Sulfuric acid is one of the most important elementary substances of the chemical industry. There is no stainless steel or even a nickel base alloy available which is suitable over the entire concentration range. This paper will give corrosion data in up to 75 % sulfuric acid at boiling temperature for various commercial grades as well as for some new developmental alloys.
In context of acceptability of 17-4 PH in sour service, an literature survey of complex metallurgy of this grade was done following a mechanical rupture in service. In addition, three 17-4 PH materials were studied in terms of microstructure, mechanical properties and susceptibility to sulfide stress cracking.
The approach to the commissioning of a heat-recovery steam generator in the industry has varied from project to project. One school of thought contends that no chemical cleaning (or minimal) is required. The second school of thought contends that a complete chemical cleaning is required. This report discusses these differences, and a properly designed and well executed cleaning with desired results.