A fundamental study on the change in composition of fireside deposits with time in kraft recovery boilers

A4 Conference proceedings


Internal Authors/Editors


Publication Details

List of Authors: Jonne Niemi, Daniel Lindberg, Markus Engblom, Honghi Tran
Publication year: 2017
Publisher: Pulp and Paper Technical Association of Canada
Book title: Proceedings International Chemical Recovery Conference 2017
ISBN: 9781772890037


Abstract

Accumulation of fireside deposits on heat transfer tube surfaces is a persistent problem in the kraft recovery boiler operation. In a given boiler, the deposit composition varies with location. Even at a given location, the composition varies across the deposit layer. This study systematically studies what makes the deposit compositions heterogeneous. An entrained flow reactor with an air-cooled probe was used to collect and age synthetic deposits. Results confirm NaCl and KCl migration towards colder temperatures due to evaporation-condensation. In addition, liquid phase movement towards the colder temperatures was confirmed. High alkali chloride melt penetrates the deposit and precipitates in colder temperatures leading to enrichment of corrosive alkali chloride species close to the steel. The results imply that liquid phase movement within recovery boiler deposits can accelerate corrosion.


Keywords

aging, composition, molten salt, recovery boiler

Last updated on 2019-20-10 at 03:45