An apparatus and process for coupling direct coal liquefaction with fluidized bed coking and fluidized bed gasification.

Abstract

This invention relates to the field of coal chemical technology, specifically to an apparatus and process for coupling direct coal liquefaction with fluidized bed coking and fluidized bed gasification. The apparatus includes a direct coal liquefaction system, an asphalt feeding system, a coking system, a gasification system, a tar recovery system, and a syngas purification system. This invention improves the total oil yield of direct coal liquefaction by extracting tar components from liquefied asphalt through coking and returning it to hydrogenation. It employs a conversion path of coking oil extraction and gasification carbon removal, completely converting liquefied asphalt into gaseous and liquid products, avoiding solid waste generation. It utilizes self-produced semi-coke to replace external raw coal for gasification hydrogen production, reducing dependence on external coal for gasification and thus lowering hydrogen costs and overall plant carbon emissions. It uses high-temperature solid particle recycling to supply waste heat from gasification to the coking process, forming a cascaded energy utilization system, reducing external heating demand and overall energy consumption.

Description

Technical Field

[0001] This invention relates to the field of coal chemical technology, specifically to an apparatus and process method for coupling direct coal liquefaction with fluidized bed coking and fluidized bed gasification. Background Technology

[0002] Direct coal liquefaction (DCL) is an important method for obtaining liquid fuels and chemicals from coal. In DCL, raw coal undergoes hydrocracking to produce liquefied oil, while liquefied bitumen, comprising approximately 10%-30% of the raw coal's weight, is produced as a byproduct. This bitumen is characterized by high carbon, high sulfur, high ash content, and high viscosity, posing a key challenge to the economic and environmental viability of liquefaction technology.

[0003] Currently, the main methods for processing liquefied asphalt include using it as a cheap fuel, delayed coking, or direct gasification. However, these methods have significant drawbacks: as fuel, direct coal liquefaction asphalt is used directly as boiler fuel, resulting in low energy utilization and severe pollution; as coking feedstock, direct coal liquefaction asphalt enters a delayed coking unit, producing a large amount of low-value, difficult-to-process high-sulfur petroleum coke; and as gasification feedstock, direct coal liquefaction asphalt enters a gasifier, which suffers from unstable gasifier operation due to the coking characteristics of the asphalt.

[0004] Meanwhile, the existing coal direct liquefaction plants have fragmented liquefaction, hydrogen production, and bitumen processing units, resulting in problems such as low system energy utilization efficiency, high hydrogen costs, large carbon emissions, and underutilization of resources.

[0005] To this end, a device and process method for coupling direct coal liquefaction with fluidized bed coking and fluidized bed gasification are proposed. Summary of the Invention

[0006] The purpose of this invention is to provide an apparatus and process method for coupling direct coal liquefaction with fluidized bed coking and fluidized bed gasification, thereby solving the problems of difficult liquefied bitumen treatment, low system energy utilization efficiency, high hydrogen cost, and underutilization of resources in the existing direct coal liquefaction process.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A device for coupling direct coal liquefaction with fluidized bed coking and fluidized bed gasification includes, in sequence,

[0009] The direct coal liquefaction system is used to hydrogenate and liquefy raw coal to produce liquefied oil and high-temperature molten liquefied asphalt;

[0010] An asphalt feeding system is used to stably transport the high-temperature molten liquefied asphalt to the coking system;

[0011] A coking system for pyrolyzing liquefied asphalt into dry distillation gas and semi-coke, the coking system including a fluidized bed coking furnace, the fluidized bed coking furnace operating at a temperature of 400-850℃ and a pressure of 0.05-3.0MPa;

[0012] The gasification system is used to react the semi-coke with pure oxygen and superheated steam to generate crude syngas, and to recycle the high-temperature solid particles generated in the reaction to the coking system to provide reaction heat.

[0013] A tar recovery system is used to separate the pyrolysis gas into heavy tar, light tar, and coking dry gas.

[0014] The syngas purification system is used to wash and cool the crude syngas before sending it to the hydrogen production unit as a hydrogen production feedstock.

[0015] Preferably, the direct coal liquefaction system includes an air separation unit, a direct liquefaction unit, a hydrogenation stabilization unit, a hydrogenation reforming unit, a light hydrocarbon recovery unit, a wastewater treatment unit, and a hydrogen production unit. The oxygen outlet of the air separation unit is connected to the oxygen inlet of the direct liquefaction unit and the fluidized bed gasifier. The asphalt outlet of the direct liquefaction unit is connected to the inlet of the asphalt feeding system. The oil outlet of the direct liquefaction unit is connected to the inlet of the hydrogenation stabilization unit. The outlet of the hydrogenation stabilization unit is connected to the inlet of the hydrogenation reforming unit. The outlet of the hydrogenation reforming unit is connected to the inlet of the light hydrocarbon recovery unit. The inlet of the wastewater treatment unit is connected to the wastewater outlets of the direct liquefaction unit, the hydrogenation stabilization unit, and the hydrogenation reforming unit. The hydrogen outlet of the hydrogen production unit is connected to the hydrogen inlet of the direct liquefaction unit.

[0016] Preferably, the asphalt feeding system includes a liquefied asphalt conveying pump and a liquefied asphalt feeding pump. The inlet of the liquefied asphalt conveying pump is connected to the asphalt outlet of the direct liquefaction unit, the outlet of the liquefied asphalt conveying pump is connected to the inlet of the liquefied asphalt feeding pump, and the outlet of the liquefied asphalt feeding pump is connected to the asphalt inlet of the fluidized bed coking furnace. The asphalt feeding system is equipped with a heat tracing system throughout the process to stably convey the molten asphalt at 250-350℃ discharged from the direct liquefaction unit to the fluidized bed coking furnace.

[0017] Preferably, the operating temperature of the fluidized bed coking furnace is 400-850℃ and the pressure is 0.05-3.0MPa. The coking system is also equipped with a coking cyclone separator and a dry gas circulation fan. The dry gas circulation fan is used to return part of the coking dry gas as a fluidizing medium to the fluidized bed coking furnace.

[0018] Preferably, the gasification system includes a fluidized bed gasifier, the operating temperature of which is 900-1250℃ and the pressure is 0.05-3.0MPa. The gasification system is also equipped with a mixing separator and a gasification cyclone separator. The high-temperature solid particles of 900-1250℃ separated by the gasification cyclone separator are recycled to the fluidized bed coking furnace.

[0019] Preferably, the tar recovery system includes an oil washing tower, an oil washing tower bottom separator, a washing circulation system, a dry gas cooler, and a dry gas separator. The gas outlet of the oil washing tower is connected to the inlet of the dry gas cooler, the outlet of the dry gas cooler is connected to the inlet of the dry gas separator, the bottom oil outlet of the oil washing tower is connected to the inlet of the oil washing tower bottom separator, the heavy tar outlet of the oil washing tower bottom separator is connected to the inlet of the hydrogenation stabilization unit, the inlet of the washing circulation system is connected to the circulating oil outlet of the oil washing tower bottom separator, the outlet of the washing circulation system is connected to the washing oil inlet of the oil washing tower, the light tar outlet of the dry gas separator is connected to the inlet of the hydrogenation reforming unit, and the dry gas outlet of the dry gas separator is connected to the inlet of the dry gas circulation fan.

[0020] Preferably, the syngas purification system includes a Venturi scrubber, a water scrubbing tower, and a black water treatment device. The inlet of the Venturi scrubber is connected to the gas outlet of the gasification cyclone separator, the outlet of the Venturi scrubber is connected to the inlet of the water scrubbing tower, the gas outlet of the water scrubbing tower is connected to the syngas inlet of the hydrogen production unit, the bottom black water outlet of the water scrubbing tower is connected to the inlet of the black water treatment device, and the outlet of the black water treatment device is connected to the washing water inlet of the water scrubbing tower. The syngas purification system is used to wash and cool the crude syngas to a dust content of less than or equal to 10 mg / Nm³.

[0021] A coupled process method for direct coal liquefaction with fluidized bed coking and fluidized bed gasification, based on the aforementioned apparatus for coupled direct coal liquefaction with fluidized bed coking and fluidized bed gasification, and comprising the following steps:

[0022] S100: Raw coal is hydrogenated and liquefied in a direct liquefaction unit to obtain liquefied oil and molten pitch at 250-350℃; S200: The molten asphalt is fed into a fluidized bed coking oven and coking reaction is carried out at 400-850℃ to generate semi-coke and dry distillation gas; S300: The semi-coke is fed into a fluidized bed gasifier and gasified with pure oxygen and superheated steam at 900-1250℃ to generate crude syngas and high-temperature solid particles. S400: Separate the high-temperature solid particles entrained in the crude syngas, and circulate the separated high-temperature solid particles to the fluidized bed coking furnace to provide reaction heat, while the separated crude syngas enters the syngas purification system. S500: The dry distillation gas is separated, washed with oil, and cooled by a tar recovery system to obtain heavy tar, light tar, and coking dry gas; S600: The heavy tar and light tar are returned to the coal direct liquefaction system for processing; the purified syngas is sent to the hydrogen production unit to produce hydrogen, which is then supplied back to the direct liquefaction unit; the black water generated from syngas washing is treated by the black water treatment unit and then recycled.

[0023] Preferably, in step S200, the material residence time is controlled to be 10-50 seconds by adjusting the circulating dry gas volume, and the mass ratio of circulating semi-coke to asphalt is controlled to be 5-50:1.

[0024] Preferably, in step S300, the molar ratio of oxygen to carbon is adjusted to 0.4-1.0:1, and the molar ratio of steam to oxygen is controlled to 0.2-2.0:1.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] By extracting tar components from liquefied bitumen through coking and returning them to hydrogenation, the total oil yield of direct coal liquefaction can be improved. A conversion path involving coking for oil extraction and gasification for carbon removal completely transforms liquefied bitumen into gaseous and liquid products, avoiding the generation of solid waste. Using self-produced semi-coke to replace external raw coal for gasification hydrogen production reduces dependence on external coal for gasification, thereby lowering hydrogen costs and overall plant carbon emissions. High-temperature solid particle recycling supplies waste heat from gasification to the coking process, creating a cascaded energy utilization system that reduces external heating demand and overall energy consumption. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of an apparatus for coupling direct coal liquefaction with fluidized bed coking and fluidized bed gasification according to the present invention.

[0028] In the diagram: 1. Coal direct liquefaction system; 2. Air separation unit; 3. Direct liquefaction unit; 4. Hydrogenation stabilization unit; 5. Hydrogenation reforming unit; 6. Light hydrocarbon recovery unit; 7. Wastewater treatment unit; 8. Hydrogen production unit; 9. Liquefied asphalt transfer pump; 10. Liquefied asphalt feed pump; 11. Fluidized bed coking furnace; 12. Fluidized bed gasifier; 13. Mixing separator; 14. Gasification cyclone separator; 15. Coking cyclone separator; 16. Oil washing tower; 17. Oil washing tower bottom separator; 18. Heavy tar pump; 19. Washing circulating oil pump; 20. Washing oil cooler; 21. Dry gas cooler; 22. Dry gas separator; 23. Light tar pump; 24. Dry gas circulating fan; 25. Venturi scrubber; 26. Water washing tower; 27. Washing tower circulating water pump; 28. Water washing tower bottom pump; 29. ​​Black water treatment unit; 30. Ash water pump. Detailed Implementation

[0029] To ensure a clear and complete description of the technical solutions in the embodiments of the present invention, and to make the features and advantages more apparent and understandable, the specific implementation methods of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] Please see Figure 1 This invention provides an apparatus coupling direct coal liquefaction with fluidized bed coking and fluidized bed gasification, comprising, in sequence: a direct coal liquefaction system 1 for hydrogenating and liquefying raw coal to produce liquefied oil and high-temperature molten liquefied asphalt; an asphalt feeding system for stably conveying the high-temperature molten liquefied asphalt to a coking system; a coking system for pyrolyzing the liquefied asphalt into dry distillation gas and semi-coke, the coking system including a fluidized bed coking furnace 11, the operating temperature of the fluidized bed coking furnace being 400-850℃ and the pressure being 0.05-3.0MPa; a gasification system for reacting semi-coke with pure oxygen and superheated steam to generate crude syngas, and circulating the high-temperature solid particles generated in the reaction to the coking system to provide reaction heat; a tar recovery system for separating the dry distillation gas into heavy tar, light tar, and coking dry gas; and a syngas purification system for washing and cooling the crude syngas before sending it to a hydrogen production unit 8 as a hydrogen production feedstock.

[0032] Specifically, by sequentially connecting direct coal liquefaction, fluidized bed coking, and fluidized bed gasification systems to form a closed loop of materials and energy, on-site conversion of liquefied bitumen is achieved. The high-temperature solid particles generated by the gasification system are used to heat the coking system, reducing dependence on external heat sources. Simultaneously, the semi-coke produced by the coking system is directly used as feedstock for the gasification system, forming an internal resource cycle.

[0033] The coal direct liquefaction system 1 includes an air separation unit 2, a direct liquefaction unit 3, a hydrogenation stabilization unit 4, a hydrogenation reforming unit 5, a light hydrocarbon recovery unit 6, a wastewater treatment unit 7, and a hydrogen production unit 8. The oxygen outlet of the air separation unit 2 is connected to the oxygen inlet of the direct liquefaction unit 3 and the fluidized bed gasifier 12. The asphalt outlet of the direct liquefaction unit 3 is connected to the inlet of the asphalt feeding system. The oil outlet of the direct liquefaction unit 3 is connected to the inlet of the hydrogenation stabilization unit 4. The outlet of the hydrogenation stabilization unit 4 is connected to the inlet of the hydrogenation reforming unit 5. The outlet of the hydrogenation reforming unit 5 is connected to the inlet of the light hydrocarbon recovery unit 6. The inlet of the wastewater treatment unit 7 is connected to the wastewater outlets of the direct liquefaction unit 3, the hydrogenation stabilization unit 4, and the hydrogenation reforming unit 5. The hydrogen outlet of the hydrogen production unit 8 is connected to the hydrogen inlet of the direct liquefaction unit 3.

[0034] Specifically, by reconnecting the hydrogen outlet of the hydrogen production unit 8 to the direct liquefaction unit 3, a self-sufficient hydrogen loop is constructed within the system. The air separation unit 2 simultaneously supplies oxygen to both the liquefaction and gasification units, optimizing the configuration of utilities. The wastewater treatment unit 7 centrally treats wastewater from each unit, achieving source control of pollutants.

[0035] The asphalt feeding system includes a liquefied asphalt delivery pump 9 and a liquefied asphalt feeding pump 10. The inlet of the liquefied asphalt delivery pump 9 is connected to the asphalt outlet of the direct liquefaction unit 3, the outlet of the liquefied asphalt delivery pump 9 is connected to the inlet of the liquefied asphalt feeding pump 10, and the outlet of the liquefied asphalt feeding pump 10 is connected to the asphalt inlet of the fluidized bed coking furnace 11. The asphalt feeding system is equipped with a heating system throughout the process to stably transport the molten asphalt at 250-350℃ discharged from the direct liquefaction unit 3 to the fluidized bed coking furnace 11.

[0036] Specifically, by setting up a series of delivery pumps and feed pumps and equipping the entire process with a heating system, the engineering problem of high-viscosity, high-freezing-point, high-temperature molten asphalt easily solidifying and clogging during pipeline transportation was solved. This solution ensures that liquefied asphalt can be stably and controllably transported from the direct liquefaction unit 3 to the downstream fluidized bed coking furnace 11, guaranteeing the continuous and stable operation of the entire system.

[0037] The operating temperature of the fluidized bed coking furnace 11 is 400-850℃ and the pressure is 0.05-3.0MPa. The coking system is also equipped with a coking cyclone separator 15 and a dry gas circulation fan 24. The dry gas circulation fan 24 is used to return part of the coking dry gas as a fluidizing medium to the fluidized bed coking furnace 11.

[0038] Specifically, by utilizing its own generated coking dry gas as a fluidizing medium, the material within the coking system is fluidized without the need to introduce external inert gas. The coking cyclone separator 15 captures and returns entrained solid particles to the furnace, extending the residence time of solids within the furnace and improving carbon conversion efficiency. This design enhances the heat and mass transfer processes within the fluidized bed and achieves self-supply of the reaction medium.

[0039] The gasification system includes a fluidized bed gasifier 12, which operates at a temperature of 900-1250℃ and a pressure of 0.05-3.0MPa. The gasification system is also equipped with a mixing separator 13 and a gasification cyclone separator 14. The high-temperature solid particles of 900-1250℃ separated by the gasification cyclone separator 14 are recycled to the fluidized bed coking furnace 11.

[0040] Specifically, the high-temperature solid particles generated by the gasification reaction are recycled to the fluidized bed coking furnace 11 through the gasification cyclone separator 14, establishing a direct energy coupling loop across the system. This feature efficiently transfers the excess sensible heat of the gasification process to the endothermic coking process, realizing the cascade utilization of energy and avoiding the additional fuel consumption and investment required by setting up a separate external heating furnace.

[0041] The tar recovery system includes an oil washing tower 16, a bottom separator of the oil washing tower 16, a washing circulation system, a dry gas cooler 21, and a dry gas separator 22. The gas outlet of the oil washing tower 16 is connected to the inlet of the dry gas cooler 21, the outlet of the dry gas cooler 21 is connected to the inlet of the dry gas separator 22, the bottom oil outlet of the oil washing tower 16 is connected to the inlet of the bottom separator of the oil washing tower 16, the heavy tar outlet of the bottom separator of the oil washing tower 16 is connected to the inlet of the hydrogenation stabilization unit 4, the inlet of the washing circulation system is connected to the circulating oil outlet of the bottom separator of the oil washing tower 16, the outlet of the washing circulation system is connected to the washing oil inlet of the oil washing tower 16, the light tar outlet of the dry gas separator 22 is connected to the inlet of the hydrogenation reforming unit 5, and the dry gas outlet of the dry gas separator 22 is connected to the inlet of the dry gas circulation fan 24.

[0042] Specifically, the tar recovery system finely separates the carbonized gas into heavy tar, light tar, and coking dry gas. The heavy tar and light tar are sent to the hydrostabilization unit 4 and hydrorefining unit 5, respectively, achieving co-processing of coking and liquefaction products and directly improving the overall yield of high-value oil products in the plant. The separated dry gas, in addition to being partially used as a fluidizing medium, can be used as fuel or chemical feedstock, realizing the graded high-value utilization of the products.

[0043] The syngas purification system includes a Venturi scrubber 25, a water scrubbing tower 26, and a black water treatment device 29. The inlet of the Venturi scrubber 25 is connected to the gas outlet of the gasification cyclone separator 14, the outlet of the Venturi scrubber 25 is connected to the inlet of the water scrubbing tower 26, the gas outlet of the water scrubbing tower 26 is connected to the syngas inlet of the hydrogen production unit 8, the bottom black water outlet of the water scrubbing tower 26 is connected to the inlet of the black water treatment device 29, and the outlet of the black water treatment device 29 is connected to the washing water inlet of the water scrubbing tower 26. The syngas purification system is used to wash and cool the crude syngas to a dust content of less than or equal to 10 mg / Nm³.

[0044] Specifically, the two-stage wet scrubbing process, consisting of a Venturi scrubber 25 and a water scrubbing tower 26, effectively reduces the dust content in the crude syngas, meeting the feed gas quality requirements of the subsequent hydrogen production unit 8. Simultaneously, the black water treatment unit 29 purifies and recycles the scrubbing wastewater, creating a closed-loop water circulation system for the syngas purification unit. This significantly reduces fresh water consumption and wastewater discharge, improving the system's environmental friendliness.

[0045] Example 2

[0046] Please see Figure 1 This invention provides a coupled process method for direct coal liquefaction with fluidized bed coking and fluidized bed gasification, based on the apparatus for coupling direct coal liquefaction with fluidized bed coking and fluidized bed gasification as described in the above embodiments, and includes the following steps:

[0047] S100: Raw coal is hydrogenated and liquefied in direct liquefaction unit 3 to obtain liquefied oil and molten pitch at 250-350℃;

[0048] S200: Molten asphalt is fed into fluidized bed coking furnace 11 and coking reaction is carried out at 400-850℃ to generate semi-coke and dry distillation gas;

[0049] S300: Semi-coke is fed into fluidized bed gasifier 12 and gasified with pure oxygen and superheated steam at 900-1250℃ to generate crude syngas and high-temperature solid particles.

[0050] S400: Separates the high-temperature solid particles entrained in the crude syngas. The separated high-temperature solid particles are recycled to the fluidized bed coking furnace 11 to provide reaction heat, and the separated crude syngas enters the syngas purification system.

[0051] S500: The dry distillation gas is separated, washed with oil, and cooled by the tar recovery system to obtain heavy tar, light tar, and coking dry gas;

[0052] S600: Heavy tar and light tar are returned to the coal direct liquefaction system 1 for processing; the purified syngas is sent to the hydrogen production unit 8 to produce hydrogen, which is then fed back to the direct liquefaction unit 3; the black water generated from syngas washing is treated by the black water treatment unit 29 and then recycled.

[0053] Specifically, the core energy coupling is achieved by recycling the high-temperature solids produced in the gasification step to the coking step as a heat source. Simultaneously, the tar produced in the coking step is returned to the liquefaction step, and the syngas produced in the gasification step is used to produce hydrogen and returned to the liquefaction step, constructing a closed-loop material recycling system. This method systematically improves the resource conversion efficiency and energy utilization efficiency of coal.

[0054] In step S200, the material residence time is controlled to be 10-50 seconds by adjusting the circulating dry gas volume, and the mass ratio of circulating semi-coke to asphalt is controlled to be 5-50:1.

[0055] Specifically, by limiting two key operating parameters—the circulating dry gas volume and the mass ratio of circulating semi-coke to pitch—the pyrolysis reaction depth of pitch within the fluidized bed coking furnace 11 was precisely controlled. Maintaining the residence time at 10-50 seconds ensured complete pyrolysis of the pitch while preventing excessive cracking. Controlling the mass ratio of circulating semi-coke to pitch at 5-50:1 ensured sufficient solid heat carrier within the coking furnace, maintaining a uniform and stable reaction temperature, thereby optimizing the yield and composition of the dry distillation gas.

[0056] In step S300, the molar ratio of oxygen to carbon is adjusted to 0.4-1.0:1, and the molar ratio of steam to oxygen is controlled to 0.2-2.0:1.

[0057] Specifically, by limiting the molar ratios of oxygen to carbon and steam to oxygen, precise control of the reaction temperature within the fluidized bed gasifier 12 is achieved. A suitable oxygen-to-carbon ratio ensures complete gasification of the semi-coke, while the steam-to-oxygen ratio regulates the reaction temperature and promotes the water-gas reaction, generating more hydrogen. This parameter range ensures that the gasification process produces sufficient high-temperature solid particles (900-1250℃) to meet the process requirements for heating the fluidized bed coking furnace 11 while efficiently producing hydrogen.

[0058] Based on a million-ton oil-grade liquefaction plant using example coal samples, the following are the results of direct coal liquefaction experiments using the demonstration coal samples:

[0059] Raw coal analysis: Industrial analysis: Mad 9.16%, Ad 5.00%, Vdaf 38.71%; Elemental analysis: Cdaf 79.80%, Hdaf 4.87%, H / C atomic ratio 0.73;

[0060] Results of conventional direct liquefaction (benchmark): Liquefied oil yield: ~52.5 wt% (daf) Liquefied bitumen yield: ~30.7 wt%.

[0061] Where Mad refers to air-dried moisture; Ad refers to dried ash; Vdaf refers to dried ash-free volatile matter; Cdaf refers to the mass fraction of carbon in the dried ash-free coal sample; H represents hydrogen atoms, and C represents carbon atoms.

[0062] Effects of implementing the process of this invention:

[0063] Increased oil yield: Coking of bitumen yields approximately 6.67 wt% (to feedstock coal) of tar, which, upon hydroconversion, yields an additional approximately 5.34 wt% of liquefied oil. The total liquefied oil yield increases from 52.5% to approximately 58.06%, representing an absolute increase of 5.56 percentage points and a relative increase of approximately 10.6%.

[0064] Calculation of coal consumption for alternative gasification:

[0065] Assuming that traditional independent gasification hydrogen production uses raw coal with an ash content of 14.5%, and other coal qualities are the same as the demonstration coal sample, the coal consumption per ton of hydrogen is approximately 7.0 tons.

[0066] The system of this invention produces semi-coke through gasification, and can produce 71,000 tons of hydrogen per year, meeting more than 40% of the needs of the example plant.

[0067] Therefore, the annual amount of coal that can be completely replaced by traditional external gasification is: 71,000 tons of hydrogen × 7.0 tons of coal / ton of hydrogen = 497,000 tons.

[0068] The economic benefits achieved by this invention are as follows: After adopting this patented technology, a million-ton oil liquefaction plant can increase oil production by approximately 107,000 tons / year, save 497,000 tons / year in gasification raw material coal procurement costs, and eliminate the cost of high-sulfur coke disposal.

[0069] The resource and environmental benefits achieved by this invention are: saving 497,000 tons / year of coal resources and avoiding corresponding carbon emissions from mining, transportation and conversion; high-ash asphalt is fully recycled and wastewater is discharged at near zero.

[0070] The technical advantages achieved by this invention are: overcoming the technical challenges of economically and efficiently converting high-ash, high-viscosity liquefied asphalt and semi-coke, and realizing a high degree of synergy between energy and materials within the system.

[0071] In summary, this invention, through its unique process coupling and system integration design, has achieved groundbreaking progress in improving product yield, reducing raw material consumption, and realizing clean production, providing a practical solution for the upgrading of coal direct liquefaction technology.

[0072] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A device for coupling direct coal liquefaction with fluidized bed coking and fluidized bed gasification, characterized in that: It includes a coal direct liquefaction system (1) connected in sequence, used to hydrogenate and liquefy raw coal to produce liquefied oil and high-temperature molten liquefied asphalt; An asphalt feeding system is used to stably transport the high-temperature molten liquefied asphalt to the coking system; A coking system for pyrolyzing the liquefied asphalt into dry distillation gas and semi-coke, the coking system including a fluidized bed coking furnace (11), the operating temperature of the fluidized bed coking furnace being 400-850℃ and the pressure being 0.05-3.0MPa; The gasification system is used to react the semi-coke with pure oxygen and superheated steam to generate crude syngas, and to recycle the high-temperature solid particles generated in the reaction to the coking system to provide reaction heat. A tar recovery system is used to separate the pyrolysis gas into heavy tar, light tar, and coking dry gas. Syngas purification system is used to wash and cool the crude syngas before sending it to the hydrogen production unit (8) as a hydrogen production feedstock.

2. The apparatus for coupling direct coal liquefaction with fluidized bed coking and fluidized bed gasification according to claim 1, characterized in that: The coal direct liquefaction system (1) includes an air separation unit (2), a direct liquefaction unit (3), a hydrogenation stabilization unit (4), a hydrogenation reforming unit (5), a light hydrocarbon recovery unit (6), a wastewater treatment unit (7), and a hydrogen production unit (8). The oxygen outlet of the air separation unit (2) is connected to the oxygen inlet of the direct liquefaction unit (3) and the fluidized bed gasifier (12). The asphalt outlet of the direct liquefaction unit (3) is connected to the inlet of the asphalt feeding system. The oil outlet of the direct liquefaction unit (3) is connected to the inlet of the hydrogenation stabilization unit (4). The outlet of the hydrogenation stabilization unit (4) is connected to the inlet of the hydrogenation reforming unit (5). The outlet of the hydrogenation reforming unit (5) is connected to the inlet of the light hydrocarbon recovery unit (6). The inlet of the wastewater treatment unit (7) is connected to the wastewater outlets of the direct liquefaction unit (3), the hydrogenation stabilization unit (4), and the hydrogenation reforming unit (5). The hydrogen outlet of the hydrogen production unit (8) is connected to the hydrogen inlet of the direct liquefaction unit (3).

3. The apparatus for coupling direct coal liquefaction with fluidized bed coking and fluidized bed gasification according to claim 2, characterized in that: The asphalt feeding system includes a liquefied asphalt delivery pump (9) and a liquefied asphalt feeding pump (10). The inlet of the liquefied asphalt delivery pump (9) is connected to the asphalt outlet of the direct liquefaction unit (3), the outlet of the liquefied asphalt delivery pump (9) is connected to the inlet of the liquefied asphalt feeding pump (10), and the outlet of the liquefied asphalt feeding pump (10) is connected to the asphalt inlet of the fluidized bed coking furnace (11). The asphalt feeding system is equipped with a heating system throughout the process to stably transport the molten asphalt at 250-350℃ discharged from the direct liquefaction unit (3) to the fluidized bed coking furnace (11).

4. The apparatus for coupling direct coal liquefaction with fluidized bed coking and fluidized bed gasification according to claim 1, characterized in that: The operating temperature of the fluidized bed coking furnace (11) is 400-850℃ and the pressure is 0.05-3.0MPa. The coking system is also equipped with a coking cyclone separator (15) and a dry gas circulation fan (24). The dry gas circulation fan (24) is used to return part of the coking dry gas as a fluidizing medium to the fluidized bed coking furnace (11).

5. The apparatus for coupling direct coal liquefaction with fluidized bed coking and fluidized bed gasification according to claim 4, characterized in that: The gasification system includes a fluidized bed gasifier (12), which operates at a temperature of 900-1250℃ and a pressure of 0.05-3.0MPa. The gasification system is also equipped with a mixing separator (13) and a gasification cyclone separator (14). The high-temperature solid particles of 900-1250℃ separated by the gasification cyclone separator (14) are recycled to the fluidized bed coking furnace (11).

6. The apparatus for coupling direct coal liquefaction with fluidized bed coking and fluidized bed gasification according to claim 5, characterized in that: The tar recovery system includes an oil washing tower (16), a bottom separator of the oil washing tower (16), a washing circulation system, a dry gas cooler (21), and a dry gas separator (22). The gas outlet of the oil washing tower (16) is connected to the inlet of the dry gas cooler (21), the outlet of the dry gas cooler (21) is connected to the inlet of the dry gas separator (22), the bottom oil outlet of the oil washing tower (16) is connected to the inlet of the bottom separator of the oil washing tower (16), the heavy tar outlet of the bottom separator of the oil washing tower (16) is connected to the inlet of the hydrogenation stabilization device (4), the inlet of the washing circulation system is connected to the circulating oil outlet of the bottom separator of the oil washing tower (16), the outlet of the washing circulation system is connected to the washing oil inlet of the oil washing tower (16), the light tar outlet of the dry gas separator (22) is connected to the inlet of the hydrogenation reforming device (5), and the dry gas outlet of the dry gas separator (22) is connected to the inlet of the dry gas circulation fan (24).

7. The apparatus for coupling direct coal liquefaction with fluidized bed coking and fluidized bed gasification according to claim 6, characterized in that: The syngas purification system includes a Venturi scrubber (25), a water scrubbing tower (26), and a black water treatment device (29). The inlet of the Venturi scrubber (25) is connected to the gas outlet of the gasification cyclone separator (14), the outlet of the Venturi scrubber (25) is connected to the inlet of the water scrubbing tower (26), the gas outlet of the water scrubbing tower (26) is connected to the syngas inlet of the hydrogen production unit (8), the bottom black water outlet of the water scrubbing tower (26) is connected to the inlet of the black water treatment device (29), and the outlet of the black water treatment device (29) is connected to the washing water inlet of the water scrubbing tower (26). The syngas purification system is used to wash and cool the crude syngas to a dust content of less than or equal to 10 mg / Nm³.

8. A coupled process method for direct coal liquefaction with fluidized bed coking and fluidized bed gasification, characterized in that: The apparatus based on any one of claims 1 to 7, which couples direct coal liquefaction with fluidized bed coking and fluidized bed gasification, comprises the following steps: S100: Raw coal is hydrogenated and liquefied in a direct liquefaction unit (3) to obtain liquefied oil and molten asphalt at 250-350℃; S200: The molten asphalt is fed into a fluidized bed coking furnace (11) and coking reaction is carried out at 400-850℃ to generate semi-coke and dry distillation gas; S300: The semi-coke is fed into a fluidized bed gasifier (12) and gasified with pure oxygen and superheated steam at 900-1250℃ to generate crude syngas and high-temperature solid particles. S400: Separate the high-temperature solid particles entrained in the crude syngas, and circulate the separated high-temperature solid particles to the fluidized bed coking furnace (11) to provide reaction heat. The separated crude syngas enters the syngas purification system. S500: The dry distillation gas is separated, washed with oil, and cooled by a tar recovery system to obtain heavy tar, light tar, and coking dry gas; S600: The heavy tar and light tar are returned to the coal direct liquefaction system (1) for processing; the purified syngas is sent to the hydrogen production unit (8) to produce hydrogen, which is then supplied back to the direct liquefaction unit (3); the black water generated from syngas washing is treated by the black water treatment unit (29) and then recycled.

9. The exclusive right according to claim 8, characterized in that: In step S200, the material residence time is controlled to be 10-50 seconds by adjusting the circulating dry gas volume, and the mass ratio of circulating semi-coke to asphalt is controlled to be 5-50:

1.

10. The exclusive right according to claim 8, characterized in that: In step S300, the molar ratio of oxygen to carbon is adjusted to 0.4-1.0:1, and the molar ratio of steam to oxygen is controlled to 0.2-2.0:1.

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