(146c) Molecular-Level Kinetic Modeling in Thermochemical Conversions: Software Tools and Their Applications

The considerable interest in molecule-based models of the structure and reactions of petroleum, biomass and other unconventional energy resources is motivated by the need to predict reaction properties.  This is because the molecular composition is an optimal starting point for the prediction of mixture properties. The potential advantages of molecule-based model­ing are thus clear. Less readily apparent, how­ever, is that the development and operation of molec­ular models comes with a large requirement for model construction and solution time as well as analytical and reactivity information.

The challenge of building molecule-based models is due to the staggering complexity of the complex reaction mixtures.  There will often be thousands of potential molecular and intermediate (e.g., ions or radicals) species.  The sheer size of the thus-im­plied modeling problem creates a con­flict between the need for molecular detail and the formulation and solution of the model.  Clearly, the use of the computer to not only solve but also formulate the model would be helpful in that it would allow the modeler to focus on the ba­sic chemistry, physics and approximations of the model.

Our recent work has led to the development of the Kinetic Modeler’s Toolbox (KMT), which organizes software tools for an automated construction, solution and optimization of detailed kinetic models.  KMT’s Composition Modeling Editor (CME) transforms bulk analytical chemistry into a molecular description of the feedstock.  This casts the modeling problem in molecular terms.  Reactivity information is then organized in terms of quantitative linear free energy relationships.  KMT’s INGen tool allows for the model equations to be built and coded on the computer.  KMT’s Kinetic Model Editor (KME) allows for the solution of this chemical reaction network, in the context of the chemical reactor, which provides a prediction of the molecular composition that can then be organized into any desired commercially relevant outputs.

This approach is illustrated through the development of molecule-based models for refinery units and biomass pyrolysis and hydrotreating.