Fireside corrosion testing is a complex process with many variables. Testing at laboratory, pilot or full
scale presents many difficulties. Pilot scale testing has been found to offer advantages over laboratory
or full scale plant based testing, although limitations still remain. Pilot scale testing enables a wide
range of test parameters to be examined with relatively good control of test parameters relative to full
scale plant, whilst ensuring all combustion related parameters are examined, something that is often
missing from simulated, laboratory scale work. E.ON’s 1MWth Combustion Test Facility has been used
to conduct fireside corrosion test work whilst firing a variety of coal and coal-biomass blends in air-fuel
fired mode and coals with various sulphur and chlorine contents in oxy-fuel fired mode. Metallographic
examination has been used to accurately determine metal losses while scanning electron microscopy
and x-ray elemental analysis has been used to characterise the corrosion damage. The rates and
types of corrosion produced are described for both the furnace wall and superheater / reheater areas of
pulverised fuel fired boilers. Both co-firing and oxy-fuel firing have the potential to increase, sometimes
dramatically, fireside corrosion rates.
Key words: Furnace Wall, Superheater, Fireside Corrosion, Biomass Co-firing, Oxy-fuel, Pilot Scale