When addressing multi-fuel compatibility requirements, the design of the switching mechanism in a multi-fuel burner must revolve around core elements such as fuel characteristic differences, mixing uniformity, combustion stability, and safety protection. Seamless switching and stable operation between different fuels can be achieved through the synergy of a modular feeding system, intelligent adjustment components, and a closed-loop control strategy.
The feeding system of a multi-fuel burner requires a modular, independent design, with dedicated delivery modules for gaseous, liquid, and solid fuels. Gaseous fuel flow rate is controlled by a pressure regulating valve to ensure concentration stability when mixed with air. Liquid fuel requires precision atomizing nozzles to break the fuel into micron-sized particles using high-pressure injection, increasing the contact area with air. Solid fuel requires an automatic crushing device and a screw feeder to convert the fuel into a uniform powder, avoiding combustion fluctuations caused by uneven particle size. Each module is independently opened and closed via solenoid or pneumatic valves to prevent cross-contamination, and is connected to the main feeding pipeline via quick-connect couplings for easy maintenance and replacement.
The core challenge of fuel switching lies in the differences in calorific value, volatility, and combustion rate among different fuels. For example, natural gas burns quickly, requiring rapid air supply to prevent backfire; while diesel fuel has a high calorific value, necessitating a longer mixing time to ensure complete combustion. The switching mechanism needs to integrate dynamic adjustment components, such as variable geometry nozzles and a rotating air distribution plate. The nozzles are driven by a servo motor, adjusting their outlet cross-sectional area according to fuel type to control fuel injection speed and diffusion angle. The air distribution plate uses a double-layer swirling structure: the outer layer forms a spiral airflow enveloping the fuel, while the inner layer uses an intelligent supplemental air device to regulate oxygen supply, ensuring combustion intensity in the core flame area. When switching fuel types, the system automatically adjusts the relative positions of the nozzles and air distribution plate to optimize the mixing ratio.
Combustion stability depends on real-time monitoring and closed-loop control of key parameters. The switching mechanism needs to integrate a multi-parameter sensor network, including temperature probes, pressure sensors, and flame monitoring probes. Temperature probes are positioned in key areas of the combustion chamber to provide real-time feedback on the thermal field distribution; pressure sensors monitor the fuel and air supply pressures to prevent mixture imbalances due to pressure fluctuations; and flame monitoring probes use spectral analysis to detect combustion status and identify abnormal conditions such as backfire and flameout. All data is transmitted to the central controller, where a preset algorithm model calculates the optimal parameter combination to drive the actuators to adjust fuel flow, air-fuel ratio, and ignition energy, achieving dynamic balance in the combustion process.
Safety protection is paramount in multi-fuel switching design. The system must be equipped with multiple redundant protection mechanisms, including an emergency check valve, a nitrogen oxide capture device, and an automatic pressure relief channel. The emergency check valve is installed in the fuel supply line; upon detecting abnormal operating conditions, it closes all supply lines within two seconds using a spring-loaded self-compensating structure to prevent fuel leakage. The nitrogen oxide capture device uses a removable catalytic filter, automatically switching catalyst types for high-emission fuels (such as coal gas) to ensure emissions meet standards. The automatic pressure relief channel is controlled by a pressure threshold; when the combustion chamber pressure exceeds a safe value, it automatically opens the pressure relief port to prevent equipment damage.
The control system is the brain of the switching mechanism, integrating fuel identification, parameter matching, and fault diagnosis functions. The system has forty built-in fuel blending schemes, covering common types such as natural gas, diesel, and biomass fuels. When a fuel type is selected at the operator's end, the controller automatically matches the gas supply pressure, combustion air volume, and temperature rise curve through a fuel characteristic database, simultaneously adjusting six key parameters. A parameter window is retained on the interface for technicians to manually fine-tune the parameters, meeting the refined control needs of complex fuel blending. Furthermore, the system continuously optimizes the control strategy through machine learning algorithms, automatically correcting parameter combinations based on historical operating data to improve switching efficiency and combustion stability.
Thermal output stability is a crucial evaluation indicator for multi-fuel burners. The switching mechanism must achieve uniform heat distribution and efficient utilization through heat-conducting fins and a waste heat recovery device. The thermal output port features pre-set variable-pitch heat sinks, adjusting the fin spacing according to the calorific value of different fuels and rearranging the hot gas path to ensure a constant output temperature. The waste heat recovery device uses intelligent hinges to determine waste heat temperature; when using low-calorific-value fuels (such as biogas), it automatically activates the recovery system to capture 70% of the reusable thermal energy, improving overall energy utilization efficiency.
Future multi-fuel burner switching mechanisms will evolve towards intelligence and adaptability. By introducing IoT technology, data interaction between the equipment and the cloud is achieved, enabling remote monitoring of operational status and the delivery of maintenance suggestions. Combined with artificial intelligence algorithms, an adaptive fuel identification module has been developed, utilizing sensors to analyze fuel composition in real time and automatically generate the optimal combustion scheme. Furthermore, the application of new materials (such as ceramic alloy composite protective plates) will improve the equipment's heat resistance and sealing performance, achieving zero fuel leakage under 3,000 hours of continuous operation, further expanding the application scenarios of multi-fuel burners.
