Model of fragmentation of limestone particles during thermal shock and calcination in fluidised beds

Jaakko Saastamoinen (Corresponding Author), Toni Pikkarainen, Antti Tourunen, Marko Räsänen, Timo Jäntti

    Research output: Contribution to journalArticleScientificpeer-review

    32 Citations (Scopus)


    Fragmentation of limestone due to thermal shock and calcination in a fluidised bed was studied through experiments and modelling. The time for heating was estimated by model calculations and the time for calcination by measurements. Fragmentation due to thermal shock was carried out by experiments in a CO2 atmosphere in order to prevent the effect of calcination. It was found to be much less than fragmentation due to calcination. Average particle sizes before and after fragmentation are presented for several types of limestone. The effects of particle size and gas composition on the primary fragmentation were studied through experiments. Increasing the fluidisation velocity increased the tendency to fragment. The evolution of the particle size distribution (PSD) of limestone particles due to thermal shock and during calcination (or simultaneous calcination and sulphation) were calculated using a population balance model. Fragmentation due to thermal shock is treated as an instantaneous process. The fragmentation frequency during calcination is presented as exponentially decaying over time. In addition to the final PSD, this model also predicts the PSD during the calcination process. The fragmentation was practically found to end after 10 min. Furthermore, a population balance method to calculate the particle size distribution and amount of limestone in fluidised beds in dynamic and steady state, when feeding history is known, is presented.
    Original languageEnglish
    Pages (from-to)244 - 251
    Number of pages8
    JournalPowder Technology
    Issue number3
    Publication statusPublished - 2008
    MoE publication typeA1 Journal article-refereed


    • fragmentation
    • limestone particles
    • thermal shock
    • calcination
    • modelling


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