Extraction method and extraction equipment for supercritical extraction of coal pitch

Abstract

The invention belongs to the technical field of coal pitch processing, and relates to an extraction method for supercritical extraction of coal pitch, which comprises the following steps: providing liquid coal pitch and a first solution, and mixing the liquid coal pitch with the first solution to form a first mixed solution; providing supercritical carbon dioxide, respectively introducing the first mixed solution and the supercritical carbon dioxide into two ends of a first extractor, carrying out counter-current extraction to obtain a first supernatant and a first precipitate, discharging the first supernatant from the upper end of the first extractor, and discharging the first precipitate from the lower end of the first extractor; performing at least one time of separation treatment on the first supernate to obtain a first extraction substance. The invention further relates to extraction equipment. According to the technical scheme provided by the invention, each component of the coal pitch can be accurately separated, and the product quality of the extracted substance is improved.

Description

Technical Field

[0001] This application relates to the field of coal tar pitch processing technology, and more specifically, to an extraction method and extraction equipment for supercritical extraction of coal tar pitch. Background Technology

[0002] Coal tar pitch is obtained by dry distilling coal in a dry distillation furnace at 450℃~950℃. After the coal tar is distilled and the light components are extracted by atmospheric and vacuum distillation, a black viscous liquid is obtained at the bottom of the vacuum tower, which will solidify at room temperature to form a black solid substance.

[0003] The coal tar pitch was analyzed by colorimetric and mass spectrometric methods. In addition to a large amount of asphaltenes and a small amount of metals and solid waste, the coal tar pitch also contains a large amount of colloids, aromatics (anthracene, phenanthrene, naphthalene, fluorene, acenaphthene, pyrene, phenyl, chlorobenzene, indene, biphenyl), saturated hydrocarbons and other substances. These substances are valuable building materials and chemical raw materials.

[0004] To extract useful substances from coal tar pitch, extraction methods are commonly used to process it. However, traditional extraction methods require a large amount of solvent and equipment to extract a single substance, resulting in complex processes, high operational difficulty, and high production costs. Furthermore, the extracted substance is often contaminated with other materials due to the extensive use of solvent, leading to poor product quality. Summary of the Invention

[0005] The technical problem to be solved by the embodiments of this application is that the existing extraction methods for coal tar pitch are complex, difficult to operate, costly to produce, and produce poor quality extraction products.

[0006] To address the aforementioned technical problems, this application provides a supercritical extraction method for coal tar pitch, employing the following technical solution:

[0007] A supercritical extraction method for coal tar pitch includes the following steps:

[0008] Liquid coal tar pitch and a first solution are provided, and the liquid coal tar pitch and the first solution are mixed to form a first mixed solution;

[0009] Supercritical carbon dioxide is provided, and the first mixed solution and the supercritical carbon dioxide are respectively introduced into both ends of the first extractor to perform countercurrent extraction to obtain a first supernatant and a first precipitate. The first supernatant is discharged from the upper end of the first extractor, and the first precipitate is discharged from the lower end of the first extractor.

[0010] The first supernatant is subjected to at least one separation process to obtain the first extract.

[0011] Furthermore, the liquid coal tar pitch is obtained through the following steps:

[0012] Provide coal tar pitch solids to be processed;

[0013] The coal tar pitch solid is placed in the first storage tank;

[0014] The first storage tank is heated to melt the solid coal tar pitch into liquid coal tar pitch, wherein the heating temperature is 120℃~160℃.

[0015] Furthermore, before the step of introducing the first mixed solution and supercritical carbon dioxide into both ends of the first extractor, the following step is also included:

[0016] The first mixed solution is subjected to a first pressurization treatment, wherein after the first pressurization treatment, the pressure of the first mixed solution is 25 MPa to 35 MPa;

[0017] The carbon dioxide is subjected to a second pressurization treatment to form the supercritical carbon dioxide, wherein the pressure of the supercritical carbon dioxide after the second pressurization treatment is 25 MPa to 35 MPa.

[0018] Furthermore, the first solution comprises a first drug and diesel fuel, wherein the mass percentage concentration of the first drug in the first solution is 1% to 30%; and / or,

[0019] The material of the first drug is selected from at least one of fatty alcohol ether phosphates, polycarboxylic acid higher alcohol esters, carboxylic acids and carboxylates, phosphate esters, fatty alcohol vinyl ethers, alkyl sulfonates, methanol, and toluene; and / or,

[0020] In the first mixed solution, the amount of the first solution added is 1.5% to 2% of the liquid coal tar pitch; and / or,

[0021] The concentration of the supercritical carbon dioxide is 90% to 99.9%; and / or,

[0022] In the first extractor, the ratio of the first mixed solution to the supercritical carbon dioxide is 1:(10-90).

[0023] Furthermore, the first supernatant comprises colloids, aromatics, saturated hydrocarbons, and supercritical carbon dioxide; the step of performing at least one separation treatment on the first supernatant to obtain the first extractable substance includes the following steps:

[0024] The first supernatant is passed into the first separator;

[0025] The first supernatant is subjected to a first separation process in the first separator to obtain a second supernatant and a second precipitate. The pressure of the first separation process is 20 MPa to 25 MPa, and the temperature is 100°C to 115°C.

[0026] The second supernatant is discharged from the upper end of the first separator and introduced into the second separator, and the second precipitate is discharged from the lower end of the first separator, wherein the second precipitate is a colloid;

[0027] The second supernatant is subjected to a second separation process in the second separator to obtain a third supernatant and a third precipitate. The pressure of the second separation process is 10 MPa to 20 MPa and the temperature is 105℃ to 120℃.

[0028] The third supernatant is discharged from the upper end of the second separator and introduced into the third separator, and the third precipitate is discharged from the lower end of the second separator, wherein the third precipitate is an aromatic hydrocarbon;

[0029] The third supernatant is subjected to a third separation process in the third separator to obtain a fourth supernatant and a fourth precipitate, wherein the pressure of the third separation process is 6 MPa to 10 MPa.

[0030] The fourth supernatant is discharged from the upper end of the third separator, and the fourth precipitate is discharged from the lower end of the third separator, wherein the fourth supernatant is carbon dioxide and the fourth precipitate is saturated hydrocarbon.

[0031] Furthermore, after the step of discharging the third precipitate from the lower end of the second separator, the method further includes the following steps:

[0032] A second solution is provided, and the aromatic hydrocarbon is mixed with the second solution to form a second mixed solution;

[0033] Supercritical carbon dioxide is provided, and the second mixed solution and the supercritical carbon dioxide are respectively introduced into both ends of the second extractor to perform countercurrent extraction to form a fifth supernatant and a fifth precipitate. The fifth supernatant is discharged from the upper end of the second extractor, and the fifth precipitate is discharged from the lower end of the second extractor.

[0034] The fifth supernatant is subjected to at least one separation process to obtain the second extract.

[0035] Furthermore, before the step of introducing the second mixed solution and the supercritical carbon dioxide into both ends of the second extractor, the following step is also included:

[0036] The second mixed solution is subjected to a third pressurization treatment, wherein after the third pressurization treatment, the pressure of the first mixed solution is 20 MPa to 25 MPa;

[0037] Carbon dioxide is subjected to a fourth pressurization treatment to form supercritical carbon dioxide, wherein the pressure of the supercritical carbon dioxide after the fourth pressurization treatment is 20 MPa to 25 MPa.

[0038] Furthermore, the second solution comprises a second drug and toluene, wherein the mass percentage concentration of the second drug in the second solution is 1% to 30%; and / or,

[0039] The material of the second drug is selected from at least one of fatty alcohol ether phosphates, carboxylic acids and their salts, sulfonic acids and their sulfonates, methanol, and acetone; and / or,

[0040] In the second mixed solution, the amount of the second solution added is 1.0% to 1.5% of the liquid coal tar pitch; and / or,

[0041] The concentration of the supercritical carbon dioxide is 90% to 99.9%; and / or,

[0042] In the second extractor, the ratio of the second mixed solution to the supercritical carbon dioxide is 1:(10-60).

[0043] Furthermore, the fifth supernatant comprises anthracene, phenanthrene, naphthalene, and supercritical carbon dioxide;

[0044] The step of performing at least one separation treatment on the fifth supernatant to obtain the second extractant includes the following steps:

[0045] The fifth supernatant is then passed into the fourth separator;

[0046] The fifth supernatant is subjected to a fourth separation process in the fourth separator to obtain a sixth supernatant and a sixth precipitate. The pressure of the fourth separation process is 15 MPa to 20 MPa, and the temperature is 85°C to 100°C.

[0047] The sixth supernatant is discharged from the upper end of the fourth separator and introduced into the fifth separator, and the sixth precipitate is discharged from the lower end of the fourth separator, wherein the sixth precipitate is anthracene;

[0048] The sixth supernatant is subjected to a fifth separation process in the fifth separator to obtain a seventh supernatant and a seventh precipitate. The pressure of the fifth separation process is 10 MPa to 15 MPa, and the temperature is 95°C to 110°C.

[0049] The seventh supernatant is discharged from the upper end of the fifth separator and introduced into the sixth separator, while the seventh precipitate is discharged from the lower end of the fifth separator, wherein the seventh precipitate is phenanthrene;

[0050] The seventh supernatant is subjected to a sixth separation process in the sixth separator to obtain an eighth supernatant and an eighth precipitate, wherein the pressure of the sixth separation process is 6 MPa to 10 MPa.

[0051] The eighth supernatant is discharged from the upper end of the sixth separator, and the eighth precipitate is discharged from the lower end of the sixth separator, wherein the eighth supernatant is carbon dioxide and the eighth precipitate is naphthalene.

[0052] To address the aforementioned technical problems, this application also provides an extraction device that employs the following technical solution:

[0053] An extraction apparatus for performing the supercritical extraction method for coal tar pitch as described above.

[0054] Compared with the prior art, the embodiments of this application have the following main advantages:

[0055] This application provides a supercritical extraction method for coal tar pitch, which involves fully mixing liquid coal tar pitch with a first solution, using the first solution to demulsify and strongly disperse and penetrate the coal tar pitch, while also carrying out light components. This avoids severe emulsification caused by mixing supercritical carbon dioxide with coal tar pitch, thereby improving the extraction effect and efficiency of supercritical carbon dioxide.

[0056] By introducing supercritical carbon dioxide and using countercurrent extraction, the useful substances in coal tar pitch are fully dissolved in supercritical carbon dioxide, thereby removing asphaltenes, solid waste, and metals from the coal tar pitch, improving the purity and quality of the extracted substances. Subsequently, through at least one separation process, the useful substances in the coal tar pitch are separated. The operation is simple and does not require the addition of large amounts of solvent, thus improving the quality of the extracted substances. Attached Figure Description

[0057] To more clearly illustrate the solution of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0058] Figure 1 This is a flowchart of the supercritical extraction method for coal tar pitch according to an embodiment of this application;

[0059] Figure 2This is a flowchart illustrating the separation of the first extractable substance according to an embodiment of this application;

[0060] Figure 3 This is a flowchart of the extraction of aromatics according to an embodiment of this application;

[0061] Figure 4 This is a flowchart illustrating the separation of the second extractable substance according to an embodiment of this application;

[0062] Figure 5 This is a process flow diagram of the extraction equipment according to an embodiment of this application.

[0063] Figure label:

[0064] 100. Liquid coal tar pitch output device; 101. First storage tank; 102. Coal tar pitch extraction pump; 200. First solution supply device; 201. First storage tank; 202. First dosing pump; 203. First mixer; 300. First extraction device; 301. First extractor; 302. First separator; 303. Second separator; 304. Third separator; 305. First booster pump; 306. First pressure reducing valve; 307. First heater; 308. Second pressure reducing valve; 309. Second heater; 310. Third pressure reducing valve; 311. Fourth pressure reducing valve; 400. Second solution supply device; 401. Second storage tank; 402. Second dosing pump; 403. Second mixer 500, Second extraction device; 501, Second extractor; 502, Fourth separator; 503, Fifth separator; 504, Sixth separator; 505, Second booster pump; 506, Fifth pressure reducing valve; 507, Third heater; 508, Sixth pressure reducing valve; 509, Fourth heater; 510, Seventh pressure reducing valve; 511, Eighth pressure reducing valve; 600, Supercritical carbon dioxide supply device; 601, Second storage tank; 602, Chiller; 603, Cooling coil; 604, Third booster pump; 605, Fourth booster pump; 700, Steam supply device; 701, First heating coil; 702, Second heating coil; 703, Third heating coil; 800, Coal tar pitch solids. Detailed Implementation

[0065] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0066] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0067] Since matter is composed of particles and forces, and different substances have different particles and forces, their molecular structures also differ. Therefore, coal tar pitch can actually be regarded as a colloidal substance composed of asphaltenes, resins, aromatics, saturated hydrocarbons and gases arranged in rings from the inside out. Among them, asphaltenes have the largest molecular weight, the largest force and the strongest polarity, and are located at the center of various colloidal substances. Other types of substances are arranged in order of molecular weight from the inside out.

[0068] Therefore, this application employs supercritical carbon dioxide, utilizing its strong permeability and solubility, as well as the fact that these properties change with pressure and temperature. This allows it to penetrate between the particles of the colloidal substance. By adjusting the pressure and temperature to a suitable level, supercritical carbon dioxide can dissolve the colloidal substance, thus extracting the relevant extractable substances from the coal tar pitch. Simultaneously, by further adjusting the pressure and temperature to a suitable level, the solubility of supercritical carbon dioxide can be further altered, causing the extractable substances to precipitate from the solution and be extracted, achieving the effect of separating each extractable substance individually.

[0069] Please see Figure 1 As shown, based on the above working principle, this application provides a supercritical extraction method for coal tar pitch, comprising the following steps:

[0070] Step S100: Provide liquid coal tar pitch and a first solution, and mix the liquid coal tar pitch and the first solution to form a first mixed solution.

[0071] Step S200: Supercritical carbon dioxide is provided, and the first mixed solution and the supercritical carbon dioxide are respectively introduced into both ends of the first extractor to perform countercurrent extraction to obtain a first supernatant and a first precipitate. The first supernatant is discharged from the upper end of the first extractor, and the first precipitate is discharged from the lower end of the first extractor.

[0072] In this embodiment, the first precipitate includes asphaltene, solid waste, and other substances with the largest molecular weight, the greatest force, and the strongest polarity that are insoluble, and the first supernatant includes colloids, aromatics, saturated hydrocarbons, and supercritical carbon dioxide.

[0073] Step S300: Perform at least one separation process on the first supernatant to obtain the first extract.

[0074] This application provides a supercritical extraction method for coal tar pitch, which involves fully mixing liquid coal tar pitch with a first solution, using the first solution to demulsify and strongly disperse and penetrate the coal tar pitch, while also carrying out light components. This avoids severe emulsification caused by mixing supercritical carbon dioxide with coal tar pitch, thereby improving the extraction effect and efficiency of supercritical carbon dioxide.

[0075] By introducing supercritical carbon dioxide and using countercurrent extraction, the useful substances in coal tar pitch are fully dissolved in supercritical carbon dioxide, thereby removing asphaltenes, solid waste, and metals from the coal tar pitch, improving the purity and quality of the extracted substances. Subsequently, through at least one separation process, the useful substances in the coal tar pitch are separated. The operation is simple and does not require the addition of large amounts of solvent, thus improving the quality of the extracted substances.

[0076] In some embodiments, the supercritical extraction method for coal tar pitch is described in... Figure 5 The extraction is carried out in the extraction equipment shown, wherein the extraction equipment includes a liquid coal tar pitch output device 100, a first solution supply device 200, a first extraction device 300, a supercritical carbon dioxide supply device 600 and a water vapor supply device 700, the first extraction device 300 includes a first extractor 301, and the height-to-diameter ratio of the first extractor 301 is 10:1.

[0077] Please see Figure 5 As shown, in some embodiments, the liquid coal tar pitch output device 100 includes a first storage tank 101 and a coal tar pitch extraction pump 102. The liquid coal tar pitch in step S100 is obtained through the following steps:

[0078] A coal tar pitch solid 800 to be processed is provided. In this embodiment, the density of the coal tar pitch is 0.90 g / cm³ under normal temperature conditions. 3 ~1.30g / cm 3 Its softening point is between 35℃ and 95℃;

[0079] The coal tar pitch solid 800 is placed in the first storage tank 101;

[0080] The first storage tank 101 is heated to melt the coal tar pitch solid 800 to form liquid coal tar pitch, wherein the temperature of the heating treatment is 120℃~160℃.

[0081] In this embodiment, a first heating coil 701 is provided outside the first storage tank 101. The first heating coil 701 is connected to the steam supply device 700. The steam supply device 700 outputs low-pressure steam or medium-pressure steam into the first heating coil 701 to heat the first storage tank 101, so that the coal tar pitch in the first storage tank 101 melts to form liquid coal tar pitch, which is then extracted by the coal tar pitch extraction pump 102 and moved toward the first extraction device 300.

[0082] In other embodiments, the first heating coil 701 may also be connected to a thermal oil furnace, through which thermal oil is introduced into the first heating coil 701 to heat the first storage tank 101, so that the coal tar pitch in the first storage tank 101 melts to form liquid coal tar pitch.

[0083] In other embodiments, liquid coal tar pitch can be directly transported from the outside to mix with the first solution to form a first mixed solution.

[0084] This application embodiment provides a liquid coal tar pitch output device 100 and related preparation steps to provide coal tar pitch melted to a liquid state for mixing with a first solution. This fully utilizes the first solution to demulsify, strongly disperse, and penetrate the coal tar pitch, thereby increasing the supercritical carbon dioxide extraction rate to meet the needs of continuous large-scale industrial production.

[0085] Please see Figure 5 As shown, in some embodiments, the first solution supply device 200 includes a first storage tank 201, a first dosing pump 202, and a first mixer 203. The first storage tank 201 is connected to the input end of the first dosing pump 202, the output end of the first dosing pump 202 is connected to the lateral inlet of the first mixer 203, the axial inlet of the first mixer 203 is connected to the output end of the coal tar pitch extraction pump 102, and the axial outlet of the first mixer 203 is connected to the first extraction device 300.

[0086] The first solution is stored in the first storage tank 201, wherein the first solution comprises a first drug and diesel oil, which are mixed under normal temperature and pressure conditions.

[0087] In some embodiments, the mass percentage concentration of the first drug in the first solution is 1% to 30%. Specifically, the mass percentage concentration of the first drug can be set to any one of 1%, 2%, 5%, 10%, 15%, 20%, 25%, and 30%, or a range between any two of these values.

[0088] In some embodiments, the material of the first drug is selected from at least one of fatty alcohol ether phosphate, polycarboxylic acid higher alcohol ester, carboxylic acid and carboxylates, phosphate ester, fatty alcohol vinyl ether, alkyl sulfonate, methanol, and toluene.

[0089] Please see Figure 5 As shown, step S100, which involves mixing the liquid coal tar pitch with the first solution to form a first mixed solution, specifically includes the following steps:

[0090] The coal tar extraction pump 102 extracts liquid coal tar and inputs it into the first mixer 203 through the axial inlet;

[0091] The first dosing pump 202 draws out the first solution and inputs it into the first mixer 203 through the side inlet;

[0092] The liquid coal tar pitch and the first solution are thoroughly mixed in the first mixer 203 to form a first mixed solution, which is then output from the axial outlet.

[0093] In some embodiments, the amount of the first solution added to the first mixed solution is 1.5% to 2% of the liquid coal tar pitch. Specifically, the amount of the first solution added is any one or any two values ​​of 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, or 2% of the liquid coal tar pitch.

[0094] In this embodiment, liquid coal tar pitch and a first solution are thoroughly mixed in a first mixer 203 to form a first mixed solution. The first solution is used to demulsify and strongly disperse and penetrate the coal tar pitch, while carrying out light components (such as gums, aromatics, and saturated hydrocarbons). This allows for the separation of asphaltene and solid waste such as metals from the coal tar pitch in a very short time, thereby improving the extraction efficiency of supercritical carbon dioxide and meeting the needs of continuous large-scale industrial production.

[0095] Please see Figure 5 As shown, in some embodiments, the first extraction device 300 further includes a first booster pump 305, which is connected between the top of the first mixer 203 and the first extractor 301.

[0096] In some embodiments, before step S200 introduces the first mixed solution and supercritical carbon dioxide into both ends of the first extractor 301, the step further includes the following step:

[0097] The first mixed solution is subjected to a first pressurization treatment.

[0098] In this embodiment, the first mixed solution is output from the axial outlet of the first mixer 203 to the first booster pump 305. The first booster pump 305 performs a first pressurization process on the first mixed solution. After the first pressurization process is completed, the pressure of the first mixed solution is 25MPa to 35MPa.

[0099] In some embodiments, the supercritical carbon dioxide supply device 600 includes a second storage tank 601, a chiller 602, a cooling coil 603, and a third booster pump 604. The second storage tank 601 is used to store carbon dioxide with a concentration of 90% to 99.9%. The cooling coil 603 is sleeved outside the second storage tank 601 and is connected to the chiller 602. The chiller 602 outputs a cooling medium to the cooling coil 603, causing the carbon dioxide in the second storage tank 601 to change from a gaseous state to a liquid state and be stored in the second storage tank 601. The third booster pump 604 is connected between the bottom of the second storage tank 601 and the bottom of the first extractor 301.

[0100] In some embodiments, before step S200 introduces the first mixed solution and supercritical carbon dioxide into both ends of the first extractor 301, the step further includes the following step:

[0101] The carbon dioxide is subjected to a second pressurization process to form the supercritical carbon dioxide.

[0102] In this embodiment, carbon dioxide is output from the bottom of the second storage tank 601 to the third booster pump 604. The third booster pump 604 performs a second pressurization process on the carbon dioxide. After the second pressurization process is completed, the carbon dioxide is converted into supercritical carbon dioxide. The pressure of the supercritical carbon dioxide is 25MPa to 35MPa.

[0103] Please continue reading. Figure 1 As shown, in some embodiments, after step S200 introduces the first mixed solution and the supercritical carbon dioxide into both ends of the first extractor, the ratio of the first mixed solution to the supercritical carbon dioxide in the first extractor is 1:(10-90). Specifically, the ratio of the first mixed solution to the supercritical carbon dioxide in the first extractor can be set to any one of 1:10, 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90, or a range formed between any two values.

[0104] In this embodiment of the application, since the asphaltenes in coal tar pitch have the largest molecular weight, the largest force, and the strongest polarity, they are difficult to separate. Therefore, by setting the ratio of the first mixed solution to the supercritical carbon dioxide, the asphaltenes and solid waste can be separated in a short time, thereby improving the extraction efficiency of supercritical carbon dioxide.

[0105] Please see Figure 5 As shown, in some embodiments, the first extraction device 300 further includes a second heating coil 702, which is sleeved outside the first extractor 301 and connected to a steam supply device 700. The steam supply device 700 transmits low-pressure or medium-pressure steam to the second heating coil 702, which heats the first extractor 301 to maintain the temperature inside the first extractor 301 above 90°C, ensuring that the coal tar pitch remains liquid and preventing condensation inside the first extractor 301 that could cause blockage.

[0106] In some embodiments, the first mixed solution is introduced at the top of the first extractor 301, and the supercritical carbon dioxide is introduced at the bottom of the first extractor 301. After continuous countercurrent extraction of the first mixed solution and the supercritical carbon dioxide in the first extractor 301, a first supernatant and a first precipitate are obtained. The first supernatant is discharged from the upper end of the first extractor 301, and the first precipitate is discharged from the lower end of the first extractor 301.

[0107] In this embodiment, the first precipitate includes asphaltene, solid waste, and other substances with the largest molecular weight, the greatest force, and the strongest polarity that are insoluble, and the first supernatant includes colloids, aromatics, saturated hydrocarbons, and supercritical carbon dioxide.

[0108] This embodiment of the application adjusts the pressure of the first mixed solution and supercritical carbon dioxide, as well as the temperature within the first extractor 301, to regulate the solubility of supercritical carbon dioxide. This allows the light components of liquid coal tar pitch (such as gums, aromatics, and saturated hydrocarbons) to fully dissolve in the supercritical carbon dioxide, thereby eliminating asphaltenes, solid waste, and metallic substances from the coal tar pitch. Simultaneously, it avoids the addition of additional solvents, improving the purity of the extracted material and enhancing the product quality of the extracted material.

[0109] In some embodiments, the first extraction apparatus includes at least one separator to perform step S300, performing at least one separation process on the first supernatant to obtain a first extractant.

[0110] The embodiments of this application achieve the separation of useful substances in coal tar pitch through at least one separation process. The operation is simple and does not require the addition of a large amount of solvent, thereby improving the product quality of the extracted substances.

[0111] Please see Figure 5 As shown, in some embodiments, the first extraction device 300 further includes a first separator 302, a second separator 303, and a third separator 304 connected in sequence to the first extractor 301. The third separator 304 is connected to the second storage tank 601. A first pressure reducing valve 306 and a first heater 307 are also provided between the first extractor 301 and the first separator 302. A second pressure reducing valve 308 and a second heater 309 are also provided between the first separator 302 and the second separator 303. A third pressure reducing valve 310 is also provided between the second separator 303 and the third separator 304. A fourth pressure reducing valve 311 is also provided between the third separator 304 and the second storage tank 601.

[0112] Please see Figure 2 As shown, in this embodiment, step S300 involves separating the first supernatant at least once to obtain the first extractable substance, specifically including the following steps:

[0113] Step S310: The first supernatant is introduced into the first separator.

[0114] Step S320: The first supernatant is subjected to a first separation process in the first separator to obtain a second supernatant and a second precipitate.

[0115] In this embodiment, the first supernatant is discharged from the first extractor 301 to the first pressure reducing valve 306. The first pressure reducing valve 306 adjusts the pressure of the first supernatant to 20 MPa to 25 MPa. Specifically, the pressure of the first supernatant can be adjusted to any one of 20 MPa, 21 MPa, 22 MPa, 23 MPa, 24 MPa, and 25 MPa, or a range formed between any two of these values.

[0116] The first supernatant enters the first heater 307 after passing through the first pressure reducing valve 306. The first heater 307 adjusts the temperature of the first supernatant to 100℃~115℃. Specifically, the temperature of the first supernatant can be adjusted to any one of 100℃, 110℃, and 115℃ or a range formed between any two of these values.

[0117] Step S330: The second supernatant is discharged from the upper end of the first separator and introduced into the second separator, and the second precipitate is discharged from the lower end of the first separator.

[0118] In this embodiment, the second precipitate is a gel.

[0119] Step S340: The second supernatant is subjected to a second separation process in the second separator to obtain a third supernatant and a third precipitate.

[0120] In this embodiment, the second supernatant is discharged from the first separator 302 to the second pressure reducing valve 308. The second pressure reducing valve 308 adjusts the pressure of the second supernatant to 10 MPa to 20 MPa. Specifically, the pressure of the second supernatant can be adjusted to any one of 10 MPa, 15 MPa, and 20 MPa or a range formed between any two of these values.

[0121] The second supernatant enters the second heater 309 after passing through the second pressure reducing valve 308. The second heater 309 adjusts the temperature of the second supernatant to 105℃~120℃. Specifically, the temperature of the second supernatant can be adjusted to any one of 105℃, 110℃, 115℃, and 120℃, or a range formed between any two of these values.

[0122] Step S350: The third supernatant is discharged from the upper end of the second separator and introduced into the third separator, and the third precipitate is discharged from the lower end of the second separator.

[0123] In this embodiment, the third precipitate is an aromatic hydrocarbon.

[0124] Step S360: The third supernatant is subjected to a third separation process in the third separator to obtain a fourth supernatant and a fourth precipitate.

[0125] In this embodiment, the third supernatant is discharged from the second separator 303 to the third pressure reducing valve 310. The third pressure reducing valve 310 adjusts the pressure of the third supernatant to 6 MPa to 10 MPa. Specifically, the pressure of the third supernatant can be adjusted to any one of 6 MPa, 7 MPa, 8 MPa, 9 MPa, and 10 MPa, or a range formed between any two of these values.

[0126] Step S370: The fourth supernatant is discharged from the upper end of the third separator, and the fourth precipitate is discharged from the lower end of the third separator.

[0127] In this embodiment, the fourth supernatant is carbon dioxide, and the fourth precipitate is saturated hydrocarbon.

[0128] This application embodiment adjusts the pressure and temperature conditions of the separation process to regulate the solubility of different light components of coal tar pitch in supercritical carbon dioxide, thereby separating the useful substances of coal tar pitch one by one. The operation is simple and does not require the addition of a large amount of solvent, thus improving the product quality of the extracted substances.

[0129] In some embodiments, the following steps are also included:

[0130] In step S380, the fourth supernatant is discharged into the second storage tank after being subjected to depressurization.

[0131] In this embodiment, the fourth supernatant is discharged from the third separator 304 to the fourth pressure reducing valve 311. The fourth pressure reducing valve 311 adjusts the pressure of the fourth supernatant to 7 MPa to 8 MPa. Specifically, the pressure of the fourth supernatant can be adjusted to any one of 7 MPa, 7.5 MPa, and 8 MPa, or a range formed between any two of these values.

[0132] In this embodiment, the fourth supernatant is cooled in the second storage tank 601 to form liquid carbon dioxide, which is then pressurized to form supercritical carbon dioxide and reintroduced into the first extractor 301 for reverse extraction.

[0133] This embodiment of the application, by connecting the third separator 304 to the second storage tank 601, recovers excess carbon dioxide and reuses it after cooling, thereby reducing production costs.

[0134] Please see Figure 5 As shown, in some embodiments, the extraction device further includes a second solution supply device 400 and a second extraction device 500, wherein the second extraction device 500 includes a second extractor 501 with a height-to-diameter ratio of 5:1, and the second solution supply device 400 is connected between the second separator 303 and the second extractor 501 to provide a second solution for mixing with the aromatics in the second separator 303.

[0135] Please see Figure 3 As shown, in some embodiments, after the third precipitate is discharged from the lower end of the second separator in step S350, the following steps are further included:

[0136] Step S351: Provide a second solution, and mix the aromatic hydrocarbon with the second solution to form a second mixed solution.

[0137] Step S352: Supercritical carbon dioxide is provided, and the second mixed solution and the supercritical carbon dioxide are respectively introduced into both ends of the second extractor to perform countercurrent extraction to form a fifth supernatant and a fifth precipitate. The fifth supernatant is discharged from the upper end of the second extractor, and the fifth precipitate is discharged from the lower end of the second extractor.

[0138] In this embodiment, the fifth precipitate includes heavy aromatic hydrocarbons, and the fifth supernatant includes anthracene, phenanthrene, naphthalene, and supercritical carbon dioxide.

[0139] Step S353: Perform at least one separation process on the fifth supernatant to obtain the second extract.

[0140] In this embodiment, a second solution is further added to demulsify and disperse the aromatics, while simultaneously carrying out light components (such as anthracene, phenanthrene, and naphthalene). This avoids severe emulsification caused by mixing supercritical carbon dioxide with aromatics, thereby improving the extraction effect and efficiency of supercritical carbon dioxide.

[0141] Please see Figure 5 As shown, in some embodiments, the second solution supply device 400 includes a second storage tank 401, a second dosing pump 402, and a second mixer 403. The second storage tank 401 is connected to the input end of the second dosing pump 402, the output end of the second dosing pump 402 is connected to the lateral inlet of the second mixer 403, the axial inlet of the second mixer 403 is connected to the bottom of the second separator 303, and the axial outlet of the second mixer 403 is connected to the second extraction device 500.

[0142] The second solution is stored in the second storage tank 401, wherein the second solution comprises a second drug and toluene, and the second drug and toluene are mixed under normal temperature and pressure conditions to form the solution.

[0143] In some embodiments, the mass percentage concentration of the second drug in the second solution is 1% to 30%. Specifically, the mass percentage concentration of the second drug can be set to any one of 1%, 2%, 5%, 10%, 15%, 20%, 25%, and 30%, or a range between any two values.

[0144] In some embodiments, the material of the second drug is selected from at least one of fatty alcohol ether phosphates, carboxylic acids and carboxylates, sulfonic acids and sulfonates, methanol, and acetone.

[0145] Please see Figure 5 As shown, step S352, which involves mixing the aromatic hydrocarbon with the second solution to form a second mixed solution, specifically includes the following steps:

[0146] The second separator 303 feeds aromatics from the axial inlet into the second mixer 403;

[0147] The second dosing pump 402 draws out the second solution and feeds it into the second mixer 403 through the side inlet;

[0148] The aromatic hydrocarbon and the second solution are thoroughly mixed in the second mixer 403 to form a second mixed solution, which is then output from the axial outlet.

[0149] In some embodiments, the amount of the second solution added to the second mixed solution is 1.0% to 1.5% of the liquid coal tar pitch. Specifically, the amount of the first solution added is any one or any two of the following values: 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, and 1.5% of the liquid coal tar pitch.

[0150] In this embodiment, aromatics and a second solution are thoroughly mixed in a second mixer 403 to form a second mixed solution. The second solution is used to demulsify, strongly disperse, and penetrate the aromatics, while simultaneously carrying out light components (such as anthracene, phenanthrene, and naphthalene). This allows for the separation of heavy aromatics from the aromatics in a very short time, thereby improving the extraction efficiency of supercritical carbon dioxide and meeting the needs of continuous large-scale industrial production.

[0151] Please see Figure 5 As shown, in some embodiments, the second extraction device 500 further includes a second booster pump 505, which is connected between the top of the second mixer 403 and the second extractor 501.

[0152] In some embodiments, before step S352 introduces the second mixed solution and the supercritical carbon dioxide into both ends of the second extractor 501, the step further includes the following step:

[0153] The second mixed solution is subjected to a third pressurization treatment.

[0154] In this embodiment, the second mixed solution is output from the axial outlet of the second mixer 403 to the second booster pump 505. The second booster pump 505 performs a third pressurization process on the second mixed solution. After the third pressurization process is completed, the pressure of the second mixed solution is 20MPa to 25MPa.

[0155] In some embodiments, the supercritical carbon dioxide supply device 600 further includes a fourth booster pump 605, which is connected between the bottom of the second storage tank 601 and the bottom of the second extractor 501.

[0156] In some embodiments, before step S352 introduces the second mixed solution and the supercritical carbon dioxide into both ends of the second extractor 501, the step further includes the following step:

[0157] The carbon dioxide is subjected to a fourth pressurization process to form the supercritical carbon dioxide.

[0158] In this embodiment, carbon dioxide is output from the bottom of the second storage tank 601 to the fourth booster pump 605. The fourth booster pump 605 performs a fourth pressurization process on the carbon dioxide. After the fourth pressurization process is completed, the carbon dioxide is converted into supercritical carbon dioxide. The pressure of the supercritical carbon dioxide is 25MPa to 35MPa.

[0159] Please continue reading. Figure 1 As shown, in some embodiments, after step S352 introduces the second mixed solution and the supercritical carbon dioxide into both ends of the second extractor 501, the ratio of the second mixed solution to the supercritical carbon dioxide in the second extractor 501 is 1:(10-60). Specifically, the ratio of the second mixed solution to the supercritical carbon dioxide in the second extractor 501 can be set to any one of 1:10, 1:20, 1:30, 1:40, 1:50, 1:60, or a range formed between any two values.

[0160] In this embodiment, since the heavy aromatics in the aromatics have relatively small molecular weight, strength, and polarity compared to asphaltenes, they are easier to separate. Therefore, by setting the ratio of the second mixed solution to the supercritical carbon dioxide, the heavy aromatics can be separated in a short time, thereby improving the extraction efficiency of supercritical carbon dioxide.

[0161] Please see Figure 5 As shown, in some embodiments, the second extraction device 500 further includes a third heating coil 703, which is sleeved outside the second extractor 501 and connected to a steam supply device 700. The steam supply device 700 transmits low-pressure or medium-pressure steam to the third heating coil 703, which heats the second extractor 501 to maintain the temperature inside the second extractor 501 above 75°C, thereby maintaining good fluidity of the aromatics and preventing condensation and blockage inside the second extractor 501.

[0162] In some embodiments, the second mixed solution is incorporated at the top of the second extractor 501, and the supercritical carbon dioxide is introduced from the bottom of the second extractor 501. After continuous countercurrent extraction of the second mixed solution and the supercritical carbon dioxide in the second extractor 501, a fifth supernatant and a fifth precipitate are obtained. The fifth supernatant is discharged from the upper end of the second extractor 501, and the fifth precipitate is discharged from the lower end of the second extractor 501.

[0163] In this embodiment, the fifth precipitate includes heavy aromatic hydrocarbons, and the fifth supernatant includes anthracene, phenanthrene, naphthalene, and supercritical carbon dioxide.

[0164] In this embodiment, the solubility of supercritical carbon dioxide is adjusted by regulating the pressure of the second mixed solution and the supercritical carbon dioxide, as well as the temperature within the second extractor 501. This allows the light components (such as anthracene, phenanthrene, and naphthalene) in the aromatics to dissolve fully in the supercritical carbon dioxide, while excluding the heavy aromatics. At the same time, the addition of additional solvents is avoided, thereby improving the purity of the extracted substance and the product quality of the extracted substance.

[0165] In some embodiments, the second extraction apparatus includes at least one separator to perform step S353, performing at least one separation process on the fifth supernatant to obtain a second extractant.

[0166] The embodiments of this application achieve the separation of useful substances from heavy aromatics through at least one separation process. The operation is simple and does not require the addition of a large amount of solvent, thereby improving the product quality of the extracted substances.

[0167] Please see Figure 5 As shown, in some embodiments, the second extraction device 500 further includes a fourth separator 502, a fifth separator 503, and a sixth separator 504 connected in sequence to the second extractor 501. The sixth separator 504 is connected to the second storage tank 601. A fifth pressure reducing valve 506 and a third heater 507 are also provided between the second extractor 501 and the fourth separator 502. A sixth pressure reducing valve 508 and a fourth heater 509 are also provided between the fourth separator 502 and the fifth separator 503. A seventh pressure reducing valve 510 is also provided between the fifth separator 503 and the sixth separator 504. An eighth pressure reducing valve 511 is also provided between the sixth separator 504 and the second storage tank 601.

[0168] Please see Figure 4 As shown, in this embodiment, step S353 involves at least one separation process on the fifth supernatant to obtain the second extractant, specifically including the following steps:

[0169] Step S3531: The fifth supernatant is introduced into the fourth separator.

[0170] Step S3532: The fifth supernatant is subjected to a fourth separation process in the fourth separator to obtain a sixth supernatant and a sixth precipitate.

[0171] In this embodiment, the fifth supernatant is discharged from the second extractor 501 to the fifth pressure reducing valve 506. The fifth pressure reducing valve 506 adjusts the pressure of the fifth supernatant to 15MPa to 20MPa. Specifically, the pressure of the fifth supernatant can be adjusted to any one or any two of the following values: 15MPa, 16MPa, 17MPa, 18MPa, 19MPa, and 20MPa.

[0172] The fifth supernatant enters the third heater 507 after passing through the fifth pressure reducing valve 506. The third heater 507 adjusts the temperature of the fifth supernatant to 85℃~100℃. Specifically, the temperature of the fifth supernatant can be adjusted to any one of 85℃, 90℃, 95℃, and 100℃ or a range formed between any two of these values.

[0173] Step S3533: The sixth supernatant is discharged from the upper end of the fourth separator and introduced into the fifth separator, and the sixth precipitate is discharged from the lower end of the fourth separator.

[0174] In this embodiment, the sixth precipitate is anthracene.

[0175] Step S3534: The sixth supernatant is subjected to a fifth separation process in the fifth separator to obtain a seventh supernatant and a seventh precipitate.

[0176] In this embodiment, the sixth supernatant is discharged from the fifth separator 503 to the sixth pressure reducing valve 508. The sixth pressure reducing valve 508 adjusts the pressure of the sixth supernatant to 10MPa to 15MPa. Specifically, the pressure of the sixth supernatant can be adjusted to any one or any two of the following values: 10MPa, 11MPa, 12MPa, 13MPa, 14MPa, and 25MPa.

[0177] The sixth supernatant enters the fourth heater 509 after passing through the sixth pressure reducing valve 508. The fourth heater 509 adjusts the temperature of the sixth supernatant to 95℃~110℃. Specifically, the temperature of the sixth supernatant can be adjusted to any one of 95℃, 100℃, 1055℃, and 110℃, or a range formed between any two of these values.

[0178] Step S3535: The seventh supernatant is discharged from the upper end of the fifth separator and introduced into the sixth separator, while the seventh precipitate is discharged from the lower end of the fifth separator.

[0179] In this embodiment, the seventh precipitate is phenanthrene.

[0180] Step S3536: The seventh supernatant is subjected to a sixth separation process in the sixth separator to obtain an eighth supernatant and an eighth precipitate.

[0181] In this embodiment, the seventh supernatant is discharged from the fifth separator 503 to the seventh pressure reducing valve 510. The seventh pressure reducing valve 510 adjusts the pressure of the seventh supernatant to 6 MPa to 10 MPa. Specifically, the pressure of the seventh supernatant can be adjusted to any one of 6 MPa, 7 MPa, 8 MPa, 9 MPa, and 10 MPa, or a range formed between any two of these values.

[0182] Step S3537: The eighth supernatant is discharged from the upper end of the sixth separator, and the eighth precipitate is discharged from the lower end of the sixth separator.

[0183] In this embodiment, the eighth supernatant is carbon dioxide, and the eighth precipitate is naphthalene.

[0184] This application embodiment adjusts the pressure and temperature conditions of the separation process to regulate the solubility of different light components of aromatics in supercritical carbon dioxide, thereby separating the useful substances of aromatics one by one. The operation is simple and does not require the addition of a large amount of solvent, thus improving the product quality of the extracted substances.

[0185] In some embodiments, in step S3538, the eighth supernatant is discharged into the second storage tank after being subjected to depressurization treatment.

[0186] In this embodiment, the eighth supernatant is discharged from the sixth separator 504 to the eighth pressure reducing valve 511. The eighth pressure reducing valve 511 adjusts the pressure of the eighth supernatant to 7 MPa to 8 MPa. Specifically, the pressure of the eighth supernatant can be adjusted to any one of 7 MPa, 7.5 MPa, and 8 MPa, or a range formed between any two of these values.

[0187] In this embodiment, the eighth supernatant is cooled in the second storage tank 601 to form liquid carbon dioxide, which is then pressurized and reformed into supercritical carbon dioxide before being reintroduced into the second extractor 501 for reverse extraction. This embodiment of the application, by connecting the sixth separator 504 to the second storage tank 601, recovers excess carbon dioxide and allows for repeated cooling and reuse, thus reducing production costs.

[0188] Based on the supercritical extraction method for coal tar pitch provided above, this application also provides an extraction apparatus for performing the extraction method described above.

[0189] Please see Figure 5As shown, in some embodiments, the extraction equipment includes a liquid coal tar pitch output device 100, a first solution supply device 200, a first extraction device 300, a second solution supply device 400, a second extraction device 500, a supercritical carbon dioxide supply device 600, and a steam supply device 700.

[0190] The liquid coal tar pitch output device 100 includes a first storage tank 101 and a coal tar pitch extraction pump 102. The first storage tank 101 is connected to the input end of the coal tar pitch extraction pump 102. The first storage tank 101 is used to store coal tar pitch solids 800 to be processed.

[0191] The first solution supply device 200 includes a first storage tank 201, a first dosing pump 202, and a first mixer 203. The first storage tank 201 is connected to the input end of the first dosing pump 202, the output end of the first dosing pump 202 is connected to the lateral inlet of the first mixer 203, the axial inlet of the first mixer 203 is connected to the output end of the coal tar pitch extraction pump 102, and the axial outlet of the first mixer 203 is connected to the first extraction device 300.

[0192] The first extraction device 300 includes a first extractor 301 and a first separator 302, a second separator 303 and a third separator 304 connected in sequence to the output end of the first extractor 301. The input end of the first extractor 301 is connected to the axial outlet of the first mixer 203, and the third separator 304 is connected to the supercritical carbon dioxide supply device 600.

[0193] The second solution supply device 400 includes a second storage tank 401, a second dosing pump 402, and a second mixer 403. The second storage tank 401 is connected to the input end of the second dosing pump 402, the output end of the second dosing pump 402 is connected to the lateral inlet of the second mixer 403, the axial inlet of the second mixer 403 is connected to the bottom of the second separator 303, and the axial outlet of the second mixer 403 is connected to the second extraction device 500.

[0194] The second extraction device 500 includes a second extractor 501 and a fourth separator 502, a fifth separator 503 and a sixth separator 504 connected in sequence to the output end of the second extractor 501. The input end of the second extractor 501 is connected to the axial outlet of the second mixer 403, and the sixth separator 504 is connected to the supercritical carbon dioxide supply device 600.

[0195] The supercritical carbon dioxide supply device 600 includes a second storage tank 601, a chiller 602, a cooling coil 603, a third booster pump 604, and a fourth booster pump 605. The second storage tank 601 is used to store carbon dioxide and is connected to a third separator 304 and a sixth separator 504. The cooling coil 603 is sleeved outside the second storage tank 601 and is connected to the chiller 602. The chiller 602 outputs a cooling medium to the cooling coil 603, causing the carbon dioxide in the second storage tank 601 to change from a gaseous state to a liquid state and be stored in the second storage tank 601. The third booster pump 604 is connected between the bottom of the second storage tank 601 and the bottom of the first extractor 301, and the fourth booster pump 605 is connected between the bottom of the second storage tank 601 and the bottom of the second extractor 501.

[0196] The steam supply device 700 is connected to the first heating coil 701, the second heating coil 702, and the third heating coil 703 respectively. The first heating coil 701 is used to heat the first storage tank 101 so that the coal tar pitch melts into a liquid state; the second heating coil 702 is used to heat the first extractor 301 to prevent the coal tar pitch from cooling and solidifying; and the third heating coil 703 is used to heat the second extractor 501 to ensure the flowability of aromatics.

[0197] This application provides an extraction device that, in conjunction with a supercritical extraction method for coal tar pitch, can improve the extraction effect and efficiency of supercritical carbon dioxide, thereby increasing the purity and product quality of the extracted substances. Simultaneously, through at least one separation process, useful substances in the coal tar pitch can be separated. The operation is simple, does not require the addition of large amounts of solvent, and further improves the product quality of the extracted substances.

[0198] Obviously, the embodiments described above are only some embodiments of this application, not all embodiments. The accompanying drawings show preferred embodiments of this application, but do not limit the patent scope of this application. This application can be implemented in many different forms; rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this application's specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the scope of patent protection of this application.

Claims

1. A supercritical extraction method for coal tar pitch, characterized in that, Includes the following steps: Liquid coal tar pitch and a first solution are provided, and the liquid coal tar pitch and the first solution are mixed to form a first mixed solution; Supercritical carbon dioxide is provided, and the first mixed solution and the supercritical carbon dioxide are respectively introduced into both ends of the first extractor to perform countercurrent extraction to obtain a first supernatant and a first precipitate. The first supernatant is discharged from the upper end of the first extractor, and the first precipitate is discharged from the lower end of the first extractor. The first supernatant is subjected to at least one separation process to obtain the first extract.

2. The supercritical extraction method for coal tar pitch according to claim 1, characterized in that, The liquid coal tar pitch is obtained through the following steps: Provide coal tar pitch solids to be processed; The coal tar pitch solid is placed in the first storage tank; The first storage tank is heated to melt the solid coal tar pitch into liquid coal tar pitch, wherein the heating temperature is 120℃~160℃.

3. The supercritical extraction method for coal tar pitch according to claim 1, characterized in that, Before the step of introducing the first mixed solution and supercritical carbon dioxide into both ends of the first extractor, the following steps are also included: The first mixed solution is subjected to a first pressurization treatment, wherein after the first pressurization treatment, the pressure of the first mixed solution is 25 MPa to 35 MPa; The carbon dioxide is subjected to a second pressurization treatment to form the supercritical carbon dioxide, wherein the pressure of the supercritical carbon dioxide after the second pressurization treatment is 25 MPa to 35 MPa.

4. The supercritical extraction method for coal tar pitch according to claim 1, characterized in that, The first solution comprises a first drug and diesel fuel, wherein the mass percentage concentration of the first drug in the first solution is 1% to 30%; and / or, The material of the first drug is selected from at least one of fatty alcohol ether phosphates, polycarboxylic acid higher alcohol esters, carboxylic acids and carboxylates, phosphate esters, fatty alcohol vinyl ethers, alkyl sulfonates, methanol, and toluene; and / or, In the first mixed solution, the amount of the first solution added is 1.5% to 2% of the liquid coal tar pitch; and / or, The concentration of the supercritical carbon dioxide is 90% to 99.9%; and / or, In the first extractor, the ratio of the first mixed solution to the supercritical carbon dioxide is 1:(10-90).

5. The supercritical extraction method for coal tar pitch according to claim 1, characterized in that, The first supernatant includes colloids, aromatics, saturated hydrocarbons and supercritical carbon dioxide; The step of performing at least one separation treatment on the first supernatant to obtain the first extractable substance includes the following steps: The first supernatant is passed into the first separator; The first supernatant is subjected to a first separation process in the first separator to obtain a second supernatant and a second precipitate. The pressure of the first separation process is 20 MPa to 25 MPa, and the temperature is 100°C to 115°C. The second supernatant is discharged from the upper end of the first separator and introduced into the second separator, and the second precipitate is discharged from the lower end of the first separator, wherein the second precipitate is a colloid; The second supernatant is subjected to a second separation process in the second separator to obtain a third supernatant and a third precipitate. The pressure of the second separation process is 10 MPa to 20 MPa and the temperature is 105℃ to 120℃. The third supernatant is discharged from the upper end of the second separator and introduced into the third separator, and the third precipitate is discharged from the lower end of the second separator, wherein the third precipitate is an aromatic hydrocarbon; The third supernatant is subjected to a third separation process in the third separator to obtain a fourth supernatant and a fourth precipitate, wherein the pressure of the third separation process is 6 MPa to 10 MPa. The fourth supernatant is discharged from the upper end of the third separator, and the fourth precipitate is discharged from the lower end of the third separator, wherein the fourth supernatant is carbon dioxide and the fourth precipitate is saturated hydrocarbon.

6. The supercritical extraction method for coal tar pitch according to claim 5, characterized in that, After the step of discharging the third precipitate from the lower end of the second separator, the method further includes the following steps: A second solution is provided, and the aromatic hydrocarbon is mixed with the second solution to form a second mixed solution; Supercritical carbon dioxide is provided, and the second mixed solution and the supercritical carbon dioxide are respectively introduced into both ends of the second extractor to perform countercurrent extraction to form a fifth supernatant and a fifth precipitate. The fifth supernatant is discharged from the upper end of the second extractor, and the fifth precipitate is discharged from the lower end of the second extractor. The fifth supernatant is subjected to at least one separation process to obtain the second extract.

7. The supercritical extraction method for coal tar pitch according to claim 6, characterized in that, Before the step of introducing the second mixed solution and the supercritical carbon dioxide into both ends of the second extractor, the following steps are also included: The second mixed solution is subjected to a third pressurization treatment, wherein after the third pressurization treatment, the pressure of the first mixed solution is 20 MPa to 25 MPa; Carbon dioxide is subjected to a fourth pressurization treatment to form supercritical carbon dioxide, wherein the pressure of the supercritical carbon dioxide after the fourth pressurization treatment is 20 MPa to 25 MPa.

8. The supercritical extraction method for coal tar pitch according to claim 6, characterized in that, The second solution comprises a second drug and toluene, wherein the mass percentage concentration of the second drug in the second solution is 1% to 30%; and / or, The material of the second drug is selected from at least one of fatty alcohol ether phosphates, carboxylic acids and their salts, sulfonic acids and their sulfonates, methanol, and acetone; and / or, In the second mixed solution, the amount of the second solution added is 1.0% to 1.5% of the liquid coal tar pitch; and / or, The concentration of the supercritical carbon dioxide is 90% to 99.9%; and / or, In the second extractor, the ratio of the second mixed solution to the supercritical carbon dioxide is 1:(10-60).

9. The supercritical extraction method for coal tar pitch according to claim 6, characterized in that, The fifth supernatant includes anthracene, phenanthrene, naphthalene, and supercritical carbon dioxide; The step of performing at least one separation treatment on the fifth supernatant to obtain the second extractant includes the following steps: The fifth supernatant is then introduced into the fourth separator; The fifth supernatant is subjected to a fourth separation process in the fourth separator to obtain a sixth supernatant and a sixth precipitate. The pressure of the fourth separation process is 15 MPa to 20 MPa, and the temperature is 85°C to 100°C. The sixth supernatant is discharged from the upper end of the fourth separator and introduced into the fifth separator, and the sixth precipitate is discharged from the lower end of the fourth separator, wherein the sixth precipitate is anthracene; The sixth supernatant is subjected to a fifth separation process in the fifth separator to obtain a seventh supernatant and a seventh precipitate. The pressure of the fifth separation process is 10 MPa to 15 MPa, and the temperature is 95°C to 110°C. The seventh supernatant is discharged from the upper end of the fifth separator and introduced into the sixth separator, while the seventh precipitate is discharged from the lower end of the fifth separator, wherein the seventh precipitate is phenanthrene; The seventh supernatant is subjected to a sixth separation process in the sixth separator to obtain an eighth supernatant and an eighth precipitate, wherein the pressure of the sixth separation process is 6 MPa to 10 MPa. The eighth supernatant is discharged from the upper end of the sixth separator, and the eighth precipitate is discharged from the lower end of the sixth separator, wherein the eighth supernatant is carbon dioxide and the eighth precipitate is naphthalene.

10. An extraction apparatus, characterized in that, Used to perform the supercritical extraction method for coal tar pitch as described in any one of claims 1 to 9.

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