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Tag: Materials of Construction

Introducing ammonia flow-induced corrosion

In recent years, extensive and severe internal attack has been observed of carbon steel equipment and lines in aqua ammonia service at several Yara manufacturing sites across the globe. In all cases, the damage has a distinct flow-accelerated corrosion (FAC) signature which challenges the current understanding of FAC. All features typically observed for this kind of damage mechanism, that seem to be specific to the NH3 recovery section of ammonia plant, are reported. Upgrading the material of construction for this unit, will solve this failure mode, but a leak would potentially generate health and safety problem for the release of ammonia.

Boosting sulphuric acid production with oxygen

A plant operating a spent acid decomposition furnace as part of its sulphuric acid production facility desired to increase acid production primarily by processing additional spent acid while making minimal modifications to the plant equipment and operations. The Messer solution entailed introducing oxygen in two steps, both as an enrichment to the combustion air and by direct injection into the furnace. The resulting performance improvements exceeded the project objectives for acid production and spent acid decomposition, without increasing NOx emissions. This paper provides a summary of the system start-up and tuning and presents the resulting improvements and lessons learned.