Multi-steam-source cooling system of thermochemical energy storage device and control method of multi-steam-source cooling system

Abstract

The invention relates to the technical field of thermochemical energy storage, in particular to a multi-steam-source cooling system of a thermochemical energy storage device, which comprises a cooling steam supply unit comprising at least three mutually independent and switchable steam sources; the cooling execution unit comprises a cooling header communicated with each steam source and a cooling spray pipe of which one end is connected to the cooling header and the other end extends into the reactor; and the measurement and control unit comprises a header sensor used for monitoring the steam state in the cooling header. By arranging three cooling steam branches of the reactor shell side, the steam drum shell side and the independent accident electric heater, a multi-redundancy cooling supply system is constructed, the defects that the cooling capacity of a traditional single steam source fluctuates along with a main process, and the safety margin is insufficient during faults are overcome, meanwhile, the vertically-arranged porous atomizing spray pipes are adopted, and the cooling capacity of the single steam source is improved. And cooling steam can uniformly penetrate through the deep layer of the heat storage material in a planar form, so that local hot spots are effectively eliminated.

Description

Technical Field

[0001] This invention relates to the field of thermochemical energy storage technology, and in particular to a multi-vapor source cooling system for a thermochemical energy storage device and its control method. Background Technology

[0002] Thermochemical energy storage technology has received widespread attention in the fields of renewable energy consumption and industrial steam supply due to its advantages such as high energy density and long-term storage. During the energy storage stage, the electric heater in the reactor operates at high power continuously, generating a large amount of heat. In order to prevent the equipment from overheating and being damaged, an efficient and reliable cooling system must be provided.

[0003] Currently, such energy storage devices generally use steam from a single source for cooling, such as using only the steam generated by the reactor itself. This single steam source design has defects, such as the cooling capacity being heavily dependent on the operating status of the main process. When the main process fluctuates or fails, the cooling capacity is lost, resulting in low system safety redundancy. At the same time, a single pipeline makes it difficult to achieve precise and flexible control of steam flow and distribution, and cannot cope with complex operating conditions such as rapid changes in heating power or local overheating. In actual operation, especially in peak shaving scenarios that require rapid response, this defect has become one of the bottlenecks limiting the device's power increase and long-term safe operation. Summary of the Invention

[0004] In view of this, the purpose of this invention is to propose a multi-gas-source cooling system for thermochemical energy storage devices and its control method, so as to solve the technical problem of single gas source in existing thermochemical energy storage cooling systems.

[0005] To achieve the above objectives, the present invention provides a multi-vapor source cooling system for a thermochemical energy storage device, comprising: A cooling steam supply unit comprising at least three independent and switchable steam sources; The cooling execution unit includes a cooling manifold connected to each of the steam sources, and a cooling nozzle with one end connected to the cooling manifold and the other end extending into the reactor. The measurement and control unit includes a manifold sensor for monitoring the steam state inside the cooling manifold, a temperature sensor for monitoring the surface temperature of the energy storage heater inside the reactor, and a pressure sensor for monitoring the steam pressure inside the system. During operation, the cooling steam supply unit selectively activates different steam sources based on feedback from the measurement and control unit to provide cooling steam to the cooling execution unit.

[0006] As a preferred embodiment of the present invention, the steam source includes a reactor shell-side steam branch, a steam drum shell-side steam branch, and an emergency steam branch.

[0007] As a preferred embodiment of the present invention, the reactor shell-side steam branch is connected to the reactor shell-side outlet to directly obtain cooling steam I from the reactor shell side.

[0008] As a preferred embodiment of the present invention, the steam branch of the steam drum shell side is connected to the shell side of the steam drum to obtain cooling steam II from the steam drum.

[0009] As a preferred embodiment of the present invention, the emergency steam branch includes an emergency electric heater and a recovery water tank connected to the emergency electric heater to generate cooling steam III.

[0010] As a preferred embodiment of the present invention, the reactor shell-side steam branch, the steam drum shell-side steam branch, and the emergency steam branch are each equipped with a regulating valve and a check valve.

[0011] As a preferred embodiment of the present invention, the cooling nozzle is a porous atomizing nozzle that extends vertically into the heat storage material layer of the reactor.

[0012] As a preferred technical solution of the present invention, the porous atomizing nozzle has multiple sets of openings spaced apart along its axial direction on its pipe wall, and each set of openings includes multiple atomizing holes uniformly opened in the circumferential direction of the pipe wall.

[0013] To better address the aforementioned technical problems, the present invention also provides a multi-vapor source cooling control method based on any one of the above-described systems, the method comprising the following steps: S1. Real-time acquisition of reactor operating status parameters, including at least the surface temperature of the energy storage heater and the system steam pressure; S2. Based on the operating status parameters, determine the current cooling condition level; S3. Execute the corresponding cooling control strategy according to the cooling condition level: Strategy 1: When in the first-level operating condition, the steam branch of the reactor shell side is activated first, and its steam flow rate is dynamically adjusted according to the surface temperature of the energy storage heater. Strategy 2: When in the second stage of operation, the reactor shell-side steam branch will be gradually closed and switched to be mainly or completely supplied by the steam drum shell-side steam branch to enhance cooling and reduce system pressure. Strategy 3: When in the third-level emergency condition, activate the emergency steam branch for cooling.

[0014] As a preferred technical solution of the present invention, before activating any branch, a warm-up and saturation judgment step is also included. Based on the data of the manifold sensor, it is confirmed that the steam of the branch to be activated has reached the preset saturation state, and the warm-up of the drain pipe is completed.

[0015] The beneficial effects of this invention are: This invention constructs a multi-redundant cooling supply system by setting up three cooling steam branches: the reactor shell side, the steam drum shell side, and an independent emergency electric heater. This solves the defects of traditional single steam sources, such as the cooling capacity fluctuating with the main process and insufficient safety margin in case of failure. At the same time, the use of vertically arranged multi-hole atomizing nozzles enables the cooling steam to penetrate the deep layers of the heat storage material in a planar form, effectively eliminating local hot spots and avoiding material sintering and equipment overheating. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of the present invention.

[0018] The diagram is labeled as follows: A. Thermochemical reactor; B. Steam drum; C. Recovered water tank; 1. Energy storage heater; 2. Heat storage material layer; 3. Cooling nozzle; 4. Cooling manifold; 5. Drainage pipe; 6. Steam drum tube side; 7. Steam drum water level; 8. Steam drum shell side steam supply manifold; 9. Water pump; 10. Emergency electric heater; 11. Electric valve; 12. No. 1 regulating valve; 13. No. 2 regulating valve; 14. No. 3 regulating valve; 15. No. 1 check valve; 16. No. 2 check valve; 17. No. 3 check valve; 18. No. 4 regulating valve; 19. No. 5 regulating valve. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0020] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0021] like Figure 1 As shown, a multi-steam-source cooling system for a thermochemical energy storage device includes: a cooling steam supply unit comprising at least three independent and switchable steam sources; a cooling execution unit comprising a cooling manifold 4 connected to each steam source, and a cooling nozzle 3 connected at one end to the cooling manifold 4 and extending into the reactor A at the other end; and a measurement and control unit comprising a manifold sensor for monitoring the steam state within the cooling manifold 4, a temperature sensor for monitoring the surface temperature of the energy storage heater 1 within the reactor A, and a pressure sensor for monitoring the steam pressure within the system. During operation, the cooling steam supply unit selectively activates different steam sources based on feedback from the measurement and control unit to supply cooling steam to the cooling execution unit. The above technical solution solves the problems of insufficient regulation capacity and inability to cope with complex operating conditions in traditional single-steam-source cooling systems. Specifically, its core working principle is as follows: Multiple steam sources are provided through the cooling steam supply unit. The monitoring and control unit collects and analyzes parameters such as the surface temperature of the energy storage heater 1 and the system steam pressure in real time, and then controls the cooling steam supply unit to select or combine different steam sources. The cooling steam is then delivered to the cooling manifold 4 and cooling nozzle 3 of the cooling execution unit, and finally injected into the reactor A for cooling. During use, the system is powered on and initialized, and the monitoring and control unit continuously monitors it. When cooling is required, the control system automatically selects the steam branch and adjusts the valve opening according to preset logic, improving system safety, adaptability, and response speed. Parameters such as temperature, pressure, and saturation are monitored online throughout the process. The control method has clear levels and thresholds, and the logic is easy to implement. It can be directly ported to industrial DCS / PLC systems, providing an engineering-ready solution for thermochemical energy storage devices ranging from MW to hundreds of MW. The three branches each have their own independent pipes and valves (regulating valves 13, 12, 14 and check valves 15, 16, 17) connected to the cooling manifold 4. The opening, closing, or failure of any one branch does not physically affect the connectivity of the other branches. The activation of each branch is decided independently by the monitoring and control unit based on different judgment conditions. The second-level valves will not be activated under the first-level operating condition, and the third-level emergency can completely disregard the operation of the first two levels. When the reactor itself fails to produce steam, the first-level steam source fails, but the second-level steam source (steam stored in the steam drum, as mentioned later) and the third-level steam source (electrically heated steam, as mentioned later) can still independently provide the cooling medium.

[0022] In this embodiment, as Figure 1As shown, the system comprises three core containers: reactor A, steam drum B, and recovery water tank C. Reactor A is filled with heat storage material 2, which is enclosed by energy storage heater 1. The shell side of reactor A is connected to the tube side of steam drum B via pipe AB, and the outlet of the tube side of steam drum B is connected to recovery water tank C. The bottom outlet of recovery water tank C is connected to water pump 9, and the outlet of water pump 9 is connected to emergency electric heater 10. The working fluid at the outlet of emergency electric heater 10 is divided into two paths: one path returns to recovery water tank C via regulating valve 19, and the other path enters cooling manifold 4 via regulating valve 14 and check valve 17. The above technical solution can construct three independent and switchable steam sources. Specifically, its working principle is as follows: multiple steam sources are provided by the cooling steam supply unit. The measurement and control unit collects parameters such as the surface temperature t2 of the energy storage heater 1 and the system steam pressure (such as the steam drum pressure p2) in real time and makes analysis and decisions. Then, it controls the cooling steam supply unit to select or combine different steam sources and deliver the cooling steam to the cooling manifold 4 and cooling nozzle 3 of the cooling execution unit, and finally sprays it into the reactor A for cooling.

[0023] In this embodiment, the steam source includes a reactor shell-side steam branch, a steam drum shell-side steam branch, and an emergency steam branch. The above technical solution can solve the problem of cooling failure caused by the failure of a single steam source in traditional systems. Specifically, its working principle is as follows: it constructs three cooling resources with different characteristics that serve as backups for each other. During operation, the reactor shell-side steam branch is used first according to the operating conditions. In case of abnormality, it switches to the steam drum shell-side steam branch. In an emergency, the emergency steam branch is activated, thus constructing multi-level safety redundancy and improving system reliability.

[0024] In this embodiment, the reactor shell-side steam branch is connected to the shell-side outlet of reactor A to directly obtain cooling steam I from the shell side of reactor A; The above technical solution can solve the efficiency problem of using the system's own waste heat for instant cooling. Specifically, its working principle is as follows: the generated, high-temperature steam is directly extracted from the shell side of reactor A for its own cooling. After the cooling command is issued and the branch is selected, the corresponding regulating valve 13 is opened to allow the steam to flow into the cooling manifold 4 through the check valve 15. The response is fast and the energy is internally recycled.

[0025] In this embodiment, the steam branch of the steam drum shell side is connected to the shell side of the steam drum B to obtain cooling steam II from the steam drum B; The above technical solution can solve the problem of unstable parameters of the reactor's self-generated steam when the system pressure fluctuates or when a large flow of stable steam source is required. Its working principle is as follows: it utilizes the stable saturated steam stored in the pressure stabilizing unit, steam drum B. During operation, when the system needs this steam, the corresponding regulating valve 12 is opened, allowing the steam to enter the cooling manifold 4 through the check valve 16, providing a stable steam source to achieve system pressure "peak shaving" and deep cooling.

[0026] In this embodiment, the emergency steam branch includes an emergency electric heater 10 and a recovery water tank C connected to the emergency electric heater 10 to generate cooling steam III; The above technical solution can solve the extreme safety problem of losing all cooling capacity when the main system fails completely. Specifically, its working principle is as follows: Under the premise of being completely independent of the main process system, the water from the recovery water tank C is heated into saturated steam by the electric heater 10. In emergency conditions, the regulating valve 14 is opened to allow the steam to be injected into the cooling manifold 4 through the check valve 17, providing independent backup cooling, which is the last line of defense of the cooling system.

[0027] In this embodiment, the reactor shell-side steam branch, the steam drum shell-side steam branch, and the emergency steam branch are each equipped with a regulating valve and a check valve; The above technical solution can solve the problems of precise flow distribution and interlocking safety when multiple steam sources are coupled. Specifically, the reactor shell-side steam branch is equipped with a second regulating valve 13 and a first check valve 15; the steam drum shell-side steam branch is equipped with a first regulating valve 12 and a second check valve 16; and the emergency steam branch is equipped with a third regulating valve 14 and a third check valve 17. The regulating valves (12, 13, 14) are used to receive control signals and precisely regulate the steam flow of each branch or to execute switches; the check valves (15, 16, 17) are used to prevent steam backflow from interfering with other branches. During operation, the regulating valves (12, 13, 14) achieve automatic flow control and seamless switching between branches, realizing automated control and preventing accidents caused by reverse fluid flow.

[0028] In this embodiment, the cooling nozzle 3 is a porous atomizing nozzle that extends vertically into the heat storage material layer of reactor A; The above technical solution can solve the problems of small coverage and insufficient deep material cooling of traditional lateral or simple nozzle cooling. In a preferred embodiment, the energy storage heater 1 is arranged horizontally in reactor A, and multiple sets of cooling nozzles 3 are arranged vertically in a staggered manner. Their lower ends converge at the bottom of reactor A and connect to the cooling manifold 4. The working principle of the cooling nozzles 3 is as follows: after the cooling steam enters the nozzle 3 from the manifold 4, it is sprayed vertically into the depth of the material layer in the form of a fine jet through the atomization holes on it. During operation, it is only necessary to ensure that the steam is supplied normally to the manifold 4 to achieve uniform cross-section of reactor A and synchronous and efficient cooling of the material depth.

[0029] In this embodiment, the porous atomizing nozzle has multiple sets of openings spaced apart along its axial direction on its pipe wall, and each set of openings includes multiple atomizing holes uniformly opened in the circumferential direction of the pipe wall. The above technical solution can solve the problem of cooling dead zone and uneven distribution caused by a single air outlet or a single row of holes. Specifically, its working principle is as follows: steam is sprayed out from the layout of multiple axial groups and multiple circumferential holes in all directions to form a three-dimensional and uniform steam atomization coverage field, thereby improving cooling uniformity and efficiency.

[0030] This invention also provides a multi-vapor source cooling control method. Its working principle is based on intelligent decision-making according to state perception. A preferred workflow is detailed below with specific control parameters: S1. Real-time parameter acquisition: Real-time acquisition of operating status parameters of reactor A, including at least the surface temperature t2 of the energy storage heater 1 and the system steam pressure (in this embodiment, the shell-side pressure p2 of the steam drum B). Temperature measuring point t1 and pressure measuring point p1 for real-time monitoring of steam status are installed on the cooling manifold 4.

[0031] S2. Determine the operating condition level: Based on the operating status parameters, determine the current cooling operating condition level.

[0032] S3. Implement hierarchical control strategy: Strategy 1: Initial Operating Conditions of Energy Storage (Level 1): Energy storage heater 1 heats the thermal storage material 2 at no less than 95% of its rated power. When the bed temperature reaches the decomposition temperature and steam begins to be released, control valve 13 introduces cooling steam I at no less than 30% of its flow rate into the cooling manifold 4 through check valve 15. Simultaneously, interlocking electric valve 11 is opened to begin warming up the drain pipe 5. When the steam temperature t1 in the cooling manifold 4 is no lower than the saturation temperature corresponding to its pressure p1, the warming up is considered complete, and electric valve 11 is interlocked and closed. Subsequently, control valve 13 is gradually opened and put into automatic tracking mode, setting the temperature target δ (δ is the set value that makes the average surface temperature t2 of energy storage heater 1 lower than 50°C).

[0033] Strategy 2: Power-constrained condition (Level 2): ​​When the temperature difference between the thermal storage material 2 and the average surface temperature t2 of the energy storage heater 1 is less than 50°C, the system enters this condition. At this time, the large amount of steam generated in reactor A causes the pressure p2 of the steam drum B to rise. When p2 reaches the alarm value, the regulating valve 12 is opened. At the same time, the automatic mode of the regulating valve 13 is exited and gradually closed, and the regulating valve 12 is put into automatic mode, setting the pressure target Ф (Ф is the set value when the steam pressure p2 on the steam drum shell side is less than 0.1MPa).

[0034] Strategy 3: System Failure Condition (Level 3): This condition is entered when regulating valves 13 or 12 fail, or when both are fully open but the average surface temperature t2 of the energy storage heater 1 still cannot be suppressed from exceeding the limit. After confirming that regulating valve 14 is closed, regulate valve 19 is opened and emergency electric heater 10 is started. When the outlet steam temperature t3 of the electric heater reaches the saturation temperature corresponding to its outlet pressure p3, regulating valve 14 is opened and regulating valve 19 is gradually closed. Finally, regulating valve 14 is put into automatic mode, and the temperature target θ is set (θ is the set value that makes t2 lower than 50°C).

[0035] In this embodiment, before activating any branch, a warm-up and saturation determination step is also included. Based on the data from the manifold sensor, it is confirmed that the steam in the branch to be activated has reached a preset saturation state, and the warm-up of the drain pipe is completed. The above technical solution can solve the problems of water hammer, equipment damage, or the introduction of liquid water affecting cooling efficiency caused by the sudden introduction of high-temperature steam into cold pipelines. Specifically, its working principle is as follows: the state of steam in the newly introduced branch is monitored by the manifold sensors (temperature t1 and pressure p1 measuring points), the saturation temperature at the current pressure is calculated, and compared with the measured temperature. During operation, the regulating valve of the target branch is first slightly opened to warm up the pipeline, and the drain valve (electric valve 11 in this embodiment) is opened to drain the condensate; when t1 reaches or exceeds the saturation temperature corresponding to p1, the warm-up is determined to be complete, the drain valve is closed, and the branch is officially put into operation. This ensures a stable and safe start-up of the system and ensures that the cooling medium is dry saturated steam to optimize the cooling effect.

[0036] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

[0037] This invention aims to cover all such substitutions, modifications, and variations that fall within the scope of protection. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A multi-vapor source cooling system for a thermochemical energy storage device, characterized in that, include: A cooling steam supply unit comprising at least three independent and switchable steam sources; The cooling execution unit includes a cooling manifold (4) connected to each of the steam sources, and a cooling nozzle (3) with one end connected to the cooling manifold (4) and the other end extending into the reactor (A). The measurement and control unit includes a manifold sensor for monitoring the steam state inside the cooling manifold (4), a temperature sensor for monitoring the surface temperature of the energy storage heater (1) inside the reactor (A), and a pressure sensor for monitoring the steam pressure inside the system. During operation, the cooling steam supply unit selectively activates different steam sources based on the feedback from the measurement and control unit to provide cooling steam to the cooling execution unit.

2. The multi-vapor source cooling system for the thermochemical energy storage device according to claim 1, characterized in that, The steam source includes the reactor shell-side steam branch, the steam drum shell-side steam branch, and the emergency steam branch.

3. The multi-vapor source cooling system for the thermochemical energy storage device according to claim 2, characterized in that, The reactor shell-side steam branch is connected to the shell-side outlet of reactor (A) to directly obtain cooling steam I from the shell side of reactor (A).

4. The multi-vapor source cooling system for the thermochemical energy storage device according to claim 2, characterized in that, The steam branch of the steam drum shell side is connected to the shell side of the steam drum (B) to obtain cooling steam II from the steam drum (B).

5. The multi-vapor source cooling system for the thermochemical energy storage device according to claim 2, characterized in that, The emergency steam branch includes an emergency electric heater (10) and a recovery water tank (C) connected to the emergency electric heater (10) to generate cooling steam III.

6. The multi-vapor source cooling system for the thermochemical energy storage device according to claim 2, characterized in that, The reactor shell-side steam branch, the steam drum shell-side steam branch, and the emergency steam branch are each equipped with a regulating valve and a check valve.

7. The multi-vapor source cooling system for the thermochemical energy storage device according to claim 2, characterized in that, The cooling nozzle (3) is a porous atomizing nozzle that extends vertically into the heat storage material layer of the reactor (A).

8. The multi-vapor source cooling system for the thermochemical energy storage device according to claim 7, characterized in that, On the wall of the porous atomizing nozzle, multiple sets of openings are spaced apart along its axial direction, and each set of openings includes multiple atomizing holes evenly opened in the circumferential direction of the pipe wall.

9. A multi-vapor source cooling control method based on the system described in any one of claims 2-8, characterized in that, The method includes the following steps: S1. Real-time acquisition of operating status parameters of reactor (A), including at least the surface temperature of energy storage heater (1) and system steam pressure; S2. Based on the operating status parameters, determine the current cooling condition level; S3. Execute the corresponding cooling control strategy according to the cooling condition level: Strategy 1: When in the first stage of operation, the steam branch of the reactor shell side is activated first, and its steam flow rate is dynamically adjusted according to the surface temperature of the energy storage heater (1). Strategy 2: When in the second stage of operation, the reactor shell-side steam branch will be gradually closed and switched to be mainly or completely supplied by the steam drum shell-side steam branch to enhance cooling and reduce system pressure. Strategy 3: When in the third-level emergency condition, activate the emergency steam branch for cooling.

10. The multi-vapor source cooling control method according to claim 9, characterized in that, Before activating any branch, a warm-up and saturation determination step is also included. Based on the data from the manifold sensor, it is confirmed that the steam in the branch to be activated has reached the preset saturation state, and the condensate pipe warm-up is completed.

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