High temperature corrosion of superheater steels by KCl and K2CO3 under dry and wet conditions

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: Lehmusto J, Yrjas P, Skrifvars BJ, Hupa M
Publisher: ELSEVIER SCIENCE BV
Publication year: 2012
Journal: Fuel Processing Technology
Journal acronym: FUEL PROCESS TECHNOL
Volume number: 104
Start page: 253
End page: 264
Number of pages: 12
ISSN: 0378-3820


Abstract

The influence of both solid KCl and solid K2CO3 on the oxidn. behavior of a ferritic 10CrMo type steel and a nickel-​based Alloy 625 type steel was investigated in the lab. Samples were exposed for a week at temps. of 500 °C, 550 °C, and 600 °C. The role of water vapor was also studied by carrying out exposures under two different atmospheres: dry air, and air with a water content of 30​%. Analyses were performed with SEM​/EDXA to det. the extent of corrosion, the elemental distribution, and the identification of corrosion products.

Both salts were found to be corrosive towards both steels, but the influence of KCl was significantly greater than that of K2CO3. In terms of durability, Alloy 625 exhibited higher corrosion resistance than 10CrMo. In the case of 10CrMo, the oxide formed always consisted of iron oxide with a chromium-​rich region near the original steel surface. In the case of Alloy 625, the oxide consisted mainly of nickel oxide when it formed in the presence of KCl, and chromium oxide when it formed in the presence of K2CO3.


Keywords

Ferritic steel, High temperature oxidation, Nickel-based alloy, Potassium carbonate, Potassium chloride, Water vapor

Last updated on 2019-19-06 at 04:20