Time and temperature effects on alkali chloride induced high temperature corrosion of superheaters during biomass firing

Sunday Chukwudi Okoro*, Melanie Montgomery, Flemming Jappe Frandsen, Karen Pantleon

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

161 Downloads (Pure)


The high content of alkali chloride in deposits which form during biomass firing in power plants contributes significantly to corrosion of the superheaters. In order to understand the influence of time and temperature on high temperature corrosion under such harsh conditions, laboratory scale studies as a function of time and temperature were carried out using KCl coated samples of the austenitic stainless steel (TP347H). To understand the progress of corrosion with time, isothermal exposures at 560 oC (from 83.5 h to 672 h), and at 600 oC (from 83.5 h to 168 h) were conducted in a gas mixture comprising of O2, H2O, CO2, HCl and SO2. In addition, samples were subjected to temperature variations between 560 oC and 600 oC to gain insights on the influence of temperature. The microstructure and elemental composition of the corrosion products resulting from the exposures were studied with scanning electron microscopy and energy dispersive X-ray spectroscopy, respectively. The results show that corrosion attack progressed with time such that the thickness of the consistently identified three regions of corrosion products increased with time, therefore suggesting that the corrosion products were not protective. Also, exposures under varying temperature conditions revealed that an increased corrosion attack would always occur once the superheater experiences a higher temperature, because, a memory effect from prior exposure at higher temperature propagates more corrosion attack during subsequent exposure to a lower temperature.
Original languageEnglish
JournalEnergy and Fuels
Issue number7
Pages (from-to)7991-7999
Publication statusPublished - 2018


  • Biomass firing
  • Alkali chloride
  • High temperature corrosion
  • Thermal variation

Fingerprint Dive into the research topics of 'Time and temperature effects on alkali chloride induced high temperature corrosion of superheaters during biomass firing'. Together they form a unique fingerprint.

Cite this