CN116948711A - Raw material pretreatment method and pretreatment system for entrained flow gasifier - Google Patents

Abstract

The disclosure relates to the technical field of coal chemical industry, and provides a raw material pretreatment method and a pretreatment system for an entrained flow gasifier. The raw material pretreatment method for the entrained flow gasifier is used for carrying out pretreatment and crushing treatment on raw material coal and/or solid waste to obtain crushed coal and improve the contact area; the crushed coal is sent to a pretreatment unit for crushing treatment, water removal and oxygen-containing functional group reduction, so that pulverized coal is obtained, the hydrophobicity of the pulverized coal is improved, and the pulverized coal has good slurrying property; the pulverized coal is sent into a water washing unit to be subjected to water washing treatment, water-soluble cations in the pulverized coal are removed, wet pulverized coal is obtained, and the influence of the cations on the fluidity of the coal water slurry prepared from the pulverized coal is avoided; wet powdered coal is sent into a pulping unit for pulping to obtain coal water slurry, so that low-cost but poor-quality raw coal and/or low-cost solid waste can be processed in multiple steps to obtain the coal water slurry conforming to technical parameters, the selection range of raw materials in the coal water slurry gasification process is widened, and the cost of the coal water slurry gasification process is reduced.

Description

Raw material pretreatment method and pretreatment system for entrained flow gasifier

Technical Field

The disclosure relates to the technical field of coal chemical industry, in particular to a raw material pretreatment method and a pretreatment system for an entrained flow gasifier.

Background

The development of high efficiency, cleanness, economy and safety innovation of the continuous pushing coal gasification technology is the key for realizing energy conservation and consumption reduction of coal chemical engineering projects. As an advanced and mature coal gasification technology, the water-coal-slurry gasification technology has the advantages of high gasification pressure, good matching with downstream purification synthesis, safe and reliable coal-slurry preparation, good conveying stability, low device investment and the like, and is widely applied to the fields of coal-to-methanol/olefin/glycol/synthetic ammonia/coal hydrogen production and the like. However, the technical development also has the problems of limited coal selection, difficult coal slurry concentration, low energy efficiency, high carbon emission and the like, and particularly has the advantages of coal slurry concentration and rheological control of coal water slurry, which are closely related to the technical and economic indexes of the whole process.

The gasification of the water-coal-slurry needs to use a gasification furnace, the gasification furnace can carry out both the water-coal-slurry gasification process and the powder slurry gasification process, wherein the powder slurry is formed by mixing the water-coal-slurry and the coal powder, and the gasification effect of the components of the water-coal-slurry in the powder slurry has great influence on the powder slurry gasification when the powder slurry is gasified, so that the gasification furnace needs to use the water-coal-slurry with the coal-slurry concentration and the slurry rheological property reaching standards for ensuring the stable operation of the gasification furnace no matter when the gasification furnace is used, the raw material selection control is a key factor influencing the slurry formation of the water-coal-slurry, the coal-slurry manufactured by using the high-rank coal can reach the standard, but the cost of the high-rank coal is high, the water content of the low-cost inferior coal has high ash content, the slurry formation is poor, the water-coal-slurry which can hardly reach the use standard of the gasification furnace is difficult, the implementation cost of the water-coal-slurry gasification is high, and the practical use and development of the water-coal-slurry gasification are influenced.

Disclosure of Invention

In order to solve the above technical problems or at least partially solve the above technical problems, the present disclosure provides a raw material pretreatment method and a pretreatment system for an entrained flow gasifier.

The disclosure provides a raw material pretreatment method for an entrained flow gasifier, comprising the following steps:

s1: pre-crushing raw material coal and/or solid waste to obtain crushed coal;

s2: sending crushed coal into a pretreatment unit for crushing treatment, dewatering and reducing oxygen-containing functional groups to obtain pulverized coal;

s3: the pulverized coal is sent into a water washing unit to be subjected to water washing treatment, and water-soluble cations in the pulverized coal are removed to obtain wet pulverized coal;

s4: and (3) conveying the wet pulverized coal into a pulping unit for pulping to obtain the coal water slurry.

Optionally, in step S1, the raw material coal includes any one or more combinations of peat, lignite and subbituminous coal, and the solid waste includes any one or more combinations of industrial waste, household waste, fly ash and coke powder in the coal chemical industry park.

Optionally, in step S1, the particle size of the obtained crushed coal is 10mm or less.

Optionally, in step S2, the crushed coal is sent to a pretreatment unit for dewatering, oxygen-containing functional group reduction and crushing treatment, and specifically includes:

S21, delivering crushed coal into a crushed coal mill for crushing, delivering steam-containing hot flue gas generated by a steam superheating mechanism into the crushed coal mill, enabling the steam-containing hot flue gas to be in countercurrent contact with the crushed coal in the crushed coal mill, and performing hydrothermal modification on the crushed coal;

s22, separating the crushed coal subjected to the hydrothermal modification through air separation, returning the crushed coal with the particle size larger than the set particle size to a crushed coal mill for crushing treatment, and enabling the crushed coal with the particle size smaller than or equal to the set particle size to enter a gas-solid separation mechanism under the driving of air flow for gas-solid separation, so as to obtain pulverized coal and steam-containing hot gas.

Optionally, in step S21, the steam introduced by the steam superheating mechanism is steam with preset pressure from a public engineering system, and purge gas and air with set heat values are simultaneously introduced into the steam superheating mechanism, and the introduced steam is preheated through a combustion exothermic reaction, so as to obtain hot flue gas containing steam at 250-400 ℃ with the steam content of more than 40%;

optionally, in step S21, the pressure of the coal pulverizer is 0.1-0.4MPa, and the working temperature of the coal pulverizer is 130-180 ℃;

optionally, in step S22, the method further includes that a part of steam-containing hot gas obtained after the gas-solid separation by the gas-solid separation mechanism is discharged into air, and the other part of steam-containing hot gas enters the steam superheating mechanism for recycling.

Optionally, in step S2, the obtained pulverized coal has an internal water content of less than 5%, an O/C mass ratio of less than 0.2, and a pulverized coal particle having a particle size of 100 μm or less of more than 80%.

Optionally, in step S3, the water containing cations obtained after the water washing treatment is sent to a biochemical treatment unit for wastewater treatment to recover salts.

Optionally, in step S4, the wet pulverized coal is sent to a pulping unit for pulping, which specifically includes:

and feeding wet pulverized coal into a pulping unit, adding water, additives and high-rank coal for the coal water slurry into the pulping unit, and mixing, grinding and pulping in the pulping unit to obtain the coal water slurry with the coal slurry concentration of more than 60%.

The embodiment of the disclosure also provides a raw material pretreatment system for the entrained-flow gasifier, comprising:

the raw material bin is used for storing raw material coal and/or solid waste;

the pre-crushing unit is connected with the raw material bin and used for pre-crushing the raw material coal and/or the solid waste to obtain crushed coal;

the pretreatment system is connected with the pre-crushing unit and is used for carrying out water removal, oxygen-containing functional group reduction and crushing treatment on the crushed coal to obtain pulverized coal;

the washing unit is connected with the pretreatment unit and is used for washing the pulverized coal to remove water-soluble cations in the pulverized coal so as to obtain wet pulverized coal;

And the pulping unit is connected with the water washing unit and is used for pulping the wet pulverized coal to obtain coal water slurry.

Optionally, the raw material bin comprises a raw coal bin and a solid waste bin, wherein the raw coal bin is used for storing low-rank coal, and the solid waste bin is used for storing solid waste in a coal chemical industry park;

optionally, the pretreatment unit comprises a crushed coal mill, a steam superheating mechanism, a fan and a gas-solid separation mechanism, wherein a working space for accommodating and crushing the crushed coal is arranged in the crushed coal mill, a plurality of connecting channels communicated with the working space are arranged on the crushed coal mill, the steam superheating mechanism, the fan and the gas-solid separation mechanism are respectively communicated with the working space through the connecting channels, the fan is positioned at the bottom of the crushed coal mill, the gas-solid separation mechanism is positioned at the top of the crushed coal mill, the crushed coal mill is used for crushing the fed crushed coal, the steam superheating mechanism is used for introducing steam-containing hot flue gas into the crushed coal mill so as to hydrothermally modify the crushed coal, the fan is used for blowing air to the hydrothermally modified crushed coal so as to separate the crushed coal according to the particle size, and the gas-solid separation mechanism is used for performing gas-solid separation on the crushed coal smaller than the set particle size so as to obtain pulverized coal;

Optionally, the pulping unit includes pulping device, basin, additive groove, coal water slurry groove and high order coal bunker, high order coal bunker with pulping device connects, is used for depositing coal water slurry and uses the high order coal and to carry coal water slurry to use the high order coal in the pulping device, basin, additive groove with the coal water slurry groove all with pulping device connects, basin is used for to pulping device carries water, additive groove is used for to pulping device carries the additive, pulping device is used for accomplishing wet fine coal and water, additive and coal water slurry are used for mixing, pulping, the coal water slurry groove is used for storing the coal water slurry that pulping device made.

Compared with the prior art, the technical scheme provided by the embodiment of the disclosure has the following advantages:

the raw material pretreatment method for the entrained-flow gasifier comprises the steps of pre-crushing raw material coal and/or solid waste to obtain crushed coal, and improving the surface areas of the raw material coal and the solid waste, so that the subsequent treatment operation is facilitated; the crushed coal is sent to a pretreatment unit for crushing treatment, water removal and oxygen-containing functional group reduction, so that pulverized coal is obtained, the pretreatment unit reduces the water content of the pulverized coal, reduces the oxygen consumption of the pulverized coal and reduces the oxygen-containing functional group, thereby improving the hydrophobicity of the pulverized coal and enabling the water-coal slurry prepared from the pulverized coal to have good slurry forming property; the pulverized coal is sent into a water washing unit to be subjected to water washing treatment, water-soluble cations in the pulverized coal are removed, wet pulverized coal is obtained, the content of the water-soluble cations in the wet pulverized coal is reduced, and the influence of the water-soluble cations on the repulsive force among coal particles is avoided, so that the fluidity of the coal water slurry prepared from the pulverized coal is reduced; and (3) sending wet pulverized coal into a pulping unit for pulping to obtain coal water slurry, and finally, after the low-quality coal with high moisture content and high ash content is treated by a raw material pretreatment method, obtaining the coal water slurry raw material meeting the technical requirements of coal water slurry gasification, so that the prepared coal water slurry reaches the application standard of coal water slurry gasification or slurry gasification, the selection range of the raw material of the coal water slurry gasification process or slurry gasification process is widened, and the cost of the coal water slurry gasification process or slurry gasification process is reduced.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the disclosure and together with the description, serve to explain the principles of the disclosure.

In order to more clearly illustrate the embodiments of the present disclosure or the solutions in the prior art, the drawings that are required for the description of the embodiments or the prior art will be briefly described below, and it will be obvious to those skilled in the art that other drawings can be obtained from these drawings without inventive effort.

Fig. 1 is a step diagram of a raw material pretreatment method for an entrained-flow gasifier according to an embodiment of the present disclosure.

Fig. 2 is a schematic block diagram of a raw material pretreatment system for an entrained-flow gasifier according to an embodiment of the disclosure.

FIG. 3 is a schematic diagram of a second embodiment of a system for pretreating raw materials for entrained-flow gasifier according to the present disclosure.

Wherein, 1, raw material bin; 11. raw coal bin; 12. a solid waste bin; 2. a pre-crushing unit; 21. a coal crushing bin; 3. a preprocessing unit; 31. crushing coal mill; 32. a blower; 33. a gas-solid separation mechanism; 34. a steam superheating mechanism; 4. a water washing unit; 5. a pulping unit; 51. a pulping device; 52. a water tank; 53. an additive tank; 54. a high-order coal bin; 55. a water-coal slurry tank.

Detailed Description

In order that the above objects, features and advantages of the present disclosure may be more clearly understood, a further description of aspects of the present disclosure will be provided below. It should be noted that, without conflict, the embodiments of the present disclosure and features in the embodiments may be combined with each other.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure, but the present disclosure may be practiced otherwise than as described herein; it will be apparent that the embodiments in the specification are only some, but not all, embodiments of the disclosure.

Referring to fig. 1 to 3, an embodiment of the present disclosure provides a raw material pretreatment method for an entrained-flow gasifier, including the steps of: s1: pre-crushing raw material coal and/or solid waste to obtain crushed coal; s2: sending crushed coal into a pretreatment unit 3 for crushing treatment, dewatering and reducing oxygen-containing functional groups to obtain pulverized coal; s3: the pulverized coal is sent into a water washing unit 4 for water washing treatment, and water-soluble cations in the pulverized coal are removed to obtain wet pulverized coal; s4: and sending the wet pulverized coal into a pulping unit 5 for pulping to obtain the coal water slurry.

Specifically, coal is typically divided using coal levels, which is an amount used to describe the degree of coalification during the formation of coal, and both the physical and chemical properties of the coal affect the coal levels. As the degree of coalification increases, the coal evolves in the order lignite, subbituminous coal, bituminous coal, anthracite coal, according to the original peat. The low-rank lignite, subbituminous coal and the like have high water content and low heat value, the combustion efficiency of the low-rank lignite, subbituminous coal and the like as fuel is low, the water content of the high-rank coal is low, the heat value is high, that is, the carbon content of the coal is increased along with the increase of the rank and maturity of the coal, the hydrogen content is reduced, the oxygen content is reduced, and the volatile substances are reduced along with the increase of the maturity of the coal. Generally, the lower the rank of coal, the higher the internal water content, the higher the oxygen-carbon ratio in the coal, the more hydrophilic functional groups, and the greater the pulping difficulty. The inferior coal is also called low-rank coal, the carbonyl and aliphatic carbon of the inferior coal are increased, namely, the oxygen-containing hydrophilic functional group is more, the oxygen-carbon ratio is high, the hydrophilicity of the inferior coal is increased along with the increase of the hydrophilic functional group, the free water is reduced, the viscosity of the coal slurry prepared from the inferior coal is increased, and the slurry forming property is further deteriorated.

The raw material coal can be selected as low-rank coal with low coal quality change degree, the storage amount of the low-rank coal is large, the price is low, and the solid waste can be selected as solid matters capable of being combusted, such as solid waste in a coal chemical industry park, for example, industrial waste, household waste, fly ash and coke powder; the raw material coal and the solid waste can be put into a coal crusher with rotary vanes, so that the rotary vanes continuously impact the raw material coal and the solid waste to perform pre-crushing treatment, and a vibration structure capable of reciprocating in the coal crusher can be selected, the raw material coal and the solid waste are subjected to vibration to crush the raw material coal and the solid waste, and crushed coal obtained by the pre-crushing treatment is in a block shape or a granular shape; the crushed coal may be obtained by pre-crushing raw material coal, or may be obtained by pre-crushing solid waste, or may be obtained by pre-crushing a mixture of raw material coal and solid waste, or may be obtained by pre-crushing solid waste.

The pretreatment unit 3 can be selected to comprise a coal crusher, and crushed coal enters the coal crusher to be further crushed into coal blocks with smaller particle size to finish crushing treatment, so that the particle size of the crushed coal is reduced, and water removal and oxygen-containing functional group reduction are facilitated; the oxygen-containing functional groups of the crushed coal can be reduced, hot flue gas consisting of purge gas and steam can be selectively introduced into the crushed coal, after the hot flue gas contacts the crushed coal, the oxygen-containing functional groups on the surface of the coal react with water to decompose, and the micropore structures in the coal shrink and collapse, so that the water in the coal is irreversibly removed, the oxygen-containing functional groups are reduced, and the water content of the crushed coal is reduced; the more oxygen-containing functional groups on the surface of coal are, the stronger the hydrophilicity of the coal is, when the coal water slurry is manufactured, a large amount of water molecules are adsorbed on the surface of the coal, the inherent moisture content of the coal is increased, a firm hydration film is formed on the surface of the coal particles by the inherent moisture of the coal, the free flowing water quantity is reduced, the fluidity of the coal water slurry is reduced, the particle size of crushed coal is further reduced after the coal water slurry is treated by the pretreatment unit 3, so that the pulverized coal is formed, the subsequent manufacture of the coal water slurry is easy, the water content in the pulverized coal is reduced, the oxygen-containing functional groups are reduced, the hydrophobicity of the pulverized coal is improved, and the slurry forming property of the pulverized coal is improved.

The washing unit 4 may be selected to have a washing tank in which pulverized coal is placed, and the pulverized coal is placed in the washing tank and washed with water, so that water-soluble cations in the pulverized coal are dissolved in water to reduce the content of water-soluble cations in the pulverized coal, and the pulverized coal after washing carries a part of water to form wet pulverized coal; the positive ions on the surface of the coal can reduce the negative ion potential on the surface of the coal particles, so that the repulsive force effect among the solid particles is reduced, the viscosity of the prepared coal water slurry is increased, and the fluidity of the coal water slurry is affected.

The pulping unit 5 can be selected as a container with a stirrer for holding wet pulverized coal, the wet pulverized coal is placed in the container, water and additives are added into the container, and the wet pulverized coal, the additives and the water are uniformly mixed under the action of the stirrer to form the water-coal slurry.

According to the raw material pretreatment method for the entrained-flow gasifier, in the specific implementation, the raw material pretreatment method comprises the steps of providing a warehouse for storing raw material coal and solid waste, transferring the raw material coal and the solid waste in the warehouse into a coal crusher through a conveyor belt or a transfer vehicle to pretreal the raw material coal and the solid waste to obtain crushed coal, and carrying out water removal, oxygen-containing functional group reduction and crushing treatment on the crushed coal by a pretreatment unit 3 to obtain pulverized coal; after the pulverized coal is treated by a water washing unit 4, water-soluble cations in the pulverized coal are removed, so that wet pulverized coal is obtained, and the wet pulverized coal is sent to a pulping unit 5 to prepare the coal water slurry.

A typical coal type of Xinjiang is selected as raw material coal of a raw material pretreatment method for an entrained-flow gasifier, and the coal quality of the coal type is analyzed as follows:

the coal slurry concentration and fluidity indexes obtained by detection before the coal is treated by the raw material pretreatment method for the entrained-flow gasifier are as follows:

after the coal is treated by the raw material pretreatment method for the entrained-flow gasifier, the coal slurry concentration and fluidity indexes are as follows:

the oxygen-carbon ratio can be obtained by detecting by using an elemental analysis method of national standard GB47691 coal, and the apparent viscosity can be obtained by using the 4 th part of the test method of the national standard GBT 18856.4-2008 coal water slurry: the apparent viscosity is measured and detected, the 24h water separation rate can be selected as the water coal slurry is closed and kept stand for 24 hours, then the weight of water separated out from the water coal slurry is detected, and the ratio of the weight of water separated out from the water coal slurry in the total weight of the water coal slurry subjected to standing is 24h water separation rate; the fluidity can be selected by taking a funnel with the aperture of 16mm, flowing the water-coal-slurry from the funnel, observing the flowing state of the water-coal-slurry passing through the funnel, and judging the fluidity of the water-coal-slurry; the stability can be selected as the water-coal-slurry sealing and standing for 24 hours, observing the sediment generated after standing, and judging the hardness of the sediment.

The coal type before raw material pretreatment and the coal type after raw material pretreatment are adopted to carry out gasification reaction, in the gasification reaction process, the operation pressure of the entrained flow gasifier is controlled to be 4MPa, the temperature is controlled to be 1350 ℃, and specific indexes obtained by detection are compared with indexes before and after the treatment of the raw material pretreatment method for the entrained flow gasifier:

after the coal is treated by the raw material pretreatment method for the entrained-flow gasifier, the slurry concentration and the flow characteristic of the prepared coal water slurry are improved, the effective gas yield is improved, the oxygen consumption of coal is reduced, the effective gas quantity is improved and the oxygen consumption of coal is reduced under the same coal feeding quantity, the energy conversion efficiency is improved, and the implementation cost of the coal water slurry gasification process can be reduced, so that the technical and economic indexes are improved.

The raw material pretreatment method for the entrained-flow gasifier comprises the steps of carrying out pretreatment on raw material coal and/or solid waste to obtain crushed coal, and improving the surface area of the raw material coal and the solid waste so as to facilitate the subsequent treatment operation; the crushed coal is sent to a pretreatment unit 3 for crushing treatment, water removal and oxygen-containing functional group reduction, so as to obtain pulverized coal, the pretreatment unit 3 reduces the water content of the pulverized coal, reduces the oxygen consumption of the pulverized coal and reduces the oxygen-containing functional group, thereby improving the hydrophobicity of the pulverized coal and enabling the water-coal slurry prepared from the pulverized coal to have good slurry forming property; the pulverized coal is sent into a water washing unit 4 to be subjected to water washing treatment, water-soluble cations in the pulverized coal are removed, wet pulverized coal is obtained, the content of the water-soluble cations in the wet pulverized coal is reduced, and the influence of the water-soluble cations on the repulsive force among coal particles is avoided, so that the fluidity of the coal water slurry prepared from the pulverized coal is reduced; the wet pulverized coal is sent into a pulping unit 5 for pulping, so as to obtain the water-coal-slurry, and finally, the low-rank coal with high water content and high ash content is treated by a raw material pretreatment method to obtain the water-coal-slurry raw material meeting the technical requirements of the water-coal-slurry gasification, so that the prepared water-coal-slurry meets the application standard of the water-coal-slurry gasification or the powder-slurry gasification, the selection range of the raw material of the water-coal-slurry gasification process or the powder-slurry gasification process is widened, and the cost of the water-coal-slurry gasification process or the powder-slurry gasification process is reduced.

Referring to fig. 1 to 3, in some embodiments, in step S1, the raw coal includes any one or more combinations of peat, lignite, and subbituminous coal, and the solid waste includes any one or more combinations of industrial waste, household waste, fly ash, and coke breeze of the coal chemical industry park.

Specifically, raw material coal can be selected as peat or lignite, or subbituminous coal can be selected, as long as the raw material coal is low-priced low-grade coal or low-rank coal, industrial waste, household garbage, fly ash and coke powder in a coal chemical industry park are all combustible as solid wastes, the raw material coal can be used as fuel for combustion, and the raw material coal can be mixed with the low-rank coal to further reduce the raw material cost for preparing the water-coal slurry later, or the solid wastes are pre-crushed to form blocky combustible solids to be used as crushed coal. The raw material coal and the solid waste can be mixed and then subjected to the pre-crushing treatment, or the raw material coal and the solid waste can be subjected to the pre-crushing treatment, and the raw material coal, the solid waste or the mixture of the raw material coal and the solid waste can be determined according to the actual conditions in industrial production.

By setting the raw material coal to be any one or a plurality of combinations of peat, lignite and subbituminous coal, and the solid waste to be any one or a plurality of combinations of industrial waste, household waste, fly ash and coke powder in a coal chemical industry park, the raw material coal is a mixture of low-rank coal with low price and the solid waste, so that the raw material cost for preparing the coal water slurry is reduced, the solid waste is mixed with the raw material coal, and the raw material cost for preparing the coal water slurry is further reduced while the waste is utilized.

Referring to fig. 1 to 3, in some embodiments, the particle size of the obtained crushed coal is 10mm or less in step S1.

Specifically, the raw material coal and the solid waste can be selected to be subjected to pre-crushing treatment together, or only the raw material coal is subjected to pre-crushing treatment, the maximum particle size of the obtained particles is less than 10mm, the contact area of the raw material coal is increased by the pre-crushing treatment, and the raw material coal is convenient to prepare into powdered coal after being crushed.

Through setting up in step S1, the particle diameter of the crushed coal that obtains is below 10mm, makes the raw materials coal that original volume is great broken into the granule, has increased raw materials coal' S surface area, promotes follow-up dewatering, falls the efficiency of oxygen functional group to the granule below 10mm is broken in advance, can reduce the time of the crushing processing in step S2, makes the crushed coal can make into fine coal more soon.

Referring to fig. 1 to 3, in some embodiments, in step S2, crushed coal is sent to the pretreatment unit 3 to perform water removal, oxygen-containing functional group reduction, and crushing treatment, specifically including: s21, delivering crushed coal into a crushed coal mill 31 for crushing, delivering steam-containing hot flue gas generated by a steam superheating mechanism 34 into the crushed coal mill 31, enabling the steam-containing hot flue gas to be in countercurrent contact with the crushed coal in the crushed coal mill 31, and performing hydrothermal modification on the crushed coal; s22, separating the crushed coal subjected to the hydrothermal modification through air separation, returning the crushed coal with the particle size larger than the set particle size to a crushed coal mill 31 for crushing treatment, and enabling the crushed coal with the particle size smaller than or equal to the set particle size to enter a gas-solid separation mechanism 33 for gas-solid separation under the driving of air flow, so as to obtain pulverized coal and steam-containing hot gas.

Specifically, the crushed coal mill 31 may be a mill having a millstone structure, and the crushed coal is changed into powder from block particles under the action of the millstone; the steam superheating mechanism 34 may optionally include a gas mixing section into which purge gas, steam and air are introduced, and a heating section for heating the gas in the gas mixing section to obtain steam-containing hot flue gas, and may optionally include a steam content of 40% or more in the steam-containing hot flue gas, and a temperature of 250 ℃ to 400 ℃. The crushed coal moves in one direction in the crushed coal mill 31, the steam-containing hot flue gas is introduced into the crushed coal mill 31, and the moving direction of the steam-containing hot flue gas in the crushed coal mill 31 is opposite to the moving direction of the crushed coal, so that countercurrent contact between the steam-containing hot flue gas and the crushed coal in the crushed coal mill 31 is realized, and the steam-containing hot flue gas and the crushed coal are fully contacted, so that the steam-containing hot flue gas and the crushed coal are fully subjected to hydrothermal modification reaction.

The hydrothermal modification reaction is that high-temperature water vapor reacts with oxygen-containing functional groups on the surface of crushed coal, so that the number of the oxygen-containing functional groups of the crushed coal is reduced, the micropore structure inside the crushed coal is contracted and collapsed by high-temperature hot flue gas, the water content in the crushed coal is reduced, the particle size of particles of the crushed coal is further reduced by crushing treatment, the contact area between the crushed coal and steam-containing hot flue gas is increased by further crushing of the crushed coal, the reaction efficiency of hydrothermal modification is improved, the crushed formed pulverized coal is convenient for subsequent preparation of water-coal slurry, and the high-temperature steam-containing hot flue gas can also dry the coal particles in a crushed coal mill.

The above-mentioned winnowing is that after the crushed coal crushed into powder in the crushed coal mill 31 is hydrothermally modified for a set time, the crushed coal with the diameter smaller than or equal to the set particle diameter is blown by the fan 32 to enter the gas-solid separation mechanism 33 under the driving of the air flow, the direction of the wind field formed by the fan 32 can be selected to be upward, or the wind field formed by the fan 32 can be selected to be blown obliquely upward, and the fan 32 is blown towards the gas-solid separation mechanism 33; the crushed coal crushed into powder passes through a wind field, the crushed coal crushed into powder with the diameter smaller than or equal to the set particle size has lighter mass, the wind field can bring the crushed coal into the gas-solid separation mechanism 33, the particles with the diameter larger than the set particle size have heavier mass, and the wind field can not blow the particles, so that the particles fall back to the crushed coal mill 31 for continuous crushing; the set time may be selected to be 30 minutes, or may be selected to be 1 hour, or may be selected to be other time length, and the time length of the set time is determined according to different coal types and processes.

The gas-solid separation mechanism 33 may be a cloth bag with pores, the diameter of the pores is smaller than the set particle diameter, crushed coal and steam-containing hot flue gas which are crushed into powder enter the cloth bag, the steam-containing hot flue gas passes through the pores and is discharged out of the cloth bag, and the crushed coal which is crushed into powder is left in the cloth bag to form pulverized coal.

By setting in step S2, crushed coal is sent to the pretreatment unit 3 for dewatering, oxygen-containing functional group reduction and crushing treatment, and specifically comprises: s21, delivering crushed coal into a crushed coal mill 31 for crushing, delivering steam-containing hot flue gas generated by a steam superheating mechanism 34 into the crushed coal mill 31, enabling the steam-containing hot flue gas to be in countercurrent contact with the crushed coal in the crushed coal mill 31, and performing hydrothermal modification on the crushed coal; s22, separating the crushed coal subjected to the hydrothermal modification through air separation, returning the crushed coal with the particle size larger than the set particle size into a crushed coal mill 31 for crushing treatment, and enabling the crushed coal with the particle size smaller than or equal to the set particle size to enter a gas-solid separation mechanism 33 for gas-solid separation under the drive of air flow to obtain pulverized coal and steam-containing hot gas, and finally enabling steam-containing hot flue gas to be in countercurrent contact with the crushed coal, so that the steam-containing hot flue gas is fully contacted with the crushed coal to fully perform hydrothermal reaction, and further crushing the crushed coal in the crushed coal mill 31 improves the contact area of the crushed coal and the steam-containing hot flue gas, thereby improving the efficiency of the hydrothermal reaction; the air separation can conveniently send the crushed coal meeting the particle size requirement into the gas-solid separation mechanism 33, so that the efficiency of treating the crushed coal in the pretreatment unit 3 is improved.

Referring to fig. 1 to 3, in some embodiments, in step S21, the steam introduced into the steam superheating mechanism 34 is steam of a preset pressure from a utility system, purge gas and air of a set heating value are simultaneously introduced into the steam superheating mechanism 34, and the introduced steam is preheated by a combustion exothermic reaction, so as to obtain hot flue gas containing steam at 250-400 ℃ with a steam content of 40% or more.

Specifically, a steam pipeline provided by a public engineering system for engineering or industrial park can be selected, and purge gas is a material name in chemical production. In many chemical processes, in order to maintain balance, high efficiency, normal and stable operation of chemical reactions, the gas generated by side reactions in the chemical process or the residual components of the raw materials of the mixed gas are often discharged continuously or periodically from the production device, and the gas is called purge gas. The set heat value of the purge gas is determined according to the difference in the components of the purge gas.

The preset pressure can be selected to be 0.5MPa or 0.2MPa, the public engineering system can only provide water vapor with stable pressure value according to design, the pressure value is the preset pressure, the preset pressure can be selected to be 0.2MPa, 0.5MPa or 1.2MPa, the water vapor with other pressure values can be provided according to different practical conditions of the public engineering system, and the water vapor with the preset pressure can be provided by the steam superheating mechanism only by directly connecting the water vapor with the preset pressure provided by the public engineering system, so that the existing factory steam setting can be utilized, and the boiler is not required to be independently arranged to provide water vapor.

The steam overheated mechanism 34 is arranged in the step S21, the steam with preset pressure is supplied to the common engineering system, purge gas with preset heat value and air are supplied to the steam overheated mechanism 34, the supplied steam is preheated through combustion exothermic reaction, so that the 250-400 ℃ steam-containing hot flue gas with the steam content of more than 40% is obtained, the mixing of the purge gas and the steam is utilized, the cost for manufacturing the hot flue gas is reduced, the steam-containing hot flue gas is between 250 ℃ and 400 ℃, the steam in the hot flue gas can react with oxygen-containing functional groups in coal at the temperature, the oxygen-containing functional groups are decomposed, the steam content is more than 40%, the hot flue gas can fully react with the oxygen-containing functional groups in crushed coal, and the effect of the hot flue gas on removing the oxygen-containing functional groups in the crushed coal is ensured.

Referring to fig. 1 to 3, in some embodiments, in step S21, the pressure of the crushed coal mill 31 is 0.1 to 0.4MPa, specifically, may be 0.1MPa, 0.2MPa, 0.3MPa, 0.4MPa, etc., and the operating temperature of the crushed coal mill 31 is 130 to 180 ℃, specifically, may be 130 ℃, 150 ℃, 180 ℃, etc.

Specifically, the pressure of the coal pulverizer 31 is the pressure applied to the pulverized coal pieces in the coal pulverizer 31 when the coal pulverizer 31 is in operation, the set pressure can be selected to be 0.2MPa, or the set pressure can be selected to be 0.4MPa, the pressure of the coal pulverizer 31 is related to the model and the power of the coal pulverizer 31, the set pressures with different values are different according to the model and the power of the selected coal pulverizer 31, the operating temperature of the coal pulverizer 31 is the temperature of the whole coal pulverizer 31 when in operation, and the operating temperature of the coal pulverizer 31 is 130 ℃ to 180 ℃.

By setting the pressure of the crushed coal mill 31 in the step S21 to be 0.1-0.4MPa and the working temperature of the crushed coal mill 31 to be 130-180 ℃, the crushed coal mill 31 is ensured to sufficiently crush the crushed coal further, the speed of heat dissipation when steam-containing hot flue gas reacts in the crushed coal mill 31 is reduced, and the hydrothermal modification reaction is ensured to be carried out smoothly.

Referring to fig. 1 to 3, in some embodiments, step S22 further includes, after the gas-solid separation by the gas-solid separation mechanism 33, a steam-containing hot gas, a part of which is exhausted into air, and another part of which enters the steam superheating mechanism 34 for recycling.

Specifically, the steam-containing hot flue gas and crushed coal subjected to crushing treatment are subjected to hydrothermal modification reaction in the crushed coal mill 31, so that part of purge gas in the steam-containing hot flue gas is reacted with crushed coal subjected to crushing treatment to be consumed, the steam-containing hot flue gas is changed into steam-containing hot gas, crushed coal subjected to crushing treatment and subjected to hydrothermal modification reaction is blown into the gas-solid separation mechanism 33 together with the steam-containing hot gas in the air separation process, the gas-solid separation mechanism 33 is connected with the steam superheating mechanism 34 through an air duct, the separated gas-solid separation mechanism 33 is used for separating the air-separated crushed coal, the steam-containing hot gas is discharged into the steam superheating mechanism 34 for recycling, and part of steam-containing hot gas can be scattered in the air.

The step S22 further comprises that a part of the steam-containing hot flue gas obtained after the gas-solid separation by the gas-solid separation mechanism 33 is discharged into the air, and the other part of the steam-containing hot flue gas enters the steam superheating mechanism 34 for recycling, so that the steam-containing hot flue gas with a certain temperature can be returned to the steam superheating mechanism 34 for recycling after being separated from the crushed coal subjected to air separation by the gas-solid separation mechanism 33, and the energy consumption required for keeping the temperature of the steam-containing hot flue gas is reduced.

Referring to fig. 1 to 3, in some embodiments, in step S2, the obtained pulverized coal has an internal water content of less than 5%, an O/C mass ratio of less than 0.2, and pulverized coal particles having a particle size of 100 μm or less account for more than 80%.

Specifically, when the crushed coal crushed into powder is selected to be winnowed, as the crushed coal is driven by a mill to continuously move, the crushed coal particles with the particle size larger than the set particle size possibly enter the gas-solid separation mechanism 33 under the action of kinetic energy, so that the requirement of the pulverized coal can be met only by the pulverized coal particles with the particle size smaller than 100 mu m with the particle size of more than 80%, the pulverized coal particles with the particle size smaller than 100 mu m can be conveniently and subsequently mixed with water to prepare the coal water slurry, the internal water content of the pulverized coal is smaller than 5%, the fluidity of the coal water slurry prepared by the pulverized coal is ensured, the O/C mass ratio is smaller than 0.2, and the oxygen-containing functional groups in the pulverized coal are less, so that the coal water slurry prepared by the pulverized coal has better slurry forming property.

The internal water content of the obtained pulverized coal is less than 5%, the O/C mass ratio is less than 0.2, and the pulverized coal particle ratio of the pulverized coal particles with the particle diameter of less than 100 μm is more than 80% by setting in the step S2, so that the physical property of the treated pulverized coal is suitable for preparing the water-coal-slurry with good slurry property.

Referring to fig. 1 to 3, in some embodiments, the step S3 further includes feeding the water containing the cations obtained after the water washing treatment into a biochemical treatment unit for wastewater treatment to recover salts.

Specifically, the water containing cations generally has metal cations of higher value metals, and the biochemical treatment unit can prepare salt compounds from cations dissolved in the water after the water washing treatment.

The step S3 further comprises the step of sending the water containing cations obtained after the water washing treatment into a biochemical treatment unit for wastewater treatment so as to recover salts, thereby improving the utilization rate of raw materials, increasing the types of products with economic value produced by the raw material pretreatment system for the entrained flow gasifier and improving the economic benefit.

Referring to fig. 1 to 3, in some embodiments, in step S4, wet pulverized coal is fed into a pulping unit 5 for pulping, specifically including: the wet pulverized coal is sent into a pulping unit 5, water, additives and high-rank coal for the coal water slurry are added into the pulping unit 5, and the mixture, grinding and pulping are carried out in the pulping unit 5, so that the coal water slurry with the concentration of the coal slurry being more than 60% is obtained.

Specifically, the pulping unit 5 at least comprises a pulping tank for stirring and mixing, and the wet pulverized coal, water, additives and a part of high-rank coal for the water-coal-slurry are placed into the pulping tank for complete mixing to prepare the water-coal-slurry, wherein the high-rank coal for the water-coal-slurry is powdery coal with small oxygen content and low internal water content.

By being set in step S4, the wet fine coal is fed into the pulping unit 5 for pulping, specifically comprising: the wet pulverized coal is sent into a pulping unit 5, water, an additive and high-rank coal for the water-coal-slurry are added into the pulping unit 5, the mixture is mixed in the pulping unit 5, grinding and pulping are carried out, the water-coal-slurry with the concentration of the coal-slurry being more than 60% is obtained, and finally the wet pulverized coal is fully mixed with the water, the additive and the high-rank coal for the water-coal-slurry in the pulping unit 5, so that the water-coal-slurry is obtained.

Referring to fig. 1 to 3, the embodiment of the present disclosure further provides a raw material pretreatment system for an entrained-flow gasifier, including a raw material bin 1 for storing raw material coal and/or solid waste;

the pre-crushing unit 2 is connected with the raw material bin 1 and is used for carrying out pre-crushing treatment on raw material coal and/or solid waste to obtain crushed coal;

the pretreatment unit 3 is connected with the pre-crushing unit 2 and is used for carrying out water removal, oxygen-containing functional group reduction and crushing treatment on crushed coal to obtain pulverized coal;

The washing unit 4 is connected with the pretreatment unit 3 and is used for washing the pulverized coal to remove water-soluble cations in the pulverized coal so as to obtain wet pulverized coal;

and the pulping unit 5 is connected with the water washing unit 4 and is used for pulping wet pulverized coal to obtain coal water slurry.

Specifically, the pre-crushing unit 2 may include a coal crusher, the coal crusher may have a rotary blade, and the rotary blade is used to collide with raw coal, so as to crush the raw coal, or of course, the coal crusher may also have a vibration device, and the raw coal vibrates in the vibration device, so that the raw coal is crushed to complete the pre-crushing treatment, the pre-crushing unit 2 may further include a coal crushing bin 21, the crushed coal after the pre-crushing treatment is stored in the coal crushing bin 21, and the coal crushing bin 21 is connected with the subsequent pre-treatment unit 3 through a conveying belt; the raw material bin 1 can be connected with the pre-crushing unit 2 by using a conveyer belt, and can be connected with the pre-crushing unit 2 by using a conveyer pipe.

The pretreatment unit 3 described above includes a crushed coal mill 31 having a grinding table or a grinding roller for crushing crushed coal, and a ventilation device for introducing a gas for performing hydrothermal modification into the mill; the washing unit 4 is connected with the pretreatment unit 3 through a conveyor belt or a conveying pipe, the pulping unit 5 is arranged at the downstream of the washing unit 4, the pulping unit 5 can be provided with a groove body for containing wet pulverized coal, the groove body can be arranged at the downstream of the washing unit 4, and the wet pulverized coal after washing can enter the pulping unit 5 after being separated from the washing unit 4.

The raw material bin 1 is used for storing raw material coal and/or solid waste, so that foreign matter pollution is avoided; the pre-crushing unit 2 is connected with the raw material bin 1 and is used for pre-crushing raw material coal and/or solid waste to obtain crushed coal, pre-crushing larger raw materials to reduce the particle size of the raw materials and facilitate the subsequent acquisition of pulverized coal suitable for making coal water slurry; the pretreatment unit 3 is connected with the pre-crushing unit 2 and is used for carrying out water removal, oxygen-containing functional group reduction and crushing treatment on crushed coal to obtain pulverized coal, the oxygen-containing functional group of the pulverized coal is reduced, the hydrophobicity of the pulverized coal is improved, and therefore the pulverized coal has good slurrying performance; the washing unit 4 is connected with the pretreatment unit 3 and is used for washing the pulverized coal to remove water-soluble cations in the pulverized coal so as to obtain wet pulverized coal; the pulping unit 5 is connected with the water washing unit 4 and is used for pulping wet pulverized coal to obtain coal water slurry, and finally the raw material bin 1, the pre-crushing unit 2, the pre-treatment unit 3, the water washing unit 4 and the pulping unit 5 are mutually connected to form an integral system, and the pretreatment work of raw materials for the entrained-flow gasifier is efficiently completed through mutual cooperation.

Referring to fig. 1 to 3, in some embodiments, the raw coal bin 1 includes a raw coal bin 11 for storing low rank coal and a solid waste bin 12 for storing solid waste from a coal chemical industry park.

Specifically, the raw coal bin 11 and the solid waste bin 12 may be selected to be connected with the pre-crushing unit 2 through a conveying belt, and of course, the raw coal bin 11 and the solid waste bin 12 may also be selected to be connected with the pre-crushing unit 2 through conveying pipes.

Through setting up former feed bin 1 and including former coal bunker 11 and solid useless storehouse 12, former coal bunker 11 is used for depositing low order coal, and solid useless storehouse 12 is used for depositing the solid waste in coal industry garden to make low order coal and solid useless storehouse 12 deposit respectively, be convenient for manage.

Referring to fig. 1 to 3, in some embodiments, the pretreatment unit 3 includes a crushed coal mill 31, a steam superheating mechanism 34, a fan 32, and a gas-solid separation mechanism 33, a working space for accommodating and crushing crushed coal is provided inside the crushed coal mill 31, a plurality of connection passages communicating with the working space are provided on the crushed coal mill 31, the steam superheating mechanism 34, the fan 32, and the gas-solid separation mechanism 33 communicate with the working space through the connection passages, respectively, the fan is located at the bottom of the crushed coal mill 31, the gas-solid separation mechanism 33 is located at the top of the crushed coal mill 31, the crushed coal mill 31 is used for crushing the fed crushed coal, the steam superheating mechanism 34 is used for introducing steam-containing hot flue gas into the crushed coal mill 31 to hydrothermally modify the crushed coal, the fan 32 is used for blowing the hydrothermally modified crushed coal to separate the crushed coal according to the particle size, and the gas-solid separation mechanism 33 is used for performing gas-solid separation of crushed coal smaller than the set particle size to obtain the crushed coal.

Specifically, the coal crushing mill 31 may be selected to include a coal crushing mill and a coal crushing roller, a cavity is provided in the coal crushing mill 31 as a working space, the coal crushing mill and the coal crushing roller are disposed in the cavity, three through holes are provided on the surface of the coal crushing mill 31 as connecting channels, the steam superheating mechanism 34, the fan 32 and the gas-solid separation mechanism 33 are connected in one-to-one correspondence with the three through holes, so as to communicate with the cavity, the gas-solid separation mechanism 33 is connected with the cavity and the steam superheating mechanism 34, the steam superheating mechanism 34 includes a mixing cavity for mixed gas and a heating part, and the heating part is used for heating the mixing cavity; the fan 32 is arranged below the gas-solid separation mechanism 33, and the fan 32 blows air towards the communication port between the gas-solid separation mechanism 33 and the cavity, so that the wind field generated by the fan 32 is utilized to carry out winnowing on crushed coal particles with different particle sizes; the gas-solid separation mechanism 33 includes at least a filtering mechanism that allows only gas to pass therethrough, so that the gas-solid separation mechanism 33 can separate crushed coal from hot flue gas containing steam.

By providing the pretreatment unit 3 comprising a crushed coal mill 31, a steam superheating mechanism 34, a fan 32 and a gas-solid separation mechanism 33, the steam superheating mechanism 34, the fan 32 and the gas-solid separation mechanism 33 are communicated with the inside of the crushed coal mill 31 so as to further crush crushed coal in the inside of the crushed coal mill, the steam superheating mechanism 34 is used for performing hydrothermal modification, and the fan 32 is used for performing air separation; the crushed coal mill 31 is used for crushing the fed crushed coal, the steam superheating mechanism 34 is used for introducing steam-containing hot flue gas into the crushed coal mill 31 so as to hydrothermally modify the crushed coal, the fan 32 is used for blowing air to the hydrothermally modified crushed coal so as to separate the crushed coal according to the particle size, the gas-solid separation mechanism 33 is used for carrying out gas-solid separation on the crushed coal smaller than the set particle size so as to obtain pulverized coal, and finally the crushed coal mill 31, the steam superheating mechanism 34, the fan 32 and the gas-solid separation mechanism 33 are mutually matched to finish the further crushing, hydrothermal modification and air separation operations of the crushed coal.

Referring to fig. 2 and 3, in some embodiments, the pulping unit 5 includes a pulping device 51, a water tank 52, an additive tank 53, a water-coal-slurry tank 55, and a high-rank coal bin 54, the high-rank coal bin 54 is connected to the pulping device 51, the high-rank coal bin 54 is used for storing high-rank coal for water-coal slurry and delivering the high-rank coal for water-coal slurry into the pulping device 51, the water tank 52, the additive tank 53, and the water-coal-slurry tank 55 are connected to the pulping device 51, the water tank 52 is used for delivering water to the pulping device 51, the additive tank 53 is used for delivering the additive to the pulping device 51, the pulping device 51 is used for completing mixing of wet pulverized coal with water, the additive, and the high-rank coal for water-coal slurry, and the water-coal-slurry tank 55 is used for storing the water-coal slurry produced by the pulping device 51.

Specifically, the pulping device 51 may be a tank body with a stirrer, the water tank 52 and the adder tank are communicated with the tank body, the high-rank coal bin 54 is connected with the pulping device 51 through a conveying belt, the water washing unit 4 is connected with the pulping device 51, after wet pulverized coal is put into the tank body of the pulping device 51, the water tank 52 adds water into the tank body, the additive tank 53 adds an additive into the tank body, the high-rank coal bin 54 adds high-rank coal into the tank body, the stirrer in the tank body mixes the wet pulverized coal, the water, the additive and the high-rank coal to prepare coal slurry, the coal slurry tank 55 is arranged at the downstream of the pulping device 51, and the coal slurry tank 55 is connected with the pulping device 51, so that the coal slurry in the pulping device 51 can flow into the coal slurry tank 55 for storage.

In the embodiment of the disclosure, raw material coal and solid waste are respectively transported from a raw coal bin 11 and a solid waste bin 12 to a pre-crushing unit 2 for pre-crushing treatment to obtain crushed coal, the crushed coal is stored in a crushed coal bin 21, the crushed coal in the crushed coal bin 21 is transported to a crushed coal mill 31 of a pre-treatment unit 3 for further crushing treatment, a steam superheating mechanism 34 conveys steam-containing hot flue gas to the crushed coal mill 31, the steam-containing hot flue gas and the crushed coal in the crushed coal mill 31 undergo a hydrothermal modification reaction, a fan 32 performs winnowing on the crushed coal in the crushed coal mill 31 after the hydrothermal modification reaction is carried out for a set time, crushed coal particles with particle sizes smaller than or equal to a set particle size are blown to a gas-solid separation mechanism 33, the gas-solid separation mechanism 33 separates the steam-containing hot flue gas and the crushed coal particles subjected to air separation to obtain pulverized coal, a part of the steam-containing flue gas separated by the gas-solid separation mechanism 33 is returned to the steam superheating mechanism 34 for recycling, the pulverized coal is transported to the water washing unit 4 for water washing treatment, water soluble cations in the pulverized coal are removed to obtain wet pulverized coal, water containing cations obtained after the water washing treatment is sent to the biochemical treatment unit for wastewater treatment to recover salts, the wet pulverized coal is sent to the pulping device 51, water, additives and high-order coal are added to the pulping device 51 through the water tank 52, the additive tank 53 and the high-order coal bin 54, the pulping device 51 mixes the wet pulverized coal, the water, the additives and the high-order coal to obtain the coal slurry, and the coal slurry obtained by the pulping device 51 is sent to the coal slurry tank 55 for storage.

It should be noted that in this document, relational terms such as "first" and "second" and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The foregoing is merely a specific embodiment of the disclosure to enable one skilled in the art to understand or practice the disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown and described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. The raw material pretreatment method for the entrained-flow gasifier is characterized by comprising the following steps of:

s1: pre-crushing raw material coal and/or solid waste to obtain crushed coal;

s2: sending crushed coal into a pretreatment unit for crushing treatment, dewatering and reducing oxygen-containing functional groups to obtain pulverized coal;

s3: the pulverized coal is sent into a water washing unit to be subjected to water washing treatment, and water-soluble cations in the pulverized coal are removed to obtain wet pulverized coal;

s4: and (3) conveying the wet pulverized coal into a pulping unit for pulping to obtain the coal water slurry.

2. The method according to claim 1, wherein in step S1, the raw coal includes any one or more of peat, lignite, and subbituminous coal, and the solid waste includes any one or more of industrial waste, household waste, fly ash, and coke powder in a coal chemical industry park.

3. The method for pretreating a raw material for an entrained-flow gasifier according to claim 1, wherein in step S1, the particle size of the obtained crushed coal is 10mm or less.

4. The method for pretreating raw materials for entrained-flow gasifier according to claim 1, wherein in step S2, crushed coal is fed into a pretreatment unit to be subjected to dehydration, oxygen-containing functional group reduction and crushing treatment, specifically comprising:

S21, delivering crushed coal into a crushed coal mill for crushing, delivering steam-containing hot flue gas generated by a steam superheating mechanism into the crushed coal mill, enabling the steam-containing hot flue gas to be in countercurrent contact with the crushed coal in the crushed coal mill, and performing hydrothermal modification on the crushed coal;

s22, separating the crushed coal subjected to the hydrothermal modification through air separation, returning the crushed coal with the particle size larger than the set particle size to a crushed coal mill for crushing treatment, and enabling the crushed coal with the particle size smaller than or equal to the set particle size to enter a gas-solid separation mechanism under the driving of air flow for gas-solid separation, so as to obtain pulverized coal and steam-containing hot gas.

5. The method for pretreating raw materials for entrained-flow gasifier according to claim 4, wherein in step S21, steam introduced into the steam superheating mechanism is steam of a preset pressure from a public engineering system, purge gas and air of a set heating value are simultaneously introduced into the steam superheating mechanism, and the introduced steam is preheated by a combustion exothermic reaction to obtain hot flue gas containing steam at 250-400 ℃ with a steam content of 40% or more;

and/or, in step S21, the pressure of the crushed coal mill is 0.1-0.4MPa, and the working temperature of the crushed coal mill is 130-180 ℃;

And/or, in the step S22, steam-containing hot gas obtained after the gas-solid separation by the gas-solid separation mechanism is partially discharged into air, and the other part enters the steam superheating mechanism for recycling.

6. The method according to claim 1, wherein in step S2, the pulverized coal obtained has an internal water content of less than 5%, an O/C mass ratio of less than 0.2, and pulverized coal particles having a particle size of 100 μm or less account for more than 80%.

7. The method according to claim 1, wherein the step S3 further comprises feeding the water containing the cations obtained after the water washing treatment to a biochemical treatment unit for wastewater treatment to recover salts.

8. The method according to claim 1, wherein in step S4, wet pulverized coal is fed into a pulping unit to be pulped, and the method specifically comprises:

and (3) feeding wet pulverized coal into a pulping unit, adding water, additives and high-rank coal for the water-coal-slurry into the pulping unit, and mixing, grinding and pulping in the pulping unit to obtain the water-coal-slurry with the concentration of more than 60%.

9. A raw material pretreatment system for an entrained flow gasifier, comprising:

The raw material bin is used for storing raw material coal and/or solid waste;

the pre-crushing unit is connected with the raw material bin and used for pre-crushing the raw material coal and/or the solid waste to obtain crushed coal;

the pretreatment unit is connected with the pre-crushing unit and is used for carrying out water removal, oxygen-containing functional group reduction and crushing treatment on the crushed coal to obtain pulverized coal;

the washing unit is connected with the pretreatment unit and is used for washing the pulverized coal to remove water-soluble cations in the pulverized coal so as to obtain wet pulverized coal;

and the pulping unit is connected with the water washing unit and is used for pulping the wet pulverized coal to obtain coal water slurry.

10. The raw material pretreatment system for an entrained-flow gasifier as recited in claim 9, wherein the raw material bin comprises a raw coal bin for storing low-rank coal and a solid waste bin for storing solid waste of a coal chemical industry park;

and/or the pretreatment unit comprises a crushed coal mill, a steam superheating mechanism, a fan and a gas-solid separation mechanism, wherein a working space for accommodating and crushing the crushed coal is arranged in the crushed coal mill, a plurality of connecting channels communicated with the working space are arranged on the crushed coal mill, the steam superheating mechanism, the fan and the gas-solid separation mechanism are respectively communicated with the working space through the connecting channels, the fan is positioned at the bottom of the crushed coal mill, the gas-solid separation mechanism is positioned at the top of the crushed coal mill, the crushed coal mill is used for crushing the fed crushed coal, the steam superheating mechanism is used for introducing steam-containing hot flue gas into the crushed coal mill so as to hydrothermally modify the crushed coal, the fan is used for blowing air to the hydrothermally modified crushed coal so as to separate the crushed coal according to the particle size, and the gas-solid separation mechanism is used for carrying out gas-solid separation on the crushed coal smaller than the set particle size so as to obtain pulverized coal;

And/or, the pulping unit comprises a pulping device, a water tank, an additive tank, a coal water slurry tank and a high-order coal bin, wherein the high-order coal bin is connected with the pulping device and used for storing high-order coal for coal water slurry and conveying the high-order coal for coal water slurry into the pulping device, the water tank, the additive tank and the coal water slurry tank are connected with the pulping device and used for conveying water to the pulping device, the additive tank is used for conveying additives to the pulping device, the pulping device is used for completing mixing and pulping of wet pulverized coal, water, the additives and the high-order coal for coal water slurry, and the coal water slurry tank is used for storing the coal water slurry prepared by the pulping device.