Preparation method of high-concentration coal water slurry

Abstract

The invention relates to a preparation method of high-concentration coal water slurry, which comprises the following steps: (1) crushing raw material coal to obtain a material A, and dividing the material A into two parts to obtain a material B and a material C; (2) the material C is subjected to superfine crushing to obtain a material D, the material D is sorted to obtain a material E and a material F, and the particle size of the material E is larger than that of the material F; (3) adding water into the material F to obtain slurry 1, dividing the slurry 1 into two parts, namely slurry 2 and slurry 3, performing fine grinding on the slurry 2 to obtain slurry 4, performing superfine grinding on the slurry 3 to obtain slurry 5, and mixing the slurry 4 and the slurry 5 to obtain mixed slurry; and (4) mixing the material B, the material E, water, an additive and the mixed slurry, and performing coarse grinding to obtain the high-concentration coal water slurry. The pulping energy consumption is reduced, the treatment pressure is shared, the productivity is improved, energy is saved, consumption is reduced, and operation is stable and reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of coal water slurry preparation, in particular to a method for preparing high-concentration coal water slurry. Background Art

[0002] Coal-water slurry is a fluid, pumpable slurry formed by crushing, mixing, grinding, and removing impurities from coal, water, and additives. Currently, most coal-water slurry is used for pressurized coal-water slurry gasification to produce synthesis gas. In a gasifier, coal-water slurry and oxygen undergo complex reactions such as dehydration, combustion, pyrolysis, and gasification to produce synthesis gas containing a mixture of water, carbon monoxide, carbon dioxide, hydrogen, and methane. The carbon monoxide and hydrogen in the synthesis gas are called effective gases. The higher the effective gas content, the higher the coal conversion rate, the lower the carbon dioxide emissions, and the higher the economic and environmental benefits. Therefore, effective measures must be taken to increase the proportion of effective gas in the synthesis gas during the coal gasification process. In the process of water-coal slurry gasification, coal quality, water-coal slurry concentration and oxygen-coal ratio are key factors affecting the effective gas ratio. Among them, coal quality is the inherent characteristic of the raw material, which is generally adapted by adjusting the gasification process parameters. Coal quality is also the main factor affecting the concentration of water-coal slurry. The oxygen-coal ratio needs to be adjusted in time according to the concentration of water-coal slurry. Therefore, the concentration of water-coal slurry is the most important factor affecting the gasification efficiency of water-coal slurry. Some researchers have studied how to prepare high-concentration water-coal slurry.

[0003] CN104987903A discloses a method for preparing gasified coal-water slurry, which comprises pulverizing coal raw materials with different properties, then subjecting them to steps such as grinding, fine grinding, and ultrafine grinding in sections. After mixing them in a specific ratio, the gaps between the coal particles when they are stacked are perfectly filled, improving the stacking efficiency and thus improving the performance of the gasified coal-water slurry. CN105038878A discloses a method for preparing coal-water slurry, which comprises pulverizing dry coal that is difficult to slurry in steps, then subjecting them to steps such as coarse grinding, dehydration, fine grinding, and ultrafine grinding in sections. After mixing them in a specific ratio, the gaps between the coal particles when they are stacked are perfectly filled, improving the stacking efficiency and thus increasing the concentration of the coal-water slurry. CN114456859A discloses a method for preparing a raw material water-coal slurry rich in high-aluminum ash and a method for producing high-aluminum ash, comprising: (1) crushing raw coal and coal gangue to a particle size of ≤6 mm; (2) coarsely grinding the crushed raw coal with water and a dispersant, followed by screening, and returning the oversize with a particle size of ≥300 μm to an upper stage; (3) finely grinding the crushed coal gangue with water and a dispersant, followed by screening, and returning the oversize with a particle size of ≥75 μm to an upper stage; (4) mixing the undersize of the raw coal in step (2) with the undersize of the coal gangue in step (3), and strongly shearing with water and a stabilizer to obtain a finished water-coal slurry. CN109135853A discloses a method for preparing a high-concentration water-coal slurry by fine crushing and less grinding. The method comprises the following steps: (1) fine coal powder, water and additives are mixed and stirred in a mixing and stirring tank to obtain slurry; (2) the slurry is subjected to wet fine grinding to obtain fine slurry A, and the fine slurry A is returned to the mixing and stirring tank to be mixed and stirred with the fine coal powder, the water and the additives to obtain a finished water-coal slurry; a portion of the finished water-coal slurry is diluted with water and then subjected to wet fine grinding to obtain fine slurry B, and the fine slurry B is circulated back to the mixing and stirring tank to perform the mixing and stirring step.

[0004] The technology for preparing high-concentration water-coal slurry mainly includes optimizing coal quality, using high-performance additives, and optimizing coal slurry particle size distribution. Among them, optimizing coal slurry particle size distribution is widely adopted due to its obvious effects and strong operability. At present, the method of optimizing particle size distribution to prepare high-concentration water-coal slurry mainly adds fine grinding and ultrafine grinding steps on the basis of the original coarse particle grinding. The raw materials for preparing fine slurry and ultrafine slurry are finished slurry. There are problems such as high pulping energy consumption, low productivity, limited increase in raw material processing capacity of the production line, and poor energy-saving and environmental protection benefits. Therefore, how to achieve low-energy consumption in the preparation of high-concentration water-coal slurry and optimize the preparation process has become an urgent problem to be solved. Summary of the Invention

[0005] To solve these problems, this technology adds ultra-fine crushing and sorting steps to reduce pulping energy consumption, simplify the grinding steps, improve productivity, and save energy and reduce consumption.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing a high-concentration coal-water slurry, the method comprising the following steps:

[0008] (1) Crushing raw coal to obtain material A, dividing material A into two parts to obtain material B and material C;

[0009] (2) crushing the material C to obtain material D, and sorting the material D to obtain material E and material F, wherein the particle size of the material E is larger than that of the material F;

[0010] (3) adding water to the material F to obtain slurry 1, dividing the slurry 1 into two parts to obtain slurry 2 and slurry 3, finely grinding the slurry 2 to obtain slurry 4, and ultrafine grinding the slurry 3 to obtain slurry 5, and mixing slurries 4 and 5 to obtain a mixed slurry;

[0011] (4) Material B, material E, water, additives and the mixed slurry are mixed and then coarsely ground to obtain the high-concentration water-coal slurry.

[0012] The present invention divides material A into two parts, one for ultrafine crushing and the other for coarse grinding, thereby diverting the material. In combination with sorting material D, material E with a larger particle size is subjected to coarse grinding, and material F with a smaller particle size is subjected to fine grinding and ultrafine grinding after adding water. Through the synergistic effect of the material diversion, sorting and mixed coarse grinding processes, the coal particle size distribution in the water-coal slurry is maintained while simplifying the grinding process, effectively reducing the number of material grindings, avoiding the increased energy consumption caused by the step-by-step grinding in the prior art, and reducing processing energy consumption.

[0013] As a preferred technical solution of the present invention, the particle size of the material A is ≤10 mm.

[0014] As a preferred technical solution of the present invention, the mass ratio of material B to material A is 50%-80%, for example, it can be 50%, 55%, 60%, 65%, 70%, 75% or 80%.

[0015] Preferably, the mass ratio of the material C to the material A is 20%-50%, for example, it can be 20%, 25%, 30%, 35%, 40%, 45% or 50%.

[0016] The present invention optimizes the particle size after preliminary crushing and the material diversion ratio, so that the particle size distribution after mixed coarse grinding in step (3) is reasonable, so as to prepare a high-concentration water-coal slurry with higher concentration and better stability.

[0017] As a preferred technical solution of the present invention, the particle size of the material D is ≤3mm, and the material with a particle size ≤1mm accounts for 30%-90% of the total mass of the material D, for example, it can be 30%, 40%, 50%, 60%, 70%, 80%, and 90%.

[0018] Preferably, the equipment used for the ultrafine crushing is any one of a hammer crusher, a double-roll crusher or a vertical compound crusher.

[0019] In the present invention, the rotor linear speed and crushing ratio of the crushing and ultrafine crushing can be selected and optimized according to the target particle size requirements, and are not further limited here.

[0020] In the present invention, the fine grinding, ultrafine grinding and coarse grinding processes are carried out using conventional grinding equipment in the art, such as a wet ball mill, a tower mill, a rod mill, etc.; grinding conditions such as equipment speed, size and gradation of grinding media, grinding time, etc. can be selected and optimized according to the target particle size requirements and are not further limited here.

[0021] Preferably, the additive includes any one or a combination of at least two of lignin sulfonate, humate and naphthalenesulfonic acid formaldehyde condensate.

[0022] Preferably, the amount of the additive is 0.1-2% of the mass of the raw coal, for example, 0.1%, 0.5%, 1%, 1.5% or 2%.

[0023] As a preferred technical solution of the present invention, it is characterized in that the particle size of the material E is ≥1.0mm-1.5mm, for example, it can be ≥1mm, ≥1.1mm, ≥1.2mm, ≥1.3mm, ≥1.4mm or ≥1.5mm, etc.

[0024] Preferably, the particle size of the material F is less than 1.0 mm-1.5 mm, for example, it may be less than 1.0 mm, less than 1.1 mm, less than 1.2 mm, less than 1.3 mm, less than 1.4 mm or less than 1.5 mm.

[0025] As a preferred technical solution of the present invention, the mass ratio of the material E to the material D is 10%-70%, for example, it can be 10%, 20%, 30%, 40%, 50%, 60% or 70%.

[0026] Preferably, the mass ratio of the material F to the material D is 30%-90%, for example, it can be 30%, 40%, 50%, 60%, 70%, 80% or 90%.

[0027] Preferably, the equipment used for the sorting is any one of a vibrating screen, a wind separator or a probability screen.

[0028] Preferably, the sorting particle size is 1.0 mm to 1.5 mm, for example, it can be 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm or 1.5 mm.

[0029] As a preferred technical solution of the present invention, the mass content of dry materials in the slurry 1 is 30%-50%, for example, it can be 30%, 35%, 40%, 45% or 50%.

[0030] As a preferred technical solution of the present invention, the mass ratio of the slurry 2 to the slurry 3 is (4:6)-(8:2), for example, it can be 4:6, 5:5, 6:4, 7:3 or 8:2.

[0031] As a preferred technical solution of the present invention, the D of the slurry 4 50 It is 20μm-50μm, for example, it can be 20μm, 25μm, 30μm, 35μm, 40μm, 45μm or 50μm, etc.

[0032] Preferably, the D of the slurry 5 50 It is 5μm-25μm, for example, it can be 5μm, 8μm, 10μm, 15μm, 20μm or 25μm.

[0033] Preferably, the amount of water added in step (4) is selected and optimized based on the total water content of the raw coal, the moisture content of the mixed slurry and the target water-coal slurry concentration, and is not further limited here.

[0034] The present invention adds an ultra-fine crushing link, reduces the energy consumption of pulping, shares the processing pressure of the grinding process, sorts the materials after ultra-fine crushing, and uses small-particle coal after crushing for fine grinding instead of finished water-coal slurry ground step by step as the fine grinding raw material. The sorting link can effectively separate coarse particles and fine particles, so that materials with different properties can be processed in a more optimal way, thereby achieving the effect of optimizing process parameters, effectively improving productivity, and saving energy and reducing consumption.

[0035] As a preferred technical solution of the present invention, the mass concentration of the high-concentration coal-water slurry is 64%-68%, for example, it can be 64%, 65%, 66%, 67% or 68%.

[0036] Preferably, the viscosity of the high-concentration coal water slurry is 800 mPa·s-1200 mPa·s, for example, it can be 800 mPa·s, 850 mPa·s, 900 mPa·s, 1000 mPa·s, 1100 mPa·s or 1200 mPa·s.

[0037] Preferably, the particle size of the coal particles in the high-concentration water-coal slurry is ≤2.5 mm.

[0038] Compared with the prior art, the present invention has at least the following beneficial effects:

[0039] (1) The present invention optimizes the preparation process through the synergistic effect of material diversion, sorting and ultra-fine crushing. When achieving the same particle size distribution, the energy utilization rate is higher, the energy saving effect is significant, the output is increased, and the energy consumption per unit product is reduced.

[0040] (2) The water-coal slurry prepared by the present invention has high concentration, moderate viscosity, good stability, and no precipitation or stratification occurs after standing for 3 days. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a process flow chart of the method for preparing high-concentration coal water slurry provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0042] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0043] Example 1

[0044] This embodiment provides a method for preparing a high-concentration coal-water slurry, the method comprising the following steps:

[0045] (1) Crushing raw coal with a total moisture content of 12% to a particle size of ≤10 mm to obtain material A, dividing material A into two parts to obtain material B and material C, wherein the mass ratio of material B to material A is 60%, and the mass ratio of material C to material A is 40%;

[0046] (2) The material C is ultra-finely crushed in a hammer crusher to obtain material D, wherein the particle size of material D is ≤3 mm, and the mass ratio of material ≤1 mm to material D is 30%. Material D is sorted to obtain material E and material F, and the sorting particle size is 1.3 mm, wherein the proportion of material E to material D is 50%, the particle size of material E is ≥1.3 mm, and the particle size of material F is <1.3 mm;

[0047] (3) Add water to the material F, with the ratio of material F to water being 1:1.2, to obtain slurry 1 with a dry material mass ratio of 40%. The slurry 1 is divided into two parts to obtain slurry 2 and slurry 3 with a mass ratio of 5:5, which are respectively finely ground and ultrafinely ground to obtain D 50 40μm slurry 4 and D 50 The slurry 5 is 10 μm, and the slurry 4 and slurry 5 are mixed to obtain a mixed slurry;

[0048] (4) Material B: Material E: Mixed pulp: Water: Sodium lignin sulfonate in a mass ratio of 60:20:44:5.62:0.44 are mixed and coarsely ground until the coal particles have a particle size of ≤2.5 mm to obtain the high-concentration water-coal slurry. The mass concentration of the high-concentration water-coal slurry is 68%, the viscosity is 1155 mPa·s, there is no precipitation and stratification after standing for 3 days, and the energy consumption per unit mass of the product is 20.56 kW / t·h -1 .

[0049] Example 2

[0050] This embodiment provides a method for preparing a high-concentration coal-water slurry, the method comprising the following steps:

[0051] (1) Crushing raw coal with a total moisture content of 18% to a particle size of ≤10 mm to obtain material A, dividing material A into two parts to obtain material B and material C, wherein the mass ratio of material B to material A is 80%, and the mass ratio of material C to material A is 20%;

[0052] (2) The material C is ultra-finely crushed in a hammer crusher to obtain material D, wherein the particle size of material D is ≤3 mm, and the mass ratio of material ≤1 mm to material D is 50%. Material D is sorted to obtain material E and material F, and the sorting particle size is 1.0 mm, wherein the proportion of material E to material D is 50%, the particle size of material E is ≥1.0 mm, and the particle size of material F is <1.0 mm;

[0053] (3) Add water to the material F, with the ratio of material F to water being 1:1.73, to obtain slurry 1 with a dry material mass ratio of 30%. The slurry 1 is divided into two parts to obtain slurry 2 and slurry 3 with a mass ratio of 4:6, which are respectively finely ground and ultrafinely ground to obtain D 50 20μm slurry 4 and D 50 The slurry 5 is 5 μm, and the slurry 4 and slurry 5 are mixed to obtain a mixed slurry;

[0054] (4) Material B: Material E: Mixed pulp: Water: Sodium lignin sulfonate in a mass ratio of 80:10:10.83:27.33:0.082 are mixed and coarsely ground to a particle size of coal particles ≤ 2.5 mm to obtain the high-concentration water-coal slurry. The mass concentration of the high-concentration water-coal slurry is 64%, the viscosity is 978 mPa·s, there is no precipitation and stratification after standing for 3 days, and the energy consumption per unit mass of the product is 22.39 kW / t·h -1 .

[0055] Example 3

[0056] This embodiment provides a method for preparing a high-concentration coal-water slurry, the method comprising the following steps:

[0057] (1) Crushing raw coal with a total moisture content of 15% to a particle size of ≤10 mm to obtain material A, dividing material A into two parts to obtain material B and material C, wherein the mass ratio of material B to material A is 50%, and the mass ratio of material C to material A is 50%;

[0058] (2) The material C is ultra-finely crushed in a hammer crusher to obtain material D, wherein the particle size of material D is ≤3 mm, and the mass ratio of material ≤1 mm to material D is more than 40%. Material D is sorted to obtain material E and material F, and the sorting particle size is 1.5 mm, wherein the proportion of material E to material D is 60%, the particle size of material E is ≥1.5 mm, and the particle size of material F is <1.5 mm;

[0059] (3) Add water to the material F, with the ratio of material F to water being 1:1.25, to obtain slurry 1 with a dry material mass ratio of 40%. The slurry 1 is divided into two parts to obtain slurry 2 and slurry 3 with a mass ratio of 8:2, which are respectively finely ground and ultrafinely ground to obtain D 50 50μm slurry 4 and D 50 The slurry 5 is 25 μm, and the slurry 4 and slurry 5 are mixed to obtain a mixed slurry;

[0060] (4) Material B: Material E: Mixed pulp: Water: Sodium lignin sulfonate in a mass ratio of 50:30:7.16:42.5:1.7 are mixed and coarsely ground to a particle size of coal particles ≤ 2.5 mm to obtain the high-concentration water-coal slurry. The mass concentration of the high-concentration water-coal slurry is 66%, the viscosity is 1055 mPa·s, there is no precipitation and stratification after standing for 3 days, and the energy consumption per unit mass of the product is 19.08 kW / t·h -1 .

[0061] Example 4

[0062] This embodiment provides a method for preparing a high-concentration coal-water slurry. The method is the same as that of Example 1, except that the mass ratio of material B to material A is 40%, the mass ratio of material C to material A is 60%, the ratio of material F to water is 1:1, and no water is added during the coarse grinding in step (4). The prepared high-concentration coal-water slurry has a mass concentration of 68%, a viscosity of 1157 mPa·s, no precipitation or stratification after standing for 3 days, and a yield of 22.58 kW / t·h. -1 .

[0063] Example 5

[0064] This embodiment provides a method for preparing a high-concentration coal-water slurry. The method is the same as that of Example 1, except that the mass ratio of material B to material A is 90%, the mass ratio of material C to material A is 10%, and the water content is adjusted according to actual needs. The prepared high-concentration coal-water slurry has a mass concentration of 68%, a viscosity of 1159 mPa·s, no precipitation or stratification after standing for 1 day, and an energy consumption per unit mass of 20.53 kW / t·h. -1 .

[0065] Example 6

[0066] This embodiment provides a method for preparing a high-concentration coal-water slurry. The method is the same as that of Example 1, except that the mass ratio of slurry 2 to slurry 3 is 3:7. The prepared high-concentration coal-water slurry has a mass concentration of 68%, a viscosity of 1028 mPa·s, and no precipitation or stratification after standing for 3 days. The energy consumption per unit mass of the product is 22.45 kW / t·h. -1 .

[0067] Example 7

[0068] This embodiment provides a method for preparing a high-concentration coal-water slurry. The method is the same as that of Example 1, except that the mass ratio of slurry 2 to slurry 3 is 9:1. The prepared high-concentration coal-water slurry has a mass concentration of 68%, a viscosity of 1148 mPa·s, and no precipitation or stratification after standing for 1.5 days. The energy consumption per unit mass of the product is 20.60 kW / t·h. -1 .

[0069] Comparative Example 1

[0070] This comparative example provides a method for preparing a high-concentration coal-water slurry. The method of Example 1 disclosed in CN104987903A is used for preparation. The obtained high-concentration coal-water slurry has a mass concentration of 66%, a viscosity of 1050 mPa·s, and no precipitation or stratification after standing for 2 days. The energy consumption per unit mass of the product is 23.62 kW / t·h. -1 .

[0071] Comparative Example 2

[0072] This comparative example provides a method for preparing a high-concentration coal-water slurry. Except that material D is not sorted and is directly divided into material E and material F according to a mass ratio of 1:1, the rest is the same as in Example 1. The mass concentration of the obtained high-concentration coal-water slurry is 66%, the viscosity is 1050 mPa·s, there is no precipitation and stratification after standing for 0.5 days, and the energy consumption per unit mass of the product is 23.35 kW / t·h -1 .

[0073] (1) It can be seen from Examples 1 to 3 that the present invention can produce high-concentration water-coal slurry with good stability at low energy consumption by combining material diversion, particle size sorting and ultrafine crushing, and there is no precipitation and stratification after standing for 3 days.

[0074] (2) It can be seen from Examples 1 and 4-7 that the present invention further optimizes the particle size distribution of high-concentration water-coal slurry by the ratio of material diversion, so that the prepared water-coal slurry has better stability and lower unit product energy consumption. When the ratio of material B in the material diversion in Example 4 is too much, the unit product energy consumption is reduced from 20.56 kW / t·h in Example 1 to -1 Increased to 22.58kW / t·h -1 When the proportion of material B in the material diversion in Example 5 is too small, the stability of the water-coal slurry product is reduced and can only be maintained without precipitation and stratification for 1 day. When the mass ratio of slurry 2 and slurry 3 in Example 6 is 3:7, the unit product energy consumption increases to 22.45kW / t·h -1 , when the mass ratio of slurry 2 to slurry 3 in Example 7 was 9:1, the stability of the obtained water-coal slurry product decreased and could only maintain no precipitation and stratification for 1.5 days.

[0075] (3) It can be seen from Example 1 and Comparative Examples 1-2 that the present invention can significantly reduce production energy consumption, optimize particle size distribution, and improve the stability of concentrated water-coal slurry by optimizing the process. The step-by-step grinding process shows higher unit product energy consumption and lower water-coal slurry product stability.

[0076] In summary, the present invention reduces production energy consumption and maintains the stability of high-concentration water-coal slurry through optimized process flow, and can prepare high-concentration water-coal slurry with higher concentration and better stability.

[0077] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for preparing high-concentration coal water slurry, characterized in that: The preparation method comprises the following steps: (1) Crushing raw coal to obtain material A, dividing material A into two parts to obtain material B and material C; (2) crushing the material C to obtain material D, and sorting the material D to obtain material E and material F, wherein the particle size of the material E is larger than that of the material F; (3) adding water to the material F to obtain slurry 1, dividing the slurry 1 into two parts to obtain slurry 2 and slurry 3, finely grinding the slurry 2 to obtain slurry 4, and ultrafine grinding the slurry 3 to obtain slurry 5, and mixing slurries 4 and 5 to obtain a mixed slurry; (4) Material B, material E, water, additives and the mixed slurry are mixed and then coarsely ground to obtain the high-concentration water-coal slurry.

2. The preparation method according to claim 1, characterized in that The particle size of the material A is ≤10 mm.

3. The preparation method according to claim 1 or 2, characterized in that The mass ratio of material B to material A is 50%-80%; Preferably, the mass ratio of the material C to the material A is 20%-50%.

4. The preparation method according to any one of claims 1 to 3, characterized in that The particle size of the material D is ≤3 mm, and the material with a particle size ≤1 mm accounts for 30%-90% of the total mass of the material D.

5. The preparation method according to any one of claims 1 to 4, characterized in that The particle size of the material E is ≥1.0mm-1.5mm; Preferably, the particle size of the material F is less than 1.0 mm-1.5 mm.

6. The preparation method according to any one of claims 1 to 5, characterized in that The mass ratio of the material E to the material D is 10%-70%; Preferably, the mass ratio of the material F to the material D is 30%-90%; Preferably, the sorting particle size is 1.0 mm to 1.5 mm.

7. The preparation method according to any one of claims 1 to 6, characterized in that The mass content of dry materials in the slurry 1 is 30%-50%.

8. The preparation method according to any one of claims 1 to 7, characterized in that The mass ratio of the slurry 2 to the slurry 3 is (4:6)-(8:2).

9. The preparation method according to any one of claims 1 to 8, characterized in that The D of the slurry 4 50 20μm-50μm; Preferably, the D of the slurry 5 50 5μm-25μm.

10. The preparation method according to any one of claims 1 to 9, characterized in that: The mass concentration of the high-concentration coal-water slurry is 64%-68%; Preferably, the viscosity of the high-concentration coal-water slurry is 800 mPa·s-1200 mPa·s; Preferably, the particle size of the coal particles in the high-concentration water-coal slurry is ≤2.5 mm.

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