treated for several days to convert it into graphite.
７．加工工程
黒鉛化体を切削等の機械加工により、所定の形状の黒鉛電極製品とする。黒鉛電極の密度（嵩密度）は、使用する電気炉設備及び電気炉の運転条件によって異なるが１．５ｇ／ｃｍ３～１．９ｇ／ｃｍ３であることが好ましい。
7. Processing process The graphitized body is machined such as cutting to produce a graphite electrode product in a predetermined shape. The density (bulk density) of the graphite electrode varies depending on the electric furnace equipment used and the operating conditions of the electric furnace, but is preferably 1.5 g/cm 3 to 1.9 g/cm 3 .
＜石油系ピッチの製造方法＞
一般的な石油系ピッチの製造方法は、エチレンボトム油などの石油系重質油を熱処理する工程と、熱処理された石油系重質油から低沸点物を蒸留により除去（留去）し、所望の固定炭素量と軟化点を持つピッチを製造する工程の２つの工程を含む。一実施形態の石油系ピッチの製造方法では、ニトロ化剤として四酸化二窒素を用い、石油系重質油をニトロ化するニトロ化工程を行う。ニトロ化は、熱処理された石油系重質油に対して行ってよく、熱処理されていない石油系重質油に対して行ってもよい。石油系重質油の熱処理を行わず、蒸留により低沸点物を留去して、固定炭素量を高めた石油系重質油をニトロ化工程に供してもよい。なお、本開示において「低沸点物」とは石油系重質油由来の低沸点成分を指し、「低沸点成分」とは低沸点物、溶媒等を含めたすべての低沸点成分を指す。
<Production method of petroleum pitch>
The general method for producing petroleum pitch involves a process of heat treating petroleum heavy oil such as ethylene bottom oil, and removing (distilling off) low boiling point substances from the heat treated petroleum heavy oil by distillation. It involves two steps: producing pitch with a fixed carbon content and softening point of . In one embodiment of the method for producing petroleum pitch, a nitration step is performed in which heavy petroleum oil is nitrated using dinitrogen tetroxide as a nitration agent. Nitration may be performed on petroleum-based heavy oil that has been heat-treated, or may be performed on petroleum-based heavy oil that has not been heat-treated. The petroleum heavy oil may be subjected to a nitration step without being subjected to heat treatment, but by distilling off low-boiling substances and increasing the amount of fixed carbon. In addition, in the present disclosure, "low boiling point substance" refers to a low boiling point component derived from petroleum heavy oil, and "low boiling point component" refers to all low boiling point components including low boiling point substances, solvents, etc.
一実施形態の石油系ピッチの製造方法は、ニトロ化後に蒸留工程を含むことが好ましく、以下の３工程：
１．熱処理工程 ：石油系重質油を熱処理する工程
２．ニトロ化工程：四酸化二窒素を用い、石油系重質油のニトロ化反応を行う工程
３．蒸留工程 ：低沸点成分を留去し、高沸点成分として石油系ピッチを得る工程
をこの順序で含むことがより好ましい。その他の工程が追加されてもよい。
The method for producing petroleum pitch of one embodiment preferably includes a distillation step after nitration, and the following three steps:
1. Heat treatment process: Process of heat treating petroleum heavy oil 2. Nitration step: Step 3 of performing a nitration reaction of petroleum heavy oil using dinitrogen tetroxide. Distillation step: It is more preferable to include a step of distilling off low-boiling components and obtaining petroleum pitch as a high-boiling component in this order. Other steps may be added.
本開示において固定炭素量とは、ＪＩＳ Ｋ２４２５：２００６「クレオソート油、加工タール及びタールピッチ試験方法」の「１１．固定炭素分定量方法」により測定される値であり、軟化点とは、ＪＩＳ Ｋ２４２５：２００６「クレオソート油、加工タール及びタールピッチ試験方法」の「８．タールピッチの軟化点測定方法（環球法）」により測定される値である。 In this disclosure, the amount of fixed carbon is the value measured by "11. Fixed carbon content determination method" of JIS K2425:2006 "Testing method for creosote oil, processed tar and tar pitch", and the softening point is the value measured by JIS K2425:2006 "Test method for creosote oil, processed tar and tar pitch". This is the value measured by "8. Method for measuring softening point of tar pitch (ring and ball method)" of K2425:2006 "Creosote oil, processed tar and tar pitch test method".
（石油系重質油、エチレンボトム油）
石油化学工業では一般に、ナフサ等を高温で熱分解し、得られた熱分解物を蒸留して、エチレン、プロピレン、及びその他のオレフィン類や、ベンゼン、トルエン、キシレン等の芳香族化合物、分解ケロシン、分解ガソリン等の各留分に分離し製品としている。これらの留分のうち、最も沸点が高い重質成分を「エチレンボトム油」といい、例えばカーボンブラック等の原料、及び燃料に使用される。
(Petroleum heavy oil, ethylene bottom oil)
In the petrochemical industry, naphtha and other materials are generally thermally decomposed at high temperatures, and the resulting thermal decomposition products are distilled to produce ethylene, propylene, and other olefins, aromatic compounds such as benzene, toluene, and xylene, and decomposed kerosene. , cracked gasoline and other fractions are separated into products. Among these fractions, the heavy component with the highest boiling point is called "ethylene bottom oil" and is used, for example, as a raw material for carbon black and other fuels.
ナフサ等の熱分解プラントは、エチレンプラントと称されることが多いため、前述の重質成分はエチレンボトム油と呼ばれている。ナフサの熱分解プラントは、ナフサクラッカーと呼ばれることもある。 Pyrolysis plants for naphtha and the like are often referred to as ethylene plants, so the aforementioned heavy components are referred to as ethylene bottom oil. A naphtha pyrolysis plant is sometimes called a naphtha cracker.
ナフサ含有原料の熱分解によって得られるエチレンボトム油の性状は、ナフサ含有原料の種類、熱分解条件、精製蒸留塔の運転条件等にもよるが、一般的に、５０％留出温度が２００℃～３５０℃、芳香族炭素含有割合が５０質量％以上、引火点が７０℃～９０℃、１００℃動粘度が１０ｍｍ２／ｓ未満である。ただし、エチレンボトム油は、炭化水素化合物の混合物であることから、上記の値は多少変動してもよい。 The properties of ethylene bottom oil obtained by thermal decomposition of naphtha-containing raw materials depend on the type of naphtha-containing raw material, thermal cracking conditions, operating conditions of the purification distillation column, etc., but generally the 50% distillation temperature is 200 ° C. -350°C, aromatic carbon content is 50% by mass or more, flash point is 70°C - 90°C, and kinematic viscosity at 100°C is less than 10 mm 2 /s. However, since ethylene bottom oil is a mixture of hydrocarbon compounds, the above values may vary somewhat.
石油系重質油は、エチレンボトム油、エチレンボトム油から任意の割合（例えば５～７０質量％）の軽質分を蒸留操作等によって除去したエチレンボトム油重質分若しくは除去されたエチレンボトム油軽質分、その他の石油系重質油又はそれらを混合したものでもよい。一実施形態では、石油系重質油はエチレンボトム油であることが好ましい。また、石油系重質油にコールタール等の重質油を添加してもよい。その他の石油系重質油としては特に限定されないが、例えば、流動接触分解油（ＦＣＣデカントオイル）、常圧蒸留残油、減圧蒸留残油等が挙げられる。ピッチ中の硫黄分及び窒素分は焼成時にパッフィングの原因になるため少ない方が好ましい。金属成分を多く含有するピッチを用いて黒鉛電極を製造した場合、これらの金属成分が黒鉛化時に蒸発し、黒鉛電極の密度が低下するため、製品の品質上好ましくない場合がある。これらの観点から、その他の石油系重質油としては、流動接触分解油（ＦＣＣデカントオイル）が好ましい。流動接触分解油（ＦＣＣデカントオイル）の性状は、原料、運転条件等にもよるが、一般的に、５０％留出温度が３００～４５０℃、引火点が６０℃～１６０℃、４０℃動粘度が４０ｍｍ２／ｓ未満である。ただし、流動接触分解油（ＦＣＣデカントオイル）は複雑な混合物であることから、上記の値は多少変動してもよい。 Petroleum-based heavy oil is ethylene bottom oil, ethylene bottom oil heavy fraction obtained by removing a desired proportion (for example, 5 to 70% by mass) of light components from ethylene bottom oil by distillation, or removed ethylene bottom oil light component. , other petroleum-based heavy oils, or a mixture thereof. In one embodiment, the petroleum heavy oil is preferably ethylene bottom oil. Further, heavy oil such as coal tar may be added to petroleum-based heavy oil. Examples of other petroleum-based heavy oils include, but are not particularly limited to, fluid catalytic cracking oil (FCC decant oil), atmospheric distillation residual oil, vacuum distillation residual oil, and the like. The sulfur content and nitrogen content in the pitch cause puffing during firing, so it is preferable that the content be as low as possible. When a graphite electrode is manufactured using pitch containing a large amount of metal components, these metal components evaporate during graphitization and the density of the graphite electrode decreases, which may be unfavorable in terms of product quality. From these viewpoints, fluid catalytic cracking oil (FCC decant oil) is preferred as the other petroleum heavy oil. The properties of fluid catalytic cracking oil (FCC decant oil) depend on the raw materials, operating conditions, etc., but generally the 50% distillation temperature is 300-450°C, the flash point is 60°C-160°C, and the temperature is 40°C. The viscosity is less than 40 mm 2 /s. However, since fluid catalytic cracking oil (FCC decant oil) is a complex mixture, the above values may vary somewhat.
（熱処理工程）
熱処理工程は、石油系重質油を熱処理する工程である。熱処理は、密閉容器にて非酸化性ガス雰囲気中で実施することが好ましい。非酸化性ガスとして、窒素ガス、アルゴン、水素ガス、メタンやエタン等の低級アルカン及びこれら非酸化性ガスの混合ガス等が挙げられるが、コスト及びハンドリングの容易さの観点から窒素ガスが好ましい。
(Heat treatment process)
The heat treatment process is a process of heat treating petroleum heavy oil. The heat treatment is preferably carried out in a non-oxidizing gas atmosphere in a closed container. Examples of the non-oxidizing gas include nitrogen gas, argon, hydrogen gas, lower alkanes such as methane and ethane, and mixed gases of these non-oxidizing gases, but nitrogen gas is preferred from the viewpoint of cost and ease of handling.
熱処理温度は、３６０℃～５００℃が好ましく、３９０℃～５００℃がより好ましく、４１０℃～４５０℃が更に好ましい。 The heat treatment temperature is preferably 360°C to 500°C, more preferably 390°C to 500°C, even more preferably 410°C to 450°C.
適切な熱処理時間は、熱処理温度によって異なる。熱処理温度が３６０℃～３９０℃の場合は、所定の熱処理温度に到達した時（以下同様）から、８時間～４８時間が好ましく、１６時間～４８時間がより好ましい。熱処理温度が３９０℃超～４３０℃の場合は、０．５時間～２４時間が好ましく、１時間～１６時間がより好ましい。熱処理温度が４３０℃超～５００℃の場合は、１時間～１６時間が好ましく、０．５時間～８時間がより好ましい。熱処理時間を上記範囲とすることで、適切な固定炭素量のピッチを得ることができる。 Appropriate heat treatment time varies depending on the heat treatment temperature. When the heat treatment temperature is 360° C. to 390° C., it is preferably 8 hours to 48 hours, more preferably 16 hours to 48 hours, from the time the predetermined heat treatment temperature is reached (the same applies hereinafter). When the heat treatment temperature is higher than 390°C to 430°C, it is preferably 0.5 to 24 hours, more preferably 1 to 16 hours. When the heat treatment temperature is higher than 430°C to 500°C, it is preferably 1 hour to 16 hours, more preferably 0.5 hour to 8 hours. By setting the heat treatment time within the above range, a pitch with an appropriate amount of fixed carbon can be obtained.
熱処理開始時の圧力（初期圧力）は、０ＭＰａＧであることが好ましいが、特に制限はない。密閉容器内の圧力は、熱処理中に起こる熱分解により発生した水素ガス及びメタンやエタン等の低級アルカン等により上昇する。密閉容器内の圧力に制限はないが、常圧下ではキノリン不溶分（ＱＩ）及びトルエン不溶分（ＴＩ）が生成しやすく、最終的なピッチ収率が低下するため加圧条件が好ましい。なお、ＱＩは、ＪＩＳ Ｋ ２４２５：２００６「クレオソート油、加工タール及びタールピッチ試験方法」の「１５．タールピッチのキノリン不溶分定量方法」により測定される値である。ＴＩは、ＪＩＳ Ｋ ２４２５：２００６「クレオソート油、加工タール及びタールピッチ試験方法」の「１４．２加工タール及びタールピッチのトルエン不溶分定量方法」に記載の濾過法に準拠して測定される値である。 The pressure at the start of the heat treatment (initial pressure) is preferably 0 MPaG, but is not particularly limited. The pressure inside the closed container increases due to hydrogen gas and lower alkanes such as methane and ethane generated by thermal decomposition that occurs during heat treatment. Although there is no restriction on the pressure inside the closed container, pressurized conditions are preferable because quinoline insoluble matter (QI) and toluene insoluble matter (TI) are likely to be produced under normal pressure, which lowers the final pitch yield. Note that QI is a value measured according to "15. Method for determining quinoline insoluble content in tar pitch" of JIS K 2425:2006 "Testing methods for creosote oil, processed tar, and tar pitch." TI is measured in accordance with the filtration method described in "14.2 Method for determining toluene insoluble content of processed tar and tar pitch" in JIS K 2425: 2006 "Testing methods for creosote oil, processed tar and tar pitch". It is a value.
（ニトロ化工程）
ニトロ化工程では、ニトロ化剤として四酸化二窒素（Ｎ２Ｏ４）を用い、石油系重質油のニトロ化を行う。ニトロ化反応により、得られるピッチの固定炭素量を高くすることができる。四酸化二窒素は、融点が－１１．２℃、常圧での沸点が２１．１℃であることから、条件を選べば液体で取り扱える点で好ましい。
(Nitration process)
In the nitration step, heavy petroleum oil is nitrated using dinitrogen tetroxide (N 2 O 4 ) as a nitration agent. The nitration reaction can increase the amount of fixed carbon in the pitch obtained. Dinitrogen tetroxide has a melting point of -11.2°C and a boiling point of 21.1°C at normal pressure, so it is preferable because it can be handled as a liquid under selected conditions.
ニトロ化は、石油系重質油とニトロ化剤である四酸化二窒素とを反応させることにより行う。四酸化二窒素ガスを石油系重質油に吹き込んでもよいが、液体の四酸化二窒素を溶媒に溶かして石油系重質油と反応させることが、反応制御が容易なため好ましい。石油系重質油を溶媒に溶かした状態でニトロ化を行ってもよい。過度なニトロ化によって、得られるピッチの軟化点が上昇しすぎることを防ぐため、四酸化二窒素を溶媒に溶かし、得られた溶液を石油系重質油に滴下することが好ましい。 Nitration is performed by reacting petroleum heavy oil with dinitrogen tetroxide, which is a nitration agent. Although dinitrogen tetroxide gas may be blown into the petroleum heavy oil, it is preferable to dissolve liquid dinitrogen tetroxide in a solvent and react with the petroleum heavy oil because the reaction can be easily controlled. Nitration may be performed with petroleum heavy oil dissolved in a solvent. In order to prevent the softening point of the resulting pitch from rising too much due to excessive nitration, it is preferable to dissolve dinitrogen tetroxide in a solvent and drop the resulting solution into petroleum heavy oil.
溶媒は、石油系重質油を溶解し、溶媒自体のニトロ化が進行しないものが好ましい。加えて、ニトロ化反応後に、石油系重質油から容易に留去できる低沸点のものが好ましい。具体的には、クロロホルム及びジクロロメタン等のハロゲン系溶媒が好ましい。 The solvent is preferably one that dissolves petroleum heavy oil and does not cause nitration of the solvent itself. In addition, it is preferable to use a substance with a low boiling point that can be easily distilled off from heavy petroleum oil after the nitration reaction. Specifically, halogen solvents such as chloroform and dichloromethane are preferred.
ニトロ化を行う温度は、１０～５０℃が好ましく、より好ましくは２０～５０℃であり、さらに好ましくは２０～３０℃である。５０℃以下であれば、ニトロ化が過度に進行することによって、得られるピッチの軟化点が上昇することを抑制することができる。１０℃以上であれば、反応速度を維持できる。 The temperature at which the nitration is carried out is preferably 10 to 50°C, more preferably 20 to 50°C, even more preferably 20 to 30°C. If the temperature is 50° C. or lower, it is possible to prevent the softening point of the pitch obtained from increasing due to excessive progress of nitration. If the temperature is 10°C or higher, the reaction rate can be maintained.
ニトロ化を行う時間は、１０～１２０分間が好ましく、より好ましくは１０～６０分間であり、さらに好ましくは２０～４０分間である。ニトロ化時間が長いと、ニトロ化が過度に進行し、得られるピッチの軟化点が上昇する。 The time for nitration is preferably 10 to 120 minutes, more preferably 10 to 60 minutes, and even more preferably 20 to 40 minutes. If the nitration time is long, nitration will proceed excessively and the softening point of the resulting pitch will increase.
ニトロ化反応時の圧力は、常圧であってよく、四酸化二窒素の揮散を防ぐため、常圧～１．０ＭＰaが好ましく、常圧～０．５ＭＰａがより好ましく、常圧～０．３ＭＰａがさらに好ましい。 The pressure during the nitration reaction may be normal pressure, and in order to prevent dinitrogen tetroxide from volatilizing, normal pressure to 1.0 MPa is preferable, normal pressure to 0.5 MPa is more preferable, normal pressure to 0.3 MPa. is even more preferable.
四酸化二窒素は、基質の石油系重質油１００質量部に対して、１０～７０質量部が好ましく、より好ましくは１０～６０質量部であり、さらに好ましくは１５～５０質量部である。四酸化二窒素の量が多いと、ニトロ化が過度に進行し、得られるピッチの軟化点が上昇する。 The amount of dinitrogen tetroxide is preferably 10 to 70 parts by mass, more preferably 10 to 60 parts by mass, and even more preferably 15 to 50 parts by mass, based on 100 parts by mass of petroleum heavy oil as the substrate. If the amount of dinitrogen tetroxide is large, nitration will proceed excessively and the softening point of the resulting pitch will increase.
ニトロ化を行う反応容器は、耐食性の素材で構成されていることが好ましい。具体的には、ガラス製容器やハステロイ（商標）製容器などが好ましい。 The reaction vessel for nitration is preferably made of a corrosion-resistant material. Specifically, glass containers, Hastelloy (trademark) containers, and the like are preferred.
（蒸留工程）
蒸留工程は、ニトロ化工程で得られたニトロ化石油系重質油から、未反応の四酸化二窒素、溶媒、及び石油系重質油中の低沸点物などの低沸点成分を蒸留により除去（留去）し、高沸点成分として、所望の軟化点と固定炭素量を有する石油系ピッチを製造する工程である。
(distillation process)
In the distillation process, low-boiling components such as unreacted dinitrogen tetroxide, solvent, and low-boiling substances in petroleum-based heavy oil are removed by distillation from the nitrated petroleum-based heavy oil obtained in the nitration process. (distillation) to produce petroleum pitch having a desired softening point and fixed carbon content as a high boiling point component.
蒸留の方法は、常圧蒸留、減圧蒸留（真空蒸留）、常圧蒸留と減圧蒸留とを組み合わせたもののいずれでもよく、適宜選択される。 The distillation method may be any one of normal pressure distillation, reduced pressure distillation (vacuum distillation), and a combination of normal pressure distillation and reduced pressure distillation, and is appropriately selected.
蒸留釜の内部温度は、３５０℃を超えないことが好ましい。３５０℃を超えると、ピッチの重合などの反応が起こり、得られるピッチの軟化点が大きく上昇してしまうため、好ましくない。蒸留時の温度は、５０～３５０℃が好ましく、より好ましくは５０～３００℃、さらに好ましくは、５０～２５０℃である。 The internal temperature of the still still preferably does not exceed 350°C. If the temperature exceeds 350°C, reactions such as polymerization of pitch will occur, and the softening point of the resulting pitch will increase significantly, which is not preferable. The temperature during distillation is preferably 50 to 350°C, more preferably 50 to 300°C, even more preferably 50 to 250°C.
蒸留は、蒸留温度を上げないために、減圧下で行うことが好ましい。減圧下で蒸留を行う場合、軟化点が７０℃～１３０℃のピッチを得るために、蒸留時の圧力は、１００～１００００Ｐａが好ましく、より好ましくは５００～４０００Ｐａ、さらに好ましくは、８００～３０００Ｐａである。 Distillation is preferably carried out under reduced pressure so as not to increase the distillation temperature. When distilling under reduced pressure, in order to obtain pitch with a softening point of 70°C to 130°C, the pressure during distillation is preferably 100 to 10,000 Pa, more preferably 500 to 4,000 Pa, and even more preferably 800 to 3,000 Pa. be.
ピッチの軟化点は、石油系重質油中の低沸点物の除去量により制御することができる。一般的に、低沸点物の除去量が多いと高軟化点になり、少ないと低軟化点になる。 The softening point of the pitch can be controlled by the amount of low boiling point substances removed from the petroleum heavy oil. Generally, if the amount of low boiling point substances removed is large, the softening point will be high, and if it is small, the softening point will be low.
＜石油系ピッチ＞
石油系ピッチは、炭素材の製造に用いることができ、例えば、炭素材製造用の含浸ピッチ及びバインダーピッチとして使用可能である。特に、黒鉛電極製造で使用されるバインダーピッチとして用いることができる。
<Petroleum pitch>
Petroleum-based pitch can be used in the production of carbon materials, and can be used, for example, as impregnated pitch and binder pitch for the production of carbon materials. In particular, it can be used as a binder pitch used in graphite electrode manufacture.
石油系ピッチの軟化点は１３０℃以下が好ましく、７０℃～１３０°がより好ましい。バインダーピッチとして用いる場合の軟化点は、７０℃～１２０℃が好ましく、７０℃～１１０℃が更に好ましい。 The softening point of the petroleum pitch is preferably 130°C or lower, more preferably 70°C to 130°. The softening point when used as a binder pitch is preferably 70°C to 120°C, more preferably 70°C to 110°C.
固定炭素量が高いほど得られる黒鉛電極の密度が高くなる傾向にあるため、一実施形態の石油系ピッチの固定炭素量は、４５質量％以上であることが好ましく、５０質量％以上であることがより好ましい。固定炭素量の上限は特に限定されないが、例えば７５質量％又は８５質量％である。 Since the higher the amount of fixed carbon, the higher the density of the graphite electrode obtained, the amount of fixed carbon in the petroleum pitch of one embodiment is preferably 45% by mass or more, and preferably 50% by mass or more. is more preferable. The upper limit of the amount of fixed carbon is not particularly limited, but is, for example, 75% by mass or 85% by mass.
Ｎ（窒素原子）含有量は、多いほど炭化反応に寄与し、ピッチの固定炭素量を高くする。一方でＮ含有量が多すぎるとピッチの粘度も増加させてしまい、軟化点が高くなる。一実施形態の石油系ピッチのＮ含有量は、１．０～１０質量％が好ましく、より好ましくは、１．０～７．０質量％、さらに好ましくは、１．５～５．０質量％である。Ｎ含有量の測定は、実施例の項に記載の方法による。 The higher the N (nitrogen atom) content, the more it contributes to the carbonization reaction and increases the amount of fixed carbon in the pitch. On the other hand, if the N content is too large, the viscosity of the pitch will also increase and the softening point will increase. The N content of the petroleum pitch of one embodiment is preferably 1.0 to 10% by mass, more preferably 1.0 to 7.0% by mass, and even more preferably 1.5 to 5.0% by mass. It is. The N content was measured by the method described in the Examples section.
本発明をさらに以下の実施例及び比較例を参照して説明するが、これらの実施例は本発明の概要を示すもので、本発明はこれらの実施例に限定されるものではない。 The present invention will be further explained with reference to the following Examples and Comparative Examples; however, these Examples provide an overview of the present invention, and the present invention is not limited to these Examples.
＜軟化点（ＳＰ）の測定方法＞
ＪＩＳ Ｋ ２４２５：２００６「クレオソート油、加工タール及びタールピッチ試験方法」の「８．タールピッチの軟化点測定方法（環球法）」に準拠して測定した。
<Method for measuring softening point (SP)>
Measurement was performed in accordance with JIS K 2425:2006 "Creosote oil, processed tar, and tar pitch test method", "8. Method for measuring softening point of tar pitch (ring and ball method)".
＜固定炭素（ＦＣ）量の測定方法＞
ＪＩＳ Ｋ ２４２５：２００６「クレオソート油、加工タール及びタールピッチ試験方法」の「１１．固定炭素分定量方法」に準拠して測定した。
<Measurement method of fixed carbon (FC) amount>
Measurement was performed in accordance with "11. Fixed carbon content determination method" of JIS K 2425:2006 "Creosote oil, processed tar and tar pitch test method".
＜Ｎ含有量の測定方法＞
ＣＨＮ元素分析法により、試料中のＮ含有量を測定した。
<Method for measuring N content>
The N content in the sample was measured by CHN elemental analysis.
＜赤外吸収分光測定方法＞
ＫＢｒ法にて、赤外吸収分光法分析を行い、１５５０ｃｍ－１の吸収から、ニトロ基の存在を確かめた。
<Infrared absorption spectroscopy measurement method>
Infrared absorption spectroscopy analysis was performed using the KBr method, and the presence of a nitro group was confirmed from the absorption at 1550 cm -1 .
（実施例１）
エチレンボトム油２５６ｇをガラス製容器に導入し、２８０℃で、常圧蒸留を行うことにより、低沸点成分を留去し、高沸点成分１９３ｇを、低沸点成分を留去したエチレンボトム油として得た（収率７５％）。
(Example 1)
256 g of ethylene bottom oil was introduced into a glass container and subjected to atmospheric distillation at 280°C to distill off low boiling point components and obtain 193 g of high boiling point components as ethylene bottom oil from which low boiling point components had been distilled off. (yield 75%).
低沸点成分を留去したエチレンボトム油２５ｇをガラス製容器中でジクロロメタン５０ｍＬに溶解した。得られたエチレンボトム油溶液を３０℃で撹拌しながら、四酸化二窒素４ｇを２０ｍＬのジクロロメタンに溶解させた溶液を、３０分かけて滴下した後、常圧にて３０分間撹拌し、合計で６０分間ニトロ化を行った。ニトロ化後、２６００Ｐａ、９０℃の条件で減圧蒸留を行い、溶媒、未反応四酸化二窒素、及びその他の低沸点成分を留去し、ピッチ１を２８ｇ得た（収率９７％）。得られたピッチ１を用いて、軟化点、固定炭素量、及びＮ含有量を測定し、赤外吸収分光法分析にてニトロ基が導入されていることを確かめた。 25 g of ethylene bottom oil from which low-boiling components had been distilled off was dissolved in 50 mL of dichloromethane in a glass container. While stirring the obtained ethylene bottom oil solution at 30°C, a solution of 4 g of dinitrogen tetroxide dissolved in 20 mL of dichloromethane was added dropwise over 30 minutes, and the mixture was stirred at normal pressure for 30 minutes. Nitration was carried out for 60 minutes. After nitration, vacuum distillation was performed under conditions of 2600 Pa and 90° C. to remove the solvent, unreacted dinitrogen tetroxide, and other low-boiling components to obtain 28 g of pitch 1 (yield 97%). Using the obtained pitch 1, the softening point, amount of fixed carbon, and N content were measured, and it was confirmed by infrared absorption spectroscopy that nitro groups were introduced.
（実施例２）
四酸化二窒素の量を８ｇに変更した以外は、実施例１と同様の方法で、ピッチ２を３０ｇ得た。
(Example 2)
30 g of pitch 2 was obtained in the same manner as in Example 1 except that the amount of dinitrogen tetroxide was changed to 8 g.
（実施例３）
四酸化二窒素の量を１１ｇに変更した以外は、実施例１と同様の方法で、ピッチ３を３４ｇ得た。
(Example 3)
34 g of pitch 3 was obtained in the same manner as in Example 1 except that the amount of dinitrogen tetroxide was changed to 11 g.
（比較例１）
エチレンボトム油２５６ｇをガラス製容器に導入し、２８０℃で、常圧蒸留を行うことにより、低沸点成分を留去したエチレンボトム油１（ＥＢＯ－１）を１９３ｇ得た（収率７５％）。
(Comparative example 1)
256 g of ethylene bottom oil was introduced into a glass container and subjected to atmospheric distillation at 280°C to obtain 193 g of ethylene bottom oil 1 (EBO-1) from which low boiling point components were distilled off (yield 75%). .
（比較例２）
エチレンボトム油２５６ｇをガラス製容器に導入し、３２０℃で、常圧蒸留を行うことにより、低沸点成分を留去したエチレンボトム油２（ＥＢＯ－２）を１８０ｇ得た（収率５６％）。
(Comparative example 2)
256 g of ethylene bottom oil was introduced into a glass container and subjected to atmospheric distillation at 320°C to obtain 180 g of ethylene bottom oil 2 (EBO-2) from which low-boiling components were distilled off (yield 56%). .
本発明によれば、従来の硝酸等を使ったニトロ化反応で必要だった多量の水分の除去工程を必要とせず、高温かつ高圧下での熱処理を行わずに、低軟化点、及び高固定炭素量を有する炭素材製造用のピッチを得ることができる。 According to the present invention, it is possible to achieve a low softening point and high fixation without requiring a large amount of water removal process required in the conventional nitration reaction using nitric acid, etc., and without heat treatment at high temperature and high pressure. A pitch for producing a carbon material having a carbon content can be obtained.
Claims (8)
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