DETERMINATION OF SULFUR GASES FROM VELENJE COAL STOCKPILE

Janez Kozinc,^a Mireille Treeby,^a and Lucija Zupančič–Kralj^b
a ERICo Velenje, Institute for Ecological Research, Koroška 58, 3320-SI Velenje, Slovenia
^b Faculty of Chemistry & Chemical Technology, University of Ljubljana, Aškerčeva 5, 1000-SI Ljubljana, Slovenia

Abstract

Dimethyl sulfide (DMS), carbonyl sulfide (COS) and carbon disulfide (CS₂) were detected at the Velenje coal stockpile. The gases were collected in a sampling tent placed on the stockpile. Several sampling and measuring techniques were tested for their determination. For direct analysis and solid phase micro extraction (SPME) the gases were pumped from the tent into Tedlar bags, while for cryogenic trapping the gas was pumped through a cryo-trap from the tent. The analyses were performed by gas chromatographs, equipped with a flame photometric detector (FPD) and a mass selective detector (MSD).

It was found that direct gas analysis by GC-MSD is the method of choice for determination of the gases in the ppbv concentration level. DMS was rarely quantified, while concentrations of COS and CS₂ were temperature dependant. It was confirmed that oxygen was necessary for the formation of COS and CS₂. The source of COS and CS₂ is probably oxidation of pyrite in coal, which was determined by X-ray spectroscopy.

Key words: sulfur gases, oxidation of pyrite, coal stockpile, SPME