Gas mixing device for multi-fuel blending combustion and control method thereof

Abstract

The invention discloses a gas mixing device for multi-fuel blending combustion and a control method of the gas mixing device. The gas mixing device comprises a gas mixing tank body, four gas inlet pipelines, a gas outlet pipeline and a programmable logic controller control system, and the four gas inlet pipelines are used for inputting hydrogen, ammonia gas, natural gas and air respectively; an inlet of the gas mixing tank body is connected with outlets of the gas inlet pipelines, and the gas mixing tank body is provided with a gas mixing tank pressure sensor and a safety valve; the gas outlet pipeline is used for conveying the mixed gas to the combustion nozzle and is provided with a second electric valve and a second flow meter; the control system comprises a programmable logic controller and a human-computer interface, and the four gas inlet pipelines and the gas mixing tank are arranged, so that controllable mixing of two or more of hydrogen, ammonia gas, natural gas and air is realized, mixing combustion of different fuels (hydrogen, ammonia gas and natural gas) in different proportions can be realized, and combustion of different fuels (hydrogen, ammonia gas and natural gas) in different proportions can be realized. And accurate control over the ratio of fuel to air in the premixed combustion mode can be achieved.

Description

Technical Field

[0001] This invention relates to the field of fuel combustion and gas mixing control technology, specifically a gas mixing device and its control method for the combustion of multiple fuels. Background Technology

[0002] Existing mixed-fuel and premixed combustion technologies primarily rely on mixing a single fuel (such as natural gas or hydrogen) with air. Their system designs generally suffer from the following drawbacks: First, the structures are complex, often relying on multi-stage injectors or multi-channel regulating valves, leading to excessively high manufacturing and maintenance costs and hindering widespread application. Second, mixing accuracy is insufficient; fuel ratio control depends on simple mechanical valves or single-point flow measurements, making it difficult to achieve stable proportions of multiple fuels (hydrogen, ammonia, natural gas) under different operating conditions. Third, the lack of dedicated tanks for thorough mixing results in poor mixing uniformity, limited combustion efficiency, and in some cases, incomplete combustion and excessive local emissions. Finally, existing systems generally lack deep integration with programmable logic controllers or digital control systems, failing to dynamically adjust based on real-time parameters such as upstream pressure and flow, resulting in insufficient application flexibility and intelligence. In summary, existing technologies struggle to simultaneously meet the comprehensive requirements of structural simplification, cost reduction, improved mixing accuracy, and optimized premixed combustion. Summary of the Invention The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention provides a gas mixing device and its control method for the combustion of multiple fuels.

[0003] According to an embodiment of the present invention, a gas mixing device for multi-fuel blending and combustion includes a mixing tank, four inlet pipes, an outlet pipe, and a programmable logic controller (PLC) control system. The four inlet pipes are respectively used for the input of hydrogen, ammonia, natural gas, and air. Each inlet pipe is equipped with a first electric valve, a first flow meter, and a first pressure sensor at its front end. The inlet of the mixing tank is connected to the outlet of each of the inlet pipes. The mixing tank contains internal components for promoting turbulent gas mixing, and includes a mixing tank pressure sensor and a safety valve. The outlet pipe is used to deliver the mixed gas to the combustion nozzle, and includes a second electric valve and a second flow meter. The control system includes a PLC and... The human-machine interface (HMI) is connected to the programmable logic controller (PLC) of each electric valve, flow meter, and pressure sensor for real-time acquisition of flow and pressure data and control of valve opening. The control system is configured to perform the following steps: system initialization and self-test; receiving the operating mode selected by the operator through the HMI; real-time acquisition and display of flow and pressure in each pipeline and mixing tank pressure; calculation of the initial valve opening based on the set target mixing ratio and outlet flow rate, and issuance of control signals; closed-loop adjustment based on flow feedback to bring the actual mixing ratio closer to the target value; installation of an outlet flow meter at the mixing tank outlet to adjust the outlet valve according to combustion requirements; and execution of safety protection logic when pressure or flow exceeds limits.

[0004] A gas mixing device for multi-fuel co-combustion according to an embodiment of the present invention has at least the following beneficial effects: This invention, through the installation of four intake pipes and a mixing tank, enables controllable mixing of two or more gases (hydrogen, ammonia, natural gas, and air). It allows for the blending and combustion of different fuels (hydrogen, ammonia, and natural gas) in varying proportions, as well as precise control of the fuel-air ratio in a premixed combustion mode. This effectively reduces emissions of carbon oxides and other pollutants during combustion and creates a homogeneous gas mixture before combustion, significantly improving combustion efficiency and stability. The system, by installing a first flow meter, a first pressure sensor, and a first electric valve before each intake pipe, combined with a programmable logic controller (PLC) and other digital control systems, achieves real-time acquisition and intelligent adjustment of gas flow and pressure. The valve opening can be dynamically adjusted based on fluctuations in upstream gas source pressure, load changes, or the target mixing ratio, thereby ensuring mixing accuracy and fuel utilization efficiency.

[0005] According to an embodiment of the present invention, a gas mixing device control method is applied to the gas mixing device described above, and the gas mixing device control method includes: System initialization steps: Perform a power-on self-test of the programmable logic controller (PLC) and receive the operating mode selected by the operator through the human-machine interface; Data acquisition and display steps: Continuously acquire the pressure and instantaneous flow rate of each intake pipeline, the pressure in the mixing tank and the outlet flow rate, and display and record them in real time; Target setting steps: Receive the target mixing ratio and target outlet flow rate settings; Valve control steps: Based on the target mixing ratio, target outlet flow rate, and current pressure of each gas source, calculate and execute the initial opening of each inlet pipeline valve; subsequently, based on the feedback signal from the flow meter, fine-tune the valve opening through a closed-loop control algorithm to make the actual gas mixing ratio approach the target mixing ratio; Safety monitoring steps: Monitor system pressure and flow in real time. If any parameter is found to be out of limit, execute safety protection logic and prioritize shutting off the fuel intake valve.

[0006] According to some embodiments of the present invention, the operating modes include a pure fuel mixing mode, an air premixing mode, a manual mode, and a maintenance mode; in the air premixing mode, the valve control step simultaneously calculates and controls the valve opening of the air pipeline.

[0007] According to some embodiments of the present invention, the calculation of the initial opening of each intake pipeline valve specifically involves: calling a pre-stored valve characteristic model or looking up a table, and calculating the initial opening by combining the current supply pressure and the target flow rate; the gas mixing device control method further includes: periodically or when the calibration condition is triggered, updating the valve characteristic model based on the current pressure difference, valve opening and corresponding flow data.

[0008] According to some embodiments of the present invention, the closed-loop control algorithm is PID control, lookup table control, or model predictive control; the gas mixing device control method further includes a PID parameter adaptive step: automatically adjusting the proportional, integral, and derivative parameters of the PID controller according to the response performance of the closed-loop system.

[0009] According to some embodiments of the present invention, the gas mixing device control method further includes a working condition switching step: when the working mode or target ratio is switched, the system oscillation is avoided by limiting the rate of change or gradually adjusting the tank outlet flow rate.

[0010] According to some embodiments of the present invention, the valve control step further includes a steady-state judgment step: during the fine-tuning of the valve opening, the fluctuation rate of the mixing ratio and the tank outlet flow rate is monitored, and when the fluctuation rate is lower than a preset threshold, the system is determined to have entered a steady state.

[0011] According to some embodiments of the present invention, the data recording and optimization steps include: recording key operating data including pressure, flow rate, valve opening degree, valve characteristic model version, and alarm events; optimizing the control model offline based on historical data and sending the optimized strategy to the control system.

[0012] According to some embodiments of the present invention, the safety protection logic includes: closing the corresponding fuel intake valve, opening the safety valve or bypass valve, recording the alarm event, and switching to a safe shutdown or lowest risk operation mode.

[0013] According to some embodiments of the present invention, the gas mixing device control method further includes a safe shutdown step: closing all fuel inlet valves in a predefined sequence, performing air purging, opening the safety valve to release the pressure inside the tank to a safe range, and disconnecting the power after confirming that all valves are in a safe position.

[0014] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic diagram of a gas mixing device for the combustion of multiple fuels. Figure 2 This is a flowchart of a gas mixing device for the combustion of multiple fuels. Figure 3 This is a flowchart illustrating the control method for a gas mixing device. Figure 4 A schematic diagram of the mixing tank structure of a gas mixing device for multi-fuel co-combustion; Icon labels: Mixing tank body 100, mixing tank pressure sensor 110, safety valve 120, central impact cone 130, turbulence generator 140, honeycomb rectifier grid 150, metal porous flow equalization plate 160, air inlet pipe 200, pressure reducing valve 210, ball valve 220, first pressure gauge 230, first solenoid valve 240, first flow meter 250, air outlet pipe 300, mixing outlet 301, second flow meter 310, second solenoid valve 320, shut-off valve 330, control system 400, programmable logic controller 410, human-machine interface 420. Detailed Implementation

[0016] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0017] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0018] In the description of this invention, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features or their sequential relationship.

[0019] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0020] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are some embodiments of the present invention, not all embodiments.

[0021] To address the problems of existing mixed-fuel and premixed combustion technologies, such as complex structure, high manufacturing and maintenance costs, insufficient mixing precision, lack of dedicated tanks for thorough mixing, and limited control methods that hinder multi-fuel compatibility and dynamic adjustment, this paper provides a gas mixing device and its control method for multi-fuel blending combustion. This gas mixing device enables flexible mixing of hydrogen, ammonia, natural gas, and air, reducing carbon emissions while improving gas mixing uniformity and combustion stability. Furthermore, by introducing digital control methods such as PLCs, it achieves real-time adjustment based on upstream pressure, flow rate, and valve opening, thus balancing the requirements of simplified system design, low-cost operation, and high-precision control.

[0022] Reference Figure 1A gas mixing device for multi-fuel blending and combustion includes a mixing tank 100, four inlet pipes 200, an outlet pipe 300, a programmable logic controller 410, and a control system 400. The four inlet pipes 200 are respectively used for the input of hydrogen, ammonia, natural gas, and air. Each inlet pipe is equipped with a first electric valve, a first flow meter 250, and a first pressure sensor at its front end for real-time adjustment and monitoring of gas flow and pressure. Each inlet pipe is connected to the inlet of the mixing tank 100. Specifically, the first electric valve includes a pressure reducing valve 210, a ball valve 220, and a first solenoid valve 240. The first pressure sensor includes a first pressure gauge 230. Each inlet pipe is equipped with a pressure reducing valve 210, a ball valve 220, a first flow meter 250, a first pressure gauge 230, and a first solenoid valve 240 sequentially from upstream to downstream. The electric regulating valve can also be a pneumatic butterfly valve. In some other embodiments, the ball valve 220 can be a regular manual ball valve 220. Of course, in this embodiment, an electrically operated ball valve 220 can be used, which is controlled by the programmable logic controller 410 to open and close.

[0023] The mixing tank 100 contains internal components designed to promote turbulent gas mixing. These components include specialized baffles and airflow channels, which generate turbulence to facilitate rapid and uniform mixing of different gases, rather than simple laminar diffusion. The mixing tank 100 achieves thorough mixing of multiple gases through turbulent disturbance and diffusion, forming a homogeneous gas mixture. The internal design of the mixing tank 100 fully utilizes turbulent diffusion to ensure more uniform gas mixing, reducing the risk of incomplete combustion and deflagration. The mixing tank 100 is equipped with a mixing tank pressure sensor 110 and a safety valve 120. The internal components can be optimized based on experiments or computational fluid dynamics simulations to improve the volume and flow channel shape of the mixing tank 100, further enhancing gas uniformity and combustion stability.

[0024] The gas outlet line 300 is used to deliver the mixed gas to the combustion nozzle. The gas outlet line 300 is equipped with a second electric valve and a second flow meter 310 to monitor the state of the mixed gas delivered to the combustion chamber.

[0025] The gas outlet pipeline 300 is used to deliver the mixed gas to the combustion nozzle. The gas outlet pipeline 300 is equipped with a second electric valve and a second flow meter 310. The second electric valve includes a second solenoid valve 320 and a shut-off valve 330. The gas outlet pipeline 300 is equipped with a mixed gas outlet 301. The control system 400 includes a programmable logic controller 410 and a human-machine interface 420. The programmable logic controller 410 is connected to each electric valve, flow meter and pressure sensor to collect flow and pressure data in real time and control the opening degree of each valve. The control system 400 is configured to perform the following steps: System initialization and self-test, receiving the working mode selected by the operator through the human-machine interface 420; Real-time data collection and display of flow rate, pressure in each pipeline and pressure in the mixing tank; Based on the set target mixing ratio and outlet flow rate, calculate the initial opening degree of each valve and send control signals; Closed-loop adjustment based on flow feedback is used to bring the actual mixing ratio closer to the target value; An outlet gas flow meter is installed at the outlet of the mixing tank, and the outlet gas valve is adjusted according to the combustion end demand. Execute safety protection logic when pressure or flow exceeds limits.

[0026] This invention, through the installation of four intake pipes 200 and a mixing tank 100, enables controllable mixing of two or more gases (hydrogen, ammonia, natural gas, and air). It allows for the blending and combustion of different fuels (hydrogen, ammonia, and natural gas) in varying proportions, as well as precise control of the fuel-air ratio in premixed combustion mode. This effectively reduces emissions of carbon oxides and other pollutants during combustion and creates a uniform gas mixture before combustion, significantly improving combustion efficiency and stability. The system, by installing a first flow meter, a first pressure sensor, and a first electric valve before each intake pipe, combined with a digital control system 400 including a programmable logic controller 410, achieves real-time acquisition and intelligent adjustment of gas flow and pressure. The valve opening can be dynamically adjusted based on fluctuations in upstream gas source pressure, load changes, or the target mixing ratio, thereby ensuring mixing accuracy and fuel utilization efficiency. The internal design of the mixing tank 100 fully utilizes turbulent diffusion to ensure more uniform gas mixing and reduce the risk of incomplete combustion and deflagration. Meanwhile, the entire device of this invention adopts a modular design, which is simple in structure, easy to manufacture and maintain, and has a low cost. It is suitable for low-carbon clean combustion under multiple working conditions and can be widely used in gas engines, industrial burners and other combustion systems to achieve a dual improvement in environmental benefits and energy utilization efficiency.

[0027] For details on the principle of the gas mixing device, please refer to [link / reference]. Figure 2 As shown, specifically: After the system is powered on, the programmable logic controller 410 first executes an initialization self-test process: sequentially checking whether the signals of each flow meter, pressure gauge, and other sensor are normal, whether each valve and other actuator can operate normally, and whether the reading of the mixing tank pressure sensor 110 is within the safe range. The self-test results are displayed in real time on the human-machine interface 420. If any self-test item fails, the system will issue an audible and visual alarm and lock the main valve in a state where it is prohibited from opening to ensure safety. After the self-test passes, the operator can select the working mode on the human-machine interface 420, such as "pure fuel mixing mode" (only adjusting the ratio of hydrogen, ammonia, and natural gas to achieve carbon reduction) or "air premixing mode" (introducing air in proportion while mixing fuel to form a premixed gas that can be directly combusted).

[0028] After the system is running, the programmable logic controller 410 continuously collects the pressure, instantaneous flow rate, pressure in the mixing tank, and outlet flow rate of each intake pipeline. All of these data are displayed in real time on the human-machine interface 420 in the form of trend charts and numbers, and stored in the historical database.

[0029] Once the operator sets the target, such as a mixing ratio of 50% hydrogen, 30% ammonia, and 20% natural gas, and a total outlet flow rate of 10 standard cubic meters per minute, the control process officially begins. The programmable logic controller (PLC) 410 does not directly perform trial-and-error PID control; instead, it first calls its internally stored valve characteristic model. This model is a library of "valve opening-pressure-flow" relationship curves built based on historical data. The PLC 410, combining the current supply pressure of each gas source and the target flow rate, calculates the initial opening of each valve required to achieve the target ratio and sends this signal to each electrically controlled regulating valve. The valves are then rapidly driven to the designated position.

[0030] After the valves are activated, the flow meters in each pipeline report the actual flow rate. The programmable logic controller 410 compares the actual flow rate with the target flow rate. If an error exists, a closed-loop control algorithm is activated for fine-tuning. In this embodiment, PID control is used for precise flow rate locking. Simultaneously, the system monitors the stability of the mixing ratio. When the fluctuation rate of each flow rate is lower than a preset threshold for a period of time, the system is determined to have entered steady-state operation.

[0031] To ensure long-term control accuracy, the system possesses adaptive learning capabilities. The programmable logic controller (PLC) 410 periodically executes a valve characteristic generation process, for example, every eight hours of operation or when a significant change in supply pressure is detected. It collects data on valve opening, upstream and downstream pressure difference, and actual flow rate over a given period, using this new data to update the existing valve characteristic model, enabling the model to adapt to valve wear or changes in pipeline characteristics. Furthermore, after valve characteristic updates or when the system's dynamic response slows down, the PLC 410 also initiates a PID parameter self-tuning algorithm. Based on performance indicators such as system overshoot and settling time, it automatically adjusts the proportional, integral, and derivative parameters of the PID controller to maintain optimal control response. In this embodiment, the control program has a PID closed-loop regulation function, which can automatically adjust the PID parameters, including proportional, integral, and derivative coefficients, based on the valve flow output and real-time gas mixing ratio to optimize response speed and control accuracy.

[0032] When switching operating conditions is required, such as from a high hydrogen ratio to a high ammonia ratio, the programmable logic controller 410 will activate a smooth transition strategy. It will not immediately change the target setpoint, but will gradually adjust the target flow rate of each pipeline at a limited and gradual rate, and prioritize stabilizing the outlet pressure of the mixing tank, thereby effectively avoiding drastic fluctuations in flow rate and pressure and ensuring the continuous stability of the downstream combustion process.

[0033] Safety logic is implemented throughout the process. If any sensor reading exceeds the limit, such as the mixing tank pressure exceeding the safety threshold or the detected flow rate ratio deviating significantly from the set value, the programmable logic controller 410 will immediately trigger the highest priority safety procedure. This procedure follows a predefined safety sequence, first quickly closing all fuel inlet valves, then opening the safety relief valve or initiating the nitrogen purging line as needed, while simultaneously recording alarm events and notifying the operator.

[0034] Finally, all operating parameters, including pressure, flow rate, valve opening, adaptive model version, alarm records, etc., are recorded in detail. This data can be used for offline analysis to further optimize the valve characteristic model, and even train a more advanced model predictive controller. The optimized new strategy is then sent to the programmable logic controller 410 to achieve continuous self-optimization of the system.

[0035] Furthermore, in this embodiment, the mixing tank 100 is a horizontal cylindrical shape made of hydrogen-resistant stainless steel. The left end cap of the tank has four tangential air inlets, corresponding to hydrogen, ammonia, natural gas, and air pipelines, respectively. After the gas enters tangentially, a strong swirling field is formed at the front end of the tank, completing the initial macroscopic mixing.

[0036] Reference Figure 4At the center of the mixing tank 100, a streamlined central impact cone 130 is fixedly installed. Four tangentially entering rotating airflows collide with each other at the center of the mixing tank 100 and impact the central impact cone 130. The airflows are violently sheared and broken up, generating a large number of small-scale vortices, achieving secondary enhanced mixing. Downstream of the central impact cone 130, three layers of static mixing modules are fixedly installed on the inner wall of the mixing tank 100. The first layer is an "S"-shaped channel turbulence generator 140, used to further turbulentize the airflow; the second layer is a honeycomb-shaped flow straightener 150, which sorts the turbulence into orderly fine streams; the last layer is a sintered metal porous flow equalization plate 160, with an average pore diameter of 0.5 mm, which can divide the airflow into countless tiny jets, ultimately achieving sufficient diffusion and mixing at the molecular level, forming a relatively uniform gas mixture. The tail base of the central impact cone 130 partially overlaps axially with the starting end of the turbulence generator 140 in the "S"-shaped channel, thus forming a flow field coupling zone between them. This design allows the large-scale vortices generated by the impact cone to be captured and refined by the downstream static mixing module before they decay, achieving efficient integration of macroscopic eddy mixing and microscopic turbulent diffusion, significantly improving mixing uniformity and energy utilization efficiency.

[0037] The homogenized gas mixture flows out from the outlet in the middle of the right end cap of the tank. Inside this outlet, a wire mesh flame arrester is integrated to prevent downstream backfire. A pressure sensor 110 and a temperature sensor interface are respectively installed at the top and bottom of the tank for real-time monitoring of the tank's internal conditions.

[0038] Furthermore, a secondary premixing structure is incorporated, comprising annularly distributed guide vanes and a centrally located swirl core. This structure further promotes uniform mixing of the gas mixture and enhances flow stability. The gap between the guide vanes and the swirl core forms a shear turbulence zone, effectively breaking up gas stratification. A second flow meter 310 monitors the outlet gas flow rate in real time, and a programmable logic controller 410 controls the system 400 to dynamically adjust the opening of the second electric valve based on feedback signals, ensuring precise and controllable output ratio of the mixed gas.

[0039] Furthermore, temperature sensors and auxiliary mixing pipelines are added to further improve mixing accuracy and combustion efficiency. The mixed gas produced by this device can be used in gas engines, industrial burners, or other combustion devices to achieve low-carbon, clean, and efficient combustion, balancing environmental protection and energy utilization efficiency.

[0040] The present invention also provides an embodiment of a control method for a gas mixing device, referring to... Figure 3 The gas mixing device control method is applied to the aforementioned gas mixing device, and the gas mixing device control method includes: Step S100 System initialization step: The programmable logic controller 410 performs a power-on self-test of the control system 400 and receives the operating mode selected by the operator through the human-machine interface 420; Step S200 Data Acquisition and Display: Continuously acquire the pressure and instantaneous flow rate of each intake pipeline, the pressure in the mixing tank and the outlet flow rate, and display and record them in real time; Step S300 Target Setting Step: Receive the target mixing ratio and target outlet flow rate settings; Step S400 Valve Control Steps: Based on the target mixing ratio, target outlet flow rate, and current pressure of each gas source, calculate and execute the initial opening degree of each inlet pipeline valve; subsequently, based on the feedback signal from the flow meter, fine-tune the valve opening degree through a closed-loop control algorithm to make the actual gas mixing ratio approach the target mixing ratio; Step S500 Safety Monitoring Step: Monitor system pressure and flow in real time. If any parameter is found to be out of limit, execute safety protection logic and prioritize closing the fuel intake valve.

[0041] In step S100, the operating modes include pure fuel mixing mode, air premixing mode, manual mode, and maintenance mode; in air premixing mode, the valve control step simultaneously calculates and controls the valve opening of the air pipeline.

[0042] In step S400, the initial opening degree of each intake pipeline valve is calculated. Specifically, the initial opening degree is calculated by calling the pre-stored valve characteristic model or looking up a table, and combining the current supply pressure and the target flow rate. The gas mixing device control method also includes updating the valve characteristic model periodically or when the calibration condition is triggered, based on the current pressure difference, valve opening degree and corresponding flow rate data.

[0043] The closed-loop control algorithm is PID control, lookup table control, or model predictive control; the control method for gas mixing devices also includes a PID parameter adaptive step: automatically adjusting the proportional, integral, and derivative parameters of the PID controller based on the response performance of the closed-loop system.

[0044] Steady-state determination steps: During the fine-tuning of valve opening, monitor the fluctuation rate of mixing ratio and tank outlet flow rate. When the fluctuation rate is lower than the preset threshold, the system is determined to have entered steady state.

[0045] The control method for gas mixing devices also includes a condition switching step: when the working mode or target ratio is switched, the system oscillation is avoided by limiting the rate of change or gradually adjusting the tank outlet flow.

[0046] The control method for the gas mixing device also includes data recording and optimization steps: recording key operating data including pressure, flow rate, valve opening, valve characteristic model version, and alarm events; optimizing the control model offline based on historical data and sending the optimized strategy to the control system 400.

[0047] The gas mixing device control method also includes safety protection logic, including: closing the corresponding fuel inlet valve, opening the safety valve 120 or bypass valve, recording alarm events, and switching to a safe shutdown or lowest risk operation mode.

[0048] According to some embodiments of the present invention, the gas mixing device control method further includes a safe shutdown procedure: closing all fuel inlet valves in a predefined sequence, performing air purging, opening safety valve 120 to release the pressure inside the tank to a safe range, and disconnecting power after confirming that all valves are in a safe position.

[0049] The control method of this gas mixing device enables real-time acquisition and intelligent adjustment of the flow rate and pressure of each gas. It can dynamically adjust the valve opening according to the pressure fluctuation of the front-end gas source, load changes or target mixing ratio, thereby ensuring mixing accuracy and fuel utilization efficiency.

[0050] The specific implementation process of the gas mixing device control method is as follows: First, after the control system 400 is powered on, the initialization and self-test process is executed. The programmable logic controller 410 sends test signals to each sensor and actuator to confirm that each flow meter and pressure sensor is functioning normally, that each valve actuator can respond normally, and to check whether the initial pressure value of the mixing tank is safe. If any self-test item fails, an alarm is triggered on the human-machine interface 420 and the main valve is prohibited from opening; if the self-test passes, the system receives the operating mode command selected by the operator on the human-machine interface 420, such as selecting "pure fuel mixing mode" to adjust only the ratio of hydrogen, ammonia, and methane, or selecting "air premixing mode" to introduce a specific proportion of air during the fuel mixing process.

[0051] Once the system is operational, it continuously performs data acquisition and display. The programmable logic controller 410 cyclically reads the pressure values ​​of each intake pipeline after depressurization, the instantaneous flow values ​​of each flow meter, the internal pressure of the mixing tank, and the total output flow of the outlet flow meter at a high-speed scanning cycle. These real-time measurements are dynamically displayed on the process flow diagram and data panel of the human-machine interface 420, and are simultaneously recorded in the system's historical database to form an operation log.

[0052] When it is necessary to set or switch operating conditions, the operator sets the target mixing ratio through the human-machine interface 420, such as setting the volume ratio of hydrogen, ammonia, and natural gas to 5:3:2, and sets the target outlet flow rate of the mixing tank and various safety thresholds. The system supports saving multiple sets of such preset operating conditions, which can be recalled with one click.

[0053] Upon receiving the target parameters, the system executes crucial valve control steps. The programmable logic controller (PLC) 410 first calculates based on the target mixing ratio, target total outlet flow rate, and current gas supply pressure in each gas path, using its internally stored valve characteristic model. This model can be an "opening-pressure-flow" characteristic curve fitted based on historical data. The PLC 410 calculates the initial opening of each valve required to approximately achieve the target flow rate using the model and issues commands to drive the hydrogen valve, ammonia valve, natural gas valve, and air valve to their corresponding positions.

[0054] After the valve is activated, the flow closed-loop regulation is initiated. The flow meters in each pipeline feed back the measured actual flow value to the programmable logic controller 410. The programmable logic controller 410 compares the actual flow with the expected flow calculated based on the target mixing ratio. If there is a deviation, the PID control algorithm is activated to generate a fine-tuning signal for the valve opening, continuously reducing the flow error until the actual mixing ratio stabilizes within the allowable range of the target value.

[0055] During closed-loop regulation, the system synchronously executes a steady-state judgment step. The programmable logic controller 410 monitors the real-time mixing ratio calculated from the proportion of each flow and the fluctuation of the mixing tank outlet flow. When the mixing ratio deviation and flow fluctuation rate remain below the preset threshold for a period of time, the system is determined to have reached steady-state operation. If the system fails to reach steady state, a fault diagnosis process may be triggered.

[0056] To ensure long-term control accuracy, the system also periodically performs adaptive learning steps. For example, every eight hours of operation, the programmable logic controller 410 actively analyzes recent valve opening, differential pressure, and flow data, using these new data points to update the original valve characteristic model, enabling the model to self-correct in response to changes in valve performance. After the model is updated or when there is a sudden change in system supply pressure, the programmable logic controller 410 also initiates an adaptive PID parameter routine, automatically optimizing the proportional, integral, and derivative parameters of the PID controller based on recent closed-loop regulation performance indicators such as response speed and overshoot.

[0057] When the operator needs to switch operating modes or target ratios, the system performs a smooth switching procedure. The programmable logic controller 410 does not immediately jump to the setpoint, but instead uses a ramp function limiter to allow the target flow rate to transition to the new value at a limited and gradual rate, and prioritizes stabilizing the total outlet pressure of the mixing tank, thereby effectively preventing pipeline pressure surges and violent fluctuations in the mixing ratio.

[0058] Safety monitoring steps run continuously as a highest-priority background task. The programmable logic controller 410 compares all pressure and flow readings with their safe upper and lower limits in real time. Once an over-limit situation is detected, such as an abnormal drop in gas pressure or the mixing tank pressure exceeding the safety threshold, the programmable logic controller 410 immediately interrupts the normal control logic and executes the safety protection procedure: prioritizing the closure of all fuel inlet valves, opening the safety relief valve or initiating the purging process as needed, recording detailed alarm events on the human-machine interface 420, and issuing audible and visual warnings.

[0059] Finally, the control system 400 continuously performs data recording and optimization steps. All key variables, including but not limited to pressure, flow rate, valve opening, adaptive model version, alarm events, and PID parameters, are fully recorded. This historical data can be used for offline analysis to train a more accurate predictive controller model using more complex algorithms, and can then be sent to the programmable logic controller 410 to update its control strategy, thereby achieving continuous performance improvement for the entire system.

[0060] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0061] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A gas mixing device for the co-combustion of multiple fuels, characterized in that, include: Four intake pipes are used for the input of hydrogen, ammonia, natural gas and air respectively. Each intake pipe is equipped with a first electric valve, a first flow meter and a first pressure sensor at the front end. The mixing tank body has an inlet connected to the outlet of each of the aforementioned air intake pipes. The mixing tank body is equipped with internal components for promoting turbulent gas mixing. The mixing tank body is also equipped with a mixing tank pressure sensor and a safety valve. The gas outlet pipeline is used to deliver the mixed gas to the combustion nozzle, and the gas outlet pipeline is equipped with a second electric valve and a second flow meter; The control system includes a programmable logic controller and a human-machine interface. The programmable logic controller is connected to each of the electric valves, flow meters, and pressure sensors to collect flow and pressure data in real time and control the opening degree of each valve. The control system is configured to perform the following steps: System initialization and self-test, receiving the working mode selected by the operator through the human-machine interface; Real-time data collection and display of flow rate, pressure in each pipeline and pressure in the mixing tank; Based on the set target mixing ratio and outlet flow rate, calculate the initial opening degree of each valve and send control signals; Closed-loop adjustment based on flow feedback is used to bring the actual mixing ratio closer to the target value; An outlet gas flow meter is installed at the outlet of the mixing tank, and the outlet gas valve is adjusted according to the combustion end demand. Execute safety protection logic when pressure or flow exceeds limits.

2. A control method for a gas mixing device, characterized in that, The gas mixing device control method is applied to the gas mixing device according to claim 1, and the gas mixing device control method includes: System initialization steps: Perform a power-on self-test of the programmable logic controller (PLC) and receive the operating mode selected by the operator through the human-machine interface; Data acquisition and display steps: Continuously acquire the pressure and instantaneous flow rate of each intake pipeline, the pressure in the mixing tank and the outlet flow rate, and display and record them in real time; Target setting steps: Receive the target mixing ratio and target outlet flow rate settings; Valve control steps: Based on the target mixing ratio, target outlet flow rate, and current pressure of each gas source, calculate and execute the initial opening of each inlet pipeline valve; subsequently, based on the feedback signal from the flow meter, fine-tune the valve opening through a closed-loop control algorithm to make the actual gas mixing ratio approach the target mixing ratio; Safety monitoring steps: Monitor system pressure and flow in real time. If any parameter is found to be out of limit, execute safety protection logic and prioritize shutting off the fuel intake valve.

3. The gas mixing device control method according to claim 2, characterized in that, The operating modes include pure fuel mixing mode, air premixing mode, manual mode, and maintenance mode; in the air premixing mode, the valve control step simultaneously calculates and controls the valve opening of the air pipeline.

4. The gas mixing device control method according to claim 2, characterized in that, The calculation of the initial opening of each intake pipe valve is specifically as follows: call the pre-stored valve characteristic model or look up the table, and calculate the initial opening by combining the current supply pressure and the target flow rate; The gas mixing device control method further includes: periodically or when calibration conditions are triggered, updating the valve characteristic model based on the current pressure difference, valve opening degree and corresponding flow data.

5. The gas mixing device control method according to claim 2, characterized in that, The closed-loop control algorithm is PID control, lookup table control, or model predictive control; the gas mixing device control method also includes a PID parameter adaptive step: automatically adjusting the proportional, integral, and derivative parameters of the PID controller according to the response performance of the closed-loop system.

6. The gas mixing device control method according to claim 2, characterized in that, The gas mixing device control method also includes a working condition switching step: when the working mode or target ratio is switched, the system oscillation is avoided by limiting the rate of change or gradually adjusting the tank outlet flow.

7. The control method for the gas mixing device according to claim 2, characterized in that, The valve control steps also include a steady-state judgment step: during the fine-tuning of the valve opening, the fluctuation rate of the mixing ratio and the tank outlet flow rate is monitored. When the fluctuation rate is lower than a preset threshold, the system is determined to have entered a steady state.

8. The gas mixing device control method according to claim 2, characterized in that, Also includes: Data recording and optimization steps: Record key operational data including pressure, flow rate, valve opening, valve characteristic model version, and alarm events; Based on historical data, the control model is optimized offline, and the optimized strategy is then sent to the control system.

9. The control method for a gas mixing device according to claim 2, characterized in that, The safety protection logic includes: closing the corresponding fuel intake valve, opening the safety valve or bypass valve, recording alarm events, and switching to a safe shutdown or lowest risk operation mode.

10. The gas mixing device control method according to claim 2, characterized in that, The gas mixing device control method also includes a safe shutdown procedure: closing all fuel inlet valves in a predefined sequence, performing air purging, opening the safety valve to release the pressure inside the tank to a safe range, and disconnecting the power after confirming that all valves are in a safe position.

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