Usefulness of Lumped Kinetic Modeling

Area of Science:

• Chemical engineering
• Materials science
• Reaction kinetics

Background:

• Chemical recycling of plastic waste is crucial for a circular economy, offering an alternative to landfilling and incineration.
• Pyrolysis, gasification, and partial oxidation are key technologies for converting plastic waste into chemical feedstock, reducing reliance on crude oil.
• Accurate kinetic models are essential for designing and scaling up industrial chemical recycling processes.

Purpose of the Study:

• To develop and compare five lumped kinetic models for the co-pyrolysis of low-density polyethylene (LDPE) with a heavy petroleum fraction.
• To evaluate the impact of different lumping strategies (a priori and a posteriori) on model predictive accuracy.
• To assess the influence of these models on the scale-up and predicted operation of industrial reactors.

Main Methods:

• Development of five lumped kinetic models for co-pyrolysis of LDPE and heavy petroleum fraction.
• Application of a priori lumping for four models and a posteriori lumping for the fifth model.
• Product mixture characterization by eight lumps based on boiling point for each model.
• Comparison of model prediction accuracies and deviations.
• Scale-up simulation of an industrial reactor using each developed model.

Main Results:

• All five lumped kinetic models demonstrated similar prediction accuracies and deviations.
• Despite similar overall accuracy, the models exhibited different kinetic parameters.
• The choice of lumping approach (a priori vs. a posteriori) did not significantly alter prediction accuracy.
• Reactor scale-up simulations indicated that all models provided comparable insights into design and operation.

Conclusions:

• Lumped kinetic modeling is a viable approach for simulating plastic pyrolysis, even with complex reaction networks.
• Different lumping strategies yield models with comparable predictive capabilities for co-pyrolysis processes.
• The developed models are suitable for the industrial-scale design and operation prediction of chemical recycling reactors.