Letteratura scientifica selezionata sul tema "Régénération de catalyseurs"
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Articoli di riviste sul tema "Régénération de catalyseurs":
Bouallag-Azoui, Ouafida, e Ewa Berezowska-Azzag. "L’équipement emblématique, un levier de la régénération urbaine ?" Cahiers de géographie du Québec 60, n. 169 (16 gennaio 2017): 57–81. http://dx.doi.org/10.7202/1038665ar.
GUISNET, Michel, e Ludovic PINARD. "Catalyse hétérogène : désactivation et régénération des catalyseurs". Opérations unitaires. Génie de la réaction chimique, marzo 2014. http://dx.doi.org/10.51257/a-v1-j1265.
Alves, Julio, Mariana Oliveira, Robin Chazdon, Miguel Calmon, Andreia Pinto, Eduardo Darvin e Bruna Pereira. "Le rôle de la régénération naturelle assistée dans l’accélération de la restauration des paysages forestiers: Expériences pratiques du terrain". World Resources Institute, 2022. http://dx.doi.org/10.46830/wripn.21.00081fr.
Tesi sul tema "Régénération de catalyseurs":
Gamez, Stéphane. "Désactivation et régénération des catalyseurs d'hydrodésulfuration". Lyon 1, 2000. http://www.theses.fr/2000LYO10206.
Sénécal, Pierre. "Caractérisation du cycle régénération – réjuvénation de catalyseurs d’hydrotraitement additivés". Thesis, Lille 1, 2013. http://www.theses.fr/2013LIL10098.
The regeneration (mild calcination) of used hydrodesulfurization catalysts is an economically and ecologically interesting procedure as it permits the re-use of these catalysts in the industrial plant instead of recycling them. But these regenerated catalysts are usually less active than the original materials. To overcome this problem, these regenerated catalysts can be treated with various organic agents, this process being called “rejuvenation”. To improve this rejuvenation procedure it is necessary to understand firstly, why the regenerated catalysts are less active and secondly, what is the role of the organic agents. With these aims, this work was performed on CoMoP/Al2O3 hydrodesulfurization catalysts. The regeneration step is responsible for the formation of weakly sulfidable species such as CoMoO4 and CoAl2O4 which can explain the decrease in performance of these catalysts. The study of model catalysts and catalysts which were regenerated in the laboratory or industrially show that some organic compounds permit the redispersion of all or part of these undesirable species depending on the solvent used for their impregnation. This redispersion seems to be due to metal complexation with the organic agents. The role of these agents on the Co and Mo sulfidation is also discussed. Due to the metals redispersion and the effect on the Co and Mo sulfidation, the rejuvenation step leads to an increase in the number of active sites and thus to an enhancement of the straight run gas oil HDS catalytic performance (which has been evaluated using a pilot unit)
Pedraza, Parra Camila Andrea. "Régénération et réactivation de catalyseurs d'hydrotraitement : vers la compréhension des paramètres de réjuvenation". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1325.
Regeneration and reactivation of used industrial CoMo/Al2O3 hydrodesulfurization (HDS) catalysts allows reusing them. Since these catalysts are considered toxic and pollutant, regeneration/reactivation is an interesting procedure from an economical and ecological point of view. The regeneration allows removing carbon deposits but, by itself, does not restore completely the activity of new generations of HDS catalysts. Consequently, a second stage named rejuvenation, involving addition of organic compounds has been implemented. The study of the impact of additives is of great interest but many observations remain unexplained. Furthermore, some patents have described a pre-activation procedure that allows activating catalysts ex situ in order to avoid contact with sulfur compounds and a safe handling and loading of the catalysts in HDS units. In addition, it is common knowledge that sulfidation is a critical stage that impacts strongly the catalytic performance. In this sense, this study aims to study the effect of different rejuvenation, pre-activation and subsequent sulfidation conditions on final characteristics of catalysts. In this work three rejuvenated and pre-activated catalysts were studied after different sulfidation protocols. Catalysts were tested and compared in thiophene and SRGO HDS. Additionally, the influence of the organic compounds added during rejuvenation was studied by different techniques (XPS, CO/IR, TEM…). Results allowed determining differences in catalytic activity and establishing a correlation between thiophene HDS activity and CoMoS concentration. No morphological divergences were detected in the systems, instead, differences in catalytic performances are attributed to an unequal promotion degree
Bui, Ngoc-Quynh. "Nouvel additif pour l'activation de catalyseurs d'hydrotraitement régénérés". Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10184.
The objective of this study is to improve the activation of regenerated CoMo/Al2O3 hydrotreating catalysts through the use of a novel organic additive, maleic acid. The regeneration process allows to re-use hydrotreating catalysts that have been deactivated leading to the removal of carbon impurities and to the redispersion of the active at the catalyst surface. However, using this process, the regenerated catalyst cannot recover completely the activity of a fresh catalyst. The use of organic additives during the preparation of regenerated catalysts can improve the final catalytic activity. In this work, the influence of maleic acid has been studied at each step of the activation procedure of a regenerated hydrotreating catalyst. At the oxide state, maleic acid does not influence the formation of cobalt aluminate while after maturation at 30°C, this additive can consume the CoMoO4 phase known to be detrimental to the activity. This disappearance of the CoMoO4 phase is accompanied by the formation of cobalt maleate. Complementary studies based on the extraction of oxide species through the interaction of the regenerated catalyst with maleic acid in aqueous solution also evidence the redispersion of molybdenum as AlMo6 Anderson salt species. This redispersion allows to rapidly sulphide molybdenum as soon as 150°C while cobalt is progressively sulphided before the maleate decomposition. The complete decomposition of cobalt maleate at 350°C makes cobalt available to interact efficiently with the already formed molybdenum sulphide leading to a high proportion of promoted phase
Daniel, Stéphane. "Elaboration d'une méthodologie de simulation de four tournant : application à la pyrolyse de déchets et à la régénération de catalyseurs cokes". Vandoeuvre-les-Nancy, INPL, 2003. http://www.theses.fr/2003INPL005N.
The rotary kiln is one of the most widely used industrial reactors to treat solids. In the present work, this kind of unit is described using both experimental and theotetical investigations. The movement of the bed (axial and transverse), the heat transfers within the kiln and the reactions kinetics have been studied to develop mathematical models. Two different processes (catalysts regeneration and solid wastes) have been chosen to illustrate the methodology application to various cases (reaction and kiln geometry). The application to the catalysts regeneration has led to the elaboration of a simulation tool, giving information on the kiln behavior and identify eventual problems. The application to the pyrolysis kiln has given a numerical tool, which is usable to design industrial deviees. In the both cases, the results obtained by simulation are in good agreement with the experimental data
Fadili, Kamal. "Régénération des catalyseurs modèles de vaporéformage à base de nickel désactivés par dépôt de carbone filamentaire". Poitiers, 1996. http://www.theses.fr/1996POIT2323.
Limousy, Lionel. "Etude de l'empoisonnement par le soufre d'un catalyseur d'amorçage destiné à protéger un piège à NOx : recherche d'une stratégie de régénération". Mulhouse, 2000. http://www.theses.fr/2000MULH0611.
Medina, Molano Natalia Stefania. "Contribution of radioactivity to catalytic performance in heterogeneous media". Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILR025.
This thesis aimed to identify applications of noble metals recovered from spent nuclear fuels such as 107Pd. To study the effect of the radiation three different applications were selected: heterogeneous catalysis, with the hydrogenation of cinnamaldehyde (CNA) as model reaction; photocatalysis, with the decolourisation of methyl orange (MO) as model reaction; and the regeneration of catalysts, deactivated with the synthesis of hydroxymethyl furfural. Protocols were developed for the synthesis of the catalysts and the performance testing in restricted nuclear environment, namely in glove box and for the implementation of the reactions in glove box and extractor column as appropriate.Regarding the results it was found that β-radiation did not show any effect on the hydrogenation of CNA independent of the applied reaction conditions. On the other hand, the decolourisation of MO was successfully activated by the β-radiation of the catalyst. A decrease in absorbance (at the isosbestic point) was observed and was correlated to the amount of the catalyst employed, evidencing the effect of the irradiation doses. Finally, the regeneration of the Pd-based catalyst showed promising results after γ-irradiation, notably with a partial recovery of the initial catalytic performance after -irradiation. Meanwhile, the Ru-based catalyst, although generally not performing well, showed increased activity compared to the fresh catalyst upon -irradiation
Klaimy, Sophie. "Pyrolyse thermique et catalytique des polymères utilisés dans les emballages". Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1R056.
Over the past ten years, the production and consumption of plastics have grown significantly around the world due to their uses in a wide range of applications including packaging, agriculture, automotive or construction. In 2017, 342 million tons of plastics were produced worldwide among them around 65 million tons in Europe. The valorization of plastic waste by mechanical recycling or incineration are widely used but do not constitute a long-term solution. Thermal as well as catalytic pyrolysis appears as an attractive alternative. The research carried out in this PhD work focused on pyrolysis of plastics used in packaging such as polyethylene (PE), polypropylene (PP), polystyrene (PS) and polyethylene terephthalate (PET). The thermal decomposition of virgin polymers and of a defined model mixture representative of plastic waste were studied by thermogravimetric analysis and flash pyrolysis. The quantity of each phases (gas, liquid, solid) were determined and the composition of the liquid phase analyzed. It was demonstrated that, within the model mixture, interaction between the polymers occurs leading to accelerate the decomposition process and to favor the formation of aromatic compounds. The use of zeolite (ZSM-5) as a catalyst for the pyrolysis of polyethylene, the most commonly used plastic in packaging, lead to a narrower distribution of pyrolysis products. The amount of catalyst was optimized and the effect of its acidity was studied. The most acidic ZSM-5 promotes the formation of aromatics and specifically products between C6 and C12 are obtained. The deactivation and regeneration of ZSM-5 respectively before and after pyrolysis was also investigated. The effectiveness of catalyst regeneration after several cycles of use was demonstrated. Finally, several catalysts with defined structure and acidities were synthesized. It was thus possible to conclude that both parameters play an important role in the composition and selectivity of the pyrolysis process
Kumar, Kavita. "Catalyseurs sans métaux nobles pour pile à combustible régénérative". Thesis, Poitiers, 2017. http://www.theses.fr/2017POIT2284/document.
Hydrogen, as an environmentally friendly future energy vector, is a non-toxic and convenient molecule for regenerative fuel cell, which connects two different technologies: an electrolyzer for H2 production, and a fuel cell for its direct conversion to electric energy. This kind of system possesses many advantages, such as lightness, compactness and more autonomy. However, improvement of activity and durability of electrode materials free from noble metals in their composition is needed. Thereby, bifunctional catalysts composed of transition metals deposited onto graphene-based materials were synthesized. The interaction between the metal atom of the oxide and the graphene doped heteroatom in the Co3O4/NRGO catalyst was investigated physicochemically. With a low cobalt loading, the interaction between cobalt and nitrogen was characterized by cyclic voltammetry, which revealed that it was responsible for decreasing the oxide nanoparticle size, as well as increasing the material activity towards the oxygen reduction reaction (ORR). The substitution of Co by Ni in the spinel structure (NiCo2O4/RGO) obtained by solvothermal synthesis, allowed the enhancement of the electrocatalytic performances towards the ORR and OER. Moreover, this catalyst as well as another material prepared in collaborative program with a lab from Technical University of Berlin were used as cathode in preliminary studies undertaken on solid alkaline fuel cell (SAFC)