Methane Steam Reforming Over LaCrŒ1Œ-ŒxNiŒxOŒ3 Perovskite Catalysts PDF Download

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Languages : en
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Author: Ram Chandra Paul
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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The kinetics of the steam reforming of methane over perovskite catalysts with the formula LaCr1-xNixO3 (x = 0.25 & 0.40) have been examined over a wide range of temperatures (500°C to 1000°C) and atmospheric pressure. These catalysts work well from 700 to 900°C for methane conversion (space velocity = 13,500 hr-1 , and gas composition is CH4 : H2 : H2 O : Ar = 2 : 3 : 6 : 30), the higher nickel content (Ni = 0.40) catalyst is more active than the lower nickel content (Ni = 0.25) catalyst. The water-gas shift reaction is close to equilibrium, while the steam reforming reaction is not at equilibrium for the conditions studied. Activity behaviour is in agreement with 'Marko's' methane oxidation result (1 ). However, these catalysts are unstable in the reforming environment, as they partially reduce to elemental nickel at high temperatures (worked up to 1000°C. Structural changes (from orthorhombic to rhombohedral) occur at lower temperatures (investigated up to 750°C). The higher nickel content catalysts are less stable than the lower nickel content catalysts.

Author: Fanglin Che
Publisher:
ISBN:
Category : Catalysis
Languages : en
Pages : 510

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Finally, we provide a 'bottom-up' fundamental insight into two debates regarding methane activation over Ni-based catalysts, including the role of a low concentration of carbon or carbide species and the role of electric fields in a fuel cell system. Our DFT results suggest that inducing a local change of the Ni oxidation states can markedly enhance methane activation. Overall, this thesis will be instructive for the design of heterogeneous reactors with tunable metal oxidation states via the modification of the surface carbon or the interface carbide complex as well as the addition of reaction environment factors (e.g., electric fields).

Author: Veerapong Viriyapanya
Publisher:
ISBN: 9789741730155
Category : Catalytic reforming
Languages : en
Pages : 170

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To study the kinetics of methane steam reforming on Ni0.03Mg0.97O solid solution catalyst in fixed bed cylindrical reactor. The spherical catalyst of 22 m2/g specific area and 589.64 kg/m3 density were packed in cylindrical reactor of 3 cm. diameter and 66 cm. long. The effect of temperature, H2O/CH4 ratio, methane feed rate, stream feed rate and catalyst weight on methane conversion and reaction rate was investigated. The rate equation of steam reforming in case of excess steam was expressed in first order of methane. Non-excess steam showed the rate equation of reaction, which was expressed in order of 1 for methane and 0.5 for steam. The methane steam reforming was first order of methane explained by Langmuir-Hinshelwood model and the chemical reaction was controlling step of reaction rate. Comparison of the experimental data with thermodynamics equilibrium was consistent. The thermodynamics model of reaction could be proposed in methane steam reforming and water - gas shift reactions.

Author: J.L.G. Fierro
Publisher: CRC Press
ISBN: 142002812X
Category : Science
Languages : en
Pages : 808

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The chemistry of metals has traditionally been more understood than that of its oxides. As catalytic applications continue to grow in a variety of disciplines, Metal Oxides: Chemistry and Applications offers a timely account of transition-metal oxides (TMO), one of the most important classes of metal oxides, in the context of catalysis. The

Author: Sudarsanam Putla
Publisher: ACS Symposium
ISBN: 9780841298804
Category : Science
Languages : en
Pages : 608

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Advances and applications of nanosized catalysts Over the last five years, tremendous advances have been made in heterogeneous catalysis. In particular, catalysts' design from the bulk to nano-scale (1-100 nm), with desirable active sites, has received great attention in current catalysis research with the aim to fill the gap between homogeneous and heterogeneous catalysis. This volume focuses on applications of nanosized catalysts. Articles describe characterization, synthesis, and applications in biomass conversion, auto-exhaust purification, selective oxidation/hydrogenation, syngas conversion, and other important reactions. Readers will find examples of catalysts designed to be tunable for specific outcomes, inspiring their research. Scientists and engineers in chemistry, materials science, nanotechnology, and chemical engineering will find this volume useful.

Author: David Briggs
Publisher:
ISBN:
Category : Auger effect
Languages : en
Pages : 776

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Author: Chang Geun Yoo
Publisher:
ISBN: 9780841298453
Category : Lignin
Languages : en
Pages : 314

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Emerging applications of lignin Lignin has great potential as a sustainable, renewable resource for aromatic molecules that can be used in downstream applications. However, its natural heterogeneity and complexity are substantial barriers to its efficient utilization. Industrial lignin, a byproduct from the pulping and biorefinery industries, is usually burned or directly discharged as waste. This work provides a comprehensive exploration of recent lignin utilization strategies with chapters written by experts from agricultural science and engineering, biotechnology, biology, catalysis, chemical engineering, chemistry, wood science, and other related fields.

Author: Chintamani Nagesa Ramachandra Rao
Publisher: VCH Publishers
ISBN:
Category : Science
Languages : en
Pages : 360

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Author: Sudarsanam Putla
Publisher:
ISBN: 9780841298781
Category : Science
Languages : en
Pages : 314

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Fundamentals and applications of single-atom catalysts Over the last five years, tremendous advances have been made in heterogeneous catalysis. In particular, catalysts' design from the bulk to single-atom scale (0.1-0.9 nm), with desirable active sites, has received great attention in current catalysis research with the aim to fill the gap between homogeneous and heterogeneous catalysis. This volume focuses on applications of single-atom catalysts. Articles describe principles of single-atom catalysts as well as applications in biomass conversion, water purification, CO2 upgrading, and other specific reactions. Readers will find examples of catalysts designed to be tunable for specific outcomes, inspiring their research. Scientists and engineers in chemistry, materials science, nanotechnology, and chemical engineering will find this volume useful.