Processing system for producing light aromatic hydrocarbon from medium-temperature coal tar

Abstract

The utility model relates to the technical field of coal tar processing equipment, and discloses a processing system for producing light aromatic hydrocarbon from medium-temperature coal tar, which comprises a decarburization device, a naphtha extraction device and a light aromatic hydrocarbon extraction device which are sequentially arranged from front to back along the processing flow direction, through a naphtha extraction device, coked oil gas is separated to form naphtha fractions and bottom recycle oil, the bottom recycle oil flows back to be mixed with medium-temperature coal tar to form a first raw material, the first raw material enters a decarburization device to be separated to form coked oil gas, and a second raw material is subjected to fractionation in a light aromatic hydrocarbon extraction device to form light aromatic hydrocarbon and raffinate oil; the raffinate oil flows back to be mixed with the naphtha fraction to form the second raw material; according to the processing system for producing the light aromatic hydrocarbon from the medium-temperature coal tar, the naphtha fraction is directly used as an aromatization raw material to obtain a light aromatic hydrocarbon product, a naphtha reforming process is not involved, and the product bottom cycle oil and raffinate oil in the process flow are used as production raw materials, so that the production cost is further reduced, and the productivity is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to coal tar processing equipment technical field, concretely relates to a processing system that light aromatic hydrocarbon is produced to medium temperature coal tar. BACKGROUND

[0002] Coal tar is a liquid byproduct produced in the process of deep processing of coal, has pungent smell, and can be divided into low temperature coal tar, medium temperature coal tar and high temperature coal tar according to different pyrolysis temperature. Coal tar is complex, contains a large amount of condensed ring aromatic hydrocarbon and S, N, O and other heteroatoms and metal and other non-hydrocarbon compounds, and is mainly processed and utilized by hydrogenation process at present. Coal tar hydrogenation technology is the most reasonable and effective key technology. Coal tar hydrogenation upgrading process can be roughly divided into two parts: hydrofining and hydrocracking. The hydrofining part is mainly to remove sulfur, nitrogen, oxygen, heavy metal and other impurity molecules in coal tar, is the main reaction of coal tar hydrogenation upgrading process, and the quality of hydrofining determines whether the product meets the subsequent production requirements. The purpose of hydrocracking is to generate light fuel oil under the action of high temperature and high pressure, catalyst and hydrogen, such as alkane cracking, naphthene cracking and aromatic cracking. At present, medium temperature coal tar is mainly produced by combining hydrofining and hydrocracking to produce aromatic hydrocarbon, realizing efficient utilization of coal tar resources.

[0003] In the prior art, the main products of the medium temperature coal tar lightening project are naphtha fraction and diesel fraction, the diesel fraction accounts for more than 75%, and the naphtha fraction is not further treated, so that the economic benefit of the product is low. The light aromatic hydrocarbon in the coal tar hydrogenation product is not effectively separated and purified, and the added value of the product is low. UTILITY MODEL CONTENT

[0004] Therefore, the utility model provides a processing system that light aromatic hydrocarbon is produced to medium temperature coal tar to realize effective separation and purification of light aromatic hydrocarbon in coal tar and improve the added value of the product.

[0005] To solve the above technical problem, the technical scheme of the utility model is as follows:

[0006] The utility model provides a kind of processing system of medium temperature coal tar production light aromatic hydrocarbon, comprising: decarburization device, naphtha extraction device and light aromatic hydrocarbon extraction device are sequentially arranged from front to back along the processing flow direction;First raw material enters the decarburization device, the decarburization device carries out light weight treatment to the first raw material to form coking oil gas, the coking oil gas is introduced into the naphtha extraction device;The front and rear ends of the naphtha extraction device are respectively communicated with the decarburization device and the light aromatic hydrocarbon extraction device, the naphtha extraction device is suitable for the coking oil gas fractionation to form naphtha fraction and bottom oil, the bottom oil backflow to the front end of the decarburization device and medium temperature coal tar are mixed to form the first raw material, the naphtha fraction is introduced into the light aromatic hydrocarbon extraction device;Second raw material is fractionated in the light aromatic hydrocarbon extraction device to form light aromatic hydrocarbon and raffinate oil, and the raffinate oil backflow to the front end of the light aromatic hydrocarbon extraction device to be mixed with the naphtha to form the second raw material.

[0007] It has the advantages that: through the naphtha extraction device, the coking oil gas is separated to form naphtha fraction and bottom oil, the bottom oil backflow to be mixed with medium temperature coal tar to form the first raw material, the first raw material enters the decarburization device to be separated to form coking oil gas, the second raw material is fractionated in the light aromatic hydrocarbon extraction device to form light aromatic hydrocarbon and raffinate oil, and the raffinate oil backflow to be mixed with the naphtha fraction to form the second raw material;The processing system of medium temperature coal tar production light aromatic hydrocarbon directly uses naphtha fraction as aromatization raw material to obtain light aromatic hydrocarbon product, reduces naphtha reforming process, and the product bottom oil and raffinate oil in process flow are used as production raw material, to further reduce production cost and improve production capacity.

[0008] According to some embodiments of the utility model, the decarburization device is a delayed coking device, the decarburization device includes a coking tower, the coking tower is provided with a first feed inlet, a first discharge end and a second discharge end, the first raw material enters the coking tower through the first feed inlet, the first raw material forms the coking oil gas and the pitch coke in the coking tower, the coking oil gas flows out from the first discharge end, and the pitch coke flows out from the second discharge end.

[0009] According to some embodiments of the utility model, the naphtha extraction device includes first fractionating structure, hydrogenation refining structure and second fractionating structure which are sequentially arranged from front to back along the processing flow direction;

[0010] The first fractionating structure is provided with a second feed inlet, a third discharge end and a fourth discharge end, the first discharge end is communicated with the second feed inlet, the fourth discharge end is communicated with the first feed inlet, the coking oil gas is fractionated in the first fractionating structure to form mixed fraction oil and the bottom oil, the bottom oil backflow to the first feed inlet through the fourth discharge end to be mixed with medium temperature coal tar to form the first raw material;

[0011] The mixed distillate oil is separated into a naphtha fraction and a tail oil in the second fractionation structure.

[0012] According to some embodiments of the present application, the first fractionation structure is further provided with a fifth discharge end, and the coking oil gas is separated into a phenol oil in the first fractionation structure and discharged from the fifth discharge end.

[0013] According to some embodiments of the present application, the fifth discharge end, the third discharge end and the fourth discharge end are sequentially arranged from top to bottom along the height direction of the first fractionation structure.

[0014] According to some embodiments of the present application, the naphtha extraction device further comprises a hydrocracking structure arranged at the rear end of the second fractionation structure.

[0015] The hydrofining structure is provided with a third feed inlet and a sixth discharge end, the third discharge end is communicated with the third feed inlet, the mixed distillate oil is separated into a hydrofining oil in the hydrofining structure and flows out from the sixth discharge end.

[0016] The second fractionation structure is provided with a fourth feed inlet, a seventh discharge end and an eighth discharge end, the fourth feed inlet is communicated with the sixth discharge end, the seventh discharge end is communicated with the light aromatic hydrocarbon extraction device, and the eighth discharge end is communicated with the hydrocracking structure.

[0017] The third raw material is separated into a naphtha fraction and a tail oil in the second fractionation structure through the fourth feed inlet, the tail oil enters the hydrocracking structure through the eighth discharge end to produce a hydrocracking oil, the hydrocracking oil is mixed with the hydrofining oil to form the third raw material, and the naphtha fraction enters the light aromatic hydrocarbon extraction device through the seventh discharge end.

[0018] According to some embodiments of the present application, the second fractionation structure is further provided with a ninth discharge end, and the third raw material is separated into a diesel oil fraction in the second fractionation structure and discharged from the ninth discharge end.

[0019] According to some embodiments of the present application, along the height direction of the second fractionation structure, the seventh discharge end, the ninth discharge end and the eighth discharge end are sequentially arranged from top to bottom.

[0020] According to some embodiments of the present application, the hydrocracking structure comprises a fifth feed inlet and a tenth discharge end, the fifth feed inlet is communicated with the eighth discharge end, the tail oil enters the hydrocracking structure through the feed inlet and the eighth discharge end, and the hydrocracking oil is returned to the front end of the second fractionation structure from the tenth discharge end after being generated, and is mixed with the hydrofining oil to form the third raw material.

[0021] According to some embodiments of the present application, the light aromatic hydrocarbon extraction device comprises an aromatization structure and an aromatic hydrocarbon extraction distillation structure.

[0022] The aromatization structure is provided with the sixth feed inlet and the eleventh discharge end, the seventh discharge end and the sixth feed inlet are communicated, the second raw material flows into the aromatization structure through the sixth feed inlet and forms aromatization oil;

[0023] The aromatic hydrocarbon extraction distillation structure is provided with a seventh feed inlet, a twelfth discharge end and a thirteenth discharge end, the seventh feed inlet is communicated with the eleventh discharge end, the aromatization oil flows through the eleventh discharge end to form light aromatic hydrocarbon and the raffinate oil in the aromatic hydrocarbon extraction distillation structure, the raffinate oil flows through the thirteenth discharge end and returns to the front end of the sixth feed inlet to mix with the naphtha fraction to form the second raw material, and the light aromatic hydrocarbon flows out through the twelfth discharge end. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the drawings needed in the specific embodiments or prior art description will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0025] Figure 1 It is a processing flow diagram of a processing system for producing light aromatic hydrocarbon from medium temperature coal tar according to an embodiment of the present application.

[0026] BRIEF DESCRIPTION OF DRAWINGS

[0027] 1, decarburization device; 2, first fractionation structure; 3, hydrofining structure; 4, second fractionation structure; 5, hydrocracking structure; 6, aromatization structure; 7, aromatic hydrocarbon extraction distillation structure; 11, first feed inlet; 12, first discharge end; 13, second discharge end; 21, second feed inlet; 22, third discharge end; 23, fourth discharge end; 24, fifth discharge end; 31, third feed inlet; 32, sixth discharge end; 41, fourth feed inlet; 42, seventh discharge end; 43, eighth discharge end; 44, ninth discharge end; 51, fifth feed inlet; 52, tenth discharge end; 61, sixth feed inlet; 62, eleventh discharge end; 71, seventh feed inlet; 72, twelfth discharge end; 73, thirteenth discharge end. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in combination with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the utility model.

[0029] In the description of the utility model, it should be explained that the orientation or position relation indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like is based on the orientation or position relation shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and therefore cannot be understood as limiting the utility model. In addition, the terms "first", "second" and "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0030] In the description of the utility model, it should be explained that, unless otherwise explicitly specified and limited, the terms "mounting", "connection" and "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the communication inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0031] In addition, the technical features involved in the different embodiments of the utility model described below can be combined with each other as long as there is no conflict between them.

[0032] Referring to Figure 1 As shown in the utility model provides a kind of processing system of medium temperature coal tar production light aromatic hydrocarbon, comprising: decarburization device 1, naphtha extraction device and light aromatic hydrocarbon extraction device are sequentially arranged from front to back along the processing flow direction;First raw material enters decarburization device 1, decarburization device 1 is lightened to form coking oil gas to the first raw material, and coking oil gas is introduced into naphtha extraction device;The front and rear ends of naphtha extraction device are communicated with decarburization device 1 and light aromatic hydrocarbon extraction device respectively, and naphtha extraction device is suitable for coking oil gas fractionation to form naphtha fraction and bottom cycle oil, bottom cycle oil backflow to the front end of decarburization device 1 and mix with medium temperature coal tar to form first raw material, and naphtha fraction is introduced into light aromatic hydrocarbon extraction device;Second raw material is fractionated to form light aromatic hydrocarbon and raffinate oil in light aromatic hydrocarbon extraction device, and raffinate oil backflow to the front end of light aromatic hydrocarbon extraction device to mix with naphtha to form second raw material.

[0033] Specifically, the coking oil gas is separated by the naphtha extraction device to form a naphtha fraction and a bottom oil, the bottom oil is refluxed to be mixed with the medium temperature coal tar to form the first raw material, the first raw material enters the decarburization device 1 to be separated to form the coking oil gas, the second raw material is fractionated in the light aromatic hydrocarbon extraction device to form light aromatic hydrocarbons and raffinate oil, the raffinate oil is refluxed to be mixed with the naphtha fraction to form the second raw material; the processing system for producing light aromatic hydrocarbons from the medium temperature coal tar directly uses the naphtha fraction as an aromatization raw material to obtain the light aromatic hydrocarbon product, reduces the naphtha reforming process, and uses the product bottom oil and the raffinate oil in the process as production raw materials to further reduce the production cost and improve the production capacity.

[0034] In some embodiments of the utility model, the decarburization device 1 is a delayed coking device, the decarburization device 1 includes a coking tower, the coking tower is equipped with a first feed inlet 11, a first discharge end 12 and a second discharge end 13, the first raw material enters the coking tower through the first feed inlet 11, the first raw material forms coking oil gas and pitch coke in the coking tower, the coking oil gas flows out from the first discharge end 12, and the pitch coke flows out from the second discharge end 13.

[0035] Specifically, the decarburization device 1 is used for lightening treatment of the medium temperature coal tar, removes heavy components such as colloid pitch and mechanical impurities, and improves the liquid product yield. Since the density of the coking oil gas is less than the density of the pitch coke, the first discharge end 12 is arranged at the top of the coking tower, and the second discharge end 13 is arranged at the bottom of the coking tower, so that the coking oil gas and the pitch coke are separated.

[0036] In some embodiments of the utility model, the naphtha extraction device includes a first fractionating structure 2, a hydrogenation refining structure 3 and a second fractionating structure 4 arranged in sequence from front to back along the processing flow direction; the first fractionating structure 2 is equipped with a second feed inlet 21, a third discharge end 22 and a fourth discharge end 23, the first discharge end 12 is communicated with the second feed inlet 21, the fourth discharge end 23 is communicated with the first feed inlet 11, the coking oil gas is fractionated in the first fractionating structure 2 to form mixed fraction oil and bottom oil, the bottom oil is refluxed to the first feed inlet 11 through the fourth discharge end 23 to be mixed with the medium temperature coal tar to form the first raw material; and the mixed fraction oil passes through the hydrogenation refining structure 3 and the second fractionating structure 4 to form the naphtha fraction.

[0037] Specifically, the first fractionating structure 2 is used for separating oxygen-containing compounds (mainly phenolic compounds) in the coking oil gas to be used as a phenol extraction raw material and to provide production raw materials for hydrogenation refining; the hydrogenation refining structure 3 is used to remove O, S, N heteroatoms and trace metal elements contained in the mixed fraction to obtain hydrogenation refined products; and the second fractionating structure 4 is used for separating the third raw material into a naphtha fraction, a diesel fraction and a tail oil fraction to provide raw materials for the light aromatic hydrocarbon extraction device.

[0038] In some embodiments of the utility model, first fractionating structure 2 still is provided with fifth discharge end 24, coking oil gas separates to form phenol oil in first fractionating structure 2, and is discharged from fifth discharge end 24.

[0039] In some embodiments of the utility model, fifth discharge end 24, third discharge end 22 and fourth discharge end 23 are sequentially arranged from top to bottom along the height direction of first fractionating structure 2.

[0040] Specifically, according to the density of naphtha fraction, diesel fraction and tail oil, fifth discharge end 24, third discharge end 22 and fourth discharge end 23 are sequentially arranged from top to bottom along the height direction of first fractionating structure 2, so as to facilitate the separation and extraction of each component.

[0041] In some embodiments of the utility model, the naphtha extraction device further comprises a hydrocracking structure 5 arranged at the rear end of the second fractionating structure 4; the hydrofining structure 3 is provided with a third feed inlet 31 and a sixth discharge end 32, the third discharge end 22 is communicated with the third feed inlet 31, the mixed distillate oil enters the hydrofining structure 3 to be fractionated to form hydrofining oil, and flows out from the sixth discharge end 32; the second fractionating structure 4 is provided with a fourth feed inlet 41, a seventh discharge end 42 and an eighth discharge end 43, the fourth feed inlet 41 is communicated with the sixth discharge end 32, the seventh discharge end 42 is communicated with the light aromatic hydrocarbon extraction device, and the eighth discharge end 43 is communicated with the hydrocracking structure 5; the third raw material enters the second fractionating structure 4 through the fourth feed inlet 41 to be fractionated to form naphtha fraction and tail oil, the tail oil enters the hydrocracking structure 5 through the eighth discharge end 43 to produce hydrocracking oil, the hydrocracking oil is mixed with the hydrofining oil to form the third raw material; the naphtha fraction enters the light aromatic hydrocarbon extraction device through the seventh discharge end 42.

[0042] Specifically, the hydrocracking device is used for performing lightening treatment on the tail oil fraction of the second fractionating device.

[0043] In some embodiments of the utility model, the second fractionating structure 4 is further provided with a ninth discharge end 44, and the third raw material is fractionated in the second fractionating structure 4 to form a diesel fraction, which is discharged from the ninth discharge end 44.

[0044] Specifically, the diesel fraction is used as the feed of the diesel adsorption separation device outside the system.

[0045] In some embodiments of the utility model, along the height direction of the second fractionating structure 4, the seventh discharge end 42, the ninth discharge end 44 and the eighth discharge end 43 are sequentially arranged from top to bottom.

[0046] In some embodiments of the utility model, hydrogenation cracking structure 5 includes fifth feed port 51 and tenth discharge end 52, fifth feed port 51 is communicated with eighth discharge end 43, tail oil enters hydrogenation cracking structure 5 through feed port and eighth discharge end 43, after generating hydrogenation cracking oil, from tenth discharge end 52 back flow to the front end of second fractionating structure 4, and mixes with hydrogen refined oil to form third raw material.

[0047] In some embodiments of the utility model, light aromatic hydrocarbon extraction device includes aromatization structure 6 and aromatic hydrocarbon extraction rectification structure 7;

[0048] Aromatization structure 6 is equipped with sixth feed port 61 and eleventh discharge end 62, seventh discharge end 42 and sixth feed port 61 are communicated, and second raw material flows through sixth feed port 61 and enters aromatization structure 6 and forms aromatization oil;

[0049] Aromatic hydrocarbon extraction rectification structure 7 is equipped with seventh feed port 71, twelfth discharge end 72 and thirteenth discharge end 73, seventh feed port 71 and eleventh discharge end 62 are communicated, and aromatization oil flows through eleventh discharge end 62 and forms light aromatic hydrocarbon and raffinate oil in aromatic hydrocarbon extraction rectification structure 7, raffinate oil flows through thirteenth discharge end 73 and back flows to the front end of sixth feed port 61 to mix with naphtha fraction and form second raw material, and light aromatic hydrocarbon flows out through twelfth discharge end 72.

[0050] Specifically, aromatization structure 6 is used for aromatization treatment to naphtha fraction, and aromatic hydrocarbon extraction rectification structure 7 is used for separating benzene, toluene, xylene products and raffinate oil through extraction and rectification to the aromatic hydrocarbon-rich liquid, and the raffinate oil is mixed with naphtha fraction as the raw material of aromatization structure.

[0051] Although the embodiments of the utility model are described in combination with the drawings, various modifications and variations can be made by those skilled in the art without departing from the spirit and scope of the utility model, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A processing system for the production of light aromatic hydrocarbons from medium temperature coal tar, characterized by, The application relates to a naphtha extraction device and a light aromatic hydrocarbon extraction device. A first raw material enters the decarburization device (1), the decarburization device (1) performs lightening treatment on the first raw material to form coking oil gas, and the coking oil gas enters the naphtha extraction device; The front end and the rear end of the naphtha extraction device are communicated with the decarburization device (1) and the light aromatic hydrocarbon extraction device respectively, the naphtha extraction device is suitable for fractionating the coking oil gas to form a naphtha fraction and a bottom oil, the bottom oil is returned to the front end of the decarburization device (1) and mixed with medium-temperature coal tar to form the first raw material, and the naphtha fraction enters the light aromatic hydrocarbon extraction device. A second raw material is fractionated in the light aromatic hydrocarbon extraction device to form light aromatic hydrocarbons and raffinate oil, and the raffinate oil is returned to the front end of the light aromatic hydrocarbon extraction device to be mixed with the naphtha to form the second raw material. The decarburization device (1) is a delayed coking device, the decarburization device (1) comprises a coking tower which is provided with a first feeding port (11), a first discharging end (12) and a second discharging end (13), the first raw material enters the coking tower through the first feeding port (11), the first raw material forms coking oil gas and pitch coke in the coking tower, the coking oil gas flows out from the first discharging end (12), and the pitch coke flows out from the second discharging end (13).

2. The medium temperature coal tar processing system for producing light aromatic hydrocarbons according to claim 1, characterized in that, The naphtha extraction device comprises a first fractionating structure (2), a hydrogenation refining structure (3) and a second fractionating structure (4) which are sequentially arranged along the processing flow direction from front to back.

3. The medium temperature coal tar processing system for producing light aromatic hydrocarbons according to claim 2, characterized in that, The first fractionating structure (2) is provided with a second feeding port (21), a third discharging end (22) and a fourth discharging end (23), the first discharging end (12) is communicated with the second feeding port (21), the fourth discharging end (23) is communicated with the first feeding port (11), the coking oil gas is fractionated in the first fractionating structure (2) to form mixed fraction oil and the bottom oil, the bottom oil is returned to the first feeding port (11) through the fourth discharging end (23) to be mixed with medium-temperature coal tar to form the first raw material, The mixed fraction oil passes through the hydrogenation refining structure (3) and the second fractionating structure (4) to form a naphtha fraction. The first fractionating structure (2) is further provided with a fifth discharging end (24), the coking oil gas is separated in the first fractionating structure (2) to form phenol oil which is discharged from the fifth discharging end (24).

4. The medium temperature coal tar processing system for producing light aromatic hydrocarbons according to claim 3, characterized in that, The fifth discharging end (24), the third discharging end (22) and the fourth discharging end (23) are sequentially arranged from top to bottom along the height direction of the first fractionating structure (2).

5. The medium temperature coal tar processing system for producing light aromatic hydrocarbons according to claim 4, characterized in that, The naphtha extraction device further comprises a hydrocracking structure (5) arranged at the rear end of the second fractionating structure (4).

6. The medium temperature coal tar processing system for producing light aromatic hydrocarbons according to claim 3, characterized in that, ​ The hydrofining structure (3) is provided with a third feed inlet (31) and a sixth discharge end (32), the third discharge end (22) communicates with the third feed inlet (31), the mixed distillate enters the hydrofining structure (3) to be fractionated to form hydrofining oil, and flows out from the sixth discharge end (32); The second fractionating structure (4) is provided with a fourth feed inlet (41), a seventh discharge end (42) and an eighth discharge end (43), the fourth feed inlet (41) communicates with the sixth discharge end (32), the seventh discharge end (42) communicates with the light aromatic hydrocarbon extraction device, and the eighth discharge end (43) communicates with the hydrocracking structure (5); The third raw material enters the second fractionating structure (4) through the fourth feed inlet (41) to be fractionated to form a naphtha fraction and tail oil, the tail oil enters the hydrocracking structure (5) through the eighth discharge end (43) to produce hydrocracking oil, and the hydrocracking oil is mixed with the hydrofining oil to form the third raw material; the naphtha fraction enters the light aromatic hydrocarbon extraction device through the seventh discharge end (42).

7. The medium temperature coal tar processing system for producing light aromatic hydrocarbons according to claim 6, characterized in that, The second fractionating structure (4) is further provided with a ninth discharge end (44), the third raw material is fractionated in the second fractionating structure (4) to form a diesel fraction, and is discharged from the ninth discharge end (44).

8. The medium temperature coal tar processing system for producing light aromatic hydrocarbons according to claim 7, characterized in that, Along the height direction of the second fractionating structure (4), the seventh discharge end (42), the ninth discharge end (44) and the eighth discharge end (43) are sequentially arranged from top to bottom.

9. The medium temperature coal tar processing system for producing light aromatic hydrocarbons according to claim 6, characterized in that, The hydrocracking structure (5) comprises a fifth feed inlet (51) and a tenth discharge end (52), the fifth feed inlet (51) communicates with the eighth discharge end (43), the tail oil enters the hydrocracking structure (5) through the feed inlet and the eighth discharge end (43), and after the hydrocracking oil is generated, it flows back to the front end of the second fractionating structure (4) from the tenth discharge end (52) and is mixed with the hydrofining oil to form the third raw material.

10. The medium temperature coal tar processing system for producing light aromatic hydrocarbons according to claim 9, characterized in that, The light aromatic hydrocarbon extraction device comprises an aromatization structure (6) and an aromatic hydrocarbon extraction rectification structure (7); The aromatization structure (6) is provided with a sixth feed inlet (61) and an eleventh discharge end (62), the seventh discharge end (42) communicates with the sixth feed inlet (61), and the second raw material flows into the aromatization structure (6) through the sixth feed inlet (61) and forms aromatization oil; The aromatic hydrocarbon extraction rectification structure (7) is provided with a seventh feed inlet (71), a twelfth discharge end (72) and a thirteenth discharge end (73), the seventh feed inlet (71) communicates with the eleventh discharge end (62), the aromatization oil flows through the eleventh discharge end (62) in the aromatic hydrocarbon extraction rectification structure (7) to form light aromatic hydrocarbon and the raffinate, the raffinate flows back to the front end of the sixth feed inlet (61) through the thirteenth discharge end (73) to be mixed with the naphtha fraction to form the second raw material, and the light aromatic hydrocarbon flows out through the twelfth discharge end (72).

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