A thermo-chemical energy storage system and method based on nano-bubble reinforcement

Abstract

The application discloses a kind of based on nano bubble intensification's thermochemical energy storage system and method, including nano bubble generator, thermochemical reactor, circulating drive unit and gas source supply unit, wherein, gas source supply unit's export is connected with the gas inlet of nano bubble generator, the liquid outlet of nano steam package generator is connected with the liquid inlet of thermochemical reactor, and the liquid outlet of thermochemical reactor is connected with the liquid inlet of nano bubble generator by circulating drive unit, and the system and method are higher in heat transfer efficiency, can inhibit energy storage material sintering agglomeration simultaneously.

Description

Technical Field

[0001] This invention belongs to the field of energy storage technology and relates to a thermochemical energy storage system and method based on nanobubble enhancement. Background Technology

[0002] The rate of solid-gas thermochemical reactions largely depends on the diffusion and transport efficiency of gaseous reactants into the solid material. In existing reactors, gaseous reactants mainly permeate into the solid material layer through macroscopic pore channels. This long diffusion path and high resistance result in uneven gas concentration distribution within the reactor, hindering the full participation of deep solid materials in the reaction. For example, in Mg(OH)₂ / MgO energy storage systems, uneven water vapor diffusion leads to a thermal storage efficiency of only about 70%. Calcium-based thermochemical energy storage materials also face significant challenges in reactor structural design during long-term cycling.

[0003] Most thermochemical energy storage materials have low thermal conductivity (typically less than 1 W / (m·K)), which can easily lead to localized overheating or undercooling during the storage / release reaction process, resulting in uneven reaction rates. Hydrated salt materials also suffer from significant problems of low thermal conductivity and low conversion rate during energy storage.

[0004] Thermochemical energy storage materials are prone to sintering and particle agglomeration during high-temperature cycling, leading to a decrease in specific surface area, reduced reactivity, and decreased energy storage density. Calcium-based materials are particularly susceptible to sintering deactivation during long-term cycling, which is more pronounced under solar irradiation. Hydrated salts and metal hydrides also exhibit similar problems, ultimately resulting in poor cycling stability. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a thermochemical energy storage system and method based on nanobubble reinforcement. This system and method have high heat transfer efficiency and can suppress the sintering and agglomeration of energy storage materials.

[0006] To achieve the above objectives, this invention discloses a thermochemical energy storage system enhanced by nanobubbles, comprising a nanobubble generator, a thermochemical reactor, a circulation drive unit, and a gas supply unit. The outlet of the gas supply unit is connected to the inlet of the nanobubble generator, the liquid outlet of the nanobubble generator is connected to the inlet of the thermochemical reactor, and the outlet of the thermochemical reactor is connected to the inlet of the nanobubble generator via the circulation drive unit.

[0007] Furthermore, the circulation drive unit includes a circulation pipeline and a circulation pump, and the outlet of the thermochemical reactor is connected to the inlet of the nanobubble generator via the circulation pipeline and the circulation pump.

[0008] Furthermore, the number of thermochemical reactors is one or more, and the thermochemical reactors are connected in parallel or in series.

[0009] Furthermore, a gas flow controller is provided at the outlet of the gas supply unit.

[0010] Furthermore, it also includes a temperature control unit, which includes a heating element and a cooling element. The heating element is used to provide the heat required for heat storage to the thermochemical reactor, and the cooling element is used to absorb the heat released by the thermochemical reactor.

[0011] Furthermore, the nanobubble generator is also equipped with a bubble size control module for regulating the size of the air drum output by the nanobubble generator.

[0012] Furthermore, the nanobubble generator uses hydraulic cavitation, ultrasonic cavitation, pressurized dissolved gas release, or electrolysis to generate nanobubbles.

[0013] Furthermore, temperature sensors, pressure sensors, flow meters, and / or gas concentration detectors are installed on the circulation pipeline.

[0014] This invention discloses a thermochemical energy storage method based on nanobubbles, and a thermochemical energy storage system based on nanobubbles, comprising the following steps: In energy storage mode, the heating element is activated to heat the thermochemical reactor to the endothermic reaction temperature; Start the circulation pump and nanobubble generator to make the working fluid containing nanobubbles circulate in the system. When the gaseous reactants in the nanobubble working fluid come into contact with the surface of the energy storage material, they participate in the endothermic reaction by utilizing the high interfacial density of the nanobubbles, and store the heat in the energy storage material in the form of chemical energy until the energy storage material completes the reaction or reaches the predetermined energy storage capacity. In the energy release mode, heating is stopped and cooling elements are activated, along with the circulation pump and nanobubble generator, causing the nanobubble working fluid to circulate. The gaseous reactants in the nanobubble working fluid trigger / participate in the exothermic reaction of the energy storage material, releasing the stored chemical energy and converting it into heat energy for recovery.

[0015] Furthermore, the average diameter of the steam drum in the nanobubble working fluid is 50-1000 nm.

[0016] The present invention has the following beneficial effects: The nanobubble-enhanced thermochemical energy storage system and method of this invention introduces a nanobubble generator into the field of thermochemical energy storage for the first time. Utilizing the high interfacial density and excellent stability of nanobubbles, it significantly enhances the mass and heat transfer efficiency in gas-solid reactions, overcoming the common bottleneck of diffusion limitation in traditional technologies. Furthermore, the micro-turbulence effect of the nanobubble working fluid suppresses the sintering and agglomeration of energy storage materials, extending the system's cycle life and improving cycle stability. The system features a compact structure, high modularity, and strong versatility, compatible with various energy storage material systems such as hydrated salts, hydroxides, metal hydrides, and carbonates, and covers applications across the entire temperature range from low to high temperatures, facilitating large-scale deployment. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a structural diagram of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0021] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0022] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0023] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0024] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0026] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0027] refer to Figure 1The thermochemical energy storage system based on nanobubble enhancement described in this invention includes: Nanobubble generator: Used to generate working fluids containing dispersed nano-sized bubbles in liquid media; Thermochemical reactor: The interior is filled or equipped with solid thermochemical energy storage material and is in fluid communication with a nanobubble generator; Circulation drive unit: connected to the reactor unit and / or generator unit, driving the working fluid to circulate within the system; Temperature control unit: used to control the temperature of the thermochemical reactor to achieve heat storage and heat release operations; Gas supply unit: Connected to the nanobubble generator, it provides the gas medium for generating nanobubbles.

[0028] The nanobubble working fluid generated by the nanobubble generator is fed into the thermochemical reactor. During the contact with the solid energy storage material, the high interfacial density of the nanobubbles significantly enhances the mass and heat transfer between the gas, solid, and liquid phases.

[0029] In this embodiment, the nanobubble generator generates nanobubbles using any one or more of the following principles: hydraulic cavitation (such as Venturi tube type, porous membrane type), ultrasonic cavitation, pressurized dissolved gas release, electrolysis, or a combination thereof.

[0030] Among them, the porous ceramic membrane method has a narrower bubble size distribution, with an average bubble diameter of 100-200 nm, and a zeta potential that can reach below -40 mV. It also exhibits good dispersion stability in the aqueous phase.

[0031] The nanobubble generator is also equipped with a bubble size control module, which controls the average diameter (preferably in the range of 50-1000 nm) and concentration (preferably in the range of 10 nm) of the nanobubbles by adjusting operating parameters (such as gas pressure, liquid flow rate, membrane pore size, ultrasonic frequency, etc.). 7 -10 10 (units / mL).

[0032] In this embodiment, the thermochemical reactor may adopt any of the following structural forms: Fixed-bed reactor: The interior is filled with granular or blocky solid energy storage materials. The nanobubble working fluid is introduced from the bottom or side wall of the fixed-bed reactor, flows through the material bed, and is discharged from the top. Fluidized bed reactor: Nanobubble working fluid is used as a fluidizing medium to fluidize solid energy storage materials, significantly increasing the gas-solid contact area; Plate or honeycomb reactors: Energy storage material is loaded on the surface of the reaction plate or honeycomb channel, and the working fluid flows through the channel surface to react; Sieve plate reactor: The sieve plate structure is used to improve fluid distribution and heat and mass transfer conditions.

[0033] In this embodiment, the circulation drive unit is preferably a circulation pump, which is connected between the liquid inlet end of the nanobubble generator and the outlet end of the thermochemical reactor to form a closed-loop circulation loop for the working fluid. A temperature sensor, a pressure sensor, a flow meter, and / or a gas concentration detector are installed on the circulation loop.

[0034] In this embodiment, the temperature control unit includes heating elements (such as electric heaters, electromagnetic induction heaters, steam heating jackets, etc.) and cooling elements (such as cooling water jackets, air-cooled radiators, etc.), as well as a temperature sensor and a temperature controller, forming a closed-loop temperature control system. The heating elements are used to provide the reactor with the heat required for heat storage, and the cooling elements are used to absorb the heat released by the exothermic reaction.

[0035] In this embodiment, the gas supply unit includes a gas source (such as a gas storage tank, gas generator, or external pipeline) and a gas flow controller, which provides a specific gas medium to the nanobubble generator as needed. The gas medium includes, but is not limited to, one or more mixtures of air, oxygen, nitrogen, carbon dioxide, hydrogen, water vapor, and argon, as well as mixtures of the above gases with additives.

[0036] In this embodiment, the gas outlet of the gas supply unit is connected to the air inlet of the nanobubble generator, the liquid outlet of the nanobubble generator is connected to the liquid inlet of the thermochemical reactor, and the liquid outlet of the thermochemical reactor is connected to the liquid inlet of the nanobubble generator via a circulation pipeline and a circulation pump.

[0037] In this embodiment, the number of thermochemical reactors is one or more, and the thermochemical reactors are connected in parallel or in series to achieve flexible expansion of energy storage capacity and power. Each thermochemical reactor can operate independently or collaboratively.

[0038] The thermochemical energy storage method based on nanobubble enhancement described in this invention includes an energy storage mode and an energy release mode: Energy storage mode: The heating element of the temperature control unit is activated to raise the temperature of the thermochemical reactor to the endothermic reaction temperature; Start the circulation pump and nanobubble generator to circulate the working fluid containing nanobubbles in the system; When gaseous reactants (such as O2, H2O, etc.) in the nanobubble working fluid come into contact with the surface of the energy storage material, they rapidly participate in the endothermic reaction by utilizing the high interfacial density of the nanobubbles, storing the heat in the energy storage material in the form of chemical energy. It continues to operate until the energy storage material completes its reaction or reaches the predetermined energy storage capacity.

[0039] Energy release mode: Stop heating and activate cooling elements, or use natural heat dissipation to adjust the temperature of the thermochemical reactor; Start the circulation pump and nanobubble generator to circulate the nanobubble working fluid; The gaseous reactants in the nanobubble working fluid trigger / participate in the exothermic reaction of the energy storage material, releasing the stored chemical energy and converting it into thermal energy; The released heat is recovered through a heat exchange unit and used by the external heat-consuming end. Continue running until the exothermic reaction is essentially complete.

[0040] Example 1 A thermochemical energy storage system enhanced by nanobubbles was constructed, using MgSO4·7H2O / MgSO4 as the energy storage material. The nanobubble generator employed a Venturi tube hydraulic cavitation type, with deionized water as the liquid medium. A water vapor-air mixture was supplied as the gas source. The thermochemical reactor was a sieve plate fixed bed filled with MgSO4 particles loaded on activated alumina.

[0041] During energy storage, the thermochemical reactor is heated to 120-150℃ by an electric heater, and the nanobubble generator is activated to produce water vapor-containing nanobubbles (average diameter 200 nm, concentration 2×10⁻⁶). 9 The working fluid (number of nanobubbles per mL) circulates through the bed, causing MgSO4·7H2O to dehydrate and convert to MgSO4. During energy release, the temperature is lowered to 25-40℃, and water vapor nanobubbles are introduced to rehydrate MgSO4, generating MgSO4·nH2O and releasing heat.

[0042] Experimental results show that, after adopting the present invention, the temperature distribution uniformity in the thermochemical reactor is improved by about 70%, and the energy storage rate is increased by about 45%.

[0043] Example 2 The MgH2 / Mg system is employed, and the nanobubble generator utilizes a high-pressure dissolved gas release type, with heat transfer oil as the liquid medium. High-purity hydrogen is the gas source. The thermochemical reactor is a shell-and-tube type, with internally connected inner and outer heat exchange tube bundles. During hydrogen release and heat storage, the temperature is raised to 350–400°C, and hydrogen nanobubbles (average diameter 100 nm) are introduced to accelerate the endothermic decomposition of MgH2. During hydrogen absorption and heat release, the temperature is lowered to 50–80°C, and hydrogen nanobubbles are used to promote the rapid generation of MgH2 and release heat.

[0044] The experimental results show that the reaction rate is increased by about 35% compared with the conventional MgH2 thermal storage system.

[0045] Example 3 Using Al / Mn / Ce co-doped calcium-based materials, the energy storage density retention rate can reach over 90% after 1000 cycles at 800℃. The carbonation exothermic reactor can be directly connected to a supercritical CO2 Brayton cycle power generation unit, and the overall power generation efficiency of the system is expected to reach over 32%.

[0046] Example 4 For the Mg(OH)₂ / MgO energy storage system, a pressure-self-balancing thermochemical cascade thermal storage architecture is adopted, coupling thermochemical energy storage with high-pressure hot water thermal storage to form a cascade thermal storage system. Compared with the conventional Mg(OH)₂ / MgO system, the thermal storage efficiency of this system can be increased by up to 28.17% from approximately 70%. A nanobubble generator (porous ceramic membrane type) further enhances the mass transfer efficiency of the dehydration and hydration two-step reactions, which is expected to shorten the single-step reaction time by 25%-35%.

[0047] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0048] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0049] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A thermochemical energy storage system based on nanobubbles, characterized in that, It includes a nanobubble generator, a thermochemical reactor, a circulation drive unit, and a gas supply unit. The outlet of the gas supply unit is connected to the inlet of the nanobubble generator, the liquid outlet of the nanobubble generator is connected to the inlet of the thermochemical reactor, and the outlet of the thermochemical reactor is connected to the inlet of the nanobubble generator via the circulation drive unit.

2. The thermochemical energy storage system based on nanobubble enhancement according to claim 1, characterized in that, The circulation drive unit includes a circulation pipeline and a circulation pump. The outlet of the thermochemical reactor is connected to the inlet of the nanobubble generator via the circulation pipeline and the circulation pump.

3. The thermochemical energy storage system based on nanobubble enhancement according to claim 1, characterized in that, The number of thermochemical reactors is one or more, and the thermochemical reactors are connected in parallel or in series.

4. The thermochemical energy storage system based on nanobubble enhancement according to claim 1, characterized in that, A gas flow controller is installed at the outlet of the gas supply unit.

5. The thermochemical energy storage system based on nanobubble enhancement according to claim 2, characterized in that, It also includes a temperature control unit, which includes a heating element and a cooling element. The heating element is used to provide the heat required for heat storage to the thermochemical reactor, and the cooling element is used to absorb the heat released by the thermochemical reactor.

6. The thermochemical energy storage system based on nanobubble enhancement according to claim 1, characterized in that, The nanobubble generator is also equipped with a bubble size control module for regulating the size of the air drum output by the nanobubble generator.

7. The thermochemical energy storage system based on nanobubble reinforcement according to claim 1, characterized in that, The nanobubble generator uses hydraulic cavitation, ultrasonic cavitation, pressurized dissolved gas release, or electrolysis to generate nanobubbles.

8. The thermochemical energy storage system based on nanobubble enhancement according to claim 2, characterized in that, Temperature sensors, pressure sensors, flow meters, and / or gas concentration detectors are installed on the circulation pipeline.

9. A thermochemical energy storage method based on nanobubble enhancement, characterized in that, The thermochemical energy storage system based on nanobubble enhancement as described in claim 5 includes the following steps: In energy storage mode, the heating element is activated to heat the thermochemical reactor to the endothermic reaction temperature; Start the circulation pump and nanobubble generator to make the working fluid containing nanobubbles circulate in the system. When the gaseous reactants in the nanobubble working fluid come into contact with the surface of the energy storage material, they participate in the endothermic reaction by utilizing the high interfacial density of the nanobubbles, and store the heat in the energy storage material in the form of chemical energy until the energy storage material completes the reaction or reaches the predetermined energy storage capacity. In the energy release mode, heating is stopped and cooling elements are activated, along with the circulation pump and nanobubble generator, causing the nanobubble working fluid to circulate. The gaseous reactants in the nanobubble working fluid trigger / participate in the exothermic reaction of the energy storage material, releasing the stored chemical energy and converting it into heat energy for recovery.

10. The thermochemical energy storage method based on nanobubble enhancement according to claim 9, characterized in that, The average diameter of the steam drum in the nanobubble working fluid is 50-1000 nm.

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