The Experts below are selected from a list of 456 Experts worldwide ranked by ideXlab platform
Asterios Gavriilidis - One of the best experts on this subject based on the ideXlab platform.
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Catalytic combustion assisted methane steam reforming in a Catalytic Plate Reactor
Chemical Engineering Science, 2003Co-Authors: M Zanfir, Asterios GavriilidisAbstract:A theoretical study of methane steam reforming coupled with methane Catalytic combustion in a Catalytic Plate Reactor (CPR) based on a two-dimensional model is presented. Plates with coated catalyst layers of order of micrometers at distances of order of millimetres offer a high degree of compactness and minimise heat and mass transport resistances. Choosing similar operating conditions in terms of inlet composition and temperature as in industrial reformer allows a direct comparison of CPRs with the latter. It is shown that short distance between heat source and heat sink increases the efficiency of heat exchange. Transverse temperature gradients do not exceed 0.5 K across the wall and 40 K across the gas-phase, in contrast to 250 K difference in temperature of outside wall and mean gas phase temperature inside the tube usually observed in conventional reformers. The effectiveness factors for the reforming chemical reactions are about one order of magnitude higher than in conventional processes. Minimisation of heat and mass transfer resistances results in reduction of Reactor volume and catalyst weight by two orders of magnitude as compared to industrial reformer. Alteration of distance between Plates in the range 1-4 mm does not result in significant difference in Reactor performance, if made at constant inlet flowrates. However, if such modifications are made at constant inlet velocities, conversion and temperature profiles are considerably affected. Similar effects are observed when catalyst layer thicknesses are increased. (C) 2003 Elsevier Ltd. All rights reserved.
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parametric sensitivity in Catalytic Plate Reactors with first order endothermic exothermic reactions
Chemical Engineering Journal, 2002Co-Authors: M Zanfir, Asterios GavriilidisAbstract:A Catalytic Plate Reactor (CPR) consisting of closely spaced Catalytically coated Plates, where endothermic and exothermic reactions take place in alternate channels is studied. The influence of several design parameters on its thermal behaviour and performance is investigated by parametric sensitivity analysis (PSA) using a dimensionless model for an infinite length Reactor. Reactor temperature sensitivity with respect to ratio of inlet velocities, inlet temperature, ratio of pre-exponential factors, difference in activation energies, and heat effect numbers is investigated. It is demonstrated that different catalysts can show similar thermal behaviour and performance but exhibit different sensitivity behaviour. The latter is mainly influenced by the activation energies and the inlet temperature. It was found that the most sensitive behaviour is obtained during cold spot rather than hot spot or isothermal operation. A criterion is proposed in order to appreciate the flexibility of design and operating parameters, so that the Reactor temperature is kept within an acceptable operating range.
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modelling of a Catalytic Plate Reactor for dehydrogenation combustion coupling
Chemical Engineering Science, 2001Co-Authors: M Zanfir, Asterios GavriilidisAbstract:Coupling an endothermic with an exothermic reaction in a Plate heat exchanger having both sides of the Plates covered with appropriate catalysts results in a compact and intensified unit known as Catalytic Plate Reactor (CPR). In this work, Catalytic ethane dehydrogenation taking place in a CPR having as heat source Catalytic methane combustion is modelled. Reactor behaviour is studied utilising a two-dimensional model and the influence of parameters such as catalyst loading, flowrates and wall thermal conductivity is investigated. It is shown that the ratio of catalyst loadings for the two reactions is a key variable, which must be carefully adjusted in order to avoid hot spots or insufficient reactant conversion. It is further demonstrated that hot and cold spots develop when heat generated and heat consumed are not balanced locally. Utilisation of a metallic wall makes possible efficient heat transfer between endothermic/exothermic reaction locations for small temperature differences. However, lower Plate thermal conductivity can lead not only to significant radial but also to axial temperature gradients.
Arsalan M Ashraf - One of the best experts on this subject based on the ideXlab platform.
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experimental insights into the coupling of methane combustion and steam reforming in a Catalytic Plate Reactor in transient mode
Industrial & Engineering Chemistry Research, 2021Co-Authors: Arsalan M Ashraf, Stefano Tacchino, Nageswara Rao Peela, Giuliana Ercolino, Kirandeep K Gill, Dionisios G Vlachos, Stefania SpecchiaAbstract:The microstructured Reactor concept is very promising technology to develop a compact reformer for distributed hydrogen generation. In this work, a Catalytic Plate Reactor (CPR) is developed and in...
Jan Kopyscinski - One of the best experts on this subject based on the ideXlab platform.
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improved kinetic data acquisition using an optically accessible Catalytic Plate Reactor with spatially resolved measurement techniques case of study co2 methanation
Catalysts, 2018Co-Authors: Jose Hernandez A Lalinde, Kevin Kofler, Xuejie Huang, Jan KopyscinskiAbstract:Modelling and optimization of chemical Reactors require a good understanding of the reactions mechanism with the corresponding kinetic description. Therefore, high quality kinetic data are needed, which can be challenging to obtain, especially for fast and highly exothermic reactions such as the CO2 methanation. Traditionally, kinetic studies rely on measuring the exit gas composition (1 data point per species and experiment) using differential Reactors with diluted catalyst beds and reactants to avoid temperature change. Therefore, an optically accessible Catalytic channel Reactor was designed, which allowed for the chance to gather spatially-resolved information on axial gas composition and catalyst surface temperature, specifically by means of a movable sampling capillary and shortwave infrared-thermography (SWIR), respectively. A catalyst coated Plate was placed at the bottom of the channel, while a set of two quartz glass Plates covers the top. In the current study 35 data points per gas species were collect for 1 experiment conducted under laminar flow conditions at 425 °C. Catalyst surface temperature determined via a SWIR camera was not influenced by polyatomic molecules partaking in the reaction and thus did not falsify the kinetic data. The catalyst mass distribution along the Reactor axis was determined, enabling the development of a correct Reactor model for kinetic parameter estimation and model discrimination.
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applying spatially resolved concentration and temperature measurements in a Catalytic Plate Reactor for the kinetic study of co methanation
Journal of Catalysis, 2010Co-Authors: Jan Kopyscinski, Tilman J Schildhauer, Frederic Vogel, Serge M A Biollaz, Alexander WokaunAbstract:In this work, the successful application of spatially resolved measurements in an optically accessible Catalytic Plate Reactor was demonstrated, which allows the detailed investigation of the reaction kinetics of the exothermic CO methanation reaction with high initial CO partial pressure. By means of a movable sampling capillary, the axial gas species concentration profiles over the catalyst Plate were measured, and the catalyst surface temperature was determined simultaneously along the Reactor through a quartz glass window by means of infrared thermography. A one-dimensional model of the Catalytic Plate Reactor and a Bayesian approach were applied to estimate the kinetic model parameters of the proposed Langmuir–Hinshelwood rate expressions by comparing simulated and measured gas concentration profiles. The validity of using a computationally efficient one-dimensional model was proven by solving a two-dimensional model using the kinetic parameters determined with the one-dimensional model and by comparing the two results.
Vinod M Janardhanan - One of the best experts on this subject based on the ideXlab platform.
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modeling process intensified Catalytic Plate Reactor for synthesis gas production
Chemical Engineering Science, 2014Co-Authors: Prashil Lakhete, Vinod M JanardhananAbstract:This paper presents numerical study of co- and counter-flow arrangements for Catalytic Plate Reactors (CPR). CH4 steam reforming coupled with CH4 oxidation is simulated using detailed surface reaction mechanisms. Effect of inlet velocities to the reforming channel, oxidation channel, and material properties of the Plate on the resulting Plate temperature and CH4 conversions is studied. The simulation results agree very well with an industrial scale reformer unit and calculations are further carried out to evaluate the number of CPRs and stacks required to replace and industrial unit.
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numerical study of on board fuel reforming in a Catalytic Plate Reactor for solid oxide fuel cells
Chemical Engineering Science, 2011Co-Authors: Vinod M Janardhanan, Srinivas Appari, S Jayanti, Olaf DeutschmannAbstract:A pseudo-transient numerical model is used for the simulation of a multi-functional Catalytic Plate Reactor (CPR). The work mainly addresses the problems associated with on-board reforming for solid-oxide fuel cells. Heat management is achieved by indirectly coupling partial oxidation with reforming. Water management is achieved by partially recycling the anode stream from a solid-oxide fuel cell. The model uses detailed heterogeneous chemistry for reforming and oxidation reactions occurring on the catalyst beds.
M Zanfir - One of the best experts on this subject based on the ideXlab platform.
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Catalytic combustion assisted methane steam reforming in a Catalytic Plate Reactor
Chemical Engineering Science, 2003Co-Authors: M Zanfir, Asterios GavriilidisAbstract:A theoretical study of methane steam reforming coupled with methane Catalytic combustion in a Catalytic Plate Reactor (CPR) based on a two-dimensional model is presented. Plates with coated catalyst layers of order of micrometers at distances of order of millimetres offer a high degree of compactness and minimise heat and mass transport resistances. Choosing similar operating conditions in terms of inlet composition and temperature as in industrial reformer allows a direct comparison of CPRs with the latter. It is shown that short distance between heat source and heat sink increases the efficiency of heat exchange. Transverse temperature gradients do not exceed 0.5 K across the wall and 40 K across the gas-phase, in contrast to 250 K difference in temperature of outside wall and mean gas phase temperature inside the tube usually observed in conventional reformers. The effectiveness factors for the reforming chemical reactions are about one order of magnitude higher than in conventional processes. Minimisation of heat and mass transfer resistances results in reduction of Reactor volume and catalyst weight by two orders of magnitude as compared to industrial reformer. Alteration of distance between Plates in the range 1-4 mm does not result in significant difference in Reactor performance, if made at constant inlet flowrates. However, if such modifications are made at constant inlet velocities, conversion and temperature profiles are considerably affected. Similar effects are observed when catalyst layer thicknesses are increased. (C) 2003 Elsevier Ltd. All rights reserved.
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parametric sensitivity in Catalytic Plate Reactors with first order endothermic exothermic reactions
Chemical Engineering Journal, 2002Co-Authors: M Zanfir, Asterios GavriilidisAbstract:A Catalytic Plate Reactor (CPR) consisting of closely spaced Catalytically coated Plates, where endothermic and exothermic reactions take place in alternate channels is studied. The influence of several design parameters on its thermal behaviour and performance is investigated by parametric sensitivity analysis (PSA) using a dimensionless model for an infinite length Reactor. Reactor temperature sensitivity with respect to ratio of inlet velocities, inlet temperature, ratio of pre-exponential factors, difference in activation energies, and heat effect numbers is investigated. It is demonstrated that different catalysts can show similar thermal behaviour and performance but exhibit different sensitivity behaviour. The latter is mainly influenced by the activation energies and the inlet temperature. It was found that the most sensitive behaviour is obtained during cold spot rather than hot spot or isothermal operation. A criterion is proposed in order to appreciate the flexibility of design and operating parameters, so that the Reactor temperature is kept within an acceptable operating range.
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modelling of a Catalytic Plate Reactor for dehydrogenation combustion coupling
Chemical Engineering Science, 2001Co-Authors: M Zanfir, Asterios GavriilidisAbstract:Coupling an endothermic with an exothermic reaction in a Plate heat exchanger having both sides of the Plates covered with appropriate catalysts results in a compact and intensified unit known as Catalytic Plate Reactor (CPR). In this work, Catalytic ethane dehydrogenation taking place in a CPR having as heat source Catalytic methane combustion is modelled. Reactor behaviour is studied utilising a two-dimensional model and the influence of parameters such as catalyst loading, flowrates and wall thermal conductivity is investigated. It is shown that the ratio of catalyst loadings for the two reactions is a key variable, which must be carefully adjusted in order to avoid hot spots or insufficient reactant conversion. It is further demonstrated that hot and cold spots develop when heat generated and heat consumed are not balanced locally. Utilisation of a metallic wall makes possible efficient heat transfer between endothermic/exothermic reaction locations for small temperature differences. However, lower Plate thermal conductivity can lead not only to significant radial but also to axial temperature gradients.