Comparing reaction orders of anthracite chars with bituminous coal chars at high temperature oxidation conditions

Oskar Karlström, Anders Brink, E Biagini, Mikko Hupa, L Tognotti

    Research output: Contribution to journalArticleScientificpeer-review

    22 Citations (Scopus)

    Abstract

    The influence of concentration of oxygen on the oxidation rates of 5 anthracite chars is investigated at gas temperatures ranging from 1223 K to 1673 K. Reaction orders and kinetic parameters are determined with a multivariable optimization method in which modeled burnout profiles are fitted to experimental burnout profiles from a 4 m isothermal plug flow reactor operating at industrially realistic heating rates, i.e., 10(4) - 10(5) K/s. The determined reaction orders are compared to reaction orders of 10 bituminous coal chars investigated at similar conditions in a previous study. The results show that the optimized reaction order of the anthracite chars is zero, while the reaction order of the bituminous coal char is one. The difference in the reaction orders cannot be explained by using the two semi-global oxidation reactions: C(O) + O-2 > CO/CO2 and C(O) > CO. However, by also considering 2C(O) > CO2 + C as a possible reaction step, the reaction order difference between the anthracite chars and the bituminous coal chars can be explained. In addition, a first attempt to apply the same multivariable optimization method to determine the reaction order for a biomass char is presented.
    Original languageUndefined/Unknown
    Pages (from-to)2427–2434
    Number of pages8
    JournalProceedings of the Combustion Institute
    Volume34
    Issue number2
    DOIs
    Publication statusPublished - 2013
    MoE publication typeA1 Journal article-refereed

    Keywords

    • Coal chars
    • Kinetics
    • Reaction order

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