Preparation process of special asphalt raw material

Abstract

The invention discloses a special asphalt raw material preparation process, which comprises: S1, carrying out QI removal treatment according to the QI content in a raw material to obtain an initial material; s2, adjusting material components of the initial material obtained in the step S1 through a gas stripping process or a mixing process to obtain an intermediate product; and S3, filtering the intermediate product to obtain the special asphalt raw material with the softening point of 60-80 DEG C and the QI content of less than or equal to 0.02%. According to the invention, material components are recombined through a gas stripping process or a mixing process, so that uniform distribution of components needing to be excited to react is ensured, reactivity is controllable during subsequent preparation of special asphalt products, and special asphalt raw materials with stable process and low cost are obtained to meet the production requirements of various special asphalt.

Description

Technical Field

[0001] The present invention relates to the technical field of asphalt deep processing, and in particular to a preparation process of special asphalt raw materials. Background Art

[0002] Coal tar accounts for about 55% of coal tar. Asphalt products are mainly divided into three levels according to the degree of deep processing. The most traditional ones are medium-temperature and modified asphalt. After purification, they become purified asphalt and impregnated asphalt. Further deep processing can produce special asphalt. Specifically, according to the different softening points, they can be used for asphalt coating of lithium battery negative electrode materials, asphalt for magnesium carbon bricks, magnesium aluminum carbon bricks, spinning asphalt for general-grade carbon fiber, asphalt for high-performance spherical activated carbon and asphalt for isostatic graphite, etc.

[0003] At present, the raw materials used to prepare special asphalt are all raw materials containing higher quinoline insolubles (QI>3%) such as soft pitch, medium temperature pitch or coal tar. In the production process, these quinoline insolubles can affect the reaction activity, which is unfavorable for oxidative crosslinking and polycondensation. Usually, methods such as filtration, high temperature centrifugation and gravity sedimentation are adopted to control the raw material quinoline insolubles to below 0.3%, but it is difficult to achieve continuous production. Some manufacturers also adopt purified pitch that does not contain QI to prepare special asphalt. For example, a production method of a high softening point coal pitch disclosed in Chinese patent CN102732280B adopts low QI purified coal pitch as raw material. For example, a method for producing carbon fiber with high softening point pitch disclosed in Chinese patent CN102504853B adopts purified pitch that does not contain quinoline insolubles (QI) as raw material. Although the impurity content is few in the asphalt so obtained, the purity is high, but the cost of preparing the raw materials increases because of the need to remove quinoline insolubles.

[0004] In the currently commonly used process, the QI in the raw material is controlled below 0.2% through solvent sedimentation or centrifugation, and then the solvent is recovered to obtain a special asphalt production raw material with QI ≯ 0.15% and a softening point of 60-80°C. However, due to its high softening point, the bottom temperature of the tower needs to be increased to greater than 340°C when recovering the solvent, resulting in the generation of secondary QI. At the same time, some heavier components enter the recovered solvent, affecting its subsequent ability to remove primary QI and reducing the solvent recycling value.

[0005] In view of the shortcomings of existing special asphalt raw materials such as high cost, poor stability and unstable process, it is necessary to develop a process technology for preparing special asphalt raw materials that can produce special asphalt with stable process and low cost. Summary of the Invention

[0006] In response to the defects existing in the prior art, the purpose of the present invention is to provide a preparation process for special asphalt raw materials, which adopts different routes to remove QI according to the content of QI in the raw materials, and reorganizes the material components through a gas stripping process or a mixing process to ensure that the components that need to be stimulated to react are evenly distributed, so that the reactivity can be controlled during the subsequent preparation of special asphalt products, and obtain special asphalt raw materials with stable process and low cost to meet the needs of various special asphalt production.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention provides a process for preparing a special asphalt raw material, comprising the following steps:

[0009] S1, removing QI according to the QI content in the raw material to obtain an initial material;

[0010] S2, the initial material obtained in step S1 is subjected to a stripping process or a mixing process to adjust the material components to obtain an intermediate product;

[0011] S3, filtering the intermediate product to obtain a special asphalt raw material with a softening point of 60-80° C. and a QI content of ≤0.02%.

[0012] Preferably, in step S1:

[0013] When a raw material with a QI of 0.2% < 6% is selected, the QI in the raw material is reduced to ≤ 0.2% by centrifugation, and then 5-10% of the high-activity components are removed through a distillation process to obtain the initial material; or

[0014] When a QI-free raw material is selected, 15-20% of the inert components are removed by distillation to obtain the initial material; or

[0015] When a raw material without QI is selected, it is directly used as the initial material in the mixing process of step S2.

[0016] Preferably, the raw materials with QI of 0.2% < 6% include tar, phenanthrene residual oil and soft asphalt, and the softening point thereof is ≤ 35°C.

[0017] Preferably, the QI-free raw materials include light oil, anthracene oil and heavy oil, and their softening points are ≤30°C.

[0018] Preferably, the centrifugal treatment adopts a stacked centrifuge, the material temperature is 120-150°C, the centrifugal speed is 4000-6000rpm, and the processing capacity is 0.5-2.5m 3 / h.

[0019] Preferably, in the distillation process, the tower top temperature is 160-185° C., the tower bottom temperature is 230-250° C., and the pressure is 20-80 kPaa.

[0020] Preferably, in the step S2, in the stripping process, the material temperature is ≤250°C, and the blowing volume is 0.033-0.16Nm 3 / min, the gas source is air or inert gas or a mixture of the two, and the gas stripping time is 2 to 5 hours.

[0021] Preferably, in the step S2, in the mixing process, the high-reactivity material is added to the initial material under normal pressure, the material temperature is controlled to be ≤250°C, the stirring speed is 100-140 rpm, and the stirring time is 1-3 hours.

[0022] Preferably, in the mixing process, the highly reactive material is selected from one of ethylene tar, C9 resin, coumarone resin and hydrogenated soft asphalt; the highly reactive material does not contain QI and has a softening point of 60 to 125°C.

[0023] Preferably, in step S3, a cartridge filter is used for filtering.

[0024] The beneficial effects of the present invention are:

[0025] 1. The special asphalt raw material produced by the present invention has low production cost, flexible preparation methods, and a wide range of raw material sources. The final product has a high yield of special asphalt, an adjustable softening point, and good melt viscosity. It has a wide range of applications and can be used as asphalt for coating lithium battery negative electrode materials, as asphalt as a binder for magnesium carbon bricks and magnesium aluminum carbon bricks, asphalt for spinning general-grade carbon fiber production, asphalt for high-performance spherical activated carbon, and as a binder for isostatic graphite.

[0026] 2. The present invention readjusts the material components and distributes the group components through air stripping or mixing to ensure that the components that need to be stimulated to react are evenly distributed. When special asphalt products with different softening points are subsequently made, the reactivity can be controlled. At the same time, this process controls the softening point of the intermediate product at 60-80°C to ensure that the material has certain rheological properties and is easy to transport. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0028] Figure 1 Schematic diagram of a process for preparing a special asphalt raw material of the present invention; DETAILED DESCRIPTION

[0029] The present invention will be described in detail below with reference to specific examples. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form.

[0030] The commonly used process currently involves using solvent sedimentation or centrifugation to control the QI in the raw material to below 0.2%, followed by solvent recovery, to produce a specialty asphalt production feedstock with a QI ≤ 0.15% and a softening point of 60-80°C. However, due to the high softening point, solvent recovery requires elevated tower bottom temperatures, typically exceeding 340°C, leading to the formation of secondary QI. Simultaneously, some heavier components enter the recovered solvent, impacting the subsequent removal of primary QI and reducing the solvent's recycling value. To address the high cost, poor stability, and process instability of existing specialty asphalt raw materials, the present invention aims to develop a process technology package for producing specialty asphalt raw materials that is stable and cost-effective.

[0031] Combine Figure 1 As shown, the present invention provides a process for preparing a special asphalt raw material, comprising the following steps:

[0032] S1, removing QI according to the QI content in the raw material to obtain an initial material;

[0033] First, select the raw materials. Depending on the different QI content in the raw materials, different routes can be selected to remove the QI of the raw materials, as follows:

[0034] When selecting raw materials with QI of 0.2% < 4%, such as tar, phenanthrene residual oil and soft asphalt, the softening point is ≤35℃. It is necessary to reduce the QI of the raw materials to ≤0.2% through centrifugation. Then, through the distillation process, 5-10% of the high-activity components that are not conducive to controlling the reaction are removed to obtain the initial material.

[0035] When selecting QI-free raw materials, such as light oil, anthracene oil and heavy oil, whose softening point is ≤30°C, the initial material can be obtained by directly removing 15-20% of the inert components that affect the yield and quality of the final product in a wide component range through the distillation process;

[0036] When raw materials that do not contain QI are selected, such as light oil, anthracene oil and heavy oil, their softening point is ≤30°C and they can be directly used as initial materials in the mixing process of step S2.

[0037] During the above centrifugal treatment, the material temperature is 120-150°C, the centrifugal speed is 4000-6000rpm, and the processing capacity is 0.5-2.5m 3 / h. This centrifugal treatment can use a stacked disc centrifuge to remove primary QI from the raw material. The heat resistance is 160℃, and the shell is equipped with a 120℃ self-limiting insulation to ensure that there is a density difference between the material components, so that the sticky residue coated with QI can be thrown out by the centrifuge;

[0038] In the above-mentioned distillation step, the tower top temperature is 160-185° C., the tower bottom temperature is 230-250° C., and the pressure is 20-80 kPaa (this pressure is absolute pressure).

[0039] S2, the initial material obtained in step S1 is subjected to a stripping process or a mixing process to adjust the material components to obtain an intermediate product;

[0040] The stripping process or mixing process is the core of this process. It can readjust the material components and distribute the group components to ensure that the components that need to be stimulated to react are evenly distributed. When making special asphalt products with different softening points in the future, the reactivity can be controlled. At the same time, this process controls the softening point of the intermediate product at 60-80℃, ensuring that the material has a certain rheological property and is easy to transport.

[0041] The air stripping process is to adjust, distribute and increase the softening point of the material components by using air or inert gas or their mixture at a certain temperature and air injection volume. The control parameters of the air stripping process are as follows: material temperature ≤ 250℃, air injection volume 0.033~0.16Nm 3 / min, the gas source is air or inert gas or a mixture of the two, and the gas stripping time is 2 to 5 hours.

[0042] The mixing process is to add a highly reactive material to the initial material under normal pressure, and readjust, distribute and improve the softening point of the material components under certain temperature and stirring conditions. The control parameters of the mixing process are as follows: material temperature ≤ 250°C, stirring speed 100-140 rpm, stirring time 1-3 hours, and the amount of the highly reactive material added is adjusted according to the required softening point, for example, the amount of the highly reactive material added is 35-64% of the mass of the initial material. The highly reactive material in the endosperm of the mixing process is selected from one of ethylene tar, C9 resin, coumarone resin and hydrogenated soft asphalt, is QI-free, and has a softening point of 60-125°C.

[0043] S3, filtering the intermediate product to obtain a special asphalt raw material with a softening point of 60-80°C and a QI content of ≤0.02%.

[0044] A cartridge filter is used for filtration, and its filter element is composed of 5 layers of filter mesh with a pore size of ≯60 mesh, which are stacked and rolled into a cylindrical shape. One end is sintered and sealed, and then loaded into the filter cartridge. When filtering the intermediate product, the material penetrates the five layers of filter mesh one by one from the bottom of the filter cartridge, enters the center, and leaves the filter cartridge through the upper outlet, finally obtaining a special asphalt raw material with a softening point of 60-80℃, a QI content of ≤0.02%, and no anisotropic components under a microscope.

[0045] The above process can ensure that the components that need to be stimulated to react are evenly distributed, so that when special asphalt products with different softening points are subsequently made, the reactivity can be controlled and the temperature operation flexibility is wide. For example, special asphalt can be prepared at a lower temperature range of 300-340°C to produce products of different quality grades, and the quality and process are controllable.

[0046] The preparation process of the special asphalt raw material of the present invention is further introduced below with reference to specific examples.

[0047] Example 1

[0048] The specific process of preparing the special asphalt raw material of this embodiment is as follows:

[0049] Tar with a softening point of 120°C and a QI content of 3.5% was centrifuged in a stacked centrifuge at a centrifugal speed of 5000 rpm to obtain a concentrate with a QI of 0.15%. It was then distilled to remove unnecessary components and reassemble the components. The distillation conditions were: tower bottom temperature of 250°C, tower top temperature of 180°C, and pressure of 50 kPaa to obtain the initial material. It then entered the air stripping process at a temperature of 230°C and an air blowing volume of 0.033 Nm 3 / min, after stripping for 2 hours, the temperature was raised to 250℃, and filtered through a cartridge filter to obtain special asphalt raw materials. The specific results are shown in the following table:

[0050] QI (%) SP(℃) Heterosexual component (%) Excitation temperature (℃) Special asphalt raw materials 0.01 70 none 330

[0051] Example 2

[0052] The specific process of preparing the special asphalt raw material of this embodiment is as follows:

[0053] Soft asphalt with a softening point of 140°C and a QI content of 6% was centrifuged in a stacked centrifuge at a centrifugal speed of 6000 rpm to obtain a concentrate with a QI of 0.18%. The concentrate was then distilled to remove unnecessary components and reassemble the components. The distillation conditions were: a tower bottom temperature of 230°C, a tower top temperature of 160°C, and a pressure of 80 kPaa to obtain an initial material. The initial material was then mixed in a mixing process, where 35% by mass of hydrogenated asphalt with a softening point of 105°C was added to the initial material. The mixture was mixed at a temperature of 250°C and a stirring speed of 140 rpm for 3 hours, then the temperature was raised to 250°C and filtered through a cartridge filter to obtain a special asphalt raw material. The specific results are as follows:

[0054] QI (%) SP(℃) Heterosexual component (%) Excitation temperature (℃) Special asphalt raw materials 0.02 80 none 320

[0055] Example 3

[0056] The specific process of preparing the special asphalt raw material of this embodiment is as follows:

[0057] The heavy oil without QI and with a softening point of 10°C was distilled to remove unnecessary components and reassemble the components. The distillation conditions were: bottom temperature of 230°C, top temperature of 180°C, and pressure of 60kPaa to obtain the initial material. Then, the gas stripping process was carried out at a temperature of 250°C and a nitrogen blowing volume of 0.16Nm 3 / min, after stripping for 3 hours, the temperature was raised to 250℃, and filtered through a barrel filter to obtain special asphalt raw materials. The specific results are as follows:

[0058] QI (%) SP(℃) Heterosexual component (%) Excitation temperature (℃) Special asphalt raw materials 0.008 65 none 310

[0059] Example 4

[0060] The specific process of preparing the special asphalt raw material of this embodiment is as follows:

[0061] Anthracene oil without QI and with a softening point of 12-20°C was mixed with C9 resin (softening point 84°C) in a mass ratio of 4:6 at a temperature of 220°C and a stirring speed of 120 rpm. The material components were redistributed and blended for 5 hours, then the temperature was raised to 250°C and filtered through a cartridge filter to obtain a special asphalt raw material. The specific results are as follows:

[0062] QI (%) SP(℃) Heterosexual component (%) Excitation temperature (℃) Special asphalt raw materials 0 60 none 305

[0063] Example 5

[0064] The specific process of preparing the special asphalt raw material of this embodiment is as follows:

[0065] The heavy oil without QI and with a softening point of 6-10℃ and coumarone resin (softening point 73℃) were mixed in a mass ratio of 10:3, and the mixture (air: nitrogen = 10:7wt%) was blown at a temperature of 250℃ and a blowing volume of 0.05Nm 3 / min, the components were blended for 1.5 hours, then the temperature was raised to 250°C and filtered through a barrel filter to obtain a special asphalt raw material. The specific results are as follows:

[0066] QI (%) SP(℃) Heterosexual component (%) Excitation temperature (℃) Special asphalt raw materials 0 70 none 340

[0067] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, and all of these should be included in the scope of the claims of the present invention.

Claims

1. A process for preparing special asphalt raw materials, characterized in that: The following steps are involved: S1, removing QI according to the QI content in the raw material to obtain an initial material; S2, the initial material obtained in step S1 is subjected to a stripping process or a mixing process to adjust the material components to obtain an intermediate product; S3, filtering the intermediate product to obtain a special asphalt raw material with a softening point of 60-80° C. and a QI content of ≤0.02%.

2. The method for preparing the special asphalt raw material according to claim 1, wherein: In the step S1: When a raw material with a QI of 0.2% < 6% is selected, the QI in the raw material is reduced to ≤ 0.2% by centrifugation, and then 5-10% of the high-activity components are removed through a distillation process to obtain the initial material; or When a QI-free raw material is selected, 15-20% of the inert components are removed by distillation to obtain the initial material; or When a raw material without QI is selected, it is directly used as the initial material in the mixing process of step S2.

3. The preparation method of the special asphalt raw material preparation process according to claim 2, characterized in that: The raw materials with a QI of 0.2% < 6% include tar, phenanthrene residual oil and soft asphalt, and the softening point thereof is ≤ 35°C.

4. The preparation method of the special asphalt raw material preparation process according to claim 2, characterized in that: The raw materials free of QI include light oil, anthracene oil and heavy oil, and the softening point thereof is ≤30°C.

5. The preparation method of the special asphalt raw material preparation process according to claim 2, characterized in that: The centrifugal treatment adopts a stacked centrifuge, the material temperature is 120-150°C, the centrifugal speed is 4000-6000rpm, and the processing capacity is 0.5-2.5m 3 / h.

6. The method for preparing the special asphalt raw material according to claim 2, wherein: In the distillation process, the tower top temperature is 160-185° C., the tower bottom temperature is 230-250° C., and the pressure is 20-80 kPaa.

7. The method for preparing the special asphalt raw material according to claim 1, wherein: In the step S2, during the gas stripping process, the material temperature is ≤250°C, and the blowing volume is 0.033-0.16 Nm 3 / min, the gas source is air or inert gas or a mixture of the two, and the gas stripping time is 2 to 5 hours.

8. The method for preparing the special asphalt raw material according to claim 1, wherein: In the step S2, in the mixing process, the high-reactivity material is added to the initial material under normal pressure, the material temperature is controlled to be ≤250°C, the stirring speed is 100-140 rpm, and the stirring time is 1-3 hours.

9. The method for preparing the special asphalt raw material according to claim 8, wherein: In the mixing process, the highly reactive material is selected from one of ethylene tar, C9 resin, coumarone resin and hydrogenated soft asphalt; the highly reactive material does not contain QI and has a softening point of 60 to 125°C.

10. The method for preparing the special asphalt raw material according to claim 1, wherein: In the step S3, a cartridge filter is used for filtering.

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