EPA-600/2-75-018
August 1975
Environmental Protection Technology Series
STUDY OF FLUX FORCE/
CONDENSATION SCRUBBING
OF FINE PARTICLES
U.S. Environmental Protection Agency
Office of Research and Development
Washington, O.C. 20460
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STUDY OF FLUX FORCE/
CONDENSATION SCRUBBING
OF FINE PARTICLES
by
Seymour Calvert, Nikhil C. Jhaveri, and Timothy Huisking
A. P. T. , Inc.
4901 Morena Boulevard, Suite 402
San Diego, California 92117
Contract No. 68-02-1082
ROAP No. 21ADL-005
Program Element No. 1AB012
EPA Project Officer: Leslie E. Sparks
Industrial Environmental Research Laboratory
Office of Energy , Minerals , and Industry
Research Triangle Park, North Carolina 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, D. C. 20460
August 1975
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EPA REVIEW NOTICE
This report has been reviewed by the National Environmental Research
Center - Research Triangle Park, Office of Research and Development,
EPA, and approved for publication. Approval does not signify that the
contents necessarily reflect the views and policies of the Environmental
Protection Agency, nor does mention of trade names or commercial
products constitute endorsement or recommendation for use.
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environ-
mental Protection Agency, have been grouped into series. These broad
categories were established to facilitate further development and applica-
tion of environmental technology. Elimination of traditional grouping was
consciously planned to foster technology transfer and maximum interface
in related fields. These 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
9. MISCELLANEOUS
This report has been assigned to the ENVIRONMENTAL PROTECTION
TECHNOLOGY series. This series describes research performed to
develop and demonstrate instrumentation , equipment and methodology
to repair or prevent environmental degradation from point and non-
point sources of pollution. This work provides the new or improved
technology required for the control and treatment of pollution sources
to meet environmental quality standards.
This document is available to the public for sale through the National
Technical Information Service, Springfield, Virginia 22161.
Publication No. EPA-600/2-75-018
XI
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ACKNOWLEDGEMENTS
Air Pollution Technology, Inc., wishes to express
its appreciation to Dr. Leslie E. Sparks, E.P.A., Project
Officer, and Mr. James Abbott, E.P.A. for excellent tech-
nical coordination and for very helpful assistance in sup
port of our technical effort.
111
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TABLE OF CONTENTS n
r age
Acknowledgements _ • 1:L1
List of Figures .... • • V
List of Tables . xiii
Nomenclature ... xv
Abstract .... xvii
Foreword .. .xviii
Sections
Chapter 1 Introduction i
Chapter 2 Summary, Conclusions and Recommendations .... 3
Chapter 3 - Background 13
Chapter 4 - Experimental Pilot Plant 17
Chapter 5 Experimental Results and Discussions 49
Chapter 6 - FF/C Scrubber Performance Prediction Methods . . 71
Chapter 7 Economic Feasibility 93
Chapter 8 Future Research Recommendations 109
Appendices 1-5
References . 167
IV
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LIST OF FIGURES
No. Page
4-1 Pilot Scale Multiple Plate FF/C Scrubbing
System 18
4-2 Pressure Drop Characteristics of Plate 1. . .24
4-3 Pressure Drop Characteristics of Plate 2. . .25
4-4 Pressure Drop Characteristics of Plate 3. . . 26
4-5 Pressure Drop Characteristics of Plate 4. . . 27
4-6 Pressure Drop Characteristics of Plate 5. . .28
4-7 Process Flow Sheet for FF/C Spray Scrubbing
System 34
5-1 Penetration Versus Condensation Ratio, Four
and Five Plates SI
5-2 Penetration Versus Condensation Ratio, Four
Plates 52
5-3 Penetration Versus Condensation Ratio, Four
Plates 53
5-4 Penetration Versus Condensation Ratio, Five
Plates 54
5-5 Penetration Versus Condensation Ratio, Five
Plates, Distributed Steam Inlet 55
5-6 FF/C Scrubber Performance Comparison 56
5-7 Penetration Versus Condensation Ratio,
One Stage Spray 62
5-8 Penetration Versus Condensation Ratio,
One Stage Spray 63
5-9 Penetration Versus Condensation Ratio,
One Stage Spray 64
v
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No.
5-10 Penetration Versus Condensation Ratio,
One Stage Spray °b
5-11 Penetration Versus Condensation Ratio,
Three Stage Co-current Spray 66
5-12 Penetration Versus Condensation Ratio,
Three Stage Counter-current Spray 67
5-13 Comparison of Plate and Spray Scrubber
Results for lum Particles 68
5.A.I Particle Penetration Versus Aerodynamic
Diameter, Five Plates (Run #2 § #3) 133
5.A.2 Particle Penetration Versus Aerodynamic 133
Diameter, Five Plates (Run #4 $ #5)
5.A.3 Particle Penetration Versus Aerodynamic
Diameter, Five Plates (Run #6 § #7) 133
5.A.4 Particle Penetration Versus Aerodynamic 133
Diameter, Five Plates (Run #8 § #9)
5.A.5 Particle Penetration Versus Aerodynamic
Diameter, Four Plates (Run #10 § #11) . . . .154
5.A.6 Particle Penetration Versus Aerodynamic
Diameter, Four Plates (Run #12 § #16) . . . .134
5.A. 7 Particle Penetration Versus Aerodynamic ,.,,
Diameter, Four Plates (Run #13)
5. A. 8 Particle Penetration Versus Aerodynamic
Diameter, Four Plates (Run #14 § #15) .
5. A. 9 Particle Penetration Versus Aerodynamic
Diameter, Four Plates (Run #17 $ #18) .
5'A'10 ml™1?16 P!netratio* Versus Aerodynamic
Diameter, Four Plates (Run #19 $ #20) .
.135
VI
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No. Page
5.A.11 Particle Penetration Versus Aerodynamic
Diameter, Four Plates (Run #21 § #22) .... 135
5.A.12 Particle Penetration Versus Aerodynamic
Diameter, Four Plates (Run #25 § #27) .... 135
5.A.13 Particle Penetration Versus Aerodynamic
Diameter, Four Plates (Run #28 § #29) . . . . 136
5.A.14 Particle Penetration Versus Aerodynamic
Diameter, Four Plates (Run #32) 136
5.A.15 Particle Penetration Versus Aerodynamic
Diameter, Four Plates (Run #35 § #37) .... 136
5.A.16 Particle Penetration Versus Aerodynamic
Diameter, Four Plates (Run #36 $ #38) .... 136
5.A.17 Particle Penetration Versus Aerodynamic
Diameter, Four Plates (Run #41, #42 § #43). . ^37
5.A.18 Particle Penetration Versus Aerodynamic
Diameter, Four Plates (Run #48) 137
5.A.19 Particle Penetration Versus Aerodynamic
Diameter, Four Plates (Run #52 $ #53) .... 137
5.A.20 Particle Penetration Versus Aerodynamic
Diameter, Four Plates (Run #56 § #57) .... 137
5.A.21 Particle Penetration Versus Aerodynamic
Diameter, Four Plates (Run #60 $ #66) .... 138
5.A.22 Particle Penetration Versus Aerodynamic
Diameter, Four Plates (Run #61 § #68) .... 138
5.A.23 Particle Penetration Versus Aerodynamic
Diameter, Four Plates (Run #67 § #69) .... 138
5.A.24 Particle Penetration Versus Aerodynamic
Diameter, Four Plates (Run #73 § #74) .... 138
VII
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No.
5.A.25 Particle Penetration Versus Aerodynamic
Diameter, Four Plates (Run #70 § #75) • • • • L^
5.A.26 Particle Penetration Versus Aerodynamic
Diameter, Five Plates (Run #76, #77 § #78). . 139
5.A.27 Particle Penetration Versus Aerodynamic
Diameter, Five Plates (Run #79 $ #80) . . • • 139
5.A.28 Particle Penetration Versus Aerodynamic
Diameter, Five Plates (Run #81 § #82) . . . • 139
5.A.29 Particle Penetration Versus Aerodynamic
Diameter, Five Plates (Run #83, #84 8, #85). . 140
5.A.30 Particle Penetration Versus Aerodynamic
Diameter, Five Plates (Run #86 $ #87) .
140
5 A 31 Particle Penetration Versus Aerodynamic
Diameter, Five Plates (Run #88 § #89) . . . . 14U
5.A.32 Particle Penetration Versus Aerodynamic
Diameter, Five Plates (Run #90 $ #91) .
140
5. A. 33 Particle Penetration Versus Aerodynamic
Diameter, Five Plates, Steam Under #4
(Run #101) .................. 141
5. A. 34 Particle Penetration Versus Aerodynamic
Diameter, Five Plates, Steam Under #4
(Run #102) .................. 141
5. A. 35 Particle Penetration Versus Aerodynamic
Diameter, Five Plates, Steam Under #4
(Run #103) .................. 141
5. A. 36 Particle Penetration Versus Aerodynamic
Diameter, Five Plates, Steam Under #4
(Run #104) ...... ... . . 141
5. A. 37 Particle Penetration
Versus Aerodynamic
Undei #4
142
vni
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No. Pape
5.B.I Particle Penetration Versus Aerodynamic
Diameter, Single Stage Spray Scrubber
(Run #1 § #2) 153
5.B.2 Particle Penetration Versus Aerodynamic
Diameter, Single Stage Spray Scrubber
(Run #3 § #4) .- 15'5
5.B.3 Particle Penetration Versus Aerodynamic
Diameter, Single Stage Spray Scrubber
(Run #8 $ #10) ih-5
5.B.4 Particle Penetration Versus Aerodynamic
Diameter, Single Stage Spray Scrubber
(Run #13, #14 $ #16)
153
5.B.5 Particle Penetration Versus Aerodynamic
Diameter, Single Stage Spray Scrubber
(Run #17 § #19) 154
5.B.6 Particle Penetration Versus Aerodynamic
Diameter, Single Stage Spray Scrubber
(Run #21, #22 § #23) 154
5.B.7 Particle Penetration Versus Aerodynamic
Diameter, Single Stage Spray Scrubber
(Run #24, #25 § #28). 154
5.B.8 Particle Penetration Versus Aerodynamic
Diameter, Single Stage Spray Scrubber
(Run #29 § #30) 154
5.B.9 Particle Penetration Versus Aerodynamic
Diameter, Single Stage Spray Scrubber
(Run #32 § #34) 155
5.B.10 Particle Penetration Versus Aerodynamic
Diameter, Single Stage Spray Scrubber
(Run #35) 155
IX
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No.
5.B.11 Particle Penetration Versus Aerodynamic
Diameter, Single Stage Spray Scrubber 155
(Run #38)
5.B.I2 Particle Penetration Versus Aerodynamic
Diameter, Single Stage Spray Scrubber .
(Run #37 $ #39)
5.B.13 Particle Penetration Versus Aerodynamic
Diameter, One Stage (Run #42) ib
5.B.14 Particle Penetration Versus Aerodynamic
Diameter, One Stage (Run #43 $ #45) ihtl
5.B.15 Particle Penetration Versus Aerodynamic
Diameter, One Stage (Run #46 $ #50) lbb
5 B 16 Particle Penetration Versus Aerodynamic
Diameter, Single Stage (Run #48) 156
5 B 17 Particle Penetration Versus Aerodynamic
Diameter, One Stage (Run #51 § #54) 15 /
5.B.18 Particle Penetration Versus Aerodynamic
Diameter, One Stage (Run #55 § #56) is/
5 B 19 Particle Penetration Versus Aerodynamic
Diameter, One Stage (Run # 59 § #60) ib/
5.B.20 Particle Penetration Versus Aerodynamic
Diameter, One Stage (Run #61 § #63) 15 /
5.B.21 Particle Penetration Versus Aerodynamic
Diameter, One Stage (Run #64 $ #66) 158
5.B.22 Particle Penetration Versus Aerodynamic
Diameter, One Stage (Run #67 § #71) 158
5.B.23 Particle Penetration Versus Aerodynamic
Diameter, One Stage (Run #70 $ #72) 158
5.B.24 Particle Penetration Versus Aerodynamic
Diameter, 3 Stage Co-current Spray Scrub-
ber (Run #75, #77 § #79) 158
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No. Page
5.B.25 Particle Penetration Versus Aerodynamic
Diameter, 3 Stage Co-current Spray Scrub-
ber (Run #80 § #81) 159
5.B.26 Particle Penetration Versus Aerodynamic
Diameter, Three Stage Co-current Spray
Scrubber (Run #85, #86 § #88) 159
5.B.27 Particle Penetration Versus Aerodynamic
Diameter, Three Stage Co-current Spray
Scrubber (Run #89, #91 $ #92) 159
5.B.28 Particle Penetration Versus Aerodynamic
Diameter, Three Stage Co-current Spray
Scrubber (Run #95 § #96) 159
5.B.29 Particle Penetration Versus Aerodynamic
Diameter, Three Stage Counter-current
(Run #99 $ #101) 160
5.B.30 Particle Penetration Versus Aerodynamic
Diameter, Three Stage Counter-current
(Run #102 $ #103) 160
5.B.31 Particle Penetration Versus Aerodynamic
Diameter, Three Stage Counter-current
(Run #104 $ #105) 160
5.B.32 Particle Penetration Versus Aerodynamic
Diameter, Three Stage Counter-current
(Run #108 $ #109) 160
5.B.33 Particle Penetration Versus Aerodynamic
Diameter, Three Stage Counter-current
(Run #112 § #113) 161
5.B.34 Particle Penetration Versus Aerodynamic
Diameter, Three Stage Counter-current
(Run #121, #122 § #123) 161
5.B.35 Particle Penetration Versus Aerodynamic
Diameter, Three Stage Counter-current
(Run #114, #115 § #117) 161
xi
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No. f
6-1 Predicted Particle Collection Efficiency
for Sprays by Inertial Impaction and
Interception ...............
O A
6-2 Scrubber Area Covered by Sprays ......
6-3 Spray Scrubber Penetration Predictions
for 500 ym Drop Diameter ......... 86
6-4 Spray Scrubber Penetration Predictions
for 300 ym Drop Diameter
6-5 Experimental 1.0 ymA Particle Penetration
for Spray Scrubber
6-6 Experimental 1.0 ymA Particle Penetration
for Spray Scrubber 88
6-7 Experimental 1.0 ymA Particle Penetration
for Spray Scrubber 88
6.A Program for Correcting Particle Collection
on a Sieve Plate 164
7-1 Operating Cost Comparison of FF/C and
H. E. Scrubbers 96
7-2 Process Diagram for Cupola Gas Cleaning . . 104
Xll
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LIST OF TABLES
No. Page
2-1 Major Industrial Particulate Sources
For Which FF/C Scrubbing is Attractive. ... 4
4-1 Equipment Specifications 19
4-2 Stream Flow Rates of the Multiple Plate
FF/C Scrubbing System 20
4-3 Equipment Specifications 35
4-4 Stream Flow Rates of the Spray Scrubbing
System 37
4-5 Spray Scrubber Operation Modes 41
4-6 Multiple Plate Scrubber Operational Modes. . 47
5-1 FF/C Scrubber Performance Comparison .... 57
5.A.I Five Plate FF/C Scrubber; Operating
Conditions and Performance (Runs #1
through #9) 126
5.A.2 Four Plate FF/C Scrubber; Operating
Conditions and Performance (Runs #10
through #18) 126
5.A.3 Four Plate FF/C Scrubber; Operating
Conditions and Performance (Runs #19
through #45) 127
5.A.4 Four Plate FF/C Scrubber; Operating
Conditions and Performance (Runs #46
through #75) 128
5.A.5 Five Plate FF/C Scrubber; Operating
Conditions and Performance (Runs #76
through #91) 130
5.A.6 Five Plate FF/C Scrubber; Operating
Conditions and Performance (Runs #92
through #100) 131
Xlll
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No.
5.A.7 Five Plate FF/C Scrubber; Operating
Conditions and Performance (Runs #101
through #106)
5.B.I Horizontal Spray Scrubber; Operating
Conditions and Performance (Runs #1
through #23)
5.B.2 Horizontal Spray Scrubber; Operating
Conditions and Performance (Runs #24
through #40)
5.B.3 Horizontal Spray Scrubber; Operating
Conditions and Performance (Runs #41
through #50) ................ 147
5.B.4 Horizontal Spray Scrubber; Operating
Conditions and Performance (Runs #51
through #74) ................ 147
5.B.5 Horizontal Spray Scrubber; Operating
Conditions and Performance (Runs #75
through #96) ................ 149
5.B.6 Horizontal Spray Scrubber; Operating
Conditions and Performance (Runs #97
through #123) ................ 150
6-1 FF/C Spray Scrubber Design Equations .... 90
7-1 Gas Conditions and Fan Power Costs ..... 93
7-2 Cost Comparison of Cupola Emission
Control System ............... 108
8-1 Estimated Schedule of Performance ...... 119
8-2 Detailed Cost Breakdown ........... 122
XIV
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NOMENCLATURE
A = constant
B = constant
c = particle mass concentration, g/DNm3 gas
C' = Cunningham correction factor, dimensionless
d = diameter, cm, ym or ymA= ym (g/cm3) 1/z
d = mass mean diameter, ym or ymA
Jr &
E = efficiency, fraction or \
F = foam density, volume fraction liquid
G = gas rate, Kg/hr-m2 column area
hr = gas phase heat transfer coefficient, cal/sec-cm2 -°K
h, = liquid phase heat transfer coefficient, cal/sec-cm2 -°K
kp = gas phase mass transfer coefficient, gmole/cm2 -sec-atm
L = liquid rate, Kg/hr-m2 column area
n = particle number concentration, no. /cm3
Pt = penetration, fraction or %
Pt, = penetration for particle diameter "d ", fraction or I
Pt = overall penetration, fraction or \
AP = pressure drop, cm W.C. or atm
q = vapor condensed per particle, g
q = vapor condensed per unit mass of inlet particles,
mass fraction
q' = condensation ratio, g vapor condensed/g dry gas
R = particle concentration ratio defined in eq. (4-7),
dimensionless
u = velocity, cm/sec
r = radius, cm, ym, or ymA
v = cumulative volume concentration, cm3/cm3
V = gas volume swept per volume of spray, m3/!
a = geometric standard deviation, dimensionless
3
p = density, Kg/m3 or g/cm
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Subscripts
a = aerodynamic
d = drop
i = inlet
o = outlet
p = particle
t = total
xvi
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ABSTRACT
This report presents the results of a laboratory
pilot scale evaluation of two Flux Force/Condensation
(FF/C) scrubbers for the collection of fine particles.
FF/C scrubbing includes the effects of diffusiophoresis,
thermoporesis, Stefan flow and particle growth due to
the condensation of water vapor. Fine particles are those
smaller than 2 microns in diameter.
The two FF/C scrubbers tested were of multiple sieve
plate and horizontal spray configurations. Effects of
the scrubber configurations, liquid and gas flowrates,
particle number concentration and the amount of vapor
condensation were studied experimentally. Fractional
particle penetrations were measured with cascade impactors
and are presented in terms of particle penetration as a
function of particle size. The experimental results are
compared with predictions from mathematical models.
Optimum operational regions and the technical and
economic feasibility of FF/C scrubbing are determined and
demonstrated for a fine particle pollution source. It was
confirmed that FF/C scrubbing is an attractive control
method for fine particles when high efficiency is required
or when the gas is hot enough to evaporate the necessary
water vapor for condensation in the scrubber. A program
to demonstrate FF/C scrubbing at pilot scale for the con-
trol of fine particulate emissions from industrial sources
is described.
This report was submitted by Air Pollution Technology,
Inc., in fulfillment of Contract No. 68-02-1082, under the
sponsorship of the Environmental Protection Agency. Work
was completed on December 14, 1974.
xvi i
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FOREWORD
This report, "Study of Flux Force/Condensation Scrub-
bing of Fine Particles", is the final report submitted to
the Control Systems Laboratory for E.P.A. Contract No.
02-1082.
The principal objective of this program was to experi
mentally evaluate fine particle collection in two laboratory
pilot scale flux force/condensation (FF/C) scrubbers and to
determine the feasibility of application of FF/C scrubbing
to industrial sources. The main activities under the scope
of work were:
Based on the results of the previous theoretical and
experimental study of FF/C scrubbing;
1. Design and fabricate two pilot scale FF/C
scrubbers large enough for the exploration
of scale-up problems.
2. Conduct a laboratory pilot experimental
program to:
A. Determine feasibility for fine particle
collection
B. Develop design equations and scale-up
criteria
C. Determine optimum operating conditions
for FF/C scrubbing
D. Investigate potential operational and
maintenance problems
E. Determine effects of particle size dis-
tribution on the performance of FF/C
scrubbers
3. Prepare revised engineering and cost analysis
to incorporate results of the experimental study.
4. Recommend a detailed industrial pilot test program.
xvi ii
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CHAPTER 1
INTRODUCTION
A major drawback of present day scrubbers is the large
energy expenditure required to achieve high removal effi
ciencies for fine particles in the size range of 0.1 to 2
microns in diameter. This is due to the decreased effec-
tiveness of the inertial and diffusional collection mecha-
nisms for particles in this size range. Flux force and
water vapor condensation effects have the potential to im-
prove fine particle collection in low energy scrubbers.
In this report, flux forces are defined as those caused
by thermophoresis and diffusiophoresis (which includes the
diffusiophoretic and Stefan flow forces); but not electro-
phoresis. Accordingly, we consider only those FF/C scrub-
bers where particle removal from the gas is aided by tempera-
ture or vapor concentration gradients and particle growth is
due to vapor condensation. These effects can result from the
cooling of a hot, humid gas by contact with cold liquid, the
condensation of injected steam, or other means.
Several studies of scrubber operation where particle
collection was enhanced by vapor condensation have been
reported. Some investigations of the FF/C phenomena in par-
ticulate scrubbers have been made but the results have been
either of qualitative nature or provided limited quantitative
information applicable only to specific cases. Nothing ade-
quate for the design of optimum industrial scale FF/C scrub-
bing system was found in the literature.
A systematic developmental study of FF/C scrubbing
was started at Air Pollution Technology, Inc., under a pre-
vious contract, No. 68-02-0256, where the technical and
economic feasibilities of applying FF/C scrubbing for fine
particle collection were established. This study included
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theoretical development of design equations for FF/C sc
bers. A limited bench scale experimental study was also per
formed to examine critical areas of application of these
equations. The bench scale experimental study was extende
further under Contract No. 68-02-0285 to evaluate multiple
stage FF/C scrubbing, as reported in Calvert and Jhaveri
(1974). It was concluded that multiple stage or continuous
contact type scrubbers were most suitable for FF/C scrub-
bing application.
The purpose of the present study was to evaluate tech-
nical and economic feasibilities of FF/C scrubbing through an
experimental study of two laboratory pilot scale FF/C scrub-
bers. Based on the available information, multiple sieve
plate and horizontal spray FF/C scrubbers were selected. It
was also important to evaluate the effects of scrubber opera-
ting parameters so that the region of optimum FF/C scrubber
operation could be defined. To establish the economic feasi
bility, the operating costs were compared with high energy
scrubbers and a case study was made to compare the economics
of FF/C scrubbing system with high energy alternatives designed
to control gray iron cupola emissions.
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CHAPTER 2
SUMMARY, CONCLUSIONS AND RECOMMENDATIONS
SUMMARY
Flux force and water vapor condensation effects have
the potential to greatly improve the collection efficiencies
of low energy scrubbers for fine particles. The object of
the research reported here was to corroborate the limited
experimental and theoretical evidence of the feasibility
of FF/C scrubbing by conducting a detailed experimental
study of two laboratory pilot scale (14 to 28 m3/min or
500 to 1,000 CFM) FF/C scrubbers.
The economic feasibility of FF/C scrubbing was also
evaluated during this study. The results define the range
of emission properties for which FF/C scrubbing is deter-
mined to be economical. In general, FF/C scrubbing should
be considered when high removal efficiencies are desired
for fine particulate emissions; and the flue gas enthalpy
is higher than 100 Kcal/Kg or spent steam is available in
the plant. These conditions are common for industrial com-
bustion processes, which include several major stationary
pollution sources in the United States. The Midwest
Research Institute Report (1971) ranks sources based on the
total tonnage of particulates emitted annually.
Table 2-1 lists industrial sources of particulate pol-
lutants ranked among the top fifteen in the nation in the
M.R.I. Report (1971). Emission properties of these sources
are favorably suited for the application of FF/C scrubbing.
The annual emissions listed were determined by subtracting
the amount of emissions removed in the existing control
equipment from the total emissions. The "net control" listed
is the product of the average efficiency of control devices
and the application of the control devices for the industrial
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Table 2-1. MAJOR INDUSTRIAL PARTICULATE SOURCES
FOR WHICH FF/C SCRUBBING IS ATTRACTIVE
NOTE: The following information was taken from the Midwest Research Institute
Report (1971). The source number (Roman numeral) refers to its rank in
the U.S. as an industrial particulate pollution source.
NET
CONTROL EMISSIONS
SOURCE _™^_ FRACTION MKg/yr
ANNUAL
PRODUCTION
IV. IRON AND STEEL
A. Sinter Plants (Sintering
process)
B. Coke Manufacture
1. By-Product
2. Pushing § Quenching
C. Blast Furnace
D. Steel Furnaces
1. Open Hearth
2. Basic Oxygen
3. Electric Arc
E. Scarfing
VI. FOREST PRODUCTS
A. Wigwam Burners
B. Pulp Mills
1. Kraft Process
a. Recovery Furnace
b. Lime Kilns
c. Dissolving Tanks
2. Sulfite Process
(Recovery Furnace)
3. NSSC Process
a. Recovery Furnace
b. Fluid-Bed Reactor
4. Bark Boilers
46,300,000 MKg of Sinter
81,600,000 MKg of Coal
82,800,000 MKg of Coal
80,600,000 MKg of Iron
59,700,000 MKg of Steel
43,500,000 MKg of Steel
15,200,000 MKg of Steel
118,800,000 MKg of Steel
24,900,000 MKg of Waste
22,000,000 MKg of Pulp
2,300,000 MKg of Pulp
756,000 MKg of Pulp
3,200,000 MKg of Pulp
1,100,000 MKg of Pulp
470,000 MKg of Pulp
0.90
0
.99
.40
.99
.78
.68
91
94
,30
.91
.91
.70
46,300
81,600
19,000
52,600
306,000
9,000
16,300
57,200
120,000
149,000
29,900
38,100
9 ,000
900
38 ,100
74,400
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TABLE 2-1 (Continued)
SOURCE
VII. LIME
A. Rotary Kilns
B. Vertical Kilns
VIII. PRIMARY NONFERROUS METALS
A. Aluminum
1. Calcining of Hydroxide
2. Reduction Cells
a. H. S. Soderberg
b. V. S. Soderberg
c. Prebake
B. Copper
1. Roasting
2. Reverb. Furnace
3. Converters
C. Zinc
1. Roasting
a. Fluid-Bed
b. Ropp, multi-hearth
2. Sintering
3. Distillation
D. Lead
1. Sintering
2. Blast Furnace
3. Dross Reverb. Furnace
XI. ASPHALT
A. Paving Material
1. Dryers
2. Secondary Sources
ANNUAL
PRODUCTION
14,700,000 MKg of Lime
1,600,000 MKg of Lime
5,300,000 MKg of Aluminum
730,000 MKg of Aluminum
640,000 MKg of Aluminum
1,600,000 MKg of Aluminum
520,000 MKg of Copper
1,300,000 MKg of Copper
1,300,000 MKg of Copper
690,000 MKg of Zinc
138,000 MKg of Zinc
560,000 MKg of Zinc
560,000 MKg of Zinc
420,000 MKg of Lead
420,000 MKg of Lead
420,000 MKg of Lead
228,000,000 MKg of Material
NET
CONTROL
FRACTION
0.81
.39
90
40
64
64
85
81
81
98
85
95
86
83
50
.96
.96
EMISSIONS
MKg/yr
267,000
3,600
52,600
31,700
9,000
18,100
6,000
25,400
29,900
13,600
3,600
2,700
13,600
15,400
9,000
1,800
150,000
36,300
-------
SOURCE
B. Roofing Material
1. Blowing
2. Saturator
XII. FERROALLOYS
A. Blast Furnace
B. Electric Furnace
XIII. IRON FOUNDRY
A. Furnaces
XIV. SECONDARY NONFERROUS METALS
A. Copper
1. Material Preparation
a. Wire Burning
b. Sweating Furnaces
c. Blast Furnaces
2. Smelting § Refining
B. Aluminum
1. Sweating Furnaces
2. Refining Furnaces
3. Chlorine Fluxing
C. Lead
1. Pot Furnaces
2. Blast Furnaces
3. Reverb. Furnaces
D. Zinc
1. Sweating Furnaces
a. Metallic Scrap
b. Residual Scrap
2. Distillation Furnace
TABLE 2-1 (Continued)
ANNUAL
PRODUCTION
5,680,000 MKg of Asphalt
NET
CONTROL
FRACTION
0.50
540,000 MKg of Ferroalloy .99
1,900,000 MKg of Ferroalloy .40
16,000,000 MKg of Hot Metal .27
270,000 MKg Insulated Wire 0
58,000 MKg of Scrap .19
260,000 MKg of Scrap .68
1,100,000 MKg of Scrap .57
450,000 MKg of Scrap
920,000 MKg of Scrap
120,000 MKg of Cl Used
48,000 MKg of Scrap
108,000 MKg of Scrap
500,000 MKg of Scrap
47,000 MKg of Scrap
190,000 MKg of Scrap
210,000 MKg Zn Recovered
.19
.57
.25
.90
.90
.90
.19
.19
.57
EMISSIONS
MKg/yr
2,700
12,700
900
140,000
95,300
37,200
1,800
15,400
5,400
900
46,300
900
2,700
2,700
1,800
-------
category. The information and ranks were taken from the
M.R.I. Report (1971). It is clear from Table 2-1 that
FF/C scrubbing is a feasible and attractive particulate
control method for several manor industrial sources.
Experimental Program
Based on results from our previous studies, multiple
plate and spray FF/C scrubbing configurations were selected
for the experimental study. Test aerosols with fine iron
oxide and titanium dioxide particles were generated in the
laboratory by dry dispersing the respective pigment powders.
Gas heating and steam were used to precondition the scrubber
gas to the desired experimental conditions. A forced draft
cooling tower was used to cool the recirculating scrubber
water.
Effects of several operating parameters were studied
during the experiment. In general, particle collection in
the FF/C scrubbers was higher as the amount of vapor con-
densed per unit of gas scrubbed (condensation ratio) was
increased or the inlet particle number concentration was
decreased. Addition of a fifth plate to the multiple plate
FF/C scrubber, considerably improved the performance for
the same condensation ratio. But changing the liquid to
gas flowrate ratio within the scrubber operative range
showed no significant effect on scrubber performance. A
more uniform distribution of vapor condensation over the
stages or plates of the multiple plate scrubber was also
found to result in better scrubber performance.
A mathematical model was used to predict the experi
mentally determined multiple plate FF/C scrubber perfor-
mance. The model was based on the theoretical collection
of particles in the bubbles on a sieve plate due to the
FF/C phenomena. Inability to predict the plate hydro-
dynamics and the gas liquid contact area remains the
critical area of uncertainty in the application of the
model. However, the model can predict scrubber perfor-
7
-------
mances that correlate well with experimental results.
The model can now be used to scale-up the FF/C scrubber
and design industrial FF/C scrubbing systems.
Spray Scrubber
Operating parameters besides the condensation ratio
and inlet particle number concentrations which were studied
for the spray FF/C scrubber are: the effect of the spray
drop size, the effect of decreasing cooling water require-
ment, the mode of overall gas-liquid contact and the scrub-
ber inlet liquid flowrate. The scrubber performance was
better when the size of sprayed drops was smaller and when
the amount of cold water sprayed in was higher for the
same condensation ratio. The performance was also better
when the scrubber inlet gas was exposed to the colder water
spray first, resulting in the maximum temperature and vapor
pressure gradients.
A mathematical model for the FF/C spray scrubber based
on the unit mechanism approach gave only partial agreement
with the experiment. Performance for cold gas without
FF/C phenomena benefits was compared with a mathematical
model based on accounting for collection by single drops as
they decelerate after leaving the spray nozzle. The correla-
tion was good for particles of about 1.0 ymA diameter. How-
ever, experimental efficiencies were higher for smaller
particles, possibly because of particle collection on the
back of drops. Experimental efficiencies were lower for the
collection of larger particles, possibly indicating lower
utilization of sprayed liquid, higher drop coalescence and
gas channeling. Design equations were developed empirically
to represent the experimental results, and be used for
scale-up and design of industrial FF/C scrubbing systems
with similar spray configuration.
-------
Costs
Operating costs of a FF/C scrubber were compared to
those of a high energy scrubber capable of equal performance
The costs of electrical power at $0.03 KWH, purchased steam
at $6.40/MKg and recirculating cooling water at $0.9/MKg
were used for this comparison. The results indicate that
when high fine particle collection efficiencies are required
or when the gas to be scrubbed is hot or humid, FF/C scrub-
bing is economically more attractive.
In an earlier report, Calvert et al. (1973) had evalu-
ated the economic feasibility of FF/C scrubbing compared
to other alternatives for two industrial sources. Based
on the additional information on the performance of FF/C
scrubbing obtained from this research, the economics of an
FF/C system for a gray iron cupola were estimated. Good
cost and performance data for a high energy (H.E.) scrubber
on a cupola were available from another study and provided
a basis for comparison. Capital investment requirements
for the two systems are roughly the same but the H.E. scrub-
ber costs about 70% more than the FF/C system for all annual
operation expenses except labor, maintenance, liquid treat-
ment, and solid waste disposal. Most of the cost advantage
of FF/C scrubbing is due to a $63,500/yr higher power cost
for H.E. scrubbing.
-------
CONCLUSIONS
The following conclusions can be drawn from the results
of this study:
1. The experimental study confirmed previous pre-
dictions of the technical feasibility of FF/C
scrubbing. High collection efficiencies (>95%)
for fine particles can be achieved with a conden-
sation ratio of about 0.15 g vapor condensed/g
dry gas, in a FF/C scrubber.
2. Performances of the multiple plate and hori
zontal spray FF/C scrubbers were roughly compar-
able for the higher condensation ratio range and
for the same particle concentration. Thus, the
horizontal spray FF/C scrubber is economically
more attractive due to the lower capital cost and
the lesser power requirement for scrubbing the
same amount of gas. However, reasonably fine
spray with the drop diameter of about 400 ym is
needed to achieve the high efficiency. Thus, if
a slurry is used to scrub the gas, and if the
scrubber operation is not continuous, plugging of
the spray nozzles may become a serious operational
problem. The plate scrubber is more adaptable to
changes in the flue gas conditions although the
spray is superior for gas "turn down" (i.e.,
lower gas rate).
3. Of the several mechanisms involved in FF/C scrub-
bers, diffusiophoresis and inertial impaction
enhancement by particle growth, which are prac-
tically independent of particle size, are the most
important for fine particle collection. Thus,
the condensation ratio and inlet particle number
are significant operating parameters for FF/C
scrubbing.
10
-------
4. Effects of other operating parameters, such as
the gas and liquid flowrates and contact scheme,
on the performance of the two FF/C scrubbers have
been experimentally studied. The results can be
used to design the optimum FF/C scrubbing system
depending on the specific properties of the in-
dustrial pollution sources.
5. Based on the experimental data, mathematical
models and empirical design equations are de-
scribed, which can be used to scale-up similar
FF/C scrubbers for industrial applications.
6. Economic considerations define the most favorable
area of application for FF/C scrubbing as those
situations in which the enthalpy of vaporization
is available from the gas to be cleaned, or when
high collection efficiencies are required for
fine particles, or when future capacity expansion
is anticipated, or a combination of the three.
The smaller the size of the particles to be
scrubbed, the more economically attractive
FF/C scrubbing will look. These conclusions are
illustrated by a case study of an economic com-
parison of FF/C and high energy scrubbing systems
for a gray iron cupola.
RECOMMENDATIONS
The laboratory pilot scale experimental study reported
here has established the technical and economic feasibility
of FF/C scrubbing. Engineering design equations for the two
configurations studied are also described. The following
research and developmental program is recommended:
1. Experimentally demonstrate the feasibility of
FF/C scrubbing on selected industrial sources.
11
-------
Pilot scale systems with capacities to scrub from
2.4 to 4.8 m3/sec (5,000 to 10,000 CFM) should be
used for demonstration. Problem industrial sources
with fine particulate emissions and hot or humid
flue gas should be selected for the demonstration.
The FF/C scrubbing systems should be designed to
operate at the optimum conditions with flexibility
to account for process changes. These demonstra-
tion programs, for three industrial sources: a
glass furnace, a secondary non-ferrous metal re-
covery furnace, and a foundry cupola, are detailed
in the report.
Theoretical and experimental evaluation of other
scrubbing configurations, such as a mobile bed
(TCA) scrubber should be made to determine the
best configuration applicable to FF/C scrubbing
systems.
Evaporative cooling of scrubber liquid containing
suspended and dissolved solids is critical for
the economic feasibility of FF/C scrubbing. The
cooling towers generally available use packings
which are susceptible to scaling by the solids.
A different configuration, such as using sprays
instead of the packings, may be more applicable.
Experimental development of the cooling towers on
a laboratory and subsequently on an industrial
pilot scale is clearly warranted.
Theoretical and experimental study of the speci
fie details of plate hydrodynamics, spray utili
zation, heat and mass transfer in gas-liquid
systems, the nucleation of condensation and other
matters which significantly influence FF/C mecha-
nisms should be made in order to resolve the
present areas of uncertainty.
12
-------
CHAPTER 3
BACKGROUND
Flux force effects on particles have been known for
many years and the background is reviewed and discussed
in depth by authors such as Waldmann and Schmitt (1966),
Goldsmith and May (1966), Hidy and Brock (1970) and Calvert
et al. (1972). The studies reported by these authors in-
clude both theoretical and experimental work. The experi-
mental systems were designed so as to be readily definable
and were much simpler than a scrubber in terms of the num-
ber of phenomena and the unsteady conditions involved.
Several studies of scrubber operation have also been
reported where particle collection was enhanced by vapor
condensation, such as Schauer (1951) and Lapple and Kamack
(1955). However, systematic studies of the effects of
FF/C phenomena were attempted only recently. Rozen and
Kostin (1967) studied the collection of fine oil mist in
a perforated plate column under controlled conditions of
vapor condensation. They found that their results could
be represented by an empirical equation relating the par-
ticle penetration, "Pt", with the mass of steam condensed
per gram of inlet particles, "q " as:
Pt = 12.5 qm0'56 (3-1)
A study of steam injection into a laboratory scale scrubber
was carried out by Lancaster and Strauss (1971) . They
measured an increase in particle collection efficiency
which was in direct proportion to the amount of steam in-
jected rather than the amount of vapor condensed. They
concluded that the increase in collection efficiency was
due to particle growth.
13
-------
Calvert et al. (1973) present a detailed description
of the previously reported studies on FF/C scrubbing.
Technical feasibility of FF/C scrubbing was established
in this report, based on theoretical development of FF/C
scrubber performance models and limited bench scale ex-
perimental work. Further bench scale experimental work,
reported by Calvert and Jhaveri (1974) led to the follow-
ing conclusions:
1. Diffusiophoresis and inertial impaction enhanced
by particle growth are the most significant par-
ticle collection mechanisms in FF/C scrubbers,
while thermophoresis has a minor effect. All of
these mechanisms are practically independent of
the particle size.
2. Performance of an FF/C scrubber depends heavily
on the amount of vapor available for condensa-
tion and the number concentration of particles.
3. Multiple stage or continuous contact type of
scrubbers are most suitable for FF/C application.
They can be readily adapted to provide different
conditions and geometry along the gas path to
accommodate changing flowrates and particle con-
centrations .
4. The most critical assumptions for the application
of FF/C scrubber engineering design equations are
the specific details of heat and mass transfer
mode of gas-liquid contact and nucleation of con-
densation on the particles. Better particle col
lection is obtained if the ratio of gas phase mass
transfer coefficient to the liquid phase heat
transfer coefficient is higher.
14
-------
Based on the above information, multiple plate and
spray scrubber configurations were selected for experi-
mental study. The multiple plate FF/C scrubber configuration
has the benefit of higher transfer coefficient ratio compared
to the packed bed configuration. Also, due to the distinct
separation of stages, it permits higher operational flexibil
ity and allows for accurate measurement of stream conditions
within the scrubber. The spray FF/C scrubber has the benefit
of low energy requirement and low capital costs since high
gas velocity is permissible, compared to the other low energy
scrubbers considered.
The following parameters were determined to affect
the particle collection mechanisms, diffusiophoresis and
inertial impaction enhanced by particle growth, most sig-
nificantly:
1. Multiple plate scrubber
a. Condensation ratio
b. Particle number concentration
c. Number of stages or plates
d. Ratio of the scrubber Irquid to gas flowrates
e. Distribution of vapor condensation over the
stages or plates
2. Spray scrubber
a. Condensation ratio
b. Particle number concentration
c. Spray drop diameter
d. Cold liquid flowrate
e. Overall gas-liquid contact mode
f. L/G
Effects of these parameters on scrubber performances
were experimentally evaluated in this study.
15
-------
CHAPTER 4
EXPERIMENTAL PILOT PLANT
Based on the theoretical considerations described in
the previous section, a multiple sieve plate scrubber and
a horizontal spray scrubber were selected for the study of
FF/C scrubbing on a pilot plant scale. During this study,
fractional penetrations of fine particles through the scrub
bers were experimentally determined for several scrubber
operating conditions. In this section, the following in-
formation is described for both the FF/C scrubber systems:
1. Details of the pilot scale scrubber systems
2. Scrubber operating procedures
3. Particulate sampling procedures
4. Methods of data analyses and calculation
5. Accuracy of measurements
6. Operational conditions studied
THE MULTIPLE SIEVE PLATE FF/C SCRUBBER
Pilot Scale Scrubber System
The schematic process flow diagram of the pilot scale
FF/C scrubber system is shown in Figure 4-1. Components of
the scrubber system are listed in Table 4-1. The scrubber
had a design capacity of 0.24 actual m3/sec (500 ACFM) in-
let gas flowrate. Since it was decided to test the hori
zontal spray scrubber, the second FF/C scrubber studied,
at a gas flowrate of 0.47 actual m3/sec (1,000 ACFM), the
remaining components of the scrubber system were designed
to handle this higher capacity. As an illustration, flow-
rates in the lines shown in Figure 4-1 are described in
Table 4-2, when the inlet gas stream to the scrubber is at
77°C, saturated with water vapor. The FF/C scrubber and
the particle generators are described below together with
the instrumentation and calibration procedures.
17
-------
air, scrubber gas
water, slurry
steam
natural gas
m
14
11
m
13
15
1
1C
1
c
1
1
1
1
1
LL
->-
3
4
1
d
2
•
•
6
k
f
h —
—
(--»-
L_^_
— »—
C\\\\\\\\
f / / / ////
^
. L
,r_U
L ll
Jr_L.
4
r~!
i
i
—1
H— H
18 | |19
20
m
17
16
h i
Figure 4-1 - The pilot scale multiple plate FF/C scrubbing system,
-------
Table 4-1. EQUIPMENT SPECIFICATIONS
Equipment:
a. Prefilter
Four automobile air filters with a capacity
of 8.5 m'/min air, each
b. Heat exhanger
Gas-fired air heater to heat air from 24°C to
100°C
c. "Absolute" filter
MSA "Ultra-air" filter with a capacity of 0.476
m^/sec of gas
d. Particle and steam mixer
Disc and donut type mixer 0.25 sec residence
time.
e. Particle generator
Up to 101 particles/cm^ of scrubber gas inlet
f. FF/C scrubber
Sieve plate scrubber
g. Scrubber exhaust fan
Centrifugal fan with design capacity of
0.476 m3/sec and AP of 50 cm W.C.
h. Pumps
227 £/min and 15 m head (60 gpm and 50 ft of head)
i. Pump
227 Jl/min and 15 m head, self priming
j . Water cooling tower
A splash type cooling tower. Cooling range
47°C at 190 £/min
k. Boiling water treatment
11.3 Jl/min ion exchanger
£. Steam boiler
760 Kg/hr steam at 2.0 atm
m. Cooling tower fan
4.25 m3/sec and 2.5 cm W.C.
19
-------
Table 4-2. STREAM FLOW RATES OF THE MULTIPLE PLATE FF/C SCRUBBING SYSTEM
'Stream
No.
L
1 § 2
3 § 4
6
7
8
9
10
11
12
_
Compositions
0.0675 mole
H20/mole, air mix.
it
0.696 mole
H20/mole, air mix.
0.475 mole
H20/mole, air mix.
0.00675 mole
H20/mole, air mix.
Natural Gas
0.154 mole
H20 mole, air mix.
Steam
Steam
Temp
°C
29°
100°
77°
32°
29°
29°
232°
106°
106°
Vol. Flow
m3/sec
0.129
0.153
0.240
0.132
0.056
0.0045
0.104
-
-
£/sec
-
-
-
-
-
_
-
-
-
Mass Flow
Kg/hr.
514
514
735
530
221.4
35.6
257
221
221
Enthalpy*
Kcal/Kg
9.65
42.5
290
26.8
9.65
_
190
644
644
Press .
AP =0.5 cm
fli!2
W.G.
15.7 cm W.G.
20.8 cm W.G.
46.2 cm W.G.
-
20 cm W.G.
-
1 .33 Kg/cm2
1.33 Kg/cm2
air or water
-------
Table 4-2. STREAM FLOW RATES OF THE MULTIPLE PLATE FF/C SCRUBBING
SYSTEM (Continued)
Stream
No.
13
14
15
16
17
18
19
Compositions
Steam
City Water
Natural Gas
City Water
0 .00675 mole
H-0/mole, air mix.
Process Water
Process Water
Temp.
°C
106°
24°
29°
24°
29°
32°
1
74°
Vol. Flow
m3/sec
-
-
-
-
4.75
-
-
a/sec
-
0.071
-
-
-
0.97
1.03
Mass Flow
Kg/hr.
221
254.5
0.0006
13.8
19,800
3,500
3,600
Enthalpy*
Kcal/ Kg
644
24
-
24
9.65
32 .2
70.5
Press .
1.33 Kg/cm2
3.16 Kg/cm2
20 cm W.G.
3.16 Kg/cm2
-
-
-
air or water
-------
FF/C Scrubber
Scrubber shell: 0.3m x 0.3m x 5.2m, fabricated from 14 ga
cold rolled steel. It had a removable flange in the
front, for access into the scrubber. The inside walls
were coated with a high temperature polyester finishing
resin for protection against corrosion and leaks.
Plate design: The scrubber could be operated with a maximum
of five plates. All the plates were identical, 1.5 mm
thick, with 3.2 mm round perforations, adding up to a
free area of 9% per plate. The perforations were
countersunk to avoid the formation of a vena contracta
in the gas jet through a perforation. The plate active
area was 9.3 x 10'2 m2. Each plate had straight 5.1 cm
x 30.5 cm inlet and outlet wiers, with three 2.5 cm
downcomer pipes installed behind the outlet wier.
Liquid flow: The scrubber inlet liquid from the cooling
tower holding tank was introduced on the top plate of
the scrubber. It then cascaded down through the
plate downcomers to a 0.3m x 0.4m x l.lm enclosure
provided at the bottom of the scrubber, from which it was
drained into the 200 liter scrubber water holding tank.
Entrainment separator: A wire mesh entrainment separator was
installed in the scrubber over the top plate. The
0.3m x 0.3m x 0.15m entrainment separator with 98.2%
voidage was made from 0.28 mm stainless steel wire in
a standard knit design.
Steam introduction: Steam introduction manifolds were in-
stalled under all the five plates. Up to 120 Kg/hr of
dry saturated steam could be introduced through 20
round holes, 1 cm in diameter, from each manifold
The steam could thus be introduced as turbulent let
through the holes, which were located to promote steam
mixing in the gas stream below the plates.
22
-------
Plate pressure drop characteristics were studied
for each of the five plates in the scrubber. These
characteristics define the operating gas and liquid flow-
rates on the sieve plate and are also essential for scale-
up of the sieve plate column. The operating regions of a
sieve plate are well discussed by McAllister, et al. (1958).
The pressure drop characteristics are plotted as a
function of gas and liquid mass flowrates on Figures 4-2
through 4-6 for the five plates. The dry plate pressure
drops are also shown for reference. The plates are num-
bered successively from the bottom to the top plate. The
pressure drop characteristics were similar to the charac-
teristics for type III sieve plates, as discussed by
McAllister, et al. (1958). These characteristics were
obtained using ambient air and water. The "weep" points
are indicated on each plot by arrows. During the scrubber
performance study, the plates were operated at gas and
liquid flowrates above the "weep" points and below the
flooding conditions.
Particle Generators
Two aerosols were used during the study, generated by
dry dispersing pigment powders. In each case, the powder,
after drying, was sieved through a 16 mesh screen. The
pure black iron oxide powder, purchased from Pfizer Incor-
porated, was then fed to the inlet of a high pressure
blower through a screw feeder arrangement. The radial
blades of the blower were drilled to increase recircula-
tion and shear on the dispersed particles within the blower
casing.
The second pigment used was "Unitane OR-600" titanium
dioxide powder, purchased from the American Cyanamid Company,
23
-------
U
eu
§
w
Pi
£>
LO
CO
w
ec;
PH
W
H
10.0
5.0
3.0
2.0
I ' r
2= 29,300
= 14,700
— O = 2,450
— WEEP POINT
X
I ' I ' I TTT
1.5
3.0
5.0
10.0
GAS MASS FLOW RATE X 10 ~3, Kg/hr-m2 COLUMN AREA
Figure 4-2 Pressure drop characteristics
of the bottom plate (plate 1) .
L is in
24
-------
10.0
u
e
u
o
f*
o
Pi
;=)
CO
CO
w
H
5.0
3.0
2.0
1.0
O *
A =
O =
—iiii , i , ir
29,300 WEEP
14,700 POINT
2,450
\
1.5
3.0
5.0
10.0
GAS MASS FLOW RATE X 10 3, Kg/hr-m2 COLUMN AREA
Figure 4-3 - Pressure drop characteristics of
Plate 2. L is in Kg/hr-m2.
-25
-------
10.0
5.0
e
u
eu
P 3.0
w 2.0
1.0
I ' I ' I
WEEP
POINT
1.5
3.0
5.0
10 .0
GAS FLOWRATE x 10 "3, Kg/hr-m2 COLUMN AREA
Figure 4-4 Pressure drop character-
istics of Plate 3. L is in
26
-------
10.0
s 5.0
o
§
Q
W
Pi
£3
in
CO
W
H
3.0
2.0
1.0
- O =
^ I
29,300
14,700
2,450
I ' I ' I
WEEP
POINT
I IT
I
I . I ,1111
1.5 3.0 5.0 10.0
GAS FLOWRATE x 10-3, Kg/hr-m2 COLUMN AREA
Figure 4-5 - Pressure drop character-
istics of Plate 4. L is
in Kg/hr-m2.
27
-------
10.0
5.0
6
o
P-,
§ 3.0
Q
Pi
w
CO
PH
w
H
2.0
1.0
I ' I
2= 29,300
= 14,700
O= 2,450
I ' I ' I
WEEP
POINT
1.5
3.0
5.0
10.0
GAS FLOWRATE x 10"3, Kg/hr-m2 COLUMN AREA
Figure 4-6 Pressure drop characteristics
of Plate 5. L is in Kg/hr-m"
28
-------
The powder was fed by a screw feeder arrangement into a
compressed air ejector, immediately downstream of a
0.64 cm orifice. The compressed air pressure upstream
of the orifice was maintained at 0.7 atm, gage.
The feed rates of the powders were controlled
depending on the particle loading required. A cyclone
and a multiple round jet impactor, both with cut diameters
of 4 ymA, were used in series to remove coarse particles
from the dispersed aerosols. Electrostatic charges on
the dispersed particulates were then neutralized with
nine "Staticmaster" ionizing units supplied by Nuclear
Products Company, with 500 microcuries of Polonium 210
in each. These units were located in the aerosol duct
upstream of the mixing section.
Instrumentation and Calibration
The inlet gas flowrate was measured with a venturi
meter located in the 15.2 cm gas ducting. It was cali
brated against flowrates measured by standard pitot tube
traverses, in the range of 0.05 to 0.18 normal m3/sec.
Scrubber system liquor flowrates were also measured by
venturimeters and rotameters installed in the 3.8 cm
piping. They were calibrated by measuring the weight of
water flowing through the pipes in a given time, in the
range of 0.5 to 1 liter/sec. Error in the flowrate
measurements was kept at less than ±0.2% of the flowrate
by measuring at least 140 Kg of water for each calibration
point.
Temperatures in the scrubber system were measured by
copper-constantan (type T) thermocouples. The thermo-
electric voltages were recorded on a strip chart recorder
equipped with a potentiometric amplifier. The thermo-
couples were calibrated against a standard mercury bulb
29
-------
thermometer using constant temperature baths, and were
found to correlate well with the standard E.M.F.-temperature
relationships. Thus, the limits of error in measuring
temperatures were ±0.8°C according to the manufacturer's
specifications.
The scrubber gas line pressures were measured by
U-tube, inclined and well-type manometers, and "Magnehelic"
pressure gauges. Pressure drops across the liquor venturi
meters were measured with two-fluid (water and mercury)
well-type manometers.
Moisture content in the inlet gas stream to the
scrubber was measured by wet and dry bulb thermometers.
Gas stream downstream of the bottom sieve plate was con-
sidered to be saturated and the moisture contents were
determined from the temperature of the gas.
PARTICULATE SAMPLING SYSTEM
Two identical particle sampling trains were used to
measure the particulate loadings and size distributions
in the scrubber gas inlet and outlet streams simulta-
neously. The particulate properties were measured with
cascade impactors, followed by Gelman type A glass fiber
filters. The cascade impactors used were six and eight
stage, non-viable Andersen samplers and two University of
Washington, Mark IIIF in-stack impactors. The samples
were collected on aluminum substrates coated with high
vacuum silicon grease to prevent particle bounce. The
particulate loadings were rechecked by sampling with the
glass fiber filters only, for each operating condition.
The samples were drawn through two 1.3 cm diameter
sampling probes installed in the 3.7 cm sampling ports
in the scrubber inlet and outlet gas ducts. The sampling
30
-------
instruments, either the cascade impactors or the filter
holders, were located close to the sample ports. 1.3 cm
aluminum tubes were installed across the sampling instruments
so that the sample flows could bypass the instruments in
each train. The sample flowpaths were controlled with
3-way valves. Moisture from the sample gas was removed
by three cold impingers and a silica gel dryer located
downstream of the sampling instrument in each train.
The sampling probes, the sampling instruments and the
aluminum tubing to the cold impingers were heated with
insulated heating tapes controlled with variacs, to pre-
vent water condensation in the lines. The dry gas sample
flowrates were measured with a dry gas meter and a rota-
meter in each train. The sampling rates were controlled
by valves on the high pressure and bypass lines of the
oil less vacuum pumps. Prior to each run, the sampling
instruments were heated to the stack gas temperatures.
The sampling lines were also heated and flushed by drawing
gas through the bypass lines.
EXPERIMENTAL PROCEDURE
The auxiliary equipment and the measurement instru-
mentation were checked and started up prior to the start-
up of the scrubber. The liquor tanks were filled with
city water and the boiler and cooling tower operation were
started. The scrubber was started up by first starting
the water flowrate and adjusting it to the experimental
condition and then starting the scrubber blower to draw
filtered ambient air through the scrubber. After a steady
state was reached, the gas heater was fired and the air
was heated up to the desired temperature. Then steam was
introduced to attain the experimental moisture content in
the gas stream. Again, after a steady state was reached
31
-------
the particles were introduced to attain the experimental
operating condition. It normally took 60 to 90 minutes
to attain the experimental condition.
The flowrates , temperatures, pressures, moisture
contents and scrubber pressure drops were measured every
time a steady state was attained during the above pro-
cedure. These parameters were also measured just before
the start-up of particulate sampling, at least once during
the sampling or every thirty minutes, and just after the
sampling was completed. Sampling time in the scrubber
inlet duct varied from 15 minutes to 60 minutes depending
on the particulate loading, and the sampling rate ranged
from 0.68 to 1.0 m3/hr at the probe. The outlet sampling
time was from 2 to 3 times the inlet and the sampling
rate was about twice the inlet sampling rate to allow for
the lower outlet particle loadings.
When the total sampling time exceeded 30 minutes , the
sampling was interrupted and the coarse particles caught
in the cyclone and the impactor on the particle generator
were cleaned out. This was necessary to maintain a steady
performance of the particle generator. As the inlet and
outlet ducts were sampled simultaneously, small variances
in the particle generator performance did not significantly
affect the results. Also, since at least 90% of the par-
ticles were smaller than 2 ym, the sampling rates were not
adjusted to get isokinetic velocities at the probes.
The experimental conditions were found to stay very
stable once a steady state was reached. For all the
experimental runs reported, the temperature conditions
for the experiment varied within ±1.5°C during the ex-
perimental period.
32
-------
THE SPRAY FF/C SCRUBBER
Pilot Scale Scrubber System
The schematic process flow diagram of the FF/C scrubber
system is shown in Figure 4-7. Components of the scrubber
system are listed in Table 4-3. The scrubber had a design
capacity of 0.47 actual m3/sec (1,000 ACFM) inlet gas flow-
rate. As an illustration, flowrates in the lines shown in
Figure 4-7 are described in Table 4-4 when the inlet gas
stream to the scrubber is at 77°C, saturated with water
vapor. The FF/C scrubber and the particle generator are
described below.
FF/C Scrubber
Scrubber shell: 76.2 cm diameter x 3.8 m long made from
"Techite" fiber glass reinforced plastic sewer pipe,
with removable end flanges.
Spray arrangement: The scrubber consisted of three
sections, with a spray nozzle manifold in each
section. Each manifold had a capacity to spray
1.3 liters/sec of liquid with a sauter mean drop
diameter of 400 ym. The nozzles were located in
a grid pattern on the manifolds to obtain a uniform
distribution of spray in the scrubber cross-section.
The liquid was sprayed co-current in the direction
of gas flow. Thirty-two size 1/4B3 "Whirljet"
nozzles supplied by Spraying Systems Company, were
used on each manifold.
Liquid flow system: The system was specially designed
so that the cold scrubber liquid from the cooling
tower could be sprayed either through all of the
three manifolds in the scrubber, or through either
the first or the last manifold in the scrubber. In
the later cases, the scrubber was operated as a
three-stage scrubber by spraying the outlet liquid
33
-------
12
rHI
air, scrubber gas
water, slurry
steam
natural gas
I * TTT7
J
17
19
Figure 4-7 - Process flow sheet for the FF/C spray scrubbing system.
-------
Table 4-3. EQUIPMENT SPECIFICATIONS
Equipment:
a. Air prefilter
Four automobile air filters with a capacity of
8.5 m3/min air each
b . Air heater
Gas-fired air heater to heat air from 24°C to 100°C.
c. "Absolute" air filter
MSA "Ultra-Air" filter with a capacity of 0.476 m3/sec
of air.
d. Air, particulates and steam mixer
Disc and donut type mixer, 0.25 sec residence time.
e. Particle generator
To generate dry dispersed solid particulates with a -
mass mean diameter less than 2 ymA, up to 10y particles/cm-
of scrubber inlet air.
f. FF/C scrubber
Horizontal spray scrubber with a mesh type mist
eliminator.
g. Scrubber exhaust fan
Centrifugal fan with design capacity of 0.476 m3/sec
and AP of 50 cm W.C.
h. Pump
227 £/min and 15 m head (80 gpm and 50 ft head)
i , j, k. Pumps
114 £/min and 3.4 atm head, each. (30 gpm and
50 psi head).
1. Water cooling tower
A splash type, forced draft cooling tower. Cooling range
47°C at 190 £/min
m. Boiler water treatment
11.3 £/min ion exchanger.
n. Steam boiler
760 Kg/hr steam at 2.0 atm.
o. Cooling tower fan
4.25 m3/sec and 2.5 cm W.C. head
35
-------
TABLE 4-3 (continued)
p, q. Inter-stage liquor holding tanks.
200 liters capacity, each.
r. Scrubber liquor holding tank
450 liters capacity.
Scrubber liquor circuit
3.8 cm nominal diameter pipes, fittings, connections
and valves.
Steam circuit
5 cm, 3.8 cm and 2.5 cm diameter pipes, connectors,
valves, steam traps, 15.2 cm mist eliminator; all
insulated.
Scrubber gas ducting
15 cm diameter inlet duct with connectors, insulated.
15 cm diameter outlet duct with connectors, insulated
from scrubber outlet to sampling ports.
36
-------
Table 4-4 - STREAM FLOW RATES OF THE
SPRAY SCRUBBING SYSTEM
Stream
No.
1 $ 2
3 § 4
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Compositions
0.024 mole H?0/mole dry air,
air mixture
M it
0.696 mole H20/mole dry air,
air mixture
0.0483 mole H?0/mole dry air,
air mixture
0.00675 mole H20/mole dry air,
air mixture
Natural gas
0.154 mole H20/mole dry air,
air mixture
Steam
City water
Natural gas
City water
0.00675 mole H20/mole dry air,
air mixture
Process water
ii n
it n
it it
Temp.
°C
29
100
77
32
29
29
232
106
24
29
24
29
51
20
20
20
Vol . Flow
m3/sec
0.258
0.306
0.480
0.264
0.112
0.009
0.208
-
-
-
-
4.75
-
-
-
-
J?./sec
-
-
-
-
-
-
-
-
0.142
-
-
-
3.95
1.20
1.20
1.20
Mass Flow
Kg/hr
1,028
1,028
1,450
1,060
442 .8
71.2
514
442
509
9.6
26.8
19,800
13,975
4,525
4,525
4,525
%
Enthalpy
Kcal/Kg
9.65
42.5
206
26.8
9.65
-
190
644
24
-
24
9.65
51
20
20
20
air or water.
-------
collected in one section of the scrubber, into the
next section, and then into the third section in
series. Thus, the cold liquid requirement was re-
duced to one-third of the amount when cold liquid
was sprayed in all of the three sections. When the
cold liquid was sprayed into the first section, the
gas-liquid contact was co-current through the three
sections and when it was sprayed in the last section,
the contact was counter-current. Separation of
sprayed liquid from one section to another was
effected by sets of baffles, storage tanks and
pumps, as shown in Figure 4-7.
Entrainment separator: A wire mesh entrainment separator,
38.1 cm diameter, 15.2 cm long, made from 0.28 mm
stainless steel wire in a standard knit design with
98.2% voidage, was installed downstream of the third
spray section.
Particle Generator
The second particle generator described earlier, to
dry disperse titanium dioxide powder, was used for this
study. Due to the higher particle loading required, the
compressed air pressure upstream of the orifice was in-
creased to 1.0 atm, gage.
Instrumentation and Calibration
The inlet gas flowrate was measured with a standard
pitot tube located downstream of the air prefilter. The
scrubber system liquor flowrates, temperatures, line pres-
sures and moisture contents were measured with the same
instruments as described earlier for the multiple plate
scrubber. The measuring instruments were periodically
calibrated, as described earlier.
38
-------
PARTICULATE SAMPLING SYSTEM
Two identical particulate sampling trains, described
earlier, were used to measure the particulate loadings
and size distributions in the scrubber gas inlet and outlet
streams, simultaneously. Two University of Washington
Mark IIIF in-stack cascade impactors and Gelman type A
glass fiber filters were used to measure the particulate
characteristics.
The sampling procedure was also the same as described
earlier, except that the sampling elements were installed
in the respective stacks to minimize losses in the sampling
probes. The elements were also heated with electrical
heating tapes prior to sampling, to prevent condensation
in the sampling train lines.
EXPERIMENTAL PROCEDURE
The experimental start-up and shutdown procedures
were the same as reported earlier for the multiple plate
scrubber. The scrubber system flowrates, temperatures,
pressures and moisture contents were measured every time
a steady state was attained during the above procedure.
These parameters were also measured just before the start-
up of particulate sampling, at least once during the
sampling or every thirty minutes, and just after the
sampling was completed. The sampling times and rates
were the same as described earlier. The experimental
conditions were found to stay very stable, once a steady
state was reached. For all the experimental runs reported,
the temperature conditions for the experiment varied within
±1.5°C during the experimental period.
The methods of data analysis and calculation, and thus
the accuracy of measurements, were the same as described
earlier for the multiple plate scrubber.
39
-------
EXPERIMENTAL CONDITIONS STUDIED
During the experimental study, the scrubber performance
was studied for five scrubber operational modes. The ex-
perimental runs for one of the operational modes, with cold
water sprayed in all of the three sections of the scrubber,
were repeated to check the reproducibility of results. The
operating modes are described in Table 4-5 . During each
mode, scrubber performance was studied for a range of "q"',
varying from the cold runs to q' = 0.2.
METHODS OF ANALYSIS AND CALCULATION
As mentioned earlier, the particle characteristics
and the scrubber performance were measured by sampling
with absolute glass fiber filters and cascade impactors.
Information on total particulate loadings and thus the
overall scrubber penetrations, Pt, were obtained from
both of the above sampling apparatus. Sampling with the
cascade impactors provided additional information on the
particle size distributions, fractional loadings and thus
the fractional penetrations, and the inlet particle number
concentrations.
Particle Loadings and Overall Penetrations
The total particle loadings in the inlet and outlet
ducts were calculated in the following manner:
1. The sample flowrate was converted to the
standard conditions of 0°C and 76 cm of
mercury pressure.
2. Total weight gain on the sampling elements
was measured with an analytical balance,
Sartorius Model 2443; ±0.05 mg precision.
40
-------
Table 4-5. SPRAY SCRUBBER OPERATION MODES
Dust used:
Titanium dioxide, -16 mesh
n = 106/cm3
No.
1
2
3
4
5
6
Operating
Mode
One Stage
One Stage
One Stage
One Stage
Three Stages
Co-current
Three Stages
Counter-
current
Inlet Liquid
Flowrate per
Section(£/sec)
-1.0
-1.0
-0.76
-0.76
-1.0
-1.0
Drop Size
Small
(Mass mean
dia~350ym)
Small
Small
Large
(Mass mean
dia~450ym)
Small
Small
Notes
a. No . 2 was a
repetition
of No.l.
b . Liq. flow-
rate for
No . 3 was
reduced by
reducing
the no . of
spray noz-
zles .
c. Liq. flow-
rate for
No. 4 was
reduced by
reducing
the spray
pressure .
41
-------
3. The particle mass loading, c (g/DNm3), was
calculated from:
(total weight gain, g) (4-1)
c = — ~~
P (Sampling rate,DNm3/min) x (Sampling time,min)
4. The overall penetration was calculated from:
P?=^ (4-2)
°pi
where "c " and "c ." were the outlet and inlet
P° P1
particle loadings measured simultaneously for the
run.
Particle Size Distribution
The particle size distributions were measured gravi
metrically using the cascade impactor data. The particles
were assumed to have a log normal distribution. Cumulative
mass of particles collected on a stage and all the stages
below, including the absolute filter, were calculated as
a percentage of the total weight gain. The cut diameters
for the impactor stages were calculated from the sampling
rate, based on the manufacturer's specifications. The
geometric mass mean aerodynamic diameter, "d ", and the
c o
geometric standard deviation, "a ", were then determined
from a plot of the aerodynamic cut diameters against the
percent cumulative loading smaller than the cut diameters,
on a log probability paper.
Particle Number Concentration
Particle size distribution as measured by cascade im-
pactors was in terms of mass and it was necessary to con
vert this into a number distribution. For log-normal size
distributions it is simple to determine number mean diameter
42
-------
from mass mean diameter but this does not provide informa-
tion as to the number concentration. A method was developed
for computing the number concentration by multiplying a
hypothetical number concentration based on "d " by a cor-
rection factor which is dependent on "a ". The derivation
g
of this relationship is given below.
The total number concentration of particles, "n " , can
be computed from:
o dv
and ,
dv = n , no/cm3 (4-3)
t
d_n _ _ 3 , no . of particles
dv 4 irr 3 cm3 of particles *• '
P
where n = cumulative particle number concentration,
smaller than "r ", no/cm3
v = cumulative particle volume concentration,
cm 3 / cm 3
vf = total particle volume concentration
r = particle radius, cm
We define V = — = cumulative volume fraction,
dimensionless . And,
/
J dn d y dn dV (4-5)
dv t ° dv
The influence of particle radius can be related to
the mass mean radius by:
3
r
43
-------
where Rni = ratio of actual no. concentration for particle
radius "r ." to hypothetical no. concentration
based on "r ", dimensionless
r &
Subscript i is for radius "r -"
pi
Subscript m is for mass mean radius, "r "
r &
Thus, "R ", total number concentration ratio, is:
/
R R = actual no. concentration (4-71
ni n no. cone, based on r
Pg
This equation was integrated numerically for different
values of "a ". Note that for a log-normal distribution
the probability of the ratio of size to mean size is nor-
mally distributed. Therefore, "R " is defined by "a "
o
only. A plot of "R " versus "a " was thus obtained. From
O
the total particulate loading and "d " at scrubber inlet,
\r &
the hypothetical number concentration was calculated for
each run. Particle density of the iron oxide aerosol was
assumed to be 2.5 g/cm3 from Kotrappa and Wilkinson (1972),
and 3.0 g/cm3 for the titanium dioxide aerosol. Then, using
the experimental "a " , "n^1, the particle number concentra-
tion at the scrubber inlet, was determined from the plot.
These values of "ni" were checked periodically by using
the Gardner and Pollack Condensation Nuclei Counters. The
values were found to agree within a factor of 3.
Fractional Penetrations
The computation of penetration as a function of
particle aerodynamic diameter, or the fractional pene-
tration through the scrubber was done by a stepwise
graphical procedure. The procedure is based on the
following equations :
44
-------
Overall penetration can be defined as:
c
dc
pt o
pa
where "c ." is the total particle loading and "Pt(
the penetration for particle diameter, "d ", and
it is given by:
Pt
pa
r dcP~
Ld(dpa)J
dcp ~
_d(dpa)_
0
i
(4-8)
s
(4-9)
dc,
where
d(d.
is the slope of cumulative mass loading
pa)
less than "d " versus the aerodynamic particle diameter
curve, at "d a" , and equals "f(d &) " .
Thus, to determine the fractional penetration, the
following procedure was followed:
1. Cumulative mass loading for all the stages and
the filter, below the stage with a cut diameter
were plotted against "d " from the
of "d ",
inlet and outlet cascade impactor samples.
Slopes of the inlet and outlet plots above were
determined for several "d " values in the range
pa &
of 0.4 to 5 ymA. The fractional penetrations
were then determined and plotted from the ratio
of the slopes, as described above.
ACCURACY OF MEASUREMENT
Accuracy in measuring the particle size distributions,
fractional penetrations, overall penetrations and the
45
-------
inlet particle number concentrations from the cascade im-
pactor data depended on several factors. The precision of
the balance, impactor handling procedures, and measurement
of sampling rate influence the subsequent determination
of cut diameters. Subjective judgements of the persons
analyzing the data are involved when reading the graphs and
determining slopes. It is beyond the scope of this study
to determine the accuracy statistically. Best possible care
was taken in the laboratory, sampling and analytical proce-
dures to obtain accurate data and results. At least two
runs were made at every operating condition to duplicate
the data.
During the determination of overall penetrations using
"absolute" glass fiber filters, as least 5 mg of sample
was collected on each filter. Precision of the analytical
balance was ±0.05 mg. Thus, the maximum error due to the
weighing accuracy in determining Pt was:
c
Pi
dc dc
j— P P •
Thus, ^ = - -^ C4.10)
Pt cp cp.
o i
As the absolute values of the error were small compared
to the actual weights and as the error terms are additive,
Ac Acp.
Maximum error, Pt = + I (4-11)
c c
Po Pi
Thus, maximum error, Pt = ± °-' .2- = ± 4%.
46
-------
EXPERIMENTAL CONDITIONS STUDIED
During the experimental study, the scrubber performance
was studied for six scrubber operational modes. For each
operational mode- the scrubber performance was studied for
a range of the amount of water vapor condensed in the scrub-
ber per unit of dry air flow, "q™, varying from the cold
runs when particles were scrubbed from ambient air to q'~0.2
The operating modes are described in Table 4-6.
Table 4-6 MULTIPLE PLATE SCRUBBER OPERATIONAL MODES
No.
1
2
3
4
5
6
No. of
Plates
5
4
4
4
5
5
Inlet Liq.
Flowrate
U/sec)
0.64
0.64
0.64
0.38
0.38
0.38
Particle
Material
Iron Oxide
Iron Oxide
Titanium
Dioxide
Titanium
Dioxide
Titanium
Dioxide
Titanium
Dioxide
ni>
(no ./cm3)
low,~105
low,~105
high,~108
high,~108
high,~106
high,~106
Notes
During
No. 6,
steam
intro-
duction
was dis-
tributed
under
two
plates .
47
-------
CHAPTER 5
EXPERIMENTAL RESULTS AND DISCUSSIONS
Experimental and sampling procedures, and the methods
of data analyses and calculation of results are described
in the preceding chapter. During the experimental study,
scrubber performances were determined as fractional pene-
tration of particles (with respect to the aerodynamic
particle diameter) and the overall particle penetration
through the scrubbers. Since the scrubber inlet particle
characteristics (size distribution and number concentration)
were different for each run, the fractional penetrations
provide a common base for comparing scrubber performances
for different operating conditions. The scrubber operating
conditions and performance are tabulated, with the frac-
tional penetration plots for cascade impactor runs, in
Appendix 5.A for the multiple plate scrubber and Appendix
5.B for the spray scrubber experiments.
THE MULTIPLE SIEVE PLATE FF/C SCRUBBER
Results
The multiple plate scrubber was evaluated at six oper-
ating modes as listed in Table 4-6- For each operating
mode, the scrubber performance was measured for a range of
"q'" values. Effects of the following variables were also
determined:
1. Addition of a fifth plate.
2. Changing the L/G ratio by changing the inlet
liquid flowrate.
3. Distribution of vapor condensation on the
plates by distributing steam introduction
under two plates.
4. The effect of inlet particle number concen-
tration, "n.".
49
-------
As discussed in Chapter 3, particle growth and
diffusiophoresis are expected to contribute the most to
the enhancement of particle capture in the scrubber
during vapor condensation. Thus, the amount of vapor
condensed in the scrubber per unit of dry gas, "q'",
and the scrubber inlet particle number concentration,
"n.", are the significant parameters to determine the
enhancement of particle capture in the FF/C scrubber.
Penetrations, "Pt", for 1.0 ymA and 0.6 ymA particles
are plotted against "q"' in Figures 5-1 through 5-5 for
the scrubber operating modes studied. Data points on
these plots were read from the fractional penetration
plots in Appendix 5.A. These data points were found to
be scattered on "Pt versus q'" plots, possibly indicating
the effects of other parameters, such as "n.", the inlet
liquid temperatures and scrubber pressure drops.
DISCUSSION
Calvert and Jhaveri (1974) have summarized the high
points of the previously available data on FF/C scrubbing
on a plot of penetration versus the condensation or in-
jection ratio. On Figure 5-6, the plate scrubber perfor-
mance is similarly compared with the results of Rozen and
Kostin (1967), for 1.0 ymA particles. The following is
indicated by the plot:
50
-------
1.0
H
CJ
o
hH
E-
,-J
u
0.1
0.01
0.001
I I
0 ymA
O
o
G
0
. 6 ymA
1.OymA
O d =0.6 ymA, 5 plates
pa
O d =1.0 ymA, 5 plates
pa
D d = 1.0 ymA, 4 plates
pa
Refer to Tables 5.A.I and 5.A.25Fe203
i i
1 .1.1 I I I I I
0.01
0.1
,g/g
i.o
Figure 5-1 - Penetration versus condensation ratio, four
and five plates.
51
-------
1.0
2
o
I—I
E-
O
O
h—i
E-
0.4
0.1
E-
0.03
0.01
Theoretically
Predicted
Performance,
dpa=1.0
\
\
\r
\
O dpa =0.6 ymA
Q d =1.0 ymA
pa
Refer to Table 5.A.3 , TiO,
I L
U .
r.o
q', s/g
Figure 5.2 - Penetration versus condensation ratio, four
plates
52
-------
1.0
H
u
0.1
H
W
w
_J
u
i — i
H
0.01
T I
Theoretically
Predicted
Performance,
d =1.0 ymA
pa
\
0
0.6 ymA
1.0 ymA
O d =1.0 ymA
w pa M
D dpa =0-6 ymA
Refer to Table 5.A.4, TiCU, Low L
. I , : , • • , I , III
0.01
0.1
0.5
q' g/g
Figure 5.3 Penetration versus condensation ratio,
four plates.
53
-------
2
o
o
1—I
H
2
W
U
i — i
E-"
1.0
0.1
0.01
o
•Theoretically
Predicted
Performances,
dpa=1.0
O d =0.6 ymA
pa
D d.
pa
1.0 ymA
I —
O
O
0.6 ymA
1.0 ymA
Refer to Table 5.A.5, Ti02, Low L
i i i iii ii I i
0.01
0.1
0.5
q', g/g
Figure 5.4 Penetration versus condensation ratio,
five plates
54
-------
0.03
0.01.
0.03
0.05
0.1
0.2
Figure 5.5
q', g/g
Penetration versus condensation
ratio, five plates, distributed
steam inlet.
55
-------
H
U
O
I—I
E-i
cx
W
1.0
0.5
\ Note: Numbers on curves
\ correspond to references.
in Table S-l.
1. ni = 10'
0.1
0.05
0.01
O Reference #7
Table 5-1
0.01 0.05 0.1 0.5 i.o
CONDENSATION OR INJECTION RATIO, q', g/g
Figure 5-6 -FF/C scrubber performance comparison
5.0
-------
Table 5-1. FF/C scrubber performance comparison
Ref .
1
2
3
4
5
6
7
Experimental
Studies
Rozen and
Kostin (1967)
present
investigation
present
investigation
present
investigation
present
investigation
present
investigation
present
investigation
Scrubber
Type
Alternate ho't
and cold sieve
plates
Five sieve
plates
L = 0.64 a/sec
Four sieve
plates
L = 0.64 £/sec
Four sieve
plates
L = 0.64 a/sec
Four sieve
plates
L = 0.38 £/sec
Five sieve
plates
L = 0.38 a/sec
Five sieve
plates
L = 0.38 a/sec
Steam intro-
duction
distributed
under two
plates
d
Pg
(ym)
0.3
0.55
0.55
0.5
0.5
0.5
0.5
Particle
Material
Oil
Black
Iron
Oxide
Black
Iron
Oxide
Titanium
Dioxide
Titanium
Dioxide
Titanium
Dioxide
Titanium
Dioxide
ni
(no ./cm3)
10s 108
~3 x 105
~3.6 x 105
3 x 10s
-7.2 x 109
most- 108
2.4 x 107
-8.8 x 108
most-108
5 x 105
-1.7 x 107
most~106
3 x 105
-3.4 x 106
most~106
57
-------
1. Particle penetration depends heavily on the con-
densation ratio, "q"'. Calvert et al. (1973)
have shown that "q1" is sufficient to define
particle deposition rate, without regard to
"n^", if there is no condensation on the particles.
2. A comparison of curve 5 with 6 and curve 2 with
3, indicates that for the same "q'" and comparable
operating conditions, addition of a fifth plate
significantly improved the performance of the
multiple plate scrubber. During runs for curves
5 and 6, the gas flowrate at the scrubber inlet
was maintained approximately constant but the
particle concentration was higher for curve 5.
During runs for curves 2 and 3, the overall scrub-
ber pressure drop was maintained approximately con-
stant by decreasing the gas flowrate for the five
plate scrubber so plate hydrodynamics may have
changed. The improvement by the addition of a
fifth plate is expected to be mainly due to
particle growth, although particle concentration
and hydrodynamic effects may also be involved.
3. A comparison of curves 4 with 5 indicates that for
the same "q'" and comparable operating conditions,
a decrease in the L/G ratio did not significantly
affect the performance of the scrubber. The L/G
ratio was changed from 3.8 £/m3 (29 gal/MCF) to
2.28 £/m3 (17 gal/MCF), by reducing the liquid
flowrate. Both of the L/G ratios were within the
operating range on the plates as shown in Figures
4-2 through 4-6. This observation was consistent
with the observations of other investigators as
reported by Semrau and Witham (1975) for orifice
type scrubbers. It should be noted, however,
that the scrubber performances are compared at
the same "q"'. Thus a lower L/G ratio with re-
58
-------
circulated liquid would require a larger cooling
range in the liquid cooling system.
A comparison of data when steam was injected at
two points in the scrubber (reference #7), with
curve 6, shows that for the same "q1" and com-
parable operating conditions, the scrubber per-
formance improved significantly when the vapor
condensation was distributed over two sections
of the multiple plate scrubber. Calvert et al.
(1973) and Calvert § Jhaveri (1974) have reported
theoretical studies of the effect of distributing
vapor condensation in multiple sections of multi
stage FF/C scrubbers. An experimental study of
this effect was reported by Rozen and Kostin (1967).
These studies indicated that irrespective of the
particle collection mechanisms effective in a
scrubber, distribution of vapor condensation
along the scrubber results in higher particle
collection efficiency. As the particles used in
this study were wettable, the higher collection
efficiency is expected to be due to the decrease
in "n." (due to particle collection on the bottom
three plates), before steam was injected under
plate 4. Thus, the amount of vapor available for
condensation per particle, "q", is higher for
plates 4 and 5, resulting in better collection
efficiency.
A comparison of curves 2 and 6 and curves 3 and 4
shows that for the same "q1" and comparable operating
conditions the scrubber particle collection
efficiency was higher for lower "n.". This
effect can be shown theoretically to accompany
condensation on particles and their growth at
the expense of the water vapor concentration in
59
-------
the gas. A higher particle number concentration
requires higher amounts of condensed vapor to
grow, effectively reducing the diffusiophoretic
sweep velocity to deposit them. Also, the fewer
the particles which share a given quantity of
condensation, the larger they will grow and the
easier they are to collect.
Comparison with Theoretical Predictions
A mathematical model of an FF/C sieve plate scrubber,
developed and experimentally verified by Calvert et al.
(1973) was extended to predict the performances of the
multiple plate scrubber. For the purpose of comparison
with the experimental results, the inlet particle diameter
was assumed to be 1.0 ymA. The model is described in de-
tail in Chapter 6. A spray scrubber model is also described
in Chapter 6.
60
-------
THE SPRAY FF/C SCRUBBER
Results
The spray scrubber was evaluated at five operating
modes, as listed in Table 4-5, For each operating mode,
the scrubber performance was measured for a range of "q"'
values. Effects of the following variables were also
determined:
1. The amount of cold water sprayed in the scrubber
was varied. Effect of reducing the cold water
spray in a 3:1 ratio was studied by operating the
scrubber in a three-stage mode.
2. The L/G ratio was controlled by changing the inlet
flowrate.
3. Liquid drop size distribution was changed at the
same L/G ratio.
4. Overall gas-liquid contact mode was altered by
operating the three stage scrubber in the co-cur-
rent or counter-current mode.
As particle growth and diffusiophoresis are expected
to contribute the most to the enhancement of particle
capture in the scrubber, the effects of "q'" and "n." on
"Pt" were determined. "Pt" for 1.0 pmA and 0.6 ymA par-
ticles are plotted against "q™ in Figures 5-7 through
5-12 for the operating modes studied. Data points on these
plots were read from the fractional penetration plots in
Appendix 5.B. Again, the data points were found to be
scattered, possibly indicating the effects of other para-
meters, such as "ni" and the inlet liquid temperatures.
DISCUSSION
The spray scrubber performance is compared with the
results of Lancaster and Strauss (1971) and with some plate
scrubber data on Figure 5-13, a plot of particle penetration
61
-------
§
2
O
W
1.0
0.5
0.1
0.05
0.01
O dpa = 1.0 ymA
Ad =0.6 ymA
pa
Refer to Table 5.B.I
in r
A
0.6 ymA
1.0 ymA
1,11
0.01
0.05
0.1
0.5
q', g/g
Figure 5-7 Penetration versus condensation ratio
one stage spray.
62
-------
H
U
PL,
*V
O
i—i
H
H
2
W
U
i—i
H
f*
<
P-i
1.0
0.5
0.1
0.05
0.01
Ad =0.6
*-* pa
O d =1.0
pa
Refer to Table 5.B.2
1.0
, I I
0.01
0.05 0.1
0.5
q', g/g
Figure 5-8 Penetration versus condensation ratio,
one stage spray.
63
-------
0.3
0.2
2:
o
U
O
0.1
to
w
0.05
0.02
I
A
d =0.6 ymA
pa
O dpa = 1'° ymA
O
O
Refer to Table 5.B.3, low L
i i i i i i I i I
0.03 0.05
0.1
' ,g/g
0.2 0.3
Figure 5-9
Penetration versus condensation
ratio, one stage spray.
64
-------
1.0
o
t—H
H
C_>
<
Pi
H
W
Z
W
PH
CJ
PH
0.5
0.2
0.1
0.05
0.6 ymA
A
d =0.6 umA
pa
d = 1.0 ymA
Refer to Table 5.B.4, low L, large
i iii i i i i I i
Q
0.015
0.03 0.05
0.1
0.2 0.3
Figure 5-10
Penetration versus condensation ratio,
one stage spray.
65
-------
1.0
0. 5
2
O
U
2
O
i—i
E-i
§0.1
2
^0.05
Pi
O d
A
pa
pa
I I I I
ymA
1.0
1.0 ymA
0.6 ymA
Refer to Table 5.B.5
0.01
0.05 0.1
q', g/g
0.5
Figure 5-11 Penetration versus condensation ratio,
three stage co-current spray.
66
-------
1.0
0.5
H
U
<
Pi
2
0 0 2
I—i \J , L,
Pi
H
W
OH
H
Pi
<
fX
0.1
0.04
O d =1.0 ymA
pa
Ad =0.6 ymA
^ pa M
Refer to Table 5.B.6
i i i i i i i
A
O
I
I
0.02
0.2
0.05 0.1
q', s/g
Figure 5-12 - Penetration versus condensation ratio,
three stage counter-current spray.
0.4
67
-------
1.0
0.5
O
i—i
H
CJ
<
&,
PH
0.1
Pi
2
Q-<
w
u
I—I
Pi
0.05
0.01
Lancaster § Strauss (1971)
Numbers refer to Table numbers
in Appendix 5-B.
i . . , , , , , I , I
0-01 0.05 o.l 0.5
CONDENSATION OR INJECTION RATIO
(g vapor/ g dry gas)
Figure 5 -13 Comparison of FF/C plate and spray
scrubber results for 1 ymA particles
68
-------
versus condensation or injection ratio, for 1.0 umA par-
ticles. The following is surmised from the plot:
1. Particle penetration depends heavily on the
condensation ratio, "q"1. Calvert et al. (1973)
have shown that "q"' is sufficient to define
particle deposition rate, without regard to
"n-", if there is no condensation on the par-
ticles .
2. A comparison of curves 1 and 2 shows that the
scrubber performance could be reproduced, if
operated at nearly the same conditions, thus
reinforcing the validity of experimental data
and techniques.
3. A comparison of curves 1 or 2 and 3 indicates
an apparent anomaly. The amount of water
sprayed into the scrubber during runs indicated
by curve 3 was about 251 less than that sprayed
for the runs indicated by curves 1 and 2. Thus,
curve 3 may be expected to have higher pene-
trations. This effect may be due to better
liquid utilization when the water sprayed in
was less, resulting in a higher collection
efficiency of large particles by impaction.
(Note that particle growth is higher at higher
"qf" values.) Spray drop diameters during all
the runs were the same. The better liquid
utilization may be due to less drop coalescence
and lesser wall losses when the liquid flowrate
was less. This effect bears further experi-
mental investigation.
4. A comparison of curves 3 and 4 illustrates the
effect of spray drop diameter. Although the
liquid and gas flowrates were identical for
these runs, the spray drop volume mean dia-
69
-------
meter for curve 4 was about 1 5 times the dia
meter for curve 3. Thus, the particle collec-
tion by impaction and the spray drop space
density (number of drops in a unit scrubber volume)
are lower for curve 4, resulting in the high pene-
trations .
5. A comparison of curves 1 or 2 (1 stage) with 5
(co-current), shows that the particle penetrations
are higher when the amount of cold liquid sprayed
is reduced by about 67% although the total liquid
spray rate is the same. In both the operating
modes cold liquid was sprayed in the section where
the gas enthalpy and vapor content were highest.
Thus, the highest possible temperature and vapor con-
centration gradients were imposed in this section.
The slightly higher penetrations for curve 5 indi
cate that although most of the particle growth oc-
curred in the first section of the scrubber, FF/C
mechanisms were also effective in the second and
third sections.
6. A comparison of curves 5 with 6 (counter-current)
indicates the importance of causing particle growth
quickly in a FF/C scrubber. The only difference in
scrubber operation was that for curve 5, the coldest
water was sprayed into the gas with the highest
enthalpy and water vapor content; while for curve 6,
the hottest water was sprayed into this gas in the
first section, thus providing a more uniform
distribution of gradients along the length of the
scrubber. Curve 5 penetrations are lower, probably
due to more particle growth for co-current contacting
70
-------
CHAPTER 6
FF/C SCRUBBER PERFORMANCE PREDICTION METHODS
The prediction of particle collection performance for
FF/C scrubbers in advance of experiments can be done by means
of theoretically based mathematical models. The approach
used is to derive particle collection equations which account
for all of the applicable unit mechanisms, which could be
active in the scrubber. Such models are then used to pre-
dict particle collection in the two FF/C scrubbers descri
bed earlier. The predicted performances are compared to the
experimental results.
Experimental results for the multiple plate FF/C scrub-
ber compared well with the predicted values. The predicted
performances of the horizontal spray FF/C scrubber, however,
compared well with the experimental results only in a small
range of particle size. Thus, a set of empirical design
equations was developed for the spray scrubber by fitting
curves through the experimental results. Limitations on
the use of these models for predicting performance of the
FF/C scrubbers are discussed.
THE MULTIPLE SIEVE PLATE FF/C SCRUBBER
A mathematical model of an FF/C sieve plate scrubber,
developed and experimentally verified by Calvert et al.
(1973) was extended to predict the performances of the
multiple plate scrubber. Particle collection on a sieve
plate was represented by the unit mechanism of transfer
from bubbles. The model incorporates the following
phenomena:
1. Heat transfer between bubbles and liquid.
2. Heat and mass transfer between bubbles and
particles.
71
-------
3. Particle deposition by:
A. Impaction during bubble formation
B. Diffusiophoresis
C. Thermophoresis
D. Centrifugation during bubble rise
The following general assumptions were made:
1. Gas bubbles are spherical, of constant diameter
(d, =0.4 cm), and perfectly mixed internally
(except for the interfaces).
2. Gas properties are as for air and water vapor.
3. Foam density is constant throughout the foam
layer on the plate.
4. Liquid bulk temperature is constant throughout
the foam although the liquid-bubble interface
temperature can vary. The bulk temperature is
the average of inlet and outlet liquid tempera-
tures .
5. Particles are wettable, insoluble spheres.
6. Condensation on particles can occur whenever
the saturation ratio is 1.0 or larger.
7. All the particles are subjected to condensation
and growth.
Several transfer phenomena contribute toward the
deposition of particles from the gas stream on a sieve
plate. To determine the overall particle collection,
equations were developed for each of the significant trans-
fer phenomena and then combined for the sieve plate. Since
these phenomena are dependent on the magnitudes of the
liquid and gas phase conditions at each point along the
sieve plate column, these conditions then need to be deter-
mined for use in the design equations. Detailed deriva-
tions of the equations listed below are described by
Calvert et al. (1973) and are omitted here for brevity.
72
-------
Particle Deposition
Inertial Impaction During Bubble Formation
During the formation of bubbles on a sieve plate,
contact between gas and liquid phases is due to the jets
of gas emerging from the perforations and impacting on
the liquid. Particles are thus deposited on the liquid
surface by inertial impaction. Particle collection can
be determined from:
40 F2dpc'
where F = foam density, volume fraction liquid
d = particle diameter, cm
p - particle density, g/cm3
C' = Cunningham slip correction factor
u, = gas velocity in the perforation, cm/sec
y^ = gas viscosity, poise
d, = diameter of perforation, cm
Pt, = penetration of particles of diameter d ,
for collection during bubble formation
Equation 6-1 was experimentally verified by Taheri and
Calvert (1968) for hydrophilic particles and for 0.38 <_
F <_ 0.65. In the normal operating range of the sieve
plate, 50? of particles with the diameter of approximately
2.5 ymA would be deposited due to this phenomenon. However,
the particle deposition drops sharply as the diameter
decreases. For hydrophobic particles, experimental results
reported by Taheri and Calvert (1968) can be used, although
a generalized design equation was not developed by them.
B. Particle Collection on the Sieve Plate
The total particle flux from the gas to the liquid
is defined as the sum of fluxes due to diffusiophoresis ,
73
-------
thermophoresis and centrif ugation. Particle deposition
by Brownian diffusion was neglected as it is not very
effective for particles > 0.1 ym diameter. Thus,
N, - Nn + NT + Nf fe' Prides \ (6.2)
i L 2
cm-sec
and' NS = upsnp
where u = overall deposition .velocity cm/sec
Ps . ,
. . . . no. particles
n = particle concentration, - £ — ; -
P cm3
For a spherical bubble of radius "rb", the rate of change
of particle concentration is:
dn / 7\ /3n \
_X =(-L\N -UJilu (6-3)
dt T) S r Ps
where ups = UpD + upT + upC = sum of ies (6-4)
Thus, the penetration for a period = At is:
Pt (dp) = exp [- -L(Ups)At] (6-5)
Dif fusiophoretic deposition velocity for air and water
system can be expressed as:
0.85 RTGk« (pG-pLi)
UpD = - - 7\ - ' - (cm/sec) (6-6)
U-PGJ
where pQ = partial pressure of the diffusing component,
water vapor in the gas phase, atm
PLI = Partial pressure of water vapor at the gas-
liquid interface, atm
Tg = gas phase temperature , °K
R = gas constant
74
-------
k' = mass transfer coefficient, gas to liquid,
b
g-mole
cm2 -sec-atm
Thermophoretic deposition velocity for air and water system
can be expressed as:
upT « 6.14 x 10- C' hG TG (TG-TLi) (6-7)
where TT . = temperature at the gas-liquid interface, °K
Li 1
Centrifugal deposition velocity in the foam can be expressed
as :
d2p C'u 2
u = JO - L. (6-8)
PC 18 ^b
and for bubble radius, rb=0.2 cm, tangential velocity,
u =bubble rise velocity=20 cm/sec;
d2p C'
u = 1.85 x 108 -EJ2 — (cm/sec) (6-9)
PL TG
To determine particle deposition from the above equa-
tions, the particulate, gas and liquid conditions at each
point along the rise of the bubble in the foam need to be
determined. In the model discussed here, the tangential
velocity of the bubble is assumed to be equal to the velo-
city of rise. Thus, the bubble completes one rotation per
rise of one bubble diameter. For computational purposes,
the rise of one bubble diameter is used for a differential
increment in distance and time on the sieve plate. The
gas and liquid conditions along the foam height are deter-
mined from heat and mass transfer in bubbles. Particle
growth is computed from a similar treatment for the par-
ticulate-gas system in the bubbles.
75
-------
Heat and Mass Transfer in Bubbles
The vapor-liquid equilibrium relationship for water
can be approximated within a few percent by:
pe = exp (13.64 - -5>1*1Q3) atm (6-10)
where p = water vapor partial pressure in equilibrium
at T°K
Temperature and vapor pressure at the bubble interface are
determined by using Equation 6-10 in conjunction with the
equation for the overall energy balance at the bubble inter-
face :
kGLM tPG-PLiJ hL ^Li-V hG CTLrV = ° (6'n)
where LM = latent heat of vaporization for water,
cal/g-mole
h, = liquid phase heat transfer coefficient,
cal/sec-cm2-°K
Tj = temperature of liquid bulk, °K
hp = gas phase heat transfer coefficient,
cal/sec-cm2-°K
The gas temperature, composition and flowrate, and the
liquid temperature change along the foam height due to vapor
condensation and sensible heat transfer. The vapor conden-
sation can be expressed as:
MT = M + M. g/m01 "2° VaP°r (6-12)
P D cm2 of plate area
where MT = total vapor condensed
M andM^ = vapor condensed on the particles and liquid
respectively
76
-------
The overall transfer rate can then be expressed in
the form of a difference equation for an increment as:
il CrJ-rJ) npVZ . k-ab (pG-pLi)AZ ^ (6-15)
where a, = bubble surface area per volume of foam
= yh (/) ™1
b M, cm3
D
r9,r, = the final and initial particle radii in
Li -L
the increment, respectively, cm
n = number concentration of particles in gas,
no /cm3
V, = volume fraction bubbles in froth, cm3/cm3
AZ = height of bubble rise, cm, in time "At", sec
d, = bubble diameter, cm
The change of gas temperature can be expressed as :
GCPMATG = hGVTLi-VAZ + AMPLM ~~- C6"
F cm2-sec
where CpM = molal heat capacity of gas, cal/mol-°K
G = molal gas flowrate per unit area of plate,
g-mol/cm2 -sec
Particle Growth
The rate of change of particle radius can be expressed
as :
cm
pM sec
77
-------
2D P
where k' = - - - — S m° - = mass transfer
Pb RT^d-puT,, cm2-sec-atm ,-r- - . .
G pFBM coefficient, gas to
particle
Dp = diffusivity, cm2/sec
P = total pressure, atm
pRM = mean partial pressure of non-transferring
gas , atm
p . = vapor partial pressure at the particle
interface, atm
p,, = molal density of water, e - > —
M 3 'cm3
Thus , particle growth over a finite period can be expressed
as :
2D P(p -p )At
r2-r2 = — £ - ^— Ei - cm2 (6-16)
"p ." can be determined from Equation (6-10) if "T i"
is known. For air-water system and small increments in
temperatures:
T . - T » 0.925 (T* Tr) (6 17)
pi b b
where T* = saturation (equilibrium) temperature
corresponding to the partial pressure
of water in the bulk gas, "Pr".
A computer program was developed to solve the mathe-
matical model comprised of Equation 6-2 through 6-17 listed
above, for predicting particle collection in a sieve plate.
Particle collection during bubble formation was not in-
cluded in the program as it depends only on the initial
conditions. The computer program is listed in Appendix
6.A. Input parameters are entered in two sets in the
78
-------
program to provide flexibility. The first set of para-
meters include :
TIN - the inlet gas temperature
PIN - water vapor partial pressure in the inlet gas
TLB - average liquid bulk temperature on the sieve
plate
RP - particle radius in the inlet gas
CNP - inlet particle number concentration, no /cm3
The second set of inlet parameters include:
GM - total gmoles inlet gas/sec-cm2 plate area
RK - 2 k'G pBM/P, at inlet conditions
RH - hQ (TG) 1/2 , at inlet conditions
RKL - 2 (RK) x 10VhL
RHL - (RH)/hL
DB - diameter of the bubble, cm
VELB- velocity of bubble rise, cm/sec
VB - volume fraction bubbles in froth
DZ incremental distance for difference calculations
THT incremental time corresponding to DZ
NI - number of increments in the calculation = foam
height/DZ
Values for the second set of inlet parameters are listed
in Appendix 6.A as examples only. Results from the pro-
gram are listed in two formats, as actual end values and
in a graphical form, illustrating results at each com-
putational step. End values of the gas temperature, vapor
partial pressure, particle radius and the overall penetra-
tion are printed out. The graphical print-out denotes
values of the following four parameters at each increment
in THT:
g
S' = T = one half °f the saturation ratio in the gas phase
T -T
Ti G L present AT
T-. TT inlet AT
79
-------
p _ n , _ present particle concentration
™ po inlet particleconcentration
, _ _ inlet particle radius
r p rpo/r ~ present particle radius
By definition, the above four dimensionless parameters
range in value from 0.0 to 1.0 and are plotted on the "Y"
axis. Normalization of the parameters in this manner
simplifies the "scaling" required for machine plotting.
The "X" axis denotes time in increment of THT.
Comparison with Experimental Results
To validate the above model, experimental conditions
for three modes of multiple-plate FF/C scrubber operations
reported in Chapter 5 were used to predict collection of
1.0 ymA particles. These compared well with the experi
mental results. Based on the experimental results of
Calvert et al. (1973), the following values were assumed:
-, , _ 2.09 x 10 ^ P gmole/cm2-sec-atm
G " PBM
hr = 2.48 x 10"2 T ~°-5cal/sec-cm2-°K
u b
hL = 0.01 cal/sec-cm2-°K
F =0.4
If there were no heat loss from the column, the gas and
liquid temperatures predicted by the model using the above
values would agree with the experimental data. However,
since there were heat losses from the column, the above
assumptions should be refined with careful experimental
studies of plate hydrodynamics and transfer properties.
Predictions of the particle collection in the multiple
plate column were made by a plate-by-plate procedure start
ing with the bottom plate. Using experimental data, per-
formances were predicted for the following operating modes
80
-------
of the scrubber:
1. Five plates, high n., low L/G
2. Four plates, high n-, low L/G
3. Four plates, high n., high L/G
These modes were selected because the "n." values corres-
ponded to the practical emissions reported for industrial
pollution sources.
The predicted performances are plotted as penetration
versus condensation ratio, on Figures 5-2, 5-3 and 5-4.
Comparison of the predicted performance with the experi
mental results for d =1.0 ymA particles indicate that
both the curves follow the same trend, or have comparable
slopes on the log-log paper. This suggests that the parti
cle collection mechanisms were predicted correctly, al
though they differed in magnitude. Predicted performance
of the five plate scrubber correlated well with the experi
mental results. However, predictions for the four plate
scrubber operations were biased towards lower penetrations.
In its present form, the computerized model has two
main limitations. The equations as used were derived for
air-water system at the total pressure of 1 atm. As the
pressure drop across a FF/C scrubber is low, assuming
atmospheric pressure does not introduce any significant
error. However, if the gas and liquid properties are sig-
nificantly different from the air-water system, the program
must be changed accordingly, starting from the generalized
equation described in the text. The second limitation is
that only one particle size can be input in the program.
Thus, if a relationship between" Pt" as a function of"d "is
desired, the program has to be manually run for the desired
number of particle diameters. However, with a minor pro-
gram modification and additional input for particle size
distribution, the program can be used to develop the "Pt"
versus "d " relationship automatically.
81
-------
THE HORIZONTAL SPRAY FF/C SCRUBBER
Particle collection in the FF/C spray scrubber is
affected by inertial impaction, diffusiophoresis, and
thermophoresis. During this study our approach was to deve-
lop equations for particle collection by inertial impaction,
and use them in conjunction with the mathematical models for
particle growth and collection by flux forces as described
by Calvert et al. (1973).
Particle collection efficiency by inertial impaction
in a spray scrubber can be predicted by means of methods
described in the "Scrubber Handbook" (Calvert et al. 1972),
for cases where the drop velocity is constant, or may be
considered so. When the spray is generated by high pres-
sure nozzles, the drop velocity is initially very high
compared to the terminal settling velocity. Therefore
the collection efficiency of the drop decreases greatly
as the drop slows down and the overall collection by the
drop is the integrated effect of efficiency over the drop
traj ectory.
Walton and Woolcock (1960) studied this problem in
connection with the use of pressure sprays to control coal
mine dust. They computed the relationship between collec-
tion efficiency and the distance traveled by a drop for
several particle sizes and drop diameters. Figure 6-1 is
taken from their paper and shows these relationships as
predicted for coal dust (density = 1.37 g/cm3). Drop velo-
city is also plotted so that one can find efficiency as
the drop accelerates from a given initial velocity.
The relationships given in Figure 6-1 can be used to
predict the collection efficiency of a spray scrubber mak-
ing the following assumptions which we used in our model:
82
-------
1. Assume that the particle concentration is
uniform as the aerosol enters a spray stage,
that it decreases exponentially as it passes
through the stage, and that it is completely
mixed (i.e. uniform concentration) before
entering the next stage.
2. Assume that collection is by inertial im-
paction on the front of the drop only. This
is the same as Walton and Wool cock assumed.
3. Assume that the percent of the gas area
covered by the sprays (co-current) varies
as shown in Figure 6-2, which is based on
the arrangement of nozzles used in our pilot
plant spray scrubber.
4. Assume that the drop diameter is uniform.
Based on the above assumptions, the equations des-
cribing the multi-stage, co-current spray scrubber are
as follows:
Volume of gas which is swept clean of particles per
unit of liquid volume is:
V = (J^-) R,E x 10" ,(m3/&)
s 4rd d
where
V = Gas volume swept clean per liter of drops, m3/£
r, = Drop radius, cm
Rj = Drop range (i.e., distance traveled), cm
E = Average particle collection efficiency over
range "Rj", fraction
If the collection of particles is a first order
process,
PtA = exp - (V '
83
-------
50
10
0
o :.5 s.o 7.5 10
HORIZnVTM, mSTANCr FROM SPRAY MAN I FOLD ,cm
Figure 6-2 - Scruhher area cohered hy sprays.
-------
where L/G = Liquid to gas flow ratio, (I H20/m3 gas)
Pt. = Penetration per stage for a given particle
diameter, fraction
The penetration for "N" stages is:
Pt = fPt ")^
rzN ^V
The average efficiency was computed by plotting the
product of efficiency times fraction of gas flow covered
by sprays, versus the drop range (distance traveled) and
then doing a graphical integration. These plots were
made for several particle sizes and for an initial velo-
city of 20 m/sec and drop diameters of 0.05 cm and 0.03
cm. These conditions correspond to our pilot plant runs
at 2.7 atm (40 psig) spray nozzle pressure. We also
assumed that the maximum drop range is 100 cm, based on
scrubber size.
The results of the computations for a liquid to gas
ratio of 2.35 £/m3 (18 gal/MCF), corresponding to the
flow rate per stage in our pilot plant runs, and for
three stages are shown in Figure 6-3 for 0.05 cm drops
and Figure 6-4 for 0.03 cm drops. Because of the differ-
ence in slope between the predictions and the experimental
data we explored the influence of decreasing the amount
of effective spray, assuming that there is agglomeration.
The results are shown in Figures 6-3 and 6-4.
As can be seen, the predictions are fairly close to
the data at the cut diameter (0.5 Pt) but not for other
particle diameter. We have not yet been able to devise
a model that will account for this discrepancy. It is
quite possible that lower penetration for particles smaller
than 1.0 ymA is due to their collection on the backs of
the drops. However, we do not yet have a predictive cor-
85
-------
1.0
0. 5
0.4
0.3
0.2
0.1
1 1 1 — i — r~r- 1 1 1 —
123
- \ V -.
\ \\ -
V :
i \ \
\\
- Curve L/G,£/m3 1 \ »
1 2.35 1 \\
- 2 1.0 , ,,
3 0.7 | \\
i i i i i i 1 i
0.3 0.5 1.0 2.0
Figure 6-3. Spray scrubber
penetration predictions for
500 ym drop diameter.
1.0
0.5
0.4
0.3
0.2
0.1
_ ' ' ' ' ' ' 1 ' 1
123
- \ X\ -
\ \\
\ \\
- \ \\ -
\ \\
- Curve L/G,£/m3 \ \\ ~
1 2.35 \ \\
2 1.0 \ \ \
3 0.7 \ \\
i i i i i i 1 i I
0-3 0.5 1.0 2.0
Figure 6-4. Spray scrubber
penetration predictions for
300 ym drop diameter.
86
-------
relation to account for this effect. Since a design
equation for particle collection by inertial impaction
could not be validated by our data, a model for FF/C spray
scrubber was not developed.
In order to obtain design equations for scale-up pur-
poses of FF/C spray scrubbers similar to the scrubber tested
in this study, a curve fitting technique was used. Scrubber
performance data for 1.0 ymA particles are plotted in Fig-
ures 6-5 through 6-7 , as particle penetration versus the
amount of vapor condensed per particle, "q". This value
was used instead of "qtf'as it normalizes the effect of
particle number concentration, "n.". Again, scatter in
the data was observed, possibly due to the effects of inlet
liquid temperatures and the actual amount of vapor condensed
on the particles. The range of scatter around the least
square fit was within ±50%.
Curve fitting procedures were employed on each hori
zontal spray FF/C scrubber data set to obtain the functional
relationship between "Pt" and "q". The initial step is the
assumption that the relationship between "Pt" and "q" can
be represented as a power function:
Pt = AqB
or synonymously as the straight line equation:
In Pt = In A + B In q
The method of least squares was utilized to obtain the
best straight line curve fit through the experimental set
of paired variables, "In Pt" and "In q", where "In q" was
regarded as an ordinary variable measured without appre-
ciable error, and "In Pt" as the random variable.
87
-------
00
00
n. 01
O See Table 5.B. 1
A See Table 5.B.2
O See T
A See Table S.R.4
10
10 LL 10 "
g vapor condensed penetration
Figure 6-5. Experimental 1.0 ymA particle penetration
for spray scrubber.
in"11 lei'10 l
q, g vapor condensed penetration
Experimental 1.0 iiirtA particle Penetration
for spray scrubber.
0.01
O See Table 5.R.6
A See Table 5.B.5
I
10
-12
Fi gure 6 - 7.
10 " in'1" in'
q, g vapor condensed penetration
Txperimental 1.0 gmA particle penetration
for spray scrubber.
-------
After the determination of the constants "A" and "B"
for the straight line equation, the percent error for each
data point was calculated. Those that indicated appre-
ciable error (251 or greater) were eliminated (these points
are shaded on the plots) and the least square straight
lines were redetermined for the remaining number of data
points. As shown in Table 6-1, four data points were thus
not included in the determination of the least square
straight lines out of a total of fifty-two points. This
resulted in narrower bands for confidence limits and thus
precluded the accounting of atypical scrubber performance.
The 90% confidence intervals for the mean values, "Pt",
of the regression curve:
In Pt = A + B In q
were established utilizing the t-distribution table, 90%
confidence level, and n-2 degrees of freedom where "n"
was the number of data points. The equations are presented
in Table 6-1 and by straight lines on Figures 6-5 through
6-7. The 90% confidence intervals are also represented
by broken lines on these figures.
In lieu of a rigorous mathematical model, the equations
developed above can be used for predicting particle collec-
tion in FF/C spray scrubbers. For particles smaller than
2 ymA in diameter, the collection is mainly dependent on
particle growth and flux forces. Thus the penetration was
expressed as a function of "q" in the equations. The equa-
tions can be used to predict the amount of vapor condensa
tion required in the scrubber for the designed penetration
of fine particles. Application of the above equations is
limited to the design of FF/C spray scrubbers with the con-
figuration and operating parameters similar to the pilot
89
-------
Table 6-1. FF/C SPRAY SCRUBBER DESIGN EQUATIONS
SET *
NO.
5 . B . 1+
5.B.2
5.B.3
5.B.4
5.B.5
5.B.6
DESIGN EQUATIONS
Pt = -9. 5q
Pt =-15. 4q
Pt = -10 . 3q
Pt = -4 . 2q
Pt = -6.4q"°'2
DATA POINTS
(n)
14
6
8
9
11
* The set numbers refer to Table numbers in
Appendix 5.B.
90
-------
scrubber evaluated in this study. It is noted however
that the pilot scrubber was operated at near optimum
conditions for maximizing particle collection and thus
covers the practical design range for the horizontal
FF/C spray scrubbers.
91
-------
CHAPTER 7
ECONOMIC FEASIBILITY
Experimental results discussed in the previous sec-
tions, together with the theoretical and experimental
studies reported by previous investigators, clearly show
that fine particles can be collected with high efficiency
in FF/C scrubbers. The economic feasibility of FF/C
scrubbing is discussed in the following section. Since
there has been no published study of an industrial FF/C
scrubber, actual data on the economics of such a system
are not available. Thus, the discussion is limited to
preliminary predictions of costs based on the available
information on FF/C scrubbing.
Some general economic features of FF/C scrubbing are
discussed below. Experimental results plotted on Figures
5-6 and 5-13 indicate that it should require from 0.1 to
about 0.25 g water vapor condensed/g dry gas in a FF/C
scrubber to attain high collection efficiency for fine
particles. Such a condensation ratio generally requires
preconditioning of the scrubber inlet gas to increase
its moisture content.
Gas preconditioning could be done either by direct
introduction of spent steam if the gas is dry and has low
enthalpy, or by the evaporation of sprayed water when
enough enthalpy is available in the gas. Direct injec-
tion of steam is beneficial because it can increase the
local saturation ratio above 1.0, which is necessary
for the growth of hydrophobic particles.
Cooling water is needed to condense the desired amount
of vapor in the scrubber. In an industrial system the
water is cooled in an evaporative cooling tower using am-
bient air, and then recirculated to the FF/C scrubber.
In cooling towers of conventional design, the water
temperature range is kept below about 17°C (30°F). A
93
-------
larger water temperature range can be achieved in cooling
towers of special design but the costs will be higher
than usual, and there may be undesirable features such as
fog formation. If the water temperature rise in the
scrubber is 17°C (30°F) , about 32 g of cooling water will
be required to condense 1 g of water vapor.
COST COMPARISON
It is likely that one would have to make a choice
between using high pressure drop or FF/C conditions in
a scrubber system for fine particle collection. If equip-
ment costs for the two types of system are roughly the
same, most of the difference in operating costs will be
due to power, water, and steam requirements. In order to
compare the two approaches, operating costs have been
estimated for an FF/C system and a high energy (Venturi)
scrubber and the results are described below.
As an example case we have taken flow rate of 1,700
Kg/min of dry gas (D.G.) with molecular weight of 29.0
and an initial humidity of 0.01 g H20/gD.G. Various inlet
gas temperatures are considered and it is assumed
that the gas will reach its adiabatic saturation tem-
perature in the high energy (H.E.) scrubber and 49°C in
the FF/C scrubber outlet. A 10°C lower outlet temperature
from an FF/C scrubber could generally be attained without
great difficulty so that 49°C assumption is conservative.
The saturated gas is assumed to travel from the scrubber
to an induced draft fan and then to discharge. Thus the
fan power requirement will depend on the humidity, tem-
perature, and pressure of the scrubbed gas.
Costs were estimated for several operating modes
of an FF/C scrubber and for some combinations of inlet gas
temperature and pressure drop for an H.E. scrubber. Some
94
-------
illustrative results are shown in Figure 7-1, a plot of
hourly operating costs against condensation ratio with
parameters of scrubber type and operating conditions.
Assumptions and cost bases for Figure 7-1 are as
follows:
1. Inlet dry gas flow rate is 1,700 Kg/min, pressure
is 1.0 atm. abs., humidity is 0.01 g H20/g D.G., molecular
weight is 29.0, and temperature is as shown.
2. Cooling water could cost from 0.26
-------
0.1 0.2 0.3 0.4
CONDENSATION RATIO (q'), g/g
Figure 7-1, Operating cost comparison of
FF/C and H.E. scrubbers.
96
-------
7. Particle penetrations for H.E. scrubbers are
predicted as a function of pressure drop by means of the
method developed by Calvert (1974). The penetrations
predicted for wettable particles of 1 ymA diameter are
0.1 (i.e., 10%) at 48 cm W.C., 0.05 at 60 cm, and 0.02
at 90 cm.
Results of Comparison
In addition to Figure 7-1, the results of this com-
parison are presented in Table 7-1, showing some combina-
tions of gas conditions and operating costs. Figure 7-1
contains plots of typical values of experimental particle
penetration as a function of condensation ratio for plate
and spray type FF/C scrubbers so that the cost data can
be readily interpreted.
The three dashed lines are for the fan power costs
associated with H.E. scrubbers operating at 48, 60, and
90 cm W.C. pressure drop (as indicated on the plot) and
at actual volumetric flow rates corresponding to a given
condensation ratio. To illustrate the meaning of these
lines, gas at 600°C and humidity of 0.01 g/g would reach
an adiabatic saturation temperature of 66°C and humidity
of 0-22 g/g in a H.E. scrubber. The volumetric flow rate
due to 1,700 Kg/min of dry gas and 374 Kg/min of water
vapor would be about 2.2 x 103 m3/:min at 66°C and 1.0 atm
absolute pressure. The volumetric flow rate will be higher
at lower absolute pressures corresponding to negative
inlet fan pressures equivalent to the pressure drop across
the scrubber system.
The cost of fan power is computed from the actual
volumetric flow rate and pressure drop by the use of
the relevant assumptions and costs given above. In order
to compare the cost for H.E. scrubbing to that for FF/C
scrubbing, they have been plotted against the condensation
ratio which could have resulted if gas at the inlet
97
-------
Table 7-1.
GAS CONDITIONS AND FAN POWER COSTS
Inlet Gas
Temp.
C°C)
260
400
500
800
1,000
Humidity
(g/gD.G.)
0.01
0.01
0.01
0.01
0.01
Ad. Sat. Gas
Temp.
(°C)
49
58
66
71
75
Humidity
(g/gD.G.)
0.08
0.14
0.22
0.3
0.39
Fan Power Cost for 1,700 Kg D.G. /min, ($/hr)
Pressure Drop, cm W.C.
15cm
$2.67
--
25cm
$4.47
--
48cm
$ 9. 06
9.80
11.20
12.40
13.50
60cm
$11.50
12.40
14.00
15.60
17.00
90cm
$17.70
19.30
21.80
24.20
26.00
-------
conditions had been treated in an FF/C system. For the
600°C inlet temperature the condensation ratio would be
the difference between the adiabatic saturation humidity
and the assumed FF/C outlet humidity; that is, q'=
0.22-0.08=0.14g/g
At q'=0.14, Figure 7-1 shows the following:
Scrubber Pt @ 1 yimA Cost, $/hr
FF/C Plate 0.125 8.80
FF/C Spray 0.08 8.80
H.E. 48 cm W.C. 0.1 11.00
H.E. 60 cm 0.05 13.70
H.E.90 cm 0.02 21.50
H.E. 42 cm* 0.125 9.50
Note: *Computed for comparison at same Pt as FF/C plate
It can be seen from the above data that FF/C
scrubbing would require lower operating costs than H.E.
The cost advantage of FF/C scrubbing increases as the inlet
gas enthalpy increases and the penetration requirement
decreases. If low penetration is not required a low
pressure drop H.E. scrubber may give satisfactory per-
formance at lower cost than FF/C. The point where H.E.
and FF/C scrubbing will have the same operating cost for
the same efficiency, depending on FF/C scrubber type,
is a gas temperature of about 400°C. The condensation
ratio would be about 0.06 g/g and the predictions from
Figure 7-1 and some additional computations for H.E.
scrubbers are as follows:
99
-------
Scrubber Pt @ 1 ymA Cost, $/hr
FF/C Plate 0.21 6.30
FF/C Spray 0.12 6.30
H.E. 30 cm W.C. 0.21 6.30
H.E. 44 cm W.C. 0.12 9.00
The preformed spray scrubber of the design studied
in this program had higher efficiency than the sieve plate
column for a given value of condensation ratio as the ra-
tio decreases. In the "cold" operation mode (i.e., q'~0)
the spray gave better efficiency for a given power input
than the sieve plate and other types of H.E. scrubbers,
such as gas atomized sprays. For operation at about 2.4
&/m3 in each of three stages, as in the pilot scale spray
scrubber, the liquid pumping power would be equivalent to
about 17 cm W.C. pressure drop in terms of fan power. Thus
it is to be expected that the pre-formed spray scrubber will
be economically superior to H.E. scrubbers over the whole
range of condensation ratio.
Steam Introduction
While the performance of an FF/C scrubber at a given
condensation ratio is better if part or all of the water
vapor is introduced as steam (i.e., 1001 H20), the cost of
purchased steam will generally be prohibitively high. How-
ever, under the right circumstances the use of some steam
introduction could be economical.
The steam required for injection could be low pres-
sure, < 2 atm. gage, (< 30 psig) spent steam. It may be
obtained from the feed line to the boiler condenser in a
process plant or generated in a low pressure waste boiler
in a metallurgical operation. In this case, the steam cost
would be significantly lower and will depend on the specific
manufacturing process. In general, if such steam is avail
100
-------
able for less than $1.88/MKg, the operating costs, for a
FF/C scrubber would be lower than a venturi scrubber.
Figures 5-6 and 5-13 indicate that the "q'" require-
ment levels out around q'=0.15, so that proportionately
lesser condensation is required to obtain penetrations
lower than 5% in a FF/C scrubber. Thus, in this region,
a FF/C scrubber using some purchased steam would have lo-
wer operating costs compared to a venturi scrubber. Also,
as the most important factors in FF/C scrubbing, diffu-
siophoresis and particle growth by condensation are prac-
tically insensitive to particle size. FF/C scrubbing
would become economically more attractive as the size of
the particles to be controlled gets smaller, in the range
of 0.01 ym to 10 ym.
Industrial Application Costs
Calvert et. al. (1973) have evaluated the economic
feasibility of FF/C scrubbing systems designed for two in-
dustrial sources: A Basic Oxygen Furnace and a Kraft Re-
covery Furnace. The gas cleaning devices in these systems
were a FF/C spray scrubber for the Basic Oxygen Furnace
and a combination of a venturi evaporator-scrubber followed
by a FF/C condenser vessel with a spray scrubber for the
Kraft Recovery Furnace.
The economic feasibility of FF/C scrubbing for a gray
iron cupola is evaluated below. Due to the different de-
signs and operating practices for cupolas, it is not possi-
ble to generalize emission characteristics so a specific
cupola was selected for the case study. Emissions from this
cupola are now controlled with a high energy scrubber whose
performance was measured by A.P.T. (Calvert et al. 1974").
Information on emissions, system behavior and costs were
obtained from the cupola operators. The FF/C scrubber
system was designed for the same particle control as the
existing system and the equipment and operating costs are
compared.
101
-------
CUPOLA EMISSION CONTROL
Gray iron foundries use cupola, electric-arc, electric-
induction and reverberatory air furnaces to obtain molten
metal for production of castings. The iron melting process
is the principal source of emissions in the foundry indus-
try. Cupola furnaces are most commonly used for the melting
operations. In the foundry industry, cupola emissions are
dominant, totaling over 105,000 tons/yr as reported by
M.R.I. (1971).
The cupola emissions are presently controlled by high
energy scrubbers, fabric filters (bag-houses) and electro-
static precipitators. FF/C scrubbers are uniquely suited
for cupola emission control, due to the combination of high
stack gas temperatures (over 900°C) , fine particle sizes
(d -1.5 umA) , moderately high dust loadings (over 3 g/DNms)
Jr o
and the presence of contaminant gases.
The FF/C system described below was designed for a
2 m (80") diameter cupola. Presently the cupola emissions
are controlled with a high energy scrubber system. Details
on the performance of this system together with the cost
data have been reported by Calvert et. al. (1974) . The
cupola operation is briefly described below:
Size: 2 m (80") I.D., 9.8 m (32') high from tuyers to
afterburners and 7.6 m (25') additional height
to the top. The shell is water cooled to a
height of 6 m (20') and then refractory lined
to the top. The fuel gas flow to the two after-
burners is controlled to maintain the offtake
gas temperature between 870°C and 930°C.
Charge: Each charge consists of about 2,700 Kg of metal
(mostly cast iron), between 270 Kg to 320 Kg of
coke and fluxes as required. On an average
there are 12 charges per hour.
102
-------
The cupola emissions were reported to be as follows:
Flue gas rate = 3,400 Am3/min (119,500 ACFM) @ 900°C.
Flue gas humidity = 0.01 s , from humidity of the
ambient air.
Particulate characteristics: 3.5 g/DNm3 (8 gr/DSCF), log
normally distributed with mass mean diameter,
d =1.15 ymA and a =1.7.
PS g
The present high energy scrubber system has an overall par-
ticulate removal efficiency of 97% at the scrubber pressure
drop of 275 cm W.C.
The FF/C Scrubber System
The FF/C scrubber system was designed to yield 97%
particulate collection efficiency, identical to the per-
formance of the high energy scrubber. A spray configura-
tion was selected for the FF/C scrubber due to the low
pressure drop requirement. Based on the FF/C spray scrub-
ber tested in this study, q'=0.18 is considered sufficient
to achieve the desired particulate removal, with the over-
all liquid sprayed to gas flowrate ratio of 4.5 £/m3(34
gal/MCF) .
A process diagram of the FF/C scrubber system is
shown in Figure 7-2. As described earlier, stack gas from
cupola offtake is maintained at about 900°C by adjusting
the afterburners. Immediately downstream of the refrac-
tory-lined offtake, 150 £pm of water is sprayed in as fine
mist, cooling the gas to 427°C. This serves the purpose of
reducing heat losses from the 90 m long duct to the scrub-
ber system, as well as permitting the use of smaller dia-
meter mild steel duct. Gas temperature at the quencher in-
let is determined to be 280°C after accounting for the heat
losses .
103
-------
WATER '
SPRAYS 1
1 |2
FROM
CUPOLA
•t
ENTHALPY
LOSS FROM DUCT
CT
>
'8
pi
w
X
u
;s
w
ex
>
'9
^
s~
r
TO I
.
., 4
CAUS
FOR
CONT
.D. PAN,
I5
tf
w
pa
m
u 3
\Pi
n. u
PU CO
t ^
TIC
-L n .. .-
pn
ROL ,,
T T HI IDD
TREATMEf
STACK
6
J
^
4T
->—
AIR
COOLING
TOWER
t
AIR
BLOW
A>T
MAKE-UP
WATER
) SLUDGE
DRAIN
CO
o
1— I
ex
i — i
STREAM
NO.
1
2
3
4
5
6
7
8
9
TEMP
°C
900
427
280
69
49
27
46
64
69
VOLUME
FLOWRATE
Am3/min
or £/min
3,400
2,480
1,850
1,300
970
5,870
6,040
400
300
GAS
HUMIDITY
2 vapor
g D.G.
0.01
0.16
0.16
0.26
0.08
PRESS
cm W.C.
-2
-7
-15
-20
35
LOADING
g/DNm3
3.5
3.5
3.5
3.5
0.105
FIGURE 7-2 Process diagram for cupola gas cleaning
104
-------
The gas is then further cooled and humidified by re-
circulating water sprays in the quencher. As the size
distribution of particles in the stack gas is fine, with
over 99% by mass of particles smaller than 5 ymA, water
sprays in the quencher are not expected to remove any sig-
nificant amount of particles. The desired particulate re-
moval is achieved in the FF/C spray scrubber. The scrubbed
gas is cooled down to 49 °C in the scrubber, condensing out
0.18 g vapor/g d.gas on the liquor sprays. The overall pres
sure drop across the system is determined to be 35 cm W.C.
The liquor system includes a cooling tower and provi-
sions for clarification and pH control of the recirculated
liquid. The uniformly packed cooling tower uses ambient
air for evaporative cooling of the liquid sprayed in the
scrubber. Clarification of the recirculated liquid is
attained by settling out the suspended solids in tanks,
with a total retention time of about 45 minutes. The sett-
ling process is enhanced by the addition of coagulants.
Caustic soda solution is added in the tanks to maintain the
pH between 6 and 7. A constant blowdown from the tanks con-
trols the concentration of dissolved solids in the liquid
stream. A water wash is provided in the cooling tower to
periodically clean out scale formed on the packing surface.
City water is added into the cooling tower to make up for
the blowdown, entrainment, evaporative and other losses from
the recirculated liquid system.
Cost Comparison
Equipment for the system shown schematically in Figure
7-2 was selected and sized for the purpose of cost estima-
tion. Capital cost information was obtained from the fol-
lowing sources: A.P.T. Scrubber Handbook (1972), Cost
Engineering iri the Process Industries (1960) , Modern Cost
Engineering Techniques (1970) , and Chemical Engineers'
Handbook, Fifth ed., (1973). The method was based on
105
-------
calculating the F.O.B. equipment cost and then multiplying
by various factors for the costs of internals, piping, in-
strumentation, etc. The capital costs were then adjusted
to a common time base, 1974, using the Marshall § Stevens
Equipment Cost Index.
Installation costs for the scrubber system, to include
modifications in existing process, site preparation, foun-
dation, start-up, etc. were not determined, as they are ex-
pected to be comparable to the costs for the high energy
scrubber system. Similarly, the operating costs for labor,
liquid treatment, and solid disposal, together with the
maintenance costs for labor and materials, are expected to
be comparable for the two scrubber systems. Thus, the only
operating costs compared are the electrical power require-
ments and annualized capital charged and depreciation taken
as 20% of the capital costs. Table 7-2 shows the cost com-
parisons .
The FF/C scrubber system requires additional equipment
such as the quencher and the cooling tower. Due to the
higher flow requirements of recirculated liquid, the liquid
system costs are also higher for the FF/C system compared
to the high energy (H.E.) scrubber. However, these costs
are more than offset by the higher cost for fans for the
H.E. scrubber system. Three fans are required for the H.E.
system, adding up to 1,080 KW (1,450 HP) as compared to one
127 KW (170 HP) fan required for the FF/C system. Note that
costs for piping and ducting for both the systems are ex-
pected to be the same, although they are significantly dif-
ferent. The FF/C system has a higher piping requirement
and requires the 90 m duct to be lightly insulated. These
costs are expected to approximately offset the cost of addi
tional ducting used in the H.E. system to jacket the 90 m
duct.
106
-------
A comparison of costs for the two systems indicates
that the total equipment costs are approximately the same.
The H.E. system, however, costs about $63,500 more per
year to operate, as the annual cost for electrical power
is more than 2.6 times that for the FF/C system. Electri-
cal power cost of $0.03/KW-HR was used for the above cal-
culations. Power costs have increased steadily in recent
years and there are no immediate indications for a change
in this trend. As the cost of electrical power increases
and energy conservation becomes more important, the FF/C
scrubbing system will prove to be more attractive, compared
to a high energy scrubbing system.
107
-------
Table 7-2. COST COMPARISON OF CUPOLA EMISSION CONTROL SYSTEMS
COST ITEMS
A. Capital Costs
1. F.O.B. quencher with
internals, flange to flange
2. F.O.B. scrubber with
internals, flange to flange
including entrainment
separator
3. F.O.B. cooling tower
4. Fans, motors and
motor starter
5. Liquid treatment and
solid handling equipment,
including pumps .
6. Piping and ducting (2)
7. Instrumentation and
electrical material (3)
TOTAL EQUIPMENT COST
B. Annual Operating Costs
1. Electrical power for
fans and pumps.
2. Annualized capital
charges and depreciation
(20% of capital costs)
TOTAL
High Energy
Scrubber
System ($) (1)
-- (4)
18,600
156,370
50,030
102 ,570
22 ,900
350,470
102",560
70,100
$172 ,660
FF/C Scrubber
System
($)
12 ,140
32,460
34,950
35,000
80,000
102,570
15,640
312,760
38,900
62,550
$ 101,450
Notes :
1
Actual costs obtained from the user, converted to 1974
2. Due to equivalent complexity, the costs were assumed
same for both systems.
3. Taken as 5% of equipment costs for the FF/C system.
4. Quench spray costs for both the systems are included
in the ducting costs.
108
-------
CHAPTER 8
FUTURE RESEARCH RECOMMENDATIONS
The preliminary objective of examining the technical
and economical feasibilities of FF/C scrubbing for the
collection of fine particles , through experimental evalu-
ation of two FF/C scrubbers, has been achieved in this study.
It has been clearly shown that FF/C scrubbing is capable of
high efficiency fine particulate removal. Areas of economic
application of FF/C scrubbing at industrial sources have
been identified. These include some of the major stationary
air pollution sources in the U.S.A. as listed in the Midwest
Research Institute report (1971). Mathematical design models
have been developed also for the two FF/C scrubbers studied.
To continue this development work so that the advantages of
FF/C scrubbing could be derived for industrial application,
we recommend future research work in the following areas:
1. Demonstration of the feasibility of FF/C scrub-
bing on selected industrial sources.
2. Theoretical and experimental evaluation of other
low energy scrubber configurations to determine
the best configuration applicable to FF/C scrub-
bing systems.
3. Development of evaporative cooling devices suited
for the cooling of scrubber liquid containing
suspended and dissolved solids.
4. Theoretical and experimental determination of the
specific details of heat and mass transfer in gas-
liquid systems, the nucleation of condensation
and other matters which critically affect the
applicability of FF/C scrubber design equations.
109
-------
DEMONSTRATION OF FF/C SCRUBBING
A detailed test program to demonstrate FF/C scrubbers
at pilot scale for the control of fine particulate emissions
from three industrial sources is described below. The fol
lowing criteria were used for selecting the industrial sources
I. The national importance of the industrial parti
culate emission sources as major pollutants.
II. Applicability of FF/C scrubbing in terms of its
technical and economic feasibility.
III. Sources which are either difficult or expensive
to control with presently available particulate
control devices.
Three sources were selected which would enable demon-
stration of the operational reliability of all the compo-
nents of an FF/C scrubbing system. These sources are
described below:
Secondary Nonferrous Metals Recovery Furnace
The secondary nonferrous smelting and refining indus-
try generally uses gas-fired furnaces to recover copper,
aluminum, lead and zinc from scrap and dross. The nature
of furnace operations is such that emissions vary widely
during the cycle from charging the scrap to pouring a melt.
Peak emission surges occur in nearly all the furnace opera-
tions. The principal emissions from these furnaces are par-
ticulates in the form of smoke, dust, and metallic fumes.
However, during copper wire reclamation, considerable amounts
of acidic and corrosive gases comprised of fluorine and chlo-
rine compounds are also present, depending on the composition
of the wire insulation. With emission rates of about 127,000
ton/year, this industry was ranked among the top fifteen
national source pollutants in a survey by Midwest Research
Institute (1971) .
110
-------
Due to the cyclic nature of the emission, high flue
gas temperatures O500°C to 900°C), presence of corrosive
gases and high efficiencies required for fine particulates,
the recovery furnace emissions have been difficult and ex-
pensive to control. Generally, afterburners are used fol-
lowing the furnace to burn out hydrocarbons in the flue gas.
High energy scrubbers, electrostatic precipitators and
fabric filters have then been applied to remove the particu-
lates. None of these have proven reliable for maintenance
free operation. No control device is presently available to
control emissions from copper -wire recovering operations,
although over 300,000 ton of insulated wire is recycled an-
nually resulting in emissions exceeding 41,000 ton/year.
We recommend that FF/C scrubbing should be demonstra-
ted on a recovery furnace, especially one operated for copper
wire reclamation. A pilot scale system with a capacity of
140 to 280m3/min is recommended. A small furnace with a pro-
cess load of about 450 Kg/hr; with 20-minute cycles, would
be ideally suited for the demonstration. The total flue gas
emission of such a furnace would be in the range of the pilot
scale FF/C scrubber capacity so that the effect of the cyclic
nature of emission could be best evaluated. This would per-
mit also a study of the FF/C system performance for the simul
taneous removal of fine particulates and corrosive gases,
using alkaline scrubber liquor.
Glass Furnace
The glass manufacturing industry , and especially the con-
tainer glass industry, is faced with a nation-wide need for
the application of particulate control systems on the glass
furnaces. Glass furnace emissions have been difficult and
expensive to control due to a high fraction of fine particulates,
111
-------
high stack gas temperatures and the presence of gaseous
contaminants. However, these emission properties are
favorably suited for economic application of FF/C scrub-
bing.
A typical furnace produces from 80 to 140 metric
tons of glass per day on a 24 hrs/day schedule. Typical
flue gas properties for a furnace producing amber glass
are as follows:
Gas Conditions :
Flowrate: 300 m3/min @ 20°C
Temperature: 450 °C
Particulates :
Loading: 0.2 g/m5 @ 20°C
Emissions: 4 Kg/hr.
Composition: ^90% Na2S04
1 CaS0
4
trace amounts of other constituents
The particles are '^1.0 ymA, with geometric standard
deviation less than 3 .
Gaseous contaminants:
SO : 80 ppm
NO : 1,500 ppm
.X.
In addition to the removal of gaseous contaminants,
over 80% removal of particulates is required and the opacity
limited to less than 20%. An FF/C scrubber has the additional
advantage of particle growth, as ^90% particulates are soluble
in water and would grow at a saturation ratio of less than
one. This would be one of the major aspects of the demon-
stration. Again, a pilot scale system with a capacity of 140
to 280m /min is recommended.
112
-------
Gray Iron Foundry Cupola
Gray iron foundries use several types of furnaces to
melt and recover iron from scrap for the production of
castings. Cupola furnaces are most prominently used for
the melting operations. The iron foundry industry was rank-
ed among the top 15 national stationary-source pollutants
in the Midwest Research Institute (1971) survey. In the
foundry industry, cupola particulate emissions are dominant,
totaling over 105,000 ton/year. Physical processes, chemi
cal reactions, and the quality of scrap affect the emissions
of dust and fumes from cupola, thus no typical flue gas con-
dition can be defined. For example, emissions from a 86 cm
(34") cold blast cupola with a production rate of 45 Kg
(100 Ib) molten iron per minute are listed below:
Flue gas rate = 520 A m3/min (18,350 ACFM) @ 980°C
Flue gas rate = 115 N m3/min (4,000 SCFM)
NOTE: The flue gas rate and temperature are maintained
constant by adjusting gas flowrate to an after-
burner located above the charge door.
Average flue gas composition, before afterburn, vol I:
C02: 121
CO : 14.91
N : 73.1%
3
Particulate loading: 1.0 g/DN m3 (2.3 gr/DSCF)
The particulate size distribution data reported in the
literature for cupola emissions were found to vary consid-
erably from source to source. Due to the carbon particles
present in the emission, the particles are considered to
be non-wettable .
Cupola emissions have been difficult and expensive to
control due to the high emission rates of fine particulates ,
high gas temperatures and significant changes in the emission
characteristics during the operation cycle. At present,
113
-------
electrostatic precipitators, high energy scrubbers and
fabric filters (bag houses) are used to control these emis-
sions. The high gas temperatures and fine particulate
loadings prompt the economic use of FF/C scrubbers. Again,
a 140 to 280m3/min pilot scale FF/C system is recommended.
A detailed demonstration test program, including the
cost and time estimates, is described below. Although the
details of FF/C scrubbing system design will be different
for each source, the overall process design, illustrated
in Figure 8-1, will be the same. Since the test matrices
for the demonstrations would also be of comparable complex-
ities, we expect that the cost and period of performance for
each demonstration will be the same. Any variations in
these estimates can be easily accommodated when more details
on the installation and operation of the industrial source
in question are available.
In outline, the objectives consist of the following
tasks:
1. Select a company which operates a suitable plant
involving one of the above operations for the
demonstration of FF/C scrubbing and obtain re-
quired clearances from the local air pollution
control agency.
2. Design the demonstration scrubber system on the
basis of:
A. Pertinent data concerning the source obtained
through source testing.
B. Evaluations of alternative FF/C scrubber
system designs.
3. Prepare a detailed test plan describing:
A. The measurement techniques to be used.
B. Error analysis of the measurement techniques.
C. The proposed test matrix.
D. The data handling procedures.
114
-------
City
Water-
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t
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M*
r
c
^
i_,
idense
o
J
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/
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Water
>•
u
*\
ft
1
fcr
fll
" 3
o
i
1
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K
10 stac
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£ fn
•H 0)
•-H £
O O
O E— '
4 .
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— J
To drain or
Liquid Treatment
Air
Figure 8-1 - Typical process design of a FF/C scrubber system
-------
4. Fabricate, install and start up the FF/C scrubber
system as developed in 2 above.
5. Conduct the test program as developed in 3 above.
6. Remove the pilot FF/C scrubbing system and restore
the site to its normal condition less fair wear and
tear.
7. Conduct an engineering and cost analysis of the
FF/C scrubber system to evaluate:
A. Scrubber operating and capital cost.
B. Scrubber operation and maintenance problems.
C. Scrubber reliability.
D. Scrubber performance.
8. Based on the above analysis and the additional
information available on scrubber design, design
and estimate the cost of an optimum FF/C scrubber
system for the industrial source.
9. Define the areas of FF/C scrubbing in which addi
tional information is needed to improve the via
bility of the FF/C scrubber application.
10. Survey emission conditions for similar sources to
determine a group of industrial operations where
the optimum FF/C scrubbing system developed above
is economically applicable with minor modifications
11. Recommend a test program to demonstrate a full
scale FF/C scrubbing system on a similar industrial
source.
For the purpose of estimating the cost and time require
ments, the following task breakdown was used:
Task 1 - Select company
a. Survey the industry and contact companies
b. Preliminary screening
c. Contact screened candidates to obtain additional
information and perform sampling, where needed.
116
-------
d. Refine calculations of conceptual designs
based on "c" above.
e. Consult the contracting agency.
f. Select the company for the demonstration.
g. Consult the local air pollution control agency.
h. Finalize the arrangements.
Task 2 - Design the demonstration pilot plant
a. Obtain more data on the source
1. Sample the source
2. Conduct small-scale (10-20 CFM) tests on
the source to test out concepts for scrubbing,
liquor cooling, monitoring, etc.
b. Evaluate alternatives by means of:
1. Preliminary designs
2. Laboratory bench scale tests
3. Laboratory pilot scale tests
4. Additional small-scale tests at source
5. Finalize alternative designs
6. Compare alternative designs
7. Consult contracting agency
8. Consult company
9. Clear with local air pollution control agency
10. Make detailed design and specifications of
demonstration pilot plant.
Task 3 - Prepare detailed test plan
a. Develop plan
b. Error analysis
c. Define procedures
d. Finalize measurement and monitoring procedures
Task 4 - Fabricate, install, start up
a. Select vendors and place orders
b. Arrange for site modifications
c. Follow up vendors and assemble components
d. Install pilot plant
e. Start up pilot plant
117
-------
Task 5 Conduct test
a. At near-optimum conditions
b. At excursions from optimum
c. Configuration variations
Task 6 - Remove pilot system and restore site
Task 7 - Engineering analysis
a. Operating and capital costs
b. Operating and maintenance problems
c. Reliability
d. Performance
1. Scrubber
2. Liquor system and other auxiliaries
Task 8 - Optimum FF/C system
a. For this plant condition
b. For other capacities.
Task 9 - Evaluate FF/C scrubbing system performance to
define areas for additional investigation
Task 10- Survey emissions from other sources to deter-
mine a group of operations with similar
emission problems
Task 11- Recommend full scale test program
A performance schedule for this program is described
in Table 8-1. The overall period of performance is 18
months for the demonstration program. It is noted that
additional demonstration programs performed on the other
industrial sources would require 14 months, if performed
by the same contractor.
A detailed cost breakdown for the demonstration program
is described in Table 8-2. It is noted that the costs were
based on 1974 prices and for the FF/C scrubbing system only.
If there are special construction and installation problems
at the industrial source, the costs should be adjusted ac-
cordingly. It is expected that additional demonstration
118
-------
TABLE 8-1: ESTIMATED SCHEDULE OF PERFORMANCE
Task
No.
la
b
c
d
e
£
g
h
2a 1
2
b 1
?
3
4
5
6
7
8
9
10
M
X
QJl-f-Vl #1
/
/
y
2
^\
\
\
7>
'•-*
\
/
/
/
/
/'
/
vv
/
/
4
/
/
/
/
/
/
^ ^/
X
/
5
v'
\
X
X
X
6
/
y
-------
TABLE 8-1: (Cont.)
INJ
o
Task
No.
2 b 3
4
3 a
b
c
d
4 a
b
c
d
e
5 a
b
c
7 a
b
c
d
Month #7
/
/
/'
/
/
/'
-
X
8
/
x
X
9
\
X
/
10
X
X
x
11
y
;<
12
/
/
/
X
X
-------
TABLE 8-1: (Cont.)
Task
No.
5 a
b
c
6
7 a
b
c
d
8
9
10
11
Month #13
/
/
><
14
/
X
15
/
X
16
^
>"
/ \
X
X
17
/
y
18
/
/
\
\
\
\
-------
programs at the other industrial sources would cost about
80% overall, if performed by the same organization.
Table 8 -2
DETAILED COST BREAKDOWN
Task
No.
1
2
3
4
5
6
7
8
9
10
11
TOTAL
Direct
Labor
($)
16,000
32,000
15,000
19,000
19,500
6,500
4,500
4,500
4,000
5,000
4,000
130,000
Other
Direct Costs
($)
4,000
18,500
5,000
40,000
4,500
2,500
74,500
The above estimates were made on the assumption that
the performing organization is eminently qualified in the
research and development field, with special knowledge,
background and interest in the specific field of particulate
removal by FF/C scrubbing.
122
-------
EVALUATION OF OTHER SCRUBBER CONFIGURATIONS
During the performance of this contract, multiple sieve
plate and horizontal spray scrubbers were evaluated, when
operated in the FF/C scrubbing mode. Several other con-
figurations of conventional and novel designs are presently
available for low pressure drop scrubbing, such as the
mobile bed scrubber and the packed bed scrubber with con-
ventional and new packings. We recommend that these con-
figurations be evaluated to determine their applicability
to FF/C scrubbing. The following approach is recommended:
1. Survey scrubber manufacturers and users to assimi-
late design and operating information on low energy
scrubbers with high gas residence times . The scrub-
bers should be multi-stage or continuous contact
type.
2. Screen and select promising scrubber configurations
based on theoretical evaluation of the scrubber per-
formance when operated in the FF/C scrubbing mode,
for the collection of fine particles.
3. Conduct a limited bench scale study to obtain in-
formation in the critical areas of scrubber opera-
tion, so that the FF/C scrubber model could be
theoretically derived.
4. Determine the technical and economic feasibilities
and the special area of application for these scrub-
bers by using the models developed above. The
feasibilities should be determined by a comparative
evaluation of all the FF/C scrubbers considered.
5. Select promising scrubber mechanisms and conduct a
detailed experimental study as follows:
a. Laboratory pilot scale study with scrubber capa-
city between 14 and 28 m3/min.
123
-------
b. Pilot scale demonstration on selected industrial
sources with scrubber capacity between 140 to
280 m3/min.
c. Full scale demonstration on a selected industrial
source.
It is noted that performance of each of the above tasks
would depend on the results of the preceding tasks. The
program objective is to determine FF/C scrubber configura-
tions best suited for specific industrial operations or a
group of operations with common particulate control problems.
DEVELOPMENT OF LIQUOR COOLING SYSTEM
Due to the large requirement of cold scrubber liquor
and the complications introduced by dissolved and suspended
solids, the liquor cooling procedure has a significant
effect on the economics of a FF/C scrubber system. The
scope of the proposed work is to evaluate the liquor cool
ing system alternatives, select the most promising system
and make an experimental study to determine its perfor-
mance, economics and applicability.
The following approach is recommended:
1. Determine all factors affecting the liquor cooling
system for a FF/C scrubber. These include such
things as economic considerations, effect on
scrubber performance and the concentrations of
dissolved and suspended impurities in the liquor.
2. Evaluate cooling system alternatives and select
the most promising for experimental study.
3. Conduct an experimental study on a suitable scale
to determine its performance, economics, appli-
cability and scale-up considerations.
124
-------
APPENDIX 5.A
MULTIPLE SIEVE PLATE FF/C SCRUBBER
OPERATING CONDITIONS AND PERFORMANCE
125
-------
Table 5.A.I
"l.?tc configuration
FIVE PLATE FF/C SCRUBBER; OPERATING CONDITIONS AND PERFORMANCE
Dust used
Cold water in
Five identical plates with 3.2 mm round perforations
Free area 9%; Plate active area = 9.29x10" m
Pure black iron oxide, 16 mesh, dry dispersed
troduced on top plate, flow rate 0.64 liters/sec.
\un
1 o .
i
3
A
5
r
7
3
9
Flow
nM™3\
5 . 17
5 . 3
5 . 3
5 .14
4.73
4 .85
5 .06
3 . 08
2 . 83
Temp .
<"C)
20
25
23
42
43
55
60
68 .2
71.2
ditions
Moi s ture
(
30 . J
31 . 33
30.6
29.6
29 . 5
126
-------
Table 5.A.3. FOUR PLATE FF/C SCRUBBER, OPERATING CONDITIONS §
PERFORMANCE
Plate configuration: Four 'identical plates with 3.2 mm round
perforations. Free area = 9%; Plate active
area = 9.29xlO~2 m2
Dust used: Titanium dioxide, -16 mesh
Cold water introduced on the top plate, flow rate = 0.64 liters/sec
Run
No.
19
20
21
22
23
Gas Inlet Conditions
Flow
(dsm3\
7 .90
8.13
8.43
8.51
8.31
Temp .
CO
56.0
63.0
60.5
61 .0
60.5
Mo i s ture
t* Vol.)
16 .2
21.4
20.8
21.0
20 .8
q1
xlO
0 .90
1.23
1.25
1.35
1.32
CO
In
27.5
31.2
27.8
24.5
25.0
Out
55.4
54.7
53.0
60.0
60.0
Scrubber
Drop
(cm W.C. )
29.8
37.2
33.9
34.9
35.1
Run
No .
19
20
21
22
23
Load x 103
(g/dsm3)
244
308
456
271
359
58.8
65.1
59.7
47.6
53.8
d
P9
0.72
0.97
0.89
0.88
F.
0 .60
0. 58
0.63
0 .87
Iter R
Og
In
2 .9
3.0
3.0
2 . 7
un
2 .0
1.7
1.8
2 .6
ni
xlO-e
4 .5
3.0
5 .9
1 .1
Ft
(»)
24.1
21.1
13 .1
17.6
15 .0
Table 5.A.3.
FOUR PLATES FF/C SCRUBBER: OPERATING CONDITIONS
PERFORMANCE (continued)
Plate configuration: Four identical plates with 3.2 mm
round perforations. Free are = 9% •
plate active area = 9.29 x 10~amz
Dust used: Titanium dioxide, —16 mesh
Cold water introduced on the top plate;
flowrate = 0.64 liters/sec
Run
No.
24
25
26
27
28
29
30
31
32
Gas Inlet Conditions
Flow
,-dsm3
^min
8.23
8.28
8.37
8.14
8.25
8.33
8.35
8.28
8.30
Temp.
(°C)
22.8
28.3
34.5
44.3
45.3
49.3
49.8
59
59.8
Moisture
(t vol.)
1.7
1.5
1.6
9.2
9.8
9.1
12.2
19
19.7
q'
xlO
0.40
0.53
0.55
0.63
1.11
1.17
Liquid Temp.
(°C)
In
15.2
18.5
20.3
22.5
14.8
21
25.3
26.2
26
Out
18
26.5
23.5
43.5
39.2
49
49
58.8
59.5
Scrubber
Press
Drop
(cm W.C.)
28.3
28.4
29.5
30.7
32.1
32.5
33.5
34.8
33.8
Run
No
24
25
26
27
28
29
30
31
32
Particulate
In
203
166
267
181
74.2
190
169
313
296
Out
88.9
65.6
114
46.2
19
37.4
38.8
70.9
52.2
d™
In Out
filter ru
1.15
fil
0.91
0.98
0.66
0.89
ter ru
0.77
0 .72
0.66
o
In
i
2.1
n
2.6
2.4
2.7
filter run
filter run
0.91
0.70
3.2
Out
2
1.9
1.9
2.4
1.9
n .
x 10-'
0. 5
4.5
1.4
23.5
103.3
PT
W
43.8
39.6
42 8
25.6
25.6
19.7
22.9
22.6
17.7
-------
Table 5.A.3. FOUR PLATES FF/C SCRUBBER; OPERATING CONDITIONS §
PERFORMANCE (continued)
tx)
OO
Run
No.
33
34
35
36
37
38
39
40
41
42
43
44
45
Gas Inlet Conditions
Flow
,dsm3.
lmin '
7.90
8.53
8.43
8. 70
6.14
6. 11
6. 76
7.02
6.53
S. 78
4.66
5. 25
5.51
Temp .
C°C)
60.8
60.3
61
69 .8
73.8
70.8
70.5
74
76
76
78
77.8
77
Mo is ture
(«. vol.)
20.2
19.82
20 .78
31.1
36.22
31.9
32.4
36.55
38.5
39.6
42.5
42.9
42 .2
q'
xlO
1.22
1 . 23
1.26
2.24
2.31
2.36
2.60
2.99
3.01
3.20
3.30
3.48
3.72
Liquid Temp.
C°C)
In
23
23.4
22 .5
21.5
28.9
22.6
19
25.5
22.3
25
23. 8
27
22.5
Out
60.5
51
52
68
73
70.5
70.5
74
78
77.5
77
79
76
Scrubber
Press
Drop
(cm W.C.)
35.7
35 .3
35 .7
36.5
37.2
37.1
34
37.1
35.1
38.9
38.2
38.4
34.7
Run
No.
33
34
35
36
37
38
39
40
41
42
43
44
45
Particulate
Load x 10 ' (g/dsm*)
In
198
236. 5
156.4
296
346.4
337
158
339. 7
81.4
330
360
548
290
Out
32.7
34.9
35.1
25
54.5
31.7
16.6
40.1
3.9
44. 5
56
81 .7
31.9
d
Pg
In
fil
Out
ter ru
a
g
In
n
filter run
1.21
1.11
1.1
1.05
0.62
0.81
0.62
0.83
filter ru
filter ru
1 .25
0. 77
0.85
0.68
0.55
0.76
2
3
2.7
2.8
l
i
3.4
3.6
3.5
filter run
filter run
l
Out
1.7
2
1.9
1.9
2.1
1.4
2.8
n.
x ID'7
0.31
1.9
7 .3
9.5
29 .5
648.3
720
PT
W
16.5
14.8
22.4
8.5
15 .7
9.4
10.5
11.8
4.8
13.5
15.6
14.9
11
Table 5.A.4 FOUR PLATE FF/C SCRUBBER; OPERATING CONDITIONS
AND PERFORMANCE
Plate configuration: Four identical plates with 3.2 mm
round perforations. Free area = 9°.;
plate active area = 9.29 x 10"zm2
Dust used; Titanium dioxide, —16 mesh, dry dispersed.
Cold water introduced on the top plate;
flowrate = 0.38 liters/sec
Run
No.
46
47
48
49
50
51
52
53
54
Gas Inlet Conditions
" Flow
/•DN"i'
^min
9.56
11.15
8.72
10.19
9 .64
9.72
9.68
9.58
10.06
Temp .
(°C)
33.0
27.0
36.0
21.5
45 .8
44 .8
45.0
46. 5
55.0
Mois ture
(% vol.)
2.52
1.6
1 .72
1 . 7
9.9
9 .7
9.4
10 .4
15.7
q '
xlO
—
—
—
0 .43
0.43
0.40
0 .52
0 .68
Liquid Temp.
( °C)
In
30.0
16.0
23.0
19.5
19 .0
22.5
21.2
16.0
23.0
Out
22.0
19 .3
22.0
20.0
46.8
43.8
45.5
43.0
54 .5
Scrubber
Press
Drop
(cm W.C.)
34.2
38.0
34.0
35 .6
31.8
31.4
31.8
31.9
37 .6
Run
No .
46
47
48
49
50
51
52
53
54
Particulate
Load x 103 (g/DNm3)
In
151.6
271
89 .4
264
224
246
209
140
217
Out
50.7
96.3
30.57
78.7
51.8
63.8
62.2
30.8
43.8
dp.
in
fil
fil
1.1
fil
fil
fil
0.91
1.15
fil
Out
o
g
In
ter run
ter run
0.95 |1.95
ter run
ter run
ter run
0.82
0.85
ter r
2.0
2.9
un
Out
—
1.7
—
—
—
1.9
2.3
~
ni
x 10-'
—
2.42
—
—
—
11.8
44. 5
"
Ft
W
33.4
35.5
34.2
29 .4
23 .2
26.0
29.7
22.0
20.2
-------
Table 5.A.4 FOUR PLATE FF/C SCRUBBER; OPERATING CONDITIONS
AND PERFORMANCE (continued)
Table 5.A.4
Run
No.
55
56
57
58
59
60
61
62
63
64
65
66
67
Gas Inlet Conditions
Flow
9.84
10.08
12.7
8.56
7.38
8.07
8.45
7.07
6.98
6.51
6.96
6.31
4.9
Temp.
(°C)
56.8
54.5
55.0
65.0
67.5
65.3
64.5
69.5
70.3
71.5
72.5
71.0
73.5
Moisture
(% vol.)
16.6
15.5
15.6
23.7
25.1
25.0
24.9
29.3
31.1
33.0
33.7
32.3
33.8 -
q'
xlO
0.82
0.71
0.74
0.99
1.16
1.24
1.34
1.05
1.2
1.4
1.8
1.15
1.3
Liquid Temp .
f°C)
V. "-1 J
In
20.5
23.3
56.0
20.7
22.0
22.0
16.5
24.0
23.0
22.3
20.0
24.5
22.0
Out
58.0
54.5
24.0
65.5
58.0
65.5
61.0
73.0
70.2
75.4
73.5
71.5
73.0
Scrubber
Press
Drop
(cm W.C.O
37.2
36.5
37.1
37.1
35.2
34.5
37.1
37.0
39.0
37.2
37.6
35.3
38.6
FOUR PLATE FF/C SCRUBBER; OPERATING CONDITIONS
AND PERFORMANCE (continued)
Run
No.
68
69
70
71
72
73
74
75
Gas Inlet Conditions
Flow
, DNn 3 -,
'•rain '
7.17
7.06
7.27
5.07
5.38
5.65
4.96
5.51
Temp .
(°C)
71.8
70.8
71.5
77.0
77.3
76.2
80.2
76.8
Moisture
(% vol.)
32.8
31.7
33.2
39.4
39.9
37.7
40.7
40.5
1'
xlO
1.3
1.4
2.0
1.50
1.70
1.60
1.80
2.15
Liquid Temp.
in
22.5
17.5
17.5
23.0
26.0
23.3
23.3
19.8
Out
70.0
72.0
69.5
80.6
78.3
75.0
83 8
78.0
Scrubber
Press
(cm W.C.)
38 6
36 8
37 5
38 7
38 6
38 5
36.8
to
Run
No.
55
56
57
58
59
60
61
62
63
64
65
66
67
Particulate
Load x 103((g/DNm3)
In
156
203
122
174
304
166
204
271
358
282
267
215
192
Out
40.3
49.3
29.9
30.2
54.9
33.7
38.5
49.6
61.0
53.0
42.8
39.7
31.4
-------
Table 5.A.5. FIVE PLATE FF/C SCRUBBER; OPERATING
CONDITIONS AND PERFORMANCE
Plate configuration: Five identical plates with 3.2 mm round
perforations. Free area = 9°,; Plate
active area = 9.29 x 10"2m2
Dust used: Titanium dioxide, -16 mesh, dry dispersed
Cold water introduced on the top plate, flowrate = 0.38 liters/sec
Note: Scrubber inlet and outlet sampled simultaneously with
University of Washington Mark III cascade impactors.
No.
76
77
78
Gas Inlet Conditions
Flow
,DNm31
(min '
8.80
7.38
8.66
Temp
C°c)
30
18.5
18.5
Mo i s ture
(°. vol.)
1.9
1.13
1.8
q'
xlO2
-
-
Liquid Temp.
(°C)
In
26
17
21
Out
20
18
22
Scrubber
Press
Drop
(cm W.C.)
35.4
33.4
20 .8
Run
No.
76
77
78
Particulate
Load x 103(g/DNm3)
In
68
82.5
138
Out
26
26.6
28.9
d
Pg
In
1 .35
1.30
1.35
Out
1.12
1.01
0.86
a
g
In
1.7
1 .7
1.9
Out
1.4
1.8
1.8
n .
i
xlO'6
0.5
0.7
1 .7
Ft
O)
38.2
32.25
20.8
Table S.A.5 FIVE PLATE FF/C SCRUBBER; OPERATING CONDITIONS
AND PERFORMANCE (continued)
Run
No.
79
80
81
82
83
84
85
Gas Inlet Conditions
Flow
,DNm3,
'-"mTn" >
6.61
7.72
7 .91
7.72
7.68
6.78
7.07
Temp
(°C)
47.8
47.0
46.0
46 .0
55
57
56
Moisture
( % Vo 1 . )
9.87
9.60
9 .66
9.22
15.35
15.63
15.62
xlO2
4.1
4.6
4.7
5.3
8.3
8.7
8.9
Liqu id Temp .
(°C)
In
14
18
21
15
22
20
23
Out
46.5
47
47
43
56
57
53
Scrubber
Press
Drop
(cm W.C.)
33.3
47.2
43.2
42.5
48.3
40.4
45.7
Run
No.
79
80
81
82
83
84
85
Particulate
Load x 103 (g/DNm3)
In
65.4
76.0
165.5
125.7
200
186
233
Out
6.5
11.5
29.0
20.7
33.8
34.4
32.1
dpg
In
1.49
1.51
1.32
1.4
1.3
1.19
1.1
Out
0.67
0.96
0 .98
0.84
0.85
0.98
0.92
a
g
In
2.0
1.8
1.9
2.0
1.6
2.1
2.1
Out
1.7
1.8
1.7
1.8
1 .6
1.8
1. 7
n .
i
xlO-6
0.7
0.5
1.4
1.2
1.6
16^.7
8.0
Pt
CO
10
15.16
17.5
16.76
16.9
16.3
13.7
-------
Table 5.A.5
FIVE PLATE FF/C SCRUBBER; OPERATING CONDITIONS
AND PERFORMANCE (continued)
Run
No.
86
87
88
89
90
91
Gas Inlet Conditions
Flow
( DNn3-,
Lmin '
4.92
S.S
4.44
4.39
3.29
3.25
Temp
C°c)
67.8
66.8
76.5
75.25
79
76. 5
Moisture
(% Vol.)
24.51
26.0
32.9
35.06
40.49
40.57
xlO2
15.30
15 .35
16.0
19.0
16.6
18.5
Liquid Temp.
C°C)
In
19
18
19
19
19
20
Out
73.5
69
79
78
Scrubber
Press
Drop
(cm W.C.)
42 .04
41.9
42.54
40. S
45.6
42.96
Run
No.
86
87
88
89
90
91
Part iculate
Load x 103 (g/DNm3)
In
89.7
131
97.2
76 .74
159
227
Out
5 .2
7 .2
11.0
3.9
17
22.4
d
Pg
In
2.2
1.47
1.50
1.48
1.51
1.8
Out
1.15
0.81
1.39
1.0
1.0
1.06
0
g
In
2.2
1 .5
2.1
2.1
1.9
1.8
Out
2.1
1.8
2.2
1.8
1 .6
1 .8
n.
i
xlO-6
5.6
1.4
1.13
10 .0
1 .1
0 .92
Pt
(%)
5.8
5.5
11.46
5.14
10.6
9.67
Table 5.A.6 FIVE PLATE FF/C SCRUBBER; OPERATING CONDITIONS AND PERFORMANCE
Note: Scrubber operating mode identical as in Table 5.A.5.
Scrubber inlet and outlet sampled simultaneously with Gelman Type A glass fiber
filters .
Run
No.
92
93
94
95
96
97
98
99
100
Gas Inlet Conditions
Flow
.DNm3,
mm
7.74
7.97
6.81
4.93
5.76
5.49
4.38
3.23
3.32
Temp
47
56
57
68
66.5
69
75
79
76.5
Moisture
('« Vol.)
10 .03
15.4
15.6
24.58
25.8
26.4
31.5
39.6
41 .6
xlO2
4.8
8 .3
8 .5
9.4
12.3
13.85
17.6
16 .0
19 .5
Liquid Temp
In
21
20
20
22
18
20
18
17.5
20 .4
Out
46
56
56
66
70
Particulate Load
x!03(g/DNm3)
In
204
322
237
126
129
195
175
128
235
Out
27 .4
38.3
34.5
5.3
7 .9
36.9
16.0
16.8
17
Scrubber
Press
Drop
(cm W.C.)
43.9
48 .1
40.4
40.9
39 .9
40.9
41.2
44 .2
43.4
Pt
m
13.4
11.9
14. 5
4.2
6.13
18.9
9 .1
13 .1
7 .3
131
-------
Table S.A.7.
FIVE PLATE FF/C SCRUBBER; OPERATING CONDITIONS
AND PERFORMANCE
Plate configuration: Five identical plates with 3.2 mm round
perforations. Free area = 91; Plate
active area = 9.29 x 10 2m2
Dust used: Titanium dioxide, -16 mesh, dry dispersed
Cold water introduced on the top plate, flowrate = 0.38 liters/sec
Dry steam introduced in the scrubbed gas at scrubber inlet and
under plate no. 4 (second from the top)
Run
No.
101
102
103
104
105
106
Gas Inlet Conditions
Flow
,DNm3,
lmin >
7.7
7.65
6.70
7.24
7.0
7.48
Temp
C°C)
42
42
48.5
48
48
48
Moisture
(% vol.)
7.35
7.43
10.49
9.82
9.46
9.15
xlO2
6.65
7.53
9.98
11.73
11.8
11.45
Liquid Temp.
C°c)
In
15
16
15
15
15.5
16.5
Out
43.5
43.5
54
52
50.0
52.5
Scrubber
Press
Drop
(cm W.C.)
36.9
45.7
34.9
41
42.3
41.6
Run
No.
101
102
103
104
105
106
Particulate
Load x 103(g/DNm3)
In
81.37
95.20
102.22
69.03
71.3
68. 7
Out
6.08
4.20
4 .36
1.96
2.6
1.27
d
Pg
In
1.39
1.48
1.48
1.70
1.6
Out
0.82
0.83
1.01
1.17
0 .84
a
g
In
1.8
2.0
2 .0
1.7
1.7
Out
1.6
1.9
2.1
1.8
1.6
n.
xlO'6
0.6
0 .9
1.2
0.3
3.36
Pt
(%)
7.5
4.4
4.27
2.84
3.65
1.8
132
-------
l.Oi
D.5
0.2
Run #2
0.5
pa
1.0
(pmA)
2.C
3.0
Figure 5.A.I Particle penetration versus
aerodynamic diameter, five
plates.
0. 5
0.
0. 3
0.1
0.05
0.03
0.015
0.5
1.0
2.0
3.0
dpa(ymA)
Figure 5.A.2 Particle penetration versus
aerodynamic diameter, five
plates .
0.06
0.04
0.03
0.02
; o.oi
Run »7
Run »6
0.3
0.5
pa
1.0
(ymA)
2.0
3.0
Figure 5.A.3 Particle penetration versus
aerodynamic diameter, five
plates.
0.06
0.04
0,02
«0.01
0.005
Run »8
Run »9
0.5
pa
1.0
(ymA)
3.0
Figure 5.A.4 Particle penetration versus
aerodynamic diameter, five
plates.
133
-------
1.0
2 0.5
0.1
0.07
Run »10
1.0
dpa[ymA)
2.0
3.0 4.0
Figure 5.A.5
Particle penetration versus
aerodynamic diameter, four
plates.
0.6
0.3
0.2
0.1
0,05
Run #16
Run #12
0.4
Figure 5.A.6
1.0
2.0
3.0
Particle penetration
versus aerodynamic dia-
meter, four plates.
0.3
0.2
50.15
, o.i
o
H
IT, 0.05
0.02
Run #13
0.4
0.6
Figure 5.A.7
pa
1.0
(umA)
1.5 2.0
3.0
Particle penetration
versus aerodynamic dia-
meter, four plates.
0.3
0.2
r0.15
5
JO.l
5
c
j 0 . 0 5
j
j
j
"0.03
t,
c
LH
0.015
Run #15
Run #14
0.4
Figure 5.A.
pa
1.0
(ymA)
1.5 2.0
3.0
Particle penetration ver-
sus aerodynamic diameter,
four plates.
134
-------
0.3
0.2
,0.15
o.i
« 0.03
E-
0.015
0.3
0.6
pa
1.0
CymA)
1.5 2.0
3.0
Figure 5.A.9 Particle penetration versus
aerodynamic diameter, four
plates.
0. 7
0.4
. 15
0.3
0.05 i i
Run #19
0.6 1.0
2.0 3.0
Figure 5.A.10 Particle penetration versus
aerodynamic diameter, four
plates .
0.6
0.5
0.4
0.3
.0.2
,0.05
0.04
0.03
0.02
0.3
Run »22
I ' ' ' '
0.6 1.0
2.0 3.0
Figure 5.A.11 Particle penetration versus
aerodynamic diameter, four
plates.
1.0
0.7
£0.4
S
I 0.3
PJ
00.2
E-i
Pi
<
a.
0.1
Run 1*25
0.2 0.3
pa
0.6
(ymA)
1.0
2.0
Figure 5.A.12 Particle penetration versus
aerodynamic diameter, four
plates.
135
-------
ii 0.7
o 0.4
H 0.3
0.2
0.2
Run 129
0.4 0.6 l.t
Figure 5.A.13 Particle penetration versus aero
dynamic diameter, four plates.
0.4
! 0.3
0.1
.05
Run »32
D.3 0.4
0.6
d
Figure 5.A.14
1.0
(umA)
2.0 3.0
Particle penetration versus
aerodynamic diameter, four
plates.
(-0.4
< 0.2
0.06
Run »3S
I
I
0.3 0.4 0.6 1.0 1.5 2.0 3.0
d (umA)
Figure 5.A.15 Particle penetration versus
aerodynamic diameter, four
plates.
0.1
; 0.07
'0.05
0.03
0.3
Run «38
Run »36
0.6
d
1.0
(umA)
Figure 5.A.16
pa
Particle penetration versus
aerodynamic diameter, four
plates.
136
-------
0.6
0.4
0.3
0.2
o.i
0.07
0.04
.
0.02
0.01
0.2 0.3
0.6
1.0
2.0
Figure 5. A. 17 Particle penetration versus
aerodynamic diameter, four
plates .
1.0
-•0.5
O
f-
0.3
i 0.2
0.1
Run «48
_L
0.3
Figure 5.A.18
1.0 2.0 3.0
dpa[umA)
Particle penetration versus
aerodynamic diameter, four
plates.
l.C
0.7
• 0.5
,0.3
1.2
« 0.1
0.0
0.3
Run »52
Run
0.5
1.0
"pa
'.0
S.O
E- ,,rP 5 A 19 Particle penetration versus
Figure S.A.iy aerodynamic diameter, four
plates.
0.5
G 0.3
0.05
0.0
I I I I I I
0.3
Run »57
i I I i i I
1.0
2.0 3.0
d (ymA)
pa
Figure 5.A.20 Particle penetration versus
aerodynamic diameter, four
plates.
137
-------
1.0
60.5
0. 3
0.2
0.1
0.05
0.3
Run »60
Run »66
1.0
1.5 2.0
3.0
d (ymA)
Figure 5.A.21 Particle penetration versus
aerodynamic diameter, four
plates.
1.0
0.5
0.3
0.15
H
p;
< 0.1
0. 06
Run #61
Run «68
0.3
Figure 5.A.22
1.0 1.5
dpa(umA)
3.0
Particle penetration versus
aerodynamic diameter, four
plates.
1.0
0.5
o
H
'0.3
0.2
0.1
0.05
0.6
0.3
Figure 5 . A. 23 •-
pa
1.0
OmA)
1.5
3.0
Particle penetration versus
aerodynamic diameter, four
plates.
; o. 2
0.1
0.05
0.03
Run »73
Run »74
0.3
Figure 5.A.24
pa
1 .0
(umA)
1.5
3.0
Particle penetration versus
aerodynamic diameter, four
plates.
138
-------
5 0.2
S 0.1
0.03
Run »70
0.3
Figure 5.A.2S
pa
1.0
(ymA)
1.5
3.0
Particle penetration versus
aerodynamic diameter, four
plates.
1.0
0. 5
yo.3
oo. 2
5-
30.1
0.05
0.03
I I I I I
I I I I I I I I I
0.3 0.5 1.0 2.0 3.0
dpatvimA)
Figure 5.A.26 Particle penetration versus
aerodynamic diameter, five
plates.
0.3
0.2
-0.1
. 0.05
0.02
0.3
»80
0.5
1.0
2.0 3.0
Figure 5.A.27
pa
Particle penetration versus
aerodynamic diameter, five
plates.
0.5
z 0.3
o
0.2
0.1
0.05
0. 03
Run 081
0.3
0.5
1.0
2.0
3.0
pa"
Figure 5.A.28
Particle penetration versus
aerodynamic diameter, five
plates.
139
-------
0.4
SO.3
iO.Z
"0.1
0.05
0.03
).3
«85 _
I I I I I I I
0.5
1.0
2.0 3.C
Figure S.A.29 Particle penetration versus
aerodynamic diameter, five
plates.
0.2
0.1
C-0.05
SO. 03
JO.02
0.01
0.3
I I I I I
0.5
1.0
2.0
3.0
dpa(vmA)
Figure 5.A.30 Particle penetration versus
aerodynamic diameter, five
plates
0.2
1.1
-0.05
30.02
0.01
0.3
I I I 1 I I I
Run »88
I I I
0.5
Figure 5.A.31
pa
1.0
(ymA)
3.0
Particle penetration versus
aerodynamic diameter, five
plates.
0.4
'0.1
B. 0.05
. 0.03
0.3
I I I I I
Run If 90
Run »9
I I I I |
0. 5
1.0
(ymA)
2.0
3.0
Figure 5.A.32
pa
Particle penetration versus
aerodynamic diameter, five
plates.
140
-------
0.5
0.3
0.2
0.1
a. 0.05
0.03
Run »101
I I I I I
0.3
0.5
l.t
2.0
3.0
dpa(pmA)
Figure 5.A.33 Particle penetration versus
aerodynamic diameter, five
plates, steam under «4.
0.6
0.3
o
HO.2
0.1
;o.os
0.03
Q.02
Run K102
0.3
0.5
pa
1.0
(umA)
2.0
3.0
Figure 5.A,34
Particle penetration versus
aerodynamic diameter, five
plates, steam under »4.
00.2
! 0.1
^ 0.05
0.0
.0 «—
0.3
Run »103
I ' ' ' ' '
0. 2
0.5
1.0
3.0
d (ymA)
Fieure 5.A.35 Particle penetration versus
8 aerodynamic diameter, five
plates, steam under "4.
<0.05
JO.03
0.0.02
0.01
0.3
0.5
1.0
2.0
3.0
pa>-
Figure 5.A.36
Particle penetration versus
aerodynamic diameter, five
plates, steam under #4.
141
-------
0.4
0.3
0.2
o
i—i
H
U
I
I-U
PH
u
0.05
0.03
0.02
0.01
I I
0.3
III!
Run #105
J I I _J 1 1
0.5
1.0
d fymA)
LH -1
2.0 3.0
Figure 5.A.37 Particle penetration versus
aerodynamic diameter, five
plates, steam under #4.
142
-------
APPENDIX 5.B
HORIZONTAL SPRAY FF/C SCRUBBER
OPERATING CONDITIONS AND PERFORMANCE
143
-------
Table 5 B.I HORIZONTAL SPRAY SCRUBBER; OPERATING CONDITIONS AND
PERFORMANCE
Dust used: Titanium dioxide, -16 mesh
Spray configuration: Cold water sprayed in all of the three
sections and drained out through a common
outlet. Thus, scrubber operated in the
single stage mode.
Inlet water flowrates: First Section: 1.05 liters/sec @ 2.67 kg/cm
Second Section: 1.09 liters/sec @ 2.67 kg/cmz
Third Section: 1.0 liters/sec @ 2.85 kg/cm2
Run
No.
1
2
3
4
5
6
7
Gas Inlet Conditions
Flow
r-25I3i
Lmin '
26.2
25.9
25.3
24.6
24.8
20. 8
22.0
Temp
C°c)
14.8
12.8
44.5
45.5
44.5
46.3
49.3
Moisture
(1 vol.)
0.6
0.6
9.5
10.0
9.9
9.9
9.6
Relative
Humidity
C*)
29
35
92
97
100
92
78
Liquid Temp.
C°c)
In
11
11
18
19
19
17
16
Out
9
9
20
24
24
21
21
Scrubber Pressure
Differences (cmW.C.)
APS
+ 0.9
+ 0.9
+ 0.9
+ 0.9
+ 0.9
+ 0.9
+ 0.8
APE
-0.7
-0.6
-1.1
-1.0
-1.0
-1.1
-0.7
APo
+ 0. 2
+ 0.2
-0.2
-0.1
-0.1
-0.2
+ 0.1
Run
No.
1
2
3
4
5
6
7
Particulate
Load x 103 (g/DNm3)
In
192.0
180.0
106.2
91.1
107.6
138.1
53.3
Out
84.0
84.0
8.3
11.9
11.1
13.3
3.5
d
PS
In
1.00
1.13
1.09
0.99
Out
1.00
1.10
0.96
0.95
o
In
2.0
1.9
2.0
1.7
Filter run
Filt
Filt
er run
er run
a
Out
1.8
1.6
1.4
1.6
ni
xlO"6
6.8
4.4
3.2
1.0
q1
xlO
0.5
0.5
0.5
0.5
0.5
Ft
43.8
46.7
7.8
13.1
10.3
9.6
6.6
Note: APg : pressure difference across the scrubber
APg : pressure difference across the entrainment separator
APQ : overall pressure difference, AP APp ,
positive sign denotes pressure gain while pressure
loss is denoted by a negative sign.
144
-------
Table 5.B.I (continued)
Run
No.
8
9
10
11
12
13
14
15
Gas Inlet Conditions
Flow
,DSaJ
^min^
22.9
22.8
23.7
23.0
22.3
21.9
22.3
23.3
Temp
C°c)
57.3
57.0
58.0
57.5
64.5
66.5
67.0
67.8
Moisture
C% vol.)
15.6
15.7
16.6
16.8
23.3
25.7
25.5
25.5
Relative
Humidity
Ci)
86
86
86
90
90
90
89
85
Liquid Temp.
C°C) .
In
20
21
21
20.5
22
22
23
23.5
Out
25
27
26
25.5
40
43
45
44.5
Scrubber Pressure
Differences (cm W.C.)
A?S
+ 0.9
+ 0.8
+ 1.0
+ 0.9
+1.0
+ 1.0
+ 1.0
+ 1.1
ME
-0.9
-0.9
-1.1
-0.9
-1.0
-1.0
-1.0
-1.0
AP0
___
-0.1
-0.1
---
---
---
---
+ 0.1
Run
No.
8
S
10
11
12
13
14
15
Particulate
Load x 10BCg/Wta35
In
72.8
110.6
113.4
97.3
58.7
46.6
136.0
154.7
Out
5.4
5.1
5.2
3.7
2.3
2.6
7.6
7.5
d
In
1.13
1.31
1.36
1.29
Out
0.96
°e
In
1.7
Filter
0.92)1.9
Filter
Filter
1.00
0.90
2.0
1.9
Filter
Out
1.6
run
1.6
run
run
1.6
1.6
run
n±
xlO"6
2.0
1.5
0.7
1.9
q'
xlO
0.9
0.9
1.0
11. 0
1.5
1.6
1.6
1.7
Ft
7.5
4.6
4.5
3.8
3.9
5.6
5.6
4.8
Table 5.B.I (continued)
Run
No.
16
17
18
19
20
21
22
23
Gas Inlet Conditions
Flow
(™lj
LminJ
21.1
17.2
17.7
17.7
21.3
19.8
19.2
22.2
Temp
(°C)
68.5
73.5
73.0
74.0
75.5
81.5
79.5
78. 0
Moisture
C% vol.)
27.7
34.1
35.0
34.0
28.8
32.7
33.6
42.5
Relative
Humidity
W
90
91
95
89
70
62
70
95
Liquid Temp.
C°c)
In
22
25
27
27
22
27
25.5
24
Out
46
50
55
52
44
S3
48
49
Scrubber Pressure
Differences (cm W.C.)
APS
+ 0.9
+ 0.8
+ 1.0
+ 0.9
+1.0
+ 1.0
+1.0
+ 1.0
APE
-0.9
-0.7
-0.7
-0.6
-0.9
-0.7
-0.8
-0.6
AP0
+ 0.1
+ 0.3
+ 0.3
+ 0.1
+ 0.3
+ 0.2
+ 0.4
Run
No.
16
17
18
19
20
21
22
23
Particulate
Load x 10
In
147.0
77.1
102.6
75.8
105.1
73.6
79.8
68.9
3(g/Difei3)
Out
5.8
4.3
3.5
3 . 5
24.7
17.0
17.2
6.13
L_Jj>2
In
1.30
1.32
1.40
1.21
1.11
1.45
Out
0.94
1.09
%
In
1.9
2.4
Out
1.7
1.5
Filter run
1.05
1.9
1.5
Filter run
0.98
0.97
0.98
2.0
2.2
2.2
1.7
1.7
1.6
ni
xlO"s
2.0
3.4
0.8
1.6
3.7
1.3
q1
*11)
1.8
2.5
2.5
2.8
2.0
2.5
2.9
3.6
Ft
3.9
5.6
3.4
4.6
23.5
23.1
1.6
8.9
-------
Table 5.B.2 HORIZONTAL SPRAY SClUjBBER;
AND PERFORMANCE
OPERATING CONDITIONS
o\
Dust used: Titanium dioxide, -16 mesh
Spray configuration: Cold water sprayed in all of the three
sections and drained out through a common outlet .
Thus, scrubber operated in the single stage mode.
Inlet water flow rates: First section - 1.05 ft/sec @ 2.67 Kg/cm2
Second section - 1.09 I/sec @ 2.67 Kg/cm2
Third section - 1.0 fc/sec @ 2.85 Kg/cm2
Run
No .
24
25
26
27
28
29
30
31
Gas Inlet Conditions
Flow
, I!Mn,3
'•nun'
23.7
23.0
23.9
24. I
24
23
22.8
23
Temp
C°C)
10
12
11.5
11
11
46
45.5
45
Moi s ture
C'. vol.1
0.76
1.0
1.1
1.4
1.1
10.1
10.3
10
Relative
Humidity
m
71
68
96
77
77
95
97
100
-iquid Temp.
(°C)
In
8
8
8
8
9
16
15.5
14.5
Out
9.5
9.5
9.5
9.5
10.5
23.5
21.5
22.5
Scrubber Pressure
Differences (cm W.C.)
APS
0.8
0.8
0.8
0.8
0.8
0.8
0.8
0.8
4Pt
1.0
1.0
1.0
1.0
1.0
0.9
0.9
1.0
4P0
-0.2
-0.2
-0.2
-0.2
-0.2
-0.1
-0.1
-0.2
Run
Mo.
24
25
26
27
28
29
30
31
Particulate
Load x 10
In
122.4
52.3
97.4
98 .4
106
90.2
104.0
100
1 (g/DNm')
Out
47.43
21.7
37.8
41.6
46.6
9.41
9.47
11.9
dPE
In
1.2
1.07
1.05
1.2
1.06
Out
1.02
1.04
0.96
1.06
1.0
°£
In
1.7
1.8
1.8
1.9
1.8
Out
1.6
1.7
] .7
1.6
1.7
"l
xlO'6
0.6
1.9
2.3
1.5
1.9
q'
xlO
--
0.48
0.50
0 .50
PT
0.39
0.42
0.38
0.42
0.44
0.10
0.92
0.12
(cont inued)
Run
No.
32
33
34
3S
36
37
38
39
40
Gas Inlet Conditions
Flow
(ii»j
'•mm-'
22.1
21.9
21.7
20.7
20.3
19.5
18.8
19.6
19.6
Temp
C°c)
56
57
56
66
65.5
82.5
73.5
84.5
84.5
Moisture
CS vol.)
17.3
17.4
16.4
26.04
26.9
36.3
1.2
35.1
36
Relative
Humidity
CM
97
90
95
95
100
66
90
60
57
Liquid Temp .
C°C)
In
16
18
22
23
19
23
24
22
22
Out
28
31.5
34
38
38
49
48.8
47.5
47.5
Scrubber Pressure
Differences (cum W.c.)
ips
0.8
0.8
0.9
0.8
0.8
0.9
0 .8
0 .9
0.9
APr,
0.8
0 .8
0.9
0.8
0.8
0.8
0.8
0.7
0.7
APQ
0
0
0
0
0
0 .1
0
0.2
0.2
Run
No .
32
33
34
35
36
37
38
39
40
P a r 1 1 c u 1 ate
Load x 103(g/D\m3)
1 In
133
128
101
121 .0
158.0
131.0
128.4
146.0
144.0
Out
6.02
5.98
9.29
8.59
6.37
22.4
10 .0
22.1
22.1
d
In
1.23
1 .04
1.01
1.06
1.21
1 .16
Out
0.9
Filtei
0.84
0.79
Filtei
0.88
0.77
0.96
Filtei
a
In
1.9
Ru
1.5
1.6
Ru
1.8
1.9
1.8
Ru
Out
1.9
1.5
1.7
1 .7
1.62
1.5
n -
i
L xlO"'
2.0
1 .3
1.9
3.1
2.1
2.3
q'
1.01
0.97
1.01
1 .9
1 .75
2.20
2.45
2.65
2.27
Pt
0.045
0.047
0.092
0.071
0 .040
0.17
0 .078
0.15
0.15
-------
Table 5.B.3. HORIZONTAL SPRAY SCRUBBER; OPERATING CONDITIONS
AND PERFORMANCE
Dust used: Titanium dioxide, -16 mesh
Spray configuration: Scrubber operated in single stage mode.
The number of nozzles was decreased to obtain the
lower water flowrates, maintaining the small spray
drop -diameter
Inlet water f lowrates: 0.76 5,/sec in each section
Run
No.
41
42
43
44
45
46
47
48
49
SO
Gas Inlet Conditions
Flow
(EW?
^min'
23.37
22.32
22.2
22.4
21.7
22.0
22.1
20.8
20.4
20.5
Temp
C°C)
11
45
45
46
56
57
56
66
68
66
Moisture
C% vol.)
.77
10.0
9.8
10.1
16.5
16.9
16.9
25.6
26.7
26.8
Relative
Humidity
m
56
100
97
94
95
95
98
95
91
98
Liquid Temp.
C°C)
In
10.5
18.4
14.8
13.9
18.8
18.5
18.1
20.6
22.0
21.8
Out
10.1
26.4
12.5
22.7
31.3
31.3
30.8
40.0
42.5
41.3
Scrubber Pressure
Differences (Cm W.C.)
ips
0.8
0.7
0.7
0.7
0.8
0.8
0.8
0.8
0.8
0.8
APE
-1.0
-0.9
-0.9
-0.8
-0.8
-0.8
-0.8
-0.8
-0.8
-0.8
apo
-0.2
-0.2
-0.2
-0.2
---
Run
No.
41
42
43
44
45
46
47
48
50
Part iculate
Load x 10
In
72.3
77.1
99.8
121.5
72.4
84.2
97.8
66.4
77.2
3Cg/DNm!)
Out
20.2
9.7
11.5
10.1
4.1
2.6
5.2
2.8
3.3
d
In
1.5
.78
.94
1.05
1.1
.92
.96
Out
.82
.64
.85
- Filti
1.05
.9
- Filti
1.1
.96
a
s
In
2.9
2.0
1.8
r Ru
1.6
1.8
r Ru:
1.6
1.7
Out
1.5
1.7
1.6
1.6
1.7
2.2
1.7
ni
xlO-6
1.0
7.7
2.9
1.11
1.73
1.5
1.7
t
q'
xio
.48
.49
.52
.94
.98
.99
1.66
1.78
FT
27.9
12.6
11.5
8.3
5.7
3.0
5.3
4.25
4.27
Table 5.B.4. HORIZONTAL SPRAY SCRUBBER; OPERATING CONDITIONS
AND PERFORMANCE
Dust used: Titanium dioxide, -16 mesh
Spray configuration: Scrubber operated in the single stage
mode. The lower water flowrates were sprayed
through same number of nozzles, thus the spray
drops were of larger size.
Inlet water f lowrates: 0.76 5,/sec in each section
Run
No.
51
52
53
54
55
56
57
58
Gas Inlet Conditions
Flow
JHfaj
vminj
23.7
23.7
23.8
23.7
24.6
24.3
21.9
22.1
Temp
C°c)
17
15
10
12
14
10
46
47
Moisture
(_l vol.)
1.4
1.2
1.1
1.1
1.0
0.9
1.4
1.3
Relative
Humidity
m
64
66
82
73
65
79
94
92
Liquid Temp.
C°c)
In
9.6
10.4
9.6
10.4
10.4
10.4
17.2
16.9
Out
11.5
11.5
10.4
11.2
11.3
10.8
26.7
26.7
Scrubber Pressure
Differences (cm W.C.)
APS
0.4
0.4
0.4
0.4
0.9
0.9
0.4
0.5
APE
-0.9
-0.9
-0.8
-0.9
-1.0
-1.0
-0.8
-0.8
APQ
-0.5
-0.5
-0.4
-0.5
-0.1
-0.1
-0.4
-0.3
Run
No.
51
52
53
54
55
56
57
58
Particulate
Load x 103(g/DNm3)
In
91.3
60.0
81.3
57.2
72.8
77.3
75.8
102.9
Out
56.2
45.1
49.4
39.9
31.4
33.8
16.1
24
d
In
1.06
.98
1.01
1.03
Out
1.04
Filte
Filte
1.03
.96
.94
Filte:
Filte]
cc
~T5~
1.8
Run
Run
1.7
1.8
1.7
Run
Run
Out
1.6
1.6
1.6
1.6
ni
xlO s
2.0
1.3
1.4
1.5
1'
vin
...
-._
...
-_.
.-_
.47
.47
61.6
75.2
60.8
69.7
43.2
43.7
21.2
23.3
-------
Table 5.B.4 (continued)
Table S . B.4 (continued)
Run
No.
59
60
61
62
63
64
65
66
DNmj
kmin'
22
21.9
21.7
21.4
21.5
21.3
21.5
20.8
Gas Inlet Condit
C°C)
47
47
57
58
57
58
57
66
(I vol.)
1.3
1.4
.56
.59
.61
.57
.60
.83
ions
Humidity
CO
92
95
90
88
93
90
95
91
Liquid Temp.
In
17 .2
16.6
15.6
16.7
16.9
16
14.1
19.6
Out
2S.5
21.9
28.8
30
30
28.8
28.1
41.9
Scrubber Pressure
APS
0.5
0.4
O.S
0.5
0.5
0.5
0.5
0.5
4PE
-0.8
-0. 7
-0.7
-0.7
-0.8
-0.8
-0.8
-0.8
AP0
-0.3
-0.3
-0.2
-0.2
-0.3
-0.3
-0.3
-0.3
Run
No.
67
68
69
70
71
72
73
74
Gas Inlet Conditions
Flow
t-D»)
'•mm-'
19.9
20.9
20.8
20.5
19.4
19.8
19.3
19.1
Temp
c°c)
68
66
67
67
73
73
74
73
Mo is ture
(t vol.)
.68
.84
.62
.62
1.2
.8
1.2
1.1
Relative
Humidity
m
86
95
92
96
94
96
92
96
Liquid Temp.
C°C)
In
18.9
18.9
18
18.3
22
20.8
22.3
22.2
Out
44.4
42.5
40.6
39.4
49.4
49.4
50.5
49.3
Scrubber Pressure
Differences (em W.C.)
APS
0.5
0.5
0.5
0.5
0 .6
0.5
0.6
0.6
APE
-0.8
-0.8
-0.7
-0.7
-0.7
-0.7
-0.7
-0.8
AP0
-0.3
-0.3
-0. 2
-0.2
-0.1
-0.2
-0.1
-0. 2
oo
Run
No.
59
60
61
62
63
64
65
66
Particulate
Load x 10
In
83.2
66.6
86. 7
86.6
108.6
93.8
64.3
94.4
'(g/DNm3)
Out
25.7
14.6
21.3
14.9
21.9
10.1
7.9
9.3
'S*
In
1.07
1 .1
1.14
1.15
1.11
1.15
Out
.91
.95
.92
Filte:
.94
.92
Filtei
.89
°B
In
1.7
1.8
1.6
Run
1.7
1.7
Run
1.7
Out
l.S
1.6
1.7
1.6
1.5
1.5
ni
x 1 0 " b
.98
1.6
1.0
1.4
l.S
1.4
q'
xin
.49
.49
.92
.97
.99
1.0
1.1
1.5
PT
30.9
21 .9
24.5
17.2
20.2
10.8
12.3
9.8
Run
No.
67
68
69
70
71
72
73
74
Particulate
Load X 103 (g/nMnJ)
In
82.7
111.2
109.1
115.5
99.3
122.6
129.2
117.9
Out
10.5
21 .8
10.7
13.8
13
10.3
12.7
9.7
d
In
1.25
1.2
1.18
1.13
Out
.91
Filter
Filter
.95
.92
.95
o
In j Out
1.7 1.5
Run
Run
1.8 1.6
1.8 1.6
1.8 1.5
Filter Run
Filter Run
n-
xiO"
.78
1.4
1.4
2.0
q'
xlO
1.5
1.7
1.8
1.9
2.4
2.5
2.6
2.7
PT
12.7
19.6
9.8
12
13.1
8.4
9.8
8.2
-------
Table 5.B.5 HORIZONTAL SPRAY SCRUBBER; OPERATING CONDITIONS AND PERFORMANCE
Dust used: Titanium dioxide, -16 mesh
Spray configuration: Scrubber operated in three stage mode. Cold water
sprayed into the first section. The drained water of section 1
resprayed into section 2 and the drain of section 2 sprayed into
section 3. Thus, the scrubber is operated in co-current scheme.
Spray water flow rates: First Section: 1.05 liters/sec @ 2.67 Kg/cm2
Second Section: 1.09 liters/sec 8 2.67 Kg/cm2
Third Section: 1.0 liters/sec @ 2.85 Kg/cm2
Table 5.B.5 (continued)
Run
No.
75
76
77
78
79
Gas Inlet Condition
Flow
C-HB3)
24.1
24.4
24.4
24.4
24.7
Temp
CC
17
21
23
25
18.5
Moisture
% vol.
0.13
0.88
2.7
2.7
0.5
Rel.
%llun.
42
60
92
95
22
Liauid Temperature
1st Section
In
12.5
13
13.5
14.5
•10
Out
12.5
13
13.5
14.5
10
2nd Section
In
12.5
13
13.5
12
10.5
Out
11.5
12
12
12.5
9
3rd Section
In
13
13.5
14.5
15.3
10.5
Out
11.5
11.8
12
12.5
8
Scrubber Pressure
Differences (cm W.C.)
APS
0.8
0.9
0.8
0.8
0.9
APE
1.0
1.0
1.0
1.0
1.0
AP0
-0.2
-0.1
-0.2
-0.2
-0.1
Run
75
77
79
LoadxlO3
In
223.1
245.2
189.9
(g/Dla»3)
Out
84.1
85.6
82.1
I
V' i
In
• 0.95
1.0
1.1
articulate
mA
Out
1.0
2.1
1.2
. ac
In
2
2.1
2
Out
1.6
1.6
1.8
5.1
3.9
4.7
qio::
0
0
0
Pt
0.38
0.35
0.43
Note: APS: Pressure difference across the scrubber
APg: Pressure difference across the entrainment separator
APg: Overall pressure difference, APg-APp, positive sign denotes pressure gain while
pressure loss is denoted by a negative sign.
Run
No.
80
81
82
83
84
85
86
87
88
Gas Inle Condition
Flow
.-OKIE 3,
Lmn J
23.3
23.2
23.0
22.8
22.3
22.3
22.2
22.2
22. S
Temp
°C
46
45
46.5
46
56.5
55.5
55.5
55 ;8
56.5
Moisture
% VOl.
10
9.7
9.5
9.7
17.1
16.1
16.1
16
16.3
Rel.
SHum.
95
97
97
95
92
96
96
92
92
Liauid Temperature
1st Section
In
15.5
12.5
14
18.5
18
18
17
17
17
Out
24.5
22.5
23.5
26.5
34.2
33
35
32
33
2nd Section
In
20.5
18.5
21.5
24
28.5
22.5
27
28.5
19.5
Out
25.5
23.5
25.0
28
35.5
33.5
35.5
33
34
3rd Section
In
25.5
23.5
25.0
28.5
34.5
32
32.5
33
31.5
Out
25.5
23.5
25.0
28
35.5
33.5
35.5
33
33.5
Scrubber Pressure
Differences (cut W.C.)
APS
0.9
0.8
0.8
0.9
0.8
0.8
0.8
0.9
0.9
APE
0.9
0.9
0.9
0.9
0.8
0.8
0.8
0.9
0.9
4PQ
0
-0.1
-0.1
0
0
0
0
0
0
80
81
84
85
86
88
LoadxlO"
In
152.0
196
162.2
207
161
186
Cg/DHm3)
Out
22.3
19.6
9.7
16.9
13
15.0
I
V- I
In
1.3
0.87
1.3
1.2
1.2
articulate
mA
Out
0.87
0.97
i ter
- Filter -
0.94
0.94
0.92
o
E
In
2.0
2.2 .
Run
— Run
1.8
1.8
1.7
Out
1.5
1.6
1.5
1.5
1.6
2.4
22.0
2.1
2.1
2.3
q1
0.46
0.45
0.84
0.87
0.87
0.9
Pt
0.147
0.10
0.061
0.082
0.081
0.081
-------
Table 5.B.S (continued)
Run
No.
89
90
91
92
93
94
95
96
Gas Inlet Condition
Flow
. DNm\
lmTn" >
20.1
20.1
19.6
20.7
18.2
19
18.8
18.7
Temp
0 C
66
65.5
67
67
72.5
72.5
72.5
73
Moisture
°f VOl .
25.6
24.2
27.2
26.4
35.7
35.7
36.4
33.8
Rel.
Hum .
94
94
95
92
100
95
100
91
Liauid
1st Section
In
17.5
17.5
17.5
16.5
16.5
17
17
17
Out
42 .5
42
43.5
41
53.5
50.5
50.5
54
remperature
2nd Section
In
34
34.5
33
34.5
44.5
40.5
41
42.5
Out
45.5
43
46
40
51.5
48.5
50
51
3rd Section
In
41
40.5
40.5
40
51.5
48.5
50
51
Out
45.5
42.5
46
40
55
53
54.5
55.5
Scrubber Pressure
Differences (cm IV. C.)
APS
0.8
0.8
0.8
0.8
0.8
0.8
0.9
0.9
APE
0.7
0.8
0.7
0.8
0.7
0.7
0.9
0.8
AP0
0.1
0
0.1
0
0.1
0.1
0
0.1
Run
89
91
92
95
96
LoadxlO3
In
173
158
120
186
168
(g/DNm3)
Out
14.7
12.7
6.48
12.4
15
P
V' V
In
1.2
1.1
1.3
1.1
1.2
articulate
mA
Out
0.97
1.05
0.95
.
0 .94
0.9
°1,
In
1.8
1.8
1.7
2
1.8
Out
1.5
1.5
1.6
1.5
1.6
n X 10 "6
2.2
2.6
4.1
5.4
2.8
q1
x 10
1.35
1.55
1.53
2.32
2.07
Pt
0.085
0.08
0.054
0.067
0.089
Table 5.B.6 HORIZONTAL SPRAY SCRUBBER; OPERATING CONDITIONS AND PERFORMANCE
Dust used: Titanium dioxide, -16 mesh
Spray configuration: Scrubber operated in three stage mode. Cold water sprayed into
the third section and the scrubber operated in counter-current scheme.
Spray water flow rates: First section: 1.05 E/sec 8 2.67 kg/cm2
Second section: 1.09 I/sec 6 2.67 kg/cm2
Third section: 1.0 H/sec 8 2.85 kg/cm2
Run
No.
97
98
99
100
101
102
Gas Inlet Condition
Flow^
, DHm3
'•mm '
23.4
24.0
23.4
23.2
22.8
23.2
Temp
0 C
17.3
10.5
20
21
23
13
Moisture
" vol .
10.9
10.5
20
21
23
13
Rel.
ilium.
50
77
41
39
34
54
Jiauid Temperature
1st Section
In
7 .7
10.7
9.9
9.2
9.1
8.5
Out
12.0
10.4
11.2
12.0
10.7
9.3
2nd Section
In
7.2
9.9
9.9
9.1
9.9
8 .9
Out
11.2
10.1
9.9
11.7
9.7
9.3
3rd Section
In
10.1
12.5
11.7
12.3
13.2
12.3
Out
11.3
10.4
10.9
12.8
11.5
9.6
Scrubber Pressure
Differences (cm w.C.)
APS
0.9
0.4
0.9
0.8
0.8
0.8
AP,;
-1.0
-1.0
-1.0
-1.0
-1.0
-1.0
Al'o
-0.2
-0.6
-0.1
-0.2
-0.2
-0.2
Mo
97
98
99
100
101
102
LoadxlO 3
In
64 3
60 3
100.6
122 8
95.3
79 .4
(g/DNm3)
Out
28 7
37 1
44.5
51 3
41.4
36 .0
I
dPB' I
In
0.98
0.96
0.96
art icul ate
mA
Out
0.92
0.9
0.88
°E
In
1.8
1.7
1.7
Out
1.5
1.5
1.5
Aj X 10 '
2.6
2.0
1.7
q'
x 10
Pt
44.2
43.4
45.3
150
-------
Table s.B.6 (continued
Run
No.
103
104
105
106
107
108
109
110
111
Gas
Flow
JjiTn '
23.8
22.3
22.8
22.9
22.7
22.5
21.7
21.5
21.4
Inlet rnndirirn
Tern;
11
46
46
46.5
46 .5
47.5
56.5
56
56.5
Moisture
t vol.
1.1
10.0
10.0
10.0
10.3
10.2
16.0
16.4
16.8
Rel
Hum
77
94
94
92
95
89
• 90
95
95
Liquid Tpmrterature
1st Section
In
18.1
24.5
25.1
23.5
24 .5
25.9
30.5
31.3
30.6
Out
12.8
31.5
29.8
31.5
30.0
30.5
43.8
44.4
43.8
2nd Section
In
17.3
22.9
23.5
20.8
21.9
20.8
26.3
27.5
27.5
Out
12.8
29.0
26.0
26.7
26.5
26.5
37.5
38.8
40.0
3rd Section
In
19.7
18.7
17.1
14.4
18.1
13.3
14.4
16.7
17.3
Out
12.5
26.7
24.3
24.0
24.3
22.9
30
31.3
32.5
Scrubber Pressure
Differences (cm W.C.)
APg
0.4
0.8
0.9
0.9
0 .9
0.9
0.8
0.9
0.9
AP£
-0.9
-1.0
-1.1
-1.0
-1.0
-1.0
-0.9
-0.9
-1.0
AP0
-0.5
-0.2
-0.2
-0.1
-Q.I
-0.1
-0.1
0.0
-0.1
Run
103
104
105
107
108
109
LoadxlO3
In
76.4
106.3
68.4
68.3
96.6
(g/Dl™3)
Out
49.8
29.8
16.0
11.5
13.6
I
V' i
In
0.96
0.94
1.0
0.94
1.1
'articulate
mA
Out
1.0
0.84
0.82
0.92
0.82
0
In
1.8
1.6
1.6
1.7
1.6
j
Out
1.6
1.5
1.5
1.6
1.6
n x 10 "6
i
2.1
2.4
1.2
1.7
1.2
q1
x 10
0.47
0.47
0.52
0.87
Pt
65.2
28.0
23.4
16.8
14.1
Table 5.B.6 (continued)
Run
No.
112
113
114
115
116
117
118
119
120
Gas Inlet Conditi
Flow
,DNm3.
tmTn '
21.1
21.5
20.4
20.8
20.1
19.9
20.2
19.3
19.6
Temp
56.5
57.5
66
66
66
68
67.5
74-
73
Moisture
% vol .
16.9
17.2
26.2
25.5
25.6
27.3
26.7
34.7
36.3
1
Rel.
Hum.
95
93
96
93
93
91
91
90
100
Liquid T
1st Section
In
31.9
33.1
43.8
43.8
47.0
45.6
45.0
52.3
50.5
Out
41.3
42.5
57.2
56.0
54.8
58.4
55.4
67.0
65.7
crcperature
2nd Section
In
30.0
30.0
38.8
38.8
40.0
42.5
40.0
48.8
48.8
Out
36.3
38,8
53.6
51.1
51.1
54.8
51.1
62.1
63.3
3rd Section
In
20.0
18.7
18.7
19.3
19.7
20.0
18.7
20.7
24.0
Out
35.6
30.6
42.5
41.3
40.0
43.8
41.3
52.3
52.3
Scrubber Pressure
Differences (cm 't.'.C.)
APS
0.9
0.9
0 .9
0.9
0.9
0.9
0.9
0.9
0.9
APE
-0.9
-1.0
-0.9
-0.9
-0.9
-0.9
-0.9
-0.9
-0.9
AI'Q
-0.1
o.o
-0.1
0.0
0.0
0.0
0.0
0.0
0.0
Run
No.
112
113
114
115
116
117
118
119
120
LoadxlO3
In
109.6
86.8
154.1
150.5
167.6
131.0
140.5
129.4
169.6
(E/DNm3)
Out
19.9
13.2
32 .6
23.5
24.1
P
Qpg' "
In
1.03
1.2
1.03
1.1
1.0
articulate
mA
Out
0.85
0.82
0.82
0.88
0.86
?
In
1.5
1.6
1.7
1.6
1.6
Out
1.5
1.5
1.6
1.5
1.5
1.3
0.7
2.5
2.1
2.6
q'
0.9
0.95
1.5
1.5
1.5
Pt
18.2
15.2
21.2
15.6
25.1
18.4
21.2
11.8
151
-------
Table 5.B.6 (continued)
Run
No .
121
122
123
Gas Inlet Condition
Flow
,DNm3,
^min '
18.1
19.4
19.1
Temp
°C
74
73.5
71
Moisture
°6 VOl .
36.3
36.3
33.2
Rel.
Hum .
94
96
98
Liquid Temperature
1st Section
In
47.5
48.1
49 .9
Out
64.5
64.5
63.3
2nd Section
In
43.8
43.8
45.6
Out
60.9
60.9
59.7
3rd Section
In
21.3
21.3
16.0
Out
50.0
49.9
48.8
Scrubber Prc.ssuie
Differences (cm IV. C.I
APS
0.9
0.9
0 .8
APE
-0.8
-0.9
-0.8
AP0
0.1
0.0
0.0
Run
No .
121
122
123
Part i cul ate
LoadxlO3
In
135.4
98.3
76.8
(g/DNm3)
Out
9.0
12.4
10.0
^pg > ymA
In
1.23
1 .12
1.05
Out
0.88
0.82
0.8
°c
In
1.8
1.7
1.7
Out
1 .6
1.5
1 .4
j^ x 10 -6
1. 7
1.4
1.2
x 10
2.5
2.5
3.0
Pt
6.7
12.6
13 .0
152
-------
0.5
0.1
RUN
1-0 2.0 3.0
0.05
0.02
1 ill
0.2
dpa,
Figure 5.B.I Particle penetration versus aero-
dynamic diameter, single stage
spray scrubber.
Figure S.B.2 Particle penetration versus aero-
dynamic diameter, single stage
spray scrubber.
O.Oll
_L
_L
0.05
.RUN »14
0.2
Figure 5.B.3
0.5
2.0 3.0 '4;0
pa.
0.5
d.
Particle penetration versus aerodynamic
diameter, single stage spray scrubber.
Figure 5.B.4.
'
Particle penetration versus aerodynamic
diameter, single stage spray scrubber.
153
-------
S- 0.1
5 0.05
0.2
RUN #19
RUN #17
pmA
0
Figure 5.B.5. Particle penetration versus aerodynamic
diameter, single stage spray scrubber.
1.0
0.5
0.03
Figure 5.B.6.
.RUN #21
RUN * 23
llll
RUN 122
2.0 3.0
V-
Particle penetration versus aerodynamic
diameter, single stage spray scrubber
1.0
.0.5
0.1
0.3
0.3
3.0
d , umA
pa'
Figure 5.B.7. Particle penetration versus aerodynami
diameter, single stage spray scrubber.
0.1
0.05
0.2
0.5
1.0
dpa, umA
Figure S.B.8.
Particle penetration versus aerodynamic
diameter, single stage spray scrubber.
154
-------
5 0.06
0.01
0.05
0.2
3.0
0.01
0.2
dpa, umA
0.5 1.0
d , pmA
Figure 5.B.9. Particle penetration versus aerodynamic Fi 5.B.10. Particle penetration versus aerodynamic
diameter, single stage spray scrubber. diameter, single stage spray scrubber.
0.3
0.1
0.05,
_L—I 1 I I I
0.4
0.1
RUN »37
0.5
0.2
1.0
3.0
dpa, umA
d , umA
pa'
Figure S.B.1Z. Particle penetration versus aerodynamic
diameter, single stage spray scrubber.
Figure S.B.ll.
Particle penetration versus aerodynamic
diameter, single stage spray scrubber.
155
-------
0.3
0.2
u
2 0.1
0.05
0.01
0.3
Figure 5.B.13
Run *42
pa
1.0
CumA)
2.0
3.0
Particle penetration versus
aerodynamic diameter, one
stage .
0. 2
'0.1
50.05
'0.02
0.01
Run «43
0.3
Figure 5.B.14
pa
1.0
(pmA)
2.0
3.0
Particle penetration versus
aerodynamic diameter, one
stage.
0.1
0.05
o
s-
^ 0.02
0.01
0.3
1.0
2.0
3.0
Figure 5.B.15 Particle penetration versus
aerodynamic diameter, one
stage.
0.06
0.05
0.04
0.03
0.02
0.01
0.005
0.3 0.5
1.0
d , umA
pa'
2.0 3.0
Figure 5.B.16 Particle penetration versus
aerodynamic diameter, single
stage.
156
-------
1.0
0.5
M 0.2
0.3
1.0
d
pa
2.0 3.0
Figure 5.B.17 Particle penetration versus
aerodynamic diameter, one
stage.
0.2U
0.1
0.3
1.0 2.0 3.0
Figure 5.B.18 Particle penetration versus
aerodynamic diameter, one
stage.
jj
i
1.1
0.5
0.2
0.1
0.3
Run »59
Run »60
I I I
1.0,
1.0
umA
2.0 3.0
•tage.
0.5
0.
0.
0.3
Run * 61
1.0
dpa, ymA
2.0
3.0
Figure 5.B.20 Particle penetration versus
aerodynamic diameter, one stage
157
-------
0.4
0.2
0.1
o.os
0.02
0.3
1.0
-,!,> U™A
2.C
3.0
Figure 5.B.21 Particle penetration versus
aerodynamic diameter, one stage.
0.4
0.3
X 0.2
0.1
0.05
0.03
0. 3
1.0 2.0 3.0
pa,
Figure 5.B.22- Particle penetration versus
aerodynamic diameter, one st
age.
0.3
0.1
).OS
0.02
Run »70
1.0
dpa, umA
2.0
3.0
1.0
0.5
0.1
0.3
Figure 5.B.24
RUN »75
RUN »77
RUN »79
0.5
3.0
pa,
Particle penetration versus aerodynamic
diameter, 3 stage co-current spray scrubber
Figure 5.B.23
Particle penetration versus
aerodynamic diameter, one stage.
158
-------
0.2
Figure 5.B.25
Particle penetration versus aerodynamic
diameter, 3 stage co-current spray scrubber.
RUN »86
RUN *88
0.5
d
Figure 5.B . 26
pa' •"'-
Particle penetration versus aerodynamic
diameter, three stage co-current spray
scrubber.
RUN 196
-•s.
RUN »95
Figure 5.B.27 Particle penetration versus aerodynamic
diameter, three stage co-current spray
scrubber.
Figure 5.B.Z8 Particle penetration versus aerodynamic
diameter, three stage co-current spray
scrubber.
159
-------
1.9
2 o.
0.2
0.1
Run »99
1.0
z
o
H
U
3
u,
z" 0.5
o
£ 0.4
a
I °'3
W
D-
UJ
3 0.2
f-
o;
<
cu
0.1
0.3
Figure 5.B.29
1.0 2.0 3.0
d , ymA
pa'
Particle penetration versus
aerodynamic diameter, three
stage counter - current.
0.4
0.3
0.2
0.1
0.05
0.3
Figure 5.B.31
1.0 2.0 3.0
dpa, ymA
Particle penetration versus
aerodynamic diameter, three
stage counter-current.
.03
Figure 5.B.30
1.0
2.0
3.0
pa>
Particle penetration versus
aerodynamic diameter, three
stage counter - current.
O.I
0.2
0.1
0.05
0.04
0.03
0.02
0.01
0.3
1.0
dpa, umA
2.0
3.0
Figure 5.B.32
Particle penetration versus
aerodynamic diameter, three
stage counter current.
160
-------
t.7
0.3 _
0.2 _
0.1 -
0.4
0.3
0.2
0.1
0.05
0.02
Run #123
1122
0.3
1.0
2.0 3.0
0.3
1.0
2.0
3.0
upa, ,v™
Figure S.B.33 Particle penetration versus
aerodynamic diameter, three
stage counter-current.
-y
Figure 5.B.34 Particle penetration versus
aerodynamic diameter, three
stage counter-current.
0.6.
0.4
0.3
0.2
0.
0.0
0.
0.3
1.0
dpa' umA
2.0
3.0
Figure 5.B.35- Particle penetration versus
aerodynamic diameter, three
stage counter-current
161
-------
APPENDIX 6.A
PROGRAM FOR CORRECTING PARTICLE
COLLECTION ON A SIEVE PLATE
163
-------
APPENDIX 6.A.
Program for Correcting Particle
Collection on a Sieve Plate
C THIS IS A F0RTRAN IV PROGRAM F0R CALCULATING PARTICLE REMOVAL
C 0N A SIEVE PLATE DUE T0 FLUX F0RCES AND PARTICLE GR0WTH
C RESULTING IN ENHANCED INERTIAL IMPACTI0N. PLEASE REFER T0
C TEXT F0R EXPLANATI0NS 0F INPUT AND 0UTPUT DATA,C0MPUTATI ONAL
C PR0CEDURES AND PROGRAM APPLICATIONS.
DIMENSION Y<4>
REAL MP,NMP
PRINT,"INPUT?TIN,PIN,TLB,RP,CNP"
INPUT,TIN,PIN,TLB,RP,CNP
GM=7.17E-3
RKL*4.18E+2
RHL=2.4775
RH*2.4775E-2
GMO»GM
DB=0.4
VELB=20.0
VB-0.6
NJ = 5
NI = 13
THT=0 .02
THT=THT/NJ
DZ*0.4
DZ*DZ/NJ
GLDT=TIN-TLB
R0=RP
0CNP = CNP
N=4
YMAX=I .0
YMIN=0.0
DX=0.1
CALL PL0T
C THIS SUBROUTINE, FROM THE GENERAL ELECTRIC MARK II TIME-SHARING
C SYSTEM SUBROUTINE LIBRARY, PLOTS 4 CURVES SIMULTANEOUSLY
C AGAINST ONE INDEPENDENT VARIABLE.
TPS=TIN
DTP«0.0
TLS*TLB
164
-------
APPENDIX 6.A (cont.)
D0 100 I*I«NI
00 80 J=1*NJ
00 30 11 = 1 > 400
TLS=TLB+0.5*(II-1 .0)
PS=EXP(13.64-(5.1E+3/TLS»
DTL=RKL*/<2.0-PIN)-TLS+TLB
*-RHL*CTLS-TIN)/SQRT(TIN)
IF 60 T0 40
30 C0NTINUE
40 00 60 IJ«I»10
TLS=TLS-0.1*(IJ-1 .0)
PS«EXP(I3.64-(5.1E*3/TLS»
DTL«RKL*CPIN-PS)/C2.0-PIN)-TLS+TLB
«-RHL*(TLS-TIN)/SQRT*8.1*PIN
ATIN«TIN+QT/(GM*CPH*THT)
APIN«PIN-DMA*<1 .0-PIN)/CGM*THT)
PA*(0PIN+APIN)/2.0
AKBG«RK/<2.0-PA)
DMB=AKBG*AB**THT*DZ
DMT=DMT*DMP*OMB
TAa(0TIN+ATIN)/2.0
TPS*TA
PPS*EXP(13.64-<5.1E*3/TPS))
IF(PA-PPS.LT.0.0)60 T0 50
165
-------
APPENDIX 6.A (cont.)
AKPGs<2.85E-7*>/RP*(2.0-PPS-PA>
H=>s7.25E-5/RP
TEP*5.1E+3/U3.64-AL0G+5.0E-4
AC=HP/(AKPG*1.OE+4)
TPS=CU .O/O .0*AC/EM))*(TEP-TA))*TA
PPS«EXPO3.64-(5.lE+3/TPS>>
Mps4.2*RP*RP*RP*CNP*VB*DZ
RPD«5.2E-6*CTA**0.75)**US*THT>
CNP«PT*CNP*GM/(GM-(DMP*DMB)/THT)
CPH«7.0*<1 .0-PA) + 8.1*PA
TIN=TIN*QT//(GM*THT)
GM=GM-(OMP*DMB)/THT
80 C0NTINUE
X=0.02*I
YC1)=»
CALL PL0TCX,Y»YMAX»YMIN,N*0*NI>
100 C0NTINUE
PRINT,PIN,TIN,RP,CNP*GM/(0CNP*GM0>
ST0P
END
166
-------
REFERENCES
r H; W« L°Wnie > Jr • A Cost Analysis of
»t?°??r°iS ln the Integ™ted Iron and Steel
*a"elle Memorial Institute. NAPCA Contract
No. PH-22-68-65. P. 259. May 1969.
Calvert, S., J. Goldshmid, D. Leith, and D. Mehta. Scrub-
Calvert, S., J. Goldshmid, D. Leith, and N. Jhaveri.
Feasibility of Flux Force/Condensation Scrubbing for Fine
Particulate Collection. A.P.T. Inc. EPA Contract No.
68-02-0256. NTIS #PB 227 307. October 1973.
Calvert, S. Engineering Design of Fine Particle Scrubbers.
J. Air Pollution Control Association. 24 (10) : 929-933 .
October 1974.
Calvert, S., and N. C. Jhaveri. Flux Force/Condensation
Scrubbing. J. Air Pollution Control Association. 24 (10) :
947-951. October 1974.
Calvert, S. , and S. Yung. Evaluation of Venturi-Rod Scrub-
ber. A.P.T. Inc. EPA Contract No. 68-02-1328, Task No. 5.
August 1974.
Chilton, C. H. Cost Engineering in the Process Industries.
New York, McGraw-Hill. P. 475. 1960.
Goldsmith, P., and F. G. May. Dif fusiophoresis and Thermo-
phoresis in Water Vapor Systems. Aerosol Science. New
York, Academic Press. P. 163-194. 1966.
Handbook of Emissions, Effluents and Control Practices for
Stationary Particulate Pollution Source. Midwest Research
Institute. Report to NAPCA, Contract No. CPA-22-69-104 .
1970.
Hardison, L. C., and C. A. Greathouse. Air Pollution
Control Technology and Costs in Nine Selected Areas.
Industrial Gas Cleaning Institute, Inc. EPA Contract No.
68-02-031. P. 587. September 1972.
Henschen, H. C. Wet vs. Dry Gas Cleaning in the Steel
Industry. J- Air Po11 Control Assoc. 18;338-342. 1968.
167
-------
Hidy, G. M. , and J. R. Brock. The Dynamics of Aerocolloidal
Systems. New York, Pergamon Press. P. 379. 1970.
Klauss, P. R. , P. L. Sieffert , and J. F. Skelly. Costs
and Performance of Control Systems and Control Equipment.
Swindell-Dressier Company. In Appendix C: A Cost Analysis
of Air Pollution Controls in the Integrated Iron and Steel
Industry. Battelle Memorial Institute. NAPCA Contract
No. PH-22-68-65. P. 122. May 1969.
Kotrappa, P., and C. J. Wilkinson. Densities in Relation
to Size of Spherical Aerosols Produced by Nebulization and
Heat Degradation. A.I.H.A. Journal. 33 (7) : 449-453 . July
1972.
Lancaster, B. W. , and W. Strauss. A Study of Steam In-
jection Into Wet Scrubbers.
10(3) :362-369. March 1971.
Ind Eng Chem Fundamentals.
Lapple , C. W. , and H. J. Kamack. Performance of Wet Dust
Scrubbers. Chem Eng Prog. 51 (3) : 110-121 . March 1955.
McAllister, R. A., P. H. McGinnis , and C. A. Plank. Per-
forated Plate Performance. Chemical Engineering Science.
9:25-35. 1958.
Oglesby, Jr., S., and G. B. Nichols. A Manual of Electro-
static Precipitator Technology. Part II. Southern Re-
search Institute. 1970.
Popper, H. Modern Cost Engineering Techniques. New York,
McGraw-Hill. 1970.
Rozen, A. M. , and V. M. Kostin. Collection of Finely Dis-
persed Aerosols in Plate Columns by Condensation Enlargement.
Inter Chem Eng. 7:464-467. July 1967.
Schauer, P. J. Removal of Submicron Aerosol Particles from
Moving Gas Stream. Ind Eng Chem. 43(7): 1532-1538. July
1951.
Semran, K. , and C. L. Witham. Wet Scrubber Liquid Utili
zation. Stanford Research Institute. EPA Contract No.
68-02-1079. P. 115. October 1974.
Taheri , M. , and S. Calvert. Removal of Small Particles from
Air by Foam in a Sieve-Plate Column. J. Air Poll Control
Assoc. 18:240-245. 1968.
168
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Waldmann, L., and K. H. Schmitt. Thermophoresis and Dif-
fusiophoresis o£ Aerosols. Aerosol Science. New York,
Academic Press. P. 137-161. 1966.
Walton, W. M., and A. Woolcock. The Suppression of Airborne
Dust by Water Spray. Inter J Air Poll. 3:129-153. October
1960.
Wheeler, D. M. Fume Control in L. D. Plants. J. Air Poll
Control Assoc. 18 (2) :98-101. January 1968,
16:9.
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-75-018
2.
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
Study of Flux Force/Condensation Scrubbing of Fine
Particles
5. REPORT DATE
August 1975
6. PERFORMING ORGANIZATION CODE
Seymour Calvert, Nikhil C. Jhaveri, and
Timothy Huisking
8. PERFORMING ORGANIZATION REPORT NO
9. PERFORMING ORQANIZATION NAME AND ADDRESS
A.P.T. , Inc.
4901 Morena Boulevard, Suite 402
San Diego, CA 92117
10. PROGRAM ELEMENT NO.
1AB012; ROAP 21ADL-005
11. CONTRACT/GRANT NO.
68-02-1082
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
Final: 10/73 - 6/75
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
is. ABSTRACT
Tlie j^p^f gives results of a laboratory pilot scale evaluation of a multiple
plate, horizontal spray, flux force/condensation (FF/C) scrubber for the removal of
fine particulates . Effects of the significant operational parameters on the scrubber
performance were experimentally studied. Scrubber performance data are presented
in terms of particle penetration as a function of particle size. The experimental
results are compared with predictions from mathematical models. Optimum opera-
tional regions and technical and economic feasibility of FF/C scrubbing are deter-
mined and demonstrated for a single fine particle pollution source. The promising
experimental results clearly indicate that further development of FF/C scrubbing is
warranted.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Air Pollution
Condensing
Scrubbers
Dust
Mathematical Models
Air Pollution Control
Stationary Sources
Flux Force/Condensation
Scrubber
Fine Particulate
Particle Growth
Stephan Flow
13B
07D
07A
11G
12A
18. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
190
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
170
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