Technologies for dioxin control at municipal waste combustors (MWC) beyond good combustion practices (GCP) and dry scrubbers / fabric filters (DS/FF)

Hahn, J.

doi:10.1016/0045-6535(92)90479-b

Cited by 8 publications

(4 citation statements)

References 3 publications

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“…These groups of substances cannot be separated by conventional gas cleanup processes. A suitable process is the adsorption by carbon-containing adsorbents such as activated carbon, lignite, or coke (5,(7)(8)(9)(10)(11)(12)(13) applied either through the injection of an adsorbent and subsequent removal by filtration or in a separate moving/fixed-bed adsorber at the end of the flue gas cleaning trail. The simplest technique is the injection of pulverized sorbents in the flue gas, thus avoiding high investment costs of separate adsorption systems.…”

Section: Introductionmentioning

confidence: 99%

Entrained-Phase Adsorption of PCDD/F from Incinerator Flue Gases

Everaert

Baeyens

Degrève

2003

Environ. Sci. Technol.

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The emission abatement of polychlorinated dioxins and furans (PCDD/F) issued from municipal solid waste incineration (MSWI) is growing in importance because of more stringent emission standards and general health concern. These substances cannot be separated by conventional gas cleanup processes. They are successfully removed through adsorption onto carbonaceous materials, and the entrained-phase injection of pulverized adsorbents in the flue gas, followed by high-efficiency separation, is widely applied. Operating conditions and results obtained in Flemish MSWIs are given. The results illustrate the excellent overall removal efficiency: the regulation limit of 0.1 ng TEO/Nm3 dry gas at 11% O2 can be achieved. Furans are adsorbed to a slightly higher extent than the dioxins. The PCDD/F removal by carbonaceous adsorbents is thereafter modeled from first principles for the contribution of both entrained-phase (eta1) and cake filtration (eta2) to the overall efficiency (etaT), with dominant parameters being the operating temperature, the dosage and activity of adsorbent, and the fraction of adsorbent in the filter cake. Application of the model equations and comparison of measured and predicted overall efficiencies for the Flemish MSWIs demonstrate the validity of the model, which enables the MSWI operators both to predict the adsorption efficiencies for combinations of major operating parameters and to assess the sensitivity of the process to varying operating conditions. Finally, some practical difficulties encountered with the entrained-phase adsorption are discussed.

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Section: Introductionmentioning

confidence: 99%

Entrained-Phase Adsorption of PCDD/F from Incinerator Flue Gases

Everaert

Baeyens

Degrève

2003

Environ. Sci. Technol.

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“…The model predictions are however meaningful and enable the MSWI operators to predict the adsorption efficiencies for any combination of operating parameters. Although literature data on overall efficiencies are also available3, 17, 18, 24, 25 and range from 95 to >99%, it is impossible to compare them with the model predictions due to the lack of values for the operating conditions. The experimental results of Ruegg and Sigg25 fit the measured results for f A (3%) and f s (3.0–4.7%).…”

Section: Application Of the Design Equationsmentioning

confidence: 99%

Adsorption of dioxins and furans from flue gases in an entrained flow or fixed/moving bed reactor

Everaert

Baeyens

Creemers

2003

J of Chemical Tech & Biotech

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Under certain operating conditions, polychlorinated dioxins and furans occur in the flue gases of thermal processing plants. Current EU Directives limit the concentration of these emissions to less than 0.1 ng toxicity equivalents (TEQ) per standard cubic metre of dry gas at 11 vol% O 2 . These Directives have been included in the emission regulations of most of the EU countries. Dioxins and furans are not particular to incinerators; they can also originate from metallurgical and other thermal processes when these are operated under unfavourable conditions. Adsorption methods employing non-flammable carbonaceous adsorbents (activated carbon, lignite) are particularly well suited for removing PCDD/Fs. For adsorption, which requires the sorbent to be brought in contact with the gas to be cleaned, various processes are currently available, ie classical adsorption in moving/fixed bed filters or the technique of adsorption in an entrained dust cloud with a downstream fabric filter or electrostatic precipitator to remove the spent sorbent from the waste gas (entrained process). The paper will firstly assess both adsorption concepts; it will then use results obtained from operational tests in incineration plants for municipal and industrial waste to describe the efficiency of the dioxinsorption in an entrained bed (pneumatic transport of pulverized adsorbent) and a fixed/moving bed (granular adsorbent). Variations in the dosing rate and the use of different adsorbents, as well as the operating temperature, identify the selection criteria for determining the process-engineering optimum for flue gas cleaning. The paper will demonstrate that the PCDD/F emissions can be reduced to below 0.1 ng TEQ Nm À3 and will identify the operating conditions required to achieve this standard.

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“…Removal of pollutants by adsorption is one of the well-known processes. Fabric bag filter, activated carbon tower, and, recently, wet adsorption techniques have been applied in the flue gas treatment facilities of municipal solid waste incinerators (10,11,14,49,50). In particular, a fabric bag filter house with activated carbon injection is popular for the removal of PCDD/F (2,11,14).…”

Section: Prediction Modelmentioning

confidence: 99%

Evaluation of Polychlorinated Dibenzo-p-dioxin/Dibenzofuran (PCDD/F) Emission in Municipal Solid Waste Incinerators

Shin

Choi

et al. 1999

Environ. Sci. Technol.

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This paper summarizes an engineering approach taken for 10 commercial MSW incinerators to formulate a basis for PCDD/F emission reduction schemes and to interpret the measurement results before and after the plant modifications of moderate scale. Control strategy of PCDD/F emission from the operating incinerators can be established on the basis of the interpretation of reliable measurements as well as understanding of the formation/destruction processes. The fate of PCDD/F is known to be influenced by the flue gas subprocesses: the initial formation/ oxidation in the combustion chamber, reformation through synthesis, removal by adsorption, and catalytic destruction. A simplified model is proposed for PCDD/F level at various stages of the flue gas, basically integrating the reaction kinetic rates at the corresponding state. Since the kinetic rate is dependent on temperature, time-temperature history of the flue gas is considered as the important input data. Using the plant design and operating conditions, this global prediction model calculates the PCDD/F level not only at the stack but also at the process midstream. The model predictions are discussed along with measurement results from the different design of incinerator plants.

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Technologies for dioxin control at municipal waste combustors (MWC) beyond good combustion practices (GCP) and dry scrubbers / fabric filters (DS/FF)

Cited by 8 publications

References 3 publications

Entrained-Phase Adsorption of PCDD/F from Incinerator Flue Gases

Entrained-Phase Adsorption of PCDD/F from Incinerator Flue Gases

Adsorption of dioxins and furans from flue gases in an entrained flow or fixed/moving bed reactor

Evaluation of Polychlorinated Dibenzo-p-dioxin/Dibenzofuran (PCDD/F) Emission in Municipal Solid Waste Incinerators

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