CatKin (Catalytic Kinetics)
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Purpose of the program |
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CatKin (Catalytic Kinetics) is an application for deriving expressions of
overall rate equations and parameter estimation in complex heterogeneous catalytic reactions.
It is a powerful tool that is based on up-to-date numerical methods and Graph theory.
The main features of CatKin are:
- friendly user interface;
- wide range of kinetic mechanisms;
- automated procedure for simplifying kinetic models;
- comprehensive statistical treatment of solution results;
- analysis of multiplicity and stability of the solutions;
- up-to-date numerical methods.
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Chemical kinetics |
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CatKin works with heterogeneous chemical kinetics.
The "kinetics" term contains both chemical equations and kinetics constants.
Each constant has its own name and units, e.g., activation energy, kJ/mol.
Three groups of kinetic models are available:
- linear models;
- Hougen - Watson models;
- nonstandard (user provided) models.
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Linear models |
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Linear models are the models where the sum of coefficients at active sites and surface
intermediates is equal to or less than 1.
While inputting, the original automated procedure is used to derive reaction rate equations.
Rate constants of fast reactions are excluded; for fast reversible reactions only equilibrium
constants are taken into account. It allows reducing total number of unknown constants and
simplifying estimation of the best values.
The procedure is based on the Graph theory and can be applied if stoichiometric coefficients
for intermediates are equal to one or zero. According to this limitation, it covers all the
mechanisms of Langmuir-Hinshelwood (Hougen-Watson) and Rideal-Ele. Moreover, it allows
working with multi-path reactions.
CatKin works with heterogeneous chemical kinetics.
The "kinetics" term contains both chemical equations and kinetics constants.
Each constant has its own name and units, e.g., activation energy, kJ/mol.
Three groups of kinetic models are available:
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Hougen-Watson models |
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Approximately 40 different, ready-to-use, Hougen-Watson models were implemented in
CatKin. These models describe reactions of molecularly or atomically adsorbed species at
various limiting steps.
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Nonstandard (user provided) models |
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User has a useful opportunity to implement his own, nonstandard models in CatKin.
This ensures kinetic analysis of reactions lying outside of two pre-defined model groups.
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Models |
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CatKin deals with mathematical models of bench scale fixed-bed reactors.
Two kinds of models are used:
- integral reactor;
- differential reactor.
The model of the integral plug flow reactor and integral pulse flow reactors are
represented by ordinary differential equations.
Model of a reactor with inner or outer recycle are algebraic ones.
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Experimental data |
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Conditions of experiments are referred to as factors. They can be inlet flow concentrations,
temperature and total pressure. Results of experiments are referred to as responses. Responses are
concentrations of components in outlet flow.
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Simulation |
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Up-to-date numerical methods are utilized in solving stiff and non-stiff ordinary
differential and algebraic equations.
Results of simulation can be presented as plots and tables.
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Estimation |
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With CatKin you can estimate the best parameter values for nonlinear models.
The comprehensive statistical treatment, analysis of multiplicity and stability of the solutions
are available.
It is known that the problem has to be well-posed, i.e., the existence, uniqueness and stability
of estimates of parameters are assumed. Automated methods of stability analysis and multiplicity
checking are implemented.
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