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Mpho Marekwa

Metal Dusting Corrosion

Supervised by Dr K Marcus and sponsored by PetroSA, Mpho is investigating metal dusting corrosion. Metal dusting is a disintegration of metals and alloys into a dust of graphite and fine metal particles and is caused by strongly carburizing atmosphere, such as Syngas CO-H2, and Hydrocarbons. It occurs mainly in an intermediate temperature range of 400-8000C. It causes pitting to the affected materials. Metal dusting is a recurring problem within the petrochemical industries that has serious consequences for plant efficiency and reliability, as well as for operational safety. When it does occur, rapid, catastrophic failure of the plant components can result with attendant high repair costs and the inevitable loss of production. The underlying factors governing its occurrence are not fully understood and therefore studies under closely monitored conditions in atmospheres that simulate those encountered in service are essential. Metal dusting affects many other systems, including synthetic natural gas plants, Coal gasification, Fired heaters handling hydrocarbons, Steam reformers, Industrial furnaces, and CO2 cooled nuclear reactors. Mpho will be using Optical and Scanning electron microscopy to examine the metallography of the corroded samples, the extent of damage, pit size, evolution of the microstructure, and composition of the products of corrosion. The result will hopefully provide more understanding as far as metal dusting mechanism is concern.