Modeling and Simulation of a Packed-bed Reactor for Carrying out the Water-Gas Shift Reaction

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Yaidelin A. Manrique ◽  
Carlos V. Miguel ◽  
Diogo Mendes ◽  
Adelio Mendes ◽  
Luis M. Madeira
Keyword(s):  
Fixed Bed ◽  
Packed Bed ◽  
Packed Bed Reactor ◽  
Fixed Bed Reactor ◽  
Water Gas Shift ◽  
Small Scale ◽  
Heterogeneous Model ◽  
Co Conversion ◽  
Reactor Operating ◽  
Water Gas

Abstract In this work the water-gas shift (WGS) process was addressed, with particular emphasis in the development of phenomenological models that can reproduce experimental results in a WGS reactor operating at low temperatures. It was simulated the conversion obtained in a fixed-bed reactor (PBR) packed with a Cu-based catalyst making use of a composed kinetic equation in which the Langmuir-Hinshelwood rate model was used for the lowest temperature range (up to 215 ºC), while for temperatures in the range 215 – 300 ºC a redox model was employed. Several packed-bed reactor models were then proposed, all of them without any fitting parameters. After comparing the simulations against experimental CO conversion data for different temperatures and space time values, it was concluded that the heterogeneous model comprising axial dispersion and mass transfer resistances shows the best fitting. This model revealed also good adherence to other experiments employing different feed compositions (CO and H2O contents); it predicts also the overall trend of increasing CO conversion with the total pressure. This modeling work is particularly important for small scale applications related with hydrogen production/purification for fuel cells.

CO2 Sorption by Hydrotalcite-Like Compounds in Dry and Wet Conditions

2015 ◽  
Vol 13 (3) ◽  
pp. 335-349 ◽  
Author(s):  
Katia Gallucci ◽  
Francesca Micheli ◽  
Alessandro Poliandri ◽  
Leucio Rossi ◽  
Pier Ugo Foscolo
Keyword(s):  
Thermal Treatment ◽  
Fixed Bed ◽  
Flow Distribution ◽  
Experimental System ◽  
Xrd Analysis ◽  
Fixed Bed Reactor ◽  
Water Gas Shift ◽  
Distribution Model ◽  
Time Flow ◽  
Water Gas

Abstract A pre-combustion removal option, coupling water–gas shift and CO2 capture is the well-known sorption-enhanced water–gas shift (SEWGS): the removal of CO2 produced by WGS reaction, shifting the thermodynamic equilibrium, enhances H2 production. Among the different CO2 sorbents, hydrotalcite-like compounds work at the required intermediate temperature (T = 200–400°C). Using low supersaturation method, three different sorbents were synthesized. Sieved fractions were impregnated with 20%w/w K2CO3 and then dried and subjected to thermal treatment. Sample characterization was performed by means of FT-IR spectroscopy, XRD analysis and TG-DTA analysis. Sample analysis was carried out after synthesis, thermal treatment (calcination) and after fixed bed reactor capture tests. Sorption and desorption tests were performed in a fixed bed microreactor, under cyclic conditions, at temperature level of T = 350°C and P = 5 bar in dry and wet condition. The amount of CO2 captured by the sorbent in each test was quantified by means of a first order with dead time flow distribution model applied to the experimental system. Sorption capacity of sorbents in dry conditions increases of 30% with respect to previous atmospheric pressure results obtained in fluidized bed. These sorbents seem to be good candidates to be used as a bi-functional sorbent-catalyst for SEWGS.

Steady State Model for Heat Transfer in a Packed Bed Reactor of Elliptic Cylindrical Shape

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Laércio G. Oliveira ◽  
Ramdayal Swarnakar ◽  
Antonio G. B. de Lima
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Fixed Bed ◽  
Packed Bed ◽  
Numerical Results ◽  
Packed Bed Reactor ◽  
Fixed Bed Reactor ◽  
Dimensionless Temperature ◽  
Cylindrical Shape ◽  
Temperature Profiles

The fixed-bed reactors of circular cylindrical geometry with heated or cooled walls are frequently used to carry out heterogeneous reactions of solid-gas type in engineering applications. The design of a fixed bed reactor requires an extensive knowledge of heat transfer characteristics within the packed bed. In this sense, this work presents a three-dimensional mathematical model to predict the heat transfer inside a fixed bed elliptical cylinder heat exchanger. The model considers uniform velocity and temperature profiles of the fluid phase at the entrance of the reactor, and constant thermo-physical properties. The surface of the equipment convective boundary condition is assumed to be constant. The energy equation, written in the elliptical cylindrical coordinates, was discretized using a finite-volume method considering a fully implicit formulation, and WUDS interpolation scheme. Numerical results of the dimensionless temperature profiles inside the packed bed reactor at a steady state are presented and temperature distribution is interpreted. To validate the model, numerical results obtained for the circular cylinder are compared with analytical results from literature and a good agreement was obtained.

scholarly journals Kinetics and Reactor Design Aspects of Selective Methanation of CO over a Ru/γ-Al2O3 Catalyst in CO2/H2 Rich Gases

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 469 ◽  
Author(s):  
Panagiota Garbis ◽  
Christoph Kern ◽  
Andreas Jess
Keyword(s):  
Polymer Electrolyte Membrane ◽  
Fixed Bed ◽  
Kinetic Equations ◽  
Fixed Bed Reactor ◽  
Water Gas Shift ◽  
Co2 Methanation ◽  
Co Methanation ◽  
Electrolyte Membrane ◽  
Selective Co Methanation ◽  
Water Gas

Polymer electrolyte membrane fuel cells (PEMFCs) for household applications utilize H2 produced from natural gas via steam reforming followed by a water gas shift (WGS) unit. The H2-rich gas contains CO2 and small amounts of CO, which is a poison for PEMFCs. Today, CO is mostly converted by addition of O2 and preferential oxidation, but H2 is then also partly oxidized. An alternative is selective CO methanation, studied in this work. CO2 methanation is then a highly unwanted reaction, consuming additional H2. The kinetics of CO methanation in CO2/H2 rich gases were studied with a home-made Ru catalyst in a fixed bed reactor at 1 bar and 160–240 °C. Both CO and CO2 methanation can be well described by a Langmuir Hinshelwood approach. The rate of CO2 methanation is slow compared to CO. CO2 is directly converted to methane, i.e., the indirect route via reverse water gas shift (WGS) and subsequent CO methanation could be excluded by the experimental data and in combination with kinetic considerations. Pore diffusion may affect the CO conversion (>200 °C). The kinetic equations were applied to model an adiabatic fixed bed methanation reactor of a fuel cell appliance.

Hydrogen Production via Low Temperature Water Gas Shift Reaction: Kinetic Study, Mathematical Modeling, Simulation and Optimization of Catalytic Fixed Bed Reactor using gPROMS

2017 ◽  
Vol 12 (3) ◽  
Author(s):  
Davood Mohammady Maklavany ◽  
Ahmad Shariati ◽  
Mohammad Reza Khosravi-Nikou ◽  
Behrooz Roozbehani
Keyword(s):  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Water Gas Shift ◽  
Optimal Controls ◽  
Water Gas Shift Reaction ◽  
Hydrogen Formation ◽  
Simulation And Optimization ◽  
Modeling Simulation ◽  
Shift Reaction ◽  
Water Gas

Abstract The kinetics study, modeling, simulation and optimization of water gas shift reaction were performed in a catalytic fixed bed reactor. The renowned empirical power law rate model was used as rate equation and fitted to experimental data to estimate the kinetics parameters using gPROMS. A good fit between predicted and experimental CO conversion data was obtained. The validity of the kinetic model was then checked by simulation of plug flow reactor which shows a good agreement between experimental and predicted values of the reaction rate. Subsequently, considering axial dispersion, a homogeneous model was developed for simulation of the water-gas shift reactor. The simulation results were also validated by checking the pressure drop of the reactor as well as the mass concentration at equilibrium. Finally, a multi-objective optimization was conducted for water-gas shift reaction in order to maximize hydrogen formation and carbon monoxide conversion, whereas the reactor volume to be minimized. Implementation of optimal controls leads to increase in hydrogen formation at reactor outlet up to 25.55 %.

Catalytic wet peroxidation of phenol in a fixed bed reactor

2007 ◽  
Vol 55 (12) ◽  
pp. 75-81 ◽  
Author(s):  
F. Martínez ◽  
M.I. Pariente ◽  
J.A. Melero ◽  
J.A. Botas ◽  
E. Gómez
Keyword(s):  
Phenol Degradation ◽  
Fixed Bed ◽  
Methyl Cellulose ◽  
Packed Bed ◽  
Packed Bed Reactor ◽  
Fixed Bed Reactor ◽  
Continuous Treatment ◽  
Catalyst Stability ◽  
Solid Catalyst ◽  
Relevant Role

Iron-containing mesostructured materials (Fe-SBA-15) are suitable for continuous treatment of phenolic aqueous solutions by means of catalytic wet peroxide oxidation (CWPO) in a packed-bed reactor. These materials were successfully extruded, crushed and sieved with a particle size ranging from 1 to 1.6 mm using mineral clay and methyl cellulose as binders. Non-significant changes have been found in the textural and structural properties of the extruded material in comparison to the parent powder Fe-SBA-15 material. Activity of extruded catalyst in terms of phenol degradation and TOC reduction has been monitored in a continuous mode. The increase of residence time enhances significantly the TOC degradation. The catalyst stability, taking into account the loss of iron species from the catalyst into the aqueous solution, has also been examined. The catalytic results of Fe-SBA-15 material in comparison to a homogeneous catalytic test prove the relevant role of the solid catalyst in the oxidation process.

Sign in / Sign up

Export Citation Format

Share Document