Burn-off (solid fuel combustion)
The burn-off is the fluidic combustion principle of combustion with coarse solids, such as firewood in boilers .
Burn through
When it burns through, the air is guided through the fuel via a grate . All of the fuel is heated and burns at the same time. This type is used in classic wood-burning stoves .
Upper burn
When burning at the top, the air is directed from the side to the burning material. In this way, the gas release is slowed down. This technology is used for tiled or basic furnace systems, etc.
Lower burn
Here the hot exhaust gases do not flow upwards as they normally do, but are forced downwards or to the side by a mechanical ventilation system , where they then burn out in a secondary chamber. In this way, only the bottom layer of the fuel is burned.
The lower burn-up divides the combustion into a drying and gasification zone and a burn-out zone.
Explained in more detail at wood gasification boiler.