A method for determining a temperature rise path for outgassing of an ultrahigh temperature inert gas circulation system

Abstract

The application discloses a heating path determination method for gas removal of an ultrahigh-temperature inert gas circulation system, and steps are as follows: establishing dynamic state variables of impurity gas in the system, system pumping capacity parameters and safety constraint conditions of refractory alloy during the gas removal process; establishing a coupling relationship between the impurity gas release rate and the system pumping capacity, and determining a main release temperature interval of the impurity gas; analyzing oxidation or oxygen permeation behaviors of the refractory alloy, determining a high-temperature sensitive temperature interval of the refractory alloy, and clarifying dynamic constraint conditions for entering the interval; and combining the main release temperature interval and the high-temperature sensitive temperature interval to determine an allowed trajectory of the system temperature changing with time during the gas removal process. The application combines the state of the impurity gas in the system and the oxidation or oxygen embrittlement risk of the refractory alloy under high-temperature conditions, realizes sufficient removal of the impurity gas in the system, avoids the impurity from entering the high-temperature interval in the high release stage, and thus reduces the risk of significant oxidation or oxygen embrittlement damage of the refractory alloy.

Description

Technical Field

[0001] This invention relates to the field of working fluid purification and material service safety control technology in ultra-high temperature inert gas circulation systems. Specifically, it relates to a method for determining the heating path for degassing in ultra-high temperature inert gas circulation systems. Background Technology

[0002] In ultra-high temperature inert gas circulation systems, refractory alloys such as molybdenum-based, tungsten-based, niobium-based, and tantalum-based alloys are often used as heating components or key load-bearing structural materials to meet the requirements of high-temperature service and structural safety. These materials possess excellent mechanical properties and thermal stability under high-temperature conditions, but they are extremely sensitive to oxygen and oxygen-containing impurity gases. Even in environments using inert gases such as helium or argon as working fluids, when the concentration of impurity gases such as oxygen and water vapor is at the ppm level, it can still cause surface oxidation of the refractory alloy, oxygen permeation at grain boundaries, and the resulting oxygen embrittlement damage, seriously affecting the service life of the material and the operational reliability of the system. Therefore, before the system is started up or enters high-temperature operating conditions, it is usually necessary to degas the inert gas circulation system to reduce the content of impurity gases within the system.

[0003] In current engineering practice, a common degassing method is to use inert gas flushing combined with vacuum evacuation at room temperature to replace and remove the original gas in the system. However, this method has significant limitations in practical applications: Firstly, inert gas circulation systems are usually complex in structure and large in volume, containing numerous metal surfaces, sealing materials, and auxiliary components. These components exhibit varying degrees of adsorption and retention of impurity gases such as oxygen, water, and carbon dioxide. At room temperature, oxygen and carbon dioxide mainly exist in a physical adsorption or weakly bound state and can be gradually reduced through inert gas flushing and vacuum evacuation. However, water, due to its stronger adsorption on the surface of system materials, is often retained in the form of multilayer adsorption or weak chemisorption. Its desorption process is highly sensitive to temperature and is extremely difficult to fully release and remove at room temperature. Therefore, relying solely on room temperature flushing and vacuum evacuation, even with extended processing times, may still leave high levels of water and other impurity gases in the system. Furthermore, water is not only difficult to remove at room temperature, but also exhibits significant oxidation and oxygen embrittlement effects on refractory alloys at high temperatures, typically exceeding the harmful effects of oxygen under equivalent partial pressure. When the system temperature is increased before impurity gases, especially water vapor, have been effectively reduced, the refractory alloy is simultaneously exposed to a coupled environment of high temperature and high impurity gases, significantly increasing the risk of surface oxidation, grain boundary oxygen permeation, and the resulting oxygen embrittlement damage.

[0004] To improve the removal of impurity gases, especially water vapor, engineering practices typically involve introducing heating during the degassing process. This allows impurities adsorbed on the system's surface and within the materials to be released under thermal excitation. However, the release of impurity gases during degassing is not instantaneous but exhibits significant dynamic changes with increasing temperature and time. During the peak release phase, the concentration of impurity gases within the system often remains high. If the system temperature is indiscriminately increased during this phase, the thermodynamic driving force and reaction rate of the reaction between the refractory alloy and residual oxygen and water vapor will simultaneously increase, potentially leading to significant oxidation or oxygen embrittlement of the refractory alloy during degassing.

[0005] In existing technologies, temperature control during the degassing process typically focuses on selecting a specific degassing temperature or an upper temperature limit, often relying on experience or conservative settings. This lacks a systematic consideration of the dynamic evolution of impurity gas release behavior and material oxidation risk with temperature and impurity state during degassing. In particular, there is a lack of a technical method that can constrain and regulate the timing and magnitude of temperature increases during degassing based on changes in the state of impurity gases within the system, thereby forming a rational heating path. This problem is especially prominent in ultra-high temperature inert gas circulation systems, and has become a key technical bottleneck restricting the safe startup, high-temperature operation, and long-term service reliability of refractory alloys.

[0006] In view of the above, this application is hereby submitted. Summary of the Invention

[0007] The existing technology has the problem that it is difficult to fully remove impurities such as water and oxygen from the system under normal temperature conditions through inert gas purging and vacuum pumping. Furthermore, heating before the impurities are fully removed can expose the refractory alloy to a high-temperature coupled environment with the impurity gases, leading to oxidation or oxygen embrittlement damage. To solve this problem, this invention provides a method for determining the heating path in a high-temperature inert gas circulation system for degassing. By combining the state of the impurity gases in the system with the risk of oxidation or oxygen embrittlement of the refractory alloy under high-temperature conditions, the method uses the change in the state of the impurity gases as the basis for controlling the degassing heating process. This allows for phased restrictions and releases during the heating process, forming a restricted degassing heating path. This ensures sufficient removal of impurities while avoiding the entry of impurities into the high-temperature range before they are fully released, thereby reducing the risk of unacceptable oxidation or oxygen embrittlement damage to the refractory alloy during degassing and improving the safety and controllability of the degassing process in the high-temperature inert gas circulation system.

[0008] This invention is achieved through the following technical solution: In a first aspect, a method for determining the heating path for degassing in an ultra-high temperature inert gas circulation system includes the following steps: Includes the following steps: S1, Establish the dynamic state variables of impurity gases in the system, the system pumping capacity parameters, and the safety constraints of refractory alloy materials during the degassing process; S2. By utilizing the dynamic characteristics of impurity gas gradually being released as the temperature rises and being released in a concentrated manner within a certain temperature range during the heating process, the coupling relationship between the impurity gas release rate and the system's pumping capacity is established to determine the main release temperature range of impurity gas during the degassing process. S3, Analyze the oxidation or oxygen permeation response behavior of refractory alloys under different impurity states and heating conditions, determine the high-temperature sensitive temperature range of refractory alloys during degassing, and clarify the dynamic constraint conditions for entering this range. S4. Combining the main release temperature range of impurity gases determined in step S2 with the high-temperature sensitive temperature range of refractory alloys determined in step S3, a multi-stage restricted heating path that satisfies the system's pumping capacity and material safety constraints is constructed, and the allowable trajectory of system temperature change over time during the degassing process is determined.

[0009] In a specific implementation, the method for step S1 is as follows: S1-1, Determine the system boundary conditions and operational capacity range of the degassing process, including the type of inert gas used in the system, the effective circulation space inside the system, the method of gas extraction, flushing or gas replacement during the degassing process, the maximum extraction capacity, effective gas replacement capacity, equivalent extraction capacity parameters that the system can achieve during the degassing process, the adjustable range of system temperature, and the allowable heating rate range. S1-2, Identify the key impurity gases or their combinations that dominate the safety of the system during the degassing process; S1-3 uses the concentration or partial pressure of key impurity gases in the inert gas in the system as a dynamic state variable that changes with time and temperature to characterize the change process of the state of impurity gases in the system from the "release-dominated stage" to the "low-level stable stage" during the degassing process. S1-4, Identify the type of refractory alloy material and establish its material safety constraints under conditions containing residual impurity gas. The safety constraints include the acceptable degree of oxidation, oxygen permeation characteristics, and performance degradation threshold of the refractory alloy during the degassing process. S1-5, define the safety control objectives that the heating path must meet during the degassing process, including: The key impurity gas levels within the system continued to decrease and entered a low-level stable state. Refractory alloys do not experience oxidation or oxygen embrittlement damage that exceeds the material safety constraints.

[0010] In a specific implementation, in steps S1-3, the parameters for determining the dynamic state variables of the key impurity gas include: The relationship between the change in impurity gas concentration per unit time, the rate of change in impurity gas concentration, the ratio between the impurity gas release rate and the system's pumping capacity, and the trend characteristics of the impurity gas concentration changing from rapid change to slow change or a stable state.

[0011] In a specific implementation, step S2 is performed as follows: S2-1, Select at least one impurity gas that is representative of the system's impurity release behavior and material safety as the control impurity gas, and use its concentration or partial pressure in the inert gas as the main state variable characterizing the system's impurity state. S2-2, Establish the dynamic correlation between the release rate of impurity gases and temperature; S2-3, Introduce the effective pumping capacity parameter of the system under the corresponding operating conditions, and compare and analyze the pumping capacity with the release rate of impurity gas to characterize the system's response capability to the release of impurity gas. S2-4, Determine the main release temperature range of impurity gas based on the ratio of impurity gas release rate to system pumping capacity; S2-5, The main release temperature range is confirmed by combining the trend of impurity gas concentration with time within the main release temperature range. S2-6, the main release temperature range is marked as a restricted heating stage during the degassing process where it is not advisable to enter the high-temperature sensitive temperature range.

[0012] In a specific implementation, step S2-4, the criterion for determining the main release temperature range of the impurity gas is: When the release rate of impurity gas is significantly greater than or close to the effective pumping capacity of the system within a certain temperature range, the instantaneous concentration of the impurity gas in the system remains at a relatively high level, but it shows a continuous downward trend over time, indicating that the release behavior of impurity gas is dominant within this temperature range. Step S2-5, the criteria for confirming the main release temperature range are: The change in impurity gas concentration per unit time is significantly greater than that at low temperatures; or The rate of change in impurity gas concentration gradually decreases over time, reflecting a transition from release-dominated to decay-dominated characteristics; or The changes in impurity gas concentration gradually shifted from drastic fluctuations to gradual changes.

[0013] In a specific implementation, step S3 is performed as follows: Step S3-1: The instantaneous concentration or partial pressure of key impurity gases in the inert gas environment where the refractory alloy is located is used as the main state variable characterizing the service environment of the material. Step S3-2: Establish the response relationship between temperature and the oxidation reaction, oxygen permeation, or related property degradation behavior of refractory alloys under different impurity gas states. Step S3-3: Determine the temperature range in which the refractory alloy exhibits significant high-temperature sensitivity to temperature changes; Step S3-4 introduces the residual impurity gas state and exposure process as dynamic constraints for entering the high-temperature sensitive temperature range. Step S3-5: Divide the high-temperature sensitive temperature range into a restricted high-temperature zone and a controllable high-temperature zone; Steps S3-6 define the high-temperature sensitive temperature range and its restricted and controllable regions as material safety constraints in the degassing and heating path design, thereby limiting the maximum allowable temperature range and entry conditions of the system under different impurity states and degassing stages.

[0014] In a specific implementation, step S3-3, the criterion for determining the high-temperature sensitive temperature range is: When the temperature is raised to a certain range, and under a given residual impurity gas state, the oxidation rate, oxygen penetration depth, mass change rate, or performance degradation rate of the refractory alloy shows a significant increasing trend with temperature, and this trend has a significant amplification effect on the exposure process, this temperature range is defined as the high-temperature sensitive temperature range of the refractory alloy. Step S3-4, the dynamic constraint condition is as follows: when the concentration or partial pressure of the key impurity gas is higher than the preset threshold, even if the system temperature is in the lower part of the high temperature sensitive temperature range, it is still restricted from entering the high temperature sensitive temperature range.

[0015] In a specific implementation, step S3-5, the restricted high temperature zone is: a temperature range that is not allowed to be entered when the concentration of impurity gases is high or the material is still in a high-risk state. The controllable high-temperature zone is the temperature range that is allowed to be entered under limited exposure conditions when the concentration of impurity gases has been significantly reduced and the material risk is within an acceptable range.

[0016] In a specific implementation, step S4 is described as follows: Step S4-1: Based on the release behavior of impurity gases and the high temperature sensitivity of materials, the degassing process is divided into multiple stages, including the initial low temperature preparation stage, the main release stage of impurity gases, the transition heating stage, and the safe high temperature stage. Step S4-2: When the system is in the main release stage of impurity gas, control the temperature rise of the system to prevent it from entering the high temperature sensitive temperature range determined in step S3. Step S4-3: Use the changing characteristics of the key impurity gas state in the system as the triggering condition for switching between multiple stages to determine whether the system can enter the transition heating stage or the safe high temperature stage from the main impurity release stage. Step S4-4: When the system meets the stage switching triggering condition of step S4-3, the system temperature is allowed to enter the high temperature sensitive temperature range determined in step S3. Step S4-5 combines the stage division of step S4-1, the heating limitation conditions of step S4-2, and the stage switching trigger conditions of step S4-3 to form a restricted heating path that meets the safety constraints during the degassing process.

[0017] In a specific implementation, the safety constraints in steps S4-5 are as follows: Impurity gases are continuously released throughout the degassing process and eventually reach a low-level stable state. The system's heating behavior never exceeds the limits allowed by the system's pumping capacity and material safety constraints; The heating path is a feasible path that meets safety constraints, rather than aiming to obtain the optimal heating rate or the shortest degassing time.

[0018] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. The present invention provides a method for determining the heating path for degassing an ultra-high temperature inert gas circulation system. By combining the state of impurity gas in the system with the risk of oxidation or oxygen embrittlement of refractory alloys under high temperature conditions, the method can achieve full removal of impurity gas in the system while avoiding the entry of impurities into the high temperature range while they are still in the high release stage, thereby reducing the risk of significant oxidation or oxygen embrittlement damage to refractory alloys. 2. The present invention provides a method for determining the heating path for degassing in an ultra-high temperature inert gas circulation system. The method uses the change in the state of impurity gas in the system as the basis for controlling the degassing heating process, and restricts and releases the heating process in stages to form a restricted degassing heating path. This not only meets the requirement of fully removing impurity gas from the system, but also avoids unacceptable oxidation or oxygen embrittlement damage to refractory alloys during the degassing process, thereby improving the safety and controllability of the degassing process in the ultra-high temperature inert gas circulation system. 3. The method for determining the heating path for degassing in an ultra-high temperature inert gas circulation system provided in this embodiment of the invention is applicable to various ultra-high temperature inert gas circulation systems that use refractory alloys as structural materials, heating components or key components, including but not limited to high temperature gas-cooled reactor systems, ultra-high temperature material test loops, high temperature thermal devices and related experimental or engineering systems. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart illustrating a method for determining the heating path in an ultra-high temperature inert gas circulation system for degassing, as provided in an embodiment of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments. The illustrative embodiments and descriptions of this invention are only used to explain this invention and are not intended to limit this invention.

[0022] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other embodiments, well-known materials or methods have not been specifically described in order to avoid obscuring the invention.

[0023] Throughout this specification, references to “an embodiment,” “an example,” or “an example” mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases “an embodiment,” “an example,” “an example,” or “an example” appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items.

[0024] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60–120 and 80–110 are listed for a specific parameter, it is understood that ranges of 60–110 and 80–120 are also expected. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1–3, 1–4, 1–5, 2–3, 2–4, and 2–5. In this application, unless otherwise stated, the numerical range "a–b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0025] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0026] Example 1 This invention provides a method for determining the heating path for degassing in an ultra-high temperature inert gas circulation system, comprising the following steps: (1) Step S1: Establishment of state variables, system capacity parameters and safety constraints for the degassing process To address the engineering characteristics of ultra-high temperature inert gas circulation systems during degassing, including the dynamic release of impurity gases, the evolution of system impurity composition over time, and the highly coupled sensitivity of refractory alloy oxidation risk to temperature, impurity state, and exposure process, a state variable system, system capability parameters, and material safety constraints are established for determining the degassing heating path. The steps include: S1-1, Determine the system boundary conditions and operational capacity range of the degassing process. Determine the degassing target and operating boundary conditions of the inert gas circulation system, including the type of inert gas used in the system (such as helium, argon, or xenon), the effective circulation space inside the system, the achievable pumping, purging, or gas replacement methods during the degassing process, as well as the maximum pumping capacity, effective gas replacement capacity, or equivalent pumping capacity parameters that the system can achieve during the degassing process. Also, clarify the adjustable range of the system temperature and the allowable heating rate range to define the operational boundaries of the degassing process.

[0027] S1-2, Identify the key impurity gases and their combinations that dominate safety during the degassing process. Identify the key impurity gas types that dominate the system safety and material service risk during the degassing process. The key impurity gases include at least O2, CO, CO2, H2, N2 and H2O. Among them, H2O can be selected as a representative control impurity gas to characterize impurity release behavior and material risk because it is difficult to remove under normal temperature conditions and has strong oxidizing activity on refractory alloys under high temperature conditions.

[0028] At the same time, the single concentration state or combination state of various impurity gases in the system are considered as potential influencing factors in the degassing process.

[0029] S1-3, Establishing a descriptive method for the state variables of impurity gases and their changing characteristics. A descriptive method for the state variables of impurity gases in the system is established, taking the concentration or partial pressure of key impurity gases in the inert gas as dynamic state variables that change with time and temperature. Furthermore, one or a combination of the following decision quantities are introduced to describe the characteristics of impurity state evolution: a, the change in the concentration of impurity gas per unit time; b, the rate of change in impurity gas concentration; c, the ratio between the release rate of impurity gases and the system's pumping capacity; d, The trend of impurity gas concentration changing from rapid change to slow change or a stable state.

[0030] The state variables and their change characteristics are used to characterize the evolution of the system impurity state from the "release-dominated stage" to the "low-level stable stage" during the degassing process.

[0031] S1-4, clarify the safety constraints and risk criteria for refractory alloy materials. Identify the types of refractory alloy materials that come into direct contact with inert gases during the degassing process, and establish material safety constraints for them under conditions containing residual impurity gases. The safety constraints include at least the acceptable degree of oxidation, oxygen permeation characteristics, or performance degradation threshold of the refractory alloy during the degassing process, and regard the material safety constraints as one of the key constraints limiting the degassing heating process.

[0032] S1-5, Define the safety control objectives for the degassing and heating path. Defining the heating path during the degassing process determines the necessary safety control objectives, which include at least the following: a. The key impurity gases in the system show a continuous decreasing trend during the degassing process and eventually enter a low-level stable state. b. The refractory alloy does not undergo oxidation or oxygen embrittlement damage exceeding the material safety constraints during the entire degassing and heating process; c. The degassing and heating path is a feasible and safe path that meets the above constraints, rather than aiming to obtain the optimal heating rate or the shortest degassing time.

[0033] Through the above steps, a basic model of the degassing process is established, with the dynamic state variables of impurity gases, system extraction capacity parameters, and material safety constraints as the core. This provides a unified parameter basis and judgment criteria for subsequent determination of the main release temperature range of impurity gases, identification of the high-temperature sensitive temperature range of refractory alloys, and determination of the restricted heating path triggered by impurity states.

[0034] (2) Step S2: Determination of the main release temperature range based on the coupling of dynamic release behavior of impurity gas and system pumping capacity To address the dynamic characteristics of impurity gases in ultra-high temperature inert gas circulation systems, which exhibit gradual release with increasing temperature and concentrated release within a certain temperature range, this paper introduces a coupling relationship between the impurity gas release rate and the system's pumping capacity to determine the main release temperature range of impurity gases during the degassing process. This provides a basis for the stage division and control of the subsequent degassing heating path. The steps include: S2-1, Determine the control impurity gas and its state variables used to determine the impurity release behavior. During the degassing process, at least one impurity gas that is representative of the system's impurity release behavior and material safety is selected as the control impurity gas, and its concentration or partial pressure in the inert gas is used as the main state variable characterizing the system's impurity state. Among them, water vapor is preferred as the control impurity gas for determining the main release temperature range because it is difficult to remove under normal temperature conditions and its release behavior is significant during the heating process.

[0035] S2-2, Establish the dynamic correlation between the release rate of impurity gases and temperature. Through theoretical analysis, empirical models, or temperature-increasing degassing experiments, the rate characteristics of the release of impurity gases from the system inner wall, pipeline surface, sealing material, and non-metallic components under different temperature conditions are obtained, and a dynamic descriptive relationship between the release rate of impurity gases and temperature is established to characterize the temperature sensitivity of the impurity gases as they transition from an adsorbed state to a removable state.

[0036] S2-3, introduce the system's pumping capacity as a constraint parameter for impurity release behavior. Based on step S2-2, the effective pumping and exhausting capacity parameters of the system under corresponding operating conditions are introduced, including pumping capacity, gas replacement capacity or equivalent pumping and exhausting capacity, and the pumping and exhausting capacity is compared and analyzed with the release rate of impurity gas to characterize the system's response to the release of impurity gas.

[0037] S2-4, Determining the main release temperature range of impurity gas based on the ratio of release rate to pumping capacity. When the release rate of impurity gas is significantly greater than or close to the effective pumping capacity of the system within a certain temperature range, the instantaneous concentration of the impurity gas in the system remains at a relatively high level, but it shows a continuous downward trend over time, indicating that the release behavior of impurity gas is dominant within this temperature range.

[0038] The temperature range that meets the above characteristics is defined as the main release temperature range of impurity gases during the degassing process.

[0039] S2-5, confirming the main release temperature range by combining the evolution trend of impurity gas concentration. Within the main release temperature range, the trend of the concentration of the control impurity gas over time is analyzed. When the concentration change exhibits one or a combination of the following characteristics, the range is confirmed as an effective main release temperature range: a. The change in impurity gas concentration per unit time is significantly greater than that at low temperatures. b. The rate of change of impurity gas concentration gradually decreases over time, reflecting the transition from release-dominated to decay-dominated characteristics. c. The change in impurity gas concentration gradually shifted from drastic fluctuations to a more gradual change.

[0040] S2-6, mark the main release temperature range of impurity gases as the restricted stage of the degassing and heating path. The main release temperature range of the impurity gas is marked as a restricted heating stage during the degassing process, in which the system should not enter the high-temperature sensitive temperature range. During this stage, the system heating behavior needs to be restricted to avoid exposing the refractory alloy to the unfavorable environment of high temperature and high impurity gas partial pressure coupling when the impurity gas is still in the concentrated release and high level stage.

[0041] S2-7, Phased output within the main release temperature range The determined main release temperature range of impurity gas is output as a phased result in the degassing and heating path design, which is used to distinguish between the high impurity release stage and the transition or safe heating stage after the impurities are significantly reduced during the degassing process.

[0042] (3) Step S3: Determination of the high-temperature sensitive temperature range of refractory alloys based on the coupling of residual impurity state-temperature-exposure process To address the high sensitivity of refractory alloys to impurity gases such as oxygen and water in inert gas environments, and the fact that their oxidation or oxygen embrittlement risk is not solely determined by temperature but is influenced by the coupled effects of temperature, the state of residual impurity gases, and the exposure process, this study analyzes the response behavior of refractory alloys under different impurity states and heating conditions to determine the high-temperature sensitive temperature range of refractory alloys during degassing and to define the dynamic constraints for entering this range. The steps include: S3-1, Determine the environmental state variables of the refractory alloy during the degassing process. During the degassing process, the instantaneous concentration or partial pressure of key impurity gases in the inert gas environment where the refractory alloy is located is used as the main state variable characterizing the service environment of the material. The state variable is taken from the main release temperature range of the impurity gases determined in step S2 and the actual or expected impurity level in its subsequent stages, and together with the system temperature and the exposure process, it serves as the input condition for material risk assessment.

[0043] S3-2, Establishing a multi-factor correlation between the oxidation or oxygen permeation risk of refractory alloys. Through thermodynamic analysis, kinetic models, existing material databases, or material exposure tests, the response relationship of refractory alloys to oxidation reactions, oxygen permeation, or related performance degradation under different impurity gas states with temperature changes is established. Furthermore, the cumulative characteristics of the risk behavior under different heating stages or exposure times are considered.

[0044] S3-3, Determine the range in which refractory alloys exhibit significant sensitivity to temperature changes. When the system temperature rises to a certain temperature range, and under a given residual impurity gas state, the oxidation rate, oxygen penetration depth, mass change rate, or performance degradation rate of the refractory alloy shows a significant increasing trend with temperature, and this trend has a significant amplification effect on the exposure process, this temperature range is defined as the high-temperature sensitive temperature range of the refractory alloy.

[0045] S3-4 introduces the residual impurity gas state and exposure process as dynamic constraints for entering the high-temperature sensitive temperature range. Based on step S3-3, the residual impurity gas state is introduced as a key constraint condition for entering the high-temperature sensitive temperature range. When the concentration or partial pressure of the key impurity gas is higher than the preset threshold, even if the system temperature is in the lower part of the high-temperature sensitive temperature range, the risk of oxidation or oxygen embrittlement of the refractory alloy is still significantly amplified. At this time, the system is restricted from entering the high-temperature sensitive temperature range. When the concentration of critical impurity gases is reduced to below the threshold and the material has not suffered significant damage during the preceding degassing stage, it is permissible to enter a safe sub-zone within the high-temperature sensitive temperature range under controlled exposure conditions.

[0046] S3-5 divides the high-temperature sensitive temperature range into a restricted area and a controllable area. Based on the residual impurity gas state and material response behavior, the high-temperature sensitive temperature range is further divided into: a. Restricted high-temperature zone: The temperature range in which entry is not permitted when the concentration of impurity gases is high or the material is in a high-risk state; b. Controllable high temperature zone: The temperature range that is allowed to be entered under limited exposure conditions when the concentration of impurity gases has been significantly reduced and the material risk is within an acceptable range.

[0047] S3-6 outputs the material safety constraints for the high-temperature sensitive temperature range as the degassing and heating path. The determined high-temperature sensitive temperature range and its division into restricted and controllable regions are used as material safety constraints in the degassing and heating path design to limit the maximum allowable temperature range and entry conditions of the system under different impurity states and degassing stages.

[0048] (4) Step S4: Method for determining multi-stage restricted heating path based on impurity state triggering Based on the main release temperature range of impurity gases determined in step S2 and the high-temperature sensitive temperature range of refractory alloys and its restricted and controllable regions determined in step S3, a multi-stage restricted heating path that satisfies system capacity constraints and material safety constraints is constructed using the dynamic evolution of the impurity gas state within the system as the triggering condition. This path is used to determine the allowable trajectory of system temperature change over time during the degassing process. The steps include: S4-1, Constructing a framework for the temperature-impurity state stage division of the degassing process. Based on the release behavior of impurity gases and the high-temperature sensitivity of materials, the degassing process can be divided into at least one or a combination of the following stages: a. Initial low-temperature preparation stage: The system temperature is at a low level, the impurity gas is mainly in the adsorbed state, and the impurity release rate is low. b. Impurity main release stage: The system temperature enters the main release temperature range of impurity gas determined in step S2, and the impurity release rate is significantly improved. c. Transitional heating stage: The concentration of impurity gases changes from rapid decay to slow change at a low level; d. Safe high temperature stage: The concentration of impurity gas is at a low and stable level, and the conditions for entering the controllable high temperature zone of the material determined in step S3 are met.

[0049] S4-2, Applying a temperature limiting condition during the main impurity release phase. When the system is in the main release stage of impurity gas, the system's heating behavior is restricted to prevent the system temperature from entering the high-temperature sensitive temperature range determined in step S3, especially its restricted high-temperature range, so that the refractory alloy is not exposed to the unfavorable environment of high temperature-high impurity coupling when the impurity gas is still in the concentrated release and high level stage.

[0050] S4-3, Establish stage switching trigger conditions based on impurity state evolution. The changing characteristics of the key impurity gas state within the system are used as the triggering condition for stage switching. When one or a combination of the following conditions are met, it is determined that the system can transition from the main impurity release stage to the transition heating stage or the safe high-temperature stage: a. Control the concentration or partial pressure of impurity gases to reduce them below a preset threshold; b. A significant decrease in the amount or rate of change of the concentration of impurity gas per unit time indicates that the release behavior has changed from a dominant state to a decay-dominated state. c. The ratio of the impurity gas release rate to the system's pumping capacity is lower than the preset level.

[0051] S4-4, after the triggering conditions are met, allows entry into the material's controllable high-temperature zone. When the system meets the stage switching triggering conditions described in step S4-3, and the refractory alloy does not suffer damage exceeding material safety constraints during the preceding degassing stage, the system temperature is allowed to enter the controllable high-temperature zone within the high-temperature sensitive temperature range determined in step S3, and the system continues to heat up or maintain operation within this zone according to the restricted conditions.

[0052] S4-5 forms a constrained heating path that satisfies multiple constraints. By combining the above-mentioned stage divisions, heating limits, and stage switching triggering conditions, a restricted heating path is formed that satisfies the following constraints during the degassing process: a. Impurity gases can be continuously released throughout the degassing process and eventually reach a low-level stable state. b. The system's heating behavior never exceeds the limits allowed by the system's pumping capacity and material safety constraints; c. The heating path is a feasible path that meets the safety constraints, rather than aiming to obtain the optimal heating rate or the shortest degassing time.

[0053] S4-6 outputs the constrained heating path as the control result of the degassing process. The determined restricted heating path is output as the control basis for the degassing process, which guides the heating behavior of the system under different impurity states and degassing stages, thereby achieving the synergistic satisfaction of sufficient removal of impurity gases and safety of refractory alloy materials.

[0054] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0055] Example 2 This embodiment uses a helium circulation degassing system employing molybdenum-based refractory alloys as the material for high-temperature heated components as an example. H2O is used as the controlled impurity gas, and O2 as an auxiliary impurity gas for monitoring. The specific application process of the heating path determination method described in this invention is explained in detail. It should be noted that the parameters, formulas, and determination processes used in this embodiment are only for illustrating the technical solution of this invention and do not constitute a limitation on the scope of protection of this invention.

[0056] The basic operating conditions of the system described in this embodiment are as follows: the working fluid is high-purity helium, and the effective circulation space of the system is 0.12 m³. 3 The degassing process employs a combination of vacuum pumping and low-flow helium flushing; the system's equivalent pumping capacity is 1.8 m³. 3 The system's allowable temperature range is from room temperature to 900 °C; the allowable heating rate range is 0.5–5 °C / min. The key heated component in the system that comes into direct contact with the gas is a molybdenum-based refractory alloy, and its acceptable material safety constraints are set as follows: during the degassing and heating process, the cumulative oxidation weight gain of the molybdenum-based refractory alloy shall not exceed 0.20 mg / cm³. 2 The equivalent oxygen penetration depth should not exceed 15 μm, and before entering the high-temperature stage, the concentration of impurity H2O should be reduced to below 10 ppm and tend to stabilize.

[0057] (1) Step S1: Establishment of process state variables, system capability parameters and material safety constraints S1-1, Determine system boundary conditions and capability parameters In this embodiment, the effective circulation space of the system is denoted as V, and V = 0.12 m. 3 The equivalent extraction capacity is denoted as Q_eff, and Q_eff = 1.8 m. 3 / h. Therefore, the equivalent pumping coefficient k per unit volume of the system is: k = Q_eff / V = ​​1.8 / 0.12 = 15 h -1 =0.25 min -1 ; This parameter characterizes the system's ability to pump out impurity gases under the ideal mixing assumption.

[0058] S1-2, identify the key impurity gas.

[0059] Based on the description in the background section of this invention regarding the difficulty of removing water vapor at room temperature and its significant harmful effects on refractory alloys at high temperatures, this embodiment selects H2O as the control impurity gas and O2 as the auxiliary impurity gas for identification. The stage switching of the degassing and heating path is mainly based on the evolution characteristics of H2O concentration.

[0060] S1-3, Establish dynamic state variables The H2O volume fraction concentration calculated from the online dew point meter at the system outlet is denoted as C_w(t,T), in ppm; the O2 volume fraction concentration measured by the online oxygen analyzer is denoted as Co(t,T), in ppm. Taking H2O as an example, under the ideal mixing approximation, its dynamic material balance relationship can be expressed as: V·dC_w / dt = G_w(T,t) - Q_eff·C_w; In the formula, G_w(T,t) represents the equivalent release rate of H2O from the surface of materials, seals, and pipeline adsorption sites within the system to the gas phase at temperature T and time t, and the unit can be uniformly converted to ppm·m 3 / h. Further, the expression for the H2O release rate can be obtained as: G_w(T,t)=V·dC_w / dt+Q_eff·C_w Define the H2O release-extraction ratio λ_w as: λ_w = G_w / (Q_eff·C_w), then we have λ_w=1+(V / (Q_eff·C_w))·dC_w / dt; When λ_w > 1, it indicates that the release of H2O within the system is still stronger than that dominated by pumping; when λ_w ≈ 1, it indicates that the system is in the main release plateau stage where release and pumping are roughly equal; when λ_w < 1, it indicates that the system has entered the decay release stage.

[0061] S1-4, Establishing safety constraints for molybdenum-based refractory alloys In this embodiment, the risk of H2O impurities to molybdenum-based refractory alloys is characterized by a ternary constraint of "temperature T - H2O concentration C_w - exposure time τ". Based on the preset process safety objectives of this embodiment, the material safety criterion function R_m is defined as: R_m=(T / T_c)·(C_w / C_c)·(τ / τ_c); Wherein, T_c, C_c, and τ_c are reference values ​​for materials entering the significant risk amplification zone. For ease of engineering assessment, this embodiment uses T_c = 500 ℃, C_c = 10 ppm, and τ_c = 2 h.

[0062] When R_m < 1, the material risk is considered to be within an acceptable range; when R_m ≥ 1, the material is considered to have entered a high-risk exposure state, and it is not allowed to continue heating or heat preservation under the current conditions.

[0063] S1-5, Define safety control objectives The control objective of this embodiment is: a. The H2O concentration continued to decrease and eventually stabilized below 10 ppm; b. Throughout the entire degassing process, the molybdenum-based refractory alloy always satisfies R_m<1; c. Based on the above conditions, determine the feasible restricted heating path.

[0064] (2) Step S2: Specific determination of the main release temperature range To determine the main H2O release temperature range, this embodiment employs a segmented heating-isothermal monitoring method. After initial evacuation and helium purging at room temperature, the system is heated to the target temperature at a rate of 2 °C / min and held at that temperature for 2 h, recording the changes in outlet H2O concentration. The measured data are shown in Table 1.

[0065] Table 1 Temperature range <![CDATA[Average concentration of H2O]]> Final concentration change rate dC_w / dt 60℃ constant temperature stage 95 ppm -8 ppm / h 120℃ constant temperature stage 180 ppm -22 ppm / h 80℃ constant temperature stage 320 ppm -48 ppm / h 240℃ constant temperature stage 410 ppm -55 ppm / h 300℃ constant temperature stage 290 ppm -60 ppm / h 360℃ constant temperature stage 120 ppm -28 ppm / h 420℃ constant temperature stage 38 ppm -10 ppm / h Substituting the above data into the formula G_w=V·dC_w / dt+Q_eff·C_w (where V=0.12 m) 3 Q_eff=1.8m 3 / h).

[0066] Taking the 240℃ constant temperature stage as an example: G_w=0.12×(-55)+1.8×410=731.4 ppm·m 3 / h; The corresponding extraction term is Q_eff·C_w = 1.8 × 410 = 738 ppm·m³ / h. Therefore: λ_w = 731.4 / 738 ≈ 0.99; Taking the 180℃ constant temperature stage as an example: G_w=0.12×(-48)+1.8×320=570.24 ppm·m 3 / h; Q_eff·C_w=576 ppm·m 3 / h; λ_w≈0.99.

[0067] Taking the 300℃ constant temperature stage as an example: G_w=0.12×(-60)+1.8×290=514.8 ppm·m 3 / h; Q_eff·C_w=522 ppm·m 3 / h; λ_w≈0.99.

[0068] It is evident that within the 180–300 °C range, the H2O concentration remains at a relatively high level, and the release rate is close to the system's pumping capacity, meeting the main release criteria described in the claims: "the release rate is significantly greater than or close to the system's effective pumping capacity, and the instantaneous concentration remains at a relatively high level, but continues to decrease over time." Therefore, this embodiment defines 180–300 °C as the main release temperature range for H2O, and 300–420 °C as the attenuation transition range after the main release.

[0069] (3) Step S3: Specific determination of the high temperature sensitive temperature range of molybdenum-based refractory alloys In this embodiment, H2O is used as the main controlling impurity, and the material risk criterion function R_m is employed to determine the high-temperature sensitive region of the molybdenum-based refractory alloy. Based on the aforementioned settings: R_m=(T / 500)·(C_w / 10)·(τ / 2) In the degassing and heating path, if the expected holding time for a certain stage is τ = 1 h, then R_m = (T / 500)·(C_w / 20). When R_m ≥ 1, this temperature-impurity combination is unacceptable.

[0070] Calculations are performed for several typical temperature conditions: When T = 400 ℃, if C_w = 40 ppm, then: R_m = (400 / 500) × (40 / 20) = 1.6; This indicates that at a H2O level of 40 ppm, 400 ℃ has entered a high-risk zone; When T = 450 ℃, and C_w = 20 ppm, then: R_m = (450 / 500) × (20 / 20) = 0.9; This indicates that 450 °C is close to the risk threshold at around 20 ppm; When T = 500 ℃, and C_w = 10 ppm, then: R_m = (500 / 500) × (10 / 20) = 0.5; This indicates that when H2O has dropped to 10 ppm and exposure time is limited, 500 ℃ is still within a controllable range; When T = 650 ℃, if C_w = 8 ppm, then: R_m = (650 / 500) × (8 / 20) = 0.52; This indicates that 650 °C can be considered a controlled high-temperature zone under low water content conditions; When T = 650 ℃, and C_w = 20 ppm, then: R_m = (650 / 500) × (20 / 20) = 1.3; This indicates that the temperature should not be increased to 650 °C under conditions of high residual H2O.

[0071] The results above show that the risk of molybdenum-based refractory alloys under the conditions of this embodiment is not solely determined by temperature, but is jointly constrained by H2O concentration and exposure time. Based on the principle of engineering conservatism, the high-temperature sensitive temperature range can be determined to be above 400 °C; where: 400–500 °C is a conditionally restricted entry zone; 500–700 °C is a controllable high-temperature zone that can only be entered when H2O has dropped below 10 ppm and the exposure time is controlled; when the H2O concentration is higher than 20 ppm, the area above 400 °C is considered a restricted high-temperature zone. Therefore, in this embodiment, the high-temperature sensitive temperature range of molybdenum-based refractory alloys is determined to be 400–700 °C, where: a. Limited high-temperature zone: when C_w>20 ppm, it is 400~700 ℃; b. Controllable high temperature zone: 500-700 ℃ when C_w≤10 ppm and no abnormal oxidation occurs in the preceding stage.

[0072] (4) Step S4: Determining the specific heating path of the restricted heating path Based on the H2O main release temperature range of 180–300 °C determined in step S2, and the high-temperature sensitive temperature range of 400–700 °C for molybdenum-based refractory alloys determined in step S3, the heating path in this embodiment follows the following principles: First, the system should not rapidly traverse the main release zone of 180–300 °C. Instead, it should heat up at a low speed and set up a constant temperature platform to ensure that H2O is fully released and extracted. Second, the system temperature must not exceed 400 ℃ before the H2O concentration is higher than 20 ppm; Third, the controlled high temperature zone above 500 ℃ can only be entered when the H2O concentration is reduced to below 10 ppm and the absolute value of the concentration change rate is not higher than 2 ppm / h.

[0073] Based on this, the restricted heating path in this embodiment is determined as follows: Phase I: Initial Cryogenic Preparation Phase The system was heated from room temperature to 120 ℃ at a rate of 3 ℃ / min; after reaching 120 ℃, it was kept at a constant temperature for 1 h to remove weakly adsorbed impurities at low temperatures.

[0074] Phase II: Pre-release phase The system was heated from 120 °C to 180 °C at a rate of 1.5 °C / min; after reaching 180 °C, it was held at that temperature for 1.5 h. During this stage, the final H2O concentration was usually still above 200 ppm, and further rapid heating was not permitted.

[0075] Phase III: Main Core Release Phase The system was heated from 180 °C to 240 °C at a rate of 1 °C / min; after reaching 240 °C, it was held at that temperature for 2 h. Based on the aforementioned calculations, the H2O release and extraction capacity were approximately equivalent during this stage, making it a typical main release platform.

[0076] Phase IV: Post-Main Release The system was heated from 240 ℃ to 300 ℃ at a rate of 1 ℃ / min; after reaching 300 ℃, it was held at that temperature for 2 h. At the end of this stage, the H2O concentration dropped to approximately 80–120 ppm, but it was still not allowed to enter the high-temperature sensitive area above 400 ℃.

[0077] Phase V: Transitional decay phase The system was heated from 300 ℃ to 360 ℃ at a rate of 1.5 ℃ / min; after reaching 360 ℃, it was held at that temperature for 1 h; then it was heated to 420 ℃ at a rate of 1 ℃ / min and held at that temperature for 1 h. The transition decay phase could only end when online monitoring met the following conditions: C_w ≤ 20 ppm and |dC_w / dt| ≤ 5 ppm / h.

[0078] Phase VI: Safe High Temperature Entry Phase When the following conditions are met: C_w≤10 ppm, |dC_w / dt|≤2 ppm / h, and C_o≤5 ppm, the system is allowed to be heated from 420 ℃ to 550 ℃ at a heating rate of 1 ℃ / min, and then held at 550 ℃ for 1 h for high-temperature deep degassing.

[0079] Phase VII: Controllable High Temperature Completion Stage After stage VI, if the H2O concentration remains stable below 10 ppm, the temperature can be increased from 550 ℃ to 650 ℃ at a rate of 0.5 ℃ / min, and held at that temperature for 0.5–1 h to complete high-temperature degassing. After that, the system can be switched to the target operating temperature or cooled down and shut down as needed.

[0080] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for determining the heating path for degassing in an ultra-high temperature inert gas circulation system, characterized in that, Includes the following steps: S1, Establish the dynamic state variables of impurity gases in the system, the system pumping capacity parameters, and the safety constraints of refractory alloy materials during the degassing process; S2. By utilizing the dynamic characteristics of impurity gas gradually being released as the temperature rises and being released in a concentrated manner within a certain temperature range during the heating process, the coupling relationship between the impurity gas release rate and the system's pumping capacity is established to determine the main release temperature range of impurity gas during the degassing process. S3, Analyze the oxidation or oxygen permeation response behavior of refractory alloys under different impurity states and heating conditions, determine the high-temperature sensitive temperature range of refractory alloys during degassing, and clarify the dynamic constraint conditions for entering this range. S4. Combining the main release temperature range of impurity gases determined in step S2 with the high-temperature sensitive temperature range of refractory alloys determined in step S3, a multi-stage restricted heating path that satisfies the system's pumping capacity and material safety constraints is constructed, and the allowable trajectory of system temperature change over time during the degassing process is determined.

2. The method for determining the heating path for degassing in an ultra-high temperature inert gas circulation system as described in claim 1, characterized in that, The specific method for step S1 is as follows: S1-1, Determine the system boundary conditions and operational capacity range of the degassing process, including the type of inert gas used in the system, the effective circulation space inside the system, the method of gas extraction, flushing or gas replacement during the degassing process, the maximum extraction capacity, effective gas replacement capacity, equivalent extraction capacity parameters that the system can achieve during the degassing process, the adjustable range of system temperature, and the allowable heating rate range. S1-2, Identify the key impurity gases or their combinations that dominate the safety of the system during the degassing process; S1-3 uses the concentration or partial pressure of key impurity gases in the inert gas in the system as a dynamic state variable that changes with time and temperature to characterize the change process of the state of impurity gases in the system from the "release-dominated stage" to the "low-level stable stage" during the degassing process. S1-4, Identify the type of refractory alloy material and establish its material safety constraints under conditions containing residual impurity gas. The safety constraints include the acceptable degree of oxidation, oxygen permeation characteristics, and performance degradation threshold of the refractory alloy during the degassing process. S1-5, define the safety control objectives that the heating path must meet during the degassing process, including: The key impurity gas levels within the system continued to decrease and entered a low-level stable state. Refractory alloys do not experience oxidation or oxygen embrittlement damage that exceeds the material safety constraints.

3. The method for determining the heating path for degassing in an ultra-high temperature inert gas circulation system as described in claim 2, characterized in that, In steps S1-3, the parameters for determining the dynamic state variables of the key impurity gas include: The relationship between the change in impurity gas concentration per unit time, the rate of change in impurity gas concentration, the ratio between the impurity gas release rate and the system's pumping capacity, and the trend characteristics of the impurity gas concentration changing from rapid change to slow change or a stable state.

4. The method for determining the heating path for degassing in an ultra-high temperature inert gas circulation system as described in claim 1, characterized in that, The specific method for step S2 is as follows: S2-1, Select at least one impurity gas that is representative of the system's impurity release behavior and material safety as the control impurity gas, and use its concentration or partial pressure in the inert gas as the main state variable characterizing the system's impurity state. S2-2, Establish the dynamic correlation between the release rate of impurity gases and temperature; S2-3, Introduce the effective pumping capacity parameter of the system under the corresponding operating conditions, and compare and analyze the pumping capacity with the release rate of impurity gas to characterize the system's response capability to the release of impurity gas; S2-4, Determine the main release temperature range of impurity gas based on the ratio of impurity gas release rate to system pumping capacity; S2-5, The main release temperature range is confirmed by combining the trend of impurity gas concentration with time within the main release temperature range. S2-6, the main release temperature range is marked as a restricted heating stage during the degassing process where it is not advisable to enter the high-temperature sensitive temperature range.

5. The method for determining the heating path for degassing in an ultra-high temperature inert gas circulation system as described in claim 4, characterized in that, Step S2-4, the criteria for determining the main release temperature range of impurity gases are: When the release rate of impurity gas is significantly greater than or close to the effective pumping capacity of the system within a certain temperature range, the instantaneous concentration of the impurity gas in the system remains at a relatively high level, but it shows a continuous downward trend over time, indicating that the release behavior of impurity gas is dominant within this temperature range. Step S2-5, the criteria for confirming the main release temperature range are: The change in impurity gas concentration per unit time is significantly greater than that at low temperatures; or The rate of change in impurity gas concentration gradually decreases over time, reflecting a transition from release-dominated to decay-dominated characteristics; or The changes in impurity gas concentration gradually shifted from drastic fluctuations to gradual changes.

6. The method for determining the heating path for degassing in an ultra-high temperature inert gas circulation system as described in claim 1, characterized in that, The specific method for step S3 is as follows: Step S3-1: The instantaneous concentration or partial pressure of key impurity gases in the inert gas environment where the refractory alloy is located is used as the main state variable characterizing the service environment of the material. Step S3-2: Establish the response relationship between temperature and the oxidation reaction, oxygen permeation, or related property degradation behavior of refractory alloys under different impurity gas states. Step S3-3: Determine the temperature range in which the refractory alloy exhibits significant high-temperature sensitivity to temperature changes; Step S3-4 introduces the residual impurity gas state and exposure process as dynamic constraints for entering the high-temperature sensitive temperature range. Step S3-5: Divide the high-temperature sensitive temperature range into a restricted high-temperature zone and a controllable high-temperature zone; Steps S3-6 define the high-temperature sensitive temperature range and its restricted and controllable regions as material safety constraints in the degassing and heating path design, thereby limiting the maximum allowable temperature range and entry conditions of the system under different impurity states and degassing stages.

7. The method for determining the heating path for degassing in an ultra-high temperature inert gas circulation system as described in claim 6, characterized in that, Step S3-3, the criteria for determining the high-temperature sensitive temperature range are as follows: When the temperature is raised to a certain range, and under a given residual impurity gas state, the oxidation rate, oxygen penetration depth, mass change rate, or performance degradation rate of the refractory alloy shows a significant increasing trend with temperature, and this trend has a significant amplification effect on the exposure process, this temperature range is defined as the high-temperature sensitive temperature range of the refractory alloy. Step S3-4, the dynamic constraint condition is as follows: when the concentration or partial pressure of the key impurity gas is higher than the preset threshold, even if the system temperature is in the lower part of the high temperature sensitive temperature range, it is still restricted from entering the high temperature sensitive temperature range.

8. The method for determining the heating path for degassing in an ultra-high temperature inert gas circulation system as described in claim 6, characterized in that, Step S3-5, the restricted high temperature zone is: the temperature range that is not allowed to be entered when the concentration of impurity gases is high or the material is still in a high-risk state; The controllable high-temperature zone is the temperature range that is allowed to be entered under limited exposure conditions when the concentration of impurity gases has been significantly reduced and the material risk is within an acceptable range.

9. The method for determining the heating path for degassing in an ultra-high temperature inert gas circulation system as described in claim 1, characterized in that, The specific method for step S4 is as follows: Step S4-1: Based on the release behavior of impurity gases and the high temperature sensitivity of materials, the degassing process is divided into multiple stages, including the initial low temperature preparation stage, the main release stage of impurity gases, the transition heating stage, and the safe high temperature stage. Step S4-2: When the system is in the main release stage of impurity gas, control the temperature rise of the system to prevent it from entering the high temperature sensitive temperature range determined in step S3. Step S4-3: Use the changing characteristics of the key impurity gas state in the system as the triggering condition for switching between multiple stages to determine whether the system can enter the transition heating stage or the safe high temperature stage from the main impurity release stage. Step S4-4: When the system meets the stage switching triggering condition of step S4-3, the system temperature is allowed to enter the high temperature sensitive temperature range determined in step S3. Step S4-5 combines the stage division of step S4-1, the heating limitation conditions of step S4-2, and the stage switching trigger conditions of step S4-3 to form a restricted heating path that meets the safety constraints during the degassing process.

10. The method for determining the heating path for degassing in an ultra-high temperature inert gas circulation system as described in claim 9, characterized in that, The specific safety constraints in step S4-5 are as follows: Impurity gases are continuously released throughout the degassing process and eventually reach a low-level stable state. The system's heating behavior never exceeds the limits allowed by the system's pumping capacity and material safety constraints; The heating path is a feasible path that meets safety constraints, rather than aiming to obtain the optimal heating rate or the shortest degassing time.

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