However, in numerous publications [e.g. Refs. [4e6]] it is reported
that combustion processes (particularly co-combustion of
coal and biomass) are often associated with accumulation of solids
and formation of troublesome ash deposits on heat transfer surfaces,
particularly those located in the boiler convective section.
The deposits are in many cases considered to be brought about by
biomass ash alkali [7e13] and are often responsible for boiler
emergency shutdown, decrease of the heat transfer rate, or damage
of heat transfer elements and shortening of their lifetimes.