Qualitative Discrimination Analysis of Coals Based on Their Laser-Induced Breakdown Spectra

Abstract

Six different coal samples (anthracite, Czech brown coal, Polish brown coal, lignite, graphite, and Pećs-vasas brown coal) were studied by using laser-induced breakdown spectroscopy (LIBS) in order to assess its capability for use in coal quality control. The spectral features of the coals as well as their correlation with the results of proximate analysis was investigated. The second part of the study deals with the classification (qualitative discrimination analysis) of coals based on their visible-range LIBS spectra using various statistical methods. Canonical linear discriminant analysis was found to be the most efficient; using five canonical variables and after reducing the spectra to 18 variables, the achieved classification accuracy was 95.33% according to the cross-validation test of the model. The described results indicate that LIBS data can be efficiently used for the quality control of coals and thus can also contribute to the indirect control of the combustion process.

Qualitative discrimination of coal aerosols by using the statistical evaluation of laser-induced breakdown spectroscopy data

“…The statistical functions and methods used in the present work are known in the literature and we also described them in detail in our earlier qualitative discrimination studies performed on other sample types (e.g. [16,31,34]), so here we only briefly outline their concept.…”

“…Portable and stand-off LIBS instrumentation is also available commercially, thus this technique is very suitable for field measurements in many scenarios including industrial, environmental or safety-related analytical tasks [14,15]. Industrial applications also include coal and fly ash analysis [16][17][18], as well as aerosol analysis in general.…”

“…Mukherjee and Cheng investigated how different mass loadings in the plasma induce matrix effects during the quantitative analysis of carbonaceous aerosols [12]. At the same time, no studies have addressed the on-line, qualitative discrimination of coal aerosols according to their source coal type so far, although the potential of LIBS for the classification/identification of samples has already been successfully demonstrated on various samples, for example in microbiological [25][26][27], medical [28,29], industrial [16,30,31] or forensic [32][33][34] applications.…”

Analitikai módszerek fejlesztése folyadék és szilárd minták LIBS vizsgálatára

“…A bemutatott előzetes eredmények alapján a tömbi szenek megkülönböztetésére mind az egyszerű komparatív függvények, mind a fejlettebb statisztikai kiértékelési módok is eredményesen használhatók, azonban az aeroszolok esetében csak a fejlettebb statisztikai módszerekkel lehet sikeresen megvalósítani a kvalitatív diszkriminációs analízist [170,171].…”

“…A tárgylemezek szokásos, 25 x 75 mm mérete is jól illeszkedik a 25 mm átmérőjű membránok méretéhez, így két membrán egymás mellett jól elfér a cellában egyszerre. Ezt a mintakamrát sikerrel alkalmaztuk urán, tórium és cézium meghatározására különböző mátrixok esetében [170].…”