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Modélisation mathématique de la formation des NOx et de la volatilisation des métaux lourds lors de l'incinération sur grille d'ordures ménagères

Abstract : As a tool for controlling the Municipal Solid Waste (MSW) incineration process and its possible pollutant emissions, a mathematical model of the MSW bed burning on travelling grate of an incinerator was developed. The model describes most of the physico-chemical and thermal phenomena taking place in incineration like the drying and pyrolysis of the feed, combustion and gasification of char, oxidation of pyrolysis gases, heat transfer, bed shrinking, feed stirring, etc. Also described in the model are the mechanisms of Heavy Metals (HM) volatilization and NOx formation. Kinetics of HM release was modelled using the approach of additive reaction times accounting for the various transport mechanisms involved: external transfer, intra-particle diffusion and actual volatilization. In the case simulated, i.e. of Cd, almost total volatilization is predicted, which is confirmed by literature findings. The NOx sub-model takes into account most of the common mechanisms of formation like thermal, prompt, fuel, N2O intermediate and also NOx reduction by homogeneous reburning and heterogeneous reduction by char. Calculations show that NOx formation is predominated by the fuel mechanism and destruction by the heterogeneous reduction. Finally, the bed model was applied to study the influence of various operating parameters like flow rate, temperature and distribution of air under grates, waste particle size, feed stirring and the stirring scheme. The results are presented and discussed in detail and the influence of operating conditions on process efficiency and on emissions of Cd and NOx is analyzed.
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https://tel.archives-ouvertes.fr/tel-01753018
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Submitted on : Thursday, June 5, 2008 - 3:12:59 PM
Last modification on : Friday, November 13, 2020 - 8:52:02 AM
Long-term archiving on: : Friday, May 28, 2010 - 6:58:41 PM

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  • HAL Id : tel-01753018, version 2

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A. Asthana. Modélisation mathématique de la formation des NOx et de la volatilisation des métaux lourds lors de l'incinération sur grille d'ordures ménagères. Génie des procédés. Institut National Polytechnique de Lorraine - INPL, 2008. Français. ⟨NNT : 2008INPL018N⟩. ⟨tel-01753018v2⟩

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