Chemical Engineering Journal,
Journal Year:
2024,
Volume and Issue:
484, P. 149478 - 149478
Published: Feb. 7, 2024
ThermoCatalytic
Decomposition
of
methane
(TCD)
has
shown
great
potential
for
synthesis
valuable
carbon
nanomaterials
as
well
hydrogen
production,
however
due
to
the
importance
phenomena
operating
at
different
scales,
it
is
a
complex
process
model
and
predict.
During
TCD
decomposed
gas
solid
carbon.
Carbon
accumulated
on
catalyst
particle
leads
larger
but
less
active
particles.
In
this
study,
Computational
Fluid
Dynamics-Discrete
Element
Method-Multi
Grain
Model
(CFD-DEM-MGM)
was
employed
investigate
two
catalytic
fluidized
bed
reactors
with
same
dimensions.
Case-1
involved
batch
particles
staying
in
reactor
during
process,
while
Case-2
featured
continuous
removal
from
bottom
introduction
fresh
side.
Results
showed
that
had
lower
growth
reduced
deactivation
limited
residence
time,
yet
demonstrated
higher
production
conversion.
Case-1,
particles,
experienced
bubble
formation,
removal/introduction
enhanced
solids
mixing.
Internal
diffusion
limitations
affected
performance,
emphasizing
CFD-DEM-MGM
model's
optimizing
design
gas-solid
contacting
process.
Physics of Fluids,
Journal Year:
2025,
Volume and Issue:
37(2)
Published: Feb. 1, 2025
Particle
fluidization
technology
is
often
involved
in
biomass
industrial
applications.
However,
the
utilization
of
particles
requires
gas–solid
flow
and
processes,
such
as
heat
transfer
reaction
transformation.
Therefore,
this
paper,
pellets
were
processed
into
cylindrical
designed
with
five
aspect
ratios
(AR
=
0.5,
1.0,
1.5,
2.0,
3.0).
The
kinetic
characteristics
different
a
bubbling
fluidized
bed
analyzed
from
macroscopic
microscopic
perspectives
using
Computational
Fluid
Dynamics-Discrete
Element
Method.
simulation
results
show
that
higher
sphericity
1),
there
obvious
particle
aggregation
near
wall,
height,
more
asymmetric
flux
distribution.
Increasing
gas
superficial
velocity
helps
to
improve
mixing
quality
particles,
convective
transfer,
temperature
cooling
rate,
uniformity
contact
force
between
much
larger
than
gas–particle
interaction
force,
mainly
concentrated
on
both
sides
wall.
ratio
smaller
uniformly
distributed
at
Furthermore,
when
AR
>
1,
drag
lift
gradually
increase
ratio,
faster
decreases,
standard
deviation
temperature.
Energies,
Journal Year:
2025,
Volume and Issue:
18(6), P. 1504 - 1504
Published: March 18, 2025
The
heat
transfer
(HT)
characteristics
of
cylindrical
biomass
particles
(CBPs)
in
fluidized
beds
(FBs)
are
important
for
their
drying,
direct
combustion,
and
thermochemical
transformation.
To
provide
a
deeper
insight
into
the
complex
mechanisms
behind
HT
behaviors
involving
CBPs,
this
study
developed
particle
model
within
framework
computational
fluid
dynamics
coupled
with
discrete
element
method
(CFD-DEM)
which
CBPs
were
characterized
by
super-ellipsoid
model,
has
unique
merit
striking
balance
between
accuracy
efficiency.
newly
considers
particle–particle
(P-P),
particle–wall
(P-W),
fluid–particle
(F-P).
Its
was
verified
comparing
numerical
results
experimental
infrared
thermography
measurements
terms
temperature
evolution
particles.
effects
gas
velocity,
inlet
temperature,
thermal
conductivity
on
investigated
comprehensively.
demonstrated
following:
(1)
Gas
velocity
can
improve
uniformity
bed
distribution
shorten
fluctuation
process
uniformity.
(2)
A
26.8%
increase
leads
to
13.4%
proportion
an
orientation
range
60–90°.
(3)
no
obvious
influence
convective
rate,
or
Chemical Engineering Journal,
Journal Year:
2024,
Volume and Issue:
484, P. 149478 - 149478
Published: Feb. 7, 2024
ThermoCatalytic
Decomposition
of
methane
(TCD)
has
shown
great
potential
for
synthesis
valuable
carbon
nanomaterials
as
well
hydrogen
production,
however
due
to
the
importance
phenomena
operating
at
different
scales,
it
is
a
complex
process
model
and
predict.
During
TCD
decomposed
gas
solid
carbon.
Carbon
accumulated
on
catalyst
particle
leads
larger
but
less
active
particles.
In
this
study,
Computational
Fluid
Dynamics-Discrete
Element
Method-Multi
Grain
Model
(CFD-DEM-MGM)
was
employed
investigate
two
catalytic
fluidized
bed
reactors
with
same
dimensions.
Case-1
involved
batch
particles
staying
in
reactor
during
process,
while
Case-2
featured
continuous
removal
from
bottom
introduction
fresh
side.
Results
showed
that
had
lower
growth
reduced
deactivation
limited
residence
time,
yet
demonstrated
higher
production
conversion.
Case-1,
particles,
experienced
bubble
formation,
removal/introduction
enhanced
solids
mixing.
Internal
diffusion
limitations
affected
performance,
emphasizing
CFD-DEM-MGM
model's
optimizing
design
gas-solid
contacting
process.
