Efficient heat exchange and drying module and heat exchange and drying system using the same

Abstract

The present application provides an efficient heat exchange and drying module and a heat exchange and drying system applying the module, including a fan system, a heat exchange system, a secondary heat exchange device, a dehumidification rotor, a primary heat exchange device and a drying box body; through a closed circulating air system loop, high-temperature and high-humidity air can be processed and recycled to re-dry materials, so as to solve the problems of low efficiency and high energy consumption in the drying processes of products such as sludge and food; the secondary heat exchange device is an indirect evaporative cooling heat exchanger, which improves the heat exchange efficiency through secondary air and cooperates with a water distributor to further cool and dehumidify the circulating air, so that the temperature of the circulating air is reduced to a suitable temperature for further dehumidification by the dehumidification rotor.

Description

Technical Field

[0001] This application mainly relates to the technical field of drying equipment, and particularly relates to an efficient heat exchange drying module and a heat exchange drying system applying this module. Background Art

[0002] Most of the current methods used in crawler-type sludge drying equipment are to heat the air inside a closed drying box, use high-temperature air to dry out the moisture in the sludge, then cool and condense the high-humidity air for dehydration treatment, and then heat the air for continuous circulation. In this way, the sludge enters the drying equipment from the inlet, passes through the crawler to the outlet, and by adjusting the crawler length, the crawler traveling speed, and the air heating temperature, the sludge can reach the required dryness.

[0003] There are mainly two drying systems in the market for crawler-type drying equipment. One is to use a heat pump system, where the condenser heats the air to the required temperature and the evaporator cools the air, and the moisture condenses; the other is to use hot water or steam to heat the air and use a cooling tower cold water heat exchanger to cool the air for circulation.

[0004] Then improving the drying efficiency can shorten the drying time or reduce the volume of the drying equipment. In places where multiple drying equipment are used, the number of equipment can be reduced, and the energy consumption can be lowered.

[0005] The Chinese utility model patent has been published, with the application number CN201820638118.0 and the patent name: A sludge drying heat pump system. The condensation process of the refrigerant in the heat pump system is completed through two-stage condensers connected in series. A plate heat exchanger is arranged between the condenser and the evaporator for heat exchange to realize the utilization of the circulating return air and dry the sludge. However, in the heat pump system, increasing the condensation end temperature and decreasing the evaporation end temperature are restricted by the characteristics of the compressor and the refrigerant, and at the same time, the COP of the system will be reduced, and the energy-saving effect cannot be achieved. Further improvement of the heat pump technology is required to realize this.

[0006] The Chinese utility model patent has been published, with the application number CN201621298424.1 and the patent name: A high-temperature dehumidification dryer. A water coil is added to the circulating pipeline, and the water coil is arranged between the fan and the regenerator or between the regenerator and the evaporator to pre-cool the humid and hot air, which can improve the processing capacity of the equipment for high-temperature and high-humidity air. However, in the system using steam (hot water) heating, increasing the heating temperature can be achieved, but it will bring an increase in energy consumption; due to the limitation of the heat exchange efficiency of the cooling tower water temperature and the surface cooler heat exchanger, the air temperature cannot continue to drop to a certain extent, and at this time, the air temperature is still relatively high, and the corresponding humidity is also high, which affects the drying efficiency to a certain extent and increases the cost. Summary of the Invention

[0007] In view of the above defects of the prior art, the present application provides an efficient heat exchange and drying module and a heat exchange and drying system applying this module, which solves the problems of low efficiency and high energy consumption existing in the drying process of products such as sludge and food by forming a closed circulating air system loop; when the upper limit of the heating temperature and the lower limit of the refrigeration temperature of the existing equipment are limited in actual application, with the help of a special high-efficiency heat exchanger and a high-efficiency dehumidification rotary wheel, the humidity of the circulating air supply section is reduced, and the drying efficiency is significantly improved.

[0008] The present application provides an efficient heat exchange and drying module, including a fan system, a temperature control system, a secondary heat exchange device, a dehumidification rotary wheel, a primary heat exchange device and a drying box;

[0009] The fan system includes a first fan and a second fan, which provide air flow power for the module;

[0010] The temperature control system includes a first cooling device and a first heating device, which cooperate with the secondary heat exchange device and the dehumidification rotary wheel to provide low-humidity and high-temperature drying gas;

[0011] It also includes a drying circulating air path, and the circulating air sequentially passes through the first fan, the first cooling device, the secondary heat exchange device, the treatment area of the dehumidification rotary wheel, the primary heat exchange device, the second fan, the first heating device, the drying box, the primary heat exchange device, and then enters the first fan to start circulating;

[0012] It also includes a regeneration circulating air path, and the regeneration air sequentially passes through the first fan, the first cooling device, the secondary heat exchange device, the treatment area of the dehumidification rotary wheel, the regeneration area of the dehumidification rotary wheel, the primary heat exchange device, and then enters the first fan to start circulating.

[0013] Further preferably, the secondary heat exchange device is an indirect evaporative cooling heat exchanger; the indirect evaporative cooling heat exchanger is also provided with a water distributor.

[0014] Further preferably, the temperature control system adopts a steam heating system.

[0015] Further preferably, the first cooling device is a cold water coil; the first heating device is a steam coil.

[0016] Further preferably, the temperature control system adopts a heat pump system.

[0017] Further preferably, the first cooling device is an evaporator; the first heating device is a condenser.

[0018] Further preferably, it also includes a filter; the circulating air discharged from the drying box enters the filter for filtration and then enters the primary heat exchange device for heat exchange.

[0019] Further preferably, the recycled air after drying the drying box and the regeneration air passing through the regeneration area of the dehumidification wheel converge and then flow into the plate heat exchanger for heat exchange and cooling treatment.

[0020] Further preferably, the primary heat exchange device is a plate heat exchanger.

[0021] A heat exchange and drying system includes production equipment and the above-mentioned high-efficiency heat exchange and drying module connected to the production equipment.

[0022] Advantages of the present application: A special heat exchanger, which should be understood as an indirect evaporative cooling heat exchanger and a dehumidification wheel, is added to the closed air system loop forming a cycle to further reduce the humidity of the recycled air supply section and improve the drying efficiency. The primary inlet air of the indirect evaporative cooling heat exchanger is recycled air, and the secondary inlet air is ambient air. The secondary inlet air evaporates and absorbs heat through spraying water to enhance heat transfer, making the temperature reduction effect of the heat exchanger remarkable, and enabling the primary air temperature to reach the appropriate temperature required to enter the dehumidification wheel. Then, the moisture in the recycled air is adsorbed by the dehumidification wheel to reduce the humidity of the recycled air, and the regeneration air desorbs the dehumidification wheel, enabling the air to circulate cyclically and continuously obtaining dry recycled air. The dry air is heated and sent into the drying box to dry sludge or other materials. At the same drying temperature, the air is drier with lower humidity, and the moisture content of the air can be reduced to half or even lower than that of the original equipment. The sludge drying effect and drying rate are greatly improved, which can be increased by about 30%-50%. Description of the Drawings

[0023] Figure 1 It is a schematic structural diagram of the high-efficiency heat exchange and drying module of the embodiment of the present application;

[0024] Figure 2 It is a schematic diagram of the air flow direction of the indirect evaporative cooling heat exchanger of the embodiment of the present application;

[0025] Figure 3 It is a schematic diagram of the air flow direction of the dehumidification wheel of the embodiment of the present application;

[0026] Figure 4 It is a schematic structural diagram of the high-efficiency heat exchange and drying module of the present application applied to a sludge drying device;

[0027] In the figure,

[0028] 1. First fan; 2. First cooling device; 3. Secondary heat exchange device, 31. Primary air, 32. Secondary air; 4. Dehumidification wheel, 41. Treatment area, 42. Regeneration area, 43. Rotor frame; 5. Primary heat exchange device; 6. Second fan; 7. First heating device; 8. Drying box; 9. Filter; 10. Water distributor; 11. Second heating device. Detailed Embodiments

[0029] The present utility model will be described in detail below with reference to the accompanying drawings. The description in this part is only exemplary and explanatory, and should not have any restrictive effect on the protection scope of the present application.

[0030] The present application provides an efficient heat exchange and drying module and a heat exchange and drying system applying the module. By means of a temperature control system cooperating with a secondary heat exchange device 3 and a dehumidifying rotor 4, the dehumidifying and cooling function of the circulating air is enhanced, thereby improving the heat exchange and drying efficiency of the entire module. The air is conveyed by a fan system to ensure the normal operation of the circulating air path.

[0031] One of its implementation manners is that the temperature control system adopts a steam heating system. The temperature control system includes a first cooling device 2 and a first heating device 7. Specifically, the first cooling device 2 is a cold water coil, and the first heating device 7 is a steam coil. The fan includes a first fan 1 and a second fan 6. Specifically, the first fan 1 is a circulating fan, and the second fan 6 is a supply fan.

[0032] Specifically, this implementation manner includes two circulating air paths. The first circulating air path is a drying circulating air path, and the second circulating air path is a regeneration circulating air path. The two circulating air paths share a primary heat exchange device 5, a first fan 1, a first cooling device 2, a secondary heat exchange device 3, and a dehumidifying rotor 4 that are connected in sequence.

[0033] As Figure 1 shown by the hollow arrow, it is the drying circulating air path. The circulating air of the drying air path flows out from the first fan 1 and is first preliminarily cooled by the first cooling device 2, and then further cooled by the secondary heat exchange device 3. The temperature of the air further cooled by the secondary heat exchange device 3 is suitable for passing through the dehumidifying rotor 4. Then, it passes through the treatment area of the dehumidifying rotor 4, and the dehumidifying rotor 4 adsorbs the moisture in the circulating air to reduce the air humidity. The circulating air with reduced temperature and humidity then enters the primary heat exchange device 5 for heat exchange and temperature rise. The continuously heated dry circulating air is sent into the first heating device 7 by the second fan 6. The first heating device 7 heats the dry circulating air, and the heated dry circulating air is sent into the drying box body 8 to dry the materials on the equipment in the drying box body 8. The circulating air discharged from the drying box body 8 has a higher air humidity because it has absorbed the moisture of the materials, and becomes high-temperature and high-humidity air. At this time, the high-temperature and high-humidity air enters the primary heat exchange device 5 for heat exchange, and then passes through the first fan 1, the first cooling device 2, the secondary heat exchange device 3, and the dehumidifying rotor 4 again for cooling and dehumidification, and so on in a cycle, which is the drying circulating air path.

[0034] As Figure 1As shown by the solid arrow, it is the regeneration circulation air path. After the air in the regeneration circulation air path passes through the treatment areas of the first fan 1, the first cooling device 2, the secondary heat exchange device 3, and the dehumidification rotor 4 which are connected in sequence, it is heated by the second heating device 11 to become relatively high-temperature air. In this embodiment, the second heating device 11 is a steam coil. The relatively high-temperature air enters the regeneration area of the dehumidification rotor 4, causing the dehumidification rotor 4 to desorb at high temperature. Moisture enters the regeneration air, and the rotor becomes dry again. In this way, when the dehumidification rotor 4 rotates continuously, it adsorbs in the treatment area and desorbs in the regeneration area to regain the adsorption capacity, and can dry the treated air cyclically. The regeneration air passing through the regeneration area of the dehumidification rotor 4, after desorbing the dehumidification rotor 4, converges with the circulating air discharged from the drying box body 8 and flows into the primary heat exchange device 5 for heat exchange and cooling treatment. The air after the cooling treatment by the primary heat exchange device 5 enters the first fan 1, the first cooling device 2, the secondary heat exchange device 3, and the dehumidification rotor 4 again in sequence to complete the cycle.

[0035] The air in the two air paths in the primary heat exchange device 5 exchanges heat with each other: the high-temperature air discharged from the drying box body 8 exchanges heat with the low-temperature air discharged from the treatment area of the dehumidification rotor 4. That is, the low-temperature air discharged from the treatment area of the dehumidification rotor 4 exchanges heat with the high-temperature air through the primary heat exchange device 5 and is heated and then sent into the first heating device 7 by the second fan 6; in the other air path, the high-temperature air discharged from the drying box body 8 exchanges heat with the low-temperature air through the primary heat exchange device 5 and is cooled and then sent into the first cooling device 2 by the first fan 1 again. In this embodiment, specifically, the primary heat exchange device 5 is a plate heat exchanger.

[0036] In this embodiment, specifically, the secondary heat exchange device 3 is an indirect evaporative cooling heat exchanger. As Figure 2 shown, the indirect evaporative cooling heat exchanger includes two-direction airflows, namely the primary air 31 and the secondary air 32. The primary air 31 is the mixed air of the two circulation air paths. After being discharged from the first cooling device 2, it enters the indirect evaporative cooling heat exchanger and then enters the treatment area of the dehumidification rotor 4 after being discharged from the indirect evaporative cooling heat exchanger. The secondary air 32 is ambient air, and the air direction is perpendicular to that of the primary air 31. Preferably, a water distributor 10 is also provided on the indirect evaporative cooling heat exchanger. In this embodiment, the primary air 31 enters the heat exchanger tubes, and the secondary air 32 passes outside the heat exchanger tubes. The secondary air 32 is simultaneously sprayed with liquid water mist by the water distributor 10. The water mist evaporates and absorbs heat in the secondary air 32, further cooling the secondary air 32, which can increase the temperature difference with the primary air 31 and enhance the heat exchange effect. The heat exchanger itself increases the heat exchange efficiency by means of strengthening heat transfer, causing the temperature of the primary air 31 to drop significantly. When the temperature of the primary air 31 reaches the dew point temperature (condensation temperature), condensed water will also flow out of the primary air 31, reducing the temperature and moisture content of the mixed air of the two circulation air paths so as to enter the treatment area of the dehumidification rotor 4 for further dehumidification treatment.

[0037] In this embodiment, specifically, the dehumidification rotor 4 includes a treatment area 41 and a regeneration area 42. As Figure 3 shown: The dehumidification rotor 4 is arranged on the rotor frame 43. During operation, the dehumidification rotor 4 rotates continuously. When the dehumidification rotor 4 is working, it is divided into two separated areas relying on the air ducts. One is the treatment area 41, and the other is the regeneration area 42. The ratio of the treatment area 41 to the regeneration area 42 of the dehumidification rotor is 3:1. The treatment area 41 and the regeneration area 42 are fixed areas formed relying on the air ducts. As Figure 3 shown, the two circulating air paths indicated by the hollow arrow and the solid arrow pass through the treatment area 41 of the dehumidification rotor 4 for dehumidification treatment; and the regeneration air indicated by the solid arrow passes through the regeneration area 42 of the dehumidification rotor 4 for desorption treatment of the dehumidification rotor 4. As the dehumidification rotor 4 rotates, the functions of the corresponding areas of the dehumidification rotor 4 are alternately changed. When the corresponding area of the dehumidification rotor 4 passes through the treatment area 41, it dehumidifies the two circulating air paths, adsorbing the moisture in the air of the two circulating air paths. The corresponding area of the dehumidification rotor 4 that has absorbed the moisture, as the dehumidification rotor 4 rotates, turns to the regeneration area 42 and is desorbed by the regeneration air indicated by the solid arrow, and the moisture enters the air again, and the dehumidification rotor 4 returns to the dry state. In this cycle, it is ensured that the dehumidification rotor 4 can adsorb in the treatment area 41 and complete desorption in the regeneration area 42, regain the adsorption ability, and continuously dry the circulating air in a cycle.

[0038] Preferably, a second heating device 11 is further included. A part of the air after being treated by the dehumidification rotor 4 enters the regeneration area 42 of the dehumidification rotor 4 after being heated by the second heating device 11. The heated air is relatively high-temperature and dry air, which can desorb the corresponding area of the dehumidification rotor 4 that has adsorbed moisture, make the dehumidification rotor 4 become dry again, and regain the adsorption ability to ensure its continuous adsorption treatment of the circulating air. Specifically, the second heating device 11 can be a steam coil.

[0039] In this embodiment, the drying box body 8 at least includes a production device inside the box. The production device can be specifically embodied as a conveying integration. The conveying integration is a conveying device for the materials to be dried inside the box, which can be a conveyor belt device, and at least one conveyor belt device is provided. Specifically, the conveying device is also provided with a feeding port and a discharging port, and the feeding port and the discharging port are respectively arranged at both ends of the conveying device. As Figure 4As shown, this is a schematic diagram of the drying module used in a sludge drying device (the first fan 1, the second fan 6, the first cooling device 2, and the second heating device 11 are not shown in the figure), and the arrows in the figure indicate the air flow direction of the drying air path. Inside the drying box 8, three stacked conveyor belt devices are arranged. The conveyor belt devices carry the sludge to be dried, which is sequentially conveyed from the feeding port of the top conveyor belt device to the bottom conveyor belt, and the dried sludge is then conveyed from the discharging port to the next process. The application of this heat exchange drying module is not limited to sludge drying devices, but can also be used in food drying devices.

[0040] In this embodiment, at least one first heating device 7 is provided. Specifically, as Figure 4 shown, at least two first heating devices 7 can be connected in series (3 are shown in the figure), which improves the overall heating efficiency of the circulating air, and thus improves the drying efficiency of the materials in the drying box 8.

[0041] In this embodiment, a filter 9 is also included. After the circulating air is discharged from the drying box 8, since it dries the materials in the drying box 8, it adsorbs a large amount of moisture and also a large amount of impurities, and needs to be filtered by the filter 9 to filter out particulate impurities and impurities with larger volumes, so as to improve the purity of the circulating air.

[0042] In this embodiment, preferably, the first fan 1 and the second fan 6 are centrifugal fans, and are not limited to the above form.

[0043] In another embodiment of the present application, the temperature control system adopts a heat pump system, which includes a first cooling device 2 and a first heating device 7. In this embodiment, specifically, the first cooling device 2 is an evaporator, and the first heating device 7 and the second heating device 11 are condensers. In this embodiment, other parts are the same as those in the previous embodiment, and will not be described in detail here.

[0044] In some embodiments, a temperature testing device can also be added to the air path of this module to monitor the drying temperature. The temperature testing device is arranged between the second fan 6 and the drying box 8 to detect the temperature of the drying air, so as to adapt to the drying temperatures required by different materials.

[0045] For the convenience of description, the "high temperature", "high humidity", "low temperature", and "low humidity" described in this application are all relative results after comparing the circulating air with the outside air.

[0046] It should be noted that the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0047] The embodiments of the present application described above do not constitute a limitation to the protection scope of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the protection scope of the claims of the present application.

Claims

1. An efficient heat exchange and drying module, comprising a fan system, a temperature control system, a secondary heat exchange device, a dehumidification rotor, a primary heat exchange device and a drying box body; It is characterized in that The fan system includes a first fan and a second fan, which provide air flow power for the module; The temperature control system includes a first cooling device and a first heating device. The first cooling device is used to cool the air discharged by the first fan, and the first heating device is used to heat the air discharged by the second fan; It further includes a drying circulating air path, and the circulating air sequentially passes through the first fan, the first cooling device, the secondary heat exchange device, the treatment area of the dehumidification rotor, the primary heat exchange device, the second fan, the first heating device, the drying box body, the primary heat exchange device, and then enters the first fan to start circulating; It further includes a regeneration circulating air path, and the regeneration air sequentially passes through the first fan, the first cooling device, the secondary heat exchange device, the treatment area of the dehumidification rotor, the regeneration area of the dehumidification rotor, the primary heat exchange device, and then enters the first fan to start circulating; It further includes a second heating device, and the regeneration air passing through the treatment area of the dehumidification rotor is heated by the second heating device and then enters the regeneration area of the dehumidification rotor to perform desorption treatment on the dehumidification rotor; The secondary heat exchange device is an indirect evaporative cooling heat exchanger; the indirect evaporative cooling heat exchanger is further provided with a water distributor; The primary heat exchange device is a plate heat exchanger.

2. The high-efficiency heat exchange drying module according to claim 1, characterized in that: The temperature control system adopts a steam heating system.

3. The high-efficiency heat exchange drying module according to claim 2, wherein: The first cooling device is a cold water coil; the first heating device and the second heating device are both steam coils.

4. The high-efficiency heat exchange and drying module according to claim 1, wherein: The temperature control system adopts a heat pump system.

5. The high-efficiency heat exchange and drying module according to claim 4, wherein: The first cooling device is an evaporator; the first heating device and the second heating device are both condensers.

6. The high-efficiency heat exchange drying module according to claim 1, characterized in that: It further includes a filter; the circulating air discharged from the drying box body enters the filter for filtration and then enters the primary heat exchange device for heat exchange.

7. The high-efficiency heat exchange drying module according to claim 1, wherein: The circulating air after passing through the drying box body converges with the regeneration air passing through the regeneration area of the dehumidification rotor and then flows into the primary heat exchange device for heat exchange and cooling treatment.

8. A heat exchange and drying system, comprising production equipment and the efficient heat exchange and drying module according to any one of claims 1-7 connected to the production equipment.

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