Temperature gradient induced boiler deposit densification and intradeposit alkali chloride enrichment

Research output: Chapter in Book/Conference proceedingConference contributionProfessional


Ash deposits cause a wide range of problems in boiler environment, such as enhanced corrosion rate of heat exchangers, decreased thermal flow from flue gas to steam and disruption in the flue gas flow in the boiler.

A laboratory method to study the effect of temperature gradient was applied to study the aging of synthetic S and Cl containing ash deposits with different compositions and grain sizes. The results showcase gas-phase transport of volatile species down the temperature gradient as well as partial melting of deposits. These phenomena are shown to lead to densification of deposits and enrichment of corrosive species on steel surface. The results from the laboratory experiments were applied on a Computational Fluid Dynamics model to simulate ash deposit aging and predict alkali chloride enrichment.

The experimental results show similar morphologies as have been reported in literature to be found in ash deposits collected from biomass fired boilers. From the laboratory and modelling results it is clear that the temperature gradient induced phenomena play a vital role in ash deposit aging, leading to deposit densification and enrichment of volatile corrosive species on the steel surface.
Original languageUndefined/Unknown
Title of host publicationProceedings of the Impacts of fuel quality on power production, the 26th international conference
EditorsF. Hrdlicka
Publication statusPublished - 2016
MoE publication typeD3 Professional conference proceedings


  • Alkali halide
  • boiler deposits

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