High temperature corrosion during biomass firing: improved understanding by depth resolved characterisation of corrosion products. (January 2015)

• Record Type: Journal Article
• Authors: Okoro, S. C.; Montgomery, M.; Frandsen, F. J.; Pantleon, K.
• Is Part Of: Materials at high temperatures. Volume 32:Number 1/2(2015)
• Page Start: 92
• Page End: 101
• Publication Date: 2015-01
• Subjects: Fireside corrosion, -- Active oxidation, -- Sulphidation, -- KCl deposit; Materials at high temperatures -- Periodicals; High temperatures -- Periodicals; 620.1121705
• DOI: 10.1179/0960340914Z.00000000081
• Languages: English
• ISSNs: 0960-3409

Abstract

Abstract : The high temperature corrosion of an austenitic stainless steel (TP 347H FG), widely utilised as a superheater tube material in Danish power stations, was investigated to verify the corrosion mechanisms related to biomass firing. KCl coated samples were exposed isothermally to 560°C, for one week, under conditions simulating straw-firing. Thorough characterisation of the exposed samples was conducted by the analysis of sample cross-sections applying microscopy and spectroscopy based techniques. Cross-section analysis revealed the microstructure, as well as chemical and morphological changes within the near surface region (covering both the deposit and the steel surface). Such cross-section analysis was further complemented by plan view investigations (additionally involving X-ray diffraction) combined with removal of the corrosion products. Improved insights into the nature of the corrosion products as a function of distance from the deposit surface were revealed through this comprehensive characterisation. Corrosion attack during simulated straw-firing conditions was observed to occur through both active oxidation and sulphidation mechanisms.