Heat pump energy-saving device for paper production line
By designing a heat pump energy-saving device on the paper production line, heat in the condensate is recovered and steam is generated, solving the problem of unutilized condensate heat energy and achieving efficient energy utilization and environmental benefits.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- LUDONG UNIVERSITY
- Filing Date
- 2025-07-22
- Publication Date
- 2026-05-26
AI Technical Summary
In the paper industry, the heat energy contained in the condensate discharged from the paper production line is not fully utilized, resulting in energy waste and going against the development trend of energy conservation and environmental protection.
Design and construct a heat pump energy-saving device for a paper production line, including first and second heat pump units. The device recovers heat from the condensate through a flash tank and heat pump units, and uses the evaporator and condenser of the heat pump units for heat exchange to generate steam that can be used for production.
It significantly improves energy efficiency, reduces production costs, and decreases pollutant emissions, which aligns with energy conservation and emission reduction policies and promotes the green and sustainable development of the paper industry.
Smart Images
Figure CN224284989U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of energy conservation and environmental protection technology, specifically to a heat pump energy-saving device for a paper production line that utilizes condensate discharged from the paper production line to generate steam. Background Technology
[0002] In current papermaking production, steam, as an important heat source, is widely used in key processes such as paper setting and drying. Because papermaking production lines have high temperature requirements, the temperature of the residual steam condensate after completing the production process typically remains above 90°C. However, under traditional treatment methods, this condensate, carrying a large amount of heat energy, is often directly returned to the heat source plant, resulting in the inefficient utilization of its rich heat energy and energy waste, which is inconsistent with the current trend of energy conservation and environmental protection. Therefore, developing an energy-saving device that can efficiently recover and reuse the residual heat from the condensate discharged from papermaking production lines is of significant practical importance. Utility Model Content
[0003] The purpose of this invention is to design and build a heat pump energy-saving device for paper production lines that use steam as heat energy. This device is used to effectively recover and reuse the residual heat contained in the condensate discharged from the paper production line, thereby improving energy utilization efficiency, reducing production costs, and achieving energy conservation and emission reduction goals.
[0004] The solution adopted by this utility model to solve its technical problem is:
[0005] The heat pump energy-saving device for a paper production line, including a heat pump unit and a flash tank 10, is unique in that:
[0006] The heat pump unit includes a first heat pump unit and a second heat pump unit. The first heat pump unit includes a first evaporator 5, a first high-temperature compressor 2, a first condenser 8 and a first throttle 6 connected in series in a loop. The second heat pump unit includes a second evaporator 4, a second high-temperature compressor 3, a second condenser 9 and a second throttle 7 connected in series in a loop.
[0007] The first evaporator 5, the first high-temperature compressor 2, the first condenser 8, and the first throttle 6 of the first heat pump unit are all located outside the flash tank 10; the second condenser 9 of the second heat pump unit is located inside the flash tank 10, and the second evaporator 4, the second high-temperature compressor 3, and the second throttle 7 of the second heat pump unit are all located outside the flash tank 10.
[0008] The steam condensate discharge pipe 12 of the papermaking production line is connected to the water inlet of the flash tank 10 via a water pipe. The second evaporator 4 is connected to the flash tank 10 or the steam condensate discharge pipe 12 of the papermaking production line via a water pipe. The first evaporator 5 is connected to the second evaporator 4 via a water pipe. The bottom and top of the first condenser 8 are respectively connected to the bottom and top of the flash tank 10 via water pipes.
[0009] The steam outlet of flash tank 10 is connected to the steam supply pipeline of the paper production line.
[0010] Preferably, the steam outlet of the flash tank 10 is connected to the steam supply pipeline of the paper production line via the diversion jet pump 11.
[0011] Preferably, the second condenser 9 is located inside the flash tank 10 at a slightly higher position.
[0012] Preferably, the front end of the steam condensate discharge pipe 12 of the papermaking production line is also connected to a condensate collection unit for collecting the discharged high-temperature condensate.
[0013] Preferably, the condensate collection unit is equipped with a filter.
[0014] Preferably, a flow control valve is installed on the pipeline between the diversion jet pump 11 and the flash tank 10. The flow control valve is used to regulate the steam flow rate entering the diversion jet pump 11 from the flash tank 10.
[0015] Preferably, the outer surface of the second condenser 9 is provided with an anti-corrosion coating.
[0016] Preferably, the heat pump energy-saving device for the paper production line further includes a temperature sensor and a human-machine control unit. The temperature sensor is respectively installed in the steam condensate discharge pipeline 12, the flash tank 10 and the steam supply pipeline. The human-machine control unit is electrically connected to the temperature sensor, the first high-temperature compressor 2, the second high-temperature compressor 3, the first throttle 6 and the second throttle 7.
[0017] The principle of this invention is as follows: The paper production line discharges steam condensate at 90°C. The heat of the steam condensate is absorbed by the evaporator of the heat pump unit, and the condenser of the heat pump unit releases heat, causing the steam condensate to absorb heat and generate steam, which is then introduced to the steam supply end of the paper production line, thereby saving steam consumption.
[0018] The advantages of this utility model are:
[0019] (1) Significant energy saving effect: Through this energy saving device, a large amount of heat energy contained in the condensate discharged from the paper production line can be fully recovered and converted into steam for the production process again, which effectively reduces the demand of the paper production line for external energy, improves the comprehensive utilization efficiency of energy, and significantly saves energy consumption;
[0020] (2) Reduce production costs: Reduce the amount of external steam used, thus reducing the cost of steam procurement; at the same time, due to the improvement of energy utilization efficiency, the additional cost expenditure caused by energy waste is reduced, thereby reducing the overall operating cost of the paper production line and improving the economic benefits of the enterprise.
[0021] (3) Outstanding environmental benefits: The application of this device reduces pollutant emissions caused by energy waste, which meets the requirements of the national energy conservation and emission reduction policy, helps to promote the paper industry to develop in a green and sustainable direction, and has good social and environmental benefits;
[0022] (4) When the condensate from the production line passes through the flash tank and the two evaporators in sequence, the water temperature in the flash tank is high, which makes it easy to generate steam. The condensate remaining after the flash tank generates steam is used for the two evaporators to absorb heat. The condensate temperature in the second evaporator is high, so the temperature of the second condenser is also high. The condensate temperature in the first evaporator is low, so the temperature of the first condenser will also be low. This stepwise utilization of heat is more energy-efficient. Attached Figure Description
[0023] Figure 1 This is a schematic diagram illustrating the working principle of the present invention;
[0024] The components include: 1. Human-machine control unit; 2. First high-temperature compressor; 3. Second high-temperature compressor; 4. Second evaporator; 5. First evaporator; 6. First throttle; 7. Second throttle; 8. First condenser; 9. Second condenser; 10. Flash tank; 11. Diversion jet pump; 12. Steam condensate discharge pipeline. Detailed Implementation
[0025] The following is in conjunction with the appendix Figure 1 The present invention will be further illustrated by the embodiments.
[0026] like Figure 1 The present invention relates to a heat pump energy-saving device for a paper production line, comprising a heat pump unit and a flash tank 10, the specific structure of which is as follows:
[0027] The heat pump unit consists of a first heat pump unit and a second heat pump unit. The first heat pump unit is composed of a first evaporator 5, a first high-temperature compressor 2, a first condenser 8, and a first throttling device 6 connected in series in a loop; the second heat pump unit is composed of a second evaporator 4, a second high-temperature compressor 3, a second condenser 9, and a second throttling device 7 connected in series in a loop.
[0028] The first evaporator 5, the first high-temperature compressor 2, the first condenser 8, and the first throttle 6 of the first heat pump unit are all located outside the flash tank 10; the second condenser 9 of the second heat pump unit is located inside the flash tank 10, and the second evaporator 4, the second high-temperature compressor 3, and the second throttle 7 are located outside the flash tank 10.
[0029] The steam condensate discharge pipe 12 of the papermaking production line is connected to the water inlet of the flash tank 10 via a water pipe; the second evaporator 4 is connected to the flash tank 10 or the steam condensate discharge pipe 12 of the papermaking production line via a water pipe; the first evaporator 5 is connected to the second evaporator 4 via a water pipe; the bottom and top of the first condenser 8 are respectively connected to the bottom and top of the flash tank 10 via water pipes.
[0030] The steam outlet of the flash tank 10 is connected to the steam supply pipeline of the paper production line. It can be further connected to the steam supply pipeline of the paper production line through the diversion jet pump 11 to improve the steam delivery power and stability.
[0031] The second high-temperature compressor 3 and the first high-temperature compressor 2 are typically used under human-machine control in operating conditions where the evaporation temperature is between -140°C and 160°C.
[0032] Both the second evaporator 4 and the first evaporator 5 include condensate pipes and refrigerant pipes to ensure that the condensate and refrigerant can fully exchange heat.
[0033] The first condenser 8 is a fully enclosed plate heat exchanger with internal condensate and refrigerant piping to ensure sufficient heat exchange between the condensate and refrigerant.
[0034] The second condenser 9 can be either coiled or finned, and is equipped with refrigerant piping inside. The refrigerant piping exchanges heat with the liquid condensate or steam-water mixture in the flash tank.
[0035] The flash evaporator 10 utilizes the difference in saturated vapor pressure of substances at different temperatures to rapidly evaporate liquid substances by reducing the pressure, thereby achieving the conversion of liquid substances into gaseous substances. After absorbing heat, part of the liquid in the flash evaporator 10 flashes into steam, and the steam enters the steam supply pipeline of the papermaking production line through the diversion jet pump 11 to provide a heat source for the production process.
[0036] The diversion jet pump 11 is a pump with no moving parts designed based on the principle of fluid dynamics. It achieves fluid transport or mixing by transferring the kinetic energy generated by high-speed fluid. In this invention, the outlet of the flash tank 10 is connected to the low-pressure steam inlet of the diversion jet pump 11, and the low-pressure steam generated by the flash tank 10 is introduced into the steam supply end through the diversion jet pump 11.
[0037] The condensate from the 90°C steam discharged from the paper production line can flow sequentially to the flash tank 10, the second evaporator 4, and the first evaporator 5, or it can flow directly to the flash tank, bypass the flash tank 10, and then sequentially to the second evaporator 4 and the first evaporator 5. The condensate from the 90°C steam discharged from the paper production line flows to the flash tank 10, where it accumulates. Water exceeding the preset liquid level in the flash tank 10 flows to the condensate pipe in the first condenser 8. The condensate in the condensate pipe of the first condenser 8 absorbs heat from the refrigerant in the refrigerant pipe of the first condenser 8, generating steam. This steam is transported to the upper part of the flash tank 10, mixes with the steam inside the flash tank 10, and is then transported to the diversion jet pump 11. In the preferred production line, the condensate flows sequentially through a flash tank and two evaporators. With this connection, the water temperature in the flash tank is high, making it easy to generate steam. The condensate remaining after the steam is generated in the flash tank is used for heat absorption in the two evaporators. The condensate temperature in the second evaporator is high, so the temperature of the second condenser is also high. The condensate temperature in the first evaporator is low, so the temperature of the first condenser is also low. This stepwise utilization of heat makes it more energy-efficient.
[0038] The condensate from the 90°C steam discharged from the paper production line exchanges heat with the first evaporator 5 of the first heat pump unit and the second evaporator 4 of the second heat pump unit. The refrigerant in the first evaporator 5 and the second evaporator 4 is heated and further compressed and heated by the first high-temperature compressor 2 and the second high-temperature compressor 3. It then reaches the first condenser 8 and the second condenser 9 to release heat, causing steam to be generated in the condensate pipe of the first condenser 8. The heat released by the second condenser 9 causes the condensate from the steam, which was originally close to 90°C, in the flash tank 10 to absorb less heat and generate steam. The refrigerant after releasing heat in the first condenser 8 and the second condenser 9 is throttled and depressurized by the first throttling device 6 and the second throttling device 7, respectively, and then returns to the first evaporator 5 and the second evaporator 4, completing one heat pump cycle.
[0039] Preferred, such as Figure 1 As shown, when the first evaporator 5 receives condensate from the second evaporator 4, the heat of the condensate has already been absorbed and utilized by the flash tank 10 and the second evaporator 4. Therefore, an auxiliary heating device is provided at the first condenser 8 to assist the first condenser 8 in generating steam.
[0040] Preferably, based on the principle that hot air rises and cold air falls, the second condenser 9 is located inside the flash tank 10 and slightly above it, which facilitates sufficient heat exchange between the steam and the condenser, and also makes it easier for the steam to be discharged from the top of the flash tank. Since the condensate in the flash tank 10 comes directly from the production line and has a high temperature, only a small amount of heat from the second condenser 9 is needed to generate steam.
[0041] Preferably, the steam condensate discharge pipe 12 of the papermaking production line is connected to a condensate collection unit at its front end. The condensate collection unit is located at various points in the papermaking production line where condensate is generated, such as below the drying cylinder. The condensate collection unit is equipped with a filter to remove impurities from the condensate, preventing damage to downstream equipment. After the papermaking production line is started, steam undergoes heat exchange during production, forming condensate. This condensate is filtered by the condensate collection unit and then enters the steam condensate discharge pipe 12, before flowing into the flash tank 10.
[0042] Preferably, the flash tank 10 is equipped with a liquid level sensor to monitor the liquid level of the condensate in real time and transmit the liquid level information to the human-machine control unit.
[0043] Preferably, a flow control valve is installed on the pipeline between the diversion jet pump 11 and the flash tank 10 to adjust the steam flow rate entering the diversion jet pump 11 from the flash tank 10, so as to adapt to the different steam requirements of the production line.
[0044] Preferably, since the second condenser 9 is located inside the flash tank 10 and is in a gas-liquid mixing or high-temperature liquid environment, an anti-corrosion coating is provided on the outer surface of the second condenser 9 to extend the service life of the second condenser 9 and adapt to the condensate environment.
[0045] Preferably, the heat pump energy-saving device for the paper production line also includes a human-machine control unit and several temperature sensors. The temperature sensors are respectively installed in the steam condensate discharge pipe 12, the two evaporators, the two condensers, the flash tank 10, and the steam supply pipe. The human-machine control unit is electrically connected to the temperature sensors, the first high-temperature compressor 2, the second high-temperature compressor 3, the first throttle 6, and the second throttle 7. It adjusts the compressor operating power and the throttle parameters based on the temperature data detected by the temperature sensors. The human-machine control unit facilitates operator monitoring and parameter setting.
Claims
1. A heat pump energy-saving device for a paper production line, comprising a heat pump unit and a flash tank (10), characterized in that: The heat pump unit includes a first heat pump unit and a second heat pump unit. The first heat pump unit includes a first evaporator (5), a first high-temperature compressor (2), a first condenser (8) and a first throttle (6) connected in series. The second heat pump unit includes a second evaporator (4), a second high-temperature compressor (3), a second condenser (9) and a second throttle (7) connected in series. The first evaporator (5), the first high-temperature compressor (2), the first condenser (8) and the first throttle (6) of the first heat pump unit are all located outside the flash tank (10); the second condenser (9) of the second heat pump unit is located inside the flash tank (10), and the second evaporator (4), the second high-temperature compressor (3) and the second throttle (7) of the second heat pump unit are all located outside the flash tank (10); The steam condensate discharge pipe (12) of the paper production line is connected to the water inlet of the flash tank (10) through a water pipe. The second evaporator (4) is connected to the flash tank (10) or the steam condensate discharge pipe (12) of the paper production line through a water pipe. The first evaporator (5) is connected to the second evaporator (4) through a water pipe. The bottom and top of the first condenser (8) are connected to the bottom and top of the flash tank (10) through water pipes, respectively. The steam outlet of the flash tank (10) is connected to the steam supply pipeline of the paper production line.
2. The heat pump energy-saving device for a paper production line according to claim 1, characterized in that: The steam outlet of the flash tank (10) is connected to the steam supply pipeline of the paper production line via a diversion jet pump (11).
3. The heat pump energy-saving device for a papermaking production line according to claim 1 or 2, characterized in that: The second condenser (9) is located inside the flash tank (10) at a slightly higher position.
4. The heat pump energy-saving device for a paper production line according to claim 3, characterized in that: The front end of the steam condensate discharge pipeline (12) of the paper production line is also connected to a condensate collection unit for collecting the discharged high-temperature condensate.
5. The heat pump energy-saving device for a paper production line according to claim 4, characterized in that: The condensate collection unit is equipped with a filter.
6. The heat pump energy-saving device for a paper production line according to claim 5, characterized in that: A flow control valve is installed on the pipeline between the diversion jet pump (11) and the flash tank (10).
7. The heat pump energy-saving device for a papermaking production line according to claim 6, characterized in that: The outer surface of the second condenser (9) is provided with an anti-corrosion coating.
8. The heat pump energy-saving device for a paper production line according to claim 7, characterized in that: The heat pump energy-saving device for the paper production line also includes a temperature sensor and a human-machine control unit. The temperature sensor is respectively installed in the steam condensate discharge pipeline (12), the flash tank (10) and the steam supply pipeline. The human-machine control unit is electrically connected to the temperature sensor, the first high-temperature compressor (2), the second high-temperature compressor (3), the first throttle (6) and the second throttle (7).