RFA und ICP OES: Vergleich anhand eines Ringversuches und Nutzen für die Kraftwerkschemie

Atomic absorption spectrometry (AAS) and inductive coupled plasma analysis technique (ICP OES) will be used for determination of macro and trace elements in power plant laboratories. Beside by x-ray fluorescence analysis (XRF), chiefly the wave disperse technique (WDXRF) as against the energy disperse technique (EDXRF) is used for determination. In this paper a comparison of the techniques will be made on the basis of round robin data and latest developments of XRF, the energy disperse with polarized x-radiation exited XRF (EDPRF), will be presented. In the round robins carried out three coal ashes of imported coals were analysed for macro elements and two fly ashes, one from dry bottom firing and one from slag tap firing, were analysed for trace elements. The new analysis technique, the EDPRF, could thereby show its efficiency. The influence on the combustion and on downstream plant components will be described by element-specific results of investigations at imported coals. One example will show the relationship between the fusibility of fuel ash and calcium/magnesium oxide content of coal and will compare this with the typical fusibility of hard coal ash from the Ruhr area. Another example will discuss the distribution of cadmium along the flue gas path during coal firing without and with residue addition. At last it will be referred to quality assurance which is the prior condition for analysis, i.e. its benefit.