A high-temperature heat storage device, heat storage method and heat release method

Abstract

The present invention relates to a high-temperature heat storage device, a heat storage method, and a heat release method. The high-temperature heat storage device includes a high-temperature fluid flow channel, a low-temperature fluid flow channel, a reactant flow channel, and a thermochemical heat storage core. The high-temperature fluid flow channel, the low-temperature fluid flow channel, and the reactant flow channel are arranged vertically and staggered within the thermochemical heat storage core. The gaps between the flow channels within the thermochemical heat storage core are filled with a thermochemical heat storage material. The device is characterized in that the contact surface between the reactant flow channel and the thermochemical heat storage material is provided with microchannels for contact reaction between reactants and the thermochemical heat storage material and discharge of reaction products. In the present invention, the cross-sectional area of ​​the high-temperature fluid flow channel, the low-temperature fluid flow channel, and the reactant flow channel gradually increases from the center to the periphery, thereby evenly distributing the fluid in the center and periphery and increasing the heat exchange area. This results in high heat storage efficiency and meets the requirements for recovering waste heat from intermittent high-temperature heat sources.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage and heat exchanger, and relates to a high-temperature heat storage device, in particular to a thermochemical heat storage device for recovering waste heat from a high-temperature intermittent heat source. Background Art

[0002] my country has abundant waste heat resources. There are a large number of intermittent and discontinuous high-temperature heat sources in industrial production. Such heat sources cannot continuously provide heat under intermittent working conditions, and are more difficult to recover than continuous heat sources. Secondly, single-point heat sources are difficult to recycle due to their small scale. However, the cumulative calorific value of intermittent high-temperature heat sources in industrial production is much higher than that of continuous and easily recyclable heat sources. Therefore, the recovery of waste heat from intermittent high-temperature heat sources is conducive to energy conservation and emission reduction, and increases economic benefits.

[0003] Thermal energy storage can be divided into three forms: sensible heat storage, latent heat storage, and thermochemical storage. The biggest disadvantage of sensible heat storage is its low heat storage density. Latent heat storage utilizes the latent heat of materials to store thermal energy. The temperature change during latent heat storage is small, and the range of selectable phase change temperatures is wide. However, phase change materials are prone to leakage, the device is bulky, and heat transfer is slow. Thermochemical heat storage utilizes a reversible reaction to absorb and store heat, and the direction of the reversible reaction depends on temperature and pressure. Thermochemical energy storage has a higher energy storage density, good reaction reversibility, fast heat storage and release rates, and low energy loss during long-term energy storage. The reaction temperature is high, which can meet the requirements of high-temperature heat source storage.

[0004] Currently, chemical heat storage devices still have many problems, such as a non-compact structure, a small heat exchange area, low heat storage and release efficiency, and an inability to recover intermittent heat sources. To address these shortcomings, the present invention has designed a thermochemical heat storage device that evenly distributes fluids in the center and surrounding areas, increases the heat exchange area, and enhances heat storage efficiency. The staggered arrangement of high and low temperature fluid flow channels creates a compact structure, enabling the recovery and utilization of high-temperature intermittent heat sources. The present invention has a compact structure, even fluid distribution, a large heat exchange area, and high heat storage and release efficiency, and has broad application prospects. Summary of the Invention

[0005] The present invention provides a chemical heat storage device, heat storage method and heat release method for recovering high-temperature waste heat, which is used for recovering intermittent high-temperature heat sources. The device has the characteristics of compact structure, uniform fluid distribution, large heat exchange area and high heat storage and release efficiency.

[0006] The technical solutions of the present invention are as follows:

[0007] A high-temperature heat storage device comprises a high-temperature fluid flow channel, a low-temperature fluid flow channel, a reactant flow channel, and a thermochemical heat storage core. The high-temperature fluid flow channel, the low-temperature fluid flow channel, and the reactant flow channel are arranged vertically and staggered within the thermochemical heat storage core. The gaps between the flow channels within the thermochemical heat storage core are filled with a thermochemical heat storage material. The device is characterized in that microchannels for contact reaction between reactants and the thermochemical heat storage material and for discharge of reaction products are provided at the contact surface between the reactant flow channel and the thermochemical heat storage material.

[0008] The dimensions and arrangement of high-temperature fluid flow channels, low-temperature fluid flow channels, and reactant flow channels: The flow channels for the same working fluid on the cross section of the thermochemical heat storage core are centrally symmetrically distributed, and the cross-sectional area of ​​the flow channels gradually increases from the center to the periphery. Each row of flow channels has the same width, and each column of flow channels has the same length. The flow channel lengths from the inside to the outside are L1, L2, ..., L n , and satisfies C1 is a constant, 0<C1<1; the channel width and gap from inside to outside are W1, W2, ..., W n , and satisfies C2 is a constant, 0<C2<1; In addition to meeting the above conditions, it also meets L0 is the total length of the thermochemical heat storage core. This compact structure increases the fluid flow resistance from the outside to the inside, making the fluid distribution more uniform, enhancing the heat exchange effect and improving the heat exchange efficiency.

[0009] The gaps in the flow channels of the thermochemical heat storage core are filled with thermochemical heat storage materials, which are encapsulated by metal plates. The thermochemical heat storage materials are selected from one or more of calcium-based materials, metal hydrides, metal oxides, organic matter, and ammonia.

[0010] The materials of the high-temperature fluid flow channel, the low-temperature fluid flow channel and the reactant flow channel are selected to have good pressure resistance, good thermal conductivity and no reaction with the thermochemical heat storage material.

[0011] The contact surface between the reactant flow channel and the thermochemical heat storage material is provided with honeycomb holes for the reactants to contact with the thermochemical heat storage material and for the reaction products to be discharged.

[0012] A heat storage method based on a high-temperature heat storage device includes:

[0013] The high-temperature fluid flows from the high-temperature fluid inlet into the high-temperature fluid flow channel to heat the thermochemical heat storage material;

[0014] Thermochemical heat storage materials decompose into solid and gas when heated, and the gas is discharged through microchannels, completing the heat storage process.

[0015] Ca(OH)2 is selected as the thermochemical heat storage material. The high-temperature fluid flows through the high-temperature fluid flow channel, heating Ca(OH)2. Ca(OH)2 is decomposed into CaO and H2O by heat. The reaction equation is Ca(OH)2→CaO+H2O.

[0016] The heat release method based on the high-temperature heat storage device includes:

[0017] The gas flows into the reactant flow channel from the reactant inlet and reacts with the thermochemical heat storage material through the microchannel to produce an exothermic reaction;

[0018] The low-temperature fluid flows into the low-temperature fluid flow channel and absorbs the heat released by the chemical reaction of the thermochemical heat storage material;

[0019] The heated fluid flows out from the low-temperature fluid outlet, completing the heat release process.

[0020] The reactant H2O flows into the reactant flow channel from the reactant inlet, and undergoes an exothermic reaction with the thermochemical heat storage material CaO through the honeycomb pores. The reaction equation is CaO+H2O→Ca(OH)2.

[0021] Through the above technical solution, compared with the existing technology, the present invention has the following beneficial effects:

[0022] The high and low temperature fluid flow channels are staggered with the thermochemical heat storage materials, resulting in a compact structure. The use of flow channels with a gradually increasing cross-sectional area from the inside to the outside can evenly distribute the fluid in the middle and around the periphery, increase the heat exchange area, enhance the heat storage efficiency, and realize the efficient recovery and utilization of high-temperature intermittent heat sources. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below with reference to the accompanying drawings and examples.

[0024] Figure 1 Schematic diagram of the appearance of the high-temperature heat storage device of the present invention;

[0025] Figure 2 is a half-section schematic diagram of the high-temperature heat storage device of the present invention;

[0026] Figure 3 Schematic diagram of the flow channel arrangement of the high-temperature heat storage device of the present invention;

[0027] Figure 4 This is a schematic diagram of the flow channel dimensions of the high-temperature heat storage device of the present invention;

[0028] Figure 5 This is a schematic diagram of the heat storage process of the present invention;

[0029] Figure 6 It is a schematic diagram of the heat release process of the present invention;

[0030] In the figure: 1 is the high-temperature fluid inlet, 2 is the high-temperature fluid outlet, 3 is the low-temperature fluid inlet, 4 is the low-temperature fluid outlet, 5 is the reactant inlet, 6 is the reactant outlet, 7 is the heat storage core, 8 is the high-temperature fluid flow channel, 9 is the low-temperature fluid flow channel, 10 is the reactant flow channel, 11 is the thermochemical heat storage material, 12 is the metal plate, 13 is the honeycomb hole, and 14 is the heat storage device shell. DETAILED DESCRIPTION

[0031] The present invention will now be described in further detail with reference to the accompanying drawings, which are simplified schematic diagrams that illustrate the basic structure of the present invention in a schematic manner.

[0032] like Figure 1 , Figure 2 As shown, the high-temperature heat storage device of the present invention includes a thermochemical heat storage core 7 and a high-temperature fluid flow channel 8, a low-temperature fluid flow channel 9 and a reactant flow channel 10 located in the thermochemical heat storage core 7.

[0033] One end of the high-temperature fluid flow channel 8 is a high-temperature fluid inlet 1 , and the other end is a high-temperature fluid outlet 2 .

[0034] One end of the low-temperature fluid flow channel 9 is a low-temperature fluid inlet 3 , and the other end is a low-temperature fluid outlet 4 .

[0035] One end of the reactant flow channel 10 is a reactant inlet 5 , and the other end is a reactant outlet 6 .

[0036] like Figure 3 As shown, high-temperature fluid channels 8, low-temperature fluid channels 9, and reactant channels 10 are arranged vertically and interlaced, each disconnected from the other. The gaps between the channels are filled with thermochemical heat storage material 11. Honeycomb-like pores are formed on the interface between reactant channels 10 and the thermochemical heat storage material 11, allowing for contact between reactants and the material and for the discharge of reaction products. All channel materials are selected from a material of a specific thickness, good compressive strength, good thermal conductivity, and resistance to the thermochemical heat storage material. Specifically, aluminum is used.

[0037] like Figure 4 As shown, the dimensions and arrangement of the high-temperature fluid flow channel 8, the low-temperature fluid flow channel 9, and the reactant flow channel 10 meet the following rules: the high-temperature fluid flow channel, the low-temperature fluid flow channel, and the reactant flow channel are arranged vertically and staggered within the thermochemical heat storage core. The same working fluid flow channel on the cross section of the thermochemical heat storage core is centrally symmetrically distributed, and the flow channel cross-sectional area gradually increases from the center to the periphery. Each row of flow channels has the same width, and each column of flow channels has the same length. The flow channel lengths from the inside to the outside are L1, L2, ..., L n , and satisfies C1 is a constant, 0<C1<1; the channel width and gap from inside to outside are W1, W2, ..., W n , and satisfies C2 is a constant, 0<C2<1; In addition to meeting the above conditions, it also meets L0 is the total length of the heat storage core. This compact structure increases the fluid flow resistance from the outside to the inside, making the fluid distribution more uniform, enhancing the heat exchange effect and improving the heat exchange efficiency.

[0038] Specifically, the thermochemical heat storage material is Ca(OH)2, and its reaction temperature is 350-900°C. Figure 5 As shown, during heat storage, a high-temperature fluid flows in through high-temperature fluid inlet 1, flows through high-temperature fluid flow channel 8, heats thermochemical heat storage material 11, and then flows out through high-temperature fluid outlet 2 after heat exchange. Ca(OH)2 is thermally decomposed into CaO and H2O, according to the reaction equation: Ca(OH)2 → CaO + H2O. The reaction product, H2O, is discharged through honeycomb holes 13 into reactant flow channel 10. Dry air enters through reactant inlet 5, flows through reactant flow channel 10, and removes the H2O produced by the chemical reaction before being discharged through reactant outlet 6, completing the heat storage process.

[0039] like Figure 6 As shown, when the heat storage device releases heat, H₂O flows through reactant inlet 5, flows through reactant flow channel 10, and reacts with the thermochemical heat storage material CaO via honeycomb pores 13, generating an exothermic reaction according to the reaction equation: CaO + H₂O → Ca(OH)₂. Simultaneously, a low-temperature fluid flows into low-temperature fluid flow channel 9, absorbing the substantial heat released by the chemical reaction in the thermochemical heat storage material 11. The heated fluid then flows out of low-temperature fluid outlet 4, completing the heat release process.

Claims

1. A high-temperature heat storage device comprising a high-temperature fluid flow channel, a low-temperature fluid flow channel, a reactant flow channel, and a thermochemical heat storage core, wherein the high-temperature fluid flow channel, the low-temperature fluid flow channel, and the reactant flow channel are arranged vertically and staggered within the thermochemical heat storage core, and the flow channel gaps within the thermochemical heat storage core are filled with a thermochemical heat storage material; characterized in that: A microchannel for contact reaction between the reactant and the thermochemical heat storage material and discharge of the reaction product is provided on the contact surface between the reactant flow channel and the thermochemical heat storage material; The flow channels of the same working fluid on the cross section of the thermochemical heat storage core are centrally symmetrically distributed, and the cross-sectional area of ​​the flow channels gradually increases from the center to the periphery; the flow channels in each row are of equal width, and the flow channels in each column are of equal length; the flow channel lengths from the inside to the outside are L1, L2, ..., L n , C1 is a constant, 0<C1<1; the channel width and gap from inside to outside are W1, W2, ..., W n , C2 is a constant, 0<C2<1; L0 is the total length of the thermochemical heat storage core.

2. The high-temperature heat storage device according to claim 1, characterized in that: The microchannels are honeycomb-shaped holes.

3. The high-temperature heat storage device according to claim 1, characterized in that: The thermochemical heat storage material is selected from one or more of calcium-based materials, metal hydrides, metal oxides, organic matter, and ammonia.

4. The high-temperature heat storage device according to claim 3, characterized in that: The thermochemical heat storage material is Ca(OH)2 and the reactant is H2O.

5. The heat storage method according to any one of claims 1 to 4, characterized in that: include: The high-temperature fluid flows from the high-temperature fluid inlet into the high-temperature fluid flow channel to heat the thermochemical heat storage material; Thermochemical heat storage materials decompose into solid and gas when heated, and the gas is discharged through microchannels, completing the heat storage process.

6. The heat storage method of the high-temperature heat storage device according to claim 5, characterized in that: Ca(OH)2 is selected as the thermochemical heat storage material. The high-temperature fluid flows through the high-temperature fluid flow channel, heating Ca(OH)2. Ca(OH)2 is decomposed into CaO and H2O by heat. The reaction equation is Ca(OH)2→CaO+H2O.

7. The heat release method of the high-temperature heat storage device according to any one of claims 1 to 4, characterized in that: include: The gas flows into the reactant flow channel from the reactant inlet and reacts with the thermochemical heat storage material through the microchannel to produce an exothermic reaction; The low-temperature fluid flows into the low-temperature fluid flow channel and absorbs the heat released by the chemical reaction of the thermochemical heat storage material; The heated fluid flows out from the low-temperature fluid outlet, completing the heat release process.

8. The heat release method of the high-temperature heat storage device according to claim 7, characterized in that: The reactant H2O flows into the reactant flow channel from the reactant inlet, and undergoes an exothermic reaction with the thermochemical heat storage material CaO through the honeycomb pores. The reaction equation is CaO+H2O→Ca(OH)2.

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