Waste heat recovery processing device, vacuum system applied by waste heat recovery processing device and recovery processing method

Abstract

The invention relates to the field of waste heat recovery, and discloses a waste heat recovery processing device, a vacuum system applying the waste heat recovery processing device and a recovery processing method.The waste heat recovery processing device comprises a container, a first circulating pump, a reversing valve, a first heat exchange pipeline, a second heat exchange pipeline, a waste heat recovery pipeline, a circulating heat supply pipeline and a temperature sensor; heat transfer is conducted between the first heat exchange section and the fourth heat exchange section in a heat exchange mode, circulating liquid which is subjected to heat exchange and temperature rise in the fourth heat exchange section is used for supplying heat in the fifth heat exchange section, and real-time adjustment of the opening degree of the reversing valve is achieved based on the temperature of the circulating liquid in a fourth liquid supply pipe and electric linkage between a temperature sensor and the reversing valve. And the heat exchange power between the first heat exchange section and the fourth heat exchange section is kept stable, so that the heat supply power of the fifth heat exchange section is kept stable.

Description

Technical Field

[0001] The present invention relates to the field of waste heat recovery, and in particular to a waste heat recovery and treatment device and a vacuum system and a recovery and treatment method applied thereto. Background Art

[0002] In industrial production, the efficient operation of various types of mechanical equipment is crucial to ensuring a smooth production process. However, this equipment inevitably generates significant amounts of heat during operation. For example, in cigarette manufacturing, the rolling and packaging workshop's equipment, such as the packaging and packaging units and automatic packaging machines, has extremely high vacuum pressure requirements, with stringent requirements for both vacuum level and negative pressure stability. This high-load operating demand forces the vacuum systems used in these workshops to operate at high intensity for extended periods, causing the vacuum pumps to generate significant heat during operation. If this excess heat is not removed promptly and effectively, it not only reduces the efficiency of the vacuum pump and the entire vacuum system, but can also cause equipment failure, disrupting the normal operation of cigarette production.

[0003] While existing technologies have employed waste heat recovery devices to recycle and reuse this excess heat, practical applications still present challenges. Some heat-using equipment has certain temperature requirements for recovered heat. Large temperature fluctuations or a persistent rise in the recovered heat temperature can adversely affect the normal operation of the equipment, even causing damage and reducing the stability and reliability of the entire production system. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problem that the existing waste heat recovery device cannot output stable heat for heating when the recovered heat has large temperature fluctuations or is in a continuously rising state, and to provide a waste heat recovery processing device that can output stable heat for heating.

[0005] In order to achieve the above object, the present invention provides a waste heat recovery and processing device, comprising: a container containing a working fluid; a first circulation pump, wherein a liquid inlet of the first circulation pump is in communication with the interior of the container; a reversing valve, wherein the liquid inlet of the reversing valve is connected to the liquid outlet of the first circulating pump; a first heat exchange pipeline, the first heat exchange pipeline comprising a first liquid supply pipe, a first heat exchange section, and a first liquid return pipe, which are sequentially connected along the flow direction of the working fluid, the first liquid supply pipe being connected to one of the liquid outlets of the reversing valve, and the first liquid return pipe being connected to the container at an end away from the first heat exchange section; a second heat exchange pipeline, the second heat exchange pipeline comprising a second liquid supply pipe, a second heat exchange section, and a second liquid return pipe, which are sequentially connected along the flow direction of the working fluid, the second liquid supply pipe being connected to the other liquid outlet of the reversing valve, and the second liquid return pipe being connected to the container at one end away from the second heat exchange section; a waste heat recovery pipeline, the waste heat recovery pipeline comprising a third liquid supply pipe, a third heat exchange section, and a third liquid return pipe sequentially connected along the flow direction of the working fluid, the third liquid supply pipe and the third liquid return pipe being connected to the container at one end away from the third heat exchange section; a circulating heat supply pipeline, the circulating heat supply pipeline comprising a fourth heat exchange section, a fourth liquid supply pipe, a fifth heat exchange section, and a fourth liquid return pipe connected end to end in sequence, the fourth heat exchange section exchanging heat with the first heat exchange section; A temperature sensor is used to monitor the temperature of the circulating liquid in the fourth liquid supply pipe, and the temperature sensor is electrically connected to the reversing valve.

[0006] In some embodiments, a driving pump for driving the flow of working fluid or circulating fluid is provided in the waste heat recovery pipeline and / or the circulating heating pipeline.

[0007] A second aspect of the present invention provides a vacuum system using the waste heat recovery and treatment device described above, the vacuum system further comprising a vacuum pump and a vacuum tank, wherein the inlet end of the vacuum pump is connected to the interior of the vacuum tank via a connecting pipe; Wherein, the third heat exchange section in the waste heat recovery and treatment device is used for heat exchange and absorption of waste heat generated during the operation of the vacuum pump.

[0008] In some embodiments, when the vacuum pump uses liquid as the working medium, the working liquid supply end and the outlet end of the vacuum pump are connected to the third heat exchange section along the flow direction of the working liquid.

[0009] In some embodiments, a cavitation protection pipeline is connected between the container and the interior of the vacuum pump.

[0010] In some embodiments, the container adopts an air-water separator, and the air-water separator is provided with a water supply port, a water discharge port, an overflow port and an air exhaust port.

[0011] In some embodiments, when the vacuum pump uses gas as a working medium, the third heat exchange section exchanges heat with the gas discharged from the vacuum pump.

[0012] In some embodiments, there are multiple vacuum pumps arranged in parallel.

[0013] In some embodiments, when the pressure in the vacuum tank is lower than a set lower limit pressure and all the vacuum pumps in operation are running at full frequency, the number of the vacuum pumps in operation is increased; When the pressure in the vacuum tank is higher than the set upper limit pressure, and all the vacuum pumps put into operation are operating at the lowest frequency, and the number of the vacuum pumps put into operation is at least two, the number of the vacuum pumps put into operation is reduced.

[0014] A third aspect of the present invention provides a waste heat recovery method using the waste heat recovery device described above, comprising the following steps: obtaining the temperature of the circulating fluid in the fourth fluid supply pipe; If the circulating fluid temperature meets the heat demand temperature of the heat-consuming equipment, the reversing valve is kept connected to only the first liquid supply section; If the temperature of the circulating fluid is higher than the heat demand temperature of the heat-consuming equipment, the opening of the reversing valve connected to the first liquid supply section is reduced and the opening of the reversing valve connected to the second liquid supply section is increased; If the circulating fluid temperature is lower than the heat demand temperature of the heat-consuming equipment, the reversing valve is kept connected to only the second liquid supply section.

[0015] The waste heat recovery device using the above technical solution of the present invention has the following effects: Heat is transferred between the first heat exchange section and the fourth heat exchange section by heat exchange. The circulating fluid heated by heat exchange in the fourth heat exchange section is used for heat supply in the fifth heat exchange section. The opening of the reversing valve is adjusted in real time based on the temperature of the circulating fluid in the fourth liquid supply pipe and the electrical linkage between the temperature sensor and the reversing valve, so that the heat exchange power between the first heat exchange section and the fourth heat exchange section remains stable, thereby keeping the power used for heating in the fifth heat exchange section stable.

[0016] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a waste heat recovery and treatment device according to one embodiment of the present invention; Figure 2 It is a structural diagram of a waste heat recovery and treatment device equipped with a plate heat exchanger and a cooling tower; Figure 3 This is a structural diagram of a vacuum system using a waste heat recovery device according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the cavitation protection pipeline configured in the vacuum system; Figure 5 This is a schematic diagram of the structure of a vacuum pump using liquid as the working medium; Figure 6 It is a structural diagram of a container using an air-water separator; Figure 7 This is a schematic diagram of the structure of a vacuum pump using gas as the working medium and the third heat exchange section facing each other; Figure 8 This is a schematic diagram of a vacuum system structure in which multiple vacuum pumps are connected in parallel according to an embodiment of the present invention; Figure 9 This is a schematic diagram of the vacuum system structure with multiple vacuum pumps configured in parallel and equipped with cavitation protection pipelines.

[0018] Description of Reference Numerals 1. Container; 1a. Water supply port; 1b. Drain port; 1c. Overflow port; 1d. Exhaust port; 2. First circulation pump; 3. Reversing valve; 4. First heat exchange pipeline; 4a. First liquid supply pipe; 4b. First heat exchange section; 4c. First liquid return pipe; 5. Second heat exchange pipeline; 5a. Second liquid supply pipe; 5b. Second heat exchange section; 5c. Second liquid return pipe; 6. Waste heat recovery pipeline; 6a. Third liquid supply pipe; 6b. Third heat exchange section; 6c. Third liquid return pipe; 7. Circulating supply pipe Heat pipe; 7a, fourth heat exchange section; 7b, fourth liquid supply pipe; 7c, fifth heat exchange section; 7d, fourth liquid return pipe; 8, temperature sensor; 9, drive pump; 10, vacuum pump; 10a, supply end; 10b, outlet end; 10c, inlet end; 10d, cavitation protection port; 11, vacuum tank; 12, connecting pipe; 13, cavitation protection pipe; 14, vacuum pressure gauge; 15, sewage outlet; 16, heat-using equipment; 17, plate heat exchanger; 18, cooling tower. DETAILED DESCRIPTION

[0019] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0020] In the first aspect of the present invention, a waste heat recovery device is provided, as shown in the attached Figure 1 As shown, the waste heat recovery device includes a container 1, a first circulating pump 2, a reversing valve 3, a first heat exchange pipeline 4, a second heat exchange pipeline 5, a waste heat recovery pipeline 6, a circulating heat supply pipeline 7, and a temperature sensor 8. The waste heat recovery device can absorb excess heat generated by the heating equipment and stably output the absorbed excess heat for heating reuse.

[0021] Container 1 contains a working fluid, typically water. The inlet of a first circulating pump 2 is connected to the interior of container 1 and is used to pump the working fluid from container 1. To ensure a stable flow of the working fluid pumped by first circulating pump 2, the inlet of first circulating pump 2 is located at the bottom of container 1.

[0022] The inlet of reversing valve 3 is connected to the outlet of first circulating pump 2. The working fluid flow stream drawn by first circulating pump 2 first flows through reversing valve 3 and then flows out through the outlet of reversing valve 3. Reversing valve 3 generally has two or more outlets. The opening and closing of these outlets and the degree of opening are adjusted by adjusting the position of the valve core inside reversing valve 3, thereby adjusting the flow direction and flow rate of the working fluid flow stream through reversing valve 3. A reversing valve 3 with an appropriate number of outlets can be selected based on actual needs.

[0023] The first heat exchange pipeline 4 includes a first liquid supply pipe 4a, a first heat exchange section 4b, and a first liquid return pipe 4c, which are sequentially connected along the flow direction of the working fluid. The first liquid supply pipe 4a is connected to one of the liquid outlets of the reversing valve 3, and the first liquid return pipe 4c is connected to the container 1 at its end away from the first heat exchange section 4b. The second heat exchange pipeline 5 includes a second liquid supply pipe 5a, a second heat exchange section 5b, and a second liquid return pipe 5c, which are sequentially connected along the flow direction of the working fluid. The second liquid supply pipe 5a is connected to the other liquid outlet of the reversing valve 3, and the second liquid return pipe 5c is connected to the container 1 at its end away from the second heat exchange section 5b. The working fluid flowing in the first heat exchange pipeline 4 supplies heat to the outside in the first heat exchange section 4b. Similarly, the working fluid flowing in the second heat exchange pipeline 5 supplies heat to the outside in the second heat exchange section 5b.

[0024] In the present invention, two working fluid flow paths are located downstream of the reversing valve 3: the first heat exchange pipeline 4 and the second heat exchange pipeline 5. Therefore, a three-way reversing valve (i.e., one inlet and two outlets) can be used. The first liquid supply pipe 4a connects to one outlet of the reversing valve 3, while the second liquid supply pipe 5a connects to the other outlet of the reversing valve 3. Of course, a reversing valve 3 with more than two outlets can also meet operational requirements; the outlet not connected to the first heat exchange pipeline 4 or the second heat exchange pipeline 5 need only be normally closed during use.

[0025] In addition, the first liquid return pipe 4c and the second liquid return pipe 5c are both working fluid return pipes. To facilitate the reflux of the working fluid and prevent backflow, the connection parts of the first liquid return pipe 4c, the second liquid return pipe 5c and the container 1 are both at the top of the container 1 or near the top of the container 1.

[0026] The waste heat recovery pipeline 6 includes a third liquid supply pipe 6a, a third heat exchange section 6b, and a third liquid return pipe 6c, which are sequentially connected along the flow direction of the working fluid. The third liquid supply pipe 6a and the third liquid return pipe 6c are both connected to the container 1 at their ends away from the third heat exchange section 6b. The working fluid circulating in the container 1 and the waste heat recovery pipeline 6 recovers excess heat in the third heat exchange section 6b, ultimately raising the temperature of the working fluid inside the container 1 and storing the excess heat in the working fluid inside the container 1. The high-temperature working fluid can then be supplied to the first heat exchange pipeline 4 and the second heat exchange pipeline 5 via the first circulation pump 2 and the reversing valve 3, and the high-temperature working fluid is then exchanged outward at the first heat exchange section 4b and the second heat exchange section 5b to achieve the purpose of heating.

[0027] Similarly, to facilitate the flow of working fluid in the waste heat recovery pipeline 6 and prevent backflow, the connection between the third liquid supply pipe 6a and the container 1 is at the bottom of the container 1, and the connection between the third liquid return pipe 6c and the container 1 is at the top of the container 1 or near the top.

[0028] It should be noted that in the attached Figure 1 In the figures and other drawings, the third liquid supply pipe 6a is shown in a disconnected form to avoid intersection with the second liquid return pipe 5c as shown in the figure.

[0029] The circulating heat supply pipeline 7 includes a fourth heat exchange section 7a, a fourth liquid supply pipe 7b, a fifth heat exchange section 7c, and a fourth liquid return pipe 7d, which are connected end to end. Both the fourth heat exchange section 7a and the fifth heat exchange section 7c are capable of heat exchange. Specifically, the fourth heat exchange section 7a exchanges heat with the first heat exchange section 4b, while the fifth heat exchange section 7c exchanges heat externally to supply heat to the heat-consuming device 16.

[0030] The heat of the working fluid circulating in the first heat exchange pipeline 4 comes from the surplus heat in the production process. The surplus heat in the production process has large temperature fluctuations, or long-term production will cause the surplus heat to be continuously output, which ultimately causes the working fluid temperature circulating in the first heat exchange pipeline 4 to fluctuate greatly or the working fluid temperature to continue to rise. If the working fluid in the first heat exchange pipeline 4 is directly output to the outside to supply heat to the heat-consuming equipment 16, it often cannot meet the heat demand temperature of the heat-consuming equipment 16. After heat exchange between the first heat exchange section 4b and the fourth heat exchange section 7a, the heat of the working fluid in the first heat exchange pipeline 4 is transferred to the circulating fluid in the fourth heat exchange section 7a, and then the heat is output to the outside through the fifth heat exchange section 7c in the circulating heat supply pipeline 7 to supply heat to the heat-consuming equipment 16. This increases the heat exchange effect between the first heat exchange section 4b and the fourth heat exchange section 7a, reduces the impact of working fluid temperature fluctuations on the circulating fluid heating temperature at the fifth heat exchange section 7c, and improves the stability of the heating temperature at the fifth heat exchange section 7c.

[0031] In addition, a temperature sensor 8 is configured to monitor the temperature of the circulating fluid in the fourth liquid supply pipe 7b and is electrically connected to the reversing valve 3. The outlet opening and on / off adjustment of the reversing valve 3 are controlled based on the circulating fluid temperature in the fourth liquid supply pipe 7b to ensure stable heat exchange power between the first heat exchange section 4b and the fourth heat exchange section 7a.

[0032] Specifically, when the working fluid temperature in the first heat exchange pipeline 4 continues to rise, if the working fluid flow rate in the first heat exchange pipeline 4 remains unchanged, the heat exchange power between the first heat exchange section 4b and the fourth heat exchange section 7a will increase, eventually causing the circulating fluid temperature in the circulating heat supply pipeline 7 to rise, and the working fluid temperature at the fifth heat exchange section 7c is higher than the heat demand temperature of the heat-consuming equipment 16.

[0033] Temperature sensor 8 monitors the circulating fluid temperature in fourth supply pipe 7b in real time. When the circulating fluid temperature in fourth supply pipe 7b exceeds the heat demand temperature, it indicates that the working fluid temperature in first heat exchange pipeline 4 is continuously rising. At this point, electrical control between temperature sensor 8 and reversing valve 3 causes reversing valve 3 to decrease its outlet opening toward first heat exchange pipeline 4 and increase its outlet opening toward second heat exchange pipeline 5. While maintaining the total flow rate in first and second heat exchange pipelines 4, 5, the working fluid flow rate in first heat exchange pipeline 4 is reduced, maintaining a stable heat exchange power between first heat exchange section 4b and fourth heat exchange section 7a. This further ensures the temperature stability of the circulating fluid in circulating heat supply pipeline 7 and limits the upper temperature limit of the circulating fluid, thereby ensuring that the circulating fluid temperature precisely meets the heat demand temperature.

[0034] When the circulating fluid temperature in the fourth supply pipe 7b falls below the required heat temperature, the heat exchange efficiency between the first heat exchange section 4b and the fourth heat exchange section 7a is insufficient to meet the required heat. Electrical control between the temperature sensor 8 and the reversing valve 3 causes the reversing valve 3 to open wider toward the first heat exchange pipe 4 and narrow toward the second heat exchange pipe 5. While maintaining the total flow rate in the first and second heat exchange pipes 4, the working fluid flow rate in the first heat exchange pipe 4 is increased, increasing the heat exchange efficiency between the first and fourth heat exchange sections 4b and 7a until the circulating fluid temperature in the fourth supply pipe meets the required heat temperature.

[0035] If the outlet opening of reversing valve 3 toward the first heat exchange pipeline 4 is adjusted to its maximum, and the circulating fluid temperature in fourth liquid supply pipe 7b is still lower than the required heat temperature, this indicates that the working fluid temperature in first heat exchange section 4b is too low, and after heat exchange, the circulating fluid temperature cannot meet the required heat temperature. At this point, the outlet of reversing valve 3 toward the first heat exchange pipeline 4 must be closed, allowing all the working fluid pumped by first circulating pump 2 to flow to the second heat exchange pipeline 5, where heat is output at the second heat exchange section 5b. The working fluid temperature in the second heat exchange section 5b fluctuates widely and is relatively low, making it suitable for supplying heat to heat-consuming equipment 16 with lower requirements for temperature fluctuations or highs and lows, or for directly eliminating the heat in the second heat exchange section 5b through cooling.

[0036] Specifically, in conjunction with Figure 2 As shown, a cooling tower 18 is connected to the second heat exchange section 5b to cool the working fluid in the second heat exchange pipeline 5. Alternatively, the second heat exchange section 5b can be used to supply heat to equipment with low temperature fluctuations and high and low temperature requirements, such as office heating systems.

[0037] It should be noted that when the reversing valve 3 is closed toward the outlet of the first heat exchange pipeline 4, no working fluid flows in the first heat exchange pipeline 4, that is, there is no heat exchange between the first heat exchange section 4b and the fourth heat exchange section 7a. At this time, the temperature of the circulating fluid flowing in the circulating heat supply pipeline 7 must not meet the required heat temperature, that is, the outlet of the reversing valve 3 toward the first heat exchange pipeline 4 will remain closed. At this time, even if the third heat exchange section 6b absorbs excess heat, causing the working fluid in the container 1 to reach a higher temperature, and at this temperature, the heat exchange between the first heat exchange section 4b and the fourth heat exchange section 7a can bring the circulating fluid temperature to the required heat temperature, the reversing valve 3 toward the outlet of the first heat exchange pipeline 4 will still remain closed.

[0038] Therefore, when the reversing valve 3 is closed toward the outlet of the first heat exchange pipeline 4, the reversing valve 3 can be opened toward the outlet of the first heat exchange pipeline 4 through manual intervention, so that the working fluid flows in the first heat exchange pipeline 4 and exchanges heat with the circulating fluid in the fourth heat exchange section 7a at the first heat exchange section 4b.

[0039] The advantage of manual intervention is that when the reversing valve 3 is manually opened toward the outlet of the first heat exchange pipeline 4, the heat exchange between the fifth heat exchange section 7c and the heat-consuming device 16 can be simultaneously intervened. Since the circulating fluid in the circulating heat supply pipeline 7 is at a low temperature when the reversing valve 3 is first opened toward the outlet of the first heat exchange pipeline 4, even if the first heat exchange section 4b and the fourth heat exchange section 7a heat exchange to raise the circulating fluid temperature, the circulating fluid temperature cannot immediately reach the required heat demand. To prevent the low-temperature circulating fluid from affecting the production of the heat-consuming device 16, when the reversing valve 3 is manually opened toward the outlet of the first heat exchange pipeline 4, the fifth heat exchange section 7c is simultaneously intervened to prevent the fifth heat exchange section 7c from supplying heat to the heat-consuming device 16. After a certain period of manual intervention, the manual intervention is discontinued, and automatic electrical control is established between the temperature sensor 8 and the reversing valve 3.

[0040] Of course, a thermometer (not shown) can also be provided to monitor the temperature of the working fluid in container 1, thereby opening the reversing valve 3 toward the outlet of the first heat exchange pipeline 4. Specifically, the thermometer is also electrically connected to the reversing valve 3. When the thermometer detects that the working fluid temperature in container 1 reaches a certain threshold, the reversing valve 3 is controlled to open toward the outlet of the first heat exchange pipeline 4, allowing the working fluid to flow through the first heat exchange pipeline 4 and exchange heat with the circulating fluid in the fourth heat exchange section 7a at the first heat exchange section 4b, raising the circulating fluid temperature above the required heat demand.

[0041] It should be noted that it takes a certain amount of time for the circulating fluid to reach a temperature above the required heat temperature. When the thermometer controls the reversing valve 3 to open toward the outlet of the first heat exchange pipeline 4, the temperature sensor 8 detects that the circulating fluid temperature is still below the required heat temperature and controls the reversing valve 3 to close toward the outlet of the first heat exchange pipeline 4.

[0042] To avoid control errors, a time relay (not shown) can be used to set a delay time. The time relay operates when the thermometer controls the opening of reversing valve 3 toward the outlet of first heat exchange pipeline 4. While the time relay is operating for less than the delay time, reversing valve 3 is electrically controlled by the thermometer. After the time relay has operated for the delay time, reversing valve 3 is electrically controlled by temperature sensor 8.

[0043] The heat exchange efficiency between the first heat exchange section 4b and the fourth heat exchange section 7a directly affects the setting of the delay time and the operating efficiency of the waste heat recovery device. Figure 2 As shown, a plate heat exchanger 17 is arranged at the first heat exchange section 4b and the fourth heat exchange section 7a, so that the first heat exchange section 4b serves as the heat source side of the plate heat exchanger 17, and the fourth heat exchange section 7a serves as the cold source side of the plate heat exchanger 17, so as to improve the heat exchange efficiency between the first heat exchange section 4b and the fourth heat exchange section 7a.

[0044] In some preferred embodiments, as shown in the attached Figure 1 , Attachment Figure 2 As shown, a driving pump 9 for driving the flow of the working fluid or the circulating fluid is provided in the waste heat recovery pipeline 6 and / or the circulating heating pipeline 7. Specifically, a driving pump 9 is provided on the third liquid supply pipe 6a of the waste heat recovery pipeline 6, and the driving pump 9 provides a driving force to cause the working fluid to circulate between the waste heat recovery pipeline 6 and the container 1. A driving pump 9 is provided on the fourth liquid supply pipe 7b of the circulating heating pipeline 7, and the driving pump 9 provides a driving force to cause the circulating fluid to circulate in the circulating heating pipeline 7. Generally, both the driving pump 9 and the first circulating pump 2 can adopt variable frequency pumps to meet more driving requirements such as constant flow operation, so as to ensure that the liquid flow rate in the pipeline remains stable.

[0045] The second aspect of the present invention provides a vacuum system, which applies the waste heat recovery device of any of the above embodiments. Figure 3 and attached Figure 4 The vacuum system also includes a vacuum pump 10 and a vacuum tank 11. The inlet end 10c of the vacuum pump 10 is connected to the inside of the vacuum tank 11 via a connecting pipe 12. The third heat exchange section 6b in the waste heat recovery and treatment device is used to absorb the waste heat generated during the operation of the vacuum pump 10 through heat exchange. Specifically, during the operation of the vacuum system, the vacuum pump 10 will generate a large amount of heat. The surplus heat generated by the vacuum pump 10 is absorbed by the third heat exchange section 6b in a heat exchange manner to ensure the stable operation of the vacuum pump 10. In addition, a sewage outlet 15 is provided at the bottom of the vacuum tank 11, and the sewage outlet 15 is used to discharge the dirt in the vacuum tank 11.

[0046] In some preferred embodiments, when the vacuum pump 10 uses liquid as the working medium, the working liquid supply section and the outlet end 10b of the vacuum pump 10 are connected to the third heat exchange section 6b along the working liquid flow direction. Figure 5 , the liquid ring vacuum pump 10 uses liquid as the working medium. The liquid ring vacuum pump 10 has a supply end 10a, an outlet end 10b and an inlet end 10c. Specifically, the supply end 10a is connected to the third liquid supply pipe 6a, the inlet end 10c is connected to the connecting pipe 12, and the outlet end 10b is connected to the third liquid return pipe 6c. In this embodiment, the working fluid in the waste heat recovery treatment device also serves as the working medium of the liquid ring vacuum pump 10. The working fluid enters the pump from the supply end 10a and is discharged from the outlet end 10b after mixing with the gas. In order to meet the linkage requirements, the working fluid uses a liquid that can be used by both the vacuum pump 10 and the waste heat recovery treatment device.

[0047] In addition, combined with the Figure 3 and attached Figure 4In this embodiment, the driving force for the flow of the working fluid can be supplied by the vacuum pump 10. Therefore, when the vacuum pump 10 uses liquid as the working medium, there is no need to configure the drive pump 9 in the waste heat recovery pipeline 6. Similarly, the fifth heat exchange pipe can also be connected to the heat-using device 16, and the circulating fluid is driven to flow by the driving component in the heat-using device 16. At this time, there is no need to configure the drive pump 9 in the circulating heat supply pipeline 7. It should be noted that the circulating fluid must be a liquid suitable for the corresponding heat-using device 16. Among them, the circulating liquid and the working fluid are not directly contacted and mixed, that is, the types of the circulating liquid and the working fluid can be different, and even the circulating medium in the circulating heat supply pipeline 7 can be a gas medium, that is, the first heat exchange section 4b and the fourth heat exchange section 7a are gas-liquid heat exchange.

[0048] In some preferred embodiments, a cavitation protection line 13 is connected between the container 1 and the interior of the vacuum pump 10. Figure 4 and attached Figure 5 When the vacuum pump 10 uses liquid as the working medium, cavitation will occur inside the vacuum pump 10. A cavitation protection port 10d connected to the interior is provided on the vacuum pump 10. By inputting pressure at the cavitation protection port 10d, the liquid pressure therein is always higher than the saturated vapor pressure, thereby suppressing the formation of bubbles and thus suppressing cavitation, reducing wear and damage to components inside the vacuum pump 10 and extending the service life of the vacuum pump 10. In this embodiment, the pressure input at the cavitation protection port 10d comes from the pressure in the container 1. In addition, in the attached Figure 4 and attached Figure 5 In the figure, solid arrows are used to indicate the flow direction of the air extracted from the vacuum tank 11 by the vacuum pump 10. In other figures, hollow arrows are used to indicate the flow direction of the liquid medium or the gas-water mixture.

[0049] In some preferred embodiments, as shown in the attached Figure 6 As shown, the container 1 adopts a gas-water separator, and the gas-water separator is provided with a water supply port 1a, a drain port 1b, an overflow port 1c and an exhaust port 1d. Specifically, the gas-water separator is a device that separates gas from liquid. When the working fluid flows through the inside of the vacuum pump 10, it will mix with the air extracted by the vacuum pump 10, and then flow back into the container 1 through the third return liquid pipe 6c. Since the increase of gas will cause the internal pressure of the container 1 to increase, the use of a gas-water separator can separate the gas from the liquid, and discharge the gas through the exhaust port 1d to achieve the purpose of regulating the pressure, ensuring that the device operates within a safe pressure range. Generally, the separated gas is in the upper layer of the container 1, and the exhaust port 1d is opened at the top of the container 1 for easy exhaust.

[0050] Furthermore, during operation, the working fluid may be lost due to evaporation, leakage, or other factors. If the working fluid level in container 1 falls below the low-level threshold, the refill port 1a is opened to facilitate refilling of the working fluid into container 1. Otherwise, the status quo remains. If the working fluid level falls below the shutdown threshold, the entire waste heat recovery and treatment device must be shut down. Otherwise, the working fluid must be refilled. The shutdown threshold is lower than the low-level threshold. The refill port 1a is typically located at the top of container 1 to facilitate refilling of the working fluid.

[0051] Overflow port 1c is used to limit the upper limit of the liquid level in container 1. It is typically located in the upper half of container 1, a certain distance from the top. This provides space at the top of container 1 for air separation and prevents excessive working fluid buildup. Drain port 1b is located at the bottom of container 1 to facilitate the complete drainage of working fluid from container 1 during maintenance.

[0052] In some preferred embodiments, when the vacuum pump 10 uses gas as the working medium, the third heat exchange section 6b exchanges heat with the gas discharged from the vacuum pump 10. Figure 7 As shown, in a vacuum pump 10 using gas as the working medium, the gas medium is input at the supply end 10a, and the gas medium and air extracted from the vacuum tank 11 are discharged at the outlet end 10b. Heat generated by the operation of the vacuum pump 10 is carried away from the outlet end 10b by the gas, and the third heat exchange section 6b exchanges heat with the high-temperature gas at the outlet end 10b to absorb the waste heat generated by the operation of the vacuum pump 10.

[0053] In some preferred embodiments, there are several vacuum pumps 10 and they are arranged in parallel. Figure 8 and attached Figure 9 As shown, in this embodiment, three liquid ring vacuum pumps 10 are provided and connected in parallel to the third heat exchange section 6b and the connecting pipe 12. Figure 9 In the figure, the third liquid supply pipe 6a and the cavitation protection pipe 13 are both shown in a disconnected form to avoid any intersection between the cavitation protection pipe 13 and the connecting pipe 12 and between the third liquid supply pipe 6a and the third liquid return pipe 6c.

[0054] By connecting any one of the three vacuum pumps 10 in parallel and operating it, vacuum treatment of the vacuum tank 11 and circulation of the working fluid in the waste heat recovery pipeline 6 can be achieved.

[0055] In some preferred embodiments, when the pressure in the vacuum tank 11 is lower than the set lower limit pressure and all the vacuum pumps 10 put into operation are operating at full frequency, the number of the vacuum pumps 10 put into operation is increased; when the pressure in the vacuum tank 11 is higher than the set upper limit pressure and all the vacuum pumps 10 put into operation are operating at the lowest frequency, and the number of vacuum pumps 10 put into operation is at least two, the number of vacuum pumps 10 put into operation is reduced.

[0056] Specifically, a vacuum pressure gauge 14 can be provided in the vacuum tank 11 to monitor the pressure in the vacuum tank 11. In this embodiment, the pressure in the vacuum tank 11 is adjusted by increasing or decreasing the number of vacuum pumps 10 put into operation. When the vacuum demand of the vacuum tank 11 increases or decreases, the pressure in the vacuum tank 11 can also be adjusted by adjusting the operating frequency of the vacuum pump 10. Generally, the operating efficiency of the vacuum pump 10 is adjusted first to adjust the pressure in the vacuum tank 11. When the operating frequency of the vacuum pump 10 is adjusted to the maximum or minimum, and it still cannot meet the vacuum demand in the vacuum tank 11, the pressure in the vacuum tank 11 is adjusted by adjusting the number of vacuum pumps 10 put into operation. Of course, in actual production, the operating efficiency adjustment and the operation number adjustment of the vacuum pump 10 can be carried out simultaneously.

[0057] The specific implementation steps of increasing or decreasing the vacuum tank 11 in this embodiment are as follows: Set the adjustment period T; During the adjustment period T, the pressure in the vacuum tank 11 is collected and recorded every a seconds; After an adjustment period T, the pressure average value ZK_P of all pressure values collected during this adjustment period T is obtained. 平均 .

[0058] when: The following conditions are met for n consecutive cycles: The average pressure value ZK_P in this adjustment cycle T 平均 Lower than the average pressure value ZK_P in the previous adjustment cycle 平均 , and the average pressure ZK_P in this adjustment period T 平均 Compared with the average pressure ZK_P in the previous adjustment cycle 平均 When the ratio is less than the set ratio α, it indicates that the pressure in the vacuum tank 11 is in a continuously decreasing state; If the average pressure ZK_P 平均 Lower than the set lower limit pressure ZK_P 下限 When all the vacuum pumps 10 in operation are in full-frequency operation, the number of vacuum pumps 10 put into operation is increased.

[0059] when: The following conditions are met for n consecutive cycles: The average pressure value ZK_P in this adjustment cycle T 平均 Higher than the average pressure ZK_P in the previous adjustment cycle 平均, and the average pressure ZK_P in this adjustment period T 平均 Compared with the average pressure ZK_P in the previous adjustment cycle 平均 When the ratio is greater than the set ratio β, it indicates that the pressure in the vacuum tank 11 is in a continuously increasing state; If the average pressure ZK_P 平均 Higher than the set upper limit pressure ZK_P 上限 When all the vacuum pumps 10 in operation are in the lowest frequency operation state and there are at least two vacuum pumps 10 in operation, the number of vacuum pumps 10 in operation is reduced.

[0060] A third aspect of the present invention further provides a recovery method using the waste heat recovery device of any of the above embodiments. Specifically, the recovery method comprises the following steps: Obtaining the temperature of the circulating liquid in the fourth liquid supply pipe 7b; If the circulating liquid temperature meets the heat demand temperature of the heat-using device 16, the reversing valve 3 is kept connected to only the first liquid supply pipe 4a; If the circulating fluid temperature is higher than the heat demand temperature of the heat-consuming device 16, the opening of the reversing valve 3 connected to the first liquid supply pipe 4a is reduced and the opening of the reversing valve 3 connected to the second liquid supply pipe 5a is increased; If the temperature of the circulating fluid is lower than the heat demand temperature of the heat-consuming device 16, the reversing valve 3 is kept in communication with only the second liquid supply pipe 5a.

[0061] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0062] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0063] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A waste heat recovery device, characterized in that: include: A container (1), wherein the container (1) contains a working fluid; a first circulation pump (2), wherein a liquid inlet of the first circulation pump (2) is connected to the interior of the container (1); a reversing valve (3), wherein the liquid inlet of the reversing valve (3) is connected to the liquid outlet of the first circulating pump (2); a first heat exchange pipeline (4), the first heat exchange pipeline (4) comprising a first liquid supply pipe (4a), a first heat exchange section (4b), and a first liquid return pipe (4c) which are sequentially connected along the flow direction of the working fluid, the first liquid supply pipe (4a) being connected to one of the liquid outlets of the reversing valve (3), and the first liquid return pipe (4c) being connected to the container (1) at one end away from the first heat exchange section (4b); a second heat exchange pipeline (5), the second heat exchange pipeline (5) comprising a second liquid supply pipe (5a), a second heat exchange section (5b) and a second liquid return pipe (5c) which are sequentially connected along the flow direction of the working fluid, the second liquid supply pipe (5a) being connected to the other liquid outlet of the reversing valve (3), and the second liquid return pipe (5c) being connected to the container (1) at one end away from the second heat exchange section (5b); A waste heat recovery pipeline (6), the waste heat recovery pipeline (6) comprising a third liquid supply pipe (6a), a third heat exchange section (6b), and a third liquid return pipe (6c) sequentially connected along the flow direction of the working fluid, the third liquid supply pipe (6a) and the third liquid return pipe (6c) having ends away from the third heat exchange section (6b) both connected to the container (1); A circulating heat supply pipeline (7), the circulating heat supply pipeline (7) comprising a fourth heat exchange section (7a), a fourth liquid supply pipe (7b), a fifth heat exchange section (7c), and a fourth liquid return pipe (7d) connected end to end in sequence, the fourth heat exchange section (7a) exchanging heat with the first heat exchange section (4b); A temperature sensor (8), the temperature sensor (8) is used to monitor the temperature of the circulating liquid in the fourth liquid supply pipe (7b), and the temperature sensor (8) is electrically connected to the reversing valve (3).

2. The waste heat recovery device according to claim 1, characterized in that: A driving pump (9) for driving the flow of working fluid or circulating fluid is provided in the waste heat recovery pipeline (6) and / or the circulating heat supply pipeline (7).

3. A vacuum system using the waste heat recovery device according to claim 1 or 2, characterized in that: The vacuum system further comprises a vacuum pump (10) and a vacuum tank (11), wherein an inlet end (10c) of the vacuum pump (10) is connected to the interior of the vacuum tank (11) via a connecting pipe (12); The third heat exchange section (6b) in the waste heat recovery and treatment device is used for heat exchange and absorption of waste heat generated during the operation of the vacuum pump (10).

4. The vacuum system according to claim 3, characterized in that When the vacuum pump (10) uses liquid as a working medium, the working liquid supply end (10a) and the outlet end (10b) of the vacuum pump (10) are connected to the third heat exchange section (6b) along the flow direction of the working liquid.

5. The vacuum system according to claim 4, characterized in that A cavitation protection pipeline (13) is connected between the container (1) and the interior of the vacuum pump (10).

6. The vacuum system according to claim 5, characterized in that The container (1) adopts an air-water separator, and the air-water separator is provided with a water supply port (1a), a water discharge port (1b), an overflow port (1c) and an air exhaust port (1d).

7. The vacuum system according to claim 3, characterized in that When the vacuum pump (10) uses gas as a working medium, the third heat exchange section (6b) exchanges heat with the gas discharged from the vacuum pump (10).

8. The vacuum system according to any one of claims 3 to 7, characterized in that The vacuum pumps (10) are provided in plurality and are arranged in parallel.

9. The vacuum system according to claim 8, characterized in that When the pressure in the vacuum tank (11) is lower than a set lower limit pressure and all the vacuum pumps (10) put into operation are operating at full frequency, the number of the vacuum pumps (10) put into operation is increased; When the pressure in the vacuum tank (11) is higher than the set upper limit pressure, and all the vacuum pumps (10) put into operation are operating at the lowest frequency, and the number of the vacuum pumps (10) put into operation is at least two, the number of the vacuum pumps (10) put into operation is reduced.

10. A waste heat recovery method using the waste heat recovery device according to claim 1 or 2, characterized in that: The steps include: Obtaining the temperature of the circulating liquid in the fourth liquid supply pipe (7b); If the temperature of the circulating liquid meets the heat demand temperature of the heat-using device (16), the reversing valve (3) is kept connected to only the first liquid supply pipe (4a); If the temperature of the circulating fluid is higher than the heat demand temperature of the heat-consuming device (16), the opening of the reversing valve (3) connected to the first liquid supply pipe (4a) is reduced and the opening of the reversing valve (3) connected to the second liquid supply pipe (5a) is increased; If the temperature of the circulating liquid is lower than the heat demand temperature of the heat-consuming device (16), the reversing valve (3) is kept connected only to the second liquid supply pipe (5a).

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