Aromatic hydrocarbon-rich petroleum-based impregnant asphalt and preparation method thereof

Abstract

The invention relates to aromatic hydrocarbon-rich petroleum-based impregnant asphalt and a preparation method thereof, and belongs to the technical field of asphalt chemical industry. The impregnant asphalt is prepared from oil refining and chemical byproducts in the Xinjiang region, and the performance indexes of the impregnant asphalt are as follows: the softening point is 85-100 DEG C, the toluene insoluble substance content is 15-35 wt%, the carbon residue value is 50-60 wt%, the quinoline insoluble substance content is 0-0.5 wt%, the total aromatic hydrocarbon content is 75-85%, and the hydrocarbon element ratio is 1.5-1.8. The preparation method comprises the following steps: carrying out solvent deasphalting or distillation cutting on a specific petroleum-based raw material to obtain a 350-480 DEG C aromatic hydrocarbon-rich fraction; then carrying out a thermal polycondensation reaction for 5-9 hours at the temperature of 380-410 DEG C and the pressure of 1.0-4.0 MPa in an inert atmosphere; and finally distilling to remove light components to obtain the product. According to the invention, through adaptive treatment and accurate thermal polycondensation of specific raw materials, high carbon residue of the product is synergistically realized, and the product is suitable for toluene insoluble substances and extremely low quinoline insoluble substances, and has excellent comprehensive performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of asphalt, and particularly relates to a rich-aromatic petroleum-based impregnant asphalt and a preparation method thereof. BACKGROUND

[0002] Impregnant asphalt is an indispensable densification agent for producing high-density and high-strength carbon materials (such as super-high-power graphite electrodes and special graphite), and the quality of the impregnant asphalt directly affects the porosity, mechanical strength and service life of the final product. At present, high-quality impregnant asphalt required for the production of high-end carbon products in China depends largely on imports, mainly because the performance of domestic products does not meet the standards. The mainstream domestic impregnant asphalt is mainly coal tar pitch, and the core problem of the coal tar pitch is that the quinoline insoluble (QI) content is high, the ash content and impurities are high, the flowability is poor and the permeability is poor during impregnation, and the residual impurities will deteriorate the final performance of the graphite product.

[0003] Using petroleum-based raw materials to replace coal-based raw materials is a fundamental way to solve the above problems. However, the existing petroleum-based impregnant asphalt products and their preparation technologies still have deficiencies. Some technologies focus on using catalysis, oxidation and other means to pursue excessively high softening points, resulting in an increase in QI content of the product, which loses the core value of low impurities of petroleum-based asphalt; other technologies do not fully consider the specificity of the source of raw materials, and use complex or non-optimal petroleum fractions, resulting in an unreasonable combination of key structural indicators such as toluene insoluble (TI), carbon residue value and aromatic hydrocarbon content of the prepared asphalt product. As a result, the product often performs well in one aspect, but the overall performance is poor, for example, the softening point is suitable but the coking value is low, or the flowability is good but the carbon residue is insufficient, which cannot achieve an ideal balance between impregnation effect and carbonization yield, and cannot meet the stringent requirements of high-end applications such as super-high-power graphite electrodes for impregnant asphalt, that is, "low QI, high carbon residue, suitable TI and excellent flowability". There is an urgent need in the market for a high-quality petroleum-based impregnant asphalt product with clear composition, balanced performance and stable and reliable indicators.

[0004] Therefore, it is of great significance to develop a new type of petroleum-based impregnant asphalt product based on specific high-quality raw materials, with clear and excellent comprehensive performance indicators, and to support an efficient and stable preparation method, for breaking the monopoly of foreign technology and promoting the development of China's high-end carbon industry. SUMMARY

[0005] In view of this, the purpose of this application is to provide an aromatic-rich petroleum-based impregnating agent pitch and its preparation method. This aims to solve the problem that existing impregnating agent pitch products, due to their high quinoline insoluble (QI) content and unbalanced performance indicators, fail to meet the impregnation requirements of high-end carbon materials. Furthermore, it synergistically leverages the high residual carbon, high aromatic content, excellent flowability, and permeability brought by specific aromatic-rich raw materials, thereby obtaining a petroleum-based impregnating agent pitch with superior comprehensive performance, particularly suitable for impregnating high-power and ultra-high-power graphite electrodes. The specific technical solution is as follows:

[0006] A petroleum-based impregnating agent for aromatic hydrocarbons, which is produced from a by-product of oil refining and chemical production in Xinjiang, has the following performance indicators: softening point of 85-100℃, toluene-insoluble content of 15-35wt%, carbon residue of 50-60wt%, quinoline-insoluble content of 0-0.5wt%, total aromatic hydrocarbon content of 75-85%, and carbon-hydrogen ratio of 1.5-1.8.

[0007] Furthermore, the aforementioned refining and chemical byproducts in Xinjiang are furfural extract oil from the reduced-pressure line 3 or the reduced-pressure line 4.

[0008] Furthermore, a method for preparing aromatic petroleum-based impregnating bitumen includes the following steps: S1. Solvent deasphalting or distillation cutting of petroleum-based feedstock to obtain aromatic-rich fractions; S2. The aromatic fraction obtained in step S1 is subjected to thermal polycondensation reaction under an inert atmosphere; S3. The reaction product obtained in step S2 is distilled to remove the light components, thereby obtaining the impregnating agent asphalt.

[0009] Furthermore, in step S1 of the above method, the raw material is a by-product of oil refining and chemical industry in Xinjiang.

[0010] Furthermore, in step S1 of the above method, the solvent used for solvent deasphalting is butane or a mixture of butane and pentane.

[0011] Furthermore, in step S1 of the above method, the boiling range of the aromatic-rich fraction is 350~480℃.

[0012] Furthermore, in step S2 of the above method, the temperature of the thermal polycondensation reaction is 380~410℃, the pressure is 1.0~4.0MPa, and the reaction time is 5~9h.

[0013] Furthermore, in step S2 of the above method, the inert gas is nitrogen.

[0014] Furthermore, in this paper, the numerical ranges involved all include endpoint values ​​and cover any subranges within that range.

[0015] The application provides a kind of aromatic hydrocarbon-rich petroleum-based impregnant pitch and a preparation method thereof, and has the following beneficial effects: I. The product of the present application helps to improve the performance imbalance of existing products through the synergistic effect of its performance indicators. The higher aromatic content and suitable toluene insoluble content help to form good fluidity and permeability at the impregnation temperature, promoting the full filling of the carbon blank pores. The higher carbon residue value is beneficial to obtaining higher densification efficiency during carbonization. At the same time, the lower quinoline insoluble and ash content helps to reduce the adverse effects on the structure of carbon products.

[0016] II. The present application uses Xinjiang oil refining chemical by-products as raw materials, which have the characteristics of high aromatic content and low impurity content. Based on this specific raw material, combined with the appropriate purification and thermal polycondensation process, it helps to form the high aromatic content, ideal carbon-hydrogen ratio and good coking performance required by the present application, so that the product performance has a stable raw material basis, thereby distinguishing from the asphalt products prepared by using ordinary or complex raw materials.

[0017] III. The present application adopts the process route of "solvent deasphalting / distillation cutting and enriching ideal fraction" combined with "thermal polymerization under nitrogen protection". This process helps to remove solid impurities from the raw material, and by controlling the degree of polycondensation, the chemical reactivity of the raw material is matched, so that the composition characteristics of the raw material are effectively converted into product performance advantages, which is beneficial to ensure the consistency of product quality between batches and improve the performance fluctuation problem caused by poor raw material adaptability. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the present application will be described clearly and completely in combination with examples. If the specific conditions are not specified in the examples, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be purchased on the market.

[0019] Example 1 A preparation method of an aromatic hydrocarbon-rich petroleum-based impregnant pitch, comprising the following steps: S1: weigh 1.0 kg of Xinjiang-produced reduced three-line furfural extract oil, and stir it with n-butane solvent (raw material to solvent mass ratio 1:4) in a mixer at 60℃ for 30 minutes, then separate and collect the deasphalted oil phase after layering. The obtained deasphalted oil is transferred into a distillation device, heated and warmed, and the aromatic-rich fraction with a boiling range of 350℃ to 480℃ is cut to obtain a purified raw material; S2: Put all the purified raw materials obtained in S1 into a 2L high-pressure reactor, seal it, and replace the air in the reactor with nitrogen three times; under the protection of continuous nitrogen flow, heat the system to 390°C at a rate of 5°C / min; stabilize the absolute pressure in the reactor at 4.0 MPa by supplementing nitrogen, set the stirring speed to 200 rpm, and react for 5 hours under these conditions; S3: Transfer the product obtained after the reaction in S2 to an atmospheric distillation device, distill it at 260°C for 1 hour to remove light components, and then cool the product to room temperature to obtain a petroleum-based impregnant asphalt sample rich in aromatic hydrocarbons.

[0020] Example 2 S1: Weigh 1.0 kg of furfural extract oil produced in Xinjiang, mix it with n-butane solvent (raw material to solvent mass ratio 1:4) in a mixer at 60°C for 30 minutes, then separate and collect the deasphalted oil phase after static layering; transfer the obtained deasphalted oil into a distillation device, heat it to a certain temperature, and cut the aromatic hydrocarbon-rich fraction with a boiling range of 350-480°C to obtain purified raw materials; S2: Put the purified raw materials obtained in S1 into a high-pressure reactor, heat it to 410°C at a rate of 5°C / min under nitrogen protection, control the absolute pressure at 1.0 MPa, keep the stirring speed at 200 rpm, and react for 7 hours; S3: Transfer the product obtained after the reaction in S2 to an atmospheric distillation device, distill it at 260°C for 1 hour to remove light components, and then cool the product to room temperature to obtain a petroleum-based impregnant asphalt sample rich in aromatic hydrocarbons.

[0021] Example 3 A method for preparing a petroleum-based impregnant asphalt rich in aromatic hydrocarbons, comprising the following steps: S1: Weigh 1.0 kg of furfural extract oil produced in Xinjiang, mix it with n-butane solvent (raw material to solvent mass ratio 1:4) in a mixer at 60°C for 30 minutes, then separate and collect the deasphalted oil phase after static layering; transfer the obtained deasphalted oil into a distillation device, heat it to a certain temperature, and cut the aromatic hydrocarbon-rich fraction with a boiling range of 350-480°C to obtain purified raw materials; S2: Put the purified raw materials obtained in S1 into a high-pressure reactor, heat it to 410°C at a rate of 5°C / min under nitrogen protection, control the absolute pressure at 1.0 MPa, keep the stirring speed at 200 rpm, and react for 7 hours; S3: Transfer the product obtained after the reaction in S2 to an atmospheric distillation device, distill it at 260°C for 1 hour to remove light components, and then cool the product to room temperature to obtain a petroleum-based impregnant asphalt sample rich in aromatic hydrocarbons.

[0022] The raw material sources in the above embodiments: the reduced three-line furfural extract oil (quinoline insoluble content <0.1 wt%) is from Karamay Petrochemical Co., Ltd., PetroChina; the reduced four-line furfural extract oil (total aromatic hydrocarbon content ~ 79%) is from Dushanzi Petrochemical Branch Co., Ltd., PetroChina; n-butane (industrial grade, purity ≥ 95%) is purchased from Zibo Qixiang Tengda Chemical Co., Ltd.; nitrogen (purity ≥ 99.99%) is purchased from Urumqi Guanghui Liquefied Natural Gas Development Co., Ltd.

[0023] Comparative Example 1 In S1, replace the 1.0 kg of catalytic cracking slurry oil with a total aromatic hydrocarbon content of 65%; the remaining components, proportions and operation steps are the same as in Example 1.

[0024] Comparative Example 2 In S1, omit the solvent deasphalting and fraction cutting steps, and directly use the original raw material; the remaining components, proportions and operation steps are the same as in Example 1.

[0025] Comparative Example 3 In S2, change to heating to 430℃ at 5℃ / min under normal pressure (pressure 0.10-0.11 MPa) for 5 hours; the remaining components, proportions and operation steps are the same as in Example 1.

[0026] According to the National Standard for Testing of Petroleum Pitch and Related Products, performance testing of the samples obtained in Examples 1-3 and Comparative Examples 1-3 was carried out under standard experimental conditions of temperature 23±2℃ and relative humidity 50±10%. Each test was repeated three times, and the average value was taken as the final result.

[0027] I. Softening Point Determination According to GB / T 4507-2014 "Determination of Softening Point of Pitch - Ring and Ball Method". The sample was heated and melted, then poured into a brass ring, cooled and placed on a steel ball and ball seat frame of a specified size, heated at a rate of 5℃ / min in distilled water at 5℃, and the temperature at which the steel ball fell through the sample ring to the bottom plate was measured. The average of two parallel test results was taken as the determination value.

[0028] II. Toluene Insoluble Content Determination According to GB / T 2292-2018 "Determination of Toluene Insoluble Content of Coking Products". About 1g of sample was accurately weighed and placed in a filter paper cylinder, and extracted with toluene in a Soxhlet extractor until the toluene flowing out was colorless. The filter paper cylinder was removed, dried and cooled, then weighed and the percentage of insoluble matter in the original sample was calculated; the results are shown in Table 1.

[0029] III. Quinoline insoluble content determination was carried out according to GB / T 2293-2019 "Coking product quinoline insoluble test method". About 1 g of sample was accurately weighed, placed in a beaker, hot quinoline solvent was added, after stirring and dissolving, the filtrate was washed with hot quinoline until it was colorless, then washed with acetone, dried, cooled and weighed, and the mass percentage of insoluble matter in the original sample was calculated; the results are shown in Table 1.

[0030] IV. Carbon residue value determination According to SH / T 0170-2002 "Petroleum product carbon residue determination method", an appropriate amount of sample was weighed into a specified porcelain crucible, heated, evaporated, cracked and calcined in a Con's carbon residue determination instrument under the condition of no air, and the carbon residue value was expressed by the percentage of the mass of the residue in the mass of the original sample; the results are shown in Table 1.

[0031] V. Ash content determination According to GB / T 2295-2008 "Coking product ash content determination method", the sample was placed in a porcelain crucible with constant weight, carefully carbonized on an electric furnace, then placed in a muffle furnace at (825±25) °C and calcined to constant weight, cooled and weighed, and the ash content was expressed by the percentage of the mass of the residue in the mass of the original sample; the results are shown in Table 1.

[0032] VI. Total aromatic content determination According to SH / T 0509-2010 "Petroleum pitch component determination method", an alumina adsorption chromatographic column was used, different polarity solvents (n-heptane, toluene-ethanol, toluene, toluene-ethanol) were used to flush in turn, and the pitch sample was separated into four chemical components: saturates, aromatics, resins and asphaltenes, and the content of aromatics was the total aromatic content, expressed by mass percentage; the results are shown in Table 1.

[0033] VII. Carbon-hydrogen element ratio determination A Vario EL cube type element analyzer was used. High temperature combustion method was used, about 2 mg of sample was accurately weighed and instantaneously combusted in a high temperature oxygen stream, the generated CO2 and H2O were separated by a special adsorption tube, and then detected by a thermal conductivity detector, the mass percentages of carbon and hydrogen elements in the sample were calculated by external standard method, and the ratio (C / H) was calculated; the results are shown in Table 1.

[0034] Table 1 Test results one (product yield and purity)

[0035] From the above results, it can be seen that the aromatic-rich petroleum-based impregnant pitch prepared in Examples 1 to 3 exhibits excellent and balanced overall performance: not only does it meet the requirements of a suitable softening point and high carbon residue value for an impregnant, but more importantly, it forms an excellent combination of toluene insoluble content, extremely low quinoline insoluble and ash content, while achieving a high aromatic content and ideal carbon-hydrogen element ratio. The realization of this unique performance spectrum is rooted in the organic combination of "Xinjiang-specific aromatic-rich raw material" and "adapted purification-thermal polymerization process". The specific raw material provides a molecular basis of high aromatic content and low impurities; the solvent deasphalting and fraction cutting purification process further removes solid impurities and unsuitable components; and the subsequent thermal polymerization reaction under pressure precisely promotes the condensation of aromatic molecules, significantly improves the carbon residue value and adjusts the TI, while protecting the condensed ring aromatic structure and effectively inhibiting the generation of QI.

[0036] Comparative Example 1 uses a common catalytic cracking slurry oil with a lower aromatic content as the raw material. Although it undergoes the same purification and polymerization process as Example 1, its aromatic content and C / H ratio still cannot meet the requirements of the present application, and the carbon residue value is too low

[0037] Comparative Example 2 omits the purification step of the raw material. As a result, the solid impurities and primary QI derived from the raw material cannot be effectively removed, and the ash and QI content is severely over-standard.

[0038] Comparative Example 3 performs the thermal polymerization reaction under normal pressure. Its product exhibits a serious performance imbalance: the toluene insoluble content is too low and the carbon residue value does not meet the standard. This proves that a certain pressure environment is crucial for promoting deep condensation reactions, achieving a balance between high carbon residue value and moderate toluene insoluble content. Normal pressure conditions cannot provide enough reaction driving force to achieve the desired overall performance.

[0039] The above-described examples only express the preferred embodiments of the present application, which are described in detail and specifically, but are not intended to limit the present application. It should be noted that for those skilled in the art, the present application can also have various changes and modifications, and any modification, equivalent replacement, improvement, etc. made within the concept and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An aromatic-rich petroleum-based impregnant bitumen, characterized in that, The Xinjiang oil refining chemical by-product is prepared, and performance indexes thereof meet: a softening point is 85-100 DEG C, a toluene insoluble is 15-35wt%, a carbon residue value is 50-60wt%, a quinoline insoluble is 0-0.5wt%, a total aromatic hydrocarbon content is 75-85%, and a carbon hydrogen element ratio is 1.5-1.

8.

2. The aromatic-rich petroleum-based impregnant bitumen according to claim 1, characterized in that, The Xinjiang oil refining chemical by-product is a third-line furfural extract oil or a fourth-line furfural extract oil.

3. A process for the preparation of an aromatic-rich petroleum-based impregnant bitumen according to any one of claims 1-2, characterized in that, The method comprises the following steps: S1. Solvent deasphalting or distillation cutting is performed on a petroleum-based raw material to cut a rich aromatic hydrocarbon fraction; S2. The rich aromatic hydrocarbon fraction obtained in step S1 is subjected to a thermal polycondensation reaction under pressurized conditions under the protection of an inert atmosphere; S3. The reaction product obtained in step S2 is distilled to remove light components to obtain the impregnating agent pitch.

4. The raw material is a Xinjiang oil refining chemical by-product.

5. A process for the preparation of a rich-aromatics petroleum-based impregnant bitumen according to claim 3, characterized in that, In the S1, the solvent used for the solvent deasphalting is butane or a mixed solvent of butane and pentane.

6. A process for the preparation of a rich-aromatics petroleum-based impregnant bitumen according to claim 3, characterized in that, In the S1, the boiling range of the cut rich aromatic hydrocarbon fraction is 350-480 DEG C.

7. A process for the preparation of a rich-aromatics petroleum-based impregnant bitumen according to claim 3, characterized in that, In the S2, the temperature of the thermal polycondensation reaction is 380-410 DEG C, the pressure is 1.0-4.0 MPa, and the reaction time is 5-9h.

8. A process for the preparation of a rich-aromatics petroleum-based impregnant bitumen according to claim 3, characterized in that, In the S2, the inert gas is nitrogen.

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