MATERIALS EXPERIENCE IN A METHANE REFORMING PLANT

摘要

Metal dusting failure of an UNS N06600 (alloy 600) component in the neck section of a secondary methane reformer, and the subsequent catastrophic failure of the reformer shell, in a plant that converts natural gas to synthetic fuels was previously described. Plant experience with this high temperature degradation mechanism appears to contradict most published data on the topic in that the chromium-nickel-iron alloy UNS NO8810 (Alloy 800H) has been found to vastly out-perform the high nickel UNS N06600 (Alloy 600) in this specific process environment. An alloy exposure program was initiated in order to try to gain a greater understanding of the practical limitations of metallic materials to this environment. Both high chromium-nickel-iron and nickel-base alloys were exposed. Results from this 6 month exposure suggests that increasing resistance could be achieved with increasing chromium content. Alloying additions of aluminum appears to be ineffective when the alloy oxide layer is deliberately destroyed Results with an eutectic 50%Cr-50%Ni thermal sprayed coating were encouraging and may provide metal dusting resistance provided that the application deficiencies can be overcome.