Convegni ATI - Accesso riservato soci CTI

Autore: G. Belz, P. Caramuscio, F. De Luca, G. Valenti

Collana: BT - 34 - Mag 06 - Energy: production, distribution and conservation

Note:
There is an increasing interest towards the use of fluidized bed combustion (FBC) technology. Among the main advantages of FBC technology there is the possibility of burning low-rank coals with high sulfur and ash content as well as alternative energy sources such as biomasses. An additional technological advantage is the removing in situ of sulfur dioxide generated during he combustion processes by means of limestone-based sorbents added to the bed material.
Despite these positive aspects, both utilization and disposal of fluidized bed combustion (FGC) ashes are instead complicated with respect to conventional PC ashes by their chemical and mineralogical composition. FBC ashes present a quite high content of CaO and CaSO4 responsible for exothermal and expansive phenomena upon hydration; furthermore, due to the low combustion temperature, they contain a limited amount of glass phase and therefore a poor pozzolanic activity.
These characteristics prevent their possible utilisation as a pozzolanic or filler addition in Portland based cements or concrete products.
In this paper, the suitability of FBC ash as raw feed component for the manufacture of calcium sulfoaluminate (CSA)cements is assessed, which can be utilized for a wide range of applications.