Additional (External) Parameter
Contents
Project with Additional Parameter
Simulation: Predictions and Optimization
Introduction
Dependence on additional parameter is implemented in Kinetics Neo since version 3.0. In version 3.0 it has name External Parameter, in later versions it is called Additional Parameter.
The rate of chemical reactions and crystallization depends on different parameters, the first of them is temperature.
Now we have the possibility to use the second parameter in the common kinetic model, where reaction rate depends on two parameters. In the software it is called External Parameter.
Examples of the Additional Parameter:
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Partial pressure of reactive gaseous component in the surrounding atmosphere, like oxidation reactions.
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Pressure of inert atmosphere for reversing reactions with gas production.
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Intensity of UV light for curing of photopolymers.
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Initial concentration of reactive component.
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Different reactant concentrations in two-component reactions (Kinetics Neo version 3.5 or later)
Project with Additional Parameter
Using of Additional Parameter in the kinetic project must be set in the Project properties in Settings (File - Project):
Data Source
For each data file in the Source Data the value of the additional parameter must be set during Data Preparation:
Please use bar units for pressure, and relative units for other external parameters, where data with value 1 for External Parameter must be present.
Kinetic Model
Only Model-Based analysis can be used to create the kinetic model depending on temperature and additional parameter (like pressure).
Model-Free analysis is not suitable for kinetic analysis of such data in Kinetics Neo.
If the project uses Additional Parameter, then each reaction step in the kinetic model contains the checkbox to set if this step depends on this Additional Parameter or not. If selected parameter for the project is Pressure, then the checkbox Depends on: Pressure is shown.
In multi-step models the dependence on the Additional Parameter can be set for each reaction step separately. For example, some reactions steps in the model are pressure-dependent, and other steps - not.
Each reaction step, depending on the Additional Parameter, contains additional parameter for this dependence. For example, for pressure-dependent reactions the name of additional parameter is nPressure. The value of this parameter can be different for different reaction steps in the kinetic model.
Simulation: Predictions and Optimization
If the project uses Additional Parameter, then the Simulation (both Prediction and Optimization) can be done for given value of additional parameter.
The next Dynamic Prediction is done for pressure-dependent reaction for different heating rates at pressure 0.5 bar.
How To Guide
The example of kinetic model for pressure-dependent reaction can be found on our web site in our guide How to Analyze Reversible Reaction with Reactive Gaseous Reactant.