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Communication Dans Un Congrès Année : 2017

Novel insights on H2S and COS removal for gas purification applications

Résumé

H2S and COS are well-known gaseous pollutants encountered in many applications. Synthetic fuels produced from thermochemical routes (Fisher-Tropsch based XTL processes) or IGCC technologies for cleaner power production are among the applications for which the removal of H2S and COS from intermediate synthesis gas products is critical. Indeed, H2S and COS are known severe poisons for FT catalysts, corrosive for industrial equipments, but also acute environmental pollutants and display high toxicity. Natural gas and biogas applications also face similar issues which require H2S and/or COS removal. Some fundamental studies conducted at IFPEN have dealt with sulfur removal issues from gases. A review of some recent studies will be presented. A part of our work focused on kinetics modeling and solid-state transformations involved in metal oxides sulfidation and oxidizing regeneration reactions, in the scope of H2S removal processes over metal oxides. We questioned some generally admitted assumptions regarding ZnO sulfidation mechanism and kinetics modeling. With the support of materials characterizations such as 3D-TEM, we evidenced that an outward growth process of the ZnS phase upon ZnO crystals was more likely to occur, compared to inward development mechanisms generally assumed. Updated mechanism and kinetics modeling were also proposed. Regeneration properties of various metal oxides were also studied, showing that mixed metal oxides are for this purpose more adapted, and that lower regeneration temperature can be reached. We also interested in the understanding and the modeling of dedicated COS adsorption and catalytic based removal processes. We focused on the study of the interactions taking place in COS adsorption on doped or undoped oxides (Al2O3, TiO2 and ZrO2). Sorbents stability over adsorption-regeneration cycles was also investigated. Besides, we explored the modeling of catalytic processes used for COS and HCN elimination in the field of synthesis gas purification applications. A reaction model was developed considering hydrodynamic, mass transfer limitations, and Langmuir-Hinshelwood reaction mechanisms for both COS and HCN hydrolysis reactions. LH rate laws accounted for the detrimental effect of gaseous reactants and products upon COS and HCN conversion kinetic rates. Our work included in a multi-technique and multi-scale approach brings novel and rational insights on reactions involved at the heart of H2S and COS sorption and catalytic removal processes. This finally leads to rational pathways to a better design of industrial sorbents, catalysts and processes.
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Dates et versions

hal-01895542 , version 1 (15-10-2018)

Identifiants

  • HAL Id : hal-01895542 , version 1

Citer

David Chiche, Laure Neveux, Vincent Girard, Taha Hlayhel, Karin Barthelet, et al.. Novel insights on H2S and COS removal for gas purification applications. 10th World Congress of Chemical Engineering- WCCE10, Anque; Enginyers Industrials de catalunya; SEQUI A; A IQS, Oct 2017, Barcelone, Spain. pp.363. ⟨hal-01895542⟩
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