Bagasse burns best when it gets air in the right place, and secondary air makes a big difference. SA fans supply that secondary air into the furnace to help the fuel burn fully.
When secondary air is short or poorly delivered, bagasse burns incompletely, wasting fuel and making more unburnt carbon. Good SA fans help the boiler burn clean and steady.
This guide explains what SA fans do, why secondary air improves combustion, and how to keep them running reliably.
What SA Fans Do
SA fans, or secondary air fans, push air into the furnace above the fuel bed. This secondary air mixes with the burning bagasse and the gases coming off it.
That mixing is what completes the burn, because it brings oxygen to fuel and gases that would otherwise pass through unburnt. The fans place the air where the combustion needs it.
By supplying steady secondary air, the fans help the boiler burn its bagasse fully and raise steam evenly.
Why Secondary Air Improves Combustion
Bagasse gives off gases as it heats, and those gases need oxygen and mixing to burn. Without enough secondary air, they escape unburnt, wasting fuel and fouling the boiler.
Well placed secondary air mixes with the gases and completes the burn, so more heat is released from the same bagasse. That means better steam raising and cleaner flue gas.
Good combustion also leaves less unburnt carbon, so the boiler runs cleaner and gets more from every tonne of fuel.
Signs SA Fans Need Attention
SA fans in trouble show up in the burn and the flue gas.
- Incomplete burning of bagasse
- More unburnt carbon leaving the furnace
- Uneven or weak secondary air flow
- Vibration or noise from the fan
- Steam raising that falls with the same fuel
What Makes a Good SA Fan?
An SA fan is judged by steady air delivery and reliable running.
Steady Air Delivery
The fan must deliver secondary air steadily and where the furnace needs it. Steady delivery is what completes the burn and keeps combustion clean.
Strong, Balanced Build
Fans run continuously through the season, so they need a strong, balanced build to run without vibration. A sound fan holds up under long duty.
Keeping SA Fans Running
Routine attention keeps SA fans supporting a clean burn.
- Watch the burn for signs of incomplete combustion
- Keep the secondary air flow steady and correct
- Check the fan for vibration, noise, or wear
- Maintain bearings and the drive for reliable running
Common Questions About SA Fans
SA fans supply secondary air into the furnace above the fuel bed, which mixes with the burning bagasse and gases to complete the burn and improve combustion.
Bagasse gives off gases that need oxygen and mixing to burn. Secondary air completes that burn, so more heat is released and less fuel is wasted.
Gases escape unburnt, wasting fuel, fouling the boiler, and leaving more unburnt carbon. Good SA fans prevent that by supplying steady secondary air.
Keeping the air flow steady, watching for vibration and wear, and maintaining bearings and the drive keep the fans running cleanly through the season.
Complete the Burn, Raise More Steam
SA fans help the boiler burn its bagasse fully by placing secondary air where combustion needs it. A complete burn means more steam, cleaner flue gas, and better use of fuel.
If your bagasse is burning incompletely, secondary air is worth reviewing. Explore our boiler and co-generation equipment to help your boiler burn clean.
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