Prediction of the fixed-bed reactor behaviour using dispersion and plug-flow models with different kinetics for immobilised enzyme

2003 ◽  
Vol 92 (1-3) ◽  
pp. 123-129 ◽  
Author(s):  
Carlos R Carrara ◽  
Enrique J Mammarella ◽  
Amelia C Rubiolo
Keyword(s):  
Plug Flow ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Flow Models

Hydrogen Production from Ethanol Steam Reforming: Fixed Bed Reactor Design

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Pablo Giunta ◽  
Norma Amadeo ◽  
Miguel Laborde
Keyword(s):  
Steam Reforming ◽  
Flow Model ◽  
Multicomponent Mixture ◽  
Plug Flow ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Ethanol Steam Reforming ◽  
Heterogeneous Model ◽  
Ethanol Steam ◽  
Hydrogen Stream

The aim of this work is to design an ethanol steam reformer to produce a hydrogen stream capable of feeding a 60 kW PEM fuel cell applying the plug flow model, considering the presence of the catalyst bed (heterogeneous model). The Dusty-Gas Model is employed for the catalyst, since it better predicts the fluxes of a multicomponent mixture. Moreover, this model has shown to be computationally more robust than the Fickian Model. A power law-type kinetics was used. Results showed that it is possible to carry out the ethanol steam reforming in a compact device (1.66 x 10 -5 to 5.27 x 10 -5 m3). It was also observed that this process is determined by heat transfer.

Optimal Design, Modeling and Simulation of an Ethanol Steam Reforming Reactor

2009 ◽  
Vol 7 (1) ◽  
Author(s):  
Luis E Arteaga ◽  
Luis M Peralta ◽  
Yannay Casas ◽  
Daikenel Castro
Keyword(s):  
Hydrogen Production ◽  
Modeling And Simulation ◽  
Design Patterns ◽  
Plug Flow ◽  
Fixed Bed ◽  
Cell System ◽  
Fixed Bed Reactor ◽  
Effect Of Temperature ◽  
Ethanol Conversion ◽  
Renewable Hydrogen

The optimum design, modeling and simulation of a fixed bed multi-tube reformer for the renewable hydrogen production are carried out in the present paper. The analogies between plug flow model and a fixed bed reactor are used as design patterns. The steam reformer is designed to produce enough hydrogen to feed a 200kW fuel cell system (>2.19molH/s) and considering 85% of fuel utilization in the cell electrodes. The reactor prototype is optimized and then analyzed using a multiphysics and axisymmetric model, implemented on FEMLABM(R) where the differential mass balance by convection-diffusion and the energy balance for convection-conduction are solved. The temperature profile is controlled to maximize hydrogen production. The catalyst bed internal profiles and the effect of temperature on ethanol conversion and carbon monoxide production are discussed as well.

Comparison between dispersion and plug-flow models for fixed-bed enzyme reactors

AIChE Journal ◽  
1992 ◽  
Vol 38 (9) ◽  
pp. 1477-1480 ◽  
Author(s):  
Robert Lortie ◽  
Dominique Pelletier
Keyword(s):  
Plug Flow ◽  
Fixed Bed ◽  
Flow Models ◽  
Enzyme Reactors

Treatment of Strong Wastewaters by Fixed Bed Anaerobic Reactors with Organic Support

1994 ◽  
Vol 29 (9) ◽  
pp. 257-263 ◽  
Author(s):  
A. Guitonas ◽  
G. Paschalidis ◽  
A. Zouboulis
Keyword(s):  
Immobilized Cells ◽  
Research Effort ◽  
Plug Flow ◽  
Fixed Bed ◽  
Anaerobic Treatment ◽  
Treatment System ◽  
Fixed Bed Reactor ◽  
Flow Mode ◽  
Treatment Efficiency ◽  
Low Strength

In this experimental study the treatment efficiency on a milk based synthetic organic waste is examined of a fixed bed reactor with immobilized cells in organic support (straw). The aim of this research effort was to demonstrate an anaerobic treatment system which is flexible enough and can be used widely at small agroindustrial units as a low-energy-demanding treatment system. It can also be possibly used for the stabilization of the organic support, which can consequently be incorporated for the faster evolution of the composting phenomenon. A significant number of concentrations at the entrance of the fixed bed reactor, with a volume of V = 10.7 1, constructed from plexiglass and downflow fed, has been applied at different hydraulic retention times and at different temperatures (35°, 25°, 15°C). The examined reactor operates in plug-flow mode and the conclusions that were drawn from the experiments, with the above anaerobic treatment system are as follow. The treatment system can treat high and low strength effluents with considerable treatment efficiency. It can treat low strength effluents, with sufficient treatment efficiency, at medium and low temperatures, for anaerobic digestion standards. The time for adaption between different applied loadings at the inlet is quite short, which indicates the considerable flexibility and utility of the system.

scholarly journals Particle-Resolved Computational Fluid Dynamics as the Basis for Thermal Process Intensification of Fixed-Bed Reactors on Multiple Scales

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2913
Author(s):  
Nico Jurtz ◽  
Urvashi Srivastava ◽  
Alireza Attari Moghaddam ◽  
Matthias Kraume
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Heat Transport ◽  
Multiple Scales ◽  
Plug Flow ◽  
Fixed Bed ◽  
Process Intensification ◽  
Transport Parameters ◽  
Flow Models ◽  
Fixed Bed Reactors

Process intensification of catalytic fixed-bed reactors is of vital interest and can be conducted on different length scales, ranging from the molecular scale to the pellet scale to the plant scale. Particle-resolved computational fluid dynamics (CFD) is used to characterize different reactor designs regarding optimized heat transport characteristics on the pellet scale. Packings of cylinders, Raschig rings, four-hole cylinders, and spheres were investigated regarding their impact on bed morphology, fluid dynamics, and heat transport, whereby for the latter particle shape, the influence of macroscopic wall structures on the radial heat transport was also studied. Key performance indicators such as the global heat transfer coefficient and the specific pressure drop were evaluated to compare the thermal performance of the different designs. For plant-scale intensification, effective transport parameters that are needed for simplified pseudo-homogeneous two-dimensional plug flow models were determined from the CFD results, and the accuracy of the simplified modeling approach was judged.

scholarly journals Solution and Parameter Identification of a Fixed-Bed Reactor Model for Catalytic CO2 Methanation Using Physics-Informed Neural Networks

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1304
Author(s):  
Son Ich Ngo ◽  
Young-Il Lim
Keyword(s):  
Neural Networks ◽  
Reaction Kinetics ◽  
Flow Reactor ◽  
Plug Flow ◽  
Fixed Bed ◽  
Effectiveness Factor ◽  
Fixed Bed Reactor ◽  
Reactor Model ◽  
Co2 Methanation ◽  
Chemical Reaction Kinetics

In this study, we develop physics-informed neural networks (PINNs) to solve an isothermal fixed-bed (IFB) model for catalytic CO2 methanation. The PINN includes a feed-forward artificial neural network (FF-ANN) and physics-informed constraints, such as governing equations, boundary conditions, and reaction kinetics. The most effective PINN structure consists of 5–7 hidden layers, 256 neurons per layer, and a hyperbolic tangent (tanh) activation function. The forward PINN model solves the plug-flow reactor model of the IFB, whereas the inverse PINN model reveals an unknown effectiveness factor involved in the reaction kinetics. The forward PINN shows excellent extrapolation performance with an accuracy of 88.1% when concentrations outside the training domain are predicted using only one-sixth of the entire domain. The inverse PINN model identifies an unknown effectiveness factor with an error of 0.3%, even for a small number of observation datasets (e.g., 20 sets). These results suggest that forward and inverse PINNs can be used in the solution and system identification of fixed-bed models with chemical reaction kinetics.

scholarly journals Axial Dispersion Plug Flow Model for Methanol Dehydration Reactor

2021 ◽  
Author(s):  
Masoud Habibi Zare ◽  
Mohammad Davar Mahlouji
Keyword(s):  
Flow Model ◽  
Plug Flow ◽  
Fixed Bed ◽  
Effectiveness Factor ◽  
Fixed Bed Reactor ◽  
Pore Network Model ◽  
One Dimensional ◽  
Catalyst Pellet ◽  
Transfer Equations ◽  
Mass And Heat Transfer

Abstract One-dimensional heterogeneous dispersed plug flow (DPF) model is employed to model an adiabatic fixed-bed reactor for the catalytic dehydration of methanol to dimethyl ether (DME). The mass and heat transfer equations are numerically solved for the reactor. The concentration of the reactant and products and also the temperature varies along the reactor, therefore the effectiveness factor would also change in the reactor. We used the effectiveness factor that was simulated according to the diffusion and reaction in the catalyst pellet as a pore network model. The predicted distribution for the effectiveness factor was utilized for the reactor simulation. The simulation results were compared to the experimental data and a satisfactory agreement was confirmed.

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