ENGINEERING ANALYSIS
OF
EMISSIONS CONTROL TECHNOLOGY
FOR
SULFURIC ACID MANUFACTURING PROCESSES
FINAL REPORT UNDER CONTRACT CPA 22-69-81
/
FOR
DIVISION OF PROCESS CONTROL ENGINEERING
NATIONAL AIR POLLUTION CONTROL ADMINISTRATION
PUBLIC HEALTH SERVICE
U.S. DEPARTMENT OF HEALTH, EDUCATION & WELFARE
0064C
MARCH 1970
Consulting Division
Chemical Construction Corporation
320 Park Avenue
New York, New York 10022
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CONSULTING DIVISION
CONTENTS
PAGE NO.
PART I
ABSTRACT
I - 1
PART II
PART III
INTRODUCTION
A. Objectives of the Study
B. Limitations of the Report
C. Plan of the Report
D. Acknowledgements
SULFUR 1C ACID PLANTS, OPERATING
METHODS AND GASEOUS EMISSIONS
A.
Fundamental and Operational
Considerations
Converter Design Considerations
Ideal Stage Conversion Limits
Variation of Conversion Efficiency
with Plant Capacity
Sulfuric Acid Mist
II - 1
II - 4
II - 6
II - 7
II - 9
III - 1
Acid Mist, SO and H
SO Vapor
4
B.
Classification of Sulfuric Acid Plants
Plant Classification
Plant Classification
Plant Classification
Plant Classification
Plant Classification
Plant Classification
Plant Classifications
2.4, 2. 5
Acid Production Cost
III - 12
1.0
1. 1
1. 2
1. 3
1.4
1. 5
i 2 1
2.2, 2. 3,
C.
Census of Sulfuric Acid Plants
III - 35
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CONSULTING DIVISION
PAGE NO.
PART IV
EMISSION CONTROL SYSTEMS
A. Survey of Available Systems IV - 1
B. Feasibility and Applicability Criteria IV - 7
C. Selected Processes for SO
Emission Control IV - 11
Process 1. 1. 1
Process 1. 2. 1
Process 1. 2. 2
Process 1. 2. 3
SO-SO Conversion Improvement (1.3.4)
£i O
Process 2. 1. 1
Process 2. 2. 6
Process 2. 2. 8
Process 2. 2. 14
Process 2. 2. 22
Process 2. 2. 28
Process 2. 2. 29
Process 2. 3. 3
Process 2. 4. 5
Process 2. 4. 6
D. Feasible Systems for SO and Acid Mist IV - 50
Control
System 3. 1. 1
System 3. 1. 2
System 3. 1. 3
System 3. 2. 1
System 3. 3. 1
E. Emission Control for Chamber Process IV - 57
Acid Plants
F. Comparison of Systems IV - 58
u
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CONSULTING DIVISION
PAGE NO.
PART V
ECONOMICS OF CONTROL V - 1
A. Selection of Units Costs V - 2
B. Selection of Other Operating Cost
Factors V - 3
C. Capital Investment Requirements V - 5
Variations in Capital Investment
Requirements
Variation with Acid Plant Capacity
Variation with Control System
Capability
Variation in Inlet Conditions
Variations with Control
Effectiveness
Variation for Existing and New
Plants
Multiple Units
D. Control Cost V - 11
Variation with Inlet Concentration
Variation with Control
Effectiveness
Variation with Plant Capacity
Control Cost for New and Existing
Plants
Special Situations
Economic Comparison of Control
Systems
PART VI
ECONOMIC EFFECTS OF RECOVERED SULFUR VI - 1
VALUE UTILIZATION
Partial Recycle Air Process
Total Recycle Oxygen Process
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CONSULTING DIVISION
PAGE NO.
PART VII
RECOMMENDA TIONS
A. Technology Limitations VII - 1
Applications
Control Effectiveness
Oleum Plants and Mist Control
Space Limitations
Process Development
Class 1. 1 Acid Plants
Class 1. 2 Acid Plants
Class 1. 3 and 1. 4 Acid Plants
B. Development Programs VII - 8
Resin or Molecular Sieve
Adsorbents
Oxidation Inhibitors
Plume Dispersion for Cold Stack
Gases
Development for Process 2. 3. 1
Development for Process 1. 3. 2
Chamber Acid Plant Emission
Control
PART VIII
APPENDIX
Sulfuric Acid Vapor Liquid Equilibria
SOo -Oleum Equilibria
Suiiuric Acid Production Costs
Emission Control Estimates for Control
Systems
Control Costs for Feasible Control
Systems
IV
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CONSULTING DIVISION
I
ABSTRACT
The findings of this report cover three areas -- the capabilities of various
control systems and their state of development, the cost of emission
control, and the limitations of present systems, with recommendations
for areas of further study to achieve better control effectiveness and
process reliability at lower control cost.
Existing plants can reduce their emissions somewhat by modifying their
operating conditions with little capital expenditure, but this control is
limited to about 2, 000 ppm of SO . Present technology can achieve a
£
control effectiveness of 500 ppm of SO via the dual absorption route,
u
and excellent acid mist control in the order of 0. 1 mg/SCF. No fully
developed acid plant control systems are commercially operated in the
U.S. which achieve an effectiveness of 100 ppm of SO , but there are
&
promising ones in various stages of development.
It is doubtful that there is any contact plant in the U.S. to which some
type of control system could not be applied to reduce emissions to
<500 ppm SO0, but to do so economically may be a different story.
^i
Cost of emission control varies widely with plant capacity, type of
control system and other factors. Cost of < 500 ppm SO control for
£i
a 250 T/D contact plant varies from about $. 75 to over $3 per ton of
acid. Mist control costs vary from $. 02 to $. 35/tons of acid. These
costs are predicated on an assumption that promising processes will
work as expected. Control cost is lower for large plants.
I - 1
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vl*t0mt€a6
CONSULTING DIVISION
Recommended areas for study include development of resin and molecular
sieve adsorbents, oxidation inhibitor development for tail gas recovery
processes, study of stack dispersion and factors affecting it, plus
development work on several processes, both for treatment of tail gas
and improved in-plant conversion.
I - 2
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CONSULTING DIVISION
II
INTRODUCTION
The typical design conversion efficiency of recently built sulfuric acid
plants is 98%. If this design efficiency were maintained the exit gas
concentration of SO would be 2, 000 ppm or less. Frequently, how-
£i
ever, emissions of 3, 000-4,000 ppm and more are encountered in
actual practice. Control regulations of < 500 ppm SO are being dis-
£
cussed in some areas of the country, which indicates a considerable
gap between present practice and proposed control levels.
Sulfuric acid capacity in the United States totals some 38 million short
tons per year produced in about 250 plants, of which about 215 are of
the contact type, the remainder being of the older chamber type.
Perhaps 30% of these plants have some oleum production capacity.
A census of the sulfuric acid plants in the United States appears in
Part III. Also included in this census are sulfuric acid concentrators
of the drum type. Actual production was about 28, 500, 000 ST in 1968.
Sulfuric acid is produced in a great variety of concentrations and in
four grades - commercial, electrolyte or high purity, textile, (having
low organic content,) and C.P. or reagent grade. Many of the industries
which use sulfuric acid do not actually consume the acid but change its
form. In some cases, regeneration to acid is economical, in others it
is not. Industries which are the principal users of sulfuric acid include:
the wet process phosphoric acid industry which is on the route to produce
many phosphate fertilizers, in petroleum refining, the production of
alcohols, the production of titanium dioxide for pigments, in the
II - 1
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CONSULTING DIVISION
production of ammonium sulfate, and in the production of normal super-
phosphate (the usual use of chamber acid which is more dilute than the
acid normally produced by contact plants) also, iron and steel pickling,
caprolactam, production of surface active agents, production of methyl-
methacrylate, production of hydrofluoric acid and the production of
aluminum sulfate. Industries which do not use up the sulfur values are
petroleum refining and alcohol production where the actual consumption
of the sulfur values is approximately 10% of the total quantity of acid
used, the remainder being supplied from regenerated or reconstituted
acid produced from dilute acid from the plant operation. Large amounts
of dilute sulfuric acid recovered from smelter operations are also used in
leaching operations to produce ore concentrates used in the smelters.
Most acid of all grades is consumed near the point in which it is produced;
either by the manufacturer or by nearby industries. Very little acid is
shipped more than 200 or 300 miles from the point at which it is made.
NAPCA has selected certain industrialized areas in the United States as
Air Quality Control Regions (AQCR). The geographic boundaries of each
region within an initial group of 57 are to be designated by about mid-
1970. As of March 1, 1970,28 of these have been so designated. The
AQCRs are identified by the central cities of the metropolitan areas
which they include.
Approximately 40% of the sulfuric acid plants in the United States
producing about 1
these 57 AQCRs.
producing about 1/3 of the annual H SO production are located within
^ TC
II - 2
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CONSULTING DIVISION
Problems arising from sulfuric plants are not due to the total quantity of
SC" and acid mist which they discharge to the atmosphere because these
are relatively small. Problems are generally localized and caused by
relatively high percentages of SO and/or acid mist (up to 1/2%) combined
Ct
with relatively low tail gas temperatures and often short stacks which
result in poor dispersion. The result is ground level concentrations of
SO_ and mist which may exceed desirable limits in the immediate
vicinity of a plant, especially during adverse atmospheric conditions.
Recognizing that more effective control for both existing and new plants
will be required in the near future, the Division of Process Control
Engineering (DPCE) of the National Air Pollution Control Administration
(NAPCA) financed this study by the Consulting Division of Chemical
Construction Corporation (Chemico) to evaluate the capabilities and
state of development of the available processes and devices to effect
this control, to determine the cost of control by various methods, and
to outline programs for further development of systems which appear to
have the greatest overall potential for reducing undesirable emissions
from sulfuric acid plants in the United States at the lowest cost.
The scope of the study is defined in Contract CPA 22-69-81 dated
May 23, 1969 between NAPCA and Chemico.
II - 3
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CONSULTING DIVISION
Objectives of the Study
Information developed in this study is intended to provide a basis for
management decisions by DPCE in determining the extent and direction
which their efforts should be taking in the support and management of
research and other programs for control of emissions from sulfuric
acid plants and possibly other sources.
To this end, Chemico from its extensive background in the design and
construction of all types of sulfuric acid plants has compiled back-
ground information on their characteristics and operating conditions.
A literature search was made to identify as many methods as possible
for emission control including systems normally applied to other
stationary sources which might be applicable to the conditions found
in sulfuric acid plants.
Sulfuric acid plants were classified into groups having similar problems,
to which certain types of control systems might be applied. To make
use of the classification it was necessary to compile a census of
sulfuric acid plants which are presently in operation in the United
States.
After an initial screening to remove the less effective, less applicable
and most costly systems from further consideration, the effectiveness
and cost of control of selected methods was determined for various
classifications to which they could be applied. This process identified
the characteristics of the most promising systems, and their limitations,
II - 4
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CONSULTING DIVISION
and reviewed these with respect to the foreseeable trends in emissions
regulations.
Where technology is incomplete, recommendations for development
programs have been prepared.
II - 5
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CONSULTING DIVISION
Limitations of the Report
The report is based almost in its entirety upon information available
within the Chemico organization. Some proprietary processes for
which costs and capabilities have not been disclosed have been
evaluated on available information.
It is not the intent of the report to identify the capacity or emission
level of any existing plant. The census, classification and
capacities of plants have been used to determine the approximate
number of potential applications for various processes as a measure
of relative merit.
II - 6
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CONSULTING DIVISION
Plan of the Report
The report is presented in two volumes, the first volume being the report
itself, and the second containing the literature search.
Volume one is divided into Parts I through VIII. Part I is an abstract
summarizing the report and its findings, and Part II the introduction,
presenting the purpose of the study, its limitations and the organization
of the report; Part III discusses the characteristics of operation and
emissions of the various types of sulfuric acid plants, present
emission control practice and the expected emission levels of future
paints using dual absorption or add-on control techniques. Also
included in Part III is the sulfuric acid plant census in Tables 4, 5 and
6.
Part IV lists all processes which were reviewed in preparation of the
report, a discussion of control effectiveness, the method of selection
of the processes chosen for detailed review, factors effecting reliability
of processes and the rationale for selection of the control levels which
are used to divide the several processes into categories based upon
their capabilities. Also included are descriptions of various processes
illustrated by flow diagrams.
The economics of the various processes and devices are covered in
Part V, including definitions and selection of parameters used in the
economic comparisons. Capital costs for the various processes studied
are given, and these with operating costs for the various types of H9SO
^ Tt
plants are used to derive control costs for various processes. Curves of the
II - 7
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CONSULTING DIVISION
variation of control cost with plant capacity and variation of control
cost with control effectiveness also are included, together with a
discussion of the factors influencing control cost and effectiveness.
Part VI includes a discussion of the effect of utilization of recovered
sulfur values from various other sources upon the sulfuric acid
industry. This is illustrated by flow diagrams, process descriptions,
capital and operating costs.
Part VII presents the results of the study, including the limitations of
the various processes, and outlines programs for development of
potentially promising processes or parts of processes.
Part VIII is the Appendix which includes supporting data, Including
capital cost estimates for various processes and calculations of
operating costs for the several processes as applied to different
types of H2SO plants.
II - 8
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CONSULTING DIVISION
Acknowledgements
Research Cottrell, Inc.
for cost and operating data on electrostatic precipitators
Lotepro Corp. , American Air Liquide, Inc. , and Linde
Division of Union Carbide
for cost and operating data on oxygen plants
Rohm & Haas
for use of information on resins
Norton Co.
for information on molecular sieves (ZEOLON)
II - 9
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CONSULTING DIVISION
III
SULFURIC ACID PLANTS -
OPERATING METHODS AND GASEOUS EMISSIONS
Atmospheric emissions from sulfuric acid plants vary, both in quantity
and composition, depending upon the process, the mode of operation of
the plant and the condition of the plant. All emissions which are of any
concern, however, emanate from one source - the tail-gas stack of the
plant, regardless of size, type, or acid grade produced. The qualitative
and quantitative emissions of the various classes of plants are fully
described in Part III-B.
A. FUNDAMENTAL AND OPERATIONAL CONSIDERATIONS
Emissions of objectionable sulfur compounds from sulfuric acid
plants result from either incomplete conversion of the sulfur
source to H9SO., or from carry over of acid mist and droplets
^ ~r
formed or entrained in the tail gas. The quantity of 809 present
in the tail gas is a very small fraction of the total flow, usually
less than 1%.
Converter Design Considerations
The basic contact plant reaction:
+ 1/2 0 =^
is a classic example of a reversible, exothermic, catalytic
reaction. The thermodynamics of the reaction has been thoroughly
described by Duecker and West among others.
(1) Duecker W.W. and West J.R., "The Manufacture of Sulfuric
Acid", Reinhold (1959) pp. 135-185.
Ill - 1
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CONSULTING DIVISION
The reaction is carried out in a converter in the presence of catalyst
containing V O . The SO yield is governed by chemical equilibria and
Lt U O
kinetics. Due to the adiabatic conditions and the liberation of reaction
heat (42, 342 Btu/Lb mol @ 77 F) the temperature of the reacting gas
mixture rises until the composition of the gas approaches the equilibrium
conversion, and heat must be removed if further reaction is required.
From this it is obvious that with lower feed temperatures higher
conversions may be attained, but will be accompanied by lower
reaction rates.
At lower reaction rates catalyst requirements increase thus increasing
the pressure drop through the catalyst bed, and resulting in higher
operating costs; hence there is an optimum balance between higher
conversions and lower catalyst requirements, both dependent upon
temperature. The usual commercial practice is to use feed tempera-
tures of 820-840 F in three or four stage converters with 160-180
liters of catalyst per daily ton of H0SO product, overall SO conversion
£t TC £1
being 95-98%. Below 820 F the reaction rate slows down until it is
negligible around 750 F. However, low temperature catalysts are
available which are useful at 750 F.
The initial step in the design of a converter is to determine the reaction
path by constructing an equilibrium conversion diagram. Such a
diagram is shown in Figure 1, for a typical feed gas composition of 8%
SO0, 13% O and 79% N The data required for the construction are
£ £ £
values for equilibirum constant, heats of formation and enthalpies of
the gaseous components. For the SO oxidation reaction:-
III - 2
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CONSULTING DIVISION
(PS03)
K = . - _ , — :rr - . . where P = component partial pressure
p (P^0) (p} 7
at one atmosphere total pressure ,„
_/SO3 Mols/Hr\x /Total Mols/Hr\
p \SC> Mols/Hry \O Mols/Hry
^ ^ ' N ^ X
Experimentally determined K values have been reported by Ross and
others. Table 1 lists calculated equilibrium conversions vs. temperature
for various converter feed gas mixtures, and for these a curve of
conversion vs. temperature is drawn.
Using a heat of reaction of 41, 500 BTU/Lb Mol (@ 820°F) and enthalpy
(2)
data , the adiabatic A T's at 100% conversion for various sulfur
burning gas mixtures were calculated and listed in Table 2.
The reaction path may be determined as follows: After plotting the
equilibrium conversion vs. temperature, a straight line is drawn
originating at 0% conversion and 820 F (the feed conditions) and
terminating at 100% conversion and 1, 222°F (820°F plus 402°F of
adiabatic temperature rise). Thus, the slope of the first catalytic
stage "operating" line is set by the adiabatic AT. The horizontal
lines represent interstage cooling of the reacting gas mixture. Since
the mixture heat capacity remains almost constant throughout, the slopes
of the operating lines for the following stages stay constant and the lines
are parallel. Thus, the reaction path is conveniently determined in a
graphical manner (Figure 1). Approaches to equilibrium are
(1) Ross L.W., Sulfur, 1966 No. 65, p. 37.
(2) Chemetron Corp. , Physical and Thermodynamic Properties
of Elements and Compounds, 1969.
Ill - 3
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FKiUKt 1
lOOt
90
(\! *
n =
I
T
5
I
t- u >
o=
— r
I
W
i
CAL: CLASS; 1:8 PLANT
900 1000
EQUILIBRIUM TEMPERATURE °F
1100
-------
TABLE 1
EQUILIBRIUM CONVERSIONS
Feed SO2,
Feed 02,
Mol % 4
Mol % 17
5
16
S00 + 1
6
15
/2 On = S00
P = 1
ATM
7
14
8
13
9
12
10
11
11
10
12
9
%
Conv.
99. 5
99. 0
98. 5
98. 0
97. 5
97.0
96. 5
96.0
95. 5
95. 0
90. 0
85.0
80.0
75.0
70. 0
65.0
60. 0
55. 0
50. 0
45. 0
o
Temperature F
759. 7
810.4
842. 3
866.0
885. 2
901.3
915.3
927. 7
939.0
949.2
1, 022.2
1, 072.3
1, 111.9
1, 146.3
1, 177.7
1, 207.2
1,235.9
1,264.4
1,293.2
1, 323.0
756.2
806.7
838.4
862.0
881.0
897.0
910. 9
923. 3
934. 5
944. 7
1, 017. 8
1, 067.2
1, 106. 7
1, 141.0
1, 172.2
1,201.7
1, 230.3
1,258.7
1, 287. 5
1, 317. 3
752. 3
802. 5
834. 0
857.4
876. 3
892. 2
906. 1
918.4
929. 5
939. 6
1, 012. 3
1, 061. 5
1, 100. 9
1, 135. 1
1, 166.2
1, 195.7
1, 224. 3
1, 252. 6
1,281.4
1, 311. 1
747. 9
797. 7
829. 0
852. 3
871. 0
886. 9
900. 6
912. 8
923. 8
933. 9
1,006. 2
1, 055.2
1, 094.4
1, 128. 5
1, 159. 6
1, 189. 1
1,217. 6
1,246. 0
1,274. 7
1, 304.4
742. 9
792. 3
823. 3
846.4
865.0
880. 7
894. 3
906. 5
917.4
927.4
999.3
1, 048. 0
1, 087. 1
1, 121. 1
1, 152. 2
1, 181.7
1, 210.2
1, 238. 6
1, 267. 3
1,297.0
736. 9
785. 8
816. 6
839.4
857. 9
873.4
887. 0
899. 0
909. 9
919. 3
991.2
1,039. 7
1,078. 1
1, 112. 1
1, 143. 9
1, 173. 3
1,201. 9
1,230. 3
1,259. 1
1, 288. 8
729. 7
778.0
808.4
831.0
849.3
864. 7
878. 1
890.0
900. 8
910. 6
981. 5
1, 029. 9
1,068. 9
1, 103. 0
1,134,2
1, 163.7
1, 192.4
1, 220. 9
1,249. 8
1, 279. 6
720. 5
768. 1
798. 1
820.4
838.4
853. 6
866. 9
878. 7
889. 3
899. 1
969. 6
1,017.9
1,057. 0
1, 091.2
1, 122. 6
1, 152.4
1, 181.3
1, 210. 1
1, 239. 1
1, 269.2
707. 6
754.4
783. 8
805. 8
823. 5
838. 5
851. 6
863.2
873. 8
883. 5
953.7
1, 002. 3
1, 041.8
1, 076. 5
1, 108.4
1, 138. 6
1, 168.0
1, 197. 1
1,226. 6
1,257.0
-------
TABLE 2
Feed SO2
Mol. %
Feed O
Mol. %
AT
oF
ADIABATIC TEMPERATURE RISE
AT 100% CONVERSION
4 5 6 7 8 9 10 11
17 16 15 14 13 12 11 10
210 260 308 355 402 452 491 534
12
9
577
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CONSULTING DIVISION
set at about 90% of the individual stage equilibrium conversion, depending
on the catalyst activity and quantity and any limitation of maximum
temperature imposed by the properties of the catalyst.
Figures 2a and 2b depict equilibrium conversion curves and the slopes
of the adiabatic temperature rise for gas mixtures ranging from 4% to
12% SO0 based on the air oxidation of sulfur.
£
Catalyst quantity requirements are determined by the reaction rate.
For the SO2 oxidation reaction a number of rate equations have been
reported in the literature . At Chemico a computer simulation of
the SO converter is based upon the rate equation as proposed by
(2)
Calderbank . The fact that a number of different rate equations
exist for the same reaction casts doubts upon the reliability of
calculated catalyst quantity requirements. A discussion on the merits
of one rate equation over another is outside the scope of this study;
however, care has been taken to use calculated results wherever
applicable on a relative basis.
(1) Honti G. , Annales du Genie Chimique, International Sulfur
Congress, Toulouse (1967), pp 206-214.
(2) Calderbank P. H. , Chemical Engineering Progress, 49(11),
pp. 585-590.
Ill - 4
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-------
100-
800
1000
1100
1300
.
•
-1
'•"a
i
•"i ~
_j
-
— .
3Z-SO
— f—
i
- ~t~
i
. .. .
i
^4_.
•
jt
-U
.
:"i
: 1
— \-
Fl«.
'"}
lEOUILIBRIU
- 1— j
..:-
- I
. J
KCK
[
I '
M CON
o-
900
.obo
1300
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CONSULTING DIVISION
Ideal Stage Conversion Limits
Preceding any attempts to design or modify a converter system, the
maximum conversion limits imposed by an ideal converter should be
recognized. An ideal converter implies 100% approach to equilibrium
conversion, in each stage and would require very large amounts of
catalyst and/or infinite retention time. This discussion will be limited
to three and four ideal stages of conversion which a re the actual
number of stages found in the majority of industrial converters.
Using the equilibrium conversion and adiabatic temperature rise data
given in Figures 2 (a and b) the ideal reaction path was determined in
the same manner as Figure 1, but continuing to the equilibrium, for
sulfur burning gases ranging from 4% SCX to 12% SO?, in all cases
the N_ content being 79%. This was done for four different types of
^j
ideal converters:
Type A
3 stages, all stage feed temperatures @ 820 F
Type B
3 stages, 820°F in @ stages 1 and 2, 770°F in
@ stage 3
Type C
4 stages, 820 F in @ stages 1 to 4
Type D
4
@ stage 4
4 stages, 820°F in @ stages 1 to 3, 770°F in
III - 5
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FIGURE 3
100
IDEAL CONV.
STAGE CURVES
95
789
% S02 IN FEED GAS
10
II
12
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CONSULTING DIVISION
The ideal conversion obtained was plotted on Figure 3, where curves A,
B, C and D represent the types of converter. The coordinates are
percentage conversion of SO- and percent SO,, in the reactor feed gas.
To expand the scope of Figure 3, curves of equal concentration of SO?
in the plant tail gas (ppm SO0) were superimposed. For example, for
LA
an 8% SO using a 4 stage low temperature converter (D) the maximum
Li
conversion is 99. 24% and the exit SO ppm is about 600.
£
The significance of Figure 3 is that it shows what can be done in any
converter system within the limitations imposed by operating conditions.
This will be discussed further in Part IV-C. The lowering of stage feed
temperature from 820 F to 770 F was done only for the last stage
because there would not be any significant conversion improvement if
the feed temperature was lowered for all the stages, and, from a heat
exchange view point, the last stage is the most practical place to lower
feed temperatures in an existing plant. 770 F is purely an arbitrary
temperature, in the actual case lower feed temperatures would be
chosen according to catalyst considerations.
It should be restressed that Figure 3 represents maximum conversions
under ideal conditions.
The Variation of Conversion Efficiency with Plant Capacity
Many sulfuric units are operated under process conditions other than
design in order to increase plant capacity. In sulfur burning plants
burning more sulfur without increasing air flow results in a higher
concentration SO9 gas mixture out of the sulfur furnace, the O0:SO0
z z ^
ratio is decreased and the net result is a reduction of the
III - 6
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CONSULTING DIVISION
conversion efficiency thus increasing SO emission levels. If blower
&
capacity permits, increased production may also be obtained without
reducing the O :SO ratio by increasing air flow at the same time as
2 2
the sulfur.
The possible effects were determined for a standard sulfur burning plant.
A capacity factor of 1. 0 was assigned to operation at the following design
characteristics:
8% SO sulfur burning
4 stage converter
SO? conversions after the four catalytic stages set
at 72%, 93%, 96. 8% and 98%
820 F feed temperature at all the stages
A main blower with 15% over capacity
Using the Chemico converter simulation program, catalyst quantities
were calculated for each stage of the above converter. The run was
repeated for feed SO concentrations of 7% and 9% using the same
amount of catalyst. Thus, the effect of just varying the feed sulfur
was determined, everythirg else being constant. The calculation was
repeated at each SO? concentration for maximum and minimum air
rates, these being 115% and 85% respectively of the design air rate.
The data was plotted on Figure 4.
From the plot of Figure 4 it is readily seen that conversion is a function
of plant throughput and feed SO concentration. For example, the
conversion of an 8% SO^ gas can be improved from 98 to about
98. 28% by reducing plant throughput alone, the respective capacity
III - 7
-------
O X
1
E IN U
KEUFFELa ESSCR CO.
CH|ART
APAq U.i(L FACTOR = 1.0 FOR .
VERSION
SOZ AND 98
7%. S02
DENTICAL CATALIST QUANTITIES
OR ALL CASES.
COMVERSION EFF
PLANT CAPAC
0.8
0.9
CAPACITY FACTOR
-------
CONSULTING DIVISION
factors being 1. 0 and 0. 852. However, if less sulfur is burned at
constant throughput such as the 7% SO at 100% design air rate level,
the conversion is 98.44% and the capacity 0. 879. This indicates that
at least for the given example, decreasing SO concentration is a
better means of control. The example is shown in Table 3.
Figure 4 applies only to sulfur burning plants. Wet gas plants are
less predictable due to the greater variety of feed gas concentrations
encountered, but the same principle applies.
Sulfuric Acid Mist
Sulfuric acid mist consists of small drops of sulfuric acid, usually over
90% concentration, formed in the vapor phase from water vapor and SO~.
O
Once formed it is extremely stable and is not readily separated or
absorbed. It is this stability that is of importance in sulfuric acid
plants and designs of these plants would be different if it were not for
the peculiar properties of this mist.
In sulfur based acid plants dry sulfur is burned in dry air and water
vapor is kept out of the plant. In wet gas plants, where the formation
of mist is inevitable in the wet purification section (as almost all SO
bearing gases will contain traces of SO ) this mist is removed by
o
electrostatic precipitators or special filters and the gas dried before
any further SO,, is formed. Only in the comparatively few plants,
O
usually based on H S, where the undried gas is reacted in the
converter, is mist formation deliberately permitted and in these
plants there is always special treatment of the tail gas to remove the
mist.
Ill - 8
-------
CONSULTING DIVISION
TABLE 3
EMISSION CONTROL
% SO9 in Feed
£i
Air Rate, % of Design
% Conversion
Capacity Factor
Exit ppm SO9
BY REDUCING
Base
Case
8
lign 100
98. 00
1. 0
1,813
PRODUCTION
Reduced
Throughput
8
85
98.28
0. 852
1, 560
Reduced
SO0 Content
7
100
98. 44
0. 879
1,232
-------
CONSULTING DIVISION
In spite of the precautions taken, some mist formation does take place
in most plants. This may result from the inadequate performance of the
drying tower or moisture in the sulfur, but the most common cause is
the presence of hydrocarbons in the sulfur which burn with it producing
water which will combine with the SO as the gas cools in the economizer
O
or absorption tower. This mist formation may be accentuated by sudden
chilling of the gas on cold surfaces, an effect sometimes produced by
rain on the gas duct. Such information as exists indicates this type of
mist consists of sulfuric acid drops of between 1 and 5 microns.
A most persistent form of this mist is produced in most oleum plants.
In these plants, oleum (i.e. sulfuric acid containing excess S(X in
O
solution) is produced in an preliminary absorption step before the main
absorption tower. Only part of the SO~ is absorbed and the gas leaving
O
the oleum tower still contains SO , and this is absorbed in the absorption
O
tower. In spite of this preliminary absorption, the stack gas is always
much more misty than when the oleum tower is bypassed. The mechanism
of this mist formation is not clearly understood but it has been established
that it is formed in the final absorption tower, not in the oleum tower.
The important fact from a pollution standpoint is that this mist consists
of very much finer (0. 2-3. 0 micron) particles than that present in the
normal mist produced in plants where oleum is not a product.
For plants producing 98% acid it has been reported that about 30% by
weight of the particles are smaller than 2 microns, while for oleum
plants 85-95% by weight of particles are smaller than 2 microns.
(1) E.P. Stastny, "Electrostatic Precipitation" - Chemical
Engineering Progress, Vol. 62, No. 4 - April 1966
III - 9
-------
CONSULTING DIVISION
Another cause of mist formation is the presence of nitrogen oxides in the
converted gas. This may result from the fixation of atmospheric nitrogen
in high temperature furnaces and the slightly misty stack of sulfur burning
plants was at one time thought to arise from this cause.
More commonly nitrogen oxides will result from nitrogen compounds in
the raw material used, spent acids from organic reaction being most
likely to produce them. Formation of nitrogen oxides can be avoided by
choosing the correct operating conditions for the reactor (decomposition
furnace, roaster, etc. ) in which they are formed. For instance, in the
decomposition of spent acid containing nitrogen compounds, operation of
the furnace at about 2, 000 F and a low oxygen content will ensure the
decomposition products do not contain more than 100 ppm of nitrogen
oxides.
Again, the exact mechanism of mist formation is something of a mystery
but it may result from the oxidation of residual SO9 by nitrogen oxides
^
(the chamber plant reactions) in the stack itself and in this case the
only satisfactory solution is to prevent the nitrogen oxide formation.
Several methods of removing mist are described elsewhere in the report.
Knitted mesh filters are the most commonly used (taking a pressure drop
of 2-3" W. G. ) and are satisfactory for all but the very fine mist from
oleum plants. In this case, the packed glass wool filter with a much
higher pressure drop (12" - 18" W. G. ) is necessary, as here we are
dealing with mist particles in the 0. 2 to 2. 0 micron range. Electro-
static mist preceipitators will remove almost all mists with a pressure
drop of < l" W. G. if properly chosen. Packed scrubbers will have little
effect on removing mist. High pressure drop (35"-40" W.G. ) venturi
scrubbers will remove all but the finer mist particles.
Ill - 10
-------
CONSULTING DIVISION
Acid Mist, SO and H SO . Vapor
-------
CONSULTING DIVISION
B. CLASSIFICATION OF SULFURIC ACID PLANTS
For purposes of the study sulfuric acid plants have been divided
into groups which tend to have the same types of emission
problems, and consequently, the same types of remedies will
be applicable to most plants in any one classification. Considera-
tion is also given to production cost which is utilized in Part V.
These classifications have been designated for existing plants:
1. 0 for chamber acid plants
1. 1 for sulfur burning contact plants with 3 conversion stages
1. 2 for sulfur burning contact plants with 4 conversion stages
1. 3 for "wet gas" contact plants with 3 conversion stages
1.4 for "wet gas" contact plants with 4 conversion stages
1. 5 for sulfuric acid concentrators
Each classification and its characteristics are more fully
described in the next few pages.
In order to determine the approximate number of plants in each
classification it was assumed that plants built through 1960
were 3 stage plants and those built after 1960 were 4 stage
plants. Although this is an arbitrary division, 1960 was the
time when the 4 stage conversion plant came into general use
in the United States and conversion was increased from 96%
to 98%.
Ill - 12
-------
CONSULTING DIVISION
Plant Classification 1.0
Chamber type acid plants, though they are gradually disappearing, are
included in a separate classification because their emissions are quite
different from the contact process plant. Most chamber plants are of
small capacity, ranging from 40 to a little over 100 short tons per day
of 100% H0SO. equivalent. The chamber process produces acid of
£ 4
about 78% which finds little use outside of acidulation of phosphate rock
to produce single superphosphate fertilizers. Most chamber plants are
located in the southeastern states, as are most of the large contact
plants which supply acid for production of more complex phosphatic
fertilizers.
Tail gas emissions from chamber plants are approximately as follows:-
Flow Rate 100-160 MSCF/ton of acid
(as 100% H SO )
^ 4
SO Content 1, 500-4, 000 ppm
Acid Mist Content 5-50 mg/SCF
NO Content 1, 000 ppm
NO Content 500 ppm
The chamber process is illustrated by Figure 5.
Presently operating chamber plants burn sulfur as raw material.
There are fewer than 40 remaining in the United States.
Ill - 13
-------
s
I
p
:
NITROGEN OXIDES
SULFUR
USED ON JOB I
BURNER
I I
GLOVER
, TOWE R
COOLER
78* H2S04
WATER
LEAD
CHAMBERS
62%H2S04
J
GAY-LUSSAC
TOWERS
NITROUS
VITRIOL
wurT bwufTiTTT
•o. I n*M* I
TAIL
GAS
ACID
PRODUCTS
LIST or rum
CHEMICAL CONSTRUCTION CORPORATION
CONSULTIMC. DCSKMMC AND COKntACTDK CMCINOltS
KW mm. H. T.. O.S.A.
PLANT CLASSIFICATION 1.0
SCHEMATIC FLOW DIAGRAM
CHAMBER PROCESS ACID PLANT
BSUCD FOH CONSTRUCTION
AUTHORIZATION NO.
0064 C
DRAWING NO.
-------
CONSULTING DIVISION
Plant Classification 1. 1
This classification, illustrated by Figure 6, includes sulfur burning contact
plants having three conversion stages. These plants, for the most part
built prior to 1960 in the United States, may produce various grades of
acid from 93% H SO . to oleum, or comb inations thereof.
L* *•
Typical operating characteristics of these plants are as follows when
operating at design conditions :-
SO in Converter Feed 7. 5 to 8. 5 Mol %
CA
Conversion of SO to SO 95 to 96%
Characteristics of the tail gas emission from these plants at design
conditions are as follows:-
sjc
Maximum Flow 91, 800 SCF per ton of acid
(as 100% H2SO4)
SO Content 3, 000 to 5, 000 ppm
& • .
Acid Mist 2 to 20 mg/SCF
SO Content 0.3 to 1.3 ppm ......
O
Oxygen 9 to 11% by volume
Water Nil
Inert Gas (N2, A, CO2,etc) Remainder
Temperature 150-180°F
Under any combination of SO strength in the converter feed gas
^
and conversion efficiency from the operating characteristics
shown above. This would be a normal design condition for a
tail gas scrubber.
Calculated from vapor pressure of SO over 98. 5% H SO. for
tj ^ T
given temperature range.
Ill - 14
-------
1
o
5s
:•
SULFUR*
BOILER
FEED •-
WATER
AIR
f
*• STEAM
SULFUR
FURNACE
BOILER
BOILER
ECONOMIZER
DRYING
TOWER
-*r
USED ON JOB I
CONVERTER
WITH
INTERCOOLERS
r
T OLEUM
_ _j_ TOWER (OPTIONAL)
I OLEUM.
P PRODUCT
TAIL
'GAS
ABSORPTION
TOWER
ACID
PRODUCTS
wurr MIMTTITTT
mo. {urnxm \
USTOf rAHTS
CHEMICAL CONSTRUCTION CORPORATION
CONUfLTTNC. MSICMIK AHO COKTWACTWC DNMCERI
mm raw. IL r.. U.&A.
PLANT CLASSIFICATION I. I
SCHEMATIC FLOW DIAGRAM OF
SULFUR BURNING PLANT
WITH 3 STAGE CONVERSION
0064 C
FIG.6
-------
CONSULTING DIVISION
Sulfur losses per ton of acid produced (as 100% H SO ) are as follows at
£t 4
design conditions:-
Tons of Sulfur
as SO. 0. 014 to 0. 017
£
as Mist when producing
99% acid 0. 002 maximum
as Mist when producing
oleums 0. 005 maximum
These plants were in many cases capable of producing acid at rates
significantly higher than design but at lower efficiency and with
consequently greater sulfur losses. This is due to design factors
included in the plant designs which would permit operation at higher
capacities. Often plants were designed to produce as much as 50%
excess capacity at a lower conversion efficiency, and with excess
pressure capability in the blower and additional catalyst space in the
converter to permit reaching either design capacity with dirty catalyst
or higher capacity by addition of catalyst.
This type of plant can take maximum advantage of either a tail gas
recovery process which returns recovered SO to the plant, or an
add-on dual absorption process, by operating at maximum production
rate and still keeping emissions within reasonable limitations after
inclusion of a control system.
Many older plants are congested and surrounded by other facilities
which may make addition of new equipment for emission control very
difficult.
Ill - 15
-------
CONSULTING DIVISION
Sulfur burning plants always have sufficient heat to produce steam in
excess of plant requirements for heating and mechanical drives.
The use of steam generated is usually dictated by adjacent facilities.
If the acid plant is associated with a wet process phosphoric acid
plant, much of the steam can be utilized on the concentration of
phosphoric acid. If the acid plant is associated wi th a refinery or
other process plant, excess steam can usually be used in the
appropriate steam header. In the case where excess steam has no
user available, driving a turbo generator can reduce plant power
requirements.
In calculations of control costs it has been assumed, to be consistent,
that essentially all steam is exported and all drives are electric.
The oleum system, shown dotted in Figure 6, is included only in
plants producing oleum grades. The production of oleum affects
only the acid mist emission from the plant, mist from oleum plants
being more finely divided than that from plants producing acid
grades at less than 99%, and requiring a different type of mist
control device for such a plant for effective control. In instances
where separate devices or systems are incorporated for SO9 control
&
and for mist control, the mis I control systems for acid and oleum
plants will be different. Tail gas treatment systems which control
both mist and SO would be less affected by the grades of products
^
produced.
Operating United States plants falling within this classification vary
in capacity from 50 tons per day to 4, 000 tons per day; however,
no single unit in these plants exceeds about 750 tons per day.
Ill - 16
-------
CONSULTING DIVISION
There are about 60 plants in this category producing over 7, 500, 000 T/Y
of acid with no oleum. The majority of these plants are located in the
gulf coast states and the middle west.
About 35 additional plants produce over 4, 000, 000 additional T/Y of
acid, including some oleum. Many of these plants are located in the
northeast and midwest within AQCRs.
Ill - 17
-------
CONSULTING DIVISION
Plant Classification 1.2
This type plant, illustrated by Figure 7, is a typical modern 4-stage
conversion sulfur burning acid plant representative of those built from
1960 to the present. These plants may produce a variety of acid
grades ranging from 93% H?SO to various oleum grades, or combina-
tions thereof.
Typical operating characteristics of these plants are as follows when
operating at design conditions:-
SO2 in converter feed 7. 5 to 8. 5 Mol %
Conversion of SO to SO 96 to 98%
Characteristics of the tail gas emission from these plants at design
conditions are as follows:-
Maximum Rate ' 90, 800 SCF per ton of acid
(as 100% H SO )
Z ~r
SO2 Content 1, 500 to 4, 000 ppm
Acid Mist 2 to 20 mg/SCF
SO3 Content 0.3-1. 3 ppm
Oxygen 9-11% by Volume
Water Nil
Inert Gas (N^ A, CO etc) Remainder
o o
Temperature 150 - 180 F
: Under any combination of SO strength in the converter feed
gas and conversion efficiency from the operating character-
istics shown above.
Ill - 18
-------
H
Is
• :
8
5S
SULFUR*
BOILER
FEED
WATER
AIR«
CONVERTER
WITH
INTERCOOLERS
r
-*• STEAM
OLEUM
I_TOWER(OPTIONAL)
r
•*--. i
OLEUM
PRODUCT
TAIL
'GAS
ABSORPTION
TOWER
ACID
PRODUCTS
USED ON JOB I
CHEMICAL CONSTRUCTION CORPORATION
CONSULTING. MStGNMC AND CONTRACTING CNGmCERS
PLANT CLASSIFICATION I. 2
SCHEMATIC FLOW DIAGRAM OF
SULFUR BURNING PLANT
WITH 4 STAGE CONVERSION
ISSUED FO« CONSTRUCTION
AUTHORIZATION NO.
0064 C
DRAWING NO.
FIG. 7
-------
CONSULTING DIVISION
Sulfur losses per ton of acid produced (as 100% H9SO ) are as follows at
^ Tt
design conditions:
Tons of Sulfur
As SO 0. 007 to 0.014
£i
As Mist
when producing 99% acid 0. 002 maximum
As Mist
when producing oleum 0. 005 maximum
The majority of these plants are probably being operated at or near their
design capacities today, and the newest and largest at 98% conversion.
Comments with respect to steam production and optional oleum
producing facilities included with the description of class 1. 1 apply
equally to class 1.2.
Operating U.S. plants in classification 1.2 gener ally have a capacity
of 250 T/D or more. The largest plants do not exceed 2, 000 tons
per day in a single train, though some plants have multiple units.
It is beyond this point where structural problems apparently outweigh
the cost advantage of a single train plant, using the conventional low
pressure process. There are over 40 plants of classification 1.2
which produce over 11, 000, 000 tons annually of acid. The
majority are located in the southeastern states outside of AQCRs.
Approximately 10% are oleum producers.
A number of plants are designed for additional capacity at reduced
efficiency with provisions for additional catalyst. These plants
could improve conversion rate and reduce sulfur emission by
III - 19
-------
CONSULTING DIVISION
addition of catalyst while continuing to operate at the basic design rate,
although the conversion improvement is limited, as shown in Part III A.
These plants are technically suited to add-on dual absorption or tail
gas recovery systems of most types. Most were originally built with
some form of mist control device to reduce the acid mist in the tail
gas, and the 2 mg/SCF mist level in the tail gas reflects plants so
equipped. The class 1. 2 plants are not likely to be as cramped for
space required for an emission control system as other class 1. 1
plants, although this remains a distinct problem. Finding space for
an additional 28' diameter absorber and 35' diameter converter with
attendant duct work and heat exchangers such as would be required
for a large plant will not be simple. From Part V it can be seen that
tail gas recovery processes are more attractive for larger plants
such as are encountered in class 1. 2.
Ill - 20
-------
CONSULTING DIVISION
Plant Classification 1. 3
Figure 8 illustrates schematically a typical "wet gas" sulfuric acid plant
with 3 stage conversion of the type included in classification 1. 3. These
3 stage plants were mostly built before 1960, and may produce various
grades of acid from 93% H SO to oleum using a variety of sulfur sources,
singularly or in combination. Sulfur sources include SO resulting from
£*
roasting of various copper, zinc and other ore concentrates, burning of
spent alkylation acid or H^S from refinery operations, roasting of iron
pyrites, recovery of SO» from copper converter and reverberate ry
LA
furnace flues, and a few others.
While these plants differ widely from each other in detail, they all lend
themselves to similar methods of emission control. All generally
require similar types of in -plant control systems, but different from
those suitable for sulfur burning plants, as well as generally larger
add-on systems for a given plant capacity because of the normally
larger quantities of gas to be handled and sulfur values to be recovered.
Typical operating characteristics of these plants when operating at
design conditions are given below for various feedstock: -
SO in Converter Conversion
Feedstock Feed - Mol % SO to
H2S 7 94 to 96
Pyrites 6. 5 to 7.5 94 to 96
Acid Sludge 6 to 8 94 to 96
Copper Converter Gas 3 to 7 90 to 95
Roaster Gas 5 to 7 94 to 96
III - 21
-------
l\
BOILER
FEED
WATER ,
SULFUR
SOURCE
AIR
PURIFICATION
UNIT
EXCHANGER
EXCHANGER
o-
DRYING
TOWER
©=
CONVERTER
WITH
INTERCOOLERS
f~
* STEAM (X)
r* * OLEUM
I i TOWER (OPTIONAL)
i r-L^ ,
I
1 OLEUM
!~ PRODUCT
C±J
TAIL
GAS
ABSORPTION
TOWER
ACID
PRODUCTS
USED ON JOB I
©INCLUDES COMBUSTION UNIT WHEN USING SLUDGE, PYRITE OR H2 S.
(/\) STEAM IS GENERATED ONLY WHEN BURNING SLUDGE OR H2 S OR
WHEN ROASTING PYRITE. NONE IS GENERATED WHEN USING A
PURIFICATION UNIT ONLY, AS WITH SMELTER GAS.
LOT OF NUT*
CHEMCAL CONSTRUCTION CORPORATION
OQMSULTMC. DOKNINC AND COKTItACTINC ENGINEERS
mtm TUB. m. r. U.B.A.
PLANT CLASSIFICATION 1.3
SCHEMATIC FLOW DIAGRAM
WET GAS PLANT
WITH 3 STAGE CONVERSION
BSUCD FDR CONSTRUCTIOtl
AimtOWZATlOM MO.
0064 C
FIG. 8
-------
CONSULTING DIVISION
Characteristics of the tail gas emissions from these plants may be expected
to fall in the following ranges:-
Feedstock
Maximum Rate
SCF/ton of Acid
(as 100% H2S04)
H2S
Pyrites
Acid Sludge
Copper Converter
Gas
Roaster Gas
100,000
109,000
119, 000
192,000
145,000
SO Content,
3,000 to 5,000
2,500 to 5,000
2, 500 to 4,000
2,000 to 10,000
2, 000 to 5, 000
Acid Mist
mg/SCF
Producing
99% Acid
2 to 20
2 to 20
2 to 20
2 to 20
2 to 20
Producing
Oleum
5 to 50
5 to 50
5 to 50
5 to 50
5 to 50
* Under any combination of SO strength in the converter feed gas
dt
and conversion efficiency from the operating characteristics
shown above. The high mist rates are encountered in plants
with no control devices.
With this type of plant the variation in the other components in the tail
gas varies so widely that any compositions given would be meaningless.
Sulfur losses per ton of acid produced (as 100% H?SO.) are as follows
at design conditions:-
Sulfur Loss, Tons
Feedstock
H2S
Pyrites
Acid Sludge
Copper Converter Gas
Roaster Gas
As SO2
0.014 to 0. 021
0. 014 to 0. 021
0.014 to 0.021
0. 017 to 0.036
0.014 to 0.021
As Acid Mist
Producing Producing
99% Acid Oleum
. 002 max. . 006 max.
. 002 max. . 006 max.
. 003 max. . 007 max.
. 004 max. . Oil max.
. 003 max. . 008 max.
III - 22
-------
CONSULTING DIVISION
Plants based on pyrites, H S, or acid sludge (spent acid) will have excess
heat available for steam production and in most cases will, in fact,
include waste heat boilers. Plants based on roaster or smelter gases
from metallurgical processes are not normally steam producers. The
steam produced may be used in the plant for driving the main blower
and occasionally for driving the blowers and pumps.
The steam system adopted on any plant will depend on factors outside
the acid plant. Thus, where an acid plant is part of a phosphoric acid
production unit, it will be found best to drive the blower with a back
pressure tubine and so provide low pressure steam for phosphoric
acid evaporation.
As with classification 1. 1 and 1. 2, economics have been calculated
on the basis of all electric drives for plant equipment, with a nominal
credit for steam generated. This has been done for comparison
purposes.
Oleum facilities are optional, and the comments made for classifica-
tion 1. 1 apply to classification 1. 3 as well.
Many plants of this type operate on combinations of feed stocks and
include sulfur as well as one or more of the feedstocks mentioned
above. These plants require that the gas be cooled and cleaned
before introduction into the converter system.
Except in the case of plants based on copper converter gas, most
methods of emission control can be applied. The cyclical nature of
III - 23
-------
CONSULTING DIVISION
copper converter operation makes the application of the dual absorption
process, or even careful converter control much more difficult.
Many plants of this type are located in congested metallurgical
complexes and systems with minimum space requirements may be
preferred.
Those locations with several units close together recovering acid from
smelters may favorably utilize several tail gas scrubbing units feeding
to a single recovery system.
Operating United States plants of this type range in size from about 100
to 1, 000 ST/D capacity. Nearly 60 plants produce about 7, 500, 000 tons
of acid annually. About 40% of these plants produce some oleum, with
most oleum producers being sludge burning operations. Locations are
scattered, with concentrations in petroleum refining areas of
California, Texas and Chicago. Others are scattered, principally in
mining areas of the western states and outside of AQCRs.
Ill - 24
-------
CONSULTING DIVISION
Plant Classification 1.4
This classification illustrated by figure 9, includes typical modern "wet
gas" sulfuric acid plants having 4 stages of conversion, typical of plants
built in the sixties. As with other classifications, these plants produce
a variety of product grades ranging from 93% acid through oleum, and
combinations of these products. Sulfur is derived from the same variety
of sources as described in classification 1. 3.
While these plants differ widely from each other in detail, they all
lend themselves to similar methods of emission control. All generally
require similar types of in plant control systems, but different from
those suitable for sulfur burning plants, as well as generally larger
add-on systems for a given plant capacity because of the normally
larger quantities of gas to be handled and sulfur quantities to be
recovered.
Typical operating characteristics of these plants when operating at
design conditions are given below for various feedstocks:-
SO in Converter Conversion
Feedstock Feed. Mol % SO9 to SO,,. %
" ^ O
H2S 6. 5 to 7. 5 95 to 98
Pyrites 6. 5 to 7. 5 95 to 98
Acid Sludge 6 to 8 95 to 98
Copper Converter Gas 3 to 7 94 to 98
Roaster Gas 5 to 7 95 to 98
Characteristics of the tail gas emissions from these plants may be
expected to fall in the following ranges: -
III - 25
-------
!=!
5 I
•
BOILER
FEED
WATER (
SULFUR
SOURCE'
AIR
PURIFICATION
UNIT
EXCHANGER
EXCHANGER
DRYING
TOWER
STEAM (A)
CONVERTER
WITH
INTERCOOLER5
r
~> OLEUM
i TOWER (OPTIONAL)
-L^—-,
, clj
OLEUM^
PRODUCT
_^
"* GAS
ABSORPTION
TOWER
ACID
PRODUCTS
Lt
tt)
w
USED ON JOB I
©INCLUDES COMBUSTION UNIT WHEN USING SLUDGE, PYRITE OR H2 S.
STEAM IS GENERATED ONLY WHEN BURNING SLUDGE OR H2 S OR
WHEN ROASTING PYRITE. NONE IS GENERATED WHEN USING A
PURIFICATION UNIT ONLY, AS WITH SMELTER GAS.
UST OF PARTS
CHEMICAL CONSTRUCTION CORPORATION
CONSULTING. DESIGNING AND CONTRACTING ENGINEERS
PLANT CLASSIFICATION 1.4
SCHEMATIC FLOW DIAGRAM
WET GAS PLANT
WITH 4 STAGE CONVERSION
ISSUED FOX CONSTRUCTION
AUTHOMZATIOM NO.
0064 C
DRAWING NO.
FIG.9
-------
CONSULTING DIVISION
Feedstock
H2S
Pyrites
Acid Sludge
Copper Converter
Gas
Roaster Gas
Maximum Rate
SCF/ton of Acid
(as 100% H^SO )
99,000
108,000
117, 500
184,000
143,000
SO Content,
ppm
1, 500 to 4,000
1, 500 to 4, 000
1,500 to 5,000
2,000 to 7, 000
1,000 to 4, 000
Acid Mist
Mg/SCF
Producing
99% Acid
2 to 20
2 to 20
2 to 20
2 to 20
2 to 20
Producing
Oleum
5 to 50
5 to 50 •
5 to 50
5 to 50
5 to 50
Under any combination of SO strength in the converter feed gas
^
and conversion efficiency taken from the operating characteristics
shown on the preceeding page. The higher mist rates are those
that would be encountered on plants with no mist control device.
Sulfur losses per ton of acid produced (as 100% H?SO ) are as follows at
design conditions:-
Sulfur Loss, Tons
Feedstock
H2S
Pyrites
Acid Sludge
Copper Converter Gas
Roaster Gas
As SO2
0. 007 to 0. 017
0.007 to 0.017
0. 007 to 0. 017
0. 014 to 0. 021
0. 007 to 0. 017
As Acid Mist
Producing Producing
99% Acid Oleum
. 002 max. . 005 max.
. 002 max. . 006 max.
. 003 max. . 006 max.
. 004 max. . 010 max.
. 003 max. . 008 max.
The comments regarding steam, oleum production, and economic
calculations for classification 1. 3 apply t-qually to class 1.4.
Many plants of this type operate on combinations of feed stocks, including
sulfur as well as one or more of the feedstocks mentioned above. These
III - 26
-------
CONSULTING DIVISION
plants require that the gas be cooled and cleaned before introduction into
the converter system. Within the same limitations as class 1. 3 most
emission control methods may be applied including the addition of a
second absorption stage, addition of catalyst as with classification 1.2,
plus recovery processes which remove SO SO and acid mist from
^ o
tail gases. Locations with smelter operations having several units or
with other emission sources may find advantage in using several
individual tail gas scrubbers contributing recovered sulfur compounds
to a central recovery system.
Plants in this classification range in capacity from about 150 T/D to
1, 600 T/D. These plants are relatively few, numbering about 20,
but produce about 4, 000, 000 tons of acid annually. Most are
connected with mining operations scattered in the western states.
Several are connected with refinery operations on the Louisiana-
Texas gulf coast. About 1/3 are oleum producers.
Ill - 27
-------
CONSULTING DIVISION
Plant Classification 1. 5
Two major types of sulfuric acid concentrators are in use:
Indirectly Heated Under Vacuum:
Operating under high vacuums water is evaporated via heating
the dilute spent acid in steam heated exchangers, the hot acid
is discharged into a flash chamber where flash evaporation
takes place and the overhead vapors consisting of water and
some H SO are liquified in a condenser. This type of
^ 4
operation does not have gaseous emission problems
(Mantius type). The.condenser water maybe slightly acidic.
Directly Heated Drum Concentrators:
This is a popular unit for large capacities and high concentra-
tions (illustrated by Figure 10). Counter-current contact of
a hot gas mixture and the weak acid in three separate drums
which represent stages of contact provides direct contact
heating to evaporate water. H_SO vapor formed in the high
^ 4
concentration stage is partly condensed in the following
stages. Prior to being discharged to the atmosphere the tail
gas is treated for final mist removal in a venturi scrubber;
many earlier plants used electrostct ic mist eliminators for
this purpose.
When operated under design conditions the H9SO. mist emission should
^j TC
not exceed 5 mgs H,,SO4/SCF, above which level a visible plume
persists. Mist emissions as high as 40-50 mgs/SCF have been re-
ported in the past, however, these have probably been from war time
III - 28
-------
AIR
HEATER
BLOWER
FUEL
WEAK ACID
CONCENTRATOR
DRUM
COOLER
DRUM
TAIL
GAS
SCRUBBER
&
SEPARATOR
.SCRUBBER ACID
PUMP
CONCENTRATED
PRODUCT ACID
!=!
USED ON JOB |
LIST OF PARTS
CHEMICAL CONSTRUCTION CORPORATION
CONSULTING. DESIGNING AND CONTRACTING ENGINEERS
HEW YOK. N. 1.. U.C.A.
PLANT CLASSIFICATION 1.5
SCHEMATIC FLOW DIAGRAM
SULFUR 1C ACID CONCENTRATOR
ISSUED FOR CONSTRUCTION DATE
AUTHORIZATION NO.
0064 C
ORAWING NO.
FIG.IO
P
-------
CONSULTING DIVISION
ordnance works which very likely were operating under overload conditions
with malfunctioning electrostatic mist separators.
Stack gas H SO mist loading is a function of:-
£ *
collection efficiency of venturi scrubber
high stage drum vapor pressure
air rate through the high stage
liquid entrainment from cooler drum
The main function of concentrators is to remove water, and the exit
gases contain large quantities of water vapor which, under certain
weather conditions, condense to form a visible fog. When concentra-
ting nitration spent acid, impurities in the form of nitric and nitrous
acids, toluene and nitrobodies may be introduced into the concentrator
and distilled in the cooler drum resulting with a redish brown stack
plume which also has an odor. Some SO will often be formed in the
^
concentrator by the reduction of sulfuric acid by organic compounds.
No data of any value is available and SO emission is not generally a
^
problem. Both SO0 emissions from this cause and acid mist will in-
^
crease at high concentrations, and this type of equipment is not
suitable for producing acid of a higher strength than 95-96%.
Ill - 29
-------
CONSULTING DIVISION
Plant Class if icaticns 2. 1. 2.2, 2.3. 2.4. 2.5
These classifications refer to future plants of the same types as discussed
on the previous pages. They are considered separately only because the
construction of a plant and control system simultaneously often produces
different economic results.
Class 2. 1, a 3-stage sulfur burning plant which is not presently being
built may return to consideration if built in conjunction with a control
system. It is quite possible that the trend to higher conversion of SC*
^
to SO,, in the converter may be reversed if a good method of recovering
O
and recycling SO from the stack is developed. Thus a plant incorporat-
^
ing a 3-stage converter operating with an SO concentration of 10-12%
^
and a conversion of 90-95% would represent a considerable capital cost
saving over a modern 98% conversion plant. This capital cost saving
would then contribute to the cost of the emission control plant designed
to recover the unconverted SO and return it to the plant inlet. At the
&
present time a development of this kind represents the most likely
approach to an overall 100% conversion SO~ to acid.
Class 2. 2 is a 4-stage sulfur burning plant of design similar to those
presently being built. This is still the most popular plant but future
plants may be of this type, arranged to include a ta 1 gas recovery
system, in which case they would be designed for maximum production
regardless of conversion, and would recover SO? from tail gas for
recycle. They might possibly be arranged to add processes 1. 2. 2 or
1.2.1 at a future 11 me it' emissions had not been specified. Of course,
the use of a new dual absorption plant (1. 1. 0) is the other
alternative.
Ill - 30
-------
CONSULTING DIVISION
Classes 2. 3 and 2. 4 are new 3-stage and 4-stage "wet gas" plants,
respectively. The comments on 2. 1 and 2.2 above are equally
applicable to these classifications, except that use of dual
absorption would be greatly restricted as discussed in Parts IV and
V.
Class 2. 5 is a new concentrator, probably identical to those in
existence in class 1. 5.
Ill - 31
-------
CONSULTING DIVISION
Acid Production Cost
The cost of acid production for plants of classifications 1. 0, 1. 1, 1. 2,
1. 3 and 1. 4 have been calculated as a basis for determination of
"Control Cost" in Part V. The acid production cost is not intended to
represent actual cost for any plant, but to provide a basis for control
cost only, since unit costs used are the same before and after inclusion
of a control system, and all processes are compared on the same
basis. Changes in unit costs could conceivably alter the relative merits
of the processes to some extent.
In determining operating costs the following conversion rates were
assumed:-
Plant Classification 1. 0 96. 5%
Plant Classification 1. 1 95
Plant Classification 1. 2 96
Plant Classification 1. 3 95. 8
Plant Classification 1. 4 96.8
The emission levels for class 1. 1 and 1. 2 were selected as typical for
plants producing at maximum rate. The levels for 1. 3 and 1. 4 also
fall within the ranges for these plants, however, these specific rates
were selected to simplify calculations of control costs in Part V.
Unit costs selected for raw material and utilities are as follows:-
Sulfur $25 per short ton
Sulfur Value in Any Other Form
(i.e. sludge, smelter gas, etr.) Zero
Electric Power $. 01 per KWH
Cooling Water $. 01 per short ton
Process Water $. 02 pers hort ton
Boiler Feed Water $. 05 per short ton
Steam $. 60 per short ton
III - 32
-------
CONSULTING DIVISION
Operating labor requirements for sulfur burning contact plants have been
assumed to be one man per shift, plus part time supervision equivalent
to 1/3 of a man per shift. This is not true for all plants, but is typical
of the majority, since most acid plants are associated with other
operations and may share some services. Operators have been charged
at $6 per hour and supervisors at $8 per hour. Chamber plants, most of
which are connected with small operations in the southeast where labor
costs are generally lower and plants are older and less automated and
may require more labor. In this case we have used the equivalent of
2-1/4 men per shift at $4 per hour.
Maintenance for contact plants has been assumed to be approximately
4% of the capital investment per year, including materials and labor.
For chamber plants, due to age and type of construction, 8% has been
used. Overhead is assumed to be 100% of the labor component of
maintenance plus operations, or approximately 70% of the sum of
operations and maintenance.
Depreciation is on a 10 year, straight line basis, and interest is taken
as 7-1/2% of investment per year. Since plants in classification 1. 0,
1. 1 and 1. 3 are assumed to be pre-1960, and consequently over 10
years old, no operating cost is charged for depreciation and interest
in these classifications.
Taxes and insurance are assumed to be 1 -1/2% of the original invest-
ment per year, except in the case oi' chamber plants where 1% has
been us ed.
Ill - 33
-------
CONSULTING DIVISION
The capital costs upon which maintenance, depreciation, taxes and
insurance are based are estimated typical single train battery limits
plant costs in the United States. Battery limits, for this purpose,
includes the erected cost, less land, of the equipment shown on
Figures 5 through 10 illustrating the various plant classifications.
For 1. 3 and 1. 4, a smelter gas plant has been us ed as typical.
Figure 11 shows approximate investment requirements upon which
those portions of operating cost relating to initial investment are
based. No investment difference is shown between 3 and 4-stage plants
of the same type, since design improvements approximately offset
increased costs for a number of years.
Figure 12 gives the acid production cost for various types of single
unit plants from 50 to 1, 500 T/D capacity based upon these para-
meters. Tables in the appendix show the basis of these curves.
These costs are the basis for calculating control costs in Part V.
No production cost is given for concentrators, since a wide variety
of capacities is possible with any one plant, capacity of a unit being
determined by water removed, not the quantity of acid produced.
Ill - 34
-------
•P-OG^BH ••v9'7!
EUFFEL & ESSER CO. KOI III II.1.1.
3 CYCLES X 70 DIVISIONS
10
50
IOO
200 500
SULFURIC ACID PLANT CAPACITY, ST/0
1000
2000
-------
1C
59--;
KEUFFEL ft ESSER CO. «»I III 0.1.A.
> CYCLES X 70 DIVISIONS
10
50
IOO 200
SULFURIC ACID
500
PLANT CAPACITY, ST/D
1000
2000
-------
CONSULTING DIVISION
C. CENSUS OF SULFURIC ACID PLANTS
The census, which appears in Tables 4, 5 and 6, has been prepared
as a tool to help determine the importance of various processes by
determining the number of potential possible applications in the
United States. The census is not represented as absolutely
accurate or complete, since it is not based on a direct survey of
acid manufacturers, but upon published data and in-house
knowledge.
The census is divided into three parts; Table 4 lists chamber
acid plants, Table 5 contact acid plants and Table 6 sulfuric
acid drum type concentrators. Vacuum type concentrators have
not been included, since they present no emission problem and
require no consideration in this study.
The census is arranged geographically by states, listing each
plant. Annual capacity is based upon approximately 330 operating
days per year. Although the on-stream factor for most plants is
higher than 330 days per year, all plants are not operating at full
capacity at all times, thus 330 days equivalent is not an unreal-
istic figure.
The terms "unit", "plant" and "establishment" as used in this
census require definition.
A unit may be considered as an individual H SO production
£t *
train, capable of independent operation to produce one or more
grades of H^SO from one or more raw materials.
Ill - 35
-------
CONSULTING DIVISION
A plant is one or more units built at the same time and place. For
example, Continental Oil at Pierce, Florida is a 2, 000 T/D plant (Table
5) which consists of two - 1, 000 T/D units in parallel, built simultaneously.
An establishment denotes one or more plants built and operated by one
company at one location. An example is Valley Nitrogen at Helm,
California, which includes 200, 300 and 600 ton plants built at different
times, but at the same location for the same producer. For plants
built after 1954, we have attempted to list each plant, but prior to 1954
have not attempted to differentiate between a plant and an establishment.
For example, Cities Service Co. at Isabella, Tennessee (Table 5) is
listed as a plant, but this is very likely more than one plant, judging by
the capacity and date built. Where a range of years is given before
1954, the reason often is that an establishment consists of two or more
plants built at various times within the given span of years.
For Table 5, the column headed "Principal Raw Materials" differentiates
between sulfur burning plants (classifications 1. 1 and 1. 2) and wet gas
plants (classifications 1. 3 and 1. 4). Sulfur burning plants list only
sulfur as a raw material. Other plants, even though they may burn
some sulfur, are wet gas plants, since their emission characteristics
and selection of control methods will be determined by the non-sulfur
raw material(s).
The column labled "Highest Concentration Product" on Table 5 lists
only 2 categories, since these determine the emission characteristics.
An oleum plant may produce one or more oleum grades, and may also
produce 98 or 93% acid, but as long as oleum is prodiced this fact
III - 36
-------
CONSULTING DIVISION
governs the emission characteristics of the plant. Plants producing acid
only below 99% H SO have essentially the same emission problems,
regardless of the grades produced.
Under the heading "Air Quality Control Region" is listed the central city
of one of the first 57 Air Quality Control Regions selected by the
National Air Pollution Control Administration (NAPCA).
If the geographic limits of the AQCRs have not yet been designated, we
have assumed that the Standard Metropolitan Statistical Area (SMSA)
will coincide with the AQCR. When a plant location falls within the
AQCR (or equivalent SMSA), the fact is noted in this column. The
first 57 AQCRs are listed on the following page.
Ill - 37
-------
CONSULTING DIVISION
1. Washington, D.C. 30.
2. New York* 31.
3. Chicago* 32.
4. Philadelphia* 33.
5. Denver* 34.
6. Los Angeles* 35.
7. St. Louis* 36.
8. Boston* 37.
9. Cincinnati* 38.
10. San Francisco* 39.
11. Cleveland* 40.
12. Pittsburgh* 41.
13. Buffalo* 42.
14. Kansas City* 43.
15. Detroit* 44.
16. Baltimore* 45.
17. Hartford* 46.
18. Indianapolis* 47.
19. Minneapolis-St. Paul* 48.
20. Milwaukee* 49.
21. Providence* 50.
22. Seattle-Tacoma* 51.
23. Louisville* 52.
24. Dayton* 53.
25. Phoenix 54.
26. Houston* 55.
27. Dallas-Ft. Worth* 56.
28. San Antonio* 57.
29. Birmingham
Toledo
Steubenville-Wierton-Wheeling*
Chattannooga
Atlanta
Memphis
Portland, Oregon
Salt Lake City
New Orleans
Miami
Oklahoma City
Omaha
Honolulu
Beaumont-Port Arthur
Charlotte, N.C.
Portland, Maine
Albuquerque
Lawrence-Lowell-Manchester
El Paso
Las Vegas
Fargo-Moorehead
Boise
Billings
Sioux Falls
Cheyenne
Anchorage
Burlington
San Juan
Virgin Islands
Denotes those areas for which the AQCRs have been designated
as of March 1, 1970.
Ill - 38
-------
SULFUR1C ACID PLANT CENSUS
TABLE 4
State Company
Alabama Standard Chemical
Home Guano Co.
Mobil Chem. Co.
Florida Wilson Toomer Fert. Co.
Continental Oil Co. /Agrico. Chem.
Wilson Toomer Fert. Co.
Georgia Southern States Phosphate Fert.
Mobil Chem. Co.
Pelham Phos. Co.
F. S. Royster Guano Co.
Armour Agr. Chemical Co.
Armour Agr. Chemical Co.
Columbia Nitrogen Corp.
Continental Oil Co. /Agrico Chem.
Cotton States Fertilizer Co.
Georgia Fert. Co.
Mobil Chem. Co.
Illinois Armour Agr. Chemical Co.
Continental Oil Co. /Agrico Chem.
Continental Oil Co. /Agrico Chem.
Kerr McGee Chem. Corp.
F. S. Royster Guano Co.
Continental Oil Co. /Agrico Chem.
Mississippi Inter Min. & Chem. Corp.
N. Carolina Continental Oil Co. /Agrico Chem.
S. Carolina Mobil Chem. Co.
Planters Fert. Phosphate Co.
F. S. Royster Guano Co.
Anderson Fertilizer Co.
Continental Oil Co. /Agrico Chem.
Continental Oil Co. /Agrico Chem.
Inter Min. & Chem. Corp.
Mobil Chem. Co.
Mobil Chem. Co.
F. S. Royster Guano Co.
American Agr.
W. R. Grace & Co.
Total - 37 Plants Producing
NOTES- Total Within AQCR- 6 Plants Producing
(1) AQCR not yet designated; plant located within SMSA.
(2) Where pre 1954 is given, exact date was not available.
CHAMBER PROCESS ACID PLANTS
City
Troy
Do than
Mobile
Cottondale
Pensacola
Jacksonville
Savannah
Savannah
Pelham
Athens
Albany
Columbus
Moultrie
Savannah
Macon
Valdosta
Rome
Chicago Hgts.
Fulton
Humboldt
Baltimore
Baltimore
Baltimore
Tupelo
Greensboro
Charleston
Charleston
Charleston
Anderson
Charleston
Columbia
Spartanburg
Memphis
Richmond
Norfolk
Alexandria
Norfolk
Annual
Air Quality Capacity
Control Region Short Tons
17,000
13,500
17,000
15,000
14,000
40,000
32,000
20,000
25,000
25,000
20,000
18,000
20,600
20,000
16,000
20,000
18,000
Chicago 35, 000
16,000
25,000
Baltimore 105, 000
Baltimore 40, 000
Baltimore 34, 000
18,000
21,000
18,000
25,000
12,000
17,000
20,000
11,000
20,000
Memphis'1' 18,000
35,000
22,000
National Capital 20, 000
22,000
Daily Capacity
Short Tons
50
40
50
45
40
120
100
60
70
70
60
50
60
60
45
60
50
100
45
70
300
120
100
50
60
50
70
35
50
60
35
60
50
100
65
60
65
Year(2)
Built' '
Pre 1954
11
"
1950
Pre 1954
1946
1917
1900
1912
Pre 1954
"
"
"
11
"
11
11
Pre 1954
"
Pre 1954
1917
Pre 1954
ii
Pre 1954
Pre 1954
1900
Pre 1954
"
"
n
"
"
1903
1912
Pre 1954
11
11
Principal
Raw Materials
Sulfur
M
it
Sulfur
"
"
Sulfur
"
n
"
"
"
"
11
M
"
"
Sulfur
"
Sulfur
Sulfur
it
"
Sulfur
Sulfur
Sulfur
"
n
"
n
"
11
Sulfur
Sulfur
11
"
"
Highest
Concentration
Product
<78% Acid
"
n
<78% Acid
11
n
< 7 8% Acid
"
it
n
"
n
M
"
"
"
11
< 78% Acid
M
<78% Acid
<78% Acid
"
11
< 78% Acid
< 78% Acid
< 78% Acid
n
11
"
n
ti
"
< 78% Acid
< 78% Acid
ii
"
885, 100 Short Tons/Yr.
262, 000 Short Tons/Yr.
-------
SULFURIC ACID PLANT CENSUS
State
Alabama
Arizona
Arkansas
California
Colorado
Delaware
Mobil Chem. Co.
American Cyanamid Co.
Mobil Chem. Co.
DuPont
Reichhold Chem. Inc.
Stauffer Chem. Co.
Arizona Agrochemical Corp.
Bagdad Copper Corp.
Phelps Dodge Corp.
Phelps Dodge Corp.
Kennecott Copper Corp.
Monsanto Co.
Arkla Chemical Corp.
Olin
Allied Chemical Corp.
Occidental Petroleum Corp.
Valley Nitrogen Prod. Inc.
Valley Nitrogen Prod. Inc.
Valley Nitrogen Prod. Inc.
AFC Inc.
Monsanto Co.
American Smelting & Refining
Allied Chemical Corp.
Stauffer Chem. Co.
Allied Chemical Corp.
Allied Chemical Corp.
Union Oil Co. of California
Stauffer Chem. Co.
Stauffer Chem. Co.
Stauffer Chem. Co.
Union Carbide Corp.
Allied Chemical Corp.
Allied Chemical Corp.
TABLE 5
CONTACT PROCESS ACID PLANTS
City
Birmingham
Mobile
Do than
Mineral Springs
Tuscaloosa
LeMoyne
Chandler
Bagdad
Morenci
Morenci
Ray
ElDorado
Helena
N. Little Rock
Nichols
Lathrop
Helm
Helm
Helm
Edison
Avon
Selby
El Segundo
Dominguez
Richmond
Richmond
Los Angeles
Richmond
Vernon
Martinez
Uravan
Denver
N. Claymont
Air Quality
Control Region
Birmingham
---
Phoenix
---
San Francisco Bay
San Francisco Bay
San Francisco Bay
Los Angeles
Los Angeles
San Francisco Bay
San Francisco Bay
Los Angeles
San Francisco Bay
Los Angeles
San Francisco Bay
Denver
Philadelphia
Annual
Capacity
Short Tons
26,000
28,000
26,000
21,000
52,000
140,000
28,000
60, 000
210,000
59,500
262,000
132.000
210,000
87,000
120,000
245.000
70,000
105,000
210,000
67, 500
105,000
15,000
140,000
330,000
65,000
105,000
113,000
175,000
105,000
297,500
60,000
50,000
350,000
Daily
Capacity
Short Tons
70
75
70
60
150
400
85
175
600
175
750
375
600
250
350
700
200
300
600
200
300
50
400
650
200
300
325
500
300
850
175
150
1,000
1938
1947
1966
Pre 1954
1956
1956
1959
1961
1965
1968
1968
Pre 1954
1967
1947
Pre 1954
1957
1959
1963
1965
1967
1953
Pre 1954
Pre 1954
Pre 1954
1943
1955
1960
Pre 1954
Pre 1954
1969
1960-65
Pre 1954
Pre 1954
Principal Raw Materials
Sulfur
Sulfur
ii
Cu Smelter Gas
n it ti
ii n it
Sulfur
Sulfur & Hydrogen Sulfide
Sulfur
Sludge & Hydrogen Sulfide
Smelter Gas
Sludge & Hydrogen Sulfide
Sulfur
Sulfur
Pyrites
Sludge + Pyrites
Highest
Concentration
Product
<99% Acid
Oleum
n
<99% Acid
Oleum
<99% Acid
<99% Acid
Oleum
<99% Acid
Oleum
<99% Acid
Oleum
<99% Acid
Oleum
Oleum
-------
TABLE 5 - PAGE 2
Mobil Chem. Co.
American Cyanamid Co.
W. R. Grace & Co.
Inter. Min. & Chem. Corp.
Swift & Co.
Mobil Chem. Co.
American Cyanamid Co.
Cities Service Co. Inc.
Cities Service Co. Inc.
Cities Service Co. Inc.
Cities Service Co. Inc.
W. R. Grace & Co.
F. S. Royster Guano Co.
Mobil Chem. Co.
American Cyanamid Co.
Chemical Inc.
Chemical Inc.
Inter. Min. & Chem. Corp.
Chemical Inc.
Armour Agr. Chemical Co.
Armour Agr. Chemical Co.
Chemical Inc.
Continental Oil Co. /Agrico Chem.
Borden Chem. Co. /Smith Douglas
Central Phosphates Inc.
Farmland Ind. Inc.
W. R. Grace & Co.
Occidental Petroleum Corp.
Kaiser Agr. Chem. Company
American Cyanamid Co.
American Cyanamid Co.
Minerals & Chem. /Philipp Corp.
Cities Service Co. Inc.
Standard Oil Co. of California
J. R. Simplot Co.
J. R. Simplot Co.
Bunker Hill Co.
Bunker Hill Co.
Savannah N.
Savannah
Savannah
Attapulgas
Augusta
Honolulu
Pocatello
Pocatello
Kellogg
Kellogg
Annaul
Air Quality Capacity
Control Region Short Tons
110,000
320,000
230,000
210,000
315,000
200,000
260,000
300,000
300,000
300,000
300,000
230,000
385,000
225,000
50,000
315,000
210,000
140,000
315,000
520,000
280,000
315.000
700,000
490,000
600,000
550,000
365,000
700,000
35,000
160,000
85,000
36,000
131,200
Daily
Capacity
Short Tons
300
900
700
600
900
600
750
900
900
900
900
700
1, 100
650
150
900
600
400
900
1,500
800
900
2.000
1,400
1,700
1,570
1, 100
2,000
100
450
250
100
375
BU><3>
Pre 1954
Pre 1954
Pre 1954
Pre 1954
1948
1955-59
1955
1955-59
1955-59
1955-59
1955-59
1955-59
1960-65
1960-65
1960
1960-65
1960-65
1960-65
1962
1963
1964
1964
1964
1966
1966
1966
1966
1966
1952
1953
1956
1956
1967
Honolulu
(1)
40,000
225,000
420,000
90, 000
120,000
115
650
1.200
250
350
1960-65
1959
1966
1954
1966
Principal Raw Materials
Sulfur
Highest
Concentration
Product
<99% Acid
Sulfur
Sludge
Sulfur
Zn Smelter Gas
<99% Acid
<99% Acid
<99% Acid
-------
TABLE 5 - PAGE 3
State
Illinois
Indiana
Iowa
Allied Chemical Corp.
Swift & Co.
Borden Chem. Co. /Smith Douglas
National Distillers Chem. Corp.
American Zinc Co.
Hooker Chem. Corp.
Wilson Co. Inc.
Charles Pfizer Co. Inc.
American Zinc Co.
Monsanto Co.
New Jersey Zinc Co.
Allied Chemical Corp.
Olin
American Cyanamid Co.
Monsanto Co.
Stauffer Chem. Co.
DuPont
Stauffer Chem. Co.
Marion Mfg. Co.
Inter. Min. + Chem. Corp.
Sinclair Petrochemicals Inc.
National Distillers Chem. Corp.
Eagle Picher Co.
National Distillers Chem. Corp.
DuPont
Pennsalt Chem. Corp.
Olin
Allied Chemical Corp.
American Cyanamid Co.
Hooker Chem. Corp.
Allied Chemical Corp.
Freeport Sulphur Co.
Stauffer Chem. Co.
Cities Service Co. Inc.
DuPont
Bethlehem Steel Corp.
Olin
Olin
Olin
W.'R. Grace & Co.
City
Chicago
Calumet City
Streator
Tuscola
Sauget
Marseilles
Elwood
East St. Louis
East St. Louis
Monsanto
Depue
East St. Louis
Joliet
Joliet
Monsanto
Hammond
East Chicago
Hammond
Indianapolis
Mason City
Ft. Madison
Dubuque
Galena
DeSoto
Wurtland
Calvert City
Bossier City
Baton Rouge
Fortier
Taft
Geismar
Convent
Baton Rouge
Lake Charles
Bumside
Sparrows Pt.
Baltimore
Baltimore
Baltimore
Baltimore
A ir Quality
Control Region
Chicago
Chicago
—
..-
Chicago
St. Louis
St. Louis
St. Louis
St. Louis
Chicago
Chicago
St. Louis
Chicago
Chicago
Chicago
Indianapolis
---
Kansas City
---
New Orleans
Baltimore
Baltimore
Baltimore
Baltimore
Baltimore
Annual
Capacity
Short Tons
130,000
35,000
43,000
175,000
140, 000
240,000
210,000
6,000
154,000
234,000
420, 000
180,000
350, 000
50, 000
140,000
140, 000
325, 000
165,000
42,000
25,000
525,000
52, 000
155, 000
88,000
210,000
44, 000
70,000
87,000
35,000
510,000
525,000
1,680,000
560, 000
149,000
525,000
87,000
105,000
70, 000
175,000
140, 000
DaUy
Capacity
Short Tons
400
100
125
500
400
700
600
18
450
675
1,200
500
1,000
150
400
400
950
500
125
70
1,500
150
450
250
600
125
200
250
100
1,500
1,500
4,800
1,600
450
1,500
250
300
200
500
400
Year.-.. .
Built
Pre 1954
1947
1951
1953
1960-65
1962
Pre 1954
Pre 1954
1967
Pre 1954
1967
1928
1942
1954
1955
1929
Pre 1954
1957
1947
Pre 1954
1968
1943
1954
1943
Pre 1954
1948
1929
1954
1960-65
1965
1967
1968
1969
1943
1967
1953
1943
1941
1949
1960-65
Principal Raw Material
Sulfur
"
"
"
n
"
Sulfur + Sludge
Ferrous Sulfate
Zn Smelter Gas
Sulfur
Zn Smelter Gas + Sulfur
Sulfur
n
"
Sludge + Sulfur
Zn Smelter Gas + Sludge
Sludge + Sulfur
Sludge + Sulfur
Sulfur
n
"
Sulfur + Zn Smelter Gas
Sulfur
Sulfur
"
Sulfur
"
"
11
"
"
Sulfur + Sludge
Sludge + Hydrogen Sulfide
Sulfur + Sludge
Pyrites + Hydrogen Sulfide
Sulfur
11
M
"
Highest
Concentration
Product
<99% Acid
II
II
II
II
II
Oleum
<99% Acid
"
Oleum
<99% Acid
Oleum
"
"
"
Oleum
"
11
"
<99% Acid
"
Oleum
<99% Acid
Oleum
Oleum
n
<99% Acid
"
11
"
"
"
Oleum
<99% Acid
Oleum
<99% Acid
Oleum
n
11
IT
-------
TABLE 5 - PAGE 4
State
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nevada
New Jersey
New Mexico
New York
N. Carolina
Monsanto Co.
W. R. Grace & Co.
American Cyanamid Co.
Continental Oil Co. /Agrico Chem.
Allied Chemical Corp.
North Star Chem. Inc.
Coastal Chem. Corp.
Missouri Lead Smelting Co.
St. Joseph Lead
W. R. Grace & Co.
National Lead Co.
National Lead Co.
National Lead Co.
Anaconda Co.
Anaconda
La Place Chem. Co.
National Lead Co.
National Lead Co.
National Lead Co.
National Lead Co.
Olin
Allied Chemical Corp.
Allied Chemical Corp.
DuPont
DuPont
DuPont
American Cyanamid Co.
American Cyanamid Co.
Essex Chem Corp. /Chems. Div.
Kerr McGee Chem. Corp.
Climax Chemical Co.
Allied Chemical Corp.
Eastman Kodak Co.
Mobil Chem. Co.
Swift Co.
Acme Chemical
Texas Gulf Sulphur Co.
Armour Agr. Chemical Co.
City
Everett
Detroit
Kalamazoo
Bay City
Detroit
Pine Bend
Pascagoula
Salem
Herculaneum
Joplin
St. Louis
St. Louis
St. Louis
Anaconda
Yerington
Edison
Sayreville
Sayreville
Sayreville
Sayreville
Paulsboro
Elizabeth
Elizabeth
Gibbstown
Linden
Deepwater
Warners
Bound Brook
Newark
Grants
Hobbs
Buffalo
Rochester
Wilmington
Wilmington
Acme
Lee Creek
Wilmington
Air Quality
Control Region
Boston
Detro it
Detroit
Minneapolis -St. Paul
---
St. Louis
St. Louis
St. Louis
St. Louis
---
---
N.Y. -N.J. -Conn.
N. Y.-N. J. -Conn.
N.Y. -N.J. -Conn.
N.Y. -N.J. -Conn.
N. Y.-N. J. -Conn.
Philadelphia
N.Y. -N.J. -Conn.
N.Y. -N.J. -Conn.
Philadelphia
N.Y. -N.J. -Conn.
Philadelphia
N.Y. -N.J. -Conn.
N.Y. -N.J. -Conn.
N.Y. -N.J. -Conn.
- —
Niagara Frontier
---
...
Annual
Capacity
Short Tons
105,000
35,000
25,000
35,000
210,000
115,000
260,000
70,000
119,000
70,000
70,000
160, 000
160,000
155,000
130,000
70,000
105,000
105,000
160,000
160,000
300,000
200,000
220,000
100,000
300,000
120,000
197,000
64,000
180,000
140,000
53,000
195,000
7,000
25,000
50,000
55.000
1.067,500
70,000
Daily
Capacity
Short Tons
300
100
70
100
600
330
750
200
350
200
200
450
450
450
400
200
300
300
450
450
850
600
600
300
850
350
550
200
500
400
150
550
20
70
150
170
3,050
200
Year(2)(3)
Built1 "'
1969
Pre 1954
1947
1957
1941
1959
1958
1967
1969
1960-65
1945
1950
1957
Pre 1954
1953
1967
1947
1948
1950
1955
1959
1957
1957
Pre 1954
Pre 1954
Pre 1954
1928
1940
1956
1958
1962
Pre 1954
1930
1944
1955
1964
1966
1968
Principal Raw Material
Sulfur
Sulfur
"
ti
Sulfur + Sludge
Sulfur
Sulfur
Zn or PB Smelter Gas
PB Smelter Gas
Sulfur
it
n
n
Zn Smelter Gas
Sulfur + Ore
Sulfur
n
ti
u
"
Sulfur + Sludge
ti it
it ti
Sulfur
"
"
11
"
n
Sulfur
Sulfur + Hydrogen Sulfide
Sulfur
"
Sulfur
"
"
"
"
Highest
Concentration
Product
Oleum
<99% Acid
"
"
Oleum
<99% Acid
<99% Acid
<99% Acid
"
Oleum
<99% Acid
"
"
<99% Acid
<99% Acid
^9% Acid
Oleum
"
"
"
"
^39% Acid
"
Oleum
n
M
M
II
tl
<99% Acid
n
Oleum
it
<99% Acid
"
"
"
n
-------
TABLE 5 - PAGE 5
State
Ohio
Oklahoma
Pennsylvania
Rhode Island
S. Carolina
Tennessee
Texas
Allied Chemical Corp.
Diamond Fertilizer Co.
DuPont
Inter. Min. & Chem. Corp.
Mobil Chem. Co.
Minn. Mining & Mfg. Co.
American Cyanamid Co.
Continental Oil Co. /Agrico Chem.
American Zinc Co.
DuPont
Ozark Mahoning Co.
National Zinc
New Jersey Zinc Co.
Witco Chem. Co. Inc.
Atlantic Richfield Co.
DuPont
Allied Chemical Corp.
U. S. Steel Corp.
Charles Pfizer Co. Inc.
St. Joseph Lead
Rohm and Haas Co.
Essex Chemical
W. R. Grace-& Co.
Cities Service Co. Inc.
Cities Service Co. Inc.
Volunteer Ordnance
Olin
Borden Chem. Co. /Smith Douglas
Phosphate Chem. Inc.
Potash Co. of America
Occidental Petroleum Corp.
American Plant Food Corp.
American Smelting & Refining Co.
DuPont
DuPont
Gulf Oil Corp.
Stauffer Chem. Co.
Olin
Shamrock Oil & Gas Corp.
Texaco Inc.
American Oil
Olin
Stauffer Chem. Co.
Stauffer Chem. Co.
Stauffer Chem. Co.
City
Cleveland
San dusky
Cleveland
Lockland
Cincinnati
Copley
Hamilton
Cairo
Columbus
North Bend
Tulsa
Bartlesville
Palmerton
Petrolia
Philadelphia
Cornwells Hts.
Newell
Neville Island
Easton
Josephtown
Philadelphia
E. Providence
Charleston
Copperhill
Isabella
Tyner
Pasadena
Texas City
Pasadena
Machovec
Plain view
Galena Park
Corpus Christi
La Porte
La Porte
Port Arthur
Baytown
Beaumont
Dumas
Port Arthur
Texas City
Port Arthur
Houston
Ft. Worth
Houston
Air Quality
Annual
Capacity
Control Region Short Tons
Cleveland
Cleveland
Cincinnati
Cincinnati
Cleveland
Cincinnati
Cincinnati
--.
Pittsburgh
Philadelphia
Philadelphia
Pittsburgh
Pittsburgh
Pittsburgh
Philadelphia
Providence
---
(1)
Chattanooga
Houston
Houston
Houston
Houston
Houston . .
Beaumont-Pt. Arthur
Houston .j.
Beaumont-Pt. Arthur
Beaumont-Pt. Arthur
Beaumont-Pt. Arthur'1)
Houston
Dallas-Ft. Worth
Houston
125,000
11,000
200,000
35,000
14,000
60,000
90, 000
43, 500
70,000
105,000
120,000
65,000
180,000
35,000
140,000
70,000
250,000
45,000
12,200
100,000
88.000
17,000
35,000
280,000
700,000
145,000
210,000
155,000
420, 000
15.000
105,000
140.000
70,000
85,000
265,000
105,000
275,000
180,000
32,000
92,400
173,200
70,000
620,000
120,000
700,000
Daily
Capacity
Short Tons
350
35
600
100
40
175
250
125
200
300
360
200
500
100
400
200
700
125
35
300
250
50
100
800
2,000
400
600
450
1,200
45
300
400
200
250
750
300
800
500
100
250
500
200
1.750
350
2.000
Year
17 W*^\
Built
Pre 1954
Pre 1954
Pre 1954
Pre 1954
1938
1942
1955
1960
1967
1955-59
1941
Pre 1954
Pre 1954
1933
1955-59
Pre 1954
Pre 1954
Pre 1954
1967
1968
1929-54
1929-49
1955-59
Pre 1954
Pre 1954
Pre 1954
1947
1953
1960-65
1960-65
1963
1965
Pre 1954
1955-59
1961
Pre 1954
1955
1957
1958
1965
1969
Pre 1954
Pre 1954
Pre 1954
1967
Principal Raw Material
Sulfur
"
"
"
11
"
"
"
Zn Smelter Gas
Sulfur
Hydrogen Sulfide
Zn Smelter Gas + Sulfur
Zn Smelter Gas
Sludge + Sulfur
Sludge + Hydrogen Sulfide
Unknown
Sulfur + Pyrite + Sludge
Sulfur + Hydrogen Sulfide
Ferrous Sulfate
Zn Smelter Gas
Sulfur
Sulfur
Sulfur
Pyrites
Pyrites
Sulfur
Sulfur
"
M
"
"
"
Zn Smelter Gas
Sludge + Sulfur
M n
Sludge + Hydrogen Sulfide
Sludge
Sludge + Hydrogen Sulfide
M n n
M n n
Sludge
M
11
11
11
Highest
Concentration
Product
<99% Acid
"
"
"
II
II
II
M
"
Oleum
<99% Acid
"
Oleum
"
"
<99% Acid
"
"
"
"
"
<99% Acid
<99% Acid
Oleum
<99% Acid
Oleum
<99% Acid
n
"
"
n
"
Oleum
1 '
M
<99% Acid
"
<99% Acid
"
n
M
Oleum
"
"
"
-------
TABLE 5 - PAGE 6
State
Utah
Washington
W. Virginia
Wisconsin
AZ Minerals Corp.
Kennecott Copper Corp.
Kennecott Copper Corp.
Kennecott Copper Corp.
American Cyanamid Co.
Borden Chem. Co. /Smith Douglas
Allied Chemical Corp.
Swift & Co.
Weaver Fertilizer Co. Inc.
Allied Chemical Corp.
DuPont
Hercules Powder
Georgia-Pacific Corp.
American Smelting & Refining Co.
Allied Chemical Corp.
Allied Chemical Corp.
DuPont
Olin
Western Nuclear Inc.
Western Nuclear Inc.
Totals - 214 Plants in 179 Eastablishments Producing -
Within AQCRs Totals - 93 Plants in 79 Eastablishments Producing -
City
Mexican Hat
Magna
Magna
Magna
Piney River
Norfolk
Front Royal
Buell
Norfolk
Hopewell
Richmond
Radford
Bellingham
Tacoma
Anacortes
Nitro
Barks dale
Baraboo
Riverton
Jeffrey City
Air Quality
Control Region
(1)
Salt Lake CityJ.J
Salt Lake City
Salt Lake City
...
Seattle -Tacoma
---
---
—
—
Annual
Capacity
Short Tons
28,000
260,000
140,000
175,000
30,000
70.000
140,000
47,000
30,000
140, 000
90,000
25,000
10,000
70,000
40,000
135,000
35,000
70,000
70,000
44,000
Daily
Capacity
Short Tons
100
750
400
500
85
200
400
135
100
400
250
70
30
200
125
400
100
200
200
125
Year
Built(2)(3)
1957
Pre 1954
1955-59
1967
1930
1937
1945
1947
1955-59
1966
Pre 1954
Pre 1954
1965
Pre 1954
1958
1948
Pre 1954
Pre 1954
1958
1962
Principal Raw Material
Sulfur
Cu Smelter Gas
rt IT it
" " "
Sulfur
"
"
"
11
ii
"
"
Sulfur
Smelter Gas
Sludge + Hydrogen Sulfide
+ Sulfur
Sulfur
Sulfur
"
Sulfur
ii
Highest
Concentration
Product
<99% Acid
ti
"
ii
<99% Acid
it
ii
"
"
"
Oleum
ii
<99% Acid
11
"
<99% Acid
Oleum
l:
<99% Acid
II
37, 722, 500 Short Tons/Yr.
13, 721, 400 Short Tons/Yr.
NOTES:
(1) AQCR not yet designated; plant located within SMSA.
(2) Where pre 1954 is given, exact date was not available.
(3) Where two dates are given, year built is within the span given, but exact date was not available.
-------
Illinois
Indiana
Kansas
Kentucky
Louisiana
Minnesota
Missouri
New Jersey
Ohio
Oklahoma
Pennsylvania
Tennessee
Texas
Utah
W. Virginia
Company
Alabama Ord. Works
Maumelle Ord. Works
Monsanto
Kankakee Ord. Works
Standard Oil Co. of Ind.
Wabash River Ord. Works
Sunflower Ord. Works
Kentucky Ord. Works
Rubicon Chemicals
Gopher Ord. Works
Weldon Spring Ord. Works
American Cyanamid
DuPont
DuPont
Plum Brook Ord. Works
Oklahoma Ord. Works
Pennsylvania Ord. Works
Keystone Ord. Works
Allied Chemical
Chickasaw Ord. Works
Holston Ord. Works
Volunteer Ord. Works
Texaco
Longhorn Ord. Works
Utah Oil Refining Co.
W. Virginia Ord. Works
American Cyanamid
Allied Chemical
Carbide & Carbon Chem. Co.
SULFURIC ACID PLANT CENSUS
TABLE 6
DRUM TYPE SULFURIC ACID
City
Sylacauga
Marche
El Dorado
Elwood
Wood River
Dana
Eudora
Paducah
Geismar
Rosemount
Weldon Spring
Bound Brook
Gibbstown
Gibbstown
Sandusky
Pryor
Williamsport
Geneva
Newell
Memphis
Kings port
Tyner
Port Arthur
Karnack
Salt Lake City
Pt. Pleasant
Willow Island
Moundsville
Institute
CONCENTRATORS
Air Quality
Control Region
.-.
Chicago
St. Louis
---
---
..-
---
Minneapolis -St. Paul
St. Louis
N.Y. -N. J. -Conn.
Philadelphia
Philadelphia
---
---
Pittsburgh
Memphis
(1)
Chattanooga
Beaumont-Port Arthur
Salt Lake City(1)
—
—
No. of Units
9
8
1
7
1
9
8
6
1
5
16
1
1
1
12
9
12
10
1
2
7
9
2
6
1
12
1
1
1
Year Built
1942
1941
1960
1942
1943
1942
1942
1942
1964
1942
1941
1941
1963
1966
1941
1941
1942
1942
1962
1942
1942
1942
1942
1942
1943
1942
1957
1964
1966
Total - 28 Establishments With 29 Plants and 160 Units
Within AQCRs Total - 11 Establishments With 12 Plants and 47 Units
NOTES:
(1) AQCR not yet designated; plant located within SMSA.
-------
>
3
<
-------
CONSULTING DIVISION
IV
EMISSION CONTROL SYSTEMS
A. SURVEY OF AVAILABLE SYSTEMS
Many systems for emission control for sulfuric acid plants and
other stationary sources have appeared in the literature, a few
of which are in commercial operation. Some have been extensively
tested in the laboratory, and in a pilot scale unit, but the majority
have been tested only in part, are patents untested on a continuous
basis or actual conditions, or represent undeveloped ideas.
Since SO9 and mist control in all cases represents an addition to
£i
the cost of producing acid, there has been no commercial incentive
to develop control processes or devices beyond the economic use of
raw materials and the requirements of a social nature imposed by
local governmental authorities. The majority of commercially
operating control systems have been in the area of mechanical
devices for acid mist control, since the presence of acid mist is
the easiest to detect and produces direct effects which tend to
evoke immediate complaints from owners of adjacent properties.
Mist control is also relatively inexpensive.
Control systems may be classified both by capabilities and by
type of system, but since many syslems which are basically the
same can be operated in such u manner that different results may
be achieved, we have classified the various systems by types.
IV - 1
-------
CONSULTING DIVISION
Processes have been divided into four groups, the first three of which
are most significant: -
1. x. x In plant modifications for SO control.
It
2.x. x Tail gas treatment systems for SO , SO and mist
control.
3. x. x Mechanical devices and systems control of mist in
tail gas.
4.x.x Systems applicable to chamber process acid plants.
These classifications have been further subdivided, as follows, using
the second digit to denote the following:-
1. 1.x Systems applicable to new plants only.
1. 2.x Systems applicable to new or existing plants.
1. 3.x Methods of conversion improvement.
2. 1.x Systems recovering sulfur values as. salable by-product.
2. 2.x Systems recovering sulfur values as additional acid
product.
2. 3.x Systems recovering sulfur values as disposable solid
waste product.
2. 4.x Systems recovering sulfur values partly as additional
acid product and partly as salable by-products.
3.1.x Mechanical devices.
3. 2.x Electro-mechanical devices.
3. 3. x Liquid absorbent syslems.
3.4.x Solid absorbent systems.
The third number, which identifies a process within a category, was
assigned arbitrarily as the processes were added to the survey, and
has no particular significance beyond identification.
IV - 2
-------
CONSULTING DIVISION
In general, processes in group 1 control SO emission, those in group
£
2 control SO , SO and acid mist emission, those in group 3 are for
£ 3
acid mist control only, and those in group 4 are for SO9 and NOX
&
control. Some group 2 processes may be used for SO? control only at
reduced operating cost. This will be discussed further in Part V.
The processes surveyed are listed below by identification number and
name. A process survey sheet on each of these processes appears in
the appendix.
I \mber Name
1. 1. 1 Dual Absorption (New Plant)
1. 2. 1 Add-On Dual Absorption using Converter Heat
1. 2. 2 Add-On Dual Absorption using Furnace Heat
1.2.3 Add-On Dual Absorption using Outside Heat Source
1.3.1 Ultraviolet Oxidation of SO
1. 3. 2 Ozone Injection to Catalyze Oxidation of Remaining SO9
C.I
1.3.3 Formation of Oxysulfuric Acid to Oxidize Remaining
S°2
1. 3. 4 SO-SO Conversion Improvement by Plant Adjustments
^ O
2.1.1 Na CO Absorption of SO to Produce Na2SO
2.1.2 MgO Absorption of SO9 to Produce MgSO
^ 4
2. 1. 3 Lime Absorption of SO to Produce Plaster of Paris
CA
2. 1. 4 Absorption with Ammonia-Oxidation of (NH ) SO« to
(NHJ0SO
24
2. 1. 5 SO2 to Convert Phosph.ite Rock to Saleable Fertilizer
2. 1. 6 Tl'iu Production of Peroxydisulfuric Acid to Absorb
and Oxidize SO9
2.1.7 Oxidation of SO2 in Air-SO2 Battery
2.1.8 Oxidation of SO in Selenium Oxide Slurry
IV - 3
-------
CONSULTING DIVISION
Number Name
2. 1. 9 SO Absorption with Na CO to Produce Na SO
^ £ o Z 4
2.2.1 Absorption and Recovery of SO with Na SO -NaHSO
<-< -I J • " L, O O
Solution
2.2.2 SO2 Absorption with Na2SO3 -NaHSO Solution; Recovery
of SO with ZnO. Sodium Sulfite-Bisulfite and Zinc Oxide.
£
2.2.3 Absorption of SO with MnO -Mg(OH>2 and Recovery by
Calcination (Grillo Process;
2.2.4 Absorption of SO2 with NaOH Solution; Recovery of
and NaOH with Reducing Agent
2. 2. 5 Absorption of SO with Na COg and Reduction to Sulfur
with CO+H Reform Gas
£
2.2.6 Magnesium Oxide Absorption of SO? with SO Recovery
2.2.7 Absorption and Recovery of SO with MgSO -Mg(HSO )
<~i i , • 2 3 O i
Solution
2. 2. 8 Potassium Sulfite-Bisulfite
2.2.9 SO Absorption with K PO to Form K S O and its
*~ £ .._-„ *J 4 <^ £ D
Conversion to Sulfur
2. 2. 10 Absorption of SO by K SO -KHSO ; Recovery of SO
with Aldehyde Bisulfite
2. 2. 11 Absorption with Ammonia-Recovery of SO from
Ammonia Bisulfite
2. 2. 12 Absorption of SO with Ammonium Sulfite and Bisulfite;
Recovery of SO9 with ZnO
^
2. 2. 13 Absorption of SO with Manganese Oxides with Recovery
of SO From MnSD
o ^t
2.2. 14 SO Absorption in and Recovery From Methylammonium
Sulfite-Bisulfite Solution
2.2. 15 SO9 Absorption in and R>-vovery From a Xylidine -Water
Mixture (Sulphidine Process)
2. 2. 16 Souium-Barium Salt System for Absorption of SO and
its Recovery as Sulfur
2.2. 17 Sodium-Barium Salt System for Absorption and
Recovery of SO
L*
IV - 4
-------
CONSULTING DIVISION
Number Name
2. 2. 18 Absorption of SO with Barium Hydroxide and its Recovery
from BaSO -BaSO
O ~E
of SO2 i
Liquid, and its Recovery From FeSO
2. 2. 19 Absorption of SO in Fe(SO) , FeSO4, and
.
2. 2. 20 Liquid Phase Oxidation of SO0 with Ozone
&
2.2.21 Activated Charcoal Slurry Absorption and Recovery of SO.,
2. 2. 22 Absorption and Oxidation of SO in Charcoal Beds
(Sulfacid Process)
2. 2. 23 Adsorption and Recovery of SO with Activated Char
(Reinluft Process)
2. 2. 24 Adsorption of SO with Dry Hydrated Lime with SO
Recovery by Calcination
2. 2. 25 Adsorption and Recovery of SO with Silica -Alumina
Alkali
2. 2. 26 Adsorption and Recovery of SO with Alkalized Alumina
Z
2. 2. 27 Adsorption of SO with Dry Magnesia and Recovery from
MgSO -MgSO
O T:
2.2.28 Adsorption with Basic Aluminum Sulfate Solution,
Regeneration with Heat to Release SO (Hardman Holden)
ILl
2.2.29 Resin Adsorption of SO
:t of SO Producing MgSO. From
*
2. 4. 3 I'ulham Simon-Carves; Production of Sulfur and
(NH ) SO From (NH ) SO -NH HSO Solution
rr ^ TC ~T ^ O * O
IV - 5
-------
CONSULTING DIVISION
Number Name
2. 4. 4 Absorption of and Recovery of SO_ Using (NH.LSO,,-
NH .HSOq and H_SC>
4 o ^4
2.4. 5 Ammonium Sulfite-Bisulfite Absorption with SO2 Recovery
and NH NO Production
4 O
2.4. 6 Sulfuric Acid-Lime 2 Stage Absorption to Recover SCX and
Produce Plaster of Paris
3. 1. 1 Dual Pad Mist Separator
3. 1. 2 Tubular Type Mist Separator
3. 1. 3 Panel Type Mist Separator
3. 2. 1 Electrostatic Precipitation
3. 3. 1 Mist Removal With Venturi Scrubber
3.4. 1 Absorption and Neutralization of Acid Mist and SO., With Lime
O
4. 1. 1 Absorption of NOX and SO2 with Solid MgSO- and MgO
4. 1. 2 Reduction of NOX and Absorption of SO2 with Sulfite-
Carbonate Solution
4. 1. 3 Absorption of SO and NOX with Sodium Hydroxide
In addition to these processes a study has been made of in plant process
modifications which is included with SO control systems under the
designation 1. 3. 4.
On the process survey sheets which are included in the appendix we have
used the terms "Licensor", "Expected Relative Cost" and "Reliability".
The term "Licensor" is used to identify an organization which may have
developed the process under consideration, and from whom it might be
licensed. It does not imply that any formal licensing terms are available.
Expected Relative Cost is a first impression estimate of the relative cost
of any process with respect to others which have similar applications and
capabilities. Reliability has to do with the effect of the process on the acid
plant's on-stream capability, not necessarily the on-stream capability of
the control system itself. For selected processes the on-stream factors
are more fully discussed in IV-C and D.
IV - 6
-------
CONSULTING DIVISION
B. FEASIBILITY AND APPLICABILITY CRITERIA
In order to measure the capabilities of various systems it is first
necessary to establish criteria by which the various systems will
be compared. For measurement of overall capability of a system
or process we have used the term "control effectiveness", which
may be defined as the total outlet concentration of sulfur expressed
as ppm of SO , regardless of the inlet concentration to the control
^
system. For mist control only the measurement is normally given
as mg/SCF.
Emission control systems were judged for feasibility by considering
a number of factors including stage of process development,
applicability to a significant number of existing acid plants,
potential for good control effectiveness for SO9, acid mist or both,
^
estimated on stream reliability, marketability of by-products (if
any), and overall estimated value compared to other systems with
similar chemistry or processing features. Those systems
selected for further analysis were evaluated at SO or overall
control effectiveness levels of 2, 000 ppm, 500 ppm, and 100 ppm
or less. 2,000 is chosen since it represents the approximate level
which can be achieved by most modern plants with careful operation
and minimum expenditure. The 500 ppm level respresents the
present aim of many of the pollution control regulations presently
under consideration in the United States. The 100 ppm level was
chosen since it represents a desirable level below which SO9 ceases
LJ
to be much of a problem, or which may be the long-range require-
ment in the future.
The concentration of SO9 in cleaned gas brings about concentra-
£A
tions of SO in the ambient air at ground level in proportion to
IV - 7
-------
CONSULTING DIVISION
the weight/unit of time being emitted from the stack. The contaminant
concentration at ground level is also governed by distance from source to
point of measurement, effective stack height, plus geographic and meteor-
ological factors. The effective stack height and distance from source should
be such that under the more unfavorable meteorological conditions the short
durationed "peak" SO0 concentrations should not exceed 1 ppm. A stack
Li
emission of 100 ppm from most acid plants will generally result in an
ambient air quality at ground level to satisfy this condition. For a specific
plant the emission would have to be calculated using stack height and other
local factors. A study of the effects of all the variables involved in the
relationship between ground level concentration and stack emission level
may be desirable.
Processes which control SO9 emission may or may not provide a
Li
measure of control for acid mist as well. It is desirable to reduce acid
mist emission to remove the visible plume from an acid plant stack.
All such plants will discharge some acid mist to the atmosphere, and
will combine with the moisture in the air to form additional acid
o
O
mist. Most devices presently used and which are incorporated on the
stacks of many existing plants will remove nearly 100% of all mist
particle of 3 microns or larger. The problem lies with that portion of
the mist which is droplets of less than 3 microns. By removing all
particles <3 microns the mist emission can generally be reduced to
2-3 mg. /SCF for plants producing up to 99% H9SO For oleum
^ 4
plants, however, removal of particles ^3 microns reduces mist
(1) Whittenberger, James L. M. D. and Frank, Robert N. M.D.
"Human Exposures to Sulfur Dioxide" - Archives of
Environmental Health - Vol. 7, No. 2, August 1963
IV -
-------
CONSULTING DIVISION
emission, but not nearly as effectively because the mist discharged from
an oleum plant stack contains a much greater percentage of finer droplets,
as discussed in Part III.
The relationship between the acid mist and SO0 concentrations in the
^
cleaned gas will be the same after dilution as at the stack, since mist
particles are small enough to behave as a gas, especially in the smaller
sizes. With the toxicity of acid mist at least 4 times as great as SO ,
emissions of acid mist should be in the order of 3. 0 mg/SCF (max. )
(25 ppm) to avoid a contamination problem. This range was calculated
using the same dispersion factors which are used to arrive at the SCX
limit on the preceding page, and assuming that mist will behave in
similar fashion. At these levels under some conditions there may still
be some visible plume.
Selection of Processes for Further Study
In examining many processes we find that technically many have almost
identical capabilities, requiring that further selection in many cases be
based on other considerations. Among these considerations are:-
Processes which have reached a stage of development most
closely approaching commercial operation receive
favorable consideration, assuming that no limiting
problems have been found.
(1) Ambient Air Quality Objectives - Classification System State
of New York Air Pollution Control Board, Dec. 11, 1964
IV - 9
-------
CONSULTING DIVISION
Processes which produce a by-product which has a probable
market in the U.S. are rated more feasible than processes
which produce a by product for which the present supply far
exceeds demand.
Processes which have application to many existing sulfuric
acid plants are considered more feasible than those with
limited applications.
Complex undeveloped processes are considered less feasible
than simple undeveloped processes.
Processes which have toxiclty problems, are obviously very
expensive, which rely upon assumed technology with un-
known capabilities are rated "not feasible", though at some
later date further work may make some "feasible".
In comparing two very similar processes, for which it can
be readily determined that one will have obvious cost
advantages over the other, the more expensive has been
rejected from further consideration in this study.
At least one "feasible" process has been selected from each sub-group of
processes as described on page IV-2. "Feasible" as used here of
necessity includes processes which are considered potentially feasible,
assuming that the process as generally described will perform as
expected. These generally apply to processes of the tail gas recovery
group, in which very few of the processes have ever been used on a
commercial scale. The only exception is chamber acid plants. This
is discussed in IV-E.
IV - 10
-------
CONSULTING DIVISION
C. SELECTED PROCESSES FOR SOp EMISSION CONTROL
Processes selected for more detailed review are grouped by control
effectiveness on Tables 7, 8 and 9. Table 7 lists processes by
identification number, which are for control of SO0 to 100 ppm and
^
below. The table also indicates if there are any limitations to the
type or size of plant to which they may be applied, and what the
concentration of SO in the inlet gas would be to have a 100 ppm
£t
exit level.
Tables 8 and 9 present similar data for processes which can
achieve 250 ppm and 500 ppm SO emission levels. The inter-
£*
mediate level of 250 (Table 8) was added, as this is the level which
can be reasonably achieved by most of the processes in Table 7
when applied to existing plants with the emission levels encountered
when plants are older, and are pushed to their maximum production
capability. These tables are based upon demonstrated absorption
capabilities of 95-96% for most systems. 100 ppm control effective-
ness might be achieved at increased SO9 inlet concentrations by
modification or additions to the absorption step.
The processes listed as having an optional capability for SO,, and
O
acid mist control are those which may or may not remove SO,, and
acid mist, depending upon the design of and pressure drop through
the scrubber. The cost of this option is covered in Part V.
Following Table 9 each of the selected processes is described,
and illustrated by process flow diagrams. These processes are
arranged in numerical order and are as follows:
IV - 11
-------
CONSULTING DIVISION
1.1.1 Dual Absorption
1. 2. 1 Add-On Dual Absorption Using Converter Heat
1.2.2 Add-On Dual Absorption Using Furnace Heat
1.2.3 Add-On Dual Absorption Using Outside Heat Source
1. 3.4 SO_-SOQ Conversion Improvement
£ o
2. 1. 1 Na CO Absorption of SO to Produce Na SO,,
£* O £ & O
2. 2. 6 Magnesium Oxide Absorption of SO2 with SO2 Recovery
2. 2. 8 Potassium Sulfite-Bisulfite
2.2. 14 SO Absorption in and Recovery from Methylammonium
Sumte-Bisulfite Solution
2. 2. 22 Absorption and Oxidation of SO in Charcoal Beds
(Sulfacid Process)
2. 2. 28 Absorption with Basic Aluminum Sulfate Solution,
Regeneration with Heat to Release SO (Hardman-Holden)
o
2.2.29 Resin Adsorption of SO
2.3.3 Lime Absorption of SO
2. 4. 5 Ammonium Sulfite-Bisulfite Absorption with SO
Recovery and NH .NO Production
4 o
2.4. 6 Sulfuric Acid-Lime 2 Stage Absorption to Recover SO
and Produce Plaster of Paris
It is recognized that several well developed processes have not been
included in the above list for further study because they produce a by-
product of which there is an overabundance. Notable in this group are
several tail gas treating processes which use ammonia based scrubbing
media, including 2. 1. 4, 2. 4. 3 and 2. 4. 4. One of these processes could
very well be very attractive to a fertilizer producer who would have a
natural market for a relatively small amount of (NH ) SO which
TT ^j T
could be used for blending in mixed fertilizers, for example. Process
2. 4. 4 would be quite similar to 2. 4. 5 which is reviewed, and which
produces an ammonium nitrate by-product.
IV - 12
-------
TABLE 7
FEASIBLE PROCESSES FOR
<100 PPM SO0 CONTROL EFFECTIVENESS
Process
2.
2.
2.
2.
2.
2.
2.
2.
1.
2.
2.
2.
2.
3.
4.
4.
1
6
8
14
29
3
5
6
£j
Limitations of Application SO0 Inlet Concentration, ppm
None
None
None
None
None
None
None
None
&
2, 500 or less *
2, 000 or less *
2, 000 or less *
2, 000 or less *
None
2, 500 or less *
2, 000 or less *
2, 500 or less *
Capable of SO and
Acid Mist Control
optional
optional
yes
yes
yes
yes
yes
yes
* Based upon an expected capability in the Removal Section of 95 to 96%.
-------
TABLE
FEASIBLE PROCESSES FOR
250 PPM SO2 CONTROL EFFECTIVENESS
Process
Limitations of Application
Limitation of SC>2
Inlet Concentration, ppm
Capable of Acid Mist
and SO0 Control
2. 1.
2. 2.
2.2.
2. 2.
2. 2.
2. 2.
2. 2.
2. 3.
2.4.
2.4.
1
6
8
14
22
28
29
3
5
6
None
None
None
None
None
None
None
None
None
None
6,
5,
5,
5,
2,
000 or
000 or
000 or
000 or
800 or
less *
less *
less *
less *
less **
None
None
6,
5,
6,
000 or
000 or
000 or
less *
less *
less *
— D
optional
optional
yes
yes
yes
yes
yes
yes
yes
yes
* Based upon an expected capability in the Removal Section of 95 to 96%.
** Based upon a reported capability of about 90% removal.
-------
TABLE 9
FEASIBLE PROCESSES FOR
500 PPM SO2 CONTROL EFFECTIVENESS
Process Limitations of Application
1.1.1 New S. Burning only
Existing S. Burning only
Existing S. Burning only
Existing Wet Gas only
1.
1.
1.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
1.
2.
2.
2.
2.
2.
2.
3.
4.
4.
1
2
3
1
6
8
14
22
28
29
3
5
6
Exist
Exist
Exist
None
None
None
None
None
None
None
None
None
None
Limitations of SO2
Inlet Concentration, ppm
Not Applicable
None
None
None
None
None
None
None
5, 500 or less *
None
None
None
None
None
Capable of Acid
Mist and SO Control
O
No
No
No
No
Optional
Optional
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
* Based on a reported capability of about 90% removal.
-------
CONSULTING DIVISION
Dual Absorption (1. 1. 1)
In the dual absorption sulfuric acid plant pollution is reduced by converting
a greater proportion of the sulfur dioxide in the feed to the converter to
sulfuric acid and, in principle, this must be considered the best solution
to the problem. It is, however, limited by theoretical considerations and
below 500 ppm of SO the catalyst loading and consequent power consump-
£
tion will increase appreciably.
In a dual absorption plant, Figure 13, the SO formed after partial
o
conversion in two or three stages is removed in a primary absorption
tower and the remainder of the gas, now with a very high O?/SO~ ratio
is returned to the converter. A heat exchanger - or a series of
exchangers reheats the gas from the absorber and cools the converted
gas going to it. Because the O /SO ratio in the partially absorbed gas
& £
is very high (at least 4:1 instead of 1. 5:1) the equilibrium conversion is
much higher and the second half of the converter with one or two stages
of catalyst will ensure that at least 99. 5% of the original SO0 content of
^j
the gas is fully oxidized. This high potential conversion is not very
much affected by the gas composition in the first part of the converter
with the result that it is possible to operate these stages at a higher
concentration of SO than normal. This permits a reduction in equip-
£i
ment sizes which goes some way to cover the cost of the additional
equipment required for the intermediate absorber stage.
The principle can be applied equally well to sulfur burning or wet gas
plants. Typically a sulfur burning plant will operate at the 10-12%
SO9 level for dual absorption instead of the usual 8%. A wet gas plant
£i
will also operate at a higher SO concentration than usual if this is
IV - 13
-------
".i
SULFUR
FURNACE
SULFUR •-
BOILER
FEED
WATER
DRYING
TOWER
I
-^-STEAM
CONVERTER
COOLER
BOILER
fPRIMARY
ABSORPTION
TOWER
HEAT
vEXC HANGER
[ECONOMIZER
.TAIL
GAS
SECONDARY
ABSORPTION
' TOWER
PRODUCT
ACID
COOLER
COOLER
USED ON JOB I
UST OF PARTS
CHEMICAL CONSTRUCTION CORPORATION
COMSULTtNC. DESIGNING AND CONTRACTING ENGINEERS
SCHEMATIC FLOW DIAGRAM
CONTROL METHOD I. I.I
DUAL ABSORPTION
ISSUED FOK CONSTRUCTION
AUTHORIZATION NO.
0064 C
FIG.I3
-------
CONSULTING DIVISION
available, as would normally be the case where H?S, pyrites or spent acid
was the raw material.
Because the wet gas dual absorption plant will contain two reheat cycles
instead of one, it is sensitive to low gas strength and the principle is
more difficult to apply to plants operating on a smelter gas where the
available SO0 is not under the control of the acid plant operator, than in
"
the more self-contained pyrites, spent acid or sulfur based plants. For
instance, if a plant is designed to operate on a copper converter gas
varying cyclically between 3% and 8% SO the converter stage, after the
^j
first absorption stage, will operate well at the 8% level, but when the
concentration falls to 3%, practically all the conversion will take place
in the primary stage, there will then be no heat generated in the
secondary catalyst and the temperature will fall below the reaction point.
When the gas strength recovers, it will be some time before the catalyst
in this last stage becomes active and there will be a period of poor
conversion. Although this problem could be mitigated by different
arrangement of heat exchangers, it would probably be found necessary
to use external heat in a converter preheater to maintain converter
temperatures under proper control. It is doubtful if the advantages
gained would be worth the trouble and expense entailed.
Except in these special cases, the dual absorption principle is a sound
method of reducing air pollution and has the advantage of not introduc-
ing any new or unfamiliar techniques to the acid plant operator. Plants
of this type have been operating in Germany and Holland for several
years using both sulfur and roaster gas as feed. New plants using
sulfur as feed are known to be under construction in the U.S. , U.K. ,
Japan and Australia, and some of these are now going into operation.
IV - 14
-------
CONSULTING DIVISION
A dual absorption plant requires very little more plant area than a
conventional single absorption plant. Although it includes an additional
absorber and heat exchangers, the size of much of the equipment is
somewhat smaller than the conventional plant. The dual absorption
process includes no different types of equipment or additional unspared
mechanical equipment, which means the on-stream factor should be
unaffected and the plant should require no additional operators.
Dual absorption will generally provide a control effectiveness better
than 500 ppm SCX. In itself it does not reduce the acid mist emission,
thus a dual absorption plant will require the same type of mist control
device as a conventional plant.
IV - 15
-------
CONSULTING DIVISION
Add-On Dual Absorption Using Converter Heat (1.2.1)
The gas from the stack of the existing plant is pressurized by a blower
and heated in a first heat exchanger by the gas leaving the secondary
converter (see Figure 14). It is then further heated in a new heat
exchanger installed in the base plant in parallel with the waste heat
boiler or heat exchanger used to cool the gas after the first conversion
stage. Dampers must be installed, if not already present,- to restrict
the flow through the existing boiler or exchanger to provide the heat
required for the new one. Where the original plant has a converter
boiler, the steam produced in it will be reduced. If it uses a heat
exchanger, more gas must be by-passed around the burner gas boiler
to make up for the heat taken by the new exchanger. In either case,
the steam produced in the old plant will be reduced by 10 to 20%.
If the original plant includes a converter exchanger, this can be used
for heating the new gas stream by making relatively simple piping
changes. Although this saves the cost of a new exchanger, it takes
more heat from the base plant than strictly necessary, resulting in a
lower steam production so that the lower initial cost is balanced by a
higher operating cost. In some cases, particularly where space is
limited, this may be preferred.
It is desirable to locate the new converter and exchanger close to the
original ones.
The converted gas from the secondary converter passes to the
secondary absorption tower where the SO., formed is absorbed in
O
98. 5% sulfuric acid. The absorber is furnished with the usual acid
IV - 16
-------
l
'
ECONOMIZER
CONVERTER
ABSORPTION
TOWER
BOILER
OR
EXCHANGER
EXISTING PLANT'
PUMP TANK
& PUMP
MAKE-UP
WATER
ACID
PRODUCTS
TAIL
GAS
COOLER
SECONDARY
ABSORPTION
TOWER
BOOSTER
BLOWER
PRIMARY
HEAT
EXCHANGER
SECONDARY
HEAT
.EXCHANGER
SECONDARY
CONVERTER
"ADD ON DUAL ABSORPTION
SYSTEM - CONVERTER HEAT
USED ON JOB |
1 '
CHEMICAL CONSTRUCTION CORPORATION
CONSULTING. DESIGNING AND CONTRACTING ENGINEERS
NEW TOW. M. T.. U.B.A.
SCHEMATIC FLOW DIAGRAM
CONTROL METHOD 1.2.1
ISSUED FOR CONSTRUCTION
ALTTHOfltZATION NO.
0064 C
DHAWIMC NO.
FIG.14
-------
CONSULTING DIVISION
circulation and cooling system which should be connected to the circula-
tion system of the base plant so that the acid concentration can be
controlled and the product removed. Tail gas is exhausted to the
atmosphere from the absorption tower, and in most cases the process
can be designed so that the SO emission will not exceed 500 ppm SO0.
& &
The process has advantages in addition to reducing SO9 emissions.
u
SO9 being wasted will be converted to product acid. It may be possible
£»
to increase the SO9 concentration in the base plant and so increase
^
production. The increase in concentration will cause decreased
conversion in the base plant which is then recovered in the secondary
system. This will permit the additional operating cost to be distribu-
ted over a larger production tonnage, reducing somewhat the increased
cost per ton without exceeding a 500 ppm emission.
The process is not affected by the present plant emission level, but,
as shown in Part V, the control cost is lower when the process is
applied to the less efficient plant.
The space required for the additional equipment for this process is
about 2, 500 sq. ft. for a 250 T/D conventional plant. The space should
be located near to the existing converter and absorber. The acid
coolers should be added adjacent to the existing ones to avoid additional
water piping. This space may be difficult to find in some plants which
have been surrounded by a chemical complex. Additionally, some
equipment will probably require field erection which means access
must be available for heavy construction equipment. In order to tie-
in the new equipment, a longer than normal acid plant shut down will
probably be necessary.
IV - 17
-------
CONSULTING DIVISION
As with a new dual absorption plant, process 1. 2. 1 will provide a control
effectiveness of <500 ppm SO , and will not affect acid mist emission.
&
Since this process will reduce acid plant steam production, a complex
which is "tight" on steam may have to provide an alternate steam or
heat source.
Process 1. 2. 1 should have a high on stream factor, since it adds only
one centrifugal type blower to the mechanical equipment, (acid pumps
are normally spared) but the overall onstream factor may be slightly
reduced, perhaps 1%. No additional operators should be required.
Add on dual absorption (process 1. 2. 1 and 1. 2. 2) are being offered
commercially, although none have been built as yet. They represent
no real departure from current sulfuric acid design or technology.
IV - 18
-------
CONSULTING DIVISION
Add-On Dual Absorption Using Furnace Heat (1.2.2)
The stack gas from the base plant is pressurized by a blower and partially
heated by the gas leaving the secondary converter. (Figure 15) The
additional heat to bring it up to reaction temperature is then obtained by
mixing - with the stack gas - hot burner gas from the sulfur furnace of
the base plant. As the gas will be at a temperature of 1, 600 F to 1, 900 F,
only a small quantity will be required to heat the tail gas from 700 F to
800 F. Because this gas contains 10 to 12% SO which bypasses the first
£
converter system, a two stage converter is required to give conversion
equivalent to process 1. 2. 1. The control of the temperature of the
second stage is obtained by mixing the partially converted gas with a
proportion of the 700 F tail gas from the first heat exchanger.
The converted gas from the secondary converter passes to the
secondary absorption tower where the SOQ formed is absorbed in 98. 5%
O
sulfuric acid. The absorber is equipped with the usual acid circulation
and cooler system and this is connected to the circulation system of the
base plant so that the acid cone entration can be controlled and the
product removed. Tail gas is exhausted to the atmosphere from the
absorption tower outlet and, in most cases, this gas contains less than
500 ppm of SO .
£
In addition to the advantages cited for process 1. 2. 1, this system can
produce additional acid from the additional sulfur burned to provide
heat for the second converter. The quantity is limited only by the
capacity of the main blower and the sulfur furnace. Additional
modifications to the heat exchange system could increase plant
capacity by as much as 35%.
IV - 19
-------
M
£_!
5
5£
5
-
3
ii
_sj
is
s
•
Is
s
.EXISTING
CONVERTER
SYSTEM
AIR •
SULFUR
ABSORPTION
TOWER
T
BOILER
SULFUR FURNACE
EXISTING PLANT'
PUMP TANK
& PUMP
BOOSTER
BLOWER
HEAT
EXCHANGER
-ADD ON DUAL ABSORPTION
SYSTEM - FURNACE HEAT
ACID
'PRODUCTS
MAKE-UP
WATER
SECONDARY
COOLER
N
TOWER
SECONDARY
CONVERTER
USED ON JOB
loiMNI
| rod j
LIST OF PARTS
CHEMICAL CONSTRUCTION CORPORATION
CONSULTING. DESIGNING AND CONTRACTING ENGINEERS
HEW TOW. M. T.. U.I A.
SCHEMATIC FLOW DIAGRAM
CONTROL METHOD 1.2.2
ISSUED FOR CONSTRUCTION
AUTHORIZATION NO.
0064 C
FIG.I5
-------
CONSULTING DIVISION
The drawbacks of process 1.2.2 are the same as those cited for process
1. 2. 1. The additional space requirements, the on stream reliability
and operator requirements are also the same as for process 1. 2. 1.
IV - 20
-------
CONSULTING DIVISION
Add-On Dual Absorption Using Outside Heat Source (1.2.3)
This process is essentially the same as process 1. 2. 1 (see Figure 16)
except that the heat for raising the temperature of the gas leaving the
primary absorber to the proper temperature for introduction into the
secondary converter is provided from an outside heat source by burning
fuel oil or natural gas. This is necessary in a wet gas plant in which
there is no excess heat available, such as a plant operating on smelter
gas. With other types of wet gas plants, though heat gas would be
available, as from a sludge furnace, the SO would be wet and not
^
suitable for introduction into the converter as in process 1. 2. 2.
This process can achieve the same result as 1. 2. 1 and 1. 2. 2 for wet
gas plants, but at an obviously greater expense because of fuel
requirements. It is possible that a special situation might exist where
an outside waste heat source adjacent to a wet gas plant could be
utilized to permit an installation like 1. 2. 1, with no cost heat, but
this is remote.
The on stream factor will be slightly lower than 1. 2. 1 and 1. 2. 1 due
to the furnace and fuel supply required. Additional operator attention
probably would not be required since "wet gas" plants generally have
more operators than a sulfur burner, being more complex.
Space requirements for 1. 2. 3 would be about 3, 500 sq. ft. for a 250 T/D
plant, since wet gas plants, due to generally lower gas strengths, have
larger equipment than sulfur burners. This space may be difficult to
find around a sludge or H9S burning plant, or a smelter gas plant.
£i
IV - 21
-------
56
s
AIR
PREHEATER
CONVERTER
ABSORPTION
TOWER
COMBUSTION
CHAMBER
TAIL GAS
BLOWER
ABSORPTION
TOWER
PRODUCT
ACID
EXISTING
PLANT
USED ON JOB I
ADD ON DUAL
•*• ABSORPTION SYSTEM
USING EXTERNAL
HEAT SOURCE
USTOT PMT»
CHEMICAL CONSTRUCTION CORPORATION
SCHEMATIC FLOW DIAGRAM
CONTROL METHOD 1.2.3
MnMOKUTKM K).
0064C
FIG.16
-------
CONSULTING DIVISION
This process will have all the problems of access to construction space,
shutdown for installation, and limitations as described for process 1. 2. 1.
It will, similarly, provide no additional acid mist control. There is no
possibility of greatly increased production with smelter gas plants since
the sulfur supply is not controlled by the acid plant operator.
IV - 22
-------
CONSULTING DIVISION
SOp'SOp Conversion Improvement (1.3.4)
Probably the easiest method to reduce SO2 emission levels from existing
plants is to improve SO0 conversion by modifying the parameters which
£i
control the SO_ oxidation reaction. These parameters are:-
£
(1) Catalyst quantity and activity
(2) Reaction gas composition
(3) Reaction gas temperature
(4) Residence time
(5) Removal of reaction products
The discussion that follows will deal exclusively with the conversion
improvement of existing single absorption H0SO plants by means of
£ ~t
items 1 through 4 listed above. Item 5 deals with dual absorption and
has already been discussed.
Possible in-plant modifications are:-
(1) Addition of extra catalyst to one or more beds of existing
catalyst in the converter, or complete catalyst replacement.
(2) Lower the SO9/O9 ratio by the addition of oxygen or air to the
£ u
reaction gas either prior to the first catalytic stage or later
at any intermediate stage.
(3) Lower the feed temperature of the reaction gas. In most
cases this will necessitate replacing the existing catalyst
with low temperature catalyst.
(4) Increase the residence time either by installing a new
converter in parallel with the existing one or by reducing
reaction gas throughput, i. e. , reducing plant capacity. In
IV - 23
-------
CONSULTING DIVISION
this study the installation of a new converter will be ignored
because of the special nature of such a venture, subject to
space limitations, revamp of duct work, etc. On the other
hand, most sulfuric plants are operated at a higher capacity
than design at the expense of higher SO9 emissions.
^
The modification of a specific plant may involve the adoption of any one
improvement method or a combination of all four. Due to the wide
divergence of design parameters and operation of existing converters,
when discussing possible modifications an improvement limitation
approach has been taken, rather than proposing a specific modification
scheme for a class of converters. In the future, when implementing
these modifications, each case must be studied on its own merits.
The practical aspects of the theoretical limitations discussed in
Part III-A are as follows:
Catalyst Addition
Usually only 3-6 inches of additional bed height is available
per stage. Air quench type converters are expected to
have more room for catalyst addition.
Air Addition
Fan capacity is the most important limiting factor. Existing
air dryers and associated equipment should be able to handle
extra air within limits, heat exchangers likewise. In
general, existing equipment should be able to handle a 10-
15% increase over design air rates. Table 10 lists relative
air requirements for feed gas concentrations of 4% to 12%
IV - 24
-------
CONSULTING DIVISION
TABLE 10
RELATIVE AIR REQUIREMENTS
BASIS 8% SO,. FEED AIR = 1.0
Air Rate Factor
4 2.000
5 1.600
6 1.334
7 1. 143
8 1.000
9 0.889
10 0.800
11 0.727
12 0.666
-------
&*i0TnuM6
CONSULTING DIVISION
SO_. The tight water balance of an oleum plant may require the
^j
additional air to be predried in equipment other than the drying
tower.
Feed Temperature Reduction
As discussed earlier this is useful only at the final conversion
stage, the existing catalyst has to be replaced by low
temperature catalyst and intercoolers preceding the stage may
be easily altered for extra heat exchange.
In some cases a higher capacity cooling air fan may be required.
Reduced Production
As discussed in Part III-A, conversion may be improved by burning
less sulfur, with or without reduction in air flow. This is a costly,
but sometimes necessary way to temporarily reduce emission
during adverse atmospheric conditions. Most plants can probably
operate at 50 to 60% of capacity with improved conversion, and still
maintain proper reaction temperature in the converter. A minimum
temperature is especially important in the last stage, where if the
reaction is insufficient to offset heat losses, higher SO emission
£
will result.
It can be seen from Figure 3 that it is all but impossible to achieve any-
thing near 500 ppm emission level with any or all of the modifications
discussed above. Nevertheless, these are completely feasible
approaches to achieve some reduction in SO emission levels. These
di
modifications require minimum capital cost, little or no additional
space and no additional plant personnel. The improvement may be
marginal, but where a plant is operating just outside acceptable
standards the methods discussed here should be carefully considered.
IV - 25
-------
CONSULTING DIVISION
Sodium Carbonate Absorption of SO? to Produce Sodium Sulfite (2.1.1)
The objective of this process is to produce a salable sodium sulfite from
sodium carbonate and the SO? in the acid plant tail gas, reducing the total
emission level of sulfur dioxide from 2, 000 ppm to as low as 100 ppm.
This process is not in commercial operation, although a considerable
amount of development work has been done. Since the process requires
low pressure steam which is often available in excess from H0SO plants,
^ 4
this process is considered potentially feasible. Na?SO3 should find a
market, possibly in the paper industry.
Sulfur dioxide, SO~ and acid mist are removed in a single-stage venturi
o
type scrubber (Figure 17). The scrubbing liquid is primarily a solution
of sodiums ulfite with smaller amounts of sodium sulfate and carbonate.
SO2 is absorbed into the scrubbing liquid, it then reacts with the sodium
carbonate to form sodium sulfite. Some of the sulfite is oxidized to
sulfate. The acid mist and SO- are removed from the gas stream by
o
entrainment in the absorbing solution in the throat of the scrubber. Any
SOo is converted to acid mist. Since the single scrubber would be
primarily designed for SO absorption, removal efficiency for acid mist
L*
may not reach the optimum. The entrained acid and trioxide react with
the alkali to form sodium sulfate. The reactions are as follows:
S02
SO3
CO,,
Sodium carbonate is brought into the system dissolved in the required make-
up water. An oxidation inhibitor is added in small amounts to minimize
oxidation of the sulfite to sulfate.
IV - 26
-------
TAIL GAS
GRAVITY
FEED
SODIUM SULFITE
CRYSTALS
WEIGHTOMETER
AND FEEDER
CHCMXAL COMSTKUCT1ON CCWPOfUTON
TAIL GAS SCRUBBING PROCESS 2.1.1
NizCOj ABSORPTION OFS02
TO PRODUCE NajSO,
FIG. 17 P,
-------
CONSULTING DIVISION
A bleed stream is drawn from the scrubber stream to process the sodium
sulfite. The solution is first cooled to abouc 35 F in a steam-jet vacuum
crystallizer. Hydrated sulfite and sulfate are precipitated and a slurry
of this material is centrifuged. Supernatent liquids are returned to the
scrubber. The hydrated crystals are then heated (to 110 F) in a secon<
crystallizer forming a slurry of anhydrous salts. These salts are
o
centrifuged, and then dried at 250+ F in a rotary dryer fired with natur
gas. The dried salt is then ground and sent to storage.
Processing problems may be encountered in preventing oxidation of
sulfite to sulfate in the scrubber and other parts of the system to
maintain a minimum percentage of sulfite in the product. A
suitable oxidation inhibitor would have to be selected. The ease with
which sodium sulfite is precipitated in the low and high temperature
crystallizers must also be determined.
The complexity of the process will require the attention of a full time
operator plus a second on a part time basis for handling of the by-
product.
Space requirements for process 2. 1. 1 for a 250 T/D sulfur burning
plant whould be approximately 2, 500 sq. ft. , none of which need be
inside the acid plant battery limits. The scrubber would need to be
located adjacent to the acid plant, but the remainder of the system could
be some distance away, with the bleed stream being piped to it and makeup
Na CO returned. Only two small lines are required.
^ O
Since the recovery process is not integral with the acid plant it in no
way will affect the on-stream factor of the acid unit. Should it be
IV - 27
-------
CONSULTING DIVISION
shut down the scrubber would operate until the holding tank was filled.
If the 2. 1. 1 process were still not operating, SO would have to be
b
temporarily vented to atmosphere. Process 2. 1. 1, having a relatively
large number of mechanical items probably would have a lower on-
stream factor than the associated H9SO. unit.
The number of potential users is rather limited by the by-product
Na SO The largest potential market is in kraft pulp mills which
^ O
presently buy Na0SO.. The sulfite, if available, would provide the
^ ~I
same Na and S values in a smaller tonnage for mixing with black liquor,
the ultimate need in the kraft process being for Na9S. Since the location
of kraft mills is limited geographically, the acid plants with potai tial
applications for process 2. 1. 1 would be those in reasonable proximity
to kraft pulp mills. Many kraft mills, of course, are located in the
southeastern states as are many acid plants.
An acid plant pushed to maximum capacity with process 2. 1. 1 as a control
system will produce additional sodium sulfite, as well as additional H9SO .
u ~t
This may be a disadvantage, depending upon the Na SO., market. A 250
& O
T/D H0SO plant with a 4, 000 ppm emission level would produce approx-
^ 4
imately 15. 5 T/D of dry Na9SO» including some Na SO and Na CO which
£ o £ Q. £ »j
are tolerable for the suggested end use.
As with rrany other ta 1 gas treatment processes, the control effective-
ness of the process is affected by the inlet SO9 concentration. With a
£
95% removal, the control level can be 250 ppm with an inlet concentra-
tion of 5, 000 ppm, and 100 with an inlet SO concentration of 2, 000.
<£
A greater removal than 95% is possible by changing the composition of
the scrubbing liquid or adding absorption stages.
IV - 28
-------
CONSULTING DIVISION
Magnesium Oxide Absorption of SO9, With SO Recovery (2.2.6)
^ £t
The objective of this process, illustrated by Figure 18, is to absorb SCX
in a magnesium oxide-sulfite water slurry and then calcine the magnesium
sulfite to recover the SO0 and the magnesium oxide.
Ci
The process can reduce the sulfur emission level, for example, from
2, 000 ppm to about 100 ppm. Although this system is not yet in
commercial operation, it has operated successfully in pilot scale on a
sulfuric acid plant, and commercial scale units have been proposed.
The SOp, SO,, and acid mist are removed from the tail gas in a single-
stage venturi type scrubber. SO,., is absorbed into the slurry, reacting
with the magnesium oxide to form magnesium sulfite. Acid mist and SO
O
are removed by entrainment in the scrubber. In similarity to process
2.1.1 acid mist removal efficiency would have to be ascertained. The
SOo and H^SO. combines with the oxide to form magnesium sulfate.
Some magnesium sulfite is oxidized to sulfate by the oxygen in the tail
gas. The chemical reactions are as follows:
MgO + SO + 6H O _ > MgSO 6H O
£* £t O £
MgO + SO3 + 7H2O - > MgSO4.
MgO + H2S04 - . MgS04
MgSO + 1/2 O + 7HO -------- ;• M
A bleed stream of the slurry is processed to recover the SO9 and
£
regenerate the magnesium oxide absorbant. The slurry is first
centrifuged to remove most of the free water. The wetted solids are
then dried in an oil-fired rotary dryer to remove the free water as
well as the waters of hydration. Following the drying the salts are
IV - 29
-------
l\
I
TAIL GAS
ACID MIST
MAGNESIUM
SALT SLURRY
FAN
MAKE-UP
CLEANED
GAS
I FAN
VENTURI ABSORBER
AND ACID MIST SCRUBBER
CENTRIFUGE
PUMP
L_
MOTHER
LIQUOR
TANK
, FAN
^C
FUELOILPUMP
PUMP
CYCLONE
4) COMPRESSOR
J
CALCINER
CHEMICAL CONSTRUCTION CORPORATION
CONSULTING. DESKMMG AND COtrntACTHK EMOHEEMS
KTW mm, H. T.. 0,1*.
TAIL GAS SCRUBBING PROCESS 2.26
MAGNESIUM OXIDE
ABSORPTION OF S02WITH S02RECOVERY
ISSUED mo COMSTRUCT1ON
AUTHOmTATKJM NO.
0064 C
DRAW1MC BO.
FIG. 18
-------
CONSULTING DIVISION
calcined, decomposing to SO9 and magnesium oxide. Coke is added to
reduce magnesium sulfate to sulfite:-
MgSOQ \ MgO + S09
O <£
2MgSO. + C > 2MgSO_ + C09
4 O £
The calciner can be either oil or gas-fired and the off-gases containing the
SO9 and some MgO dust are passed through a c;yc lone to remove most of
the dust, and then through a scrubber for a final cleaning. The scrubbing
liquid is magnesium bisulfite. The gases are then indirectly cooled to
condense most of the moisture. Following this they are compressed to
atmospheric pressure before being returned to the acid plant.
The calcined material, MgO, is sent to the slurry tank where it is
slurried with the required make-up water for return to the scrubber
system. Magnesium oxide make-up is also added to the slurry tank.
The magnesium bisulfite bleed stream from the calciner dust scrubber
is sent to the SO9 absorber.
The control effectiveness of this process is affected by inlet SO9
concentration. Tests have demonstrated that 95% of the SO can be
removed in the scrubber. At constant SO concentration the cost
of controlling to 200 ppm is insignificantly higher than controlling
to 500 ppm. If SO? concentration increases the exit SO9 concentra-
tion can be maintained by adding more alkali to the absorbing slurry.
The physical space requirements for process 2. 2. 6 for application to
a 250 T/D H9SO plant is about 2, 000 sq. ft. The entire unit should
& TT
be located adjacent to the acid plant, but not necessarily within the
IV - 30
-------
CONSULTING DIVISION
battery limit. Being adjacent to it will permit a short duct for return of
SO to the drying tower.
Mechanical equipment will tend to reduce the on stream factor of the
process below that of the acid plant, and will also require the attention
of a full time operator. Since the system is independent of the acid
plant it will not affect operation of the acid plant, but will mean SO
is vented to atmosphere when the recovery process is not operating.
Since the product of this system is SO?, operation of the acid plant
above design levels when using process 2. 2. 6 can permit a substantial
increase in acid production while keeping SO emissions below 500
ppm.
IV - 31
-------
CONSULTING DIVISION
Potassium Sulfite-Bisulfite (2.2.8)
This process is basically of the type developed by Wellman-Lord for
absorption of SO with a potassium sulfite-bisulfite solution, which is
LA
subsequently heated to liberate SO0. The process has been piloted,
LA
and a commercial scale unit is being constructed. A version of this
type of process is illustrated by Figure 19.
The tail gases are first scrubbed in a high pressure drop venturi with
a sulfuric acid solution to remove acid mist and SO_. Depending upon
o
inlet concentrations, very high removal efficiencies can be obtained
(in the order of 99%). Following this, the SO? is absorbed in two
stages with potassium sulfite-bisulfite solutions. A solution stronger
in bisulfite in the first stage (higher permissible SO vapor pressure)
o
is bled to the regeneration part of the system. An oxidation inhibitor
is added to minimize oxidation of sulfite to sulfate. The absorption
chemistry is as follows:
+ H20 - , 2KHS03
The sulfite-bisulfite bleed stream is first cooled to about 40 F to
precipitate potassium pyrosulfite:
2KHSO., - > K,S,0, + H00
o £ i 0 2>
This is done to concentrate the SO9 recoverable material to a maximum.
L*
The pryosulfite crystals are separated by centrifuging. Water is then
added to the crystals to form a bisulfite-pyrosulfite slurry which is fed
into the steam stripper.
IV - 32
-------
TAIL GAS
-VENTURI ABSORBERS
SOj
JL=
WATER
STEAM—»r
V
VACUUM CRYSTALLIZER
WITH STEAM JET VACUUM
COOLING
KA05
KHS03SLURRY
TAIL GAS SCRUBBING PROCESS 2.3.8
POTASSIUM SULFITE - BISULFITE
RECYCLE & RECOVERY OF S02
0064 C FIG. 19 P
-------
CONSULTING DIVISION
In the steam stripper, the bisulfite-pyrosulfite slurry is indirectly
heated to about 250 F with steam from the acid plant. The pyro-
sulfite crystals dissolve to form bisulfite and the latter decomposes
to sulfite and SO :
&
2KHSO0 > K SO0 + HO
6 ^ o 2
The overhead gas is a saturated steam-SO0 mixture which is passed
through a water-cooled condenser where the mixture is indirectly
cooled to about 110°F. The condensate, a saturated SO0 solution, is
£A
returned to the stripper, and the cooled, highly concentrated SO9 gas
^
is cycled to the acid plant.
The decomposed solution containing potassium sulfite with a smaller
amount of bisulfite is mixed with the alkali and water make-up before
it is cycled to the second absorption stage. The alkali reacts as
follows:
K,CO + 2KHSO * 2K0SO_ + CO9 + H0O
£i O O £i o £i Ct
Some areas of this process which may require further development
involve the absorption efficiencies of SO0 in both stages as related to
Lt
bisulfite-sulfite concentrations. Also, the temperature-time-
recycle-percent precipitation relationships of the crystallization of
potassium pyrosulfite need to be fully determined. The steam
consumption in the stripping of the bisulfite-pyrosulfite slurry and
the percent bisulfite decomposition need verification, all by continu-
ous operation on a commercial scale. Since complete information
has not been released on the details of the process, some of this
information may already be developed.
IV - 33
-------
CONSULTING DIVISION
It would be desirable to find an oxidation inhibitor to minimize oxidation
of sulfite to sulfate if this is not presently done. The sulfate is not
readily regenerated to sulfite for recirculation, and sulfate buildup
would gradually render the process ineffective.
The equipment required for the version of this process illustrated in
Figure 19 is mainly vessels handling gases and liquids with a minimum
of mechanical equipment which should give an on stream factor
similar to that which is expected of a contact acid plant. Since it
operates independently of the acid plant, process 2. 2. 8, when not
operating, would vent acid plant tail gas to atmosphere as at present.
Multiple scrubbers, crystallizer, centrifuge and make-up tanks will
require a full time operator for the process.
The small amount of weak acid from the mist scrubbing stage can be
cycled to the acid plant.
About 2, 000 square feet would be required for the illustrated system
adjacent to a 250 T/D acid plant for the same reasons as described
for process 2. 2. 6.
IV - 34
-------
CONSULTING DIVISION
SO? Absorption in and Recovery from Methylammonium Sulfite -
Bisulfite Solution (2.2.14)
This process to control SO0, SO,, and acid mist at a control effectiveness
LA *J
as low as 100 ppm and recover SO for recycle to the acid plant has not
been operated commercially, but is included for its apparent potential as
a feasible process and is illustrated by Figure 20.
SO9 is absorbed in two counter-current absorption towers with methyl-
ammonium sulfite-bisulfite solutions. The bleed streams are then
heated in a steam stripper, releasing SO for recycle to the acid plant,
with the bisulfite being converted to sulfite. The absorbing solutions
are prepared from liquid methylamine and sulfur dioxide.
SO0 is absorbed with the following reaction taking place:-
The concentrations of bisulfite and sulfite were carefully calculated to
keep SO0 and methylamine vapor pressures sufficiently low to have the
required absorption of SO with minimal evolution of methylamine
£i
vapor. (There is a vapor pressure of methylamine even though it
exists in the combined state with SO«.) At the absorption temperatures
the vapor pressure of methylamine is quite low.
Bleed streams from the two absorption towers are fed into a steam
stripper where the incoming liquid is preheated in two stages; first by
the existing liquid and then by 50 pound steam from the acid plant. The
liquid in the tower Is heated indirectly by 50 pound steam. The rich
liquid is stripped by the rising vapor mixture and methylamine vapor
IV - 35
-------
METHYLAMMONIUM
SULPHITE - BISULFITE
PREPARATION TANK
( INITIAL OPERATION ONLY)
TAIL GAS SCRUBBING PROCESS 3.^.14
SOzABSQRPTION IN AND RECOVERY FROM
METHYLAMMONIUM SULFITE- BISULFIDE
SOLUTION
0064 C
FIG. 20
-------
CONSULTING DIVISION
is condensed by a reflux stream from a partial condenser. The exiting
SO0 gases are cooled indirectly with the removal of most of the water.
M
The stripper bottoms containing methylammonium sulfite and water are
recycled to the absorption towers. Make-up to the system is in the form
of methylamine sulfite and is prepared in the same fashion as the
absorbing solutions.
Since this process has not been developed it has several potential
problems, which must be resolved. There may be difficulty in prepar-
ing large quantities of methylammonium sulfite-bisulfite for initial
operations because of the volatility and flammability of methylamine.
The extent of oxidation of the solution to methylamine sulfate in the
absorption and stripping stages is unknown. Johnstone specified
hydroquinone as an oxidation inhibitor, but this should be confirmed
with pilot tests.
The control effectiveness can be varied by changing the size of the
absorption towers. Mist is removed as with process 2.2.8.
This potentially feasible process should be relatively simple to
operate with the part time attention of an operator. Being a gas-
liquid system with no complex mechanical equipment it should have a
high on stream factor, as good or better than a contact acid plant.
Like other tail gas treating systems, 2. 2. 14 operates independently
of the H SO plant to which it is applied.
& 4
A unit for tail gas emission control on a 250 T/D sulfurLc acid plant
would require about 2, 000 square feet adjacent to the acid plant.
IV - 36
-------
CONSULTING DIVISION
Absorption and Oxidation of SO in Charcoal Beds (Sulfacid Process) (2.2.22)
This process, as illustrated by Figure 21, has been modified to satisfy acid
plant conditions over a range of SO9 concentrations in tail gas from 3, 000 to
833 ppm, equivalent to acid plant efficiencies from 96% to 99%.
This process, which is in commercial operation in Europe, catalytically
oxidizes SO_ to dilute sulfuric acid and then concentrates the acid to the
point at which it may be recycled to the acid plant without upsetting the
plant water balance. Concentration is achieved in a venturi type scrubber
by saturating the tail gas. Supplementary heat is added upstream of the
scrubber to achieve more evaporation at lower acid plant efficiencies.
The sulfacid process in its present stage of development employs activated
carbon to catalytically oxidize 95% (in this example) of the SO to form a
f.4
10% H SO . Gas velocity through the catalyst bed is quite low, in the
^ 4
order of 0. 33 feet per second.
The degree of concentration required for acid produced by the sulfacid
process depends upon several factors, including existing acid plant
conversion efficiency, the grades of product acid being produced and the
humidity of the air entering the plant via the drying tower.
It can be seen from Table 11 that at a plant efficiency of 99% or better
(with humidity and product grade fixed) all of the 10% acid can be
assimilated by the acid plant without evaporation supplementary heat
being required. Between 98 and 99% the 10% acid must be concentrated
in the scrubber before recycle to the acid plant. Below the 98% level
supplementary heat is required and this may be provided by direct firing
in the duct upstream of the venturi, enabling additional water to be
IV - 37
-------
\3
<
TAIL GAS
METHANE
' : AIR
WATER
k
50lb. STEAM
COOLING
WATER
i
TRATOR
—f
1
\ /
x1/
TWO STAGE
SAT U RAT OR
QUENCHER
/ — } \ \ \
1 ' frjL^ — : — <. — i — i — ^ -. — : A
V I
1 CATALYST BED
f f f ,
ACID
PUMP
0
FILTER
€P
AUXILIARY
PUMP
i/n-t
/ \ / SAT.
/ \ /
/ \ /
y
4 EXCESS WATER
^"^^^^^~
10% HzSO*
1 ^
l v
i \
J
S Ss's'/s's'S's' // //
CATALYST BED
t
OIL. H2S04.
•>TO ACID PLANT
CLEANED
GAS
Q) FAN
I I
a
ts
s
USED ON JOB |
RECYCLE
PUMP
USTOFPMTl
CNEMCAL CONSTRUCTION CORPORATION
COWULTtHG. DOKHING AMD CdrnuCTING nKfflflM
TAIL GAS SCRUBBING PROCESS 2.2.22
CATALYTIC CONVERSION OF SO2
& WATER TO DILUTE H2SO4
SULFACID PROCESS
ISSUED FOR CONSniUCnON
AUTHOMZATKM HO.
0064 C
FIG 21
-------
CONSULTING DIVISION
evaporated in the venturi concentrator.
In addition to water limitations, the tail gas entering the catalyst bed must
o
be saturated to a minimum temperature of 125 F. This requirement may
be met by injecting low pressure steam and some water downstream of
the concentrator in a 2-stage quencher. Steam and water saturation are
required for plants 96% and over in efficiency. With less efficient plants
the tail gases would be heated to the point where concentration alone would
produce a saturated gas at 125 F.
Further development work is being carried on by Lurgi to raise the con-
centration of the dilute 10% acid now produced. If successful this should
substantially reduce one of the major technical drawbacks of the process
in its present form.
The necessity for using supplementary heat to concentrate the product to
usable form is a serious economic drawback. The alternative to adding
heat would be to neutralize and dispose of surplus dilute acid - an
undesirable prospect. When large gas volumes or gases with high SO0
o
concentrations must be handled structural problems arise in the reactor
design in connection with support of the catalyst bed. This point may or
may not be reached if a Sulfacid unit were designed for a very large acid
plant or one with a high emission level.
While most other tail gas recovery processes will handle increased SO2
loading resulting from plant operation in excess of design capacity with
improved economics, the Sulfacid process in its present form would
offer no advantage in this area. Control effectiveness is limited by
inlet SO0 level as well as gas volume.
^
IV - 38
-------
CONSULTING DIVISION
The Sulfacid process also has some distinct advantages, probably the most
important being that it is in actual commercial operation. In addition, it
is a relatively simple process with only minor mechanical equipment
which should give it a high on-stream factor.
In addition to increasing product acid strength, development of a catalyst
which would permit the oxidation in the reactor to be achieved at higher
gas velocities would improve the process.
IV - 39
-------
TABLE 11
ESTIMATED CHARACTERISTICS OF A 250 T/D H0SOJ PLANT
WITH 2. 2. 22 "SULFACID" TAIL GAS TREATMENT
UNDER VARYING ACID PLANT EFFICIENCIES
Sulfacid Process Conditions
Acid Plant Conditions
Conversion
Efficiency
_%_
99
98.5
98
97.5
97
96.5
96
Tail Gas Make-Up H2O
S
Lbs/Mih * %_
3.24 24.4
4.87 16.4
6.49 14.1
8.12 13.1
9.73 12.5
11.35 12.0
13.0 11.7
Acid Plant Product
Tail Gas Flow
Tail Gas Temperature
Ambient Air Humidity
Raw Material
SO, Recovery Efficiency
Water Available for Make-Up Supplementary Heat Requirements
Before Cone. After Cone, in Water to be Heat
in Venturi Venturi (2) Evaporated Req'd
Lbs/Min Lbs/Min Lbs/Min Btu/Min
29.2 10.1 0 0
43.8 24.7 0 0
58.4 39.3 0 0
73.1 54.0 12.4 16,200
87.6 68.5 26.9 35,800
102.2 83.1 41.5 58,000
117.0 97.9 56.3 81,000
98% H SO
18,70(TCFM
154°F
.02 Ib. H O/lb. Bone Dry Air
Sulfur
95%
Equiv. Recycle
Nat. Gas Acid Cone.
SCFM _%_
0 10
0 16.4
0 14. 1
16.2 16.3
35.8 19.0
58.0 21.4
81.0 23.8
(1) Based on Scrubbing with 10% Acid with no Supplementary Heat
(2) With no Supplementary Heat
(3) To
Raise Inlet
Temperature to Reactors to 125 F, Saturated
Gas Saturation
Requirements (3)
Steam
@ 50 psig Water
Lbs/Min Lbs/Min
113
113
113
98
79
59
37
15
15
15
13
11
-------
CONSULTING DIVISION
Absorption with Basic Aluminum Sulfate Solution, Regeneration with Heat
to Release SCX (Hardman-Holden) (2.2.28)
^
This is an old chemical absorption process (Figure 22) in which basic
aluminum sulfate solution reacts with SO? to form a complex compound.
vapor is also absorbed, but the mist is likely to pass through un-
o
touched, and should be removed before the gas is treated. The SO_ is
recovered by steam stripping the solution, condensing the excess steam,
and recycling the wet SO gas to the plant. The- SO pick-up, and build-
£* O
up, in the absorbent solution is controlled by reacting a side stream of
the stripped liquor with calcium carbonate. The sulfate is filtered off.
The calcium content can be further reduced by adding some sulfite rich
solution to the filtrate and polish filtering the product before recycling.
The major disadvantage of the process is the corrosive nature of the
absorbent. A second potential problem is the precipitation of insoluble
complex compounds in the packed towers. The solution is meta stable
through certain of the operating temperature-composition ranges.
Methods of preventing or minimizing the effects of these precipitates
have not been demonstrated commercially.
The Hardman-Holden process is presently in operation in Europe, in
connection with a sulfur dioxide producing plant. The process can
be expected to achieve a control effectiveness of 200 ppm and possibly
lower. The SO9 content of the feed gas stream does not effect the
sizing of the equipment. To achieve a greater control effectiveness the
only change necessary is to increase the height of the packed section of
the absorber. Steam consumption is lower than many other steam
stripping processes.
IV - 40
-------
TAIL GAS
rROM ACID PLAi
CiSQ.
TO DUMP
(
DESORBER
4
\
c
»
•->.
Y
STEAM
ROTARY
FILTER
•f— - O
r_ L
C<
Vi—
/
c,
f
^
?P
^
U_
TO STACK
DRYING
VACUUM
STRIPPER
WASTE
n
kr
INHIBITOR
STORAGE
FEEDER
y
^- AGITATED^*
SOLUTION TANKS
CKEKCAL OMSTRUCTION CODPOlixTION
TAIL GAS RECOVERY PROCESS 2.2.38
ABSORPTION WITH BASIC ALUMINUM SULFATE
SOLUTION, REGENERATION WITH HEAT TO
RELEASE SO; (HAROMAN-HOLDEN)
~ 0064 C FIG. 22 P
-------
CONSULTING DIVISION
The most troublesome of the tower fouling problems is the deposition of
calcium sulfate in the inlet tower in the absorption train. This precipitate
cannot be removed by chemical means. Present thinking leans to a pair
of short gypsum packed guard towers which can be dumped every few
months. The mechanisms for the precipitate formation are not under-
stood.
The liming step for sulfate removal leaves the solution saturated with
CaSO .. The incoming gases contain some SOQ and also the SO9 in
™i O ^
solution reacts to form SOQ with dissolved oxygen. The increase in the
o
sulfate level precipitates the calcium though why it is confined to the
first tower is not known. The SO_ oxidation is catalysed by these
£
compounds which are continuously removed by reaction with copper sulfate.
Similar sulfate removal problems must occur in other alkali absorption
systems. Liming for sulfate removal may be expected to cause the
same problems in the absorption towers. Ion exchange may be economic
in other systems, but the basic aluminum sulfate system cannot tolerate
more than traces of the monovalent alkalis.
The on stream factor for process 2. 2. 28 is likely to be lower than that
of the acid plant due to fouling problems. The space requirements for
this process are comparatively high, being in the order of 4, 000-5, 000
square feet for a 250 T/D H?SO plant. The systems will require the
attention of a full time operator.
While this process has been in commercial operation for over 30 years,
very little has been done to improve its operation. Development work
would be required to find a suitable method for initial removal of SOQ
o
and acid mist and to reduce the fouling problems.
IV - 41
-------
CONSULTING DIVISION
Resin Adsorption Process (2.2.29)
This process is illustrated by Figure 23.
The collector for the acid components of the gas stream is a polymer
containing basic groups along its chain. The marco structure is such that
diffusion into the core of the 20 mesh granule is very rapid and subsequent
diffusion through the solid polymer of the matrix is sufficiently rapid to be
economic in gas phase adsorption. The heats of adsorption depend on the
acid component involved.
SO can be desorbed by heating to about 220 F. The bonding with SO
is such that thermal desorption is impractical and chemical means must
be employed.
The economics of the recovery of SO from acid plant tail gases dictate
&
the removal of the H0SO . or SO before the adsorption of SO0. A separate
Z 4 u £
resin bed could be used for this purpose which bed would be periodically
regenerated chemically. A more direct approach is the reaction of the
SO with a chemical such as lime or soda ash. The chemical reagent
«J
can, in theory, be in aqueous solution but sulfuric acid mist is expensive
to remove by such media. The alternate is preheating the gas to
evaporate all mist and passing it through a bed of highly porous lump
lime or soda ash briquettes whereby gaseous SOQ reacts with the solid.
O
In view of the very high ratio of SO to SO_ the adsorption media trans-
Ci O
forms first to the sulfite and then to the sulfate. The kinetics of this
approach are under investigation.
IV - 42
-------
1.1
IR
s
TO ATMOSPHERE
DRY AIR FROM
DRYING TOWER
TAIL GAS
BLOWER
ACID PLANT
TAIL GAS STACK
USED ON JOB
I I
ACID MIST AND
S03 REMOVAL
S02 ADSORBER
AIR+ 502
•> TO SULFUR
FURNACE
RATON
TAIL GAS RECOVERY PROCESS 2.229
RESIN ADSORPTION OF S02
0064C
FIG.23
-------
CONSULTING DIVISION
The SO^ is adsorbed on ;the resin at about 100 F and stripped off at about
200-220 F. To simplify the stripping process a dried acid plant air
i
stream is passed through the bed and returned to the acid plant.
Resin life has not been firmly established but appears to be about two
years based on laboratory work. The life depends strongly on the
regeneration temperature as might be expected for an organic compound.
Its degradation rate is not a simple function of its residual capacity and
the function itself may change with regeneration temperature suggesting
a strong dependence on the exact local polymer structure.
The system has not been piloted. Laboratory development to date has
been conducted by Rohm and Haas, who hold the patents for the resin.
The resin has an adsorption capability to achieve theoretically, a
control effectiveness of near zero ppm SO The process is unaffected
^
by the inlet SO9 concentration, higher concentrations simply requiring
^S
more frequent resin regeneration. An actual control effectiveness well
below 100 ppm is expected.
The process is simple and essentially automatic, requiring only part
time operator attention. Space requirements for a unit to handle a
250 T/D acid plant are about 2, 000 square feet.
IV - 43
-------
CONSULTING DIVISION
Lime Absorption of SO2 (2. 3. 3)
This is one of the simplest and most straight forward of the feasible
processes. Variations of it are in commercial operation on utility
power plants.
The objective of this process is to absorb the SO in the tail gas with an
inexpensive alkali and then dispose of the sulfur salt, as illustrated by
Figure 24.
Sulfur dioxide, SO_ and acid mist are absorbed in a single-stage venturi
O
type scrubber. The scrubbing liquid is a slurry containing hydrated
lime, calcium sulfite and sulfate. The reactions in the scrubber are
as follows:
Ca(OH)0 + S00 + H0O >CaSO_.2H_O
& CaSO 2H O
£ O £t TC &
Ca(OH) + H2SO4 >CaSO4. 2H2O
CaSO 2H2O + !/2O2 >CaSO 2H O
Following absorption the slurry is held in a delay tank to desuper-
saturate any calcium sulfate. This is done to avoid scaling out of this
salt in the lines and the scrubber.
The bleed stream is drawn from the scrubber system to separate the
sulfur salts equivalent to the sulfur gases being absorbed. Sulfite,
sulfate and some alkali are settled out in the clarifier.
The underflow is centrifuged and the wet solids are sent to a storage
hopper for disposal. The mother liquor is sent back to the scrubber
IV - 44
-------
r
|s
• c
5 S
I
If
I!
\-
5
is
.
«'
I<
•
s
B •
Js
• t
*!
i s
X ».
3
-
|'
r-
.
£ •
2°
3
o
-
f*
^j
u
FEEDER 1
-------
CONSULTING DIVISION
along with the overflow from the clarifier. Lime and make-up water are
added to the scrubber system via a slaking tank:
CaO + H20 >Ca(OH)2
An area in this process which may present processing problems is to
achieve maximum utilization of the alkali which would be indicated by
a very small percentage of free alkali in the waste solids.
Scaling of calcium sulfate must be investigated and proper delay times
need to be established.
This process is simple, physically small and relatively inexpensive for
a tail gas scrubbing process. The space requirements for a 250 T/D
plant are only about 1, 000 square feet. It may prove advantageous for
small acid plants, for which the lime consumption and gypsum disposal
would be minimal.
This process, unlike SO_ recovery processes for tail gas clean up,
Li
does not give any incentive to push an acid plant to its maximum
capability, since unreacted SO is converted to a waste product rather
Li
than returned to the plant.
Process 2.3.3 requires only part time operator attention and should
have a high on stream factor.
This process would be a useful back up to other scrubbing processes for
use when a regeneration system is shut down. A stand-by storage tank
for lime slurry might permit the acid plant to continue operation with
good emission control until the regeneraor is back on line.
IV - 45
-------
CONSULTING DIVISION
Ammonium Sulfite-Bisulfite Absorption with SO? Recovery and NH NO,,
Production (2.4. 5)
This process, as illustrated by Figure 24, recovers most of the acid plant
sulfur emissions as SO for recycle to the plant and a small part as ammonium
^
sulfate in an NH NOr-(NH ) SO solution, containing about 16% N which might
rr o rr Z 4
find a market locally as fertilizer. Sulfur dioxide is absorbed in two
stages with ammonium sulfite-bisulfite solutions which are subsequently
reacted with nitric acid to form ammonium nitrate and SO2. The SO
is recycled to the acid plant and the ammonium nitrate is prepared for
sale. Basically, this process is one of providing for the absorption of
SOQ from an acid plant tail gas as an intermediate step in the production
£
of ammonium nitrate.
SO0 is absorbed with the conversion of sulfite to bisulfite:-
L*
+ H20 > 2NH4HS03
Amounts of bisulfite and sulfite equivalent to the SO absorbed, minus
^
the small amount of sulfite oxidized to sulfate, are bled from the
absorption part of the system, mixed with nitric acid and passed into
a steam heated reactor where the following reactions occur:-
NH HSO + HNO ^ NH NO + SOQ + HO
~to o 4 o £ £
(NH4)2SO3 + 2HNO3 > 2NH4NO3 + SO2 + H2O
The SO? recycle steam is indirectly cooled to about 110 F before it is
returned to the acid plant. The ammonium nitrate solution containing
a small amount of ammonium sulfate from acid mist and SO as well
O
as from sulfite oxidation, is concentrated in a vertical tube evaporator
to a 45% NH4NO3 for sale.
IV - 46
-------
TAIL GAS
j
1
MIX
TA
4
STEAM
H;0 & OXIDATION INHIBITOR
CONDENSER,
SOj TO ACID PLANT
REACTOR
REGENERATION
COLUMN
AMMONIUM NITRATE
SOLUTION STORAGE
•— t
STORAGE
Ta
^
CN HU)2 S04
HjO
CONCENTRATED
SOLUTION
6m. V.
DILUTE AMMONIUM
NITRATE SOLUTION
-STEAM
SOLUTION CONCENTRATOR
VERTICAL TUBE EVAPORATOR
•CHOUUL CONSTRUCTION CORPORATION
TAIL GAS SCRUBblllfa PROCESS 2.1.5
AMMONIUM SULFITE-BISULFITE
ABSORPTION WITH S02 RECOVERY *ND
NhUNO, PRODUCTION
0064 C
FIG.25
-------
CONSULTING DIVISION
Ammonia feedstock is added to both absorption stages to convert excess
bisulfite to sulfite since one mole of SO9 produces two moles of bisulfite.
NH4HS03 + NH3 >(NH4)2S03
Although this process is in operation in Europe, certain points require
confirmation for complete evaluation. As with similar processes an
oxidation inhibitor to minimize sulfate formation should be found.
The absorption stage should be piloted to confirm that the required SO2
absorption can be achieved without significant loss of ammonia. The
nitration reactor which is now being operated by the North Bohemian
Chemical Works (SCHZ) at Lovosice, Czechoslovakia should be
evaluated.
Since the by-product fertilizer solution is dilute and not a normal
commercial grade, a market would have to be found within an economic
distance from the plant. This will tend to restrict the number of
potential applications of this system.
While this process is not particularly complex, the regeneration reactor
column and vertical tube evaporator require careful attention and may
tend to reduce the on stream factor somewhat; nevertheless, the
process operates independently of the acid plant and will not affect its
operation directly. Additional operator time equivalent to one man per
shift should be allowed.
Space requirements for a plant sufficient for tail gas treatment for a
250 T/D acid plant is 2, 000-3, 000 square or more, depending upon
NH~ and product storage requirements.
IV - 47
-------
CONSULTING DIVISION
Sulfuric Acid-Lime 2-Stage Absorption to Recover SO2 and Produce
Plaster of Paris (2.4.6)
This process has neither been operated commercially nor piloted as a whole,
though individual sections have been piloted. It is designed to achieve a
control effectiveness of 100 ppm, removing SO , SO., and acid mist to
u O
produce a salable plaster of paris (CaSO.. 1/2H O) and recycle a portion
4 £A
of the SO to the H SO plant.
£ & Tt
About half of the SO9 removed from the tail gas is oxidized to sulfuric
acid in a first absorption stage and the remaining half is absorbed with
lime in a second stage to form calcium sulfite. The s ulfite is then
reacted with the sulfuric acid from the first absorption stage to form
calcium sulfate and SO0, the remaining half of which is recycled.
In the first stage the SO is catalytically oxidized to sulfuric acid in the
presence of a small amount of manganous sulfate. Acid mist and SO9
are also removed at this point. The acid concentration is maintained
at about 10% and this is reacted with the calcium sulfite slurry coming
from the second absorption stage. An oxidation inhibitor may be added
to the second stage to minimize sulfate formation. Any calcium sulfate
formed here represents a loss of recycle SO9 as well as an excess of
dilute acid which must be disposed of.
Batch reactors are used for the conversion of calcium sulfite and
sulfuric acid to gypsum and SO9. The evolved SO is indirectly cooled
£i &
to about 110 F before it is recycled to the acid plant. The gypsum
slurry formed is centrifuged and then dried at about 260 F. The
dried material is ground to a fineness of 70-80% through 100 mesh
before being sent to a reactor where the gypsum is converted to
IV - 48
-------
FIRST STAGE
SECOND STAGE
STORAGE-PLASTER
OF PARIS
NAT.
GAS
AIR
1 ,
H20
L
<
STORAGE
HOPPER
KETTLE
—
N
V
E
Y
0
R
GRINDER
COOLING
PIT
DRYEH
S02 TO
*ACID PLANT
TAIL GAS SCRUBBING PROCESS - 2.4.6
SULFURIC ACID-LIME 2 STAGE ABSORPTION
TO RECOVER SO, AND PRODUCE
PLASTER OF PARIS
0064 C
T~
FIG. 26
-------
CONSULTING DIVISION
plaster of paris:-
Ca SO . 2H O _ s CaSO . 1/2H O + 3/2H-O
4 £ 4 £ £
Natural gas is used as the fuel for the drying as well as for the
conversion to the hemihydrate.
Several potential processing problems are apparent in this
process. The catalytic oxidation of SO^ in the first stage should be
proven. A suitable oxidation inhibitor should be found for the second
stage.
In addition to processing problems, a market for plaster of paris would
be required to make this system economically attractive.
A batch reactor system which would require more than one additional
man per shift plus a complex process makes this process less
attractive than several others unless a market for CaSO.. 1/2H?O is
available nearby. The control effectiveness is potentially high, but
the on stream factor will probably be lower than the acid plant,
although this will not affect the acid plant directly since the process
operates independently.
IV - 49
-------
CONSULTING DIVISION
D. FEASIBLE SYSTEMS FOR SO,, AND ACID MIST CONTROL
Several processes which are feasible for SO_ control will
£t
simultaneously provide control of acid mist and SOq, either by
o
choice or because the nature of the process requires that SO,,
and acid mist be removed prior to the removal of SO2. Aside
from these processes there are several processes and devices
which are feasible for SOQ and/or acid mist control, and which
o
are suitable for application to sulfuric acid concentrators
(process classifications 1. 5 and 2.5) or to plants with dual
absorption systems which do not themselves reduce the acid
mist problem as the SO9 emission level is reduced.
^
Many plants now operating incorporate pad type mist filters as
described in 3. 1. 1 and which very economically reduce the level
of acid mist emission as low as 2 mg/SCF, and remove essential-
ly all particles -^ 3 microns. Removal of mist particles of < 3
microns is more costly, but not especially difficult, several
feasible systems being available.
The feasible processes are listed in Table 12, which shows the
removal efficiency for that portion of the mist above and below 3
micron particle sizes, and the emission level which may
reasonably be expected for acid plants and for oleum plants,
expressed in milligrams per standard cubic foot. The mist
characteristics of these plants have been described in Part III.
The aim in mist removal has been to eliminate a visible plume
from the plant stack. Particles smaller than 3 microns will tend
to form a visible plume at much lower quantitative emission
IV - 50
-------
CONSULTING DIVISION
levels, thus the desirable control level varies with the characteristics
of the mist at each plant. Mist forms from 10% to 30% of the total
sulfur emission, and when uncontrolled it is often a real problem.
The various feasible methods included in Table 12 and described on
subsequent pages, are:-
3. 1. 1 Dual Pad Mist Separators
3.1.2 Tubular Type Mist Separators
3. 1. 3 Panel Type Mist Separators
3.2. 1 Electrostatic Precipitation
3. 3. 1 Mist Removal with Venturi Scrubber
The control of SOQ can be accomplished with these devices only if
O
moisture is added to first convert the SO to H SO mist. This
O ^j ft
occurs in a scrubber, such as process 3. 3. 1, but not with the other
devices. Addition of moisture in these devices may introduce a serious
corrosion problem, and seems to require time for the mist to form.
Introducing the exact stoichiometric water requirement is difficult
because of variation in SO_ content. A method of introduction to
achieve proper distribution could also be a problem.
IV - 51
-------
TABLE 12
Process
3.
3.
3.
3.
3.
1. 1
1.2
1.3
2. 1
3. 1
FEASIBLE
Efficiency
_>3 microns
99+%
100 %
100 %
99 %
98 %
SYSTEMS FOR ACID
Efficiency
<3 microns
15 - 30%
95 - 99+%
90 - 98%
Near 100%
Low
MIST CONTROL
Emission Level
99% Acid Plants*
to 2 mg/SCF
0. 1 mg/SCF
0. 5 mg/SCF
0. 5 mg/SCF
3 mg/SCF
Emission Level
Oleum Plants *
to 5 mg/SCF
0. 1 mg/SCF
0. 5 mg/SCF
0. 1 mg/SCF
Ineffective with
<3 micron mist
* Based on manufacturer's generally expected results.
-------
CONSULTING DIVISION
Dual Pad Mist Separator (3. 1. 1)
This is a simple, effective device in common use for removal of acid
mist from absorption tower stacks. Generally, when operated at
proper velocities, it will remove essentially all of the mist
particles of 3 microns or larger.
Usually two pads are arranged horizontally in series in a section of
reduced diameter atop the absorption tower, on top of which the stack
is supported. Pads may be from 4 to 12 inches thick and are of
knitted stainless steel wire or of teflon for H SO. service, supported
o ~z
on a stainless steel grid. The only operating cost is the power required
to overcome the 2-3" W. G. pressure drop through the separator.
Entrained droplets and mist impinge on the mesh and are held
momentarily, permitting larger drops to form which run off and fall
back into the tower. Mist particles smaller than 3 microns, however,
tend to pass through, only 15-30% being recovered. This type of unit
is not as effective on plants with larger quantities of very fine mist
such as occurs in an oleum plant.
Installation is relatively simple in existing plants as well as new
plants, and requires no additional plant area, no additional operators
and does not affect plant on stream factor.
IV - 52
-------
CONSULTING DIVISION
Tubular Type Mist Separator (3.1.2)
This type of unit consists of multiple vertical tubular elements formed from
packed glass fibre hung from a tubesheet located in the top of the acid plant
absorption tower, or for an existing plant, often in a separate vessel which
may be located on top of the absorption tower if conditions permit, or adjacent
to the absorption tower at grade, or in the base of the stack.
This type of unit is very efficient, and since they are designed so that
Brownian movement is the controlling mechanism for mist collection,
smaller particles whose Brownian movement is greater, are collected
with high efficiency, so that visible plumes may be eliminated even from
oleum plants. The efficiency of this device is affected very little by gas
velocity. Pressure drop through the mist separator element is on the
order of 8" W.G. ; however, the total pressure drop of the system depends
upon the arrangement used.
When installed in an absorption tower, the tower height must be increased,
or a separate vessel of similar construction provided to house the filter
elements. The elements are of glass fibre, but ceramic elements have
also been used. Droplets fall by gravity down the inside of the tube and
are collected in a seal pot. The collected acid either falls or is pumped
to the absorption tower depending upon the arrangement used. When an
external vessel at grade is required, the cost of the system is sub-
stantially increased since a foundation, acid reservoir, acid pump,
ductwork, and often a booster fan must be included.
Variation in packing materials and density can provide a variety of
removal efficiencies in the <" 3 micron range, but at very little
differential cost.
IV - 53
-------
CONSULTING DIVISION
Panel Type Mist Separators (3.1.3)
This type of unit consists of a many sided chamber situated in the top of
an absorption tower or in a separate vessel. The vertical sides are
provided with glass wool panels and the bottom is a steel plate sloped to
drain collected acid toward the center of the chamber. Tail gas enters
from the outside and as it passes through the elements droplets collect
on the inner side of the panels, fall by gravity to the bottom and are
returned to the absorption tower.
The unit is very efficient for most applications except for very strict
control of oleum plants. Pressure drop through the elements is low,
(6-8M W. G.) but total pressure drop depends upon arrangement.
For new installations the unit can be accommodated by extending the
absorption tower height to include it. In this case, collected acid is
returned directly through a drip leg. For existing plants, however, it
is usually necessary to provide a separate vessel for the separator and
to pump collected acid back to the absorption tower. A booster fan
would probably be required, as well.
As with other mist control devices, this is very reliable, requires no
attention and little maintenance.
IV - 54
-------
CONSULTING DIVISION
Electrostatic Precipitation (3. 2. 1)
This type of equipment has been used for satisfactory mist control for
many years in the purification section of wet gas plants, and was also
used on drum concentrators for mist and spray control. These devices
were lead lined with vertical tubes, lead being required because of the
corrosive nature of dilute HQSO . Recently a variation of this equipment
£ ~r
has been used successfully on tail gases from acid plants. For this
service, the equipment is constructed of mild steel with long vertical
panels dividing the precipitator shell into ducts which are charged to
attract mist particles.
This equipment is most effective on the smallest mist particles, and
can be provided with overall efficiencies up to 99%. Electrostatic
precipitators should be very effective on oleum plants. Velocities
must be low, 3-5 feet/sec. , but pressure drop is usually less than l"
W. G. , which means that no auxiliary blower is likely to be required.
Efficiency is increased by increasing the length of duct, or residence
time. Power requirements are nominal, ranging from 25 KVA for a
50 T/D acid plant to 90 KVA for 1, 500 T/D.
One drawback is relatively large physical size of the equipment,
ranging from 5' x 11' x 25' H for a 150 T/D plant to 30' x 30' x 40' H
for a 1, 500 T/D unit.
For drum concentrator applications lead lined electrostatic units have
been supplanted by venturi scrubbers which are less costly, although
they continue to be used in wet gas purification.
IV - 55
-------
CONSULTING DIVISION
Venturi Scrubber (3. 3. 1)
This is the same general type of unit as is employed in many tail gas
recovery systems, and depends upon intimate contact in a restricted
throat between the tail gas and sprays of circulated liquid to mechanically
remove the mist. This type of unit is flexible as to capacity and is quite
effective with mist>3 microns. It is not likely to be effective, however,
on very fine mist which tends to behave as a gas. Many of these units
are in operation on concentrators where mist is generally 3 micron and
larger. The scrubbing medium for concentrators is weak acid which is
gradually bled to the concentrator as makeup.
This equipment is very reliable and requires no additional operator
attention. It is not large, but in most cases separate installations at
grade would be required, as the unit does not lend itself for installation
on an absorption tower.
IV - 56
-------
CONSULTING DIVISION
E. EMISSION CONTROL FOR CHAMBER PROCESS ACID PLANTS
As has been shown in Part III, chamber process acid plants are relatively
few in number, relatively small in capacity and have an emission
problem which is different from the contact process plants, requiring
different control processes. Emissions from chamber plants can be
as much of a problem as those from contact plants. Because the
chamber process is gradually disappearing little effort has been
expended on control of this dual emission problem of sulfur dioxide
and nitrogen oxides. Processes applicable to contact plants are not
suitable for removal of nitrogen oxides and, likewise, processes
applicable to nitric acid plants for NOX control are not best for SO
£
control. Mist loadings are similar to those for non-oleum contact
plants, and the same types of mist control devices are applicable.
In the process survey, three processes have been received for control
of this dual problem, none of which may be considered feasible at
present. A cursory review of the control cost for process 4. 1. 3,
when applied to a rather large capacity chamber plant, gave a
control cost of over $8 per short ton, far in excess of the control
costs for contact plant control processes. (Control cost is defined
in Part V. ) Based upon this finding, it is considered very doubtful
that a chamber acid plant, if faced with a choice of installing a
control system or shutting down, could justify economically the
installation of a control system.
Moreover, from Table 1, we can see that very few chamber acid
plants are located within designated AQCRs. We have removed
them from detailed consideration in this section.
IV - 57
-------
CONSULTING DIVISION
F. COMPARISON OF SYSTEMS
As for any other process or device, technical considerations for
selection of an acid plant emission control system will include:-
Technical capability to achieve the required control
effectiveness - by actual demonstration preferably.
On-stream reliability.
Simplicity.
Flexibility to handle varying concentrations; also, to
be modified if necessary to comply with more
stringent regulations in the future.
Of Lesser Importance
Installation will not interfere with acid plant operation.
No unfamiliar operations are required.
No new disposal problems are introduced, either of
waste material or salable by-products.
Small space requirements.
An ideal system, in addition to all of the above, would require
minimum operating cost and be applicable to all types of acid
plants. At present, no such system has been developed.
It should be emphasized that the criteria for selection of a
control system for application to a sulfuric acid plant are not
necessarily the same as for other applications where gas flows,
IV - 58
-------
CONSULTING DIVISION
compositions and temperatures are different and whose general operation
are of a different nature, such as power plants and the like.
The systems described in this report fall into three general groups,
the general capabilities of which are described and compared below.
In Plant Modifications for SO0 Control
^
All dual absorption systems control SO emissions only, and provide no
4U
control in themselves for SOQ and acid mist. Their application is more
o
limited than tail gas recovery systems, principally being applicable to
sulfur burning plants. Their control effectiveness is expected to
be better than 500 ppm. Application of dual absorption to an existing
plant will require a careful study of space, accessibility for construc-
tion, and other factors of arrangement and design. Each installation
will require individual, detailed engineering. They cannot be further
modified to achieve a greater control effectiveness.
Dual absorption systems, on the other hand, present several distinct
advantages to existing plants which can use them. The technology is
conventional sulfuric acid technology which is presently offered with
guarantees, commercially. Their on stream reliability is identical
to that of the plant to which they may be applied. Flexibility of the
acid plant itself will be increased, since the plant may be pushed to
its maximum capability and still maintain a control effectiveness of
500 ppm. This is especially true for older, less efficient plants
with large design safety factors, which might take excellent advantage
of this possibility.
IV - 59
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CONSULTING DIVISION
A new plant, designed for dual absorption from the start, will,
additionally, through process design modifications, be able to take
advantage of reduced sizes of major equipment. Such a plant will be
simpler and less costly than an existing plant with an add-on system.
With a new plant the arrangement problem of the add-on system is
avoided.
The methods described in 1.3.4 for improved conversion meet all of
the criteria technically required for the ideal system except one --
they cannot achieve a control effectiveness in the range being considered
as a permissible emission level. It is possible that a reduction in plant
capacity using these criteria to achieve, say 1, 500 ppm, may result in a
greater production cost per ton of acid than to build an "add-on" dual
absorption system and run a plant at 25% above design capacity with a
control effectiveness of 500 ppm.
Older plants, plants with multiple units, and wet gas plants tend to be
more congested or hemmed in by other facilities, and probably would
have difficulty in finding space within battery limits for in-plant control
systems. An installation which would require extensive modification
to existing facilities would require prolonged shutdown and would be
prohibitively expensive.
Tail Gas Recovery Systems
Most tail gas recovery processes provide simultaneous control of SO ,
^
SOQ and acid mist to levels well below 500 ppm under ordinary plant
O
operating conditions. The tail gas recovery processes are generally
applicable, from the technical standpoint, to all classes of contact acid
plants. Their greatest drawback technically at present is that most
are not completely developed.
IV - 60
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CONSULTING DIVISION
While tail gas recovery processes may or may not have the on-stream
reliability of the H9SO. plant with which they may be associated, this is
^j ~r
not critical since such processes are not an integral part of the acid
production process. If they are not operating the acid plant may
continue to operate, but tail gas emissions will return to the condition
existing before the control system was installed. Whether or not this
is acceptable will depend upon local regulations. They also will have the
considerable advantage of providing good control during the awkward
periods when an acid plant is starting up or shutting down.
Generally, such systems are flexible with respect to the concentration
of sulfur compounds in the tail gas which they can handle, although with
high concentrations the SO9 emissions may increase slightly they are
£1
still expected to be within presently proposed limits under almost all
conditions.
In most cases, tail gas recovery processes are more complex than any
type of in-plant process modification and will require additional
personnel to operate. In this regard, those processes which produce
by-products of any kind are the least desirable if other considerations
are equal. The exception, of course, would be a plant in a unique
situation where a convenient market at a good price existed for a given
by-product.
Where an acid plant consists of several units together, all of -wh ich
will require control systems, tail gas recovery systems may be very
attractive economically. This is discussed in more detail in Part V.
IV - 61
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CONSULTING DIVISION
Tail gas recovery processes do not need to be integrated into the sulfuric
acid plant battery limits, although it is desirable that they be located
nearby. Only the SO removal scrubbing portion of a process need be
^
adjacent to the acid plant absorption tower. From an operational and
mechanical standpoint it would not be desirable to locate the scrubbing
section on top of the acid plant absorption tower.
Tail gas recovery systems will not need the careful individual design
that add-on dual absorption requires; they can be fairly standardized
package systems. For a group of units in one plant it would be logical
and advantageous to install a scrubber on each unit with one centralized
recovery .system. Generally, tail gas recovery systems will require a
larger area than the in-plant conversion systems.
By-product producing processes, aside from economic considerations,
appear less desirable than those which recover SO9 or acid for recycle
^
to the acid plant. By-products which have been considered in the
"feasible" processes are sodium sulfite, plaster of paris and ammonium
nitrate/sulfate solution. The location of markets, assuming they can be
found for these products, immediately limits the number of potential
applications for the process. In order to realize some recovery of
operating costs the producer must maintain some quality control, be
able to meet delivery commitments and provide the necessary additional
staff to perform these functions in addition to the actual handling of the
material.
The nitrate (or sulfate) solution produced in process 2. 4. 5 (or 2. 4.4)
is more dilute than conventional commercial solution fertilizers,
which immediately makes it less desirable, since twice the volume
IV - 62
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CONSULTING DIVISION
must be handled to acheive the same result as with commercial products.
Additionally, this is a highly competitive market dominated by large
producers.
Plaster of paris produced by process 2. 4. 6 will have a very restricted
market, probably the best potential being for gypsum wall board
producers. Another problem here will be the quantity of marketable
by-product. A wall board manufacturer is not likely to be interested in
a separate supply of a small fraction of his requirements.
Sodium sulfite, which was discussed with process 2. 1. 1, may have a
better marketability, but does not generally appear as attractive as
SO9 recovery.
^
Producing a waste product such as calcium sulfite-sulfate in process
2. 3. 3, although a nuisance is not likely to be difficult to dispose of in
the relatively small quantities under consideration.
In tail gas scrubbing processes water is evaporated and the gases are
cooled during absorption of SO . With processes using water slurries
&
or dilute salt solutions for absorption the gases become saturated. The
gases do not fully saturate, however, in processes employing concentra-
ted salt solutions. Cooling gases increase their density, reducing
effective stack height. The result is ground level SO9 concentrations
&
which are now as low as they would be if the tail gas was hot, but still
much lower than the concentration without a control system. Saturation
and near saturation of/the gases causes condensation and produces a
visible plume.
IV - 63
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CONSULTING DIVISION
It appears that it may be desirable to reheat tail gases in some instances
to reduce this problem. Several methods are available, such as direct
heating or indirect heating to reduce density and increase velocity. Heat
may be obtained from various sources including waste steam or
calciner tail gas.
In summary, the tail gas recovery systems which best appear to meet
the previously stated guidelines are, for each point:-
Technical Capability - Process 2. 2. 29 apparently has the
best potential for control effectiveness.
Most Advanced in Development - Are probably 2.3.3,
2. 2. 6, 2. 2. 8, 2. 2. 22 and 2.2. 28, although 2.2. 22 is
limited in potential applications.
Simplicity - Process 2. 3. 3.
Flexibility - Process 2. 2. 29 can achieve a control
effectiveness of near zero regardless of inlet SO
^
concentrations.
No Unfamiliar Operations - Processes 2. 3. 3, 2. 2. 22,
2. 2. 29, 2.2. 14 are best in this regard, although noe of
the "feasible processes" present very serious problems.
No Disposal Problems - Processes 2. 2. 6, 2. 2. 8, 2. 2. 14,
2.2.22, 2.2.28, 2. 2. 29 produce no waste or by-products.
Process 2. 2. 22 (Sulfacid) meets this condition only if all
dilute acid can be utilized within the plant.
Small Space Requirements - Process 2. 3. 3.
IV - 64
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CONSULTING DIVISION
Mist Control Systems
Mist control systems, like dual absorption processes, control only a
part of the total emission problem of contact acid plants. They can be
applied to any type of acid plant, and a majority of operating plants
today include some type of mist control device.
The effectiveness of various devices is governed to a large extent by
the particle size distribution of the mist in the tail gas stream as well
as the total quantity of mist. The on-stream factor for the feasible
systems is as high or higher than the acid plant to which they might be
applied.
All of the feasible devices reported are in commercial application on
acid plants, as well as other types of plants.
To achieve an invisible plume from most plants, 3. 1. 2, 3. 1. 3 and
3. 2. 1 can achieve the necessary control effectiveness. To achieve a
level of 3. 0 mg/SCF all of the feasible systems could be effective on
non-oleum plants. For oleum plants, however, 3. 1. 1 (dual mist pads)
or 3. 3. 1 (venturi scrubber) would not provide effective control, since
much of the mist is below 2 microns. Actual stack heights on existing
plants vary from about 60 feet to 300 or more feet above ground
level.
Tail gas treating systems which remove acid mist with or prior to SO9
Li
removal would in all likelihood reqa ire no further mist control, but
dual absorption processes will require mist control devices in addition
to dual absorption equipment. The type to be added, if any, would be
governed by the type of acid plant, as stated above.
IV - 65
-------
-------
CONSULTING DIVISION
V
ECONOMICS OF CONTROL
Preceeding sections of this report have dealt with the technical capabilities
and number of applications of various selected processes for
control of emissions from sulfuric acid plants. It is apparent that there
are several possible solutions to each problem which will achieve the
same effectiveness of control. Most control processes have wide
capabilities in the number and types of plants to which they may be
applied. The third factor which must be considered is the economics of
various control systems. To compare the various systems a comparison
is made of "control cost", which may be defined as the incremental cost
of H9SO . production contributed by a control system. Control cost is
C* ~t
determined by calculating the cost of producing one ton of acid in a
plant with a given control system, and subtracting the cost of producing
one ton of acid in the same plant without the control system, all on an
annual basis, and taking into account the increased production of the
more efficient plant with the control system. The cost of acid production
in conventional plants of various types is shown in Figure 12, Part III.
The cost of production in a new 2. 2 or 2. 4 class plant may be
considered the same as the production cost in modern 1. 2 or 1.4
plant for purposes of this study.
V - 1
-------
CONSULTING DIVISION
A. SELECTION OF UNIT COSTS
The various control systems utilize various chemicals which are
not normally used in acid plants. The unit costs used for these
various chemicals in calculating control costs are listed below:-
Ammonia
MnSO
Lime (CaO)
Plaster of Paris
(CaSO 1/2H O)
~t ^
Fuel Oil #6
MgO
K2C03
Oxidation Inhibitor
Ammonium Nitrate-
Ammonium Sulfate
Solution (16.7% N)
100% HNO (as 57%)
Natural Gas
Waste Disposal
Methylamine
Alumina
$ 50/short ton
$100/short ton
$ 15-16/short ton
$ 10/short ton
$. 07/gallon
$ 50/short ton
$.11/lb.
$1.25/lb.
$22.50/short ton
$ 80/short ton
$ 35/short ton
$ 33/short ton
$. 30/M BTU
$ 2/short ton
of disposable material
$. 20/lb.
$ 60/ton
V - 2
-------
CONSULTING DIVISION
B. SELECTION OF OTHER OPERATING COST FACTORS
For dual absorption systems of any type it is not likely that
additional operators would be required, since the equipment
operates in the same manner as the other equipment in the plant,
and requires no more attention. Add-on systems which are
separate processes will probably reqaire some additional
operator attention. Systems with mechanical solids handling
equipment and batch type operations require an additional full
time operator. When a by-product of some type must be
handled an additional part-time operator may be reqaired.
Simple processes and all gas-liquid systems will probably
require only part time attention by another operator. This
was discussed in more detail for each of the processes
described as feasible.
Maintenance costs for mechanical solids handling equipment
generally exceed the 4% figure used, but in these plants the
equipment represents a small part of the whole plant and
generally is operated at a fraction of its rated capacity,
therefore, we have held to 4% overall.
Overhead is taken as 70% of the sum of operating labor,
supervision and maintenance. This is approximately equal to
100% of operating labor, supervision and the labor portion of
maintenance, and has been used as a convenience in calculat-
ing control costs.
V - 3
-------
CONSULTING DIVISION
Interest, depreciation, taxes and insurance are charged at the same
rates used for the base plants. When applied to plants of classifications
1. 1 and 1. 3, interest and depreciation is included for the control
system cost only, since the plant is assumed to be over 10 years old,
and fully amortized.
V - 4
-------
CONSULTING DIVISION
C. CAPITAL INVESTMENT REQUIREMENTS
Since charges related to capital investment form a part of acid
production cost, including the cost of emission control, it was
necessary to prepare approximate cost estimates for each of the
processes described in Part IV. As the number of possible
combinations is practically unlimited, several examples were
selected for a variety of plant capacities and emission levels.
Costs for several systems were estimated for the same sets of
conditions so that results would be comparable. Recognizing
that other factors such as inlet concentration, control effective-
ness and plant capacity affect different processes in different
ways, cost estimates of selected processes were made under
different sets of conditions to permit the calculation of control
costs with respect to these other variables.
As the basic reference point a nominal plant capacity, (which
here means plant capacity at normal operating conditions
before inclusion of a control system) was selected at 250 ST/D.
Most processes were costed to fit three different classes of
acid plants, 1. 1, 1.2 and 1.4, as applicable, under the
following flow rates and emission levels:-
Class Emission Level Tail Gas Flow Rate
1.1 5,000ppm 18.700ACFM
1.2 2, 500 ppm 18,700ACFM
1.2 4, 000 ppm 18,700ACFM
1.4 3, 200 ppm 29.200ACFM
Very little was done with applications class 1. 3 plants, as it is
expected that the relationship in control costs between 1. 3 and
1. 4 plants will be similar to that between 1. 1 and 1. 2 for a given
control system.
V - 5
-------
CONSULTING DIVISION
For the design of the recovery process the tail gas was assumed to be
discharged at 154 F in all cases. Estimates are for approximate U.S.
erected costs under typical current conditions, exclusive of any site
clearing, land costs or royalties. Selected processes were also
estimated for nominal acid plant capacities of 50, 750 and 1, 500 ST/D.
Tabulations of these estimated capital costs are presented in Tables 13,
14 and 15. Similar information is presented graphically in Figure 27.
Process 2.2.22 is not included in the tabulation, since accurate informa-
tion was not available to permit estimating under the selected base
conditions. The only cost data available for 2. 2. 22 applied to an acid
plant is for a 396 T/D acid plant emitting 1, 800 ppm SO . This cost was
modified to add a quencher and convert to current U.S. basis. Control
costs for this process are calculated for this condition only, and are not
comparable to other control costs. 1, 800 ppm is not a realistic emission
level in the U.S. , and the cost variation of this process with SO« concen-
c*
tration was not available to us.
Variations in Capital Investment Requirements
Various factors which affect investment requirements, other than
capacity, were mentioned previously. The effect of these factors is
not always the same for all types of processes, as shown by the
following examples.
(1) Ellwood, Peter - "Versatility Is the Word For SO -Removal
Process" -Chemical Engineering, June 16, 1969
V - 6
-------
CONSULTING DIVISION
Variation With Acid Plant Capacity
With inplant modifications such as dual absorption, the cost of added equip-
ment all varies with plant capacity, since its sizing is basically determined
by gas flow through the plant. Tail gas recovery systems, on the other
hand, actually consist of two sections - a sulfur removal scrubbing opera-
tion whose size and cost is basically determined by the tail gas flow, and
a recovery section whose size and cost is governed only by the quantity of
sulfur values recovered. For example, a class 1. 1 250 T/D sulfur burning
plant, with a stack containing 5, 000 ppm SO0 in 18, 700 ACFM will require
^
the same recovery section as a 500 T/D plant with a stack containing 2, 500
ppm SO9 in 37,400 ACFM of tail gas. The scrubbing sections, however,
£
will vary by a capacity factor of two. This is true regardless of the
absorption process used. In some processes the absorption section is
large and the recovery section is small; in others the opposite may be
true. This is a cost factor which must be taken into consideration when
selecting a system for a specific situation.
From Figure 27 it may be seen that capital cost of control systems for
the same emission level vary widely with acid plant capacity. Process
2.2.29, for example, is low for small plants, high for large plants due
to the direct variation of resin requirements with acid plant capacity.
Process 2.2.6, on the other hand, is high for small plants but relatively
less expensive for large plants, for reasons discussed in preceeding
paragraphs.
Variation With Control System Capability
Some tail gas recovery processes, notably 2. 1. 1 and 2. 2. 6, may be
operated to recover SO only, or to remove SO plus SO., and acid mist.
£i £ O
V - 7
-------
CONSULTING DIVISION
Process 2. 2. 6, for example, will recover acid mist and SO,, along with
O
SO0 by a variation in scrubber design and an increase in the fan
LA
horsepower to overcome the additional pressure drop. The difference
in capital investment is slight, and the SO^-mist problem is reduced,
at an additional cost of perhaps $20, 000 for a 250 T/D plant, which is
less than 5% of the 2.2.6 control system cost.
Variation in Inlet Conditions to Tail Gas Recovery Systems
For tail gas recovery processes we have seen that the size and cost of the
recovery section of the process varies with the SO? content of the tail gas.
Since the quantities of material being handled in the recovery section of a
tail gas recovery process are very small by chemical plant standards,
the actual capacity of equipment very often may be greater than required
capacity simply because no smaller commercial continuous service
equipment is available. This is especially true for solids handling
equipment which is generally flexible in its capability to handle variations
in capacity. Since the tail gas scrubbing section is not affected at all by
inlet SO0 concentration, the overall result is that most processes vary
£t
only slightly in cost due to variations in inlet concentration. The
advantages resulting from this will be discussed under Control Cost.
For mist control systems the cost for any one type varies with flow
rate of the tail gas. With proper velocities most control devices will
achieve the same effectiveness, regardless of mist loading.
Variation With Control Effectiveness
In-plant modifications to achieve dual absorption will normally result in
a control effectiveness of 500 ppm SO?. Equipment size and cost
V - 8
-------
CONSULTING DIVISION
depends on plant capacity rather than on control effectiveness, and there
would be little, if any, cost reduction if a lower figure was chosen.
Tail gas treatment systems can vary in effectiveness by varying the
circulation in the absorption system. The only effects on capital cost
would be on the circulator pump size and the recovery section, which
would be changed only slightly. For example, to control from 4, 000 to
500 ppm rather than 4, 000 to 200 ppm would result in less than 10%
reduction in the capacity of the recovery portion of a tail gas control
system. Absorbant composition can also change effectiveness.
Variation Between Costs for Existing and New Plants
Generally application of a control system to a new plant will be less
costly than applying the same system to an existing plant, as well as
producing a more desirable plant arrangement, since the plot plan will
have provided for the control system at the outset.
Tail gas recovery systems, if included in the original design, may
eliminate the need for mist control devices on the absorption tower as
well as the need for a very high stack. It may be possible to eliminate
a separate fan in the absorption section of the control process.
When designing new plants using tail gas control systems which return
SO to the acid plant it may be possible to effect savings by reducing
,6
efficiency in the contact plant itself, as the sulfur losses are recovered
in the control system.
Mist control devices can be accommodated more economically on new
plants than old, principally because in new plants the devices may be
V - 9
-------
CONSULTING DIVISION
incorporated into the absorption tower, while for existing plants an external
installation is often required.
Capital Cost Savings for Multiple Units with One Control System
Tail gas recovery processes, which consist of a removal section and a
recovery section, can be applied to multiple acid plant units at one location
at a significant saving over installation of individual systems on each unit
of the acid plant. For this situation, a separate removal scrubbing or
absorption unit would be installed on each acid production unit. The bleed
streams for recovery would be treated in a single recovery section.
Significant savings would be realized in the capital cost of the recovery
unit, as well as reduction of design engineering costs.
V - 10
-------
TABLE 13
APPROXIMATE CAPITAL INVESTMENT REQUIREMENTS
FOR VARIOUS
SO,, CONTROL SYSTEMS APPLIED TO 250 T/D HnSO, PLANTS
Class 1. 1 Sulfur Burning
5, 000 ppm Emission Level
Add'l Acid By Prod.
Process T/D T/D
1.2.1 Dual
Absorption 11.9
1.2.2 Dual
Absorption
(1) 40.5
1.2.2 Dual
Absorption
(2) 11.0
1.2.3 Dual
Absorption
211 Na PO
ft . A, 1 iljil_v>*_» —
Absorption 19.5
2.2.6 MgO
Absorption 12.5
12. 5
2.2.8 KzSO3-KHSO3
Absorption 12.5
2. 2. 14 Methyl Amine
SO3-HSO3 Abs 12.5
2.2.22 Sulfacid
2.2.28 Basic Aluminum
SulfateAbs 12.5
11.8
2.2.29 Resin
Absorption 13.2 —
2.3.3 Lime No
Absorption — Value
2.4.5 Ammonium 30
Nitrate 6. 5 (sol'n)
2.4. 6 Acid-Lime
2 -Stage Abs 6.5 5.5
Control
Eff.
ppm
500
500
500
250
250
250
250
250
250
500
-0-
250
250
250
Capital
Cost
I
515,000
485,000
485, 000
630, 000
550,000
570, 000
610,000
475,000
700,000
670,000
395,000
295,000
650, 000
750,000
Class 1.2 Sulfur Burning
2, 500 ppm Emission Level
Add'l Acid By Prod. Control
T/D T/D Eff.
6
34
6
-
6
6
6
6
6
5
6
-
3
3
.0
6
.0
Not Applicable
9.8
.2
.2
.2
.2
Information Not
.2
.8
.4
No
Value
15
. 2 (sol'n)
.2 2.8
ppm
500
500
500
125
125
125
125
125
Class 1. 2 Sulfur Burning
4. 000 ppm Emission Level
Capital Add'l Acid By Prod.
Cost T/D T/D
1
513,
482,
482,
520,
470,
490,
540,
450,
000 9.1
000 38
000 9. 1
000 --- 15.6
000 10
000 10
000 10
000 10
Control
Eff.
ppm
500
500
500
200
200
200
200
200
Class 1.4 Smelter Gas
3, 200 ppm Emission Level
Capital Add'l Acid By Prod. Control Capital
Cost T/D T/D Eff. Cost
1
513,
482,
482,
590,
510,
530,
585,
465,
000
000
000
7.0
000
000 7.0
000 7.0
000 7.0
000 7.0
ppm j|
No t Applic able
Not Applic able
Not Applicable
500 620,000
160 575,000
160 600,000
160 640,600
160 535,000
Available
250
500
-0-
125
125
125
700,
670,
395,
265,
550,
565,
000 9.5
000 9
000 10.4
No
000 --- Value
25
000 5.0 (sol'n)
000 5.0 4.4
250
500
-0-
200
200
200
700.
670,
395,
285,
620,
690,
000
000
000
000
000 6. 5
000 6. 5
No
Value 160 310,000
30
(sol'n) 160 700,000
5.5 160 770,000
(1) With Maximum Additional Sulfur Firing
(2) Without Additional Sulfur Firing
-------
TABLE 14
ESTIMATED CAPITAL INVESTMENT REQUIREMENTS
FOR
SELECTED SCL EMISSION CONTROL PROCESSES
AT
VARIOUS PLANT CAPACITIES
Process
1. 1. 1
1.2.2/1.2
2.2. 6/1.2
2.2. 14/1.2
2.2.29/1.2
2. 3.3/1.2
Initial Control
Emission Effectiveness
Level ppm 50 ST/D 250 ST/D 750 ST/D 1500 ST/D
Dual Absorption
(new plant, sulfur burning) 500
Add-On Dual Absorption 4, 000 500
MgO Absorption 4, 000 200
Methylamine SOQ-HSO0 Abs. 4,000 200
o o
Resin Absorption 4, 000 -0-
Lime Absorption 4,000 200
$ $1,300,000 $2,500,000 $3,700,000
260,000 482,000 920,000 1,450,000
285,000 510,000 780,000 1,045,000
270,000 465,000 765,000 1,080,000
195,000 442,000 870,000 1,312,000
180,000 285,000 425,000 570,000
-------
TABLE 15
APPROXIMATE CAPITAL INVESTMENT REQUIREMENTS
FOR VARIOUS
ACID MIST CONTROL SYSTEMS
New Plants
50 T/D
Control System 3, 750 ACFM
3. 1.1
3. 1.2
3. 1.3
3.2. 1
3.3. 1
Dual Mesh Pads $ 10,000
Tubular Fibre Type 55, 000
Panel Fibre Type 14, 000
Electrostatic 60, 000
Venturi Scrubber
250 T/D 750 T/D 1, 500 T/D
18. 700 ACFM 56, 000 ACFM 1 12, 000 ACFM
$ 20.
70,
23,
85,
70,
000 $ 28,000 $ 38,000
000 105,000 170,000
000 55,000 95,000
000 105,000 200,000
000
Existing Plants
50 T/D 250 T/D 750 T/D
3, 750 ACFM 18, 700 ACFM 56, 000 ACFM
$ 13,000 $ 25,
78,000 100,
27, 000 44,
60, 000 85,
70,
000 $ 35, 000
000 150,000
000 105, 000
000 105,000
000
1,500 T/D
112,000 ACFM
$ 48.000
240, 000
170, 000
200,000
NOTE:
Size and cost depends upon tail gas flow rate.
Costs are given for class 1. 2 sulfur burning plants.
Adjustments proportional to gas flow must be made for various wet gas plants.
See Part III.
-------
I Capital Investment vs. H,SO Plant Capacity
'4 for
Various Control Systems
Applied to
Class 1. 2 Acid Plants
NOMINAL PLANT CAPACITY, SHORT TONS/DAY
-------
CONSULTING DIVISION
D. CONTROL COST
Control cost, as used in this report, may be defined as the
incremental production cost per ton of acid produced caused by
application of a control system to a plant or unit to achieve a
selected control effectiveness. As discussed previously, it may
be possible to achieve various levels of control effectiveness
with a selected process, and thus have different control costs
for the same system.
Control costs calculated for various "feasible" processes as
applied to different classes of plants and at different control
effectiveness levels are given in Table 16. Details of the
control costs are shown in the appendix.
In the calculation of control cost the following basic assump-
tions have been made. Where additional acid is produced it
is assumed that this is desirable and that it can be marketed
at the same prevailing price as all other acid. Where a by-
product is made, the cost of selling of the by-product has not
been accounted for, but must be deducted from the selling
price.
Control cost is calculated by determining the cost per ton of
acid produced on an annual basis from a class of plant with a
control system, then deducting the cost per ton of acid
produced on an annual basis by the basic plant from it.
V - 11
-------
CONSULTING DIVISION
The control costs for mist control only are small for most systems, as
can be seen from Table 16(c). The principal cause for variation in
control cost in using these devices is not control effectiveness, inlet
concentration or type of plant, but whether the plant is new or existing.
P'or most systems there is a marked saving when the system is provided
initially over the cost of adding one later. The exceptions are 3.2.1
and 3. 3. 1 which are normally external units not incorporated with the
absorption tower in any case.
For other types of processes the causes for variation in control costs
are discussed in the subsequent paragraphs.
V - 12
-------
TABLE 16a
CONTROL COSTS FOR VARIOUS DUAL ABSORPTION PROCESSES
APPLIED TO
VARIOUS TYPES. CAPACITIES AND EFFICIENCIES OF ACID PLANTS
FOR
500 PPM SO^ CONTROL EFFECTIVENESS
Process
1.1.1 Dual Absorption
1.2.1/1.1
1.2. 1/1.2
1.2.2/1. 1
1.2.2/1.2
Initial
Emission
Level
---
5,000
4,000
5,000
4,000
(2)
Without Supplementary Production With Supplementary Production
50 T/D 250 T/D
$ $ .41
1.44
1.48
3.50 1.36
1. 39
750 T/D
$ .18
.78
.95
1,500 T/D 50 T/D 250 T/D 750 T/D 1, 500 T/D
$ . 12 $ $ $ $
2.30 .92 .59
.76 .73 .51 .48
1.2.3/1.4
3,200
2.31
(1) Compared to class 1.2 acid plant
(2) About 15%
-------
TABLE 16b
CONTROL COST FOR VARIOUS TAIL GAS RECOVERY PROCESSES
APPLIED TO
VARIOUS TYPES, CAPACITIES AND EFFICIENCIES OF ACID
PLANTS
FOR SO,,, SO_ AND MIST CONTROL
Process
2. 1. 1/1.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
1.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
3.
3.
3.
4.
4.
4.
4.
4.
4.
1/1.
6/1.
6/1.
6/1.
6/1.
6/1.
6/1.
6/1.
6/1.
6/1.
8/1.
8/1.
8/1.
14/1
14/1
14/1
28/1
28/1
28/1
29/1
29/1
3/1.
3/1.
3/1.
5/1.
5/1.
5/1.
6/1.
6/1.
6/1.
£ O
Emission Level 50 T/D
1
2
1*
2*
2*
2*
'4*
1
2
2
4
1
2
4
. 1
.2
.4
. 1
. 1
.2
. 1
.2
1
2
4
1
2
4
1
2
4
5,
4,
5,
4,
2,
2,
3,
5,
4,
2,
3,
5,
4,
3,
5,
4,
3,
5,
5,
4,
5,
4,
5,
4,
3,
5,
4,
3,
5,
4,
3,
In
000 ppm
000
000
000
500
000
200
000
000
500
200
000
000
200
000
000
200
000
000
000
000
000
000
000
200
000
000
200
000
000
200
Out
250 ppm $
200
250
200 8.61
125
100
160
250
200 8.82
125 8.70
160
250
200
160
250
200 6. 10
160
500
250
200
-0-
-0- 4.15
250
200 6.00
160
250
200
160
250
200
160
250
$ 3.
3.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
1.
1.
2.
2.
2.
2.
1.
1.
2.
2.
2.
2.
2.
3.
3.
3.
3.
T/D
13
05
57
37
36
35
70
71
51
51
92
84
73
35
98
88
58
87
87
96
50
63
33
14
48
63
52
05
50
33
76
750 T/D
$
1. 05
1. 18
1. 15
1. 03
1. 08
1. 33
1. 500 T/D
68
.80
.78
78
86
, 94
* SO2 Emission Control Only
-------
TABLE 16c
Process
3.1.1/1. 1
3. 1. 1/1.2
3. 1. 1/1.4
3. 1. 1/2.2
3. 1.2/1. 1
3. 1.2/1.2
3. 1.2/1.4
3. 1.2/2.2
3.1.2/2.4
3. 1.3/1. 1
3. 1.3/1.2
3.1.3/1.4
3. 1.3/2.2
3. 1.3/2.4
3.2. 1/1. 1
3.2. 1/1.2
3.2. 1/1.4
Existing Plants
50 T/D 250 T/D
$ . KT $ . 08
.10 .07
. 11
.33
1.25 .33
.45
. 15
.45 .13
.23
.26
1.05 .25
.33
CONTROL COST FOR VARIOUS MIST CONTROL SYSTEMS
APPLIED TO
VARIOUS TYPES OF ACID PLANTS
Non Oleum Plants Oleum Plants
New Plants Existing Plants New Plants
750 T/D 50 T/D 250 T/D 750 T/D 50 T/D 250 T/D 750 T/D 50 T/D 250 T/D 750 T/D
$ $ $ $ $ $.06$$ $ $
.02 .04
.05
.10 .06 .02 N.A.
.17 .28
.90 .22 .07 .18
. 31
.10 .10
.22 .05 .03 .02
.10 .05
.22 1.05 .25 .22 .90 .22 .19 .90 .22 .19
3.3. 1/1.2
3.3. 1/2.2
.36
.36
N.A.
N.A.
-------
CONSULTING DIVISION
Variation of Control Cost with Inlet Concentration to the Control System
For add-on dual absorption systems the control cost is lower when
applied to less efficient acid plants with high emissions of SCX. This
occurs because the control effectiveness of these systems is fixed at
about 500 ppm, so that with less efficient plants, for the same capital
investment, more of the sulfur feed can be recovered as salable
product, spreading the cost of operating the control system over a
larger tonnage of product. This is illustrated in Figure 28.
From this it is obvious that after a control system of this type is
added, it will be to the advantage of the acid plant operator to push a
plant to its maximum capability, assuming that there is a market for
the acid. This factor makes the control cost for process 1.2.2
superior to 1.2. 1, as shown by Figure 29, which shows reduction in
control cost for process 1. 2. 2 when burning additional sulfur to
supplement production rather than gaining the necessary heat for dual
absorption by reduction of steam production. The lower limit of
control cost then depends upon the overdesign factors existing in the
base plant. In some cases it may be possible to remove bottlenecks
or make minor modifications in the base plant to further increase acid
production and reduce control cost.
For tail gas scrubbing type processes, however, this does not appear
to be the case, as shown on Figure 28 for process 2. 2. 6. Here the
control cost remains constant with changes in inlet conditions. The
value of additional acid recovery almost offset by additional capital
costs. Other tail gas treating systems may give a slight advantage
when pushed, depending upon the portion of the capital cost of the
V - 13
-------
0<
CM •
<»:
Si
Is
gu
4 i ;
- ! :-
d±p
1000
2000 3000 4000 5000
INLET S02 CONCENTRATION, PPM
6000
7000
-------
COT
2X3 CVCLLS
9 1
SULFUR FIR NG
i
SUPPLEMENTARY PRODUCTION
WITH 15 % SUPPLEMENTARY PRODUCTION
WITHOUT SUPPLEMENTARY PRODUCTION
i i -I. iii
WITH, 15% SUPPLEMENTARY PRODUCTION
10
7 8 9 100 200
NOMINAL PLANT CAPACITY ST/D
9 1
-------
CONSULTING DIVISION
process represented by the SO~ recovery section. Those which have a
smaller portion of their cost in the recovery section are the ones which
may have some advantage in operating with a higher SO2 content in the
tail gas.
V - 14
-------
CONSULTING DIVISION
Variation of Control Cost with Control Effectiveness
Generally, there appears little can be gained in operating a tail gas SO
£
recovery system below its maximum capability. An add-on dual absorption
process control effectiveness can be improved slightly by making modifica-
tions to SO9 concentration, air rate, catalyst quantity and converter
^i
temperature, but the change in control cost will be minimal. There would
be very little advantage in operating a dual absorption system below its
normal capacity. As can be seen from calculations of control costs in the
appendix, the greatest portion of control cost is introduced by capital
investment and requirements for additional plant operators where
required. Very little is introduced by changes in utility requirements.
Tail gas treating systems if operated at a control effectiveness of 500
ppm rather than 200 ppm, for example, would save a little in capital
cost, and slightly reduce utility costs by reducing circulation require-
ments in the absorption system. The saving would be a matter of a few
cents per ton of acid in most cases. A possible exception may be a
process such as 2. 3. 3 which produces a waste product. In this case a
control system for a 1, 500 T/D acid plant controlling from 4, 000 ppm
to 200 ppm has a control cost of $. 94 . A system of control to 500 ppm
would have a control cost of $. 89, a reduction of less than 6%. For a
50 T/D acid plant the reduction would be from $6. 00 to about $5. 80, a
reduction of only 3%.
V - 15
-------
CONSULTING DIVISION
Variations of Control Cost with Plant Capacity
The control cost falls significantly as the size of acid plants to which a
control system is applied increases. This is true for all systems
studied. It is important, however, to note that the rate at which the
control cost decreases is not the same for all systems. This is
illustrated by Figure 30.
Systems such as resin adsorption (2. 2. 29) and lime scrubbing (2. 3. 3)
are lowest in control cost among tail gas treating systems for small
plants, but more costly relative to other systems when applied to large
plants. This is due to cost factors in these processes which increase
in direct proportion to plant capacity at a given emission level such as
resin volume and the quantity of lime consumed.
By this illustration we conclude that processes which are potentially
attractive for application to small plants may be less attractive for
large acid plants, and vice versa.
V - 16
-------
ARiHHF ••P-11V
^ KEUFFCL a ESSER CO. HADE l« U.S.A.
2X3 CYCLES
5 67891
WITH VARIOUS TAII,. GAS
M EFFECTIVENESS MINIMUM
0.1
9 1
NOMINAL PLANT CAPACITY, ST/D
-------
CONSULTING DIVISION
Control Costs for New and Existing Acid Plants
The control cost for a new dual absorption plant is lower than that for
an existing plant converted to dual absorption. Some reasons for this
were discussed previously.
For tail gas recovery systems the cost may be slightly less for an all
new installation. Differences would be increased by lack of space at
an existing unit, which could make application to an existing unit
considerably more expensive.
For mist control, however, installation in an existing unit can make
a significant difference in the control cost, as shown below; for 250
T/D plants, Classes 1.2 and 2. 2, producing no oleum:-
Control Cost Control Cost
System $/Ton for 2. 2 $/Ton for 1. 2
3.1.1 Dual Mist Pads $ . 06 $ .07
3.1.2 Tubular Type .22 .33
3.1.3 Panel Type .05 .13
V - 17
-------
CONSULTING DIVISION
Special Situations
Many factors peculiar to a plant or location can affect the control cost of
any system; however, it is not felt that there are any acid plants to which
it would be technically impossible to apply some type of control system.
There may be some, however, which would find the control cost so high
that the plant could not be operated economically, such as small plants,
congested plants, and marginal plants.
Some situations require a special evaluation, such as the following
example which is illustrated by Table 17. Assume an acid plant of four
producing units, two of which are 150 T/D class 1. 1 plants, one is a
300 T/D class 1. 2 plant and the fourth is a 600 T/D class 1. 2 plant.
To apply process 2.2.6, employing MgO scrubbing with SO0 recovery
£
would require 4 scrubber sections and one recovery section capable of
handling the combined capacity of the four acid units. This would also
add one operator. The production cost per ton of acid for this
combination is $12.68.
To apply four separate add-on dual absorption systems of type 1. 2. 1
would require 4 individual designs, but add no operators. The
production cost in this case if $12. 76, virtually the same, though for
a single unit the 1.2.1 system results in a far lower control cost than
2. 2. 6. This illustrates the possible advantage of a central recovery
system. It is also possible to install a central add-on dual absorption
in certain situations. The dual absorption would be somewhat different
from these described here, however.
V - 18
-------
CONSULTING DIVISION
Special conditions affecting a particular plant can radically affect the
control costs shown here. Some of these might be a readily available
low cost supply of a required chemical, a unique need for a by-
product that could be produced, existence of sufficient operators, and
many more. Detrimental conditions may be lack of space, unusual
construction problems, costly startup or operating costs related to
use of a process which has not been satisfactorily demonstrated,
waste material disposal problems, among others. This work has
attempted to place control costs on a comparable basis.
V - 19
-------
CONSULTING DIVISION
TABLE 17
COMPARISON OF ACID PRODUCTION COSTS
FOR
MULTI-UNIT PLANT WITH
CONTROL SYSTEMS 1. 2. 1 AND 2.2.6
NOTE: Plant consists of 4 units; 2 class 1. 1, 150 T/D each,
1 class 1. 2, 300 T/D and 1 class 1.2, 600 T/D for a
total daily production of 1, 200 T/D.
Process
Nominal Capacity
Production Rate
Conversion Rate
2.2. 6/1. 1, 1.2 (1200)
1,200 T/D
1,254 T/D
99.775 %
1.2. 1/1. 1, 1.2 (1200)
1,200 T/D
1,250 T/D
99. 5 %
Initial Investment
Book Value
$6, 215,000
3,295,000
$6,825,000
3. 905,000
Raw Material and Utilities
Sulfur
Elec. Power
Cooling Water
Process Water
Bo F. Water
Steam
Fuel Oil
MgO
Operating Expenses
Labor
Supervis ion
Maintenance (4%)
Overhead @ 70% of Above
Indirect Costs
Depreciation 10%)
Interest 7-1/2% )
Taxes and Insurance
(1-1/2%)
Annual Operating Cost
T/Y Acid Production
Production Cost/T
$3, 390,000
211,000
124,200
1, 650
28, 900
- 322,500
150,300
53, 800
237,500
63,300
247,500
384,000
576, 500
93.200
$5, 239, 350
413,300
$ 12.68
$3,390, 000
277,000
144,000
1, 650
23,700
- 260.000
190,000
63,300
273,000
368, 500
683,000
102,300
$5,256,450
412,000
$ 12.76
NOTE: Class 1. 1 Units Assumed 5,000 ppm Emission
Class 1. 2 Units Assumed 4, 000 ppm Emission
-------
CONSULTING DIVISION
Economic Comparison of Control Systems
The technically ideal control system would also be ideal from the
economic standpoint if it did not add to the cost of producing acid, but
again, such a system does not presently exist. No one of the systems
studied in this report produces the lowest control cost for all sizes and
types of acid plants under all conditions.
Add on dual absorption systems may also requ re the addition of mist
control equipment to achieve complete control if none exists on the
base plant. In this instance, the cost of mist control must be added to
the cost for SO_ control. Of the add on dual absorption systems 1.2.2
seems to offer SO control at minimum cost, especially if the base
Ct
plant is capable of additional acid capacity as a result of inclusion of
1.2.2. This is true over the entire existing capacity range for
single units.
P'or tail gas recovery processes, however, the selection is not as
clear cut. Generally, for small plants the simplest systems, 2. 3. 3
and 2. 2. 29, produce minimum control cost. For larger plants 2. 2. 6
and 2. 2. 14 appear most attractive. There is an intermediate area
where the control costs for these four above mentioned systems are
approximately equal.
Mist control systems offer several choices at approximately equal
control cost for equivalent removals. The control cost for the
simpler systems are so small that it will make little difference
which is selected.
V - 20
-------
>
3
<
-------
CONSULTING DIVISION
VI
ECONOMIC EFFECTS OF
RECOVERED SULFUR VALUE UTILIZATION
There has been considerable effort expended in developing systems for
control of atmospheric emissions from sources which emit large
quantities of SO^, particularly fossil fuel power plants and smelters.
When a significant number of these processes become operational new
sources of sulfur will appear. This sulfur may take the form of
elemental sulfur, sulfur dioxide, sulfuric acid or a sulfur containing
salt for sale (from which SO may be readily recovered, such as
MgS03).
If these sources become available they will compete with sulfur for the
sulfuric acid market. They will not compete with acid sludge, H9S or
SO from smelting operations, since these materials are already
£j
recovered waste products which must be disposed of in some manner.
The only form which the recovered sulfur may take, which is not
presently used as a raw material for sulfuric acid, is 100% SO . In
this section several methods of using SO in the H SO industry are
£ £* T:
discussed.
There has been surprisingly little interest in the recovery of SO from
either smelter gas or power plant stacks as liquid SO . If sulfuric acid
cannot be made on the spot -- and on the whole power plants do not want
to make it -- most operators would prefer to make sulfur, or if that
proves impossible, magnesium sulfite or some other easily transport-
able solid. It is probably correct to say that any recovery plant in
operation at this time produces either sulfuric acid or sulfur.
VI - 1
-------
CONSULTING DIVISION
The objections usually raised to SO are the problems of storage and
^
transport. Obviously, sulfur has great advantage here, being a non-
toxic safe solid or only half the weight of SO0, but to reduce SO9 to
£ £
sulfur uses relatively expensive reducing agents as well as heat.
Liquid SO would be lighter to transport than sulfuric acid (only about
LJ
2/3 the weight) and would not be much more difficult. Liquid ammonia
and LPG are transported in large quantities at higher pressures than
are necessary for SO0.
Liquid SO can replace a proportion of the sulfur in any sulfur burning
acid plant without significant modification. It can also be fed to a
roaster gas plant -- but if ore-roasting is the main factor this would
not be acceptable, since roaster operation would have to be reduced to
avoid excess SO0. This is probably the way any use of liquid SO0 would
L* £i
start. The two H9SO processes designed to use liquid SO described
& ~r &
here are of special interest from a pollution standpoint. The total
recycle oxygen process has virtually no effluent and the partial recycle
air process allows only 113rd of the SO? into the atmosphere compared
to a comparable sulfur burning plant. We believe, therefore, that these
represent a significant advance in reducing pollution. It now only
remains to find an acceptable SO_ recovery process. Further develop-
ment of some of those described may provide the answer.
Utilization of SO in existing plants would curtail steam production,
which might not be desirable.
It is unlikely that existing acid plants could be economically converted
to use 100% SO2.
VI - 2
-------
CONSULTING DIVISION
Partial Recycle Air Process (PRAP)
The Partial Recycle Air Process (PRAP) utilizes tonnage SO2 (100% SO2)
and air for the manufacture of 98% sulfuric acid. The main technical
advantage of the process from an air pollution standpoint is that tail gas
emission is about one third the amount from a standard sulfur burning
plant, hence the SO discharge is one third also. This is due to the fact
that two out of three moles of O? used up in a contact sulfuric plant go for
the oxidation of sulfur to sulfur dioxide, but when sulfur is available as
SO0 the only O required is to cbnvert SO to SOQ. As a result, no
2* 2i 2t o
sulfur furnace, waste heat boiler or associated equipment are required
and the drying tower is designed for one third the duty of a conventional
contact plant. The converter boiler and economizer are replaced by a
series of heat exchangers designed to reheat the converter feed gas
mixture, but otherwise the contact and acid making sections of the plant
remain unchanged.
The converter feed gas consists of 8% SO , 13% O and 79% N . A
98% conversion is achieved in four catalyst stages, and the SOQ rich
o
product gas is fed to the 98% absorption tower where the SOQ is
O
absorbed. The tower off-gas, being rich in oxygen, is split into re-
cycle and purge (stack gas) streams. The split is determined by the
amount of oxygen that has to be made up in the recycle gas. The stack
gas represents a nitrogen purge equal to the amount of nitrogen in the
feed air to the system. The recycle stream is enriched by SO and
air in order to maintain the original converter feed gas composition
and the cycle is repeated.
The stack gas, despite containing approximately 2, 000 ppm of SO ,
has about one third the quantitative SO emission of a comparable
VI - 3
-------
1.1
5 !
SO,
RECYCLE
BLOWER
\x\\\\\
DRYING
TOWER
AIR
AIR
BLOWER
COOLER
WATER
CONVERTER
ABSORPTION
TOWER
COOLER
•>TO ATMOSPHERE
PRODUCT
. ACID
LIST OF PARTS
CHEMICAL CONSTRUCTION CORPORATION
S AND CONTMCTMC DKMEDB
EARTJAL RECYCLE AJB PROCESS
FOR UTILIZATION OF
RECOVERED S02
BSUCD FO« CON5TVUCT1OH
AUTHOHUT10H MO.
0064 C
FIG. 31
-------
CONSULTING DIVISION
single absorption sulfur burning unit, or in terms of conversion efficiency
based on input and output of SO , PRAP achieves 99. 3% conversion, a
notable improvement over 98%.
This process, additionally, uses conventional sulfuric acid technology
and could be built on commercial scale without piloting.
In addition to the technical advantages cited above, the estimated capital
investment required for PRAP is 10-20% lower than for a conventional
sulfur burning plant of class 2.2. While an inability to produce steam as
a by-product may be a disadvantage in some instances, PRAP appears to
have distinct economic advantages if tonnage SO~ becomes available.
Table 18 shows the production cost for a 500 T/D PRAP plant. Compared
to a conventional sulfur burning plant of class 2. 2, the production cost
per ton of acid is reduced by $. 50, assuming a cost of $12. 50/ton for SO
VI - 4
-------
CONSULTING DIVISION
TABLE 18
ACID PRODUCTION COST FOR
PARTIAL RE CYCLE AIR PROCESS
Process P. R0 A. P.
Nominal Capacity 500 ST/D
Production Rate 500 ST/D
Conversion Rate 99. 3 %
Initial Investment $1, 400, 000
Book Value 1,400,000
Raw Material and Utilities
S as SC- $1, 360,000
Elec. Power 62, 700
Cooling Water 23, 800
Process Water 560
Operating Expenses
Labor 47,500
Supervision 21, 100
Maintenance (4%) 56, 000
Overhead @ 70% of Above 87, 200
Indirect Costs
Depreciation 10%)
Interest 7-1/2% ) ^4b, UUU
Taxes and Insurance (1-1/2%) 21, OOP
Annual Opera ting Cost $1, 924, 860
T/Y Acid Production 165, 000
Production Cost/T $ 11.65
-------
CONSULTING DIVISION
Total Recycle Oxygen Process (T. R. O. P.)
This is a "pollution free" sulfuric acid process which utilizes liquid 100%
SO and 99. 5% O as raw materials. The principal advantage of the
process being that essentially no tail gas is emitted as a result of using
O instead of air.
A level of inerts (N~ and rare gases) is maintained in the process loop
to control temperatures and act as a heat carrier. The process loop
consists of the total recycle of SO? and O enriched absorption tower off
gases back to the converter, the subsequent conversion of SO to SO ,
2t o
then the absorption of SO followed by re-enrichment and so forth.
Oxygen requirements may be met either by importing "over the fence"
or installing an air separation plant. An integrated TROP - Air
Separation Facility could utilize a steam driven air compressor with
56% of the energy being supplied by the waste heat generated by the
SO0 to SOq reaction.
ci O
The battery limits TROP unit is very simple and basically consists of
the following items; as depicted in Figure 32:-
two-stage converter
converter waste-heat boiler
heat exchanger
absorption tower
acid cooling system
acid pump tank and pump
recycle blower
The economics of a 500 ST/D H^SO production facility consisting of
a TROP unit and an 82 ST/D Air Separation plant yielded an estimated
VI - 5
-------
11
I:
25
u
Is
I-
CL
LIQUID S02
AIR
OXYGEN
BOILER I
BOILER FEED
WATER
WATER
PURGE
t
CONVERTER
EXCHANGER
ABSORPTION
TOWER
RECYCLE
BLOWER
COOLER
STEAM
PRODUCT
ACID
usror wum
CHEMICAL CONSTRUCTION CORPORATION
COMCULTTNC. DCSKM1NC AND COHmACTmC CMCtNEOS
TOTAL RECYCLE_OXYGEN PROCESS
FOR UTILIZATION OF
RECOVERED 502
BSUED fOU CONSTRUCTION
AimtOKtZATION HO.
0064C
FIG.32
-------
CONSULTING DIVISION
capital cost of $2, 130, 000 and assuming a raw material cost of $12. 5/ton
SO2 the cost of producing H SO is estimated at $12. 75/ton, as shown in
Table 19.
The T. R. O. P. unit requires a small purge stream in order to remove
inerts equivalent to the impurities brought in with the oxygen. For a 500
STD plant the purge is approximately 7 SCFM of 91. 5% N~ and rare gases,
7. 5% O and 1% SO ; i. e. 0. 07 SCFM SO is emitted to the atmosphere or
may be reclaimed by any appropriate means. It is worthwhile to compare
this purge with the tail gas of a modern 500 ST/D sulfur burning 10% SO
^
dual absorption plant, where the tail gas is approximately 21, 600 SCFM
containing 500 ppm SO0, the SO0 emission in this latter case is 10. 8
£ £
SCFM or approximately 154 times the amount of SO in the T.R.O.P.
purge stream. The overall T.R.O.P. unit SO efficiency is 99. 997%.
^
This process, as in the case for P.R.A.P., uses conventional sulfuric
acid technology and could be built on commercial scale without piloting.
VI - 6
-------
CONSULTING DIVISION
TABLE 19
ACID PRODUCTION COST
FOR
TOTAL RECYCLE OXYGEN PROCESS
Process
Nominal Capacity
Production Rate
Conversion Rate
T. R.O.P.
500 ST/D
500 ST/D
Initial Investment
Book Value
$2, 130,000
2, 130,000
Raw Material and Utilities
S as SO2
Elec. Power
Cooling Water
Process Water
B.F. Water
Steam
Operating Expenses
Labor
Supervision
Maintenance (4%)
Overhead @ 70% of Above
Indirect Costs
Depreciation 10%)
Interest 7-1/2% )
Taxes and Insurance (1-1/2%)
Annual Operating Cost
T/Y Acid Production
Production Cost/T
$1, 350,000
45,400
26,200
670
2,370
14.050
47,500
21, 100
85,000
107,500
373,000
31. 930
$2, 104,700
165,000
$ 12.75
-------
-------
CONSULTING DIVISION
VII
RECOMMENDATIONS
A. TECHNOLOGY LIMITATIONS
Applications
It is not likely that there is any contact acid plant in the U.S. to
which a satisfactory emission control system could not be applied.
It is doubtful, however, that all plants could be operated
economically with control systems, and such decisions would
necessarily have to be made on an individual basis. If some
plants were forced to close because the cost of control was too
high, older, smaller plants with restricted choice as to possible
control methods would probably be most affected. Timing is also
important. Certainly, the next few years will see improvements
in effectiveness and cost as new systems are developed which may
be used to advantage by marginal plants.
To the advantage of older, less efficient plants, a number of
control methods that are presently available or potentially
feasible are less costly to apply to such units.
Control Effectiveness
A control effectiveness of 2, 000 ppm (overall) is not too difficult
to reach with minor modifications to plant operation and minimum
capital expenditure. It is very likely, however, that production
will be somewhat curtailed and production costs per ton of acid
would increase as a result of such changes.
VII - 1
-------
CONSULTING DIVISION
Presently available technology will permit reducing emissions to less than
500 ppm SO0 via the dual absorption route for those plants which can
^
accommodate the necessary additional equipment. For control effective-
ness levels of 100 or 200 ppm, however, little is available which is
commercially proven. As control effectiveness becomes greater, the
number of potential choices and their degree of development decreases
rapidly. These are the areas where further development efforts need to
be concentrated.
The effectiveness of various systems will depend to a great extent upon
how they are operated, though limitations do exist. Dual absorption
processes are limited by operating plant conditions and SO0-SOo
& o
equilibrium at these conditions, which makes 500 ppm a practical level,
although 200-300 ppm is possible with careful operation.
Tail gas recovery systems will depend upon the inlet S(X concentration
in many cases to determine effectiveness. Chemico has been able to
achieve 95% removal in a venturi scrubber on a continuous basis from a
power plant stack with inlet concentrations of about 1, 500 ppm; higher
efficiencies may be feasible. Other devices such as packed towers can
be equally effective. With 95% as the removal efficiency, to reach 500
ppm effectiveness, the inlet SO concentration may be as high as 10, 000
&
ppm, but a regulation requiring 100 ppm control effectiveness will limit
inlet concentration to 2, 000 ppm. Increased absorption efficiency or
multiple absorption stages may improve this.
Tail gas recovery systems which utilize resin adsorption or molecular
sieves reportedly can achieve a control effectiveness of near zero.
They have yet to be demonstrated on a pilot or commercial scale,
however.
VII - 2
-------
CONSULTING DIVISION
Acid mist control systems which are capable of mist control well below
3 mg/SCF even for sub-micron mist from oleum plants are in commercial
operation. Regulations governing mist concentrations at ground level vary
widely, and suitability of systems should be determined on an individual
basis. In some areas 3 mg/SCF with good dispersion may be satisfactory.
In others it is not.
Oleum Plants and Mist Control
Oleum plants probably present the most acid mist control problems
since they emit more and finer mist than 98% acid plants. They will
probably be limited to a system capable of controlling SO9, SO and
£ O
mist, or a combination of dual absorption and one of the most effective
mist control systems, as 3. 1. 2 or 3. 2. 1.
Space Limitations
Generally, wet gas acid plants will tend to be more congested than sulfur
plants, and older plants more congested than new plants. In the first
place, wet gas plants are more complex; also, they are often a
secondary facility, supporting refinery operations or controlling
emission or disposal problems themselves, and as such may be
squeezed in wherever space could be found.
Older plants have been modified by the owners in various ways and
other facilities have been built nearby to occupy any extra space
available. These factors will all contribute to the difficulty of
fitting in a control system.
VII - 3
-------
CONSULTING DIVISION
Process Development
It should be stressed that many of the systems discussed, particularly
for recovery of SCX, SO,, and mist from tail gases, are not fully
developed. For the purposes of this study the control costs were
developed on the assumption that the control systems as described in
the report will perform as expected. Further development may prove
the systems better or worse, and more or less costly than the figures
given on the subsequent pages.
VII - 4
-------
Kifi0nuca£
CONSULTING DIVISION
Class 1. 1 Acid Plants
Based on the calculations in Parts IV and V, a class 1. 1 acid plant can
control to 500 ppm with the following systems and at the following control
costs for a 250 T/D unit:
Process Control Cost $/Ton H^SO
& ~r
1.2.1 $1.44
1.2.2 $ . 92
2.1.1 $3.13
2.2.6 $2.71
2.2.8 $2.84
2.2.14 $1.98
2.2.22 Unknown
2.2.28 $2.91
2.2.29 $1.50
2.3.3 $2.33
2.4.5 $2.63
2.4.6 $3.50
For control to 100 ppm, at normal emission levels, shown in Part III:-
Process Control Cost, $/Ton of H SO
u ~t
2.2.29 $1.50
A combination of 1. 2. 1 or 1. 2. 2 with any of the 2. x. x series could also
achieve this result. This combination would be very expensive and not
a likely commercial venture.
From the above it becomes evident that there is very little difference in
control cost to reach effectiveness levels of 500 ppm vs. 100 ppm.
VII - 5
-------
CONSULTING DIVISION
Class 1. 2 Acid Plants
The following systems can be expected to achieve a 500 ppm control
effectiveness with class 1. 2 acid plants at the control costs listed for
250 T/D plants:-
Process Control Cost, $/Ton of H SO
^
1.2.1 $1.48
1. 2. 2 $ . 73 to $1. 39
2.1.1 $3.05
2.2.6 $2.51
2.2.8 $2.73
2. 2. 14 $1. 88
2.2.22 Unknown
2.2.28 $2.96
2.2.29 $1.63
2.3.3 $2.14
2.4.5 $2.52
2.4.6 $3.33
For control to 100 ppm at normal emission levels shown in Part III,
the following would be applicable. Depending upon present emission
levels, it may also be necessary to also make adjustments as described
for 1. 3.4. The cost for these adjustments should be minor; and
additive to the following: -
Process Control Cost, $/TonH^SO,
^ 4
2.1.1 $3.05
2.2.6 $2.51
2.2.8 $2.73
2.2.14 $1.88
2.2.29 $1.63
2.3.3 $2.15
2.4.5 $2.52
2.4.6 $3.33
VII - 6
-------
CONSULTING DIVISION
Class 1. 3 and 1.4 Acid Plants
For control to 500 ppm the following systems may be expected to perform
satisfactorily with wet gas plants, although control cost will vary widely
with the raw material used. Control costs are generally somewhat higher
than for classes 1. 1 and 1. 2, but the relative cost positions of the various
systems should be about the same. Those given as examples are for
smelter or roaster gas plants of class 1.4.
This type was selected because their tail gas flow is between that of H?S
plants and Copper Converter gas plants. The effect of inlet concentration
and flow rate on control cost and capital cost is discussed in Part V.
The relative flow rates for various types of wet gas plants are given in
Part IV.
Process Control Cost, $/Ton of H SO
£ ~r
1.2.3 $2.31
2.1.1 *
2.2.6 $2.92
2.2.8 $2.87
2.2.14 $2.67
2.2.22 *
2.2.28 *
2.2.29 *
2.3.3 $2.48
2.4.5 $2.95
2.4.6 $3.70
For control to 100 ppm the following systems could be applied, together
with some of the process modifications outlined in 1. 3. 4 for class 1. 3
or 1. 4 plants :-
* Not Calculated
VII - 7
-------
CONSULTING DIVISION
Process Control Cost. $/Ton of H^SO
£*
2. 1. 1 *
2.2.6 $2.92
2.2.8 $2.87
2.2.14 $2.67
2.2.29 *
2.3.3 $2.48
2.4.5 $2.95
2.4.6 $3.70
For class 1. 3 plants with high initial emission levels process 2. 2. 29
may be the only suitable process, or a combination of 1. 2. 3 with one
of the above systems. Modifications suggested in 1. 3. 4 would be of
little help because of the magnitude of adjustments required in such a
case. Systems of the 2.x.x group may also be applicable with
multiple absorption stages.
Not Calculated
VII - 8
-------
CONSULTING DIVISION
B. DEVELOPMENT PROGRAMS
It is desirable to reduce some of the limitations of existing systems,
to make processes in the development stage more feasible, to
improve the capabilities of processes both in number of applications
and in control effectiveness. We have, in preparing this report,
surveyed many potential processes which may be applicable to
sulfuric acid plants. Many of these processes appear to have
common problems whose solution will improve their usefulness.
As NAPCA is interested in commercialization of effective
control systems, we have suggested several areas where new or
continued programs can help in development of as many potential
systems as possible which may be particularly applicable to
sulfuric acid plants. Development of two systems which, if
developed, seem to have the characteristics which would make
them attractive for acid plant emission control is also
recommended. These programs are listed below in a suggested
order of priority, and are further described on subsequent pages.
1. Resin or Molecular Sieve Adsorbents.
2. Oxidation Inhibitors.
3. Plume Dispersion for Scrubbed Stack Gases.
4. Development of Process 2.3. 1.
5. Development of Process 1. 3. 2.
6. Chamber Acid Plant Emission Control.
VII - 9
-------
CONSULTING DIVISION
Resin or Molecular Sieve Adsorbents
This is a relatively untouched area until recently for pollution control. For
sulfuric acid plants where tail gas is clean and the gas flows and SO0 con-
£
centrations are relatively low this type of system could prove economical,
simple, compact as well as very effective for almost all types of plants.
As this appears to offer the ultimate in SO control, its effectiveness
£
makes it the first for consideration.
Desirable characteristics of these materials include:-
High SO9 loading at partial pressures and temperatures
of SO normally encountered (. 001 to . 020 atm. )
£1
Selectivity for SO high with respect to HO
LA £
Long life (over 2 years, preferably)
Stable, unaffected by SOq or H0SO
o Li 4
Low pressure drop
Regenerates at low temperature
If a material can handle SO9 and SO- equally well, this is advantageous,
^
-------
CONSULTING DIVISION
these questions would be desirable. For some applications selectivity
with respect to CO, CO9 and nitrogen oxides may also be important.
£i
After determination of design characteristics and laboratory testing with
a synthesized tail gas, a pilot unit prototype would be required to
determine regeneration cycles and material life under actual conditions
at a sulfuric acid plant using a portion of the tail gas stream.
VII - 11
-------
CONSULTING DIVISION
Oxidation Inhibitors
Many of the tail gas treating systems for SO control utilize sulfite and
^
bisulfite salts solutions as a scrubbing medium. In many of these
systems there is a tendency for oxidation to form sulfates which are not
readily regenerable. For these processes in which a minimum of
sulfate formation is desirable, introduction of an oxidation inhibitor may
be effective. The formation of sulfate when treating H0SO plant tail
^ 4
gases is more serious than with other stack gases due to the presence of
10 to 12% oxygen in the acid plant tail gas stream. Development of an
effective inhibitor can be an important step in reducing the control cost
for several systems presently being tested, and is suggested as a second
priority. This development could be done before or in parallel with
testing of prototype systems. Prior development, however, may show
that in some one system oxidation may be easier to control than in
others. This would serve as a guide in selecting systems for prototype
testing.
The use of oxidation inhibitors to prevent oxidation of sulfite and bisulfite
salts would apply to process 2. 1. 1, 2. 2. 6, 2. 2. 8, 2. 2. 14, 2. 4. 5 and
2.4. 6. The use of an oxidation inhibitor would be important for these
processes if oxidation is excessive. The potential for oxidation is
present with the oxygen content of the tail gas being about 10%. O
£
would dissolve in the SO9 absorbing solutions.
£j
Several oxidation inhibitors have been reported in the literature;
V, A ' (1)(2) • V, 1<3>(4> ' 1<5> 1 ' <6> *
hydroquinone, p-ammophenol, qumol, glycme, etc. , whi
were effective under bench scale conditions. In addition, there are
(Footnotes - See next page)
VII - 12
-------
CONSULTING DIVISION
/n\ /o\
oxidation retardants such as stannous chloride and mannitol which
may also be applicable.
Going through the processes one by one; process 2. 1. 1 requires an
inhibitor to prevent oxidation of sodium sulfite to sulfate. Process
2.2.6 requires that oxidation of magnesium sulfite to sulfate should not
be excessive. Similarly, potassium sulfite-bisulfite, ammonium
sulfite-bisulfite and methyl ammonium sulfite-bisulfite absorbing
solutions should not oxidize inordinately. For process 2. 4. 6 calcium
sulfite oxidation should be minimized.
Besides direct oxidation there are substances which promote oxidation.
Examples of these are ferrous and copper sulfates, and sodium nitrite.
Small amounts of copper and iron can dissolve into the absorption
system from the absorbants used as well as from materials of
(1) (3) (5) Millar, J.W.
(6) (7) (8) A Comprehensive Treatise on Inorganic and
Theoretical Chemistry - Longmans Green & Co.
1922, 1937 - Wiley 1963, 1967
(2) Johnstone, H. F. , Read, H.J. , Blankmeyer, A.C.
"Recovery of Sulfur Dioxide from Waste Gases"
I. &E. Chem. - Vol 30. No. 1 - Jan. , 1938
(4) Chertkov, B.A.
Ldation of C;
m Flue Gasi
Zhur Priklad Khim. -33, 1708-1714(1960)
"Oxidation of CaSO in the Process of Scrubbing SO,
From Flue Gases"
VII - 13
-------
CONSULTING DIVISION
construction. In addition, particulate matter such as slurry solids can
act as catalysts. The pH of the absorbing solution can also accelerate
oxidation, where, for instance, under acid conditions either oxygen
becomes more reactive or certain oxidation catalysts such as FeSO
become more soluble. There are also reagents such as manganous
hydroxide, which can promote oxidation in alkaline solutions.
Solution to this problem of oxidation would, therefore, require piloting
the absorption stages and other parts of the processes where sulfite
and bisulfite salts in the liquid phase are heated above ambient
temperatures. Piloting should be done under steady-state conditions
with actual tail gases, and with reagents and materials of construction
that would be used in full-sized systems after some laboratory screening
work where conditions can be varied.
VII - 14
-------
CONSULTING DIVISION
Plume Dispersion for Scrubbed Stack Gases
As brought our earlier, liquid phase absorption of SO0 cools and saturates
£
the tail gases. Two suggested methods for maintaining effective stack
heights and preventing any rain -out of condensate are direct heating of
the cleaned gases or partial heating plus increasing the velocity of the
exiting gas. Asa guide in determining the effectiveness of this type of
process and others as well, it is important to analyze the effects of the
many factors that determine the relationship between stack emission and
ground level concentration for both SO_ and acid mist. Since acid plant tail
£A
gases are relatively cool compared with many others, this is particularly
important for acid plants. Such a study would also be valuable in helping
to define emission standards for other types of systems and other
pollutants, and is suggested as a third priority.
Mathematical studies should be made relating the many variables of plume
dispersion with ground level concentrations of SO . This would show the
&
effectiveness of increasing gas velocity and temperature to significantly
lower ground level concentrations.
The first part of the study should determine which of the many dispersion
formulas would be most suitable for scrubbed tail gas emissions. At
least two dissimilar formulas should be selected.
A second important parameter is the rate of SO,., emission (i. e. , Ibs. /mm. )
in the scrubbed gas. This is determined by the plant size, or CFM of
exiting gas, and the SO_ concentration.
VII - 15
-------
CONSULTING DIVISION
Another important set of variables are the cleaned gas velocities and
densities which determine the rise of the plume above the stack, which
in turn determines the effective stack heights. Gas velocities and
densities (or temperatures) should include values before and after heating
and increasing the velocity of the cleaned gas. Ambient air temperature
can be set at a typical summertime reading.
In addition to the intrinsic properties of the cleaned gases, geographic
and geometric factors should also be taken into account. These include
physical stack heights and horizontal distances downwind from the source
to a point on the ground.
The more difficult variables to establish are meteorological and the
topographic, the latter of which adds to the complexity of plume
diffusion. The stability of the atmosphere is expressed in certain
dispersion formulas as an exponent of the distance downwind of the
source. Three atmospheric stability factors have been shown but only
two have been chosen for these calculations, most stable (inversion) and
average. The elements of terrain such as buildings, mountains, shore-
line, trees and valleys, which cause turbulence or channeling of plumes,
are too variate for any numbers to be established. Acid plants, however,
are usually in non-urban areas so the above turbulence factors may not
be critical except for plant locations in valley areas. In this case
maximum atmospheric stability would probably be indicative of plume
dispersion.
Wind velocity, another important meteorological variable, is inversely
proportional to contaminant concentrations. A suitable range of
velocities should be selected.
VII - 16
-------
CONSULTING DIVISION
From the above the number of variables for each category is tentatively
set as follows for the calculation of groundlevel SO concentrations:
Number
Dispersion Formulas 2
Plant Sizes, T/D: 100, 500, 1,500 3
SO Concentrations, Scrubbed Gas:
50, 100, 200, 500 ppm 4
Scrubbed Gas Velocities: one typical,
two increased 3
Gas Densities or Temperatures:
one at typical saturation,
two above saturation (heating gas) 3
Ambient Air Density - at one temperature 1
Atmospheric Stability - Exponent for more
stable and average conditions 2
Stack Heights: 20, 50, 100, 250 Ft. 4
Distances from Source:
0. 1, 0. 5, 1. 0, 2. 0 mi. 4
Wind Velocities: Low and Moderate 2
Total SO Groundlevel Values 13, 824
LJ
After completion of the mathematical phase it may be desirable to
measure each of the factors at various locations and condtions to
check the validity of the theoretical calculations.
VII - 17
-------
CONSULTING DIVISION
Development of Process 2. 3. 1
This process was chosen because of its similarity to process 2. 3. 3 which
is already potentially attractive for SO control of sulfuric acid plant tail
gases. Process 2. 3. 3 is simple, effective and well developed; process
2. 3. 1 is undeveloped, but uses CaCOQ in place of CaO. CaCO is much
o o
less expensive than CaO, and with successful development 2. 3. 1 could be
a useful control system, approaching dual absorption in control cost
while having a greater control effectiveness.
The objective is to increase SO0 absorption and alkali consumption
£i
efficiency of systems utilizing limestone or dolomite slurries for the
absorption of SO . This is to be achieved by adding an agent which will
£>
increase the solubilities of the calcium and magnesium carbonates in
these minerals, providing greater concentration of dissolved reactant.
In addition, many limestomes and dolomites which have been classified
as ineffective for the absorption of SO9 may then be usable.
Lt
Fair to middling absorption and alkali consumption efficiencies are
effected by many limestones and dolomites due to low solubility of the
calcium and magnesium carbonates (in water). The presence of
impurities in these minerals may inhibit the reaction of a substantial
portion of the carbonate with sulfurous acid.
Acetic acid reacts with carbonate as follows:-
2HC2H3°2 + CaC°3 > Ca(C2H3°2)2 + H2°
The acetate ionizes providing a greater reactant concentration:-
Ca(C2H3°2)2 » Ca++ + 2C2H3°2
Ca++ + SQ3 = >, CaSO3
VII - 18
-------
CONSULTING DIVISION
Therefore, when SO is absorbed the acetic acid is regenerated:-
&
Ca (C2H3°2)2 + H2S°3 > 2HC2H3°2 +
The free acid formed in the absorption stage would then dissolve carbonate
mineral in its immediate presence. The mineral would be finely ground
and completely dispersed throughout the slurry. Maximum acetic acid
concentrations developed during absorption would be below the point at
which there would be significant vaporization into the flue.
The reagent costs for the Acetic Acid-Limestone process are estimated
to be about one-half of that for the Lime Process (2. 2. 3). For each ton
of lime, 1. 9 tons of limestone wcu Id be required plus 0. 0123 tons of
acetic acid. SO absorption efficiency would probably be lower for
^
limestone, 90% instead of 95%, but alkali consumption efficiency may
be about the same (90%).
VII - 19
-------
CONSULTING DIVISION
Development of Process 1. 3. 2
Introduction of ozone to promote the oxidation of SO to SO is very
different from most of the systems surveyed. Chemico has done some
testing in this area, and results are sufficiently encouraging to
recommend additional study. The system is very simple and adaptable
to all acid plants. Control cost could be as low as $. 07 for a 250 T/D
plant at an effectiveness of 500 ppm of SO .
It is suggested that bench scale and test work at an acid plant site be
done with regard to the oxidation of the SO9 with ozone remaining after
£i
the catalytic oxidation step. Ozone would enter the system between the
economizer and the 98% absorption tower to oxidize the SO0 in the SO -
£ o
SO -O9-N9 gas mixture. The SO0 concentration in the tail gas would
<£ £* & &
then be reduced to an amount at which emissions to the outer air would
no longer be a problem.
The objective would be to have very efficient oxidation, that is one mole
of ozone oxidizing several moles of SO9. Oxone may react most
rapidly with the SO- to form an unstable compound which, upon
decomposing, could activate many times its number of SO9 and OQ
<£ Ct
molecules. Another possibility is that ozone would decompose with
such vigor that it could activate SO9 and O in its immediate vicinity.
A relatively small ozone generator would be required with the ozone
containing gas entering the system evenly dispersed across its
entrance point.
The estimated cost of a system recovering 6.8 T/D of 98% acid from
a 250 T/D acid plant is listed in Table 19. The 6. 8 T/D of acid is
equivalent to 90% removal of the 2, 500 ppm of SO in the tail gas.
£t
VII - 20
-------
CONSULTING DIVISION
From the above estimate ozone oxidation efficiency would have to be
about 30 or better ($12/ton fUSO. or less) for the process to be
economical. This represmts a control cost of $.47.
VII - 21
-------
TABLE 19
ESTIMATED OPERATING COST OF OZONE SYSTEM
Ozone Efficiency
SO,, Oxidized Mole O0/Mole
^ o
1
5
20
50
200
Capital, Interest,
Maintenance, etc. ,
$/Day
$57.
20.
12.
8.
6.
00
20
00
10
15
Power At
$0. 01/KWhr and
3. 75 KWhr/ lb/03
$229.
45.
11.
4.
1.
00
50
40
55
14
Liquid Oxygen
At $10/Ton
$1, 920.
383.
96.
38.
9.
00
00
00
00
60
Total
$2,206.
448.
1.19.
50.
16.
$/Ton H2SO4
Recovered
00
70
40
65
89
$326.
66.
17.
7.
2.
00
30
70
48
49
-------
CONSULTING DIVISION
Chamber Acid Plant Emission Control
This recommendation is made to cover the one area of the sulfuric acid
industry which cannot achieve effective control with any of the processes
discussed in Part IV. Chamber plants are small, but could present local
problems which would require a different approach than contact plants,
since nitrogen oxides which are emitted are very difficult to absorb.
Should it be desirable to develop a control system suitable for chamber
plants the following course is suggested.
A first step should be a review of the literature search which is Volume
II of this report to determine the more promising absorbents or
adsorbents for NO . A simple system would be desirable based on tests
X
made with inexpensive media to determine which ones can efficiently
entrain NO and NO . The system can be an absorbing solution, a slurry,
£i
wet or dry solids. NOX and SO would probably require removal in two
Li
stages. A waste product which could be disposed of would be satisfactory,
since quantities may be expected to be small.
A relatively inexpensive system for NOX control might also find
applications in other fields.
VII - 22
-------
FIGURE 0
40
50
60 70
TEMPERATURE °C
80
90
100
-------
FIGURE D
it.
30
50 60 70
TEMPERATURE °C
80
90
100
-------
FIGURE C
40
50
60 70
TEMPERATURE °C
60
90
100
-------
\ /'
10 rHVcH BH1132I
7 X 1O INCHES «ADt III U.».«.
KEUFFEL ft ESSER CO.
SO,-OLEUM EQUILIBRIUM
45
-------
SULFURIC ACID PRODUCTION COSTS
Plant
Class Process
1.0 Chamber, Sulfur Burning
1. 1 3-Stage Contact, Sulfur Burning
I. 1 3-Stage Contact, Sulfur Burning
1.2 4-Stage Contact, Sulfur Burning
1.2 4-Stage Contact, Sulfur Burning
1.2 4-Stage Contact, Sulfur Burning
1. 3 3-Stage Contact, Smelter Gas
1.4 4-Stage Contact, Smelter Gas
1.4 4-Stage Contact, Smelter Gas
1.4 4-Stage Contact, Smelter Gas
Products
78% Acid
<99% Acid
Acid + Oleum
< 99% Acid
Acid + Oleum
< 99% Acid
<99% Acid
< 99% Acid
Acid + Oleum
< 99% Acid
Con ver s ion
Rate
96. 5%
95
95
96
96
97. 5
95. 8
96.8
96.8
98.2
Estimated Production Cost - Dollars Per Short Ton of Acid (As 100% H2SO4)
50 T/D 113 T/D 250 T/D
$18.50 $13.74
17.85 $11.17
11.26
22.30 13.43
13. 74
22.18 13.28
16.79 5.20
8.80
9. 12
340 T/D 750 T/D 1. 500 T/D
$ 9. 84
11.25 $10.38
11.08 10.23
2.95
5.01 3.74
$ 7.46
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CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 1. 1. 1 - Dual Absorption (New Plant)
Description:
Similar to conventional contact plant up to conversion step.
Absorption of SO takes place after 2 or 3 conversion stages;
SO9 gas is reheated and returned to the converter for additional
conversion and acid recovery in a second absorber. There are
several variations depending upon conversion requirements and
plant steam system.
Recovers:
SO in the form of product H SO. for sale.
Status:
In commercial operation.
Licensor:
Bayer
Applications:
Reduced SO emission from new sulfur burning contact plants.
L*
Control Level Obtainable:
To 500 ppm for SO9; no mist control
^
Expected Relative Cost:
Capital Cost Average-High
Operating Cost Low
Reliability:
Same as modern contact plant.
Estimated Overall Worth:
Good.
Feasible. Shows enough potential to warrant further evaluation.
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CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 1.2.1 - Add-On Dual Absorption using Converter Heat.
Description:
Stack gas is heated utilizing a part of the heat of reaction from
the converter. This gas is blown through a new secondary
converter and absorber to produce additional acid product.
Recovers:
SO0 in the form of product H SO. for sale.
^ ^4
Status:
Current technology, being offered commercially.
Licensor:
Chemico
Applications:
Reduce SO emission from most sulfur burning contact plants.
^
Control Level Obtainable:
500 ppm for SO,,; no mist control.
^
Expected Relative Cost:
Capital Cost Average
Operating Cost Low
Reliability:
Good. Equal to existing plant
Estimated Overall Worth:
Good.
Feasible where space is available. Shows enough potential to
warrant further evaluation.
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CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 1.2.2 - Add-On Dual Absorption using Furnace Heat
Description:
Stack gas is heated with hot furnace gas obtained by burning
additional sulfur in the sulfur furnace, which bypasses the
boiler system and first converter. The additional SO? +
stack gas is converted to SO., in a new two stage secondary
converter, and passed through a secondary absorber to
provide additional acid product.
Recovers:
SO in the form of product H SO for sale.
£* £* ~I
Status:
Current technology being offered commercially.
Patents:
Applied for.
Licensor:
Chemico
Applications:
Reduce SO emission from most sulfur burning contact plants to <.500 ppm.
c*
Expected Relative Cost:
Capital Cost Average
Operating Cost Low
Reliability:
Good - equal to existing plant.
Estimated Overall Worth:
Good.
Feasible where space is available. Additional production
limited by furnace and blower capacity of existing plant.
Shows enough potential to warrant further evaluation.
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CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 1.2.3 - Add-On Dual Absorption using Outside Heat Source
Description:
Stack gas is heated in a fired heater and blown through a new
secondary converter and absorber to produce additional
product acid.
Recovers:
SO in the form of product H9SO for sale.
ft Z 4
Status:
Current technology.
Applications:
Reduce SO0 emission from wet gas contact plants.
L*
Control Level Obtainable:
500 ppm for SO ; no mist control.
^
Expected Relative Cost:
Capital Cost Average
Opera ting Cost Average
Reliability:
Good - equal to existing plant.
Estimated Overall Worth:
Fair.
May be feasible for some wet gas plants.
Shows enough potential to warrant further evaluation.
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CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 1. 3. 1 - Ultraviolet Oxidation of SO
Description:
SO gas is passed into a chamber irradiated with ultraviolet at
1, ff6oA. The SO is oxidized to SO and the latter is
recovered in an additional 98% absorber producing acid.
Recovers:
SOQ in the form of SO for absorption to H SO .
Z o £ 4
Status:
Experimental
Applications:
Reduction of SO9 emission for most contact plants.
£*
Control Level Obtainable:
About 500 ppm for SO ; no mist control.
£i
Expected Relative Cost:
Capital Cost Average
Operating Cost High Power Cost
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Oxidation efficiency of ultraviolet has been reported to be
poor.
Not promising.
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tafienucaf
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 1. 3. 2 - Ozone injection to Catalyze Oxidation of Remaining
^
Description:
Relatively small amounts of ozone are injected into the system between
the economizer and the 98% tower. The ozone in the presence of SO^
decomposes into atomic oxygen and an active O . This decomposition
reaction produces a mild shock wave which causes SO2 and O2 in the
gas to react to form SO.,. The ozone is generated separately from
oxygen in an ozonator.
Recovers:
SO2 in the form of SO3 for absorption to H2SO..
Status:
Requires testing.
Patents:
To be applied for.
Applications:
Reduce SO emission from most contact plants.
Control Level Obtainable:
About 500 ppm for SO ; no mist control.
Expected Relative Cost:
Capital Cost Average
Operating Cost Average
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Unknown-The oxidative effect of ozone in an SOo-SO- mixture has
to be tested. This type of reaction has not been reported in the
literature. A critical factor in this process is the oxidation
efficiency of the ozone because the primary cost would be the
capital and operating cost of the ozonator equipment.
Not presently feasible; may have potential.
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CONSULTING DIVISION
5ULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 1. 3. 3 - Formation of Oxysulfuric Acid to Oxidize Remaining
Description:
A portion of the SO gas mixture is bled upstream of the 98%
absorption tower. It is reacted with ozone generated with dried
air to form peroxysulfuric acid. The oxy acid is passed counter
current to the SCX-SO gas mixture in a separate section of the
98% tower. The SO2 is converted to additional acid.
Recovers:
SO0 in the form of H SO. for additional acid product.
^ ^ ~r
Status:
Requires testing.
Applications:
SO2 recovery for most contact plants.
Control Level Obtainable:
500 ppm for SO2; no mist control.
Expected Relative Cost:
Capital Cost Average
Operating Cost Average-High
Reliability:
Acid plant reliability affected by reliability of additional
equipment.
Estimated Overall Worth:
Unknown because of the following factors:
(1) Ease of conversion of O and H SO to H SO
«J £i 4 ^ U
(2) Absorption-oxidation of SO in H SO absorption
. . £ £ 0
section
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CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 1. 3. 4 - SOp-SO Conversion Improvement by Catalyst Addition
Description:
Recently constructed contact H?SO. plants can attain higher
conversions either by restricting production rate or by
additional catalyst.
Recovers:
SO in the form of H9SO for sale.
£* £ ~r
Status:
Standard practice wherever applicable.
Applications:
For contact plants that already achieve over 96% conversion, to
achieve 2, 000 ppm; improvement for any contact plant.
Control Level Obtainable:
Will have to be determined individually. Improvement to
2, 000 ppm can be expected.
Expected Relative Cost:
Capital Cost Variable-Should be on low side.
Operating Cost Very low
Reliability:
No change in reliability of existing plant.
Estimated Overall Worth:
Very good. Feasible for minor emission adjustments to most
plants. Warrants further discussion.
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CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 1. 1 - Na,,CO0 Absorption of SO^ to Produce
2 o Z ^ j
Description:
SO9 is absorbed in a concentrated sodium sulfite solution made
alkaline with sodium carbonate. A bleed stream is indirectly
heated with by-product steam from the acid plant in a scraped
surface crystallizer. The crystal slurry is centrifuged and the
crystals dried through indirect heat.
Recovers:
SO in the form of Na SO crystals for sale.
£i & O
Status:
Pilot stage for SO« absorption-theoretical for crystallization.
Patents:
Chemico applicat ions for SO_ absorption and crystallization
in venturi.
Applications:
SO9, or SO9, SOo and acid mist removal for most contact plants.
Cca trol Level Obtainable:
<100 ppm overall.
Expected Relative Cost:
Capital Cost Average
Operating Cost High-If sodium sulfite value is significantly
less than soda ash.
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Good, if sodium sulfite value is significantly greater than soda
ash, sulfate formation can be controlled and by-product steam
from acid plant can be utilized.
Feasible. Shows enough potential to warrant further
evaluation.
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CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 1. 2 - MgO Absorption of SO0 to Produce MgSO..
tL 4
Description:
SO9 is absorbed in a magnesium sulfite-oxide slurry. An oxidation
catalyst is added to the scrubbing liquid to facilitate oxidation of
sulfite. The bleed stream containing the equivalent amount of SO9
being absorbed as soluble sulfate and insoluble sulfite is fully
oxidized at 130°F in an air sparging tank. The sulfate is then
precipitated as the hydrated salt by evaporation.
Recovers:
MgSO in the form of Epsom Salts for sale.
Status:
Absorption stage piloted; oxidation stage requires testing.
Patents:
Dow patent U.S. 1, 801, 661 (1931), for sulfite oxidation.
Applications:
SO0, or SO9, SO and acid mist removal for most contact
£ & O
plants.
Control Level Obtainable:
About 100 ppm overall.
Expected Relative Cost:
Capital Cost Average
Operating Cost Average
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Good, if oxidation is efficient and there is a demand for the
MgSO . 7H O. Sulfite oxidation should be piloted.
i £
If chemical processing is wo rkable, the process would be
feasible in specific areas.
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CONSULTING DIVISION
5ULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 1. 3 - Lime Absorption of SO^ to Produce Plaster of Paris
Description:
SO is absorbed in a slurry containing hydrated lime. An oxidation
catalyst is added. The bleed stream containing mainly sulfates and
sulfites is sent to an air sparging tank to complete oxidation. The
sulfate solids are centrifuged and dried to remove free water. The
CaSO.. 2H O is then dehydrated to CaSO . 1/2H O.
* & A. £
Recovers:
SO9 in the form of plaster of paris for sale.
Status:
Absorption in use, oxidation should be checked.
Patents:
Mitsubishi may have one.
Licensor:
Mitsubishi, but there can be many variations on this theme.
Applications:
SO , or SO0, SO and acid mist removal for most contact plants.
£ £ O
Control Level Obtainable:
100 ppm overall.
Expected Relative Cost:
Capital Cost Average
Operating Cost Average
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Good if Plaster of Paris market is available for quantities.
Oxidation efficiency of sulfite is critical, as well as cost of
oxidation catalyst.
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CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2.1.4 - Absorption with Ammonia-Oxidation of (NH.)2SO~ to
Description:
SO is absorbed in a solution containing a mixture of NH HSO~,
(NH4LSO3 and (NH4)2SO4> The equivalent amount of SO
absorbed is bled from the sys tern as a mixture of bisulfute, sulfite
and sulfate. The sulfite-bisulfite is air oxidized to sulfate and
the latter is precipitated, centrifuged, washed and dried.
Recovers:
Ammonium Sulfate in the form of crystals for sale.
Status:
Piloted
Licensor:
Russian process, and others.
Applications:
Recover SO or SO9, SO and acid mist from most contact plants.
^ Li O
Control Level Obtainable:
100-200 ppm overall.
Expected Relative Cost:
Capital Cost Average
Operating Cost Average-High
Reliability:
Does not affect reliability of the acid plant.
Estimated Overall Worth:
Possible if there is a demand for ammonium sulfate.
Not promising in U.S.A.
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CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 1. 5 - SO,, to Convert Phosphate Rock to Salable Fertilizer
^
Description:
SO2 is absorbed in an NH HSO =(NH ) SO^NH^SO solution.
The sulfite-bisulfite is oxidized to sulfate and the sulfate precipi-
tated. Dried sulfate is then heated to 300°C forming NH for
recycle and ammonium bisulfate. The acidic ammonium bisulfate
is reacted with phosphate rock to form ammonium dihydrogen
phosphate, ammonium sulfate and calcium sulfate.
Recovers:
SO in the form of ammonium dihydrogen phosphate and
ammonium sulfate for sale.
Status:
Experimental
Patents:
Very probable.
Licensor:
Kiyoura-T.I. T.
Applications:
SO9 or SO9, SO™ and mist removal for most contact plants.
^ ^ O
Control Level Obtainable:
100-200 ppm overall.
Expected Relative Cost:
Capital Cost High
Operating Cost High
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Fair, ammonium dihydrogen phosphate (mono-ammonium phosphate)
may be a more desirable fertilizer product than ammonium sulfate.
Ammonium sulfate decomposition can be studied as well as
market study for fertilizer products.
Complex - not presently promising.
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CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 1. 6 - The Production of Peroxydisulfuric Acid to Absorb and
Oxidize SO0
^
Description:
SO_ is absorbed and oxidized in a scrubber with concentrated sulfuric
acid solution containing persulfuric acids and hydrogen peroxide. A
bleed stream of the concentrated H SO is passed through an electro-
lytic cell to produce the oxy acid and HO The H SO is heated to
remove oxygen before recycling to the acid plant and electrolytic cells.
Recovers:
Sulfuric acid in the form of 40-80% H SO for sale.
ct 4
Status:
Peroxide oxidation tried at bench scale.
Patents:
Simon-Carves Ltd. 930, 584 Brit.
Applications:
SO9 or SO9, SO., and acid mist recovery for most contact plants.
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CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 1. 7 - Oxidation of SO in Air-SO2 Battery
Description:
The SO gas is oxidized and hydrolyzed to H SO in the anode
compartment of an electrolytic cell. Air is passed into the
cathode compartment where the oxygen is reduced. A concentrated
H?SO product is recycled to the acid plant. Power generated by
the cell is approximately 800 KWH/Ton of SO .
Lt
Recovers:
in the form of sulfuric acid fpr recycle and sale --
D. C. power is generated.
Status:
Experimental work; "The Reaction of Sulfur Dioxide, Water and
Oxygen in an Electrolytic Cell", W. F. Seyer et al, Transactions
of the Electro Chemical Society, Vol. 91, 133-146(1947).
Applica tions:
SO2 recovery for most contact plants.
Control Level Obtainable:
Unknown
Expected Relative Cost:
Capital Cost High
Operating Cost High-Average
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Experimental.
Not presently feasible - theoretical concept.
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CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2.1.8 - Oxidation of SOg in Selenium Oxide Slurry
Description:
SO is absorbed and oxidized in a slurry of selenius acid in 30%
H9SO The SO is oxidized to H SO. and the selenium reduced
to the metal. The Se is regenerated by air oxidation.
Recovers:
SO9 in the form of sulfuric acid for sale or recycle.
Status:
German and Belgian processes.
Patents:
German 1,204,770 (1963)
Licensor:
Badische Anilin-& Soda-Fabrik A.G.
Applications:
SO9 or SO , SO and acid mist recovery from most contact plants,
& £ O
Control Level Obtainable:
100-500 ppm overall.
Expected Relative Cost:
Capital Cost Average
Operating Cost High
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Poor-Problem of contamination of H SO product with selenium
plus cost of selenium make-up at $4. 50/lb.
Not feasible - high cost of selenium.
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CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 1. 9 - SO2 Absorption with Na^COg to Produce
Description:
SO9 is absorbed in a sodium sulfite-sulfate solution made alkaline
with Na^CO-. An oxidation catalyst such as MnSO. or NaNO is
added to convert sulfite to sulfate. Oxidation is completed in an
air sparging tank. The bleed stream is then evaporated pre-
cipitating anhydrous Na SO . Thes ulfate is then centrifuged
and dried.
Recovers :
Sodium Sulfate in the form of crystals for sale.
Status:
Absorption piloted; crystallization theoretical and requires
piloting.
Applications:
SO0 or SO , SO9 and acid mist removal from most contact plants.
£* &O
Control Level Obtainable:
<100 ppm overall.
Expected Relative Cost:
Capital Cost Average
Operating Cost High-If sodium carbonate value is
significantly greater than
sodium sulfate.
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Good, if there is a demand for sodium sulfate.
Technically feasible process but there is a greater demand for
sodium sulfite. In addition, sodium sulfate has a lower market
value than sodium sulfite.
Not as promising as 2.1.1.
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CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 2. 1 - Absorption and Recovery of SO with Na SO -NaHSO,. Solution.
Description:
SO is absorbed in two stages, with sulfite-busulfite solutions. The bleed
stream from the 1st stage is steam stripped releasing SO This gas is
cooled to 100°F and dried in the 93% tower before recycle to the converter.
Sulfates can be removed with lime, or the acid mist and SO scrubbed out
prior to the absorption and an oxidation inhibitor added to the absorbant
solution.
Recovers:
SO2 in the form of a concentrated gas for recycle to acid plant.
Status:
A considerable amount of work has been done.
Patents:
H.F. Johnstone, and many others.
Applications:
SO9 or SO , SO acid mist recovery for most contact plants.
£i £i O
Control Level Obtainable:
^100 ppm overall.
Expected Relative Cost:
Capital Cost High-Average (one stage)
Operating Cost Average
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Fair; steam requirements may be excessive (12 Ibs. steam/lb. SO0)
and sulfate formation would increase capital and operating cost.
Considered because steam is available at acid plant.
Feasible process, but utilities are higher than 2.2.8.
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CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 2. 2 - SO Absorption with Na SO^-NaHSOg Solution; Recovery of
with ZnO. Sodium Sulfite-Bisulfite and Zinc Oxide.
Description:
SO is absorbed in 2 stages in a sodium sulfite-bisulfite solution. ZnO
is added to the bleed stream to react with the bisulfite to form insoluble
zinc sulfite and sodium sulfite. The ZnSO3 is calcined at 850°F to SO2
and ZnO. Sodium sulfite is recycled to the absorbers. The ZnO is
recycled and the SO? is cooled to 100 F and returned to the acid plant
drying tower. Sulfates are removed with lime, or acid mist and SO^.
scrubbed prior to the absorption step and an oxidation inhibitor added
to the absorbant solution.
Recovers:
SO2 in the form of concentrated gas for recycle to acid plant.
Status:
Johnstone Process - Worked out thoroughly in laboratory.
Patents:
H.F. Johnstone - 2,161,056 (1937)
Applications:
SO0 or SO0, SOQ and acid mist removal from contact plants.
& Lt O
Control Level Obtainable:
<100 ppm overall.
Expected Relative Cost:
Capital Cost High
Operating Cost Average-High
Reliability:
Does not. affect reliability of acid plant.
Estimated Overall Worth:
Depends upon ease of precipitation of zinc sulfite and losses of
zinc. Would probably be less feasible than steam stripping of
bisulfite-sulfite solution at acid plant sites since steam is
available. Relatively high labor requirements.
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CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 2. 3 - Absorption of SO with MnO -Mg(OH)2 and Recovery by
Calcination (GriLLo Process)
Description:
SO is absorbed by a mixture of Mg(OH) -MnO slurry. The sulfur
sau product is MgSO -MnSO which is calcined with ground coal in
a Herreshoff type furnace. The products are SO9, magnesium
manganite and ash. The magnesium manganite is separated from the
coal ash by flocculation reforming Mg(OH)9 and MnO0 for absorption.
Recovers :
SO9 in the form of concentrated gas for recycle.
£i
Status :
Pilot plant - Oct. 1967, 12, 000 CFM oil burner stack gas.
Patents:
British - 1,444,071
Licensor:
A.G. Fur Zinc Industrie
Applications :
SO0 or SO SO and acid mist recovery for most contact plants.
& Z o
Control Level Obtainable:
100-500 ppm overall.
Expected Relative Cost:
Capital Cost High
Operating Cost Average
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Fair. Reported fuel requirements for calcination are relatively low.
Capital costs high since process includes 2 spray towers and
Herreshoff type furnace, plus additional processing. Flocculation
of alkali absorbent from coal ash requires testing. Not as
promising as other processes.
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CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2.2.4 - Absorption of SO^ with NaOH solution; Recovery of SOp and
NaOH with Reducing Agent
Description:
SO9 and SO.-, is absorbed in a concentrated solution of sodium sulfite
made alkaline with sodium hydroxide. The bleed stream is heated to
1200-1400°C by the partial combustion of hydrocarbon vapors in a
reducer reactor. Molten NaOH and SO_ gas are formed. The SO9
gas is cooled and recycled to the acid plant.
Recovers:
SO,, in the form of SO0 for recycle.
^ £t
Status:
May have been piloted.
Patents:
Canadian - 817, 327 7-8-69 Wilhelm Delters
Licensor:
Inventa A.G. Fur Forschung Und Patentverwertung,
Zurich, Switzerland
Applications:
SO0 or SO0, SOQ, and acid mist recovery from most contact plants.
£ £ O
Control Level Obtainable:
<100 ppm overall.
Expected Relative Cost:
Capital Cost Average-High
Operating Cost High
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Poor
Not promising due to excessive fuel requirements. $40/ton of sulfur.
and incomplete conversion of sulfide intermediate to hydroxide.
Fuel consumption can be somewhat reduced by precipitating crystals
from the bleed stream.
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CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 2. 5 - Absorption of SO with Na CO and Reduction to Sulfur
with CO+H Reform Gas
&
Description:
SO is absorbed in a concentrated sodium sulfite solution made alkaline
with soda ash. A bleed stream is cooled to precipitate hydrated sulfite.
The sulfite is then heated to precipitate the anhydrous salt which is then
centrifuged and dried. The sulfite is then reduced to sulfide with CO and
H? and the sulfide reacted with CO and steam to form soda ash and
hydrogen sulfide. The H9S is converted to elemental sulfur.
£j
Recovers:
SO0 in the form of elemental sulfur for recycle.
£
Status:
Extensive bench scale and pilot work done by Chemico.
Patents:
Applied for.
Applications:
SO , orSO?, SO,, and acid mist recovery from sulfur contact plants.
Control Level Obtainable:
<100 ppm overall.
Expected Relative Cost:
Capital Cost Average-High
Operating Cost Average-High
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Fair; there would be reductions in capital and operating costs if
sodium sulfite crystals produced at many acid plants are processed
at a central plant. The central plant could also process crystals
from other SO2 sources as well. Few prospective users make
feasibility unlikely for acid plants.
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CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2.2.6 - Magnesium Oxide Absorption of SO^. With SO- Recovery
£ Lt
Description:
SO9 is absorbed in a magnesium sulfite-oxide slurry. The bleed
stream is centrifuged. The hydrated salt is dried and the
anhydrous sulfite calcined to magnesium oxide and SO,,. The SO2 gas
is scrubbed and the gas cooled and most of the water condensed before
recycle to the 93% tower.
Recovers:
SO in the form of concentrated gas for recycle to acid plant.
CJ
Status:
Piloted, and full-sized systems proposed. A variation in commercial
use in pulp industry.
Patents:
Several
Applications:
SO9, or SO9, SO~ and acid mist recovery from most contact plants.
•^ & O
Control Level Obtainable:
Circa 100 ppm
Expected Relative Cost:
Capital Cost Average
Operating Cost Average
Reliability:
Operates independently. Does not affect reliability of acid plant.
Estimated Overall Worth:
Good.
Feasible. Shows enough potential to warrant further evaluation.
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CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 2. 7 - Absorption and Recovery of SO0 with MgSO0-Mg(HSOJn
,-1 -i , • " «j 6 ii
Solution
Description:
SO is absorbed in a magnesium sulfite-bisulfite solution. Magnesium
oxide is added to the bleed stream precipitating magnesium sulfite.
The MgSOo is then dried and calcined to MgO and SO A portion of
the MgO produced is cycled to the scrubber to neutralize the remain-
ing bisulfite. The SO_ is cycled to the acid plant similar to the
magnesium oxide system 2. 2. 6.
Recovers:
SO9 in the form of concentrated SO gas for recycle to acid plant.
Zi £
Status:
Piloted, and full-sized systems proposed.
Patents:
Chemico
Applications:
SO0 or SO0, SOQ and acid mist recovery from most contact plants.
Li Li O
Control Level Obtainable:
<200 ppm overall.
Expected Relative Cost:
Capital Cost High-Average
Operating Cost Average
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Good; however, magnesium oxide process 2.2. 6 considered more
promising.
-------
CONSULTING DIVISION
5ULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
2. 2. 8 - Potassium Sulfite-Bisulfite
Description:
SO is absorbed in a KHSO^KpSO,, solution. The bleed stream is cooled
precipitating potassium pyrosulfife which is separated then redissolved
and steam stripped to K0SO_, releasing SO.., which is cooled to condense
moisture then cycled to the acid plant. The sulfite formed Ls recycled
to the scrubbers. Sulfates can be removed from the system with lime,
or removed prior to absorption, plus using an oxidation inhibitor with
the sulfite-bisulfite solution.
Recovers:
SO9 in the form of concentrated gas for recycle.
Li
Status:
Commercial scale unit under construction.
Patents:
Many on this type of process.
Applications:
Most sulfur and non-sulfur contact plants for recovery of SO9.
L*
Control Level Obtainable:
<100 ppm overall.
Expected Relative Cost:
Capital Cost High
Operating Cost Average
Reliability:
Operates independently.
Estimated Overall Worth:
Good - steam consumption 9 Ibs/lb SO0 for vacuum crystallization
and steam stripping.
Feasible. Shows enough potential to warrant further evaluation.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
2.29 - SO.-. Absorption with K»PO, to Form K0S,,Or and its Conversion
j. A -if o 4 Z 6 0
to Sulfur
Description:
SO is absorbed in 2 stages using K«PO as alkali makeup to form
K2§O3 and KHSOo- The bleed from the first stage with KHSOg as the
predominant solute is cooled, precipitating K^S^O^.. The K^S^O- is
heated to evolve 1/3 of the sulfur as SO9. The remainder of the
sulfur as K S O and K SO is reduced with reform gas to H9S, then
..A^^OZo £
sulfur.
Recovers:
SO0 in the form of sulfur for recycle.
£
Status:
Small scale testing has been done.
Patents:
TVA
Licensor:
TVA
Applications:
SO0, or SO0, SOQ and acid mist recovery from most contact plants.
^ ^ o
Control Level Obtainable:
<100 ppm overall.
Expected Relative Cost:
Capital Cost High
Operating Cost High
Reliability:
Does not affect reliability of the acid plant.
Estimated Overall Worth:
May have poor absorption efficiency due to build-up of phosphoric
acid. Costly; pyrosulfite crystals should be processed at a central
plant as suggested for process 2. 2. 5.
Not presently promising.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
2.2. 10 - Absorption of SO2 by K^SO -KHSO,,; Recovery of SO2 with
Aldehyde Bisulfite
Description:
SO~ is absorbed in a potassium sulfite-bisulfite solution. An organic
such as an aldehyde is added to the bleed stream precipitating an
aldehyde-bisulfite addition product which is then heated to release
SO and form a separated sulfite and aldehyde v\h ich are recycled.
The SO~ is cooled to 100°F and is then sent to the acid plant drying
tower.
Recovers:
SO9 in the form of concentrated gas for recycle.
^
Status:
Theoretical
Patents:
None so far on this method.
Applications:
SO , or SO , SO and acid mist recovery from most contact plants.
£ Z o
Control Level Obtainable:
<100 ppm overall may be possible.
Expected Relative Cost:
Capital Cost High
Operating Cost Average-High
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Unknown - precipitation of organic bisulfite and decomposition of
same has to be proven.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
2.2.11 - Absorption with Ammonia - Recovery of SO? from Ammonia
Bisulfite
Description:
SO is absorbed in an ammonium sulfite-bisulfite solution. The bleed
stream is steam stripoed releasing a concentrated SO gas which is
cooled to condense most of the moisture before recycle to the acid
plant.
Recovers:
SO in the form of concentrated gas for recycle to acid plant.
Lt
Status:
Laboratory development.
Patents:
U.S. -2, 233,-841 (1941) and many others.
Applications:
SO0, or SO , SO and acid mist recovery for most contact plants.
£ £ O
Control Level Obtainable:
About 100 ppm overall.
Expected Relative Cost:
Capital Cost Average
Operating Cost Average
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Fair - similar to the sodium and potassium sulfite and bisulfite
processes, but absorbing solutions would be higher in bisulfite to
prevent the release of NH? into the SO_ free off gas. This, in
turn, reduces absorption efficiency.
Not very promising.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
2. 2. 12 - Absorption of SOg with Ammonium Sulfite and Bisulfite;
Recovery of SO9 with ZnO
^
Description:
SO9 is absorbed in an ammonium sulfite-bisulfite solution. Ammonia
is added equivalent to the SO absorbed. Zinc Oxide is added to the
bleed stream precipitating zinc sulfite and producing ammonium
hydroxide. The solution is heated to evolve NH« for recycle. The
ZnSO precipitate is then calcined to release SO- and regenerate zinc
oxide. The SO9 is cooled to condense moisture before recycle.
^
Recovers:
SOn in the form of concentrated SO0 gas for recycle.
&
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
2. 2. 13 - Absorption of SO9 with Manganese Oxides with Recovery of p
From MnSO
Description:
SO9 is absorbed in a slurry of manganese oxides with the formation of
soluble manganese sulfate which is bled from the system. The bleed
solution is heated precipitating anhydrous MnSO. which is separated
by centrifuging. It is then calcined at 1, 000°C releasing SO and
forming manganese oxides which are recycled. The SO is then water-
cooled to 100°F and then cycled to the acid plant.
Recovers:
SO9 in the form of concentrated gas for recycle.
Li
Status:
TVA-Piloted using counter-current absorption tower.
Patents:
U.S. -2,984,545 (1961) (TVA)
Licensor:
TVA
Applications:
SO0 or SO9, SOq and acid mist recovery from most contact plants.
Li £i O
Control Level Obtainable:
100-500 ppm overall.
Expected Relative Cost:
Capital Cost High
Operating Cost Average
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Poor - Problems in regeneration of manganese oxides absorbent
were encountered.
Not promising.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 2. 14 - SO.-, Absorption in and Recovery From Methylammonium
Sulfite-Bisulfite Solution
Description:
SO2 is absorbed in methylammonium sulfite-bisulfite in two stages. A
bleed stream containing the equivalent methylammonium bisulfite is
steam stripped producing methylammonium sulfite and releasing SO9.
The former is returned to the scrubber and the SO9 cooled to about
100°F to condense most of the HO before cycling to the acid plant. An
oxidation inhibitor is added to the absorbing solution to reduce sulfate
formation. Acid mist and SO_ are scrubbed out prior to absorption.
o
Recovers:
SO9 in the form of concentrated gas for recycle.
Status:
Johnstone test data. Should be piloted.
Patents:
Possible Johnstone Patent circa 1940
Applications:
SO0 or SO0, SOQ and acid mist recovery from most contact plants.
^ ^ o
Control Level Obtainable:
As low as 100 ppm overall.
Expected Relative Cost:
Capital Cost Average
Operating Cost Average
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Good. Steam requirements for desorption are a little high (18 Ibs/lb.
SOp). Methylamine vapor pressure in methylammonium sulfite-
bisulfite is neglibible at absorption temperatures.
Feasible. Shows enough potential to warrant further evaluation.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 2. 15 - SO2 Absorption in and Recovery From a Xylidine-Water
Mixture (Sulphidine Process)
Description:
SO9 is absorbed in a xylidine-water mixture. The xylidine sulfite is
wafer soluble and is steam stripped releasing SO2 and returning
xylidine to the scrubber. The SO9 is cooled then cycled to the acid
plant. Some of the xylidine which is toxic can be vaporized into the
flue. An additional absorption stage is required.
Recovers:
SO9 in the form of concentrated gas for recycle.
Status:
Process developed in Germany.
Patents:
Probably German patents.
Licensor:
Lurgi
Applications:
SO9, or SO0, SOQ and acid mist recovery from most contact plants.
£ £ O
Control Level Obtainable:
100-500 ppm overall.
Expected Relative Cost:
Capital Cost Average
Operating Cost High
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Poor; second scrubbing stage required using organic alkali and
xylidine sulfate formation requiring Na CO~ or Na SO., for
regeneration.
Not promising because of volatility, toxicity and sulfate
removal problems.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2.2.16 - Sodium-Barium Salt System for Absorption of SO? and its
Recovery As Sulfur
Description:
SO~ is absorbed in a solution of NaSOo kept at the neutral point with
Na CO . Barium sulfide is added to me Na SO precipitating BaSO
and producing Na~S. The BaSO,, is reduced to BaS which is recycle
The Na S is converted to alkali {which is also recycled) and H2S
which is converted to elemental sulfur.
Recovers:
SO0 in the form of elemental sulfur for recycle to plant.
Lt
Status:
Laboratory work at Chemico.
Patents:
To be applied for, and 1938 patent.
Applications:
SO0 removal from most sulfur burning contact plants.
^
Control Level Obtainable:
<100 ppm overall.
Expected Relative Cost:
Capital Cost High-Average
Operating Cost High-Average
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Good if barium sulfite crystals are reduced to sulfide at central
process plant to reduce costs. Not promising for most acid
plants.
Similar to Na CO -S° process 2. 2. 5.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 2. 17 - Sodium-Barium Salt System for Absorption and Recovery
of S02
Description:
SO is absorbed in a solution made alkaline with NaOH. The bleed
stream containing a Na?SO« solution is reacted with barium oxide
precipitating barium sulfite and producing NaOH with the latter
recycled to the scrubber. The barium sulfite is reduced to sulfide
and the latter is then roasted to SO^ and BaO. The SO is cleaned
and then cooled to condense moisture before recycle.
Recovers:
SO_ in the form of concentrated gas for recycle to acid plant.
u
Status:
Laboratory work at Chemico on barium salt precipitation.
Applications:
SO9 or SO SO, and mist recovery from most contact plants.
L* Li O
Control Level Obtainable:
^100 ppm overall.
Expected Relative Cost:
Capital Cost High
Operating Cost Average
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Poor. Sulfite has to be reduced in order to release the SO .
^
Not promising.
Additional processing required in comparison to other processes
involving the calcination of a salt to release SO .
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 2. 18 - Absorption of SOp with Barium Hydroxide and its Recovery
from BaSOn-BaSD
o 4
Description:
SO9 is absorbed in a solution made alkaline with barium hydroxide
forming insoluble barium sulfite and sulfate. This material is
bled from the scrubber, settled out and centrifuged. It is then
reduced and roasted to release the SO9.
^
Recovers:
SO in the form of concentrated gas for recycle.
LJ
Status:
Laboratory work at Chemico on barium salt precipitation.
Applications:
SO9, or SO0, SO,, and acid mist recovery from most contact
Z / 6
plants.
Control Level Obtainable:
<100 ppm overall.
Expected Relative Cost:
Capital Cost Average-High
Operating Cost Average-High
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Poor, sulfite must be reduced in order to release SOQ.
<£
Not promising.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2.2. 19 - Absorption of SO in FejSO^g. FeSO4. and H2SO4 liquid,
and its recovery from FeSO4
Description:
SO is absorbed and oxidized in a scrub bing liquid containing FeSO.,
Fe'(SOJ3, and H SO . The SO is oxidized to f^SO^ and the Fe2(SO ) ,
reduced to FeSO . The FeSO is calcined to SO , SO and Fe O. The
gas is cooled, removing the SO as H SO , and me SO is cycfedio the
acid plant. The Fe O is reacted with a bleed stream containing dilute
H SO and iron salts at elevated temperatures of about SOQop to reduce
acidity level.
Recovers:
SO,-, in the form of SO and SOQ gas for recycle.
Z Z
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2.2.20 - Liquid Phase Oxidation of SO2 with Ozone
Description:
Ozone is mixed with the exiting gases and sparged into a sulfuric
acid solution. The SO.-, is oxidized to H?SO. and the acid produced
is cycled to the 93% tower.
Recovers:
SO9 in the form of H9SO. for recycle.
^ LA ~t
Status:
Experimental
Patents:
Many
Applications:
Most sulfur and non-sulfur contact plants for reduction of SO2 emission.
Control Level Obtainable:
100-500 ppm SO may be possible; no mist control.
Expected Relative Cost:
Capital Cost Average-High
Operating Cost Average-High
Reliability:
Does not affect operation of acid plant.
Estimated Overall Worth:
Many unknown factors, including capital cost, oxidation efficiency
(which must be well over 100%), the consequences of dissolved O
in H9SO and pressure drop in oxidation system. Pilot testing
would be required.
Not presently feasible.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2.2.21 - Activated Charcoal Slurry Absorption and Recovery of SO
£
Description:
SO0 is absorbed in a slurry of absorbant carbon. The bleed stream
containing equivalent SO9 is centrifuged and the charcoal mass is
heated to release adsorbed SO9 and regenerate the charcoal.
£
Recovers:
SO9 in the form of concentrated gas for recycle to acid plant.
<£
Status:
Absorption piloted, regeneration unknown.
Patents:
Japan - 174,880 (1948)
Licensor:
Toa Gosei K.K.
Applications:
SO0 recovery for most contact plants. Separate mist control advisable.
Control Level Obtainable:
100 to 500 ppm for SO2>
Expected Relative Cost:
Capital Cost Low-Average
Operating Cost Average-High
Reliability:
Does not affect efficiency of acid plant.
Estimated Overall Worth:
Processing problems - active life of charcoal and its absorptive
capacity; could be piloted.
Does not look too promising.
-------
CONSULTING DIVISION
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2.2.23 - Adsorption and Recovery of SO? with Activated Char
(Reinluft Process)
Description:
SO is absorbed and oxidized to H SO on activated char. The char
is Heated to 700°F reducing the HJ3O to SO A bleed stream
containing hot SO9 and CO9 gases is cycled to the acid plant.
L* £t
Recovers:
SO0 in the form of concentrated gas for recycle to acid plant.
£i
Status:
Large pilot unit.
Patents:
Yes
Applications:
SO0, SOQ and acid mist removal from most contact plants.
^ o
Control Level Obtainable:
100-500 ppm overall.
Expected Relative Cost:
Capital Cost High
Operating Cost High
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Poor - pilot units tested had operating difficulties.
Not feasible because of the operating difficulties and relatively
large amount of char consumed as the reducing agent.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 2. 24 - Adsorption of SO2 with Dry H.ydrated Lime with
Recovery by Calcination
Description:
SO9 is absorbed in a bed of dry hydrated lime. The spent sulfite
ana sulfate is calcined to lime which is then hydrated and recycled
to the adsorber. The SO9 is scrubbed and cooledand cycled to the
acid plant. Carbon is added to the calciner for reduction of CaSO..
Recovers:
SO9 in the form of concentrated gas for recycle.
^
Status:
Idea
Applications:
SO9 and mist removal from most contact plants.
Control Level Obtainable:
100-500 ppm overall may be possible.
Expected Relative Cost:
Capital Cost Average
Operating Cost Average-High
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Unknown
Not presently promising. Requires extensive piloting to determine
feasibility.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2.2.25 - Adsorption and Recovery of SO0 with Silica-Alumina Alkali
4U "
Description:
o
The off-gases from the plant are heated to 600-800 F and passed over
a fluidized silica alumina bed containirg copper, chromium and
barium. The adsorbant is regenerated at 675-825°F using H_, CO or
CH4- Sulfur is released as S°, SC>2 and H2S. The H2S and go are
burned and all the SO is recycled.
£i
Recovers:
SO in the form of SO for recycle.
& £
Status:
Tested
Patents:
French - 1,448, 396
Licensor:
Shell Internationale Research Maatschappij N. V.
Applications:
SO0, SO,, and mist recovery from H S and sludge burning plants.
^ O &
Control Level Obtainable:
Probably to 100 ppm and lower, overall.
Expected Relative Cost:
Capital Cost High
Operating Cost High
Reliability:
Operates independently. Does not affect reliability of acid plant.
Estimated Overall Worth:
Poor - reducing agent is required plus adsorption at 600-800°F.
In addition, there might be high attrition of the adsorbant.
Not promising.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 2. 26 - Adsorption and Recovery of SO2 with Alkalized Alumina
Description:
SO is adsorbed by Na O-A19O pellets in a dry contactor forming
Na2SO -Al-O . The pellet stream is bled into a reactor where
reform gas reduces the sulfate to the oxide and releases H9S
which is recycled to the acid plant. The regenerated Na O-A1 O
pellets are recycled to the dry contactor.
Recovers:
SO9 in the form of H S for recycle.
& £i
Status:
Piloted by Bureau of Mines.
Patents:
Many
Licensor:
CEGB-England
Applications:
SO recovery from most H S and sludge burning contact plants.
Control Level Obtainable:
About 100 ppm
Expected Relative Cost:
Capital Cost Average-High
Operating Cost High
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Poor - excessive losses of alkalized alumina absorbant has made
the process impractical.
Not feasible.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 2. 27 - Adsorption of SO,., with Dry Magnesia and Recovery from
MgS00-MgSO,
— o 1—
Description:
SO2 is chemically adsorbed by a mixture of dry MgO-MgSO -MgSO
co-current in an adsorption tower. The exiting gas-solid mixture
is separated. The MgO-MgSO„-MgSO. is sent to a calciner where
SO is released and the MgO is recycled. SO2 is cleaned, cooled
ana cycled to the acid plant.
Recovers:
SO2 in the form of concentrated gas for recycle.
Status:
Process Piloted
Patents:
Applied for.
Licensor:
Showa Hatsuden, subsidiary of Showa Denko, K. K.
Applications:
SO9 recovery from most contact plants.
Ci
Control Level Obtainable:
500 ppm SO only.
^
Expected Relative Cost:
Capital Cost Average
Operating Cost Average
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Unknown - adsorption stage would have to be piloted with the goal
of 95% removal of SO9. Dry adsorption type process is favorable
for acid plant control since there is no moisture in the incoming
gases.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2.2.28 - Absorption with Basic Aluminum Sulfate Solution,
Regeneration with Heat to Release SO
(Hardman Holden)
Description:
Sulfuric acid tail gas is scrubbed with a basic aluminum sulfate
solution. SO~ is recovered by steam stripping and recycled to
the drying tower. SO,, and acid mist must be removed before
scrubbing.
Recovers:
SO9 in the form of concentrated gas for recycle.
Status:
In commercial operation (Europe), for SO production from sulfur.
Patents:
Many; U.S., British, German, Australian
Licensor:
Hardman Holden Ltd.
Applications:
SOO recovery from any contact acid plant.
Control Level Obtainable:
500 ppm or lower for SO and mist.
Expected Relative Cost:
Capital Cost Low
Operating Cost Average
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Good - Feasible, but SO and acid mist must be removed prior
to scrubbing to minimize sulfate formation.
Shows enough potential to warrant further evaluation.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 2. 29 - Resin Adsorption of SOp
Description:
SO is adsorbed by an ion-exchange resin. The resin is regenerated
with hot air. Acid mist removed first by decomposition with heat to
H2O and SOo, and SO3 is adsorbed by separate adsorbent.
Recovers:
SO in the form of SO for recycle to the acid plant; removes SO~
and acid mist.
Status:
Laboratory development.
Patents:
U.S. patent pending for resin.
Licensor:
Rohm & Haas (resin)
Applications :
SO0 recovery and acid mist removal from any contact acid plant.
(4
Control Level Obtainable:
200 ppm or lower depending on regeneration cycle.
Expected Relative Cost:
Capital Cost Medium
Operating Cost Low
Reliability:
High, independent operation does not affect acid plant reliability.
Estimated Overall Worth:
Good - further development required for SO- removal step.
«j
Shows enough potential to warrant further evaluation.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 2. 30 - Adsorption of SQ9 with a Molecular Seive
&
Description:
- is adsorbed in a highly acid resistant synthetic variety of a
mineral molecular sieve characterized with high pore properties.
The molecular seive is regenerated with hot gas at temperatures
as low as 200°C.
Recovers:
SO in the form of dilute gas.
£
Status:
Laboratory work has been done.
Patents:
Norton Company
Applications:
SO_ removal from most contact plants.
£i
Control Level Obtainable:
Unknown.
Expected Relative Cost:
Capital Cost Average
Operating Cost Low
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Unknown.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. /. 3. 1 - Absorption of SO0 with Acetic Acid Solubilized Limestone Slurry
£
Description:
SO? is absorbed in a limestone slurry containing a small amount of
acetic acid. The bleed stream containing mainly sulfites and sulfates
is sent to a clarifier. The underflow is centrifuged and solids sent to
waste disposal. The supernatent liquid containing acetic acid is
recycled.
Recovers:
SO in the form of calcium magnesium sulfites and sulfates for
disposal.
Status:
Bench scale tests for absorption of SO and solubility of limestone in
acetic acid.
Patents:
Chemico patent applied for.
Applications:
SO0 or SO0, SOn and acid mist removal for most contact plants.
£* £ O
Control Level Obtainable:
200-300 ppm overall.
Expected Relative Cost:
Capital Cost Low
Operating Cost Average
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Good, if SO? emissions are relatively low, inexpensive limestone
is available and solids can easily be disposed of. Limestone
solubility and acetic acid volatility requires evaluation in a pilot
scrubber. The acetic acid reduces the variability of limestones
with regard to their alkali consumption efficiencies and SO9
absorption efficiencies. Acetic acid volatility would be minimal
since the absorbing slurries would be at about 75°F.
Too many unknowns for further evaluation here.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2.3.2 - Absorption of SOp in Limestone Slurry
Description:
SO_ is absorbed in a limestone slurry. The bleed stream containirg
mainly sulfites and sulfates is sent to a clarifier. The underflow is
centrifuged and the solids sent to solid waste disposal. The super-
natent liquids are recycled.
Recovers:
SO in the form of calcium and magnesium sulfite and sulfate for
disposal.
Status:
Has been piloted for utility applications.
Patents:
Many
Applications:
SO9, SO,, and acid mist removal from most contact plants.
Z o
Control Level Obtainable:
500 ppm or lower overall.
Expected Relative Cost:
Capital Cost Low
Operating Cost Average-High
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Good if regulations are not too strict, inexpensive limestone is
available, and the solids can be easily disposed of.
SO absorption efficiency may not be as high as desired.
£
Not as promising as 2. 3. 3.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 3. 3 - Lime Absorption of SO..
' £t
Description:
SO9 is absorbed in a slurry containing hydrated lime. The bleed
stream which contains mainly sulfites and sulfates is sent to a
clarifier. The underflow is centrifuged and the solids sent to
waste disposal. The supernatent liquid is recycled.
Recovers:
Calcium sulfites and sulfates in the form of solids for
disposal.
Status:
In use on utility boilers in similar process.
Patents:
Many
Applications:
Most sulfur and non-sulfur contact plants.
Control Level Obtainable:
Circa 100 ppm possibly lower.
Expected Relative Cost:
Capital Cost Low
Operating Cost Average-High
Reliability:
Operates independently.
Estimated Overall Worth:
Good if SO_ emissions are relatively low and solid waste disposal
facilities are available.
Feasible. Shows enough promise to warrant future evaluation.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2.4.1 - Absorption and Recovery of SO9, and Production of Na SO.
& £ rr
Description:
SO2 is absorbed in a sodium sulfite solution with the entering Na2CO^
neutralizing the bisulfite formed. Sulfuric acid is added to the bleed
stream releasing SO and forming sodium sulfate. The SO,., is highly
concentrated and is sent to the 93% tower to remove any moisture
before recycle to the converter. The Na SO . solution is evaporated
precipitating anhydrous crystals.
Recovers:
SO in the form of concentrated SO gas and salt cake for recycle
and sale respectively.
Status:
Absorption piloted, crystallization industrial process.
Patents:
Many
Applications:
SO0, or SO0, SO~ and acid mist removal from most contact plants.
£1 £ O
Control Level Obtainable:
100 ppm overall.
Expected Relative Cost:
Capital Cost Average
Operating Cost High
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Technically good but poor economics. Similar to sodium sulfate
process 2. 1.9, plus the cycling of SO9.
u
Not as promising as sodium sulfate process 2. 1. 9 because H SO .
is consumed to produce Na_SO..
£ ~r
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2.4.2 - Absorption and Oxidation of SO Producing MgSO From
MgO
Description:
SO is absorbed in two stages. In the first a dilute EUSO solution
containing MnSO. catalyst absorbes and oxidizes 1/2 flie sulfur values
entering the system. The remaining SO~ gas is absorbed in a
magnesium sulfite-oxide slurry. The acid in the first stage is
reacted with the MgSO,-, from the second forming MgSO. and SO2.
The MgSO is crystallized and the SO2 recycled.
Recovers:
SO2 in the form of SO2 gas for recycle and MgSO ?H2O for
sale.
Status:
Idea
Patents:
None
Applications:
SO0, or SO0, SO.-, and acid mist recovery from most contact plants.
^ ^ O
Control Level Obtainable:
100 ppm overall.
Expected Relative Cost:
Capital Cost Average
Operating Cost Average-Low
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Fair, 1/2 SO? returned to plant. Dilute impure acid is utilized to form
a fairly pure magnesium sulfate which can be sold. Only 50% absorp-
tion of SO9 is required in the first stage where absorption is difficult.
At an acia plant there are no phenols to inhibit oxidation as with coal-
fired boilers. Dilute MgSO. solution would be formed requiring con-
siderable evaporation for crystallization since the acid formed is
dilute.
Magnesium sulfate has a limited market (Process 2. 1.2). Not
promising.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2.4. 3 - Fulham Simon-Carves; Production of Sulfur and (NH ) SO
from (NH,LSO0-NH,HSO0 Solution
TC & o 4 o
Description:
SO~ is absorbed in an ammonium sulfite-bisulfite solution. A
relatively small amount of sulfuric acid is added to the bleed stream
and the material autoclaved. Ammonium sulfate and elemental
sulfur are produced at a weight ratio of 13 to 1.
Recovers:
SO in the form of sulfur and (NH ) SO for recycle and sale.
respectively.
Status:
Pilot stage.
Patents:
British 525,883 (1940)
Licensor:
Fulham Simon-Carves Ltd.
Applications:
SO or SO , SO... and acid mist recovery from most sulfur burning
contact plants.
Control Level Obtainable:
100 ppm overall.
Expected Relative Cost:
Capital Cost High
Operating Cost High
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Fair - There is little demand for ammonium sulfate which is the
principal product. A relatively small amount of S° is recycled.
Not as promising as other systems.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2.4.4 - Absorption of and Recovery of SO? Using (NH ) SO -
NH HSO and H SO
Description:
SO is absorbed in an ammonium sulfite-bisulfite solution. Sulfuric
acid is added to the bleed stream releasing SO and forming
ammonium sulfate. The SO is highly concentrated and is sent to
the 93% tower to remove any moisture before recycle to the
converter. The ammonium sulfate is crystallized from solution.
Recovers:
SO in the form of concentrated gas for recycle and
(NH.LSO for sale.
TI ^ Tc
Status:
In Use
Patents:
Cominco
Licensor:
Cominco
Applications:
Most sulfur and non-sulfur contact plants.
Control Level Obtainable:
Circa 100 ppm
Expected Relative Cost:
Capital Cost Average
Operating Cost High
Reliability:
Operates independently.
Estimated Overall Worth:
Fair; high operating costs, H~SO. and NH., raw materials,
ammonium sulfate product.
Not promising except under special circumstances where it may
be quite attractive.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 4. 5 - Ammonium Sulfite-Bisulfite Absorption with SO? Recovery
and NH.NOp Production
Description:
SO? is absorbed in two stages in solutions of ammonium sulfite-
bisulfite. Nitric acid is added to the ammonium sulfite-bisulfite
bleed stream releasing SO? for recycle and forming ammonium
nitrate. The ammonium nitrate in solution form is concentrated
for sale. Ammonium sulfate formed is removed with the nitrate
product.
Recovers:
Concentrated SO9 for recycle and ammonium nitrate for sale.
^
Status:
In commercial operation in Europe.
Licensor:
SCHZ (Czechoslovakia)
Applications:
SO9, SO., and acid mist recovery from most contact plants.
& \J
Control Level Obtainable:
About 100 ppm overall.
Expected Relative Cost:
Capital Cost High
Operating Cost High
Reliability:
Operates independently. Does not affect reliability of acid plant.
Estimated Overall Worth:
Good in locations where there is demand for NH.NOo solution.
Feasible. Shows enough potential to warrant future evaluation.
-------
CONSULTING DIVISION
5ULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 2. 4. 6 - Sulfuric Acid-Lime 2 Stage Absorption to Recover SO and
Produce Plaster of Paris
Description:
SO? is absorbed in 2 stages. In the first, a 10% H2SO. solution
containing MnSO . catalyst absorbs and oxidizes half the sulfur
values entering the system. The remaining sulfur value is
absorbed in the second stage with lime. The acid is then reacted
with the CaSO~ product to form SO~ which is recycled, and
CaSO4-2H2O which is calcined to CaSO4-l/2H2O.
Recovers:
Concentrated SO for recycle and plaster of paris for sale.
^
Status:
Idea
Patents:
Russian #50446 (1937)
Applications:
SO0, SOQ and acid mist recovery for most contact plants.
^ o
Control Level Obtainable:
<100 ppm overall.
Expected Relative Cost;
Capital Cost Average
Operating Cost Average-High
Reliability:
Operates independently. Does not affect reliability of acid plant.
Estimated Overall Worth:
Good. Shows enough potential to warrant further evaluation.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 3. 1. 1 - Dual Pad Mist Separator
Description:
Acid mist impinges on filaments of horizontal mesh pads located
in top of the absorption tower to form large droplets which are
returned to the tower by gravity.
Recovers:
H SO. mist in the form of H9SOA for sale as product.
^4 <^ Tt
Status:
Many types in commercial operation.
Patents:
Many.
Applications:
Recovery of acid mist particles >3 microns from most acid
plants not producing oleum.
Control Level Obtainable:
Reduce acid mist to 2 mg/ACF.
Expected Relative Cost:
Capital Cost Low
Operating Cost Low
Reliability:
High - Does not affect acid plant reliability.
Estimated Overall Worth:
Good - Feasible within its range of capability. Low gas
velocities required.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 3.1.2 - Tubular Type Mist Separator
Description:
Tail gas from the absorption tower passes through glass fiber
packed vertical tubular elements. Recovered acid mist flows
down the inside of the elements and is returned to the tower as
liquid.
Recovers:
H SO. mist in the form of H SO. for sale.
LJ TC ^ TT
Status:
In commercial operation.
Patents:
Several.
Licensor:
Monsanto (Brinks High Efficiency)
Applications:
Recovery of acid mist for most acid plants.
Control Level Obtainable:
Reduce acid mist emission to <0. 1 Mg/SCF.
Expected Relative Cost:
Capital Cost Average
Operating Cost Low
Reliability:
High - Does not effect plant efficiency.
Estimated Overall Worth:
Good. Feasible.
Can be accommodated within the absorber in new plants.
Existing plants require separate unit.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 3. 1. 3 - Panel Type Mist Separator
Description:
Tail gas from the absorption tower passes through vertical fiber
panels into a chamber. Tail gas is discharged upward and collected
mist as liquid is collected in a drain line and returned to the absorber.
Recovers:
Acid mist in the form of H SO for sale.
ij ^r
Status:
In commercial operation.
Patents:
Several.
Licensor:
Monsanto (Brinks High Velocity)
Applications:
Acid mist recovery for most acid plants.
Control Level Obtainable:
Reduce acid mist emission to <0. 5 Mg/SCF.
Expected Relative Cost:
Capital Cost Low-Average
Operating Cost Low
Reliability:
High - Does not affect acid plant reliability.
Estimated Overall Worth:
Good - Feasible.
Can be accommodated within the absorber in new plants; existing
plants require a separate unit.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 3. 2. 1 - Electrostatic Precipitation
Description:
Tail gas is passed through a chamber with electrostatic elements.
Mist particles collect on the elements and fall as liquid to the
bottom of the chamber and are returned to the acid plant.
Recovers:
H SO mist in the form of H SO for sale.
^4 ^4
Status:
In commercial operation.
Patents:
Many.
Applications:
Acid mist recovery for most acid plants.
Control Level Obtainable:
To 99% mist removal. Near 100% for <3 micron mist.
Expected Relative Cost:
Capital Cost Average-PIigh
Operating Cost Average-High
Reliability:
Good - Does not affect reliability of acid plant.
Estimated Overall Worth:
Good- Feasible
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 3. 3. 1 - Mist Removal With Venturi Scrubber
Description:
H SO mist is entrained in a venturi scrubber operating at high pressure
drop (30" to 40" HO). The scrubbing liquid may be water or H SO
The bleed stream can be neutralized with alkali and the salt disposed of
if applied to a contact plant. This is not necessary with a concentrator.
Recovers:
Acid mist in the form of CaSO . for disposal, or weak acid for
concentration.
Status:
Venturi scrubbers are in commercial operation on concentrators.
Patents:
Many
Applications:
All acid plants except oleum for acid mist control.
Control Level Obtainable:
<3 Mg H SO./SCF
&* 4
Expected Relative Cost:
Capital Cost Average-High
Operating Cost Average
Reliability:
High. Does not affect reliability of acid plant.
Estimated Overall Worth:
Good for elimination of most acid mist problems, but more costly than
3.1.1 for equal control on a contact plant.
Feasible for concentrators (classifications 1. 5 and 2. 5).
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 3.4.1 - Absorption and Neutralization of Acid Mist and SO,, with Lime
O
Description:
Lime as fine dust is injected into the tail gas upstream of a venturi
scrubber. The lime reacts with the acid mist and SO, vapor to
form CaSO which is removed in the venturi. The scrubbing
medium is a CaSO. slurry in H SO .
~r ^4
Recovers:
H SO mist and SO in the form of CaSO for disposal.
^4 o 4
Status:
Some laboratory work has been done.
Applications:
All acid plants for removal of SO- and acid mist.
Control Level Obtainable:
Extent of lime dust - SO,, reaction unknown because of low tempera-
ture of acid plant, tail gas.
Expected Relative Cost:
Capital Cost Low
Operating Cost Average
Reliability:
Operates independently. Does not affect reliability of acid plant.
Estimated Overall Worth:
Unknown. Pilot testing required.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 4. 1. 1 - Absorption of NO and SO0 with Solid MgSO0 and MgO
J£ £ -j
Description:
Gases are passed upward through a bed of lump MgSO.,-MgO.
Water is sprayed downward to wet the surface of the sulfite to
enhance the absorption reaction as well as to dissolve the
sulfate formed. The sulfite reduces the NO to N~ and SO? is
neutralized by MgO.
Reduces:
NO to N9 and removes SO0 as MgSO for disposal.
X ^ ^ ~r
Status:
Idea
Patents:
None
Applications:
SO0 and NO control for chamber acid plants.
£t X
Control Level Obtainable:
Unknown
Expected Relative Cost:
Capital Cost Average
Operating Cost Average-High
Reliability:
Operates independently. Does not affect reliability of acid
plant.
Estimated Overall Worth:
Unknown. Would require piloting.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 4. 1. 2 - Redaction of NO and Absorption of SQ? with Sulfite-
Carbonate Solution
Description:
Nitrogen oxides and SO are absorbed in a venturi scrubber using
inorganic aqueous sulfife-carbonate solution. The NO is
converted to N and sulfites to sulfates. The SO9 converts
carbonates to sulfites.
Recovers:
NO and SO9 in the form of N_ + sulfate salt for disposal of sulfate
salt. N vented to atmosphere.
^
Status:
Tested
Patents:
British 1,134,881
Licensor:
Societa Industriale Catanese S.p. A. , Palermo, Italy
Applications:
Chamber acid plant for SO and NO control.
£* X.
Control Level Obtainable:
NO to about 200 ppm; SO <100 ppm.
X ^
Expected Relative Cost:
Capital Cost Low-Average
Operating Cost Average-High
Reliability:
Does not affect reliability of acid plant.
Estimated Overall Worth:
Unknown. Nitric oxide difficult to entrain for reduction. Scrubbing
solution may require large excess of sulfite for efficient absorption.
Piloting required.
Not presently feasible.
-------
CONSULTING DIVISION
SULFURIC ACID PLANT
EMISSION CONTROL PROCESS SURVEY
No. 4. 1. 3 - Absorption of SO and NOX with Sodium Hydroxide
Description:
Nitrogen oxides and SO~ are absorbed in HaOH, using two counter-
current absorption towers in series, to form Na^SO^, NaNO9 and
NaNO . NaNO catalyzes the oxidation of Na SO to Na SO . The
absorbent contains NaNO , NaNO Na SO and free NaOH. A
bleed stream is evaporated and crystallized to produce a salt
mixture for sale or disposal.
Recovers:
SO and NOX as a sodium salt mixture for sale or disposal.
£t
Status:
Some laboratory work has been done.
Patents:
Probably
Applications:
SO and NOX control for chamber acid plants.
£i
Control Level Obtainable:
200 ppm NOX, 100ppmSO2.
Expected Relative Cost:
Capital Cost Average-High
Operating Cost High
Reliability:
Operates independently. Does not affect reliability of the acid
plant.
Estimated Overall Worth:
Unknown.
Costly; not promising.
-------
CONSULTING DIVISION
TABLE A-l
ESTIMATED CAPITAL COST
1.2. 1/1.2 (250)
4, OOP ppm INITIAL EMISSION LEVEL
500 ppm CONTROL EFFECTIVENESS
Equipment - SO Removal
SO~ Recovery
Sub Total $254,000
Civil Works 40, 000
Buildings -0-
Insulation 31,000
Piping and Ductwork 129, 800
Instrumentation 14,400
Electrical 20, 600
Miscellaneous and Catalyst 23, OOP
Total $512,800
TABLE A-2
ESTIMATED CAPITAL COST
1.2. 1/1. 1 (250)
5. OOP ppm INITIAL EMISSION LEVEL
500 ppm CONTROL EFFECTIVENESS
Equipment - $254,000
Civil Works 40, 500
Buildings -0-
Insulation 31,000
Piping and Ductwork 130, 000
Instrumentation 14,400
Electrical 20, 500
Miscellaneous and Catalyst 24, 600
Total $515,000
-------
CONSULTING DIVISION
TABLE A-3
ESTIMATED CAPITAL COST
1.2. 2/1. 1 (50)
5. OOP ppm INITIAL EMISSION LEVEL
500 ppm CONTROL EFFECTIVENESS
Equipment $134,600
Civil Works 18, 700
Buildings -0-
Insulation 13,000
Piping and Ductwork 60, 000
Instrumentation 14, 600
Electrical 9, 700
Miscellaneous and Catalyst 9, 400
Total . . $260,000
TABLE A-4
ESTIMATED CAPITAL COST
1. 2. 2/1. 2 (250)
4, OOP ppm INITIAL EMISSION LEVEL
500 ppm CONTROL EFFECTIVENESS
Equipment $236, 500
Civil Works 41,200
Buildings -0-
Insulation 26,200
Piping and Ductwork 106, 400
Instrumentation 14,400
Electrical 20, 700
Miscellaneous and Catalyst 36, 700
Total $482, 100
-------
CONSULTING DIVISION
TABLE A-5
ESTIMATED CAPITAL COST
1.2.2/1. 1 (250)
5, OOP ppm INITIAL EMISSION LEVEL
500 ppm CONTROL EFFECTIVENESS
Equipment $234, 000
Civil Works 41,500
Buildings -0-
Insulation 26, 100
Pipingand Ductwork 105, 500
Instrumentation 14, 400
Electrical 20, 500
Miscellaneous and Catalyst 43, OOP
Total $485,000
TABLE A-6
ESTIMATED CAPITAL COST
1.2. 2/1.2 (750)
4, OOP ppm INITIAL EMISSION LEVEL
500 ppm CONTROL EFFECTIVENESS
Equipment $465, 000
Civil Works 66, 300
Buildings -0-
Insulation 59, 500
Piping and Ductwork 185,000
Instrumentation 14, 500
Electrical 24, 500
Miscellaneous and Catalyst 105, 200
Total $920,000
-------
CONSULTING DIVISION
TABLE A-7
ESTIMATED CAPITAL COST
1. 2.2/1.2 (1,500)
4, OOP ppm INITIAL EMISSION LEVEL
500 ppm CONTROL EFFECTIVENESS
Equipment $713,000
Civil Works 112,000
Buildings -0-
Insulation 82, 000
Piping and Ductwork 309, 000
Instrumentation 17, 200
Electrical 27. 700
Miscellaneous and Catalyst 189, 100
Total $1,450,000
TABLE A-8
ESTIMATED CAPITAL COST
1.1.1 (750)
NEW DUAL ABSORPTION PLANT
(NO OLEUM PRODUCTION)
Equipment $1,288,000
Civil Works 187, 500
Buildings 18,700
Insulation 89,200
Piping and Ductwork 452, 000
Instrumentation 66, 300
Electrical 107,000
Miscellaneous and Catalyst 291. 300
Total $2,500,000
-------
CONSULTING DIVISION
TABLE A-9
ESTIMATED CAPITAL COST
PROCESS 1.2.3/1.4 (340)
3. 200 ppm INITIAL EMISSION LEVEL
500 ppm CONTROL EFFECTIVENESS
Equipment $393, 000
Civil Works 61,700
Buildings -0-
Insulation 29, 900
Piping and Ductwork 170, 000
Instrumentation 18,400
Electrical 25, 800
Miscellaneous 41, 200
Total $740, 000
TABLE A-10
ESTIMATED CAPITAL COST
PROCESS 2. 1. 1/1. 2 (250)
4, OOP ppm INITIAL EMISSION LEVEL
200 ppm CONTROL EFFECTIVENESS
Equipment - SO Removal $ 22, 700
SO Recovery 264. OOP
Sub Total $286, 700
Civil Works 27, 300
Buildings 97,200
Insulation 51,700
Piping and Ductwork 60,700
Instrumentation 30, 300
Electrical 30, 000
Miscellaneous 6, 100
Total $590,000
-------
Kitt<0*nica/
CONSULTING DIVISION
TABLE A-11
ESTIMATED CAPITAL COST
PROCESS 2.2.6/1.2 (250)
4,000 ppm INITIAL EMISSION LEVEL
200 ppm CONTROL EFFECTIVENESS
Equipment - SC" Removal $ 21,000
SO Recovery 212, 300
Sub Total $233,300
Civil Works 25,000
Buildings 88, 500
Insulation 47, 600
Piping and Ductwork 55, 400
Instrumentation 27,700
Electrical 27,000
Miscellaneous 5, 500
Total $510,000
TABLE A-12
ESTIMATED CAPITAL COST
PROCESS 2. 2. 8/1. 2 (250)
4, OOP ppm INITIAL EMISSION LEVEL
200 ppm CONTROL EFFECTIVENESS
Equipment - SO Removal $ 88,400
SO Recovery 163. OOP
Sub Total $251,400
Civil Works 30,000
Buildings 86, 500
Insulation 41,600
Piping and Ductwork 106, 500
Instrumentation 33,000
Electrical 30, 000
Miscellaneous 6, OOP
Total $585,000
-------
CONSULTING DIVISION
TABLE A-13
ESTIMATED CAPITAL COST
PROCESS 2.2. 14/1.2 (250)
4, OOP ppm INITIAL EMISSION LEVEL
200 ppm CONTROL EFFECTIVENESS
Equipment - SO Removal $166, 000
SO Recovery 67, OOP
Sub Total $233,000
Civil Works 18,600
Buildings 46, 300
Insulation 13, 900
Piping and Ductwork 71, 200
Instrumentation 53, 300
Electrical 23, 100
Miscellaneous 5, 600
Total $465,000
TABLE A-14
ESTIMATED CAPITAL COST
PROCESS 2.2.28/1.2 (250)
4, OOP ppm INITIAL EMISSION LEVEL
500 ppm CONTROL EFFECTIVENESS
Equipment $320, 000
Civil Works 29, 700
Buildings 86, 000
Insulation 17,200
Piping and Ductwork 112, 000
Instrumentation 58, 000
Electrical 38, 000
Miscellaneous 9, 100
Total $670,000
-------
CONSULTING DIVISION
TABLE A-15
ESTIMATED CAPITAL COST
PROCESS 2. 3.3/1.2 (250)
4, OOP ppm INITIAL EMISSION LEVEL
200 ppm CONTROL EFFECTIVENESS
Equipment - SO Removal $ 46, 800
SO^ Recovery 84, 300
Sull Total $131,100
Civil Works 10, 800
Buildings 32,000
Insulation -0-
Piping and Ductwork 50, 800
Instrumentation 15,400
Electrical 38, 500
Miscellaneous 6,400
Total $285,000
TABLE A-16
ESTIMATED CAPITAL COST
PROCESS 2.4. 5/1.2 (250)
4, OOP ppm INITIAL EMISSION LEVEL
200 ppm CONTROL EFFECTIVENESS
Equipment - SO Removal $133,000
SO Recovery 243, OOP
Sub Total $376, 000
Civil Works 13,400
Buildings 53, 700
Insulation 21,500
Piping and Ductwork 95, 500
Instrumentation 40, 300
Electrical 14,700
Miscellaneous 4, 900
Total $620,000
-------
CONSULTING DIVISION
TABLE A-17
ESTIMATED CAPITAL COST
PROCESS 2.4.6/1.2 (250)
4. OOP ppm INITIAL EMISSION LEVEL
200 ppm CONTROL EFFECTIVENESS
Equipment - SO Removal $ 59,000
SO Recovery 271, OOP
Sub Total $330, 000
Civil Works 15,300
Buildings 173, 000
Insulation 21,600
Piping and Ductwork 61, 900
Instrumentation 30, 700
Electrical 46,000
Miscellaneous 11, 500
Total $690,000
-------
TABLE Bl
CONTROL
CLASS
Process
Nominal Capacity
Production Rate
Conversion Rate
Initial Investment
Book Value
Raw Material and Utilities
Sulfur
Elec. Power
Cooling Water
Process Water
B. F. Water
Steam
Operating Expenses
Labor
Supervision
Maintenance (4%)
Overhead @ 70% of Above
Indirect Costs
Depreciation 10%)
Interest 7-1/2% )
Taxes and Insurance (1-1/2%)
Annual Operating Cost
T/Y Acid Production
Production Cost/T
Control Cost/T
COST FOR NEW DUAL ABSORPTION 1. 1. 1
COMPARED TO
2. 2 SINGLE ABSORPTION
1.1.1 (250)
250 T/D
250 T/D
99. 5 %
$1,300, 000
1, 300, 000
$ 677,700
39,400
24, 700
360
5,900
- 59, 800
47, 500
21, 100
52,000
84, 800
227, 000
19, 500
$1, 140, 160
82, 5UU
$ 13.84
.41
ACID PLANTS
1. 1. 1 (750)
750 T/D
750 T/D
99. 5 %
$2, 500, 000
2, 500, 000
$2, 033, 000
118, 000
74, 100
1,080
17, 700
- 179,300
47, 500
21. 100
100,000
118,700
437,000
37, 500
$2,826,380
247, 500
$ 11.43
. 18
1. 1. 1 (1, 500)
1,500 T/D
1, 500 T/D
99. 5 %
$3, 700,000
3, 700, 000
$4, 066, 000
236, 000
148,200
2, 160
35,400
- 359,400
47, 500
21, 100
148,000
152, 000
647, 000
55, 500
$5, 199,460
495,000
$ 10. 50
. 12
-------
TABLE B2
CONTROL COST FOR ADD-ON
DUAL ABSORPTION
1.2. 1
APPLIED TO
CLASSES 1. 1 OR 1.
Process 1.
Initial Emission Level
Nominal Capacity
Production Rate
Conversion Rate
Initial Investment $1,
Book Value
Raw Material and Utilities
Sulfur $
Elec. Power
Cooling Water
Process Water
B.F. Water
Steam
Operating Expenses
Labor
Supervision
Maintenance (4%)
Overhead @ 70% of Above
Indirect Costs
Depreciation 10%)
Interest 7-1/2% )
Taxes and Insurance
(1-1/2%)
Annual Operating Cost $1,
T/Y Acid Production
Production Cost/T $
Control Cost/T
2 ACID PLANTS
2.1/1.1 (250)
5, 000 ppm
250 T/D
261.9 T/D
99. 5 %
615, 000
515^000
710,900
57,800
30,200
350
4,910
54,400
47,500
21, 100
64, 500
93,200
90, 000
24,200
090,260
86,427
12.61
1.44
1.2. 1/1.2 (250)
4, 000 ppm
250 T/D
259. 1 T/D
99. 5 %
$1, 612,800
1, 612,800
$ 703,300
57,600
30,100
340
4,910
- 54,300
47,500
21,100
64, 500
93,200
282, 500
24,200
$1,274,950
85,503
$ 14.91
1.48
-------
TABLE B3
CONTROL COST FOR ADD-ON DUAL ABSORPTION 1. 2. 2
APPLIED TO
CLASS 1. 1 ACID PLANTS AT 5, 000 ppm EMISSION LEVEL
Process
Nominal Capacity
Production Rate
Conversion Rate
Initial Investment
Book Value
Raw Material and
Utilities
Sulfur
Elec. Power
Cooling Water
Process Water
B.F. Water
Steam
Operating Expenses
Labor
Supervision
Maintenance (4%)
Overhead @ 70%
of Above
1.2.2/1. 1 (50)
50 T/D
52.3 T/D
99. 5 %
$ 685,000
260,000
$ 142, 000
11,570
6,040
70
980
- 10,870
47,500
21, 100
27,400
67,200
No Supplementary Production
1. 2.2/1. 1 (250)
250 T/D
261. 9 T/D
99. 5 %
$1, 585,000
485,000
$ 710,900
57,800
30,200
350
4,910
- 54,400
47,500
21, 100
63,400
92,400
1.2.2/1. 1 (750)
750 T/D
785 T/D
99. 5 %
$3, 020, 000
920,000
$2, 110,000
172,700
90. 300
1,020
14, 730
- 163,000
47,500
21, 100
121,000
132,800
With
1.2.2/1. 1 (50)
50 T/D
58 T/D
99. 5 %_
$ 685, 000
260,000
$ 157,700
12,450
6.800
80
1, 150
- 12,850
47,500
21, 100
27.400
67,200
Supplementary Production
1. 2. 2/1. 1 (250) 1.
250 T/D
290.5 T/D
99. 5 %
$1,535,000 $3,
485,000
$ 788,500 $2,
62, 100
33,900
380
5,750
- 64,300
47, 500
21, 100
63.400
92.400
2.2/1. 1 (750)
750 T/D
871 T/D
99. 5 %
020,000
920,000
365,000
186,000
101, 600
1,140
17,260
193,000
47, 500
21, 100
121,000
132, 800
Indirect Costs
Depreciation 10%)
Interest 7-1/2% )
Taxes and Insurance
(1-1/2%)
Annual Operating
Cost
T/Y Acid Production
Production Cost/1
Control Cost/T
45,500
10.270
368,760
17,250
21.35
3.50
84, 800
23.800
$1,082,760
86,427
$ 12.53
1.36
161,000
45.200
$2,754, 350
259,000
$ 10.62
.78
45,500
10.270
$ 384,300
19, 140
$ 20.08
2. 30
84, 800
23.800
$1, 159,330
95,865
$ 12.09
.92
161,000
45.200
$3,006,600
287,430
$ 10.46
. 59
-------
TABLE B4
CONTROL COST FOR ADD-ON DUAL ABSORPTION 1. 2. 2
APPLIED TO
CLASS 1. 2 ACID PLANTS
Without Supplementary Production
With Supplementary Production
Process
Initial Emmission
Level
Nominal Capacity
Production Rate
Conversion Rate
Initial Investment
Book Value
1.2.2/1.2 (250)
4, 000 ppm
250 T/D
259. 1 T/D
99. 5 %
$1, 582, 100
1,582, 100
1.2.2/1.2 (250)
2, 500 ppm
250 T/D
255 T/D
99. 5 %
$1, 580,000
1, 580,000
1.2.2/1.2 (750)
4, 000 ppm
750 T/D
777 T/D
99. 5 %
$3,020,000
3, 020, 000
1.2.2/1.2 (1.500)
4, 000 ppm
1, 500 T/D
1, 554 T/D
99. 5 %
$4,450,000
4, 450, 000
1.2.2/1.2 (250)
4, 000 ppm
250 T/D
288 T/D
99. 5 %
$1, 582, 100
i, 582, 100
1. 2.2/1.2 (750)
4,000 ppm
750 T/D
864 T/D
99. 5 %
$3,020,000
3, 020, 000
1.2. 2/1.2 (1, 500
4, 000 ppm
1, 500 T/D
1, 727 T/D
99. 5 %
$4, 450, 000
4,450,000
Raw Material and
Utilities
Sulfur $ 703,300
Elec. Power 57, 600
Cooling Water 30, 100
Process Water 340
B.F. Water 4,910
Steam - 54,300
Operating Expenses
Labor 47, 500
Supervision 21,100
Maintenance (4%) 63,300
Overhead @ 70%
of Above 92, 300
Indirect Costs
Depreciation 10%)
Interest 7-1/2% ) 277,000
Taxes and Insurance
(1-1/2%) 23,700
Annual Operating
Cost $1,266,850
T/Y Acid Production 85, 503
Production Cost/T $ 14.82
Control Cost/T 1.39
692,000
56, 700
29,700
340
4,830
53,500
47, 500
21, 100
63, 300
92,300
277,000
23.700
$1,254, 970
84, 150
$ 14.91
1.63
$2, 110, 000
173,300
90, 600
1,050
14,720
- 163,000
47, 500
21, 100
121,000
132,800
529,000
45.200
$3, 123, 270
256, 500
$ 12.20
.95
$4,220,000
346, 600
181, 200
2, 100
29, 440
- 326, 000
47, 500
21, 100
178,000
172, 800
778, 000
66. 700
$5,717,440
513,000
$ 11. 14
.76
781,700
62,900
34,000
380
5, 750
64, 300
47,500
21, 100
63, 300
92,300
277,000
23.700
$1, 345,330
95.040
$ 14. 16
.73
$2, 345,000
188, 500
101,700
1, 140
17,260
- 193,000
47, 500
21, 100
121,000
132,800
529,000
45.200
$3, 357,200
285,000
$ 11.76
.51
$4, 690,000
377, 500
204,000
2, 280
34, 500
- 386,000
47, 500
21, 100
178,000
172,800
778,000
66.700
$6, 186,380
570,000
$ 10.86
.48
-------
TABLE B6
CONTROL
CLASS 1
Process
Initial Emission Level
Nominal Capacity
Operating Capacity
Conversion Rate
Initial Investment
Book Value
Raw Material and Utilities
Sulfur
Elec. Power
Cooling Water
Process Water
B.F. Water
Steam
Natural Gas
Na2SO
Na2C03
Oxidation Inhibitor
Operating Expenses
COST FOR PROCESS 2.1.1
APPLIED TO
. 1 and 1.2 ACID PLANTS
2. 1. 1/1. 1 (250)
5, 000 ppm
250 T/D
250 T/D
99. 75 %
$1,730,000
630^000
$ 709,000
55,850
24,700
710
5,770
- 54,300
1,200
- 225,000
180,000
2, 500
Labor 111,000
Supervision 21, 100
Maintenance (4%) 69, 200
Overhead @ 70% of Above 141, 000
Indirect Costs
Depreciation 10%)
Interest 7-1/2% )
Taxes and Insurance
(1-1/2%)
Annual Operating Cost
T/Y Acid Production
Production Cost/T
Control Cost/T
111,000
26,000
$1, 179,730
82,500
$ 14.30
3. 13
2. 1. 1/1.2 (250)
4, 000 ppm
250 T/D
250 T/D
99. 8 %
$1, 691,000
1^691,000
$ 702,700
54,300
24,700
630
5, 770
- 56,300
960
- 180,000
144,000
2,000
111,000
21,100
67,600
140,000
296,000
25,440
$1, 359,900
82,500
$ 16.48
3.05
-------
TABLE B7
CONTROL CO3T (SO,, CONTROL ONLY) FOR PROCESS 2.2. 6
APPLIED TO
Process
Initial Emission
Level
Nominal Capacity
Production Rate
Conversion Rate
Initial Investment
Book Value
Raw Material and
Utilities
Sulfur
S as SO,
Elec. Power
Cooling Water
Process Water
B.F. Water
Steam
Fuel Oil
MgO
Operating Expenses
Labor
Supervision
Maintenance (4%)
Overhead @ 70%
of Above
Indirect Costs
Depreciation 10%)
Interest 7-1/2% )
Taxes & Insurance
(1-1/2%)
Annual Operating
Cost
T/Y Acid
Production
Production Cost/T
Control Cost/T
2.2. 6/1.2 (50)
4, 000 ppm
50 T/D
52 T/D
99. 8 %
$720,000
720, 000
$140, 500
8,600
5,200
70
1, 160
-12,850
5,600
200
94, 300
21, 100
28,800
100, 940
126,000
10.800
$530,420
17, 160
$ 30.91
8. 61
2.2.6/1.2 (250)
4, 000 ppm
250 T/D
260 T/D
99. 8 %
$1, 610,000
1, 610,000
$ 702, 700
42,900
25,300
330
5,770
- 64,200
25,800
990
94, 300
21, 100
64, 300
125,700
282,000
24, 100
$1,353, 790
85,700
$ 15.80
2.37
CLASS
2.2.6/1.2 (250)
2, 000 ppm
250 T/D
256 T/D
99. 9 %
$1, 565,000
1,565,000
$ 693,000
42,700
25,400
330
5,770
- 64,200
17,500
625
94, 300
21, 100
62, 600
124, 600
274,000
23,450
$1,321, 175
84, 500
$
2.35
1. 1, 1. 2 and 1.4 (SMELTER GAS) ACID PLANTS
2.2.6/1.2 (250)
2, 500 ppm
250 T/D
256 T/D
98. 875 %
$1, 570,000
1, 570, 000
$ 692, 000
42, 300
25,400
330
5, 700
- 63,200
17,500
620
94, 300
21, 100
62, 600
124, 700
275,000
23, 500
$1,321,850
84, 500
$ 15.64
2. 36
2.2.6/1.2 (250)
5, 000 ppm
250 T/D
261 T/D
99. 750 %
$1, 650,000
550,000
$ 709, 000
44, 600
26,000
330
5,820
- 64, 800
35,000
1,250
94, 300
21, 100
66,000
127,000
288, 750
24, 700
$1,379,050
86, 500
$ 15.94
2. 38
2.2.6/1. 1 (250)
5, 000 ppm
250 T/D
262 T/D
99. 75 %
$1, 650,000
1,650,000
$ 709,000
44,600
26,000
330
5, 770
- 64,200
35,000
1,250
94,300
21, 100
66,000
127,000
96,200
24,700
$1, 187, 050
86, 500
$ 13.72
2.57
2.2.6/1.4 (250)
3, 200 ppm
250 T/D
257 T/D
99. 84 %
$2,275,000
2, 275,000
$
-0-
48,600
26,000
330
35,000
1,250
141,000
21, 100
91,000
177,300
398,500
34, 100
$ 974, 180
84, 800
$ 11.49
2. 70
2.2. 6/1. 2 (750)
4, 000 ppm
750 T/D
780 T/D
99. 8 %
$2,880,000
2,880,000
$2, 107,000
128, 700
77, 300
990
17, 300
- 192,400
84, 000
2,970
94, 300
21, 100
115,200
161,420
504,000
43.200
$3, 165,080
257,400
$ 12.30
1.05
2. 2.6/1. 2
4,000
1,500
1, 560
99.8
$4,045, 000
4,045, 000
$4,214, 000
257,400
154, 600
1, 980
34, 600
- 384, 800
168,000
5,940
94, 300
21, 100
161,800
194,040
707, 875
60, 675
$5,691, 510
514, 800
$ 11.06
.68
(1,500)
ppm
T/D
T/D
%
-------
TABLE B8
CONTROL COST (SO0,
£i
CLASS 1. 1, 1.2 and
Process
Initial Emission
Level
Nominal Capacity
Production Rate
Conversion Rate
Initial Investment
Book Value
Raw Material and
Utilities
Sulfur
S as SO2
Elec. Power
Cooling Water
Process Water
B.F. Water
Steam
Fuel Oil
MgO
Operating Expenses
Labor
Supervision
Maintenance (4%)
Overhead @ 70%
of Above
Indirect Costs
Depreciation 10%)
Interest 7-1/2% )
2.2. 6/1.
4,000
50
52
99.8
$728,000
728,000
$140,500
10,200
5,200
70
1, 160
-12,850
5,600
200
94,300
21, 100
29, 120
101, 160
127,400
.2 (50) 2.2.6/1.2 (50)
ppm 2, 500 ppm
T/D 50 T/D
T/D 51. 2 T/D
% 99. 875 %
$698,000
698,000
$138,200
10, 100
5, 120
70
1, 140
-12,650
3,500
125
94, 300
21, 100
27,920
100.300
122, 150
2.2. 6/1. 1 (250)
5, 000 ppm
250 T/D
262 T/D
99. 75 %
$1,670,000 $1
570, 000 1
$709,000
52,900
26,000
330
5,770
- 64, 200
35,000
1,250
94,300
21, 100
66, 700
127, 500
99,800
2.2.6/1.2 (250)
2, 500 ppm
250 T/D
256. 1 T/D
99.875 %
,590,000 $1
, 590, 000 1
$691,000
50, 800
25,400
330
5,700
- 63,200
17, 500
620
94,300
21, 100
63, 600
125,300
278,250
SO_ AND MIST) FOR PROCESS 2
APPLIED TO
.2.6
1.4 (SMELTER GAS) ACID PLANTS
2.2. 6/1.2 (250)
4, 000 ppm
250 T/D
260 T/D
99. 8 %
,630,000 $2
,630,000 2
$702,700
51,200
25,800
330
5,770
- 64, 200
28,000
990
94,300
21, 100
65,200
126,400
285,000
2.2. 6/1.4 (250)
3, 200 ppm
250 T/D
257 T/D
99. 84 %
,300,000
,300,000
$
-0-
61,500
26,000
330
35,000
1,250
141,000
21, 100
92,000
178,000
403,000
2.2. 6/1.2 (750) 2
2, 500 ppm
750 T/D
768.3 T/D
99.875 %
$2,800,000 $2,
2,800,000 2.
$2,073,000 $2,
151,500
76,000
980
17, 100
-189.500
52,500
1,860
94, 300
21, 100
112,000
159,200
490,000
.2.6/1.2 (750) 2
4, 000 ppm
750 T/D
780 T/D 1
99. 8 %
919,000 $3,
919,000 3,
107,000 $4,
152, 500
77,300
990
17,300
192,400
84, 000
2, 970
94,300
21, 100
116, 760
162, 500
510,800
.2. 6/1.2 (1500)
2, 500 ppm
1.500 T/D
,536. 5 T/D
99. 875 %
950, 000
950, 000
146,000
303,000
152,200
1,950
34, 100
379,000
105.000
3, 710
94, 300
21, 100
158, 000
191,400
691.250
2.2. 6/1.2 (1500)
4, 000 ppm
1, 500 T/D
1. 560 T/D
99. 8 %
$4. 104,000
4, 104,000
$4,214,000
305,000
154, 600
1,980
34, 600
-384,800
168,000
5,940
94,300
21, 100
164,200
195,720
718,200
Taxes & Insurance
(1-1/2%)
Annual Operating
Cost
T/Y Acid
Production
Production Cost/T
Control Cost/T
10, 920
$534,080
17, 160
$ 31. 12
8.82
10.470
$521,845
16,900
$ 30.88
8.70
25. 100
$1,200,550 $1
86,500
$ 13.88
2.71
23.850
,334,550 $1
84, 513
$ 15.79
2.51
24.500
,367,090
85,700
$ 15.95
2.51
34. 500
$993, 680
84, 800
$ 11.72
2.92
42.000
$3, 102,040 $3,
253, 540
$ 12.23 $
1.15
43.800
198,920 $5,
257,400
12.43 $
1. 18
59.250
582,260
507,045
11.01
.78
61. 560
$5,754,400
514,800
$ 11.18
.80
-------
TABLE B9
CONTROL COST FOR PROCESS 2. 2. 8
CLASS 1.
Process
Initial Emission Level
Nominal Capacity
Production Rate
Conversion Rate
Initial Investment
Book Value
Raw Material and Utilities
Sulfur
S as SO2
Elec. Power
Cooling Water
Process Water
B.F. Water
Steam
K2C03
Oxidation Inhibitor
Operating Expenses
Labor
Supervision
Maintenance (4%)
Overhead @ 70% of Above
Indirect Costs
Depreciation 10%)
Interest 7-1/2% )
Taxes and Insurance (1-1/2%)
Annual Operating Cost
T/Y Acid Production
Production Cost/1
Control Cost/T
APPLIED TO
1, 1.2 and 1.4 (SMELTER
2.2.8/1. 1 (250)
5, 000 ppm
250 T/D
262 T/D
99.75 %
$1,710,000
610,000
$ 709, 000
56, 330
25, 300
500
5, 770
- 47, 700
14, 300
2, 960
95, 000
21, 100
68, 300
129,200
106,800
25,600
$1, 212,460
86,500
$ 14.02
2. 84
GAS) ACID PLANTS
2.. 2. 8/1. 2 (250)
4, 000 ppm
250 T/D
260 T/D
99. 8 %
$1, 685, 000
1, 685, 000
$ 702, 700
55, 750
25,200
600
5, 770
- 51,000
11,400
2,360
95, 000
21, 100
67, 300
128,400
295,000
25,300
$1, 384,880
85,700
$ 16. 16
2. 73
2. 2. 8/1.4 (250)
3, 200 ppm
250 T/D
257 T/D
99. 84 %
$2, 340,000
2^340, 000
$
-0-
64, 900
25,300
500
5,770
- 47, 700
14, 300
2,960
141, 000
21,100
93, 500
179,000
410,000
35, 100
$ 945, 730
84,800
$ 11, 15
2. 25
-------
TABLE BIO
CONTROL COST FOR PROCESS
Process
Initial Emission
Level
Nominal Capacity
Production Rate
Conversion Rate
Initial Investment
Book Value
Raw Material and
Utilities
Sulfur
S as SO2
Elec. Power
Cooling Water
Process Water
B. F. Water
Steam
Methylamine
Antioxidant
Operating Expenses
Labor
Supervision
Maintenance (4%)
Overhead @ 70%
of Above
Indirect Costs
Depreciation 10%)
Interest 7-1/2% )
Taxes and Insurance
(1-1/2%)
Annual Operating
Cost
T/Y Acid Production
Production Cost/T
Control Cost/T
2.2. 14/1.2 (50)
4, 000 ppm
50 T/D
52 T/D
99. 8 %
$ 695,000
695,000
$ 140,500
11,500
5,300
80
1, 150
9,350
1,900
120
71,200
21, 100
27,800
84,000
121,500
10.400
$ 487,200
17, 160
$ 28.39
6. 10
CLASS 1. 1, 1.2
2.2. 14/1. 1 (250)
5, 000 ppm
250 T/D
262 T/D
99. 75 %
$1, 575,000
475J500
$ 709,000
57,250
26, 900
380
5, 770
- 42,400
11, 900
750
71,200
21, 100
62,900
108, 500
83,000
23. 600
$1, 139,850
86, 500
$ 13. 18
1. 98
APPLIED TO
and 1.4 (SMELTER GAS)
2.2. 14/1. 2 (250)
4, 000 ppm
250 T/D
260 T/D
99. 8 %
$1,565,000
1, 565, 000
$ 702, 700
57,200
26,460
370
5. 770
- 46, 750
9,500
600
71,200
21, 100
62, 700
108, 500
274,000
23, 500
$1,316, 850
85, 700
$ 15. 37
1.88
2.2. 14
ACID PLANTS
2.2. 14/1.4 (250)
3, 200 ppm
250 T/D
257 T/D
99. 84 %
$2,235,000
2,235,000
$
-0-
72,900
50, 100
380
21,800
11,900
750
111,500
21, 100
89, 400
160,500
391,500
33, 600
$ 965,430
84, 800
$ 11.38
2.58
2.2. 14/1.2 (750)
4, 000 ppm
750 T/D
780 T/D
99. 8 %
$2,865, 000
2,865,000
$2, 107,000
172,000
79,300
1, 100
17, 300
- 140, 000
28, 500
1,800
71,200
21, 100
115, 600
145,000
501, 000
43,000
$3, 163, 900
257,400
$ 12.29
1. 03
2. 2. 14/1.2 (1,500)
4, 000 ppm
1, 500 T/D
1,560 T/D
99. 8 %
$4, 080, 000
4, 080,000
$4, 214,000
344, 000
159,000
2,200
34, 600
- 280,000
57,000
3,600
71,200
21, 100
163,500
179,000
715,000
61,200
$5,745,400
514, 800
$ 11.16
.78
-------
TABLE B-ll
CONTROL COST FOR PROCESS 2. 2. 22
APPLIED TO
CLASS 1. 2 ACID PLANT
Process 2.2.22/1.2 (396)
Initial Emission Level 1, 800 ppm
Nominal Capacity 396 ST/D
Production Rate 402 ST/D
Conversion Rate 99. 82 %
Initial Investment $1, 800, 000
Book Value 1.800,000
Raw Material and Utilities
Sulfur $1,105,000
Elec. Power 74, 900
Cooling Water 39,500
Process Water 1, 130
B.F. Water 9,250
Steam - 77,400
Operating Expenses
Labor 71,100
Supervision 21, 100
Maintenance (4%) 72, 000
Overhead @ 70% of Above 115, 000
Interest 7-1/2% ) 315'°°°
Indirect Costs
Depreciation 10%)
Interest 7-1/2% )
Taxes and Insurance (1-1/2%) 27, OOP
Annual Operating Cost $1,773,580
T/Y Acid Production 132, 800
Production Cost/T $ 13.35
Control Cost/T 1.00
NOTE:
No information was available to determine control cost at conditions
for which other processes were rated.
1, 800 ppm would be an unusually low emission level for most U.S.
plants.
-------
TABLE B12
CONTROL COST FOR PROCESS 2.2.28
Process
Initial Emission Level
Nominal Capacity
Production Rate
Conversion Rate
Initial Investment
Book Value
Raw Material and Utilities
Sulfur
S as SO2
Elec. Power
Cooling Water
Process Water
B.F. Water
Steam
By-Product (Waste)
A12(S04)3
CaSO4
CaCOS
Operating Expenses
Labor
Supervision
Maintenance (4%)
Overhead @ 70% of Above
Indirect Costs
Depreciation 10%)
Interest 7-1/2% )
Taxes and Insurance (1-1/2%)
Annual Operating Cost
T/Y Acid Production
Production Cost /T
Control Cost/T
APPLIED TO
CLASS 1. 1 and 1.2 ACID
2.2.28/1. 1 (250)
5, 000 ppm
250 T/D
262 T/D
99. 5 %
$1,770,000
670J)00
$ 709, 000
44, 000
34, 700
480
5, 770
- 57, 100
1,400
2,200
1, 600
7,500
94, 300
21, 100
70, 700
130,300
117,200
26, 500
$1,209,650
86,400
$ 14.00
2.87
PLANTS
2.2. 28/1. 1 (250)
5, 000 ppm
250 T/D
263 T/D
99. 75 %
$1,800,000
700,000
$ 709,000
44, 000
34, 700
480
5,770
- 57, 100
1,400
2,200
1,600
7,500
94, 300
21, 100
72, 000
131,300
122, 500
27,000
$1,217,750
86,800
$ 14. 03
2. 91
2.2.28/1.2 (250)
4,000
250
260
99.8
$1,800,000
1, 800,000
$ 705,700
44,000
34,700
480
5,770
- 57, 100
1,400
2,200
1,600
7,500
94,300
21, 100
72,000
131,300
315,000
27,000
$1,406,950
85,800
$ 16.40
2.96
ppm
T/D
T/D
%
-------
TABLE B13
CONTROL COST FOR PROCESS 2. 2. 29
APPLIED TO
Process
Initial Emission Level
Nominal Capacity
Production Rate
Conversion Rate
Initial Investment
Book Value
Raw Material and
Utilities
Sulfur
Elec. Power
Cooling Water
Process Water
B.F. Water
Steam
Resin
Alkali
Operating Expenses
Labor
Supervision
Maintenance (4%)
2.2.29/1.2 (50)
4, 000 ppm
50 T/D
52. 1 T/D
100 %
$ 620,000
620^000
$ 140,400
10,700
7,250
70
1, 150
- 11,070
2,500
250
63,300
21, 100
24,800
CLASS 1. 1 and CLASS
2.2.29/1. 1 (250)
5, 000 ppm
250 T/D
262 T/D
100 %
$1,495,000
395,000
$ 705,000
53, 600
36, 300
350
5,770
- 55,400
12,500
1,250
63,300
21, 100
59,800
1.2 ACID PLANTS
2.2.29. 1.2 (250)
4, 000 ppm
250 T/D
261 T/D
100 %
$1,542,000
1, 542, 000
$ 702,000
53, 600
36,300
350
5, 770
- 55,400
12, 500
1,250
63,300
21, 100
61, 700
2.2.29/1.2 (750)
4, 000 ppm
750 T/D
781 T/D
100 %
$2,970,000
2, 970, 000
$2, 105,000
161,000
108,800
1,050
17, 300
- 166,400
37, 500
3,750
63,300
21, 100
119,000
2.2.29/1.2 (1, 500)
4, 000 ppm
1, 500 T/D
1,562 T/D
100 %
$4,312,000
4,312,000
$4,210,000
322,000
217, 600
2, 100
34, 600
- 332,800
75,000
7, 500
63,300
21, 100
181, 600
Overhead @ 70%
of Above
Indirect Costs
Depreciation 10%)
Interest 7-1/2% )
Taxes and Insurance
(1-1/2%)
Annual Operating Cost
T/Y Acid Production
Production Cost/1
Control Cost/T
76,500
108,500
9.300
$ 454,750
17,200
$ 26.44
4. 15
101,000
69, 100
22.400
$1,096,070
86, 500
$ 12.67
1.50
102,400
270, 000
23.200
$1,298,070
86,200
$ 15.06
1. 63
142, 500
520, 000
45. 500
$3,179,400
258,000
$ 12.32
1.08
172,300
755, 000
64. 700
$5,794,000
515,500
$ 11.24
.86
-------
TABLE B14
CONTROL COST FOR PROCESS 2. 3. 3
APPLIED TO
CLASS 1. 1, 1.2
Process
Initial Emission
Level
Nominal Capacity
Production Rate
Conversion Rate
Initial Investment
Book Value
Raw Material and
Utilities
Sulfur
S as S02
Elec. Power
Cooling Water
Process Water
B.F. Water
Steam
CaSO4 CWaste)
CaO
Operating Expenses
Labor
Supervision
Maintenance (4%)
Overhead @ 70%
of Above
Indirect Costs
Depreciation 10%)
Interest 7-1/2% )
Taxes and Insurance
(1-1/2%)
Annual Operating
Cost
T/Y Acid Production
Production Cost/1
Control Cost/1
2.3. 3/1.2 (50)
4
$ 60S
605
$ 140
10
4
1
- 12
2
7
71
21
24
81
106
9
$ 467
16
, 000 ppm
50 T/D
50 T/D
96 %
,000
,000
,500
,000
,950
70
, 150
,840
,780
,420
,200
, 100
,200
, 500
,000
,070
, 100
,500
$ 28.31
6.00
2.3. 3/1. 1 (250)
5,
$1,395,
295,
$ 709,
50,
24,
5,
- 64,
17,
46,
71,
21,
55,
103,
51.
21,
$1, 113,
82,
$ 13
2
000 ppm
250 T/D
250 T/D
95 %
000
000
000
000
700
360
770
200
500
400
200
100
800
700
600
000
930
500
.50
. 33
and 1.4 (SMELTER GAS) ACID PLANTS
2.3.3/1.2 (250)
4,
$1,385,
1,385,
$ 702,
50,
24,
5,
- 64,
13,
37,
71,
21,
55,
103,
242,
20,
$1,285,
82,
$ 15
2
000 ppm
250 T/D
250 T/D
96 %
000
000
700
700
700
360
770
200
900
100
200
100
400
400
400
800
330
500
.58
. 14
2.3.3/1.4 (250)
3,200 ppm
250 T/D
250 T/D
96. 8 %
$2,010,000
2,010,000
$
-0-
62, 100
47, 900
360
17,500
46,400
, 500
21, 100
80,400
153,900
352,000
30,200
$ 930,360
82,500
$ 11.28
2.48
2.3.3/1.2 (750)
4,
$2,525,
2,525,
$2, 105,
150,
74,
1,
18,
- 192,
41,
HI,
71,
21,
101,
135,
442,
37,
$3, 117,
247,
$ 12
1
000 ppm
750 T/D
750 T/D
96 %
000
000
000
300
000
080
300
500
700
300
200
100
000
400
000
900
780
500
. 60
.33
2. 3. 3/1.2
4, 000
1,500
1,500
96
$3,570,000
3,570,000
$4, 110,000
300, 600
148,000
2, 160
36, 600
- 385,000
83,400
222,600
71,200
21, 100
143,000
164,800
624..500
53. 500
$5,596,460
495, 000
$ 11.31
. 94
(1, 500)
ppm
T/D
T/D
%
-------
TABLE B15
CONTROL COST FOR PROCESS 2.4. 5
CLASS 1.
Process
Initial Emission Level
Nominal Capacity
Production Rate
Conversion Rate
Initial Investment
Book Value
Raw Material and Utilities
Sulfur
S as SO2
Elec. Power
Cooling Water
Process Water
B. F. Water
Steam
Ammonium Nitrate Solution
Ammonia
HN03 (100%)
Oxidation Inhibitor
Operating Expenses
Labor
Supervision
Maintenance (4%)
Overhead @ 70% of Above
Indirect Costs
Depreciation 10%)
Interest 7-1/2% )
Taxes and Insurance (1-1/2%)
Annual Operating Cost
T/Y Acid Production
Production Cost/T
Control Cost/T
APPLIED TO
1, 1.2 and 1.4 (SMELTER
2.4. 5/1. 1 (250)
5, 000 ppm
250 T/D
256. 5 T/D
99. 5 %
$1,750, 000
650^000
$ 709,000
52,000
25,400
520
5, 770
- 59,400
- 222,800
59,200
135, 100
6, 200
95,000
21, 100
70, 000
130, 500
114, 000
26,250
$1, 167, 840
84, 600
$ 13.80
2.63
GAS) ACID PLANTS
2.4. 5/1.2 (250)
4, 000 ppm
250 T/D
255 T/D
. 99. 6 %
$1, 720,000
1,720,000
$ 702, 700
51, 600
25,400
520
5,770
- 60,400
- 186,000
46, 500
108,200
5, 100
95,000
21, 100
68, 700
129,200
301,000
25,800
$1,340, 190
84, 100
$ 15.94
2. 52
2.4. 5/1. 4 (250)
3,200 ppm
250 T/D
256.5 T/D
99. 68 %
$2,400,000
2, 400, 000
$ ---
64, 500
47, 900
520
5,000
- 222,800
59,200
135, 100
6,200
142,500
21, 100
96,000
181, 700
420,000
36,000
$ 992, 920
83, 800
$ 11.85
3.05
-------
TABLE B16
CONTROL COST FOR PROCESS 2. 4. 6
CLASS 1.
Process
Initial Emission Level
Nominal Capacity
Production Rate
Conversion Rate
Initial Investment
Book Value
Raw Material and Utilities
Sulfur
S as SO2
Elec. Power
Cooling Water
Process Water
B.F. Water
Steam
Natural Gas
CaSO4. 1/2H2O
MnSO4
Lime
Operating Expenses
Labor
Supervision
Maintenance (4%)
Overhead @ 70% of Above
Indirect Costs
Depreciation 10%)
Interest 7-1/2% )
Taxes and Insurance (1-1/2%)
Annual Operating Cost
T/Y Acid Production
Production Cost/T
Control Cost/T
APPLIED TO
1, 1.2 and 1.4 (SMELTER
2.4. 6/1. 1 (250)
5, 000 ppm
250 T/D
256. 5 T/D
99. 5 %
$1,850, 000
750, 000
$ 709, 000
53, 850
24, 750
330
5, 770
- 62,900
1, 600
- 18, 600
5,750
11,430
111,000
21, 100
74, 000
144, 300
131, 000
27, 770
$1,240, 150
84,600
$ 14. 66
3. 50
GAS) ACID PLANTS
2.4. 6/1. 2 (250)
4, 000 ppm
250 T/D
255 T/D
99. 6 %
$1,790,000
1^790^000
$ 702, 700
53,850
24,730
330
5, 770
- 62, 100
1,270
- 14, 850
4,700
9, 150
111,000
21, 100
71, 500
142, 500
313,000
26, 850
$1,411,500
84, 200
$ 16.76
3. 33
2.4. 6/1.4
3.200
250
256. 5
99. 68
$2,470,000
2,470,000
$
-0-
65,900
47,950
330
2, 610
1, 600
- 18,600
5,750
11,430
156, 500
21, 100
98, 700
193, 500
433, 000
37, 100
$1,051,650
83, 700
$ 12.56
3. 76
(250)
ppm
T/D
T/D
%
-------
TABLE B17
ACID MIST CONTROL COST FOR DUAL MIST PAD SYSTEM 3. 1. 1
APPLIED TO
CLASSES 1. 1, 1.2, 2.2 and 1.4 (SMELTER
Mist Reduction from 20 to 2 Me/SCF for Non -Oleum Plants
Process
Nominal Capacity
Production Rate
Conversion Rate
Initial Investment
Book Value
Raw Material and
Utilities
Sulfur
S as SO2
Elec. Power
Cooling Water
Process Water
B. F. Water
Steam
Operating Expenses
Labor
Supervision
Maintenance (4%)
Overhead @ 70%
of Above
3. 1. 1/1.2 (250)
250 T/D
250.49 T/D
96 %
$1, 125,000
1, 125,000
$ 702,700
40, 000
24,700
330
5,770
- 64, 200
47,500
21, 100
45,000
79, 520
3. 1. 1/2.2 (250)
250 T/D
250.49 T/D
96 %
$1, 120,000
1, 120,000
$ 702,700
40,000
24,700
330
5,770
- 64, 200
47,500
21, 100
44, 800
79, 380
3. 1. 1/1. 1 (250)
250 T/D
250.49 T/D
95 %
$1, 125,000
25,000
$ 709,000
40,000
24,700
330
5, 770
- 64,200
47,500
21, 100
45,000
79,520
3. 1. 1/1.4 (250)
250 T/D
250.75 T/D
96. 8 %
$1,727, 000
1,727,000
$
47,000
47, 900
330
94,300
21,100
69,080
129, 140
GAS) PLANTS
Mist Reduction from 50 to
3. 1. 1/1.2 (250)
250 T/D
251.2 T/D
96%
$1,225,000
1,225,000
$ 702, 700
40, 000
24, 700
330
5, 770
- 64, 200
47,500
21, 100
49, 000
82,300
3. 1. 1/2.2 (250)
250 T/D
251.2 T/D
96 %
$1,220,000
1JJ20, 000
$ 702,700
40, 000
24,700
330
5,770
- 64,200
47,500
21, 100
48,800
82,200
5 Mg/SCF for Oleum Plants
3. 1. 1/1. 1 (250)
250 T/D
251. 2 T/D
95 %
$1,225,000
25JWO
$ 709, 000
40, 000
24, 700
330
5, 770
- 64,200
47, 500
21, 100
49,000
82, 300
3. 1. 1/1.4 (250)
250 T/D
251.9 T/D
96. 8 %
$1, 827,000
1,827,000
$
47,000
47,900
330
94, 300
21, 100
73,100
131,900
Indirect Costs
Depreciation 10%)
Interest 7-1/2% )
Taxes & Insurance
(1-1/2%)
Annual Operating
Cost
T/Y Acid Production
Production Cost/T
Control Cost/T
196, 875
16.875
, 116, 170
82, 660
13.50
.07
196,000
16.800
$1, 114,880
82, 660
$ 13.49
.06
4,375
16.875
929,970
82.660
11.25
.08
302,225
25.905
736,980
82,747
8.91
. 11
214,700
18.400
$1, 142,300
82,900
$ 13.78
.04
213,500
18.300
$1, 140,700
82,900
$ 13.76
.02
4, 375
18.400
938,275
82, 900
11.32
.06
319,000
27.400
$ 762,030
83, 127
$ 9. 17
.05
-------
TABLE B18
ACID MIST CONTROL COST FOR SYSTEM 3. 1. 2
CLASSES 1 1
APPLIED TO
L, 1.2, 2.2. 1.4 and 2.4 (SMELTER GAS) PLANTS
Mist Reduction from 50 Mg/SCF to
Process
Nominal Capacity
Production Rate
Conversion Rate
Initial Investment
Book Value
Raw Material and
Utilities
Sulfur
S as SOj
Elec. Power
Cooling Water
Process Water
B.F. Water
Steam
Operating Expenses
Labor
Supervision
Maintenance (4%)
Overhead @ 70%
of Above
3. 1.2/1. 1 (250)
250 T/D
250.52 T/D
95 %
$1,200,000
100, 000
$ 709,000
41,700
24,700
330
5,770
- 64, 200
47,500
21, 100
48, 000
81, 600
Mist Reduction from
3. 1.2/1. 2 (250)
250 T/D
250.52 T/D
96 %
$1,200,000
1.200.000
$ 702,700
41,700
24, 700
330
5,770
- 64, 200
47,500
21, 100
48, 000
81,600
20 to 0.3 Mg/SCF from Non -Oleum Plants
3. 1.2/2.2 (250)
250 T/D
250.52 T/D
96 %
$1, 170, 000
1, 170.000
$ 702,700
40, 300
24, 700
330
5,770
- 64, 200
47, 500
21, 100
46, 800
80, 800
3. 1.2/1.4 (250)
250 T/D
250.82 T/D
96. 8 %
$1,827,000
1,827,000
$
49, 600
47,900
330
94, 300
21, 100
73,000
132, 100
3. 1.2/2.4 (250)
250 T/D
250.82 T/D
96. 8 %
$1,790,000
1, 790, 000
$
47,400
47, 900
330
94, 300
21, 100
71,600
131, 000
0. 3 Mg/SCF for Oleum Plants
3. 1.2/1.2 (250)
250 T/D
251. 3 T/D
96 %
$1,300,000
1,300.000
$ 702,700
41, 700
24,700
330
5,770
- 64,200
47, 500
21, 100
52,000
84, 400
3. 1.2/2.2 (250)
250 T/D
251. 3 T/D
96 %
$1.270,000
1,270,000
$ 702,700
40, 300
24, 700
330
5,770
- 64,200
47, 500
21, 100
50, 800
83, 600
Indirect Costs
Depreciation 10%)
Interest 7-1/2% )
Taxes & Insurance
(1-1/2%)
Annual Operating
Cost
T/Y Acid Production
Production Cost/T
Control Cost/T
17, 500
18, 000
$ 951,000
82, 670
$ 11.50
.33
210,000
18.000
$1,137,200
82, 670
$ 13.76
.33
204,750
17. 550
$1, 128, 100
82, 670
$ 13.65
.22
320,000
27.400
765,730
82,770
9.25
.45
313,500
26. 800
753,930
82, 770
9.11
.31
227, 500
19. 500
$1, 163,000
82,940
$ 14.02
.28
222, 500
19.050
$1,154,150
82, 940
$ 13.92
.18
-------
TABLE B19
ACID MIST CONTROL COST FOR SYSTEM 3. 1. 3
APPLIED TO
CLASSES 1.1, 1.2. 2.2, 1. 4 and 2. 4 (SMELTER GAS) ACID PLANTS
Mist Reduction from
Process
Nominal Capacity
Production Rate
Conversion Rate
Initial Investment
Book Value
Raw Material and
Utilities
Sulfur
S as SO2
Elec. Power
Cooling Water
Process Water
B. F. Water
Steam
Operating Expenses
Labor
Supervision
Maintenance (4%)
Overhead @ 70%
of Above
3. 1.3/1. 1 (250)
250 T/D
250.51 T/D
95 %
$1. 144,000
44. 000
&709, 000
40. 700
24. 700
330
5,770
- 64,200
47, 500
21,100
45, 700
80, 000
3. 1.3/1.2 (250)
250 T/D
250.51 T/D
96 %
$1, 144,000
1^ 144, 000
$702. 700
40. 700
24. 700
330
5.770
- 64. 200
47, 500
21.100
45. 700
80, 000
20 to 0. 5 Me/SCF for Non -Oleum Plants
3. 1.3/2.2
250
250.51
96
$1, 123,000
1, 123,000
$702,700
39, 400
24, 700
330
5,770
- 64. 200
47. 500
21, 100
45, 000
79, 500
(250) 3.1.3/1.4(250)
T/D 250 T/D
T/D 250.81 T/D
% 96. 8 %
$1.764,000
1.764.000
$
48, 100
47, 900
330
94, 300
21, 100
70, 600
130,000
3. 1.3/2.4 (250)
250 T/D
250.81 T/D
96. 8 %
$1,732,000
1.732.000
$
45, 900
47, 900
330
94, 300
21, 100
69. 300
129,200
Mist Reduction from
3. 1.3/1.2 (250)
250 T/D
251. 3 T/D
96% L
$1,244,000
1,244.000
$702, 700
40, 700
24, 700
330
5,770
- 64, 200
47,500
21, 100
49, 700
82,800
3. 1.3/2.2
250
251.3
— 96
$1,223,000
1,223,000
$702, 700
39,400
24,700
330
5,770
- 64,200
47. 500
21. 100
49,000
82, 300
50 to 0. 5 Mg/SCF for Oleum Plants
(250) 3.1.3/1.4(250)
T/D 250 T/D
T/D 252. 1 T/D
% -• - ' 98. 8 %
$1,864,000
1. 864. 000
$
48. 100
47, 900
330
94. 300
21. 100
74, 600
132,800
3. 1.3/2.
250
252. 1
96.8
$1,832,000
1,832,000
$
45, 900
47, 900
360
94.300
21, 100
73, 300
132, 000
4 (250
T/D
T/D
%
Indirect Costs
Depreciation 10%)
Interest 7-1/2% )
Taxes & Insurance
(1-1/2%)
Annual Operating
Cost
7,700
17, 150
$935,450
T/Y Acid Production 82, 668
Production Cost/T $ 11.32
Control Cost/T . 15
200. 500
17. 150
$1,121,950
82, 668
$ 13.57
. 13
196, 700
16.870
$1. 115,370
82. 668
$ 13.49
.05
$747,280
82,767
$ 9.03
.23
$737,030
82, 767
$ 8.90
. 10
218,000
18. 650
SI. 147,750
82, 930
$ 13.84
. 10
214,200
18. 370
$1, 141, 170
82, 930
$ 13.76
.02
$773, 080
83.190
$ 9.29
. 17
$ 762. 830
83. 190
$ 9. 17
.05
-------
TABLE B-20
ACID MIST CONTROL COST
APPLIED
FOR PROCESS 3.2. 1
TO
CLASS 1. 1, 1. 2 and 1. 4 (SMELTER GAS) ACID PLANTS
FOR MIST CONTROL TO
0. 5 me/SCF FOR
NEW OR EXISTING OLEUM OR NON-OLEUM PRODUCING PLANTS
Process
Nominal Capacity
Production Rate
Conversion Rate
Initial Investment
Book Value
Raw Material and
Utilities
Sulfur
S as SO2
Elec. Power
Cooling Water
Process Water
B.F. Water
Steam
Operating Expenses
Labor
Supervision
Maintenance (4%)
Overhead @ 70%
of Above
Indirect Costs
Depreciation 10% )
Interest 7-1/2% )
Taxes and Insurance
(1-1/2%)
Annual Operating Cost
T/Y AcidProduction
Production Cost/T
Control Cost/T
3.2.1/1,
50
50. 1
96
$485, 000
485,000
$140,500
9,800
5,000
70
1, 150
-12,800
47,500
21,100
19,400
61,600
85,000
7.300
$385, 620
16,530
$ 23.35
1.05
.2 (50) 3.2. 1/1. 1 (250)
T/D 250 T/D
T/D ' 250. 5 T/D
% 95 %
$1, 185,000
85,000
$ 709,000
41,700
24, 700
330
5, 770
- 64, 200
47,500
21, 100
47, 400
81,200
11,450
17,800
$ 943, 750
82, 670
$ 11.43
.26
3.2. 1/1.2 (250) 3.
250 T/D
250. 5 T/D
96 %
$1,185,000 $1,
1,185,000 1,
$ 702, 700 $
41, 600
24,700
330
5, 770
- 64, 200
47,500
21, 100
47,400
81,200
207,000
17,800
$1,132,900 $
82, 670
$ 13.68 $
.25
2. 1/1.4 (250)
250 T/D
250. 5 T/D
96. 8 %
790,000
790, 000
47,400
47, 900
330
94,300
21, 100
71,700
131,000
314,000
26,900
754, 630
82, 670
9. 13
.33
3. 2. 1/1. 2 (750)
750 T/D
751. 5 T/D
96 %
$2,205,000
2, 205, 000
$2, 107,000
117, 600
74, 100
990
17,300
- 192, 500
47, 500
21, 100
88, 000
110, 000
386,000
33, 100
$2,810, 190
248, 000
$ 11.30
.22
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TABLE B21
ACID MIST CONTROL COST FOR SYSTEM 3. 3. 1
APPLIED TO
CLASS 1. 2 ACID PLANT
Process 3.3. 1/2. 1 (250)
Nominal Capacity 250 T/D
Production Rate 250. 49 T/D
Conversion Rate 96 %
Initial Investment $1, 170, 000
Book Value 1, 170. OOP
Raw Material and Utilities
Sulfur $ 702, 700
S as SO
Elec. Power 47, 500
Cooling Water 24, 700
Process Water 330
B.F. Water 5, 770
Steam - 64,200
Ca(OH) 3,800
CaSO fwaste) 880
Operating Expenses
Labor 47,500
Supervision 21, 100
Maintenance (4%) 46, 700
Overhead @ 70% of Above 80, 700
Indirect Costs
Depreciation 10%)
Interest 7-1/2% )
Taxes and Insurance (1-1/2%) 17, 550
Annual Operating Cost $1, 140, 030
T/Y Acid Production 82, 660
Production Cost/T $ 13.79
Control Cost/T . 36
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