Bubbling fluidized bed (BFB) combustion can be applied to a wide range of fuels, from dry-wood fuel and peat to high-moisture forest residues, sludge and even solid recovered fuels. Our BFB combustion system is based on Metso’s proven BFB technology utilized in over 170 operating plants around the world. We offer BFB combustion in the range of approx. 10-60 MW.
In the BFB combustion system, fuel is fed above the hot fluidizing sand bed. The fuel drying and combustion of volatiles begins already in the freeboard, while the heavier fuel particles burn inside the sand bed. The carefully designed overfire air jets complete the combustion with very low emissions in all load conditions. The ash passes from the furnace with the flue gas, while the unburned coarse impurities coming with the fuel are removed from the boiler via the large openings in the furnace floor.
Biomasses easily available in the vicinity of the boiler plant are extremely suitable for fluidized bed combustion. In addition to this, solid recovery fuel or sludge can be used as a mixing fuel. The advantage of this combustion method is the possibility to use fuels which are moist and have low thermal value.
The boilers are easy to operate and maintain, have high availability and meet the emission requirements. The flue gas emissions are lower than all emission standards in force. The boiler plant can be equipped with auxiliary items such as a flue gas scrubber or precipitator.
In the design of boilers and combustion devices, we have taken notice of recent research results and also of the long-term operating experience of users. The boiler plants are designed to be automatic. Depending on each individual case, they can be operated either under periodic control or with just one person per shift.