Removal of polychlorinated biphenyls by desulfurization and emissions of polychlorinated biphenyls from sintering plants

Abstract

The influence of desulfurization on polychlorinated biphenyls (PCBs) from sintering plants was investigated. The concentrations of dioxin-like (dl) PCBs, toxic equivalents (TEQs), indicator PCBs, and total tri-to deca-chlorinated PCB homolog groups (∑PCBs) in the flue gases at the desulfurization system inlets were 290-1906 pg m −3 (2.4-18.8 pg World Health Organization (WHO) TEQ m −3 ), 420-2885 pg m −3 , and 6496-22,648 pg m −3 , respectively. Desulfurization reduced the values to 43.3-500 pg m −3 (0.46-9.5 pg WHO-TEQ m −3 ), 183-587 pg m −3 , and 2383-11,639 pg m −3 , respectively. The removed PCBs were adsorbed by gypsum from the flue gas; the PCB concentration distributions at the inlets and outlets and in the gypsum samples were similar. The emission factors were 9.86 ng WHO-TEQ t −1 for the flue gas and 8.37 ng WHO-TEQ t −1 for gypsum. Desulfurization decreased the annual atmospheric PCB emissions from 48.6 to 30.7 g WHO-TEQ, and the estimated annual emissions in gypsum were 8.06 g WHO-TEQ. PCBs in the gypsum have not been effectively eliminated and will probably reenter the environment and in turn become a new source of PCB emission. The PCB concentrations in fly ashes from series-connected electrostatic precipitators clearly increased.

Effects of Desulfurization Processes on Polybrominated Dibenzo-p-dioxin and Dibenzofuran Emissions from Iron Ore Sintering

“…This is the first intensive study of PBDD/F concentrations in stack gases from the inlet and outlet of the desulfurization operation, desulfurization products, and fly ash samples from IOSPs so direct comparisons with previous work is not possible. The PBDD/F removal efficiencies achieved by the desulfurization operations reported here were lower than the PCDD/F removal efficiencies reported in previous field investigations . The PBDD/F concentrations in stack gases were lower than those of PCDD/Fs, however, their concentrations in fly ashes were comparable to those of PCDD/F (54–1200 ng TEQ kg –1 ).…”

Unintentional production of persistent chlorinated and brominated organic pollutants during iron ore sintering processes

“…The PCDD/F TEQ concentrations in the fly ash sampled at the heads and tails of the sintering machines were 2.00-63.1 and 0.25-1.41 ng g −1 , which were slightly higher than values of 0.17-0.88 ng g −1 reported by Wang et al [32]. The dl-PCB concen-trations in the fly ash sampled from the heads and tails of the sintering machines were 1.20-5.49 and 0.10-5.12 ng g −1 , which were comparable to values of 0.49−1.47 ng g −1 reported by Wang et al [33]. The PBDE concentrations in the fly ash sampled from the heads and tails of the sintering machines were 2.61-9.60 and 1.32-5.98 ng g −1 , respectively.…”

Particle size distribution and gas–particle partitioning of polychlorinated biphenyls in the atmosphere in Beijing, China

“…Twelve dl-PCB congeners (CB-77, CB-81, CB-105, CB-114, CB-118, CB-123, CB-126, CB-156, CB-157, CB-167, CB-169, and CB-189), seven indicator PCBs (CB-28, CB-52, CB-101, CB-118, CB-138, CB-153, and CB-180), and tri-to deca-chlorinated PCB homologs (ΣPCBs) were analyzed according to a modified version of US EPA Method 1668B (Wang et al 2015). Each air sample was spiked with 1 ng of 13 C 12 -labeled PCBs internal standard with known concentrations (68B-LCS, Wellington Laboratories, Guelph, Canada) and then extracted with dichloromethane and hexane (1:1, v/v) using an accelerated solvent extractor.…”