Release of alkali metals during biomass thermal conversion

Biomass is material derived from living or recently living organisms and is a potential source of energy with very specific properties. Biomass has great potential to replace fossil fuels in energy systems, offering environmental benefits due to its carbon neutrality and renewability. However, the firing and co-firing of biomass can lead to problems such as slagging, fouling and metal corrosion, due to its high chlorine, potassium and sodium content. During thermochemical conversion, the alkali species can be released from biomass through vaporization; the gaseous species can react further or undergo physical transformations to either condense on fly ash or form aerosols, which can further deposit on heat transfer surfaces and lead to complex metal reactions [1] resulting in corrosion on these surfaces due to the interaction between the alkali species and metals.