Utilizing the Kinetics 4.x numeric code and KineticsGUI developed jointly by Lawrence Livermore National Laboratory and HISI Analytical Technologies, Kinetics2000 provides the user numerous options for reducing and calculating kinetic parameters from a wide range of experimental techniques and data.
The processing options within Kinetics2000 include the following models:
There are 4 basic functions within the program:
As shown in the opening screen, menu buttons direct the user to these functions as:
In the Data analysis mode, Kinetics2000 can be used to view, modify, transform, and reduce kinetic input files from pyrolysis instruments such as Humble's SR Analyzer (bulk) and Py-MACT-GC (compositional) kinetics instruments. However, it can be used to determine decomposition kinetics from other pyrolysis and non-pyrolysis data such as TGA data. Other data such as fraction reaction results derived from hydrous pyrolysis, MicroScale Sealed Vessel (MSSV), or other closed system pyrolysis experiments can be readily processed in the Kinetics2000 software.
Baselines can be adjusted, peaks smoothed and thinned, and temperatures adjusted by selecting one of the various commands under Data options. Any modifications can be undone using the Reset option before saving a file.
Data files can be edited to set lower and upper temperature or time limits. Normalization of data can be completed with user selected scaling.
Temperatures may be adjusted or corrected. For example, data from Rock-Eval® II instruments, that typically require a 35-40° C temperature correction from nominal to true in-sample temperature, can easily be corrected using the Correct T option.
Reaction data can be easily converted using the integrate and differentiate commands. After conversion data can be saved in these formats.
Data smoothing can accomplished using a 3-point moving average correction for either temperature or reaction data.
The Analysis mode is the most powerful aspect of the Kinetics2000 software. It includes numerous kinetic models enabling an accurate assessment of reaction rates regardless of chemical composition and structure. It has been shown that certain reactions are not accurately modeled by discrete model and Gaussian or Nucleation models provide more accurate results in these cases.
After file selection using Windows file selection capabilities with single or multiple file selection, data is initially processed using approximate models to determine the initial Arrhenius (A) factor. The program defaults to certain ranges for the Arrhenius constant based on this initial assessment, but these values may be changed at the users discretion. The calculations are based on various other options selected by the user primarily depending on the model selected.
Numerous options are available within a given model. For example, within the discrete model data may be processed using a fixed activation energy spacing and ranges, free or fixed A factors, and experimental data type such as reaction rate of cumulative reacted.
Batch file processing allow processing of numerous models using a single control file. Results are written to a user specified directory and file name. These results may be viewed by selecting the View button from the main menu of Kinetics2000. Results may be viewed or printed as partial or full kinetics calculation reports. Curve fitting results and distribution of activation energies with the associated A factor can be viewed, printed, or written to bitmap or metafiles for pasting into documents or reports.
Kinetic parameters are not easily compared particularly when A factors are different. Casual assessment of reaction rates by simply comparing principal activation energies is nonsensical. Fixing the A factor is one solution, but assessment of reaction rates under conditions of interest is more meaningful.
More detailed reaction rate modeling can be completed in Humble's KMod program. KMod models nonisothermal and isothermal heating rates. It includes graphical display of results of fraction reacted, cumulative reacted, and the distribution of activation energies with A factor. Individual graphs can be saved as metafiles for pasting into reports or other documents.
In the Apply mode, arbitrary thermal histories may be input into the Kinetics2000 program to compare reaction rates. The example below illustrates that decomposition begins at about 100° C and is virtually complete at 200° C at the heating rate modeled.
Copyright © 1999-2002 Humble Instruments &
Services, Inc.. All rights reserved.
Revised: