Gasification fine slag deep dewatering system and method based on microwave vacuum synergistic drying

Abstract

The application discloses a gasification fine slag deep dehydration system and method based on microwave vacuum cooperation drying, and relates to the technical field of solid waste resource treatment. The method comprises five steps of feeding, establishing a vacuum environment, microwave grading dehydration, steam-water separation and condensation recovery, and discharging. The microwave grading dehydration adopts a three-level control strategy based on the water content of the material, corresponding to the first, second and third control strategies and mathematical models. The application realizes deep dehydration under low-temperature conditions through the synergistic effect of internal rapid heating by microwaves and reduction of water boiling point by vacuum, and can reduce the water content of the gasification fine slag from 80%-99% to below 15% at one time, and has the advantages of high dehydration depth, fast speed, low energy consumption, environmental friendliness and the like.

Description

Technical Field

[0001] This invention relates to the field of solid waste resource utilization technology, and in particular to a deep dehydration system and method for gasification fine slag based on microwave vacuum synergistic drying, which is especially suitable for the deep dehydration treatment of high-moisture-content gasification fine slag generated during coal gasification. Background Technology

[0002] Gasification slag is a solid waste generated during coal gasification production, primarily originating from black water and ash water treatment systems. In 2025, my country's total energy consumption was approximately 5.96 billion tons of standard coal equivalent, of which about 600 million tons were used for coal chemical production, generating approximately 60 million tons of gasification slag solid waste annually, with a moisture content as high as 55%. The high-moisture-content gasification slag is treated using traditional landfill methods, which wastes water resources, lacks resource utilization, and pollutes the environment.

[0003] Gasification ash is characterized by its porous structure, small particle size, and high internal moisture content, making dewatering and drying difficult. Previous designs typically employed common dewatering equipment and processes such as vacuum belt filters, plate and frame filter presses, and centrifuges, but these methods proved ineffective, resulting in filter cakes with high moisture content (approximately 50%). To further reduce the moisture content of the ash, existing technologies have attempted to use horizontal screw centrifuges for dewatering. Under centrifugal force, horizontal screw centrifuges are more efficient at separating moisture than belt vacuum filters. However, since no phase change occurs during dewatering, it is difficult to further remove moisture from the pores of the ash. Another approach is to use conventional plate and frame filter presses. For example, patent application number 2020227879526 discloses a plate and frame filter press composed of alternating filter plates and frames. Filter cloth is wrapped around the sides of the frames, and the ends are fixed with clamps. Both plates and frames have grooves connecting to the mud inlet holes, forming conduits. During filtration, a pump forces the slurry into the machine through a conduit, directing it into each filter frame space. The filtrate passes through the filter cloth, collects along the grooves of the filter plates, and is discharged through a drain pipe, while the filter cake remains inside the frame. After each operation is completed, the filter press automatically pulls open the root plate to unload the filter cake. However, this type of equipment can generally only reduce the moisture content to around 45%, and it is difficult to reduce it further.

[0004] In addition, there are heated vacuum plate and frame filter presses that combine technologies from vacuum belt filter presses, plate and frame filter presses, and steam drying. For example, patent application number 201821789705.6 discloses a system for deep dewatering of coal gasification filter cake; patent application number 201210045436.3 discloses a low-temperature vacuum dewatering and drying equipment and its process, which uses hot water to heat the material inside the plate and frame filter press while simultaneously applying a vacuum to reduce the moisture content. Low-pressure steam is generally used for heating. This method has a good dewatering effect and can effectively remove moisture from the material, but it consumes a lot of energy and is not economically viable.

[0005] In summary, the problems with the existing technologies mentioned above include: the moisture content after dehydration is still as high as 30%-50%, which cannot meet the requirements for resource utilization; the high moisture content filter cake is difficult to transport, pollutes the environment, and poses safety hazards to the slag yard; water resources are wasted seriously; energy consumption is high, equipment is complex, and economic efficiency is poor.

[0006] Therefore, developing a high-efficiency, energy-saving, and deep dehydration drying technology has become an urgent technical challenge in the field of coal chemical solid waste resource utilization. To this end, a deep dehydration system and method for gasified fine slag based on microwave vacuum synergistic drying is proposed. Summary of the Invention

[0007] The main objective of this invention is to provide a deep dehydration system and method for gasified fine slag based on microwave vacuum synergistic drying, which can effectively solve the problems in the background art.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] In a first aspect, the present invention provides a method for deep dehydration of gasified fine slag based on microwave vacuum synergistic drying, comprising the following steps:

[0010] Step S1: The material to be dehydrated is transported into the sealed cavity of the microwave vacuum drying host;

[0011] Step S2: Evacuate the sealed cavity to create a vacuum environment, reducing its absolute pressure to 0.01-0.04 MPa, so that the dehydration temperature of the material is controlled within the range of 30-80°C.

[0012] Step S3: Apply microwaves with a frequency of 2.45 GHz ± 25 MHz to the material, and automatically adjust the microwave power density according to the real-time moisture content of the material to implement graded dehydration control;

[0013] Step S4: The water vapor generated by evaporation in step S3 is extracted through a vacuum system, condensed into liquid water by a condenser, and then recovered.

[0014] Step S5: When the moisture content of the material decreases below the preset threshold, stop the microwave and vacuum systems and unload the dried material.

[0015] Specifically:

[0016] In step S3, the graded dehydration control includes a free water removal stage, a capillary bound water removal stage, and an internal bound water removal stage.

[0017] The free water removal stage specifically includes:

[0018] When the moisture content of the material is greater than At that time, the first control strategy is used to adjust the first microwave power density. The unit is W / g, expressed as: ,in Maximum safe microwave power density, expressed in W / g; This is the upper limit temperature for the first stage, in °C. This is the lower limit temperature for the first stage, in °C. Let t be the temperature at time t; This represents the initial moisture content. Let t be the moisture content at time t.

[0019] Preferred, The temperature is set at 70℃. The temperature is set at 40℃. It is 40%; The value range is [15, 20].

[0020] The capillary water removal stage specifically includes:

[0021] When the moisture content of the material is between When the range is reached, the second control strategy is used to adjust the second microwave power density. The unit is W / g, expressed as: ,in The power density is the reference value, expressed in W / g. This is the temperature regulation coefficient, dimensionless. This is the boiling point of water under the current pressure, expressed in °C.

[0022] Preferred, The value range is [8, 12]; The value range is [0.01, 0.05]; It is 20%.

[0023] The internal bound water removal stage specifically includes:

[0024] When the moisture content of the material is less than At that time, a third control strategy of intermittent microwave irradiation is adopted to adjust the third microwave power density. The unit is W / g, expressed as: ,in Low power density, measured in W / g; irradiation duty cycle for: .

[0025] Preferred, The value range is [5, 8];

[0026] The absolute pressure of the vacuum environment Within the range of 0.01 to 0.04 MPa, the vacuum environment causes the boiling point of water to be lower than the current pressure. Satisfies the Clausius-Clapeyron equation: ,in Standard boiling point, in °C; is the gas constant, with units of J / (mol·K); This represents the molar mass of water, expressed in kg / mol. Standard atmospheric pressure It is the latent heat of vaporization of water.

[0027] Volumetric heat source term for microwave heating The following electromagnetic field and heat source coupling equations must be satisfied: ,in Electric field strength; The electrical conductivity of the material; It is a microwave frequency; It is the vacuum permittivity; is the dielectric loss factor of the material.

[0028] The dehydration process of the material is controlled by the following heat transfer equation: ,in The effective volumetric heat capacity of the material; For effective thermal conductivity; The denoted factor is the rate of water evaporation.

[0029] The rate of water evaporation Determined through the following model: ,in This is the evaporation rate constant; This refers to the volume fraction of liquid water. The density of liquid water; This is an empirical index, with a value range of (1,2).

[0030] The microwave power is adjusted using a closed-loop adaptive control strategy, dynamically adjusting the output power based on the following moisture content prediction model: ,in for Predicted moisture content at time; The microwave energy utilization efficiency is defined as [0.6, 0.9]. This refers to the dry basis density of the material. To control the cycle;

[0031] When the predicted moisture content is lower than the target value, the microwave power is cut off to prevent over-drying and heat loss.

[0032] Preferably, the staged dehydration control also includes safety control constraints:

[0033] like or If so, the microwave generator will be forcibly shut down.

[0034] Secondly, the present invention provides a deep dewatering system for gasified fine slag based on microwave vacuum synergistic drying, used to implement the above-mentioned deep dewatering method for gasified fine slag based on microwave vacuum synergistic drying, comprising:

[0035] The feeding unit includes a buffer tank 2 and a feed pump 3. The inlet of the buffer tank 2 receives the material to be dewatered, and the outlet of the buffer tank 2 is connected to the inlet of the feed pump 3 for intermittently conveying the material to the dewatering host.

[0036] Microwave vacuum drying unit 5 includes:

[0037] Sealing cover 17 forms a sealed processing cavity;

[0038] Multiple filter plates 16 are disposed inside the sealing cover 17 for carrying materials and performing pressure filtration and dewatering;

[0039] Multiple microwave generators 18 are disposed on the upper part of the sealing cover 17 for applying microwave energy to the material inside the sealed cavity;

[0040] A microwave receiver 19 is disposed at the lower part of the sealing cover 17 and is used to absorb the residual microwaves that penetrate the material;

[0041] Vacuum system 12 is connected to the sealed cavity of the microwave vacuum drying host 5 and is used to evacuate the cavity to reduce its absolute pressure to 0.01-0.04 MPa.

[0042] A condensation recovery system, connected to the outlet of the vacuum system 12, includes a condenser and a filter tank 9, for condensing evaporated water vapor into condensate 8 and recovering it;

[0043] The unloading unit, including the unloading belt 15, is located below the microwave vacuum drying host 5 and is used to output the dried material.

[0044] The system includes an intelligent control system, which is connected to the feed pump 3, microwave generator 18, vacuum system 12, and condensation recovery system, respectively. This system is used to automatically adjust the microwave power and vacuum level based on the online monitoring of the material's moisture content and temperature, thereby achieving graded dehydration control.

[0045] Specifically:

[0046] The workflow of the deep dehydration system for gasified fine residue based on microwave vacuum synergistic drying is as follows:

[0047] Feeding stage: The water-containing gasified fine slag 1 continuously enters the buffer tank 2. The feed pump 3 is used to transport the fine slag to the microwave vacuum drying host 5. The pump-pressurized feed solids are left in the cavity between the filter plates 16, and the water passes through the filter cloth to form filtrate 14 which enters the filtrate tank 9.

[0048] Dehydration stage: After feeding is completed, the vacuum system is started and the microwave generator is started at the same time. According to the changes in the online water content of the fine residue, the microwave power is automatically adjusted in real time using the above method. The water in the gasified fine residue boils out and is separated into gas and liquid by condensation in the vacuum system. The condensate 8 enters the filter tank 9 and the vacuum air is discharged.

[0049] Unloading stage: When the moisture content of the material meets the performance requirements (e.g., ≤15%), stop the microwave and vacuum system, the dehydration process ends, then open the lower part of the sealing cover 17, the main unit opens the plate to unload the material, and the dry material is transported out for use using the unloading belt 15.

[0050] Beneficial effects

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] The method proposed in this invention can reduce the moisture content of gasification slag from 80%-99% to below 15% in one step, which is better than the approximately 30% of the prior art;

[0053] The microwave-vacuum synergistic effect proposed in this invention reduces drying time by 50%-70%, which is 5-10 times faster than traditional hot air drying.

[0054] The method proposed in this invention reduces energy consumption per unit of water evaporation by more than 30%, and achieves a thermal efficiency of 85%-90%.

[0055] The method proposed in this invention uses low-temperature drying (≤60℃) to avoid residual carbon oxidation loss, and the calorific value retention rate is ≥95%.

[0056] The system proposed in this invention is a fully enclosed system with no dust spillage and a condensate recovery rate of ≥90%.

[0057] The system proposed in this invention has low equipment modification costs and can technically upgrade existing plate and frame filter presses by simply adding a microwave generator and a vacuum pumping device. Attached Figure Description

[0058] Figure 1 This is a schematic diagram of the process for the deep dehydration method of gasified fine slag based on microwave vacuum synergistic drying according to the present invention.

[0059] Figure 2 This is a schematic diagram of the structure of the gasification fine slag deep dehydration system based on microwave vacuum synergistic drying according to the present invention;

[0060] Figure 3 This is a schematic diagram of the installation structure of the microwave generator and microwave receiver in the system of the present invention.

[0061] In the diagram, 1: Water-containing gasified fine residue; 2: Buffer tank; 3: Feed pump; 4: Microwave generator; 5: Microwave vacuum drying host; 6: Plate and frame; 7: Vacuum exhaust; 8: Condensate; 9: Filtrate tank; 10: Filtrate; 11: Filtrate recovery; 12: Vacuum condensation system; 13: Residual liquid backflushing; 14: Filtrate; 15: Discharge belt; 16: Filter plate; 17: Sealing cover; 18: Microwave generator; 19: Microwave receiver. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0063] Example 1:

[0064] This embodiment provides a deep dehydration method that combines microwave heating and vacuum drying, specifically including the following steps:

[0065] Step 1, Feeding

[0066] The gasification slag from a coal chemical plant has an initial moisture content of 85%. The material continuously enters the buffer tank 2 and is then transported by the feed pump 3 to the plate and frame cavity 6 of the microwave vacuum drying host 5. During the feeding process, free water passes through the filter cloth to form filtrate 14, which enters the filtrate tank 9.

[0067] Step 2, establish a vacuum environment

[0068] Start the vacuum condensation system 12 to reduce the absolute pressure inside the main unit cavity to 0.02 MPa (gauge pressure -0.08 MPa). At this point, the boiling point of water is... Satisfies the Clausius-Clapeyron equation: ,in Standard boiling point, in °C; is the gas constant, with units of J / (mol·K); This represents the molar mass of water, expressed in kg / mol. Standard atmospheric pressure It is the latent heat of vaporization of water.

[0069] In this embodiment, when the absolute pressure inside the main unit cavity drops to 0.02 MPa, the boiling point of water is... It dropped to about 60°C.

[0070] Step 3, microwave graded heating dehydration

[0071] Microwave generator 18 is activated, applying microwaves at a frequency of 2.45 GHz. Based on online moisture content monitoring data, a three-stage dehydration control system is implemented, including:

[0072] The first stage (moisture content > 40%), i.e., the free water removal stage: the first control strategy is used to adjust the first microwave power density. The unit is W / g, expressed as: ,in Maximum safe microwave power density, expressed in W / g; This is the upper limit temperature for the first stage, in °C. This is the lower limit temperature for the first stage, in °C. Let t be the temperature at time t; This represents the initial moisture content. Let t be the moisture content at time t.

[0073] In this embodiment, P max =18 W / g, upper temperature limit 70℃, duration 15 minutes.

[0074] The second stage (moisture content 20%-40%), namely the capillary water removal stage: A second control strategy is used to adjust the second microwave power density. The unit is W / g, expressed as: ,in The power density is the reference value, expressed in W / g. This is the temperature regulation coefficient, dimensionless. This is the boiling point of water under the current pressure, expressed in °C.

[0075] In this embodiment, P mid =10 W / g, α=0.03, lasting for 10 minutes.

[0076] The third stage (moisture content <20%), namely the internal bound water removal stage: a third control strategy using intermittent microwave irradiation is employed to adjust the third microwave power density. The unit is W / g, expressed as: ,in Low power density, measured in W / g; irradiation duty cycle for: .

[0077] In this embodiment, P low =6 W / g, γ=0.4, intermittent irradiation (5 seconds on / 5 seconds off), for 8 minutes.

[0078] Among them, the volumetric heat source item of microwave heating The following electromagnetic field and heat source coupling equations must be satisfied: ,in Electric field strength; The electrical conductivity of the material; It is a microwave frequency; It is the vacuum permittivity; is the dielectric loss factor of the material.

[0079] In this embodiment, the material temperature is maintained within the range of 50-65℃ through closed-loop control. Specifically:

[0080] The dehydration process of the material is controlled by the following heat transfer equation: ,in The effective volumetric heat capacity of the material; For effective thermal conductivity; The denoted factor is the rate of water evaporation.

[0081] Water evaporation rate Determined through the following model: ,in This is the evaporation rate constant; This refers to the volume fraction of liquid water. The density of liquid water; This is an empirical index, with a value range of (1,2).

[0082] The microwave power is adjusted using a closed-loop adaptive control strategy, dynamically adjusting the output power based on the following moisture content prediction model: ,in for Predicted moisture content at time; The microwave energy utilization efficiency is defined as [0.6, 0.9]. This refers to the dry basis density of the material. To control the cycle;

[0083] When the predicted moisture content is lower than the target value, the microwave power is cut off to prevent over-drying and heat loss.

[0084] Automatic power reduction or shutdown when safety control constraints are triggered. The safety control constraints are: If or If so, the microwave generator will be forcibly shut down.

[0085] Step 4, vapor-liquid separation and condensation recovery

[0086] The water vapor produced by evaporation is extracted through a vacuum system, condensed into condensate 8 by a condenser, and then recycled into a filter tank 9. Non-condensable gas (vacuum air 7) is discharged.

[0087] Step 5, Discharge

[0088] When the moisture content of the material drops to 12%, the microwave and vacuum systems are stopped, the main unit opens to unload the material, and the dried material is transported away via unloading conveyor belt 15.

[0089] In this embodiment, the dried material has a moisture content of 12%, a calorific value retention rate of 96.5%, a condensate recovery rate of 92%, and a unit energy consumption that is 35% lower than that of traditional heat drying.

[0090] Example 2:

[0091] This embodiment is basically the same as Embodiment 1, except that:

[0092] Initial moisture content: 92%

[0093] Absolute vacuum pressure: 0.015 MPa

[0094] Staged dehydration control parameters:

[0095]

[0096] Results: After drying, the moisture content was 14%, the calorific value retention rate was 95.2%, the condensate recovery rate was 91%, and the unit energy consumption was reduced by 32%.

[0097] Example 3:

[0098] This embodiment provides an example of modifying an existing plate and frame filter press into the method of the present invention.

[0099] Existing equipment: conventional plate and frame filter press, with a moisture content of approximately 45% after dewatering.

[0100] Renovation plan:

[0101] Microwave generators 18 with a power of 15 kW were added to both ends of the main board frame;

[0102] A vacuum pumping device is added in reverse to the filtrate pipeline, along with a condenser;

[0103] A PLC + touch screen intelligent control system is added to realize online monitoring of moisture content and adaptive power adjustment.

[0104] Results: After the modification, the moisture content after dehydration was reduced to 13%, and the processing cycle was shortened from 8 hours to 3 hours.

[0105] This invention provides a deep dehydration method that combines microwave heating and vacuum drying, which can be widely applied to:

[0106] Deep dehydration treatment of fine slag from coal chemical gasification;

[0107] Dewatering and drying of municipal and industrial sludge;

[0108] Low-temperature drying in the food, pharmaceutical, and chemical industries;

[0109] Energy-saving retrofitting of existing plate and frame filter presses.

[0110] This invention has the advantages of high dehydration depth, fast speed, low energy consumption, environmental friendliness, and low equipment modification cost, and has good industrial application prospects and promotion value.

[0111] Example 3:

[0112] The present invention also provides a deep dewatering system for gasified fine slag based on microwave vacuum synergistic drying, which can be deployed in actual production processes, comprising:

[0113] The feeding unit includes a buffer tank 2 and a feed pump 3. The inlet of the buffer tank 2 receives the material to be dewatered, and the outlet of the buffer tank 2 is connected to the inlet of the feed pump 3 for intermittently conveying the material to the dewatering host.

[0114] Microwave vacuum drying unit 5 includes:

[0115] Sealing cover 17 forms a sealed processing cavity;

[0116] Multiple filter plates 16 are disposed inside the sealing cover 17 for carrying materials and performing pressure filtration and dewatering;

[0117] Multiple microwave generators 18 are disposed on the upper part of the sealing cover 17 for applying microwave energy to the material inside the sealed cavity;

[0118] A microwave receiver 19 is disposed at the lower part of the sealing cover 17 and is used to absorb residual microwaves that penetrate the material.

[0119] Vacuum system 12 is connected to the sealed cavity of microwave vacuum drying host 5 and is used to evacuate the cavity to reduce its absolute pressure to 0.01-0.04 MPa.

[0120] A condensation recovery system, connected to the outlet of vacuum system 12, includes a condenser and a filter tank 9, for condensing evaporated water vapor into condensate 8 and recovering it;

[0121] The unloading unit, including the unloading belt 15, is located below the microwave vacuum drying host 5 and is used to output the dried material.

[0122] The system includes an intelligent control system, which is connected to the feed pump 3, microwave generator 18, vacuum system 12, and condensation recovery system. This system automatically adjusts the microwave power and vacuum level based on the online monitoring of the material's moisture content and temperature to achieve graded dehydration control.

[0123] Specifically, the system's workflow is as follows:

[0124] Feeding stage: The water-containing gasified fine slag 1 continuously enters the buffer tank 2. The feed pump 3 is used to transport the fine slag to the microwave vacuum drying host 5. The pump-pressurized feed solids are left in the cavity between the filter plates 16, and the water passes through the filter cloth to form filtrate 14 which enters the filtrate tank 9.

[0125] Dehydration stage: After feeding is completed, the vacuum system is started and the microwave generator is started at the same time. According to the changes in the online water content of the fine residue, the microwave power is automatically adjusted in real time using the above method. The water in the gasified fine residue boils out and is separated into gas and liquid by condensation in the vacuum system. The condensate 8 enters the filter tank 9 and the vacuum air is discharged.

[0126] Unloading stage: When the moisture content of the material meets the performance requirements (e.g., ≤15%), stop the microwave and vacuum system, the dehydration process ends, then open the lower part of the sealing cover 17, the main unit opens the plate to unload the material, and the dry material is transported out for use using the unloading belt 15.

[0127] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for deep dehydration of gasified fine slag based on microwave vacuum synergistic drying, characterized in that, Includes the following steps: S1: The material to be dehydrated is transported into the sealed cavity of the microwave vacuum dryer; S2: Evacuate the sealed cavity to create a vacuum environment, reducing its absolute pressure to 0.01-0.04 MPa, so that the dehydration temperature of the material is controlled within the range of 30-80℃. S3: Apply microwaves with a frequency of 2.45 GHz ± 25 MHz to the material, and automatically adjust the microwave power density according to the real-time moisture content of the material to implement graded dehydration control. The graded dehydration control includes a free water removal stage, a capillary bound water removal stage, and an internal bound water removal stage. S4: The water vapor generated by evaporation in step S3 is extracted through a vacuum system, condensed into liquid water by a condenser, and then recovered. S5: When the moisture content of the material drops below the preset threshold, stop the microwave and vacuum systems and unload the dried material.

2. The method for deep dehydration of gasified fine slag based on microwave vacuum synergistic drying according to claim 1, characterized in that, The free water removal stage specifically includes: When the moisture content of the material is greater than At that time, the first control strategy is used to adjust the first microwave power density. , is represented as: ,in For maximum safe microwave power density; This is the upper limit temperature for the first stage; This is the lower limit temperature for the first stage; Let t be the temperature at time t; This represents the initial moisture content. Let t be the moisture content at time t.

3. The method for deep dehydration of gasified fine slag based on microwave vacuum synergistic drying according to claim 1, characterized in that, The capillary water removal stage specifically includes: When the moisture content of the material is between When the range is reached, the second control strategy is used to adjust the second microwave power density. , is represented as: ,in Power density as a reference; This is the temperature regulation coefficient; This is the boiling point of water under the current pressure.

4. The method for deep dehydration of gasified fine slag based on microwave vacuum synergistic drying according to claim 1, characterized in that, The internal bound water removal stage specifically includes: When the moisture content of the material is less than At that time, a third control strategy of intermittent microwave irradiation is adopted to adjust the third microwave power density. , is represented as: ,in For low power density; irradiation duty cycle for: .

5. The method for deep dehydration of gasified fine slag based on microwave vacuum synergistic drying according to any one of claims 1-4, characterized in that, The absolute pressure of the vacuum environment Within the range of 0.01 to 0.04 MPa, the vacuum environment causes the boiling point of water to be lower than the current pressure. Satisfies the Clausius-Clapeyron equation: ,in Standard boiling point; It is the gas constant; The molar mass of water; Standard atmospheric pressure It is the latent heat of vaporization of water.

6. The method for deep dehydration of gasified fine slag based on microwave vacuum synergistic drying according to any one of claims 1-4, characterized in that, In step S3, the volumetric heat source term of microwave heating The following electromagnetic field and heat source coupling equations must be satisfied: ,in Electric field strength; The electrical conductivity of the material; It is a microwave frequency; It is the vacuum permittivity; is the dielectric loss factor of the material.

7. The method for deep dehydration of gasified fine slag based on microwave vacuum synergistic drying according to any one of claims 1-4, characterized in that, In step S3, the dehydration process of the material is controlled by the following heat transfer equation: ,in The effective volumetric heat capacity of the material; For effective thermal conductivity; This represents the rate of water evaporation.

8. The method for deep dehydration of gasified fine slag based on microwave vacuum synergistic drying according to claim 7, characterized in that, The rate of water evaporation Determined through the following model: ,in This is the evaporation rate constant; This refers to the volume fraction of liquid water. The density of liquid water; This is an empirical index, with a value range of (1,2).

9. The method for deep dehydration of gasified fine slag based on microwave vacuum synergistic drying according to any one of claims 1-4, characterized in that, In step S3, the microwave power is adjusted using a closed-loop adaptive control strategy, dynamically adjusting the output power based on the following moisture content prediction model: ,in for Predicted moisture content at time; The microwave energy utilization efficiency is defined as [0.6, 0.9]. This refers to the dry basis density of the material. To control the cycle; When the predicted moisture content is lower than the target value, the microwave power is cut off to prevent over-drying and heat loss.

10. A deep dewatering system for gasified fine slag based on microwave vacuum synergistic drying, used to implement the deep dewatering method for gasified fine slag based on microwave vacuum synergistic drying as described in any one of claims 1-9, characterized in that, include: The feeding unit includes a buffer tank (2) and a feed pump (3). The inlet of the buffer tank (2) receives the material to be dewatered, and the outlet of the buffer tank (2) is connected to the inlet of the feed pump (3) for intermittently conveying the material to the dewatering host. Microwave vacuum drying host (5) includes: The sealing cover (17) forms a sealed processing cavity; Multiple filter plates (16) are disposed inside the sealing cover (17) for carrying materials and performing pressure filtration and dewatering; Multiple microwave generators (18) are disposed on the upper part of the sealing cover (17) for applying microwave energy to the material inside the sealed cavity; A microwave receiver (19) is disposed at the lower part of the sealing cover (17) for absorbing residual microwaves that penetrate the material; Vacuum system (12), connected to the sealed cavity of the microwave vacuum drying host (5), is used to evacuate the cavity and reduce its absolute pressure to 0.01-0.04 MPa; A condensation recovery system, connected to the outlet of the vacuum system (12), includes a condenser and a filter tank (9) for condensing evaporated water vapor into condensate (8) and recovering it; The unloading unit, including the unloading belt (15), is located below the microwave vacuum drying host (5) and is used to output the dried material; The intelligent control system is connected to the feed pump (3), microwave generator (18), vacuum system (12) and condensation recovery system respectively, and is used to automatically adjust the microwave power and vacuum degree according to the material moisture content and temperature monitored online, so as to realize the graded dehydration control.

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