The Possibilities of Reduction of Polychlorinated Dibenzo-P-Dioxins and Polychlorinated Dibenzofurans Emission

Wielgosiński, Grzegorz

doi:10.1155/2010/392175

Cited by 21 publications

(12 citation statements)

References 99 publications

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“…Additionally, some studies have shown that coupled deNOx and dioxin destruction SCRs (Wang et al, 2009a), especially V-rich vanadia-tungsta-titania catalysts, are advantageous compared to only deNOx systems in terms of PCDD/F destruction and removal, but are still susceptible to deactivation by high chlorine content in the flue gases (Finocchio et al, 2006). Furthermore, these coupled deNOx and PCDD/F destruction, SCRs can compete with ACI (Finocchio et al, 2006), since the SCR systems destroy PCDD/Fs leading to reduction in PCDD/F mass (Wielgosinski, 2010;Ji et al, 2013).…”

Section: Pcdd/f Emissions From Sintering Plantsmentioning

confidence: 99%

An Overview of PCDD/F Inventories and Emission Factors from Stationary and Mobile Sources: What We Know and What is Missing

Cheruiyot

Lee

Yan

et al. 2016

Aerosol Air Qual. Res.

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This overview attempts to outline what we currently know about the PCDD/F emission inventories and the source categories therein. Besides the best available control techniques, suggestions are offered on how to reduce the PCDD/F emission factors and emission quantity of some important PCDD/F emission sources. The PCDD/F combustion sources can be classified as either stationary or mobile or minimally/uncontrolled combustion sources. The major stationary sources of PCDD/Fs are metal production processes, waste incineration, heat and power plants, and fly ash treatment plant. Crematories, vehicles, residential boilers and stoves are of key concern due to their proximity to residential areas and their relatively lower lying stacks and exhaust gases, which may result in great impact to their surrounding environment.Moreover, we offered our perspectives on how to improve the quality and representative of the PCDD/F emission factors to attain PCDD/F inventories which correspond more to reality. These points of view include: (1) PCDD/F contributions during start-up procedures of MSWIs should be considered, (2) the sampling times of stack flue gases for EAFs and secondary metal smelters should correspond to whole smelting process stages, (3) longer flue gas sampling time should be executed for power plants, (4) direct exhaust samplings from tailpipes for mobile sources, (5) development of an open burn testing facility that can reflect the real open burning conditions, and (6) long-term sampling techniques like AMESA are suggested to used exclusively for the most contributed PCDD/F stationary sources.

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Section: Pcdd/f Emissions From Sintering Plantsmentioning

confidence: 99%

An Overview of PCDD/F Inventories and Emission Factors from Stationary and Mobile Sources: What We Know and What is Missing

Cheruiyot

Lee

Yan

et al. 2016

Aerosol Air Qual. Res.

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“…Dioxins, including polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), have been incorporated into the Annex C compounds of the Stockholm Convention (Stockholm Convention, 2006) due to their chemical properties of stability, lipophilicity and persistence. Therefore, various feasible and effective technologies for the control of dioxins emission are eagerly developing to prevent harmful influence on the environmental and human health (Wielgosiński, 2010;Wang et al, 2009;Chen et al, 2015). Previous studies indicate activated carbon injection technology has an excellent performance on the removal of gaseous PCDD/Fs, and thus has become a widely applied technology in the waste incinerators (Hajizadeh et al, 2011;Kawashima et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Catalytic Decomposition of PCDD/Fs over Nano-TiO2 Based V2O5/CeO2 Catalyst at Low Temperature

Lin

et al. 2016

Aerosol Air Qual. Res.

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Catalytic decomposition of PCDD/Fs (Polychlorinated dibenzo-p-dioxins and furans) over nano-TiO 2 based V 2 O 5 /CeO 2 catalyst is investigated at 180°C based on a stable PCDD/Fs generating system. Step impregnation method is used to prepare the powder catalyst, and catalyst characterization is conducted by XRD and TPR. Effects of oxygen, water vapour and sulphur dioxide on PCDD/Fs destruction are studied in terms of destruction efficiency. Oxygen plays a positive role on PCDD/Fs destruction by accelerating the conversion of V3+ O x and Ce 4+ O x . The destruction efficiencies of PCDD/Fs increase from 67.6% to 77.8% with oxygen contents increasing from 11 vol.% to 21 vol.%. In the absence of oxygen, PCDD/Fs can still be destroyed with destruction efficiency of 33.7% due to the lattice oxygen atoms stored by V 2 O 5 and CeO 2 . Water vapour negatively affects the destruction of PCDD/Fs by competitive adsorption. On the other hand, negative destruction efficiencies of TCDD and TCDF are observed in the presence of water, and the values become lower with water vapour contents increasing. This result demonstrates water vapour facilitates the removal of Cl -present on the catalyst surface. SO 2 inhibits the activity of catalyst by poisoning active sites of catalyst. With SO 2 concentration increasing from 0 to 100 ppm, destruction efficiencies of PCDD/Fs significantly decrease from 67.6% to 51.9%. Finally, catalyst regeneration is also investigated at 180°C in the presence of oxygen. Most of PCDD/Fs residues in the catalyst will be destroyed, and catalyst is regenerated without PCDD/Fs contaminated.

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“…There are three basic mechanisms of their formation described in the literature: high-temperature synthesis (500-700°C) from chlorinated aromatic precursors [7], catalytic synthesis from chlorinated and non-chlorinated precursors and chlorinated compounds taking place at 300-500°C out of the combustion zone [8] and the most important one, the so-called de novo synthesis in which dioxins are formed outside the combustion zone from molecular carbon, carbonated residues from the combustion process, unburned carbon (in the form of dust and soot) and chlorine (both organic and inorganic) in the presence of volatile metals contained in the ash which catalyze the process (eg copper, zinc and aluminum) in the temperature range from 200 to 400°C [9]. There are many methods to reduce emissions of dioxins to the atmosphere which are described in detail in the literature [10,11]. Recently, the authors of many publications focused their attention on the reduction of dioxin emissions by reducing their formation according to the de novo mechanism.…”

Section: Introductionmentioning

confidence: 99%

Effect of selected additions on de novo synthesis of polychlorinated dioxins and furans

Wielgosiński

Namiecińska

Łechtańska

et al. 2016

Ecological Chemistry and Engineering S

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Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans are generally considered the most dangerous chemical substances known to man. Although they have never been the product of purposeful human activity, yet they are formed in many chemical and virtually all thermal processes. Research on the occurrence of dioxins in the environment, their release into the environment, ways of formation and methods of reducing their emissions lasts since the late seventies of the last century. Currently, we know three basic pathways of dioxins formation in thermal processes, the most important of them being the so called de novo synthesis which occurs outside the combustion zone at 200-400°C in the presence of catalysts (eg copper) and oxygen from the products of incomplete combustion including carbon black and chlorine or chlorinated compounds. It is well known that some metals like copper catalyze the de novo synthesis, while others decompose dioxins and furans formed previously. The formation of dioxins resulting from the de novo synthesis was studied through analysis of the effect of the type of metal on the course of the de novo synthesis. The influence of the addition of sulfur, nitrogen and alkali metals on this synthesis was also examined because some reports in the literature refer to inhibitory effect of these elements.

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The Possibilities of Reduction of Polychlorinated Dibenzo-P-Dioxins and Polychlorinated Dibenzofurans Emission

Cited by 21 publications

References 99 publications

An Overview of PCDD/F Inventories and Emission Factors from Stationary and Mobile Sources: What We Know and What is Missing

An Overview of PCDD/F Inventories and Emission Factors from Stationary and Mobile Sources: What We Know and What is Missing

Catalytic Decomposition of PCDD/Fs over Nano-TiO2 Based V2O5/CeO2 Catalyst at Low Temperature

Effect of selected additions on de novo synthesis of polychlorinated dioxins and furans

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