(368h) Modeling Reactive Heat and Mass Transfer in Biogas Production Unit

Biogas
production is one of the existing ways to produce renewable energy
from wastes. This is mainly governed by multiphase transport
processes and biological reactions without oxygen. Consequently, a
fine description of those phenomena at the production unit scale is
required in order to characterize the biogas production. It is
necessary to take into account the various heterogeneities (phase
distribution, gas composition, temperature) inside the production
unit to accurately predict the installation efficiency.

The goal of
this work is the development and the validation of a CFD software
solving the complete set of equations constituting the model. The
code is developed using the OpenFOAM®
platform, an open-source CFD toolbox highly programmable, which
enables parallel computation and disposes powerful pre- and
post-processing tools.

The set of
equations is solved sequentially, decoupling the hydrodynamics part
from component transport and heat transfer. First, gas and liquid
flows in the porous medium are solved using the IMPES method
(Implicit Pressure and Explicit Saturation) with, for each equation,
an adaptive independent time-step. Then, the reactive mass transfer
is solved decoupling the purely reactive part from the transport
part. Finally, heat transfer is computed using the fields previously
updated.

Results on
the hydrodynamic part are first validated on the Buckley-Leverett
case by comparison with the analytical results. Then, results of the
complete model are compared with experimental data obtained on a
pilot unit.