High-Efficiency Mist Eliminators


Lebedev, Y.N.; Zilberberg, I.A.; Lozhkin, Y.P.; Chekmenev, V.G.

Chemistry and Technology of Fuels and Oils 38(1): 42-45

2002


Mist eliminators are designed to catch: liquid drops from the gas stream or vapor in treating and drying natural gas; coke, metal, and asphaltene particles in vacuum distillation of atmospheric resid; solvent drops in selective treatment of lube oils, and for separating liquid drops in separators installed in front of compressors, etc.

Chemistry
and
Technology
of
Fuels
and
Oils,
Vol.
38,
No.
1,
2002
HIGH-EFFICIENCY
MIST
ELIMINATORS
Yu.
N.
Lebedev,
I.
A.
Zi1'berberg,
Ya.
P.
Lozhkin,
and
V.
G.
Chekmenev
UDC
661.973.1
Mist
eliminators
are
designed
to
catch:
liquid
drops
from
the
gas
stream
or
vapor
in
treating
and
drying
natural
gas;
coke,
metal,
and
asphaltene
particles
in
vacuum
distillation
of
atmospheric
resid;
solvent
drops
in
selective
treatment
of
lube
oils,
and
for
separating
liquid
drops
in
separators
installed
in
front
of
compressors,
etc.
Mist
eliminators
of
sieve
design
consisting
of
blocks
of
joined
metallic
or
nonmetallic
screens
are
the
most
widespread.
They
are
installed
in
vertical
and
horizontal
vessels
in
an
entire
section
or
before
the
connections
of
the
vapor
(gaseous)
products
outlet.
Ultraset,
developed
at
Kedr-89
Co.,
is
this
type
of
mist
eliminator.
Its
design
and
manufacturing
method
are
protected
by
Russian
Federation
patents.
Ultraset
mist
eliminators
have
been
tested
in
experimental
and
semi-industrial
plants
and
in
revamping
the
separators
and
mass-exchange
vessels
in
gas
processing
and
petroleum
refining
plants
and
in
natural
gas
scrubbing
absorbers.
Ultraset
mist
eliminators
(Fig.
1)
made
of
connected
corrugated
screen
are
installed
in
vessels
from
300
to
10,000
mm
in
diameter.
Mist
eliminators
less
than
500
mm
in
diameter
are
supplied
in
the
form
of
rolls
of
corrugated
joined
screen
attached
to
a
special
frame
more
than
500
mm
in
diameter
in
the
form
of
blocks
that
pass
freely
through
the
manhole
in
the
vessel,
which
is
500
mm
in
diameter.
The
blocks
consist
of
a
frame
filled
with
a
joined
corrugated
sleeve
screen
and
couplers
that
fix
the
position
of
the
sleeve.
The
rigid
frame
ensures
the
necessary
strength
in
assembly
and
use.
The
maximum
Fig.
1.
Ultraset
corrugated
joined-screen
mist
eliminator
of
the
block
type.
Kedr-89
Co.
Translated
from
Khimiya
i
Tekhnologiya
Topliv
i
Masel,
No.
1,
pp.
32
33,
January
February,
2002.
42
0009-3092/02/3801-0042$27.001
2002Plenum
Publishing
Corporation
0.798
0.532
;
5
.,
<1
0.266
56
r
2
/m
3
70
0
2
3
4
w,
m/sec
5
Fig.
2.
Pressure
loss
Ap
in
the
Ultraset
mist
eliminator
with
a
different
specific
surface
area
(see
figures
on
curves)
vs.
gas
flow
rate
w.
1
Fig.
3.
String
mist
eliminator
block.
dimensions
of
the
block
are:
length:
1008
mm,
width:
400
mm,
height:
130
mm;
maximum
weight:
11
kg.
The
mist
eliminator
is
installed
in
the
vessel
on
a
support
grate.
The
Ultraset
mist
eliminator
is
highly
reliable
in
use.
Its
design
virtually
excludes
possible
deformation
of
the
blocks
and
perturbation
of
the
continuity
of
the
layers
in
normal
conditions
of
use.
In
addition,
it
permits
maximum
utilization
of
the
useful
area
of
the
vessel
so
that
high
output
in
gas
is
ensured
with
maximum
separation
efficiency.
The
separation
efficiency
is
greater
than
99%,
and
small
particles
of
liquid
3-5
mm
in
size
are
trapped.
Ultraset
mist
eliminators
of
different
packing
density
(specific
surface
area)
are
mass
produced
by
Dal'
CJSC
(Saratov)
using
screens
made
of
different
metals
and
synthetic
materials.
When
screens
made
of
metal
wire
0.2-0.32
mm
thick
are
used,
the
specific
surface
area
of
the
mist
eliminator
can
vary
from
170
to
500
m
2
/m
3
.
43
1
\.3
2
5
9
13
17
w,
m/sec
Fig.
4.
Efficiency
E
of
separation
vs.
gas
flow
rate
w
in
working
section
of
the
mist
eliminator:
1)
joined
screen;
2)
Vane-Type;
3)
string
type.
2
4
8
12
16
20
F
,
Pa05
Fig.
5.
Pressure
loss
Ap
vs.
F
factor
(vapor
load)
for
a
separator
with
a
mist
eliminator:
1)
bound
screen;
2)
string
type.
Ultraset
mist
eliminators
are
installed:
at
the
gas
outlet
from
horizontal
and
vertical
vessels;
at
the
top
of
mass-exchange
towers
to
prevent
entrainment
of
liquid
from
the
trays;
above
the
feedstock
input
into
the
tower
to
trap
dropping
liquid.
When
the
mist
eliminator
is
horizontally
positioned,
the
gas
(vapor)
stream
with
the
dropping
liquid
in
it
enters
from
below.
The
gas
passes
freely
through
the
series
of
wires,
while
the
liquid
drops
are
retained
on
the
surface
of
the
wire,
become
larger,
spread
to
the
lower
surface
of
the
mist
eliminator,
and
then
fall
through.
The
gas
(vapor)
is
freed
of
dropping
liquid
in
this
way.
Selection
of
the
dimensions
(diameter,
height,
specific
surface
area)
of
the
mist
eliminator
is
a
function
of
the
working
conditions
in
the
vessel
and
the
process
requirements
for
the
scrubbed
gas.
The
acceptable
F
s
factor
(vapor
load)
for
the
mist
eliminator
is
2.7-4.5
Pa"
as
a
function
of
the
density
of
the
gas
and
the
physical
properties
of
the
gas
and
liquid.
The
pressure
drop
in
a
joined-screen
mist
eliminator
varies
from
0.029
to
0.245
kPa
as
a
function
of
the
screen
packing
density,
gas
flow
rate,
and
load
in
liquid.
The
results
of
bench
tests
of
mist
eliminators
with
a
different
specific
surface
area
in
a
water—air
system
are
shown
in
Fig.
2.
Ultraset
mist
eliminators
are
successfully
operating
in
vessels
at
Astrakhan'
GPP:
in
172V01
wet
gas
(diameter:
2200
mm)
and
S-206
(diameter:
1600
mm)
hydrogen
sulfide
separators;
the
mist
eliminator
diameter
in
the
latter
vessel
is
800
mm.
These
devices
were
used
in
revamping
the
EDU—AVT-6
plant
at
Angarsk
Refinery.
They
are
equipped
with:
an
atmospheric
tower
at
the
top
(3400
mm
in
diameter)
and
over
the
feedstock
input
(7000
mm
in
diameter);
K-10
and
K-11
vacuum
towers
under
the
vapor
takeoff
connections
to
the
head
line
(two
mist
eliminators
in
each
tower:
1200
mm
in
diameter
in
the
K-10
and
800
mm
in
diameter
in
the
K-11).
Ultraset
mist
eliminators
are
successfully
operating
in
separators
and
reflux
containers
in
the
L-35-11/450K
reforming
plant
with
preliminary
hydrotreating
at
Komsomol'
sk
Refinery—Rosneft'
OJSC.
String
mist
eliminators
(Fig.
3)
have
also
been
created
at
Kedr-89
Co.
In
contrast
to
Ultraset,
which
operates
in
a
counterflow
regime,
they
operate
in
a
cross-flow
regime.
These
mist
eliminators
are
packages
consisting
of
rows
of
parallelly
positioned
vertical
metallic
or
synthetic
fibers.
The
number
of
packages
installed
is
a
function
of
the
gas
flow
rate
and
required
degree
of
scrubbing.
The
gas
stream
containing
dropping
liquid
passes
through
the
package
with
vertical
rows
of
fibers.
The
liquid
drops
are
retained
on
the
fibers
and
become
larger
,
forming
circular
films
of
liquid
that
spread
under
the
effect
of
gravity.
The
design
allows
varying
the
fiber
diameter,
step
between
fibers,
number
of
rows
over
100
95
W
90
2400
1600
.c"
800
0
44
the
gas
path,
fiber
material,
and
other
parameters
as
a
function
of
the
conditions
of
use
and
required
separation
efficiency.
The
output
of
the
string
mist
eliminator
is
five
times
higher
for
the same
efficiency
than
the
joined-screen
mist
eliminators
and
approximately
two
times
higher
than
for
the
Vane-Type
plate
mist
eliminators
widely
used
abroad
(Fig.
4).
The
pressure
drop
in
the
string
mist
eliminators
is
one
order
of
magnitude
less
than
in
sieve
separators
(Fig.
5).
String
mist
eliminators
were
tested
on
experimental
benches
and
widely
introduced
in
industry.
Kedr-89
Co.
has
accumulated
important
experience
in
using
them
in
petroleum
refining,
petrochemical,
and
petroleum
and
gas
production
enterprises:
in
separators
on
the
G-43/107
plant
at
Moscow
Refinery,
in
typical
LK-6u
plant
separators
and
absorbers
at
Mazheiksk
and
other
refineries,
in
the
KM-2
plant
desorber
at
Slavneft—Yarloslavnefteorgsintez
OJSC.
These
mist
eliminators
are
usually
installed
in
vacuum
towers
above
the
feedstock
input
on
the
blind
tray
steam
nozzles
from
which
the
separated
liquid
is
taken
off.
They
operate
in
vacuum
towers
from
5.5
to
9
m
in
diameter
in
typical
KT,
EDU-AVT-6,
AVT-2,
and
many
other
plants
and
ensure
the
required
color
and
carbon
content
of
the
distillates
taken
off
with
high
F
factors
(vapor
loads)
and
low
pressure loss.
This
is
especially
important
in
revamping
vacuum
towers
to
increase
their
productivity
or
to
take
off
distillates
of
improved
quality.
45