Model-based design of temporal analysis of products (TAP) reactors: A simulated case study in oxidative propane dehydrogenation

TL;DR

This paper demonstrates that model-based design of experiments (MBDoE) enhances the selection of optimal experiments in TAP reactors, improving kinetic model accuracy and enabling mechanism discrimination in oxidative propane dehydrogenation.

Contribution

It introduces and applies a model-based experimental design approach to TAP reactor studies, optimizing experiment selection for kinetic modeling and mechanism identification.

Findings

MBDoE reduces parameter uncertainties more effectively than traditional methods.

Optimal experiments for model divergence can discriminate mechanisms, but re-optimization may eliminate this ability.

Insights into the limitations and potential of MBDoE in transient kinetic experiments.

Abstract

Temporal analysis of products (TAP) reactors enable experiments that probe numerous kinetic processes within a single set of experimental data through variations in pulse intensity, delay, or temperature. Selecting additional TAP experiments often involves arbitrary selection of reaction conditions or the use of chemical intuition. To make experiment selection in TAP more robust, we explore the efficacy of model-based design of experiments (MBDoE) for precision in TAP reactor kinetic modeling. We successfully applied this approach to a case study of synthetic oxidative propane dehydrogenation (OPDH) that involves pulses of propane and oxygen. We found that experiments identified as optimal through the MBDoE for precision generally reduce parameter uncertainties to a higher degree than alternative experiments. The performance of MBDoE for model divergence was also explored for OPDH, with the relevant active sites (catalyst structure) being unknown. An experiment that maximized the divergence between the three proposed mechanisms was identified and led to clear mechanism discrimination. However, re-optimization of kinetic parameters eliminated the ability to discriminate. The findings yield insight into the prospects and limitations of MBDoE for TAP and transient kinetic experiments.