Drying tower exhaust waste heat recycling system utilizing loop heat pipe

Abstract

The utility model discloses a drying tower exhaust air waste heat recycling system utilizing a loop heat pipe, which belongs to the technical field of energy conservation and emission reduction, and comprises an air inlet module, a steam heating module, a drying module and an air exhaust module which are sequentially connected, and a waste heat recycling and preheating module is arranged between the air inlet module and the air exhaust module. A main body of the waste heat recovery preheating module is composed of a plurality of parallel and independent loop heat pipes, the heat pipe condensation ends of the loop heat pipes are arranged in the air inlet module, and the heat pipe evaporation ends of the loop heat pipes are arranged in the air exhaust module. The loop heat pipe between the heat pipe condensation end and the heat pipe evaporation end is a steam loop and a condensation loop. According to the drying tower exhaust waste heat recycling system utilizing the loop heat pipe, fresh air is preheated through the waste heat recycling and preheating module, fuel consumption can be greatly reduced, an extra circulating pump is not needed to drive a working medium to circulate, and energy consumption can be further reduced.

Description

Technical Field

[0001] This utility model relates to the field of energy conservation and emission reduction technology, and in particular to a system for recovering and utilizing waste heat from the exhaust of a drying tower using a loop heat pipe. Background Technology

[0002] Heat pipe technology fully utilizes the principles of heat conduction and the rapid heat transfer properties of phase change media. It rapidly transfers heat from a heat-generating object to the outside of the heat source, with a thermal conductivity exceeding that of any known metal. A loop heat pipe is a closed-loop annular heat pipe, typically composed of an evaporator, condenser, receiver, and corresponding piping. Its working process is as follows: the working fluid, under thermal load, evaporates on the outer surface of the evaporator capillary wick. The resulting vapor flows out of the vapor channel and into the vapor line, then enters the condenser, condenses into liquid, and is subcooled. The returning liquid flows through the liquid line into the liquid main to replenish the evaporator capillary wick, thus completing the cycle. The driving force for the circulation of the working fluid is the capillary pressure generated by the evaporator capillary wick, requiring no external power. Because the condensation and evaporation sections are separate, loop heat pipes are widely used in comprehensive energy utilization and waste heat recovery.

[0003] The fresh air heating system of a drying tower in the dairy industry typically includes a two-stage heating process: steam preheating and steam heating. First, high-temperature steam from a steam boiler is used to preheat the air in an air preheater. Then, a steam heater heats the preheated air to the drying temperature before it is fed into the drying tower. After passing through the production process, the air temperature gradually decreases and, after dust removal and other processes, is released into the atmosphere at an exhaust temperature of approximately 90°C. This heat is low-grade thermal energy, making waste heat recovery methods such as waste heat boilers and organic Rankine cycles difficult. On the other hand, due to the large volume of exhaust air, it contains significant potential for waste heat recovery. Directly releasing it into the atmosphere would result in heat waste and thermal pollution. Therefore, it is necessary to recover and utilize this large quantity of low-grade exhaust waste heat to achieve energy conservation and emission reduction. Summary of the Invention

[0004] The purpose of this invention is to provide a waste heat recovery system for the exhaust air of a drying tower that utilizes a loop heat pipe. By using the waste heat to preheat the fresh air, fuel can be greatly saved, and no additional circulating pump is required to drive the working fluid circulation, which can further reduce energy consumption.

[0005] To achieve the above objectives, this utility model provides a waste heat recovery and utilization system for the exhaust of a drying tower using loop heat pipes. The system includes an air inlet module, a steam heating module, a drying module, and an exhaust module connected in sequence. A waste heat recovery preheating module is installed between the air inlet module and the exhaust module. The main body of the waste heat recovery preheating module consists of several parallel, independent loop heat pipes. The condensing end of each loop heat pipe is located within the air inlet module, and the evaporating end of each loop heat pipe is located within the exhaust module. The loop heat pipes between the condensing and evaporating ends of the heat pipes are respectively a steam circuit and a condensation circuit.

[0006] Preferably, the air intake module includes an air intake chamber, and the air outlet of the air intake chamber is connected to a first induced draft fan.

[0007] Preferably, the first induced draft fan is connected to the blower located at the air inlet of the steam heating module.

[0008] Preferably, a filter is installed on the air inlet side of the first induced draft fan.

[0009] Preferably, the filtration device includes a dust removal component, a sterilization mesh, and an activated carbon mesh.

[0010] Preferably, the exhaust module includes an exhaust duct, and a second exhaust fan is provided at the air outlet of the exhaust duct.

[0011] Preferably, both the air inlet chamber and the air outlet duct are provided with fins that are respectively connected to the condenser end and the evaporator end of the heat pipe.

[0012] Preferably, the drying module includes a drying tower, and a cyclone separator is connected to the air outlet side of the drying tower.

[0013] Preferably, the steam heating module includes a steam boiler and a main heater, and the steam generated by the steam boiler is sent to the main heater through a steam pipe for heat exchange.

[0014] Preferably, the steam boiler is a gas-fired boiler.

[0015] Therefore, the beneficial effects of this utility model using the above-mentioned waste heat recovery and utilization system for drying tower exhaust using a loop heat pipe are as follows:

[0016] (1) This invention utilizes the waste heat of exhaust air to preheat fresh air. After the fresh air is preheated by exhaust air, its temperature is increased, which replaces the steam preheater, saving the steam consumption in the fresh air heating process and the fuel consumption of the boiler, thus achieving the effect of energy saving and emission reduction.

[0017] (2) The exhaust air of the present invention is discharged into the atmosphere after waste heat recovery and utilization, which reduces thermal pollution to the environment.

[0018] (3) The present invention saves a lot of fuel consumption and reduces operating costs while ensuring the drying effect.

[0019] (4) The present invention replaces the steam preheating system, reduces the complexity and accident rate of the fresh air heating system, and improves the stability of system operation.

[0020] (5) The present invention uses a loop heat pipe as an intermediate loop, which makes full use of the heat conduction principle and the rapid heat transfer properties of the phase change medium. Since the driving force of the heat pipe is capillary pressure, the loop does not need to consume additional energy.

[0021] (6) The present invention uses multiple loop heat pipes to operate independently in parallel. The failure of a single heat pipe has almost no impact on the waste heat recovery system and can be replaced individually, ensuring the stable operation of the entire system.

[0022] (7) The present invention directly arranges the evaporation end of the loop heat pipe in the exhaust duct and the condensation end in the air inlet chamber, without requiring much modification to the original piping system.

[0023] (8) The present invention reduces the exhaust temperature by recovering waste heat, thereby reducing the working temperature of the exhaust fan and improving the reliability of the equipment.

[0024] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of an embodiment of a drying tower exhaust waste heat recovery and utilization system utilizing loop heat pipes according to this utility model;

[0026] Figure 2 This is a cross-sectional schematic diagram of the waste heat recovery preheating module of an embodiment of a waste heat recovery and utilization system for exhaust air of a drying tower using a loop heat pipe according to this utility model.

[0027] Figure Labels

[0028] 1. Heat pipe condenser end; 2. Air inlet chamber; 3. Filtration equipment; 4. First induced draft fan; 5. Steam boiler; 6. Exhaust fan; 7. Main heater; 8. Drying tower; 9. Cyclone separator; 10. Heat pipe evaporator end; 11. Exhaust duct; 12. Fins; 13. Second induced draft fan; 14. Steam circuit; 15. Condensation circuit. Detailed Implementation

[0029] The technical solution of this utility model will be further described below with reference to the accompanying drawings and embodiments.

[0030] Unless otherwise defined, the technical or scientific terms used in this utility model shall have the ordinary meaning understood by one of ordinary skill in the art to which this utility model pertains. The terms "first," "second," and similar terms used in this utility model do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0031] Example 1

[0032] like Figure 1 As shown, this utility model provides a waste heat recovery and utilization system for the exhaust of a drying tower using a loop heat pipe, including an air inlet module, a steam heating module, a drying tower 8 and an exhaust module connected in sequence, with a waste heat recovery preheating module installed between the air inlet module and the exhaust module.

[0033] The air intake module includes an air intake chamber 2, with a first induced draft fan 4 connected to the air outlet of the air intake chamber 2 for drawing fresh air from the atmosphere. A filter device 3 is installed on the air intake side of the first induced draft fan 4. The filter device 3 includes a dust removal component, a sterilization screen, and an activated carbon screen, which respectively remove dust, sterilize, and absorb harmful gases from the fresh air. The first induced draft fan 4 is connected to a blower fan 6 located at the air inlet of the steam heating module for blowing air into the steam heating module.

[0034] The steam heating module includes a steam boiler 5 and a main heater 7. In this embodiment, the steam boiler 5 is a gas-fired boiler. The high-temperature steam generated by the steam boiler 5 is sent to the main heater 7 through a steam pipe for heat exchange, further heating the fresh air to the drying temperature.

[0035] The drying module includes a drying tower 8, with a cyclone separator 9 connected to the air outlet side of the drying tower 8 to facilitate the separation of moisture. The exhaust module includes an exhaust duct 11 connected to the cyclone separator 9, with a second induced draft fan 13 installed at the air outlet of the exhaust duct 11 to ensure smooth air discharge.

[0036] The main body of the waste heat recovery preheating module consists of several parallel, independent loop heat pipes. The condensing end 1 of the loop heat pipes is located in the air inlet chamber 2 of the air inlet module, and the evaporating end 10 of the loop heat pipes is located in the exhaust duct 11 of the exhaust module. The loop heat pipes between the condensing end 1 and the evaporating end 10 are respectively a steam circuit 14 and a condensing circuit 15. Fins 12, respectively connected to the condensing end 1 and the evaporating end 10 of the heat pipes, are installed in both the air inlet chamber 2 and the exhaust duct 11. Figure 2 As shown, this facilitates increasing the heat exchange area, thereby improving heat exchange efficiency.

[0037] When the working fluid inside the heat pipe evaporator 10 receives a heat load, it undergoes a phase change and generates steam. The generated steam flows into the heat pipe condenser 1 through the steam circuit 14 under the action of capillary force. The working fluid in the heat pipe condenser 1 transfers heat to the fresh air, the temperature of the working fluid drops and it condenses into liquid, and flows into the heat pipe evaporator 10 through the condenser circuit 15 for replenishment. This cycle repeats, achieving the effect of active heat exchange.

[0038] The following compares the use of exhaust waste heat to preheat fresh air with the use of a solution not described in this embodiment:

[0039] Based on the system's energy conservation principle, when the exhaust volume is 100,000 kg / h and the ambient temperature is -20℃, the fresh air temperature can be preheated to 48℃, while the exhaust air temperature drops to 20℃. Using a waste heat recovery system can save 4.1 t / h of steam. Taking the SZS35-2.5-Y,Q model gas boiler as an example, this can save 290 Nm³ of steam. 3 The waste heat recovery preheating module in this embodiment achieves good economic benefits by reducing the gas consumption by a certain amount per hour.

[0040] Therefore, this utility model adopts the aforementioned waste heat recovery system for drying tower exhaust using a loop heat pipe. The loop heat pipe serves as an intermediate loop to recover and utilize the waste heat from the drying tower exhaust to preheat the fresh air drawn from the atmosphere. This replaces the traditional steam preheating system, which preheats the fresh air to a certain temperature before sending it to the steam heating module for further heating. Based on the excellent heat transfer performance of the loop heat pipe, the waste heat from the exhaust is effectively recovered and utilized, significantly reducing the steam and fuel consumption of the steam heating module. Furthermore, since the loop heat pipe serves as the intermediate loop, and the driving force of the loop is capillary force, no additional energy consumption is added, resulting in greater energy savings.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although the utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solution of this utility model, and these modifications or equivalent substitutions cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of this utility model.

Claims

1. A drying tower exhaust heat recovery system using a loop heat pipe, characterized by: The device comprises sequentially connected air inlet module, steam heating module, drying module and air exhaust module, a waste heat recovery preheating module is installed between the air inlet module and the air exhaust module, the main body of the waste heat recovery preheating module is a plurality of parallel and independent loop heat pipes, the heat pipe condensing end of the loop heat pipe is arranged in the air inlet module, the heat pipe evaporation end of the loop heat pipe is arranged in the air exhaust module, and the loop heat pipe between the heat pipe condensing end and the heat pipe evaporation end is respectively a steam loop and a condensation loop.

2. The exhaust heat recovery system of a drying tower using a loop heat pipe according to claim 1, characterized in that: The air inlet module comprises an air inlet chamber, and a first air induction fan is connected to the air outlet end of the air inlet chamber.

3. The exhaust heat recovery system of a drying tower using a loop heat pipe according to claim 2, characterized in that: The first air induction fan is connected to an air supply fan located at the air inlet of the steam heating module.

4. The exhaust heat recovery system of a drying tower using a loop heat pipe according to claim 2, characterized in that: A filtering device is installed on the air inlet side of the first air induction fan.

5. The exhaust heat recovery system of a drying tower using a loop heat pipe according to claim 4, wherein: The filtering device comprises a dust removal assembly, a sterilization net and an activated carbon net.

6. The exhaust heat recovery system of a drying tower using a loop heat pipe according to claim 2, characterized in that: The air exhaust module comprises an air exhaust pipeline, and a second air induction fan is arranged at the air outlet of the air exhaust pipeline.

7. The exhaust heat recovery system of a drying tower using a loop heat pipe according to claim 6, characterized in that: Fins are arranged in the air inlet chamber and the air exhaust pipeline and connected to the heat pipe condensing end and the heat pipe evaporation end respectively.

8. The exhaust heat recovery system of a drying tower using a loop heat pipe according to claim 1, characterized in that: The drying module comprises a drying tower, and a cyclone separator is connected to the air outlet side of the drying tower.

9. The exhaust heat recovery system of a drying tower using a loop heat pipe according to claim 1, characterized in that: The steam heating module comprises a steam boiler and a main heater, steam generated by the steam boiler is sent to the main heater through a steam pipeline for heat exchange.

10. The exhaust heat recovery system of a drying tower using a loop heat pipe according to claim 9, wherein: The steam boiler is a gas-fired boiler.

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