Method for pre-treating feedstock for use in an entrained flow gasifier and pre-treatment system

Abstract

This disclosure relates to the field of coal chemical technology, and provides a raw material pretreatment method and system for a fluidized bed gasifier. The raw material pretreatment method for the fluidized bed gasifier involves pre-crushing the raw coal and / or solid waste to obtain pulverized coal, thereby increasing the contact area; the pulverized coal is then fed into a pretreatment unit for further crushing, water removal, and reduction of oxygen-containing functional groups to obtain pulverized coal, improving its hydrophobicity and giving it good slurry-forming properties; the pulverized coal is then fed into a washing unit for washing to remove water-soluble cations, obtaining wet pulverized coal, thus preventing cations from affecting the flowability of the coal-water slurry produced from the pulverized coal; the wet pulverized coal is then fed into a slurry preparation unit to obtain coal-water slurry. This multi-step treatment process allows for the production of coal-water slurry that meets technical parameters from inexpensive but low-quality raw coal and / or inexpensive solid waste, broadening the range of raw material selection for coal-water slurry gasification and reducing the cost of the coal-water slurry gasification process.

Description

Technical Field

[0001] This disclosure relates to the field of coal chemical technology, and in particular to a raw material pretreatment method and pretreatment system for a fluidized bed gasifier. Background Technology

[0002] Continuously promoting the efficient, clean, economical, and safe innovative development of coal gasification technology is key to achieving energy conservation and emission reduction in coal chemical projects. Coal-water slurry gasification technology, as an advanced and mature coal gasification technology, has advantages such as high gasification pressure, good matching with downstream purification and synthesis, safe and reliable coal slurry preparation, good transportation stability, and low equipment investment. It has been widely used in fields such as coal-to-methanol / olefins / ethylene glycol / synthetic ammonia / coal-to-hydrogen. However, the development of this technology also faces many limitations, including restricted coal selection, difficulty in coal slurry concentration, low energy efficiency, and high carbon emissions. In particular, the control of coal slurry concentration and the rheological properties of the coal-water slurry are closely related to the overall technical and economic indicators of the process.

[0003] Coal-water slurry gasification requires a gasifier. A gasifier can perform both coal-water slurry gasification and pulverized coal slurry gasification. Pulverized coal slurry is formed by mixing coal-water slurry and pulverized coal. During pulverized coal slurry gasification, the gasification effect of the components of the coal-water slurry in the pulverized coal slurry has a significant impact. Therefore, when using a gasifier, whether gasifying coal-water slurry or pulverized coal slurry, to ensure stable operation, it is necessary to use coal-water slurry with acceptable coal concentration and rheological properties. Raw material selection and control are key factors affecting the slurry-forming properties of coal-water slurry. Slurry made from high-rank coal can meet the standards, but high-rank coal is expensive. Low-quality coal, which is cheaper, has high moisture and ash content, resulting in poor slurry-forming properties and making it difficult to produce coal-water slurry that meets the gasifier's standards. This increases the implementation cost of coal-water slurry gasification, affecting its practical use and development. Summary of the Invention

[0004] In order to solve the above-mentioned technical problems, or at least partially solve the above-mentioned technical problems, this disclosure provides a raw material pretreatment method and pretreatment system for a fluidized bed gasifier.

[0005] This disclosure provides a method for pretreatment of raw materials for a fluidized bed gasifier, including the following steps:

[0006] S1: Pre-crush raw coal and / or solid waste to obtain crushed coal;

[0007] S2: The crushed coal is sent to the pre-treatment unit for crushing, dewatering, and reduction of oxygen-containing functional groups to obtain pulverized coal;

[0008] S3: The pulverized coal is sent to the washing unit for washing to remove water-soluble cations from the pulverized coal and obtain wet pulverized coal.

[0009] S4: Wet pulverized coal is fed into the pulping unit for pulping to obtain coal-water slurry.

[0010] Optionally, in step S1, the raw coal includes any one or more combinations of peat, lignite, and sub-bituminous coal, and the solid waste includes any one or more combinations of industrial waste, domestic waste, fly ash, and coke powder from the coal chemical industrial park.

[0011] Optionally, in step S1, the particle size of the obtained crushed coal is less than 10 mm.

[0012] Optionally, in step S2, the crushed coal is fed into a pretreatment unit for dehydration, reduction of oxygen-containing functional groups, and crushing treatment, specifically including:

[0013] S21, the crushed coal is fed into the coal mill for crushing, and at the same time, the steam-containing hot flue gas generated by the steam superheating mechanism is fed into the coal mill, so that the steam-containing hot flue gas comes into countercurrent contact with the crushed coal in the coal mill to perform hydrothermal modification on the crushed coal.

[0014] S22 separates the hydrothermally modified crushed coal through air classification. The crushed coal larger than the set particle size is returned to the coal mill for crushing. The crushed coal smaller than or equal to the set particle size enters the gas-solid separation mechanism under the drive of airflow for gas-solid separation to obtain pulverized coal and steam-containing hot gas.

[0015] Optionally, in step S21, the steam introduced into the steam superheating mechanism is water vapor from a public works system at a preset pressure. At the same time, purge gas and air with a set calorific value are introduced into the steam superheating mechanism to preheat the introduced water vapor through a combustion exothermic reaction, thereby obtaining steam-containing hot flue gas with a water vapor content of more than 40% at 250-400°C.

[0016] Optionally, in step S21, the pressure of the coal mill is 0.1-0.4 MPa, and the operating temperature of the coal mill is 130-180℃;

[0017] Optionally, step S22 further includes the following: after gas-solid separation by the gas-solid separation mechanism, part of the steam-containing hot gas is discharged into the air, and the other part is recycled into the steam superheating mechanism.

[0018] 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 proportion of pulverized coal particles with a particle size of less than 100 μm greater than 80%.

[0019] Optionally, step S3 further includes sending the water containing cations obtained after the water washing treatment into a biochemical treatment unit for wastewater treatment to recover salts.

[0020] Optionally, in step S4, the wet pulverized coal is fed into the pulping unit for pulping, specifically including:

[0021] Wet pulverized coal is fed into the slurry preparation unit, and water, additives, and high-rank coal for coal-water slurry are added to the slurry preparation unit. The mixture is then ground and slurried in the slurry preparation unit to obtain a coal-water slurry with a coal slurry concentration greater than 60%.

[0022] This disclosure also provides a raw material pretreatment system for a fluidized bed gasifier, comprising:

[0023] Raw material silos are used to store raw coal and / or solid waste.

[0024] A pre-crushing unit, connected to the raw material silo, is used to pre-crush the raw coal and / or solid waste to obtain crushed coal.

[0025] A pretreatment system, connected to the pre-crushing unit, is used to dehydrate, reduce oxygen-containing functional groups, and crush the pulverized coal to obtain pulverized coal.

[0026] A water washing unit, connected to the pretreatment unit, is used to wash the pulverized coal to remove water-soluble cations from the pulverized coal and obtain wet pulverized coal.

[0027] The pulping unit, connected to the washing unit, is used to pulp the wet pulverized coal to obtain coal-water slurry.

[0028] Optionally, the raw material warehouse includes a raw coal warehouse and a solid waste warehouse, wherein the raw coal warehouse is used to store low-rank coal and the solid waste warehouse is used to store solid waste from the coal chemical industrial park.

[0029] Optionally, the pretreatment unit includes a coal mill, a steam superheating mechanism, a blower, and a gas-solid separation mechanism. The coal mill has an internal working space for accommodating and crushing the pulverized coal. The coal mill has multiple connecting channels communicating with the working space. The steam superheating mechanism, the blower, and the gas-solid separation mechanism are respectively connected to the working space through the connecting channels. The blower is located at the bottom of the coal mill, and the gas-solid separation mechanism is located at the top of the coal mill. The coal mill is used to crush the fed pulverized coal. The steam superheating mechanism is used to introduce steam-containing hot flue gas into the coal mill to perform hydrothermal modification on the pulverized coal. The blower is used to blow air onto the hydrothermally modified pulverized coal to separate the pulverized coal according to its particle size. The gas-solid separation mechanism is used to perform gas-solid separation on pulverized coal smaller than a set particle size to obtain pulverized coal.

[0030] Optionally, the pulping unit includes a pulping device, a water tank, an additive tank, a coal-water slurry tank, and a high-rank coal bunker. The high-rank coal bunker is connected to the pulping device and is used to store and transport high-rank coal for coal-water slurry to the pulping device. The water tank, the additive tank, and the coal-water slurry tank are all connected to the pulping device. The water tank is used to supply water to the pulping device, the additive tank is used to supply additives to the pulping device, the pulping device is used to complete the mixing and pulping of wet pulverized coal with water, additives, and high-rank coal for coal-water slurry, and the coal-water slurry tank is used to store the coal-water slurry produced by the pulping device.

[0031] The technical solution provided in this disclosure has the following advantages compared with the prior art:

[0032] The raw material pretreatment method for a fluidized bed gasifier disclosed herein includes pre-crushing raw coal and / or solid waste to obtain pulverized coal, increasing the surface area of ​​the raw coal and solid waste to facilitate subsequent processing operations; feeding the pulverized coal into a pretreatment unit for crushing, dewatering, and reducing oxygen-containing functional groups to obtain pulverized coal. The pretreatment unit reduces the moisture content of the pulverized coal, lowers coal and oxygen consumption, and reduces oxygen-containing functional groups, thereby improving the hydrophobicity of the pulverized coal and giving the coal-water slurry good slurry-forming properties; and feeding the pulverized coal into a washing unit for washing to remove water-soluble cations from the pulverized coal, obtaining... Wet pulverized coal is obtained by reducing the content of water-soluble cations in the wet pulverized coal, thus avoiding the influence of water-soluble cations on the repulsive force between coal particles and reducing the fluidity of the coal-water slurry produced by pulverized coal. The wet pulverized coal is then fed into a slurry preparation unit to obtain coal-water slurry. Ultimately, after the low-quality coal with high moisture content and high ash content is treated by the raw material pretreatment method, a coal-water slurry raw material that meets the requirements of coal-water slurry gasification technology is obtained. This enables the produced coal-water slurry to meet the application standards of coal-water slurry gasification or pulverized slurry gasification, broadens the range of raw material selection for coal-water slurry gasification or pulverized slurry gasification processes, and reduces the cost of coal-water slurry gasification or pulverized slurry gasification processes. Attached Figure Description

[0033] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0034] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a flowchart illustrating the steps of the raw material pretreatment method for the fluidized bed gasifier described in the embodiments of this disclosure.

[0036] Figure 2 This is one of the schematic diagrams of the module structure of the raw material pretreatment system for the fluidized bed gasifier described in the embodiments of this disclosure.

[0037] Figure 3 This is the second schematic diagram of the raw material pretreatment system module for the fluidized bed gasifier described in this embodiment.

[0038] The components include: 1. Raw material silo; 11. Raw coal silo; 12. Solid waste silo; 2. Pre-crushing unit; 21. Crushed coal silo; 3. Pre-treatment unit; 31. Coal mill; 32. Fan; 33. Gas-solid separation mechanism; 34. Steam superheating mechanism; 4. Water washing unit; 5. Pulping unit; 51. Pulping device; 52. Water tank; 53. Additive tank; 54. High-rank coal silo; 55. Coal-water slurry tank. Detailed Implementation

[0039] To better understand the above-mentioned objectives, features, and advantages of this disclosure, the solutions disclosed herein will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0040] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some, and not all, of the embodiments of this disclosure.

[0041] Reference Figures 1 to 3 As shown in the figure, this disclosure provides a raw material pretreatment method for an entrained gasifier, including the following steps: S1: pre-crushing raw coal and / or solid waste to obtain crushed coal; S2: feeding the crushed coal into a pretreatment unit 3 for crushing, dewatering, and reducing oxygen-containing functional groups to obtain pulverized coal; S3: feeding the pulverized coal into a washing unit 4 for washing to remove water-soluble cations from the pulverized coal to obtain wet pulverized coal; S4: feeding the wet pulverized coal into a slurry preparation unit 5 for slurry preparation to obtain coal-water slurry.

[0042] Specifically, coal is usually classified using coal rank, a quantity used to describe the degree of coalification during coal formation. Both the physical and chemical properties of coal affect its rank. As the degree of coalification increases, coal evolves from its initial peat state, through lignite, sub-bituminous coal, bituminous coal, and anthracite. Low-rank lignite and sub-bituminous coal have high moisture content and low calorific value, resulting in low combustion efficiency as fuel. High-rank coal has low moisture content and high calorific value. In other words, as coal rank and maturity increase, the carbon content increases, while the hydrogen and oxygen content decrease. Furthermore, volatile matter decreases with increasing maturity. Generally, the lower the coal rank, the higher the internal water content, the higher the oxygen-to-carbon ratio, the more hydrophilic functional groups, and the greater the difficulty in pulping. Low-grade coal, also known as low-rank coal, has an increased number of carbonyl and aliphatic carbon groups, meaning it has more oxygen-containing hydrophilic functional groups and a higher oxygen-to-carbon ratio. As the number of hydrophilic functional groups increases, the hydrophilicity of the coal increases, and the free water decreases, which increases the viscosity of the coal-water slurry and consequently leads to poorer slurry-forming properties.

[0043] The raw coal can be selected as low-rank coal with a low degree of coal quality morphology. Low-rank coal has large reserves and low prices. Solid waste can be selected as combustible solid materials, such as solid waste from coal chemical industrial parks, including industrial waste, domestic waste, fly ash, and coke powder. The raw coal and solid waste can be put into a coal crusher with rotary blades, where the blades continuously impact the raw coal and solid waste for pre-crushing. Alternatively, a reciprocating vibrating structure in the coal crusher can be selected, where the raw coal and solid waste are subjected to vibration to crush them. The crushed coal obtained from the process is in the form of lumps or granules. The crushed coal can be obtained by pre-crushing raw coal, or by pre-crushing solid waste. It is not limited to obtaining crushed coal from a mixture of raw coal and solid waste. The crushed coal is not limited to being made solely from crushed coal lumps. After crushing, the solid waste also has combustible properties. Furthermore, the solid waste is waste from the coal industrial park and contains at least some coal components. Therefore, the crushed coal can be obtained by pre-crushing solid waste.

[0044] The aforementioned pretreatment unit 3 may include a coal crusher. The pulverized coal enters the crusher for further crushing into smaller coal lumps, thus reducing the particle size and facilitating water removal and reduction of oxygen-containing functional groups. Reducing the oxygen-containing functional groups of the pulverized coal can be achieved by introducing hot flue gas composed of purge gas and water vapor into the pulverized coal. Upon contact with the pulverized coal, the oxygen-containing functional groups on the coal surface react with water and decompose, while the microporous structure inside the coal shrinks and collapses, thereby irreversibly removing water from the coal. This reduction in oxygen-containing functional groups simultaneously lowers the particle size of the pulverized coal. Moisture content; the more oxygen-containing functional groups on the surface of coal, the stronger its hydrophilicity. When making coal-water slurry, a large number of water molecules will be adsorbed on the surface of the coal, increasing the internal moisture content of the coal. The internal moisture of the coal will form a solid hydration film on the surface of the coal particles, reducing the free flow of water and thus reducing the fluidity of the coal-water slurry. After the pretreatment unit 3, the particle size of the crushed coal is further reduced to form pulverized coal, which is easier to process into coal-water slurry. The reduced moisture content in the pulverized coal reduces the oxygen-containing functional groups, improves the hydrophobicity of the pulverized coal, and enhances its slurry-forming properties.

[0045] The aforementioned washing unit 4 can be selected as a washing tank for placing pulverized coal. The pulverized coal is placed in the washing tank and washed with water, thereby dissolving the water-soluble cations in the pulverized coal into the water, thus reducing the content of water-soluble cations in the pulverized coal. After washing, the pulverized coal carries some water and forms wet pulverized coal. The cations on the coal surface will reduce the anionic potential on the surface of the coal particles, reduce the repulsive force between solid particles, and cause the viscosity of the prepared coal-water slurry to increase, affecting the fluidity of the coal-water slurry.

[0046] The aforementioned pulping unit 5 can be selected as a container for holding wet pulverized coal with a mixer. The wet pulverized coal is placed in the container, and water and additives are added to the container. Under the action of the mixer, the wet pulverized coal, additives and water are mixed evenly to form a coal-water slurry.

[0047] The raw material pretreatment method for a fluidized bed gasifier provided in this embodiment includes a warehouse for storing raw coal and solid waste. The raw coal and solid waste in the warehouse are transferred to a coal crusher via a conveyor belt or transfer vehicle to pre-crush the raw coal and solid waste to obtain crushed coal. The crushed coal is then subjected to dehydration, reduction of oxygen-containing functional groups, and crushing treatment in a pretreatment unit 3 to obtain pulverized coal. After being treated in a water washing unit 4, water-soluble cations in the pulverized coal are removed to obtain wet pulverized coal. The wet pulverized coal is then sent to a slurry preparation unit 5 to produce coal-water slurry.

[0048] A typical Xinjiang coal type was selected as the raw material for the pretreatment method of the fluidized bed gasifier. The coal quality analysis is as follows:

[0049]

[0050] The coal slurry concentration and fluidity parameters obtained before processing this type of coal using the pretreatment method for fluidized bed gasification furnace are as follows:

[0051]

[0052] After being processed by the raw material pretreatment method in the fluidized bed gasifier, the coal slurry concentration and fluidity indicators are as follows:

[0053]

[0054] The oxygen-to-carbon ratio can be obtained using the elemental analysis method for coal as specified in GB47691. The apparent viscosity can be obtained using GBT 18856.4-2008 Test Methods for Coal-Water Slurry, Part 4: Determination of Apparent Viscosity. The 24-hour water separation rate can be determined by sealing the coal-water slurry and allowing it to stand for 24 hours, then measuring the weight of the water separated from the slurry. The weight of the water separated from the slurry is the proportion of the total weight of the coal-water slurry after standing. The fluidity can be determined by using a 16mm funnel, pouring the coal-water slurry into the funnel, and observing the flow state of the slurry through the funnel. The stability can be determined by sealing the coal-water slurry and allowing it to stand for 24 hours, then observing the sediment that forms after standing and determining the hardness of the sediment.

[0055] Water-coal slurries prepared from the same coal type before and after raw material pretreatment were used for gasification. During the gasification process, the operating pressure of the fluidized bed gasifier was controlled at 4 MPa and the temperature at 1350℃. The specific indicators obtained and the comparison of indicators before and after the raw material pretreatment method for the fluidized bed gasifier are as follows:

[0056]

[0057]

[0058] After the coal is pretreated by the fluidized bed gasifier, the resulting coal-water slurry has improved slurry concentration and flow characteristics, increased effective gas production, and reduced coal and oxygen consumption. Under the same coal input, the increase in effective gas and the reduction in coal and oxygen consumption improve energy conversion efficiency and reduce the implementation cost of the coal-water slurry gasification process, thereby improving technical and economic indicators.

[0059] The pretreatment method for raw materials in a fluidized bed gasifier includes pre-crushing the raw coal and / or solid waste to obtain pulverized coal, increasing the surface area of ​​the raw coal and solid waste for easier subsequent processing. The pulverized coal is then fed into a pretreatment unit 3 for crushing, dewatering, and reduction of oxygen-containing functional groups to obtain pulverized coal. Pretreatment unit 3 reduces the moisture content of the pulverized coal, lowers coal and oxygen consumption, and reduces oxygen-containing functional groups, thereby improving the hydrophobicity of the pulverized coal and giving the coal-water slurry good slurry-forming properties. Finally, the pulverized coal is fed into a washing unit 4 for washing to remove water-soluble cations, obtaining wet pulverized coal. The content of water-soluble cations is reduced to avoid the water-soluble cations affecting the repulsive force between coal particles and reducing the fluidity of the coal-water slurry made from pulverized coal. Wet pulverized coal is sent to the slurry preparation unit 5 for slurry preparation to obtain coal-water slurry. Finally, the low-rank coal with high moisture content and high ash content is processed by the raw material pretreatment method to obtain coal-water slurry raw material that meets the requirements of coal-water slurry gasification technology. The obtained coal-water slurry meets the application standards of coal-water slurry gasification or pulverized slurry gasification, which broadens the range of raw material selection for coal-water slurry gasification or pulverized slurry gasification processes and reduces the cost of coal-water slurry gasification or pulverized slurry gasification processes.

[0060] Reference Figures 1 to 3 As shown, in some embodiments, in step S1, the raw coal includes any one or more combinations of peat, lignite, and sub-bituminous coal, and the solid waste includes any one or more combinations of industrial waste, domestic waste, fly ash, and coke powder from the coal chemical industrial park.

[0061] Specifically, the raw coal can be peat, lignite, or even sub-bituminous coal, as long as it is a low-priced, low-quality or low-rank coal. Industrial waste, domestic waste, fly ash, and coke powder in the coal chemical industrial park are all combustible solid waste and can be used as fuel. Mixing them with low-rank coal can further reduce the raw material cost for subsequent coal-water slurry production. Alternatively, the solid waste can be pre-crushed to form lumps of combustible solids for use as pulverized coal. The raw coal and solid waste can be mixed and pre-crushed together, or only the raw coal or only the solid waste can be pre-crushed, depending on the actual situation in industrial production.

[0062] By setting the raw coal to include any one or more combinations of peat, lignite, and sub-bituminous coal, and the solid waste to include any one or more combinations of industrial waste, domestic waste, fly ash, and coke powder from coal chemical industrial parks, the raw coal is made into a mixture of low-priced low-rank coal and solid waste, thereby reducing the raw material cost of preparing coal-water slurry. Mixing solid waste with raw coal further reduces the raw material cost of preparing coal-water slurry while utilizing waste.

[0063] Reference Figures 1 to 3 As shown, in some embodiments, in step S1, the particle size of the pulverized coal obtained is less than 10 mm.

[0064] Specifically, raw coal and solid waste can be pre-crushed together, or only raw coal can be pre-crushed. The maximum particle size of the resulting particles is less than 10 mm, which increases the contact area of ​​the raw coal and makes it easier to process the raw coal into pulverized coal after crushing.

[0065] By setting the particle size of the crushed coal obtained in step S1 to be less than 10mm, the original large-volume raw coal is broken into granules, which increases the surface area of ​​the raw coal and improves the efficiency of subsequent dewatering and reduction of oxygen-containing functional groups. Furthermore, pre-crushing into particles of less than 10mm can reduce the crushing time in step S2, allowing the crushed coal to be processed into pulverized coal more quickly.

[0066] Reference Figures 1 to 3 As shown, in some embodiments, in step S2, the pulverized coal is fed into the pretreatment unit 3 for dehydration, reduction of oxygen-containing functional groups, and crushing treatment. Specifically, this includes: S21, feeding the pulverized coal into the coal mill 31 for crushing, and simultaneously feeding the steam-containing hot flue gas generated by the steam superheating mechanism 34 into the coal mill 31, so that the steam-containing hot flue gas comes into countercurrent contact with the pulverized coal in the coal mill 31 to perform hydrothermal modification on the pulverized coal; S22, separating the hydrothermally modified pulverized coal by air classification, pulverized coal larger than the set particle size is returned to the coal mill 31 for crushing treatment, and pulverized coal smaller than or equal to the set particle size enters the gas-solid separation mechanism 33 under the drive of airflow for gas-solid separation to obtain pulverized coal and steam-containing hot gas.

[0067] Specifically, the coal mill 31 can be a mill with a grinding disc structure, where the pulverized coal changes from lumpy particles to powder under the action of the grinding disc; the steam superheating mechanism 34 can be selected to include a gas mixing section and a heating section, where purge gas, water vapor, and air are introduced into the gas mixing section, and the heating section is used to heat the gas in the gas mixing section to obtain steam-containing hot flue gas. The water vapor content in the steam-containing hot flue gas can be selected to be above 40%, and the temperature of the steam-containing hot flue gas can be between 250°C and 400°C. The pulverized coal moves in one direction in the coal mill 31, and the steam-containing hot flue gas is introduced into the coal mill 31, with the direction of movement of the steam-containing hot flue gas in the coal mill 31 opposite to the direction of movement of the pulverized coal, so as to achieve countercurrent contact between the steam-containing hot flue gas and the pulverized coal in the coal mill 31, so that the steam-containing hot flue gas and the pulverized coal can fully contact each other, and so that the steam-containing hot flue gas and the pulverized coal can fully carry out the hydrothermal modification reaction.

[0068] The aforementioned hydrothermal modification reaction involves the reaction of high-temperature steam with oxygen-containing functional groups on the surface of pulverized coal, reducing the number of oxygen-containing functional groups in the pulverized coal. Furthermore, the high-temperature hot flue gas causes the microporous structure inside the pulverized coal to shrink and collapse, reducing the water content within the pulverized coal. The crushing process further reduces the particle size of the pulverized coal. The further crushing of the pulverized coal increases its contact area with the steam-containing hot flue gas, accelerating the reaction efficiency of hydrothermal modification. Moreover, the pulverized coal formed by crushing facilitates the subsequent preparation of coal-water slurry. The high-temperature steam-containing hot flue gas can also dry the coal particles in the coal mill.

[0069] The aforementioned air separation involves the pulverized coal in the coal mill 31 undergoing hydrothermal modification for a set time. Then, a blower 32 blows coal particles smaller than or equal to a set particle size into the gas-solid separation mechanism 33. The direction of the airflow created by the blower 32 can be upward, or it can be tilted upward with the blower 32 pointing towards the gas-solid separation mechanism 33. As the pulverized coal passes through the airflow, particles with a diameter smaller than or equal to the set particle size are lighter and can be carried into the gas-solid separation mechanism 33. Particles larger than the set particle size are heavier and cannot be blown away by the airflow, falling back into the coal mill 31 for further pulverization. The set time can be 30 minutes, 1 hour, or other durations, determined based on the type of coal and the specific process.

[0070] The gas-solid separation mechanism 33 mentioned above can be a filter bag with pores. The diameter of the pores is smaller than the set particle size. The crushed coal and steam-containing hot flue gas enter the filter bag, and the steam-containing hot flue gas passes through the pores and exits the filter bag, leaving the crushed coal in the filter bag to form pulverized coal.

[0071] In step S2, the pulverized coal is fed into the pretreatment unit 3 for dehydration, reduction of oxygen-containing functional groups, and crushing. Specifically, this includes: S21, feeding the pulverized coal into the coal mill 31 for crushing, while simultaneously feeding the steam-containing hot flue gas generated by the steam superheating mechanism 34 into the coal mill 31, causing the steam-containing hot flue gas to come into countercurrent contact with the pulverized coal in the coal mill 31, thus performing hydrothermal modification on the pulverized coal; S22, separating the hydrothermally modified pulverized coal through air classification, returning pulverized coal larger than the set particle size to the coal mill 31 for further crushing, and smaller pulverized coal... The crushed coal of a set particle size is driven by airflow into the gas-solid separation mechanism 33 for gas-solid separation, resulting in pulverized coal and steam-containing hot gas. Finally, the steam-containing hot flue gas comes into countercurrent contact with the crushed coal, allowing for full contact and hydrothermal reaction. The crushed coal is further crushed in the coal mill 31, increasing its contact area with the steam-containing hot flue gas and improving the efficiency of the hydrothermal reaction. Air classification can conveniently send crushed coal that meets the particle size requirements into the gas-solid separation mechanism 33, improving the efficiency of the crushed coal in the pretreatment unit 3.

[0072] Reference Figures 1 to 3 As shown, in some embodiments, in step S21, the steam introduced into the steam superheating mechanism 34 is water vapor from a public works system at a preset pressure. At the same time, purge gas and air with a set calorific value are introduced into the steam superheating mechanism 34. The introduced water vapor is preheated by the combustion exothermic reaction to obtain steam-containing hot flue gas with a water vapor content of more than 40% at 250-400°C.

[0073] Specifically, one can choose the steam pipeline provided by the public works system for the project or industrial park. Purge gas is a material name used in chemical production. In many chemical production processes, to maintain chemical reaction balance, efficiency, normal and stable operation, gases generated by side reactions or remaining components from mixed gas feedstocks, as well as all or part of low-grade gas components that can no longer be used in the chemical process, are continuously or periodically discharged from the production unit. This portion of gas is called purge gas. The set calorific value of purge gas is determined based on its composition.

[0074] The preset pressure can be selected as 0.5MPa or 0.2MPa. The utility system usually only provides steam at a stable pressure value according to the design. This pressure value is the preset pressure. The preset pressure can be selected as 0.2MPa, 0.5MPa or 1.2MPa. Of course, depending on the actual situation of the utility system, other pressure values ​​of steam may be provided. As long as the steam superheating mechanism is directly connected to the steam with the preset pressure provided by the utility system, the existing factory steam settings can be used, and there is no need to set up a separate boiler to provide steam.

[0075] In step S21, the steam introduced into the steam superheating mechanism 34 is water vapor from a pre-set pressure in the utility system. At the same time, purge gas and air with a set calorific value are introduced into the steam superheating mechanism 34. The introduced water vapor is preheated through the combustion exothermic reaction, resulting in steam-containing hot flue gas at 250-400℃ with a water vapor content of more than 40%. The mixing of purge gas and water vapor reduces the cost of producing hot flue gas. The steam-containing hot flue gas is between 250℃ and 400℃. Within this temperature range, the water vapor in the hot flue gas can react with the oxygen-containing functional groups in the coal, causing the oxygen-containing functional groups to decompose. The water vapor content of more than 40% ensures that the hot flue gas can fully react with the oxygen-containing functional groups in the pulverized coal, guaranteeing the effect of the hot flue gas in removing oxygen-containing functional groups from the pulverized coal.

[0076] Reference Figures 1 to 3 As shown, in some embodiments, in step S21, the pressure of the coal mill 31 is 0.1-0.4 MPa, specifically 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, etc., and the operating temperature of the coal mill 31 is 130-180℃, specifically 130℃, 150℃, 180℃, etc.

[0077] Specifically, the pressure of the coal mill 31 is the pressure applied to the crushed coal blocks inside the coal mill 31 during operation. The pressure can be set to 0.2 MPa or 0.4 MPa. The pressure of the coal mill 31 is related to the model and power of the coal mill 31. Different models and power of the selected coal mill 31 will have different set pressure values. The operating temperature of the coal mill 31 is the overall temperature of the coal mill 31 during operation. The operating temperature of the coal mill 31 is 130℃ to 180℃.

[0078] By setting the pressure of the coal mill 31 to 0.1-0.4 MPa and the operating temperature of the coal mill 31 to 130-180℃ in step S21, it is ensured that the coal mill 31 can further crush the coal and reduce the rate of heat loss during the reaction of steam-containing hot flue gas in the coal mill 31, thus ensuring the smooth progress of the hydrothermal modification reaction.

[0079] Reference Figures 1 to 3 As shown, in some embodiments, step S22 further includes the following: the steam-containing hot gas obtained after gas-solid separation by the gas-solid separation mechanism 33 is partially discharged into the air and the other part enters the steam superheating mechanism 34 for recycling.

[0080] Specifically, the steam-containing hot flue gas undergoes a hydrothermal modification reaction with the crushed coal in the coal mill 31, causing some of the released gas in the steam-containing hot flue gas to react with and be consumed by the crushed coal, thereby turning the steam-containing hot flue gas into steam-containing hot gas. The crushed coal that has undergone hydrothermal modification after crushing is blown into the gas-solid separation mechanism 33 along with the steam-containing hot gas during the air classification process. The gas-solid separation mechanism 33 is connected to the steam superheating mechanism 34 through a gas guide pipe. After separation by the gas-solid separation mechanism 33, the crushed coal that has undergone air classification remains in the gas-solid separation mechanism 33, while the steam-containing hot gas is discharged into the steam superheating mechanism 34 for recycling. Some of the steam-containing hot gas will escape into the air.

[0081] The step S22 also includes the following: after gas-solid separation by the gas-solid separation mechanism 33, part of the steam-containing hot flue gas is discharged into the air, and the other part enters the steam superheating mechanism 34 for recycling. This allows the steam-containing hot flue gas, which maintains a certain temperature, to return to the steam superheating mechanism 34 for recycling after separation from the crushed coal that has undergone air separation by the gas-solid separation mechanism 33. This reduces the energy required to maintain the temperature of the steam-containing hot flue gas.

[0082] Reference Figures 1 to 3 As shown, 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 a proportion of pulverized coal particles with a particle size of less than 100 μm greater than 80%.

[0083] Specifically, it can be selected that, during the air classification of crushed coal into powder, due to the continuous movement of the crushed coal driven by the mill, some crushed coal particles with a particle size larger than the set particle size may enter the gas-solid separation mechanism 33 under the action of kinetic energy. Therefore, it is only necessary for the proportion of pulverized coal particles with a particle size of less than 100μm to be greater than 80% to meet the requirements of pulverized coal. The particle size of pulverized coal is less than 100μm, which facilitates its subsequent mixing with water to prepare coal-water slurry. The internal water content of pulverized coal is less than 5%, which ensures the fluidity of the coal-water slurry prepared by pulverized coal. The O / C mass ratio is less than 0.2, which indicates that there are fewer oxygen-containing functional groups in pulverized coal, so that the coal-water slurry prepared by pulverized coal has good slurry-forming properties.

[0084] By setting the pulverized coal in step S2 to have an internal water content of less than 5%, an O / C mass ratio of less than 0.2, and a proportion of pulverized coal particles with a particle size of less than 100 μm greater than 80%, the physical properties of the pulverized coal after treatment are suitable for preparing a coal-water slurry with good slurry properties.

[0085] Reference Figures 1 to 3 As shown, in some embodiments, step S3 further includes sending the water containing cations obtained after water washing into a biochemical treatment unit for wastewater treatment to recover salts.

[0086] Specifically, water containing cations usually contains metal cations of high-value metals, and the biochemical treatment unit can prepare salt compounds from the cations dissolved in the water after washing treatment.

[0087] Step S3 also includes sending the water containing cations obtained after water washing to a biochemical treatment unit for wastewater treatment to recover salts, improve the utilization rate of raw materials, increase the variety of economically valuable products produced by the raw material pretreatment system for the fluidized bed gasifier, and improve economic benefits.

[0088] Reference Figures 1 to 3 As shown, in some embodiments, in step S4, wet pulverized coal is fed into the slurry preparation unit 5 for slurry preparation. Specifically, this includes: feeding wet pulverized coal into the slurry preparation unit 5, adding water, additives, and high-rank coal for coal-water slurry to the slurry preparation unit 5, and mixing and grinding the slurry in the slurry preparation unit 5 to obtain a coal-water slurry with a coal slurry concentration greater than 60%.

[0089] Specifically, the pulping unit 5 includes at least a pulping tank for stirring and mixing. Wet pulverized coal, water, additives and a portion of coal-water slurry are mixed in the pulping tank to obtain coal-water slurry. The high-rank coal used in the coal-water slurry is pulverized coal with low oxygen content and low internal water content.

[0090] In step S4, wet pulverized coal is fed into the slurry preparation unit 5 for slurry preparation. Specifically, this includes feeding wet pulverized coal into the slurry preparation unit 5, adding water, additives, and high-rank coal for coal-water slurry to the slurry preparation unit 5, mixing and grinding the pulverized coal in the slurry preparation unit 5 to obtain a coal-water slurry with a coal slurry concentration greater than 60%, and finally making the wet pulverized coal fully mixed with water, additives, and high-rank coal for coal-water slurry in the slurry preparation unit 5 to obtain a coal-water slurry.

[0091] Reference Figures 1 to 3 As shown, this disclosure also provides a raw material pretreatment system for a fluidized bed gasifier, including a raw material silo 1 for storing raw coal and / or solid waste;

[0092] The pre-crushing unit 2 is connected to the raw material silo 1 and is used to pre-crush raw coal and / or solid waste to obtain crushed coal.

[0093] Pre-treatment unit 3, connected to pre-crushing unit 2, is used to dehydrate, reduce oxygen-containing functional groups, and crush coal to obtain pulverized coal.

[0094] The water washing unit 4 is connected to the pretreatment unit 3 and is used to wash the pulverized coal to remove water-soluble cations from the pulverized coal to obtain wet pulverized coal.

[0095] The pulping unit 5 is connected to the washing unit 4 and is used to pulp wet pulverized coal to obtain coal-water slurry.

[0096] Specifically, the pre-crushing unit 2 can include a coal crusher, which can be equipped with blades that collide with the raw coal to crush it. Alternatively, the coal crusher can be equipped with a vibration device, which vibrates the raw coal to crush it and complete the pre-crushing process. The pre-crushing unit 2 can also include a crushing bin 21, in which the crushed coal is stored. The crushing bin 21 is connected to the subsequent pre-processing unit 3 via a conveyor belt. The raw material bin 1 can be connected to the pre-crushing unit 2 via a conveyor belt or a conveying pipe.

[0097] The aforementioned pretreatment unit 3 includes a coal mill 31 and an aeration device. The coal mill 31 has a grinding disc or grinding roller to crush the coal. The aeration device is used to introduce gas for hydrothermal modification into the mill. The washing unit 4 is connected to the pretreatment unit 3 via a conveyor belt or conveying pipe. A slurry preparation unit 5 is set downstream of the washing unit 4. The slurry preparation unit 5 can be equipped with a tank for holding wet pulverized coal. The tank can be set downstream of the washing unit 4 so that the wet pulverized coal can enter the slurry preparation unit 5 after leaving the washing unit 4.

[0098] The system includes a raw material silo 1 for storing raw coal and / or solid waste to prevent contamination by foreign matter; a pre-crushing unit 2 connected to the raw material silo 1 for pre-crushing the raw coal and / or solid waste to obtain pulverized coal, reducing the particle size of larger raw materials and facilitating the subsequent production of pulverized coal suitable for coal-water slurry; a pre-treatment unit 3 connected to the pre-crushing unit 2 for dehydrating, reducing oxygen-containing functional groups, and crushing the pulverized coal to obtain pulverized coal, reducing the oxygen-containing functional groups and improving the hydrophobicity of the pulverized coal, thus giving it good slurry-forming properties; a washing unit 4 connected to the pre-treatment unit 3 for washing the pulverized coal to remove water-soluble cations and obtain wet pulverized coal; and a slurry preparation unit 5 connected to the washing unit 4 for slurry preparation of the wet pulverized coal to obtain coal-water slurry. Ultimately, the raw material silo 1, pre-crushing unit 2, pre-treatment unit 3, washing unit 4, and slurry preparation unit 5 are interconnected to form a complete system, working together to efficiently complete the pre-treatment of raw materials for the fluidized bed gasifier.

[0099] Reference Figures 1 to 3 As shown, in some embodiments, the raw material warehouse 1 includes a raw coal warehouse 11 and a solid waste warehouse 12. The raw coal warehouse 11 is used to store low-rank coal, and the solid waste warehouse 12 is used to store solid waste from the coal chemical industrial park.

[0100] Specifically, the raw coal bunker 11 and the solid waste bunker 12 can be connected to the pre-crushing unit 2 via conveyor belts, or the raw coal bunker 11 and the solid waste bunker 12 can be connected to the pre-crushing unit 2 via conveyor pipes.

[0101] By setting up a raw material warehouse 1, which includes a raw coal warehouse 11 and a solid waste warehouse 12, the raw coal warehouse 11 is used to store low-rank coal, and the solid waste warehouse 12 is used to store solid waste from the coal chemical industrial park, so that low-rank coal and solid waste warehouse 12 are stored separately, which facilitates management.

[0102] Reference Figures 1 to 3 As shown, in some embodiments, the pre-processing unit 3 includes a coal mill 31, a steam superheating mechanism 34, a blower 32, and a gas-solid separation mechanism 33. The coal mill 31 has a working space inside for accommodating and crushing coal. The coal mill 31 has multiple connecting channels communicating with the working space. The steam superheating mechanism 34, the blower 32, and the gas-solid separation mechanism 33 are respectively connected to the working space through the connecting channels. The blower is located at the bottom of the coal mill 31, and the gas-solid separation mechanism 33 is located at the top of the coal mill 31. The coal mill 31 is used to crush the fed coal. The steam superheating mechanism 34 is used to introduce steam-containing hot flue gas into the coal mill 31 to perform hydrothermal modification on the coal. The blower 32 is used to blow air onto the hydrothermally modified coal so that the coal is separated according to its particle size. The gas-solid separation mechanism 33 is used to perform gas-solid separation on the coal smaller than the set particle size to obtain pulverized coal.

[0103] Specifically, the coal mill 31 can include a coal grinding disc and a coal grinding roller. The coal mill 31 has a cavity as a working space, and the coal grinding disc and the coal grinding roller are set in the cavity. The surface of the coal mill 31 is provided with three through holes as connection channels. The steam superheating mechanism 34, the blower 32, and the gas-solid separation mechanism 33 are connected to the three through holes one by one, thereby communicating with the cavity. The gas-solid separation mechanism 33 is connected to the cavity and the steam superheating mechanism 34. The steam superheating mechanism 34 includes a mixing chamber for mixing gas and a heating section, and the heating section is used to heat the mixing chamber. The blower 32 is set below the gas-solid separation mechanism 33 and blows air towards the communication port between the gas-solid separation mechanism 33 and the cavity, thereby using the air field generated by the blower 32 to perform air separation of coal particles of different sizes. The gas-solid separation mechanism 33 includes at least a filtration mechanism, which only allows gas to pass through, thereby allowing the gas-solid separation mechanism 33 to separate the coal and the steam-containing hot flue gas.

[0104] The pre-processing unit 3 includes a coal mill 31, a steam superheating mechanism 34, a blower 32, and a gas-solid separation mechanism 33. The steam superheating mechanism 34, the blower 32, and the gas-solid separation mechanism 33 are all connected to the interior of the coal mill 31 to further crush the coal inside the mill. The steam superheating mechanism 34 performs hydrothermal modification, and the blower 32 performs air separation. The coal mill 31 is used to crush the fed coal. The steam superheating mechanism 34 is used to introduce steam-containing hot flue gas into the coal mill 31 to perform hydrothermal modification on the coal. The blower 32 is used to blow air onto the hydrothermally modified coal so that the coal is separated according to its particle size. The gas-solid separation mechanism 33 is used to perform gas-solid separation on the coal smaller than the set particle size to obtain pulverized coal. Finally, the coal mill 31, the steam superheating mechanism 34, the blower 32, and the gas-solid separation mechanism 33 cooperate with each other to complete the further crushing, hydrothermal modification, and air separation operations of the coal.

[0105] Reference Figure 2 and Figure 3 As shown, in some embodiments, the pulping unit 5 includes a pulping device 51, a water tank 52, an additive tank 53, a coal-water slurry tank 55, and a high-rank coal bunker 54. The high-rank coal bunker 54 is connected to the pulping device 51 and is used to store high-rank coal for coal-water slurry and to transport the high-rank coal for coal-water slurry into the pulping device 51. The water tank 52, the additive tank 53, and the coal-water slurry tank 55 are all connected to the pulping device 51. The water tank 52 is used to transport water to the pulping device 51, the additive tank 53 is used to transport additives to the pulping device 51, the pulping device 51 is used to complete the mixing and pulping of wet pulverized coal with water, additives, and high-rank coal for coal-water slurry, and the coal-water slurry tank 55 is used to store the coal-water slurry produced by the pulping device 51.

[0106] Specifically, the pulping device 51 can be a tank with an agitator. The water tank 52 and the additive tank are connected to the tank. The high-rank coal bunker 54 is connected to the pulping device 51 via a conveyor belt. The washing unit 4 is connected to the pulping device 51. After the wet pulverized coal is put into the tank of the pulping device 51, the water tank 52 adds water to the tank, the additive tank 53 adds additives to the tank, and the high-rank coal bunker 54 adds high-rank coal to the tank. The agitator in the tank mixes the wet pulverized coal, water, additives, and high-rank coal to produce coal-water slurry. A coal-water slurry tank 55 is set downstream of the pulping device 51 and is connected to the pulping device 51 so that the coal-water slurry in the pulping device 51 can flow into the coal-water slurry tank 55 for storage.

[0107] The raw material pretreatment method and system for a fluidized bed gasifier provided in this embodiment are implemented as follows: Raw coal and solid waste are transferred from the raw coal silo 11 and solid waste silo 12, respectively, to the pre-crushing unit 2 for pre-crushing to obtain crushed coal. The crushed coal is stored in the crushed coal silo 21, and then transferred to the crushing mill 31 in the pretreatment unit 3 for further crushing. A steam superheating mechanism 34 supplies steam-containing hot flue gas to the crushing mill 31. The steam-containing hot flue gas reacts with the crushed coal in the crushing mill 31 in a hydrothermal modification reaction. After a set time for the hydrothermal modification reaction, a blower 32 performs air separation on the crushed coal in the crushing mill 31, blowing coal particles with a particle size less than or equal to a set particle size to the gas-solid separation mechanism 33 for gas-solid separation. Unit 33 separates steam-containing hot flue gas and air-classified crushed coal particles to obtain pulverized coal. Part of the steam-containing flue gas separated by the gas-solid separation unit 33 is returned to the steam superheating unit 34 for recycling. The pulverized coal is transported to the water washing unit 4 for water washing treatment to remove water-soluble cations in the pulverized coal and obtain wet pulverized coal. The water containing cations obtained after 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, and water, additives and high-rank coal are added to the pulping device 51 through the water tank 52, the additive tank 53 and the high-rank coal bunker 54. The pulping device 51 mixes the wet pulverized coal, water, additives and high-rank coal to produce water-coal slurry. The water-coal slurry produced by the pulping device 51 is transported to the water-coal slurry tank 55 for storage.

[0108] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0109] The above description is merely a specific embodiment of this disclosure, enabling those skilled in the art to understand or implement it. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for pre-treating feedstock for use in an entrained flow gasifier, characterized by, The method comprises the following steps: S1: raw coal and / or solid waste are pre-crushed to obtain crushed coal; S2: the crushed coal is sent to a pre-treatment unit for crushing, water removal, and oxygen functional group reduction to obtain pulverized coal; S3: the pulverized coal is sent to a water washing unit for water washing to remove water-soluble cations in the pulverized coal, and wet pulverized coal is obtained; S4: the wet pulverized coal is sent to a slurry preparation unit for slurry preparation to obtain coal water slurry; In step S2, the crushed coal is sent to a pre-treatment unit for water removal, oxygen functional group reduction, and crushing. Specifically, the step comprises: S21: the crushed coal is sent to a crushed coal mill for pulverization, and steam-containing hot flue gas generated by a steam superheating mechanism is sent to the crushed coal mill, so that the steam-containing hot flue gas and the crushed coal are countercurrently contacted in the crushed coal mill to perform hydrothermal modification on the crushed coal; S22: the crushed coal after hydrothermal modification is separated by air separation. The crushed coal larger than a set particle size is returned to the crushed coal mill for crushing, and the crushed coal smaller than or equal to the set particle size is separated by gas-solid separation after being carried by air to obtain pulverized coal and steam-containing hot gas.

2. The feedstock pretreatment method for an entrained-flow gasifier according to claim 1, characterized by, In step S1, the raw coal comprises any one or a combination of peat, lignite, and sub-bituminous coal, and the solid waste comprises any one or a combination of industrial waste, household waste, fly ash, and coke powder in a coal chemical park.

3. The feedstock pretreatment method for an entrained-flow gasifier according to claim 1, characterized by, In step S1, the particle size of the crushed coal is less than 10 mm.

4. The feedstock pretreatment method for an entrained-flow gasifier according to claim 1, characterized by, In step S21, the steam from a utility system is introduced into the steam superheating mechanism at a preset pressure. At the same time, air and flue gas at a set calorific value are introduced into the steam superheating mechanism to preheat the introduced steam through a combustion heat release reaction, and 250-400℃ steam-containing hot flue gas with a steam content of more than 40% is obtained; And / or, in step S21, the pressure of the crushed coal mill is 0.1-0.4 MPa, and the working temperature of the crushed coal mill is 130-180℃; And / or, in step S22, the steam-containing hot gas obtained after gas-solid separation is partially discharged into air, and the other part is introduced into the steam superheating mechanism for recycling.

5. The feedstock pretreatment method for an entrained-flow gasifier according to claim 1, characterized by, In step S2, 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 proportion of pulverized coal particles with a particle size of less than 100 μm is greater than 80%.

6. The feedstock pretreatment method for an entrained-flow gasifier according to claim 1, characterized by, In step S3, the water containing cations obtained after water washing is sent to a biochemical treatment unit for wastewater treatment to recover salts.

7. The feedstock pretreatment method for an entrained-flow gasifier according to claim 1, characterized by, In step S4, the wet pulverized coal is sent to a slurry preparation unit for slurry preparation. Specifically, the step comprises: The wet pulverized coal is sent to a slurry preparation unit, and water, additives, and high-rank coal for coal water slurry are added to the slurry preparation unit. The wet pulverized coal, water, additives, and high-rank coal for coal water slurry are mixed and ground in the slurry preparation unit to obtain coal water slurry with a concentration of greater than 60%.

8. A feedstock pretreatment system for an entrained flow gasifier, characterized by, The method comprises the following steps: A raw material bin for storing raw coal and / or solid waste; A pre-crushing unit connected to the raw material bin for pre-crushing the raw coal and / or solid waste to obtain crushed coal; A pre-treatment unit connected to the pre-crushing unit for water removal, oxygen functional group reduction, and crushing of the crushed coal to obtain pulverized coal; a water washing unit, connected with the pre-treatment unit, for water washing the pulverized coal to remove water-soluble cations in the pulverized coal to obtain wet pulverized coal; a slurry preparation unit, connected with the water washing unit, for slurry preparation of the wet pulverized coal to obtain coal water slurry; the pre-treatment unit comprises a coal crushing mill, a steam superheating mechanism, a fan and a gas-solid separation mechanism, the coal crushing mill is internally provided with a working space for accommodating and crushing the crushed coal, the coal crushing mill is provided with a plurality of connecting channels in communication with the working space, the steam superheating mechanism, the fan and the gas-solid separation mechanism are respectively in communication with the working space through the connecting channels, the fan is located at the bottom of the coal crushing mill, and the gas-solid separation mechanism is located at the top of the coal crushing mill, the coal crushing mill is used for crushing the crushed coal sent in, the steam superheating mechanism is used for introducing steam-containing hot flue gas into the coal crushing mill to hydrothermally modify the crushed coal, the fan is used for blowing the hydrothermally modified crushed coal to separate the crushed coal according to particle size, and the gas-solid separation mechanism is used for gas-solid separation of the crushed coal with a particle size less than a set particle size to obtain pulverized coal.

9. The feedstock pretreatment system for an entrained flow gasifier as recited in claim 8, wherein, the raw material bin comprises a raw coal bin and a solid waste bin, 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; and / or, the slurry preparation unit comprises a slurry preparation device, a water tank, an additive tank, a coal water slurry tank and a high-rank coal bin, the high-rank coal bin is connected with the slurry preparation device and is used for storing high-rank coal for coal water slurry and conveying the high-rank coal for coal water slurry to the slurry preparation device, the water tank, the additive tank and the coal water slurry tank are all connected with the slurry preparation device, the water tank is used for conveying water to the slurry preparation device, the additive tank is used for conveying additives to the slurry preparation device, the slurry preparation device is used for completing mixing and slurry preparation of the wet pulverized coal, water and additives and high-rank coal for coal water slurry, and the coal water slurry tank is used for storing the coal water slurry prepared by the slurry preparation device.

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