Industrial & Engineering Chemistry Research,
Journal Year:
2023,
Volume and Issue:
62(39), P. 16139 - 16153
Published: Sept. 21, 2023
To
improve
heat
transfer
in
packed
bed
temperature
swing
adsorption
processes
for
direct
air
capture,
reactors
with
embedded
cylindrical
heating
pipes
have
been
developed.
Optimization
of
these
inherently
dynamic
systems
currently
requires
a
transient
two-dimensional
(2D)
model,
which
is
computationally
very
expensive.
In
the
present
work,
method
therefore
developed
to
translate
2D
fixed
geometry
into
an
equivalent
one-dimensional
(1D)
model
by
placing
line
sources
along
direction
modeled
1D.
determine
sources'
strength,
Nusselt
correlation
required.
It
found
that
staggered
cylinder
configurations,
single
works
well.
For
in-line
analytical
correction
factor
successfully
account
effect
thermal
wake
upstream
cylinders
on
around
cylinder.
The
1D
translation
approach
then
tested
three
different
cylinder-packing
geometries
at
varying
Péclet
numbers
and
steady-state
simulations.
simulations,
has
maximum
deviation
10%
mean
outlet
from
results
(scaled
difference),
thus
showing
good
agreement.
below
20%
most
conditions,
reasonably
merit
becomes
apparent
when
looking
computational
time:
calculations
are
500
faster
than
calculations.
AIChE Journal,
Journal Year:
2024,
Volume and Issue:
70(5)
Published: March 12, 2024
Abstract
The
understanding
of
complex
fluidization
hydrodynamics
and
chemical
reactions
in
biomass
fast
pyrolysis
fluidized
bed
reactors
is
lacking
requires
further
investigation.
It
urgent
to
develop
accurate
mathematical
models
capable
describing
the
multiphase
reaction
system
pyrolysis.
A
comprehensive
multiscale
model
based
on
coarse‐grained
discrete
element
method
(DEM)‐computational
fluid
dynamics
(CFD)
was
developed
open‐source
MFiX
code.
incorporates
detailed
kinetics
an
intraparticle
model.
To
validate
model,
measurements
were
conducted
a
pyrolyzer,
including
quantifying
segmental
pressure
drop
along
height
determining
yields
compositions
gas,
liquid,
solid
products.
particle
mixing
segregation,
axial
distribution
residence
time,
Lacey
index,
products
investigated.
study
provides
experimental
theoretical
foundations
for
designing
advancing
thermochemical
conversion.
Industrial & Engineering Chemistry Research,
Journal Year:
2023,
Volume and Issue:
62(42), P. 17100 - 17108
Published: July 11, 2023
Bio-oil
(or
tar)
production
by
the
fast
pyrolysis
of
biomass
is
one
important
technological
paths
for
efficient
utilization
and
conversion
biomass.
However,
there
are
many
types
biomasses
with
different
compositions.
There
an
urgent
need
to
select
type
that
more
suitable
produce
bio-oil.
In
this
work,
characteristics
three
main
components
(cellulose,
hemicellulose,
lignin)
in
a
fluidized
bed
reactor
were
studied
establishing
comprehensive
mathematical
model
multiphase
flow-heat
transfer-pyrolysis
reaction
process
using
numerical
simulation
method.
The
two
typical
such
as
hardwood
softwood
contents
further
analyzed.
results
show
yield
bio-oil
or
tar
3%
higher
biochar
6%
lower
compared
at
773
K.
Simulation
demonstrated
high
hemicellulose
content
low
lignin
ideal
feed
pyrolysis.
Heliyon,
Journal Year:
2023,
Volume and Issue:
9(11), P. e21255 - e21255
Published: Oct. 23, 2023
During
the
pyrolysis
process
of
large
particles,
conduction
between
particles
cannot
be
ignored.
In
present
work,
a
numerical
simulation
model
for
biomass
was
established,
which
takes
into
account
within
particles.
Based
on
this
model,
temperature
distribution
inside
particle
during
determined
and
effects
size,
moisture
content,
gas
velocity
heat
transfer
characteristics
were
analyzed.
The
results
showed
that
temperatures
at
different
positions
along
inflow
direction
quite
different,
maximum
difference
about
146.7
K
diameter
10
mm
0.2
m/s.
there
two
peaks
Nusselt
number.
increase
content
prolonged
time.
pyrolysis.
time
with
15
%
1.5
times
longer
than
dry
when
mm.
Increasing
size
decreased
increased
interval
peaks.
can
improve
transfer,
but
effect
too
high
improving
is
limited.
study
great
importance
detailed
understanding
