A thermochemical energy storage and release system and a method for charging the heat storage and release material.

Abstract

This invention discloses a thermochemical energy storage and release system and a method for charging the heat storage and release material, overcoming the shortcomings of slow charging response and low efficiency in existing thermochemical energy storage systems. The thermochemical energy storage and release system of this invention includes a reactor and a microwave generator and heat storage and release material disposed within the reactor. This invention charges the heat storage and release material by directly applying microwaves, significantly improving the charging response speed, reasonably reducing the charging temperature, and accelerating the regeneration process of thermochemical energy storage, thereby improving the overall efficiency and flexibility of the system.

Description

Technical Field

[0001] This invention belongs to the field of thermochemical energy storage and release technology, specifically relating to a thermochemical energy storage and release system and a method for charging heat storage and release materials. Background Technology

[0002] Renewable energy and waste heat recovery are key components of achieving carbon neutrality. However, addressing the discontinuity of renewable energy and waste heat, as well as the volatility of end-user energy demand, presents significant challenges. From the demand side, many industrial processes require intermittent heating or steam production, with demand peaks occurring infrequently, but necessitating substantial investment in heat-generating equipment (such as backup electric boilers) to prepare for them, while also significantly increasing the capacity requirements of power supply equipment.

[0003] To effectively address these issues, using energy storage technology as an intermediary is one effective solution. This approach can not only balance the discontinuities between energy production and energy demand but also improve the flexibility and resilience of the energy supply chain.

[0004] Thermochemical energy storage is a commonly used energy storage technology, but the traditional charging method involves heating the heat storage and release materials through electric heating, which results in slow charging response and low efficiency. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defects of slow charging response speed and low efficiency of thermochemical energy storage systems in the prior art, thereby providing a thermochemical energy storage and release system and a charging method for heat storage and release materials.

[0006] To this end, the present invention provides the following technical solution.

[0007] In a first aspect, the present invention provides a thermochemical energy storage and release system, comprising a reactor and a microwave generator and a heat storage and release material disposed in the reactor.

[0008] Furthermore, the reactor includes a tank with openings at the top and bottom, and both the top and bottom openings of the tank are provided with porous wire mesh.

[0009] The microwave generator and the heat storage material are both housed inside the tank.

[0010] Furthermore, the mesh size of the porous wire mesh should not exceed twice the size of the heat storage material;

[0011] Preferably, the size of the heat storage and release material is >5μm, and the mesh size is 5-10μm.

[0012] Furthermore, it also includes a first thermocouple disposed in the tank, wherein one or more of the first thermocouples are disposed;

[0013] Preferably, the first thermocouple is a fiber optic thermocouple.

[0014] Furthermore, the heat storage and release material is arranged in layers inside the tank, and the size of the heat storage and release material gradually decreases from bottom to top;

[0015] Preferably, a porous baffle is provided between two adjacent layers of heat storage and release material;

[0016] Preferably, the heat storage and release material is arranged in three layers inside the tank: a lower layer, a middle layer, and an upper layer. The size of the heat storage and release material in the lower layer is 1.5 to 3 mm, the size of the heat storage and release material in the middle layer is 0.5 to 1.5 mm, and the size of the heat storage and release material in the upper layer is 0.1 to 0.5 mm.

[0017] Preferably, the height ratio of the lower layer, the middle layer and the upper layer is (1~2):(1~2):(1~2); for example, it can be 1:1:1, 1:2:1, 2:1:1 or 1:1:2.

[0018] Furthermore, the heat storage and release material satisfies at least one of the following conditions:

[0019] (1) The lower heat storage and release material includes a first thermochemical heat storage material and a first carrier;

[0020] Preferably, the mass ratio of the first thermochemical heat storage material to the first carrier is (50-65):(50-35);

[0021] Preferably, the first thermochemical heat storage material includes at least one of CaO / Ca(OH)2, MgO / Mg(OH)2, and BaO / Ba(OH)2;

[0022] Preferably, the first carrier includes at least one of vermiculite, zeolite, or silicon carbide;

[0023] (2) The middle layer heat storage and release material includes a second thermochemical heat storage material and a second carrier;

[0024] Preferably, the mass ratio of the second thermochemical heat storage material to the second carrier is (65-75):(35-25);

[0025] Preferably, the second thermochemical heat storage material includes at least one of CaO / Ca(OH)2, MgO / Mg(OH)2, and BaO / Ba(OH)2;

[0026] Preferably, the second carrier includes at least one of vermiculite, zeolite, or silicon carbide;

[0027] (3) The upper heat storage and release material includes the third thermochemical heat storage material and the third carrier;

[0028] Preferably, the mass ratio of the third thermochemical heat storage material to the third carrier is (75-85):(25-15);

[0029] Preferably, the third thermochemical heat storage material includes at least one of CaO / Ca(OH)2, MgO / Mg(OH)2, and BaO / Ba(OH)2.

[0030] Preferably, the third carrier includes at least one of vermiculite, zeolite, or silicon carbide;

[0031] Furthermore, at least one of the following conditions must be met:

[0032] (1) The volume of the heat-releasing material inside the tank is ≤ 2 / 3 of the internal volume of the tank;

[0033] (2) A stirring device is provided inside the tank. Optionally, the stirring device is a linkage mechanical stirring device.

[0034] (3) The reactor also includes a top cover and a bottom cover, wherein the top cover is provided with an opening on the tank body and the bottom cover is provided with an opening at the bottom of the tank body;

[0035] The bottom cover is provided with a gas inlet, and the top cover is provided with a gas outlet;

[0036] Preferably, a second thermocouple is provided at the gas inlet and a third thermocouple is provided at the gas outlet.

[0037] Furthermore, this also includes electronic control panels;

[0038] The first thermocouple monitors the temperature inside the reactor in real time and feeds the temperature signal back to the electronic control panel. The electronic control panel then adjusts the output power of the microwave generator based on the received temperature signal.

[0039] Secondly, the present invention provides a method for charging a thermal storage and release material by directly heating the thermal storage and release material with microwaves.

[0040] Furthermore, at least one of the following conditions must be met:

[0041] (1) The heat storage and release material is a material that is heated and dehydrated to generate energy;

[0042] (2) The microwave transmission frequency is 900MHz to 10GHz, for example 2.45GHz, and the microwave output power is 0.5 to 100kW, preferably 0.6 to 20kW;

[0043] (3) Use renewable energy power or off-peak power to drive the microwave generator.

[0044] Furthermore, the mesh size of the porous wire mesh is smaller than that of the heat storage and release material.

[0045] Furthermore, the first thermocouple is installed in the gap between the blades of the stirring device, and the thermocouple is inserted laterally into the reactor during installation.

[0046] The thermochemical energy storage and release system controls the bed temperature at 300-600℃ during application.

[0047] Preferably, the energy release temperature is controlled at 300-400℃ to avoid excessively high temperatures that would hinder the hydration reaction.

[0048] Preferably, the charging temperature is controlled between 400 and 600°C.

[0049] The system of this invention is a closed system to avoid the influence of carbon dioxide. It is preferable to control the temperature at 400-500℃ for dehydration and energy charging. Due to the low temperature, the system has a high selectivity for materials and low cost.

[0050] A porous baffle is installed between two adjacent layers of heat storage and release materials, and the blades of the stirring device stir each layer.

[0051] In one possible design, the stirring device includes multiple sets of blades, each set corresponding to a layer of heat storage material. Optionally, the multiple sets of blades are fixed by screwing. During the assembly of the thermochemical energy storage system, the first set of blades can be placed in the tank first, followed by the addition of the lower layer of heat storage material, then the first layer of porous baffle can be added, and then the second set of blades and the third set of blades can be installed in sequence according to the above process.

[0052] Bed temperature refers to the temperature at different locations within a reactor along the radial or axial direction. Since the material is placed inside the reactor, its temperature is also the reactor bed temperature. In practical applications, more temperature sensors are needed to better monitor the reactor temperature. The previous diagram did not show a large number of temperature sensors for ease of understanding. For example, water vapor enters the reactor from the bottom, reacting with the lower layer of material before reacting upwards. According to the experimentally measured temperature distribution curve, the temperature at different axial and radial locations within the reactor varies at a given time point. Therefore, to accurately monitor the reactor temperature, multiple temperature sensors need to be installed along both the axial and radial directions.

[0053] Furthermore, multiple first thermocouples are provided.

[0054] Furthermore, the microwave generator is a magnetron.

[0055] The microwave transmission frequency and output power can be adjusted according to the corresponding energy storage application and the required amount of heat storage and release materials.

[0056] The technical solution of this invention has the following advantages:

[0057] 1. The thermochemical energy storage and release system of the present invention includes a reactor and a microwave generator and heat storage and release materials disposed in the reactor.

[0058] This invention charges the thermal storage material by directly applying microwaves instead of using electric heating or hot air flow. By utilizing microwave technology and volumetric heating methods (using microwaves to uniformly heat the material throughout the entire reactor volume), the charging response speed is significantly improved, the charging temperature is reasonably reduced, and the regeneration process of thermochemical energy storage is accelerated, thereby improving the overall efficiency and flexibility of the system.

[0059] 2. The tank body is designed with openings at both the top and bottom, and both openings are fitted with perforated wire mesh. The perforated wire mesh is designed to contain the heat storage and release material, ensuring that the heat storage and release material remains in the tank body during the reaction process, preventing it from falling to the bottom cover and from being blown out of the tank body by the rising steam flow.

[0060] 3. The mesh size of the porous wire mesh should not exceed twice the size of the heat storage and release material. Generally, the mesh size needs to be more than twice the size of the heat storage and release material particles for particles to pass through, because it is difficult for accumulated particles to pass perfectly through meshes of similar size.

[0061] 4. The size of the heat storage and release material is >5μm, and the mesh size is 5~10μm. Avoid the mesh being too small, which would hinder the effective flow of the reaction vapor. It can also hold smaller heat storage and release materials.

[0062] 5. The first thermocouple is a fiber optic thermocouple, whose material is not sensitive to microwaves, and can accurately measure the required temperature in an environment where microwaves are present.

[0063] 6. The heat storage and release materials are arranged in layers inside the tank, and the size of the heat storage and release materials gradually decreases from bottom to top.

[0064] During the system's energy release process, water vapor is introduced through the gas inlet of the bottom cover and gradually rises. Therefore, the lower layer of heat storage and release material is prone to significant volume expansion due to water absorption, leading to material compaction. This increases steam flow resistance and reduces the efficiency of steam contact and reaction with the unreacted upper layer of material. Therefore, this invention employs a layered filling of the heat storage and release material in the fixed-bed reactor. Larger particles help prevent agglomeration of the heat storage and release material in the lower and middle layers of the reactor, thereby promoting steam flow and reaction with as much heat storage and release material as possible. Simultaneously, the smaller upper layer of heat storage and release material has a higher specific surface area, allowing for better contact and reaction with water vapor and facilitating heat and mass transfer.

[0065] 7. The mass ratio of the first thermochemical thermal storage material to the first carrier in the lower layer is (50-65): (50-35); the mass ratio of the second thermochemical thermal storage material to the second carrier in the middle layer is (65-75): (35-25); and the mass ratio of the third thermochemical thermal storage material to the third carrier in the upper layer is (75-85): (25-15).

[0066] Because water vapor enters from the bottom of the reactor and is absorbed and reacted layer by layer by layer from bottom to top by the heat storage and release materials, the steam content in the bottom layer of the reactor will always be higher than that in the top layer. If the same reactive material is used in the bottom, middle, and top layers of the reactor, there will be a large gradient in the heat release and temperature at different locations within the reactor. In this invention, the content of the thermochemical heat storage material in the reactor gradually increases from bottom to top. This design avoids the problem that the upper layer of heat storage and release materials cannot react completely due to the small amount of steam, thus making better use of the materials. When the heat storage and release materials in each layer of the reactor can react more fully with the water vapor, the system can release more heat in one working cycle, and the bed temperature within the reactor will be more uniform.

[0067] 8. The volume of the heat storage material inside the tank should be ≤ 2 / 3 of the tank's internal volume. Specifically, when the tank is divided into layers, the volume of the heat storage material in each layer should be ≤ 2 / 3 of the tank's volume for that layer. This avoids damage to the tank caused by the heat storage material absorbing water and expanding in volume, while also reducing the degree of material compaction caused by volume expansion.

[0068] 9. The tank is equipped with a stirring device to further solve the problems of volume expansion and agglomeration of the heat storage and release materials in the energy storage and release cycle (>1000 cycles).

[0069] Preferably, a linkage-type mechanical agitator is installed in the reactor. Since the present invention can produce steam in one piece without setting up an additional heat exchange interface (such as a heat exchange coil) in the reactor, it is relatively convenient to install a ceramic-based linkage-type mechanical agitator in the reactor.

[0070] The thermochemical energy storage system of this invention has a high heat storage and release energy density (>300Wh / kg).

[0071] The theoretical heat of reaction for calcium oxide hydration and dehydration is relatively high, significantly exceeding the energy density of sensible and latent heat energy storage methods. However, in practical applications of calcium oxide hydration and dehydration reactions, problems such as reactant agglomeration, poor reactant contact, reactor compression, and increased flow resistance can prevent such thermochemical energy storage batteries from reaching or maintaining their theoretical heat storage and release energy density over multiple cycles. This invention can improve the cycle stability of such energy storage systems, enhance their energy efficiency and flexibility, making these systems more feasible and adaptable.

[0072] 11. Use renewable energy or inexpensive off-peak electricity to drive a microwave generator and enable microwaves to directly heat the heat storage material.

[0073] The thermochemical thermal energy storage system of this invention has many advantages, including higher energy density (up to 500 Wh / kg, compared to 50 Wh / kg and 100 Wh / kg for sensible and latent heat energy storage systems, respectively), and it can be used for both short-term and long-term energy storage (i.e., thermal energy storage on a daily, weekly, or quarterly basis) because energy loss during the storage and transportation of the energized material is negligible. Sensible and latent heat energy storage systems, on the other hand, are only suitable for short-term energy storage and require large amounts of insulation material.

[0074] Furthermore, this invention integrates the energy charging, energy release, and direct generation of hot steam in a thermochemical thermal storage system within a single reactor. During the energy extraction process, water vapor serves as both the working fluid for reaction and the heat extraction fluid, transferring heat and mass with the charged solid thermochemical reaction material. Therefore, no additional heat exchange interface for steam production is required. This results in high energy conversion efficiency.

[0075] The system of this invention can also be used to upgrade the temperature grade of waste heat, making it suitable for higher temperature application scenarios.

[0076] The thermochemical energy storage in this invention has an energy density greater than 300 Wh / kg, a small system size, and the charging and discharging processes are completed within the same reactor, eliminating the need to transport the heat storage and discharging materials when switching between charging and discharging modes. Furthermore, the energy storage materials that are charged via thermochemical reaction can be stored or transported at room temperature before the discharging process, without requiring extensive insulation treatment.

[0077] This invention can couple the charging process with renewable energy generation or smart meters to achieve the goal of saving electricity costs.

[0078] Compared to heating with electricity or hot air, microwave charging significantly reduces the thermochemical reaction temperature required for dehydration (by 150°C) and greatly shortens the time required for complete dehydration (by 50%). The lower dehydration temperature and shorter dehydration time improve energy recycling efficiency and facilitate system integration and material selection.

[0079] Furthermore, this invention utilizes novel heat storage and release materials (for endothermic / exothermic reactions) to further accelerate the energy storage and release process and extend the material's cycle life, such as composite materials based on Ca(OH)2 and vermiculite. Attached Figure Description

[0080] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0081] Figure 1 This is a schematic diagram of the thermochemical energy storage and release system of the present invention;

[0082] Figure 2 This is a schematic diagram of a porous wire mesh structure;

[0083] Figure 3 This is a schematic diagram illustrating the working principle of the energy release process in a thermochemical energy storage and release system.

[0084] Figure 4 A schematic diagram illustrating the working principle of the charging process of a thermochemical energy storage and release system;

[0085] Figure 5 This represents the time required for calcium hydroxide samples to be completely dehydrated when directly heated to different temperatures using microwaves.

[0086] Figure label:

[0087] 1-Reactor; 101-Tank body; 102-First porous wire mesh; 103-Second porous wire mesh; 104-Top cover; 105-Bottom cover; 2-Microwave generator; 3-Heat storage and release material; 4-Porous baffle; 5-Stirring device; 501-Blade; 6-First thermocouple; 7-Gas inlet; 8-Gas outlet; 9-First flange; 10-Second flange; 11-Electronic control panel. Detailed Implementation

[0088] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0089] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0090] The method for preparing the heat storage and release material used in this embodiment of the invention is as follows:

[0091] Calcium oxide powder and vermiculite particles were mixed at a target mass ratio. Distilled water was added to the mixture, and the mixture was stirred thoroughly to allow the calcium hydroxide solution and particles to penetrate into the micropores of the vermiculite. Vacuum filtration was then used to further promote the fusion of calcium hydroxide and vermiculite. The resulting slurry was then dried in a high-temperature furnace and subsequently dehydrated and decarburized in a muffle furnace at 950°C to obtain composite particles of calcium oxide and vermiculite.

[0092] Due to the high-temperature resistance of vermiculite, this composite material can be used not only in high-temperature closed systems but also in high-temperature open systems without having to consider the material oxidation and carbonization problems that may be encountered in high-temperature open systems.

[0093] Example 1

[0094] This embodiment provides a thermochemical energy storage and release system, such as Figure 1 , Figure 2 As shown, it includes a reactor 1 and a microwave generator 2 and a heat storage / release material disposed in the reactor 1.

[0095] The reactor 1 includes a tank 101, which has openings at the top and bottom. A first porous wire mesh 102 is provided at the top opening of the tank 101, and a second porous wire mesh 103 is provided at the bottom opening. The microwave generator 2 and the heat storage and release material 3 are both disposed inside the tank 101.

[0096] The heat storage and release material 3 is arranged in three layers: lower, middle and upper, inside the tank 101. A porous baffle 4 is provided between two adjacent layers of heat storage and release material 3 to prevent the upper heat storage and release material 3 from falling. The size of the heat storage and release material 3 gradually decreases from bottom to top.

[0097] In this embodiment, the mesh size of both the first porous wire mesh 102 and the second porous wire mesh 103 is 5μm. The size of the lower heat storage and release material is 1.5-3mm, the size of the middle heat storage and release material is 0.5-1.5mm, and the size of the upper heat storage and release material is 0.1-0.5mm.

[0098] The heights of the lower, middle, and upper layers are in a ratio of 1:1:1.

[0099] In this embodiment, the lower layer of thermal storage material comprises CaO / Ca(OH)2 and vermiculite, with a mass ratio of CaO / Ca(OH)2 (converted to CaO mass) to vermiculite of 50:50. The middle layer of thermal storage material comprises CaO / Ca(OH)2 and vermiculite, with a mass ratio of CaO / Ca(OH)2 (converted to CaO mass) to vermiculite of 75:25. The upper layer of thermal storage material comprises CaO / Ca(OH)2 and vermiculite, with a mass ratio of CaO / Ca(OH)2 (converted to CaO mass) to vermiculite of 85:15.

[0100] The volume of each layer of heat storage material 3 inside tank 101 is ≤ 2 / 3 of the internal volume of the tank 101 in that layer.

[0101] A stirring device 5 is installed inside the tank 101. In this embodiment, the stirring device 5 is a linkage-type mechanical stirring device including three sets of blades 501, which are respectively installed in the lower, middle and upper layers of heat storage and release materials.

[0102] The thermochemical energy storage and release system also includes a first thermocouple 6 installed in the tank 101; in this embodiment, the first thermocouple 6 is a fiber optic thermocouple, and three first thermocouples 6 are installed, respectively in the upper, middle and lower layers of the tank 101.

[0103] The reactor 1 also includes a top cover 104 and a bottom cover 105. The top cover has an opening on the tank body 101, and the bottom cover has an opening at the bottom of the tank body 101. The bottom cover 105 is provided with a gas inlet 7, and the top cover 104 is provided with a gas outlet 8.

[0104] A second thermocouple is installed at gas inlet 7 and a third thermocouple is installed at gas outlet 8, which are used to monitor the inlet and outlet steam temperatures, respectively.

[0105] In this embodiment, the tank body 101, the first porous wire mesh 102, and the top cover 104 are connected and pressed tightly sealed by the first flange 9, and the tank body 101, the second porous wire mesh 103, and the bottom cover 105 are connected and pressed tightly sealed by the second flange 10. The flange pressing setting is to meet the requirement of using the reactor 1 in a high-pressure closed system (10 bar pressure).

[0106] The thermochemical energy storage and release system also includes an electronic control panel 11; the first thermocouple 6 monitors the temperature of the reactor 1 in real time and feeds back the temperature signal to the electronic control panel 11, which adjusts the output power of the microwave generator 2 according to the received temperature signal.

[0107] During application, the bed temperature is controlled at 300-600℃ to ensure the safe and effective continuous operation of the entire charging and discharging process.

[0108] The working principle of the thermochemical energy storage system in this embodiment is as follows: Figure 3 , Figure 4 As shown, it is:

[0109] Energy charging process: The electric power drives the microwave generator to cover the entire heat storage material with microwaves, directly heating it with microwaves. Ca(OH)2 loses water and is converted into CaO, and electrical energy is converted into chemical energy for storage.

[0110] Energy release process: Cold steam or steam preheated by waste heat (100-200℃) enters from the bottom cover of the reactor and comes into contact with the heat storage material. CaO undergoes a water absorption and exothermic reaction, converting chemical energy into thermal energy. In this process, the steam reacts first with the material in the lower layer of the reactor and then reacts with the material above it layer by layer from bottom to top. The steam that does not react with the reacting material is heated by the heat released by the water absorption and exothermic reaction along its flow path, becoming superheated steam at a higher temperature, and finally flows out from the top cover of the reactor. This superheated steam can then be directly supplied to users who need steam or heat energy.

[0111] Application Example 1

[0112] A factory involving distillation processes requires a peak steam supply every 1-2 hours throughout the day, posing challenges to the operation of the main boiler and its electricity consumption. However, by using the thermochemical energy storage system of this invention, the burden on the main boiler can be alleviated, significantly reducing operating and maintenance costs.

[0113] Specifically, during peak steam demand periods, cold steam or preheated steam (using waste heat) is introduced into the thermochemical energy storage system. The superheated steam is generated through the water absorption and exothermic reaction of the thermochemical energy storage material and supplied to the distillation process along with the steam generated by the main boiler, thus significantly reducing the steam production burden on the main boiler. After the 1-2 hour peak steam and electricity demand period ends, the subsequent 1-2 hour off-peak demand period allows for microwave-driven dehydration and recharging of the thermochemical energy storage material, preparing it for the next peak steam demand period.

[0114] It is worth noting that traditional thermochemical energy storage systems using electric heating or high-temperature gas heating cannot complete recharging in such a short time. Furthermore, another advantage of the aforementioned thermochemical energy storage system is that it eliminates the need for opening the lid for refueling or moving equipment during multiple energy storage releases and steam production cycles throughout the day.

[0115] The thermochemical energy storage system of the present invention is more flexible in transient or intermittent applications because it can be rapidly charged by microwave and volume heating.

[0116] Application Example 2

[0117] The paper industry requires large amounts of high-temperature steam, such as during the mixing of raw materials to make pulp, and in the later stages of dehumidification, drying, and hardening of the pulp into paper on steam-heated drums. According to 2005 statistics, pulp, paper, and paperboard mills accounted for approximately 15% of total energy consumption in the US manufacturing sector, with steam production accounting for 43% of that energy consumption. Currently, paper mills typically use boilers burning biomass or fossil fuels to produce steam. Furthermore, because the papermaking process generates a large amount of high-temperature steam, waste steam can be collected through condensation and recycled as waste heat. Therefore, applying the thermochemical heat storage system of this invention to papermaking production is a potential option.

[0118] Specifically, the recovered waste steam or waste hot water can be fed into the thermochemical reaction tank of this invention, where a water absorption and exothermic reaction generates superheated steam. This superheated steam is then combined with the steam generated by the main boiler and supplied to processes requiring steam, such as pulp mixing and paper drying. In this way, the recycling of waste steam and wastewater reduces overall water consumption and waste, while the superheated steam produced by the thermochemical energy storage system reduces the electricity and water load on the main boiler, and simultaneously reduces carbon emissions from burning fossil fuels. However, since the papermaking process requires a continuous steam supply, the thermochemical energy storage system applied to the papermaking industry can adopt a multi-tank system. Once the reaction materials in one tank have completed their energy release and steam supply, they enter the microwave heating and charging process, while simultaneously connecting to another fully charged reaction tank to continue supplying energy and steam to the papermaking process.

[0119] It is worth noting that using microwave heating to dehydrate and energize the reaction materials can significantly shorten the required time. Compared to traditional electric heating or high-temperature gas heating systems, the number of reaction vessels and the amount of reaction materials used for alternating steam production are much smaller.

[0120] Application Example 3

[0121] During off-peak hours for electricity and steam, this system converts inexpensive electricity into high-quality heat energy and stores it (at 500 degrees Celsius). During peak hours, the system directly produces high-temperature steam and supplies it to industrial processes that require it (such as industrial drying processes), thereby achieving peak shaving and valley filling of steam demand and related electricity consumption, ensuring full utilization of resources and guaranteeing the stable operation of industrial processes.

[0122] Application Example 4

[0123] Compared to hot water storage tanks, high-temperature sensible heat storage devices, and medium- and low-temperature phase change heat storage devices, this system significantly improves heat storage density (>1000 J / g), thus making it widely applicable in building heating and hot water supply applications where space requirements are stringent. It can be used in conjunction with traditional coal-fired boilers or natural gas wall-hung boilers, utilizing off-peak electricity or renewable energy sources to store heat energy at night, which is then used to supplement the daytime hot water supply and heating. Compared to heating entirely with electricity or electric water heaters, using this heat storage device for heating and hot water supply can significantly reduce heating costs by taking advantage of peak-valley electricity price differences.

[0124] Test case

[0125] 1. Calcium hydroxide is heated using different heating methods:

[0126] A 2.5g sample of pure calcium hydroxide requires 60 minutes to dehydrate when heated to 500℃ in an electrically heated high-temperature furnace.

[0127] A 2g sample of pure calcium hydroxide could not be dehydrated when heated to 400℃ in an electrically heated high-temperature furnace.

[0128] 2.5g of heat storage and release material (in which the mass ratio of calcium hydroxide to vermiculite is 75:25) can be completely dehydrated within 20 minutes when heated to 400℃ by microwave.

[0129] Compared with traditional thermochemical energy storage systems that charge energy through electric heating of high-temperature furnaces or high-temperature airflow, using microwaves to directly heat and charge the energy storage material can not only increase the charging rate but also reduce the temperature required for charging, thereby greatly improving the flexibility and adaptability of the thermochemical energy storage system in this invention in industrial production applications.

[0130] 2. The time required for 2.5g of heat storage and release material (in which the mass ratio of calcium hydroxide to vermiculite is 75:25) to completely dehydrate when heated to different temperatures by a microwave oven. Figure 5 It can be seen that when the temperature is above 400℃, the time for complete dehydration is significantly shortened.

[0131] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A thermo-chemical energy storage system, characterized by, This includes the reactor and the microwave generator and heat storage / release materials installed within the reactor; The reactor includes a tank with openings at the top and bottom. Both the top and bottom openings of the tank are provided with porous wire mesh. The microwave generator and the heat storage material are both housed inside the tank. The mesh size of the porous wire mesh should not exceed twice the size of the heat storage material.

2. The thermo-chemical energy storage system of claim 1, wherein, It also includes a first thermocouple disposed in the tank, wherein one or more of the first thermocouples are disposed.

3. The thermo-chemical energy storage system of claim 2, wherein, The first thermocouple is a fiber optic thermocouple.

4. The thermo-chemical energy storage system of claim 1, wherein, The heat storage and release materials are arranged in layers inside the tank, with the size of the heat storage and release materials gradually decreasing from bottom to top.

5. The thermo-chemical energy storage system of claim 4, wherein, The heat storage and release material is arranged in three layers inside the tank: a lower layer, a middle layer, and an upper layer. The size of the heat storage and release material in the lower layer is 1.5~3mm, the size of the heat storage and release material in the middle layer is 0.5~1.5mm, and the size of the heat storage and release material in the upper layer is 0.1~0.5mm.

6. The thermo-chemical energy storage system of claim 5, wherein, The heat storage and release material satisfies at least one of the following conditions: (1) The lower layer heat storage and release material includes a first thermochemical heat storage material and a first carrier; (2) The intermediate layer heat storage and release material includes the second thermochemical heat storage material and the second carrier; (3) The upper heat storage and release materials include the third thermochemical heat storage material and the third carrier.

7. The thermochemical energy storage and release system according to claim 6, characterized in that, At least one of the following conditions must be met: (1) The mass ratio of the first thermochemical heat storage material to the first carrier is (50~65):(50~35); (2) The first thermochemical heat storage material includes at least one of CaO / Ca(OH)2, MgO / Mg(OH)2, and BaO / Ba(OH)2; (3) The first carrier includes at least one of vermiculite, zeolite or silicon carbide; (4) The mass ratio of the second thermochemical heat storage material to the second carrier is (65~75):(35~25); (5) The second thermochemical heat storage material includes at least one of CaO / Ca(OH)2, MgO / Mg(OH)2, and BaO / Ba(OH)2; (6) The second carrier includes at least one of vermiculite, zeolite or silicon carbide; (7) The mass ratio of the third thermochemical heat storage material to the third carrier is (75~85):(25~15); (8) The third thermochemical heat storage material includes at least one of CaO / Ca(OH)2, MgO / Mg(OH)2, and BaO / Ba(OH)2; (9) The third carrier includes at least one of vermiculite, zeolite or silicon carbide.

8. The thermochemical energy storage and release system according to claim 1, characterized in that, At least one of the following conditions must be met: (1) The volume of the heat-releasing material stored in the tank is ≤ 2 / 3 of the internal volume of the tank; (2) The tank is equipped with a stirring device; (3) The reactor further includes a top cover and a bottom cover, wherein the top cover is provided with an opening on the tank body and the bottom cover is provided with an opening at the bottom of the tank body; The bottom cover has a gas inlet, and the top cover has a gas outlet.

9. The thermochemical energy storage and release system according to claim 8, characterized in that, A second thermocouple is installed at the gas inlet. And / or, A third thermocouple is installed at the gas outlet.

10. The thermochemical energy storage and release system according to claim 1, characterized in that, It also includes electronic control panels; The first thermocouple monitors the temperature inside the reactor in real time and feeds the temperature signal back to the electronic control panel. The electronic control panel then adjusts the output power of the microwave generator based on the received temperature signal.

11. A method for charging a thermal storage material, characterized in that, The thermochemical energy storage and release system according to any one of claims 1-10 employs microwave direct heating of the heat storage and release material.

12. The method for charging thermal storage and release materials according to claim 11, characterized in that, At least one of the following conditions must be met: (1) The heat storage and release material is a material that is heated and dehydrated to generate energy; (2) The microwave transmission frequency is 900 MHz to 10 GHz, and the microwave output power is 0.5 to 100 kW; (3) Use renewable energy power or off-peak power to drive the microwave generator.

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