A block hole type high temperature corrosion resistant graded phase change heat storage heat exchanger

Abstract

The present invention relates to the field of heat exchange technology, and in particular to a block-hole, high-temperature, corrosion-resistant, graded phase-change heat storage heat exchanger. The heat exchanger comprises a housing and a multi-stage heat exchange section disposed within the housing. The housing is provided with an HTF inlet and an HTF outlet. The multi-stage heat exchange section is formed by splicing together a plurality of heat storage units, each of which stores PCM. The heat storage units are provided with a plurality of storage tanks for admitting PCM. A plurality of flow channels for admitting HTF are provided on both sides of the storage tanks. The plurality of flow channels are spliced ​​together to form a channel for guiding the flow of HTF. The present invention stacks the heat storage units in sequence to form a multi-section heat exchange section, which has a wide range of applications. The stacking form can prevent the PCM from expanding and overflowing after being heated. The heat storage unit has the advantages of high heat exchange efficiency, simple structure, and easy assembly and disassembly.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchangers, and in particular to a block hole type high temperature corrosion resistant graded phase change heat storage heat exchanger. Background Art

[0002] A heat exchanger is a device that transfers part of the heat of a hot fluid to a cold fluid, also known as a heat exchanger. The current mainstream phase change heat accumulators are: packed bed type and plate type. Among them, the packed bed type heat accumulator has an outer wall made of thin film material and wraps the PCM inside it. The heat storage unit is small in size and large in specific surface area. It is placed in the packed bed by stacking fillers. HTF flows through the packed bed. Due to the small size and large number of heat storage units, HTF easily forms a turbulent state, which enhances the heat transfer efficiency. However, the cost of manufacturing the capsule is high, and the complex internal turbulence and strong nonlinear phase change will bring great resistance, so it is only suitable for small-scale heat storage environments. Among them, the plate type heat accumulator has the advantages of high heat transfer coefficient, compact structure and low heat loss, but is mainly limited by the sealing material's poor sealing due to its lack of high temperature resistance and difficulty in long-term corrosion resistance, as well as the problem of easy clogging and difficulty in cleaning caused by the structure itself.

[0003] Chinese patent CN106959032A discloses a high-temperature molten salt phase-change heat storage and release device. The device comprises at least: a heat accumulator with a gas inlet and outlet; and a heat storage tube array comprising multiple heat storage tubes installed within the heat accumulator. The heat storage tubes are filled with a high-temperature phase-change material with a freezing point above 750°C, which exchanges heat with the gas entering the heat accumulator. During the day, the high-temperature gas flows through the heat accumulator, exchanges heat with the phase-change material within the heat storage tubes, storing energy within the heat storage tubes. After the heat exchange, the gas temperature drops to low-temperature gas, which then returns to the heat collector / concentrator tower to absorb heat. At night, the low-temperature gas flows through the heat accumulator, absorbs heat, and then flows to the power generation system to generate power. The phase-change material in the heat accumulator cools down after the heat exchange. This heat storage and release device raises the medium temperature of the power generation system, thereby improving the system's power generation efficiency. It is compact and economical.

[0004] However, this technical solution will cause dirt to accumulate in the heat storage tube after long-term use, which is inconvenient to clean, resulting in reduced heat exchange efficiency. In addition, the heat exchange tube is not suitable for certain special fluid media or complex working conditions, and has great limitations. Summary of the Invention

[0005] The present invention addresses the shortcomings of the prior art by providing a block-type, high-temperature, corrosion-resistant, graded phase-change heat storage heat exchanger. Multiple heat storage units are stacked and spliced ​​into multiple heat exchange sections. PCM stored within the heat storage units is combined with graded proportions of PCM with different phase change temperatures to adapt to the temperature gradient formed by heat transfer in the heat storage tube (HTF). This allows for full utilization of the latent heat of the PCM, ensuring the heat exchange efficiency of the heat exchanger. Furthermore, the spliced ​​heat storage units facilitate disassembly and cleaning when necessary, reducing cleaning difficulty and resolving the prior art issue of inconvenient heat storage tube cleaning.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A block-hole, high-temperature, corrosion-resistant, graded phase-change heat storage heat exchanger comprises: a housing and a multi-stage heat exchange section disposed within the housing. The housing is provided with an HTF inlet and an HTF outlet. The multi-stage heat exchange section is formed by splicing together a plurality of heat storage units, each of which stores PCM. The heat storage units are provided with a plurality of storage tanks for receiving PCM. A plurality of flow channels for receiving HTF are provided on both sides of the storage tanks. The plurality of flow channels are spliced ​​together to form a channel for guiding the flow of HTF.

[0008] Preferably, the phase change temperature of the PCM in the multi-stage heat exchange zone decreases gradually from top to bottom.

[0009] Preferably, the periphery of the multi-stage heat exchange zone is coated with a thermal insulation material.

[0010] Preferably, the multi-stage heat exchange interval is fixed in the shell through a steel frame.

[0011] Preferably, a gap is left between the steel frame and the shell.

[0012] Preferably, guide plates are provided on two adjacent multi-stage heat exchange intervals.

[0013] Preferably, a plurality of edge holes which can be stacked and assembled to form the flow channel are provided on both sides of the heat storage unit.

[0014] Preferably, one end of the storage tank passes through the heat storage unit, while the other end does not pass through the heat storage unit.

[0015] Preferably, the heat storage unit is made of graphite material, and both the inner and outer surfaces thereof are coated with a dense coating.

[0016] The beneficial effects of the present invention are:

[0017] (1) The present invention divides the multi-section heat exchange area into three heat exchange zones, which are: high temperature zone, medium temperature zone and low temperature zone from top to bottom. The heat storage units are stacked in sequence. The stacking form can avoid the expansion and overflow of PCM after heating, and can also achieve close fit without damaging the coating, thereby greatly reducing the direct contact between PCM and HTF, thereby ensuring heat exchange efficiency. At the same time, the stacked structure of the heat storage unit improves the convenience of cleaning.

[0018] (2) The present invention can reduce the short-flow escape of HTF by arranging the block hole type heat storage unit in the heat accumulator, uniformly control the flow rate and flow direction of HTF fluid, and adjust the flow field of HTF and increase the heat exchange area by changing the stacking size and the flow channel opening, thereby reducing resistance and improving heat exchange efficiency.

[0019] (3) The present invention can greatly reduce the energy loss in the heat storage process by coating the outer periphery of the multi-stage heat exchange zone with insulation materials, specifically using flexible non-metallic insulation materials such as graphite fiber, aluminum silicate fiber, etc., and then coating the stacked heat storage units.

[0020] (4) The present invention leaves a gap between the steel frame and the outer shell so as to leave space for releasing the thermal expansion after the internal heating, thereby eliminating the adverse effects caused by thermal stress.

[0021] (5) The present invention provides guide plates in the multi-stage heat exchange interval to ensure that HTF flows smoothly and quickly flows down the channel between the shell and the heat storage unit without backflow or splashing, thereby ensuring heat exchange efficiency.

[0022] (6) The present invention uses a continuous HTF flow channel and a heat storage unit made of graphite material to achieve heat exchange of media in complex working conditions, such as melts with high viscosity, melts containing particles, and highly corrosive fluids. In addition, the arrangement of PCM and HTF flow channels is combined to achieve efficient heat exchange, and multi-stage heat exchange zones are used to achieve full energy utilization.

[0023] In summary, the present invention stacks the thermal storage units in sequence to form multiple heat exchange sections, which has a wide range of applications. The stacking form can prevent the PCM from expanding and overflowing after being heated. It has the advantages of high heat exchange efficiency, simple structure, and easy assembly and disassembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A cross-sectional view of the present invention taken along the storage tank;

[0025] Figure 2 It is a cross-sectional view of the present invention cut along the flow channel;

[0026] Figure 3A sectional view of the present invention taken along the cross section of the flow channel;

[0027] Figure 4 for Figure 3 A magnified view of point A;

[0028] Figure 5 Schematic diagram of the structure of the heat storage unit of the present invention. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and 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, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0031] Example

[0032] like Figure 1-Figure 5As shown, this embodiment provides a block hole type high temperature corrosion resistant graded phase change heat storage heat exchanger, comprising: a shell 1 and a multi-stage heat exchange section 2 arranged inside the shell 1, the shell is provided with an HTF inlet 11 and an HTF outlet 12, the multi-stage heat exchange section 2 is formed by splicing a plurality of heat storage units 21, the heat storage unit 21 stores PCM inside, and the PCM absorbs and releases latent heat through phase change, thereby improving the heat exchange efficiency; the heat storage unit 21 is provided with a plurality of storage cells for passing the PCM. A plurality of flow channels 211 for introducing HTF are provided on both sides of the storage tank 212. The flow channels 211 are connected to form a channel for guiding the flow of HTF. The block-shaped thermal storage units 21 are arranged in the thermal accumulator to reduce the short-circuit escape of HTF and uniformly control the flow rate and direction of HTF fluid. By adjusting the number of stacked thermal storage units 21 and the size of the openings in the flow channels 211, the flow field of HTF can be adjusted, the heat exchange area can be increased, the resistance can be reduced, and the heat exchange efficiency can be improved.

[0033] Among them, the heat storage unit 21 is preferably rectangular for easy stacking. Generally, there are two types of stacking: horizontal stacking and vertical stacking, that is, the block hole is rectangular, and the block hole can also be made into other shapes such as circular block holes to adapt to different working environments.

[0034] At the same time, the heat storage units 21 within the multi-stage heat exchange section 2 are installed in a longitudinally stacked manner. The HTF inlet 11 and the HTF outlet 12 are respectively arranged at the upper and lower ends of the shell 1. The HTF flows in an overall S-shaped direction between the shell 1 and the heat storage unit 21 to ensure heat exchange efficiency. The HTF inlet 11 and the HTF outlet 12 can be installed with HTF fluid interfaces and instrument interfaces such as temperature and pressure measurement interfaces.

[0035] In the present invention, the outer shell 1 has multiple concave portions, which divide the multi-stage heat exchange zone 2 into multiple heat exchange zones. Specifically, since the temperature of HTF changes with the heat exchange of PCM from entering the heat exchanger to flowing out of the heat exchanger, the PCM in the unitary block-type thermal storage unit 21 can be set with different formulations according to the temperature gradient, and the phase change temperature of the PCM can be graded to ensure that the latent heat of the PCM can be utilized at each temperature gradient, thereby achieving the optimal heat storage or heat release effect.

[0036] Preferably, the phase change temperature of the PCM in the multi-stage heat exchange zone 2 gradually decreases from top to bottom. Specifically, it is preferably divided into three heat exchange zones, which are, from top to bottom, a high-temperature zone, a medium-temperature zone, and a low-temperature zone. The HTF inlet 11 is arranged in the high-temperature zone, and the HTF outlet 12 is arranged in the low-temperature zone. By grading and proportioning PCMs with different phase change temperatures, the temperature gradient formed by the HTF due to heat exchange can be adapted, thereby fully utilizing the latent heat of the PCM.

[0037] In the present invention, the stacking form can prevent the PCM from expanding and overflowing after being heated, and can also achieve close fit without damaging the coating, thereby greatly reducing the direct contact between the PCM and the HTF.

[0038] In the present invention, the periphery of the multi-stage heat exchange zone 2 is coated with insulation material, specifically flexible non-metallic insulation material such as graphite fiber, aluminum silicate fiber, etc., and then the stacked heat storage unit 21 is coated, which can greatly reduce the energy loss during the heat storage process.

[0039] In the present invention, the multi-stage heat exchange section 2 is fixed in the shell 1 by a steel frame 13, and the steel frame 13 can fix the structural stability of the thermal insulation material.

[0040] In the present invention, a gap 14 is left between the steel frame 13 and the shell 1 so as to leave space for releasing the thermal expansion after internal heating and eliminating the adverse effects of thermal stress. At the same time, the gap 14 can also be filled with flexible insulation material or sealing material.

[0041] In the present invention, a guide plate 22 is provided on the multi-stage heat exchange section 2 to ensure that the HTF flows smoothly and quickly flows down the channel between the shell 1 and the heat storage unit 21 without backflow or splashing, thereby ensuring heat exchange efficiency.

[0042] In the present invention, the storage tank 212 and the flow channel 211 are not interconnected and do not interfere with each other, so as to ensure the normal progress of the heat exchange process.

[0043] In the present invention, a plurality of edge holes 213 are provided on both sides of the heat storage unit 21 and can be stacked and assembled into the flow channel 211 , preferably in a semicircular through-shape for easy stacking operation.

[0044] In the present invention, the flow channel 211 is preferably circular, which is convenient for longitudinal stacking, simple operation, and easy disassembly and assembly. It can also be made into other forms such as rectangle to ensure its scope of application.

[0045] In the present invention, one end of the storage tank 212 passes through the thermal storage unit 21, and the other end does not pass through the thermal storage unit 21. Specifically, a plurality of storage tanks 212 are opened on the top of the thermal storage unit 21. The storage tanks 212 do not pass through the bottom and are in a semi-open, not completely closed state for storing PCM.

[0046] In the present invention, the heat accumulator as a whole can be made into a cylindrical shape.

[0047] Of course, the heat storage unit 21 is made of graphite material, and its inner and outer surfaces are coated with a dense coating, so that the surface of the heat storage unit 21 is smooth, the structure is simple, and it is not easy to scale. The form of graphite plus dense coating can enable the heat accumulator to be used in more severe environments, including the corrosiveness of PCM, the corrosiveness of HTF, a higher heat storage temperature range, and melts with poor fluidity or melt materials containing particles, all of which can meet normal production requirements.

[0048] In addition, dense coatings can be made of ceramic coatings or silicon carbide coatings, and can also be made of other organic materials such as resin coatings, or inorganic materials such as tantalum carbide coatings, making graphite a high-temperature resistant, corrosion-resistant and impermeable material.

[0049] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A block hole type high temperature corrosion resistant graded phase change heat storage heat exchanger, characterized in that: The heat exchanger comprises a housing and a multi-stage heat exchange section disposed within the housing. The housing is provided with an HTF inlet and an HTF outlet. The multi-stage heat exchange section is formed by splicing together a plurality of heat storage units, each of which stores PCM. The heat storage units are provided with a plurality of storage tanks for receiving PCM. A plurality of flow channels for receiving HTF are provided on both sides of the storage tanks. The plurality of flow channels are spliced ​​together to form a channel for guiding the flow of HTF. A plurality of edge holes are provided on both sides of the heat storage unit and can be stacked and assembled to form the flow channel; One end of the storage tank passes through the heat storage unit, and the other end does not pass through the heat storage unit.

2. The block hole type high temperature corrosion resistant graded phase change heat storage heat exchanger according to claim 1, characterized in that: The phase change temperature of the PCM in the multi-stage heat exchange zone gradually decreases from top to bottom.

3. The block hole type high temperature corrosion resistant graded phase change heat storage heat exchanger according to claim 1, characterized in that: The outer periphery of the multi-stage heat exchange zone is coated with a thermal insulation material.

4. The block hole type high temperature corrosion resistant graded phase change heat storage heat exchanger according to claim 1, characterized in that: The multi-stage heat exchange interval is fixed in the shell through a steel frame.

5. The block hole type high temperature corrosion resistant graded phase change heat storage heat exchanger according to claim 4, characterized in that: A gap is left between the steel frame and the shell.

6. The block hole type high temperature corrosion resistant graded phase change heat storage heat exchanger according to claim 1, characterized in that: Two adjacent multi-stage heat exchange intervals are provided with guide plates.

7. The block hole type high temperature corrosion resistant graded phase change heat storage heat exchanger according to claim 1, characterized in that: The heat storage unit is made of graphite material, and both the inner and outer surfaces thereof are coated with a dense coating.

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