Tennessee
Valley
Authority
United States
Environmental Protection
Agency
Office of Power
Power Research Staff
Chattanooga. Tennessee 37401
Office of Research and Development
Office of Energy. Minerals, and Industry
IERL. Research Triangle Park. NC 27711
EPA-600/7-76-021
October 1976
TVA'S 1-MW PILOT PLANT
VERTICAL DUCT MIST
ELIMINATION TESTING
Progress Report
Interagency
Energy-Environment
Research and Development
Program Report
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S.
Environmental Protection Agency, have been grouped into seven series.
These seven broad categories were established to facilitate further
development and application of environmental technology. Elimination
of traditional grouping was consciously planned to foster technology
transfer and a maximum interface in related fields. The seven series
are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7- Interagency Energy-Environment Research and Development
This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
RESEARCH AND DEVELOPMENT series. Reports in this series result from
the effort funded under the 17-agency Federal Energy/Environment
Research and Development Program. These studies relate to EPA's
mission to protect the public health and welfare from adverse effects
of pollutants associated with energy systems. The goal of the Program
is to assure the rapid development of domestic energy supplies in an
environmentally—compatible manner by providing the necessary
environmental data and control technology. Investigations include
analyses of the transport of energy-related pollutants and their health
and ecological effects; assessments of, and development of, control
technologies for energy systems; and integrated assessments of a wide
range of energy-related environmental issues.
This document is available to the public through the National Technical
Information Service, Springfield, Virginia 22161.
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PRS - 14
EPA-600/7-76-021
October 1976
TVA'S I-MW PILOT PLANT«
VERTICAL DUCT MIST ELIMINATION
TESTING -- PROGRESS REPORT
by
G.A. Hollinden, R. F. Robards, and N.D. Moore (TVA/Chattanooga)
T. M. Kelso and R. M. Cole (TVA/Muscle Shoals)
Tennessee Valley Authority
Power Research Staff
Chattanooga, Tennessee 37401
and
Office of Agricultural and Chemical Development
Muscle Shoals, Alabama 35660
Interagency Agreement No. EPA-IAG-D5-072I
Program Element No. EHB528
EPA Project Officer: John E. Williams
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, NC 27711
Prepared for:
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
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DISCLAIMER
This report has been prepared by the Tennessee Valley Authority and
reviewed by the U.S. Environmental Protection Agency and approved for
publication. Approval does not signify that the contents necessarily
reflect the views and policies of either agency, nor does mention of
trade names or commercial products constitute endorsement or
recommendation for use.
ii
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ABSTRACT
TVA has recently demonstrated washing techniques that maintain con-
tinuous mist eliminator performance for lime/limestone closed-loop
scrubbing systems at its 1-MW pilot plant at the Colbert power
plant. The systematic test program which developed these washing
techniques is reviewed for both the limestone and lime systems.
Continuous operation of the Chevron-type mist eliminator, positioned
horizontally in a vertical duct, in the limestone system was main-
tained (after extensive testing) by washing the bottom of the mist
eliminator intermittently with all the available clarified liquor
immediately followed by an allocated amount of the allowable makeup
water. The top of the mist eliminator was washed intermittently
with the remaining allocation of allowable makeup water. Contin-
uous mist eliminator performance in the lime system was maintained
by washing the bottom of the mist eliminator intermittently with
an allocated amount of allowable makeup water. The remainder of
the allocated makeup water was used to intermittently wash the top
of the mist eliminator.
iii
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CONTENTS
Page
Abstract iii
Figures v
Introduction 1
Summary and Conclusions 2
Work Completed ^
Future Work 22
Conversion Factors 23
iv
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FIGUKES
Humber Page
1 TCA Scrubber Flow Diagram k
2 Chevron Mist Eliminator 5
3 Mist Eliminator Test Module 6
h Top and Bottom Views of Mist Eliminator After 202
Hours of Operation (Test ME-10) 8
5 Top and Bottom Views of Mist Eliminator After 120
Hours of Operation (Test ME-ll) 9
6 Side and Bottom Views of Mist Eliminator After 96
Hours of Operation (Test ME-12) 10
7 Side and Bottom Views of Mist Eliminator After 8k
Hours of Operation (Test ME-13) 11
8 Top and Bottom Views of Mist Eliminator After 213
Hours of Operation (Test ME-1^) 13
9 Top and Bottom Views of Mist Eliminator After 500
Hours of Operation (Test ME-15) 13
10 Side, Top, and Bottom Views of Mist Eliminator
After 1000 Hours of Operation (Test ME-15) lU
11 Side View of Mist Eliminator After 13l»-
Hours of Operation (Test ME-17) 15
12 Side, Top, and Bottom Views of Mist Eliminator
After 560 Hours of Operation (Test ME-18) 17
13 Trends in Operating Data 18
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INTRODUCTION
TVA has operated the 1-MW wet lime/limestone pilot plant at the Colbert
Steam Plant since February 1971. Until recently, this pilot plant was
used primarily for testing limestone scrubbing with major attention
directed toward the full-scale 550-MW Widows Creek limestone scrubbing
system.
Results from this testing suggested utilizing a vertical mist eliminator
in a horizontal duct. This type of mist elimination design permits the
use of a separate wash system for the mist eliminator than that of the
scrubber. More recently, the pilot plant tests were designed to evaluate
similar methods for washing this type of mist eliminator without exceed-
ing the water balance of the closed-loop limestone wet scrubbing process.
The quantity of fresh water required for effective washing of the mist
eliminator on a once-through basis was four to five times the amount
required for makeup to the closed-loop slurry system. One such method
of maintaining continuous operation of the mist eliminator in the hori-
zontal duct while operating in a closed-loop slurry system is the use of
sodium carbonate in the recyclable mist eliminator wash system. This
additive increases the solubility of sulfates thus reducing the tendency
for scale formation. The additive method may not be applicable for
washing the mist eliminator in the vertical duct because of the difficulty
in separating the wash liquor from the scrubber liquor. Such separation
is necessary to avoid loss of sodium carbonate which would be prohibi-
tively expensive.
The major objective of the current study is to develop reliable closed-
loop mist eliminator washing techniques for lime/limestone systems where
the mist eliminator is positioned in the vertical duct. This report
covers the systematic operation of a Chevron-type mist eliminator leading
to its 1000 hour long-term run in the limestone mode and 560 hour run in
the lime mode.
1
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SUMMA.RY AND CONCLUSIONS
Pilot-plant tests have demonstrated washing methods that maintain
continuous mist eliminator performance. Continuous performance of
a horizontally mounted mist eliminator operating in the limestone
mode is difficult because the wash water required for proper
washing cannot be separated from the slurry system. Closed-loop
operation precludes using copious amounts of fresh water to main-
tain reliable mist eliminator performance since the allowable
makeup water rate is approximately 0.7 gpm or 0.2 gpm/ft of duct
area. The recommended wash rate is 5 gpm/ft . An intermittent
wash using additional sources of wash liquor had to be used.
Washing the mist eliminator intermittently in the limestone mode
with fresh makeup water was not successful. This may partly be
attributed to operating the limestone mode at a stoichiometry of
1.5. Operation at this stoichiometry increases the plugging poten-
tial with soft mud-like solids due to excess limestone in the
scrubbing slurry being entrained into the mist eliminator. The
accumulation was at such a rate that another liquid source was
needed to wash the mist eliminator. The clarified liquor to the
scrubber system was accumulated and used to wash the mist elimin-
ator along with the allowable amount of makeup water. Previous
testing has shown that washing the mist eliminator with a blend of
clarified liquor and makeup water results in chemical scaling and
plugging. This chemical scale occurs when the supersaturated
clarified liquor reacts with the remaining SOg in the flue gas,
thus, resulting in the deposition of calcium-sulfur salts on the
mist eliminator blades. Washing with clarified liquor followed by
makeup water was successful in removing the soft mud-like solids
and the calcium-sulfur salts from the mist eliminator. Continuous
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mist eliminator performance in the limestone mode was maintained
by washing the bottom of the mist eliminator intermittently with
all the available clarified liquor immediately follo'wed by an
allocated amount of the allowable makeup water. The top of the
mist eliminator was washed intermittently with the remaining
allocation of allowable makeup water.
Washing the mist eliminator intermittently in the lime mode with
fresh makeup water was successful. The lime system operated at a
stoichiometry of 1.0 which alleviated having excess alkali material
in the scrubbing slurry being entrained into the mist eliminator.
Continuous mist eliminator performance in the lime mode was main-
tained by washing the bottom of the mist eliminator intermittently
with an allocated amount of allowable makeup water. The remainder
of the allocated makeup water was used to wash the top of the mist
eliminator intermittently. Proper implimentation of the available
wash water and the wash frequency is the key contributor in main-
taining continuous mist eliminator performance. These results do
not say that all mist eliminator problems are solved, but the pro-
gress in that direction is certainly encouraging.
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WOEK COMPLETED
The pilot plant operated on a closed-loop basis. The only liquor
purged from the system was that contained in the discarded spent
solids (filter cake). The quantity of liquor amounted to about
lUo pounds per hour when the filter cake contained 60 to 65 percent
solids. Figure 1 shows a flow diagram of the pilot plant, while
operating in the limestone mode. Fredonia limestone (75% - 200
mesh) was fed to the system at a rate sufficient to maintain a
Ca:S02 mole ratio of 1.5 based on the concentration of S0_ in the
inlet flue gas. Scrubbing slurry containing 15 percent suspended
solids and 1.3 percent dissolved solids was recirculated to the
venturi and absorber at a liquid-to-gas ratio (L/G) of 10 and 50
gallons per 1000 cubic feet, respectively. The scrubber contained
two stages (each 12 in deep) of 10-gram thermoplastic rubber (TPR)
spheres manufactured by Moldcraft.
REHEAT SYSTEM
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FIGURE 2
CHEVRON MIST ELIMINATOR
The Turbulent Contact Absorber (TCA) operated at a superficial
velocity of 12.6 to 13.8 feet per second. The concentration of
SOp in the inlet flue gas varied from about 1600 to 2700 ppm. The
SOp removal averaged 72 percent. This low SOg removal is attri-
buted to the absorber inlet spray header being lowered (approxi-
mately 15 ft) to just beneath the third grid so that the mist
eliminator could be installed between the third and fifth grids.
The particulate loading in the inlet and outlet averaged k.5 and
0.02 grains per standard cubic foot, respectively. The pressure
drop across the venturi and TCA-type absorber (containing 3 grids
and 2 stages of the TPR spheres) averaged 9 and 7 inches of water,
respectively. The mist eliminator tested was the three-pass, 90-
degree bend, Chevron-type with 1-|- in spacings as shown in Figure
2. The mist eliminator was placed in the horizontal position in
the vertical absorber tower. Figure 3 shows the test module for
viewing the operation of the mist eliminator.
The initial run was designed to observe drainage and mist entrain-
ment from the mist eliminator washes at superficial gas velocities
of 5, 7.5, 10. 12.6, and l6 ft/s using only air and water. Proper
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drainage of the mist eliminator occurred at 12.6 ft/s—the planned
operating velocity.
The operation and washing conditions for all runs with the mist
eliminator positioned in the vertical tower are summarized in
Table 1.
Run ME-10 began on July 29, 19755 using flue gas and limestone
slurry with an initial pressure drop across the mist eliminator
of 0.2 inch HO. The mist eliminator was washed intermittently
with only fresh makeup water--0.7 gal/min or 336 gal/shift. Two-
thirds of this water was used to wash the bottom of the mist
eliminator at one-hour intervals. The remainder of the water
washed the top of the mist eliminator every two hours. The
pressure drop gradually increased and leveled off several times
FIGURE 3
MIST ELIMINATOR TEST MODULE
t
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Top Wash
TABLE 1
SUMMARY OF MIST ELIMINATOR OPERATIONS
Bottom Wash
Duration AP Pressure Rate Duration
Run of Test (in. H^O) (psi) (gpm) (min)
ME-9 12 h
ME-10 202 h 0.2—1.5 10 8 3.5
ME-ll 120 h 0.1—0.5 10 8.2 1.6
ME-12 96 h 0.1—0.2 10 8.2 1.6
ME-13 8U h 0.1— 0. U 10 8.2 1.6
ME-ll* 213 h 0.1—0.2 10 8.2 1.6
Interval Type Pressure
(h) Wash (psi)
2 FW 20
2 FW 20
2 FW 20
20
2 FW 20
20
2 FW 20
20
Rate
. (gjom) _
11.7
11.7
11.7
11.7
11.1*
11.1*
11.1*
11.1*
Duration
(min)
2.1*
1.5
1.8
1.53
1.8
1.53
1.55
Interval
1
0.5
0.5
0.5
0.5
0.5
0.5
0.5
Type Total ME Wai
Wash (gal/shift)
FW
FW
CL*
FW
CL*
FW
CL*
FW
337
333
337
339
328
332
985
335
jh
Comments
Air/water test.
Top two passes clean.
Lower lip plugged with mud-like deposits
Top two pases clean. Lower lip
plugged with mud-like deposits
with indications of scale in mud.
Top two passes clean. Bottom center
plugged probably due to spray pattern.
Used 2 nozzles at 5.7 gpm. Suddenly
started plugging. Upset unknown.
Similar to ME-13. May begin having
problems maintaining solids
ME-15 1000 h 0.1—0.1 10 8.2 1.6
ME-16 166 h 0.1—0.2 10 8.2
1.6
ME-17 131* h 0.1—0.2 10 8.2 1.6
ME-18 560 h 0.1 — 0.1 10 8.2 1.6
FW: Fresh makeup water 0.7 gpm: 336 gal/shift
CL: Clarified liquor
SL: Slurry
20
20
15
20
15
20
11.1*
11.1*
6.0
ll.U
6.0
11.1*
2.7
0.78
2.7
0.78
2.7
0.78
0.25
0.25
0.25
0.25
0.25
0.25
CL*
FW
SL*
Fit
SL*
FW
985
338
518
338
518
338
FW
20
U.I*
0.65
0.25
289
concentration. May have been
stopped premature—one small area
causing pluggage—rest clean with
little mud on bottom edges
(always there).
Nozzles were raised to cover a missed
area 9-9-75. ME momentarily removed
after 500 hours for photographing.
Units 3,1*, and 5 off-line—pilot
plant shut down 10-6 to 10-8. ME
remained clean through 1,000 hours.
Second pass plugging. Nozzles plugging
and cleaned by blast of air (30 psi)--
may have helped clean ME.
Nozzles eroded.
Separate and rotating slurry header.
Plugging in second pass.
Lime mode: 0.6 gpm makeup--288 gal/shift
ME remained clean while using only
fresh makeup water
•Followed imnediated with fresh water wash
-------
•f *
7,'.
FIGURE 4
TOP AND BOTTOM VIEWS OF MIST ELIMINATOR
AFTER 202 HOURS OF OPERATION (TEST ME-10)
before the run was terminated at a pressure drop of 1.5 inches
HO. The run lasted approximately 200 hours. During this run,
the top two passes remained clean indicating a sufficient, if not
excessive, top wash. The bottom pass was plugged with soft, mud-
like deposits mainly on the lower lip of the mist eliminator.
Figure k shows the accumulation of this material on the mist
eliminator. It was decided that a pressure drop of 1.5 inches
HO was excessive as a terminating point--no stopping point had
been determined up to this point. A more realistic termination
point of 0.5-inch HO was selected for the next run.
Run ME-11 began on August 6, 1975, with an initial pressure drop
of 0.1 inch HpO. Since the top passes remained clean during the
previous run, half of the makeup water used to wash these passes
was added to the bottom wash. The frequency of the bottom wash
was reduced to every 30 minutes. The pressure drop rose slowly
until reaching the termination point after about 120 hours.
Figure 5 shows the appearance of the mist eliminator at the end of
this run. Its appearance was similar to that in the previous run.
The lower lip was partially plugged with soft solids, but there
:
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FIGURE 5
TOP AND BOTTOM VIEWS OF MIST ELIMINATOR
AFTER 120 HOURS OF OPERATION (TEST ME-II)
were indications of scale deposits in this mud. The scale forma-
tion was probably due to the remaining S0? in the flue gas reacting
with soft solids already attached to the mist eliminator thus
forming the hard calcium sulfate salts. From experience at
Colbert and Shawnee and from calculations on pressure drop versus
percent pluggage of the mist eliminator, a pressure drop increase
of 0.1-in HpO when starting at 0.1-in HpO gives a 30 percent
pluggage. Therefore, a new termination point of 0.2-in HpO was
chosen for all subsequent runs.
Run ME-12 began on August 10, 1975, with an initial pressure drop
of 0.1-in HpO. Since the top two passes remained clean during the
previous run and reducing more water from this wash to add to the
bottom wash would be an almost insignificant addition, some of the
available clarified liquor was used to supplement the bottom wash.
Previous mist eliminator tests, prior to this project, had indi-
cated that washing with a mixture of clarified liquor--saturated
with CaSOi—and fresh water would result in scale formation on
the blades. With this experience, it was decided to use clarified
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•
FIGURE 6
SIDE AND BOTTOM VIEWS OF MIST ELIMINATOR
AFTER 96 HOURS OF OPERATION (TEST ME-12)
liquor as the bottom wash and to immediately follow this wash with
the fresh makeup water. Such operation reduces the possibility of
any clarified liquor remaining on the blades for any length of
time and becoming supersaturated with CaSOi and cause scaling to
occur. The pressure drop during this run ronained fairly constant
for approximately 100 hours when the center of the lower lip be-
gan plugging thus causing termination of the run. Figure 6 shows
the plugged area that caused the increase in pressure drop. The
small area that had accumulated the soft deposits was believed to
be caused by an uneven distribution of the wash and additional
nozzles were recommended for subsequent runs.
Run ME-13 began on August 19, 19755 with an initial pressure drop
of 0.1-in HO. Two nozzles were used for the bottom wash with a
total wash similar to the previous runs using one nozzle. The
duration of the bottom wash was adjusted to account for the
difference while the top wash remained the same. The pressure
drop remained constant for approximately 100 hours when it
suddenly rose to O.U-in HO. The reason for this increase is not
certain. Figure 7 shows the appearance of the mist eliminator at
10
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FIGURE 7
SIDE AND BOTTOM VIEWS OF MIST ELIMINATOR
AFTER 84 HOURS OF OPERATION (TEST ME-13)
the end of this run.
Run ME-lU began on August 23, 1975? with an initial pressure drop
of 0.1-in H_0. It was decided to increase the clarified liquor
wash to the maximum available--approximately 100 gal/shift or
three times that used previously. The fresh makeup water wash
immediately followed this clarified liquor wash. There was some
concern about maintaining adequate solids concentration with the
addition of this clarified liquor. However, the concentrations
were held fairly close to design conditions. After approximately
200 hours of operation, the run was terminated after reaching a
pressure drop of 0.2-in H?0. This termination may have been pre-
mature because of the variability of the pressure drop readings.
Figure 8 shows the accumulation of mud on the mist eliminator at
the end of this run.
Run ME-15 began on September 1, 1975, with an initial pressure
drop of 0.1-in H_0. The only difference between this run and the
11
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previous run is the frequency of the bottom wash was changed from
every 30 minutes to every 15 minutes. The washing duration was
therefore adjusted to maintain the same total wash on the bottom.
The pressure drop of 0.1-in HO was maintained for 1000 hours.
The mist eliminator was momentarily removed after 500 hours for
photographing. Figure 9 shows the appearance of the mist elimin-
ator at that time. Figure 10 shows the appearance of the mist
eliminator after completion of the long-term run.
Run ME-16 began on October Ik, 1975, to test the effect of washing
the mist eliminator with absorber slurry and fresh makeup water.
An initial pressure drop across the mist eliminator was 0.1-in
HO. The bottom of the mist eliminator was washed at 15-min
intervals with absorber slurry followed immediately by the major-
ity of the fresh makeup water. The top wash remained the same.
A buildup of soft mud-like solids occurred in the second pass of
the mist eliminator. More than likely, this buildup was caused
by an accumulation of slurry solids that were carried into the
mist eliminator during the slurry wash sequence. The same header
was used for the slurry wash as the makeup water wash. High-
pressure air was used frequently to dislodge slurry solids from
the two spray nozzles. This resulted in a portion of the solids
which originally accumulated in the second pass to be blown into
the third pass where they were removed by the top wash. The net
effect of using high-pressure air to aid in cleaning the mist
eliminator is uncertain. After 166 hours of operation, the
pressure drop reached 0.2-in HO and the run was terminated.
Run ME-17 began on October 21, 1975» using the same washing
techniques as ME-16 with the exception that a separate spray
header with larger nozzles was used for the slurry wash. These
nozzles plugged with slurry solids and high-pressure air was un-
successful to unplug these nozzles because a sufficient back
pressure could not be maintained. The solids accumulated in the
second pass of the mist eliminator at a faster rate than the
12
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• VI
FIGURE 8
TOP AND BOTTOM VIEWS OF MIST ELIMINATOR
AFTER 213 HOURS OF OPERATION (TEST ME-14)
FIGURE 9
TOP AND BOTTOM VIEWS OF MIST ELIMINATOR
AFTER 500 HOURS OF OPERATION (TEST ME-15)
13
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FIGURE 10
SIDE, TOP, AND BOTTOM VIEWS OF MIST ELIMINATOR
AFTER 1000 HOURS OF OPERATION (TEST ME-15)
11*
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FIGURE II
SIDE VIEW OF MIST ELIMINATOR
AFTER 134 HOURS OF OPERATION (TEST ME-17)
previous run. This may be due to the elimination of high-pressure
air hitting the mist eliminator. The run was terminated after
13^- hours of operation when the pressure drop reached 0.2-in H?0.
Figure 11 shows the spray headers and the mud deposits in the
second pass at the end of the run.
Run ME-18 began on November 29, 1975? using lime as the absorbent
in the scrubber. The chemistry of the absorption of SO is
different in the lime mode which results in higher utilization of
the absorbent and, therefore, a reduction in the amount of water
removed with the sludge. The makeup water requirement for the
lime mode is approximately 0.6 gal/min/MW as compared to 0.7
gal/min/MW for limestone. This reduces the quantity of water
available to wash the mist eliminator. As a base case the mist
eliminator was washed intermittently with fresh makeup water only.
The top was washed every 2 hours and the bottom every 15 minutes.
The pressure drop across the mist eliminator remained 0.1-in HO
15
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through 560 hours of operation. At that time, the pilot plant
was shut down for the Christmas holidays. Figure 12 shows the
appearance of the mist eliminator at the end of the lime run.
This run completed the mist eliminator tests in the vertical duct.
Trends in operating data for all runs are graphically displayed
in Figure 13.
16
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FIGURE 12
SIDE, TOP, AND BOTTOM VIEWS OF MIST ELIMINATOR
AFTER 560 HOURS OF OPERATION (TEST ME-18)
17
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SBtf
sill
Jfi
a!"
to>-
13-
U -
CALS.I).
n ii e o
ME-II i
I I • I
H B W IT
it 20 a
T40UTOFSERVKC-
t I ' '
Z72t»903l3I39 J4 M
ME-K J
FIGURE 13
TRENDS IN OPERATING DATA
18
-------
.OS
-------
a.
— oe
Ulk
o
S .06
S -04
-J 1 1
J L
90-
80-
70-
60 -
50.
J 1 1 I I I
-1 1 1 I I I
J I I
S* 90
CLEAR UOUOR RETURN
ABSORBER SLURRY
i i i
I I i I I
i •**
!? *
3. J5
h JO
I I I i I I
§ e 20
J in
1.5
i i i i
I I I I I I
-UNIT 3 OUT OF SERVICE
I i i i i
i i I 1 1 L
i i i i i i i
I I 1 1 1 1
(OCT"
23456789K>lll2l3
WI5l6r7l8l92O
ME-16 -
2l2223242526
ME-17 - ^
FIGURE 13 (CONT.)
TRENDS IN OPERATING DATA
20
-------
20 -
a M
If .0*1
"r
60-
120 •
110-
100-
90 -
so -
70 -
60 -
50 —
CLEAR LIQUOR RETURN
ABSORBER FEO
83 075
1 05
I I t
I I I
(11-24-79)
J ME-17—»
9 10 II 12 13 H 13 B 17 18
21 22 23 24
27 28 29
(I2-21-T5I
ME-16
FIGURE 13 (CONT.)
TRENDS IN OPERATING DATA
21
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FUTURE WORK
The remaining task scheduled for this project is the development
of a high velocity scrubber and mist eliminator combination. A
modified TCA scrubber, using lime as the absorbing media, will be
operated at a gas velocity of 16 ft/sec. The Chevron mist elimin-
ator will be positioned horizontally in the vertical duct and will
initially be washed similarly to the previous lime runs.
22
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CONVERSION FACTORS
The Environmental Protection Agency policy is to express all
measurements in metric units. Implementing this practice will
result in undue lack of clarity. The following conversion factors
are provided to convert the nonmetric units to the International
System of Units (Si).
To Convert From
Inches HpO
P
Pound/inch (psi)
Pound (Ib)
Gallon/minute (gpm)
Gallon (gal)
Foot/second (ft/sec)
Foot2 (ft2)
Foot3 (ft3)
To
Millimeter Mercury (mm Hg)
Atmosphere (atm)
Kilogram (kg)
Liter/minute (1/min)
Liter (1)
Meter/second (m/sec)
Meter2 (m2)
Meter3 (m3)
Multiply By
1.868 x 10°
6.805 x 10"2
It.536 x 10"1
3.785 x 10°
3.785 x 10
3.CA-8 x 10
9.290 x 10
-1
-2
Degree Fahrenheit ( F) Degree Centigrade ( C)
2.832 x 10"2
t = (t, - 32)/1.8
23
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/7-76-021
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
TVA's 1-MW Pilot Plant: Vertical Duct Mist Elimination
Testing—Progress Report
5. REPORT DATE
October 1976
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
G. A. Hollinden, R. F. Retards, N0 D, Moore
(TVA-Chatt), T. M. Kelso, and R. M. Cole (TVA-MShoals)
8. PERFORMING ORGANIZATION REPORT NO.
PRS-lU
9. PERFORMING ORGANIZATION NAME AND ADDRESS
TVA, Power Research Staff, Chattanooga, TN 37^01
and TVA, Office of Agricultural and Chemical Development,
Muscle Shoals, AL 35660
10. PROGRAM ELEMENT NO.
EHB528
11. CONTRACT/GRANT NO.
EPA-IAG-D5-0721
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Progress Report: 6-12/75
14. SPONSORING AGENCY CODE
EPA-ORD
is. SUPPLEMENTARY NOTES EPA prcg ect officer for this report is John E. Williams, Mail
Drop 61, Ext 2915.
16. ABSTRACT
The report reviews (for-both the lime and limestone systems) the systematic test
program which developed recent TVA-demonstrated washing techniques that maintain
continuous mist eliminator performance for lime/limestone closed-loop scrubbing systems
at TVA's 1-MW pilot plant at the Colbert power plant. Continuous operation of the
chevron-type mist eliminator, positioned horizontally in a vertical duct, in the
limestone system was maintained (after extensive testing) by washing the bottom of the
mist eliminator intermittently with all the available clarified liquor, immediately
followed by an allocated amount of the allowable makeup water. The top of the mist
eliminator was washed intermittently with the remaining allocation of allowable
makeup water. Continuous mist eliminator performance in the lime system was maintained
by washing the bottom of the mist eliminator intermittently with an allocated amount
of allowable makeup water. The remainder of the allocated makeup water was used to
wash the top of the mist eliminator intermittently.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Air Pollution
Scrubbers
Washing
Calcium Oxides
Limestone
Air Pollution Control
Stationary Sources
Mist Eliminators
13B
07A
13H
07B
18. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (ThisReport}
Unclassified
21. NO. OF PAGES
29-
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
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