Search results for: Sven Järås

Items from 1 to 20 out of 35 results

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Further insights into methane and higher hydrocarbons formation over cobalt-based catalysts with γ-Al2O3, α-Al2O3 and TiO2 as support materials

Sara Lögdberg, Jia Yang, Matteo Lualdi, John C. Walmsley, more

Journal of Catalysis > 2017 > 352 > C > 515-531

A range of cobalt-based catalysts varying in Co loading and prepared by incipient wetness impregnation of traditional support materials (γ-Al₂O₃, α-Al₂O₃ and TiO₂), have been studied in the Fischer-Tropsch reaction at industrially relevant process conditions (483K, 20bar, H₂/CO=2.1). A high selectivity to C₅₊ hydrocarbons (S_C5+) is to a great extent connected with a high site activity, but not exclusively...

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Fischer–Tropsch Synthesis Over Zr-Promoted Co/γ-Al₂O₃ Catalysts

Javier Barrientos, Victoria Garcilaso, Baldassarre Venezia, Atte Aho, more

Topics in Catalysis > 2017 > 60 > 17-18 > 1285-1298

Two Zr-modified alumina supports were synthetized containing the same amount of Zr but a different distribution of this modifier over the alumina surface. These supports, together with the unmodified alumina carrier, were used to prepare three cobalt-based catalysts which were characterized and tested under relevant Fischer–Tropsch conditions. The three catalysts presented very similar porosity and...

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Deactivation of Ni/γ-Al₂O₃ Catalysts in CO Methanation: Effect of Zr, Mg, Ba and Ca Oxide Promoters

Javier Barrientos, Niklas Gonzalez, Magali Boutonnet, Sven Järås

Topics in Catalysis > 2017 > 60 > 17-18 > 1276-1284

Catalyst deactivation is one of the major concerns in the production of substitute natural gas (SNG) via CO methanation. Catalysts in this application need to be active at low temperatures, resistant to polymeric carbon formation and stable at high temperatures and steam partial pressures. In the present work, a series of alumina-supported nickel catalysts promoted with Zr, Mg, Ba or Ca oxides were...

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Hydroconversion of paraffinic wax over platinum and palladium catalysts supported on silica–alumina

Rodrigo Suárez París, Mario Enrico L’Abbate, Leonarda Francesca Liotta, Vicente Montes, more

Catalysis Today > 2016 > 275 > C > 141-148

Two bifunctional catalysts consisting of platinum or palladium supported on amorphous silica–alumina were prepared and tested in hydrocracking/hydroisomerization of paraffinic wax. The performance of both noble metals was studied at the following reaction conditions: P=35bar; T=300–330°C; H₂/wax=0.1wt/wt; WHSV=1–4h⁻¹. The platinum sample was more active in hydrocracking of C₂₂₊ compounds and more...

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Syngas conversion to ethanol over a mesoporous Cu/MCM-41 catalyst: Effect of K and Fe promoters

Luis Lopez, Vicente Montes, Henrik Kušar, Saul Cabrera, more

Applied Catalysis A: General > 2016 > 526 > C > 77-83

Transportation fuels such as ethanol can be obtained through thermochemical processing of biomass. Interest in the development of more selective catalysts for the conversion of biomass-derived syngas (H₂+CO) to ethanol is increasing in both academia and industry. In this work, we have evaluated the performances of K and Fe as metal promoters of a mesoporous Cu/MCM-41 catalyst and their effects on...

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Higher alcohol synthesis over nickel-modified alkali-doped molybdenum sulfide catalysts prepared by conventional coprecipitation and coprecipitation in microemulsions

Rodrigo Suárez París, Vicente Montes, Magali Boutonnet, Sven Järås

Catalysis Today > 2015 > 258 > P2 > 294-303

Ethanol and higher alcohols are one of the most interesting alternatives to replace fossil fuels in the transportation sector. Nickel-modified alkali-doped molybdenum sulfide is a potential catalyst for the conversion of syngas to mixed alcohols. In this work, K-Ni-MoS₂ catalysts were synthetized by coprecipitation in aqueous solution or in microemulsions, followed by alkali doping. The influence...

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Effect of syngas conversion and catalyst reduction temperature in the synthesis of ethanol: concentration of water vapor in mesoporous Rh/MCM-41 catalyst

Luis Lopez, Jorge Velasco, Saul Cabrera, Magali Boutonnet, more

Catalysis Communications > 2015 > 69 > Complete > 183-187

Rh-based catalysts typically show low selectivity to CO₂ in the synthesis of ethanol from syngas. However, a novel mesoporous Rh/MCM-41 catalyst shows high selectivity to CO₂ in a large range of syngas conversions; 1% to 68%, regulated by adjusting the operation conditions (270–430°C, 30–90bar and 6000–40,000ml_(syngas)/g_cath). The same effect is obtained at different catalyst reduction temperatures...

article

Catalytic partial oxidation of methane over nickel and ruthenium based catalysts under low O2/CH4 ratios and with addition of steam

Jorge A. Velasco, Cristhian Fernandez, Luis Lopez, Saul Cabrera, more

Fuel > 2015 > 153 > C > 192-201

Catalytic partial oxidation (CPO) of methane to synthesis gas at low O₂/CH₄ ratios and in the presence of steam was investigated over nickel and ruthenium catalysts supported on hydrotalcite-derived materials. The influence of catalyst properties and composition on activity, temperature profile and deactivation by carbon formation was examined. All catalyst presented high methane conversions, close...

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Effect of methanol addition on higher alcohol synthesis over modified molybdenum sulfide catalysts

Rodrigo Suárez París, Magali Boutonnet, Sven Järås

Catalysis Communications > 2015 > 67 > Complete > 103-107

One of the main problems in higher alcohol synthesis is the poor product distribution. Cofeeding of methanol, together with the synthesis gas, has been suggested in order to increase the yield of ethanol and higher alcohols. In this work, the effect of methanol addition on K–MoS ₂ and K–Ni–MoS ₂ catalysts was studied at 71bar, 340°C and GHSV=6000NmL/h·g _catalyst . Under these...

article

Synthesis gas production for GTL applications: Thermodynamic equilibrium approach and potential for carbon formation in a catalytic partial oxidation pre-reformer

Jorge A. Velasco, Luis Lopez, Saul Cabrera, Magali Boutonnet, more

Journal of Natural Gas Science and Engineering > 2014 > 20 > Complete > 175-183

The present work is focused on synthesis gas production for Gas to Liquids (GTL) applications. A thermodynamic equilibrium approach has been chosen in order to address the methane reforming processes in presence of steam and oxygen (i.e. autothermal reforming “ATR” and catalytic partial oxidation “CPO”). The effect of operational variables on the performance of the reforming units has been analyzed...

article

Effect of metal loading on activity, selectivity and deactivation behavior of Pd/silica–alumina catalysts in the hydroconversion of n-hexadecane

Francesco Regali, Leonarda Francesca Liotta, Anna Maria Venezia, Vicente Montes, more

Catalysis Today > 2014 > 223 > Complete > 87-96

Bifunctional catalysts consisting of palladium on amorphous silica–alumina with different metal loadings (0wt% to 1.2wt%) were compared in the hydrocracking/hydroisomerization of n-hexadecane. The reaction conditions were: pressure=30bar; temperature=310°C; hydrogen-to-hexadecane feed molar ratio=10. Metal loading was found to have a remarkable influence on the initial deactivation rate, which could...

article

Microemulsion prepared magnetic nanoparticles for phosphate removal: Time efficient studies

Ramnath Lakshmanan, Chuka Okoli, Magali Boutonnet, Sven Järås, more

Journal of Environmental Chemical Engineering > 2014 > 2 > 1 > 185-189

The present study investigates the effective removal of phosphate in sewage wastewater using magnetic iron oxide nanoparticles (MION). The microemulsion-prepared magnetic iron oxide nanoparticles (ME-MION) of around 7–10nm was synthesized using water-in-oil microemulsion method. The interaction of ME-MION and phosphate was studied using In situ FT-IR technique. Batch experiments were carried out with...

article

Hydroconversion of n-hexadecane on Pt/silica-alumina catalysts: Effect of metal loading and support acidity on bifunctional and hydrogenolytic activity

Francesco Regali, Leonarda Francesca Liotta, Anna Maria Venezia, Magali Boutonnet, more

Applied Catalysis A: General > 2014 > 469 > C > 328-339

Bifunctional catalysts based on platinum and amorphous silica–alumina were studied in the hydroconversion of n-hexadecane. The influence of platinum loading and support acidity on activity and selectivity were assessed. The contribution of hydrogenolysis reactions on top of bifunctional hydrocracking was shown to depend not only on metal loading, but also on the effect of support acidity on the intrinsic...

article

Higher alcohols from syngas using a K/Ni/MoS2 catalyst: Trace sulfur in the product and effect of H2S-containing feed

Robert Andersson, Magali Boutonnet, Sven Järås

Fuel > 2014 > 115 > Complete > 544-550

Two types of experiments have been performed related to the higher alcohol synthesis from syngas over a K–Ni–MoS ₂ catalyst which beforehand has been operated for 1000h on stream in sulfur-free syngas. In the first experimental part, sulfur-free syngas was used as feed and the condensed liquid product was found to contain 67ppmw sulfur, while the sulfur concentration in the gas was 19ppmv...

article

Hydrocracking of n-hexadecane on noble metal/silica–alumina catalysts

Francesco Regali, Magali Boutonnet, Sven Järås

Catalysis Today > 2013 > 214 > Complete > 12-18

Bifunctional catalysts consisting of platinum or palladium on amorphous silica–alumina were prepared and tested in the hydrocracking of n-hexadecane (n-C ₁₆ H ₃₄ ). Product selectivities toward mono-branched and multi-branched feed isomers and cracking products have been determined in a wide range of conversions, varying liquid hourly space velocity at constant operating parameters...

article

On the effect of water on the Fischer–Tropsch rate over a Co-based catalyst: The influence of the H2/CO ratio

Matteo Lualdi, Sara Lögdberg, Magali Boutonnet, Sven Järås

Catalysis Today > 2013 > 214 > Complete > 25-29

The effect of water partial pressure on the Fischer–Tropsch (FT) rate of a cobalt catalyst supported on narrow-pore γ-Al ₂ O ₃ was investigated at industrially relevant process conditions (483K, 30bar, pellet size: 53–90μm). Inlet water partial pressure was varied up to 9bar by external water vapour addition at different H ₂ /CO molar ratios ranging from 1 to 3.The effect of...

article

Effect of CO2 in the synthesis of mixed alcohols from syngas over a K/Ni/MoS2 catalyst

Robert Andersson, Magali Boutonnet, Sven Järås

Fuel > 2013 > 107 > C > 715-723

An unsupported K–Ni–MoS₂ catalyst for higher alcohol synthesis from syngas (H₂/CO) has been studied during 360h on stream. It shows a gradual increase in activity with time on stream and some possible reasons for this are discussed in the paper. The main focus of this paper was to study the on the effect of CO₂-containing syngas, relative CO₂-free syngas under identical reaction conditions and identical...

article

Effect of magnetic iron oxide nanoparticles in surface water treatment: Trace minerals and microbes

Ramnath Lakshmanan, Chuka Okoli, Magali Boutonnet, Sven Järås, more

Bioresource Technology > 2013 > 129 > C > 612-615

The existing water treatment process often uses chemicals, which is of high health and environmental concern. The present study focused on the efficiency of microemulsion prepared magnetic iron oxide nanoparticles (ME-MIONs) and protein-functionalized nanoparticles (MOCP+ME-MIONs) in water treatment. Their influence on mineral ions and microorganisms present in the surface water from lake Brunnsviken...

article

Deactivation of a Pt/Silica–Alumina Catalyst and Effect on Selectivity in the Hydrocracking of n-Hexadecane

Francesco Regali, Rodrigo Suárez París, Atte Aho, Magali Boutonnet, more

Topics in Catalysis > 2013 > 56 > 9-10 > 594-601

The deactivation behavior of a bifunctional catalyst consisting of platinum on amorphous silica–alumina was studied in the hydrocracking of n-hexadecane. The initial decline in activity and the change in selectivity were monitored at the following reaction conditions: pressure = 30 bar; temperature = 310 °C; hydrogen-to-hexadecane feed molar ratio = 10. Initially, hexadecane conversion and selectivity...

article

Co/SiO2 catalysts for Fischer–Tropsch synthesis; effect of Co loading and support modification by TiO2

Anna Maria Venezia, Valeria La Parola, Leonarda F. Liotta, Giuseppe Pantaleo, more

Catalysis Today > 2012 > 197 > 1 > 18-23

The influence of cobalt loading and titania addition to the silica support on Fischer–Tropsch synthesis activity is investigated over two series of catalysts with Co loading of 6wt% and 12wt%. The pure silica support is prepared by sol–gel procedure in acid conditions. The modification by TiO ₂ is performed by grafting with titanium isopropoxide. The catalysts are prepared by wet-impregnation...

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Search results for: Sven Järås

Further insights into methane and higher hydrocarbons formation over cobalt-based catalysts with γ-Al2O3, α-Al2O3 and TiO2 as support materials

Fischer–Tropsch Synthesis Over Zr-Promoted Co/γ-Al₂O₃ Catalysts

Deactivation of Ni/γ-Al₂O₃ Catalysts in CO Methanation: Effect of Zr, Mg, Ba and Ca Oxide Promoters

Hydroconversion of paraffinic wax over platinum and palladium catalysts supported on silica–alumina

Syngas conversion to ethanol over a mesoporous Cu/MCM-41 catalyst: Effect of K and Fe promoters

Higher alcohol synthesis over nickel-modified alkali-doped molybdenum sulfide catalysts prepared by conventional coprecipitation and coprecipitation in microemulsions

Effect of syngas conversion and catalyst reduction temperature in the synthesis of ethanol: concentration of water vapor in mesoporous Rh/MCM-41 catalyst

Catalytic partial oxidation of methane over nickel and ruthenium based catalysts under low O2/CH4 ratios and with addition of steam

Effect of methanol addition on higher alcohol synthesis over modified molybdenum sulfide catalysts

Synthesis gas production for GTL applications: Thermodynamic equilibrium approach and potential for carbon formation in a catalytic partial oxidation pre-reformer

Effect of metal loading on activity, selectivity and deactivation behavior of Pd/silica–alumina catalysts in the hydroconversion of n-hexadecane

Microemulsion prepared magnetic nanoparticles for phosphate removal: Time efficient studies

Hydroconversion of n-hexadecane on Pt/silica-alumina catalysts: Effect of metal loading and support acidity on bifunctional and hydrogenolytic activity

Higher alcohols from syngas using a K/Ni/MoS2 catalyst: Trace sulfur in the product and effect of H2S-containing feed

Hydrocracking of n-hexadecane on noble metal/silica–alumina catalysts

On the effect of water on the Fischer–Tropsch rate over a Co-based catalyst: The influence of the H2/CO ratio

Effect of CO2 in the synthesis of mixed alcohols from syngas over a K/Ni/MoS2 catalyst

Effect of magnetic iron oxide nanoparticles in surface water treatment: Trace minerals and microbes

Deactivation of a Pt/Silica–Alumina Catalyst and Effect on Selectivity in the Hydrocracking of n-Hexadecane

Co/SiO2 catalysts for Fischer–Tropsch synthesis; effect of Co loading and support modification by TiO2

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