An adaptive waste heat recovery device based on phase change heat accumulator

Abstract

The application relates to the technical field of steam exhaust recovery devices, and discloses a self-adaptive waste heat recovery device based on a phase change heat accumulator, which is provided with a heat medium inlet and a gas outlet on the side surface and is provided with a condensate outlet at the lower part; one tube pass unit comprises a collecting box which is divided into a first collecting cavity and a second collecting cavity by a partition plate, the first collecting cavity is connected with a refrigerant inlet pipe, and the second collecting cavity is connected with a refrigerant outlet pipe; a plurality of heat exchange pipes are arranged in the shell, and the heat exchange pipes comprise first heat exchange pipes and second heat exchange pipes. The application can continuously and stably output heating effect by introducing the phase change heat accumulator as a stable intermediate heat source. Even if the flow or temperature of the deaerator exhaust steam fluctuates, the heat accumulator can buffer and adjust through the heat storage and heat release process, effectively suppresses the sharp change of the downstream desalted water temperature, thereby guaranteeing the stability of the deaerator water working condition and improving the operation quality and efficiency of the whole thermal system.

Description

Technical Field

[0001] This invention relates to the field of exhaust steam recovery devices, specifically an adaptive waste heat recovery device based on a phase change heat storage body. Background Technology

[0002] In the field of thermal deaerator exhaust steam recovery technology, existing technologies have proposed various recovery devices to achieve energy reuse. The invention patent CN201410847036.3, entitled "Deaerator Exhaust Steam Energy Recovery Device and Energy Recovery Method Thereof," provides a typical solution. This device mainly consists of a cylinder, a water spray cooling chamber, an atomization space, heat and mass transfer components, and a steam distributor. Its working principle is to introduce demineralized water and deaerator exhaust steam for mass and heat transfer within the device. Non-condensable gases are separated and discharged from the top, and condensate and atomized liquid film are recovered together. This type of technology integrates multiple heat and mass transfer methods such as atomization, water spray pan, and liquid film to improve efficiency and also has heat absorption and non-condensable gas desorption functions.

[0003] Despite some progress in existing technologies, several significant shortcomings remain. First, there is still room for improvement in heat and mass transfer efficiency. The integrated "atomization, water distribution tray, and liquid film" method described in patent CN201410847036.3 may, in actual operation, result in insufficient contact between steam and the cooling medium due to uneven liquid film renewal or poor atomization, thus affecting condensation efficiency. Second, existing waste heat recovery devices, with their fixed structures and lack of adaptive adjustment capabilities, struggle to cope with the load and parameter fluctuations commonly encountered in deaerator operation. These existing solutions fail to fundamentally address the key challenges of efficient, stable, and adaptive operation. Summary of the Invention

[0004] In view of the shortcomings of existing waste heat recovery devices mentioned in the background art, the present invention provides an adaptive waste heat recovery device based on phase change heat storage, which has the advantages of small temperature fluctuation and self-adjustment, and solves the technical problems mentioned in the background art.

[0005] This invention provides the following technical solution: an adaptive waste heat recovery device based on a phase change heat storage body, comprising a shell with a heat medium inlet and a gas outlet on its side and a condensate outlet at the bottom; a tube-side unit including a collection box divided into a first collection chamber and a second collection chamber by a partition, the first collection chamber being connected to a refrigerant inlet pipe and the second collection chamber being connected to a refrigerant outlet pipe; multiple heat exchange tubes disposed within the shell, the heat exchange tubes including a first heat exchange tube and a second heat exchange tube, the top ends of the first heat exchange tube and the second heat exchange tube respectively communicating with the first collection chamber and the second collection chamber, and the bottom ends of the first heat exchange tube and the second heat exchange tube being connected; the shell is filled with a solid phase heat storage material, and the multiple heat exchange tubes are embedded and immersed in the solid phase heat storage material to form a heat storage chamber; the device further includes a zone adjustment mechanism, which is configured to dynamically change the ratio of the number of the first heat exchange tube communicating with the first collection chamber and the number of the second heat exchange tube communicating with the second collection chamber in response to the fluid temperature difference between the first collection chamber and the second collection chamber.

[0006] Preferably, the solid-phase heat storage material is a phase change material, and its phase change temperature is between the refrigerant inlet temperature and the steam temperature of the heat medium inlet.

[0007] Preferably, the phase change material is one or more of the following: molten salt, hydrated crystalline salt, or paraffin.

[0008] Preferably, the partition adjustment mechanism includes: a temperature-sensing air chamber disposed in the partition, with its two ends located in the first and second flow collection chambers respectively, and an active slider disposed in the temperature-sensing air chamber that can move according to the pressure difference between the two air chambers; and a movable adjustment sealing plate that is slidably disposed at the bottom of the first and second flow collection chambers for increasing or decreasing the proportion of the number of interfaces connecting the heat exchange tubes; wherein, the active slider and the movable adjustment sealing plate are connected by magnetic coupling or mechanical linkage, so that the movement of the active slider can drive the movable adjustment sealing plate to move synchronously.

[0009] Preferably, the heat exchange tubes are uniformly distributed in a spiral or serpentine coil shape within the solid-phase heat storage material.

[0010] Preferably, the device further includes a sedimentation section connected to the bottom end of the heat exchange tube for sedimenting and separating impurities in the refrigerant, and the bottom of the sedimentation section is provided with a drain pipe with a constant pressure opening valve.

[0011] Preferably, regulating valves are provided at the heat medium inlet and the gas outlet. The regulating valves are signal-connected to the zone regulating mechanism and can synchronously adjust their opening degree according to the change of fluid temperature difference.

[0012] The present invention has the following beneficial effects:

[0013] 1. This invention introduces a phase change heat storage medium as a stable intermediate heat source, enabling the device to output a continuous and stable heating effect. Even if the flow rate or temperature of the deaerator exhaust steam fluctuates, the heat storage medium can buffer and regulate through its own heat storage and release processes, effectively suppressing drastic changes in the downstream demineralized water temperature, thereby ensuring the stability of the deaerator influent conditions and improving the operating quality and efficiency of the entire thermal system.

[0014] 2. This invention utilizes an adaptive zoned adjustment mechanism comprised of an inlet / outlet water temperature difference detection device and a movable adjusting seal plate. This mechanism enables the device to intelligently maintain the condensate level within the heat exchange section at the optimal range. It automatically adjusts the effective heat exchange area and steam flux based on real-time heat load, fundamentally avoiding the decrease in condensation efficiency caused by excessively high liquid levels and the risk of pump cavitation caused by excessively low liquid levels, thus achieving fully automatic, safe, and efficient system operation.

[0015] 3. This invention replaces the direct heat exchange between steam and demineralized water with indirect heat exchange through a heat storage medium. This avoids direct and violent impact between high-temperature steam and the low-temperature pipe wall, while ensuring that the heat exchange tubes are always in a uniform and mild thermal field created by the heat storage material. This not only significantly reduces the risk of damage to the heat exchange tubes due to thermal stress fatigue and extends the equipment's lifespan, but the resulting pressure changes trigger the automatic drainage function of the drain pipe, further ensuring the long-term cleanliness and stability of the system. Attached Figure Description

[0016] Figure 1 A schematic diagram of the overall structure of the invention;

[0017] Figure 2 For the present invention Figure 1 Enlarged view of a portion of the structure at point A;

[0018] Figure 3 This is a schematic diagram of the first cross-section of the spiral structure of the present invention;

[0019] Figure 4 This is a schematic diagram of the second cross-section of the spiral structure of the present invention.

[0020] In the diagram: 1. Manifold; 111. Refrigerant inlet pipe; 112. Refrigerant outlet pipe; 12. Baffle plate; 121. First manifold chamber; 122. Second manifold chamber; 13. Temperature sensing chamber; 131. Active slider; 14. Adjustment sealing plate; 2. Shell; 211. Heat medium inlet; 212. Condensate outlet; 213. Gas outlet; 221. First heat exchange tube; 222. Second heat exchange tube; 3. Sedimentation section; 31. Drain pipe; 4. Solid phase heat storage material. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Please see Figure 1An adaptive waste heat recovery device based on a phase change heat storage medium includes a recovery tower, which consists of a collector box 1, a shell 2, and a sedimentation section 3. The shell 2 is filled with solid phase heat storage material 4 for heat exchange and heat recovery. The sedimentation section 3 is used to precipitate and separate impurities in the refrigerant. A support is provided at the bottom of the recovery tower to support the tower body. A partition 12 is fixedly installed in the middle of the collector box 1, dividing the interior of the collector box 1 into two independent left and right chambers. The left chamber is designated as the first collector chamber 121, and the right chamber is designated as the second collector chamber 122. A refrigerant inlet pipe 111 communicating with the first collector chamber 121 and a refrigerant outlet pipe 112 communicating with the second collector chamber 122 are provided on the outer wall of the recovery tower. Several heat exchange tube interfaces are evenly provided on the bottom surface of the second collection cavity 122 and 21, and heat exchange tubes are fixedly connected through the interfaces. The heat exchange tubes are set inside the shell 2, and the other end is connected to the sedimentation section 3. The temperature at the first heat exchange tube 221 is lower than the temperature at the second heat exchange tube 222, forming a high temperature difference heat exchange zone, while the second heat exchange tube 222 forms a low temperature difference heat exchange zone. A heat medium inlet 211 is provided on one side of the lower part of the shell 2. The heat medium inlet 211 is connected to the heat medium. After the heat medium enters the shell 2, it undergoes full heat exchange with the first heat exchange tube 221 and the second heat exchange tube 222. The generated condensate flows down its outer wall to the bottom of the shell 2. A condensate outlet 212 is provided on the other side of the lower part of the shell 2. The condensate is discharged from here and transported to the condensate tank. The top of the shell 2 has a A gas outlet 213 is provided on the side for discharging gas. A temperature-sensing chamber 13 is fixedly installed at the partition 12 to detect the temperature difference of the refrigerant in the first and second manifolds 121 in real time. A movable sealing rail is fixedly installed at the bottom of the temperature-sensing chamber 13, and a movable adjusting sealing plate 14 is movably connected in the middle of the movable sealing rail. The movable adjusting sealing plate 14 moves according to the temperature detection and control of the temperature-sensing chamber 13, adjusting the ratio of the number of heat exchange tube interfaces at the bottom of the first and second manifolds 121 and 122. This allows the number of heat exchange tubes covered by the first and second manifolds 121 and 122 to be adjusted according to the temperature difference, thereby adjusting the ratio of the number of first and second heat exchange tubes 221 to 222. Simultaneously, it monitors the temperature difference in real time with the temperature-sensing chamber 13. The opening of the heat medium inlet 211 and the gas outlet 213 is adjusted to ensure that the condensate level inside the shell 2 remains within the normal height range. When the opening of the heat medium inlet 211 is too large, too much steam enters the shell 2 for heat exchange, resulting in a large amount of condensate accumulating at the bottom of the shell 2 and being difficult to discharge through the condensate outlet 212 in time. At this time, the temperature rise generated by the heat exchange between the first heat exchange tube 221 and the second heat exchange tube 222 is large. After the temperature sensing chamber 13 detects the high temperature difference between the first collector cavity 121 and the second collector cavity 122, it reduces the opening of the heat medium inlet 211 and the gas outlet 213 to enable low discharge operation to avoid abnormal condensation due to excessively high liquid level inside the shell 2. At the same time, the temperature sensing chamber 13 adjusts the movable regulating plate 14 to move along the regulating plate moving rail.This reduces the number of first heat exchange tubes 221 connected to the bottom of the first collector cavity 121 and increases the number of second heat exchange tubes 222 connected to the bottom of the second collector cavity 122, thereby reducing the volume of the high-temperature differential heat exchange zone and increasing the volume of the low-temperature differential heat exchange zone. This is to adapt to the low-discharge ventilation condensation efficiency and further reduce the condensation rate to achieve the effect of rapid discharge of condensate accumulated in the shell 2. However, when the condensation efficiency in the shell 2 is too low and the condensate level in the shell 2 is too low, which can easily cause water pump cavitation, the low heat exchange efficiency reduces the temperature difference between the first collector cavity 121 and the second collector cavity 122, and the temperature sensing chamber 13... The opening of the heat transfer medium inlet 211 and gas outlet 213 is increased by adjusting the low temperature difference. Simultaneously, the movable regulating plate 14 moves along the regulating plate track, increasing the number of first heat exchange tubes 221 connected to the bottom of the first collecting cavity 121 and decreasing the number of second heat exchange tubes 222 connected to the bottom of the second collecting cavity 122. This increases the volume of the high temperature difference heat exchange zone and decreases the volume of the low temperature difference heat exchange zone, significantly improving thermal efficiency. This rapidly increases the condensation efficiency, quickly accumulating condensate in the shell 2 and raising the liquid level inside the shell 2 to avoid pump cavitation caused by low liquid level exposure.

[0023] Please see Figure 2 The temperature-sensing chamber 13 is a chamber that passes through both ends of the partition 12 and is connected to the first collection chamber 121 and the second collection chamber 122 respectively. An active slider 131 is movably connected in the middle of the temperature-sensing chamber 13. The active slider 131 divides the temperature-sensing chamber 13 into two parts. The gas in the two chambers undergoes different volume changes depending on the temperature difference between the first collection chamber 121 and the second collection chamber 122, thereby pushing the active slider 131 to move left and right along the chamber. When the temperature difference between the two ends is large, the active slider 131 moves towards the first collection chamber 121. On one side, when the temperature difference between the two ends is small, the active slider 131 moves towards the second collector cavity 122. The bottom surface of the active slider 131 is magnetic, and the top of the movable adjustment sealing plate 14 is magnetic with opposite polarity. This allows the movable adjustment sealing plate 14 to adjust its position in real time as the active slider 131 moves, so that the movable adjustment sealing plate 14 moves smoothly with the linear change of the temperature difference between the first collector cavity 121 and the second collector cavity 122, thereby achieving smooth adjustment between the high temperature difference heat exchange zone and the low temperature difference heat exchange zone.

[0024] Please see Figure 3 The first heat exchange tube 221 and the second heat exchange tube 222 are spirally arranged inside the shell 2, so that the high temperature difference heat exchange zone and the low temperature difference heat exchange zone are evenly distributed in a spiral shape inside the shell 2, thereby ensuring that the heat exchange efficiency is uniform throughout the shell 2 and avoiding the problem of insufficient condensation on one side caused by the steam introduced from the heat medium inlet 211 flowing on one side, thus making the condensation effect inside the shell 2 better.

[0025] Please see Figure 4A constant pressure valve is installed at the drain pipe 31. When the volume of the low temperature differential heat exchange zone is greater than that of the high temperature differential heat exchange zone, that is, when the number of the second heat exchange tubes 222 is greater than that of the first heat exchange tubes 221, the amount of demineralized water entering the sedimentation section 3 is lower than the amount discharged, and the water pressure in the sedimentation section 3 is low, resulting in normal sedimentation. However, when the volume of the low temperature differential heat exchange zone is smaller than that of the high temperature differential heat exchange zone, that is, when the number of the first heat exchange tubes 221 is greater than that of the first heat exchange tubes 221, the amount of refrigerant entering the sedimentation section 3 is greater than the amount discharged, and the pressure increases. When the pressure in the sedimentation section 3 rises to the opening pressure of the constant pressure valve at the drain pipe 31, the valve opens, and the impurities settled at the bottom of the sedimentation section 3 are automatically discharged from the drain pipe 31 under pressure until the pressure drops, at which point the valve at the drain pipe 31 closes automatically, thereby achieving the effect of periodically and automatically discharging impurities from the sedimentation section 3.

[0026] The working principle of the method of using this invention is as follows:

[0027] In operation, high-temperature steam discharged from the thermal deaerator enters the internal space of the shell 2 through the heat transfer medium inlet 211. At this time, the high-temperature steam does not directly contact the heat exchange tubes, but rather exchanges heat fully with the solid-phase heat storage material 4, especially the phase change material, filled within the shell. The latent heat of vaporization carried by the steam is absorbed by the heat storage material, causing the steam to condense into water. The condensate accumulates at the bottom of the shell 2 and is discharged through the condensate outlet 212, being recovered into the system. Non-condensable gases such as oxygen are discharged from the gas outlet 213 at the top. During this process, the temperature of the heat storage material rises; if a phase change material is used, it will undergo a phase change, melting from a solid to a liquid state, storing a large amount of thermal energy.

[0028] Meanwhile, the cold demineralized water to be heated enters the first collection chamber 121 through the refrigerant inlet pipe 111, and is then distributed to the first heat exchange tube 221 connected to this chamber. The first heat exchange tube 221 is immersed in the heated heat storage material. As the cold demineralized water flows through the first heat exchange tube 221, it absorbs heat from the surrounding heat storage material 4, and its temperature rises significantly. Subsequently, the heated fluid is collected in the second collection chamber 122 through the second heat exchange tube 222, and finally output through the refrigerant outlet pipe 112 to equipment requiring hot water, such as deaerators, thereby realizing energy recovery and utilization.

[0029] The temperature-sensing chamber 13 of the inlet and outlet water temperature difference detection device passes through the partition 12. The inlet temperature-sensing chamber and the outlet temperature-sensing chamber at both ends of the device sense the temperature of the first collector chamber 121 and the second collector chamber 122, respectively.

[0030] When the heat load is too high, the temperature difference between the inlet and outlet water becomes too large: the heat release rate of the solid-phase heat storage material 4 is too fast, which may cause its temperature to drop too quickly. At this time, the gas in the inlet water temperature sensing chamber expands more significantly due to heat, pushing the active slider 131 to move towards the first collection chamber 121. Through magnetic coupling, the movable adjustment sealing plate 14 moves in the same direction, reducing the number of first heat exchange tubes 221 participating in heat exchange, while relatively increasing the number of second heat exchange tubes 222. This is equivalent to shrinking the efficient "high temperature difference heat absorption zone" and expanding the inefficient "low temperature difference heat absorption zone", thereby reducing the overall heat absorption rate and preventing the solid-phase heat storage material 4 from being cooled too quickly. At the same time, the system will reduce the opening of the heat medium inlet 211 and the gas outlet 213 to reduce the amount of steam entering, reducing the load from the source.

[0031] When the heat load is insufficient, the temperature difference between the inlet and outlet water is too small: the heat release rate of the solid-phase heat storage material 4 is too slow, and its own temperature may be too high. At this time, the active slider 131 moves towards the second collection chamber 122 under the action of the pressure difference between the two air chambers, driving the movable regulating seal plate 14 to move in the opposite direction, which increases the number of the first heat exchange tubes 221 and decreases the number of the second heat exchange tubes 222. This expands the "high temperature difference heat absorption zone", improves the overall heat absorption efficiency, accelerates the extraction of heat from the solid-phase heat storage material 4, and causes its temperature to drop back to the normal operating range. At the same time, the opening of the steam inlet valve increases to introduce more heat source.

[0032] The heated demineralized water enters the sedimentation section 3 through the first heat exchange tube 221 for sedimentation. When the device is in high heat absorption efficiency mode, i.e., the number of first heat exchange tubes 221 is much greater than the number of second heat exchange tubes 222, the amount of water flowing into the sedimentation section 3 will be greater than the amount flowing out, causing the internal pressure to rise. When the pressure reaches the set pressure of the constant pressure valve on the drain pipe 31, the valve automatically opens, quickly discharging the impurities and wastewater settled at the bottom. After the pressure returns to normal, the valve automatically closes, achieving periodic automatic cleaning.

[0033] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0034] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An adaptive waste heat recovery device based on a phase change heat storage body, comprising a shell (2) with a heat medium inlet (211) and a gas outlet (213) on its side and a condensate outlet (212) at its bottom; a tube-side unit including a collector box (1) divided into a first collector chamber (121) and a second collector chamber (122) by a partition (12), wherein the first collector chamber (121) is connected to a refrigerant inlet pipe (111) and the second collector chamber (122) is connected to a refrigerant outlet pipe (112); multiple heat exchange tubes disposed in the shell (2), wherein the heat exchange tubes include a first heat exchange tube (221) and a second heat exchange tube (222), wherein the top ends of the first heat exchange tube (221) and the second heat exchange tube (222) are respectively connected to the first collector chamber (121) and the second collector chamber (122), and the bottom ends of the first heat exchange tube (221) and the second heat exchange tube (222) are connected; characterized in that: The shell (2) is filled with solid phase heat storage material (4), and the multiple first heat exchange tubes (221) and second heat exchange tubes (222) are embedded and immersed in the solid phase heat storage material (4) to form a heat storage chamber; the device also includes a partition adjustment mechanism, which is configured to dynamically change the ratio of the number of the first heat exchange tubes (221) connected to the first heat exchange tube (121) and the number of the second heat exchange tubes (222) connected to the second heat exchange tube (122) in response to the fluid temperature difference between the first heat exchange tube (121) and the second heat exchange tube (222) connected to the second heat exchange tube (122); The partition adjustment mechanism includes: a temperature-sensing air chamber (13) disposed in the partition (12), with its two ends located in the first collection chamber (121) and the second collection chamber (122) respectively, and an active slider (131) disposed in the temperature-sensing air chamber (13) that can move according to the pressure difference between the two air chambers; and a movable adjustment sealing plate (14) which is slidably disposed at the bottom of the first collection chamber (121) and the second collection chamber (122) for increasing or decreasing the ratio of the number of interfaces connecting the first heat exchange tube (221) and the second heat exchange tube (222); wherein, the active slider (131) and the movable adjustment sealing plate (14) are connected by magnetic coupling or mechanical linkage, so that the movement of the active slider (131) can drive the movable adjustment sealing plate (14) to move synchronously; The heat medium inlet (211) and gas outlet (213) are equipped with regulating valves. The regulating valves are signal-connected to the partition regulating mechanism and can adjust their opening degree synchronously with the change of fluid temperature difference.

2. The adaptive waste heat recovery device based on a phase change thermal storage body according to claim 1, characterized in that: The solid-phase heat storage material (4) is a phase change material, and its phase change temperature is between the refrigerant inlet temperature and the steam temperature of the heat medium inlet.

3. The adaptive waste heat recovery device based on a phase change thermal storage body according to claim 2, characterized in that: The phase change material is one or more of the following: molten salt, hydrated crystalline salt, or paraffin.

4. The adaptive waste heat recovery device based on a phase change thermal storage body according to claim 1, characterized in that: The first heat exchange tube (221) and the second heat exchange tube (222) are uniformly distributed in the solid phase heat storage material (4) in a spiral or serpentine coil shape.

5. The adaptive waste heat recovery device based on a phase change thermal storage body according to claim 1, characterized in that: The device also includes a sedimentation section (3) connected to the bottom of the first heat exchange tube (221) and the second heat exchange tube (222) for sedimentation and separation of impurities in the refrigerant. The bottom of the sedimentation section (3) is provided with a drain pipe (31) with a constant pressure opening valve.

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