A coal tar suspension bed coupled with fixed bed hydrocracking process and device

Abstract

The present invention discloses a coal tar suspension bed coupled with a fixed bed hydrocracking process and device, which includes a catalyst storage tank connected to a catalyst mixing tank, and the catalyst mixing tank is connected to a catalyst feed pump; it also includes a coal tar buffer tank, the coal tar buffer tank is connected to a slurry feed pump, the slurry feed pump is connected to a first heating furnace, the first heating furnace is connected to a hydrogen heating furnace, and the hydrogen heating furnace is connected to a first suspension bed reactor; the coal tar buffer tank is also connected to a first vacuum tower, the first vacuum tower is connected to a second heating furnace, the second heating furnace is connected to a hot low-pressure separator, the first suspension bed reactor is connected to a second suspension bed reactor, the outlet of the second suspension bed reactor is connected to a hot high-pressure separator, the hot high-pressure separator is connected to a cyclone separator and a hot medium-pressure separator, and the cyclone separator is connected to a fixed bed reactor. The process flow of the present invention is short, with high conversion rate and light oil yield, low energy consumption, and the reactor and the feed mixing system are not easily blocked, and the vacuum system is not easily worn.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal tar processing, and particularly relates to a coal tar suspension bed coupled fixed bed hydrocracking process and device. Background Art

[0002] Compared with the three residue oil processing methods of fixed bed, fluidized bed, and moving bed, the suspension bed hydrocracking process has a simple process, good adaptability to inferior heavy oils with high sulfur, high viscosity, and high residual carbon, and can also appropriately process a part of pulverized coal; the comprehensive engineering investment is small, the operation flexibility is large, and the start-up time is long; the products have the advantages of high conversion rate, high gasoline-diesel ratio, high demetallization rate, etc., and have broad development prospects in the hydrotreating of inferior heavy oils.

[0003] Currently, existing domestic suspension bed hydrocracking processes must have an independent fixed bed hydrogenation unit downstream or need to perform hydrogenation treatment again during the downstream oil product reprocessing, resulting in high costs and large energy consumption; currently, the imported coal tar suspension bed hydrocracking (VCC) process in China couples the suspension bed and the fixed bed, and the two-stage hydrogenation is in series and the hydrogen passes through once, and the energy consumption is significantly reduced compared with two sets of devices. However, during the operation of this process, first, the adsorbent does not have a catalytic effect, resulting in insufficient reaction depth of the heavy component coal tar under high-pressure hydrogenation conditions, low conversion rate and light oil yield, and the reactor is prone to coking and blockage. Second, the vacuum separation system adopts a single-stage vacuum method, with large wear, complex control procedures, and high inspection and maintenance costs for the vacuum system. Third, there is no feed mixer internal component in the reactor, resulting in poor mixing effect of hydrogen, solid particles, and coal tar at the reactor inlet, and the inlet is prone to blockage. The above problems lead to the current unsatisfactory operation of the imported (VCC) process in China. The overall economic benefit is not very different from that of the coal tar fixed bed hydrocracking unit, and the device start-up is difficult and it is difficult to operate in a long cycle. Summary of the Invention

[0004] The purpose of the present invention is to provide a coal tar suspension bed coupled fixed bed hydrocracking device to solve the problems of easy blockage of the reactor feed system and easy wear of the vacuum system caused by single-stage vacuum in the existing suspension bed coupled fixed bed hydrocracking device.

[0005] Another purpose of the present invention is to provide a coal tar suspension bed coupled fixed bed hydrocracking process to solve the problems of low conversion rate of heavy component coal tar and low light oil yield and reactor coking and blockage in the existing suspension bed coupled fixed bed hydrocracking process.

[0006] The technical solution adopted by the present invention is a coal tar suspension bed coupled fixed bed hydrocracking unit, which includes a catalyst storage tank. The outlet of the catalyst storage tank is connected to a catalyst mixing tank, and the outlet of the catalyst mixing tank is connected to a catalyst feed pump. It also includes a coal tar buffer tank. The outlet of the coal tar buffer tank is connected to the inlet of a slurry feed pump, and the outlet of the slurry feed pump is connected to a first heating furnace. The first heating furnace is connected to a hydrogen heating furnace, and the hydrogen heating furnace is connected to a first suspension bed reactor. The coal tar buffer tank is also connected to a first vacuum tower. The bottom inlet of the first vacuum tower is connected to a second heating furnace, and the second heating furnace is connected to a hot low-pressure separator. The outlet of the first suspension bed reactor is connected to the inlet of a second suspension bed reactor, and the outlet of the second suspension bed reactor is connected to a hot high-pressure separator. The hot high-pressure separator is respectively connected to a cyclone separator and a hot medium-pressure separator. The top outlet of the cyclone separator is connected to a fixed bed reactor, and the bottom outlet of the fixed bed reactor is connected to a first hot high-pressure separator. The bottom and top of the first hot high-pressure separator are respectively connected to an atmospheric fractionating tower and a cold high-pressure separator. The bottom of the atmospheric fractionating tower is connected to a feed pump, and the feed pump is connected to a third heating furnace. The third heating furnace is connected to a fixed bed vacuum fractionating tower. The fixed bed vacuum fractionating tower is connected to a slurry buffer tank. The slurry buffer tank is connected to a hydrocracking feed pump, and the hydrocracking feed pump is connected to a fourth heating furnace. The cold high-pressure separator is respectively connected to a recycle hydrogen buffer tank and the atmospheric fractionating tower, and the recycle hydrogen buffer tank is connected to a recycle hydrogen compressor.

[0007] The characteristics of the present invention also lie in that

[0008] The hot medium-pressure separator is also connected to the hot low-pressure separator. The bottom material outlet of the hot low-pressure separator is respectively connected to the second heating furnace and the cyclone separator. The outlet of the catalyst feed pump is connected to the first suspension bed reactor. The fourth heating furnace is also connected to the fixed bed reactor. The slurry buffer tank is also connected to the catalyst mixing tank.

[0009] The catalyst feed pump, hydrogen heating furnace, second heating furnace, first suspension bed reactor, second suspension bed reactor, hot high-pressure separator, cyclone separator, fixed bed reactor, and recycle hydrogen compressor are all respectively connected to a fresh hydrogen compressor.

[0010] Another technical solution adopted by the present invention is a coal tar suspension bed coupled fixed bed hydrocracking process, which is specifically implemented according to the following steps:

[0011] Step 1: Mix the coal tar suspension bed hydrocracking catalyst with the raw material to obtain a catalyst slurry. After the catalyst slurry and the hydrogenation tail oil at the bottom of the fixed bed vacuum fractionating tower are mixed, they enter the catalyst mixing tank and are fully mixed to obtain a catalyst mixed raw material.

[0012] Step 2, the catalyst mixed raw material obtained in step 1 is pressurized to 15-22.0MPa by a catalyst feed pump; the raw oil in the coal tar buffer tank is pressurized to 15-22.5MPa by an oil slurry feed pump, mixed with hydrogen and then enters the first heating furnace, heated to 250-300° C. by the first heating furnace, and then mixed with high-temperature hydrogen (temperature at 500-550° C.) and the catalyst mixed raw material to obtain a mixed raw oil, which enters the first suspended bed reactor;

[0013] Step 3, the mixed crude oil enters the first suspension bed reactor for reaction, and the reaction temperature inside the first suspension bed reactor is controlled by cooling hydrogen in the suspension bed reactor; the inlet temperature of the first suspension bed reactor is controlled not to exceed 445°C, and the outlet temperature of the first suspension bed reactor is controlled not to exceed 465°C. The outlet of the first suspension bed reactor uses cooling oil to adjust the inlet temperature of the second suspension bed reactor, and the inlet temperature of the second suspension bed reactor is controlled between 445°C and 450°C;

[0014] Step 4, the material at the outlet of the second suspension bed reactor is subjected to a two-stage pressure reduction treatment in a hot high-pressure separator and a hot medium-pressure separator, and gas, liquid and solid are separated at the same time;

[0015] Step 5, the material at the bottom outlet of the hot medium-pressure separator enters the hot low-pressure separator, and then enters the first vacuum tower for material separation after being heated by the second heating furnace. The material at the top of the first vacuum tower is sent out of the device, the solid-free material produced in the middle enters the coal tar flushing tank, and the solid-containing material at the bottom is made into coal tar and sent out of the device;

[0016] Step 6, the material coming out of the top of the hot high-pressure separator enters the cyclone separator, and after the solid particles are separated, they are mixed with the hot oil coming out of the fourth heating furnace and then enter the fixed bed reactor;

[0017] Step 7, the material at the bottom outlet of the fixed bed reactor is cooled by two heat exchangers and then enters the first hot high-pressure separator, and the gas at the top of the first hot high-pressure separator is cooled and then enters the cold high-pressure separator; the materials at the bottom of the first hot high-pressure separator and the cold high-pressure separator are mixed and then enter the atmospheric pressure fractionation tower, and the gas at the top of the cold high-pressure separator enters the circulating hydrogen buffer tank, and then enters the circulating hydrogen compressor to increase the pressure and then be recycled in the system;

[0018] Step 8, the top of the atmospheric distillation tower produces light naphtha products, and the middle part produces heavy naphtha products; the outlet material at the bottom of the atmospheric distillation tower is pressurized by a feed pump and enters the third heating furnace for heating, and then enters the fixed-bed vacuum distillation tower, the top of the fixed-bed vacuum distillation tower produces naphtha, the middle part produces diesel blending components, and the bottom material enters the oil slurry buffer tank;

[0019] Step 9, the heavy oil in the oil slurry buffer tank enters the fourth heating furnace after being pressurized by the hydrocracking feed pump, and then enters the fixed bed hydrogenation reactor to perform a hydrocracking reaction;

[0020] Step 10, the recycle hydrogen coming out from the top of the recycle hydrogen buffer tank enters the recycle hydrogen compressor for pressure boosting; after being pressure-boosted by the recycle hydrogen compressor, it is mixed with the hydrogen whose pressure is boosted to 15 - 23.0 MPa by the fresh hydrogen compressor and then used as cold hydrogen and recycle hydrogen for each cold hydrogen inlet of the first ebullated bed reactor, the second ebullated bed reactor, the fixed bed reactor, and the hot high-pressure separator.

[0021] In Step 1, the raw material is coal tar or coal-oil slurry, and the mass ratio of the coal tar ebullated bed hydrocracking catalyst to coal tar is 0.005 - 0.02:1; the mass ratio of the coal tar ebullated bed hydrocracking catalyst to coal-oil slurry is 0.02 - 0.25:1.

[0022] The beneficial effects of the present invention are:

[0023] For the coal tar ebullated bed coupled fixed bed hydrocracking process of the present invention, the ebullated bed and the fixed bed are coupled. On the one hand, by replacing the adsorbent that does not have a catalytic effect in the coal tar ebullated bed hydrogenation process with a catalyst with coal as the carrier and loaded with iron-based compounds, while improving the conversion rate of coal tar and the light oil yield, it has the function of adsorbing the colloids generated by the side reactions of coal tar hydrocracking, can send the colloids out of the reactor in time, ensure that the reactor maintains a good operating state, and avoid coking and blockage; on the other hand, the material at the outlet of the ebullated bed reactor undergoes three-stage pressure reduction through the hot high-pressure separator, the hot medium-pressure separator, and the hot low-pressure separator, gradually reducing the pressure, reducing the gasification rate of the liquid and the flow rate of the liquid, and effectively solving the problem of wear of the single-stage pressure reduction system; on the other hand, the catalyst of the present invention is directly mixed with the raw material (coal tar or coal) and the hydrogenated tail oil and boosted by a pump, the coal tar is boosted by a pump alone and then mixed with hydrogen and heated, and then these materials are mixed at the reactor inlet, effectively solving the problem of easy blockage of the feed mixing system, and at the same time reducing the wear of the heating furnace tubes.

[0024] In addition, compared with the two independent hydrogenation processes and two sets of devices of the ebullated bed and the fixed bed, the two-stage hydrogenation of the ebullated bed and the fixed bed in series in the present invention allows hydrogen to pass through once, shortening the process flow, reducing the hydrogen loss, and being able to make full use of the reaction heat energy and high-pressure kinetic energy of the ebullated bed hydrocracking, reducing most of the high-pressure investment, reducing the energy consumption, and saving part of the cost of building a fixed bed separately. Description of the Drawings

[0025] Figure 1 is the structural diagram of a coal tar ebullated bed coupled fixed bed hydrocracking device of the present invention.

[0026] In the figure, 1. catalyst storage tank, 2. catalyst mixing tank, 3. catalyst feed pump, 4. coal tar buffer tank, 5. slurry feed pump, 6. first heating furnace, 7. hydrogen heating furnace, 8. first suspension bed reactor, 9. first vacuum tower, 10. second heating furnace, 11. hot low-pressure separator, 12. second suspension bed reactor, 13. hot high-pressure separator, 14. cyclone separator, 15. fixed bed reactor, 16. first hot high-pressure separator, 17. cold high-pressure separator, 18. atmospheric fractionating tower, 19. feed pump, 20. third heating furnace, 21. fixed bed vacuum fractionating tower, 22. slurry buffer tank, 23. hydrocracking feed pump, 24. fourth heating furnace, 25. hot medium-pressure separator, 26. recycle hydrogen buffer tank, 27. recycle hydrogen compressor, 28. fresh hydrogen compressor. Detailed implementation mode

[0027] The present invention will be described in detail below in conjunction with the accompanying drawings and specific implementation modes.

[0028] A coal tar suspension bed coupled with a fixed bed hydrocracking device of the present invention, as Figure 1 shown, includes a catalyst storage tank 1, the outlet of the catalyst storage tank 1 is connected to the catalyst mixing tank 2, and the outlet of the catalyst mixing tank 2 is connected to the catalyst feed pump 3;

[0029] It further includes a coal tar buffer tank 4, the outlet of the coal tar buffer tank 4 is connected to the inlet of the slurry feed pump 5, the outlet of the slurry feed pump 5 is connected to the first heating furnace 6, the first heating furnace 6 is connected to the hydrogen heating furnace 7, and the hydrogen heating furnace 7 is connected to the first suspension bed reactor 8;

[0030] The outlet of the catalyst feed pump 3 is connected to the first suspension bed reactor 8, the coal tar buffer tank 4 is also connected to the first vacuum tower 9, the bottom inlet of the first vacuum tower 9 is connected to the second heating furnace 10, and the second heating furnace 10 is connected to the hot low-pressure separator 11;

[0031] The outlet of the first suspension bed reactor 8 is connected to the inlet of the second suspension bed reactor 12. The outlet of the second suspension bed reactor 12 is connected to the hot high-pressure separator 13. The hot high-pressure separator 13 is respectively connected to the cyclone separator 14 and the hot medium-pressure separator 25. The top outlet of the cyclone separator 14 is connected to the fixed-bed reactor 15 through a pipeline. The bottom outlet of the fixed-bed reactor 15 is connected to the first hot high-pressure separator 16. The bottom and top outlet pipelines of the first hot high-pressure separator 16 are respectively connected to the atmospheric distillation column 18 and the cold high-pressure separator 17 after pressure reduction. Naphtha products are produced in the middle of the atmospheric distillation column 18. The bottom of the atmospheric distillation column 18 is connected to the feed pump 19. The feed pump 19 is connected to the third heating furnace 20. The third heating furnace 20 is connected to the fixed-bed vacuum distillation column 21. Diesel products are produced in the middle of the fixed-bed vacuum distillation column 21, naphtha products are produced at the top, and tail oil is produced at the bottom. The fixed-bed vacuum distillation column 21 is connected to the slurry buffer tank 22. The slurry buffer tank 22 is connected to the hydrocracking feed pump 23. The hydrocracking feed pump 23 is connected to the fourth heating furnace 24. The fourth heating furnace 24 is also connected to the fixed-bed reactor 15; the slurry buffer tank 22 is also connected to the catalyst mixing tank 2;

[0032] The cold high-pressure separator 17 is respectively connected to the recycle hydrogen buffer tank 26 and the atmospheric distillation column 18. The recycle hydrogen buffer tank 26 is connected to the recycle hydrogen compressor 27. The hot medium-pressure separator 25 is also connected to the hot low-pressure separator 11. The bottom material outlet of the hot low-pressure separator 11 is respectively connected to the second heating furnace 10 and the cyclone separator 14.

[0033] The catalyst feed pump 3, the hydrogen heating furnace 7, the second heating furnace 10, the first suspension bed reactor 8, the second suspension bed reactor 12, the hot high-pressure separator 13, the cyclone separator 14, the fixed-bed reactor 15, and the recycle hydrogen compressor 27 are all respectively connected to the new hydrogen compressor 28.

[0034] A coal tar suspension bed coupled fixed-bed hydrocracking process of the present invention is specifically implemented according to the following steps:

[0035] Step 1: Mix the coal tar suspension bed hydrocracking catalyst with the raw material to obtain a catalyst slurry; after mixing the catalyst slurry with the hydrogenation tail oil at the bottom of the fixed-bed vacuum distillation column 21, it enters the catalyst mixing tank 2 for thorough mixing to obtain a catalyst mixed raw material;

[0036] The raw material is coal tar or coal-oil slurry (kerosene ratio 1 - 45:50 - 99);

[0037] The mass ratio of the coal tar suspension bed hydrocracking catalyst to coal tar is 0.005 - 0.02:1;

[0038] The mass ratio of the coal tar suspension bed hydrocracking catalyst to the coal-oil slurry is 0.02 - 0.25:1;

[0039] The coal tar suspension bed hydrocracking catalyst is a catalyst disclosed in a Chinese patent (application number 202010265211.3, publication number CN111420671A);

[0040] Step 2, the catalyst mixed raw material obtained in step 1 is pressurized to 15-22.0MPa by a catalyst feed pump 3; the raw oil in the coal tar buffer tank 4 is pressurized to 15-22.5MPa by an oil slurry feed pump 5, mixed with hydrogen and then enters the first heating furnace 6, heated to 250-300° C. by the first heating furnace 6, and then mixed with high-temperature hydrogen (temperature at 500-550° C.) and the catalyst mixed raw material pressurized in step 1 to obtain a mixed raw oil, which enters the first suspended bed reactor 8;

[0041] The mixed feedstock oil temperature at the inlet of the first suspension bed reactor 8 is controlled at 420-445°C, and the outlet temperature is controlled at 450-465°C;

[0042] Step 3, the mixed crude oil enters the first suspension bed reactor 8 for reaction, and the reaction temperature inside the first suspension bed reactor 8 is controlled by cooling hydrogen in the suspension bed reactor; the inlet temperature of the first suspension bed reactor 8 is controlled not to exceed 445° C., and the outlet temperature of the first suspension bed reactor 8 is controlled not to exceed 465° C. The outlet of the first suspension bed reactor 8 is adjusted with cooling oil to the inlet temperature of the second suspension bed reactor 12, and the inlet temperature of the second suspension bed reactor 12 is controlled to be between 445° C. and 450° C.;

[0043] Step 4, the material at the outlet of the second suspension bed reactor 12 is subjected to a two-stage pressure reduction treatment in a hot high-pressure separator 13 and a hot medium-pressure separator 25, and gas, liquid and solid are separated at the same time;

[0044] Step 5, the material at the bottom outlet of the hot medium-pressure separator 25 enters the hot low-pressure separator 11, and then enters the first vacuum tower 9 for material separation after being heated by the second heating furnace 10. The material delivery device is sent out from the top of the first vacuum tower 9, the solid-free material produced in the middle enters the coal tar flushing tank 4, and the solid-containing material at the bottom is made into coal tar and sent out;

[0045] Step 6, the material coming out of the top of the hot high-pressure separator 13 enters the cyclone separator 14, and after the solid particles are separated, they are mixed with the hot oil coming out of the fourth heating furnace 24 and then enter the fixed bed reactor 15;

[0046] Step 7: The material at the bottom outlet of the fixed-bed reactor 15 enters the first hot high-pressure separator 16 after being cooled by two heat exchangers. The gas at the top of the first hot high-pressure separator 16 enters the cold high-pressure separator 17 after being cooled. The materials at the bottoms of the first hot high-pressure separator 16 and the cold high-pressure separator 17 are mixed and then enter the atmospheric fractionating column 18. The gas at the top of the cold high-pressure separator 17 enters the recycle hydrogen buffer tank 26 and then enters the recycle hydrogen compressor 27 to be pressurized and recycled in the system.

[0047] Step 8: The light naphtha product is produced at the top of the atmospheric fractionating column 18, and the heavy naphtha product is produced in the middle. The material at the bottom outlet of the atmospheric fractionating column 18 is pressurized by the feed pump 19 and then enters the third heating furnace 20 for heating, and then enters the fixed-bed vacuum fractionating column 21. The naphtha is produced at the top of the fixed-bed vacuum fractionating column 21, the diesel blending component is produced in the middle, and the bottom material enters the slurry buffer tank 22.

[0048] Step 9: The heavy oil in the slurry buffer tank 22 is pressurized by the hydrocracking feed pump 23 and then enters the fourth heating furnace 24, and then enters the fixed-bed reactor 15 for hydrocracking reaction.

[0049] Step 10: The recycle hydrogen coming out from the top of the recycle hydrogen buffer tank 26 enters the recycle hydrogen compressor 27 for pressurization. After being pressurized by the recycle hydrogen compressor 27, it is mixed with the hydrogen pressurized to 15 - 23.0 MPa by the fresh hydrogen compressor 28 and then used as cold hydrogen and recycle hydrogen to be supplied to the cold hydrogen inlets of the first suspension bed reactor 8, the second suspension bed reactor 12, the fixed-bed reactor 15, and the hot high-pressure separator 13.

[0050] Example 1

[0051] A coal tar suspension bed coupled fixed-bed hydrocracking process of the present invention is specifically implemented according to the following steps:

[0052] Step 1: Mix the coal tar suspension bed hydrocracking catalyst with the raw material to obtain a catalyst slurry. The catalyst slurry and the hydrogenation tail oil at the bottom of the fixed-bed vacuum fractionating column 21 are mixed and then enter the catalyst mixing tank 2 for sufficient mixing to obtain a catalyst mixed raw material.

[0053] The raw material is coal tar.

[0054] The mass ratio of the coal tar suspension bed hydrocracking catalyst to coal tar is 0.005:1.

[0055] The coal tar suspension bed hydrocracking catalyst is the catalyst disclosed in Chinese Patent (application number 202010265211.3, publication number CN111420671A).

[0056] Step 2, the catalyst mixed raw material obtained in step 1 is pressurized to 22.0 MPa by a catalyst feed pump 3; the raw oil in the coal tar buffer tank 4 is pressurized to 22.5 MPa by an oil slurry feed pump 5, mixed with hydrogen and then enters the first heating furnace 6, heated to 300° C. by the first heating furnace 6, and then mixed with high-temperature hydrogen (temperature at 550° C.) and the catalyst mixed raw material pressurized in step 1 to obtain a mixed raw oil, which enters the first suspended bed reactor 8;

[0057] The mixed feedstock oil temperature at the inlet of the first suspension bed reactor 8 is controlled at 445°C, and the outlet temperature is controlled at 465°C;

[0058] Step 3, the mixed crude oil enters the first suspension bed reactor 8 for reaction, and the reaction temperature inside the first suspension bed reactor 8 is controlled by cooling hydrogen in the suspension bed reactor; the inlet temperature of the first suspension bed reactor 8 is controlled not to exceed 445° C., and the outlet temperature of the first suspension bed reactor 8 is controlled not to exceed 465° C. The outlet of the first suspension bed reactor 8 is adjusted with cooling oil to the inlet temperature of the second suspension bed reactor 12, and the inlet temperature of the second suspension bed reactor 12 is controlled to be 450° C.;

[0059] Step 4, the material at the outlet of the second suspension bed reactor 12 is subjected to a two-stage pressure reduction treatment in a hot high-pressure separator 13 and a hot medium-pressure separator 25, and gas, liquid and solid are separated at the same time;

[0060] Step 5, the material at the bottom outlet of the hot medium-pressure separator 25 enters the hot low-pressure separator 11, and then enters the first vacuum tower 9 for material separation after being heated by the second heating furnace 10. The material at the top of the first vacuum tower 9 is sent out of the device, the solid-free material produced in the middle enters the heavy oil buffer tank 4, and the solid-containing material at the bottom is made into coal tar and sent out of the device;

[0061] Step 6, the material coming out of the top of the hot high-pressure separator 13 enters the cyclone separator 14, and after the solid particles are separated, they are mixed with the hot oil from the fourth heating furnace 24 and then enter the fixed bed reactor 15;

[0062] Step 7, the material at the bottom outlet of the fixed bed reactor 15 is cooled by two heat exchangers and then enters the first hot high-pressure separator 16, and the gas at the top of the first hot high-pressure separator 16 enters the cold high-pressure separator 17 after being cooled; the materials at the bottom of the first hot high-pressure separator 16 and the cold high-pressure separator 17 are mixed and then enter the atmospheric distillation tower 18, and the gas at the top of the cold high-pressure separator 17 enters the circulating hydrogen buffer tank 26, and then enters the circulating hydrogen compressor 27 for pressurization and then is recycled in the system;

[0063] Step 8: Light naphtha product is produced at the top of the atmospheric fractionating column 18, and heavy naphtha product is produced in the middle; the material at the bottom outlet of the atmospheric fractionating column 18 is pressurized by the feed pump 19 and then enters the third heating furnace 20 for heating, and then enters the fixed-bed vacuum fractionating column 21. Naphtha is produced at the top of the fixed-bed vacuum fractionating column 21, diesel blending components are produced in the middle, and the bottom material enters the slurry buffer tank 22;

[0064] Step 9: The heavy oil in the slurry buffer tank 22 is pressurized by the hydrocracking feed pump 23 and then enters the fourth heating furnace 24, and then enters the fixed-bed hydroreactor 15 for hydrocracking reaction;

[0065] Step 10: The recycle hydrogen coming out from the top of the recycle hydrogen buffer tank 26 enters the recycle hydrogen compressor 27 for pressurization; after being pressurized by the recycle hydrogen compressor 27, it is mixed with the hydrogen pressurized to 23.0 MPa by the new hydrogen compressor 28 and then used as cold hydrogen and recycle hydrogen to be supplied to the cold hydrogen inlets of the first ebullated bed reactor 8, the second ebullated bed reactor 12, the fixed-bed reactor 15, and the hot high-pressure separator 13.

[0066] Example 2

[0067] A coal tar ebullated bed coupled with fixed-bed hydrocracking process of the present invention is specifically implemented according to the following steps:

[0068] Step 1: Mix the coal tar ebullated bed hydrocracking catalyst with the raw material to obtain a catalyst slurry; after the catalyst slurry is mixed with the hydrogenated tail oil at the bottom of the fixed-bed vacuum fractionating column 21, it enters the catalyst mixing tank 2 for thorough mixing to obtain a catalyst mixed raw material;

[0069] The raw material is coal tar;

[0070] The mass ratio of the coal tar ebullated bed hydrocracking catalyst to coal tar is 0.01:1;

[0071] The coal tar ebullated bed hydrocracking catalyst is the catalyst disclosed in Chinese Patent (application number: 202010265211.3, publication number: CN111420671A);

[0072] Step 2: Pressurize the catalyst mixed raw material obtained in Step 1 to 22.0 MPa by the catalyst feed pump 3; the raw material oil in the coal tar buffer tank 4 is pressurized to 22.5 MPa by the slurry feed pump 5, mixed with hydrogen, enters the first heating furnace 6, is heated to 300 °C in the first heating furnace 6, and then mixed with high-temperature hydrogen (temperature at 550 °C) and the catalyst mixed raw material pressurized in Step 1 to obtain a mixed raw material oil, which enters the first ebullated bed reactor 8;

[0073] The temperature of the mixed raw material oil at the inlet of the first ebullated bed reactor 8 is controlled at 445 °C, and the outlet temperature is controlled at 465 °C;

[0074] In Step 3, the mixed feedstock oil enters the first suspension bed reactor 8 for reaction. The reaction temperature inside the first suspension bed reactor 8 is controlled by the intercooling hydrogen in the suspension bed reactor. The inlet temperature of the first suspension bed reactor 8 is controlled not to exceed 445 °C, and the outlet temperature of the first suspension bed reactor 8 is controlled not to exceed 465 °C. The outlet of the first suspension bed reactor 8 uses cold oil to adjust the inlet temperature of the second suspension bed reactor 12, and the inlet temperature of the second suspension bed reactor 12 is controlled to be 450 °C.

[0075] In Step 4, the outlet material of the second suspension bed reactor 12 undergoes two-stage pressure reduction treatment through the hot high-pressure separator 13 and the hot medium-pressure separator 25, and at the same time, gas, liquid, and solid are separated.

[0076] In Step 5, the material at the bottom outlet of the hot medium-pressure separator 25 enters the hot low-pressure separator 11, and then enters the first vacuum tower 9 for material separation after being heated by the second heating furnace 10. The top material of the first vacuum tower 9 is sent out of the device, the solid-free material produced in the middle enters the heavy oil buffer tank 4, and the solid-containing material at the bottom is made into coal tar pitch and sent out of the device.

[0077] In Step 6, the material coming out of the top of the hot high-pressure separator 13 enters the cyclone separator 14. After the solid particles are separated, it is mixed with the hot oil coming out of the fourth heating furnace 24 and then enters the fixed bed reactor 15.

[0078] In Step 7, the material at the bottom outlet of the fixed bed reactor 15 is cooled by two heat exchangers and then enters the first hot high-pressure separator 16. The gas at the top of the first hot high-pressure separator 16 is cooled and then enters the cold high-pressure separator 17. The materials at the bottoms of the first hot high-pressure separator 16 and the cold high-pressure separator 17 are mixed and then enter the atmospheric fractionating tower 18. The gas at the top of the cold high-pressure separator 17 enters the recycle hydrogen buffer tank 26, and then enters the recycle hydrogen compressor 27 to be pressurized and recycled in the system.

[0079] In Step 8, light naphtha products are produced at the top of the atmospheric fractionating tower 18, and heavy naphtha products are produced in the middle. The material at the bottom outlet of the atmospheric fractionating tower 18 is pressurized by the feed pump 19 and then enters the third heating furnace 20 for heating, and then enters the fixed bed vacuum fractionating tower 21. Naphtha is produced at the top of the fixed bed vacuum fractionating tower 21, diesel blending components are produced in the middle, and the bottom material enters the slurry buffer tank 22.

[0080] In Step 9, the heavy oil in the slurry buffer tank 22 is pressurized by the hydrocracking feed pump 23 and then enters the fourth heating furnace 24, and then enters the fixed bed hydrocracking reactor 15 for hydrocracking reaction.

[0081] Step 10: The recycle hydrogen coming out from the top of the recycle hydrogen buffer tank 26 enters the recycle hydrogen compressor 27 for pressure boosting; after being pressure-boosted by the recycle hydrogen compressor 27, it is mixed with the hydrogen whose pressure is boosted to 23.0 MPa by the fresh hydrogen compressor 28 and then used as cold hydrogen and recycle hydrogen to each cold hydrogen port of the first ebullated bed reactor 8, the second ebullated bed reactor 12, the fixed bed reactor 15, and the hot high-pressure separator 13.

[0082] The products obtained through Example 1 and Example 2 are respectively liquefied petroleum gas, naphtha, high-quality diesel blending component oil, and coal tar pitch. Table 1 shows the oil yields of the coal tar ebullated bed coupled fixed bed hydrocracking process in Example 1 and Example 2, and Table 2 shows the comparison of the oil yields of several different coal tar processing processes. It can be seen from Table 1 and Table 2 that for the process of the present invention, both its conversion rate and total liquid yield are relatively high.

[0083] Table 1 Oil Yields of the Coal Tar Ebullated Bed Coupled Fixed Bed Hydrocracking Process

[0084] Example Catalyst dosage Average reaction temperature Reaction pressure Conversion rate of heavy oil Total liquid yield 1 0.5％ 455℃ 20 MPa 76％ 79％ 2 1％ 455℃ 20 MPa 87％ 90％

[0085] Table 2 Comparison of Oil Yields of Several Different Coal Tar Processing Processes

[0086]

Claims

1. A coal tar suspension bed coupled fixed bed hydrocracking process, characterized in that, The implementation is specifically carried out according to the following steps: Step 1: Mix the coal tar suspension bed hydrocracking catalyst with the raw material to obtain a catalyst slurry. After mixing the catalyst slurry with the hydrogenated tail oil at the bottom of the fixed bed vacuum fractionating tower (21), it enters the catalyst mixing tank (2) for thorough mixing to obtain a catalyst mixed raw material; The raw material is coal tar or coal-water slurry. The mass ratio of the coal tar suspension bed hydrocracking catalyst to coal tar is 0.005 - 0.02:1; the mass ratio of the coal tar suspension bed hydrocracking catalyst to coal-water slurry is 0.02 - 0.25:1; Step 2: Boost the pressure of the catalyst mixed raw material obtained in Step 1 to 15 - 22.0 MPa through the catalyst feed pump (3). The raw material oil in the coal tar buffer tank (4) is boosted to 15 - 22.5 MPa through the slurry feed pump (5), mixed with hydrogen, and then enters the first heating furnace (6). After being heated to 250 - 300 °C in the first heating furnace (6), it is mixed with high-temperature hydrogen at 500 - 550 °C and the catalyst mixed raw material to obtain a mixed raw material oil, which enters the first suspension bed reactor (8); Step 3: The mixed raw material oil enters the first suspension bed reactor (8) for reaction. The reaction temperature inside the first suspension bed reactor (8) is controlled by the intermediate cold hydrogen in the suspension bed reactor. Control the inlet temperature of the first suspension bed reactor (8) not to exceed 445 °C, and control the outlet temperature of the first suspension bed reactor (8) not to exceed 465 °C. The outlet of the first suspension bed reactor (8) uses cold oil to adjust the inlet temperature of the second suspension bed reactor (12), and control the inlet temperature of the second suspension bed reactor (12) to be between 445 - 450 °C; Step 4: The outlet material of the second suspension bed reactor (12) undergoes two-stage pressure reduction treatment through the hot high-pressure separator (13) and the hot medium-pressure separator (25), and at the same time, gas, liquid, and solid are separated; Step 5: The bottom outlet material of the hot medium-pressure separator (25) enters the hot low-pressure separator (11), then enters the first vacuum tower (9) for material separation after being heated by the second heating furnace (10). The top material of the first vacuum tower (9) is sent out of the device, the solid-free material produced in the middle enters the coal tar buffer tank (4), and the solid-containing material at the bottom is made into coal pitch and sent out of the device; Step 6: The material coming out of the top of the hot high-pressure separator (13) enters the cyclone separator (14). After separating the solid particles, it is mixed with the hot oil coming out of the fourth heating furnace (24) and then enters the fixed bed reactor (15); Step 7: The bottom outlet material of the fixed bed reactor (15) is cooled by two heat exchangers and then enters the first hot high-pressure separator (16). The gas at the top of the first hot high-pressure separator (16) enters the cold high-pressure separator (17) after being cooled. The bottom materials of the first hot high-pressure separator (16) and the cold high-pressure separator (17) are mixed and then enter the atmospheric fractionating tower (18). The gas at the top of the cold high-pressure separator (17) enters the recycle hydrogen buffer tank (26), and then enters the recycle hydrogen compressor (27) to boost the pressure and is recycled in the system; Step 8, light naphtha product is produced at the top of the atmospheric fractionating column (18), and heavy naphtha product is produced in the middle; the material at the bottom outlet of the atmospheric fractionating column (18) is pressurized by the feed pump (19) and then enters the third heating furnace (20) for heating, and then enters the fixed-bed vacuum fractionating column (21). Naphtha is produced at the top of the fixed-bed vacuum fractionating column (21), diesel blending components are produced in the middle, and the bottom material enters the slurry buffer tank (22); Step 9, the heavy oil in the slurry buffer tank (22) is pressurized by the hydrocracking feed pump (23) and then enters the fourth heating furnace (24), and then enters the fixed-bed hydrocracking reactor (15) for hydrocracking reaction; Step 10, the recycle hydrogen coming out from the top of the recycle hydrogen buffer tank (26) enters the recycle hydrogen compressor (27) for pressurization; after being pressurized by the recycle hydrogen compressor (27), it is mixed with the hydrogen pressurized to 15 - 23.0 MPa by the new hydrogen compressor (28) and then used as cold hydrogen and recycle hydrogen to each cold hydrogen inlet of the first ebullated bed reactor (8), the second ebullated bed reactor (12), the fixed-bed reactor (15), and the hot high-pressure separator (13).

2. The coal tar suspension bed coupled fixed bed hydrocracking process according to claim 1, characterized in that, It is realized by adopting a coal tar suspension bed coupled with a fixed bed hydrocracking unit. The specific structure is as follows: It includes a catalyst storage tank (1), the outlet of the catalyst storage tank (1) is connected to a catalyst mixing tank (2), and the outlet of the catalyst mixing tank (2) is connected to a catalyst feed pump (3); it also includes a coal tar buffer tank (4), the outlet of the coal tar buffer tank (4) is connected to the inlet of a slurry feed pump (5), the outlet of the slurry feed pump (5) is connected to a first heating furnace (6), the first heating furnace (6) is connected to a hydrogen heating furnace (7), and the hydrogen heating furnace (7) is connected to a first suspension bed reactor (8); the coal tar buffer tank (4) is also connected to a first vacuum tower (9), the bottom inlet of the first vacuum tower (9) is connected to a second heating furnace (10), and the second heating furnace (10) is connected to a hot low-pressure separator (11); the outlet of the first suspension bed reactor (8) is connected to the inlet of a second suspension bed reactor (12), the outlet of the second suspension bed reactor (12) is connected to a hot high-pressure separator (13), the hot high-pressure separator (13) is respectively connected to a cyclone separator (14) and a hot medium-pressure separator (25), the top outlet of the cyclone separator (14) is connected to a fixed bed reactor (15), the bottom outlet of the fixed bed reactor (15) is connected to a first hot high-pressure separator (16), the bottom and top of the first hot high-pressure separator (16) are respectively connected to an atmospheric fractionating tower (18) and a cold high-pressure separator (17), the bottom of the atmospheric fractionating tower (18) is connected to a feed pump (19), the feed pump (19) is connected to a third heating furnace (20), the third heating furnace (20) is connected to a fixed bed vacuum fractionating tower (21), the fixed bed vacuum fractionating tower (21) is connected to a slurry buffer tank (22), the slurry buffer tank (22) is connected to a hydrocracking feed pump (23), and the hydrocracking feed pump (23) is connected to a fourth heating furnace (24); the cold high-pressure separator (17) is respectively connected to a recycle hydrogen buffer tank (26) and the atmospheric fractionating tower (18), and the recycle hydrogen buffer tank (26) is connected to a recycle hydrogen compressor (27); the hot medium-pressure separator (25) is also connected to the hot low-pressure separator (11), and the bottom material outlet of the hot low-pressure separator (11) is respectively connected to the second heating furnace (10) and the cyclone separator (14); the outlet of the catalyst feed pump (3) is connected to the first suspension bed reactor (8), and the fourth heating furnace (24) is also connected to the fixed bed reactor (15); the slurry buffer tank (22) is also connected to the catalyst mixing tank (2); the catalyst feed pump (3), the hydrogen heating furnace (7), the second heating furnace (10), the first suspension bed reactor (8), the second suspension bed reactor (12), the hot high-pressure separator (13), the cyclone separator (14), the fixed bed reactor (15), and the recycle hydrogen compressor (27) are all respectively connected to a fresh hydrogen compressor (28).

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