Utilization of Biomass Ashes

Useful application of ashes produced in the thermal conversion of biomass can contribute to the green image of biomass as a source of sustainable energy. This chapter gives an overview of the different forms of ash utilization that exist or are being developed for biomass ashes. The first section reviews options for ashes from co-firing of biomass and coal, both established forms of utilization in cement and concrete, and alternative options,

e.g.

, manufacture of lightweight aggregates. The second section discusses utilization options for residues from “pure” biomass combustion. The large variation in biomass fuels and installation types makes this a complex issue. Besides recycling of clean wood ash to forests, these are all emerging forms of utilization. The third section discusses the specific issues related to the utilization of carbon-rich ashes from biomass gasification and pyrolysis.