Fuel switching for dual-fuel burners generally falls into two modes: online automatic switching (without stopping the burner) and offline manual switching (requiring a shutdown). Modern industrial and commercial burners are typically equipped with control cabinets that allow for safe, smooth fuel transitions via the following standardized steps:
1. Confirming the Switching Mode: Fully automatic/online switching—advanced burners (such as certain imported multi-fuel or dual-fuel models) support automatic switching controlled by a PLC system based on fuel supply conditions while the burner is running. Manual/shutdown switching—this is the most common traditional safety mode; it requires shutting off the current fuel supply and completing a pipeline purge before igniting the alternative fuel.
2. Standard Switching Steps (Offline/Manual Mode): Stop combustion—switch the burner control panel to "Stop" (Off), wait for the main flame to extinguish, and allow the equipment to complete its purge cycle. Shut off the current fuel—if switching from gas to oil: first close the manual valve and solenoid valve on the main gas line to ensure no gas leakage; if switching from oil to gas: close the oil supply and return valves and stop the oil pump. Pipeline purging and draining—for oil lines, a purging fluid is usually required to clear residual heavy or light oil from the pipes, preventing carbon buildup or blockages. Switch valve trains and adjust air dampers—open the new fuel line by turning the manual valve. Adjust air damper ratios—since the air requirements (air-fuel ratio) differ between gas and oil, the servo motor or damper flap angle usually needs readjustment to ensure complete combustion of the new fuel. Set the combustion program—turn the fuel selector switch on the control box to the new fuel setting (e.g., from "Gas" to "Oil"). Re-ignition—restart the burner; the controller will automatically execute sequences such as pre-purge, ignition, and flame detection. Observe the flame color and combustion status, and use a flue gas analyzer to fine-tune the air-fuel ratio if necessary.
3. Precautions: Strictly avoid "hot switching" (switching while the flame is active)—never open the valve for the alternative fuel without first completely shutting off the current fuel supply, as this could cause a deflagration or explosion. Pressure and Temperature Matching: Ensure the gas supply meets the rated operating pressure; heavy oil must be sufficiently heated to achieve the appropriate viscosity before switching, whereas light oil requires no heating. Safety Interlock Protection: After switching, verify that the gas Valve Proving System (VPS) or fuel pressure switch is functioning correctly.
Fuel switching for dual-fuel burners generally falls into two modes: online automatic switching (without stopping the burner) and offline manual switching (requiring a shutdown). Modern industrial and commercial burners are typically equipped with control cabinets that allow for safe, smooth fuel transitions via the following standardized steps:
1. Confirming the Switching Mode: Fully automatic/online switching—advanced burners (such as certain imported multi-fuel or dual-fuel models) support automatic switching controlled by a PLC system based on fuel supply conditions while the burner is running. Manual/shutdown switching—this is the most common traditional safety mode; it requires shutting off the current fuel supply and completing a pipeline purge before igniting the alternative fuel.
2. Standard Switching Steps (Offline/Manual Mode): Stop combustion—switch the burner control panel to "Stop" (Off), wait for the main flame to extinguish, and allow the equipment to complete its purge cycle. Shut off the current fuel—if switching from gas to oil: first close the manual valve and solenoid valve on the main gas line to ensure no gas leakage; if switching from oil to gas: close the oil supply and return valves and stop the oil pump. Pipeline purging and draining—for oil lines, a purging fluid is usually required to clear residual heavy or light oil from the pipes, preventing carbon buildup or blockages. Switch valve trains and adjust air dampers—open the new fuel line by turning the manual valve. Adjust air damper ratios—since the air requirements (air-fuel ratio) differ between gas and oil, the servo motor or damper flap angle usually needs readjustment to ensure complete combustion of the new fuel. Set the combustion program—turn the fuel selector switch on the control box to the new fuel setting (e.g., from "Gas" to "Oil"). Re-ignition—restart the burner; the controller will automatically execute sequences such as pre-purge, ignition, and flame detection. Observe the flame color and combustion status, and use a flue gas analyzer to fine-tune the air-fuel ratio if necessary.
3. Precautions: Strictly avoid "hot switching" (switching while the flame is active)—never open the valve for the alternative fuel without first completely shutting off the current fuel supply, as this could cause a deflagration or explosion. Pressure and Temperature Matching: Ensure the gas supply meets the rated operating pressure; heavy oil must be sufficiently heated to achieve the appropriate viscosity before switching, whereas light oil requires no heating. Safety Interlock Protection: After switching, verify that the gas Valve Proving System (VPS) or fuel pressure switch is functioning correctly.