Relative rates of formation of polychlorinated dioxins and furans from precursor and de novo reactions

Altwicker, Elmar R.

doi:10.1016/0045-6535(96)00312-8

Cited by 78 publications

(38 citation statements)

References 14 publications

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“…The decisive role of chlorophenols (CPs) and chlorobenzenes (CBs) could hardly be challenged in PCDD/Fs formation (Altwicker, 1996;Milligan and Altwicker, 1996;Weber and Hagenmaier, 1999;Iino et al, 2000;Catherine and Dellinger, 2003). These classes of compounds were always found together with PCDD/Fs in the effluents of incinerators and have been suggested as indicator compounds.…”

Section: Introductionmentioning

confidence: 99%

Inhibition of PCDD/Fs formation from dioxin precursors by calcium oxide

et al. 2005

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Research aimed at understanding the inhibition effect of CaO on polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) formation form dioxins precursors, such as chlorophenols (CPs) and chlorobenzenes (CBs). The results indicated that a clear dioxin inhibition effect occurred both in open and sealed system when CaO was used. In the open system, PCDDs were the main congeners and the inhibition efficiency was all over 99% in the experiments. In the experiments with CaO, less than 0.1% of the initial PCP was detected in the absorption tube and only about 1% of the initial PCP was examined as calcium pentachlorophenate in the reaction tube. In the sealed system, the inhibition efficiency was over 90% at temperature range between 280 and 450°C when PCP was used as model precursor. When HCB and 2,3,4,5-T 4 CP replaced PCP, significant inhibition effect was also observed. As CaO has the advantageous properties of non-toxicity and non-volatile nature, it is our hope that the result will contribute to the development of a new technique to cope with the problem of dioxin pollution in MWIs.

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Section: Introductionmentioning

confidence: 99%

Inhibition of PCDD/Fs formation from dioxin precursors by calcium oxide

et al. 2005

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“…Various PCDD/F congeners, both simple and complex (Jarmohamed and Mulder, 1994;Iino et al, 1999;Tame et al, 2007;Hajizadeh et al, 2011;Cheruiyot et al, 2015), can be suitable precursors, however, monocyclic aromatic compounds e.g., (chloro) phenols and (chloro) benzenes have been shown to be the most direct routes to the formation of PCDD/Fs (Altwicker and Milligan, 1993;Luijk et al, 1994;Altwicker, 1996). The formation reactions from these monocyclic aromatic compounds involve degradation of these precursors and the rearrangement of their structures.…”

Section: Formation and Decomposition Mechanisms Of Pcdd/fsmentioning

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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“…Heterogeneous formation of PCDD/Fs on the surface of fly ash particles is generally accepted to be much more important than homogeneous formation in gas-phase. Two formation pathways relevant to incinerator conditions have been identified to generate PCDD/Fs on heterogeneous formation: (i) reactions between chlorinated aromatic precursors previously formed in gas-phase and (ii) de novo synthesis, in which the carbon present in the solid phase material of fly ashes reacts in the presence of chlorine, oxygen and hydrogen to give chlorinated aromatic compounds, both PCDD/Fs or precursors [27][28][29]. Reactions are catalysed by metals, such as Cu, and principally occur in the post-combustion zone of incinerators where temperatures ranging 250-450 8C favour formation [30].…”

Section: U N C O R R E C T E D P R O O Fmentioning

confidence: 99%

Semivolatile and volatile compounds from the pyrolysis and combustion of polyvinyl chloride

Aracil

Font

Conesa

2005

Journal of Analytical and Applied Pyrolysis

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Emissions evolved from the pyrolysis and combustion of poly(vinyl chloride) were studied at four different temperatures (500, 700, 850 and 1000 8C) in a horizontal laboratory tubular quartz reactor in order to analyse the influence of both temperature and reaction atmosphere on the final products from thermal and oxidative reactions. It was observed that the CO 2 /CO ratio increased with temperature. Methane was the only light hydrocarbon whose yield increased with temperature up to 1000 8C. Benzene was rather stable at high temperatures, but in general, combustion at temperatures above 500 8C was enough to destroy light hydrocarbons. Semivolatile hydrocarbons were collected in XAD-2 resin and more than 160 compounds were detected. Trends on polyaromatic hydrocarbon (PAH) yields showed that most had a maximum at 850 8C in pyrolysis, but naphthalene at 700 8C. Formation of chlorinated aromatics was detected. A detailed analysis of all isomers of chlorobenzenes and chlorophenols was performed. Both of them reached higher total yields in combustion runs, the first ones having a maximum at 700 8C and the latter at 500 8C. Pyrolysis and combustion runs at 850 8C were conducted to study the formation of polychlorodibenzo-p-dioxins (PCDDs) and polychlorodibenzofurans (PCDFs). There was more than 20-fold increase in total yields from pyrolysis to combustion, and PCDF yields represented in each case about 10 times PCDD yields. #

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Relative rates of formation of polychlorinated dioxins and furans from precursor and de novo reactions

Cited by 78 publications

References 14 publications

Inhibition of PCDD/Fs formation from dioxin precursors by calcium oxide

Inhibition of PCDD/Fs formation from dioxin precursors by calcium oxide

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

Semivolatile and volatile compounds from the pyrolysis and combustion of polyvinyl chloride

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