DRAFT GUIDELINE  DOCUMENT:
CONTROL OF FLUORIDE EMISSIONS
          FROM EXISTING
 PHOSPHATE  FERTILIZER PLANTS
        U.S. ENVIRONMENTAL PROTECTION AGENCY
         Office of Air and Waste Management
       Office of Air Quality Planning and Standards
       Research Triangle Park, North Carolina 27711

-------
     DRAFT GUIDELINE DOCUMENT:
  CONTROL OF FLUORIDE EMISSIONS

             FROM  EXISTING
   PHOSPHATE FERTILIZER PLANTS
                   NOTICE

    This draft guideline is now being published for'
comment.  A final guideline will be published after
consideration of these comments.
   UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
   Office of Air Quality Planning and Standards
   Emission Standards and Engineering Division
   Research Triangle Park, North Carolina  27711
          Telephone:  (919) 688-8146
                April 1976

-------
                          CONTENTS

1.   INTRODUCTION  AND SUMMARY                                     1-1
    1.1   INTRODUCTION                                           1-1
    1.2   HEALTH EFFECTS  OF FLUORIDES                             1-5
    1.3   FLUORIDES AND THEIR  CONTROL                             1-6
    1.4   EMISSION GUIDELINES                                     1-7
    1.5   COMPLIANCE TIMES                                       1-10
    1.6   ASSESSMENTS                                            1-11
         1.6.1  Economic                                        1-11
         1.6.2  Environmental                                    1-15
         1.6.3  Energy                                          1-16
    1.7   REFERENCES                                             1-17
2.   HEALTH AND WELFARE EFFECTS  OF FLUORIDES                      2-1
    2.1   INTRODUCTION                                           2-1
    2.2   EFFECT OF FLUORIDES  ON HUMAN  HEALTH                     2-3
         2.2.1  Atmospheric Fluorides                            2-3
         2.2.2  Ingested Fluorides                               2-3
    2.3   EFFECT OF FLUORIDES  ON ANIMALS                          2-5
    2.4   EFFECT OF ATMOSPHERIC  FLUORIDES  ON                      2-6
         VEGETATION
    2.5   EFFECT OF ATMOSPHERIC  FLUORIDES  ON                      2-7
         MATERIALS OF CONSTRUCTION
         2.5.1   Etching  of Glass                                2-7
         2.5.2  Effects  of Fluorides on Structures              2-9
    2.6   RATIONALE                                              2-10
    2.7   REFERENCES                                             2-10

-------
                                                                Page
3.  PHOSPHATE FERTILIZER INDUSTRY ECONOMIC PROFILE AND          3-1
    STATISTICS
    3.1  INDUSTRY STRUCTURE                                     3-1
    3.2  EXISTING PLANTS                                        3-4
    3.3  CAPACITY UTILIZATION                                   3-18
    3.4  CONSUMPTION PATTERNS                                   3-20
    3.5  FUTURE TRENDS                                          3-25
    3.6  PRICES                                                 3-29
    3.7  WORLD STATISTICS ON P00C                               3-33
                              i b
    3.8  REFERENCES                                             3-36
4.  PHOSPHATE FERTILIZER PROCESSES                              4-1
    4.1  INTRODUCTION                                           4-1
    4.2  WET-PROCESS PHOSPHORIC ACID MANUFACTURE                4-3
    4.3  SUPERPHOSPHORIC ACID MANUFACTURE                       4-11
    4.4  DIAMMONIUM PHOSPHATE MANUFACTURE                       4-17
    4.5  TRIPLE SUPERPHOSPHATE MANUFACTURE AND STORAGE          4-21
         4.5.1  Run-of-Pile Triple Superphosphate               4-21
                Manufacture and Storage
         4.5.2  Granular Triple Superphosphate                  4-24
                Manufacture and Storage
    4.6  REFERENCES                                             4-29
5.  EMISSIONS                                                   5-1
    5.1  NATURE OF EMISSIONS                                    5-1
    5.2  UNCONTROLLED FLUORIDE EMISSIONS                        5-3
         5.2.1  Emissions from Wet-Process Phosphoric           5-3
                Acid Manufacture
         5.2.2  Emissions from Superphosphoric Acid             5-7
                Manufacture
                            ii

-------
                                                                Page
         5.2.3  Emissions from Diammonium Phosphate             5-8
                Manufacture
         5.2.4  Emissions from Triple Superphosphate            5-10
                Manufacture and Storage
    5.3  TYPICAL CONTROLLED FLUORIDE EMISSIONS                  5-12
         5.3.1  Emissions from Wet-Process Phosphoric           5-12
                Acid Plants
         5.3.2  Emissions from Superphosphoric Acid             5-13
                Manufacture
         5.3.3  Emissions from Diammonium Phosphate             5-13
                Manufacture
         5.3.4  Emissions from Triple Superphosphate            5-13
                Manufacture and Storage
    5.4  GYPSUM POND EMISSIONS                                  5-15
    5.5  REFERENCES                                             5-18
6.  CONTROL TECHNIQUES FOR FLUORIDES FROM PHOSPHATE             6-1
    FERTILIZER PROCESSES
    6.1  SPRAY-CROSSFLOW PACKED BED SCRUBBER                    6-1
         6.1.1  Description                                     6-1
         6.1.2  Emission Reduction                              6-5
         6.1.3  Retrofit Costs for Spray-Crossflow              6-7
                Packed Bed Scrubbers
    6.2  VENTURI SCRUBBER                                       6-71
         6.2.1  Description                                     6-71
         6.2.2  Emission Reduction                              6-74
         6.2.3  Retrofit Costs for Venturi Scrubbers            6-75
    6.3  SPRAY TOWER SCRUBBER                                   6-78
         6.3.1  Description                                     6-78
         6.3.2  Emission Reduction                              6-78
                            m

-------
                                                                Page
         6.3.3  Retrofit Costs for Cyclonic Spray Towers        6-79
    6.4  IMPINGEMENT SCRUBBER                                   6-86
    6.5  SUMMARY OF CONTROL OPTIONS                             6-87
    6.6  DESIGN, INSTALLATION, AND STARTUP TIMES                6-88
    6.7  REFERENCES                                             6-95
7.  ECONOMIC IMPACT                                             7-1
    7.1  INTRODUCTION                                           7-1
    7.2  IMPACT ON MODEL PLANTS                                 7-2
    7.3  CRITERIA FOR PLANT CLOSURES                            7-4
    7.4  IMPACT ON THE INDUSTRY                                 7-6
    7.5  IMPACT ON EMPLOYMENT AND COMMUNITIES                   7-10
    7.6  SUMMARY                                                7-10
    7.7  REFERENCES FOR                                         7-12
8.  B1ISSION GUIDELINES FOR EXISTING                            8-1
    PHOSPHATE FERTILIZER PLANTS
    8.1  GENERAL RATIONALE                                      8-1
    8.2  EVALUATION OF INDIVIDUAL EMISSION GUIDELINES           8-4
         8.2.1  Wet-Process Phosphoric Acid Plants              8-4
         8.2.2  Superphosphoric Acid Plants                     8-6
         8.2.3  Diammonium Phosphate Plants                     8-7
         8.2.4  Run-of-Pile Triple Superphosphate Production    8-8
                and Storage Facilities
         8.2.5  Granular Triple Superphosphate Production       8-9
                Facilities
         8.2.6  Granular Triple Superphosphate Storage          8-11
                Facilities
   8.3  REFERENCES                                              8-13

                            iv

-------
9.  ENVIRONMENTAL ASSESSMENT                           9-1
    9.1  ENVIRONMENTAL ASSESSMENT OF THE EMISSION      9-1
         GUIDELINES
         9.1.1   Air                                    9-1
         9.1.2   Water Pollution                        9-9
         9.1.3   Solid Waste  Disposal                    9-12
         9.1.4   Energy                                 9-13
         9.1.5   Other Environmental  Concerns            9-18
    9.2  ENVIRONMENTAL ASSESSMENT OF ALTERNATIVE        9-18
         EMISSION CONTROL  SYSTEMS
    9.3  SOCIO-ECONOMIC EFFECTS                        9-19
    9.4'  REFERENCES                                    9-20

-------
                        LIST OF FIGURES

Figure                                                        Page
3-1      Wet-Process and Superphosphoric Acid Plant Locations  3-16
3-2      Triple Superphosphate and Ammonium Phosphate Plant   3-17
         Locati ons
3-3      Capacity Utilization of Wet-Process Phosphoric Acid  3-21
3-4      Capacity Utilization of Ammonium Phosphates          3-22
3-5      Wholesale Prices for Triple Superphosphate and       3-31
         Diammonium Phosphate
4-1     Major  Phosphate  Rock Processing Steps                 4-2
4-2     Flow Diagram  Illustrating a Wet-Process Phosphoric    4-5
        Acid Plant
4-3     Flow Diagram  for Prayon Reactor                       4-6
4-4     Operating Cycle  of Rotary Horizontal Tilting          4.9
        Pan Filter
4-5     TVA Evaporator for Producing Superphosphoric Acid     4-13
4-6     Submerged Combustion Process for Producing Super-     4-14
        phosphoric Acid
4-7     Stauffer Evaporator Process                           4-16
4-8     Swenson Evaporator Process                            4-16
4-9     TVA Diammonium Phosphate Process                      4-19
4-10    Run-of-Pile Triple Superphosphate Production and      4-22
        Storage
4-11    TVA Cone Mixer                                        4-23
4-12    TVA One-Step  Process for Granular Triple Super-       4-25
        phosphate
4-13    Dorr-Oliver Slurry Granulation Process for Triple     4-27
        Superphosphate
4-14    Granular Triple  Superphosphate Storage                4-28
                                vi

-------
Fj gure                                                              Page
6-1     Spray-Crossflow Packed Bed Scrubber                         6-2
6-2     Manufacture of Wet-Process Phosphoric Acid                  6-15
6-3     Existing Control  Equipment Layout for Model  WPPA Plant      6-17
6-4     Retrofit Control  Equipment Layout for Model  WPPA Plant      6-20
6-5     Retrofit Control  Equipment Layout for Model  SPA Plant       6-31
6-6     Existing Control  Equipment Layout for Model  DAP Plant       6-38
6-7     Retrofit Control  Equipment Layout for Model  DAP Plant       6-39
6-8     Existing Control  Equipment Layout for Model  ROP-TSP         6-47
        Plant, Case A
6-9     Retrofit Control  Equipment Layout for Model  ROP-TSP         6-51
        Plant, Case B
6-10    Existing Control  Equipment Layout for Model  GTSP            6-58
        Plant
6-11    Retrofit Control  Equipment Layout for Model  GTSP            6-59
        Plant
6-12    Gas Actuated Venturi Scrubber with Cyclonic Mist            6-73
        Eliminator
6-13    Water Actuated Venturi                                      6-73
6-14    Cyclonic Spray Tower Scrubber                               6-79
6-15    Retrofit Control  Equipment Layout for Model  ROP-TSP Plant   6-82
6-16    Doyle Scrubber                                              6-86
6-17    Time Schedule for the Installation of a Wet Scrubber on     6-89
        a Wet-Process Phosphoric Acid Plant
                             vii

-------
                            LIST OF TABLES
Table                                                         Page
1-1    Fluoride Emission Guidelines for                       1-8
       Existing Phosphate Fertilizer Manufacturing Plants
1-2    Performance of Aqueous Scrubber Emission Control       1-9
       Equipment in Phosphate Fertilizer Manufacturing Plants
1-3    Increments of Progress for Installation of Wet         1-10
       Scrubber for a Wet Process Phosphoric Acid Plant
1-4    Economic Impact of Fluoride Emission Guidelines for    1-12
       Existing Phosphate Fertilizer Manufacturing Facilities
1-5    Summary of Retrofit Control Cost Requirements for      1-13
       Various Phosphate Fertilizer Manufacturing Processes
2-1    Examples of HF Concentrations (PPB) and Exposure       2-8
       Durations Reported to Cause Leaf Damage and Poten-
       tial Reduction in Crop Values
3-1    Ten Largest Phosphate Rock Producers                   3-2
3-2    Ten Largest Phosphoric Acid Producers                  3-3
3-3    Production Capacity of Wet-Process Phosphoric          3-5
       Acid (1973)
3-4    Production Capacity of Superphosphoric Acid (1973)     3-8
3-5    Production Capacity of Triple Superphosphate (1973)    3-10
3-6    Production Capacity of Ammonium Phosphates (1973)      3-12
3-7    Production as Percent of Capacity                      3-19
3-8    U.S. Phosphate Consumption, 1960-1973 (1000 tons       3-24

3-9    U.S. Production of Three Commodities in the Phosphate   3-26
       Industry, 1950-1973
3-10   Summary of List Prices as of July 1974 and Basis       3-32
       for Quotation
3-11   United States and World Consumption of Phosphate       3-34
       Fertilizer
3-12   World  Reserves of  Phosphate  Rock  and  Apatite           3-35
                              vi i i

-------
Table                                                         Page
4-1    P205 Content of Phosphate Fertilizers                  4-3
4-2    Components of Typical  Wet-Process Acid                 4-10
4-3    Comparison of Orthophosphoric to Superphosphoric       4-11
       Acid
5-1    Fluoride Emissions from an Uncontrolled Wet-Process    5-4
       Phosphoric Acid Plant
5-2    Typical Material  Balance of Fluoride in Manufacture    5-6
       of Wet-Process Phosphoric Acid
5-3    Fluoride Emission Factors for Selected Gypsum Ponds    5-17
       at 90°F; Lbs/Acre Day
6-1    Calculated Equilibrium Concentrations of Fluorine in   6-5
       the Vapor Phase Over Aqueous Solutions of Fluosilicic
       Acid
6-2    Scrubber Performance in Wet-Process Phosphoric Acid    6-6
       Plants
6-3    Spray-Crossflow Packed Bed Scrubber Performance in     6-8
       Diammonium Phosphate and Granular Triple Super-
       phosphate Plants
6-4    Installed Cost Indices                                 6-10
6-5    Flow Rates and Fluoride Concentrations of WPPA Plant   6-18
       Effluent Streams  Sent  to Existing Controls (Case A)
6-6    Flow Rates and Fluoride Concentrations of WPPA Plant   6-19
       Effluent Streams  sent  to Retrofitted Controls (Case A)
6-7    Pond Water Specifications                              6-21
6-8    Major Retrofit Items for Model WPPA Plant (Case A)     6-22
6-9    Operating Conditions for Spray-Crossflow Packed        6-23
       Bed Scrubber for Model WPPA Plant, Case A (500
       Tons/Day P205)
6-10   Retrofit Costs for Model WPPA Plant, Case A (500       6-24
       Tons/Day P20g)
6-11   Flow Rates and Fluoride Concentrations of WPPA Plant   6-25
       Effluent Streams  Sent  to Existing Controls (Case B)
                             IX

-------
Table
Page
 6-12    Flow  Rates  and  Fluoride  Concentrations of WPPA         6-26
        Plant Effluent  Streams Sent  to  Retrofitted Controls
        (Case B)

 6-13    Major Retrofit  Items  for WPPA Plant  (Case B)           6-26

 6-14    Operating Conditions  for Spray-Crossflow Packed Bed    6-27
        Scrubber for Model WPPA  Plant,  Case  B
        (500  Tons/Day PgOg)

 6-15    Retrofit Costs  for Model WPPA Plant, Case B            6-28
        (500  Tons/Day P205)

 6-16    Major Retrofit  Items  for Model  SPA Plant               6-32

 6-17    Operating Conditions  for Spray-Crossflow Packed Bed    6-33
        Scrubber for Model SPA Plant (300 Tons/Day P205)

 6-18    Retrofit Costs  for Model SPA Plant (300 Tons/Day       6-34

        P2°5>

 6-19    Flow  Rates  and  Fluoride  Concentrations for DAP Plant   6-36
        Emission Sources

 6-20    Major  Retrofit  Items  for Model  DAP Plant               6-40

 6-21    Operating Conditions  for Spray-Crossflow Packed        6-41
        Bed Scrubbers for Model  DAP Plant (500 Tons/Day

        W

 6-22    Retrofit Costs for Model DAP Plant (500 Tons/Day       6-42

        P2°5>

 6-23    Flow Rates  and Fluoride Concentrations for ROP-TSP     6-44
        Plant Emission Sources

6-24   Major Retrofit Items for Model   ROP-TSP Plant           6-45
        (Case A)

6-25   Operating Conditions for Spray-Crossflow Packed Bed    6-46
       Scrubber for Model ROP-TSP Plant, Case A (550 Tons/
       Day P205)

6-26   Retrofit Costs for Model  ROP-TSP Plant, Case A (550    6-48
       Tons/Day P20g)

6-27   Flow Rates and Fluoride Concentrations of Effluent     6-49
       Streams Sent to Existing Controls

-------
Table                                                         Page
6-28   Major Retrofit Items for Model  ROP-TSP Plant (Case B)   6-52
6-29   Operating Conditions for Spray-Crossflow Packed Bed    6-53
       Scrubber for Model  ROP-TSP Plant, Case B (550 Tons/
       Day P205)
6-30   Retrofit Costs for Model ROP-TSP Plant, Case B         6-54
       (550 Tons/Day P205)
6-31   Flow Rates and Fluoride Concentrations for GTSP        6-57
       Plant Emission Sources
6-32   Major Retrofit Items for Model  CTSP Plant              6-61
6-33   Operating Conditions for Spray-Crossflow Packed        6-64
       Bed Scrubbers for Model GTSP Plant (400 Tons/Day
       P2°5>
6-34   Retrofit Costs for Model GTSP Plant (400 Tons/Day      6-65
       P2°5'
6-35   Operating Characteristics of Scrubbers in Retrofit     6-68
       Case A
6-36   Case B Retrofit Project Costs                          6-70
6-37   Venturi Scrubber Performance in Superphosphoric        6-74
       Acid and Diammonium Phosphate Plants
6-38   Major Retrofit Items for Model  DAP Plant               6-75
6-39   Retrofit Costs for Model DAP Plant (500 Tons/Day       6-77
       P2°5>
6-40   Cyclonic Spray Tower Performance in Wet-Process        6-80
       Phosphoric Acid, Diammonium Phosphate, and Run-of-
       Pile Triple Superphosphate Plants
6-41   Major Retrofit Items for Model  ROP-TSP Plant           6-83
6-42   Operating Conditions for Cyclonic Spray Tower          6-84
       Scrubbers for Model ROP-TSP Plant (550 Tons/Day
       P2°5>
6-43   Retrofit Cost for Model ROP-TSP Plant  (550 Tons/Day    6-85
       P205>
                             XI

-------
Table                                                         Page

6-44   Estimated Total Capital Investment and Annualized      6-87
       Cost for DAP and ROP-TSP Retrofit Models using
       Spray-Crossflow Packed Bed and Alternative Scrubbers

6-45   Description of Individual Activities Involved in the   6-90
       Procurement, Installation, and Startup of Control
       Equipment

7-1    Summary of Retrofit Control Cost Requirements for      7-2
       Various Phosphate Fertilizer Manufacturing Processes

9-1    Annual U.S. Fluoride Emission Reduction Due to Instal- 9-2
       lation of Retrofit Controls Capable of Meeting
       Emission Guidelines

9-2    Typical 1974 Fluoride Emissions Source Strengths Be-'   9-3
       fore and After Installation of Retrofit Controls
       Capable of Meeting Emission Guidelines
9-3    Existing Controls and Emissions for Model Phosphate    9-5
       Fertilizer Complex

9-4    Retrofit Controls and Emissions for Model Phosphate    9-6
       Fertilizer Complex

9-5    Estimated 30-Day Average Ambient Fluoride Concentra-   9-8
       tions Downwind of a Phosphate Fertilizer Complex

9-6    Comparison of Emission Guidelines and an Alternative   9-10
       Standard

9-7    EPA Effluent Limitations for Gypsum Pond Water         9-11

9-8    Incremental Power Requirements for Fluoride Control    9-14
       Due to Installation of Retrofit Controls to Meet
       Emission Guidelines

9-9    Increase in Phosphate Industry Energy Requirements     9-16
       Resulting from Installation of Retrofit Controls
       to meet Emission Guidelines

9-10   Increased Electrical Energy Demand by the Phosphate    9-17
       Industry as a Result of Installation of Retrofit
       Controls
                            xn

-------
                1.  INTRODUCTION AND SUMMARY
1.1  INTRODUCTION
     Section lll(d) of the Clean Air Act, 42 U.S.C. 1857c-6(d), as
amended, requires EPA to establish procedures under which States submit
plans to control certain existing sources of certain pollutants.  On
November 17, 1975 (40 FR 53340), EPA implemented section lll(d) by
promulgating Subpart B of 40 CFR Part 60, establishing procedures and
requirements for adoption and submittal  of State plans for control of
"designated pollutants" from "designated facilities."  Designated
pollutants are pollutants which are not included on a list published
under section 108(a) of the Act (national Ambient Air Quality Standards)
or section 112(b)(l)(A) (Hazardous Air Pollutants), but for which
standards of performance for new sources have been established under
section lll(b).   A designated facility is an existing facility which
emits a designated pollutant and which would be subject to a standard
of performance for that pollutant if the existing facility were new.
     Standards of performance for five categories of new sources in
the phosphate fertilizer industry were promulgated in the FEDERAL
REGISTER (40 FR 33152) on August 6, 1975, to be incorporated into the
Code of Federal  Regulations under 40 CFR Part 60.  New subparts T, U,
V, W, and X were added to set standards of performance for fluoride
emissions from new plants manufacturing wet-process phosphoric acid
(WPPA), superphosphoric acid (SPA), diammonium phosphate (DAP),
triple superphosphate (TSP), and for storage facilities used in the
manufacture of granular triple superphosphate (GTSP).  The States,
therefore, are required to adopt fluoride emission standards for

                              1-1

-------
existing  phosphate fertilizer plants  which  would  be  subject to the
standard  of performance if they were  new.
      Subpart B of 40 CFR Part 60 provides that  EPA will publish a
guideline document for development of State emission standards after
promulgation of any standard of performance for a designated
pollutant.   The document will  specify emission  guidelines and times
for compliance and will  include other pertinent information, such as
discussion  of the pollutant's  effects on public health and welfare
and a description of control  techniques and their effectiveness and
costs.  The  emission guidelines will  reflect the  degree of emission
reduction attainable with the  best adequately demonstrated systems of
emission  reduction,  considering costs as applied  to existing facilities.
     After  publication of a  final  guideline document for the pollutant
in question,  the  States  will  have  nine months to  develop and submit
plans for control  of that pollutant from designated facilities.   Within
four months  after the date for submission of plans, the Administrator
will approve  or disapprove each plan  (or portions thereof).  If a
state plan  (or  portion thereof) is  disapproved, the Administrator will
promulgate a  plan  (or portion  thereof) within six months after the
date for plan submission.  These and  related provisions of subpart B
are basically patterned  after  section  110 of the  Act and 40 CFR  Part
51 (concerning  adoption  and  submittal  of state  implementation plans
under section 110).
     As discussed  in  the  preamble  to  subpart B, a distinction is drawn
between designated pollutants  which may cause or  contribute to
endangerment of public health  (referred to  as "health-related pollutants")
                               1-2

-------
and those for which adverse effects on public health have not been
demonstrated (referred to as "welfare-related pollutants").  For
health-related pollutants, emission standards and compliance times in
state plans must ordinarily be at least as stringent as the corresponding
emission guidelines and compliance times in EPA's guideline documents
As provided in Subpart B, States may apply less strinaent requirements
for particular facilities or classes of facilities when economic
factors or physical limitations make such application sicinificantly
more reasonable.
     For welfare-related pollutants, States may balance the emission
guidelines, times for compliance, and other information provided in
a guideline document against other factors of public concern in
establishing emission standards, compliance schedules, and variances,
provided that appropriate consideration is given to the information
presented in the guideline document and at public hearing(s) required
by subpart B and that all other requirements of subpart B are met.
Where sources of pollutants that cause only adverse effects to crops
are located in non-agricultural areas, for example, or where residents
of a community depend on an economically marginal plant for their
livelihood, such factors may be taken into account (in addition to
those that would justify variances if a health-related pollutant
were involved).   Thus, States will have substantial flexibility to
consider factors other than technology and cost in establishing plans
for the control  of welfare-related pollutants  if they wish.
     For reasons discussed  in  section 2 of this document,  the
Administrator has determined that fluoride emissions from  phosphate
                              1-3

-------
 fertilizer plants  may cause or contribute to  endangerment of the
 public welfare but that adverse effects  on public  health have not
 been  demonstrated.  As discussed above,  this  means that fluoride
 emissions  will  be  considered a welfare-related  pollutant and the
 States will  have greater flexibility in  establishing  plans for the
 control  of fluorides than would be the case if  public health might
 be affected.
      This  guideline document provides a  brief description of the
 phosphate  fertilizer industry, the five  manufacturing categories
 for which  fluoride emission guidelines are established, and the
 nature and source  of fluoride emissions.   Also,  information is provided
 regarding  the  effects of airborne fluorides on  health, crops, and
 animals.
      Emphasis  has  been placed on the technical  and economic evaluation
 of control  techniques that are effective in reducing  particulate and
 gaseous  fluoride emissions, with particular emphasis  on retrofitting
 existing plants.   Some costs were frequently  not available and were
 fragmentary.   Therefore, the cost basis  for adoption  of State
 standards  based on the emission guidelines is instead developed by
 engineering cost estimates on a hypothetical  phosphate fertilizer
 plant complex  where assumed marginally acceptable  controls are replaced
with controls based  on the emission  guidelines.  These retrofits are
called retrofit models and  are  presented  in Section 6.1.3.1.
     The emission  guidelines  and  the  control  equipment on which
they are based are discussed  in Sections  7  and 8.  The environmental
                              1-4

-------
assessment of the emission guidelines is presented and discussed in
Section 9.  The remainder of this introductory section summarizes
information presented in subsequent sections.
 1.2  HEALTH AND  WELFARE  EFFECTS  OF  FLUORIDES
      Fluoride emissions  from  phosphate  fertilizer  plants  have  been
 determined to be welfare-related [i.e.  no demonstrated  impact  upon
 public  health for purpose of  section  lll(d)].  The daily  intake  of
 fluoride  inhaled from the ambient air is only a few hundredths of a
milligram - a very small fraction of the total intake of  the average
person.   If a person is  exposed  to  ambient air containing about
eight micrograms (yg) of fluoride per cubic  meter, which  is the
maximum average concentration that  is projected in the vicinity  of a
fertilizer facility with only moderate control equipment  (Table  9-5),
his total daily intake from this source is calculated to be about 150
yg.  This is very low when compared with the estimated daily intake
of about  1200 yg from food, water and other  sources for the average
person.   Also,  the intake of fluoride indirectly through standard
food chains  is  insignificant.   Fluorides are not passed  into dairy
products and  are  only found in farm produce  in very small  amounts.
     Fluorides do, however, cause damage to  livestock and vegetation
in the immediate vicinity of fertilizer plants.  Ingestion .of
fluorides by livestock from hay and forage causes bone lesions,
lameness and impairment of appetite that can result in decreased
weight gain  or  diminished milk yield.  It can also affect developing
teeth in young  animals,  causing more or less severe abnormalities
                              1-5

-------
in permanent teeth.  Exposure of plants to atmospheric fluorides can
result in accumulation, foliar lesions, and alteration in plant
development, growth, and yield.
1.3   FLUORIDES AND THEIR  CONTROL
      For  purposes  of standards of  performance  for new stationary
sources  (SPNSS)  and the attendant  requirements of section lll(d),
emissions of  "total  fluorides," rather  than specific fluorides are
limited.  Total  fluorides  means elemental  fluorine and all compounds
of fluorine measured by reference  methods  identified in subparts T,
U, V, W,  and  X and specified  in Appendix A of  40 CFR, Part 60, or
equivalent or alternative  test methods.
      Good control  of fluoride emissions from phosphate fertilizer
manufacturing operations  is achievable  by  water scrubbers which are
properly designed,  operated, and maintained.   The most satisfactory
scrubber for general  use seems to  be  the spray crossflow packed
scrubber.  Other scrubbers, such as the venturi and the cyclonic
spray tower can  give satisfactory  results when used in series.  The
spray-crossflow  packed scrubber, shown diagramatically in Figure 6-1,
owes much of its success to its greater fluoride absorption capability
and its relative freedom from solids  plugging.  This plugging has qiven
some trouble in  the  past in DAP and GTSP plants, but current designs
are available which  have acceptable turnaround periods .   One design
involves a venturi  ahead of, and integral  with, the scrubber.
     A description of the  performance of water scrubbers in fluoride
emission control is  given  in Table 1-1.  The industry-wide range of
control is given by  a variety of scrubbers and is discussed in Chapter
                              1-6

-------
6.  The scrubber data associated with best control technology was
obtained from EPA sponsored tests conducted during the development
of SPNSS.  Most of the scrubbers tested were the spray crossflow
packed type, but a few venturi were tested.
1.4   EMISSION GUIDELINES
      Emission guidelines for existing phosphate fertilizer manufacturing
facilities for control of fluoride emissions are described in this
Section.  Table 1-1 gives the fluoride emission levels that may  be
achieved by application of best adequately demonstrated technology to
existing facilities, including five manufacturing processes and the
storage facilities for granular triple superphosphate.  Comparison of
these emission guidelines with the ranges shown for well-controlled
plants (Table 1-1) shows that equivalent control  of fluoride emissions
can be achieved by application of best adequately  demonstrated  technology
for either new or existing sources.
      Adoption of these controls would result in fluoride emission
reductions ranging from about 50 percent for granular triple super-
phosphate (6TSP) production facilities to around 90 percent for
run-of-pile triple superphosphate (ROP-TSP) plants.  Overall nationwide
emissions would be reduced by about 75 percent.
     The emission levels of Table 1-2 are identical to the standards
of performance for new stationary sources (SPNSS)  since the best
adequately demonstrated technology applicable is  the same type of
control  equipment.   The justification for application of  this equipment
to existing  as well  as new sources  is summarized  in Section 1.6.1
and discussed more completely in Section  8.
                              1-7

-------
                   TABLE 1-1   PERFORMANCE OF AQUEOUS SCRUBBER  EMISSION CONTROL  EQUIPMENT
                                  IN PHOSPHATE FERTILIZER MANUFACTURING PLANTS.
         Fluoride Source
00
Wet-Process Phosphoric Acid
Superphosphoric Acid
     Submerged Combustion
     Vacuum Evaporation
Diammonium Phosphate
Triple Superphosphate
(run-of-pile - ROP)
Granular Triple Superphosphate
Granular Triple Superphosphate
Storage
                                                Fluoride Emissions from Control Equipment
                                                    g TF/kg   of PO  input
Industry-Wide Ranne
    0.01  -  0.030

       0.06
    2.5 x 1.0"3
    0.03  -  0.25
    0.10  -  1.30

    0.10  -  1.30
                                                 2.5 x 10"4 - 7.5 x 10"4*
                                                                            Best-Controlled Senment
                                                                                 0.001 - 0.0095
2.05 x 10"4 - 7.5 x 10~4
0.0125 - 0.03
0.015 - 0.1505

0.02 - 0.135
                                    0.25 x 10"4 - 2.75 x 1C"4
         "Units are g TF/hr/kg  of  P205  stored,

-------
          TABLE  1-2   FLUORIDE EMISSION GUIDELINES  FOR  EXISTING
                          PHOSPHATE FERTILIZER MANUFACTURING PLANTS.
Process Source
 of Fluorides
Wet-Process Phos-
phoric Add

Supcrphosphoric Add

Diammonium Phosphate

Triple Superphosphate
       (ROP)

Granular Triple
Superphosphate
Granular Triple
Superphosphate Storage
               Emission  Guidelines
Total Fluorides
^
0.01
0.005
0.030
0.100

0.100
g/hr kilogram
- weiqht ppr unit nf P*>fic
Ibs/ton
0.02
0.01
0.06

0.2
0.2
input







Ibs/hr ton*
2.5 x 10
        -4
5 x 10'4
*These denominator units are 1n terms  of P205  stored,

-------
  1.5  COMPLIANCE TIMES
       The  compliance times for installation  of a  wet  scrubber are given
  in  Table  1-3,  which is  derived from Figure  6-15.  Milestones in the
  compliance  schedule are also shown.   The  first milestone can increase
  to  18 weeks  if justifiable  source  tests must  be  run  and control
  alternatives evaluated.   This is rather unlikely, since the spray-
  crossflow packed scrubber is the one  most widely specified for new
  controls.  The interval  between milestones  two and three is that required
  for fabrication and  shipping.  The fabrication time  is virtually beyond
  the control of either the customer or the air  pollution control
 official.  For this  reason,  a  range of elapsed time must be understood
 for fabrication.  The compliance time can exceed 100 weeks and  depends
 upon availability of materials of construction, labor factors,  work
                           TABLE 1-3
     COMPLIANCE TIMES FOR  INSTALLATION OF WET SCRUBBER FOR
     	A WET PROCESS PHOSPHORIC ACID PLANT	
              Milestone                Elapsed Time.  Weeks
     Submit final control plan                  6
       to Agency
     Award scrubber contract                   26
     Initiate scrubber                         52
       installation
     Complete scrubber                         72
       installation
     Final  compliance achieved                 74
backlogs, and many other things.  If a given fertilizer complex  has
to install several scrubbers,  the total time for compliance may  exceed
                              1-10

-------
that for only one scrubber.   In practice, enforcement officials should
try to consider each plant on a case-by-case basis  and should require
proof for the time requirements claimed for each milestone.
1.6  ASSESSMENTS
1.6.1  Economic
     The information shown in Table 1-4 provides a major portion of
the justification for the emission guidelines.  The costs in the
table were derived from retrofit models  (section 6.1.3.1).  The capital
and annualized costs shown in Table 1-4 represent emission controls
for each separate process.
     Actual total expenditures for emission controls of a process
have to take into account the control costs allocated to its feed
materials.  Table 1-5 summarizes retrofit control costs for fertilizer
plants of the capacities shown.  These costs  (see Table 7-1) include
prorated WPPA plant control costs according to the amount of acid
used.  For example, the ROP plant control cost includes the control
cost for the 330 tons/day of wet process phosphoric acid required to
make 550 TPD of ROP, both on a PgOg basis.  Therefore, the annualized
control costs, as a percent of sales, differ  from those shown  in
Table 1-4, except for the WPPA plant taken alone.  The greatest unit
basis cost is for the combination of processing and storage of GTSP.
About 75,percent of GTSP production is believed to be already
sufficiently controlled while five of eight storate facilities may
need to be retrofitted if the States establish emission standards as
stringent as the emission guidelines.  This would not have a great
effect on GTSP manufacture.  About 60 percent of DAP plants would
                            1-11

-------
                        TABLF 1  4     ECONOMIC ASSESSMENT Of FLUORIDE EMISSION GUIDELINES  FOR  EXISTING
                                              PHOSPHATE FERTILIZER MANUFACTURING FACILITIES.*
Process Source of
Fluorides


Wet- Process
Phosphoric Acid
jSuperphosphoric
jAcid
|Di ammonium
; Phosphate
Triple Super-
Phosphate (ROP)
Granular Triple
[Superphosphate
^Granular Triple
Superphosphate
Storage
Annual i zed
Control Cost
% of Sales

0.19 - 0.23
0.3
0.37
0.40 - 0.70
0.44
0.40
Capital Control
'• Cost of Equipment
$/short ton of
P2°5
1.26 - 1.51
1.04
4.00
4.00 - 6.85
4.55
4.10
Pprcent of Plants
* Not Meeting This
Emission Guidelines
i
47
21
60
40
25
70
Applicable
Emission
Guideline
grams/kilogram P2o5 input
0.01
0.005
0.03
0.1
0.1
2.5 x 10 *
ro
        *  Derived from EPA retrofit models.

       **  Based upon total annual production at capacity for 330 days/year.

       **  Units are grams F/hr/kilogram of PJ)- stored.  This facility is
           assumed to accompany a 400 short ton°P205/day GTSP plant.

-------
                                     TABLE  1-5
SUMMARY OF RETROFIT CONTROL COST REQUIREMENTS FOR VARIOUS PHOSPHATE FERTILIZER MANUFACTURING PROCESSES
End Product
Design Rate, short
tons/day
(Pj>0s Basis)
Capital Control Cost,
$/short ton P205
Sales Price
($ per ton product)
Annual i zed Costs
Unit Basis
($ per ton product)
As a % of
Sales Price
Phosphoric
Acid
500
1.26 - 1.51
105

0.19 - 0.23
0.2
Superphosphoric
Acid
i
300
2.42
152

0.48
0.3
DAP
500
5.35
145

0.68
0.5
ROP-TSP ' GTSP
1
i
i
550
4.80 - 8.05
126

0.66 - 1.03
0.5 - 1.0
400
9.35
130

1.18
0.9
 Based upon 90 percent capacity factor.

-------
possibly need to be retrofitted.  Although this segment of the industry
requires the most control effort, control costs are only 0.5 percent of
sales.
     The capital retrofit costs shown in Table 1-5, while significant,
are moderate.  Annualized costs as a percent of sales are small,
showing that all the control costs can be readily recovered.
     Cyclonic spray and venturi scrubbers, alone, do not have more
than about two transfer units, whereas the spray-crossflow packed
scrubber (SCPS) is furnished in the 5-9 transfer unit.range.  The
former controls would require two or more scrubbers in series to
achieve the performance of one spray-crossflow packed scrubber.  This
scrubber multiplication would cost more in comparison to the SCPS
and would not be selected for high degrees of fluoride removal when
costs are taken into account.  Having made this choice, there is no
reason to design short of the SPNSS.  A SCPS designed to achieve 0.08
Ibs F/ton for DAP can achieve 0.06 Ibs TF/ton with a little additional
packing.  Therefore, the fluoride emission guidelines given in Table
1-1 reflect the performance of a control system which is judged to be
the best when costs are taken into account, and they are identical to
the SPNSS.
     If the States establish emission standards as stringent as the
emission guidelines, the financial impact upon most existing plants
will be moderate, as shown in Tables 1-4 and 1-5.  The only plants
likely to be financially burdened will be:  small plants of less than
about 170,000 tons per year capacity; plants that are 20 years or more
of age; and plants isolated from raw materials, i.e. certain DAP plants
that purchase merchant phosphoric acid and ammonia.
                             1-14

-------
 1.6.2  Environmental
      The environmental assessment provided here is an assessment of
 the difference between two degrees of control:  1) the reduction on
 fluoride emissions resulting from application of the emission
 guidelines and 2)  the normal  reduction in  fluoride emissions resulting
 from State Implementation  Plans  (SIP), local  regulations,  etc.
      The adoption  of fluoride emission standards would have a
 beneficial impact  upon air quality.   Installation of retrofit controls
 similar to those described in section 6.1.3.1 can reduce fluoride
 emissions from existing sources  by amounts ranging from 50 percent
 for GTSP storage to 90 percent for ROP-TSP plants.  The projected
 average nationwide emission  reduction that would result from applica-
 tion of the emission guidelines  is 74.5 percent or 1250 tons F/year.
 The method of  deriving these  results  is described in section 9.1.1.
      The removal of fluoride  pollutants from  fertilizer plant emissions
 would have a beneficial  effect on  the environment.   The threshold
 average  concentration  of fluoride  in  foliage  that results  in harmful
 effects  to animals when  ingested is 40 ppm.   The  available  data
 suggest  that a threshold for  plant deterioration  (foliar necrosis)
 on  sensitive plant species is  also 40  ppm.  As  discussed in  detail
 in  Chapter 2, an accumulation  of fluoride  in  foliage of more  than 40
 ppm would  result from exposure to a 30  day average air concentration
 of  gaseous fluoride of about 0.5 micrograms per cubic meter  (yg/m3).
 In  order to evaluate potential ambient concentrations of fluoride,
atmospheric dispersion estimates  were made for a typical phosphate
fertilizer complex.  Groundlevel  fluoride concentrations were compared
for marginally acceptable controls and for controls essentially
                               1-15

-------
similar to the emission guidelines shown in Table 1-1.   At a distance
of about 2.5 kilometers  (Table 9-5) from the complex, the 30-day
average fluoride ground-level concentration was 3.5 ug/m  for the
marginally acceptable controls, and it was 0.5 ug/m  for the good
retrofit controls.  The conclusion is apparent that for protection
of public welfare  (i.e. foliage, animals, etc.) marginally acceptable
controls are effective for  protection of property beyond 15 km (9.3
miles) and best controls are effective beyond 2.5 km (1.5 miles)
relative to the fertilizer  facility location.
     Increased or  decreased control of fluorides would not change
the volume of aqueous waste generated in a phosphate fertilizer
complex.  Gypsum pond water is used and re-used, and a discharge is
needed only when there is rainfall in excess of evaporation.
     Any solid waste generated by scrubbing fluorides would be in
the form of fluorosilicates of CaF2 in the gypsum ponds.  Section
9.1.3 shows that the increase in solids discharged to the gypsum
pond due to scrubbing in a  WPPA plant is only about 0.06 weight
percent, a negligible amount.  The total fluoride solids increase
from a fertilizer  complex to the gypsum pond would be nearer four
percent of the gypsum discharge, but much of this is from sources
other than scrubbing and certainly cannot be charged to small
increments in emission standards.
1.6.3  Energy
     Energy requirements for State controls based on the
emission guidelines, in excess of existing controls, would be small
and varying from 0.4 to 25  KWH per ton PoOci depending on the
process.  Raising  the allowable emission levels would have only a
                               1-16

-------
small effect on these power figures.  Section 9.1.4 estimates the
total incremental energy demand for the phosphate fertilizer industry.
This total incremental electrical energy demand that would result from
installation of retrofit controls to meet State controls based on the
guidelines is estimated as 27 x 106 KWH/yr, which is energy enough to
operate one SPA plant of 300 tons/day P205 for 115 days/year.  Although
this energy number can be only an approximation, it puts the
incremental energy demand into perspective and shows that it is very
small compared to the total annual energy demand for the industry.
1.7  REFERENCES
1.  Private communications, George B.  Crane and Teller Environmental
    Systems, Inc., December 13, 1974.
2.  Biologic Effects of Atmospheric Pollutants; Fluorides.  National
    Academy of Sciences.  Washington,  D. C.  Contract No. CPA 70-42.
    1971.
3.  Beck, Leslie L., Technical  Report:  An Investigation of the Best
    Systems of Emission Reduction for the Phosphate Fertilizer
    Industry.  U. S. Environmental Protection Agency, Office of Air
    Quality Planning and Standards, Research Triangle Park, North
    Carolina.  April 1974.
                               1-17

-------
          2.  HEALTH AND WELFARE EFFECTS OF FLUORIDES
 2.1   INTRODUCTION
      In accordance with 40 CFR 60.22(b), promulgated on November 17,
 1975  (40 FR 53340), this chapter presents a summary of the available
 information on the potential health and welfare effects of fluorides
 and the rationale for the Administrator's determination that is is a
 welfare-related pollutant for purposes of section lll(d) of the Clean
 Air Act.
      The Administrator first considers potential health and welfare
 effects of a designated pollutant in connection with the establishment
 of standards of performance for new sources of that pollutant under
 section lll(b) of the Act.  Before such standards may be established,
 the Administrator must find that the pollutant in question "may
 contribute significantly to air pollution which causes or contributes
 to the endangerment of public health or welfare" [see section
 lll(b)(l)(a)].  Because this finding is, in effect, a prerequisite
 to the same pollutant's being identified as a designated pollutant
 under section lll(d),  all  designated pollutants will have been
 found to have potential adverse effects on public health, public
welfare, or both.
     As discussed in section 1.1  above, Subpart B of Part 60
 distinguishes between  designated  pollutants that may cause or
 contribute to endangerment of public health (referred to as "health-
 related pollutants") and those for which adverse effects on public
 health have not been demonstrated ("welfare-related pollutants").
 In general, the significance of the distinction is that States
have more flexibility  in establishing plans for the control of
                             2-1

-------
 welfare-related pollutants than is provided for plans .involving
 health-related pollutants.
      In determining whether a designated pollutant is health-related
 or welfare-related for purposes of section lll(d), the  Administrator
 considers such factors as:  (1) Known and suspected effects  of the
 pollutant on public health and welfare;  (2) potential ambient
 concentrations of the pollutant; (3)  generation of any  secondary
 pollutants for which the designated pollutant may be a  precursor;
 (4)  any synergistic effect with other pollutants; and (5) potential
 effects from accumulation in the environment (e.g.,  soil, water and
 food chains).
     It should be noted that the Administrator's  determination
 whether a designated pollutant is health-related  or  welfare-related
 for purposes  of section lll(d) does not  affect the degree of control
 represented  by EPA's emission  guidelines.   For reasons  discussed in
 the preamble  to Subpart B, EPA's emission  guidelines [Vike standards
 of performance for  new sources under  section  lll(b)] are based on the
 degree  of control achievable with the best adequately demonstrated
 control  systems (considering costs),  rather than  on  direct protection
 of public health  or welfare.   This  is  true whether a particular
 designated pollutant has  been  found to be  health-related or welfare-
 related.  Thus, the only  consequence  of  that  finding is the deqree
of flexibility  that will  be  available  to the  States  in establishing
plans for control of the  pollutant, as indicated above.
                              2-2

-------
 2.2   EFFECT OF FLUORIDES ON HUMAN HEALTH.
                                         1
2.2.1  Atmospheric Fluorides
     The daily intake of fluoride inhaled from the ambient air is
only a few hundredths of a milligram --a very small fraction of the
total intake for the average person.  If a person is exposed to
ambient air containing about 8 micrograms (yg) of fluoride per cubic
meter, which is the maximum average concentration that is projected
in the vicinity of a fertilizer facility with only mediocre control
equipment (Table 9-5), his total daily intake from this source is
calculated to be about 150 yg.  This is very low compared with the
estimated daily intake of about 1200 yg from food, water, and other
sources for the average person.
     Few instances of health effects in people have been attributed
to community airborne fluoride, and they occurred  in investigations
of the health of persons living in the immediate vicinity of fluoride-
emitting industries.  The only effects consistently observed are
decreased tooth decay and slight mottling of  tooth enamel when compared
to control  community observations.  Crippling fluorosis  resulting  from
industrial  exposure  to  fluoride seldom  (if  ever)  occurs  today, owinq
to the establishment of and adherence to  threshold  limits for  exposure
of workers  to fluoride.   It has never been  seen  in  the United  States.
Even persons occupationally exposed to airborne  fluoride do not  usually
come in contact with fluoride concentrations  exceeding the recommended
industrial  threshold limit values  (TLV).  The  current TLV for  hydrogen
fluoride is 3 parts  per million (ppm) while that for particulate
fluoride is 2.5 milligrams per cubic meter  (mg/m3) expressed as elemental
fluorine.
                              2-3

-------
      There is evidence that airborne fluoride concentrations that
 produce no plant injury contribute quantities of fluoride that are
 negligible in terms of possible adverse effects on human health and
 offer a satisfactory margin of protection for people.
      Gaseous hydrogen  fluoride  is absorbed from the respiratory tract
 and  through the skin.  Fluoride  retained  in  the body is found almost
 entirely  in the bones  and  teeth.  Under normal conditions, atmosnheric
 fluoride  represents only a very  small  portion of the body fluoride
 burden.
 2.2.2  Ingested  Fluorides
      Many  careful  studies,  which were  reviewed  by  the National Academy
 of  Sciences,  have  been  made of human populations living  in the  vicinity
 of  large stationary sources of fluoride emissions.   Even  in  situations
 where poisoning  of grazing  animals was present, no  human  illness due
 to  fluoride poisoning has been found.   In  some  of  these  areas much of
 the food used by the people was  locally produced.   Selection, processing
 and cooking of vegetables,  grains and  fruits  gives  a much lower fluoride
 intake  in  human diets than  in  that of  animals grazina on contaminated
 pasture.
      In poisoned animals, fluorine levels  are several thousand times
 normal  in  bone, and barely  twice  normal in milk or meat.  Calves and
 lambs nursing from  poisoned mothers do not have fluorosis.  They do not
 develop poisoning until they begin to  graze.  Meat, milk and eqqs from
 local animals contain very  little more fluoride than the same foods
 from  unpoisoned animals.  This is due  to the  fact that fluorine is
deposited  in the bones  almost  entirely.
                              2-4

-------
 2.3  EFFECT  OF  FLUORIDES ON ANIMALS.1
      In areas where fluoride  air  pollution  is  a  problem, high-
 fluoride vegetation is  the  major  source  of  fluoride  intake by livestock,
 Inhalation contributes  only a negligible amount  to the total fluoride
 intake of such  animals.
      The available  evidence indicates  that  dairy cattle are the
 domestic animals most sensitive to fluorides,  and protection of
 dairy cattle from adverse effects will protect other classes of live-
 stock.
      Ingestion  of fluoride  from hay and  forage causes bone lesions,
 lameness,  and impairment of appetite  that can  result  in decreased
 weight  gain  or  diminished milk yield.  It can  also affect  developing
 teeth  in young  animals, causing more or  less severe abnormalities
 in  permanent teeth.
      Experiments have indicated that long-term ingestion of 40 ppm
 or more  of fluoride in the ration of dairy cattle will  produce a
 significant  incidence of lameness, bone lesions, and dental
 fluorosis, along with an effect on growth and milk production.
 Continual  ingestion of a ration containing less  than 40 ppm will give
discernible but  nondamaginq  effects.  However,  full  protection
 requires that a time limit be placed on the period during which high
 intakes  can  be  tolerated.
      It  has  been suggested that dairy cattle can tolerate the
 ingestion  of forage that averages 40 ppm of fluoride for a year,
 60  ppm for up to 2 months and 80  ppm for up to 1 month.  The usual
 food  supplements are low in fluoride and will  reduce the fluoride
 concentration of the total  ration to the extent  that they are fed.
                              2-5

-------
      Fluoride-containing dusts can be non-injurious to vegetation
 but contain hazardous amounts of fluoride in terms of forage for
 farm animals.  Phosphate rock is an example of a dust that seemingly
 has not injured plants but is injurious to farm animals.  This was
 made evident forty years ago when an attempt was made to feed
 phosphate rock as a dietary supplement source of calcium and phosphate.
 Fluoride injury quickly became apparent.2  Phosphate rock is used
 for this purpose today, but only after defluorinating by heat treat-
 ment.   Phosphate rock typically contains up to about 4 weight percent
 fluorine.

 2.4  EFFECT OF ATMOSPHERIC FLUORIDES ON VEGETATION.1
     The  previous sections state that atmospheric fluorides are
not a direct problem to people or animals in  the United States, but
 that  animals could be seriously harmed by ingestion of fluoride  from
 forage.   Indeed, the more important aspect of fluoride in the ambient
 air is its effect on  vegetation and its accumulation  in  foraqe
 that leads to  harmful effects  in cattle ana otner  animals,   fne
 hazard to these receptors  is limited  to particular areas:   industrial
 sources  having  poorly controlled fluoride emissions and  farms located
 in close proximity to facilities emitting  fluorides.
      Exposure of plants to atmospheric fluorides can  result  in
 accumulation, foliar lesions, and alteration in  plant  development,
 growth, and yield.   According to their response  to  fluorides, plants
 may be classed as sensitive,  intermediate, and resistant.  Sensitive
plants include  several conifers, several fruits and berries, and some
grasses such as  sweet  corn and sorghum.  Resistant  plants include
                              2-6

-------
several  deciduous  trees and numerous veaetable and field crops.  Most
forage crops are tolerant or only moderately susceptible.   In
addition to differences among species and varieties, the duration of
exposure, stage of development  and  rate  of  growth,  and  the environmer.tpl
conditions and agricultural  practices  are important factors  in
determining the susceptibility of plants to fluorides.
     The average concentration of fluoride  in or on foliage  that appears
to be important for animals is 40 ppm.  The available data  suggest
that a threshold for significant foliar necrosis on sensitive
species, or an dccumulation of fluoride in forage  of more than  40 ppm
would result from exposure to a 30-day average  air concentration of
gaseous fluoride of about 0.5 micrograms per cubic  meter (yg/m3).
     Examples of plant fluoride exposures that relate to leaf
damage and crop reduction are shown in Table 2-1.2 As  shown,  all
varieties of sorghum and the less resistant varieties  of corn and
tomatoes are particularly susceptible to damage by  fluoride  ambient
air concentrations projected in the immediate vicinity of fertilizer
facilities (See Table 9-5).

2.5  THE EFFECT OF :.T-OSPHERIC FLUORIDES ON  MATERIALS OF CONSTRUCTION.
2.5.1   Etching of Glass2
     It is well known that glass and other high-silica materials
are etched by exposure to volatile fluorides like  HF and SiF4.    Some
experiments have been performed where panes of glass were fumigated
with HF in chambers.  Definite etching resulted from 9 hours ex-
posure at a level  of 590 ppb (270 ug/m3).   Pronounced  etching resulted
14.5 hours exposure at 790 ppb (362 ug/m3).   Such levels would, of
                               2-7

-------
                      Table 2-1.,EXAMPLES OF HF CONCENTRATIONS  AND  EXPOSURE  DURATIONS REPORTED
                                     TO CAUSE LEAF DAMAGE AND POTENTIAL REDUCTION  IN CROP VALUES
ro

C3
 Plant



 Sorghum


 Corn


 Tomato


Alfalfa
                 Concentration and Time*

Most sensitive varieties - most resistant varieties

0.7 ppb [0.32 ug/m3)  for  15 days  -  15 ppb  (6.9 »g/m3) for 3 days


2 ppb (0.92 ng/m3)  for  10 days    -  800 ppb (366 Mg/m3) for 4 hrs.

                                                     f\
10 ppb (4.6 yq/iii3 for 100 days    -  700 ppb (321 yg/m ) for 6 days



100 ppb (45.8 Mg/m3) for  120 days -  700 ppb (321 yg/m3} for 10 days
          Concentrations are expressed  In  terms of parts per billion (ppb) with the equivalent
           concentration expressed  in micrograms per cubic meter (ug/m3) given in parenthesis.

-------
course, cause extensive damage to many species of vegatation.   However,
ambient concentrations of this magnitude are improbable provided that
a fertilizer facility properly maintains and operates  some type of
control equipment for abating fluoride emissions.

2.5.2   Effects of  Fluorides  on Structures
     At the  relatively  low gaseous concentrations of fluorides  tn
 emissions  from  industrial  processes,  luuu ppm or less, tne damage
 caused by  fluorides  is  probably  limited mostly to glass and brick.
 Occasionally, damage  to the  interior  brick  lining of a stack has
 been attributed  to  fluorides.
     Considerable  experience is  available on  corrosion in  wet  process
 phosphoric acid  plants, where the presence  of fluoride increases  the
                                      3  5
 corrosive  effects  of  phosphoric  acid.     This experience  applies to
 the liquid phase;  the effects of fluoride air emissions need more
 study.   Entrained  crude phosphoric acid will  corrode  structural
 steel  and  other  non-resistant materials that  it settles on,  The
 corrosive  effects  of  "fumes"  from the digestion of phosphate rock
 have been  acknowledged  and good  design  and  maintenance practices
 for plant  structural  steel have  been  outlined.   More  information is
 needed about effects  of gaseous  fluorides in  low concentration  outside
of the mill.  It is usually  difficult to separate the  corrosive
effects  of airborne fluorides from those of other local and back-
ground pollutants.
                              2-9

-------
2.6   RATIONALE
      Based on the  information  provided  the  preceding sections of
chapter  2, it is clear  that fluoride  emissions  from phosphate
fertilizer facilities have  no  significant effect on human health.
Fluoride emissions,  however, do  have  adverse effects on livestock
and vegetation.  Therefore  the Administrator has concluded that
fluoride emissions from phosphate  fertilizer facilities do not
contribute to the endangerment of  public health.  Thus fluoride
emissions will be considered a welfare-related  pollutant for
purposes of section  lll(d)  and Subpart  B of Part 60.
2.7   REFERENCES

1.    Biologic Effects of Atmospheric  Pollutants; Fluorides.  National
      Academy of Sciences.   Washington,  D.C.  Contract No. CPA 70-42.
      1971.

2.    Engineering and Cost Effectiveness Study of Fluoride Emissions
      Control.  Resources Research  Inc.  and TRW  Systems Group.
      McLean, Va.  Contract  No. EHSD 71-14.  1972.  p. 5-1 to 5-11.

3.    Leonard, R.B.   Bidding to Bulk Corrosion in Phos-Acid Concentration.
      Chem. Eng. 158-162, June  5, 1967.

4.    Dell, G.D.  Construction  Materials for Phos-Acid Manufacture.
     Chem. Eng.  April 10, 1967.

5.   Pelitti, E.   Corrosion:   Materials of Construction  for Fertilizer
     Plants and Phosphoric Acid Service.  In:   Chemistry and Technology
                              2-10

-------
     of Fertilizers, Sauchelli, V.  (ed).   New York,  Reinhold  Publishing
     Corporation, 1960.   p.  576-631.

6.   Peletti, E.   Corrosion  and Materials  of Construction.  In:
     Phosphoric Acid,  Vol.  I,  Slack,  A.V.  (ed).   New York, Marcel
     Dekker,  Inc.,  1968.   p.  779-884.
                             2-11

-------
   3.   PHOSPHATE  FERTILIZER INDUSTRY ECONOMIC PROFILE AND STATISTICS
 3.1   INDUSTRY STRUCTURE
      The  phosphate fertilizer industry is a segment of the agricultural
 chemical  industry that is devoted to the production and marketing of
 commodities bearing the basic nutrients—nitrogen, phosphorous, and
 potash—for crop production.  From the perspective of end-use products,
 the scope of the agricultural chemical industry includes ammonia,
 ammonium nitrate, urea, ammonium phosphates, nitrophosphates, mixed plant
 foods  (in varying N-P-K combinations), superphosphates, phosphoric acid,
 and potash.  The phosphate production segment of the agricultural chemical
 industry begins with the mining of phosphate rock; proceeds with the basic
 chemical production of phosphoric acid and its subsequent processing to
 diammonium phosphate (DAP), superphosphoric acid (SPA), and triple super-
 phosphate (TSP); and culminates at the retailer level  where the numerous
 blends of fertilizers are formulated to satisfy the diverse interests of
 consumers.  There are three basic types of retailers - the granular NPK
 producers (manufacturers of chemical  formulations), the liquid fertilizer
manufacturers, and the mechanical blenders (dry bulk).  These groups compete
with each other in some markets (mixed fertilizers).
     The basic chemical producers in  the industry sell merchant phosphoric
acid and products derived from phosphoric acid, such as SPA,  DAP, and TSP.
NPK producers  can therefore buy from  a choice of raw materials to produce
a specific product.   For example, the typical  NPK plant operator can buy
DAP or produce it from wet-process phosphoric acid.  Therefore, some com-
petition can be expected among the various phosphate concentrates.
                             3-1

-------
     The  basic  chemical  producers, which  are  the focus of this
analysis,  are generally  not  identifiable  as single product firms.
Very few  firms  are  totally dependent on fertilizer production for their
business.  Most fertilizer production  is  conducted as a subsidiary
activity  in well diversified, often-times large, corporations.  These
firms are  chemical  manufacturers or petrochemical companies.  Some
companies  are farm  cooperatives, vertically integrated from production to
marketing, in geographic areas  in which they  are economically based.
These latter firms  are primarily engaged  in serving  farm customers by
retailing fertilizers, by purchasing and  shipping grains and other
agricultural products  to regional centers, and  by providing necessary
supplies  and services.  Finally, there are firms engaged in fertilizer
production that derive the main portion of their revenues from totally
unrelated activities,  such as  steel manufacture, pipeline construction,
etc.
     Generally, the basic chemical  producers  own the sources of
their raw  materials  (phosphate  rock mines).  According to 1970
production statistics, the ten  largest firms  in rock mining are ranked
as follows:
                             TABLE 3-1
               TEN  LARGEST PHOSPHATE ROCK PRODUCERS1
                                                     Production
           Firm                                   (1000 Short Tons)
International Minerals &  Chemicals                    8,000
Williams Co. (was Continental Oil Co.)                6,500
Mobil Chemical  Company                                5,900
Occidental Chemical  Company                           3,750
American Cyanamid Corp.                               3,650
U.S.S.  Agrichemicals                                  3,640
                                3-2

-------
                   TABLE 3-1 (CONTINUED)
                                                  Production
            Firm                               (1000 Short Tons)
Swift & Company                                       3,000
Texas Gulf, Inc.                                      3,000
Stauffer Chemical Company                             2,500
Gardinier, Inc.  (was Cities Service Co.)              2,000
     Total                                           41,940
     U.S. Production                                 50,640
     Percent of total production of ten largest
     fi rms                                              83%
     Based on the production of wet-process phosphoric acid, the
cornerstone of the basic chemical production in the phosphate fertilizer
industry, the ten largest firms in terms of 1972 production are as follows;

                           TABLE 3-2
             TEN LARGEST PHOSPHORIC ACID PRODUCERS2
                                                  Production Capacity
            Firm                                (1000 Short Tons  PpQ5)
CF Industries                                         880
Freeport Minerals Co.                                 750
Gardinier , Inc.                                       544
Farmland Industries                                   455
Beker  Industrial  Corp.                                411
Texas Gulf Inc.                                        346
01 in Corporation                                      337
W.R. Grace & Co.                                      315
U.S.S. Agri-Chemicals Inc.                            266
Occidental Chemical Co.                               247
     Total                                          4,551
     U.S. Production                                6,370
     Percent of total production of ten               71%
     largest firms
                            3-3

-------
     A  review of  the  above  tabulations  reveals  vertical
integration  from  the  mine through  the c*i°m-'c?1  "»r«Huction
within  several corporations.   Each of the precerilnn
phosphate  rock producers owns  basic  chemical production facilities
directly,  or through  equity interest in chemical producing companies.
CF  Industries and Farmland  Industries are integrated from the chemical
production stage  forward to the ultimate retailing of fertilizers.
Freeport Minerals is   strong  in ownership of sulfur reserves, an
important  raw material  for  production of phosphoric acid.  Beker
Industries is a newcomer into  the  fertilizer industry, as they purchased
the fertilizer assets  of Hooker Chemical (Occidental Petroleum) and El
Paso Products  Company.
3.2  EXISTING PLANTS
     The United States  is the  world's leading producer and consumer of
phosphate  fertilizer with an annual  consumption of nearly 20 percent of
the world's  total.   Phosphate fertilizers are  produced by several
processes  and consumed  in various  product forms.  Plant statistics are
available  for those processes  of interest under the following classifications:
wet-process  phosphoric  acid, superphosphoric acid, triple superphosphate,
and ammonium phosphates.
     Tables  3-3 through 3-6 list the company, location, year brought on
stream, and  annual production  capacity  of all wet-process phosphoric
acid, superphosphoric  acid, triple superphosphate, and ammonium phosphate
facilities in the United States.   Figures 3-1 and 3-2 show the geographic
distribution of these  plants.
                            3-4

-------
                                                   TABLE  3-3

                          PRODUCTION  CAPACITY  OF  WET-PROCESS  PHOSPHORIC ACID  (1973)
                                                                             4,5
CO
      Company
Allied Chen. Corp.
  Union Texas Petroleum Div.
    Agricultural Dept.

Arkansas Louisiana Gas Co.
  Arkla Chem. Corp., subsid.

Atlantic Richfield Co.
  ARCO Chem. Co., Div.

Beker Indust. Corp.
  Agricultural Products Corp.,
    subsid.
  National Phosphate Corp.,
    subsid.

Borden Inc.
  Borden Chem. Div.
    Smith-Douglass

CF Indust., Inc.
  Bartow Phosphate Complex
  Plant City Phosphate Complex
Location



Geismar, La.



Helena, Ark.


Fort Madison, Iowa



Conda, Idaho

Marseilles, 111.
Taft, La.
                                          Piney Point, Fla.
                                          Streator,  111.
                                          Bartow, Fla.
                                          Plant City, Fla.
                                                              Date on Stream         Annual  Capacity
                                                                                 {Thousands  of  Tons
1967



1967


1968



1972

1962
1965
1966
1953
1961
1965
160



 50


225



125 (adding 125)

105
185 (adding 30)
165
 25
650
250 (adding 375)

-------
co
i
O")
 Company

 Conserv  Inc.
 Farmland  Indust.,  Inc.
 Freeport  Minerals  Co.
  Freeport Chem. Co., Div.
 Gardinier, Inc.
 W. R. Grace & Co.
  Agricultural Chems. Group
 International Minerals and
  Chemicals Corp.
Mississippi Chem.  Corp.
Mobil Oil Corp.
  Mobil Chem. Co.
    Agricultural Chemicals, Div.
North Idaho Phosphate Co.
Occidental Petroleum Corp.
  Occidental  Chem.  Co., subsid.
  Occidental  of Florida Div.
  Western Div.
     TABLE, 3-3
    (CONTINUED)
Location

Nichols,  Fla.
Greenbay, Fla.
Uncle Sam, La.
Tampa, Fla.
Bartow, Fla.
New Wales, Fla.
Pascagoula, Miss.
Depue, 111.
Kellogg, Idaho
                                        White Springs, Fla,
                                        Lathrop, Calif.
Date on Stream

      1973
      1965
      1968

      1961
      1962

      1975

      1958

      1966

      1960
                              1966
                              1954
                                                                                             Annual  Capacity
                                                                                         (Thousands  of Tons
                                                                                                """"^™^^"^^^^^^^"^^™
150
500
750

490
315 (adding 250)
    (600)

130

130
 30
                                225  (adding  350)
                                 17  (adding  23)

-------
CO
I
      Company
01 in Corp.
  Agricultural Chems. Div.
  Indust. Products and Services Div.

Pennzoil Co.
  Pennzoil Chem., Inc., subsid.

Royster Co.

J. R.  Simplot Co.
  Minerals and Chem. Div.

Stauffer Chem. Co.
  Fertilizer and Mining Div.

Texas Gulf, Inc.
  Agricultural Div.

Union Oil Co. of California
  Collier Carbon & Chemical
    Corp., subsid.

United States Steel Corp.
  USS Agri-Chemicals, Div.

Valley Nitrogen Producers, Inc.
      The Williams Companies
        Agrico Chem. Co., subsid.
TABLE 3-3
(CONTINUED)
Location Date
Pasadena, Tex.
Joliet, 111.
Hanford, Calif.
Mulberry, Fla.
Pocatello, Idaho
Pasadena, Tex.
Salt Lake City, Utah
Aurora, N. C.
Nichols, Calif.
Bartow, Fla.
Ft. Meade, Fla.
Helm, Calif.
Edison, Calif.
South Pierce, Fla.
Dona Idsonvi lie, La.


on Stream
1965
1972
1968
1962
1966
1954
1966
1961
1964
1962
1959
1966
1965
1974


Annual Capacity
(Thousands of Tons ?£§)
230 (adding 14)
160
10 (adding 10)
140
145 (adding 80)
60
65
350 (adding 350)
8
95
190
35 (addinq 83)
8
280
(400)
                                                                                   TOTAL 6,453 (adding 2,690)

-------
                                              TABLE  3-4

                          PRODUCTION CAPACITY OF  SUPERPHOSPHORIC ACID  (1973) 4'5
CJ

00
      Company
      Allied Chem. Corp.
        Union Texas Petroleum Div.
        Agricultural Dept.

      Beker Indust. Corp.
        Agricultural Products Corp.
        subsid.

      Farmland Indust., Inc.
                                   Location
                                   Geismar, La.
                                   Conda, Idaho
                                   Greenbay,, Fla.
Internat'l  Minerals & Chem. Corp.  Bartow, Fla.
      North Idaho Phosphate Co.

      Occidental Petroleum Corp.
        Occidental Chem. Co., subsid.
          Occidental of Florida Div.

      J. R. Simplot Co.
        Minerals and Chem. Div.

      Stauffer Chem. Co.
        Fertilizer and Mining Div.
                                   Kellogg, Idaho

                                   White Springs, Fla.



                                   Pocatello, Idaho
                                   Pasadena,  Tex.
                                   Salt Lake  City,  Utah
Date on Stre<
1967
—
1971
1963
1967
1964
1966
1964
1966
im Annual Capacity
{Thousands of Tons P-Og)
127
45
138
52
87
139"
11
69
32 (adding 23)
22
34
Process &
Remarks3
submerged
combustion
vacuum
vacuum
vacuum: acid
Is redl luted
and used
captlvely to
make feed
phosphates
vacuum
submerged
combustion
vacuum
vacuum
vacuum

-------
                                                TABLE  3-4

                                               (CONTINUED)
Company
Texas Gulf, Inc.
  Agricultural Div.
Location
Aurora, N. C.
 Manufactured from wet process phosphoric acid
Date on Stream
     1967
     1970
      Annual  Capacity        Process &
(Thousands of Tons PO^C)     Remarks

          83                  vacuum
          83
         155" (adding 82)
                                         TOTAL
                                                                                          783 (addi nn 105)
  CO

  vo

-------
to

O
                                           TABLE 3-5

                      PRODUCTION CAPACITY OF TRIPLE SUPERPHOSPHATE (1973)
                                                                  4-7
        Company
Beker Indust. Corp.
  Agricultural Products
    Corp., subsid.

Borden Inc.
  Borden Chen. Dlv.
    Smith-Douglass

CF Indust., Inc.
  Plant City Phosphate
    Complex

Conserv Inc.

Farmland Indust., Inc.

Gardlnler Inc.
                             Location
                                     Conda, Idaho
Date on        Annual Capacity3
Stream    (Thousands of Tons Product)
1974-75
                                     Plney Point, Fla.    1966
                                     Plant City, Fla.     1965
                                     Nichols, Fla.

                                     Greenbay, Fla.

                                     Tampa, Fla.
        W. R. Grace & Co.            Bartow, Fla.
          Agricultural Chems. Group
(340)
                     70
                     530 (adding 400)
1973
1965
1952
1972
1954
1958
280
190
395
350
74T
390
275
55T
                  Product
                  Granular



                  ROP - granulate
                  portion of pro-
                  duction

                  ROP

                  Granular

                  ROP and granular



                  ROP and granular
                                     Joplln, Mo.
                                                  1953
                     100
                  ROP

-------
Company
Mississippi Chem. Corp.

Occidental Petroleum Corp.
  Occidental Chem. Co.,
    subsId.,
    Occidental of Florida
    Dlv.

Royster Co.

J.R. Simplot Co.
  Minerals & Chem. 01v.

Stauffer Chem. Co.
  Fertilizer & Mining Dlv.
Texas Gulf, Inc.
  Agricultural Dlv.
  USS Agrl-Chemicals, Dlv.

The Williams Companies
  Agrico Chem. Co., subsid.
Capacities are for gross weight.
TABLE 3-5
(CONTINUED)
Location Date on
Stream
Pascagoula, M1ss. 1972
White Springs, Fla. 1966
Mulberry. Fla. 1968
Pocatello, Idaho 1954

Salt Lake City, 1954
Utah
Aurora, N.C. 1966
Fort Meade, Fla. 1962
South Pierce, Fla. 1965


Annual Capacity9
(Thousands of Tons Product)
300
460
210
120

35
370 (adding 130)
295
600


Product
Granul ar
Granular
ROP
ROP- aranulate
portion of pro-
duction
ROP- granulate
portion of pro-
duction
ROP and granular
Granular
ROP- qranul ate
                                                          TOTAL   4,970   (adding 870)
• *W   *t I VII IV* I VL WW
portion of pro-
ductIon

-------
                                              TABLE 3-6

                          PRODUCTION CAPACITY OF AMMONIUM PHOSPHATES (1973)
                                                                    4-6
       Company
                                Location
                                                                                Annual  Capacity6
                     Date on Stream  (Thousands of Tons Product)   Remarks
CO
I

ro
Allied Chem. Corp.
  Union Texas Petroleum Div.
    Agricultural Dept.

American Plant Food Corp.

Arkansas Louisiana Gas Co.
  Arkla Chem. Corp., subsid.

Beker Indust. Corp.
  Agricultural Products Corp.,
  subsid.
  National Phosphate Corp.,
  subsid.

Borden Inc.
  Borden Chem. Div.
  Smith-Douglass

Brewster Phosphates

C F Indust., Inc.
  Bartow Phosphate Complex
  Plant City Phosphate Complex
Geismar, La.



Galena Park, Tex.

Helena, Ark.



Conda, Idaho

Marseilles, 111.
Taft, La.
                                       Piney  Point,  Fla.
                                       Streator,  111.

                                       Luling,  La.
                                       Bartow,  Fla.
                                       Plant  City, Fla.
                                                                 1967
150
DAP, leased to
Brewster
Phosphates
1966
1967
1972
1962
1965
1966
1965
1961
1974
175
150
270
200
395 (adding 70)
130
90
385
1,000
(390)
Mostly
DAP and
DAP
DAP
DAP
Mostly
DAP
DAP
DAP
mixtures
mixtures


mixtures



-------
CO

CO
Company
Conserv Inc.
Farmland Indust., Inc.

First Mississippi Corp.

Gardinier Inc.
W. R. Grace & Co.
  Agricultural Chems. Group
Internat'l Minerals & Chem.
  Corp.

Kaiser Steel Corp.
TABLE 3-6
(CONTINUED)
Location
Nichols, Fla.
Greenbay, Fla.
Joplin, Mo.
Fort Madison, Iowa
Tampa, Fla.
Bartow, Fla.
Bartow, Fla.
New Wales
Fontana, Calif.

Date on Stream
1973
1965
1954
1968
1959
1966
1962/63
1975
1955

Annual Capacity3
(Thousands of Tons Product)
200
390
245
495
525
235
50
(490)
25

Remarks
MAP
DAP
Mixtures
DAP and
Mixtures
DAP, MAP
DAP, MAP
Feed grade
DAP and MAP
DAP and MAP
Switches
                                                                                                          between
                                                                                                          ammonium sul-
                                                                                                          fate and DAP.

-------
CA.
I
-p.
                                                TABLE 3-6
                                               CONTINUED)
        Company
        Lone Star Gas Co.
          Nipak, Inc., subsid.
        Mississippi  Chem.  Corp.
        Mobil  Oil Corp.
          Mobil  Chem.  Co.
          Agricultural Chemicals Div.
                              Location
                              Kerens, Tex.
                              Yazoo City, Miss.
                              Depue, 111.
        Monsanto Co.                   Trenton,  Mich.
          Monsanto Indust.  Chems.  Co.
        North Idaho Phosphate Co.      Kellogg,  Idaho
Occidental Petroleum Corp.
  Occidental Chem. Co., subsid.
    Occidental of Florida Div.White Springs, Fla.
    Western Div.              Lathrop, Calif.
                              Plainview, Tex.
01 in Corp.
  Agricultural Chems. Div.    Pasadena, Tex.
Pennzoil Co.                  Hanford, Calif.
  Pennzoil Chem., Inc.  subsid.
        Royster  Co.
        J.  R. Simplot Co.
         Minerals and Chem. Div.
                              Mulberry, Fla,
                              Pocatello, Idaho
                    Annual  Capacity3
Date on Stream  (Thousands  of Tons Product)  Remarks
    1964                   no
    1958
    1966
                                                        1965
                                                                1966
    1973

    1968
    1961
 630
 240

40 - 45

  65
                           575  (adding  350)
                           165
                            25
                                                                                      800
Mostly mixtures

Mostly mixtures
DAP
                                             DAP,  MAP, and
                                             mixtures
 270
 190 (adding 50)
                                                                                                        Mostly mixtures
                                                                                                        Mostly mixtures
Mostly mixtures
PiAP
DAP
DAP and MAP

-------
CO

u
        Company

        Standard Oil  Company of Calif.
          Chevron Chem.  Co., subsid.
        Stauffer Chem Co.
          Fertilizer & Mining Div.

        Tennessee Valley Authority
Texas Gulf, Inc.
  Agricultural Div.

Union Oil Co. of California
  Collier Carbon and Chem. Corp.
  subsid.

United States Steel Corp.
  USS Agri-Chemicals, Div.
        TABLE 3-6
       (CONTINUED)

Location


Fort Madison, Iowa
Kennewick, Mash.
Richmond, Calif.

Pasadena, Tex.
Salt Lake City, Utah

Muscle Shoals, Ala.


Aurora, N. C.


Nichols, Calif.



Cherokee, Ala.
                                                                        Annual Capacity
                                                     Date  on  Stream   (Thousands of Tons Product)  Remarks
        Valley Nitrogen Producers, Inc.  Bakersfield, Calif.
                                         Helm, Calif.
          Arizona Agrichemical Corp.,    Chandler, Arizona
          subsid.
        The Williams Companies
          Agrico Chemical Co., subsid.
                                 Donaldsonville, La.
1962
1959
1957

1966
1965

1966


1966


1957



1962
                                                         1960
                                                         1959
                                                         1967
                        1969
200
 75
100

135
 65

 33


220


 55



245


 10
Mixtures
Mixtures
Mixtures

Mostly DAP & MAP
Mostly DAP & MAP

Solid ammonium
polyphosphates

DAP
Mostly mixtures
                                                                                                         DAP & mixtures
                                                                 8-24-0
                                                                           TOTAL
                                               140 (adding 150)   MAP & mixtures
                                                60               Mao, 16 - 20 -  0
                       700 (adding 840)  DAP

                    10,288 (adding 2,340)
        Capacities are for gross weight of product and includes diammonium phosphate (DAP),  monammonium phosphate  (MAP),
         ammonium phosphate sulfate and ammonium phosphate nitrate.

-------
   \
    \\1
    TW5^-
                       rlbUKt J-I

TRIPLE SUPERPHOSPHATE AND AMMONIUM PHOSPHATE PLANT LOCATIONS
                /  r
                /  >
                 fiSnTo
              LEGEND

• TRIPLE SUPERPHOSPHATE PLANT

A AMMONIUM PHOSPHATE PLANT
  (INCLUDES NITRIC PHOSPHATE
  PRODUCERS)
  TRIPLE SUPERPHOSPHATE AND SUPER-
  PHOSPHATE PLANT AT SAME LOCATION

-------
              / PSSBB-	
                                         FIGURE 3-2

                     WET-PROCESS AND SUPERPHOSPHORIC ACID PLANT LOCATIONS
                         pSSKS	J	
               LEGEND

A WET-PROCESS AND SUPERPHOSPHORIC
  ACID PLANT AT SAME LOCATION
• WET-PROCESS PHOSPHORIC ACID PLANT


-------
     As might be expected, the majority of the plants are located either near
the phosphate rock deposits of Florida, Idaho, and Utah; the sulfur  deposits
of Texas and Louisiana; or the farming outlets.
      As of 1973, there were 34 operating  wet-process  phosphoric acid
 plants with an annual  capacity of 6,435,000  tons  of P205;  10 super-
 phosphoric acid facilities with an annual capacity  of 783,000 tons of
 PoOcl 15 triple superphosphate facilities with an annual capacity of
 4,970,000 tons of product, and 44 ammonium phosphate  facilities with an
 annual capacity of 10,280,000 tons of product.     The production capacity
 attributed to wet-process acid plants in  Table 3-3  is about 80 percent
 of the total United States phosphoric acid production.  The balance is
 produced from elemental phosphorous made  by  the furnace method, which is
 not covered by  the standards  of  performance  for new stationary sources
 (SPNSSfr for the phosphate fertilizer industry.  Table 3-5  presents statistics
 for facilities  producing  both run-of-pile triple  superphosphate and granular
 triple superphosphate; it is estimated that  between 60 and 70 percent of
 the total capacity is associated with granular TSP.  Approximately 70
 percent of the production capacity of ammonium phosphates  listed  in
 Table 3-6 can be attributed to diammonium phosphate.

 3.3  CAPACITY UTILIZATION
      The phosphate fertilizer industry has  followed a cyclic  pattern
 of capital investment in new plants.  This  pattern  is demonstrated by
 the graphs for phosphoric  acid and ammonium phosphate production
 presented in Figures 3-3 and 3-4.  As shown in the graphs  by  the
 duration between peak utilization  (operating near 100 percent),  the
                            3-18

-------
cycle length appears to be 6 to 7 years.  During the 1965 to 1972 cycle,
expansion peaked in 1969.   Slackened demands  prompted price  cutting
and eventual temporary shutdown of some facilities.   At the  end of the
cycle, supply of plant capacity came    in balance with production.
     For additional insight into'the cyclic trend of capacity
utilization, Table 3-7 lists operating ratios for phosphoric acid and
diammonium phosphate production.

                              TABLE 3-7
               PRODUCTION  AS PERCENT OF CAPACITY8
Year
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
WPPA
100
92
80
77
69
84
96
96
89
89
83
82
DAP
72
63
66
56
54
78
96
96
—
—
—
~~
During mid-1973, the industry was  operating near capacity.   Idle
plants that had been shutdown during the 1968-1970 recession were being
refurbished for production.   Beker Industries is one example of a firm
that purchased idle phosphate facilities from petroleum companies for
acid and ammonium production.  New plant construction, as announced
                            3-19

-------
by Agrico Chemical  and  IMC, will not provide significant additions
to supply of phosphates  until  1975 or 1976.  By inspection of the
profiles in Figures  3-3  and 3-4 and the operating ratios presented
in Table 3-7, planned plant capacity for phosphoric acid seems
sufficient through  1976; ammonium phosphate capacity, on the other
hand, will have to  be increased to cope with the projected demand.
3.4  CONSUMPTION PATTERNS
     For an understanding of the historical consumption patterns of
WPPA, SPA, DAP, and  TSP, an overview of consumption of all phosphate
fertilizers is presented.  Although some superphosphoric acid is consumed
in the form of animal feed supplements, most phosphate production from
wet-process phosphoric acid ends up in fertilizers.
     Historical data are presented for U.S. consumption in Table 3-8.
Liquids and solids  (bulk and bagged) are all included in these data.
Total consumption includes phosphate values derived from wet-process
phosphoric acid to produce triple superphosphate, and phosphate rock
reacted with sulfuric acid to  produce normal superphosphate.
     Overall, the growth trend in total consumption has been at a rate
of 6.5 percent compounded annually from the base year 1960.  However,
normal superphosphate production has declined steadily from 1,270,000
tons (P205) in 1960  to 621,000 tons (P20g) in 1973.9 The gap in
phosphate values generated by  the decline in NSP has been mostly taken
up by diammonium phosphate production, as well as wet-process phosphoric
acid, the intermediate product.  Hence, consumption of wet-process
phosphoric acid and  diammonium phosphate production have grown at a
more rapid rate than total consumption of phosphates.
                               3-20

-------
•^  FIGURE 3-3.   CAPACITY UTILIZATION OF  WET-PROCESS  PHOSPHORIC  ACID10'11
                             	(.
                               rt.i~"~-
                             i;-.zn:"".:r.



                                        3^1	4Tt JTi--^-"--^ — p—114;


                                                     eoduetfon;
                                                            - Actual data


                                           3-21

-------
 ^^:r-.v IfcSSfe&ife^ii^^^^

FIGURE 3-4.   CAPACITY UTILIZATION  OF AMMONIUM  PHOSPHATES12



                      FT** r*T" -^r-r-r- • r-t-rr
                      iii 11 x-— . •'. --.- ——^—


                                  ...        ...-
                                 rittH.rtrja.iir.-.'f-^;-- - ht:t^-
                           3-22

-------
      The  two  other major categories presented in Table 3-8 separate
 the  basic chemicals that are applied directly to the soil from those
 that receive  further processing into mixtures; foods containing at least
 two  of  the nutrients basic to plant growth.  Some duplication of reporting
 is evident in the statistics as some undetermined amount appears twice,
 in "mixtures" and "direct applications".
      Review of  the data in Table 3-8 shows that the demand for
 normal  superphosphate has decreased drastically in recent years.
 During  this same time period, the use of ammonium phosphates (other
 than DAP)  and triple superphosphate have sftowed while the demand for
 DAP  has grown steadily.  Almost all direct application materials are
 now  DAP or GTSP.  Demand for these materials appears to have grown
 more rapidly than total consumption.  Additional factors contributing
 to this trend are the rise of bulk blending operations and intensive
 cultivation (emphasis on increased yield per acre).
     Fanners have lately realized that mechanical  blends of grandulated
 concentrates do just as well  as a grandulated, chemically produced
 NPK food and are available at lower costs.   A shift  from normal
 superphosphate and run-of-pile triple superphosphate production  to the
grandulated concentrates,  DAP, and GTSP, Is occurring.
      The  shift  in  product  usage has  also been accompanied by a  shift
 in raw  materials  for NPK plants.   Run-of-pile triple  superphosphate
 has  been  replaced  by wet-process  phosphoric  acid as a  raw material.
 Improvement in  phosphoric  acid  technology  has made  it  possible  to inhibit
 the  precipitation of impunities during  shipping, as most  NPK plants
 are  far removed from the areas of acid  production.
                            3-23

-------
                         TABLE 3-8.  U.S. PHOSPHATE CONSUMPTION,  1960-1973
                                          (1000 tons P0
Year

1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973C
Total
Consumption

2572
2645
2807
3073
3378
3512
3897
4305
4452
4666
4574
4803
4873
5072
Mixtures

2033
2069
2219
2474
2705
2816
3111
3503
3579
3724
3709
3943
4007
4200

Di ammonium
Phosphates
35
63
110
177
244
302
418
451
608
724
726
814
884
~
Direct Application
Normal
Superphosphate
103
100
97
98
93
95
94
86
79
72
62
55
44
35
Materials
Triple
Superphosphate
185
203
217
220
289
309
413
432
487
585
546
556
577
569

Ammonium b
Phosphates
171
188
205
205
216
204
221
224
227
207
184
179
174
-
ro
      alncludes  grades 18-46-0 and 16-48-0
      Includes  grades 11-48-0, 13-39-0, 16-20-0, 21-53-0,  and 27-14-0
      Preliminary

-------
     Consumption of superphosphoric acid is only recently  beginning  to
expand.  To date, it has been used primarily for the  production of liquid
fertilizers with some secondary end-use in the production  of animal  feed
supplements.  Data for consumption is limited.  Superphosphoric acid con-
sumption is currently estimated at only 15 percent of overall  phosphate
consumption.
     Several reasons are presented to explain the expected expansion .of
superphosphoric acid consumption.   Technology has made it  possible to
produce a product which eliminates the problems of sludge  formation en-
countered during shipping and storage of wet-process  acid.  Increased crop
yield per unit PgOg applied from liquid  fertilizers  has been claimed.
Transportation costs per ton of PJ^c are less for liquid  than for solid
fertilizers.
     The implications of the shifting patterns in the industry in
response to demands for cheaper, better quality products are as follows:
     1.  Granular concentrates will continue to expand in  production;
         these include DAP and GTSP.
     2.  Run-of-pile TSP production will decline and be replaced by
         GTSP and DAP.
     3.  Superphosphoric acid will have the largest growth rate of all
         phosphate commodities.

3.5  FUTURE TRENDS
     The phosphate fertilizer industry has experienced dynamic growth
in recent years.  Table 3-9 provides production statistics for wet
process phosphoric acid, triple superphosphate, and ammonium phosphates
                                  3-25

-------
                          TABLE  3-9

           U.S.  PRODUCTION OF THREE COMMODITIES IN THE
              PHOSPHATE  INDUSTRY, 1950-1973
Year
1950
1955
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
Wet Process
Phosphoric Acid
(Thousand
299
775
1,325
1,409
1,577
1,957
2,275
2,896
3,596
3,993
4,152
4,328
4,642
5,016
5,594b
5,621b
Triple
Superphosphate
tons of P205)
309
707
986
1,024
960
1,113
1,225
1,466
1,696
1,481
1,387
1,354
1,474
. 1 ,503
1,659
l,716b
Ammonia3
Phosphates
_
_
269
370
536
-
-
1,081
1,376
1,747
1,633
1,844
2,092
2,395
2,577
2,665b
 Includes diammonium phosphate, monammoniiim phosphate, ammonium
phosphate sulfate, ammonium phosphate nitrate, and other phosphate
fertilizers.


 Preliminary.
                             3-26

-------
from 1950 to 1973.   During this period,  wet-process  phosphoric  acid
has shown a strong  steady growth because of its  role as  an  intermediate
in the production of ammonium phosphates, triple superphosphate,  and
other phosphate products.  Production, of wet acid has grown at  an average
annual rate of 14 percent since 1960.  Table 3-3 lists announced  con-
struction of wet acid plants through 1975.   This new construction will
increase total  capacity by 41.6 percent.  An average annual growth rate
                                                            15
of ,6.0 percent is expected for the period from 1976  to 1980.
     Documentation  of superphosphoric acid production is very limited.
The usual reporting groups, such as Department of Commerce  and  TVA,  do
not report production figures.  The Fertilizer Institute reports
production in its Fertilizer Index but privately concedes that  its
published figures for the years of 1969-1971 are below estimates  of
actual production.
     A 40 percent saving in freight costs per unit weight of PgOg is
realized when phosphoric acid  is shipped in the concentrated super-
acid form.    Anticipated growth for superphosphoric acid is largely
due to this reduced shipping cost and  the availability of merchant
grade wet-process acid will be a major factor affecting expansion.  Announced
construction through 1975 will increase  existing capacity by approximately
13 percent.  Rapid  growth during the remainder of the decade is expected.
     By definition, ammonium phosphates  are products manufactured directly
from ammonia, phosphoric acid, and sometimes other acids, in contrast
to those ammoniated phosphates that are  produced in  NPK granulation  plants from
ammonia and run-of-pile triple superphosphate.  "Diammonium" phosphates
                             3-27

-------
include 16-48-0 (N, PgOg, and KgO content) and 18-46-0 grades.  Monam-
monium phosphates are 11-48-0.  These two generic products are produced
strictly from ammonia and phosphoric acid; other ammonium phosphates are
produced from a mixture of ammonia, phosphoric acid, nitric acid, and
possibly sulfuric acid.
     The growth of ammonium phosphates has been more rapid than that of
triple superphosphates - 20 percent annual growth since 1960 - because
of several inherent advantages of ammonium phosphates (see Section 4.4).
New construction through 1975 will increase production capacity by 22.7
percent.  Annual growth from 1975 to 1980 is projected at 6 percent.15
     Production of triple superphosphate has grown at an average annual
rate of 4 percent since 1960.  Triple superphosphate is produced by
two methods; the den method and the granulator method.  The den method
produces a material (run-of-pile) that is non-uniform in particle
size.  This material is stored, pulverized, and shipped to NPK plants
for ammoniation.  The granulator method produces a granular product that
is sold to bulk blender retailers for mixing or for direct application
(as a 0-46-0 fertilizer) to the soil.
     No statistics are available as to the breakdown of run-of-pile
versus direct granulator production.  In the industry, run-of-pile
production by the primary producer may be granulated and sold as GTSP
to bulk blender retailers as a direct application fertilizer.  Ultimately,
essentially all run-of-pile production becomes granulated, either by the
primary producer or by the NPK plant.  Only granulated TSP is expected
to be of importance in the future.
                                3-28

-------
     Announced new construction through 1975 will  result in a 17.4
percent increase in triple superphosphate production capacity, however,
this apparent growth does not take into consideration the possible
closings of existing run-of-pile facilities.  Granular triple super-
phosphate production should experience an average annual growth of 4
                          15
percent from 1975 to 1980.
     There appears to be a trend toward larger production facilities in
the phosphate fertilizer industry.  Average plant life is from 10 to 15
years and older plants are generally replaced by larger ones employing
the latest proven technology.  A number of small experimental plants
have been built that produce such products as ultraphosphoric acid (83
percent ^2^5)' ammoir>UIT1 polyphosphate (15-61-0, NPK content) and high
analysis superphosphate (54 percent ^2®$) l)ut t'11s experimental technology
has not yet been applied to large scale production.  All indications are
that the phosphate fertilizer industry will continue to grow rapidly
throughout the 1970-1980 decade.
3.6  PRICES
     Price competition in the fertilizer industry  has been very intense
historically because of the  large number of participants in all facets
of manufacturing—basic chemical producers, manufacturers of mixed
fertilizers, blenders, and  retailers.  No  one chemical  producer can be
said to  be a price  leader.   The participation of farm cooperatives in the
manufacturing  segment of  fertilizers, including the basic chemicals, un-
doubtedly has  been  a steadying  factor on prices, minimizing cyclic
fluctuations.
                               3-29

-------
     List prices are available for (agricultural grade) wet-process
phosphoric acid, triple superphosphate (run-of-pile and granular),
diammonium phosphate, and superphosphoric acid in the Chemical  Marketing
Reporter published by Snell Publishing Company of New York.  These
prices are not firm indicators of actual prices paid, however,  since
discounts, variability in credit terms to buyers, and service fees
combine to determine the realized price available to the producer.
     The long term profiles of wholesale prices for granular triple
superphosphate and diammonium phosphate are presented in Figure 3-5.
The estimates of prices realized by manufacturers are plotted against the
ranges of listed quotations for the same products for 1971 and  1972.
The spreads in prices reflect the difference in quotations by various
manufacturers at any given time.  No long term profiles of prices are
available for wet-process phosphoric acid, superphosphoric acid, and
triple superphosphate.
     July 1974 phosphate fertilizer list prices are presented in
Table 3-10.  The prices presented later in the text (Table 7-1) reflect
estimated averages for November 1974 developed from a more recent
economic study.  These averages reflect more closely prices realized
by the producers and will be  used in measuring the economic assessment
of emission guidelines  in Section 7.
                              3-30

-------
                    FIGURE 3-5.  WHOLESALE  PRICF.S  FOR TRIPLE SUPERPHOSPHATE AND DIAMMONIUM PHOSPHATE
  .
'   0
   S-
i   OJ
 —04
 -
  D.
   fO
   t/>
   QJ


...o
         40
          1964
— .
4
.

1 •
'
.... 	 J

1 • t
i ~~
•
965 ; 1
i
:

.._...;..... j-_ ...j ......
: i
! •
966 •• 19fe7 19
. - i... YEA


68 19
R '.'..'.

i .
i [
:
59. 19
. ..

. . . ! .
: | : i. . i
70 .19
:.. • i . : •

i
... !
7i: . i 19;
• ' • 1



-






| • • • 1 •' • 1 • • :
• i ! ! :
	 • • . i ; !

-------
       TABLE 3-10.  SUMMARY OF LIST PRICES AS OF JULY 1974 AND BASIS FOR PHOSPHATE QUOTATION19
I
o<
ro
Commodity
Wet-process phosphoric acid (WPPA)
Superphosphoric acid (SPA)
Diammonium Phosphate (DAP)
Run-of-Pile Triple Superphosphate
Granular Triple Superphosphate
Price
$ per actual ton)
$105
$150 - $158
S145 - $165
$38 - $86.50
$55 - $91
Production Quality
52-54% P205
7Q% P205
18%N
46% P205
I
46% P205 nin
46% P205 min
Quotation Basis
Delivered in Tanks,
F.O.B. Florida works
Same as WPA
Bulk Delivered, Railroad
car lots, F.O.P. Florida
Same as PAP
Same as DAP

-------
3.7  WORLD STATISTICS ON PgOg
     The levels of crop yields  per acre have greatly  increased  during
the past generation.   This increase has depended  upon the  generous
application of fertilizers containing  the elements  phosphorus,  nitrogen,
and potassium.  No two of these elements together could maintain  high
crop levels; therefore, plentiful  application of  P205 will  continue to
be necessary even to  maintain food production at  its  current level.
     Table 3-11 shows U.S. consumption of phosphate fertilizer-expressed
as P205 and the corresponding consumption for the entire world  is given
for comparison.  The  data from the reference are  adapted to this  table
and are rounded off.
     Phosphate fertilizer is made  almost entirely from phosphate  rock
and this is the only  practical  source  for the quantities required.
Table 3-12 shows the total known world  reserves of phosphate rock.
The United States has  30  percent of the  supplies which  are  considered
mineable and  beneficiable by current technology.  The Arab  Nations
possess 50 percent of world reserves and the Soviet  Union has  an
additional 16 percent.   It must not be  inferred that reserves  within
a country are uniform  in  quality; the higher grades  are mined  first, and
successfully  poorer grades follow at increased energy consumption  and
cost rates.
                            3-33

-------
                            TABLE  3-11
     UNITED  STATES AND  WORLD  CONSUMPTION OF PHOSPHATE FERTILIZER
Fiscal
Year           Consumption  of Phosphate Fertilizer Million Short Tons
                               U.S.                   World
1950                          1.950                    6.45
1955                          2.284                    8.33
I960                          2.572                   10.52
1965                          3.512                   15.03
1970                          4.574                   20.40
1975                          5.800*
'Estimated
                            3-34

-------
                         TABLE  3-12
         WORLD RESERVES OF PHOSPHATE ROCK 2°
    Country                         Million Short Tons
French Morocco                             23,500
U.S.                                       16,250
U.S.S.R.                                    8,500
Tunisia                                     2,240
Algeria                                     1,120
Brazil                                        670
Peru                                          500
Egypt                                         220
Togo                                          130
Spanish Sahara                                110
Islands - Pacific & Indian Ocean               45
Senegal                                        45
Other Countries                               800
                               3-35

-------
3.8   REFERENCES
 1.    Harre,  E.A.   Fertilizer Trends  1969.   Tennessee Valley
      Authority.   Muscle Shoals, Alabama.   1970.  p. 37.
 2.    David,  Milton L.t  J.M.  Malk,  and  C.C.  Jones.  Economic
      Analysis  of  Proposed  Effluent Guidelines for the Fertilizer Industry.
      Development  Planning  and Research Associates, Inc.  Washington,
      D.C.  Publication  Number EPA-230-1-73-010.  November 1973.  p.1-8.

 3.    Harre,  E.A.   Fertilizer Trends  1973.   Tennessee Valley Authority.
      Muscle  Shoals, Alabama.   1974.  p. 5,7.

4.    1973 Directory of  Chemical Producers,  United States of America.
      Stanford  Research  Institute.  Menlo Park, California.  1973.
      p. 417-418,  765-766,  860.
 5.    Osag, T.  Written  communication from Mr. T.A. Blue, Stanford
      Research  Institute.   Menlo Park,  California.  November 29, 1973.

 6.    Blue, T.A.   Phosphorous and Compounds.  In:  Chemical Economics
      Handbook.  Menlo Park,  Stanford Research Institute, 1973.
      p. 760.4003A - 760.4003E, 760.5003B -  760.5003K.

7.   Beck, L.L.  Recommendations for Emission Tests  of Phosphate
     Fertilizer Facilities.  Environmental  Protection Agency.   Durham,
     North Carolina.  September 28, 1972.   p. 12, 13,  16.
                              3-36

-------
 8.   Initial  Analysis of the Economic Impact  of  Water Pollution
      Control  Costs upon the Fertilizer Industry.   Development  Planning
      and Research Associates, Inc.   Manhattan, Kansas.   Contract No.
      68-01-0766.   November 1972.

 9.   Reference 3, p.  22.
10.   Reference 3, p.  16.
11.   Reference 2, p.  111-34.
12.   Reference 2, p.  111-38.
13.   Reference 3, p.  19.
14.   Reference 3, p.  21, 22.
15.   Bunyard, F.L. and P.A. Boys.   The Impact of New Source Performance
      Standards upon the Phosphate  Fertilizer  Industry.   Environmental
      Protection Agency.  Durham, North Carolina.   August 25, 1973.
16.   Striplin, M.M. Jr.  Production by Furnace Method.   In:  Phosphoric
      Acid, Vol. 1., Slack, A.V.  (ed).  New York,  Marcel  Dekker,  Inc.,
      1968.  p. 1008.
17.   Reference 2, p.  111-49.
18.   Chemical Marketing Reporter.   June 1971  through December 1972.

19.   Chemical Marketing Reporter.   July 22, 1974.
20.  Mineral Facts and Problems.   Bulletin 630.   United States Bureau
     of Mines.  1965.
                                  3-37

-------
                   4.   PHOSPHATE  FERTILIZER PROCESSES

 4.1   INTRODUCTION.
      The phosphate  fertilizer  Industry  uses phosphate  rock  as  its
 major raw material.   After  preparation,  the rock  Is used directly  1n
 the  production  of  phosphoric acid, normal  superphosphate, triple
 superphosphate, nitrophosphate,  electric furnace  phosphorous and
 defluorinated animal  feed supplements.   In addition to those products
 made directly from  phosphate rock, there are others that rely  on
 products prod.uced from phosphate rock as a principal ingredient.
 Figure 4-1  Illustrates the major processing steps used to transform
 phosphate rock  into fertilizer products  and Industrial  chemicals.
      The primary objective of the various  phosphate fertilizer processes
 is to convert the fluorapatite (Ca10(P04)gF2) in  phosphate  rock to soluble
 P205, a  form readily  available to plants.   Fluorapatite is  quite
 insoluble in water and, in most  farming  situations, 1s of little
 value as a  supplier of nutrient  phosphate.   The most common method
 of making the P205 content of phosphate  rock available to plants is
 by treatment with a mineral acid - sulfurlc, phosphoric, or nitric.
 Table 4-1 lists the available PgOg content of several  phosphate
 fertilizers.  Available P20g  is defined as  the percent soluble  PgOg
in a  neutral citrate solution.
                            4-1

-------
          FIGURE 4-1.   MAJOR PHOSPHATE ROCK PROCESSING STEPS
PHOSPHATE
ROCK
                 Defluorination
Grinding
                 Acidulation  (H2S04)
                 Acidulation  (HNO3)
                             Acidulation  (H3PO4)
Elemental
Phosphorus
                           Phosphoric
                           Acid
           Various
                                                      ANIMAL FEEDS
FERTILIZERS:
   Direct Application
   Normal Superphosphate
   Nitric Phosphates
   Triple Superphosphate
   Ammonium Phosphates
   Direct Application
INDUSTRIAL AND
FEED CHEMICALS
                                 4-2

-------
       TABLE 4-1.  P205 CONTENT OF PHOSPHATE FERTILIZERS2
   FERTILIZER                            PERCENT SOLUBLE
Normal Superphosphate                         16-22
Triple Superphosphate                         44 -,47
Monammonlum Phosphate                            5?.
D1 ammonium Phosphate                             46
4.2  WET PROCESS PHOSPHORIC ACID MANUFACTURE.
     Phosphoric add is an Intermediate product in the manufacture
of phosphate fertilizers.  It is subsequently consumed in the
production of triple superphosphate, ammonium phosphates, complex
fertilizers, superphosphorlc acid and dicalcium phosphate.
     Most current process variations for the production of wet-
process phosphoric acid depend on decomposition of phosphate rock by
sulfuric acid under conditions where gypsum (CaSO, • 2H20) is
precipitated.  These variations are collectively referred to as
dihydrate processes since the calcium sulfate is precipitated as
the dihydrate (gypsum).  Calcium sulfate can also be precipitated
in the semihydrate   (Ca SO^ • 1/2 H^O) and anhydrite (CaSO^) forms.
Processes which accomplish this are commercially less important than
the dihydrate processes, however, since they require more severe
operating conditions, higher temperatures, and a greater degree of control.
                         4-3

-------
     The overall reaction  In the dlhydrate  processes  is described by the
following equation.                                         (4-1)
            (P04)6 F2 + 30H2S04 + S102 + 58H20 * 30CaS04 '  2
     18H3P04 +
In practice, 93 or 98 percent sulfuric acid is normally used for
digestion of the rock.  Calcium sulfate precipitates, and the liquid
phosphoric acid 1s separated by filtration.
     Several variations of the di hydrate process are currently in use
by the phosphate fertilizer Industry.  The Dorr-Oliver, St. Gobain,
Prayon, and Chemico processes are among the better known designs.
Fundamentally, there is little difference among these variations -
most differences are in reactor design and operating parameters.
Figure 4-2 presents a flow diagram of a modern wet-process phosphoric
acid plant.
     Finely-ground phosphate rock is continuously metered
into the reactor and sulfuric acid  is added.   Because
the proper ratio of acid to rock must be maintained as closely as
possible, these two feed streams are equipped with automatic controls.
     Some years ago, plants were built with several separate reaction
tanks connected by launders, which are channels for slurry flow.  The
tendency now is to use a single tank reactor that has been divided
Into several compartments.  In most of these designs, a series of
baffles  is  used to promote mixinp of the reactants.
                            4-4

-------
-^
I
en
          • ASM
          NATCH
          GYPSUM
          POND WATER
         CTPJUM
         TO fOHO
                                                        •TO 5CRUB8ER
                                                                                       HTOROFLUOSILICIC AGO
                        FIGURE 4-2.   FLOW DIAGRAM ILLUSTRATING A WET-PROCESS PHOSPHORIC ACID PLANT

-------
    The single-tank reactor  (Dorr-Oliver design)  Illustrated in
Figure 4-2 consists of  two concentric cylinders.  Reactants
are added to the annul us  and digestion  occurs  in  this  outer compart-
ment.  The second  (central)  compartment provides  retention time  for
gypsum crystal growth aid prevents  short-circuiting of rock.
    The Prayon reactor  has been a widely used  design.  This process
variation involves the  use of  a rectangular, multicompartment  attack
tank - typically  10 compartments -  as  indicated in  Figure 4-3.  The
compartments are  arranged in two adjacent rows with the  first  and
tenth located  at  one end of  the reactor and the fifth and sixth at
the other.   In operation, digestion of the rock occurs in the  first
four compartments, the next  four provide retention time for the growth
of gypsum crystals, the ninth supplies feed for the vacuum flash
cooler,  and  the  tenth receives the cooled slurry from the flash
cooler  and  splits the flow  between the filter and a recycle stream.
                                            BAROMCTRIC
                                            CONDENSER


OCK

^1









\
^









1

V









:
> :






H

J

!






,sn


>
o










I
5



*


f
' II
FUME
1
r
**-* 4


1
_y

*
^»-
5

^


*

-]

ATE
|

1
TO
5EWI
L
5 ^



^
|
R

SCRUBBEI
:R
lr\
* 6


n
^SPLITTER
TANK

TO ^JL
STACK r 	 ^
FLASH
f COOLER
:M k -1
r^
Q COLO
^ SLURR
i^—
7 W fl ^^_
ATTACK TANKS (10)


f WEAK ACID
ZZVPjO,
                                                           TO
                                                          FILTER
                                         RECYCLE
                                       FROM FILTER
         FIGURE 4-3.  FLOW DIAGRAM FOR PRAYON REACTOR3
                                4-6

-------
      Proper crystal growth depends on maintaining sulfate ion
concentration within narrow limits at all points in the reaction
slurry.  The proper sulfate ion concentration appears to be slightly
more  than 1.5 percent.  Lower levels give poor crystals that are
difficult to filter; higher concentrations interfere with the reaction
                                                           4
by causing deposition of calcium sulfate on unreacted rock.
Good  reactor design will prevent sudden changes of sulfate ion concen-
tration, will maintain the sulfate ion concentration and temperature
near  optimum, and will provide sufficiently long holdup time to allow
growth of large, easily filterable crystals without the formation of
excessive crystal nuclei.
      Impurities In small amounts often have a marked effect on crystal
growth when they are present in a medium where crystallization Is
taking place.  Usually this impurity effect is detrimental.  Such
Impurities are likely to cause crystal fragmentation, small crystal
size, or a shift to needles or other hard-to-filter forms.
      Concentrated sulfurlc acid is usually fed to the reactor.  If
dilute acid is used, its water content must be evaporated later.  The
only  other water entering the reactor comes from the filter-wash
water.  To minimize evaporation costs, it is important to use as little
wash water as is consistent  with practical P205 recoveries.
     Considerable heat of reaction 1s generated in the reactor and
must  be removed.  This is done either by blowing air over the hot
slurry surface or by vacuum flash cooling part of the slurry and
                                 4-7

-------
sending it back  into the reactor.  Modern plants use the vacuum
flash cooling  technique illustrated in Figures 4-2 and 4-3,
     The reaction slurry is held in the reactor for up to 8 hours,
depending on the type rock and the reactor design, before being sent
to the filter.   The most common filter design in use is the rotary
horizontal til ting-pan vacuum filter shown in Figures 4-2 and 4-4.
This type unit consists of a series of individual filter cells mounted
on a revolving annular frame with each cell functioning essentially
like a Buchner funnel.  Figure 4-4 illustrates the operating cycle
of a rotary horizontal tiltinq-pan filter.
     Product slurry from the reactor is Introduced into a filter cell
and vacuum 1s  applied.  After a dewatering period, the filter cake
undergoes 2 or 3 stages of washing with progressively weaker solutions
of phosphoric  add.  The wash-water flow is countercurrent to the
rotation of the  filter cake with heated fresh water used for the
last wash, the filtrate from this step used as the washing liquor for
the preceding  stage, etc.
     After the last washing, the cell is subjected to a cake
dewatertng step  and then inverted to discharge the gypsum.  Cleaning
of the filter media occurs at this time.  The cell  is then returned
to Its upright position and begins a new cycle.
                              4-8

-------
                              CAKE WASHING
                                        CAKE OCWATERiNQ
                                                       FEED SLURRY
                                    CAKE DISLODGING
                                    AND DISCHARGING
     FIGURE 4-4.  OPERATING  CYCLE  OF  ROTARY HORIZONTAL
                      TILTING  PAN  FILTERS
     The 32 percent acid obtained  from the  filter generally needs
concentrating for further  use.   Current practice is to concentrate
it by evaporation in a two or three-stage vacuum evaporator system.
Wet process acid is usually not  concentrated above 54 percent, because
the boiling point of the acid rises  sharply above this concentration.
Corrosion problems also become more  difficult when concentration
exceeds 54 percent.  In the evaporator, Illustrated in Figure 4-2,
provision 1s made for recovery of  fluoride  as fluosilicic acid.  This
recovery feature is not necessary  to the evaporation and its
inclusion is a matter of economics.   Many evaporation plants have not
installed this device.
                           4-9

-------
     Table 4-2 shows a typical analysis of commercial wet-process
phosphoric acid.  In addition to the components listed in Table 4-2,
other trace elements are commonly present.  Impurities, those listed
in Table 4-2 as well as trace elements, affect the physical properties
of the acid.  Commercial wet-process acid has a higher viscosity than
pure orthophosphoric acid of the same concentration.  This tends to
increase the difficulty of separating the calcium sulfate formed
during acidulation of the phosphate rock.
                            TABLE 4-2
             COMPONENTS OF TYPICAL WET-PROCESS ACID7
Component
P2°5
CA
Fe
Al
Mg
Cr
V
H-O and other
Weight, %
53.4
0.1
1.2
0.6
0.3
0.01
0.02
37.56
Component
Na
K
F
so3
Si02
C
solid

Weight, %
0.2
0.01
0.9
1.5
0.1
0.2
2.9

                               4-10

-------
4.3  SUPERPHOSPHORIC ACID MANUFACTURE.
     Superphosphoric acid (also referred to as polyphosphoric acid)
is a mixture containing other forms of phosphoric acid in addition
to orthophosphoric acid (H3P04).  At least one-third of the P205
content of Superphosphoric acid are polyphosphates such as pyro-
phosphoric acid (H4P207), tripolyphosphoric acid (H5P301Q). tetra-
polyphosphorlc acid (HgP4013), etc.  Pure orthophosphoric acid
converts to polyphosphates when the P20g concentration exceeds 63.7
        Q
percent.   Concentrating above this level dehydrates orthophosphoric
acid to form polyphosphates.  Superphosphoric acid can have a minimum
of 65 percent PgOg which represents an orthophosphoric concentration of
just over 100 percent.  Commercial Superphosphoric acid, made by
concentrating wet-process or furnace orthophosphoric acid, normally
                                                  o
has a PgOg concentration between 72 and 76 percent.   Table 4-3 compares
the properties of 76 percent Superphosphoric acid to 54 percent ortho-
phosphoric acid.

   TABLE 4-3.  COMPARISON OF ORTHOPHOSPHORIC TO SUPERPHOSPHORIC ACID9
                                Orthophosphoric        Superphosphoric
                                     Acid                   Acid
Concentration of Commercial
Acid, % P205                             54                   76
H3P04 equivalent, %                      75                  105
Pounds P20g/gal                          7.1                  12.2
Percent of P205  as Polyphosphates        0                    51
Viscosity, CP
    at 100°F                             12                  400
    at 200°F                              4                   45
                             4-11

-------
      Superphosphoric  acid  has a number of advantages over the more
dilute  forms of  phosphoric acid, the foremost being economy In
shipping.   Since phosphoric acid of any concentration Is usually
transported at the same  price per ton, a 40 percent savings In freight
per unit weight  of P^Oc  results when superphosphorlc acid Is transported
                                   g
Instead of  ordinary phosphoric add.   Superphosphorlc acid may be
diluted to  orthophosphorlc acid at its  destination.
      In addition to freight savings, superphosphorlc acid offers
several other advantages.   It 1s less corrosive than orthophosphorlc
acid, which reduces storaae costs.  Finally, the con-
version of  wet-process acid has a special advantage.  Unlike furnace
acid, wet-process phosphoric acid contains appreciable quantities
of Impurities which continue to precipitate after manufacture
and form hard cakes 1n pipelines and storage containers.  When wet-
process acid 1s  converted  to superphosphorlc add, the polyphosphates
sequester the Impurities and prevent their precipitation.  Therefore
shipment and storage  of wet-process acid 1s far more attractive after
conversion  to superphosphorlc add.
     Two cornnerdal processes are used for the production of  super-
phosphoric  add:  submerged combustion and vacuum evaporation.  The
submerged combustion  process was pioneered by the TVA; dehydration
of the acid Is accomplished  by bubbling hot combustion gas through a pool
•of the acid.
                             4-12

-------
     The hot gases are supplied by burning natural gas in a
separate chamber.  The combustion gases are diluted
with air to maintain a gas temperature of 1700°F for intro-
duction into the acid evaporator.  Figure 4-5 depicts an
acid evaporator and Figure 4-6 the general process.  After
passage through the acid, the hot gases are sent to a sepa-
rator to recover entrained acid drpplets and then to emission
control equipment.
     Clarified acid containing 54 percent P?05 Is continuously
fed to the evaporator from storage, and acid containing 72 percent
PpOj- is withdrawn from the evaporator to product holding
tanks.  Cooling is accomplished by circulating water through
stainless steel cooling tubes in the product tanks.  The process
can be controlled by regulating the natural gas and air flows to
the combustion chamber, the dilution air to the combustion stream,
or the amount of acid fed to the evaporator.
      FIGURE 4-5.  TVA EVAPORATOR FOR PRODUCING SUPERPHOSPHORIC
                                  ACID
                             HOT
                            GASES
              CARBON
              INSERT
             AGIO
             FEED
                                          •- PRODUCT
                                          DISCHARGE
                            4-13

-------
   FUEL
TEMPERING
AIR
    AIR

               COMBUSTION
                CHAMBER
              EVAPORATOR
54°, CLARIFIED
    ACID

                                         SEPARATOR
                                          m
                                    WATER
                                                 r
                                                             CONTROLS
                                                             ACID MIST,  SiF,,
                                                             HF
                                              Fl'    722 ACID

                                               !
                                      PRODUCT'
                             WATER    STORAGE
                                           ACID COOLER
FIGURE 4-6.  SUBMERGED COMBUSTION PROCESS  FOR PRODUCING
                       SUPERPHOSPHORIC ACID
                            4-14

-------
      In addition  to  the TVA  process, a number of other submerged
 combustion processes have been developed.  Among them are the
 Collier Carbon  and Chemical  Process, the Albright and Wilson Process,
 the Occidental Agricultural  Chemicals Process, and the Armour  Process.
 The latter process produces  superpnosphoric acid of about 83 percent
 PgOj- which 1s  sometimes referred  to as ultraphosphoric acid.  The
 Occidental  and TVA  designs  are currently  in use in the United  States.
      Vacuum evaporation is by far the more Important commercial
 method for concentrating wet-process phosphoric acid to superphosphoric
 acid.  There are  two commercial processes  for the production of super-
 phosphoric add by vacuum evaporation:
      1.  The falling film evaporation process (Stauffer Chemical
          Co.)  and
      2.  The forced  circulation evaporation process (Swenson
          Evaporator  Co.).
 Feed acid clarification 1s required by both processes.  Clarification
 is usually accomplished by settling or by  a combination of  ageing  and
 settling.
      In general,  both processes are similar 1n operation.   Both use
 high-vacuum concentrators with high-pressure steam to concentrate  add
 to 70 percent  PpOg and both  Introduce feed acid into a large volume
 of recycling product acid to maintain a highly concentrated process
 acid for lower  corrosion rates.   In both systems, product acid
iis pumped to a  cooler before  being sent to storage or shipped.
      Figures 4-7  and 4-8 show the Stauffer and Swenson processes
 respectively.   The Stauffer  process adds 54 percent feed acid to
 the evaporator  recycle tank  where it mixes with concentrated product
                                4-15

-------
     FIGURE  4.7     STAUFFER EVAPORATOR  PROCESS
                                                         10
High-pressure
steam from
package boiler
    FALLING-FILM
     EVAPORATOR

Condensate,«	
to  package
steam boiler
     '.'.'el-process
     phosphoric
     ocid(S4%PzO,)
        Concentrated
              acid
                                        To ejectors
  FEED TANK
   EVAPORATOR
      RECYCLE
         TAMK
                                                BAROMETRIC
                                                CONDENSER
                             Superphosphoric
                             acid
                                 Coolant
                                 discharge
 Superphosphoric
 acid
(68-72%PtOj)
      FIGURE 4-8    SWENSON  EVAPORATOR PROCESS10
                                               TO AIR HECTOR
                                     VArnt
                                                                STOBACt
                         4-16

-------
acid.  This mixture Is pumped to the top of the evaporator and
distributed to the Inside wall of the evaporator tubes.  The
acid film moves down along the inside wall of the tubes receiving
heat from the steam on the outside.  Evaporation occurs and the
concentrated acid is separated from the water vapor in a flash
chamber located at the bottom of the evaporator.  Product acid flows
to the evaporator recycle tank and vapors to the barometric condenser.
To insure minimum PpOc loss, the separator section contains a mist
eliminator to reduce carryover to the condenser.
     The Swenson process, uses acid in the tube side of a forced
 circulation evaporator (Figure 4-8).  Feed acid containing 54 percent
 PpOg is mixed with concentrated acid as it is pumped into the
 concentrator system.  As the acid leaves the heated tube bundle
 and enters the vapor head, evaporation occurs and the acid disengages
 from the water vapor.  The vapor stream is vented to a barometric con-
 denser while the acid flows toward the bottom of the vapor hrad tank
 where part of it is removed to the cooling tank and the remainder is
 recycled to the tube bundle.
4.4  DIAMMONIUM PHOSPHATE MANUFACTURE.
     D1ammonium phosphate is obtained by the reaction of .ammonia
with phosphoric acid.  In addition to containing the available
phosphate of triple superphosphate, diammonium phosphate has the
advantage of containing 18 percent nitrogen from ammonia.
                         4-17

-------
      The  Importance  of di ammonium  phosphate  produced by wet-process
 acid has  increased as  it continues  to replace normal superphosphate as
 a direct  application material.  The shift to diammonium phosphate is
 most evident on  the  supply  side.  Ammonium phosphate production now
 exceeds 2.7 million  tons of PgOg a  year while normal superphosphate
 production has declined  32  percent  since 1968 to 0.6 million
 tons.   Increasing amounts  of diammonium phosphates are also being
 used in bulk blends  as  these Increase ir. popularity.
      The  increased use  of diammonium phosphate is attributable to
 several factors.  It has a  high water solubility, high analysis
 (18 percent nitrogen and 46 percent available P205)» good physical
 characteristics, and low production cost.  In addition, the phosphate
 content of diammonium phosphate (46 percent) is as high as triple-
 superphosphate, so by comparison, the 18 units of nitrogen can be
 shipped at no cost.
      The TVA process for the production of diammonium phosphate
 appears to be the most  favored with several  variations of the original
 design  now in use.  A flow diagram of the basic process is shown in
 Figure  4-9.
      Anhydrous ammonia and phosphoric  acid (about 40 percent P?0R)
are reacted in the preneutralizer using a NH~ / H,PO^ mole ratio
of 1.35.  The primary reaction is as follows:
      2  NH3 + H3P04 *  (NH4)2 HP04                                (4-2)

The use of a 1.35 ratio of NhL / H-jPO* allows evaporation to a water
                            4-18

-------
                                                                                                       TO AIR POLLUTION
                                                                                                       CONTROL SYSTEM
PHOSPHORIC
   ACID
                 r
                                                   AMMONIA, SiF4, HF

                                                       i  i
n
                                                  DRYER
                                                CYCLONES
                                                       V
7
   COOLER
   CYCLONES
        u
\\

3

-




! \



                                                          DRYER
AT'ONIA
  FLLD
                                                                                   SCREE:;
                                                                                         /\
                                                                                        ./  !
                                                                                                      PARTICOLATE
   i
^ /
OOVCRSIZE
     V'LL
                             FIGURE 4-9.  TVA DIAMMONIUM PHOSPHATE  PROCESS.

-------
 content  of  18 to  22 percent without  thickening of the DAP slurry to
 a  nonflowing  state.   The slurry  flows  Into  the ammoniator-qranulator
 and  is distributed over a bed  of recycled fines.  Ammoniation to the
 required mole ratio of 2.0 takes place in the granulator by injectinq
 ammonia  under the rolling bed  of solids.  It is necessary to feed excess
ammonia  to  the granulator to achieve a 2.0 mole ratio.  Excess
ammonia  and water vapor driven off  by the heat of reaction  are  directed
to a scrubber which  uses phosphoric acid as the scrubbing liquid.  The
ammonia   is almost completely recovered by the phosphoric acid scrubbing
liquid and recycled  to the preneutrallzer.  Solidification occurs
rapidly  once  the  mole  ratio has  reached 2.0 making a low solids recycle
ratio feasible.
     Granulated diammonium phosphate Is next sent to the drier,
then screened.  Undersized and crushed oversized material are
recycled  to the granulator.  Product sized material  Is cooled and
sent to  storage.
     In  addition  to  the TVA process, a single-step drum process
designed  by the Tennessee Corporation and the Dorr-Oliver granular
process  are used  for the manufacture of diammonium phosphate.  The
single step drum  process 1s  designed so that the entire neutralization
reaction  occurs in the granulator drum - phosphoric add 1s fed
directly  onto a rolling bed of fines while the ammonia 1s injected
under the bed.  In the case of the Dorr-Oliver design, a two-stage
continuous reactor is  used for the neutralization step.  The reaction
slurry 1s then combined with recycled fines in a pugmlll.
                           4-20

-------
4.5  TRIPLE SUPERPHOSPHATE MANUFACTURE  AND  STORAGE.
     Triple superphosphate* also referred to  as  concentrated
superphosphate, Is a product obtained by treating  phosphate rock
with phosphoric add.  According to the grade of rock  and  the
strength of add used the product contains  from  44 - 47  percent
available P205.
     Like diammonium phosphate, the Importance of  triple super-
phosphate has Increased with the declining  use of  normal super-
phosphate.  Triple superphosphate production  now Is around 1.7  million
tons of P205 which is more than double that of normal  super-
phosphate.11   It is used in a variety of ways -  large amounts  are
Incorporated Into high analysis blends, some  are ammoniated. but
the majority are applied directly to the soil.
4.5.1  Run-of-Pile Triple Superphosphate Manufacture  and Storaqe
    Figure 4-10 Is a schematic diagram  of the den  process  for  the
manufacture of run-of-pile triple superphosphate.   Phosphoric
add containing 52 - 54 percent P20g is mixed at ambient tempera-
ture with phosphate rock which has been ground to  about  70 percent
minus 200 mesh.  The majority of plants in  the United  States use  the
TVA cone mixer which is shown in Figure 4-11. This mixer  has
no moving parts and mixing is accomplished  by the  swirling action
of rock and acid streams introduced simultaneously into  the cone.
The reaction that takes place during mixing is represented by  the
following equation:
                           4-21

-------
         PHOSPHATE
            ROCK
PHOSPHORIC
   ACID_                           _	 T^CONTROLS
I
rv>
ro
                                                                        SiF4, PARTICULATE
                FIGURE 4-10, RUN-OF-PILE TRIPLE SUPERPHOSPHATE  PRODUCTION  AND  STORAGE

-------
Ca
       10
F2 + 14H3P04 + 10H2° •*  10CaH4(P04)2 *
                                                              2HF
     After mixing, the slurry is directed to a "den" where
solidification occurs.  Like mixers, there are a number of den
designs, one of the most popular continuous ones being the Broadfield.
This den is a linear horizontal  slat belt conveyor mounted on rollers
with a long stationary box mounted over it and a revolving cutter at
the end.  The sides of the stationary box serve as retainers for the
slurry until it sets up.

              FIGURE 4-11.  TVA CONE MIXER
                                              ClD LINC
                             4-23

-------
      The solidified slurry which exits from the den 1s not a
finished product.  It must be cured - usually for 3 weeks or more -
to allow the reactions to approach completion.  The final curing  stage
is depicted in Figure 4-10 by the conveying of product to the sheltered
storage pile.
 4.5.Z  Granular Triple Superphosphate Manufacture and Storage
      Two processes for the direct production of granular triple
 superphosphate will  be briefly presented.  A third process uses
 cured run-of-pile triple superphosphate, treats it with water and
 steam in a rotary drum, then dries and screens the product.   A
 large amount of granulated triple superphosphate is produced by
 this method but product properties are not as good as that
 produced by other processes.
      The TVA one-step granular process 1s shown in Figure 4.12.   In
 this process, phosphate rock, ground to 75 percent below 200 mesh,
 and recycled process fines are fed Into the acidulation drum along
 with concentrated phosphoric acid and steam.  The use of steam helps
 accelerate the reaction and ensure an even distribution of moisture in
 the mix.  The mixture is discharged into the granulator where solidifi-
 cation occurs, passes through a rotary cooler, and Is screened.   Over-
 sized material  Is crushed and returned with undersized material  to
 the process.  The reaction for the process 1s the same as that of
 ruh-qf-pile triple superphosohate.
                              4-24

-------
1 SiF4 *S1F4,
! i
W2lcK*TV 	 1 	 h 1 "CYCLED FINES !
\ — TS; — 7
.>/>/ 1 STEAM
CT _> i i
r-^C
sTEAM-n L-P- u.,.^1
ACIOUl ATIO^
PHOSPHOillC HtATCR OHUM
U(A] 1 — i 	 ~_
JMETER M— CONO
' 	 *ca
PUMP
^
SCREENS ^

i
^L
1
J
1
I 1
— r4-> 1
n_,
GliANULATOH |l
r"i
COOLER
l~ ~
/ 1 | OVE


RSIZE
— 1
	 r- — CAGE
FINES JL. MILL
&-O
ROLL 1 , f
CRUSHER
- •*
PARTICULATE
->S1F.t PARTICULATE
_ 	 >SU4. PARTICULATE
PRODUCT
1 	 to- TO
STORAGE
FIGURE 4-12.   TVA ONE-STEP PROCESS  FOR
           GRANULAR TRIPLE SUPERPHOSPHATE
                 4-25

-------
     The  Dorr-Oliver slurry granulation  process  is shown in
Figure 4-13.   In  this process,  phosphate rock, ground to an
appropriate fineness is  mixed with  phosphoric acid (40% P2°5) in a
series of mixing  tanks.   A thin slurry is continuously removed, mixed
with a large  quantity of dried, recycled fines in a pugmill mixer
(blunger), where  it  coats out on the  granule surfaces and builds up
the granule size.  The granules are dried,  screened, and mostly (about
80 percent) recycled back into  the  process.  Emissions from the drier
and screening operations are sent to  separate cyclones for dust removal
and collected material is returned  to the process.
     After manufacture,  granular triple  superphosphate 1s
sent to storage for  a short curing  period.  Figure 4-14 illustrates
the activities in the storage building.   After 3 to 5 days, during
which some fluorides  evolve from the  storage pile, the product is
considered cured and  ready for  shipping.  Front-end loaders move the
GTSP to elevators or  hoppers where  it is  conveyed to screens for size
separation.  Oversize material  is rejected, pulverized, and returned
to the screen.  Undersize  material  is returned tc the GTSP production
plant.   Material within  specification Is  shipped as product.
                           4-26

-------
      PHOSPHATE ROCK
i
ro
     PHOSPHORI-:: ACID
                                         S1F.
                                                                                                              TO  AIR POLLUTION
                                                                                                              C0.1TROL SYSTEM
                                                                      SiF4. PARTICULATE	Sii F4, PARTICULATE
                                                                   n
                                                             DUST   II   DRYER I
                                                           •CYCLONE,    CYCLONE
                                                                   -1         r •
                                                                   V         V
   OVERSIZE
   SCREEN
                                                    PUG LULL
                                                   GRANULATOR
                                                  (ROTARY TYPE
                                                   ALSO USED)
PRODUCT
SCREEN
              OVERSIZE
                WILL
             PRODUCT TO COOLING
                AMD STORAGE
                        ACIDULATORS
              FIGURE 4-13.  DORR-OLIVER SLURRY GRANUUTION PROCESS FOR TRIPLE  SUPERPHOSPHATE

-------
                                                         S1F4,  PARTICULATE
 i
rv>
CO
                    GTSP FROM
                     PROCESS
                                         ^'^-'^'-:^i-"';'^r'i'l'V''"'"^"'- • • ••''••'•
                                          STORAGE PILE ^'':',-"
                                                               "'
1


ce
0

A
SCREENS}
r
T1 »
MILLS
;
                                                                                  UJ
                                                                                  _l
                                                                                  LU
                                                                                                  SHIPPING
                        FIGURE 4-14.  GRANULAR TRIPLE  SUPERPHOSPHATE  STORAGE.

-------
4.6  REFERENCES
1.   Blue, T.A.  Phosphate Rock.   In:   Chemical  Economics  Hand-
     book.  Menlo Park,  Stanford  Research  Institute,  1967.
     p. 760.2011  F.

2.   Slack, A.V.   Fertilizers.   In:   Klrk-Othmer Encyclopedia  of
     Chemical Technology,  Vol.  9V  Standen,  A.  (ed).   New  York",
     John Uiley & Sons,  Inc.,  1966.   p. 100, 106, 125.
3.   Slack, A.V.   Dihydrate Processes  - Prayon.   In:   Phosphoric  Acid,
     Vol. 1, Slack,  A.V.  (ed).  New York,  Marcel  Dekker,  Inc.,
     1968.  p. 254.

4.   Noyes, R.  Phosphoric Acid by the Wet Process.   Park  Ridge,
     Noyes Development Corporation,  1967.  p.  10-11.

5.   Roos, J.T.  Commercial Filters  -  Bird-Prayon.   In:  Phosphoric
     Acid, Vol. I, Slack,  A.V.  (ed.).   New York, Marcel Dekker,
     Inc., 1968.  p.  446.
6.   Atmospheric Emissions from Wet Process  Phosphoric Acid Manufacture.
     National Air Pollution Control  Administration.   Raleigh,  N.C.
     Publication Number  AP-57.  April  1970.   p.  13-14.

7.   Reference 6, p. 11.

8.   Reference 4, p. 174.
9.   Striplin, M.M., Jr.   Production by Furnace Method.   In:
     Phosphoric Acid, Vol. I.,  Slack,  A.V. (ed.).  New York,
     Marcel Dekker,  Inc.,  1968.  p.  1008.
                               4-29

-------
10.  Reference 4, p. 222.

11.  Harre, E.A.  Fertilizer Trends 1973.   Tennessee  Valley
     Authority.  Muscle Shoals, Alabama.   1974.   p. 22.
                            4-30

-------
                       5.   EMISSIONS
 5.1   NATURE  OF  EMISSIONS.
     In assessing the environmental effect of the emissions from
 the  various  phosphate  fertilizer  processes,  fluorides  - which are  largely
 emitted  in gaseous  form, were considered  to  be the most significant
 and  were  chosen for regulation as  discussed  in Section 1.2.
     Gaseous fluorides emitted from phosphate fertilizer processes
are  primarily silicon tetrafluoride (SiF.) and hydrogen fluoride
(HF) .  The origin of these gases may be traced to the reaction
between phosphate rock and sulfuric acid represented by equation 4-1.
     3Ca1Q (P04)6F2 + 30H2S04 + Si02 + 58H20 -                 (4-1)
     30CaS04 • 2 H20 + 18 H3P04 + HgSiFg
     Under the existing conditions of temperature and acidity,
excess fluosilicic acid decomposes as follows:
                 H2S1F60)  * SiF4(g) + 2HF(g)                (5-1)

Actually, the mole ratio of hydrogen fluoride to silicon  tetra-
fluoride In the gases emitted  during the decomposition of phosphate
rock change with conditions (e.g., the amount of excess silica
                           5-1

-------
in the reaction mixture) and Is seldom equal to the stoichlo-
metric value.  At  high  levels of excess silica, the hydrogen
fluoride evolved will react to form silicon tetrafluoride according
to equation 5-2:
                 4HF +  Si02 -* SiF4 + ZHgO                     (5-2)

At low concentrations of silica* emissions will be rich in
hydrogen fluoride.
     Not all of the fluorides are driven off during the digestion
of the phosphate rock.  A certain amount is retained in the product
acid depending upon the type of rock treated and the process used.
These fluorides can be  emitted during the manufacture of super-
phosphoric acid, diammonium phosphate, or triple superphosphate.
     Fluoride emissions from superphosphoric acid and diammonium
phosphate processes depend solely on the fluoride content of the
feed acid.  In the manufacture of triple superphosphate, fluoride
emissions can also be attributed to the release of fluorides from
the phosphate rock.  Calcium fluoride and silica in the rock react
with phosphoric acid to form silicon tetrafluoride according to the
                  2
following reaction :

     2CaF2 + 4H3P04 + Si02 * SiF4 + 2CaH4(P04)2 • 2H20     (5-3)
     Scrubbing with water is an effective fluoride control technique
because of the high water solubility of most gaseous fluorides.
                              5-2

-------
This straight- forward approach 1s somewhat complicated, however,
by the presence of silicon tetrafluorlde. Silicon   tetrafluoride will
react with water to form hydrated silica (S1(OH)4) and fluosillclc
add (H2 SIFg) as Indicated by equation 5-4:
             3S1F4 + 4 H20 -•> 2H2S1F6 + S1(OH)4             (5-4)

Hydrated silica precipitates forming deposits on control equipment
surfaces which plug passageways and tend to absorb additional
silicon tetrafluorlde.  The nature of the precipitate, In the
presence of hydrogen fluoride, 1s temperature dependent.  Below
125°F, the precipitate is 1n the form of a gel.  Above this
temperature, 1t 1s a solid.   Control systems should be designed
to minimize plugging and to allow removal of silica deposits.
     Entrapment of scrubbing liquid must be kept to a minimum to
prevent the escape of absorbed fluorides.   Fluorides  can also
be emitted as parti cul ate from some fertilizer processes.
Particulate emissions can be effectively controlled by using
cyclones in combination wtth water scrubbers.

5.2  UNCONTROLLED FLUORIDE EMISSIONS.

5.2.1  Emissions from Wet-Process Phosphoric Acid Manufacture
     Fluoride emissions from wet-process acid  manufacture
gaseous silicon tetrafluoride and hydrogen fluoride.  The reactor
Is the major source of fluoride emissions from the process accounting
for as much as 90 percent of the fluorides emitted from an uncontrolled
                         5-3

-------
plant.   Additional sources are the filter, the filtrate feed and
seal tanks, the flash cooler seal tank, the evaporator system
hotwell, and the acid storage tanks.  Table 5-1 lists reported
emission factors for the various sources.  Fluoride emissions will  vary
depending upon the type of rock treated and the process used.
          Table 5-1  Fluoride Emissions from an Uncontrolled
                        Wet-Process Phosphoric Acid Plant4
            Source                   Evolution Factor
                                     (IbTF/ton Po(L
  Reactor                               0.04 - 2.2
   liter                                0.01 - 0.06
 Miscellaneous(filtrate feed and       up to 0.26
  seal  tanks,  hotwells, etc.)
      Modern reactors  emit fluorides  from  two  sources; the reaction
 vessel and the  vacuum flash cooler.  The  primary source is the
 reactor tank, where silicon tetrafluoride and hydrogen fluoride are
 evolved during  the digestion of the  phosphate rock.
      To prevent an excessive temperature  rise in the reactor, the
 heat of reaction is removed by cycling a  portion of the reaction
 slurry through  a vacuum flash cooler.  Vapors from the cooler are
 condensed in a  barometric condenser  and sent to a hot well while
 the non-condensables  are removed by  a steam ejector and also vented
 to the hot well.  This arrangement is illustrated in Figure 4-2.
 The majority of the fluorides evolved in the flash cooler are
 absorbed by the cooling water in the barometric condenser.  If air
 cooling  is  utilized,  fluoride  evolution can  be considerably areater
 than  indicated  in  Table 5-1.
                               5-4

-------
     The filter 1s the second largest source of fluoride emissions.
Most of the fluorides are evolved at the points where feed add
and wash liquor are Introduced to the filter.  These locations
are usually hooded and vented to the digester scrubber.
     A third source of fluoride emissions Is the multiple effect
evaporator used to concentrate the phosphoric acid from  30 percent
P205 to 54 percent PgOg.  It has been estimated that 20  to 40 percent
of the fluorine originally Introduced Into the process with the rock
Is vaporized during this operation.   Most of these fluorides are
collected 1n the system's barometric condensers.  The remainder
exit with the non-condensables and are sent to the hot well
which becomes the emission source for this operation.
     In the plant design Illustrated In Figure 4-2. the  vapor stream
from the evaporator Is scrubbed with a 15 to 25 percent  solution
of fluoslHcIc add at a temperature at which water vapor, which would
dilute the solution. Is not condensed.  The water vapor  1s then
removed by a barometric condenser before the non-condensables are
ejected from the system.  Almost all of the fluoride 1s  recovered
as by-product fluoslllclc acid.
     In addition to the preceding sources of fluoride emissions,
there are several minor sources.  These Include the vents from such
points as sumps, clarlflers, and acid tanks.  Collectively, these
sources of fluoride emissions  can be  significant  and  are  often
ducted  to a  scrubber.
                             5-5

-------
       Table 5-2  illustrates  a  typical material balance for the
  fluorine originally  present in  ohosohate rock.  It should be
  noted that the  results  in any given wet-orocess acid plant may differ
  considerably from  those shown in  the table.  Fluorine distribution
  will depend upon the type of  rock treated, process used, and kind of
  operation prevailing.
                             TABLE 5-2
        TYPICAL MATERIAL BALANCE OF FLUORIDE IN MANUFACTURE
                  OF WET-PROCESS PHOSPHORIC ACID
  Fluoride Input
I F/1QO I Feed  Rock
  Feed
  Fluoride Output
        3.9
  F/10C # Feed  Rock
  Product acid
  Gypsum
  Barometric condensers
  Air*
        1.0
        1.2
        1.67
        0.03
  Total
  *
        3.9
   Typical  emission from an uncontrolled plant.
     Fluoride-bearing water  from  the  barometric condensers as well as
the gypsum slurry is sent  to the  gypsum oond.  In the gypsum pond,
silica present in the soil converts hydrogen fluoride to fluosilicates
Limestone or lime may be added  to ponds to raise the pH and convert
fluoride to insoluble calcium fluoride.  Fluoride associated with the
gycsum slurry ->s already in  the insoluble forr-i before being sent EG
the oond.
                               5-6

-------
5.2.2  Lnissions fron Superphosc'-:oric Acid 'Manufacture
5.2.2.1  Submerged combustion process
     T!;e direct contact evaporator is the major source of fluoride
emissions from the submerged combustion process.  Fluoride
evolution is in tiie forn of silicon tetrafluoride and hydrogen fluo-
ride with a substantial portion ?s the latter.   The amount of
fluorides evolved will depend on the fluoride content of the feed
acid and the final concentration of phosphoric acid produced.  Feed
acid containing 54 percent P2r& has a typical fluoride content (as F)
of from 0.4 to 0.8 percent.
     Control of evaporator off-pases is complicated by the presence of
large amounts of entrained ohosphoric acid - amounting to as nuch as
                                                o
5 percent of the PgOg input to the concentrator.   /".n entrainment
separator is used to recover acid and recycle it to the process.  Some
entrained acid exits the separator, however, and tends to for?, a diffi-
cult to control acid aerosol.  The formation of this aerosol can be
minimized by reducing the temperature of the combustion oases before
                      g
they contact the acid.
     The acid sump and product Molding tank are secondary sources of
fluoride emissions from the submerged combustion process.  These
emission points are identified in Figure 4-6.  Uncontrolled emissions
from the submerged combustion process range frof 13 to 22 pounds of
fluoride per ton of P"- input.
                                5-7

-------
 5.2.2.2  Vacuur evaporation orocess
      Tlie ^aronatric condenser ,'ict^ell. tlio evaporator recycle tank,
 and the product coolino tank are  the  three sources of fluoride
 erissions from the vacuum evaporation nrooess.  These emission noints
 are identified in ^inures 4-7 ind ^-8.  "ost of the fluorides
 evolved during evaporation are absorbed by the cool in? v.-ater in the
 barometric condensers resulting in a  necjlicible emission to the
 atmosphere frorr this source.  Moncnndensables are elected fron the
 condenser systen and sent to the hotv/ell alono v/ith the :ondenser
 water.   This results in the hotwell beconino the naior source of
 emissions from the process.  The evanorator recvcle tank and the
 oroduct cooling tank are lesser sources of fluoride emissions.
 Total  erissions fron an uncontrolled  plant are estinated at 0.005
 oer ton P20g input.

 5.2.3   LITissions from Diamnoniun Phosphate Manufacture.
     Fluorides are introduced into the DAD nrocess with the wet orocess
 pliosp.'ioric acid feed and are also evolved frorr the c'losohoric acid
 scrubbing solution used to recover ammonia.  Wet process acid v/hic'i
 has  been  concentrated to 54 oercent PgCg typically contains n.l to 0.8
 percent fluorides  (as F) while filter acid (26-307. Pj/%.) v/ill  contain
 fron 1.8  to  2.0 oercent.  '      D1iosphoric acid ccntainin" about 4T
 percent f^Pr - obtained by nixir.n 5^ percent acid fron the 
-------
     "ajcr sources of fluoride em'ssions fron dirtT^oniu^ ohosnhnte
       include the reactor, "ranulatcr, dryer, cooler, screens and
pills.  Tho locations nf these emission points are de-Dieted in
Finure 4-9.  Ventilation streams .from these sources are corrhined
for nurnoses of control accordin" to the follnv.'ino scheme:  1)
reactor-oranulator cases, 2) drvsr qases, and 3) cooler an? screening
qases.
     Fluorides and arronia are the najor eniissions fro™ both the
reactor and the oranulator.  Reactor-oranulator rases are treated
for annonia recovery in a scrubber that uses ohosohnric acid as
tha scrubber liquid.  The phosohoric acid reacts with the ammonia and
the resulting product is recycled back to the process.  Flur-rides
can be strinoed fror the nhosrshoric acid and a secnndar' scrubber is
usually nauired for fluoride control.  Removal of evolved *lunridss
can be comolicated by their reaction with anmonia to forir a aarticu-
late.
     Drier emissions consist of ammonia, fluorides, and oarticulate.
Gases are sent through a cyclone for oroduct recovery before beinq
treated for armonia or fluoride renoval.  rddition?l fluorides csn
be striooed fron the ohosphoric acid scrubbing if arprni? recovery  is
practiced.
     Emissions from the screens, pills, and cooler consist orirarily
of oarticulate and ciaseous fluorides.   Ml gases are treated ^or
product recovery before enterinc ^luoride control enuiorient,   fvolutinn
of fluorides fror1 the oroducti^n nf c*iannr''oniui~ "'losoh^t?  is about 0.3
nounds of fluorides ^er ton of p pc fron tie reactor ?rd  r-rcinulatnr,
                              5-9

-------
and 0.3 pounds of fluoride ncr ton p-f D?n5 fror. the drver, cooler
            14
and screens.

5.2.4  Emissions from Triple Sun?rohosnhate 'Manufacture and ftorane

5.2.4.1  Run-of-nile triple sunernhpsnhate
     fluorides can be released fmn both the nhosnhnric acid gnd t
phosnhate rock durino the aciYulation reaction.  Maior sources
fluoride enissions include the nixinn cone, curinn belt (den),
transfer convevors. and storacie m'les.  These enission nrints
shown in fioure 4-10.
     The nixinn cone, curinn belt, and transfer convevors are tvnicallv
hooded with ventilation streams sent to a common ^luori^e control
system.  Storane 'ouildinns are usually sealed and ventilate^ bv
aonroxinatelv five air chanqes ner hour.    The ventilation stream
from the storage facilitv nav either be combined vnth the ^i
and den oases for treatment or sent to separate controls.
     Fluoride emissions are nrinarily silicon tetra^luoride -
35 to 55 oercent of the total fluoride content of the acid and rock
is volatilized as silicon tetrad uo ride.16  ^a*or sources o* fluoride
are the rr.ixina cone, curina belt, nroduct convevors. and stnrane
facilities.  Distribution of enissions anonn these sources will  v^rv
denendinn on the reactivitv nf the rock and the snecific oneratin" con-
ditions ennloved.  Emissions fron the cone, curinn belt, and con-
vevors can account for as nuch as 00 nprccnt nf VIP t^tcl 'lu^rides
released.    Conversely, it h?s  been claimed that annroxi'"3tel»' °°
                              5-10

-------
percent ?f '.he fluoride emissions from certain  ROP  olants  are  from
the storage area.   Emissions  from the  storage area  denend  on such
factors as the turnover rate  and the age and nuantity of PPP-TSP
in storage.
     evolution of fluorides from pnp-TSP production and  storage has
been estimated at 31  to 48 nounds ner ton of ^5-   This  estimate
is based on the follov/ing assumptions: 1) silicon tetra fluoride is
the only fluoride emitted in annreciable quantities and 2)  the feed
acid and rock contain typical  amounts of fluorine.

5.2.4.2  Granular triple sunerphosohate
Manufacture
     The major sources of fluoride emissions from granular triole
suoernhosphate plants usino the TV<\ one step process are the
acidulation drum, the granulat.or, the cooler, and the screening and
crushing operations.   Ma.ior sources of emissions for the Dorr-Cliver
process include the mixinq tanks, the blunger, the drier, and the
screens.  These emission ooints are indicated in Figures 4-12 and
4-13.  In addition to gaseous forms, fluorides are emitted as
parti cul ate from the granulator, blunger, dryer, screens, and mills.
     The acidulation drum and granulator (TVA orocess) and the
mixing tanks and blunger (Dorr-Cliver process) account for about 38
percent of the fluoride emissions, the drier and screens account for
                                                                 I g
50 percent, and the storage facilities account for the remainder.
It has been estimated that an uncontrolled production facility would
                                                                18
emit approximately 21 pounds of fluorides per ton of P2^5 i
                           5-11

-------
     Storage
     GTSP storage facilities can emit both particulate and oaseous
fluorides.  Uncontrolled emissions are estimated to be three pounds
                      1 o
per ton of PpOg input.
5.3  TYPICAL CONTROLLED FLUORIDE EMISSIONS

5.3.1  Emissions from Wet-Process Phosphoric Acid Manufacture
     Almost all existing wet-process phosphoric acid olants are equipped
to treat the reactor and filter qases.  A large number of installa-
tions also vent sumps, hotwells, and storage tanks to controls.
Typical emissions range from 0.02 to 0.07 pounds of fluoride per ton
of P«0c input, however, emission factors as high as 0.60 pounds fluoride
                                                                   in on
per ton PgOg have been reported for a few poorly controlled plants.   '
     It is believed that approximately 53 percent of the wet-process
add plants - accounting for 74 percent of the production caoacity  -
are either sufficiently controlled at present to meet the SPNSS
emission level of 0.02 pounds of total fluorides (as F) per ton of
PgOg input to the process or will be required to attain that level
by July 1975 to satisfy existing State regulations.  This estimate  is
based on the following:  1) all wet-process acid plants located in
Florida are required to meet an emission standard equivalent to the SPNSS
as of July 1975 and 2) all wet process plants built since 1967 are
assumed to have Installed spray-crossflow packed bed scrubbers or their
equivalent as a part of the original design.
                              5-12

-------
 5.3.2   Emissions from Superphosphorlc Acid Manufacture
     Two  types of processes are used for Superphosphorlc acid
 manufacture; the vacuum evaporation (VE) process and the direct
 contact evaporation  (DCE) or submerged combustion process.  Emissions
 from the  VE process, are very low in- comparison to the DCE process.
 Emissions from a VE process using a water actuated venturi to treat
 hotwell and product cooler vent gases have been reported to range
 from 4.1"X 10~4 to 15 X 10"4 pounds fluoride per ton P205 input.21
 However, uncontrolled emissions from this process are also less than
 the 0.01 pound per ton of P20g input emission guideline.
 Since most of the existing superphosphoric acid plants use the VE
 process, approximately 78 percent of these plants are currently
 meeting the emission guideline,
     Since the DCE process has much higher emissions, the emission
 guideline was established at 0.01 Ib.  F/ton P205 input.
 This guideline 1s consistent with the  level of emission control
 achievable by application of best control  equipment to a DCE process.
 Typical controls used are a primary scrubber for removal of entrained
                                                               99
 acid and one «r more additional scrubbers  for fluoride control.
 Emission from an existing facility weee reported at 0.12 pounds
 fluorl* per ton
6.3.3  Emission* fn» 01 ammonium Phosphate Manufacture
     Most existing plants are equipped with ammonia recovery
scrubbers (venturi or cyclonic) on the reactor-granulator and
drier streams and participate controls (cyclones or wet scrubbers)
on  the Cooler stream^  Additional, scrubbers for fluoride removal  are
lUNUfl,  but not typical.  Only about 15-20 percent of the instal-
lations  contacted by EPA during the  development of the-SPNSS were
                            5-13

-------
equipned with spray-crossflow packed bed scrubbers or their eauiva-
lent for fluoride  removal.   Fluoride emissions ranoe fro"! 0.0? to 0.5
                                                                  2/i
oounds per  ton  P-Cg  deoendino uoon  the decree of control orovided."
5.3.4  Emissions from  Triple Superphosphate Manufacture and Storage

5.3.4.1  ROP  triple  superphosphate  (manufacture and storage)
     All run-of-pile triple  superphosphate production facilities and
70 percent  of the  storage  facilities are eouioped with so^e *orw o^
        25
control.    Emissions  from those  slants which control bo^h nrcduction
and storage areas  .an  ranqe  from  0.2 to 3.1 pounds of -fluoride ner
                                                                pc ?7
ton of P20g innut  dependina  unon  the dearee of control orovideri. "
Plants with uncontrolled storaoe  facilities could emit as puch as 12.7
oounds of fluoride oer ton of Pp^g  inout.  "t least 6? oercent o^ ts.e
industry will be reauired  to meet State emission standards equivalent
to the SPNSS  by July 1975.

5.3.4.2  Granular  triple superphosphate  (manufacture)
     Existing State  regulations will require 75 oercent of the industry
to neet an  emission  standard of 0.20 pound fluoride per ton Pg0^ bv
July 1975.  Emission factors for  the industry ranoe fror 0.20 to 0.60
                     op
nounds per  ton  P2^5-
5.3.4.3  Granular  triole suoerohosphate  (storaoe)
     Aooroxinately 75  oercent of  the r*TSP  storaoe facilities ere
                                                 23
thought to  be equipped with  some  ^errr  of control. ''   Poorlv con-
                                                -d
trolled buildinns  can  release as  nuch  as 15 x  10   oounds of
fluoride  per hour per ton of P-,' 5 in stor^ce  '   V-'ell-ccntrn'Med
                                                            -4
storage facilities can reduce emissions to less  than 5 x  10   nounds
                              5-14

-------
                                               on
 fluoride per hour per  ton of  P2^5  in  storage.     It  is estimated
                                        p
 th?.t 33 oercent of  the  controlled  bin'ldinos could reet fnf!SS  °n'ssion
       20
 level.
  5.4   GYPSUM POND EMISSIONS
       .', wet  process  phosphoric  acid  plant  produces gypsuT  in  slurry
  forn, according  to  the cherrical  reaction  indicated  in equation  4-1.
  The reaction also volatilizes  fluorides which are largely absorbed
  in scrubber and condenser water  and is then sent with the qt'osum  to
  large storage ponds, known as oypsun ponds or "gyp" conds.   nver  7^
 percent of the fluorine content  of the rock used in the wet-acid
 process may pass over to the gyp pond.  If the same plant also  pro-
 duces DAP or TSP, a larga part of the fluorine content of the phosphoric
 ecid will also pass to the gyp pond through the use of water scrubbers
 in these additional  processes.   Thus,  85 percent or more of the fluo-
 rine originally present in the phosphate rock may find its way to the
 gy? pond.
      T;,2  water of the  gyp pond is normally acic1,  Kavir.a  a  pH ar-u.n'
 1.5.   This acidity is.probably  due to  inclusion  of phosphoric acid in
 the -..ashed gypsum from  the gyr»sm« filter.   It  is  impractical  to  remove
 ell of the acid from the  filter cake by washinn.   For  this  reason,
 ?yo ponds around  the country have bee.i found to have a fluoride  concen-
 tration of 2000-12,500 ppm.31"34   The fluoride concentration  of  a  given
 oond does not continue rising,  ;--jt tends to stabilize.   Tin's  nay te
 c!u£ to orecinitation cf co— !•};• c-lcium silicofluorides  in the ocnd
 ./at&r.    Tfiare /ould oe an equilibrium invclvin"  tiipse  conlexes,
iiydrogen ion, and soluble or volatile dissolved fluorides.
                                5-15

-------
      It  has  been observed that the  above  concentrations of fluoride
exert  a  partial  pressure out o* OVP onnd  water anc1  that volatile
fluorides  tend to evolve fror ayp ponds.   Based on  wet orocess
Dhoso.horic acid  production.  plants  have pyo  oonds of surface areas
in the ranoe of  0.1-0.4 acres per daily ton  of ?2f5-34  This reans
that a large plant may have  a CJVD pond vn'th  surface area of 200 acres
or more.
     Emission factors  have been estimated, measured and calculated for
ayp ponds.   These factors vary from about 0.2 to 10 Ibs F/acre dav.?1~*?/!
     The most comprehensive  work on ovp oond emission ^actors is that
recently done in EPA Prant No. R-800950.     The experimental and
mathematical  procedures are  quite detailed and the  entire report should
be examined  by those needinn to understand the methods user!.  The
partial pressure of fluorides out of actual  oond water was deterrined
in the laboratory.   The evaporation rates of dilute fluoride solutions
were derived from known data ^or flat water  surfaces, usinn established
mass transfer principles.  Also, ambient  air fluorides were measured
downwind of  the  same gyp oonds which Burnished the  above water samoles
for fluoride partial oressure measurements.  Finally, the contribution
of the gyp pond  to the fluoride peasurenent  at the  downwind sensor
was calculated,  usina  a variant o^  the Pasauill division eauation.
The source strength in this  eouation was, of course, calculated
with the partial  pressure data and  mass transfer coefficient previouslv
develooed.   There were a total  of 95 useable downwind peasure^ents for
                             5-16

-------
 two  nond  sites,  and  the  estipated  and  the neasured downwind  fluoride
'concentrations showed  need  frree^ent.   The  calculated  v?lue  *f  the
 arbient air  fluorine concentration downvind of  the oonri -,'?s  fnunH
 to be  statistically  the  sane  as  the.neasured value.
     Tone emission factors  fro**1  the above  investication ere  niven  in
 Table  5-3.   Data at  other temosratures mav  be found  in the orim'nal
 reference.
 Table  5.3   FLUORIDE EMISSION FACTORS  FOR SELECTED RYP.SU''1
                        90°F;  IDs/acre  day.3*
                                    Nind velocity
                                 at 16 ft elevation,
                                      m/sec
1 2
fond 10 0.8 1.3
6/00 pprn F
Pond 20 0.8 1.3
12,000 pir F
4 P
2.3

2.3 3.2

      For the two plants studied, the emission rates were nearlv
 identical.   There r,ay be significant differences if other oonds are
 considered, but more neasurenents would be required to establish this.
      The most effective v/av to reduce fluoride evolution fror nvn oonds
 vould be to reduce their fluoride oartial pressure in sone way.  The
 nost effective nethod now knovn v/ould be liruina, to raise the nH.
 Lininq to a pH of 6.1 has redo:ed the nartial oressure of fluoride 30-
 fold.31  The indicated li>e cost -.-ould bs hi oh for the case described,
 but this cost can be reduced i* ? rethod can be *ound to reduce
 pnosnhoric acid loss to the nvp pond.
                            5-17

-------
5.5  REFERENCES

1.   Teller, A.J.  Control of Gaseous Fluoride Emissions.  Chsrical
     Engineer! no Proqress.  63! :  75-79, March 1967.

2.   Lutz. W.A. and C.J.  Pratt.  Kanu^actiire of Triple Smerohcsnhate.
     In:  Chemistry and Technoloay of Fertilizers. Sauchelli, V. (ed.)
     New York, Reinhold Publishing Corporation, 19fQ.  D. 175.
3.   Teller, A.J.  and  D.  Reeve.   Scrubbing of Gaseous F.
     In:  Phosphoric acid,  Vol.  I,  Slack, A.V.  (ed.).  F!ew Yori-,
     ?iarcel Dekker,  Inc., 19F8.   p.  752.
A.   Engineer! nq  and Cost Effectiveness  Study of  Fluoride Enissions
     Control.   Resources  Research,  Ire.   McLean,  Viroim'a.  rD/1
     Contract  EHSD 71-14.  January  1972.  p. 3-152.
5.   Atmospheric  Emissions from Het-Process  Dhosohnric ^cid Manufacture.
     National  Air Pollution Control  Administration.   Paleinh, north
     Carolina.   Publication Number AP-57.   Aoril  1970.   p. 1C.
6..   Control  Techniques for cluoride Enissions.  Environmental  Health
     Service.   Second  Draft.  September 1970.   p. 4-71.   (Unoublished).
7.   Noyes, R.  Phosphoric Acid by the Met Process.   park Hidoe,
     New Jersey.   Koyes Development Corporation,  1957.   o. 2?^t
     231.
                                5-18

-------
 P.    Scott,  W.C.  Jr.   "reduction  by  Vet  Process.   In:
      P.'sosohoric  Acid,  Vol.  !.  Slack. A.V.  (ed).   fie-.'  YO-I-,
      •iarcel  Dehker.  Inc.,  1968.   D.  1080.

 ?.    reference 7, D.  191 .

10.    Reference 5, p.  4-71.
11.    Air Dollution Control  Technolociy and Costs in Seven Selected
      /Teas, Phase I.   Industrial  r^s Cleaninn Institute,  ^tan^ord,
      Connecticut.  EPA Contract 63-02-0289.  '.arch 1973.  P. 86.

12.    Reference 7, p.  256.

13.    reference 6, p.  4-106.

14.    Reference 4, p. 3-161.
15.    Tin'berlake,  R.C.  Fluorine  Scrubber.   Southern  Fnnineer.
      June  1967.   p. 62-64.
 16.   Jacob,  K.D.  et al.  Comoosition and  Pronerties  of Suierohosohf»t<5,
       Ind.  and Ena. Chem. _34_:   7*7.   June

 17.    Reference  2, o.  180.

 18.    Reference  4, o.  3-167.

 19.    Referen- ••  5, D.  3.
                                5-19

-------
20.   Technical Report:  Phosohate Fertilizer Industry.   In:   An
      Investigation of t'ie Pest cystens if Erission. "aduction  *or  "i/
      Phosphate Fertilizer Processes.  Environmental Protection  "nenc".
      Research Triangle park, North Carolina.  .April 197*.   n. 22.

21.   Reference 20, o. 33.
22.   Reference 6. p. 4-74.
23.   Good/in, D.  Written corrmunication fro^ *1r. ^.D. frith,  Acci-
      dental Chenical Conpany.  Houston, Texas,  /ioril 3"),  1973.
24.   Reference 20, p. 36, 38.

25.   Beck, L.L.  Reconmendations for  Emission Tests ^f phosnhate
      Fertilizer  Facilities.  Environmental  Protection ftnencv.
      Durham.  North Carolina.  September 28, 1972.  o. 1^-16.

26.   Reference 20, p. 47.

27.   Reference 4, p. 3-1C7.

28.   Reference 20, o. 52, 53.
29.   Reference 25, D. 10-13.

30.   Reference 20. o. 57.

31.   Reference 5. on. 15-16.
                             5-20

-------
32.   Tatera, B.J.   Parameters  '.-:hich Influence Fluoride Erissions  from
      Synsun Donds.   D;-iD  Thesis.   University c-f Florida, <-?ir.=svillc.
      1973.  (University  •-icrofilr-s. "nn ,'rjor, 'iicr.., liur.ber 71-275.)

33.   Elfers, L.A.,  IIAPC'.,  to ^, .\J. and Crane, G.B. cistec!
      Decerbsr  31, 1968.   Fluoride .-nalyses of Gyp Pond Hater from
      Texas Gulf  Sulfur Corporation.

34.   Kino. h'.R.   Fluorine  -r-ir Pollution from Wet-Process  Phosphoric
      ,"cid Plant  Process  -  "ater Ponds.  TIO T'-.esis.  north  Carolina
      State University. !>lein:i,  -.r-. K71, st'-jported bv EP,n. Research
      Grant i;o.  1-800950.
35.   Teller, /"-.J.   Communication at fAPCTAC msetinci in '-.aleiah, r.'.C.
      on  February 21, 1373.
                           5-21

-------
 6.  CONTROL TECHNIQUES FOR FLUORIDES FROM PHOSPHATE FERTILIZER PROCESSES
 6.1  SPRAY-CROSSFLOW PACKED BED SCRUBBER
 6.1.1  Description
     The spray-crossflow packed bed scrubber has been accepted for
 several years as the most satisfactory fluoride control device available
 for wet-process phosphoric acid plants.1  Most wet-process acid plants
 built since 1967 probably have installed this scrubber as part of the
 original design.  During this same time, however, the spray-crossflow
 packed bed design has seen less general use in processes other than wet
 acid manufacture.  The reluctance of the fertilizer industry to fully
 adopt the spray-crossflow packed bed scrubber can be traced primarily
 to concern about its operational  dependability when treating effluent
 streams with a high solids loading.  Such effluent streams can be
 handled by placing a venturi  scrubber in series with and before a spray-
 crossflow packed bed scrubber; the EPA has tested a number of DAP and GTSP
 plants having this dual  scrubber arrangement.   Also, improvements in spray-
 crossflow packed scrubber design have alleviated the initial problem of
 plugging and allow a greater solids handling capacity.   The development
 of stricter fluoride emission standards should provide  incentive for more
 widespread use of this scrubber design.
     Figure 6-1  is a diagrammatic representation of the spray-crossflow
 packed bed scrubber.  It consists of two sections - a spray chamber and
a packed bed - separated by a series of irrigated baffles.  Scrubber
size will  depend primarily upon the volume of  gas treated.  A typical
unit treating the effluent streams from a wet  acid plant (20,000 scfm)
is 9 feet wide,  10 feet  high, and 30 feet long.2
                              6-1

-------
         PRIMARY  GAS  INLET
en
i
rxj
                                               POND WATER
                                                    V
                                                    I!



1





i
xU SECONDARY
r^\^f

V




GAS INLET


SPRAYS
                                                    CQ

                                                    Q
                                                    LU
                                                    f—
                                                    
-------
      All  internal  parts  of the  scrubber  are  constructed of
 corrosion resistant  plastics  or rubber-lined steel.  Teflon can  be
 used for  high  temperature  service.  General  maintenance consists
 of replacement of  the  packing once, or twice  a year.  Exoected life
 of the  scrubber is 20  years.
      Both the  spray  and  the packed section is equipped with a aas
 inlet.  Effluent streams with relatively hioh fluoride concentrations -
 particularly those rich  in silicon tetrafluoride - are treated in the
 spray chamber  before entering the packing.   This preliminary scrubbing
 removes silicon tetrafluoride thereby reducing the danger of plugaino
 the  bed.   At the same  time, it  reduces the loading on the packed staoe
 and  provides some solids handling capacity.  Gases low in silicon tetra-
 fluoride  can be introduced directly to the packed section.
     The  spray section accounts for approximately 40 to 50 percent
 of the total length of the scrubber.  It consists of a series of
 countercurrent spray manifolds with each pair of soray manifolds followed
 by a system of irrigated baffles.  The irrioated baffles remove pre-
 cipitated silica and prevent the formation of scale in the spray chamber.
     Packed beds of both cocurrent and crossflow design have been
 tried with the crossflow design proving to be the more dependable.
The crossflow design operates  with the gas stream moving horizontally
 through the bed while the scrubbing liguid flows vertically through
 the packing.  Solids  tend to deposit near the front of the bed where
they can be washed  off by a cleaning spray.   This design also allows  the
                          6-3

-------
 use  of  a  higher irrigation  rate  at  the  front of the bed to aid in
 solids  removal.   The back portion of  the  bed is usually operated dry
 to provide  mist elimination.
     The  bed  is  seldom more than 3  or 4 feet in length, but this can
 be increased  if necessary with little change in capital or operating cost.1
 Several types of ceramic and  polyethylene packing are in use with
 Tellerettes probably the most common.   Pressure loss through the scrubber
 ranges  from 1 to 8  inches of  water  with 4 to 6 being average.1'3
     Recycled pond  water is normally  used as the scrubbing liquid
 in both the spray and packed  sections.  Filters are located in the
 water lines ahead of the spray nozzles  to prevent plugging by suspended
 solids.   The ratio  of scrubbing  liquid  to gas ranges from 0.02 to 0.07
 gpm/acfm  depending  upon the fluoride  content - especially the silicon
 tetrafluoride content - of  the gas  stream.3*4  Aporoximately one-third
 of this water is used in the  spray.section while the remaining two-thirds
 is used in the packing.
     The  packed  bed  is  designed  for a scrubbing liquid inlet pressure
 of about  4 or 5  pounds-per-square-inch  (qauge).  Water at this pressure
 is available from the pond  water recycle  system.  The spray section
 requires  an inlet pressure  of 20 to 30  pounds-per-square inch (qauqe).
This normally necessitates  the use  of a booster pump.  Spent scrubbina
water is  collected  in a  sump  at  the bottom of the scrubber and pumped
 to the gypsum pond.
                            6-4

-------
6.1.2  Emission Reduction
     The use of gypsum pond water as the scrubbing solution com-
plicates the task of fluoride removal regardless of the scrubber
design.  Gypsum pond water can be expected to contain from 0.2 to 1.5
percent fluosilicic acid  (2000-12,500 pom F) or most often, 5000-
6000 ppm F.  Decomposition of fluosilicic acid to silicon tetrafluoride
and hydrogen fluoride results in the formation of a vapor-liquid
equilibrium that establishes a lower limit for the fluoride concentra-
tion of the gas stream leaving the scrubber.  This limit will vary
with the temperature, pressure, and fluosilicic acid concentration of
the water.  Table 6-1 presents equilibrium concentrations (y1) calcu-
lated  from experimentally obtained vapor pressure data at three
temperatures and several fluosilicic acid concentrations.
Table 6-1.  CALCULATED EQUILIBRIUM CONCENTRATIONS OF FLUORINE IN
            THE VAPOR PHASE OVER AQUEOUS SOLUTIONS OF FLUOSILICIC
                                   ACID6
Fluosilicic acid
content of solution (wt %)

0.1C5
0.550
1.000
2.610
2.640
5.050
7.470
9.550
11.715
14.480
Total fluorine concentration
in vapor phase (ppm F)
50°C
2.4
3.8
4.4

5.6
8.2a
12. 4a
13.5
19.1
-
60°C
3.8
4.43
7.1
9.8a
_
14.2?
19. 4a
25.6
34.6
83.5
70°C
_
10. 5a
15.4
•20. 7a
_
54. la
208.5
-
—
—
 Average based on several  vapor pressure measurements
                         6-5

-------
     Providing that the solids loadinq of the effluent stream has
been reduced sufficiently to prevent plugging, the fluoride removal
efficiency of the spray-crossflow packed bed scrubber is limited
only by the amount of packing used and the scrubbing liquid.  Efficiencies
as high as 98.5 and 99.9 percent have been measured for scrubbers
installed at separate wet-process acid plants.1'7  Table 6-2 lists the
levels of fluoride control reached  by several wet acid plants tested
by the Environmental Protection Agency during the development of
SPHSS.  All plants used a sprav-packed bed type scrubber to control
the combined emissions from  the reactor, the filter, and several
miscellaneous sources and were felt to represent the best controlled
segment of the industry.  Gypsum pond water was used as the scrubbing
liquid.  Emission rates ranged from 0.002 to 0.015 nounds fluoride
(as F) per ton P20g input to the process.

Table 6-2.  SCRUBBER PERFORMANCE IN WET-PROCESS PHOSPHORIC ACID
                               PLANTS8
Plant
A
B
C
D
Scrubber design
spray-cocurrent packed bed
spray-crossflow packed bed
spray-crossflow packed bed
spray-crossflow packed bed
Fluoride emissions3
(Ib F/ton P205)
0.015
0.006
0.002, 0.012b
0.011
 aAverage of testing results
  Second series of tests
                            6-6

-------
      Spray-packed bed type scrubbers have seen only limited service in
 diammonium  phosphate and granular triple sunerohosphate plants and none
 at all  in run-of-pile triple superphosphate plants.  Table 6-3 oressnts
performance data, collected during the development of SPNSS, for
spray-crossflow packed bed scrubbers treating effluent streams from
dianmonium phosphate, granular triple superphosphate production, and
granular triple superphosphate storage facilities.  In mqst.cases, a
preliminary scrubber (venturi or cyclonic) was used to reduce the
loading of other pollutants (ammonia or solids) nrior to treatment in
the spray-crossflow packed bed scrubber.  Gyosum nond water was used as
the scrubbing solution except where indicated.  Fluoride emission rates
from dianmonium phosphate plants ranged from 0.029 to 0.039 nounds ner
ton PgOg input, while emissions from granular triple superphosphate pro-
duction facilities ranged from 0.06 to 0.18 pounds per ton PpOc-  Cranular
triple superphosphate storage facility emissions were measured at 0.00036
pounds per hour per ton of P^O,. in storage.
 6.1.3  Retrofit Costs for Spray-Crossflow Packed Bed Scrubbers
     This section discusses the costs associated with retrofitting spray-
 crossflow packed bed scrubbers in wet-process phosohoric acid, suoer-
 phosphoric  acid, diammonium phosphate, run-of-pile triple superphosphate,
and granular triple superphosphate plants.  Two separate approaches -
 retrofit models and retrofit cases  • are used to present cost information.
 Tne retrofit model approach is meant to estimate costs for an average or
 typical installation.  No specific plant  is expected to conform exactly
 to the description presented in these models.  Where possible, the retrofit
model treatment is supplemented by retrofit cases  - descriptions of specific
 plants which have added spray-crossflow packed bed scrubbers  to uonrade
 their original control systems.
                                6-7

-------
                        Table 6-3.  SPRAY-CROSSFLOW PACKED BED SCRUBBER PERFORMANCE
                                      IN DIAMMONIUM PHOSPHATE AND GRANULAR TRIPLE
                                              SUPERPHOSPHATE PLANTS9
 Type of
 facility
Sources controlled
Primary controls
Secondary controls
Fluoride emissions'
(Ib F/ton P205)
 DAP
 UAP
GTSP
GTSP
jGTSP
(storage
reactor, granulator,
drier, and cooler
reactor, granulator,
drier, and cooler
reactor, qranulator,
drier, and cooler
reactor, granulator,
drier, and cooler
storage building
3 venturi scrubbers
in parallel"
3 venturi scrubbers
in parallel6
3 venturi scrubbers
in parallel
process qases com-
bined and sent to 2
venturi  scrubbers in
parallel followed by
a cyclonic scrubber
3 spray-crossflow
packed bed scrubbers
in parallel

3 spray-crossflow
packed bed scrubbers
in parallel

3 spray-crossflow
packed bed scrubbers
in parallel

spray-crossflow
oacked bed scrubber
                        spray-crossflow
                        packed bed scrubber
   0.034, 0.029°
       0.039
   0.18, 0.06C
       0.21
                                O.OQ036n
 Average of testing results.

 Weak phosphoric acid scrubbinq solution.

cSecond series of tests.
.4
 Emission rate is in tenns of pounds T per hour per ton of P205 in storaqc.

-------
6.1.3.1   Retrofit Models
General  Procedure
     Each retrofit model provides the following information:
     1.   A brief description of the process in use,
     2.   A description of existing fluoride controls  and  the  sources
         treated,
     3.   A description of the retrofit project (including the reduction
         in fluoride emissions achieved), and
     4.   A breakdown of estimated retrofit costs.
Items 1  and 2 are self-explanatory, however, items 3  and  4 will  require
some discussion.  In the case of item 3, all retrofit systems are designed
to meet SPNSS emission levels.  A scaled plot plan of a model phosphate
fertilizer complex was used to estimate piping, ductwork, pumps, and fan
requirements.
     The procedure used for development of costs is a module approach,
starting with the purchase cost of an item - such as a pump, scrubber,
fan, e£c. - and building up to a field installed cost by using an
appropriate factor to account for ancillary materials and labor.    For
example, a pump of mild steel construction costing $10,000 is projected
to $17,600 field  installed.  The installation  cost index in  this case
is 1.76 and the  installation cost is $7,600.   If the pump were built
of stainless steel, the purchase cost would  be $19,300 but the installa-
tion cost would  remain  at  $7,600 since  it  is  calculated  for  the element
of base construction  - mild  steel.
                               6-9

-------
     The purchase cost of the various items on an equipment specifica-
tion list drawn up for each model plant were derived from  literature,
manufacturer's bulletins, telephone quotations from suppliers, and
a report prepared by the Industrial Gas Cleaning Institute.    Scrubber
costs were obtained by combining designer, manufacturer  and user estimates.
Purchase costs were scaled up to field installed costs by  using an
appropriate installed cost index.  Table 6-4 is a list of  the cost  indices
assumed for this analysis.
                    Table 6-4.  INSTALLED COST INDICES

      Item                              Installed cost index

Pumps                                          1.76
Piping (except valves)                         2.00
Scrubbers                                      1.20
Centrifugal fans                               1.60
Stack                                          1.50
Ductwork                                       1.40

     The sum of the field installed equipment cost is the  direct
cost billed to a particular project.  Other costs such as  general
engineering, procurement of goods and services, equipmental  rentals,
field supervision, labor burdens, contractor fees, freights,  insurance,
sales taxes, and interest on funds used in construction are included
in the catch-all category of indirect costs.  In this study,  the  indirect
cost is assumed to be 35 percent of the direct cost.  In addition,  a

                             6-10

-------
contingency factor is included in a capital project to account for
unforeseen expenditures.  Due to the nature of the type retrofit
projects studied in this document, a factor of 25 percent of direct
costs has been incorporated in the capital estimates.   The total
capital requirement of a project therefore is equal to the sum of
the direct cost, the indirect cost, and the contingency cost, as
indicated in equation 6-1:
     I = D+0.35D+0.25D
     where I = total  capital
           D = total  direct cost
     The following assumptions were used in the development of cost
estimates:
     1.  The purchase costs of scrubbers were determined from the most
         recent manufacturer quotations, users wherever possible,
         and the Industrial Gas Cleaning Institute.  The purchase
         cost of ductwork, stacks, and centrifugal fans were derived
                                                     12
         from a manufacturer's published list prices.     The costs
         are 1974 estimates based, for the most part, on the use of
         corrosion resistent fiber reinforced plastics (FRP) as the
         material of construction.
     2.  Installed costs for scrubbers, ductwork, stacks, and centri-
         fugal fans (including drivers) were derived by multiplying
         the purchase costs by the appropriate cost index from
         Table 6-4.  An inherent assumption is that FRP is a base
                              6-11

-------
    construction material suitable for application of the
    listed indices.
3.  Demolition costs were estimated from contractor Quotations  to  be
    $2500/8-hour day.
4.  Piping costs were derived for a corrosion resistant material
    called Permastrand.
5.  Pumps were assumed to be of stainless steel construction.
    Cost estimates were obtained from the literature.    These
    costs» originally published in 1968, were increaser 28 oercent
    (5% per year) to update to 1974 costs.
6.  Costs for pump motors were obtained from the literature and
    adjusted for inflotion usirg the same procedure described for
    pumps.
7.  Special compensatory factors for construction costs were
    incorporated into the ROP-TSP and GTSP storage facilities.
    Such factors appear under the headings of "sealing of storage
    building", "curing belt hooding", and "structural steel suonorts/
    bldg."  The costs for these items v/ere pro-rated on the basis
    of a recent engineering project study for a fertilizer producer.
8.  Cost for performance tests were based on a telephone survey of
    independent contractors.
                        6-12

-------
9.  Annualized Costs
    a.   Capital charges are 16.3 percent of  the  total capital
        outlay.  This was derived from the capital  recovery
        factor equation,
                i (1  + i)n
            R =	  P                          (6-2)
                (l+i)n-l
                where:  P = capital  outlay (principal),
                        R = periodic capital  charge,
                        i = annual  interest  rate (10$),  and
                        n = number of payments  (10)
    b.   Maintenance and repair charge were assumed  to be 3
        percent of the original  investment.
    c.   Taxes, insurance, and administrative costs  were  assumed
        to  be 4 percent of the original  investment.
    d.   Operating labor costs were estimated at  $2,000 per
        year for the simple operation (phosphoric acid plant
        and GTS storage) $4000 for the more  difficult operations
        (DAP, ROP, and GTSP processing).15
    e.   Utilities (electricity only) were based  on  a rate of
        $0.015 per kw-hr and 7,900 hours operation  per year.
                          6-13

-------
Wet Process Phosphoric Acid Plant
    The model plant uses the Prayon process for the manufacture of
wet process phosphoric acid.  Figure 6-2 presents a basic flow dia-
gram of the operation.  The reactor is a multicompartment unit (9
compartments) with a designed production rate of 500 tons per day
PoOc-  Temperature control for the reactor is provided by a vacuum
flash cooler.  Under normal conditions, the reactor is maintained
at a temperature of 160-180°F and produces an acid containing 30
percent P2°5-
     Filtering and washing of the by-product gypsum is accomplished
with a Bird-Prayon tilting pan filter.  The separated gypsum is re-
moved from the filter, slurried with water, and pumped to a settling
pond.  Product acid from the reactor (30% P00C) is stored before
                                           Z b
being sent to the concentration system.  Three vacuum evaporators in
series are used to concentrate the acid to 54 percent PO^C-  Evaporator
off gases are treated in barometric condensers for removal of conrten-
sables; a large percentage of the fluorides are also collected.
    Retrofit costs for some wet-process phosphoric acid plants
could be substantially greater than those estimated for this plant.
The retrofit model is of moderate complexity and includes all of the
activities with which most installations are expected to become
involved; however, increases in the gas volume being treated, additions
to the scope 6f work, and space limitations are all factors capable
of inflating the project cost above that estimated.  Modifications
to the plant drainage system and installation of a ventilation system
                             6-14

-------
STEAU
               CONDENSER
               ~\ •• '~I

                  "-
                                                                   TO A3 PCLU
        i  P.'  A  ^1 /a:
                                   ^'^FiE'tjL  P ••••"'J':
                                     ,.  ,....,..-. j...~: |


                                    "•* LQ Hi  Hi 111    T;ic io-rc^-iu
                                                        ' _: ,       p.i-->; ' '':--"' '•
                                               ,  . . .          •;•-'!!•••• ^
                I
           DIGESTED
«'i vrp
J j i v u C.
ScrlTANXS
                                                                  ..
                                                                 • i..  .H ••.•"./
          FIGURE 6-2.  MANUFACTURE OF MIT-PROCESS PhOS^iiORIC ACID.

-------
for the filter are two items which have not been included within
the scope of the model but which could be encountered by some plants.
    Costs will be estimated for two effluent stream sizes - 25,000
and 35,000 scfm.  The effluent stream from an actual 500 ton per day
plant could range from about 20,000 to 40,000 scfm dependino primarily
on the digester design.
Existing Controls (Case A)
    Existing controls consist of a cyclonic spray tower used to treat
the digester and the filter ventilation streams.  Gypsum pond water
is used as the scrubbing liquid.  This scrubber has been in operation
for eight years.  Figure 6-3 shows the location of the unit.
    Volumetric flow rates and fluoride concentrations associated
with the various emission sources are listed in Table 6-5.  The flow
rates are based on a combination of literature data, source test
information, and control equipment design data.  Fluoride removal
efficiency of the cyclonic spray tower is 81 percent.  Total emissions
to the atmosphere from the sources listed in Table 6-5 are 7.3 pounds
of fluoride per hour with existing controls.  Several miscellaneous
sources of fluoride such as the flash cooler seal tank, the evaporator
hotwell, the filtrate sump, the filtrate seal tank, and the filter
acid storage tanks are uncontrolled.  Emission rates from these
sources are unknown.
                          6-16

-------
                          DIGESTER AND FILTER
                          VENT GASES
                                                 CVCLONIC SPRAY TOMER
                                    ooo
    PHOSPHORIC (~^)  (~*)
    ACID STORAGE^-'  ^^
                        EVAPORATORS
en
               o  o
                           FILTER    _
                           ACID STORAGE
WPPA
PLANT
                                           125'
T
100'

_L
                                                      ROCK mrj
                                                      FROM GRIPPING MILL
                    Figure 6-3.  fXISTINR CONTROL  EQUIPMENT LAYOUT FOD "ODEL  1,'PPA  PLANT.

-------
       fi_5.  . FLOW RATES AND FLUORIt.-E CONCENTRATIONS OF VJPPA PLANT
              EFFLUENT STREAMS SZNT TC EXISTING  CCNTR?LS  (CASE  -)
Emission source
Digester vent gas
Filter vent gas
Flow rate
(SCF'-i)
10,000
7,500
Fluoride concentration
(mg/SCF) (ppm)
25
5.5
1050
23*
 Retrofit Controls (Case A)
     The retrofit consists of the reolacement of the cyclonic  spray
 tower with a crosstlow packed bed scrubber.   Limitations  imposed
 by the arrangement of existing equipment require the new  scrubber
 to be installed at a site 50 feet from the one previously occupied
 by the tower.  Gypsum pond water will be used as the scrubbing liquid.
 Several miscellaneous sources (flash cooler seal tank, evaporator
 hot well,^filtrate sump, filtrate seal tank, and acid storage tanks)
will  be  vented  to  the  new unit which  is  designed to meet SPNSS
requirements  for wet-process  phosphoric  acid  plants [0.02  pounds
fluoride  per  ton P20g  input). This  corresponds  to an emission  rate
of 0.42 pounds  fluoride  per hour.   Table 6-6  summarizes tbe volumetric
flow  rates and  the fluoride concentrations associated with the
emission  sources to be treated.
                           6-18

-------
 Table 6-5.   FLOU R.VTES  \'!D FL'JORIDE CONCENTRATIONS  OF WPPA  PLANT
                   T ST°EAMS SFWT Tn prTn°FITTF.P C™!TPnl^
Emission source
(Digester vent gas
Filter vent gas
.''iscellaneous
Flow rate,
(SCR1)
10,000
7,500
7, 500
Fluoride concentration
(ng/SCF) (pom)
25
5.5
0.3
105"
230
13
    Figure 6-4 provides a view of  the  plant  layout  folio-vino the com-
oletion of the retrofit oroject.   Installation of the new scrubber
requires the rearrangement of the  existing ductwork and the addition
of a new ventilation system to handle  the miscellaneous sources.  P
net1 fan vill be required for the digester-filter ventilation system
because of the hiqher pressure drop of the crossflow sacked bed scrub-
ber.  Treated gases will be exhausted  from a newly installed 75-foot
tall stack.

    Scrubbing water will be obtained from existing plant water lines.
A booster pump is required to provide  40 psig water for the spray
section.  Pond water is assumed to have the properties shown in
Table 6-7.   All scrubbing water will be recycled to the gyosum pond in
the existing plant drainage system.
                           6-19

-------
               FILTER, FILTRATE fir.P AND
               FILTPATE SEAL TANK
EVAPORATOR HOTHEL
:|f    \     SPPAY-CPP?
  ^^.   ^     ' .    CTflC


PHOSPHORIC V^y
^ ACID _
• STORAGE ( ^\
5 \J
EVAPORATORS

O
o.

ooo
!



. riu
Q WPPA
/C
FILTER
J PLANT


ACID i. 	 . 1051
STORAGE 1

— i



             PACKED PEP


1-pIGFSTF.P AMP FILTER
                                    PPCK COMVEVER
                                    FRO'* GPINDINR MILL
FIGURE 6-4.  PETROFIT  CONTROL EQUIPMENT LAYOUT FOR MnpEL WPP/» PLAf''T.

-------
                  Table 6-7.   POND  WATER  SPECIFICATIONS
                                                      15

Pond Hater pH
Temp., °F
Sn wt %
O *j it 3 *• w /O
tt
P2o5, \/t %
H2SiF6, wt %
Fluoride, wt %
Design
2.0
80.0
0.15
0.1
0.63
0.5
fin.
1.2
55
-
-
0.25
0.2
Max.
2.2
88
-
-
1.0
0.8
    Major retrofit items are listed in Table 6-8.   All  ducting,  piping,
and motors are specified in terms  of the nearest  aporooriate  standard
size.  Table 6-? oresents typical  ooerating conditions  for  the new
scrubber and the estimated number  of transfer units (NTH) necessary
to meet emission requirements.   The NTU were calculated
by using equation 6-3.
               NTU required  =  In
                                   y2
(6-3)
         where:   y2 = fluoride concentration o* gas  stream  at  the
                      scrubber inlet
                 y, = fluoride concentration of gas  stream  at  the
                      scrubber outlet
                 y' = fluoride concentration cf gas  stream  in
                      equilibrium with entering liquid stream
Table 6-10 lists the estimated capital and annualized costs of the
project.
                             6-21

-------
      Table 6-8.  MAJOR RETROFIT ITEMS FOR MODEL WPPA PLANT (CASE A)
1.  Ductwork required to connect existing diqester-fliter ventilation
    system with retrofit scrubber - 50 feet of 36-inch duct.   New
    ventilation system connecting miscellaneous sources with  control
    system.  Requirements are - 175 feet of 9-inch duct, 50 feet  of
    10-inch duct, 125 feet of 12-inch duct, 75 feet of 16-inch duct,
    100 feet of 20-inch duct, and 50 feet of 24-inch duct.

2.  Pipe connecting spray-crossflow packed bed scrubber with  existing
    plant water "line - 150 feet of 6-inch pipe.

3.  Booster pump for spray section - 190 gpm, 81 feet total dynamic
    head  (TDH), 7.5 horsepower motor.

4.  Centrifugal fan for digester - filter ventilation system  -
    17,500 scfm, 620 feet TDH, 50 horsepower motor.  Fan for  miscel-
    laneous sources - 7,500 scfm, 660 feet TDH, 20 horseocwer motor.
5.  Removal of cyclonic spray tover *nd existing stack.

6.  Spray-crossflow packed bed scrubber.  Unit will be reouired to
    reduce the fluoride concentration to C.13 nc/SCF (5.6 pom)
    when using the pond water specified in Table 6-7 and treatina
    the gases listed in Table 6-6.

7.  Stack - 75-foot tall, 4-foot diameter.
                           6-22

-------
   Table 6-9.   OPERATING  CONDITIONS  FOR SPPAY-CROSSFLra I PACKED
                  EFD SC'^.BFP F-^P "fDEL 'PP/1  PLANT, CASE A
                             9 tons/da" P°)
Gas to Scrubber
    Flow, SCFI1                  25,000
    Flow, DSCFM                 22,725
    Flow, ACFM                  27,150
    Temp., °F                   116
    Moisture, Vol . %            9-1
    Fluoride  (as  F), Ib/hr      38.7
    Fluoride  (as  F), ppm        492

 Gas from Scrubber
     Flow, SCFM                  24,400
     Flow, DSCFM                 22,725
     Flow, ACFI1                  25,700
     Temp., °F                   100
     Moisture, Vol . %            6.5
     Fluoride  (as F), Ib/hr      0.42
     Fluoride  (as F), ppm        5.6
     Fluoride  Removal, wt %      99
      Estimated y',  ppm  (see      0.85
      page 6-5)
      Estimated NTU required       4.7
                               6-23

-------
        Table 6-10.  RETROFIT COSTS FOR MODEL WPPA PLANT, CASE A
                           (500 tons/day PgOg) November 1974


                                                                  Cost ($)

A.  Direct Items (installed)

    1.  Spray-crossflow packed bed scrubber                        58,900
    2.  Ductwork                                                   18,600
    3.  Piping                                                      2,400
    4.  Pumps and motor                                             3,400
    5.  Centrifugal fan and motor                                  14,300
    6.  Removal of old equipment                                   12,500
    7.  Stack                                                      15,800
    8.  Performance test                                            4,000

    Total Direct Items                                            129,900

B.  Indirect Items

    Engineering construction expense, fee,interest on
    loans during construction, sales tax, freight insurance.
    (35% of A)                                                     45,500

C.  Contingency
    (25% of A)                                                     32,500

D.  Total Capital Investment                                      207,900

E.  Annualized Costs

    1.  Capital charges                                            33,900
    2.  Maintenance                                                 6,200
    3.  Operating labor                                             2,000
    4.  Utilities                                                   6,900
    5.  Taxes, insurance, administrative                            8,300

    Total Annualized Costs                                         57,300
                                    6-24

-------
Existing Controls (Case B)
    The existing control system is the same as described in case A;
a cyclonic spray tov;er is used to treat the digester and filter
ventilation streams.  Fluoride collection efficiency of the tower is
81 percent,  f'inor miscellaneous sources of fluoride are uncontrolled.
    Volumetric flow rates and fluoride concentrations of the various
effluent streams being controlled are listed in Table 6-11.  Emissions
from the sources listed are currently 11.0 oounds of fluoride per
hour.
Table 6-11.  FLOW RATES AND FLUORIDE CONCENTRATIONS OF WPPA PLANT
               EFFLUENT  STREAMS SENT TO EXISTING CONTROLS  (CASE  B)
Emission Source
Digester vent gas
Filter vent gas
i
Flow Rate
(SCFM)
20,000
7,500
Fluoride Concentration
(mg/SCF) (pom)
20 840
5.5 230
Retrofit Controls (Case B)
    Details of the retrofit oroject remain the same as in the initial
case.  The cyclonic spray tower treating the digester-filter gases
will be replaced with a spray crossflow packed bed scrubber de-
signed to handle the sources listed in Table 6-12.
                          6-25

-------
 Table 6-12.   FLOW RATES flfJn FIJinoiPE CONCENTRATIONS  OF UP PA PLAMT
              EFFLUENT STRESS SI.'iT T? PIIT^FITTE"  rnMTD«LS (rfiSE a)
JEmission Source
Digester vent gas
Filter vent gas
'iscellaneous

Flow pate , Fluoride Concentration •
(SCF") . (mcj/SCF) (n0irj)
i
| 20,000 20
7,500 5.5
i 7,500 ; 0.3
1
1
P-40
?30
13
•
    £ list of major retrofit items is presented in Table 6-13 while
operating conditions for the new scrubber are provided in Table 6-14.
Estimated capital and annual i zed costs of the orrqram is listed in
Table 6-15.  Increasing the capacity of the system by intnn^ SCF*'
has resulted in a 20 percent increase in the capital cost of the
program and a 21 percent increase in the annualized cost.

    Table 6-13.  MAJOR RETROFIT ITEMS FOR MODEL WPPA PLANT (utoE C)
1.  Ductwork required  to  connect existing dipester-filter ventilation
    system v/ith  retrofit  scrubber  -  50 feet of "R-inch duct,  few
    ventilation  system connect! no  miscellaneous sources with control
    system - 175 feet  of  9-inch duct, 50 feet of 10-inch duct, 125
    feet of 12-inch duct,  75  feet  of 16-inch duct, 100 *eet of 2^-
    inch duct, and 50  feet of 2^-inch duct.

?.  Pioe connecting spray-crossflow  packed bed scrubber yit> existing
    plant water  line -  150 feet of 8-inch oine.

3.  Dooster pump for spray section - 269 apn , 81 feet total dynamic
    head (TOH),  10 horsepower motor.

                         6-26

-------
ft.  Centrifugal fan ^or dioester - filter ventilation system -

    27,500 scfm, 604 feet TPM, 75 horsepower motor.  Fan fr*r

    miscellaneous sources - 7,500 scfm, 660 feet TDK, 20 horsenover

    motor.


5.  Removal of cyclonic soray  tower and existing stack.


6.  Soray-crossflow packed bed scrubber.  Unit will be required

    to reduce the fluoride concentration to 0.09 mg/scf (3.9 ppm)

    when using the pond water specified in Table 6-7 and treating

    the gases listed in Teble 5-11.


7.  Stack - 75 foot tall, 5 foot diameter.
Table 5-14.  CPERflTING CONDITION'S FOR SPRAY-CROSSFLOW PACKED BF.D
                  SCRUBBER FOR I10DEL WPPA PLANT, CASE B
                           (500 tons/day Pg^)

Gas to Scrubber
    Flow, SCFM                  35,000
    Flow, DSCFH                 31,800
    Flow, ACFfl                  37,600
    Temp., °F                   109
    Moisture, vol. %            9.1
    Fluoride (as F) , Ib/hr      58.1
    Fluoride (as F), ppm        529

Gas from Scrubber
    Flow, SCFM                  34,000
    Flov, DSCFf                 31,800
    Flow, ACFK                  35,600
    Temo. , °F                   95
    I'oisture, vol . %            6.5
    Fluoride, Ib/hr             0.42
    Fluoride, ppm               3.9
    Fluoride removal, wt %      99.3
    Estimated y1 , pom           0.85
    Estimated NTU required      5.2
                       6-27

-------
      Table 6-15.  RETROFIT COSTS FOR MODEL WPPA PLANT,  CASE B
                      (500 tons/day P2C5)  November  1974
A.  Direct Items  (installed)

    1.  Spray-crosslow packed bed scrubber
    2.  Ductwork
    3.  Piping
    4.  Pump and motor
    5.  Centrifugal fans and motors
    6.  Removal of old equipment
    7.  Stack
    8.  Performance test

    Total Direct  Items

B.  Indirect Items

    Engineering construction expense* fee, interest on
    loans during  construction, sales tax, freight insurance.
    (35% of A)

C.  Contingency
    (25% of A)

D.  Total Capital Investment

E.  Annualized Costs

    1.  Capital charges
    2.  Maintenance
    3.  Operating labor
    4.  Utilities
    5.  Taxes, insurance, administrative

    Total Annualized Costs
                                                                Cost ($)
 78,800
 20,000
  3,300
  5,300
 16,000
 12,500
 15,800
  4,000

155,700
 54,500


 38,900

249,100
 40,600
  7,500
  2,000
  9,300
 10,000

 69,400
                                  6-28

-------
Superphosphoric Acid
     Two processes are currently available for the manufacture of
superphosphoric acid - vacuum evaporation and submerged combustion.
All but two of the existing U.S. production facilities use the vacuum
evaporation process and it is belteved that new facilities will
favor vacuum evaporation.  No retrofit model will be presented for vacuum
evaporation plants because the low level of fluori.de emissions from
these facilities do not require control equipment in order to meet the
emission guidelines.
     Existing submerged combustion plants are expected to continue
operation with some expansion in capacity possible.  Retrofitted control
equipment may be needed to meet the emission guidelines for this type
of process.  A  retrofit model is presented for a plant using the
submerged combustion process in order to estimate the costs of applying
control equipment.  The costs are developed based upon control equip-
ment designed to meet the fluoride emission guideline of 0.01 pounds per
ton of P205 input.

     The model plant uses the Occidental Agricultural Chemicals process
for the production of superphosphoric acid.  Desianed production capacity
is 300 tons per day P,,05.  Figure 4-6 is a basic flow diagram of the
process.
     Wet-process acid containing 54 percent P?05 is fed to the
evaporator and concentrated product acid containinq 72 percent tf
is withdrawn.   The acid is maintained at its boiling point bv intro-
ducing a stream of hot combustion pases  into the acid Dool.   Gaseous
                            6-29

-------
 effluent from the evaporator is cooTed by direct contact with weak
 phosphoric  acid  feed  in  the evaporator vapor outlet duct, treated for
 phosphoric  acid  recovery,  given additional cooling, and treated for fluoride
 rejnoval.
 Existing Controls
      Exhaust gases  from  the evaporator are treated for the recovery
 of entrained acid before being sent  to fluoride controls.  The phosphoric
 acid recovery system  consists of  an  initial cyclonic separator followed
 by a baffled spray  duct  and a second cyclonic separator.  Weak phosphoric
 acid (30% P20g)  i?  used  as the scrubbing liquid in the soray duct.
      Fluoride controls consist of 3  spray chambers in series followed
 by an impingement scrubber.  The  spray chambers are baffled and each
 is followed by an entrainment separator.  Pond water is used as the
 scrubbing liquid in all  cases.  Emissions to the atmosphere are 1.56
 pounds of fluoride  per hour with  existing controls.16
Retrofit Controls
     The retrofit cost projection  is  based on reolaceraent of the
impingement  scrubber with a spray-crossflow packed bed scrubber*  Since
available space is usually  limited, the new unit is assumed to be
installed at the  site  previously occupied by the impingement scrubber.
Figure 5-6 provides  a  schematic diagram of the plant following
completion of the retrofit  project.
     Gypsum  pond water will be used as the scrubbing liquid.  Pond water
characteristics are  listed  in Table 6-7.  Retrofitted controls are
designed to  reduce fluoride emissions to C.12 pounds fluoride oer hour.
                              6-30

-------
SPRAY-CROSSFLOW
PACKED BED    _
SCRUBBERS     t
            100
                                                    STACK
cr>

CO
                                           I
                                                    SPA
                                                   PLANT
                                                   TOO1
OACID FEED
XTANKS
                                                          PRODUCT HOLD
                                                          ING TANK
       SPRAY-CROSSFLOW PACKED BED
       SCRUBBER
                                     Figure 6-5.  RETROFIT CONTROL EQUIPMENT LAYOUT ^OR MODEL SPA PLANT

-------
     Installation of the spray-crossflow packed bed scrubber will
require moderate alteration of existing ductwork and construction  of  a
new pipe line connecting the scrubber to the existing water supply.   No
       4
additional fans will be required.  Treated oases will be exhausted from
the existing stack.  Scrubbing water is to be recvcled to the ovosuro  pond
in the existing drainage system.
     A list of major items  required for the  retrofit oroject is
presented  in Table  C-16.  Table  6-17 provides   operating conditions for
the new  scrubber.   Retrofit cost estimates are  listed in Table  6-18.

           Table  6-16.  MAJOR RETROFIT  ITEMS  FOR MODEL SPA  PLANT

 1.    Ductwork -  modification of existinc  ducting to connect new sorav-
      crossflow packed bed scrubber.   Requirements are 100  feet of 30-inch
      duct.
 2.    Line connecting scrubber to main pond water supply system -  150
      feet of 4-inch pipe.
 3.   Centrifugal pump - 130 gpm,113 feet total dynamic head  (TDM), 7.5
      horsepower motor.

 4.   Removal of  impingement scrubber.

 5.    Supports and  foundations.
 6.    Spray-crossflow packed bed scrubber.   Unit is required  to reduce
       the fluoride concentration to 0.09  mg/SCF (4 npm) when  usinq pond
       water specified in Table 6-7 and treating aas stream described in
       Table 6-12.
                                    6-32

-------
Table 6-17.  OPERATING CONDITIONS FOR SPRAY-CROSSFLOW  PACKED
                 BED SCRUBBER FOR MODEL SPA PLANT
                      (300 Tons/Day P20g)

Gas to Scrubber
     Flow, SCFM                               9,800
     Flow, DSCFM                              9,110
     Flow, ACFM                              10,600
     Temp., °F                                  115
     Moisture, vol.  *                           7.0
     Fluoride (as F), Ib/hr                     3.9
     Fluoride (as F), ppm                       126
Gas from Scrubber
     Flow, SCFM                               9,400
     Flow, DSCFM                              9,110
     Flow, ACFM                               9,760
     Temp., °F                                  90
     Moisture, vol.  %                           3.0
     Fluoride (as F), Ib/hr                    0.12
     Fluoride (as F), ppm                       4.0
     Fluoride removal, wt %                   96.7
     Estimated y1, ppn                         0.85
     Estimated NTU required                     3.7
                             6-33

-------
            Table 6-18.  RETROFIT COSTS FOR MODEL SPA  PLANT
                          (300 tons/day P205)  November 1974


                                                                 Cost ($)

A.  Direct Items (installed)

    1.  Spray-crossflow packed bed scrubber                       37,600
    2.  Ductwork                                                   5,000
    3.  Piping                                                     1,900
    4.  Pump and motor                                             3,400
    5.  Removal of old equipment                                  12,500
    6.  Performance test                                           4,000

    Total Direct Items                                            64,300

B.  Indirect Items

    Engineering construction expense, fee, interest on
    loans during construction, sales tax, freight insurance.
    (35% of A)                                                    22,500

C.  Contingency
    (25% of A)                                                    16,000

D.  Total Capital Investment                                     102,800

E.  Annualized Costs
    1.  Capital charges                                           16,800
    2.  Maintenance                                                3,000
    3.. Operating labor                                            2,000
    4.  Utilities                                                    700
    5.  Taxes, jnsurance, administrative                           4,000

    Total Annualized Costs                                        26,500
                                   6-34

-------
 Pi ammonium Phosphate
      This plant uses the TVA process for the production  of diammoniuro
 phosohate.  A flov diagram of the operation is  provided  in Figure 4-9.
 The  model  plant has a designed production capacity  of approximately
 1080 tons  per day diammonium phosphate  (500 T/D P205).
      A preneutralization reactor  is  used for the initial  contacting
 of the anhydrous ammonia and the  phosphoric acid.   Completion  of
 the  reaction and solidification of the  product  occurs  in  the granula-
 tor.   Effluent gases from the preneutralization reactor  and the  granu-
 lator are  treated for ammonia recovery  and  fluoride control before
 being vented to the atmosphere.
      A gas-fired rotary  drier is  used to remove excess moisture  from
 the  product.   Drier flue gases are vented through dry  cyclones for
 product recovery before  being treated for ammonia removal.  Air
 streams vented from accessory cooling and screening equipment  are
 treated for  particulate  removal before  being  exhausted.
 Existing Controls
      Exhaust gases  from  the  preneutralization reactor and  the granula-
 tor are combined  and  vented  to a  venturi  scrubber for ammonia  re-
 covery.  Weak  phosphoric  acid  (30% P205)  serves  as  the scrubbing
 liquid.  Approximately 95 percent  of the  anmonia is  recovered and
 recycled to  the  reactor.  Fluorides stripped  from the phosphoric
 acid  in the venturi  are  removed by a cyclonic spray  tower  using
 gypsum pond water as  tiie  aLr.nrbinq solution.  Fluoride removal
efficiency is  74 percent.
                             6-35

-------
     The drier flue gases are treated for product recovery before
being- sent to additional controls.  Collected particulate is re-
cycled to the granulator.  A venturi scrubber using weak phosohoric
acid is used for ammonia recovery.  Ammonia removal efficiency is
approximately 94 percent.  No additional scrubbing is practiced.
     Air streams vented from product cooling and screening equip-
ment are sent through  dry cyclones  for product recovery, combined,
and treated  in  a venturi scrubber for particulate  removal.  Weak
phosphoric acid serves as the  scrubbing  solution.  Collected DAP is
recycled  to the reactor.
     Volumetric flow rates  and fluoride  concentrations  associated with
the  three major emission sources are presented  in  Table 6-19.   The
values  listed are  estimates based on source test results and data  ob-
tained  from a recent contract study of control  equipment costs  (5).
Fluoride concentrations presented for the reactor-granulator and  the
drier  gas  streams  are values at the outlet of the ammonia recovery
scrubbers.   Total  fluoride emissions from the sources  identified  in
Table  6-19 are 4.95 pounds per hour with existing controls.
Table  6-19.  FLOW RATES AND FLUORIDE CONCENTRATIONS FOR DAP PLANT
                           EMISSION SOURCEST7.18
 Emission source            Flow  rate       Fluoride concentration
                             (SCFM)         (mg/SCF)         (ppm)
 Combined  reactor-granula-
 tor vent  gases               30,000           0.65             27
 iDrier  oases                  45,000           0.36             15
 Cooler and screening equip-
 ment vent gases	45.000	0.36_    	15_
                                  6-36

-------
 etrofit Controls
     The retrofit consiscs 'A the replacement o* the cyclonic spray
to-..er cr, the reactcr-c-anulator stream \-ith e soray-crossflcv. packed
bed scrubber and' the adclicion cf spray- crossflo1.. packed bad scrubbers
as tail gas units tc the drier and cooler streans.  Sypsur.i pond
v/atcr v;111 be used as the scrubbing liquid.  Pond water is available
at 80°F with the properties listed in Table 6-7.  Tha control system
 is  designed to  conform with the fluoride emission guideline of 0.06
pounds cr fluoride per  ton  P2?5  Input -  1.25 pounds fluoride per hour.
     Existing controls  are  located as depicted  in  Figure 6-6.  The
rrrangenent  of  equipment  is such that the  spray-crossflov/  packed bed
seniors can be  installed  adjacent to  the venturi  scrubbers  after
i-iodarata  alteration  of the  ductvork.  A new water line  must bs  in-
stalled  to  satisfy  the increased da*and caused  by the retrofitted  scrub-
 bers.   A  new fan  will  also  be required  for both the drier and the  cooler
 streaRi to compensate for the  pressure drop of the secondary scrubber.
 Treated gases will  be exhausted from the existing stack.   Spent scrub-
 bing water is to be recycled in the existing drainage system.
      Figure 6-7 provides a view of the plant layout after the instal-
 lation of new controls.  A list of major retrofit items is provided
 in Table 6-20.  Table 6-21 presents operating  conditions  for the  sprsy-
 crossflow packed bed scrubbers.  Total  capital  cost  and annual i zed
 cost estimates for  the project  are presented in Table  6-22.
                               fi-37

-------
     GYPSUM
     POND
CD
CO
03
               1200'
                                                    MISCELLANEOUS
                                            DRIER                 STACK
l> l>
DAP
PRODUCTION
r> n.


DAP
STORAGE

REACTOR - GRANULATOR
L 	 150'- vJ *— 300' 	 '• 	 *>
                                                                                                         125
    v  _  VENTURI SCRUBBER
    O  	  CYCLONIC SCRUBBER
FIGURE 6-6.  EXISTING CONTROL EQUIPMENT LAYOUT FOR MODEL DAP PLANT.

-------
GYPSUM
POND
             1200'
                                      DRIER
                                              MISCELLANEOUS
                                              ic—     a
DAP
PRODUCTION
                   STACK
DAP
STORAGE
                                              k-a-
                                            REACTOR - GRANULATOR
                                           -150'
1
                                                                                                 125'
                                                          1
                                  300'
  v_   VENTURI SCRUBBER
  o —   SPRAY CROSS-FLOW PACKED BEJ SCRUBBER
                                              FIGURE 6-7.   RETROFIT  CONTROL  EQUIPMENT  LAYOUT  FOR MODEL DAP PLANT,

-------
    Table 6-20.  MAJOR RETROFIT ITEMS FOR MODEL DAP PLANT
1.   Ductwork - removal of cyclonic spray tower from service  and
     connection of three spray-crossflow packed bed scrubbers.
     Requirements are 100 feet of 60-inch duct and 50 feet of 54-
     inch duct.
2.   Water line connecting gypsum pond with spray-crossflow packed
     bed scrubbers - 1200 feet of 16-inch pipe with a 200-foot  branch
     of 14-inch pipe and a 150-foot branch of 6-inch pipe.
3.   Two centrifugal pumps {one -spare)  -  2550  gpm,  105 feet
     total dynamic head (TDH), 125 horsepower motor.  Booster pump
     for.spray section of both-the drier  and the cooler stream scrubber
     345 gpm, 89 feet TDH, 7.5 horsepower motor.
4.   Two centrifugal fans - 45,000 scfm,  285 feet TDH, 50 horsepower
     motor.
5.   Removal of cyclonic spray tower.
6.   Supports and foundations.
7.   Three spray-crossflow packed bed scrubbers.  When using specified
     pond water and  treating  gases described  in Table 6-19, scrubbers
     are required to obtain performance indicated  in Table 6-21.

-------
Table 6-21.  OPERATING CONDITIONS FOR SPRAY-CROSSFLOW PACKED
                     BED SCRUBBERS FOR MODEL DAP PLANT
                            (500 Tons/Day P90c)

Gas to scrubber
Flow, SCFM
Flow, DSCFM
Flow, ACFM
Temp. , °F
Moisture, vol. %
Fluoride (as F), Ib/hr
Fluoride (as F), ppm
Gas from scrubber
Flow, SCFM
Flow, DSCFM
Flow,. ACFM
Temp., °F
Moisture, vol. %
Fluoride (as F), Ib/hr
Fluoride ('as F), ppm
Fluoride removal, wt %
Estimated y1 , ppm
Estimated NTU required
Reactor-
granulator
stream

30,000
18,000
34,000
140
40
2.58
27.1

19,400
18,000
23,600
100
7
0.44
5.9
83
1.05
1.69
Dryer
stream

45,000
29,200
52,700
160
35
2.14
15.0

31 ,500
29,200
38,400
100
7
0.36
3.0
83.5
1.25
2.06
Cooler
stream

45,000
43 ,600
49,600
125
3
2.14
15.0

45,400
43,600
48,000
100
4
0.45
3.0
79
1.05
1.94
                               6-41

-------
            Table 6-22.  RETROFIT COSTS FOR MODEL DAP PLANT
                         (500 tons/day P20g)  November 1974


                                                                  Costs  ($)

A.  Direct Items (Installed)

    1.  Spray-crossflow packed bed scrubbers (3)                  285,000
    2.  Ductwork                                                   16,700
    3.  Piping                                                     26,200
    4.  Pumps and motors                                           34,500
    5.  Centrifugal fans and motors                                33,000
    6.  Removal of old equipment                                   12,500
    7.  Performance test                                           4,000

    Total Direct Items                                            411,900

B.  Indirect Items

    Engineering construction expense, fee, interest on
    loans during construction, sales tax, freight insurance.
    (35X of A)                                                    144,200

C.  Contingency
    (25% of A)                                                    103,000

D.  Total '• Capi tal. Invetteent                                      659,100

E.  Annualtzed Costs
    1.  Cpaltal Charges                                           107,400
    2.  Maintenance                                                20,000
    3.  Operating labor                                            4,000
    4.  Utilities                                                  21,200
    5.  Taxes, Insaeance, administrative                           26,400

    Total  Annual1zed Costs                                        179,000
                                    6-42

-------
Pun-of-Pile Triple Superphosphate
    The plant uses the conventional TVA cone process for the pro-
duction of run-of-pile triple superphosphate.  Rated production
capacity is approximately 1200 tons of triple superphosphate per day
(550 T/D P205)-  Actual production averages approximately 800 tons
of triple superphosphate per day.
    Figure 5-10 provides a flow diagram of the operation.  Ground
phosphate rock is contacted with phosphoric acid (54 percent Pp^c)
in a TVA cone mixer.  The resultant slurry is discharged to the den
where solidification of the product occurs.  Cutters are used to
break up the product before it is sent to storage.   A curing period of
approximately thirty days is required to allow the reaction to po to
completion.
    Two initial levels of control will be assumed for the model POP
triple superphosphate plant and retrofit costs estimated for each
case.  Most actual costs should fall somewhere between the two estimates,
Existing Controls (Case A)
    In this case, it is assumed that the plant is in a relatively
good state of repair, that necessary ducting and piping changes are
moderate, and that the existing ventilation system does not require
modification.  Replacement of an existing scrubber is assumed to be
the major item in the retrofit program.
    Gases vented from the cone mixer and the den are currently treated
in a 20,000 cfm venturi, combined with the storage building ventila-
tion stream, and sent to a spray tower.  The storage building ventila-
                           6-43

-------
 tion air is sent directly to the spray tov/er.   This  control system
 has  been in'operation for approximately five years.
     Gypsum pond water serves as the scrubbing  liquid for both the
 venturi  and the spray tower.  Mater is available at  80°F with a fluo-
 ride content (as F) of 0.5 weight percent.   Additional information
 regarding the scrubbing liquid is provided  in  Table  6-7.
     Ventilation flow rates and fluoride concentrations for the
 various  sources are listed in Table 6-23.  The values listed in this
 table are estimates based on source test results and control equip-
 ment design data.   Fluoride removal efficiencies are 86 percent for
 the  venturi  treating the combined cone mixer - den gases and 71 percent
 for  the  spray tcwer.  Total fluoride emissions from  the production
 and  storage facilities are 127 pounds per hour.

 Table 6-23.  FLOW  RATES AND FLUORIDE CONCENTRATES  FOR ROP-TSP
                       PLANT EMISSION SOUPCES19-21
Emission Source
Cone mixer vent gases
Curing belt (den) vent
gases
Storage building vent
gases
	 1
Flow Rate
(SCR1)
50Q
24,500
125,000
Fluoride Concentration
(mg/SCF) (opm)
0.71
95
24
30
4000
1000
Retrofit Controls
    The proposed retrofit  involves  the  replacement of the spray tower
with a spray-crossflow  packed  bed scrubber designed for 9? percent
fluoride removal.   Installation of  the  new scrubber will reduce
                           6-44

-------
 fluoride  emissions  to  4.6  pounds  per  hour.  This emission level is
 equivalent to the emission guideline  of 0.2 pounds  fluoride per ton  P,
 input.
     Moderate rearrangement of  the ductwork  will be  reouired to
 install  the new scrubber.   Existing controls  are located as deoicted
 in Figure 6-8.   The spray  tower vn'll  be removed and the spray-cross-
 flow packed bed scrubber installed in the vacated area.  A  new  fan
 will be  required to compensate for the higher pressure drop of  the
 spray-crossflow packed bed scrubber.   Existing water lines  and  pumps
 will be  used to supply gypsum  oond water at 40 psig to the  spray
 section.   A 16-inch line will  be  required to supply 2400 qom of water
 at 5 psig for the packed bed.   Spent  scrubbing water is to  be re-
 cycled to the gypsum pond  in the  existing drainage  system.   Treated
 gases will be emitted  from a newly installed 75  foot stack.
     Table 6-24 lists the major cost items involved  in the  retrofit
 project.   Operating conditions for the spray-crossflow packed bed
 scrubber are presented in  Table 6-25.  A breakdown  of the  estimated
 cost of the project is orovided by Table 6-26.
 Table 6-24.  MAJOP RETROFIT ITEMS FOP "n*EL MP-TSP PL^NT  (C/V-SE A)

 1    Rearrangement of ductv/ork - removal of  spray tower from service
     and connection of spray-crossflow packed bed scrubber and stack.
     Requirements are 50 feet of 96-inch* duct.
 2.  Water line connecting gypsum pond with spray-crossflow packed
     bed scrubber - 1600 feet of 16-inch pipe.
*flot necessarily circular,  but of equivalent cross-sectional area.
                          6-45

-------
3.  Two centrifugal pumps (one spare) - 2400 gpm,  76 feet total

    dynamic head (TDH), 100-horsepov:er motor.


4.  Removal of spray tower.


5.  Centrifugal fan -  150,000 SCFM,  355 feet TDH, 200-horsepower

    motor.


6.  Spray-crossflow packed  bed  scrubber.  Unit is designed  to

    handle  158,000 acfm.   Using pond water  at specified conditions,

    scrubber  must  reduce  fluoride  concentration to 0.23 mg/scf

     (9.7  ppm) when treating streams  listed  in Table 6-23.


 7.  Stack - 75 f^et  tall, 9 feet  diameter.


 8.   Supports and foundations.


    Table 6-25.  OPERATING CONDITIONS FOR SPRAY-CP.OSSFLOW PACKF.D
                 BED  SCRUBBEP FOP  MOPEL POP-TSP PL^IT, C«?F  «
                           (550 Tons/Day P205)


 Gas to scrubber
     Flow, SCFM                           150,000
     Flow, DSCFM                          145,500
     Flow, ACFM                           158,000
     Temp., °F                            100
     Moisture, Vol. %                     3.0
     Fluoride  (as  F),  Ib/hr               439
     Fluoride  (as  F),  pom                 928

  Gas from scrubber
     Flow.  SCFM                           150,000
     Flow,  DSCFM                          145,500
     Flow,  ACFM                           156,000
     Temp.,  °F                           90
     Moisture, Vol. %                     3.0
     Fluoride (as  F),  Ib/hr              4.6
     Fluoride (as  F),  ppm                9.7
     Fluoride removal,• wt                99.°
     Estimated y1, ppm                   0.8
     Estimated NTU required              4.7

-------
GYPSUM
POND
                1300'
MIXFP TONE AND
DEN VENTILATION
                                                                          STOPARE BUILDINR

I
ion1
i

l>i
POP - TSP
PPODUCTION

L_:_ n nn i 	 ^
|^- -VENTILATION
POP - TSP
STHRAFF

L^ 375' 	 	 \' 	 - >^
     7 - VE.NTURI • SCRUBBER

      c; - SPRAY TOUER SCRUBBER

                    Figure 6-8.   EXISTING  CONTROL EQUIPMENT LAYOUT FOP. ?10PEL pop-TSP PLANT,  CASH A

-------
      Table 6-26.  RETROFIT COSTS FOR MODEL ROP-TSP  PLANT, CASE A
                         (550  tons/day PgOg)  November 1974

                                                                 Cost ($)

A.  Direct Items  (installed)

    1.  Spray-crossflow packed bed scrubber                      294,000
    2.  Ductwork                                                   9.800
    3.  Piping                                                     33,300
    4.  Pumps and motors                                           26,500
    5.  Centrifugal fan and motor                                  28,800
    6.  Removal of old equipment                                   12,500
    7.  Stack                                                      44,000
    8.  Performance test                                           4»000

    Total Direct  Items                                           452,900

B.  Indirect Items

    Engineering construction  expense, fee,interest on
    loans during  construction, sales tax, freight insurance.
    (35% of A)                                                   158,500

C.  Contingency
    (25% of A)                                                   113,200

D.  Total Capital Investment                                     724,600

E.  Annualized Costs
    1.  Capital charges                                          118,100
    2.  Maintenance                                                21,700
    3.  Operating labor                                            4,000
    4.  Utilities                                                  26,500
    5.  Taxes, insurance  administrative                            29,000

    Total Annualized  Costs                                       199,300
                                    6-48

-------
Existing Controls (Case B)
     In th.'  .sse, it is assumed that only the iroduction area is
originally equipped vi th controls.  /* Doyle scrubber is used to
treat the combined ventilation streams from the nixing coni e~J
the den.  Ventilation flov/ rates and fluoride concentrations for
these sources are presented in Table 6-27.  Fluoride removal efficiency
of the Doyle scrubber is approximately 59 percent.  Emissions from the
production area are 95.2 pounds of fluoride pen hour with existing
controls.
     The ROP-TSP storage area is currently uncontrolled.  Estimated
fluoride emissions from this source are 198 oounds oer hour.
Table 6-27.  FLOW RATES AND FLUORIDE CONCENTRATIONS OF EFFLUENT
                    STREAMS SENT TO EXISTING CONTROLS.
Emission Source i
i
Coae mixer vent gases
Curing be 1 t^y en,^ gases ('
Flow Pate
(SCFM)
500
i
14,500 j
i
Fluoride Concentration
(mg/scf) (DOPI)
I
0.71 ! 3^
160 . 68nn
I' II 'I* IH | ' | 111 1 -t'fi 1
Fxetrofit Controls (Case B)
      The  hooding  on  the  curing  belt  is  in  a  poor  state  of  reoair  and
 will  be replaced.  A new hooding  crrangement utilizing  a flat
 stationary air tight top and  plastic side  curtains  will be used.
 The  ventilation rate for the  belt will  be  increased to  24,500  SCFM.
 This higher flow rate will  necessitate  the replacement  of  existing

-------
ductwork and fans.  The mixing cone will continue to be ventilated
at a rate of 500 SCFK.
     Control of emissions  from the storage area requires the
sealing of  the building  (roof monitor  and sides) and the installation
of a ventilation  system  designed  to  handle 125,000 SCFIi.  All
associated  fans,  pumps,  piping,  and  ductwork must be installed.  The
ventilation stream from  the storage  area will  be combined with the
effluent  stream from the oroduction  area and sent to controls.  Flow
rates  and fluoride concentrations associated with the  various  emission
sources are the s ime as  listed in Table 5-23.
      Fluoride emissions must be reduced to 4.6 pounds  per  hour in
order to meet the emission guideline of 0.2 pounds  fluoride per  ton
 P Q  input.  This will be  accomplished by removing  the Doyle Scrubber
  £. J
 and installing a  spray-crossflow packed bed scrubber designed for
 99.3 percent fluoride removal.   Figure 6-9 indicates the placement
 of the retrofit  scrubber.  Treated  gases will be emitted from a  newly
 installed  75-foot stack.
      Gypsum pond water  will  be  used as the scrubbing  liquid.  Pond
 water  characteristics  are listed in Table 6-7.  An 18-inch  line will
 be  installed to supply  the required 3450  gpm  of pond  water.   Spent
  scrubbing  water is to be recycled to the  gypsum pond  in an  existing
  drainage system.
       Table 6-2";  identifies the major cost items  involved  in the
  retrofit project.  Operating'condi  tioris for the hevi scrubber are'
  listed in Table 6-2°   Estimated costs are provided in Table *-3n.
                              6-50

-------
GYPSUM
POilD
V
                "X  1300'
    I
   en
                                                MUER CONE AND
                                                DEN VENTILATION
                                               ROP - TSP
                                              PRODUCTION
                                                 TOO'
                                             STORAGE BUILDING
                                             VpT RATION SYSTEM
                                                                  ROP - TSP STORAGE
                                                                    TOO1

                                                                     i.
                                                                             375'
     SPRAY CROSSFLOW PACKED
     BED SCRUBBER
Figure 6-9.   RETROFIT CONTROL EQUIPMENT LAYOUT FOR MODEL ROP-TSP PLANT,
                                 CASE B
   - STACK

-------
Table 6-2S.   MAJOR RETROFIT ITEMS  FOR  MODEL ROP-TSP PLANT (CASE B)

1.   Ductwork -  replacement of the curing belt ventilation system
     and  installation  of  a  storage building ventilation system.
     Curing  belt ventilation system --175 feet of 42-inch duct
     with  a  50 foot branch  of 6-inch duct connecting the mixing
     cone.   Storage building ventilation system - 150 feet of 96-
     inch  duct with two  160-foot branches of 66-inch duct.
2.   Water line  connecting  gypsum  pond with spray-cro.,sflo;j packed
     bed scrubber - 1700  feet of 18-inch pipe.

3.   Two centrifugal pumps  (one spare)  -  3450  gom,  74 feet
     total dynamic head (TDK),  125-horsepower motor.  Booster pump
     for spray section -  1150 gpm,  81-feet TDH, 40-horsepower motor.

4.   Centrifugal  fan for  curing belt ventilation system - 25,000
     SCFM, 760 feet TDH,  75-horsepower motor.   Fan for storage
     building  ventilation system -  125,000 SCFM, 725 feet TDH,
     350 horsepower motor.

5.   Removal cf  -  1) old  hooding system from curing belt and
     2) 2oyle  scrubber.

6.  Installation of a  new hooding  system consisting of a wooden air-
    tight  top  and plastic side  curtains on the curinc belt.
                          6-52

-------
 7.    Sealing  of the  storage  building  -  roof monitor and sides of

      building.


 8.    Spray-crossflo;/ packed  bed  scrubber.  Unit  is designed to

      handle 158,000  acfn.  Us ing- pond water at specified conditions,

      scrubber must reduce  fluoride  concentration to 0.23 mg/scf

      (9.7 ppm)  when  treating streams  listed in Table 6-23.


 9.    Stack -  75 feet tall, 9 foot diameter.


10.    Supports and foundations.


 Table 6-29.  OPERATING CONDITIONS FOR SPRAY-CRQSSFLOW  PACKED BED
                  SCRUBBER  FOR MODEL ROP-TSP PLANT, CASE B
                          (550 Tons/Day  P0)
 Gas to Scrubber
      Flow, SCFM                   150,000
      Flow, DSCFI1                  145,500
      Flow, ACFM                   158,000
      Temp. , °F                    100
      Moisture, Vol .  %             3.0
      Fluoride (as F), Ib/hr       703
      Fluoride (as F), ppm         1490

 Gas from Scrubber
      Flow, SCFM                   150,000
      Flow, DSCFM                  145,500
      Flow, ACFM                   156,000
      Temp., °F                    90
      Moisture, Vol .  %             3.0
      Fluoride (as F), Ib/hr       4.6
      Fluoride (as F) , ppm         9.7
      Fluoride removal, wt %       99.3
      Estimated y' , ppm            0.8
      Estimated NTU required       5.1
                        6-53

-------
      Table 6-30.  RETROFIT COSTS FOR MODEL ROP-TSP PLANT,  CASE  B*
                         (550  tons/day PgOg)  November 1974

                                                                  Cost  ($)

A.  Direct Items (installed)

    1.  Spray-crossflow packed bed scrubber                       294,000
    2.  Ductwork                                                   89,200
    3.  Piping                                                     39,800
    4.  Pumps and motors                                           35,000
    5.  Centrifugal fans and motors                                40,800
    6.  Curing belt hooding                                        26,700
    7.  Sealing of storage building                                80,000
    8.  Removal of old equipment                                   20,000
    9.  Stack                                                      44,000
   10.  Performance test                                            4,000
   11.  Structural steel supports/bldg.                           100,000

    Total Direct Items                                            773,500

B.  Indirect Items
    Engineering const)uction expense, fee, Interest on
    loans during construction, sales tax, freight insurance.
   • (35% of A)                                                    270,700

C.  Contingency
    (25% of A)                                                    193,400

D.  Total Capital Investment                                    1,237,000

E.  Annualized Costs

    1.  Capital"charges                                           201,600
    2.  Maintenance                                                37,100
    3.  Operating labor                                             4,000
    4.  Utilities                                                  48,200
    5.  Taxes, insurance, administrative                           50,000

    Total Annualized  Costs                                        340,900


*In costing this model, extensive use was made of a project report dated

 June 27, 1974, prepared by Jacobs Engineering company for  J.  R.  Simplot

 Co., Pocatello, Idaho.
                                    6-54

-------
j.-anular Triple Superphosphate Procuctio-'i and Storage
    Tie :iodel slant uses the "5crr-G river process '"or the production
of granular triple superphcschate.  Designed production capacity is
870 tons of triple superphosphate per day (409 T/D P9Cg).  Figure
4-13 orcvides a scnematic diagram of the operation.
    Ground phosphete rock and phosphoric acid (38 percent Pp^c) are
contacted in a series of reactors.  Tha reaction mixture is then
pumped to the granulator <:here it is mixed v:ith recycled material
from the cyclone dust ccllectcrs and the screening operations to pro-
duc-2 product sized granules of triple superphosphate.  A rotary
drier is used to reduce the product moisture content to about 3 per-
cent.
    Dried triple superphosphate is cooled and screened before being
sent to storage.  A curing period of 3 to 5 days is provided before
the product is considered ready for shipping.  Shipping cf GTSP
is on a seasonal basis, therefore, a large storage capacity is re-
quired.  The storage facility has a capacity of 25,000 tons of a
triple superphosphate 01,500 tons PgOg).  This building is venti-
lated at a rate of 75,000 scfm using a roof rronitor.
Existing Controls
    Sases vented from the reactors and the granulator  are  combined
and treated in a tiro-stage system consisting of a  venturi  and  a
cyclonic spray tower.   Gypsum pond -./ater  serves as the  scrubbing
liquid in both units.   Pond v.-ater is available  at  80°F  with a  fluo-
                         6-55

-------
ride content  of  0.5  percent.   Additional properties are listed in
Table 6-7.  Fluoride removal  efficiency  is  83  percent ^or tha ven-
turi scrubber and  82 percent  for  the  cyclonic  spray tower.
    The drier gases  are  passed through cyclones  for product
recovery and  then  treated  for fluoride' removal by a tvio-stage
scrubbing system (venturi-cyclonic  spray toi:er)  similar to that de-
scribed for the  reactor-granulator  cases.   Fluoride collection is 85
percent in the venturi and 86 percent in the cyclonic scrubber.
Gypsum pond water  is used  as  the  scrubbing  liquid.
    Miscellansois  gas streams vented  from the  product cooling and
screening operations are a third  source  of  emissions from ths GTSP
production facility.  These streams are  combined and treated for
product recovery (dry cyclone) and  fluoride removal (cyclonic spray
tower).  Fluoride  collection  efficiency  of  the cyclonic spray tower
is 87 percent.
    Existing  controls have been in  operation for five years.  Flow
rates and^fluoride concentrations for the various emission sources
are listed in Table  6-31.   All values are estimates based on a com-
bination of source test  results and published  data.  Total fluoride
emissions from the production facilities are 31.0 pounds per hour.
    Ventilation  air  from the  storage  building  is presently emitted
uncontrolled.  Table 6-31  lists the estimated  volumetric flov/ rate
and fluoride  concentration based  on source  test  data.  Fluoride
emissions from the storage building'are  13.2 pounds per hour.
                           6-56

-------
Table 6-31.  FLOI' RATES AND FLIDPIDE CCSCENTP*.TIONS FOR GTSP PLA.'J
                          EJ'ISSKT! SCURCES22-24
I.-.iission source
P.eactor-granulator gases
Drier vent gases
Cooler S screening equip-
ment gases
Storage building ventilation
Flow rat*
(SCF")
18,000
48,000
51 ,000

75,000
Fluoride concentration
(rcg/SCF) (cr>n)
84
84
16.8

1.3
3500
3500
700

54
Retrofit Controls
    The retrofit project for the GTSP production facility  involves
tha replacement of the  cyclonic scray tover on the reactor-granula-
tor stream  and on the drier stream vnth  a  spray-crossflov;  packed  bed
scrubber.   £  third spray-crossflow packed  bed unit will  be installed
on the miscellaneous stream to provide  secondary scrubbing.   The
  A
new control system is designed to reduce fluoride emissions  from  the
production  operation to 3.34 pounds  per hour.  This  emission rate is
 equivalent to the emission guideline of 0.2 pounds fluoride per  ton
input.
     Figure  6-10  shows the  position  of existing  controls.  Retrofit
plans call  for the  removal of  the  cyclonic spray  towers treating  the
reactor-granulator  and  the drier gases and the  installation of spray
crossflow necked bed  scrubbers in  the vacated areas.  The soray-
 crossflo1./ packed bad  scrubcer for the piscellaneous stream ---ill
 oe located adjacent to  the preliminary scrubber as indicated in
 Ficure 6-11.                 6-5/

-------
GYPSUM
POND
01
00
               1200'
DRIER
                                                MISCELLANEOUS

                                                       	®
   GTSP

   PRODUCTION
                                                                STACK
     GTSP
  J
HH   STORAGE
                                                                                                  \
                                                                                                 125'
                                                                                                  1
                                           REACTOR - GRANULATOR
                                                            k-
        —  Venturi Scrubber

        —  Cyclonic Scrubber
                                  FIGURE 6-10.  EXISTING CONTROL EQUIPMENT LAYOUT  FOR MODEL  GTSP PLANT.

-------
    GYPSUM
    POND
(Tl
I , '
cn
                  1200'
                                              MISCELLANEOUS

                                         DRIER   ^°  ET°    ^  STACK
GTSP

PRODUCTION
GTSP
STORAGE
T
                                                                                                       125'
                                                                                                      1
                                                 REACTOR-GRANULATOR

                                                -150-
                                 300'
                 O  —    CYCLONIC SPRAY TOWER


                 v 	   VENTURI  SCRUBBER


                 D 	   SPRAY CROSS-FLOW  PACKED BED SCRUBBER


                                        FIGURE 6-11.   RETROFIT CONTROL  EQUIPMENT  LAYOUT  FOR  MODEL  GTSP  PLANT.

-------
    Existing pumps,  fans, piping and ductwork will be utilized
wherever possible.   The existing piping system will be used to
supply water to  the  three preliminary scrubbers and the spray
sections of the  secondary (spray-crossflow packed) scrubbers on the
reactor-granulator and the drier streams.  Some minor alteration in
the piping arrangement will be required because of changes in the
scrubber geometry.   A 16-inch line will be installed to provide ?]6p
gpm of water at  5 psig for the spray-crossflov packed bed unit on tfja
miscellaneous stream and the packed sections of the secondary scrub-
bers on the reactor-granulator and the drier streams.  Duplicate
pumps, one on stand-by, will be provided for this service.  In all
cases, the spent scrubbing liquid will be recycled to the gypsum
pond using the existing plant drainage system.
    Some alteration  of existing ductwork will be required to install
the retrofit scrubbers.  A new fan will be installed on the miscellaneous
stream to compensate for the pressure loss caused by the secondary
scrubber.
    Control of emissions from the GTSP storage facility requires
the sealing of the roof monitor and the installation of 350 feet of
ventilation ducting.  Ventilation air will be treated in a spray-
cross flow packed bed scrubber before being emitted.  The unit is
designed to reduce fluoride emissions to 1.25 pounds per hour; a rate
equivalent to, emission guideline under most conditions.  All associated
fans, pumps, piping, and ductwork must be installed.  The existing plant
                           6-60

-------
drainage system will be used to recycle gypsum oond water.
Fiaure 6-11 provides a vie*-/ of the equipment layout.
    All major retrofit items are tabulated in Table 5-32.
Table 6-33 provides a list of operating conditions for the  four
retrofitted spray-crossflow packed bed scrubbers.   Table 6-34 pre-
sents the retrofit project, costs.
Table 6-32.  WUOR RETROFIT ITE'IS FOP. MODEL GTSP PLANT
GTSP Production
1.  Rearrangement of ductwork - removal of existing cyclonic scrubbers
    on reactor-granulator and drier streams and connection  of
    replacement spray-crossflow packed bed scrubbers.  Installation
    of third spray-crossflov packed bed unit on miscellaneous
    stream.  Requirements are 150 feet of 60-inch diameter  duct and
    50 feet of 42-inch duct.
2.  New water line connecting gypsum pond with retrofitted  scrubbers -
  * 1200 feet of 16-inch pipa with 200-foot branch of 14-inch pipe
    to scrubbers treating the drier and miscellaneous streams and 150
    foot branch of 5-inch pipe to the reactor-granulator scrubber.

3.  Two centrifugal pumps, each  2160 gpm, 105 feet total dynamic
    head (TDH), 100-horsepower motor.  Booster pump for spray
    section of spray-crossflow packed bed scrubber on rriscellaneous
    stream - 374 gpm, 89 feat TDH, IC-horsepower motor.
                         5-61

-------
Table 6-32.  MAJOR RETROFIT ITEMS FOR MODEL 6TSP PLANT (cont.)
4.  Centrifugal fan for miscellaneous stream - 51,000 scfm,
    356 feet TDK, 75-horsepower motor.
5.  Removal of cyclonic scrubbers on reactor-granulator and
    miscellaneous streams.
6.  Three  spray-crossflow packed bed scrubbers.  Design parameters
    are provided in Table 6-33.  Using pond water at specified
    conditions, the scrubbers are required to meet the indicated
    emission levels when treating the gases described in Table 6-31.

7.  Supports and foundations.

GTSP  Storage
1.  Sealing of roof monitor and  installation of ducting -  350 feet of
    78-inch ducting for ventilation  of building and  connection of
    scrubber.
Z.  Water line connecting  gypsum pond with spray-crossflow packed
     bed scrubber - 1700 feet of  12-inch  pipe.
3.   Centrifugal pump - 1730 gpm, 81  feet TDH,  60-horsepower motor.
     Booster pump for spray section - 580 gpm,  89  feet TDH, 15-
     Korsepower motor.
 4,   Centrifugal fan r 75.000 scfm, 630 feet TDH,  200 horsepower
     motor.
                            $-62

-------
Table 6-32.  MAJOR RETROFIT ITEMS FOR MODEL GTSP PLANT (cont).

5.  Spray-crossflow packed bed scrubber.   Using specified pond
    water, scrubber must reduce fluoride  concentration of venti
    lation stream to 0.13 mg/scf (5.1) when treating the gases
    described in Table 6-31.

6.  Supports and foundations.

7.  Stack - 50 feet tall, 6 foot diameter.
                     6-63

-------
   Table  6-33.
OPERATING CONDITIONS FOP SPP.AY-CROSSFLOW
PACKED BED SCRUBBERS FOP flODEL  GTSP  PLANT
        (400 Tons/Day P2^5)
-3 to Scrubber

   Flow, SCFM
   Flov, PSCP'
   Flow, ACFfl
   Tenp., °F
   Moisture, vol. *
   Fluoride  (as  F),  Ib/hr
   Fluoride  (as  F),  ppm

 Gas  from  Scrubber

    Flow,  SCFil
    Flow,  DSCFf
    Flew,  ACR1
    Temp., °F
    !ioisture, vol. %
    Fluoride (as F), Ib/hr
    Fluoride,, (as F), ppm
    Fluoride removal , wt %
    Estimated y1, ppm
    Estimated MTU required
Product!
Reactor
18,000
16,560
19,^00
110
8.0
28
490
16,850
16,560
17,500
°0
2.0
1.00
17.5
96.5
n.n.5
3.38
on
Drier
48,000
44,160
52,500
120
8.0
79.8
525
45 ,050
44,160
46,800
90
2.0
1.76
11.5
97.8
0.95
3.90

Cooler
51 ,000
48,450
54,900
no
5.0
14.8
92
49,400
48,450
51 ,200
90
2.0
0.63
3.9
96.0
^.85
3.39
Storaos
"entilation
75,000
74 ,480
77,100
87
0.7
13.2
54.1
76 ,000
74,480
78,100
85
2.0
1.25
5.1
90.5
0.7
2.49
                                 6-64

-------
                  Table 6-34.   RETROFIT COSTS FOR MODEL
                  GTSP PLANT  (400 tons/day P205) November  1974

                                                                    Cost ($)
 A.   Direct Items  (installed)                                        	""•

     1.   GTSP Production
         a.   Spray-crossflow packed  bed scrubbers (3)                261,000
         b.   Ductwork                                                 22,800
         S-   "P1nS  J                                               26,200
         d.   Pumps and, motors                                         19,700
         e.   Removal of old  equipment                                 18*000
         f.   Performance test                                          4*.000
         g.   Centrifugal  fan and motor                                14*400
     2.   GTSP Storage  '                                                 '
         a.   Cross flow packed scrubber                             150  000
         b.   Ductwork                                                 56'600
         c.   Piping                                                   27,800
         d.   Pumps and  motors                                         15J200
         e.   Centrifugal  fan and motor                                23*000
         f.   Structural  steel supports/bldg.                          50*000
         g.   Sealing of storage building                              10,000
         h.   Performance  test                                         4,000

         Total Direct  Items                                          702,700

B.   Indirect  Items

     Engineering construction expense,  fee, interest on
     loans during construction, sales tax, freight insurance.
     (35% of A)                                                     245,900

C.  Contingency
     (25% of A)                                                     175j700

D.  Total Capital  Investment                                     1,124,400

E.  Annualized Costs

    1.   Capital  charges                                            183,300
    2.   Maintenance                                                  33 300
    3.   Operating  labor                                              6*000
    4.   Utilities                                                    ^O
    5.   Taxes, insurance, administrative                            44,900

    Total Annualized Costs                                         308,600
                                 6-65

-------
6.1.3.2  Retrofit Case Descriptions
General Procedure
     This section describes two actual cases in whlcii control
systems containing spray-crossflow oacked bed scrubbers were added to
existing production'facilities.  Each case description provides the
following information:
     1.  A description of the process in use,
     2.  Identification of the original fluoride controls and sources
         treated,
     3.  A description of the retrofit project, and
     4.  Retrofit costs.
Case A
     Case A involve&*
-------
 Original  Controls
      Fluoride  control  was  initially  provided  by  a  spray towor installed
 in  1953 as  part  of  the orioinal  plant  desicn.  Gypsum oond water was used
 as  the  scrubbing liquid.   Ventilation  streams from the drier and the
 product screens  were sent  to the spray tower while both reactor and
 granulator  gases were  vented directly  to the atmosnhere.  The sprav
 tower was improved  in  1964 by the addition of more sprays and a mist
 elimination section.   Performance data  for this  system is not available.
 Retrofit Controls
     The spray tower was removed in 1966 as part of a retrofit project
and replaced by a three stage scrubbina system.  Gases vented from the drier
(60,000 acfm) and the screens (40,000 acfm) are now treated in seoarate. venturi
scrubbers, combined, passed through a cyclonic scrubber, and finally
treated in a spray-crossflow packed bed scrubber.  Operating characteristics
of these units are listed in Table 6-35.  Pond water serves as the
scrubbing liquid for the entire system.  Controls for the reactor and the
granulator were not added at this time.
        *t
     All associated fans, pumps, piping, ductwork, and stacks were installed
as part of the retrofit project.  New pond water supply and drainaqe svstems
were also required.
     Designed fluoride removal  efficiency is 99+ percent.   Tests
conducted by the Environmental  Protection Aqency in June 1972 measured
fluoride removal  efficiencies  ranqino uo to 99.6 percent.
                                   C-67

-------
Table  6-35.   OPERATING CHARACTERISTICS  OF  SCRUBBERS  IN RETROFIT C^SE A
Scrubber  type
Scrubbing liquid
to gas ratio (pal/SCF)
Gas stream
pressure drop(in.  H20
Drier venturi
Screen venturi
Cyclonic scrubber
Spray-crossflow
packed bed scrubber
      0.008
      0.006
      0.007
      0.002
    12-15
     8-13
     4-6
     2-6
Retrofit Costs
     Total installed cost of the retrofit control equipment was $368,000,
however, this does not  include the cost of removing old eouipment or of
adding new pond water supply and drainage systems.  The annual  operating
cost is reported to be  $51,000.
Case B
     Case B is similar to Case A in most respects.  The facility involved
is a granular triple superphosphate plant built in 1953.  This plant also
uses' the Dorr-Oliver process for GTSP.  Annual capacity is approximately
200,000 tons triple superphosphate.  Space limitations are similar to those
described in Case A.
                                 6-68

-------
Original Controls
     Emissions from the drier and the screening area ware controlled bv
a spray tower which had been installed as part of the original  plant
design.  Fluoride removal  efficiency data is not available for this system.
Reactor and granulator gases were vented to the atmosphere without treatment.
Retrofit Controls
     The retrofit project consisted of the removal of the spray tower and
its replacement by a system similar to that described in Case A.  Controls
are in three stages - 3 Venturis in oarallel followed by a cyclonic scrubber
and a spray-crossflow, packed bed scrubber.  Effluent streams from the drier
and the screens are treated in separate Venturis, combined with the oases
from the third venturi, and sent to the remaining controls.  The third
venturi treats gases from either an adjacent wet acid olant or a nearby
run-of-pile triple superphosphate plant.  Designed capacity of the control
system is 115,000 acfm.  Gypsum pond water serves as the scrubbina liquid.
Controls for the reactor and the aranulator v/ere not installed as a part of
this project.
     The retrofit controls were added in 1972.  All associated fans, pumps,
piping, and ducting were installed as part of this project.  Fluoride removal
efficiency of the system is reported to be 99+ percent.

Retrofit Costs
     Total installed cost for the retrofit controls was reported to be
$760,000.  Table 6-36 lists a breakdown of the cost.  Demolition costs
and the cost of adding new pond water supnlv and drainage systems are
not included.  i!o ooeratinn costs v/ere provided.
                               r-fg

-------
          Table 6-36.  CASE B RETROFIT PROJECT COSTS
         Item
Installed  Cost
   (dollars)
Foundations
Structural steel
Blowers and motors
Wet scrubbers
Pumps, sumps and piping
Ducts and stack
Electrical and instruments
     81,000
     52,000
     85,000
    218,000
    175,000
    102,000
     47,000
                               6-70

-------
  6.2   VEi.'TURI  SCRUBBER

  6.2.1  Description
       Venturi  scrubbers are primarily participate collection devices,
  however, tney are also applicable to .gas absorption work and are in
 widespread use throughout the phosphate fertilizer industry.  They are
 particularly well suited for treating effluent streams  containing large
 amounts of solids or silicon tetrafluoride because of their high solids
 handling capacity and self-cleaninn characteristics.  Operational  reliability
 and low maintenance requirements  are major reasons for  the  popularity  of
 this  scrubber design.
      A venturi provides  a high  degree of gas-liauid nixing  but  the
 relatively  short  contact time and the cocurrent  flow  of the scrubbing
 liquid tend to limit  its  absorption  capabilities.   When  treating  effluent
 streams requiring  a high  degree of fluoride  removal,  Venturis are  often
 used  as the initial component in  a multiple-scrubber  system.
      Two types of  venturi scrubbers, gas actuated and water actuated,  are
 in general  use.  In both cases, the  necessary gas-liquid contacting is
obtained from  velocity differences between the two phases and turbulence
in the venturi throat.  Both types also reouire the use of a mist elimination
section for removal of entrained scrubbing liquid.  The ma.icr difference
between the designs is the source of motive power for oneratinq the scrubber.
In the cast of the gas actuated  venturi, the velocity of the gas stream
provides the energy required for gas-liauid contacting.   The scrubbino
liquid is  introduced into the oas  stream at fie throat of the venturi
                                 71

-------
 and  is  broken into fine droplets  by the  acceleration cas
 stream.   Pressure drop across the scrubber  is generally high - from
 8  to 20  inches  of water.   A fan  is required to compensate for this
 loss in  gas  stream pressure.   Figure 6-12 provides a schematic
 diagram  of a gas  actuated  venturi.
      A water acutated  venturi is  pictured in Picture 6-13.  In this
 case, the scrubbing liquid is introduced at a high velocity through
 a  nozzle located  upstream  of  the  venturi throat.  The velocity of the
 water streams is  used  to pump the effluent  gases through the venturi.
 Drafts of up to 8 inches of water can be developed at hi oh liauid
           25
 flow rates.
      The removal  of the fan from  the system makes the water actuated
 venturi  mechanically simpler, more reliable, and less  costly
 than the gas  actuated type. An additional advantaae is its relative
 insensitivity to  variations in the gas stream flow rate?6   Gas
 actuated Venturis rely upon t^e gas  stream  velocity for the energy
 for  gas-liquid  contacting,  therefore, variations in the aas flow can
 greatly  affect  scrubber efficiency.  The performance of the water-
 actuated venturi  depends mainly on  the liquid strean- velocity.
     Water actuated  Venturis  find  application Drincioally as aas
                25
absorption units.    Their  use is  usually linited, however, to  small
gas  streams with  moderate scrubbing  requirements.  The water-actuated
venturi   is seldom used  for  gas flows greater than 5,000 ac^m because
                                2fi
of tne large water retirements.
                              5-72

-------
                AIR
                INLET
            WATER
            INLET
            VEMTURI
                          AIR
                          OUTLET
                              CYCLONIC
                              MIST ELIMINATION
                              SECTION
                                            WATER
                                            OUTLET
FIGURE  6-12.  GAS ACTUATED VENTURI  SCRUBBER WITH CYCLONIC MIST ELIMINATOR.
   SPRAY
   NOZZLE
               AIR
               OUTLET
                              WATER
                              INLET
                                              AIR
                                              INLET
                                             SEPARATOR
                                       WATER
                                       OUTLET
  FIGURE  6-13.
WATER ACTUATED VENTURI.


                6-73

-------
6.2.2  Emission Reduction
     No wet-acid plant using a venturi scrubber was tested by the
Environmental Protection Agency, however, fluoride absorption efficiency
ranging from 84 to 96 percent have been reported for water-actuated
                                               27
Venturis treating wet-acid plant effluent gases.  Performance data was
obtained for venturi scrubbers installed in superphosphoric acid and
diammonium phosphate plants.  This infornation is presented in Table 6-37.
Several additional plants  (DAP, GTSP, ROP-TSP) were tested at which venturi
scrubbers were used as the preliminary scrubber in a two or three staqe
system.  Performance data for the overall systems are presented in Tables
6-3 and 6-40.
Table 6-37   VENTURI SCRUBBER PERFORMANCE IN SUPERPHOSPHORIC ACID AND
             DIAMMONIUV PHOSPHATE PLANTS 28
Type of plant
Vacuum evapora-
tion SPA
DAP
Sources controlled
barometric conden-
ser, hotwell , and
product cooling tank
reactor, granula-
tor, drier, and
cooler
Control
system
water
actuated
venturi
3 gas
actuated
Venturis
in para-
llel
Scrubbing
liquid
pond
water
weak acid
(20-22%
W
Fluoride emissions3
(Ib F/ton P205)
0.0009
0.129
 Average  of testing results
                                  5-74

-------
6.2.3  Retrofit Costs for Venturi  Scrubbers
     This section evaluates the costs involved  wit:-,  retrofittlnp
venturi scrubbers in a diammonium phosohate  plant.   Venturis
might be used to provide fluoride control  for this  source  because
of their high solids handling capaJilitv.   Cnlv the  ret.rrfi':  model
approach will be used to provide costs.
     The model plant is the same as described in section 6.1.3.1.
To avoid repetition, only a summary of retrofit controls,  e list
of major retrofit items, and a Dreakdov:n of costs rill  be  orasented
here.
     The general aspects of the retrofit project are the same as
described in Section 6.1.3.1.  Gas-actuated Venturis will  be used
as fluoride scrubbers on the reactor-granulator, the drier, and
the cooler streams.  Pumping and fan requirements differ from those
presented in section 6.1.3.1.  An existing line win be used to
supply part of the water requirement.  Table 6-38 provides a list
of major retrofit Items required.  Costs are presented in Table
6-39.
      Table 6-3S.  flAJOR RETROFIT ITEMS FOR MODEL DAP PLANT

1.   Ductwork - removal of cyclonic  spray tower from service and
     connection of three gas-actuated  venturi  scrubbers.  Reauire-
     ments are 100 feet of 50-inch duct and 50 feet of 54-inch duct.

2.   Hater line connecting gypsum pond with venturi scrubbers -
     1200 feet of 16-inch pipe with  200-foot branch of H-inch
                             6-75

-------
     pipe and 150-foot branch of 6-inch cine.
3.   Two centrifugal Dunns (one spare) - 2550 gorc, 195
     feet total dynamic head (TDK), 150 'lorsenower rotor.

4.   Three centrifugal fans: one for the reactor-oranulator
     stream, one for the dri?r stream, and one for the cooler
     stream.  Peactor-granulator fan - 30,000 scfm, 713 feet TDH,
     75 horsepower motor.  Drier stream fan and cooler stream
     fan - 45,000 scfm, 713  feet TDH,  125 horsepower rotor.

5.   Removal of cyclonic  spray tower.
6.   Three venturf  scrubbers equipped  with mist eliminator
     sections.  When  using specified pond water and treatino
     gases described  in Table  6-19, scrubbers are  reouired to obtain
     performance  indicated in  Table 6-21.

7.   Supports  and foundations.

-------
    Table  6-39.   RETROFIT COSTS FOR MODEL DAP PLANT
                  (500 Tons/Day P205) November 1974


                                                Cost ($)

A.  Direct Items (installed)

    1.  Venturi  scrubbers (3)                     17  000
    2.  Ductwork                                  26'500
    3.  Piping                                    32  300
    4.  Pumps and motors                          ^p» ww
    5.  Centrifugal fans and motors               «
      .
    6.  Removal of old equipment                     QQQ
    7.  Performance test                           H'u

    Total  Direct  Items                           312,400

 B.   Indirect Items
     Engineering  construction  expense,
     fee,  interest on  loans  during
     construction, sales  tax,  freight
     insurance (35%  of A.)                         109>JUU

 C.  Contingency (25% of A.)                       78'100

 D.  Total Capital Investment                     499,800

 E.  Annual!zed Costs

      1.  Capital  charges                           81,500
      2.  Maintenance                                -'OQQ
      3.  Operating labor                           31'000

      5:  ^'insurance,  administrative          20^,000

      Total Annualized Costs                       151,500
                           6-77

-------
5.3  SPRAY TOl'ER  SCRUBBER

6.3.1   Description
     Spray towers provide  the  interonase contacting necessary for
gas absorption  by dispersing the scrubbing liouid in the gas phase
in the  form of  a  fine spray.   Several types of spray towers are in
general use.  The simplest consists of an empty tower equipped with
liquid  sprays at  the top and a pas inlet at the bottom.  Scrubbing
liquid  is sprayed into  the gas stream and droplets fall by -jravity
through a upv/ard  flow of gas.   This design has the advantages of a
very low pressure drop  and an  inexpensive construction cost but it can
provide only about ons  transfer unit for absorption.    Entrainment of
scrubbing liquid  is also a problem.
     Cyclonic spray towers eliminate the excessive entrainnent of
scrubbing liquid by utilizing  centrifugal force to remove entrained
droplets.  Figure 6-14  is  a schematic diagram of a typical desicm.
In this case  a tangential  inlet ifused to.impart'the spinning
motion  to the gas stream.   Water sprays are directed parallel to the
gas flov: providing crossflow contacting of the gas and liquid streams.
Pressure drops  across the  scrubber ranges from 2 to 8 inches of water.
Solids handling capacity is high, however, a'.sorptic/1. caoacity is
                                    29 ?0
limited to about two transfer  units.  '
6.3.2   Emission Reduction
     Fluoride removal efficiencies ranging from 84 to 95 percent have
been reported for cyclonic spray towers treating wet acir* plant
                            6-78

-------
                                    CLEAN GAS OUT
                       GAS IN
                       CORE BUSTER DISK






                        SPRAY MANIFOLD






                          DAMPER
                                   WATER WATER

                                   OUT   IN
            FIGURE  6-14.   CYCLONIC SPRAY TOWER SCRUBBER.
               31
effluent nases.    Table 6-40 presents nerformance data obtained bv



the Environmental Protection Anencv for cvclonic soray tov/ers  installed



in wet-process phosphoric acid, diannoniun ohosohate, and  run-o^-oile



triple1 superphosphate plants.  In most cases, the control  system con-



sisted o^ a primary venturi scrubber or cyclonic sorav tower followed



by a secondary cyclonic spray tower.  Gypsum oond water was used as



the scrubbing solution except where indicated.





6.3.3  Retrofit  Costs for Cvclonic 5-irav Towers



     This section will use the retrofit model approach to  estimate



the costs involved with the installation of 'cyclonic  snrav tov/ers  in



? nOD-TSD olant.  Control svstems utilizing cyclonic  snrav tov/ers  are



canable of providinn the collection efficiency  necessary  to reet



the emission guideline of 0.2 pounds fluoride per ton PpCv input.



                            f>-79

-------
                     Table 6-40.  CYCLONIC SPRAY TOWER PERFORMANCE IN WET-PROCESS PHOSPHORIC ACID,
                                 DIAMMONIUM PHOSPHATE, AND RUN-OF-PILE TRIPLE SUPERPHOSHATE PLANTS
     Type of plant
Sources controlled
Primary controls
Secondary controls    :luoride emissions9
                                                                                         Ib F/ton P205)
en
oo
o
     WPPA


     DAP
      ROP-TSP
      ROP-TSP
reactor, filter, and
miscellaneous sources

reactor, granulator,
drier, and cooler
mixing cone, den,
transfer conveyor,
and storage pile

mixing cone, den,
and storage pile
two-stage cyclonic
spray tower

3 cyclonic spray
tower scrubbers in
parallel.  Scrub-
bers treating re-
actor-granular
and drier gases
use weak (28-30%
P205) acid

venturi scrubber
2 cyclonic spray
tower scrubbers
in parallel
2 cyclonic spray
tower scrubbers in
parallel treating
reactor-granulator
and drier gases
cyclonic spray tower
scrubber with packed
bed section

2 cyclonic spray tower
scrubbers in parallel
0.056


0.380
0.19/K 0.21V
                                                                                            OJ25
      aAverage  of  testing  results

      bSecond series  of tests

-------
     The nodal plant is tne sane as described in section 6.1.3.1
(Case /"•).  How rates and fluoride concentrations of the various
effluent streams ere listed in Table 6-23.  -ases venter1 from ti-,e
cone rrixer and den are presently treated in a 20,000 cfm ver.turi,
combined with the storaqe buildinn ventilation stream and sent to a
spray tov/er.  The storaae buildino ventilation air is sent directly
to the spray tower.  Total fluoride emissions are 127 oounds oer
hour with existinp controls.
     The'retrofit project involves the removal of the existinn scrubbers
and the  installation of a new control system consist!"nq of orelim.inarv
cyclonic spray towers  on the ventilation streams *rom the production
and storage areas followed by a secondary  cvclonic sprav tower  treatino
the combined effluent  streams.  This system will reduce fluoride
emissions to 4.6 pounds per hour which is  equivalent to the  emission
 guideline.
     -Retrofit controls will be located as  shown in Flrure 6-15.  Mod-
erate rearrangement of the ductwork is necessary to install  the
cyclonic spray towers.  Two new fans will  be required because o* the
higher pressure drop associated with the retrofit system.  Fxistino
water lines and numps  will be use^ to supply the orelirinarv scrubbers.
A 14-inch line will be installed to provide  1725 cipn of oond water
for the  secondary scrubber.  Scent scrubbino v/ater will be recvcled
to the ayosum pond  in  the existina drainage  svsteir.  Treated oases
will be  emitted from a newly installed 75  foot  stacK

                         F-81

-------
HYPSUM
POND
 cr>
  i
 oo
 ro
                  .1300'
MIXEP. CONE AND
DEN VENTILATION
  STORAGE  PUILDIMR
/VENTILATION

pvnP_T$p
PRODUCTION
1 ^ -i nn 1 	 »j

pnp-TSP
STORAGE
rf __ 77R1 	 T"
f
inn1
1

           O —  CYCLONIC SPRAY TCWEP. SCRUBBER

                 Fiqure 6-15.  RETROFIT CONTROL EOUIPMENT LAYOUT FOR MODEL  RO^-TSP  PLANT,

-------
     Table 6-41 lists the major cost items involved in this retrofit
project.  Operating conditions for the three cyclonic spray towers are
provided in Table 6-42.  Retrofit costs are estimated in Table 6-43.

Table 6-41.  MAJOR RETROFIT ITEMS FOR MODEL ROP-TSP PLANT

1.   Rearrangement of ductwork - removal  of venturi and spray tower
     from service and connection of three cyclonic spray towers and
     stack.  Requirements are 50 feet of 42-inch duct and 125 feet
     of 96-inch duct.

2.   Water line connecting gypsum pond with cyclonic spray tower
     treating the combined effluent streams from the production and
     the storage area - 1600 feet of 14-inch pipe.

3.   Centrifugal pump - 1725 gpm, 167 feet total dynamic head (TDH),
     125-horsepower motor.

4.   Removal  of venturi and spray tower.

5.   Centrifugal fan for the storage building ventilation system -
     125,000  SCFM, 514 feet TDH, 250 horsepower motor.  Centrifugal
     fan for  the combined effluent streams - 150,000 SCFM, 461 feet
     TDH, 175 horsepower motor.

6.   Three cyclonic spray tower scrubbers.  When using pond water
     specified in Table 6-7 and treating  the effluent streams described
     in Table 6-23, scrubbers are required to obtain the performance
     indicated in Table 6-42.
                            6-83

-------
7.   Stack - 75 feet tall, 9 feet diameter.
8.   Supports and foundations.
Table 6-42.
OPERATING CONDITIONS FOR CYCLONIC SPRAY  TOWER  SCRUBBERS
         FOR MODEL ROP-TSP PLANT
           (550 Tons/Dav P00C)
                          2 b
                         Mixing cone and den
                         ventilation stream
Gas to scrubber

   Flow, SCFM
   Flow, DSCFM
   Flow, ACFM
   Temp., "F
   Moisture, Vol. %
   Fluoride Gas F), Ib/hr
   Fluoride (as F),
       ppm
Gas from scrubber
   Flow, SCFM
   Flow, DSCFM
   Flow, ACFM
   Temp., °F
   Moisture, vol. %
   Fluoride (as FL Ib/hr
   Fluoride (as F), ppm
   Fluoride removal, wt %
   Estimated y*, ppm
   Estimated NTU required
25,000
24,500
28,400
   140
     2
   307
 4,000
                 25,300
                 24,500
                 27,500
                    115
                      3
                   20.5
                    260
                     93
                    0.8
                    2.7
                                   Storage building    Combined
                                   ventilation stream  streams
125,000          150,000
122,500          1*5,500
128,200          154,000
     85               85
      2                3
    396             50.5
  1,000              107
                     126,000          150,000
                     122,500          145,500
                     128,500          153,000
                          80               80
                           3                3
                          30              4.6
                          76              9.7
                        92.5               91
                         0.8              0.8
                         2.6              2.5
                           8-84

-------
     Table 6-43.   RETROFIT COSTS  FOR  MODEL  ROP-TSP  PLANT
                  (550 Tons/Dav P2°5)  November 1974


                                                 Cost  ($)

A.  Direct Items  (installed)

    1.  Centrifugal  spray tower scrubbers  (3)     300,000
    2.  Ductwork                                   25,000
    3.  Piping                                    29,100
    4.  Pump and  motor                            19,100
    5.  Centrifugal  fans and  motors               54,400
    6.  Removal of old equipment                  12,500
    7.  Stack                                     44,000
    8.  Performance test                           4,000

    Total Direct  Items                           488,100

B.  Indirect Items
    Engineering construction  expense,
    fee, interest on loans during
    construction, sales tax,  freight
    insurance (35% of A.)                        170,800

C.  Contingency (25% of A.)                      122,000

D.  Total Capital Investment                     780,900

E.  Annualized Costs

    1.  Capital charges                          127,300
    2.  Maintenance                               23,400
    3.  Operating labor                            6,000
    4.  Utilities                                 48 ',600
    5.  Taxes, insurance, administrative          31,400

    Total Annualized Costs                       236,700
                           6-85

-------
6.4   IMPINGEMENT SCRUBBER
      Impingement scrubbers are primarily participate collection
devices but they also possess some absorption capability and have
been  used with  limited success to treat effluent  streams from wet-
process acid and diammonium phosphate plants.  The  Doyle scrubber
pictured in Figure 6-16  is the type most commonly used  by  the
fertilizer industry.
          Al* LOCK RELEASE


                                                    ELIMINATOR
                                                    LIQUID INLET
                  FIGURE  6-16.   DOYLE  SCRUBBER.
     Effluent gases are introduced into the scrubber as shown in
Figure 6-11.  The lower section of the inlet duct is equipped with a
axially located cope that causes an increase in  gas stream velocity
prior to its impingement on the surface of the pond.  The effluent
gases contact the pool  of scrubbing liquid at a  hinh velocity and under-
go a reversal in direction.  Solids impinge on the liquid surface and
are retained while absorption of gaseous fluorides is promoted by the
interphase mixing  generated bv impact.   Solids  handlinq capacity is
                                                     33
high, however, absorption capability is very limited.
                             6-86

-------
 6.5  SUMMARY  OF CONTROL  OPTIONS
      Sections 6.1  through  6.4  have examined the operational charac-
 teristics  of  several  scrubber  designs commonly used in the phosphate
 fertilizer industry.  Only the spray-crossflow packed bed scrubber is
 capable  of providing  the degree of fluoride control required to meet
 SPNSS emission  levels in all cases.  In certain cases, cyclonic spray
 tower scrubbers will meet  the  standards, but only at a higher cost as the
 RDlMSf  rdti«of1t example Illustrates (Table 6-44).  Although retrofit
 costs  for  installing venturi scrubbers in a DAP plant were lower than
 those  for  spray-crossflow  packed bed scrubbers, there is no data
 available  which substantiates  that a venturi scrubber alone can achieve
 SPNSS  emission levels.   The primary value of venturi scrubbers in
 fluoride control is their  higher solids handling capacity.  This feature
 is exploited  in several   spray-crossflow packed bed scrubber designs
which  Incorporate a preliminary venturi  scrubber.

Table 6-44.  ESTIMATED TOTAL CAPITAL INVESTMENT AND ANNUAL IZED COST
             FOR DAP AND ROP-TSP RETROFIT MODELS USING SPRAY-CROSS-
                  FLOW PACKED BED AND ALTERNATIVE SCRUBBERS.
                              November  1974.
Facility      Type of Scrubber Capacity      Total Capital   Ann ua 11 zed
                               (tons/day      Investment       Cost
DAP
DAP
ROP-TSP
Spray-crossflow
packed bed
Venturi
Spray-crossflow
	 __•_•• •
500
500
550
$659,100
499,800
724,600
$179,000
151,500
199.300
              packed bed
ROP-TSP       Cyclonic spray      550           780,900       236,700
              tower
                             6-87

-------
 6.6  DESIGN, INSTALLATION, AND STARTUP TIMES
      This section discusses the time required to procure and install
 a wet scrubber on a phosphate fertilizer operation.   Actual  time
 requirements can vary tremendously depending upon such factors as
 space limitations, weather conditions, lack of available utilities,
 delayj in equipment delivery, and lack of engineering data.   The
 Information presented in this section,-has to a limited extent,
 attempted to take such factors into consideration.   Since these
 estimates are general, however,  they should be used  primarily as a guide*
 Hne  and  may be modified as  dictated by specific  circumstances.
      Figure 6-17 identifies  the various steps  involved in the procurement and
installation of a wet  scrubber on a wet-process phosphoric acid plant.  It
also  provides an estimate of the total time requirement of the project.  In
estimating this time requirement, it was assumed that those activities leadina
up to the finalization of control equipment plans and specifications  had been
completed prior to the initiation of the retrofit project.  The individual
steps shown in Figure *-l* are explained in more detail in Table 6-45.
                             6-88

-------
00
VO
                        FIGURE   6-17    TINE SCHEDULE  FOR  THE  INSTALLATION  OF A WET  SCRUBBER  ON  A  WET-PROCESS
                                                                               PHOSPHORIC  ACID PLANT34
                                                                                                               0., P,
                               n
MILESTONES


      2

      3
      4

      5
ACTIVITIES

Design otion

   A-C
   A-B
   C-0

   D-E

   E-f

   F-G
   G-l
   1-H
Milestones

Activity and durarlan in weeks


 Dare of lubmitlal of final control plan ro appropriate agency •

 Date of award of control device contract.

 Date of Initiation of on-site construction or Installation of emission control equipment.

 Date by which on-iite construction or Installation of emission control equipment Is completed.

 Date by which final compliance is achieved.
                             H-I
                             1-2
                             2-J
                                                                                                                                   ELAPSED TIME (WEEKS)
    Preliminary investigation

    Source tests

    Evaluate control alternatives

    Commit funds for total program

    Prepare preliminary control plan and compliance
    schedule for agency

    Agency review and approval

    Finalize plans and ipecifications

    Procure control device bidi

    Evaluate control device bids

    Award control device contract

    Vendor prepares assembly drawings
Designation
   J-K
   K-L
   L-M
   K-N
   N-0
   0-P
   P-3
   3-M
   M-Q
   Q-4
   4-5
Review and approval of assembly drawings

Vendor prepares fabrication drawings

Fabricate control device

Prepare engineering drawings

Procure construction bids

Evaluate construction bids

Award construction contract

On-site construction

Install control device

Complete construction (system tie-in)

Startup,  shakedown,  preliminary source test

-------
Table
                      DESCRIPTION OF INDIVIDUAL ACTIVITIES INVOLVED IN THE PROCUREMENT, INSTALLATION, AND

                                             STARTUP OF CONTROL EQUIPMENT.35
         ACTIVITY
           CODE
               ACTIVITY
              DESCRIPTION
DETAILS OF ACTIVITY AND ESTIMATED TIME REQUIREMENT
         G-l
              Finalize plans and specification
         1-H
              Procure control device bids
en
i
vo
o
         H-I
              Evaluate control device bids
         1-2
              Award control device contract
The control system is specified in suffient detail for
control equipment suppliers and contractors to prepare
bids.  A final.control plan summarizing this information
is also prepared for submittal to the appropriate aqency.
Two to six weeks are allocated for this activity.  The
variation is dependent on the magnitude and complexity
of the project.

Transmittal of specifications for the control  device and
request for bids from suppliers.
A minimum time of four weeks is required to procure bids
on small jobs.  A maximum of twelve weeks should be allowed
for large non-standard units. Initial vendor quotations
frequently do not match bid specifications, thereby requiring
further contacts with each bidder.

The bids are evaluated and suppliers are selected.
Two to five weeks are required for evaluating control device
bids.  Small, privately owned firms will require little time,
whereas in large corporations, the bid evaluation procedure
often involves several departments thereby increasing the
time requirements.

The successful bidder is notified and a contract is signed.
A minimum of two weeks should be allocated for preparing
the final contract papers and awarding contracts for the
control device and other major components.  This activity
will take longer in large corporations where examination and
approval of the contract by several departments is required.

-------
                   .(continued).  DESCRIPTION OF INDIVIDUAL ACTIVITIES INVOLVED IN THE PROCUREMENT,
                 INSTALLATION, AND STARTUP OF CONTROL EQUIPMENT.
                                                                                     35
        ACTIVITY
         _C_ODE

        2-J
 ACTIVITY
DESCRIPTION
 Vendor prepares shop drawings
VO
        J-K
 Review and  approval of
 assembly drawings
        K-L
Vendor prepares fabrication
drawings
 DETAILS OF  ACTIVITY AND  ESTIMATED TIME  REQUIREMENT
 The vendor prepares the assembly drawings for the
 control device.  For the smaller and more common types of
 control equipment, standard shop drawings which apply to
 XEIL0?11*?1 e^1P"ent size ranges may be used with the
 appropriate dimensions underlined or otherwise indicated
      JISndel!1ce!£ U may be necessary *> Prepare drawings
          ll£ f°rthe Eroject at hand-  Tne drawings are
             H Cl-6nt f°rn hl's approval Pr1or to ^nitrating
 «         " d!;aw:n9S.   Depending on  the complexity and
 originality of the design,  the time  required by the vendor
 to submit assembly drawings could vary from feJ weeks  to
 few months.   Two to six weeks  are estimated for this activity.

The client reviews the assembly drawings and gives approval
to begin fabrication drawings.  The client also uses the
assembly drawings to prepare the necessary engineering drawings
One to two weeks are sufficient for review and approval of   "
assembly drawings.  The longer time is required for any delay
in approval as a result of revisions and modifications'".

Upon receipt of approval from client to proceed with con-
struction of the control device, the vendor prepares fab-
rication or shop drawings which will  be used in the manu-
facturing and assembling of the control equipment.  Three
to eight weeks are normally required for this task.

-------
       Table «*«S(continued).  DESCRIPTION OF INDIVIDUAL ACTIVITIES INVOLVED IN THE PROCUREMENT,

                                     INSTALLATION, AND STARTUP OF CONTROL EQUIPMENT. 35
       ACTIVITY
         CODE
 ACTIVITY
DESCRIPTION
           ACTIVITY AND ESTIMATED TIME REQUIREMENT
                     Prepare engineering drawings
       L-M
01
I
<£>
ro
 Fabrication of Control
 device
This is the time which is required by the client
(or his consultant) to prepare an engineering
drawings package for use by the construction company
for installing foundations, structures, ductwork,
electrical outlets and any other Items not supplied with
the control device.  The drawings will also show the location
and tie-in of the control device.  Estimated engineering ttme
for the project in question is 10 weeks.

On small size control devices which can be shop assembled,
this activity represents the fabrication, assembly, and
delivery of the control unit to the site.  On larqe field
erected control devices, the time shown for this activity
indicates the fabrication and delivery of the first components
to the site.  Delivery of the remaining components continues
throughout the construction phase.  The duration of this
activity should be estimated after consultation with manufac-
turers of the appropriate air pollution control device.  Es-
timate time requirement for this project is  24 weeks.
       N-0
 Procure construction bids
The bid package specifying the scope of work and specifications
of materials and including the drawings are mailed to selected
contractors.  During this period, the contractors prepare their
bids for needed material and labor to install all ductwork,
piping, utilities, and control equipment.  A minimum of four
weeks should be allocated for obtaining bids from the
contractors.

-------
       Table faft(continued).  DESCRIPTION OF INDIVIDUAL ACTIVITIES INVOLVED IN THE PROCUREMENT,

                                     INSTALLATION, AND STARTUP OF CONTROL EQUIPMENT.35
       ACTIVITY      ACTIVITY
         CODE       DESCRIPTION
                                                 DETAILS OF ACTIVITY AND ESTIMATED TIME REQUIREMENT
       0-P
       P-3
              Evaluate construction bids
              Award construction contract
Ot

VO
CO
3-M
On-site construction
       M-Q
              Install  control  device
Construction bids are evaluated and the successful
bidder selected.  Two weeks are estimated for this
activity..

Construction contract is prepared.  In larae corporations,
it is reviewed and approved bv several departments prior
to its submission to the successful contractor.  Two
weeks are allowed for this activity.

This consists of site clearance, pourinq of the foundation,
erecting structural members, ductwork, and installation of
auxiliary equipment.  Twelve weeks were estimated for this
activity.

This activity is essentially an extension of the preceding
construction work.  The time is primarily allocated for
installation of a shop assembled (or modular) control device.
In case of field erected unit, it represents the time which is
required to complete the installation of the remaining com-
ponents as they arrive on site. The installation time for
this case is estimated to be six weeks.

-------
         Table.* & (continued).   DESCRIPTION OF  INDIVIDUAL ACTIVITIES  INVOLVED  IN THE  PROCUREMENT,

                                       INSTALLATION,  AND STARTUP  OF  CONTROL  EQUIPMENT.35
         ACTIVITY
          CODE
 ACTIVITY
DESCRIPTION
         Q-4
 Complete construction
 (system tie-*n)
C7I
I
IO
        4-5
 Start up, shakedown,
 source test
DETAILS OF ACTIVITY AND ESTIMATED TIME REQUIREMENT
Tying the control device into the process requires that
the process be shut down.  This shut down is usually
scheduled so that it will have the least imoact on the
operation.  The contractors responsibility usually ends
at this point when the client and the vendors representative
accept the construction as beina complete.  Two to six weeks
are allocated for tie-in.  In large installations where the
process cannot be conveniently shut down at the end of
construction phase, longer times may be required.

The process is brought back on-line and any unforeseen
problems with the control system are resolved during this
time.  Source testing may be performed to determine if
performance of the system is acceptable.  Depending on the
type of control  device installed, start UD, shake down, and
preliminary source testing would require from two weeks for
small and simple installation to about eiqht weeks for a large
and complicated  system. '

-------
6.7  REFERENCES

1.   Atmospheric Emissions from Wet-Process Phosphoric Acid
     Manufacture.  National Air Pollution Control  Administration.
     Raleigh, North Carolina.   Publication Number  AP-57.   April  1970.
     p. 25-26.

2.   Reference 1, p. 31.

3.   Technical Report:   Phosphate Fertilizer Industry.  In:  Group III
     Background Document.   Environmental  Protection Agency.  Research
     Triangle Park.  p.  -.

4.   Reference 1, p. 30-32, 49, 51-52.

5.   Air Pollution Control Technology and Costs in Seven  Selected
     Areas; Phase I.  Industrial  Gas Cleaning Institute.   Stanford,
     Connect!cuti  EPA Contract 68-02-0289.  March 1973.  p. 52.
6.   Reference 5, p. 41,  43.

7.   Test No. 73-PSA-2;  Texas  Gulf,  Inc.;  Wet Process Phosphoric  Acid;
     Aurora, North Carolina; August  31-September 1, 1972.   Environmental
     Engineering, Inc.   Gainesville, Florida.  Contract No. 68-02-0232.
     p. 4.
8.   Technical Report:   Phosphate Fertilizer Industry.  In:  An
     Investigation of the  Best Systems  of Emission Reduction for Six
     Phosphate Fertilizer  Processes.  Environmental Protection Agency.
     Research Triangle Park, North Carolina.  April 1974.   p.  25.

9.   Reference 3, p. -.
                                     6-95

-------
10.   Guthrie,  K.M.;  Capital  Cost Estimating.  In:  Modern Cost-
      Engineering Techniques,  Popper, H.  (ed).  New York, McGraw-Hill
      Book Co., 1970.  p. 80-108.
11.   Reference 5, 192 p.

12.   Standards and Costs; Gas Absorption-and Pollution Control  Equip-
      ment.  Ceil cote Company.  Berea, Ohio.  Bulletin 1200.  19 p.
13.   Guthrie,  K.  Piping, Pumps, and Valves.  In:  Modern Cost-
      Engineering Techniques,  Popper, H.  (ed).  New York, McGraw-Hill
      Book Co., 1970. p. 161-176.
14.   Reference 5, p. 39.
15.   Reference 5, p. 57.

16.   Goodwin, D.R.  Written communication from Mr. R.D. Smith,
      Occidental Chemical Company.  Houston, Texas.  April 30, 1973.
17.   Reference 5, p. 148.

18.   Test No. 72-CI-25; Royster Company; Diammonium Phosphate;
      Mulberry, Florida; May 17-18, 1972.  Contract No. 68-02-0232.
      p. 8.

19.   Test No.  72-CI-18;  Royster Company; Run-of-Pile  Triple
      Superphosphate; Mulberry, Florida; February  29-March 1,  1972.
      Environmental  Engineering, Inc.   Gainesville, Florida.   Contract
      No. 68-02-0232.  p. 4-5.
                                 6-96

-------
 20.    Reference  3,  p.  -.
 21.    Reference  20,  p. 4-95.

22.    Reference  5,  p.  114.

23.    Control Techniques  for  Fluoride  Emissions.   Environmental  Health
       Service.   Second Draft,  September  1970.  p. 4-95  (unpublished).
 24.    Reference  3, p.  -.
 25.   Chatfield,  H.E. and R.M. Ingels.   Gas Absorption Equipment.  In:
      Air Pollution Engineering Manual, Daniel son, J.A. (ed).  Research
      Triangle Park, Ncrth Carolina.  Environmental Protection Agency.
      1973.  p.  229.
 26.   Reference  5, p. 80.
 27.   Reference  1, p. 26.
 28.   Reference 3, p. -.

29.   Reference  25, p. 228.
30.   Emmert,  R.E. and R.L.  Pigford, Gas  Absorption  and  Solvent
      Extraction.  In:   Chemical  Engineers'  Handbook, Perry,  R.H.,
      C.H.  Chilton,  and S.D.  Kirkpatrick (ed).  New York.   McGraw-
      Hill, Inc.  1963.  p.  14-37 to 14-39.
31.   Reference 1, p.  27.
32.   Reference 3, p.  -.
                             6-97

-------
33.  Reference 1, p. 27.

34.  Technical Guide for Review and Evaluation of Compliance
     Schedules for Air Pollution Sources.  The Research Triangle
     Institute and PEDCo - Environmental Specialists, Inc.  Pre-
     liminary Draft.  June 1973.  p. 3-39.  (unpublished).
35.  Reference 34, p. 2-4 to 2-8.

-------
                 7.  ECONOMIC IMPACT
7.1   INTRODUCTION
      This section describes the economic impact of adopting regulations
that  require control of fluoride emissions from existing wet-process
phosphoric acid, superphosphoric acid, diammonium phosphate, run-of-pile
triple superphosphate, and granular triple superphosphate facilities.
The costs shown in Table 7-1 are based upon the installation and
operation of control equipment described in chapter 6.1.3.  Installation
of other, less efficient control equipment is not expected to result
in any significant reduction in the economic impact incurred.  The
capital costs and annualized costs of installing control equipment
represent expenditures needed to achieve the emission guidelines shown
in Table 1-1, but would also apply to the adoption of less stringent
fluoride emission regulations.
     The economic impacts have been developed on a nrocess-by-process
basis since the national or industry-wide impact will be dependent
upon the collective actions of the states.  To provide a perspective
on the significance of the costs incurred by adopting fluoride
emission regulations, they are related to unit production and product
sales price (Table 7-1).  Additional insight on potential impacts
related to costs are given by a discussion on potential  plant closures.
Criteria are presented that describe circumstances that could result
in plant closures, and the number of closures within the industry
that would result if all states adopted fluoride emission regulations
is estimated.
     The information presented in this chapter is intended to assist
states in deciding on the advisability of adopting fluoride regulations.
                              7-1

-------
 It is not expected that these emission guidelines would be
 appropriate for all existing facilities.
 7.2  IMPACT ON MODEL PLANTS
      The total capital investment and annualized control cost ob-
 tained from section 6.1.3.1 for each of the model facilities is
 presented in Table 7-'l on a plant basis, on a unit product basis, and
 as a percentage of the product sales price.  For purposes of this
 analysis, it is assumed that the wet-process acid plant sells all
 acid production at prevailing merchant acid prices.  The estimated
 control  costs for superphosphoric acid, diammonium phosphate, and
 triple superphosphate plants reflect the retrofit requirements of
 both the individual production facility and an associated wet-process
 acid plant which produces the required intermediate phosphoric acid.
 The captive acid plants are assumed to be sufficiently sized to
 supply the needs of the various production units.  For example, the
 SPA plant is associated with a 300 ton P205/day acid  plant while  the
 DAP plant requires  a 500 ton/day unit.   Control  costs  for the captive
 units were  obtained by prorating the cost developed for  the model  acid
 plant.
     A more  detailed  analysis  of the potential  financial  effects  of
 control  costs  upon  the phosphate industry could  be  obtained by  cal-
 culating  the changes  in  profits  and  cash  incomes  for all  plants or
 firms in  the industry  if the necessary information were available.
 Diammonium phosphate and granular  triple  superphosphate are the more
 popular products sold  and their  processing will  incur the higher
 control costs on a unit basis.   Industry  statistics, representative
of 1973 performance, Indicate that after-tax profit margins ranged
                               7-2

-------
                                             TABLE 7-1
     SUMMARY OF RETROFIT CONTROL COST REQUIREMENTS FOR VARIOUS PHOSPHATE FERTILIZER MANUFACTURING PROCESSES
End Product
Design Rate, TPD
(P205 Basis)
Control Capital, $
Sales Price
($ per ton
product)
Annual i zed Costs
a. Total , $
b. Unit Basis
($ per ton
product)
c. As a % of
Sales Price
Phosphoric
Acid
500
208,000-
249,000
105

57,000-
69,000
0.19 -
0.23
0.2
Super-
Phosphoric
Acid
300
240,000
152

65,000
0.48
0.3
DAP
500
887,000
145

242 ,000
0.68
0.5
ROP-TSP-
(Case A)
550
875,000
126

262,000
0.66
0.5
ROP-TSP
(Case B)
550
1,465,000
126

404,000
1.03
1.0
GTSP
400
1,234,000
130

339,000
1.18
0.9
CO
      Source  of  Price  Quotations  -  Chemical Marketing Reporter, November 4, 1974.

-------
 from 5 to 6 percent of sales and approximately doubled these per-
 centages in 1974.  Against  this level of profitability, control costs
 as shown in Table  7-1 appear to have minimal impact on a plant typical
 of this profit performance.  As long as product prices are unrestricted
 (the Cost of Living Council removed price ceilings on domestic ferti-
 lizers on October  25, 1973) and plant utilization remains at the cur-
 rent level of approximately 90 percent, control costs could be ab-
 sorbed by the industry without any price increases.   On the other hand,
 price increases to pay for the costs would be minimal.
      An objective of this analysis is to highlight where the implemen-
 tation of the emission guidelines  might impose an economic
 burden upon plants.  A scenario for possible plant closures could be
 presented in this fashion:  overcapacity in spite of growing demand
 develops in a particular segment of the industry resulting  in under-
 utilization  at  rates  near 75 and 80 percent of capacity.  Prices
 and profits  subsequently  decline.   In such  a situation, plants
 would  probably  close;  however,  the  question  is  to what extent would
 the impact of retrofit controls  be  responsible  for plant closures.
 In section 7.3, criteria  are presented which can be used to pinpoint
 the extent of plant closures.
 7.3  CRITERIA FOR PLANT CLOSURES
     Reasons for closing  a facility are usually traced to the absence
of profitability for a specific site or facility.  Managers of existing
plants faced with increased capital requirements for continuity of
operations will nave to decide whether the incremental investment will
"save" future cash  income that otherwise would be lost by ceasing
operations.  Plant managers will have the following options in such a
                             7-4

-------
      1.  Undergo Increased capital expenditures on the existing plant.
      2.  Shut down the plant and discontinue business.
      3.  Shut down the plant and replace it with a new plant.
 The  selection of an option is based on an interest or opportunity
 cost for employing the required capital.  There is usually a minimum
 return that a plant manager will accept for employing funds—interest
 cost for borrowing money or the interest cost of investing in short
 term obligations.  Since there is a risk with employment of capital,
 businesses will require a higher rate of return for investing of
 funds.  A familiar tool for analyzing investments involves the deter-
mination of the >um of all  future  cash  flow (income)  streams  over a
projected time span discounted (with  the  appropriate  interest rate) to
the present.   If the sum of these  discounted residuals exceeds intended
cash outlay for investment,  resulting  in  a  positive  term for  net
present value, than the investment will  be  a good  choice.   Conversely,
if the discounted present value  of projected cash  flow streams results
in a negative value, then the  proposed  investment  will be rejected.
     The managerial tool  of discounted  cash flow analysis can be
applied to the retrofitting of control  equipment to  existing  plants
in this manner.   If the existing operations can only  be continued in
the future by meeting a standard,  then  the  investing  of the control
capital has to be evaluated on the basis  of the value of the  future
income derived from continuing the operation of the  present plant.
The merit of continuing operations after retrofitting a plant must be
evaluated in retrospect with the alternatives of discontinuing operations
and building a new plant.
                             7-5

-------
     Guidelines for pinpointing plants as candidates for closure  are
presented as follows.  First, new plants to replace existing  plants
of the comparable model size described in Table 7-1 v/ould require some
$10 to $20 million.  In no instance could the construction of a new
plant be a better alternative than retrofitting controls requiring
the magnitude of capital, or even twice the values, shown in  Table  7-1.
On the other hand, plants that  have small or negative cash incomes
prior to retrofitting would certainly close.  Plants that have small  or
negative profits  (after deducting depreciation charges) would eventually
become candidates for closure upon termination of their depreciation
schedules and subsequent increased tax liability.
     The type of plants that would most likely face these circum-
stances are the following:
     1.  Small plants which generally suffer from the usual economies
         of scale of production—less than 170,000 tons-per-year  cap-
         acity.1
     2.  Old plants which generally have outlived their useful or
         economic lives—twenty years or more.
     3.  Plants isolated from raw materials—particularly diammonium
         phosphate plants that  purchase merchant phosphoric acid and
         ammoni a.
     4.  Plants likely to suffer from  a  shift  in the overall  market
         structure  as  a  result  of external  forces.
      Financial data  on an  individual  plant  basis necessary to evaluate
the  impact  of  retrofit controls are  unfortunately unavailable.  Hence,
plant  closures  can  De estimated only  from  a categorical  approach, which
                                  7-6

-------
classifies plants that possess characteristics of the nature  of those
discussed above.   Any estimate of plant closures has  to  be presented
with the usual qualifications.
7.4  IMPACT ON THE INDUSTRY
     At the present time, the condition of the fertilizer industry is
healthy.  Prices  and profits in 1974 were the highest they have been
in years.  The U.S. industry has become a leader in phosphate processing
technology and benefits from world trade in both rock and concentrated
phosphates.  This position became more pronounced recently, in spite
of the fracture in the international monetary structure  and con-
current high inflation.  When the Cost of Living Council  lifted
price ceilings on October 25, 1973, domestic prices heretofore con-
strained by CLC immediately arose 60 percent on the average reflecting
the foreign demand for domestic phosphate products.  Demand for
fertilizers to increase agricultural production and yields has been
strong and will continue to be so, in spite of fluctuating international
currency values.   Projected long-term demand for phosphate nutrients
                                                     2
is expected to grow a't an annual rate of 5-6 percent.
     Historically, the fertilizer industry has experienced cyclic
patterns of overexpansion followed by plant shutdowns and product price
cutting.  New phosphoric acid plant expansion scheduled to come on
stream  in  1975-1976 may result  in short term price declines until in-
creases  in consumer demand  restores equilibrium with capacitv.  In
anticipation of overexpansion,  producers will probably curtail  con-
struction  activity in  the period  beginning  in 1976-1977.   However,
during  this slack period, retrofitting of existing plants  for
                            7-7

-------
controls will  be required in accordance with  implementation plans.
Therefore,  these retrofit projects should  not hinder new construction.
Rather  than resulting in  plant closures, requirements for retro-
fitting fluoride emission control  systsms  will probably encourage some
improvements of  marginal  plants.
      The nature of the impact of the lll(d) regulations  for the
 fertilizer industry will  be geographical in scope.   The  state of
 Florida, where most of the industry is located,  has adopted regula-
 tions for the existing industry that are equivalent m most instances
to  the  emission  guidelines.   Most  of the remainina  states with phos-
 phate process  facilities  have no emission  standards.
      The greatest control cost - on a unit basis  -  for any  process
subject to  standards is for the combination of processing anc storage
of  granular triple superphosphate.   However,  75 percent of  the industry
capability  in  GTSP production will  be required to meet the
emission  guideline by July 1975 regardless  of Federal action.
a large portion  of the production  facilities  will not require additional
retrofit  controls, the impact upon  the  industry doesn't appear severe.
For run-of-pile  triple superphosphate,  the  conclusion would be similar
to the  GTSP as some  60 percent of  the industry will be adequately con-
trolled  because  Of state  standards.
     The one segment  of the  industry where a wide-scale effort in
retrofitting would be  required  is for diammoniu"! phosphate plants.
Some 60 percent of industry  cdunilty «ould be exnected to retrofit  as  a
result of Federal  regulations.  Control costs for this orocess,
                               7-8

-------
  however,  would  amount  to  only  0.5  percent of  sales.  These costs alone
  are  not sufficient  to  close any plants.
       Diammonium phosphate plants which incur water abatement costs as
  great or  greater than  fluoride emission control costs would be likely
  candidates for  plant closures.3  There is no specific information
  concerning plants which may fall  into this  category.   The only
  definitive statement that can  be  made is  that those affected  will
  be outside the state of Florida and may amount to  3 to  5
  plants,  or approximately 10 percent of the  total  DAP  manufacturing
 capacity.
      With  regard to  triple superphosphate plants,  1 to  3  plants  (out-
 side Florida)  may close as a result of implementing the recommended emission
 guidelines for control  of aaseous  flutHHp.  This  is  likely to occur
 in a  geographical region where  there is an oversupply of  phosphate
 processing capacity.  An abundant  supply of  low-cost  sulfuric acid
 derived from non-ferrous smelters  in the Rocky  Mountains  area could be
 an incentive for construction of new phosphate  facilities, ultimately
 resulting  in oversupply and price-cutting.   Triple superphosphate capacity
 does  appear to be expanding rapidly  in this  area with a new 340,000
 ton-per-year plant coming on-stream  in 1975-1976.
      Most  of the control costs associated with  a TSP complex are for
 the solids manufacture  and storage.  Therefore, the closure of a TSP
 facility as implied above does not mean that the entire complex
 will  be shut down.  The  plant manager has several options—(1) sell
 merchant add, (2) convert to mixed fertilizers, or (3) produce
 diammonium phosphate.  However, if the same plant manager is  faced
with  Installing water abatement facilities,  the overall  abatement costs
will affect the entire facility.
                              7-9

-------
7.5  IMPACT ON EMPLOYMENT AND COMMUNITIES
     The fertilizer industry is generally recognized as a capital
intensive industry; in other words, labor requirements for production
work and plant supervision are small, relative to plant sales.
Usually, those plants that may be affected by implementation of the
emission guidelines are widely dispersed throughout the
United States.  Only in central Florida does the fertilizer industry
represent a substantial portion of overall community economic activity
and employment.
     For purposes of illustrating the effects of plant closures on
employment, the shutdown of 1 to 3 triple superphosphate plants cited
in Section 7.4 might result in the loss of 10 to 50 jobs.   Only those
jobs directly associated with the triple superphosphate plants would
be affected.  Employment in supporting activities such as rock mining,
phosphoric acid production, and transportation services would remain
unaffected.
7.6  SUMMARY
     An optimistic outlook for the phosphate fertilizer industry in
the next few years has been presented, but such an appraisal must be
cautionary after reviewing the historical chronic cyclic patterns
of product shortages and oversupply.  Assuming that oversupply con-
ditions may occur in the next few years, some estimates of plant
closures have been made.  In the triple superphosphate sector of
the industry, as many as three plants could close as a direct result
of the states adopting the emission guidelines.  In the diammonium phosphate
a combination of e/penditures for retrofitting both fluoride emission
                             7-10

-------
controls and water effluenv: controls may result in as many as five
plant closures, or 10 percent of industry capacity.
     However, fluoride emission controls alone would not cause these
closures.  Associated costs for fluoride emission controls for wet-
process phosphoric acid plants that do not have attendant DAP or TSP
processes will not warrant plant closures.  Similarly, costs for
superphosphoric acid plants do not present any apparent problems.
     The number of predicted closures reflects the adoption of the
emission guidelines by all states; therefore, it reflects the maximum
number of closures that may occur.
                            7-11

-------
7.7  REFERENCES
1.   David, Milton L., J.M. Malk, and C.C. Jones.  Economic Analysis
     of Proposed Effluent Guidelines for the Fertilizer Industry.
     Development Planning and Research Associates, Inc.  Washington,
     D.C.  Publication Number EPA 230-1-73-010.  November 1973.
     p. VI-12 to VI-15.

2.   U.S. Industrial Outlook 1972 - With Projections  to 1980.  U.S.
     Department of Commerce.  Washington, D.C.  Publication Number
     BOC-704-08-72-005.  p. 174-175.

3.   Reference 4, p. V-13 to V-18.

4.   Reference 4, p. VI-26.
                           7-12

-------
            8.  EMISSION GUIDELINES FOR EXISTING
                PHOSPHATE FERTILIZER PLANTS
8.1  GENERAL RATIONALE
     These emission guidelines represent the same degree of control
as is required by the standards of performance promulgated for new
plants [wet-process phosphoric acid, superphosphoric acid, diammonium
phosphate, run-of-pile triple superphosphate (production and storage),
and granular triple superphosphate (production and storage)].  The
emission guidelines were developed after consideration of the
following factors:
     1.  The degree of emission reduction achievable through the
         application of the best adequately demonstrated svstem of
         emission reduction (considering cost).
     2.  The technical and economic feasibility of applying the
         best demonstrated technology to existing sources.
     3.  The impact of adopting the emission guidelines on annual
         U. S.  fluoride emissions.
     4.  The environmental, energy and economic costs of the
         emission guidelines.
     Identification of the best demonstrated control technology was
accomplished first.  During the development of standards of
performance for new facilities in the phosphate fertilizer industry,
the spray-crossflow packed bed scrubber was found to represent the
best demonstrated control  for total fluoride emissions.  Historically,
the spray-crossflow packed bed scrubber was developed to control
fluoride emissions from the phosphate fertilizer industry.  From this
                              8-1

-------
viewpoint,  it  is  not  unusual  that  this  scrubber design is the best
demonstrated control  technology.   Many  of the  spray-crossflow packed
bed scrubbers  tested  by  EPA were retrofitted.  For this reason,
spray-crossflow packed bed scrubbers are recognized as the best
demonstrated control  technology for both new and existing plants.
     Alternative  fluoride control  technologies, such as the venturi
and cyclonic spray  tower scrubbers, can only provide approximately
two transfer units  for fluoride absorption  unless two or more are used
in series,  at  multiplied costs.  Spray-crossflow packed bed scrubbers
are not  limited by  the number of transfer units which they can provide;
in practice, five to  nine transfer units per scrubber are provided.  Con-
trol of  gas streams with high particulate loadings has caused a plugging
problem  for spray-crossflow packed bed  scrubbers in the past.  However,
use of a built-in venturi  scrubber and  other improvements in spray-
crossflow packed  bed  scrubber design have eliminated this problem.  In
addition, all  current fluoride control  technologies involve some type of
scrubbing system, and consequently, they share any plugging tendencies,
as well  as  similar  costs and  energy requirements.  With these considera-
tions in mind, it is  not unreasonable to base  fluoride emission guide-
lines on the one  clearly superior  scrubbing technology.
     Evaluation of  the problems and costs associated with a retrofit
project  is  complicated by the lack of actual data.  Some of the
facilities equipped with spray-crossflow packed bed scrubbers  installed

                              8-2

-------
 the units  as  part of the  original  plant  design.   Retrofit  information
 that is-available is usually  incomplete  because  of  changes  in  plant
 management and lack  of cost breakdowns.   Retrofit models were  therefore
 developed  to  evaluate the technical  and  economic feasibility of  in-
 stalling  spray-crossflow  packed  bed  scrubbers  on existing  WPPA,  SPA,
 DAP, ROP-TSP, GTSP processing, and GTSP  storage  facilities.  The retro-
 fit model  approach was meant  to  estimate costs for"an" average"plant and
 to clarify the technical  problems  involved  in  a  typical retrofit pro-
 ject.   No  technical  problems, other  than space limitations, were
 foreseen  for  the  average  plant. • In  all  cases, the  mannitude of  the
 estimated  retrofit costs  are  minimal as  is  discussed  in Section  7.
      Table 9-1  indicates  the  impact  of the  emission ouidelinei.
 on annual  U.S.  fluoride emissions.   Adoption of  the emission guidelines
 would result  in emission  reductions  ranging from 50 percent for  fiTSP
 storage facilities to 90  percent for ROP-TSP plants.  Overall emissions
 from the affected  facilities would be renuced  by 75 percent.
      Environmental and  energy costs  associated with the
 emission guidelines  are minimal.  With current spray-crossflow packed
 bed  scrubber  designs, gypsum  pond water  can be used as the scrubbing
medium to meet the emission guidelines in practically all  cases.
 In the rare case where the partial pressure of fluoride out of pond water
 is high, the emission guidelines can still be met.  The aliquot of water
 sent to the final   section of scrubber packing nay be fresh or limed water.
                                             *
This aliquot will  only be a small fraction of  the total water to the scrubber
                              8-3

-------
and will contain only a small fraction of the total fluoride absorbed
in the scrubber.  This implies  that no additional effluent need be
created.  Any solids generated  by fluoride scrubbing (e.g., in the WPPA
process) would go to the gypsum pond and cause no more than a 0.06
percent increase in the amount  of solids normally produced.
     The estimated total annual incremental electrical energy demand
which would be created by  fluoride control to meet the
emission guidelines is only  26.9 X 106 KWH/yr.  This is equivalent
to the amount of energy required to operate only one 300 tons/day
P205 SPA plant by the submerged combustion process 115 days/yr.

8.2  EVALUATION OF INDIVIDUAL EMISSION GUIDELINES

8.2.1  Wet-Process Phosphoric Acid Plants
Fluoride Emission Guideline
0.01 grams of fluoride  (as F~)  per kilogram of P,,0fi input to the
process.
Discussion
     The emission guideline  is  equal to the promulaated
SPNSS.  It is estimated  that each will require removal of  99 percent
of the  fluorides evolved  from the wet-acid process.  A sprav-crossflow
packed  bed scrubber  is  capable  of providing this  collection efficiency.
                               8-4

-------
Rationale
1.  The economic impact of the emission Guideline on the
industry should be negligible.  Approximately 53 percent of the
existing wet process acid plants, ^ccountin^ for 7f- percent of the
production capacity, *ro either sufficiently controlled at present
to meet an emission level of 0.01 grans F/kilogram PgOs or will be
required to attain that level of control regardless of the proposed
emission guideline.  This estimate is based on the assumption that
all wet-process acid plants built since 1967 have installed controls
capable of meeting an emission level of 0.01 grams of fluoride
par Lilograrc P^Oj, input as pare of t!i«2 original plant Jasign.
     I'he  retrofit costs for those plants  that are affected, approximately
 $230,000  for a 500 ton P205/day facility, can be successfully absorbed
 within the  existing cost structure.   Annualized control  costs for an
 average sized plant,  including capital  charges, amount to approximately
 0.2  percent of sales.

 2.   Relaxation of the  guideline to allow emission increases of 50 to
 100  percent would not alto* .additional  control options or appreciably
 reduce retrofit costs  for the following reasons:
      a.   Only a packed bed scrubber is  capable of providing the  re-
          quired fluoride removal  efficiency = 99 percent.   A tenfold
          increase in  the emission guideline would be required
                              8-5

-------
         to allow the use of other commonly used  scrubber designs -
         Venturis, cyclonic spray towers, etc.  with Gr)-rn percent
         collection efficiency.

     b.   Packed bed scrubber cost will not vary significantly  with
         moderate changes in packing depth.  The cost of additional
         packing to increase scrubber efficiency is minor compared
         to overall control costs.
3.  Estimated impact of  the emission guideline on annufl
fluoride emissions is significant - 73 percent reaction.

8.2.2  Superphosphoric Acid Plants
Fluoride Emission Guideline
 0.005 grams of fluoride per kilogram of P20g input to the
 nrncfiss.
Discussion
     The emission guideline for  existing SPA olants is equal
to  the promulgated SPNSS.   Compliance with this  emission guideline
would require  removal of. nnnrnyiaafrrly 90 percaot of  thee-ftuarrdes
now being  emitted from SPA plants  using the submerged  combustion process.
A spray-crossflow packed bed scrubber should be  capable of  providing
 this performance.  Three designers of control  equipment have  submitted
proposals  to one operator for control to the level of the emission
guideline; venturi  and  other designs using the vacuum evaporation
process  (79 percent of the SPA industry) will  reouire no aJditional
control.
                             8-6

-------
 Rationale
 1.  Impact on the industry snoulu be negligible.  The two existino olants
 using  the  submerged combustion process could be required to adc1 retrofit
 controls.
 2.   Existing submerged  combustion  plants  should be  capable  of meeting
 tlie emission guideline  by treating  the exhaust  stream from
 controls with a  spray-crossflow  packed bed  scrubber.  This  scrubber  can
 be  acded to  any  existing mist  separators, baffles,  and  spray  chambers,
 as  was assumed in the SPA retrofit  model, Figure  6-5.

 3.  Retrofit costs are  expected  to  be acceptable  -  $103,000 for a  300
 ton per day  plant.  Annualized control costs, including  capital charges,
 amount to  only 0.3 percent of sales.

 4.  Relaxing the emission guideline to allow a  three-fold increase in
 emissions  (0.015 grams  F/kilograms  PpOc) would  be required  to
accommodate  the use of Venturis anH cyclonic snra*/ t.owprs, if t.hp rph.ro-
 fit costs  are to remain about the same.
 8.2.3   Diammonium Phosphate Plants
 Fluoride Emission Guideline
 0.03 grams of fluoride  (as F~) per  kilogram of  P205 input to the process,
Discussion
     The emission Guideline for existing DAP plants is equal to the
promulgated  SPNSS.   Compliance would require removal of approximately
85 percent  of the fluorides  evolved from the DAP process.  Snray-crossflow
packed bed  scrubbers,  added  to any existing Venturis,  are capable  of
                              8-7

-------
providing the required collection efficiency.  As pointed out in
section 8.1, new designs for these scrubbers are available and are
expected to overcome problems  formerly associated with pluqqing by
excessive particulates  (2).
Rationale
1.  Relaxing the emission guideline to allow the use of alternative
scrubber technologies would increase fluoride emissions to the
atmosphere by 49 tons per year,  a 50 percent increase.
2.  Retrofit costs - $660,000  for a 500 ton P205/day plant - are not
considered excessive.  Annualized cost, including capital charges,
would amount to 0.37 percent of  sales.

3.  Impact of applying  the emission guideline on fluoride emissions
from U. S. DAP plants is significant - a 75 percent reduction (160
tons/yr).
8.2.4  Run-of-Pile Triple Superphosphate Production and Storage Facilities

Fluoride Emission Guideline
0.1 gram of fluoride  (as F") per kilogram  of PgOg input to the
process.
Discussion
     The  emission guideline is equal  to  the  promulgated SPNSS.  Only
40  percent  of the industry is directly affected  by  the emission
guideline.

                               8-8

-------
      Compliance with an 0.1  aram F/kilonran P?Cr> mission  level  would
 recuire collection of about 99.2 percent of the fluorides evolved
 from the process.  This efficiency can be obtained by a two stage
 system using Venturis and a soray-crossflow packed bee' scrubber.
 Rationale
 1.  Economic impact on the industry should be moderate.  Only 40 oercent
 of the industry is directly affected by the emission  aiiidPlinP.
 The remaining 60 percent will  be required to neet more stringent State
1 regulations.
 2.  No additional control  options would be  made  availabl"  hy  relaxinr
 the emission guideline by 50 to 100 percent.   It would be  necessary to
 triple the emission guideline  to allow the use of a venturi or cyclonic
 spray tower as  the secondary scrubber.

 3.  Retrofit costs -  $725,000  for a typical 550 ton P^/day  plant to
 $1,240,000 for  the extreme  case - are  not considered  excessive.   Annual-
 ized control  costs, including  caoital  charges, amount to 0.40 to 0.70
      A
 percent of sales.   Although  these costs are more severe than  retrofit
 costs  for  most  other  sources,  they  are  expected  to be manageable.

4.   The emission guideline would reduce annual fluoride
emissions from existing ROP-TSP plants by 90 percent.
8.2.5  Granular Triple Superphosphate Production Facilities
 Fluoride Emission  Guideline
 0.1 qram  fluoride (as F")  per  kilooram of P205 input  to the process.
                                8-9

-------
Discussion
     The fluori:1e emission  cjui-Jelino  is  equal to  the nrori:ln?tpd
L^P.'SS.  Conpliance with  the emission  ouic-'eline voulc- r^nuire
collection of about 99.6 percent  of the-  fluoride  evolve:!
from the GTSP production process.  This  efficiency can be obtainecj by
a two-stage system consisting  of  a venturi and a  spray-crossflow
packed bed scrubber.
Rationale
1.  Economic impact of the  emission guideline should he moderate.  Only
25 percent of tr.e industry  is  directly affected by the
emission guideline.  The remaining 75 percent will be required to meet
more stringent State regulations.
2.  Relaxing the emission guideline by 50 percent would provide greater
flexibility with regard  to  the development of a control strategy,
however, it would also allow the  emission of an additional 66 tons of
fluoride per year.  A five-fold increase in the omission nuideline would
be necessary to allow the use  of  a venturi or a cyclonic spray tower
as the secondary scrubber in all  effluent streams.
3.  The estimated retrofit  costs  - $600,000 for a 400 ton P205/day
plant - are not considered  excessive.  Annualized control costs amount
to 0.44 percent of sales.
4.  Tne emission guideline  would  reduce  annual fluoride
emissions from GTSP production facilities by 51 percent.
                              8-10

-------
8.2.6  Granular Triple Superphosphate Storage Facilities
Fluoride Emission Guideline
2.5 X 10"4 gram fluoride (as F") per hour per kilogram of P205 in
storage.
Discussion
     The fluoride emission guideline for existinq granular triple
superphosphate storage facilities is equal to the SPNSS.  In order
to meet this emission level, a typical facility would be required to
remove approximately 90 percent of the fluorides evolved.  Only 25
to 35 percent of the industry currently has this degree of control.
Twenty-five percent of the existing facilities are presently uncon-
trolled.
Rationale
1.   It is estimated that 50 percent of the industry would still be
required to add retrofit scrubbers even if the allowable emissions
were increased by 50 percent.
2.  The cost of retrofitting uncontrolled facilities would not vary
significantly with moderate (50 percent) relaxation of  the emission
guideline.  The major portion of the  costs is associated with
refurbishing the building and is exclusive of the control device
itself.
                              8-11

-------
3.  Retrofit costs for uncontrolled facilities - $540,000 for a 25,000
ton storage building - are not considered to be excessive.  Such a
facility would accompany a 400 ton PgOg/day GTSP production facility.
Annualized control costs, including capital charges, would equal 0.4
percent of sales.

4-  The emission guideline wouUi  reduce annual fluoride
emissions from GTSP storage facilities by 50 percent.
                            8-12

-------
8.3  REFERENCES

1.  Atwood, W.  W., Occidental  Chemical  Company  to  Goodwin,  D.  dated
    June 27, 1973.  Fluorine Emissions  from  Submerged  Combustion
    Evaporation of Phosphoric Acid.

2.  Crane, George B.   Private communication  with Teller Environmental
    Systems, Inc.  New York, N.Y.  December  13, 1974.
                            8-13

-------
                    9.  ENVIRONMENTAL ASSESSMENT
  9.1  ENVIRONMENTAL ASSESSMENT OF THE EMISSION GUIDELINES
  9.1.1  Air
      Installation of retrofit controls similar to those described
  in section 6.1.3.1 could reduce fluoride emissions from existing sources
  by the amounts indicated in Table 9-1.   Emission reductions range
  from 50 percent for granular triple superphosphate storage facilities
  to 90 percent for run-of-pile triple superphosphate plants.  All  estimates
 are based on information  presented  in chapters  3,  5,  and  6 of this study.
      The following procedure was  used to arrive  at the  estimates  listed
 in Tables 9-1  and 9-2.  The percentage  of existing facilities Cor capacity)
 attaining emission levels equivalent to SPMSS was  estimated in  Chapter 5.
 The remainder  of  the existing facilities  were assumed to  emit at  a  rate
 midway  between the SPNSS level and a  level characteristic  of  a  poorly
 controlled plant.   The retrofit models  were used as a source  of
 information regarding poorly controlled plants.
     Total emissions following the installation of retrofit controls
were estimated by applying the SPNSS level to the entire industry
which is  identical to the lll(d) emission guidelines  contained  herein.
All estimates assume a 90 percent utilization of production capacity.
    This general approach was altered in certain instances  (SPA, DAP,
GTSP storage) either to make use of additional  information or to com-
pensate  for the lack of necessary data.
                              9-1

-------
Table 9-1,  ANNUAL U.S.  FLUORIDE  EMISSION REDUCTION DUE TO INSTALLATION
OF  RETROFIT COMTW&S OSRABlT OF MEETING EMISSION GUIDELINES
Segment of Industry
WPPA
SPA
DAP
ROP-TSP
GTSP
Production
Storage
Overall
Estimated 1974
Emissions (Tons F/Yr)
217
12.6
385
662
268
HO
1,685
Estimated Emissions Following
Installation of Retrofit Con-
trols (Tons F/Yr)
58
2.9
97
71
131
70
430
Fluoride Emission
Reduction
(% 1974 level)
73
77
75
90
51
5JL
74.5

-------
Table 9*8.  TYPICAL 1974 FLUORIDE EMISSIONS SOURCE STRENGTHS BEFORE AND AFTER INSTALLATION OF
                RETROFIT EONTWESTCAPABLE OF MEETING'EMISSION GUIDELINES
Type of Plant
WPPA
SPA
(Submerged combustion
f* process)
UJ
DAP
ROP-TSP
GTSP
Production
Storage
Capaci ty
(Tons/Day P20g)
500
300
500
550
400
25,000*
Emissions Before Retrofit
(Lb F/hr)
48.4
3.9
6.86
571
122.6
13.2
Emissions After Retrofit
(Lb F/hr)
.42
.12
1.25
4.6
3.34
1.25
 *Tohs GTSP Stored

-------
     As  indicated  in  Table 9-1,  an  overall  fluoride emission reduction of nearly
 75  percent  can  be  achieved by installation  of retrofit controls capable of
meeting  the emission  guidelines.  The corresponding reduction in
 typical  fluoride emission source strengths  is illustrated by Table 9-2.
 9.1.1.1  Atmospheric  Dispersion  of  Fluoride Emissions
     A dispersion  analysis was made to  compare qround-level  fluoride
 concentrations  downwind  of a  phosphate  fertilizer complex, before and
 after retrofit  of  controls.   The diffusion  estimates were based on 30-
 day average fluoride  concentrations and extended to distances from the
 plant where fluoride  concentrations were less than 0.5 yg/m3.  A 30-
 day average ground-level fluoride concentration of 0.5 yg/m  causes  an
 accumulation of more  than  40  ppm fluoride in  cattle forage, and this
 concentration in their feed is a damage threshold for cattle.
     The fertilizer complex being investigated represents no actual  plant,
 but contains all of the  units discussed in  Section 6.1.3.1 - Retrofit
Models - except the submerged combustion-superphosphoric acid plant.
Emissions from  this complex are  not necessarily typical of the emissions
used in the retrofit  models of section  6, nor are they the same as the un-
controlled source  strengths listed  in Table 9-2.  However, these emis-
sions fall  within the range of  emissions from actual  plants.  Specific
                               9-4

-------
Table 9-3.   EXISTING CONTROLS AND EMISSIONS
  FOR MODEL PHOSPHATE FERTILIZER COMPLEX
1C
1
tn
Product : Items
•Controlled
Gas Flow,
SCFM
KPPA Idigester, filter, ' 21,500
iflash cooler seal
:tank, evaporator !
•hotwell
DAP jreactor-granulator,
idrier, cooler-
, screen
TSP Icone mixer, den,
'storage bldg
GTSP |
'
1
i
j reactor-granu-
' lator, drier,
cooler-screen
1
110,000 i
1
182,000
75,000 from
uncontrolled
storage bide
112,000
i
Fluoride,
IL-s/hr
10.8
3.3
36.5
13.2
22.6

height,
i ft.
60
i
! 85
1
i
t
i 60
i
j bldg.
i louvers
' (a 45 ft
1 85
Stack
teir.o. , aas velocity
°F ft/sec
100 30
i
100 1 30
i
i
i
90 ! 30
1
85 i -
I
i
!
90 ' 30
i '
!
i

-------
                                 Table 9-4.    RETROFIT  CONTROLS AND  EMISSIONS
                                   FOR MODEL PHOSPHATE  FERTILIZER  COMPLEX
Product

WPPA
DAP
TSP
GTSP

Items 1
Controlled
Table 9-3",
plus filtrate
sump and seal
tank, plus
acid storage
same as Table
9-3
same as Table
9-3
storage build-
ing
same as
Table 9-3
Gas Flow,
SCFM
25,000
96,000
182,000
76,000
111,000
Fluoride,
Ibs/hr
0.42
1.25
6.20
2.00
3.34

height,
ft
85
85
70
i — i
70
85
i
Stack
temperature,
or
100
100
r 	 '
90
85
90

qas velocity
ft/sec
40
30
30
40
! 40
!
i
CTi

-------
 fertilizer manufacturing  units  are  pictured  in  Figures 6.3, 6.4,  and
 elsewhere.  All  of these  units  were assembled to  scale on a olot  plan
 of the entire  complex.  From  this plot plan  the  meteorologist could
 measure the distance  relationships  of sources and of interferences such
 as buildings and phosphate  rock piles.  The  heights of these inter-
 ferences were  also tabulated.  Additional information used is shown in
 Tables 9-3 and 9-4.   The  former table indicates emissions from the
 fertilizer complex having existing mediocre  emission controls.  The
 latter table shows the emissions from the same sources after installation
 of good controls.
     The source  data  indicated that aerodynamic downwash was a problem
 at the facility  modeled, particularly for wind speeds in excess of 3 or
 4  meters per seconds.  At lower wind speeds, plume rise from some of the
 stacks  could be  significant.  Plume rise factors were consequently
 developed, which accounted for the plume rise at  low wind speeds and
 downwash at  higher speeds.  Those factors were then incorporated into the
 dispersion estimates.
     The dispersion estimates were made through application of the
 Climatological  Dispersion  Model  (COM).   The COM provides  estimates of
 long-term pollutant concentrations at selected ground-level  receptors.
The model  uses  average emission  rates from point and area sources and a
joint frequency distribution of  wind direction,  wind speed,  and  stability.
                              9-7

-------
     One year of monthly stability-wind data from Orlando, Florida were
utilized in the COM dispersion estimates.  The climatology of that lo-
cation is representative of that at facilities of concern in this docu-
ment.  The COM estimates are typical high 30-day average ambient fluo-
ride concentrations.  The  results of the analysis are presented in
Table 9-5.  A more general review of 5-year summaries of monthly stability-
wind data from the same location verified that the values presented in
Table 9-5 are representative of typical high 30-day average concentrations
for any given year.
     Table 9-5 shows tjiat  the best technology retrofit controls made a large
reduction in the qrounfl-level fluoride concentrations which has existed when
the mediocre controls were used on the four sources shown.  At distances
greater than about 1-1/2 mile, the concentrations do not exceed 0.5 vg/m3,
even in the most unfavorable months when the emission guidelines herein are
applied.

Table 9-5.   ESTIMATED  30-DAY AVERAGE AMBIENT FLUORIDE CONCENTRATIONS
                 DOWNWIND  OF A  PHOSPHATE  FERTILIZER COMPLEX
Fluoride Sources
Existing Controls
WPPA DAP TSP GTSP

After Retrofit

WPPA DAP TSP GTSP
Estimate
Fluoride
1
6
0.8
2
4
0.6
sd 30-Day Average
5 Concentration
3
3
0.4
5
1.9
0.3
10
1.0
0.1
ug/m )
15 km
0.5
0.1
                             9-8

-------
 9.1.1.2   Emission Guidelines vs. a Tvoical Standard
     The  Florida standard to take effect on July 1, 1975, has been
 chosen as a typical standard to compare with the proposed emission
 guidelines.   Emission reductions listed in Table 9-1 have already
 taken into account  the effect of the  Florida standard in reducing  fluo-
 ride emissions.  Table 9-6 gives the  incremental annual controlled  fluo-
 ride emissions when the emission guideline is substituted for
 a  typical standard.  Emission figures  in this table are based on the
 data in Table 9-1.  In all cases, the  typical standard is as strict or
more so than the -antssion guidelines.
9.1.2  Water Pollution
     Increased or decreased control of gaseous water-soluble fluorides
will not change the amount of liquid waste generated by the phosphate
industry.  Most control systems now in use utilize recycled process
(gypsum pond) water as the scrubbing medium thereby eliminating  the
creation of additional effluent.  Phosphate fertilizer plants do not need
to discharge gypsum pond water continuously.  The pond water is  re-used in
the  process, and a discharge is needed only when there is  rainfall in excess
                             9-9

-------
     Table 9-6.  COMPARISON OF STATE GUIDELINES STANDARD AND AN ALTERNATIVE STANDARD
I
o
Process Source of
Fluorides






Wet Process
Phosphoric Acid
Superphosphoric
Acid

Di ammonium
Phosphate
Triple Super-
phosphate (ROP)

Granular Triple
Superphosphate
Granular Triple
Superphosphate
Storage
Percent of
Plants Probably
Affected by State
Guidelines Standard





47
21


60
40


25

70
Florida Standard
for
duly 1, 1975
Ibs/ton P205





0.02
Best Avail-
able Technology

0.06
Belt & Den 0.05
Storage 0.12

0.15

0.05**

Emission
Guidelines
input





0.02
0.01


0.06
0.2


0.2

5 x 10"4*
Increase in Esti-
mated Controlled
Annual Fluoride
Emissions if
State Guidelines
Standard is Sub-
stituted for
Florida Standard
(Tons F/Yr)

0
0


0
39


33

23
      *Units  are  Ibs  F/hr/ton of P205 stored.
     **Units  are  Ibs  F/hr/ton of P20g input to bldg.

-------
of evaporation.   For this reason, the volume of effluent from phosphate
fertilizer plants is almost exclusively a function of rainfall conditions,
EPA effluent limitations guidelines require that any gypsum pond water
discharged to navigable waters when rainfall exceeds evaporation meet
the limitations in Table 9-7.  A two-stage lime neutralization procedure
combined with settling is sufficient control to meet these limitations.

Table 9-7.  EPA EFFLUENT LIMITATIONS GUIDELINES FOR GYPSUM POND WATER1

Aqueous                     Maximum Daily     Maximum Average of Daily
Waste                       Concentration     Values for Periods of
Constituent                   (mg/1)          Discharge Covering 10 or
                                              More Consecutive Days
                                                     (ng/1)
Phosphorus as (P)
Fluoride as (F)
Total Suspended
nonfilterable solids
70
30

50
35
15

25
 The pH of the water discharged shall be within the range of 8.0 to 9.5
 at all times.
     The phosphate industry has voiced concern that the partial pressure
of  fluoride out of pond water makes it infeasible in some cases to reach
SPNSS fluoride limitations with a scrubber using pond water.  An equili-
brium fluoride concentration between 5000-6000 ppm seems to be estab-
lished in gypsum ponds - possibly because of a slow reaction between
                                 234
gypsum and soluble fluosilicates. ' '  Even a pond with an apparent fluo-
ride concentration of 12,500 ppm has fallen within this equilibrium range
when the water was passed through a millipore filter.,   The excess fluoride
can be attributed to suspended solids.  Pond water containing about 6000

                               9-11

-------
 ppm  of  fluoride  has  a  low enough  partial pressure of fluoride to
 allow scrubber vendors to design  to meet emission guidelines.  In all
 cases,  emission  guidelines can be achieved with pond water
 1f a well-designed spray-crossflow packed bed scrubber 1s used as the
               5
 control device.

 9.1.3   Solid Waste Disposal
     Any solid waste generated by scrubbing fluorides would be in the
 form of CaF2 or  similar precipitates in the gypsum ponds.  The amount
 of precipitate formed  is  negligible in comparison to the amount of
 gypsum  generated in producing wet process phosphoric acid, a required
 intermediate throughout the phosphate fertilizer industry.  An example
 of the  relative  amounts of each of the solids produced in normal  processing
 with scrubbers which meet emission guidellres for a  500
 tons/day P20g WPPA plant.is presented below:
Assumptions:
     1.   6427# phosphate  rock = 1 ton PoOe-
     2.   Phosphate rock is 35 weight percent Ca.
     3.   Uncontrolled emissions of 58.1 #F/hr are reduced to 0.42 #F/hr
         by a scrubber.   (See retrofit model WPPA plant, case B).
     4.   All of  the F absorbed by the scrubber precipitates in the
         gypsum  pond as CaF2.  (See Section 5.2.1, page 5-6).
     5.  The  plant capacity  is  500  tons/day P°-
                              9-12

-------
      3Ca1Q  (P04)g  F2 + 30H2S04 + Si02 + 58H20 •* 30 CaS04
       18H3P04
      This  reaction implies:  40#Ca -*- 172# gypsum.
                        500 x 6427 x 0.35 x 172
      gypsum  produced =  	   = 201,510
                                                     # gypsurn/hr
                               24 x 40
      From assumptions 3 and 4:
      F absorbed in scrubber =58.1 - 0.42 # F/hr
                            = 57.68 # F/hr
      Ca++ +  2F" •+ CaF2 4-                                              (5-1)
      CaF? +  = 57.68 x 78    = 118.4 # CaF9/hr
        ^        38                      z
      % increase in solids =  118.4 x 100      = 0.06
                              201,510
      This example illustrates that the increase In solids due only to
scrubbing fluorides is negligible (0.06%).  The disposal of the
Targe volume of gypsum is by depositing in mined-out areas, and by
lagooning, followed by drying and piling techniques.  Such piles are
as much as 100 feet above grade in some areas.
9.1.4  Energy
     Changes in fluoride control, electrical power requirements for the
spray-crossflow packed bed scrubber retrofit models in Section 6 are
presented in Table 9-8.   Existing fluoride control power requirements
were estimated from the pump and fan requirements for the assumed existing
                               9-13

-------
Table 9-8.  INCREMENTAL POWER REQUIREMENTS  FOR  FLUORIDE CONTROL DUE TO INSTALLATION OF RETROFIT

                                 CONTROLS TO MEET  EMISSION GUIDELINES.



                                                          Power Requirements
                   ran^,-4-        Power Requirements       for Retrofit Controls   AD
                   Capacity       for Existing  Controls    to  Meet  State  Guide-    APower      A Enerqv
Type of Plant    Ton/Day P205           (Hp)               }?„„    SK6  bU1Qe      HP       KWH/Ton PJ

1
4^>



WPPA
SPA
DAP
ROP-TSP
(Case A)
GTSP
500
300
500
550
400
90
75
565
300
540
140
82.5
800
500
1100
50
7.5
235
200
560
1.8
0.4
8.4
6.5
25

-------
 controls in the retrofit models.   Power requirements  for the retrofit
 controls were obtained by adding  the power ratings  of the specified
 retrofit fans and pumps to the existing power requirements and sub-
 tracting the power for any fans or pumps removed in retrofitting.
     The largest incremental  power requirement for fluoride control
 is for GTSP.   This can be attributed to installing  a  spray-crossflow
 packed bed scrubber for GTSP storage,  a previously  uncontrolled source
 in the retrofit model  which  generates  a very  large  volume of air having
 a small  concentration  of fluoride.   Raising the  standard  to allow larger
 emissions  from GTSP storage  would not  greatly reduce  these power require-
 ments.   It would only  allow  the use  of a  scrubber with a  fewer number of
 transfer units.   A less efficient scrubber would  not  reduce the volume
 of gas  to  be  scrubbed  nor would it greatly reduce the amount of pond
 water  required  for scrubbing.   Only  the pressure  drop through  the scrubber
 would  be reduced  by  raising  the standard.  In  other words,  raising  the
 GTSP storage  standard  by a factor of two would not reduce  the  power  require-
 ments  proportionately.
    Incremental increases  in phosphate fertilizer processing energy
 requirements  are given  in Table 9-9; such increases will  vary  from
 plant to plant.  Volumetric flow  rates of fluoride-contaminated air
 sent to  the scrubbers can vary  by a factor of two or three  for  the same
 size and type of plant.  Existing control schemes will also  influence
 incremental power requirements by the extent to which their  pumping
 and fan systems can be adapted.  Therefore, the numbers presented in
Tables 9-8 and 9-9 should be considered approximate.
                             9-15

-------
     Fertilizer processing energy requirements presented in Table 9-Q
are primarily based upon material in reference (6).  The tynes of
energy utilized by the various processes vary.  For example, approximately
50 percent of the energy required in GTSP processing can be attributed to
the 3 gallons of fuel oil used per ton PpOc processed while neerlv all
the energy used in the submorgsc' combustion process for SPA comes from
natural gas.  All processing energy requirements listed in Table 9-9
include electrical power required for rock crushing and pumping.

Table  9-9.  INCREASE IN PHOSPHATE INDUSTRY ENERGY REQUIREMENTS RESULTING
            FROM INSTALLATION OF RETROFIT CONTROLS TO MEET EMISSION GUIDELINES
Fertilizer process
WPPA
DAP*
SPA*
ROP-TSP*
GTSP*
Existing energy
requirements
(KWH/Ton P205)
225
236
782
152
305
Fluoride control
incremental
energy require-
ments
(KWH/Ton P20g)
1.8
8.4
0.4
6.5
25
Percent
increase in
energy re-
auirements
0.8
3.6
0.05
4.3
8.2
*Existing energy requirements figures  include energy needed to process WPPA
feed for process.
     Annual incremental electrical energy demand for fluoride control is
presented in Table  9-10.   These figures  are based  upon Tables 9-6 anc,
9-8 along with  production  statistics  in  section  3.  The  total incremental
                               9-16

-------
     Table 9-10.   INCREASED ELECTRICAL ENERGY DEMAND BY THE PHOSPHATE INDUSTRY AS A RESULT OF INSTALLATION
                                              OF RETROFIT CONTROLS
     Fertilizer Process
VO
  1973 Production
(Thousand Tons P
% of Production Capacity
  Affected by State
  Guidelines Standard
Incremental Electrical
Energy Demand (Million
KWH/yr)
                                                                                                         **
WPPA
DAP
SPA
ROP-TSP
GTSP
5,621
1,860
783
600
1,115
26
60
21
40
47*
2.6
9.6
0.06
1.6
13
     *This is a fictitious average based upon a weighted average of GTSP production and storage

      statistics (see Table 9-6).
    **Total Incremental Electrical Energy Demand = 26.86 x 106 KWH/yr.

-------
electrical energy demand resulting from installation of retrofit con-
trol? to moot om-i^sfAn «iit/l<*lt^s ts ^utYa1 ent t.n the energy required  to
operate one  300 ton/day P205 SPA plant 115 days/yr.  It should be em-
phasized that these numbers  can be only approximations.  As mentioned
in the discussion of Tables  9-8 and 9-9, individual plant fluoride control
energy and power requirements will vary.  This variability necessarily
constrains the accuracy of projections based upon single retrofit models.

9.1.5  Other Environmental Concerns
     Due to  the proposed method of fluoride control, namely, utilization
of a spray-crossflow packed  bed scrubber with pond water as the scrubbing
medium, no other environmental concerns are anticipated.  Scrubbing
fluorides with gypsum pond water produces a closed system effect for
phosphate fertilizer complexes.  Although radioactive materials have been
detected in  the wastewater at fertilizer complexes, recycling of the pond
water to the scrubber is not expected to contribute to this potential problem.7

 9.2   ENVIRONMENTAL  IMPACT UNDER ALTERNATIVE  EMISSION  CONTROL  SYSTEMS
     Analysis of the  data  I ase  on which the emission guidelines are  based
 indicates  that only the  spray-crossflow packed bed  scrubber can meet
emission guidelines in all cases.   ROP-TSP plants can  use cyclonic
spray tower  scrubbers to meet the emission guidelines, but  at a higher
cost than for a spray-crossflow packed bed scrubber (Table  6-44).
Tables 6-37  and 6-40  show that  the ROP-TSP standard  is the only one
substantiated by data which  allows use of an alternative scrubber design.
Use of either scrubber design for controlling  ROP-TSP  plants would result
in similar environmental impacts.  Except for  ROP-TSP  plants, raising
the emission guidelines to allow use of alternative scrubber designs.
would result in a 50 percent to 1000 percent increase  in fluoride
emissions without causing any beneficial environmental impacts.
                                  9-18

-------
9.3  SOCIO-ECONOMIC IMPACTS



     Tha phosphate fcrti "h?..v industry is generally recofimzcci as 5



capital intensive industry, It'bor requirements for nroduction work anc



nlant suuervision arc small, compared to plant sales.   Usually, those



fertilizer facilities which may be affected by the emission



guidelines are widely dispersed throughout the United  States.  Only in



central Florida does the fertilizer industry represent a substantial



portion of overall community economic activity and employment, and



Florida has enacted emission standards effective July  1, 1975 which are



at least as strict as the em'ssion guidelines.  Therefore,  any potential



plant closures as a result of the implementation of lll(d)  regulations



will produce minimal community effects in terms of job losses and sales



revenues.



     Retrofitting existing plants for controls should  not imoede new



plant construction programs.  During the years 1973 through 1974, the



phosphate industry entered an expansionary o!ase with  the ccnsiruction



of several new fertilizer manufacturing comolexes.  The construction



rate i$* expected to decrease after 1976 as these new plants come on-



stream.  Installation of retrofit controls will consequently occur during



a period of slack construction activity and should not interruot the



long-term availability of phosphate fertilizers.
                              9-19

-------
 9.5   REFERENCES

 1.    Martin, Elwood E.  Development Document for Effluent  Limitations
      Guidelines and New Source Performance Standards  for the Basic
      Fertilizer Chemicals.  Environmental  Protection  Agency.  Washington,
      D.C.   Publication Number EPA-440/1-74-011 -a.   March 1974.

 2.    Teller, A.J.   Control of Gaseous  Fluoride  Emissions.  Chemical
      Engineering  Progress.  63^75-79,  March  1967.

 3.    Huffstutler,  K.K.   Pollution  Problems in Phosphoric Acid
      Production.   In:   Phosphoric  Acid, Vol.  I., Slack, A.V. (ed).
      New York,  Marcel  Dekker,  Inc.,  1968.  p. 728.

 4.    Weber,  W.C. and C.J.  Pratt.   Wet-Process Phosphoric Acid Manu-
      facture.   In:  Chemistry  and  Technology of Fertilizers,
      Sauchelli, V.  (ed).   New  York,  Reinhold Publishing Corporation,
      196U.   p.  224.

5.    Crane,  George B.  Telephone Conversation with Dr. Aaron Teller,
     Teller  Environmental  Systems, Inc.  New York, N.Y.  December 13,
      1974.

6.   Bixby, David W. , Delbert L. Rucker, and Samuel  L. Tisdale.
     Phosphatic Fertilizers.  The Sulphur Institute.  Washington,  D.C.
     February 1964.
7.   Rouse, J. V.  Letter.  In: Environmental Science  and Technology.
     Easton, Pa. October 1974.
                                 9-20

-------
                                    TECHNICAL REPORT DATA
                             '//far rcail Injunctions on the rei i-nc before rtimplcl'ns)
   »: r-on i t*o
  . T -|_. A.\O S'Jtii It I i

  Draft Guideline  Document:  Control of Fluoride
  DMSSIOIIS  from listing Phosphate Fertilizer  Plants
   AUIHOrllS)
 9 ff.JTF-OR.VHNG ORGANIZATION NAME AND ADUntSs"
  U. S.  Environmental  Protection Agency
  Office of Air  Quality Planning and Standards
  Research Triangle Park, NC  27711
 1? SPONSORING AGENCY NAMfc AND ADDRESS
                                                            3 FlfcCliMENl'S ACCLSi,iOf*NO
              !j FIEPOR r DATE
               April 1_976 _

              G ft RFOHMING OROANI 'ATlOr.1 CODt"
                                                           8 PEHFORMING ORGANIZATION HtHORl NO
              10 PROGRAM tLLMENT NO "
              11 CONTHACf/GRANT NO
                                                            13 TYPE OF REPORT AND PERIOD COVERED
                                                            14 SPONSORING AGENCY CODE
 15 SUPPLEMENT ARY NOTES
            The  U.  S.  Environmental Protection Agency  is  required under 40 CFR Part  60
 to publish a uuideline  document for development of  State emission standards after
 promulgating any  standard of performance for a designated pollutant.  Standards of
 performance limiting  emissions of such a designated"pollutant--fluorides--from new  ancl
 modified phosphate fertilizer plants were promulgated  on August 6, 1975, necossitatinn
 the development of this guideline document.  The document includes the followino
 information:   (1)  Emission guidelines and times for compliance; (2) A brief descrip-
 tion of the phosphate fertilizer industry, the five manufacturinq categories for
 which emission  guidelines are established, and the  nature and source of fluoride
 emissions; (3)  Information regarding the effects of airborne fluorides on health,
 crops, and animals; and (4) Assessments of the environmental, economic, and enemy
 impacts of the  emission guidelines.  This is a draft guideline document; the final
 document will be  published after receipt and consideration of public comments
 solicited in tfie  FEDERAL REGISTER notice announcing the  document's availability.
17
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DtSCRIPTORS
 Phosphate  Fertilizer Plants
 Fluorides
 Standards  of  Performance
                                              h IDENTIFIERS/OPEN ENDED TERMS
 Air Pollution Control
                                                                        c  COSATI I icId/Group
 Unlimited
19 SfcCURITY CLASS flhit Hipnrri
 Unclassified
20 SECUFiiTY CLASS (This page)
 Unclassified
21 NO OF PAGES
     2.19
                                                                        22 PRICE
EPA Form 2220-1 (9-73)

-------