A hot water type waste heat recovery system for starch drying

Abstract

This application relates to the field of starch drying technology and discloses a hot water-type waste heat recovery system for starch drying, including a drying mechanism, a water tank assembly, and a heat exchanger. The drying mechanism includes a drying tank, and a drying ring is fixedly installed on the inner wall of the drying tank along its length. The inner wall of the drying ring is provided with a spiral cavity. This hot water-type waste heat recovery system for starch drying achieves a spiral flow path design of hot water within the cavity through the spiral cavity provided on the inner wall of the drying ring and the radially arranged inlet and outlet at the top and bottom ends. This extends the heat exchange time and enhances the heat conduction efficiency, ensuring uniform heating of the inner wall of the drying ring and effectively improving the uniformity of starch drying and the waste heat recovery utilization rate.

Description

Technical Field

[0001] This application relates to the field of starch drying technology, specifically a hot water-type waste heat recovery system for starch drying. Background Technology

[0002] In the starch production and processing process, the drying process is one of the most energy-intensive and critical steps. Traditional starch drying equipment often uses electric heating, steam heating, or direct combustion of fossil fuels, which not only has low energy utilization but also results in serious waste of waste heat.

[0003] An existing patent (publication number: CN220793683U) discloses a starch dryer with a waste heat recovery structure, which is equipped with a preheating chamber and a flue gas duct. When the device is working, the air is collected through the preheating chamber, and then the high-temperature flue gas generated by the generator set is introduced into the flue gas duct to preheat the air. This improves energy utilization efficiency, facilitates the subsequent air heating speed, helps to improve the processing efficiency of the device, effectively utilizes the waste heat of the exhaust gas, reduces the thermal pollution of the environment by waste heat, reduces the unit consumption of the product, and saves costs.

[0004] However, the aforementioned dryer preheats the air by introducing high-temperature flue gas into the flue gas duct, and then uses an intake fan to blow the air near the flue gas duct to the starch surface. However, the intake fan is located in a closed space, which can easily lead to uneven airflow distribution. The high wind speed at the upper air inlet causes hot air to flow out directly, while the insufficient air volume at the lower end creates a low-temperature zone, affecting the uniformity of starch drying. Secondly, the closed space restricts the airflow diffusion path, exacerbating starch dust accumulation on the fan blades and affecting the service life of the intake fan. Furthermore, the drifting dust can easily escape from the feed pipe. Utility Model Content

[0005] To address the shortcomings of existing technologies, this application provides a hot water-type waste heat recovery system for starch drying, which has advantages such as uniform drying and solves the problems mentioned in the background technology.

[0006] To achieve the above objectives, this application provides the following technical solution: a hot water type waste heat recovery system for starch drying, comprising a drying mechanism, a water tank assembly and a heat exchanger. The drying mechanism includes a drying tank, and a drying ring is fixedly installed on the inner wall of the drying tank along its length direction. The inner wall of the drying ring is provided with a spiral channel, and the top and bottom ends of the spiral channel are respectively fixedly connected to an inlet and an outlet arranged horizontally along the radial direction of the drying tank. The drying mechanism also includes a set of heat-conducting fin rings arranged linearly along the height of the drying tank. Each heat-conducting fin ring is integrally formed with the inner wall of the drying ring, and the end of each heat-conducting fin ring away from the inner wall of the drying tank is inclined downward. The drying mechanism also includes a stirring shaft, which is coaxially arranged with the drying tank. The top and bottom ends of the stirring shaft are rotatably connected to the inner top wall and inner bottom wall of the drying tank, respectively. A set of stirring blades is fixedly connected to the outer surface of the stirring shaft. Each stirring blade is provided with a scraping part at one end near the inner wall of the drying tank. Each scraping part contacts the upper surface and bottom of the heat-conducting fin ring that is close to it.

[0007] Furthermore, the water tank assembly includes a tank body, a liquid level sensor installed on the inner wall of the tank body along the height direction of the tank body, a filter installed on one side of the tank body, the input end of the filter being fixedly connected to the tank body, and the output end of the filter being connected to an external water supply pipeline.

[0008] The above solution uses filters to treat the circulating water, preventing scale buildup on the inner walls of the heat exchanger tube bundles and spiral channels, ensuring heat exchange efficiency, extending equipment lifespan, and reducing subsequent descaling and maintenance costs.

[0009] Furthermore, the heat exchanger is provided with a flue gas inlet, a flue gas outlet, a water inlet pipe, and a water outlet pipe. A first pipe is fixedly connected to one side of the housing, and the other end of the first pipe is fixedly connected to the water inlet pipe. A second pipe is fixedly connected to one end of the water outlet pipe, and the other end of the second pipe is fixedly connected to the water inlet. A third pipe is fixedly connected to one end of the water outlet pipe, and the third pipe is fixedly connected to one side of the housing.

[0010] Through the above scheme, the flue gas inlet is connected to the gas supply pipeline of the biogas direct-fired generator in the outside world to introduce high-temperature flue gas for heat exchange; the flue gas outlet is connected to the external waste gas purification and treatment system to introduce the low-temperature flue gas after heat exchange and cooling into the purification device for treatment to meet the standards before being discharged, thus realizing waste heat recovery and environmentally friendly emissions.

[0011] Furthermore, a pump body is installed at the middle end of both the first and third pipe bodies.

[0012] The above solution provides circulating power, ensuring that hot water forms a stable circulating flow field between the heat exchanger, the spiral cavity, and the water tank assembly.

[0013] Furthermore, flow sensors are installed in the middle of both the second and third pipe bodies.

[0014] The above solution enables real-time monitoring of water flow in the pipeline, controls the circulating water volume, and ensures continuous water flow inside the spiral cavity.

[0015] Furthermore, a support frame is installed at the bottom of the drying tank, and a discharge pipe is fixedly connected to the bottom of the drying tank.

[0016] The above solution achieves stable support for the drying tank.

[0017] Furthermore, a closed shaft is rotatably connected to the inner wall of the discharge pipe, a closed plate is fixedly connected to the outer surface of the closed shaft, and a sealing gasket is fixedly connected to one end of the closed plate.

[0018] The above scheme drives the closed shaft to rotate, thereby driving the closed plate and high-temperature resistant rubber gasket to complete the opening and closing action of the discharge pipe.

[0019] Compared with the prior art, the technical solution of this application has the following beneficial effects: This hot water-type waste heat recovery system for starch drying achieves a spiral flow path design for hot water within the drying ring by using a spiral cavity set in the inner wall of the drying ring and radially arranged inlet and outlet at the top and bottom. This extends the heat exchange time and enhances the heat conduction efficiency, ensuring uniform heating of the inner wall of the drying ring and effectively improving the uniformity of starch drying and the waste heat recovery utilization rate. By using heat-conducting fins integrally formed on the inner wall of the drying ring and linearly arranged along the height of the tank, and with their downward tilting design away from the inner wall of the tank, the natural flow and full contact heat transfer of starch during the drying process are achieved, avoiding dead corners where starch accumulates on the fin surface and ensuring continuous and efficient heat conduction performance. By continuously contacting the scraping part at the end of the stirring blade on the stirring shaft with the upper surface of the heat-conducting fin ring, the starch adhering to the fin surface is continuously scraped off during the rotation process. This not only prevents heat conduction blockage but also avoids starch caramelization caused by local overheating. At the same time, it can achieve uniform stirring of starch and ensure that it is heated evenly. By installing a filter within the water tank assembly, the circulating water is filtered, effectively preventing scale buildup on the heat exchanger tube bundle and the inner wall of the spiral cavity. This ensures heat exchange efficiency, extends equipment lifespan, and reduces subsequent descaling and maintenance costs. The installation of pumps in the first and third tube bodies, along with flow sensors in the second and third tube bodies, enables stable circulation of hot water between the heat exchanger, spiral cavity, and water tank assembly. Real-time monitoring of water flow and control of the circulating water volume within the pipeline ensure continuous water flow and stable heat exchange within the spiral cavity. Attached Figure Description

[0020] Figure 1 This is a three-dimensional schematic diagram of the overall structure of this application; Figure 2 This is a front view of the overall structure of this application; Figure 3 This is a cross-sectional view of the drying mechanism structure in this application; Figure 4 This is a structural diagram of the stirring blade in this application; Figure 5 This is a structural diagram of the drying ring in this application; Figure 6This is a structural diagram of the material discharge pipe in this application.

[0021] In the picture: 1. Drying mechanism; 101. Drying tank; 102. Drying ring; 103. Spiral cavity; 104. Water inlet; 105. Water outlet; 106. Heat-conducting fin ring; 107. Stirring shaft; 108. Stirring blade; 109. Scraper; 2. Water tank assembly; 201. Tank body; 202. Liquid level sensor; 203. Filter; 3. Heat exchanger; 301. Flue gas inlet; 302. Flue gas outlet; 303. Water inlet pipe; 304. Water outlet pipe; 305. First tube body; 306. Second tube body; 307. Third tube body; 4. Pump body; 5. Flow sensor; 6. Support frame; 7. Enclosed shaft; 8. Enclosed plate; 9. Sealing gasket; 10. Discharge pipe. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] Please see Figures 1-6 This embodiment discloses a hot water-type waste heat recovery system for starch drying, comprising a drying mechanism 1, a water tank assembly 2, and a heat exchanger 3. The drying mechanism 1 includes a drying tank 101, with a feed pipe (not shown in the figure) fixedly connected to the top of the drying tank 101. A drying ring 102 arranged along its length is fixedly installed on the inner wall of the drying tank 101. A spiral cavity 103 is provided on the inner wall of the drying ring 102. The top and bottom of the spiral cavity 103 are respectively fixedly connected to an inlet 104 and an outlet 105 arranged horizontally along the radial direction of the drying tank 101. This design realizes a spiral flow path of hot water in the spiral cavity 103, prolonging the heat exchange time and enhancing the heat conduction efficiency, so that the inner wall of the drying ring 102 is uniformly heated, effectively improving the uniformity of starch drying and the waste heat recovery utilization rate.

[0024] A support frame 6 is installed at the bottom of the drying tank 101. A discharge pipe 10 is fixedly connected to the bottom of the drying tank 101. A closed shaft 7 is rotatably connected to the inner wall of the discharge pipe 10. A closed plate 8 is fixedly connected to the outer surface of the closed shaft 7. A sealing gasket 9 is fixedly connected to one end of the closed plate 8. The sealing gasket 9 is made of high-temperature resistant rubber. One end of the closed shaft 7 is fixedly connected to the output end of an external motor. The motor drives the closed shaft 7 to rotate, thereby driving the closed plate 8 and the high-temperature resistant rubber sealing gasket 9 to complete the opening and closing action of the discharge pipe 10. The drying mechanism 1 also includes a set of heat-conducting fin rings 106 arranged linearly along the height direction of the drying tank. Each heat-conducting fin ring 106 is integrally formed with the inner wall of the drying ring 102. The end of each heat-conducting fin ring 106 away from the inner wall of the drying tank 101 is inclined downward, which can prevent starch from falling on the heat-conducting fin ring 106 and forming a dead corner. The downwardly inclined flow guiding structure can guide the starch to slide naturally to the discharge area at the bottom of the tank, while ensuring sufficient contact and heat transfer between the fins and the starch, maintaining efficient heat conduction performance.

[0025] The drying mechanism 1 also includes a stirring shaft 107. The top end of the stirring shaft 107 is fixedly connected to the external motor output end. The stirring shaft 107 is coaxially arranged with the drying tank 101. The top and bottom ends of the stirring shaft 107 are rotatably connected to the inner top wall and inner bottom wall of the drying tank 101, respectively. A set of stirring blades 108 are fixedly connected to the outer surface of the stirring shaft 107. Each stirring blade 108 is provided with a scraping part 109 at one end near the inner wall of the drying tank 101. Each scraping part 109 contacts the upper surface and bottom of the heat-conducting fin ring 106 that is close to it. During the rotation, the starch attached to the surface of the fin is continuously scraped off, which not only prevents heat conduction blockage but also avoids starch caramelization caused by local overheating, ensuring the long-term stable operation of the system.

[0026] The water tank assembly 2 includes a tank body 201. A liquid level sensor 202 is installed on the inner wall of the tank body 201 along the height direction of the tank body 201. A filter 203 is installed on one side of the tank body 201. The input end of the filter 203 is fixedly connected to the tank body 201, and the output end of the filter 203 is connected to the external water supply pipeline. The filter 203 filters the circulating water to prevent scale from depositing and forming on the inner wall of the heat exchanger 3 tube bundle and spiral cavity 103, ensuring heat exchange efficiency and extending the service life of the equipment, while reducing the cost of subsequent descaling maintenance. The heat exchanger 3 is respectively provided with a flue gas inlet 301, a flue gas outlet 302, a water inlet pipe 303, and a water outlet pipe 304. The outlet 301 is connected to the gas supply pipeline of the external biogas direct-fired generator, introducing high-temperature flue gas for heat exchange; the flue gas outlet is connected to the external waste gas purification system, which guides the low-temperature flue gas after heat exchange and cooling into the purification device for treatment to meet standards before discharge, realizing waste heat recovery and environmentally friendly emissions. One side of the box 201 is fixedly connected to the first pipe 305, and the other end of the first pipe 305 is fixedly connected to the water inlet pipe 303. One end of the water outlet pipe 304 is fixedly connected to the second pipe 306, and the other end of the second pipe 306 is fixedly connected to the water inlet 104. One end of the water outlet 105 is fixedly connected to the third pipe 307, and the third pipe 307 is fixedly connected to one side of the box 201.

[0027] Pumps 4 are installed at the middle of the first pipe body 305 and the third pipe body 307 to provide circulation power and ensure that hot water forms a stable circulation flow field between the heat exchanger 3, the spiral cavity 103 and the water tank assembly 2. Flow sensors 5 are installed in the middle of the second pipe body 306 and the third pipe body 307 to realize real-time monitoring of water flow in the pipeline, control the circulation water volume, and ensure continuous flow of water inside the spiral cavity 103.

[0028] The working principle of the above embodiment is as follows: When the system starts, the pump body 4 of the first pipe 305 and the third pipe 307 runs synchronously, driving the water in the water tank assembly 2 to enter the inlet pipe 303 of the heat exchanger 3 through the first pipe 305. At this time, the high-temperature flue gas generated by the biogas direct combustion generator is injected into the heat exchanger 3 through the flue gas inlet 301 and undergoes reverse heat exchange with the water in the pipe. The hot water is heated to the set temperature, and at the same time, the low-temperature flue gas enters the exhaust gas purification system through the flue gas outlet for treatment and is discharged after meeting the standards. The preheated hot water enters the top inlet 104 of the spiral cavity 103 of the drying ring 102 through the second pipe 306. The hot water flows downward in a spiral shape along the axial direction of the drying tank 101, extending the heat exchange path with the inner wall of the tank. The heat-conducting fin ring 106 is integrally formed with the inner wall of the drying ring 102. Its downward inclined structure ensures that the starch and fins are in full contact for heat transfer, and avoids the accumulation of materials on the surface of the fins. The motor drives the stirring shaft 107. The rotating agitator blade 108 continuously scrapes the surface of the heat-conducting fin ring 106 with its scraping part 109 at the end. When starch adheres to the fins, the scraping part 109 peels it off through physical contact, preventing heat conduction blockage. At the same time, the rotation of the agitator blade 108 stirs the material in the tank, achieving the purpose of drying the starch. The flow sensor 5 monitors the water flow of the second tube 306 and the third tube 307 in real time, dynamically adjusts the speed of the pump body 4, and reduces the fluctuation of the circulating water volume. The liquid level sensor 202 built into the water tank assembly 2 monitors the water level. When the water level is lower than the safety threshold, it triggers automatic water replenishment. The filter 203 effectively intercepts calcium and magnesium ions and impurities in the water, controls the water hardness to below 50ppm, avoids scaling of the heat exchanger 3 and the spiral cavity 103, and ensures heat exchange efficiency. After drying, the motor drives the closed shaft 7 to rotate, and the closed plate 8 drives the high-temperature resistant rubber sealing gasket 9 to open the discharge pipe 10, realizing the discharge of the material.

[0029] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0030] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A hot water-type waste heat recovery system for starch drying, comprising a drying mechanism (1), a water tank assembly (2), and a heat exchanger (3), characterized in that: The drying mechanism (1) includes a drying tank (101), and a drying ring (102) is fixedly installed on the inner wall of the drying tank (101) along its length direction. The inner wall of the drying ring (102) is provided with a spiral cavity (103), and the top and bottom ends of the spiral cavity (103) are respectively fixedly connected to a water inlet (104) and a water outlet (105) arranged horizontally along the radial direction of the drying tank (101). The drying mechanism (1) also includes a set of heat-conducting fin rings (106) arranged linearly along the height direction of the drying tank. Each heat-conducting fin ring (106) is integrally formed with the inner wall of the drying ring (102). The end of each heat-conducting fin ring (106) away from the inner wall of the drying tank (101) is inclined downward. The drying mechanism (1) also includes a stirring shaft (107), which is coaxially arranged with the drying tank (101). The top and bottom ends of the stirring shaft (107) are rotatably connected to the inner top wall and inner bottom wall of the drying tank (101), respectively. A set of stirring blades (108) are fixedly connected to the outer surface of the stirring shaft (107). Each stirring blade (108) is provided with a scraping part (109) at one end near the inner wall of the drying tank (101). Each scraping part (109) is in contact with the upper surface and bottom of the heat-conducting fin ring (106) that is close to it.

2. The hot water-type waste heat recovery system for starch drying according to claim 1, characterized in that: The water tank assembly (2) includes a tank body (201), a liquid level sensor (202) installed on the inner wall of the tank body (201) along the height direction of the tank body (201), a filter (203) installed on one side of the tank body (201), the input end of the filter (203) is fixedly connected to the tank body (201), and the output end of the filter (203) is connected to the external water supply pipeline.

3. A hot water-type waste heat recovery system for starch drying according to claim 2, characterized in that: The heat exchanger (3) is provided with a flue gas inlet (301), a flue gas outlet (302), a water inlet pipe (303) and a water outlet pipe (304). A first pipe (305) is fixedly connected to one side of the housing (201), and the other end of the first pipe (305) is fixedly connected to the water inlet pipe (303). A second pipe (306) is fixedly connected to one end of the water outlet pipe (304), and the other end of the second pipe (306) is fixedly connected to the water inlet (104). A third pipe (307) is fixedly connected to one end of the water outlet (105), and the third pipe (307) is fixedly connected to one side of the housing (201).

4. A hot water-type waste heat recovery system for starch drying according to claim 3, characterized in that: Pump bodies (4) are installed at the middle ends of the first pipe body (305) and the third pipe body (307).

5. A hot water-type waste heat recovery system for starch drying according to claim 4, characterized in that: Flow sensors (5) are installed in the middle of both the second pipe body (306) and the third pipe body (307).

6. A hot water-type waste heat recovery system for starch drying according to claim 1, characterized in that: The bottom of the drying tank (101) is equipped with a support frame (6), and the bottom of the drying tank (101) is fixedly connected to a discharge pipe (10).

7. A hot water-type waste heat recovery system for starch drying according to claim 6, characterized in that: The inner wall of the discharge pipe (10) is rotatably connected to a closed shaft (7), and a closed plate (8) is fixedly connected to the outer surface of the closed shaft (7). A sealing gasket (9) is fixedly connected to one end of the closed plate (8).

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