FY2010 - Oak Ridge National Laboratory

Seed Money Fund—
Energy and Transportation Science Division
Mission Relevance
In joint discussions among the national labs and DOE, thermochemical catalytic pyrolysis has been
identified as one of the most promising areas for near-term research and development towards production
of renewable transportation fuels from biomass. Currently, there are no comprehensive simulation tools
that can model the existing pilot-scale pyrolysis reactors being used by national labs to develop a basic
understanding of the chemistry and kinetics of biomass pyrolysis and which can also be used to evaluate
how those results can be scaled up to commercial process conditions. Such tools are needed to interpret
results from and guide experiments and assessment commercial process options. DOE’s Integrated
Biorefinery platform views computational scale-up tools as a major technical challenge and objective.
Along with DOE, both the Department of Agriculture and the Department of Defense have identified
biomass pyrolysis as a major potential source of renewable transportation fuels with tie-ins to sustainable
land use, carbon sequestration, and energy security.
Results and Accomplishments
During FY 2010 we were able to recruit Sudharshan Renganathan, a post-Masters researcher from
Georgia Institute of Technology, to assist in the modification and validation of the MFIX code for
simulating pyrolysis of wood. Sudharshan came to ORNL last June. Under the direction of Sreekanth
Pannala and Charles Finney, he has spent most of his effort in defining values of several key
hydrodynamic and heat transfer parameters in MFIX needed to simulate the conditions typical for
bubbling bed wood pyrolysis studies currently being run at the National Renewable Energy Laboratory
(NREL) and the Pacific Northwest National Laboratory (PNNL). In addition, Sudharshan has also
expanded his MFIX parameter evaluations to include pyrolysis reactors at the Korean Institute of Science
and Technology (KIST), with which we have recently begun a collaboration.
For the steady-state reactor model, Stuart Daw has reviewed and modified key submodels in the original
FORTRAN code used to account for bubble dynamics and bed expansion, and he has added new
submodels that account for wood particle segregation (relative to the primary bed particles), particle heatup
and devolatilization rates, and volatile yield and composition (including tars). It is expected that in the
next few weeks all of the steady-state submodels will be implemented in MatLab and available to begin
studies of parametric sensitivity and trend comparisons with MFIX and experimental pyrolysis data from
the literature and our collaborators.
A $10,000 subcontract was also implemented with Prof. J. S. Halow at Waynesburg University in
Pennsylvania to provide data from experimental ambient temperature measurements of wood particle
mixing in a full-scale bubbling bed reactor built to simulate the experimental laboratory bubbling bed
reactor at NREL used for measuring pyrolysis kinetics. Prof. Halow utilizes a unique magnetic tracking
system (developed previously in collaboration with ORNL) to directly monitor the motion of simulated
biomass particles as they mix with and segregate from the primary bed particles. The mixing and
segregation processes are critical to the ultimate yields of liquid hydrocarbons from pyrolysis because
they directly affect the degree of contacting between the biomass particles and the other gases and solids
in the reactor. This is especially important in catalytic pyrolysis, because the catalyst is typically present
on the surface of the primary bed particles.
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