Equipment and process for enriching aromatics from the mesophase of medium and low temperature coal tar

Abstract

The present invention provides a medium and low temperature coal tar mesophase enriched aromatics equipment and process, and its process includes steps a and b, step a separation obtains light distillate oil-II based on paraffin, and this component is mixed with the light distillate oil-I obtained by distillation and modulated to be sold as light oil; the light phenol oil obtained by separation in step b and the enriched refined aromatics are high value-added fine chemicals. From the perspective of graded utilization, different high-value fine chemicals such as alkoxyphenols, naphthalene, alkylnaphthalene, anthracene, pyrene, benzo[ghi]perylene, etc. can be obtained by pressurized gradient column chromatography and fractional recrystallization. The present invention is operated under mild conditions, and the solvent used is recycled, with the characteristics of green and efficient, low energy consumption, low investment cost, etc., overcomes the shortcomings of traditional process production of condensed aromatics, such as long route, easy to produce secondary pollution, high production cost, and effectively enriches the source of condensed aromatics fine chemicals.

Description

Technical Field

[0001] The present invention relates to the technical field of coal chemical industry, and in particular to a device and process for enriching aromatic hydrocarbons in a mesophase of medium- and low-temperature coal tar. Background Art

[0002] Medium- and low-temperature coal tar is a byproduct obtained during the medium- and low-temperature dry distillation of long flame coal to produce semi-coke (lignite) or through reforming. Its organic components are rich in aromatics, alkanes, alkenes, and heteroatom-containing organic compounds. With the development and upgrading of the regional coal chemical industry, the annual output of medium- and low-temperature coal tar has been increasing year by year. In short, the organic components of medium- and low-temperature coal tar are a valuable source of various fine chemical intermediates and high-value end products in chemical production. However, existing deep processing of medium- and low-temperature coal tar primarily involves distillation, catalytic hydrogenation, and carbonization. The resulting products are primarily light fractions (gasoline and diesel), heavy fractions (fuel, paving asphalt, etc.), and carbon materials (needle coke, graphite electrodes, etc.), with overall low added value. To further accelerate the high-quality development of the regional energy industry and promote the construction of energy industry revolution demonstration zones, there is an urgent need to optimize the utilization of medium- and low-temperature coal tar based on its molecular composition and component properties.

[0003] Due to the inherent quenching production process of medium and low-temperature coal tar, carbon and inorganic matter particles of different sizes are present in its system, seriously affecting the product quality of subsequent fine chemicals such as aromatics. However, it is very difficult to remove tiny particles in the existing separation process, and the process flow is cumbersome. Summary of the Invention

[0004] To address the above-mentioned drawbacks, the present invention provides a medium- and low-temperature coal tar mesophase enrichment equipment and process for aromatics. The present invention operates under mild conditions, and the solvents used are recycled. It has the characteristics of being green, efficient, low in energy consumption, and low in investment cost. It overcomes the shortcomings of traditional processes for producing condensation aromatics, such as a long route, easy generation of secondary pollution, and high production costs, and effectively enriches the source of condensation aromatic fine chemicals.

[0005] In a first aspect, the present invention provides a medium-low temperature coal tar intermediate phase enrichment aromatic hydrocarbon equipment, which comprises a raw material tank I (12), a primary extraction kettle (5), an alkane storage tank (10), a condenser I (15), an alkane buffer tank (17), a secondary extraction kettle (6), a raw material tank II (13), a raw material tank III (14), a condenser II (16), a graded solvent storage tank (11) and a phase separation tank (18); the outlet of the raw material tank I (12) is connected to the inlet of the primary extraction kettle (5) through a pipeline, the first outlet of the primary extraction kettle (5) is connected to the inlet of the secondary extraction kettle (6) through a pipeline, the outlet of the primary extraction kettle (5) is connected to the inlet of the condenser I (15) through a pipeline, and the outlet of the condenser I (15) is connected to the alkane buffer tank (17). The inlet of the tank (17) is connected through a pipeline, the outlet of the alkane buffer tank (17) is connected to the inlet of the alkane storage tank (10) through a pipeline, and the outlet of the alkane storage tank (10) is connected to the inlet of the primary extraction kettle (5) through a pipeline; the outlets of the raw material tank II (13) and the raw material tank III (14) are both connected to the inlet of the secondary extraction kettle (6) through a pipeline, the outlet of the secondary extraction kettle (6) is connected to the inlet of the condenser II (16) through a pipeline, the outlet of the condenser II (16) is connected to the inlet of the phase separation tank (18) through a pipeline, the outlet of the phase separation tank (18) is connected to the inlet of the graded solvent storage tank (11) through a pipeline, and the outlet of the graded solvent storage tank (11) is connected to the inlet of the secondary extraction kettle (6) through a pipeline.

[0006] In one embodiment of the present invention, a discharge valve I (26) is provided at the bottom of the first-stage extraction kettle (5), an electric auxiliary heating device and an ultrasonic radiation device are provided on the outer wall of the first-stage extraction kettle (5), the electric auxiliary heating device and the ultrasonic radiation device are respectively connected to the magnetic thermal controller I (3), a motor I (42), a pressure gauge I (22) and a vent valve III (34) are provided on the top of the first-stage extraction kettle (5), and a stirrer I (23) is provided in the middle of the first-stage extraction kettle (5), and the stirrer I (23) is connected to the motor I (42).

[0007] In one embodiment of the present invention, the primary extraction kettle (5) is connected to the feeding device via a pipeline, and a liquid valve I (36) is provided on the pipeline between the primary extraction kettle (5) and the feeding device;

[0008] In one embodiment of the present invention, the primary extraction kettle (5) is connected to the gas compression pump (1) through a pipeline, and a gas stop valve I (39) and a compressed gas three-way valve (37) are provided on the pipeline between the primary extraction kettle (5) and the gas compression pump (1);

[0009] In one embodiment of the present invention, a feed pump I (2), a raw material valve I (28) and a three-way valve III (38) are provided on the pipeline between the raw material tank I (12) and the primary extraction kettle (5);

[0010] In one embodiment of the present invention, a gas valve I (32) is provided on the pipeline between the primary extraction kettle (5) and the condenser I (15);

[0011] In one embodiment of the present invention, a control valve I (21) is provided on the pipeline between the condenser I (15) and the alkane buffer tank (17);

[0012] In one embodiment of the present invention, a circulation pump (8) is provided on the pipeline between the alkane buffer tank (17) and the alkane storage tank (10);

[0013] In one embodiment of the present invention, the bottom of the alkane storage tank (10) is connected to the three-way valve III (38), the top of the alkane storage tank (10) is provided with a vent valve I (19), and the side wall of the alkane storage tank (10) is provided with a light distillate oil-II production port.

[0014] In one embodiment of the present invention, a discharge valve II (27) is provided at the bottom of the secondary extraction kettle (6), an electric auxiliary heating device and an ultrasonic radiation device are provided on the outer wall of the secondary extraction kettle (6), the electric auxiliary heating device and the ultrasonic radiation device are respectively connected to the magnetic thermal controller II (4), a motor II (43), a pressure gauge II (25) and a vent valve IV (35) are provided on the top of the secondary extraction kettle (6), and a stirrer II (24) is provided in the middle of the secondary extraction kettle (6), and the stirrer II (24) is connected to the motor II (43).

[0015] In one embodiment of the present invention, a discharge valve I (26) is provided on the pipeline between the secondary extraction kettle (6) and the primary extraction kettle (5);

[0016] In one embodiment of the present invention, the secondary extraction kettle (6) is connected to the compressed gas three-way valve (37) through a pipeline, and a gas stop valve II (45) is provided on the pipeline between the secondary extraction kettle (6) and the compressed gas three-way valve (37);

[0017] In one embodiment of the present invention, a gas valve II (33) is provided on the pipeline between the secondary extraction kettle (6) and the condenser II (16);

[0018] In one embodiment of the present invention, a control valve III (44) is provided on the pipeline between the condenser II (16) and the phase separation tank (18);

[0019] In one embodiment of the present invention, a control valve II (29) and a circulation pump II (9) are provided on the pipeline between the phase separation tank (18) and the graded solvent storage tank (11);

[0020] In one embodiment of the present invention, a three-way valve II (31) is provided on the pipeline between the graded solvent storage tank (11) and the secondary extraction kettle (6);

[0021] In one embodiment of the present invention, a vent valve II (20) is provided on the top of the graded solvent storage tank (11), the inlet of the graded solvent storage tank (11) is connected to the circulation pump II (9), and the outlet of the graded solvent storage tank (11) is connected to the three-way valve II (31);

[0022] In one embodiment of the present invention, the raw material tank II (13) and the three-way valve II (31) are connected via a pipeline, a feed pump II (7) is provided on the pipeline between the raw material tank II (13) and the three-way valve II (31), and a raw material valve II (40) is provided on the pipeline between the raw material tank II (13) and the feed pump II (7);

[0023] In one embodiment of the present invention, the raw material tank III (14) is connected to the feed pump II (7) through a pipeline, and a raw material valve III (41) is provided on the pipeline between the raw material tank III (14) and the feed pump II (7);

[0024] In one embodiment of the present invention, the raw material tank II (13) and the raw material tank III (14) are both connected to the three-way valve I (30) through a pipeline, and the three-way valve I (30) is also connected to the feeding device through a pipeline. A control valve IV (46) is provided on the pipeline between the three-way valve I (30) and the feeding device.

[0025] In a second aspect, the present invention provides a process for enriching aromatics in a medium- and low-temperature coal tar mesophase, comprising the following steps:

[0026] a. placing the medium-low temperature coal tar intermediate phase in a primary extraction kettle (5) through a conveying system, extracting the medium-low temperature coal tar intermediate phase with a first graded extractant to remove light distillate oil-II from its organic components to obtain enriched crude aromatics;

[0027] b: The second graded extractant is conveyed to the secondary extraction kettle (6) to extract the mixture to obtain enriched refined aromatics.

[0028] In one embodiment of the present invention, step a includes the following process:

[0029] a1) Replace the residual air in the system with N2 atmosphere by the gas compression pump (1), open the feed liquid valve I (36), meter the medium and low temperature coal tar intermediate phase and inject it into the first extraction kettle (5), open the stirring device, adjust the vent valve III (34) according to the pressure gauge I (22), open the raw material valve I (28), the feed pump I (2) and the three-way valve III (38), add the first graded extractant in the raw material tank I (12) into the first extraction kettle (5), close the feed pump I (2), open the gas compression pump (1), the compressed gas three-way valve (37) and the gas stop valve I (39) to ensure that the gas path is connected and filled with N2, then close the corresponding valve of the stamping system, open the magnetic thermal controller I (3), heat the first extraction kettle (5) to 30-45 ° C, and start the ultrasonic radiation device to extract for 0.3-0.5h;

[0030] a2) Turn off the motor I (42) and the ultrasonic radiation device, open the gas valve I (32), turn on the thermal control system to heat the primary extraction kettle (5) to 90-105°C and maintain it for a certain period of time, turn on the condenser I (15), and transport the coolant to the alkane buffer tank (17) through the control valve I (21). The circulating pump II (8) transports the liquid in the alkane buffer tank (17) to the alkane storage tank (10) for storage. The solvent in the alkane storage tank (10) and the first graded extractant in the raw material tank I (12) enter the primary extraction kettle (5) again for secondary extraction;

[0031] a3) Repeat the extraction steps several times, open the discharge valve I (26), close the gas stop valve I (39) and the gas valve I (32), and transfer the enriched crude aromatics to the secondary extraction kettle (6).

[0032] In one embodiment of the present invention, step b includes the following process:

[0033] b1) Open the raw material valve II (40), raw material valve III (41), feed pump II (7) and three-way valve II (31) to ensure that the conveying pipeline is unobstructed, and the second graded extractant in the raw material tank II (13) and the raw material tank III (14) enters the secondary extraction kettle (6) in proportion, and open the compressed gas three-way valve (37), gas compression pump (1), and gas stop valve II (45) in sequence to ensure that the gas path is connected. According to the pressure gauge II (25), the N2 pressure in the secondary extraction kettle (6) is adjusted to 0.1-0.3MPa, and then the gas compression pump (1) is closed. The magnetic thermal controller II (4) is turned on to heat the secondary extraction kettle (6) to 40-55°C, and ultrasonic radiation is turned on to extract for 0.4-0.6h;

[0034] b2) turning off the ultrasonic radiation device of the motor II (43) and the magnetic thermal controller II (4), opening the gas valve II (33), and raising the temperature of the secondary extraction kettle (6) to 80-100°C;

[0035] b3) opening the gas valve II (33) and the condenser II (16), the condensate enters the phase separation tank (18) after the control valve III (44), and then separates the second graded extractant and the mesophase phenol oil through phase separation, and then opens the control valve II (29) and the circulation pump II (9) in sequence, and conveys the second graded extractant to the graded solvent storage tank (11). The graded solvent storage tank (11) is provided with a vent valve II (20), and the second graded extractant in the tank is circulated to the secondary extraction kettle (6) after the three-way valve II (31);

[0036] b4) Repeat the extraction steps several times, open the discharge valve II (27), close the gas stop valve II (45) and the gas valve II (33), and collect the product enriched in refined aromatics.

[0037] In one embodiment of the present invention, the process for enriching aromatics in the mesophase of medium- and low-temperature coal tar further comprises the following steps: c. recovery and re-gradation of the extraction solvent; step c comprises the following process:

[0038] c1) After step a1 is completed, the vent valve III (34) is opened to discharge N2 to normal pressure and the volatile gas is collected for recycling. The circulating solvent enters the circulation through the alkane storage tank (10) and the three-way valve III (38). The mass of the extraction solution is 95% of the previous extraction solvent;

[0039] c2) After step b2 is completed, the phase separation tank (18) is cooled to -10°C to separate the second graded extractant and the light phenol oil, and the control valve IV (46) and the three-way valve I (30) are opened. The fresh extract is calculated and distributed into the raw material tank II (13) and the raw material tank III (14) through the control valve three-way valve I (30) to ensure the extraction ratio of the second graded extractant and the enriched crude aromatics.

[0040] In one embodiment of the present invention, in step a and step b, the number of extraction cycles is ≥3;

[0041] In one embodiment of the present invention, in step a, the first graded extractant is composed of petroleum ether with a boiling range of 30-60° C. and petroleum ether with a boiling range of 60-90° C. in a mass ratio of (0.8-1.2):1;

[0042] In one embodiment of the present invention, in step b, the second graded extractant is composed of methanol and ethanol in a mass ratio of (1.8-2.2):1.

[0043] In summary, the present invention provides an apparatus and process for enriching aromatics in the mesophase of medium- and low-temperature coal tar. The beneficial effects of the present invention are:

[0044] The boiling points of the graded extractants used in the present invention are all lower than 90°C, and the operation is carried out under mild conditions. The recycling and utilization efficiency of the extraction solvent is high and the energy consumption is low. The present invention adopts inert gas N2 as the system protection gas to avoid the occurrence of explosive scenarios caused by the enrichment of volatile gases. The present invention designs a new low-boiling point graded solvent to separate and enrich aromatic hydrocarbons, selects chain alkanes to selectively destroy the entanglement between molecules in the medium and low temperature coal tar intermediate phase, and selects chain alkanol graded solvents to destroy the strong hydrogen bonding and strong hydrogen bonding / π-π composite effects in the enriched crude aromatic hydrocarbons. Compared with traditional high-boiling point extractants such as N-methylpyrrolidone and N,N-dimethylformamide, the toxicity is weak, the price is low and it is easy to recycle, which effectively reduces energy consumption and is a green process technology.

[0045] Furthermore, the present invention starts from the organic components of the mesophase of medium- and low-temperature coal tar, and separates in step a a light fraction oil-II mainly composed of paraffins. This fraction is mixed with the light fraction oil-I obtained by distillation and can be sold as light oil. The light phenol oil and enriched refined aromatics separated in step b are high-value-added fine chemicals. From the perspective of graded utilization, different high-value fine chemicals such as alkoxyphenols, naphthalene, alkylnaphthalene, anthracene, pyrene, and benzo[ghi]perylene can be obtained through pressurized gradient column chromatography and step-by-step recrystallization.

[0046] Furthermore, the process of the present invention is reasonable, the flow is simple, the operating conditions are mild, and it has the characteristics of short production cycle and flexible operation. According to the differences between the molecular properties of organic group components, different organic components are gently and directionally separated to obtain high-value fine chemical matrices. It is a green and efficient method for separating and producing fine chemicals. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A schematic structural diagram of an aromatics enrichment device for medium- and low-temperature coal tar mesophase provided in one embodiment of the present invention.

[0048] Figure 2 A flow chart of a process for enriching aromatics in the mesophase of medium- and low-temperature coal tar is provided as an embodiment of the present invention.

[0049] Description of main element symbols:

[0050] Among them, 1. gas compression pump; 2. feed pump I; 3. magnetocaloric controller I; 4. magnetocaloric controller II; 5. primary extraction kettle; 6. secondary extraction kettle; 7. feed pump II; 8. circulation pump I; 9. circulation pump II; 10. alkane storage tank; 11. graded solvent storage tank; 12. raw material tank I; 13. raw material tank II; 14. raw material tank III; 15. condenser I; 16. condenser II; 17. alkane buffer tank; 18. phase separation tank; 19. vent valve I; 20. vent valve II; 21. control valve I; 22. pressure gauge I; 23. agitator I; 24. agitator II; 25. Pressure gauge II; 26. Discharge valve I; 27. Discharge valve II; 28. Raw material valve I; 29. ​​Control valve II; 30. Three-way valve I; 31. Three-way valve II; 32. Gas valve I; 33. Gas valve II; 34. Vent valve III; 35. Vent valve IV; 36. Liquid valve I; 37. Compressed gas three-way valve; 38. Three-way valve III; 39. Gas stop valve I; 40. Raw material valve II; 41. Raw material valve III; 42. Motor I; 43. Motor II; 44. Control valve III; 45. Gas stop valve II; 46. Control valve IV. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention for which protection is sought, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0052] Example 1

[0053] Please refer to Figure 1 The embodiment discloses an aromatics enrichment device for the mesophase of medium- and low-temperature coal tar, which mainly comprises a primary extraction kettle 5, a secondary extraction kettle 6, a condenser I15, a condenser II 16, a raw material tank I12, a raw material tank II 13, a raw material tank III 14, an alkane storage tank 10, a graded solvent storage tank 11, an alkane buffer tank 17, a phase separation tank 18, and corresponding pressure pipeline systems, a magnetothermal control system, an extract delivery and recovery system, a valve control system, and a pipeline system.

[0054] The outlet of the raw material tank I12 is connected to the inlet of the first-stage extraction kettle 5 through a pipeline, the first outlet of the first-stage extraction kettle 5 is connected to the inlet of the second-stage extraction kettle 6 through a pipeline, the outlet of the first-stage extraction kettle 5 is connected to the inlet of the condenser I15 through a pipeline, the condenser I15 cools the first graded extractant and the light distillate oil-II gas, the outlet of the condenser I15 is connected to the inlet of the alkane buffer tank 17 through a pipeline, the alkane buffer tank 17 is used to collect condensate, the outlet of the alkane buffer tank 17 is connected to the inlet of the alkane storage tank 10 through a pipeline, and the outlet of the alkane storage tank 10 is connected to the inlet of the first-stage extraction kettle 5 through a pipeline.

[0055] The outlets of the raw material tank II 13 and the raw material tank III 14 are both connected to the inlet of the secondary extraction kettle 6 via a pipeline, the outlet of the secondary extraction kettle 6 is connected to the inlet of the condenser II 16 via a pipeline, the outlet of the condenser II 16 is connected to the inlet of the phase separation tank 18 via a pipeline, the outlet of the phase separation tank 18 is connected to the inlet of the graded solvent storage tank 11 via a pipeline, and the outlet of the graded solvent storage tank 11 is connected to the inlet of the secondary extraction kettle 6 via a pipeline.

[0056] A discharge valve 126 is provided at the bottom of the first-stage extraction kettle 5. An electric auxiliary heating device and an ultrasonic radiator are installed on the outer wall of the first-stage extraction kettle 5. The electric auxiliary heating device and the ultrasonic radiator are respectively connected to a magnetic thermal controller 13. A motor 142 is installed at the top of the first-stage extraction kettle 5. A stirrer 123 is provided in the middle of the first-stage extraction kettle 5, and the stirrer 123 is connected to the motor 142. A pressure gauge 122 and a vent valve 34 are installed at the top of the first-stage extraction kettle 5. The pressure gauge 122 detects the pressure within the kettle, and the vent valve 34 regulates the pressure within the kettle.

[0057] The first-stage extraction kettle 5 is connected to the feeding device through a pipeline, and a liquid valve I 36 is provided on the pipeline between the first-stage extraction kettle 5 and the feeding device; the first-stage extraction kettle 5 is connected to the gas compression pump 1 through an N2 inlet pipeline, and a gas stop valve I 39 and a compressed gas three-way valve 37 are provided on the N2 inlet pipeline between the first-stage extraction kettle 5 and the gas compression pump 1; a feed pump I 2, a raw material valve I 28 and a three-way valve III 38 are provided on the pipeline between the raw material tank I12 and the first-stage extraction kettle 5; a gas valve I 32 is provided on the pipeline between the first-stage extraction kettle 5 and the condenser I15; a control valve I 21 is provided on the pipeline between the condenser I15 and the alkane buffer tank 17; and a circulation pump I 8 is provided on the pipeline between the alkane buffer tank 17 and the alkane storage tank 10.

[0058] The bottom of the alkane storage tank 10 is connected to the three-way valve III 38, the top of the alkane storage tank 10 is provided with a vent valve I19, and the side wall of the alkane storage tank 10 is provided with a light distillate oil-II production outlet.

[0059] A discharge valve II 27 is provided at the bottom of the secondary extraction kettle 6. An electric auxiliary heating device and an ultrasonic radiator are provided on the outer wall of the secondary extraction kettle 6. The electric auxiliary heating device and the ultrasonic radiator are respectively connected to the magnetic thermal controller II 4. A motor II 43 is provided on the top of the secondary extraction kettle 6. An agitator II 24 is provided in the middle of the secondary extraction kettle 6. The agitator II 24 is connected to the motor II 43. A pressure gauge II 25 and a vent valve IV 35 are provided on the top of the secondary extraction kettle 6. The pressure gauge is used to detect the pressure in the kettle, and the vent valve IV 35 is used to regulate the pressure in the kettle.

[0060] A discharge valve I 26 is provided on the pipeline between the secondary extraction kettle 6 and the primary extraction kettle 5; the secondary extraction kettle 6 is connected to a compressed gas three-way valve 37 via a pipeline, and a gas stop valve II 45 is provided on the pipeline between the secondary extraction kettle 6 and the compressed gas three-way valve 37; a gas valve II 33 is provided on the pipeline between the secondary extraction kettle 6 and the condenser II 16, the condenser II 16 cools the second graded extractant and the mesophase phenol oil gas, and a control valve III 44 is provided on the pipeline between the condenser II 16 and the phase separation tank 18; a control valve II 29 and a circulation pump II9 are provided on the pipeline between the phase separation tank 18 and the graded solvent storage tank 11; a three-way valve II 31 is provided on the pipeline between the graded solvent storage tank 11 and the secondary extraction kettle 6; a vent valve II 20 is provided on the top of the graded solvent storage tank 11, the inlet of the graded solvent storage tank 11 is connected to the circulation pump II 9, and the outlet of the graded solvent storage tank 11 is connected to the three-way valve II 31.

[0061] The raw material tank II 13 is connected to the three-way valve II 31 via a pipeline, a feed pump II 7 is provided on the pipeline between the raw material tank II 13 and the three-way valve II 31, and a raw material valve II 40 is provided on the pipeline between the raw material tank II 13 and the feed pump II 7; the raw material tank III 14 is connected to the feed pump II 7 via a pipeline, and a raw material valve III 41 is provided on the pipeline between the raw material tank III 14 and the feed pump II 7; the raw material tank II 13 and the raw material tank III 14 are both connected to the three-way valve I 30 via pipelines, and the three-way valve I 30 is also connected to the feeding device via a pipeline, and a control valve IV 46 is provided on the pipeline between the three-way valve I 30 and the feeding device.

[0062] Example 2

[0063] A process for enriching aromatics in a medium- and low-temperature coal tar mesophase comprises the following steps:

[0064] Step a: A medium-low temperature coal tar mesophase is placed in a primary extraction kettle 5 via a conveying system. A first graded extractant prepared with a low-boiling point paraffin is used to extract the medium-low temperature coal tar mesophase to remove light distillate oil-II from its organic components, thereby obtaining enriched crude aromatics. The light distillate oil-II is mixed with the light distillate oil-I obtained by distillation and can be sold as light oil. In the embodiment, the first graded extractant is composed of petroleum ether with a boiling range of 30-60°C and petroleum ether with a boiling range of 60-90°C. The mass ratio of the petroleum ether with a boiling range of 30-60°C to the petroleum ether with a boiling range of 60-90°C is selected from 1:3, 1:2, 1:1, 2:1, or 3:1.

[0065] Step b: The second graded extractant is conveyed through the system to the secondary extraction kettle 6 to extract the mixture to obtain enriched refined aromatics. In the embodiment, the second graded extractant is composed of methanol and ethanol, and the mass ratio of methanol to ethanol is selected from 1:3, 1:2, 1:1, 2:1, and 3:1.

[0066] Step c: The solvent recovery system realizes the recovery and re-gradation of the extraction solvent to ensure the extraction efficiency of steps a and b.

[0067] Step a includes the following process:

[0068] a1. First, turn on the gas compression pump 1 to replace the residual air in the equipment with N2 to ensure that the equipment maintains an inert environment. Next, open the feed-liquid valve I 36 and meter the medium-low temperature coal tar mesophase preheated to a certain temperature into the primary extraction kettle 5. During the transportation process, turn on the motor 1 42 to drive the stirrer I 23 to ensure that the feed liquid is evenly distributed. During this process, the open and closed state of the vent valve III 34 is determined based on the parameters displayed on the pressure gauge I 22.

[0069] a2. Open the raw material valve I 28, turn on the feed pump I 2, and adjust the flow direction of the three-way valve III 38 to ensure that the first graded extractant in the raw material tank I12 enters the first-stage extraction kettle 5;

[0070] a3. Turn off the feed pump 12, turn on the gas compression pump 1, adjust the connection direction of the compressed gas three-way valve 37 and open the gas stop valve 1 39. After filling the nitrogen to 0.3 MPa, close the gas compression pump 1 and the corresponding valves of the stamping system;

[0071] a4. Turn on the magnetic thermal controller I 3 to ensure that the temperature in the first-stage extraction kettle 5 is maintained at 30-45°C, turn on the ultrasonic radiation magnetic stirring to perform extraction, and extract under the above conditions for 0.3h;

[0072] a5. After the extraction is completed, the motor I 42 is turned off, the ultrasonic radiation device is turned off, the gas valve I 32 is opened, and the thermal control system is turned on to raise the temperature to 95° C. to recover the extraction solvent and separate the light distillate oil-II from the medium- and low-temperature coal tar mesophase system;

[0073] a6. In the solvent recovery and light distillate oil-II production system, the liquid cooled by the condenser I15 enters the alkane buffer tank 17 through the control valve I21. The circulating pump I8 transports the liquid in the alkane buffer tank 17 to the alkane storage tank 10 for storage. The vent valve I19 is used to regulate the pressure in the tank.

[0074] a7, the solvent in the alkane storage tank 10 and the first graded extractant in the raw material tank I12 are mixed in proportion and then enter the first-level extraction kettle 5 for secondary extraction;

[0075] A8, repeat the above-mentioned extraction step, i.e., steps a2, a3, a4, a5 and a6 more than twice, in particular, in step a3, through gas compression pump 1, fill N2 to primary extraction kettle 5, the first extraction pressure is maintained at 0.3MPa, and the pressure of each circulation extraction is improved by 0.1MPa on the basis of the first time; in step a4, the first extraction time is 0.3h, and the circulation extraction time is improved by 0.1h on the basis of the first time. After the two phases are clearly separated, by means of the pressure in the kettle, open the discharge valve 1 26, close the gas end valve 1 39 and the gas valve 1 32, and the enriched crude aromatics are transferred to the secondary extraction kettle 6.

[0076] Step b includes the following process:

[0077] b1. Open the raw material valve II 40 and the raw material valve III 41, turn on the feed pump II 7, and adjust the flow direction of the three-way valve II 31 so that the raw material tank II 13 is filled with methanol and the raw material tank III 14 is filled with ethanol. Then ensure that the solvents in the raw material tanks II 13 and III 14 enter the secondary extraction kettle 6 according to the preparation ratio.

[0078] b2. Adjust the connection direction of the compressed gas three-way valve 37, open the gas compression pump 1 and the gas stop valve II 45 in sequence, observe the changes in the pressure gauge II 25, fill the secondary extraction kettle 6 with nitrogen to 0.1 MPa, and then close the gas compression pump 1;

[0079] b3. Turn on the magnetic thermal controller II 4 to ensure that the temperature in the secondary extraction kettle 6 is maintained at 50° C., turn on the ultrasonic radiation magnetic stirring to carry out extraction, and extract under the above conditions for 0.4 h;

[0080] b4. After the extraction is completed, turn off the motor II 43, turn off the ultrasonic radiation device, open the gas valve II 33, turn on the thermal control system to raise the temperature to 90° C., and recover the extraction solvent and separate the mesophase phenol oil from the enriched crude aromatics system;

[0081] b5, the extract and the mesophase phenol oil enter the condenser II 16 through the gas valve II 33, and the condensate enters the phase separation tank 18 after passing through the control valve III44. After the extract and the mesophase phenol oil are separated by phase separation, the control valve II 29 and the circulating pump II9 are opened in sequence, and the separated extract is transported to the graded solvent storage tank 11. The graded solvent storage tank 11 is provided with a vent valve II 20 to control the pressure in the tank;

[0082] b6. The extract in the graded solvent storage tank 11 is circulated to the secondary extraction kettle 6 after passing through the three-way valve II 31, and the component ratio of the graded solvent is controlled by the calculation of the three-way valve I 31;

[0083] B7, repeat the above-mentioned extraction step, i.e. steps b1, b2, b3, b4 and b5 more than twice, in particular, in step b2, through gas compression pump 1, fill N2 to secondary extraction kettle 6, the first extraction pressure is maintained at 0.1MPa, and the pressure of circulation extraction is improved by 0.1MPa on the basis of the first time; In step b3, the first extraction time is 0.4h, and the circulation extraction time is improved by 0.1h on the basis of the first time. After the two phases are clearly layered, by means of the pressure in the kettle, open discharge valve II 27, close gas end valve II 45 and gas valve II 33, collect product enrichment refined aromatics;

[0084] b8. According to the change of the liquid level of the raw material tank III 14, the control valve IV 46 is opened or closed to ensure that the liquid level remains stable.

[0085] Step c includes the following process:

[0086] c1: In step a, after step a4 is completed, the vent valve III 34 is opened to release N2 to normal pressure and collect the volatile gas for recycling, thereby reducing the distillation temperature for separation and recovery of the extraction solvent and light distillate oil-II;

[0087] c2: In the solvent recovery and light distillate oil-II production system in step a, to ensure the recycling extraction efficiency, the recycled solvent enters the recycling extraction solution through the alkane storage tank 10 and the three-way valve III 38, and the quality is 95% of the previous extraction solvent;

[0088] c3: in step b, after step b4 is completed, open the vent valve II 33, release the N2 to normal pressure and collect the volatile gas for recycling, thereby reducing the distillation temperature for separation and recovery of the graded solvent and the mesophase phenol oil;

[0089] c4: In step b, the phase separation tank 18 is provided with a cooling device, and the temperature is reduced to -10°C to achieve rapid separation of the second graded extractant and the light phenol oil;

[0090] c5: Fresh extract from outside the boundary is connected to the three-way valve I 30 through the control valve IV 46, and enters the raw material tank II 13 and the raw material tank III 14 after calculation and distribution by the control valve three-way valve I 30 to ensure the extraction ratio of the second graded extractant and the enriched crude aromatics.

[0091] Test results:

[0092] Light distillate oil-II, mesophase phenol oil and enriched aromatic components are shown in Appendix 1.

[0093] Table 1 Gas chromatography / mass spectrometry analysis results of light distillate oil-II, mesophase phenol oil and enriched refined aromatics in Example

[0094]

[0095] Note: 30-60℃ petroleum ether: 60-90℃ petroleum ether is expressed as A:B; methanol: ethanol is expressed as C:D.

[0096] In summary, the present invention can obtain a medium-low temperature coal tar mesophase by fractionating medium-low temperature coal tar, which not only solves the problem of difficult separation of solid inorganic matter in the components, but also achieves the initial enrichment of aromatic hydrocarbons, providing a reliable foundation for the efficient enrichment of aromatic hydrocarbons in the medium-low temperature coal tar mesophase. Furthermore, the external field cavitation force of extraction / retraction, stirring and ultrasonic synergistic interaction is adopted to selectively utilize or destroy the interaction between organic matter groups in the medium-low temperature coal tar mesophase, that is, selectively destroy the alkyl-alkyl entanglement between organic molecular groups, the π-π interaction between aromatic rings, weak hydrogen bonding, strong hydrogen bonding and strong hydrogen bonding / π-π complex interaction between aromatic rings, and learn from the correlation between islands and archipelagos in petroleum genomics to achieve rapid enrichment of aromatic ring-rich organic groups. Organic groups rich in aromatic rings can be further separated by pressurized gradient column chromatography and step-by-step recrystallization to obtain high-value fine chemicals such as naphthalene, alkylnaphthalene, anthracene, pyrene, and benzo[ghi]perylene. The heavy soluble phase does not contain any small particles and can be used to prepare foamed carbon, carbon microspheres, asphalt carbon fibers, and anti-setting road asphalt.

[0097] The present invention starts from the organic components of the mesophase of medium- and low-temperature coal tar. In step a, a light fraction oil-II mainly composed of paraffins is separated and obtained. This fraction is mixed with the light fraction oil-I obtained by distillation and can be sold as light oil. The light phenol oil and enriched refined aromatics separated in step b are high-value-added fine chemicals. From the perspective of graded utilization, different high-value fine chemicals such as alkoxyphenols, naphthalene, alkylnaphthalene, anthracene, pyrene, and benzo[ghi]perylene can be obtained through pressurized gradient column chromatography and step-by-step recrystallization.

[0098] The above is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. Medium and low temperature coal tar mesophase aromatics enrichment equipment, characterized by: It includes a raw material tank I (12), a primary extraction kettle (5), an alkane storage tank (10), a condenser I (15), an alkane buffer tank (17), a secondary extraction kettle (6), a raw material tank II (13), a raw material tank III (14), a condenser II (16), a graded solvent storage tank (11) and a phase separation tank (18); The outlet of the raw material tank I (12) is connected to the inlet of the first-stage extraction kettle (5) through a pipeline, the first outlet of the first-stage extraction kettle (5) is connected to the inlet of the second-stage extraction kettle (6) through a pipeline, the outlet of the first-stage extraction kettle (5) is connected to the inlet of the condenser I (15) through a pipeline, the outlet of the condenser I (15) is connected to the inlet of the alkane buffer tank (17) through a pipeline, the outlet of the alkane buffer tank (17) is connected to the inlet of the alkane storage tank (10) through a pipeline, and the outlet of the alkane storage tank (10) is connected to the inlet of the first-stage extraction kettle (5) through a pipeline; The outlets of the raw material tank II (13) and the raw material tank III (14) are connected to the inlet of the secondary extraction kettle (6) through a pipeline, the outlet of the secondary extraction kettle (6) is connected to the inlet of the condenser II (16) through a pipeline, the outlet of the condenser II (16) is connected to the inlet of the phase separation tank (18) through a pipeline, the outlet of the phase separation tank (18) is connected to the inlet of the graded solvent storage tank (11) through a pipeline, and the outlet of the graded solvent storage tank (11) is connected to the inlet of the secondary extraction kettle (6) through a pipeline.

2. The medium-low temperature coal tar mesophase aromatics enrichment equipment according to claim 1, characterized in that: A discharge valve I (26) is provided at the bottom of the first-stage extraction kettle (5), an electric auxiliary heating device and an ultrasonic radiation device are provided on the outer wall of the first-stage extraction kettle (5), and the electric auxiliary heating device and the ultrasonic radiation device are respectively connected to the magnetic heat controller I (3). A motor I (42), a pressure gauge I (22) and a vent valve III (34) are provided on the top of the first-stage extraction kettle (5), and a stirrer I (23) is provided in the middle of the first-stage extraction kettle (5), and the stirrer I (23) is connected to the motor I (42).

3. The medium and low temperature coal tar mesophase aromatics enrichment equipment according to claim 1, characterized in that: It includes any one or more of the following technical features: 1) The first-stage extraction kettle (5) is connected to the feeding device through a pipeline, and a liquid valve I (36) is provided on the pipeline between the first-stage extraction kettle (5) and the feeding device; 2) The first-stage extraction kettle (5) is connected to the gas compression pump (1) through a pipeline. A gas stop valve I (39) and a compressed gas three-way valve (37) are provided on the pipeline between the first-stage extraction kettle (5) and the gas compression pump (1); 3) A feed pump I (2), a raw material valve I (28) and a three-way valve III (38) are provided on the pipeline between the raw material tank I (12) and the first-stage extraction kettle (5); 4) A gas valve I (32) is provided on the pipeline between the primary extraction kettle (5) and the condenser I (15); 5) A control valve I (21) is provided on the pipeline between the condenser I (15) and the alkane buffer tank (17); 6) A circulation pump I (8) is provided on the pipeline between the alkane buffer tank (17) and the alkane storage tank (10); 7) The bottom of the alkane storage tank (10) is connected to the three-way valve III (38), the top of the alkane storage tank (10) is provided with a vent valve I (19), and the side wall of the alkane storage tank (10) is provided with a light distillate oil-II production port.

4. The medium and low temperature coal tar mesophase aromatics enrichment equipment according to claim 1, characterized in that: A discharge valve II (27) is provided at the bottom of the secondary extraction kettle (6), an electric auxiliary heating device and an ultrasonic radiation device are provided on the outer wall of the secondary extraction kettle (6), the electric auxiliary heating device and the ultrasonic radiation device are respectively connected to the magnetic heat controller II (4), a motor II (43), a pressure gauge II (25) and a vent valve IV (35) are provided on the top of the secondary extraction kettle (6), and a stirrer II (24) is provided in the middle of the secondary extraction kettle (6), and the stirrer II (24) is connected to the motor II (43).

5. The equipment for enriching aromatics from the medium and low temperature coal tar mesophase according to claim 3, characterized in that: It includes any one or more of the following technical features: 1) A discharge valve I (26) is provided on the pipeline between the secondary extraction kettle (6) and the primary extraction kettle (5); 2) The secondary extraction kettle (6) is connected to the compressed gas three-way valve (37) through a pipeline, and a gas stop valve II (45) is provided on the pipeline between the secondary extraction kettle (6) and the compressed gas three-way valve (37); 3) A gas valve II (33) is provided on the pipeline between the secondary extraction kettle (6) and the condenser II (16); 4) A control valve III (44) is provided on the pipeline between the condenser II (16) and the phase separation tank (18); 5) A control valve II (29) and a circulation pump II (9) are provided on the pipeline between the phase separation tank (18) and the graded solvent storage tank (11); 6) A three-way valve II (31) is provided on the pipeline between the graded solvent storage tank (11) and the secondary extraction kettle (6); 7) A vent valve II (20) is provided on the top of the graded solvent storage tank (11), the inlet of the graded solvent storage tank (11) is connected to the circulation pump II (9), and the outlet of the graded solvent storage tank (11) is connected to the three-way valve II (31); 8) The raw material tank II (13) is connected to the three-way valve II (31) through a pipeline, a feed pump II (7) is provided on the pipeline between the raw material tank II (13) and the three-way valve II (31), and a raw material valve II (40) is provided on the pipeline between the raw material tank II (13) and the feed pump II (7); 9) The raw material tank III (14) is connected to the feed pump II (7) through a pipeline, and a raw material valve III (41) is provided on the pipeline between the raw material tank III (14) and the feed pump II (7); 10) Both the raw material tank II (13) and the raw material tank III (14) are connected to the three-way valve I (30) through a pipeline. The three-way valve I (30) is also connected to the feeding device through a pipeline. A control valve IV (46) is provided on the pipeline between the three-way valve I (30) and the feeding device.

6. A process for enriching aromatics from a medium- and low-temperature coal tar mesophase, using the apparatus described in any one of claims 1 to 5, characterized in that: It includes the following steps: a: placing the medium-low temperature coal tar intermediate phase into a first-stage extraction kettle (5) through a conveying system, extracting the medium-low temperature coal tar intermediate phase with a first-graded extractant to remove light distillate oil-II from its organic components, thereby obtaining enriched crude aromatics; include The following process: a1) Replace the residual air in the system with N2 atmosphere through the gas compression pump (1), open the feed liquid valve I (36), and inject the medium and low temperature coal tar intermediate phase into the first extraction kettle (5), open the stirring device, adjust the vent valve III (34) according to the pressure gauge I (22), open the raw material valve I (28), the feed pump I (2) and the three-way valve III (38), add the first graded extractant in the raw material tank I (12) into the first extraction kettle (5), close the feed pump I (2), open the gas compression pump (1), the compressed gas three-way valve (37) and the gas stop valve I (39) to ensure that the gas path is connected and filled with N2, open the magnetic thermal controller I (3), heat the first extraction kettle (5) to 30-45℃, and start the ultrasonic radiation device to extract for 0.3-0.5 h; a2) Turn off the motor I (42) and the ultrasonic radiation device, open the gas valve I (32), turn on the thermal control system to heat the first-stage extraction kettle (5) to 90-105 °C and maintain it for a certain period of time, turn on the condenser I (15), and transport the coolant to the alkane buffer tank (17) through the control valve I (21). The circulating pump I (8) transports the liquid in the alkane buffer tank (17) to the alkane storage tank (10) for storage. The solvent in the alkane storage tank (10) and the first-graded extractant in the raw material tank I (12) enter the first-stage extraction kettle (5) again for secondary extraction; a3) Repeat the extraction steps several times, open the discharge valve I (26), close the gas stop valve I (39) and the gas valve I (32), and transfer the enriched crude aromatics to the secondary extraction kettle (6); b: transporting the second graded extractant to the secondary extraction kettle (6) to extract the mixture to obtain enriched refined aromatics; The following processes are included: b1) Open the raw material valve II (40), raw material valve III (41), feed pump II (7) and three-way valve II (31) to ensure that the conveying pipeline is unobstructed, and the second graded extractant in the raw material tank II (13) and the raw material tank III (14) enters the secondary extraction kettle (6) in proportion. Open the compressed gas three-way valve (37), gas compression pump (1) and gas stop valve II (45) in sequence to ensure that the gas path is connected. Adjust the N2 pressure in the secondary extraction kettle (6) to 0.1-0.3 MPa according to the pressure gauge II (25). Then close the gas compression pump (1), turn on the magnetic thermal controller II (4) to heat the secondary extraction kettle (6) to 40-55 °C, and turn on ultrasonic radiation to extract for 0.4-0.6 h; b2) Turn off the ultrasonic radiation device of the motor II (43) and the magnetic thermal controller II (4), open the gas valve II (33), and heat the secondary extraction kettle (6) to 80-100°C; b3) Open the gas valve II (33) and the condenser II (16), and the condensate enters the phase separation tank (18) after passing through the control valve III (44), and then the second graded extractant and the middle phase phenol oil are separated by phase separation. The control valve II (29) and the circulation pump II (9) are opened in sequence to convey the second graded extractant to the graded solvent storage tank (11). The graded solvent storage tank (11) is provided with a vent valve II (20). The second graded extractant in the tank is circulated to the secondary extraction kettle (6) after passing through the three-way valve II (31); b4) Repeat the extraction steps several times, open the discharge valve II (27), close the gas stop valve II (45) and the gas valve II (33), and collect the product enriched with refined aromatics; c. Recovery and re-gradation of extraction solvent; include The following process: c1) After step a1 is completed, the vent valve III (34) is opened to discharge N2 to normal pressure and the volatile gas is collected for recycling. The circulating solvent enters the circulation through the alkane storage tank (10) and the three-way valve III (38). The quality of the extraction solution is 95% of the previous extraction solvent; c2) After step b2 is completed, the phase separation tank (18) is cooled to -10°C to separate the second graded extractant and the light phenol oil, and the control valve IV (46) and the three-way valve I (30) are opened. The fresh extract is calculated and distributed into the raw material tank II (13) and the raw material tank III (14) through the control valve three-way valve I (30) to ensure the extraction ratio of the second graded extractant and the enriched crude aromatics; In step a and step b, the number of extraction cycles is ≥ 3; In step a, the first graded extractant is composed of petroleum ether with a boiling range of 30-60°C and petroleum ether with a boiling range of 60-90°C in a mass ratio of (0.8-1.2):1; In step b, the second graded extractant is composed of methanol and ethanol in a mass ratio of (1.8-2.2):1.

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