EPA-650/2-75-057-g
September 1975
Environmental Protection Technology Series
OF FLUE GAS
DESULFURIZATION SYSTEMS
DICKERSON STATION, POTOMAC ELECTRIC POWER CO.
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EPA-650/2-75-057-g
SURVEY
OF FLUE GAS
DESULFURIZATION SYSTEMS
DICKERSON STATION, POTOMAC ELECTRIC POWER CO.
by
Gerald A. Isaacs
PEDCo-Environmental Specialists, Inc.
Suite 13
Atkinson Square
Cincinnati, Ohio 45246
Contract No. 68-02-1321, Task 6g
ROAP No. 21ACX-130
Program Element No. LAB013
EPA Project Officer: Norman Kaplan
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, North Carolina 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, D. C. 20460
September 1975
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EPA REVIEW NOTICE
This report has been reviewed by the U.S. Environmental Protection
Agency and approved for publication. Approval does not signify that
the contents necessarily reflect the views and policies of the Environ-
mental Protection Agency, nor does mention of trade names or commer-
cial products constitute endorsement or recommendation for use.
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environ-
mental Protection Agency, have been grouped into series. These broad
categories were established to facilitate- further development and applica-
tion of environmental technology. Elimination of traditional grouping was
consciously planned to foster technology transfer and maximum interface
in related fields. These series are:
1. ENVIRONMENTAL HEALTH EFFECTS RESEARCH
2. ENVIRONMENTAL PROTECTION TECHNOLOGY
3. ECOLOGICAL RESEARCH
4. ENVIRONMENTAL MONITORING
5. SOCIOECONOMIC ENVIRONMENTAL STUDIES
6. SCIENTIFIC AND TECHNICAL ASSESSMENT REPORTS
9. MISCELLANEOUS
This report has been assigned to the ENVIRONMENTAL PROTECTION
TECHNOLOGY series. This series describes research performed to
develop and demonstrate instrumentation, equipment and methodology
to repair or prevent environmental degradation from point and non-
point sources of pollution. This work provides the new or improved
technology required for the control and treatment of pollution sources
to meet environmental quality standards.
This document is available to the public for sale through the National
Technical Information Service, Springfield, Virginia 22161.
Publication No. EPA-650/2-75-057-g
11
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ACKNOWLEDGMENT
This report was prepared under the direction of Mr.
Timothy W. Devitt. The principal author was Dr. Gerald A.
Isaacs. Mr. Charles D. Fleming was responsible for edi-
torial review and preparation of graphic materials.
Mr. Wade H. Ponder, former EPA Project Officer, had
primary responsibility within EPA for this project report.
Information and data on the plant operations were supplied
by Mr. D. A. Erdman, Potomac Electric Power Company, and by
Mr. John D. Lagakos, Chemico Air Pollution Control Company
during and subsequent to the plant survey visit.
The author appreciates the efforts and cooperation of
everyone who participated in the preparation of this report,
111
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TABLE OF CONTENTS
Page
ACKNOWLEDGMENT iii
LIST OF FIGURES V
LIST OF TABLES V
SUMMARY vi
1.0 INTRODUCTION 1-1
2.0 FACILITY DESCRIPTION 2-1
3.0 FLUE GAS DESULFURIZATION SYSTEM 3-1
3.1 Process Description 3-1
3.1.1 Ash Removal 3-1
3.1.2 SO2 Absorption 3-3
3.1.3 Solids Concentration 3-4
3.1.4 Drying 3-4
3.1.5 Dry Solids Storage 3-5
3.1.6 Calcination 3-5
3.2 Process Control 3-8
3.3 Installation Schedule 3-9
3.4 Cost Data 3-9
4.0 FGD SYSTEM PERFORMANCE 4-1
4.1 Start-up Problems and Solutions 4-1
4.2 Performance Test Run 4-5
4.3 Performance Parameters 4-6
4.4 Process Modifications and Economics for 4-6
Future Installations
APPENDIX A PLANT SURVEY FORM A-l
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LIST OF FIGURES
Figure
2.1
3.1
3.2
3.3
FGD Gas Flow Schematic - Dickerson No. 3 -
PEPCO
General Flow Diagram of the FGD System on
Dickerson No. 3 - PEPCO
Calcining System Process Flow Diagram at
Essex Chemical Co. - Rumford, R.I.
Sulfuric Acid Plant - Process Flow Diagram
at Essex Chemical Co. - Rumford, R.I.
Page
2-2
3-2
3-6
3-7
Table
2.1
4.1
LIST OF TABLES
Pertinent Data On Plant Design, Operation
and Atmospheric Emissions
Availability Calculations - Dickerson No. 3
FGD System - PEPCO - 1974
Page
2-3
4-7
VI
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SUMMARY
A flue gas desulfurization (FGD) system utilizing the
Chemico-Basic MgO-SO2 removal/recovery process has been
retrofitted to handle approximately one-half the exhaust gas
from the 190 MW Unit 3 at the Dickerson Station of Potomac
Electric Power Company. The dry-bottom, pulverized-coal-
fired boiler, designed and installed by Combustion Engi-
neering in 1962, is equipped with a Research-Cottrell
electrostatic precipitator that operates with an estimated
particulate collection efficiency of 94 percent. Coal burned
at the station has an average gross heating value of 11,700
BTU/lb, an ash content of 14 percent, and a sulfur content
of 2 percent.
A single, two-stage scrubber/absorber is used. The
first stage (scrubber) incorporates an adjustable venturi
for particulate removal, and the second stage (absorber)
uses a fixed venturi configuration to remove sulfur dioxide.
The liquor streams for the two stages are separate and
independent. Both streams are operated in a closed-loop
mode. Magnesium oxide (MgO) is regenerated using an EPA
financed facility at the Essex Chemical Company sulfuric
VII
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acid manufacturing plant in Rumford, Rhode Island, where by-
product SO2 from the regeneration process is converted to a
sulfuric acid. Excessive transportation costs for this
particular prototype demonstration project are incurred in
shipping magnesium compounds back and forth between Maryland
and Rhode Island. The Rhode Island acid plant was used
because it was available and was of proper size for the
demonstration program.
The system was started up in September 1973 and was
operated intermittently for shakedown purposes until January
1974. The system was then shut down because the Rumford
facility was at that time still being used for a desul-
furization project with Boston Edison. The longest con-
tinuous run during the first phase of operation was 271
hours. The system was restarted in July 1974 and operated
until January 1975. The boiler was shut down for a major
turbine overhaul from January 28, 1975 through August 11,
1975. The FGD system started up on August 11, 1975, and is
anticipated to run for 3 to 4 weeks. Operation is limited
by the MgO on hand at Dickerson, since the Essex facility
has been shut down. Particulate and SO2 removal efficiency
guarantees have been demonstrated. Pipe and pump corrosion
problems have frequently caused FGD unit outages. This is
attributed mainly to improper material selection (mild
steel) for the second stage recirculation system. Rubber-
lined pumps and piping have been suggested to minimize these
problems.
Vlll
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The FGD system was installed at a cost of $6.5 million.
This cost does not include substantial engineering and
development costs incurred by Chemico and Potomac Electric
Power Company, nor does it include the cost of MgO regen-
erating facilities. A station transformer spare was used to
power the FGD system in order to avoid an additional ex-
penditure of $200,000 to $500,000 for a separate substation.
The Dickerson Station is presently operating under a
variance from the State of Maryland. Additional installa-
tion of desulfurization equipment at this station is con-
tingent on further evaluation of the system to be initiated
around mid-1975. Operation of the FGD system will be in-
definitely terminated at the conclusion of this evaluation
since the Essex facility has been permanently shut down.
Pertinent operational data are summarized in the
following table.
IX
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SUMMARY OF PERTINENT FGD DATA
FGD unit rating
Fuel characteristics
FGD system supplier
Process
New or retrofit
Start-up date
FGD modules
Efficiency,
Particulate
so2
Make-up water
Unit cost
95 MW (net)
Coal; 11,700 BTU/lb, 14% ash, 2% S
Chemico
Magnesium oxide
Retrofit
September 1973
One
99.3%
90%
3.2 gpm/MW
Capital estimate: $6.5 million
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1.0 INTRODUCTION
The Industrial Environmental Research Laboratory
(formerly Control Systems Laboratory) of the U.S. Environ-
mental Protection Agency (EPA) has initiated a study to
evaluate the performance characteristics and degree of
reliability of FGD systems on coal-fired utility boilers in
the United States. This report on the Dickerson Station of
Potomac Electric Power Company (PEPCO) is one of a series of
reports on such systems. It presents values of key process
design and operating parameters, describes the major start-
up and operational problems encountered at the facility and
the measures taken to alleviate such problems, and identifies
the total installed and annualized operating costs.
This report is based upon information obtained during
a plant inspection on February 11, 1975 and on data provided
by PEPCO and Chemico personnel.
Section 2.0 presents pertinent data on facility design
and operation including actual and allowable particulate and
SO_ emission rates. Section 3.0 describes the FGD system,
and Section 4.0 analyzes FGD system performance.
1-1
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2.0 FACILITY DESCRIPTION
The Dickerson Station of PEPCO is located on the Potomac
River outside the town of Dickerson, Maryland. The plant is
situated in a rural, nonindustrialized area about 30 miles
northwest of Washington, D. C. Coal is delivered to the
plant by rail.
The station has three electric generators each rated at
190 MW. A fourth generator, rated at 800 MW is scheduled
for installation nearby by 1982. The installed 95 MW FGD
system is sized to handle approximately one-half the exhaust
gas flow from Unit No. 3.
Unit No. 3 has a dry-bottom coal-fired boiler that was
designed by Combustion Engineering and installed in 1962.
The coal presently burned has an average gross heating
value of 11,700 BTU/lb. Average ash and sulfur contents are
14 percent and 2 percent, respectively.
The boiler is fitted with an electrostatic precipitator
(ESP) designed and installed by Research-Cottrell in 1962.
Particulate collection efficiency is estimated to be 94
percent. The FGD system is installed so that it can receive
exhaust gas either from the outlet or from the breeching
ahead of the ESP. Figure 2.1 is a gas-flow schematic for
this installation. Table 2.1 gives pertinent data on plant
design, operation and atmospheric emissions.
2-1
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STACK
BOILER
SCRUBBER
FAN
Figure 2.1 FGD gas flow schematic
Dickerson No. 3 - PEPCO.
2-2
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Table 2.1 PERTINENT DATA ON PLANT DESIGN, OPERATION
AND ATMOSPHERIC EMISSIONS
Boiler data - Dickerson No. 3 - PEPCO
Rated generating capacity, MW
Average capacity factor (1974), %
Boiler manufacturer
Year placed in service
Unit heat rate, BTU/KWH
Maximum coal consumption, ton/hr
Maximum heat input, MM BTU/hr
Stack height above grade, ft
Flue gas rate - maximum, acfm
Flue gas temperature, °F
Emission controls:
Particulate
S02
Particulate emission rates:
Allowable, gr/scf
Actual, gr/scf
SO- emission rates:
Allowable, Ib/MM BTU
Actual, Ib/MM BTU
190
81
Combustion Engineering
1962
9180
74.5
1744
400
590,000
259
ESP and venturi
scrubber
Venturi - absorber
on half of the
gas flow
0.03
0.02
1.6a
0.3b
a 1% sulfur coal equivalent.
Based on 2 percent sulfur in coal, 95 percent conversion of
sulfur to SO2 and 90 percent FGD efficiency.
2-3
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3.0 FLUE GAS DESULFURIZATION SYSTEM
3.1 PROCESS DESCRIPTION3
Figure 3.1 is a schematic flow diagram for the Chemico-
Basic FGD system installed to handle approximately one-half
(295,00 acfm at 259°F) of the exhaust gas from Unit 3 of the
Dickerson Station of PEPCO. The maximum gross continuous
generating capacity for the unit is 190 MW. The boiler was
manufactured by Combustion Engineering, Inc., and was placed
in service in 1962. The generator, a base load unit, operated
with an 81 percent capacity factor in 1974. The FGD system
incorporates six major processing steps, i.e., 1) ash re-
moval, 2) SO- absorption, 3) solids concentration, 4) dry-
ing, 5) dry solids storage, and 6) calcination. Only the
first five steps are accomplished on-site at the Dickerson
facility.
3.1.1 Ash Removal
A two-stage scrubber/absorber is used at this plant.
The first stage is an adjustable throat venturi where the
gas is cooled from 250°F to 120°F and saturated. This stage
is used for fly ash (particulate) control only, and recir-
a Adapted from "Chemico-Basic Magnesium Based SO2 Recovery
Scrubbing Systems," by P.M. Wechselblatt and Robert H.
Quig - Presented at AIChE 71st National Meeting, Dallas,
Texas, February 20-23, 1972, and supplemented with data
from field visit.
3-1
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TW STAGE
SCRUBBER
UJ
I
to
FLUE GASES
HOTHER XORIER FEED CONVEYOR
LIQUOR TANK
NgSOj CONVEYOR
&=» Ngso, Kim ftaa
Figure 3.1 General flow diagram of the FGD system
on Dickerson No. 3 - PEPCO.
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culating streams for the two stages are separate and in-
dependent. Ash-laden water is circulated at a two percent
solids concentration. The adjustable venturi automatically
controls the first stage pressure drop at 11 in. H^O.
Overall design system particulate collection efficiency is
99 percent. Actual efficiency was measured to be 99.3
percent when the ESP was bypassed. The ESP was designed to
attain 97.5 percent efficiency, but it attains only about 94
percent efficiency, burning coal containing 2 percent sulfur.
A 980 gpm bleed stream from the recycle line carries
ash to the thickeners. A flocculant is used to aid settling
in the thickeners. Thickener underflow, 20 gpm at 40 per-
cent solids, is discharged to a dilution tank where water is
added, and the mixture is pumped to a settling pond, The
overflow cascades through a total of four ponds in series,
and the water from the lowest pond is then pumped back to
the dilution tank. The thickener overflow is pumped back
into the first stage of the scrubber so that closed-loop
operation is maintained.
3.1.2 SO^ Absorption
The flue gas leaves the first stage passing upward
through an annular mist eliminator and then downward through
the second stage of the scrubber which is designed to remove
90 percent of the S02 from the flue gas stream. The S02 gas
diffuses into the surface of the water droplets and chemically
reacts with the MgO forming hydrated magnesium sulfites.
Some MgSO4 is also formed as a result of the reaction of SO.
3-3
-------
with MgO and as a result of the oxidation of MgSO-. The
slurry solids have a relative composition of 89.6 percent
MgSO3-6 H2O and MgS03 • 3 H2O (MgSO.j-6 H2O predominantly), 5.0
percent MgS04«7 H20, and 5.4 percent MgO.
MgO + S02 + 6 H20 - - MgSO.j-6 H2O
MgO + S02 + 3 H20 - - MgSO.j-3
Other reactions that occur are:
MgO + SO + 7 HO - - MgSO • 7
MgS03 + 1/2 02 + 7 H2O - - MgSO4 - 7 H2O
The flue gas and entrained liquor then enter the separator
portion of the absorber through a central downcomer. The
liquor falls to the lower section of the separator which
serves as an integral storage reservoir while the gas
containing less than 150 ppm SO2 passes upward through the
second stage mist eliminators and is exhausted through the
stack to the atmosphere.
3.1.3 Solids Concentration
A 170 gpm bleed from the absorption system enters a 36
in. x 72 in. solid-bowl centrifuge where the crystals of
MgSO_-6 H2O, MgSO_-3 H20 and MgSO^-7 H2O and unreacted MgO
are separated from the mother liquor. The mother liquor is
returned to the absorption system and the centrifuged wet
cake enters the dryer.
3.1.4 Drying
The wet cake containing MgSO_-6 H2O, MgSO_-3 H2O,
MgSO.-7 H2O, MgO and surface moisture is dried by direct-
firing to remove surface and bound moisture. Dry solids
3-4
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total about 100 Ib/min. The drying reactions are as fol-
lows :
MgS03-6 H20 Heat^ MgS03 + 6 H2O (g)
MgS03-3 H20 Heat^ MgSO3 + 3 H2O (g)
MgS04-7 H2O Heatr MgSO4 + 3 H2O (g)
H2O (1) Heat^ H20 (g)
Exhaust gas from the dryer passes through a cyclone dust
collector and back into the second stage of the scrubber.
3.1.5 Dry Solids Storage
The anhydrous MgS03 and MgSO. material is conveyed from
the dryer to a storage silo where it is kept until it is
transported by covered trucks, barges or rail cars to the
sulfuric acid manufacturing plant. Regenerated MgO is
returned (with make-up) and stored in an MgO silo at the
power plant. The MgO slurry is prepared using regenerated
MgO, make-up MgO and mother liquor. The MgO slurry is added
as make-up to the absorption recycle liquid system. The
MgS03 storage silo has a design capacity of 200 tons (7
days). The MgO storage silo has a design capacity of 100
tons (7 days).
3.1.6 Calcination
Figures 3.2 and 3.3 show the schematic process flow
sheets of the calciner plant and sulfuric acid plant. Both
processes are external to the Dickerson Station. The dry
crystals of MgS03, MgS04 and MgO are received, weighed, and
conveyed to the MgS03 silo. The crystals are fed from there
to the direct-fired rotary calciner at a metered rate and
3-5
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co
I
n
CONVEYER
TO SULFURIC
ACID PLANT
CONVEYER
CONVEYER^ |
ELEVATOR
Figure 3.2 Calcining system process flow diagram at Essex Chemical Company
Rumford, Rhode Island.
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so? IK FLii^cAS
FROM CALCINER
UJ
COLU HEAT
EXCHANGER
981.
PUMP
TANK
COdlERS
i ACIO
CIRCULATING
PUMP
98~.
PUMP
TALK
98Z
CIRCULATING
PUMP
981 PRODI.'.'!
ACIO TO
STORAGE
NO FLOW WHFN
MARKING 93i ACIO
Figure 3.3 Sulfuric acid plant - process flow diagram
At Essex Chemical Company, Rumford, Rhode Island.
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calcined to generate SO2 gas and regenerate MgO. Coke is
added to reduce the residual MgSO4 to MgO and SO2. The
reactions are:
MgSO3 Heatr MgO + SO2
MgS04 + 1/2 C Heatr MgO + SO2 + 1/2 CO2
The calciner effluent gas containing 7 - in percent SO_ and
the MgO dust enter a hot cyclone where essentially all of
the dust is collected and returned to the calciner. The gas
then enters a venturi scrubber, where final dust cleaning is
accomplished and the gas is adiabatically saturated. The
saturated gas is cooled to 100°F in a direct contact cooler.
The cleaned, cooled gas enters the drying tower and the
sulfuric acid plant for production of 98 percent sulfuric
acid. Alternately, the gas can be reduced to elemental
sulfur. The regenerated MgO is cooled, conveyed to the MgO
storage silo, and recycled back to the power plant site for
reuse.
3.2 PROCESS CONTROL
The control process for this FGD system is relatively
simple. Basically, the liquid flow rates through the scrubber
are constant and independent of gas load. The first stage
of the venturi is automatically adjusted to maintain an 11
in. H20 pressure drop across the venturi. MgO additive feed
rate is varied to maintain the slurry pH at a preset point,
about 7. The pH is measured at the discharge of the second
stage recirculation pump. A downward pH movement triggers
3-8
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the addition of MgO to the system from the MgO make-up tank.
The control system has been found to be reliable and relatively
trouble-free.
3.3 INSTALLATION SCHEDULE
This system was designed by Chemico who also performed
the architectural and engineering work. Construction work
was performed by Brown & Root, Inc. On-site construction
began July 1972, and was completed in September 1973. Plant
start-up occurred in September 1973, but shakedown tests
were not completed until July 1974. The long interval
between start-up and shakedown occurred because the calcina-
tion facility at Rumford, Rhode Island was unavailable
during that period. This was the only major delay in the
demonstration schedule. Start-up was originally scheduled
for June 30, 1973. Some design modifications based on
ongoing experience at the Mystic Station of Boston Edison
caused slight construction delays. Dryer delivery was
delayed about one month beyond scheduled delivery. Structural
steel reinforcement in the boiler room required more time
than construction schedules had allotted.
3.4 COST DATA
In 1969 PEPCO estimated that the capital cost of a
scrubber system was 12 to $20/KW. In the January 1974 EPA
report on the October 1973 scrubber hearings the capital
cost was given as 50 to $65/KW. PEPCO1s current in-house
estimate in 1974 dollars is in excess of $100/KW. This
installation has cost *>EPCO about $6.5 million ($68/KW) .
3-9
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Operating costs are incomplete because MgO make-up
costs and maintenance cost estimates have not been reported
by PEPCO. Their experience indicates that two additional
operators per shift will be required. Maintenance require-
ments for the present system average 50-60 man-hours/week.
Operation and maintenance costs were estimated to be $500,000
in 1974. This figure does not include fixed charges on the
total capital costs to account for interest, depreciation,
insurance and taxes. The figure also does not include FGD
system fuel costs, project management, engineering, air,
electricity, or water costs. Freight charges and operation
charges by the Rumford acid plant cost PEPCO an additional
$440,000. If the FGD plant had operated at capacity in
1974, freight costs alone would have been approximately $1.7
million.
The power consumption for the existing FGD system is
about 3.5 MW. The estimated increase in power cost for the
Dickerson Station if it were to be fully equipped with FGD
facilities, operating at an 85 percent capacity factor,
would be about 5 mills per kilowatt hour. Over 3 mills of
that amount would be the fixed charge on investment. These
costs assume an on-site MgO regeneration system. The assump-
tion is also made that the sale of elemental sulfur or
sulfuric acid will cover all fixed and operating costs
associated with an on-site sulfur or acid plant.
3-10
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4.0 FGD SYSTEM PERFORMANCE
4.1 START-UP PROBLEMS AND SOLUTIONS9
The FGD system was placed in operation on September 13,
1973. Operation since that time can be divided into the
following phases:
Phase I September 13, 1973 to January 14, 1974 -
Initial operation and debugging.
Phase II January 14 to April 15, 1974 - Maintenance
and modification.
Phase III April 15 to July 1, 1974 - Modification
verification.
Phase IV July 1 to January 28, 1975 - Performance
testing, optimization and reliability.
Phase V January 28, 1975 to August 11, 1975 -
Maintenance and modification
Phase VI August 11, 1975 to about early
September 1975 - Modification verifica-
tion
Phase I
Initial start-up and operation was reasonably smooth.
There were two shutdowns caused by failures of stainless
steel expansion bellows which allowed first stage slurry to
leak into the second stage. Examination verified that the
bellows were not made of the specified 316 stainless.
a
Adapted from "Mag-Ox Scrubbing Experience at the Coal-Fired
Dickerson Station - Potomac Electric Power Company," by
Donald A. Erdman, Project Engineer, PEPCO.
4-1
-------
The major problem was with the MgO feed system. Continual
plugging occurred in the MgO mix tank and suction lines to
the MgO make-up pumps. The problem was remedied by the
installation of a premix tank ahead of the mix tank to
ensure that scale-forming reactions would occur before the
fresh slurry entered the piping system. Steam sparging
lines were also added to heat the MgO slurry to about 160°F.
This preheat was found to be necessary to ensure MgO disso-
lution and slurry homogeneity.
The longest continuous run during this phase was 271
hours. Approximately midway through this run the boiler was
forced out for 24 hours with a tube leak. All liquid flows
and levels were maintained and flue gas was returned to the
scrubber as soon as the boiler returned to service. Phase I
concluded when the boiler shut down January 14 for annual
maintenance.
Phase II
Inspection of the scrubber system was made after about
700 hours operation. The system was basically in good
condition with absolutely no sign of scaling or buildup.
However, in the first stage where the operating pH is less
than two, there was corrosion of nuts, bolts, hanger rods,
spray nozzles, bellows and the vessel itself. Examination
determined that many corroded parts were not constructed of
specified material. There was some very minor corrosion on
316 stainless. The corrosion of the vessel occurred only in
4-2
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a few places where the protective flake glass lining had
cracked. The problem here was partly due to improper appli-
cation and partly due to construction damage after the
lining was installed.
Phase III
Operation resumed with start-up on April 15, 1974. The
intent was to operate to verify the modifications and then
to shut down to prepare the unit for performance testing.
The premix tank improved slaking but not to an acceptable
standard for long-term operation. It was decided that at
the end of April the system could be operated for performance
testing. However, further checks revealed that the inventory
of MgO was insufficient for such a test and that the remaining
storage space for sulfite was also insufficient. At that
time 130 tons of sulfite were at Rumford waiting to be
calcined. Boston Edison was using the calciner and it
appeared there was no chance of PEPCO's material being
calcined before July. Additional virgin MgO had not been
ordered as PEPCO had been expecting to be able to conduct
the test using recycled MgO. A short operation in May
emptied the MgO silo.
Chemico decided to replace the premix tank with a
"solids liquid mixing eductor" to improve slaking.
Phase IV
PEPCO received permission to use the calciner at Rumford,
Rhode Island July 1, 1974. Virgin MgO, ordered to supple-
4-3
-------
ment the expected recycled MgO, arrived near the end of
July. The first start-up was August 1. The mixing eductor
proved totally unsatisfactory, plugging continually. After
10 hours the FGD system was shut down, and the premix tank
was modified and reinstalled. Preliminary tests operating
on virgin MgO indicated an SO- removal in the 70 percent
range. When the pressure drop across the absorber throat
was increased to the design specification, a removal efficiency
in excess of 90 percent was demonstrated, using virgin MgO.
Recycled MgO was first received and introduced into the
system on August 16. The dryer feed material became sticky
and caused caking in the dryer. This was believed to be
caused by unreacted MgO in the centrifuge cake. During the
next run steam sparging was used to raise the temperature in
the MgO mix tank to correct this problem. It was also
necessary to change the dryer operating temperature on
recycled MgO. Slaking with the modified premix tank was
satisfactory on both virgin and recycled MgO.
In conjunction with Chemico, Basic, Essex and EPA, from
July to December 1974, PEPCO conducted a 6-month program to
test the FGD system, optimize operating conditions, improve
reliability and gain operating experience. There have been
no problems to rule out the technical feasibility of this
process for S02 removal. There are still some problems in
the sulfite handling equipment which is somewhat undersized
for actual operating conditions. The centrifuge hopper and
4-4
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the dryer tend to hold up material and then release it in a
slug that overloads the sulfite conveyors.
Several minor problems continue to cause shutdowns.
Examples include corrosion leaks in damaged rubber-lined
pipes, erosion leaks in second stage piping, pump seal
problems, and bearing failure in sulfite bucket elevator.
Present plans call for repairing the FGD system during
a current outage for a turbine overhaul. The system is to
be subjected to an approximate three-month test-and-demon-
stration program, beginning around July 1975.
Phase V
Pipe linings and some materials of construction were
changed. Corroded equipment was repaired. Other modifica-
tions included changing the hopper feed to the centrifuge.
Phase VI
Length of this phase of operation is limited by the
existing supply of MgO, about 3-4 weeks. The purpose of
this phase is to verify the modifications and repairs that
were made. At the conclusion of this phase a complete site
inspection will be performed by PEPCO.
4.2 PERFORMANCE TEST RUN
A performance test program has been completed by York
Research and while formal results are not available, the
indicated S02 removal efficiency is in the 88 to 96 percent
range as gas flow varies from 150,000 to 300,000 acfm.
Overall particulate removal efficiency exceeds 99 percent
whether or not the existing ESP is used.
4-5
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4.3 PERFORMANCE PARAMETERS
The FGD system at the Dickerson Power Station operated
intermittently throughout 1974. Availability figures appear
in Table 4.1. The boiler capacity factor was 81 percent in
1974. PEPCO has defined availability as the length of time
the FGD system was operating or ready for operation divided
by the total number of hours in the period. This definition
differs slightly from the more usual definition of availability,
i.e., FGD operating hours divided by boiler operating hours.
4.4 PROCESS MODIFICATIONS AND ECONOMICS FOR FUTURE
INSTALLATION
This installation is not entirely suitable for the
determination of economic parameters, mainly because it is
tied to the operation of an outdated, undersized acid manu-
facturing plant located approximately 400 miles away.
Future installation will probably be predicated on on-site
calcination and across-the-fence transfer of materials to
and from a modern, economically sized acid plant. All the
Dickerson units together, including Unit 4, an 800 MW gener-
ator to be in service by 1982, would supply enough MgSO., to
operate a 1000 ton/day sulfuric acid plant; this is about
the minimum economical size for a modern plant. It is
estimated that at best the revenue from the sale of sulfuric
acid would pay operation and maintenance costs associated
with the acid plant.
4-6
-------
Future installation will probably be predicated on on-site
calcination and across-the-fence transfer of materials to
and from a modern, economically sized acid plant. All the
Dickerson units together, including Unit 4, an 800 MW gener-
ator to be in service by 1982, would supply enough MgSO3 to
operate a 1000 ton/day sulfuric acid plant; this is about
the minimum economical size for a modern plant. It is
estimated that at best the revenue from the sale of sulfuric
acid would pay operation and maintenance costs associated
with the acid plant.
Corrosion and erosion problems have been encountered in
the existing scrubber, especially in the first stage where
pH is low. Corrosion and erosion of mild steel piping and
pumps for the second stage absorber indicate that these
items should have been rubber-lined.
The plant does not have a spare centrifuge or dryer,
which makes the FGD system quite vulnerable. A full-scale
system would likely employ more redundant critical equipment
items in several areas. All pumps are spared in this installa-
tion.
Demister deposits have not occurred. The principal
problems with the demisters have been in the form of physical
abuse from being walked on by maintenance personnel during
scrubber inspections. Although it has not been necessary to
replace the demisters it is probable that a sturdier design
will be specified for replacement units or for additional
installations.
4-7
-------
Corrosion and erosion problems have been encountered in
the existing scrubber, especially in the first stage where
pH is low. Corrosion and erosion of mild steel piping and
pumps for the second stage absorber indicate that these
items should have been rubber-lined.
The plant does not have a spare centrifuge or dryer,
which makes the FGD system quite vulnerable. A full-scale
system would likely employ more redundant critical equipment
items in several areas. All pumps are spared in this installa-
tion.
Demister deposits have not occurred. The principal
problems with the demisters have been in the form of physical
abuse from being walked on by maintenance personnel during
scrubber inspections. Although it has not been necessary to
replace the demisters it is probable that a sturdier design
will be specified for replacement units or for additional
installations.
The wet scrubber I.D. fan has not caused any problems.
The wheel is constructed of Inconel 625, and the housing is
rubber-lined.
The centrifuge tends to freeze when it is shut down
unless it is carefully and thoroughly cleaned.
Bypass dampers tend to bind and do not seal completely,
but operation has not been seriously affected and major
design modifications have not been suggested.
It was mentioned earlier that the original MgO slurry
mixing system was ineffective and that a premix tank had to
4-8
-------
be installed. The mix tank temperature must be closely
controlled in order to obtain proper dissolution of the
recycled MgO.
The bucket elevator to the MgSO, silo cannot handle the
surges that normally occur when the dryer is running at
capacity. Either a surge bin between the dryer and the
elevator or a larger elevator should be installed. The
present system will only accommodate a flow equivalent to 70
percent of dryer design capacity.
4-9
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APPENDIX A
PLANT SURVEY FORM
A-l
-------
Revision date 6/10/74
PLANT SURVEY FORM
REGEHERABLE FC-D PROCESSES
A. COMPANY AMD PLANT INFORMATION
1. COMPANY NAME Potomac Electric Power Company
2. MAIN OFFICE 1900 Pennsylvania, Washington, D.C.
3. PLANT MANAGER W. C. Jensen, Jr.
4. PLANT NAME Dickerson Station
5. PLANT LOCATION Dickerson, Maryland
6. PERSON TO CONTACT FOR FURTHER INFORMATION Don Erdman
7. POSITION Project Engineer
8. TELEPHONE NUMBER (202) 872-2441
9. DATE INFORMATION GATHERED February 10, 1975
10. PARTICIPANTS IN MEETING AFFILIATION
T. Devitt, L. Yerino PEDCo
G. Isaacs PEDCo
J. Busik/ F. Biros EPA Washington, D.C.
EPA Research Triangle Park,
W. Ponder, R. Atherton North, Carolina
D. Erdman PEPCO
J. Harvey PEPCO
"G. Koehler Chemico
A-2 5/17/74
-------
B. PLANT DATA. (APPLIES TO ALL BOILERS AT THE PLANT).
CAPACITY, MW (Gross)
SERVICE (BASE, PEAK)
FGD SYSTEM USED
BOILER NO.
1
190
B
2
190
B
3
190**
B
95 MW
4***
800
B
C. BOILER DATA. COMPLETE SECTIONS (C) THROUGH (R) FOR EACH
1.
2.
3.
4 .
5.
6.
7 .
8.
9 .
10.
11.
*
BOILER
MAXIMUM
MAXIMUM
MAXIMUM
BOILER
BOILER HAVING AN FGD SYSTEM.
IDENTIFICATION NO. 3
CONTINUOUS HEAT INPUT 1456.4 MM BTU/IIR
CONTINUOUS GENERATING CAPACITY 190 MW
CONTINUOUS FLUE GAS RATE. 590.000 ACFM @ 259 °F
MANUFACTURER C-E
YEAR BOILER PLACED IN SERVICE 1962
BOILER
SERVICE (BASE LOAD. PEAK. ETC.) Base
STACK HEIGHT 400'
BOILER
BOILER
RATIO O
DEFINED
OPERATION HOURS/YEAR (1974) 7992.7
CAPACITY FACTOR * 81
F FLY ASH/BOTTOM ASH 9 (Est.)
AS: Kv/H GENERATED IN YEAR
MAX. CONT. GENERATED CAPACITY LN KW x 8760 HR/YR
** 182 MW (NET) when scrubber is not operating.
178.5 MW (NET) when scrubber is operating.
***
To be in service by 1983.
A-3
5/17/74
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D. FUEL DATA
1. COAL ANALYSIS (as received)
GHV (BTU/LB.)
S %
ASH %
MAX .
2.2
MIN .
1.7
AVG.
11,737
2.2
14.06
2. FUEL OIL ANALYSIS (exclude start-up fuel)
GRADE
S % N/A
ASH %
E. ATMOSPHERIC EMISSIONS
1. APPLICABLE EMISSION REGULATIONS
a) CURRENT REQUIREMENTS
AQCR PRIORITY CLASSIFICATION
REGULATION & SECTION NO.
MAX. ALLOWABLE EMISSIONS
LBS/MM BTU
b) FUTURE REQUIREMENTS,
COMPLIANCE DATE
REGULATION & SECTION NO.
MAXIMUM ALLOWABLE EMISSIONS
LBS/MM BTU
3.
PARTICULATES
so2
2.25% S (
Currently under review
Currently under review
PLANT PROGRAM FOR PARTICULATES COMPLIANCE
Particulate and SO2 compliance tied together.
Mitre Corp. Recommended Study underway -
Report due in April.
PLANT PROGRAM FOR SO2 COMPLIANCE Awaiting Mitre Report.
Retrofit est. to take 44 months from contract to start-up,
A-4
5/17/74
-------
]•'. PARTICULATK REMOVAL
1. TYPE
MANUFACTURER
EFFICIENCY: DESIGN/ACTUAL 99/99.3
MAX. EMISSION RATE* LIB/MR
LB/i-LMBTU
DESIGN BASIS, SULFUR CONTENT
MECII .
Chemico
99/99.3
0.02
E.S.P.
R-C
97.5/94
est .
FGD
G. DESUJ.FURIZATION SYSTEM DATA
1. PROCESS NAME
2. LICENSOR/DESIGNER NAME:
ADDRESS:
PL'RSON TO CONTACT:
TELEPHONE NO.:
Chemico-Basic
Chemico
1 Penn Plaza - NYC
J. Laaakos
(212) 239-5345
3. ARCHITECTURAL/ENGINEERS, NAME: Chemico
/ADDRESS:
PERSON TO CONTACT:
TELEPHONE NO.:
N/A
PROJECT CONSTRUCTION SCHEDULE:
a) DATE OF PREPARATION OF BIDS SPECS.
b) DATE OF REQUEST FOR BIDS __ !/.7_l
c) DATE OF CONTRACT AWARD __ ZZ7_!
d) DATE ON SITE CONSTRUCTION BEGAN _ IZZ2
e) DATE ON SITE CONSTRUCTION COMPLETED _ 8/7 3_
f) DATE OF INITIAL STARTUP 9/73
cj) DATE OF COMPLETION OF SHAKEDOWN
*At Max. Continuous Capacity
A-5
7/74
5/17/7-1.
-------
LIST MAJOR DELAYS IN CONSTRUCTION SCHKDULL 7\MD C'\USCS:
Minor delays only. Original start-up scheduled for
June 30, 1973. Some design mod, based on ongoing
experience - Boston. Dryer delay approximately 1
month; Brown & Root underestimated time to install
steel in building. Rumford facility unavailable
until July 1974.
6. NUMBER OF S02 SCRUBBER TRAINS USED 1
7. DESIGN THROUGHPUT PER TRAIN, ACFM @259 °F 295.000
8. DRAWINGS: 1) PROCESS FLOW DIAGRAM AND MATERIAL BALANCE
2) EQUIPMENT LAYOUT
H. SO2 SCRUBBING AGENT
1. TYPE MqQ
2. SOURCES OF SUPPLY Sea Water or Calcined
magnesite
3. CHEMICAL COMPOSITION (for each source) 90% Purity
4. EXCESS SCRUBBING AGENT USED ABOVE 3.5% XS in C'fuqe Cake*
STOICHIOMETRIC REQUIREMENTS
100 gpm 1st stage
5. MAKE-UP WATER POINT OF ADDITION 12 gpm 2nd stage
6. MAKE-UP ALKALI POINT OF ADDITION 2nd Stage
* In addition to 2-3% unavoidable MgO loss.
A-6 5/17/74
-------
J . SCRUBBER TRAIN SPECIFICATIONS
1. SCRUBBER NO. 1
T Y P E ( VENTUR I ) 2-Staqe
LIQUID/GAS RATIO, G/MCF @ 117 °r 20 (First) 40 (Second)^
GAS VELOCITY THROUGH SCRUBBER, FT/SLC
MATERIAL OF CONSTRUCTION-Shell Carbon Steel
TYPL OF LINING FRP - Dudick
INTERNALS:
TYPE (FLOATING BED, MARBLE BED, ETC . ) Venturi
NUMBER OF STAGES
TYPE AND SIZE OF PACKING MATERIAL
PACKING THICKNESS PER STAGE(b)
MATERIAL OP CONSTRUCTION, PACKING:
SUPPORTS:
SCRUBBER NO. 2 (a^
TYPE (TOWER/VENTURI)
LIQUID/GAS RATIO. G/MCF @ °F
GAS VELOCITY THROUGH SCRUBBER, FT/SEC
MATERIAL OF CONSTRUCTION'
TYPE OF LINING
INTERNALS:
TYPE (FLOATING BED, MARBLE BED, ETC.)
NUMBER OF STAGES
TYPE AND SIZE OF PACKING MATERIAL
a) Scrubber Ho. 1 is the scrubber that the flue crises first
enter. Scrubber 2 (if applicable) [follows Scrubber No. 1.
b) For floating bed, packing thickness at rest.
A-7 5/17/7/1
-------
PACKING THICKNESS PUR STAGED
MATERIAL OF CONSTRUCTION, PACKING: .
SUPPORTS:
CLEAR WATER TRAY (AT TOP OF SCRUBBER)
TYPE
L/G RATIO
SOURCE OF WATER
DEMISTER - Identical each stage
TYPE (CHEVRON, ETC.)
NUMBER OF PASSES (STAGES)
SPACE BETWEEN VANES
ANGLE OF VANES
TOTAL DEPTH OF DEMISTER
DIAMETER OF DEMISTER
DISTANCE BETWEEN TOP OF PACKING
AND BOTTOM OF DEMISTER
POSITION (HORIZONTAL, VERTICAL)
MATERIAL OF CONSTRUCTION
METHOD OF CLEANING
SOURCE OF WATER AND PRESSURE
Baffle
3 Stage Impingement
2 inch
45
12 inch
annular - 10 ft/sec
Centrate Up-Spray
FLOW RATE DURING CLEANINGS, GPM
FREQUENCY AND DURATION OF CLEANING Once/Day:
REMARKS Demister wash velocity 10 ft/sec. Washed once
per shift 2 gal/ft2 12 sections at 5 to 10 min. each,
5. REHEATF.R N/A
TYPE (DIRECT, INDIRECT)
b) For floating bed, packing thickness at rest.
A-8
5/L7/74
-------
DUTY, MMBTU/HR
HEAT TRANSFER SURFACE AREA SQ.FT
TEMPERATURE OF GAS: IN OUT
HEATING MEDIUM SOURCE
TEMPERATURE & PRESSURE
FLOW RATE
RCIIEATER TUBES, TYPE AND
MATERIAL OF CONSTRUCTION
_LB/hR
REHEATER LOCATION WITH RESPECT TO DEMISTER
METHOD OF CLEANING
FREQUENCY AND DURATION OF CLEANING
FLOW RATE OF CLEANING MEDIUM
REMARKS
LB/HR
6. SCRUBBER TRAIN PRESSURE DROP DATA
PART1CULATE SCRUBBER
S02 SCRUBBER
CLEAR VJATER TRAY
DEMISTER
REIiEATER
DUCTWORK
TOTAL FGD SYSTEM
INCHES OF WATER
6-12
10
35
A-9
5/17/74
-------
7. FRLSH WATER HAKE UP FLOV7 RATES AND POINTS OF ADDITION
TO: DEMISTER
QUENCH CHAMBER
ALKALI SLURRY liJG
PUMP SEALS
OTHER
TOTAL
FRESH WATER ADDED PER MOLE OF SULFUR REMOVED
8. BYPASS SYSTEM
CAN FLUE GAS BE BYPASSED AROUND FGD SYSTEMS
GAS LEAKAGE THROUGH BYPASS VALVE, ACFM
K. TANK DATA
ALKALI SLURRY MAKEUP TANK
PAKTICULATE SCRUBBER EFFLUENT
HOLD TANK (a)
S02 SCRUBBER EFFLUENT HOLD
TANK (a)
pll
% I Capacity
Solids (era] )
Hold up
tlPlCJ
5-10
L. S02 RECOVERY
NA.MF OF PROCESS
LICFNSOR/DESIGMER
SYSTEM'S CAPACITY
RAW MATERIAL REOUIRED
T/HK
A-10
5/11/74
-------
M. DISPOSAL OF CONTAMINANTS
PURGE STREAM, gpm
AMOUNT OF CONTAMINANTS IN STREAM
DESCRIBE METHOD OF CONCENTRATION
AND DISPOSAL OF CONTAMINANTS Purge requirement does not
exceed 5% and is accomplished through natural losses.
Present MgO loss is 10%.
N. COST DATA
1. TOTAL INSTALLED CAPITAL COST (95 MW) $6.5 x 1Q6 (PEPCO)
2. ANNUALIZED OPERATING COST
A-ll
-------
3.
COST BREAKDOWN
COST ELEMENTS
INCLUDED IN
ABOVE COST
ESTIMATE
ESTIMATED AMOUNT
OR "; OF TOTAL
INSTALLED CAPITAL
COST
YES
NO
CAPITAL COSTS
SO, ABSORPTION/DESORPTION
SYSTEM
SO. RECOVERY SYSTEM IN-
CLUDING H2S GENERATOR
GAS QUENCHING &
CLEANING
SITE IMPROVEMENTS
LAND, ROADS, TRACKS,
ENGINEERING COSTS
CONTRACTORS FEE
SUBSTATION ($500 K)
INTEREST ON CAPITAL
DURING CONSTRUCTION
ANNUALIZED OPERATING COST
FIXED COSTS
INTEREST ON CAPITAL
DEPRECIATION
INSURANCE & TAXES
LABOR COST
INCLUDING OVERHEAD
VARIABLE COSTS
RAW MATERIAL
UTILITIES
a
X
Work in progress is
capitalized.
15-1/2%
A-12
5/17/74
-------
4. COST FACTORS
a. ELECTRICITY
b. WATER
c. STEAM (OR FUEL FOR REHEATING)
d. SULFUR/SULFURIC ACID SELLING COST $/TON
e. RAW MATERIAL PURCHASING COST $/TON OF DRY SLUDGE
f. LABOR: SUPERVISOR HOURS/WEEK WAGE
OPERATOR 168
OPERATOR HELPER 168
MAINTENANCE 50-60
O. MAJOR PROBLEM AREAS: (CORROSION, PLUGGING, ETC.)
1. SO2 SCRUBBER, CIRCULATION TANK AND PUMPS.
a. PROBLEM/SOLUTION Corrosion and erosion of 2nd stage
piping and pumps . Two-year ..pipe, life. Six-month
impeller life. Rubber lining is suggested. All
pumps are spared. Centrifuge and dryer are not
spared.
2. DEMISTER
PROBLEM/SOLUTION Broken by physical abuse.
(People walking on demister) .
3. REHEATER
PROBLEM/SOLUTION.
A-13 5/17/74
-------
4. VENTURI SCRUBBER, CIRCULATION TANKS AND PUMPS
PROBLEM/SOLUTION Rut>ber^lined_fan_ with Inconel_wheel
is satisfactory.
5 . I.D. BOOSTER FAN AND DUCT WORK
PROBLEM/SOLUTION
6.
PROBLEM/SOLUTION Occasional plow breakage in centrifuge.
Occasional freeze-up d uring centri fjuge_ .5 hut down indicates
that a more thorough cleanout procedure _is_ necessary.
7- GAS QUENCHING AND CLEANING
PROBLEM/SOLUTION
5/17/74
A-14
-------
8. MISCELLANEOUS AREA INCLUDING BYPASS AND
PURGE STREAM SYSTEM
PROBLEM/SOLUTION Bypass dampers bind and leak. Piping
leaks force shutdowns. MgO mixing problem forced
installation of premix tank. Heat to 160°F. Boiling
gels slurry. Bucket elevator to MgSOi silo limits
drying to 70% design capacity. Larger buckets to be
installed.
P. DESCRIBE FACTORS WHICH MAY NOT MAKE THIS A REPRESENTATIVE
INS TALLATION No economical regen. facility. No surge
provisions.
Q. DESCRIBE METHODS OF SCRUBBER CONTROL UNDER FLUCTUATING
LOAD. IDENTIFY PROBLEMS WITH THIS METHOD AND SOLUTIONS.
IDENTIFY METHOD OF pH CONTROL AND LOCATION OF pll PROBES.
pH Control. Measure pH in second stage system. Downward
pH triggers MgO addition. Liquid flows are constant.
A-15 5/17/74
-------
S. ADDITIONAL NOTES
Actual inlet gas at 259°F. Recycle liquor at 125-130°F.
Pennwalt acid cement in stack.
90% S02 efficiency at 270,000 acfm.
4:1 turndown capability
Breaker should be installed at MgSO^ storage silo discharge,
Dryer fuel design 2 gpm. 87.3 Ib/min dry MgSO,.
Virgin MgO $150/ton FOB Florida
Compliance decision due June 1975. Also considering low
sulfur fuel.
Purchased 100 coal cars @ $80 K - 1 year delivery
A-16
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1 REPORT NO.
EPA-650/2-75-057-g
2.
3. RECIPIENT'S ACCESSION NO.
4 TITLE AND SUBTITLE
Survey of Flue Gas Desulfurization Systems
Dickerson Station, Potomac Electric Power Company
5. REPORT DATE
September 1975
6. PERFORMING ORGANIZATION CODE
7 AUTHOR(S)
8 PERFORMING ORGANIZATION REPORT NO.
Gerald A. Isaacs
9 PERFORMING OR8ANIZATION NAME AND ADDRESS
PEDCo-Environmental Specialists, Inc.
Suite 13, Atkinson Square
Cincinnati, Ohio 45246
10. PROGRAM ELEMENT NO.
1AB013; ROAP 21ACX-130
11. CONTRACT/GRANT NO.
68-02-1321, Task 6g
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
Subtask Final: 2/75-8/75
14. SPONSORING AGENCY CODE
IS SUPPLEMENTARY NOTES
16 ABSTRACT
The report gives results of a survey of a flue gas desulfurization system, utilizing
the Chemico/Basic MgO-SO2 removal/recovery process, that has been retrofitted
to handle approximately half of the exhaust gas from the 190 MW unit 3 at Potomac
E;ectric Power Company's Dickerson Station. The system was installed at a cost of
$0. 5 million. The boiler burns 2 percent sulfur coal and is equipped with a 94 per-
cent efficient electrostatic precipitator. A single two-stage scrubber/absorber is
used. The liquor streams for the two stages are separate, both operating in a
closed-loop mode. Magnesium oxide (MgO) is regenerated off-site.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b IDENTIFIERS/OPEN ENDED TERMS
c COSATI Field/Group
Air Pollution
Flue Gases
Desulfurization
Sulfur Dioxide
Magnesium Oxides
Coal
Combustion
Electrostatic Precip-
itators
Scrubbers
Absorbers
Air Pollution Control
Stationary Sources
Chemico/Basic Process
Scrubber/Absorber
13B
2 IB
07A,07D
07B
2 ID
8 DISTRIBUTION STATEMENT
Unlimited
19 SECURITY CLASS (This Report)
Unclassified
21. I
OF PAGES
20 SECURITY CLASS (This page)
Unclassified
22 PRICE
EPA Form 2220-1 (9-73)
A-17
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