Abstract In Sulfur Recovery Units (SRU), the piping transporting various gas streams to the incinerator can experience severe corrosion and plugging due to condensation of sulfur, water and/or sulfuric acid. Case histories of these problems have occurred even in lines with properly-designed steam tracing systems. This paper will discuss the impacts of different feed gas combinations on the risk of plugging and corrosion in steam traced areas and refractory-lined sections; recommendations for design details of the piping systems; vertical vs. horizontal incinerator inlets and the locations of possible corrosion. A key lesson learned was that to avoid corrosion, unit operators need a good understanding of which gas streams can and cannot be combined. Avoiding corrosion is even more critical in today’s ultra-large units which can have gas lines as large as NPS 84 diameter, as the economic impacts of down time and maintenance costs are significantly amplified.