An extraction device and method

Abstract

The application relates to the field of petroleum chemical industry, and particularly discloses an extraction device and an extraction method. The extraction device comprises an extraction tower. A plurality of extraction fillers are arranged in the extraction tower to form a plurality of extraction zones in the extraction tower, and the plurality of extraction fillers divide the extraction tower into a plurality of containing zones. The extraction tower is provided with a plurality of solvent inlets, the plurality of solvent inlets are arranged in different containing zones, the extraction tower is provided with a raw material inlet, the raw material inlet is located in the containing zone close to the bottom of the extraction tower, the top of the extraction tower is provided with a raffinate outlet, and the bottom is provided with a extract outlet. The solvent is injected through the plurality of solvent inlets, the purpose of reducing the solvent consumption and reducing the extraction energy consumption is achieved, the injection temperature and flow of the solvent are controlled, the temperature gradient in the tower is controlled, and the extraction effect of the material is further improved. The extraction method has the advantages of high extraction efficiency, flexible and controllable operation, improved product yield, reduced extraction solvent consumption and reduced energy consumption.

Description

Technical Field

[0001] This application relates to the field of petrochemicals, and more specifically, to an extraction apparatus and extraction method. Background Technology

[0002] Furfural extraction technology, as a commonly used heavy oil processing technology, typically uses furfural as a solvent. Based on the physical properties of furfural solvent, which has different solubilities for various components contained in the oil (which is a component of wax oil), it has high solubility for polycyclic aromatic hydrocarbons with short side chains, as well as colloids, sulfur and nitrogen compounds, while it is insoluble or sparingly soluble for aromatic hydrocarbons with few rings and long side chains, as well as n-cycloalkanes and alkanes. The residual oil and extracted oil are obtained through liquid-liquid extraction technology.

[0003] The commonly used extraction method is as follows: the raw material is fed from the bottom of the extraction tower, and the solvent furfural is fed from the top of the extraction tower. A circulating heat exchanger is set up at the bottom of the extraction tower to help control the temperature at the bottom of the tower. During the extraction process, the raw material in the extraction tower gradually flows to the top of the extraction tower, and the furfural gradually flows to the bottom of the extraction tower, so that some substances in the raw material (polycyclic aromatic hydrocarbons and colloids, sulfur and nitrogen compounds) enter the furfural. The raffinate is obtained at the top of the extraction tower, and the extract is obtained at the bottom of the extraction tower. The raffinate and the extract are sent to the subsequent recovery unit to recover the solvent and obtain the raffinate oil and the extract oil.

[0004] When using the above-mentioned method for furfural extraction, the raw materials are generally vacuum distillate oils and light deasphalted oils, which are waxy oil components with relatively low viscosity (viscosity of about 4-40 cst at 100℃). The operating temperature of the extraction tower is relatively high, with the top temperature of the tower being 105℃-145℃; the temperature difference between the bottom and top of the extraction tower is large, generally 20-35℃. When the raw materials are furfural extract oils, high aromatic oils in the treated slurry, and other waxy oil components, due to the high viscosity (viscosity of about 20-200 cst at 100℃) and high aromatic content of these raw materials, the process requires a low extraction temperature (generally less than 80℃) and a small extraction temperature difference (the temperature difference between the top and bottom of the extraction tower is generally around 10℃). The distribution of solvent and raw materials in the tower is greatly affected by the properties of the materials in the tower (such as material viscosity, surface tension, density, etc.) and the design of the tower internals (tower packing, distributors, etc.). Under this extraction method, the solvent ratio required for extraction is large, and the energy consumption of the equipment is high.

[0005] In related technologies, such as patent publication number CN116769507A, a solvent deasphalting extraction tower and a method for solvent deasphalting are disclosed. The extraction tower includes an extraction section and a settling section. The extraction section is located below the settling section. A feed oil inlet is provided on the side wall of the tower body between the extraction section and the settling section. A solvent inlet for the extraction section is located below the extraction section. At least two high-temperature solvent inlets for the settling section are uniformly arranged axially on the side wall of the settling section. The solvent deasphalting method includes the following steps: (1) The raw oil and diluent are mixed and added to the extraction tower, and then contacted countercurrently with the solvent added to the bottom of the extraction tower to achieve the initial separation of light and heavy components; (2) The light component obtained in step (1) enters the settling section of the extraction tower and is heated by the high-temperature solvent added to the settling section. The temperature of the settling section increases from bottom to top, and the deasphalted oil is extracted from the top of the extraction tower; (3) The heavy component obtained in step (1) enters the heavy phase settling zone at the bottom, and the deasphalted bitumen is extracted from the bottom of the extraction tower; wherein, the operations of steps (2) and (3) are not sequential.

[0006] Patent publication numbers CN105400545A and CN105400545B propose a method and system for separating heavy oil. The method uses an extraction tower with multiple packing sections in the upper region and a distributor between adjacent packing sections. Supercritical solvent from a supercritical solvent recovery tower is introduced through the distributor, so that the heavy components in the deasphalted oil phase in the upper part of the extraction tower can be further separated.

[0007] The published patents CN116769507A, CN105400545A, CN105400545B and this patent differ in terms of extraction principle, extraction method, raw materials, products, extraction solvent, and extraction pressure. The published patents are not suitable for processing wax oil components and cannot selectively extract aromatic and non-aromatic substances in wax oil.

[0008] Patent publication number CN208799802U proposes a secondary extraction tower. The main improvement of this method is the introduction of a static mixer at the feed inlet of the extraction tower to improve the mixing effect. However, this extraction tower structure cannot solve the problem of material backmixing inside the extraction tower. The solvent and feed, temperature gradient control at the top and bottom of the extraction tower, and the design of the extraction packing are all conventional practices, exhibiting inherent defects of conventional technologies. Summary of the Invention

[0009] In order to reduce the amount of solvent used in extraction and thus reduce extraction energy consumption, this application provides an extraction apparatus and extraction method.

[0010] In a first aspect, this application provides an extraction apparatus, which adopts the following technical solution: An extraction apparatus includes an extraction tower; the extraction tower is provided with multiple sections of extraction packing to form multiple extraction zones within the extraction tower, and the multiple sections of extraction packing divide the extraction tower into multiple containment zones; the extraction tower is provided with multiple solvent inlets, which are located in different containment zones; the extraction tower is provided with a raw material inlet, which is located in a containment zone near the bottom of the extraction tower; the top of the extraction tower is provided with a raffinate outlet, and the bottom of the extraction tower is provided with an extractable liquid outlet.

[0011] By adopting the above technical solution, the solvent can be injected through multiple solvent inlets, thereby controlling the good distribution of the solvent in the tower, reducing the amount of solvent used and the extraction energy consumption. In addition, the injection of solvent through multiple solvent inlets can reduce backmixing of materials in the tower, better regulate the temperature distribution of the extraction tower, thereby improving the extraction effect of raw materials and increasing the yield of the target product.

[0012] Preferably, the extraction tower is equipped with multiple temperature detection points, which are located in different extraction zones.

[0013] By adopting the above technical solution, the setting of multiple temperature detection points combined with the injection of multiple solvents can improve the accuracy of temperature control in the extraction tower, thereby making the temperature distribution at the top and bottom of the extraction tower more reasonable. The raw materials processed by the published patents CN116769507A, CN105400545A, and CN105400545B are suitable for processing heavy oils such as residue oil; the solvents used are light hydrocarbons (propane, butane, C3-C5 alkanes and cycloalkanes); the extraction solvent has a lower density than the raw material, so it is added from the bottom of the extraction section, while the raw material is fed from the top of the extraction section, and the density difference is used to... Countercurrent extraction is achieved within the tower. To ensure uniform temperature in the settling section, multiple solvent inlets at the top are located in the settling section. The extraction principle utilizes the good solubility of the solvent for saturated hydrocarbons and aromatics in heavy oils such as residual oil to extract the oils from the feedstock. The resulting products are deasphalted oil (or light deasphalted, heavy deasphalted) and deoiled asphalt. This patent uses a light hydrocarbon solvent, and in order to maintain the liquid-phase operation required for extraction, the extraction operation pressure is relatively high (3-10 MPa or 2-6 MPa). This patent is not suitable for processing wax oil components, and the solvent used does not have selective solubility for aromatics and saturated hydrocarbons in the feedstock.

[0014] This patent applies to the processing of wax oil components, using furfural or other polar solvents. The principle is based on the solvent's good solubility for polycyclic short-chain aromatics, gums, sulfur, and nitrogen compounds (referred to as aromatics), while being insoluble or sparingly soluble for oligocyclic long-chain aromatics, n-cycloalkanes, and alkanes (referred to as non-aromatics). This separates the aromatics from the non-aromatics in the raw material. The solvent used in this patent has a higher density than the raw material. The solvent is fed from the top of the extraction tower, while the raw material is fed from the bottom, achieving countercurrent extraction within the tower through the density difference. Multiple solvent feeds are provided into the extraction section, with controllable temperature and flow rates for each. Different specific surface areas are used in the extraction packing to improve mass transfer efficiency. The solvent used in this patent has a low vapor pressure, requiring only a slightly positive or low pressure for the extraction operation.

[0015] Preferably, the extraction packing is in the form of random packing and redistribution packing, or a combination of random and structured packing and redistribution packing.

[0016] By adopting the above technical solutions, the extraction packing in this application is in the form of random packing and redistributed packing or a combination of random and structured packing and redistributed packing, which has the advantages of low cost, large throughput, reusability, and easy cleaning and maintenance.

[0017] Preferably, the random packing includes any one or a combination of at least two of the following: flat rings, Raschig rings, Pall rings, conjugate rings, rectangular saddle rings, or stepped rings; redistribution packing is provided between or within each section of the packing; the structured packing is corrugated packing or grid packing.

[0018] Preferably, both the solvent inlet and the raw material inlet are connected to a distributor.

[0019] By adopting the above technical solution, the distributor configuration improves the uniformity of the dispersion of raw materials and solvents inside the tower.

[0020] Preferably, the distributor is a tubular distributor.

[0021] By adopting the above technical solution, the tubular distributor used in this application has the advantages of easy uniform material distribution, low cost, simple operation and convenient maintenance. In addition, the use of a tubular distributor makes it easy for workers to directly remove the part of the tubular distributor located in the extraction tower and then replace the extraction packing, thereby achieving the purpose of improving the replacement efficiency of the extraction packing.

[0022] Preferably, the top and bottom of the extraction tower are provided with coalescing packing.

[0023] By adopting the above technical solution, the setting of coalescing packing can coalesce solvent-containing materials at the top and bottom of the extraction column, thereby reducing solvent carryover in the materials and improving the sedimentation effect.

[0024] Preferably, the specific surface area of ​​the multiple sections of the extraction packing decreases sequentially along the direction from the top of the extraction column to the bottom.

[0025] By adopting the above technical solution, the viscosity of the material in the extraction tower gradually increases along the direction from the top of the tower to the bottom. When the specific surface area of ​​the extraction packing remains unchanged, the material flow velocity at the top of the extraction tower is high, while the material flow velocity in the middle and lower parts of the extraction tower is slow, thus affecting the mass transfer effect and throughput in the extraction tower.

[0026] Secondly, this application provides an extraction method, which adopts the following technical solution: An extraction method includes the following steps: S1. Pre-dilution: Mix a portion of the solvent with the raw material to obtain a pre-diluted mixture, and then inject the pre-diluted mixture into the extraction tower; S2, Extraction: The remaining solvent is divided into multiple streams and injected into different extraction zones of the extraction tower, and the temperature and flow rate of each solvent stream are controlled. S3. Extraction liquid collection: After extraction, the raffinate obtained from the top of the extraction tower is sent downstream to recover the solvent. After extraction, the extract obtained from the bottom of the extraction tower is sent downstream to recover the solvent under interface control.

[0027] By adopting the above technical solution, after the materials in steps S1 and S2 enter the extraction tower, the solvent and raw material come into countercurrent contact in the extraction tower. The solvent dissolves the aromatic components (polycyclic short-chain aromatics and colloids, sulfur and nitrogen compounds, etc.) in the raw material to form a heavy phase that enters the bottom of the tower. The non-aromatic components (short-chain aromatics and n-cycloalkanes, alkanes, etc.) in the raw material that are not dissolved by the solvent or are only partially dissolved are the light phase that enters the top of the tower. The extraction method of this application has the advantages of high extraction efficiency, flexible and controllable operation, improved yield of the target product, reduced extraction solvent volume, and reduced energy consumption.

[0028] Preferably, the raw material is a wax oil component, which can be any one or a combination of at least two of the following: vacuum distillate oil, light deasphalted oil, furfural extracted oil, treated oil slurry high aromatic oil, waste lubricating oil, coal tar, and catalytic clarified oil; the solvent is a polar solvent, which can be furfural, N-methylpyrrolidone, phenol, or dimethyl sulfoxide.

[0029] By adopting the above technical solution, the extraction method of this application has a wide range of applications.

[0030] In summary, this application has the following beneficial effects: 1. This application utilizes multiple solvent inlets and tubular distributors for each feed to facilitate effective solvent distribution within the column, thereby reducing solvent consumption and energy consumption. Compared to conventional technologies, this reduces the solvent ratio by approximately 10-20% and increases the yield of the target product by approximately 1-5% while maintaining the same product specifications. Furthermore, the extraction device in this application reduces backmixing of materials within the column and improves the extraction efficiency. Additionally, this application controls the temperature gradient within the column by adjusting the injection temperature and flow rate of each solvent, further enhancing the extraction efficiency.

[0031] 2. This invention is suitable for processing a wide range of raw material viscosities, from low to high viscosity, and is particularly suitable for processing high viscosity oils. It is especially suitable for processes with low extraction temperatures and small temperature differences between the top and bottom of the extraction tower. The extraction device of this application can flexibly and accurately achieve temperature control of the extraction tower, making the temperature distribution at the top and bottom of the extraction tower more reasonable.

[0032] 3. The extraction packing material in the extraction tower of the present invention uses packing material with different specific surface areas from the top to the bottom of the tower, which adapts to the changes in the properties of the material inside the extraction tower from the top to the bottom of the tower, improves the mass transfer efficiency and throughput of the extraction packing material, and can improve the extraction effect, or improve the processing capacity of the extraction tower when the extraction effect is comparable.

[0033] 4. The extraction process in this invention eliminates the conventional bottom heat recovery design, which has the advantages of simple operation, easy maintenance, and cost savings.

[0034] 5. Compared with conventional technology, this method improves extraction efficiency and offers more flexible and controllable operation. Under the same product specifications, it can reduce the solvent ratio, lower equipment energy consumption, and increase the yield of the target product. The solvent ratio can be reduced by about 10-20%, and the yield of the target product can be increased by about 1-5%. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application.

[0036] Figure 2 This is a schematic diagram of the overall structure of the extraction tower in the embodiments of this application.

[0037] Figure 3 This is a schematic diagram of the overall structure of this application.

[0038] Reference numerals: 100, Extraction column; 110, First extraction zone; 120, Second extraction zone; 130, Third extraction zone; 140, Fourth extraction zone; 150, First containment zone; 160, Second containment zone; 170, Third containment zone; 180, Fourth containment zone; 190, Fifth containment zone; 200, Solvent inlet; 210, First main solvent inlet; 220, Second main solvent inlet; 230, Third main solvent inlet; 240, Distributor; 300, Raw material inlet; 400, Temperature detection point; 410, First temperature detection point; 420, Second temperature detection point; 430, Third temperature detection point; 440, Fourth temperature detection point; 450, Fifth temperature detection point; 500, Column body. Detailed Implementation

[0039] The following is in conjunction with the appendix Figure 1-2 The present application will be further described in detail with reference to the embodiments.

[0040] This application discloses an extraction apparatus.

[0041] Reference Figure 1The extraction apparatus includes an extraction tower 100, with coalescing packing material at both the top and bottom. This coalescing packing material can coalesce the solvent-containing material at the top and bottom of the extraction tower 100, reducing solvent carryover and improving sedimentation. In this application, the height of the coalescing packing material at the top and bottom is 1.2 to 1.8 meters. In this embodiment, the height of the coalescing packing material at both the top and bottom is 1.2 meters.

[0042] The extraction tower 100 is equipped with multi-stage extraction packing, typically consisting of 3 to 5 stages; in this embodiment, it has 4 stages. The multi-stage extraction packing is located between the coalescing packing at the bottom and top of the extraction tower 100, forming multiple extraction zones within the tower. Along the direction from the top to the bottom of the tower, these zones are sequentially designated as the first extraction zone 110, the second extraction zone 120, the third extraction zone 130, and the fourth extraction zone 140. The extraction packing can be of various types, including random packing, distributed packing, or a combination of random and structured packing and distributed packing. The total height of the extraction packing is 8 to 15 meters. Random packing includes any one or a combination of at least two of the following: flat rings, Raschig rings, Pall rings, conjugate rings, rectangular saddle rings, or stepped rings. Redistributed packing is provided between or within each packing stage. Structured packing uses corrugated or grid-type packing. In this embodiment, the extraction packing uses flat ring random packing, and the heights of each section of the extraction packing along the direction from the top of the extraction tower 100 to the bottom are 3 meters, 3 meters, 3 meters and 3 meters respectively. Distribution packing is provided between each section of the extraction packing. In this embodiment, the height of each section of distribution packing is 0.2 meters, and there are a total of 3 sections of distribution packing. The total height of the extraction packing (including random packing and distribution packing) is 12.6 meters.

[0043] Along the direction from the top to the bottom of extraction column 100, different packing ratios are used according to the different viscosities of the materials. The specific surface area of ​​the four extraction packing sections gradually decreases from the top to the bottom of the column. At the top, the material viscosity is low, so high specific surface area packing is used to improve mass transfer efficiency; at the bottom, the material viscosity is high, so low surface area packing is used to increase throughput, thereby improving the extraction mass transfer effect within extraction column 100. In this embodiment, from top to bottom, the extraction packing in the first extraction zone 110 has a specific surface area of ​​348 m². 2 / m 3 The specific surface area of ​​the extraction packing material corresponding to the first extraction zone 110 is 288 m². 2 / m 3 The extraction packing material corresponding to the third extraction zone 130 has a specific surface area of ​​228 m². 2 / m 3 The fourth stage extraction packing has a specific surface area of ​​189 m². 2 / m 3 .

[0044] Reference Figure 1 and Figure 2 The four-section extraction packing divides the extraction tower 100 into multiple containment zones. Along the direction close to the bottom of the extraction tower 100, the multiple containment zones are, in sequence, the first containment zone 150, the second containment zone 160, the third containment zone 170, the fourth containment zone 180, and the fifth containment zone 190.

[0045] The extraction tower 100 is provided with multiple solvent inlets 200. In this embodiment, three solvent inlets 200 are provided. In other embodiments, multiple solvent inlets 200 may be provided as needed. One of the three solvent inlets 200 is located in the first containment area 150 and is the first main solvent inlet 210; the second solvent inlet 200 is located in the second containment area 160 and is the second main solvent inlet 220; the third solvent inlet 200 is located in the third containment area 170 and is the third main solvent inlet 230.

[0046] The extraction tower 100 is provided with a raw material inlet 300, and the raw material inlet 300 is located in the fifth containment zone 190.

[0047] In order to improve the dispersion uniformity of solvent and raw material after entering the extraction tower 100, each solvent inlet 200 and raw material inlet 300 is connected to a distributor 240 in the extraction tower 100, and the distributor 240 is preferably a tubular distributor.

[0048] To facilitate temperature control within the extraction tower 100, multiple temperature detection points 400 are provided within the extraction tower 100. In this embodiment, five temperature detection points 400 are provided; in other embodiments, multiple temperature detection points 400 may be provided as needed. In this embodiment, along the direction from the top of the extraction tower 100 to the bottom, the five temperature detection points 400 are designated as a first temperature detection point 410, a second temperature detection point 420, a third temperature detection point 430, a fourth temperature detection point 440, and a fifth temperature detection point 450. The first temperature detection point 410 is located at the top of the extraction tower 100, while the second, third, and fourth temperature detection points 420, 430, and 440 are located in the first containment area 150, the second containment area 160, and the third containment area 170, respectively. The fifth temperature detection point 450 is located at the bottom of the extraction tower 100, on the side of the coalescing packing away from the top of the extraction tower 100. In other embodiments, temperature detection points 400 may be provided in other locations as needed.

[0049] The raw materials used in this application are wax oil components, which can be any one or a combination of at least two of the following: vacuum distillate oil, light deasphalted oil, furfural extracted oil, high aromatic oil for treating oil slurry, waste lubricating oil, coal tar, and catalytic clarified oil.

[0050] The solvent is a polar solvent, such as furfural, N-methylpyrrolidone, phenol, or dimethyl sulfoxide. The solvent density is greater than that of the raw material, and the solvent has good selectivity. It can selectively dissolve polycyclic short-chain aromatic hydrocarbons, colloids, sulfur and nitrogen compounds, as well as aromatic hydrocarbons with few ring long side chains, n-cycloalkanes, alkanes, etc.

[0051] Based on the aforementioned extraction apparatus, this application also proposes an extraction method. In this embodiment, the raw material processed is high-aromatic oil in a treated oil slurry, the solvent used is furfural, the target product is raffinate oil, the byproduct is extracted oil, and the total solvent ratio is 2.2, where the solvent ratio refers to the solvent volumetric flow rate divided by the raw material volumetric flow rate. In this application, the temperature gradient between the top and bottom of extraction tower 100 is 5–35°C; in this embodiment, the temperature gradient is 10°C. The operating temperature at the top of extraction tower 100 is 45–150°C; in this embodiment, the temperature at the top of extraction tower 100, i.e., the temperature at the first temperature detection point 410, is 60°C. In this application, the operating temperature at the bottom of extraction tower 100 is 40–120°C; in this embodiment, the temperature at the bottom of extraction tower 100, i.e., the temperature at the fifth temperature detection point 450, is 50°C. In this application, the operating pressure of the extraction tower is 0.01–1.5 MPa; in this embodiment, the operating pressure is 0.5 MPa. Other operating parameters can be flexibly adjusted.

[0052] One specific extraction method includes the following steps: S1. Pre-dilution: A portion of the solvent is used as a pre-dilution solvent and mixed thoroughly with the raw material in a raw material pre-dilution mixer to obtain a pre-dilution mixture. The pre-dilution mixture is then injected into the extraction tower. The pre-dilution solvent ratio is 0.2 to 1, and the temperature of the pre-dilution mixture entering the extraction tower 100 is 40°C to 130°C. In this embodiment, the pre-dilution solvent ratio is 0.5, and the temperature of the pre-dilution mixture is 50°C. S2. Extraction: The remaining solvent is divided into three main solvent streams and injected into the corresponding containment areas of different extraction towers 100 through the first main solvent inlet 210, the second main solvent inlet 220, and the third main solvent inlet 230, respectively, via the corresponding distributors 240. The total volume of the three main solvent streams and the volume ratio of the raw material are 0.2 to 3. In this embodiment, the main solvent in the first main solvent inlet 210 has its temperature TS1 controlled at 60°C by the temperature control valve V8, and the solvent ratio is controlled at 1 by the flow control valve F1. The main solvent in the second main solvent inlet 220 has its temperature TS2 controlled at 57°C by the temperature control valve V9, and the solvent ratio is controlled at 0.4 by the flow control valve F2. The third temperature detection point 430 in the extraction tower 100 is also controlled at 57°C. The main solvent in the third main solvent inlet 230 has its temperature TS3 controlled at 54°C by the solvent cooler E1, and the solvent ratio is controlled at 0.3 by the flow control valve F3. The extraction tower 100... The fourth temperature detection point 440 is controlled at 54℃; the raw material is fully mixed with the pre-diluted solvent in the raw material pre-diluted mixer M by controlling a certain flow rate through the regulating valve V4, and the raw material temperature TS4 is controlled at 50℃ through the raw material cooler E2. It then enters the extraction tower 100 from the raw material inlet 300 and the distributor 240 at the raw material inlet 300, and the fifth temperature detection point in the extraction tower 100 is controlled at 50℃. In this application, the total ratio of the main solvent is 1.7. In other embodiments, the temperature of the main solvent entering the extraction tower can be controlled according to the temperature gradient required by the extraction tower, and the temperatures of each solvent can be the same or different. The temperature of the main solvent is 45℃~150℃.

[0053] S3. Extraction liquid collection: After extraction, the raffinate (raffinate oil and a small amount of solvent mixture) obtained from the top of the extraction tower 100 is coalesced and settled in the top coalescer and then sent downstream to recover the solvent. After extraction, the extract (extracted oil and a large amount of solvent mixture) obtained from the bottom of the extraction tower 100 is coalesced and settled in the bottom coalescer and then sent downstream to recover the solvent under the control of the interface.

[0054] In this application, the temperature of the extraction tower is regulated by controlling the temperatures of the three main solvent streams and the feed stream, ensuring a good temperature distribution between the top and bottom of the extraction tower 100. This eliminates the need for a bottom circulation system at the bottom of the extraction tower 100, simplifying its structure and reducing its cost. Furthermore, controlling the injection temperature and flow rate of each solvent stream further improves the extraction efficiency. Additionally, the solvents at the second main solvent inlet 220 and the third main solvent inlet 230 are always fresh, which further enhances the extraction effect. The properties of the feedstock (high aromatic oil in the treated oil slurry) processed in this embodiment are recorded in Table 1, and the yield and properties of the main product, raffinate oil, produced in this embodiment are recorded in Table 2.

[0055] Table 1. Summary of properties of raw materials (processed oil slurry high aromatic oil) Density 20°C <![CDATA[kg / m 3 ]]> 1030 Four-component analysis - - Saturated portion wt% 24.0 Aromatic components wt% 68.3 gelatinous wt% 7.2 Asphalt wt% 0.5 Comparative Example This comparative example provides an extraction apparatus, referring to... Figure 3 The extraction apparatus includes a column body 500, with a raffinate outlet at the top and an extractant outlet at the bottom. Two sets of coalescing packing are installed inside the column body 500; one set is located at the top of the column body 500 and spaced apart from the top wall, and the other set is located at the bottom of the column body 500 and spaced apart from the bottom wall. Four sections of extraction packing are installed inside the column body 500, each 3.3 meters high, and these four sections are located between the two sets of coalescing packing, with gaps between adjacent sections.

[0056] In this comparative example, the extraction packing material was a random packing material, and the specific surface area of ​​all packing materials was 228 m². 2 / m 3 .

[0057] The column body 500 is provided with a feed inlet, which is located at the bottom of the column body 500 on the side of the coalescing packing close to the extraction packing. The column body 500 is also provided with a solvent inlet, which is located at the top of the column body 500 on the side of the coalescing packing close to the extraction packing.

[0058] Multiple temperature measuring points T01 to T05 are set on the tower body 500.

[0059] This comparative example also provides an extraction method, with the top temperature of column 500 at 62°C, the bottom temperature of column 500 at 50°C, the pre-diluted solvent ratio at 0.5, the main solvent ratio at 2, and the top of column 500 containing the target product, raffinate oil.

[0060] Due to limitations in temperature control methods within the extraction column of this comparative example, the temperature at the top of the column, T01, can only be controlled by the temperature of the solvent entering the column, and the temperature at the bottom of the column, T05, can only be controlled by the temperature of the feed entering the column. The intermediate temperature points, T02 to T04, cannot be well controlled, resulting in an uneven temperature distribution within the column. To make the temperature gradient as uniform as possible, the temperature at the top of the column was controlled at 62℃, resulting in a temperature difference of 12℃ between the top and bottom of the column, deviating from the desired 10℃ temperature difference range.

[0061] In order to obtain the same quality of residual oil as the example product, the required solvent ratio in this comparative example is 0.3 higher than that in the example.

[0062] This comparative example column has only one solvent feed at the top, resulting in severe backmixing of materials, low extraction efficiency, and a raffinate yield that is about 3% lower than that of the example. The raffinate yield and properties in this comparative example are recorded in Table 2.

[0063] Table 2. Comparison of main products (residual oil properties and yields) of the examples and comparative examples. Density 20°C <![CDATA[935.0kg / m 3 ]]> <![CDATA[934.8kg / m 3 ]]> Four-component analysis - - Saturated portion 74.0wt% 74.2wt% Aromatic components 23.5wt% 23.4wt% gelatinous 2.3wt% 2.2wt% Asphalt 0.2wt% 0.2wt% Rare oil yield 28.3wt% 25.2wt% This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. An extraction apparatus, characterized in that, The extraction tower (100) includes an extraction tower (100); the extraction tower (100) is provided with multiple extraction packing sections to form multiple extraction zones within the extraction tower (100), and the multiple extraction packing sections divide the extraction tower into multiple containment zones. The extraction tower (100) is provided with multiple solvent inlets (200), which are located in different containment zones. The extraction tower (100) is provided with a raw material inlet (300), which is located in a containment zone near the bottom of the extraction tower (100). The top of the extraction tower (100) is provided with a raffinate outlet, and the bottom of the extraction tower (100) is provided with an extract outlet. The extraction tower (100) is equipped with multiple temperature detection points (400), which are located in different containment areas. The extraction packing is in the form of random packing and redistributed packing or a combination of random and structured packing and redistributed packing. The extraction tower (100) is equipped with coalescing packing at both the top and bottom; Along the direction from the top of the extraction tower (100) to the bottom, the specific surface area of ​​the multiple sections of the extraction packing decreases sequentially; The raw materials are selected from any one or a combination of at least two of the following: vacuum distillate oil, light deasphalted oil, furfural extracted oil, high aromatic oil for treated slurry, waste lubricating oil, coal tar, and catalytic clarified oil; the solvent is selected from furfural, N-methylpyrrolidone, phenol, or dimethyl sulfoxide. The extraction packing material is set in 3-5 sections.

2. The extraction apparatus according to claim 1, characterized in that, The random packing includes any one or a combination of at least two of the following: flat rings, Raschig rings, Pall rings, conjugate rings, rectangular saddle rings, or stepped rings; redistribution packing is provided between or within each packing section; the structured packing uses corrugated packing or grid packing.

3. The extraction apparatus according to claim 1, characterized in that, Both the solvent inlet (200) and the raw material inlet (300) are connected to a distributor (240).

4. The extraction apparatus according to claim 3, characterized in that, The distributor (240) is a tubular distributor.

5. An extraction method using the extraction apparatus according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Pre-dilution and raw material addition: Mix part of the solvent with the raw material to obtain a pre-diluted mixture, and inject the pre-diluted mixture into the extraction tower (100). S2, Extraction: The remaining solvent is divided into multiple streams and injected into different extraction zones of the extraction tower (100), and the temperature and flow rate of each solvent stream are controlled. S3, Extraction liquid collection: After extraction, the raffinate obtained from the top of the extraction tower (100) is sent downstream to recover the solvent, and the extract obtained from the bottom of the extraction tower (100) is sent downstream to recover the solvent under the control of the interface. The raw materials are selected from any one or a combination of at least two of the following: vacuum distillate oil, light deasphalted oil, furfural extracted oil, treated oil slurry high aromatic oil, waste lubricating oil, coal tar, and catalytic clarified oil; the solvent is selected from furfural, N-methylpyrrolidone, phenol, or dimethyl sulfoxide.

Images