Dynamic pressure stabilization control method and system for a sealed plasma furnace

Abstract

The present application relates to the technical field of plasma furnace gas pressure control, and particularly relates to a dynamic pressure stabilization control method and system for a sealed plasma furnace, wherein in one aspect, the first derivative of the characteristic spectrum information of the lively metal in the furnace is taken as the basis for judging the influence of the enhanced volatilization of the lively metal on the gas pressure in the furnace, so as to achieve the purpose of adjusting the pumping rate of the pumping device in real time according to the change rate of the characteristic spectrum information, thereby realizing the active prediction and stable control of the gas pressure in the furnace; in another aspect, the present application further considers the influence of the pressure increase caused by the cracking of the raw gas on the gas pressure in the furnace, realizes the double-disturbance coupling control of the pressure increase caused by the volatilization of the lively metal and the cracking of the raw gas, adjusts the pressure increase factors from the downstream side and the upstream side in two directions, reduces the pressure disturbance caused by the superposition of the volatilization of the lively metal and the cracking of the raw gas, and improves the stability and controllability of the sealed plasma high-temperature reaction process.

Description

Technical Field

[0001] This invention relates to the field of plasma furnace pressure control technology, specifically to a dynamic pressure stabilization control method and system for a sealed plasma furnace. Background Technology

[0002] Plasma furnaces are widely used in high-temperature metallurgy, materials preparation, and gas-phase reactions. The furnace pressure is a crucial process parameter affecting the discharge state, heat and mass transfer efficiency, reaction rate, and product quality. Especially in high-temperature processing involving reactive metals such as magnesium, the materials are prone to volatilization upon heating. The volatilized metal vapors or related gaseous components can cause continuous fluctuations or even increases in furnace pressure, adversely affecting process stability and equipment safety. Therefore, real-time, precise, and stable control of the furnace pressure remains a key technical challenge in the automated operation of such equipment.

[0003] Currently, most pressure control technologies employ pressure sensors to detect actual pressure values, followed by closed-loop regulation via actuators such as vacuum pumps and regulating valves. Common control methods include PID control, segmented control, and predictive control. While these solutions can achieve general pressure regulation, they are essentially control methods based on hysteresis feedback correction of actual pressure changes, lacking the ability to proactively identify and intervene in early changes within the reaction zone. Especially in scenarios requiring continuous, quantitative, and precise adjustment of the pumping rate, relying solely on the hysteresis feedback of pressure sensors is often insufficient to promptly suppress pressure fluctuations while simultaneously ensuring process stability and safety.

[0004] Therefore, it is still necessary to propose a furnace pressure control technology that is more suitable for high-temperature volatilization scenarios of reactive metals. Summary of the Invention

[0005] The purpose of this invention is to provide a dynamic pressure stabilization control method for a closed plasma furnace, aiming to solve the problem that existing pressure feedback regulation methods lack the ability to identify and actively intervene in early changes in the reaction region, resulting in regulation lag. The specific technical solution is as follows: A dynamic pressure stabilization control method for a closed plasma furnace, wherein a gas extraction device for extracting gas from the furnace is connected downstream of the plasma furnace, and a gas supply device for supplying at least two raw material gases to the furnace is connected upstream of the plasma furnace, the control method comprising: Collection furnace Always Lively Metal Based on the characteristic spectral information, the first derivative of the characteristic spectral information is used to calculate... Always Lively Metal Increased gas volume due to enhanced volatility; according to Calculate the equivalent gas increase from cracking by assessing the degree of cracking of all crackable feed gases in the furnace at any given time. Based on the equivalent gas increase from volatilization and the equivalent gas increase from cracking, the total equivalent pressure increase trend in the furnace is calculated. based on The distribution coefficient and total equivalent pressure trend at each moment are used to calculate the equivalent adjustment of downstream side air extraction and upstream side air intake. Based on the equivalent adjustment amount of downstream side air extraction and Calculation of pressure deviation inside the furnace at any time The actual pumping rate of the pumping device is calculated based on the equivalent adjustment amount of the upstream air intake. Total air intake setting at any given time.

[0006] Preferably, the first derivative of the characteristic spectral information is multiplied by a coefficient. To obtain active metals Increased gas volume due to enhanced volatility ;in, It is the proportionality coefficient that maps the first derivative of the characteristic spectral information to the volatile equivalent gas increase.

[0007] Preferred, The equivalent gas increase caused by the cracking of all crackable feedstock gases in the furnace at all times Represented as: in, Indicates the gas cracking booster coefficient; Indicates the first The degree of cracking of a type of crackable feedstock gas; Indicates the first A type of crackable feedstock gas in The intake airflow at any given time; This represents the total number of types of crackable feedstock gases.

[0008] Preferred, the first A type of crackable feedstock gas in Fragmentation degree coefficient at time The determination method is as follows: Get The feedstock gas can be cracked at any time Inlet molar flow rate at the furnace inlet And detect the crackable raw material gas at the furnace outlet. molar flow rate of pyrolysis gas products Then the raw material gas can be cracked. exist Fragmentation degree coefficient at time Represented as: in, For crackable feedstock gas The cracking reaction formula can crack the raw material gas. molar coefficient, For crackable feedstock gas The molar coefficient of the pyrolysis gas products in the pyrolysis reaction formula.

[0009] Preferably, the equivalent adjustment amount of downstream air extraction is expressed as: The equivalent adjustment amount of the upstream intake is expressed as: in, This is the adjustment factor for the upstream intake. For allocation coefficients, This is the equivalent adjustment amount for downstream air extraction. This is the equivalent adjustment amount of the upstream intake. This represents the total equivalent pressure increase trend within the furnace.

[0010] Preferred, The actual pumping rate of the constant pumping device and Total intake setting at any time They are represented as follows: in, This is the base pumping rate of the pumping device. It is the adjustment coefficient of the pumping rate on the equivalent adjustment amount of the downstream side pumping. This is the pressure feedback correction factor; for Pressure deviation inside the furnace at any given time; It is the reduction coefficient of the equivalent adjustment of the upstream intake to the total intake supply flow rate; This refers to the total supply flow rate of the raw material gas.

[0011] Preferred, The time allocation coefficient is expressed as: in, For allocation coefficients, The pressure sensitivity weight for downstream air extraction. The pressure sensitivity weighting of the upstream crackable feedstock gas. To achieve the equivalent gas increase from pyrolysis, for The first derivative of the time-specific spectral information.

[0012] The present invention also provides a dynamic pressure stabilization control system for a closed plasma furnace. The control system adopts the above-mentioned control method and includes a pressure detection device, a plasma furnace, a mixing tank, a PID control cabinet, a pyrolysis pressurization detection unit, a characteristic spectral information detection device, a pumping device, and a gas supply device. The upstream side of the plasma furnace is connected to a gas supply device via a mixing tank. The gas supply device includes at least two raw material gas supply pipelines. The downstream side of the plasma furnace is connected to an extraction device. The characteristic spectral information detection device collects the characteristic spectral information of active metals in the reaction region of the plasma furnace in real time, and calculates the volatilization equivalent gas increase caused by the enhanced volatilization of active metals based on the first derivative of the characteristic spectral information. The pressure detection device is used to detect the actual pressure inside the plasma furnace in real time. The cracking pressurization detection unit is used to calculate the equivalent gas increase generated by cracking pressurization of all crackable feed gas. The PID control cabinet calculates the equivalent adjustment amount of downstream side air extraction and the equivalent adjustment amount of upstream side air intake based on the allocation coefficient, and calculates the actual air extraction rate of the air extraction device based on the equivalent adjustment amount of downstream side air extraction and the pressure deviation in the furnace, and calculates the total air intake setpoint based on the equivalent adjustment amount of upstream side air intake.

[0013] The application of the technical solution of the present invention has the following beneficial effects: The control method of the present invention is a dual-disturbance coupled control that simultaneously considers the pressurization of active metal volatilization and the pressurization of raw material gas cracking. This not only reflects the real pressurization source in the furnace more accurately, but also improves the ability to suppress gas pressure fluctuations in the furnace under complex operating conditions through bidirectional linkage between downstream gas extraction and upstream gas intake, thereby further enhancing process stability, control accuracy and equipment operation safety.

[0014] The control method of this invention can identify in advance the rising trend of furnace gas pressure caused by enhanced volatilization of reactive metals and the cracking and decomposition of raw material gases such as methane and ammonia, rather than passively adjusting the pressure only after it has already increased. This method simultaneously adjusts the pressure-increasing factors bidirectionally by drawing gas from the downstream side and introducing gas from the upstream side, reducing pressure disturbances caused by the superposition of volatilization of reactive metals and cracking of raw material gases, and improving the stability and controllability of the closed plasma high-temperature reaction process. This method effectively reduces discharge instability, process parameter drift, reaction state fluctuations, and overpressure risks caused by abnormal increases in furnace pressure, improving equipment operating safety and continuous operation capability.

[0015] This invention also provides another dynamic pressure stabilization control method for a closed plasma furnace, aiming to solve the problem that existing pressure feedback regulation methods lack the ability to identify and actively intervene in early changes in the reaction region, resulting in regulation lag. The specific technical solution is as follows: A dynamic pressure stabilization control method for a closed plasma furnace, wherein a gas extraction device for extracting gas from the furnace is connected downstream of the plasma furnace, and a gas supply device for supplying at least one raw material gas to the furnace is connected upstream of the plasma furnace, the control method comprising: Collection furnace Always Lively Metal The characteristic spectral information is used, and the first derivative of the characteristic spectral information is used as a criterion for determining active metals. Basis for the impact of enhanced volatilization on furnace pressure; The pumping device is set based on the first derivative of characteristic spectral information. The theoretical pumping rate at any given time; Get The pressure deviation between the target pressure and the actual pressure inside the furnace at any given time; The theoretical pumping rate of the pumping device is corrected based on the pressure deviation to obtain... The actual pumping rate of the pumping device at all times.

[0016] The present invention also provides another dynamic pressure stabilization control system for a closed plasma furnace. The control system adopts the control method described above and includes a pressure detection device, a plasma furnace, a mixing tank, a PID control cabinet, a characteristic spectral information detection device, a pumping device, and a gas supply device. The upstream side of the plasma furnace is connected to a gas supply device via a mixing tank. The gas supply device includes at least one raw material gas supply pipeline. The downstream side of the plasma furnace is connected to an extraction device. The characteristic spectral information detection device collects the characteristic spectral information of active metals in the reaction area of ​​the plasma furnace in real time, and judges the degree of enhanced volatilization of active metals based on the first derivative of the characteristic spectral information. The pressure detection device is used to detect the actual pressure inside the plasma furnace in real time. The PID control cabinet calculates the actual pumping rate of the pumping device based on the first derivative of the characteristic spectral information and the pressure deviation inside the furnace.

[0017] The application of the technical solution of the present invention has the following beneficial effects: The control method of this invention can directly correlate the rate of change of the characteristic spectral intensity of reactive metals with the pumping rate of the pumping device, thereby achieving the purpose of adjusting the pumping rate of the pumping device in real time according to the rate of change of the characteristic spectral intensity. In addition, since the enhanced volatilization of reactive metals usually manifests first as a change in the corresponding characteristic spectral information in the reaction area, and then as a change in the overall gas pressure in the furnace, the control method of this invention can increase the pumping rate in advance based on the enhanced volatilization trend of reactive metals before the overall pressure in the furnace increases significantly, thereby achieving proactive prediction and stable control of the gas pressure in the furnace.

[0018] The control method of the present invention is applicable to the early identification and stable adjustment of the rise in furnace pressure caused by the volatilization of active metals during closed high-temperature plasma reaction, thereby maintaining the furnace pressure within the set range, ensuring stable discharge, smooth reaction and equipment safety.

[0019] The control method of the present invention is particularly applicable to high-temperature reaction processes of volatile and active metals such as magnesium, but is not limited to magnesium systems. It can also be extended to other closed high-temperature reaction scenarios with similar volatilization and pressurization problems.

[0020] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a flowchart of the dynamic voltage stabilization control method for the closed plasma furnace in Example 1; Figure 2 This is a schematic diagram of the dynamic voltage stabilization control system of the closed plasma furnace in Example 2; Figure 3 This is a flowchart of the dynamic voltage stabilization control method for the closed plasma furnace in Example 3; Figure 4 This is a schematic diagram of the dynamic voltage stabilization control system of the closed plasma furnace in Example 4; The components include: 1. Pressure detection unit; 2. Plasma furnace; 3. Filter; 4. Proportional regulating valve; 5. Vacuum pump; 6. Mixing tank; 7. Check valve; 8. Mass flow controller; 9. Ball valve; 10. Pressure reducing valve; 11. Gas storage tank; 12. PID control cabinet; 13. Vacuum pump frequency converter; 14. Spectrometer; 15. Characteristic spectral line extraction unit; 16. First derivative calculation unit; 17. Pyrolysis pressurization detection unit; and 18. Volatilization pressurization calculation unit. Detailed Implementation

[0022] To facilitate understanding of the present invention, a more complete description is provided below, along with preferred embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0024] Example 1: See Figure 1 This embodiment provides a dynamic pressure stabilization control method for a closed plasma furnace. A gas extraction device for drawing gas from the furnace is connected downstream of the plasma furnace, and a gas supply device for supplying at least one raw material gas to the furnace is connected upstream of the plasma furnace. The control method includes: Collection furnace Always Lively Metal Characteristic spectral information , to use characteristic spectral information first derivative As a way to determine active metals Basis for the impact of enhanced volatilization on furnace pressure; First derivative based on characteristic spectral information Set the air extraction device in Theoretical pumping rate at time ; Get The pressure deviation between the target pressure and the actual pressure inside the furnace at any given time ; Based on pressure deviation The theoretical pumping rate of the pumping device Make corrections to obtain The actual pumping rate of the constant pumping device .

[0025] During high-temperature plasma reactions, enhanced volatilization of reactive metals typically manifests first as changes in the corresponding characteristic spectral information within the reaction region, and later as changes in the overall furnace pressure. Therefore, the control method in this embodiment no longer relies solely on pressure sensors for hysteretic feedback adjustment of the actual pressure, but instead acquires real-time data on the target reactive metal. The curve of characteristic spectral information (i.e., characteristic spectral intensity) changing over time is obtained, and the derivative of this curve is extracted as a criterion for determining the activity of metals. This is a precursor signal to increased volatility and an impending rise in furnace pressure.

[0026] Assuming active metals exist The characteristic spectral intensity at time t is ,right After normalization, we get , first derivative with time It can be represented as: Under discrete sampling conditions, the first derivative It can be approximated as: in, Indicates the first The time of each sampling Indicates the first The time of each sampling Indicates the first The normalized value of the characteristic spectral intensity of the subsample. Indicates the first Normalized values ​​of the characteristic spectral intensities of the subsampled samples; , and All units are , The unit is Characteristic spectral intensity The unit is au; , and All are dimensionless.

[0027] In this embodiment, the first derivative of the characteristic spectral intensity versus time curve is used. As a way to determine active metals The system provides early signals regarding the degree of volatilization enhancement and the upward trend of gas pressure inside the furnace, and sets the theoretical extraction rate of the extraction device accordingly. This transforms traditional hysteresis feedback regulation into active prediction and stable control of the gas pressure inside the furnace, which can effectively stabilize the gas pressure inside the furnace and ensure the normal progress of the reaction.

[0028] Preferably, the air extraction device includes a vacuum pump or an induced draft fan. The vacuum pump or induced draft fan can change the air extraction rate by adjusting the operating frequency through frequency conversion, or by dynamically adjusting the valve opening in the air extraction pipeline.

[0029] This embodiment uses a variable frequency vacuum pump as an example. Changing the operating frequency of the vacuum pump via a frequency converter alters the pumping speed. Therefore, this embodiment uses the theoretical operating frequency of the vacuum pump. with the first derivative The mapping relationship between them is set as follows: in, Describing the first derivative The unit.

[0030] Based on the pre-set mapping relationship, it is possible to... First derivative at time t set up The theoretical operating frequency of a vacuum pump When active metals When the rate of change of the characteristic spectral intensity is small, the vacuum pump maintains a low operating frequency; when the first derivative... As the concentration gradually increases, it indicates that the metal is more active. If volatilization is enhanced and the furnace pressure tends to rise, then the theoretical operating frequency of the vacuum pump will be adjusted accordingly. The evacuation rate can be gradually increased to 35Hz, 40Hz, 45Hz or 50Hz to achieve advance adjustment of the gas pressure inside the furnace.

[0031] It should be noted that the above is only the first derivative set in this embodiment. With respect to the theoretical operating frequency of the vacuum pump The mapping relationship between the characteristic spectral intensity and the theoretical operating frequency of the vacuum pump can be flexibly adjusted by those skilled in the art according to the actual application scenario, so that the mapping relationship between the rate of change of characteristic spectral intensity and the theoretical operating frequency of the vacuum pump meets the actual control requirements. At the same time, those skilled in the art can also set more or fewer first derivative judgment thresholds as needed, thereby achieving a more refined or broader partitioning of the theoretical operating frequency of the vacuum pump.

[0032] Similarly, when adjusting the pumping rate by changing the valve opening, a theoretical valve opening can also be set. with the first derivative The mapping relationship between them is used to achieve the result based on the first derivative. The purpose of adjusting the valve opening in the extraction pipeline in real time is to meet the need for dynamic adjustment of the extraction rate.

[0033] Furthermore, to improve the accuracy of furnace pressure control, this embodiment also uses real-time pressure deviation to measure the theoretical pumping rate of the pumping device. Adjustments are made to ensure that the gas pressure inside the furnace is closer to the preset control target.

[0034] Specifically, the pressure deviation Represented as: in, express The actual pressure inside the furnace at all times Obtained by measurement using a pressure sensor; Indicates the target pressure inside the furnace. The preset pressure value, i.e., the air pressure control target; , and All units are .

[0035] Based on this, The actual pumping rate of the constant pumping device Represented as: in, This is the pressure feedback correction factor, and its unit is... To ensure Item and The dimensions of the items are consistent; the actual pumping rate is... That is The set value of the air extraction rate of the air extraction device at all times. and The unit is .

[0036] Taking adjusting the pumping speed by changing the operating frequency of the vacuum pump as an example, The actual operating frequency of the vacuum pump Represented as: in, This is the pressure feedback correction factor, and its unit is... In this embodiment Take 1.5 This is to achieve the actual operating frequency It is limited to the operating range of the air extraction device.

[0037] Similarly, when adjusting the pumping rate by changing the valve opening, those skilled in the art can also base their understanding on... To calculate and obtain Real valve opening at any given moment for: in, This represents the theoretical valve opening, expressed in degrees (°). Based on its first derivative The mapping relationship between them is determined; the pressure feedback correction coefficient is determined. The unit is .

[0038] It should be noted that in some embodiments, characteristic spectral information may not be included. Normalization is performed directly on the characteristic spectral information. It is also feasible to calculate the first derivative and then determine the theoretical pumping rate based on the mapping relationship between the first derivative and the operating frequency of the vacuum pump or the valve opening.

[0039] In this embodiment, the active metal can be lithium, sodium, potassium, magnesium, calcium, zinc, etc. The control method of this embodiment can directly correlate the rate of change of the characteristic spectral intensity of the active metal with the pumping rate of the pumping device, so as to achieve the purpose of adjusting the pumping rate of the pumping device in real time according to the rate of change of the characteristic spectral intensity. In addition, since the enhanced volatilization of active metals usually manifests first as a change in the corresponding characteristic spectral information in the reaction area, and then as a change in the overall gas pressure in the furnace, the control method of this embodiment can increase the pumping rate in advance according to the enhanced volatilization trend of the active metal before the overall pressure in the furnace increases significantly, thereby achieving active prediction and stable control of the gas pressure in the furnace.

[0040] The control method in this embodiment is applicable to the early identification and stable adjustment of the furnace pressure rise caused by the volatilization of active metals during the closed high-temperature plasma reaction process, thereby maintaining the furnace pressure within the set range and ensuring stable discharge, smooth reaction and equipment safety.

[0041] The control method of this embodiment is particularly applicable to high-temperature reaction processes of volatile and active metals such as magnesium, but it is not limited to magnesium systems. It can also be extended to other closed high-temperature reaction scenarios with similar volatilization and pressurization problems.

[0042] Example 2: like Figure 2 As shown, this embodiment provides a dynamic pressure stabilization control system for a closed plasma furnace. The control system adopts the control method in Embodiment 1. The control system includes a pressure detection element 1, a plasma furnace 2, a mixing tank 6, a PID control cabinet 12, a characteristic spectral information detection device, a gas extraction device, and a gas supply device. The upstream side of the plasma furnace 2 is connected to a gas supply device via a mixing tank 6. The gas supply device includes at least one raw material gas supply pipeline. The downstream side of the plasma furnace 2 is connected to an extraction device. The characteristic spectral information detection device collects the characteristic spectral information of active metals in the reaction region of plasma furnace 2 in real time, and judges the degree of enhanced volatilization of active metals based on the first derivative of the characteristic spectral information. The pressure detection element 1 is used to detect the actual pressure inside the plasma furnace 2 in real time. The PID control cabinet 12 calculates the current... based on the first derivative of the characteristic spectral information and the pressure deviation inside the plasma furnace 2. The actual pumping rate of the pumping device at all times.

[0043] Preferably, in this embodiment, the pressure detection element 1 is a vacuum gauge, which is electrically connected to the PID control cabinet 12, thereby transmitting the real-time acquired actual pressure signal to the PID control cabinet 12. The PID control cabinet 12 can then calculate the pressure based on the actual pressure and the target pressure. The pressure deviation inside the furnace is monitored in real time so that the extraction rate of the extraction device can be corrected accordingly.

[0044] Preferably, the downstream side of the plasma furnace 2 is connected to an exhaust pipe, and an exhaust device is provided on the exhaust pipe; the exhaust device includes a vacuum pump or an induced draft fan, and the vacuum pump or induced draft fan can change the exhaust rate by adjusting the operating frequency through frequency conversion, or by dynamically adjusting the valve opening in the exhaust pipe.

[0045] See Figure 2 In this embodiment, the pumping device includes a vacuum pump 5 and a vacuum pump frequency converter 13. The pumping pipeline is sequentially equipped with a filter 3, a proportional regulating valve 4, and the vacuum pump 5 along the airflow direction. The filter 3 is used to filter the gas in the pumping pipeline. The proportional regulating valve 4 and the vacuum pump frequency converter 13 are both electrically connected to the PID control cabinet 12. The vacuum pump frequency converter 13 adjusts the operating frequency of the vacuum pump 5 according to the frequency conversion command of the PID control cabinet 12, thereby changing the pumping rate. Simultaneously, the proportional regulating valve 4 can precisely adjust the flow rate of the fluid in the pipeline according to the PID control cabinet 12 to assist in adjusting the pumping rate of the pumping pipeline.

[0046] Preferably, the extraction device can also be a combination of an induced draft fan and a regulating valve. The induced draft fan provides negative pressure to extract gas from the plasma furnace, and the extraction rate of the extraction pipeline can be adjusted by adjusting the opening of the regulating valve.

[0047] Based on the clear principle in Example 1 that the gas pressure inside the plasma furnace 2 can be stabilized by adjusting the pumping rate, those skilled in the art can flexibly adjust and design the pumping device (pumping pipeline) based on common sense.

[0048] Preferably, a single raw material gas supply pipeline includes, in sequence, a gas storage tank 11, a pressure reducing valve 10, a ball valve 9, a filter 3, a mass flow controller 8, and a one-way valve 7. The gas storage tank 11 stores the raw material gases participating in the reaction; the pressure reducing valve 10 controls the gas pressure in the pipeline; the ball valve 9 controls the pipeline's on / off state; the filter 3 filters the raw material gases; the mass flow controller 8 accurately measures and automatically and stably controls the mass flow rate of the raw material gases; and the one-way valve 7 ensures unidirectional flow of the raw material gases, preventing backflow. The raw material gas supply pipeline is configured according to the actual reaction requirements; the number of raw material gas supply pipelines corresponds to the number of types of raw material gases required for the reaction.

[0049] Preferably, the characteristic spectral information detection device includes a spectrometer 14, a characteristic spectral line extraction unit 15, and a first derivative calculation unit 16. The spectrometer 14 is used to acquire the characteristic spectral signals of active metals in the reaction region of the plasma furnace 2 in real time. The characteristic spectral line extraction unit 15 is used to extract the characteristic spectral intensity. The first derivative calculation unit 16 normalizes the characteristic spectral intensity as needed and calculates the first derivative of the characteristic spectral intensity. The PID control cabinet 12 can determine the volatilization trend of the active metal based on the first derivative of the characteristic spectral intensity, and calculate the current... The actual pumping rate of the pumping device at all times.

[0050] Preferably, the active metal in this embodiment can be lithium, sodium, potassium, magnesium, calcium, zinc, etc.

[0051] The operation steps of the dynamic voltage stabilization control system for the closed plasma furnace in this embodiment are as follows: 1) Pre-power-on checks and initial preparations First, check whether the connections between the water cooling system, compressed air system, plasma power supply, spectrometer, vacuum gauge, vacuum pump, pressure regulating valve, and PID control cabinet are normal, and confirm that the cables, power supply, gas lines, and signal lines are in working condition; check whether the spectral acquisition window, fiber optic probe, or observation port is clean, and confirm that the vacuum gauge, spectrometer, PID control cabinet, and operation panel are all in a startable state.

[0052] 2) Loading and reactor sealing After confirming that there are no residual samples or abnormal deposits inside the plasma furnace, restore the plasma furnace to atmospheric pressure, open the plasma furnace, load the active metal raw materials, reducing materials or related reactants to be processed into the crucible, boat or designated reaction area, and then close the chamber door and complete the sealing.

[0053] 3) Vacuuming and gas washing replacement Start the vacuum pump to evacuate the reactor; after reaching the preset vacuum level, inert gas can be introduced into the plasma furnace, and the vacuum can be evacuated again. Repeat this process one to several times to remove air, water vapor and impurity gases.

[0054] 4) Input process parameters and control parameters Input the parameters required for this experiment or operation on the touch screen, including target working air pressure, allowable fluctuation range, spectral sampling frequency, pressure sampling frequency, characteristic spectral line wavelength range, derivative calculation time window, derivative threshold, pressure alarm threshold, PID parameters, and upper and lower limits for air extraction adjustment.

[0055] When necessary, corresponding characteristic spectral lines and their judgment thresholds can be preset according to different metal types. Taking magnesium as an example, the characteristic spectral line wavelengths and corresponding derivative threshold ranges of magnesium can be preset for subsequent volatilization trend judgment.

[0056] 5) Establish an initial work atmosphere and basic pressure According to process requirements, inert gas, protective gas, or reactive gas is introduced into the plasma furnace to bring the furnace to the preset working pressure; at the same time, the basic pressure balance is established through the air pump and pressure regulating valve to maintain a relatively stable initial gas pressure environment in the plasma furnace before arc ignition.

[0057] 6) Arc ignition and high-temperature plasma reaction start-up The plasma power supply is activated and the arc is ignited, stabilizing the arc within the designated reaction zone. Once ignition is successful, the temperature in the reaction zone rises rapidly, and the active metal begins to heat, evaporate, be reduced, decompose, or undergo other gas-phase transformation reactions.

[0058] 7) Real-time acquisition of characteristic spectra of the target active metal After the plasma is in stable operation, the characteristic spectral information detection device continuously acquires the emission spectrum data of the reaction region and extracts the characteristic spectral intensity of the target active metal from it.

[0059] In this step, the target active metal can be magnesium or other volatile active metals. Taking magnesium as an example, the system extracts the peak intensity or integral intensity of the characteristic spectral lines of magnesium in real time and forms a spectral intensity curve that changes with time.

[0060] 8) Calculate the derivative of the characteristic spectral intensity versus time curve. The control system continuously processes the acquired characteristic spectral intensity sequence and calculates the first derivative, approximate slope, or differential rate of change of its time-varying curve.

[0061] The derivative can be calculated using continuous derivatives, or obtained through methods such as difference between adjacent time points, sliding window slope fitting, or differentiation after multi-point smoothing. Its essence lies in characterizing the rate and direction of change in characteristic spectral intensity, rather than simply focusing on the absolute spectral intensity value at a single moment.

[0062] The control system in this embodiment uses the derivative of the characteristic spectral intensity change curve over time as the basis for control judgment. Compared with only looking at the current pressure value or only looking at the spectral intensity at a certain moment, the derivative can more sensitively reflect the dynamic trend of local volatilization enhancement.

[0063] 9) Predict the upward trend of air pressure based on the derivative results. The PID control cabinet identifies the volatilization state of the reaction zone based on the magnitude, positive / negative change, and duration of the derivative value.

[0064] 10) Establish a composite control quantity of spectral feedforward + pressure feedback. After the trend judgment result is output, the control system reads the first derivative signal of the characteristic spectrum information as the feedforward input on the one hand, and continuously reads the actual pressure value of the pressure sensor as the feedback input on the other hand.

[0065] The first derivative of the characteristic spectral information is used to reflect the potential upward pressure trend over a future period, while the pressure feedback value reflects the deviation between the current actual pressure and the target pressure. The control system sends both types of signals into the control algorithm, thus avoiding control lag caused by relying solely on the current pressure feedback and avoiding erroneous adjustments caused by ignoring the actual pressure state based solely on the spectral signal.

[0066] 11) The PID control cabinet continuously and quantitatively adjusts the air extraction volume. The PID control cabinet outputs corresponding control commands based on the composite control quantity, adjusting the working frequency of the vacuum pump and the opening of the proportional control valve to make the pumping capacity change continuously, rather than simply starting and stopping.

[0067] in: The proportional element is used to respond quickly based on the current pressure deviation; The integral component is used to eliminate long-term deviations and keep the actual air pressure as close as possible to the target setpoint. The differential element is used to suppress rapid fluctuations and reduce overshoot.

[0068] 12) Continuous closed-loop correction during operation During the continuous reaction, the system continuously executes a cycle of spectral acquisition, derivative calculation, trend judgment, pressure feedback reading, and PID control output at a set frequency.

[0069] If the volatilization of reactive metals continues to increase, the system maintains a high pumping capacity; if volatilization weakens, the system gradually reduces the pumping capacity to prevent over-pumping and resulting in excessively low pressure; if short-term discharge fluctuations or reaction disturbances occur, the system can synchronously correct the control quantity based on the derivative signal and pressure deviation signal.

[0070] 13) Abnormal pressure monitoring and safety interlock In addition to normal pressure regulation and control, the system also has a safety threshold judgment logic. When the pressure exceeds the safety limit or the rate of pressure rise exceeds the preset limit, the system immediately triggers an alarm and executes protective actions.

[0071] Protective actions may include: rapidly increasing the opening of the extraction valve, increasing the output of the vacuum pump, reducing the plasma power, cutting off part of the gas intake, and extinguishing the arc and stopping the machine if necessary.

[0072] 14) Shutdown, evacuation, and reset after the reaction is complete After the reaction is complete, turn off the plasma power supply, stop heating or discharging, shut off the process gas inlet, and keep the pump running for a period of time to extract the residual vapor and reaction gas in the furnace. Then, according to the process requirements, refill the furnace with inert gas to atmospheric pressure, open the reactor to collect the material, and finally shut down the control cabinet, vacuum pump and related peripheral equipment.

[0073] In this embodiment, a gas extraction device is used to extract gas from the plasma furnace, while a gas supply device provides a stable supply of raw material gas to the plasma furnace, thereby creating a controlled flow direction and pressure gradient inside the plasma furnace. The vapor and powder products generated by the active metal are drawn away from the high-temperature reaction zone along a predetermined gas exit path under the traction of the outgoing carrier gas, and are continuously collected by the subsequent powder collection chamber, filter or collection cavity, thereby reducing the retention, backflow and random deposition of vapor inside the furnace, which helps to improve product collection efficiency and process continuity.

[0074] The control system in this embodiment can identify early signs of disturbance before the overall pressure inside the furnace has increased significantly, thus advancing the timing of control adjustments, improving the ability to identify pressure fluctuations in advance, and reducing control lag caused by relying solely on pressure feedback.

[0075] The control system in this embodiment can respond in advance to local disturbances caused by the volatilization of reactive metals, and can also perform closed-loop correction based on actual pressure deviations, thereby balancing the advance and accuracy of control, reducing erroneous adjustments and fluctuations, and improving the stability and reliability of furnace pressure control.

[0076] The control system in this embodiment helps to maintain the furnace pressure within a set range, reducing the impact of pressure fluctuations on the discharge state, reaction process, and process parameters. It also reduces the risk of abnormal pressure rise and overpressure, and improves the safety, stability, and continuous operation capability of the closed plasma high-temperature reaction process.

[0077] Example 3: For closed plasma high-temperature reaction systems, in addition to the volatilization of reactive metals due to heat causing an increase in furnace pressure, some raw material gases undergo cracking reactions under high temperature, plasma activation, or free radical action, which also leads to an increase in the total molar number of gases in the system, thereby causing an increase in furnace pressure. Therefore, simply increasing the pumping rate for pressure stabilization may still result in problems such as adjustment lag or large fluctuations under certain operating conditions.

[0078] In this embodiment, not only is the impact of the volatilization of reactive metals on the furnace pressure considered, but also the disturbance effect of the increase in the number of gas moles caused by the cracking, decomposition or gas phase transformation of the raw material gas during the reaction process on the furnace pressure. At the same time, the furnace pressure is stabilized by increasing the pumping capacity and reducing the total supply of raw material gas. The adjustment of the total flow rate of raw material gas, rather than adjusting the supply flow rate of crackable raw material gas alone, is to ensure that the ratio of each raw material gas does not change.

[0079] Specifically, the downstream side of the plasma furnace is connected to a gas extraction device for extracting gas from the furnace, and the upstream side of the plasma furnace is connected to a gas supply device for supplying at least two raw material gases to the furnace, such as... Figure 3 As shown, the control method includes: Collection furnace Always Lively Metal Characteristic spectral information , to use characteristic spectral information first derivative As a way to determine active metals Basis for the impact of enhanced volatilization on furnace pressure; According to the first derivative calculate Always Lively Metal Increased gas volume due to enhanced volatility ; according to The degree of cracking of all crackable feedstock gases in the furnace at all times is calculated to determine the equivalent gas increase from cracking. ; Based on the equivalent gas increase from evaporation Equivalent gas increase from cracking Calculate the total equivalent pressure increase trend in the furnace. ; based on Time allocation coefficient Total equivalent boost trend Calculate the equivalent adjustment amount of downstream side air extraction. Equivalent adjustment amount of upstream intake ; Based on the equivalent adjustment amount of downstream side air extraction and Calculation of pressure deviation inside the furnace at any time The actual pumping rate of the constant pumping device Based on the equivalent adjustment amount of the upstream intake. calculate Total intake setting at any time .

[0080] The control method of this embodiment will be described in detail below: Preferably, it is assumed that the active metal exist The characteristic spectral intensity at time t is ,right After normalization, we get , first derivative with time It can be represented as: Under discrete sampling conditions, the first derivative It can be approximated as: in, Indicates time, Indicates the first The time of each sampling Indicates the first The time of each sampling Indicates the first The normalized value of the characteristic spectral intensity of the subsample. Indicates the first Normalized values ​​of the characteristic spectral intensities of the subsampled samples; , and All units are , The unit is Characteristic spectral intensity The unit is au; , and All are dimensionless.

[0081] Furthermore, active metals The volatile equivalent gas increase characterized by the first derivative of the characteristic spectral intensity versus time curve. Represented as: in, Indicates active metals exist Normalized value of the spectral intensity of the time feature; This is the proportionality coefficient that maps the first derivative of the characteristic spectral information to the volatile equivalent gas increase. The unit is , The unit is .

[0082] It should be noted that in some embodiments, characteristic spectral information may not be included. Instead of performing normalization, it directly processes the characteristic spectral information. Calculate the first derivative and use it to calculate the evaporation-equivalent gas increase. , is represented as: in, Characteristic spectral intensity The first derivative (i.e., the first derivative obtained without normalization) is expressed in units of au / s; at this point, the proportionality coefficient mapping the first derivative of the characteristic spectral information to the volatile equivalent gas increase is... The unit is expressed as .

[0083] In contrast, for characteristic spectral information Normalization is performed before calculating the first derivative, making the dimensions of the parameters relatively simpler.

[0084] Taking gases such as methane and ammonia as examples, they can undergo the following types of decomposition or cracking processes under high temperature or plasma conditions: The above reaction increases the number of moles of gaseous products per unit feed, thereby increasing the total gas volume in the furnace and consequently increasing the pressure. (Using methane...) For example, Methane can be cracked to produce Hydrogen; ammonia For example, Ammonia can be decomposed into Nitrogen and Hydrogen, the total number of moles of gas is from Increase to Therefore, this type of reaction can produce an additional pressurization effect on the gas pressure inside the furnace, and this effect may coexist with the pressurization effect of the volatilization of active metals.

[0085] Assume that the total amount of feed gas participating in the pyrolysis is species, first The inlet flow rate of the feed gas participating in the pyrolysis is , Time of the first The degree of pyrolysis of the feedstock gas in the furnace is used as a measure of its pyrolysis performance. This indicates that its value range is... ,in Indicates the gas involved in the cracking process. Almost no pyrolysis occurred. Indicates the gas involved in the cracking process. If the preset complete pyrolysis state is reached, then The equivalent gas increase caused by the cracking of all crackable feedstock gases in the furnace at all times Represented as: in, This represents the gas cracking boosting coefficient, which is related to the change in the number of gas moles before and after the specific reaction. Indicates the first The degree of cracking of a type of crackable feedstock gas; Indicates the first A type of crackable feedstock gas in The intake airflow at any given time; and All units are , and All are dimensionless.

[0086] Preferably, for methane cracking reaction It is acceptable This means that the amount of gas produced after the cracking of a unit of methane is considered to increase by 1 time; for the ammonia cracking reaction... It is acceptable This means that the decomposition of a single unit of ammonia gas is equivalent to doubling the molar amount of gas. For other gas-phase reactions that lead to an increase in the number of gas moles, the corresponding gas cracking boosting coefficient can also be predetermined based on their stoichiometric relationships. .

[0087] thus, Total equivalent pressure increase trend in the furnace at any time This can be expressed as: Furthermore, due to the total equivalent boost trend... The system is composed of both pressurization for the volatilization of reactive metals and pressurization for the cracking of raw material gases; therefore, this embodiment does not necessarily involve... Instead of applying all of it directly to the extraction or total intake regulation, this total equivalent boost trend is used. Adjustments are made between the downstream side's extraction and the upstream side's intake to ensure that the two methods of increasing the extraction rate and reducing the total intake flow rate can work in coordination to maintain the gas pressure balance in the furnace, without causing insufficient or excessive adjustment.

[0088] First, define the total equivalent boost trend. The equivalent regulation distribution relationship between downstream air extraction and upstream air intake is as follows: in, This is the equivalent adjustment amount for downstream air extraction; This is the equivalent adjustment amount for the upstream intake; and All units are ; This is the adjustment factor for upstream intake, used to convert the total intake reduction into an equivalent pressure stabilization contribution comparable to downstream extraction. Dimensionless.

[0089] Further introduce allocation coefficient ,in Then we have: Therefore, when When it is large, the total equivalent boost pressure trend is More is allocated to the downstream side, and the system tends to stabilize pressure by increasing the pumping rate; when When the value is small, the total equivalent boost pressure trend is... More gas is allocated to the upstream side, and the system tends to suppress subsequent pressurization sources by reducing the total intake airflow. When both types of disturbances exist simultaneously, the system coordinates and adjusts the two methods according to the above allocation relationship to achieve dynamic balance of gas pressure in the furnace.

[0090] Based on this, The actual pumping rate of the constant pumping device and Total intake setting at any time They are represented as follows: in, This is the base pumping rate of the pumping device. It is the adjustment coefficient of the pumping rate on the equivalent adjustment amount of the downstream side pumping. This is the pressure feedback correction factor; for Pressure deviation inside the furnace at any given time; It is the reduction coefficient of the equivalent adjustment of the upstream intake to the total intake supply flow rate; The total supply flow rate of the raw material gas base; , , and All units are The actual pumping rate That is The set value of the pumping rate of the pumping device at all times; The unit is , and All are dimensionless.

[0091] Preferably, the pressure deviation Represented as: in, express The actual pressure inside the furnace at all times Obtained by measurement using a pressure sensor; Indicates the target pressure inside the furnace. The preset pressure value, i.e., the air pressure control target; , and All units are .

[0092] Similar to Embodiment 1, the air extraction device includes a vacuum pump or an induced draft fan. The vacuum pump or induced draft fan can change the air extraction rate by adjusting the operating frequency through frequency conversion, or by dynamically adjusting the valve opening in the air extraction pipeline.

[0093] When the frequency is changed to adjust the pumping speed The actual operating frequency of the vacuum pump or induced draft fan at all times Represented as: in, This is the basic operating frequency of the air extraction device; This is the adjustment coefficient of the equivalent adjustment amount of downstream air extraction on the operating frequency of the air extraction device. Used to Convert the unit of the item to Hz. The unit is Hz / (L / min); This is the pressure feedback correction factor, and its unit is... ; for Pressure deviation inside the furnace at any given time.

[0094] Similarly, when adjusting the pumping speed by changing the valve opening, Real-time valve opening Represented as: in, This represents the basic valve opening. and The units are all in degrees; This is the adjustment coefficient of the valve opening based on the equivalent adjustment amount of downstream air extraction. The unit is , Used to Convert the units of the items to degrees; This is the pressure feedback correction factor, and its unit is... ; for Pressure deviation inside the furnace at any given time.

[0095] Preferably, the adjustment conversion factor of the upstream air intake The adjustment conversion factor, used to convert the upstream intake reduction into an equivalent pressure stabilization contribution comparable to the downstream extraction, is a key parameter for ensuring coordinated operation of the two methods. This embodiment determines the adjustment conversion factor using a double-step comparison calibration method. Specifically: The air extraction rate of the air extraction device is The total supply flow rate of raw material gas is Once the furnace pressure stabilizes (i.e., pressure fluctuations are within the set allowable range), maintain a constant total supply flow rate of raw material gas on the upstream side, and increase the extraction rate of the extraction device. The steady-state pressure change was measured. Define the pressure sensitivity of downstream air extraction. for: in, The unit is kPa. The unit is L / min. The unit is kPa / (L / min); The air extraction rate of the air extraction device is The total supply flow rate of raw material gas is After the furnace pressure stabilizes, the extraction rate of the extraction device remains constant, while the total supply flow rate of raw material gas on the upstream side is reduced. The steady-state pressure change was measured. Define the pressure sensitivity of the upstream intake. for: in, The unit is kPa. The unit is L / min. The unit is kPa / (L / min); The adjustment factor for the upstream intake is defined as follows: in, This indicates the pressure change caused by a unit change in pumping rate. This indicates the pressure change caused by a unit change in total intake air. Therefore, The physical meaning is how many units of pressure stabilization contribution on the extraction side are equivalent to a unit of total intake air reduction, thereby achieving... and It allows for addition and comparison on the same basis.

[0096] Preferably, the allocation coefficient Used to determine the total equivalent boost trend. How to allocate resources between the upstream and downstream sides? In this embodiment, the allocation coefficient... Dynamic calculations are performed based on the relative magnitudes of the pressurization contributions from the volatilization of active metals and the pressurization contributions from cracking: in, for The first derivative of the characteristic spectral information at time (i.e., without considering the characteristic spectral intensity) The first derivative obtained after normalization is expressed in au / s. The pressure sensitivity weight for downstream air extraction. The unit is ; The pressure sensitivity weighting of the upstream crackable feedstock gas. The unit is kPa / (L / min).

[0097] Specifically, if the denominator term A value of 0 indicates that no pressurization disturbances from the volatilization of reactive metals or the cracking of feedstock gases have been detected. Correspondingly, the total equivalent pressurization trend... The equivalent adjustment amount of downstream side air extraction and the equivalent regulation amount of upstream intake. Both are 0, and the system maintains the existing pumping rate and inlet flow rate; when there is still a deviation in the furnace pressure, the system adjusts the pressure deviation accordingly. Continue making adjustments.

[0098] Specifically, weight This was determined through steam disturbance experiments, specifically: Modifying the active metal under conditions where the effects of pyrolysis are relatively stable The volatility intensity, recorded The amount of pressure increase within its subsequent time window Then the weight Represented as: Furthermore, if the conditions are met within the specified time window If the pyrolysis effect is relatively stable, then the pyrolysis effect is considered relatively stable; among them, This represents the maximum value of the equivalent gas increase from pyrolysis within the calibration time window. This represents the minimum equivalent gas increase from pyrolysis within the calibration time window. This represents the average value of the equivalent gas increase from pyrolysis within the calibration time window. Indicates the threshold for judgment. This prevents positive numbers with a denominator of zero. , The units are all L / min. The unit is kPa. Dimensionless.

[0099] Specifically, weight This was determined through a splitting perturbation experiment, specifically: In active metals Under conditions where volatility effects are relatively stable, the input flow rate of the crackable gas is varied, and records are kept. The amount of pressure increase within its subsequent time window Then the weight Represented as: Furthermore, if the conditions are met within the specified time window or The effects of the volatilization of active metals are considered relatively stable; among them, This represents the maximum value of the characteristic spectral intensity within the calibration time window. This represents the minimum characteristic spectral intensity within the calibration time window. This represents the average value of the characteristic spectral intensity within the calibration time window. and All of these are set judgment thresholds. This prevents positive numbers with a denominator of zero. , The unit is au. The unit is au / s. The unit is kPa. Dimensionless.

[0100] Preferred, the first A type of crackable feedstock gas in Fragmentation degree coefficient at time The determination method is as follows: Get The feedstock gas can be cracked at any time Inlet molar flow rate at the furnace inlet And detect the crackable raw material gas at the furnace outlet. molar flow rate of pyrolysis gas products Then the raw material gas can be cracked. exist Fragmentation degree coefficient at time Represented as: in, For crackable feedstock gas The cracking reaction formula can crack the raw material gas. molar coefficient, For crackable feedstock gas The molar coefficient of the pyrolysis gas products in the pyrolysis reaction formula; and All units are The inlet molar flow rate and the molar flow rate of pyrolysis gas products All of these can be calculated using the corresponding gas's volumetric flow rate, pressure, and temperature.

[0101] Furthermore, taking the methane cracking reaction as an example: If hydrogen, a product of pyrolysis, is used as an indicator component, then... The portion of hydrogen molar flow rate at the outlet that is newly generated by methane cracking is: The inlet molar flow rate of methane is , then because methane cracking produces Hydrogen, then methane Fragmentation degree coefficient at time for: Furthermore, taking ammonia cracking reaction as an example: If hydrogen, a product of pyrolysis, is used as an indicator component, then... The portion of hydrogen molar flow rate at the outlet that is newly generated by ammonia cracking is: The inlet ammonia molar flow rate is Since 2 mol of ammonia decomposes into 3 mol of hydrogen, ammonia in Fragmentation degree coefficient at time for: If nitrogen gas, a product of pyrolysis, is used as an indicator component, then... The additional portion of nitrogen molar flow rate at the outlet due to ammonia cracking is: The inlet ammonia molar flow rate is Because 2 mol of ammonia decomposes into 1 mol of nitrogen, therefore ammonia in Fragmentation degree coefficient at time for: Those skilled in the art will understand that, in the ammonia cracking reaction process, using hydrogen or nitrogen as an indicator component, the calculated cracking degree coefficient... They are consistent.

[0102] The active metal in this embodiment can be lithium, sodium, potassium, magnesium, calcium, zinc, etc.

[0103] The control method in this embodiment is a dual-disturbance coupling control that simultaneously considers the pressurization from the volatilization of reactive metals and the pressurization from the cracking of raw material gases. This not only reflects the true pressurization source in the furnace more accurately, but also improves the ability to suppress gas pressure fluctuations in the furnace under complex operating conditions through the bidirectional linkage between downstream gas extraction and upstream gas intake, thereby further enhancing process stability, control accuracy, and equipment operation safety.

[0104] The control method in this embodiment can identify in advance the rising trend of furnace gas pressure caused by enhanced volatilization of reactive metals and the cracking and decomposition of raw material gases such as methane and ammonia, rather than passively adjusting the pressure only after it has already increased. This control method bidirectionally adjusts the pressure-boosting factors by simultaneously drawing gas from the downstream side and introducing gas from the upstream side, reducing pressure disturbances caused by the superposition of volatilization of reactive metals and cracking of raw material gases, and improving the stability and controllability of the closed plasma high-temperature reaction process. This control method effectively reduces discharge instability, process parameter drift, reaction state fluctuations, and overpressure risks caused by abnormal increases in furnace pressure, improving equipment operating safety and continuous operation capability.

[0105] Example 4: like Figure 4 As shown, this embodiment provides a dynamic pressure stabilization control system for a closed plasma furnace. The control system adopts the control method in embodiment 3. The control system includes a pressure detection element 1, a plasma furnace 2, a gas mixing tank 6, a PID control cabinet 12, a pyrolysis pressurization detection unit 17, a characteristic spectral information detection device, a gas extraction device, and a gas supply device. The upstream side of the plasma furnace 2 is connected to a gas supply device via a mixing tank 6. The gas supply device includes at least two raw material gas supply pipelines. The downstream side of the plasma furnace 2 is connected to an extraction device. The characteristic spectral information detection device collects the characteristic spectral information of the active metal in the reaction region of the plasma furnace 2 in real time, and calculates the volatilization equivalent gas increase caused by the enhanced volatilization of the active metal based on the first derivative of the characteristic spectral information. The pressure detection element 1 is used to detect the actual pressure inside the plasma furnace 2 in real time. The cracking pressurization detection unit 17 is used to calculate the equivalent gas increase generated by cracking pressurization of all crackable raw material gases; The PID control cabinet 12 calculates the equivalent adjustment amount of downstream side air extraction and the equivalent adjustment amount of upstream side air intake according to the allocation coefficient, and calculates the actual air extraction rate of the air extraction device according to the equivalent adjustment amount of downstream side air extraction and the pressure deviation in the furnace, and calculates the total air intake setpoint according to the equivalent adjustment amount of upstream side air intake.

[0106] Compared with Example 2, the characteristic spectral information detection device in this example further includes a volatile pressurization calculation unit 18, which is used to calculate the equivalent gas increase in volatiles based on the first derivative of the characteristic spectral intensity change curve over time.

[0107] Preferably, the pyrolysis pressurization detection unit 17 is electrically connected to the PID control cabinet 12. The pyrolysis pressurization detection unit 17 includes a pyrolysis gas product detection device and a pyrolysis pressurization calculation unit. The pyrolysis gas product detection device is used to detect the molar flow rate of the pyrolysis gas products at the furnace outlet in order to confirm the degree of pyrolysis coefficient. The cracking pressurization calculation unit calculates the pressure based on the intake flow rate of the crackable feedstock gas and the cracking degree coefficient. And calculate the equivalent gas increase generated by the pyrolysis pressurization of all pyrolysis raw material gases by setting the gas pyrolysis boosting coefficient.

[0108] The active metal in this embodiment can be lithium, sodium, potassium, magnesium, calcium, zinc, etc.

[0109] For any other details not described in this embodiment, please refer to Embodiment 2.

[0110] The operation steps of the dynamic voltage stabilization control system for the closed plasma furnace in this embodiment are as follows: 1) Pre-power-on checks and initial preparations First, check whether the connections between the water cooling system, compressed air system, plasma power supply, spectrometer, vacuum gauge, vacuum pump, vacuum pump inverter, mass flow controller, proportional control valve, and PID control cabinet are normal, and confirm that the cables, power supply, gas lines, signal lines, and control loops are in working condition; check whether the spectral acquisition window, fiber optic probe, or observation port is clean, and confirm that the vacuum gauge, spectrometer, PID control cabinet, mass flow controller, etc. are all in a startable state.

[0111] 2) Loading and reactor sealing After confirming that there are no residual samples or abnormal deposits inside the plasma furnace, restore the plasma furnace to atmospheric pressure, open the reaction chamber, and load the active metal raw materials, reducing materials or related reactants to be processed into the crucible, boat or designated reaction area, then close the door and complete the sealing.

[0112] 3) Vacuuming and gas washing replacement Start the vacuum pump to evacuate the plasma furnace; after reaching the preset vacuum level, inert gas can be introduced into the plasma furnace, and the vacuum can be evacuated again. Repeat this process one to several times to remove air, water vapor and impurity gases.

[0113] 4) Input process parameters and control parameters Input the parameters required for this experiment or operation on the touch screen, including target working gas pressure, allowable gas pressure fluctuation range, spectral sampling frequency, pressure sampling frequency, inlet flow rate setting, characteristic spectral wavelength range, derivative calculation time window, derivative threshold, cracking pressurization judgment threshold, pressure alarm threshold, PID parameters, upper and lower limits of vacuum pump inverter frequency, and raw material gas flow reduction range, etc.

[0114] When necessary, corresponding characteristic spectral lines and their judgment thresholds can be preset according to different metal types; corresponding cracking boosting coefficients can be preset according to different raw material gas types. Taking magnesium as an example, the characteristic spectral line wavelength and corresponding derivative threshold of magnesium can be preset; taking methane and ammonia as examples, their cracking boosting factors and gas supply reduction ratios can be preset for subsequent boosting trend judgment and linkage control.

[0115] 5) Establish an initial work atmosphere and basic pressure According to process requirements, inert gas, protective gas, or reactive gas is introduced into the plasma furnace to bring the furnace to the preset working pressure; at the same time, a basic pressure balance is established through a vacuum pump, frequency converter, and pressure regulating valve to maintain a relatively stable initial gas pressure environment in the plasma furnace before arc ignition.

[0116] When the system uses crackable feedstock gases such as methane and ammonia, the initial gas supply flow rate and allowable adjustment range of each feedstock gas can be set simultaneously to provide a reference value for subsequent linkage reduction control.

[0117] 6) Arc ignition and high-temperature plasma reaction start-up The plasma power supply is activated and the arc is ignited, stabilizing the arc within the designated reaction zone. Once ignition is successful, the temperature in the reaction zone rises rapidly, and the active metal begins to heat, evaporate, be reduced, decompose, or undergo other gas-phase transformation reactions.

[0118] During this process, in addition to the volatilization of reactive metals, some raw material gases may also undergo cracking or decomposition under high temperature, plasma activation, or free radical action, such as methane cracking and ammonia decomposition, which leads to an increase in the number of gas moles in the system and an additional increase in the gas pressure inside the furnace. This step marks the transition of the system from the "basic pressure stabilization stage" to the "reaction pressure stabilization stage".

[0119] 7) Real-time acquisition of characteristic spectra of the target active metal After the plasma is in stable operation, the characteristic spectral information detection device continuously acquires the emission spectrum data of the reaction region and extracts the characteristic spectral intensity of the target active metal from it.

[0120] In this step, the target active metal can be magnesium or other volatile active metals. Taking magnesium as an example, the system extracts the peak intensity or integral intensity of the characteristic spectral lines of magnesium in real time and forms a spectral intensity curve that changes with time.

[0121] 8) Calculate the derivative of the characteristic spectral intensity versus time curve. The control system continuously processes the acquired characteristic spectral intensity sequence and calculates the first derivative, approximate slope, or differential rate of change of its time-varying curve.

[0122] The first derivative can be calculated using continuous derivatives, or obtained by differentiating between adjacent time points, fitting the slope of a sliding window, or taking the derivative after smoothing at multiple points. Its essence lies in characterizing the rate and direction of change of characteristic spectral intensity, rather than focusing solely on the absolute spectral intensity value at a certain moment.

[0123] 9) Simultaneously collect feed gas flow rate and estimate cracking pressurization trend. While acquiring spectral signals in real time, the system continuously acquires the supply flow rate of each feed gas and calculates the total intake flow rate and the feed gas flow rate participating in the cracking.

[0124] For feedstock gases such as methane and ammonia that may undergo cracking or decomposition, leading to an increase in the number of gas moles, the system estimates the equivalent gas increase caused by cracking based on preset cracking gas increase coefficients and current flow rates.

[0125] For example, processes such as methane cracking and ammonia decomposition increase the total number of moles of gas in the system, thus causing additional pressurization. The purpose of this step is to incorporate "feed gas cracking pressurization" as an influencing factor alongside "active metal volatilization pressurization" into the control logic, rather than considering only a single volatilization source.

[0126] 10) Predict the upward trend of air pressure based on the first derivative of characteristic spectral information and the results of cracking and pressurization. The system identifies the volatilization state of active metals based on the magnitude, sign, and duration of the first derivative value of the characteristic spectral information; at the same time, it identifies the degree of pyrolysis pressurization based on the feed gas flow rate, pyrolysis boosting estimation results, and their changing trends.

[0127] When the volatilization of active metals is enhanced, the cracking reaction is enhanced, or both are enhanced simultaneously, the system can determine that the gas pressure inside the furnace has an upward trend and enter different levels of regulation state according to the degree of enhancement.

[0128] 11) Establish a composite control quantity consisting of spectral feedforward, cracking pressurization prediction, and pressure feedback. After the trend judgment result is output, the control system reads the first derivative signal of the characteristic spectrum information as the feedforward input for the volatilization of active metals, and reads the raw material gas flow rate and the estimated amount of cracking pressurization as the additional pressurization input. At the same time, it continuously reads the actual pressure value of the pressure sensor as the feedback input.

[0129] The first derivative of the characteristic spectral information is used to reflect the potential volatile pressurization trend over a future period, the estimated cracking pressurization is used to reflect the potential pressure increase trend caused by the cracking and decomposition of the feed gas, and the pressure feedback value is used to reflect the deviation between the current actual pressure and the target pressure. The control system feeds all of these signals into the control algorithm to form the total control quantity. This avoids the control lag caused by relying solely on the current pressure feedback, and also avoids erroneous adjustments caused by ignoring the intake gas cracking factor based on a single spectral signal.

[0130] 12) The PID control cabinet performs coordinated regulation of the extraction volume and the raw material gas supply volume. The PID control cabinet outputs corresponding control commands based on the composite control quantity. It preferably adjusts the vacuum pump speed by adjusting the frequency of the vacuum pump inverter, thereby continuously adjusting the pumping capacity. If necessary, it can also link with actuators such as proportional regulating valves and pressure regulating valves for auxiliary fine-tuning.

[0131] Meanwhile, when the system detects that cracking or decomposition reactions involving methane, ammonia, or other gases that increase the number of moles of gas are intensified, in addition to increasing the pumping capacity, the total supply flow of the corresponding raw material gas can be reduced simultaneously.

[0132] in: The proportional element is used to respond quickly based on the current pressure deviation; The integral component is used to eliminate long-term deviations and keep the actual air pressure as close as possible to the target setpoint. The differential element is used to suppress rapid fluctuations and reduce overshoot.

[0133] This step not only utilizes the early spectral signals of the local reaction zone to guide the advance adjustment of the overall furnace pressure, but also incorporates the pressure boosting factor of the raw material gas cracking into the control system, simultaneously suppressing the rise in furnace pressure from both the extraction and intake sides.

[0134] 13) Continuous closed-loop correction during operation During the continuous reaction, the system continuously executes the cycle of "spectral acquisition - derivative calculation - cracking pressurization estimation - trend judgment - pressure feedback reading - PID linkage adjustment output" at a set frequency.

[0135] If the volatilization of reactive metals continues to increase, the system maintains a high pumping capacity; if the degree of cracking of the raw material gas increases, the system will appropriately reduce the supply of raw material gas while increasing the pumping capacity; if both types of pressurization factors exist simultaneously, the system will synchronously increase the pumping frequency and reduce the gas supply according to the overall pressurization trend.

[0136] When volatilization or pyrolysis decreases, the system gradually reduces the pumping capacity and restores the supply of raw material gas to prevent over-pumping or excessive reduction of the gas intake from affecting the reaction. If short-term discharge fluctuations, reaction disturbances, or changes in the gas intake occur, the system can synchronously correct the control quantity based on the derivative signal, pyrolysis estimation signal, and pressure deviation signal.

[0137] 14) Abnormal pressure monitoring and safety interlock In addition to normal pressure stabilization control, the system also has a safety threshold judgment logic. When the system detects that the pressure exceeds the safety limit, the rate of pressure rise exceeds the preset limit, or the risk of a rapid rise in furnace pressure is caused by the volatilization of reactive metals and the cracking of raw material gases, the system will immediately trigger an alarm and execute protective actions.

[0138] Protective actions may include: rapidly increasing the output frequency of the vacuum pump inverter, increasing the opening of the proportional valve, reducing or cutting off all raw material gas intake, reducing plasma power, and extinguishing the arc and stopping the machine when necessary.

[0139] 15) Shutdown, evacuation, and reset after the reaction is complete After the reaction is complete, turn off the plasma power supply, stop heating or discharging, shut off the process gas inlet, and keep the pump running for a period of time to extract the residual vapor, reaction gas and pyrolysis products from the furnace. Then, according to the process requirements, refill the furnace with inert gas to atmospheric pressure, open the plasma furnace to collect the material, and finally shut down the PID control cabinet, vacuum pump, vacuum pump frequency converter and related peripheral equipment.

[0140] The control system in this embodiment can not only identify the early signs of disturbance caused by the volatilization of active metals before the overall pressure inside the furnace has increased significantly, but also take into account the pressure increase trend caused by the cracking and decomposition of raw material gas. This improves the completeness of the identification of the source of gas pressure fluctuations inside the furnace and the ability to make early judgments, and reduces the control lag caused by relying solely on pressure feedback.

[0141] The control system in this embodiment can respond in advance to local disturbances caused by the volatilization of reactive metals, predict additional pressurization caused by the cracking and decomposition of raw material gases, and perform closed-loop correction based on actual pressure deviations. This balances the advance, accuracy, and comprehensiveness of control, reduces erroneous adjustments and fluctuations, and improves the stability and reliability of furnace pressure control.

[0142] The control system in this embodiment helps to maintain the furnace pressure more stably within the set range, reducing the impact of gas pressure fluctuations on the discharge state, reaction process, and process parameters. At the same time, it can simultaneously extract gas from the downstream side and introduce gas from the upstream side to suppress pressurization factors, reduce the risk of abnormal pressure rise and overpressure caused by the superposition of active metal volatilization and raw material gas cracking, and improve the safety, stability, and continuous operation capability of the closed plasma high-temperature reaction process.

[0143] In this embodiment, the gas inside the plasma furnace is extracted by a gas extraction device, so that a controlled flow direction and pressure gradient are formed inside the plasma furnace. The vapor and powder products generated by the active metal are drawn away from the high-temperature reaction zone along the predetermined gas exit path under the traction of the outgoing carrier gas, and are continuously collected by the subsequent powder collection chamber, filter or collection cavity, thereby reducing the retention, backflow and random deposition of vapor inside the furnace body, which helps to improve product collection efficiency and process continuity.

[0144] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. 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 dynamic pressure stabilization control method for a closed plasma furnace, wherein a gas extraction device for extracting gas from the furnace is connected to the downstream side of the plasma furnace, and a gas supply device for supplying at least two raw material gases to the furnace is connected to the upstream side of the plasma furnace, characterized in that, The control method includes: Collection furnace Always Lively Metal Based on the characteristic spectral information, the first derivative of the characteristic spectral information is used to calculate... Always Lively Metal Increased gas volume due to enhanced volatility; according to Calculate the equivalent gas increase from cracking by assessing the degree of cracking of all crackable feed gases in the furnace at any given time. Based on the equivalent gas increase from volatilization and the equivalent gas increase from cracking, the total equivalent pressure increase trend in the furnace is calculated. based on The distribution coefficient and total equivalent pressure trend at each moment are used to calculate the equivalent adjustment of downstream side air extraction and upstream side air intake. Based on the equivalent adjustment amount of downstream side air extraction and Calculation of pressure deviation inside the furnace at any time The actual pumping rate of the pumping device is calculated based on the equivalent adjustment amount of the upstream air intake. Total air intake setting at any given time.

2. The dynamic voltage stabilization control method for a closed plasma furnace according to claim 1, characterized in that, Multiply the first derivative of the characteristic spectral information by a coefficient. To obtain active metals Increased gas volume due to enhanced volatility ;in, It is the proportionality coefficient that maps the first derivative of the characteristic spectral information to the volatile equivalent gas increase.

3. The dynamic voltage stabilization control method for a closed plasma furnace according to claim 1, characterized in that, The equivalent gas increase caused by the cracking of all crackable feedstock gases in the furnace at all times Represented as: in, Indicates the gas cracking booster coefficient; Indicates the first The degree of cracking of a type of crackable feedstock gas; Indicates the first A type of crackable feedstock gas in The intake airflow at any given time; This represents the total number of types of crackable feedstock gases.

4. The dynamic voltage stabilization control method for a closed plasma furnace according to claim 3, characterized in that, No. A type of crackable feedstock gas in Fragmentation degree coefficient at time The method of determination is as follows: Get The feedstock gas can be cracked at any time Inlet molar flow rate And detect the crackable raw material gas at the furnace outlet. molar flow rate of pyrolysis gas products Then the raw material gas can be cracked. exist Fragmentation degree coefficient at time Represented as: in, For crackable feedstock gas The cracking reaction formula can crack the raw material gas. molar coefficient, For crackable feedstock gas The molar coefficient of the pyrolysis gas products in the pyrolysis reaction formula.

5. The dynamic voltage stabilization control method for a closed plasma furnace according to claim 1, characterized in that, The equivalent adjustment amount of downstream side air extraction is expressed as: The equivalent regulation of the upstream intake is expressed as: in, This is the adjustment factor for the upstream air intake. For allocation coefficients, This is the equivalent adjustment amount for downstream side air extraction. This is the equivalent adjustment amount of the upstream intake. This represents the total equivalent pressure increase trend within the furnace.

6. The dynamic voltage stabilization control method for a closed plasma furnace according to claim 5, characterized in that, The actual pumping rate of the constant pumping device and Total intake setting at any time They are represented as follows: in, This is the base pumping rate of the pumping device. It is the adjustment coefficient of the pumping rate on the equivalent adjustment amount of the downstream side pumping. This is the pressure feedback correction factor; for Pressure deviation inside the furnace at any given time; It is the reduction coefficient of the equivalent adjustment of the upstream intake to the total intake supply flow rate; This refers to the total supply flow rate of the raw material gas.

7. The dynamic voltage stabilization control method for a closed plasma furnace according to claim 1, characterized in that, The time allocation coefficient is expressed as: in, For allocation coefficients, The pressure sensitivity weight for downstream air extraction. The pressure sensitivity weighting of the upstream crackable feedstock gas. For the equivalent gas increase from pyrolysis, for The first derivative of the time-specific spectral information.

8. A dynamic voltage stabilization control system for a closed plasma furnace, characterized in that, The control system adopts the control method as described in any one of claims 1-7, including a pressure detection device, a plasma furnace, a gas mixing tank, a PID control cabinet, a pyrolysis pressurization detection unit, a characteristic spectral information detection device, a gas extraction device, and a gas supply device. The upstream side of the plasma furnace is connected to a gas supply device via a mixing tank. The gas supply device includes at least two raw material gas supply pipelines. The downstream side of the plasma furnace is connected to an extraction device. The characteristic spectral information detection device collects the characteristic spectral information of active metals in the reaction region of the plasma furnace in real time, and calculates the volatilization equivalent gas increase caused by the enhanced volatilization of active metals based on the first derivative of the characteristic spectral information. The pressure detection device is used to detect the actual pressure inside the plasma furnace in real time. The cracking pressurization detection unit is used to calculate the equivalent gas increase generated by cracking pressurization of all crackable feed gas. The PID control cabinet calculates the equivalent adjustment amount of downstream side air extraction and the equivalent adjustment amount of upstream side air intake based on the allocation coefficient, calculates the actual air extraction rate of the air extraction device based on the equivalent adjustment amount of downstream side air extraction and the pressure deviation in the furnace, and calculates the total air intake setpoint based on the equivalent adjustment amount of upstream side air intake.

9. A dynamic pressure stabilization control method for a closed plasma furnace, wherein a gas extraction device for extracting gas from the furnace is connected to the downstream side of the plasma furnace, and a gas supply device for supplying at least one raw material gas to the furnace is connected to the upstream side of the plasma furnace, characterized in that... The control method includes: Collection furnace Always Lively Metal The characteristic spectral information is used, and the first derivative of the characteristic spectral information is used as a criterion for determining active metals. Basis for the impact of enhanced volatilization on furnace pressure; The pumping device is set based on the first derivative of characteristic spectral information. The theoretical pumping rate at any given time; Get The pressure deviation between the target pressure and the actual pressure inside the furnace at any given time; The theoretical pumping rate of the pumping device is corrected based on the pressure deviation to obtain... The actual pumping rate of the pumping device at all times.

10. A dynamic voltage stabilization control system for a closed plasma furnace, characterized in that, The control system adopts the control method as described in claim 9. The control system includes a pressure detection element, a plasma furnace, a mixing tank, a PID control cabinet, a characteristic spectral information detection device, a gas extraction device, and a gas supply device. The upstream side of the plasma furnace is connected to a gas supply device via a mixing tank. The gas supply device includes at least one raw material gas supply pipeline. The downstream side of the plasma furnace is connected to an extraction device. The characteristic spectral information detection device collects the characteristic spectral information of active metals in the reaction area of ​​the plasma furnace in real time, and judges the degree of enhanced volatilization of active metals based on the first derivative of the characteristic spectral information. The pressure detection device is used to detect the actual pressure inside the plasma furnace in real time. The PID control cabinet calculates the actual pumping rate of the pumping device based on the first derivative of the characteristic spectral information and the pressure deviation inside the furnace.

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