Modelling the behaviour of ash in a BFB boiler by combining CFD and thermodynamic equilibrium calculations

Johanna Nieminen, Cyril Bajamundi

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific


    Inorganic compounds from molten and vaporised ash in biomass combustion can cause slagging, fouling and corrosion in the boiler. In this study, the behaviour of ash is modelled by combining CFD and thermodynamic equilibrium calculations. This was done by linking the CFD code Ansys Fluent and the thermodynamic phase equilibrium calculation code ChemApp. Two test cases were calculated: a BFB boiler of 107 MWth burning bark and the same boiler burning a mixture of bark and sludge. The model was used to predict vaporisation, melting, gas phase reactions and condensation of the ash in the boiler. In the test cases, the model predicted a risk of slagging as well as fouling and corrosion for bark, while during the co-combustion of bark and sludge the risks were predicted to be somewhat lower.
    Original languageEnglish
    Title of host publicationProceedings of the Nordic Flame Days 2015
    PublisherInternational Flame Research Foundation IFRF
    Publication statusPublished - 2015
    MoE publication typeB3 Non-refereed article in conference proceedings
    EventNordic Flame Days 2015 - Copenhagen, Denmark
    Duration: 6 Oct 20157 Oct 2015


    ConferenceNordic Flame Days 2015


    • combustion
    • CFD
    • slagging
    • fouling
    • corrosion


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