A sludge drying apparatus

Abstract

This utility model discloses a sludge drying device, belonging to the field of sludge drying technology. It includes a shell, a conveyor belt, an evaporator-condenser assembly, a circulating fan, and a liquefaction heater. A drying chamber is formed in the middle area of ​​one side of the shell. Air ducts connect the upper and lower parts of the drying chamber. A conveyor belt is fixedly installed inside the drying chamber. The evaporator-condenser assembly and the circulating fan are sequentially fixedly installed on one side of the drying chamber. The air duct connected to the air outlet of the drying chamber leads to the evaporator-condenser assembly. The circulating fan is connected below the evaporator-condenser assembly. The output end of the circulating fan is connected to the liquefaction heater. The output end of the liquefaction heater leads to the air duct connected to the air inlet of the drying chamber, forming a closed hot air circulation loop for the drying chamber. Only a small amount of energy is needed to maintain the heat pump operation and compensate for heat loss. All volatile organic waste gas and water vapor generated during sludge drying are condensed and collected within the system to prevent secondary pollution and odor diffusion.

Description

Technical Field

[0001] This utility model belongs to the field of sludge drying technology, and more specifically, relates to a sludge drying device. Background Technology

[0002] Sludge is an inevitable byproduct of wastewater treatment. It is complex in composition, high in water content, and large in volume, making its treatment and disposal difficult and costly. Traditional sludge drying methods typically employ direct heating, such as using coal-fired or gas-fired boilers to provide hot air. This method suffers from high energy consumption, high operating costs, and the potential for generating harmful exhaust gases that cause secondary pollution. Heat pump technology, as a highly efficient and energy-saving technology, has been applied to sludge drying. However, while some existing heat pump drying equipment reduces energy consumption, it suffers from uneven hot air distribution leading to unstable drying efficiency and low heat recovery efficiency. Wet sludge easily adheres to conveyor belts or rollers, causing blockages, cleaning difficulties, and even conveying malfunctions. Furthermore, it lacks adequate exhaust gas treatment. Therefore, a sludge drying device that offers high drying efficiency, is less prone to clogging, and reduces exhaust emissions is needed to address the shortcomings of existing technologies. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a sludge drying device that can meet the requirements of high efficiency, non-clogging and no waste gas emission.

[0004] This utility model discloses a sludge drying device, comprising a shell, a conveyor belt, an evaporator-condenser assembly, a circulating fan, and a liquefaction heater. A drying chamber is formed in the middle area of ​​one side of the shell. Air ducts connect the upper and lower parts of the drying chamber. A conveyor belt is fixedly installed inside the drying chamber. The evaporator-condenser assembly, circulating fan, and liquefaction heater are sequentially fixedly installed on one side of the drying chamber. The air duct connected to the air outlet of the drying chamber leads to the evaporator-condenser assembly. The circulating fan is connected below the evaporator-condenser assembly, and its output end is connected to the liquefaction heater. The output end of the liquefaction heater leads to the air duct connected to the air inlet of the drying chamber, forming a closed-loop hot air circulation loop for the drying chamber. Only a small amount of energy is needed to maintain the heat pump operation and compensate for heat loss, avoiding the huge energy consumption of traditional open systems that continuously heat large amounts of fresh air. All volatile organic waste gas and water vapor generated during sludge drying are condensed and collected within the system, preventing them from overflowing into the environment and avoiding secondary pollution and odor diffusion.

[0005] As a further improvement of this utility model, a sludge inlet is provided at the top of the outer shell, and a dry material outlet is provided at the lower end of one side. The starting point and ending point of the conveyor belt are respectively connected to the sludge inlet and the dry material outlet. The drying chamber is located on the side close to the dry material outlet. The closed hot air circulation loop is counter-current. The air inlet of the drying chamber is located at the bottom and the air outlet is located at the top. The hottest drying air generated by the liquefied heater is sent into the drying chamber from the bottom, and the hot and humid air is discharged from the top. This allows the blown hot and dry air to rise naturally according to the hot airflow movement law, reducing the airflow resistance and reducing the energy consumption of the circulating fan.

[0006] As a further improvement of this utility model, the conveyor belt is fixed to the inner wall of the outer shell by the frame. The conveyor belt includes an upper belt and a lower belt that are independent of each other. The upper belt and the lower belt are each supported and driven by large-diameter active rollers and driven rollers at both ends of the frame. A mesh belt is laid on the active rollers and the driven rollers. The mesh belt is a steel wire mesh belt, which increases the contact area between hot air and sludge and allows hot air to penetrate the material layer, so that the heat and mass exchange is more complete.

[0007] As a further improvement of this utility model, a cleaning mechanism is fixedly installed between the mesh belts of the upper and lower belts. The cleaning mechanism includes a scraper and a blower, which are installed sequentially along the conveying direction of the return section of the mesh belt. The scraper maintains a small gap with the bottom surface of the mesh belt, and the blower blows air towards the scraper. When the conveyor belt starts, the blade of the scraper can contact the non-working surface of the mesh belt in the return section of the conveyor belt through the mechanical vibration of the mesh belt and scrape off the sludge, preventing wet sludge particles from clogging the mesh. The blower's blowing port faces the non-working surface of the mesh belt and the gaps of the drive components, reducing the frequency of downtime for cleaning and ensuring the continuous production capacity of the device.

[0008] As a further improvement of this utility model, the scraper includes a blade body, a blade holder, and a pair of adjusting springs. The two ends of the pair of adjusting springs are fixedly connected to the bottom of the frame and the blade holder, respectively. The head of the blade holder is fixedly connected to the blade body. The sharpened side of the blade body contacts the mesh belt at the return end of the conveyor belt. When the scraper is in static standby mode, the preload of the adjusting spring causes the blade body to slightly contact the mesh belt. As the mesh belt moves and vibrates, the sludge that adheres to it moves accordingly. The elastic cleaning of the blade body allows the normal thin layer of sludge to be scraped off directly. If a large sticky block is encountered, the blade body is lifted up by the action of the adjusting spring. After the block passes, the deformation of the adjusting spring causes the blade body to return to its original position, maintaining effective cleaning while protecting the mesh belt.

[0009] As a further improvement of this utility model, the blower includes a blower, a main air supply pipe, and a blower pipe. The blower is installed on one side of the housing and serves as the air source for the blower in the air source station. The outlet of the blower is connected to the main air supply pipe, which extends along the frame to the space between the upper and lower mesh belts. The end of the main air supply pipe is connected to the blower pipe. The blower is installed in an open area, and maintenance and replacement do not require disassembling the conveyor belt. It can bypass various mechanical structures and accurately deliver the airflow to the target point.

[0010] As a further improvement of this utility model, it also includes a water collection tray and an external cooling fan. The evaporator-condenser assembly includes a condenser and an evaporator. The top of the condenser is connected to the air duct, and a water collection tray is fixedly installed at the bottom of the condenser. The evaporator is fixedly installed below the condenser and connected to the condenser through a copper pipe. One side of the evaporator is connected to the external cooling fan, which realizes efficient dehumidification and prevents harmful water vapor from being discharged and diffused.

[0011] As a further improvement of this utility model, the liquefaction heater is installed on one side of the air outlet of the circulating fan and is connected to the air duct connected to the air inlet below the drying chamber. The liquefaction heater is selected as a finned heat exchanger, and the lower end of the finned heat exchanger can be connected to the outside of the device to complete the water inlet and outlet.

[0012] As a further improvement of this utility model, a pair of pressure rollers are rotatably installed inside the sludge inlet to press the sludge into blocks and feed them into the conveyor belt, preventing loose sludge from falling directly into the bottom of the device.

[0013] As a further improvement of this utility model, an air distribution plate is provided at the air inlet of the drying chamber. The air distribution plate has several through holes, and the opening ratio of the through holes in the central area is smaller than that in the edge area. Since the output port of the circulating fan cannot completely cover the air inlet, the air force in the central area of ​​the air inlet is stronger than that in the edge area. Increasing the opening ratio in the edge area can evenly distribute the hot air output by the circulating fan, so that the heat energy can be fully utilized, avoiding energy waste caused by airflow short circuits or dead corners, and improving the thermal efficiency and drying efficiency of the system.

[0014] Compared with the prior art, the advantages of this utility model are as follows: the drying process uses a closed hot air circulation loop, which only requires a small amount of energy to maintain the operation of the heat pump and compensate for heat loss, thus avoiding the huge energy consumption of traditional open systems that continuously heat a large amount of fresh air; the sludge is removed by the scraper and blower of the cleaning mechanism, preventing wet sludge particles from clogging the mesh belt; all the organic waste gas and water vapor volatilized during the sludge drying process are condensed and collected inside the system and will not overflow into the environment, preventing secondary pollution and odor diffusion; The mesh conveyor belt increases the contact area between hot air and sludge, and allows hot air to penetrate the material layer, making heat and mass exchange more complete. It also prevents sludge dust from entering precision transmission components, making cleaning and maintenance easier. The counter-flow blowing reduces airflow resistance and lowers the energy consumption of the circulating fan. It is equipped with an air distribution plate to make full use of heat energy and avoid energy waste caused by airflow short circuits or dead zones, thereby improving the system's thermal efficiency and drying efficiency. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the front view of the present invention after removing the outer shell; Figure 2 This is a schematic diagram of the structure with an outer shell of this utility model; Figure 3 This is a schematic diagram of the drying chamber and its connection relationship of the present invention; Figure 4 This is a left-side view of the drying chamber of this utility model; Figure 5 This is a schematic diagram of the conveyor belt structure of this utility model; Figure 6 This is a schematic diagram of the evaporator-condenser and its connection relationship according to the present invention; Figure 7 This is a left-side view of the evaporator-condenser assembly of this utility model; Figure 8 This is a schematic diagram of the water receiving tray structure of this utility model; Figure 9 For the present utility model Figure 1 Enlarged view of region A in the middle; Figure 10 This is a schematic diagram of the scraper structure of this utility model; Figure 11 This is a schematic diagram of the purger structure and pipeline distribution of this utility model; Figure 12 This is a schematic diagram of the wind distribution plate structure of this utility model.

[0016] Explanation of the labels in the diagram: 1. Outer shell; 11. Sludge inlet; 12. Drying chamber; 121. Air outlet; 122. Dry material outlet; 13. Air duct; 14. Pressure roller; 15. Conveyor belt; 2. Upper belt; 21. Lower belt; 22. Driven roller; 23. Driven roller; 24. Mesh belt; 25. Evaporator-condenser assembly; 3. Condenser; 31. Evaporator; 32. Circulating fan; 4. Outlet; 41. Liquefaction heater; 5. Water tray; 6. External cooling fan; 7. Cleaning mechanism; 8. Scraper; 81. Scraper body; 811. Scraper holder; 812. Adjusting spring; 813. Blower; 821. Main air supply duct; 822. Blowing pipe; 823. Air distribution plate; 9. Through hole; 91. Detailed Implementation

[0017] Specific Implementation Example 1: Please refer to Figures 1-12 This utility model relates to a sludge drying device, comprising a sealed outer shell 1. The top of the outer shell 1 has a sludge inlet 11, and the lower side has a dry material outlet 13. The internal space of the outer shell 1 near the dry material outlet 13 forms a drying chamber 12. A conveyor belt 2 is fixedly installed in the drying chamber 12 via a frame for conveying and agitating the sludge. An evaporator-condenser assembly 3 and a circulating fan 4 are installed sequentially from top to bottom on one side of the drying chamber 12. The outlet of the circulating fan 4 faces the side where the drying chamber 12 is located. The drying chamber 12 has an air outlet 121 at the top and an air inlet 1 at the bottom. 22. An air duct 14 is formed in the space between the upper and lower parts of the drying chamber 12 and the outer shell 1. The air outlet 121 of the drying chamber 12 is connected to the inlet at the upper end of the evaporator-condenser group 3 through the upper air duct 14, and the air inlet 122 is connected to the outlet of the circulating fan 4 through the lower air duct. The outlet at the lower end of the evaporator-condenser group 3 is connected to the circulating fan 4. A liquefaction heater 5 is also installed at the outlet of the circulating fan 4. The air blown out by the circulating fan 4 is heated by the liquefaction heater 5 and flows through the lower air duct 14 to the air inlet 122 at the bottom of the drying chamber 12, thereby forming a closed hot air circulation loop.

[0018] In a further embodiment, such as Figure 1 As shown, the conveyor belt 2 includes an independent upper belt 21 and a lower belt 22. The upper belt 21 and the lower belt 22 are supported and driven by two sets of large-diameter active rollers 23 and driven rollers 24 rotatably connected to both ends of the frame. Each set of active rollers 23 and driven rollers 24 is covered with a mesh belt 25. That is, one active roller 23, one driven roller 24 and one mesh belt 25 constitute a conveyor belt. The conveyor belt near the sludge inlet is designated as the upper belt 21, and the conveyor belt near the dry material outlet 13 is designated as the lower belt 22. The mesh belt 25 is a steel wire mesh belt.

[0019] In a further embodiment, such as Figure 3 As shown, a pair of pressure rollers 15 are rotatably installed inside the sludge inlet 11 to press the sludge into blocks and feed it into the conveyor belt 2, preventing loose sludge from falling directly into the bottom of the device.

[0020] In a further embodiment, such as Figure 9As shown, a cleaning mechanism 8 is fixedly installed between the mesh belts 25 of the upper belt 21 and the lower belt 22. The cleaning mechanism 8 includes a scraper 81 and a blower 82. The scraper 81 is installed on the frame on the side close to the drive roller 23, and the blower 82 is installed on the frame on the side away from the drive roller 23. The scraper 81 maintains a small gap with the bottom surface of the mesh belt 25, and the blower 82 blows air towards the scraper 81. When the conveyor belt 2 starts, the scraper 81 can contact the non-working surface of the mesh belt 25 of the return section of the conveyor belt 2 through the mechanical vibration of the mesh belt 25 and scrape off the sludge, preventing wet sludge particles from clogging the mesh. The blower 82 blows towards the non-working surface of the mesh belt 25 and the drive roller 23, reducing the frequency of shutdown for cleaning and ensuring the continuous production capacity of the device.

[0021] In a further embodiment, such as Figure 10 As shown, the scraper 81 includes a blade body 811, a blade holder 812, and a pair of adjusting springs 813. The two ends of the pair of adjusting springs 813 are fixedly connected to the frame and the bottom of the blade holder 812, respectively. The head of the blade holder 812 is fixedly connected to the blade body 811. The sharpened side of the blade body 811 contacts the mesh belt 25 at the return end of the conveyor belt. When the scraper 81 is in static standby mode, the preload of the adjusting springs 813 causes the blade body 811 to slightly contact the mesh belt 25. As the mesh belt 25 moves and vibrates, the sludge that adheres to it moves accordingly. The elastic cleaning of the blade body 811 allows the normal thin layer of sludge to be scraped off directly. If a large sticky block is encountered, the blade body 811 is lifted up by the action of the adjusting springs 813. After the block passes, the deformation of the adjusting springs 813 causes the blade body 811 to return to its original position, maintaining effective cleaning while protecting the mesh belt 25.

[0022] In a further embodiment, such as Figure 11 As shown, the purger 82 includes a blower 821, a main air supply duct 822, and a purge pipe 823. The blower 821 is installed on one side of the housing 1 and serves as the air source for the purger 82. The blower's outlet is connected to the main air supply duct 822. The main air supply duct 822 extends along the frame to the area between the upper belt 21 and the mesh belt 25 and the lower belt 22 and the mesh belt 25, respectively. The end of the main air supply duct 822 is connected to the purge pipe 823. The blower is installed in an open area, and maintenance and replacement do not require disassembling the conveyor belt. It can bypass various mechanical structures and accurately deliver the airflow to the target point.

[0023] In a further embodiment, such as Figures 6-7 As shown, it also includes a water collection tray 6 and an external cooling fan 7. The evaporator-condenser assembly 3 includes a condenser 31 and an evaporator 32. The top of the condenser 31 is connected to the air duct 14. A water collection tray 6 is fixedly installed at the bottom of the condenser 31. The water collection tray 6 collects the condensed water generated by the condenser 31 and connects to the outside through a pipe. The evaporator 32 is fixedly installed below the condenser 31 and connected to the condenser 31 through a copper pipe. One side of the evaporator 32 is connected to the external cooling fan 7.

[0024] In a further embodiment, such as Figure 1 and Figure 6 As shown, the liquefaction heater 5 is installed on one side of the air outlet 121 of the circulating fan 4 and is connected to the air duct 14 connected to the air inlet below the drying chamber 12. The liquefaction heater 5 is selected as a finned heat exchanger. The lower end of the finned heat exchanger can be connected to the outside of the device to complete the water inlet and outlet. The heat circulation of the whole device can be achieved by providing a small amount of heat through external hot water.

[0025] In a further embodiment, such as Figure 1 and Figure 8 As shown, an air distribution plate 9 is provided at the air inlet 122 of the drying chamber 12. The air distribution plate 9 has several through holes 91. The opening ratio of the through holes 91 in the central area is smaller than that in the edge area. Since the output port 41 of the circulating fan 4 cannot completely cover the air inlet 122, the air force in the central area of ​​the air inlet 122 is stronger than that in the edge area, which easily leads to insufficient airflow distribution. By increasing the opening ratio of the edge area of ​​the air distribution plate 9, the hot air output by the circulating fan 4 can be evenly distributed, so that the heat energy can be fully utilized, avoiding energy waste caused by airflow short circuit or dead corner, and improving the thermal efficiency and drying efficiency of the system.

[0026] Wet sludge is fed into the sludge inlet 11 at the top, falls onto the conveyor belt 2, and is slowly conveyed through the high-temperature drying chamber 12. Inside the drying chamber 12, hot dry air generated by the liquefaction heater 5 is blown upward from the bottom of the chamber, forming a countercurrent contact with the sludge conveyed from top to bottom, fully exchanging heat and mass, evaporating the moisture in the sludge. The humidified hot air is extracted from the top of the drying chamber 12 and enters the evaporator condenser group 3 for cooling and dehumidification. The water vapor in the air is condensed into liquid water and falls into the water collection pan 6 before being discharged. The cooled dry air is then sent back to the liquefaction heater 5 by the circulating fan 4 to be reheated to the required temperature, and finally sent back to the bottom of the drying chamber 12. The reheated hot dry air is reintroduced into the drying chamber 12 through a closed hot air circulation loop. This process continues until the sludge is dried into dry material and discharged from the dry material outlet 13 at the bottom of the device.

Claims

1. A sludge drying device, characterized in that: The device includes an outer shell (1), a conveyor belt (2), an evaporator-condenser assembly (3), a circulating fan (4), and a liquefaction heater (5). The middle area of ​​one side of the outer shell (1) forms a drying chamber (12). The upper and lower parts of the drying chamber (12) are connected by air ducts (14). The conveyor belt (2) is fixedly installed inside the drying chamber (12). The evaporator-condenser assembly (3) and the circulating fan (4) are fixedly installed on one side of the drying chamber (12). The air duct (14) connected to the air outlet of the drying chamber (12) leads to the evaporator-condenser assembly (3). The circulating fan (4) is connected below the evaporator-condenser assembly (3). The output end of the circulating fan (4) is connected to the liquefaction heater (5). The output end of the liquefaction heater (5) leads to the air duct (14) connected to the air inlet of the drying chamber (12), so as to form a closed hot air circulation loop for the drying chamber (12).

2. A sludge dewatering apparatus as claimed in claim 1, characterised in that: The top of the outer shell (1) is provided with a sludge inlet (11) and the bottom of one side is provided with a dry material outlet (13). The starting point and the ending point of the conveyor belt (2) are respectively connected to the sludge inlet (11) and the dry material outlet (13). The drying chamber (12) is located on the side close to the dry material outlet (13). The closed hot air circulation loop is counter-current. The drying chamber (12) includes an air outlet (121) and an air inlet (122). The air inlet (122) is located at the bottom and the air outlet (121) is located at the top. The hottest drying air generated by the liquefied heater (5) is sent into the drying chamber (12) from the bottom and the hot and humid air is discharged from the top.

3. The sludge drying device according to claim 1, characterized in that: The conveyor belt (2) is fixed to the inner wall of the outer shell (1) by the frame. The conveyor belt (2) includes an upper belt (21) and a lower belt (22) that are independent of each other. The upper belt (21) and the lower belt (22) are supported and driven by two sets of active rollers (23) and driven rollers (24) that are rotatably connected to both ends of the frame. Each set of active rollers (23) and driven rollers (24) is covered with a mesh belt (25), which is a steel wire mesh belt.

4. A sludge dewatering apparatus as claimed in claim 3, wherein: A cleaning mechanism (8) is fixedly installed between the mesh belts (25) of the upper belt (21) and the lower belt (22). The cleaning mechanism (8) includes a scraper (81) and a blower (82). The scraper (81) and the blower (82) are installed sequentially along the return section of the mesh belt (25). The scraper (81) maintains a small gap with the bottom surface of the mesh belt (25). When the conveyor belt (2) is conveyed, the blade of the scraper (81) can contact the non-working surface of the return section of the conveyor belt (2). The blower (82) blows air towards the scraper (81).

5. A sludge dewatering device as claimed in claim 1, characterized in that: It also includes a water tray (6) and an external cooling fan (7). The evaporator-condenser assembly (3) includes a condenser (31) and an evaporator (32). The top of the condenser (31) is connected to the air duct (14). A water tray (6) is fixedly installed at the bottom of the condenser (31). The evaporator (32) is fixedly installed below the condenser (31) and connected to the condenser (31) through a copper pipe. The external cooling fan (7) is connected to one side of the evaporator (32).

6. A sludge dewatering device as claimed in claim 1, characterized in that: The liquefaction heater (5) is installed on one side of the air outlet of the circulating fan (4) and is connected to the air duct (14) connected to the air inlet below the drying chamber (12). The liquefaction heater (5) is selected as a finned heat exchanger. The lower end of the finned heat exchanger can be connected to the outside of the device to complete the water inlet and outlet.

7. A sludge dewatering device as claimed in claim 1, characterized in that: A uniform air distribution plate (9) is provided at the air inlet of the drying chamber (12). The uniform air distribution plate (9) has several through holes (91), and the opening ratio of the through holes (91) in the central area is smaller than that of the through holes (91) in the edge area.

8. A sludge dewatering device as claimed in claim 2, characterized in that: A pair of pressure rollers (15) are rotatably installed inside the sludge inlet (11).

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