Improved temperature measurements of burning char and coal particles using an FT-IR spectrometer

Sønnik Clausen, L.H. Sørensen

    Research output: Contribution to journalJournal articleResearchpeer-review

    Abstract

    A novel method for temperature measurements on individual burning char and coal particles with an FT-IR spectrometer has been developed. The technique is demonstrated for monitoring emission spectra of individual moving particles that require a few milliseconds to pass the field of view of a conventional scanning FT-IR spectrometer. The accurate particle surface temperature is calculated from a best match of the measured emission spectrum to a detailed physical radiance model spectrum. The technique is applied to measure the surface temperature of 90-125 μm particles with temperatures from 1000 to 2200 K in an entrained flow reactor. A one-temperature calibration of the FT-IR spectrometer is sufficient for accurate measurements throughout a broad temperature range. Background radiation and a fluctuating particle feeding rate are handled by subtraction of two successive measurements. The single-particle emission spectra are useful for testing the assumptions about particle emissivity as a function of wavelength. The findings in the present work justify the graybody assumption for the burning char particles as well as the burning coal particles. Under sooting conditions particle temperature errors of about 300 K were observed. The burn-off for four coal samples is analyzed and compared with particle temperatures at 1, 3, 6, 12, and 21 vol % oxygen. In addition to giving important information on the modeling of the combustion process, the particle temperature measurements and the burn-off give information that can be used for ranking of coal samples with respect to reactivity.
    Original languageEnglish
    JournalEnergy Fuels
    Volume10
    Issue number5
    Pages (from-to)1133-1141
    DOIs
    Publication statusPublished - 1996

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