Stacking method of multi-stage particle packed bed layer and heat exchange and storage equipment of multi-stage particle packed bed layer

Abstract

The invention provides an accumulation method of a multi-stage particle packed bed layer and heat exchange and storage equipment thereof, and belongs to the technical field of phase change heat storage and heat exchange.The heat exchange and storage equipment comprises a vertically-arranged heat storage tank, a fluid inlet channel is formed in the upper end of the heat storage tank, and a fluid outlet channel is formed in the lower end of the heat storage tank; the heat storage tank is internally and sequentially provided with a plurality of heat storage bed layers from top to bottom, each heat storage bed layer is internally and orderly filled with PCM particles, the stacking method of the multi-stage particle filling bed layers and the heat exchange and heat storage equipment of the multi-stage particle filling bed layers are provided, the heat storage bed layers are divided into five layers in the heat storage tank, and the heat exchange and heat storage equipment of the multi-stage particle filling bed layers is arranged in the heat storage tank. The PCMs with different phase change temperatures and different phase change enthalpy values are arranged according to a certain sequence to form the composite PCM with a certain phase change temperature gradient, and the stepped arrangement has the advantage that the heat transfer temperature difference between the PCMs and heat transfer fluid can be basically kept constant, so that the heat exchange efficiency of the system can be integrally improved.

Description

Technical Field

[0001] The invention belongs to the technical field of phase change heat storage and heat exchange, and specifically relates to a stacking method of a multi-stage particle filling bed and a heat exchange and heat storage device thereof. Background Art

[0002] Chemical heat storage is to store the heat of chemical reactions in chemical substances, store energy through endothermic reactions, and release energy through reverse reactions. The heat storage density of chemical heat storage is about 10 times that of sensible heat storage. Chemical heat storage has the advantage of high heat storage density. However, chemical heat storage has disadvantages such as complex reaction process, high equipment performance requirements, and low cost performance. In actual application, it is prone to problems such as poor equipment tightness and material corrosion. At present, this technology is still in the early research stage. Sensible heat storage is to store and release heat by changing the temperature of the substance itself, relying on the thermophysical properties of the heat storage material. Sensible heat storage applications usually only require temperature control, simple operation and management, and are currently the most widely used heat storage method. However, this type of material has a low heat storage density, large temperature changes, and the system occupies a large space. It is difficult to use in a compact space and has certain application limitations.

[0003] Phase change heat storage absorbs or releases latent heat through the material during the phase change process. Phase change heat storage materials can be divided into organic, molten salt, alloy and composite types. Phase change materials mainly change in the three phases of solid, liquid and gas. Among them, solid-liquid phase change materials have a large energy storage density and small volume and temperature changes during the phase change process. They are the main research objects at present. Phase change materials have good application prospects in the fields of solar thermal utilization, waste heat recovery, building energy conservation, etc. Phase change heat storage usually refers to solid-liquid phase change. The heat storage density of phase change heat storage is 5 to 10 times that of sensible heat storage, which can greatly reduce the size of equipment and the footprint of the system; the temperature and volume changes of phase change materials are small during the phase change process, the operation and control are simple, and the safety of heat storage control is improved; at the same time, the cost of phase change heat storage is lower than that of sensible heat storage, chemical heat storage and most electricity storage technologies. Therefore, phase change heat storage is a heat storage technology with relatively balanced performance in all aspects and broad application prospects.

[0004] The particle bed packed bed is to place the reaction materials in a fixed bed layer, and react through the particle materials in the bed layer. In the application of particle packed beds, disordered packed beds are the most common type. This stacking method has the advantage of low cost due to the randomness of its generation process. However, studies have pointed out that the distribution of particles inside the disordered packed bed is disordered, which causes the flow path of the fluid therein to become complex and changeable. This complexity not only increases the resistance to flow, but also causes a large pressure drop loss. In addition, the unevenness of the stacking structure will also affect the heat transfer effect of the fluid, causing uneven heat transfer, which makes the traditional particle bed packed bed structure have some problems, such as low reaction efficiency and uneven mass transfer. Therefore, a stacking method of a multi-stage particle packed bed and its heat exchange and heat storage equipment are needed to solve this problem. Summary of the invention

[0005] To achieve the above-mentioned object, the present invention provides a heat exchange and heat storage device with a multi-stage particle-filled bed, comprising a vertically arranged heat storage tank, a fluid inlet channel is opened at the upper end of the heat storage tank, a fluid outlet channel is opened at the lower end of the heat storage tank, and a plurality of heat storage beds are arranged in sequence from top to bottom in the heat storage tank, and each of the heat storage beds is filled with PCM particles in an orderly manner.

[0006] Furthermore, the heat storage tank is composed of an upper tank body, a middle tank body and a lower tank body from top to bottom, the middle tank body is cylindrical, and a plurality of heat storage beds are arranged in the middle tank body;

[0007] The upper tank body and the lower tank body are both conical, the cone head of the upper tank body faces upward, the fluid inlet channel is located at the upper end of the upper tank body, the cone head of the lower tank body faces downward, and the fluid outlet channel is located at the lower end of the lower tank body.

[0008] Furthermore, an upper connecting flange is horizontally provided between the upper tank body and the middle tank body, and the lower end of the upper tank body and the upper end of the middle tank body are fixedly connected through the upper connecting flange;

[0009] A lower connecting flange is horizontally arranged between the lower tank body and the middle tank body, and the upper end of the lower tank body and the lower end of the middle tank body are fixedly connected through the lower connecting flange.

[0010] Furthermore, an upper positioning bracket is horizontally provided on the upper side of each heat storage bed layer, a lower positioning bracket is horizontally provided on the bottom of each heat storage bed layer, and metal brackets are horizontally provided between two adjacent heat storage beds, and the metal brackets, the upper positioning brackets, and the lower positioning brackets are all fixedly connected to the middle tank body.

[0011] Furthermore, a top flow equalizer is provided above the middle tank body, and the top flow equalizer is located between the upper connecting flange and the upper positioning bracket, and a bottom flow equalizer is provided below the middle tank body.

[0012] Furthermore, the heat storage bed layer is preferably arranged as five layers.

[0013] Furthermore, the diameter of the PCM particles filled in each layer decreases layer by layer from top to bottom.

[0014] A method for stacking a multi-stage particle packed bed comprises the following steps:

[0015] S1: First, the heat storage tank is built and installed, and then the upper positioning bracket, the lower positioning bracket, and the metal bracket are pre-assembled in the middle tank body of the heat storage tank to form a multi-level heat storage bed layer as a whole, wherein each layer of the heat storage bed can be supported by a support grid;

[0016] S2: The multi-level heat storage bed in the heat storage tank is set to five layers, and then the five layers of heat storage bed are filled with PCM particles from bottom to top, layer by layer in an orderly manner. When the support grid and the bed are filled, by adjusting the upper positioning bracket and the lower positioning bracket, as well as the characteristic size of the metal bracket, a stacking bed with different stacking methods or the same stacking method but different particle spacing can be formed.

[0017] A method for preparing PCM particles in a multi-stage particle packing bed comprises the following steps:

[0018] M1: heating an inorganic hydrated salt phase change material to a temperature 30°C to 50°C higher than its own phase change temperature, and heating an organic phase change material to a temperature 30°C to 50°C higher than its own phase change temperature, and then obtaining an inorganic hydrated salt phase change material that changes into a liquid state and an organic phase change material that changes into a liquid state respectively; wherein the phase change temperature of the inorganic hydrated salt phase change material is 35°C to 55°C, and the phase change temperature of the organic phase change material is 35°C to 65°C, and the phase change temperature of the inorganic hydrated salt phase change material is lower than the phase change temperature of the organic phase change material;

[0019] M2: heating the ceramsite to a temperature 35-55°C higher than the phase change temperature of the inorganic hydrated salt phase change material, and then placing it in a reactor and evacuating it to a relative vacuum degree of -20kPa--100kPa, and then adding the excess inorganic hydrated salt phase change material obtained in step M1 into the reactor under negative pressure, so that the ceramsite is completely immersed in the inorganic hydrated salt phase change material, and then eliminating the vacuum state to normal pressure, and finally filtering to obtain the ceramsite adsorbed with the inorganic hydrated salt phase change material;

[0020] M3: The ceramsite adsorbed with inorganic hydrated salt phase change material prepared in step M2 is heated to a temperature 35°C to 65°C higher than the phase change temperature of the organic phase change material. Then, under the action of negative pressure, the organic phase change material that has changed into a liquid state is passed through a porous nozzle or an atomizer to ensure that the phase change material evenly covers each ceramsite. The ceramsite is then added to the reaction device to completely immerse the ceramsite in the organic phase change material that has changed into a liquid state. The vacuum state is eliminated to normal pressure, and finally filtered to obtain the phase change ceramsite.

[0021] The advantages of the present invention are as follows: the main invention provides a stacking method of a multi-level particle packed bed and a heat exchange and heat storage device thereof, designs a new, orderly stacked, packed bed type, stepped phase change heat storage, multi-level particle packed bed heat exchange and heat storage device, improves the heat storage efficiency and heat storage density of the traditional packed bed structure, divides the heat storage bed into five layers in the heat storage tank, arranges and places PCMs with different phase change temperatures and different phase change enthalpy values ​​in a certain order, and forms a composite PCM with a certain phase change temperature gradient. The advantage of the stepped arrangement is that the heat transfer temperature difference between the PCM and the heat transfer fluid can be basically kept constant, which can improve the heat exchange efficiency of the system as a whole. The heat storage structure of the heat storage bed comprehensively considers the two important evaluation indicators of the heat storage device, heat storage rate and heat storage density, and takes the maximum heat storage rate density of the heat storage bed as the design principle. The optimal combination of the diameter of the heat storage particles in the heat storage bed is obtained through optimization design, so that the heat storage device has the best heat storage performance. The invention proposes an ordered stacking structure with multiple gradients. Under the condition of maintaining the same level of heat transfer characteristics, the heat transfer performance may be further improved by rationally designing the stacking structure.

[0022] The present invention is described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of the present invention.

[0024] Explanation of the reference numerals: 1. heat storage tank; 101. upper tank body; 102. middle tank body; 103. lower tank body; 2. fluid inlet channel; 3. fluid outlet channel; 4. heat storage bed layer; 5. PCM particles; 6. upper connecting flange; 7. lower connecting flange; 8. upper positioning bracket; 9. lower positioning bracket; 10. metal bracket; 11. top flow equalizer; 12. bottom flow equalizer. DETAILED DESCRIPTION

[0025] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose, the specific implementation methods, structural features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and embodiments.

[0026] 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.

[0027] In the description of the present invention, it is necessary to understand that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "aligned", "overlap", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations 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 referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0028] The terms "first" and "second" are used for descriptive purposes only and should not 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, unless otherwise specified, "plurality" means two or more.

[0029] Example 1

[0030] This embodiment provides Figure 1 A heat exchange and heat storage device with a multi-stage particle-filled bed shown in the figure comprises a vertically arranged heat storage tank 1, a fluid inlet channel 2 is provided at the upper end of the heat storage tank 1, and the fluid inlet channel 2 is the inlet channel of the fluid in the heat storage process, and a fluid outlet channel 3 is provided at the lower end of the heat storage tank 1, and the fluid outlet channel 3 is the outlet channel of the fluid in the heat storage process. A plurality of heat storage beds 4 are arranged in sequence from top to bottom in the heat storage tank 1, and each heat storage bed layer 4 is orderly filled with PCM particles 5, which are phase change heat storage material particles, which are accumulated in the heat storage tank 1 to form a packed bed, and the gaps thereof are used as heat transfer channels, wherein the heat storage devices such as the heat storage tank 1 and the heat storage particles are made of stainless steel metal, and the heat storage particles are filled with low-temperature organic phase change materials, inorganic salts or high-temperature molten salt phase change materials.

[0031] Furthermore, the heat storage tank 1 is composed of an upper tank body 101, a middle tank body 102 and a lower tank body 103 from top to bottom, the middle tank body 102 is cylindrical, and a plurality of heat storage beds 4 are arranged at the middle tank body 102;

[0032] The upper tank body 101 and the lower tank body 103 are both conical in shape, with the cone head of the upper tank body 101 facing upward, the fluid inlet channel 2 located at the upper end of the upper tank body 101 , the cone head of the lower tank body 103 facing downward, and the fluid outlet channel 3 located at the lower end of the lower tank body 103 .

[0033] Furthermore, an upper connecting flange 6 is horizontally provided between the upper tank body 101 and the middle tank body 102, and the lower end of the upper tank body 101 and the upper end of the middle tank body 102 are fixedly connected through the upper connecting flange 6;

[0034] A lower connecting flange 7 is horizontally provided between the lower tank body 103 and the middle tank body 102 , and the upper end of the lower tank body 103 and the lower end of the middle tank body 102 are fixedly connected via the lower connecting flange 7 .

[0035] Furthermore, an upper positioning bracket 8 is horizontally provided on the upper side of each heat storage bed layer 4, a lower positioning bracket 9 is horizontally provided at the bottom of each heat storage bed layer 4, and a metal bracket 10 is horizontally provided between two adjacent heat storage beds 4, and the metal bracket 10, the upper positioning bracket 8, and the lower positioning bracket 9 are all fixedly connected to the middle tank body 102.

[0036] Furthermore, a top flow equalizer 11 is provided above the middle tank body 102 , and the top flow equalizer 11 is located between the upper connecting flange 6 and the upper positioning bracket 8 , and a bottom flow equalizer 12 is provided below the middle tank body 102 .

[0037] Furthermore, the heat storage bed layer 4 is preferably arranged as five layers.

[0038] Furthermore, the diameter of the PCM particles 5 filled in each layer decreases layer by layer from top to bottom.

[0039] A method for stacking a multi-stage particle packed bed comprises the following steps:

[0040] S1: First, the heat storage tank 1 is built and installed, and then the upper positioning bracket 8, the lower positioning bracket 9, and the metal bracket 10 are pre-assembled in the middle tank body 102 of the heat storage tank 1 to form a multi-level heat storage bed layer 4 as a whole, wherein each layer of the heat storage bed layer 4 can be supported by a support grid;

[0041] S2: The multi-level heat storage bed layer 4 in the heat storage tank 1 is set to five layers, and then the five layers of heat storage bed layers 4 are filled with PCM particles 5 of different diameters from bottom to top, one layer at a time, in an orderly manner. The diameter of the PCM particles 5 filled in each layer of the heat storage bed layer 4 increases step by step from bottom to top, and the overall five layers of the heat storage bed layer 4 are arranged in a stepped phase change manner. When the support grid and the bed layer are filled, by adjusting the characteristic dimensions of the upper positioning bracket 8 and the lower positioning bracket 9, as well as the metal bracket 10, a stacking bed with different stacking methods or the same stacking method but different particle spacing can be formed.

[0042] Furthermore, the stepped phase change technology is to arrange PCM particles 5 with different phase change temperatures and different phase change enthalpy values ​​in a certain order to form a composite PCM bed with a certain temperature gradient. Compared with the single-stage phase change heat storage system, the advantage of the stepped arrangement is that the heat transfer temperature difference between the PCM and the heat transfer fluid can be basically kept constant, which can improve the heat exchange efficiency of the system as a whole. Among them, the stepped phase change temperatures of the five-layer heat storage bed 4 are 375°C, 360°C, 340°C, 320°C, and 305°C respectively. The heat storage and release time of the stepped phase change heat storage system is relatively short, and the five-stage phase change system can still return to its original state after multiple high and low temperature cycles, and has good reusability.

[0043] A method for preparing PCM particles in a multi-stage particle packing bed comprises the following steps:

[0044] M1: heating an inorganic hydrated salt phase change material to a temperature 30°C to 50°C higher than its own phase change temperature, and heating an organic phase change material to a temperature 30°C to 50°C higher than its own phase change temperature, and then obtaining an inorganic hydrated salt phase change material that changes into a liquid state and an organic phase change material that changes into a liquid state respectively; wherein the phase change temperature of the inorganic hydrated salt phase change material is 35°C to 55°C, and the phase change temperature of the organic phase change material is 35°C to 65°C, and the phase change temperature of the inorganic hydrated salt phase change material is lower than the phase change temperature of the organic phase change material;

[0045] M2: heating the ceramsite to a temperature 35-55°C higher than the phase change temperature of the inorganic hydrated salt phase change material, and then placing it in a reactor and evacuating it to a relative vacuum degree of -20kPa--100kPa, and then adding the excess inorganic hydrated salt phase change material obtained in step M1 into the reactor under negative pressure, so that the ceramsite is completely immersed in the inorganic hydrated salt phase change material, and then eliminating the vacuum state to normal pressure, and finally filtering to obtain the ceramsite adsorbed with the inorganic hydrated salt phase change material;

[0046] M3: The ceramsite adsorbed with inorganic hydrated salt phase change material prepared in step M2 is heated to a temperature 35°C to 65°C higher than the phase change temperature of the organic phase change material. Then, under the action of negative pressure, the organic phase change material that has changed into a liquid state is passed through a porous nozzle or an atomizer to ensure that the phase change material evenly covers each ceramsite. The ceramsite is then added to the reaction device to completely immerse the ceramsite in the organic phase change material that has changed into a liquid state. The vacuum state is eliminated to normal pressure, and finally filtered to obtain the phase change ceramsite.

[0047] The main invention provides a stacking method of a multi-level particle packed bed and a heat exchange and heat storage device thereof, and designs a new, orderly stacked, packed bed type, stepped phase change heat storage, multi-level particle packed bed heat exchange and heat storage device, which improves the heat storage efficiency and heat storage density of the traditional packed bed structure. By dividing the heat storage bed 4 into five layers in the heat storage tank 1, the PCMs with different phase change temperatures and different phase change enthalpy values ​​are arranged and placed in a certain order to form a composite PCM with a certain phase change temperature gradient. The advantage of the stepped arrangement is that the heat transfer temperature difference between the PCM and the heat transfer fluid can be basically kept constant, which can improve the heat exchange efficiency of the system as a whole. The heat storage structure of the heat storage bed 4 comprehensively considers the two important evaluation indicators of the heat storage device, heat storage rate and heat storage density, and takes the maximum heat storage rate density of the heat storage bed 4 as the design principle. The optimal combination of the diameter of the heat storage particles in the heat storage bed 4 is obtained through optimization design, so that the heat storage device has the best heat storage performance. The invention proposes an ordered stacking structure with multiple gradients. Under the condition of maintaining the same level of heat transfer characteristics, the heat transfer performance may be further improved by rationally designing the stacking structure.

[0048] When in use, the heat storage tank 1 is first established and installed, and then the upper positioning bracket 8 and the lower positioning bracket 9, as well as the metal bracket 10 are pre-assembled in the middle tank body 102 of the heat storage tank 1 to form a multi-stage heat storage bed 4 as a whole, wherein each layer of the heat storage bed 4 can be supported by a supporting grid, and then the multi-stage heat storage bed 4 in the heat storage tank 1 is set to five layers, and then the five layers of the heat storage bed 4 are filled from bottom to top, one layer at a time, in an orderly manner, wherein the diameter of the PCM particles 5 filled in each layer of the heat storage bed 4 increases step by step from bottom to top, and the overall five layers of the heat storage bed 4 are arranged in steps. When the support grid and the bed interval are filled, by adjusting the characteristic dimensions of the upper positioning bracket 8 and the lower positioning bracket 9, as well as the metal bracket 10, a stacking bed with different stacking methods or the same stacking method but different particle spacing can be formed;

[0049] After the establishment is completed, first, the hot fluid with a higher temperature connected to the heat storage tank 1 enters the system through the inlet channel of the upper tank body 101. This step is used to ensure that the hot fluid can be evenly distributed throughout the heat storage device;

[0050] Secondly, after the hot fluid enters the upper tank body 101, it enters the middle tank body 102 through the top flow equalizer 11, wherein the main function of the top flow equalizer 11 is to ensure that the hot fluid can be evenly distributed before entering the heat storage bed layer 4 area, avoiding local overheating or uneven heating, thereby improving the heat storage efficiency. After entering the middle tank body 102 through the top flow equalizer 11, the hot fluid enters the heat storage bed layer 4 area, and then the hot fluid flows through the five-stage heat storage bed layer 4 area in sequence, and through the PCM particles 5 according to the designed step arrangement, the hot fluid can fully contact and exchange heat with the PCM particles 5, thereby achieving more efficient heat energy exchange;

[0051] In addition, in the heat storage bed 4 area, the thermal fluid contacts the PCM particles 5, and transfers heat energy to the PCM particles 5 by heat conduction and convection. After absorbing the heat energy, these particles will absorb a large amount of latent heat in this process. At the same time, the temperature of the particles themselves rises, and the heat energy is also stored in the form of sensible heat. Due to the change in the diameter of the PCM particles 5 in the heat storage bed 4, a step-by-step phase change process can be achieved, thereby achieving a wider temperature range and a higher thermal energy utilization rate in the entire heat storage process;

[0052] The preparation method of PCM particles is as follows:

[0053] First, an inorganic hydrated salt phase change material is heated to a temperature 30°C to 50°C higher than its own phase change temperature, and at the same time, an organic phase change material is heated to a temperature 30°C to 50°C higher than its own phase change temperature, and then an inorganic hydrated salt phase change material that changes into a liquid state and an organic phase change material that changes into a liquid state are obtained respectively; wherein the phase change temperature of the inorganic hydrated salt phase change material is 35°C to 55°C, and the phase change temperature of the organic phase change material is 35°C to 65°C, and the phase change temperature of the inorganic hydrated salt phase change material is lower than the phase change temperature of the organic phase change material;

[0054] The ceramsite is then heated to a temperature 35 to 55° C. higher than the phase change temperature of the inorganic hydrated salt phase change material, and then placed in a reactor and evacuated to a relative vacuum degree of -20 kPa to -100 kPa, and then the excess inorganic hydrated salt phase change material obtained in step M1 that has changed into a liquid state is added to the reactor under negative pressure, so that the ceramsite is completely immersed in the inorganic hydrated salt phase change material that has changed into a liquid state, and then the vacuum state is eliminated to normal pressure, and finally filtered to obtain ceramsite adsorbed with the inorganic hydrated salt phase change material;

[0055] Then, the ceramsite adsorbed with inorganic hydrated salt phase change material prepared in step M2 is heated to a temperature 35°C to 65°C higher than the phase change temperature of the organic phase change material. Then, under the action of negative pressure, the organic phase change material that has changed into a liquid state is passed through a porous nozzle or an atomizer to ensure that the phase change material evenly covers each ceramsite. The ceramsite is then added to the reaction device to completely immerse the ceramsite in the organic phase change material that has changed into a liquid state. The vacuum state is eliminated to normal pressure, and finally filtered to obtain the phase change ceramsite.

[0056] The preferred inorganic hydrated salt phase change materials are disodium hydrogen phosphate dodecahydrate (Na2HPO4·12H2O), whose phase change temperature is about 35°C, sodium sulfate (Na2SO4·10H2O), whose phase change temperature is about 32°C, and sodium acetate (CH3COONa·3H2O), whose phase change temperature is about 58°C.

[0057] The preferred organic phase change material is phase change paraffin, and its phase change temperature is 10 to 50°C;

[0058] The preferred inorganic water and salt materials and organic phase change materials can be selected from materials with other phase change temperature gradients according to the temperature setting of the stepped phase change thermal storage system.

[0059] Finally, after the hot fluid flows through the bottom heat storage bed 4, it enters the lower tank 103 through the bottom fluid distribution, and then as the hot fluid flows in the heat storage bed 4, its temperature gradually decreases, and finally turns into a cooled low-temperature working fluid, which is discharged through the fluid outlet channel 3 at the bottom of the lower tank 103, and the entire heat storage process is completed. During the entire heat storage process, the heat storage efficiency can be maximized and heat loss can be reduced by precisely controlling the flow rate of the hot fluid, the particle distribution of the heat storage bed 4, and the selection of phase change materials. The design of the heat storage device takes into account the adaptability under different environmental conditions, and can work stably under a variety of temperature and pressure conditions, ensuring the reliability and durability of the heat storage process.

[0060] Among them, it can be analyzed from the heat storage process that for the heat storage device of the heat storage bed layer 4, along the direction of fluid flow, the temperature gradually decreases due to the continuous heat exchange between the heat exchange fluid and the phase change material. As for the entire heat storage device, in the fluid inlet channel 2, the heat exchange fluid temperature is high, the heat exchange temperature difference is large, and the heat exchange effect is good; while in the fluid outlet channel 3, the heat exchange fluid temperature is low, the heat exchange temperature difference is reduced, and the heat exchange effect becomes worse. For this reason, arranging heat storage particles with larger diameters on the upper layer of the heat storage device can make the heat storage device have a higher heat storage density, and arranging heat storage particles with smaller diameters on the lower layer of the heat storage device can increase the heat exchange area and improve the heat storage rate of the heat storage device. In addition, from the perspective of the overall structure of the heat storage device, compared with a single-layer heat storage particle device with the same diameter, a five-layer heat storage device with variable particle diameters can increase the heat storage rate density of the heat storage device, so that the heat storage performance is optimal.

[0061] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A heat exchange and heat storage device with a multi-stage particle packed bed, characterized in that: The invention comprises a heat storage tank (1) arranged vertically, wherein a fluid inlet channel (2) is provided at the upper end of the heat storage tank (1), and a fluid outlet channel (3) is provided at the lower end of the heat storage tank (1), and a plurality of heat storage beds (4) are arranged in sequence from top to bottom in the heat storage tank (1), and each of the heat storage beds (4) is filled with PCM particles (5) in an orderly manner.

2. The heat exchange and heat storage device of the multi-stage particle packed bed as claimed in claim 1, characterized in that: The heat storage tank (1) is composed of an upper tank body (101), a middle tank body (102) and a lower tank body (103) from top to bottom, the middle tank body (102) is cylindrical, and a plurality of heat storage beds (4) are arranged in the middle tank body (102); The upper tank body (101) and the lower tank body (103) are both conical in shape, the cone head of the upper tank body (101) faces upward, the fluid inlet channel (2) is located at the upper end of the upper tank body (101), the cone head of the lower tank body (103) faces downward, and the fluid outlet channel (3) is located at the lower end of the lower tank body (103).

3. The heat exchange and heat storage device of the multi-stage particle packed bed as claimed in claim 2, characterized in that: An upper connecting flange (6) is horizontally provided between the upper tank body (101) and the middle tank body (102), and the lower end of the upper tank body (101) and the upper end of the middle tank body (102) are fixedly connected via the upper connecting flange (6); A lower connecting flange (7) is horizontally arranged between the lower tank body (103) and the middle tank body (102), and the upper end of the lower tank body (103) and the lower end of the middle tank body (102) are fixedly connected via the lower connecting flange (7).

4. The heat exchange and heat storage device of the multi-stage particle packed bed as claimed in claim 3, characterized in that: An upper positioning bracket (8) is horizontally arranged on the upper side of each heat storage bed layer (4), a lower positioning bracket (9) is horizontally arranged on the bottom of each heat storage bed layer (4), and a metal bracket (10) is horizontally arranged between two adjacent heat storage beds (4), and the metal bracket (10), the upper positioning bracket (8), and the lower positioning bracket (9) are all fixedly connected to the middle tank body (102).

5. The heat exchange and heat storage device of the multi-stage particle packed bed as claimed in claim 4, characterized in that: A top flow equalizer (11) is provided above the middle tank body (102), and the top flow equalizer (11) is located between the upper connecting flange (6) and the upper positioning bracket (8). A bottom flow equalizer (12) is provided below the middle tank body (102).

6. The heat exchange and heat storage device of the multi-stage particle packed bed as claimed in claim 2, characterized in that: The heat storage bed layer (4) is preferably arranged to have five layers.

7. The heat exchange and heat storage device of the multi-stage particle packed bed as claimed in claim 6, characterized in that: The diameter of the PCM particles (5) filled in each layer decreases layer by layer from top to bottom.

8. The heat exchange and heat storage device of the multi-stage particle packed bed as claimed in claim 7, characterized in that: The PCM particles (5) are inorganic heat storage ceramsite, and the heat storage ceramsite is filled with inorganic hydrated salt phase change material and organic phase change material.

9. A method for stacking a multi-stage particle packed bed, characterized in that: The steps include: S1: firstly, the heat storage tank (1) is built and installed, and then the upper positioning bracket (8), the lower positioning bracket (9), and the metal bracket (10) are pre-assembled in the middle tank body (102) of the heat storage tank (1) to form a multi-level heat storage bed layer (4) as a whole, wherein each layer of the heat storage bed layer (4) can be supported by a supporting grid; S2: The multi-level heat storage bed (4) in the heat storage tank (1) is set to five layers, and then the five layers of heat storage bed (4) are filled with PCM particles (5) from bottom to top, layer by layer, in an orderly manner. When the support grid and the bed are filled, by adjusting the characteristic dimensions of the upper positioning bracket (8) and the lower positioning bracket (9), as well as the metal bracket (10), a stacking bed with different stacking methods or the same stacking method but different particle spacing can be formed.

10. A method for preparing PCM particles in a multi-stage particle packing bed, characterized in that: The steps include: M1: heating an inorganic hydrated salt phase change material to a temperature 30°C to 50°C higher than its own phase change temperature, and heating an organic phase change material to a temperature 30°C to 50°C higher than its own phase change temperature, and then obtaining an inorganic hydrated salt phase change material that changes into a liquid state and an organic phase change material that changes into a liquid state respectively; wherein the phase change temperature of the inorganic hydrated salt phase change material is 35°C to 55°C, and the phase change temperature of the organic phase change material is 35°C to 65°C, and the phase change temperature of the inorganic hydrated salt phase change material is lower than the phase change temperature of the organic phase change material; M2: heating the ceramsite to a temperature 35-55°C higher than the phase change temperature of the inorganic hydrated salt phase change material, and then placing it in a reactor and evacuating it to a relative vacuum degree of -20kPa--100kPa, and then adding the excess inorganic hydrated salt phase change material obtained in step M1 into the reactor under negative pressure, so that the ceramsite is completely immersed in the inorganic hydrated salt phase change material, and then eliminating the vacuum state to normal pressure, and finally filtering to obtain the ceramsite adsorbed with the inorganic hydrated salt phase change material; M3: The ceramsite adsorbed with inorganic hydrated salt phase change material prepared in step M2 is heated to a temperature 35°C to 65°C higher than the phase change temperature of the organic phase change material. Then, under the action of negative pressure, the organic phase change material that has changed into a liquid state is passed through a porous nozzle or an atomizer to ensure that the phase change material evenly covers each ceramsite. The ceramsite is then added to the reaction device to completely immerse the ceramsite in the organic phase change material that has changed into a liquid state. The vacuum state is eliminated to normal pressure, and finally filtered to obtain the phase change ceramsite.

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