Utilisation of CFBC and IGCC Residues
AUTHOR: Deborah M B Adams
DATE: November 2004
CFBC is a clean coal technology that generally uses limestone as the sorbent for sulphur capture and produces large volumes of residue. Unreacted sorbent left in the ash contributes to its reactivity and influences its suitability for various applications. CFBC is an appropriate technology for co-combustion which also influences the ash composition. CFBC ash can be used for concrete, and as structural fill. The reactivity of the ash means that it can swell in some applications, which can be a drawback.
In some applications the reactivity of CFBC ash can be used, such as in the remediation of acid mine drainage, in amending soils and in pollution control. There has been less research on IGCC residues and less development of markets, as there are only six plants globally. However, there is potential for IGCC residues to be used as aggregate, in road bases and specialised cements. Blending, processing and storage of CFBC residues is important to manage its reactivity and to produce a uniform, stable, product that is available all year round. The standards that exist can exclude CFBC and IGCC residues by their focus on conventional coal ash. However, some standards are being modified to include other residues. As clean coal technologies such as CFBC and IGCC become more widespread, more ash will be produced in these forms, and then more work will be directed into finding and developing appropriate uses for the residues.