Closed-loop control system and method for testing high-temperature steam dew point of SOEC

Abstract

The application provides a closed-loop control system and method for SOEC test high-temperature steam dew point, and relates to the technical field of SOEC test, which comprises a water metering unit, a steam generation and superheating unit, a segmented heat tracing and conveying unit, a mixing and dilution unit, a pre-heap detection unit, a tail gas feedback unit, a reverse flow protection unit and a controller; the controller is configured to calculate steam demand, local dew point temperature corresponding to each heat tracing section, steam quality index and reverse flow risk index; when the electrolysis current instruction exceeds the maximum allowable current, the controller limits the electrolysis current rise, and at least one of the water metering flow, the steam generation power, the superheating power, the segmented heat tracing power, the mixed gas flow and the protection gas purge state is adjusted in linkage. The application converts the steam link state into the pre-authorization condition of the electrolysis current rise, changes the steam system from passive following of the electrolysis load to active constraint of the current boundary, and realizes the "gas-heat-electricity" collaborative closed-loop control.

Description

Technical Field

[0001] This invention relates to the field of SOEC testing technology, specifically to a closed-loop control system and method for SOEC testing of high-temperature steam dew point. Background Technology

[0002] Solid oxide electrolyzers (SOECs) typically electrolyze water vapor into hydrogen and oxygen at high temperatures, requiring a continuous supply of high-temperature water vapor to the fuel electrode side during testing. Existing SOEC testing systems generally include components such as water pumps, steam generators, superheaters, heated pipelines, mass flow controllers, and dew point meters, but they mostly rely on single-point temperature control, single-point dew point feedback, or fixed flow rate settings. Steam supply systems are often set by operators who then independently set the pump or steam flow rate, passively following current changes; condensation risk assessment relies solely on the pre-pile dew point or a specific temperature; there is a lack of comprehensive steam quality verification mechanisms; backflow protection relies heavily on passive structures such as check valves; steam anomalies are usually only treated as alarms, failing to provide real-time constraints on the electrolysis current; and there is a lack of effective anti-condensation strategies after shutdown.

[0003] The aforementioned existing technologies still have the following technical defects in actual high-power SOEC testing: the steam supply is disconnected from the electrolysis load, and the steam supply margin cannot be established in advance based on the electrolysis current command, target steam utilization rate, and load ramp rate; the condensation risk assessment is too simplistic and cannot identify the weakest node most prone to condensation throughout the entire path; there is a lack of a mechanism for comprehensive verification of steam quality using inlet water flow, heating power, outlet temperature, pressure, dew point response time, and exhaust gas humidity; there is a lack of proactive assessment of backflow risk based on differential pressure direction, differential pressure change rate, valve status, and liquid level signals; there is a lack of authorization relationship between steam anomalies and electrolysis current, and no real-time constraint is formed on the electrolysis current ramp rate and maximum allowable current based on the steam supply status; premature shutdown of the heating tracing or insufficient purging after shutdown can lead to residual steam condensing in the low-temperature section. Summary of the Invention

[0004] To address the problems in related technologies, this invention provides a closed-loop control system and method for SOEC testing of high-temperature steam dew point.

[0005] To achieve the above objectives, the technical solution adopted by the present invention includes:

[0006] According to a first aspect of the present invention, a closed-loop control system for SOEC testing of high-temperature steam dew point is provided, comprising a water metering unit, a steam generation and superheating unit, a segmented heat tracing and conveying unit, a mixing and dilution unit, a pre-entry detection unit, a tail gas feedback unit, a backflow protection unit, and a controller, wherein,

[0007] The segmented heat tracing and conveying unit divides the steam conveying path into multiple independent heat tracing sections, and each heat tracing section is equipped with a pipe wall temperature sensor.

[0008] The controller is configured to:

[0009] Calculate the steam demand based on the electrolysis current command and the target steam utilization rate;

[0010] Obtain the pipe wall temperature of each heat tracing section, and calculate the local dew point temperature of each heat tracing section based on the gas pressure and water vapor mole fraction of each heat tracing section. Use the difference between the pipe wall temperature of each heat tracing section and the corresponding local dew point temperature as the dew point margin of each heat tracing section, and construct a segmented dew point margin map from the dew point margins of each heat tracing section.

[0011] Steam quality indicators are calculated based on inlet water flow, heating power, steam outlet temperature, steam outlet pressure, superheat, dew point response time, and exhaust gas feedback.

[0012] Calculate backflow risk indicators based on the pressure difference, pressure difference change rate, valve status, and / or condensate level between the steam pipeline and the inlet of the SOEC measured object;

[0013] The maximum allowable current is determined based on the test plan current, the allowable current corresponding to the effective steam supply, the allowable current corresponding to the segmented dew point margin map, the allowable current corresponding to the steam quality index, and the allowable current corresponding to the backflow risk index.

[0014] When the electrolysis current command exceeds the maximum allowable current, the controller limits the electrolysis current load and adjusts at least one of the following in conjunction: water metering flow rate, steam generation power, superheating power, segmented heating power, mixed gas flow rate, and protective gas purging status.

[0015] Optionally, the steam demand is calculated as follows: Calculate, where, The inlet steam demand molar flow rate, The number of individual cells participating in electrolysis. This is an electrolysis current command. It is Faraday's constant. The target steam utilization rate; the corresponding water mass flow rate is calculated as follows: Calculate, where, The molar mass of water;

[0016] The water metering setting is then adjusted based on the test stage margin coefficient and safety margin coefficient.

[0017] Optionally, the controller is set to Calculate the first The partial pressure of water vapor in each heating section, according to Calculate the first The local dew point temperature of each heating section, and according to Calculate the first The dew point margin of each heating section, of which... For the first The mole fraction of water vapor in each heating section For the first The gas pressure in each heating section This is a preset dew point lookup table function. For the first The pipe wall temperature of each heat tracing section; the controller according to Determine the end-to-end condensation risk margin, whereby, For the first The safety dew point margin threshold for each heat tracing section is determined, and the heat tracing section that achieves the minimum value is identified as the weakest node.

[0018] Optionally, the steam quality indicators It is obtained by weighting at least three of the following: the ratio of effective steam quantity to steam demand, the ratio of actual superheat to target superheat, the ratio of actual steam pressure to target pressure, the ratio of dew point response time to allowable response time, and the deviation of exhaust gas humidity or hydrogen production consistency.

[0019] When the water meter flow rate is normal When the current is below the quality threshold, the controller will reduce the allowable current corresponding to the steam quality index and determine that a preset condition exists. The preset condition includes at least one of insufficient vaporization, scaling, blockage, and reduced heating capacity.

[0020] Optionally, the backflow risk indicator according to , The condensate level signal and valve status are determined, among which, For steam pipeline pressure, For SOEC, the inlet pressure of the measured object; when Below the positive pressure differential safety margin or When the voltage drop rate threshold is exceeded, the controller increases... and in When the protection threshold is reached, the steam shut-off valve is closed, the inert gas purge valve is opened, the bypass or condensate drain channel is opened, and the superheater and segmented heat tracing and conveying unit are kept running.

[0021] Optionally, the controller is based on a steam supply authorization index. Determine the authorization status, the It is obtained by combining the full-link condensation risk margin, the steam quality index, the backflow risk index, and the effective steam supply after normalization;

[0022] when When the current is above the first threshold, flow rate can be increased according to the test plan. Limit the upflow rate when it is between the first and second thresholds. Freezing current when it is between the second and third thresholds, when When the current is below the third threshold, reduce the current or switch to protection purging.

[0023] Optionally, after shutdown or load reduction, the controller stops or reduces the water inlet flow while maintaining the operation of the superheater and segmented heat tracing delivery unit and purging with inert gas until the required conditions are met. Furthermore, the backflow risk indicator is below the shutdown threshold, among which, This represents the lowest pipe wall temperature in the steam link. This is the residual moisture dew point temperature. For shutdown safety dew point margin.

[0024] According to a second aspect of the present invention, a closed-loop control method for SOEC testing of high-temperature steam dew point is also provided, applied to the closed-loop control system for SOEC testing of high-temperature steam dew point described in any of the technical solutions of the first aspect of the present invention, comprising the following steps:

[0025] Calculate the steam demand based on the electrolysis current command and the target steam utilization rate;

[0026] The steam transport path is divided into multiple independent heat tracing sections. The pipe wall temperature, gas pressure and water vapor mole fraction of each heat tracing section are obtained. The local dew point temperature of each heat tracing section is calculated. The difference between the pipe wall temperature and the corresponding local dew point temperature of each heat tracing section is used as the dew point margin of each heat tracing section to construct a segmented dew point margin map.

[0027] Steam quality indicators are calculated by weighting at least three of the following: the ratio of effective steam quantity to steam demand, the ratio of actual superheat to target superheat, the ratio of actual steam pressure to target pressure, the ratio of dew point response time to allowable response time, and the consistency deviation between the exhaust gas-side reverse-engineered steam utilization rate and the current-metered steam utilization rate.

[0028] Calculate backflow risk indicators based on the pressure difference, pressure difference change rate, valve status, and / or condensate level between the steam pipeline and the inlet of the SOEC measured object;

[0029] A steam supply authorization index is generated based on the steam demand, the segmented dew point margin map, the steam quality index, and the backflow risk index. The maximum allowable current is determined based on the test plan current, the allowable current corresponding to the effective steam supply, the allowable current corresponding to the segmented dew point margin map, the allowable current corresponding to the steam quality index, and the allowable current corresponding to the backflow risk index.

[0030] When the electrolysis current command exceeds the maximum allowable current, limit the DC power supply command and / or perform at least one of the following actions: limit current increase, freeze current, reduce current, or switch to protective gas purging.

[0031] Optionally, the method further includes determining the reliability of the dew point sensor based on the consistency deviation between the measured dew point before entering the reactor, the calculated dew point obtained from the partial pressure of water vapor, and the equivalent dew point of the exhaust gas obtained by back-inferring from the exhaust gas humidity, hydrogen production, or condensate volume.

[0032] When the consistency deviation exceeds the reliability threshold, the weight of the corresponding sensor is reduced, the maximum allowable current is calculated using a conservative dew point margin, and a sensor verification or maintenance prompt is output.

[0033] According to a third aspect of the present invention, a computer-readable storage medium is also provided, on which a computer program is stored, which, when executed by a processor, is capable of implementing the steps of the closed-loop control method for SOEC testing of high-temperature steam dew point as described in any of the technical solutions of the second aspect of the present invention.

[0034] Beneficial effects:

[0035] 1. First, this invention enables dynamic quantitative linkage between steam supply and electrolysis load, avoiding reactant supply and demand imbalance. Specifically, this invention calculates steam demand based on electrolysis current command and target steam utilization rate, and further introduces a test phase margin coefficient and a safety margin coefficient to correct the water metering setting. This establishes a direct quantitative linkage between steam supply and electrolysis current. Thus, steam supply is no longer a manually set value independent of electrolysis current, but a feedforward control quantity that dynamically adjusts according to current command and establishes a margin in advance. This effectively avoids the risk of transient reactant imbalance and localized drying and degradation of the reactor stack caused by the disconnect between steam supply and electrolysis load.

[0036] Secondly, this invention enables distributed sensing of condensation risk across the entire supply chain and precise location of weak points, eliminating hidden condensation hazards. Specifically, this invention divides the steam transport path into multiple independent heat tracing sections and equips each section with a pipe wall temperature sensor. It calculates the local dew point temperature of each section based on the gas pressure and water vapor mole fraction, using the difference between the pipe wall temperature and the local dew point temperature as the dew point margin for each section. This constructs a segmented dew point margin map covering the entire path, and on this basis, an optimization algorithm automatically identifies the weakest node with the smallest dew point margin in the entire supply chain. This invention breaks through the limitations of traditional single-point temperature measurement, enabling the system to simultaneously sense the condensation risk status of all critical nodes through which the steam flows and accurately locate the most dangerous local position. This provides a clear target for directional heat tracing compensation and current limiting protection, fundamentally eliminating the safety hazards of hidden condensation at non-monitoring points.

[0037] Third, this invention enables multi-source parameter fusion and self-verification of steam quality, accurately identifying abnormal states such as insufficient effective steam quantity. Specifically, this invention calculates steam quality indicators by weighting at least three of the following: the ratio of effective steam quantity to steam demand; the ratio of actual superheat to target superheat; the ratio of actual steam pressure to target pressure; the ratio of dew point response time to allowable response time; and the consistency deviation between the exhaust gas-side back-calculated steam utilization rate and the current-metered steam utilization rate. This allows the system to no longer equate the influent flow rate solely with the effective steam quantity, but instead to cross-verify the true state of the steam from multiple perspectives, including the effective steam supply ratio, the degree of deviation in thermodynamic state, and the consistency of exhaust gas-side feedback. Thus, when the influent flow rate appears normal but the steam generator experiences scaling, blockage, or heating power degradation, the system can promptly identify abnormal states such as insufficient vaporization or decreased steam quality through the weighted results of multi-parameter fusion and lower the current boundary, preventing incompletely vaporized wet steam or entrained droplets from entering the high-temperature fuel cell stack.

[0038] Fourth, this invention enables dynamic trend prediction and proactive sequential protection against backflow risk, improving safety under unsteady conditions. Specifically, this invention integrates the pressure difference, pressure difference change rate, condensate level signal, and valve status between the steam pipeline and the SOEC measured object inlet into the calculation of backflow risk indicators. In particular, it introduces the pressure difference change rate, a key parameter reflecting the risk evolution trend, enabling the system to detect the risk increase trend before pressure reversal occurs. When the backflow risk indicator reaches the protection threshold, it sequentially executes sequential protection actions: closing the steam shut-off valve, opening the inert gas purge valve, opening the bypass or condensate drain channel, and maintaining the operation of the superheater and segmented heat tracing. In this way, it overcomes the shortcomings of traditional passive protection structures such as check valves, which can only block backflow after it occurs but cannot predict or proactively intervene in advance, effectively improving the safety of the steam link under unsteady conditions such as shutdown, load reduction, and purge switching.

[0039] Fifth, this invention makes the steam link status a multi-dimensional pre-authorization condition for electrolysis current load increase, realizing "gas-heat-electricity" coordinated closed-loop control. Specifically, this invention combines the normalized full-link condensation risk margin, steam quality index, backflow risk index, and effective steam supply to form a steam supply authorization index. The maximum allowable current is determined by taking the minimum value of the test plan current, the allowable current corresponding to the effective steam supply, the allowable current corresponding to the segmented dew point margin map, the allowable current corresponding to the steam quality index, and the allowable current corresponding to the backflow risk index. This integrates all dimensions of the steam link's physical state (including whether the supply is sufficient, whether there is a condensation risk along the entire path, whether the steam quality is reliable, and whether the backflow risk is controllable) into the current decision chain, forming a joint constraint on electrolysis current load increase. This overcomes the deficiency in existing technologies where steam anomalies are only alarm items and do not participate in current control decisions, transforming the high-temperature steam link from a passive follower of the electrolysis load into a pre-authorization and real-time constraint for electrolysis current load increase.

[0040] Sixth, this invention enables a graded and differentiated over-limit response strategy and shutdown anti-condensation protection, ensuring testing continuity and equipment safety. Specifically, this invention implements differentiated control actions according to different threshold ranges of the steam supply authorization index, such as allowing flow increase, limiting the flow rate, freezing current, reducing current, or switching to protective gas purging. This upgrades the current limiting strategy from a simple "up / down" on / off mode to a multi-level, progressive, and refined management, maintaining testing continuity as much as possible while ensuring safety. Simultaneously, after shutdown or load reduction, by stopping or reducing the inlet water flow, maintaining the superheater and segmented heat tracing operation, and purging with inert gas until the lowest pipe wall temperature is higher than the residual moisture dew point temperature plus the shutdown safety margin and the backflow risk is completely eliminated, the heat tracing can be shut off. This effectively avoids the safety hazard of residual moisture condensing into water plugs in cold pipelines.

[0041] Seventh, this invention enables triple-redundant cross-validation of dew point sensor reliability, improving system fault tolerance and reliability. Specifically, this invention uses the consistency deviation among three parameters—the measured dew point before reactor insertion, the calculated dew point obtained from water vapor partial pressure, and the equivalent dew point of the exhaust gas obtained by back-calculating from exhaust gas humidity, hydrogen production, or condensate volume—as the basis for judging sensor reliability. When the consistency deviation exceeds a reliability threshold, the weight of abnormal sensors is reduced, a conservative dew point margin is used to calculate the maximum allowable current, and a verification prompt is output, establishing a triple-redundant dew point information cross-validation mechanism. This allows the system to automatically degrade to using conservative parameters instead of relying on erroneous measurements when a single sensor drifts or fails, effectively improving the fault tolerance and reliability of the entire closed-loop control system.

[0042] 2. Other beneficial effects or advantages of the present invention will be described in detail in the specific embodiments. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] in:

[0045] Figure 1 This is a schematic diagram of the overall layout of a closed-loop control system for testing high-temperature steam dew point using SOEC, provided in an exemplary embodiment of the present invention.

[0046] Figure 2 This is a schematic diagram of a high-temperature steam link provided by an exemplary embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram of a segmented dew point margin map provided in an exemplary embodiment of the present invention;

[0048] Figure 4 This is a flowchart of a steam quality self-verification method provided by an exemplary embodiment of the present invention;

[0049] Figure 5 This is a flowchart of differential pressure control for backflow risk provided by an exemplary embodiment of the present invention;

[0050] Figure 6 This is a flowchart of the steam supply authorization current ramp-up process provided by an exemplary embodiment of the present invention;

[0051] Figure 7 This is a flowchart of the start-up and shutdown anti-condensation process provided by an exemplary embodiment of the present invention. Detailed Implementation

[0052] To facilitate a clearer and more accurate understanding of the technical solutions of this invention by those skilled in the art, the existing related technologies and their technical problems will be described in more detail below.

[0053] Solid oxide electrolyzers (SOECs) typically electrolyze water vapor into hydrogen and oxygen at high temperatures, offering advantages such as high-efficiency hydrogen production, utilization of high-temperature waste heat, suitability for high-power electrolysis testing, and verification of reversible solid oxide batteries. During SOEC testing, a continuous supply of high-temperature water vapor is required to the fuel electrode side / hydrogen electrode side, i.e., the steam inlet side as defined by the stack, and this supply must be dynamically adjusted based on the electrolysis current, target steam utilization rate, hydrogen dilution ratio, inlet pressure, exhaust gas humidity, and stack safety boundaries.

[0054] Unlike conventional gas supply, high-temperature steam in SOEC testing is not simply a matter of "having steam at all." Steam is both a reactant and a crucial parameter affecting the reducing atmosphere of the fuel cell stack, local thermal equilibrium, individual cell voltage, electrolysis efficiency, and safety margins. Insufficient steam supply can lead to localized desiccation, increased concentration polarization, abnormally high individual cell voltage, accelerated stack degradation, and even electrode damage. Unstable steam temperature, pressure, or dew point control can easily cause condensation at the steam generator outlet, mixer, heating lines, pre-injection interfaces, or during shutdown. Backflow of condensate or exhaust gas can lead to thermal shock at the stack inlet, gas path blockage, sensor contamination, valve failure, and safety risks.

[0055] Existing SOEC testing systems typically include components such as water pumps, steam generators, superheaters, heat tracing pipelines, mass flow controllers, and dew point meters. However, they mostly rely on single-point temperature control, single-point dew point feedback, or fixed flow rate settings. The following technical shortcomings still exist in actual high-power SOEC testing:

[0056] First, the steam supply is disconnected from the electrolysis load. Existing testing systems often require operators to set the pump flow rate or steam flow rate, and then independently set the electrolysis current. The steam supply system typically passively follows current changes and cannot establish a steam supply margin in advance based on electrolysis current commands, target steam utilization rates, and load ramp-up rates.

[0057] Second, the assessment of condensation risk is too simplistic. Steam piping includes multiple locations with localized low temperatures or pressure drops, such as the steam generator outlet, superheater outlet, mixer outlet, heat tracing lines, valve assemblies, and pre-entry interfaces. Measuring only the dew point before entry or a single temperature point cannot identify the weakest point most prone to condensation along the entire path.

[0058] Third, there is a lack of self-verification of steam quality. The amount of water pumped into the steam generator does not necessarily equal the effective amount of high-temperature steam entering the fuel cell stack. When the steam generator is scaled, partially blocked, or the water flow is excessively high, wet steam or insufficient vaporization may occur. The existing system lacks a mechanism for comprehensive verification using inlet water flow, heating power, outlet temperature, pressure, dew point response time, and exhaust gas humidity.

[0059] Fourth, there is a lack of proactive control over backflow risk. During shutdowns, load reductions, purging switching, or steam generator malfunctions, the steam pipeline pressure may fall below the fuel cell inlet pressure, potentially causing exhaust gas or condensate to backflow into the steam supply side. Existing systems largely rely on passive structures such as check valves, lacking proactive judgment based on differential pressure direction, differential pressure change rate, valve status, and liquid level signals.

[0060] Fifth, there is a lack of authorization relationship between steam anomalies and electrolysis current. The electrolysis current for SOEC testing should only be increased under conditions of sufficient steam supply, adequate dew point margin, and controllable backflow risk. In existing systems, steam anomalies are typically only treated as alarms, without establishing real-time constraints on the electrolysis current increase rate and maximum allowable current based on steam supply status.

[0061] Sixth, insufficient anti-condensation strategies after shutdown. After water supply or shutdown, residual high-temperature moisture remains in the steam pipeline. If the heating tracing is shut off too early or purging is insufficient, the residual steam will condense in the low-temperature section, causing water plugs, sensor contamination, or inlet thermal shock during the next startup.

[0062] In view of this, the present invention provides a novel technical solution: a closed-loop control system and method for high-temperature steam dew point in SOEC testing. The technical concept of this invention lies in breaking away from the traditional passive following of the electrolysis load in SOEC testing systems, and proactively incorporating the dew point safety margin, steam quality reliability, and backflow risk of the entire steam link into the electrolysis current load decision chain. Specifically, the present invention divides the steam delivery path into multiple independent heat tracing sections and constructs a segmented dew point margin map to achieve accurate perception and feedforward compensation of weak condensation nodes throughout the entire link; ensures a reliable mapping between the influent water volume and the effective steam volume through multi-parameter fusion of steam quality self-verification; achieves rapid isolation and protection under unsteady-state conditions through proactive judgment of backflow risk based on dynamic pressure difference; and finally, unifies the above multi-dimensional steam state information into a maximum allowable current boundary, transforming the high-temperature steam link from a passive follower of the electrolysis load to a pre-authorization and real-time constraint party for electrolysis current load increase, thereby realizing coordinated closed-loop control of "gas-heat-electricity" during SOEC testing.

[0063] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings.

[0064] like Figure 1 As shown, this embodiment provides a closed-loop control system for SOEC testing of high-temperature steam dew point, characterized by including a water metering unit, a steam generation and superheating unit, a segmented heat tracing and conveying unit, a mixing and dilution unit, a pre-entry detection unit, a tail gas feedback unit, a backflow protection unit, and a controller, wherein...

[0065] The segmented heat tracing and conveying unit divides the steam conveying path into multiple independent heat tracing sections, each of which is equipped with a pipe wall temperature sensor.

[0066] The controller is configured as follows:

[0067] Calculate the steam demand based on the electrolysis current command and the target steam utilization rate;

[0068] Obtain the pipe wall temperature of each heat tracing section, and calculate the local dew point temperature of each heat tracing section based on the gas pressure and water vapor mole fraction of each heat tracing section. Use the difference between the pipe wall temperature of each heat tracing section and the corresponding local dew point temperature as the dew point margin of each heat tracing section, and construct a segmented dew point margin map from the dew point margins of each heat tracing section.

[0069] Steam quality indicators are calculated based on inlet water flow, heating power, steam outlet temperature, steam outlet pressure, superheat, dew point response time, and exhaust gas feedback.

[0070] Calculate backflow risk indicators based on the pressure difference, pressure difference change rate, valve status, and / or condensate level between the steam pipeline and the inlet of the SOEC measured object;

[0071] The maximum allowable current is determined based on the test plan current, the allowable current corresponding to the effective steam supply, the allowable current corresponding to the segmented dew point margin map, the allowable current corresponding to the steam quality index, and the allowable current corresponding to the backflow risk index.

[0072] When the electrolysis current command exceeds the maximum allowable current, the controller limits the electrolysis current load and adjusts at least one of the following in conjunction: water metering flow rate, steam generation power, superheating power, segmented heating power, mixed gas flow rate, and protective gas purging status.

[0073] Through the above technical solution, firstly, this invention can achieve accurate perception of condensation risk and identification of weak points throughout the entire process. Specifically, this invention divides the steam transport path into multiple independent heat tracing sections and equips each section with a pipe wall temperature sensor. It calculates the local dew point temperature by combining the gas pressure and water vapor mole fraction of each section. The difference between the pipe wall temperature and the dew point temperature is used as the dew point margin for each section, forming a segmented dew point margin map. This allows the system to simultaneously monitor the condensation risk status of all key nodes through which the steam flows. This effectively overcomes the deficiency of traditional single-point temperature measurement schemes where hidden condensation cannot be detected, providing a data foundation for subsequent quantitative assessment and targeted compensation of condensation risk, with full-path visualization.

[0074] Secondly, this invention can establish a direct, quantitative linkage between steam supply and electrolysis load. Specifically, by calculating the steam demand based on the electrolysis current command and the target steam utilization rate, this invention ensures that the steam supply is no longer a manually set value independent of the electrolysis current, but rather a quantitative feedforward control quantity that dynamically adjusts according to the current command. This effectively avoids the transient imbalance of reactants caused by the disconnect between steam supply and electrolysis load, and also provides a supply benchmark that matches the electrolysis demand in real time for determining the subsequent maximum allowable current.

[0075] Third, this invention enables multi-source comprehensive verification of steam quality without blindly relying on the inlet water flow rate. Specifically, this invention comprehensively calculates steam quality indicators based on inlet water flow, heating power, steam outlet temperature, steam outlet pressure, superheat, dew point response time, and exhaust gas feedback. This prevents the system from directly equating the inlet water flow rate with the effective steam quantity. Instead, it cross-verifies the true state of the steam from multiple dimensions, including the input side, output side, dynamic response characteristics, and exhaust gas side. In this way, it can effectively overcome the shortcomings of insufficient vaporization due to scaling, blockage, or heating degradation in the steam generator, which cannot be detected by a single flow meter.

[0076] Fourth, this invention enables proactive and dynamic assessment of backflow risk, rather than passively relying on check valves. Specifically, this invention calculates backflow risk indicators based on the pressure difference between the steam pipeline and the SOEC inlet, the rate of change of the pressure difference, valve status, and / or condensate level. This expands backflow assessment from static pressure difference monitoring to multi-dimensional dynamic trend evaluation. Thus, the system of this invention can detect the increasing risk trend before pressure reversal occurs, overcoming the shortcomings of traditional passive structures such as check valves, which can only block backflow after it occurs but cannot predict or proactively intervene.

[0077] Fifth, this invention enables the steam link status to serve as a prerequisite authorization and real-time constraint for electrolysis current load increase. Specifically, this invention comprehensively determines the maximum allowable current by considering the test plan current, the allowable current corresponding to the effective steam supply, the allowable current corresponding to the segmented dew point margin map, the allowable current corresponding to the steam quality index, and the allowable current corresponding to the backflow risk index. This integrates all dimensions of the steam link's physical state into the current decision chain, effectively overcoming the deficiency in existing technologies where steam anomalies are merely alarm items and do not directly participate in electrolysis current control. When the electrolysis current command exceeds this maximum allowable current, the controller not only restricts current load increase but also adjusts at least one of the following: water metering flow rate, steam generation power, superheating power, segmented heating power, mixed gas flow rate, and protective gas purging status. This ensures that the system can proactively improve the steam state from the supply side to facilitate the restoration of load increase conditions when load increase is hindered, ultimately achieving the overall technical effect of "gas-heat-electricity" coordinated closed-loop control.

[0078] In one embodiment of the present invention, the steam demand can be calculated as follows: Calculate, where, The inlet steam demand molar flow rate, The number of individual cells participating in electrolysis. This is an electrolysis current command. It is Faraday's constant. The target steam utilization rate; the corresponding water mass flow rate is calculated as follows: Calculate, where, The molar mass of water is used; and the water metering setting is corrected according to the test stage margin factor and safety margin factor.

[0079] In this implementation, through the formula A quantitative relationship is established between steam demand and electrolysis current command, number of single cells, Faraday constant, and target steam utilization rate, so that steam supply has a clear electrochemical metrological basis; at the same time, a margin factor is introduced in the testing phase. (Can be set separately for startup, current ramp-up, steady state, load easing, and shutdown phases) and safety margin factor (To cover steam generation hysteresis and flow meter error) The water metering setting is corrected so that the steam demand calculation not only has a theoretical basis, but also can dynamically adjust the margin according to the test stage and establish the steam margin in advance before the flow rises, so as to avoid insufficient reactants due to hysteresis.

[0080] In one embodiment of the present invention, the controller can press Calculate the first The partial pressure of water vapor in each heating section, according to Calculate the first The local dew point temperature of each heating section, and according to Calculate the first The dew point margin of each heating section, of which... For the first The mole fraction of water vapor in each heating section For the first The gas pressure in each heating section for, For the first The pipe wall temperature of each heat tracing section; the controller is set to... Determine the end-to-end condensation risk margin, whereby, For the first The safety dew point margin threshold for each heat tracing section is determined, and the heat tracing section that achieves the minimum value is identified as the weakest node.

[0081] In this implementation, through the formula Calculate the partial pressure of water vapor in each section, by Obtain the local dew point temperature, and through Calculate the dew point margin for each section, quantifying the physical basis for judging condensation risk (the difference between pipe wall temperature and dew point temperature) in a clear mathematical form; further, through... By determining the condensation risk margin across the entire chain and automatically identifying the heat tracing section that achieves the minimum value as the weakest node, the system can accurately locate the most dangerous local position, providing a clear target for directional heat tracing compensation.

[0082] In one embodiment of the present invention, steam quality indicators It is obtained by weighting at least three of the following: the ratio of effective steam quantity to steam demand, the ratio of actual superheat to target superheat, the ratio of actual steam pressure to target pressure, the ratio of dew point response time to allowable response time, and the deviation of exhaust gas humidity or hydrogen production consistency.

[0083] When the water meter flow rate is normal When the current is below the quality threshold, the controller will reduce the allowable current corresponding to the steam quality index and determine that there is a preset condition. The preset condition includes at least one of insufficient vaporization, scaling, blockage, and reduced heating capacity.

[0084] In this embodiment, when the water metering flow rate is normal... When the current is below the quality threshold, the controller reduces the allowable current and determines whether there are preset conditions such as insufficient vaporization, scaling, blockage, or reduced heating capacity. In this way, the system can identify potential degradation in the steam generation or delivery process when the water intake appears normal, and infer the specific fault type from the multi-dimensional abnormal patterns.

[0085] In one embodiment of the present invention, the backflow risk indicator according to , The condensate level signal and valve status are determined, among which, For steam pipeline pressure, For SOEC, the inlet pressure of the measured object; when Below the positive pressure differential safety margin or When the voltage drop rate threshold is exceeded, the controller increases... and in When the protection threshold is reached, the steam shut-off valve is closed, the inert gas purge valve is opened, the bypass or condensate drain channel is opened, and the superheater and segmented heat tracing and conveying unit are kept running.

[0086] In this implementation, the backflow risk indicator according to , The condensate level signal and valve status are used to determine the dynamic pressure difference and its rate of change as the core judgment criteria; and, when Below the positive pressure differential safety margin or Increase when the voltage drop rate exceeds the threshold When the protection threshold is reached, the system sequentially performs the following protective actions: closing the steam shut-off valve, opening the inert gas purge valve, opening the bypass or condensate drain channel, and maintaining the operation of the superheater and segmented heat tracing. In this way, the system of the present invention can actively isolate and protect the steam link with a clear safety sequence when the risk of backflow increases.

[0087] In one embodiment of the invention, the controller is based on a steam supply authorization index. Determine the authorization status. It is obtained by combining the normalized values ​​of the whole-chain condensation risk margin, steam quality index, backflow risk index, and effective steam supply; when When the current is above the first threshold, flow rate can be increased according to the test plan. Limit the upflow rate when it is between the first and second thresholds. Freezing current when it is between the second and third thresholds, when When the current is below the third threshold, reduce the current or switch to protection purging.

[0088] In this embodiment, the controller generates a steam supply authorization index by combining the full-chain condensation risk margin, steam quality index, backflow risk index, and effective steam supply after normalization. This unifies and quantifies the four dimensions of steam state into a single authorized indicator; and, according to... Differentiated control actions, such as allowing current increase, limiting the current increase rate, freezing the current, reducing the current, or switching protection purging, are executed in different threshold ranges (above the first threshold / between the first and second thresholds / between the second and third thresholds / below the third threshold). In this way, the constraint of the electrolysis current on the steam state can be upgraded from "on-off" to multi-level progressive fine management, avoiding overly drastic control switching caused by a single-dimensional anomaly.

[0089] It is understood that the first threshold, the second threshold, and the third threshold of the present invention can be set according to actual conditions, and the present invention does not impose specific limitations on them.

[0090] In one embodiment of the present invention, after shutdown or load reduction, the controller stops or reduces the water inlet flow while maintaining the operation of the superheater and the segmented heat tracing conveying unit and purging with inert gas until the desired conditions are met. Furthermore, the backflow risk indicator is below the shutdown threshold, among which, This represents the lowest pipe wall temperature in the steam link. This is the residual moisture dew point temperature. For shutdown safety dew point margin.

[0091] In this embodiment, after shutdown or load reduction, the controller stops or reduces the water inlet flow, maintains the superheater and segmented heat tracing operation, and purges with inert gas until full. Furthermore, the backflow risk index is lower than the shutdown threshold. This clarifies the quantitative termination condition of the shutdown anti-condensation process (the minimum pipe wall temperature is higher than the residual moisture dew point temperature plus the shutdown safety margin). This allows the system of the present invention to accurately determine that the residual steam has been completely removed before shutting off the heat tracing, avoiding the condensation of residual moisture into water plugs in the cold pipeline due to premature shutdown. At the same time, it also avoids energy waste caused by excessive purging.

[0092] According to a second aspect of the present invention, a closed-loop control method for SOEC testing of high-temperature steam dew point is also provided, applicable to the closed-loop control system for SOEC testing of high-temperature steam dew point in any of the technical solutions of the first aspect of the present invention, comprising the following steps:

[0093] Calculate the steam demand based on the electrolysis current command and the target steam utilization rate;

[0094] The steam transport path is divided into multiple independent heat tracing sections. The pipe wall temperature, gas pressure and water vapor mole fraction of each heat tracing section are obtained. The local dew point temperature of each heat tracing section is calculated. The difference between the pipe wall temperature and the corresponding local dew point temperature of each heat tracing section is used as the dew point margin of each heat tracing section to construct a segmented dew point margin map.

[0095] Steam quality indicators are calculated by weighting at least three of the following: the ratio of effective steam quantity to steam demand, the ratio of actual superheat to target superheat, the ratio of actual steam pressure to target pressure, the ratio of dew point response time to allowable response time, and the consistency deviation between the exhaust gas-side reverse-engineered steam utilization rate and the current-metered steam utilization rate.

[0096] Calculate backflow risk indicators based on the pressure difference, pressure difference change rate, valve status, and / or condensate level between the steam pipeline and the inlet of the SOEC measured object;

[0097] A steam supply authorization index is generated based on steam demand, segmented dew point margin map, steam quality index and backflow risk index. The maximum allowable current is determined based on test plan current, allowable current corresponding to effective steam supply, allowable current corresponding to segmented dew point margin map, allowable current corresponding to steam quality index and allowable current corresponding to backflow risk index.

[0098] When the electrolysis current command exceeds the maximum permissible current, limit the DC power supply command and / or perform at least one of the following actions: limit current increase, freeze current, reduce current, or switch to protective gas purging.

[0099] Through the above technical solution, firstly, the method of the present invention establishes the benchmark amount of steam supply at the beginning of execution (i.e., calculates the steam demand based on the electrolysis current command and the target steam utilization rate). In this way, the steam supply can be transformed from the traditional independent manual setting to dynamic quantitative calculation based on the electrolysis current command, providing a supply target that matches the electrolysis load in real time for all subsequent closed-loop control steps, and solving the problem of the disconnect between steam supply and electrolysis load from the source of the method process.

[0100] Second, the method of the present invention simultaneously acquires temperature and pressure data and calculates the dew point margin of each independent heat tracing section along the entire path. In this way, the method of the present invention can simultaneously grasp the condensation risk status of all key nodes through which the steam flows, rather than focusing on only a single measuring point. The constructed segmented dew point margin map can provide a data foundation for full-path visualization for subsequent quantitative assessment of condensation risk, thereby overcoming the defect of traditional single-point temperature measurement schemes where hidden condensation at non-monitoring points cannot be detected.

[0101] Third, the method of the present invention weights and fuses ratio parameters of at least three dimensions, no longer equating the influent flow rate solely with the effective steam quantity, but cross-verifying the true state of the steam from multiple angles such as the effective steam supply ratio, the degree of deviation of the thermodynamic state, and the consistency of feedback from the exhaust gas side; thus, when the influent flow rate appears normal but there is scaling, blockage, or heating degradation in the steam generation or transportation process, the method of the present invention can identify abnormal states of insufficient vaporization or decreased steam quality through the weighted results of multi-parameter fusion, providing a constraint basis for the steam reliability dimension for subsequent current boundary judgment.

[0102] Fourth, the method of the present invention incorporates multi-dimensional information such as differential pressure, differential pressure change rate, valve status, and condensate level into the criteria for judging backflow risk (especially the introduction of differential pressure change rate, a parameter reflecting the trend of risk evolution), enabling the method of the present invention to detect the risk increase trend in advance before differential pressure reversal occurs; thus, the judgment of backflow risk can be upgraded from traditional static differential pressure monitoring to dynamic trend assessment, thereby overcoming the shortcomings of relying solely on passive structures such as check valves, which cannot predict and actively intervene in advance.

[0103] Fifth, in the method of this invention, the steam state information of the three dimensions of dew point margin, steam quality, and backflow risk is first quantified with the steam demand into a unified steam supply authorization index. Then, the minimum value of the allowable current corresponding to the test plan current, effective steam supply, segmented dew point margin, steam quality, and backflow risk is taken as the maximum allowable current. In this way, the physical state of the entire steam link (including whether the supply is sufficient, whether there is a risk of condensation along the entire path, whether the steam quality is reliable, and whether the backflow risk is controllable) can be incorporated into the current decision chain to form a joint constraint. This overcomes the defect in the prior art where steam anomalies are only alarm items and do not participate in the current control decision, and realizes the pre-authorization and real-time constraint of the steam link state on the electrolysis current load increase.

[0104] Sixth, in the method of the present invention, when the current command exceeds the limit, it is not limited to a single protection action, but provides a variety of optional actions such as limiting the DC power supply command, limiting the current increase rate, freezing the current, reducing the current, and switching to protective gas purging. In this way, the method of the present invention can select differentiated response strategies according to the specific degree of abnormality in the steam state (limiting the current increase rate to only when the abnormality is slight, freezing the current when the abnormality is moderate, and reducing the current or switching to protective gas purging when the abnormality is severe), instead of performing drastic actions such as shutdown in all cases. This can ensure test safety and maintain the continuity of the test as much as possible.

[0105] In one embodiment of the present invention, the method further includes determining the reliability of the dew point sensor based on the consistency deviation between the measured dew point before stacking, the calculated dew point obtained from the partial pressure of water vapor, and the equivalent dew point of the tail gas obtained by back-inferring the tail gas humidity, hydrogen production, or condensate volume; when the consistency deviation exceeds the reliability threshold, the weight of the corresponding sensor is reduced, the maximum allowable current is calculated using a conservative dew point margin, and a sensor calibration or maintenance prompt is output.

[0106] In this way, a cross-validation mechanism with triple redundancy of dew point information can be established, enabling the system of this invention to automatically degrade to using conservative parameters instead of relying on erroneous measurements when a single sensor drifts or fails, thereby improving the fault tolerance and reliability of the entire closed-loop control system.

[0107] The technical solution of the present invention will be further described below with reference to an exemplary embodiment.

[0108] I. System Composition and Functional Description.

[0109] like Figure 1 and Figure 2 As shown, the system of the present invention may include a water metering unit, a steam generation and superheating unit, a segmented heat tracing and conveying unit, a mixing and dilution unit, a pre-entry detection unit, a tail gas feedback unit, a backflow protection unit, and a controller.

[0110] Among them, Figure 1 The invention demonstrates the core physical topology and information flow of the SOEC high-temperature steam closed-loop control system. The system of this invention is constructed by water metering, steam generation and superheating, segmented heat tracing, mixing and dilution, pre-entry detection, exhaust gas feedback, and backflow protection units, which together form the steam physical link. The underlying multi-dimensional physical state is collected by sensors and sent to the controller, which then outputs strict control intervention to the DC power supply, thereby establishing a global collaborative architecture of "gas-heat-electricity".

[0111] exist Figure 2 The image shows the complete physical flow path of steam from source water metering to pre-reactor detection. Figure 2 The document not only indicates the conventional main conveying nodes, but also highlights the physical layout of the bypass discharge, low-point condensation discharge, inert gas purging interface, and differential pressure detection unit, forming the hardware execution base for active backflow prevention and anti-condensation purging.

[0112] The specific structure and core functions of each unit are explained below.

[0113] 1. Water metering unit.

[0114] The water metering unit is used to provide measurable liquid water to the steam generation and superheating unit. Specifically, it may include a water storage container or deionized water interface, a filter, a deaerator, a metering pump, a liquid mass flow meter, a weighing verification module, an inlet water pressure sensor, an inlet water temperature sensor, a check valve, a shut-off valve, and a vent valve. In this exemplary embodiment, the water metering unit can be dual-verified using both the liquid flow meter and the weighing verification module. When the deviation between the integral value of the liquid mass flow meter and the reduction amount from the weighing module exceeds a preset threshold, the controller determines that the water metering reliability has decreased and enters a water metering verification or degraded control state. The output of the water metering unit is not directly equivalent to the effective steam quantity, but rather serves as a key input for steam quality self-verification.

[0115] 2. Steam generation and superheating unit.

[0116] The steam generation and superheating unit may include a steam generator and a superheater. The steam generator is used to vaporize metered water, and the superheater is used to maintain the steam temperature above the dew point temperature at the current pressure and a predetermined superheat margin. This unit may be equipped with a steam generator inlet temperature sensor, a steam generator outlet temperature sensor, a steam generator outlet pressure sensor, a heating power detection module, a superheater outlet temperature sensor, a superheater outlet pressure sensor, a steam outlet dew point sensor, a steam generator differential pressure sensor, and a heater current or resistance status detection module. The controller determines online whether the steam generator has insufficient vaporization, scaling, blockage, dry burning, or reduced heating capacity based on the inlet water flow, heating power, outlet temperature, outlet pressure, and dew point response time.

[0117] 3. Segmented heat tracing and conveying unit.

[0118] The segmented heat tracing delivery unit delivers superheated steam to the inlet of the SOEC (Solar Energy Regulator) test object. This unit divides the entire steam pipeline into multiple independent heat tracing sections, each independently equipped with a pipe wall temperature sensor, heat tracing power regulator, insulation structure, low-point condensation drainage structure, and temperature anomaly detection module. For example, the segments may include: a steam generator outlet section, a superheater outlet section, a steam-hydrogen or inert gas mixer inlet section, a mixer outlet section, the first section of the main delivery pipeline, the second section of the main delivery pipeline, the pre-entry valve group section, and the pre-entry interface section. The pipe wall temperature of each heat tracing section is used in real-time to calculate the segmented dew point margin map. The controller determines the priority heating location based on the heat tracing section with the lowest dew point margin, achieving precise feedforward control of the weakest local condensation risk point.

[0119] 4. Mixing and dilution unit.

[0120] The mixing and dilution unit is used to uniformly mix high-temperature steam with hydrogen, nitrogen, argon, or other inert gases. Its functions include regulating the steam partial pressure at the SOEC fuel electrode inlet, maintaining a predetermined hydrogen protection ratio, providing inert protection gas during startup and shutdown, switching to protective purging in case of steam anomalies, and stabilizing the total inlet flow rate and inlet pressure, thereby reducing the risk of localized condensation or insufficient reducing atmosphere. This unit may include a static mixer, a heated mixing chamber, or a mixing pipe section with insulation. When the mixing chamber temperature falls below the dew point margin threshold, the controller will prevent further increases in water flow or prevent the electrolysis current from increasing.

[0121] 5. Pre-entry inspection unit.

[0122] The pre-entry detection unit is located before the SOEC test object inlet (preferably in a high-temperature maintainable location near the stack inlet). This unit is used to detect the dew point, gas temperature, pressure, total flow rate, pipe wall temperature, and optionally hydrogen concentration or humidity before entering the stack. The detected values ​​are used to determine whether the steam mixture entering the stack fully meets the electrolysis test conditions.

[0123] 6. Exhaust gas feedback unit.

[0124] The exhaust gas feedback unit is located at the SOEC fuel electrode outlet or in the hydrogen-side exhaust gas treatment branch. It is used to collect exhaust gas humidity, exhaust gas dew point, exhaust gas temperature, exhaust gas pressure, exhaust gas flow rate, hydrogen production, condensate volume, and exhaust gas composition. The controller uses the exhaust gas humidity or hydrogen production to infer the actual amount of water vapor consumed and compares it with the theoretical consumption based on the electrolysis current to correct the actual steam utilization rate.

[0125] 7. Backflow protection unit.

[0126] The backflow protection unit prevents exhaust gas, condensate, or fuel cell inlet-side gas from flowing back into the steam supply line. This unit may include a steam line pressure sensor, a fuel cell inlet pressure sensor, a differential pressure sensor, a steam shut-off valve, an inert gas purge valve, a bypass valve, a condensate drain valve, a low-point level sensor, a check valve, and a safety relief line. This unit utilizes both passive protection via check valves and active protection actions triggered by the controller based on dynamic differential pressure and status data.

[0127] 8. Controller

[0128] The controller can be implemented using a PLC, industrial computer, embedded controller, or host computer software to execute the high-temperature steam dew point closed-loop control method for the equipment. The controller's input is connected to the detection signals of the aforementioned units, and its output is connected to the metering pump, heating power regulator, heat tracing power regulator, gas flow controller, various control valves, and DC power supply to achieve efficient coordinated control of gas, heat, and electricity.

[0129] In this exemplary embodiment, the core control method and mathematical logic of the present invention are as follows:

[0130] 1. Basic settings for steam demand.

[0131] The controller calculates the theoretical steam consumption based on the electrolysis stoichiometry relationship on the SOEC fuel electrode / hydrogen electrode side, and the reaction formula is as follows: The theoretical molar flow rate consumed is ,in, The number of individual cells participating in electrolysis. This is the actual electrolysis current. is Faraday's constant.

[0132] The electrolysis current command is Target steam utilization rate At that time, the molar flow rate of the inlet steam demand is The corresponding water mass flow rate is ,in, This is the molar mass of water.

[0133] Combined with the test phase margin coefficient and safety margin factor The basic setting for water metering is . It can be set separately according to the startup, current increase, steady state, load decrease and shutdown stages. Used to cover steam generation hysteresis and flow meter errors.

[0134] 2. Segmented dew point margin map.

[0135] Please see Figure 3 , Figure 3 This invention demonstrates a "local condensation risk optimization" logic that breaks through the limitations of traditional single-point temperature measurement. The system can construct a segmented dew point margin map covering the entire path by collecting temperature and pressure data of each physical segment node online and calculating water vapor partial pressure; and by using an optimization algorithm to identify the "weakest node" in the entire path in real time, thereby accurately triggering directional heat tracing compensation or flow limiting control logic.

[0136] For example, the controller defines at least two of the following locations as dew point risk nodes: steam generator outlet section, superheater outlet section, mixer inlet section, mixer outlet section, main delivery line, pre-cash valve assembly section, and pre-cash interface section.

[0137] For the Each node, the controller obtains the pipe wall temperature. Gas pressure and water vapor mole fraction And calculate the partial pressure of water vapor. Local dew point temperature Use Antoine relation, steam saturation pressure gauge, or preset dew point lookup function. get.

[0138] This function can be pre-constructed based on the thermodynamic correspondence between saturated water vapor partial pressure and dew point temperature. The controller obtains the dew point temperature at the corresponding partial pressure through the inverse function of the Antoine equation, table lookup of saturated water vapor pressure, or interpolation. .

[0139] For example, local dew point temperature It can be calculated using the inverse function of the Antoine equation:

[0140]

[0141] Therefore, when the first The partial pressure of water vapor in each heating section is: At that time, its local dew point temperature can be expressed as:

[0142]

[0143] in, For water at temperature The saturated vapor pressure is given by A, B, and C, which are empirical constants corresponding to the pressure unit and temperature range, respectively. The empirical constants can be selected according to the preset temperature range. and The same pressure unit is used. The controller can also pre-store the correspondence between water vapor partial pressure and dew point temperature as dew point lookup data, and then apply it during actual control. Obtained using linear interpolation, piecewise linear interpolation, or spline interpolation .

[0144] For example, when Located at adjacent lookup points and In between, you can press:

[0145]

[0146] The corresponding dew point temperature was calculated.

[0147] In other words, function It can be obtained either by back-calculation using the Antoine equation or by looking up the relationship between the saturated water vapor partial pressure and dew point temperature from a pre-calibrated table.

[0148] No. The dew margin of each node is A segmented dew point margin map is formed from the dew point margins of each node. The condensation risk margin index is... ,in, For the first Safety dew margin threshold for each node. This indicates that at least one node is at risk of condensation, and the node that reaches the minimum value is the weakest node at present.

[0149] 3. Steam quality self-verification.

[0150] Please see Figure 4 , Figure 4The closed-loop verification process of the actual steam condition was demonstrated. The system does not blindly trust the inlet water flow rate, but deeply integrates multi-source heterogeneous data such as inlet water flow, heating power, temperature, pressure and dew point response delay, and exhaust gas humidity / condensate feedback to calculate and output a high-confidence "steam quality index", which serves as the core basis for judging incomplete vaporization, system scaling, or heating degradation.

[0151] For example, the controller does not directly equate the influent flow rate with the effective steam flow rate, but rather bases it on the actual influent mass flow rate. Steam generator heating power outlet temperature Export pressure overheating Dew point response time before stack entry And estimate the effective steam volume based on exhaust gas humidity or hydrogen production. .

[0152] Steam quality indicators You can click:

[0153] Construct, in which, to The weights are 1, This indicates that the amplitude is normalized. This is the steam superheat setpoint or minimum allowable superheat margin, used to characterize whether the steam is in a sufficiently superheated state. This refers to the actual outlet pressure of the steam generator or superheater. This is the setpoint for the steam outlet pressure under the corresponding operating conditions. The actual response time required for the dew point or humidity to reach the target stable range before being loaded into the pile after a step change in water mass flow rate, heating power or electrolysis current; Set the system's allowed response time value. This is to determine the consistency deviation between the exhaust gas-side reverse-engineered steam utilization rate and the current-metered steam utilization rate.

[0154] When the water meter flow rate is normal When the water quality remains below the threshold, the controller prioritizes identifying problems in the steam generation or delivery process rather than simply increasing the water intake. Its control actions include increasing steam generation power, increasing superheat power, limiting the rate of change in water intake, freezing or reducing the electrolysis current, and outputting diagnostic prompts for scaling, blockage, insufficient vaporization, or decreased heating capacity.

[0155] 4. Backflow risk differential pressure control.

[0156] Please see Figure 5 , Figure 5The invention demonstrates the active defense mechanism of the system under unsteady or shutdown conditions. The controller calculates the pressure difference and rate of change of pressure between the steam pipeline and the fuel cell inlet at high frequency, and combines the current liquid level signal with the valve opening and closing status. Once the backflow risk index exceeds the limit, it immediately triggers a series of time-series protection actions such as emergency shut-off, condensate drainage, and high-flow protective gas purging.

[0157] For example, the controller collects steam pipeline pressure. and SOEC measured object inlet pressure ,calculate and its rate of change . The smaller The higher the negative value, the greater the risk of exhaust gas, condensate, or inlet-side gas flowing back into the steam pipeline.

[0158] Backflow risk indicators You can press:

[0159] Calculate, where, For positive pressure differential safety margin, To allow for the rate of pressure differential decrease, This is an indicator of abnormal condensate level. This is a valve status abnormality indicator. to For weights.

[0160] when When the warning threshold is reached, the controller limits the current increase or freezes the current; when When the protection threshold is reached, the controller closes the steam shut-off valve, opens the inert gas purge valve, bypass valve or condensate drain valve, and maintains the operation of the superheater and the segmented heat tracing and conveying unit to prevent condensate or tail gas from flowing back to the steam generation side.

[0161] 5. Steam supply authorization index and current boundary.

[0162] Please see Figure 6 , Figure 6 This demonstrates the core logic of the "reverse licensing mechanism" of this invention. The system unifies the physical constraints of four dimensions—effective steam quantity, segmented dew point margin, steam quality, and backflow risk—into a maximum permissible current boundary. This allows the current ramp-up rate and limit value of the main electrolysis test line to be authorized and constrained in real time by the steam link status.

[0163] For example, the controller will control the effective steam supply, , and Converted into a unified steam supply authorization index . The higher the value, the better the steam supply, dew point safety, quality reliability, and backflow safety.

[0164] The controller further calculates the maximum allowable current. ,in, To test the planned current, The allowable current corresponds to the effective steam supply. The allowable current corresponds to the segmented dew point margin. The allowable current corresponding to the steam quality. The allowable current corresponds to the risk of backflow. This formula makes the steam link status a prerequisite for increasing the electrolytic current load.

[0165] For example, when When the flow is allowed to be increased as planned; when Time limit upflow slope; when When the current is frozen, the steam state is restored first; when The current is reduced at the set slope; when or When the protection threshold is reached, the power supply is cut off or the inert gas protection is switched on, and a safety shutdown purging is performed. For example, , , and It can be set to 0.90, 0.75, 0.60 and 0.40 respectively, or calibrated according to the stack level, test pressure and safety policy.

[0166] 6. Dynamic correction and self-closed loop.

[0167] The controller calculates the actual steam utilization rate based on exhaust gas humidity, hydrogen production, or condensate volume. and according to and Deviation correction and steam generation power. This correction is subject to Constraints should be imposed to avoid blindly increasing water volume simply because of delayed exhaust gas feedback.

[0168] The controller also compares and calculates the dew point. Dew point measured before stacking and exhaust gas reverse push dew point Consistency deviation between .when When the confidence threshold is exceeded, the controller reduces the weight of abnormal sensors, adopts a more conservative dew point margin and maximum allowable current, and outputs a sensor verification prompt.

[0169] The control method of the present invention will be described below with reference to an exemplary method.

[0170] like Figure 7As shown in this exemplary embodiment, the overall and phased flow of the method of the present invention can be as follows:

[0171] 1. Overall control process.

[0172] Step S1: Obtain the SOEC test object level parameters, rated current, target steam utilization rate and safety threshold.

[0173] Step S2: Calculate the basic setting of steam demand corresponding to the current.

[0174] Step S3: Start the water metering, steam generation, segmented heat tracing and mixing / dilution units in sequence.

[0175] Step S4: Collect the temperature and pressure of each heating section in real time and establish a segmented dew point margin map.

[0176] Step S5: Calculate steam quality indicators online based on multi-source data .

[0177] Step S6: Calculate backflow risk indicators based on online differential pressure and liquid level signals. .

[0178] Step S7: Calculate the steam supply authorization index and maximum allowable current .

[0179] Step S8: Adjust the current ramp-up rate according to the authorized index level, or perform freeze, current reduction and protection purging.

[0180] Step S9: Utilize tail gas side feedback data to dynamically self-correct the actual steam utilization rate and water metering input settings.

[0181] Step S10: In the event of a fault or normal shutdown, the anti-condensation purging process after shutdown shall be forcibly executed until the residual steam is completely removed.

[0182] exist Figure 7 The test equipment demonstrates the control sequence at the beginning and end of two highly susceptible stages to thermophysical disasters. It covers the entire lifecycle protection process, from startup preheating, establishing bottom steam, releasing upflow authorization, to shutting off water and reducing load, forced inert gas purging, and continuous residual dew point determination, ensuring that residual moisture in the pipeline is completely removed.

[0183] 2. Start-up phase control process.

[0184] First, inert gas purging is initiated and it is confirmed that there is no reverse pressure difference between the steam line and the stack inlet. Then, the segmented heating lines are started and the temperature is gradually increased to the start-up preheating temperature. Next, the steam generator and superheater are started to establish initial superheated steam under low water inlet flow and generate segmented dew point margin maps, confirming that the dew point margin of all nodes is greater than the start-up threshold. Finally, hydrogen is introduced to mix and establish an inlet reducing atmosphere. After the pre-stack conditions are completely stable, the authorization is released to enter the low-current pre-electrolysis stage.

[0185] 3. Control process during the flow ramp-up phase.

[0186] The system increases the water metering setpoint, steam generation power, and power of each heating section in advance based on the target electrolysis current slope; at the same time, it calculates the steam supply authorization index at high frequency. and maximum allowable current .

[0187] like The current boost condition is met and the current command is not higher than If so, the current can be increased normally;

[0188] like If the load ramp approaches the lower limit, reduce the load ramp rate.

[0189] like If the current falls below the freeze or descent threshold, the current command will be forcibly intercepted, suspending the current increase or forcibly reducing the current.

[0190] 4. Steady-state and abnormal handling control process.

[0191] Under steady-state conditions, the weakest heat tracing section is continuously identified, and water metering is fine-tuned using exhaust gas feedback.

[0192] When it is found that the dew point margin of a single heat tracing section is insufficient, the heat tracing power of that section should be increased precisely and preferentially.

[0193] If multiple stages are insufficient, increase the superheating power and limit the rate of increase in water intake;

[0194] If the dew point margin is too low or the steam quality is abnormal before entering the reactor, freeze the current and adjust the generating power.

[0195] If the risk of backflow increases, immediately close the steam shut-off valve and activate the inert gas high-flow purging, bypass discharge, and active flow reduction protection.

[0196] 5. Shutdown phase control process.

[0197] At the end of the test, the current decreased at the set slope, and the system simultaneously reduced the influent water flow while maintaining efficient operation of the superheater and each heat tracing section. After the current returned to zero, the influent water stopped, the shut-off valve activated to isolate the fuel cell stack, and a large flow of inert gas was introduced to perform anti-condensation purging, pushing residual high-temperature moisture out of the pipeline, and low-point condensate drainage was initiated. The controller continued to monitor until the lowest pipe wall temperature met the residual dew point margin requirement. And after the risk of backflow is completely eliminated, among which, This represents the lowest pipe wall temperature in the steam link. This is the residual moisture dew point temperature. To ensure a safe dew point margin during shutdown, the heat tracing and overheating power supplies can be shut off in stages.

[0198] The present invention will be further described below with reference to several typical exemplary embodiments.

[0199] Exemplary Example 1: Steady-state electrolysis test of SOEC stack.

[0200] In this exemplary embodiment, the object under test is an SOEC fuel cell stack, and a constant current electrolysis test is performed at a set temperature and pressure.

[0201] The controller reads the number of single batteries, target current, and target steam utilization rate, and starts water metering, steam generation, and segmented heat tracing.

[0202] The system discretizes the entire delivery link into multiple nodes and forms a segmented dew margin map.

[0203] During testing, if the dew point margins at the superheater outlet and mixer outlet are good, but the tube wall temperature of the valve section before reactor entry decreases due to localized convective heat dissipation, resulting in a lower dew point margin... The power was too low, so the controller accurately identified it as the weakest point and, without changing the power of other sections, autonomously and directionally increased the heat tracing power of the valve group section before the reactor, thus eliminating the risk of local condensation.

[0204] Exemplary Example 2: Protection control for steam response hysteresis during the upflow process.

[0205] In this exemplary embodiment, high-power SOEC stack testing requires performing a stepped current ramp-up from low load to rated load.

[0206] After receiving the current command, the controller theoretically calculates the steam base setpoint and feeds forward the water inflow and heat exchange power. However, due to the inherent physical thermal inertia inside the steam generator, the generation and delivery of effective steam produce a certain transient response lag, causing the measured dew point before being fed into the reactor core to fail to keep up synchronously for a short period of time.

[0207] At this point, the controller calculates the steam supply authorization index. The current fell into the restricted range. The system immediately intervened, forcibly reducing the current electrolytic current ramp-up rate, limiting it to stand still, and simultaneously increasing the superheater power. Only when the pre-load dew point margin was fully restored did the system release the restrictions, allowing the current to continue to rise to the target value, effectively avoiding localized drying and degradation of the reactor stack due to insufficient reactant transients.

[0208] Exemplary Example 3: Segmented self-optimization processing for localized heat tracing cable faults.

[0209] During the long-cycle steady-state electrolysis process of SOEC, a minor electrical fault suddenly occurred in the heat tracing cable between the mixer outlet and the first section of the main delivery pipeline, causing an unexpected drop in the wall temperature of that specific section.

[0210] At this point, the total dew point sensor readings and overall temperature before the reactor were not significantly fluctuating. However, the controller's segmented dew point margin map, through high-frequency updates, accurately captured the condensation risk margin index at that node. The water level was approaching a critical safety threshold. The controller immediately identified this section as the most vulnerable high-risk node, issued a maintenance alert, and automatically activated the backup heat tracing circuit for heat compensation, while temporarily limiting fluctuations in the influent flow. Thanks to the timely intervention, the dew point margin of this section quickly recovered to the safe window, and the entire steady-state test was maintained safely without interruption.

[0211] Exemplary Example 4: Abnormal Steam Quality and Steam Generator Health Diagnosis.

[0212] During the long-term SOEC durability test, the inlet pump flow rate and liquid flow meter data fed back by the water metering unit were completely normal. However, the steam quality self-calibration module of the controller detected an abnormally slow drop in the outlet temperature of the steam generator. Furthermore, during system adjustment, the response time for the measured dew point to reach the set range was... The steam pressure difference across the steam generator showed an upward trend, with a significant extension. The algorithm model comprehensively judged the steam quality indicators. The temperature remained below the warning threshold. Based on this, the controller inferred that scaling or heat exchange degradation had occurred inside the steam generator. It then increased the steam generation power for forced heat exchange compensation and directly adjusted the power control boundary, freezing the electrolytic current load limit of the test main line and issuing a maintenance prompt to prevent incompletely vaporized wet steam or entrained droplets from directly impacting the high-temperature fuel cell stack.

[0213] Exemplary Example 5: Backflow and condensation protection during shutdown.

[0214] After the test, the system entered the load reduction and shutdown procedure. The DC power supply steadily reduced the electrolysis current according to the preset slope, and the controller synchronously and proportionally reduced the inlet water flow rate, while maintaining the superheater and segmented heat tracing pipelines at the specified high temperature. When the current dropped to the preset safe minimum current, the power supply shut down, and the system completely stopped water intake. At this time, due to local heat flow changes, the pressure at the inlet side of the fuel cell stack experienced a slight instantaneous rebound, resulting in a change in the differential pressure rate. Turning negative, backflow risk indicator Instantaneous over-limit. The controller immediately activated the steam shut-off valve of the backflow protection unit to physically isolate the fuel cell inlet; simultaneously, it opened a high-flow-rate nitrogen purge valve to forcibly expel residual high-temperature moisture in the pipeline through the bypass valve and condensate drain valve, and extended the power supply time for each section of the heat tracing. Only after the residual dew point index dropped to the safe boundary of room temperature and the positive pressure differential recovered did the controller sequentially shut off the heat tracing power supply, completely eliminating the safety risk of residual moisture condensing into water plugs in the cold pipeline.

[0215] According to a third aspect of the present invention, a computer-readable storage medium is also provided, on which a computer program is stored, wherein when executed by a processor, the computer program is capable of implementing the steps of the closed-loop control method for SOEC testing of high-temperature steam dew point in any of the technical solutions of the first aspect of the present invention.

[0216] In this embodiment, the computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), a register, a hard disk, an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof, or any other form of computer-readable storage medium known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium may also be a component of the processor. The processor and the storage medium may reside in an application-specific integrated circuit (ASIC). In embodiments of the present invention, a computer-readable storage medium may be any tangible medium that contains or stores a program that may be used by or in conjunction with an instruction execution system, apparatus, or device.

[0217] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A closed-loop control system for SOEC testing of high-temperature steam dew point, characterized in that, It includes a water metering unit, a steam generation and superheating unit, a segmented heat tracing and conveying unit, a mixing and dilution unit, a pre-loading detection unit, a tail gas feedback unit, a backflow protection unit, and a controller. The segmented heat tracing and conveying unit divides the steam conveying path into multiple independent heat tracing sections, and each heat tracing section is equipped with a pipe wall temperature sensor. The controller is configured to: Calculate the steam demand based on the electrolysis current command and the target steam utilization rate; Obtain the pipe wall temperature of each heat tracing section, and calculate the local dew point temperature of each heat tracing section based on the gas pressure and water vapor mole fraction of each heat tracing section. Use the difference between the pipe wall temperature of each heat tracing section and the corresponding local dew point temperature as the dew point margin of each heat tracing section, and construct a segmented dew point margin map from the dew point margins of each heat tracing section. Steam quality indicators are calculated based on inlet water flow, heating power, steam outlet temperature, steam outlet pressure, superheat, dew point response time, and exhaust gas feedback. Calculate backflow risk indicators based on the pressure difference, pressure difference change rate, valve status, and / or condensate level between the steam pipeline and the inlet of the SOEC measured object; The maximum allowable current is determined based on the test plan current, the allowable current corresponding to the effective steam supply, the allowable current corresponding to the segmented dew point margin map, the allowable current corresponding to the steam quality index, and the allowable current corresponding to the backflow risk index. When the electrolysis current command exceeds the maximum allowable current, the controller limits the electrolysis current load and adjusts at least one of the following in conjunction: water metering flow rate, steam generation power, superheating power, segmented heating power, mixed gas flow rate, and protective gas purging status. The controller is as follows Calculate the first The partial pressure of water vapor in each heating section, according to Calculate the first The local dew point temperature of each heating section, and according to Calculate the first The dew point margin of each heating section, among which... For the first The mole fraction of water vapor in each heating section For the first The gas pressure in each heating section This is a preset dew point lookup table function. For the first The pipe wall temperature of each heat tracing section; the controller according to Determine the end-to-end condensation risk margin, whereby, For the first The safety dew point margin threshold for each heat tracing section is determined, and the heat tracing section that achieves the minimum value is identified as the weakest node.

2. The closed-loop control system for SOEC testing of high-temperature steam dew point according to claim 1, characterized in that, The steam demand is calculated according to Calculate, where, The inlet steam demand molar flow rate, The number of individual cells participating in electrolysis. This is an electrolysis current command. It is Faraday's constant. The target steam utilization rate; the corresponding water mass flow rate is calculated as follows: Calculate, where, The molar mass of water; The water metering setting is then adjusted based on the test stage margin coefficient and safety margin coefficient.

3. The closed-loop control system for SOEC testing of high-temperature steam dew point according to claim 1, characterized in that, The steam quality index It is obtained by weighting at least three of the following: the ratio of effective steam quantity to steam demand, the ratio of actual superheat to target superheat, the ratio of actual steam pressure to target pressure, the ratio of dew point response time to allowable response time, and the deviation of exhaust gas humidity or hydrogen production consistency. When the water meter flow rate is normal When the current is below the quality threshold, the controller will reduce the allowable current corresponding to the steam quality index and determine that a preset condition exists. The preset condition includes at least one of insufficient vaporization, scaling, blockage, and reduced heating capacity.

4. The closed-loop control system for SOEC testing of high-temperature steam dew point according to claim 1, characterized in that, The backflow risk indicators according to , The condensate level signal and valve status are determined, among which, For steam pipeline pressure, For SOEC, the inlet pressure of the measured object; when Below the positive pressure differential safety margin or When the voltage drop rate threshold is exceeded, the controller increases... and in When the protection threshold is reached, the steam shut-off valve is closed, the inert gas purge valve is opened, the bypass or condensate drain channel is opened, and the superheater and segmented heat tracing and conveying unit are kept running.

5. The closed-loop control system for SOEC testing of high-temperature steam dew point according to claim 1, characterized in that, The controller is based on the steam supply authorization index. Determine the authorization status, the It is obtained by combining the full-link condensation risk margin, the steam quality index, the backflow risk index, and the effective steam supply after normalization; when When the current is above the first threshold, flow rate can be increased according to the test plan. Limit the upflow rate when it is between the first and second thresholds. Freezing current when it is between the second and third thresholds, when When the current is below the third threshold, reduce the current or switch to protection purging.

6. The closed-loop control system for SOEC testing of high-temperature steam dew point according to claim 1, characterized in that, After shutdown or load reduction, the controller stops or reduces the water inlet flow while maintaining the operation of the superheater and segmented heat tracing delivery unit and purging with inert gas until the required conditions are met. Furthermore, the backflow risk indicator is below the shutdown threshold, among which, This represents the lowest pipe wall temperature in the steam link. This is the residual moisture dew point temperature. For shutdown safety dew point margin.

7. A closed-loop control method for SOEC testing of high-temperature steam dew point, characterized in that, A closed-loop control system for testing high-temperature steam dew point using SOEC according to any one of claims 1-6, comprising the following steps: Calculate the steam demand based on the electrolysis current command and the target steam utilization rate; The steam transport path is divided into multiple independent heat tracing sections. The pipe wall temperature, gas pressure and water vapor mole fraction of each heat tracing section are obtained. The local dew point temperature of each heat tracing section is calculated. The difference between the pipe wall temperature and the corresponding local dew point temperature of each heat tracing section is used as the dew point margin of each heat tracing section to construct a segmented dew point margin map. Steam quality indicators are calculated by weighting at least three of the following: the ratio of effective steam quantity to steam demand, the ratio of actual superheat to target superheat, the ratio of actual steam pressure to target pressure, the ratio of dew point response time to allowable response time, and the consistency deviation between the exhaust gas-side reverse-engineered steam utilization rate and the current-metered steam utilization rate. Calculate backflow risk indicators based on the pressure difference, pressure difference change rate, valve status, and / or condensate level between the steam pipeline and the inlet of the SOEC measured object; A steam supply authorization index is generated based on the steam demand, the segmented dew point margin map, the steam quality index, and the backflow risk index. The maximum allowable current is determined based on the test plan current, the allowable current corresponding to the effective steam supply, the allowable current corresponding to the segmented dew point margin map, the allowable current corresponding to the steam quality index, and the allowable current corresponding to the backflow risk index. When the electrolysis current command exceeds the maximum allowable current, limit the DC power supply command and / or perform at least one of the following actions: limit current increase, freeze current, reduce current, or switch to protective gas purging.

8. The closed-loop control method for SOEC testing of high-temperature steam dew point according to claim 7, characterized in that, The method also includes determining the reliability of the dew point sensor based on the consistency deviation between the measured dew point before entering the reactor, the calculated dew point obtained from the partial pressure of water vapor, and the equivalent dew point of the tail gas obtained by back-inferring the tail gas humidity, hydrogen production, or condensate volume. When the consistency deviation exceeds the reliability threshold, the weight of the corresponding sensor is reduced, the maximum allowable current is calculated using a conservative dew point margin, and a sensor verification or maintenance prompt is output.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it can implement the steps of the closed-loop control method for SOEC testing of high-temperature steam dew point as described in claim 7 or 8.

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