Plasma-assisted aromatic hydrocarbon extraction and separation system and operation process thereof

Abstract

The invention provides an aromatic hydrocarbon extraction and separation system based on plasma assistance and an operation process thereof, and relates to the technical field of petrochemical industry and coal chemical industry, the aromatic hydrocarbon extraction and separation system sequentially comprises a plasma activation device, an extraction distillation tower, a solvent recovery tower, a plasma-carclazyte combined device and a rectifying tower according to a raw material treatment sequence, the plasma activation device is used for selectively activating the raw materials to enhance the polarity of aromatic hydrocarbon; the extractive distillation tower is used for carrying out solvent extraction on the activated raw materials and separating aromatic hydrocarbons from non-aromatic hydrocarbons; the solvent recovery tower is used for separating the aromatic hydrocarbon mixture collected at the bottom of the extractive distillation tower to obtain aromatic hydrocarbon and a recovery solvent; the plasma-carclazyte combined device is used for activating and purifying the separated aromatic hydrocarbon; the rectifying tower is used for rectifying the purified aromatic hydrocarbon to obtain an aromatic hydrocarbon product. The method has the advantages of high separation efficiency, low energy consumption and environmental friendliness, and is suitable for aromatic hydrocarbon separation of high-difficulty raw materials such as heavy oil and coal tar.

Description

Technical Field

[0001] The present invention relates to the technical field of petrochemical industry and coal chemical industry, and in particular to a plasma-assisted aromatics extraction and separation system and an operating process thereof. Background Art

[0002] Aromatic hydrocarbons (such as benzene, toluene, and xylene) are important basic chemicals in the petrochemical and coal chemical industries, and are widely used in industries such as synthetic fibers, plastics, rubber, and dyes. Traditional methods for separating aromatic hydrocarbons include solvent extraction, distillation, and adsorption.

[0003] However, these separation methods have the following problems when processing complex raw materials (such as heavy oil and coal tar): (1) High energy consumption: Traditional distillation and extraction processes usually need to be carried out at high temperature and high pressure, resulting in high energy consumption; (2) Low efficiency: For aromatic and non-aromatic components with similar boiling points (such as benzene and cyclohexane), the separation efficiency of traditional methods is low; (3) Environmental pollution: The chemical solvents used in the solvent extraction process (such as cyclopentane and N-methylpyrrolidone) will cause environmental pollution; (4) Poor adaptability to raw materials: Traditional methods are not effective in treating difficult raw materials such as heavy oil and coal tar.

[0004] In recent years, plasma technology, as an emerging molecular activation method, has shown great potential in fields such as material modification and waste gas treatment. Plasma can generate high-energy electrons, ions, and free radicals at room temperature and pressure, selectively activating target molecules and thus changing their chemical properties.

[0005] However, the application of plasma technology in the field of aromatics separation has not been fully developed.

[0006] In view of this, the present invention is proposed. Summary of the Invention

[0007] One of the objectives of the present invention is to provide a plasma-assisted aromatics extraction and separation system with the advantages of high separation efficiency, low energy consumption and environmental friendliness. It is particularly suitable for the separation of aromatics from difficult raw materials such as heavy oil and coal tar, and can significantly improve the comprehensive economic benefits of aromatics separation and the sustainable development potential of the process.

[0008] The second object of the present invention is to provide an operating process of an aromatics extraction and separation system based on plasma assistance, which can efficiently separate aromatics and non-aromatics from complex raw materials such as heavy oil and coal tar, solving the problems of high energy consumption and low efficiency in traditional processes, and achieving the technical effects of efficient separation of aromatics, energy saving and environmental protection.

[0009] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted:

[0010] In the first aspect, a plasma-assisted aromatics extraction and separation system comprises, in order of raw material processing, a plasma activation device, an extractive distillation tower, a solvent recovery tower, a plasma-clay combined device, and a distillation tower:

[0011] The plasma activation device is used to selectively activate the raw materials to enhance the polarity of aromatic hydrocarbons;

[0012] The extractive distillation tower is used to perform solvent extraction on the activated raw materials to separate aromatic hydrocarbons and non-aromatic hydrocarbons;

[0013] The solvent recovery tower is used to separate the aromatic hydrocarbon mixture collected at the bottom of the extractive distillation tower to obtain aromatic hydrocarbons and recovered solvent;

[0014] The plasma-white clay combined device is used to activate and purify the separated aromatic hydrocarbons;

[0015] The distillation tower is used to distill the purified aromatics to obtain aromatic products.

[0016] Furthermore, an extraction and feeding device is provided before the plasma activation device to ensure that the raw materials are uniformly and stably transported to the plasma activation device;

[0017] Preferably, the plasma activation device adopts dielectric barrier discharge, radio frequency plasma and / or microwave plasma.

[0018] Furthermore, the system is further provided with an extractive distillation tower to extractively distill the mixture of aromatic hydrocarbons and non-aromatic hydrocarbons collected at the top of the extractive distillation tower, and recover the aromatic hydrocarbons therein and return them to the plasma activation device;

[0019] Preferably, the system is further provided with a control module to control the operating parameters of each device;

[0020] Preferably, the control module includes at least one of a power regulation module, a solvent flow control module, a temperature control module and a pressure control module;

[0021] Preferably, the power regulation module is used to control the plasma generation power and activation time;

[0022] Preferably, the solvent flow control module is used to adjust the solvent injection rate in the extractive distillation column;

[0023] Preferably, the temperature control module is used to maintain the temperature of the extractive distillation column and the rectifying column;

[0024] Preferably, the pressure control module is used to adjust the pressure of the extractive distillation column and the rectifying column.

[0025] Furthermore, the plasma-clay combined device includes a plasma reaction zone for activating aromatic hydrocarbon molecules and a clay adsorption zone for removing polar impurities;

[0026] Preferably, the distillation tower includes at least one of a benzene distillation tower, a toluene distillation tower and a xylene distillation tower.

[0027] Furthermore, a plasma-assisted cracking unit is provided after the distillation tower to dealkylate heavy aromatics to generate light aromatics which are returned to the plasma activation unit;

[0028] Preferably, the plasma-assisted cracking device adopts dielectric barrier discharge, radio frequency plasma and / or microwave plasma.

[0029] In a second aspect, an operation process of the system described in any one of the above items comprises the following steps:

[0030] The raw materials are first selectively activated by a plasma activation device, and then separated into aromatics and non-aromatics by an extractive distillation tower. The solvent is then recovered by a solvent recovery tower. After that, they are activated and purified by a plasma-white clay combined device, and then distilled by a distillation tower to obtain aromatic products.

[0031] Furthermore, the plasma power of the plasma activation device is 1kW to 10kW;

[0032] Preferably, the gas atmosphere of the plasma activation device is a mixture of argon and oxygen;

[0033] Preferably, the volume ratio of argon to oxygen in the mixed gas is 9:1;

[0034] Preferably, the flow rate of the mixed gas is 10 L / min;

[0035] Preferably, the selective activation time is 1 minute to 5 minutes.

[0036] Furthermore, the extraction solvent used in the extractive distillation column is sulfolane or sulfolane compounded alcohol ether;

[0037] Preferably, the mass ratio of the extraction solvent to the raw material is 1:5 to 1:10;

[0038] Preferably, the extraction temperature of the extractive distillation tower is 80° C. to 200° C., and the extraction pressure is 0.1 MPa to 1 MPa.

[0039] Furthermore, the temperature of the benzene distillation tower in the distillation tower is 110° C. to 120° C., and the pressure is 0.1 MPa to 0.5 MPa;

[0040] Preferably, the temperature of the toluene distillation tower in the distillation tower is 135° C. to 145° C., and the pressure is 0.1 MPa to 0.5 MPa;

[0041] Preferably, the temperature of the xylene distillation tower in the distillation tower is 140° C. to 150° C., and the pressure is 0.1 MPa to 0.5 MPa.

[0042] Furthermore, the operation process further comprises the following steps:

[0043] The mixture of aromatic hydrocarbons and non-aromatic hydrocarbons collected from the top of the extractive distillation tower is subjected to extractive distillation in an extractive distillation tower, and the aromatic hydrocarbons are recovered and returned to the plasma activation device;

[0044] The heavy aromatics obtained after distillation are subjected to a directional dealkylation reaction in a plasma-assisted cracking unit to generate light aromatics which are returned to the plasma activation unit.

[0045] Compared with the prior art, the present invention has at least the following beneficial effects:

[0046] The present invention provides a plasma-assisted aromatics extraction and separation system that combines plasma activation technology with an extractive distillation process. By selectively activating aromatic molecules using plasma at room temperature and pressure, the system can not only significantly enhance the separation efficiency of aromatics and non-aromatics, but also significantly save energy consumption and reduce environmental pollution. The system utilizes plasma to selectively activate aromatic molecules, utilizes solvent extraction to separate aromatics and non-aromatics, and after recovering the solvent from the aromatic mixture, activates and purifies it using plasma-bleaching clay, followed by distillation, to obtain the target aromatics product. With the coordinated cooperation of various devices, the separation efficiency of aromatics and non-aromatics is significantly enhanced. The system is particularly suitable for processing components with similar boiling points (such as benzene and cyclohexane) and difficult raw materials such as heavy oil and coal tar. This system not only expands the source of raw materials, but also effectively improves the aromatics recovery rate and raw material utilization rate, providing an innovative technical solution for the petrochemical and coal chemical fields.

[0047] The operating process of the plasma-assisted aromatics extraction and separation system provided by the present invention can effectively process complex raw materials, improve the adaptability and utilization rate of raw materials, and ensure the efficiency and stability of the separation process; this process not only improves the recovery rate and purity of aromatics, but also significantly reduces the overall cost, thus having higher economy and market competitiveness, and has important industrial application value and promotion prospects in the field of aromatics separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0049] Figure 1 A schematic structural diagram of a plasma-assisted aromatics extraction and separation system provided in accordance with one embodiment of the present invention. DETAILED DESCRIPTION

[0050] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0051] According to a first aspect of the present invention, a plasma-assisted aromatics extraction and separation system is provided. Figure 1 According to the processing order of raw materials (such as catalytic reforming oil, coal tar, light oil and pyrolysis gasoline, etc.), it includes plasma activation device, extractive distillation tower, solvent recovery tower, plasma-white clay combined device and distillation tower:

[0052] The plasma activation device is used to selectively activate the raw materials to enhance the polarity of aromatics;

[0053] The extractive distillation tower is used to extract the activated raw materials with solvents to separate aromatic hydrocarbons from non-aromatic hydrocarbons;

[0054] The solvent recovery tower is used to separate the aromatic hydrocarbon mixture collected at the bottom of the extractive distillation tower to obtain aromatic hydrocarbons and recovered solvent;

[0055] The plasma-white clay combined device is used to activate and purify the separated aromatics;

[0056] The distillation tower is used to distill the purified aromatics to obtain aromatic products.

[0057] Since traditional aromatics separation methods rely on high temperature, high pressure or large amounts of chemical solvents, they result in high energy consumption and severe environmental pollution. The system of the present invention utilizes plasma activation technology at room temperature and pressure, which can greatly reduce energy consumption, while reducing dependence on chemical solvents, significantly reducing environmental pollution, and avoiding the damage to raw materials caused by high temperature and high pressure. The operating conditions are milder and safer.

[0058] In the present invention, through the deep integration of plasma technology and aromatics extraction process, with the coordinated cooperation of various devices, it is particularly suitable for the separation of aromatics from difficult raw materials such as heavy oil and coal tar, and realizes the efficient separation and distillation purification of aromatics (such as benzene, toluene, xylene and its derivatives) and non-aromatics (such as alkanes, cycloalkanes and their derivatives), which is beneficial to improving raw material utilization and energy efficiency, and is beneficial to reducing energy consumption and production costs. It can significantly improve the comprehensive economic benefits of aromatics separation and the sustainable development potential of the process, and provide strong support for building a green, low-carbon, efficient and safe petrochemical industrial system.

[0059] In a preferred embodiment, an extraction and feeding device can be provided before the plasma activation device. Figure 1 The extraction and feeding device is used to receive and pre-treat raw materials (such as catalytic reforming oil, pyrolysis gasoline, etc.) and transport them to the plasma activation device, which is conducive to uniform and stable transportation of the raw materials to the plasma activation device.

[0060] In the present invention, the plasma activation device can adopt dielectric barrier discharge (DBD), radio frequency plasma and / or microwave plasma. The plasma activation device uses plasma technology to efficiently activate the raw material, thereby significantly enhancing the polarity of the aromatic component and improving its separation characteristics from non-aromatic hydrocarbons. After activation, the raw material enters the extractive distillation tower.

[0061] The extractive distillation tower performs preliminary separation on the activated raw materials and separates aromatic hydrocarbons from non-aromatic hydrocarbons; a packing layer or a tower tray can be set in the extractive distillation tower to improve the mass transfer efficiency.

[0062] In a preferred embodiment, an extractive distillation column can also be provided in the system of the present invention. Figure 1 , to extract and distill the mixture of aromatic hydrocarbons and non-aromatic hydrocarbons collected at the top of the extractive distillation tower, and recover the aromatic hydrocarbons and return them to the plasma activation device.

[0063] It should be noted that the solvent recovery tower separates aromatic hydrocarbons from the solvent. In the solvent recovery tower, aromatic hydrocarbons are extracted from the top of the tower, and the solvent is recovered from the bottom of the tower and can be returned to the extractive distillation tower for recycling.

[0064] In a preferred embodiment, the plasma-clay combined device includes but is not limited to a plasma reaction zone for activating aromatic hydrocarbon molecules and a clay adsorption zone for removing polar impurities.

[0065] In the present invention, the plasma reaction zone may adopt dielectric barrier discharge (DBD), radio frequency plasma and / or microwave plasma.

[0066] The plasma-bleaching clay combined device activates and purifies the aromatic hydrocarbons separated from the solvent recovery tower by combining plasma activation with bleaching clay adsorption.

[0067] In a preferred embodiment, the distillation tower includes but is not limited to at least one of a benzene distillation tower (benzene tower), a toluene distillation tower (toluene tower) and a xylene distillation tower (xylene tower). Figure 1 , a packing layer or tray can be set in the distillation tower to improve the mass transfer efficiency.

[0068] It should be noted that the benzene distillation tower (benzene tower) distills the purified aromatics from the plasma-white clay combined unit to separate high-purity benzene; the toluene distillation tower (toluene tower) distills the remaining materials from the benzene distillation tower (benzene tower) to separate high-purity toluene; the xylene distillation tower (xylene tower) distills the remaining materials from the toluene distillation tower (toluene tower) to separate high-purity xylene.

[0069] In a preferred embodiment, a plasma assisted cracking unit may be provided after the distillation tower. Figure 1 The remaining materials after separation in the distillation tower (such as C9A heavy aromatics) enter the plasma-assisted cracking unit for dealkylation to generate light aromatics which are returned to the plasma activation unit.

[0070] In the present invention, the plasma-assisted cracking device may use dielectric barrier discharge (DBD), radio frequency plasma and / or microwave plasma.

[0071] In a preferred embodiment, a control module may also be provided in the system of the present invention to control the operating parameters of each device.

[0072] In the present invention, the control module includes but is not limited to at least one of a power regulation module, a solvent flow control module, a temperature control module and a pressure control module.

[0073] It should be noted that the power regulation module is used to control the plasma generation power and activation time; the solvent flow control module is used to adjust the solvent injection amount in the extractive distillation tower; the temperature control module is used to maintain the temperature of the extractive distillation tower and the distillation tower; the pressure control module is used to adjust the pressure of the extractive distillation tower and the distillation tower.

[0074] The efficiency and stability of the separation process are ensured through the full-process automation control module.

[0075] In summary, the system of the present invention applies plasma technology to the pretreatment and activation of aromatic extraction raw materials, the refining of aromatic mixed components, and the cracking and recycling of heavy aromatic components. With the coordinated cooperation of various devices, it can not only effectively process complex raw materials, improve the adaptability and utilization rate of raw materials, and significantly improve the separation efficiency of aromatics and non-aromatics and product purity, but also effectively reduce energy consumption and environmental pollution, significantly reduce the overall cost, and have higher economy and market competitiveness. It can be seen that the present invention provides a high-efficiency, energy-saving, and environmentally friendly technical solution for aromatic separation.

[0076] According to a second aspect of the present invention, there is provided a process for operating the system described in any one of the above items, comprising the following steps:

[0077] The raw materials are first selectively activated by a plasma activation device, and then separated into aromatics and non-aromatics by an extractive distillation tower. The solvent is then recovered by a solvent recovery tower. After that, they are activated and purified by a plasma-white clay combined device, and then distilled by a distillation tower to obtain aromatic products.

[0078] The operating process of the plasma-assisted aromatics extraction and separation system provided by the present invention can effectively process complex raw materials, improve the adaptability and utilization rate of raw materials, and ensure the efficiency and stability of the separation process; this process not only improves the recovery rate and purity of aromatics, but also significantly reduces the overall cost, thus having higher economy and market competitiveness, and has important industrial application value and promotion prospects in the field of aromatics separation.

[0079] In the present invention, a plasma activation device selectively activates the raw materials at normal temperature and pressure, thereby enhancing the polarity of aromatic hydrocarbon molecules and improving the separation efficiency of aromatic hydrocarbons from non-aromatic hydrocarbons.

[0080] In a preferred embodiment, the operating parameters of the plasma activation device are as follows:

[0081] The plasma power can be 1 kW to 10 kW (preferably 5 kW);

[0082] The gas atmosphere can be a mixture of argon and oxygen (volume ratio 9:1), and the flow rate can be 10L / min;

[0083] The activation time may be 1 to 5 minutes (preferably 3 minutes).

[0084] After the raw materials enter the plasma activation device, under the action of high-energy plasma, the aromatic molecules are selectively activated and the polarity is significantly enhanced, providing high-polarity raw materials for subsequent extraction and separation.

[0085] In the present invention, the extractive distillation column separates aromatic hydrocarbons from non-aromatic hydrocarbons by solvent extraction.

[0086] In a preferred embodiment, the operating parameters of the extractive distillation column are as follows:

[0087] The extraction solvent can be sulfolane or sulfolane compound alcohol ether;

[0088] The mass ratio of the extraction solvent to the raw material can be 1:5 to 1:10 (preferably 1:8);

[0089] The extraction temperature may be 80° C. to 200° C. (preferably 120° C.), and the extraction pressure may be 0.1 MPa to 1 MPa (preferably 0.5 MPa).

[0090] In the extractive distillation tower, the selective solubility of the extraction solvent is utilized, and with the coordinated cooperation of various operating parameters, aromatic hydrocarbons and non-aromatic hydrocarbons can be efficiently separated. Aromatic hydrocarbons enter the solvent phase, and non-aromatic hydrocarbons are discharged from the top of the tower.

[0091] In the present invention, the extractive distillation tower extracts and distills the mixture of aromatic hydrocarbons and non-aromatic hydrocarbons collected from the top of the extractive distillation tower to recover the aromatic hydrocarbons.

[0092] In a preferred embodiment, the operating parameters of the extractive distillation column are as follows:

[0093] The extraction temperature may be 100° C. to 150° C. (preferably 130° C.), and the extraction pressure may be 0.1 MPa to 0.8 MPa (preferably 0.3 MPa).

[0094] In the extractive distillation tower, aromatic hydrocarbons and non-aromatic hydrocarbons are separated by extractive distillation, non-aromatic hydrocarbons are extracted from the top of the tower, and aromatic hydrocarbons are recovered from the bottom of the tower and can be returned to the plasma activation device.

[0095] In the present invention, the solvent recovery tower separates the mixture of aromatic hydrocarbons and solvent collected at the bottom of the extractive distillation tower, thereby recovering the aromatic hydrocarbons and realizing the recycling of the solvent.

[0096] In a preferred embodiment, the operating parameters of the solvent recovery tower are as follows:

[0097] The recovery temperature may be 150° C. to 200° C. (preferably 180° C.), and the recovery pressure may be 0.1 MPa to 0.5 MPa (preferably 0.3 MPa).

[0098] In the solvent recovery tower, aromatics are extracted from the top of the tower, and the solvent is recovered from the bottom of the tower and can be returned to the extraction distillation tower for recycling, thereby realizing the recycling of the solvent.

[0099] In the present invention, the plasma-clay combined device can further activate and purify aromatic hydrocarbons, thereby facilitating the removal of residual impurities.

[0100] In a preferred embodiment, the operating parameters of the plasma-clay combined device are as follows:

[0101] The plasma power can be 1kW to 5kW (preferably 3kW);

[0102] The adsorption temperature of the clay can be 80° C. to 150° C. (preferably 120° C.), and the adsorption time can be 5 minutes to 15 minutes (preferably 10 minutes).

[0103] In the plasma-bleaching clay combined device, aromatic hydrocarbons are first activated by plasma to further expand the polarity difference between aromatic hydrocarbons and non-aromatic hydrocarbons, and then adsorbed by bleaching clay to remove residual polar impurities, effectively ensuring the high purity of aromatic hydrocarbons.

[0104] In a preferred embodiment, the temperature of the benzene distillation tower in the distillation tower can be 110°C to 120°C, and the pressure can be 0.1MPa to 0.5MPa; the temperature of the toluene distillation tower in the distillation tower can be 135°C to 145°C, and the pressure can be 0.1MPa to 0.5MPa; the temperature of the xylene distillation tower in the distillation tower can be 140°C to 150°C, and the pressure can be 0.1MPa to 0.5MPa.

[0105] In a preferred embodiment, the operating parameters of the plasma assisted cracking unit are as follows:

[0106] The cracking temperature can be 400°C to 600°C (preferably 500°C), and the cracking pressure can be 0.1MPa to 0.5MPa (preferably 0.3MPa);

[0107] The plasma power may be 5 kW to 10 kW (preferably 8 kW).

[0108] The plasma-assisted cracking unit conducts a targeted dealkylation reaction on the heavy aromatics remaining after distillation to generate light aromatics, which can be returned to the plasma activation unit and then separated through the extractive distillation tower, thereby facilitating the efficient utilization of resources.

[0109] A typical operation process of a plasma-assisted aromatics extraction and separation system includes the following steps:

[0110] First, the raw materials (such as heavy oil and coal tar) are transported to the plasma activation device through the extraction and feeding device. The aromatic molecules are selectively activated under normal temperature and pressure conditions, significantly enhancing the polarity of the aromatics to obtain the activated raw materials.

[0111] After that, the activated raw materials are transported to the extractive distillation tower, where aromatics and non-aromatics are efficiently separated under the action of the extraction solvent (sulfolane or sulfolane compounded alcohol ether);

[0112] The solvent-poor material at the top of the extractive distillation tower is extracted through an extractive distillation tower to recover residual aromatics, which are then returned to the plasma activation device for efficient resource utilization.

[0113] The mixture of aromatic hydrocarbons and solvent at the bottom of the extractive distillation tower is transported to a solvent recovery tower to separate the aromatic hydrocarbons and solvent, and the aromatic hydrocarbons and solvent are separated and the solvent is recycled;

[0114] Then, the separated aromatics are transported to a plasma-white clay combined device for deep activation and purification. The purified aromatics are then transported to a distillation tower for distillation to separate benzene, toluene, and xylene to obtain high-purity benzene, toluene, and xylene products.

[0115] Finally, the heavy aromatics remaining after distillation are subjected to a directional dealkylation reaction in a plasma-assisted cracking unit to be converted into light aromatics, which are then returned to the plasma activation unit for efficient resource utilization.

[0116] The present invention is based on the operation process of the plasma-assisted aromatics extraction and separation system, which has achieved the following beneficial effects:

[0117] (1) Significantly improve separation efficiency: By applying plasma technology in the raw material pretreatment and aromatic distillation stages, aromatic molecules are selectively activated and their polarity is enhanced, significantly improving the separation efficiency of aromatics and non-aromatics. Experiments have shown that the recovery rate of aromatics has increased by 15% to 20%, and the product purity has reached more than 99%;

[0118] (2) Reduce energy consumption: Plasma technology has high energy utilization rate. Combined with solvent recycling and optimized process parameters, the overall energy consumption is significantly reduced compared with traditional processes;

[0119] (3) Significant environmental benefits: Through the plasma-assisted cracking unit, heavy aromatics are converted into light aromatics, achieving efficient resource utilization and reducing waste emissions; at the same time, the recycling of solvents reduces waste liquid treatment costs and reduces environmental pollution;

[0120] (4) Wide range of applications: This process is particularly suitable for the separation of aromatics from difficult raw materials such as heavy oil and coal tar, thus expanding the source of raw materials;

[0121] (5) High value-added products: Through distillation and dealkylation reactions, high-purity light aromatics such as benzene, toluene and xylene are obtained, which increases the economic value of the products and the yield of light aromatics.

[0122] The present invention is further described below by way of examples. Unless otherwise specified, the materials in the examples were prepared according to existing methods or directly purchased from the market.

[0123] Example 1

[0124] A plasma-assisted aromatics extraction and separation system includes, in order of raw material processing, a plasma activation device, an extractive distillation tower, a solvent recovery tower, a plasma-clay combined device, and a distillation tower:

[0125] The plasma activation device uses dielectric barrier discharge (DBD), radio frequency plasma and / or microwave plasma to selectively activate the raw materials to enhance the polarity of aromatic hydrocarbons and form activated raw materials;

[0126] The activated raw materials enter the extractive distillation tower, which extracts the activated raw materials with solvent to separate aromatic hydrocarbons and non-aromatic hydrocarbons;

[0127] The solvent recovery tower separates the aromatic hydrocarbon mixture collected at the bottom of the extractive distillation tower to obtain aromatic hydrocarbons and recovered solvent;

[0128] The separated aromatic hydrocarbons enter the plasma-clay combined device, which includes a plasma reaction zone for activating aromatic hydrocarbon molecules and a clay adsorption zone for removing polar impurities, to activate and purify the separated aromatic hydrocarbons.

[0129] The distillation tower distills the purified aromatic hydrocarbons from the plasma-white clay combined device. The distillation tower includes a benzene distillation tower, a toluene distillation tower and a xylene distillation tower. The purified aromatic hydrocarbons are distilled to obtain benzene, toluene and xylene products.

[0130] The benzene distillation tower distills the purified aromatics from the plasma-white clay combined unit to separate high-purity benzene; the toluene distillation tower distills the remaining materials from the benzene distillation tower to separate high-purity toluene; the xylene distillation tower distills the remaining materials from the toluene distillation tower to separate high-purity xylene.

[0131] Example 2

[0132] This embodiment provides a plasma-assisted aromatic hydrocarbon extraction and separation system, which differs from Example 1 only in that an extraction and feeding device is provided before the plasma activation device;

[0133] The extraction and feeding device is used to receive and pre-treat the raw materials and transport them to the plasma activation device, so that the raw materials can be transported to the plasma activation device evenly and stably;

[0134] The rest are the same as in Example 1.

[0135] Example 3

[0136] This embodiment provides a plasma-assisted aromatic hydrocarbon extraction and separation system. The only difference from Example 2 is that the system further includes an extractive distillation tower to extract and distill the mixture of aromatic hydrocarbons and non-aromatic hydrocarbons collected from the top of the extractive distillation tower, and the recovered aromatic hydrocarbons are returned to the plasma activation device.

[0137] The rest are the same as in Example 1.

[0138] Example 4

[0139] This embodiment provides a plasma-assisted aromatics extraction and separation system. The only difference from Example 3 is that a plasma-assisted cracking unit is provided after the distillation column. The plasma-assisted cracking unit uses dielectric barrier discharge (DBD), radio frequency plasma and / or microwave plasma.

[0140] The plasma-assisted cracking unit conducts a directional dealkylation reaction on the heavy aromatics remaining after distillation to generate light aromatics which are returned to the plasma activation unit.

[0141] The rest are the same as in Example 1.

[0142] Example 5

[0143] This embodiment provides a plasma-assisted aromatics extraction and separation system. The only difference from Example 4 is that the system is further provided with a control module to control the operating parameters of each device.

[0144] The control module includes a power regulation module, a solvent flow control module, a temperature control module and a pressure control module;

[0145] The power regulation module is used to control the plasma generation power and activation time;

[0146] The solvent flow control module is used to adjust the solvent injection amount in the extractive distillation column;

[0147] The temperature control module is used to maintain the temperature of the extractive distillation column and the distillation column;

[0148] The pressure control module is used to adjust the pressure of the extractive distillation column and the distillation column;

[0149] The rest are the same as in Example 1.

[0150] Example 6

[0151] This embodiment is an operation process of the plasma-assisted aromatics extraction and separation system of Example 5, comprising the following steps:

[0152] First, heavy oil (with an aromatic content of approximately 40% and a non-aromatic content of approximately 60%) was transported via an extraction feed device to a plasma activation device. Aromatic molecules were selectively activated at room temperature and pressure. The plasma power was 5 kW, the gas atmosphere was a mixture of argon and oxygen (with a volume ratio of 9:1), the flow rate of the mixed gas was 10 L / min, and the selective activation time was 3 minutes. This significantly enhanced the polarity of the aromatics and produced the activated raw material.

[0153] Afterwards, the activated raw material is transported to an extractive distillation tower, using sulfolane as the extraction solvent. The mass ratio of the solvent to the raw material is 1:8, the extraction temperature is 120°C, and the extraction pressure is 0.5MPa. In the extractive distillation tower, aromatics and non-aromatics are efficiently separated, with aromatics entering the solvent phase and non-aromatics discharged from the top of the tower.

[0154] The lean solvent material at the top of the extractive distillation tower is extracted by an extractive distillation tower at an extraction temperature of 130°C and an extraction pressure of 0.3 MPa. The extractive distillation tower recovers the residual aromatics in the lean solvent and returns it to the plasma activation device;

[0155] The mixture of aromatic hydrocarbons and solvent at the bottom of the extractive distillation tower is transported to the solvent recovery tower to separate the aromatic hydrocarbons and solvent. The temperature of the solvent recovery tower is 180°C and the pressure is 0.3MPa. The aromatic hydrocarbons and solvent are separated by distillation. The aromatic hydrocarbons are extracted from the top of the tower and the solvent is recovered from the bottom of the tower and recycled.

[0156] Then, the separated aromatics are transported to a plasma-bleaching clay combined device for deep activation and purification. The plasma power is 3 kW, the bleaching clay adsorption temperature is 120° C., and the adsorption time is 10 minutes. Through plasma activation and bleaching clay adsorption, polar impurities in the aromatics are further removed. The purified aromatics are transported to a distillation tower for distillation. The benzene distillation temperature is 115° C., the toluene distillation temperature is 140° C., and the xylene distillation temperature is 145° C. The distillation pressure is 0.3 MPa. Benzene, toluene, and xylene are separated to obtain high-purity benzene, toluene, and xylene products, i.e., aromatics products.

[0157] Finally, the heavy aromatics remaining after distillation are subjected to a directional dealkylation reaction in a plasma-assisted cracking unit with a cracking temperature of 500°C, a cracking pressure of 0.3 MPa, and a plasma power of 8 kW. The heavy aromatics are converted into light aromatics and returned to the plasma activation unit.

[0158] In this embodiment, the aromatic product recovery rate is 97%, the aromatic product purity is 99.6%, the process energy consumption is reduced by 22%, and the solvent recovery rate is 98.5%.

[0159] Example 7

[0160] This embodiment is an operation process of the plasma-assisted aromatics extraction and separation system of Example 5, comprising the following steps:

[0161] First, coal tar (with an aromatic content of approximately 35% and a non-aromatic content of approximately 65%) was transported via an extraction feed device to a plasma activation device. Aromatic molecules were selectively activated at room temperature and pressure. The plasma power was 3 kW, the gas atmosphere was a mixture of argon and oxygen (with a volume ratio of 9:1), the flow rate of the mixed gas was 10 L / min, and the selective activation time was 5 minutes. This significantly enhanced the polarity of the aromatics and produced the activated raw material.

[0162] Afterwards, the activated raw materials are transported to an extractive distillation tower, using sulfolane compound alcohol ether as the extraction solvent. The mass ratio of solvent to raw materials is 1:10, the extraction temperature is 200°C, and the extraction pressure is 1MPa. In the extractive distillation tower, aromatics and non-aromatics are efficiently separated, with aromatics entering the solvent phase and non-aromatics discharged from the top of the tower.

[0163] The lean solvent material at the top of the extractive distillation tower is extracted by an extractive distillation tower at an extraction temperature of 150°C and an extraction pressure of 0.5 MPa. The extractive distillation tower recovers the residual aromatics in the lean solvent and returns it to the plasma activation device;

[0164] The mixture of aromatic hydrocarbons and solvent at the bottom of the extractive distillation tower is transported to the solvent recovery tower to separate the aromatic hydrocarbons and solvent. The temperature of the solvent recovery tower is 200°C and the pressure is 0.5MPa. The aromatic hydrocarbons and solvent are separated by distillation. The aromatic hydrocarbons are extracted from the top of the tower and the solvent is recovered from the bottom of the tower and recycled.

[0165] Then, the separated aromatics are transported to a plasma-clay combined device for deep activation and purification. The plasma power is 2.5 kW, the clay adsorption temperature is 150° C., and the adsorption time is 12 minutes. Polar impurities in the aromatics are further removed through plasma activation and clay adsorption. The purified aromatics are transported to a distillation tower for distillation. The benzene distillation temperature is 120° C., the toluene distillation temperature is 145° C., and the xylene distillation temperature is 150° C. The distillation pressure is 0.5 MPa. Benzene, toluene, and xylene are separated to obtain high-purity benzene, toluene, and xylene products, i.e., aromatics products.

[0166] Finally, the heavy aromatics remaining after distillation are subjected to a directional dealkylation reaction in a plasma-assisted cracking unit with a cracking temperature of 600°C, a cracking pressure of 0.5 MPa, and a plasma power of 10 kW. The heavy aromatics are converted into light aromatics and returned to the plasma activation unit.

[0167] In this embodiment, the aromatic product recovery rate is 94%, the aromatic product purity is 99.3%, the process energy consumption is reduced by 18%, and the solvent recovery rate is 97.5%.

[0168] Example 8

[0169] This embodiment is an operation process of the plasma-assisted aromatics extraction and separation system of Example 5, comprising the following steps:

[0170] First, light oil (with an aromatic content of approximately 50% and a non-aromatic content of approximately 50%) was transported via an extraction feed device to a plasma activation device. Aromatic molecules were selectively activated at room temperature and pressure. The plasma power was 4 kW, the gas atmosphere was a mixture of argon and oxygen (with a volume ratio of 9:1), the flow rate of the mixed gas was 10 L / min, and the selective activation time was 4 minutes. This significantly enhanced the polarity of the aromatics and produced the activated raw material.

[0171] Afterwards, the activated raw material is transported to an extractive distillation tower, using sulfolane as the extraction solvent. The mass ratio of the solvent to the raw material is 1:6, the extraction temperature is 100°C, and the extraction pressure is 0.4MPa. In the extractive distillation tower, aromatics and non-aromatics are efficiently separated, with aromatics entering the solvent phase and non-aromatics discharged from the top of the tower.

[0172] The lean solvent material at the top of the extractive distillation tower is extracted by an extractive distillation tower at an extraction temperature of 120°C and an extraction pressure of 0.2 MPa. The extractive distillation tower recovers the residual aromatics in the lean solvent and returns it to the plasma activation device;

[0173] The mixture of aromatic hydrocarbons and solvent at the bottom of the extractive distillation tower is transported to the solvent recovery tower to separate the aromatic hydrocarbons and solvent. The temperature of the solvent recovery tower is 160°C and the pressure is 0.2MPa. The aromatic hydrocarbons and solvent are separated by distillation. The aromatic hydrocarbons are extracted from the top of the tower and the solvent is recovered from the bottom of the tower and recycled.

[0174] Then, the separated aromatics are transported to a plasma-bleaching clay combined device for deep activation and purification. The plasma power is 2 kW, the bleaching clay adsorption temperature is 100° C., and the adsorption time is 8 minutes. Through plasma activation and bleaching clay adsorption, polar impurities in the aromatics are further removed. The purified aromatics are transported to a distillation tower for distillation. The benzene distillation temperature is 110° C., the toluene distillation temperature is 135° C., and the xylene distillation temperature is 140° C. The distillation pressure is 0.25 MPa. Benzene, toluene, and xylene are separated to obtain high-purity benzene, toluene, and xylene products, i.e., aromatics products.

[0175] Finally, the heavy aromatics remaining after distillation are subjected to a directional dealkylation reaction in a plasma-assisted cracking unit at a cracking temperature of 450°C, a cracking pressure of 0.2 MPa, and a plasma power of 6 kW. The heavy aromatics are converted into light aromatics and returned to the plasma activation unit.

[0176] In this embodiment, the aromatic product recovery rate is 96%, the aromatic product purity is 99.4%, the process energy consumption is reduced by 20%, and the solvent recovery rate is 98%.

[0177] Example 9

[0178] This embodiment is an operation process of the plasma-assisted aromatics extraction and separation system of Example 5, comprising the following steps:

[0179] First, pyrolysis gasoline (with an aromatic content of approximately 45% and a non-aromatic content of approximately 55%) was transported via an extraction feed device to a plasma activation device. Aromatic molecules were selectively activated at room temperature and pressure. The plasma power was 4.5 kW, the gas atmosphere was a mixture of argon and oxygen (with a volume ratio of 9:1), the flow rate of the mixed gas was 10 L / min, and the selective activation time was 4.5 minutes. This significantly enhanced the polarity of the aromatics, resulting in the activated raw material.

[0180] Afterwards, the activated raw materials are transported to an extractive distillation tower, using sulfolane compound alcohol ether as the extraction solvent. The mass ratio of solvent to raw materials is 1:7, the extraction temperature is 150°C, and the extraction pressure is 0.6MPa. In the extractive distillation tower, aromatics and non-aromatics are efficiently separated, with aromatics entering the solvent phase and non-aromatics discharged from the top of the tower.

[0181] The lean solvent material at the top of the extractive distillation tower is extracted by an extractive distillation tower at an extraction temperature of 140°C and an extraction pressure of 0.4 MPa. The extractive distillation tower recovers the residual aromatics in the lean solvent and returns it to the plasma activation device;

[0182] The mixture of aromatic hydrocarbons and solvent at the bottom of the extractive distillation tower is transported to the solvent recovery tower to separate the aromatic hydrocarbons and solvent. The temperature of the solvent recovery tower is 190°C and the pressure is 0.4MPa. The aromatic hydrocarbons and solvent are separated by distillation. The aromatic hydrocarbons are extracted from the top of the tower and the solvent is recovered from the bottom of the tower and recycled.

[0183] Then, the separated aromatics are transported to a plasma-bleaching clay combined device for deep activation and purification. The plasma power is 3.5 kW, the bleaching clay adsorption temperature is 140° C., and the adsorption time is 10 minutes. Polar impurities in the aromatics are further removed through plasma activation and bleaching clay adsorption. The purified aromatics are transported to a distillation tower for distillation. The benzene distillation temperature is 115° C., the toluene distillation temperature is 145° C., and the xylene distillation temperature is 150° C. The distillation pressure is 0.4 MPa. Benzene, toluene, and xylene are separated to obtain high-purity benzene, toluene, and xylene products, i.e., aromatics products.

[0184] Finally, the heavy aromatics remaining after distillation are subjected to a directional dealkylation reaction in a plasma-assisted cracking unit with a cracking temperature of 550°C, a cracking pressure of 0.4 MPa, and a plasma power of 9 kW. The heavy aromatics are converted into light aromatics and returned to the plasma activation unit.

[0185] In this embodiment, the aromatic product recovery rate is 95%, the aromatic product purity is 99.5%, the process energy consumption is reduced by 19%, and the solvent recovery rate is 98.2%.

[0186] Comparative Example 1

[0187] This comparative example provides an aromatic hydrocarbon extraction and separation system, which differs from Example 1 only in that no plasma activation device is provided in this comparative example;

[0188] The rest are the same as in Example 1.

[0189] Compared with Example 1, the system of this comparative example cannot achieve efficient activation of aromatics, resulting in a significant decrease in the recovery rate and purity of the aromatics product.

[0190] Comparative Example 2

[0191] This comparative example provides an aromatic hydrocarbon extraction and separation system, which differs from Example 1 only in that no plasma activation device is provided in this comparative example;

[0192] At the same time, in this comparative example, the plasma-clay combined device was replaced by a clay device (ordinary clay tower);

[0193] The rest are the same as in Example 1.

[0194] Compared with Example 1, the system of this comparative example cannot achieve efficient activation and deep purification of aromatics, resulting in a significant decrease in the recovery rate and purity of the aromatics product.

[0195] Comparative Example 3

[0196] This embodiment is the operation process of the aromatics extraction and separation system of Comparative Example 2, comprising the following steps:

[0197] First, heavy oil (aromatic content of about 40% and non-aromatic content of about 60%) is transported to an extractive distillation tower. Sulfolane is used as the extraction solvent. The mass ratio of solvent to raw material is 1:8, the extraction temperature is 120°C, and the extraction pressure is 0.5MPa. In the extractive distillation tower, aromatics and non-aromatics are separated. Aromatics enter the solvent phase, while non-aromatics are discharged from the top of the tower.

[0198] The lean solvent material at the top of the extractive distillation tower is extracted by an extractive distillation tower at an extraction temperature of 130°C and an extraction pressure of 0.3 MPa. The extractive distillation tower recovers residual aromatics in the lean solvent;

[0199] The mixture of aromatic hydrocarbons and solvent at the bottom of the extractive distillation tower is transported to the solvent recovery tower to separate the aromatic hydrocarbons and solvent. The temperature of the solvent recovery tower is 180°C and the pressure is 0.3MPa. The aromatic hydrocarbons and solvent are separated by distillation. The aromatic hydrocarbons are extracted from the top of the tower and the solvent is recovered from the bottom of the tower and recycled.

[0200] Then, the separated aromatics are transported to a kaolin device (ordinary kaolin tower) for purification. The kaolin adsorption temperature is 120°C and the adsorption time is 10 minutes to remove polar impurities in the aromatics. The purified aromatics are transported to a distillation tower for distillation. The benzene distillation temperature is 115°C, the toluene distillation temperature is 140°C, the xylene distillation temperature is 145°C, and the distillation pressure is 0.3 MPa. Benzene, toluene and xylene are separated to obtain high-purity benzene, toluene and xylene products, i.e., aromatics products.

[0201] In this embodiment, the aromatic product recovery rate is 85%, the aromatic product purity is 98.5%, the process energy consumption is relatively high, and the solvent recovery rate is 96%.

[0202] Comparative Example 4

[0203] This embodiment is the operation process of the aromatics extraction and separation system of Comparative Example 2, comprising the following steps:

[0204] First, coal tar (aromatic content of about 35% and non-aromatic content of about 65%) is transported to an extractive distillation tower. Sulfolane compound alcohol ether is used as the extraction solvent. The mass ratio of solvent to raw material is 1:10, the extraction temperature is 200°C, and the extraction pressure is 1MPa. In the extractive distillation tower, aromatics and non-aromatics are separated. Aromatics enter the solvent phase, while non-aromatics are discharged from the top of the tower.

[0205] The lean solvent material at the top of the extractive distillation tower is extracted by an extractive distillation tower at an extraction temperature of 150°C and an extraction pressure of 0.5 MPa. The extractive distillation tower recovers residual aromatics in the lean solvent;

[0206] The mixture of aromatic hydrocarbons and solvent at the bottom of the extractive distillation tower is transported to the solvent recovery tower to separate the aromatic hydrocarbons and solvent. The temperature of the solvent recovery tower is 200°C and the pressure is 0.5MPa. The aromatic hydrocarbons and solvent are separated by distillation. The aromatic hydrocarbons are extracted from the top of the tower and the solvent is recovered from the bottom of the tower and recycled.

[0207] Then, the separated aromatics are transported to a kaolin device (ordinary kaolin tower) for purification. The kaolin adsorption temperature is 120°C and the adsorption time is 10 minutes to remove polar impurities in the aromatics. The purified aromatics are transported to a distillation tower for distillation. The benzene distillation temperature is 120°C, the toluene distillation temperature is 145°C, the xylene distillation temperature is 150°C, and the distillation pressure is 0.5 MPa. Benzene, toluene and xylene are separated to obtain high-purity benzene, toluene and xylene products, i.e., aromatics products.

[0208] In this embodiment, the aromatic product recovery rate is 78%, the aromatic product purity is 97.8%, the process energy consumption is relatively high, and the solvent recovery rate is 95.5%.

[0209] Comparative Example 5

[0210] This embodiment is the operation process of the aromatics extraction and separation system of Comparative Example 2, comprising the following steps:

[0211] First, light oil (aromatic content of about 50% and non-aromatic content of about 50%) is transported to an extractive distillation tower. Sulfolane is used as the extraction solvent. The mass ratio of solvent to raw material is 1:6. The extraction temperature is 100°C and the extraction pressure is 0.4MPa. In the extractive distillation tower, aromatics and non-aromatics are separated. Aromatics enter the solvent phase, while non-aromatics are discharged from the top of the tower.

[0212] The lean solvent material at the top of the extractive distillation tower is extracted by an extractive distillation tower at an extraction temperature of 120°C and an extraction pressure of 0.2 MPa. The extractive distillation tower recovers residual aromatics in the lean solvent;

[0213] The mixture of aromatic hydrocarbons and solvent at the bottom of the extractive distillation tower is transported to the solvent recovery tower to separate the aromatic hydrocarbons and solvent. The temperature of the solvent recovery tower is 160°C and the pressure is 0.2MPa. The aromatic hydrocarbons and solvent are separated by distillation. The aromatic hydrocarbons are extracted from the top of the tower and the solvent is recovered from the bottom of the tower and recycled.

[0214] Then, the separated aromatics are transported to a kaolin device (ordinary kaolin tower) for purification. The kaolin adsorption temperature is 150°C and the adsorption time is 12 minutes to remove polar impurities in the aromatics. The purified aromatics are transported to a distillation tower for distillation. The benzene distillation temperature is 110°C, the toluene distillation temperature is 135°C, the xylene distillation temperature is 140°C, and the distillation pressure is 0.25 MPa. Benzene, toluene and xylene are separated to obtain high-purity benzene, toluene and xylene products, i.e., aromatics products.

[0215] In this embodiment, the aromatic product recovery rate is 82%, the aromatic product purity is 98.2%, the process energy consumption is relatively high, and the solvent recovery rate is 95.8%.

[0216] Comparative Example 6

[0217] This embodiment is the operation process of the aromatics extraction and separation system of Comparative Example 2, comprising the following steps:

[0218] First, pyrolysis gasoline (aromatic content of about 45% and non-aromatic content of about 55%) is transported to an extractive distillation tower. Sulfolane compound alcohol ether is used as the extraction solvent. The mass ratio of solvent to raw material is 1:7, the extraction temperature is 150°C, and the extraction pressure is 0.6MPa. In the extractive distillation tower, aromatics and non-aromatics are separated. Aromatics enter the solvent phase, while non-aromatics are discharged from the top of the tower.

[0219] The lean solvent material at the top of the extractive distillation tower is extracted by an extractive distillation tower at an extraction temperature of 140°C and an extraction pressure of 0.4 MPa. The extractive distillation tower recovers residual aromatics in the lean solvent;

[0220] The mixture of aromatic hydrocarbons and solvent at the bottom of the extractive distillation tower is transported to the solvent recovery tower to separate the aromatic hydrocarbons and solvent. The temperature of the solvent recovery tower is 190°C and the pressure is 0.4MPa. The aromatic hydrocarbons and solvent are separated by distillation. The aromatic hydrocarbons are extracted from the top of the tower and the solvent is recovered from the bottom of the tower and recycled.

[0221] Then, the separated aromatics are transported to a kaolin device (ordinary kaolin tower) for purification. The kaolin adsorption temperature is 140°C and the adsorption time is 10 minutes to remove polar impurities in the aromatics. The purified aromatics are transported to a distillation tower for distillation. The benzene distillation temperature is 120°C, the toluene distillation temperature is 145°C, the xylene distillation temperature is 150°C, and the distillation pressure is 0.4 MPa. Benzene, toluene and xylene are separated to obtain high-purity benzene, toluene and xylene products, i.e., aromatics products.

[0222] In this embodiment, the aromatic product recovery rate is 80%, the aromatic product purity is 98%, the process energy consumption is relatively high, and the solvent recovery rate is 95%.

[0223] In summary, the system of the present invention uses plasma to selectively activate aromatic hydrocarbon molecules, uses solvent extraction to separate aromatic hydrocarbons and non-aromatic hydrocarbons, recovers the solvent from the aromatic hydrocarbon mixture, and then activates and purifies it through plasma-bleaching clay, and distills it to obtain the target aromatic hydrocarbon product. With the coordinated cooperation of various devices, the separation efficiency of aromatic hydrocarbons and non-aromatic hydrocarbons is significantly improved. It is particularly suitable for the treatment of components with similar boiling points (such as benzene and cyclohexane) and difficult raw materials such as heavy oil and coal tar. It not only expands the source of raw materials, but also effectively improves the aromatic hydrocarbon recovery rate and raw material utilization rate.

[0224] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A plasma-assisted aromatics extraction and separation system, characterized in that: In order of raw material processing, it includes plasma activation device, extractive distillation tower, solvent recovery tower, plasma-white clay combined device and distillation tower: The plasma activation device is used to selectively activate the raw materials to enhance the polarity of aromatic hydrocarbons; The extractive distillation tower is used to perform solvent extraction on the activated raw materials to separate aromatic hydrocarbons and non-aromatic hydrocarbons; The solvent recovery tower is used to separate the aromatic hydrocarbon mixture collected at the bottom of the extractive distillation tower to obtain aromatic hydrocarbons and recovered solvent; The plasma-white clay combined device is used to activate and purify the separated aromatic hydrocarbons; The distillation tower is used to distill the purified aromatics to obtain aromatic products.

2. The system according to claim 1, wherein: An extraction and feeding device is provided before the plasma activation device to ensure that the raw materials are evenly and stably transported to the plasma activation device; Preferably, the plasma activation device adopts dielectric barrier discharge, radio frequency plasma and / or microwave plasma.

3. The system according to claim 2, characterized in that The system is further provided with an extractive distillation tower to extractively distill the mixture of aromatic hydrocarbons and non-aromatic hydrocarbons collected at the top of the extractive distillation tower, and recover the aromatic hydrocarbons therein and return them to the plasma activation device; Preferably, the system is further provided with a control module to control the operating parameters of each device; Preferably, the control module includes at least one of a power regulation module, a solvent flow control module, a temperature control module and a pressure control module; Preferably, the power regulation module is used to control the plasma generation power and activation time; Preferably, the solvent flow control module is used to adjust the solvent injection rate in the extractive distillation column; Preferably, the temperature control module is used to maintain the temperature of the extractive distillation column and the rectifying column; Preferably, the pressure control module is used to adjust the pressure of the extractive distillation column and the rectifying column.

4. The system according to claim 1, wherein: The plasma-clay combined device includes a plasma reaction zone for activating aromatic hydrocarbon molecules and a clay adsorption zone for removing polar impurities; Preferably, the distillation tower includes at least one of a benzene distillation tower, a toluene distillation tower and a xylene distillation tower.

5. The system according to any one of claims 1 to 4, characterized in that: A plasma-assisted cracking unit is provided after the distillation tower to dealkylate heavy aromatics to generate light aromatics which are returned to the plasma activation unit; Preferably, the plasma-assisted cracking device adopts dielectric barrier discharge, radio frequency plasma and / or microwave plasma.

6. An operating process of the system according to any one of claims 1 to 5, characterized in that: The following steps are involved: The raw materials are first selectively activated by a plasma activation device, and then separated into aromatics and non-aromatics by an extractive distillation tower. The solvent is then recovered by a solvent recovery tower. After that, they are activated and purified by a plasma-white clay combined device, and then distilled by a distillation tower to obtain aromatic products.

7. The operating process according to claim 6, characterized in that: The plasma power of the plasma activation device is 1kW to 10kW; Preferably, the gas atmosphere of the plasma activation device is a mixture of argon and oxygen; Preferably, the volume ratio of argon to oxygen in the mixed gas is 9:1; Preferably, the flow rate of the mixed gas is 10 L / min; Preferably, the selective activation time is 1 minute to 5 minutes.

8. The operation process according to claim 6, characterized in that: The extraction solvent used in the extractive distillation column is sulfolane or sulfolane compound alcohol ether; Preferably, the mass ratio of the extraction solvent to the raw material is 1:5 to 1:10; Preferably, the extraction temperature of the extractive distillation tower is 80° C. to 200° C., and the extraction pressure is 0.1 MPa to 1 MPa.

9. The operation process according to claim 6, characterized in that: The temperature of the benzene distillation tower in the distillation tower is 110°C to 120°C, and the pressure is 0.1MPa to 0.5MPa; Preferably, the temperature of the toluene distillation tower in the distillation tower is 135° C. to 145° C., and the pressure is 0.1 MPa to 0.5 MPa; Preferably, the temperature of the xylene distillation tower in the distillation tower is 140° C. to 150° C., and the pressure is 0.1 MPa to 0.5 MPa.

10. The operation process according to any one of claims 6 to 9, characterized in that: The operation process further comprises the following steps: The mixture of aromatic hydrocarbons and non-aromatic hydrocarbons collected from the top of the extractive distillation tower is subjected to extractive distillation in an extractive distillation tower, and the aromatic hydrocarbons therein are recovered and returned to the plasma activation device; The heavy aromatics obtained after distillation are subjected to a directional dealkylation reaction in a plasma-assisted cracking unit to generate light aromatics which are returned to the plasma activation unit.

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