Alkali poisoning of Fe-Cu-ZSM-5 catalyst for the selective catalytic reduction of NO with NH3

[EN] Fe (2 wt%)-Cu (1.5 wt%)-ZSM-5 SCR catalyst contacted 1.5 wt% of Na and 1.8 wt% of K in order to simulate poisoning by species more specifically contained in exhaust gases from exhaust gases of diesel engines and power plants. Poisoning agents do not cause loss of surface area nor pore occlusion. XRD and SEM results showed that alkali metals introduction did not deteriorate the crystallinity and morphology of zeolite crystals. However, a significant loss of surface acidity was observed upon alkali-poisoned catalysts causing a dramatic deactivation of the NH3-SCR of NO reaction. Na-doped catalyst showed higher low-temperature SCR activity, while potassium has a stronger deactivation effect on Fe-Cu-ZSM-5 than sodium beyond 400 degrees C.Jouini, H.; Mejri, I.; Martinez-Ortigosa, J.; Cerrillo, JL.; Petitto, C.; Mhamdi, M.; Blasco Lanzuela, T.... (2022). Alkali poisoning of Fe-Cu-ZSM-5 catalyst for the selective catalytic reduction of NO with NH3. Research on Chemical Intermediates. 48(8):3415-3428. https://doi.org/10.1007/s11164-022-04768-93415342848

Analyse de l'écoulement instationnaire cavitant dans les inducteurs

Faced with the problem of design in the pump industry, the main difficulty of manufacturers is to have fast, reliable and accurate methods. So far, inducers have been designed principally on an empirical basis, and we depend on such empirical data for the basic engineering design. However, CFD is becoming a dependable tool to predict steady and even unsteady flow with cavitation. With these CFD new and powerful tools, it is expected that we will be able to obtain explanations for the inducers cavitation instabilities and offer new methodologies for the design of stable and reliable inducers and inducer main-stage performance. This research work involving both theory and experiments, deals with this topic. We have developed a complete procedure for design, performance analysis and optimization of inducers geometry. First of all, three-dimensional calculations are carried out for inducers in steady cavitating and non cavitating conditions. Based on both numerical results and experimental test, a second stage of analysis is achieved into unsteady flow conditions. The observation of partial cavities under various conditions leads to the conclusion that the characteristic size of the region in which unsteady effects are significant is variable. In deed, it depends on the inducers design parameters. In some cases, cavitating flow unsteadiness is confined in a relatively small region, so that the cavity can be considered as stable, at least from a large scale viewpoint. Cavitation is handled using special experimental and numerical methodologies. The three-dimensional flow study is performed by CFD tools from ANSYS-Canada group, with the collaboration of the New Brunswick University. This study was illustrated on one of our inducers and it provides the means to complete and validate the cavitating flow simulation procedure of the CFX5.7 code.Dans les turbomachines et plus particulièrement dans les inducteurs, la cavitation reste un sujet de préoccupation majeure. L'évolution rapide de l'industrie dans les turbomachines combinée aux récents progrès réalisés en CFD, permettent une investigation, une analyse et un diagnostic numériques de ces machines par une meilleure connaissance des caractéristiques des écoulements dont elles sont le siège. Dans le cadre de ce travail, nous avons étudié une gamme d'inducteurs qui se différentient par certains critères géométriques en écoulements cavitants et subcavitants. Les interactions entre les divers critères géométriques étudiés, jouent sans le moindre doute un rôle important et nécessitent la prise en compte d'un couplage entre ces paramètres dans les diverses conditions de fonctionnement prévisibles (débit, NPSH, etc.). L' =un des objectifs est d'aboutir, à terme, à une amélioration du processus de conception des inducteurs. La mise en oeuvre de calculs tridimensionnels cavitants, a permis d'analyser les caractéristiques de l'écoulement dans les différentes configurations d'inducteurs pour des régimes de fonctionnement stables et instables, et de détecter les paramètres les plus importants affectant leur bon fonctionnement. Une méthodologie de modélisation des caractéristiques a pu ainsi être mise en oeuvre et appliquée sur différentes géométries avec succès. Un autre objectif poursuivi est de mieux cerner à la fois expérimentalement et numériquement le phénomène de cavitation particulièrement dans ce type de machines en écoulement stationnaire et instationnaire. Ceci a permis d'établir des méthodes précises pour la prédiction de son apparition et du développement de ses différents aspects afin de repousser les limites techniques qu'elle engendre. De manière plus générale, notre collaboration avec ANSYS-Canada et l'Université du New Brunswick au cours de ce travail, a donné lieu à la validation du modèle cavitant du code CFX5.7 sur l'un des inducteurs présentés dans ce rapport

Analyse de l'écoulement instationnaire cavitant dans les inducteurs

Dans les turbomachines et plus particulièrement dans les inducteurs, la cavitation reste un sujet de préoccupation majeure. L'évolution rapide de l'industrie dans les turbomachines combinée aux récents progrès réalisés en CFD, permettent une investigation, une analyse et un diagnostic numériques de ces machines par une meilleure connaissance des caractéristiques des écoulements dont elles sont le siège. Dans le cadre de ce travail, nous avons étudié une gamme d'inducteurs qui se différentient par certains critères géométriques en écoulements cavitants et subcavitants. Les interactions entre les divers critères géométriques étudiés, jouent sans le moindre doute un rôle important et nécessitent la prise en compte d'un couplage entre ces paramètres dans les diverses conditions de fonctionnement prévisibles (débit, NPSH, etc.). L' =un des objectifs est d'aboutir, à terme, à une amélioration du processus de conception des inducteurs. La mise en oeuvre de calculs tridimensionnels cavitants, a permis d'analyser les caractéristiques de l'écoulement dans les différentes configurations d'inducteurs pour des régimes de fonctionnement stables et instables, et de détecter les paramètres les plus importants affectant leur bon fonctionnement. Une méthodologie de modélisation des caractéristiques a pu ainsi être mise en oeuvre et appliquée sur différentes géométries avec succès. Un autre objectif poursuivi est de mieux cerner à la fois expérimentalement et numériquement le phénomène de cavitation particulièrement dans ce type de machines en écoulement stationnaire et instationnaire. Ceci a permis d'établir des méthodes précises pour la prédiction de son apparition et du développement de ses différents aspects afin de repousser les limites techniques qu'elle engendre. De manière plus générale, notre collaboration avec ANSYS-Canada et l'Université du New Brunswick au cours de ce travail, a donné lieu à la validation du modèle cavitant du code CFX5.7 sur l'un des inducteurs présentés dans ce rapport.Faced with the problem of design in the pump industry, the main difficulty of manufacturers is to have fast, reliable and accurate methods. So far, inducers have been designed principally on an empirical basis, and we depend on such empirical data for the basic engineering design. However, CFD is becoming a dependable tool to predict steady and even unsteady flow with cavitation. With these CFD new and powerful tools, it is expected that we will be able to obtain explanations for the inducers cavitation instabilities and offer new methodologies for the design of stable and reliable inducers and inducer main-stage performance. This research work involving both theory and experiments, deals with this topic. We have developed a complete procedure for design, performance analysis and optimization of inducers geometry. First of all, three-dimensional calculations are carried out for inducers in steady cavitating and non cavitating conditions. Based on both numerical results and experimental test, a second stage of analysis is achieved into unsteady flow conditions. The observation of partial cavities under various conditions leads to the conclusion that the characteristic size of the region in which unsteady effects are significant is variable. In deed, it depends on the inducers design parameters. In some cases, cavitating flow unsteadiness is confined in a relatively small region, so that the cavity can be considered as stable, at least from a large scale viewpoint. Cavitation is handled using special experimental and numerical methodologies. The three-dimensional flow study is performed by CFD tools from ANSYS-Canada group, with the collaboration of the New Brunswick University. This study was illustrated on one of our inducers and it provides the means to complete and validate the cavitating flow simulation procedure of the CFX5.7 code.PARIS-Arts et Métiers (751132303) / SudocSudocFranceF

On the performance of Fe-Cu-ZSM-5 catalyst for the selective catalytic reduction of NO with NH3: the influence of preparation method

[EN] The selective catalytic reduction of NO with ammonia (NH3-SCR) in the presence of H2O was studied over a series of Fe-Cu-ZSM-5 catalysts prepared by solid-state ion exchange (SSIE), aqueous ion exchange and impregnation methods. The prepared samples were characterized by various techniques (ICP-AES, N-2 physisorption at 77K, XRD, STEM-EDX, XPS, H-2-TPR and DRS UV-vis) to investigate the effect of the preparation method on the activity, texture, structure and metal speciation of the studied catalysts. It was found that the aqueous ion exchange method induced a significant metal loss during the preparation procedure but without any activity deterioration of the catalyst which encloses highly dispersed metal species. The catalysts prepared by SSIE and impregnation showed the highest metal contents and a large number of oxide aggregates leading to an activity decline at high reaction temperatures due to the ammonia oxidation phenomenon.Financial support by the MINECO of Spain through the Severo Ochoa (SEV-2016-0683) and CTQ2015-68951C3-1-R projects is gratefully acknowledged. The authors thank the Electron Microscopy Service of the Universitat Politecnica de Valencia for STEM experiments. J. Martinez-Ortigosa (SEV-2012-0267-02) is grateful to Severo Ochoa Program for a predoctoral fellowship.Jouini, H.; Martinez-Ortigosa, J.; Mejri, I.; Mhamdi, M.; Blasco Lanzuela, T.; Delahay, G. (2019). On the performance of Fe-Cu-ZSM-5 catalyst for the selective catalytic reduction of NO with NH3: the influence of preparation method. Research on Chemical Intermediates. 45(3):1057-1072. https://doi.org/10.1007/s11164-018-3658-81057107245

Ce-promoted Fe–Cu–ZSM-5 catalyst: SCR-NO activity and hydrothermal stability

Fe–Cu–ZSM-5 and Ce–Fe–Cu–ZSM-5 solids prepared using solid-state ion exchange method (SSIE) were tested in the NH–SCR of NO reaction and were characterized using N physisorption at 77 K, MAS Al magnetic resonance, X-ray diffraction, scanning electron microscopy, EPR spectroscopy and transmission electron microscopy coupled to energy-dispersive X-ray spectroscopy in order to follow the effect of Ce addition on the textural and structural properties of Fe–Cu–MFI system as well as the detection of the changes in local environment and state of iron and copper species, and the degradation of the zeolite texture and structure after a severe aging treatment at 850 °C for 5 h. Fresh Ce-promoted sample showed better NO conversion up to 450 °C than unpromoted Fe–Cu–ZSM-5 catalyst. An activity loss was observed on aged catalysts, but remaining less pronounced for the catalyst containing Ce. The changes in catalyst structure and texture did not occur during aging, while a probable migration of metal active species and change in their coordination has occurred.Financial support by the MINECO of Spain through the Severo Ochoa (SEV-2016-0683) and RTI2018-101784-B-I00 projects is gratefully acknowledgedPeer reviewe

Understanding the Catalytic Deactivation upon Hydrothermal Aging at 850 °C of WO3/Fe-Cu-ZSM-5 Catalyst for Selective Catalytic Reduction of NO by NH3

A WO3/Fe-Cu-ZSM-5 catalyst was prepared using the solid state ion exchange method (SSIE) and its performance for the Selective Catalytic Reduction of NO with NH3 (NH3-SCR of NO) was investigated. The study shows that the tungsten addition can slightly improve the high temperature catalytic activity of Fe-Cu-ZSM-5. The influence of hydrothermal aging at 850 °C for 5 h on the structural and textural properties of WO3/Fe-Cu-ZSM-5 was also studied in this paper. The XRD and FE-SEM measurements did not indicate a breakdown of the zeolite structure upon steam treatment for both aged catalysts. The aged W-base catalyst demonstrates a lower deactivation and better catalytic activity for NO reduction than the bimetallic catalyst after hydrothermal aging despite the lower acidic properties as shown by FTIR-Pyr spectroscopy owing to the presence of tungsten oxide crystallites. The “severe” stage of aging occurring in the absence of W led to the formation of copper oxide agglomerates detected using STEM and H2-TPR techniques being responsible for the deterioration of SCR activity of the aged Fe-Cu-ZSM-5

Understanding the Catalytic Deactivation upon Hydrothermal Aging at 850 °C of WO3/Fe-Cu-ZSM-5 Catalyst for Selective Catalytic Reduction of NO by NH3

A WO/Fe-Cu-ZSM-5 catalyst was prepared using the solid state ion exchange method (SSIE) and its performance for the Selective Catalytic Reduction of NO with NH (NH-SCR of NO) was investigated. The study shows that the tungsten addition can slightly improve the high temperature catalytic activity of Fe-Cu-ZSM-5. The influence of hydrothermal aging at 850 °C for 5 h on the structural and textural properties of WO/Fe-Cu-ZSM-5 was also studied in this paper. The XRD and FE-SEM measurements did not indicate a breakdown of the zeolite structure upon steam treatment for both aged catalysts. The aged W-base catalyst demonstrates a lower deactivation and better catalytic activity for NO reduction than the bimetallic catalyst after hydrothermal aging despite the lower acidic properties as shown by FTIR-Pyr spectroscopy owing to the presence of tungsten oxide crystallites. The “severe” stage of aging occurring in the absence of W led to the formation of copper oxide agglomerates detected using STEM and H-TPR techniques being responsible for the deterioration of SCR activity of the aged Fe-Cu-ZSM-5.The authors thank the Microscopy Service of the Universitat Politècnica de València for its assistance in sample characterization. Teresa Blasco acknowledge the financial support of the Generalitat Valenciana, Conselleria d’Innovació, Universitats Ciència y Societat Digital (Prometeo/2021/077) and the Spanish Ministry of Science and Innovation (SEV-2016-0683-19-2). Alessandra de Marcos-Galán thanks the predoctoral grant PRE2019-090465

Alkali poisoning of Fe-Cu-ZSM-5 catalyst for the selective catalytic reduction of NO with NH3

Fe (2 wt%)-Cu (1.5 wt%)-ZSM-5 SCR catalyst contacted 1.5 wt% of Na and 1.8 wt% of K in order to simulate poisoning by species more specifically contained in exhaust gases from exhaust gases of diesel engines and power plants. Poisoning agents do not cause loss of surface area nor pore occlusion. XRD and SEM results showed that alkali metals introduction did not deteriorate the crystallinity and morphology of zeolite crystals. However, a significant loss of surface acidity was observed upon alkali-poisoned catalysts causing a dramatic deactivation of the NH-SCR of NO reaction. Na-doped catalyst showed higher low-temperature SCR activity, while potassium has a stronger deactivation effect on Fe-Cu-ZSM-5 than sodium beyond 400 °C

Characterization and NH 3 -SCR reactivity of Cu-Fe-ZSM-5 catalysts prepared by solid state ion exchange: The metal exchange order effect

International audienc

Selective catalytic reduction of nitric oxide with ammonia over Fe-Cu modified highly silicated zeolites

[EN] In the present study, the solid-state ion exchange method (SSIE) was applied to introduce iron and copper into highly silicate zeolites: beta (BEA, Si/Al¿=¿12.5), ferrierite (FER, Si/Al¿=¿10) and mordenite (MOR, Si/Al¿=¿10). The activity of the prepared samples in the selective catalytic reduction of NO with ammonia (NH3-SCR) was measured. The highest performance was recorded for Cu-Fe-BEA followed by Cu-Fe-MOR while Cu-Fe-FER showed a low catalytic activity over the entire reaction temperature range. It is shown in this study that the zeolite framework is one of the parameters controlling the amount, environment and distribution of metal species formed during the ion exchange process in Cu-Fe-zeolite catalysts.Financial support by the MINECO of Spain through the Severo Ochoa (SEV-2016-0683) and CTQ2015-68951C3-1-R projects is gratefully acknowledged. The authors thank the Electron Microscopy Service of the Universitat Politecnica de Valencia, Spain for STEM experiments. J. Martinez-Ortigosa (SEV-2012-0267-02) is grateful to Severo Ochoa Program for a predoctoral fellowship.Jouini, H.; Mejri, I.; Martinez-Ortigosa, J.; Cerrillo, JL.; Mhamdi, M.; Palomares Gimeno, AE.; Delahay, G.... (2018). Selective catalytic reduction of nitric oxide with ammonia over Fe-Cu modified highly silicated zeolites. Solid State Sciences. 84:75-85. https://doi.org/10.1016/j.solidstatesciences.2018.08.008S75858