Preparation method of refined asphalt

Abstract

The invention discloses a preparation method of refined asphalt, which comprises the following steps: (1) dipping a catalyst into a metal chloride solution, and roasting to obtain a catalyst precursor; (2) uniformly mixing the catalyst prepared in the step (1) with a raw material and a solvent, and then putting the mixture into a reaction kettle; (3) carrying out atmospheric distillation on a pretreated product obtained in the step (2) to remove the solvent; and (4) mixing a product obtained in the step (3) with the solvent, extracting and filtering, and carrying out atmospheric distillation to remove the solvent, so as to obtain the target material refined asphalt.

Description

Technical Field

[0001] The invention relates to a method for preparing refined asphalt, and belongs to the field of coal chemical industry. Background Art

[0002] Mesophase pitch is considered to be a high-quality precursor for producing high-quality carbon materials, such as mesophase pitch-based carbon fibers, foamed carbon, and electrode negative materials, due to its wide sources, high residual carbon rate, and easy graphitization. High-quality mesophase pitch precursors require uniform reaction activity, narrow molecular weight distribution, appropriate amounts of short-chain alkanes and cycloalkane structures, and low ash content, but industrial raw materials cannot meet the above requirements and need to be processed.

[0003] CN111826188A discloses "a raw material asphalt for carbon-based new materials and its production process", which prepares a high-quality asphalt raw material with narrow molecular weight distribution, moderate molecular weight, highly ordered molecular arrangement, good fluidity, excellent aggregate structure and stable thermal reaction activity through multi-stage extraction, hydrogenation, distillation and other processes.

[0004] CN116640592A discloses "a method for preparing an intermediate phase asphalt precursor", which adopts solvent extraction + centrifugal separation to extract polycyclic aromatic hydrocarbons, separate quinoline heavy residue, and remove inorganic ash at the same time, thereby obtaining a low-cost, low-ash intermediate phase asphalt precursor, and at the same time produces coal tar pitch with high softening point and high coking value, so that coal liquefaction asphalt is fully utilized.

[0005] CN108102679B discloses a "coal tar refining method for synthesizing mesophase asphalt". A solvent is added to the asphalt, stirred under normal pressure, allowed to stand, and layered to separate the effective components of the coal tar from impurities such as coal powder and coke particles remaining in the original coal tar. The refined coal tar can be used as a raw material for high-end carbon materials to meet the requirements for the subsequent preparation of high value-added products.

[0006] However, the above-mentioned prior art separates the raw materials through physical methods such as extraction, sedimentation, centrifugation, etc., but cannot fundamentally change the molecular structure of the asphalt, and the yield is low. Summary of the invention

[0007] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing refined asphalt, which is used to solve the problems of large difference in reaction activity between light and heavy components of asphalt, low content of short-chain alkanes and cycloalkane structures, and high ash content. The method is simple to operate, has a high asphalt yield and low cost.

[0008] In order to achieve the above-mentioned invention object, the present invention adopts the following technical solutions:

[0009] A method for preparing refined asphalt, characterized in that the preparation method comprises the following steps:

[0010] Step (1), impregnating a porous substrate with a loaded metal halide, and drying the obtained impregnated substrate, and calcining under a protective atmosphere to obtain a modified catalyst; wherein the content of the metal halide is 0-10wt% based on the dry basis of the impregnated substrate; and when the content of the metal halide is 0, the modified catalyst is the porous substrate or the calcined porous substrate;

[0011] Step (2), mixing the asphalt-containing raw material and the solvent oil in a mass ratio of 1:0.1-15 and placing the mixture in a reaction kettle, adding 1-25% by mass of the modified catalyst obtained in step (1), and conducting a catalytic reaction at 320-480° C. for 0.5-5 h to obtain a pretreated product;

[0012] Step (3), distilling the pre-treated product obtained in step (2) to separate the solvent oil and obtain a residual product;

[0013] Step (4), mixing the remaining product obtained in step (3) with an extraction solvent to extract the refined asphalt therein, and performing solid-liquid separation, wherein the filtrate is distilled to recover the extraction solvent, and the obtained solid product is the refined asphalt.

[0014] In step (1) of the present invention, the porous substrate is impregnated with a loaded metal halide. The specific impregnation is well known in the art, for example, the porous substrate is impregnated with 0.01 to 0.5 mol L -1 For example, 0.05, 0.1 or 0.2 mol L -1 The metal chloride solution is stirred and evaporated to dryness in a water bath at 60-100°C to ensure full loading.

[0015] In step (1) of the present invention, when the content of the metal halide is 0, the modified catalyst is the porous matrix or the calcined porous matrix, that is, the porous matrix can be directly used as a catalyst in step (2).

[0016] In a preferred embodiment, in step (1), the porous matrix is ​​selected from one or more of zirconium oxide, bentonite, activated carbon, sepiolite, titanium dioxide and diatomaceous earth; preferably one or more of zirconium oxide, bentonite, activated carbon and sepiolite. In some embodiments, the particle size of the porous matrix can be 10-100 microns.

[0017] In a preferred embodiment, in step (1), the selected metal halide is a metal chloride, preferably one or more selected from AlCl3, FeCl3, CuCl2, ZnCl2, MnCl2 and CoCl2.

[0018] In a preferred embodiment, in step (1), the content of the metal halide is 0.5-5 wt %, such as 1, 2, 3 or 4 wt %.

[0019] Preferably, in step (1), the calcination is carried out at 600-1000°C, such as 700, 800 or 900°C, and in a protective atmosphere such as a nitrogen atmosphere for 6-20 hours, such as 10, 12, 15 or 18 hours to obtain a modified catalyst.

[0020] In step (2) of the present invention, a catalyst is added to the mixture of the asphalt-containing raw material and solvent oil to carry out catalytic coking and chain scission reactions, and the coking catalyst can also adsorb and purify the raw material.

[0021] In a preferred embodiment, in step (2), the asphalt-containing raw material is selected from one or more of coal tar pitch, catalytic cracking sedimentation oil, ethylene tar, coal liquefaction pitch and FCC slurry oil.

[0022] In a preferred embodiment, in step (2), the solvent oil is one or more of wash oil and anthracene oil.

[0023] In a preferred embodiment, in step (2), the asphalt-containing feedstock and solvent oil are uniformly mixed in a mass ratio of 1:0.5 to 10, such as 1:1, 1:2, 1:3, 1:5 or 1:8, to reduce the viscosity of the system and the concentration of aromatic free radicals. It can be understood in the art that too little solvent oil is not conducive to subsequent coking purification and adsorption, and too much solvent oil is not conducive to controlling cost efficiency.

[0024] In a preferred embodiment, in step (2), the modified catalyst is added in a mass ratio of 1 to 15%, such as 2%, 5%, 7%, 10% or 12%, of the mixture of the asphalt-containing feedstock and the solvent oil.

[0025] In a preferred embodiment, in step (2), the catalytic reaction is carried out at 340-450°C, such as 360, 380, 400 or 420°C, for 0.5-3h, such as 1 or 2h, to obtain a pretreated product.

[0026] In step (3) of the present invention, the pretreated product obtained in step (2) is subjected to distillation separation to remove the solvent oil; in a preferred embodiment, in step (3), when performing distillation separation, the pretreated product obtained in step (2) is distilled at 300-400°C, such as 320, 350 or 380°C, to separate the solvent oil; it is understood in the art that the distillation temperature can be adjusted accordingly according to the specific solvent oil selection, which is well known in the art.

[0027] In step (4) of the present invention, an extraction solvent is added to the residual product of the distillation in step (3) to extract the refined asphalt therein; in a preferred embodiment, in step (4), the extraction solvent is selected from one or more of tetrahydrofuran, pyridine, cyclohexane, toluene and xylene.

[0028] In a preferred embodiment, in step (4), the residual product obtained in step (3) is mixed with an extraction solvent in a mass ratio of 1:5 to 20, such as 1:8, 1:10 or 1:15; it can be understood in the art that too little extraction solvent is not conducive to the sufficient extraction of refined asphalt, and too much extraction solvent is not conducive to controlling cost efficiency.

[0029] In a preferred embodiment, in step (4), the filtrate is distilled at 60-200° C., such as 80, 100, or 150° C., to separate the extraction solvent and obtain refined asphalt. The distillation temperature can be adjusted accordingly according to the specific extraction solvent selection, which is well known in the art.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] The method for preparing refined asphalt of the present invention preheats the raw asphalt through a catalytic coking adsorption purification process, so that the high-reactivity components therein are quickly coked and removed, the molecular weight distribution is narrowed, the long side chains are interrupted, and more methyl hydrogen and methylene hydrogen are obtained. At the same time, the excellent adsorption performance of the catalyst can adsorb stubborn ash to achieve the effect of deep deashing.

[0032] The present invention adopts catalyst and asphalt pretreatment to obtain refined asphalt, and the molecular weight distribution is more concentrated, the long-chain hydrogen is reduced, the methyl hydrogen, methylene hydrogen and cycloalkane hydrogen are increased, the aromaticity is reduced, the fluidity of the asphalt is improved, and the deep deashing is below 100ppm. The mosaic and fine fiber structures of the intermediate phase asphalt formed by the refined asphalt under the heat treatment workbench are reduced, and the wide-area streamlined structure is increased.

[0033] In addition, the present invention modifies the catalyst and regulates the catalyst composition to make it more suitable for the reaction of asphalt; at the same time, before the reaction, by adding solvent oil, the viscosity of the system and the concentration of aromatic free radicals are reduced, and the selective reaction of the catalyst can be promoted; in addition, while regulating the molecular composition of asphalt, the present invention achieves deep deashing, which meets the requirements for preparing high-end carbon materials.

[0034] The present invention adopts a catalytic coking adsorption purification process to optimize the molecular composition of the raw asphalt, deeply deash the asphalt to below 100 ppm, reduce the mosaic structure of the intermediate phase asphalt obtained from the refined asphalt by 70.59%, reduce the fine fiber structure by 74.63%, increase the wide-area streamlined structure by 362.5%, and make the intermediate phase molecules more orderly. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a scanning electron microscope image of bentonite calcined at 900° C. in a nitrogen atmosphere in Example 1;

[0036] Figure 2 This is a polarizing microscope photograph of the refined asphalt obtained in Example 1 being thermally condensed into mesophase asphalt. DETAILED DESCRIPTION

[0037] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiment of the present invention will be further described below in conjunction with the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0038] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values, such as values ​​of ±10% of the endpoint values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other.

[0039] It should be noted that the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatus.

[0040] Example 1

[0041] Step 1: Mix bentonite with 0.05 mol L -1The ZnCl2 solution was stirred in a water bath at 70°C for 12h, and then calcined at 900°C in a N2 atmosphere for 12h to obtain a modified catalyst. Step 2: Mix 50g of coal liquefaction asphalt and 50g of anthracene oil evenly and place them in a reactor, add the modified bentonite obtained in step 1 in a mass ratio of 3wt.%, and react at 400°C for 0.5h to obtain a preliminary pretreated product. Step 3: Distill the pretreated product obtained in step 2 at 360°C under atmospheric pressure until no solvent flows out. Step 4: Mix the product obtained in step 3 with xylene in a mass ratio of 1:10, extract and filter, wherein the filtrate is distilled at atmospheric pressure at 139°C until no solvent flows out, and the obtained solid product is refined asphalt, the light component (100-768m / z) content is 73.94%, the heavy component (1152-1700m / z) is 5.79%, H α The content is 19.88%, H N The ash content is 86 ppm, the mosaic content of the intermediate phase asphalt obtained from the refined asphalt is 5%, and the wide-area streamlined content is 63%.

[0042] Example 2

[0043] Step 1: Mix activated carbon with 0.03 mol L -1 The FeCl3 solution was stirred in a water bath at 70°C for 12h, and then calcined at 800°C in a N2 atmosphere for 12h to obtain a modified catalyst. Step 2. 50g of ethylene tar and 30g of anthracene oil were evenly mixed and placed in a reactor, and the modified activated carbon obtained in step 1 was added in a mass ratio of 7wt.%, and reacted at 380°C for 1h to obtain a preliminary pretreatment product. Step 3. The pretreatment product obtained in step 2 was distilled at 360°C under normal pressure until no solvent flowed out. Step 4. The product obtained in step 3 was mixed and stirred with pyridine in a mass ratio of 1:5, extracted and filtered, and the filtrate was distilled at normal pressure at 115.3°C until no solvent flowed out. The obtained solid product was refined asphalt, and the content of light components (100-768m / z) was 68.32%, the heavy components (1152-1700m / z) was 7.62%, and H α The content is 20.45%, H N The ash content is 9.87%, the ash content is 120 ppm, and the mosaic content of the intermediate phase asphalt obtained from the refined asphalt is 7%, and the wide-area streamlined content is 67%.

[0044] Example 3

[0045] Step 1: ZrO2 and 0.1 mol L -1The AlCl3 solution was stirred in a water bath at 80°C for 12h, and then calcined at 800°C in a N2 atmosphere for 12h to obtain a modified catalyst. Step 2. 50g of coal liquefaction asphalt was evenly mixed with 30g of wash oil and placed in a reactor, and the modified ZrO2 obtained in step 1 was added in a mass ratio of 3wt.%, and reacted at 430°C for 1h to obtain a preliminary pretreatment product. Step 3. The pretreatment product obtained in step 2 was distilled at 300°C under atmospheric pressure until no solvent flowed out. Step 4. The product obtained in step 3 was mixed and stirred with cyclohexane in a mass ratio of 1:10, extracted and filtered, and the filtrate was distilled at atmospheric pressure at 139°C until no solvent flowed out. The obtained solid product was refined asphalt, and the content of light components (100-768m / z) was 76.88%, the heavy components (1152-1700m / z) was 3.85%, and H α The content is 23.34%, H N The ash content is 12.15%, the ash content is 77 ppm, the mosaic content of the intermediate phase asphalt obtained from the refined asphalt is 4%, and the wide-area streamlined content is 72%.

[0046] Example 4

[0047] Step 1: Mix sepiolite with 0.01 mol L -1 The CuCl2 solution was stirred in a water bath at 90°C for 12h, and then calcined at 700°C in a N2 atmosphere for 12h to obtain a modified catalyst. Step 2. 50g of coal liquefaction asphalt was evenly mixed with 80g of anthracene oil and placed in a reactor, and the modified sepiolite obtained in step 1 was added in a mass ratio of 1wt.%, and reacted at 430°C for 2h to obtain a preliminary pretreatment product. Step 3. The pretreatment product obtained in step 2 was distilled at 360°C under normal pressure until no solvent flowed out. Step 4. The product obtained in step 3 was mixed and stirred with tetrahydrofuran in a mass ratio of 1:5, extracted and filtered, and the filtrate was distilled at normal pressure at 66°C until no solvent flowed out. The obtained solid product was refined asphalt, and the content of light components (100-768m / z) was 75.32%, the heavy components (1152-1700m / z) was 3.12%, and H α The content is 21.88%, H N The ash content is 9.54%, the ash content is 102 ppm, the mosaic content of the intermediate phase asphalt obtained from the refined asphalt is 9%, and the wide-area streamlined content is 77%.

[0048] Example 5

[0049] Step 1: Mix bentonite with 0.1 mol L -1The FeCl3 solution was stirred in a water bath at 80°C for 12h, and then calcined at 800°C in a N2 atmosphere for 12h to obtain a modified catalyst. Step 2. 50g of coal liquefaction asphalt and 100g of anthracene oil were mixed evenly and placed in a reactor, and the modified bentonite obtained in step 1 was added in a mass ratio of 3wt.%, and reacted at 450°C for 2h to obtain a preliminary pretreatment product. Step 3. The pretreatment product obtained in step 2 was distilled at 360°C under atmospheric pressure until no solvent flowed out. Step 4. The product obtained in step 3 was mixed and stirred with toluene in a mass ratio of 1:20, extracted and filtered, and the filtrate was distilled at atmospheric pressure at 110.6°C until no solvent flowed out. The obtained solid product was refined asphalt, and the content of light components (100-768m / z) was 78.52%, the heavy components (1152-1700m / z) was 2.77%, and H α The content is 24.52%, H N The ash content is 14.25%, the ash content is 61 ppm, and the mosaic content of the intermediate phase asphalt obtained from the refined asphalt is 3%, and the wide-area streamlined content is 82%.

[0050] Example 6

[0051] Step 1: Mix activated carbon with 0.1 mol L -1 The CuCl2 solution was stirred in a water bath at 90°C for 12h, and then calcined at 600°C in a N2 atmosphere for 12h to obtain a modified catalyst. Step 2. 50g of coal liquefaction asphalt was evenly mixed with 150g of wash oil and placed in a reactor, and the modified activated carbon obtained in step 1 was added in a mass ratio of 5wt.%, and reacted at 380°C for 3h to obtain a preliminary pretreatment product. Step 3. The pretreatment product obtained in step 2 was distilled at 300°C under atmospheric pressure until no solvent flowed out. Step 4. The product obtained in step 3 was mixed and stirred with xylene in a mass ratio of 1:5, extracted and filtered, and the filtrate was distilled at atmospheric pressure at 139°C until no solvent flowed out. The obtained solid product was refined asphalt, and the content of light components (100-768m / z) was 69.37%, the heavy components (1152-1700m / z) was 8.22%, and H α The content is 21.21%, H N The ash content is 12.96%, the ash content is 55 ppm, the mosaic content of the intermediate phase asphalt obtained from the refined asphalt is 9%, and the wide-area streamlined content is 69%.

[0052] Example 7

[0053] The difference from Example 1 is that the bentonite in step 1 is not modified and is directly used as a catalyst in step 2.

[0054] The obtained refined asphalt has a light component (100-768 m / z) content of 75.24%, a heavy component (1152-1700 m / z) of 6.15%, and a H αThe content is 19.46%, H N The ash content is 8.35%, the ash content is 95ppm, and the mosaic content of the intermediate phase asphalt obtained from the refined asphalt is 6%, and the wide-area streamlined content is 62%.

[0055] It can be seen from the above embodiments that the present invention adopts catalyst and asphalt pretreatment to obtain refined asphalt, the molecular weight distribution is more concentrated, the long-chain hydrogen is reduced, the methyl hydrogen, methylene hydrogen and cycloalkane hydrogen are increased, the aromaticity is reduced, the fluidity of the asphalt is improved, and the deep deashing is below 100 ppm. The mosaic and fine fiber structures of the intermediate phase asphalt formed by the refined asphalt under the heat treatment workbench are reduced, and the wide-area streamlined structure is increased.

[0056] In addition, the present invention modifies the catalyst and regulates the catalyst composition to make it more suitable for the reaction of asphalt; at the same time, before the reaction, by adding solvent oil, the viscosity of the system and the concentration of aromatic free radicals are reduced, and the selective reaction of the catalyst can be promoted; in addition, while regulating the molecular composition of asphalt, the present invention achieves deep deashing, which meets the requirements for preparing high-end carbon materials.

[0057] The present invention adopts a catalytic coking adsorption purification process to optimize the molecular composition of the raw asphalt, deeply deash the asphalt to below 100 ppm, reduce the mosaic structure of the intermediate phase asphalt obtained from the refined asphalt by 70.59%, reduce the fine fiber structure by 74.63%, increase the wide-area streamlined structure by 362.5%, and make the intermediate phase molecules more orderly.

Claims

1. A method for preparing refined asphalt, characterized in that: The preparation method comprises the following steps: Step (1), impregnating a porous substrate with a loaded metal halide, and drying the obtained impregnated substrate, and calcining under a protective atmosphere to obtain a modified catalyst; wherein the content of the metal halide is 0-10wt% based on the dry basis of the impregnated substrate; and when the content of the metal halide is 0, the modified catalyst is the porous substrate or the calcined porous substrate; Step (2), mixing the asphalt-containing raw material and the solvent oil in a mass ratio of 1:0.1-15 and placing the mixture in a reaction kettle, adding 1-25% by mass of the modified catalyst obtained in step (1), and conducting a catalytic reaction at 320-480° C. for 0.5-5 h to obtain a pretreated product; Step (3), distilling the pre-treated product obtained in step (2) to separate the solvent oil and obtain a residual product; Step (4), mixing the remaining product obtained in step (3) with an extraction solvent to extract the refined asphalt therein, and performing solid-liquid separation, wherein the filtrate is distilled to recover the extraction solvent, and the obtained solid product is the refined asphalt.

2. The preparation method according to claim 1, characterized in that: In step (1), the porous matrix is ​​selected from one or more of zirconia, bentonite, activated carbon, sepiolite, titanium dioxide and diatomaceous earth.

3. The preparation method according to claim 2, characterized in that: In step (1), the selected metal halide is selected from one or more of AlCl3, FeCl3, CuCl2, ZnCl2, MnCl2 and CoCl2.

4. The preparation method according to any one of claims 3, characterized in that In step (1), the content of the metal halide is 0.5-5wt%; and the calcination is carried out at 600-1000°C and in a protective gas atmosphere for 6-20 hours to obtain a modified catalyst.

5. The preparation method according to any one of claims 1 to 4, characterized in that: In step (2), the asphalt-containing raw material is selected from one or more of coal tar pitch, catalytic cracking sedimentation oil, ethylene tar, coal liquefaction pitch and FCC slurry oil; and the solvent oil is one or more of wash oil and anthracene oil.

6. The preparation method according to claim 5, characterized in that: In step (2), the asphalt-containing raw material and solvent oil are mixed uniformly in a mass ratio of 1:0.5-10 and placed in a reactor, and the modified catalyst obtained in step 1 is added in a mass ratio of 1-15%, and reacted at 340-450°C for 0.5-3h to obtain a pretreated product.

7. The preparation method according to any one of claims 1 to 6, characterized in that: In step (3), the pretreated product obtained in step (2) is distilled at 300-400° C. under normal pressure to separate the solvent oil.

8. The preparation method according to any one of claims 1 to 7, characterized in that: In step (4), the extraction solvent is selected from one or more of tetrahydrofuran, pyridine, cyclohexane, toluene and xylene.

9. The preparation method according to claim 8, characterized in that: In step (4), the residual product obtained in step (3) is mixed with an extraction solvent in a mass ratio of 1:5 to 20.

10. The preparation method according to claim 9, characterized in that: In step (4), the filtrate is distilled at 60-200° C. under normal pressure to separate the extraction solvent and obtain refined asphalt.

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