Bulgarian lignite combustion as a source of polycyclic aromatic compounds

This paper describes state of the art for isolation and determination of polycyclic aromatic hydrocarbons (PAH) from Maritza East lignites combustion. Two sets of experiments were performed: (i) PAH in flue gases from fluidized bed combustion (FBC) in laboratory scale installation determination by fluorescence spectroscopy in synchronous mode and GC-MS; (ii) analysis of PAH in organic extracts from combustion wastes of thermal power plants under exploration. By a sequence of 5 traps and extensive application of spectral and chromatographic techniques the isolation and characterisation of PAH in FBC flue gases was possible. The total sum of emission, expressed in microg/kg, as well as profile of PAH distribution were determined. The sampled mixture of FBC was composed by PAH, their alkylated, phenylated homologues and heteroatom containing counterparts with dominance of three/four cyclic aromatic compounds. Respectively, relative carcinogenic potency value (TEQEPA) of trapped PAHs compared to Benzo(a)pyrene with TEFEPA =1 was not high. By mass spectroscopy and application of deuterated internal standards for quantitative interpretation 17 PAH, some of them in the list of USEPA for priority pollutants with expressed carcinogenic/mutagenic potential, were identified. The total contents of PAH for waste material under study were as follows: - 477 microg/kg with TEQEPA factor 12.95 for fly ash; - and, 707 microg/kg with TEQEPA factor 1.06 for slag. (author)