An alternative approach to kinetic analysis of temperature-programmed reaction data

Area of Science:

• Chemical Kinetics
• Materials Science
• Reaction Engineering

Background:

• Kinetic computations are efficient for many physical processes but lack methods for complex chemical reactions.
• Multi-stage reactions require advanced kinetic analysis techniques for accurate modeling.

Purpose of the Study:

• To develop and validate a novel method for kinetic analysis of multi-stage chemical reactions using temperature-programmed reaction data.
• To apply the method to the reduction of iron(iii) oxide and assess its performance and applicability.

Main Methods:

• Developed a system of kinetic differential equations accounting for all reaction stages.
• Optimized kinetic parameters (activation energy, preexponential factors) for each stage.
• Employed cubic splines for conversion functions reflecting surface area changes.
• Tested the method on temperature-programmed reduction (TPR) data of iron(iii) oxide annealed at various temperatures.

Main Results:

• Demonstrated the method's stability and performance across different temperature regimes.
• Identified stage- and heating rate-dependent reduction peculiarities of iron(iii) oxide.
• Assessed the influence of material morphology on reduction kinetics via preexponential factors.
• Successfully reproduced initial particle size distribution from kinetic data, correlating well with experimental laser diffraction results.

Conclusions:

• The proposed method provides a robust framework for kinetic analysis of complex reactions.
• It enables detailed comparison of material structural characteristics through kinetic data.
• The approach accurately links kinetic parameters to physical properties like particle size distribution.