CN115093889A

CN115093889A - Grading, quality-separating and comprehensive conversion method for low-rank coal

Info

Publication number: CN115093889A
Application number: CN202210925896.9A
Authority: CN
Inventors: 王武生; 黄勇; 郝婷; 王忠臣; 魏江涛; 刘丹; 折喆; 刘彪
Original assignee: Shaanxi Yanchang Petroleum Group Co Ltd
Current assignee: Shaanxi Yanchang Petroleum Group Co Ltd
Priority date: 2022-08-03
Filing date: 2022-08-03
Publication date: 2022-09-23
Anticipated expiration: 2042-08-03
Also published as: CN115093889B

Abstract

The invention discloses a low-rank coal grading and quality-grading comprehensive conversion method, which comprises the steps of sorting raw material coal into coarse-faced coal, medium-faced coal and fine-faced coal according to particle sizes; after the coarse coal is converted by the pyrolysis and gasification integrated reaction unit, a small amount of byproduct oil sludge is returned to the pyrolysis; the byproduct heavy tar is mixed with the medium coal, the external heavy oil and the catalyst to form coal oil slurry, and then the coal oil slurry is subjected to hydrogenation conversion through a multiphase flow reaction unit and an oil upgrading unit in sequence; mixing the byproduct coarse ash, fine ash and phenol-containing wastewater with fine coal and supplemented raw material coal to obtain coke slurry, and feeding the coke slurry into a coke slurry gasification unit for deep conversion; the byproduct synthesis gas is subjected to partial hydrogen extraction and then is converted into hydrogen for the coal oil slurry, and the high hydrocarbon-containing mixed gas obtained through the hydrocarbon removal and the byproduct noncondensable gas of the oil upgrading unit are used as fuel for the upstream pulverized coal drying process; taking the byproduct residue in the conversion process of the coal oil slurry as a raw material for pyrolysis; the method realizes the high-quality resource utilization of three wastes in the low-rank coal conversion process, and has obvious economic and environmental benefits.

Description

Low-rank coal grading and quality-grading comprehensive conversion method

Technical Field

The invention relates to a low-rank coal utilization technology, in particular to a low-rank coal grading and quality-grading comprehensive conversion method.

Background

The reserves of the low-rank coal in China are very rich, the quality-based conversion of the low-rank coal is beneficial to improving the comprehensive energy conversion efficiency of the process engineering, and the method is an important method for high-efficiency clean utilization of the coal. Wherein, the pyrolysis or direct liquefaction of low-rank coal is an important technical component of quality-based conversion.

Compared with lump coal or seed coal pyrolysis technology, the yield of coal tar products can be greatly improved by fast pyrolysis of pulverized coal, and in addition, the proportion of small particle products in raw coal is increased along with the continuous improvement of the coverage rate of mechanized coal mining technology, so that the fast pyrolysis technology of pulverized coal has great competitiveness. In particular to a fluidized bed pulverized coal pyrolysis and gasification integrated technology, which takes the heat semi-coke produced by the rapid pyrolysis of pulverized coal in a pyrolysis section as a carbon source of a gasification section of a circulating fluidized bed, takes high-temperature synthesis gas produced by the gasification section as a heat source in the pyrolysis process of the pyrolysis section and as a hydrogen source of a pyrolysis stabilizer, and realizes the coupling of materials and heat between two different reaction areas.

However, the fluidized bed pulverized coal pyrolysis and gasification integrated technology has a relatively strict requirement on the particle size distribution range of the raw material pulverized coal. The high proportion of the fine powder can cause that the productive fine coke powder is difficult to stay in the reactor to cause carbon deficiency in a gasification section, and the fine powder is moved to a purification system and mixed with the produced liquid coal tar, so that a large amount of tar products are absorbed and taken away to cause the yield of the tar in the device to be reduced; the high coarse powder proportion can increase the difficulty of the pneumatic conveying process during the feeding period, reduce the tar yield, and easily cause abnormal powder fluidization in the gasification section and cause bed layer sintering scars or caking, thus causing the production accident that the device is forced to stop.

Some steam added in the gasification process of the fluidized bed can not be cracked, and pyrolysis water of a byproduct of pulverized coal pyrolysis enters a gas purification system, a large amount of phenol-containing wastewater can be generated, and the part of wastewater treatment cost is high, so that the method is a key symptom for restricting the rapid development of the pyrolysis industry. Another symptom of the fluidized bed pulverized coal pyrolysis and gasification integrated technology is that the bed gasification temperature is limited by the melting point of the coal ash and cannot be increased, so that the carbon content in the coarse ash and the fine ash is high, and the resource utilization is insufficient.

The bed temperature of the direct coal liquefaction or oil-coal co-hydroconversion technology is lower than the bed temperature of the pulverized coal fast pyrolysis, the reaction depth is not enough in the process, the oil content of a large amount of solid residues is high, and the residues are mainly used in a low-value mode through combustion and the like at present. In addition, due to the limitation of cyclone dust removal efficiency in the pulverized coal pyrolysis process, partial oil sludge is inevitably produced in a gas purification system, and the oil sludge can not be used with high value at present.

Therefore, aiming at various defects in the grading and quality-grading conversion process of the existing low-rank coal, the development of a grading and quality-grading high-efficiency comprehensive conversion method of the low-rank coal, which can realize the absorption of intermediate byproducts in a system, the complementation of heat supply of materials in the system and the resource recycling of wastes, is urgently needed.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a low-rank coal grading and quality-grading comprehensive conversion method, so that the resource high-quality utilization of byproduct waste in the low-rank coal conversion process is realized, and the economic and environmental benefits are improved.

In order to achieve the purpose, the invention adopts the following technical scheme:

a low-rank coal grading and quality-separating comprehensive conversion method comprises the following steps:

1) part of raw material coal is sent into a pulverized coal grading preparation unit, and under the drying, conveying and screening effects of non-condensable mixed gas, non-condensable combustible gas and flue gas generated by air combustion, pulverized coal ground by the unit is divided into three raw materials, namely medium-surface coal, coarse-surface coal and fine-surface coal;

2) granulating and molding one part of the coarse coal, the residues and the oil sludge in a granulating unit to obtain powder particles, sending the powder particles and the other part of the coarse coal into a pyrolysis and gasification integrated reaction unit, and carrying out chemical reaction on the unit, steam and oxygen to produce dust-containing oil-containing coarse gas and coarse ash;

3) after the dust-containing and oil-containing crude gas is sent into a cyclone dust removal unit, the dusted crude gas and fine coke powder are produced, wherein the dusted crude gas is directly introduced into a purification and multiphase separation unit to produce medium and light tar, the dedusted and oil-removed gas, heavy tar, oil sludge, mixed phenol and phenol-containing wastewater;

4) introducing the coal gas subjected to dust removal and oil removal into a gas primary separation unit, and separating by the unit to produce hydrogen, uncondensed combustible gas and purified coal gas; introducing the obtained purified coal gas and the crude synthesis gas into a gas conversion and purification unit, and converting to produce mixed synthesis gas;

5) the catalyst, heavy oil, medium coal and heavy tar are mixed in the coal oil slurry preparation unit and then output coal oil slurry, and the coal oil slurry and hydrogen chemically react in the multiphase flow reaction unit to produce residues and intermediate oil products; introducing the obtained intermediate oil product, medium light tar and hydrogen into an oil product upgrading unit together for conversion to produce noncondensable mixed gas, gasoline, diesel oil and bunker fuel oil;

6) mixing part of raw material coal, fine-flour coal, coarse ash, fine coke powder and phenol-containing wastewater in a coke coal slurry preparation unit and outputting coke coal slurry; the obtained coke slurry and oxygen are subjected to chemical reaction in a coke slurry gasification unit to produce crude synthesis gas and gasification ash.

Furthermore, the content of volatile components of an air drying base in industrial analysis data of the raw material coal is not less than 28%, and the softening temperature of coal ash corresponding to the coal is not lower than 1200 ℃ measured according to the national standard GB 219-74.

Furthermore, the moisture content of the medium-sized coal, the coarse-sized coal and the fine-sized coal is not higher than 4%, the mass proportion of the powder with the particle size of less than 60 mu m or more than 600 mu m in the coarse-sized coal is not more than 4%, the mass proportion of the powder with the particle size of more than 60 mu m in the fine-sized coal is not more than 4%, and the mass proportion of the powder with the particle size of less than 15 mu m or more than 400 mu m in the medium-sized coal is not more than 4%.

Furthermore, the mass fraction of solid in the powder and granular material after the residue, the coarse coal and the oil sludge are mixed, granulated and molded is not less than 85 percent, the mass proportion of the powder and granular material with the particle size of less than 60 mu m or more than 600 mu m is not more than 7 percent, and the mass proportion of the powder and granular material with the particle size of more than 1000 mu m is not more than 2 percent.

Further, a pyrolysis region and a gasification region in the pyrolysis and gasification integrated reaction unit both carry out a fluidization reaction process of gas-solid two-phase flow, semicoke produced in the pyrolysis region flows into the gasification region to be used as a gasification raw material, and high-temperature synthesis gas produced in the gasification region flows into the pyrolysis region to be used as a reaction heat source; during normal operation, the reaction temperature of the pyrolysis zone and the reaction temperature of the gasification zone are respectively controlled within the ranges of 5005660 ℃ and 85051100 ℃, and the reaction pressure is controlled within the range of 0.657.8 MPaG.

Furthermore, the steam and the oxygen are mixed and then are introduced into the pyrolysis and gasification integrated reaction unit, and the molecular number ratio of the steam to the oxygen is controlled within the range of (1.555):1 during normal operation.

Further, the initial boiling point of the heavy tar is not lower than 390 ℃, the mass percentage of tetrahydrofuran insoluble substances in the oil sludge is not lower than 44%, and the volume percentage of hydrocarbon compounds in the non-condensable combustible gas is not lower than 75%.

Further, the catalyst is a solid powdery mixture, the mass ratio of internal moisture is not higher than 1.5%, and the feeding mass of the catalyst is not higher than 2% of that of the medium-sized coal.

Further, the heavy oil is heavy oil of a refinery or heavy coal tar, and the initial boiling point of the heavy oil is not lower than 390 ℃; the mass ratio of tetrahydrofuran insoluble substances in the residue is not less than 46%; the mass ratio of the solid phase in the coking coal slurry is in the range of 57 percent 567 percent.

Further, the multiphase flow reaction unit comprises 155 hydrogenation reactors in multiphase flow state, during normal operation, the reaction temperature is in the range of 3705485 ℃, and the reaction pressure is in the range of 15523 MPaG; the oil upgrading unit comprises 153 fixed bed catalytic hydrogenation reactors, and during normal operation, the reaction temperature is in the range of 3855465 ℃ and the reaction pressure is in the range of 11518 MPaG; the coke coal slurry gasification unit comprises 255 entrained flow wet gasification reactors, and during normal operation, the reaction temperature is in the range of 120051450 ℃ and the reaction pressure is in the range of 657.8 MPaG.

Compared with the prior art, the invention has the following beneficial effects:

firstly, the invention carries out classification and sorting on the coal powder produced by the raw coal preparation unit according to the granularity, and takes the coal powder with different granularities as the raw material of different downstream deep processing devices. The grading, sorting and utilizing process effectively reduces the energy consumption in the process of preparing the pulverized coal while fully improving the processing efficiency of each deep processing device at the downstream. Particularly, the concentration of the coke slurry is improved while the oil mass of the oil sludge of a downstream system of the pyrolysis gasification device is obviously reduced, and the abrasion and the blockage of large-particle coal powder to key equipment in the oil-coal slurry processing process are effectively inhibited.

Secondly, the fluidized bed pulverized coal pyrolysis and gasification integrated unit is selected as a key processing link, and the unit realizes the efficient coupling of materials and heat in two reaction processes of pulverized coal pyrolysis and generated semicoke gasification. Meanwhile, the byproduct residues in the oil sludge and oil coal slurry processing process of the downstream system of the pyrolysis gasification device are efficiently consumed, and the high-quality utilization of two intermediate byproducts is realized.

Thirdly, the phenolic wastewater in a downstream system of the pyrolysis gasification device is fully utilized to have good positive effect on the slurry forming performance of the water coke coal slurry, the phenolic wastewater is used for preparing the slurry, the cost of water treatment is greatly reduced, meanwhile, the stability of the water coke coal slurry is improved, in addition, fine coal serving as a key component of graded slurry forming can obviously improve the solid phase concentration of the water coke coal slurry, and meanwhile, raw materials which are not suitable for the treatment of the pyrolysis gasification device can be reasonably utilized in a graded manner.

Fourthly, the coarse ash and the fine ash discharged by the pyrolysis and gasification integrated reaction unit are used as raw materials of the coke slurry, so that the resource utilization of the high-carbon-content waste is realized. Due to the limitation of the melting point of the fly ash, the highest gasification temperature of the fluidized bed is controlled to be far lower than the gasification temperature of the entrained flow bed, so that the conversion rate of semicoke in the bed layer is limited, the carbon content of coarse ash discharged from the inside and the outside of the bed layer is higher, and the carbon content of fine ash collected by the cyclone dust removal unit is higher, so that the deep conversion of two wastes is realized when the cyclone dust removal unit is used for pulping.

Fifthly, the invention takes the non-condensable gas by-produced by the system at the downstream of the pyrolysis gasification device and the non-condensable gas by-produced by the system at the downstream of the oil-coal slurry conversion device as the fuel gas in the drying process of the pulverized coal grading preparation unit, thereby realizing the resource utilization of part of the by-products in the process of the graded and graded conversion of the pulverized coal.

Sixth, the synthesis gas from different devices is mixed and then subjected to shift reaction conversion, so that water molecule complementation is realized, and the steam injection amount in the system in the shift reaction process is remarkably reduced. The synthesis gas from the pyrolysis and gasification integrated reaction unit is subjected to dust removal, oil washing, water washing, hydrocarbon removal and partial hydrogen extraction to form dry gas almost without water molecules, while the synthesis gas from the coke slurry gasification unit is subjected to water washing to be in a water vapor saturated state at 2505400 ℃, and the former is slightly heated and then mixed with the latter to obtain the downstream shift reaction raw material gas higher than the dew point. Effectively avoids the damage of the shift reaction catalyst caused by the easy water carrying of saturated gas, and simultaneously avoids the steam addition into dry gas so as to reduce the water consumption of the system.

Drawings

FIG. 1 is a schematic structural diagram of an embodiment of the present invention;

wherein: a. a coal oil slurry preparation unit; b. a multiphase flow reaction unit; c. an oil upgrading unit; d. a pulverized coal grading preparation unit; e. a granulation unit; f. a pyrolysis and gasification integrated reaction unit; g. a cyclone dust removal unit; h. a purification and multi-phase separation unit; i. a gas primary separation unit; j. a gas shift and purification unit; k. a coke slurry preparation unit; m, a coking coal slurry gasification unit;

1. a catalyst; 2. heavy oil; 3. coal oil slurry; 4. residue; 5. an intermediate oil product; 6. the mixed gas is not condensed; 7. gasoline; 8. diesel oil; 9. bunker fuel oil; 10. air; 11. raw material coal; 12. steam; 13. medium-sized coal; 14. coarse coal; 15. fine coal; 16. coke breeze particles; 17. crude gas containing dust and oil; 18. coarse ash; 19. after dust fall, coarse coal gas; 20. fine coke powder; 21. medium and light tar; 22. removing dust and oil of the coal gas; 23. heavy tar; 24. oil sludge; 25. hydrogen gas; 26. non-condensable combustible gas; 27. purifying the coal gas; 28. mixing the synthesis gas; 29. mixing phenol; 30. oxygen gas; 31. phenol-containing wastewater; 32. a coke coal slurry; 33. coarse synthesis gas; 34. gasifying the ash.

Detailed description of the preferred embodiment

The invention is further illustrated by the following specific examples.

As shown in fig. 1, a low-rank coal grading and quality-grading comprehensive conversion method comprises the following steps:

1) part of the raw material coal 11 is sent into a pulverized coal grading preparation unit d, and under the drying, conveying and screening effects of flue gas generated by combustion of the non-condensable gas mixture 6, the non-condensable combustible gas 26 and the air 10, the pulverized coal ground by the unit is divided into three raw materials, namely medium-surface coal 13, coarse-surface coal 14 and fine-surface coal 15;

2) after a part of the coarse surface coal 14, the residue 4 and the sludge 24 are granulated and formed in a granulation unit e, the granulated and formed part of the coarse surface coal and the other part of the coarse surface coal 14 are sent to a pyrolysis and gasification integrated reaction unit f, and after the unit is chemically reacted with steam 12 and oxygen 30, dust-containing oil-containing raw gas 17 and raw ash 18 are produced;

3) after the dust-containing and oil-containing crude gas 17 is sent into a cyclone dust removal unit g, producing dusty crude gas 19 and fine coke powder 20, wherein the dusty crude gas 19 is directly introduced into a purification and multiphase separation unit h to produce medium and light tar 21, dust-removing and oil-removing crude gas 22, heavy tar 23, oil sludge 24, mixed phenol 29 and phenol-containing wastewater 31;

4) the coal gas 22 after dust and oil removal is introduced into a gas primary separation unit i, and hydrogen 25, noncondensable combustible gas 26 and purified coal gas 27 are produced after the separation by the unit. The obtained purified coal gas 27 and the crude synthesis gas 33 are introduced into a gas conversion and purification unit j together, and a mixed synthesis gas 28 is produced after conversion;

5) the catalyst 1, the heavy oil 2, the medium coal 13 and the heavy tar 23 are mixed in the coal oil slurry preparation unit a and then output the coal oil slurry 3, and the coal oil slurry and the hydrogen 25 are chemically reacted in the multiphase flow reaction unit b to produce the residue 4 and the intermediate oil 5. Introducing the obtained intermediate oil product 5, medium and light tar 21 and hydrogen 25 into an oil product upgrading unit c for conversion to produce noncondensable mixed gas 6, gasoline 7, diesel oil 8 and bunker fuel oil 9;

6) part of the raw material coal 11, the fine coal 15, the coarse ash 18, the fine coke powder 20 and the phenol-containing wastewater 31 are mixed in a coke slurry preparation unit k and then coke slurry 32 is output. The obtained coke slurry 32 and oxygen 30 are subjected to chemical reaction in a coke slurry gasification unit m to produce crude synthesis gas 33 and gasification ash 34.

The content of air drying base volatile components in the industrial analysis data of the raw material coal 11 is not less than 28%, and the softening temperature of coal ash corresponding to the coal is not less than 1200 ℃ measured according to GB 219-74.

The moisture content of the medium-sized coal 13, the coarse-sized coal 14 and the fine-sized coal 15 is not higher than 4%, the mass ratio of the powder with the particle size of less than 60 mu m or more than 600 mu m in the coarse-sized coal 14 is not higher than 4%, the mass ratio of the powder with the particle size of more than 60 mu m in the fine-sized coal 15 is not higher than 4%, and the mass ratio of the powder with the particle size of less than 15 mu m or more than 400 mu m in the medium-sized coal 13 is not higher than 4%.

The coking coal powder particles 16 are powder particles formed by mixing, granulating and molding the residue 4, the coarse-face coal 14 and the oil sludge 24, the mass fraction of solids in the powder particles is not less than 85%, the mass ratio of the powder particles with the particle size of less than 60 mu m or more than 600 mu m in the powder particles is not more than 7%, and the mass ratio of the powder particles with the particle size of more than 1000 mu m is not more than 2%.

The pyrolysis region and the gasification region in the pyrolysis and gasification integrated reaction unit f both carry out fluidization reaction process of gas-solid two-phase flow, and the semicoke produced in the pyrolysis region flows into the gasification region as gasification raw material and the high-temperature synthesis gas produced in the gasification region flows into the pyrolysis region as reaction heat source. During normal operation, the reaction temperature of the pyrolysis zone and the reaction temperature of the gasification zone are respectively controlled within the ranges of 5005660 ℃ and 85051100 ℃, and the reaction pressure is controlled within the range of 0.657.8 MPaG.

The steam 12 and the oxygen 30 need to be mixed and then are introduced into the pyrolysis gasification integrated reaction unit f, and the molecular number ratio of the steam to the oxygen is controlled within the range of 1.5:155:1 during normal operation.

The initial boiling point of the heavy tar 23 is not lower than 390 ℃, the mass ratio of tetrahydrofuran insoluble substances in the oil sludge 24 is not lower than 44%, and the volume ratio of hydrocarbon compounds in the non-condensable combustible gas 26 is not lower than 75%.

The catalyst 1 is a solid powdery mixture, the mass percentage of internal moisture is not higher than 1.5%, and the feeding mass of the catalyst is not higher than 2% of that of the medium-sized coal 13.

The heavy oil 2 can be selected from heavy oil of a refinery or heavy coal tar, and the initial boiling point of the heavy oil 2 is not lower than 390 ℃.

The mass ratio of tetrahydrofuran insoluble matter in the residue 4 is not less than 46%.

The multiphase flow reaction unit b comprises 155 multiphase flow state hydrogenation reactors, and during normal operation, the reaction temperature is in the range of 3705485 ℃, and the reaction pressure is in the range of 15523 MPaG.

The oil upgrading unit c comprises 153 fixed bed catalytic hydrogenation reactors, and during normal operation, the reaction temperature is 3855465 ℃ and the reaction pressure is 11518 MPaG.

The mass ratio of the solid phase in the coke coal slurry 32 is 57 percent and 567 percent.

The coking coal slurry gasification unit m comprises 255 entrained-flow wet gasification reactors, and during normal operation, the reaction temperature is in the range of 120051450 ℃ and the reaction pressure is in the range of 657.8 MPaG.

The above-described embodiments are provided to better explain the principles of the present invention and not to limit the present invention by any means, such as by making modifications, equivalents, and improvements within the spirit and scope of the present invention as defined by the appended claims.

Claims

1. A low-rank coal grading and quality-grading comprehensive conversion method is characterized by comprising the following steps:

1) part of the raw material coal (11) is sent into a pulverized coal grading preparation unit (d), and under the drying, conveying and screening effects of flue gas generated by combustion of non-condensable gas (6), non-condensable combustible gas (26) and air (10), the pulverized coal ground by the unit is divided into three raw materials, namely medium-surface coal (13), coarse-surface coal (14) and fine-surface coal (15);

2) granulating and molding one part of the coarse surface coal (14), the residue (4) and the oil sludge (24) in a granulating unit (e) to obtain powder particles, sending the powder particles and the other part of the coarse surface coal (14) into a pyrolysis and gasification integrated reaction unit (f), and carrying out chemical reaction on the powder particles, steam (12) and oxygen (30) in the pyrolysis and gasification integrated reaction unit to produce dust-containing oil-containing coarse gas (17) and coarse ash (18);

3) after the dust-containing and oil-containing crude gas (17) is sent into a cyclone dust removal unit (g), the dusted crude gas (19) and fine coke powder (20) are produced, wherein the dusted crude gas (19) is directly introduced into a purification and multiphase separation unit (h), and medium and light tar (21), dust-removing and oil-removing coal gas (22), heavy tar (23), oil sludge (24), mixed phenol (29) and phenol-containing wastewater (31) are produced;

4) introducing the dedusted and deoiled coal gas (22) into a gas primary separation unit (i), and separating by the unit to produce hydrogen (25), uncondensed combustible gas (26) and purified coal gas (27); the obtained purified coal gas (27) and the raw synthesis gas (33) are introduced into a gas conversion and purification unit (j) together, and a mixed synthesis gas (28) is produced after conversion;

5) mixing the catalyst (1), the heavy oil (2), the medium coal (13) and the heavy tar (23) in an oil-coal slurry preparation unit (a), outputting an oil-coal slurry (3), and chemically reacting with hydrogen (25) in a multiphase flow reaction unit (b) to produce a residue (4) and a medium oil product (5); introducing the obtained intermediate oil (5), medium and light tar (21) and hydrogen (25) into an oil upgrading unit (c) for conversion to produce noncondensable mixed gas (6), gasoline (7), diesel oil (8) and bunker fuel oil (9);

6) mixing part of raw material coal (11), fine surface coal (15), coarse ash (18), fine coke powder (20) and phenol-containing wastewater (31) in a coke slurry preparation unit (k) and outputting coke slurry (32); the obtained coke slurry (32) and oxygen (30) are subjected to chemical reaction in a coke slurry gasification unit (m) to produce crude synthesis gas (33) and gasification ash (34).

2. The low-rank coal grading and quality-grading comprehensive conversion method according to claim 1, characterized in that: the content of volatile components of an air drying base in industrial analysis data of the raw material coal (11) is not less than 28%, and the softening temperature of coal ash corresponding to the coal is not lower than 1200 ℃ measured according to the national standard GB 219-74.

3. The low-rank coal grading and quality-grading comprehensive conversion method according to claim 1, characterized in that: the moisture content of the medium-sized coal (13), the moisture content of the coarse-sized coal (14) and the moisture content of the fine-sized coal (15) are not higher than 4%, the mass percentage of powder with the particle size of less than 60 mu m or more than 600 mu m in the coarse-sized coal (14) is not more than 4%, the mass percentage of powder with the particle size of more than 60 mu m in the fine-sized coal (15) is not more than 4%, and the mass percentage of powder with the particle size of less than 15 mu m or more than 400 mu m in the medium-sized coal (13) is not more than 4%.

4. The low-rank coal grading and quality-grading comprehensive conversion method according to claim 1, characterized in that: the mass fraction of solid in the powder and granular material formed by mixing, granulating and molding the residue (4), the coarse coal (14) and the oil sludge (24) is not less than 85 percent, the mass ratio of the powder and granular material with the particle size of less than 60 mu m or more than 600 mu m is not more than 7 percent, and the mass ratio of the powder and granular material with the particle size of more than 1000 mu m is not more than 2 percent.

5. The low-rank coal grading and quality-grading comprehensive conversion method according to claim 1, characterized in that: the pyrolysis region and the gasification region in the pyrolysis and gasification integrated reaction unit (f) both carry out a fluidization reaction process of gas-solid two-phase flow, semicoke produced in the pyrolysis region flows into the gasification region to be used as a gasification raw material, and high-temperature synthesis gas produced in the gasification region flows into the pyrolysis region to be used as a reaction heat source; during normal operation, the reaction temperature of the pyrolysis zone and the reaction temperature of the gasification zone are respectively controlled within the ranges of 5005660 ℃ and 85051100 ℃, and the reaction pressure is controlled within the range of 0.657.8 MPaG.

6. The low-rank coal grading and quality-grading comprehensive conversion method according to claim 1, characterized in that: the steam (12) and the oxygen (30) need to be mixed and then are introduced into the pyrolysis and gasification integrated reaction unit (f), and the molecular number ratio of the steam to the oxygen is controlled within the range of (1.555):1 during normal operation.

7. The low-rank coal grading and quality-grading comprehensive conversion method according to claim 1, characterized in that: the initial boiling point of the heavy tar (23) is not lower than 390 ℃, the mass proportion of tetrahydrofuran insoluble substances in the oil sludge (24) is not lower than 44%, and the volume proportion of hydrocarbon compounds in the non-condensable combustible gas (26) is not lower than 75%.

8. The low-rank coal grading and quality-grading comprehensive conversion method according to claim 1, characterized in that: the catalyst (1) is a solid powdery mixture, the mass ratio of internal moisture is not higher than 1.5%, and the feeding mass of the catalyst is not higher than 2% of that of the medium-sized coal (13).

9. The low-rank coal grading and quality-grading comprehensive conversion method according to claim 1, characterized in that: the heavy oil (2) is heavy oil of a refinery or heavy coal tar, and the initial boiling point of the heavy oil (2) is not lower than 390 ℃; the mass ratio of tetrahydrofuran insoluble substances in the residue (4) is not less than 46%; the mass ratio of the solid phase in the coke coal slurry (32) is 57 percent and 567 percent.

10. The low-rank coal grading and quality-grading comprehensive conversion method according to claim 1, characterized in that: the multiphase flow reaction unit (b) comprises 155 hydrogenation reactors in multiphase flow state, during normal operation, the reaction temperature is in the range of 3705485 ℃, and the reaction pressure is in the range of 15523 MPaG; 153 fixed bed catalytic hydrogenation reactors are contained in the oil upgrading unit (c), during normal operation, the reaction temperature is 3855465 ℃, and the reaction pressure is 11518 MPaG; the coking coal slurry gasification unit (m) comprises 255 entrained flow wet gasification reactors, and during normal operation, the reaction temperature is in the range of 120051450 ℃ and the reaction pressure is in the range of 657.8 MPaG.