CN110699131B - Preparation method of blended coal-water coal slurry - Google Patents

Abstract

The invention provides a preparation method of blended coal-water slurry, which comprises the following steps: mixing and crushing raw material coal, petroleum coke and fly ash to obtain first slurry; mixing petroleum coke, fly ash, water and an additive to obtain a second slurry; mixing and stirring the first slurry and the second slurry to obtain a third slurry, then shaping and finely grinding to obtain a fourth slurry, and screening the fourth slurry to obtain a fifth slurry and a sixth slurry as a screen residue; returning part of the sixth slurry to be mixed with the second slurry, and returning the rest sixth slurry to be shaped and finely ground; and outputting the fifth slurry to obtain the coal water slurry. The method adopts a coal blending technology, petroleum coke and fly ash are added on the basis of raw material coal to form blended coal, the blended coal improves the slurry forming performance of coal types and the concentration of the coal water slurry, and the stacking efficiency of the coal water slurry can be improved by matching the granularity among coal components, so that the heat value of the coal water slurry is improved, and the coal water slurry can be better used as gasified coal water slurry.

Description

Preparation method of blended coal-water coal slurry

Technical Field

The invention belongs to the technical field of coal chemical industry, and relates to a preparation method of blended coal-water slurry.

Background

The coal water slurry is a novel coal-based fluid fuel, is a clean fuel capable of replacing heavy oil and coal, and has the advantages of high concentration, fine granularity, high combustion efficiency and the like, and is widely applied. Coal gasification is an important basic process of coal chemical industry, the gasification of coal water slurry is also a research focus, the concentration of the coal water slurry directly determines the energy consumption index of the gasification process, and the preparation of the high-concentration coal water slurry is important for key parameters such as high gasification efficiency, low specific coal consumption, low specific oxygen consumption and the like.

The preparation of high-concentration coal water slurry is a difficult problem in the field of coal water slurry, especially for coal types which are difficult to form slurry, low-rank coal is a coal type which is generally recognized to have poor pulping performance, the water content and ash content are high, the oxygen element content is high, the grindability is poor, the heat value is low, the concentration of the prepared coal slurry is low, and the application requirement cannot be met in the gasification field. CN101173765A discloses a method for preparing coal water slurry by using low-rank coal, which comprises the steps of mixing the crushed low-rank coal with water in proportion, then carrying out wet coarse grinding, mixing part of the coal slurry subjected to wet coarse grinding with the water, carrying out wet fine grinding, then feeding the other part of the coal slurry into a filtering device, and then carrying out high-speed stirring, standing or low-speed stirring to obtain a coal water slurry product; however, the low-rank raw material coal used by the method has high water content, the required operation is more complicated, and the concentration of the obtained water-coal-slurry product is limited.

CN 105038878A discloses a method for preparing coal water slurry, which comprises the steps of crushing low-rank coal, performing coarse grinding, dehydration, fine grinding, superfine grinding and the like in parts, kneading and strong shearing treatment to obtain the coal water slurry product.

In order to improve the concentration and gasification performance of a coal water slurry product, cost is increased by changing or improving raw materials, so that the concentration of the coal water slurry can be increased by other ways, such as a coal blending technology which is applied at present but has little relation in the field of preparation of the coal water slurry, and no clear description is provided for selection of which materials are adopted to have better blending effect with coal and blending proportion.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a preparation method of coal water slurry mixed with coal, which adopts a coal mixing technology and utilizes petroleum coke and fly ash to improve the slurry forming performance of raw material coal, thereby improving the concentration and the accumulation efficiency of the coal water slurry, ensuring that the obtained coal water slurry has high gasification efficiency and reducing the cost of required raw materials.

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

the invention provides a preparation method of blended coal-water slurry, which comprises the following steps:

(1) mixing and crushing raw material coal, petroleum coke and fly ash to obtain first slurry; mixing petroleum coke, fly ash, water and an additive to obtain a second slurry;

(2) mixing and stirring the first slurry and the second slurry obtained in the step (1) to obtain a third slurry, and then shaping and fine grinding the third slurry to obtain a fourth slurry;

(3) screening the fourth slurry obtained in the step (2), wherein the screened slurry is a fifth slurry, and the screen residue is a sixth slurry;

(4) returning part of the sixth slurry obtained in the step (3) to the step (1) to be mixed with the second slurry, and returning the rest of the sixth slurry to the step (2) to carry out shaping and fine grinding; and (4) outputting the fifth slurry obtained in the step (3) to obtain the coal water slurry.

In the invention, by adopting a coal blending technology, petroleum coke and fly ash are added on the basis of raw material coal to form blended coal, and then the coal water slurry is prepared by the processing steps of mixing, shaping, fine grinding, screening and the like; the blended coal can reduce the ash content of the coal water slurry and improve the slurrying performance of the raw material coal, so that the concentration of the coal water slurry is improved, and the combination of the particle sizes of different components can improve the stacking efficiency of the coal water slurry and reduce the moisture content of the coal water slurry; the two functions can effectively improve the heat value of the coal water slurry and reduce the ash melting point, thereby being better applied to the gasification field.

The following technical solutions are preferred technical solutions of the present invention, but not limited to the technical solutions provided by the present invention, and technical objects and advantageous effects of the present invention can be better achieved and achieved by the following technical solutions.

As a preferred technical scheme of the invention, the raw material coal in the step (1) comprises any one or a combination of at least two of lignite, bituminous coal or anthracite, and typical but non-limiting examples of the combination are as follows: combinations of lignite and bituminous coal, combinations of bituminous and anthracite coal, combinations of lignite, bituminous and anthracite coal, and the like.

Preferably, in the step (1), the first slurry is prepared by mixing the raw material coal, the petroleum coke and the fly ash at a mass ratio of (6-9): (1-3): 0-1, for example, 6:1:0.1, 6:2:0.5, 6:3:1, 7:1:0.2, 7:2:0.8, 7:3:0.6, 8:2:0.4, 9:1:0.3 or 9:3:0.05, but not limited to the above-mentioned values, and other values in the above-mentioned value range are also applicable, and preferably (7-9): 1-2): 0-1.

Preferably, the first slurry is crushed in step (1) to a particle size of no greater than 5mm, such as 5mm, 4.5mm, 4mm, 3.5mm, 3mm, 2.5mm, 2mm, 1mm, or 0.5mm, but not limited to the recited values, and other values not recited within the range of values are equally applicable, preferably 1 to 4 mm.

In a preferred embodiment of the present invention, when the second slurry is prepared in step (1), the mass ratio of the water, the additive, the petroleum coke and the fly ash is (7-21): (0.1-1): (50-55): (24-43), for example, 7:0.1:50:24, 7:0.1:52:30, 7:0.1:55:35, 14:0.5:50:25, 14:1:55:40, 21:0.2:50:30 or 21:0.6:52:35, but is not limited to the above-mentioned values, and other values not listed in the above-mentioned value range are also applicable, and preferably (7-18): 0.1-1): 52-55): 25-35.

Preferably, in the step (1) of preparing the second slurry, the petroleum coke and the fly ash are first crushed to a particle size of 25 to 80 μm, such as 25 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm or 80 μm, but not limited to the values listed, and other values not listed in the range of the values are also applicable.

As a preferred embodiment of the present invention, the additive in step (1) comprises any one of lignosulfonate, humate or naphthalene sulfonic acid formaldehyde condensate or a combination of at least two thereof, and the combination is exemplified by, typically but not limited to: combinations of lignosulfonates and humates, combinations of humates and naphthalene sulfonic acid formaldehyde condensates, combinations of lignosulfonates, humates and naphthalene sulfonic acid formaldehyde condensates, and the like.

According to the invention, the addition of the additive can adjust the viscosity of the mixed raw materials and the stability and water separation performance of the coal slurry, so that the stability of the viscosity of the coal water slurry is ensured, and the proper additive and the usage amount thereof are selected, so that the fluidity and the stability are not influenced due to the increase of the viscosity while the concentration of the coal water slurry is increased.

As a preferable technical scheme of the invention, the mixing and stirring in the step (2) are carried out in a double-shaft stirring kettle.

Preferably, when the first slurry and the second slurry are mixed in step (2), the proportion of the first slurry is 35 to 45 wt%, for example, 35 wt%, 36 wt%, 38 wt%, 40 wt%, 42 wt% or 45 wt%, but not limited to the recited values, and other values not recited in the range of the values are also applicable.

In a preferred embodiment of the present invention, the particle size of the fourth slurry obtained by the shaping and fine grinding in step (2) is 25 to 70 μm, for example, 25 μm, 30 μm, 40 μm, 50 μm, 60 μm, or 70 μm, but the particle size is not limited to the above-mentioned values, and other values not shown in the above-mentioned value range are also applicable, and preferably 30 to 60 μm.

In a preferred embodiment of the present invention, the mesh number of the sieving device used in the sieving in the step (3) is 200 to 400 mesh, for example, 200 mesh, 230 mesh, 250 mesh, 270 mesh, 300 mesh, 325 mesh, or 400 mesh, but is not limited to the above-mentioned numerical values, and other numerical values not listed in the numerical value range are also applicable.

In a preferred embodiment of the present invention, the sixth slurry mixed with the second slurry in the step (1) returned to the step (4) is 40 to 60 wt%, for example, 40 wt%, 42 wt%, 45 wt%, 48 wt%, 50 wt%, 54 wt%, 57 wt%, or 60 wt%, but is not limited to the above-mentioned values, and other values not shown in the above-mentioned range are also applicable.

In a preferred embodiment of the present invention, the coal-water slurry of step (4) has a concentration of 67.5 wt% or more, for example, 67.5 wt%, 68 wt%, 69 wt%, 70 wt%, 71 wt%, 72 wt%, 73 wt%, or 74 wt%, but is not limited to the recited values, and other values not recited in the above range are also applicable.

Preferably, the average particle size of the coal water slurry in the step (4) is 30 to 70 μm, such as 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 60 μm, 65 μm or 70 μm, but is not limited to the listed values, and other values in the range are also applicable, preferably 30 to 65 μm.

As a preferred technical scheme of the invention, the method comprises the following steps:

(1) mixing raw material coal, petroleum coke and fly ash according to the mass ratio of (6-9) to (1-3) to (0-1), crushing, and crushing until the particle size is not more than 5mm to obtain first slurry; crushing petroleum coke and fly ash to a particle size of 25-80 μm, and mixing and stirring the crushed petroleum coke and fly ash with water and an additive according to a mass ratio of (50-55): 24-43): 7-21): 0.1-1 to obtain a second slurry;

(2) introducing the first slurry and the second slurry obtained in the step (1) into a double-shaft stirring kettle for mixing and stirring, wherein the first slurry accounts for 35-45 wt% to obtain a third slurry, and then shaping and fine grinding to obtain a fourth slurry with the particle size of 25-70 microns;

(3) screening the fourth slurry obtained in the step (2), wherein the mesh number of screening equipment used for screening is 200-400 meshes, the screened slurry is a fifth slurry, and the screen residue is a sixth slurry;

(4) returning the sixth slurry with the mass fraction of 40-60 wt% obtained in the step (3) to the step (1) to be mixed with the second slurry, and returning the remaining sixth slurry to the step (2) to perform shaping and fine grinding; and (4) outputting the fifth slurry obtained in the step (3) to obtain the coal water slurry, wherein the concentration of the coal water slurry is more than 67.5 wt%, and the average particle size is 30-70 μm.

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

(1) the method adopts a coal blending technology, petroleum coke and fly ash are added on the basis of raw material coal to form blended coal, and the blended coal improves the slurrying performance of coal and the concentration of the coal water slurry, and can reach more than 67.5 wt%, so that the heat value and the gasification efficiency of the coal water slurry are improved, and the coal water slurry is better used as gasified coal water slurry;

(2) the method of the invention can improve the stacking efficiency of the coal water slurry and reduce the moisture content of the coal water slurry by matching the granularity of the coal components;

(3) the method is simple and convenient to operate, and can effectively reduce the cost of raw materials and energy consumption.

Drawings

Fig. 1 is a process flow chart of a preparation method of blended coal-water slurry provided in embodiment 1 of the present invention.

Detailed Description

In order to better illustrate the present invention and facilitate the understanding of the technical solutions of the present invention, the following embodiments are only simple examples of the present invention and do not represent or limit the scope of the present invention, which is defined by the claims.

The specific embodiment of the invention provides a preparation method of blended coal-water slurry, which comprises the following steps:

(1) mixing and crushing raw material coal, petroleum coke and fly ash to obtain first slurry; mixing petroleum coke, fly ash, water and an additive to obtain a second slurry;

(2) mixing and stirring the first slurry and the second slurry obtained in the step (1) to obtain a third slurry, and then shaping and fine grinding the third slurry to obtain a fourth slurry;

(3) screening the fourth slurry obtained in the step (2), wherein the screened slurry is a fifth slurry, and the screen residue is a sixth slurry;

(4) returning part of the sixth slurry obtained in the step (3) to the step (1) to be mixed with the second slurry, and returning the rest of the sixth slurry to the step (2) to carry out shaping and fine grinding; and (4) outputting the fifth slurry obtained in the step (3) to obtain the coal water slurry.

The following are typical but non-limiting examples of the invention:

example 1:

the embodiment provides a preparation method of blended coal-water slurry, and a process flow chart of the method is shown in fig. 1, and the method comprises the following steps:

(1) mixing raw material coal, petroleum coke and fly ash according to the mass ratio of 6:3:1, crushing until the particle size is not more than 4mm, and obtaining first slurry; crushing petroleum coke and fly ash to a particle size of 50-60 mu m, and mixing and stirring the crushed petroleum coke and fly ash with water and additive sodium lignosulfonate according to a mass ratio of 50:28:21:1 to obtain a second slurry;

(2) introducing the first slurry and the second slurry obtained in the step (1) into a double-shaft stirring kettle for mixing and stirring, wherein the first slurry accounts for 40 wt% to obtain a third slurry, and then shaping and fine grinding to obtain a fourth slurry with the particle size of 45-55 microns;

(3) screening the fourth slurry obtained in the step (2), wherein the mesh number of screening equipment used for screening is 300 meshes, the screened slurry is fifth slurry, and the screen residue is sixth slurry;

(4) returning the sixth slurry with the mass fraction of 50 wt% obtained in the step (3) to the step (1) to be mixed with the second slurry, and returning the remaining sixth slurry to the step (2) to carry out shaping and fine grinding; and (4) outputting the fifth slurry obtained in the step (3) to a coal slurry tank to obtain the coal water slurry.

In the embodiment, the concentration of the obtained coal water slurry product reaches 73.9 wt%, the average particle size is 48 mu m, and the viscosity is 1058mPa & s.

Example 2:

the embodiment provides a preparation method of blended coal-water slurry, which comprises the following steps:

(1) mixing raw material coal, petroleum coke and fly ash according to the mass ratio of 8.8:1:0.2, crushing the raw material coal, the petroleum coke and the fly ash until the particle size is not more than 1mm, and obtaining first slurry; crushing petroleum coke and fly ash to a particle size of 32-40 mu m, and mixing and stirring the crushed petroleum coke and fly ash with water and an additive sodium humate according to a mass ratio of 55:35:9.5:0.5 to obtain a second slurry;

(2) introducing the first slurry and the second slurry obtained in the step (1) into a double-shaft stirring kettle for mixing and stirring, wherein the first slurry accounts for 35 wt% to obtain a third slurry, and then shaping and fine grinding to obtain a fourth slurry with the particle size of 30-40 mu m;

(3) screening the fourth slurry obtained in the step (2), wherein the mesh number of screening equipment used for screening is 400 meshes, the screened slurry is fifth slurry, and the screen residue is sixth slurry;

(4) returning the sixth slurry with the mass fraction of 40 wt% obtained in the step (3) to the step (1) to be mixed with the second slurry, and returning the remaining sixth slurry to the step (2) to carry out shaping and fine grinding; and (4) outputting the fifth slurry obtained in the step (3) to a coal slurry tank to obtain the coal water slurry.

In the embodiment, the concentration of the obtained coal water slurry product reaches 67.5 wt%, the average particle size is 35 mu m, and the viscosity is 1300mPa & s.

Example 3:

the embodiment provides a preparation method of blended coal-water slurry, which comprises the following steps:

(1) mixing raw material coal, petroleum coke and fly ash according to the mass ratio of 8:1.5:0.5, crushing the mixture until the particle size is not more than 2mm, and obtaining first slurry; crushing petroleum coke and fly ash to a particle size of 70-80 mu m, and mixing and stirring the crushed petroleum coke and fly ash with water and an additive naphthalene sulfonic acid formaldehyde condensate according to a mass ratio of 52:30:17.9:0.1 to obtain a second slurry;

(2) introducing the first slurry and the second slurry obtained in the step (1) into a double-shaft stirring kettle for mixing and stirring, wherein the first slurry accounts for 45 wt% to obtain a third slurry, and then shaping and fine grinding to obtain a fourth slurry with the particle size of 60-70 microns;

(3) screening the fourth slurry obtained in the step (2), wherein the mesh number of screening equipment used for screening is 230 meshes, the screened slurry is fifth slurry, and the screen residue is sixth slurry;

(4) returning the sixth slurry with the mass fraction of 60 wt% obtained in the step (3) to the step (1) to be mixed with the second slurry, and returning the remaining sixth slurry to the step (2) to carry out shaping and fine grinding; and (4) outputting the fifth slurry obtained in the step (3) to a coal slurry tank to obtain the coal water slurry.

In the embodiment, the concentration of the obtained coal water slurry product reaches 69.9 wt%, the average particle size is 63 mu m, and the viscosity is 1258mPa & s.

Example 4:

the embodiment provides a preparation method of blended coal-water slurry, which comprises the following steps:

(1) mixing raw material coal, petroleum coke and fly ash according to a mass ratio of 7:2.3:0.7, crushing the mixture until the particle size is not more than 5mm, and obtaining first slurry; crushing petroleum coke and fly ash to a particle size of 40-50 mu m, and mixing and stirring the crushed petroleum coke and fly ash with water and an additive sodium humate according to a mass ratio of 54:31.2:14:0.8 to obtain a second slurry;

(2) introducing the first slurry and the second slurry obtained in the step (1) into a double-shaft stirring kettle for mixing and stirring, wherein the first slurry accounts for 42 wt% to obtain a third slurry, and then shaping and fine grinding to obtain a fourth slurry with the particle size of 40-50 mu m;

(3) screening the fourth slurry obtained in the step (2), wherein the mesh number of screening equipment used for screening is 325 meshes, the screened slurry is fifth slurry, and the screen residue is sixth slurry;

(4) returning the sixth slurry with the mass fraction of 55 wt% obtained in the step (3) to the step (1) to be mixed with the second slurry, and returning the remaining sixth slurry to the step (2) to carry out shaping and fine grinding; and (4) outputting the fifth slurry obtained in the step (3) to a coal slurry tank to obtain the coal water slurry.

In the embodiment, the concentration of the obtained coal water slurry product reaches 69.5 wt%, the average particle size is 43 mu m, and the viscosity is 1158mPa & s.

Example 5:

the embodiment provides a preparation method of blended coal-water slurry, which comprises the following steps:

(1) mixing raw material coal and petroleum coke according to the mass ratio of 8.5:1.5, crushing until the particle size is not more than 3mm, and obtaining first slurry; crushing petroleum coke and fly ash to a particle size of 60-70 mu m, and mixing and stirring the crushed petroleum coke and fly ash with water and additive sodium lignosulfonate according to a mass ratio of 51:40:8.7:0.3 to obtain a second slurry;

(2) introducing the first slurry and the second slurry obtained in the step (1) into a double-shaft stirring kettle for mixing and stirring, wherein the first slurry accounts for 38 wt% to obtain a third slurry, and then shaping and fine grinding to obtain a fourth slurry with the particle size of 50-64 mu m;

(3) screening the fourth slurry obtained in the step (2), wherein the mesh number of screening equipment used for screening is 250 meshes, the screened slurry is fifth slurry, and the screen residue is sixth slurry;

(4) returning the sixth slurry with the mass fraction of 45 wt% obtained in the step (3) to the step (1) to be mixed with the second slurry, and returning the remaining sixth slurry to the step (2) to carry out shaping and fine grinding; and (4) outputting the fifth slurry obtained in the step (3) to a coal slurry tank to obtain the coal water slurry.

In the embodiment, the concentration of the obtained coal water slurry product reaches 68.5 wt%, the average particle size is 55 mu m, and the viscosity is 1109mPa & s.

Comparative example 1:

this comparative example provides a method of making a blended coal water slurry, which is referenced to the method of example 1, except that: in the step (1), the raw material coal is directly crushed and then mixed with water and an additive, and is not divided into a first slurry and a second slurry.

In the comparative example, because petroleum coke and fly ash are not used as the matching components of the raw material coal, and low-rank coal is independently used as the raw material of the coal water slurry, the slurry forming performance is reduced, the concentration of the obtained coal water slurry is reduced to 45 wt%, the gasification efficiency is reduced, and the gasification requirement cannot be met; meanwhile, the cooperation of the particle sizes among the particles is weakened, and the moisture content is relatively high.

Comparative example 2:

this comparative example provides a method of making a blended coal water slurry, which is referenced to the method of example 1, except that: and (2) no additive is added during the preparation of the second slurry in the step (1), and the mass proportion of the additive is replaced by water.

In the comparative example, because no additive is added in the preparation process of the coal water slurry, the viscosity of the coal water slurry is increased to 2000mPa & s while the concentration of the coal water slurry is increased, so that the fluidity of the coal water slurry is reduced, and the application of the coal water slurry is not facilitated.

It can be seen from the above examples and comparative examples that the method of the invention adopts the coal blending technique, add petroleum coke and fly ash to form the blending coal on the basis of raw material coal, the said blending coal improves the slurry-forming performance of the coal kind and concentration of the coal water slurry, can reach more than 67.5 wt%, thus raise the calorific value and gasification efficiency of the coal water slurry, better use as gasifying the coal water slurry; the combination of the granularity of the coal components can improve the stacking efficiency of the coal water slurry and reduce the moisture content of the coal water slurry; the method is simple and convenient to operate, and can effectively reduce the cost of raw materials and energy consumption.

The applicant states that the present invention is illustrated in detail by the above examples, but the present invention is not limited to the above detailed methods, i.e. it does not mean that the present invention must rely on the above methods for its implementation. It will be apparent to those skilled in the art that any modifications to the invention, equivalents of the materials used, additions of auxiliary materials, and operations, and selection of particular means, are within the scope and disclosure of the invention.

Claims (13)

1. A preparation method of blended coal water-coal slurry is characterized by comprising the following steps:

(1) mixing and crushing raw material coal, petroleum coke and fly ash, wherein the mixing mass ratio of the raw material coal, the petroleum coke and the fly ash is (6-9) to (1-3) to (0-1), so as to obtain first slurry, and the particle size of the first slurry is not more than 5 mm; mixing petroleum coke, fly ash, water and an additive, wherein the mass ratio of the water to the additive to the petroleum coke to the fly ash is (7-21): 0.1-1): 50-55): 24-43, so as to obtain a second slurry, and crushing the petroleum coke and the fly ash to the particle size of 25-80 μm when preparing the second slurry;

(2) mixing and stirring the first slurry and the second slurry obtained in the step (1), wherein the first slurry accounts for 35-45 wt% to obtain a third slurry, and then shaping and fine grinding the third slurry to obtain a fourth slurry, wherein the particle size of the fourth slurry is 25-70 mu m;

(3) screening the fourth slurry obtained in the step (2), wherein the mesh number of screening equipment used for screening is 200-400 meshes, the screened slurry is a fifth slurry, and the screened residue is a sixth slurry;

(4) returning 40-60 wt% of sixth slurry obtained in the step (3) to the step (1) to be mixed with the second slurry, and returning the rest sixth slurry to the step (2) for shaping and fine grinding; and (4) outputting the fifth slurry obtained in the step (3) to obtain the coal water slurry.

2. The method according to claim 1, wherein the raw material coal of step (1) comprises any one of lignite, bituminous coal or anthracite coal or a combination of at least two of lignite, bituminous coal and anthracite coal.

3. The preparation method according to claim 1, wherein the raw material coal, the petroleum coke and the fly ash are mixed in a mass ratio of (7-9) to (1-2) to (0-1) when the first slurry is prepared in the step (1).

4. The method according to claim 1, wherein the step (1) is carried out until the first slurry has a particle size of 1-4 mm.

5. The method according to claim 1, wherein the mass ratio of the water, the additive, the petroleum coke and the fly ash is (7-18): (0.1-1): (52-55): (25-35) when the second slurry is prepared in the step (1).

6. The method according to claim 1, wherein the additive in step (1) comprises any one of lignosulfonate, humate or naphthalene sulfonic acid formaldehyde condensate or a combination of at least two thereof.

7. The method according to claim 1, wherein the mixing and stirring in step (2) are carried out in a double-shaft stirred tank.

8. The preparation method according to claim 1, wherein the particle size of the fourth slurry obtained after the shaping and fine grinding in the step (2) is 30 to 60 μm.

9. The preparation method according to claim 1, wherein the screening equipment used in the screening in the step (3) has a mesh number of 250-325 meshes.

10. The method according to claim 1, wherein the concentration of the coal-water slurry in the step (4) is 67.5 wt% or more.

11. The preparation method according to claim 1, wherein the average particle size of the coal water slurry in the step (4) is 30-70 μm.

12. The preparation method according to claim 11, wherein the average particle size of the coal water slurry in the step (4) is 30-65 μm.

13. The method for preparing according to claim 1, characterized in that it comprises the following steps:

(1) mixing raw material coal, petroleum coke and fly ash according to the mass ratio of (6-9) to (1-3) to (0-1), crushing, and crushing until the particle size is not more than 5mm to obtain first slurry; crushing petroleum coke and fly ash to a particle size of 25-80 μm, and mixing and stirring the crushed petroleum coke and fly ash with water and an additive according to a mass ratio of (50-55): 24-43): 7-21): 0.1-1 to obtain a second slurry;

(2) introducing the first slurry and the second slurry obtained in the step (1) into a double-shaft stirring kettle for mixing and stirring, wherein the first slurry accounts for 35-45 wt% to obtain a third slurry, and then shaping and fine grinding to obtain a fourth slurry with the particle size of 25-70 microns;

(3) screening the fourth slurry obtained in the step (2), wherein the mesh number of screening equipment used for screening is 200-400 meshes, the screened slurry is a fifth slurry, and the screen residue is a sixth slurry;

(4) returning the sixth slurry with the mass fraction of 40-60 wt% obtained in the step (3) to the step (1) to be mixed with the second slurry, and returning the remaining sixth slurry to the step (2) to perform shaping and fine grinding; and (4) outputting the fifth slurry obtained in the step (3) to obtain the coal water slurry, wherein the concentration of the coal water slurry is more than 67.5 wt%, and the average particle size is 30-70 μm.

Images