Sludge low-temperature drying equipment

Abstract

The utility model relates to low-temperature sludge drying equipment. The device comprises a drying conveying belt, a slurry feeding assembly and a low-temperature drying assembly. The slurry feeding assembly comprises a slurry barrel, a feeding screw, a motor, a discharging opening and a slurry spreading flat pipe. The low-temperature drying assembly is composed of an air blower, a heat exchanger, a drying box, a condenser and a closed-loop air pipe, the air blower, the heat exchanger, the drying box and the condenser are sequentially connected to the closed-loop air pipe in series, and the drying conveying belt penetrates through the drying box. Sludge is flatly spread on the drying conveying belt through the slurry feeding assembly, so that the ratio of the surface area to the volume of the sludge is sharply increased, and the heat transfer efficiency and the evaporation rate can be effectively improved; the low-temperature drying assembly adopts low-temperature gas to heat and dry sludge, energy consumption can be reduced, meanwhile, circulating gas is adopted, the heat utilization rate can be obviously increased, and energy consumption is reduced.

Description

Technical Field

[0001] This utility model relates to a sludge drying device, and more particularly to a low-temperature sludge drying device. Background Technology

[0002] Currently, the discharge of urban industrial wastewater and domestic sewage is increasing daily, leading to a surge in sewage treatment volume and a dramatic increase in sludge production from sewage treatment plants. While using physicochemical and biological methods to treat sewage, a large amount of excess sludge is generated. Sludge with high organic content must be treated and disposed of promptly to prevent secondary pollution. The main methods for sludge disposal are landfill, agricultural use, building material utilization, and incineration. The heavy metal content in sludge from industrial wastewater often exceeds standards, making direct agricultural use impossible. Landfill and building material utilization are the most common solutions. Landfilling requires transporting the sludge to specialized landfills, which are typically long distances. Conventional mechanical dewatering processes still result in high moisture content, leading to high transportation costs. Building material utilization also requires the sludge moisture content to be controlled below 55%. Therefore, after mechanical dewatering, current sludge treatments often require drying to further reduce its moisture content. Common drying methods include natural air drying and heated air drying. Natural air drying has low efficiency and requires a large amount of space, while heated air drying has relatively high drying efficiency. However, existing heated air drying processes have problems such as low heat utilization, high energy consumption, and high cost. Summary of the Invention

[0003] This invention provides a low-temperature sludge drying device, which solves the problems of low heat utilization and high energy consumption in the sludge drying process in the prior art.

[0004] The above-mentioned technical problems of this utility model are mainly solved by the following technical solution: a low-temperature sludge drying device, including a drying conveyor belt, a sludge coating component, and a low-temperature drying component; the belt body of the drying conveyor belt is a stainless steel mesh structure, and its mesh count is generally between 20 and 50 meshes, and the main body of the drying conveyor belt is horizontally distributed; the sludge coating component includes a sludge tank, a feeding screw located at the bottom of the sludge tank, a motor driving the feeding screw to rotate and located outside the sludge tank, and a component disposed in the sludge tank. The bottom has a discharge port and a mud-spreading flat tube connected to the discharge port. The output end of the feeding screw extends into the discharge port. The inner cavity of the mud-spreading flat tube gradually flattens in height and gradually lengthens in width. The discharge end of the mud-spreading flat tube is located above the front end of the drying conveyor belt. The low-temperature drying assembly consists of a blower, a heat exchanger, a drying chamber, a condenser, and a closed-loop air duct. The blower, the heat exchanger, the drying chamber, and the condenser are connected in series on the closed-loop air duct. The drying conveyor belt passes through the drying chamber.

[0005] The object of this invention is sludge that has undergone preliminary mechanical dewatering. The water content of this sludge is generally between 70% and 85%, and its state is a viscous semi-fluid slurry. The sludge is fed into the sludge tank via a conveying device. The motor drives the feeding screw to rotate at a constant speed, causing the sludge to flow towards the discharge port. After flowing into the sludge spreading tube, the sludge is extruded in thin sheets and spread evenly on the upper surface of the drying conveyor belt. The moving speed of the drying conveyor belt is the same as or slightly higher than the extrusion speed of the sludge sheets in the spreading tube. This avoids the phenomenon of localized accumulation of sludge sheets in a curved shape on the drying conveyor belt. The drying conveyor belt has a stainless steel mesh structure, so both sides of the sludge sheets can have good contact with the air. The sludge sheets move slowly backward with the drying conveyor belt until they enter the drying chamber. Hot air flows in the drying chamber. This hot air can heat the sludge sheets, increase the evaporation rate of the internal moisture, and remove water vapor. Then, this mixed gas passes through the condenser, blower, and heat exchanger in sequence along the closed-loop air duct, and finally enters the drying chamber again to achieve a closed-loop cycle. Most of the water vapor in the mixed gas will be liquefied and removed in the condenser. The cooled gas is reheated to 65 to 80°C through the heat exchanger. The sludge flakes are slowly dried in the drying chamber until their moisture content is below 55%, after which they can be unloaded from the drying conveyor belt. This invention utilizes a sludge feeding assembly to spread the sludge evenly on the drying conveyor belt, drastically increasing the surface area to volume ratio of the sludge. This effectively improves heat transfer efficiency and evaporation rate. The low-temperature drying assembly uses low-temperature gas to heat and dry the sludge, reducing energy consumption. Furthermore, the use of circulating gas significantly improves heat utilization and further reduces energy consumption.

[0006] The mesh size of the stainless steel mesh should be selected based on the moisture content of the sludge. Since the object of this invention is viscous semi-fluid sludge, the mesh size requirement for the stainless steel mesh is relatively low. Therefore, the mesh size is set between 20 and 50 mesh. On the premise of ensuring that the stainless steel mesh can completely hold the sludge, the mesh size of the stainless steel mesh should be reduced as much as possible. This can reduce the production and replacement costs of the drying conveyor belt.

[0007] Furthermore, this utility model also includes a feeding conveyor belt, a feeding scraper, and a mudguard. A mounting frame is fixed to the rear end of the drying conveyor belt, and the feeding scraper is rotatably mounted on the mounting frame. Under its own weight, the feeding scraper flips towards one side of the drying conveyor belt to abut against it. The mudguard is obliquely fixed to the mounting frame and located above the feeding scraper. The front end of the feeding conveyor belt is located below the feeding scraper. The mud flakes at the rear end of the drying conveyor belt are in a relatively dry state, essentially solid. The stainless steel mesh at the rear end of the drying conveyor belt undergoes arc deformation, so the mud flakes on it may remain adhered to the mesh and break, or they may remain straight and separate from the mesh. The feeding scraper removes the mud flakes adhering to the mesh, and the mudguard breaks the mud flakes, allowing them to slide down the feeding scraper onto the feeding conveyor belt and be output with it.

[0008] Furthermore, in a top-down view, the outlet profile of the sludge spreading tube is a convex arc shape. This design ensures that the sludge flows along a similar path regardless of the direction from which it exits the tube, resulting in a more uniform sludge extrusion rate at the outlet and thus better flatness of the sludge sheet.

[0009] Furthermore, the inner cavity of the mud-spreading flat tube is provided with several slotted teeth on the upper and rearward side. The slotted teeth allow continuous slots to be formed on the upper surface of the mud sheet, further increasing the surface area of ​​the mud sheet, which is beneficial to improving heat transfer efficiency and evaporation rate.

[0010] Therefore, this utility model has the following characteristics compared with the prior art: 1. This utility model uses a slurry feeding component to spread the sludge evenly on the drying conveyor belt, which greatly increases the surface area to volume ratio of the sludge, effectively improving heat transfer efficiency and evaporation rate; 2. The low-temperature drying component uses low-temperature gas to heat and dry the sludge, which can reduce energy consumption. At the same time, the use of circulating gas can significantly improve the heat utilization rate and reduce energy consumption. Attached Figure Description

[0011] Appendix Figure 1 This is a schematic diagram of the structure of this utility model;

[0012] Appendix Figure 2 This is a schematic diagram of the mud coating assembly.

[0013] Appendix Figure 3 This is a schematic diagram of the structure of the mud-spreading flat tube;

[0014] Appendix Figure 4 This is a schematic diagram of the material outlet of the mud-spreading flat tube. Detailed Implementation

[0015] The technical solution of this utility model will be further described in detail below through embodiments and in conjunction with the accompanying drawings.

[0016] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0017] Example 1: See Figure 1 and Figure 2 A low-temperature sludge drying device includes a drying conveyor belt 100, a sludge coating component 200, and a low-temperature drying component 300. The drying conveyor belt has a stainless steel mesh structure with a mesh size between 35 and 45, and the main body of the drying conveyor belt is horizontally distributed. The sludge coating component includes a sludge tank 210, a feeding screw 220 located at the bottom of the sludge tank, a motor 230 that drives the feeding screw to rotate and is located outside the sludge tank, a discharge port 240 located at the bottom of the sludge tank, and a sludge spreading flat pipe 240 connected to the discharge port. 50. The mud bucket is covered with a bucket lid 211, and a grouting pipe 212 is installed on the bucket lid. The output end of the feeding screw extends into the discharge port. The inner cavity of the mud spreading flat pipe gradually flattens in height and gradually lengthens in width. The discharge end of the mud spreading flat pipe is located above the front end of the drying conveyor belt. The low-temperature drying assembly consists of a blower 310, a heat exchanger 320, a drying chamber 330, a condenser 340, and a closed-loop air duct 350. The blower, heat exchanger, drying chamber, and condenser are connected in series on the closed-loop air duct. The drying conveyor belt passes through the drying chamber. The heat exchanger is specifically a tubular heat exchanger, and the condenser is specifically a shell-and-tube condenser.

[0018] The processing object of this embodiment is sludge that has undergone preliminary mechanical dewatering. The water content of this sludge is generally between 70% and 85%, and its state is a viscous semi-fluid slurry. The sludge is injected into the sludge tank through the grouting pipe. The motor drives the feeding screw to rotate at a constant speed, causing the sludge to flow towards the discharge port. After flowing into the sludge spreading tube, the sludge is extruded in thin sheets, with the thickness of the sheets controlled at 4 to 6 mm. The sheets are then spread evenly on the upper surface of the drying conveyor belt. The moving speed of the drying conveyor belt is the same as or slightly higher than the extrusion speed of the sludge sheets from the spreading tube. This avoids the phenomenon of bent local accumulation of sludge sheets on the drying conveyor belt. The drying conveyor belt has a stainless steel mesh structure, so both sides of the sludge sheets can have good contact with the air. The sludge sheets move slowly backward with the drying conveyor belt until they enter the drying chamber. Hot air flows inside the drying chamber. This hot air can heat the sludge sheets, increase the evaporation rate of the internal moisture, and remove water vapor. Then, this mixed gas passes through the condenser, blower, and heat exchanger in sequence along the closed-loop air duct, and finally enters the drying chamber again to achieve a closed-loop cycle. Most of the water vapor in the mixed gas will be liquefied and removed in the condenser. The cooled gas is reheated to 65 to 80°C through the heat exchanger. The sludge flakes are slowly dried in the drying chamber until their moisture content is below 55%, after which they can be unloaded from the drying conveyor belt. In this embodiment, a sludge feeding assembly is used to spread the sludge evenly on the drying conveyor belt, which dramatically increases the surface area to volume ratio of the sludge, effectively improving heat transfer efficiency and evaporation rate. The low-temperature drying assembly uses low-temperature gas to heat and dry the sludge, which can reduce energy consumption. At the same time, the use of circulating gas can significantly improve heat utilization and reduce energy consumption.

[0019] The mesh size of the stainless steel mesh should be selected based on the moisture content of the sludge. Since the object to be treated in this embodiment is a viscous semi-fluid sludge, the mesh size requirement for the stainless steel mesh is relatively low. Therefore, the mesh size is set between 35 and 45 mesh. On the premise of ensuring that the stainless steel mesh can completely hold the sludge, the mesh size of the stainless steel mesh should be reduced as much as possible. This can reduce the production and replacement costs of the drying conveyor belt.

[0020] See Figure 1This embodiment also includes a feeding conveyor belt 400, a feeding scraper 410, and a mudguard 420. A mounting frame 430 is fixed to the rear end of the drying conveyor belt, and the feeding scraper is rotatably mounted on the mounting frame. Under its own weight, the feeding scraper flips towards one side of the drying conveyor belt to abut against it. The mudguard is tilted and fixed to the mounting frame and located above the feeding scraper. The front end of the feeding conveyor belt is located below the feeding scraper. The mud flakes at the rear end of the drying conveyor belt are in a relatively dry state, essentially solid. The stainless steel mesh at the rear end of the drying conveyor belt undergoes arc deformation, so the mud flakes on it may remain adhered to the mesh and break, or they may remain straight and separate from the mesh. The feeding scraper removes the mud flakes adhering to the mesh, and the mudguard breaks the mud flakes, allowing them to slide down the feeding scraper onto the feeding conveyor belt and be output with it.

[0021] See Figure 3 From a top-down perspective, the outlet profile of the sludge spreading tube is a convex arc shape. This design ensures that the sludge flows along a similar path regardless of the direction from which it exits the tube, resulting in a more uniform sludge extrusion rate at the outlet and thus better flatness of the sludge sheets.

[0022] See Figure 4 The inner cavity of the mud-spreading flat tube has several slotted teeth 251 on the upper side and rearward region. The slotted teeth allow the upper surface of the mud sheet to form continuous slots, further increasing the surface area of ​​the mud sheet, which is beneficial to improving heat transfer efficiency and evaporation rate.

[0023] See Figure 2 A weighing sensor 260 is installed at the bottom of the mud tank, and a support base 270 is fixed at the bottom of the weighing sensor. The support base is located above the drying conveyor belt and is fixedly set. The weighing sensor can weigh the load on the upper side in real time, so that the control center can track the amount of sludge remaining in the mud tank in real time. When the amount of sludge remaining is insufficient, it can notify the control center to replenish the sludge.

[0024] This invention can be modified in many ways, as will be apparent to those skilled in the art, and such modifications are not considered to depart from the scope of this invention. All such modifications that are obvious to those skilled in the art are included within the scope of these claims.

Claims

1. A low-temperature sludge drying device, characterized in that: The system includes a drying conveyor belt, a slurry coating assembly, and a low-temperature drying assembly. The drying conveyor belt has a stainless steel mesh structure and its main body is horizontally distributed. The slurry coating assembly includes a slurry tank, a feeding screw located at the bottom of the slurry tank, a motor driving the feeding screw and located outside the slurry tank, a discharge port located at the bottom of the slurry tank, and a slurry spreading flat tube connected to the discharge port. The output end of the feeding screw extends into the discharge port. The inner cavity of the slurry spreading flat tube gradually flattens in height and gradually lengthens in width. The discharge end of the slurry spreading flat tube is located above the front end of the drying conveyor belt. The low-temperature drying assembly consists of a blower, a heat exchanger, a drying chamber, a condenser, and a closed-loop air duct. The blower, the heat exchanger, the drying chamber, and the condenser are connected in series on the closed-loop air duct. The drying conveyor belt passes through the drying chamber.

2. The sludge low-temperature drying equipment according to claim 1, characterized in that: It also includes a feeding conveyor belt, a feeding scraper, and a mudguard. A mounting frame is fixed to the rear end of the drying conveyor belt. The feeding scraper is rotatably mounted on the mounting frame. The feeding scraper will flip to one side of the drying conveyor belt to abut against it due to its own weight. The mudguard is inclined and fixed on the mounting frame and located above the feeding scraper. The front end of the feeding conveyor belt is located below the feeding scraper.

3. The sludge low-temperature drying equipment according to claim 1, characterized in that: From a top-down view, the outlet profile of the mud-spreading flat tube is an outwardly convex arc shape.

4. The sludge low-temperature drying equipment according to claim 3, characterized in that: The inner cavity of the mud-spreading flat tube has several slotted teeth on the upper and rearward side.

5. The sludge low-temperature drying equipment according to claim 1, characterized in that: The bottom of the mud tank is equipped with a weighing sensor, and the bottom of the weighing sensor is fixed with a support base. The support base is located above the drying conveyor belt and is fixedly positioned relative to it.

6. The sludge low-temperature drying equipment according to claim 5, characterized in that: The mud bucket is covered with a lid, and the lid is equipped with a grouting pipe.

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