Steam flow control system and control method

Abstract

The application discloses a steam flow control system and a control method. The steam flow control system comprises a steam generator, a water supply module, a proportional adjusting structure, a load end and a control mechanism. The water supply module is connected with the inlet of the steam generator. The outlet of the steam generator is connected with at least one load end through the proportional adjusting structure. A heating module and a pressure sensing structure are arranged in the steam generator. The control mechanism is electrically connected with the proportional adjusting structure, the heating module and the pressure sensing structure respectively. The steam generator is provided with a minimum liquid storage capacity. The steam flow control system has the following advantages: the steam generator is combined with pressure reduction flash evaporation energy compensation, the steam is rapidly and accurately supplied in a multi-loop high dynamic variable load mode, and the volume of the steam generator is optimized. The three advantages are progressive and interact with each other, so that a stable pressure basis is provided for accurate flow regulation.

Description

Technical Field

[0001] This invention relates to the field of industrial production technology, and in particular to a steam flow control system and control method. Background Technology

[0002] In industrial production and testing processes, steam serves as a crucial heat carrier or process medium, and the stability and dynamic regulation of its supply directly impact product quality, testing accuracy, and production efficiency. Existing steam control methods primarily achieve flow control through a closed-loop control mode combining steam generator heating power regulation and proportional valve opening adjustment. While this mode can meet basic requirements under conventional steady-state load scenarios, it exhibits significant technical limitations in scenarios with high dynamic flow rate demands.

[0003] Defect 1: Severe dynamic response lag accompanied by dual risks. The vaporization process of water within the steam generator has inherent thermal inertia. After adjusting the heating power, changes in steam output require a certain heat transfer and vaporization cycle, causing steam output changes to lag behind changes in flow demand. In scenarios such as fuel cell activation testing and sudden load changes in chemical reactions, this lag can reach tens of seconds. This not only fails to quickly match instantaneous load fluctuations but also causes two key problems: First, insufficient vaporization leads to liquid water entrainment in the steam. Liquid water entering the load end (such as fuel cell testing equipment or precision chemical reactors) can cause equipment damage or process failure. Second, insufficient steam output causes a sudden drop in steam generator pressure, leading to significant pressure fluctuations downstream of the pressure reducing valve. This causes the control reference of proportional valves and other regulating valves to shift, further exacerbating flow regulation errors.

[0004] The second defect is insufficient supply stability. Under high dynamic loads, relying solely on conventional adjustments of heating power and proportional valves can easily lead to sudden drops in steam pressure or large fluctuations in flow rate. For example, in the mass production testing of fuel cells, the alternating start-up and shutdown of multiple devices, high-dynamic operating condition simulations, and accelerated endurance testing cause frequent load changes. Traditional control methods can experience pressure shocks, affecting the accuracy of test data.

[0005] Thirdly, the regulation accuracy is limited. Relying solely on closed-loop regulation using proportional valves and flow meters makes it difficult to balance pressure changes and flow demand during sudden load changes, especially in scenarios with large flow rate fluctuations, which can easily lead to overshoot or undershoot. Overshoot or undershoot in steam flow can affect the stability of downstream processes.

[0006] In summary, existing steam control methods are insufficient to address issues such as response lag, poor stability, and inadequate accuracy in high-dynamic-flow-variable scenarios, necessitating a steam control solution with high dynamic response capabilities.

[0007] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0008] The technical problem to be solved by this invention is to address the issues of response lag, poor stability, and insufficient accuracy in high dynamic variable flow steam scenarios.

[0009] The present invention solves the above-mentioned technical problems through the following technical means: This invention claims protection for a steam flow control system, including a steam generator, a water supply module, a proportional control structure, a load terminal, and a control mechanism, wherein the water supply module is connected to the inlet of the steam generator, and the outlet of the steam generator is connected to at least one load terminal through the proportional control structure. The steam generator is equipped with a heating module and a pressure sensing structure. The control mechanism is electrically connected to the proportional control structure, the heating module, and the pressure sensing structure, respectively. The control mechanism is configured to adjust the opening of the proportional control structure based on the steam demand at the load end. When the pressure sensing structure indicates a pressure drop, the steam generator enters the flash evaporation process, increasing the heating power of the heating module to enhance steam generation. When the pressure sensing structure indicates a pressure rise, the heating power of the heating module is reduced, and the steam generator suppresses steam generation. The steam generator is set to a minimum liquid storage capacity, which is set for the flash evaporation process. The pressure drop within the steam generator does not exceed the maximum allowable pressure drop.

[0010] Combining the advantages of steam generator pressure reduction flash evaporation energy replenishment, rapid and precise steam supply under multi-loop high dynamic load changes, and steam generator volume optimization, these three elements work in a progressive and mutually reinforcing manner. This not only enables rapid and precise steam supply during sudden load changes but also allows the flash evaporation-generated steam to quickly fill pressure gaps caused by load shifts, preventing significant pressure drops in the steam generator and maintaining the pressure at the pressure reducing valve inlet pressure within a stable range. This ensures constant pressure at the pressure reducing valve outlet. By combining controllable pressure drop within the steam generator with pressure reduction flash evaporation energy replenishment, this technology solves the problems of pressure fluctuations at the pressure reducing valve outlet pressure and deviations in the control reference of proportional valves and other regulating valves caused by sudden pressure drops in the steam generator, providing a stable pressure foundation for precise flow regulation.

[0011] Preferably, the steam generator is also equipped with a baffle plate, and the heating module, pressure sensing structure and baffle plate are arranged in sequence from bottom to top.

[0012] Baffles are used to guide the flow of high-temperature water, making the steam generation process more uniform.

[0013] Preferably, a demister is also installed inside the steam generator, and the demister is located above the baffle plate.

[0014] The demister separates liquid droplets from the flash steam to prevent liquid water from entering the load end.

[0015] Preferably, a liquid level sensor is also installed inside the steam generator, and the liquid level sensor is located between the pressure sensing structure and the baffle.

[0016] Used to monitor the liquid level inside the steam generator.

[0017] Preferably, the water supply module includes a water source supply, a water replenishment pump, and a check valve. The water source supply is connected to the steam generator inlet through a first pipeline, and the water replenishment pump and the check valve are installed sequentially on the first pipeline.

[0018] The water supply module is used to replenish the water source for the steam generator.

[0019] Preferably, it also includes a pressure reducing valve, with the steam generator outlet connected to one end of a second pipeline, the pressure reducing valve being installed on the second pipeline, and the other end of the second pipeline connected to the load end.

[0020] This invention also claims protection for a steam flow control method employing a steam flow control system, comprising the following steps: Based on the flash evaporation process, the pressure drop in the steam generator does not exceed the maximum allowable pressure drop. Confirm the minimum liquid storage capacity and obtain the steam generator. Start the water supply module to supply water to the steam generator to the predetermined value; Start the heating module to heat the water in the steam generator to the set temperature, and the proportional valve is in the initial state; When the pressure sensor detects a pressure drop, the steam generator enters the flash evaporation process, increasing the heating power of the heating module to increase steam production. When the pressure sensor detects an increase in pressure, it reduces the heating power of the heating module and suppresses steam generation in the steam generator.

[0021] Preferably, confirming the minimum liquid storage capacity of the steam generator includes the following steps: The minimum pressure of the steam generator after the flash process is confirmed by the maximum allowable pressure drop; Confirm the gas production rate of the flash evaporation process within the maximum allowable pressure drop range; Confirm the total amount of steam that the flash evaporation process needs to replenish instantaneously under extreme operating conditions of sudden changes in load demand; Based on the total steam volume and the gas production rate of the flash evaporation process, the minimum liquid storage capacity of the steam generator is determined.

[0022] By clearly defining the maximum allowable pressure drop, the gas production rate of the flash process is calculated backwards. Then, the total amount of steam that the flash process needs to replenish instantaneously under extreme conditions of sudden changes in load demand is calculated. By calculating the gas production rate of the flash process and the total amount of steam required, the minimum liquid storage capacity is calculated. This minimum liquid storage capacity serves as an instantaneous energy reserve source, providing a material basis for steam replenishment when the load changes. This ensures that the reserve capacity can cover the steam demand gap during the heating lag period.

[0023] Preferably, the flash evaporation process includes the following steps: the high-temperature water in the steam generator is depressurized, triggering the flash evaporation process, which is uniformly flashed with the help of baffles, and the generated steam is removed by the demister.

[0024] Preferably, suppressing steam generation includes the following steps: the pressure inside the steam generator increases, the saturation temperature corresponding to the pressure increases, so that the actual water temperature is lower than the current saturation temperature, the water is in a supercooled state, and steam generation is suppressed.

[0025] The advantages of this invention are: it provides dual protection in terms of both gas volume and pressure, effectively compensating for the lag between adjusting the heating power and increasing steam production. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the steam flow control system according to Embodiment 1 of the present invention; Figure 2 This is a schematic flowchart of the steam flow control method according to Embodiment 1 of the present invention; Figure 3 This is a flowchart illustrating the steam generator verification method according to Embodiment 3 of the present invention; Figure 4 This is a schematic diagram of the battery humidification system according to Embodiment 4 of the present invention; 10. Steam generator; 100. Heating module; 101. Pressure sensor; 102. Liquid level sensor; 103. Baffle; 104. Demister; 105. Temperature sensor; 11. Water supply module; 110. Water source supply; 111. Make-up water pump; 113. Check valve; 13. Pressure reducing valve; 130. First steam flow meter; 131. Second steam flow meter; 140. First proportional valve; 141. Second proportional valve; 150. First load end; 151. Second load end; 13 n , No. n Steam flow meter; 14 n , No. n Proportional valve; 15 n , No. n Load end; 16. Controller; 2. Cathode circuit; 3. Anode circuit; 4. Fuel cell stack; 5. Cathode tailpipe unit; 6. Anode tailpipe unit; 7. Control module. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1 See Figure 1 This embodiment requires protection of a steam flow control system for realizing multi-loop steam flow control. The system includes a steam generator 10, a water supply module 11, a pressure reducing valve 13, a steam flow meter, a proportional valve, a load terminal, and a controller 16.

[0029] The water supply module 11 is used to supplement the water source for the steam generator 10. Specifically, the water supply module 11 includes a water supply 110, a water replenishment pump 111 and a one-way valve 113. The water supply 110 is connected to the inlet of the steam generator 10 through a first pipeline. The water replenishment pump 111 and the one-way valve 113 are sequentially installed on the first pipeline.

[0030] The steam generator 10 is a custom-made product. By confirming the minimum liquid storage capacity, the maximum pressure drop is stabilized within the allowable range while achieving flash evaporation. The confirmation of the minimum liquid storage capacity is described in Example 2. The steam generator 10 contains, from bottom to top, a heating module 100, a pressure sensor 101, a liquid level sensor 102, a baffle 103, a demister 104, and a temperature sensor 105. The heating module 100 generates high-temperature water; the pressure sensor 101 monitors the pressure within the steam generator 10; the liquid level sensor 102 monitors the water level; and the baffle 103 guides the flow of high-temperature water, making the steam generation process more uniform and preventing violent gas-liquid phase movement that could cause droplet splashing and liquid inflow into the demister 104. The demister 104 separates droplets from the flash steam, preventing liquid water from entering the load end.

[0031] The outlet of steam generator 10 is connected to one end of a second pipeline. A pressure reducing valve 13 is installed on the second pipeline. The other end of the second pipeline is connected in parallel to one or more load terminals through a corresponding branch. The second pipeline is connected to the first load terminal 150 through a first branch. A first steam flow meter 130 and a first proportional valve 140 are installed on the first branch. The second pipeline is connected to the second load terminal 151 through a second branch. A second steam flow meter 131 and a second proportional valve 141 are installed on the second branch... and so on. n Pipeline passes through the first n Branch connection number n Load side 15 n , No. n The branch road is set up with the first n Steam flow meter 13 n and the n Proportional valve 14 n .

[0032] The controller 16 is electrically connected to the water supply pump 111, the liquid level sensor 102, the temperature sensor 105, the pressure sensor 101, the heating module 100, the steam flow meter, and the proportional valve to form a closed-loop control.

[0033] See Figure 2 The steam flow control system is used to control the steam flow process as follows: S 1. System initialization: Specifically, controller 16 starts water pump 111, which injects water into steam generator 10 via check valve 113. After the water level sensor 102 detects that the water level has reached the preset value, water pump 111 stops. Controller 16 then starts heating module 100, and temperature sensor 105 sends water temperature data back to controller 16. The system continues until the water pressure inside steam generator 10 reaches 6... bar Then, pressure reducing valve 13 adjusts the pressure to 5. bar Each proportional valve is at its initial opening, and the steam flow control system enters standby mode.

[0034] S 2. Changes in steam demand at the load end, with the first... n Load side 15 n For example, the controller receives the first... n load side 15n Changes in steam demand: S 3. When the controller receives the first... n Load side 15 n Increased steam demand triggers flash evaporation within steam generator 10; specifically, controller 16 increases the... n Proportional valve 14 nThe steam flow meter provides real-time feedback on the increase in flow rate, while the pressure sensor 101 detects a decrease in pressure inside the steam generator 10. The high-temperature water inside the steam generator 10 triggers flash evaporation. That is, the high-temperature water inside the steam generator 10 triggers flash evaporation due to the decrease in pressure. The baffle 103 reduces the liquid level fluctuation during flash evaporation, captures splashing droplets, and blocks the gas-liquid surge. The generated steam is deliquescent by the demister 104 and then enters the pipeline through the pressure reducing valve 13 to quickly replenish the steam supply.

[0035] S 4. Power matching: The water pressure inside the steam generator 10 gradually rises and stabilizes at the set value. Specifically, the pressure sensor 101 monitors the pressure inside the generator in real time, and the controller 16 increases the power of the heating module 100 based on the pressure changes. As the heating power increases, the evaporation rate rises, and the pressure inside the steam generator 10 gradually rises. The flashing phenomenon gradually weakens, the steam flow control system switches to stable evaporation steam supply, and the internal pressure of the generator gradually rises and stabilizes at 6... bar The steam flow control system maintains a stable steam supply.

[0036] S 5. When the first n Load side 15 n As steam demand decreases, the steam generator 10 is controlled to suppress steam generation; specifically, the... n Load side 15 n The controller 16 receives the command to reduce the flow rate and then reduces the flow rate of the first controller. n Proportional valve 14 n The flow meter provides real-time feedback on the opening degree of the steam generator 10, indicating a decrease in pressure. Pressure sensor 101 detects an increase in pressure inside the steam generator 10. The increase in pressure corresponds to an increase in saturation temperature. At this time, the actual temperature of the water is lower than the saturation temperature under the new pressure, and the water is in a supercooled state. The evaporation and boiling processes are significantly inhibited, and the steam output automatically decreases, avoiding overpressure or steam waste in the steam flow control system.

[0037] S 6. Pressure sensor 101 detects the rise in pressure inside the generator in real time. The controller reduces the power of heating module 100 to match the steam production with the load demand. As the heating power decreases, the pressure inside the generator drops from a high level and stabilizes at the set value, and the system maintains a stable steam supply.

[0038] It is worth mentioning that, in the above process, the controller 16 starts the water supply pump 111 to supply water to the steam generator 10 based on the data from the liquid level sensor 102, maintaining a stable water level; the flow rate at the remaining load ends is controlled by the... n Steam flow meter and the first n Proportional valve 14 n Closed-loop regulation, unaffected by fluctuations in other loads.

[0039] When all loads stop using steam or total demand drops below the standby threshold, controller 16 will activate each proportional valve 14. n The initial opening is closed, and the power of the heating module 100 is reduced to the standby maintenance power. The steam flow control system then returns to normal. S 1. Standby mode.

[0040] It is worth noting that the load reduction or sudden decrease described above is relative to the values ​​before and after the load change. In actual use, a threshold range can be predetermined to evaluate the rate of load increase and decrease. S 2~ S The description in section 5 is a complete response unit for a single load change. In actual operation, the system will be continuously and cyclically triggered according to specific load requirements. Although the above working process is described using a single load change as an example, the steam flow control method is not limited to flow control for load changes of a single load. Instead, it forms a highly dynamic thermal energy reserve through the flash evaporation process to rapidly supply steam to multiple load ends.

[0041] Furthermore, the load change at the load end is divided into two cases: load surge and load drop. When the load surges, the pressure sensor 101 detects the pressure drop inside the steam generator 10 in real time, and the controller 16 immediately triggers the flash evaporation compensation mechanism. High-temperature water is instantaneously vaporized based on the pressure reduction flash evaporation principle, and the generated supplementary steam is quickly output after demisting treatment, thereby matching the required steam flow increase demand and realizing rapid steam supply.

[0042] When the load suddenly decreases, the pressure sensor 101 detects the upward trend of the system pressure. The controller 16 quickly reduces the power of the heating module 100 to reduce steam generation. On the other hand, the high-temperature water temperature rises due to the pressure increase, and the saturation temperature corresponding to the pressure rises accordingly, so that the actual water temperature is lower than the current saturation temperature. The water is in a supercooled state, thereby inhibiting the evaporation and boiling process, suppressing the generation of excessive steam, avoiding system overpressure and maintaining steam dryness.

[0043] In summary, through controller 16, the... n Proportional valve 14 n The steam flow meter and pressure sensor 101 work together to achieve dynamic switching between flash evaporation and suppression of excessive steam generation; enabling rapid response and allocation of steam demand at multiple load ends.

[0044] Example 2 See Figure 3Based on the rapid steam response process under multi-loop high dynamic load changes in Embodiment 1, this embodiment requires a verification method for protecting the steam generator. By verifying the minimum liquid storage capacity, it ensures that the steam generator 10 has a sufficient amount of high-temperature saturated water. This allows the steam flow control system to achieve rapid steam response under extreme conditions of sudden changes in load demand, while also keeping the pressure drop within the steam generator 10 within an allowable range. This fundamentally solves the inherent contradiction between rapid response and controllable pressure drop in high dynamic steam supply. The verification method includes the following steps: S 9. By allowing the maximum pressure drop Δ P After confirming the flash evaporation process, the minimum pressure of the steam generator 10 is... P 2. Among them, the maximum allowable pressure drop refers to the maximum pressure difference within the steam generator 10 under extreme operating conditions. This is the basis for achieving controllable pressure drop within the steam generator 10. △ P Satisfy the following formula: △P=P1 工作 -P 2 in, P1 工作 The steam generator 10 is in its initial state at the operating pressure.

[0045] S 10. Confirm the gas production rate of the flash process within the maximum allowable pressure drop range. x The core thermodynamic calculations for the flash evaporation process are as follows: Define the initial state, operating pressure of steam generator 10. P1 工作 In the middle, 1 kg The enthalpy of total saturated water is h 1.

[0046] The minimum pressure of steam generator 10 after the flash evaporation process P 2 in, 1 kg Total saturated water will separate into xkg Saturated steam and (1- x ) kg A two-phase mixture of saturated water xkg saturated vapor enthalpy value h 2″, (1- x ) kg Enthalpy of saturated water h 2.

[0047] Since flash evaporation is an adiabatic isenthalpic process, the total heat of the water remains constant before and after the pressure decreases. Therefore: initial total enthalpy = final total enthalpy, which can be expressed by the formula: h 1=x h 2 ″+(1-x) h 2 in, x The flash gas production rate refers to the percentage of gas produced per 1 kg Stored in P1 工作 Saturated water below, when the pressure drops P At 2 o'clock, there will be x The mass is instantly converted into steam.

[0048] S 11. Under extreme operating conditions of sudden changes in load demand, the total amount of steam that needs to be instantly replenished during the flash evaporation process. Ms This includes the following steps: S 110. When the load demand changes abruptly, the controller receives the response and... n The change in the opening degree of the proportional valve yields the steam flow gap Δ required at the load end under extreme operating conditions. Q , △ Q Satisfy the following formula: △ Q = Qmax - Qmin in, Qmax This represents the maximum steam demand required at the load end under extreme operating conditions. Qmin This represents the minimum steam requirement at the load end under extreme operating conditions.

[0049] S 111. Predetermined power lag time t Power lag time refers to the time it takes for the flash evaporation process to be covered.

[0050] S 113 . Calculate the total amount of steam Ms , Ms Satisfy the following formula: Ms =△ Q × t Among them, △ Q This represents the steam flow gap required at the load end under extreme operating conditions.

[0051] S 13. Based on total steam volume Ms Gas production rate during flash evaporation x Confirm the minimum liquid storage capacity of steam generator 10. m , minimum liquid storage volume m This refers to each 1 kgHydropower xkg Steam, so, to produce a total amount of steam... Ms The steam output needs to ensure that the minimum water volume inside the steam generator 10 is greater than a certain amount. Specifically... m Satisfy the following formula: m = Ms / x In this embodiment, by clearly defining the maximum allowable pressure drop, the gas production rate of the flash evaporation process is calculated backwards. Then, the total amount of steam that the flash evaporation process needs to replenish instantaneously under extreme conditions of sudden changes in load demand is calculated. By using the gas production rate of the flash evaporation process and the total amount of steam required, the minimum liquid storage capacity is calculated. This minimum liquid storage capacity serves as an instantaneous energy reserve source, providing a material basis for replenishing steam when the load changes suddenly. This ensures that the reserve capacity can cover the steam demand gap during the heating lag period.

[0052] This embodiment mainly discloses three parts. The first part is the pressure reduction flash evaporation energy replenishment of the steam generator 10. It utilizes the physical property that the saturation temperature of water is positively correlated with the pressure. When the steam load suddenly changes and causes the outlet pressure of the steam generator 10 to drop, the high-temperature water stored in the steam generator 10 will have a higher actual temperature than the saturation temperature under the current pressure due to the sudden pressure drop, thereby rapidly vaporizing to generate steam and realizing the flash evaporation process. This process is fast and effective.

[0053] The second part focuses on rapid and precise steam supply during multi-loop high-dynamic load changes. The steam generator 10 is used for pressure reduction and flash evaporation to supplement energy during multi-loop load changes. Through the interaction of the controller and actuators, the steam supply is precisely maintained, preventing liquid carryover due to insufficient vaporization. The flash evaporation process instantly compensates for steam production gaps caused by heating lag, ensuring real-time matching of steam supply with load demand. This not only avoids insufficient vaporization due to untimely increases in heating power but also prevents unvaporized liquid water from entering subsequent pipelines with the steam, protecting the safety of load-side equipment and process stability. Furthermore, through closed-loop precise adjustment of heating power and the flash evaporation process, it avoids energy waste caused by overheating in traditional systems, saving energy and effectively preventing the risks of overheating and overpressure.

[0054] The third part is the volume optimization of the steam generator 10. That is, by clearly defining the maximum allowable pressure drop, the gas production rate of the flash process is back-calculated, and then the total amount of steam that the flash process needs to replenish instantaneously under extreme conditions of sudden changes in load demand is calculated. By calculating the gas production rate of the flash process and the total amount of steam required, the minimum liquid storage capacity is calculated. This minimum liquid storage capacity serves as an instantaneous energy reserve source, providing a material basis for steam replenishment when the load changes. It ensures that the reserve capacity can cover the steam demand gap during the heating lag period.

[0055] These three elements work in a progressive and interactive manner, enabling rapid and precise steam supply during sudden load changes. Furthermore, the flash-generated steam quickly fills the pressure gap caused by these load shifts, preventing a sharp drop in pressure in the steam generator 10 and maintaining the pressure at the pressure reducing valve inlet within a stable range. This ensures constant pressure at the valve's downstream end. By combining controllable pressure drop within the steam generator 10 with pressure reduction and flash-generated energy replenishment, the problems of pressure fluctuations at the pressure reducing valve outlet and deviations in the control reference of proportional valves and other regulating valves caused by sudden pressure drops in the steam generator 10, as seen in traditional technologies, are solved. This provides a stable pressure basis for precise flow regulation, achieving dual protection in both gas volume and pressure dimensions, effectively compensating for the lag between heating power adjustment and steam production increase.

[0056] Example 3 This embodiment, based on Embodiment 2, provides a specific application of the steam generator 10 verification method, specifically as follows: First, the maximum allowable pressure drop Δ is selected. P It is 0.2 bar Initial state, steam generator 10 operating pressure P1 工作 7 bar The corresponding first water saturation temperature is T 1 is 164.97℃ .

[0057] Based on the formula: △P=P1 工作 -P 2. Obtain the initial state and operating pressure of steam generator 10. P 2 is 6.8 bar The corresponding second water saturation temperature is T 2 is 163.82℃.

[0058] Secondly, the operating pressure of steam generator 10 P1 工作 7 bar In the middle, 1 kg Enthalpy of total saturated water h 1 is 697. kJ / kg .

[0059] The minimum pressure of steam generator 10 after the flash evaporation process P 2 is 6.8 bar , xkg Enthalpy of saturated steam h 2 is 690.8 kJ / kg , xkg saturated vapor enthalpy h 2 ″It is 2760.5 kJ / kg .

[0060] Based on the formula: h 1 =x h 2 ″+(1-x) h 2. The gas production rate of the flash evaporation process can be obtained. x It is 0.305%, which means that every 1 kg Stored in P1 工作 Saturated water below, when the pressure drops P At time 2, 0.305% of the mass will be instantly converted into steam.

[0061] Then, confirm the steam supply range and predict the maximum steam demand required at the load end under extreme operating conditions. Qmax 10 akg / min Minimum steam demand required by the load side before a sudden change in load demand. Qmin for akg / min .

[0062] Based on the formula: △ Q = Qmax - Qmin The steam flow gap Δ under extreme operating conditions was obtained. Q 9 akg / min .

[0063] Predetermined power lag time t 5 s The conversion unit is (5 / 60). min Based on the formula: Ms =△ Q × t The total amount of steam was obtained. Ms =(9 akg / min )×(5 / 60 min )=0.75 akg .

[0064] Finally, based on the formula: m = Ms / x ,calculate m It is 245.9 akg .

[0065] Example 4 See Figure 4The difference between this embodiment and Embodiment 2 lies in two aspects: Difference 1: This embodiment provides a battery humidification system, which uses a steam flow control system to realize the activation test of the fuel cell, ensuring that the cathode and anode gases are supplied under a certain humidity.

[0066] Difference 2: The battery humidification system includes a steam flow control system, cathode circuit 2, anode circuit 3, fuel cell stack 4, cathode temperature control unit, anode temperature control unit, cathode exhaust unit 5, and anode exhaust unit 6. The steam flow control system removes the load end. Cathode circuit 2 is equipped with a cathode flow control unit and a cathode preheating unit. Cathode circuit 2 is used to input air, and the air flow is controlled by the cathode flow control unit. After the cathode preheating unit preheats the air, it is mixed with humidifying steam from the first branch. The cathode temperature control unit adjusts the temperature and humidity of the mixed gas to the target values ​​before it is introduced into the cathode inlet of fuel cell stack 4.

[0067] An anode flow control unit and an anode preheating unit are installed on the anode circuit 3. The anode circuit 3 is used to transport hydrogen. The hydrogen flow control unit controls the hydrogen flow rate. After the anode preheating unit preheats the hydrogen, it is mixed with humidifying steam from the second branch. The anode temperature control unit adjusts the temperature and humidity of the mixed gas to the target value before it is introduced into the anode inlet of the fuel cell stack 4.

[0068] The fuel cell stack 4 receives and processes the above-mentioned gases and carries out a chemical reaction. After the reaction, the cathode tail gas is processed by the cathode tail gas unit 5 and the anode tail gas is processed by the anode tail gas unit 6.

[0069] Difference 3: In the steam flow control system, controller 16 is replaced by control module 7. Control module 7 is electrically connected to anode flow control unit, cathode flow control unit, water supply pump 111, liquid level sensor 102, temperature sensor 105, pressure sensor 101, heating module 100, steam flow meter and proportional valve to form a closed-loop control.

[0070] In this embodiment, the steam generator 10 is integrated with pressure reduction flash evaporation for energy replenishment, rapid and precise steam supply under multi-loop high dynamic load changes, and volume optimization of the steam generator 10 into the battery humidification system. This addresses the problem of excessive dryness or wetness in the fuel cell stack 4 caused by insufficient response speed and stability in traditional control methods, particularly in high-dynamic scenarios such as fuel cell durability testing and multi-device batch testing. By achieving rapid steam response and precise steam supply, this embodiment ensures the long-term operational stability of the fuel cell stack 4 under high-dynamic conditions, overcoming the limitations of traditional methods that cannot meet the requirements of long-term dynamic testing or multi-device collaborative operation, thus restricting their application scope.

[0071] The stable operation process of this battery humidification system is as follows: S13. The battery humidification system starts idling at initial speed, specifically including the following steps: S130. The steam flow control system enters standby mode, meaning that the load demand changes little. Refer to S1 for further details.

[0072] S131. The cathode flow control unit controls the first flow of air to be input from the cathode circuit 2. After the air is preheated by the cathode preheating unit, it is mixed with the first flow of steam from the first branch. The cathode temperature control unit adjusts the temperature and humidity of the mixed gas to the target value before it is introduced into the cathode inlet of the fuel cell stack 4.

[0073] S132. The anode flow control unit controls the first flow of hydrogen to be input from the anode circuit 3. After the hydrogen is preheated by the anode preheating unit, it is mixed with the first flow of steam from the second branch. The anode temperature control unit adjusts the temperature and humidity of the mixed gas to the target value before it is introduced into the anode inlet of the fuel cell stack 4.

[0074] S133. The fuel cell stack 4 receives and processes the above-mentioned gas and performs a chemical reaction. After the reaction, the cathode tail gas is processed by the cathode tail gas unit 5 and the anode tail gas is processed by the anode tail gas unit 6.

[0075] S14. High dynamic load response stage of battery humidification system, specifically including the following steps: S140. The hydrogen flow rate input from the anode circuit 3 and the air flow rate input from the cathode circuit 2 increase to the second flow rate. The steam flow control system enters the second flow rate steam supply stage. Refer to S2, which will not be repeated here. The steam generator 10 flashes and quickly replenishes the two steam circuits to avoid steam supply lag, which could lead to the fuel cell stack 4 becoming too dry.

[0076] S141. The second flow of air is input from the cathode circuit 2. After the air is preheated by the cathode preheating unit, it is mixed with the second flow of steam from the first branch. The temperature and humidity of the mixed gas are adjusted to the target value by the cathode temperature control unit and then introduced into the cathode inlet of the fuel cell stack 4.

[0077] S142. The second flow of hydrogen is input from the anode circuit 3. After the hydrogen is preheated by the anode preheating unit, it is mixed with the second flow of steam from the second branch. The temperature and humidity of the mixed gas are adjusted to the target value by the anode temperature control unit and then introduced into the anode inlet of the fuel cell stack 4.

[0078] S143. The fuel cell stack 4 receives and processes the above-mentioned gas and performs a chemical reaction. After the reaction, the cathode tail gas is processed by the cathode tail gas unit 5 and the anode tail gas is processed by the anode tail gas unit 6.

[0079] S15. The battery humidification system is in a stable full-load operation phase, which specifically includes the following steps: S150. Steam supply of the steam flow control system returns to stability. Specifically, the power of the heating module 100 gradually catches up with the steam consumption, the flash effect weakens, and the steam pressure and output return to stability. See S3. Based on feedback from the liquid level sensor 102, the controller 16 starts the water replenishment pump 111 to perform closed-loop water replenishment in order to maintain a stable water level in the steam generator 10.

[0080] S151. The anode circuit 3 and the cathode circuit 2 maintain a constant full-load gas flow rate and continuously supply the fuel cell stack 4. The fuel cell stack 4 operates at full load. The anode tailpipe unit 6 and the cathode tailpipe unit 5 work in coordination and maintain their respective circuit back pressure stability.

[0081] S16. The battery humidification system's load shedding phase includes the following steps: S160. The hydrogen flow rate input from the anode circuit 3 and the air flow rate input from the cathode circuit 2 are reduced, and the steam flow control system enters the first flow rate steam supply stage. See S4 for details. Steam generation is suppressed by the steam generator 10 to avoid the problem of excessive moisture in the fuel cell stack 4.

[0082] S161. The first flow of air is input from the cathode circuit 2. After the air is preheated by the cathode preheating unit, it is mixed with the first flow of steam from the first branch. The temperature and humidity of the mixed gas are adjusted to the target value by the cathode temperature control unit and then introduced into the cathode inlet of the fuel cell stack 4.

[0083] S162. The first flow of hydrogen is input from the anode circuit 3. After the hydrogen is preheated by the anode preheating unit, it is mixed with the first flow of steam from the second branch. The temperature and humidity of the mixed gas are adjusted to the target value by the anode temperature control unit and then introduced into the anode inlet of the fuel cell stack 4.

[0084] S163. The fuel cell stack 4 receives and processes the above-mentioned gas and performs a chemical reaction. After the reaction, the cathode tail gas is processed by the cathode tail gas unit 5 and the anode tail gas is processed by the anode tail gas unit 6.

[0085] It is worth mentioning that the first flow rate and the second flow rate can be defined based on the actual operating conditions, with the first flow rate being less than the second flow rate.

[0086] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A steam flow control system, characterized in that, It includes a steam generator (10), a water supply module (11), a proportional control structure, a load end and a control mechanism. The water supply module (11) is connected to the inlet of the steam generator (10), and the outlet of the steam generator (10) is connected to at least one load end through the proportional control structure. The steam generator (10) is equipped with a heating module (100) and a pressure sensing structure. The control mechanism is electrically connected to the proportional adjustment structure, the heating module (100) and the pressure sensing structure respectively. The control mechanism is configured to adjust the opening of the proportional adjustment structure based on the steam demand at the load end. When the pressure sensor determines that the pressure has dropped, the steam generator (10) enters the flash steaming process and increases the heating power of the heating module (100) to increase the steam generation process. When the pressure sensor determines that the pressure has risen, the heating power of the heating module (100) is reduced and the steam generator (10) suppresses steam generation. The steam generator (10) is set to a minimum liquid storage capacity, which is set to a flash evaporation process. The pressure drop in the steam generator (10) does not exceed the maximum allowable pressure drop.

2. The steam flow control system according to claim 1, characterized in that, The steam generator (10) is also equipped with a baffle (103), and the heating module (100), pressure sensing structure and baffle (103) are arranged from bottom to top.

3. The steam flow control system according to claim 2, characterized in that, A demister (104) is also installed inside the steam generator (10), and the demister (104) is located above the baffle (103).

4. The steam flow control system according to claim 2, characterized in that, A liquid level sensor (102) is also installed inside the steam generator (10), which is located between the pressure sensing structure and the baffle (103).

5. The steam flow control system according to claim 1, characterized in that, The water supply module (11) includes a water supply (110), a water replenishment pump (111) and a check valve (113). The water supply (110) is connected to the inlet of the steam generator (10) through a first pipeline. The water replenishment pump (111) and the check valve (113) are installed in sequence on the first pipeline.

6. The steam flow control system according to any one of claims 1 to 5, characterized in that, It also includes a pressure reducing valve (13), the outlet of the steam generator (10) is connected to one end of the second pipeline, the pressure reducing valve (13) is installed on the second pipeline, and the other end of the second pipeline is connected to the load end.

7. A steam flow control method employing the steam flow control system according to any one of claims 1 to 6, characterized in that, Includes the following steps: Based on the flash evaporation process, the pressure drop in the steam generator (10) does not exceed the maximum allowable pressure drop. Confirm the minimum liquid storage volume and obtain the steam generator (10). Start the water supply module (11) to supply water to the steam generator (10) to the predetermined value; Start the heating module (100) to heat the water in the steam generator (10) to the set temperature, and the proportional valve is in the initial state; Based on the signal judgment of the pressure sensing structure, the pressure drops, the steam generator (10) enters the flash steaming process, and the heating power of the heating module (100) is increased to increase the steam generation process; Based on the signal judgment of the pressure sensing structure, the pressure rises, the heating power of the heating module (100) is reduced, and the steam generator (10) suppresses steam generation.

8. The steam flow control method according to claim 7, characterized in that, Confirming the minimum liquid storage capacity of the steam generator (10) includes the following steps: The minimum pressure of the steam generator (10) was determined by allowing the maximum pressure drop during the flash process. Confirm the gas production rate of the flash evaporation process within the maximum allowable pressure drop range; Confirm the total amount of steam that the flash evaporation process needs to replenish instantaneously under extreme operating conditions of sudden changes in load demand; Based on the total steam volume and the gas production rate of the flash evaporation process, the minimum liquid storage capacity of the steam generator (10) is determined.

9. The steam flow control method according to claim 7, characterized in that, The flash evaporation process includes the following steps: the high-temperature water in the steam generator (10) is depressurized, triggering the flash evaporation process. It is uniformly flashed with the help of the baffle (103) to generate steam, which is then removed by the demister (104).

10. The steam flow control method according to claim 1, characterized in that, Suppressing steam generation includes the following steps: the pressure inside the steam generator (10) rises, the saturation temperature corresponding to the pressure rises, so that the actual water temperature is lower than the current saturation temperature, the water is in a supercooled state, and steam generation is suppressed.

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