
REVIEW
OF
SCIENTIFIC
INSTRUMENTS
83,
105107
(2012)
A
test
stand
for
the
evaluation
of
high
efficiency
mist
eliminators
Paxton
K.
Giffin,a
)
Michael
S.
Parsons,
and
Charles
A.
Waggoner
Institute
for
Clean
Energy
Technology,
Mississippi
State
University,
205
Research
Blvd,
Starkville,
Mississippi
39759,
USA
(Received
12
June
2012;
accepted
19
September
2012;
published
online
11
October
2012)
High
efficiency
mist
eliminators
(HEME)
are
airstream
filtering
elements
primarily
used
to
remove
liquid
and
solid
aerosols.
HEME
elements
are
designed
to
reduce
aerosol
load
on
downstream
high
efficiency
particulate
air
filters
and
to
have
a
liquid
particle
removal
efficiency
of
99.5%
for
aerosols
as
small
as
1µm
in
size.
The
test
stand
described
herein
is
designed
to
evaluate
the
loading
capacity
and
filtering
efficiency
of
a
single
HEME
element.
The
loading
capacity
was
determined
with
or
without
use
of
a
water
spray
cleaning
system
to
wash
the
interior
surface
of
the
element.
The
HEME
element
is
challenged
with
a
liquid
waste
surrogate
using
Laskin
nozzles
and
large
dispersion
nozzles.
The
waste
surrogate
used
was
a
highly
caustic
solution
with
both
suspended
and
dissolved
solids
representative
of
actual
exposures
at
mixed,
hazardous,
and
radiological,
waste
treatment
facilities.
The
filtering
efficiency
performance
was
determined
by
challenging
the
element
with
a
dried
waste
surrogate
aerosol
and
di-octyl
phthalate
intermittently
during
the
loading
process.
Capabilities
of
the
test
stand
and
representative
results
obtained
during
testing
are
presented.
©
2012
American
Institute
of
Physics.
[http://dx.doi.org/10.1063/1.4757581]
I.
INTRODUCTION
High
efficiency
mist
eliminators
(HEME)
are
filtering
elements
primarily
used
to
remove
liquid
aerosols
from
an
airstream.
HEME
elements
are
designed
to
have
a
liquid
par-
ticle
removal
efficiency
of
99.5%
for
aerosols
as
small
as
1
p,m
in
size.
1
These
elements
are
commonly
used
to
re-
move
aerosols
from
off-gas
systems
at
mixed
waste
treat-
ment
facilities.
A
lack
of
performance
data
presents
an
is-
sue
with
these
units.
Some
assumptions
need
to
be
verified.
One
such
verification
needed
is
determining
the
loading
ca-
pacity.
The
HEME
elements
are
assumed
to
have
a
high
load-
ing
capacity
because
they
are
typically
continuously
misted
and
intermittently
flushed
with
a
water
spray
that
reduces
the
buildup
of
particle
deposits.
The
impact
of
an
inopera-
ble
water
spray
system
is
another
item
that
requires
investiga-
tion.
The
effect
of
an
inoperable
water
spray
on
the
loading
capacity
is
unknown.
It
is
suspected
that
without
the
water
spray,
the
HEME
filters
will
experience
rapid
buildup
of
solid
aerosols
which
will
greatly
reduce
the
particle
load-
ing
capacity
of
the
element.
The
test
stand
presented
is
de-
signed
to
evaluate
the
loading
capacity
and
filtering
efficiency
of
HEME
elements.
The
loading
capacity
of
a
HEME
ele-
ment
can
be
determined
both
with
and
without
the
use
of
a
wash
down
procedure.
The
representative
test
results
il-
lustrate
the
effects
of
challenging
a
HEME
element
with
a
highly
caustic
hazardous
waste
surrogate.
The
surrogate
is
dispersed
using
both
Laskin
type
and
typical
atomizing
spray
nozzles.
The
filtering
efficiency
(FE)
of
the
element
was
deter-
mined
using
a
dried
waste
surrogate
and/or
di-octyl
phthalate
(DOP).
The
following
tests
display
the
capabilities
of
the
test
equipment.
0
Author
to
whom
correspondence
should
be
addressed.
Electronic
mail:
icet.msstate.edu
.
A.
Previous
testing
Filtration
research
at
ICET
began
in
2001
with
the
DOE
sponsored
high
efficiency
particulate
air
(HEPA)
Filter
Monitoring
Project.
The
research
evaluated
filters
based
on
the
American
Society
of
Mechanical
Engineers
(ASME)
Code
on
Nuclear
Air
and
Gas
Treatment
(AG-1).
2
Section
FC
filter
units.
Previous
studies
of
square
0.3
m
x
0.3
m
x
0.29
m
(12
in.
x
12
in.
x
11.5
in.)
HEPA
filters
have
inves-
tigated
moisture
failure,
source
term
loading,
seal
and
pinhole
leaks,
and
media
velocity.
Details
related
to
design,
construc-
tion,
and
operation
of
the
test
stand
utilized
in
these
research
efforts
have
been
published.
3
Discussions
of
the
experimental
design
related
to
these
research
efforts
have
been
presented
at
several
conferences
and
published.
4
These
discussions
in-
clude
aerosol
generation,
types
of
filters
tested,
and
aerosol
measurement
instrumentation
utilized.
Further
studies
conducted
by
ICET
include
lifecycle
test-
ing
of
HEPA
filters
under
both
ambient
and
elevated
condi-
tions.
These tests
were
conducted
on
ASME
AG-1
Section
FK
radial
flow
representative
filters
with
both
safe
and
re-
mote
change
filter
designs.
Ambient
condition
testing
was
performed
at
21.1
°C-26.7
°C
(70
°F-80
°F)
and
40%-60%
relative
humidity
(RH),
while
the
elevated
condition
testing
occurred
at
54.4
°C
(130
°F)
and
50%
RH
or
greater.
B.
Test
stand
performance
and
data
quality
requirements
The
test
stand
must
be
capable
of
challenging
the
HEME
elements
with
a
variety
of
test
conditions
to
provide
relevant
results.
To
test
different
element
designs
at
different
media
ve-
locities,
the
test
stand
needs
flexibility
in
its
volumetric
flow
rate
capabilities.
These
capabilities
include
the
ability
to
mon-
itor
airstream
temperature
and
relative
humidity.
A
wide
va-
riety
of
wet
and
dry
aerosol
challenge
agents
are
available.
0034-6748/2012/83(10)/105107/12/$30.00
83,
105107-1
©
2012
American
Institute
of
Physics