Heat recovery systems are used in the manufacture of sulfuric acid. Depending on the process available, sulfuric acid at concentrations of 93 to 99.5 weight percent can be used. The trend towards higher levels of efficiency in the recovery of heat in sulfuric acid manufacturing is leading to higher temperatures in the absorption systems and hence to more severe demands on the corrosion resistance of metallic materials. Although there are several engineering and material concepts available, from a corrosion science and engineering point of view, it is still a challenge to better understand the corrosion mechanism and the role of the alloying elements in stainless steels and NiCrMo alloys. This paper contains an extended literature review covering numerous aspects of the complex corrosion system that we are faced with in such applications. Further on, the paper also addresses corrosion testing results, which may help to understand some observations people experienced in the past in this complicated matter. Finally, the paper also contains a short section covering the state of the art review of the most common materials for this technology.
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