阅读说明：本技术 水煤浆及其制备方法和合成气的制备方法 (Coal water slurry, preparation method thereof and preparation method of synthesis gas ) 是由 江永军 苏慧 庄壮 金政伟 张安贵 李瑞龙 蒙延斐 颜蜀雋 赵娜娜 王倩 于 2021-01-12 设计创作，主要内容包括：本发明涉及水煤浆技术领域,公开了一种水煤浆及其制备方法和合成气的制备方法,该方法包括：将MTP工艺废水的pH值调节至大于8,然后与化学添加剂、水混合,得到浆液；将所述浆液与煤、废MTP催化剂进行混合、研磨,得到水煤浆。本发明通过以MTP工艺废水、化学添加剂、水、煤和废MTP催化剂为原料制备得到的水煤浆具有粒度分布均匀,成浆浓度高,表观粘度小,流动性好的特点；将该水煤浆用于制备合成气时,能够有效提高水煤浆的利用率和合成气的产率。(The invention relates to the technical field of coal water slurry, and discloses coal water slurry, a preparation method thereof and a preparation method of synthesis gas, wherein the method comprises the following steps: adjusting the pH value of the MTP process wastewater to be more than 8, and then mixing the MTP process wastewater with a chemical additive and water to obtain slurry; and mixing and grinding the slurry, coal and the waste MTP catalyst to obtain the coal water slurry. The coal water slurry prepared by using the MTP process wastewater, the chemical additive, the water, the coal and the waste MTP catalyst as raw materials has the characteristics of uniform particle size distribution, high slurry concentration, small apparent viscosity and good fluidity; when the coal water slurry is used for preparing synthesis gas, the utilization rate of the coal water slurry and the yield of the synthesis gas can be effectively improved.)

1. A preparation method of coal water slurry is characterized by comprising the following steps: adjusting the pH value of the MTP process wastewater to be more than 8, and then mixing the MTP process wastewater with a chemical additive and water to obtain slurry; and mixing and grinding the slurry, coal and the waste MTP catalyst to obtain the coal water slurry.

2. The method of claim 1 wherein the pH of the MTP process wastewater is adjusted to 8-9;

preferably, the COD value of the MTP process wastewater is 1000-100000mg/L, and more preferably is 6000-80000 mg/L.

3. The method of claim 1 or 2, wherein the spent MTP catalyst comprises SiO₂、Al₂O₃And Na₂O, SiO based on the total amount of the waste MTP catalyst₂Is 30-32 wt% of Al₂O₃The content of (B) is 66-68 wt%, Na₂The content of O is 0.05 to 2.5 weight percent;

preferably, the carbon content of the spent MTP catalyst is from 0.5 to 35 wt%, preferably from 15 to 35 wt%; the C/H molar ratio is 5-20, preferably 7-10;

preferably, the coal contains 16 to 21 wt% water, 9 to 24 wt% ash, 28 to 37 wt% volatiles and 49 to 61 wt% carbon;

preferably, the coal is selected from at least one of lignite, long flame coal, non-sticky coal and weakly sticky coal.

4. The method of any one of claims 1 to 3, wherein the weight ratio of the MTP process wastewater, the chemical additive, the water, the coal and the waste MTP catalyst is (1-20): (0.1-5): (15-30): (40-65): (10-30), preferably (3-8): (3-5): (15-25): (45-60): (15-20).

5. The method according to any one of claims 1 to 4, wherein the chemical additive is selected from at least one of synthetic organic high molecular surfactants, lignin surfactants and humic acid surfactants;

more preferably, the synthetic organic polymer surfactant is at least one selected from the group consisting of naphthalenesulfonic acid formaldehyde condensate surfactants, aminosulfonate surfactants, polycarboxylate surfactants, polyolefin sulfonate surfactants, and aliphatic hydroxysulfonate polycondensate surfactants;

further preferably, the lignin-based surfactant is selected from alkali lignin-based surfactants and/or lignosulfonate-based surfactants;

further, the humic acid surfactant is at least one selected from the group consisting of a phenol hydroxyhumic acid salt surfactant, an enol humic acid salt surfactant, a sulfonic humic acid salt surfactant and a methoxy humic acid salt surfactant.

6. The method of any one of claims 1-5, wherein prior to adjusting the pH of the MTP process wastewater to greater than 8, the method further comprises: heating the MTP process wastewater to 40-70 ℃.

7. The process of any of claims 1-6, wherein prior to mixing the slurry with coal, spent MTP catalyst, the process further comprises: respectively crushing the coal and the waste MTP catalyst to obtain the coal with the average grain diameter of 10-100 mu m and the waste MTP catalyst with the average grain diameter of 10-50 mu m.

8. The water-coal-slurry prepared by the method of any one of claims 1 to 7, wherein the apparent viscosity of the water-coal-slurry is less than 2000 mPa-s, the concentration of the water-coal-slurry is 50 to 80 wt%, and the average particle size of the water-coal-slurry is 70 to 90 μm.

9. The coal-water slurry according to claim 8, wherein the apparent viscosity of the coal-water slurry is 1000-1400mPa · s, the concentration of the coal-water slurry is 57-65 wt%, and the average particle size of the coal-water slurry is 70-85 μm.

10. A process for the production of synthesis gas, the process comprising: the coal water slurry of claim 8 or 9 is mixed with oxygen to carry out gasification reaction to obtain synthesis gas.

11. The method of claim 10, wherein the volume ratio of coal-water slurry to oxygen is 1: 300-450;

preferably, the conditions of the gasification reaction include: the temperature is 1000 ℃ and 1500 ℃, and the pressure is 2-5 MPa.

Technical Field

The invention relates to the technical field of coal water slurry, in particular to coal water slurry, a preparation method thereof and a preparation method of synthesis gas.

Background

Coal water slurry is a new type, high efficiency and clean coal-based fuel, is a new member of fuel families, and is a mixture prepared by 65-70% of coal powder with different particle size distributions, about 29-34% of water and about 1% of chemical additives. It has petroleum-like fluidity and a calorific value equivalent to half of that of oil, and is called a liquid coal product. The coal water slurry can keep the physical and chemical properties of coal, has good fluidity and stability like petroleum, is easy to store and adjust, is a low-pollution clean fuel, can be atomized and combusted, and has high combustion efficiency.

At present, the preparation method of the coal water slurry comprises the following steps: coal is used as raw material, and a conventional mill pulping process is adopted, and the coal, water and additives are added into a rod mill or a ball mill according to a certain proportion, and a coal water slurry product is prepared by primary grinding. However, the coal water slurry prepared by the process has uneven granularity, low coal slurry concentration and poor fluidity, so that the utilization rate of the coal water slurry and the yield of synthesis gas are generally low.

Therefore, the provision of a new coal water slurry and a preparation method thereof has important significance.

Disclosure of Invention

The invention aims to solve the problems of uneven particle size distribution, large viscosity, low concentration of formed slurry and poor fluidity of the existing coal water slurry, and further causes the utilization rate of the coal water slurry and the yield of synthesis gas to be low, and provides the coal water slurry, the preparation method thereof and the preparation method of the synthesis gas.

In order to achieve the above object, a first aspect of the present invention provides a method for producing a coal water slurry, comprising: adjusting the pH value of the MTP process wastewater to be more than 8, and then mixing the MTP process wastewater with a chemical additive and water to obtain slurry; and mixing and grinding the slurry, coal and the waste MTP catalyst to obtain the coal water slurry.

The second aspect of the invention provides the coal water slurry prepared by the method of the first aspect of the invention, wherein the apparent viscosity of the coal water slurry is less than 2000mPa · s, the concentration of the coal water slurry is 50-80 wt%, and the average particle size of the coal water slurry is 70-90 μm.

In a third aspect, the present invention provides a process for the production of synthesis gas, the process comprising: the coal water slurry of the second aspect of the invention is mixed with oxygen for gasification reaction to obtain synthesis gas.

By adopting the technical scheme, the coal water slurry prepared by using the MTP process wastewater, the chemical additive, the water, the coal and the waste MTP catalyst as raw materials has the characteristics of uniform particle size distribution, high slurry concentration, small apparent viscosity and good fluidity; when the coal water slurry is used for preparing synthesis gas, the utilization rate of the coal water slurry and the yield of the synthesis gas can be effectively improved. For example, when the coal water slurry prepared in example 1 of the present invention is used for preparing synthesis gas, the synthesis gas (CO + H)₂) The yield can reach 83.2 percent, and the utilization rate of the coal water slurry can reach 98.5 percent; when the coal water slurry prepared in the comparative example 1 is used for preparing synthesis gas, the synthesis gas (CO + H) is prepared under the same conditions₂) The yield of the coal water slurry is only 80.3 percent, and the utilization rate of the coal water slurry is only 95.3 percent. The preparation method provided by the invention is simple in process flow, easy to implement and capable of realizing resource utilization of waste.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

Coal water slurry can be obtained by grinding coal, water and additives which are used as raw materials at present, but the coal water slurry obtained by the method has the defects of uneven particle size distribution, low slurry concentration, large viscosity and poor fluidity, so that the yield of synthesis gas and the utilization rate of the coal water slurry are not high. In order to solve the above problems, the inventors of the present invention have found in their research that the coal water slurry obtained by mixing and grinding coal, water, a chemical additive, MTP process wastewater and a waste MTP catalyst has the characteristics of uniform particle size distribution, high slurry concentration, low apparent viscosity and good fluidity, and when the coal water slurry is used for preparing synthesis gas, the effects of improving the yield of synthesis gas and the utilization rate of the coal water slurry can be obtained. The reason for this is probably that the coal water slurry obtained by the mutual cooperation of the coal, the water, the chemical additive, the MTP process wastewater and the waste MTP catalyst has better performance under the combined action, thereby improving the yield of the synthesis gas and the utilization rate of the coal water slurry. In addition, the inventors of the present invention have further found that by using MTP process wastewater with COD value of 1000-100000mg/L, preferably 6000-80000mg/L, the carbon content is 0.5-35 wt%, preferably 15-35 wt%, the C/H molar ratio is 5-20, preferably 7-10, and 30-32 wt% of SiO is contained₂66-68 wt% of Al₂O₃And 0.05-2.5 wt% of Na₂The water-coal-slurry prepared by mixing the waste MTP catalyst of O, coal, water and a chemical combination additive according to a specific ratio has better performance, so that the yield of synthesis gas and the utilization rate of the water-coal-slurry can be further improved.

As described above, the first aspect of the present invention provides a method for producing a coal water slurry, the method comprising: adjusting the pH value of the MTP process wastewater to be more than 8, and then mixing the MTP process wastewater with a chemical additive and water to obtain slurry; and mixing and grinding the slurry, coal and the waste MTP catalyst to obtain the coal water slurry. The mixing according to the invention can be carried out under stirring.

In some embodiments of the present invention, it is preferable to adjust the pH of the MTP process wastewater to 8-9, which is more advantageous to prepare coal water slurry with better performance.

The invention has no special limitation on the source of the MTP process wastewater, and can adopt wastewater with organic matters generated by reaction processes such as a fixed bed, a fluidized bed, a moving bed and the like.

In some embodiments of the present invention, the MTP process wastewater is not particularly limited, and preferably, the COD value of the MTP process wastewater is 1000-. In this preferred case, it is more advantageous to convert organic matter in the MTP process wastewater into syngas during gasification, thereby further increasing the yield of syngas. In addition, the invention can also reduce the water consumption in the pulping process by adopting the MTP process wastewater.

The method for adjusting the pH value of the MTP process wastewater to be more than 8 is not particularly limited in the invention as long as the MTP process wastewater can be made alkaline, and preferably, the pH value of the MTP process wastewater is adjusted to be more than 8 by using alkali liquor.

The selection range of the alkali liquor is wide, and preferably, the alkali liquor comprises but is not limited to sodium hydroxide solution, potassium hydroxide solution and the like.

The source of the waste MTP catalyst is not particularly limited in the present invention, and a waste MTP catalyst generated by a methanol to propylene reaction in a fixed bed, a fluidized bed or a moving bed reactor may be used, and preferably a waste MTP catalyst generated by a methanol to propylene reaction in a fixed bed or a moving bed reactor is used.

In some embodiments of the present invention, the waste MTP catalyst is not particularly limited, and preferably, the waste MTP catalyst includes SiO₂、Al₂O₃And Na₂O, SiO based on the total amount of the waste MTP catalyst₂Is 30-32 wt% of Al₂O₃The content of (B) is 66-68 wt%, Na₂The content of O is 0.05-2.5 wt%. While the existing fresh MTP catalyst only comprises SiO₂And Al₂O₃Does not contain Na₂O。

In some embodiments of the invention, preferably, the carbon content of the spent MTP catalyst is from 0.5 to 35 wt% and the C/H molar ratio is from 5 to 20. Further preferably, the carbon content of the waste MTP catalyst is 15-35 wt%, and the C/H molar ratio is 7-10. In this preferred case, the yield of synthesis gas can be further increased. In addition, the invention can fully utilize the organic carbon deposition on the surface and in the pore channels of the waste MTP catalyst by taking the waste MTP catalyst as the raw material, thereby reducing the using amount of coal. Whereas the existing fresh MTP catalysts contain no carbon, i.e. the C/H molar ratio is 0.

In some embodiments of the present invention, the coal is not particularly limited, and preferably, the coal contains 16 to 21 wt% of water, 9 to 24 wt% of ash, 28 to 37 wt% of volatile matter, and 49 to 61 wt% of carbon.

The coal is selected from a wide range, and preferably, the coal is selected from at least one of lignite, long flame coal, non-caking coal and weakly caking coal.

In some embodiments of the present invention, the coal water slurry prepared by mixing the MTP process wastewater, the chemical additive, the water, the coal and the waste MTP catalyst in a proper ratio has better performance, so that the yield of the synthesis gas and the utilization rate of the coal water slurry can be further improved, and preferably, the weight ratio of the MTP process wastewater, the chemical additive, the water, the coal and the waste MTP catalyst is (1-20): (0.1-5): (15-30): (40-65): (10-30), more preferably (3-8): (3-5): (15-25): (45-60): (15-20).

In some embodiments of the present invention, the chemical additive is selected from a wide range, and preferably, the chemical additive is selected from at least one of synthetic organic polymer surfactants, lignin surfactants, and humic acid surfactants.

More preferably, the synthetic organic polymer surfactant is at least one selected from the group consisting of naphthalenesulfonic acid formaldehyde condensate surfactants, aminosulfonate surfactants, polycarboxylate surfactants, polyolefin sulfonate surfactants, and aliphatic hydroxysulfonate polycondensate surfactants. Examples include, but are not limited to, sodium polystyrene sulfonate, methoxypolyethylene glycol methacrylate, and the like.

Further preferably, the lignin-based surfactant is selected from alkali lignin-based surfactants and/or lignosulfonate-based surfactants. Examples include, but are not limited to, sodium lignosulfonate, calcium lignosulfonate, magnesium lignosulfonate, ammonium lignosulfonate, and the like.

Further, the humic acid surfactant is at least one selected from the group consisting of a phenol hydroxyhumic acid salt surfactant, an enol humic acid salt surfactant, a sulfonic humic acid salt surfactant and a methoxy humic acid salt surfactant. Examples include, but are not limited to, sodium humate, magnesium humate sulfonate, and the like.

In some embodiments of the present invention, the grinding mode is not particularly limited, and preferably, the slurry is ground by using an existing high-speed grinder, and the rotation speed is preferably 50 to 200 rpm.

In some embodiments of the present invention, preferably, before adjusting the pH of the MTP process wastewater to greater than 8, the method further comprises: the MTP process wastewater is heated to 40-70 ℃, and then the pH value is adjusted to be more than 8. The invention can better fuse the subsequent coal and the waste MTP catalyst in the slurry through the operation.

In some embodiments of the present invention, in order to sufficiently mix the reaction raw materials, preferably, before mixing the slurry with coal and the waste MTP catalyst, the method further comprises: respectively crushing the coal and the waste MTP catalyst to obtain the coal with the average grain diameter of 10-100 mu m and the waste MTP catalyst with the average grain diameter of 10-50 mu m.

The crushing mode is not particularly limited in the present invention, and preferably, the coal and the waste MTP catalyst are crushed separately by using an existing crusher.

In order to clearly describe the method of preparing the coal water slurry of the present invention, a preferred embodiment is provided below for illustration:

heating MTP process wastewater (COD value is 6000-; respectively crushing coal (containing 16-21 wt% of water, 9-24 wt% of ash, 28-37 wt% of volatile components and 49-61 wt% of carbon) and waste MTP catalyst (the carbon content is 15-35 wt%, and the C/H molar ratio is 7-10) by using a crusher to obtain coal with the average particle size of 10-100 mu m and waste MTP catalyst with the average particle size of 10-50 mu m;

then, mixing the slurry with crushed coal and a waste MTP catalyst, and grinding the mixed slurry by adopting a high-speed grinder at the rotating speed of 50-200rpm to obtain coal water slurry;

wherein the weight ratio of the MTP process wastewater, the chemical additive, the water, the coal and the waste MTP catalyst is (3-8): (3-5): (15-25): (45-60): (15-20).

The second aspect of the invention provides the coal water slurry prepared by the method, the apparent viscosity of the coal water slurry is less than 2000mPa & s, the concentration of the coal water slurry is 50-80 wt%, and the average particle size of the coal water slurry is 70-90 μm. The coal water slurry prepared by the method has more uniform particle size distribution, higher slurry concentration, smaller apparent viscosity and better fluidity; when the coal water slurry is used for preparing synthesis gas, the utilization rate of the coal water slurry and the yield of the synthesis gas are improved.

According to a preferred embodiment of the invention, the apparent viscosity of the coal water slurry is 1000-1400 mPa.s, the concentration of the coal water slurry is 57-65 wt%, and the average particle size of the coal water slurry is 70-85 μm.

In a third aspect, the present invention provides a process for the production of synthesis gas, the process comprising: the coal water slurry is mixed with oxygen for gasification reaction to obtain synthesis gas.

In some embodiments of the present invention, preferably, the volume ratio of the coal water slurry to the oxygen is 1: 300-450.

In some embodiments of the invention, preferably, the conditions of the gasification reaction comprise: the temperature is 1000 ℃ and 1500 ℃, and the pressure is 2-5 MPa.

The apparatus for carrying out the gasification reaction in the present invention is not particularly limited, and may be an apparatus conventionally used in the art, for example, a gasification furnace.

In the present invention, the pressure represents a gauge pressure unless otherwise specified.

The present invention will be described in detail below by way of examples. In the following examples, various raw materials used were commercially available unless otherwise specified.

Coal 1 (plum blossom well coal in ningdong mine area): the water content was 17.81 wt%, the ash content was 23.28 wt%, the volatiles content was 36.14 wt%, the carbon content was 51.06 wt%;

coal 2 (mindong mine area Lingxi coal): the water content was 20.23 wt%, the ash content was 9.22 wt%, the volatiles content was 33.56 wt%, the carbon content was 60.31 wt%;

waste MTP catalyst 1: SiO 2₂Is 31 wt% of Al₂O₃Has a content of 67 wt% and Na₂The O content is 2 wt%, the carbon content is 35 wt%, and the C/H molar ratio is 10;

waste MTP catalyst 2: SiO 2₂Is 32 wt% of Al₂O₃Has a content of 67 wt% and Na₂The O content is 1 wt%, the carbon content is 26 wt%, and the C/H molar ratio is 8;

waste MTP catalyst 3: SiO 2₂Is 30 wt% of Al₂O₃Has a content of 67.5 wt% and Na₂The O content was 2.5 wt%, the carbon content was 13.7 wt%, and the C/H molar ratio was 6;

MTP process wastewater 1: the COD value is 36000 mg/L;

MTP process wastewater 2: the COD value is 75000 mg/L;

MTP process wastewater 3: the COD value is 5000 mg/L;

determining the average particle size of the coal water slurry by using a Macike S3500SI laser particle size analyzer;

adopting a density bottle to measure the concentration of the coal water slurry;

measuring the apparent viscosity of the coal water slurry by adopting an NXS-4C rotational rheometer of a Chengdu instrument factory;

yield of syngas (CO + H)₂) Detecting by a gas chromatography FTD detector, and calculating by a peak area correction normalization method;

and (4) calculating.

Example 1

Heating 700g of MTP process wastewater 1 to 50 ℃, adjusting the pH value of the heated MTP process wastewater 1 to 8.5 by using a sodium hydroxide solution, and then mixing and stirring the MTP process wastewater 1 with 300g of chemical additives (comprising 50 wt% of sodium lignosulfonate, 20 wt% of sodium sulfonated humate and 30 wt% of sodium polystyrene sulfonate) and 1500g of water to obtain slurry; respectively crushing 6000g of coal 1 and 1500g of waste MTP catalyst 1 by a crusher to obtain coal 1 with the average particle size of 75 microns and waste MTP catalyst 1 with the average particle size of 50 microns;

and then, mixing the slurry with the crushed coal 1 and the waste MTP catalyst 1, and grinding the mixed slurry by adopting a high-speed grinder at the rotating speed of 200rpm to obtain the coal water slurry.

And (3) standing the obtained coal water slurry for 24h, and observing the state: no demixing and no obvious precipitation. The performance parameters of the coal water slurry are listed in table 1.

Example 2

Heating 500g of MTP process wastewater 2 to 40 ℃, adjusting the pH value of the heated MTP process wastewater 2 to 9 by using a sodium hydroxide solution, and then mixing and stirring the mixture with 400g of chemical additives (comprising 50 wt% of sodium lignosulfonate, 30 wt% of sodium humate and 20 wt% of methoxypolyethylene glycol methacrylate) and 2500g of water to obtain slurry; respectively crushing 4500g of coal 2 and 2000g of waste MTP catalyst 2 by a crusher to obtain coal 2 with the average particle size of 50 microns and waste MTP catalyst 2 with the average particle size of 20 microns;

and then, mixing the slurry with the crushed coal 2 and the waste MTP catalyst 2, and grinding the mixed slurry by adopting a high-speed grinder at the rotating speed of 100rpm to obtain the coal water slurry.

And (3) standing the obtained coal water slurry for 24h, and observing the state: no demixing and no obvious precipitation. The performance parameters of the coal water slurry are listed in table 1.

Example 3

Heating 300g of MTP process wastewater 2 to 70 ℃, adjusting the pH value of the heated MTP process wastewater 2 to 8 by using a sodium hydroxide solution, and then mixing and stirring the MTP process wastewater 2 with 500g of chemical additives (comprising 50 wt% of calcium lignosulfonate and 50 wt% of sodium humate sulfonate) and 2000g of water to obtain slurry; respectively crushing 5000g of coal 2 and 1700g of waste MTP catalyst 1 by a crusher to obtain coal 2 with the average particle size of 100 microns and waste MTP catalyst 1 with the average particle size of 30 microns;

and then, mixing the slurry with crushed coal 2 and the waste MTP catalyst 1, and grinding the mixed slurry by adopting a high-speed grinder at the rotating speed of 150rpm to obtain the coal water slurry.

And (3) standing the obtained coal water slurry for 24h, and observing the state: no demixing and no obvious precipitation. The performance parameters of the coal water slurry are listed in table 1.

Example 4

Coal-water slurry was obtained according to the procedure of example 1 except that "waste MTP catalyst 1" was replaced with "waste MTP catalyst 3".

And (3) standing the obtained coal water slurry for 24h, and observing the state: no demixing, no obvious precipitation and little water separation. The performance parameters of the coal water slurry are listed in table 1.

Example 5

According to the method of the embodiment 1, except that the amount of the MTP process wastewater 1 is changed to 1200g, the amount of the chemical additive is changed to 200g, the amount of the water is changed to 2000g, the amount of the coal 1 is changed to 4500g, and the amount of the waste MTP catalyst 1 is changed to 1200g, so that the coal water slurry is obtained.

And (3) standing the obtained coal water slurry for 24h, and observing the state: no demixing and no obvious precipitation. The performance parameters of the coal water slurry are listed in table 1.

Example 6

According to the method of the embodiment 1, except that the MTP process wastewater 1 is replaced by the MTP process wastewater 3, the coal water slurry is obtained.

And (3) standing the obtained coal water slurry for 24h, and observing the state: no demixing and no obvious precipitation. The performance parameters of the coal water slurry are listed in table 1.

Comparative example 1

Following a procedure similar to example 1, except that no waste MTP catalyst and no MTP process wastewater were added, specifically:

6000g of coal 1 is crushed by a crusher to obtain coal 1 with the average particle size of 75 mu m, the crushed coal 1 is mixed and stirred with 300g of chemical additive (comprising 50 wt% of sodium lignosulfonate, 20 wt% of sodium sulfonated humate and 30 wt% of sodium polystyrene sulfonate) and 1500g of water to obtain slurry, then the pH value of the slurry is adjusted to 8.5 by adopting a sodium hydroxide solution, and finally the slurry is ground by a high-speed grinder at the rotating speed of 200rpm to obtain the coal water slurry.

And (3) standing the obtained coal water slurry for 24h, and observing the state: there is precipitation and obvious water separation. The performance parameters of the coal water slurry are listed in table 1.

Comparative example 2

Following a similar procedure to example 1, except that no chemical additives were added, specifically:

heating 700g of MTP process wastewater 1 to 50 ℃, adjusting the pH value of the heated MTP process wastewater 1 to 8.5 by adopting a sodium hydroxide solution, and then mixing and stirring with 1500g of water to obtain slurry; respectively crushing 6000g of coal 1 and 1500g of waste MTP catalyst 1 by a crusher to obtain coal 1 with the average particle size of 75 microns and waste MTP catalyst 1 with the average particle size of 50 microns;

and then, mixing the slurry with the crushed coal 1 and the waste MTP catalyst 1, and grinding the mixed slurry by adopting a high-speed grinder at the rotating speed of 200rpm to obtain the coal water slurry.

And (3) standing the obtained coal water slurry for 24h, and observing the state: there is precipitation and obvious water separation. The performance parameters of the coal water slurry are listed in table 1.

TABLE 1

Example numbering	Apparent viscosity (mPa. s)	Concentration (wt%)	Average particle diameter (μm)
				Example 1	1005	64.5	75
Example 2	1010	62.06	75
				Example 3	1050	60.22	70
Example 4	1250	58.13	80
				Example 5	1200	57.86	80
Example 6	1350	57	85
				Comparative example 1	2600	56.12	100
Comparative example 2	2000	54.63	85

It can be seen from the results of the examples, comparative examples and table 1 that the coal water slurry obtained by grinding coal, water, the chemical combination additive, the MTP process wastewater and the waste MTP catalyst are mixed, and has the characteristics of more uniform particle size distribution, higher slurry concentration, smaller apparent viscosity and better fluidity. Preferably, the apparent viscosity of the coal water slurry is within the range of 1000-1100 mPas, the concentration is within the range of 60-65 wt%, and the average particle size is within the range of 70-75, so that the coal water slurry has better fluidity. In the prior art, coal water slurry prepared by taking coal, water and additives as raw materials or coal, water, MTP process wastewater and a waste MTP catalyst as raw materials has the defects of uneven particle size distribution, low slurry concentration, large apparent viscosity and poor fluidity.

Test examples 1 to 6

Respectively introducing the coal water slurry prepared in the embodiment 1-6 into a gasification furnace, and mixing the coal water slurry with oxygen simultaneously introduced into the gasification furnace for gasification reaction, wherein the volume ratio of the coal water slurry to the oxygen is 1: 400 at 1300 deg.C and 3.5MPa, and measuring the content of synthetic gas (CO + H) at the outlet of the gasifier₂) The yield of the synthesis gas and the utilization rate of the coal water slurry are calculated, and the results are listed in table 2.

Comparative test examples 1 to 2

Respectively introducing the coal water slurry prepared in the comparative example 1-2 into a gasification furnace, and simultaneously introducing oxygen into the gasification furnace to mix for gasification reaction, wherein the volume ratio of the coal water slurry to the oxygen is 1: 400 at 1300 deg.C and 3.5MPa, and measuring the content of synthetic gas (CO + H) at the outlet of the gasifier₂) And calculateThe yield of synthesis gas obtained and the utilization of the coal-water slurry are shown in table 2.

TABLE 2

As can be seen from the results in Table 2, when the coal water slurry provided by the invention is used for preparing synthesis gas, the synthesis gas (CO + H)₂) The yield of the coal water slurry reaches more than 81 percent, and the utilization rate of the coal water slurry reaches more than 97 percent. Preferably, the synthesis gas is (CO + H)₂) The yield of the coal water slurry is in the range of 82-84%, and the utilization rate of the coal water slurry is in the range of 98-99%. When the coal water slurry prepared by the prior art is used for preparing synthesis gas, the synthesis gas (CO + H)₂) The yield of the coal water slurry is only 80.3 percent or 79.93 percent, and the utilization rate of the coal water slurry is only 95.3 percent or 94.7 percent. Therefore, when the coal water slurry provided by the invention is used for preparing the synthesis gas, the yield of the synthesis gas and the utilization rate of the coal water slurry are obviously improved.

In addition, the price of coal is 500 yuan/ton, the price of water is 3.3 yuan/ton, and the treatment cost of waste MTP catalyst and MTP process wastewater is 3000 yuan/ton. Compared with the coal water slurry prepared without adding the waste MTP catalyst and the MTP process wastewater, when 10-30 wt% of the waste MTP catalyst and 1-20 wt% of the MTP process wastewater are added in the preparation process of the coal water slurry, the cost of 50-150 yuan coal can be saved for preparing each ton of the coal water slurry, the cost of 0.03-0.3 yuan water can be saved, and the treatment cost of 300-900 yuan waste MTP catalyst and MTP process wastewater can be reduced. The coal water slurry prepared by the preparation method of the invention can increase the yield of 350.03-1050.03 yuan in each ton of coal water slurry preparation process, and the economic benefit is very obvious.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.