oEPA
TRW Charged Droplet
Scrubber Corrosion
Studies
Interagency
Energy/Environment
R&D Program Report
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EPA-600/7-79-017
January 1979
TRW Charged Droplet
Scrubber Corrosion Studies
by
Frederick A. Whitson
TRW. Energy Systems Group
One Space Park
Redondo Beach, California 90278
Contract No. 68-02-2613
Task No. 7
Program Element No. EHE624
EPA Project Officer: Dale L Harmon
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, NC 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
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ABSTRACT
The report primarily presents the results of corrosion
studies undertaken by TRW Energy Management Division to provide
definitive data concerning the corrosive nature of coke oven
waste heat flue gas and its effect on wet type electrostatic
precipitators (ESP) and specifically on the TRW/Charged Droplet
Scrubber (CDS).
The task characterized the chemical composition of the waste
heat flue gases; related these data to corrosion and to the
effects on the electrostatic scrubbing mechanism; evaluated
materials compatibility with the coking process waste heat
environment; and identified candidate agents which may be intro-
duced into the waste heat gas stream to minimize the corrosive
effects. In addition, alternate designs were evaluated for high
voltage isolation and electrical arc sensing and control. The
results of the corrosion studies and concurrent CDS electrical
control and arc sensing system improvements have measurably
increased the available knowledge regarding the corrosion prob-
lems in wet ESP's and improved the potential for more reliable
environmental control equipment.
m
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CONTENTS
Page
Abstract iii
Figures v
Tables viii
Acknowledgement ix
Sections
1. Summary 1
2. Conclusions and Recommendations 6
3. Thermo-Chemical Mapping 8
4. Electrode Geometry 24
5. High Voltage Water Supply Isolation 40
6. Equipment Corrosion 51
7. Flue Gas Stream Corrosives Control 108
8. Electrical Spark Quenching 117
References 128
Appendices
A. Electrical Test Data 129
B. Status of Flue Gas Corrosion Study - Kaiser Steel
Fontana, California 131
C. Wastewater Chemistry 145
iv
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ILLUSTRATIONS
Number
Page
1 TRW Charged Droplet Scrubber Model 070 (140,000 acfm)
coke oven waste heat gas Kaiser Steel Company,
Fontana, CA 2
2 Controlled condensation system setup (modified) 11
3 Gas and liquid sampling positions 13
4 CDS Electrode Geometry 27
5 Case 1, Electrode Geometry, x-y Equipotentials 28
6 Case 1, Electrode Geometry, y-z Equipotentials 30
7 Case 2, Electrode Geometry, x-y Equipotentials 31
8 Case 2, Electrode Geometry, y-x Equipotentials 32
9 Case 3, Electrode Geometry, x-y Equipotentials 33
10 Case 3, Electrode Geometry, y-z Equipotentials 34
11 Case 4, Electrode Geometry, x-y Equipotentials 35
12 Case 4, Electrode Geometry, y-z Equipotentials 36
13 Case 5, Electrode Geometry, x-y Equipotentials 37
14 Case 6, Electrode Geometry, x-y Equipotentials 38
15 Case 6, Electrode Geometry, y-z Equipotentials 39
16 Water Column High Voltage Isolation System 42
17 Air Gap Isolation System 43
18 Isolation Resistor Bank 44
19 Shower Head Nozzle at Zero Potential 45
20 Shower Head Nozzle at -40 KV. . 45
21 Swirl Nozzle at Zero Potential 46
22 Swirl Nozzle at -40 KV 46
23 Water Isolation Tank 49
24 Ceramic Resistor 50
25 Coupon 304-17 (left) and 304-18 (right). Severe
pitting attack with 304-17 showing cracks in
heavily pitted region. Micrograph showing section
through pitted area. Lower casing 59
26 Coupons 316-23 (left) showing mild attack and 316-16
(right) which has extensive pitting attack.
Lower casing 60
27 Coupon 304-24. Pitting and crevice corrosion
Upper casing 61
28 Coupon 316-19. Some pitting attack. Upper casing .... 62
29 Coupon Ni-1. Severe pitting attack has occurred over
entire surface. Lower casing 63
30 Coupon 16-1-2. Extremely severe intergranular attack
with spelling of surface grains. Lower casing 64
31 Coupons 1825-2 (left) and 1825-5 (right). No indications
of corrosive attack. Lower casing 65
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ILLUSTRATIONS (Continued)
Number
Page
32 Coupons Hast. B-l (left) and Hast C-l (right). Some
discoloration of the Hastelloy B specimen. Hastelloy
C-4 not attacked. Lower casing 66
33 Coupon Ni-2. Severe pitting attack. Upper casing 67
34 Coupon 1601-3. Pitting attack on surface. Upper
casing 68
35 Coupons 1617-2 (left) and 1825-1 (right). Surface
roughened (incipient pitting). Upper casing 69
36 Hastelloy C coupon. Severe pitting attack. Upper
casing 70
37 Coupons Ti-1 (top) and T1Pd-l (bottom). Some surface
etching of titanium specimen. Lower casing 71
38 Coupons Ti-12 (upper left), TiPd-3 (lower left) and
Ti-12-3 (upper and lower right). The Ti-12-3 coupon
has pitted. Upper casing 72
39 Coupon Pb-1. Surface film formed which was difficult
to remove. Lower casing 73
40 Coupons 316-4E (left) lower casing and 304-4E (right),
upper casing. EA 919 epoxy coating has failed
exposing substrate 75
41 Coupons S-13RO (top) lower casing and 316-10RO (bottom)
upper casing. Coating failed exposing substrate .... 76
42 Coupons 316-14W (left) lower casing and 216-15W (right)
upper casing. Coating failed exposing substrate .... 77
43 Coupons 316-7PS (left) lower casing and 316-19PS (right)
upper casing. Coating failed in adhesion causing
blistering and delamination 77
44 Coupons 304-3T and Sl-T (upper) lower casing and
216-2T upper casing. Coating failed in adhesion
causing blistering 78
45 Coupons 304-28K (left) and S-24K (upper) lower casing.
Bond failed causing delamination 79
46 Coupons S-18N lower casing. Coating cracked and
delaminated 79
47 Coupon 316-28H lower casing. Surface etched and
cracked 80
48 Steel coated with glass flake filled polyester
(Ceilcote). Surface has been etched by the gases ... 80
49 Steel coated with glass filled vinylesters. Surfaces
have been etched. 4030-1 sample shows coating failure
by chipping off at attachment hole 82
50 Coupon 316-NB. Neoprene elastomer liner shows surface
cracking (checking). Lower casing 83
51 Water spray nozzle couplings from upper casing.
Couplings are coated with polyphenlyene sulfide (PS),
alkyd (RO), vinyl (W) and epoxy (919). The PS coating
was intact (although damaged during the removal opera-
tion). The other coatings failed 84
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ILLUSTRATIONS (Continued)
Number Page
52 Coupons AT382-1 (left) and AT382/05 (right) bisphenol 85
polyesters. Surface checking and cracking
Lower casing
53 Coupon AT-11-1 flame retarded polyester. Surface
etching and checking. Lower casing 86
54 Coupon ASH7240-40 IPA polyester. Surface attack, pits
and cracks. Lower casing 87
55 Coupon ASH7241-29 IPA polyester. Surface etching,
cracking and pitting. Lower casing 88
56 Coupon ASH 197/3-5 polyester. Surface etching, pitting
and crazing. Lower casing 89
57 Coupon ASH 197/3AT-6 polyester. Surface crazing and
pitting. Lower casing 90
58 Coupon ASH 72L-21 flame retarded polyester. Surface
checking, cracking and pitting. Lower casing 91
59 Coupon AT580-1 bisphenol vinyl ester. Surface cracked
and etched. Lower casing 92
60 Coupons ASH800-28 furan (left) and ASH800FR-20 flame
retarded furan. Surface cracking, checking and
pitting. Lower casing 94
61 Coupon HY132 polybutadiene. Some pitting attack at
edge. Lower casing 95
62 Nozzle/grommet joints. Crimped only (left) and
brazed (right) 96
63 Appearance of brazed joint after exposure of 100 hours.
Brazed fillet attacked along second phase. Joint
inboard (toward the header) of crimp unaffected .... 97
64 Electronic corrosion meter (Magna Corporation CK-3) and
type of probe (2143/W40/8020) used for the in-process
corrosion rate measurements 99
65 Boiling point of sulfuric acid in solution with water ... 105
66 Experimental Equipment Arrangement 110
67 Particulate Formation Due to Addition of NHo 113
68 CDS Particulate Throughput for Various Operating Modes
and Different NH3:S02 Molar Ratios (3 m/s (10 fps)
Duct Velocity, 500 ppm S02 Inlet) 115
69 Charged Droplet Scrubber Spark Sensing and Electrical
Power Diagram 118
70 Spark Sensing Coil 121
71 CDS Electrical Power Schematic 122
72 Charged Droplet Scrubber Stage Voltage Sensed Spark
Sensing Circuit 124
73 Oscilloscope Photos of CDS Primary Impedance Addition
Test 126
B-l Location of Corrosion Probe Ports Unit A 144
VI1
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Number
TABLES
Page
1 EQUIPMENT AND SPECIES SEPARATION IN GAS SAMPLING 10
2 CLEANING PROCEDURES 12
3 GAS AND LIQUID SAMPLING POSITION 14
4 SAMPLE RECOVERY 15
5 GAS SAMPLING TRAIN ANALYSIS 16
6 ANALYSIS METHODS 16
7 CDS OPERATION PARAMETERS 17
8 TEMPERATURE PROFILES IN CDS DURING HEAVY AND LIGHT
LOAD CONDITIONS 17
9 GAS PHASE SPECIES CONCENTRATION 19
10 INLET AND CDS DISCHARGE WATER ANALYSIS FROM HEAVY
LOAD CONDITIONS 20
11 ANALYSIS OF SEQUENTIAL CDS DISCHARGE WATER SAMPLES
TAKEN DURING HEAVY LOAD CONDITION 21
12 TIME PHASED CDS WATER SAMPLE LOG 23
13 ELECTRODE GEOMETRY PARAMETERS 26
14 CONDITION OF MATERIAL TEST COUPONS - LOWER CASING 55
15 CONDITION OF MATERIAL TEST COUPONS - UPPER CASING
(HOOD) 58
16 WEIGHT CHANGE OF METALLIC TEST COUPONS 98
17 CORROSOMETER DATA 98
18 WALL TEMPERATURES OF NORTH CDS UNIT 100
19 SUMMARY OF MATERIALS PERFORMANCE 101
20 CDS REMOVAL EFFICIENCY FOR GAS PHASE S02 (32 KV
ELECTRODE VOLTAGE 3 m/s (10 fps) GAS FLOW VELOCITY). . . 112
21 S02 THROUGHPUT COMPARISON FOR WET AND DRY COLLECTOR
PLATES (CDS TURNED OFF, 3 m/s (10 fps) DUCT FLOW
VELOCITY) 112
22 CDS PRIMARY IMPEDANCE ADDITION TEST TABLE 125
A-l KAISER CDS GAS TEST NON-UPSET CONDITION 129
A-2 KAISER CDS GAS TEST UPSET CONDITION 130
B-l TABULATION OF MATERIALS AND COATINGS SELECTED
FOR TESTING 133
B-2 LOCATION OF TEST COUPONS IN UPPER CASING (HOOD) 136
B-3 LOCATION OF TEST COUPONS IN LOWER CASING 137
vi i i
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ACKNOWLEDGEMENT
We would like to acknowledge the effective efforts of
Maurice Bianchi and Lou Resales of the Materials Division,
the principal investigators for the Equipment Corrosion
Study.
In a more somber vein, we would like to note the passing
of Walter Krieve. With his death we lost a great human being
and he will be sorely missed. Walt was involved in the birth
of the CDS and his genius was the driving force behind much
of the development. As principal investigator for the High
Voltage Water Supply Isolation, Electrode Geometry Study and
Flue Gas Stream Corrosive Control his increasing efforts in
the face of personal adversity were particularly noteworthy.
Without his skill, expertise and professionalism this work
could not have been accomplished. The technical assistance
for all of Walt's work was provided for by Andy Seaton.
We would also like to acknowledge Marshal Huberman,
Ray Maddalone and Joe Sauer for their contributions.
IX
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SECTION I
SUMMARY
BACKGROUND
The Environmental Protection Agency funded a demonstration program of the
TRW/Charged Droplet Scrubber (CDS) on a coke oven waste heat gas emissions
control application. As a result of this, a full scale CDS was subsequently
installed at the coke oven facility of Kaiser Steel Company, Fontana,
California, Figure 1.
After the initial few hundred hours of operation a definite degradation
in the CDS collection efficiency was noted. A preliminary inspection of the
equipment revealed that the lower efficiency was due to a lower electrode
operating voltage resulting from corrosion-caused mechanical failures within
the CDS system. A more detailed inspection revealed that the most severe
corrosion took place within a localized area of the CDS electrical collection
section. This area proved to be directly downstream of a failed element of
the gas distribution assembly. The resulting local overload produced
excessive electrical arcing and thereby compounded the chemical corrosion
with electrical erosion.
Some preliminary analysis of the CDS supply water indicated that the
chloride content had increased more than tenfold (from 20 ppm to more than
200 ppm) over the high average anticipated, based on customer supplied analy-
sis. This would account for the pit-type corrosion of the 316SS, but did not
provide sufficient data to explain the generalized deterioration of the equip-
ment internal components and outer casing.
Because the understanding of these problems is essential to the pollution
control industry in general and for coke oven emission control in particular,
the Environmental Protection Agency was asked and agreed to sponsor a program
for an investigation of the problem.
PROGRAM SUMMARY
An investigative program was conducted during the time period of August
1977 through February 1978. The program was primarily directed at determin-
ing the types and causes of corrosion experienced in the TRW/Charged Droplet
Scrubber installed on a coke oven application located at the Kaiser Steel
Company plant.
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Figure 1. TRW Charged Droplet Scrubber Model 070 (140,000 acfm) Coke Oven Waste Heat Gas
Kaiser Steel Company, Fontana, California
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The corrosion studies program was undertaken to provide definitive data
concerning the corrosive nature of coke oven waste heat flue gas and the
effect of this gas on a wet type electrostatic precipltator and specifically
on a wet ESP known as the Charged Droplet Scrubber.
The task was divided into the following Interrelated Investigations:
1) Thermochemlcal Mapping
2) Electrode Geometry
3) High Voltage Water Supply Isolation
4) Equipment Corrosion
5) Flue Gas Stream Corrosive Control
6) Electrical Spark Quenching
It was determined that the coke oven waste heat gases contained a wide
range of compounds as expected. Those present 1n greatest quantity are C,
S02, H2S, 02, NOX, CH3, Ho, HCN, S, CO, C02, N2. Water reacts with these com-
pounds in the gas stream to form sulfuric acid and, to a lesser extent, car-
bonic and nitric acids. Since the temperature ranges from a high of 149*C
at the inlet duct to a low of 45°C within the CDS, sulfuric acid condenses on
the cooler surfaces and becomes more and more concentrated as the lower vapor
pressure water boils off in areas that are not frequently flushed with water.
This combined with the significantly higher chloride content of the water was
the primary causes of the generalized corrosion of 316-type stainless steel
casing. The pit-type corrosion was primarily due to the high chloride content
alone.
Material test coupons were installed throughout the gas cleaning system
so as to be exposed to the complete spectrum of environmental conditions that
exist within the equipment. Various coatings where also applied in the same
locations. None of the coatings selected were able to withstand the hostile
environment. Of the metallic sample coupons tested, commercially pure
titanium and Incoloy 825 performed the best. Chemical lead samples performed
satisfactorily 1n the lower casing. The resistance to pitting and crevice
corrosion seems to roughly follow the molybdenum content. Of the fiberglass
reinforced plastic panels tested, only the polybutadlene showed acceptable
resistance.
As expected, those surfaces where deposits could accumulate experienced
the most severe corrosion. The process was accelerated on those surfaces
because the deposits would prevent the renewal of the protective oxide layer
which normally protects the base metal. To minimize this occurrence, the
equipment wash system was redesigned to flush all surfaces where deposits
could accumulate and the frequency and duration of the wash cycle was
Increased.
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In addition to the materials test program, an experiment was conducted
to determine 1f additives to the gas stream could Inhibit corrosion without
adversely affecting the efficiency. Analysis of thermo-chemlcal mapping and
results of the materials test performed, Identified gaseous S02 as the compound
causing the most severe corrosion problem. With this 1n mind, the candidate
additive chosen was NH3. The NHs does react with the gaseous SO? in such a
way as to form a participate which then can be scrubbed by the CDS. Limited
testing of a single-stage test unit Indicates that a four-stage CDS unit would
be 99 percent efficient 1n removing the resultant partlculate.
As a result of the corrosion which took place on the high voltage
electrodes, arcing between the electrode and collector plates occurred at a
lower than normal voltage because of the change 1n geometry. The basic elec-
trode geometry has the desired electric field distribution characteristics
but, 1f distorted to the degree experienced here, a significant degradation 1n
performance can occur.
An analytical model of the electrode was generated and a parametric
analysis performed. The results indicated that the collection efficiency may
be increased by increasing the number of nozzles, but a basic geometry change
was not indicated for increasing arc threshold (operating voltage).
One of the two CDS units which comprises the control system was Isolated
from the gas stream. The other was retrofitted with the design changes
indicated by the analysis and Included a gas distribution system design which
would preclude a similar failure. The basic materials remained 316SS, but a
locking gasket made of silicon rubber was replaced with Viton rubber. In
addition, structural members were added to further support the gas distri-
bution assembly. The existing wash system was expanded and additional wash
assemblies were installed to ensure coverage of all areas that may be subject
to deposit accumulation.
During the remaining time permitted under the program, the new wash
system was proven capable of preventing deposit accumulation. The modified
gas distribution assembly significantly improved the gas distribution through-
out the collection system and in doing so Improved the overall performance
with respect to spark distribution and therefore electrode life expectancy.
Since the energy as well as the frequency of the sparking Influences the
electrode life, it was also appropriate at this time to review the power
control system design.
Standard electrostatic precipitator-type power supplies as 1s used in the
CDS design has a high ripple characteristic. Filter capacitors are used to
reduce the ripple to an acceptable level (25 percent) necessary for the Charged
Droplet Scrubber applications. When an arc occurred, these capacitors dis-
charged all the stored energy Into the spark. These high energy arcs are
damaging to the electrode nozzles as the result of extremely high localized
temperatures. A series of tests were performed to assess the effects of remov-
ing the filter capacitors. It was demonstrated that the equipment can be
operated without the filter capacitors with few minor changes to the control
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system, but at the cost of reducing collective efficiency. However, an alter-
nate method for controlling the ripple amplitude has the potential for Increas-
ing efficiency above the original level. It was also determined that the
antenna-Uke coll used for spark sensing could not operate efficiently for
extended periods of time and was subject to spurious Input signals. An alter-
nate sensing system was designed, developed and tested. It detects sparking
by sensing abrupt voltage changes through a voltage divider located outside
the hostile environment of the collecting section.
Another area which did not Influence corrosion, but has the potential for
affecting the efficient operation of the unit, 1s the changing conductivity of
the water supplied to the electrodes and Its effect on the high voltage
Isolation. Initially, Isolation was provided by the resistance of the water
along a length of non-conducting pipe. As water conductivity changed, so did
the value of this resistance and caused greater leakage of current to ground.
A new method of isolation was needed. A design was formulated and tested
Involving the use of an air gap as the Isolation mechanism. The water at
ground potential flows through a specially designed spray nozzle which sepa-
rates the stream into discrete droplets providing discontinuity. This stream
1s collected 1n a container insulated from ground and 1s connected to the power
supply. The container acts as a reservoir and carries the electrical charge
required for atomlzation at the electrode as well. The design has operated
with a charge as high as 50 KV and water conductivity of up 60,000 ymho/cm.
The results of the CDS corrosion studies and the concurrent CDS Redevelop-
ment Program have measurably Increased the available knowledge regarding the
corrosion problems 1n the coke oven waste heat gas environment and demonstrated
the need to fully characterize the gas constituents prior to designing a con-
trol system for any emissions problem.
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SECTION 2
CONCLUSIONS AND RECOMMENDATIONS
Detailed conclusions and recomnendatlons are presented 1n the sections
which address specific areas of Investigation. However, they are summarized
here for convenience.
CONCLUSIONS
1) The tenfold Increase of the CDS supply water chloride content was a
major contributor to the pitting corrosion of the CDS electrodes and
casing.
2) Generalized equipment corrosion 1n similar systems can be minimized
1f adequate flushing systems for the prevention of deposit accumu-
lation are Installed.
3) Greater corrosion resistance in the coke oven gas environment can be
attained by the use of metals having a higher molybdenum content.
4) The corroslveness of the coke oven waste heat gas stream can be
reduced by the injection of additives such as NH3.
5) The CDS has the potential of becoming an efficient S02 scrubber.
6) CDS electrode life can be significantly Increased by the deletion of
filter and R-C circuit capacitors with a small sacrifice in
performance.
7) The basic electrode geometry utilized in the CDS has the desired
electrical field distribution characteristics.
8) The CDS systems dependence on a constant water electrical conduc-
tivity can be voided by the Incorporation of A1r Gap electrical
Isolation system.
9) The CDS is capable of controlling the emissions from a coke oven
waste gas system.
RECOMMENDATIONS
1) Further characterization of coke oven waste gases should be
performed and the results correlated with the process equipment
and coal types.
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2) Long duration materials compatibility tests should be performed in
the coke oven waste gas environment while simulating the conditions
which might be anticipated 1n the various types of emission control
equipment.
3) Further Investigate the options of additives for corrosion control
1n the coke oven environment.
4) Alternate ripple control methods should be investigated for the
Charged Droplet Scrubber application. The potential benefit would
be an Increase 1n collection efficiency as the result of a higher
average voltage and an increase in equipment life.
5) Individual power sets should be provided for each electrode stage
for the purpose of improving system performance and reliability.
6) Replace the present pickup coil-type spark detection system with a
design which directly senses abrupt voltage changes (sparks) through
a voltage divider.
7) Complete the development of the Air Gap high voltage isolation
system.
8) Complete the overall CDS development.
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SECTION 3
THERMO-CHEMICAL MAPPING
INTRODUCTION
Coking oven waste heat gas constituent measurements were conducted at
the Kaiser coke plant facility during heavy and light-load conditions. These '
measurements consisted of a simultaneous 3-po1nt gas/particle sampling effort.
Concurrent with these gas phase samples, composite liquid samples were taken
from the CDS waste water discharge and the outlet opacity was monitored.
The goal of the test program for this subtask was to provide thermo-
chemical mapping based on the key locations in the CDS:
• Pre-cooler Inlet (just upstream)
t CDS inlet, 24 m (3 ft) from CDS
• CDS exit, 15.2 m (50 ft) downstream
In the latter two cases significant modification of the chemical composi-
tion of the gas stream could occur due to the Introduction of water, reduction
of temperature, removal of particulate matter, or any combination of the three.
The tests were conducted under the two different conditions experienced during
normal operation: Heavy load (30 percent opacity which occurs during the oven
loading cycle) and light load (after the ovens reach steady state temperature
and opacity, 10 percent). During these two conditions, species such as S02,
H2S04/S03, HC1, and HF were measured in the gas phase. Other species such as
Ni+2, Cr+3, Fe+3, and Fe+2 were measured in the particulate matter collected
by the sampling trains. The sampling train also had a thermocouple for the
measurement of temperature.
In addition to these gas phase results, water samples from the CDS dis-
charge were taken during the above tests. The water was analyzed for SOl
SOj, Cl", F", Cu+2, Fe (total), Fe+2, Ni, hardness, conductivity, pH and
Chemical Oxygen Demand (COD). This data would be compared to gas phase data
to attempt to find any sign of CDS corrosion.
CONCLUSIONS AND RECOMMENDATIONS
The Kaiser CDS facility was thermo-chemlcally mapped by sampling at three
key locations (Inlet CDS, exit pre-cooler and exit of the CDS).
8
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The results showed that:
• Temperature profiles during heavy and light-load conditions were
quite similar
t Outlet gas temperatures were at or slightly above 100°C
• Sulfur dioxide concentrations at the three locations did not vary
significantly showing essentially no removal of S02 with the CDS
operating conditions used during the tests
• Both S02 and $63 concentrations were higher during the light load
tests
t Removal efficiencies for H2S04 varied from 72 percent to 100 percent
during the light load and heavy load tests respectively
• No significant amounts of HF was found in either test, but HC1 was
23 percent by weight of the H2S04 concentration during the heavy
load tests
Based on these findings it is recommended that the current wash cycle be
reprogrammed to prevent interruption of the cycle by upset conditions. With-
out this feature H2$04 would tend to accumulate in the CDS and cause signifi-
cant corrosion problems.
TEST PROCEDURES FOR CDS FACILITY
The equipment, the preparation, and the procedures necessary to perform a
simultaneous 3 point gas/particle sampling effort at the CDS emission control
system located at Kaiser Steel Company's Battery "A" coke ovens are dis-
cussed below. The location for collecting composite In liquid samples as well
as the temperature and pressure monitoring locations are also discussed.
Equipment
The particle/gas sampling train used for this test program is the Control-
led Condensation System (CCS) (Reference 1). CCS is designed to measure the
vapor phase concentration of SOa as H2S04 in controlled or uncontrolled flue
gas streams. This method is specifically designed to operate at temperatures
up to 250°C (500°F) with up to 3000 ppm S02, 8-16 percent H20, and up to
9 g/m3 (4 gr/cf) of partlculate matter.
By using a modified Graham condenser, the gas is cooled to the acid dew
point at which the $03 (H2S04 vapor) condenses. The temperature of the gas
is kept above the water dew point to prevent an Interference from S02 removed
by condensing water while a heated quartz filter system removes partlculate
matter. The condensed acid is then titrated with 0.02 N NaOH using Bromo-
phenol Blue as the Indicator.
The CCS, which was used for gas sampling, consists of a heated quartz
probe, quartz filter holder, Tissuequartz filter, controlled condensation
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coll and five implngers. For the gas sampling measurements the 1mp1ngers were
filled with 3 percent H202 (one) and 3 percent high purity Na2C03 (two) and
DHerite (one) (Figure 2). The predicted distribution of the species collected
1n the train 1s shown 1n Table 1. The fabrication of this equipment 1s
described 1n detail 1n Reference 1.
TABLE 1. EQUIPMENT AND SPECIES SEPARATION IN GAS SAMPLING
SAMPLE TRAIN COMPONENT
COLLECTED SAMPLE
Probe
Filter
Controlled Condensation Coll
3% H202Impinger (1)
3% Na2C03 (high purity) (2)
Partlculate
Particulate
H2»4
S02 (HC1, HF, HCN)
H2S, HC1, HF, HCN
The liquid sampling was conducted using a pump, Teflon tubing and a
gallon gas container. During the tests a sample was taken every 5 minutes
(- 500 ml) Into a 4* container. These samples were either apportioned Into
a U pre-cleaned polypropylene container for Inorganic analysis or Into a
glass container with a Teflon top for organic analysis.
Preparation
The glassware and plastic containers used during this sampling test were
pre-cleaned to avoid sample contamination. The procedures used for this clean-
Ing are described in Table 2. High purity reagents (Baker Utrex or equiva-
lent) and water (ASTM type I or better, Reference 2) were used.
Sampling Procedures
The goal of these tests was to provide a chemical map of the CDS emission
control system. The three gas phase sampling trains for simultaneous sampling
were located at positions which would have the greatest change 1n gas compo-
sitions and temperature:
• CDS Inlet
• Pre-cooler exit
t CDS exit
To complement these gas sampling positions, samples of the Inlet water
and CDS discharge water were taken. Figure 3 and Table 3 show and describe
10
-------
RUBBER VACUUM HOSE
ADAPTER FOR CONNECTING HOSE
TCWELL
STACK
VACUUM
GAUGE
ASBESTOS CLOTH
INSULATION
GLAS&COL
HEATING
MANTLE
QUARTZ
FILTER
HOLDER
RECIRCULATOR
THERMOMETER
DRY TEST
METER
THREE WAY VALVE
VALVE
Figure 2. Controlled condensation system setup (modified).
-------
TABLE 2. CLEANING PROCEDURES
CLEANING PROCEDURES (ORDER APPLIED LEFT TO RIGHT)
COMPONENT
Nylon Brush
Probe Liner
Cyclone
Filter
Housing
Implngers
Connecting
Glassware
Control 1 ed
Condensation
Coll
Filter
Tissuequartz
Plastic
Storage
Bottles
MUFFLE
(288°C)
4 hrs
Brush
X
X
Optional
Optional
15% HN03
3 hrs
Rinse/Brush
Rinse/Brush
Rinse
Rinse
Rinse
3 hrs/R1nse
3 hrs
H20
Rinse
Rinse
Rinse
Rinse
Rinse
Rinse
Rinse
Rinse
ACETONE
Rinse
Rinse
Rinse
Rinse
Rinse
Rinse
Rinse
METHYLENE
CHLORIDE
Rinse
Rinse
Rinse
Rinse
Rinse
Rinse
Rinse
AIR
DRY
X
X
X
X
X
X
X
X
REMARKS
Inspect for corrosion,
degradation and
bristle shedding; dis-
card 1f any found
All material must be
removed via brush
and rinsing
All material must be
removed via brush
and rinsing
Back flush to remove
any Impacted material
1n the front/side
HN03 soak not neces-
sary 1f no parti cu-
late 1n coll - simply
rinse
Field blank samples
will be analyzed 1n
parallel with actual
sampl es
Linear polyethylene or
polypropylene
ro
-------
GAS
OUTPUT
Figure 3. Gas and liquid sampling positions.
-------
TABLE 3. GAS AND LIQUID SAMPLING POSITION
POSITION
MEASUREMENTS
CONDITIONS
1. Inlet to precooler
2. Inlet to CDS
3. Exit CDS
4. CDS spray water
5. CDS discharge
Gas/particulate
and temperature
Gas/particulate
Gas/particulate
and temperature
Liquid
Liquid
Just prior to precooler
230 - 260°C
Just prior to CDS in
transform stage
120 - 132°C
After fan, approximately
50 ft downstream of the
CDS 79 - 93°C
Domestic water used in
the discharge line
Leading to the sump
the locations and lists the samples and the measurements. Engineering data such
as gas flow rates, water inputs, opacity measurements and process information
were also collected for later correlation with the sample analysis. The test
conditions were arranged so that a sample was taken during light load and heavy
load conditions. During the light load condition, a nominal run time of one
hour was used. Sampling during the heavy load period continued until the
opacity was below 30 percent (45 minutes). Since all of the pre-cooler water
was vaporized there is no quench water sample.
All liquid sample containers were completely filled and capped to exclude
air. To supplement these water samples, additional U samples of water for COD
analysis were taken. These water samples were stored in pre-cleaned (follow-
ing impinger cleaning procedure) amber glass bottles with Teflon lined tops.
Both water samples were returned to the laboratory for immediate analysis.
The CDS was operated as described in Reference 1 except for the following
changes:
0 The filter was saved
• The probe rinse was saved
• 100 ml of 3 percent fyfy and 3 percent NagCOs was used
• High purity reagents were used
The list of the samples recovered is presented in Table 4.
14
-------
TABLE 4. SAMPLE RECOVERY
RECOVERY PROCEDURE
STORAGE*
Probe and
ProbeURinse
Filter
Controlled
H202 Implngers
Probe shaken or tapped to remove loose
particles then brushed. Remaining participate
matter rinsed in container with 15%
followed by H20
Remove, fold in half and place in sealed jar
Remove coll from train, Invert over container
and rinse repeatedly with high purity
Plastic
Rinse all condensate in preceding lines into
implnger with high purity H20. Rinse Impinger
with high purity ^0 and save condensate and
rinses
Rinse all condensate 1n lines Into next Impinger,
Save all impingers. Rinse with
Plastic
Plastic
Plastic
Blanks
Place samples of high purity H20, \\2$2* Na2C03
and HN03 in separate containers
Plastic
Plastic
Plastic refers to linear polyethylene or polypropylene precleaned containers
(see preparation).
ANALYSIS OF CDS SAMPLES
The material from the Individual train components was recovered and
returned for analysis. Table 5 lists the train component and the analysis per-
formed. The water samples obtained from the test were analyzed for all of the
species listed 1n Table 5 with the addition of hardness (as CaCOs), conductivity,
pH, and COD.
All required samples were filtered through 0.45 micron Mllllpore filters.
Methods used were those described 1n Federal Register, 41, No. 232, 1976, and
are listed in Table 6.
15
-------
TABLE 5. GAS SAMPLING TRAIN ANALYSIS
SPECIES
Cr(T)
Fe(T)
Fe
N1
CL-
F-
soj2-
S0§2
H+
PARTI CULATE
PROBE RINSE
X
X
X
X
X
X
FILTER
X
X
X
X
X
X
X
X
CCC*
X
H202
IMPINGE RS
X
X
X
Na2COs
IMPINGE RS
X
X
X
CCC = Control Condensation Coil
TABLE 6. ANALYSIS METHODS
SPECIES
ANALYSIS PROCEDURE
Nickel
Chromium
Copper
Iron (Total)
Chlorides
Fluoride
Cyanide
Sulflte
Sulfate
Sulflde
pH
Hardness
Specific
Conduct"! v1 ty
Iron II
Atomic absorption
Atomic absorption
Atomic absorption
Atomic absorption
T1trat1on with mercuric nitrate
Ion selective electrode (no distillation step)
Pyr1d1ne-Barbitur1c add (no distillation step)
T1tr1metr1c - Iodine
Turb1d1metr1c
Photometric - methylene blue
Electrometrlc
Sum of Ca, Mg and Fe by AAS
Wheatstone Bridge conductImetry
Photometric - 1, 10 phenanthroline
16
-------
RESULTS AND DISCUSSION
The gas and liquid sampling program was conducted during heavy load and
light load conditions on separate days. The CDS operating parameters are shown
1n Table 7. A log of electrical parameters recorded during the tests are
presented 1n Appendix A.
The CCS trains were equipped with thermocouples to measure the waste gas
temperature at the three positions sampled. The temperature profile for both
cases are very similar, as seen 1n Table 8. This data shows that the quench
water 1s completely evaporated and that no free liquid 1s available to scrub
S02 or S03 1n the quench area.
TABLE 7. CDS OPERATION PARAMETERS
VARIABLE
Percentage Opacity. %
Inlet Gas Flow (dsm /min)
(dscfm)
o
Outlet Gas Flow (dsm /min)
(dscfm)
Inlet % H20
Outlet % H20
Quench Water Flow (i/mln)
(gpm)
Electrode ^0 Flow (£/m1n)
(gpm)
Average Stage Electrode
Voltage (KV)
CONDITION
LIGHT LOAD
9.3 + 4
787-827
27,800-29,200
932-997
32,900-35,200
14
14
38-57
10-15
19
5
32.1 +2
HEAVY LOAD
33 + 15
787-827
27,800-29,200
932-997
32,900-35,000
9
14
38-57
10-15
19
5
30.7 + 1.8
TABLE 8. TEMPERATURE PROFILES IN CDS DURING
HEAVY AND LIGHT LOAD CONDITIONS
POSITION
Inlet to Precooler
Inlet to CDS
Exit CDS
TEMPERATURE. °C
LIGHT LOAD
237 + 5
158
104 + 1
HEAVY LOAD
232 + 2
182 + 5
97 + 2
17
-------
Acid Gas and Participate Concentrations In the CDS
While the CCS 1s primarily a HgSt^ sampling system, the train as set up
at Kaiser was capable of collecting participate material, H2S04, S02, HC1 and
HF. The results for species monitored In the gas phase are tabulated 1n Table 9
for the three positions monitored in the CDS.
The most striking feature of the gas phase analysis results In lack of
SOg scrubbing by the CDS. Previous CDS tests at Kaiser indicated that a 13 per-
cent S02 removal per stage was possible. However, operating conditions during
the latest series of tests were different than the original S02 removal studies.
One CDS unit was isolated from the gas stream and the total gas volume was
passed through the remaining CDS unit. The resulting liquid to gas ratio was
one half that of the original tests. Finally, the spark rate during the
original S02 removal studies was approximately twice as high. The end result
of these changes is to decrease the gas residence time, reduce the 11 quid/ gas
(1/g) ratio and decrease the ozone formation. The residence time and 1/g ratio
directly affect the S02 scrubbing efficiency of any scrubber system and appear
in the CDS to be very Important factors in SOg removal. The lower spark rate
produces less ozone and probably reduces the §03 formation. Converting S02 to
S03 should increase the S02 removal by reducing the apparent amount of S02 in
the gas phase and actually permitting the CDS to remove $03 as a liquid aerosol
of H2S04. The latter point seems to be proven by the H2S04 data obtained in
the light load condition where the H2S04 value steadily decreased across the
CDS. The CDS system (quench water + spray nozzles) appears capable of removing
72 percent of the ^$64 Introduced into the system of which 60 percent 1s
removed by the spray nozzles.
The data for the upset condition 1s not as clear-cut, since the SOl and H*
titration of the coll rinse did not agree. It appears that another acidic
species was condensed in the coil along with f^SCh. Visual observations In the
field Indicated that coll rinse to be discolored instead of clear as In the
light load condition. The plume during the upset condition was black with coal
and hydrocarbon aerosol by-products.
The filter system, which 1s heated to 200°C, probably allowed organic
material to pass into the coil. While there was not enough solution for further
confirmatory analysis, 1t was possible that an organic acid or phenol caused a
positive Interference with the H+ analysis.
Using the S0$ tltration values as the true ^$04 concentration, the CDS was
100 percent effective 1n removing H2S04 during the heavy load condition. The
reason for this improved efficiency was probably due to the presence of the
large quantity of particles. The H2S04 in the high humidity of the CDS probably
condensed on the solid particles and grew 1n size because of the hydroscoplc
nature of H2S04. These larger l^SO* liquid aerosols were more easily removed
by the CDS.
The results of these tests show that the H2S04 concentrations during the
light load mode are higher than the upset mode. This finding indicated that to
minimize corrosion a wash cycle must be maintained during the long period of
18
-------
TABLE 9. GAS PHASE SPECIES CONCENTRATION
CONDITION/
DATE
Heavy Load
11/8/77
Light Load
11/9/77
POSITION/
GAS VOLUME
Inlet
Pre-Cooler
Exit
Inlet
Pre-Cooler
Exit
SPECIES CONCENTRATION (mg/dsm3)
Cr
0
0
0
0
0
0
N1
0
0
0.8
0
0
0
Fe(II)
0
0
0
0
0
0
.Fe(T)
0
9.6
1.1
0
0.2
0
Cl"
13.2
1.2
7.5
2.3
1.6
1.9
F"
0.41
0.49
0.50
0.23
0.34
0.31
S02
441
(154 ppm)
466
(163 ppm)
530
(186 ppm)
600
(210 ppm)
569
(199 ppm)
620
(217 ppm)
H2S04
S04
57
(13 ppm)
28
(6.4 ppm)
0
81.4
(18.5 ppm)
57.1
(13.1 ppm)
22.6
(5.2 ppm)
H+
51
(12 ppm)
76
(17 ppm)
28
(6.4 ppm)
79.8
(18.2 ppm)
58.4
(13.3 ppm)
21.3
(4.9 ppm)
Remarks
2.9 mg/dsm3
as SOa on
filter
4.3 mg/dsm3
as S04 on
filter
=3
-------
light load (I.e., non-operation of the CDS). Simply leaving the CDS in the
down status will allow significant quantities (3.5 kg/hr) of H2S04 to accumu-
late in the CDS.
The rest of the results from the gas phase test indicate no unusual
amounts of HC1 or HF. While there appears to be some Fe present in the
particulate matter, there is no evidence of N1 or Cr which would indicate
gross erosion of the 316SS in the CDS.
Liquid Sample Test Results
The analysis of the water samples taken during gas sampling are shown in
Tables 10 and 11. The amount of Fe, Cr and Ni found in the discharge water
roughly corresponds to the ratio of Ni and Cr found in 316SS, and might be
evidence of corrosion in the CDS. It is also possible that the acidic (pH 2.5)
sump water simply extracted the particulate matter collected by the CDS. Since
the particulate matter collected on the filter was only water extracted, this
could explain the lack of finding Fe in the inlet particulate sample.
Prior to this test series, a series of time sequenced water samples were
taken from the CDS water discharge during a heavy load condition. The results
TABLE 10. INLET AND CDS DISCHARGE WATER ANALYSIS FROM HEAVY LOAD CONDITIONS
SPECIES
Chromi urn
Iron (Total)
Iron (II)
Nickel
Chloride
Fluoride
Sulfate (Turbidimetric)
Sulfite
H+ (as H2S02)
Hardness (as CaC03)
Conductivity
pH
COD
Sulfate (by BaC104 Titration)
CDS SUPPLY WATER
<0.03 mg/1
<0.03 mg/1
<0.05 mg/1
<0.03 mg/1
7.5 mg/1
0.2 mg/1
<1 mg/1
<1 mg/1
<1 mg/1
73 mg/1
210 mnhos/cm
8.02 units
—
--
CDS DISCHARGED
0.50 mg/1
3.33 mg/1
1.15 mg/1
0.37 mg/1
21.7 mg/1
0.5 mg/1
364 mg/1
<1 mg/1
245 mg/1
96.9 mg/1
2000 ymhos/cm
2.46 units
21 mg/1
376.2
20
-------
TABLE 11. ANALYSIS OF SEQUENTIAL CDS DISCHARGE WATER SAMPLES TAKEN DURING HEAVY LOAD CONDITION
SAMPLE NUMBER
ANALYSIS
Nickel
ChroaluB
Copper
Iron II
Iron (Total)
Chloride
Fluoride
Cyanide
SuUlte
Sulfate
Sulflde
pH (units)
Hardness (as CaCo3)
Specific Conductivity
9 2S°C
(MIcroBhos/ca)
11
<0.03
<0.03
<0.02
<0.04
-------
of the analysis of these samples are tabulated In Table 11 and explained 1n
Table 12. The values found are similar to the composite sample values
taken on November 8 and 9, 1978. The time sequence samples show a relatively
even concentration of the species measured with no large spike from any of
the coke oven operational processes. The only anomaly associated with this
data was the apparent loss of chloride from the discharge water compared to
the inlet water. This anomaly could not be explained by re-entra1nment of Cl"
in_the form of liquid aerosols since there was no significant Increase In the
Cl" content of the gas stream.
22
-------
TABLE 12. TIME PHASED CDS WATER SAMPLE LOG
SAMPLE NO.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
TIME*
2:20
3:10
3:15
3:20
3:23
3:25
3:27
3:29
3:31
3:33
3:34
3:37
3:57
3:43
3:43
3:49
3:53
3:56
4:00
LOCATION
H20 Input
CDS Disch.
CDS Disch.
CDS Disch.
CDS Disch.
CDS Disch.
CDS Disch.
CDS Disch.
CDS Disch.
CDS Disch.
CDS Disch.
CDS Disch.
Domestic
Water
CDS Disch.
CDS Disch.
CDS Disch.
CDS Disch.
CDS Disch.
CDS Disch.
PROCESS CONDITIONS
Domestic water
Battery in steady state ~ light load — before pushing begins
First oven pushed — started sample at ram retraction plus one
Oven pushed but not yet charged
Start of charging operation
Charging in process
Charging completed, sltght stack emission - beginning of heavy
Heavy load
Heavy load
Start of pushing operation on second oven
One minute after start of push
One minute after Ram retracted
Charging vent closed on second oven pushed
Heavy load continues — 5 minute sample time (3:43 start, 3:48
High spark rate in unit - heavy load
One minute after ram retracted on third oven pushed
Heavy load continues
minute
load
complete)
End of battery activity -- stack looks good - slight steam plume
INS
*30 Second time period to pull one sample with vacuum pump
-------
SECTION 4
ELECTRODE GEOMETRY
INTRODUCTION
The electric field at the tip of the spray tube influences two significant
factors; 1) the charge to mass ratio of the sprayed droplets and 2) and the
acceleration of the droplets away from the tip. For a given geometry the
applied voltage determines not only the field at the spray tube tip but also
the field strength within the remainder of the sweep volume.
In normal operation the CDS voltage is set at the highest value compatible
with a permissible arc rate. Arcing frequently initiates at the tip of the
spray tube since, because of the relatively small tube diameter, this is the
region of highest field intensity. However, the onset of corona produces a
conducting plasma around the tip which enlarges the effective tip radius and
decreases the field strength at the tip. When this occurs arcing can initi-
ate in other regions, as for example, at the wall of the electrode tube.
The phenomenon is further complicated by the presence of water drops on the
electrode and the influence of space charge within the scrubber.
The objective of the task described in this section was to generate
analytic computer plots of the field distribution for various geometries in
order to better understand the influence of geometry on the field distri-
bution and hopefully to indicate the direction for future design improvements.
CONCLUSIONS AND RECOMMENDATIONS
The basic electrode geometry, as represented by Cases 1 and 3 of Table 13,
has the desired electric field distribution characteristics. Some optimiza-
tion may be afforded by further parametric investigation of needle length
variation. The electric field plots also suggest that reduction in needle
spacing may yield a more efficient electrode by introducing more spray tubes
per unit length of electrode tube, without appreciable altering the strong
potential gradient towards the collector plates.
The predicted effects are not dramatic. A parametric experimental study
will be required to determine the magnitude of the improvements to be attained.
Calculations for the full space charge case should also be performed. How-
ever, in view of the small effects predicted by the Laplace solutions it is
anticipated no dramatic geometric dependence will be prediced by the Poisson
solutions for the scale of geometric variations that have been studied.
24
-------
ANALYTICAL APPROACH
Analytical models of a series of two dimensional representations of the
CDS electrode geometry were programmed for parametric analysis. The geometry
used is illustrated in Figure 4. The high voltage electrode is centered
between two parallel, grounded collector plates at a distance 2b apart.
The electrode tube has a radius of a', and holds a series of spray tubes of
radius a each, spaced at distance c from one another. The spray tubes pro-
trude a distance a, from the centerline of the electrode tube.
Zero space charge field distributions were calculated as functions of
the various geometric parameters. This was done by obtaining computer field
plots and solutions of Laplace's equation for the geometries of interest.
Ultimately, it will be desirable to include space charge in the analysis,
i.e.'use Poisson's equation; however, the zero space charge problem is more
tractable and provides an easier means of obtaining a first approximation
to the total solution.
Solutions to the Laplace equation in the absence of space charge,
V2V = 0, were developed in the following form.
V(x,y) = -A In cosh (fg) -cos"
cosh (JJJ-) + cos
where A is defined by
V(0,0) = -A in
1 -«" (£)
1 + COS
The effects of spray tube length, tt spray tube spacing, c, and
electrode tube radius, a', were represented in the solutions.
Six electrode geometries were selected for parametric analysis. Table 13
lists their pertinent geometrical parameters. Equipotential plots were
generated for two planes in order to analyze each of these geometries. The
first plan (x-y) is normal to the collector plates and the spray tubes, and
passes through the tips of the spray tubes. The second plane (y-z) is normal
to the collector plates and the electrode tube, and passes through the
centerline of a spray tube. Figures 5 through 15 present the equipotentials
generated. The equipotentials are labelled as their ratio to electrode
potential. The electrode area intercepted by the x-y or y-z plane analyzed
is shown in cross-section on these figures.
25
-------
TABLE 13. ELECTRODE GEOMETRY PARAMETERS
CASE
1
2
3
4
5
6
S'PRAY
TUBE
RADIUS
a
(mm) (INCH)
0.635 0.025
0.635 0.025
0.635 0.025
0.533 0.021
0.533 0.021
0.533 0.021
COLLECTOR
HALF-SPACING
b
(mm) (INCHES)
63.5 2.5
63.5 2.5
63.5 2.5
31.75 1.25
31.75 1.25
31.75 1.25
SPRAY
TUBE
SPACING
c
(mm) (INCHES)
43.18 1.7
43.18 1.7
43.18 1.7
25.4 1.0
25.4 1.0
25.4 1.0
SPRAY
TUBE
LENGTH
8.
(mm) (INCHES)
38.1 1.5
38.1 1.5
15.88 0.625
22.03 0.8675
5.33 0.21
34.3 1.35
ELECTRODE
TUBE
DIAMETER
a1
(mm) (INCHES)
9.52 0.375
12.7 0.50
9.52 0.375
4.76 0.1875
4.76 0.1875
4.76 0.1875
ro
-------
ro
L
••— b
COLLECTOR PLATE
ELECTRODE TUBE
RADIUS a1
——
nnn i
rf
SPRAY TUBE
RADIUS a
—
Figure 4. CDS electrode geometry.
-------
Figure 5. Case 1, electrode geometry, x-y equlpotentials.
28
-------
PARAMETRIC ANALYSIS
Figure 5 illustrates typical electric fields surrounding the spray needle
tips. It is interesting to note that the field lines do not go to zero
potential between the spray tips, that the field is most intense near the tips,
and is weakest in the regions between tips and at the collector plates.
Figure 6 gives further definition of the fields at the spray tip. They are
more intense going towards the collector plates than they are in the flow
direction (z-axis).
Figure 7 and 8 show that increasing electrode tube diameter from 19.1 to
25.4 mm (0.75 to 1.0 in.) has little effect on the electric fields near the
spray tips. As would be expected, there is some distortion of the electric
fields in the vicinity of the electrode tube.
Shortening the spray tubes from 38.1 to 15.88 mm (1.5 to 0.625 in.)
length tends to weaken the electric field at the tips, as can be seen in
Figure 9. The field distribution in the flow direction for this case is
shown in Figure 10.
Figure 11 illustrates typical electric fields surrounding the spray
needle tip in a more compact geometry having half the collector spacing
examined above. The field distribution is very similar to Case 1 (Figure 5),
but is about twice as intense because of having smaller physical dimensions.
Figure 12 shows the field distribution in the y-z plane. When compared with
Case 1 (Figure 6), less distortion is seen near the needle-to-electrode-tube
interface.
Figure 13 shows a very short spray needle, 5.33 mm (0.21 in.) long, in
the compact geometry. Shortening the needle to this length severely weakens
the electric field at the needle tip, because of the dominant influence of
the electrode tube.
Increasing the needle length from 22.03 to 34.3 mm (0.8675 to 1.35 in.)
increases the electric field only slightly at the needle tip, as can be seen
by comparing Figure 14 with Figure 11. Figure 15 shows how the axial field
distribution is elongated further along the flow direction with the longer
needle.
29
-------
Figure 6. Case 1, electrode geometry, y-z equlpotentials
30
-------
Figure 7. Case 2, electrode geometry, x-y equipotentials,
-------
Figure 8. Case 2, electrode geometry, y-x equipotentials
32
-------
CO
CO
Figure 9. Case 3, electrode geometry, x-y equipotentials,
-------
Figure 10. Case 3, electrode geometry, y-z equlpotentials,
34
-------
CO
en
Figure 11. Case 4, electrode geometry, x-y equipotentials,
-------
00
Figure 12. Case 4, electrode geometry, y-z equipotentials.
-------
CO
Figure 13. Case 5, electrode geometry, x-y equipotentials.
-------
CO
oo
Figure 14. Case 6, electrode geometry, x-y equipotentials
-------
Figure 15. Case 6, electrode geometry, y-z equipotentials.
-------
SECTION 5
HIGH VOLTAGE WATER SUPPLY ISOLATION
INTRODUCTION
The TRW Charged Droplet Scrubber (CDS) employs the principles of
electrostatics to generate water droplets having an extremely high electrical
charge. This is achieved by conducting the water through and ejecting it from
high voltage electrodes. To accomplish this on a continuous basis, it is nec-
essary to supply water from a source at ground potential to the electrodes at
high potential without excessive power losses.
The existing design provides the necessary isolation utilizing the resis-
tance of the supply water flowing through non-conducting plastic pipe.
Although simple, the system level of isolation changes as the water conduc-
tivity varies. Since it is unlikely that a constant water conductivity can
be maintained without excessive costs, an alternate water supply technique
is needed. To this end, a design improvement task was initiated to develop
a water supply system that is independent of water electrical property
variations.
CONCLUSIONS AND RECOMMENDATIONS
The air gap isolation system design is capable of providing high voltage
isolation for the Charged Droplet Scrubber where the supply water has an
electrical conductivity of up to 60,000 micromho and where the potential
difference across the water spray gap is as high as 50 KV.
The solid state resistor bank design will provide the necessary electrode
state isolation and current limiting functions to meet the operational require-
ments of the Charged Droplet Scrubber.
DESCRIPTION OF EXISTING SYSTEM
Presently the isolation system consists of the electrical resistance
provided by a long column of supply water contained in a plastic pipe.
Normally, more than one electrode stage is operated from a single water
isolation column and single power supply system. When more than one CDS stage
is operated from the same power supply, it is necessary to connect each stage
electrically to the power supply through a resistance. This resistance serves
as a current limitor for the power supply in the event of an arc on the stage
and also gives partial electrical isolation between the stages so that an arc
on one stage does not significantly effect the voltage to the other stages
connected to the common supply. These stage isolation resistors are also
water columns of the supply water.
40
-------
Using a water column of the supply water for the stage isolation and
current limiting resistor has the advantage of being self cooled, but it also
has the disadvantage of requiring a fairly constant water conductivity. If
the water conductivity varies over any significant range, the power dissipated
or lost in the current limiting resistors can be quite high if it decreases,
or the stage isolation and current limiting functions can be degraded, if it
increases. A schematic of a typical water column high voltage isolation sys-
tem with four stages operating from a single power supply is shown in
Figure 16.
APPROACH
The approach taken to achieve isolation, was a design where water could
be transferred from a supply at ground potential to a reservoir at high voltage
in the form of discrete droplets separated by air gaps. The air surrounding
the droplets act as a current impeding dielectric. Spray nozzles generate the
liquid droplets and are then collected in an electrically insulated container
and fed to the stage header water distribution system by gravity through a
conducting pipe. The water could be supplied from the container to the elec-
trodes with metering pumps; however, level detectors, solenoid valves, pumps,
motor and other associated controls would further complicate the system.
Figure 17 presents a diagram of the Air Gap Isolation System Design.
Current limiting and stage isolating resistors are still required in the
high voltage circuit. When the water column resistors were used, the flowing
water provided the necessary cooling. Resistors having a fixed value however
would now be necessary for current limiting and stage isolation in the spray
nozzle system. As a result a cooling system to dump the heat dissipated by
the resistor is now also necessary. The design of the isolation resistor bank
is presented in Figure 18.
RESULTS AND DISCUSSIONS
The high voltage isolation assembly and the stage isolation/current
limiting assembly would be designed to accommodate a single stage of an
existing Charged Droplet Scrubber unit having forty seven electrodes per
stage. This would require water to be supplied at the rate of approximately
49.2 fc/min (13 gpm) and have a stage isolation resistance of approximately
100 K ohms.
Since the approach with respect to the high voltage/water supply isolation
is new technology, subscale testing would be performed prior to proceeding to
the full-scale design. The technology utilized for the stage electrical iso-
lation and current limiting system, however, is well established. Therefore,
the subscale test phase for this assembly was not deemed necessary.
Water Isolation Tank Assembly
Two different type nozzles for supplying water to the CDS through a high
voltage gradient were tested. One was a shower head nozzle composed of indi-
vidual spray tubes in place of orifices. The other was a swirl nozzle type in
which a tangential component is imparted to the water prior to expulsion.
Figures 19 through 22 presents the two nozzle configurations. The two nozzles
41
-------
ro
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Figure 16. Water column high voltage Isolation system.
-------
AUTOMATIC
VOLTAGE
CONTROL
UTILITY POWER
1 <>, 480 V
FLOW
WATER SOURCE (GROUND POTENTIAL)
FLOW CONTROLLER
SWIRL SPRAY NOZZLE
WATER ISOLATION TANK
(HIGH VOLTAGE)
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Figure 17. Air gap isolation system.
-------
„„„„. .8, ,1 ,,„„„„. l~
' T ' 1 ' ! ! •"•il-'""| r 'I
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Figure 18. Isolation resistor bank.
-------
Figure 19. Shower head nozzle at zero potential.
Figure 20. Shower head nozzle at -40 KV,
45
-------
Figure 21. Swirl nozzle at zero potential
Figure 22. Swirl nozzle at -40 KV.
-------
were operated at 2.1 fc/min (0.55 gpm) and were located 102 mm (4 in.) above
the water collecting container. A voltage differential of up to 40 KV was
maintained between the nozzle and collector. No leakage current was observed
with a meter having a 100 yA sensitivity. The water used was doped with
sodium chloride and had a conductivity of 60,000 ymho/cm. Other nozzle tests
were conducted with tap water having a conductivity of 500 ymho/cm and with water
doped with a surfactant having a surface tension of 4.0 x 1Q-* N/m. No
leakage current on breakdown was noted in any of the tests with -40 KV applied
to the water collector.
The flow velocity of the water leaving the tubes of the shower head
nozzle is less than the streaming velocity. The streaming velocity is defined
as that velocity corresponding to a stream kinetic energy equal to the energy
required to generate the new surface in the flowing stream. The minimum
streaming velocity, vm, can be expressed as:
v_ =
8 1/2
'm d
P
Where
o surface tension of the liquid
p liquid density
d = flow tube outer or inner diameter, depending on the material
wettabi1i ty
The flow tubes used in the test were wetting and had a 1.59 mm
(0.0625 in) O.D. The corresponding maximum velocity before streaming is
0.6 m/s (*v2 ft/sec). Since the stream velocity is low, the momentum is low
and as can be seen by comparing the difference in droplet trajectories in
Figures 19 and 20 the electrostatic forces alter the droplet flow path. The
flow tubes are used in this type of nozzle rather than holes to insure that
the water streams cannot agglomerate and form a continuous streamer. Also,
the flow tubes have a finite length so that some back pressure is developed
for flow control. The shower head nozzle has demonstrated the capability of
supplying water across a large potential difference without breakdown; how-
ever, the nozzles become large for full-scale CDS units.
The swirl nozzle was tested for isolation because they would be easy to
scale to full size systems. The nozzle shown in Figures 21 and 22 has a
nominal 1.98 mm (0.078 in.) diameter orifice. The water flow velocity is
approximately 11 m/s (*> 37 ft/sec). The flow velocity is about 20 times that
of the shower head nozzle; therefore, the water is leaving with more momentum.
As can be seen by comparing Figures 21 and 22 the electrostatic forces with
applied voltage has negligible affect on flow pattern.
A full-scale swirl type nozzle was also tested. It had an included
spray angle of 60° and a flow rate of 45.4 */min (12 gpm) at 703 g/cm2
(10 psi) inlet pressure. The test was conducted under the same conditions as
47
-------
the subscale units with similar results. There was no measurable current
drain at maximum water flow and with a voltage differential of 50 KV.
A considerable quantity of air is entrained in the high velocity water
jet. This entrained air causes fogging when the water droplets impinge in
the collecting container. The fog is eliminated by using a funnel shaped
water interceptor within the collector. With this configuration the entrained
air moving ahead of the droplet shower exits the collector container on the
outside of the water interceptor. The sprayed water has had a chance to
agglomerate on the funnel surface while still allowing forward flow of the
entrained air. The air then makes a 1800 turn prior to exiting which pre-
vents re-entrainment of water. Figure 23 presents the isolation tank design.
Stage Isolation Resistors
Two types of fixed resistors were evaluated for the application. One
was a wire wound configuration, the other an extruded ceramic power resistor.
After evaluation of the individual specifications, the ceramic configuration
was selected because of the higher operating temperature capability and the
fact that it is essentially non-inductive. Figure 24 presents a photo of the
ceramic resistor chosen for the design. Typically, the maximum operating
range is 20 to 350°C.
To minimize the resistor bank housing volume requirements and to minimize
the temperature rise during state operating condition, the resistor would be
immersed in a silicone fluid to improve the heat dissipation rate. The
liquid chosen for this purpose is General Electric SF-96 silicone fluid which
has a temperature operating limit of 260°C and a dielectric constant of 2.75.
The resistor bank is designed to operate at an ambient temperature of
up to 38°C and accommodate a temperature rise within the bank of approximately
93QC.
48
-------
~r "T~
vo
h
jC
/ •*-»*>»» t+tftm^t t "** ***** jut*****, +t*tfe
i
NOTE: ALL DIMENSIONS ARE IN INCHES
1 Inch • 264 mm
S T~~ 5 f— T~
Figure 23. Water isolation tank.
-------
Figure 24. Ceramic resistor.
50
-------
SECTION 6
EQUIPMENT CORROSION
INTRODUCTION
A flue gas corrosion study was performed as part of the Charged Droplet
Scrubber program funded jointly by the EPA and TRW. The objectives of the
study were to:
• Obtain quantitative data on the performance of 316 CRES
(austenitic stainless steel) of which the main structure and
components are constructed.
• Investigate the feasibility of coatings as a means of improving
the performance of materials exposed to coke oven flue gas
environments.
• Investigate the feasibility of metallic and non-metallic
liners for scrubber construction.
• Investigate alternate materials, both metals and non-metals,
for CDS component and structure applications.
The approach is to use a combination of materials test coupons, coated
portions of the CDS structure and components and electronic corrosion probes
to assess the performance of the test materials under actual scrubber opera-
ting conditions. At approximately the midpoint in the run, the specimens were
removed, inspected and analyzed. A rough screening was performed and the
remaining candidate material specimens replaced for continued testing. At the
end of the test operation, the remaining specimens were removed and analyzed.
The type of test materials, coatings and probes and their locations
are described in Appendix B. Also shown in the appendix is a diagram of the
CDS unit.
Coupon test samples (metal and non-metal) were installed in the upper
casing (hood) and in the lower casing under the baffles. The lower casing
location produced the most severe service since the temperatures of the samples
can reach that of the incoming gas stream and the wash water is only partially
effective due to the screening caused by the baffles. Some of the samples
were coated or lined with organic materials.
51
-------
Coatings were applied to the electrode access doors, electrodes, wash
couplings, upper casing (hood) surfaces, and lower casing surfaces as well
as test coupons.
The electronic corrosion meter (Corrosometer, Magna Corp.) probes were
used to serve as an in-process indicator/monitor for corrosion behavior. In
addition, the Corrosometer data was compared to corrosion data from test
coupons.
Analysis techniques employed included visual inspection, weight change
determinations, metallographic examination, and hardness measurements.
CONCLUSIONS
Of the metallic coupons tested, the commercially pure titanium, Ti-0.2 Pd
and Incology 825 alloys performed best, Hastelloy C-4, TI - Code 12, and Inconel
617 had very good corrosion resistance when exposed to the lower casing gas stream
but were attacked in the upper casing gas stream. The chemical lead samples
performed satisfactory in the lower casing and lead lining of the casing appears
to be a strong candidate for a long life design. The 316 CRES samples showed
fair corrosion resistance in both the upper and lower casing gas streams.
The pitting/crevice behavior of the stainless steels and nickel alloys
roughly follows the molybdenum content. Thus, the relative performance in
order of increasing corrosion resistance would be predicted to be:
Ni (0 percent Mo), 304 CRES (0 percent Mo), Inconel 601 (0 percent Mo),
316 CRES (3 percent Mo), Incoloy 825 (3 percent Mo), Inconel 617 (9 per-
cent Mo) and Hastelloy C (16 percent Mo).
This sequence held quite well for the samples tested in the lower casing
gas stream except that Incoloy 825 performed better than Inconel 617. However,
in the upper casing gas stream, the Hastelloy-C coupon was severely attached
with its relative performance falling between that of pure nickel and
Inconel 601. No explanation for this behavior has been identified at this
time.
In general, the corrosive attack was more severe for metallic coupons
exposed to the upper casing gas stream than those in the lower casing. The
upper casing coupons were not exposed to the amount of water as were coupons
in the lower casing since they were above the electrode headers. Therefore,
the coupons were in a moist atmosphere with temperatures in the 18.2°C to 33.8°C
range, but did not get the cleaning/diluting effect which the lower casing
samples experienced.
Therefore, the chloride concentration would be expected to be higher on
the upper coupons which would tend to promote pitting and crevice corrosion
in the stainless steels and nickel alloys. In addition, the moisture cling-
ing to the coupons would tend to collect and concentrate sulfuric acid. That
is, as water evaporated the higher boiling point of the sulfuric acid causes
the concentration to increase. Figure 65 shows the boiling point curve for
52'
-------
sulfurlc add. It is not clear which factors caused the pitting attack of the
Ti-Code-12 coupon in the upper casing. This alloy is specifically formulated
to retard pitting and crevice attack.
The sulfurlc acid concentration on coupons in the lower casing would be
expected to be high. However, some on wetting/washing of the samples would
occur even though the baffles partially screened the coupons from the water
flow, so that some dilution would occur. In cases, where dilution did not
occur, sulfuric acid concentration of the order of 70 percent is possible .
The wall temperatures run cooler than the gas temperatures and, all other
other parameters being equal, the corrosion rates would be expected to be
lower than for the coupons. This was borne out by the corrosion meter measure-
ments in the upper casing and in the lower casing below the baffles for the
316 CRES. The probe located in the lower casing above the baffle showed a
higher rate, Table 17, but no coupons were mounted in this region so that a
direct comparison can not be made.
None of the coating systems tested were able to survive the CDS environ-
ment. The combination of temperature, gas velocity, and chemical environment
caused blistering, debonding or cracking. The epoxy EA 919 coating gave some
degree of protection to the electrode headers (which run cool due to the
internal water flow) and the upper casing doors. However, long term survival
is unlikely.
The elastrometric liner materials subjected to the gas stream checked or
cracked. However, some of the elastrometric materials performed well as
gaskets, seals and baffle shims. Viton rubber showed excellent resistance in
these configurations and neoprene elastromer performed well as a seal in the
upper casing. A Teflon/glass fabric (Armalon) liner was applied to an upper
casing door and showed no signs of degradation. Vinyl shrink tubing performed
well over electrode header connectors since the temperature in these regions
was quite low due to water flow inside the electrodes.
Of the fiberglass reinforced plastic panels, only the polybutadiene showed
acceptable resistance. Again the combination of temperature (up to 177°C) and
concentrated sulfuric acid was too aggressive an environment. It is possible
that some of these materials, specifically Ashland 197/3 and Ashland 800,
would perform satisfactorily on the walls where the temperatures are lower
and the washing action of the water would prevent high concentrations of
sulfurlc acid to form.
The overall performances of the various materials are shown in Table 19.
RECOMMENDATIONS
Based upon the inspection and analysis, preliminary recommendations have
been made for materials and design changes and maintenance procedures for coke
oven application units. The recommendations are divided into short term (up
to two years), intermediate term (two- to ten years), and long term, (greater
than ten years) life requirements.
53
-------
Two Year Service
• 316 CRES upper and lower casings, doors and hood. Inspect
periodically. Local repairs as necessary (weld-on doublers).
• 316 CRES electrodes. If perforation occurs, replace with
titanium electrodes as they fail.
• Viton door seals.
• Viton baffle shims.
t 316 CRES wash system.
• 316 CRES baffles. Replace as required.
Two-To-Ten Year Service
• pH control and inhibitors.
Long-Term Service
t Lower casing lined with lead.
• Lead lined baffles.
0 Upper casing and doors lined with lead, Hypalon elastomer sheet,
or neoprene elastomer sheet.
• Titanium electrodes, headers, couplings, wash system, collector
plates.
• Viton door seals and baffle shims.
INSPECTION AND ANALYSIS
The test coupons from the upper and lower casing were removed at midpoint
and analyzed. A summary of the observations is given 1n Tables 14 and 15.
The coupons which exhibited severe degradation were screened from the program
and testing of these materials was discontinued.
Stainless Steel
The corrosion resistant stainless steels (CRES) subjected to the lower
casing environment exhibited pitting and crevice corrosion attack. 304 CRES
was more severely attacked than 316 CRES, see Figures 25 and 26. The 304 CRES
specimens showed attack ranging from small multiple pits to cracking of the
specimen in the most heavily pitted regions, Figure 25. Some 316 CRES speci-
mens were only lightly attacked, or not attacked at all, while others showed
extensive pitting over the entire coupon surface, Figure 26. Crevice attack
was normally present around the attachment bolt holes.
54
-------
TABLE 14. CONDITION OF MATERIAL TEST COUPONS - LOWER CASING
ROW-LOCATION
1-1
1-2
2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
2-10
2-11
3-1
3-2
3-3
3-4
3-5
3-6
3-7
3-8
3-9
3-10
3-11
4-1
4-2
4-3
4-4
4-5
4-6
4-7
4-8
4-9
5-1
5-2
5-3
5-4
5-5
5-6
5-7
6-1
6-2
6-3
6-4
SAMPLE NO.
s-( )c
S-23K
304-18
S-14W
304-7PS
Ti-12-1
Ti-PD-1
Ti-1
304-17
Ni-5
304-1 ORO
S-1T
304-16
316-18
S-13RO
304-3T
1825-5
Ni-1
316-17
1617-1
1607-2
316-13W
S-8PS
316-16
316-4E
315-12RO
AT382/05
AT711-1
AT382-1
AT580-1
317-7PS
316-AW
316-1T
ASH 7241-29
ASH 72L-22
ASH 7240-39
ASH 197/3AT-5
ASH 800-25
ASH 197/3-5
ASH 800FR-20
ASH 800PR-21
ASH 197/3-4
ASH 800-24
ASH 197/3AT-6
REMARKS
Surface attack
Coating peeled
Slight surface attack
Coating failed
Coating peeled
Missing
No attack
Slight surface etch
Surface attack-cracks or pits
Pitted
Coating failed
Coating blistered
Slight attack
No visual attack
Coating failed
Coating peeled at edge, some
No attack
Badly pitted
No attack
No attack
Pitted
Coating failed
Coating blistered
Pitted
Coating failed
Coating failed
Surface etching, cracking &
Surface etching, cracking &
Surface etching, cracking &
Surface etching, cracking &
Coating blistered
Coating failed
Coating delaminated at edges
Surface etched
Missing
Surfaced etched
Missing
Sample cracked & etched
Some edge attack
One face etched
Some surface etch
Some edge attack
Some surface etch
Some edge attack
blisters
crazing
crazing
crazing
crazing
(continued)
55
-------
TABLE 14. (continued)
ROW-LOCATION
6-5
6-6
6-7
7-1
7-2
7-3
7-4
8-1
8-2
9-1
9-2
9-3
9-4
9-5
9-6
9-7
9-8
9-9
9-10
9-11
9-12
10-1
10-2
10-3
10-4
10-5
10-6
10-7
10-8
11-1
11-2
11-3
11-4
11-5
11-6
11-7
11-8
11-9
11-10
12-1
12-2
SAMPLE NO.
ASH 7240-40
ASH 72L-21
ASH 7241-30
HY-180
HY-132
P33-1
C31-1
Pb-2
Pb-1
316-( )NB
316-( )NB
S-( ) NB
S-( ) NB
316-26N
316-25N
S-18N
S-17N
316-29H
316-28H
S-( )H
S-( )H
316-22
304-9PS
Ti-2
TiPd-2
Ti-12-2
316-11RO
304-1 T
304-12
304-1 6RO
S-5E
1601-4
11617-3
316-23
304-21
316-8PS
1825-2
304-5E
S11RO
304-20
S-3T
REMARKS
Edges etched
Surface and edge etch
Edges etched
Missing
Slight discoloration
De laminated - failed
Del ami na ted - failed
No attack
No attack
Checking, rubber hardened
Checking, rubber hardened
Checking, rubber hardened
Checking, rubber hardened
Coating failed
Coating failed
Coating failed
Coating failed
Local failure - blisters
Local failure - blisters
Coating failed
Coating failed
No attack
Some peeling at corners
No attack
No attack
No attack
Coating failed
Some peeling at edge
No attack
Missing
Coating failed
Pitted
No attack
No attack
Some pitting
Peeling at corners
No attack
Coating failed
Coating failed
Slight attack
Coating blistered
(continued)
56
-------
TABLE 14. (concluded)
ROW-LOCATION .
12-3
12-4
12-5
12-6
12-7
12-8
12-9
12-10
13-1
13-2
13-3
13-4
14-1
14-2
15-1
16-1
17-1
SAMPLE NO.
N1-3
304- 14W
316-6E
316-3T
S-16W
304-1 5W
S-10PS
316-20
304-28K
Hast B-l
Hast C-l
s-( )c
S-24K
304-29K
4092-1
4030-1
4020-1
REMARKS
Pitted
Coating failed
Coating failed
No attack
Coating failed
Coating failed
Blistered
Some attack
Coating peeled
No attack - some darkening
No attack
Surface etched
Coating peeled
Coating peeled
Surface etched
Surface etched
Surface etched and flaked off
The CRES sample 1n the upper casing showed similar behavior with the
304 CRES pitting over most of the exposed surface and the 316 CRES showing
some pitting and crevice attack near the attachment holes. Figures 27 and 28
show the appearance of typical 304 CRES and 316 CRES coupons, respectively.
Nickel Alloys
Pure nickel samples were severely attacked by the CDS environment.
Extremely heavy pitting and crevice corrosion was noted on all lower casing
specimens, Figure 29. The Inconel 601 specimens also showed severe attack.
Intergranular corrosion caused grains to spall off the surface which resulted
in multiple pits, Figure 30. The bolt attachment areas were attacked by
crevice corrosion. The nickel alloys containing high amounts of molybdenum,
Inconel 617, Incoloy 825, Hastelloy C-4 and Hastelloy B, were not attacked,
although some discolorization was noted on the Hastelloy B coupon, Figures 31
and 32.
The nickel and Inconel 601 specimens exposed to the upper casing environ-
ment were pitted over their surfaces as shown in Figures 33 and 34. In con-
trast to their performance in the lower casing, Incoloy 825 and Inconel 617
all showed evidence of pitting attack in the upper casing, see Figures 35 and
36. The Hastelloy C sample was badly pitted even though it showed excellent
resistance to attack in the lower casing, see Figure 36.
57
-------
TABLE 15. CONDITION OF MATERIAL TEST COUPONS - UPPER CASING (HOOD)
ROW- LOCATION
1-1
1-2
1-3
1-4
1-5
1-6
1-7
1-8
2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
2-10
2-11
3-1
3-2
3-3
3-4
3-5
3-6
3-7
3-8
SAMPLE NO. -
304-2T
304- 13W
304-8PS
304-1 1RO
304-4E
Haste Hoy C
1825-1
1601-3
T1 PD-3
Ti-12-3
316-19
304-24
Ni-2
1617-2
Ti-12
316-2T
316-15W
316-9PS
316-10RO
316-21
304-19
S-4E
S-12RO
S-9PS
S-5W
S-2T
316-5E
REMARKS
Coating blistered,
Coating failed
Coating blistered,
Coating failed
Coating failed
Surfaced pitted
Surfaced roughened
Surfaced pitted
Discoloration
Some pitting
Edges pitted
delaminatlon
peeled
Pitting, crevice attack
Pitting attack
Pitting attack
Discoloration
Coating blistered,
Coating failed
Coating blistered
Coating failed
Good
Pitting attack
Coating failed
Coating failed
Missing
Coating failed
Coating peeled
Coating failed
del ami nation
Titanium Alloys
The commercially pure titanium coupons and the T1-0.2 Pd and T1-Code 12
coupons all showed good resistance to attack in the lower casing. Some slight
surface etching was noted, Figure 37. Otherwise, the surfaces appeared nor-
mal except for some staining which was removable with a non-metallic brush
and detergent. The Ti and Ti-0.2 Pd coupons in the upper casing also exhibi-
ted excellent resistance to attack, Figure 38. However, the T1-Code 12 coupon
was pitted after exposure to the upper casing environment.
Lead
The chemical lead specimens were discolored due to the formation of a
surface film but had not sustained pitting or crevice attack. The film was
adherent and very difficult to remove by brushing and washing, Figure 39. All
specimens were mounted in the lower casing.
58 •
-------
_
1 ; •; :W-
-
i •
•
•
a
-
r- - "
,-.-. )
*
Figure 25. Coupon 304-17 (left) and 304-18 (right). Severe pitting
attack with 304-17 showing cracks in heavily pitted
regions. Micrograph showing section through pitted
area. Lower casing.
59
-------
Figure 26.
Coupons 316-23 (top) showing mild attack and 316-16
(bottom) which has extensive pitting attack. Lower
casing.
60
-------
*
Figure 27. Coupon 304-24. Pitting and crevice corrosion. Upper casi
ng
61
-------
Figure 28. Coupon 316-19. Some pitting attack. Upper casing
62
-------
Figure 29. Coupon Ni-1. Severe pitting attack has occurred over
entire surface. Lower casing.
63
-------
Figure 30. Coupon 16-1-2. Extremely severe intergranular attack
with spalling of surface grains. Lower casing.
64
-------
Figure 31. Coupons 1825-2 (left) and 1825-5 (right
of corrosive attack. Lower casing.
No indications
65
-------
c'* ib
Figure 32. Coupons Hast. B-l (left) and Hast C-l (right). Some
discoloration of the Hastelloy B specimen. Hastelloy
C-4 not attacked. Lower casing.
66
-------
Figure 33. Coupon Ni-2. Severe pitting attack. Upper casing,
-------
Figure 34. Coupon 1601-3. Pitting attack on surface. Upper casing
68
-------
Figure 35. Coupons 1617-2 (left) and 1825-1 (right). Surface
roughened (incipient pitting). Upper casing.
-------
Figure 36. Hastelloy C coupon. Severe pitting attack. Upper casi
ng.
70
-------
Figure 37. Coupons Ti-1 (top) and TiPd-1 (bottom). Some surface
etching of titanium specimen. Lower casing.
-------
Figure 38 Coupons Ti-12 (upper left), TiPd-3 (lower left) and Ti-12-3
(upper and lower right). The Ti-12-3 coupon has pitted.
Upper casing.
72
-------
Figure 39.
Coupon Pb-1. Surface film formed which was difficult
to remove. Lower casing.
73
-------
Non-Metallic Coatings
All of the coatings tested showed some degradation, either of the coating
itself or of the coating/substrate bond. The EA919 epoxy (E), vinyl plastisol
(W) and alkyd (RO) all failed by coating attack, blistering and peeling, see
Figures 40 through 42. In some cases the coating disappeared from the surface
of the coupons during exposure to the CDS environment. The polyvinylidene
fluoride (K) coatings failed by adhesion as evidenced by blistering and peeling
of the coating from the substrate, Figure 43 through 45. However, the coating
materials themselves appeared to be unaffected by exposure. Both the poly-
chloroprene (N) and polysulfonated rubber (H) coatings were attacked and crack-
ing was noted, Figures 46 and 47.
The glass flake filled polyester (Cielcote) and filled vinylester coat-
ings showed surface etching and, in one case, portions of the coating flaked
off, Figures 48 and 49.
Twelve water spray nozzle couplings in the upper casing were coated with
epoxy, alkyd, vinyl, and polyphenylene sulfide (3 each) and exposed to the
normal operation environment. The epoxy, vinyl, and alkyd coatings failed
while the polyphenylene sulfide coating was still intact when the test was
terminated (the PS coating was damaged during the coupling removal operation).
Three tested couplings are shown in Figure 51.
Coatings were applied to lower casing walls (hypalon and neoprene elas-
tomer), upper casing doors (epoxy, alkyd, and vinyl), the electrode headers
(epoxy, vinyl, and alkyd) and the upper casing walls (hypalon, neoprene,
vinyl and alkyd). Only the epoxy coatings on the upper casing doors and
electrode headers did not fail, although they discolored and exhibited some
blistering. All of the other coatings failed, usually in the bond. It
should be noted that substrate preparation was not possible and the coatings
were applied in the field after solvent cleaning with acetone. Therefore,
good adhesion would not be expected.
The bonded polychloroprene (neoprene) (NB) liner material showed surface
checking, and cracking, Figure 50. The elastomer hardened from a shore A of
70 to 90 indicating chemical attack.
An Armalon (teflon/glass fabric) liner applied to an upper casing door
showed excellent resistance to attack.
Non-Metallic Structural Panels
Fiber reinforced polyesters, vinylesters, furans, and polybutadiene were
tested in panel form in the lower casing. In addition, polyvinylchloride
(PVC) was tested as shrink tubing and polyhexafluoropropylene (Viton) as
gasketing material.
The polyesters showed degrees of degradation ranging from surface etch-
ing to delamination as shown in Figures 52 through 58. The vinylester panel
showed some surface etching and edge attack, Figure 59. The furans also
74
-------
Figure 40. Coupons 316-4E (left) lower casing and 304-4E (right), upper
casing. EA 919 epoxy coating has failed exposing substrate.
75
-------
Figure 41. Coupons S-13RO (top) lower casing and 316-10RO (bottom^
upper casing. Coating failed exposing substrate.
76
-------
Figure 42. Coupons 316-14W (left) lower casing and 216-15W (right)
upper casing. Coating failed exposing substrate.
Figure 43. Coupons 316-7PS (left) lower casing and 316-19PS (right)
upper casing. Coating failed in adhesion causing
blistering and delamination.
77
-------
Figure 44. Coupons 304-3T and Sl-T (upper) lower casing and 216-2T upper
casing. Coating failed in adhesion causing blistering.
78
-------
Figure 45. Coupons 304-28K (left) and S-24K (upper) lower
casing. Bond failed causing delamination.
Figure 46. Coupon S-18N lower casing. Coating cracked and delaminated.
79
-------
X
-^
\ /
'A
Figure 47. Coupon 316-28H lower casing. Surface etched and cracked.
80
-------
rigure 48. Steel coated with g"iass flake filled polyester (ceilcote)
Surface has been etched by the gases.
81
-------
Figure 49. Steel coated with glass filled vinylesters. Surfaces have
been etched. 4030-1 sample shows coating failure by
chipping off at attachment hole.
82
-------
Figure 50.
Coupon 316-NB. Neoprene elastomer liner shows surface
cracking (checking). Lower casing.
f 3
-------
Figure 51.
Water spray nozzle couplings from upper casing. Couplings
are coated with polyphenlyene sulfide (PS), alkyd (RO),
vinyl (W) and epoxy (919). The PS coating was intact
(although damaged during the removal operation). The other
coatings failed.
84
-------
Figure 52. Coupons AT382-1 (left) and AT382/05 (right) bisphenol polyesters
Surface checking and cracking. Lower casing.
5
-------
Figure 53. Coupon AT-11-1 flame retarded polyester.
checking. Lower casing.
Surface etching and
86
-------
Figure 54. Coupon ASH7240-40 IPA polyester.
and cracks. Lower casing.
Surface attack, pits
87
-------
Figure 55. Coupon A5H7241-29 IPA polyester. Surface etching,
cracking and pitting. Lower casing.
-------
Figure 56. Coupon ASH 197/3-5 polyester. Surface etching, pitting and
crazing. Lower casing.
89
-------
Figure 57. Coupon ASH 197/3AT-6 polyester.
pitting. Lower casing.
Surface crazing and
90
-------
Figure 58 Coupon ASH 72L-21 flame retarded polyester
cracking and pitting. Lower casing.
Surface checking ,
91
-------
Figure 59. Coupon AT580-1 bisphenol vinylester.
and etched. Lower casing.
Surface cracked
92
-------
showed surface etching and edge attack, Figure 60. The polybutadiene panel
discolored and showed some minor pitting near the edge, Figure 61.
The PVC shrink tubing was installed over water spray couplings and
electrode couplings and showed visible signs of degradation.
The temperature of the shrink tubing was low due to water flow. Some
signs of crevice corrosion of the stainless steel was noted under some of
the shrink tubing liners.
The viton seals showed no degradation due to exposure to the CDS operating
conditions.
Braced Nozzle/Grommet Joint
In order to provide a more reliable joint between the electrode nozzles
and the mounting grommets, a brazed configuration was tested. It was also
hoped that less arcing, and resulting erosion of the nozzles, would occur with
a positive electrical path between nozzle and grommet. Excessive arcing had
resulted in failure of some nozzles after a baffle support failure.0)
Several nozzle/grommet assemblies were crimped and vacuum brazed at TRW
using Gapasil No. 9 (Ga-Pd-Si) braze alloy.* After initial process develop-
ment problems, good flow and filletting was obtained, Figure 62. The nozzle
assemblies were installed on several electrodes and exposed to the CDS
environment for approximately 100 hours. The braze fillet was attacked pre-
ferentially along second phase particles, Figure 63. The braze on the water
side of the crimp appeared to be slightly attacked at the exposed edge but
otherwise intact. The nozzles showed no evidence of attack.
Weight Change Measurements
The metallic specimens were weighted before and after exposure to deter-
mine weight change. These data are shown in Table 16. In this Table, uniform
corrosion rates are shown which were calculated from the weight change data.
Note that the nickel and Inconel 601 samples pitted badly so that the uniform
corrosion value given for these metals should not be used except for a quali-
tative comparison. The uniform corrosion rate for 316 CRES was determined
from specimens which showed little or no pitting attack. The best resistance
to attack was exhibited by titanium, Inconel 617, and Incoloy 825.
Electronic Corrosion Meter Data
Five electronic corrosion probes (Magna Corporation 21343/W40/8020 with
316 CRES elements) were installed on the north side of the north CDS unit.
The data taken are shown in Table 17. Figure 64 shows the Corrosometer probes
used in the test.
*Western Gold and Platinum, Inc.
93
-------
Figure 60.
Coupons ASH800-28 furan (left) and ASH800FR-20 flame retarded
furan. Surface cracking, checking and pitting. Lower casing.
94
-------
Figure 61. Coupon HY132 polybutadiene.
Lower casing.
Some pitting attack at edge
:
-------
Figure 62. Nozzle/grommet joints
brazed (right).
Crimped only (left) and
96
-------
•
-
• • • ••
Figure 63. Appearance of brazed joint after exposure of 100 hours.
Brazed fillet attacked along second phase. Joint inboard
(toward the header) of crimp unaffected.
97
-------
TABLE 16. WEIGHT CHANGE OF METALLIC TEST COUPONS
MATERIAL
TESTING
316 CRES
Nickel
Inconel 601
Inconel 617
Incoloy 825
Hastelloy B
Hastelloy C-4
C.P. Titanium
Chemical Lead
LOWER CASING
NO. OF
COUPONS
5
3 (P)
2 (P)
2
2
1
1
2
2
AVE. WT.
LOSS (g)
0.2950
12.1532
1.1154
0.3828
0.1798
3.397
0.1807
0.0794
0.3311
UNIFORM
CORROSION
RATE (mmpy)
0.135
5.790
0.500
0.165
0.079
1.186
0.061
0.063
0.244
UPPER CASING
NO. OF
COUPONS
2
1 (P)
1 (P)
1
1
-
1 (P)
1
-
AVE. WT.
LOSS (g)
0.5361
9.0497
0.9463
0.7537
0.5064
-
1.6599
0.2329
-
UNIFORM
CORROSION
RATE (mmpy)
0.241
3.683 (P)
0.201 (P)
0.328
0.226
-
1.407 (P)
0.188
-
(P) Pitting attack - uniform corrosion rates should be used for
qualitative comparison only.
TABLE 17. CORROSOMETER DATA
PROBE NO.
1
2
3
4
6
LOCATION
A -
C -
D -
L -
K -
CDS Inlet Duct
Lower Casing -
Lower Casing -
Above Baffles
Upper Casing -
Upper Casing -
f'
East End
West End,
East End
West End
UNIFORM CORROSION RATE
0.012
0.093
0.309
0.041
0.038
(mmpy)
98
-------
Figure 64. Electronic corrosion meter (Magna Corporation CK-3) and type
of probe (2143/W40/8020) used for the in-process corrosion
rate measurements.
99
-------
Thermal/Chemical Environment
Inlet gas temperature for the north unit was recorded at the same time
that Corrosometer readings were taken. The temperature probe located near
port A indicated that the inlet gas temperature ranged from 175.5°C to 190.5°C.
In order to assess the wall temperatures of different parts of the unit, a
thermal profile was run by inserting probes into the Corrosometer ports in the
lower casing and the stage area. In addition, upper casing wall temperature
was taken at three points on the south side of the unit. The results are shown
in Table 18.
Carbonaceous deposits were found on walls, doors, internal structures,
baffles and test coupons. An analysis of the deposit indicates up to 1.7
weight percent chloride is present. When water is added to the deposit, the
resulting solution exhibits a pH of between 1 and 2.
The coke gas stream contains C, S02, H2S, 02, NOx, CH3, H2, HCN, S, CO,
C02, N2 and possibly other hydrocarbons. Water reacts in the gas stream to
form sulfuric acid and, to a lesser extent, carbonic acid, nitric acid and
other corrosive fluids.
Wastewater and domestic feed water samples were analyzed to establish
the chemistry before and during CDS operation. The data sheets are included
in Appendix C. The key changes include:
a)
The chloride content dropped from 60 ppm (domestic water) to
about 25 ppm (wastewater).
b) The sulfate content increased from approximately 10 ppm to
220 to 286 ppm.
TABLE 18. WALL TEMPERATURES OF NORTH CDS UNIT
PORT
A
B
C
D
I
F
H
G
-
-
—
LOCATION
Inlet Duct
Lower Casing-West End (Below Baffles)
Lower Casing-East End (Below Baffles)
Lower Casing-Midpoint (Above Baffles)
Collection Section-West End (Upper (Door #2))
West End (Lower (Door #2))
Midpoint (Middle (Door #5))
East End (Lower (Door #9))
Upper Casing-West End (Above Door #2)
Upper Casing-Midpoint (Above Door #4)
Upper Casing-East End (Above Door #9)
TEMPERATURE (°C)
142
136
84
97
50
45
66
53
68
79
59
100
-------
TABLE 19. SUMMARY OF MATERIALS PERFORMANCE
MATERIAL
EXCELLENT
GOOD
FAIR
POOR
Lower Casing - Gas Stream
Metals
Coatings
Liner
Reinforced and
Filled Coatings
Titanium C/P
Ti - .2 Pd
Ti - Code 12
Haste11oy C-4
Incoloy 825
Chemical Lead
Inconel 617
316 CRES (P)
Haste Hoy B
Neoprene (T)
304 CRES (P)
Nickel (P)
Inconel (I)
601
Teflon (A)
Kynar (A)
Polyphenylene Sulfide (A)
Epoxy (A) (T)
Vinyl (A) (T)
Alkyd (A) (T)
Hypalon (A) (T)
Neoprene (A) (T)
Ceilcote 252 (T) (C)
Plasites:
4020 (T) (C) (A)
4030 (T) (C)
4092 (T) (C)
(continued)
-------
TABLE 19 (continued)
MATERIAL
EXCELLENT
GOOD
FAIR
POOR
Lower Casing - Gas Stream
Fiberglass
Reinforced
Plastic
Coatings
Baffle Shims
Coatings
Liner
Seals
Hystl 6793-132
Ashland
197/3 (T) (C)
Ashland
800 (T) (C)
Ashland 7240 (T) (C)
Ashland 72 (T) (C)
ATLAC 382 (T) (C)
ATLAC 711 m (C)
ATLAC 580 (T) (C)
Corralite 31-345 (T) (C)
Lower Casing - Walls
Viton
Hypalon (A)
Neoprene (A)
Upper Casing - Doors
Armalon
Teflon/Glass Fabric
Viton
Epo*y (A)
Alkyd (A)
Vinyl (A)
(continued)
-------
TABLE 19 (continued)
MATERIAL
EXCELLENT
GOOD
FAIR
Electrode Headers
Coatings
Sleeving
Seals
Vinyl Shrink Tubing
Viton "0" Rings
Epo*y (A)
POOR
Vinyl (A)
Alkyd (A)
Upper Casing (Hood)
Seal (Upper Casing Hood) Neoprene
i- Coati ngs
o
CO
Hypalon (A)
Neoprene (A)
Vinyl (A)
Alkyd (A) (T)
Upper Casing - Gas Stream
Metals
Ti (C.P.)
Ti - 0.2 Pd
Incoloy 825
Inconel 617
316 CRES
304 CRES (P)
Nickel (P)
Inconel 601 (I)
Ti - Code 12
Hastelloy C
(continued)
-------
TABLE 19 (continued)
MATERIAL
EXCELLENT
GOOD
FAIR |
POOR
Upper Casing - Gas Stream
Coatings
Teflon (A)
Polyphenylene
Sulfide (A)
Epoxy
Vinyl
Alkyd A) (T)
Key: (P) Pitting corrosion attack
(I) Intergranular corrosion attack
(A) Adhesion failure
Temperature induced attack
Chemical attack
i* i
(A)
(T)
(C)
-------
260
200
150
u
o
90
40
0
Jr
i
20 40 60 80
H2S04 CONCENTRATION, WEIGHT PERCENT
100
Figure 65. Boiling point of sulfuric acid in solution with water.
105
-------
c) The pH decreased from 7.96 to 2.43 to 2.53.
d) The specific conductivity at 25°C increased from 290 micromhos/
cm3 to 1200 to 1400 micromhos/cm3.
Equipment Life
As part of the materials evaluation task, the expected life of the exist-
ing 316 CRES unit is to be predicted. It must be understood that projecting
long term performance on data collected over a relatively short period is
risky. However, an attempt was made to project life making some assumptions
as to the type of inspection and maintenance which would be required.
The behavior of the 316 CRES alloy as tested can be summarized as uniform
corrosion rate ranging from 0.04 to 0.31 mmpy and a tendency to pit. The
measured pit depths on 316 coupons were of order of 5.0 x 10-5 which, 1f a
linear growth rate is assured, would result in pit growth rate of approximately
1 mmpy.
Two conditions must be considered; viz., (1) the thinning of the walls to
a point where the structure is unsound, and (2) the perforation of the wall by
local pitting causing gas flow disruption and emission of gas into the sur-
rounding area. The time to the first condition can be estimated from uniform
corrosion rate and the time for the second condition by a combination of
uniform corrosion rate and pitting corrosion rate. Thus:
T _ ti - ts
rc
T2 = V(rc + rp)
Where:
T, = time to reach minimum thickness required for strength (years)
T2 = time to perforate wall (years)
t = minimum thickness required for strength (mm)
t.j = initial casing wall thickness (mm)
r = uniform corrosion rate (mm per year)
r = pitting corrosion rate (mm per year)
The initial wall thickness is 4.8 mm and the value of ts is estimated as
2.0 mm. Assuming rc equal to 0.30 mmpy and rD equal to 1 mmpy, then:
TI = 9.3 years
T« = 3.6 years
106
-------
Typically pitting corrosion rates vary from point to point within a
structure and many samples are required to obtain a statistically meaningful
average. Since the CDS configuration is such that only a relatively small
number of coupons could be installed without disrupting the gas distribution
and the equipment performance, the 1 mmpy rate is highly suspect. Using
engineering judgment, it may be expected that some pits may grow two to three
times faster than the measured rates so that a value of T« closer to 2 years
would be more realistic.
Therefore, the anticipated behavior of the current structure is predicted
as follows assuming no change in the design or process:
• 0 to 2 years; Little or no maintenance required.
Periodic inspection recommended.
• 2 to 9 years: Local perforations in casing wall.
Inspect on a periodic basis. Repair by welding
doublers over perforated regions.
t 9 years: Some areas thinned to critical thickness.
Inspect. Repair or replace structure as necessary.
107
-------
SECTION 7
FLUE GAS STREAM CORROSIVES CONTROL
INTRODUCTION
The compound which is potentially the most corrosive in waste heat flue
gas is gaseous sulfur dioxide. In searching for a way to neutralize the
effects of the S02 and the resulting corrosion problem, it was determined that
the most effective method would be to inject an additive to react with the S02
and then have the resulting particulate collected by the CDS. After careful
analysis the Thermo-Chemical Mapping results, ammonia was chosen as the candi-
date additive.
Use of the CDS for gaseous S02 removal leads to several difficulties.
These difficulties can be eliminated by converting the S02 to a solid phase
prior to its entering the active cleaning volume of the CDS. This then allows
the full particulate removal capability of the CDS to be utilized for S02
removal.
The limitations to be considered with respect to using the CDS for
scrubbing gaseous phase S02 are:
(1) The CDS removal efficiency is limited by the gas phase surface
absorption and diffusion rates within the charged drops.
(2) The total material removal will always be limited by the
saturation solubility of S02 in the cleaning media.
(3) The outgoing waste water is acidic, thus creating potential
corrosion problems in the exhaust gas ducting and waste water
processing system.
The major task here was to determine if S02 could be reacted with moist
ammonia to form solid phase (NH4)2S04 within the CDS. A successful demon-
stration of the ability to achieve the desired S02 reaction would then
indicate the feasibility of using the CDS system for (NH4)2S04 particulate
collection.
CONCLUSIONS AND RECOMMENDATIONS
The NHa + S02 reaction can remove essentially all the S02 from a gas
stream with inlet concentrations of 500 ppm or less. A single CDS wet stage
has demonstrated removal efficiencies as high as 70 percent for the particulate
108
-------
reaction products at a velocity of 3.05 m/s (10 fps). Thus, a two-stage CDS
should achieve better than 90 percent removal, and a four-stage unit better
than 99 percent removal.
Without the NH3 additive and operating in the corona only mode, which is
essentially the operational mode for conventional electrostatic precipitators,
resulted in essentially zero S02 removal. There is a slight removal of the
corrosion causing S02 when the CDS is operated in the charged droplet mode.
APPROACH
The inlet gas stream consisted of ambient air mixed with 500 ppm reagent
grade S02. The experimental approach was to inject gaseous reagent grade
ammonia into the upstream inlet to the CDS.
Initially, it was thought that it would be necessary to add water vapor
and corona to accelerate the NH3/S02 reaction. The corona would assist the
reaction indirectly by creating ozone. The resultant reaction would be as
follows:
02 + Corona = 20""
o2 + o = o3
2(NH3) + S02 + H20 + 03 - (NH4)2S04 + 02 (1)
It should also be possible to get more direct action:
2(HN3) + S02 + H20 + 0"" = (NH4)2 S04 (2)
During the tests it was observed that the S02 could be removed via other
chemical reactions and without the need for a corona. This will be discussed
later in more detail.
Figure 66 is a schematic of the test apparatus. The CDS duct was operated
at a slightly negative pressure with the gas flow maintained by an exhaust
blower located downstream of the scrubber. The gas flowed vertically downward
through the CDS. An in-line damper was used to control the gas flow velocity.
The exhaust gas was vented into the building exhaust system.
The CDS could be operated in any one of three modes: single wet stage,
single dry corona stage or corona stage plus single wet stage. Gas injection
and sampling capabilities were proved by horizontal 9.5 mm (0.375 in.) diameter
perforated tubes extending across the duct inlet section. S02 concentrations
were measured at the scrubber outlet using an Environmetrics series N5-200
S02/N1trogen Oxide Analyzer. Ammonia injection rates were monitored with a
conventional rotameter.
An argon laser and an off-axis photodetector located at the exit of the
CDS cleaning section were used to observe particulate formation due to the
S02+NH3 reaction and removal due to CDS operation. The scattered Intensity
was displayed on a strip chart recorder connected to the photodetector output.
109
-------
SO2 INJECTOR
SAMPLING PROBE
NH3 INJECTOR
AIR IN (10 FPS)
CORONA STAGE (H.V.)
SAMPLING PROK
SCRUBBER STAGE (H.V.)
TO BUILDING EXHAUST
Figure 66. Experimental equipment arrangement.
110
-------
The detector output was assumed to be proportional to the particle
concentration at the CDS exit. Strictly speaking, this is only true if the
particle sizes remain constant for all conditions and if there is negligible
absorption in the scattering volume. However, the proportionality assumption
is valid for the present purpose of providing an initial feasibility
demonstration.
RESULTS AND DISCUSSIONS
Gas Phase S02 Removal
The purpose of the gas phase work was to provide a baseline set of pure
gas phase S02 CDS operational data for comparison with later measurements
with NH3 additive. Complete mixing of the S02 with the inlet air did not
occur until after the mixture had passed through the CDS. For this reason
efficiencies were based on the outlet sampling station readings where the
S02 concentrations were correlated with the inlet rotometer settings. The
removal efficiencies were calculated from the ratios of outlet concentrations
for the CDS on vs CDS off.
Table 20 summarizes the observations for the three CDS operating modes.
It can be seen that the S02 removal fractions were of the order of or less
than the probable errors in reading the total S02 concentration. The probable
error in these cases were estimated based on the reproducibility of the S02
analyzer readings over the time span of the measurements. Generally, any
given set of measurements would last on the order of one hour, the driving
factor being the approximately 20 minute equilibration time constant of the
analyzer.
Table 20 indicates a slight removal of S02 when the CDS operated in the
charged droplet mode. Operating the CDS in the corona only mode, which is
essentially the operational mode for conventional electrostatic precipitators,
resulted in essentially zero removal.
Since the major removal mechanism during normal CDS operation is S02
absorption through the surfaces of the charged droplets, it would be expected
that significant absorption also occurs on the wet collector plates. In order
to confirm this mechanism, downstream S02 concentrations were compared for wet
and dry collector plates with the CDS turned off for both cases. The results
are shown in Table 21.
It is apparent from Table 21 that S02 absorption into the wet surfaces
did occur. The magnitude of the observed effect was diminished by the fact
that significant drying occurred during the 20 minute equilibration time
required for the S02 analyzer.
Particle Formation Due to NH^ Injection
Ammonia was injected into the S02 laden gas stream to produce a range of
NHa molar concentrations varying from 1:5 to 4:1 corresponding to a range of
one-tenth to twice stoichiometry for reactions (1) and (2). The S02 inlet
111
-------
TABLE 20. CDS REMOVAL EFFICIENCY FOR GAS PHASE S02
(32 KV ELECTRODE VOLTAGE 3 m/s (10 fps)
GAS FLOW VELOCITY)
CONCENTRATION
RANGE
OPERATING MODE
CDS Off
Corona Only
Water Only
Corona + Water
LOW
so2
(ppm)
153 +10
147 ±10
127 +10
132 +10
EFF.
00
4
17
14
MEDIUM
so2
(ppm)
380 +60
383 +60
309 +60
325 +60
EFF.
(%)
3
19
14
HIGH
so2
(ppm)
786 +100
761 +100
736 +100
736 +100
EFF.
(%)
3
6
6
TABLE 21. S02 THROUGHPUT COMPARISON FOR WET AND DRY
COLLECTOR PLATES (CDS TURNED OFF, 3 m/s (10 fps)
DUCT FLOW VELOCITY)
SCRUBBER CONDITION
SOp Throughput (ppm)
DRY
427
WET
406
DRY
427
WET
412
DRY
427
concentration was 1000 ppm. The gas velocity was 3 m/s (10 fps). Relative
parti cul ate concentrations at the scrubber exit were measured by the laser
scattering system.
Figure 67 shows the scattered laser intensity as a function of NH3 con-
centration. The apparent particle concentration decreased sharply below
2.1 molar ratio and tended to level off above 1:1. This is in good agreement
with the 2:1 NHa to S02 ratio required for reaction.
S02 Removal By Reaction With NHq
was injected at molar ratios of 3.4:1, 1.7:1 and 1.2:1. In all three
cases there was a heavy parti cul ate fallout and the S02 concentration at the
outlet would fall below the sensitivity of the S02 detector (5 ppm) 1 percent
of the injected fraction. These measurements were carried out at nominal
112
-------
90
80
70
60
_j
Z
o
« 50
E
6
i/>
a
g 40
a.
on
9fl
10
.
y
f
/
/
/
/
\s
X
UGHT SCATTERING BY
PARTICLES AS FUNCTION
OF NH3: SOjMOLAR RATIOS
^~
/
'
•
.2 .4 .8 1 2 468
NHj: SO2 MOLAR RATIO
Figure 67. Particulate formation due to addition of NH-.
113
-------
500 ppm inlet S02 concentration. The virtual elimination of the S02 at even
the 1:1 molar ratio is surprising since this corresponds to 1/2 of stoichimetry
for the formation of (NHs^SO^ It is possible that S02 removal also occurred
via the following reactions:
2 SO- + 0, = 2 SO,
223 (3)
NH3 + H20 + S03 = (NH4) H S04
or
2 S0? + Op + 3 HN, -i- 2H90 = (NHj«SOA + (NHA) HSOA (4)
Ct O £ HfcH *t *f
These reactions would reduce the NHs required as compared with reactions
(1) and (2). Another factor is that the porous plug of the S02 detector had a
tendency to clog at the high particle concentrations that were created and
this may have caused the instrument to read erratically low.
The net observed effect may have been due to S02 precipitation through
reactions (3) and (4) coupled with clogging of the porous plug in the S02
analyzer.
It was possible to achieve better than 99 percent S02 removal even when
no corona was employed. This indicates that either the bisulphate reaction (3)
or the sulphate reaction (5) shown below occurred.
°2 + S°2 ' S03
SO, + H-0 = H,SO. (5)
O £ £ *T
H2S04 + 2 NH3 = (NH4)2S04
Figure 68 shows the scatter signal for various operating modes of the CDS.
For low molar ratios turning on either the corona stage only or water stage
only increased the particle concentration over that observed with the CDS.
Apparently the effect of the enhanced reaction rate due to the corona and
injected water was greater than that due to particle removal by the CDS.
Once the corona stage was on, turning on the water stage could decrease
the scattered signal appreciably, indicating net decreases of 30 to 70 percent
in the particle concentration. The true removal efficiencies were probably
higher. However, the experimental arrangement could not separate out the
effect of enhancing the primary chemical reaction. Since this effect would
always decrease the apparent removal efficiency, the highest efficiency
observed is best representative of the true CDS capability, i.e., 70 percent
removal per stage.
To summarize, it has been demonstrated that the HN3 - S02 reaction can
remove essentially all the S02 from an air duct with inlet concentrations in
the 500 ppm range. A single CDS wet stage has demonstrated removal
114
-------
VI
O
u
O
«/»
O
i
• CORONA ONLY
O WATER STAGE ONLY
O CORONA* WATER STAGE
MOLAR RATIO (NHgt
Figure 68. CDS parti oilate throughput for various operating
modes and different NH.^.-SOp molar ratios
, (3 m/s (10 fps) duct velocity, 500 ppm
S02 inlet)
115
-------
efficiencies as high as 70 percent for participate reaction products at
3 m/s (10 fps) duct velocity. Thus, a 2 stage CDS should achieve better
than 90 percent removal, and 4 stages better than 99 percent removal.
116
-------
SECTION 8
ELECTRICAL SPARK QUENCHING
INTRODUCTION
When the Charged Droplet Scrubber was operated in a coke oven waste
heat environment, some of the electrode nozzles were severely damaged during
a relatively short exposure period. Some of the damage could be attributed
to chemical attack, but the majority appeared to be the result of electrical
errosion.
The principles of operation of the Charged Droplet Scrubber dictate that
a direct current power source with minimum ripple be used to attain maximum
droplet generation efficiency. To attain the low ripple, the CDS utilized
high voltage filter capacitors. In addition, an R-C circuit is also required
to facilitate arc quenching. All this additional capacitance provides a
large energy reservoir which is discharged into each arc resulting in
excessive nozzle wear.
In an effort to improve arc detection and limit discharge energy levels,
an investigative program was initiated to explore alternative methods of
control. Figure 69 presents the Pre and Post investigation CDS sparks
sensing and electrical power configuration diagrams.
CONCLUSIONS
As the result of the investigative program, it has been concluded that:
1) The installation of a hard line spark sensing system which directly
detects sparks, manifested by abrupt changes in electrode voltage,
will significantly improve the reliability of the high voltage
control system.
2) The removal of the high voltage capacitors from the arc quench
R-C circuit will reduce the total energy available to an arc, but
at the cost of lower particulate collecting efficiency resulting
from a lower average electrode voltage. This reduction is caused
by the increased ripple.
3) Sustained arcs and hence nozzle damage can be reduced by modifica-
tions to the control system. The modification will extend that
power off-time that occurs in response to the control circuit
cut-back command from the spark sensing system. However, this
117
-------
00
UTILITY
POWER -
1 PHASE
HIGH VOLTAGE/
GROUND ISOLATION
1
AVC
FILTER ;L\
CAPACITOR]
INDUCTOR ^
Df-r
\^
•>
SPAR
DROPPING/ CAPACITOR ' -
STAGE ISOLATION DISCHARGE RESISTOR |
i i n '
1 ' i LJ i
-J- 1 ELECTRODE NO. 2
II ' '
1 i i , , , , , 1 1 i M 1 ,
1 *
Hi n §
i
JL STAGE . ELECTRODE NO. 1
~ 1 1
1 -i-
K CONTROL INPUT SIGNAL ,
PRE TEST CONFIGURATION
UTILITY
POWER
1 PHASE
HIGH VOLTAGE/
DROPPING/
GROUND ISOLATION
I
AVC
1 *
1 N
FILTER 4:
CAPACITOR]
INDUCTOR ^
D^r
vj
•)
STAGE ISOLATION
i k i
1 1
Hi
1
VOLTAGE .
DIVIDER I
SPARK CONTROL INPUT SIGNAL
»
» <
ELECTRODE NO. 1
M 1 M M I I 1 I M |
.1.
ELECTRODE NO. 2
• M M 1 M M M M I
COLLECTOR PLATE '
SPARK
PICKUP
COIL
POST TEST CONFIGURATION
Figure 69. Charged droplet scrubber spark sensing and electrical power diagram
-------
also tends to reduce particulate scrubbing efficiency, although to
a slight degree, because it reduces the overall on-time of the
system.
4) Individual high voltage power supplies and controls sets for each
stage will significantly increase system overall reliability and
performance. The individual supplies will permit each stage con-
troller to adjust the electrode voltage level for that stage
without effecting the others. This would tend to allow the stages
exposed to the high particulate concentrations to operate at a
lower voltage while permitting the downstream stages to operate
at their maximum voltage.
5). Although modification to the existing electrical power supply and
control design can improve reliability and performance, the
damaging effects of the filter capacitor discharge cannot be
totally eliminated unless the ripple can be reduced by a means
other than capacitance.
RECOMMENDATIONS
1) An alternate ripple control method should be investigated for the Charged
Droplet Scrubber application. The potential benefit would be an increase
in collection efficiency as the result of a higher average voltage and an
increase in equipment life.
2) Individual power sets should be provided for each electrode stage for the
purpose of improving system performance and reliability.
3) Replace the present design pickup coil type spark detection system with a
design which directly senses abrupt voltage changes (sparks) through a
voltage divider.
APPROACH
Spark Sensing
The approach taken to improve the reliability and durability of the spark
sensing system was to replace the magnetically coupled coil system with one
which was hardline coupled through a voltage divider. This system would have
two advantages; 1) it is hardlined and therefore not susceptible to spurious
electromagnetic influences, and 2) it can be placed in a location away from
the hostile environment of the flue gases.
Arc Quenching
The quenching of an arc is accomplished by inhibiting current flow to the
arc site. Therefore, it was postulated that this could be accomplished by
modifying the automatic voltage control unit (AVC) installed as original
equipment. Specifically, the Recovery Slope Control circuit would be modified
such that, the power off-time would be extended for a sufficient duration that
would allow the dissipation of the ionized gas surrounding the arc. If
119
-------
successful, this would allow the removal of the high voltage capacitors which
are presently utilized in the R-C arc quenching circuitry.
DESCRIPTION OF EXISTING SYSTEM
Spark Sensing System
The spark sensing system installed on the Charged Droplet Scrubber as
original equipment consisted of a three turn wire coil located within the
upper casing of the CDS and running parallel to the longitudinal axis of each
stage header, Figure 70. The coil of each stage is, in turn, connected in
series with the other stages and thereby provides a common signal to the spark
rate control system. The coil senses the sparking occurring within the gas
cleaning section of the equipment and provides a microvolt output. This sig-
nal, in turn, is amplified and used as the input to the automatic voltage
controller logic circuit.
In-service experience with the coil sensing system has uncovered two
significant drawbacks. Because of its antenna like characteristics it is
susceptible to spurious inputs and the location requirements necessitates
exposure to an extremely hostile environment with respect to temperature,
moisture and corrosives.
Arc Quenching Circuit
The automatic voltage control system controls the electrode voltage
using discrete input signals from the spark sensing system. However, if the
frequency of sparking is sufficiently high as to appear as a steady state
condition, the controller will only respond (cut-back) to the initial dis-
charge transient. Under a constant arc condition, the controller only pro-
vides a current limiting function. Therefore, an R-C circuit is utilized
to delay stage recharging, Figure 71.
This delay allows the column of ionized gas created by the arc to
dissipate and minimize the possibility of a low voltage reignition.
To minimize the resistance between the transformer and electrode and
still attain the necessary time constant, an additional 0.15 microfarad
capacitance was required. This additional capacitance had a devastating
effect on electrode nozzle wear and as a result severely impacted the equip-
ment maintenance requirements.
DISCUSSION
Spark Sensing
Rather than install additional circuitry between the high voltage elec-
trical compartment and the AVC, the existing voltage divider and associated
wiring which is currently used for monitoring stage voltages would be utilized
to carry the input signal to the spark sensing circuitry.
120
-------
STAGE
HEADER
STAGE
HEADER
THREE COILS IN SERIES
(3 TURNS EACH COIL)
SPARK
SENSING
AMPERE
Figure 70. Spark sensing coil
121
-------
STAGE
ISOLATION
RESISTOR
WATER
SUPPLY/HIGH
VOLTAGE
ISOLATION
TRANSFORMER/
RECTIFIER SET
VW-
HIGH
VOLTAGE
ELECTRODE
ARC
QUENCH
J_ FILTER ^CIRCUIT
T CAPACITOR
COLLECTOR
PLATE
1
TO
WATER
SUPPLY
Figure 71. CDS electrical power schematic-
122
-------
The signal conditioning circuitry consists of an audio amplifier, an
impedance matching transformer and a blocking diode, for each electrode stage,
Figure 72. Since the CDS system utilized in the development test program
incorporated a common high voltage power supply design for each two stages,
it is necessary that the controller responses to sparking on either or both
of the two stages. Therefore, the spark signal from each individual stage
must be fed in parallel, into the common controller logic circuit. For this
reason the blocking diodes are used to isolate the individual sensing circuits.
Two dual channel spark sensing systems were fabricated and installed on
the Charged Droplet Scrubber unit that was the subject of the redevelopment
program. The test instrumentation verified that the sensing system detected
all sparks and the control logic responded to all resulting input signals.
The system operated over a two month period without a failure.
Arc Quenching
Initially the capacitors of each electrode stage R-C circuit were removed
from the system. The change resulted in a drop of 4 KV in the average stage
voltage. In addition, the frequency of sustained (lock-on) arcs increased
substantially. Adjustment of existing Set-Back and Recovery-Slope controls
had little effect on the frequency of lock-on arcs. The reduction in the
average stage voltage was a result of a significant increase in the ripple
amplitude. Although there exists an 0.075 yf capacitor in parallel with the
transformer output specifically for filtering purposes, the capacitors
connected to each stage perform an additional filtering function. The stage
voltage ripple can possibly be reduced by increasing the high voltage filter
capacitance of the transformer output or by increasing the primary circuit
inductance.
The filter capacitance was increased to 0.15 yf. This resulted in a
2.5 KV increase in stage voltage. However, the energy discharged through the
arc is increased substantially since; the increase is directly proportioned
to the capacitance increase. The result would mean an increase in arc damage
rather than a decrease. In addition, this configuration tends to decrease the
stage-to-stage isolation. Although the stage isolation resistor is still in
the circuit, a spark in one stage causes the common filter capacitor to dis-
charge and thereby drop the supply voltage. The sustained arcing can be pre-
vented by modifying the controller logic, but at the cost of a substantial
increase stage off-time.
An alternate approach to lowering ripple was to increase the primary
impedance. The additional impedance would increase the thyrister firing angle
and result in a lower ripple and hence, allow a high average voltage to be
attained at the electrodes.
The impedance was increased by the addition of a 2 mH inductor. With
this addition, it was determined that the system was essentially inductance
current limited. The addition of 1 mH resulted in a 2 KV increase in stage
voltage. Table 22 presents a tabulation of the configurations tested and the
resulting electrical characteristics. Figure 73 presents photographs of the
resulting current and voltage waveforms.
123
-------
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-------
TABLE 22. CDS PRIMARY IMPEDANCE ADDITION TEST TABLE
TEST
NO.
1
2
3
4
5
6
7
AC
AMPS
55
104
106
106
106
106
50
VOLTS
275
263
281
281
298
308
312
DC
mAMPS
245
242
250
250
250
250
240
T-R KV
53
52.5
53
53
53.3
53.8
53
3N KV
32.5
32.5
32.5
32.5
32.5
32.5
32.5
4N KV
31.5
31.0
31.3
31.3
31.5
31.5
31.5
SPARKS
PER
MIN.
0
0
0
0
0
0
0
LEAKAGE
mAMPS
15.0
14.5
14.5
14.5
14.5
14.5
14.0
ADDED
PRIMARY
IMPEDANCE
IN MH
0
0
1
1
2
3
3
REMARKS
Photo #1, Note 2, Load
Bank off.
Photo #2, Note 1, Load
Bank on.
Photo #3, Load Bank on.
Photo #4, Notes 3&4, Load
Bank on.
Photo Nos 5, 6 & 7, Note 5,
Load Bank on.
Photo Nos 8&9, Note 6,
Load Bank on.
Photo Nos 10&11, Load Bank
off.
ro
NOTES:
(1) In 'auto' mode stage 2N is at 33.5 KV approx.
(2) System on old spark sensing coil for this test only.
(3) Added 4.8K resistor on T-R set KV bleed line to permit photographing T-R set KV waveform.
(4) In 'auto' mode stage 3N is 35.0 KV approx.
(5) Increased current limit setting on AVC unit circuit card A2. This had very little effect.
System was essentially current limited by primary inductance.
(6) Maximum voltage on stage 3N, in 'auto' and 'manual1 mode, 36.5 KV.
(7) System restored to original, standard condition, except sensing resistor on T-R Set bleed
line is left in.
-------
KV 'o', TY^3 (AJUeu, T-R
Figure 73. Oscilloscope photos of CDS primary
impedance addition test
126
-------
ran hi JS^6®" dete™1ned th^t the existing power supply and control design
°
of InLr rnn ,-° ^^/^P^ and present sustained arcs, but at the expense
arp nrnwiH i f Jffi"ency unless individual power supplies and controls
are provided for each stage.
127
-------
REFERENCES
1. Maddalone, R., and N. Garner. Process Measurement Procedures: Sulfuric
Acid Emissions. TRW Document No. 28055-6004-RU-01, May 1977.
2. Annual Book of ASTM Standards, Part 23. D-1193-70, Standard Specification
for Reagent Water. 1971, Pg. 196.
128
-------
APPENDIX A
ELECTRICAL TEST DATA
-------
TABLE A-l. KAISER CDS GAS TEST NON-UPSET CONDITION
TIME
11:15 AN
11:20
11:25
11:30
11:35
11:40
11:45
11:50
11:55
12:00 NOON
12:05 PM
12:10
12:15
12:20
NOTES:
INLET
TEMP
OF
-
-
370
373
353
355
358
363
367
371
351
353
357
TEST
361 ±8
OPACITY
X
17
7.5
6
5.75
14
12
10.5
10.5
10
12.5
5
5
^ 5
STOP
9.3i3.9
1-2
ACA
74
65
60
60
80
80
65
60
55
50
80
70
65
1-2
ACV
200
180
175
175
210
200
180
170
160
160
220
190
185
1-2
DCMA
145
125
105
110
160
150
115
105
100
100
170
140
120
KV
1
30
29.5
29
29
30.5
30.5
29
29
28
28
31
30
30
2
30
29.5
29
29
31
30.5
29
29
28
28
31
30
30
KV
TR
43
40
39.5
41
46
44
41
39
39
40
47
44
41
LEAK
HA
10
9.5
8.5
10
10
9.5
9
8.5
8.5
9
10
9.5
9
S/M
100-150
100-200
100-180
100-180
100-150
75-150
100-150
100-150
100-150
100-150
100-150
100-175
75-175
3-4
ACA
85
78
65
100
100
93
77
75
60
80
98
90
80
3-4
ACV
228
215
195
270
265
255
215
210
150
250
270
250
225
3-4
DCMA
180
155
108
210
215
190
160
150
100
210
215
200
165
KV
3
32.5
32.5
30
35
34
34
32.5
31
30
33
34.5
34
32.5
4
31.5
30.5
29
32
32
31.5
31
29.5
29
32.5
33
31.5
31
KV
TR
49
47
44
54
55
53
47
45
40.5
54
57
53
48
30.7il.8
LEAK
HA
11.5
12
10.5
13
13
12
11
10
10
13
13.5
12.5
11.5
S/H
100-200
100-180
75-250
100-200
100-225
100-200
100-200
100-200
100-175
100-175
100-225
150-250
100-225
REMARKS
NOTE 5
NOTE 6
NOTE 7
NOTE 8
1. System (Including hood) washed prior to start of test.
2. Sequencer relay TDR 1 pulled to keep system on electrically during light loud.
3. Oven 22 open at both ends throughout test. Oven Is relatively cool.
4. EEO time at outlet, plus 4 minutes, at Inlet, minus 2 minutes to that shown above.
5. Light white smoke from stack.
6. Stack clear-opacity jumped to 15* about time stages 344 were being read. About T+2 minutes.
7. Heavy sparking at door 7 on north side of north unit. Door 8 Is relatively cool both sides. Stack clear.
8. Inlet temperature had dropped to 360°F at 12:02 PM.
ABBREVIATIONS:
1-2: Stages 142: 3-4: Stages 3 & 4
ACA: Alternating Current Amperes
ACV: " Voltage
DCMA: Direct " Multl -Amperes
ro
vo
-------
TABLE A-2. KAISER CDS GAS TEST UPSET CONDITION
TIME
12:41:30 PM
12:46:30
12:51:30
12:56:30
01:01:30
01:05:15
01:06:30
01:11:30
01:16:30
OPACITY
% •
55
47
38
35
19
-
10
20
41
33±15
1-2
ACA
74
-
60
-
85
•
•
77
75
1-2
ACV
200
-
174
-
225
-
-
210
210
1-2
DCMA
175
-
60
-
180
-
-
150
150
KV
1
30
-
29
-
32
-
-
31
31
2
30
-
29
-
32
•
•
32
30
KV
TR
44
-
40
-
46
-
-
44
43
LEAK
MA
10
-
10
-
11.5
-
-
10.5
11
S/M
100-150
-
100-150
-
100-200
-
-
100-150
100-150
3-4
ACA
100
-
75
-
105
-
-
98
95
3-4
ACV
285
-
220
-
290
-
-
265
265
3-4
DCMA
240
-
160
-
260
-
• -
220
220
KV
3
35
-
33
-
35.5
-
•
35
34
4
33.5
-
31
-
34
-
-
33
32
KV
TR
53
-
44
-
58
-
-
54
53
LEAK
MA
14
-
12
-
15
-
-
14.5
14
S/M
100-250
-
100-200
-
100-200
-
-
100-200
100-200
REMARKS
NOTE 3
NOTE 3
NOTE 4
NOTE 5
NOTE 6
NOTE 7
01:20:00 TEST OFF STACK LIGHT GREY
NOTES:
1. Unit washed down prior to start of test.
2. EED time 1s 3.5 minutes ahead of tines noted above.
3. Grey oil plume.
4. Very little plume.
5. Off of "high" on opacity meter sequencer relay TOR 1 had been removed to keep unit on line.
6. Fan running time 1805.0 hours.
7. Brownish grey stack (partlculate).
ABBREVIATIONS:
1-2: Stages 1 & 2 : 3-4: Stages 3 ft 4
ACA: Alternating Current Amperes
ACV : " "
DCMA: Direct " Hultl -Amperes
u>
o •
-------
APPENDIX B
STATUS OF FLUE GAS CORROSION STUDY -
KAISER STEEL, FONTANA
-------
TOI37
t MO xmcf mjvus
• WOONOO MACM • CAUTOMMI «HT»
INTEROFFICE CORRESPONDENCE 5515.2.77-451
TO, R. Hession CC: OATK: November 1, 1977
Status of Flue Gas Corrosion Study - r«0M: L.A.Rosales/M.P.Bianchi
Kaiser Steel, Fontana. «ux» MA.LSTA. KT.
01 2220 52630
INTRODUCTION
The "Coke Oven Waste Heat Flue Gas Corrosion Study" is In-progress, see
Appendix. Subtask I is complete. Subtask II and IV are in-progress and some
preliminary work is being accomplished on Subtask III. A description of work
completed to date is included below.
SUBTASK I
Several candidate metallic and non-metallic materials, have been selected for
test in the Kaiser Steel North CDS unit. The metallic materials include 316 CRES
(the material of which the units are constructed), 304 CRES, titanium, and several
nickel-base superalloys. In addition, mild steel coupons were selected as a
substrate for candidate coating systems. The 304 CRES alloy was chosen as a
candidate since it is more sensitive to chloride pitting attack than 316 CRES and
would give an indication of excessive chloride build up in the system. The nickel
alloys were chosen for their resistance to sulfuric acid attack. Several alloys
were chosen for study which included various Cr-Mo-Fe compositions. Commercially
pure titanium is known to possess outstanding corrosion resistance to most media
and has performed well in sulfuric acid environments. It Is not affected by the
presence of chlorides. Two titanium alloys which possess outstanding crevice
corrosion resistance, Ti-0.2 Pd and Ti Code 12, were also included 1n the test.
Chemical lead, widely used in sulfuric acid applications, was also included for
test.
131
-------
Page 2
5515.2.77-451
Status of Flue Gas Corrosion Study
Kaiser Steel, Fontana
The non-metallic materials selected for test were chosen for their resistance
to chemical attack, temperature resistance, ease of application and fabrication,
as well as availability. The thermoset resins are the polyesters, an epoxy,
vinyl esters, and furans either in the form of fiberglass reinforced structural
composites or filled and unfilled coatings. The thermoplastic resins are
polyvinylchloride (PVC), alkyds, polyvinyllidene fluoride (KYNAR), polyphenylene
•sulfide, and teflon as coatings, shrink tubing, and a reinforced liner.
The elastomers are neoprene, Hypalon, and viton as coatings, liners, and seal
-and shims. The substrates for the liners and coatings are mild steel and 304 and
316 stainless steels.
-SUBTASK II
Two inch square coupons were made of all test materials. Some of these were
coated using the appropriate methods. In addition, some of the non-metallic
materials were fabricated into coupons by the suppliers. All coupons were coded
weighed and visual inspected prior to testing. The coupons were installed in
•the unit by hanging using 316 CRES wire or Teflon coated wire. The coupons
were situated in the west end of the hood and in the lower area under the baffles.
The type of coupons date of installation, location and remarks are presented in
Tables II and III.
Coatings were also applied to electrode headers, door panels and in the hood area.
The surfaces to be coated were prepared by solvent wiping with MEK. It should be
noted that it was very difficult to obtain clean surface due tr. access problems and
.the copious amounts of contaminating deposits and particulates in the atmospheres.
Therefore, the adhesion of the coatings to the substrate is not expected to be as
good as would be obtained under controlled conditions.
132
-------
TABLE B-l. TABULATION OF MATERIALS AND COATINGS SELECTED FQP TESTI'.G
A) Metals and Alloys
co
eo
Designation
1010 Mild Steel
304 CRES
316 CRES
A1 - 6X CRES
29-4 CRES
Ti 50 A
T1 - Code 12
Ti - 0.2 Pd
Haste Hoy C
Haste Hoy C276
Haste Hoy B
Haste Hoy X
Incoloy 825
Inconel 601
Inconel 617
Mickel
Chemical Lead
Composition
Fe - .QIC - 0.45 Mn
Fe - 18 Cr - 8 Ni - 1.5 Mn
Fe - 18 Cr - 8 NI - 3 Mo - 1.5 Mn
Fe - 20 Cr - 25 Ni - 6 Mo
Fe - 29 Cr - 4 Mo
C. P. Ti
Ti - 0.3 Mo - 0.8 Ni
Ti - 0.2 Pd
Ni - 15.5 Cr - 16 Mo - 5 Fe - 2.5 Co
Ni - 15.5 Cr - 16 Mo - 5.5 Fe - 3.7 W - 2.5 Co
Ni - 28 Mo - 2.5 Co - 1.0 Cr - 5 Fe
Ni - 22 Cr - 18 Fe - 9 Mo - 1.5 Co - .6 W
NI - 30 Fe - 21.5 Cr - 3 Mo - .9 Ti
Ni - 23 Cr - 14 Fe - 1.35 A1 - 0.5 Mn - 0.5 Cu
Ni - 22 Cr - 12.5 Co - 9.0 Mo - 1.0 Al - .07 C
Ni (pure)
Pb - 0.05 Cu - 0.005 Ag
Supplier
Allegheney
Allegheney
Timet
Timet
Timet
Huntington
Huntington
Huntington
Huntington
Huntington
Huntington
Huntington
Huntington
Ludlum
Ludlum
Alloys
Alloys
Alloys
Alloys
Alloys
Alloys
Alloys
Alloys
Code
S - ( )
304 - ( )
316 - ( )
Al - 6 - ( )
29 - 4 ( )
Ti - ( )
Ti - 12 - ( )
Ti - Pd - ( )
Hast. C - ( )
Hast. C276 - ( )
Hast. B - ( )
Hast. X - ( )
182D - ( )
1601 - ( )
1617 - ( )
Ni - ( )
Pb - ( )
-------
TABLE B-l (continued)
B) Non-Metallic Structural Panels
Designation
Composition
Atalc 302/Flex Bend 4010A Blsphenol Polyester FRP
Atlac 711-05A
Atlac 3U2-05A
Atlac 580-05A
Oerakane 470-45
Dcrakane 510-A-40
Polylite 33-402
CorraUte 31-345
7241-6
72L «• 5b-l
7240-4
137/3 + AT-8
800/801L-68
197/3-400
800 FR-10
tleoprene Elastomer
Viton Elastomer
Fire Resist. Polyester FRP
Blsphenol Polyester FRP
Blsphenol Vlnylester FRP
Vlnylester FRP
Vlnylester FRP
Polyester FRP
Polyester FRP
IPA Polyester FRP
Fire Retarded Polyester FRP
IPA Polyester FRP
Polyester FRP
Furan FRP
Pol tester FRP
Flame Retarded Furan FRP
Polychloroprene
Fluorocarbon
Supplier
ICI United States
ICI United States
ICI United States
ICI United States
Dow Chemical
Dow Chemical
Relchhold Chemical
Reichhold Chemical
Ashland
Ashland
Ashland
Ashland
Ashland
Ashland
Ashland
Gacoflex Western
Dupont
Code
AT382- ( )
AT711 - ( )
AT382/05 - ( )
AT530 - ( )
0470 - ( )
0510 - ( )
P33 - ( )
C31 - ( )
ASH7241 - ( )
ASH72L - ( )
ASH7240 • ( )
ASH197/3AT - ( )
ASH800 - ( )
ASH197/3 - ( )
ASH800FR - ( )
NB - ( )
V - ( )
-------
TABLE B-l (continued)
B) Non-Metallic Structural Panels
Designation Composition
Shrink Tubing - PVC Polyvlnylchlorlde
6793 Hystl Polybutadiene
Supplier
TRW
Code
ST- ( )
HY - ( )
01
C) Non Metallic Coatings
Designation
850-321/855-255
EA 919
Ryton
Compound W
960/659
Ceilcote 252
Kynar
N11R/N29 Neoprene
Hypalon Elastomer
4020
4030
4092
Composition
Polytetrafluoroethylene
Blsphenol-polyamlne cured epoxy
Polyphenylene sulflde
Vinyl Plastisol
Alkyd Resin
Glass Flake Filled Polyester
PolyvinlHdcne Fluoride
Polychloroprene
Polychlorosufonated Rubber
Filled Vlnylester
Filled Vlnylester
Filled Vinylester
Supplier Code
Dupon.t T
Hysol E
Phillips PS
TRW W
Rust-Oleum Corp. RO
Ceilcote C
Pennwalt K
Gacoflex Western N
Gacoflex Western H
Plasites 4020
Plasites 4030
Plasites 4092
-------
TABLE B-2. LOCATION OF TEST COUPONS IN UPPER CASING (HOOD)
Row
1 (North)
1 (North)
2 (Center)
2 (Center)
3 (South)
3 (South)
1
2
3
4
5
6
7
8
Location
1 (West)
2
3
4
5
6
7
8 (East)
1 (West)
2
3
4
5
6
7
8
9
10
11 (East)
(West)
Sample No.
304 - 2T
304 • 13W
304 - 8 PS
304 - 11 RO
304 - 4E
Haste Hoy C
1825 - 1
1601 - 3
Ti - Pd - 3
T1 - 12 - 3
316 -19
304- 24
Ni - 2
1617 - 2
T1 - 12
316 - 2T
316 - 15W
316 - 9 PS
316 - 10 RO
(Ea'st)
316
304
S
S
S
S
S
316
21
19
4E
12 RO
9 PS
5W
2T
5E
Date Installed
23 August 1977
.Remarks
23 August 1977
23 August 1977
23 August 1977
23 August 1977
23 August 1977
136
-------
TABLE B-3. LOCATION OF TEST COUPONS IN LOWER CASING
NOTE: Rows are numbered with 1 being the furthest West and increasing
numbers toward the East.
Locations of samples on a row are numbered with 1 being the furthest
North and increasing numbers toward the South.
Row
1
1
Location
1
2
Sample No.
S- ( ) C
S- 23K
Date Installed
10/6/77
10/6/77
Remarks
1
2
3
4
5
6
7
8
9
10
11
1
2
3
4
5
6
7
8
9
10
11
304-18
S - 14W
304 - 7PS
T1 - 12 - 1
T1 - Pd - 1
T1 - 1
304 - 17
HI - 5
304 - 10 RO
S - IT
304 - 16
316 -18
S - 13 RO
304 - 3T
1825 - 5
Ni - 1
316 - 17
1617 - 1
1601 - 2
316-13U
S - 8 PS
316 - 16
8/23/77
8/23/77
8/23/77
8/23/77
137
-------
TABLE B-3 (continued)
Row
4
5
5
6
Location
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
1
2
3
4
5
6
7
1
2
3
4
Sample No.
316 - 4E
316 - 12 RO
AT 382/05
AT 711 -1
AT 382 - 1
AT 580 - 1
316 - 7 PS
316 - 14W
316 - IT
ASH 7241 - 29
ASH 72L - 22
ASH 7240 - 39
ASH 197/3 AT - 5
ASH 800 - 25
ASH 197/3 - 5
ASH 800 PR - 20
ASH 800 FR - 21
ASH 197/3 -4
ASH 800 - 24
ASH 197/3 AT -6
ASH 7240 - 40
ASH 72L - 21
ASH 7241 - 30
HY - 180
HY - 132
P33-1
C31-1
Date Installed Remarks
8/23/77
8/23/77
8/29/77
2ltx'5" Coupe;
8/29/77
8/29/77
2*x5" Coupe
8/29/77
8/29/77
1/77
8/Z9/
8/29/
138
-------
TABLE B-3 (continued)
Row
8
8
Location
1
2
Sample Mo.
Pb - 2
Pb - 1
Date Installed Remarks
8/29/77
8/29/77
9
10
10
1
2
3
4
5
6
7
8
9
10
11
12
1
2
3
4
5
6
7
8
316 - ( ) NB
316 - ( )) NB
S - ( ) MB
S - ( ) NB
316 - 26N
316 - 25JJ
S - 18N
S - 17N
316 - 29H
316 - 28H
S - ( )H
S - ( )H
316 - 22
304 - 9 PS
T1 - 2
T1 Pd - 2
T1 - 12 - 2
316 - 11 RO
304 - IT
304 - 12
8/29/77
8/29/77
8/23/77
8/23/77
139
-------
TABLE B-3 (continued)
Row Location
11 1
2
3
4
5
6
7
8
" 9
11 10
12 1
2
3
4
5
6
7
8
9
12 10
13 1
4 2
1 3
13 4
14 1
14 2
15 1
16 1
17 1
Sample No.
304 - 16 RO
S - 5E
1601 - 4
1617 - 3
316 - 23
304 - 21
316 - 8 PS
1825 - 2
304 - 5E
S - 11 RO
304 - 20
S - 3T
Ni - 3
304 - 14W
316 - 6E
316 - 3T
S - 16W
304 - 15W
S - 10 PS
316 - 20
304 - 28K
Hast B - 1
Hast C - 1
S- ( ) C
S - 24K
304 - 29K
4092 - 1
4030 - 1
4020 - 1
Date Installed Remarks
8/23/77
'
8/23/77
8/23/77
.
8/23/77
10/6/77
,
10/6/77
10/6/77
10/6/77
9/13/77
9/13/77
9/13/77
140
-------
Page 3
5515.2.77-451
Status of Flue Gas Corrosion Study
Kaiser Steel, Fontana
The coatings applied were epoxy (Code E), vinyl (Code W) alkyd (Code RO),
neoprene (Code N) and Hypalon (Code H). In addition, an Armalon fabric
(TFE Teflon impregnated fiberglass) was applied to a door panel using epoxy
EA919 as an adhesive.
Hash couplings, located in the upper casing (hood), were coated with
epoxy, vinyl and alkyd and installed. Using the West to East numbering
system for plates and the North to South numbering system for nozzles, the
coated coupling locations are:
Plate Ho. Nozzle No. Coating Code
4 3 PS
4 8 PS
8 2 RO
8 4 RO
8 7 RO
12 1 W
12 4 W
12 7 W
18 1 E
18 3 E
18 7 E
The wash couplings were installed 8/23/77.
Header to electrode connectors were also coated and installed on the
North side of the unit on 8/23/77. Again, numbering the electrodes from
West to East, the location by stages (stage 1 at bottom, stage 4 at top) is:
Stage No. Electrode No. Coating Code
1 4 W
1 8 T
1 16 PS
2 4 PS
2 6 RO
2 8 E
2 16 W
2 20 RO
141
-------
Page 4
5515.2.77-451
Status of Flue Gas Corrosion Study
Kaiser Steel, Fontana
Stage No. Electrode No. Coating Code
3 4 E
3 8 PS
3 .16 T
3 20 RO
4 4 T
4 8 W
4 16 E
The first major examination of the test coupons is tentatively scheduled
for the week of 1 November 1977. Inspection of the door and header coatings
have been made with the following observations. The lower temperature coatings,
alkyd and vinyl, have blistered and discolored on the doors and some of the
headers. The epoxy is also showing extensive blistering and peeling in the
high temperature areas. The neoprene coating on the door has flaked off.
The Hypalon appears to be holding up as is the annaIon fabric. A detailed
examination of the wash couplings and electrode to header connectors has not
been made to date.
SUBTASK III
Thermo-chemical data has not been received by Materials Engineering as of
this date. Correlations with corrosion data will be attempted upon receipt
of the data.
Initial data on supply water and waste water chemistry has been received.
The data shov/s a chloride conteat much higher than found during earlier tests
(60 ppm vs 7 ppm). This has been attributed to a change In the domestic water
source (Kaiser now using Colorado River water). The data also shows that
approximately 35 ppm of chlorides are. being lost in the system (not appearing
1n th? waste water). If the chlorides are depositing in the scrubber, pitting
attack of the 316 CRES can be expected to occur. The report showed the pH of the
waste water to be approximately 2.5.
142
-------
Page 5
5515.2.77-451
Status of Flue Gas Corrosion Study
Kaiser Steel, Fontana
SUBTASK IV
Corrosion probe installation ports (3/4 NPT female ports) were installed
on the north side of the unit as shown in Figure 1. Five 316 CRES Magna
Corporation 21343/W40/8020 probes were installed in the ports on 13 September
1977. A sixth probe was found to be detective and was returned to Magna for
replacement. The probes were located as follows:
Probe 1 - Port A
Probe 2 - Port C
Probe 3 - Port D
Probe 4 - Port L
Probe 5 - Returned to Magna
Probe 6 - Port K
Five readings have been taken to date (on an approximate weekly basis).
Initial results indicate a very low general corrosion rate for the 316 CRES
elements. Results will be tabulated and correlated with coupon results.
Some problems with Probe 4 have been encountered during periods when the
unit 1s running. Magna says that electrical interference or high vibration
can produce the type of problems being encountered. Probe 4 1s located
near a junction box which has a fan cooling system.
143
-------
BAFFLES
t t t t
HOOD
AREA
1
DOOR
AREA
0L 0K
0
J
O
6
°H
- O
i
— CD
F
Or On
• n
0 0
Co
O
^ WEST
r^
r PERFORATED
PLATE 1
V
'~<<^
O
1
Figure B-l. Location of Corrosion Probe Ports Unit A
744
-------
APPENDIX C
WASTEWATER CHEMISTRY
-------
COKE OVEN WASTE HEAT FLUE GAS CORROSION STUDY
I. Statement of Objectives
The objective of the corrosion study is to identify materials of
construction which are resistant to corrosive attack in the Kaiser Steel
CDS environment. Metals and non-metals, including coatings and linings,
will be evaluated with special emphasis on those materials which not
only perform satisfactorily but are also practical from an economic
and fabrication viewpoint.
II. Task Breakdown
The corrosion study is broken into 5 subtasks as follows:
Subtask I. Using data obtained by analysis of CDS components,
literature, and TRW tests identify candidate materials for use
1n the scrubber. Consideration will be given to availability,
fabricability, and cost as well as corrosion, stress corrosion,
pitting and crevice corrosion resistance.
Subtask II. Prepare test coupons made of the candidate.materials.
Determine locations within the CDS and mount the coupons. Remove
and metallurgically and chemically analyze coupons at appropriate
time Intervals. Determine type of corrosive attack and the rate.
Subtask III. Using thermal mapping and electrical system data,
correlate corrosion data with the CDS operating modes. Special
emphasis will be placed upon determining differences in performance
due to differences in locations within the scrubber.
Subtask IV. Monitor instantaneous corrosion rate at selected
locations within the scrubber by use of an electronic corrosion
meter. Correlate meter data with test coupon data.
145
-------
TASK SCHEDULE AND MAN LOADING
I. Candidate Kat'l
Selection
-A
II. Specimen Preparation.
Test and Evaluation
IT1. Correlation of Data —
with Operating Cond.
IV. Electronic Corrosion.
Meter Data Collection
and Evaluation
V. Report Preparation
104 lira.
r-p
* Test Start
A A
A
,__ „
680 Hra.
A
140 Hra.
V
V
60 Hrs.
Basic
Manpower
Loading
(Man Hr/Wk)
ed
70
60
50
««0
30
20
10
n
—
„
I |
(D 1
— . . . 1 .
n
i
..
i .. . j ^
©
i — ' (V) i
0 1 '
n
1,1.
Weeks
-------
Subtask V. Prepare a final report which summarizes the corrosion
study. The report will describe the coupon materials and
configurations, test data, metallurgical and chemical analyses
procedures and data, and conclusions and recommendations.
The manpower and time required for each subtask is:
Subtask I 104 Hours 6 Weeks
Subtask II 680 " 22 "
Subtask III 140 " 15 •
Subtask IV 140 " 18 "
Subtask V 60 " 9 •
III. Approach
The approach to the determination of the compatibility of material in
the Kaiser CDS environment is to test in-situ and to evaluate by using
weight change data, visual inspection, metallographic examination, electron
mlcroprobe analysis and the scanning electron microscope. All data will
be correlated to specimen location within the scrubber and operating
conditions. The electronic corrosion meter data will be used to
-------
certified testing laboratories, inc.
2905 CAST CCKTl'HY OLVO. • SOUTH CATC. CALIf. 90C80 * (313) 064-2641
LABORATORY NO.
CLIENT
SAMPLE
62851
TRW
One Space Park
Redondo Beach, California 90278
V/ostewatcr (Kaiser)
REPORTED 10-7-77
SAMPLED
RECEIVED 10-4-77
MARKS
BASED ON SAMPLE
See Below
As Received
Results:
'6
Mickel
Chromium
Copper
30 II
ron (Total)
Ihloride
•'luoride
lyonlde
iulfire
•>ulfate
iulfide
>H (units)
{ardness (as CaCOo)
Specific Conductivity
P 25° C
micromhos/cm)
<0.03
<0.03
<0.02
<0.04
<0.05
60.1
0.19
0.02
<0.3
11.6
<0.10
7.96
82
290
0.31
0.70
<0.02
1.64
6.14
25.5
0.75
0.04
<0.3
286
<0.10
2.43
91
1310
0.13
0.47
<0.02
2.53
4.52
25.0
0.75
O.C6
<0.3
244
<0.10
2.50
91-
1250
0.19
0.33
<0.02
1.67
3.95
26.8
0.75
0.07
<0.3
236
<0.10
2.51
91
1210
0.16
0.33
<0.02
2.30
4.14
26.5
0.75
0.05
<0.3
242
O.10
2.51
91
1230
0.19
0.30
<0.02
1.68
3.48
25.8
0.75
0.04
<0.3
240
<0.10
2.52
91
1230
0.19
0.33
<0.02
1.86
3.48
25.5
0.75
0.12
<0.3
246
<0.10
2.50
91
1280
•|Mft • IT'';'*
10 ihr
. m not iu Ur'«»rJ. n. »l.olr i« in pjrl. n> jn>-
•••« »r I'uUJmy iiMiirc • iili.ntl rl»» »inun «uil...<. >.«;.», «t.».. .u,.. t . i .. :. ----- . _ . . _
148
-------
Pogc 2 of 3
certified testing laboratories, inc.
2905 CAST CCtUURY BLVD. • SOUTH CATC. CALIF. 90280 • (213) 5W-2C41
LAOORATORY NO.
CLIENT
SAMPLE
-42851
TRW
One Space Park
Redondo Beach, California 90278
Wastcwatcr (Kaiser)
REPORTED 10-7-77
SAMPLED
RECEIVED 10-4-77
MARKS
BASED ON SAMPLE
Results (Conf.)
Sse Below
As Received
Nickel
Chromium
Copper
Iron II
Iron (Total)
Chloride
Fluoride
Cyanide
Sulfite
Sulfare
Sutfidc
pH (units)
Hardness (as CaCOj)
Specific Conductivity
@ 25° C
(micromhos/cm)
1380
'10
'11
'12
'13
'14
0.22
0.38
<0.02
1.37
3.81
28.0
0.75
0.13
<0.3
280
<0.10
2.48
91
0.19
0.34
<0.02
1.44
4.05
28.3
0.75
0.15
<0.3
268
<0.10
2.46
91
0.25
0.47
<0.02
1.54
4.29
29.0
0.75
0.05
<0.3
256
<0.10
2.45
91
0.22
0.53
<0.02
1.41
4.05
27.5
0.75
0.12
<0.3
246
<0.10
2.47
91
0.25
0.56
<0.02
1.37
4.76
26.8
0.75
0.05
<0.3
240
<0.10
2.50
91
<0.03
<0.03
<0.02
<0.04
<0.05
59.8
0.19
0.03
<0.3
10.0
<0.10
7.96
82
0.16
0.34
<0.02
0.99
3.81
26.8
0.75
0.05
<0.3
220
<0.10
2.53
91
1440
1480
1420 1350
290
1210
ftnly 10 ihr «amPlr. «w
i |.f«»lurl%. A% * Milua
U^P M( idr rlii-nl in «l
rt. InvrMlr.jIr.l aurf i« nn( nrcrtsafilx inJJc»li»r «•« iliC i|
rr li.Mt i.. . lirnls. ilir |-il.li( jn.l ilir»r l.jl..unn.r\. llu\ i
i% ••Mrr\tr%l tnJ u|»«i ilic con.liiinri ihji it it, u*i in In-
... — .1. _:...:._ t. .— •• ..... • .....
149
. m »h«lr m in pjn. n»
-------
Page 3 of 3
certified testing laboratories, inc.
2901 CAST CCNTURY OLVD. - SOUTH CATC CALIf. 90280 • (213) 564-JG41
. LAOORATORY NO.
CLIENT
SAMPLE
62853
TRW
One Space Perk
Redondo Beach, California
Wastewoter (Kaiser)
90278
REPORTED
SAMPLED
RECEIVED
10-7-77
10-4-77
MARKS
BASED ON SAMPLE
Results (Conf >
See Below
As Received
Nickel
Chromium
Copper
Iron II
Iron (Total)
Chloride
Fluoride
Cyanide
Sulfite
Sol fate
Sulfide
pH (units)
Hardness (as
Specific Conductivity @ 25° C
( micromhos/cm)
'15
'16
'17
'18
1180
1220
1290 1380
'19
0.13
0.25
<0.02
1.86
3.10
25.5
0.75
0.05
<0.3
216
<0.10
2.56
91
0.13
0.28
(ily in.lic>li»« ttl the
|4i>lrcliim m t lirnfs. I In- i ul.lii jn.l il.rsc I jt«>t^liillr\. lUi\
;. .. ..1.1. ...^.J ...I Mn ,^..t.~. ._ i.._. .1 ..;.;. ~ ...->-
150
at rxnililiiMl <•(
-------
certified testing laboratories, inc.
2905 CAST CCNTURY OLVO. • SOUTH GATE. CALIF. 90730 • (213) SS4-2G41
LABORATORY HO.
CLIENT
"62351 - Supplement
TRW
One Space Pork
Redondo Beach, California 90278
REPORTED
10-12-77
Analytical Methods Used in Water Analysis;
All samples were filtered through 0.45 micron A/iillipore filters. Methods used v/cre those dss-
cribed in Federal Register, 41, No. 232, 1976, v/hen applicable.
Nickel
Chromium
Copper
Iron (Total)
Chlorides
Fluoride
Cyanide
Sulfite
Sulfate
Sulfide
PH
Hardness
Specific Conductivity
Iron II
Atomic Absorption
Atomic Absorption
Atomic Absorption
Atomic Absorption
Titration with /v'srcuric Nitrate
Ion Selective Electrode*
Pyridine - Barbituric Acid*
Titrimetric- Iodine
Turbidi metric
Photometric - Methylene Blue
Electronic trie
Sum of Co, Mg & Fe by AAS
Wlieotstone Bridge Ccnc'uctiinehy
Photometric - 1,10 Phenanthrolins
"Sample not distilled due to lack of sufficient sample.
Respectfully sub,-
CERTIFIED
ORIES, INC.
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-------
KSC Water Samples
03 October 1977
NOTE: 30 Second time period to pull one sample with vacuum pump
Sc-ole No.
1
2
3
4
5
6
7
5 8
5
10
11
12
13
14
15
16
17
18
19
Time
2:20
3:10
3:15
3:20
3:23
3:25
3:27
3:29
3:31
3:33
3:34
3:37
3:57
3:40
3:43
3:49
3:53
3:56
4:00
Location
HgO Input
COS Disch.
ii
n
"
n
n
n
Domestic
Water
COS Disch.
Process Conditions
Domestic Kater
Battery in Steady State •- No Upset •- Before- Pushing
First Oven Pushed — Started Sample at Ram Retraction
Oven Pushed but not yet charged
Start of Charging Operation
Charging In process
Charging completed, slight stack emission - beginning
Upset '
Upset
Start of pushing operation on second oven
One minute after start of -push
One minute after Ram retracted
Charging Vent Closed on Second Oven Pushed
Upset Continues — 5 Minute Sample Time (3:43 Start,
High Spark Rate in Unit - Heavy Upset
One Minute after Ram retracted on Third Oven Pushed
Upset Continues
End of Battery Activity — Stack Looks Good • Slight
Begins
plus one minute
of upset
3:48 Complete)
Steam Plume
-------
/»/ TECHNICAL REPORT DATA
friease read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/7-79-017
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
TRW Charged Droplet Scrubber Corrosion Studies
5. REPORT DATE
January 1979
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Frederick A. Whitson
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
TRW, Energy Systems Group
One Space Park
Redondo Beach, California 90278
10. PROGRAM ELEMENT NO.
EHE624
11. CONTRACT/GRANT NO.
68-02-2613, Task 7
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
Task Final; 8/77 - 10/78
14. SPONSORING AGENCY CODE
EPA/600/13
Harmon' MaU
» 919/
16. ABSTRACT
The report gives results of corrosion studies to provide definitive data
concerning the corrosive nature of coke-oven waste-heat flue gas and its effects on
wet electrostatic precipitators, and specifically on TRW's Charged Droplet Scrub-
ber (CDS). The study characterized the chemical composition of the waste heat flue
gases; related these data to corrosion and to the effects on the electrostatic scrub-
bing mechanism; evaluated materials compatibility with the coking process waste
heat environment; and identified candidate agents which may be introduced into the
waste heat gas stream to minimize the corrosive effects. It was determined that,
with several equipment and operating modifications, projected life of the CDS casing
and internals is 5 to 10 years, and life expectancy of the electrode nozzles is 1 to 2
years.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Air Pollution
Coking
Flue Gases
Gas Scrubbing
Drops
Electrostatic Precipitators
Corrosion
Charged Particles
Air Pollution Control
Stationary Sources
Charged Droplet Scrub-
ber
Waste Heat
Wet Scrubbers
13B
13H
21B
07A
07D
131
20H
8. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (ThisReport)
Unclassified
21. NO. OF PAGES
153
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
153
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