Mono- to Octachlorinated Polychlorinated Dibenzo-p-dioxin and Dibenzofuran Emissions from Sintering Plants Synergistically Controlled by the Desulfurization Process

Abstract

ABSTRACT:The influence of desulfurization systems in sintering plants on polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) concentrations, profiles, and emission factors was studied. Mono-to tri-CDD/Fs and tetra-to octa-CDD/F concentrations were 4.4 ± 2.3 and 10.5 ± 8.3 ng m −3, respectively, at the inlets and 0.87 ± 0.48 and 0.47 ± 0.22 ng m −3 , respectively, after desulfurization. The toxic equivalents (TEQs) were 0.95 ± 0.093 and 0.51 ± 0.040 ng of I-TEQ m −3 at the inlets and after desulfurization, respectively. The congener profiles and homologue distributions were dominated by 2-MoCDF and MoCDF, respectively. The PCDD/F removal efficiencies achieved by desulfurization increased as the chlorination level increased. The PCDD/Fs became adsorbed to gypsum. Annual mono-to tri-CDD/Fs PCDD/F and TEQ (tetra-to octa-CDD/F) emission factors for flue gas and gypsum between 2003 and 2012 were determined. The total amounts of mono-to tri-CDD/Fs emitted in flue gas and gypsum between 2003 and 2012 were 10.7 and 10.2 kg, respectively. The total TEQs emitted in flue gas and gypsum between 2003 and 2012 were estimated to be 15486 and 1878 g of I-TEQ, respectively. PCDD/Fs adsorbed to gypsum are not effectively eliminated. The PCDD/F concentrations increased as the fly ash surface area increased moving through the electrostatic precipitator stages.

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

“…The PCDD/F, dl-PCB, PCN, and PBDE concentrations in the fly ash samples from heads and tails of the SNT machines sampled in this study, as well as values from the literature are shown in Table S2. 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].…”

Analysis and modeling of the Z‐pin insertion in prepreg based on contact mechanism

“…Figure 5 shows the insertion force vs. displacement curves for different lay-up sequences. It can be seen that a typical two-phase penetration mechanic 19,20 is shown for both unidirectional prepreg and cross-ply prepreg. In the compression phase (Phase I), the prepreg is in the elastic loading stage when the Z-pin tip is pressed against the prepreg surface.…”

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

“…Desulfurization operations have been found to remove various other pollutants, including dust and NOx, alongside SO 2 . We previously reported that desulfurization operations also remove PCDD/Fs from IOSPs’ stack gases . However, insofar as we are aware, no systematic study of the removal of PBDD/Fs from IOSPs’ stack gases by desulfurization operations has yet been described.…”

“…Approximately 40% of global iron ore sintering (more than in any other country) occurs in China where the industry includes many small, energy-inefficient IOSPs that emit relatively large amounts of pollutants. Eliminating old, small, inefficient IOSPs and encouraging the use of more advanced technologies indirectly decreases CO 2 , SO 2 , NO X , and PCDD/F emissions. − However, the effects of these measures on decreasing PBDD/F emissions in China have not been estimated.…”