Caustic cracking from potassium hydroxide in Syngas

Potassium hydroxide (KOH) stress corrosion cracking (SCC) caused failure of a type 304L (UNS S30403) stainless steel bypass in a steam methane reforming unit. KOH was from a potassium-promoted catalyst. A test program determined that hydrogen and/or carbon monoxide (CO) were necessary to promote this cracking at relatively low temperatures. Sodium hydroxide (NaOH) was found to cause SCC at lower temperatures than KOH.