EPA-650/2-74-129
DECEMBER 1974
Environmental Protection Technology Series
2
vsay
-------
EPA-650/2-74-129
EVALUATION
OF ARONETICS
TWO-PHASE
JET SCRUBBER
by
Joseph D McCain
Southern Research Institute
2000 Ninth Avenue South
Birmingham, Alabama 35205
Contract No. 68-02-1480
ROAP No. 21ADL-004
Program Element No. 1AB012
EPA Project Officer: Dale L. Harmon
Control Systems Laboratory
National Environmental Research Center
Research Triangle Park, North Carolina 27711
Prepared by
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
December 1974
-------
This report has been reviewed by the Environmental Protection Agency
and approved for publication. Approval does not signify that the
contents necessarily reflect the views and policies of tho Agency,
nor docs mention of trade names or commercial products constitute
endorsement or recommendation for use.
11
-------
ABSTRACT
This report presents the results of fractional and
overall mass efficiency tests of the Aronetics, Inc.,
Two Phase Jet Scrubber. The tests were performed on
a full scale scrubber used for controlling particulate
emissions from a ferro-alloy electric arc furnace.
Total flue gas particulate mass concentrations were
determined at the inlet and outlet of the scrubber
by conventional (Method 5) techniques. Inlet and
outlet particulate concentrations as functions of
size were determined on a mass basis using cascade
impactors for sizes from about 0.3 pm to 5 vim, and
on a number basis for sizes smaller than about 1 pm
using optical and diffusional methods.
The text of this report includes brief descriptions
of the ferro-alloy furnace process, the Aronetics
Scrubber, economics of operating the scrubber, the
measurement methods for determining the fractional
efficiency, a time history of the furnace particulate
emissions, and measured fractional efficiencies.
This report was submitted in partial fulfillment of
Contract 68-02-1480 to Southern Research Institute
under the sponsorship of the Environmental Protection
Agency. The work reported here was completed
November 30, 1974.
111
-------
IV
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TABLE OF CONTENTS
Page
ABSTRACT iii
CONCLUSION 1
INTRODUCTION 2
DISCUSSION 6
APPENDICES 24
A - TWO PHASE JET SCRUBBER 24
B - FURNACE OPERATION AND PRODUCTION DATA 31
C - SCRUBBER OPERATING PARAMETERS 32
D - ESTIMATED OPERATING COSTS OF THE
ARONETIC'S TWO PHASE JET SCRUBBER
SYSTEM 34
FIGURES
1 - General Layout of Furnace and
Scrubber System Showing Sampling
Locations 3
2 - Daily Record of Furnace and Scrubber
Operations and Sampling Periods 5
3 - Optical and Diffusional Sizing System.... 9
4 - Inlet Condensation Nuclei Counter Data
(With Diffusion Batteries) Through A
Typical Set of Furnace Operations 10
5 - Inlet Optical Particle Counter Data
Through A Typical Set of Furnace Opera-
tions 11
6 - Average Inlet and Outlet Size Distri-
butions On A Cumulative Concentration
Basis 13
v
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TABLE OF CONTENTS
(Continued)
FIGURES
(Continued) Page
7 - Average Inlet Size Distribution On A
Cumulative Weight Percentage Basis ...... 18
8 - Fractional Efficiency of the Aronetics
Wet Scrubber Calculated From the
Weighted Averages of 30 Inlet (Brink)
and 6 Outlet (Andersen Mark III)
Impactor Tests. Particle Sizes Are
Given As Aerodynamic Diameters
(Density = 1 gm/cm3 ) .................. » • 19
9 - Fractional Efficiency of the Aronetics
Scrubber Based On Optical, Diffusional,
and Impactor Data ....................... 20
Ala - Generalized Two Phase Jet Scrubber
Nozzle .................................. 25
Alb - Generalized Two Phase Jet Scrubber
System .................................. 25
A2 - Variation of Water Droplet Velocity
From Two Phase Jet Nozzle With Water
Temperature ............................. 26
A3 - System Pressure Rise As A Function of
Water Flowrate .......................... 28
Dl - Water Use Rate Required for Achieving
99% Cleaning Efficiency For Various
Particle Sizes .......................... 35
TABLES
I - Scrubber Inlet Loading By Size
Interval ................................ 16
II - Scrubber Outlet Loading By Size
Interval ................................ 17
III - Mass Train (Method 5) Results ........... 22
VI
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SECTION I
CONCLUSIONS
The collection efficiency of the Aronetics Two Phase
Scrubber determined by conventional (Method 5)
techniques on a source producing particulate having
a mass mean diameter of about 3 pm was 95.1 and 96.7%
for two days of testing. Measured fractional efficiencies
were about 70% at 0.01 ym, about 35% at 0.05 ym,
35% at 0.1 ym, 99% at 0.5 ym, 99% at 1 ym, and 99.4%
at 5 ym. The scrubber energy usage during the tests was
approximately 635 JOULES/1000 SCM (17000 BTU/1000 SCF)
at a net pressure rise of 12*s to 16 in. HaO. This
energy usage was a result of using all the process waste
heat available and may have been in excess of the
minimum amount required to achieve the efficiencies
obtained during these tests.
-------
SECTION II
INTRODUCTION
This report presents results of tests conducted
by Southern Research Institute to determine the
capability of the Aronetics, Inc., Two Phase Jet
Scrubber to collect fine particulates. The goals
of the tests were: (1) to determine optimum
operating conditions of the scrubber, (2) to deter-
mine the overall mass efficiency and the fractional
efficiency of the scrubber while operating under
optimum conditions, and (3) to determine the frac-
tional efficiency of the scrubber for some non-optimum
operating conditions as time and circumstances
permitted. Figure 1 is a schematic of the basic
furnace and scrubber system showing the inlet and
outlet sampling locations.
The tests were conducted on a 7.5 MW submerged arc
ferro-alloy furnace at Chromasco, Inc.'s Memphis,
Tennessee facility. The furnace was operating
continuously 24 hours per day, producing approxi-
mately 31 metric tons/day of ferrochrome. The
furnace was tapped at approximate 2 hour intervals
with several charging and stoking operations taking
place at irregular intervals between each consecutive
tap. The actual timing for any one furnace cycle
varied somewhat from the nominal 120 minute tap cycle.
The operations for any one batch were: (1) charging
of the furnace with ore, coke, remelt, and gravel
-------
u>
EMERGENCY
VENT
SCRUBBER
INLET DUCT SAMPL
PORTS .METHOD 5
AND IMPACTORS
SCRUBBER
EXHAUST SAMPLE
PORTS,METHOD 5
AND IMPACTORS
SCRUBBER EXHAUST
SAMPLING POINT
OPTICAL/DIFFUSIONAL
HEAT
EXCHANGER
SCRUBBER
SYSTEM
RECYCLED
WATER ,-(0)
NOZZLE
DEMISTER
GROUND LEVEL
INLET SAMPLING POINT,
OPTICAL/PI FFUSIONAL
Figure 1. General layout of furnace and scrubber system
showing sampling locations.
-------
requiring about 10% of the time for one tap cycle;
(2) stoking, requiring about 8% of the time over one
tap cycle, and (3) tapping, requiring about 12%
of the cycle. Figure 2 shows the time periods during
which the various furnace, scrubber, and measurement
operations took place during the four days of testing.
The highest particulate emission rates occur during
the tapping portion of the operation, with the actual
emission rate and size distribution of the particulate
being quite variable throughout the cycle. This
variability caused some difficulty in both measurement
and interpretation of data as is described in the
discussion section of this report.
The waste process gases, at temperatures of about
920°K (1200°F) from the furnace, are carried through
a duct to a heat exchanger which supplies approximately
480°K (400°F) high pressure water to drive the scrubber
and provide the necessary system draft. The gas
temperature leaving the heat exchanger is about 380 K
(220°F). The draft for the entire furnace and scrubber
system is provided by the two phase jet in the scrubber
module. During operation, the scrubber produces a net
pressure rise from inlet to outlet of 31.8 cm water
gauge (12.5 in. H20) at a gas flow of 227 kg/min
(500 Ibs/min) and 40.6 cm water gauge (16 in. H20) at
a gas flow of 250 kg/min (550 Ibs/min). Typical volumetric
gas flow rates were about 197 m3/roin (6944 SCFM) during
these tests. A description of the operation of the
scrubber is given in Appendix A.
-------
1
2
3
5
6
1900-
1800-
I700|
1600'
1500-
I400i
1300.
1200'
MOO'
IOOQ.
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0800L
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^__— •
DATE -. 6/25 6/26 6/27 6/28
PAP FURNACE 7 - OPTICAL/DIFFUSIONA1
:HARGE FURNACE 25/26 OUTLET 27/28
3TOKE FURNACE 8 - INLET MASS SAMPLIN(
INLET IMPACTOR SAMPLING 9
OUTLET IMPACTOR SAMPLING 10
OUTLET IMPACTOR SAMPLING
- OUTLET MASS SAMPLING
- HEAT EXCHANGER SOOT BLOWING
Figure 2. Daily record of furnace and scrubber operations and
sampling periods.
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SECTION III
DISCUSSION
A total of four measurement techniques were used
during the tests. These were: (1) diffusional
techniques using condensation nuclei counters and
diffusion batteries for determining concentration
and size distribution on a number basis for particles
having diameters less than approximately 0.2 ym, (2)
optical techniques to determine concentrations and
size distribution for particles having diameters
between approximately 0.3 ym and 1.5 ym, (3) inertial
techniques using cascade impactors for determining
concentrations and size distributions on a mass
basis for particles having diameters between
approximately 0.25 ym and 5 ym, and (4) standard
mass train measurements for determining total inlet
and outlet mass loadings.
The useful concentration ranges of both the optical
counter and the condensation nuclei counters are
such that extensive dilution of the gas streams
being sampled was required. Dilution factors of
about 65:1 were used for both inlet and outlet
measurements. In order to insure that condensation
effects were minimal and that the particles were
dry as measured, the diluent air was dried and
filtered, and diffusional driers were utilized in
the lines carrying the diluted samples to the
various instruments.
-------
Because of the size and complexity of the optical
and diffusional measuring systems, and the fact
that only one set of equipment was available for
measurements of this type, it was not possible to
obtain simultaneous inlet and outlet data with
these methods. The system was first installed
at the outlet sampling location, where an attempt
was made to tune the scrubber and all the outlet
data were obtained. Subsequently, the equipment
was moved to the inlet and the necessary inlet
data were obtained. For the purposes of calcula-
ting the efficiency of the scrubber, the assumption
was made that the furnace process was sufficiently
repetitive that the inlet data, as obtained above,
were a valid representation of that which would
have been obtained during the time the outlet
measurements were made. Accuracy in the diffu-
sional measurements was limited by process varia-
tions and the efficiencies derived from these data
are somewhat uncertain. However, the trends in the
fractional efficiencies derived from the data are
probably real and the fractions of the influent
material that penetrate the scrubber are probably
correct to within a factor of two.
The optical data are presented on the basis of equiva-
lent polystyrene latex sizes and the indicated sizes
can differ from the true sizes by factors as large
as two to three. Data obtained using this method
were primarily intended as a means of real time
monitoring of process changes and the results of
-------
changes in the scrubber operation, but also serve
as rough checks on the data obtained with the
cascade impactors. A partial check of the optical
sizing was done using a dynamic sedimentation method,
with reasonable agreement being found between dia-
meters based on settling velocities and the optical
diameters. The sampling system used for obtaining
the optical and diffusional data is illustrated
diagrammatically in Figure 3.
The tests took place on the dates of June 24 through
June 28, 1974, with June 24 primarily used for instru-
mentation setup, checkout, and preliminary measure-
ments. Attempts at optimizing the scrubber operating
parameters were made on June 25 using the optical and
condensation nuclei counters. A combination of a
long heat exchanger time constant and rapid furnace
condition changes made it impractical to optimize
the scrubber operating parameters within the time
available. Therefore the scrubber conditions were
set by a representative of the manufacturer on the
basis of past experience with the system.
Figures 4 and 5 show records made at the scrubber
inlet using the optical and diffusional systems.
Figure 4 is condensation nuclei/diffusion battery
data which correspond to particulate concentrations
for particles having diameters larger than .01 and
.06 ym, respectively. These data were taken over
a 105 minute period on June 28 and cover an interval
of time corresponding roughly to a typical furnace
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Flowmeters
Cyclone Pump
Diffusion
Battery
Process
Exhaust
Line
Aerosol
Photometer
Neutralizer
Diffusional Dryer
(Optional)
Particulate
Sample Line
Cyclone
(Optional)
Charge
Neutralizer Pressure
Balancing
Line
Recirculated
Clean Dilution
Air
Filter
Pump
Bleed
Figure 3. Optical and Diffusional Sizing System
-------
ro
u
« 3.0
o
a.
"o
CO
c
o
- 2.0
g
Si
or
UJ
o
5
o
uj 1.0
UJ
OC
BLOW SOOT
STOKE
CHARGE
TAP
[FURNACE
[OPERATION
• - PARTICLES WITH
DIAMETERS > 0.
O— PARTICLES WITH
DIAMETERS > 0.06 /zM
I
2:00
2:15
2:30
2:45
3:00
TIME
3:15
3:30 3:45 4:00
Figure 4. Inlet condensation nuclei counter data (with diffusion
batteries) through a typical set of furnace operations.
-------
11.2
m
E
—
o
o
°- 8.4
H-
o
in
1 7-0
z 5.6
o
4.2
O
I 2.8
1.4
BLOW SOOT
STOKE
CHARGE
TAP
-0.3-0.5uM
0-0.5-0.7yM
D
-0.7- I 3
2:00 2:15
2:30 2:45 3:OO
TIME
3:15
3:30
[FURNACE
(OPERATION
3:45 4:00
Figure 5. Inlet optical particle counter data through a typical
set of furnace operations.
-------
cycle. Figure 5 shows data from the particle
counter over the same time span. It is evident
from Figures 4 and 5 that large variations in the
particulate concentration and size distribution occur,
and that these variations can generally be traced
directly to one of the major furnace operations.
The accuracy of the fractional efficiency results
were thus limited by the degree to which appropriate
inlet and outlet time averages could be obtained.
Figure 6 shows typical averaged inlet and outlet
size distributions as obtained by optical and
diffusional methods over approximately one furnace
cycle. Figure 9 shows the fractional efficiencies
calculated from these data together with results
from the inpactor measurements. (In Figure 9, the
impactor data is presented using particle diameters
based on particle densities of 4.5 grams/cm3.)
Inertial sizing was accomplished using Brink Cascade
Impactors for inlet measurements and Andersen Impactors
for outlet measurements. Sampling was done at near
isokinetic rates. Errors due to deviations from
isokinetic sampling should be of little consequence
for particles having aerodynamic diameters smaller
than 5 ym. Because of the relatively small duct
dimensions and the relatively fine particulate being
sampled, single point sampling was used. The inlet
impactor runs were made using extractive sampling
with the impactors operated in an oven at a tempera-
ture of 408°K (275°F). The outlet impactor samples
12
-------
107
I06
o
at
JB
u
"r io5
o
Q.
g
<
cr
t-
IO3
10'
INLET
0.01
O.I 10
PARTICLE DIAMETER,
10.0
Figure 6. Average inlet and outlet size distributions
on a cumulative concentration basis.
13
-------
were obtained in-situ with the impactors heated to
about 22°K (40°F) above flue gas temperature to
insure that no condensation took place within the
impactor. Such condensation might cause operational
difficulties or lead to incorrect sizing.
Because of the wide disparity in the inlet and
outlet mass loadings (inlet ^ 500-3800 mg/DSCM
(0.220-1.660 grains/DSCF) and outlet ^ 10 mg/DSCM
(.005 grains/DSCF), complete simultaneity in the
inlet and outlet sampling was not possible. Out-
let samples were generally of about 8 hours duration
while inlet samples were of about 5 minutes duration.
Because of the low outlet loading and the consequent
length of the outlet sampling time, it was found to
be impractical to attempt to isolate a single
furnace cycle; however, an attempt was made to
have all outlet samples cover an integral number
of furnace cycles. Because the inlet sampling could
not correspond directly with the outlet sampling,
an average inlet mass loading for one complete
furnace cycle was synthesized for each size interval
covered by the inlet impaction stages from a total
of 30 runs made over the four-day period of June 25-28,
The sizes reported here for the inertial data are
given in two forms, "aerodynamic" and "physical"
diameters. The "physical" diameters are based on an
assumed particle density of 4.5 gm/cm3. If the true
particle densities are lower than this value, the
14
-------
sizes as given should be increased by a factor equal
to the square root of ratio of the assumed density to
true density. Aerodynamic diameters are diameters
based on a particle density of 1 gm/cm3. The impactor
data are summarized in Tables I and II. Figure 7 shows
the averaged inlet mass size distribution on a cumulative
percentage basis for both aerodynamic and physical
sizes. The fractional efficiencies as calculated
from these data are shown in Figure 8 on an aerodynamic
diameter basis and in Figure 9 on a physical basis.
Because the scrubber water used in this application is
in a recirculating loop, a substantial buildup of
dissolved solids occurs in the water. Any evaporation
of scrubber droplets to sizes that will escape the
cyclonic mist eliminator will contribute to the exit
particulate, perhaps to a substantial degree. During
the tests described in the previous sections of this
report, the dissolved solids content of the scrubber
water was about 750 ppm. At this solids concentration, a
1% loss of scrubber water from the mist eliminator would
result in an exit particulate loading of approximately
6 mg/M3 (or about .003 grains/ft3). In an attempt to
determine the extent of the actual contribution of
evaporative residues from the scrubber water to the exit
particulate loading, two outlet impactor runs were made
on November 26, 1974. For these runs the scrubber was
operated in a single pass water usage mode with water
having a dissolved solids content of about 230 ppm. Exit
particulate loadings as functions of particle size for
this second test are included in Table II. Although
15
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TABLE I
SCRUBBER INLET LOADING BY SIZE INTERVAL
Date
6/25
6/26
cn
6/27
6/28
Time
09:05*
11:16*
12:24*
14:59
15:25
16:52
18:00
09:37
11:10
11:50
12:05
14:20
15:26
16:25
17:15
10:07
10:40
11:38
13:09
14:18
15:02
09:09
10:24
11:02
12:11
13:15
14:29
15:02
16:16
WEIGHTED
PROCESS
AVERAGE
Furnace
Operations
Tap
Tap
Normal
Normal
Stoke
Tap
Charge
Normal/
Charge
Tap
Normal
Normal
Normal
Normal
Charge
Tap
Charge
Normal/
Stoke
Normal
Tap
Charge
Tap
Tap
Charge/
Stoke
Tap
Stoke
Normal/
Tap
Stoke
Tap
Charge
Particulate
Loading
mg/DSCM
1300
3760
474
1595
812
1500
841
617
1830
155
891
399
848
848
967
627
706
551
1600
868
1690
987
271
614
980
439
1670
1790
406
577
Dia., vim
p = 4.5 >5.9
Loading In Size Interval, mg/DSCM
3.4-5.9 2-3.4 1.4-2.0 0.7-1.4 0.50-0.70 0.2-0.5 <.2
79
373
130
1090
263
300
170
129
901
39.6
403
162
366
95.6
234
85.8
76.0
257
245
371
961
641
92.4
277
364
109
1144
1300
33.0
Dia. , ym >13
p = 1
199
18.9
318
19.9
105
205
252
165
42.8
129
<2
56.1
13.2
82.4
99.1
109
39.6
49.4
52.9
711
185
149
59.5
9.9
69.3
185
36.4
281
191
139
7.2-13
61.8
22.4
410
21.5
82.4
92.4
13.3
154
26.3
79.2
6.6
39.6
16.5
33.0
99.1
29.7
29.7
33.0
26.3
36.4
39.6
52.8
46.2
16.5
46.2
102
26.3
26.3
26.3
29.7
4.3-7.2
29.7
31.8
371
33.0
49.4
69.3
98.8
82.4
33.0
208
<2
33.0
22.9
19.8
33.0
43.0
33.0
12.7
16.5
29.7
16.5
89.0
19.8
13.3
19.8
139
16.5
13.3
36.4
16.5
3.0-4.3
27.5
89.5
480
69.3
49.4
26.3
350
43.9
33.0
76.0
<2
64.9
22.9
16.5
33.0
135
75.9
33.0
26.3
46.2
29.7
49.4
26.3
19.8
26.3
56.1
16.5
36.4
39.6
33.0
1.6-3.0
34.3
224.
583
41.2
54.9
33.0
162
30.2
65.9
241
<2
76.0
33.0
29.7
109
99.1
112
396
82.4
76.0
39.6
152
29.7
13.3
33.0
52.8
39.6
33.0
42.9
36.4
1.2-1.6
57.2
355.
323
101
49.4
69.3
238
124
132
.5-1.2
75.5
480.
901
57.7
116
52.8
89
71.4
155
99.1
29.7
89.0
62.7
75.9
254
237
125
42.9
16.5
323
46.2
139
89
26.3
69.3
52.8
99.1
46.2
76.0
36.4
99.1
79.2
129
65.9
224
125
79.2
125
62.7
72.5
129
142
99.1
76.0
79.2
72.6
29.7
95.6
89.0
79.2
82.4
91.5
*Measurements made on furnace §22 (identical to furnace #23, running same product).
-------
TABLE II
SCRUBBER OUTLET LOADING BY SIZE INTERVAL
Loading In Size Interval, mg/DSCM
Date
6/26
6/26
6/27
6/27
6/28
6/28
11/26
Start Time
09:00
10:40
14:00
09:30
10:00
09:15
10:55
09:55
10:55
11:04
11:10
Dia. , jjm
End Time p = 4 . 5
10:00T
17:40
18:30
17:00
17:30
10:25T
17:50
10:25T
18:15
18:04
18:10
>7.5
.39
.41
.39
.46
.39
.32
.19
.53
5.2-7.5
.21
.25
.30
.25
.32
.32
.20
.48
3.2-5.2
.11
.34
.34
.32
.34
.30
.13
.37
2.2-3.2
.14
.25
.34
.27
.37
.32
.27
.41
1.5-2.2
.23
.30
.41
.32
.37
.32
.28
.39
.65-1.5
.34
.32
.50
.37
.55
.48
.62
1.15
.39-. 65
.50
.53
.69
.59
.64
.78
2.80
3.65
.27-. 39
.85
.76
1.01
.85
.92
1.14
J.63
4.73
<.27
14.9*
5.63
6.73
5.45
7.18
6.86
9.65
13.90
Dia., pm
p = 1.0 >15.8 11.1-15.8 6.9-11.1 4.9-6.9 3.2-4.9 1.5-3.2 .92-1.5 .67-.92 <.67
•Loading may be atypical as a result of a power outage at about 10:00 am. Impactor run may have
resumed before the scrubber had attained steady state operating condition.
Tinterrupted because of plant power outage.
-------
00
LJ
M
98
95
90
80
60
to
UJ
Q.
=>
2
U
40
20
10
O.I
O AERODYNAMIC DIAMETERS
+ DIAMETER BASED ON
PARTICLE DENSITY OF 4.5 GRAMS/cm3
1.0
PARTICLE DIAMETER,urn
10
Figure 7.
Average inlet size distribution on a cumulative
weight percentage basis.
-------
99.99
99.9
99.8
^ 99.5
r
K" 99
J
z 98
LU
95
90
u
«H 80
60 —
40 —
O.I
i.o
PARTICLE SIZE, AERODYNAMIC DIAMETER
10
Figure 8
Fractional efficiency of the Aronetics Wet Scrubber
calculated from the weighted averages of 30 inlet
(Brink) and 6 outlet (Andersen Mark II) Impactor
tests. Particle sizes are given as aerodynamic
diameters (density = 1 gm/cm3).
-------
I
+ IMPACTORS
D OPTICAL
O DIFFUSIONAL
.ft.
O.I
1.0
PARTICLE DIAMETER ,
Figure 9. Fractional efficiency of the Aronetics Scrubber
based on optical, diffusional, and impactor data,
IO.O
-------
the furnace product was nominally the same for the
November 26 tests as that during the previous tests,
the furnace raw material and product compositions
were somewhat different. (The various raw material and
product compositions are given in Appendix B.)
Plant personnel stated that the furnace was upset
on this test (November 26) and that as a result
of past experience they would expect the inlet
loading to the scrubber to be higher during these
tests than during the previous test series. Un-
fortunately, time and circumstances precluded inlet
measurements during this short second test period.
And as a further complication, the scrubber
manufacturer stated that a perforated inner liner of
the mist eliminator had become plugged in the interval
between the two sets of tests, resulting in a partial mal-
function of the mist eliminator. Because of the
combination of these various factors, it is
felt that this brief second test did not accomplish
the intended goal and that the data, although
of some interest, does not represent a valid
comparison of the effect of dissolved solids
in the scrubber inlet water on the exit loadings
of the system.
Mass train measurements were obtained by Guardian
Systems, Inc., Anniston, Alabama, under subcontract
to Southern Research Institute on June 28 and 29,
and the results of these measurements are shown in
Table III. The overall efficiencies, by mass, based
on these results are included in Table III.
21
-------
TABLE III
MASS TRAIN (METHOD 5) RESULTS
Position
Date
Test No.
Time Start
Duration, min.
Avg. Gas Temp, K
R
Moisture, Vol. %
Avg. Gas Velocity, M/sec
Sample Vol. at Stack
Conditions, M3
Sample Vol. at Dry
Std. Conditions, M3
Grams/ACM
Grams/DSCM
Grains/DSCF
Efficiency
Inlet
6-26-74
1
1045
180
894
1610
4.18
20.59
7.01
2.21
.117
.366
.160
Inlet
6-26-74
2
1504
180
894
1610
3.39
20.56
7.03
2.24
.181
.570
.249
Inlet
6-27-74
3
0915
180
894
1610
5.33
18.68
8.33
2.60
.174
.554
.242
Inlet
6-27-74
4
1302
180
894
1610
3.41
21.01
8.39
2.67
.130
.410
.179
Outlet
6-26-74
5
1047
360
334
601
22.87
5.05
10.06
6.88
.016
.023
.010
95.1
Outlet
6-27-74
6
0915
360
337
607
20.42
3.36
9.00
6.29
.011
.016
.007
96.7
-------
Appendices are included which contain summaries of
furnace and scrubber operations during the time
intervals over which data were obtained, and
cost-estimates for the operation of the scrubber.
23
-------
SECTION IV - APPENDICES
APPENDIX A
MANUFACTURERS DESCRIPTION OF THE ARONETICS
TWO-PHASE JET SCRUBBER
A pressurized, heated, liquid when passed through
a properly designed nozzle will produce a two-phase
mixture of vapor and liquid droplets that is an
excellent cleaning medium. The droplets can be
accelerated to extremely high velocity as a result
of the expansion force created by a portion of the
liquid being converted to vapor. The general con-
figuration of this type of scrubber is shown in
Figures Ala and Alb. The proper arrangement of components
allows a draft to be induced which eliminates or dras-
tically reduces fan power requirements. The two-phase
jet scrubber produces water droplet velocities
which vary with the temperature of the scrubbing fluid
as shown in Figure A2. It is Aronetic's experience
that jet velocities in the range of 1000 feet per
second are quite satisfactory for particulate removal
in the size range down to 0.10 microns. The velocity
in the region immediately downstream of the nozzle is
probably substantially supersonic since there is consid-
erable evidence that sonic velocity in a two-phase
mixture may be as low as 350 feet per second. However,
Aronetic's believes that inertial impaction is the
controlling mechanism in cleaning and that the existence,
or absence, of the shock phenomena associated with
supersonic flow is not an advantage in the cleaning
effectiveness. Thus, the velocity in feet per second
24
-------
Figure Ala. Generalized Two Phase Jet Scrubber Nozzle.
TWO-PHASE
JET NOZZLE
•HEAT EXCHANGER
.MIXING
SECTION
STACK
SEPARATOR
MAKE-UP
WATER
PUMP
HOT GAS
WASTE WATER
TREATMENT
Figure Alb. Generalized Two Phase Jet Scrubber System.
25
-------
cn
450
400
ft!
2
350
300
250
NOZZLE EFFICIENCY 90 PER CENT
200
400 600 800
WATER JET VELOCITY, ft/sec
1000
1200
1400
Figure A2. Variation of water droplet velocity from
Two Phase Jet Nozzle with water temperature,
-------
is the controlling parameter rather than the Mach
Number, or relationship of velocity to the local
speed of sound. The device operates at a very
low noise level. The sound frequency and level is
similar to that generated by a garden hose nozzle.
With respect to the draft producing capacity of this
type of scrubber system, it should be evident that
this is a pure momentum transfer mechanism; therefore,
the amount of draft is a function of the amount of
fluid passed through the nozzle and the degree to
which this fluid is accelerated. The velocity is a
function of initial water temperature, as shown in
the previous figure. The effect of water flow rate
on system pressure rise is shown in Figure A3 for
water at a temperature of 400°F. It should be empha-
sized that this is a rise in pressure across the scrubber
and should not be confused with the pressure drop which
is associated with the venturi type scrubber. In most
applications, the pressure rise produced by the two-phase
jet is sufficient to overcome the pressure drop in
other components of a complete system.
The most direct application of the two-phase scrubbing
system is in the control of emissions from processes
which generate high temperature gas, laden with
submicron particulate. Typical examples are the
various metallurgical furnaces and processes. Figure Alb
showed schematically the general arrangement of the
components as tested in this report. An economizer
type of heat exchanger is used to transfer thermal energy
from the high temperature process exhaust gas to
pressurized hot water which is delivered to the heat
27
-------
NJ
CD
8
7
6
(9
o" 5
I
Q
3
WATER TEMPERATURE—400° F
I . I I
8
12
16
20
PRESSURE RISE, inches of water
Figure A3. System pressure rise as a function of water
flowrate.
-------
exchanger by a pump. Water exiting the heat exchanger
is delivered directly to the nozzle in its liquid
state. For most applications, the water temperature
is approximately 400°F and the water pressure is
approximately 350 psi, or high enough to ensure that
the fluid remains in the liquid state until it has
passed the nozzle throat. A properly dimensioned
mixing section must be provided for intimate contact
between the accelerated water droplets and the
particle laden gas. The final component in the scrub-
bing system train is a separator which will remove
the dirty water droplets and allow the clean gas to
be discharged. Water drained from the separator
is passed to water treatment equipment which may be
used to remove substances scrubbed from the gas and
to prepare the scrubbing liquid for recycling. In
the present instance, the water is used for approxi-
mately three passes through the system before final
discharge.
If the process off-gas is at a temperature level
above 1200°F, an additional option becomes available
in the selection of components. The economizer type
of heat exchanger may still be used to deliver
heated water directly to the nozzle, or a steam boiler
may be used as an intermediate step in the heating of
water. If sufficient energy is contained in the gas,
it is possible that a quantity of steam may be produced
which is greater than the demands of the scrubber.
This steam is then available for other possible plant
applications. Other elements of the system remain
essentially the same with the exception of the addition
29
-------
of a method to transfer thermal energy from steam
to water. The choice between the steam boiler
and the economizer type of system for the very high
temperature gases is dictated by local conditions
at the site in question.
30
-------
APPENDIX B - FURNACE OPERATION AND PRODUCTION DATA
Raw Materials
Date/Time
6/25 12-8
8-4
4-12
6/26 12-8
8-4
4-12
6/27 12-8
8-4
4-12
6/28 12-8
8-4
4-12
11/26 12-8
8-4
4-12
ORE
kg
Ibs.
25720
56700
31840
70200
22045
48600
20820
45900
35515
78300
29395
64800
19600
43200
42865
94500
26945
59400
30620
67500
28170
62100
17145
37800
28223
62217
28223
62217
28223
62217
COKE
kg
Ibs.
4285
9450
7890
17400
4900
10800
4900
10800
7890
7400
6895
15200
4500
9920
10450
23040
6285
13860
7145
15750
6570
14490
4770
10520
7742
17067
7742
17067
7742
17066
REMELT
Eg
Ibs.
3810
8400
4715
10400
3265
7200
3810
8400
5260
11600
8435
18600
2905
6400
6350
14000
3990
8800
4535
10000
4175
9200
2540
5600
4355
9600
5443
12000
3085
6800
GRAVEL
kg
Ibs.
1525
3360
1890
4160
1305
2880
1525
3360
2105
4640
1740
3840
1160
2560
2540
5600
1795
3960
2040
4500
1880
4140
1145
2520
980
2160
980
2160
980
2160
Product
Kg
Ibs.
7260
16000
8030
17700
4620
10190
11195
24680
9895
21810
7260
16010
11045
24350
9680
21340
10505
23160
8295
18290
21005
46310
None
10584
23333
10584
23333
10584
23334
Ferrochrome
Product Analysis
Chrome Silicon Carbon
70.3
71.0
70.3
70.4
70.3
70.4
70.7
68.5
69.0
70.7
69.9
.71
.44
.57
.48
.43
.87
.71
.89
.80
.89
1.06
65.7 2.37
66.7 1.71
64.6 2.49
7.0
7.1
7.6
7.1
6.8
7.0
6.9
6.2
6.9
6.7
6.8
6.7
7.0
6.6
Furnace
Load
KW
7680
7740
7380
7300
7920
6660
7560
7380
7200
7380
7330
6988
7377
7377
7377
-------
APPENDIX C - SCRUBBER OPERATING PARAMETERS
25th
Daily
Average
Water Flow
(1/min)
1200
1230
1300
1330
1400
1430
1500
1530
1600
1630
204.4
174.3
147.8
166.8
185.7
176.2
182.8
187.4
164.7
176.0
Water Inlet
Temp.
176.4 + 15.0
316.3
316.3
316.3
316.3
316.3
316.3
316.3
316.3
316.3
316.3
316.3
Water Exit
Temp.
469.1
488.6
488.6
491.3
494.1
488.6
496.9
496.9
494.1
494.1
490.2 + 8.4
Air Inlet
Temp.
860.8
.1
.1
844.
844.
871.9
877.4
849.7
888.6
883.0
849.7
877.4
Air Exit1
Temp.
377.4
374.7
371.9
374.7
380.2
377.4
383.0
383.0
377.4
377.4
Air Flow
(Kg/min)
250.9
248.2
209.1
227.7
257.7
249.5
253.6
263.2
240.9
243.2
864.7 + 17.2 377.4 + 3.3 244.5
OJ
to
26th
0900
0930
1000
1030
1100
1130
1200
1230
1300
1330
1400
1430
1500
1530
1600
1630
1700
1730
1800
1830
202.5
174.1
181.7
170.3
182.8
193.0
196.8
179.8
160.1
168.4
174.9
172.2
196.8
168.4
155.2
151.4
159.0
136.3
138.2
159.0
Daily
Average
171.1 + 18.9
310.8
310.8
310.8
310.8
310.8
310.8
310.8
308.0
308.0
308.0
308.0
308.0
308.0
308.0
308.0
308.0
308.0
308.0
308.0
308.0
309.0 + 1.1
466.3
458.0
471.9
485.8
499.
499.
499.
.7
.7
.7
498.0
494.1
499.7
499.7
498.0
502.4
502.4
494.1
499.7
502.4
502.4
502.4
485.8
493.0 + 13.3
838.6
827.4
858.0
888.6
880.2
896.9
896.9
877.4
885.8
860.8
863.6
880.2
910.8
871.9
844.1
866.3
866.3
844.1
844.1
855.2
867.9 + 22.0
377.4
360.8
366.3
369.1
377.4
383.0
388.6
385.8
377.4
377.4
380.2
377.4
385.8
377.4
371.9
369.1
374.7
366.3
366.3
358.0
375.2 + 7.2
266.
214.
232.
223.
267.
276.
285.
270.
256.
260.
270.
253.
284.
258.
238.
227.
245.
216.
219.
221.
^
1}
Not Sampling
249.5
Heat exchanger exit.
-------
Water Flow
(I/rain)
Water Inlet
Temp.
Hater Exit
Temp.
°
Air Inlet
Temp.
°
Air Exit
Temp.
Air Flow
(Kg/mm)
U)
27th
0900
0930
1000
1030
1100
1130
1200
1230
1300
1330
1400
1430
1500
1530
1600
1630
1700
1730
1800
1830
Dally
Average
212.0
162.8
159.0
155.2
168.4
166.5
174.1
187.4
179.8
173.0
168.4
170.3
179.8
162.8
174.1
174.1
172.2
173.0 + 11.4
319.1
319.1
321.9
321.9
321.9
321.9
319.1
319.1
316.3
316.3
313.6
313.6
313.6
310.8
310.8
310.8
310.8
316.3 + 4.4
488.6
499.7
505.2
505.2
505.2
499.7
502.4
502.4
502.4
503.6
502.4
505.2
499.6
502.4
502.4
500.8
499.7
501.3 + 3.9
877.
866.
844.
849.
888.
838.
844.
877.
866.
866.3
866.3
871.9
877.5
863.6
877.4
888.6
883.0
408.0
391.3
388.6
388.6
396.9
391.3
394.1
396.9
396.9
391.3
392.4
388.6
391.3
385.8
385.8
383.0
385.8
281.8
241.4
249.5
240.9
245.0
258.2
276.8
278.6
278.2
265.9
261.8
263.6
268.6
254.5
264.5
255.5
255.0
869.1 + 17.8 391.3 + 6.1
260.5
28th
0900
0930
1000
1030
1100
1130
1200
1230
1300
1330
1400
1430
1500
1530
1600
1630
1700
1730
1800
1830
159.0
159.0
172.2
155.2
162.8
151.4
153.3
159.0
170.3
155.2
166.5
162.8
151.4
151.4
157.1
151.4
143.8
155.2
174.1
—
313.6
313.6
313.6
313.6
313.6
313.6
310.8
310.8
308.0
308.0
308.0
308.0
308.0
308.0
308.0
305.2
305.2
305.2
305.2
494.1
499.7
438.6
474.7
499.7
499.7
499.7
499.7
500.8
499.7
498.0
499.
499.
499.
499.
499.
499.
499.
499.
871.9
855.2
710.8
885.8
869.1
860.8
855.2
871.9
880.2
866.3
869.1
877.4
860.8
871.9
866.3
871.9
855.2
855.2
874.7
371.9
374.7
360.8
360.8
377.4
374.7
377.4
374.7
377.4
374.7
374.7
374.7
371.9
366.3
371.9
369.1
366.3
366.3
366.3
224.1
240.0
240.01
185.9:
240.5
225.5
235.5
234.5
253.6
235.0
248.6
240.9
230.9
223.2
236.8
227.7
222.3
240.0
259.1
Not Sampling
Daily
Average
158.6 + 7.6
309.2 + 3.3
495.8 + 14.4
858.0 + 37.8 371.3 -f 5.0 236.4
-------
APPENDIX D
ESTIMATED OPERATING COSTS OF THE ARONETIC'S
TWO PHASE JET SCRUBBER SYSTEM
Data for these cost estimates were taken from Peters
and Timmerhans, Plant Design and Economics For Chemical
Engineers, 2nd edition, 1968, and are based on cost
data for the year 1967.
COST, $
Well Water 0.03 - 0.15/1000 gal.
River Water 0.02 - 0.06/1000 gal.
Fuel Oil 0.05 - 0.15/gal.
Electricity 0.02/KW-hour
Figure Dl shows estimated water use rates as furnished
by Aronetics for achieving 99% cleaning efficiency
for various particulate sizes. The use rate in the
tests described in this report was approximately
6 gallons/1000 SCF.
The operating costs described here are based on two
conditions - one in which the system energy is derived
solely from process waste heat and one for which fuel
oil supplies the energy. These figures are estimates
only and do not include such things as savings deriving
from the fact that the system provides its own draft
as well as that for the furnaces, consequently elimi-
nating I.D. and F.D. fans, blowers, etc.
34
-------
U)
Ul
UJ
K 3
tr
UJ
1
0.2
0.4
0.6
0.6
1.0
PARTICLE SIZE, microns
Figure Dl. Water use rate required for achieving 99% cleaning
efficiency for various particle sizes.
-------
The conditions of the tests with a net pressure rise
of 12^5 to 16 in. H20 were:
Water Usage 6 qal/1000 SCF
Cost of Electrical Power
for pumps, etc. .0017/1000 SCF*
Thermal Energy 17000 BTU/1000 SCF
Assuming nominal values for costs of 0.04/1000 gal. for
water, and 0.08 gal. for fuel oil, with the fuel oil
providing 150,000 BTU/gal., the operating cost per
thousand SCF are .00024 for water and .0017 for
electrical power for a total of .00194 when waste
heat is used to drive the system. Where waste heat
is not available for hot water production, adding
the fuel cost of .0089/1000 SCF results in an opera-
ting cost per 1000 SCF of 0.0107. The annual opera-
ting costs per SCFM are $1.016 in the waste heat
case and $5.59 for the case in which fuel must be
purchased (excluding electrical energy - these values
become 0.042 and 4.44, respectively.) For the purposes
of the preceding operating cost estimates, amortization
of capital costs were not included.
*Based on figures given in a .paper by H. Gardenier at
the APT/EPA 1974 Scrubber Symposium.
36
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1 REPORT NO
EPA-650/2-74-129
3 RECIPIENT'S ACCESSION NO.
4 TITLE AND SUBTITLE
Evaluation of Aronetics Two-Phase Jet Scrubber
6 REPORT DATE
December 1974
6. PERFORMING ORGANIZATION CODE
7 AUTHORIS)
8 PERFORMING ORGANIZATION REPORT NO,
Joseph D. McCain
SORI-EAS-75-022
9 PERFORMING OR8ANIZATION NAME AND ADDRESS
Southern Research Institute
2000 Ninth Avenue, South
Birmingham, Alabama 35205
10 PROGRAM ELEMENT NO.
1AB012; ROAP 21ADL-004
11 CONTRACT/GRANT NO
68-02-1480
12 SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
NERC-RTP, Control Systems Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVEI
Phase I, Final; 9/74-11/74
RED
14. SPONSORING AGENCV CODE
5 SUPPLEMENTARY NOTES
6 ABSTRACT
The report gives results of fractional and overall mass efficiency tests of
the Aronetics two-phase jet scrubber. The tests were performed on a full scale
scrubber used for controlling particulate emissions from a ferroalloy electric arc
furnace. Total flue gas particulate mass concentrations were determined at the inlet
and outlet of the scrubber by conventional (Method 5) techniques. Inlet and outlet
particulate concentrations as functions of size were determined on a mass basis using
cascade impactors for sizes of about 0.3-5 /urn, and on a number basis for sizes
smaller than about 1 jum using optical and diffvisional methods. The report includes
brief descriptions of the ferroalloy furnace process, the Aronetics scrubber,
economics of operating the scrubber, measurement methods for determining
fractional efficiency, a time history of the furnace particulate emissions, and
measured fractional efficiencies.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Air Pollution
Scrubbers
Jets
Evaluation
Tests
Electric Arc Furnaces
Ferroalloys
Measurement
Flue Gases
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Air Pollution Control
Stationary Sources
Aronetics
Two-Phase Jet Scrubber
Mass Efficiency
Particulate
13B, 11F
07A, 20F
20D, 21B
14B
DISTRIBUTION STATEMENT
19 SECURITY CLASS (This Report]
Unclassified
Unlimited
21 NO OF PAGES
43
20 SECURITY CLASS (Thispage)
Unclassified
22 PRICE
EPA Form 2220-1 (9-73)
37
------- |