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

Jonne Niemi, Daniel Lindberg, Markus Engblom, Honghi Tran

Research output: Chapter in Book/Conference proceedingConference contributionScientificpeer-review


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.

Original languageUndefined/Unknown
Title of host publicationProceedings International Chemical Recovery Conference 2017
PublisherPulp and Paper Technical Association of Canada
ISBN (Print)9781772890037
Publication statusPublished - 2017
MoE publication typeA4 Article in a conference publication
EventInternational Chemical Recovery Conference (ICRC) - International Chemical Recovery Conference, ICRC 2017
Duration: 24 May 201726 May 2017


ConferenceInternational Chemical Recovery Conference (ICRC)


  • aging
  • composition
  • molten salt
  • recovery boiler

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