Effects of calcium-based sorbents on PCDD/F formation from pentachlorophenol combustion process

Lu, Shengyong; Chen, T.; Yan, Jian Hua; Li, X.D.; Ni, Yuguo; Cen, Ke Fa

doi:10.1016/j.jhazmat.2007.05.012

Cited by 21 publications

(18 citation statements)

References 32 publications

(25 reference statements)

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“…A large number of studies have been conducted regarding the possible suppressing effects of CaCO 3 and CaO on the formation of PCDD/Fs because of the ability of calcium containing compounds to bind to hydrochloric acid, thus avoiding a fraction of later chlorination and the consequent formation of PCDD/Fs (Jozewicz and Gullett, 1995;Shemwell et al, 2001;Lu et al, 2007). For example, 1033 PCDD/F formation was strongly suppressed by CaCO 3 during the incineration of polyvinyl chloride (PVC); also the HCl concentration in the flue gas significantly decreased (Sun et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Suppression of PCDD/Fs by Raw Meal in Cement Kilns

Lin

Ji²,

Zhan

et al. 2018

Aerosol Air Qual. Res.

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Raw meal of the cement production process could probably suppress the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). In this study, these suppression effects were studied and compared during the co-processing of municipal solid waste (MSW) with conventional feed materials such as pure CaCO 3 , and pure CaO. A top suppression efficiency of 96% was achieved for a ratio of MSW to raw meal of 1:15. Moreover, NaCl and CuCl 2 were added to the mix of feed material and MSW, to reveal the impact of additional chlorine and cations on PCDD/F formation. Similarly, the raw meal was mixed with the kiln dust to investigate possible suppression effects of those PCDD/Fs formed through the precursor or the de novo synthesis at a temperature of 350°C. The raw meal suppressed the formation of PCDD/Fs from kiln dust. Furthermore, the raw meal could not suppress the formation of PCDD/Fs on mixtures of kiln dust and NaCl or CuCl 2 , which could be associated with a potential increase in the formation effects of PCDD/Fs on the raw meal. The results can help in potential decision-making on the applicability of certain cement kilns on the co-processing of MSW containing high levels of Cl and Cu.

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Section: Introductionmentioning

confidence: 99%

Suppression of PCDD/Fs by Raw Meal in Cement Kilns

Lin

Ji²,

Zhan

et al. 2018

Aerosol Air Qual. Res.

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“…In particular, the I-TEQ values for the 5%, 10% and 20% urea reaction systems (i.e., 0.43, 0.087, and 0.049 ng/mg, respectively) were 195-1714 times lower than that of the PCP blank reaction system (i.e., 83.99 ng/mg). Lu et al [14] reported that I-TEQ levels of adding CaO inhibitor were 29 times lower than that of no sorbent on PCP forming PCDD/Fs. Meanwhile, the I-TEQ of formed 2,3,7,8-PCDD/Fs in mixed urea/CaO reaction system was compared to that of corresponding combination of urea alone and CaO alone according to the calculation from Table 1 above.…”

Section: Resultsmentioning

confidence: 99%

“…Various chemical inhibitors for reducing PCDD/F formation have been tested on both laboratory-and pilot-plant-scales. The alkali earth metal oxides (CaO, BaO and MgO) have been reported to suppress PCDD/F formation from PCP in a laboratory-scale reactor [5,14]. However, the suppressing efficiencies of them is CaO ≈ BaO > MgO.…”

Section: Introductionmentioning

confidence: 99%

Synergetic inhibition of PCDD/F formation from pentachlorophenol by mixtures of urea and calcium oxide

et al. 2016

Journal of Hazardous Materials

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h i g h l i g h t s• Mixed CaO/urea have a synergetic inhibition effect for PCDD/Fs formation from PCP.• 5-20% urea reaction systems obtained the better synergetic inhibition effect.• 2,3,7,8-PCDD congeners were the dominant products in eight reaction systems.• Intermediates could promote the acid-base reaction to realize synergetic inhibition. a r t i c l e i n f o b s t r a c tChlorophenols are structurally similar to PCDD/Fs and have been considered as highly potential precursors for PCDD/Fs formation. The suppressing effects of PCDD/F formation from pentachlorophenol (PCP) were investigated on various mass ratios of CaO and urea. The total concentration of 2,3,7,8-PCDD/Fs, mostly dominated by OCDD, was determined to be 48.58-10186 ng/mg in inhibitor-reaction systems, being much lower than that in blank reaction system (75654 ng/mg). Interestingly, compared with pure CaO and urea reaction system, the concentration and TEQ of formed 2,3,7,8-PCDD/Fs in mixed urea/CaO reaction system were lower, especially with 5-20% urea reaction systems being respectively at decrease by 96.5-99.4% and 99.2-99.7%. The suppression efficiency of TEQ in 5-20% urea reaction systems could be always approximately 100% under 250-350• C. These results suggested that mixed inhibitors, especially 5-20% urea inhibitors, have a synergetic inhibition effect for PCDD/Fs formation from PCP. Mixed inhibitor generated several intermediates, involving CO 2 , H 2 O, NH 3 , Ca(OH) 2 , CaCO 3 , HNCO, biuret and ammelide. The complex between PCP and Ca, N-doped species, lower chlorinated phenols and benzenediol, and organic acids were also determined. Synergetic inhibition mechanism may be attributed to accelerated facilitation of acid-base reaction and N doping. The decomposition of PCP itself also contributes to prevent PCDD/Fs formation.

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“…It has been reported that the addition of CaO and urea to a PCDD/F formation system signicantly decreases PCDD/Fs emissions. [57][58][59] This was due to the basicity of the added materials. Similarly, the amount of PCDFs formed was signicantly lower in the NiFe 2 O 4 reaction system when compared with that in the CB-209 blank reaction system, although NiFe 2 O 4 is not basic.…”

Section: Origin Of Pcdf Formation Inhibition By Nife 2 Omentioning

confidence: 99%

Effect of NiFe2O4 on PCDF byproducts formation during thermal degradation of decachlorobiphenyl

Huang

Liu

et al. 2014

RSC Adv.

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Relative to the catalyst-free reaction system, the concentration and total toxic equivalent values of 2,3,7,8-PCDFs decreased by 24.1-99.7% and 86-98.4%, respectively, in the NiFe 2 O 4 catalyst system, while initial increases by 744.5% and 426.3%, respectively, followed by reduction up to 81.6% and 90.7%, respectively, were observed in the Fe 2 O 3 catalyst system. Current findings indicate that NiFe 2 O 4 hindered PCDF formation, which was attributed to its chemical structural stability and high activity towards degradation of biphenyl-like constituents in PCBs.

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Effects of calcium-based sorbents on PCDD/F formation from pentachlorophenol combustion process

Cited by 21 publications

References 32 publications

Suppression of PCDD/Fs by Raw Meal in Cement Kilns

Suppression of PCDD/Fs by Raw Meal in Cement Kilns

Synergetic inhibition of PCDD/F formation from pentachlorophenol by mixtures of urea and calcium oxide

Effect of NiFe2O4 on PCDF byproducts formation during thermal degradation of decachlorobiphenyl

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