Thermal chemical heat storage closed dehumidification drying device and method based on hydrated salt

Abstract

The invention discloses a closed dehumidification drying device and method based on thermal chemical heat storage of hydrated salt. The closed dehumidification drying device comprises a solar heat collection system, a drying chamber, a first chemical heat storage bed, a second chemical heat storage bed, a first reversing valve, a second reversing valve, a first fan and a second fan. The solar heat collection system is communicated with the first fan and the first reversing valve; the first reversing valve and the second reversing valve are respectively connected with the first chemical heat storage bed and the second chemical heat storage bed; the drying chamber is communicated with a second fan and a second reversing valve; hydrated salt is arranged in the first chemical heat storage bed and the second chemical heat storage bed. The closed drying and dehumidifying system is adopted, condensation and humidification water tanks are not needed, wet air generated by drying is directly used for hydrated salt heat release, the energy utilization efficiency is improved, and the production cost is reduced; the heat release process of the heat storage bed is coupled with the drying process, and the drying temperature is adjusted through heat release matching of multiple different types of salt in the heat storage bed.

Description

Technical Field

[0001] The invention relates to the field of solar energy heat collection, in particular to a closed dehumidification and drying device and method based on thermochemical heat storage of hydrated salt. Background Art

[0002] Solar drying is a drying technology that uses solar energy as a heat source. Solar energy is converted into heat energy through solar collectors, and then the heat is transferred to the material to be dried through hot air circulation or radiation, thereby achieving the purpose of reducing the moisture content of the material. This technology has the advantages of environmental protection, energy saving, and low cost. It is suitable for drying a variety of materials such as food, agricultural products, and wood. Since solar energy is a renewable energy source, this drying method has great potential for sustainable development.

[0003] Since solar energy is intermittent and unstable, in order to ensure continuous and efficient drying, the solar drying device is combined with the heat storage device. In the existing technology, most studies use water and low-melting-point phase change materials as heat storage media to form a system that integrates heat collection, heat storage and drying. However, it has the following disadvantages:

[0004] 1. Due to the low water content in the ambient air, the heat release rate is very slow, which is difficult to meet the drying requirements.

[0005] 2. The heat release and drying processes of the heat storage system work independently. The condensation heat of water vapor in the humid air generated by drying is released into the environment and is not effectively utilized. In addition, humidifying the ambient air will also cause the temperature of the air itself to drop.

[0006] 3. In the thermochemical heat storage drying system, in order to control the thermochemical reaction rate and adjust the temperature and humidity of the drying chamber, a condensation / humidification water tank is installed. The drying system is an open system, resulting in low utilization of thermal energy.

[0007] Therefore, there is an urgent need to provide a solution for a closed dehumidification and drying device based on thermochemical heat storage of hydrated salts. Summary of the invention

[0008] In order to solve the above problems, the technical solution of the present invention provides a closed dehumidification and drying device and method based on thermochemical heat storage of hydrated salts, which does not require condensation and humidification processes, and directly performs heat and humidity regulation through hydrated salts to improve the energy efficiency of thermal energy utilization.

[0009] According to a first aspect of the technical solution of the present invention, there is provided a closed dehumidification drying device based on thermochemical heat storage of hydrated salts, comprising: a solar thermal collection system, a drying chamber, a first chemical heat storage bed, a second chemical heat storage bed, a first reversing valve, a second reversing valve, a first fan and a second fan;

[0010] The solar thermal collection system is in communication with the first fan and the first reversing valve;

[0011] The first reversing valve and the second reversing valve are connected to the first chemical heat storage bed and the second chemical heat storage bed respectively;

[0012] The drying chamber is in communication with the second fan and the second reversing valve;

[0013] The first chemical heat storage bed and the second chemical heat storage bed contain hydrated salt.

[0014] In the above solution, the material absorption rate of the solar thermal collection system is greater than 0.8.

[0015] In the above solution, the first chemical heat storage bed and the second chemical heat storage bed respectively have a plurality of heat storage channels.

[0016] In the above solution, the heat storage channel is a porous structure.

[0017] In the above solution, the hydrated salt is located in the heat storage channel.

[0018] In the above solution, an airflow regulating device is provided on the heat storage channel.

[0019] According to a second aspect of the technical solution of the present invention, there is provided a heat storage drying method using a closed dehumidification drying device based on thermochemical heat storage of hydrated salts according to any one of the above-mentioned solutions, comprising:

[0020] S1, thermal energy storage: the solar thermal collection system absorbs sunlight, starts the first fan, and brings heat into the first chemical thermal storage bed through the hot air flow of the solar thermal collection system, the hydrated salt in the first chemical thermal storage bed is dehydrated, and the thermal energy is stored in the first chemical thermal storage bed;

[0021] S2, heat energy release: start the second fan to extract air from the drying chamber, the second chemical heat storage bed absorbs the steam in the air to form hydrated salt and releases heat at the same time, the air is heated and enters the drying chamber through the outlet of the second chemical heat storage bed for drying;

[0022] S3, switching between heat storage and heat release: when the heat of the first chemical heat storage bed and the second chemical heat storage bed is fully stored or exhausted, the first reversing valve and the second reversing valve are switched, the first chemical heat storage bed releases heat, and the second chemical heat storage bed stores heat.

[0023] In the above scheme, the hydrated salt is a hydrated salt composite material.

[0024] In the above scheme, the hydrated salt composite material includes one or more hydrated salts of MgSO4·7H2O, CaCl2·7H2O, K2CO3·1.5H2O and one or more of porous carbon, porous silicon carbide, porous diatomaceous earth, and foam metal to form a hydrated salt composite material.

[0025] In the above scheme, step S2 includes: the second chemical thermal storage bed has a plurality of thermal storage channels, and the dehumidification amount and the temperature rise amount of the airflow are adjusted by adjusting the airflow volume of each of the thermal storage channels.

[0026] Beneficial effects of the present invention:

[0027] The invention discloses a closed dehumidification and drying device and method based on thermochemical heat storage of hydrated salts. A closed drying and dehumidification system is adopted, and no condensation and humidification water tank is required. The wet air generated by drying is directly used for heat release of the hydrated salts, thereby improving energy utilization efficiency and reducing production costs. The heat storage bed heat release process is coupled with the drying process, and a plurality of heat storage channels are provided to place different types of hydrated salts for heat release, and the drying temperature can be adjusted. An airflow regulating device is provided on the heat storage channel, which cooperates with the hydrated salts in the heat storage channel, and adjusts the water absorption rate and heat release through the hydration reaction rates of different hydrated salts, so as to achieve heat and moisture balance with the drying process, thereby realizing a closed dehumidification and drying process of "heat collection-heat storage-drying". BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0029] Figure 1 This is a schematic structural diagram of a closed dehumidification and drying device based on thermochemical heat storage of hydrated salts provided by the present invention.

[0030] Among them, there are a solar energy heat collection system-1; a drying chamber-2; a first chemical heat storage bed-3; a second chemical heat storage bed-4; a first reversing valve-5; a second reversing valve-6; a first fan-7; and a second fan-8.

[0031] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0032] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0033] The terms "first", "second", etc. in the specification and claims of the present disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged where appropriate, so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein, for example.

[0034] In addition, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus that includes a series of steps or elements is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to such process, method, product, or apparatus.

[0035] Multiple includes two or more.

[0036] It should be understood that the term "and / or" used in this disclosure is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone.

[0037] like Figure 1 As shown, an embodiment of the technical solution of the present invention provides a closed dehumidification and drying device based on thermochemical heat storage of hydrated salts, including: a solar thermal collection system 1, a drying chamber 2, a first chemical heat storage bed 3, a second chemical heat storage bed 4, a first reversing valve 5, a second reversing valve 6, a first fan 7 and a second fan 8.

[0038] The solar thermal collection system 1 is connected to the first fan 7 and the first reversing valve 5; the first reversing valve 5 and the second reversing valve 6 are respectively connected to the first chemical heat storage bed 3 and the second chemical heat storage bed 4; the drying chamber 2 is connected to the second fan 8 and the second reversing valve 6; the first chemical heat storage bed 3 and the second chemical heat storage bed 4 contain hydrated salt.

[0039] The present invention adopts a closed drying and dehumidification system, which does not require a condensing and humidifying water tank. The wet air generated by drying is directly used to hydrate the salt to release heat, thereby improving energy utilization efficiency and reducing production costs. The heat release process of the heat storage bed is coupled with the drying process, and the drying temperature is adjusted by matching the heat release of different types of salt in the heat storage bed.

[0040] In this embodiment, the solar energy heat collection system 1 preferably uses a high-absorption material, wherein the material absorption rate is greater than 0.8. The use of a high-absorption material has a better heat absorption and collection effect, and improves the utilization rate of solar energy.

[0041] In this embodiment, the first chemical heat storage bed 3 and the second chemical heat storage bed 4 each have a plurality of heat storage channels. Specifically, the number of the heat storage channels is 2 to 10. Moreover, the heat storage channels are porous structures.

[0042] In this embodiment, the heat storage channel is preferably provided with an airflow regulating device for regulating the air flow of each heat storage channel. Specifically, the airflow regulating device is a louver blade or a valve, and the air flow of the heat storage channel is regulated by changing the opening of the louver blade or the valve.

[0043] The hydrated salt is located in the heat storage channel, and different hydrated salts can be placed in each heat storage channel. Since different hydrated salts have different hydration reaction rates and different exothermic temperatures, they can be independently adjusted through each heat storage channel to ultimately obtain dry airflows of different temperatures.

[0044] Furthermore, the airflow regulating device on the heat storage channel can be adjusted according to the heat release temperature of the hydrated salt in the heat storage channel. The water absorption rate and heat release amount can be adjusted by the hydration reaction rate of different hydrated salts to achieve thermal and moisture balance with the drying process, thereby realizing a closed dehumidification and drying process of "heat collection-heat storage-drying".

[0045] According to a second aspect of the technical solution of the present invention, there is provided a heat storage drying method using a closed dehumidification drying device based on thermochemical heat storage of hydrated salt as described above, comprising:

[0046] S1. Thermal energy storage: the solar thermal collection system 1 absorbs sunlight, starts the first fan 7, and brings heat into the first chemical thermal storage bed 3 through the hot air flow of the solar thermal collection system 1. The hydrated salt in the first chemical thermal storage bed 3 is dehydrated, and the thermal energy is stored in the first chemical thermal storage bed 3.

[0047] S2, heat energy release: start the second fan 8 to extract air from the drying chamber 2, the second chemical heat storage bed 4 absorbs the steam in the air to form hydrated salt, and releases heat at the same time, the air is heated and enters the drying chamber 2 through the outlet of the second chemical heat storage bed 4 for drying;

[0048] S3, switching between heat storage and heat release: when the heat of the first chemical heat storage bed 3 and the second chemical heat storage bed 4 is fully stored or exhausted, the first reversing valve 5 and the second reversing valve 6 are switched, the first chemical heat storage bed 3 releases heat, and the second chemical heat storage bed 4 stores heat.

[0049] The hydrated salt in steps S1 and S2 is a hydrated salt composite material. Specifically, the hydrated salt composite material includes one or more hydrated salts of MgSO4·7H2O, CaCl2·7H2O, K2CO3·1.5H2O and one or more of porous carbon, porous silicon carbide, porous diatomaceous earth, and foamed metal to form a hydrated salt composite material.

[0050] In steps S1 and S2, the first chemical heat storage bed 3 and the second chemical heat storage bed 4 are provided with a plurality of heat storage channels respectively.

[0051] In step S2, low-temperature humid air is extracted from the drying chamber 2, and the humid air passes through the second chemical heat storage bed 4; the wet steam in the humid air is absorbed by the salt, and high-temperature low-humidity air is obtained at the outlet of the second chemical heat storage bed 4, and the high-temperature low-humidity air enters the drying chamber 2 for drying.

[0052] Step S2 includes: adjusting the airflow dehumidification amount and temperature increase amount by adjusting the airflow volume of each heat storage channel on the second chemical heat storage bed 4.

[0053] The heat storage channel is provided with an airflow regulating device for regulating the air flow of each heat storage channel. Specifically, the airflow regulating device is a louver blade or a valve, and the air flow of the heat storage channel is regulated by changing the opening of the louver blade or the valve.

[0054] There are multiple hydrated salts in the heat storage channel. The types of hydrated salts in each heat storage channel are different. Since different hydrated salts have different hydration reaction rates and different exothermic temperatures, dry airflows with different temperatures can be obtained.

[0055] Furthermore, the ratio of dry airflows at different temperatures can be adjusted by adjusting the airflow adjustment devices of each heat storage channel.

[0056] According to actual use, steps S1 to S3 can be repeated to perform heat storage and heat release cycles in sequence.

[0057] Of course, in the present invention, the first chemical heat storage bed 3 and the second chemical heat storage bed 4 can store heat and release heat at the same time, as follows:

[0058] Thermal energy storage: the solar thermal collection system 1 absorbs sunlight, starts the first fan 7, and brings heat into the first chemical heat storage bed 3 through the hot air flow of the solar thermal collection system 1. The hydrated salt in the first chemical heat storage bed 3 is dehydrated, and the thermal energy is stored in the first chemical heat storage bed 3. After the first chemical heat storage bed 3 completes heat storage, the first reversing valve 5 and the second reversing valve 6 are switched, and the solar thermal collection system 1 continues to absorb sunlight, starts the first fan 7, and brings heat into the second chemical heat storage bed 4 through the hot air flow of the solar thermal collection system 1. The hydrated salt in the second chemical heat storage bed 4 is dehydrated, and the thermal energy is stored in the second chemical heat storage bed 4 until the heat storage is completed.

[0059] Heat energy release: Start the second fan 8 to extract low-temperature humid air from the drying chamber 2. The humid air passes through the second chemical heat storage bed 4. The second chemical heat storage bed 4 absorbs the steam in the air to form hydrated salts and releases heat at the same time. High-temperature and low-humidity air is obtained at the outlet of the second chemical heat storage bed 4. The high-temperature and low-humidity air enters the drying chamber 2 for drying. Then switch the first reversing valve 5 and the second reversing valve 6, and the second fan 8 continues to operate to extract low-temperature humid air from the drying chamber 2. The humid air passes through the first chemical heat storage bed 3. The first chemical heat storage bed 3 absorbs the steam in the air to form hydrated salts and releases heat at the same time. High-temperature and low-humidity air is obtained at the outlet of the first chemical heat storage bed 3. The high-temperature and low-humidity air enters the drying chamber 2 for drying.

[0060] Example

[0061] The closed dehumidification and drying device based on the thermochemical heat storage of hydrated salt provided in this embodiment has two hydrated salts, the first salt is CaCl6·6H2O, the charging temperature is 180°C, the exothermic temperature is 80°C, and the standard molar reaction enthalpy is 277kJ / mol; the second salt is Na2S·9H2O, the charging temperature is 80°C, the exothermic temperature is 35°C, and the standard molar reaction enthalpy is 148kJ / mol. The two hydrated salts are respectively located in two heat storage channels.

[0062] During drying, the wet air temperature is 50℃ and the relative humidity is 60%. If the airflow passes through the Na2S heat storage channel, the moisture in the air is absorbed by Na2S to form hydrated salt, and the temperature can rise to 60-70℃; if the airflow passes through the CaCl6 heat storage channel, it can rise to 80-90℃. Dry airflows of different temperatures can be obtained by adjusting the airflow ratio of the two channels according to the material requirements of the drying chamber.

[0063] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0064] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0065] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in each embodiment of the present invention.

[0066] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A closed dehumidification and drying device based on thermochemical heat storage of hydrated salts, characterized in that: include: A solar heat collection system, a drying chamber, a first chemical heat storage bed, a second chemical heat storage bed, a first reversing valve, a second reversing valve, a first fan and a second fan; The solar thermal collection system is in communication with the first fan and the first reversing valve; The first reversing valve and the second reversing valve are connected to the first chemical heat storage bed and the second chemical heat storage bed respectively; The drying chamber is in communication with the second fan and the second reversing valve; The first chemical heat storage bed and the second chemical heat storage bed contain hydrated salt.

2. The closed dehumidification and drying device based on thermochemical heat storage of hydrated salt according to claim 1, characterized in that: The material absorption rate of the solar thermal collection system is greater than 0.

8.

3. The closed dehumidification and drying device based on thermochemical heat storage of hydrated salt according to claim 1, characterized in that: The first chemical heat storage bed and the second chemical heat storage bed respectively have a plurality of heat storage channels.

4. The closed dehumidification and drying device based on thermochemical heat storage of hydrated salt according to claim 3, characterized in that: The heat storage channel is a porous structure.

5. The closed dehumidification and drying device based on thermochemical heat storage of hydrated salt according to claim 3, characterized in that: The hydrated salt is located in the thermal storage channel.

6. The closed dehumidification and drying device based on thermochemical heat storage of hydrated salt according to claim 3, characterized in that: An airflow regulating device is provided on the heat storage channel.

7. A heat storage drying method using the closed dehumidification drying device based on the thermochemical heat storage of hydrated salts according to any one of claims 1 to 6, characterized in that: include: S1, thermal energy storage: the solar thermal collection system absorbs sunlight, starts the first fan, and brings heat into the first chemical thermal storage bed through the hot air flow of the solar thermal collection system, the hydrated salt in the first chemical thermal storage bed is dehydrated, and the thermal energy is stored in the first chemical thermal storage bed; S2, heat energy release: start the second fan to extract air from the drying chamber, the second chemical heat storage bed absorbs the steam in the air to form hydrated salt and releases heat at the same time, the air is heated and enters the drying chamber through the outlet of the second chemical heat storage bed for drying; S3, switching between heat storage and heat release: when the heat of the first chemical heat storage bed and the second chemical heat storage bed is fully stored or exhausted, the first reversing valve and the second reversing valve are switched, the first chemical heat storage bed releases heat, and the second chemical heat storage bed stores heat.

8. The heat storage drying method of the closed dehumidification drying device based on the thermochemical heat storage of hydrated salt according to claim 7, characterized in that: The hydrated salt is a hydrated salt composite material.

9. The heat storage drying method of the closed dehumidification drying device based on the thermochemical heat storage of hydrated salt according to claim 8, characterized in that: The hydrated salt composite material comprises one or more hydrated salts of MgSO4·7H2O, CaCl2·7H2O, K2CO3·1.5H2O and one or more of porous carbon, porous silicon carbide, porous diatomaceous earth and foamed metal to form a hydrated salt composite material.

10. The heat storage drying method of the closed dehumidification drying device based on the thermochemical heat storage of hydrated salt according to claim 9, characterized in that: Step S2 includes: the second chemical thermal storage bed has a plurality of thermal storage channels, and the dehumidification amount and the temperature rise amount of the airflow are adjusted by adjusting the airflow volume of each of the thermal storage channels.

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