A steam waste heat recovery system and method

Abstract

The application discloses a steam waste heat recycling system, which comprises a first air inlet pipe, a first pressure sensor, a first water inlet pipe, a first valve, a deaerator and the like, wherein the heat exchanger is used for heat exchange between steam in the first air inlet pipe and water in the first water inlet pipe, so as to heat the water in the first water inlet pipe; when the pressure collected by the first pressure sensor exceeds the preset pressure and / or the temperature collected by the temperature sensor exceeds the preset temperature, the control part controls the opening of the first valve to increase; when the pressure collected by the first pressure sensor does not exceed the preset pressure and / or the temperature collected by the temperature sensor does not exceed the preset temperature, the control part controls the opening of the first valve to decrease or keeps the opening of the first valve as the minimum opening. The application can prevent the deaerator from being damaged due to violent vibration, and can also release the steam pressure when the steam pressure is too large, so as to prevent safety hazards. The application further discloses a steam waste heat recycling method.

Description

Technical Field

[0001] This invention relates to the field of steam recovery and utilization technology, and in particular to a steam waste heat recovery and utilization system and method. Background Technology

[0002] Many production lines and equipment in cigarette manufacturing companies utilize steam (temperatures above 100°C), such as the steam used in the tobacco processing to heat and rehydrate the tobacco leaves. After being used by upstream steam-consuming equipment, the steam becomes low-quality steam (the pressure decreases after passing through upstream equipment, but the temperature remains above 100°C, hence the term "low-quality steam"). To utilize the waste heat of this steam, production lines are typically equipped with a steam waste heat recovery system to recover and reuse the residual heat from the steam.

[0003] The existing steam waste heat recovery system includes a heat exchanger, a first water supply pump, a condensate collection tank, a deaerator, a second water supply pump, and a boiler. The first water supply pump pumps ambient temperature water into the system, which flows through the heat exchanger. Steam used by upstream steam-consuming equipment also enters the heat exchanger. The heat exchanger allows heat exchange between the water and steam, using the steam's heat to heat the ambient temperature water to a preset temperature (85°C) to form hot water. This hot water is then sent to the deaerator, which removes oxygen before sending it to the boiler via the second water supply pump for further use. The steam after heat exchange becomes condensate (temperature reduced, but still higher than ambient temperature water, approximately 90-100°C) and enters the condensate collection tank, which is connected to the deaerator's inlet. As the pressure decreases after entering the condensate collection tank, some of the liquid water turns into flash steam and is reused in the heat exchanger, while the other part of the liquid water is recycled into the deaerator through the delivery pipeline.

[0004] However, existing waste heat recovery steam systems often suffer from severe deaerator vibration and damage, or excessive steam pressure that cannot be effectively released, posing safety hazards. Summary of the Invention

[0005] The purpose of this invention is to solve the safety hazards caused by frequent deaerator damage and excessive steam pressure in existing steam waste heat recovery systems. This invention provides a steam waste heat recovery system and method that can prevent severe vibration of the deaerator, thus preventing deaerator damage, and can also release steam pressure when it is too high, thereby preventing safety hazards.

[0006] The inventors discovered that the main reasons for frequent deaerator damage and excessive steam pressure in current steam waste heat recovery systems are: unstable gas consumption from upstream equipment causes fluctuations in the amount of steam entering the heat exchanger, resulting in a fluctuating ratio of steam to ambient temperature water. When the steam volume suddenly decreases, if the ambient temperature water intake remains constant, a large amount of ambient temperature water will not receive effective heat exchange, leading to lower water temperatures entering the deaerator. When this water comes into contact with the high-temperature water and steam (the deaerator is a gas-liquid mixture) in the deaerator, the steam in the deaerator cools and condenses, reducing the amount of steam in the deaerator and consequently lowering the pressure. Then, the water entering the deaerator is heated to a high temperature and turns back into steam, increasing the amount of steam in the deaerator and further increasing the pressure. This pressure fluctuation causes severe vibration in the deaerator, making it prone to damage. Furthermore, when the steam pressure entering the heat exchanger suddenly increases, if the ambient temperature water entering the heat exchanger remains at the original flow rate, a large amount of steam will not be able to condense, resulting in the steam pressure not being effectively released. If the steam pressure remains too high for a long time, safety hazards may arise.

[0007] To address the aforementioned technical problems, according to a first aspect of the present invention, an embodiment of the present invention discloses a steam waste heat recovery and utilization system, comprising:

[0008] The first air inlet pipe has an air inlet end connected to a steam source. The first air inlet pipe is equipped with a first pressure sensor, which is used to collect the pressure of the steam in the first air inlet pipe.

[0009] The condensate collection tank is connected to the outlet end of the first air inlet pipe;

[0010] The first water inlet pipe has its inlet end connected to a water source. The first water inlet pipe is equipped with a first water supply pump and a first valve. The first valve is used to regulate the opening and closing of the first water inlet pipe.

[0011] The deaerator is connected to the outlet end of the first inlet pipe;

[0012] The heat exchanger has both a first air inlet pipe and a first water inlet pipe passing through it. The heat exchanger is used to exchange heat between the steam in the first air inlet pipe and the water in the first water inlet pipe, so as to raise the temperature of the water in the first water inlet pipe.

[0013] A temperature sensor is installed on the first inlet pipe, and the temperature sensor is located between the heat exchanger and the outlet end of the first inlet pipe. The temperature sensor is used to collect the temperature of the water after heat exchange through the heat exchanger.

[0014] The control unit is electrically connected to the first pressure sensor, the first valve, and the temperature sensor respectively. When the pressure collected by the first pressure sensor exceeds the preset pressure and / or the temperature collected by the temperature sensor exceeds the preset temperature, the control unit controls the opening of the first valve to increase. When the pressure collected by the first pressure sensor does not exceed the preset pressure and / or the temperature collected by the temperature sensor does not exceed the preset temperature, the control unit controls the opening of the first valve to decrease or maintains the opening of the first valve at the minimum opening.

[0015] Using the above technical solution, when the pressure of the first pressure sensor exceeds the preset pressure and / or the temperature of the temperature sensor exceeds the preset temperature, it indicates that there is excess steam participating in heat exchange. At this time, the opening of the first valve gradually increases to increase the inflow of ambient temperature water, so that the amount of ambient temperature water matches the amount of steam. This allows excess steam to be utilized through heat exchange, releasing steam pressure and preventing safety hazards. When the pressure of the first pressure sensor does not exceed the preset pressure and / or the temperature of the temperature sensor does not exceed the preset temperature, it indicates that the amount of steam participating in heat exchange is reduced or insufficient. At this time, the opening of the first valve decreases or remains at its minimum opening. This ensures that water always flows in the first inlet pipe, thus ensuring that the temperature sensor installed on the first inlet pipe can work normally (if the first valve is completely closed, the water in the first inlet pipe will not flow, and the temperature sensor will detect inaccurately). It also reduces the inflow of ambient temperature water, preventing a large amount of ambient temperature water from directly entering the deaerator without heat exchange, causing severe vibration and damage to the deaerator.

[0016] The inventors also discovered that because the condensate collection tank is relatively large, the pressure drops after the condensate enters it. This pressure drop causes some of the condensate to turn into steam (a process known as flash evaporation), which accumulates above the condensate collection tank. When there is excessive steam above the condensate collection tank, the pressure above it exceeds the pressure in the first air inlet pipe and the preset pressure, posing a safety hazard of explosion.

[0017] Therefore, according to another specific embodiment of the present invention, the steam waste heat recovery and utilization system of the present invention further includes:

[0018] The second air inlet pipe has an outlet end connected to the first air inlet pipe and an inlet end connected to the upper part of the condensate collection tank. The second air inlet pipe is equipped with a one-way valve and a second valve. The one-way valve allows steam in the second air inlet pipe to flow from the inlet end to the outlet end of the second air inlet pipe, and the second valve is used to control the opening and closing of the second air inlet pipe.

[0019] The second pressure sensor is located at the top of the condensate collection tank. The second pressure sensor is used to collect the pressure of the steam at the top of the condensate collection tank.

[0020] The control unit is also electrically connected to the second pressure sensor and the second valve; when the pressure of the second pressure sensor exceeds the pressure of the first pressure sensor and the pressure of the second pressure sensor exceeds the preset pressure, the control unit controls the opening of the second valve to increase; when the pressure of the second pressure sensor does not exceed the pressure of the first pressure sensor and / or the pressure of the second pressure sensor does not exceed the preset pressure, the control unit controls the opening of the second valve to decrease.

[0021] Using the above technical solution, when the pressure of the second pressure sensor exceeds the pressure of the first pressure sensor and also exceeds a preset pressure, the opening of the second valve is increased to allow steam in the condensate collection tank to flow into the first air inlet pipe, thereby reducing the pressure in the condensate collection tank and decreasing the probability of an explosion. When the pressure of the second pressure sensor does not exceed the pressure of the first pressure sensor and / or does not exceed the preset pressure, the control unit controls the opening of the second valve to decrease to prevent excessive steam from entering the first air inlet pipe and causing excessive pressure in the first air inlet pipe, which could pose a safety hazard.

[0022] According to another specific embodiment of the present invention, the steam waste heat recovery and utilization system of the present invention further includes:

[0023] The deaerator is also equipped with a liquid level sensor, which is used to detect the actual liquid level in the deaerator.

[0024] The control unit is also electrically connected to the liquid level sensor. When the actual liquid level in the deaerator exceeds the preset liquid level, the control unit controls the first valve to adjust to the minimum opening. When the actual liquid level in the deaerator does not exceed the preset liquid level, the control unit controls the opening of the first valve to increase.

[0025] Using the above technical solution, when the actual liquid level in the deaerator exceeds the preset liquid level, the first valve maintains its minimum opening. This ensures the temperature sensor functions properly and prevents excessive water intake and overflow. Furthermore, since the deaerator supplies water to the boiler via a second water supply pump, if the liquid level in the deaerator is too low, steam from the deaerator will enter the second water supply pump, potentially causing cavitation and shortening its lifespan. Therefore, when the actual liquid level in the deaerator does not exceed the preset liquid level, the opening of the first valve is increased to bring the actual liquid level closer to the preset level, thus preventing cavitation in the second water supply pump.

[0026] According to a second aspect of the present invention, a method for recovering and utilizing waste steam heat is also disclosed for use in the aforementioned waste steam heat recovery and utilization system, the method comprising:

[0027] Collect the outlet water temperature of the heat exchanger and the pressure of the first air inlet pipe, and determine whether the outlet water temperature of the heat exchanger exceeds the preset temperature and whether the pressure of the first air inlet pipe exceeds the preset pressure.

[0028] If the outlet water temperature of the heat exchanger exceeds the preset temperature, and / or the pressure of the first air inlet pipe exceeds the preset pressure, then increase the opening of the first valve;

[0029] If the outlet water temperature of the heat exchanger does not exceed the preset temperature, and / or the pressure of the first air inlet pipe does not exceed the preset pressure, then determine whether the opening degree of the first valve is greater than the minimum opening degree.

[0030] If yes, reduce the opening of the first valve to the minimum opening; if no, keep the opening of the first valve unchanged.

[0031] According to another specific embodiment of the present invention, before determining whether the outlet water temperature of the heat exchanger exceeds the preset temperature and whether the pressure of the first air inlet pipe exceeds the preset pressure, the steam waste heat recovery and utilization method of the present invention further includes: collecting the actual liquid level height of the deaerator and determining whether the actual liquid level height of the deaerator exceeds the preset liquid level height.

[0032] If the actual liquid level in the deaerator exceeds the preset liquid level, the opening of the first valve will be adjusted to the minimum opening.

[0033] If the actual liquid level in the deaerator does not exceed the preset liquid level, the opening of the first valve is increased.

[0034] According to another specific embodiment of the present invention, the steam waste heat recovery and utilization method of the present invention further includes: a liquid level sensor is provided on the deaerator, and the actual liquid level height of the deaerator is collected by: collecting the actual liquid level height of the deaerator through the liquid level sensor.

[0035] According to another specific embodiment of the present invention, the steam waste heat recovery and utilization method of the present invention further includes: a temperature sensor is provided on the first water inlet pipe located downstream of the heat exchanger along the water flow direction, and the collection of the outlet water temperature of the heat exchanger includes: collecting the temperature of the water in the first water inlet pipe through the temperature sensor.

[0036] According to another specific embodiment of the present invention, the steam waste heat recovery and utilization method of the present invention further includes: a first pressure sensor is provided on a first inlet pipe located upstream of the heat exchanger along the steam flow direction, and the pressure of the first inlet pipe is collected, including: the first pressure sensor is used to collect the pressure of the steam in the first inlet pipe.

[0037] According to another specific embodiment of the present invention, the steam waste heat recovery and utilization method of the present invention further includes: a second air inlet pipe is provided between the condensate collection tank and the first air inlet pipe, the upper part of the condensate collection tank is connected to the first air inlet pipe through the second air inlet pipe, a one-way valve and a second valve are provided on the second air inlet pipe, the one-way valve allows steam to flow from the condensate collection tank to the first air inlet pipe, and the second valve is used to control the opening and closing of the second air inlet pipe. The steam waste heat recovery and utilization method further includes:

[0038] Collect the pressure of the steam above the condensate collection tank and determine whether the pressure of the steam above the condensate collection tank exceeds the pressure of the first air inlet pipe and the preset pressure;

[0039] If the steam pressure above the condensate collection tank exceeds the pressure of the first air inlet pipe and exceeds the preset pressure, the opening of the second valve is increased; if the steam pressure above the condensate collection tank does not exceed the pressure of the first air inlet pipe and / or does not exceed the preset pressure, the opening of the second valve is decreased.

[0040] According to another specific embodiment of the present invention, the steam waste heat recovery and utilization method of the present invention further includes: the lower part of the condensate collection tank is connected to the deaerator through a second water inlet pipe, and a pressure pump is provided on the second water inlet pipe, the pressure pump being used to transport water in the second water inlet pipe to the deaerator.

[0041] According to another specific embodiment of the present invention, the steam waste heat recovery and utilization method of the present invention further includes: a minimum opening degree of 6%.

[0042] According to another specific embodiment of the present invention, the steam waste heat recovery and utilization method of the present invention further includes: setting the preset liquid level height to 1.1m.

[0043] According to another specific embodiment of the present invention, the steam waste heat recovery and utilization method of the present invention further includes: a preset temperature of 85°.

[0044] According to another specific embodiment of the present invention, the steam waste heat recovery and utilization method of the present invention further includes: a preset pressure of 10000 Pa. Attached Figure Description

[0045] Figure 1 This diagram shows a schematic representation of the steam waste heat recovery and utilization system disclosed in an embodiment of the present invention.

[0046] Figure 2 The flowchart of the steam waste heat recovery and utilization method disclosed in the embodiments of the present invention is shown. Figure 1 ;

[0047] Figure 3 The flowchart of the steam waste heat recovery and utilization method disclosed in the embodiments of the present invention is shown. Figure 2 .

[0048] Figure 4 The flowchart of the steam waste heat recovery and utilization method disclosed in the embodiments of the present invention is shown. Figure 3 .

[0049] Reference numerals in the attached drawings: 1. Heat exchanger, 2. First water supply pump, 3. Deaerator, 4. Condensate collection tank, 5. First air inlet pipe, 51. Air inlet end of the first air inlet pipe, 52. Air outlet end of the first air inlet pipe, 6. First pressure sensor, 7. First water inlet pipe, 71. Water inlet end of the first water inlet pipe, 72. Water outlet end of the first water inlet pipe, 8. First valve, 9. Temperature sensor, 10. Second water inlet pipe, 11. Second air inlet pipe, 111. Air inlet end of the second air inlet pipe, 112. Air outlet end of the second air inlet pipe, 12. Second valve, 13. Second pressure sensor, 14. Liquid level sensor, 15. Pressure pump. Detailed Implementation

[0050] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a deep understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0051] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0052] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of the invention is usually placed in during use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0053] The terms “first”, “second”, etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0054] In the description of this embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0055] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0056] According to a first aspect of the present invention, the present invention provides a steam waste heat recovery and utilization system, such as Figure 1 As shown, the system includes a heat exchanger 1, a first water supply pump 2, a deaerator 3, a second water supply pump (not shown in the figure), a condensate collection tank 4, a first air inlet pipe 5, a first pressure sensor 6, a first water inlet pipe 7, a first valve 8, a temperature sensor 9, a second water inlet pipe 10, and a control unit (not shown in the figure).

[0057] The first air inlet pipe 5 has its inlet end connected to a steam source, and its outlet end connected to a condensate collection tank 4. The first water inlet pipe 7 has its inlet end connected to a room temperature water source, and its outlet end connected to a deaerator 3. A first water supply pump 2 is installed on the first water inlet pipe 7 to pump room temperature water into the deaerator 3. Both the first air inlet pipe 5 and the first water inlet pipe 7 pass through a heat exchanger 1, which allows the steam in the first air inlet pipe 5 to exchange heat with the water in the first water inlet pipe 7, thereby raising the temperature of the water in the first water inlet pipe 7. The system then sends this hot water to the deaerator 3, where it heats the water and removes oxygen before sending it to the boiler via a second water supply pump for subsequent use. After heat exchange, the steam becomes condensate (its temperature decreases, but it is still higher than room temperature water, approximately 90°C to 100°C) and enters the condensate collection tank 4. The bottom of the condensate collection tank 4 is connected to the inlet of the deaerator 3. Because the pressure decreases after entering the condensate collection tank 4, part of the liquid water becomes flash steam and re-enters the heat exchanger 1 for reuse, while the other part of the liquid water enters the deaerator 3 through the conveying pipeline for recycling.

[0058] A first pressure sensor 6 is installed on the first air inlet pipe 5 to collect the pressure of the steam in the first air inlet pipe 5. A first valve 8 and a temperature sensor 9 are installed on the first water inlet pipe 7. The first valve 8 is an electrically controlled valve used to regulate the opening and closing of the first water inlet pipe 7. The temperature sensor 9 is located between the heat exchanger 1 and the outlet of the first water inlet pipe 7 to collect the temperature of the water after heat exchange in the heat exchanger 1. The control unit is electrically connected to the first pressure sensor 6, the first valve 8, and the temperature sensor 9. When the pressure collected by the first pressure sensor 6 exceeds a preset pressure and / or the temperature collected by the temperature sensor 9 exceeds a preset temperature, the control unit controls the opening of the first valve 8 to increase. When the pressure collected by the first pressure sensor 6 does not exceed the preset pressure and / or the temperature collected by the temperature sensor 9 does not exceed the preset temperature, the control unit controls the opening of the first valve 8 to decrease or maintain the opening of the first valve 8 at its minimum. The preset pressure and preset temperature can be determined according to actual conditions. In this embodiment, the preset pressure is 10000 Pa and the preset temperature is 85°C.

[0059] Using the above technical solution, when the pressure of the first pressure sensor 6 exceeds the preset pressure and / or the temperature of the temperature sensor 9 exceeds the preset temperature, it indicates that there is excess steam participating in heat exchange. At this time, the opening of the first valve 8 gradually increases to increase the inflow of ambient temperature water, so that the amount of ambient temperature water matches the amount of steam. This allows the excess steam to be utilized through heat exchange, releasing the steam pressure and preventing potential safety hazards. When the pressure of the first pressure sensor 6 does not exceed the preset pressure and / or the temperature of the temperature sensor 9 does not exceed the preset temperature, it indicates that the amount of steam participating in heat exchange is reduced or insufficient. At this time, the opening of the first valve 8 decreases or remains at its minimum opening. This ensures that water always flows in the first inlet pipe 7, thus ensuring that the temperature sensor 9 installed on the first inlet pipe 7 can work normally (if the first valve 8 is completely closed, the water in the first inlet pipe 7 does not flow, and the temperature sensor 9 will not detect accurately). On the other hand, it also reduces the inflow of ambient temperature water, preventing a large amount of ambient temperature water from directly entering the deaerator 3 without heat exchange, causing the deaerator 3 to vibrate violently and be damaged.

[0060] The inventors also discovered that because the condensate collection tank 4 is relatively large, the pressure of the condensate decreases after it enters the tank. This pressure drop causes some of the condensate to turn into steam (a process known as flash evaporation), which accumulates above the condensate collection tank 4. When there is excessive steam above the condensate collection tank 4, the pressure above it exceeds the pressure of the first air inlet pipe 5 and the preset pressure, posing a safety hazard of explosion.

[0061] Therefore, according to another specific embodiment of the present invention, the steam waste heat recovery and utilization system of the present invention further includes: a second air inlet pipe 11 and a second pressure sensor 13. (Continue to refer to...) Figure 1 The outlet of the second air inlet pipe 11 is connected to the first air inlet pipe 5, and the inlet of the second air inlet pipe 11 is connected to the upper part of the condensate collection tank 4. The second air inlet pipe 11 is equipped with a one-way valve (not shown in the figure) and a second valve 12. The one-way valve allows steam in the second air inlet pipe 11 to flow from the inlet to the outlet of the second air inlet pipe 11. The second valve 12 controls the opening and closing of the second air inlet pipe 11. The one-way valve prevents steam in the first air inlet pipe 5 from directly entering the condensate collection tank 4 without passing through the heat exchanger 1, which could cause a sudden increase in pressure in the condensate collection tank 4 and lead to a safety accident. A second pressure sensor 13 is located on the upper part of the condensate collection tank 4 and is used to collect the pressure of the steam at the upper part of the condensate collection tank 4. The control unit is also electrically connected to the second pressure sensor 13 and the second valve 12. When the pressure of the second pressure sensor 13 exceeds the pressure of the first pressure sensor 6 and the pressure of the second pressure sensor 13 exceeds the preset pressure, the control unit controls the opening of the second valve 12 to increase; when the pressure of the second pressure sensor 13 does not exceed the pressure of the first pressure sensor 6 and / or the pressure of the second pressure sensor 13 does not exceed the preset pressure, the control unit controls the opening of the second valve 12 to decrease.

[0062] Using the above technical solution, when the pressure of the second pressure sensor 13 exceeds the pressure of the first pressure sensor 6 and also exceeds a preset pressure, the opening of the second valve 12 is increased to allow steam in the condensate collection tank 4 to be transported to the first air inlet pipe 5, thereby reducing the pressure in the condensate collection tank 4 and decreasing the probability of an explosion. When the pressure of the second pressure sensor 13 does not exceed the pressure of the first pressure sensor 6 and / or does not exceed the preset pressure, the control unit controls the opening of the second valve 12 to decrease to prevent excessive steam from entering the first air inlet pipe 5, which could cause excessive pressure in the first air inlet pipe 5 and pose a safety hazard.

[0063] Continue to refer to Figure 1 According to another specific embodiment of the present invention, the steam waste heat recovery system of the present invention further includes a liquid level sensor 14, which is disposed on the deaerator 3. The liquid level sensor 14 is used to detect the actual liquid level height in the deaerator 3. The control unit is also electrically connected to the liquid level sensor 14. When the actual liquid level height in the deaerator 3 exceeds the preset liquid level height, the control unit controls the first valve 8 to adjust to the minimum opening degree. When the actual liquid level height in the deaerator 3 does not exceed the preset liquid level height, the control unit controls the opening degree of the first valve 8 to increase. The preset liquid level height can be determined according to the actual situation. In this embodiment, the preset liquid level height is 1.1m.

[0064] Using the above technical solution, when the actual liquid level in deaerator 3 exceeds the preset liquid level, the first valve 8 maintains its minimum opening. This ensures the temperature sensor 9 functions properly and prevents excessive water intake and overflow. Furthermore, since deaerator 3 supplies water to the boiler via a water pump, if the liquid level in deaerator 3 is too low, steam from deaerator 3 will enter the water pump, easily causing cavitation and shortening its lifespan. Therefore, when the actual liquid level in deaerator 3 does not exceed the preset liquid level, the control unit increases the opening of the first valve 8 to bring the actual liquid level in deaerator 3 closer to the preset liquid level, preventing water pump cavitation.

[0065] According to a second aspect of the present invention, a method for recovering and utilizing waste steam heat is also disclosed for use in the aforementioned waste steam heat recovery and utilization system, with reference to... Figures 1 to 3 The method for recovering and utilizing steam waste heat includes:

[0066] Step S1: Collect the outlet water temperature of heat exchanger 1 (denoted as T) and the steam pressure in the first inlet pipe 5 (denoted as P1), and determine whether the outlet water temperature of heat exchanger 1 exceeds the preset temperature (denoted as T0) and whether the steam pressure in the first inlet pipe 5 exceeds the preset pressure (denoted as P0).

[0067] Step S2: If the outlet water temperature of heat exchanger 1 exceeds the preset temperature (i.e., P1 > P0), and / or the pressure of the first air inlet pipe 5 exceeds the preset pressure (i.e., T > T0), then increase the opening of the first valve 8.

[0068] Step S3: If the outlet water temperature of heat exchanger 1 does not exceed the preset temperature, and / or the pressure of the first air inlet pipe 5 does not exceed the preset pressure, then determine whether the opening degree of the first valve 8 is greater than the minimum opening degree. Specifically, the inventors considered that if the first valve 8 is completely closed, water will not flow in the first water inlet pipe 7, and the temperature sensor 9 will not be able to detect the water temperature in the first water inlet pipe 7. Therefore, the first valve 8 is set to not be completely closed to ensure that there is water flow in the first water inlet pipe 7. Specifically, the minimum opening degree of the first valve 8 can be determined according to the actual situation. In this embodiment, the minimum opening degree is 6%.

[0069] Step S4: If the opening of the first valve 8 is greater than the minimum opening, then reduce the opening of the first valve 8 to the minimum opening; if the opening of the first valve 8 is equal to the minimum opening, then keep the opening of the first valve 8 unchanged.

[0070] In particular, the increase of the opening degree of the first valve 8 in step S2 and the decrease of the opening degree of the first valve 8 to the minimum opening degree in step S4 can both be adjusted by PID control method.

[0071] Furthermore, the preset pressure and preset temperature can be determined according to actual conditions. In this embodiment, the preset pressure is 10000 Pa and the preset temperature is 85°C.

[0072] Using the above technical solution, when the pressure of the first pressure sensor 6 exceeds the preset pressure and / or the temperature of the temperature sensor 9 exceeds the preset temperature, it indicates that there is excess steam participating in heat exchange. At this time, the opening of the first valve 8 gradually increases to increase the inflow of ambient temperature water, so that the amount of ambient temperature water matches the amount of steam. This allows the excess steam to be utilized through heat exchange, releasing the steam pressure and preventing potential safety hazards. When the pressure of the first pressure sensor 6 does not exceed the preset pressure and / or the temperature of the temperature sensor 9 does not exceed the preset temperature, it indicates that the amount of steam participating in heat exchange is reduced or insufficient. At this time, the opening of the first valve 8 is reduced or kept at its minimum opening. This ensures that water always flows in the first inlet pipe 7, thus ensuring that the temperature sensor 9 installed on the first inlet pipe 7 can work normally. On the other hand, it also reduces the inflow of ambient temperature water, preventing a large amount of ambient temperature water from directly entering the deaerator 3 without heat exchange, causing the deaerator 3 to vibrate violently and be damaged. In summary, the steam waste heat recovery and utilization method provided by the present invention can adjust the opening of the first valve 8 in real time based on the steam pressure and the outlet water temperature of the heat exchanger 1, so as to match the ratio of steam volume to ambient temperature water inlet volume, thereby preventing the deaerator 3 from vibrating violently and being damaged, or the steam pressure being too high and unable to be effectively released, thus reducing safety hazards.

[0073] According to another specific embodiment of the present invention, reference is made to Figure 1 and Figure 3 Before determining whether the outlet water temperature of heat exchanger 1 exceeds a preset temperature and whether the pressure of the first air inlet pipe 5 exceeds a preset pressure, the steam waste heat recovery and utilization method of the present invention further includes:

[0074] Step S1a: Collect the actual liquid level height of deaerator 3 (referred to as L), and determine whether the actual liquid level height of deaerator 3 exceeds the preset liquid level height (referred to as L0);

[0075] Step S1b: If the actual liquid level of the deaerator 3 exceeds the preset liquid level (i.e., L > L0), then adjust the opening of the first valve 8 to the minimum opening.

[0076] If the actual liquid level in deaerator 3 does not exceed the preset liquid level, then increase the opening of the first valve 8.

[0077] Specifically, the preset liquid level height can be determined according to the actual situation. In this embodiment, the preset liquid level height is 1.1m.

[0078] Using the above technical solution, when the actual liquid level in deaerator 3 exceeds the preset liquid level, the first valve 8 maintains its minimum opening. This ensures the temperature sensor 9 functions properly and prevents excessive water intake and overflow. Furthermore, since deaerator 3 supplies water to the boiler via a water pump, if the liquid level in deaerator 3 is too low, steam from deaerator 3 will enter the water pump, easily causing pump cavitation and shortening its lifespan. Therefore, when the actual liquid level in deaerator 3 does not exceed the preset liquid level, the opening of the first valve 8 is increased to bring the actual liquid level in deaerator 3 closer to the preset liquid level, preventing pump cavitation. Setting steps S1a and S1b before step S1 prioritizes ensuring the actual liquid level in deaerator 3 is close to the preset liquid level, guaranteeing normal boiler operation. Step S1 is performed only after the actual liquid level in deaerator 3 exceeds the preset liquid level and the opening of the first valve 8 is adjusted to its minimum.

[0079] According to another specific embodiment of the present invention, the steam waste heat recovery and utilization method of the present invention further includes: a liquid level sensor 14 is provided on the deaerator 3, and the actual liquid level height of the deaerator 3 is collected by: collecting the actual liquid level height of the deaerator 3 through the liquid level sensor 14.

[0080] According to another specific embodiment of the present invention, reference is made to Figure 1 The steam waste heat recovery and utilization method of the present invention further includes: along the water flow direction (e.g. Figure 1 (As indicated by the arrow in the solid line), a temperature sensor 9 is installed on the first inlet pipe 7 located downstream of the heat exchanger 1. The temperature of the water outlet of the heat exchanger 1 is collected by the temperature sensor 9, which collects the temperature of the water in the first inlet pipe 7.

[0081] According to another specific embodiment of the present invention, reference is made to Figure 1 The steam waste heat recovery and utilization method of the present invention further includes: along the steam flow direction (e.g. Figure 1 As indicated by the dashed arrow, a first pressure sensor 6 is provided on the first inlet pipe 5 located upstream of the heat exchanger 1. The pressure of the first inlet pipe 5 is collected by the first pressure sensor 6, which is used to collect the pressure of the steam in the first inlet pipe 5.

[0082] According to another specific embodiment of the present invention, reference is made to Figure 1The steam waste heat recovery and utilization method of the present invention further includes: a second air inlet pipe 11 is provided between the condensate collection tank 4 and the first air inlet pipe 5; the upper part of the condensate collection tank 4 is connected to the first air inlet pipe 5 through the second air inlet pipe 11; a one-way valve and a second valve 12 are provided on the second air inlet pipe 11; the one-way valve allows steam to flow from the condensate collection tank 4 to the first air inlet pipe 5, preventing steam in the first air inlet pipe 5 from directly entering the condensate collection tank 4 without passing through the heat exchanger 1, causing a sudden increase in pressure in the condensate collection tank 4 and leading to a safety accident; the second valve 12 is used to control the opening and closing of the second air inlet pipe 11, such as... Figure 4 As shown, the steam waste heat recovery and utilization method also includes:

[0083] Collect the pressure of the steam above the condensate collection tank 4 (denoted as P2), and determine whether the pressure of the steam above the condensate collection tank 4 exceeds the pressure P1 of the first air inlet pipe 5 and the preset pressure P0.

[0084] If the steam pressure above the condensate collection tank 4 exceeds the pressure of the first air inlet pipe 5 and exceeds the preset pressure (i.e., P2 > P1 and P2 > P0), then the opening of the second valve 12 is increased; if the steam pressure above the condensate collection tank 4 does not exceed the pressure of the first air inlet pipe 5 and / or does not exceed the preset pressure, then the opening of the second valve 12 is decreased. Specifically, in this embodiment, considering the actual situation on site, decreasing the opening of the second valve 12 means reducing the opening of the second valve 12 to 0.

[0085] Using the above technical solution, when the pressure of the second pressure sensor 13 exceeds the pressure of the first pressure sensor 6 and also exceeds a preset pressure, the opening of the second valve 12 is increased to allow steam in the condensate collection tank 4 to be transported to the first air inlet pipe 5, thereby reducing the pressure in the condensate collection tank 4 and decreasing the probability of an explosion. When the pressure of the second pressure sensor 13 does not exceed the pressure of the first pressure sensor 6 and / or does not exceed the preset pressure, the control unit controls the opening of the second valve 12 to decrease to prevent excessive steam from entering the first air inlet pipe 5, which could cause excessive pressure in the first air inlet pipe 5 and pose a safety hazard.

[0086] According to another specific embodiment of the present invention, such as Figure 1 As shown, the steam waste heat recovery and utilization method of the present invention further includes: the condensate collection tank 4 is connected to the deaerator 3 through the second water inlet pipe 10 below, and the second water inlet pipe 10 is equipped with a pressure pump 15, which is used to transport the water in the second water inlet pipe 10 to the deaerator 3.

[0087] While the present invention has been illustrated and described with reference to certain preferred embodiments, those skilled in the art should understand that the above description is a further detailed explanation of the invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the invention to these descriptions. Various changes in form and detail can be made by those skilled in the art, including several simple deductions or substitutions, without departing from the spirit and scope of the invention.

Claims

1. A steam waste heat recovery and utilization system, characterized in that, include: The first air inlet pipe has an air inlet end connected to a steam source. The first air inlet pipe is equipped with a first pressure sensor, which is used to collect the pressure of the steam in the first air inlet pipe. The condensate collection tank is connected to the outlet end of the first air inlet pipe; The first water inlet pipe has its inlet end connected to a water source. The first water inlet pipe is equipped with a first water supply pump and a first valve. The first valve is used to regulate the opening and closing of the first water inlet pipe. The deaerator is connected to the outlet end of the first inlet pipe; The heat exchanger has the first air inlet pipe and the first water inlet pipe passing through it. The heat exchanger is used to exchange heat between the steam in the first air inlet pipe and the water in the first water inlet pipe, so as to raise the temperature of the water in the first water inlet pipe. A temperature sensor is installed on the first water inlet pipe, and the temperature sensor is located between the heat exchanger and the outlet end of the first water inlet pipe. The temperature sensor is used to collect the temperature of the water after heat exchange through the heat exchanger. The control unit is electrically connected to the first pressure sensor, the first valve, and the temperature sensor respectively. When the pressure collected by the first pressure sensor exceeds a preset pressure and / or the temperature collected by the temperature sensor exceeds a preset temperature, the control unit controls the opening of the first valve to increase. When the pressure collected by the first pressure sensor does not exceed the preset pressure and / or the temperature collected by the temperature sensor does not exceed the preset temperature, the control unit controls the opening of the first valve to decrease or maintains the opening of the first valve at the minimum opening.

2. The steam waste heat recovery and utilization system as described in claim 1, characterized in that, Also includes: The second air inlet pipe has an outlet end connected to the first air inlet pipe and an inlet end connected to the upper part of the condensate collection tank. The second air inlet pipe is equipped with a one-way valve and a second valve. The one-way valve allows steam in the second air inlet pipe to flow from the inlet end to the outlet end of the second air inlet pipe, and the second valve is used to control the opening and closing of the second air inlet pipe. A second pressure sensor is located on the upper part of the condensate collection tank. The second pressure sensor is used to collect the pressure of the steam at the upper part of the condensate collection tank. The control unit is also electrically connected to the second pressure sensor and the second valve; when the pressure of the second pressure sensor exceeds the pressure of the first pressure sensor and the pressure of the second pressure sensor exceeds the preset pressure, the control unit controls the opening of the second valve to increase; when the pressure of the second pressure sensor does not exceed the pressure of the first pressure sensor and / or the pressure of the second pressure sensor does not exceed the preset pressure, the control unit controls the opening of the second valve to decrease.

3. The steam waste heat recovery and utilization system as described in claim 1, characterized in that, Also includes: The deaerator is also equipped with a liquid level sensor, which is used to detect the actual liquid level in the deaerator. The control unit is also electrically connected to the liquid level sensor. When the actual liquid level in the deaerator exceeds the preset liquid level, the control unit controls the first valve to adjust to the minimum opening. When the actual liquid level in the deaerator does not exceed the preset liquid level, the control unit controls the opening of the first valve to increase.

4. A method for recovering and utilizing waste steam heat, used in the waste steam heat recovery and utilization system of claim 1, characterized in that, The method for recovering and utilizing waste steam heat includes: Collect the outlet water temperature of the heat exchanger and the pressure of the first air inlet pipe, and determine whether the outlet water temperature of the heat exchanger exceeds the preset temperature and whether the pressure of the first air inlet pipe exceeds the preset pressure. If the outlet water temperature of the heat exchanger exceeds the preset temperature, and / or the pressure of the first air inlet pipe exceeds the preset pressure, then the opening of the first valve is increased; If the outlet water temperature of the heat exchanger does not exceed the preset temperature, and / or the pressure of the first air inlet pipe does not exceed the preset pressure, then determine whether the opening degree of the first valve is greater than the minimum opening degree; If yes, then reduce the opening of the first valve to the minimum opening; if no, then keep the opening of the first valve unchanged.

5. The steam waste heat recovery and utilization method as described in claim 4, characterized in that, Before determining whether the outlet water temperature of the heat exchanger exceeds a preset temperature and whether the pressure of the first air inlet pipe exceeds a preset pressure, the method further includes: The actual liquid level of the deaerator is collected, and it is determined whether the actual liquid level of the deaerator exceeds the preset liquid level. If the actual liquid level in the deaerator exceeds the preset liquid level, the opening of the first valve is adjusted to the minimum opening. If the actual liquid level in the deaerator does not exceed the preset liquid level, the opening of the first valve is increased.

6. The steam waste heat recovery and utilization method as described in claim 5, characterized in that, The deaerator is equipped with a liquid level sensor, and the acquisition of the actual liquid level height of the deaerator includes: acquiring the actual liquid level height of the deaerator through the liquid level sensor.

7. The steam waste heat recovery and utilization method as described in claim 4, characterized in that, A temperature sensor is installed on the first inlet pipe downstream of the heat exchanger along the water flow direction. The acquisition of the outlet water temperature of the heat exchanger includes: acquiring the temperature of the water in the first inlet pipe through the temperature sensor.

8. The steam waste heat recovery and utilization method as described in claim 4, characterized in that, Along the flow direction of the steam, a first pressure sensor is provided on the first inlet pipe located upstream of the heat exchanger. The pressure of the first inlet pipe is collected by the first pressure sensor, which is used to collect the pressure of the steam in the first inlet pipe.

9. The steam waste heat recovery and utilization method as described in claim 4, characterized in that, A second air inlet pipe is provided between the condensate collection tank and the first air inlet pipe. The upper part of the condensate collection tank is connected to the first air inlet pipe through the second air inlet pipe. The second air inlet pipe is equipped with a one-way valve and a second valve. The one-way valve allows steam to flow from the condensate collection tank to the first air inlet pipe, and the second valve is used to control the opening and closing of the second air inlet pipe. The steam waste heat recovery and utilization method further includes: The pressure of the steam above the condensate collection tank is collected, and it is determined whether the pressure of the steam above the condensate collection tank exceeds the pressure of the first air inlet pipe and the preset pressure. If the pressure of the steam above the condensate collection tank exceeds the pressure of the first air inlet pipe and exceeds the preset pressure, the opening of the second valve is increased; if the pressure of the steam above the condensate collection tank does not exceed the pressure of the first air inlet pipe and / or does not exceed the preset pressure, the opening of the second valve is decreased.

10. The steam waste heat recovery and utilization method as described in claim 4, characterized in that, The condensate collection tank is connected to the deaerator via a second inlet pipe. A pressure pump is installed on the second inlet pipe to deliver water from the second inlet pipe to the deaerator.

11. The steam waste heat recovery and utilization method as described in claim 4, characterized in that, The minimum opening is 6%.

12. The steam waste heat recovery and utilization method as described in claim 5, characterized in that, The preset liquid level height is 1.1m.

13. The steam waste heat recovery and utilization method as described in claim 4, characterized in that, The preset temperature is 85°C.

14. The steam waste heat recovery and utilization method as described in claim 4 or 9, characterized in that, The preset pressure is 10000Pa.

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