Conversion of Synthesis Gas into Light Hydrocarbons. Modelling of the Catalytic Reaction Network

2004 ◽  
Vol 2 (1) ◽  
Author(s):  
Louis Hagey ◽  
Hugo Ignacio de Lasa
Keyword(s):  
Kinetic Model ◽  
Kinetic Parameters ◽  
Gas Phase ◽  
Statistical Methods ◽  
Synthesis Gas ◽  
Catalytic Reaction ◽  
Reaction Network ◽  
Light Hydrocarbons ◽  
Model Based

This study considers a bi-functional catalyst for the conversion of synthesis gas into valuable light hydrocarbons. Catalysts are tested in a well-mixed Berty reactor. The effects of phosphorous additions on the overall catalyst performance including C5+ fractions and hydrocarbon yields are evaluated. The data obtained is very useful for establishing the validity of a kinetic model based on the gas phase observable species and to determine the various kinetic parameters of this model using statistical methods.

Kinetic modelling of the photocatalytic inactivation of bacteria

2010 ◽  
Vol 61 (6) ◽  
pp. 1547-1553 ◽  
Author(s):  
Javier Marugán ◽  
Rafael van Grieken ◽  
Alberto E. Cassano ◽  
Orlando M. Alfano
Keyword(s):  
Kinetic Model ◽  
Kinetic Parameters ◽  
Catalyst Concentration ◽  
Kinetic Modelling ◽  
Kinetic Constant ◽  
Water Disinfection ◽  
Radiation Absorption ◽  
Simple Modification ◽  
Model Based ◽  
Photocatalytic Inactivation

This work analyzes the kinetic modelling of the photocatalytic inactivation of E. coli in water using different types of kinetic models; from an empirical equation to an intrinsic kinetic model including explicit radiation absorption effects. Simple empirical equations lead to lower fitting errors, but require a total of 12 parameters to reproduce the results of four inactivation curves when the catalyst concentration was increased. Moreover, these parameters have no physical meaning and cannot be extrapolated to different experimental conditions. The use of a pseudo-mechanistic model based on a simplified reaction mechanism reduces the number of required kinetic parameters to 6, being the kinetic constant the only parameter that depends on the catalyst concentration. Finally, a simple modification of a kinetic model based on the intrinsic mechanism of photocatalytic reactions including explicit radiation absorption effects achieved the fitting of all the experiments with only three parameters. The main advantage of this approach is that the kinetic parameters estimated for the model become independent of the irradiation form, as well as the reactor size and its geometrical configuration, providing the necessary information for scaling-up and design of commercial-scale photoreactors for water disinfection.

The catalytic kinetics and cfd simulation of multi-stage combined removal of acrylonitrile tail gas

2021 ◽  
pp. 115-125
Author(s):  
Zhao Du ◽  
◽  
Qian Liu ◽  
Yuxuan Yang ◽  
◽  
...  
Keyword(s):  
Mathematical Model ◽  
Kinetic Model ◽  
Catalytic Reaction ◽  
Cfd Simulation ◽  
Reaction Network ◽  
External Diffusion ◽  
Quantitative Calculation ◽  
Dynamic Factors ◽  
Multi Stage ◽  
Catalytic Kinetics

There is no kinetic data and rate equation that can be used directly for catalytic combustion of acrylonitrile tail gas, which leads to the multi-stage combined catalytic kinetic model of acrylonitrile tail gas collaborative removal. In the actual application process, affected by the internal and external diffusion, this paper proposes the multi-stage combined catalytic kinetic research and CFD simulation analysis of acrylonitrile tail gas collaborative removal. Based on the judgment of multi-stage combined catalytic reaction rules of acrylonitrile tail gas collaborative removal, the multi-stage combined catalytic reaction network of acrylonitrile tail gas collaborative removal is solved by matrix transformation. The possible reaction path in the multi-stage combined catalytic reaction network of acrylonitrile tail gas collaborative removal is solved. For quantitative calculation of product distribution, each step of reaction parameters and dynamic factors are required. According to the mechanism of positive carbon ion reaction, materials were used Studio software and genetic algorithm are used to calculate the dynamic factors and determine the dynamic parameters; the grid automatic generator AutoGrid5 embedded in the Fine/TurboTM software package is used to generate the CFD simulation network, and the iterative algorithm is used to calculate the limit value of the CFD simulation; the S-A model in the CFD simulation platform is used to get the modified value of the dynamic mathematical model, and the dynamic factors and parameters are brought into it to establish the CA mathematical model of multi-stage combined catalytic kinetics for the CO removal of olefine and nitrile tail gas. The experimental results show that, under the same experimental device and parameters, the internal and external diffusion effects of the multi-stage combined catalytic kinetic model of acrylonitrile tail gas collaborative removal are detected. The multi-stage combined catalytic kinetic model of acrylonitrile tail gas collaborative removal in this study uses 10-20 mesh catalyst, and the retention time of acrylonitrile tail gas is less than 4.62 s, the internal and external diffusion will not affect the acrylonitrile tail gas collaborative removal The practical application of the kinetic model for the removal of multi-stage combined catalysis.

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

scholarly journals Variability in Estimated Modelled Insulin Secretion

2021 ◽  
pp. 193229682199112
Author(s):  
Jennifer J. Ormsbee ◽  
Hannah J. Burden ◽  
Jennifer L. Knopp ◽  
J. Geoffrey Chase ◽  
Rinki Murphy ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Kinetic Parameters ◽  
Pancreatic Beta Cells ◽  
Compartment Model ◽  
Interquartile Range ◽  
Cumulative Distribution ◽  
Model Framework ◽  
Intravenous Glucose ◽  
C Peptide ◽  
Model Based

Background: The ability to measure insulin secretion from pancreatic beta cells and monitor glucose-insulin physiology is vital to current health needs. C-peptide has been used successfully as a surrogate for plasma insulin concentration. Quantifying the expected variability of modelled insulin secretion will improve confidence in model estimates. Methods: Forty-three healthy adult males of Māori or Pacific peoples ancestry living in New Zealand participated in an frequently sampled, intravenous glucose tolerance test (FS-IVGTT) with an average age of 29 years and a BMI of 33 kg/m2. A 2-compartment model framework and standardized kinetic parameters were used to estimate endogenous pancreatic insulin secretion from plasma C-peptide measurements. Monte Carlo analysis (N = 10 000) was then used to independently vary parameters within ±2 standard deviations of the mean of each variable and the 5th and 95th percentiles determined the bounds of the expected range of insulin secretion. Cumulative distribution functions (CDFs) were calculated for each subject for area under the curve (AUC) total, AUC Phase 1, and AUC Phase 2. Normalizing each AUC by the participant’s median value over all N = 10 000 iterations quantifies the expected model-based variability in AUC. Results: Larger variation is found in subjects with a BMI > 30 kg/m2, where the interquartile range is 34.3% compared to subjects with a BMI ≤ 30 kg/m2 where the interquartile range is 24.7%. Conclusions: Use of C-peptide measurements using a 2-compartment model and standardized kinetic parameters, one can expect ~±15% variation in modelled insulin secretion estimates. The variation should be considered when applying this insulin secretion estimation method to clinical diagnostic thresholds and interpretation of model-based analyses such as insulin sensitivity.

Model-based analysis of coupled equilibrium-kinetic processes: indirect kinetic studies of thermodynamic parameters using the dynamic data

The Analyst ◽  
2015 ◽  
Vol 140 (9) ◽  
pp. 3121-3135
Author(s):  
Fereshteh Emami ◽  
Marcel Maeder ◽  
Hamid Abdollahi
Keyword(s):  
Kinetic Model ◽  
Thermodynamic Parameters ◽  
Kinetic Models ◽  
Kinetic Studies ◽  
Dynamic Data ◽  
Model Based ◽  
Kinetic Processes ◽  
Model Based Analysis

Schematic of intertwined equilibrium-kinetic model at time = 0,1,2…T when both equilibrium and kinetic models are solved explicitly.

scholarly journals The kinetics of the hydrogen chloride oxidation

2013 ◽  
Vol 78 (12) ◽  
pp. 2115-2130 ◽  
Author(s):  
Martinez Gonzalez ◽  
Tanja Vidakovic-Koch ◽  
Rafael Kuwertz ◽  
Ulrich Kunz ◽  
Thomas Turek ◽  
...  
Keyword(s):  
Kinetic Parameters ◽  
Gas Phase ◽  
Hydrogen Chloride ◽  
Reaction Order ◽  
Membrane Electrode ◽  
Polarization Data ◽  
Rate Determining Step ◽  
Electrode Assemblies ◽  
Apparent Kinetic Parameters ◽  
Kinetics Of

Hydrogen chloride (HCl) oxidation has been investigated on technical membrane electrode assemblies in a cyclone flow cell. Influence of Nafion loading, temperature and hydrogen chloride mole fraction in the gas phase has been studied. The apparent kinetic parameters like reaction order with respect to HCl, Tafel slope and activation energy have been determined from polarization data. The apparent kinetic parameters suggest that the recombination of adsorbed Cl intermediate is the rate determining step.

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