1 research outputs found
Temperature Extrapolation of Molecular Dynamics Simulations of Complex Chemistry to Microsecond Timescales Using Kinetic Models: Applications to Hydrocarbon Pyrolysis
We
develop a method to construct temperature-dependent kinetic
models of hydrocarbon pyrolysis, based on information from molecular
dynamics (MD) simulations of pyrolyzing systems in the high-temperature
regime. MD simulations are currently a key tool to understand the
mechanism of complex chemical processes such as pyrolysis and to observe
their outcomes in different conditions, but these simulations are
computationally expensive and typically limited to nanoseconds of
simulation time. This limitation is inconsequential at high temperatures,
where equilibrium is reached quickly, but at low temperatures, the
system may not equilibrate within a tractable simulation timescale.
In this work, we develop a method to construct kinetic models of hydrocarbon
pyrolysis using the information from the high-temperature high-reactivity
regime. We then extrapolate this model to low temperatures, which
enables microsecond-long simulations to be performed. We show that
this approach accurately predicts the time evolution of small molecules,
as well as the size and composition of long carbon chains across a
wide range of temperatures and compositions. Further, we show that
the range of suitable temperatures for extrapolation can easily be
improved by adding more simulations to the training data. Compared
to experimental results, our kinetic model leads to similar compositional
trends while allowing for more detailed kinetic and mechanistic insights