A method for improving the electrical properties of needle coke

Abstract

The application provides a method for improving the electric performance of needle coke, which comprises adding condensed aromatic hydrocarbon compounds during the coking reaction of coking raw materials, continuously performing the coking reaction, and obtaining needle coke products. The method is simple to operate, and the needle coke obtained by the method has excellent electric performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of needle coke, in particular to a method for improving the electrical properties of needle coke. BACKGROUND

[0002] Needle coke is a porous carbonaceous solid with silvery gray appearance and metallic luster, and the surface thereof has a fine and long needle-like or fibrous texture. The interior thereof has a layered structure similar to that of graphite crystals. Needle coke is a carbonization product of petroleum pitch or coal pitch, and is an important raw material in the carbon industry. Needle coke has a low thermal expansion coefficient, high electrical conductivity, high mechanical strength, corrosion resistance, and large true density. Needle coke is mainly used to produce high-power and super-high-power graphite electrodes, and can reduce power consumption and electrode loss. Activated needle coke can be used as an anode catalytic material for capacitors or methanol fuel cells, and modified needle coke can be used as a negative electrode material for lithium ion batteries. Needle coke has special uses and important significance in the national defense industry and civil industry, and has significant economic and social benefits.

[0003] Petroleum-based needle coke is produced by using thermal cracking residual oil, catalytic cracking clarified oil, lubricating oil refined extract oil, steam cracking tar, catalytic oil slurry, etc. as raw materials. From the current industrialized devices, relatively more devices are used to produce needle coke from oil-based raw materials. From the generation mechanism of needle coke, the raw material must have a high content of aromatic hydrocarbons (thick ring macromolecular aromatic hydrocarbons are not included), a low content of impurities, a low content of asphaltene, a low content of ash, and can produce large mesophase spherules during the conversion process. The sulfur content of needle coke product is strictly required. The escape of sulfur during the graphitization process of needle coke will cause crystal expansion, which will seriously damage the electrode strength of graphite. Therefore, on the one hand, the sulfur in the catalytic cracking oil slurry needs to be removed, and on the other hand, saturation of aromatic hydrocarbons needs to be avoided as much as possible.

[0004] In the prior art, the raw material for producing needle coke is usually pretreated, and then delayed coking is performed to produce needle coke, so as to improve the quality of needle coke product. For example, CN1382761A discloses a pretreatment method for producing needle coke raw material, which uses lubricating oil extract to extract the catalyst powder in the catalytic cracking clarified oil, and then performs delayed coking to produce needle coke. CN1872963A first performs vacuum distillation and hydrogenation treatment on the raw material for producing needle coke, so that the ash content and sulfur content of the needle coke production raw material are greatly reduced, and then performs delayed coking to produce needle coke. The above methods can improve the quality of needle coke product, but cannot improve the uniformity and strength of needle coke quality.

[0005] CN1418930A discloses a method for preparing needle coke by first heat-treating coal-based needle coke raw materials and petroleum-based needle coke raw materials under conditions lower than coking temperature to improve their compatibility, and then co-coking. Due to the heat treatment, the mutual compatibility can be improved, and needle coke with high coking yield and good optical structure can be prepared. However, due to the high heat treatment temperature, on the one hand, low molecular substances in the coal-based needle coke raw materials will undergo polycondensation to form β resin, and the generated β resin and the original β resin will further undergo polycondensation to form quinoline insoluble at high temperature, on the other hand, the oil-based needle coke raw materials will also undergo polycondensation to form quinoline insoluble during high-temperature heat treatment, and the combined effects of the two aspects will greatly increase the content of quinoline insoluble in the needle coke raw materials, resulting in a large expansion coefficient of the prepared needle coke, which seriously affects the performance of the needle coke when used as an electrode.

[0006] US5128026 improves the product quality uniformity of needle coke produced by delayed coking by oxidizing pretreatment of the needle coke raw materials, which can improve the uniformity of the thermal expansion coefficient of the needle coke, but does not improve the strength of the needle coke, and also causes the oxygen content of the raw materials and products to increase, affecting the quality of the needle coke. US5286371 uses a combination of residual oil hydroprocessing, solvent deasphalting, and catalytic raw material hydroprocessing, which can meet the requirements of sulfur content, thermal expansion coefficient, etc. of needle coke produced by delayed coking, but cannot improve the quality uniformity and strength of the needle coke.

[0007] CN110330337A discloses an ultrahigh-power graphite electrode and a preparation method thereof, which improves the electrical conductivity of the graphite electrode by increasing the content of needle coke in the graphite electrode. With the increase of the amount of needle coke, the resistivity can be greatly reduced, the electrical conductivity of the graphite electrode can be improved, the power loss can be reduced, and the electrical conductivity efficiency can be improved. CN110396419A discloses coal needle coke, a preparation method thereof, a lithium ion battery negative electrode material, and a lithium ion battery. The method can prepare coal needle coke with improved thermal expansion coefficient, and further obtain negative electrode material with improved electrical performance. Although the electrical performance of the needle coke prepared by the method is improved, it is still not ideal.

[0008] Better electrical conductivity is one of the characteristics of needle coke and is also the basis for its use as a high-power electrode. Needle coke has better electrical conductivity than ordinary coke, and the better the electrical conductivity, the higher the application value. Therefore, improving the electrical performance of needle coke is one of the goals of producing needle coke products. SUMMARY

[0009] The present application provides a method for improving the electrical performance of needle coke.

[0010] The method for improving the performance of needle coke according to the present application comprises adding a polycyclic aromatic hydrocarbon compound to a coking raw material during a coking reaction, and continuously performing the coking reaction to produce a needle coke product.

[0011] According to the present application, the coking raw material is preferably one or more of catalytic cracking slurry oil, catalytic cracking clarified oil, ethylene tar obtained by steam cracking of naphtha to produce ethylene, ethylene tar obtained by steam cracking of gas oil to produce ethylene, thermal cracking tar, coal tar produced by coal coking, and coal tar produced by coal gasification, and more preferably catalytic cracking slurry oil.

[0012] According to the present application, the polycyclic aromatic hydrocarbon compound is added in an amount of 0.01% to 0.1% of the total mass of the coking raw material, and preferably 0.03% to 0.08%.

[0013] According to the present application, the polycyclic aromatic hydrocarbon compound is preferably a C8 to C 28 polycyclic aromatic hydrocarbon compound, and more preferably a C 13 to C 18 polycyclic aromatic hydrocarbon compound. The polycyclic aromatic hydrocarbon compound is further preferably a C8 to C 28 polycyclic aromatic hydrocarbon compound that does not contain a heteroatom and does not contain a branched alkane. The heteroatom can include S, N, and O.

[0014] According to the present application, the polycyclic aromatic hydrocarbon compound can be an 18 polycyclic aromatic hydrocarbon compound and / or a 13 polycyclic aromatic hydrocarbon compound.

[0015] According to the present application, the 18 polycyclic aromatic hydrocarbon compound has the following structure:

[0016]

[0017] and the IUPAC name thereof is:

[0018] Octadecacyclo

[0019] [16.12.20.5 6,10 .1 38,42 .0 2,23 .0 5,22 .0 8,21 .0 9,14 .0 15,20 .0 19,24 .0 25,30 .0 26,50 .0 27,47 .0 28 ,40 .0 29,33 .0 34,39 .0 41,46 .0 7,53 ]

[0020] hexapentaconta-

[0021] 1(31),2,4,6(56),7,9(14),10,12,15(20),16,18,21,23,25(30),26(50),27(47),28,32,34,36,38(51),39,41(46),42,44,48,52,54-octacosaene.

[0022] According to the present application, the structure of the 13 fused ring aromatic compound is:

[0023]

[0024] The IUPAC name of which is:

[0025] Tridecacyclo

[0026] [27.11.1.1 16,20 .0 2,7 .0 3,28 .0 4,25 .0 5,18 .0 6,11 .0 8,39 .0 12,17 .0 19,24 .0 33,41 .0 35,40 ]

[0027] dotetraconta-

[0028] 1(41),2,4,6(11),7,9,12(17),13,15,18,20(42),21,23,25,27,29,31,33,35,37,39-

[0029] Henicosaene.

[0030] According to the present application, the coking raw material can be subjected to a coking reaction in a coking tower.

[0031] According to the present application, the fused ring aromatic compound is preferably added after 1 to 3 hours of the coking reaction.

[0032] According to the present application, the oil gas generated during the coking reaction can be introduced into a fractionating tower, and a gas, a light oil, a middle distillate oil and a heavy distillate oil are fractionated in the fractionating tower, wherein the heavy distillate oil can be recycled back to the coking tower, and the recycle ratio can be 0.3 to 0.8, and the distillation range of the heavy distillate oil is preferably 400 to 520°C.

[0033] According to the present application, preferably, the coking feedstock is continuously fed into the coking tower, and the space velocity of the coking feedstock continuously fed into the coking tower is preferably 0.5-5h -1 , more preferably 1-3.5h -1 .

[0034] According to the present application, the temperature in the coking tower is preferably 350-550℃, more preferably 460-500℃.

[0035] According to the present application, the pressure in the coking tower is preferably 0.3-0.5MPa, more preferably 0.35-0.45MPa.

[0036] According to the present application, the coking period of the coking feedstock in the coking tower is preferably 10-40h, more preferably 30-40h. The coking period includes the reaction time before and after the addition of the condensed aromatic hydrocarbon compound.

[0037] The method of the present application is simple to operate, and the needle coke prepared by the method of the present application has excellent electrical properties. DETAILED DESCRIPTION

[0038] The technical solutions of the present application will be further understood by the following examples and comparative examples. The condensed aromatic hydrocarbon compound used herein includes octadecan condensed aromatic hydrocarbon compound (CAS No. 1419640-34-8) and tridecan condensed aromatic hydrocarbon compound (CAS No. 82599-56-2), both of which are from Shanghai Bide Pharmaceutical Technology Co., Ltd. The coking feedstock used is Jinzhou Petrochemical catalytic cracking slurry, and its properties are shown in Table 1. The electrical conductivity of the needle coke is tested according to the standard method of GB / T 1552-1995, and the electrical conductivity meter used is FT-8100A.

[0039] Table 1 Properties of the coking feedstock

[0040] Item Property Density (20°C) / (g / cm 3 )]]> 1.04 Ash / w% <0.002 Element / w% S 0.24 N 0.17 Four component / w% Saturated hydrocarbon 13.2 Aromatic hydrocarbon 77.1 Gum 6.7 Asphaltene 3.0 Distillation / ℃ 10％ 377 90％ 518

[0041] Comparative Example 1

[0042] The needle coke production test is carried out on a delayed coking pilot plant with a processing capacity of 10kg / h, and the catalytic cracking slurry is continuously fed from the lower part of the coking tower for coking reaction, with a volume space velocity of 1.0h -1 , and the oil gas generated by the coking reaction enters the fractionating tower to obtain gas, light oil, middle distillate oil and heavy distillate oil, the distillation range of the heavy distillate oil is 400-520℃, and the heavy distillate oil is recycled back to the lower part of the coking tower with a recycle ratio of 0.5, the temperature in the coking tower is 480℃, the pressure is 0.4MPa, and the coking period is 32 hours, and the needle petroleum coke product is obtained in the coking tower, and its electrical conductivity is tested to be 3.86S / m.

[0043] Example 1

[0044] A test for producing needle coke was carried out in a delayed coking pilot plant with the same processing capacity of 10 kg / h as in Comparative Example 1, and catalytic cracking slurry oil was continuously fed from the lower part of the coking tower for coking reaction at a volume space velocity of 1.0 h -1 The oil gas generated in the coking reaction was introduced into a fractionating tower, and gas, light oil, middle distillate oil and heavy distillate oil were obtained by fractionation, the distillation range of the heavy distillate oil being 400-520°C, wherein the heavy distillate oil was recycled to the lower part of the coking tower at a recycle ratio of 0.5, the temperature in the coking tower was 480°C, and the pressure was 0.4 MPa; after 2 hours of coking reaction, octadecahydroannulene was added to the middle part of the coking tower, the addition amount being 0.03% of the total mass of the catalytic cracking slurry oil fed during the coking cycle, and the coking reaction was continuously carried out; the coking cycle was 32 hours, and needle petroleum coke was obtained in the coking tower, the conductivity of which was tested to be 4.36 S / m. The coking cycle included the reaction time before the addition of octadecahydroannulene and the reaction time after the addition of octadecahydroannulene.

[0045] Example 2

[0046] The coking reaction was carried out using the same device, raw materials and method as in Example 1, except that the addition amount of octadecahydroannulene added after 2 hours of coking reaction was 0.05% of the total mass of the catalytic cracking slurry oil fed during the coking cycle. The needle petroleum coke obtained was tested for conductivity, and the conductivity was measured to be 4.64 S / m.

[0047] Example 3

[0048] The coking reaction was carried out using the same device, raw materials and method as in Example 1, except that the addition amount of octadecahydroannulene added after 2 hours of coking reaction was 0.08% of the total mass of the catalytic cracking slurry oil fed during the coking cycle. The needle petroleum coke obtained was tested for conductivity, and the conductivity was measured to be 5.18 S / m.

[0049] Example 4

[0050] The coking reaction was carried out using the same device, raw materials and method as in Example 1, except that tridecahydroannulene was added after 2 hours of coking reaction, the addition amount being 0.05% of the total mass of the catalytic cracking slurry oil fed during the coking cycle. The needle petroleum coke obtained was tested for conductivity, and the conductivity was measured to be 4.15 S / m.

[0051] Although the present application has been disclosed by the above-mentioned embodiments, these embodiments are not intended to limit the present application, and any person skilled in the art to which the present application pertains can make various changes and modifications without departing from the spirit and scope of the present application, and these changes and modifications are intended to fall within the scope of the present application.

Claims

1. A method of improving the electrical properties of needle coke comprising: The polycyclic aromatic hydrocarbon compound is added to coking raw material to carry out coking reaction, and needle coke product is prepared; the coking raw material is catalytic cracking slurry oil; The polycyclic aromatic hydrocarbon compound is added to coking raw material to carry out coking reaction, and needle coke product is prepared; the coking raw material is catalytic cracking slurry oil; The polycyclic aromatic hydrocarbon compound is added to coking raw material to carry out coking reaction, and needle coke product is prepared; the coking raw material is catalytic cracking slurry oil; The polycyclic aromatic hydrocarbon compound is added to coking raw material to carry out coking reaction, and needle coke product is prepared; the coking raw material is catalytic cracking slurry oil; 2. The method of claim 1, wherein, The polycyclic aromatic hydrocarbon compound is added to coking raw material to carry out coking reaction, and needle coke product is prepared; the coking raw material is catalytic cracking slurry oil; 3. The method of claim 1, wherein, The polycyclic aromatic hydrocarbon compound is added to coking raw material to carry out coking reaction, and needle coke product is prepared; the coking raw material is catalytic cracking slurry oil; 4. The method of claim 3, wherein, The polycyclic aromatic hydrocarbon compound is added to coking raw material to carry out coking reaction, and needle coke product is prepared; the coking raw material is catalytic cracking slurry oil; 5. The method of claim 3, wherein, The polycyclic aromatic hydrocarbon compound is added to coking raw material to carry out coking reaction, and needle coke product is prepared; the coking raw material is catalytic cracking slurry oil; The polycyclic aromatic hydrocarbon compound is added to coking raw material to carry out coking reaction, and needle coke product is prepared; the coking raw material is catalytic cracking slurry oil; The polycyclic aromatic hydrocarbon compound is added to coking raw material to carry out coking reaction, and needle coke product is prepared; the coking raw material is catalytic cracking slurry oil; The polycyclic aromatic hydrocarbon compound is added to coking raw material to carry out coking reaction, and needle coke product is prepared; the coking raw material is catalytic cracking slurry oil; The polycyclic aromatic hydrocarbon compound is added to coking raw material to carry out coking reaction, and needle coke product is prepared; the coking raw material is catalytic cracking slurry oil; The polycyclic aromatic hydrocarbon compound is added to coking raw material to carry out coking reaction, and needle coke product is prepared; the coking raw material is catalytic cracking slurry oil; The polycyclic aromatic hydrocarbon compound is added to coking raw material to carry out coking reaction, and needle coke product is prepared; the coking raw material is catalytic cracking slurry oil; The polycyclic aromatic hydrocarbon compound is added to coking raw material to carry out coking reaction, and needle coke product is prepared; the coking raw material is catalytic cracking slurry oil; The pol 6. The method of claim 3, wherein, The coking raw material continuously enters a coking tower, the space velocity of the coking raw material continuously entering the coking tower is 0.5-5h -1 -1, the temperature in the coking tower is 350-550℃, the pressure in the coking tower is 0.3-0.5MPa, and the coking period of the coking raw material in the coking tower is 10-40h.

7. The method of claim 3, wherein, The coking raw material continuously enters a coking tower, the space velocity of the coking raw material continuously entering the coking tower is 1-3.5h -1 , the temperature in the coking tower is 460-500℃, the pressure in the coking tower is 0.35-0.45MPa, and the coking period of the coking raw material in the coking tower is 30-40h.

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