TOWARDS BETTER UNDERSTANDING OF TEMPERATURE GRADIENTS IN SUPERHEATER CORROSION

B3 Non-refereed conference proceedings


Internal Authors/Editors


Publication Details

List of Authors: Markus Engblom, Daniel Lindberg, Patrik Yrjas, Jonne Niemi, Tor Laurén, Mikko Hupa
Editors: Jinghai Li, Fei Wei, Xiaojun Bao, Wei Wang
Place: Beijing
Publication year: 2014
Publisher: Institute of Process Engineering, Chinese Academy of Sciences
Book title: 11th International Conference on Fluidized Bed Technology, CFB-11


Abstract

This paper presents a novel laboratory method for superheater corrosion experiments in which a temperature gradient is applied over the deposit and steel. Experiments using salt mixtures of NaCl/Na2SO4 or KCl/K2SO4 show alkali chloride transport (NaCl, KCl) within the salt layer, and to the steel surface. The alkali chloride is vaporized from the salt grains, transported down the temperature gradient, and deposited on surfaces with lower temperature. Mathematical model predictions show the governing transport process to be temperature gradient induced concentration diffusion, not thermal diffusion. The transport rate is species-dependent, with a greater transport rate of KCl as compared to NaCl. Further work is needed for a better understanding of the implications of temperature gradients for superheater corrosion in boiler environments.


Keywords

Alkali chloride induced corrosion, corrosion, high-temperature corrosion, lab-scale corrosion measurements

Last updated on 2019-15-10 at 03:01