Block hole type high-temperature corrosion-resistant graded phase change heat storage heat exchanger

Abstract

The invention relates to the technical field of heat exchange of heat exchangers, in particular to a block hole type high-temperature corrosion-resistant graded phase change heat storage heat exchanger. Comprising a shell and a multi-stage heat exchange interval arranged in the shell, the shell is provided with an HTF inlet and an HTF outlet, the multi-stage heat exchange interval is formed by splicing a plurality of heat storage units, and PCM is stored in the heat storage units; a plurality of storage grooves used for leading in PCM are formed in the heat storage unit, a plurality of flow channels used for leading in HTF are formed in the two sides of each storage groove in a penetrating mode, and the flow channels are spliced to form a channel used for guiding flowing of the HTF. The heat storage units are sequentially stacked to form the multiple heat exchange sections, the application range is wide, the stacking mode can avoid the situation that PCM is expanded and overflows after being heated, and the heat storage unit has the advantages of being high in heat exchange efficiency, simple in structure, convenient to disassemble and assemble and the like.

Description

Technical Field

[0001] The invention relates to the technical field of heat exchange 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 a thin film material and wraps the PCM inside it. The heat storage unit has a small volume and a large specific surface area. It is placed in the packed bed by stacking fillers. HTF flows through the packed bed. Due to the small volume and large number of heat storage units, HTF is easy to form a turbulent state and enhance 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 can only be used in small-scale heat storage environments. Among them, the plate type heat accumulator has the advantages of high heat transfer coefficient, compact structure and small heat loss, but is mainly limited by the poor sealing caused by the sealing material's lack of high temperature resistance and difficulty in long-term corrosion resistance, as well as the problems 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, which at least includes: a heat storage device with a gas inlet and outlet; a heat storage tube array composed of multiple heat storage tubes, which is installed in the heat storage device, and the heat storage tube is equipped with a high-temperature phase change material with a freezing point higher than 750°C, and the high-temperature phase change material is used to exchange heat with the gas entering the heat storage device. During the day, the high-temperature gas flows through the heat storage device, exchanges heat with the phase change material in the heat storage tube, and stores energy in the heat storage tube. After the heat exchange, the temperature of the gas is reduced to become a low-temperature gas, and returns to the heat collection tower / concentrating tower absorber to absorb heat; at night, the low-temperature gas flows through the heat storage device to absorb heat and then goes to the power generation system to generate electricity and do work, and the phase change material in the heat storage device is reduced in temperature after heat exchange. The heat storage and release device of the present invention increases the medium temperature of the power generation system, thereby improving the power generation efficiency of the system, and has a compact structure and economy.

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

[0005] The purpose of the present invention is to address the deficiencies in the prior art and provide a block-hole type high-temperature corrosion-resistant graded phase-change heat storage heat exchanger, which is stacked and spliced ​​into a multi-stage heat exchange interval by multiple heat storage units, and combined with the PCM stored in the heat storage unit, by graded proportioning of PCM with different phase change temperatures, it can adapt to the temperature gradient formed by the heat exchange of HTF, thereby deeply utilizing the latent heat of PCM and ensuring the heat exchange efficiency of the heat exchanger. At the same time, the heat storage unit with a spliced ​​structure is easy to disassemble and clean when it needs to be cleaned, reducing the difficulty of cleaning and solving the technical problem of inconvenient cleaning of the heat storage pipe in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solutions: A block hole type high temperature corrosion resistant graded phase change heat storage heat exchanger, comprising: a shell and a multi-stage heat exchange section arranged inside the shell, the shell is provided with an HTF inlet and an HTF outlet, the multi-stage heat exchange section is formed by splicing a plurality of heat storage units, and PCM is stored inside the heat storage unit; a plurality of storage tanks for introducing PCM are arranged inside the heat storage unit, a plurality of flow channels for introducing HTF are penetrated on both sides of the storage tank, and the plurality of flow channels are spliced ​​to form a channel for guiding the flow of HTF.

[0007] Preferably, the phase change temperature of the PCM in the multi-stage heat exchange zone gradually decreases from top to bottom.

[0008] Preferably, the outer periphery of the multi-stage heat exchange zone is coated with a thermal insulation material.

[0009] Preferably, the multi-stage heat exchange interval is fixed in the shell by a steel frame.

[0010] Preferably, a gap is left between the steel frame and the shell.

[0011] Preferably, guide plates are provided on two adjacent multi-stage heat exchange intervals.

[0012] Preferably, a plurality of edge holes which can be stacked and assembled into the flow channel are provided on both sides of the heat storage unit.

[0013] 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.

[0014] Preferably, the heat storage unit is made of graphite material, and both the inner and outer surfaces thereof are coated with a dense coating.

[0015] The beneficial effects of the present invention are: (1) The present invention divides the multi-section heat exchange area into three heat exchange zones, namely, from top to bottom: high temperature zone, medium temperature zone and low temperature zone. The heat storage units are stacked in sequence. The stacking form can avoid the expansion and overflow of the PCM after heating, and can also achieve close fit without damaging the coating, thereby greatly reducing the direct contact between the PCM and the HTF, thereby ensuring the heat exchange efficiency. At the same time, the stacked structure of the heat storage unit improves the convenience of cleaning.

[0016] (2) The present invention arranges the block hole type heat storage unit in the heat storage tank, thereby reducing the short-flow escape phenomenon of HTF, uniformly controlling the flow rate and flow direction of the HTF fluid, and adjusting the flow field of the HTF and increasing the heat exchange area by changing the stacking size and the flow channel opening, thereby reducing the resistance and improving the heat exchange efficiency.

[0017] (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 material, specifically using flexible non-metallic insulation material such as graphite fiber, aluminum silicate fiber, etc., and then coating the stacked heat storage units.

[0018] (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.

[0019] (5) The present invention provides guide plates in the multi-stage heat exchange intervals 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.

[0020] (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 under complex working conditions, such as melts with high viscosity, melts containing particles, and highly corrosive fluids. The arrangement of the PCM and HTF flow channels is combined to achieve efficient heat exchange, and a multi-stage heat exchange zone is used to achieve full energy utilization.

[0021] In summary, the present invention stacks the heat 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 disassembly and assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A cross-sectional view of the present invention taken along the storage tank; Figure 2 It is a cross-sectional view of the present invention cut along the flow channel; Figure 3 A sectional view of the present invention along the cross section of the flow channel; Figure 4for Figure 3 A magnified image of point A; Figure 5 It is a schematic structural diagram of the heat storage unit of the present invention. DETAILED DESCRIPTION The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] 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 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, rather than indicating or implying 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 only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. 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, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0024] Example like Figure 1-Figure 5 As shown, this embodiment provides a block hole type high temperature corrosion resistant hierarchical 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 undergoes phase change to absorb and release latent heat value, thereby improving heat exchange efficiency; the heat storage unit 21 is provided with a plurality of storage units for passing PCM. A storage tank 212 is provided with a plurality of flow channels 211 for introducing HTF on both sides thereof. The plurality of flow channels 211 are spliced ​​to form a channel for guiding the flow of HTF. The block-hole heat storage unit 21 is arranged in the heat storage device, which can reduce the short-flow escape phenomenon of HTF and evenly control the flow rate and flow direction of HTF fluid. The flow field of HTF can be adjusted and the heat exchange area can be increased by changing the number of stacked heat storage units 21 and the size of the opening of the flow channel 211, thereby reducing the resistance and improving the heat exchange efficiency.

[0025] 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.

[0026] At the same time, the heat storage unit 21 in the multi-stage heat exchange section 2 is installed in a longitudinal stacking manner, and 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 S-shaped direction as a whole between the shell 1 and the heat storage unit 21 to ensure the heat exchange efficiency. The HTF inlet 11 and the HTF outlet 12 can be installed with HTF fluid interfaces, as well as instrument interfaces such as temperature and pressure measurement.

[0027] In the present invention, the shell 1 has a plurality of concave portions, which divide the multi-stage heat exchange interval 2 into a plurality of heat exchange partitions. 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 unit-type block-hole heat storage unit 21 can be set with different formulas according to the temperature gradient, and the phase change temperature of PCM can be graded to ensure that the latent heat of PCM can be utilized under each temperature gradient, thereby achieving the best heat storage or heat release effect.

[0028] 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 set in the high temperature zone, and the HTF outlet 12 is set 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 deeply utilizing the latent heat of the PCM.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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 internal thermal expansion after 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.

[0033] In the present invention, the multi-stage heat exchange interval 2 is provided with a guide plate 22, which can ensure that the HTF flows smoothly and quickly flows down the channel between the shell 1 and the heat storage unit 21 without backflow and splashing, thereby ensuring heat exchange efficiency.

[0034] In the present invention, the storage tank 212 and the flow channel 211 are not interconnected, and the two do not interfere with each other, so as to ensure the normal progress of the heat exchange process.

[0035] In the present invention, a plurality of edge holes 213 which can be stacked and assembled into the flow channel 211 are arranged on both sides of the heat storage unit 21, preferably in a semicircular through-shape to facilitate stacking operation.

[0036] In the present invention, the flow channel 211 is preferably circular, which is convenient for vertical 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.

[0037] 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, and the storage tanks 212 do not pass through the bottom and are in a semi-open, incompletely closed state for storing PCM.

[0038] In the present invention, the heat accumulator as a whole can be made into a cylindrical shape.

[0039] 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 make the heat storage device 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.

[0040] In addition, the dense coating can be made of ceramic coating or silicon carbide coating, etc., and can also be made of other organic materials such as resin coating, or inorganic materials such as tantalum carbide coating, making graphite a high temperature resistant, corrosion resistant and impermeable material.

[0041] 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 protection scope 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 invention comprises: a shell and a multi-stage heat exchange section arranged inside the shell, wherein the shell is provided with an HTF inlet and an HTF outlet, the multi-stage heat exchange section is formed by splicing a plurality of heat storage units, and PCM is stored inside the heat storage unit; a plurality of storage tanks for introducing PCM are arranged inside the heat storage unit, a plurality of flow channels for introducing HTF are penetrated on both sides of the storage tank, and the plurality of flow channels are spliced ​​to form a channel for guiding the flow of HTF.

2. The block hole type high temperature corrosion resistant graded phase change heat storage heat exchanger according to claim 1 is characterized in that: The phase change temperature of the PCM in the multi-stage heat exchange interval 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 is 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 is 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: A plurality of edge holes which can be stacked and assembled into the flow channel are arranged on both sides of the heat storage unit.

8. The block hole type high temperature corrosion resistant graded phase change heat storage heat exchanger according to claim 6, characterized in that: One end of the storage tank passes through the heat storage unit, and the other end does not pass through the heat storage unit.

9. 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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