CN108949218A - For separating the next door column rectification system and method for catalytic reforming de-pentane oil - Google Patents

Abstract

The present invention relates to a kind of for separating the next door column rectification system of catalytic reforming de-pentane oil comprising prefractionator and benzenol hydrorefining, prefractionator is interior to be arranged vertical partition plate；Catalytic reforming de-pentane oil enters the feed side of prefractionator, at top, extraction is rich in the fraction of non-aromatics and benzene, exit side extraction is rich in the fraction of toluene, and the fraction including dimethylbenzene and heavy constituent of bottom extraction enters benzenol hydrorefining, and the top of benzenol hydrorefining produces xylene product；Condenser of the reboiler of prefractionator as benzenol hydrorefining.The invention further relates to a kind of methods with next door column rectification system separation catalytic reforming de-pentane oil.

Description

Dividing wall column rectification system and method for separating catalytic reforming depentanized oil

technical field

The invention relates to a rectifying system of a dividing wall tower for separating and catalytically reforming depentanized oil, belonging to the technical field of chemical production. The invention also relates to a method for separating catalytically reformed depentanized oil by using a rectifying system of a dividing wall column.

Background technique

Catalytic reforming is one of the important processes in petroleum refining. Naphtha is transformed into reformed oil rich in aromatics through catalytic reforming reaction. On the one hand, the reformed oil can be used as a blending gasoline component, and on the other hand, important chemical raw materials such as benzene, toluene, and xylene can be obtained. The processing capacity of catalytic reforming accounts for about 10-20% of the primary processing capacity of crude oil. Catalytic reforming units are large in scale, long in process, and large in number of equipment, and their energy consumption greatly affects the production cost of reformed products. Therefore, energy-saving measures for catalytic reforming have been widely concerned and researched.

At present, according to different types of reformed products, the process of separation after reforming is different. The separation process for pure production of blended gasoline components is relatively simple. Usually, it is the reformed oil after the reaction. After the components with carbon five and below are removed through the depentanizer, the reformed depentanized oil is obtained, and then the reformed oil is separated. The top of the reformed oil separation tower separates non-aromatics and benzene (or some toluene), and the bottom of the reformed oil separation tower produces components such as toluene and xylene, which are the blended gasoline components. In the separation process for the production of aromatic products, the reformed oil separation tower needs to remove non-aromatics, benzene and all toluene from the top of the tower, and then go to extractive distillation to obtain benzene and toluene products, and the bottom material of the reformed oil separation tower goes to the xylene tower, The xylene product is discharged from the top of the xylene tower, and the heavy component is discharged from the bottom of the tower as a blended gasoline component.

Toluene can be used not only as a blend oil component, but also as an aromatic product. In order to meet market demand and enhance product flexibility, some processes will produce part of toluene while producing non-aromatic and benzene in the reformed oil separation tower to remove Extractive distillation yields benzene and toluene products. In addition, a deheptanizer is added after the reformed oil separation tower. Toluene is extracted from the top of the deheptanizer as gasoline blending oil, and the bottom material of the toluene tower is sent to the xylene tower to obtain xylene products and blended gasoline components.

As the requirements for environmental protection are getting higher and higher, the requirements for the composition of gasoline at home and abroad are becoming more and more stringent. It has become a major trend to reduce the content of benzene and aromatics. The application proportion of reformed oil as a blending oil shows a downward trend, and the application of reformed oil as an aromatic product is gradually expanding. However, in recent years, with market fluctuations, the benefits of blended gasoline and aromatics products produced by reforming units are also prone to fluctuations. Timely adjustment of product lines to achieve the best economic benefits has become an important issue.

Considering the adjustability of products, some reforming and separation processes in actual production have added a deheptanizer. The depentanized oil is separated from the top of the reformed oil separation tower to separate non-aromatics, benzene and part of toluene, and the aromatics are extracted. The device obtains benzene and toluene products, the bottom material of the reformed oil separation tower goes to the deheptanizer, the remaining toluene is extracted from the top of the deheptanizer, and the bottom material goes to the xylene tower to obtain xylene products and blended gasoline components . Since toluene is an intermediate component, there is concentration back-mixing in the multi-tower separation process, resulting in an increase in energy consumption. At the same time, increasing the separation process of the deheptanizer has led to an increase in the number of equipment, large equipment investment, and high energy consumption for operation. Large area and other issues.

If the xylene separation tower in the above process is extracted from the bottom of the tower, due to the different raw materials, some devices may have the problem of high dry point of the blended gasoline material at the bottom of the tower or colloid. For this problem, there are two effective solutions in actual production. Option 1: Add a weight removal tower after the xylene tower to further remove heavy components to meet the dry point requirements of blended gasoline. Option 2: Increase gas phase side extraction at the bottom of the xylene tower, extract heavy components from the bottom of the tower, and extract blended gasoline materials that meet the dry point requirements from the side line. However, both solutions will lead to a substantial increase in energy consumption, increasing the energy consumption of the device and the equipment size of the xylene tower reboiler.

In recent years, with the comprehensive upgrading of safety and environmental protection requirements, more and more chemical companies are required to move into chemical industrial parks, and the demand for sites in the industrial parks is becoming more and more urgent. The limitation of floor area seriously affects and restricts the device construction and construction scale of enterprise devices.

Dividing Wall Column (DWC for short) rectification technology sets a vertical partition in the ordinary distillation column. The setting of the partition can make a single column realize the function of two columns and avoid the separation of intermediate components in the two-column process. Back mixing can reduce the mixing effect near the feed section and improve thermodynamic efficiency, so energy consumption can be greatly reduced. At the same time, adopting the dividing wall column technology can save a rectification column and auxiliary equipment, including condenser, reboiler, reflux tank, reflux pump, etc., reducing equipment investment and floor space. Therefore, the dividing wall tower is a process intensification technology that realizes double savings of energy saving and consumption reduction and equipment investment reduction.

Contents of the invention

Therefore, the technical problem to be solved by this invention is to provide a kind of dividing wall column rectification system for separating catalytic reforming depentanized oil, combining dividing wall column technology and multi-effect rectifying technology, to reduce separation catalytic reforming depentanized oil Energy consumption in the production process of paraffin oil, while reducing equipment investment.

In order to solve the above-mentioned technical problems, the present invention proposes a kind of dividing wall rectification system for separating catalytic reforming depentanized oil, comprising prefractionation tower T1 and xylene tower T2; The vertical partition B1 divides the pre-fractionation tower T1 into the first feed side F1 and the first discharge side S1, and the catalytically reformed depentanized oil 1 enters the first feed side F1 of the pre-fractionation tower T1. Fraction 2 rich in non-aromatics and benzene is extracted from the top of tower T1, and fraction 3 rich in toluene is extracted from the first discharge side S1 of pre-fractionation tower T1, and fraction 3 rich in toluene is extracted from the bottom of pre-fractionation tower T1, including xylene and recombinant The cut 4 of fractionation, is provided with heat exchanger E1 at the bottom of pre-fractionation tower T1, as the reboiler of pre-fractionation tower T1; The pipeline is connected with the pre-fractionation tower T1, the xylene product 5 is extracted from the top of the xylene column T2, and the heavy component 6 is extracted from the bottom of the xylene column T2.

Preferably, the heat source inlet of the heat exchanger E1 in the above-mentioned dividing wall column rectification system for separating catalytic reforming depentanized oil is connected to the top of the xylene tower T2, and the heat source outlet of the heat exchanger E1 is connected to the xylene The pipelines of the product 5 are connected, and the heat exchanger E1 is used as the condenser of the xylene column T2.

Preferably, a second vertical partition B2 is set in the xylene tower T2 in the above-mentioned dividing wall column rectification system for separating catalytic reforming depentanized oil, and the xylene tower T2 is divided into the second feed side F2 and The second discharge side S2, the second feed side F2 of the xylene tower T2 is connected to the pre-fractionation tower T1 through the pipeline comprising the fraction 4 of xylene and heavy components, and the xylene product 5 is extracted from the top of the xylene tower T2 , the discharge side S2 of the xylene tower T2 extracts a fraction 7 rich in C9 aromatics, and extracts a heavy component 6 from the bottom of the xylene tower T2.

Preferably, in the above-mentioned dividing wall column rectification system for separating catalytic reforming depentanized oil, the fraction 2 rich in non-aromatics and benzene extracted at the top of the pre-fractionation tower T1 is used as the fraction 2 extracted from aromatics Raw material, the toluene-rich fraction 3 extracted from the first discharge side S1 of the pre-fractionation tower T1 is used as the raw material of the blended gasoline.

Preferably, in the above-mentioned dividing wall column rectification system for separating catalytic reforming depentanized oil, the fraction 2 rich in non-aromatics and benzene extracted at the top of the pre-fractionation column T1 includes part of toluene. Specifically, the rectifying system of the dividing wall column can be switched between the following two preset working modes: in one preset working mode, the fraction 2 rich in non-aromatics and benzene is also Part of the toluene-rich fraction 3 is extracted, while in another preset working mode, only the toluene-rich fraction 3 is extracted from the first discharge side S1 of the pre-fractionator T1. The beneficial technical effect brought by this technical solution is that two working modes are provided to the user in a preset manner, and the user can decide whether to extract toluene as a blend oil component from the top of the pre-fractionating tower T1 or As the aromatics product, it is discharged from the first discharge side S1 of the pre-fractionation tower T1, so that the enterprise can flexibly respond to market demand.

Preferably, in the above-mentioned dividing wall column rectification system for separating catalytic reforming depentanized oil, the bottom of the pre-fractionation tower T1 extracts fraction 4 including xylene and heavy components, and after extraction and refining of aromatics , the pipeline comprising fraction 4 of xylene and heavy components is connected to the feed port of the xylene column T2.

Preferably, in the above-mentioned dividing wall column rectification system for separating catalytic reforming depentanized oil, the fraction 7 rich in C9 aromatics is used as a raw material for blended gasoline or as a raw material for downstream aromatics, and the heavy component 6 is used as diesel oil Or fuel oil.

Preferably, in the above-mentioned dividing wall column rectification system for separating catalytic reforming depentanized oil, the internal member forms of the pre-fractionation tower T1 and the xylene tower T2 can be tray towers, packed towers, tray towers Composite towers and packed towers, or other forms of internals.

The dividing wall column rectification system for separating catalytic reforming depentanized oil proposed by the present invention has the advantage that the prefractionating column in the present invention adopts the dividing wall column rectification technology, and simultaneously obtains aromatics extraction raw materials and can be used as blended gasoline The toluene-rich fraction of the raw material can greatly reduce energy consumption, the number of equipment is small, and the floor area is small, which can reduce equipment investment and operating costs; Heated by the heating device to form a double-effect rectification, which can achieve the purpose of further energy saving; the xylene tower adopts the rectification technology of the dividing wall column, and can also obtain xylene products and distillates rich in C9 aromatics at the same time.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and comprehensible from the description of the embodiments in conjunction with the following drawings, wherein:

Fig. 1 is a structural schematic diagram of an embodiment of a dividing wall column rectification system for separating catalytic reforming depentanized oil according to the present invention.

2 to 5 are different embodiments of the dividing wall column rectification system for separating catalytic reforming depentanized oil of the present invention.

Figures 6 to 8 respectively show the overall technical process of a traditional aromatics product separation process, an adjustable product separation process, and a method for separating catalytically reformed depentanized oil using a dividing wall column rectification system.

Detailed ways

The dividing wall tower rectification system that the present invention proposes is used for separating catalytic reforming depentanized oil, structure as shown in Figure 1, comprises prefractionation tower T1 and xylene tower T2; The partition B1 divides the pre-fractionation tower T1 into the first feed side F1 and the first discharge side S1, and the catalytically reformed depentanized oil 1 enters the first feed side F1 of the pre-fractionation tower T1, and in the pre-fractionation tower Fraction 2 rich in non-aromatics and benzene is extracted from the top of T1, fraction 3 rich in toluene is extracted from the first discharge side S1 of pre-fractionator T1, and fraction 3 rich in toluene is extracted from the bottom of pre-fractionator T1, including xylene and heavy components. The cut 4 of the pre-fractionation tower T1 is provided with a heat exchanger E1 at the bottom of the pre-fractionation tower T1 as a reboiler of the pre-fractionation tower T1; It is connected with the pre-fractionation tower T1, the xylene product 5 is extracted from the top of the xylene column T2, and the heavy component 6 is extracted from the bottom of the xylene column T2. The pre-fractionator T1 adopts the rectification technology of the dividing wall column, and at the same time obtains a fraction 2 rich in non-aromatics and benzene that can be used as a raw material for aromatics extraction and a fraction 3 rich in toluene that can be used as a raw material for blending gasoline, which can greatly reduce energy consumption. The number of equipment is small, and the floor area is small, which can reduce equipment investment and operating costs.

Fig. 2 shows a kind of variation embodiment of the rectification system of the dividing wall column for separating catalytic reforming depentanized oil, wherein the heating heat source inlet of the heat exchanger E1 is connected with the top of the xylene tower T2, and the heat exchanger The heat source outlet of E1 is connected with the pipeline of the xylene product 5, and the heat exchanger E1 is used as the condenser of the xylene column T2. In this embodiment, the pre-fractionation tower utilizes the latent heat condensed from the top vapor of the xylene tower to heat the reboiler to form a double-effect rectification, which can further save energy.

Fig. 3 shows a kind of variation embodiment on the basis of the embodiment described in Fig. 1 and Fig. 2 of the dividing wall column rectification system used for separating catalytic reforming depentanized oil, the first is set in the xylene tower T2 Two vertical partitions B2 divide the xylene tower T2 into a second feed side F2 and a second discharge side S2, and the second feed side F2 of the xylene tower T2 passes through a pipeline comprising a fraction 4 of xylene and heavy components Connected with the pre-fractionation tower T1, the xylene product 5 is extracted from the top of the xylene tower T2, the fraction 7 rich in C9 aromatics is extracted from the discharge side S2 of the xylene tower T2, and the heavy component is extracted from the bottom of the xylene tower T2 6. In this embodiment, the xylene column adopts the rectification technology of the dividing wall column, and can simultaneously obtain the xylene product and the fraction rich in C9 aromatics.

Fig. 4 shows a kind of embodiment different from the embodiment shown in Fig. 3 of the dividing wall column rectification system that is used for separating catalytic reforming depentanized oil, the heating heat source inlet of heat exchanger E1 wherein and xylene column The top of T2 is connected, the heat source outlet of heat exchanger E1 is connected with the pipeline of xylene product 5, and heat exchanger E1 is used as the condenser of xylene column T2. In this embodiment, two rectification towers with dividing walls are still used, which can greatly reduce energy consumption, reduce equipment investment and operating costs, and the pre-fractionation tower and xylene tower form a double-effect rectification, which can achieve the purpose of further energy saving.

In the above examples of the dividing wall column rectification system used for separation of catalytic reforming depentanized oil, the fraction 2 rich in non-aromatics and benzene is used as the raw material for aromatics extraction, and the fraction 3 rich in toluene is used as the blended gasoline raw material. The above embodiment can take into consideration the production of aromatics products and blended gasoline products from reformed oil.

More preferably, in the above embodiments of the dividing wall column rectification system for separating catalytic reforming depentanized oil, fraction 2 rich in non-aromatics and benzene includes part of toluene, and the aromatics of toluene can be flexibly adjusted according to market demand Ratio of extracting and deblending gasoline.

Fig. 5 shows another embodiment of the dividing wall column rectification system for separating catalytic reforming depentanized oil, wherein, the bottom of the pre-fractionation column T1 produces a fraction 4 including xylene and heavy components, including xylene And the fraction 4 of the heavy component is connected with the feed port of the xylene tower T2 through a pipeline after the aromatics are extracted and refined. In this example, after the bottom fraction of the pre-fractionation tower is extracted and refined by aromatics, non-aromatics such as C8 can be removed, thereby obtaining xylene product 5 with higher purity.

In the embodiment of the dividing wall column rectification system for separating catalytic reforming depentanized oil shown in Figure 3 and Figure 4, the xylene column adopts the dividing wall column, and the fraction rich in C9 aromatics extracted from the discharge side 7 is used as a raw material for blending gasoline or as a raw material for downstream aromatics, while the heavy component 6 is used as diesel or fuel oil. The xylene tower adopts a dividing wall tower, and the distillate rich in C9 aromatics is extracted from the discharge side as the raw material for blending gasoline, which can solve the problem of high dry point of gasoline blending oil extracted from the bottom of the ordinary distillation tower. The embodiment shown in Fig. 5 can also be combined with the embodiment shown in Fig. 3 or Fig. 4, and the bottom fraction of the prefractionation tower can be provided to the xylene tower T2 that the form is the dividing wall tower after being extracted and refined by aromatics, and can also be arbitrarily Optionally make the heating heat source inlet of the heat exchanger E1 link to each other with the top of the xylene tower T2, the heat source outlet of the heat exchanger E1 is connected with the pipeline of the xylene product 5, and the heat exchanger E1 is used as the condenser of the xylene tower T2, thereby The prefractionation tower T1 and the xylene tower T2 form a double-effect rectification.

The above-mentioned prefractionation tower T1 and the xylene tower T2 internal member form of the dividing wall tower rectification system for separating catalytic reforming depentanized oil can be a plate tower, a packed tower, a composite tower of a plate tower and a packed tower, or Other forms of internals.

In Fig. 6 to Fig. 8, the overall technical process of the traditional aromatics product separation process, the adjustable product separation process and the method for separating catalytically reformed depentanized oil with a dividing wall column rectification system according to the present invention are respectively shown.

Figure 6 shows a traditional aromatics product separation process. The depentanized oil raw material 101 is provided to the pre-fractionation tower T1, non-aromatics, benzene, and toluene 102 are extracted from the top of the tower, xylene and heavy components 104 are produced from the bottom of the tower, and xylene and heavy components 104 are delivered to the xylene Tower T2, xylene 105 is extracted from the top of the xylene tower T2, and the bottom product is removed from gasoline for blending 106.

Figure 7 shows an adjustable product separation process. The depentanized oil raw material 201 is also input to the pre-fractionation tower T1, and the aromatics, benzene, and toluene 202 are extracted from the top of the tower, and the toluene, xylene and heavy components 203 are produced from the bottom of the tower, and the xylene and heavy components 203 are transported To deheptanizer T3, extract crude toluene 207 at the top of deheptanizer T2 to blend gasoline, extract xylene and heavy components 204 at the bottom of deheptanizer T2, and the latter is transported to the second In the toluene tower T2, xylene 205 is extracted from the top of the xylene tower T2, gasoline blending components 206 are extracted from the outflow side, and diesel oil or fuel oil 208 is extracted from the bottom of the tower. It can be seen that in order to make the product adjustable, an additional deheptanizer needs to be arranged in the system.

Fig. 8 shows an embodiment of a method for separating catalytically reformed depentanized oil with a rectification system of a dividing wall column according to the present invention, in which two dividing wall columns and double-effect rectification are combined. The depentanized oil raw material 301 is input into the pre-fractionation tower T1, non-aromatics, benzene, and toluene 302 are extracted from the top of the tower to remove aromatics, crude toluene 303 is taken from the discharge side to blend gasoline, and xylene and heavy components are taken from the bottom of the tower 304, the latter is further separated in the xylene tower T2 into xylene 305 extracted from the top of the tower, C9 aromatics and heavy components 306 extracted from the discharge side to blend gasoline, and diesel oil or fuel oil 307. It can be seen from the comparison that the method of the present invention saves the deheptanizer and simultaneously realizes the adjustability of the product.

Although the embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and purpose of the present invention. , the scope of the present invention is defined by the claims and their equivalents.

List of reference signs

T1 Prefractionator

T2 xylene tower

E1 heat exchanger

F1 first feed side

S1 first discharge side

B1 first vertical partition

F2 second feed side

S2 second discharge side

B2 second vertical bulkhead

1 Catalytic reforming of depentanized oil

2 Fraction rich in non-aromatics and benzene

3 Fraction rich in toluene

4 Fraction including xylene and heavy components

5 xylene products

6 heavy components

7 Fraction rich in C9 aromatics

AED Aromatics Extraction

101 depentanized oil raw material

102 Non-aromatic, benzene, toluene

104 Xylene and heavy components

105 Xylene

106 Degasoline reconciliation

201 depentanized oil raw material

202 Non-aromatic, benzene, toluene

203 Toluene, xylene and heavy components

204 Xylene and heavy components

205 Xylene

206 gasoline blending components

207 crude toluene

208 Diesel or fuel oil

301 depentanized oil raw material

302 Non-aromatic, benzene, toluene

303 crude toluene

304 Xylene and heavy components

305 Xylene

306 C9 aromatic hydrocarbons and heavy components

307 Diesel or fuel oil.

Claims (10)

1. a kind of for separating the next door column rectification system of catalytic reforming de-pentane oil, which is characterized in that the next door tower rectifying system System includes prefractionator (T1) and benzenol hydrorefining (T2)；The first vertical partition plate (B1) is set in the prefractionator (T1), it will be pre- Fractionating column (T1) is divided into the first feed side (F1) and the first exit side (S1), and catalytic reforming de-pentane oil (1) enters prefractionator (T1) the first feed side (F1), at the top of prefractionator (T1), extraction is rich in the fraction (2) of non-aromatics and benzene, in prefractionation The first exit side (S1) extraction of tower (T1) is rich in the fraction (3) of toluene, and the bottom extraction of prefractionator (T1) includes dimethylbenzene And the fraction (4) of heavy constituent, it is equipped with heat exchanger (E1) in the bottom of prefractionator (T1), as boiling again for prefractionator (T1) Device；The feed inlet of the benzenol hydrorefining (T2) passes through pipeline and prefractionator including dimethylbenzene and the fraction (4) of heavy constituent (T1) it is connected, the top of benzenol hydrorefining (T2) produces xylene product (5), and the bottom of benzenol hydrorefining (T2) produces heavy constituent (6).

2. as described in claim 1 for separating the next door column rectification system of catalytic reforming de-pentane oil, which is characterized in that its Described in the heat source entrance of heat exchanger (E1) be connected with the top of benzenol hydrorefining (T2), the thermal source outlet of heat exchanger (E1) It is connected with the pipeline of xylene product (5), condenser of the heat exchanger (E1) as benzenol hydrorefining (T2).

3. as described in claim 1 for separating the next door column rectification system of catalytic reforming de-pentane oil, which is characterized in that institute It states in benzenol hydrorefining (T2) and the second vertical partition plate (B2) is set, benzenol hydrorefining (T2) is divided into the second feed side (F2) and second and is gone out Expect side (S2), the second feed side (F2) of benzenol hydrorefining (T2) by include dimethylbenzene and heavy constituent fraction (4) pipeline with Prefractionator (T1) is connected, and produces xylene product (5) at the top of benzenol hydrorefining (T2), the exit side of benzenol hydrorefining (T2) (S2) extraction is rich in the fraction (7) of C9 aromatic hydrocarbons, and the bottom of benzenol hydrorefining (T2) produces heavy constituent (6).

4. as described in claim 1 for separating the next door column rectification system of catalytic reforming de-pentane oil, which is characterized in that Raw material of the fraction (2) rich in non-aromatics and benzene of the top extraction of the prefractionator (T1) as Aromatics Extractive Project, Raw material of the fraction (3) as blended gasoline rich in toluene of the first exit side (S1) extraction of the prefractionator (T1).

5. as described in claim 1 for separating the next door column rectification system of catalytic reforming de-pentane oil, which is characterized in that The fraction (2) rich in non-aromatics and benzene of the top extraction of the prefractionator (T1) includes part toluene.

6. as described in claim 1 for separating the next door column rectification system of catalytic reforming de-pentane oil, which is characterized in that pre- The bottom extraction of fractionating column (T1) includes the fraction (4) of dimethylbenzene and heavy constituent, after Aromatics Extractive Project refines, including dimethylbenzene And the pipeline of the fraction (4) of heavy constituent is connected with the feed inlet of the benzenol hydrorefining (T2).

7. as described in claim 1 for separating the next door column rectification system of catalytic reforming de-pentane oil, which is characterized in that institute Raw material of the fraction (7) as blended gasoline rich in C9 aromatic hydrocarbons or the raw material as downstream aromatic hydrocarbons are stated, heavy constituent (6) is used as diesel oil Or fuel oil.

8. a kind of method with next door column rectification system separation catalytic reforming de-pentane oil, the next door column rectification system include pre- Fractionating column (T1) and benzenol hydrorefining (T2)；The first vertical partition plate (B1) is set in the prefractionator (T1), by prefractionator (T1) it is divided into the first feed side (F1) and the first exit side (S1), the feed inlet of the benzenol hydrorefining (T2) directly or indirectly leads to The pipeline for crossing the fraction (4) including dimethylbenzene and heavy constituent is connected with prefractionator (T1),

It is characterized in that, catalytic reforming de-pentane oil (1) enters first feed side (F1) of prefractionator (T1), in prefractionator (T1) top extraction is rich in the fraction (2) of non-aromatics and benzene, is rich in the first exit side (S1) extraction of prefractionator (T1) The fraction (3) of toluene, the bottom extraction of prefractionator (T1) they include the fraction (4) of dimethylbenzene and heavy constituent, also,

The fraction (4) including dimethylbenzene and heavy constituent is supplied by pipeline to the feed inlet of the benzenol hydrorefining (T2), institute Top extraction xylene product (5) of benzenol hydrorefining (T2) is stated, the bottom of benzenol hydrorefining (T2) produces heavy constituent (6).

9. as claimed in claim 8 with the method for next door column rectification system separation catalytic reforming de-pentane oil, wherein described The heat source entrance of heat exchanger (E1) is connected with the top of benzenol hydrorefining (T2), the thermal source outlet and dimethylbenzene of heat exchanger (E1) The pipeline of product (5) is connected, condenser of the heat exchanger (E1) as benzenol hydrorefining (T2).

10. as claimed in claim 8 or 9 with the method for next door column rectification system separation catalytic reforming de-pentane oil, wherein institute It states in benzenol hydrorefining (T2) and the second vertical partition plate (B2) is set, benzenol hydrorefining (T2) is divided into the second feed side (F2) and second and is gone out Expect side (S2), the second feed side (F2) of benzenol hydrorefining (T2) by include dimethylbenzene and heavy constituent fraction (4) pipeline with Prefractionator (T1) is connected,

It is characterized in that, xylene product (5) are produced at the top of benzenol hydrorefining (T2), the exit side (S2) of benzenol hydrorefining (T2) Extraction is rich in the fraction (7) of C9 aromatic hydrocarbons, and the bottom of benzenol hydrorefining (T2) produces heavy constituent (6).