Method and apparatus for simultaneous dewatering and desulfurization of solid sludge and production of solid fuel

Abstract

This invention belongs to the field of sludge treatment technology, specifically a method and equipment for reducing the moisture content of solid sludge, simultaneously desulfurizing it, and preparing solid fuel. The method includes steps such as solid sludge pretreatment, solid sludge moisture content reduction treatment, dry sludge turning and ventilation treatment, dry sludge solid fuel preparation, and solid fuel packaging. This method differs from natural drying, mechanical dehydration, and thermal drying technologies by utilizing vacuum technology to rapidly reduce moisture content. The vacuum-enclosed operation generates no dust and enables rapid desulfurization under vacuum conditions, forming a complete solid sludge treatment production line, which contributes to the development of green industrial technologies. The equipment includes a material conveying channel, a homogenizing and dispersing device, a vacuum dryer, a vacuum station, a cooler, a conveyor belt, and a pelletizing machine, forming a solid sludge treatment production line with a high degree of automation. The low-energy equipment achieves efficient moisture content reduction, achieving a balance between treatment efficiency and cost.

Description

Technical Field

[0001] This invention belongs to the field of sludge treatment technology. Specifically, it is a method and equipment for reducing the moisture content of solid sludge, simultaneously desulfurizing it, and preparing solid fuel. It is mainly used to treat solid sludge with a moisture content of less than 80%. Background Technology

[0002] Existing sludge treatment methods mainly include natural drying, mechanical dewatering, and thermal drying. Natural drying removes water through evaporation and osmosis, offering lower costs, but requires a large area, is limited by climate conditions, has a long drying cycle, and is prone to producing foul odors and environmental pollution. Mechanical dewatering uses mechanical force to compress and dewater the sludge; common methods include belt filter presses and plate and frame filter presses. While offering high dewatering efficiency, it consumes a lot of energy, suffers from severe equipment wear, and has high operating and maintenance costs. Thermal drying technology achieves high drying efficiency by heating the sludge to evaporate water, but it consumes enormous amounts of energy and has high operating costs. However, these methods have several significant problems. First, natural drying is inefficient and cannot meet the efficiency and environmental requirements of modern sludge treatment. Second, while mechanical dewatering has high dewatering efficiency, its high energy consumption and high operating costs limit its application. Third, although thermal drying technology has high drying efficiency, its operating costs and energy consumption limit its practical application.

[0003] Furthermore, sludge contains a large amount of sulfur, which (usually in the form of sulfides, sulfates, and organic sulfur) can cause numerous harms to the soil and surrounding environment through physical, chemical, and biological processes if directly discharged (such as through indiscriminate dumping, landfilling, mixing into soil, or incineration). These harms include soil acidification, damage to soil structure, disruption of soil nutrient balance, inhibition of microbial activity, pollution of surface and groundwater, and atmospheric pollution from incineration. Therefore, before sludge is discharged or utilized for resource recovery, its sulfur content must be reduced through desulfurization processes (such as oxidative desulfurization and biological desulfurization). This is a crucial step in ensuring soil safety and protecting the ecological environment.

[0004] Currently, patent application number 202411945359.6 (publication number CN119371076A), entitled "A Low-Energy Sludge High-Dry Dewatering and Low-Temperature Drying System and Control Method Thereof," discloses a low-energy sludge high-dry dewatering and low-temperature drying control method. This method discloses steps such as sludge pretreatment, sludge conveying, sludge vacuum dewatering, and dry sludge conveying and storage. The method involves pumping wastewater in a completely liquid state mixed with sludge into a sludge tank to start the entire treatment process. This method can solve the technical problems faced by natural drying, mechanical dewatering, and thermal drying technologies. However, this method does not disclose how to remove sulfur substances from the sludge, and cannot solve the technical problem that sludge still pollutes the environment due to sulfur after dewatering.

[0005] Furthermore, sludge is generally classified into liquid sludge (flowing slurry with a water content of 95%–99.5%), semi-solid sludge (viscous paste or ointment with a water content of 90%–95%), solid sludge (lumpy and non-flowing with a water content of 60%–80%), and dry solid sludge (water content <60%, even as low as 10%, granular, powdery, or fragmented, with a hard texture). The technology described in "A Low-Energy Sludge High-Dryness Dewatering and Low-Temperature Drying System and Its Control Method" primarily treats "liquid sludge." In contrast, this technology mainly targets the treatment of solid sludge and dry solid sludge, addressing the technical challenges of reducing the moisture content and removing sulfur compounds from solid sludge to produce environmentally friendly solid fuel, thus forming a complete process chain. Summary of the Invention

[0006] This invention aims to provide a method and equipment for reducing the moisture content of solid sludge, simultaneously desulfurizing it, and preparing solid fuel. This method differs from technologies such as natural drying, mechanical dehydration, and thermal drying. It utilizes vacuum technology to rapidly reduce the moisture content, and the vacuum-closed operation generates no dust. Furthermore, it rapidly desulfurizes under vacuum conditions, forming a complete solid sludge treatment production line, which helps promote the development of green industrial technologies.

[0007] To achieve the above objectives, a method for reducing the moisture content of solid sludge, simultaneously desulfurizing it, and preparing solid fuel includes the following steps:

[0008] S1. Solid sludge pretreatment: Solid sludge with a moisture content of less than 80% is conveyed to the homogenizing and dispersing device through the material conveying channel. The homogenizing and dispersing device crushes the solid sludge into uniformly sized particles. Desulfurizing agent is added to the solid sludge according to a predetermined ratio through an automatic dosing device. The solid sludge is crushed and stirred into honeycomb particles.

[0009] S2. Solid sludge moisture content reduction treatment: The pretreated solid sludge is discharged from the homogenizing mixer and disperser onto the conveyor belt and spread out. The conveyor belt slowly passes through the vacuum dryer under continuous vacuum to dry the solid sludge, leaching the moisture from the solid sludge surface.

[0010] S3. Dry sludge turning and ventilation treatment: The conveyor belt runs continuously and carries the vacuum-dried dry sludge through the air cooler. The conveyor belt turning and the air cooler work alternately to quickly evaporate the moisture on the surface of the dry sludge.

[0011] S4. Preparation of solid fuel from dry sludge: Dry sludge with a moisture content reduced to 20% to 25% is transported to a pelletizing machine, which then forms honeycomb-shaped solid fuel from the dry sludge.

[0012] S4. Solid fuel baling: Solid fuel is transported to the baling machine, where it is baled and stored.

[0013] Furthermore, the mixing ratio of solid sludge and desulfurizing agent in the homogenizing mixer is 3% to 7%.

[0014] Furthermore, after the solid sludge enters the homogenizing and dispersing unit, the homogenizing and dispersing unit stirs and desulfurizes the solid sludge under vacuum and low pressure.

[0015] Furthermore, when the homogenizing mixer and vacuum dryer are working, a data detector is activated to detect the vacuum level, which is used to control the working frequency of the vacuum station.

[0016] Furthermore, after the sulfur content of the solid sludge in the homogenizing mixer is reduced to below 1%, it is transported to the vacuum dryer.

[0017] Furthermore, the homogenizing mixer and vacuum dryer are connected to an external buffer tank, which is used to recover the sulfur-containing mixture gaseous water under vacuum negative pressure.

[0018] Furthermore, the solid sludge is dyeing and printing sludge or biological sludge.

[0019] Equipment for reducing the moisture content of solid sludge, simultaneously desulfurizing it, and preparing solid fuel; and methods for achieving the above-mentioned reduction of the moisture content of solid sludge, simultaneously desulfurizing it, and preparing solid fuel, including:

[0020] Material conveying channel, a closed channel structure, used to convey solid sludge into the homogenizing and dispersing device;

[0021] The homogenizing and dispersing device is a tilting tank structure, equipped with one or more sets, and includes a stirring and cutting blade assembly and a dispersion and homogenization assembly.

[0022] A vacuum dryer, installed downstream of a homogenizing and dispersing unit, is used to dry solid sludge exiting the homogenizing and dispersing unit.

[0023] The vacuum station is externally connected to a vacuum negative pressure pipeline and is linked to a homogenizing mixer and a vacuum dryer.

[0024] A cool air blower, installed downstream of the vacuum station, is used to dry the surface moisture of the solid sludge.

[0025] The conveyor belt, divided into multiple sections, connects to the homogenizing mixer, vacuum dryer, and air cooler, forming a solid sludge transfer line.

[0026] There is one or more pellet forming machines, installed downstream of the last air cooler.

[0027] Furthermore, the conveyor belts between the vacuum dryer and the air cooler, and between the air coolers, are arranged in upper and lower sections, with the upper and lower conveyor belts having different transmission directions, and the lower conveyor belt receiving the solid sludge on the upper conveyor belt.

[0028] Furthermore, it also includes a baling machine and a buffer tank. The baling machine is installed at the discharge end of multiple pellet forming machines, and the buffer tank is installed on the vacuum negative pressure port of the homogenizing mixer and vacuum dryer. The buffer tank is equipped with a decomposition device for decomposing hydrogen sulfide.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] 1. Effectively solves the problem of sulfur pollution in sludge and achieves environmentally friendly treatment: This technology reduces the sulfur content of solid sludge to below 1% by adding desulfurizing agent in the pretreatment stage, combined with the mixing effect of homogenization and high-pressure vacuum control. This overcomes the shortcomings of existing sludge treatment technologies (such as natural drying and mechanical dewatering) that do not involve desulfurization treatment, which leads to soil and atmosphere pollution when sludge is subsequently stored or incinerated. It blocks the harm of sulfur to the ecological environment from the source.

[0031] 2. Low energy consumption achieves high efficiency in reducing moisture content, balancing treatment efficiency and cost: The process adopts a synergistic process of vacuum drying combined with material turning and ventilation. The vacuum environment is used to leach out moisture and the cold air fan accelerates surface evaporation, reducing the moisture content of solid sludge from 60% to 80% to 20% to 25%, which significantly reduces energy consumption compared to traditional thermal drying technology. At the same time, the entire process is linked by automated equipment such as conveyor belts and automatic dosing, avoiding the long cycle and climate limitations of natural drying, thus controlling operating costs while ensuring treatment efficiency.

[0032] 3. Realize the resource utilization of sludge and turn waste into treasure: Through a complete process chain, the treated dry sludge is made into solid fuel. This not only utilizes the calorific value retention effect of processes such as vacuum drying (which meets the goal of "preserving the internal calorific value of materials" in sludge treatment), but also improves the environmental friendliness of the fuel through desulfurization treatment. This solves the limitation of traditional sludge treatment, which only focuses on volume reduction and harmlessness without realizing resource utilization, and opens up a usable path for sludge to be used as solid fuel.

[0033] 4. The solid sludge treatment line operates with a high degree of automation. The material is thoroughly cut and broken into small volumes by a mixer, exposing the encapsulated moisture. Then, high-vacuum equipment is used to leach the internal moisture from the sludge surface, allowing it to evaporate naturally and quickly, thus producing granules. The entire production process generates no dust, wastewater, or other emissions, while fully preserving the internal calorific value of the material, achieving volume reduction, harmlessness, and resource utilization. Attached Figure Description

[0034] Figure 1 A schematic diagram of the process flow for reducing the moisture content of solid sludge, simultaneously desulfurizing it, and preparing solid fuel.

[0035] Figure 2Diagram of an integrated upper and lower layer structure for a vacuum dryer / conveyor belt and air cooler;

[0036] Figure 3 This is a front view of a homogenizing mixer / dispersor.

[0037] Figure 4 This is a left-side view of the structure of a uniform stirring disperser. Detailed Implementation

[0038] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention.

[0039] like Figure 1 — Figure 4 A method for reducing the moisture content of solid sludge, simultaneously desulfurizing it, and preparing solid fuel includes the following steps:

[0040] S1. Solid sludge pretreatment: Solid sludge with a moisture content of less than 80% is conveyed to a homogenizing and dispersing device through a material conveying channel. The homogenizing and dispersing device crushes the solid sludge into uniformly sized particles, fully exposing the encapsulated moisture. Desulfurizing agent is added to the solid sludge according to a predetermined ratio through an automatic dosing device, and the solid sludge is crushed and stirred into honeycomb particles.

[0041] The mixing ratio of solid sludge and desulfurizing agent in the homogenizing mixer is 3% to 7%. When the sulfur content is between 4.2 and 4.8, the maximum dosage of desulfurizing agent should be added, and the mixing ratio of the two should reach the highest of 7%.

[0042] Desulfurizing agents can be strong oxygen-generating agents such as calcium hydroxide, sulfuric acid, and hydrochloric acid. They utilize acidification chemical treatment technology to treat sulfur-containing substances, thereby reducing the sulfur content of solid sludge in the homogenized stirring disperser to below 1% (the national standard stipulates that a sulfur content below 1% meets the emission standards).

[0043] S2. Solid sludge moisture content reduction treatment: The pretreated solid sludge is discharged from the homogenizing mixer and disperser onto the conveyor belt and spread out. The conveyor belt slowly passes through the vacuum dryer under continuous vacuum to dry the solid sludge, leaching the moisture from the solid sludge surface.

[0044] More specifically, the homogenizing and dispersing device is only opened to release the solid sludge onto the conveyor belt after the sulfur content of the solid sludge inside the device has decreased to below 1%.

[0045] In addition, the homogenizing mixer and vacuum dryer are connected to an external buffer tank, which is used to recover the sulfur-containing mixture gaseous water under vacuum negative pressure. We recover the gaseous water that was drawn away from S1 and S2 due to vacuum negative pressure. The gaseous water contains hydrogen sulfide and cannot be directly discharged, so the hydrogen sulfide needs to be decomposed. Photocatalytic and electrocatalytic methods can be used to treat it.

[0046] S3. Dry sludge turning and ventilation treatment: The conveyor belt runs continuously and carries the vacuum-dried dry sludge through the air cooler. The conveyor belt turning and the air cooler work alternately to quickly evaporate the moisture on the surface of the dry sludge.

[0047] S4. Preparation of solid fuel from dry sludge: Dry sludge with a moisture content reduced to 20% to 25% is transported to a pelletizing machine, where auxiliary materials are added to increase the calorific value. The pelletizing machine then forms the dry sludge into honeycomb-shaped solid fuel.

[0048] S4. Solid fuel baling: Solid fuel is transported to the baling machine, where it is baled and stored.

[0049] It should be noted that after the solid sludge enters the homogenizing and dispersing unit, the unit stirs and desulfurizes the solid sludge under vacuum and low pressure. Ideally, the vacuum level in both the homogenizing and dispersing unit and the vacuum dryer should be maintained at 1×10⁻⁶. 3 Pa~3×10 4 To ensure the stability of the vacuum level, we activate the data detector to monitor the vacuum level while the homogenizing mixer and vacuum dryer are working. This is used to control the working frequency of the vacuum station. Specifically, we use sensors to detect the vacuum pressure at any time. When the pressure is lower than the set value, we control the vacuum station to increase the compression power.

[0050] The above vacuum drying and desulfurization processes can transform solid sludge (dyeing and printing sludge or biological sludge) with a moisture content below 80% into dry sludge with a moisture content of 20%–25%, and remove sulfur from the solid sludge. The solid sludge was submitted for testing as three types of raw materials: black sludge, yellow sludge, and No. 2 sludge, all of which are dyeing and printing sludge. After centralized processing, the solid sludge was converted into dry sludge, which was then processed into biomass pellets before being submitted for testing. The specific sulfur content data of untreated solid sludge and treated biomass pellets are compared in the table below:

[0051]

[0052] The following table compares the specific water content data of untreated solid sludge and treated biomass pellets:

[0053]

[0054] Equipment for reducing the moisture content of solid sludge, simultaneously desulfurizing and preparing solid fuel, and completing the above-mentioned method for reducing the moisture content of solid sludge, simultaneously desulfurizing and preparing solid fuel, the equipment includes a material conveying channel 1, a homogenizing and dispersing device 2, a vacuum dryer 3, a vacuum station 8, a cool air blower 4, a conveyor belt 5, and a pellet forming machine 6. The material conveying channel 1 is a closed channel structure used to convey solid sludge into the homogenizing and dispersing device to avoid dust. The homogenizing and dispersing device 2 has one or more sets, and is equipped with a stirring and cutting blade set and a dispersing and averaging set. It stirs and cuts at the same time, breaking up the uneven blocky solid sludge and cutting it into fine and uniform particles. The material in the material conveying channel is drawn into the homogenizing and dispersing device 2 under vacuum negative pressure and is cut and stirred under vacuum negative pressure. In addition, a material release valve is provided at the lower end of the homogenizing and dispersing device. The upper end of the homogenizing and dispersing device is closed, and a pipeline is pre-installed to connect to the material conveying channel, so that the solid sludge falls into the container. This closed-loop mixing and cutting avoids the generation of dust. The vacuum dryer 3 is installed on the downstream side of the homogenizing and dispersing device to dry the solid sludge coming out of the homogenizing and dispersing device. The vacuum station is connected to the vacuum negative pressure pipeline and is connected to the homogenizing and dispersing device and the vacuum dryer. The air cooler 4 is installed on the downstream side of the vacuum station to dry the moisture on the surface of the solid sludge. The conveyor belt 5 is divided into multiple sections and is connected to the homogenizing and dispersing device 2, the vacuum dryer 3 and the air cooler 4 to form a solid sludge transfer line. There is one or more pellet forming machines 6, which are installed on the downstream side of the last air cooler.

[0055] The vacuum station simultaneously compresses the air in the homogenizing mixer 2 and the vacuum dryer 3 to maintain a preset vacuum environment. Although the vacuum dryer is not completely sealed and has solid sludge inlet and outlet, as long as the outflow is greater than the inflow, the preset vacuum level can be maintained in a relatively sealed environment. The vacuum station 8 is existing technology and can be directly connected to the homogenizing mixer and the vacuum dryer via a pipeline.

[0056] The desulfurization time can be preset according to the size of the homogenizing and dispersing device 2. The preset capacity of each container of the homogenizing and dispersing device is 1 ton of solid sludge. After the solid sludge is crushed into particles and the desulfurizing agent is added, the granular sludge is released onto the conveyor belt below every 30 minutes of stirring. In this embodiment, the homogenizing and dispersing device is a tilting tank structure with a tilting support. After the solid sludge is stirred, dispersed and fully desulfurized, it is removed from the material conveying channel and the upper sealing cover is opened. The tank tilts at about 60°, so that the solid sludge inside is slowly poured onto the conveyor belt below. Note that the conveyor belt catches the solid sludge during operation, so that a thin layer is spread on the conveyor belt. The conveyor belt slowly carries the solid sludge through the bottom of the vacuum dryer, and under its action, the water inside the small solid sludge particles leach out of the sludge surface.

[0057] The conveyor belts between the vacuum dryer 3 and the cooler 4, and between the coolers 4 and the coolers 4 ( Figure 1 The conveyor belts at points A and B are set up in sections according to upper and lower layers (e.g., Figure 2 As shown in the diagram, the upper and lower conveyor belts have different transport directions, with the lower conveyor belt catching the solid sludge from the upper conveyor belt. That is, the multi-layer conveyor belts are installed in a stacked manner, with the lower conveyor belt catching the sludge from the upper conveyor belt and then transporting it in the opposite direction. This alternation continuously achieves the purpose of turning over the sludge. The turned sludge is then evenly spread on the conveyor belt, which then passes through a cold air blower. The cold air blower removes moisture from the surface of the sludge. This step, combined with vacuum drying technology, removes moisture from both the inside and outside of the solid sludge, achieving the purpose of granulation.

[0058] Conveyor belts can be arranged as follows Figure 1 The assembly line structure shown is suitable for large-scale factory assembly, and can also be assembled as follows: Figure 2 The integrated upper and lower layer structure, with conveyor belts transporting sludge in opposite directions, allows the sludge to be turned over during transport. This continuous turning quickly reduces the moisture content, making it suitable for small-scale applications. The conveyor belts are breathable, and a vacuum dryer continuously applies vacuum above to control and remove moisture from the solid sludge, thus reducing its moisture content.

[0059] It also includes a baler 7, which is installed one-to-one at the discharge end of multiple pellet forming machines. The baler and pellet forming machine can be existing equipment with mature technology.

[0060] It also includes a buffer tank 9, which is installed on the vacuum negative pressure port of the homogenizing mixer and vacuum dryer, and the buffer tank is equipped with a decomposition device for decomposing hydrogen sulfide. The sulfide substances in biological solid sludge or dyeing solid sludge mainly include hydrogen sulfide (H2S) and sulfide ions (S2S). 2 -) Acid-soluble metal sulfides and unionized organic and inorganic sulfides, after reacting with the desulfurizing agent in step S1, are generally drawn away by the vacuum negative pressure. Hydrogen sulfide is a toxic gas with a foul odor and easily escapes from water into the air. Therefore, we designed a device to decompose hydrogen sulfide in the buffer tank. It can first turn gaseous water into liquid water, and then use electrochemical decomposition to decompose hydrogen sulfide into sulfur and hydrogen gas.

[0061] The solid sludge mentioned in this embodiment can be dyeing and printing sludge or biological sludge (solid sludge produced from domestic sewage and aquaculture wastewater). The sludge contains bacteria, organic matter, inorganic matter, fungi, etc., and can be used not only as fuel but also as fertilizer. Sludge produced from dyeing and printing materials can only be used as fuel, while biological sludge (domestic sludge) can be used as organic fertilizer or fuel.

[0062] The process in this embodiment is applicable to two types of solid sludge. In the final step of making solid fuel, in order to achieve a combustion point of 3000 kcal, we can add combustible materials such as sawdust, gluten, and resin to the dried sludge after dehydration and air drying, thereby completing the recycling of biological sludge and dyeing sludge.

[0063] After adding combustible materials to increase the combustible calorie content of biomass pellets, we compared the specific calorie data of untreated solid sludge and treated biomass pellets in the following table:

[0064]

[0065] We conducted two experiments: one with no added fuel calories and one with added fuel calories. Therefore, the biomass pellets submitted for testing had two types. The test results for the biomass pellets without added fuel calories are shown in the table below:

[0066]

[0067]

[0068] The test results of biomass pellets with added fuel calories are shown in the table below:

[0069]

[0070] The above test data proves that this technology and equipment can not only reduce the moisture content of solid sludge but also treat the sulfur in the sludge, enabling the solid fuel produced from its combustion to meet environmental protection requirements. In fact, the sulfur emissions of 0.01-0.02% are even better than the national standard, demonstrating the excellent applicability of this technology. It makes a significant contribution to the treatment of dyeing and printing waste and biological waste. Currently, it has been implemented in several waste treatment plants. The specific treatment equipment consists of 6 to 8 homogenizing and dispersing units operating side-by-side, with a conveyor belt of approximately 250 meters. It can process about 200 tons of solid sludge per day, and the operation is running smoothly. After processing and preparing solid fuel, the waste treatment plant's waste disposal costs are reduced. Previously, the plant paid the combustion station for waste; now, the plant sells solid fuel to the combustion station, directly turning costs into profits.

[0071] The above provides a detailed description of a method and apparatus for reducing the moisture content of solid sludge, simultaneously desulfurizing it, and preparing solid fuel, provided by the present invention. The specific embodiments described are merely for the purpose of helping to understand the method and its core ideas. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles. For example, the ratio of desulfurizing agent to solid sludge may be adjusted, and the solid sludge may be the dry solid sludge described in the background art. These improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for reducing the moisture content of solid sludge, simultaneously desulfurizing it, and preparing solid fuel, characterized in that, Includes the following steps: S1. Solid sludge pretreatment: Solid sludge with a moisture content of less than 80% is conveyed to a homogenizing and dispersing device through a material conveying channel. The homogenizing and dispersing device crushes the solid sludge into uniformly sized particles. Desulfurizing agent is added to the solid sludge according to a predetermined ratio through an automatic dosing device. The solid sludge is then crushed and stirred into honeycomb granules. S2. Solid sludge moisture content reduction treatment: The pretreated solid sludge is discharged from the homogenizing mixer and disperser onto the conveyor belt and spread out. The conveyor belt slowly passes through the vacuum dryer under continuous vacuum to dry the solid sludge, leaching the moisture from the solid sludge surface. S3. Dry sludge turning and ventilation treatment: The conveyor belt runs continuously and carries the vacuum-dried dry sludge through the cold air fan. The conveyor belt turning and the cold air fan work alternately to quickly evaporate the moisture on the surface of the dry sludge. S4. Preparation of solid fuel from dry sludge: Dry sludge with a moisture content reduced to 20% to 25% is transported to a pelletizing machine, which then forms the dry sludge into cylindrical solid fuel. S5. Solid fuel baling: Solid fuel is transported to the baling machine, where it is baled and stored.

2. The method for reducing the moisture content of solid sludge, simultaneously desulfurizing and preparing solid fuel according to claim 1, is characterized in that, The mixing ratio of solid sludge and desulfurizing agent in the homogenizing mixer is 3% to 7%.

3. The method for reducing the moisture content of solid sludge, simultaneously desulfurizing and preparing solid fuel according to claim 1, is characterized in that, After solid sludge enters the homogenizing and dispersing unit, the homogenizing and dispersing unit stirs and desulfurizes the solid sludge under vacuum and low pressure.

4. The method for reducing the moisture content of solid sludge, simultaneously desulfurizing and preparing solid fuel according to claim 1 or 3, is characterized in that, When the homogenizing mixer and vacuum dryer are working, the data detector is activated to detect the vacuum level, which is used to control the working frequency of the vacuum station.

5. The method for reducing the moisture content of solid sludge, simultaneously desulfurizing and preparing solid fuel according to claim 3, is characterized in that, After the sulfur content of the solid sludge in the homogenizing mixer is reduced to below 1%, it is transported to the vacuum dryer.

6. The method for reducing the moisture content of solid sludge, simultaneously desulfurizing and preparing solid fuel according to claim 5, is characterized in that, The homogenizing mixer and vacuum dryer are connected to an external buffer tank, which is used to recover the sulfur-containing mixture gaseous water under vacuum negative pressure.

7. The method for reducing the moisture content of solid sludge, simultaneously desulfurizing and preparing solid fuel according to claim 1, is characterized in that, The solid sludge is either printing and dyeing sludge or biological sludge.

8. Equipment for reducing the moisture content of solid sludge, simultaneously desulfurizing it, and preparing solid fuel, thereby completing the method for reducing the moisture content of solid sludge, simultaneously desulfurizing it, and preparing solid fuel as described in any one of claims 5-7, characterized in that... include: Material conveying channel, a closed channel structure, used to convey solid sludge into the homogenizing and dispersing device; The homogenizing and dispersing unit is a tilting tank structure, with one or more units, and includes an internal stirring and cutting blade assembly and a dispersion and averaging assembly. A vacuum dryer is installed downstream of the homogenizing and dispersing unit to dry the solid sludge exiting from it. A vacuum station is connected to an external vacuum negative pressure pipeline and is linked to both the homogenizing and dispersing unit and the vacuum dryer. A cool air blower, installed downstream of the vacuum station, is used to dry the surface moisture of the solid sludge. The conveyor belt is divided into multiple sections, which are connected to the homogenizing mixer, vacuum dryer and air cooler to form a solid sludge transfer line. There is one or more pellet forming machines installed downstream of the last air cooler.

9. The equipment for reducing the moisture content of solid sludge, simultaneously desulfurizing and preparing solid fuel according to claim 8, is characterized in that: The conveyor belts between the vacuum dryer and the air cooler, and between the air coolers, are arranged in upper and lower sections, with the upper and lower conveyor belts having different transmission directions. The lower conveyor belt catches the solid sludge on the upper conveyor belt.

10. The equipment for reducing the moisture content of solid sludge, simultaneously desulfurizing and preparing solid fuel according to claim 8, characterized in that: It also includes a baling machine and a buffer tank. The baling machine is installed at the discharge end of multiple pellet forming machines, and the buffer tank is installed at the vacuum negative pressure port of the homogenizing mixer and vacuum dryer. The buffer tank is equipped with a decomposition device for decomposing hydrogen sulfide.

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