Phase change heat storage steam generation device and regulation method thereof

Abstract

The application discloses a phase change heat storage steam generating device and a regulation method thereof. The device comprises a heat preservation and heat storage tank body, a phase change heat storage material, vertically arranged segmented armored electric heaters, a heat exchange coil, a layered temperature sensing assembly, an independent power regulating assembly and a controller. Each armored electric heater is provided with at least two heating segments which can be independently started, stopped and regulated in power along the axial direction, and each heating segment corresponds to a corresponding vertical heat storage partition in the tank. The controller allocates power to the lower heating segments corresponding to the low-temperature solid phase area in priority according to the vertical temperature and solid-liquid state distribution formed after random heat release, and limits or closes the upper heating segments corresponding to the high-temperature liquid phase area. After the lower area reaches the melting completion condition and the temperature difference between the upper and lower areas is reduced, the upper heating segments are gradually put into use, and the temperature of each measuring point is lower than the upper limit of safety. The application can avoid the premature termination of heat storage of the whole machine due to the local over-temperature of the upper part, and improve the effective utilization rate of the phase change material and the available heat storage amount.

Description

Technical Field

[0001] This invention relates to the fields of phase change thermal energy storage, electric heating, and steam generation technology. Specifically, it relates to a thermal energy storage device that uses phase change materials to store electrical energy converted into heat and provides steam to the outside through coils. In particular, it relates to a device and its thermal energy storage control method that can independently adjust the power of different axial heating sections of a straight-tube armored electric heater according to the vertical temperature and solid-liquid state distribution inside the thermal energy storage tank. Background Technology

[0002] Utilizing off-peak electricity, renewable energy, or other fluctuating power sources for electric heating and heat storage, and releasing the heat as steam at the user end, is an important technological path to achieve industrial heating electrification and improve the capacity for renewable energy absorption. Phase change thermal energy storage materials have the characteristics of high latent heat of phase change, relatively stable storage temperature, and suitability for medium-temperature steam supply, and can be arranged in cuboid or other shaped insulated thermal energy storage tanks.

[0003] A typical electrically heated phase change thermal storage steam generator consists of multiple straight-tube armored electric heaters vertically inserted into a tank, with stainless steel heat exchange coils arranged between adjacent heaters. During heat storage, the electric heaters heat the surrounding phase change material uniformly along its length, causing it to heat up from a solid state and melt. During heat release, feedwater enters from the lower inlet of the coils, absorbs heat from the phase change material from bottom to top, and vaporizes it. Steam is output from the upper outlet on the same side.

[0004] The duration of steam use and steam load for industrial users are often random. When the heat release process ends before the phase change material has completely solidified, the lower part of the coil comes into contact with the low-temperature feedwater first and has a larger heat exchange driving force. The phase change material in the lower part of the tank usually cools down and solidifies first, while the upper part may still maintain a higher temperature and liquid state. This results in a non-uniform thermal state in the height direction of the tank, with "high-temperature liquid phase in the upper part and low-temperature solid phase or incomplete melting in the lower part".

[0005] When restarting thermal storage under these conditions, existing integrated straight-tube electric heaters typically output the same or a fixed proportion of heating power along their entire length. Due to their high initial temperature, the upper phase change material may approach its upper safe temperature limit within a short period. To prevent overheating and decomposition of the phase change material, existing control systems often reduce the power of the entire heater or stop heating altogether. At this time, the lower solid phase change material has not yet fully melted, resulting in actual usable heat storage lower than the design value, and potentially creating a large vertical temperature gradient and localized thermal stress.

[0006] While existing segmented electric heating elements can independently switch on and off different heating wires, relying solely on manual presets or fixed power ratios makes it difficult to automatically match the vertically non-uniform temperature and phase distribution resulting from random heat release. Furthermore, installing multiple short heating tubes at different heights within the tank increases the complexity of the tank's opening, sealing, and insulation structures. Therefore, it is necessary to propose a phase change thermal storage steam generator and its control method that combines a segmented straight-tube armored electric heater, stratified state sensing, and adaptive power allocation. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems of uneven vertical temperature and solid-liquid state in existing electrically heated phase change thermal storage steam generators after random heat release, and the tendency for the upper region to reach the upper limit of the safe temperature before the lower region melts insufficiently during reheating. This invention provides a segmented, independently electrically heated phase change thermal storage steam generator with vertically adaptable temperature stratification and its control method. This device can control the corresponding heating section according to the thermal state of each vertical thermal storage zone without increasing the number of heater installation openings at different heights of the tank. This allows for limited heating in high-temperature areas while low-temperature areas continue to receive heat, thereby improving the effective utilization of the phase change material and the available heat storage capacity of the device.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A phase change thermal storage steam generator and its control method include an insulated thermal storage tank, an integral phase change thermal storage material filled in the insulated thermal storage tank, multiple segmented armored electric heaters, heat exchange coils, layered temperature sensing components, a controller, and an independent power adjustment component; the integral phase change thermal storage material of this invention refers to the fact that the interior of the insulated thermal storage tank is a whole space, and all phase change thermal storage materials are filled in this space without physical structural partitions.

[0009] The segmented armored electric heater is a straight tube heater that is vertically inserted downward from the top of the insulated heat storage tank. It can be arranged in an array. Each segmented armored electric heater has at least two heating sections that are electrically isolated from each other and can be started, stopped and adjusted independently. Each heating section is connected to the independent power adjustment component through an independent power supply circuit so as to independently start, stop and adjust the output power.

[0010] The insulated thermal storage tank is defined along its height as at least two vertical thermal storage zones corresponding to the heating sections. In this invention, the vertical thermal storage zones are "defined" rather than divided by physical structure. Their number is the same as the number of heating sections of a single segmented armored electric heater. The heating sections of each segmented armored electric heater should generally have the same height design. Therefore, the entire insulated thermal storage tank can be defined as a corresponding number of vertical thermal storage zones. There is no physical isolation between the upper and lower zones; they are an integral structure.

[0011] The heat exchange coil assembly is arranged inside the tank, and the layered temperature sensing component is used to acquire the temperature information of each vertical heat storage zone. The layered temperature sensing component sets one or more temperature measuring points in each vertical heat storage zone.

[0012] The controller is connected to the layered temperature sensing component and the independent power adjustment component respectively. Based on the temperature of each measuring point, the selectable temperature change rate, the duration in the phase change temperature zone, the cumulative heat storage and release, and historical operating data, it determines or estimates the solid, phase change, or liquid state of each vertical heat storage zone and forms a control mapping between each vertical heat storage zone and the corresponding heating section.

[0013] The controller is specifically configured to: determine or estimate the thermal state of the corresponding vertical thermal storage zone based on the temperature information of each vertical thermal storage zone; when the temperature of the upper vertical thermal storage zone is detected to be higher than that of the lower vertical thermal storage zone and the lower vertical thermal storage zone has not reached the melting completion condition during thermal storage startup, make the output power of the heating section corresponding to the lower vertical thermal storage zone greater than the output power of the heating section corresponding to the upper vertical thermal storage zone, or stop the heating section corresponding to the upper vertical thermal storage zone while keeping the heating section corresponding to the lower vertical thermal storage zone working; after the lower vertical thermal storage zone reaches the melting completion condition and / or the vertical temperature difference decreases to a preset value, gradually increase the output power of the heating section corresponding to the upper vertical thermal storage zone.

[0014] Specifically, according to the present invention, when a stratified state of high temperature at the top and low temperature at the bottom is formed after random heat release, the controller prioritizes allocating higher power to the heating section corresponding to the lower low temperature or solid region, and restricts or shuts down the heating section corresponding to the upper high temperature liquid region; if the upper region reaches the upper limit of safe temperature, only its corresponding heating section is reduced or stopped, while the middle and lower heating sections that have not reached the upper limit of safe temperature continue to work. After the lower region reaches the melting completion condition, the vertical temperature difference decreases, or the overall thermal state tends to be balanced, the power of the upper heating section is continuously or stepwise increased until each region reaches the target heat storage state.

[0015] In one embodiment, the phase change temperature range of the phase change thermal storage material is 100℃ to 300℃. During the thermal storage process, the temperature of each vertical thermal storage zone is controlled by the controller to be limited below the upper limit of the safe temperature of the phase change thermal storage material. The upper limit of the safe temperature is lower than the thermal decomposition temperature of the phase change thermal storage material, and a predetermined safety margin is set between the upper limit of the safe temperature and the thermal decomposition temperature.

[0016] In one embodiment, each segmented armored electric heater is provided with an upper heating section, a middle heating section and a lower heating section in sequence along the vertical direction, and the insulated heat storage tank is defined accordingly as an upper heat storage zone, a middle heat storage zone and a lower heat storage zone along the height direction, and there is no physical isolation between the heat storage zones.

[0017] In one embodiment, each segmented armored electric heater penetrates into the tank through a single installation position located at the top of the insulated thermal storage tank, and the lead wires of each heating segment are all led out from the top of the heater, so that the same segmented armored electric heater can achieve vertical partitioned heating without increasing the number of installation openings at different heights of the tank. The segmented armored electric heater includes a metal armored shell, multiple independent heating wires disposed within the metal armored shell, insulating and thermally conductive filler filling the space between the independent heating wires and the metal armored shell, an insulating isolation structure disposed between adjacent heating sections, and a sealed terminal disposed at the top.

[0018] In one embodiment, the heat exchange coil assembly is arranged between adjacent segmented armored electric heaters, with its water inlet located on the lower side of the insulated thermal storage tank and its steam outlet located on the upper side of the same side as the water inlet. During the heat release phase, the water flows from bottom to top within the coil and absorbs the sensible and latent heat of the phase change material to form steam output. When heat release stops, the controller saves the stratified temperature information as the basis for the initial power allocation of the next heat storage cycle.

[0019] In one embodiment, the heat exchange coil assembly includes at least two stainless steel coils connected in parallel or in groups of parallel, the stainless steel coils extending back and forth in the vertical direction and arranged in an alternating array with the segmented armored electric heater in the horizontal direction.

[0020] In one embodiment, the layered temperature sensing component has at least one temperature measuring point in each vertical thermal storage zone; the controller determines or estimates the solid, phase-change or liquid state of the corresponding vertical thermal storage zone based on at least one of the temperature of each temperature measuring point, the rate of temperature change, the duration within the phase change temperature range, and historical data of thermal storage and release.

[0021] The present invention also provides a method for regulating the heat storage of the device, comprising the following steps: S1. When the thermal storage is started, collect the temperature data of the layered structure along the height direction inside the thermal storage tank, and compare the temperature of each vertical thermal storage zone with the phase change temperature range, target thermal storage temperature and upper limit of safe temperature of the phase change thermal storage material to determine or estimate the thermal state of each vertical thermal storage zone. S2. When there is a stratified state where the upper vertical thermal storage zone is a high-temperature liquid phase zone and the lower vertical thermal storage zone is a low-temperature solid phase zone or an incompletely melted zone, increase the output power of the heating section corresponding to the lower vertical thermal storage zone and limit the output power of the heating section corresponding to the upper vertical thermal storage zone to a level lower than the output power of the heating section corresponding to the lower vertical thermal storage zone, or shut down the heating section corresponding to the upper vertical thermal storage zone. S3. While keeping the heating section corresponding to the lower vertical thermal storage zone working, monitor the temperature of each vertical thermal storage zone in real time; when the temperature of any vertical thermal storage zone reaches the upper limit of the safe temperature, reduce or stop the output power of the heating section corresponding to that vertical thermal storage zone, and keep the other heating sections that have not reached the upper limit of the safe temperature working. S4. When the lower vertical thermal storage zone reaches the melting completion condition and / or the temperature difference between the upper vertical thermal storage zone and the lower vertical thermal storage zone is less than the preset equilibrium threshold, the output power of the corresponding heating section of the upper vertical thermal storage zone is increased in a continuous or stepwise manner. S5. Continue heating until each vertical thermal storage zone reaches the target thermal storage state, then switch to heat preservation operation.

[0022] In one embodiment, the melting completion conditions include: the temperature of the corresponding vertical heat storage zone reaching above the liquidus temperature of the phase change heat storage material, and / or the liquid phase ratio of the vertical heat storage zone reaching a preset value based on the cumulative input heat of the vertical heat storage zone.

[0023] In one embodiment, when the temperature of a certain vertical thermal storage zone reaches the upper limit of the safe temperature or the heating rate exceeds the preset value, the power of the corresponding heating section of the vertical thermal storage zone is reduced, and the power of the adjacent heating section is selectively reduced according to the temperature status of the adjacent vertical thermal storage zones, instead of directly stopping all segmented armored electric heaters.

[0024] In one embodiment, during the heat release phase, feedwater enters the heat exchange coil group from the feedwater inlet at the bottom of the heat exchange coil group, absorbs heat from the phase change thermal storage material, forms steam, and is output from the steam outlet at the top of the heat exchange coil group; when heat release stops, the temperature information of each vertical thermal storage zone is recorded, and the temperature information is used as the basis for the initial allocation of thermal storage power in the next cycle; when the steam load fluctuates, the heating section corresponding to the low-temperature vertical thermal storage zone is selectively activated for supplementary heating.

[0025] Compared with the prior art, the beneficial effects of the present invention are: (1) The segmented armored electric heater of the present invention divides the same vertical armored straight pipe into multiple independent heating sections along the axial direction and establishes a corresponding relationship with the vertical heat storage zones inside the tank, so that differentiated heating can be implemented according to the actual thermal state after random heat release. Moreover, unlike the existing method of partitioning through mechanical structure, all phase change heat storage materials in the present invention are a unified whole, which does not require physical partitioning, but is defined only by the corresponding positional relationship with the heating section. Its cost is lower and does not affect the control effect.

[0026] (2) The control method of the present invention can limit or shut down the upper heating section when the upper high temperature region is close to the upper limit of the safe temperature, while keeping the lower low temperature region heated, so as to avoid the premature termination of the entire heat storage process due to local high temperature.

[0027] (3) The present invention prioritizes inputting heat into the lower solid or incompletely melted region, which is beneficial to improving the melting degree of the lower phase change material, the effective utilization rate of the phase change material, and the available heat storage of the device.

[0028] (4) The present invention utilizes an integrated vertical tube to complete multi-height zone heating. Compared with setting multiple short heating tubes at different heights of the tank, it can reduce the openings of the high-temperature tank and the corresponding sealing and insulation structures.

[0029] (5) The partitioned temperature constraint and segmented power input of the present invention can reduce local overheating and excessive vertical temperature gradient, which is beneficial to improving the reliability of the cyclic operation of phase change materials, heaters and tanks. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of the thermal storage steam generator of the present invention.

[0031] Figure 2 This is a top view of the segmented armored electric heater and heat exchange coil array of the present invention.

[0032] Figure 3 This is an axial sectional view and a schematic diagram of the cross-sectional structure of the segmented armored electric heater of the present invention.

[0033] Figure 4 This is a flowchart of the thermal storage regulation method of the present invention.

[0034] In the diagram: 1. Insulated thermal storage tank; 2. Phase change thermal storage material; 21. Upper thermal storage zone; 22. Middle thermal storage zone; 23. Lower thermal storage zone; 3. Segmented armored electric heater; 31. Upper heating section; 32. Middle heating section; 33. Lower heating section; 34. Insulation and isolation structure; 35. Independent heating wire; 36. Metal armored shell; 37. Insulating and thermally conductive filler; 38. Lead wire; 39. Sealed terminal; 4. Heat exchange coil assembly; 41. Water inlet; 42. Steam outlet; 51. Upper temperature sensor; 52. Middle temperature sensor; 53. Lower temperature sensor; 6. Controller; 7. Independent power adjustment component. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the following embodiments are used to illustrate the technical concept of the present invention and are not intended to limit the scope of protection of the present invention; the number of heating sections, section lengths, number of sensors, power adjustment methods, and coil arrangement can all be adjusted accordingly without departing from the concept of the present invention.

[0036] like Figure 1 and Figure 2As shown, the insulated thermal storage tank 1 in this embodiment has a rectangular structure, filled with phase change thermal storage material 2, and an insulation layer is provided on the outside of the tank. The phase change thermal storage material 2 can be a mixture of nitrates, nitrites, or other inorganic salts suitable for the target temperature range, with a phase change temperature in the range of 100℃ to 300℃. In actual operation, the thermal decomposition temperature of the material will be considered. T d Set a safe upper temperature limit. T max , T max Less than T d And maintain a safety margin; target thermal storage temperature T tar Not higher than T max .

[0037] Multiple segmented armored electric heaters 3 are vertically inserted downwards from the top of the tank and arranged in a regular or irregular array in the horizontal direction. Heat exchange coil groups 4 are arranged between adjacent heaters and between the heaters and the inner wall of the tank, and can be multiple stainless steel coils connected in parallel or in groups in parallel. The water inlet 41 is located at the lower part of the same side wall of the tank, and the steam outlet 42 is located at the upper part of the same side wall, so that the water in the coils flows from bottom to top.

[0038] like Figure 3 As shown, taking a three-section segmented armored electric heater 3 as an example, its interior is arranged vertically in the form of an upper heating section 31, a middle heating section 32, and a lower heating section 33. Each heating section includes an independent heating wire 35; the space between the independent heating wire 35 and the metal armor shell 36 is densely filled with insulating and thermally conductive filler 37 such as magnesium oxide, and an insulating isolation structure 34 formed by magnesium oxide ceramic or other high-temperature resistant insulating materials is provided between adjacent heating sections. The lead wires 38 of each section are led out from the top of the heater through the sealed terminal 39 and connected to the independent power adjustment assembly 7 respectively.

[0039] Each heating section can have the same or different axial lengths and rated power. When the heat exchange load at the bottom of the tank is large or when a solid region is more likely to form after heat release, the lower heating section 33 can have a larger rated power or a longer effective heating length; alternatively, while maintaining the same rated power for each section, the duty cycle, conduction angle, or switching cycle of each section can be dynamically adjusted by the controller 6. The independent power adjustment component 7 can use solid-state relays, thyristor power regulators, frequency converters, or other power electronic devices capable of independently switching on and off and adjusting the power of each heating section.

[0040] The tiered temperature sensing components are arranged along the height of the tank. In the three-zone structure, upper temperature sensor 51, middle temperature sensor 52, and lower temperature sensor 53 can be installed in the upper heat storage zone 21, the middle heat storage zone 22, and the lower heat storage zone 23, respectively. To reduce single-point measurement deviation, two or more temperature measuring points can be set at different horizontal positions in each height layer; the controller 6 can use the highest temperature, average temperature, or representative temperature after outlier removal from the measuring points of that layer for control.

[0041] Controller 6 can be a PLC, industrial computer, embedded controller, or other industrial control equipment. Let the solidification temperature of phase change thermal storage material 2 be... T s Melting temperature is T l The upper limit of safe temperature is T max The target thermal storage temperature is T tar Controller 6 will assign the temperature to each zone. T i and T s , T l , T max and T tar Comparison, and can be combined with the temperature rise rate d T i / d t The duration above Tl and the cumulative input or output heat are used to estimate the phase state of each zone. For example, when T i Below T s When this occurs, the partition is classified as a solid-state or low-temperature region; when T i In T s and T l When the phase transition occurs, it is considered to be in the phase transition region; when... T i achieve T l If the temperature remains above the preset value for the above time, it is considered to be basically melted.

[0042] During the heat release phase, all heating sections can be stopped or placed in a low-power standby state. Feedwater enters the heat exchange coil group 4 through feedwater inlet 41, flows upward within the coil, and absorbs heat from the phase change thermal storage material 2. Steam is output from steam outlet 42. Since the lower part of the coil first contacts the low-temperature feedwater, and the user may stop using steam at any time, the tank may reach the following state at the end of the heat release phase: the upper thermal storage zone 21 remains a relatively high-temperature liquid, the middle thermal storage zone 22 is in a phase change or transition state, and the lower thermal storage zone 23 has solidified or has a significantly lower temperature.

[0043] refer to Figure 4 Upon receiving the thermal storage start command under the aforementioned conditions, controller 6 first reads the temperature of each height level. If the lower temperature... T Below T s Or the liquidus temperature has not been reached. T l The upper temperature T It is close to T tar or T max The controller 6 will then operate the lower heating section 33 at a higher power, for example, 80% to 100% of the rated power; the middle heating section 32 will operate at 40% to 100% of the rated power depending on the thermal state of the middle section; and the upper heating section 31 will be shut off or maintained at only 0% to 30% of the rated power. The above power ranges are only examples and can be adjusted according to the tank structure, material properties, and power supply conditions.

[0044] During the heating process, controller 6 continuously monitors the highest temperature of each zone. When the temperature of the upper heat storage zone 21 reaches... T max If the temperature rise rate exceeds the preset value, the controller 6 only reduces or stops the upper heating section 31, while keeping the middle heating section 32 and the lower heating section 33 working; similarly, when the middle area approaches the safety limit, the power of the middle heating section 32 is reduced. This avoids the situation where the lower solid material cannot continue to melt due to the traditional method of shutting down the entire heater at once.

[0045] When the representative temperature of thermal storage zone 23 reaches T l After a preset time has elapsed, or when the liquid phase ratio reaches a preset value based on the accumulated heat input, and the temperature difference between the upper and lower sections decreases to a set threshold within, for example, a range of 5°C to 30°C, the controller 6 begins to increase the power of the upper heating section 31 in a continuous ramp or step manner. The system re-evaluates the process after each power increase. T max The heating is controlled until each zone reaches the target thermal storage temperature and the allowable temperature difference range, after which heating is stopped or switched to insulation mode.

[0046] In another embodiment, the segmented armored electric heater 3 has only two heating sections, upper and lower, which is suitable for heat storage tanks with relatively small heights. In other embodiments, four or more heating sections can be provided to improve the adjustment resolution of the vertical temperature field. The number of heating sections can be the same as the number of temperature sensing layers, or multiple temperature sensing layers can share a single heating section.

[0047] In another embodiment, the controller 6 can estimate the remaining heat in each zone based on the temperature of each zone saved at the end of heat release, the duration of heat release, the feed water flow rate, and the steam flow rate, and directly generate the initial power allocation before the next heat storage begins; during the heat storage process, real-time temperature feedback is used for correction. In the event of a short-term increase in steam load, the heating section corresponding to the zone with the lower temperature can be selectively activated for supplementary heating to reduce the risk of local overheating in the high-temperature zone.

[0048] As can be seen from the above embodiments, the core of the present invention is not limited to a certain formula, a fixed number of segments, or a fixed power ratio, but rather to: dividing the vertical straight tube armored electric heater into multiple independent and controllable heating segments along the axial direction, establishing a correspondence between each heating segment and the vertical thermal state partitions inside the tank, and selectively allocating power according to the actual temperature and solid-liquid state distribution formed after random heat release, so that the low-temperature partition can continue to be heated while the high-temperature partition is safely constrained.

Claims

1. A phase change thermal storage steam generator, characterized in that, It includes an insulated thermal storage tank (1), an integral phase change thermal storage material (2) filled in the insulated thermal storage tank (1), multiple segmented armored electric heaters (3), heat exchange coil assembly (4), layered temperature sensing components, controller (6), and independent power adjustment components (7). The segmented armored electric heater (3) is a straight tube heater that is vertically inserted from the top of the heat storage tank (1). Each segmented armored electric heater (3) has at least two heating sections that are electrically isolated from each other along the axial direction. Each heating section is connected to the independent power adjustment component (7) through an independent power supply circuit so as to independently start and stop and adjust the output power. The insulated heat storage tank (1) is defined along the height direction as at least two vertical heat storage zones corresponding to the heating section. The heat exchange coil group (4) is arranged inside the tank. The layered temperature sensing component is used to obtain the temperature information of each vertical heat storage zone. The controller (6) is connected to the layered temperature sensing component and the independent power adjustment component (7) respectively, and is configured to: determine or estimate the thermal state of the corresponding vertical heat storage zone based on the temperature information of each vertical heat storage zone; when the temperature of the upper vertical heat storage zone is detected to be higher than that of the lower vertical heat storage zone when the heat storage is started, and the lower vertical heat storage zone has not reached the melting completion condition, make the output power of the heating section corresponding to the lower vertical heat storage zone greater than the output power of the heating section corresponding to the upper vertical heat storage zone, or stop the heating section corresponding to the upper vertical heat storage zone while keeping the heating section corresponding to the lower vertical heat storage zone working; after the lower vertical heat storage zone reaches the melting completion condition and / or the vertical temperature difference decreases to a preset value, gradually increase the output power of the heating section corresponding to the upper vertical heat storage zone.

2. The apparatus according to claim 1, characterized in that, The phase change thermal storage material (2) has a phase change temperature range of 100℃ to 300℃. During the thermal storage process, the temperature of each vertical thermal storage zone is controlled by the controller (6) to be limited below the upper limit of the safe temperature of the phase change thermal storage material (2). The upper limit of the safe temperature is lower than the thermal decomposition temperature of the phase change thermal storage material (2), and a predetermined safety margin is set between the upper limit of the safe temperature and the thermal decomposition temperature.

3. The apparatus according to claim 1, characterized in that, Each segmented armored electric heater (3) is provided with an upper heating section (31), a middle heating section (32) and a lower heating section (33) in the vertical direction. The heat storage tank (1) is defined as an upper heat storage zone (21), a middle heat storage zone (22) and a lower heat storage zone (23) in the height direction. There is no physical isolation between the heat storage zones.

4. The apparatus according to claim 1 or 3, characterized in that, Each segmented armored electric heater (3) penetrates into the tank through a single installation position set at the top of the insulated heat storage tank (1). The lead wires (38) of each heating section are all led out from the top of the heater, so that the same segmented armored electric heater (3) can achieve vertical partition heating without increasing the installation openings at different heights of the tank. The segmented armored electric heater (3) includes a metal armored shell (36), multiple independent heating wires (35) disposed within the metal armored shell (36), insulating thermally conductive filler (37) filling the space between the independent heating wires (35) and the metal armored shell (36), an insulating isolation structure (34) disposed between adjacent heating sections, and a sealed terminal (39) disposed at the top.

5. The apparatus according to claim 1, characterized in that, The heat exchange coil assembly (4) is arranged between adjacent segmented armored electric heaters (3), with its water inlet (41) located on the lower side of the insulated heat storage tank (1) and its steam outlet (42) located on the upper side of the same side as the water inlet (41). The heat exchange coil assembly (4) includes at least two stainless steel coils connected in parallel or in groups, which extend back and forth in the vertical direction and are arranged in an alternating array with the segmented armored electric heaters (3) in the horizontal direction.

6. The apparatus according to claim 1, characterized in that, The layered temperature sensing component has at least one temperature measuring point in each vertical thermal storage zone; the controller (6) determines or estimates the solid, phase change or liquid state of the corresponding vertical thermal storage zone based on at least one of the temperature of each temperature measuring point, the rate of temperature change, the duration in the phase change temperature range and the historical data of thermal storage and release.

7. A method for regulating the heat storage of the device according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. When the thermal storage is started, collect the temperature data of the layered structure along the height direction inside the thermal storage tank (1), and compare the temperature of each vertical thermal storage zone with the phase change temperature range, target thermal storage temperature and safe upper limit of the phase change thermal storage material (2) to determine or estimate the thermal state of each vertical thermal storage zone. S2. When there is a stratified state where the upper vertical thermal storage zone is a high-temperature liquid phase zone and the lower vertical thermal storage zone is a low-temperature solid phase zone or an incompletely melted zone, increase the output power of the heating section corresponding to the lower vertical thermal storage zone and limit the output power of the heating section corresponding to the upper vertical thermal storage zone to a level lower than the output power of the heating section corresponding to the lower vertical thermal storage zone, or shut down the heating section corresponding to the upper vertical thermal storage zone. S3. While keeping the heating section corresponding to the lower vertical thermal storage zone working, monitor the temperature of each vertical thermal storage zone in real time; when the temperature of any vertical thermal storage zone reaches the upper limit of the safe temperature, reduce or stop the output power of the heating section corresponding to that vertical thermal storage zone, and keep the other heating sections that have not reached the upper limit of the safe temperature working. S4. When the lower vertical thermal storage zone reaches the melting completion condition and / or the temperature difference between the upper vertical thermal storage zone and the lower vertical thermal storage zone is less than the preset equilibrium threshold, the output power of the corresponding heating section of the upper vertical thermal storage zone is increased in a continuous or stepwise manner. S5. Continue heating until each vertical thermal storage zone reaches the target thermal storage state, then switch to heat preservation operation.

8. The thermal energy storage regulation method according to claim 7, characterized in that, The melting completion conditions include: the temperature of the corresponding vertical heat storage zone reaches above the liquidus temperature of the phase change heat storage material (2), and / or the liquid phase ratio of the vertical heat storage zone is determined to reach a preset value based on the cumulative input heat of the vertical heat storage zone.

9. The thermal energy storage regulation method according to claim 7, characterized in that, When the temperature of a certain vertical thermal storage zone reaches the upper limit of the safe temperature or the heating rate exceeds the preset value, the power of the corresponding heating section of the vertical thermal storage zone is reduced, and the power of the adjacent heating section is selectively reduced according to the temperature status of the adjacent vertical thermal storage zones, instead of directly stopping all the segmented armored electric heaters (3).

10. The thermal energy storage regulation method according to claim 7, characterized in that, During the heat release phase, feedwater enters the heat exchange coil group (4) through the feedwater inlet (41) at the bottom of the heat exchange coil group (4), absorbs the heat from the phase change thermal storage material (2), forms steam, and is output through the steam outlet (42) at the top of the heat exchange coil group (4); when the heat release stops, the temperature information of each vertical thermal storage zone is recorded, and the temperature information is used as the basis for the initial allocation of thermal storage power in the next cycle; when the steam load fluctuates, the heating section corresponding to the low temperature vertical thermal storage zone is selectively started for supplementary heating.

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