The paper describes the results of industrial tests associated with the co-combustion of biomass and
agromass with coal and focused on diagnostics and assessment of the effect of fuel type on the accumulation
of solids on the surface of P91 steel tube samples placed in the vicinity of steam superheater in
a commercial large-scale (over 400 MW) circulating fluidized bed boiler.
Analysis of samples indicated the effect of fuel type, as well as the location of the area on the steel tube
on the rate of solids accumulation. Alkali compounds were quite uniformly distributed at both front and
rear sections of the steel tube samples, while calcium and sulfur components were mainly found in the
front area. The average solids accumulation rates calculated for the rear areas of P91 steel tube samples
were roughly two times higher than those for the front ones. The highest solids accumulation rate on the
front area (1.04$109 ms1) was calculated for the case of agromass co-combustion with coal