(454d) Kinetics Insights of Waste Plastic Pyrolysis with Auto-Fragment Modeling (AFM)

For complex systems such as plastics, it’s a huge challenge to build detailed kinetics model to unravel the complicated process due to limited computation resources and time. Therefore, it is necessary to develop new method to tackle the long-lasting issues including exponentially increasing number of isomers and reactions and uncertain accuracy of extrapolation for fitted parameters lumping methods. To overcome difficulties mentioned above, we propose a framework called Auto-Fragment Modeling (AFM) which targets to build detailed kinetic models for heavy hydrocarbons. The method treats large molecules as sliced pieces called fragments and use fragments to construct kinetics model since similar structures will likely to conduct similar reactions. Each piece of fragment represents different part of the original molecules which share common structures among all other species in the system.

This fragment method utilizes Reaction Mechanism Generator (RMG), an open-sourced software, to estimate rate coefficient and thermochemical properties derived from high-accuracy quantum chemistry. Previously we have shown some results for polyethylene (PE) with promising insights by capturing important chemistry and other product information. The framework itself as well as the generated models have been improved with more insights discovered. There are still some technical challenges under development for more accurate predictions on heavy systems.