Thermochemical heat storage and release system and method and application thereof

Abstract

The invention discloses a thermochemical heat storage and release system and method and application thereof. The thermochemical heat storage and release system comprises an energy storage module and an energy release module; the energy storage module comprises a first hydroxide bin, an oxide bin, a decomposition reactor, a first gas-solid separator, a first solid-liquid heat exchanger, a heating water tank, a heat storage water tank and a water supplementing pipeline; the decomposition reactor is used for the reaction of decomposing hydroxide into oxide and water; the energy release module comprises a synthesis reactor, a second gas-solid separator, a second solid-liquid heat exchanger, a second hydroxide bin and a cooling water pipeline; the synthesis reactor is used for synthesis reaction of oxide and water. The system has high system heat efficiency and heat storage efficiency, long-time energy storage is achieved, meanwhile, high-temperature heat and low-temperature heat can be provided, and the provided heat can be easily consumed.

Description

Technical Field

[0001] The invention relates to a thermochemical heat storage and release system and method and applications thereof. Background Art

[0002] With the development of electrification and automation, users' electricity demand increases year by year. As the proportion of renewable energy continues to grow, the peak-valley load difference of the power grid is becoming more and more serious. In order to improve the stability of the power grid and maintain the balance of the power system, it is necessary to take corresponding peak-shaving measures during the operation of the power grid. Conventional peak-shaving methods include peak-shaving of thermal power units, pumped energy storage, compressed air energy storage, solid heat storage and battery energy storage.

[0003] Pure water heat storage has the advantages of low cost and low technical difficulty, but it also has the disadvantages of occupying a huge space and being in a demanding geographical location. At the same time, pure water heat storage has the disadvantages of low temperature and a single heat user. When used on a large scale, it can only be used for heating or cooling. When used on a small scale, it can be used for thermal power peak regulation, but due to the low heat storage density, the peak regulation capacity is quite limited.

[0004] Pure gas-solid thermochemical energy storage also has certain drawbacks. Taking the CaO / Ca(OH)2 thermochemical energy storage system as an example, a large amount of high-temperature water vapor will be generated during the energy storage stage. The heat carried by these high-temperature water vapor accounts for nearly 40% of the entire energy storage system, and the thermal energy of high-temperature water vapor is difficult to store directly, so only absorption and indirect storage can be considered. The period when energy storage is needed is precisely the period when there is excess electricity and energy is not easy to absorb. Indirect storage is difficult, and direct abandonment will greatly reduce the system's heat storage efficiency. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the defects of low heat storage efficiency, inability to store energy for a long time, and low energy conversion efficiency in the prior art, and to provide a thermochemical heat storage and release system and method and its application. The present invention has high system thermal efficiency and heat storage efficiency, and realizes long-term energy storage, while providing high-temperature heat and low-temperature heat, and the heat provided is easily absorbed.

[0006] The present invention solves the above-mentioned technical problems through the following technical methods:

[0007] The present invention provides a thermochemical heat storage and release system, which includes an energy storage module and an energy release module;

[0008] The energy storage module includes a first hydroxide silo, a decomposition reactor, a first gas-solid separator, a first solid-liquid heat exchanger, an oxide silo, a heating water tank, a hot water storage tank and a water supply pipeline; the first hydroxide silo is connected to the decomposition reactor, the first hydroxide silo is used to provide calcium hydroxide, magnesium hydroxide or ferrous hydroxide, and the decomposition reactor is used for the reaction of calcium hydroxide, magnesium hydroxide or ferrous hydroxide decomposing into oxides and water; the feed port of the first gas-solid separator and the solid phase outlet of the first gas-solid separator are respectively connected to the discharge port of the decomposition reactor and the first solid-liquid heat exchanger, the gas phase outlet of the first gas-solid separator is connected to the heating water tank and the hot water storage tank in turn, the water supply pipeline is connected to the first solid-liquid heat exchanger to realize indirect heat exchange of oxides, and the discharge port of the first solid-liquid heat exchanger is connected to the oxide silo; the oxide silo is used to store calcium oxide, magnesium oxide or ferrous oxide;

[0009] The energy release module includes a synthesis reactor, a second gas-solid separator, a second solid-liquid heat exchanger, a second hydroxide bin and a cooling water pipeline; the oxide bin is connected to the solid phase feed port of the synthesis reactor; the synthesis reactor is also provided with a water inlet pipeline for providing the raw materials required for the synthesis reaction; the synthesis reactor is used for the synthesis reaction of the oxide from the oxide bin and water; the discharge port of the synthesis reactor is connected to the feed port of the second gas-solid separator, and the water vapor outlet of the second gas-solid separator is connected to the synthesis reactor as a supplementary raw material for the synthesis reaction; the solid phase outlet of the second gas-solid separator is connected to the second solid-liquid heat exchanger and the second hydroxide bin in sequence; the cooling water pipeline is connected to the second solid-liquid heat exchanger and the synthesis reactor in sequence to realize heat exchange of hydroxide and synthesis reaction process respectively.

[0010] Those skilled in the art should understand that the second hydroxide material bin is used to store calcium hydroxide, magnesium hydroxide or ferrous hydroxide generated in the energy release module.

[0011] In the present invention, preferably, in the energy storage module, the decomposition reactor includes a heater for providing heat for the decomposition reaction of calcium hydroxide, magnesium hydroxide or ferrous hydroxide.

[0012] The heater can generally be connected to a power supply module to provide energy to be stored in the form of electrical heating.

[0013] Preferably, the power supply module includes one or more of a wind power module, a photovoltaic module and a power generation module. During the valley power period, the electric energy / heat energy is stored through the decomposition reaction of the hydroxide in the decomposition reactor; during the peak power period, the stored heat is released and supplied to users.

[0014] In the present invention, preferably, a booster pump is provided on the pipeline between the heating water tank and the hot water storage tank.

[0015] In the present invention, preferably, a steam injector is provided at the feed inlet of the heating water tank for introducing water vapor from the first gas-solid separator into the heating water tank.

[0016] In the present invention, preferably, the water outlet of the first solid-liquid heat exchanger is connected to the heating water tank, so as to supply the outlet water in the first solid-liquid heat exchanger to the heating water tank.

[0017] In the present invention, preferably, the energy storage module further includes a water replenishment tank and a first water replenishment pump, and the water replenishment pipeline is connected to the water replenishment tank through the first water replenishment pump before being connected to the first solid-liquid heat exchanger.

[0018] Among them, preferably, in the energy storage module, the hot water outlet of the heat storage tank is used to connect to the hot water input pipeline of the heat consumption module, and is connected to the water supply pipeline of the first solid-liquid heat exchanger through the cooling water output pipeline of the heat consumption module, forming a hot water-cold water-hot water circulation loop.

[0019] Preferably, a drain port is provided on the pipeline between the cooling water output pipeline of the heat consumption module and the water supply pipeline of the first solid-liquid heat exchanger; after multiple cycles, the water quality in the heat exchange pipeline will deteriorate and needs to be discharged and supplemented with fresh water.

[0020] Preferably, the heat consumption module includes a heating system and / or a cooling system; more preferably, the cooling system includes a lithium bromide refrigerator.

[0021] In the present invention, the first solid-liquid heat exchanger may be a built-in or external partition wall heat exchanger.

[0022] In the present invention, preferably, in the energy release module, an electric heating steam generator is provided on the water inlet pipe.

[0023] In the present invention, preferably, the energy release module further comprises a water replenishment system, and the water replenishment system is connected to the gas phase inlet of the synthesis reactor.

[0024] Preferably, the water replenishment system comprises a raw water tank, a booster pump, a fully automatic water softener, a soft water tank and a second water replenishment pump which are connected in sequence.

[0025] Preferably, the water replenishment system is connected to the electric heating steam generator and the gas phase inlet of the synthesis reactor in sequence.

[0026] Preferably, the energy release module also includes a gas cylinder. After the cooling water pipeline is connected to the synthesis reactor, it is also connected to the inlet end of the gas cylinder. The outlet end of the gas cylinder is connected to the synthesis reactor, so as to use the water vapor after heat exchange in the synthesis reaction process as a supplementary raw material for the synthesis reaction.

[0027] Preferably, a steam ejector is provided at the outlet end of the gas sub-cylinder.

[0028] In the present invention, the energy release module can be connected to the steam user at the rear end through the gas distribution cylinder.

[0029] In the present invention, the second solid-liquid heat exchanger may be a built-in or external partition wall heat exchanger.

[0030] In the present invention, the second hydroxide material bin is connected in series with the first hydroxide material bin.

[0031] In the present invention, the first hydroxide material bin and the second hydroxide material bin are the same hydroxide material bin.

[0032] In the present invention, the second hydroxide storage bin is directly connected to the decomposition reactor.

[0033] In the present invention, the energy storage module and the energy release module can be arranged in the same area, or can be arranged in two different areas respectively; when the energy storage module and the energy release module are respectively arranged in two areas far away from each other, the hydroxide from the silo of the energy release module can be transported and supplied to the energy storage module, and the oxide from the energy storage module can be transported and supplied to the energy release module, as raw materials for energy storage and energy release, respectively.

[0034] The present invention also provides a thermochemical heat storage and release method, which uses the heat storage and release system as described above and includes the following stages:

[0035] Energy storage stage: the hydroxide in the decomposition reactor is heated to 510-610° C. to generate oxides and water vapor. After gas-solid separation in the first gas-solid separator, the oxides are heat exchanged and collected, and the water vapor is collected in the heat storage tank;

[0036] Energy release stage: adding oxides and water vapor to the synthesis reactor to generate hydroxides, exchanging heat and collecting the hydroxides after gas-solid separation in the second gas-solid separator, and refluxing the water vapor that does not participate in the reaction into the synthesis reactor;

[0037] When the hydroxide is calcium hydroxide, the oxide is calcium oxide;

[0038] When the hydroxide is magnesium hydroxide, the oxide is magnesium oxide;

[0039] When the hydroxide is ferrous hydroxide, the oxide is ferrous oxide.

[0040] In the present invention, by directly introducing high-temperature water vapor into the water body of the heat storage tank, heat and material energy can be stored at the same time, avoiding the use of additional indirect storage of the thermal energy of this high-temperature water vapor; it also solves the problem that the high-temperature water vapor generated in the energy storage stage is difficult to absorb.

[0041] In the present invention, preferably, in the energy storage stage, the pressure of the decomposition reactor is 0.08-0.3 MPaG.

[0042] Preferably, when the pressure of the decomposition reactor is normal pressure, the temperature of the decomposition reactor is 510°C.

[0043] Preferably, when the pressure of the decomposition reactor is 0.3 MPaG, the temperature of the decomposition reactor is 610°C.

[0044] In the present invention, as the pressure of the decomposition reactor increases, the decomposition reaction temperature will also increase. Liquid water is easy to be pressurized, but water vapor is difficult to be pressurized, and the pressurization cost is extremely high. The decomposition reactor has a certain pressure, and the water vapor generated during the decomposition reaction will also have a corresponding pressure and can be directly utilized.

[0045] In the present invention, preferably, in the energy storage stage, the temperature of the oxide entering the first solid-liquid heat exchanger is 610°C.

[0046] In the present invention, preferably, in the energy storage stage, the temperature of the oxide after the heat exchange is 25°C.

[0047] In the present invention, preferably, in the energy storage stage, the water temperature of the hot water storage tank is 98°C.

[0048] In the present invention, preferably, in the energy release stage, the temperature of the water vapor in the synthesis reactor is 180°C.

[0049] In the present invention, preferably, in the energy release stage, the temperature of the hydroxide generated in the synthesis reactor is 400-500°C.

[0050] In the present invention, preferably, in the energy release stage, the water vapor in the synthesis reactor includes water vapor from a water replenishment system of an electrically heated steam generator and / or reflux water vapor from a gas cylinder.

[0051] In the present invention, in the energy storage module, the energy stored in the water in the heat storage tank can be supplied to heat users below 100°C; in the energy release module, the heat of the synthesis reaction can be supplied to users below 400°C.

[0052] The present invention also provides an application of the thermochemical heat storage and release system as described above in the field of chemical energy storage and release.

[0053] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0054] The reagents and raw materials used in the present invention are commercially available.

[0055] The positive and progressive effects of the present invention are:

[0056] 1. The thermochemical heat storage and release system of the present application can store heat for a long time, avoiding the problem of high-temperature water vapor being difficult to absorb in the prior art. It can fully meet the cross-seasonal energy storage needs and can be used for thermal power peak regulation and other occasions. In addition, it can provide heat in different temperature ranges by collecting heat from the energy storage module and the energy release module.

[0057] 2. By designing the heat storage module in the system of the present application, the volume of water as the heat storage medium can be reduced. Compared with the prior art, the water consumption of the system of the present application can be reduced by 40%-60%, and high-quality heat can be generated.

[0058] 3. By adopting the heat storage and release system and method of the present application, only a part of the energy is lost through heat transfer, and more than 90% of the heat in the energy storage process can be stored or utilized.

[0059] 4. In the system of the present application, the energy storage module and the energy release module can realize the spatial coupling of the entire system through the distribution of hydroxides and oxides, better allocate resources, and avoid the influence of the positions of the energy storage module and the energy release module. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 This is a schematic structural diagram of the thermochemical heat storage and release system of Example 1 of the present invention.

[0061] Figure 2 This is a schematic diagram of the structure of the heat storage and release system of Comparative Example 1.

[0062] Description of reference numerals:

[0063] The first hydrogenation material warehouse 101

[0064] Decomposition reactor 102

[0065] The first gas-solid separator 103

[0066] Heating water tank 104

[0067] Hot water storage tank 105

[0068] The first solid-liquid heat exchanger 106

[0069] Oxide silo 107

[0070] Heater 108

[0071] Booster pump 109

[0072] Water tank 110

[0073] The first water supply pump 111

[0074] Drain port 112

[0075] Synthesis reactor 201

[0076] The second gas-solid separator 202

[0077] The second solid-liquid heat exchanger 203

[0078] The second hydrogenation material warehouse 204

[0079] Water replenishment system 205

[0080] Raw water tank 2051

[0081] Booster pump 2052

[0082] Fully automatic water softener 2053

[0083] Soft water tank 2054

[0084] Second water supply pump 2055

[0085] Electric heating steam generator 206

[0086] Cylinder 207

[0087] Steam User 208

[0088] Lithium bromide refrigerator 301

[0089] Heating system 302

[0090] Electric boiler 401

[0091] Hot water tank 402

[0092] Heat exchanger 403

[0093] Hot User 404. DETAILED DESCRIPTION

[0094] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0095] Example 1

[0096] Figure 1 Schematic diagram of the structure of the thermochemical heat storage and release system of this embodiment, the thermochemical heat storage and release system includes an energy storage module and an energy release module;

[0097] The energy storage module includes a first hydroxide material bin 101, a decomposition reactor 102, a first gas-solid separator 103, a first solid-liquid heat exchanger 106, an oxide material bin 107, a heating water tank 104, a hot water storage tank 105 and a water supply pipeline; the first hydroxide material bin 101 is connected to the decomposition reactor 102, the first hydroxide material bin 101 is used to provide calcium hydroxide, magnesium hydroxide or ferrous hydroxide, and the decomposition reactor 102 is used for the reaction of decomposing calcium hydroxide, magnesium hydroxide or ferrous hydroxide into oxides and water; the first gas-solid separator 103, a first solid-liquid heat exchanger 106, an oxide material bin 107, a heating water tank 104, a hot water storage tank 105 and a water supply pipeline; the first hydroxide material bin 101 is connected to the decomposition reactor 102, the first hydroxide material bin 101 is used to provide calcium hydroxide, magnesium hydroxide or ferrous hydroxide, and the decomposition reactor 102 is used for the reaction of decomposing calcium hydroxide, magnesium hydroxide or ferrous hydroxide into oxides and water; The feed port of the separator 103 and the solid phase outlet of the first gas-solid separator 103 are connected to the discharge port of the decomposition reactor 102 and the first solid-liquid heat exchanger 106 respectively. The gas phase outlet of the first gas-solid separator 103 is connected to the heating water tank 104 and the hot water storage tank 105 in sequence. The water supply pipeline is connected to the first solid-liquid heat exchanger 106 to achieve indirect heat exchange of the oxide. The discharge port of the first solid-liquid heat exchanger 106 is connected to the oxide silo 107; the oxide silo 107 is used to store calcium oxide, magnesium oxide or ferrous oxide.

[0098] The decomposition reactor 102 includes a heater 108 for providing heat for the decomposition reaction of the hydroxide; the heater 108 is connected to the power supply module;

[0099] A booster pump 109 is provided on the pipeline between the heating water tank 104 and the hot water storage tank 105; a steam ejector is provided inside the heating water tank 104 for introducing water vapor from the first gas-solid separator 103 into the heating water tank 104;

[0100] The water outlet of the first solid-liquid heat exchanger 106 is connected to the heating water tank 104 for supplying the outlet water in the first solid-liquid heat exchanger 106 to the heating water tank 104 .

[0101] The energy storage module further includes a water replenishment tank 110 and a first water replenishment pump 111 , and a water replenishment pipeline is connected to the first water replenishment pump 111 and the water replenishment tank 110 in sequence.

[0102] The hot water outlet of the heat storage tank 105 is connected in turn to the hot water output pipeline of the heat consumption module, and is connected to the water supply channel of the first solid-liquid heat exchanger 106 through the cooling water output pipeline of the heat consumption module, forming a hot water-cold water-hot water circulation loop; a drain port 112 is provided on the pipeline between the cooling water output pipeline of the heat consumption module and the water supply pipeline of the first solid-liquid heat exchanger 106; the heat consumption module includes a heating system 302 and a lithium bromide refrigerator 301;

[0103] The energy release module includes a synthesis reactor 201, a second gas-solid separator 202, a second solid-liquid heat exchanger, a second hydroxide bin 204 and a cooling water pipeline; the oxide bin 107 is connected to the solid phase feed port of the synthesis reactor 201, and the synthesis reactor 201 is also provided with a water inlet pipeline for providing the raw materials required for the synthesis reaction; the synthesis reactor 201 is used for the synthesis reaction of the oxide and water; the discharge port of the synthesis reactor 201 is connected to the feed port of the second gas-solid separator 202, and the water vapor outlet of the second gas-solid separator 202 is connected to the synthesis reactor 201 as a supplementary raw material for the synthesis reaction; the solid phase outlet of the second gas-solid separator 202 is connected to the second solid-liquid heat exchanger 203 and the second hydroxide bin 204 in sequence; the cooling water pipeline is connected to the second solid-liquid heat exchanger 203 and the synthesis reactor 201 in sequence to realize the heat exchange of the hydroxide and the synthesis reaction process respectively.

[0104] An electric heating steam generator 206 is provided on the water inlet pipe;

[0105] The energy release module also includes a water replenishment system 205, which is connected to the electric heating steam generator 206 and the gas phase inlet of the synthesis reactor 201 in sequence; the water replenishment system 205 includes a raw water tank 2051, a booster water pump 2052, a fully automatic water softener 2053, a soft water tank 2054 and a second water replenishment pump 2055 connected in sequence.

[0106] The energy release module further includes a gas cylinder 207, the inlet end of which is connected to a cooling water pipeline, and the outlet end of which is provided with a steam ejector; one outlet end of the gas cylinder 207 is connected to the synthesis reactor 201 as a supplementary raw material for the synthesis reaction; the energy release module is connected to a rear-end steam user 208 via the gas cylinder 207. The second hydroxide material bin 204 is used to store calcium hydroxide, magnesium hydroxide or ferrous hydroxide.

[0107] In the thermochemical heat storage and release system of this embodiment, the energy storage module is arranged in a place close to the electric energy and with a large space; the thermochemical energy release module is arranged in a place close to the heat user, such as in an industrial park. In addition, this embodiment can store heat for a long time and can fully meet the cross-seasonal energy storage needs; and it can reduce the volume of water as the heat storage medium and can generate high-quality heat.

[0108] Example 2

[0109] This embodiment is a thermochemical heat storage and release method, and adopts the thermochemical heat storage and release system of embodiment 1, which includes the following stages:

[0110] Energy storage stage: the calcium hydroxide in the decomposition reactor 102 is heated to 510-610° C. to generate calcium oxide and water vapor. After gas-solid separation in the first gas-solid separator 103, the calcium oxide is heat exchanged and collected, and the water vapor is collected in the heat storage tank 105;

[0111] Energy release stage: calcium oxide and water vapor are added to the synthesis reactor 201 to generate calcium hydroxide. After gas-solid separation in the second gas-solid separator, the calcium hydroxide is heat exchanged and collected, and the water vapor that does not participate in the reaction is refluxed to the synthesis reactor 201.

[0112] In the energy storage stage, the pressure of the decomposition reactor 102 is 0.3 MPaG, and the temperature of the decomposition reactor is 610°C; the temperature of the calcium oxide entering the first solid-liquid heat exchanger 106 is 610°C; the temperature of the calcium oxide after heat exchange is 25°C; and the water temperature of the hot water storage tank 105 is 98°C.

[0113] In the energy release stage, the temperature of the calcium hydroxide generated in the synthesis reactor 201 is 400-500° C.; the water vapor in the synthesis reactor 201 includes the water vapor of the water replenishment system 205 of the electrically heated steam generator 206 and / or the reflux water vapor of the gas cylinder 207.

[0114] Effect Example 1

[0115] System thermal efficiency and heat storage efficiency

[0116] System thermal efficiency refers to the effective utilization rate of the thermal energy of the entire system, that is, system thermal efficiency = system output heat / system input heat × 100%;

[0117] The heat storage efficiency refers to the ratio of the heat stored in the system to the heat input of the entire system, that is, heat storage efficiency = system stored heat / system input heat*100%.

[0118] Taking the ambient temperature of 20℃ as the benchmark, at 0.3MPaG, calcium hydroxide is heated to 610℃ for decomposition reaction, decomposing into 610℃ calcium oxide and 610℃ water vapor; without considering the heat dissipation loss of the system, the heat absorbed by the system can be divided into three parts: the heat stored in high-temperature calcium oxide (mainly sensible heat), the heat stored in high-temperature water vapor (mainly latent heat of gasification phase change), and the stored chemical energy (heat absorbed by the breaking of chemical bonds during the decomposition of calcium hydroxide). These three parts of heat account for approximately 20%, 41%, and 39% of the total heat absorbed by the system; among them, the heat stored in calcium oxide (20%) and chemical energy (39%) can be stored for a long time, while the heat contained in high-temperature water vapor is difficult to store directly, and can only be considered for indirect storage or timely absorption.

[0119] Assuming that under ideal conditions, when calcium hydroxide is decomposed by electric heating, the 610°C high-temperature water vapor generated just meets the needs of a certain heat user and can be completely absorbed and utilized, then the thermal efficiency of this process is almost 100% (without considering heat dissipation losses), but the heat storage efficiency is only 59% (percentage of heat stored in high-temperature calcium oxide + percentage of chemical energy). If there is no suitable heat user at this time, and the generated water vapor is not absorbed by the heat user or can only be partially absorbed, then the system thermal efficiency will drop to as low as 59%, while the heat storage efficiency will not be affected.

[0120] Since the system of Example 1 can fully store three parts of heat (calcium oxide heat, water vapor heat, and chemical energy), it solves the problem that the high-temperature water vapor generated during the decomposition of calcium hydroxide cannot be consumed in time, and uses high-temperature water vapor mixed with make-up water to form water body heat storage, and indirectly stores the heat of this part of water vapor. This can not only improve the heat storage efficiency of the entire system, but also avoid reducing the thermal efficiency.

[0121] The thermal efficiency and heat storage efficiency of the system of Example 1 can both reach over 90%.

[0122] Comparative Example 1

[0123] Figure 2 Schematic diagram of the structure of the heat storage and release system of this comparative example, which belongs to an existing pure water body heat storage system, which includes an electric boiler 401, a hot water storage tank 402 and a heat exchanger 403; the electric boiler 401 and the hot water storage tank 402 form a heat storage circuit, the electric boiler 401 and the heat exchanger 403 form a first heat release circuit, the hot water storage tank 402 and the heat exchanger 403 form a second heat release circuit, and the heat exchanger 403 is connected to a heat user 404.

[0124] The heat storage and release system uses wind and solar power abandonment or grid off-peak power to directly drive the electric boiler 401 to heat hot water, and then stores the hot water in the hot water storage tank 402 (due to the large volume of water, cross-seasonal heat storage often uses natural caves, artificial reservoirs, etc. as hot water carriers) to store heat; when heat release is required, the heat of the stored hot water is transferred to the heat user 404 through the heat exchanger 403. The high-temperature side of the heat exchanger obtains 30-50℃ primary return water after heat exchange at 95℃ primary supply water, and the low-temperature side of the heat exchanger obtains 40℃ return water after heat exchange at 60℃ supply water.

[0125] For this comparative example, if 1.32 tons of calcium hydroxide (610°C) is decomposed by heat, 1 ton of calcium oxide (610°C) and 320 kg of water vapor (610°C) will be produced. In this process, the system absorbs heat, that is, stores about 1.7 GJ of heat. Among them, the 1 ton of calcium oxide (610°C) produced can be stored for a long time; but the 320 kg of water vapor (610°C) produced is difficult to store because of its large volume or high pressure.

[0126] If the water vapor is to be converted into liquid for storage, that is, to perform adiabatic compression, the water vapor will exceed its critical pressure; moreover, the temperature of the water vapor will rise during the compression process, and the compression work will consume additional high-grade energy. Even so, it cannot be compressed directly into liquid, and heat needs to be released to the outside.

[0127] If the water vapor is to be converted into liquid for storage, that is, to perform adiabatic compression, the water vapor will exceed its critical pressure; moreover, the temperature of the water vapor will rise during the compression process, and the compression work will consume additional high-grade energy. Even so, it cannot be compressed directly into liquid, and heat needs to be released to the outside.

[0128] When 610℃ steam is generated, if there is no heat user needing it, this heat will be lost.

[0129] Effect Example 2

[0130] In addition, compared with the system of Example 1 and the system of Comparative Example 1, the volume of the hot water storage body is reduced by nearly 40%-60%.

[0131] In the normal temperature heat storage stage of CaO powder, the volume of water in the composite heat storage of calcium-based and water in the present application is reduced by 40% compared with the single water heat storage; in the heat release stage of high temperature storage of 510-610℃, the volume of water in the composite heat storage of calcium-based and water in the present application is reduced by 60% compared with the single water heat storage. This is very effective in large-scale heat storage.

[0132] Different options are available depending on the heat user group. For example, if the storage duration is within 8 to 10 hours, high-temperature storage of CaO can be selected; if the storage duration is calculated on a monthly basis and cross-seasonal storage, room-temperature storage can be considered.

[0133] Now take 12MW / 12MWh heat storage as an example:

[0134] For the system in Example 1, the volume of hot water storage required is about 133m 3 (Water temperature rises from 20℃ to 98℃), and only 98℃ hot water can be provided during energy release.

[0135] The system of Example 1 only needs 81m of hot water storage 3 (CaO / Ca(OH)2 is stored at room temperature. If CaO / Ca(OH)2 is stored at high temperature, the volume of the hot water storage body can be further reduced to 54m 3 ), calcium oxide 2.4m 3 .

[0136] This is only the data of heat storage power of 12MW and heat storage for 1 hour. If cross-season energy storage is considered, 8 hours of heat storage per day is calculated for 5 months a year (4 months of heating season and 3 months of cooling season are deducted from the whole year). If the traditional heat storage technology is used, the volume of the hot water body required is 159600m 3 After adopting the solution of this application, the hot water storage volume can be reduced to 63840m 3 , which is very significant in reducing space occupation and investment costs.

Claims

1. A thermochemical heat storage and release system, characterized in that: It includes an energy storage module and an energy release module; The energy storage module includes a first hydroxide silo, a decomposition reactor, a first gas-solid separator, a first solid-liquid heat exchanger, an oxide silo, a heating water tank, a hot water storage tank and a water supply pipeline; the first hydroxide silo is connected to the decomposition reactor, the first hydroxide silo is used to provide calcium hydroxide, magnesium hydroxide or ferrous hydroxide, and the decomposition reactor is used for the reaction of calcium hydroxide, magnesium hydroxide or ferrous hydroxide decomposing into oxides and water; the feed port of the first gas-solid separator and the solid phase outlet of the first gas-solid separator are respectively connected to the discharge port of the decomposition reactor and the first solid-liquid heat exchanger, the gas phase outlet of the first gas-solid separator is connected to the heating water tank and the hot water storage tank in turn, the water supply pipeline is connected to the first solid-liquid heat exchanger to realize indirect heat exchange of oxides, and the discharge port of the first solid-liquid heat exchanger is connected to the oxide silo; the oxide silo is used to store calcium oxide, magnesium oxide or ferrous oxide; The energy release module includes a synthesis reactor, a second gas-solid separator, a second solid-liquid heat exchanger, a second hydroxide bin and a cooling water pipeline; the oxide bin is connected to the solid phase feed port of the synthesis reactor; the synthesis reactor is also provided with a water inlet pipeline for providing the raw materials required for the synthesis reaction; the synthesis reactor is used for the synthesis reaction of the oxide from the oxide bin and water; the discharge port of the synthesis reactor is connected to the feed port of the second gas-solid separator, and the water vapor outlet of the second gas-solid separator is connected to the synthesis reactor as a supplementary raw material for the synthesis reaction; the solid phase outlet of the second gas-solid separator is connected to the second solid-liquid heat exchanger and the second hydroxide bin in sequence; the cooling water pipeline is connected to the second solid-liquid heat exchanger and the synthesis reactor in sequence to realize heat exchange of hydroxide and synthesis reaction process respectively.

2. The thermochemical heat storage and release system according to claim 1, characterized in that: In the energy storage module, the decomposition reactor includes a heater for providing heat for the decomposition reaction of calcium hydroxide, magnesium hydroxide or ferrous hydroxide; And / or, a booster pump is provided on the pipeline between the heating water tank and the hot water storage tank; And / or, a steam injector is provided at the feed inlet of the heating water tank for introducing water vapor from the first gas-solid separator into the heating water tank; And / or, the water outlet of the first solid-liquid heat exchanger is connected to the heating water tank, so as to supply the outlet water in the first solid-liquid heat exchanger to the heating water tank.

3. The thermochemical heat storage and release system according to claim 1, characterized in that: The energy storage module further includes a water replenishment tank and a first water replenishment pump. Before the water replenishment pipeline is connected to the first solid-liquid heat exchanger, it is also connected to the water replenishment tank through the first water replenishment pump.

4. The thermochemical heat storage and release system according to claim 1, characterized in that: In the energy storage module, the hot water outlet of the heat storage tank is used to connect to the hot water input pipeline of the heat consumption module, and is connected to the water supply pipeline of the first solid-liquid heat exchanger through the cooling water output pipeline of the heat consumption module to form a hot water-cold water-hot water circulation loop; Preferably, a drain port is provided on the pipeline between the heat exchange pipeline of the heat consumption module and the water vapor channel of the first solid-liquid heat exchanger.

5. The thermochemical heat storage and release system according to claim 1, characterized in that: In the energy release module, an electric heating steam generator is provided on the water inlet pipe; And / or, the energy release module further comprises a water replenishment system, which is connected to the gas phase inlet of the synthesis reactor; wherein, preferably, the water replenishment system comprises a raw water tank, a booster water pump, a fully automatic water softener, a soft water tank and a second water replenishment pump which are connected in sequence; Preferably, the water replenishment system is connected to the electric heating steam generator and the gas phase inlet of the synthesis reactor in sequence.

6. The thermochemical heat storage and release system according to claim 1, characterized in that: The energy release module further includes a gas cylinder. After the cooling water pipeline is connected to the synthesis reactor, it is also connected to the inlet end of the gas cylinder. The outlet end of the gas cylinder is connected to the synthesis reactor, and is used to use the water vapor after heat exchange in the synthesis reaction process as a supplementary raw material for the synthesis reaction. Preferably, a steam ejector is provided at the outlet end of the gas sub-cylinder.

7. The thermochemical heat storage and release system according to claim 1, characterized in that: The second hydroxide material bin is connected in series with the first hydroxide material bin; Or, the first hydrogen oxidizing material warehouse and the second hydrogen oxidizing material warehouse are the same hydrogen oxidizing material warehouse; Alternatively, the second hydroxide storage bin is directly connected to the decomposition reactor.

8. A thermochemical heat storage and release method, characterized in that: It adopts the thermochemical heat storage and release system as described in any one of claims 1 to 7, which includes the following stages: Energy storage stage: the hydroxide in the decomposition reactor is heated to 510-610° C. to generate oxides and water vapor. After gas-solid separation in the first gas-solid separator, the oxides are heat exchanged and collected, and the water vapor is collected in the heat storage tank; Energy release stage: adding oxides and water vapor to the synthesis reactor to generate hydroxides, exchanging heat and collecting the hydroxides after gas-solid separation in the second gas-solid separator, and refluxing the water vapor that does not participate in the reaction into the synthesis reactor; When the hydroxide is calcium hydroxide, the oxide is calcium oxide; When the hydroxide is magnesium hydroxide, the oxide is magnesium oxide; When the hydroxide is ferrous hydroxide, the oxide is ferrous oxide.

9. The heat storage and release method according to claim 8, characterized in that: In the energy storage stage, the pressure of the decomposition reactor is 0.08-0.3 MPaG; and / or, in the energy storage stage, the temperature of the oxide entering the first solid-liquid heat exchanger is 610° C.; and / or, in the energy storage stage, the temperature of the oxide after the heat exchange is 25° C.; and / or, in the energy storage stage, the water temperature of the hot water storage tank is 98° C.; and / or, in the energy release stage, the temperature of the hydroxide generated in the synthesis reactor is 400-500° C.; And / or, in the energy release stage, the water vapor in the synthesis reactor includes water vapor from a water replenishment system of an electrically heated steam generator and / or reflux water vapor from a gas cylinder.

10. Application of the thermochemical heat storage and release system according to any one of claims 1 to 7 in the field of chemical energy storage and release.

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