Corrosion Investigations in Straw-Fired Power Plants in Denmark

Melanie Montgomery, Flemming Frandsen, A Karlsson, OH Larsen

Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review


In Denmark, straw and other types of biomass are used for generating energy in power plants. Straw has the advantage that it is a "carbon dioxide neutral fuel" and therefore environmentally acceptable. Straw combustion is associated with corrosion problems which are not encountered in coal-fired plants. During combustion, potassium chloride and SO2 are released in the flue gas and through condensation and deposition processes, they will result in the formation of superheater ash deposits rich in potassium chloride and potassium sulphate. Such ash deposits give rise to varying degrees of accelerated corrosion. The type of corrosion attack can be directly ascribed to the composition of the deposit and the metal surface temperature. A series of field tests have been undertaken in the various straw-fired power plants in Denmark, namely the Masnedø, Rudkøbing and Ensted CHP plants. Three types of exposure were undertaken to investigate corrosion: a) the exposure of metal rings on water/air cooled probes, b) the exposure of test tubes in a test superheater, and c) the exposure of test tubes in existing superheaters. Thus both austenitic steels and ferritic steels were exposed in the steam temperature range of 450-600°C. The corrosion rates were assessed by precision measurements of material loss and internal corrosion. The corrosion products and course of corrosion for the various steel types were investigated using light optical and scanning electron microscopy. Corrosion mechanisms are discussed in relation to temperature and deposit composition. The practical implications of corrosion in straw-fired power plants will also be discussed.
Original languageEnglish
Title of host publicationEffects of coal quality on power plant management : ash problems, management and solutions
EditorsAK Mehta and SA Benson
Place of PublicationPalo Alto
Publication date2001
Publication statusPublished - 2001
EventEffects on Coal Quality on power Plant management - Park City, Utah, USA
Duration: 1 Jan 2001 → …


ConferenceEffects on Coal Quality on power Plant management
CityPark City, Utah, USA
Period01/01/2001 → …


  • Corrosion


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