Novel high-temperature coal tar fraction separation process and system

Abstract

The invention relates to a novel high-temperature coal tar fraction separation process and system, and belongs to the technical field of coal tar processing, raw material tar is dehydrated to obtain anhydrous tar, the anhydrous tar is heated to 380 DEG C for reduced pressure distillation, three mixed oil, anthracene oil and maltha are extracted at the same time, the maltha and an organic solvent are mixed and heated to 310-330 DEG C, and the mixture is cooled to the room temperature to obtain the high-temperature coal tar fraction. And then carrying out supercritical extraction to obtain hard asphalt and an extraction mixture, and separating the extraction mixture to obtain an organic solvent and high-performance carbon material raw material asphalt. The high-temperature coal tar fraction separation process disclosed by the invention is simple to operate and stable in operation, and can be used for producing a high-performance carbon material asphalt raw material which contains ultralow QI (Quality Index) and ash content and is uniform and concentrated in molecular weight.

Description

Technical Field

[0001] The invention relates to the technical field of coal tar processing, and in particular to a novel high-temperature coal tar fraction separation process and system using vacuum distillation and supercritical extraction processes. Background Art

[0002] China produces nearly 20 million tons of high-temperature coal tar every year through high-temperature coking, and the resources are very rich. The main components of coal tar are polycyclic aromatic compounds, which are the main source of polycyclic aromatic compounds in current industrial production.

[0003] Coal tar is mainly composed of 2-4 ring components, which are transferred to light fractions such as light oil, phenol oil, naphthalene oil, wash oil, anthracene oil, etc. during the distillation process. Among them, the components with relatively high content include naphthalene, indole, anthracene, carbazole, phenanthrene, fluorene, fluoranthene, benzophenone, pyrene, phenols, aniline, quinoline, pyridine, etc. The above components are important raw materials and intermediates for modern chemical industry and advanced materials manufacturing industry, and are the basic raw materials for fine chemical products such as synthetic plastics, synthetic fibers, pesticides, dyes, medicines, coatings, additives, etc.

[0004] The coal tar industry in developed countries started earlier and has advanced technology, and has achieved full processing and utilization of coal tar components. Relatively speaking, my country's coal tar industry started late. In recent years, the heavy component of coal tar has developed rapidly due to the transformation and development of the steel industry, which has stimulated the demand for carbon materials related to graphite electrode production. However, high-end carbon material raw materials are mainly imported. The defects of traditional processes have led to the fact that the added value of asphalt products, which account for nearly 60% of coal tar components in my country, has not increased.

[0005] In view of the above phenomenon, the inventors have invented a new high-temperature coal tar fraction separation process to improve the utilization rate of coal tar resources and meet the demand for high-end carbon material raw materials. Summary of the invention

[0006] The purpose of the present invention is to provide a new high-temperature coal tar fraction separation process and system to solve the problem of high-end asphalt raw materials, while focusing on improving energy recovery and reducing process energy consumption costs, and increasing the concentration of high value-added light components.

[0007] The present invention provides a novel high-temperature coal tar fraction separation process, which adopts the following technical scheme: A novel high-temperature coal tar fraction separation process is characterized by comprising the following steps: S1, heating the raw tar to 190° C., and then dehydrating it to obtain anhydrous tar; S2, heating the anhydrous tar obtained in step S1 to 380° C., and then performing vacuum distillation, wherein the pressure of the vacuum distillation is maintained at -60 to -80 KPa, and three mixed oils, anthracene oil and soft asphalt are produced during the vacuum distillation; S3. The soft asphalt obtained in step S2 is mixed with an organic solvent and heated to 310-330°C, and then subjected to supercritical extraction to obtain hard asphalt and an extraction mixture. The extraction mixture is separated to obtain an organic solvent and a high-performance carbon material raw material asphalt.

[0008] Preferably, the dehydration treatment in step S1 also includes light oil reflux.

[0009] Preferably, the temperature of the produced three-mixed oil in step S2 is 180-230°C, and the produced three-mixed oil is subjected to heat exchange treatment to control the temperature of the three-mixed oil to be 120-150°C.

[0010] Preferably, the temperature of the anthracene oil produced in step S2 is 260-290°C, and the produced anthracene oil is subjected to heat exchange treatment to control the temperature of the anthracene oil to be 100-130°C.

[0011] Preferably, the organic solvent in step S3 includes toluene and n-hexane.

[0012] Preferably, the naphthalene content in the three-mixed oil in step S2 is 50-60%.

[0013] The invention also provides a novel high-temperature coal tar fraction separation system.

[0014] A novel high-temperature coal tar fraction separation system, comprising: A dehydration tower, wherein a reboiler is connected to a feed end of the dehydration tower; A tubular heating furnace connected to the discharge end of the dehydration tower; A vacuum distillation tower is connected to the discharge end of the tubular heating furnace. A supercritical extraction kettle is connected to the asphalt discharge end of the vacuum distillation tower, a heater is provided between the supercritical extraction kettle and the vacuum distillation tower, and an organic solvent delivery pipe is also provided between the heater and the vacuum distillation tower; The separator is connected to the top discharge end of the supercritical extraction kettle, and the separator is communicated with the organic solvent delivery pipe.

[0015] Preferably, the dehydration tower is a distillation tower provided with seven layers of tower plates, and a light oil reflux pipeline is provided at the top of the dehydration tower.

[0016] Preferably, the vacuum distillation tower has 40 to 50 plates, and the feed end of the vacuum distillation tower is located at the third plate; An anthracene oil extraction end is provided in the middle of the vacuum distillation tower, and the anthracene oil extraction end is connected to a heat transfer oil heat exchanger; A three-mixed oil production end is arranged at the top of the vacuum distillation tower, and the three-mixed oil production end is connected to a heat transfer oil heat exchanger.

[0017] Preferably, a fractionator is provided at the top of the vacuum distillation tower.

[0018] In summary, the present invention includes the following beneficial technical effects: 1. In a novel high-temperature coal tar fraction separation process of the present application, the raw tar is dehydrated to remove water and light oil in the raw tar. During the vacuum distillation process, three mixed oils, anthracene oil and soft asphalt are extracted simultaneously, which not only achieves the effect of energy saving, but also can improve the concentration of light components such as naphthalene. The supercritical fluid extraction technology is used to effectively remove the ultra-large molecules (quinoline insoluble matter QI) and ash in the asphalt, thereby obtaining a high-performance carbon material asphalt raw material with ultra-low QI, ash content and uniform molecular weight concentration. The obtained high-performance carbon material asphalt raw material has a softening point of 40-60°C, QI≤1%, and ash content <0.01%.

[0019] 2. In a new type of high-temperature coal tar fraction separation system in the present application, the raw tar is processed in sequence through a reboiler, a dehydration tower, a tubular heating furnace and a vacuum distillation tower, mixed with an organic solvent and enters a supercritical extraction kettle, and then enters a separator, thereby completing the preparation of high-performance carbon material asphalt raw materials. The system has the characteristics of simple process, easy operation and good separation effect.

[0020] 3. In the present application, a fractionator is provided at the top of the vacuum distillation tower to produce three mixed oils from the top of the vacuum distillation tower, thereby effectively improving the concentration of light components such as naphthalene, producing anthracene oil in the middle of the vacuum distillation tower, and producing soft asphalt at the bottom of the vacuum distillation tower. The three substances can be produced at the same time, simplifying the production process and reducing the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of a novel high-temperature coal tar fraction separation system of the present application.

[0022] Explanation of the reference numerals: 1. Dehydration tower; 11. Reboiler; 12. Circulation pump; 13. Light oil reflux pipeline; 14. Extraction pump; 2. Tubular heating furnace; 3. Vacuum distillation tower; 31. Anthracene oil production end; 32. Three-mixed oil production end; 33. Fractionator; 34. Asphalt production end; 35. Heat transfer oil heat exchanger; 4. Supercritical extraction kettle; 5. Separator; 6. Pressure pump; 7. Heater; 8. Organic solvent delivery pipe; 9. Expansion valve. DETAILED DESCRIPTION

[0023] The following is combined with Figure 1 The present invention is further described in detail with reference to the accompanying drawings and examples.

[0024] Example 1 A novel high-temperature coal tar fraction separation process comprises the following steps: 1) The raw tar is heated to 190°C in a reboiler, and then transported to a dehydration tower for dehydration. A light oil reflux is set at the top of the dehydration tower to control the water content and light oil content of the mist water tar at the bottom of the dehydration tower through reflux, and finally anhydrous tar is obtained; 2) The anhydrous tar obtained in step 1) is passed into a tubular heating furnace to heat the anhydrous tar to 380°C, and then passed into a vacuum distillation tower for vacuum distillation treatment, and the pressure in the vacuum distillation tower is set at -60~-80 Kpa; the top of the vacuum distillation tower produces a three-mixed oil with a production temperature of 180~230°C, and the produced three-mixed oil enters a heat transfer oil heat exchanger for heat exchange treatment, and the temperature of the three-mixed oil is controlled to be 120~150°C, and the naphthalene content in the three-mixed oil is 50~60%; anthracene oil is produced in the middle of the vacuum distillation tower, and the production temperature is 260~290°C. The produced anthracene oil enters a heat transfer oil heat exchanger for heat exchange treatment, and the temperature of the anthracene oil is controlled to be 100~130°C; soft asphalt is produced at the bottom of the vacuum distillation tower; 3) Mix the soft asphalt obtained in step 2) with an organic solvent and heat it to 310-330°C, wherein the organic solvent includes toluene and n-hexane, and then transport it to a supercritical extraction kettle for supercritical extraction treatment to obtain hard asphalt and an extraction mixture. The hard asphalt is discharged, and the extraction mixture is separated in a separator to obtain an organic solvent and a high-performance carbon material raw asphalt.

[0025] The softening point of the high-performance carbon material raw material asphalt obtained was detected to be 40-60°C, QI≤1%, and ash content less than 0.01%.

[0026] Example 2 Reference Figure 1 A novel high-temperature coal tar fraction separation system comprises a dehydration tower 1, a tubular heating furnace 2, a vacuum distillation tower 3, a supercritical extraction kettle 4 and a separator 5 which are connected in sequence.

[0027] Reference Figure 1 The feed end of the dehydration tower 1 is connected to a reboiler 11, and the feed end of the reboiler 11 is connected to a circulating pump 12. The raw tar enters the reboiler 11 through the circulating pump 12, and after being heated to 190°C by the reboiler 11, it enters the dehydration tower 1 from the bottom end. The dehydration tower 1 is a distillation tower with seven trays, and a light oil reflux pipeline 13 is provided at the top of the dehydration tower 1. The water content and light oil content of the mist water tar at the bottom of the dehydration tower 1 are controlled by reflux, and finally anhydrous tar is obtained.

[0028] Reference Figure 1 An extraction pump 14 is provided between the discharge end at the bottom end of the dehydration tower 1 and the feed end of the tubular heating furnace 2, that is, the anhydrous tar is transported to the tubular heating furnace 2 through the extraction pump 14, the tubular heating furnace 2 heats the anhydrous tar to 380°C, and then transports it to the vacuum distillation tower 3.

[0029] Reference Figure 1 The plates of the vacuum distillation tower 3 include 40 to 50 layers, the feed end of the vacuum distillation tower 3 is located at the third plate, an anthracene oil extraction end 31 is arranged in the middle of the vacuum distillation tower 3, and the extraction temperature is 260 to 290°C. The anthracene oil extraction end 31 is connected to a heat transfer oil heat exchanger 35 to maintain the temperature of the anthracene oil at 100 to 130°C; a three-mixed oil extraction end 32 is arranged at the top of the vacuum distillation tower 3, and the extraction temperature is 180 to 230°C. The three-mixed oil extraction end 32 is connected to a heat transfer oil heat exchanger 35 to maintain the temperature of the three-mixed oil at 120 to 150°C, wherein a fractionator 33 is arranged at the top of the vacuum distillation tower 3, and the vacuum distillation tower 3 is refluxed through the fractionator 33; the bottom end of the vacuum distillation device is an asphalt extraction end 34.

[0030] Reference Figure 1 The asphalt extraction end 34 of the vacuum distiller is connected to the extraction pump 14, the pressure pump 6 and the heater 7 in sequence, wherein the pressure pump 6 and the asphalt discharge end of the vacuum distiller are also connected to an organic solvent delivery pipe 8, that is, the organic solvent and soft asphalt delivered by the organic solvent delivery pipe 8 are mixed and delivered to the heater 7 via the pressure pump 6, the heater 7 is heated to 310~330℃, and then delivered to the supercritical extraction kettle 4 to obtain hard asphalt and extraction mixture.

[0031] Reference Figure 1 , the hard asphalt flows out from the bottom of the supercritical extraction kettle 4, and an expansion valve 9 is connected between the top of the supercritical extraction kettle 4 and the separator 5, that is, the extraction mixture is transported from the top of the supercritical extraction kettle 4 to the separator 5 through the expansion valve 9, and the separator 5 separates the organic solvent and the high-performance carbon material raw material asphalt. The separator 5 is connected to the organic solvent delivery pipe 8 to realize the recycling of the organic solvent.

[0032] The above are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A novel high-temperature coal tar fraction separation process, characterized in that: The following steps are involved: S1, heating the raw tar to 190° C., and then dehydrating it to obtain anhydrous tar; S2, heating the anhydrous tar obtained in step S1 to 380° C., and then performing vacuum distillation, wherein the pressure of the vacuum distillation is maintained at -60 to -80 KPa, and three mixed oils, anthracene oil and soft asphalt are produced during the vacuum distillation; S3. The soft asphalt obtained in step S2 is mixed with an organic solvent and heated to 310-330°C, and then subjected to supercritical extraction to obtain hard asphalt and an extraction mixture. The extraction mixture is separated to obtain an organic solvent and a high-performance carbon material raw material asphalt.

2. A novel high-temperature coal tar fraction separation process according to claim 1, characterized in that: The dehydration process in step S1 also includes light oil reflux.

3. A novel high-temperature coal tar fraction separation process according to claim 1, characterized in that: In the step S2, the temperature of the produced three-mixed oil is 180-230°C, and the produced three-mixed oil is subjected to heat exchange treatment to control the temperature of the three-mixed oil to be 120-150°C.

4. A novel high-temperature coal tar fraction separation process according to claim 3, characterized in that: The temperature of the anthracene oil produced in step S2 is 260-290° C., and the produced anthracene oil is subjected to heat exchange treatment to control the temperature of the anthracene oil to be 100-130° C.

5. A novel high-temperature coal tar fraction separation process according to claim 1, characterized in that: The organic solvent in step S3 includes toluene and n-hexane.

6. A novel high-temperature coal tar fraction separation process according to claim 3, characterized in that: The naphthalene content in the three-mixed oil in step S2 is 50-60%.

7. A novel high-temperature coal tar fraction separation system, characterized in that: include, A dehydration tower (1), wherein a feed end of the dehydration tower (1) is connected to a reboiler (11); A tubular heating furnace (2) connected to the discharge end of the dehydration tower (1); The vacuum distillation tower (3) is connected to the discharge end of the tubular heating furnace (2). A supercritical extraction kettle (4) is connected to the asphalt extraction end (34) of the vacuum distillation tower (3); a heater (7) is provided between the supercritical extraction kettle (4) and the vacuum distillation tower (3); and an organic solvent delivery pipe (8) is also provided between the heater (7) and the vacuum distillation tower (3); The separator (5) is connected to the top discharge end of the supercritical extraction kettle (4), and the separator (5) is connected to the organic solvent delivery pipe (8).

8. A novel high-temperature coal tar fraction separation system according to claim 7, characterized in that: The dehydration tower (1) is a distillation tower provided with seven layers of tower trays, and a light oil reflux pipeline (13) is provided at the top of the dehydration tower (1).

9. A novel high-temperature coal tar fraction separation system according to claim 7, characterized in that: The vacuum distillation tower (3) has 40 to 50 tower plates, and the feed end of the vacuum distillation tower (3) is located on the third tower plate; An anthracene oil extraction end (31) is provided in the middle of the vacuum distillation tower (3), and the anthracene oil extraction end (31) is connected to a heat transfer oil heat exchanger (35); A three-mixed oil production end (32) is provided at the top of the vacuum distillation tower (3), and the three-mixed oil production end (32) is connected to a heat transfer oil heat exchanger (35).

10. A novel high-temperature coal tar fraction separation system according to claim 9, characterized in that: A fractionator (33) is provided at the top of the vacuum distillation tower (3).

Images