United States Office of Air Quality EPA-450/3-85-012
Environmental Protection Planning and Standards March 1985
Agency Research Triangle Park NC 27711
Air
Review of New
Source Performance
Standards for
Sulfuric Acid Plants
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EPA-450/3-85-012
Review of New Source Performance
Standards for Sulfuric Acid Plants
Emission Standards and Engineering Division
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
March 1985
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This report has been reviewed by the Emission Standards and Engineering Division of the Office of Air
Quality Planning and Standards, EPA, and approved for publication. Mention of trade names or commercial
products is not intended to constitute endorsement or recommendation for use. Copies of this report are
available through the Library Services Office (MD-35), U.S. Environmental Protection Agency, Research
Triangle Park, N.C. 27711, or from the National Technical Information Services, 5285 Port Royal Road,
Springfield, Virginia 22161.
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TABLE OF CONTENTS
LIST OF ILLUSTRATIONS v
LIST OF TABLES vi
1.0 EXECUTIVE SUMMARY 1-1
1.1 Best Demonstrated Control Technology 1-1
1.2 Current S02 NSPS Levels Achievable With Best 1-2
Demonstrated Control Technology 1-3
1.3 Current Acid Mist Levels (and Related Opacity Levels)
Achievable With Best Demonstrated Control Technology
1.4 Cost Considerations Affecting the SOe NSPS 1-3
2.0 THE SULFURIC ACID MANUFACTURING INDUSTRY 2-1
2.1 Industry Characterization 2-1
2.1.1 Geographic Distribution 2-1
2.1.2 Production 2-1
2.1.3 Industrial Trends 2-6
2.2 Contact Process for Sulfuric Acid Production 2-8
2.2.1 Elemental Sulfur Burning Plants 2-9
2.2.2 Spent Acid and Other By-Product Plants 2-9
2.3 Emissions from Contact Process Sulfuric Acid Plants 2-9
2.3.1 Sulfur Dioxide 2-11
2.3.2 Acid Mist Formation 2-14
2.3.3 Visible Emissions (Opacity) 2-18
2.3.4 Oxides of Nitrogen 2-20
2.4 References 2-21
3.0 CURRENT STANDARDS FOR SULFURIC ACID PLANTS 3-1
3.1 Background Information 3-1
3.2 Facilities Affected 3-2
3.3 Controlled Pollutants and Emission Levels 3-2
3.4 Testing and Monitoring Requirements 3-4
3.4.1 Testing Requirements 3-4
3.4.2 Monitoring Requirements 3-5
3.5 References 3-7
4.0 STATUS OF CONTROL TECHNOLOGY _ 4-1
4.1 Control Technology Applicable to the NSPS Control of S02
Emissions From Contact Process Sulfuric Acid Plants
4.1.1 Dual Absorption Process 4-1
ii i
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4.1.2 Sodium Sulfite - Bisulfite Scrubbing 4-6
4.1.3 Ammonia Scrubbing 4-7
4.1.4 Molecular Sieves 4-7
4.2 Control Technology Applicable to the MSPS for Acid Mist
Emissions From Contact Process Sulfuric Acid Plants 4-8
4.2.1 Vertical Tube Mist Eliminators 4-9
4.2.2 Vertical Panel Mist Eliminators 4-12
4.2.3 Horizontal Dual Pad Mist Eliminators 4-14
4.3 References 4-17
5.0 COMPLIANCE TEST RESULTS 5-1
5.1 Analysis of NSPS Compliance Test Results 5-1
5.2 Comparison of NSPS Compliance Test Data with
Day-To-Day Emission Control Performance 5-4
5.3 Analysis of SO? Excess Emissions Reports 5-5
5.4 References 5-7
6.0 COST ANALYSIS 6-1
6.1 Dual Absorption Process 6-1
6.1.1 Capital Costs 6-1
6.1.2 Annualized Costs 6-2
6.2 Molecular Sieve Process 6-9
6.2.1 Capital Costs 6-9
6.2.2 Annualized Costs 6-9
6.3 Sodium Sulfite-Bisulfite Process 6-9
6.3.1 Capital Costs 6-9
6.3.2 Annualized Costs 6-11
6.4 Ammonia Scrubbing 6-11
6.4.1 Capital Costs 6-11
6.4.2 Annualized Costs 6-16
6.5 Mist Eliminators 6-21
6.5.1 Capital Costs 6-21
6.5.2 Annualized Costs 6-21
6.6 Sulfur Dioxide Monitors 6-21
6.6.1 Capital Costs 6-21
6.6.2 Annualized Costs 6-23
6.7 Cost Effectiveness 6-23
6.7.1 Sulfur Dioxide Control 6-23
6.7.2 Sulfuric Acid Mist Control 6-25
6.8 References 6-28
iv
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LIST OF FIGURES
Figure No. Page
2-1 Contact Process Sulfuric Acid Plants
Completed in U.S. Since 1971 2-4
2-2 Gross Annual Production of Sulfuric Acid
(New and Fortified), 1971 to 1983 2-5
2-3 Sulfuric Acid Consumed in U.S. by End
Use, 1983 2-8
2-4 Contact-Process Sulfuric Acid Plant Burning
Elemental Sulfur 2-11
2-5 Contact-Process Sulfuric Acid Plant Burning
Spent Acid 2-13
2-6 Sulfuric Acid Plant Feedstock Conversion
vs. Volumetric and Mass S02 Emissions at
Various Inlet S02 Concentrations by Volume 2-16
2-7 Sulfuric Acid Plant Concentrations of Mist for
Mass Stack Emissions per Unit of Production at
Inlet SO? Volume Concentrations 2-20
4-1 Dual Absorption Sulfuric Acid Plant Flow
Diagram 4-5
4-2 Vertical Tube Mist Eliminator Installation 4-10
4-3 Vertical Panel Mist Elminator Installation 4-13
4-4 Horizontal Dual Pad Mist Eliminator 4-16
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LIST OF TABLES
Table No. Page
2-1 NSPS Sulfuric Acid Plants 2-2
2-2 Sulfuric Acid Production 2-6
2-3 Sulfur Dioxide Feed and Emissions for
Four-Stage Converters 2-14
4-1 Contact Sulfuric Acid Plants Built Since
Proposal of the NSPS 4-2
5-1 NSPS Compliance Test Results for Sulfuric
Acid Plants 5-2
6-1 Capital Cost Summary - Incremental Cost for
Dual Absorption 750 TPD Plant 6-3
6-2 Capital Cost Summary - Incremental Cost for
Dual Absorption 1500 TPD Plant 5-4
6-3 Consumption and Unit Cost Estimates for
Annual Incremental Operating Cost of Dual
Absorption 6-5
5-4 Annualized Cost Summary - Incremental Cost
for Dual Absorption 750 TPD Plant 6-7
6-5 Annualized Cost Summary - Incremental Cost for
Dual Absorption 1500 TPD Plant 6-8
6-6 Capital and Annualized Cost Summary -
Molecular Sieve Process 6-10
6-7 Capital Cost Summary - Sodium Sulfite-Bisulfite
Scrubbing 750 TPD Plant 6-12
6-8 Capital Cost Summary - Sodium Sulfie-Bisulfite
Scrubbing 1500 TPD Plant 6-13
6-9 Annualized Cost Summary - Sodium Sulfite-Bisulfite
Scrubbing 750 TPD Plant 5-14
6-10 Annualized Cost Summary Sodium Sulfite-Bisulfite
Scrubbing 1500 TPD Plant 5-15
VI
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Table No. Page
6-11 Capital Cost Summary - Ammonia
Scrubbing 750 TPD Plant 6-17
6-12 Capital Cost Summary - Ammonia Scrubbing
1500 TPD Plant 6-18
6-13 Annual ized Cost Summary - Ammonia Scrubbing
750 TPD Plant 6-19
6-14 Annual ized Cost Summary - Ammonia Scrubbing
1500 TPD Plant 6-20
6-15 Capital and Annual ized Cost Summary -
Mist Eliminators 6-22
6-16 Capital and Annualized Cost Summary -
Continuous Sulfur Dioxide Monitors 6-24
6-17 Cost Effectiveness - Sulfur Dioxide Control 6-26
6-13 Cost Effectiveness - Sulfuric Acid Mist Control 6-27
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1.0 EXECUTIVE SUMMARY
The objective of this report is to review the new source performance
standards (NSPS) for sulfuric acid plants in terms of developments in control
technology, economics and new issues that have evolved since the original
standard was promulgated in 1971. The achievability of the standard and the
potential for making the standard more restrictive are analyzed in the light
of technical and cost considerations and compliance test data available for
plants built since the promulgation of the NSPS. The NSPS review includes
the S02 emission and acid mist emission standards. The opacity standard,
while included in the sulfuric acid plant NSPS, is not reviewed separately
since it is directly related to the acid mist emission standard. The following
paragraphs summarize the results and conclusions of the analysis.
1.1 3est Oemonstrated Control Technology
Sulfur dioxide and acid mist are present in the tail gas from all contact
process sulfuric acid production units. In modern four-stage converter
contact process plants burning sulfur with approximately 8 percent SO? in the
converter feed and producing 98 percent acid, S02 and acid mist emissions are
generated at the rate of 26 to 56 Ib/ton of 100 percent acid and 0.4 to 4
Ib/ton of 100 percent acid, respectively. The dual absorption process is the
best demonstrated control technology* for S02 emissions from sulfuric acid
*It should be noted that standards of performance for new sources
established under Section 111 of the Clean Air Act reflect emission
limits achievable with the best adequately demonstrated technological
system of continuous emission reduction (taking into consideration
the cost of achieving such emission reduction, as well as any nonair
quality health and environmental impacts and energy requirements).
1-1
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plants, while the high efficiency acid mist eliminator is the :v?3t demonstrated
control technology for acid mist emissions. These two emission control
systems have become the systems of choice for sulfuric acid plants built or
modified since the promulgation of the NSPS. Forty of the 46 new or modified
sulfuric acid production plants built since 1971 and subject to NSPS incorporate
the dual absorption process, and all 4-6 plants use the high efficiency acid
mist eliminator.
1.2 Current S02 NSPS levels Achievable With Best Demonstrated Control
Technology
All sulfuric acid production units subject to NSPS have demonstrated
compliance with the current SO? NSPS control level of 4 Ib/ton. The compliance
test results for dual absorption plants showed a considerable range from a
low of 0.12 Ib/ton to a high of 3.8 Ib/ton. The average SOg emission level
obtained in the TISPS compliance tests for dual absorption plaits is about one
order of magnitude lower than the S02 emission level obtained from uncontrolled
single absorption plants. Information received on the performance of several
sulfuric acid plants indicates that low S02 emission results achieved in
NSPS compliance tests apparently do not reflect day-to-day S02 emission
levels. These levels appear to rise toward the standard as the conversion
catalyst ages and its activity drops. Rased on these considerations, it is
recommended that the level of S02 emissions as specified in the current NSPS
not be changed at this time.
1-2
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1.3 Current Acid Mist Levels (and Related Opacity Levels) Achievable
With Best Demonstrated Control Technology
All 46 sulfuric acid production units subject to NSPS showed compliance
with the current acid mist NSPS control level of 0.15 Ib/ton of 100 percent
acid. The NSPS compliance test data are all from plants with acid mist
emission control provided by the high efficiency acid mist eliminator. The
data show a wide range with a low of 0.004 Ib/ton to a high of 0.15 Ib/ton.
Acid mist emission (and related opacity) levels are unaffected by factors
affecting S02 emissions, e.g., conversion catalyst aging. Rather, acid
mist emissions are primarily a function of moisture levels in the sulfur
feedstock and air fed to the sulfur burner, and the efficiency of final
absorber operation. The spread observed in NSPS compliance test values is
probably a result of variation in these factors. Making the acid mist standard
more stringent is not believed to be practicable at this time because of the
need to provide a margin of safety due to in-plant operating fluctuations,
which introduce variable quantities of moisture into the sulfuric acid
production line.
1.4 Cost Considerations Affecting the S02 NSPS
The cost effectiveness of control was estimated for four types of S02
control systems: dual absorption, ammonia scrubbing, sodium sulfite scrubbing,
and molecular sieve adsorption. The cost effectiveness ranged from $245 to
$625 per ton of S02 removed for the large (1,500 TPD) model plant size and
from $282 to $751 per ton for the small (750 TPD) model plant size. For both
plant sizes, dual absorption was estimated to be the most cost effective
control option.
1-3
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The cost analysis for acid mist control showed essentially no difference
in cost effectiveness ($47-50 per ton of acid mist removed) for the vertical
tube (Brinks type) and the horizontal dual pad (York type) mist eliminators
for the two model plant sizes.
1-4
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2.0 THE SULFURIC ACID MANUFACTURING INDUSTRY
2.1 Industry Characterization
2.1.1 Georgraphic Distribution
In 1971 there were 167 contact process sulfuric acid and oleum
plants in the United States. By 1977 the number of plants had decreased
to 150 and 32 sulfuric acid units were subject to the NSPSJ In September
of 1984 there were 46 plants subject to the NSPS2 out of a total of 132
pi ants.^ Table 2-1 provides a summary of the number of units subject to
NSPS and their design tonnage.
Figure 2-1 shows the geographical distribution of contact process
sulfuric acid units subject to the NSPS. The heaviest concentration of
new units is in Region IV (Southeast). The high concentration of sulfuric
acid units constructed in Florida since 1971 can be explained by the
presence of rich phosphate rock deposits. More than BO percent of the
phosphate rock mined goes into the manufacture of phosphate fertilizers,4,5
which is also the end use of two-thirds of the total U.S. sulfuric acid
production.6 Since most sulfuric acid is consumed near its point of
manufacture, units with production dedicated for phosphate fertilizer
manufacture will usually be located near phosphate rock deposits.
2.1.2 Producti on
U.S. production of sulfuric acid from July 1983 through June 1984
totalled approximately 37.7 minion tons, representing an average yearly
increase of 2.2 percent (722,000 tons) since 1971.7>8 Figure 2-2 shows total
annual production of sulfuric acid for 1971 to 1983, including production
by the lead chamber process, which has been phased out of the industry.
2-1
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TABLE 2-1. NSPS SULFURIC ACID PLANTS
Company
Agrico Chemical Co.
Allied Corp.
American Cyanamid
Badger Army
Ammunition PI ant
Beker Ind. Inc.
CF Ind. Inc.
GIL Chem. Inc.
Conserv. Inc.
Farmland Ind.
Freeport Chem. Co.
Gardinier, Inc.
'*!. R. Grace K Co.
Location
S. Pierce, FL
Donal dsonvill e, LA
Anacortes, WA
Westwego, LA
Savannah, GA
Baraboo, WI
Conda, 10
Tan, LA
Bartow, FL
Plant City, FL
Plant City, FL
Sayerville, NJ
Nichols, FL
Bartow, FL
Uncle Sam, LA
Tampa, FL
Bartow, FL
Unit
10
11
10
11
0
1
1
1
1
2
7
G
D
C
h
1
3
4
0
7
9
4
5
6
Capacity
(TPD)
2000
2000
1800
1800
115
1600
800
350
1200
800
2000
1500
1500
1000
1000
2000
1600
1600
1250
1750
2600
1800
1800
1800
2-2
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TABLE 2-1. NSPS SULFURIC ACID PLANTS (c —O
Company
Industrial Chemicals
International
Mineral s ^
Chemical s Corp.
Mississippi Chem.
Corp.
Occidental Chem.
Corp.
PVS Chem. Inc.
Ronn S Haas Corp.
Shell Chen. Co.
J.R. Simplot Co.
Texasgul f , Inc.
USS Agri -Chemical s
Location
Penuelas, PR
New Wai es, FL
Pascagoula, MS
White Springs, FL
Copley, OH
Deer Park, TX
Wood River, IL
Helm, CA
Pocatello, ID
Aurora, NC
Ft. Meade, FL
Unit
1
1
2
3
4
5
3
C
0
E
F
1
3
1
4
1
2
3
4
5
1
2
Capacity
(TPO)
60
2750
2750
2750
2500
2500
1500
1800
1800
2000
2000
250
800
360
1800
500
600
1525
1525
3100
2200
2200
2-3
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FIGURE 2-1
CONTACT PROCESS SULFURIC ACID PLANTS COMPLETED IN U.S. SINCE 1971
PUERTO RICO -1
-------
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Production by the contact process represented 99.3 percent of ':ota1
production in 1971, increased to 99.7 percent in 1975, and 100 percent
in 1983. Table 2-2 shows the increase in sulfuric acid production by
region from 1975 through 1983. Production in the South represented
70 percent of the U.S. Total in 1975 and 77 percent in 1983.9
TABLE 2-2. SULFURIC ACID PRODUCTION
(Thousand tons of 100% H2S04)
Regi on
Northeast
North Central
West
Soath
1975
1,903.7
3,089.2
4,528.2
21 ,535.7
Change Total Production
1983 (%) 1983 (%)
1,440.1 -24 4
2,040.3 -34 6
4,736.3 +5 13
28,074.9 +30 11
The growth of the sulfuric acid industry since promulgation of the
NSPS has been largely dominated by the growth in the phosphate fertilizer
industry in the early and mid-seventies. Of the 46 contact process
sulfuric acid units subject to NSPS, the output of at least 36 units is
dedicated to the acidulation of phosphate rock as the first step in the
manufacture of wet-process phosphoric acid and superphosphate fertilizers,
About 81 percent of the contact process sulfuric acid is produced
from elemental sulfur, representing approximately 76 percent of the toal
sulfur consumption in the U.S. The remaining acid is made from iron
2-6
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pyrites (3 percent); byproduct sulfuric acid from smelters ('J. percent);
and hydrogen sulfide, spent alkylation acid, and acid slud;:- from petroleum
refineries (8 percent) JO
Sulfuric acid is produced in various concentrations and in four
grades: commercial, electrolyte or high purity, textile (having low
organic content), and chemically pure (C.P.) or reagent grade. The
various end uses of sulfuric acid are shown in Figure 2-3. In addition
to the manufacturing of fertilizer, other major uses are petroleum refining
(6 percent), inorganic chemicals (3 percent), synthetic rubber and plastics
(3 percent), and inorganic chemicals (3 percent) Jl An increasing number of
sulfuric acid consumers, specifically fertilizer manufacturers, produce
their own sulfuric acid for captive use.
2.1.3 Industrial Trends
U.S. sulfuric acid production in 1971 was 29.0 million tons,12 and
approximately 36.6 million tons in 1983J3 Production is expected to
increase to 48.0 million tons by the year 1995j^
Tables 2-1, and 2-2, and Figure 2-1 show the strong trend towards
siting sulfuric acid plants in the southern States. Over 77 percent of
the sulfuric acid design capacity is located in EPA Regions IV and VI.
In 1971, EPA projected two new units to be coming on-line each y^ar for
the next several years. On the average, three to four new units have
actually been completed each year s.i nee 1971. Of the total of 46 new
units, over half are located in Florida. Most of the sulfuric acid
2-7
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100% EQUIVALENT SULFURIC_ACiD CONSUMPTION (xlp3), metric tons
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production units in the South are captive in nature with the output going
into phosphate fertilizer production at the same plant comolax. As
stated earlier, 77 percent of the 1983 total national production of
sulfuric acid was in the South. Therefore, based on the influence of
high phosphate fertilizer production on the new construction in Region IV,
and on the production trends of sulfuric acid most units projected to
be coming on-line in the foreseeable future will probably be located in
the South.
The location of sulfuric acid plants is not dependent on the location
of sources of sulfur, but rather on the location of various industries
associated with the use of sulfuric acid; i.e., the fertilizer and petroleum
refining industries.
2.2 Contact Process for Sulfuric Acid Production1^
All contact sulfuric acid manufacturing processes incorporate three
basic operations: (1) burning of sulfur or sulfur-bearing feedstocks to
form S02, (2) catalytic oxidation of S02 to $03, and (3) absorption of
$03 in a strong acid stream. The several variations in the process are
due principally to differences in feedstocks. The least complicated
systems are those that burn elemental sulfur. Where there are appreciable
organics and moisture as in spent acid and acid sludge, additional operations
are required to remove moisture and particulates prior to catalysis and
absorption. The compositiion of feedstock can affect the sulfur conversion
ratio, the volume of exhaust gases, and the character and rate of pollutant
releases.
2-9
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2.2.1 Elemental Sulfur Burning Plants
Figure 2-4 is a schematic diagram of a contact sulfuric plant burning
elemental sulfur. Sulfur is burned to form a gas mixture which is
approximately 8 to 10 percent sulfur dioxide, 1.1 to 13 percent oxygen,
and 79 percent nitrogen. Combustion air is predried by passing through
a packed tower circulating 98 percent sulfuric acid which acts as a
desiccant. Drying of the air minimizes acid mist formation and resultant
corrosion throughout the system.
S02 is oxidized to 803 in the presence of a catalyst containing
approximately 5 percent vanadium pentoxide. The temperature of the
reacting gas mixture increases as the composition approaches equilibrium.
Maximum conversion to $03 requires several conversion stages with
intermediate gas cooling. The gas exiting the converter is cooled
in an economizer to temperatures between 230° and 260°C, and $63 is
absorbed in 98 percent sulfuric acid circulating in a packed tower.
The acid content and temperature must be carefully controlled to prevent
excessive 803 release.
If fuming sulfuric acid (oleum) is produced, the 863 containing
gases are first passed through an oleum tower which is fed with acid
from the 98 percent absorption system. The gas stream from the oleum
tower is passed through the 98 percent acid absorber for recovery of
residual sulfur trioxide.
2.2.2 Spent Acid and Other By-Product Plants
Where spent acid, sludge, and similar feedstocks are employed, the
processes are more elaborate and expensive than sulfur-burning plants
2-10
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BLOWER
STEAM JO
4ATMOSPHERE
BOILER FEED WATER
STORAGE
PRODUCT
FIGURE 2-4
CONTACT-PROCESS SULFURIC ACID PLANT BURNING
ELEMENTAL SULFUR
-------
due to the fact that the sulfur dioxide containing gas stream is
contaminated. Gases must he cleaned if high-quality acid 15 to be
produced. This requires additional gas cleaning and cooling equipment
to remove dust, acid mist, and gaseous impurities, along with excessive
amounts of water vapor. Purification equipment consists of cyclones,
electrostatic dust and mist precipitators, plus scrubbers and gas-cooling
towers in various combinations. Figure 2-5 shows one configuration of a
spent acid plant. The balance of the process following the drying tower
is essentially the same as an elemental sulfur-burning plant.
A few plants burning only hydrogen sulfide or hydrogen sulfide plus
elemental sulfur use a simplified version of the above process. Wet gases
from the combustion chamber and waste heat boiler are charged directly to
the converter with no intermediate treatment. Gases from the converter
flow to the absorber, through which 70 to 93 percent sulf'jric acid is
circulating. In such a "wet gas" plant much of the sulfur trioxide
from the converter is in the form of acid mist which is not absorbed in
the absorption tower. High efficiency mist collectors are used both to
recover product and to minimize air pollution.
2.3 Emissions from Contact Process Sulfuric Acid Plants15
2.3.1 Sulfur Dioxide
Mass S02 emissions vary inversely as a function of the sulfur
conversion efficiency (i.e., fraction of S02 oxidized to 803). For sulfur
burning plants, the inlet S02 concentration to the catalytic converters
normally ranges between 7.5 and 8.5 percent, but can be as high as 10.5
percent. Conversion efficiency depends upon the number of stages in the
catalytic converter and, to a lesser extent, on the amount of catalyst.
2-12
-------
ro
i
r—SPENT ACID
-SULFUR
- FUEL OIL
WATER
FURNACE DUST WASTE HEAT GAS GAS ,-,..,,,,„>,«„,
COLLECTOR BOILER SCRUBBER COOLER p^tcMTATORS
S02
STRIPPER
r-*. TO
[ATMOSPHERE
^ -k
DRYING
TOWER
*• ACID TRANSFER <
ABSORPTION
TOWER
93% ACID PUMP TANK COOLER
ACID COOLERS 98% ACID PUMP TANK
FIGURE 2-5
CONTACT-PROCESS SULFURIC ACID PLANT
BURNING SPENT ACID
-------
Most plants built prior to 1960 had only three catalyst stages,
and overall conversion efficiencies were approximately 95 t.D 96 percent.
Sulfur burning plants built since I960 generally have four or five
stages and efficiencies normally range between 96 and 98 percent. For
three-stage plants, S02 release ranges between 56 and 70 Ib/ton and
for four-stage plants, between 26 and 56 Ib/ton.
Spent acid plants followed the same design trend. Most three-stage
plants were built prior to 1960 and four-stage plants have usually been
built after 1960. Typical S02 concentrations in the converter feed,
conversion efficiencies, and resultant emissions for plants burning
sulfur, H2$ or primarily acid sludge are given in Table 2-3.
TABLE 2-3. SULFUR DIOXIDE FEED AMD EMISSIONS FOR
FOUR-STAGE CONVERTERS
Hydrogen Sul
(•with some •
Feedstock Sulfur sulfur comp(
SOg in converter feed, 7.5 to 8.5 7
% by volume
S02 emissions, Ib/ton 26 to 56 50 to 36
100% acid
SOg emissions, ppm 1500 to 1500 to
bv volume 4000 4000
fide
Dther Acid
Dunds) Sludge
6 to 8
30 to 112
1500 to
4000
2-14
-------
Exit S02 concentrations from contact plants vary as a function
of the SC>2 content of dry gases fed to the converter. Where S02
strength is relatively low, there is a significantly greater volume
of gases handled per ton of acid produced.
A plant with 4.0 percent SC>2 in the dry gases to the converter
will exhaust over two and one-half times the gas volume of a plant
o
operating on a 10.0 percent S02 stream, i.e., 147,500 ft /ton vs.
54,500 ft3/ton.
The relationship between mass emission rate, sulfur conversion and
S02 exit concentrations has been plotted in Figure 2-6 for plants of
various S02 strengths. The curve can be used for uncontrolled single
absorption plants and for those plants equipped with tail gas removal
systems or with the dual absorption process. It can be seen that the
NSPS of 4.0 15 per ton of acid requires 99.7 percent sulfjr conversion
(dual absorption) or an equivalent SO? exit gas concentration of 280 ppm.
This conversion is achieved by the dual absorption technique. At 98
percent conversion, which is optimum for most single absorption contact
plants, exit S02 concentrations can vary from 1,400 to 4,000 ppm as the
inlet S02 content varies from 4.0 to 10.0 percent.
2.3.2 Acid Mist Formation
The sulfuric acid liquid loading in the tail gas from the absorber
in a contact process plant is classified into two broad areas based on
the acid particle size: (1) spray, which is defined as acid particles
larger than 10 microns, and (2) mist, which is defined as acid particles
smaller than 10 microns. The EPA method for measuring sulfuric acid mist
(Method 8) reports $03 gas as well as particulate acid mist.
2-15
-------
Sulfur Conversion - Percent of Feedstock Sulfur
10,000
5000
o.
i
3
200
150
100
O O o CN
1.0
2.0 3.0 4.0 5.0
10.0 15 20 30
100
S02 Emissions - Lb Per Ton of 100% H,S04 Produced
FIGURE ^ -0
SULFURIC ACID PLANT FEEDSTOCK SULFUR CONVERSION
VS. VOLUMETRIC AND MASS SO. EMISSIONS AT VARIOUS
INLET SO2 CONCENTRATIONS BY VOLUME
2-16
-------
Spray is primarily formed by mechanical generation of pa-'-.icles that
are formed when a gas and liquid are mixed together. Examo'es of spray
formation are liquid droplets formed by nozzles and liquid entrainment
leaving a packed tower. A typical tower design in a modern acid plant
will have a spray loading of 0.08 to 0.15 grains per actual cubic foot
(gr/ft^) under normal operating conditions.
Acid mist formation is more complex to define than spray. There are
two primary mechanisms of acid mist formation. The first mechanism is
the reaction between two vapors forming a liquid or solid. This is best
exemplified by the reaction of sulfur trioxide and water vapors to form
submicronic sulfuric acid mist.
H2°(water vapor) + S03(gas) * H2s°4(liquid particulate)
Tne second mechanism of mist formation is vapor condensation in the
bulk gas phase by lowering the gas stream temperature beyond the liquid
dew point. The dew point of a sulfuric acid under typical conditions is
about 300° to 350°F. However, because of the uncertainties of non-ideal-
conditions and wall effects, the gas stream temperature is normally
maintained between 375° and 425°F. This is done to insure that acid mist
is not present to attack metal equipment.
The formation of sulfuric acid mist in an acid plant is due to a
combination of these mechanisms. When a gas stream containing 863, ^SOq.
and H20 vapor is cooled below the liquid dew point, the H;jS04 vapor condenses
and the 503 vapor and ^0 vapor combine to form ^$04, which also condenses.
Submicronic mist particles will be formed when the gas is cooled faster
2-17
-------
than the condensable vapor can be removed by mass transfer p.?., "shock
cooling"). The conditions for "shock cooling" are present i the absorbing
towers of an acid plant.
The practical key to controlling mist formation is to keep the moisture
content in a gas stream as low as possible. As an example of mist forming
capability of extraneous water, 1 ounce of water vapor carried through
the plant has the potential to produce 2.35 gr/ft^ of submicronic acid mist.
The water content of the gas stream will be increased if any of the
following conditions are present:
1. High organic content of contaminated elemental sulfur (sulfur
burning plants only).
2. Acid mist carryover from upstream equipment.
3. Inadequate drying of the process air stream.
d. Low absorbing tower acid strengths.
\t acid strengths below 98.5 percent, the acid begins to exert a measurable
water vapor pressure. The optimum absorbing tower acid has the minimum
vapor pressure of both water (minimizing mist formation problems) and
sulfur tri oxide (minimizing 803 slippage).
In oleum producing plants, greater quantities and a much finer mist
are produced. From 85 to 95 weight percent of the particles are less
than 2 microns in diameter as compared with about 30 percent less than
2 microns for 98 percent acid production. Acid mist emissions prior to
control equipment range between 0.4 to 4 Ib/ton for sulfur burning contact
plants producing no oleum to about 1 to 10 Ib/ton for spent acid burning
plants producing oleum, based on an 8 percent SOg feed to the converter.
2-18
-------
Spent acid plants characteristically form acid mist in the early
stages of the process. This requires mist removal prior to Joying and
oxidation as well as from the tail gas after absorption.
"Wet gas" plants burning hydrogen sulfide deliberately form acid mist
by not drying the process gas. Much of this mist is recovered as product
acid with gas cooling equipment and high efficiency mist eliminators or
electrostatic precipitators.
For a given mass emission rate, acid mist concentrations vary as a
function of the exhaust gas volume and the SO? concentration of the gases
fed to the converter. Figure 2-7 shows a relationship between mass emission
rates and concentrations over a range of S02 strengths. The curves can be
used with any gas stream before or after mist eliminators, provided there
is no di1uti on.
2.3.3 V i sib1e Emissions (0paci ty )
Acid "list in exhaust gases creates visible emissions ranging from
white to blue depending on particle size, concentration and background.
-(here there is no control of mist, opacities generally range from 80 to
100 percent.
The effect of acid mist on opacity is very dependent on the size of
the mist particle. The smaller particles scatter light more, producing a
denser plume. Nevertheless, it has been demonstrated that opacity of
the plume from an efficient $03 absorber is a function of acid mist
concentration and that visible emissions can he eliminated by minimizing
acid mist levels in the acid plant tail gas or through the use of a good
mist eliminator. At the current NSPS acid mist control level, there are
essentially no visible emissions (less than 10 percent opacity).
2-19
-------
0.02 0.03 0.04 0.10 0.20 0.30 0.50
ACID MIST EMISSIONS, Ib H2S04/T OF 100 PERCENT H2 S04 PRODUCED
1.00
FIGURE 2-7
SULFURIC ACID PLANT CONCENTRATIONS OF MIST
FOR MASS STACK EMISSIONS PER UNIT OF
PRODUCTION AT INLET SO2 VOLUME CONCENTRATIONS
2-20
-------
2.3.4 Oxides of Nitrogen
Nitrogen oxides present in the converter gas also cause acid mist
emissions, since they reduce the efficiency of the absorption tower.
Nitrogen oxides may result from the fixation of atmospheric nitrogen in
high temperature sulfur furnaces, or may be formed from nitrogen compounds
in the feedstocks. Nitrogen oxides can be held to a reasonable minimum
by using the same techniques which have been applied to steam generators.
For instance, in the decomposition of spent acid containing nitrogen
compounds, operation at furnace temperatures less than about 2000°F and a
low oxygen content will generally keep nitrogen oxides concentrations
be!ow 100 ppm.
2-21
-------
2.4 REFERENCES
1. Orabkin, M. and K. J. Brooks (Mitre Corporation). A Review of
Standards of Performance for New Stationary Sources - Sulfjric Acid
Plants. Prepared for U.S. Environmental Protection Agency, Research
Triangle Park, N.C. Publication No. EPA-450/3-79-003. January 1979.
p. 4-1 .
2. Information generated from the following sources:
a. Stationary Source Compliance Division, U.S. Environmental
Protection Agency. Compliance Data System Source Data Report. Printouts
dated February 3, 1984, and January 25, 1985. 92 p.
b. Tennessee Valley Authority. World Fertilizer Capacity -
Sulfuric Acid. Printout dated August 16, 1984. 12 p.
c. SRI international. 1984 Directory of Chemical Producers.
Menlo Park, California. 1984.
d. Letter and attachments from Thomas, W.C., State of Florida
Department of Environmental Regulation, to Beck, L.L., EPA. May 21, 1984.
a. Massoglia, M.F., D.D. McFadden and L.L. Piper (Research
Triangle Institute). The NSPS Triennial Review: Final Report.
Prepared for U.S. Environmental Protection Agency, Washington, D.C. RTI
Publication No. RTI/2747/01-13F, December 20, 1984.
f. Telephone Conversations initiated by Lee Beck, U.S.
Environmental Protection Agency, to the following individuals:
Conversation Date
February
February
March 1 ,
March 29
November
November
November
December
December
December 5
December 5
January 23
January 23
January
January
January
19
19
5,
5,
February 4,
February 4,
13, 1984
16, 1984
1984
1984
19, 1984
1984
1984
1984
1984
1984
1984
1985
1984
1985
1985
1985
1985
1985
25
28
28
Person Contacted
Bruce Varner
Rick Watman
Mike Pucci
Mark Hooper
Ken Roberts
John Cole
Beverly Foster
Steve Riva
Ed Chromanski
Ann Zownier
John Hoi 1ingsworth
Jerry Vetter
Pat McCoy
Sammy Amerson
Johnnie Cole
Fred Roe
Sammy Amerson
John Ledger
Affil iation
EPA, Region V
EPA, Region III
EPA, Region II
EPA, Region X
Florida Dept. of Environmental Regulation
Florida Dept. of Environmental Regulation
EPA, Region IV
EPA, Region II
NJ Bureau of Air Pollution Control
NJ Bureau of Air Pollution Control
CIL Chemicals, Inc.
Beker Industries, Inc.
EPA, REgion V
NC Division of Environmental Management
Florida Dept. of Environmental Regulation
GA Environmental Protection Division
NC Division of Environmental Management
daho Division of Environmental Management
2-22
-------
February 5, 1985 Ed Chromanski NJ Bureau of Air Pollution Control
February 5, 1985 Byron Sullivan NJ Bureau of Air Pollution Control
February 8, 1985 Ed Chromanski NJ Bureau of Air Dilution Control
February 14, 1985 Craig Rushin EPA, ^gion VI
February 22, 1985 Chris Roeder Florida Dept. of Environmental Regulation
March 14, 1985 Lynn Malcolm Ohio Environmental Protection Agency
March 27, 1985 Charles Meskal Fresno County Air Pollution Control District
3. Bureau of the Census. Current Industrial Reports - Sulfuric
Acid. U.S. Department of Commerce, Washington, D.C. Publication No.
MA28B(83)-1. July 1984. 6 p.
4. Office of Air Quality Planning and Standards. Phosphate Rock
Plants - Background Information for Proposed Standards. U.S. Environmental
Protection Agency, Research Triangle Park, N.C. Publication No.
EPA-450/3-79-017. September 1 979. p. 3-1.
5. Bureau of Mines. Minerals Yearbook, 1983, Volume 1. Metals and
Minerals. U.S. Department of the Interior, Washington, D.C. 1984, p. 671.
6. Ibid, p. 838.
7. Bureau of Census. Current Industrial Report - Sulfur Acid.
U.S. Department of Commerce, Washington, D.C. Publication No. M28A(77)-14
Supplenent 1. June 1978.
8. Reference 3.
9. References 1, 3, and 7.
10. Reference 5, p. 840.
1 1 . Reference 5, p. 838.
12. Reference 7.
13. Reference 3.
14. Predicasts, Inc. PTS Time Series Dialog Information Retrieval
Service. File No. 799008. Predicasts, Inc., Cleveland OH. Printout
accessed February 1985. 2 p.
15. Reference 1, pp. 4-11 through 4-15.
16. Reference 1, pp. 4-15 through 4-23.
2-23
-------
3.0 CURRENT STANDARDS FOR SULFURIC ACID PLANTS
3.1 Background Information
Prior to the promulgation of the NSPS in 1971, almost all existing
contact process sulfuric acid plants were of the single-absorption design
and had no SOg emission controls. Emissions from these plants ranged
from 1500 to 6000 ppm S02 by volume, or from 21.5 lb of S02/ton of
100 percent acid produced to 85 lb of S02/ton of 100 percent acid produced.
Several State and local agencies limited S02 emissions to 500 ppm from new
sulfuric acid plants, but few such facilities had been put into operation.^
Many sulfuric acid plants utilized some type of acid mist control
prior to 1971, but several had no controls whatsoever. Uncontrolled acid
mist emissions varied between 2 and 50 mg/scf, which is equivalent to about
0.4 to 9 lb of H2S04/ton of 100 percent acid produced, the lower figure
representing emissions from a plant burning high-purity sulfur. State and
local regulatory agencies had only begun to limit acid mist emissions to
more stringent levels. For example, some agencies had adopted limits of 1 and 2
mg/scf, respectively, for new and existing plants.
It is estimated that S02 emissions from sulfuric acid plants totalled
530,000 tons in 1971 and 180,000 tons in 1983.2 This represents a 66 percent
drop in S02 emissions from this industry during a time period when production
increased by 26 percent. It is not known what portion of this drop in SOg
emissions is due to NSPS-controlled plants or to existing plants covered by
State Implementation Plans (SIP).
No corresponding data are available for the effect of the NSPS on acid
mist emissions from the industry.
3-1
-------
3.2 Facilities Affected
The NSPS regulates sulfuric acid plants that were planned or under
construction or modification as of August 17, 1971. Each sulfuric acid
production unit (or "train") is the affected facility. The standards of
performance apply to contact-process sulfuric acid and oleum facilities
that burn elemental sulfur, alkylation acid, hydrogen sulfide, metallic
sulfides, organic sulfides, mercaptans, or acid sludge. The NSPS does not
apply to metallurgical plants that use acid plants as control systems, or
to chamber process plants or acid concentrators.
An existing sulfuric acid plant is subject to the promulgated NSPS
if: (1) a physical or operational change in an existing facility causes
an increase in the emission rate to the atmosphere of any pollutant to
which the standard applies, or (2) if in the course of reconstruction of
the facility, the fixed capital cost of the new components exceeds 50 percent
of the fixed capital cost that would be required to construct a comparable
entire new facility that meets the NSPS.
3.3 Controlled Pollutants and Emission Levels
The pollutants to be controlled at sulfuric acid plants by the NSPS
are defined by 40 CFR 60, Subpart H as follows:
1. Standard for sulfur dioxide
(a) "On and after the date. . . no owner or operator subject
to the provisions of this subpart shall cause to be discharged
into the atmosphere from any affected facility any gases which
contain sulfur dioxide in excess of 2 kg per metric ton of
acid produced (A- lb per ton), the production being expressed
as 100 percent ^SO^.
3-2
-------
2. Standard for acid mist
(a) "On and after the date. . . no owner or operator subject
to the provisions of this subpart shall cause to b
-------
Emission tests from both the original dual-absorption sij1furic acid
plant and the single absorption plant with sodium sulfite-sodium bisulfite
scrubbing indicated that both operations were capable of maintaining S02
and acid mist emissions below 4 Ib/ton and 0.15 Ib/ton, respectively, at
full load operations. Additionally, control of acid mist below 0.15 Ib/ton
at these plants resulted in stack emissions below 10 percent opacity.
Continuous stack monitoring at these plants indicated that at full load,
the plants could be consistently operated so that S02 emissions woul_d be
kept within the limits of the performance standard. In Section 5.0 of this
report, NSPS emission test results for S02 and acid mist are presented for
all sulfuric acid units completed since the promulgation of the standard.
3.4 Testing and Monitoring Requirements
3.4.1 Testing Requirements^
Performance tests to verify compliance with S02, acid mist, and opacity
standards for S'jlf'jric acid plants must he conducted within 60 days after
the plant has reached its full capacity production rate, but not later than
180 days after the initial start-up of the facility. The EPA reference
methods to be used in connection with sulfuric acid plant testing include:
1. Method 8 for the concentrations of 502 and acid mist
2. Method 1 for sample and velocity traverses
3. Method 2 for velocity and volumetric flow rates
4. Method 3 for gas analysis.
3-4
-------
For Method 3, each performance test consists of three septate runs of
at least 60 minutes duration each with a minimum sample volure of 40 dry
standard cubic feet (dscf). The arithmetic mean of the three runs taken is
the test result to which compliance with the standard applies.
The sulfuric acid production rate, expressed as tons/hr of 100 percent
H2S04, is to he determined during each testing period by suitable methods
and confirmed by a material balance over the production system. Sulfur
dioxide and acid mist emissions in Ib/ton of 100 percent ^$04 are determined
by dividing the emission rate in tons/hr by the hourly 100 percent acid
production rate.
3.4.2 Monitoring Reginrernents
SOg emissions in the tail gas from sulfuric acid plants are required
to be continuously monitored. Continuous SOg monitoring instrumentation
should he able to: (1) provide a record of performance, and (2) provide
intelligence to plant operating personnel such that suitable corrections
can be made when the system is shown to be out of adjustment. Plant operators
are required to maintain the monitoring equipment in calibration and to
furnish records of $03 excess emission values to the Administrator of EPA
or to the responsible State agency.
Measurement principles used in the gas analysis instruments are:
1. Infrared absorption
2. Colorimetric titration of iodine
3. Selective permeation of S02 through a membrane
4. Flame photometric measurement
3-5
-------
5. Chromatrographic measurement
6. Ultraviolet absorption.
The ultraviolet absorption system and the iodine titration method have
received widespread application for SOj measurement in sulfuric acid plants
subject to NSPS.
The continuous monitoring system is calibrated using a gas mixture
of known S02 concentration as a calibration standard. Performance evaluation
of the monitoring system is conducted using the SOg portion of EPA Method 8.
Excess S02 emissions are required to be reported to EPA (or appropriate
State regulatory agencies) for all 3-hour periods of such emissions (or the
arithmetic average of three consecutive 1-hour periods). Periods of excess
emission are considered to occur when the integrated (or arithmetic average)
plant stack SC>2 emission exceeds the standard of 4 I'D/ton of 100 percent
produced.
3-6
-------
3.5 REFERENCES
1. Orabkin, M. and K.J. Brooks (Mitre Corporation). A Review of
Standards of Performance for New Stationary Sources - Sulfjnc Acid Plants.
Prepared for U.S. Environmental Protection Agency, Research Triangle Park,
N.C. Publication No. EPA-450/3-79-003. January 1979. p. 3-1.
2. Office of Air Quality Planning and Standards. National Air Pollutant
Emission Estimates, 1940-1983. U.S. Environmental Protection Agency,
Research Triangle Park, N.C. Publication No. EPA-450/4-84-028.
December 1984. p. 28.
3. U.S. Environmental Protection Agency. Code of Federal Regulations.
Title 40, Subpart H, SC Part 60. Washington, D.C. Office of the Federal
Register. December 23, 1971.
4. Office of Air Programs. Background Information for Proposed Standards,
U.S. Environmental Protection Agency, Research Triangle Park, N.C.
Publication No. APTD-0711. August 1971. p. 43-48.
5. Reference 3.
3-7
-------
4.0 STATUS OF CONTROL TECHNOLOGY
4.1 Control Technology Applicable to the NSPS Control of SO? Emissions
from Contact Process Sulfuric Acid Plants
There are a few physical mechanisms and many chemical means of removing
S02 from gas streams. Almost any soluble alkaline material will absorb a
significant fraction of S0£ even in a crude scrubber. For years, sulfur
dioxide has been removed from many process gases where the S0£ adversely
affected the product. The problems of removing S02 from acid plant gases
are principally that of finding the least expensive mechanism consistent
with minimal formation of undesirable by-products. The control processes
in use by the sulfuric acid industry in units installed since the
promulgation of the NSPS are reviewed below.
4.1.1 Dual Absprption Process
The dual absorption process (used partially as the basis of the rationale
for the SOg NSPS) has become the SOg control system chosen by the sulfjnc
acid industry since promulgation of the NSPS. This can be seen by examination
of Table 4-1, which presents a tabulation of the new sulfuric acid units built
since the promulgation of the NSPS together with their locations, design
capacities, basic process design, and S02 and acid mist control technologies.
As shown on Table 4-1, 40 of the 46 new units built since the promulgation
of the NSPS have employed the dual absorption process for S02 control.
This process offers the following advantages over other S02 control processes:
0 As opposed to single absorption with scrubbing, a greater fraction
of the sulfur in the feed is converted to sulfuric acid.
0 There are no by-products
4-1
-------
TABLE 4-1. CONTACT SULFUKIC ACID PLANIS BUILT SINCE PROPOSAL OF THE NSPSl
Company
Agrico Chemical Co.
All ied Corp.
American Cyanamid
Badger Army
Ammunition Plant
Beker Ind. Inc.
CF Ind. Inc.
CIL Chem. Inc.
Conserv. Inc.
Farmland Ind.
Freeport Chem. Co.
Gardinier, Inc.
W.R. Grace & Co.
Industrial Chemicals
Location
S. Pierce, FL
Donal dsonvi lie, LA
Anacortes, WA
Westwego, LA
Savannah, GA
Baraboo, WI
Conda, ID
Taft, LA
Bartow, FL
Plant City, FL
Plant City, FL
Sayerville, NJ
Nichols, FL
Bartow, FL
Uncle Sam, LA
Tampa, FL
Bartow, FL
Penuelas, PR
Unit
10
11
10
11
D
1
1
1
2
7
C
11
C
F
1
3
4
0
7
9
4
5
6
1
Year
Compl eted
1975
1975
1974
1975
1975
1978
1975
1981
1973
1974
1975
1975
1975
1975
1975
1982
1982
198?
1974
1980
1976
1976
1976
1977
1976
Capacity
(TPD)
2000
2000
1800
1800
115
1600
800
350
1200
800
2000
1500
1500
1000
1000
2000
1600
1600
1250
1750
2600
1800
1800
1800
60
Process Emission Control System
Design SO? Acid Mist
DA
DA
DA
DA
DA
DA
DA
SA
DA
SA
DA
DA
DA
DA
DA
DA
DA
DA
DA
DA
DA
DA
DA
DA
SA
Process
Process
Process
Process
Process
Process
Process
Sodium
Sulfite
Process
Ammoni a
Scrubber
Process
Process
Process
Process
Process
Process
Process
Process
Process
Process
Process
Process
Process
Process
Ammonia
Scrubber
York Demister
York Demister
York Type "S"
York Type "S"
Fiber Mi st El im.
Mist El iminator
Bri nk Demi ster
Mist Eliminator
Brink Mist El im.
Brink Demister
Brink HV Demister
Brink Demister
Brink Demister
Mist El iminator
Mi st El iminator
Monsanto CS-II
Oerni sters
Demi sters
Fiber Hist El im.
Fiber Mi st E 1 im.
Fiber Mist El im.
Brink Demister
Brink Demister
Brink Demister
Glass Fiber Mist
El iminator
-------
TABLE 4-1. CONTACT SULFURIC ACID PLANTS BUILT SINCE PROPOSAL OF THE NSPS (cont)
I
CO
Company
International
Mineral s &
Chemical s Corp.
Mississippi Chem.
Corp.
Occidental Chem.
Py* nt-4
Corp .
PVS Chem. Inc.
Rohin & Haas Corp.
Shell Chem. Co.
J.R. Simplot Co.
Texasgulf, Inc.
USS Agri -Chemicals
Location
New Wales, FL
Pascagoula, MS
White Springs, FL
Copley, OH
Deer Park, TX
Wood River, IL
Helm, CA
Pocatello, ID
Aurora, NC
Ft. Meade, FL
Unit
1
2
3
4
5
3
C
D
E
F
1
3
1
4
1
2
3
4
5
1
2
Year .
Compl eted
1975
1975
1975
1981
1981
1975
1975
1975
1980
1980
1976
1976
1978
1976
1976
1976
1976
1974
1981
1982
1982
Capacity
(TPD)
2750
275U
2750
2500
2500
1500
1800
1800
2000
2000
250
800
360
1800
500
600
1525
1525
3100
2200
2200
Process
Design
DA
DA
DA
DA
DA
DA
DA
DA
DA
DA
DA
SA
DA
DA
SA
SA
DA
DA
DA
DA
DA
Emi ssi on
SO?
*-
Process
Process
Process
Process
Process
Process
Process
Process
Process
Process
Process
Ammoni a
Scrubber
Process
Process
Ammoni a
Scrubber
Ammonia
Scrubber
Process
Process
Process
Process
Process
Control System
Acid Mist
Brink Demister
Brink Demister
Brink Demister
Brink Demister
Brink Demister
Bayer/Lurgi Mist
El iminator
Brinks Demi ster
Brinks Demister
Brinks Demister
Bri nks Derni ster
Monsanto Demi ster
Fiber Mist El im.
Fi ber Mi st El im.
Brinks Demister
Bri nks Demi ster
Brinks Demister
Bri nk ; npmi ster
Brinks Ue.-ni ster
Bri nks Demi sLi-r
Demi sters
Demi sters
SA = Single Absorption
DA = Dual Absorption
-------
0 Contact acid plant operators are familiar with the op^ations
involved.
Figure 4-1 is a process flowsheet of the dual absorption process.
The S03 formed in the first three converter stages is removed in a primary
absorption tower and the remainder of the gas is returned to the final
conversion stage(s). Removal of a product of a reversible reaction
S02 + 1/2 02 -> S03
drives the oxidation further toward completion approaching the reaction
equilibrium expressed by:
$03
K = 1/2
(S02) (02)
where K is the reaction equilibrium constant peculiar to the temperature of
the reaction and the parenthetical entities are the molar quantities of the
gases involved. The resulting 863 is absorbed in a secondary absorption
tower which yields at least 99.7 percent overall conversion of the sulfur to
sulfuric acid.2
The dual absorption process permits higher inlet S02 concentrations
than normally used in single absorption plants since the second conversion
step effectively handles the residual S02 from the first conversion step.
Higher inlet S02 concentrations permit a reduction in equipment size which
partially offsets the cost of the additional equipment required for a dual
absorption plant. The dual absorption equipment occupies little more space
than a conventional plant, even though an additional absorber is required.
Spent acid or H2S may be used as feedstock in dual absorption processes
with appropriate conventional process gas pretreatment, i.e., particulate
4-4
-------
I
CJ1
9WAC'D SS&fJB&ER C°NVERTER ECONOMI2ER *gBJgf M*ACI°
FIGURE 4-1
DUAL ABSORPTION SULFURIC ACID PLANT
FLOW DIAGRAM
-------
removal. The dual absorption process requires the same types v: equipment
as the conventional single absorber design. Although additional equipment is
required, the on-stream production factor and manpower requirement are the same.^
4.1.2 Sodium Sulfite - Bisulfite Scrubbing
Tail gas scrubbing systems are generally applicable to all classes of
contact acid plants. They can provide control of SC>2 and to some extent
303 and acid mist.
In the Well man-Power Gas process, the tail gases are first passed
through a mist eliminator to reduce acid mist. Following mist removal, the
SC>2 is absorbed in a three-stage absorber with a sodium sulfite solution.
A sodium bisulfite solution results and is fed to a heated crystallizer where
sodium sulfite crystals are formed and S02 gas and water vapor are released.
The crystals are separated from the mother liquor and dissolved in the recovered
condensat^ for recycle to the absorber. The recovered wet S02 is sent back to
the aci d pi ant.^
In all processes employing sulfite-bisulfite absorption even without
regeneration, some portion of the sulfite is oxidized to sulfate, from which
the sulfur dioxide cannot be regenerated in the heating sequence. This sulfate
must be purged from the system. In the Wei 1 man-Power Gas process, some thio-
sulfate is also formed. Apparently, the extent of oxidation is dependent on
several factors such as the oxygen content of the gas stream, the temperature
and residence time of the liquor in the recovery sections, and the presence
of contaminants that may act as oxidation catalysts.5
Since promulgation of the NSPS, two plants have used the sodium
s.il f ite-bisulfite control system. One of the plants was designed for dual
4-6
-------
absorption but later converted the second absorber to a sodiun s Pfite-
bi sufits system. The sodium sulfite-bisulfite system presented operational
difficulties, however, and was subsequently converted to an ammonia scrubber,
which is the control system the plant currently uses.^ The other plant was
designed to use sodium sulfite-bisulfite scrubbing from the outset. The
plant is part of an Army ammunition production facility, however, and has
not been used. Construction of the plant was completed in 1981 and the
plant was operated only long enough to verify its operability. Emissions
from the plant have not been measured.7
4.1-3 Ammonia Scrubblng
The ammonia scrubbing process uses anhydrous ammonia (NH3) and water
make-up in a two-stage scrubbing system to remove S02 from the acid plant
tail gas. Excess ammonium sulfite-bisulfite solution is reacted with
sulfuric acid in a stripper to evolve S02 gas and produce an ammonium
sulfate by-product solition. The S02 is returned to the acid plant and
the solution is treated for the production of fertilizer grade ammonium
sulfate. The process is dependent on a suitable market for ammonium sulfate.^
Five NSPS sulfuric acid plants use an ammonia scrubbing system
for tail gas SOg emissions control.
4.1.4 Molecu!ar Sieves
This process utilizes a proprietary molecular sieve system in which
SOg is adsorbed on synthetic zeolites. The adsorbed material is desorbed
by purified hot tail gas from the operating system and sent back to the
acid pi ant.
4-7
-------
Since the promulgation of the sulfuric acid plant NSPS, one new unit
was built with a molecular sieve system for SOg control. How,-;,^, extensive
operational difficulties with this system caused this plant to be retrofitted
with a dual absorption system for S02 control. The dual absorption system
was retrofited in January 1979 and has operated satisfactorily since that
t i me. 9
4.2 Control Technology Applicable to the NSPS^for Acid Mist Emissions
from Contact Process Sulfuric Acid Plants^
Effective control of stack gas acid mist emissions can be achieved by
fiber mist eliminators and electrostatic precipitators (ESP's). Although
ESP's are frequently used in the purification section of spent acid plants,
there is no evidence that any have been installed to treat the stack gas of
any new sulfuric acid plants. Even though ESP's have the advantage of
operating with a lower pressure drop than fiber mist eliminators (normally
less than 1 inch'of water), lack of application of this equipment to new
sulfuric acid units is probably due primarily to its relatively large size
and resultant high installation cost compared to fiber mist eliminators.
Maintenance costs (to keep the ESP's operating within proper tolerances for
the acid environment which is corrosive to the mild steel equipment) are
also high.
Mist eliminators are generally located downstream of the S02 absorbers
to collect mist generated during the production process. An exception to
this is when a sodium sulfite-bisulfite scrubber is used to control SO? emissions.
With the sodium sulfite system, it is best to locate the mist eliminator
upstream of the scrubber to minimize the formation of sulfates which must
be purged from the system. The scrubber exit gas does not normally require
mi st removal.
4-8
-------
Fiber mist eliminators utilize the mechanisms of impaction and
interception to capture large to intermediate size mist particles and of
Brownian movement to effectively collect micron to submicron size particles.
Fibers used may be chemically resistant glass or fluorocarbon. Fiber mist
eliminators are available in three different configurations covering a
range of efficiencies required for for various plants having low to high
acid mist loadings and coarse to fine mist particle sizes,
respectively. The three fiber mist eliminator configurations are:
1. Verticle tube
2. Verticle panels
3. Horizontal dual pads.
4.2.1 Vertical Tube Mist Eliminators
Tubular mist eliminators consist of a number of vertically oriented
tubular fiber elements installed in parallel in the top of the absorber
on new acid plants and usually installed in a separate tank above or beside
the absorber on existing plants. Each element consists of glass fibers
packed between two concentric screens made of 316 stainless steel. In an
absorber installation (see Figure 4-2) the bottom end cover of the element
is equipped with a liquid seal pot to prevent gas bypassing. A pool of
acid provides the seal in the separate tank design. Mist particles collected
on the surface of the fibers become a part of the liquid film which wets
the fibers. The liquid film is moved horizontally through the fiber beds
by the gas drag and is moved downward by gravity. The liquid overflows the
seal pot continuously, returning to the process.
4-9
-------
ACCESS
MANHOLE
MISTY
GAS IN
CLEAN GAS OUT
TU8E PLATE
CYLINDRICAL
^SCREENS
FIBER ELEMENTS
RECOVERED
LIQUID (MIST)
SEAL PIPES
LIQUID SEAL
LIQUID &
SOLIDS OUT
FIGURE 4-2
VERTICAL TUBE MIST ELIMINATOR INSTALLATION
4-1Q
-------
Tubular mist eliminators use inertial impaction to collect larger
particles (normally greater than 3 microns) and use direct interception and
Browm'an movement to collect smaller particles. The low superficial velocity
of gas passing through the fiber bed (20 to 40 feet per second) provides
sufficient residence time for nearly all of the small particles with random
Brownian movement to contact the wet fibers, effecting removal from the gas
stream. The probability that such a particle could pass through the bed
following the resultant greatly lengthened travel path is very low.
Design volumetric flow rate through an element is about 1000 standard
cubic feet per minute (scfm), and the number of elements required for a given
plant size can be determined from the gas volume handled at capacity.
Depending on the size of the sulfuric acid plant, anywhere from 10 to 100
elements may be used; each element is normally 2 feet in diameter and 10
feet high.
Pressure drop across the element varies from 5 to 15 inches of water
with a higher pressure drop required for a higher removal efficiency on
particles smaller than 3 microns. The manufacturer of these elements
guarantees a mist removal efficiency of 100 percent on particles larger than
3 microns and 90 to 99.8 percent on particles smaller than 3 microns with
99.3 percent being most common. These efficiencies can be achieved on the
stack gas of sulfuric acid plants burning elemental sulfur or bound-sulfur
feedstocks (spent acid, wet gas, etc.) and producing acid or oleum.
Because the vertical tube mist eliminator does not depend only upon
impaction for mist removal, it can be operated at a volumetric flow rate
considerably below design with no loss in efficiency.
4-11
-------
As can be seen on Table 4-1, the vertical tube mist eliminator
(Brinks type) is used in the great majority of new sulfuric acid units for
acid mist control.
4.2.2 Vertical Panel Mist Eliminators
Panel mist eliminators use fiber panel elements mounted in a polygon
framework closed at the bottom by a slightly conical drain pan equipped
with an acid seal pot to prevent gas bypassing. The polygon top is
surmounted by a circular ring which is usually installed in the absorption
tower and welded to the inside of the absorption tower head. Each panel
element consists of glass fibers packed between two flat parallel 315
stainless steel screens. In large high velocity towers, recent designs
have incorporated double polygons, one inside the other, to obtain more
bed area in a given tower cross section. Pressure drop across the panel is
usually about 3 inches of water.
As in the high efficiency tubular mist eliminator above, the gas flows
horizontally through the bed, but at a much higher superficial velocity
(400 to 500 ft/min) using the impaction mechanism for collection of the mist
particles. Gas leaving the bed flows upward to the exit port, while the
collected liquid drains downward across the pan and out through the seal
pot back into the tower or to a separate drain system (see Figure 4-3).
The polygon may contain 10 to 48 vertical sides, each side normally
consisting of an 18 1/2" x 53" panel. A smaller 18 1/2" x 26" panel is
available for small plants, e.g., 35 tons per day.
4-12
-------
CLEAN GASES OUT
ACCESS MANHOLE
MIST LADEN
GASES
L DISTRIBUTOR F
f™ """ mm "™"
SEAL POT
DISTRIBUTOR PAN OF TOWER
FIELD WELD
STRUCTURAL
SUPPORT
CYLINDER
ELEMENTS
IN POLYGON
FRAME
RECOVERED
LIQUID
FIGURE 4-3
VERTICAL PANEL MIST ELIMINATOR INSTALLATION
4-13
-------
Because of the large percentage of submicron mist present 'n the stack
gas of a spent acid plant and of a plant producing oleum str-^r than
20 percent, the vertical panel mist eliminator will usually give unsatisfactory
performance for these plants when used for acid mist control in the tail gas.
These units are generally used in dual absorption plants for removal of
acid mist from the intermediate absorber to protect downstream equipment
from corrosion.
Vertical panel mist eliminators normally operate with a liquid level
in the acid seal pot below the conical drain pan. Although the velocity
through the panels could be increased at lower throughputs by raising the
liquid level to cover the lower part of each panel, this would cause reentrain-
m^nt of s;>ray by the gas passing over the liquid level in the basket.
4.2.3 Horizontal Dual Pad Mist Eliminators
Two circular fluorocarbon fiber beds held by stainless steel screens
are oriented horizontally in a vertical cylindrical vessel one above the
other, so tnat the coarse fraction of the acid mist is removed by the first
pad (bottom contactor) and the fine fraction by the other (top contactor),
as shown in Figure 4-4. The bottom contactor consists of two plane segmented
sections installed at an angle to the horizontal to facilitate drainage and
give additional area for gas contact. The assembly may be located either
adjacent to or on top of the absorption tower.
This unit uses the high velocity impacting mist collection mechanism,
as does the panel mist eliminator; however, the collected acid drains down-
ward through the pads countercurrent to the gas flow producing a scrubbing
4-14
-------
action as well. Collected acid may be drained from external connections or
returned directly to the absorber through liquid seal traps.
Total pressure drop across both pads is usually about 9 inches of
water. The superficial velocity through the unit is 9 to 10 feet per second.
Hence, the diameter of the cylindrical shell and the pads is determined
from the volume of gas handled. Height requirements for the unit depend
upon whether it is located adjacent to or positioned on the absorber, but
are roughly 1.5 to 2 times the diameter of the unit.
4-15
-------
<-.
\ 'CLEAN GAS
, VJ TO ATMOSPHERE
DRAIN !
TOP CONTACTOR
r BOTTOM CONTACT!
CONTACTOR^ L DRA|N
i
MIST-LADEN <• ABSORBER
GAS IN
(COURTESY OF YORK SEPARATORS, INC.)
FIGURE 4-4
HORIZONTAL DUAL PAD MIST ELIMINATOR
4-16
-------
4.3 REFERENCES
1. Information generated from the following sources:
a. Stationary Source Compliance Division, U.S. Environmental
Protection Agency Compliance Data System Source Data Report. Printouts
dated February 3, 1984, and January 25, 1985. 92 p.
b. Tennessee Valley Authority. World Fertilizer Capacity -
Sulfunc Acid. Printout dated August 16, 1984. 12 p.
Monin P I' rS1RL1nt?rnat1i°^1* 1984 01rectory of Chemical Producers.
Menlo Park, California. 1984.
d. Letter and attachments from Thomas, W.C., State of Florida
Department of Environmental Regulation, to Beck, L.L., EPA. May 21, 1984.
e. Massoglia, M.F., D.D. McFadden and L.L. Piper (Research
Triangle Institute). The NSPS Triennial Review: Final Report.
Prepared for U.S. Environmental Protection Agency, Washington 0 f
Publication No. RTI/2747/01 -18F, December 20, 1984. ' ""
_ f. Telephone Conversations initiated by Lee Beck, U.S.
tnvironmental Protection Agency, with the following individuals:
RTI
Conversation Date
Person Contacted
Affil iation
February 1 3,
February 16,
March 29
November
December
December
December
December
January 23
January 25
January 28
January 28
February 4
February
February
February
February
1984
1984
1984
19, 1984
4,
5,
5,
8,
1984
1984
1984
1984
1985
1985
1985
1985
1985
1985
1985
1985
1985
Bruce Varner
Rick Watman
Mark Hooper
Ken Roberts
Steve Riva
Ed Chromanski
Ann Zownier
John Hoi 1ingsworth
Jerry Vetter
Sammy Amerson
Johnnie Cole
Fred Roe
Sammy Amerson
John Ledger
Ed Chromanski
Byron Sullivan
Ed Chromanski
Florida Dept.
NJ
NJ
EPA, Region V
EPA, Region III
EPA, Region X
of Environmental Regulation
EPA, Region II
Bureau of Air Pollution Control
Bureau of Air Pollution Control
CIL Chemicals, Inc.
Beker Industries, Inc.
NC Division of Environmental Management
Florida Dept. of Environmental Regulation
GA Environmental Protection Division
NC Division of Environmental Management
Idaho Division of Environmental Management
NJ Bureau of Air Pollution Control
NJ Bureau of Air Pollution Control
NJ Bureau of Air Pollution Control
4-17
-------
February 14, 1985 Craig Rushin EPA, Region VI
February 22, 1985 Chris Roeder Florida Dept. of Environmental Regulation
February 25, 1985 Pat McCoy EPA, Region V
March 14, 1985 Lynn Malcolm Ohio Environmental Protection Agency
March 27, 1985 Charles Meskal Fresno County Air Pollution Control District
2. Drabkin, M. and K. J. Brooks (Mitre Corporation). A Review of
Standards of Performance for New Stationary Sources - Sulfuric: Acid
Plants. Prepared for U.S. Environmental Protection Agency, Research
Triangle Park, N.C. Publication No. EPA-450/3-79-003. January 1979.
p. 4-1.
3. Reference 2, p. 4-26 and 4-28.
4. Reference 2, p. 4-28 and 2-29.
5. Reference 2, p. 4-29.
6. Telecon. Beck, Lee, EPA, OAQPS, with Riva, Steve, EPA,. Region II.
December 5, 1984. NSPS Sulfuric Acid Plants in EPA Region II.
7. Telecon. Beck, Lee, EPA, OAQPS, with McCoy, Pat, EPA, Region V.
February 25, 1985. NSPS Sulfuric Acid Plants in EPA Region V.
8. Reference 2, p. 4-29.
9. Reference 7.
10. Office of Air Quality Planning and Standards. Final Guideline
Document: Control of Sulfuric Acid Mist Emissions from Existing Sulfuric
Acid Production Units. U.S. Environmental Protection Agency, Research
Triangle Park, N.C. Publication No. EPA-450/2-77-019. September 1977.
pp. 6-1 through 6-23.
4-18
-------
5.0 COMPLIANCE TEST RESULTS
Several resources were accessed to determine the NSPS compliance status
of sulfuric acid plants operating in the United States, including:
EPA Regional Offices
State environmental control offices
Local environmental control offices
A printout of EPA's Compliance Data System
A study performed for EPA's Office of Planning and Policy Evaluation
by the Research Triangle Institute
The results of this survey show that there are 46 NSPS plants currently
operating in the United States, and all appear to be in compliance with the
NSPS.
5.1 Analysis of NSPS Compliance Test Results
The NSPS limits emissions of S02 to 4 pounds per ton of acid produced.
As shown in Table 5-1, results of compliance tests (Method 8) on the 46 sulfuric
acid units indicate that all have achieved the NSPS for S02. However, most
of the plants operate with S02 emissions between 2 and 4 pounds per ton, and
about half of these are in excess of 3 pounds per ton. The available information
is insufficient to determine whether the plants with highest emissions could
achieve lower emissions through changes in maintenance or operation.
Performance test results indicate that all plants have also complied
with the NSPS for acid mist, and no violation of the opacity regulation was
measured at 30 plants. Similar to the S02 emissions, many plants were found to
be operating close to the NSPS limit for acid mist and opacity. Opacity data
are not available for the remaining 16 plants.
5-1
-------
TABLE 5-1. NSPS COMPLIANCE TEST RESULTS FOR SULFURIC ACID PLANTSi
Company
Agrico Chemical Co.
Allied Corp.
American Cyan amid
Badyer Army
Ammunition Plant
Beker Ind. Inc.
Y1 CF Ind. Inc.
ro
CIL Chem. Inc.
Conserv. Inc.
Farml and Ind.
Freeport Chem. Co.
Gardinier, Inc.
W.R. Grace X Co.
Location
S. Pierce, FL
Oonal dsonvill e, LA
Anacortes, WA
Westwego, LA
Savannah, GA
Baraboo, WI
Conda, ID
Taft, LA
Bartow, FL
Plant City, FL
Plant City, FL
Sayerville, NJ
Nichols, FL
Bartow, FL
Uncle Sam, LA
Tampa, FL
Bartow, FL
Unit
10
11
10
11
D
1
1
1
1
2
7
C
I)
C
F
1
3
4
D
7
9
4
5
6
Capaci ty
(TPO)
2000
2000
1800
1800
116
1600
800
350
1200
800
2000
1500
1500
100U
1000
2000
1600
1600
1250
1750
2600
1800
1800
1800
Emi ssior
S0_£_ /
3.72
3.43
2.2
1.1
1.07
3.20
2.21
Down/Never Tested
3.7
0.84
0.12
2.76
1.81
1.12
3.7
2.2
1.2
1.3
1.96
1.37
1.98
1.8
0.9
2.5
i Test Results
Icid Mist
0.11
0.12
NA
0.08
0.004
0.02
0.09
0.12
0.01
0.02
0.05
0.05
0.04
0.12
0.12
0.07
0.08
0.11
0.05
0.06
0.06
0.13
0.09
Opacity
0
0
NA
NA
NA
NA
0
NA
NA
NA
0
2.7
0
0
0
0
5
1 '\
0
0
5.2
5.0
5.8
-------
TABLE 5-1. NSPS COMPLIANCE TEST RESULTS FOR SULRJRIC ACID PLANTS (cont)
Company
Industrial Chemicals
International
Mineral s K,
Chemicals Corp.
Mississippi Chem.
Corp.
Occidental Chem.
Corp.
en
OJ
PVS Chem. Inc.
Rohm & Haas Corp.
Shell Chem. Co.
J.R. Simplot Co.
Texasgulf, Inc.
USS Agri -Chemicals
Location
Penuelas, PR
New Wales, FL
Pascagoula, MS
White Springs, FL
Copley, OH
Deer Park, TX
Wood River, IL
Helm, CA
Pocatello, ID
Aurora, NC
Ft. Meade, FL
Unit
1
]
2
3
4
5
3
C
1)
E
F
]
3
1
4
I
2
3
4
5
1
2
Capac i ty
(TPD)
60
2750
2750
2750
2500
2500
1500
1800
1800
2000
2000
250
800
360
1800
500
600
1525
1525
3100
2200
2200
SO?
0.15
2.64
2.29
3.17
2.10
3.79
0.95
3.47
3.71
2.61
3.32
2.53
2.32
3.24
2.30
3.6
3.6
1.7
1.8
2.52
2.0
1.2
Emission Test Results
Acid Mist
0.02
0.04
0.03
0.06
0.02
0.05
0.13
0.10
0.04
0.05
0.04
0.09
0.08
0.01
0.04
0.15
0.15
0.05
0.07
0.13
0.05
0.04
Opaci ty
NA
0
0
NA
0
0
NA
0
0
0
0
NA
9.2
NA
NA
NA
NA
o
u
(J
6.6
6.6
-------
5.2 Comparison of NSPS Compliance Test Data with Oay-to-Day
Emission Control Performance^
Literature indicates that dual absorption plants can be expected to
operate after an initial startup period with fresh catalyst with $03 emissions
in the range of 2 to 3 Ib/ton. To determine whether emission control performance
deteriorates with time, a number of inquiries were made of sulfuric acid
plants that were subject to NSPS.
Data obtained from an 1,800 ton/day dual absorption sulfuric acid plant
(two production units) indicated an apparent deterioration of emission
performance following initial startup. The NSPS compliance test for this
plant (Method 8) showed emissions to average 0.93 Ib SOg per ton of acid
produced. About a year later, emission's recorded by the continuous emissions
monitor (CEM) had increased to 2.59 Ib/ton. Nineteen months after the performance
test, the emission recorded by the CEM had increased to 2.95 Ib/ton, and the
CEM data recorded 30 months after the performance test indicated a S0£ emission
rate of 3.2 Ib/ton.
Another plant had an NSPS test result of 0.95 Ib S0£/ton after fresh
catalyst was added to the absorption towers, but reported a day-to-day
operating level of 1 to 2 1 b S02/ton.
From these data, it can be seen that the S02 emission values obtained
during the initial compliance test do not necessarily reflect day-to-day
plant operating levels. These levels appear to realistically lie in the 2 to
3 Ib/ton range for dual absorption units. There is a definite trend towards
increased S02 emission values as the conversion catalyst ages and its activity
5-4
-------
correspondingly decreases. Thus, even though a large percentage of the
compliance test results are significantly less than the NSPS of 4 Ib/ton, it
appears that SO? emissions tend to rise towards the control limit as the
plant and catalyst age.
Acid mist emission (and related opacity) levels are unaffected by
conversion catalyst aging. These emissions are primarily a function of
moisture levels in the sulfur feedstock and air fed to the sulfur burner,
and the efficiency of final absorber operation.
5.3 Analysis of SOg Excess Emissions Reports
Periods of excess emissions were compiled for each NSPS sulfuric acid
plant operating in the United States during the period of April 1983 through
March 1984. 3 During that 12-month period, 13 plants reported exceedances,
with the number of individual exceedances at the 13 plants ranging in number
from 1 to 49.
Analysis of these reports indicates considerable variation among
respondents in the interpretation of the excess emission report (EER)
requirements. The general provisions of the regulations define the content
of EERs as it pertains to exceedances as:
The magnitude of excess emissions computed in accordance with
§60.13(h), any conversion factor(s) used, and the date and time
of commencement and completion of each time period of excess
emissions. [§60.7(c) (1)]
Subpart H defines exceedances as:
Periods of excess emissions shall be all three-hour periods
(or the arithmetic average of three consecutive one-hour
periods) during which the integrated average sulfur dioxide
emissions exceed the applicable standards in §60.82. [§60.84(e)]
5-5
-------
Of the 13 reports showing exceedances, only five of thes.3 correctly defined
exceedances as a 3-hour period during which the average emissions exceeded the
standard. The remaining eight reported all periods of time during which the
standard was exceeded. These periods ranged from 2 minutes to 20 hours. Many
of the shorter periods of reported exceedances (2 hours or less) probably
would not show up as exceedances if integrated over the 3-hour period in which
they occurred. Conversely, exceedances lasting over 3 hours are reported as
one exceedance, when as many as seven could be involved if converted to 3-hour
integrated periods.
The effect of the apparent oversight of the 3-hour duration reporting
requirements can be further illustrated by considering the 12 months of EER
data reported by one plant. The plant reported 39 incidences of excess
emissions for the year with the following durations:
Less than 1 hour 18
0 1 to 2 hours 5
2 to 4 hours 6
4 to 6 hours 7
0 Over 6 hours 3
Only about half of the reported exceedances would be considered excess
emissions for which reporting would be required.
5-6
-------
5.4 REFERENCES
1. Information generated from the following sources:
a. Stationary Source Compliance Division, U.S. Environmental
Protection Agency. Compliance Data System Source Data Report. Printouts
dated February 3, 1984, and January 25, 1985. 92 p.
b. Tennessee Valley Authority. World Fertilizer Capacity -
Sulfuric Acid. Printout dated August 16, 1984. 12 p.
c. SRI international. 1984 Directory of Chemical Producers.
Menlo Park, California. 1984.
d. Letter and attachments from Thomas, W.C., State of Florida
Department of Environmental Regulation, to Beck, L.L., EPA. May 21, 1984.
e. Massoglia, M.F., D.D. McFadden and L.L. Piper (Research
Triangle Institute). The NSPS Triennial Review: Final Report.
Prepared for U.S. Environmental Protection Agency, Washington, D.C.
Publication No. RTI/2747/01-18F, December 20, 1984.
f. Telephone Conversations initiated by Lee Beck, U.S.
Environmental Protection Agency, with the following individuals:
RTI
Conversation Date
Person Contacted
Affil iation
February 13,
February 1 6,
March 29
November
December 5,
December 5,
December 5,
December 5,
January 23,
January 25,
January 28,
January 28,
February 4,
February 4,
February 5,
February 5,
February 8,
February 1 4,
February 22,
February 25,
March 14,
March 27,
1984
1 984
1984
9, 1984
1 984
1984
1984
1984
1985
1935
1 985
1985
1985
1 985
1985
1 985
1985
1985
1985
1985
1985
1985
Bruce Varner
Rick Watman
Mark Hooper
Ken Roberts
Steve Riva
Ed Chromanski
Ann Zownier
John Hoi 1ingsworth
Jerry Vetter
Sammy Amerson
Johnnie Cole
Fred Roe
Sammy Amerson
John Ledger
Ed Chromanski
Byron Sull ivan
Ed Chromanski
Craig Rushin
Chris Roeder
Pat McCoy
Lynn Malcolm
Charles Meskal
Florida Dept
EPA,
EPA,
EPA,
. of
NJ
NJ
Bureau
Bureau
NC
Fl orida
Region V
Region III
Region X
Environmental Regulation
EPA, Region II
of Air Pollution Control
of Air Pollution Control
CIL Chemicals, Inc.
Beker Industries, Inc.
Division of Environmental Management
•ida Dept. of Environmental Regulation
GA Environmental Protection Division
NC Division of Environmental Management
Idaho Division of Environmental Management
NJ Bureau of Air Pollution Control
of Air Pollution Control
of Air Pollution Control
EPA, Region VI
Florida Dept. of Environmental Regulation
EPA, Region V
Ohio Environmental Protection Agency
Fresno County Air Pollution Control District
NJ
NJ
Bureau
Bureau
5-7
-------
2. Drabkin, M. and K. J. Brooks (Mitre Corporation). A Review of
Standards of Performance for New Stationary Sources - Sulfuric Acid
Plants. Prepared for U.S. Environmental Protection Agency, Research
Triangle Park, N.C. Publication No. EPA-450/3-79-003. January 1979.
pp. 5-9 through 5-11.
3. Massoglia, M.F., D.D. McFadden and L.L. Piper (Research Triangle
Institute). The NSPS Triennial Review: Final Report. Prepared for U.S.
Environmental Protection Agency, Washington, D.C. RTI Publication No.
RTI/2747/01-18F, December 20, 1984.
5-8
-------
6. COST ANALYSIS
This chapter presents current (June 1984) costs of control systems
necessary to meet the sulfur dioxide and sulfuric acid mist emission provisions
of the current NSPS for sulfuric acid plants. Four systems are analyzed for
sulfur dioxide control: the dual absorption sulfuric acid process; the
molecular sieve; the sodium sulfite-bisulfite scrubbing process; and the
ammonia scrubbing process. For control of sulfuric acid mist, two types of
mist eliminators are analyzed: the vertical tube ("candle" or "Brink") type
and the horizontal dual pad (York "S") type. Capital and annual 1 zed costs
are estimated for the following model plant sizes, all given on a 100 percent
acid basis: 681 Mg per day (750 tons per day) and 1,361 Mg per day (1,500
tons per day).
The costs presented are based primarily on information provided by
vendors and developed from literature sources. (See Appendix A for copies of
letters sent to vendors.) Capital costs are on a turnkey basis and thus
include the purchase cost of equipment and auxiliaries, taxes, freight, and
all necessary installation costs, as well as indirect costs such as engineering
and supervision, construction and field expense, contractor fee, and contingency.
Annualized costs include direct operating costs such as operating labor,
maintenance labor, utilities, and materials, as well as indirect costs such
as capital charges', overhead, property taxes, insurance, and administration.
Net annualized cost is also presented, representing total annualized cost
less the credit for recovered sulfuric acid product. Since the capital costs
were obtained from turnkey cost correlations, they are, by definition, "order-
of-magnitude" (i.e., greater than ^30 percent in accuracy). Because many of
the annualized costs were calculated directly, the accuracy of the annualized
cost estimates is expected to approach that of a study estimate (^30 percent).
Finally, cost effectiveness is given for both sulfur dioxide control and
control of sulfuric acid mist.
6.1 DUAL ABSORPTION PROCESS
6.1.1 Capital Costs
The capital costs for dual absorption are estimated for the two model
plants and represent the incremental costs of achieving the NSPS compared to
6-1
-------
an uncontrolled, i.e. single absorption, plant. The control system is
comprised of all the equipment necessary for providing the second absorption:
an absorption tower, pumps, heat exchangers, and piping and instrumentation.
The dual absorption process has essentially become the state of the
art for producing sulfuric acid. Therefore, plant vendors are the best
source of cost information concerning the second absorption portion of the
plant. Accordingly, contact with vendors provided total turnkey costs
(References 1, 2, and 3) from which were factored out the individual direct
and indirect cost components by use of appropriate factors based on data .from
Reference 8. All costs were updated to June 1984 dollars by employment of
the Chemical Engineering (CE) Plant Cost Index. Tables 6-1 and 6-2 present
the capital costs for dual absorption for the model plants.
As an example of the factoring procedure mentioned above, consider the
681 Mg per day plant for which the incremental total direct cost for dual
absorption is $1,118,000. The cost of the absorber itself is calculated to
be 50 percent of the total direct cost ($558,000). Similarly the costs for
the auxiliary equipment are as follows: $112,000 for pumps (10 percent of
total direct cost); $168,000 for piping (15 percent); and $280,000 for heat
exchangers (25 percent).
6.1.2 Annualized Costs
The annualized costs associated with owning and operating the second
absorption system are estimated for each of the model plants. Direct operat-
ing cost includes operation, maintenance, utilities and catalyst replacement.
Utilities include an "energy penalty" or loss of steam credit for reheating
of the gas prior to reentering the converter. The cost of catalyst replace-
ment includes the disposal cost for the spent catalyst. Assumed values for
consumption and unit costs associated with these items are shown in Table 6-3.
Most indirect costs were factored from capital costs or direct operat-
ing costs using appropriate factors from References 4 and 8. Capital recovery
was calculated from the total capital cost with a 10 percent rate of return
and a 10-year equipment life (References 4 and 8).
The annualized cost development includes an estimation of the credit
for sulfuric acid recovered as a result of the second absorption. The amount
6-2
-------
Table 6-1
CAPITAL COST SUMMARY
INCREMENTAL COST FOR DUAL ABSORPTION
681 MG PER DAY (750 TPD) PLANT
(June 1984 Dollars)
Cost in
Thousands
of Dollars
Direct Cost3
Absorber
Pumps
Piping
Heat exchangers
Total Direct Costb
Indi rect Costc
Engineering and supervision (10 percent of direct) 112
Construction and field expense (8 percent of direct) 89
Contractor fee (6 percent of direct) 67
Contingency (12 percent of direct) 134
Total Indirect Cost 402
Total Capital Cost 1.520
aDirect cost for each item of equipment includes cost of auxiliary equipment,
instruments and controls, taxes, freight, foundations, handling and erection,
and any other required installation costs.
bCost developed from information from References 1, 2, 3 and 8.
cPer Reference 8.
6-3
-------
Table 6-2
CAPITAL COST SUMMARY
INCREMENTAL COST FOR DUAL ABSORPTION
1361 MG PER DAY (1500 TPD) PLANT
(June 1984 Dollars)
Cost in
Thousands
of Dollars
Direct Cost3
Absorber 791
Pumps 158
Pi pi ng 237
Heat exchangers 395
Total Direct Cost5 , 1,581
- , i
i
Indirect Costc
Engineering and supervision (10 percent of direct) 158
Construction and field expense (8 percent of direct) 126
Contractor fee (6 percent of direct) 95
Contingency (12 percent of direct) 190
Total Indirect Cost 569
Total Capital Cost 2,150
aDirect cost for each item of equipment includes cost of auxiliary equipment,
instruments and controls, taxes, freight, foundations, handling and erection,
and any other required installation costs.
bCost developed from information from References 1, 2, 3 and 8.
cPer Reference 8.
6-4
-------
Table 6-3
CONSUMPTION AND UNIT
COST ESTIMATES FOR ANNUAL. INCREMENTAL
OPERATING COST OF DUAL ABSORPTION
(Based on 350 Stream Days Per Year)
Operating Cost Item
Consumption (Production)
Unit Cost
(Credit)
Operating labor
Maintenance labor
Plant water
Electricity (pumps, fan)
Loss of stream credit
Catalyst replacement (including
disposal)
Sulfuric acid credit
525 hours per year3
525 hours per year3
3.91m3 per 1,000
47.5 Gj per 1,000
335 Gj per 1,000
0.01m3 per 1,000 Mgn
17 Mg per 1,000 'MgJ
$10.89/hourb
$11.98/hourc
$0.20/m3e
$15.28/Gj9
$7.30/Gj9
$4,240/m3i
$71.66/Mgk
Reference 4.
Deference 5.
cTen percent premium over operating labor (per Reference 4).
^Calculated on basis of water required for absorption.
Reference 6.
fReference 7.
9Cost updated from Reference 13.
"Reference 9.
^Reference 4 and Reference 9 (updated).
^Calculated from incremental efficiency of dual versus single absorption.
^Reference 10.
-------
of sulfuric acid recovered for each model plant was calculated from the
difference in sulfur conversion efficiency between single and dual absorp-
tion (98 and 99.7 percent, respectively, Reference 9). Credits for this
recovered product were then calculated using a price of $65 per ton ($71.66
per Mg) as quoted in the Chemical Marketing Reporter. This price is based on
a Gulf Coast location and has remained quite stable during the period January
to June, 1984. The annualized costs for dual absorption are shown in Tables
6-4 and 6-5.
6-6
-------
Table 6-4
ANNUALIZED COST SUMMARY
INCREMENTAL COST FOR DUAL ABSORPTION
681 MG PER DAY (750 TPD) PLANT
(June 1984 Dollars)
Cost in
Thousands
of Dollars
Direct Operating Cost
Operation
Operating labor
Supervision labor3
Maintenance
Labor
Material (100 percent of maintenance labor)b
Utilities
*
Plant waterc " i
Electricity
Loss of steam credit
Catalyst replacement
Indirect Operating Cost
Overhead*^
Plant (50 percent of operating labor, super-
vision and maintenance)
Payroll (20 percent of operating labor, supervision
and maintenance labor)
Capital recovery (10 percent rate of return,
10 years equipment, life)
Insurance, taxes, and administration (four
percent of total capital cost)
Total Annualized Cost Without Credit
Credit For Recovered Acid
Net Annualized Cost
6
1
6
6
173
583
10
7
3
247
61
1,103
(290)
813
315 percent of operating labor (Reference 4)
bReference 4
cRounded to zero
^Factors from Reference 8
-------
Table 6-5
ANNUALIZED COST SUMMARY
INCREMENTAL COST FOR DUAL ABSORPTION
1361 MG PER DAY (1500 TPD) PLANT
(June 1984 Dollars)
Cost 1n
Thousands
of Dollars
Direct Operating Cost
Operation
Operating labor
Supervision labor3
Maintenance
Labor
Material (100 percent of maintenance 1abor)b
Utilities
Plant water0
Electricity
Loss of steam credit
Catalyst replacement
Indirect Operating Cost
Overhead^
Plant (50 percent of operating labor, super-
vision and maintenance)
Payroll (20 percent of operating, supervision,
and maintenance labor)
Capital recovery (10 percent rate of return,
10 years equipment life)
Insurance, taxes, and administration (four
percent of total capital cost)
Total Annualized Cost Without Credit
Credit For Recovered Acid
Net Annual i zed Cost
6
1
6
6
346
1,165
20
7
3
350
86
1,996
(580)
1,416
a!5 percent of operating labor (Reference 4)
bReference 4
CRounded to zero
^Factors from Reference 8
6-8
-------
6.2 MOLECULAR SIEVE PROCESS
6.2.1 Capital Costs
There are no known applications of the molecular sieve process to
control S02 emissions from a single absorption sulfuric acid plant.
Reference 9 identified one such plant but indicated that the owner planned to
convert the plant to double absorption. Furthermore, the major supplier of
this technology for sulfuric acid plants no longer offers the process,
presumably because the technology has not proven successful for this
application.
Nevertheless, a modest amount of cost data for the molecular sieve
process is available (Reference 11) and has been updated and presented in
Table 6-6. The reader is cautioned that: (a) the original costs are old;
(b) the original costs may have been high due to necessary developmental
costs; and (c) the costs presented in Table 6-6 are representative of a
process that may not be adequate for continuous compliance with the sulfur
dioxide emission limitation. ~ ;
6.2.2 Annualized Costs
The annualized costs for the molecular sieve process are updated from
Reference 11 and also presented in Table 6-6. The total annualized costs on
a per ton acid basis were updated from data in the reference by the use of
the CE index and are assumed to hold for all model plant sizes.
6.3 SODIUM SULFITE-BISULFITE SCRUBBING
6.3.1 Capital Costs
Reference 9 indicated no applications for sodium sulfite-bisulfite
scrubbing for sulfur dioxide NSPS compliance from the time of NSPS promulga-
tion through 1978. Furthermore, because of the wide acceptance of dual
absorption technology, it is not likely that many single absorption plants
6-9
-------
Table 6-6
CAPITAL AND ANNUALIZED COST SUMMARY
MOLECULAR SIEVE PROCESS
(June 1984 Dollars)
CAPITAL COST
Cost in
Thousands of Dollars
1,361
Mg PD _ Mq PD
Total Capital Cost Costa 3,363 5,105
ANNUALIZED COST
Cost in
Thousands of Dollars
~6811,361
Mg PD Mg PD
Total Annual i zed Costb 1,119 2.237
alncludes all direct and indirect costs for
applying the process to a new sulfur-burning
sulfuric acid plant (Reference 11).
^Includes all direct and indirect annual costs
(operating and maintenance, utilities, overhead,
depreciation, insurance, taxes, and administra-
tion) .
6-10
-------
with sodium sulfite-bisulfite scrubbing have been or will be built. Neverthe-
less, sodium-based scrubbing appears to be a viable technology for meeting
the NSPS and thus costs for this technology have been estimated.
The capital costs for the two model plants were developed from vendor
information, scaling the cost for the model plants by use of a 0.6 exponent.
The control system in each case consists of all necessary equipment to absorb
sulfur dioxide from the weak exhaust stream and regenerate a strong sulfur
dioxide stream suitable for conversion to elemental sulfur or liquid sulfur
dioxide or for recycle to the sulfuric acid plant itself. The capital cost
excludes the cost for this conversion or recycle and therefore the annualized
cost does not include a credit for recovered acid, sulfur, or liquid sulfur
dioxide. Total turnkey costs were supplied (Reference 14), which were then
factored to show direct cost and the various items of indirect costs. Tables
6-7 and 6-8 present these capital costs for the two model plants.
6.3.2 Annualized Costs
The annualized costs associated with owning and operating the sodium
sulfite-bisulfite scrubbing systems are estimated for each model plant.
Direct costs include operating labor, maintenance, and steam. The operating
labor and maintenance requirements were taken from Reference 15 and the steam
requirement from Reference 14. Unit costs for these items were taken from
Table 6-3. The cost to treat a bleed stream of sodium salts and the cost of
making caustic soda were calculated but not included as they are negligible
compared to other operating costs.
Indirect costs were factored from capital or direct operating costs
using the appropriate factors from References 4 and 8. Capital recovery was
calculated on the basis of a 10 percent interest rate and a 10 year assumed
equipment life (References 4 and 8). The annualized costs for the model
plants are shown in Tables 6-9 and 6-10.
6.4 AMMONIA SCRUBBING.
6.4.1 Capital Costs
Only two ammonia scrubbing applications were identified in the earlier
6-11
-------
Table 6-7
CAPITAL COST SUMMARY
SODIUM SULFITE-BISULFITE SCRUBBING
681 MG PER DAY (750 TPD) PLANT
(June 1984 Dollars) *
Cost in
Thousands
of Dollars
Total Direct Cost3 3,280
Indirect Cost
Engineering and supervision (10 percent of direct)
Construction and field expense (8 percent of direct)
Contractor fee (6 percent of direct) :
Contingency (12 percent of direct)
Total Indirect Cost 1,180
Total Capital Cost 4,460
aDirect cost of equipment includes cost of auxiliary equipment, instruments
and controls, taxes, freight, foundations, handling and erection, and any
other required installation costs. Costs developed from Reference 14.
6-12
-------
Table 6-8
CAPITAL COST SUMMARY
SODIUM SULFITE-BISULFITE SCRUBBING
1361 MG PER DAY (1500 TPD) PLANT
(June 1984 Dollars)
Cost in
Thousands
of Dollars
Total Direct Cost3 4,970
Indirect Cost
Engineering and supervision (10 percent of direct)
Construction and field expense (8 percent of direct)
Contractor fee (6 percent of direct)
Contingency (12 percent of direct) <
Total Indirect Cost 1,790
Total Capital Cost 6,760
aDirect cost of equipment includes cost of auxiliary equipment, instruments
and controls, taxes, freight, foundations, handling and erection, and any
other required installation costs. Costs developed from Reference 14.
6-13
-------
Table 6-9
ANNUALIZED COST SUMMARY
SODIUM SULFITE-BISULFITE SCRUBBING
681 MG PER DAY (750 TPD) PLANT
(June 1984 Dollars)
Cost in
Thousands
of Dollars
Direct Operating Cost
Operation
Operating labor3 274
Supervision laborb 41
Maintenance (4 percent of total capital cost)c 178
Utilities !
Electricity ~ ' 125
Steam 633
Indirect Operating Cost
Overheadd
Plant (50 percent of operating labor, super- 202
vision and maintenance)
Payroll (20 percent of operating, supervision, 81
and maintenance labor)
Capital recovery (10 percent rate of return, 726
10 years equipment life)
Insurance, taxes, and administration (four 178
percent of total capital cost)
Total Annual ized Cost 2,438
aLabor requirements from Reference 15.
b!5 percent of operating labor (Reference 14).
Reference 15.
dFactors from Reference 8. Assumes that 50 percent of maintenance cost is
maintenance labor.
6-14
-------
Table 6-10
ANNUALIZED COST SUMMARY
SODIUM SULFITE-BISULFITE SCRUBBING
1361 MG PER DAY (1500 TPD) PLANT
(June 1984 Dollars)
Cost in
Thousands
of Dollars
Direct Operating Cost
Operation
Operating labor3
Supervision 1aborb
Maintenance (4 percent of total capital cost)c
- Utilities
Electricity ~
Steam
412
62
270
251
1,266
Indirect Operating Cost
Overhead^
Plant (50 percent of operating labor, super-
vision and maintenance)
Payroll (20 percent of operating, supervision,
and maintenance labor)
Capital recovery (10 percent rate of return,
10 years equipment life)
Insurance, taxes, and administration (four
percent of total capital cost)
Total Annualized Cost
305
122
1,100
270
4,058
^Labor requirements from Reference 15.
b!5 percent of operating labor (Reference 14).
Reference 15.
factors from Reference 8. Assumes that 50 percent of maintenance cost is
maintenance labor.
6-15
-------
NSPS review (Reference 9). Because of the production of ammonium sulfate as
a by-product, this scrubbing process could possibly be desirable for sulfuric
acid plants that are part of a fertilizer complex. Therefore, costs for this
technology have been estimated, although the technology would probably only
be employed in preference to dual absorption in highly-specific applications.
The capital costs for the two model plants were developed from informa-
tion supplied by a vendor of this technology and using an approach similar to
that for sodium-based scrubbing. As with the sodium sulfite-bisulfite
scrubbing system, this system includes all necessary equipment to absorb
sulfur dioxide and regenerate a strong sulfur dioxide stream for further
processing. The cost of a plant to recover elemental sulfur or produce
liquid sulfur dioxide is not included. The acid plant is assumed to be part
of a fertilizer complex and thus facilities for granulating the ammonium
sulfate by-product will be available. The direct and indirect costs were
factored from the total turnkey costs (Reference 14) by employing appropriate
factors from References 4 and 8. Tables 6-11 and 6-12 present the capital
costs.
6.4.2 Annualized'Costs
The annualized costs for ammonia scrubbing are estimated for each
model plant. The direct costs include operating labor, maintenance, elec-
tricity, and the cost of ammonia, which can be noted to be the major annual-
ized cost item. The operating labor and maintenance requirements were taken
from Reference 15 while the steam and ammonia requirements were taken from
Reference 14. The unit costs for these were from Table 6-3 and from Chemical
Marketing Reporter for the unit cost of ammonia.
Indirect operating costs were factored from the capital or direct
operating costs with factors from References 4 and 8. Capital recovery is
based on a 10 percent interest rate and an assumed useful life of 10 years
for the equipment. The annualized costs for the model plants are presented
in Tables 6-13 and 6-14.
6-16
-------
Table 6-11
CAPITAL COST SUMMARY
AMMONIA SCRUBBING
681 M6 PER DAY (750 TPD) PLANT
(June 1984 Dollars)
Cost in
Thousands
of Dollars
Total Direct Cost9 1,544
Indi rect Cost
Engineering and supervision (10 percent of direct) 154
Construction and field expense (8 percent of direct) 124
Contractor fee (6 percent of direct) 93
Contingency (TZ'percent of direct) 185
Total Indirect Cost 556
Total Capital Cost 2,100
aDirect cost of equipment includes cost of auxiliary equipment, instruments
and controls, taxes, freight, foundations, handling and erection, and any
other required installation costs. Costs developed from Reference 14.
6-17
-------
Table 6-12
CAPITAL COST SUMMARY
AMMONIA SCRUBBING
1361 MG PER DAY (1500 TPD) PLANT
(June 1984 Dollars)
Cost in
Thousands
of Dollars
Total Direct Cost9 2,344
Indirect Cost
Engineering and supervision (10 percent of direct) 235
Construction and field expense (8 percent of direct) 188
Contractor fee (6 percent of direct) 141
Contingency (12-percent of direct) 282
Total Indirect Cost 846
Total Capital Cost 3,190
aDirect cost of equipment includes cost of auxiliary equipment, instruments
and controls, taxes, freight, foundations, handling and erection,, and any
other required installation costs. Costs developed from Reference 14.
6-18
-------
Table 6-13
ANNUALIZED COST SUMMARY
AMMONIA SCRUBBING
681 MG PER DAY (750 TPD) PLANT
(June 1984 Dollars)
Cost in
Thousands
of Dollars
Direct Operating Cost
Operation
Operating labopa 274
Supervision laborb 41
Maintenance (4 percent of total capital cost)c 84
Utilities _
Electricity 78
Chemicals (ammonia) 662
Indirect Operating Cost
Overhead^
Plant (50 percent of operating labor, super- 179
vision and maintenance)
Payroll (20 percent of operating, supervision, 71
and maintenance labor)
Capital recovery (10 percent rate of return, 342
10 years equipment life)
Insurance, taxes, and administration (four 84
percent of total capital cost)
Total Annual ized Cost 1,815
aLabor requirements from Reference 15.
b!5 percent of operating labor (Reference 14).
cReference 15.
dFactors from Reference 8. Assumes that 50 percent of maintenance cost is
maintenance labor.
6-19
-------
Table 6-14
ANNUALI ZED COST SUMMARY
AMMONIA SCRUBBING
1361 MG PER DAY (1500 TPD) PLANT
(June 1984 Dollars)
Cost in
Thousands
of Dollars
128
Direct Operating Cost
Operation
Operating labor
Supervision labor3
Maintenance (4 percent of total capital cost)b
Utilities
Electricity — lbb
Chemicals (ammonia) 1,323
Indirect Operating Cost
Overhead0
Plant (50 percent of operating labor, super- 243
vision and maintenance)
Payroll (20 percent of operating, supervision, 97
and maintenance labor)
Capital recovery (10 percent rate of return, 519
10 years equipment life)
Insurance, taxes, and administration (four 128
percent of total capital cost)
Total Annual i zed Cost _ _ _ _ __ - 3'014 -
aLabor requirements from Reference 15.
bl5 percent of operating labor (Reference 14).
^Reference 15. . .
factors from Reference 8. Assumes that 50 percent of maintenance cost is
maintenance labor.
6-20
-------
6.5 MIST ELIMINATORS
6.5.1 Capital Costs
The capital costs of mist eliminators for the model plants are esti-
mated on the basis of contact with equipment vendors. Note that in accord-
ance with the model plant parameters the 681 megagrams per day (750 TPD)
plant employs a "Brinks" type mist eliminator, while the 1,381 Mg per day
(1500 TPD) plant employs a York "Type S" mist eliminator. Each mist elim-
inator has an approximate efficiency of 97 percent. No data was found
on a third type — the vertical panel mist eliminator — which was discussed
in the earlier NSPS review (Reference 9). Discussion with vendors and
mention in the literature (Reference 12) has indicated that this type of mist
eliminator would not be efficient enough for this application, presumably
because of its marginal effectiveness in removing submicron particles and
possible re-entrainment problems when operating at high gas velocities. The
mist eliminator capital costs are presented in Table 6-15.
6.5.2 Annualized Costs
Because mist eliminators have no moving parts and require little
attention, the only significant direct operating cost is for moving gas
through the unit. This electricity cost has been calculated on the basis of
gas flowrate, pressure drop, and the unit cost of electricity previously
presented in Table 6-3. The maintenance requirements for the demisters would
be negligible (Reference 1) consisting of cleanout and minor repair as
necessary during scheduled annual shutdowns. Indirect costs include capital
recovery and insurance, taxes, and administration. There is also a substantial
credit for recovered sulfuric acid. The annualized costs are also summarized
in Table 6-15.
6.6 SULFUR DIOXIDE MONITORS
6.6.1 Capital Cost
The capital cost of an in-stack continuous monitor for sulfur dioxide
' ' 6-21
-------
Table 6-15
CAPITAL AND ANNUAL IZED COST SUMMARY
MIST ELIMINATORS
(June 1984 Dollars)
CAPITAL COST
Total Capital Cost in Thousands of Dollars
681 Mg Per Day (750 TPD)1361 Mg Per Day (1500 TPD)
Vertical Tube (Brinks)3 Horizontal Dual Pad (York)b
68 112
ANNUALIZED COST
Annualized Costs in
Thousands of Dollars
681 Mg Per Day 1381 Mg Per Day
(750 TPD) (1500 TPD)
Vertical Tube Horizontal Dual
(Brinks) Pad (York)
Direct Operating Cost
Utilities
Electricity^' 48 107
Indirect Operating Cost
Capital recovery (10 percent rate of 11 18
return, 10 years equipment life)
Insurance, taxes, and administration 3 4
(four percent of total capial cost)
Total Annualized Cost Without Credit 62 129
Credit for Recovered Acid (36) (73)
Net Annual 1 zed Cost 26 56
alncludes all direct and indirect costs for the purchase and installation
of the unit in the top portion of the final absorber in a new sulfur-burning
dual absorption sulfuric acid plant. (Calculated from cost data from
Reference 1.)
^Includes all direct and indirect costs for the purchase and installation
of a mist eliminator vessel above the final absorber in a new sulfur-burning
dual absorption sulfuric acid plant. (Calculated from cost data from
Reference 18.)
cPressure drops: 681 Mg per day -- 8 in. W.C.; 1381 Mg per day — 9 in. W.C.
6-22
-------
is estimated based on data supplied by vendors (References 16 and 17). The
cost of the monitor is independent of acid plant size. Each monitor is a
single-point extractive analyzer that employs a photoelectric (UV) principle.
Continuous samples are aspirated from the stack to the analyzer and results
are transmitted by a 4-20 mi Hi ampere electronic signal to the readout in the
control room in the range of 0-500 ppm. A three-tube bundle connects the
probe and the analyzer: one tube carries sample gas; the second is for
calibration gas; and the third is for high-pressure blowback air to periodica-
lly clean the probe. The analyzer is automatically calibrated once every 24
hours. It is assumed that the distance between the probe and the analyzer is
approximately 100 feet. The capital cost for continuous sulfur dioxide
monitoring is shown in Table 6-16.
6.6.2 Annualized Cost
The only direct annualized cost item for the continunous monitor that
is not negligible is for replacement of calibration gas (Reference 16).
Indirect costs include capital recovery and insurance, taxes, and administra-
tion. The annualized cost for continuous sulfur dioxide monitoring is also
shown in Table 6-16.
6.7 COST EFFECTIVENESS
6.7.1 Sulfur Dioxide Control
Cost effectiveness for the types of sulfur dioxide control is shown in
Table 6-17. For the small model plant, cost effectiveness ranges from $311
per Mg of S02 removed to $827, and for the large model plant the cost
effectiveness ranges from $270 to $687 per Mg of S0£ removed. For both
model plants, dual absorption is the least costly at $311 per Mg for the
small plant and $270 per Mg for the large plant. Recalling the caveat from
Section 6.2 concerning the costs of the molecular sieve process, it can be
seen from Table 6-17 that dual absorption is significantly more cost-effective
than other applicable control technologies. Indeed, dual absorption has
accounted for over 87 percent of the sulfuric acid plants built in the period
6-23
-------
Table 6-16
CAPITAL AND ANNUALIZED COST SUMMARY*
CONTINUOUS SULFUR DIOXIDE MONITORS
(June 1984 Dollars)
CAPITAL COST
Purchased cost of analyzer 40,800
Flexible tubing from probe to analyzer 2,950
Installation 6,000
Total Capital Cost 49,750
ANNUALIZED COST
Direct Operating Cost
Maintenance (calibration gas) '700
Indirect Operating Cost
Capital recovery (10 percent rate of return, 8,100
10 years equipment life)
Insurance, taxes, and administration (four 1,990
percent of total capital cost)
Total Annualized Cost 10.800
aCosts apply to either model plant. Costs developed from References 16 and 17
6-24
-------
1973 to 1977 (Reference 9) and undoubtedly accounts for an even greater
percentage for the period 1978 to the present. Dual absorption has become
the state of the art for producing acid, partly because it is the most
cost-effective technology for control of sulfur dioxide emissions.
6.7.2 Sulfuric Acid Mist Control
The cost-effectiveness for control of sulfuric acid mist is presented
in Table 6-18. There is essentially no difference in the cost-effectiveness
of $52 and $55 per Mg of acid removed, especially when it is considered that
the costs were developed on a slightly different basis (see footnotes for
Table 6-15). Both units are capable of performing at efficiencies higher
than the 97 percent level required for other model plants to be in compliance
(Reference 12). The horizontal dual pad mist eliminator is slightly less
cost-effective because it is defined in the model plant analysis to have a
slightly higher pressure drop (9 vs. 8 in. W.C.).
6-25
-------
Table 6-17
COST EFFECTIVENESS
SULFUR DIOXIDE CONTROL
(June 1984 Dollars)
Control Method
Annualized S0£ Removed C/E
Plant Size Cost Mg/yr $/Mg
Mg/day (TPD) ($103/yr)a (tons/yr)b ($/ton)
Dual absorption
Molecular sieve
Ammonia scrubbing
Sodium sul fite-
bisulfite scrubbing
681 (750)
1361 (1500)
681 (750)
1361 (1500)
681 (750)
1361 (1500)
681 (750)
1361 (1500)
824
1427
1130
2248
1826
3025
2449
4069
2650 (2920)
5290 (5820)
2960 (3260)
5920 (6510)
2960 (3260)
5920 (6510)
2960 (3260)
5920 (6510)
311 (282)
270 (245)
382 (347)
380 (345)
617 (560)
511 (465)
827 (751)
687 (625)
alncludes the cost of continuous sulfur dioxide monitoring.
bFor dual absorption, calculated from the incremental amount of sulfuric
acid recovered vs. single absorption; for other controls, calculated using
a removal efficiency of 95 percent and assuming a 98 percent conversion of
S02 to sulfuric acid in the single absorption process (Reference 9).
6-26
-------
Table 6-18
COST EFFECTIVENESS
SULFUR ACID MIST CONTROL
(June 1984 Dollars)
Control Method
Annualized Acid Removed C/E
Plant Size Cost Mg/yr $/Mq
Mg/day (TPD) ($lo3/yr) (tons/yrja ($/ton)
Vertical tube
(Brinks type)
681 (750)
26
504 (554)
52 (47)
Horizontal dual
pad (York type)
1381 (1500)
56
1020 (1120) 55 (50)
Calculated from acid recovery due to mist eliminator.
6-27
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6.8 REFERENCES
1. Personal communication with Mr. Douglas R. Hansen, Monsanto Enviro-
Chem, St. Louis, MO, February 17, March 5, and March 14, 1984.
(Documented by letters dated February 21, March 6, and March 20,
1984.)
2. Personal communication with Mr. Helmut'Diekmann and Mr. Chris Czoch,
Lurgi Corp., River Edge, NJ, February 24, February 28, and March 5,
1984. (Documented by letter dated March 6, 1984.)
3. Personal communication with Mr. Richard Warner, Ralph M. Parsons co.,
Pasadena, CA, March 1, 1984. (Documented by letter dated March 2, 1984.)
4. Vatavuk, William M. and Neveril, Robert B., "Part II: Factors for
Estimating Capital and Operating Costs," Chemical Engineering,
November 3, 1980.
5. U.S. Department of Commerce, Bureau of Labor Statistics, Monthly Labor
Review, May 1984.
6. "Chemical Water", Chemical Week, February 22, 1984.
7. Riedel, R.W., et al., "Alternatives in Sulfuric Acid Plant Design",
Chemical Engineering Progress, March, 1977.
8. Peters, M.S., and Timmerhaus, K.D. Plant Design and Economics for
Chemical Engineers. Third Edition McGraw-Hill, New York, NY. 1980.
9. Drabkin, Marvin, and Brooks, Kathryn J., A Review of Standards of
Performance for New Stationary Sources — Sulfuric Acid Plants,
EPA Contract No. 68-07-2526, January 1979. '
10. Chemical Marketing Reporter, Schnell Publishing Co., New York, NY,
August 13, 1984.
11. Collins, J.J., et al., "The Purasiv Process for Removing Acid Plant
Tail Gas", Chemical Engineering Progress, June 1974.
12. Final Guideline Document: Control of Sulfuric Acid Mist Emissions
from Existing Sulfuric Acid Production Units, U.S. Environmental
Protection Agency, Office of Air Quality Planning and Standards,
September 1977.
13. Friedman, Leonard J., "Sulfuric Acid Energy Design for the 80's",
Chemical Engineering Progress, February, 1982.
14. Personal communication with Mr. Al Giovanetti, Davy-McKee Corp.,
Lakeland, FL, February 23 and March 22, 1984. (Documented by letter
dated March 23, 1984.)
15. Mathews, J.C., et al., So2 Control Processes for Non-Ferrous
Smelters, EPA Contract No. 68-02-1491, January 1976.
16. Personal communication with Mr. Ronald Buck, E. I. duPont de Nemours
and Company, Inc., Wilmington, DE, August 21, 1984.
17. Personal communication with Mr. James McGeoch, Lear-Siegler, Inc.,
Havertown, PA, August 21, 1984.
18. Personal communication with Mr. Paul Fabian, York Separators, Fair-
field, NJ, March 22, 1984. (Documented by letter dated March 22,
1984.)
6-28
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TECHiNICAL REPORT DATA
(Please read Instructions on the reverse before completing;
1 REPORT NO. 2. |3. RECIPI E— S ACCESSION NO.
EPA-450/3-85-012
4. TITLE AND SUBTITLE
Review of New Source Performance Standards for
Sulfuric Acid Plants
7. AUTHOR(S)
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Office of Air Quality Planning and Standards
U.S. Environmental Protection Agency
Research Triangle Park, N.C. 27711
12. SPONSORING AGENCY NAME AND ADDRESS
DAA for Air Quality Planning and Standards
Office of Air and Radiation
U. S. Environmental Protection Agency
RTP, N.C. 27711
5. REPC "-, " DATE
Marrh 1QR5
6. PE-rORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT N
FlO. PROGRAM ELEMENT NO.
11 CONTRACT/GRANT NO.
13. TYPE OF REPORT AND PERIOD COVERE
14. SPONSORING AGENCY CODE
EPA 200/04
15. SUPPLEMENTARY NOTES ' • • '
This report reviews the current New Source Performance Standards for Sulfuric Acid
Plants. It includes a summary of the current standards, the status of current
applicable control technology, and the ability of plants to meet the current
standards.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
Air Pollution
Sulfuric Acid Plants
] Sulfur Oxides
I Standards of Performance
j Pollution Control
t. COSATI Held/Group
Air Pollution Control
13B
Release Unlimited
19. StC'JRiTC CLASS (ThisReoof',
Unclassified
5PA >=„,„, 2220-1 (Rev. a_77)
SCI~!CN 'S OBSOLETE
20 SEC'JRITV CLASS This ,-;aeeI
I ynclaos-i-£»6d
; 21 NO. OF PAGES
i 93
; P 2 PRICE
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