Isotropic coke and preparation method thereof

Abstract

The invention provides isotropic coke and a preparation method thereof. The preparation method comprises the following steps: selectively hydrotreating raw oil to obtain hydrogenated residual oil; an additive is added into raw oil or hydrogenated residual oil, the additive comprises a cross-linking agent and / or a coal tar substance, when the additive comprises the cross-linking agent, a reaction is performed under the action of an acid catalyst to obtain modified oil, and when the additive only comprises the coal tar substance, mixing is performed to obtain mixed oil; performing solvent deasphalting on the modified oil or the mixed oil to obtain deasphalted oil and deoiled asphalt; and coking the deoiled asphalt to obtain the isotropic coke. The isotropic coke provided by the invention is prepared by the method. The preparation method of the isotropic coke is high in raw material applicability, high in additional value, simple in process and easy to operate, and the high-quality isotropic coke can be prepared.

Description

Technical Field

[0001] The present invention relates to an isotropic coke and a preparation method thereof, belonging to the technical field of carbon materials. Background Art

[0002] The performance of carbon products depends to a large extent on the structure and properties of the aggregate. Isotropic coke, with its unique properties, plays an important role in the carbon industry as anisotropic coke.

[0003] It is difficult to ensure the stability and safety of isotropic coke products, which severely restricts the development of the special carbon industry and industries such as the nuclear industry and the aerospace industry.

[0004] Isotropic coke generally refers to coke with an optical structure of fine-grained mosaic structure, without a single orientation. This structure determines that the properties of the coke are the same in all directions, showing macroscopic isotropic properties. Taking the coefficient of thermal expansion property as an example, isotropic coke is consistent in all directions, which is different from anisotropic coke such as needle coke, which is different in all directions, with the lowest value in the axial direction parallel to the needle texture. Isotropic coke shows anisotropy at the microscale of micrometers or even nanometers and can be graphitized to form graphite microcrystals, while being macroscopically isotropic as a whole. Therefore, isotropic coke is very suitable as the aggregate of isotropic graphite. Research shows that during the manufacturing process of isotropic graphite, after using an asphalt binder and graphitization treatment, the distribution of microcrystals inside the graphite has no orientation and has little influence on the degree of isotropy of the graphite. If the degree of isotropy of the coke particles is very good, even if molded, the degree of isotropy (also called the anisotropy coefficient) can be controlled within 1.1. Generally, the microstructures of pitch coke and petroleum coke are anisotropic. In order to produce isotropic graphite from anisotropic coke, only a cumbersome and lengthy production process can be adopted. However, using isotropic coke to produce isotropic graphite products has great advantages. Its high strength, high density, and unique isotropy have laid a technical foundation for the production of isotropic graphite, especially suitable for manufacturing high-end special graphite, such as isotropic nuclear graphite, etc.

[0005] CN114525153A discloses a method for preparing isotropic coke for negative electrode materials of lithium ion batteries. The method comprises the following steps: removing quinoline insolubles from aromatic oil by vacuum flash evaporation to obtain flash oil; mixing the flash oil with a nucleating agent in proportion, and obtaining polymerized oil after polymerization reaction; coking the polymerized oil, and then naturally cooling it in a nitrogen atmosphere to obtain isotropic coke. The method adopts a three-step method to realize the integrated preparation of isotropic coke. By adding a nucleating agent, it is ensured that mesophase spheres are easily generated during the preparation process, and the fusion between spheres is prevented by the addition of a nucleating agent, which ensures that the number of mesophase spheres is large and the distribution is uniform. At the same time, the micron-sized nucleating agent promotes the generation of a small plate structure. The isotropic coke presents a coexistence of a mosaic structure and a small plate structure at the microscopic level. However, the raw materials of this method are limited to aromatic-rich oil, and flash evaporation is required to remove quinoline insolubles, which increases operating costs. In addition, the isotropic coke has a mosaic structure and a flake structure, and the flake structure accounts for ≥50%, while the proportion of the mosaic structure is not high.

[0006] CN103693635A discloses a method for preparing isotropic coke. The method uses coal tar as raw material, purifies the coal tar by solvent thermal filtration, crosslinks and condenses the obtained refined coal tar with resin through oxidation, obtains oxidized asphalt, and prepares isotropic coke through delayed coking and calcination of the oxidized asphalt. The method has the advantages of short time consumption, high yield, no need to remove catalyst residues, and little environmental pollution. However, the method increases the crosslinking degree of coal tar raw materials through oxidation process. Although the process is simple and the raw materials are easy to obtain, the oxidation depth is uncontrollable, the reaction control window is narrow, and the oxidation process of different raw materials is also quite different, which is not conducive to the stability of the quality of isotropic coke.

[0007] CN1306070A discloses a method for preparing isotropic coke using coal tar or petroleum residue distillate as raw material. In this method, coal tar or petroleum residue distillate is placed in a reactor and heated to 120°C, and then stirred and oxygen-containing gas is introduced. The gas flow rate is 5l / h-45l / h per 100 grams of raw material, and the reaction temperature is 260-430°C. After reaching the reaction temperature, the temperature is kept constant, and the reaction time is 5-15 hours to obtain oxidized coal tar or petroleum residue distillate; the oxidized coal tar or petroleum residue distillate is coked at a temperature of 460-500°C, a pressure of 0.1-1MPa, and nitrogen protection to generate isotropic coke. This method has a simple process and is easy to operate. The optical structure of the prepared isotropic coke is a fine mosaic structure or an extremely fine mosaic structure. However, this method also uses an oxidation process to increase the steric hindrance of the raw material and form more mosaic structures, and there is also a problem of poor controllability.

[0008] CN105087033A discloses a method for preparing isotropic coke. The method comprises the following steps: a) adding an asphalt-like substance containing high quinoline insolubles and high toluene insolubles to asphalt and mixing; b) heat-treating the product obtained in step a) at 300-400°C under vacuum conditions to remove light components and obtain asphalt with a softening point of 100-200°C; c) carbonizing the asphalt product obtained in step b) at 400-500°C under pressure conditions to obtain isotropic coke green coke; d) calcining the isotropic green coke obtained in step c) at 1100-1400°C to obtain an isotropic coke product. The method can improve economic benefits by utilizing waste in the production of needle coke. However, the method promotes the formation of mosaic structure by adding an asphalt-like substance containing high quinoline insolubles and high toluene insolubles, and the compatibility problem with the raw material is prominent.

[0009] CN115651689A discloses a method for producing isotropic coke and needle coke using soft asphalt. The method uses the same raw material to pre-treat the soft asphalt by solvent sedimentation combined with "double-group double-tower continuous extraction" separation technology, and the pre-treated raw materials are coked separately to obtain different types of raw coke, so as to realize the production of two carbon products with different performances and different uses on the same production line, namely, isotropic coke with a mosaic structure and needle coke with a streamlined structure. However, the raw materials of this method are limited to soft asphalt, and it is difficult to ensure that both isotropic coke and needle coke products have high performance.

[0010] Therefore, developing a method that has strong raw material applicability and can produce high-quality isotropic coke is still one of the problems to be solved urgently in this field. Summary of the invention

[0011] In order to solve the above technical problems, the object of the present invention is to provide an isotropic coke and a preparation method thereof. The method of the present invention has strong raw material applicability and high added value, and can produce high-quality isotropic coke.

[0012] In order to achieve the above object, the first aspect of the present invention provides a method for preparing isotropic coke, which comprises the following steps:

[0013] (1) selectively hydrogenating the feedstock oil to obtain hydrogenated residue oil; adding an additive to the feedstock oil or hydrogenated residue oil, wherein the additive includes a crosslinking agent and / or a coal tar-like substance; when the additive includes a crosslinking agent, reacting under the action of an acid catalyst to obtain a modified oil; when the additive includes only a coal tar-like substance, mixing to obtain a mixed oil;

[0014] (2) subjecting the modified oil or the mixed oil to solvent deasphalting to obtain deasphalted oil and deoiled asphalt;

[0015] (3) Coking the deoiled asphalt to obtain isotropic coke.

[0016] In the above method, preferably, in step (1), the feedstock oil comprises one or a combination of catalytic slurry oil, ethylene tar, furfural extracted oil, heavy aromatic oil, coker wax oil, catalytic cycle oil, deoiled asphalt, atmospheric residue oil and vacuum residue oil, etc. More preferably, the feedstock oil is a deashed feedstock oil.

[0017] In the above method, preferably, in step (1), the sulfur mass content / residue carbon mass content in the feed oil and the hydroprocessing residue oil to which the additive is to be added is <0.018, and the ash mass content / residue carbon mass content is <0.008.

[0018] In the above method, preferably, in step (1), the cross-linking agent comprises one or a combination of terephthalic alcohol, terephthaloyl chloride and polyformaldehyde, etc. Among them, polyformaldehyde is preferably trioxymethylene.

[0019] In the above method, preferably, in step (1), the mass content of natural quinoline insolubles in the coal tar material is 6% or more. The coal tar material includes but is not limited to one or a combination of low-temperature coal tar, medium-temperature coal tar and high-temperature coal tar.

[0020] In the above method, preferably, in step (1), based on the total mass of the feedstock oil or hydrogenated residue oil being 100%, the amount of the additive added is 5-30%.

[0021] In the above method, preferably, in step (1), the acid catalyst comprises a solid acid catalyst. More preferably, the solid acid catalyst comprises one or a combination of zeolite molecular sieve, immobilized liquid acid, cation exchange resin, metal oxide, metal sulfide, metal salt, composite metal oxide, carbon-based solid acid and solid organic acid. Among them, the cation exchange resin preferably comprises a sulfonic acid cation exchange resin; the solid organic acid preferably comprises p-toluenesulfonic acid.

[0022] In the above method, preferably, in step (1), the reaction under the action of an acid catalyst specifically includes: allowing a mixture of raw oil or hydrogenated residual oil and an additive including a cross-linking agent to enter a reactor filled with a solid acid catalyst for reaction, the reaction temperature is 80-160°C, the residence time is 5-30 minutes, and a modified oil is obtained.

[0023] In the above method, preferably, step (2) specifically comprises: allowing the modified oil or the mixed oil to enter an extraction tower and a settling tower for extraction and separation, recovering the top component of the tower by solvent to obtain deasphalted oil, and recovering the bottom component of the tower by solvent to obtain deoiled asphalt, thereby completing solvent deasphalting.

[0024] In the above method, preferably, in step (2), the solvent deasphalting conditions include: the solvent used includes one or a combination of C3-C6 straight-chain and / or branched alkanes, condensate oil, light gasoline and light naphtha; the bottom temperature of the extraction tower is 50°C-200°C, the top temperature is 60-210°C, the agent-oil ratio is (4-10):1 (volume ratio), the pressure is 2.8-4.2 MPa, and the residence time is 5-40 min; the bottom temperature of the sedimentation tower is 60-210°C, the top temperature is 70-220°C, the pressure is 2.8-4.2 MPa, and the residence time is 6-20 min.

[0025] In the above method, preferably, in step (2), the yield of the deoiled asphalt is 40%-90%.

[0026] In the above method, preferably, in step (2), based on the total mass of the deoiled asphalt being 100%, the asphaltene content is 10-55%, the resin content is 5-30%, the saturated hydrocarbon content is 0-20%, and the aromatic hydrocarbon content is 20-40%.

[0027] In the above method, preferably, in step (3), the coking reaction temperature is 470-570° C., and the reaction pressure is 0.1-6 MPa.

[0028] A second aspect of the present invention provides an isotropic coke, which is prepared by the above-mentioned method for preparing the isotropic coke.

[0029] According to a specific embodiment of the present invention, preferably, the isotropic optical structure is a 100% mosaic structure, and its isotropy (CTE ratio) is less than 1.07.

[0030] The present invention provides an isotropic coke and a preparation method thereof. The method of the present invention adopts a modification-solvent deasphalting process, and while the raw material applicability is strong, a high-quality isotropic coke with a 100% mosaic structure is prepared. The additives used in the present invention to modify the raw oil or hydrogenated residue oil include a crosslinking agent and / or a coal tar substance that is relatively different from the oil-based raw material structure, so that the mixture of the raw oil or hydrogenated residue oil and the additive including the crosslinking agent can effectively remove the components with higher cracking activity after the solid acid catalyst reacts, and the modified oil is obtained. The raw oil or hydrogenated residue oil is mixed with the additive only including the coal tar substance to obtain a mixed oil. The present invention performs solvent deasphalting on the modified oil or the mixed oil, and the obtained deasphalted oil can be used as a catalytic cracking and hydrocracking raw material, and can even be used as a raw material for high-end carbon materials such as needle coke. The obtained deoiled asphalt is rich in high-activity condensed ring components, and high-quality isotropic coke can be produced after coking. The isotropic coke prepared by the present invention can be used to produce products such as energy storage materials and special graphite.

[0031] The technical solution of the present invention has at least the following beneficial effects:

[0032] 1. From the perspective of applicability, the raw materials for producing isotropic coke generally require low sulfur content and inorganic impurity content. This method is not only applicable to low-sulfur and low-ash raw materials, but also to raw materials with high sulfur content and high ash content. The high-sulfur raw materials are hydrotreated, and the sulfur content / residual carbon content is controlled below 0.018, and the ash content / residual carbon content is controlled below 0.008, which can ensure that the sulfur content of isotropic coke is below 0.5%. At present, the supply ratio of high-sulfur crude oil has accounted for more than half, and the Middle East, where crude oil production capacity is most concentrated, is also dominated by high-sulfur crude oil. With the deterioration of crude oil resources, refineries will increasingly face the problem of processing high-sulfur raw materials. Therefore, this method has high adaptability.

[0033] 2. From the yield point of view, the present invention adopts a modified-solvent deasphalting process, which effectively removes components with higher cracking activity, greatly increases the content of asphaltene in the deoiled asphalt, and reduces the content of aromatic hydrocarbons. It has the effect of increasing the molecular structure and increasing the effective components, so that the deoiled asphalt has high asphaltene and resin contents and low aromatic and saturated hydrocarbon component contents. The yield of deoiled asphalt is high and is suitable for the production of isotropic coke.

[0034] 3. From the perspective of economic benefits, the method of the present invention is actually a high value-added utilization of the heaviest components of crude oil - colloids and asphaltene. In refineries, the main destination of asphaltene is to blend road asphalt, which costs about 4,000 yuan. The price of the same coke in the same period is about 6,000 yuan. In addition, high-value gasoline and diesel can also be produced during the coking process.

[0035] In summary, the preparation method of isotropic coke of the present invention has strong raw material applicability, high added value, simple process, easy operation, can effectively remove components with high cracking activity, enrich high-activity condensed ring components, and can prepare high-quality isotropic coke with 100% mosaic structure and isotropy below 1.07, and the yield of isotropic coke is high; at the same time, the remaining component deasphalted oil can be used as a raw material for high-end carbon materials such as needle coke or used in processes such as catalytic cracking and hydrocracking, thereby improving the comprehensive utilization rate and added value of raw materials. Therefore, the method of the present invention can provide a refinery with an effective way to utilize heavy raw materials with high added value and produce high-end carbon materials, realizing the "dry squeeze" of crude oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A process flow chart of a method for preparing isotropic coke provided for a specific embodiment of the present invention.

[0037] Figure 2 This is a polarizing microscope photograph of the isotropic focus provided in Example 1.

[0038] Figure 3 This is a polarizing microscope photograph of the isotropic focus provided for Comparative Example 1. DETAILED DESCRIPTION

[0039] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0040] According to a specific embodiment of the present invention, the present invention provides a method for preparing isotropic coke, such as Figure 1 As shown, it includes the following steps:

[0041] (1) selectively hydrogenating the feedstock oil to obtain hydrogenated residue oil; adding an additive to the feedstock oil or hydrogenated residue oil, wherein the additive includes a crosslinking agent and / or a coal tar-like substance; when the additive includes a crosslinking agent, reacting under the action of an acid catalyst to obtain a modified oil; when the additive includes only a coal tar-like substance, mixing to obtain a mixed oil;

[0042] (2) subjecting the modified oil or the mixed oil to solvent deasphalting to obtain deasphalted oil and deoiled asphalt;

[0043] (3) Coking the deoiled asphalt to obtain isotropic coke.

[0044] In some embodiments, in step (1), the feedstock oil includes one or a combination of catalytic slurry oil, ethylene tar, furfural extracted oil, heavy aromatic oil, coker wax oil, catalytic cycle oil, deoiled asphalt, atmospheric residue oil and vacuum residue oil. Preferably, the feedstock oil is deashed feedstock oil. The present invention does not impose any particular restrictions on the deashing process, and the deashing process in the prior art can be used.

[0045] In some embodiments, in step (1), the sulfur mass content / residue carbon mass content in the feedstock oil and the hydrotreated residue oil to which the additive is added is less than 0.018, and the ash mass content / residue carbon mass content is less than 0.008. The present invention can directly add additives to feedstock oil that meets the above indicators. If the feedstock oil does not meet the above indicators, it is hydrotreated. The present invention does not impose any special restrictions on the hydrotreatment process, including but not limited to fixed bed hydrogenation, fluidized bed hydrogenation and suspended bed hydrogenation, as long as the prepared hydrotreated residue oil meets the above indicators.

[0046] In some embodiments, in step (1), the cross-linking agent includes one or a combination of terephthalic alcohol, terephthaloyl chloride and polyformaldehyde, etc. Among them, polyformaldehyde is preferably trioxymethylene.

[0047] In some embodiments, in step (1), the mass content of natural quinoline insolubles in the coal tar material is greater than 6%. The coal tar material includes but is not limited to one or a combination of low-temperature coal tar, medium-temperature coal tar and high-temperature coal tar.

[0048] In some embodiments, in step (1), based on the total mass of the feedstock oil or hydrogenated residue oil being 100%, the amount of the additive added is 5-30%.

[0049] In some embodiments, in step (1), the acid catalyst comprises a solid acid catalyst. Preferably, the solid acid catalyst comprises one or a combination of zeolite molecular sieve, immobilized liquid acid, cation exchange resin, metal oxide, metal sulfide, metal salt, composite metal oxide, carbon-based solid acid and solid organic acid. Among them, the cation exchange resin preferably comprises a sulfonic acid cation exchange resin; the solid organic acid preferably comprises p-toluenesulfonic acid.

[0050] In some embodiments, in step (1), the reaction under the action of an acid catalyst specifically includes: allowing a mixture of raw oil or hydrogenated residual oil and an additive including a cross-linking agent to enter a reactor filled with a solid acid catalyst for reaction, the reaction temperature is 80-160°C, the residence time is 5-30 minutes, and a modified oil is obtained.

[0051] In some embodiments, step (2) specifically includes: allowing the modified oil or the mixed oil to enter an extraction tower and a settling tower for extraction and separation, recovering the top component of the tower by solvent to obtain deasphalted oil, and recovering the bottom component of the tower by solvent to obtain deoiled asphalt, thereby completing solvent deasphalting. The system including the extraction tower, the settling tower, the solvent recovery tower, etc. used in the solvent deasphalting process of the present invention can be a system in the prior art, and the present invention does not impose any special restrictions on its structure.

[0052] In some embodiments, in step (2), the solvent deasphalting conditions include: the solvent used includes one or a combination of C3-C6 straight-chain and / or branched alkanes, condensate oil, light gasoline and light naphtha; the bottom temperature of the extraction tower is 50°C-200°C, the top temperature is 60-210°C, the agent-oil ratio is (4-10):1 (volume ratio), the pressure is 2.8-4.2 MPa, and the residence time is 5-40 min; the bottom temperature of the sedimentation tower is 60-210°C, the top temperature is 70-220°C, the pressure is 2.8-4.2 MPa, and the residence time is 6-20 min.

[0053] In some embodiments, in step (2), the yield of the deoiled asphalt is 40%-90%.

[0054] In some embodiments, in step (2), based on the total mass of the deoiled asphalt as 100%, the asphaltene content is 10-55%, the resin content is 5-30%, the saturated hydrocarbon content is 0-20%, and the aromatic hydrocarbon content is 20-40%.

[0055] In some embodiments, in step (3), the coking reaction temperature is 470-570° C., and the reaction pressure is 0.1-6 MPa. The coking process of the present invention includes but is not limited to delayed coking, kettle coking or fluidized coking, preferably fluidized coking.

[0056] like Figure 1 As shown, in the present invention, the raw oil is selected to be hydrotreated according to the sulfur content and the ash content, and the low-sulfur and low-ash raw oil or the hydrogenated residual oil that meets the low-sulfur and low-ash index requirements after hydrotreatment is modified by adding additives including cross-linking agents and / or coal tar substances. When the additive includes a cross-linking agent, it reacts under the action of an acid catalyst to obtain a modified oil. When the additive only includes coal tar substances, it is mixed to obtain a mixed oil. Then, the modified oil or the mixed oil is solvent deasphalted, and the obtained deasphalted oil can be used for catalytic cracking, hydrocracking or as a raw material for carbon materials such as needle coke. The deoiled asphalt is used as a coking raw material to produce isotropic coke. The obtained isotropic coke can be calcined and then used to produce special graphite or energy storage negative electrode materials through different processing procedures.

[0057] In the following examples and comparative examples, the mosaic structure and isotropy of the isotropic coke (green coke) were tested by the following methods.

[0058] 1. Test the isotropic coke (green coke) with a polarizing microscope. The specific steps are as follows: crush the coke sample to a particle size of about 1 mm, solidify it with resin, grind and polish the sample, and observe the microstructure.

[0059] 2. The isotropic coke (green coke) is formed into a volume of 1dm by a small vibration molding machine. 3 The coke block is calcined in a calcining furnace at 1300℃ for 2h, and then cylinders of the same diameter are drilled in the horizontal and vertical directions with a hollow drill to measure their CTE. The ratio of the two is the CTE ratio, that is, the isotropy degree.

[0060] Example 1

[0061] This embodiment provides a method for preparing isotropic coke, which comprises the following steps:

[0062] (1) Using ethylene tar from a refinery as a raw material oil, the properties of which are shown in Table 1; adding trioxymethylene in an amount of 10% by weight of the total mass of the raw material oil to the raw material oil, and the resulting mixture entering a reactor filled with a solid p-toluenesulfonic acid catalyst for reaction at a reaction temperature of 160° C. and a residence time of 5 min to obtain a modified oil;

[0063] (2) The modified oil is allowed to enter an extraction tower and a settling tower for extraction and separation, and the top component of the tower is recovered by solvent to obtain deasphalted oil, and the bottom component of the tower is recovered by solvent to obtain deoiled asphalt, thereby completing solvent deasphalting; the conditions of the solvent deasphalting include: using propane as the solvent, a solvent-oil ratio of 6, an extraction tower bottom temperature of 80°C, a tower top temperature of 90°C, a pressure of 3.5 MPa, and a residence time of 20 min; a settling tower bottom temperature of 90°C, a tower top temperature of 100°C, a pressure of 3.5 MPa, and a residence time of 15 min; the properties of the obtained deoiled asphalt are shown in Table 1;

[0064] (3) The deoiled asphalt was subjected to kettle coking at a reaction temperature of 490° C., a pressure of 0.3 MPa, and a reaction time of 10 h to obtain isotropic coke, the properties of which are shown in Table 2.

[0065] Table 1 Properties of ethylene tar and deoiled asphalt

[0066]

[0067]

[0068] Table 2 Properties of isotropic focus

[0069]

[0070] The polarizing microscope photo of the isotropic focus provided in this embodiment is as follows Figure 2 As shown in the above data, it can be seen that the isotropic optical structure provided by this embodiment is a 100% mosaic structure, and its isotropy (CTE ratio) is 1.02.

[0071] Comparative Example 1

[0072] This comparative example provides a method for preparing isotropic coke, which comprises the following steps:

[0073] Ethylene tar from a refinery was used as the raw oil, and its properties are shown in Table 3. The ethylene tar was subjected to kettle coking at a reaction temperature of 490°C, a pressure of 0.3 MPa, and a reaction time of 10 h to obtain isotropic coke, and its properties are shown in Table 4.

[0074] Table 3 Properties of ethylene tar

[0075] Analyze Project Ethylene tar Yield, % 100 Carbon residue,% 12.73 Ash content, % 0.0148 sulfur,% 0.118 Four components, % Saturation, % 0.2 Aromatics, % 68.08 Gel, % 4.53 Asphaltene, % 27.19

[0076] Table 4 Properties of isotropic focus

[0077]

[0078] The polarizing microscope photos of the isotropic focus provided in this comparative example are as follows Figure 3 As shown in the above data, it can be seen that the optical structure of the isotropic focus provided by this comparative example is not a 100% mosaic structure, but also has a wide-area structure, and its isotropy (CTE ratio) is 1.13.

[0079] Example 2

[0080] This embodiment provides a method for preparing isotropic coke, which comprises the following steps:

[0081] (1) A catalytic oil slurry which has been deashed in a refinery is used as a raw oil, and its properties are shown in Table 5; 5% of the total mass of the raw oil is added to the raw oil, and the resulting mixture is introduced into a reactor filled with a sulfonic acid cation exchange resin catalyst for reaction at a reaction temperature of 140° C. and a residence time of 10 min to obtain a modified oil;

[0082] (2) The modified oil is allowed to enter an extraction tower and a settling tower for extraction and separation, and the top component of the tower is recovered by solvent to obtain deasphalted oil, and the bottom component of the tower is recovered by solvent to obtain deoiled asphalt, thereby completing solvent deasphalting; the conditions of the solvent deasphalting include: butane as solvent, a solvent-oil ratio of 4, an extraction tower bottom temperature of 90°C, a tower top temperature of 98°C, a pressure of 4.2MPa, and a residence time of 5min; a settling tower bottom temperature of 93°C, a tower top temperature of 100°C, a pressure of 4.2MPa, and a residence time of 6min; the properties of the obtained deoiled asphalt are shown in Table 5;

[0083] (3) The deoiled asphalt was subjected to delayed coking at a reaction temperature of 500° C., a pressure of 0.3 MPa, and a time of 24 h to obtain isotropic coke, the properties of which are shown in Table 6.

[0084] Table 5 Properties of deashed catalytic oil slurry and deoiled asphalt

[0085]

[0086]

[0087] Table 6 Properties of isotropic focus

[0088]

[0089] It can be seen that the isotropic optical structure provided by this embodiment is a 100% mosaic structure, and its isotropy (CTE ratio) is 1.03.

[0090] Comparative Example 2

[0091] This comparative example provides a method for preparing isotropic coke, which comprises the following steps:

[0092] (1) A catalytic oil slurry that has been deashed in a refinery is used as a raw oil, and its properties are shown in Table 7; the raw oil enters an extraction tower and a settling tower for extraction and separation, and the top component of the tower is recovered by solvent to obtain deasphalted oil, and the bottom component of the tower is recovered by solvent to obtain deoiled asphalt, thereby completing solvent deasphalting; the conditions of the solvent deasphalting include: butane is used as a solvent, the catalyst-oil ratio is 4, the bottom temperature of the extraction tower is 90°C, the top temperature of the tower is 98°C, the pressure is 4.2MPa, and the residence time is 5min; the bottom temperature of the settling tower is 93°C, the top temperature of the tower is 100°C, the pressure is 4.2MPa, and the residence time is 6min; the properties of the obtained deoiled asphalt are shown in Table 7;

[0093] (2) The deoiled asphalt was subjected to delayed coking at a reaction temperature of 500°C, a pressure of 0.3 MPa, and a time of 24 h to obtain isotropic coke, the properties of which are shown in Table 8.

[0094] Table 7 Properties of deashed catalytic oil slurry and deoiled asphalt

[0095] Analyze Project Deashed catalytic slurry oil Deoiled Asphalt Yield, % 98 25 Carbon residue,% 23.72 30.16 Ash content, % 0.0163 0.09 sulfur,% 0.42 0.51 Four components, % Saturation, % 22.35 10.05 Aromatics, % 30.55 21.81 Gel, % 31.48 22.52 Asphaltene, % 15.62 45.62 Softening point, ℃ 189

[0096] Table 8 Properties of isotropic focus

[0097]

[0098] It can be seen that the isotropic optical structure provided in this comparative example is not a 100% mosaic structure, but also has a wide-area structure, and its isotropy (CTE ratio) is 1.10.

[0099] Example 3

[0100] This embodiment provides a method for preparing isotropic coke, which comprises the following steps:

[0101] (1) Using high-sulfur and high-ash residue oil from a refinery as raw oil, the raw oil was hydrogenated to obtain hydrogenated residue oil, the properties of which are shown in Table 9; trioxymethylene accounting for 10% of the total mass of the hydrogenated residue oil was added to the hydrogenated residue oil, and the resulting mixture was introduced into a reactor filled with a solid p-toluenesulfonic acid catalyst for reaction at a reaction temperature of 80° C. and a residence time of 30 min to obtain a modified oil, the properties of which are shown in Table 9;

[0102] (2) The modified oil is allowed to enter an extraction tower and a settling tower for extraction and separation, and the top component of the tower is recovered by solvent to obtain deasphalted oil, and the bottom component of the tower is recovered by solvent to obtain deoiled asphalt, thereby completing solvent deasphalting; the conditions of the solvent deasphalting include: pentane as solvent, a solvent-oil ratio of 9, an extraction tower bottom temperature of 50°C, a tower top temperature of 60°C, a pressure of 3MPa, and a residence time of 20min; a settling tower bottom temperature of 60°C, a tower top temperature of 70°C, a pressure of 3MPa, and a residence time of 10min; the properties of the obtained deoiled asphalt are shown in Table 9;

[0103] (3) The deoiled asphalt was subjected to delayed coking at a reaction temperature of 500°C, a pressure of 0.3 MPa, and a time of 24 h to obtain isotropic coke, the properties of which are shown in Table 10.

[0104] Table 9 Properties of hydrogenated residue oil, modified oil and deoiled asphalt

[0105]

[0106]

[0107] Table 10 Properties of isotropic focus

[0108]

[0109] It can be seen from the above data that the isotropic optical structure provided by this embodiment is a 100% mosaic structure, and its isotropy (CTE ratio) is 1.05.

[0110] Comparative Example 3

[0111] This comparative example provides a method for preparing isotropic coke, which comprises the following steps:

[0112] (1) Using high-sulfur and high-ash residue oil from a refinery as feedstock oil, the feedstock oil was hydrogenated to obtain hydrogenated residue oil, the properties of which are shown in Table 11; the hydrogenated residue oil was fed into a visbreaking reactor for visbreaking reaction, the reaction temperature was 430°C, the pressure was 0.6 MPa, the water injection rate was 5m%, and the reaction time was 10 min. After visbreaking, the material was fed into a fractionation tower to separate dry gas, gasoline fraction and visbreaking heavy oil;

[0113] (2) The viscous heavy oil is allowed to enter an extraction tower and a settling tower for extraction and separation, and the top component of the tower is recovered by solvent to obtain deasphalted oil, and the bottom component of the tower is recovered by solvent to obtain deoiled asphalt, thereby completing solvent deasphalting; the conditions of the solvent deasphalting include: pentane as solvent, a solvent-oil ratio of 9, an extraction tower bottom temperature of 50° C., a tower top temperature of 60° C., a pressure of 3 MPa, and a residence time of 20 min; a settling tower bottom temperature of 60° C., a tower top temperature of 70° C., a pressure of 3 MPa, and a residence time of 10 min; the properties of the obtained deoiled asphalt are shown in Table 11;

[0114] (3) The deoiled asphalt was subjected to delayed coking at a reaction temperature of 500°C, a pressure of 0.3 MPa, and a time of 24 h to obtain isotropic coke, the properties of which are shown in Table 12.

[0115] Table 11 Properties of Hydrogenated Residue and Deoiled Asphalt

[0116]

[0117]

[0118] Table 12 Properties of isotropic focus

[0119]

[0120] It can be seen from the above data that the isotropic optical structure provided in this comparative example is not a 100% mosaic structure, but also has a wide-area structure, and its isotropy (CTE ratio) is 1.29.

[0121] Example 4

[0122] This embodiment provides a method for preparing isotropic coke, which comprises the following steps:

[0123] (1) Using high-sulfur and high-ash residue oil from a refinery as raw oil, the raw oil was hydrogenated to obtain hydrogenated residue oil, the properties of which are shown in Table 13; adding high-temperature coal tar (the mass content of natural quinoline insoluble matter in the oil was 6% or more) accounting for 30% of the total mass of the hydrogenated residue oil to the hydrogenated residue oil, and mixing to obtain a mixed oil, the properties of which are shown in Table 13;

[0124] (2) The mixed oil is allowed to enter an extraction tower and a settling tower for extraction and separation, and the top component of the tower is recovered by solvent to obtain deasphalted oil, and the bottom component of the tower is recovered by solvent to obtain deoiled asphalt, thereby completing solvent deasphalting; the conditions of the solvent deasphalting include: pentane as solvent, a solvent-oil ratio of 10, an extraction tower bottom temperature of 200° C., a tower top temperature of 210° C., a pressure of 2.8 MPa, and a residence time of 40 min; a settling tower bottom temperature of 210° C., a tower top temperature of 220° C., a pressure of 2.8 MPa, and a residence time of 20 min; the properties of the obtained deoiled asphalt are shown in Table 13;

[0125] (3) The deoiled asphalt was subjected to delayed coking at a reaction temperature of 500°C, a pressure of 0.3 MPa, and a time of 24 h to obtain isotropic coke, the properties of which are shown in Table 14.

[0126] Table 13 Properties of hydrogenated residue oil, mixed oil and deoiled asphalt

[0127]

[0128]

[0129] Table 14 Properties of isotropic focus

[0130]

[0131] It can be seen from the above data that the isotropic optical structure provided by this embodiment is a 100% mosaic structure, and its isotropy (CTE ratio) is 1.07.

[0132] Example 5

[0133] This comparative example provides a method for preparing isotropic coke, which comprises the following steps:

[0134] (1) Using high-sulfur and high-ash residue oil from a refinery as raw oil, the raw oil was hydrogenated to obtain hydrogenated residue oil, the properties of which are shown in Table 15; adding high-temperature coal tar (the mass content of natural quinoline insoluble matter in the oil was 6% or more) accounting for 30% of the total mass of the hydrogenated residue oil to the hydrogenated residue oil, and mixing to obtain a mixed oil, the properties of which are shown in Table 15;

[0135] (2) The mixed oil is allowed to enter an extraction tower and a settling tower for extraction and separation, and the top component of the tower is recovered by solvent to obtain deasphalted oil, and the bottom component of the tower is recovered by solvent to obtain deoiled asphalt, thereby completing solvent deasphalting; the conditions of the solvent deasphalting include: pentane as solvent, a solvent-oil ratio of 10, an extraction tower bottom temperature of 200° C., a tower top temperature of 210° C., a pressure of 2.8 MPa, and a residence time of 40 min; a settling tower bottom temperature of 210° C., a tower top temperature of 220° C., a pressure of 2.8 MPa, and a residence time of 20 min; the properties of the obtained deoiled asphalt are shown in Table 15;

[0136] (3) The deoiled asphalt was subjected to fluidized coking at a reaction temperature of 550°C, a pressure of 0.1 MPa, and a time of 10 s to obtain isotropic coke, the properties of which are shown in Table 16.

[0137] Table 15 Properties of hydrogenated residue oil, mixed oil and deoiled asphalt

[0138] Analyze Project Hydrogenated residue Mixed oil Deoiled Asphalt Yield, % 90 117 43 Carbon residue,% 6.96 12.52 29.88 Ash content, % 0.05 0.09 0.14 sulfur,% 0.123 0.26 0.39 Four components, % Saturation, % 35.7 26.22 15 Aromatics, % 32.62 30.63 32.2 Gel, % 24.9 23.12 24.1 Asphaltene, % 6.78 20.03 28.7 Softening point, ℃ 150

[0139] Table 16 Properties of isotropic focus

[0140]

[0141] It can be seen from the above data that the isotropic optical structure provided by this embodiment is a 100% mosaic structure, and its isotropy (CTE ratio) is 1.03.

[0142] It can be seen from the above embodiments and comparative examples that:

[0143] (1) The isotropic coke produced by each embodiment of the present invention exhibits a 100% mosaic structure in terms of optical structure, which is a significant improvement over the mosaic structure of about 20-40% produced by direct coking. In addition, from the perspective of isotropy, the ratios of the transverse and longitudinal thermal expansion coefficients are both below 1.07, which is a significant improvement over the current situation of about 1.2 for ordinary petroleum coke. Therefore, the method of the present invention is capable of producing high-quality isotropic coke.

[0144] (2) The various embodiments of the present invention involve raw materials of different properties. Impurities in the raw materials can be removed and the sulfur content can be reduced by means of hydrogenation treatment. The effective asphaltene components can be increased by additive modification and solvent deasphalting processes, the CTE ratio of isotropic coke can be reduced, and the isotropy can be improved. The method of the present invention greatly improves the adaptability of isotropic coke raw materials and the yield of isotropic coke.

[0145] (3) Comparative Example 1 uses direct coking of crude oil, Comparative Example 2 does not perform crosslinking modification but directly performs solvent deasphalting, and Comparative Example 3 does not perform crosslinking modification but first uses visbreaking and then performs solvent deasphalting. The yield of isotropic coke in Comparative Examples 1 to 3 is significantly lower than that in Examples 1 to 3, and the prepared isotropic coke does not have a 100% mosaic structure, and the ratio of its transverse to longitudinal thermal expansion coefficient is higher than that in Examples 1 to 3.

[0146] (4) It can be seen from Examples 4 and 5 that fluidized coking is more likely to produce isotropic coke with excellent isotropy.

[0147] In summary, the present invention, based on the research of effective components of raw materials for producing isotropic coke, selectively utilizes hydrogenation treatment and modification methods to effectively improve the raw material dependence of isotropic coke, greatly improve the quality of isotropic coke products, and realize the maximum high value-added utilization of petroleum resources. The high-quality isotropic coke produced by the method of the present invention has broad application prospects in the fields of special graphite and lithium battery energy storage.

Claims

1. A method for preparing isotropic coke, wherein The following steps are involved: (1) selectively hydrogenating the feedstock oil to obtain hydrogenated residue oil; adding an additive to the feedstock oil or hydrogenated residue oil, wherein the additive includes a crosslinking agent and / or a coal tar-like substance; when the additive includes a crosslinking agent, reacting under the action of an acid catalyst to obtain a modified oil; when the additive includes only a coal tar-like substance, mixing to obtain a mixed oil; (2) subjecting the modified oil or the mixed oil to solvent deasphalting to obtain deasphalted oil and deoiled asphalt; (3) Coking the deoiled asphalt to obtain isotropic coke.

2. The method for preparing isotropic coke according to claim 1, in, In step (1), the feedstock oil comprises one or a combination of catalytic slurry oil, ethylene tar, furfural extracted oil, heavy aromatic oil, coker wax oil, catalytic cycle oil, deoiled asphalt, atmospheric residue oil and vacuum residue oil; Preferably, the raw oil is deashed raw oil.

3. The method for preparing isotropic coke according to claim 1, in, In step (1), the sulfur mass content / residue carbon mass content in the feedstock oil and the hydrogenated residue oil to which the additive is to be added is less than 0.018, and the ash mass content / residue carbon mass content is less than 0.

008.

4. The method for preparing isotropic coke according to claim 1, in, In step (1), the cross-linking agent includes one or a combination of terephthalic alcohol, terephthaloyl chloride and paraformaldehyde.

5. The method for preparing isotropic coke according to claim 1, in, In step (1), the mass content of natural quinoline insoluble matter in the coal tar material is greater than 6%.

6. The method for preparing isotropic coke according to claim 1, in, In step (1), based on the total mass of the raw oil or hydrogenated residue oil being 100%, the amount of the additive added is 5-30%.

7. The method for preparing isotropic coke according to claim 1, in, In step (1), the acid catalyst comprises a solid acid catalyst; Preferably, the solid acid catalyst comprises one or a combination of zeolite molecular sieve, immobilized liquid acid, cation exchange resin, metal oxide, metal sulfide, metal salt, composite metal oxide, carbon-based solid acid and solid organic acid.

8. The method for preparing isotropic coke according to claim 7, in, In step (1), the reaction under the action of an acid catalyst specifically includes: allowing a mixture of raw oil or hydrogenated residual oil and an additive including a cross-linking agent to enter a reactor filled with a solid acid catalyst for reaction at a reaction temperature of 80-160° C. and a residence time of 5-30 minutes to obtain a modified oil.

9. The method for preparing isotropic coke according to claim 1, in, Step (2) specifically comprises: allowing the modified oil or the mixed oil to enter an extraction tower and a settling tower for extraction and separation, recovering the top component of the tower by solvent to obtain deasphalted oil, and recovering the bottom component of the tower by solvent to obtain deoiled asphalt, thereby completing solvent deasphalting.

10. The method for preparing isotropic coke according to claim 9, in, In step (2), the solvent deasphalting conditions include: the solvent used includes one or a combination of C3-C6 straight-chain and / or branched alkanes, condensate oil, light gasoline and light naphtha; the bottom temperature of the extraction tower is 50°C-200°C, the top temperature is 60-210°C, the agent-oil ratio is (4-10):1, the pressure is 2.8-4.2MPa, and the residence time is 5-40min; the bottom temperature of the sedimentation tower is 60-210°C, the top temperature is 70-220°C, the pressure is 2.8-4.2MPa, and the residence time is 6-20min; Preferably, in step (2), the yield of the deoiled asphalt is 40%-90%; Preferably, in step (2), based on the total mass of the deoiled asphalt being 100%, the asphaltene content is 10-55%, the resin content is 5-30%, the saturated hydrocarbon content is 0-20%, and the aromatic hydrocarbon content is 20-40%.

11. The method for preparing isotropic coke according to claim 1, in, In step (3), the coking reaction temperature is 470-570°C, and the reaction pressure is 0.1-6MPa.

12. An isotropic coke, which is prepared by the method for preparing the isotropic coke according to any one of claims 1 to 11.

13. The isotropic focus according to claim 12, in, The optical structure of the isotropic focus is a 100% mosaic structure, and its isotropy is less than 1.07.

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