Indicator parameters for PCDD/PCDF from electric arc furnaces
Öberg, T.
Presentation at the 8th Scandinavian Symposium on Chemometrics, Mariehamn,
Finland, June 14-18, 2003.
Abstract
The unintentional formation and release of persistent organic pollutants (POP)
from industrial sources is of environmental concern and efforts are now made to
reduce these emissions [1]. The emissions of chlorinated trace organics from
electric arc furnaces (EAF) have been monitored on a regular basis in Sweden
since the 1980s. Most analyses have encompassed not only polychlorinated
dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF), but also chlorinated
benzenes and phenols. Emissions of PCDD/PCDF from municipal solid waste
incinerators (MSWI) can be modelled and predicted from analyses of chlorinated
benzenes and phenols, which are suspected to be precursors in the formation
process. The purpose of this investigation was to extend and update previously
reported models with new samples from EAF, to describe the main sources of
variation, and to compare multivariate calibration with univariate regression.
The measurement data consisted of 27 samples collected between 1987 and 2002 and
analysed by two different laboratories. A general multivariate calibration model
was able to describe 97% of the variation in the TEQ (toxic equivalent quantity)
value over five orders of magnitude. Univariate regression models cannot account
for changes in the congener pattern and thus gave a poorer performance. In
plant-specific applications the univariate approach did, however perform equally
well. It was therefore concluded that both multivariate and univariate
regression models can be used in process optimisation studies, but that
multivariate models are better suited for emission monitoring and evaluation of
flue gas cleaning efficiencies.
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