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Maria Cristina Annesini - One of the best experts on this subject based on the ideXlab platform.
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modeling of autothermal Methane Steam Reforming comparison of reactor configurations
Chemical Engineering and Processing, 2016Co-Authors: Maria Anna Murmura, M Diana, R Spera, Maria Cristina AnnesiniAbstract:Abstract In the present work, two systems for the coupling of Methane Steam Reforming and Methane combustion have been studied and compared. In the first system considered, the two reactions are thermally coupled but take place in separate volumes. Particular attention has been placed on the choice of operating conditions in order to maximize the efficiency and safety of the process. The second system considered consists in a modification of the process of autothermal Reforming, distributing the oxygen feed to the reactor along its axis. The results obtained have been compared with the performance of a reactor in which the oxidation reaction is carried out by injecting oxygen in different points along the reactor. The performance of the two systems has been compared with that of an autothermal reformer, in which the entire oxygen feed is mixed with Steam and Methane entering the reactor. The analysis of the different systems has focused on the temperature profiles that develop within the reactors, the amount of hydrogen produced per mole of Methane fed, and the possibility of carrying out the process without entering flammability limits.
Liang Gong - One of the best experts on this subject based on the ideXlab platform.
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numerical analysis of hydrogen production via Methane Steam Reforming in porous media solar thermochemical reactor using concentrated solar irradiation as heat source
Energy Conversion and Management, 2014Co-Authors: Fuqiang Wang, Yong Shuai, Liang GongAbstract:The calorific value of syngas can be greatly upgraded during the Methane Steam Reforming process by using concentrated solar energy as heat source. In this study, the Monte Carlo Ray Tracing (MCRT) and Finite Volume Method (FVM) coupling method is developed to investigate the hydrogen production performance via Methane Steam Reforming in porous media solar thermochemical reactor which includes the mass, momentum, energy and irradiative transfer equations as well as chemical reaction kinetics. The local thermal non-equilibrium (LTNE) model is used to provide more temperature information. The modified P1 approximation is adopted for solving the irradiative heat transfer equation. The MCRT method is used to calculate the sunlight concentration and transmission problems. The fluid phase energy equation and transport equations are solved by Fluent software. The solid phase energy equation, irradiative transfer equation and chemical reaction kinetics are programmed by user defined functions (UDFs). The numerical results indicate that concentrated solar irradiation on the fluid entrance surface of solar chemical reactor is highly uneven, and temperature distribution has significant influence on hydrogen production.
Jens Sehested - One of the best experts on this subject based on the ideXlab platform.
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Methane Steam Reforming Kinetics for a Rhodium-Based Catalyst
Catalysis Letters, 2010Co-Authors: Jon Geest Jakobsen, Martin Jakobsen, Ib Chorkendorff, Jens SehestedAbstract:Methane Steam Reforming is the key reaction to produce synthesis gas and hydrogen at the industrial scale. Here the kinetics of Methane Steam Reforming over a rhodium-based catalyst is investigated in the temperature range 500–800 °C and as a function of CH_4, H_2O and H_2 partial pressures. The Methane Steam Reforming reaction cannot be modeled without taking CO and H coverages into account. This is especially important at low temperatures and higher partial pressures of CO and H_2. For Methane CO_2 Reforming experiments, it is also necessary to consider the repulsive interaction of CO that lowers the adsorption energy at high CO coverage. The CO–CO interaction is supported by comparison with fundamental surface science studies. Graphical Abstract Experimental results ( points ), Langmuir–Hinshelwood kinetic modeling ( lines ) and descriptive power law constants for the Methane dependency in the Methane Steam Reforming reaction on a Rh catalyst.
A Siddle - One of the best experts on this subject based on the ideXlab platform.
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intrinsic reaction kinetics of Methane Steam Reforming on a nickel zirconia anode
Journal of Power Sources, 2000Co-Authors: Andrew Dicks, K D Pointon, A SiddleAbstract:Abstract For the purposes of optimising important system parameters in direct internally Reforming (DIR) solid oxide fuel cell (SOFC) systems, a detailed knowledge of the Methane Steam Reforming rate on the anode is needed. In order to shed light on the present poorly understood kinetics, a study of the Methane Steam Reforming rate given by a typical thin electrolyte-supported nickel/zirconia SOFC anode has been carried out using a tubular plug flow differential reactor. These tests were essentially gradientless. The reaction rate was studied as a function of temperature (700–1000°C) and the partial pressure of Methane (2–40 kPa), hydrogen (10–70 kPa) and Steam (10–70 kPa). The total pressure was nominally 1 atm. The reaction was first order in Methane with a weak positive effect of hydrogen, and a stronger negative effect of Steam. The kinetics were complicated by the fact that reaction orders in hydrogen and Steam were either temperature dependent and/or depended on the partial pressures of other components in the gas mixture. Furthermore, Arrhenius-type plots gave gradients which were dependent on the Steam partial pressure. It is clear from this study that the reaction cannot be represented as simply as is generally attempted in the literature. An improved rate equation has been derived.
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Intrinsic reaction kinetics of Methane Steam Reforming on a nickel/zirconia anode
Journal of Power Sources, 2000Co-Authors: Andrew Dicks, K D Pointon, A SiddleAbstract:Abstract For the purposes of optimising important system parameters in direct internally Reforming (DIR) solid oxide fuel cell (SOFC) systems, a detailed knowledge of the Methane Steam Reforming rate on the anode is needed. In order to shed light on the present poorly understood kinetics, a study of the Methane Steam Reforming rate given by a typical thin electrolyte-supported nickel/zirconia SOFC anode has been carried out using a tubular plug flow differential reactor. These tests were essentially gradientless. The reaction rate was studied as a function of temperature (700–1000°C) and the partial pressure of Methane (2–40 kPa), hydrogen (10–70 kPa) and Steam (10–70 kPa). The total pressure was nominally 1 atm. The reaction was first order in Methane with a weak positive effect of hydrogen, and a stronger negative effect of Steam. The kinetics were complicated by the fact that reaction orders in hydrogen and Steam were either temperature dependent and/or depended on the partial pressures of other components in the gas mixture. Furthermore, Arrhenius-type plots gave gradients which were dependent on the Steam partial pressure. It is clear from this study that the reaction cannot be represented as simply as is generally attempted in the literature. An improved rate equation has been derived.
Maria Anna Murmura - One of the best experts on this subject based on the ideXlab platform.
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modeling of autothermal Methane Steam Reforming comparison of reactor configurations
Chemical Engineering and Processing, 2016Co-Authors: Maria Anna Murmura, M Diana, R Spera, Maria Cristina AnnesiniAbstract:Abstract In the present work, two systems for the coupling of Methane Steam Reforming and Methane combustion have been studied and compared. In the first system considered, the two reactions are thermally coupled but take place in separate volumes. Particular attention has been placed on the choice of operating conditions in order to maximize the efficiency and safety of the process. The second system considered consists in a modification of the process of autothermal Reforming, distributing the oxygen feed to the reactor along its axis. The results obtained have been compared with the performance of a reactor in which the oxidation reaction is carried out by injecting oxygen in different points along the reactor. The performance of the two systems has been compared with that of an autothermal reformer, in which the entire oxygen feed is mixed with Steam and Methane entering the reactor. The analysis of the different systems has focused on the temperature profiles that develop within the reactors, the amount of hydrogen produced per mole of Methane fed, and the possibility of carrying out the process without entering flammability limits.