Multi-stage heating type ultra-high-temperature chemical heat pump system and control method thereof

Abstract

The invention provides a multi-stage heating type ultra-high-temperature chemical heat pump system and a control method thereof.The multi-stage heating type ultra-high-temperature chemical heat pump system comprises a high-temperature decomposition reaction bed, a low-temperature synthesis reaction bed, a heat regenerator, a high-temperature synthesis reaction bed, a low-temperature decomposition reaction bed and a molten salt mechanism, and the high-temperature decomposition reaction bed, the heat regenerator and the low-temperature synthesis reaction bed are sequentially communicated; the low-temperature decomposition reaction bed, the heat regenerator and the high-temperature synthesis reaction bed are communicated in sequence; fillers are arranged in the high-temperature decomposition reaction bed, the low-temperature synthesis reaction bed, the high-temperature synthesis reaction bed and the low-temperature decomposition reaction bed, and the high-temperature synthesis reaction bed and the low-temperature synthesis reaction bed are respectively connected with a heating device and are respectively communicated with the molten salt mechanism. Reaction heat is released for use in the reaction process of high-temperature synthesis and low-temperature synthesis, the heating effect with COP larger than 1 is obtained, and the method can be widely applied to the ultrahigh-temperature application fields such as industrial waste heat recovery and solar thermal power generation and has the dual value of industrial decarburization and energy gradient utilization.

Description

Technical Field

[0001] The present invention relates to the technical field of heat pumps, and in particular to a multi-stage heating type ultra-high temperature chemical heat pump system and a control method thereof. Background Art

[0002] According to the "World Energy Outlook 2024," demand for oil, natural gas, and coal will peak by 2030, necessitating accelerated growth in clean energy investment. To fulfill announced commitments and lead the world toward net-zero emissions, dependence on fossil fuels must be rapidly reduced after 2030. In this process, clean energy technologies such as heat pumps will be key to achieving an affordable and secure energy transition. Currently, thermochemical heat storage (TCES) is commonly used in ultra-high-temperature applications. While TCES storage can store thermal energy, it not only reduces energy quality during heat release but also reduces heat output. One solution to this problem is to incorporate thermochemical materials into a closed system to form a heat pump cycle, utilizing a low-temperature heat source to absorb heat and achieve an energy efficiency of greater than 1. A multi-stage heat-increasing ultra-high-temperature chemical heat pump primarily consists of a high-temperature reactor bed, a low-temperature reactor bed, and the connecting valves and piping. Compared to single-stage chemical heat pumps, there is no flowing liquid working fluid in the system, and the reaction temperature and heat output are both higher. The operation of a multi-stage heat pump system generally includes two processes: (1) the endothermic reaction process of the high-temperature bed, which uses an electric heater to heat the high-temperature reaction bed and uses molten salt to absorb the heat of the low-temperature reaction bed, so that the fluid in the high-temperature reaction bed decomposes and reacts and enters the low-temperature reaction bed for an exothermic reaction; (2) the endothermic reaction process of the low-temperature bed, which uses waste heat resources to heat the low-temperature reaction bed and uses molten salt to absorb the heat of the high-temperature reaction bed, so that the fluid in the low-temperature reaction bed enters the high-temperature reaction bed for an exothermic reaction. The endothermic processes of the high-temperature and low-temperature reaction beds can generate heat for use respectively, achieving a COP greater than 1. This system can be widely used in ultra-high-temperature applications such as industrial waste heat recovery and solar thermal power generation, and has the dual value of industrial decarbonization and energy cascade utilization.

[0003] Yawen Ren et al. (Performance evaluation of off-grid solar chemical heat pump for cooling / heating) analyzed the application prospects of a CaSO4-H2O chemical heat pump based on an off-grid combined heat and power system and a solar thermal system. S. Fujimoto et al. (CaO-Ca(OH)2 chemical heat pump system) established a Ca(OH)2-H2O-based chemical heat pump system that absorbs heat from a 400°C heat source and releases it at 80°C. While these studies demonstrated the feasibility of chemical heat pumps for medium- and low-temperature heat recovery, they failed to cover ultra-high temperature ranges.

[0004] Until now, the operating temperature range of existing chemical heat pump technology has generally been limited to medium and low temperature ranges. Applications in higher temperature ranges have primarily relied on mechanical heat pumps. While mechanical heat pumps offer high thermodynamic efficiency, they contain a large number of moving parts, resulting in complex system structures and high manufacturing and maintenance costs. On the other hand, while thermochemical heat storage technology has some applicability in high-temperature scenarios, it lacks the additional heat gain of heat pumps, weakening its competitiveness in the field of efficient thermal energy utilization.

[0005] Therefore, it is necessary to provide a multi-stage heat-increasing ultra-high temperature chemical heat pump system and its control method, which can operate efficiently in the ultra-high temperature range of 400℃ to 600℃, truly achieve an energy efficiency heat increase greater than 1, significantly improve the system's thermal energy utilization efficiency, and provide a more efficient, economical and reliable solution for ultra-high temperature scenarios such as industrial waste heat recovery and solar thermal power generation. Summary of the Invention

[0006] In view of the defects in the prior art, the object of the present invention is to provide a multi-stage heating type ultra-high temperature chemical heat pump system and a control method thereof.

[0007] According to the present invention, a multi-stage heat-increasing ultra-high temperature chemical heat pump system comprises: a high-temperature decomposition reaction bed, a low-temperature synthesis reaction bed, a regenerator, a high-temperature synthesis reaction bed, a low-temperature decomposition reaction bed, and a molten salt mechanism, wherein the high-temperature decomposition reaction bed, the regenerator, and the low-temperature synthesis reaction bed are sequentially connected; and the low-temperature decomposition reaction bed, the regenerator, and the high-temperature synthesis reaction bed are sequentially connected;

[0008] The high-temperature decomposition reaction bed, the low-temperature synthesis reaction bed, the high-temperature synthesis reaction bed and the low-temperature decomposition reaction bed are all provided with fillers. The high-temperature decomposition reaction bed, the low-temperature synthesis reaction bed, the high-temperature synthesis reaction bed and the low-temperature decomposition reaction bed are respectively connected to a heating device. The high-temperature decomposition reaction bed, the low-temperature synthesis reaction bed, the high-temperature synthesis reaction bed and the low-temperature decomposition reaction bed are respectively connected to a molten salt mechanism.

[0009] Preferably, the temperature of the low-temperature synthesis reaction bed is higher than that of the low-temperature decomposition reaction bed, the temperature of the high-temperature decomposition reaction bed is higher than that of the low-temperature synthesis reaction bed, the operating temperature of the high-temperature decomposition reaction bed is between 650°C and 800°C, the operating temperatures of the high-temperature synthesis reaction bed and the low-temperature synthesis reaction bed are between 400°C and 600°C, and the operating temperature of the low-temperature decomposition reaction bed is between 200°C and 400°C.

[0010] Preferably, the filler comprises metal hydroxides, metal carbonates, metal oxides, and metal hydrides having thermochemical heat storage and heat release capabilities.

[0011] Preferably, the high-temperature decomposition reaction bed is connected to the low-temperature synthesis reaction bed via a first ultra-high temperature valve, and the low-temperature decomposition reaction bed is connected to the high-temperature synthesis reaction bed via a second ultra-high temperature valve.

[0012] Preferably, the heating device includes: a first electric heater connected to the high-temperature decomposition reaction bed, a first heating device connected to the low-temperature synthesis reaction bed, a second electric heater connected to the high-temperature synthesis reaction bed, and a second heating device connected to the low-temperature decomposition reaction bed. The first electric heater and the second electric heater both use electric heating, and the first heating device and the second heating device both use waste heat heating.

[0013] Preferably, the molten salt mechanism comprises: a high-temperature synthesis bed side molten salt inlet, a high-temperature synthesis bed side molten salt outlet, a low-temperature synthesis bed side molten salt inlet and a low-temperature synthesis bed side molten salt outlet;

[0014] The high-temperature decomposition reaction bed and the high-temperature synthesis reaction bed are both connected to the molten salt inlet on the high-temperature synthesis bed side, and the high-temperature decomposition reaction bed and the high-temperature synthesis reaction bed are both connected to the molten salt outlet on the high-temperature synthesis bed side. The low-temperature synthesis reaction bed and the low-temperature decomposition reaction bed are both connected to the molten salt inlet on the low-temperature synthesis bed side, and the low-temperature synthesis reaction bed and the low-temperature decomposition reaction bed are both connected to the molten salt outlet on the low-temperature synthesis bed side.

[0015] Preferably, molten salt valves are provided between the inlets and outlets of the high-temperature decomposition reaction bed, the low-temperature synthesis reaction bed, the high-temperature synthesis reaction bed and the low-temperature decomposition reaction bed and the molten salt mechanism.

[0016] According to the present invention, a control method for a multi-stage heating-increasing ultra-high temperature chemical heat pump system includes a first heating-increasing mode and a second heating-increasing mode.

[0017] Preferably, the first heating mold comprises the following steps:

[0018] Step A1: turning on the first electric heater of the high-temperature decomposition reaction bed and the second heating device of the low-temperature decomposition reaction bed, opening the first ultra-high temperature valve between the high-temperature decomposition reaction bed and the low-temperature synthesis reaction bed, opening the second ultra-high temperature valves of the low-temperature decomposition reaction bed and the high-temperature synthesis reaction bed, opening the molten salt valve of the molten salt mechanism connected to the low-temperature synthesis reaction bed and the high-temperature synthesis reaction bed, and closing other molten salt valves;

[0019] Step A2: The high-temperature decomposition reaction bed generates a high-temperature decomposition vapor working medium by heating and decomposing, and the low-temperature decomposition reaction bed generates a low-temperature decomposition vapor working medium by heating and decomposing. The high-temperature decomposition vapor working medium and the low-temperature decomposition vapor working medium are respectively transferred to the low-temperature synthesis reaction bed and the high-temperature synthesis reaction bed through a regenerator;

[0020] Step A3, the low-temperature synthesis reaction bed exchanges heat with a molten salt mechanism, the molten salt mechanism stores reaction heat and reduces the temperature in the low-temperature synthesis reaction bed, thereby promoting the low-temperature synthesis reaction;

[0021] Step A4, the high-temperature synthesis reaction bed exchanges heat with the molten salt mechanism, the molten salt mechanism stores reaction heat and reduces the temperature in the high-temperature synthesis reaction bed, thereby promoting the high-temperature synthesis reaction;

[0022] Step A5: the first heating mode is stopped until the reactions in the four tanks reach equilibrium.

[0023] Preferably, the second heating mode includes the following steps:

[0024] Step B1: The first heating mode ends, the fillings in the four tanks react and change, causing the high and low temperature modes to switch, the first electric heater and the second heating device are turned off, the first heating device and the second electric heater are turned on, and the opened molten salt valve in the first heating mode is closed, and the closed molten salt valve is opened;

[0025] In step B2, high-temperature decomposition vapor and low-temperature decomposition vapor are generated by thermal decomposition, and synthesis reactions are respectively conducted to release heat, and then heat is exchanged with the molten salt mechanism. The molten salt mechanism stores the reaction heat and promotes the continuation of the synthesis reaction.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention connects a high-temperature decomposition reaction bed, a regenerator and a low-temperature synthesis reaction bed in sequence, and the low-temperature decomposition reaction bed, the regenerator and the high-temperature synthesis reaction bed are connected in sequence. Each reaction bed is connected to a molten salt mechanism. The switching of the first heating mode and the second heating mode is controlled by the molten salt valve control and the opening and closing of the heating device to achieve continuous operation of the heat pump system; by releasing the reaction heat for use in the reaction processes of high-temperature synthesis and low-temperature synthesis, a heating effect with a COP greater than 1 is obtained, which can be widely used in ultra-high-temperature application fields such as industrial waste heat recovery and solar thermal power generation, and has the dual value of industrial decarbonization and energy cascade utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0029] Figure 1 This is a schematic diagram of a multi-stage heating type ultra-high temperature chemical heat pump system mainly embodied in the present invention.

[0030] As shown in the figure:

[0031] DETAILED DESCRIPTION

[0032] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0033] Example 1

[0034] like Figure 1 As shown, a multi-stage heat-increasing ultra-high-temperature chemical heat pump system according to the present invention includes: a high-temperature decomposition reaction bed 1, a low-temperature synthesis reaction bed 2, a regenerator 3, a high-temperature synthesis reaction bed 4, a low-temperature decomposition reaction bed 5, and a molten salt mechanism. The high-temperature decomposition reaction bed 1, the regenerator 3, and the low-temperature synthesis reaction bed 2 are sequentially connected, and the low-temperature decomposition reaction bed 5, the regenerator 3, and the high-temperature synthesis reaction bed 4 are sequentially connected. Fillers are provided in the high-temperature decomposition reaction bed 1, the low-temperature synthesis reaction bed 2, the high-temperature synthesis reaction bed 4, and the low-temperature decomposition reaction bed 5. The high-temperature decomposition reaction bed 1, the low-temperature synthesis reaction bed 2, the high-temperature synthesis reaction bed 4, and the low-temperature decomposition reaction bed 5 are each connected to a heating device. The high-temperature decomposition reaction bed 1, the low-temperature synthesis reaction bed 2, the high-temperature synthesis reaction bed 4, and the low-temperature decomposition reaction bed 5 are each connected to the molten salt mechanism. The multi-stage thermochemical material heat-increasing ultra-high-temperature heat pump system is controlled by a molten salt valve and the heating device is turned on and off to achieve continuous operation of the heat pump system.

[0035] The temperature of the low-temperature synthesis reaction bed 2 is higher than that of the low-temperature decomposition reaction bed 5, and the temperature of the high-temperature decomposition reaction bed 1 is higher than that of the low-temperature synthesis reaction bed 2. The operating temperature of the high-temperature decomposition reaction bed 1 is between 650°C and 800°C, the operating temperature of the high-temperature synthesis reaction bed 4 and the low-temperature synthesis reaction bed 2 is between 400°C and 600°C, and the operating temperature of the low-temperature decomposition reaction bed 5 is between 200°C and 400°C.

[0036] The filler includes metal hydroxides, metal carbonates, metal oxides, and metal hydrides that have thermochemical heat storage and heat release capabilities. The filler component is preferably metal hydroxide because metal hydroxide has relatively good expansion heat conduction and mass transfer properties.

[0037] The pyrolysis reactor bed 1 is connected to the low-temperature synthesis reactor bed 2 via a first ultra-high temperature valve 6, while the low-temperature decomposition reactor bed 4 is connected to the high-temperature synthesis reactor bed 5 via a second ultra-high temperature valve 7. The first ultra-high temperature valve 6 controls the flow of gases between the pyrolysis reactor bed 1 and the low-temperature synthesis reactor bed 2; the first ultra-high temperature valve 7 controls the flow of gases between the pyrolysis reactor bed 4 and the low-temperature synthesis reactor bed 5. The ultra-high temperature valves are resistant to high temperatures and can operate stably at temperatures up to 800°C.

[0038] The heating device includes a first electric heater 20 connected to the high-temperature decomposition reaction bed 1, a first heating device 21 connected to the low-temperature synthesis reaction bed 2, a second electric heater 22 connected to the high-temperature synthesis reaction bed 4, and a second heating device 23 connected to the low-temperature decomposition reaction bed 5. The first electric heater 20 and the second electric heater 22 are both electrically heated, while the first heating device 21 and the second heating device 23 are both heated using medium- and low-temperature waste heat. In the first heating mode, the first electric heater 20 can heat the high-temperature decomposition reaction bed 1, and the second electric heater 22 can heat the low-temperature decomposition reaction bed 4. In the second heating mode, the first heating device 21 can heat the decomposition reaction, and the second heating device 23 can heat the decomposition reaction.

[0039] The molten salt mechanism includes a high-temperature synthesis bed-side molten salt inlet 16, a high-temperature synthesis bed-side molten salt outlet 17, a low-temperature synthesis bed-side molten salt inlet 18, and a low-temperature synthesis bed-side molten salt outlet 19. High-temperature decomposition reaction bed 1 and high-temperature synthesis reaction bed 4 are both connected to the high-temperature synthesis bed-side molten salt inlet 16, and are both connected to the high-temperature synthesis bed-side molten salt outlet 17. Low-temperature synthesis reaction bed 2 and low-temperature decomposition reaction bed 5 are both connected to the low-temperature synthesis bed-side molten salt inlet 18, and are both connected to the low-temperature synthesis bed-side molten salt outlet 19. High-temperature synthesis reaction bed 4 and high-temperature decomposition reaction bed 1 are connected in parallel to the molten salt outlet via a valve mechanism, while low-temperature synthesis reaction bed 2 and low-temperature decomposition reaction bed 5 are connected in parallel to the molten salt outlet via a valve mechanism. The flow direction of the molten salt outlet is controlled by a molten salt valve.

[0040] Molten salt valves are provided between the high-temperature decomposition reaction bed 1, the low-temperature synthesis reaction bed 2, the high-temperature synthesis reaction bed 4, and the low-temperature decomposition reaction bed 5 and the inlet and outlet of the molten salt mechanism. The molten salt valves control the flow direction of the molten salt outlet, including: a first molten salt valve 8, a second molten salt valve 9, a third molten salt valve 10, a fourth molten salt valve 11, a fifth molten salt valve 12, a sixth molten salt valve 13, a seventh molten salt valve 14, and an eighth molten salt valve 15. The high-temperature decomposition reaction bed 1 is connected to the third molten salt valve 10 and the fourth molten salt valve 11, the low-temperature synthesis reaction bed 2 is connected to the seventh molten salt valve 14 and the eighth molten salt valve 15, the high-temperature synthesis reaction bed 4 is connected to the first molten salt valve 8 and the second molten salt valve 9, and the low-temperature decomposition reaction bed 5 is connected to the fifth molten salt valve 12 and the sixth molten salt valve 13.

[0041] This application is preferably applied to industrial applications in various temperature zones. The multi-stage heat-increasing ultra-high temperature chemical heat pump system can release reaction heat from high-temperature and low-temperature synthesis reactions for use, achieving a COP greater than 1 to achieve a heat-increasing effect. This application can achieve efficient heating in a wide ultra-high temperature range and can be widely used in ultra-high temperature applications such as industrial waste heat recovery and solar thermal power generation, achieving the dual value of industrial decarbonization and energy cascade utilization.

[0042] Example 2

[0043] Based on Example 1, a control method for a multi-stage heating-increasing ultra-high temperature chemical heat pump system provided according to the present invention includes a first heating-increasing mode and a second heating-increasing mode.

[0044] The first heating mode comprises the following steps:

[0045] Step A1: Turn on the first electric heater 20 of the high-temperature decomposition reaction bed 1 and the second heating device 23 of the low-temperature decomposition reaction bed 5, open the first ultra-high temperature valve 6 between the high-temperature decomposition reaction bed 1 and the low-temperature synthesis reaction bed 2, open the second ultra-high temperature valve 7 between the low-temperature decomposition reaction bed 5 and the high-temperature synthesis reaction bed 4, open the molten salt valve of the molten salt mechanism connected to the low-temperature synthesis reaction bed 2 and the high-temperature synthesis reaction bed 4, and close the other molten salt valves;

[0046] Step A2: The high-temperature decomposition reaction bed 1 generates a high-temperature decomposition vapor working medium by heating and decomposing, and the low-temperature decomposition reaction bed 5 generates a low-temperature decomposition vapor working medium by heating and decomposing. The high-temperature decomposition vapor working medium and the low-temperature decomposition vapor working medium recover heat through the regenerator 3 and are transferred to the low-temperature synthesis reaction bed 2 and the high-temperature synthesis reaction bed 4 respectively;

[0047] Step A3: The low-temperature synthesis reaction bed 2 exchanges heat with the molten salt mechanism. The molten salt mechanism stores the reaction heat and reduces the temperature in the low-temperature synthesis reaction bed 2, thereby promoting the low-temperature synthesis reaction.

[0048] Step A4: The high-temperature synthesis reaction bed 4 exchanges heat with the molten salt mechanism. The molten salt mechanism stores the reaction heat and reduces the temperature in the high-temperature synthesis reaction bed 4, thereby promoting the high-temperature synthesis reaction.

[0049] Step A5: The first heating mode is continued until the reactions in the four tanks reach equilibrium.

[0050] The second heating mode includes the following steps:

[0051] Step B1: The first heating mode ends. The fillings in the four tanks undergo a reaction change, causing the high and low temperature modes to switch. The first electric heater 20 and the second heating device 23 are turned off, and the first heating device 21 and the second electric heater 22 are turned on. The opened molten salt valve in the first heating mode is closed, and the closed molten salt valve is opened.

[0052] In step B2, high-temperature decomposition vapor and low-temperature decomposition vapor are generated by thermal decomposition, and synthesis reactions are respectively conducted to release heat, and then heat is exchanged with the molten salt mechanism. The molten salt mechanism stores the reaction heat and promotes the continuation of the synthesis reaction.

[0053] This application is further illustrated by the following specific examples. The filler in the high-temperature decomposition reaction bed 1 is Ca(OH)2, the filler in the low-temperature synthesis reaction bed 2 is MgO, the filler in the high-temperature synthesis reaction bed 4 is CaO, and the filler in the low-temperature decomposition reaction bed 5 is Mg(OH)2. When the power plant has surplus power, the first electric heater 20 of the high-temperature decomposition reaction bed 1 is turned on and heated to 700°C, and the second heating device 23 of the low-temperature decomposition reaction bed 5 is turned on to 397°C. The molten salt valves in the low-temperature synthesis reaction bed 2 and the high-temperature synthesis reaction bed 4 are opened.

[0054] High-temperature decomposition reactor bed 1 undergoes a decomposition reaction under the action of a 700°C electric heater. The decomposed water vapor, after being reheated by regenerator 3, enters low-temperature synthesis reactor 2 to react with magnesium oxide, releasing reaction heat. The reaction temperature is approximately 550°C, and this reaction heat can be stored in the molten salt. Low-temperature decomposition reactor bed 5 undergoes a decomposition reaction at 397°C. The generated water vapor, after being reheated by regenerator 3, enters high-temperature synthesis reactor bed 4 to react with CaO, releasing reaction heat. The reaction temperature is approximately 550°C, and this reaction heat can be stored in the molten salt. During this process, the molten salt recovers approximately 550°C of heat from both low-temperature synthesis reactor bed 2 and high-temperature synthesis reactor bed 4, maintaining a COP above 1.5 and achieving the goal of heat increase.

[0055] The present application can efficiently recover the reaction heat from the high-temperature synthesis reaction and the low-temperature synthesis reaction in the first heating mode and the second heating mode, and obtain a heating effect with a COP greater than 1. It can be widely used in ultra-high temperature application fields such as industrial waste heat recovery and solar thermal power generation, and has the dual value of industrial decarbonization and energy cascade utilization.

[0056] In the description of this application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0057] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A multi-stage heating type ultra-high temperature chemical heat pump system, characterized in that: include: A high-temperature decomposition reaction bed (1), a low-temperature synthesis reaction bed (2), a regenerator (3), a high-temperature synthesis reaction bed (4), a low-temperature decomposition reaction bed (5), and a molten salt mechanism, wherein the high-temperature decomposition reaction bed (1), the regenerator (3), and the low-temperature synthesis reaction bed (2) are sequentially connected, and the low-temperature decomposition reaction bed (5), the regenerator (3), and the high-temperature synthesis reaction bed (4) are sequentially connected; The high-temperature decomposition reaction bed (1), the low-temperature synthesis reaction bed (2), the high-temperature synthesis reaction bed (4), and the low-temperature decomposition reaction bed (5) are all provided with fillers; the high-temperature decomposition reaction bed (1), the low-temperature synthesis reaction bed (2), the high-temperature synthesis reaction bed (4), and the low-temperature decomposition reaction bed (5) are respectively connected to a heating device; and the high-temperature decomposition reaction bed (1), the low-temperature synthesis reaction bed (2), the high-temperature synthesis reaction bed (4), and the low-temperature decomposition reaction bed (5) are respectively connected to a molten salt mechanism.

2. The multi-stage heating type ultra-high temperature chemical heat pump system according to claim 1, characterized in that: The temperature of the low-temperature synthesis reaction bed (2) is higher than that of the low-temperature decomposition reaction bed (5), the temperature of the high-temperature decomposition reaction bed (1) is higher than that of the low-temperature synthesis reaction bed (2), the operating temperature of the high-temperature decomposition reaction bed (1) is between 650°C and 800°C, the operating temperatures of the high-temperature synthesis reaction bed (4) and the low-temperature synthesis reaction bed (2) are between 400°C and 600°C, and the operating temperature of the low-temperature decomposition reaction bed (5) is between 200°C and 400°C.

3. The multi-stage heating type ultra-high temperature chemical heat pump system according to claim 1, characterized in that: The filler includes metal hydroxides, metal carbonates, metal oxides, and metal hydrides having thermochemical heat storage and heat release capabilities.

4. The multi-stage heating type ultra-high temperature chemical heat pump system according to claim 1, characterized in that: The high-temperature decomposition reaction bed (1) is connected to the low-temperature synthesis reaction bed (2) via a first ultra-high temperature valve (6), and the low-temperature decomposition reaction bed (4) is connected to the high-temperature synthesis reaction bed (5) via a second ultra-high temperature valve (7).

5. The multi-stage heating type ultra-high temperature chemical heat pump system according to claim 1, characterized in that: The heating device comprises: a first electric heater (20) connected to a high-temperature decomposition reaction bed (1), a first heating device (21) connected to a low-temperature synthesis reaction bed (2), a second electric heater (22) connected to a high-temperature synthesis reaction bed (4), and a second heating device (23) connected to a low-temperature decomposition reaction bed (5); the first electric heater (20) and the second electric heater (22) are both electrically heated, and the first heating device (21) and the second heating device (23) are both heated by waste heat.

6. The multi-stage heating type ultra-high temperature chemical heat pump system according to claim 1, characterized in that: The molten salt mechanism comprises: a high-temperature synthesis bed side molten salt inlet (16), a high-temperature synthesis bed side molten salt outlet (17), a low-temperature synthesis bed side molten salt inlet (18), and a low-temperature synthesis bed side molten salt outlet (19); The high-temperature decomposition reaction bed (1) and the high-temperature synthesis reaction bed (4) are both in communication with the high-temperature synthesis bed side molten salt inlet (16), the high-temperature decomposition reaction bed (1) and the high-temperature synthesis reaction bed (4) are both in communication with the high-temperature synthesis bed side molten salt outlet (17), the low-temperature synthesis reaction bed (2) and the low-temperature decomposition reaction bed (5) are both in communication with the low-temperature synthesis bed side molten salt inlet (18), and the low-temperature synthesis reaction bed (2) and the low-temperature decomposition reaction bed (5) are both in communication with the low-temperature synthesis bed side molten salt outlet (19).

7. The multi-stage heating type ultra-high temperature chemical heat pump system according to claim 1, characterized in that: Molten salt valves are provided between the high-temperature decomposition reaction bed (1), the low-temperature synthesis reaction bed (2), the high-temperature synthesis reaction bed (4), and the low-temperature decomposition reaction bed (5) and the inlets and outlets of the molten salt mechanism.

8. A control method for a multi-stage heating type ultra-high temperature chemical heat pump system according to any one of claims 1 to 7, characterized in that: It includes a first heating mode and a second heating mode.

9. The control method of the multi-stage heating type ultra-high temperature chemical heat pump system according to claim 8, characterized in that: The first heating mode comprises the following steps: Step A1, turning on the first electric heater (20) of the high-temperature decomposition reaction bed (1) and the second heating device (23) of the low-temperature decomposition reaction bed (5), opening the first ultra-high temperature valve (6) between the high-temperature decomposition reaction bed (1) and the low-temperature synthesis reaction bed (2), opening the second ultra-high temperature valve (7) between the low-temperature decomposition reaction bed (5) and the high-temperature synthesis reaction bed (4), opening the molten salt valve of the molten salt mechanism connected to the low-temperature synthesis reaction bed (2) and the high-temperature synthesis reaction bed (4), and closing the other molten salt valves; Step A2: The high-temperature decomposition reaction bed (1) generates a high-temperature decomposition vapor working medium by heating and decomposing, and the low-temperature decomposition reaction bed (5) generates a low-temperature decomposition vapor working medium by heating and decomposing. The high-temperature decomposition vapor working medium and the low-temperature decomposition vapor working medium are respectively transmitted to the low-temperature synthesis reaction bed (2) and the high-temperature synthesis reaction bed (4) through the regenerator (3); Step A3, the low-temperature synthesis reaction bed (2) exchanges heat with the molten salt mechanism, the molten salt mechanism stores reaction heat and reduces the temperature in the low-temperature synthesis reaction bed (2), thereby promoting the low-temperature synthesis reaction; Step A4, the high-temperature synthesis reaction bed (4) exchanges heat with the molten salt mechanism, the molten salt mechanism stores reaction heat and reduces the temperature in the high-temperature synthesis reaction bed (4), thereby promoting the high-temperature synthesis reaction; Step A5: the first heating mode is stopped until the reactions in the four tanks reach equilibrium.

10. The control method of the multi-stage heating type ultra-high temperature chemical heat pump system according to claim 9, characterized in that: The second heat increase mode comprises the following steps: Step B1, the first heating mode ends, the fillings in the four tanks undergo a reaction change, so that the high and low temperature modes are exchanged, the first electric heater (20) and the second heating device (23) are turned off, the first heating device (21) and the second electric heater (22) are turned on, the opened molten salt valve in the first heating mode is closed, and the closed molten salt valve is opened; In step B2, high-temperature decomposition vapor and low-temperature decomposition vapor are generated by thermal decomposition, and synthesis reactions are respectively conducted to release heat, and then heat is exchanged with the molten salt mechanism. The molten salt mechanism stores the reaction heat and promotes the continuation of the synthesis reaction.

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