The Agglomeration in the Fluidized Bed Boiler During the Co-Combustion of Biomass with Peat

Conclusions

The formation of bed material coatings during the co-combustion of peat and biomass is caused by iron, calcium, aluminum and silicon. No signs of sodium or calcium sulfates were observed in bed material samples. Sulfates were observed in fly ash samples, when the amount of wood was 55% of the fuel mixture. Thus the bed material agglomeration during peat and biomass co-combustion is due to the partial melting of aluminosilicates, rather than the formation of low melting salts. Iron is found from the bed material coatings and may act as a flux in the melting processes of the silicates. When the agglomeration progresses, the coated sand particles are molten on the surface as seen from the increased amounts of potassium, sodium and calcium. The role of iron is not so significant in the adhesive material.