Accurate one-dimensional fixed-bed reactor model based on asymptotic analysis

AIChE Journal ◽  
1988 ◽  
Vol 34 (8) ◽  
pp. 1367-1372 ◽  
Author(s):  
M. Herskowitz ◽  
P. S. Hagan
Keyword(s):  
Asymptotic Analysis ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Reactor Model ◽  
One Dimensional ◽  
Model Based

scholarly journals Analysis and Model-Based Description of the Total Process of Periodic Deactivation and Regeneration of a VOx Catalyst for Selective Dehydrogenation of Propane

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1374
Author(s):  
Andreas Brune ◽  
Andreas Seidel-Morgenstern ◽  
Christof Hamel
Keyword(s):  
Catalyst Deactivation ◽  
Process Development ◽  
Coke Formation ◽  
Fixed Bed ◽  
Reaction Network ◽  
Fixed Bed Reactor ◽  
Side Reactions ◽  
Model Based ◽  
Total Process

This study intends to provide insights into various aspects related to the reaction kinetics of the VOx catalyzed propane dehydrogenation including main and side reactions and, in particular, catalyst deactivation and regeneration, which can be hardly found in combination in current literature. To kinetically describe the complex reaction network, a reduced model was fitted to lab scale experiments performed in a fixed bed reactor. Additionally, thermogravimetric analysis (TGA) was applied to investigate the coking behavior of the catalyst under defined conditions considering propane and propene as precursors for coke formation. Propene was identified to be the main coke precursor, which agrees with results of experiments using a segmented fixed bed reactor (FBR). A mechanistic multilayer-monolayer coke growth model was developed to mathematically describe the catalyst coking. Samples from long-term deactivation experiments in an FBR were used for regeneration experiments with oxygen to gasify the coke deposits in a TGA. A power law approach was able to describe the regeneration behavior well. Finally, the results of periodic experiments consisting of several deactivation and regeneration cycles verified the long-term stability of the catalyst and confirmed the validity of the derived and parametrized kinetic models for deactivation and regeneration, which will allow model-based process development and optimization.

Modeling and Optimization of MeOH to DME in Isothermal Fixed-bed Reactor

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Mohammad Farsi ◽  
Abdolhossein Jahanmiri ◽  
Reza Eslamloueyan
Keyword(s):  
Fixed Bed ◽  
Methanol Conversion ◽  
Fixed Bed Reactor ◽  
Methanol Dehydration ◽  
Algebraic Equations ◽  
Optimal Temperature ◽  
Heterogeneous Model ◽  
One Dimensional ◽  
Shell And Tube ◽  
Green Fuel

Dimethyl ether (DME) is a green fuel that commercially produced in an adiabatic fixed bed reactor by methanol dehydration. In the present work, a shell and tube fixed bed reactor is modeled and optimized for DME production. The reactor is modeled based on mass and energy conservation equations as well as auxiliary equations. In order to estimate the DME production and temperature profile along the reactor, a one dimensional heterogeneous model consist of a set of nonlinear differential and algebraic equations has been solved numerically. Also, The DME production in the isothermal reactor is maximized by adjusting the optimal temperature distribution along the reactor using genetic algorithm. Then, the performance of the proposed isothermal reactor is compared with industrial adiabatic fixed bed reactor. Results showed the higher DME production rate and methanol conversion in the optimized reactor.

Simulation Studies of Steam Reforming of Methane using Ni-Al2O3 Catalysts

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Giane Gonçalves Lenzi ◽  
Ervin Kaminski Lenzi ◽  
Cláudio Vilas Boas Fávero ◽  
Marcelo Kaminski Lenzi ◽  
Regina Maria Matos Jorge ◽  
...  
Keyword(s):  
Sol Gel ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Co2 Production ◽  
Simulation Studies ◽  
One Dimensional ◽  
Wgs Reaction ◽  
Different Characteristics ◽  
Water Gas ◽  
Al2o3 Catalyst

This paper reports the results of reforming methane into synthesis gas using industrial Ni-Al2O3 catalyst (75% NiO wt.) and Ni-Al2O3 produced by the sol gel method (8% Ni wt.). A mathematical investigation on the performance of a one-dimensional model of catalytic conventional fixed-bed reactor was developed and implemented for the process. The results indicated that the industrial catalyst favored the water gas shift (WGS) reaction increasing CO2 production. However in temperatures of 773 and 973 K the yield (H2/CH4,reacted) was more efficient for the sol-gel catalyst. This result is possibly due to the different characteristics as specific surface area and temperature reduction. The model validation for the adjustment parameters U and a1 was more efficient for temperature profiles (2% error) than for mole fraction (10% error).

Model-Based Experimental Analysis of a Fixed-Bed Reactor for Catalytic SO2Oxidation

2009 ◽  
Vol 48 (11) ◽  
pp. 5165-5176 ◽  
Author(s):  
J. C. Schöneberger ◽  
H. Arellano-Garcia ◽  
G. Wozny ◽  
S. Körkel ◽  
H. Thielert
Keyword(s):  
Experimental Analysis ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Model Based

Methane Dry Reforming over Ni-Co/Al2O3: Kinetic Modelling in a Catalytic Fixed-bed Reactor

2017 ◽  
Vol 15 (6) ◽  
Author(s):  
Yacine Benguerba ◽  
Mirella Virginie ◽  
Christine Dumas ◽  
Barbara Ernst
Keyword(s):  
Catalyst Deactivation ◽  
Kinetic Modelling ◽  
Fixed Bed ◽  
Dry Reforming ◽  
Fixed Bed Reactor ◽  
Coke Deposition ◽  
Dry Reforming Of Methane ◽  
Reactor Model ◽  
Reverse Water Gas Shift ◽  
Different Temperatures

Abstract The dry reforming of CH4 was investigated in a catalytic fixed-bed reactor to produce hydrogen at different temperatures over supported bimetallic Ni-Co catalyst. The reactor model for the dry reforming of methane used a set of kinetic models: The Zhang et al model for the dry reforming of methane (DRM); the Richardson-Paripatyadar model for the reverse water gas shift (RWGS); and the Snoeck et al kinetics for the coke-deposition and gasification reactions. The effect of temperatures on the performance of the reactor was studied. The amount of each species consumed or/and produced were calculated and compared with the experimental determined ones. It was showed that the set of kinetic model used in this work gave a good fit and accurately predict the experimental observed profiles from the fixed bed reactor. It was found that reaction-4 and reaction-5 could be neglected which could explain the fact that this catalyst coked rapidly comparatively with other catalyst. The use of large amount of Ni-Co will lead to carbon deposition and so to the catalyst deactivation.

A Trickle Fixed-Bed Recycle Reactor Model for the Fischer-Tropsch Synthesis

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Kyle M. Brunner ◽  
Joshua C. Duncan ◽  
Luke D. Harrison ◽  
Kyle E. Pratt ◽  
Robson P. S. Peguin ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Prandtl Number ◽  
Fixed Bed ◽  
Effective Diffusivity ◽  
Tropsch Synthesis ◽  
Fixed Bed Reactor ◽  
Maximum Temperature ◽  
Reactor Model ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis

A trickle fixed-bed reactor model for the Fischer-Tropsch synthesis applicable to both cobalt and iron catalysts which accounts for gas and liquid recycle is described. A selection of kinetic models for both iron and cobalt catalysts (4 each) is included in the reactor model and their effect on model predictions is compared. While the model is 1-D and reaction rates are determined for quasi-average radial bed temperatures, a correlation is used to account for radial thermal conductivity and radial convective heat transfer. Traditional pressure drop calculations for a packed column were modified with a correlation to account for trickle-flow conditions. In addition to describing the model in detail and showing validation results, this paper presents results of varying fundamental, theoretically-based parameters (i.e. effective diffusivity, Prandtl number, friction factor, etc.). For example, the model predicts that decreasing effective diffusivity from 7.1E-09 to 2.8E-09 m2/s results in a lower maximum temperature (518 K vs. 523 K) and a longer required bed length to achieve 60% conversion of CO (8.5 m vs. 5.7 m). Using molar averages of properties to calculate the Prandtl number for the gas phase (recommended by the authors) results in average bed temperatures up to 10 K higher and reactor lengths 17-45% shorter than assuming a Prandtl number of 0.7. Using the Tallmadge equation to estimate friction losses, as recommended by the authors, results in a pressure drop 40% smaller than using the Ergun equation. Validation of the model was accomplished by matching published full-scale plant data from the SASOL Arge reactors.

Simulation of coke and metal deposition in catalyst pellets using a non-steady state fixed bed reactor model

2006 ◽  
Vol 61 (22) ◽  
pp. 7463-7478 ◽  
Author(s):  
Bas M. Vogelaar ◽  
Rob J. Berger ◽  
Bas Bezemer ◽  
Jean-Paul Janssens ◽  
A. Dick van Langeveld ◽  
...  
Keyword(s):  
Steady State ◽  
Fixed Bed ◽  
Metal Deposition ◽  
Fixed Bed Reactor ◽  
Reactor Model ◽  
Catalyst Pellets

The Optimization of an Ammonia Synthesis Reactor Using Genetic Algorithm

2009 ◽  
Vol 6 (1) ◽  
Author(s):  
Mohammad Taghi Sadeghi ◽  
Azam Kavianiboroujeni
Keyword(s):  
Genetic Algorithm ◽  
Ammonia Synthesis ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Ammonia Production ◽  
Dimensional Model ◽  
Reactor Performance ◽  
One Dimensional ◽  
Operational Conditions ◽  
Quench Temperature

An industrial ammonia synthesis reactor was studied in order to optimize its operational conditions by means of increasing overall ammonia production. A heterogeneous, one-dimensional model and a two-dimensional rigorous model were utilized to evaluate the process behavior. The simulation results of the two models were compared with data from an industrial ammonia plant. The one-dimensional model was found to be adequate for optimization purposes. Applying the Genetic Algorithm (GA) as a powerful method for complex problems, the model was employed to optimize the reactor performance in varying its quench flows. The optimal temperature profile along the fixed bed reactor was studied by changing independent variables including the quench temperature and the quench flow rates. Optimization results show that the optimum quench temperature is about 615°K and that the optimum quench flows can enhance ammonia production rate by 3.3%.

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