Mesophase pitch raw material and refining process thereof

Abstract

The invention discloses a mesophase pitch raw material and a refining process thereof, and the refining process comprises the following steps: mixing the mesophase pitch raw material with solvent oil, heating and stirring to obtain a mixed liquid; introducing inert gas into the mixed liquid, heating, and carrying out pressurized hot filtration to obtain filtrate; carrying out reduced pressure distillation on the filtrate to obtain a refined mesophase pitch raw material; wherein the mass ratio of the mesophase pitch raw material to the solvent oil is 1: (0.8-5). According to the prepared mesophase pitch raw material, the content of native quinoline insoluble substances is smaller than 0.02%, the ash content is smaller than 30 ppm, and the content of mechanical impurities is smaller than 0.06%.

Description

Technical Field

[0001] The present application relates to the field of asphalt technology, and in particular to a mesophase asphalt raw material and a refining process thereof. Background Art

[0002] Asphalt, as a raw material for carbon-based materials, has the advantages of high carbon content and low cost, and has received extensive attention in the preparation of various carbonaceous materials. At present, asphalt is widely used in industry and can be used as a raw material for producing high-value-added products such as impregnating agent asphalt, needle coke, mesophase asphalt, carbon fiber, etc., but the quality requirements of asphalt are extremely high. First of all, the native quinoline insoluble matter (PQI) in asphalt will seriously affect the performance of the product. On the one hand, it is not conducive to the transformation of the mesophase. Too high a content will hinder the fusion of the mesophase spheres and easily generate a mosaic structure during the carbonization process; on the other hand, PQI also has certain active centers, which can reduce the activation energy of the mesophase transformation and promote the nucleation of the mesophase. Therefore, the raw asphalt needs to be purified to remove PQI, and the PQI in the raw asphalt is generally required to be less than 0.1%. In addition, there are some ash and mechanical impurities in the raw asphalt, which may affect the physical properties of the mesophase asphalt, such as viscosity and softening point. Therefore, it is necessary to remove them in the refining process of the raw asphalt, so that the content of impurities such as PQI and ash is as low as possible.

[0003] At present, the methods for removing PQI in industry mainly focus on hydrogenation chemical modification, solvent extraction sedimentation and centrifugal separation. However, the above methods have the problems of complex process, high energy consumption, large solvent consumption and high equipment cost. Summary of the invention

[0004] In order to solve the above-mentioned deficiencies in the art, the present application aims to provide a mesophase asphalt raw material and a refining process thereof to remove native quinoline insolubles (PQI), ash and mechanical impurities in the asphalt raw material.

[0005] According to one aspect of the present application, a refining process for mesophase asphalt raw material is provided, comprising:

[0006] The mesophase asphalt raw material is mixed with solvent oil, heated and stirred to obtain a mixed liquid;

[0007] Inert gas is introduced into the mixed liquid and heated, and pressure hot filtration is performed to obtain a filtrate;

[0008] The filtrate is subjected to vacuum distillation to obtain a refined mesophase asphalt raw material;

[0009] Wherein, the mass ratio of mesophase asphalt raw material to solvent oil is 1:(0.8-5);

[0010] The filter layer is a double-layer filter system.

[0011] According to some embodiments of the present application, the double-layer filtration system consists of a 2-5 cm 30-500 mesh diatomaceous earth layer and a 500-2000 mesh stainless steel filter layer.

[0012] According to some embodiments of the present application, the mesophase asphalt raw materials include: petroleum asphalt, coal asphalt, and naphthalene asphalt.

[0013] According to some embodiments of the present application, the solvent oil includes: phenol oil, naphthalene oil, kerosene, washing oil, and anthracene oil.

[0014] According to some embodiments of the present application, the pressurized hot filtration is pressurized to 0.1-2.5 MPa and heated to 100-220°C.

[0015] According to some embodiments of the present application, the filter layer materials used in pressurized hot filtration include: 30-500 mesh diatomaceous earth, 30-500 mesh kaolin, sintered ceramics with a pore size of 1-10 μm, 500-2000 mesh stainless steel filter screen, and quantitative filter paper.

[0016] According to some embodiments of the present application, the thickness of the filter layer material is 3-8 cm.

[0017] According to some embodiments of the present application, the temperature of heating and stirring is 100-200° C., and the stirring time is 30-300 min.

[0018] According to some embodiments of the present application, the vacuum degree of the reduced pressure distillation is 0.05-0.1 MPa, and the temperature is 120-300°C.

[0019] According to another aspect of the present application, there is also provided a mesophase asphalt raw material prepared by the above refining process, wherein the native quinoline insoluble matter is less than 0.02%, the ash content is less than 30 ppm, and the mechanical impurities are less than 0.06%.

[0020] Compared with the prior art, this application has at least the following beneficial effects:

[0021] The present application provides a refining process for mesophase asphalt raw materials. The method and process are simple, economical and environmentally friendly, suitable for industrial continuous refined asphalt, and also suitable for the refining of raw materials for high value-added products such as impregnating agent asphalt, needle coke, carbon fiber, etc.

[0022] The mesophase asphalt raw material prepared by the refining process of the present application has a PQI of less than 0.02%, an ash content of less than 30ppm, and a mechanical impurity content of less than 0.06%. At the same time, the mesophase asphalt raw material using the refining process of the present application can obtain a wide-area streamlined mesophase asphalt with a mesophase content of more than 99.6% after polycondensation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1A schematic diagram of an apparatus for a refining process according to an exemplary embodiment of the present application.

[0024] Figure 2 These are the performance test data of the refined asphalt raw material obtained by the refining process in the exemplary embodiment of this application.

[0025] Figure 3 This is a polarizing microscope image of the mesophase pitch obtained after thermal polycondensation in an exemplary embodiment of the present application.

[0026] in, Figure 1 1 and 2 are raw material tanks, 3 and 4 are metering pumps, 5 is a heating pipe, 6 is an inlet / outlet valve, 7 is a reactor, 8 is a heating jacket for the reactor, 9 and 10 are metering pumps, 11 and 12 are hot filtration devices, 13 is a filter residue discharge port, 14 is a filter layer, 15 is a distillation tower, 16 is a refined asphalt discharge port, 17 is a condenser, 18 and 19 are collecting tanks, 20 is a vacuum pump, and 21 is a circulating pump. DETAILED DESCRIPTION

[0027] The technical solution of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0028] It is particularly important to point out that similar substitutions and modifications made to the present application are obvious to those skilled in the art, and they are all deemed to be included in the present application. Relevant personnel can obviously modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit and scope of the present application to implement and apply the technology of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments.

[0029] If no specific conditions are specified in this application, the preparation shall be carried out under conventional conditions or the conditions recommended by the manufacturer. The raw materials or excipients used, as well as the reagents or instruments used, for which the manufacturers are not specified, are all conventional products that can be obtained commercially.

[0030] The application is described in detail below.

[0031] In view of the pain points in the process of purifying raw material asphalt in the existing industrial production of mesophase asphalt, the present application provides a refining process for industrial production of mesophase asphalt raw materials. With petroleum asphalt, coal tar or naphthalene asphalt as raw materials, after the heating and dissolution of solvent oils such as phenol oil, naphthalene oil, kerosene, wash oil or anthracene oil, the mixed solution is pumped out by a pump and enters the hot filtration kettle. Under the protection of inert gas, the mixed solution is pressurized and filtered on the filter layer material to remove native quinoline insolubles (PQI), ash and mechanical impurities. The filtered mixed solution is pumped into a vacuum distillation tower, and the solvent oil is decompressed and evaporated back into the raw material tank for recycling, and the refined asphalt is separated after cooling at the bottom of the tower.

[0032] The refining process of the mesophase asphalt raw material of the present application comprises:

[0033] 1) Add the raw materials and solvent oil into the reactor in a mass ratio of 1:0.8-5, stir mechanically and heat until uniform;

[0034] 2) The mixed solution in step 1) is pumped out by a pump and transported to a hot filtration kettle; and hot filtration is performed through the filter material laid in advance;

[0035] 3) Inject inert gas through the air inlet valve, and perform pressurized hot filtration of the mixed solution under a protective atmosphere;

[0036] 4) The obtained filtrate is transported to a vacuum distillation tower through a pump. Under the action of vacuum distillation, the solvent oil is recovered to the reactor for recycling, and the target refined asphalt is obtained after cooling the bottom of the tower.

[0037] Among them, the raw materials are petroleum asphalt, coal asphalt, naphthalene asphalt or other synthetic chemical raw materials.

[0038] Solvent oils include common oils such as phenol oil, naphthalene oil, kerosene, washing oil or anthracene oil.

[0039] The filter layer material is 30-500 mesh diatomaceous earth, 30-500 mesh kaolin, sintered ceramic with a pore size of 1-10 microns, or 500-2000 mesh stainless steel filter mesh or quantitative filter paper, and the filter layer thickness is 3-8 cm; further, the filter material is a double-layer filtration system consisting of a 30-500 mesh diatomaceous earth filter layer 2-5 cm high and a 500-2000 mesh stainless steel filter mesh.

[0040] The temperature for mechanical stirring and heating is 100-200°C, and stirring is carried out for 30-300 minutes until the solution is uniform.

[0041] Inert gas is introduced and pressurized to 0.1-2.5MPa, and heated to 100-220°C; the inert gas is high-purity nitrogen or argon.

[0042] The conditions for reduced pressure distillation are a vacuum degree of 0.05-0.1 MPa and a temperature of 120-300°C.

[0043] like Figure 1 As shown, the refining device used in the exemplary embodiment of the present application, wherein the raw material tanks 1 and 2 are transported to the reactor 7 under the action of the heating pipe 5, and then connected to the hot filtering devices 11 and 12 through the pipe, and finally connected to the distillation tower 15 through the pipe. Among them: raw material tank 1 is a storage tank for solvent oil; raw material tank 2 is a storage tank for raw asphalt, and the outer side of the tank is provided with a heating jacket to melt the asphalt into liquid state; metering pumps 3 and 4 can transport the solvent and raw asphalt to the reactor 7 according to the set feed ratio; the reactor 7 is a vertical empty reactor with a stirring paddle and a heating jacket; metering pumps 9 and 10 can transport the mixed solution to the hot filter devices 11 and 12 in parallel; the hot filter devices 11 and 12 are provided with an inert gas inlet and outlet at the top and a filter residue outlet at the bottom; the filter layer 14 is composed of solid filter material and a stainless steel mesh; the distillation tower 15 is a packed tower, and the internal filling filler can be one of Raschig rings, rectangular saddle fillers, ball rings, Nath rings or step rings made of ceramic or metal materials, and there is an electric heating device at the bottom, and the reflux ratio is 2-10. The solvent decompressed at the top of the distillation tower 15 is recovered into the collection tank through the condenser 17, and the refined asphalt is cut out at the bottom of the tower. Under the action of the circulation pump 21, the distilled solvent is continuously transported to the raw material tank 1 for recycling.

[0044] In combination with the above-mentioned refining device, the refining process of the present application includes:

[0045] 1) After the raw asphalt in the raw material tank 2 is heated to 60-120°C, it is transported to the reactor 7 by the metering pumps 3 and 4 at a mass ratio of 1:0.8-5; at an ambient temperature of 100-200°C in the reactor, it is mechanically stirred for 30-300 minutes until the solution is uniform, and then enters the hot filtration stage;

[0046] 2) The mixed solution in step 1) is delivered to the hot filtration device by metering pumps 9 and 10. When the injection amount of the mixed solution reaches 2 / 3 of the maximum capacity of the hot filtration, the feeding is stopped;

[0047] 3) The filter layer is composed of diatomaceous earth, kaolin or sintered ceramics laid flat on a stainless steel filter screen or filter paper.

[0048] 4) The inert gas enters the hot filtration device through the air inlet valve 6, and the mixed solution is filtered under a pressure of 0.1-2.5 MPa and a temperature of 100-220° C. The filter residue is discharged from the filter residue discharge port 13;

[0049] 5) The filtrate is pumped to a distillation tower for vacuum distillation. The solvent oil is recovered to collection tanks 18 and 19 through a condenser 17, and the recovered solvent is transported to the raw material tank 1 again by a circulation pump 21. The refined asphalt is separated after cooling at the bottom of the distillation tower.

[0050] The technical solution of the present application is further described below in conjunction with specific embodiments.

[0051] Example 1

[0052] The heated raw coal tar and solvent oil phenol oil are transported to the reactor by a metering pump at a mass ratio of 1:1.5. After mechanical stirring, the mixed liquid is pumped to the hot filtration device for pressurized hot filtration. The filter layer material is composed of 300 mesh diatomaceous earth and 1000 mesh stainless steel mesh, and the filter layer thickness is 3 cm. The hot filtration is carried out under the protection of N2, pressurized to 0.4MPa, and at a temperature of 100℃. After hot filtration, the filtrate is pumped to the distillation tower for vacuum distillation to separate the solvent oil, and the refined asphalt is separated by cooling at the bottom of the tower to obtain refined asphalt.

[0053] The parameters of Examples 1-10 are detailed in the table below:

[0054]

[0055]

[0056] The refined asphalt of the comparative example was prepared according to the method of Example 1, and the parameters are shown in the following table:

[0057]

[0058] Experimental Example Testing the Impurity Content in the Examples and Comparative Examples

[0059]

[0060]

[0061] According to the data in the table above, the PQI of the raw asphalt refined by the method of the present application is less than 0.02%, the ash content is less than 30ppm, and the mechanical impurities are less than 0.06%. However, in Comparative Example 1, the amount of solvent oil added is small, the thickness of the filter layer in Comparative Example 2 is too thin, Comparative Examples 3 and 4 are single-layer filtration, and the filter layer of Comparative Example 5 is thin, all of which show poor refining effects. In Comparative Example 6, the filtration pressure and temperature are increased, but it is found that the improvement in the refining effect is not obvious. Figure 1 A purification device used in the preparation of refined asphalt according to the present invention;

[0062] Figure 2 The performance parameters of PQI, mechanical impurities and softening point of the raw asphalt obtained by the refining method of the present invention; Figure 3 The polarizing microscope image of the mesophase asphalt obtained by the refined asphalt obtained by the present invention through a one-step thermal polycondensation method shows that the refined asphalt prepared by the present method has the use of being a precursor raw material of the mesophase asphalt.

[0063] The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. It should be noted that, for ordinary technicians in this technical field, several improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A process for refining mesophase asphalt raw materials, characterized in that: include: The mesophase asphalt raw material is mixed with solvent oil, heated and stirred to obtain a mixed liquid; Introducing an inert gas into the mixed liquid and heating it, and performing pressurized hot filtration to obtain a filtrate; The filtrate is subjected to reduced pressure distillation to obtain a refined mesophase asphalt raw material; Wherein, the mass ratio of the mesophase asphalt raw material to the solvent oil is 1:(0.8-5); The filter layer of the pressurized hot filtration is a double-layer filter system.

2. The refining process according to claim 1, characterized in that: The mesophase asphalt raw materials include: petroleum asphalt, coal asphalt, and naphthalene asphalt.

3. The refining process according to claim 1, characterized in that: The solvent oil includes: phenol oil, naphthalene oil, kerosene, washing oil and anthracene oil.

4. The refining process according to claim 1, characterized in that: The pressurized hot filtration is pressurized to 0.1-2.5 MPa and heated to 100-220°C.

5. The refining process according to claim 4, characterized in that: The materials of the filter layer include: 30-500 mesh diatomaceous earth, 30-500 mesh kaolin, sintered ceramics with a pore size of 1-10 μm, 500-2000 mesh stainless steel filter screen, and quantitative filter paper.

6. The refining process according to claim 5, characterized in that: The thickness of the filter layer is 3-8 cm.

7. The refining process according to claim 6, characterized in that: The double-layer filtration system consists of a 2-5 cm 30-500 mesh diatomaceous earth layer and a 500-2000 mesh stainless steel filter layer.

8. The refining process according to claim 1, characterized in that: The heating and stirring temperature is 100-200° C., and the stirring time is 30-300 min.

9. The refining process according to claim 1, characterized in that: The vacuum degree of the reduced pressure distillation is 0.05-0.1 MPa, and the temperature is 120-300°C.

10. A mesophase asphalt raw material prepared by the refining process according to any one of claims 1 to 9, characterized in that: The insoluble matter of native quinoline is less than 0.02%, the ash content is less than 30ppm, and the mechanical impurities are less than 0.06%.

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