A system for integrated extraction and separation of aromatics from reformed gasoline

Abstract

The application relates to the field of petroleum chemical industry, in particular to a system for integrated extraction and separation of aromatic hydrocarbons in reforming gasoline; the system comprises an extraction unit, an integrated unit and an extraction column and an extraction reboiler, both ends of the extraction reboiler are communicated with the extraction column; the integrated unit comprises an integrated column and an integrated reboiler, the integrated column comprises a partition plate and a plurality of trays, the trays are horizontally spaced in the integrated column, so that the integrated column is divided into a common rectification section, a middle treatment section and a common stripping section from top to bottom; the partition plate is arranged in the middle treatment section and is perpendicular to the plane of the tray; the integrated reboiler is communicated with the bottom discharge port of the integrated column, both ends of the integrated reboiler are communicated with the discharge port of the integrated column; the extraction column and the integrated column are communicated; by adopting the mode of the extraction column matched with the extraction reboiler, and then through the feed pre-fractionation section, the common rectification section, the common stripping section and the side product extraction section in the integrated column, the short-process extraction and separation of the aromatic hydrocarbons in the reforming gasoline is realized.

Description

Technical Field

[0001] This application relates to the petrochemical field, and in particular to a system for integrated extraction and separation of aromatics from reformed gasoline. Background Technology

[0002] Aromatics are essential raw materials for petrochemicals, with benzene, toluene, and xylene being the most important. With the development of the oil refining industry, the demand for aromatics, one of the raw materials required for refining, has been increasing. Therefore, petroleum aromatics have become a major source of aromatics. However, with increasingly stringent environmental regulations, the specifications for petroleum products (such as fuels) are also becoming more stringent, generally requiring an aromatic content of ≤35%, of which the benzene content must be <0.8%. Since aromatics are crucial raw materials for producing petroleum products from refining, it is necessary to separate aromatics from the reformed gasoline components produced in the oil refining process.

[0003] Currently, the separation methods for reformed gasoline components mainly target the C6-C7 components of reformed gasoline. Sulfolane is used as a solvent to extract and separate the aromatics benzene and toluene, and then distillation is used to extract and separate xylene. Generally, the extraction and separation system includes extraction, aromatic recovery, benzene tower and toluene tower. Not only is the process long and energy-intensive, but the multi-stage process also results in a large footprint, leading to high investment and operating costs.

[0004] Therefore, how to provide a short-process extraction and separation system for aromatics to shorten the extraction and separation process of aromatics in reformed gasoline is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] This application provides a system for integrated extraction and separation of aromatics from reformed gasoline, in order to solve the problem of excessively long processes in the prior art for extracting and separating aromatics from reformed gasoline.

[0006] This application provides a system for integrated extraction and separation of aromatics from reformed gasoline, the system comprising:

[0007] An extraction unit, comprising an extraction tower and an extraction reboiler, wherein both ends of the extraction reboiler are connected to the extraction tower to achieve the recycling of a solvent rich in aromatics.

[0008] An integrated unit includes an integrated column and an integrated reboiler. The integrated column includes a partition and multiple trays, which are laterally spaced within the integrated column to divide it into a common rectification section, a middle processing section, and a common stripping section from top to bottom. The partition is located within the integrated column and is perpendicular to the plane of the trays within the middle processing section to divide it into a feed pre-fractionation section and a side-stream product collection section.

[0009] The integrated reboiler is connected to the bottom outlet of the integrated column, and both ends of the integrated reboiler are connected to the outlet of the integrated column, so as to realize the heating treatment of the lean solvent after distillation.

[0010] The bottom of the extraction tower is connected to the middle of the integrated tower, and the middle of the extraction tower (11) is connected to the bottom of the integrated tower (21) to achieve the recycling of lean solvent.

[0011] Optionally, the extraction unit further includes an extraction condenser, which is connected to the top of the extraction tower. The extraction condenser includes a first outlet and a second outlet. The inlet and the first outlet of the extraction condenser are connected to the top of the extraction tower. The second outlet of the extraction condenser is used to discharge raffinate product that does not contain aromatics.

[0012] Optionally, the integrated unit further includes an integrated condenser, both ends of which are connected to the top of the integrated tower to achieve the distillation of aromatics.

[0013] Optionally, the operating pressure of the extraction tower is ≤0.1MPa, the operating temperature at the top of the extraction tower is 90℃~110℃, and the operating temperature at the bottom of the extraction tower is 165℃~178℃.

[0014] Optionally, the operating pressure of the common distillation section is 20 kPa to 60 kPa.

[0015] Optionally, the operating temperature of the common distillation section is 45℃~60℃.

[0016] Optionally, the temperature of the side-line product outlet section is 75℃~90℃.

[0017] Optionally, the operating temperature of the common stripping section is 165℃~178℃.

[0018] Optionally, the mass ratio of lean solvent to reformed gasoline in the extraction tower is 2 to 6.

[0019] Optionally, the extraction tower has 40 to 60 theoretical trays; the integrated tower has 45 to 75 theoretical trays.

[0020] The technical solutions provided in this application have the following advantages compared with the prior art:

[0021] This application provides an integrated extraction and separation system for aromatics from reformed gasoline. By first employing an extraction tower paired with an extraction reboiler, countercurrent contact between the lean solvent and the reformed gasoline is achieved. This ensures sufficient extraction of aromatics from the C6-C7 components of the reformed gasoline by the lean solvent. Then, in the pre-fractionation section of the integrated tower, benzene and some toluene from the aromatics enter the rectification section, while the remaining toluene and rich solvent enter the common stripping section, thus achieving initial separation of the lean solvent and aromatics. Through the rectification section, benzene and some toluene are separated and collected. Further stripping allows for a more refined separation of aromatics and lean solvent, promoting the separation of the remaining toluene from the lean solvent, thereby separating the lean solvent. Finally, by limiting the connection between the bottom of the extraction tower and the integrated tower, the separated lean solvent can be recycled. Thus, the separation and collection of aromatics from reformed gasoline can be achieved through only two main processing towers, shortening the extraction and separation process for aromatics from reformed gasoline and realizing a short-process extraction and separation of aromatics from reformed gasoline. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the system structure provided in the embodiments of this application;

[0025] Figure 2 A schematic diagram of the process system provided as a comparative example in this application;

[0026] Among them, 1-extraction unit, 11-extraction tower, 12-extraction reboiler, 13-extraction condenser, 2-integrated unit, 21-integrated tower, 22-integrated reboiler, 23-baffle, 24-tray, 25-integrated condenser, 3-recovery tower, 4-benzene tower, 5-toluene tower, A-reformed gasoline, B-raffinate oil, C-rich solvent, D-benzene, E-toluene, F-xylene, G-lean solvent, Ⅰ-feed pre-fractionation section, Ⅱ-common rectification section, Ⅲ-side-stream product collection section, Ⅳ-common stripping section. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0029] like Figure 1 As shown in the embodiment of this application, a system for integrated extraction and separation of aromatics from reformed gasoline is provided, the system comprising:

[0030] Extraction unit 1, which includes an extraction tower 11 and an extraction reboiler 12, with both ends of the extraction reboiler 12 connected to the extraction tower 11 to achieve the recycling of the solvent rich in aromatics.

[0031] The integrated unit 2 includes an integrated tower 21 and an integrated reboiler 22. The integrated tower 21 includes a partition 23 and multiple trays 24. The trays 24 are arranged laterally at intervals within the integrated tower 21, so that the integrated tower 21 is divided from top to bottom into a common rectification section II, a middle processing section, and a common stripping section IV. The partition 23 is disposed within the integrated tower 21 and is perpendicular to the plane of the trays 24 within the middle processing section, so that the middle processing section is divided into a feed pre-fractionation section I and a side-stream product collection section III.

[0032] The integrated reboiler (22) is connected to the bottom outlet of the integrated tower (21), and both ends of the integrated reboiler (22) are connected to the outlet of the integrated tower (21) to achieve heating treatment of the lean solvent after distillation;

[0033] The bottom of the extraction tower (11) is connected to the middle of the integrated tower (21), and the middle of the extraction tower (11) is connected to the bottom of the integrated tower (21) to realize the recycling of lean solvent.

[0034] In this embodiment of the application, the system includes an extraction unit 1 and an integration unit 2. The extraction unit 1 is used to achieve countercurrent contact between lean solvent and reformed gasoline and extract aromatics. The integration unit 2 is then used to process the rich solvent from which the aromatics have been extracted, thereby achieving the separation of benzene, toluene and lean solvent in the aromatics.

[0035] Extraction column 11 is a device that involves counter-current contact between a lean solvent and the C6-C7 components of reformed gasoline within the column. Aromatics such as benzene, toluene, and xylene (in trace amounts) are extracted from the gasoline components into the lean solvent. At the top of extraction column 11, aromatic-free alkanes are obtained. These aromatic-free alkanes are referred to in the industry as raffinate, which can be directly discharged from the system for the next process. At the bottom of extraction column 11, an aromatic-rich solvent is obtained. Extraction column 11 can employ liquid-liquid extraction or extractive distillation techniques. Cooling facilities are installed at the top of extraction column 11, and a reboiler is installed at the bottom. The trays can be either sieve trays or valve trays.

[0036] Integrated column 21 is a wall-splitting column that integrates the separation of aromatics from the solvent in a solvent-rich environment, as well as the separation of aromatics into products such as benzene and toluene, into a single column. A wall-splitting column is a distillation device with a partition 23 located in the middle of a conventional distillation column. The partition 23 is installed vertically to prevent lateral mixing of the liquid and gas phases on both sides. The internal structure of the wall-splitting column is divided into a common rectification section II, a feed pre-fractionation section I, a side-stream product collection section III, and a common stripping section IV. The feed pre-fractionation section I and the side-stream product collection section III are separated by a partition 23. In feed pre-fractionation section I, the feed undergoes rough fractionation, allowing a mixture of benzene, toluene, and xylene to enter the common rectification section II for distillation, producing benzene gas. Toluene is further separated into toluene product in the side-stream product collection section III. At this point, the lean solvent and the remaining toluene are separated in the common stripping section IV. The lean solvent is collected at the bottom of the integrated column 21, while the remaining toluene flows out in the side-stream collection section III, thus completing the separation of aromatics and lean solvent within the integrated column. The side-stream product collection section III, together with the common rectification section II and the common stripping section IV, constitutes the main column, where light, medium, and heavy components are separated. A condenser is installed at the top of the column, and a reboiler is installed at the bottom. The rich solvent enters the pre-fractionation section I of the integrated column 21. Benzene is obtained at the top of the column, toluene is obtained from the side-stream product collection section III, and xylene is obtained from the bottom of the side-stream product collection section III (intermittent, normally no collection is required). The lean solvent is recycled back to the extraction column 11 at the bottom. The integrated column 21 is a vacuum column operating under negative pressure.

[0037] To ensure that the lean solvent used does not decompose, the bottom of the extraction tower 11 and the integrated tower 21 in this application are heated by steam, heat transfer oil or other media, and the temperature of the heating medium is controlled at 200℃~220℃ to ensure that the operating temperature in the extraction tower 11 and the integrated tower 21 is within the expected range.

[0038] Lean solvents refer to solvents that can extract aromatics from reformed gasoline but have not yet extracted the aromatics, including sulfolane organic solvents.

[0039] Rich solvent refers to a poor solvent from which aromatics have been extracted.

[0040] The trays 24 of the integrated tower 21 are generally set to have 45 to 75 pieces, and preferably 51 to 69 pieces. Correspondingly, the trays 24 of the extraction tower 11 are generally set to have 40 to 60 pieces, and preferably 45 to 50 pieces.

[0041] In some optional embodiments, the extraction unit 1 further includes an extraction condenser 13, which is connected to the top of the extraction tower 11. The extraction condenser 13 includes a first outlet and a second outlet. The inlet and the first outlet of the extraction condenser 13 are connected to the top of the extraction tower 11. The second outlet of the extraction condenser 13 is used to discharge raffinate product that does not contain aromatics.

[0042] In this embodiment of the application, the extraction unit 1 further includes an extraction condenser 13, which is used to condense the non-C6 to C7 components in the reformed gasoline after countercurrent contact to form raffinate components, which are then collected and sent to the next stage.

[0043] In some alternative embodiments, the integrated unit 2 further includes an integrated condenser 25, both ends of which are connected to the top of the integrated tower 21 to achieve the distillation of aromatics.

[0044] In this embodiment, the integrated unit 2 further includes an integrated condenser 25, which is used to further separate the benzene and toluene separated from the aromatics in the distillation stage, so that the benzene is condensed into liquid and discharged from the integrated tower 21, thus completing the collection of benzene.

[0045] In some optional embodiments, the operating pressure of the extraction tower 11 is ≤0.1MPa, the operating temperature at the top of the extraction tower 11 is 90℃~110℃, and the operating temperature at the bottom of the extraction tower 11 is 165℃~178℃.

[0046] In this embodiment, the positive effect of limiting the operating pressure of the extraction tower 11 is that, based on the extraction temperature of the reformed gasoline and lean solvent in the extraction tower 11, combined with the characteristics of the reformed gasoline and lean solvent, the countercurrent contact effect of the reformed gasoline and lean solvent can be guaranteed.

[0047] Limiting the operating temperatures at the top and bottom of extraction tower 11 ensures effective countercurrent contact between reformed gasoline and lean solvent, facilitating the entry of aromatics into the lean solvent to form a rich solvent, which in turn facilitates the subsequent processing by integrated tower 21.

[0048] In some alternative embodiments, the operating pressure of the common rectification section II is 20 kPa to 60 kPa.

[0049] In this embodiment of the application, the positive effect of limiting the operating pressure of the common distillation section II to 20 kPa to 60 kPa is that within this operating pressure range, the distillation can be carried out under negative pressure, thereby ensuring that benzene and a portion of toluene are distilled out at an appropriate temperature, while toluene is discharged from the system through the side-stream product collection section III, thereby achieving the separation of benzene and a portion of toluene.

[0050] In some optional embodiments, the operating temperature of the common distillation section II is 45°C to 60°C.

[0051] In this embodiment of the application, the positive effect of limiting the operating temperature of the common distillation section II to 45°C to 60°C is that within this temperature range, the distillation of benzene and a portion of toluene can be carried out smoothly, thereby obtaining benzene products with the expected temperature and expected purity from the top of the integrated column 21.

[0052] In some alternative embodiments, the temperature of the side-line product exit section III is 75°C to 90°C.

[0053] In this embodiment of the application, the positive effect of limiting the temperature of the side-stream product outlet section III to 75°C to 90°C is that within this temperature range, it can ensure that the toluene produced in the stripping stage and the toluene remaining in the rectification stage are discharged from the system through the side-stream product outlet section III. At the same time, it can also ensure that some xylene impurities mixed in some reformed gasoline are separated from toluene and discharged through the lower section of the side-stream product outlet section III.

[0054] In some optional embodiments, the operating temperature of the common stripping section IV is 165°C to 178°C.

[0055] In this embodiment of the application, limiting the operating temperature of the common stripping section IV to 165°C to 178°C has the positive effect that within this temperature range, the lean solvent separated from the common stripping section IV can be kept stable in a liquid state, avoiding thermal decomposition of the lean solvent and affecting its recycling.

[0056] In some alternative embodiments, the mass ratio of lean solvent to reformed gasoline in the extraction tower 11 is 2 to 6.

[0057] In the embodiments of this application, the positive effect of limiting the mass ratio of lean solvent to reformed gasoline to 2 to 6 is that within this mass ratio range, it can be ensured that the lean solvent extracts the aromatics from the reformed gasoline, thereby ensuring the collection of benzene and toluene from the aromatics in the subsequent distillation stage.

[0058] The mass ratio of lean solvent to reformed gasoline can be 3 to 4.

[0059] In some optional embodiments, the extraction tower 11 has a theoretical number of 40 to 60 trays; the integrated tower 21 has a theoretical number of 45 to 75 trays.

[0060] In this embodiment, the theoretical number of trays in the extraction tower 11 and the integrated tower 21 is limited. The theoretical number of trays ensures the countercurrent contact time between the lean solvent and reformed gasoline in the extraction tower 11, ensuring that aromatics in the reformed gasoline enter the lean solvent to form a rich solvent, thereby improving the processing efficiency of aromatics. At the same time, it also ensures that the functions of each working area in the integrated tower 21 are normal, thereby improving the separation efficiency of benzene and toluene in aromatics.

[0061] Due to limitations such as the actual environment of the equipment and the specifications of different reformed gasoline, the actual number of trays is generally higher than the theoretical number of trays.

[0062] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0063] Example 1

[0064] like Figure 1 As shown in the embodiments of this application, an integrated extraction and separation system for aromatics from reformed gasoline is also provided, comprising:

[0065] Extraction unit 1 includes an extraction tower 11 and an extraction reboiler 12. Both ends of the extraction reboiler 12 are connected to the extraction tower 11 to realize the recycling of the solvent rich in aromatics.

[0066] Integrated unit 2 includes an integrated tower 21 and an integrated reboiler 22. The integrated tower 21 includes a partition 23 and multiple trays 24. The trays 24 are arranged laterally at intervals within the integrated tower 21, so that the integrated tower 21 is divided from top to bottom into a common rectification section II, a middle processing section, and a common stripping section IV. The partition 23 is disposed within the integrated tower 21 and is perpendicular to the plane of the trays 24 within the middle processing section, so that the middle processing section is divided into a feed pre-fractionation section I and a side-stream product collection section III.

[0067] The integrated reboiler 22 is connected to the bottom outlet of the integrated tower 21, and both ends of the integrated reboiler 22 are connected to the outlet of the integrated tower 21, so as to realize the heating treatment of the lean solvent after distillation.

[0068] The bottom of the extraction tower 11 is connected to the middle of the integrated tower 21, and the middle of the extraction tower 11 is connected to the bottom of the integrated tower 21, so as to realize the recycling of the lean solvent.

[0069] The extraction unit 1 also includes an extraction condenser 13, which is connected to the top of the extraction tower 11. The extraction condenser 13 includes a first outlet and a second outlet. The inlet and the first outlet of the extraction condenser 13 are connected to the top of the extraction tower 11. The second outlet of the extraction condenser 13 is used to discharge raffinate products that do not contain aromatics.

[0070] The integrated unit 2 also includes an integrated condenser 25, both ends of which are connected to the top of the integrated tower 21 to achieve solvent-rich distillation.

[0071] Example 3

[0072] Comparing Example 3 and Example 2, the differences between Example 3 and Example 2 are as follows:

[0073] The feedstock is a typical C6-C7 component of reformed gasoline, as shown in Table 1. The feed rate is 600,000 tons / year, the feed pressure is 0.2 MPa (g), the feed temperature is 110℃, and the mass ratio of lean solvent to reformed gasoline is 4.

[0074] Extraction tower 11 operates at a pressure of 0.04 MPa (g) and requires 74 trays. Integrated tower 21 is a split-wall tower, operating at a pressure of 30 kPa (a) and requiring 105 trays. Xylene is intermittently extracted after accumulating a certain amount in the product extraction section. The system used employs the following... Figure 1 As shown in Table 2, the process parameters are as follows.

[0075] Comparative Example 1

[0076] Comparative Example 1 and Example 3 will be compared. The difference between Comparative Example 1 and Example 3 is as follows:

[0077] The separation process employs extraction tower 11, recovery tower 3, benzene tower 4, and toluene tower 5.

[0078] The process conditions are as follows: the raw material is a typical reformed gasoline C6-C7 component, the composition of which is shown in Table 1; the feed rate is 600,000 tons / year; the feed pressure is 0.2 MPa (g); the feed temperature is 110℃; and the mass ratio of lean solvent to reformed gasoline is 4.

[0079] Extraction tower 11 operates at a pressure of 0.04 MPa (g) and requires 74 trays; recovery tower 3 operates at a pressure of 30 kPa (a) and requires 30 trays; benzene tower 4 operates at a pressure of 0.07 MPa (g) and requires 60 trays; toluene tower 5 operates at a pressure of 0.37 MPa (g) and requires 60 trays. The system used in the process flow is as follows: Figure 2 As shown in Table 2, the process parameters are as follows.

[0080] Relevant experimental and effect data:

[0081] Separation requirements: Based on the actual separation effect of each example and comparative example, benzene needs to meet the requirements of national standard GB / T3405, with a purity of 99.9% (mass), and toluene needs to meet the requirements of national standard GB / T 3406, with a purity of 99.9% (mass).

[0082] Table 1. Typical C6-C7 composition of reformed gasoline (wt%)

[0083]

[0084]

[0085] Table 2 Process Parameter Table

[0086]

[0087] As shown in Table 2, the energy can be saved by 31.6% by adopting the process flow and process system of this application.

[0088] As can be seen from the data in Examples 1-3, by using the process flow and process system of this application, the separation and collection of aromatics in reformed gasoline can be achieved in just two process steps, thereby shortening the extraction and separation process of aromatics in reformed gasoline and realizing the short-process extraction and separation of aromatics in reformed gasoline.

[0089] To further illustrate the operating procedure of this invention, the following is combined with... Figure 1 Further detailed description, but not limited to the embodiments. For example... Figure 1 As shown, the C6-C7 component A of the reformed gasoline enters the middle section of extraction tower 11, while the circulating lean solvent (sulfolane) enters the upper middle section of extraction tower 11. The two components contact counter-currently in extraction tower 11. The lean solvent extracts the aromatics from the gasoline components and serves as the rich solvent C, which is drawn from the bottom of the tower and enters integrated tower 21. The top material of extraction tower 21 is condensed and cooled to obtain a raffinate product free of aromatics. The rich solvent C enters the lower middle section of the feed pre-fractionation section I of integrated tower 21 for coarse separation of aromatics and solvent. The separated aromatics flow upwards into the common rectification section II for separation of benzene and toluene. The benzene at the top of the tower is condensed and refluxed, and the benzene product is drawn from the trays at the top 4-5 layers to ensure that the benzene product is water-free. The solvent flows downwards in the pre-fractionation section I into the common stripping section IV for fine separation of solvent and aromatics. The bottom material, free of aromatics, is obtained and returned to extraction tower 11 for recycling. Toluene is obtained in the middle of the side-stream product extraction section III, and xylene is occasionally obtained in the lower part of the extraction section (xylene is extracted when it accumulates to a certain level; normally no xylene is extracted). The bottom of extraction tower 11 and the bottom of integrated tower 21 are both heated by steam. To prevent the decomposition of the solvent sulfolane, the steam temperature is controlled at 200-220℃.

[0090] One or more technical solutions in the embodiments of this application have at least the following technical effects or advantages:

[0091] (1) The integrated extraction and separation system for aromatic hydrocarbons of reformed gasoline provided in this application uses an integrated tower 21 that is only a wall separator, which replaces the recovery tower 3, benzene tower 4, toluene tower 5 and xylene tower in the traditional process, reducing the number of towers and their auxiliary facilities by 2. The process is shorter and occupies less space, with the land area reduced by about 70%.

[0092] (2) The integrated extraction and separation system for aromatic hydrocarbons of reformed gasoline provided in this application has a high separation efficiency because the integrated tower 21 adopts a split-wall tower structure, which avoids the back-mixing effect of intermediate components. Therefore, the separation of products such as benzene, toluene, and solvents can be completed in one tower. Compared with conventional processes, the public works consumption is reduced by more than 30%.

[0093] (3) The integrated extraction and separation system for aromatics from reformed gasoline provided in this application embodiment reduces the number of main equipment by more than 65% and saves more than 50% of the total equipment investment compared with the traditional process.

[0094] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0095] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the orientation shown in the accompanying drawings. Furthermore, in the description of this application, the terms "comprising," "including," etc., mean "including but not limited to."

[0096] In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any actual relationship or order between these entities or operations. In this document, "and / or" describes the association between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c," or "at least one of a, b, and c," can both represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0097] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A process for the integrated extraction separation of aromatics from reformed gasoline, characterized in that, The method is implemented in a system for integrated extraction and separation of aromatics from reformed gasoline, which is composed of an extraction unit (1) and an integrated unit (2), wherein: The extraction unit (1) comprises an extraction column (11) and an extraction reboiler (12), both ends of the extraction reboiler (12) are communicated with the extraction column (11) to realize the cyclic treatment of the rich solvent containing aromatics; The integrated unit (2) comprises an integrated column (21) and an integrated reboiler (22), the integrated column (21) comprises a partition plate (23) and a plurality of trays (24), the trays (24) are transversely spaced in the integrated column (21) to divide the integrated column (21) into a common rectification section, a middle treatment section and a common stripping section from top to bottom; the partition plate (23) is arranged in the middle treatment section and is perpendicular to the plane of the trays (24) to divide the middle treatment section into a feed pre-fractionation section and a side product recovery section; The integrated reboiler (22) is communicated with the bottom discharge port of the integrated column (21), and both ends of the integrated reboiler (22) are communicated with the discharge ports of the integrated column (21) to realize the heating treatment of the stripped lean solvent; The bottom discharge port of the extraction column (11) is communicated with the feed pre-fractionation section (I) of the integrated column (21) for feeding the rich solvent into the integrated column for separation; The bottom discharge port of the common stripping section (IV) of the integrated column (21) is communicated with the middle feed port of the extraction column (11) to realize the cyclic utilization of the lean solvent; The extraction unit (1) further comprises an extraction condenser (13) communicated with the top of the extraction column (11), the extraction condenser (13) comprises a first discharge port and a second discharge port, the feed port of the extraction condenser (13) and the first discharge port are communicated with the top of the extraction column (11), and the second discharge port of the extraction condenser (13) is used for discharging raffinate oil products without aromatics; the theoretical tray number of the extraction column (11) is 40-60; the theoretical tray number of the integrated column is 45-75; The system is configured to simultaneously complete the separation of aromatics and solvent, the recovery of benzene product, the recovery of toluene product and the regeneration of lean solvent in the integrated column (21). The method comprises that C6-C7 components of the reforming gasoline enter the middle part of the extraction tower, the circulating lean solvent sulfolane enters the upper middle part of the extraction tower, and the two are countercurrently contacted in the extraction tower, the lean solvent extracts the aromatics in the reforming gasoline components as the rich solvent which is extracted from the bottom of the extraction tower and enters the integrated tower, the overhead material of the extraction tower is condensed and cooled to obtain the raffinate oil product without aromatics, the rich solvent enters the middle lower part of the feed pre-fractionation section of the integrated tower, the crude separation of the aromatics and the solvent is carried out, the separated aromatics flow upwards into the common rectification section to separate benzene and toluene, the overhead benzene is condensed and totally refluxed, and the benzene product is extracted from the tray at 4-5 layers of the top of the tower; the solvent flows downwards in the pre-fractionation section I into the common stripping section to carry out the fine separation of the solvent and the aromatics, the lean solvent without aromatics is obtained at the bottom of the tower and is returned to the extraction tower for recycling, and the toluene product is obtained in the middle part of the side product extraction section; The operating pressure of the extraction tower (11) is ≤0.1 MPa, the operating temperature of the top of the extraction tower (11) is 90-110℃, and the operating temperature of the bottom of the extraction tower (11) is 165-178℃; The operating pressure of the common rectification section is 20-60 kPa, and the operating temperature is 45-60℃; The temperature of the side product extraction section is 75-90℃; The operating temperature of the common stripping section is 165-178℃; The mass ratio of the lean solvent in the extraction tower (11) to the reforming gasoline is 2-6; The bottoms of the extraction tower and the integrated tower are both steam heated, and the steam temperature is controlled at 200-220℃.

2. The method of claim 1, wherein, The integrated unit (2) further comprises an integrated condenser (25), both ends of the integrated condenser (25) are communicated with the top of the integrated tower (21) to realize the fine rectification of the aromatics.

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