Solid oxide electrolysis cell system hot box for ensuring thermal stability of solid oxide electrolysis cell stack
A dummy stack in the hot box of high-temperature water electrolysis systems addresses temperature imbalances by acting as a thermal buffer, ensuring stable temperature gradients and enhancing stack durability and efficiency.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- POSCO HLDG INC
- Filing Date
- 2025-12-18
- Publication Date
- 2026-06-25
AI Technical Summary
Conventional hot boxes for high-temperature water electrolysis systems suffer from uneven temperature distribution, leading to thermal stress, performance variations, and reduced durability of electrolysis stacks, which affects energy efficiency and economic viability.
Incorporation of a dummy stack within the hot box to act as a thermal buffer, controlling temperature distribution by positioning it at a specific distance from the gas inlet and using temperature sensors to manage the heating process, ensuring a stable temperature gradient between the dummy and electrolysis stacks.
The dummy stack mitigates rapid temperature changes, prevents physical damage, and maintains optimal operating conditions, enhancing the durability and efficiency of the electrolysis stacks, thereby improving the overall system's thermal stability and hydrogen production.
Smart Images
Figure KR2025022173_25062026_PF_FP_ABST
Abstract
Description
Hot box for high-temperature water electrolysis systems to ensure thermal stability of high-temperature water electrolysis stacks
[0001] The present invention relates to a Solid Oxide Electrolysis Cell (SOEC) system, and more specifically, to a hot box for a Solid Oxide Electrolysis Cell system that enables a Solid Oxide Electrolysis Cell stack to operate stably within an optimal temperature range.
[0002] High-temperature water electrolysis systems are a core technology for hydrogen production, performing an electrochemical process that decomposes water into hydrogen and oxygen through an electrolysis stack. In such high-temperature water electrolysis systems, the hot box is a key piece of equipment that includes major components, such as the electrolysis stack module, heat exchangers, and heaters.
[0003] Since the high-temperature water electrolysis stack must operate in a high-temperature environment due to its characteristics, the hot box must stably provide a high-temperature environment for the normal operation of the stack. To this end, the hot box is operated by receiving high-temperature gas heated through a gas heater to raise its internal temperature.
[0004] Conventional hot boxes for high-temperature water electrolysis systems face various technical problems due to the uneven distribution of high-temperature gas entering from the gas inlet. A temperature imbalance occurs where stacks located near the gas inlet are exposed to rapid temperature changes, resulting in excessive thermal stress, while stacks located far from the gas inlet operate at relatively lower temperatures.
[0005] Such temperature imbalances not only cause performance variations between stacks but also negatively affect the durability of individual stacks. Stacks exposed to rapid temperature changes may suffer physical damage due to thermal shock, which is a major cause of shortened stack lifespan.
[0006] If temperature gradients within the hot box cause differences in operating temperatures between stacks, the overall energy efficiency of the system decreases, and stable hydrogen production becomes difficult. Consequently, this acts as a factor that undermines the economic viability and reliability of the high-temperature water electrolysis system.
[0007] Existing hot box systems lack a mechanism to effectively control internal temperature distribution, which limits their ability to respond to rapid temperature changes during startup and shutdown processes. This results in restricted operational flexibility and increased maintenance costs.
[0008] Accordingly, to improve the performance and reliability of the high-temperature water electrolysis system, a new technical solution is required that can uniformly control the temperature distribution inside the hot box and ensure the thermal stability of each stack.
[0009] By providing one aspect of the present invention, we aim to provide a hot box for a high-temperature water electrolysis system that can resolve the temperature imbalance occurring inside the hot box of the high-temperature water electrolysis system and ensure the thermal stability of the stack.
[0010] By providing another aspect of the present invention, we aim to provide a hot box for a high-temperature water electrolysis system that can prevent physical damage to the stack and extend its lifespan by mitigating rapid temperature changes occurring near the gas inlet.
[0011] By providing another aspect of the present invention, we aim to provide a hot box for a high-temperature water electrolysis system that effectively controls the temperature distribution inside the hot box, thereby improving the energy efficiency of the system and enabling stable hydrogen production.
[0012] According to one aspect of the present invention, a hot box for a high-temperature water electrolysis system for securing thermal stability of a high-temperature water electrolysis stack comprises: a gas inlet, a dummy stack disposed inside the hot box, and a high-temperature water electrolysis stack, wherein the gas inlet supplies high-temperature gas heated by a gas heater into the hot box, the difference between the temperature of the heated high-temperature gas and the temperature of the dummy stack is greater than or equal to the difference between the temperature of the dummy stack and the high-temperature water electrolysis stack, and the temperature inside the hot box is 650 to 800 o A hot box for a high-temperature water electrolysis system can be provided, characterized by indicating a temperature of C.
[0013] For example, a hot box for a high-temperature water electrolysis system may be provided, characterized in that a dummy stack is positioned at a first distance from the gas inlet, and a high-temperature water electrolysis stack is positioned at a second distance greater than the first distance from the gas inlet.
[0014] For example, in a dummy stack, the temperature gradient between the dummy stack and the high-temperature water electrolysis stack is 5 per hour o By ensuring a change of C or less, the operating temperature of the high-temperature water electrolysis stack is set to 650 to 800 o A hot box for a high-temperature water electrolysis system characterized by maintaining C.
[0015] For example, a hot box for a high-temperature water electrolysis system may be provided, characterized by further including: a heat exchanger for controlling the temperature of a high-temperature gas; and an insulating material.
[0016] For example, the hot box additionally includes a temperature control unit, the dummy stack is equipped with a dummy stack temperature sensor, the high-temperature water electrolysis stack is equipped with a high-temperature water electrolysis stack temperature sensor, and the temperature control unit is characterized by reducing the heating temperature of the gas heater when the temperature difference value measured by the dummy stack temperature sensor and the high-temperature water electrolysis stack temperature sensor exceeds a preset threshold value.
[0017] A hot box for a high-temperature water electrolysis system can be provided.
[0018] For example, a preset threshold is 30 to 50 o A hot box for a high-temperature water electrolysis system can be provided, characterized by being a temperature selected from C.
[0019] For example, a hot box for a high-temperature water electrolysis system may be provided, wherein the hot box comprises a plurality of high-temperature water electrolysis stacks, and the plurality of high-temperature water electrolysis stacks are arranged such that their distances from the gas inlet are different from each other, and the second distance is the distance between the high-temperature water electrolysis stack closest to the gas inlet among the plurality of high-temperature water electrolysis stacks and the gas inlet, and the dummy stack is arranged closer to the gas inlet than the high-temperature water electrolysis stack closest to the gas inlet among the plurality of high-temperature water electrolysis stacks.
[0020] For example, a hot box for a high-temperature water electrolysis system may be provided, wherein the dummy stack and the high-temperature water electrolysis stack are formed of the same material, but the dummy stack is characterized by not having electrodes formed thereon.
[0021] For example, a hot box for a high-temperature water electrolysis system may be provided, wherein the dummy stack comprises a plurality of detailed dummy stacks, the first distance is the distance between the dummy stack closest to the gas inlet among the plurality of dummy stacks and the gas inlet, and the plurality of dummy stacks are disposed between the gas inlet and the high-temperature water electrolysis stack.
[0022] For example, a hot box for a high-temperature water electrolysis system may be provided, characterized in that the spacing between multiple dummy stacks is arranged equally.
[0023] According to one aspect of the present invention, a hot box for a high-temperature water electrolysis system can be provided in which temperature imbalance is eliminated and thermal stability of the stack is ensured by placing a dummy stack inside the hot box of the high-temperature water electrolysis system.
[0024] According to another aspect of the present invention, a hot box for a high-temperature water electrolysis system can be provided in which physical damage to the stack is prevented and the lifespan is extended as a sudden temperature change occurring near the gas inlet is mitigated by a dummy stack.
[0025] According to another aspect of the present invention, a hot box for a high-temperature water electrolysis system can be provided, in which the temperature distribution inside the hot box is effectively controlled through a dummy stack, thereby improving the energy efficiency of the system and enabling stable hydrogen production.
[0026] FIG. 1 is a schematic diagram showing the configuration of a hot box for a high-temperature water electrolysis system according to one embodiment of the present invention.
[0027] Hereinafter, preferred embodiments of the present invention will be described with reference to the attached drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.
[0028] According to one aspect of the present invention, a hot box (100) for a high-temperature water electrolysis system for securing thermal stability of a high-temperature water electrolysis stack (300) comprises: a gas inlet (110), a dummy stack (200) disposed inside the hot box (100), and a high-temperature water electrolysis stack (300); the gas inlet (110) supplies high-temperature gas heated by a gas heater (120) into the hot box (100); the temperature difference between the heated high-temperature gas and the dummy stack (200) is greater than or equal to the temperature difference between the dummy stack (200) and the high-temperature water electrolysis stack (300); and the temperature inside the hot box (100) is 650 to 800 o A hot box (100) for a high-temperature water electrolysis system, characterized by indicating a temperature of C, may be provided.
[0029] FIG. 1 is a schematic diagram showing the configuration of a hot box for a high-temperature water electrolysis system according to an embodiment of the present invention, illustrating a hot box (100) for a high-temperature water electrolysis system according to an embodiment of the present invention. Referring to FIG. 1, the hot box (100) includes a gas inlet (110), a gas heater (120), a dummy stack (200), and a high-temperature water electrolysis stack (300). The dummy stack (200) is positioned at a first distance (D1) from the gas inlet (110), and the high-temperature water electrolysis stack (300) is positioned at a second distance (D2) greater than the first distance (D1) from the gas inlet (110). To measure the temperatures of the dummy stack (200) and the high-temperature water electrolysis stack (300), a dummy stack temperature sensor (610) and a high-temperature water electrolysis stack temperature sensor (620) are provided, respectively.
[0030] In this configuration, the high-temperature gas supplied from the gas heater (120) is transferred to the high-temperature water electrolysis stack (300) via the dummy stack (200). The dummy stack (200) acts as a thermal buffering means to mitigate rapid temperature changes from the high-temperature gas, thereby enabling the high-temperature water electrolysis stack (300) to operate within a stable temperature range.
[0031] A hot box (100) for a high-temperature water electrolysis system may be configured to include a gas inlet (110), a dummy stack (200), and a high-temperature water electrolysis stack (300). In this configuration, the dummy stack (200) may be placed between the gas inlet (110) and the high-temperature water electrolysis stack (300) to enable a thermal buffering function. The dummy stack (200) may act as a thermal buffering means to mitigate rapid temperature changes from the high-temperature gas.
[0032] The gas inlet (110) is connected to a gas heater (120) and can perform the function of supplying high-temperature gas into the hot box (100). The high-temperature gas supplied from the gas heater (120) can function as a heat source to raise the temperature inside the hot box (100). By setting the temperature difference between the high-temperature gas and the dummy stack (200) to be greater than or equal to the temperature difference between the dummy stack (200) and the high-temperature water electrolysis stack (300), the dummy stack (200) can preferentially absorb sudden thermal shock from the high-temperature gas. Through this configuration, the effect of protecting the high-temperature water electrolysis stack (300) can be achieved.
[0033] By placing a dummy stack (200) between the gas inlet (110) and the high-temperature water electrolysis stack (300), this temperature range can be stably maintained inside the hot box (100). That is, the dummy stack (200) primarily absorbs the heat of the high-temperature gas and gradually releases it, thereby ensuring temperature uniformity in the space where the high-temperature water electrolysis stack (300) is located.
[0034] The interior of the hot box (100) is 650 to 800 o C, 670 to 780 o C, 680 to 760 o C, or 700 to 750 o It can be maintained within a temperature range of C. This temperature range can provide optimal operating conditions for the high-temperature water electrolysis stack (300). Specifically, this temperature range may be an optimal condition for ensuring the durability of the stack while maximizing the efficiency of the high-temperature water electrolysis reaction. Heat distribution through the dummy stack (200) can contribute to ensuring that this temperature range is stably maintained inside the hot box (100).
[0035] The high-temperature water electrolysis stack (300) may be a key component that performs an electrochemical reaction to decompose water into hydrogen and oxygen in a high-temperature environment. In addition to mitigating rapid temperature changes of the high-temperature gas, the dummy stack (200) may also function to optimize the gas flow inside the hot box (100). The gas flow controlled by the dummy stack (200) can form a more uniform temperature distribution around the high-temperature water electrolysis stack (300), which can lead to an improvement in the overall thermal stability of the system.
[0036] The dummy stack (200) can perform the function of optimizing the gas flow inside the hot box (100) along with a thermal buffering function. The gas flow controlled by the dummy stack (200) can form a more uniform temperature distribution around the high-temperature water electrolysis stack (300), which can lead to improved efficiency of the high-temperature water electrolysis reaction and ensure overall thermal stability of the system. By configuring the dummy stack (200) to be placed between the gas inlet (110) and the high-temperature water electrolysis stack (300) in this manner, stable operation of the high-temperature water electrolysis system can be achieved.
[0037] For example, a hot box (100) for a high-temperature water electrolysis system may be provided, characterized in that a dummy stack (200) is positioned at a first distance (D1) from the gas inlet (110), and a high-temperature water electrolysis stack (300) is positioned at a second distance (D2) greater than the first distance (D1) from the gas inlet (110).
[0038] The distance between the dummy stack (200) and the high-temperature water electrolysis stack (300) can be an important design element for ensuring thermal stability. The dummy stack (200) can be placed at a first distance (D1) from the gas inlet (110), and the high-temperature water electrolysis stack (300) can be placed at a second distance (D2) greater than the first distance (D1). Through this difference in distance, the heat of the high-temperature gas can be preferentially absorbed by the dummy stack (200) and then transferred to the high-temperature water electrolysis stack (300), which can effectively mitigate the thermal shock received by the high-temperature water electrolysis stack (300). In addition, this arrangement allows a gradual temperature gradient to be formed inside the hot box (100), thereby ensuring that the operating temperature of the high-temperature water electrolysis stack (300) can be maintained stably.
[0039] For example, the dummy stack (200) may be positioned at a distance of 100 mm to 300 mm (first distance (D1)) from the gas inlet (110), and the high-temperature water electrolysis stack (300) may be positioned at a distance of 400 mm to 800 mm (second distance (D2)) from the gas inlet (110). These distance settings allow the high-temperature gas to obtain a sufficient thermal buffering effect as it passes through the dummy stack (200), while simultaneously allowing the high-temperature water electrolysis stack (300) to maintain an appropriate operating temperature.
[0040] For example, the dummy stack (200) has a temperature gradient between the dummy stack (200) and the high-temperature water electrolysis stack (300) of 5 per hour. o By showing a change of C or less, the operating temperature of the high-temperature water electrolysis stack (300) is set to 650 to 800 o A hot box (100) for a high-temperature water electrolysis system, characterized by maintaining C, may be provided.
[0041] For example, the dummy stack (200) is 700 when high-temperature gas first flows into the hot box (100). oIt primarily absorbs high-temperature gas of C or higher to lower the temperature of the gas flowing into the hot box (100), and depending on the distance from the dummy stack (200) to the high-temperature water electrolysis stack (300), 10 to 30 per unit distance o C, 12 to 28 o C, 15 to 25 o C, or 18 to 22 o It can release absorbed heat to form a temperature gradient of C.
[0042] For example, the dummy stack (200) has a temperature gradient occurring in the space between the dummy stack (200) and the high-temperature water electrolysis stack (300) of 5 per hour. o C or less, 4 o C or less, 3 o C or less, 2 o C or less, or 1 o By showing a change of C or less, the operating temperature of the high-temperature water electrolysis stack (300) is set to 650 to 800 o It can be maintained stably with C.
[0043] The thermal buffering of the dummy stack (200) can be achieved through a specific temperature control mechanism. The dummy stack (200) is 700 o When high-temperature gas of C or higher first flows into the hot box (100), it can be primarily absorbed to lower the temperature. Subsequently, the dummy stack (200) releases the absorbed heat, and depending on the distance from the dummy stack (200) to the high-temperature water electrolysis stack (300), 10 to 30 per unit distance o A temperature gradient of C can be formed. This temperature gradient is 5 per hour o The operating temperature of the high-temperature water electrolysis stack (300) can be maintained at a rate of change of C or less, so that it is 650 to 800 o C, 670 to 780 o C, 680 to 760 o C, or 700 to 750 oIt can be maintained stably at C. Such a gradual and controlled heat transfer process can significantly improve the thermal stability of the high-temperature water electrolysis stack (300).
[0044] For example, the temperature of the initial incoming high-temperature gas is 700~800 o In the case of C. The temperature can be lowered by the dummy stack (200), and then while reaching the high-temperature water electrolysis stack (300) located 500 mm away from the dummy stack (200), 15 o A temperature gradient of C / 100mm can be formed, and the hourly rate of change of the temperature gradient is 3 o Since it can be maintained at around C, the high-temperature water electrolysis stack (300) is 725 o It can maintain a stable operating temperature of C.
[0045] For example, when a first dummy stack (200) and a second dummy stack (200) are provided, the gas temperature of the first dummy stack (200) is 50 and the target temperature. o The temperature can be raised by a difference of within C, and the rate of temperature change according to the heater's control output is -50 to +50 relative to the target temperature o It can be measured in C, and the second dummy stack (200) can have its temperature change rate reduced compared to the first dummy stack according to the control output of the heater, and the temperature change rate is between -20 and +20 based on the target temperature. o It can be measured as C.
[0046] For example, a hot box (100) for a high-temperature water electrolysis system may be provided, characterized in that the hot box (100) further comprises: a heat exchanger for controlling the temperature of a high-temperature gas; and an insulating material for preventing heat loss to the outside of the hot box (100).
[0047] To improve the temperature control performance of the hot box (100), a heat exchanger and insulation material may be additionally configured. The heat exchanger can perform the function of adjusting the temperature of the high-temperature gas as needed, and this can be utilized to control the initial temperature of the high-temperature gas flowing into the dummy stack (200). The insulation material can perform the function of preventing heat loss to the outside of the hot box (100), thereby allowing the temperature inside the hot box (100) to be maintained stably. These additional configurations can work in synergy with the thermal buffering effect of the dummy stack (200) to improve the overall thermal stability of the system.
[0048] For example, the heat exchanger is 800 o C to 1000 o C, 825 o C to 975 o C, 850 o C to 950 o C, or 875 o C to 925 o 650°C high-temperature gas o C to 900 o C, 675 o C to 875 o C, 700 o C to 850 o C, or 725 o C to 825 o It can have a capacity that can be freely adjusted within the C range. The insulation is 1000 o C or higher, 1100 o C or higher, 1200 o C or higher, or 1300 oIt may have heat resistance of C or higher and a thermal conductivity of 0.1 W / mK or less, 0.08 W / mK or less, 0.06 W / mK or less, 0.04 W / mK or less, or 0.02 W / mK or less, and the thickness may be set in the range of 50 mm to 150 mm, 60 mm to 140 mm, 70 mm to 130 mm, or 80 mm to 120 mm. These specifications may contribute to effectively controlling and maintaining the temperature inside the hot box (100).
[0049] For example, a hot box (100) for a high-temperature water electrolysis system may be provided, wherein the hot box (100) additionally includes a temperature control unit, the dummy stack (200) is equipped with a dummy stack temperature sensor (610), the high-temperature water electrolysis stack (300) is equipped with a high-temperature water electrolysis stack temperature sensor (620), and the temperature control unit reduces the heating temperature of the gas heater (120) when the temperature difference value measured by the dummy stack temperature sensor (610) and the high-temperature water electrolysis stack temperature sensor (620) exceeds a preset threshold value.
[0050] To improve the precision of temperature control, temperature sensors may be installed in the dummy stack (200) and the high-temperature water electrolysis stack (300), respectively. The temperature difference between the dummy stack (200) and the high-temperature water electrolysis stack (300), measured by these temperature sensors, can be used to control the heating temperature of the gas heater (120). In particular, if the temperature difference exceeds a preset threshold, the heating temperature of the gas heater (120) may be automatically reduced. This feedback control system can prevent the high-temperature water electrolysis stack (300) from being exposed to excessive thermal stress and can enable automated temperature management of the system.
[0051] For example, a temperature sensor is ±1 oIt can have a measurement error within C and a response speed within 0.1 seconds. The measured temperature data can be collected at 1-second intervals and processed in real time, and if the temperature difference value exceeds a threshold value, the output of the gas heater (120) can be automatically reduced by 5% to 15% within 0.5 seconds. Such rapid and precise control can significantly improve the thermal stability of the system.
[0052] For example, the preset threshold is 30 to 50 o A hot box (100) for a high-temperature water electrolysis system may be provided, characterized by being a temperature selected from C.
[0053] The threshold value for the temperature difference between the dummy stack (200) and the high-temperature water electrolysis stack (300) is 30 to 50 o C, 32 to 48 o C, 35 to 45 o C, or 37 to 43 o It can be set to C. The range of such threshold values may be derived by considering the thermal durability and operational efficiency of the high-temperature water electrolysis stack (300). That is, 30 o Temperature differences of less than C can reduce heat transfer efficiency, and 50 o A temperature difference exceeding C can cause excessive thermal stress in the high-temperature water electrolysis stack (300). Therefore, setting this threshold can contribute to achieving stable operation of the system and efficient thermal management at the same time.
[0054] For example, 45 to 50 during the initial operation of the system o C, 46 to 49 o C, 46.5 to 48.5 o C, or 47 to 48 o A relatively high threshold value of C may be applied, and 30 to 35 during normal operation o C, 31 to 34 o C, 31.5 to 33.5 oC, or 32 to 33 o A lower threshold of C may be applied. Also, the external temperature is 20 o If C is less than, the threshold is 40 to 45 o C, 41 to 44 o C, 41.5 to 43.5 o C, or 42 to 43 o It can be adjusted to C, enabling optimized temperature control depending on the system's operating environment.
[0055] For example, a hot box (100) for a high-temperature water electrolysis system may be provided, wherein the hot box (100) includes a plurality of high-temperature water electrolysis stacks (310, 320, ..., 3n0), and the plurality of high-temperature water electrolysis stacks (310, 320, ..., 3n0) are arranged such that their distances from the gas inlet (110) are different from each other, and the second distance (D2) is the distance between the gas inlet (110) and the high-temperature water electrolysis stack (300) that is closest to the gas inlet (110) among the plurality of high-temperature water electrolysis stacks (310, 320, ..., 3n0), and the dummy stack (200) is arranged closer to the gas inlet (110) than the high-temperature water electrolysis stack (300) that is closest to the gas inlet (110) among the plurality of high-temperature water electrolysis stacks (310, 320, ..., 3n0).
[0056] Multiple high-temperature water electrolysis stacks (310, 320, ..., 3n0) may be arranged within the hot box (100), and each high-temperature water electrolysis stack (300) may be located at different distances from the gas inlet (110). In this case, a dummy stack (200) may be placed closer to the gas inlet (110) than the high-temperature water electrolysis stack (300) located closest to the gas inlet (110). Through this arrangement, the dummy stack (200) can preferentially absorb and disperse the heat of the high-temperature gas, which can effectively reduce the temperature difference that may occur between the multiple high-temperature water electrolysis stacks (310, 320, ..., 3n0). As a result, all high-temperature water electrolysis stacks (300) can operate under similar temperature conditions, thereby improving the uniformity of performance of the entire system.
[0057] When a plurality of high-temperature water electrolysis stacks (310, 320, ..., 3n0) are arranged within a hot box (100), a high-temperature water electrolysis stack temperature sensor (620) may be provided in a high-temperature water electrolysis stack (300) that defines a second distance (D2).
[0058] For example, the dummy stack (200) may be located at 180 to 220 mm, 190 to 210 mm, 195 to 205 mm, or 198 to 202 mm from the gas inlet (110), and the first high-temperature water electrolysis stack (300) may be located at 380 to 420 mm, 390 to 410 mm, 395 to 405 mm, or 398 to 402 mm, the second at 580 to 620 mm, 590 to 610 mm, 595 to 605 mm, or 598 to 602 mm, and the third at 780 to 820 mm, 790 to 810 mm, 795 to 805 mm, or 798 to 802 mm.
[0059] Additionally, the dummy stacks (200) may be arranged at equal intervals or at unequal intervals, and such arrangement of dummy stacks (200) may result in a temperature difference of 20 between each stack. o Within C, 15 o Within C, 10 o Within C, or 5 o It can be maintained within C, which allows the overall system performance uniformity to be secured at 90% or more, 92% or more, 95% or more, or 97% or more.
[0060] For example, a hot box (100) for a high-temperature water electrolysis system may be provided, wherein the dummy stack (200) and the high-temperature water electrolysis stack (300) are formed of the same material, but the dummy stack (200) is characterized by not having electrodes formed therein.
[0061] The dummy stack (200) may be formed from the same material as the high-temperature water electrolysis stack (300), but electrodes for the electrochemical reaction may not be formed. The use of the same material allows the dummy stack (200) to have thermal characteristics similar to those of the high-temperature water electrolysis stack (300), thereby enabling the heat absorption and release processes to be carried out more effectively. A structure without electrodes allows the dummy stack (200) to focus purely on the thermal buffering function. This configuration allows the desired thermal buffering effect to be sufficiently achieved while reducing the manufacturing cost of the dummy stack (200).
[0062] For example, both the dummy stack (200) and the high-temperature water electrolysis stack (300) are 800 o It can be made of a ceramic material having heat resistance of C or higher and a thermal conductivity of 15 W / mK or higher. In the case of the dummy stack (200), since no electrodes are formed, the manufacturing cost can be reduced by 40% to 60% compared to the high-temperature water electrolysis stack (300), which can contribute to improving the economic efficiency of the entire system.
[0063] For example, a hot box (100) for a high-temperature water electrolysis system may be provided, wherein the dummy stack (200) includes a plurality of detailed dummy stacks (200), the first distance (D1) is the distance between the dummy stack (200) closest to the gas inlet (110) among the plurality of dummy stacks (210, 220, ..., 2n0) and the gas inlet (110), and the plurality of dummy stacks (210, 220, ..., 2n0) are arranged between the gas inlet (110) and the high-temperature water electrolysis stack (300).
[0064] When a plurality of dummy stacks (210, 220, ..., 2n0) are placed within a hot box (100), a dummy stack temperature sensor (610) may be provided in a high-temperature water electrolysis stack (300) that defines a first distance (D1).
[0065] Dummy stacks (200) may be arranged sequentially in groups of 2 to 10, 3 to 8, 4 to 7, or 5 to 6, and the spacing between them may increase sequentially as they move further away from the gas inlet (110). This multi-stage configuration allows the temperature of the high-temperature gas to be lowered more precisely and in stages. An arrangement that sequentially increases the spacing between dummy stacks (200) allows a temperature gradient to be formed gradually, thereby allowing the heat transfer process to be carried out more stably. Consequently, this allows heat transfer to the high-temperature water electrolysis stack (300) to be carried out in a more uniform and controlled manner, thereby further improving the thermal stability of the system.
[0066] For example, in a small system of 5 kW or less, 2 to 3 dummy stacks (200) may be used, and in a large system of 50 kW or more, 8 to 10 dummy stacks (200) may be used. Each dummy stack (200) may be designed to have a thermal capacity of 1.5 to 2.0 kJ / K, thereby effectively ensuring the thermal stability of the entire system.
[0067] For example, a hot box (100) for a high-temperature water electrolysis system may be provided, characterized in that the spacing between a plurality of dummy stacks (210, 220, ..., 2n0) is arranged equally, or a hot box (100) for a high-temperature water electrolysis system may be provided, characterized in that the spacing between a plurality of dummy stacks (210, 220, ..., 2n0) is arranged to increase sequentially.
[0068] An arrangement that sequentially increases the spacing between multiple dummy stacks (210, 220, ..., 2n0) can allow for more precise control of the formation of the temperature gradient. For example, when the spacing between the first and second dummy stacks (200) is 45 to 55 mm, 47 to 53 mm, 48 to 52 mm, or 49 to 51 mm, the spacing between the second and third dummy stacks (200) can be configured to gradually increase as 70 to 80 mm, 72 to 78 mm, 73 to 77 mm, or 74 to 76 mm, and the spacing between the third and fourth dummy stacks (200) can be configured to gradually increase as 95 to 105 mm, 97 to 103 mm, 98 to 102 mm, or 99 to 101 mm. This sequential increase in the interval can make the temperature gradient more gradual, which can make the heat transfer to the high-temperature water electrolysis stack (300) more stable.
[0069] For example, when using five dummy stacks (200), the first spacing can be set to 50 mm and then increased by 1.5 times, such as 75 mm, 112.5 mm, 168.75 mm, and 253.125 mm, respectively. This exponential increase in spacing can correspond to the heat transfer characteristics where the temperature gradient decreases logarithmically, thereby allowing for a more natural temperature distribution to be formed.
[0070] The present invention will be described in detail below using specific embodiments. It should be understood that the following embodiments are not intended to limit the scope of the invention, but are intended to illustrate the implementation of the invention.
[0071] Examples
[0072] To implement the hot box (100) for the high-temperature water electrolysis system of the present invention, a hot box (100) with dimensions of 1000mm x 1000mm x 1200mm in width x length x height was manufactured. For insulation, a polyurethane foam, wool, or alumina-silica ceramic fiber insulation material having a thermal conductivity of approximately 0.04W / mK was installed to a thickness of 100mm, and a heat exchanger made of materials such as Inconel, Hastelloy, stainless steel, or nickel alloy with a heat transfer surface area of 2.5m² was used inside. The gas heater (120) has a heating rate of 0.5 to 5 o A 15kW electric heater with a C / min was used.
[0073] The dummy stack (200) was made of stainless steel and no electrodes were formed. The dummy stack (200) was made with dimensions of 150 mm in width x 150 mm in length x 100 mm in height. The first dummy stack (200) was placed at a point 200 mm from the gas inlet (110), and the second dummy stack (200) was placed at a point 300 mm from the gas inlet (110). The high-temperature water electrolysis stacks (300) were placed at points 500 mm, 700 mm, and 900 mm from the gas inlet (110), respectively. For the temperature measurement of each stack, a measurement error of ±1.5 o A B-type thermocouple of C was installed.
[0074] 700~800 through the gas heater (120) for initial operation of the system o Air heated to C was injected at a flow rate of 100–200 L / min. The gas temperature of the first dummy stack (200) and 50 o The temperature was raised by a difference of within C, and the rate of temperature change according to the heater's control output was ±50 relative to the target temperature.o It was measured as C. The second dummy stack (200) showed a reduced rate of temperature change compared to the dummy stack according to the control output of the heater, and ±20 based on the target temperature. o It was measured as C. Subsequently, the temperature of the gas reaching the high-temperature water electrolysis stack (300) was 750 each. o C, 725 o C, 700 o It was measured in C, confirming that the designed temperature gradient was formed. The maximum temperature difference between stacks during the initial heating process was 70 o It was C, and under normal operating conditions, 20 o It was maintained within C.
[0075] After 24 hours of continuous operation, the current density of each high-temperature water electrolysis stack (300) was measured. As a result, based on the first stack, the second stack showed 98–102% of the performance of the first stack, and the third stack showed 98–102% of the performance of the first stack, confirming that the performance uniformity of the entire system is 100% on average. The external temperature is 15 o 35 in C o Even under conditions where it changes to C, the temperature change inside the hot box (100) is ±1 o It was maintained within C.
[0076] The maximum temperature of the insulated exterior wall is 60 o It was measured as C, and at this time, the temperature difference between the inside and outside of the hot box (100) was 630~680 o C. Due to the formation of a stepwise temperature gradient through the dummy stack (200), the thermal stress applied to the high-temperature water electrolysis stack (300) was reduced by 8%.
[0077] Although various aspects of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and it will be obvious to those skilled in the art that various modifications and variations are possible within the scope of the technical concept of the present invention as described in the claims.
Claims
1. As a hot box for a high-temperature water electrolysis system to ensure the thermal stability of a high-temperature water electrolysis stack: It includes a gas inlet, a dummy stack and a high-temperature water electrolysis stack disposed inside the hot box, and The above gas inlet supplies high-temperature gas heated by a gas heater into the hot box, and The difference between the temperature of the heated high-temperature gas and the temperature of the dummy stack is greater than or equal to the difference between the temperature of the dummy stack and the high-temperature water electrolysis stack, and The interior of the above hot box is 650 to 800 o Characterized by indicating the temperature of C, Hot box for high-temperature water electrolysis systems.
2. In Paragraph 1, The above dummy stack is positioned at a first distance from the above gas inlet, and The above high-temperature water electrolysis stack is characterized by being positioned at a second distance greater than the first distance from the above gas inlet. Hot box for high-temperature water electrolysis systems.
3. In Paragraph 1, The above dummy stack has a temperature gradient of 5 per hour between the dummy stack and the high-temperature water electrolysis stack. o By ensuring a change of C or less, the operating temperature of the above high-temperature water electrolysis stack is set to 650 to 800 o Characterized by maintaining as C, Hot box for high-temperature water electrolysis systems.
4. In Paragraph 1, The above hotbox is: A heat exchanger for controlling the temperature of the above-mentioned high-temperature gas; and Characterized by additionally including insulation material, Hot box for high-temperature water electrolysis systems.
5. In Paragraph 1, The above hot box additionally includes a temperature control unit, and The above dummy stack is equipped with a dummy stack temperature sensor, and The above high-temperature water electrolysis stack is equipped with a high-temperature water electrolysis stack temperature sensor, and The above temperature control unit is characterized by reducing the heating temperature of the gas heater when the temperature difference value measured by the dummy stack temperature sensor and the high-temperature water electrolysis stack temperature sensor exceeds a preset threshold value. Hot box for high-temperature water electrolysis systems.
6. In Paragraph 5, The above preset threshold is 30 to 50 o Characterized by being a temperature selected from C, Hot box for high-temperature water electrolysis systems.
7. In Paragraph 2, The above hot box includes a plurality of high-temperature water electrolysis stacks, and The plurality of high-temperature water electrolysis stacks are arranged such that their distances from the gas inlet are different from each other, and The second distance is the distance between the gas inlet and the high-temperature water electrolysis stack that is closest to the gas inlet among the plurality of high-temperature water electrolysis stacks, and The above dummy stack is positioned closer to the gas inlet than the high-temperature water electrolysis stack located closest to the gas inlet among the plurality of high-temperature water electrolysis stacks. Hot box for high-temperature water electrolysis systems.
8. In Paragraph 1, The above dummy stack and the above high-temperature water electrolysis stack are formed of the same material, but, The above dummy stack is characterized by not having electrodes formed therein. Hot box for high-temperature water electrolysis systems.
9. In Paragraph 2, The above dummy stack includes a plurality of detailed dummy stacks, and The first distance is the distance between the dummy stack closest to the gas inlet among the plurality of dummy stacks and the gas inlet, and The plurality of dummy stacks are disposed between the gas inlet and the high-temperature water electrolysis stack. Hot box for high-temperature water electrolysis systems.
10. In Paragraph 9, Characterized by the fact that the spacing between the plurality of dummy stacks is arranged equally. Hot box for high-temperature water electrolysis systems.