Papers by Magali Boutonnet
Grace
Elsevier eBooks, 2005
This chapter presents the development of Pd-zeolite composite membranes for hydrogen production b... more This chapter presents the development of Pd-zeolite composite membranes for hydrogen production by membrane reactor. Pd-zeolite composite membranes are prepared over the external surface of macroporous α-alumna tubular supports by secondary growth of zeolite layers followed by Pd modification. Pd nanoparticles filtration and/or impregnation + in situ reduction of an organic Pd precursor are explored as deposition techniques devoted to enhance the H 2 separation performance of the non-defect free A-type zeolite membranes. The Pd deposition aims toward the partial blockage of the non-selective intercrystalline pathways, which may account for a significant fraction of the total permeation flux. The Pd-zeolite composite substrates are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and EDX. The study of the permeation properties of these substrates for single (N 2 ) and binary mixtures (H 2 –CO 2 ) before and after Pd modification reveals some improvements in terms of H 2 separation performance. The impregnation + in situ reduction of palladium acetylacetonate solution (Pd(acac) 2 ) carried out over KA zeolite membranes previously seeded with Pd nanoparticles appears as the most adequate among the tested methods. Separation factors for H 2 -CO 2 binary mixtures up to 145 have been achieved, although further optimization is required to improve the H 2 permeation fluxes (around 10 −8 mol H 2 /m 2 s Pa).
Catalysis and plasma technology - Preface
Catalysis Today, 2002
Microemulsion: An alternative route to preparing supported catalysts
The Royal Society of Chemistry eBooks, Jun 4, 2004
ABSTRACT For Abstract see ChemInform Abstract in Full Text.
Catalysis
Catalysis, 2007
There is an increasing challenge for chemical industry and research institutions to find cost-eff... more There is an increasing challenge for chemical industry and research institutions to find cost-efficient and environmentally sound methods of converting natural resources into fuels chemicals and energy. Catalysts are essential to these processes and the Catalysis Specialist Periodical Report series serves to highlight major developments in this area. This series provides systematic and detailed reviews of topics of interest to scientists and engineers in the catalysis field. The coverage includes all major areas of heterogeneous and homogeneous catalysis and also specific applications of catalysis such as NOx control kinetics and experimental techniques such as microcalorimetry. Each chapter is compiled by recognised experts within their specialist fields and provides a summary of the current literature. This series will be of interest to all those in academia and industry who need an up-to-date critical analysis and summary of catalysis research and applications. Catalysis will be ...
Liquid phase hydrogenation of crotonaldehyde over Au/CeO2 catalysts
Applied Catalysis A: General, 2009
Three Au/CeO2 catalysts, with different specific surface area (80, 150 and 240m2/g) were tested f... more Three Au/CeO2 catalysts, with different specific surface area (80, 150 and 240m2/g) were tested for the hydrogenation of crotonaldehyde in liquid phase. Reactions were carried out with molecular hydrogen as the reductant, in a batch reactor using isopropanol as the solvent, at 80°C and 1MPa. The high surface area catalyst (Au/CeO2, 240m2/g) showed a selectivity towards crotyl alcohol of 29%.
Effect of Magnetic Iron Oxide Nanoparticles for Surface Water Treatment: Trace Minerals and Microbes
Sintering resistant catalyst material and a method for the preparation thereof
High-surface-area lanthanum hexaaluminates by carbon templating
Catalytic combustion is a promising technology for heat and power applications, especially gas tu... more Catalytic combustion is a promising technology for heat and power applications, especially gas turbines. By using catalytic combustion ultra low emissions of nitrogen oxides (NOX), carbon monoxide (CO) and unburned hydrocarbons (UHC) can be reached simultaneously, which is very difficult with conventional combustion technologies. Besides achieving low emission levels, catalytic combustion can stabilize the combustion and thereby be used to obtain stable combustion with low heating-value gases. This thesis is focused on the high-temperature part of the catalytic combustor. The level of performance demanded on this part has proven hard to achieve. In order to make the catalytic combustor an alternative to the conventional flame combustor, more stable catalysts with higher activity have to be developed. The objective of this work was to develop catalysts with higher activity and stability, suitable for the high-temperature part of a catalytic combustor fueled by natural gas. Two template-based preparation methods were developed for this purpose. One method was based on soft templates (microemulsion) and the other on hard templates (carbon). Supports known for their stability, magnesia and hexaaluminate, were prepared using the developed methods. Catalytically active materials, perovskite (LaMnO3) and ceria (CeO2), were added to the supports in order to obtain catalysts with high activities and stabilities. The supports were impregnated with active materials by using a conventional technique as well as by using the microemulsion technique. It was shown that the microemulsion method can be used to prepare catalysts with higher activity compared to the conventional methods. Furthermore, by using a microemulsion to apply active materials onto the support a significantly higher activity was obtained than when using the conventional impregnation technique. Since the catalysts will operate in the catalytic combustor for extended periods of time under harsh conditions, an aging study was performed on selected catalysts prepared by the microemulsion technique. The stability of the catalysts was assessed by measuring the activity before and after aging at 1000 C in humid air for 100 h. One of the most stable catalysts reported in the literature, LMHA (manganese-substituted lanthanum hexaaluminate), was included in the study for comparative purposes. The results showed that LMHA deactivated much more strongly compared to several of the catalysts consisting of ceria supported on lanthanum hexaaluminate prepared by the developed microemulsion method. Carbon templating was shown be a very good technique for the preparation of high-surface-area hexaaluminates with excellent sintering resistance. It was found that the pore size distribution of the carbon used as template was a crucial parameter in the preparation of hexaaluminates. When a carbon with small pores was used as template, the formation of the hexaaluminate crystals was strongly inhibited. This resulted in a material with poor sintering resistance. On the other hand, if a carbon with larger pores was used as template, it was possible to prepare materials with hexaaluminate as the major phase. These materials were, after accelerated aging at 1400 C in humid air, shown to retain surface areas twice as high as reported for conventionally prepared materials.
Reactor for decomposition of ammonium dinitramide-based liquid monopropellants and process for the decomposition
Reactor for decomposition of ammonium dinitramide-baed liquid monopropellants and process for the decomposition
Synthesis of barium hexaaluminate by co-precipitation in microemulsion
Materials Chemistry and Physics, 2008
Catalytic combustion is a promising technology for heat and power applications, especially gas tu... more Catalytic combustion is a promising technology for heat and power applications, especially gas turbines. By using catalytic combustion ultra low emissions of nitrogen oxides (NOX), carbon monoxide (CO) and unburned hydrocarbons (UHC) can be reached simultaneously, which is very difficult with conventional combustion technologies. Besides achieving low emission levels, catalytic combustion can stabilize the combustion and thereby be used to obtain stable combustion with low heating-value gases. This thesis is focused on the high-temperature part of the catalytic combustor. The level of performance demanded on this part has proven hard to achieve. In order to make the catalytic combustor an alternative to the conventional flame combustor, more stable catalysts with higher activity have to be developed. The objective of this work was to develop catalysts with higher activity and stability, suitable for the high-temperature part of a catalytic combustor fueled by natural gas. Two template-based preparation methods were developed for this purpose. One method was based on soft templates (microemulsion) and the other on hard templates (carbon). Supports known for their stability, magnesia and hexaaluminate, were prepared using the developed methods. Catalytically active materials, perovskite (LaMnO3) and ceria (CeO2), were added to the supports in order to obtain catalysts with high activities and stabilities. The supports were impregnated with active materials by using a conventional technique as well as by using the microemulsion technique. It was shown that the microemulsion method can be used to prepare catalysts with higher activity compared to the conventional methods. Furthermore, by using a microemulsion to apply active materials onto the support a significantly higher activity was obtained than when using the conventional impregnation technique. Since the catalysts will operate in the catalytic combustor for extended periods of time under harsh conditions, an aging study was performed on selected catalysts prepared by the microemulsion technique. The stability of the catalysts was assessed by measuring the activity before and after aging at 1000 C in humid air for 100 h. One of the most stable catalysts reported in the literature, LMHA (manganese-substituted lanthanum hexaaluminate), was included in the study for comparative purposes. The results showed that LMHA deactivated much more strongly compared to several of the catalysts consisting of ceria supported on lanthanum hexaaluminate prepared by the developed microemulsion method. Carbon templating was shown be a very good technique for the preparation of high-surface-area hexaaluminates with excellent sintering resistance. It was found that the pore size distribution of the carbon used as template was a crucial parameter in the preparation of hexaaluminates. When a carbon with small pores was used as template, the formation of the hexaaluminate crystals was strongly inhibited. This resulted in a material with poor sintering resistance. On the other hand, if a carbon with larger pores was used as template, it was possible to prepare materials with hexaaluminate as the major phase. These materials were, after accelerated aging at 1400 C in humid air, shown to retain surface areas twice as high as reported for conventionally prepared materials.
Application of Magnetic Nanoparticles for the removal of turbidity and total nitrogen from sewage wastewater : Modelling studies
Application of Magnetic Nanoparticles for the removal of turbidity and total nitrogen from sewage... more Application of Magnetic Nanoparticles for the removal of turbidity and total nitrogen from sewage wastewater : Modelling studies
Preparation of hexaaluminate
Study of th selectivity-governing parameters in the cobalt-catalysed Fischer-Tropsch reaction
In order to secure the energy supply to an increasing population and at the same time limit the d... more In order to secure the energy supply to an increasing population and at the same time limit the damage to Earth, i.e. avoiding a fatal climate change as a result of anthropogenic emissions of greenhouse gases (primarily CO2), immediate action is necessary. This includes reducing the energy consumption, increasing the energy conversion efficiency, and using renewable energies. The transport sector is the one most dependent on fossil energy and it stands for a significant part of the energy consumption in the world. For instance, in EU-25 transportation stands for 30 % of the total final energy consumption and relies to 98 % on oil. Being the only renewable energy possible to convert into liquid fuels biomass, as a means for reducing the CO2 emissions from the transport sector, will play an important role in the near future. The conversion of biomass into transportation fuels is preferentially done via gasification followed by the fuel synthesis. The whole production chain from biomass to final fuel is very dependent on R&D, in order to become competitive with the fossil fuels. Fischer-Tropsch (FT) diesel made from biomass is a viable option for reducing the CO2 emissions from transportation since it may be blended with conventional diesel in any concentration. Furthermore, since its composition is almost the same as of petroleum-based diesel (although cleaner) the same distribution system and engines may be used, which facilitates its introduction on the market. This thesis presents the results of the laboratory work performed in 2003 – 2007 at the Department of Chemical Technology, KTH, and at the Department of Chemical Engineering, NTNU (the Norwegian University of Science and Technology) in Trondheim. Part of the work has been performed in close cooperation with the Department of Chemical and Biological Engineering at Chalmers University of Technology. All FT experiments were performed in a fixed-bed reactor at 210 oC and 20 bar. Pure mixtures of H2, CO and N2 were used as feed to the reactor. Steam was also occasionally introduced. Selectivity to C5+ was used as a measure of the catalysts’ ability to grow long-chain hydrocarbons, which is desirable when diesel is the product aimed for. The first part of the thesis deals with the direct conversion of a H2-poor syngas, which is obtained upon gasification of biomass, into FT hydrocarbons. “H2-poor” means that the H2/CO ratio is lower than what is required by the stoichiometry (~ 2.1) of the FT synthesis (reaction 1). In order to increase the H2/CO ratio to the required one, internal water-gas-shift (WGS) is needed (reaction 2). FT: CO + 2H2 “-CH2-“ + H2O (1) WGS: CO + H2O CO2 + H2 (2) The H2/CO usage ratio has been used as a measure for the internal WGS activity, it is defined as follows: where S is the selectivity (of total C-containing products), and the factor F indicates the number of H2 moles required for one CO mole to form the product (e.g. for producing high molecular weight n-paraffins, 2 moles of H2 per mole of CO are required). For the fraction C2 – C4, F will have different values depending on the selectivity to C2, C3 and C4, and it also depends on the olefin/paraffin ratios for those hydrocarbons. In order to reach the highest once-through conversion of the syngas, the H2/CO usage ratio should be equal to the inlet H2/CO ratio. The lower the usage ratio, the higher the relative WGS activity. The combined FT and WGS reactions with H2-poor syngas have been tested for 12 wt% Co and 12 wt% Co – 0.5 wt% Re catalysts supported on γ-Al2O3. It was found that with lower H2/CO ratios in the feed, the syngas conversion and the CH4 selectivity decreased, while the C5+ selectivity and olefin/paraffin ratio for C2-C4 increased slightly. The WGS activity was low for all catalysts, implying a H2/CO usage ratio close to the stoichiometric one (2.1), even for inlet H2/CO ratios of 1.5 and 1.0. By incorporating significant amounts of Fe (20 % of total metal) in the Co catalyst referred to above (by co-impregnation) in order to achieve a 12 wt% bimetal loading on γ-Al2O3, a slightly lower usage ratio was obtainable (1.92) for an inlet ratio of 1.0 for dry conditions. Different Fe:Co ratios ranging from 100 % Fe to 100 % Co (12 wt% bimetal) were tested for an inlet H2/CO ratio of 1.0. The characterisation results indicated that Fe was enriched at the surface, hence covering the more FT-active Co sites, even at low percentage Fe. Not even upon significant replacement of Co by Fe (≥ 20 %) were the usage ratios for dry conditions lowered to any significant extent. The WGS reaction at the low temperature used could be boosted by addition of external water. However, since the catalysts with the highest WGS activity had surface enrichment of Fe, high water partial pressures negatively affect the FT rate and also lead to rapid deactivation by re-oxidation of the FT-active iron phases (iron carbides) or by sintering. Surprisingly, also the WGS activity rapidly…
Topics in Catalysis
In this study, an experimental investigation concerning exhaust gas catalysts for heavy-duty dies... more In this study, an experimental investigation concerning exhaust gas catalysts for heavy-duty diesel engines fuelled by natural gas or biogas is presented. Miniature monoliths, 2.5 wt% Pd/Al2O3, have been prepared, characterised and tested. Various methods have been used in order to obtain different palladium particle sizes, including incipient wetness and microemulsion technique. Crystallite sizes between 2 and 40 nm were obtained. We observed that the metal particle size influences the activity for methane oxidation. Moreover, the homogeneity of the active material was found to affect the reaction rate.
Fuel, 2013
" Effect of CO 2 -containing syngas for activity and selectivity in HAS was studied. " Catalyst t... more " Effect of CO 2 -containing syngas for activity and selectivity in HAS was studied. " Catalyst testing was done during 360 h on stream. " CO 2 -containing syngas reduces alcohol chain growth and lowers product yield.
Catalysis Today, 1994
Deactivation of Ni-based catalysts was investigated during CO methanation over different supporte... more Deactivation of Ni-based catalysts was investigated during CO methanation over different supported catalysts. X-ray diffraction and temperature-programmed hydrogenation analyses were used to investigate nickel particle sintering and carbon formation during the first 24 hours on stream. Titaniasupported catalysts presented high resistance towards carbon deposition and nickel particle growth in comparison with the other tested catalysts. Particle size effects on these two deactivation causes were also evaluated. It was shown that carbon formation rates are higher on bigger crystal particles. However, it was found that titania-supported nickel catalysts reduced at high temperatures show the opposite effect. This difference is most probably due to a stronger interaction between nickel and TiO x (x<2) species on smaller crystals which changes the CO dissociation properties and, in consequence, carbon formation rates.
Catalysis Today, 1999
FCC catalyst additives for sulfur-compound cracking with the ability to reduce sulfur in gasoline... more FCC catalyst additives for sulfur-compound cracking with the ability to reduce sulfur in gasoline have been produced by depositing various metals and metal oxides on different supports using the microemulsion technique. Three groups of additives have been studied. First, Zn on different supports: alumina, titania, and hydrotalcite. Second, different metals on alumina: Zn, Mn and Zr, and third, two different metals on hydrotalcite: Zn and Co. The additives were blended to 10 wt% with a reference FCC-catalyst. All the additives give lower yields of gasoline than the reference catalyst itself. The loss in gasoline is due to an increased amount of gas production and/or increase in coke production. Concerning the sulfur reduction, the order of activity of the four best additives is the following: Zn/hydrotalcite > ZrO/alumina > Zn/titania > Mn/alumina. Zn/hydrotalcite has a value of ≈80% reduction of sulfur in sulfur-spiked gasoline at the microactivity test (MAT)-level.
Catalytic partial oxidation of methane over Ni-, Co- and Fe-based catalysts
Catalysis Today, 1998
Partial oxidation of methane to synthesis gas has been investigated over Fe-, Co-and Ni-based cat... more Partial oxidation of methane to synthesis gas has been investigated over Fe-, Co-and Ni-based catalysts in fixed bed reactor in view of a possible application in a fluidized bed reactor. Catalytic testing of the oxidic catalysts show an increasing activity for total oxidation of methane in ...
Fuel-rich catalytic combustion of methane in zero emissions power generation processes
Catalysis Today, 2006
The catalyst support material was found to influence the light-off temperature significantly, whi... more The catalyst support material was found to influence the light-off temperature significantly, which increased in the following order Rh/Ce-ZrO 2 < Rh/ZrO 2 < Rh/α-Al 2 O 3 . The Rh loading, however, only had a minor influence. The high activity of Rh/Ce-ZrO 2 is probably related ...
Uploads
Papers by Magali Boutonnet