xvEPA
United States Industrial Environmental Research EPA-600/7-79-118
Environmental Protection Laboratory May 1979
Agency Research Triangle Park NC 27711
In-stack Plume Opacity
from Electrostatic
Precipitator/Scrubber
System at Harrington
Unit 1
Interagency
Energy/Environment
R&D Program Report
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EPA-600/7-79-118
May 1979
In-stack Plume Opacity from Electrostatic
Precipitator/Scrubber System at
Harrington Unit 1
by
Leslie E. Sparks
U. S. Environmental Protection Agency
Industrial Environmental Research Laboratory
Paniculate Technology Branch
Research Triangle Park, N. C. 27711
Program Element No. EHE624A
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
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ABSTRACT
Results of theoretical modeling of particulate emission and
in-stack plume opacity for the electrostatic precipitator (ESP)/scrubber
system at Southwestern Public Service Company's Harrington Unit 1 are
presented. The theoretical results of an emission rate of 17.8 ng/J and
opacity of 35% are in good agreement with data from compliance testing
of the unit. The calculations indicate that 20% opacity can be achieved
(1) by increasing specific collector area (SCA) of the ESP by 25% and
leaving the scrubber pressure drop alone, (2) by increasing scrubber
pressure drop by a factor of 4 and leaving the ESP alone, (3) by replacing
the existing marble bed scrubber with a venturi scrubber, increasing
the pressure drop by 20%, and leaving the ESP alone, or (4) by doubling
the SCA of the ESP and removing the scrubber. Calculations showing the
impact of high in-stack opacity on the downwind appearance of plume are
also included.
n
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TABLE OF CONTENTS
Page
Abstract ii
List of Figures iv
List of Tables iv
Nomenclature v
Acknowledgements vi
Conclusions 1
Recommendations 1
Introduction 2
Possible Reasons for Excessive Opacity 3
Description of the System 4
Particle Si2e Data 4
Models 4
ESP Model 4
Scrubber Model 11
Opacity Model 11
Modeling Technique 12
Steps Necessary to Achieve 20% Opacity 14
Opacity if a Venturi Scrubber Were Used 14
Accuracy of the Calculations 18
Possible Environmental Impact of Failure to Meet the
Opacity Standard 19
References 21
iii
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FIGURES
Number Page
1 Comparison of measured and predicted ESP
performance 10
2 Predicted plume opacity versus scrubber pressure
drop for Harrington #1 16
3 Comparison of graded penetration curve predicted
by venturi model program with field data for
a variable throat venturi scrubber operating
at a venturi pressure drop of 48 cm w.c.
collecting fly ash 17
4 Predicted downwind opacity for 300 MW plant with
indicated emission rates and in-stack
opacities 22
TABLES
Number Page
1 Analysis of Coal Burned at Harrington #1 5
2 Design Specifications for Particulate Control
System at Harrington #1 6
3 Performance of Particulate Control System at
Harrington #1 7
4 Particle Size Data for Harrington #1 8
5 Input Data for ESP Modeling of Harrington #1 9
6 Comparison of Predicted and Measured Emissions
and Opacity for Harrington #1 13
7 Calculated Emissions and Opacity at Various
Scrubber Pressure Drops 15
8 Calculated Emissions and Opacity for ESP with
Venturi Scrubber 15
9 Estimated Range of Opacities for Existing ESP
and Various Scrubber Pressure Drops 20
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NOMENCLATURE
d - Geometric mass mean particle diameter, ym
f - Empirical factor in scrubber model
H - Effective height of emission, m
I - Intensity of light transmitted through aerosol
I - Intensity of light source
3-3-1
K - Light scattering parameter, cm m m
L - Optical path length, m
m - Particle refractive index
OQ - Downwind.plume opacity
0_ - In-stack plume opacity
3
Q - Gas flow rate, m /s
u - Wind speed, m/s
3
W - Mass concentration of particulate, g/m
5 - Plume transmittance dispersion parameter, m"
y 3
p - Particle density, g/cm
a - Geometric standard deviation
o - Verticle plume dispersion coefficient
-------
ACKNOWLEDGEMENTS
The assistance of Dr. Phil Lawless with the ESP modeling is gratefully
acknowledged. The cooperation of Southwestern Public Service Company
and the willingness of SWPS to provide data for this study are greatly
appreciated.
vi
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CONCLUSIONS
The results reported in this report show that the opacity measured
at Southwestern Public Service Company's Harrington Unit 1 is what one
should expect from an electrostatic precipitator (ESP)/marble bed scrubber
system. The results are consistent with the calculations of Sparks et
al. who showed that the particle size distribution created by ESP/
venturi scrubber systems is likely to be optically active.
The steps that can be taken to achieve 20% opacity at Unit 1 are:
1. Increase ESP specific collector area (SCA) by
25% and leave scrubber pressure drop the same.
2. Increase scrubber pressure drop by a factor
of 4 and leave the ESP alone.
3. Double the ESP SCA and remove the scrubber.
4. Replace the marble bed scrubber with a venturi
scrubber, increase pressure drop by 20%, and
leave the ESP alone.
None of these steps appear economically attractive. Future installations
that use ESP/scrubber systems should select venturi scrubbers to minimize
the energy consumption necessary to meet opacity standards. A plant with
particulate emissions that meet the mass standard but exceed the opacity
standard will emit more fine particulate matter and have a greater
impact on visibility downwind from the plant than will a plant with
particulate emissions that meet both standards.
RECOMMENDATIONS
More research on the plume opacity from ESP/scrubber systems is
needed. Although the results at Harrington Unit 1 are consistent with
model predictions, the possible effects of particle creation or growth
due to combined effects of S02» S03, and moisture cannot be ignored.
These effects will likely be important and, in fact, may be dominant in
situations where high sulfur coal is burned.
1
-------
Research on prediction of plume opacity from particulate control
devices should be encouraged.
INTRODUCTION
Particulate air pollution control regulations generally limit both
the mass of particulate that can be emitted and the opacity of the
plume. It is generally assumed that the two regulations are compatible;
i.e., if a plant meets the mass emission standard it will also meet the
plume opacity standard.
Recent theoretical results and laboratory scale experiments with a
particulate control system which consisted of an electrostatic precipitator
(ESP) followed by a scrubber indicate that the mass emissions required
to meet a given opacity limit may be very much lower than the mass
emission standard. Recent compliance tests of the ESP/scrubber system
at Southwestern Public Service Company's (SWPS) Harrington Unit 1 showed
a mass emission of about 19.4 ng/J (0.045 lb/10 Btu) and an opacity of
over 30%: this is in line with results of Sparks et al. The mass emission
is well under the current New Source Performance Standard (NSPS) of 43
ng/J (0.1 lb/10 Btu) but the opacity exceeds the standard of 20%.
SWPS has requested an adjustment of the opacity standard as it
applied to Unit 1. EPA's Division of Stationary Source Enforcement
(DSSE) has requested assistance from the Particulate Technology Branch
of EPA's Industrial Environmental Research Laboratory, Research Triangle
Park (IERL-RTP) to determine the reasonableness of the SWPS request.
This report is the result of that request.
A theoretical study of the particulate control system at Harrington
Unit 1 was undertaken to:
1. Estimate the opacity of emissions from the existing system.
2. Estimate the scrubber pressure drop required to meet
the 20% opacity standard with the existing ESP specific
collector area.
2
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3. Estimate the ESP specific collector area required
to meet the 20% opacity standard with the existing
scrubber pressure drop.
4. Estimate the ESP specific collector area required
to meet the 43 ng/J mass standard and 20% opacity
standard if the scrubber were eliminated.
Additional calculations not specifically related to SWPS were
performed to:
1. Estimate the impact on downwind plume opacity if
the in-stack opacity standard is not met.
2. Estimate the scrubber pressure drop required to
meet the 20% opacity standard if a venturi scrubber
were used instead of a marble bed scrubber.
Data necessary to carry out the theoretical calculations were
provided by Southwestern Public Service Company.
POSSIBLE REASONS FOR EXCESSIVE OPACITY
Several possible explanations of the high opacity at Harrington 1 have
been suggested. The most plausible are:
1. Creation of submicron particles due to inefficient
entrainment separation.
2. Creation of submicron particles due to reactions
of SO, or SO, with water in the plume.
L. *5
3. Creation of submicron particles due to water con-
densation.
Although the above three factors may influence the opacity at Unit
1, it seemed likely that the opacity/mass concentration relationship at
Harrington Unit 1 was similar to that reported by Sparks et al. in
their theoretical analysis of particle collection by ESP/scrubber systems.
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Therefore, extensive modeling of the ESP/scrubber system was undertaken
to predict the plume opacity of the current system and to estimate what
changes in the system would be necessary to achieve an opacity of less
than 20%.
DESCRIPTION OF THE SYSTEM
The steam generator for Harrington Unit 1 is a Combustion Engineering,
Inc. boiler, tangentially fired, capable of producing 1,219,265 kg of
steam/hour at 170 atm and 540°C while firing approximately 180,000
kg/hour of pulverized coal. The primary fuel for this unit is a low-
sulfur coal transported to Amarillo by rail from Gillette, Wyoming. A
proximate/ultimate analysis is given in Table 1.
The ESP/scrubber system at Unit 1 consists of a conventional ESP
followed by a marble bed scrubber. The design data for the system are
shown in Table 2. The full load compliance tests, Table 3, indicate
that the system is performing somewhat better than designed.
PARTICLE SIZE DATA
SWPS provided particle size distribution data for the ESP inlet and
ESP outlet, shown in Table 4. These data were used to estimate the
empirical factors in the ESP and scrubber models.
MODELS
ESP MODEL
2
The ESP computer model described by McDonald was used to model the
ESP. Input data for the model were provided by SWPS and are shown in
Table 5. The performance data provided by SWPS were used to estimate
sneakage, nonrapping reentrainment, and gas flow distribution factors in
the model. The agreement between the model predictions and the data is
good as shown in Figure 1. The empirical factors used in further modeling
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Table 1. ANALYSIS OF COAL BURNED AT HARRINGTON fT
Proximate Analysis - As Received
Moisture
Ash
Volatile
Fixed Carbon
Cal/g
Sulfur, %
S02, ng/J
Ultimate Analysis - As Received
Moisture
Carbon
Hydrogen
Nitrogen
Chlorine
Sulfur
Ash
Oxygen
Equilibrium Moisture
Cal/g at Equilibrium Moisture
Hardgrove Grindability Index
Typical ,2
28.26
4.74
32.00
35.00
100.00
4680
0.33
332
Typical t%
28.39
50.03
3.54
0.69
0.01
0.33
4.73
12.28
100.00
24.76
4910
53.27
Range, %
22.59 - 34.52
3.69 - 8.79
27.39 - 38.04
30.96 - 40.02
4314 - 5113
0.09 - 0.59
86 - 590
Range, %
23.40 - 34.52
45.26 - 53.70
2.84 - 4.13
0.41 - 1.02
0.00 - 0.16
0.09 - 0.59
3.69 - 6.64
10.25 - 15.00
19.23 - 27.33
4765 - 5427
37.00 - 67.80
*Data provided by Southwestern Public Service Company.
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Table 2. DESIGN SPECIFICATIONS FOR PARTICULATE CONTROL
AT HARRINGTON #1
Gas Flow Rate 2.571 x 106 Am3/h @/56°C
4 2
Electrostatic Precipitator Collector Area 4.067 x 10 m
Electrostatic Precipitator Design Efficiency 95%
Marble Bed Scrubber Pressure Drop (scrubber only) 17.8 cm H20
Marble Bed Scrubber Design Efficiency 50%
Total System Design Efficiency 97.5%
Liquid-to-Gas Flow Rate Ratio 4 x 10"3 m3/m3
Gas Velocity Through Marble Bed 1.98 m/s
Reheat Entrance Temperature 52°C
Reheat Exit Temperature 72°C
Stack Diameter 8.23 m
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Table 3. PERFORMANCE OF PARTICULATE CONTROL SYSTEM AT HARRINGTON #1
Flyash Concentration, ESP Inlet
Flyash Concentration, ESP Outlet
ESP Efficiency
Flyash Concentration, Scrubber Inlet
Flyash Concentration, Scrubber Outlet
Scrubber Efficiency
System Efficiency
Particulate Emission Rate
4.03 g/dNnT3
0.18 g/dNm3
95.5%
0.18 g/dNm3
0.069 g/dNm'
62.5%
98.3%
19.4 ng/J
dNm means dry normal cubic meter
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Table 4. PARTICLE SIZE DATA FOR HARRINGTON #1
Load 350 MWb
ESP Inlet
Run #1
ESP Outlet0
Cumulative fraction
Stage
1
2
3
4
5
6
7
1
2
3
4
5
6
7
dcn , ym
— -ou — — —
27.5
12
5.25
2.1
1.25
0.59
0.31
ESP Inlet
19
8.5
3.9
1.6
0.85
0.45
0.22
less than
0.796
0.388
0.215
0.109
0.0709
0.0651
0.0616
Run #2
0.453
0.334
0.223
0.105
0.0481
0.0275
0.0206
Stage dco,wn
ou
1 24
2 9.5
3 4.5
4 1.8
5 0.97
6 0.48
7 0.25
Cumulative fraction
less than
0.777
0.744
0.576
0.296
0.0916
0.0191
0.00880
All data furnished by Southwestern Public Service Company
bAll data for 350 MW
C0nly one run at ESP outlet
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Table 5. INPUT DATA FOR ESP MODELING OF HARRINGTON #1
Inlet Particle Size Distribution—as given in Table 3
Number of Electrical Sections—4
Plate Collector Area Per Section--!.018 x 104 m
4 2
Applied Voltage--2.345 x 10 volts; average current density—13.3 na/cm
4 2
Applied Voltage—2.446 x 10 volts; average current density--13.8 na/cm
4 2
Applied Voltage—3.080 x 10 volts; average current density--13.3 na/cm
Section .1:
Applied
Section 2:
Applied
Section 3:
Applied
Section 4:
4 2
Applied Voltage--2.814 x 10 volts; average current density—13.2 na/cm
Ion Mobility—2.826 x 10'V/V-s
Wire Radius—1.284 x 10~3m
Wire-to-Wire Spacing—0.228 m
Plate-to-Plate Spacing—0.228 m
Sneakage and Nonrapping Reentrainment Factor—0.1
Standard Deviation of Gas Velocity—0.50
-------
0.01
0.05
0.1
0.2
0.5
1
2
30
40
50
60
70
I I I I I I I I
LULU I
10 9 8 7 6 5 4 3 2 1 0.9 .0.7 0.6 0.5 0.4
PARTICLE DIAMETER, urn
Figure 1. Comparision of measured and predicted ESP performance
0.3
10
-------
are also given in Table 5.
SCRUBBER MODEL
Scrubber performance was modeled by modifying a venturi scrubber
model3'4 so that it fit the full load penetration data provided by SWP!
A value of 0.2 for the empirical factor f gave the required agreement.
The particle size distribution predicted by the scrubber model was
compared with data supplied by SWPS for 300 MW operation. A log-normal
fit was calculated for both the measured and predicted size distributions,
The results were:
d measured = 0.796 ym d predicted = 0.906 ym
y y
a measured =4.5 a_ predicted = 3.05
y y
With all the uncertainties in both the data and the calculations, the
agreement between the measured and predicted size distribution is good.
The predicted values of d and q fall within the 90% confidence interval
for the log-normal fit for the measured data.
All scrubber calculations were performed using a Texas Instruments
TI-59 calculator.
OPACITY MODEL
The opacity of the plume was estimated using a technique developed
by Ensor. Ensor has shown that
where I/I = transmittance through the plume (1 - opacity)
3
W = mass concentration of particles, g/m
L = optical path length, m
3
p = particle density, g/cm
-------
K = parameter describing effects of particle size
distribution,
wavelength of light, and refractive index of particles,
cm mm
The parameter K was calculated on a TI-59 using estimation procedures
reported by Deirmendjian. K calculated by this technique is in good
agreement with the results calculated by Ensor using complete solutions.
MODELING TECHNIQUE
The particle size distribution exiting the ESP was used as the
input particle size distribution for the scrubber model.
The predicted scrubber outlet size distribution was used to calculate
parameter K which was then used to calculate the plume opacity from
Equation 1. The refractive index and density of the particles were
adjusted until agreement between model and measured data was obtained.
o
The density selected was 2.4 g/cm (which is in good agreement with fly-
ash densities reported by others). The refractive index, m, selected
was 1.38 - 0.02i. Changes in refractive index did not greatly change
the calculated results. The model predictions for the existing system
are shown in Table 6.
As can be seen from Table 6, the plume opacity at Unit 1 is very
close to the measured value. Thus, it is fair to say, that the plume
opacity at Unit 1 is the opacity that would be expected from the particulate
control system.
The reason for the opacity at Harrington Unit 1 is the same as that
discussed by Sparks et al. Namely, the particle size distribution
created by an ESP scrubber system designed to give a given mass emission
is much more optically active than the particle size distribution from
an ESP alone.
12
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Table 6. COMPARISON OF PREDICTED AND MEASURED EMISSIONS AND OPACITY
FOR HARRINGTON #1
Measured Predicted3
Emission 19.4 ng/J 17.8 ng/0
Opacity 37% 35%
Scrubber Pressure Drop 18 cm hLO 18 cm H20
Scrubber Efficiency 0.62 0.65
M
Predictions based on f = 0.2, p = 2.4 g/cm , and m = 1.38 - 0.02i
13
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STEPS NECESSARY TO ACHIEVE 20% OPACITY
The situation at Unit 1 was examined to determine what steps could
be taken to comply with the 20% opacity limit. Three cases were examined.
1. Leaving the scrubber alone and modifying the ESP.
2. Removing the scrubber and modifying the ESP.
3. Leaving the ESP alone and increasing the pressure drop across
the scrubber.
The results of the calculations are:
Case 1 - The model predictions indicate that a 25% increase in
specific collector area would be required to meet the 20% opacity limit.
Case 2 - The ESP model predicts that the SCA of the existing ESP
would have to be doubled to comply with 40 ng/J and 20% opacity.
Case 3 - The results of Case 3 studies are shown in Table 7 and
Figure 2. Note that the pressure drop across the scrubber would have to
be increased by more than a factor of 4 to meet 20% opacity.
OPACITY IF A VENTURI SCRUBBER WERE USED
Harmon and Sparks have reported that venturi scrubbers are the
most energy efficient unaugmented type of scrubber. Thus it is of
interest, at least for new installations, to determine the pressure drop
necessary to give 20% opacity with a venturi scrubber instead of a
marble bed scrubber.
The venturi scrubber model with f = 0.5 accurately predicts the
performance of venturi scrubbers as is shown in Figure 3 taken from
Reference 7. The predicted particulate emissions rates and plume opacities
for a system identical to that at Harrington #1 (except that the marble
bed scrubber is replaced by a venturi scrubber) are shown in Table 8.
T4
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Table 7. CALCULATED EMISSIONS AND OPACITY AT VARIOUS SCRUBBER PRESSURE
DROPS FOR EXISTING MARBLE BED SCRUBBER9
Scrubber Pressure
Drop, cm H^O
19
32
48
64
167
Penetration
0.350
0.278
0.226
0.192
0.101
Efficiency
0.650
0.722
0.774
0.808
0.899
Emission
ng/J
17.8
14.2
11.5
9.8
5.1
Opacity
%
35
30
25
20
12
aAll calculations based on f = 0.2, Pn = 2.4 g/cm3, and m = 1.38 - 0.02i
Table 8. CALCULATED EMISSIONS AND OPACITY FOR ESP WITH VENTURI SCRUBBER3
Pressure Drop
cm H20
19
36
Scrubber
Penetration
0.0734
0.0355
Scrubber
Efficiency
0.927
0.965
Emission
ng/J
3.7
1.8
Opacity
%
13
7
aAll calculations based on f = 0.5, P = 2.4 g/cm3, and m = 1.38 - 0.02i
15
-------
0.50
a.48
5
<
LKL30
0.18
i i i r
PRESENT OPERATING POINT
I I I I I
10
20
30 40 50
PRESSURE DROP, cm H20
60
70
Figure 2. Predicted plume opacity versus marble bed scrubber pressure drop for Harrington
number 1.
-------
0.1
o
(0
0.01
ai
Z
UJ
Q.
0.001
0.0001
IN Nil I I I I Mill I I I I Mil
SR-52 MODEL
FULL SCALEVENTURI Q
I III UNI
i ill inn1
I I I Mill
0.1 1.0 10
AERODYNAMIC DIAMETER,
100
Figure 3.. Comparison of araded penetration curve predicted by
venturi model program with field 4ata for a variable throat
venturi scrubber operating at a venturi pressure drop
of 48 cm w.c. collecting fly ash.
17
-------
These calculations indicate that, even if opacity standards must be
met, an ESP/venturi scrubber system should be considered.
ACCURACY OF THE CALCULATIONS
The accuracy of the predicted plume opacity depends on two factors—
the accuracy of the mathematical models and the accuracy of the data
used in the models. These are two separate problems. Each is discussed
below.
The data used both to "calibrate" the models and as input to the
models were provided by SUPS. There is no absolute way to assess the
accuracy of these data. The data do seem reasonable. The inlet particle
size distribution is within the range one would expect for coal fired
boilers. The ESP outlet particle size distribution (the scrubber inlet
particle size distribution) is also reasonable.
The scrubber model used in the calculations may be a source of
error. Calvert's venturi scrubber model with a value of f = 0.2 was
used. Although the venturi scrubber model with f = 0.2 predicted the
overall penetration for full load of the existing system operated at a
pressure drop of 18 cm HpO, there are no data to show that the venturi
model with f = 0.2 would predict the performance of the marble bed
scrubber at higher pressure drops. However, it is unlikely that the
marble bed scrubber would be more efficient at higher pressure drops
than predicted by the model.
Probably the major source of uncertainty in the calculated results
lies in the opacity predictions. The opacity predictions are based on a
log-normal fit to the outlet particle size distributions. Unfortunately,
the outlet particle size distributions were never log-normal. A rough
estimate of the.uncertainty in the opacity predictions caused by the
assumption of log-normal size distribution can be obtained by calculating
opacity for log-normal size distributions with d and o values at the
y y
90% confidence level of the fitted log-normal size distribution.
18
-------
The range of estimated opacity shown in Table 9 is not a true
statistical 90% confidence limit for the predicted opacity. Rather it
is an indication of the overall uncertainty in the predicted opacity.
Methods of predicting opacity are under development which do not require
the log-normal assumption.
POSSIBLE ENVIRONMENTAL IMPACT OF FAILURE TO MEET THE OPACITY STANDARD
For a given mass emission, stack diameter, and particle refractive
index, the plume opacity from a source is a function of the particle
size distribution: the higher the opacity, the finer the particle size
distribution. Thus, a plant meeting the New Source Performance Standard
for mass but exceeding the NSPS for opacity will emit more fine particulate
matter than will a plant meeting both standards.
The opacity of the plume at the stack also affects the downwind
appearance of the plume (in the absence of secondary particulate formation)
Ens
by
Q
Ensor et al. have shown that the downwind opacity of a plume is given
v
0D - 1 - exp [.=__* _ ] (2)
° PpKu
where OD is downwind opacity as observed by an observer looking across
the plume
Q is the gas flow rate, m /s
£ is a parameter based on plume dispersion, m"
[ 1 + exp (- 2 H2/a2)]
u is the wind speed, m/s
3
W is the mass concentration of parti cul ate, g/m
3 -3 -1
K is the light scattering parameter, cm m m
H is the height of the emission, m
a is the vertical plume dispersion coefficient
19
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Table 9. ESTIMATED RANGE OF OPACITIES FOR EXISTING ESP AND VARIOUS
MARBLE BED SCRUBBER PRESSURE DROPS
Scrubber Predicted Range of Opacity for 9Q% Confidence
AP, on H20 Opacity, % Limits on Log-Normal Parameters, %
19 35 30-43
32 30 26 - 43
64 21 18-26
20
-------
Equation (1), which relates K to in-stack opacity, 0 , can be substituted
into equation (2) to give
0D - 1 - exp [ gy Q In Q-QS) ]
uL
Calculations, using equation (3) for a 300 MW power plant with a
particulate emission rate of 17 ng/J and an in-stack opacity of 40% and
emissions of 34 ng/J and an in-stack opacity of 20%, are shown in
Figure 4.
The plume for the Case 0 = 0.2 will probably not be visible when
the downwind distance exceeds say 0.5 km. However, the plume for the
Case Og = 0.4 w
exceeds 2-3 km.
REFERENCES
Case Og = 0.4 will probably be visible until the downwind distance
1. Sparks, L. E., Ramsey, 6. H., and Daniel, B. E., "Particle
Collection by a Venturi Scrubber Downstream from an Electrostatic Precipitator,"
EPA- 600/7- 78- 193 (NTIS PB 288203), October 1978.
2. McDonald, J. R., "A Mathematical Model of Electrostatic Precipitation
(Revision 1): Volume I. Modeling and Programming," EPA-600/7- 78-11 la (NTIS
PB 284614), June 1978.
3. Calvert, S, Goldshmid, J., Leith, D., and Meta, D., "Scrubber
Handbook— Volume I of Wet Scrubber System Study," EPA-R2-72-118a (NTIS PB
213016), August 1972.
4. Sparks, L. E., "SR-52 Programmable Calculator Programs for
Venturi Scrubbers and Electrostatic Precipitators," EPA-600/7- 78-026
(NTIS PB 277672), March 1978.
5. Ensor, D. S., "Smoke Plume Opacity Related to the Properties
of Air Pollutant Aerosols," Ph.D. Dissertation, University of Washington,
1972.
6. Deirmendjian, D., Electromagnetic Scattering on Spherical
Polydispersions. American Elsevier Publication, New York, N. Y. 1969.
21
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i mm
I i MUM i i 11 \m
METEOROLOGICAL CONDITIONS: STABLE—
WIND SPEED: 5mr1 —
EMISSION HEIGHT: 500m —
0.4 EMISSION RATE = 17 ng/J
0$ = 0.2 EMISSION RATE = 34 ng/J
I i ! HUH
i I I 1 1111
I i Mill
OJW1
0.2
0.4 0.6 0.8I1J) 2 4 6 8 10
DOWNWIND DISTANCE, km
20
40 60 80 100
Figure 4. Predicted downwind opacity for 300 MW plant with indicated emission rates
and in-stack opacities.
22
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7. Harmon, D. L. and Sparks, L. E., "Conclusions from EPA Scrubber
R&D," in Symposium on the Transfer and Utilization of Particulate Control
Technology: Volume 3.» pp 193-218, EPA-600/7-79-044b, February 1979.
8. Ensor, D. S., Sparks, L. E., and Pilat, M. J., "Light Trans-
mittance Across Smoke Plumes Downwind from Point Sources of Aerosol
Emissions," Atmos. Envir. 7, 1267, 1973.
23
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TECHNICAL REPORT DATA
(Please read InOructiom on the reverse before computing)
1. REPORT NO.
EPA-600/7-79-U8
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
En-stack Plume Opacity from Electrostatic
Precipitator/Scrubber System at Harrington Unit 1
5. REPORT DATE
May 1979
5. PERFORMING ORGANIZATION CODE
7. AUTHORIS)
Leslie E. Sparks
8. PERFORMING ORGANIZATION REPORT NO.
>. PERFORMING ORGANIZATION NAME AND ADDRESS
See block 12, below.
1O. PROGRAM ELEMENT NO.
EHE624A
11. CONTRACT/GRANT NO.
N.A.
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
Inhouse; 8-9/78
14. SPONSORING AGENCY CODE
EPA/600/13
is. SUPPLEMENTARY NOTES Author Sparks' phone is 919/541-2925.
. ABSTRACT Tne report g&QB results of theoretical modeling of particulate emission
and in-stack plume opacity for the electrostatic precipitator (ESP)/scrubber system
at Southwestern Public Service Company's Harrington Unit 1. The theoretical results
of an emission rate of 17.8 ng/J and opacity of 35% are in good agreement with data
from compliance testing of the unit. The calculations indicate that 20% opacity can be
achieved (1) by increasing specific collector area (SCA) of the ESP by 25% and leaving
the scrubber pressure drop alone, (2) by increasing scrubber pressure drop by a
factor of 4 and leaving the ESP alone, (3) by replacing the existing marble bed scrub-
ber with a venturi scrubber, increasing the pressure drop by 20%, and leaving the
SP alone, or (4) by doubling the SCA of the ESP and removing the scrubber. Cal-
culations showing the impact of high in-stack opacity on the downwind appearance of
the plume are also included.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.tDENTIFIERS/OPEN ENDED TERMS
COSATI Field/Group
Pollution Gas Scrubbing
Flue Gases Dust
Opacity Mathematical
Plumes Modeling
Electrostatic Precipitators
Scrubbers
Pollution Control
Stationary Sources
Particulate
13B
21B
14B
131
07A
13H
11G
12A
18. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (Thi* Report)
Unclassified
21. NO. Or PAGES
30
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (>-73)
24
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