Abstract
The corrosion and material evaluation study in (a) water-based simulated black liquor and (b) water-based simulated black liquor at super-critical conditions was successful. The conclusion from the testing program was that the most resistant alloy for the defined conditions is the chromium-rich carbon steel candidate P91 (UNS K91560). This is a type of creep strength-enhanced ferritic alloy, which is steel designed to retain strength at high temperatures. The P91 abbreviation represents the material's chemical composition, that is, 9 wt% chromium (Cr) and 1 wt% molybdenum (Mo). Further work is required to conclude the corrosion resistance for the P91 quality at supercritical conditions in the welded condition and to better understand caustic corrosion mechanisms.