- Location
- Burton on trent
Sorry, for this being a long one,
But I could do with some advice from someone with good experience of biomass boilers.
I have a Froling TM250 boiler (250kw), but alot of these biomass boiler operate in a similar manner.
It's running well, but I'm only managing about 180/190kw on the current fuel and would like to try and push the boiler harder, even if it reduces the fuel efficiency a bit.
On other fuels I have had it at/or close to 250kw
The fuel:
It's Class A waste wood (which the boiler is certified to burn), very dry and smashed up with lots of fines/dust and small pieces.
The boiler has many settings you can change:
Fuel infeed
Primary air flap
Secondary air flap
Flue gas re-circulation (FGR) fan speed
Primary air reduction from FGR
Grate speed
etc etc
The FGR basically pulls flue gases from the chimney and put them back into the primary air, the FGR fan speed can be altered as can the proportion of fresh primary air against flue air.
The boiler has a combustion chamber temperature (CCT) sensor and flue gas temperature (FGT) sensor.
If the CCT reaches 1000c or the FGT reaches 190c the boiler will back off the infeed to protect itself, thus reducing output.
So it seems to be a matter of balancing these temperatures to get max output.
The boiler has graphing software continuously collecting data on everything and showing graphs in realtime on a PC
Findings/views (could be wrong) (please comment):
Increasing secondary air reduces the CCT, so for dry fuel run lots as this increases output
Increasing FGR reduces the CCT, but increases the FGT, which helps improve fuel consumption/efficiency
Increasing primary air increases the CCT and FGT so reduce with dry fuel
Reducing primary air and replacing with FGR air seems to increase output with this fuel to a point.
Running the grate slow seems necessary to ensure the fuel has time to burn out before going to the ash auger
There is a lot of complex settings I can change and most/all work on a gradual basis, in that, as temperatures change in the boiler the flaps/fans alter on a gradual basis.
Also a setting change can take many hours to show an outcome, which makes life hard.
Chris
But I could do with some advice from someone with good experience of biomass boilers.
I have a Froling TM250 boiler (250kw), but alot of these biomass boiler operate in a similar manner.
It's running well, but I'm only managing about 180/190kw on the current fuel and would like to try and push the boiler harder, even if it reduces the fuel efficiency a bit.
On other fuels I have had it at/or close to 250kw
The fuel:
It's Class A waste wood (which the boiler is certified to burn), very dry and smashed up with lots of fines/dust and small pieces.
The boiler has many settings you can change:
Fuel infeed
Primary air flap
Secondary air flap
Flue gas re-circulation (FGR) fan speed
Primary air reduction from FGR
Grate speed
etc etc
The FGR basically pulls flue gases from the chimney and put them back into the primary air, the FGR fan speed can be altered as can the proportion of fresh primary air against flue air.
The boiler has a combustion chamber temperature (CCT) sensor and flue gas temperature (FGT) sensor.
If the CCT reaches 1000c or the FGT reaches 190c the boiler will back off the infeed to protect itself, thus reducing output.
So it seems to be a matter of balancing these temperatures to get max output.
The boiler has graphing software continuously collecting data on everything and showing graphs in realtime on a PC
Findings/views (could be wrong) (please comment):
Increasing secondary air reduces the CCT, so for dry fuel run lots as this increases output
Increasing FGR reduces the CCT, but increases the FGT, which helps improve fuel consumption/efficiency
Increasing primary air increases the CCT and FGT so reduce with dry fuel
Reducing primary air and replacing with FGR air seems to increase output with this fuel to a point.
Running the grate slow seems necessary to ensure the fuel has time to burn out before going to the ash auger
There is a lot of complex settings I can change and most/all work on a gradual basis, in that, as temperatures change in the boiler the flaps/fans alter on a gradual basis.
Also a setting change can take many hours to show an outcome, which makes life hard.
Chris