A preparation method for improving quality of modified asphalt by using tar residue

Abstract

The application discloses a preparation method for improving the quality of modified asphalt by using tar residue, relates to the technical field of asphalt preparation, and comprises a raw material tank, a tar residue bin, a coarse grinding machine, a first ultracentrifuge, an ammonia water underground tank, a coal tar storage tank, a plurality of second liquefied tanks, a fine grinding machine and a second ultracentrifuge. Two tar residue self-unloading centrifuges are connected to the discharge port of the raw material tank. The discharge outlets of the two tar residue self-unloading centrifuges are connected with the feed inlet of the tar residue bin. The discharge outlets of the two tar residue self-unloading centrifuges are connected with buffer bins. The method has the advantages of mild reaction conditions, low equipment requirements, low operation energy consumption, small safety risks, effective regulation and control of the polymerization degree of asphalt, and accurate improvement of the coking value and bonding performance of modified asphalt. The quality of the whole process from the raw material tar residue obtained from the inside of the raw material tank to the storage of the modified asphalt in the coal tar storage tank is closed-loop controlled, so that the stable production of high-quality modified asphalt is ensured.

Description

Technical Field

[0001] This invention relates to the field of asphalt preparation technology, specifically a method for improving the quality of modified asphalt using tar residue. Background Technology

[0002] Coal tar is an important product recovered through condensation during coal gasification, accounting for approximately 3-4% of the yield of coking coal. Coal tar has an extremely complex composition, containing tens of thousands of substances, among which naphthalene oil, anthracene oil, wash oil, and phenols are unique and scarce chemical raw materials found in coal tar.

[0003] Modified pitch, a product of coal tar processing, is a major byproduct of tar production, accounting for over 50% of total tar output. It is primarily used in the manufacture of prebaked anodes for the electrolytic aluminum industry and in the preparation of high-value-added carbon materials such as battery rods and electrode binders. However, due to the quality of the raw material tar, modified pitch suffers from problems such as low quinoline insolubles, low toluene insolubles, high volatile matter, and low coking value. This results in carbon products with defects such as high resistivity, poor oxidation and thermal stability, and low mechanical strength.

[0004] Currently, the main production process for modified asphalt employs thermal polycondensation, including autoclave heating and tubular furnace heating. Among these, tubular furnace heating systems for modified asphalt production include the pressurized double-furnace double-autoclave process imported from France, the domestic atmospheric or reduced-pressure double-autoclave single-furnace process, and the single-furnace single-autoclave process. These processes share some common problems, such as high reaction temperatures, coking and deformation of the reaction vessel, complex production processes, high operating costs, and large energy consumption and emissions.

[0005] For example, an existing patent document (authorization announcement number CN103205272B) discloses a method for producing purified coal tar pitch from high-temperature coal tar, comprising: mixing high-temperature coal tar with hydrogenated heavy solvent and deionized water to remove salts, thereby obtaining desalted high-temperature coal tar; mixing the desalted high-temperature coal tar with an aliphatic solvent to remove quinoline insolubles, thereby obtaining clarified oil; distilling the clarified oil to obtain a mixture of aliphatic solvent, phenol oil, naphthalene oil, purified coal tar pitch, light oil, wash oil, anthracene oil, and hydrogenated heavy solvent, wherein the mixture is used as catalytic hydrogenation feed oil; catalytically hydrogenating the catalytic hydrogenation feed oil to obtain hydrogenated refined oil; and distilling the hydrogenated refined oil to obtain naphtha components, gasoline blending components, diesel blending components, and hydrogenated heavy solvent.

[0006] Taking the above-mentioned method for producing purified coal tar pitch as an example, in actual operation, unmodified coal tar pitch has problems such as low softening point, high volatile matter, and low coking value, resulting in defects such as high resistivity, poor oxidation resistance and thermal stability, and low mechanical strength in the produced electrode products. The production process requires high-temperature reaction, which easily leads to problems such as coking in the reaction vessel, increased concentration of transported liquid causing pipeline blockage, complex temperature control process for production safety, and high cost of high-temperature waste gas treatment. Summary of the Invention

[0007] The purpose of this invention is to provide a method for improving the quality of modified asphalt using tar residue, in order to solve the problems proposed in the prior art, such as the need for high-temperature reaction in the production process, easy coking in the reaction vessel, increased liquid concentration leading to pipeline blockage, complex temperature control process for production safety, and high cost of high-temperature waste gas treatment.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing modified asphalt using tar residue to improve its quality, comprising a raw material tank, a tar residue silo, a coarse grinding mill, a first ultracentrifuge, an underground ammonia tank, a coal tar storage tank, multiple second liquefaction tanks, a fine grinding mill, and a second ultracentrifuge. The outlet of the raw material tank is connected to two self-unloading tar residue centrifuges. The drain outlets of both self-unloading tar residue centrifuges are connected to the inlet of the tar residue silo. The outlets of both self-unloading tar residue centrifuges are connected to buffer silos. The outlets of the two buffer silos are... All are connected to the feed inlet of the coarse grinding mill, the discharge outlet of the coarse grinding mill is connected to the feed inlet of the fine grinding mill, the discharge outlet of the fine grinding mill is connected to the feed inlet of the first ultracentrifuge, the discharge outlet of the first ultracentrifuge is connected to the feed inlet of the second ultracentrifuge, the discharge outlet of the second ultracentrifuge is connected to the feed inlets of the two first liquefaction tanks, the drain outlets of the two first liquefaction tanks are all connected to tar extraction pumps, the discharge outlets of the two tar extraction pumps are all fixedly connected to the feed inlet of the coal tar storage tank, and the discharge outlets of the two first liquefaction tanks are all connected to the feed inlet of the rightmost second liquefaction tank.

[0009] Preferably, the two adjacent second liquefaction tanks are arranged in such an installation pattern that the discharge port of the right second liquefaction tank is connected to the inlet of the left second liquefaction tank, and the ammonia underground tank is connected to the discharge port of the leftmost second liquefaction tank.

[0010] Preferably, in step one: the raw material tank is insulated with a jacket and equipped with an agitator inside to prevent tar residue from settling, condensing or agglomerating; the temperature inside the raw material tank is maintained at ℃ using steam heating, and the two first liquefaction tanks are preheated to ℃ inside.

[0011] Preferably, in step two: two self-unloading centrifuges extract the tar residue and separate the solid residue from the tar residue; the discharge port of the self-unloading centrifuges transports the processed tar residue to the inlet of the connected buffer silo, where the tar residue is left to stand, causing it to separate into layers, and a decanter is installed inside the buffer silo to drain the upper layer of water.

[0012] Preferably, in step three: the coarse grinding mill extracts tar residue from the two buffer hoppers for coarse grinding and crushing. After crushing, the tar residue is conveyed to the fine grinding mill for fine grinding and crushing. After crushing, the tar residue is conveyed to the first ultracentrifuge. The first ultracentrifuge performs preliminary filtration on the crushed tar residue. After filtration by the first ultracentrifuge, the tar residue is conveyed to the second ultracentrifuge for further filtration.

[0013] Preferably, in step four: the tar residue purified by the second ultracentrifuge is diverted into the two first liquefaction tanks. The first liquefaction tanks use a gradient steam heat exchanger to control the temperature. The temperature is finely adjusted in real time according to the moisture content and viscosity of the tar residue. The temperature is appropriately increased for materials with high viscosity and high moisture content. The self-produced wash oil of the unit is selected as a special diluent. The amount of diluent added is controlled by the dynamic ratio control technology of modified coal tar QI index.

[0014] Preferably, in step five: during the heating process of the tar residue, the heavy asphalt component remains at the bottom of the inner cavity of the first liquefaction tank, and the tar extraction pump works to extract the asphalt from the bottom of the inner cavity of the first liquefaction tank and transport it to the inside of the coal tar storage tank for storage.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This application utilizes a precise thermal condensation reaction at 70℃ under normal pressure for 3 hours to prepare modified asphalt. Compared to traditional high-temperature, high-pressure, and long-duration polymerization processes, this method offers milder reaction conditions, lower equipment requirements, lower energy consumption, and lower safety risks. It also effectively controls the degree of asphalt polymerization, precisely improving the coking value and bonding performance of the modified asphalt. A closed-loop quality control system is implemented throughout the entire polymerization process, from obtaining raw material tar residue from the raw material tank to storing the modified asphalt in the coal tar storage tank. This ensures a high-quality and stable output of modified asphalt. Strict closed-loop control is applied to core indicators such as softening point, coking value, quinoline insolubles, toluene insolubles, and ash content, ensuring that the finished modified asphalt fully meets the standards used in the carbon and electrolytic aluminum industries, achieving high-value and resource-based utilization of tar residue.

[0016] 2. In this application, the first liquefaction tank adopts a gradient steam heat exchange temperature control of 65-72℃. The temperature is finely adjusted in real time according to the moisture content and viscosity of the tar residue. The temperature is appropriately increased for high-viscosity, high-moisture materials, while low-viscosity materials are kept at a low constant temperature. This flexibly adapts to tar residue in different states, avoiding the problems of insufficient material flowability or loss of light components due to a single temperature. The self-produced wash oil of the unit is selected as a special diluent. The agitator inside the first liquefaction tank mixes the diluent with the ground and purified tar residue to homogenize and dilute the tar residue. The dynamic QI index of modified coal tar is used. The dynamic ratio control technology regulates the amount of diluent added, which reduces the viscosity of tar residue, ensures smooth pipeline transportation, and avoids the introduction of foreign impurities. It maximizes the retention of effective components in tar residue, balances environmental protection and material stability, and achieves efficient resource utilization of waste residue. It abandons the traditional fixed ratio blending method and dynamically adjusts the mixing mass ratio of tar residue and coal tar according to the real-time content of quinoline insoluble matter (QI) in the raw coal tar. It can be adapted to raw coal tar of different origins and qualities, significantly improves the stability of modified asphalt product indicators, and solves the problem of product quality failure caused by raw material fluctuations.

[0017] 3. In this application, the coarse grinding mill draws tar residue from two buffer silos for coarse grinding and crushing. After crushing, the tar residue is conveyed to the fine grinding mill for fine grinding and crushing. After crushing, the tar residue is conveyed to the first ultracentrifuge. The first ultracentrifuge performs preliminary separation on the crushed tar residue. After filtration by the first ultracentrifuge, the tar residue is conveyed to the second ultracentrifuge for further separation, ensuring that solid impurities are separated. The traditional single-stage grinding + pure washing oil dilution process is eliminated. A two-stage grinding + precision filtration + dilution solvent is adopted. First, the material is refined through coarse grinding and fine grinding to remove large particulate impurities. Then, the solid phase impurities are filtered by centrifugation equipment. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the present invention.

[0019] Labels in the diagram: 1. Raw material tank; 2. Tar residue bin; 3. Tar residue self-unloading centrifuge; 4. Buffer bin; 5. Coarse grinder; 6. First liquefaction tank; 7. First ultracentrifuge; 8. Ammonia water underground tank; 9. Coal tar storage tank; 10. Tar extraction pump; 11. Second liquefaction tank; 12. Fine grinder; 13. Second ultracentrifuge. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example: Figure 1 As shown, this invention provides a method for preparing modified asphalt using tar residue to improve its quality. The method includes a raw material tank 1, a tar residue silo 2, a coarse grinder 5, a first ultracentrifuge 7, an underground ammonia tank 8, a coal tar storage tank 9, multiple second liquefaction tanks 11, a fine grinder 12, and a second ultracentrifuge 13. The raw material tank 1 is connected to two tar residue self-unloading centrifuges 3 via their discharge ports. The discharge ports of both tar residue self-unloading centrifuges 3 are connected to the inlets of the tar residue silo 2. The discharge ports of both tar residue self-unloading centrifuges 3 are connected to buffer silos 4. The discharge ports of both buffer silos 4 are connected to the inlets of the coarse grinder 5. The discharge port of the coarse grinder 5 is connected to the inlet of the fine grinder 12. The feed inlet is connected as follows: the discharge port of the fine grinding mill 12 is connected to the feed inlet of the first ultracentrifuge 7; the discharge port of the first ultracentrifuge 7 is connected to the feed inlet of the second ultracentrifuge 13; the discharge port of the second ultracentrifuge 13 is connected to the feed inlets of the two first liquefaction tanks 6; the drain outlets of the two first liquefaction tanks 6 are each connected to a tar extraction pump 10; the discharge outlets of the two tar extraction pumps 10 are each fixedly connected to the feed inlet of the coal tar storage tank 9; the discharge outlets of the two first liquefaction tanks 6 are each connected to the feed inlet of the rightmost second liquefaction tank 11; and the discharge outlet of the rightmost second liquefaction tank 11 is connected to the feed inlet of the leftmost second liquefaction tank 11; the ammonia water underground tank 8 is connected to the discharge outlet of the leftmost second liquefaction tank 11. In summary, the modified asphalt preparation system comprises the following components: raw material tank 1, tar residue silo 2, underground ammonia water tank 8, coal tar storage tank 9, multiple secondary liquefaction tanks 11, two tar residue self-unloading centrifuges 3, two buffer silos 4, coarse grinder 5, two primary liquefaction tanks 6, primary ultracentrifuge 7, two tar extraction pumps 10, multiple secondary liquefaction tanks 11, fine grinder 12, and secondary ultracentrifuge 13. The specific operating method of the modified asphalt preparation system is as follows: Step 1: Control the operation of raw material tank 1, two tar residue self-unloading centrifuges 3, two first liquefaction tanks 6 and multiple second liquefaction tanks 11. Raw material tank 1 is jacketed and insulated and equipped with an internal stirrer with a speed of 200-300 rpm to prevent tar residue from settling, condensing or agglomerating. The temperature inside raw material tank 1 is maintained at 68℃ by steam heating. The two first liquefaction tanks 6 are preheated to 70℃. Step 2: Two self-unloading centrifuges 3 extract the tar residue and separate the solid residue from it. The discharge port of the self-unloading centrifuges 3 discharges the solid residue into the feed port of the connected tar residue bin 2. The discharge port of the self-unloading centrifuges 3 transports the processed tar residue to the feed port of the connected buffer bin 4. The tar residue is left to stand in the buffer bin 4 to allow it to separate into layers. A decanter is installed inside the buffer bin 4 to drain the upper layer of water, further reducing the moisture content of the tar residue and avoiding the problem of excessive moisture affecting the subsequent thermal condensation reaction and the coking value of the finished asphalt. Step 3: The coarse grinding mill 5 draws tar residue from the two buffer silos 4 for coarse grinding. After coarse grinding, the tar residue is conveyed to the fine grinding mill 12 for fine grinding. After fine grinding, the tar residue is conveyed to the first ultracentrifuge 7 for initial separation. After filtration, the tar residue is conveyed to the second ultracentrifuge 13 for further separation, ensuring that solid impurities are separated. The traditional single-stage grinding + pure washing oil dilution process is eliminated. A two-stage grinding + precision filtration + dilution solvent is adopted. First, the material is refined through coarse grinding and fine grinding to remove large particle impurities. Then, the solid phase impurities are filtered by centrifugation equipment. Step 4: After purification by the second ultracentrifuge 13, the tar residue is diverted into the two first liquefaction tanks 6. The first liquefaction tanks 6 use a gradient steam heat exchanger with a temperature of 65-72℃. The temperature is finely adjusted in real time according to the moisture content and viscosity of the tar residue. The temperature is appropriately increased for high-viscosity and high-moisture materials, while the temperature is maintained at a low constant temperature for low-viscosity materials. This flexible adaptation to different states of tar residue avoids the problems of insufficient material flowability or loss of light components due to a single temperature. The self-produced wash oil of the unit is used as a special diluent. The agitator inside the first liquefaction tanks 6 mixes the diluent with the ground and purified tar residue to homogenize and dilute the tar residue. The modified coal tar QI index dynamic ratio control technology is used to control the amount of diluent added, which reduces the viscosity of tar residue, ensures smooth pipeline transportation, and does not introduce foreign impurities. It maximizes the retention of effective components of tar residue, takes into account environmental protection and material stability, and realizes efficient utilization of waste residue resources. It abandons the traditional fixed ratio blending method, and dynamically adjusts the mixing mass ratio of tar residue and coal tar according to the real-time content of quinoline insoluble matter QI of raw coal tar. It can be adapted to raw coal tar of different origins and qualities, greatly improves the stability of modified asphalt product index, and solves the problem of product quality failure caused by raw material fluctuations. The tar residue is continuously heated inside the first liquefaction tank 6 for 3 hours. During the heating process, light distillates such as light oil, phenol oil, naphthalene oil, and wash oil are distilled out from the top of the discharge port of the first liquefaction tank 6 and recovered after condensation. The discharge ports of both first liquefaction tanks 6 are connected to the inlet of the rightmost second liquefaction tank 11, and the discharge port of the rightmost second liquefaction tank 11 is connected to the inlet of the leftmost second liquefaction tank 11. The ammonia water underground tank 8 is connected to the discharge port of the leftmost second liquefaction tank 11. Therefore, during the process of light distillates flowing from the inside of the rightmost second liquefaction tank 11 to the inside of the leftmost second liquefaction tank 11, different components are precipitated and retained inside different second liquefaction tanks 11. The ammonia water discharged from the leftmost second liquefaction tank 11 enters the ammonia water underground tank 8 for storage. Step 5: During the heating process of the tar residue, the heavy asphalt component remains at the bottom of the inner cavity of the first liquefaction tank 6. After the tar residue is heated, the tar extraction pump 10 operates to extract asphalt from the bottom of the inner cavity of the first liquefaction tank 6 and transport it to the coal tar storage tank 9 for storage. Modified asphalt is prepared by a precise thermal condensation reaction at 70℃ and normal pressure for 3 hours. Compared with the traditional high temperature, high pressure and long time polymerization process, the reaction conditions are mild, the equipment requirements are low, the operating energy consumption is low, and the safety risks are small. At the same time, it can effectively control the degree of asphalt polymerization and precisely improve the coking value and bonding performance of modified asphalt. The entire polymerization process, from obtaining raw tar residue from the raw material tank 1 to the modified asphalt entering the coal tar storage tank 9, is subject to closed-loop quality control to ensure high-quality and stable production of modified asphalt. Strict closed-loop control is implemented for core indicators such as softening point, coking value, quinoline insoluble matter, toluene insoluble matter, and ash content to ensure that the finished modified asphalt fully meets the standards used in the carbon and electrolytic aluminum industries, realizing the high-value and resource utilization of tar residue.

[0022] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for preparing modified asphalt using tar residue to improve its quality, characterized in that: The system includes a raw material tank (1), a tar residue bin (2), a coarse grinder (5), a first ultracentrifuge (7), an underground ammonia tank (8), a coal tar storage tank (9), multiple second liquefaction tanks (11), a fine grinder (12), and a second ultracentrifuge (13). The outlet of the raw material tank (1) is connected to two tar residue self-unloading centrifuges (3). The drain outlets of the two tar residue self-unloading centrifuges (3) are connected to the inlet of the tar residue bin (2). The outlets of the two tar residue self-unloading centrifuges (3) are connected to buffer bins (4). The outlets of the two buffer bins (4) are connected to the inlet of the coarse grinder (5). The coarse grinder... (5) The discharge port is connected to the feed port of the fine grinder (12), the discharge port of the fine grinder (12) is connected to the feed port of the first ultracentrifuge (7), the discharge port of the first ultracentrifuge (7) is connected to the feed port of the second ultracentrifuge (13), the discharge port of the second ultracentrifuge (13) is connected to the feed ports of the two first liquefaction tanks (6), the drain ports of the two first liquefaction tanks (6) are all connected to tar extraction pumps (10), the discharge ports of the two tar extraction pumps (10) are all fixedly connected to the feed port of the coal tar storage tank (9), and the discharge ports of the two first liquefaction tanks (6) are all connected to the feed port of the rightmost second liquefaction tank (11).

2. The method for preparing modified asphalt using tar residue to improve its quality according to claim 1, characterized in that: The two adjacent second liquefaction tanks (11) are arranged in such an installation pattern that the discharge port of the right second liquefaction tank (11) is connected to the inlet port of the left second liquefaction tank (11), and the ammonia underground tank (8) is connected to the discharge port of the leftmost second liquefaction tank (11).

3. The method for preparing modified asphalt using tar residue to improve its quality according to claim 1, characterized in that: Step 1: The raw material tank (1) is insulated with a jacket and has an internal agitator to prevent tar residue from settling, condensing or caking; the raw material tank (1) is heated by steam to maintain a temperature of 68°C, and the two first liquefaction tanks (6) are preheated to 70°C.

4. The method for preparing modified asphalt using tar residue to improve its quality according to claim 1, characterized in that: Step 2: Two self-unloading centrifuges (3) extract tar residue and separate solid residue from the tar residue; the discharge port of the self-unloading centrifuges (3) transports the processed tar residue to the inlet of the connected buffer silo (4). The tar residue is left to stand in the buffer silo (4) to allow the tar residue to separate into layers. A decanter is installed inside the buffer silo (4) to drain the upper layer of water.

5. The method for preparing modified asphalt using tar residue to improve its quality according to claim 1, characterized in that: Step 3: The coarse grinding mill (5) extracts tar residue from the two buffer silos (4) for coarse grinding. After being crushed by the coarse grinding mill (5), the tar residue is transported to the fine grinding mill (12) for fine grinding. After being crushed by the fine grinding mill (12), the tar residue is transported to the first ultracentrifuge (7). The first ultracentrifuge (7) performs preliminary filtration on the crushed tar residue. After being filtered by the first ultracentrifuge (7), the tar residue is transported to the second ultracentrifuge (13) for further filtration.

6. The method for preparing modified asphalt using tar residue to improve its quality according to claim 1, characterized in that: Step 4: After purification by the second ultracentrifuge (13), the tar residue is diverted to the two first liquefaction tanks (6). The first liquefaction tank (6) adopts a gradient steam heat exchange temperature control of 65-72℃. The temperature is finely adjusted in real time according to the water content and viscosity of the tar residue. The temperature is appropriately increased for high viscosity and high water content materials. The self-produced wash oil of the device is selected as a special diluent. The dynamic ratio control technology of modified coal tar QI index is used to control the amount of diluent added.

7. The method for preparing modified asphalt using tar residue to improve its quality according to claim 1, characterized in that: Step 5: During the heating process of the tar residue, the heavy asphalt component remains at the bottom of the inner cavity of the first liquefaction tank (6). The tar extraction pump (10) works to extract the asphalt from the bottom of the inner cavity of the first liquefaction tank (6) and transport it to the inside of the coal tar storage tank (9) for storage.

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