Sludge resource disposal system based on waste heat utilization of rotary tunnel kiln
Patent Information
- Application Number
- CN202522486149.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-24
- Publication Date
- 2026-10-13
- Estimated Expiration
- 2035-11-24
AI Technical Summary
传统的热干化方法需要消耗大量的煤、天然气等一次能源，成本高昂，且存在二次污染风险；填埋则占用土地，并且易造成土壤和地下水污染
[0015]本实用新型技术方案的有益效果在于：本实用新型提供的污泥资源化处置系统，通过将余热采集单元、污泥烘干单元和热风回收单元集成于旋转隧道窑上，并创新性地设计了与窑炉轨道同轴的环状第二输送管及配套下料机构，匹配动态运行的旋转隧道窑，实现了旋转运行的窑体与固定位置的污泥供给点之间的动态、精准对接，保证了污泥的连续、稳定供应。该系统通过从焙烧区段后段抽取高温余热，为污泥烘干提供了稳定高效的热源；烘干后的热风被引入冷却区段，并随窑内气流运动至高温的焙烧区段，利用窑内高温对废气中的臭气和病原体进行彻底分解，实现了废气的无害化处理，避免了二次污染，并且不会影响砖的烧制。上述技术特征协同作用，共同实现了对旋转隧道窑余热的梯级高效利用和污泥的低成本、无害化、资源化处置，最终达成了节能、环保、降耗的效果，并最终实现一个节能、环保、降耗、减排、创收的闭环循环工业系统。
Smart Images
Figure CN224850817U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a resource utilization system that utilizes the waste heat from brick making in a rotary tunnel kiln to dry sludge and uses the dried sludge as a raw material for brick making. It belongs to the intersection of solid waste resource utilization and kiln brick making. Background Technology
[0002] A rotary tunnel kiln is a furnace system used for brick making. It mainly consists of a circular track and an arc-shaped tunnel kiln running on the track. Its working principle is roughly as follows: brick blanks, which are pressed into shape by a blank-making machine, are stacked on the ground inside the running track of the tunnel kiln. The tunnel kiln runs along the circular track. During the operation, the brick blanks pass through the stacked brick blanks, thus "entering" the tunnel kiln and passing through different firing sections of the tunnel kiln in sequence to complete the firing. The finished bricks "come out" of the tunnel kiln.
[0003] Rotary tunnel kilns generate a large amount of high-temperature waste heat during the brick-making process. Currently, most of this waste heat is not fully utilized, resulting in huge energy waste and environmental thermal pollution.
[0004] Municipal sludge has a high water content (usually above 80%), making it difficult to treat and dispose of. Traditional thermal drying methods require large amounts of primary energy sources such as coal and natural gas, which are costly and pose a risk of secondary pollution; landfilling occupies land and can easily cause soil and groundwater pollution.
[0005] Currently, there are some technologies that utilize waste heat from brick making to assist in drying sludge and then use it for brick making. However, how to couple "using waste heat from brick making to dry sludge" into a rotary tunnel kiln system to achieve stable, efficient, safe, and environmentally friendly sludge drying, and ensure that the dried sludge does not affect the quality of the bricks (such as strength, durability, and environmental indicators) as a raw material for brick making, is a major technical challenge. At present, there is no practical solution in the industry. Summary of the Invention
[0006] In view of this, this utility model proposes a sludge resource utilization system based on the waste heat utilization of a rotary tunnel kiln. The aim is to use the high-temperature waste heat from the brick-making process of the rotary tunnel kiln to dry the sludge, and use the dried sludge as a raw material for brick making. An integrated system matching the dynamic operation of the rotary tunnel kiln is constructed to achieve efficient and stable recovery and utilization of the high-temperature waste heat of the kiln, while ensuring the environmental friendliness and operational reliability of the entire treatment process. This achieves the synergistic coupling of waste heat recovery, sludge resource utilization and brick production, thereby achieving the goals of energy saving, environmental protection and consumption reduction.
[0007] To achieve the above objectives, the present invention proposes the following technical solution: A sludge resource utilization system based on waste heat utilization in a rotary tunnel kiln includes: a rotary tunnel kiln, a sludge conveying unit, and a sludge drying unit, a waste heat collection unit, and a hot air recovery unit installed on the rotary tunnel kiln. The waste heat collection unit is connected between the roasting section of the rotary tunnel kiln and the sludge drying unit, and is used to extract high-temperature waste heat from the roasting section and send it to the sludge drying unit. The sludge drying unit is connected to the sludge conveying unit and is used to dry the sludge using the high-temperature waste heat. The hot air recovery unit is connected to the sludge drying unit and is used to recover the hot air after heat exchange with the sludge into the rotary tunnel kiln for high-temperature deodorization. The conveying unit includes a power unit, a first conveying pipe, a second conveying pipe, a storage area, and a feeding device. The power unit is used to pump the sludge to be treated into the first conveying pipe and then into the second conveying pipe. The storage area and the feeding device are mounted on the rotary tunnel kiln. The second conveying pipe is arranged in a ring above the rotary tunnel kiln, consistent with the running track of the rotary tunnel kiln, and has multiple discharge ports for feeding the sludge to be treated into the storage area when the rotary tunnel kiln runs to below the corresponding discharge port. The feeding device is connected between the storage area and the sludge drying unit for feeding the sludge to be treated from the storage area into the sludge drying unit.
[0008] Furthermore, the power unit of the sludge conveying unit is a pump installed in the sludge tank; the second conveying pipe is installed and fixed on a support frame; the first conveying pipe extends upward from the sludge tank to the second conveying pipe, with one end connected to the pump and the other end connected to the second conveying pipe.
[0009] Furthermore, the discharge port of the second conveying pipe is an openable and closable gate.
[0010] Furthermore, the rotary tunnel kiln is configured to operate on a circular track and includes a drying section, a preheating section, a calcining section, and a cooling section connected in sequence.
[0011] Furthermore, the waste heat collection unit includes an induced draft fan and a hot air conveyor belt. The induced draft fan is installed on the kiln top of the roasting section and is used to extract high-temperature waste heat from the roasting section and send it into the sludge drying unit from the inlet end of the sludge drying unit via the hot air conveyor belt. The feeding device of the sludge conveying unit is implemented by a screw conveyor. One end of the screw conveyor is connected to the storage area and the other end is connected to the inlet end of the sludge drying unit, and is used to screw-push the sludge from the storage area to the sludge drying unit.
[0012] Furthermore, the induced draft fan is used to extract high-temperature waste heat of 850°C to 900°C from the rear section of the roasting zone; preferably, it extracts high-temperature waste heat of about 850°C.
[0013] Furthermore, the sludge drying unit includes a drive device and a dryer, the drive device being able to drive the dryer to rotate; the sludge drying unit is able to dry the sludge to a moisture content of 10%~15%.
[0014] Furthermore, one end of the hot air recovery pipeline of the hot air recovery unit is connected to the outlet end of the sludge drying unit, and the other end is connected to the cooling section. It is used to send the hot air after heat exchange with the sludge to the cooling section so that the hot air can flow through the cooling section and enter the roasting section for high-temperature deodorization.
[0015] The beneficial effects of this utility model's technical solution are as follows: The sludge resource utilization system provided by this utility model integrates a waste heat collection unit, a sludge drying unit, and a hot air recovery unit onto a rotary tunnel kiln. It also innovatively designs a ring-shaped second conveying pipe coaxial with the kiln track and a matching feeding mechanism, matching the dynamically operating rotary tunnel kiln. This achieves dynamic and precise docking between the rotating kiln body and the fixed sludge supply point, ensuring a continuous and stable sludge supply. The system extracts high-temperature waste heat from the rear section of the firing zone, providing a stable and efficient heat source for sludge drying. The dried hot air is introduced into the cooling zone and moves with the kiln's airflow to the high-temperature firing zone, where the high temperature thoroughly decomposes odors and pathogens in the exhaust gas, achieving harmless treatment of the exhaust gas, avoiding secondary pollution, and not affecting brick firing. The synergistic effect of the above-mentioned technical features enables the efficient utilization of waste heat from rotary tunnel kilns in stages and the low-cost, harmless, and resource-based disposal of sludge, ultimately achieving energy conservation, environmental protection, and consumption reduction, and finally realizing a closed-loop circular industrial system that saves energy, protects the environment, reduces consumption, reduces emissions, and generates revenue.
[0016] In a further technical solution, a screw conveyor is used as the feeding device, which realizes a closed and stable conveying from the storage area to the drying unit, avoiding blockage and environmental pollution during the conveying process.
[0017] In a further technical solution, by connecting the outlet of the hot air recovery pipeline to the cooling section, a closed-loop air circulation path is formed under the action of the induced draft fan: the rear section of the roasting zone → induced draft fan → hot air conveyor belt → dryer → hot air recovery pipeline → cooling section → the rear section of the roasting zone. This ensures that the hot air containing pollutants must pass through the high-temperature area to be deodorized without the need for additional power, making the design more reasonable and efficient. At the same time, it also prevents harmful airflow after heat exchange with sludge from entering the air. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of a sludge resource utilization system based on the waste heat utilization of a rotary tunnel kiln, according to an embodiment of this utility model. Detailed Implementation
[0019] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. The embodiments provided are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.
[0020] This utility model embodiment provides a sludge resource utilization system based on the waste heat utilization of a rotary tunnel kiln, such as... Figure 1 As shown, the system includes: a rotary tunnel kiln 10, a sludge conveying unit, and a sludge drying unit, a waste heat collection unit, and a hot air recovery unit installed on the rotary tunnel kiln. The rotary tunnel kiln 10 is configured to operate on a circular track 20, and its kiln body includes a drying section, a preheating section, a calcination section, and a cooling section connected in sequence. Figure 1 In the illustrated embodiment, the kiln body of the rotary tunnel kiln operates along direction D1. A waste heat collection unit is connected between the roasting section and the sludge drying unit of the rotary tunnel kiln 10, used to extract high-temperature waste heat from the rear section of the roasting section (the rear section refers to the side near the cooling section, and the front section refers to the side near the preheating section) and send it to the sludge drying unit. The sludge drying unit is connected to the sludge conveying unit, used to dry the sludge using the high-temperature waste heat. A hot air recovery unit is connected to the sludge drying unit, used to recover the hot air after heat exchange with the sludge and return it to the rotary tunnel kiln for high-temperature deodorization. The sludge conveying unit includes a power unit 30, a first conveying pipe 31, a second conveying pipe 32, a storage area 33, and a feeding device 34, wherein the power unit 30 is used to pump the sludge to be treated into the first conveying pipe 31 and then into the second conveying pipe 32; the storage area 33 and the feeding device 34 are located on the kiln top of the rotary tunnel kiln 10. The second conveying pipe 32 is arranged in a ring above the rotary tunnel kiln in accordance with the running track 20 of the rotary tunnel kiln, and is provided with multiple discharge ports for discharging the sludge to be treated into the storage area 33 when the rotary tunnel kiln runs to the bottom of the corresponding discharge port; the feeding device 34 is connected between the storage area 33 and the sludge drying unit 40 for sending the sludge to be treated in the storage area 33 into the sludge drying unit 40 for drying.
[0021] Preferably, the system of this embodiment operates under a factory shed, which is supported by a large support frame. (Continue to refer to...) Figure 1The power unit 30 of the sludge conveying unit is a pump installed in the sludge tank. This pump can be, for example, a trailer-mounted concrete pump, with a power option of 55KW. Since the system of this invention processes sludge with a high water content, it is less likely to cause pipe blockage. Furthermore, the sludge can be filtered through a filter plug before entering the pump body to prevent blockage of the transport pipe. In case of blockage, the pipe can be disassembled for cleaning or even replaced directly. A second annular conveying pipe 32, coaxial with the track, is installed and fixed on the support frame. Multiple openable and closable gates 320 for discharging material are evenly spaced on this second conveying pipe 32. When the rotary tunnel kiln stops, the gates can be opened manually (an operating platform is provided on the kiln top for workers to stand on and operate from). Because the sludge pump is running, the sludge can be "squeezed out" and fall into the storage area 33. The rotary tunnel kiln operates in both running and stopped states throughout its entire process. In this embodiment of the invention, multiple gates are provided, and the storage area is relatively large compared to the gates. This design ensures that each time the rotary tunnel kiln stops, a corresponding gate is available to deliver sludge to the storage area. In some embodiments, to prevent sludge conveying pipe blockage, a pipe heating and high-pressure flushing return system can be installed; the pipes can even be replaced periodically or as needed. The finished brick blanks are transported to the inner area of the rotary tunnel kiln's track and stacked. As the kiln moves along the track, the brick blanks sequentially pass through the drying section, preheating section, firing section, and cooling section. Each stop of the kiln is to perform corresponding processing operations on the brick blanks in the corresponding section. For example, when the kiln initially operates, the first batch of brick blanks is in the drying section. The kiln remains stationary for a period of time, then moves to the preheating section and stops, while the second batch of brick blanks enters the drying section. After another period of time, the kiln continues to move until the first batch of brick blanks is in the firing section and stops, while the second batch is in the preheating section and the third batch enters the drying section; and so on. The rotary tunnel kiln itself requires a cycle of operation-stop-operation-stop during operation. This invention utilizes the time the kiln is stopped to collect sludge. Preferably, the first conveying pipe 31 and the second conveying pipe 32 are seamless steel pipes with a diameter of approximately 20 cm and a wall thickness of at least approximately 0.5 cm (the interior can be coated with an anti-sludge corrosion layer, which can be replaced as needed). The sludge pump pumps the sludge from the sludge tank into the first conveying pipe 31 and then into the second conveying pipe 32. The starting end of the first conveying pipe 31 is connected to the pump, and the end of the first conveying pipe 31 is connected to the second conveying pipe using a tee.
[0022] Continue to refer to Figure 1The waste heat collection unit includes an induced draft fan 51 and a hot air conveyor belt 52. The induced draft fan 51 is installed on the top of the kiln in the roasting section of the kiln body, and its exhaust port is sealed to an opening on the top of the kiln body. It is used to extract high-temperature waste heat of about 850°C from the rear section of the roasting section and send it into the sludge drying unit 40 through the inlet end of the hot air conveyor belt 52. The pipes of the waste heat collection port and the hot air conveyor belt are made of high-temperature and corrosion-resistant materials (such as 310S stainless steel lined with refractory material). Temperature sensors are installed at different locations in each section of the kiln body to collect the kiln temperature in real time. The temperature monitored by these sensors can be transmitted to the kiln control system in real time and can be displayed in real time on the system interface. In one embodiment of this invention, multiple temperature values were monitored in the drying section, ranging from tens of degrees to over 100 degrees Celsius; multiple temperatures were monitored in the preheating section, ranging from 200 to over 300 degrees Celsius; multiple temperatures were monitored in the calcination section, ranging from 700 to over 900 degrees Celsius; and multiple temperatures were monitored in the cooling section, ranging from 200 to over 300 degrees Celsius. It should be understood that the waste heat temperature is not limited to 850 degrees Celsius, but can be between 800 degrees Celsius and 950 degrees Celsius. The feeding device 34 of the sludge conveying unit can be implemented using a screw conveyor. One end of the screw conveyor is connected to the storage area 33, and the other end is connected to the inlet end of the sludge drying unit 40, used to screw-push the sludge from the storage area 33 to the sludge drying unit 40. The sludge drying unit 40 may specifically include a drive device (such as a motor) and a dryer. The drive device can drive the dryer to rotate (the specific drive principle is existing technology and will not be described in detail). The dryer has a spiral design inside, so it can achieve simultaneous rotation, spiral transport, and drying, thereby improving drying efficiency. In the sludge drying unit of this utility model embodiment, the sludge takes about 30 minutes from entering the dryer to exiting. It can dry municipal sludge with a moisture content of more than 80% to a moisture content of 10% to 15%. At the same time, the high temperature of the hot air can kill some pathogens in the sludge. Then the dried sludge is transported out via the dry sludge conveyor belt 70.
[0023] In some specific embodiments, two induced draft fans 51 can be installed, selected as fans with a power of approximately 45KW and an air volume of 34300~51500m³ / h. The induced draft fans extract high-temperature waste heat from the calcination section using negative pressure. The hot air, after heat exchange with the sludge in the dryer, is then sent back to the kiln under positive pressure via the hot air recovery pipe 60 connected to the end of the dryer. Due to the action of the induced draft fans, a closed-loop gas circulation path is formed: rear section of the calcination section → induced draft fan → hot air conveyor belt → dryer → hot air recovery pipe → cooling section → rear section of the calcination section. Since the high-temperature waste heat is extracted from the rear section of the calcination section, where the bricks have already undergone high-temperature firing, the extraction of waste heat will not affect the brick forming. The hot air after heat exchange with the sludge is recycled back into the kiln for high-temperature deodorization, removing some harmful substances volatilized from the sludge. Specifically, volatile organic compounds (VOCs) and sulfur / nitrogenous odorous gases contained in the hot air stream recovered after sludge drying are mostly removed by high temperatures after entering the later stage of the roasting zone. Heavy metals that are difficult to remove at high temperatures are solidified in the bricks under high-temperature roasting, ensuring that the leaching toxicity of heavy metals meets standards and is environmentally safe. The temperature of the hot air after heat exchange with the sludge has decreased to two to three hundred degrees Celsius, which will not disrupt the temperature gradient of the cooling zone (the temperature range of the cooling zone is 200-300 degrees Celsius) and will not affect the cooling of the bricks. Preferably, the hot air recovery pipeline is introduced from the side wall of the kiln in the cooling zone to minimize interference with the airflow and thermal regime. Simultaneously, since the airflow direction of the entire kiln is from the cooling zone to the drying zone, such as... Figure 1 As shown, an exhaust pipe is installed at the front end of the drying section near the inlet. The kiln flue gas is discharged after being treated by the desulfurization tower. The gas discharged from the desulfurization tower is monitored in real time, and according to the monitoring data, there are no exceedances.
[0024] After drying, the sludge undergoes pretreatment such as crushing and screening. It can then be used as a raw material for brick making, mixed with coal gangue, shale, etc., in a certain mass ratio (e.g., around 20%) for pressing brick blanks. The brick blanks are then transported back to the rotary tunnel kiln of this invention for firing, thus realizing the resource utilization of the sludge. This system, without affecting the production of the rotary tunnel kiln, fully utilizes waste heat to dry the sludge and uses it as a raw material for brick making, achieving low-cost resource utilization of the sludge. Furthermore, the entire process ensures compliance with environmental emission standards through dual treatment via hot air recovery and a desulfurization tower. It achieves the synergistic treatment of two major wastes—waste heat and sludge—eliminating thermal pollution from waste heat emissions and secondary pollution from sludge landfill, thus conforming to carbon neutrality policies. The technology is reliable in two ways: First, secondary hot air treatment followed by desulfurization ensures that harmful substances volatilized during the sludge drying process are treated, ensuring that emissions meet relevant environmental standards. Second, by rationally controlling the proportion of dried sludge added, it guarantees that the brick's compressive strength and other performance indicators meet national standards (e.g., MU10 or higher), and that high-temperature firing solidifies pollutants that are difficult to remove at high temperatures, such as heavy metals, within the brick, preventing leaching and ensuring environmental safety. This achieves seamless coupling between the original brick-making system and the sludge treatment system, two independent production systems, ensuring safe and stable operation.
[0025] The system of this embodiment currently maintains a stable sludge processing capacity of approximately 200 tons / day. The dried sludge is added to the brick-making raw materials at a mass ratio of about 20%. Samples of the fired bricks are sent to the Honghe Prefecture Quality and Technical Supervision Comprehensive Testing Center for testing according to the standard "GB / T 5101-2017 'Sintered Common Bricks'" (testing dates: January 10, 2025 to January 15, 2025), and they meet the standard requirements. Specific test items and results are shown in Table 1 below. Table 1. Attachments to the Test Report The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several equivalent substitutions or obvious modifications can be made without departing from the concept of the present invention, and all such modifications, with identical performance or use, should be considered within the protection scope of the present invention.
Claims
1. A sludge resource utilization system based on the waste heat utilization of a rotary tunnel kiln, characterized in that, include: A rotary tunnel kiln, a sludge conveying unit, and a sludge drying unit, a waste heat collection unit, and a hot air recovery unit installed on the rotary tunnel kiln; The waste heat collection unit is connected between the roasting section of the rotary tunnel kiln and the sludge drying unit, and is used to extract high-temperature waste heat from the roasting section and send it into the sludge drying unit; the sludge drying unit is connected to the sludge conveying unit, and is used to dry the sludge using the high-temperature waste heat; the hot air recovery unit is connected to the sludge drying unit, and is used to recover the hot air after heat exchange with the sludge into the rotary tunnel kiln for high-temperature deodorization. The sludge conveying unit includes a power unit, a first conveying pipe, a second conveying pipe, a storage area, and a feeding device. The power unit is used to pump the sludge to be treated into the first conveying pipe and then into the second conveying pipe. The storage area and the feeding device are located on the rotary tunnel kiln. The second conveying pipe is arranged in a ring above the rotary tunnel kiln in a manner consistent with the running track of the rotary tunnel kiln, and is provided with multiple discharge ports for discharging the sludge to be treated into the storage area when the rotary tunnel kiln runs to the position below the corresponding discharge port. The feeding device is connected between the storage area and the sludge drying unit, and is used to feed the sludge to be treated in the storage area into the sludge drying unit.
2. The sludge resource utilization and treatment system as described in claim 1, characterized in that: The power unit of the sludge conveying unit is a pump installed in the sludge tank; the second conveying pipe is installed and fixed on a support frame; the first conveying pipe extends upward from the sludge tank to the second conveying pipe, with one end connected to the pump and the other end connected to the second conveying pipe.
3. The sludge resource utilization and treatment system as described in claim 1 or 2, characterized in that: The discharge port of the second conveying pipe is an openable and closable gate.
4. The sludge resource utilization and treatment system as described in claim 1, characterized in that: The rotary tunnel kiln is configured to operate on a circular track and includes a drying section, a preheating section, a calcining section and a cooling section connected in sequence.
5. The sludge resource utilization and treatment system as described in claim 4, characterized in that: The waste heat collection unit includes an induced draft fan and a hot air conveyor belt. The induced draft fan is installed on the kiln top of the roasting section and is used to extract high-temperature waste heat from the roasting section and send it into the sludge drying unit from the inlet end of the sludge drying unit via the hot air conveyor belt. The feeding device of the sludge conveying unit is implemented by a screw conveyor. One end of the screw conveyor is connected to the storage area and the other end is connected to the inlet of the sludge drying unit, which is used to push the sludge in the storage area to the sludge drying unit.
6. The sludge resource utilization and treatment system as described in claim 5, characterized in that: The induced draft fan is used to extract high-temperature waste heat of 850℃~900℃ from the rear section of the roasting zone.
7. The sludge resource utilization and treatment system as described in claim 6, characterized in that: The sludge drying unit includes a drive device and a dryer. The drive device can drive the dryer to rotate. The sludge drying unit can dry the sludge to a moisture content of 10% to 15%.
8. The sludge resource utilization and treatment system according to any one of claims 5 to 7, characterized in that: The hot air recovery pipeline of the hot air recovery unit is connected at one end to the outlet end of the sludge drying unit and at the other end to the cooling section. It is used to send the hot air after heat exchange with the sludge to the cooling section so that the hot air can flow through the cooling section and enter the roasting section for high-temperature deodorization.