D A U.S. Environmental Protection Agency Industrial Environmental Research PDA f^C\C\l~7 ~7f\
Cr M Office of Research and Development Laboratory
Cincinnati. Ohio 45268 December 1976
ENVIRONMENTAL
CONSIDERATIONS OF
SELECTED ENERGY
CONSERVING MANUFACTURING
PROCESS OPTIONS:
Vol. XV. Fertilizer
Industry Report
Interagency
Energy-Environment
Research and Development
Program Report
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S.
Environmental Protection Agency, have been grouped into seven series.
These seven broad categories were established to facilitate further
development and application of environmental technology. Elimination
of traditional grouping was consciously planned to foster technology
transfer and a maximum interface in related fields. The seven series
are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
RESEARCH AND DEVELOPMENT series. Reports in this series result from
the effort funded under the 17-agency Federal Energy/Environment
Research and Development Program. These studies relate to EPA's
mission to protect the public health and welfare from adverse effects
of pollutants associated with energy systems. The goal of the Program
is to assure the rapid development of domestic energy supplies in an
environmentallycompatible manner by providing the necessary
environmental data and control technology. Investigations include
analyses of the transport of energy-related pollutants and their health
and ecological effects; assessments of, and development of, control
technologies for energy systems; and integrated assessments of a wide
range of energy-related environmental issues.
This document is available to the public through the National Technical
Information Service, Springfield, Virginia 22161.
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EPA-600/7-76-034o
December 1976
ENVIRONMENTAL CONSIDERATIONS OF SELECTED
ENERGY CONSERVING MANUFACTURING PROCESS OPTIONS
Volume XV
FERTILIZER INDUSTRY REPORT
EPA Contract No. 68-03-2198
Project Officer
Herbert S. Skovronek
Industrial Pollution Control Division
Industrial Environmental Research Laboratory - Cincinnati
Edison, New Jersey 08817
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 30402
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DISCLAIMER
This report has been reviewed by the Industrial Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for publica-
tion. Approval does not signify that the contents necessarily reflect the
views and policies of the U.S. Environmental Protection Agency, nor does
mention of trade names or commercial products constitute endorsement or
recommendation for use.
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FOREWORD
When energy and material resources are extracted, processed, converted,
and used, the related pollutional impacts on our environment and even on our
health often require that new and increasingly more efficient pollution con-
trol methods be used. The Industrial Environmental Research Laboratory -
Cincinnati (lERL-Ci) assists in developing and demonstrating new and im-
proved methodologies that will meet these needs both efficiently and
economically.
This study, consisting of 15 reports, identifies promising industrial
processes and practices in 13 energy-intensive industries which, if imple-
mented over the coming 10 to 15 years, could result in more effective uti-
lization of energy resources. The study was carried out to assess the po-
tential environmental/energy impacts of such changes and the adequacy of
existing control technology in order to identify potential conflicts with
environmental regulations and to alert the Agency to areas where its activi-
ties and policies could influence the future choice of alternatives. The
results will be used by the EPA's Office of Research and Development to de-
fine those areas where existing pollution control technology suffices, where
current and anticipated programs adequately address the areas identified by
the contractor, and where selected program reorientation seems necessary.
Specific data will also be of considerable value to individual researchers
as industry background and in decision-making concerning project selection
and direction. The Power Technology and Conservation Branch of the Energy
Systems-Environmental Control Division should be contacted for additional
information on the program.
i David G. Stephan
Director
Industrial Environmental Research Laboratory
Cincinnati
111
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EXECUTIVE SUMMARY
The function of the fertilizer industry is to provide farmers with
the three basic plant nutrients nitrogen, phosphorus, and potassium
in a form and proportion suitable for particular crops and soils. This
requires the production of intermediate products through chemical reaction,
mixing or blending, and an extensive distribution system. In this report,
the definition of the fertilizer industry excludes the mining or manufac-
ture of raw materials, such as ammonia, phosphate rock, sulfur, and potash.
In fact, most of the industry's energy consumption (78 x 1012 Btu/yr)
is in the manufacture and mining of raw materials, and not in the subsequent
processes. However, the fertilizer industry treated in this report con-
sumed 52 x 1012 Btu in 1973. Almost half was as electric power. The
remainder was mostly natural gas, but natural gas use is declining in favor
of fuel oil and LPG.
We foresee no process changes being made in the fertilizer industry
(as defined herein) solely from the desire to conserve energy. The major
cost components in the fertilizer industry are raw materials; investment
and working capital-related costs are second; and other items such as energy
and labor are usually insignificant. While changes in product mix and
processes are likely over time, such changes will be the result of factors
other than energy conservation.
There are two areas where environmental regulations and energy conser-
vation are in conflict. These are:
The reduction of nitrogen oxide emissions from nitric acid
plants; and
Switching from natural gas to fuel oil for firing fertilizer
dryers, where emissions are presently controlled by bag filters.
The most widely used process for control of nitrogen oxide emissions
in nitric acid plants is the catalytic decomposition of nitrogen oxides to
nitrogen and oxygen. This process is capital- and energy-intensive, and
is particularly expensive for those few nitric acid plants that cannot
recover the energy in the form of steam. The problem is aggravated because
natural gas is the required energy source, and most plants are limited in
the quantities of gas they can purchase. Natural gas use for pollution
IV
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control reduces the amount available for other purposes, thus effectively
reducing production. The annual natural gas requirement for pollution con-
trol of a 300-ton-per-day nitric acid plant could be used to produce 6,600
tons of ammonia, including process fuel requirements, or about 11,000 tons
of ammonia if used only for feedstock.
Other abatement systems are becoming available and hold the promise
of lower investment and operating costs, significantly lower energy require-
ments, and no need for natural gas as the energy source. However, these
other processes currently suffer in various ways from problems of mainte-
nance, of stringent operating conditions ("Molecular Sieve"), inapplicability
to low-pressure nitric acid processes ("Grade Paroisse"), and too little
actual experience (CDL/Vitok).
We found that only 10-20% of the ammoniation granulation fertilizer
plants in the country use bag filters to collect the considerable dust
generated by the process; others use wet scrubbers. The need to shift to
fuel oil because of the scarcity of natural gas has caused problems in
operating the bag filters, because of the premature clogging of the filter
for a variety of reasons, including incomplete combustion of fuel oil,
increased soot and ash formation, and deposition of sulfate salts on the
bags. We have found that these problems can be overcome, short of replac-
ing the bag collectors with wet scrubbers or short of shutting down the
plant. It will require upgrading the burner equipment, gaining experience,
and improving operating procedures.
Areas for further research or other types of action are:
Determining the applicability of the new processes to control
nitrogen oxides emissions from sources other than nitric acid
plants;
Developing methods of alleviating the problems of startup, shut-
down, and malfunction of the nitrogen oxide abatement equipment;
and
Disseminating information on techniques for using bag filters in
conjunction with oil-fired dryers.
This report was submitted,1 in partial fulfillment of contract 68-03-2198
by Arthur D. Little, Inc. under sponsorship of the U.S. Environmental Protec-
tion Agency. This report covers a period from June 9, 1975 to January 16, 1976.
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TABLE OF CONTENTS
Page
FOREWORD ±il
EXECUTIVE SUMMARY iv
List of Figures ,
List of Tables x
Acknowledgments x^
Conversion Table xiv
I. INTRODUCTION 1
A. BACKGROUND 1
B. CRITERIA FOR INDUSTRY SELECTION 1
C. CRITERIA FOR PROCESS SELECTION 3
D. SELECTION OF FERTILIZER INDUSTRY PROCESS OPTIONS 3
1. Process Options Selected 3
2. Method of Analysis 4
II. FINDINGS, CONCLUSIONS, AND RECOMMENDATIONS 6
A. ENERGY CONSERVATION MEASURES IN CONFLICT WITH POLLUTION
CONTROLS 6
1. Nitric Acid 6
2. Fertilizer Mixing 7
B. PRACTICES/PROCESSES REQUIRING ADDITIONAL RESEARCH 9
III. FERTILIZER INDUSTRY OVERVIEW 10
A. DESCRIPTION 10
1. Industry Sectors 10
2. Integration 13
3. Energy Use 15
4. Plant Characteristics 15
B. OUTLOOK , 17
1. Nitrogen Fertilizers 17
2. Nitric Acid 21
3. Mixed Fertilizers 23
IV. COMPARISON OF CURRENT AND ALTERNATIVE PROCESSES 24
A. REASONS FOR CHOOSING OPTIONS TO BE ANALYZED IN DEPTH 24
1. Air Pollution Control in Nitric Acid Plants 24
2. Conversion to Fuel Oil for Drying in Mixed Fertilizer
Plants Equipped with Bag Filters 24
vii
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TABLE OF CONTENTS (Cont.)
Page
B. COMPARISONS OF CURRENT AND ALTERNATIVE PROCESSES 25
1. Nitric Acid 25
2. Conversion to Fuel Oil in Mixed Fertilizer Plants
Equipped With Big Filters 43
V. IMPLICATIONS OF POTENTIAL CHANGES 56
A. AIR POLLUTION CONTROL IN NITRIC ACID PLANTS 56
B. FERTILIZER DRYING 57
1. Continued Use of Bag House With Improved Design
and Operation 57
2. Conversion From Bag House to Wet Scrubber With Fuel
Change From Natural Gas to Fuel Oil 58
viii
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LIST OF FIGURES
Number Page
IV-1 Bag House Collector and Plate Type Scrubber 26
IV-2 Particulate Collection Efficiencies for Various Types of
Control Equipment 27
IV-3 Flow Diagram of a Typical 300-Ton-Per-Day Nitric Acid
Plant Utilizing the Pressure Process 28
IV-4 Total NOX (Calculated as N02)/Hour vs Daily Production
of Nitric Acid 32
IV-5 Grande Paroisse NOY Abatement Process 37
A.
IV-6 Masar Process for NOX Abatement 40
IV-7 Batch-Mixer, Pug-Mill and Rotary-Drum Ammoniation 44
IV-8 Simplified Flow Diagram of an Ammoniation Granulation Plant 45
IV-9 Detailed Schematic Diagram of Rotary-Drum Ammoniation Plant 46
IV-10 Detail of Granulation Plant Dust Collection System 47
ix
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LIST OF TABLES
Number Page
1-1 Summary of 1971 Energy Purchased in Selected Industry Sectors 2
II-l Comparison of Energy, Pollution Control, Economics, Energy Use
for Alternative Nitric Acid Processes 8
III-l Integration of Leading Ammonia Producers 14
III-2 Energy Use in Fertilizer Manufacture - 1973 16
III-3 Granulation Plants in United States 18
III-4 Fertilizer Nitrogen Consumption 21
III-5 Nitric Acid Production 22
III-6 Future Nitric Acid Demand 22
IV-1 Production Costs 30
IV-2 Nitrogen Oxide Emissions from Nitric Acid Plants 31
IV-3 Average Composition of Tail Gas from the Pressure Process 31
IV-4 Capital and Operating Costs for Different NOX Abatement
Systems in a 300 TPD Nitric Acid Plant 34
IV-5 Energy Requirements in NOX Abatement Systems for A 300 TPD
Nitric Acid Plant 35
IV-6 Basis for Tables IV-4 and IV-5 35
IV-7 Emissions Data for Nitric Acid Plants Having Alkaline
Scrubbing Equipment 42
IV-8 Ammoniation Granulation Production Statistics - 1973 48
IV-9 Uncontrolled Emission Factors for Ammoniation Granulation
Plants 49
IV-10 Emission Factor and Total Mass of Controlled Emission from
Fertilizer Mixing Plants 50
IV-11 Mixed Fertilizer Plant Scrubber Costs 51
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LIST OF TABLES (Cont.)
Number Page
IV-12 Mixed Fertilizers - Fuel Oil Alternative Scrubber Water
Treatment Costs 52
IV-13 Mixed Fertilizer Plant Bag House Costs 54
IV-14 Fertilizer Drying, Costs for Main and Auxiliary Burners 54
IV-15 Fertilizer Drying, Incremental Cost of Burning Fuel Oil
with Bag Filters 55
V-l Capital Cost and Operating Cost for NOX Abatement Systems
for a 300 TPD Nitric Acid Plant 57
V-2 Energy Requirement in NOX Abatement Systems for a 300 TPD
Nitric Acid Plant 58
V-3 Comparison of Scrubber and Bag House Costs and Energy
Consumption for Treating Mixed Fertilizer Plant Gaseous
and Particulate Wastes 59
xi
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ACKNOWLEDGMENTS
This study could not have been accomplished without the support of a
great number of people in government agencies, industry, trade associations
and universities. Although it would be impossible to mention each individual
by name, we would like to take this opportunity to acknowledge the particular
support of a few such people.
Dr. Herbert S. Skovronek, Project Officer, was a valuable resource to us
throughout the study. He not only supplied us with information on work
presently being done in other branches of EPA and other government agencies,
but served as an indefatigable guide and critic as the study progressed. His
advisors within EPA, FEA, DOC, and NBS also provided us with insights and
perspectives valuable for the shaping of the study.
During the course of the study we also had occasion to contact many
individuals within industry and trade associations. Where appropriate we
have made reference to these contacts within the various reports. Frequently,
however, because of the study's emphasis on future developments with compara-
tive assessments of new technology, information given to us was of a confiden-
tial nature or was supplied to us with the understanding that it was not to be
credited. Therefore, we extend a general thanks to all those whose comments
were valuable to us for their interest in and contribution to this study.
Finally, because of the broad range of industries covered in this study,
we are indebted to many people within Arthur D. Little, Inc. for their parti-
cipation. Responsible for the guidance and completion of the overall study were
Mr. Henry E. Haley, Project Manager; Dr. Charles L. Kusik, Technical Director;
Mr. James I. Stevens, Environmental Coordinator; and Ms. Anne B. Littlefield,
Administrative Coordinator.
Members of the environmental team were Dr. Indrakumar L. Jashnani,
Mr. Edmund H. Dohnert and Dr. Richard Stephens (consultant).
Within the individual industry studies we would like to acknowledge the
contributions of the following people.
Iron and Steel: Dr. Michel R. Mounier, Principal Investigator
Dr. Krishna Parameswaran
Petroleum Refining: Mr. R. Peter Stickles, Principal Investigator
Mr. Edward Interess
Mr. Stephen A. Reber
Dr. James Kittrell (consultant)
Dr. Leigh Short (consultant)
xii
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Pulp and Paper:
Olefins:
Ammonia:
Aluminum:
Textiles:
Cement:
Glass:
Chlor-Alkali:
Phosphorus/
Phosphoric Acid;
Primary Copper:
Fertilizers:
Mr. Fred D. lannazzi, Principal Investigator
Mr. Donald B. Sparrow
Mr. Edward Myskowski (consultant)
Mr. Karl P. Pagans
Mr. G. E. Wong
Mr. Stanley E. Dale, Principal Investigator
Mr. R. Peter Stickles
Mr. J. Kevin O'Neill
Mr. George B. Hegeman
Mr. John L. Sherff, Principal Investigator
Ms. Nancy J. Cunningham
Mr. Harry W. Lambe
Mr. Richard W. Hyde, Principal Investigator
Ms. Anne B. Littlefield
Dr. Charles L. Kusik
Mr, Edward L. Pepper
Mr. Edwin L. Field
Mr, John W. Rafferty
Dr. Douglas Shooter, Principal Investigator
Mr, Robert M. Green (consultant)
Mr, Edward S, Shanley
Dr, John Willard (consultant)
Dr.. Richard F, Heitmiller
Dr, Paul A. Huska, Principal Investigator
Ms. Anne B. Littlefield
Mr., J.. Kevin O'Neill
Dr, D. William Lee, Principal Investigator
Mr, Michael Rossetti
Mr, R, Peter Stickles
Mr, Edward Interess
Dr, Ravindra M. Nadkarni
Mr. Roger E. Shamel, Principal Investigator
Mr, Harry W. Lambe
Mr% Richard P. Schneider
Mr. William V. Keary, Principal Investigator
Mr. Harry W. Lambe
Mr. George C. Sweeney
Dr, Krishna Parameswaran
Dr. Ravindra M. Nadkarni, Principal Investigator
Dr, Michel R. Mounier
Dr, Krishna Parameswaran
Mr. John L. Sherff, Principal Investigator
Mr. Roger Shamel
Dr. Indrakumar L. Jashnani
xiii
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ENGLISH-METRIC (SI) CONVERSION FACTORS
To Convert From
Acre
Atmosphere (normal)
Barrel (42 gal)
British Thermal Unit
Centipoise
Degree Fahrenheit
Degree Rankine
Foot
Foot /minute
Foot3
Foot2
Foot/sec
2
Foot /hr
Gallon (U.S. liquid)
Horsepower (550 ft-lbf/sec)
Horsepower (electric)
Horsepower (metric)
Inch
Ki lowat t-hour
Litre
Micron
Mil
Mile (U.S. statute)
Poise
Pound force (avdp)
Pound mass (avdp)
Ton (assay)
Ton (long)
Ton (metric)
Ton (short)
Tonne
To
2
Metre
Pascal
3
Metre
Joule
Pascal-second
Degree Celsius
Degree Kelvin
Metre
Metre /sec
Metre3
2
Metre
Metre/sec
2
Metre /sec
Metre3
Watt
Watt
Watt
Metre
Joule
Metre
Metre
Metre
Metre
Pascal-second
Newton
Kilogram
Kilogram
Kilogram
Kilogram
Kilogram
Kilogram
Multiply By
4,046
101,325
0.1589
1,055
0.001
t° = (tj -32)/1.8
'K = tR/1'8
0.3048
0.0004719
0.02831
0.09290
0.3048
0.00002580
0.003785
745.7
746.0
735.5
0.02540
3.60 x 106
1.000 x 10~3
1.000 x 10~6
0.00002540
1,609
0.1000
4.448
0.4536
0.02916
1,016
1,000
907.1
1,000
Source: American National Standards Institute, "Standard Metric Practice
Guide," March 15, 1973. (ANS72101-1973) (ASTM Designation E380-72)
xiv
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I. INTRODUCTION
A. BACKGROUND
Industry in the United States purchases about 27 quads* annually,
approximately 40% of total national energy usage.** This energy is used for
chemical processing, raising steam, drying, space cooling and heating,
process stream heating, and miscellaneous other purposes.
In many industrial sectors energy consumption can be reduced significantly
by better "housekeeping" (i.e., shutting off standby furnaces, better thermo-
stat control, elimination of steam and heat leaks, etc.) and greater emphasis
on optimization of energy usage. In addition, however, industry can be
expected to introduce new industrial practices or processes either to conserve
energy or to take advantage of a more readily available or less costly fuel.
Such changes in industrial practices may result in changes in air, water or
solid waste discharges. The EPA is interested in identifying the pollution
loads of such new energy-conserving industrial practices or processes and in
determining where additional research, development, or demonstration is needed
to characterize aad control the effluent streams.
B. CRITERIA FOR INDUSTRY SELECTION
In the first phase of this study we identified industry sectors that
have a potential for change, emphasizing those changes which have an
environmental/energy impact.
Industries were eliminated from further consideration within this assign-
ment if the only changes that could be envisioned were:
energy conservation as a result of better policing or "housekeeping,"
better waste heat utilization,
i
fuel switching in steam raising, or
power generation.
*1 quad = ID3-5 Btu
**Purchased electricity valued at an approximate fossil fuel equivalence of
10,500 Btu/kWh.
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After discussions with the EPA Project Officer and his advisors, industry
sectors were selected for further consideration and ranked using:
Quantitative criteria based on the gross amount of energy (fossil
fuel and electric) purchased by industry sector as found in U.S.
Census figures and from information provided from industry sources.
The fertilizer industry purchased 0.078 quads out of the 12.14
quads purchased in 1971 by the 13 industries selected for study,
or 0.3% of the 27 quads purchased by all industry (see Table 1-1).
Qualitative criteria relating to probability and potential for process
change, and the energy and effluent consequences of such changes.
In order to allow for as broad a coverage of technologies as possible, we
then reviewed the ranking, eliminating some industries in which the process
changes to be studied were similar to those in another industry planned for
study. We believe the final ranking resulting from these considerations identi-
fies those industry sectors which show the greatest possibility of energy con-
servation via process change. Further details on this selection process can be
found in the Industry Priority Report prepared under this contract (Volume II).
On the basis of this ranking method, the fertilizer industry appeared in
thirteenth place among the 13 industrial sectors listed.
TABLE 1-1
SUMMARY OF 1971 ENERGY PURCHASED IN SELECTED INDUSTRY SECTORS
Industry Sector
1. Blast furnaces and steel mills
2. Petroleum refining
3. Paper and allied products
4. Oleflns
5. Ammonia
6. Aluminum
7. Textiles
8. Cement
9. Glass
10. Alkalies and chlorine
11. Phosphorus and phosphoric
acid production
12. Primary copper
13. Fertilizers (excluding ammonia)
(1)
1015 Btu/Yr.
3.49(1)
2.96(2>
1.59
0.984<3)
0.63<4>
0.59
0.54
0.52
0.31
0.24
0.12(5>
0.081
0.078
SIC Code
In Which
Industry Found
3312
2911
26
2818
287
3334
22
3241
3211, 3221, 3229
2812
2819
3331
287
(2)
(3)
(4)
(5)
Estimate for 1967 reported by FEA Project Independence Blueprint,
p. 6-2, USGPO, November 1974.
Includes captive consumption of energy from process byproducts
(FEA Project Independence Blueprint)
Oleflns only, Includes energy of feedstocks: ADL estimates
Amonla feedstock energy included: ADL estimates
ADL estimates
Source: 1972 Census of Manufactures, EPA Project Independence Blueprint,
USGPO, November 1974, and ADL estimates.
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C. CRITERIA FOR PROCESS SELECTION
In this study we have focused on identifying changes in the primary
production processes which have clearly defined pollution consequences. In
selecting those to be included in this study, we have considered the needs
and limitations of the EPA, as discussed more completely in the Industry
Priority Report mentioned above. Specifically, energy conservation has been
defined broadly to include, in addition to process changes, conservation of
energy form (gas, oil, coal) by a process or feedstock change. Natural gas
has been considered as having the highest energy form value followed in
descending order by oil, electric power, and coal. Thus, a switch from gas to
electric power would be considered energy conservation because electric power
could be generated from coal, existing in abundant reserves in the United
States in comparison to natural gas. Moreover, pollution control methods
resulting in energy conservation have been included within the scope of this
study. Finally, emphasis has been placed on process changes with near-term
rather than long-term potential within the 15-year span of time of this study.
In addition to excluding from consideration better waste heat utilization,
"housekeeping," power generation, and fuel switching, as mentioned above,
certain options have been excluded to avoid duplicating work being funded
under other contracts and to focus this study more strictly on "process
changes." Consequently, the following have also not been considered to be
within the scope of work:
Carbon monoxide boilers (however, unique process vent streams
yielding recoverable energy could be mentioned);
Fuel substitution in fired process heaters;
Mining and milling, agriculture, and animal husbandry;
Substitution of scrap (such as reclaimed textiles, iron,
aluminum, glass, and paper) for virgin materials;
Production of synthetic fuels from coal (low-and high-Btu gas,
synthetic crude, synthetic fuel oil, etc.); and
All aspects of industry-related transportation (such as trans-
portation of raw material).
i
D. SELECTION OF FERTILIZER INDUSTRY PROCESS OPTIONS
1. Process Options Selected
After excluding ammonia manufacture (treated in a separate report) from
the fertilizer industry sector, the remaining energy use is relatively low,
and thus, the low priority accorded the industry in this study. Furthermore,
much of the energy conservation potential will entail areas excluded from
this study such as "housekeeping," better heat recovery from waste streams,
and fuel switching. However, in the course of work done for the Federal
-------
Energy Administration in 1974 (Economic Impact of Shortages on the Fertilizer
Industry, No. PB 240418, January 1975), we uncovered two problem areas where
energy conservation and pollution control were in conflict. After discussion
with the Project Officer, it was decided that these two problem areas would be
investigated in greater depth, even though they do not precisely fit the defini-
tion of "process changes for energy conservation purposes." These two areas
are:
(1) The reduction of nitrogen oxide emissions from nitric acid plants.
In this study, we have considered the major emission control
options of:
Catalytic Reduction,
Molecular Sieve,
Grande Paroisse,
CDL/Vitok, and
Masar.
(2) Switching from natural gas to fuel oil for firing fertilizer dryers
where emissions are presently controlled by bag filters. In this
study, we have considered the options of:
Better equipment/technique, and
Installing scrubbers.
Excluded from our analysis were the mining aspects of the fertilizer
industry. Major mining operations are conducted by and for the industry to
produce phosphate rock, sulfur, and potash. These are included in SIC Group
14, "Mining and Quarrying of Non-Metallic Minerals, Except Fuels." Fertilizers
included in this study are included in SIC Groups 2873, 2874, and 2875.
2. Method of Analysis
a. Nitric Acid
We first reviewed the literature to determine the available processes for
pollution abatement in nitric acid plants and reviewed this list with those in
the industry who are knowledgeable in this area to determine which processes
held the most promise. Suppliers of the most promising air pollution control
devices were contacted, and technical and economic information on these
processes was obtained. We also contacted several of the users of these
air pollution devices to determine their experience with them. This in-
formation was then used to prepare our analysis. Our engineering judgment
was used to assess the feasibility of these processes, applicability to
new and existing plants, technical problems which may be encountered, and
to make economic comparisons among them.
b. Fertilizer Drying
Our concern was only with those fertilizer granulation plants which use
bag filtration as a method of particulate control. We contacted several
fertilizer manufacturers and determined that three major companies account for
about half of such plants in the country. These companies were contacted to
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determine their experience in converting such dryers from natural gas to fuel
oil, and their opinions were elicited as to how the problems could be over-
come. We also held discussions with a furnace manufacturer and a producer
of bag filters to obtain similar information. This information was combined
with our own prior knowledge on the costs of conducting the various options
provided us to prepare an analysis which will show whether such conversion from
natural gas to fuel oil is feasible, how it might best be accomplished, and the
cost.
The industry description in this report is based on 1974, the last
representative year for the industry for which good statistical information
was available. Recognizing that capital investments and energy costs have
escalated rapidly in the past few years and have greatly distorted the
traditional basis for making cost comparison, we believe that the most meaning-
ful economic assessment of new process technology can only be made by using
1975 cost data to the extent possible. Consequently, in estimating operating
costs, we have developed costs representative of the first half of 1975 using
constant 1975 dollars for our comparative analysis of new and current processes.
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II. FINDINGS, CONCLUSIONS, AND RECOMMENDATIONS
A. ENERGY CONSERVATION MEASURES IN CONFLICT WITH POLLUTION CONTROLS
1. Nitric Acid
The manufacture of nitric acid generates significant emissions of
nitrogen oxides to the atmosphere. The most widely used process for pollu-
tion control is the catalytic decomposition of these nitrogen oxides to
nitrogen and oxygen. This process is energy intensive and is particularly
expensive for those nitric acid plants which cannot recover the energy in
the form of usable steam. The problem is aggravated because natural gas is
the required energy source. Most plants are limited'in the quantities of
gas they can purchase, and such natural gas is critical and non-substitutable
for the manufacture of ammonia, which in most cases occurs at the same site.
Natural gas use for pollution control reduces the amount available for other
purposes, thus effectively reducing production. The natural gas requirement
for pollution control of a 300-tpd-nitric-acid plant is 232.6 x 10^ Btu per
year. This amount could be used to produce 6,600 tons of ammonia, including
process fuel requirements, or about 11,000 tons if used only for feedstock.
The catalytic reduction process produces steam, which may be used else-
where in the plant complex, and it may be argued that this reduces the energy
input at some other point. Such argument may not be valid for two reasons:
first, not all plants have use for the steam; and, second, such steam, if
needed, could otherwise be provided with a fuel other than natural gas.
Other abatement systems are becoming available and hold the promise of
lower investment costs, lower operating costs, significantly lower energy
requirements, and no need for natural gas as the energy source. Also, because
the catalytic reduction process is usually too expensive to operate in plants
using low-pressure processes to produce nitric acid, two or three of the
alternate processes allow more economical recovery for such plants. However,
the other processes suffer from problems of maintenance of stringent operating
conditions (Molecular Sieve), inapplicability to low pressure nitric acid
processes (Grand Paroisse), and too little actual experience (CDL/Vitok).
Investment in a 300-ton-per-day nitric acid plant with no pollution
control would be about $5,500,000; while the cost of manufacture, including
profit, would be $56.48 per ton. The catalytic reduction process for con-
trolling nitrogen oxide emissions would require an additional investment of
$1,384,000 and would add $6.16 per ton to the manufacturing cost, including
profit. These costs are quite significant, representing a 25% addition in
investment and an 11% increase in the total cost of manufacture.
-------
The four alternative processes studied improve on these costs. The
Molecular Sieve and Grande Paroisse processes entail investments on the
order of $1.2 million and $1.0 million, respectively, and add $4.01 and
$2.30 per ton to the cost of nitric acid. These figures are still significant,
but are lower than for the catalytic reduction process.
The newer processes should result in even better economics. The
CDL/Vitok requirements and Masar processes should have investment of
$575,000 and $663,000, respectively, and add $1.58 to $1.92 per ton to the
manufacturing cost.
Energy requirements are also much lower in each of the four alternatives
to the catalytic reduction process. Not only is energy use lower in the
other processes, but there is no requirement for natural gas. Energy is
consumed as electricity only in three of the options, with electricity and
fuel oil needed for the Molecular Sieve option. These processes are compared
in Table II-l.
2. Fertilizer Mixing
In the drying of mixed granular fertilizers, considerable dust is
generated, which must be removed from the process air stream before it is
vented to the atmosphere.
In switching from natural gas to fuel oil for firing the fertilizer dryer,
manufacturers have encountered operating difficulties with the bag filter.
The problem arises from premature clogging of the filter for a variety of
reasons, including incomplete combustion of the fuel oil, increased soot and
ash formation, and, in the case of high-sulfur fuel oil, deposition of sulfate
salts on the bag. To avoid these problems, some plants have switched to
propane rather than to fuel oil. The scarcity and high price of propane make
this an infeasible alternative for an extended period of time.
We estimate that only about 20% of the estimated 200 ammoniation-
granulation plants being considered use bag filters to collect the dusts; the
remainder use scrubbers. Thus, while the switch from natural gas to fuel oil
will present problems to a few plants, the problem is not highly significant
when viewed in an industry-wide context.
The options available to those plants that now employ bag filters to con-
trol particulate emissions and who must convert to fuel oil are:
Upgrade the burner equipment and operating procedures to minimize
or eliminate the problems just described;
Install alternate control equipment, such as a wet scrubber to
reduce particulate emissions; or
Shut down.
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TABLE II-l
COMPARISON OF ENERGY, POLLUTION CONTROL, ECONOMICS, ENERGY USE
FOR ALTERNATIVE NITRIC ACID PROCESSES
No
Control
(Base Case)
00
Energy Consumption (10 Btu/ton
product)
Gross
Net of Steam Credit
Investment ($ Thousands)
Base 300 tpd Plant
Pollution Control
Total
Operating Costs ($/ton product)
Base 300 tpd Plant
Pollution Control
Total
1.6
0.9
5500
5500
56.48
56.48
Catalyst
Reduction
4.0
2.0
5500
1384
6884
56.48
6.16
62.64
Molecular
Sieve
2.0
1.3
5500
1200
6700
56.48
4.01
60.49
Grande
Paroisse
1.7
1.0
5500
1000
6500
56.48
2.30
58.78
CDL/
Vitok
1.8
1.2
5500
575
6075
56.48
1.58
58.06
Masar
1.6
1.0
5500
663
6163
56.48
1.92
58.40
Includes a 20% pretax return on investment.
-------
Based on the results of our analysis and discussions with mixed ferti-
lizer producers, we believe that it will be possible to upgrade burner
equipment and operating procedures and to avoid the other two alternatives.
B. PRACTICES/PROCESSES REQUIRING ADDITIONAL RESEARCH
For nitric acid plants, it will be beneficial in terms of energy con-
servation to use processes other than catalytic reduction. Fortunately, such
other processes require less capital and lower operating costs. Thus, the
industry will likely opt for such alternatives of free choice and will not
require outside influence.
It would be useful to study the applicability of these new processes to
control NOX emissions from sources other than nitric acid plants.
While control is adequate at steady state, it is not adequate during
startup and shutdown. Also, the pollution control device is complex and
may have to be shut down even though the basic plant continues to operate.
Methods of alleviating these problems are worthy of further study.
For fertilizer drying, the most appropriate action is to disseminate
information on techniques for using bag filters in conjunction with oil-fired
dryers.
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III. FERTILIZER INDUSTRY OVERVIEW
A. DESCRIPTION
The essential function of the fertilizer industry is to produce a
variety of solid and liquid fertilizer products containing one or more of
the three essential chemical plant nutrients nitrogen, phosphorus, and
potassium. In this chapter, we describe the basic chemical processes
associated with the production of the principal materials, the overall
structure of the industry, and factors relating to energy consumption in
the various processing operations. Also included are comments relative to
the non-fertilizer use of certain of the basic chemicals whose primary use
is for fertilizer.
1. Industry Sectors
a. Nitrogen Fertilizers
Ammonia is the basic raw material for virtually all nitrogen fertilizers,
in addition to its direct use as a fertilizer material. Furthermore, sub-
stantial quantities are also used for the production of non-fertilizer
materials, including plastics, resins, nitric acid, etc.
The principal fertilizer products produced from ammonia include urea,
ammonium nitrate, ammonium phosphate, and complete mixed fertilizers. Nitric
acid is produced from ammonia. Ammonium nitrate is the reaction product
of nitric acid and ammonia. Substantial quantities of ammonium nitrate
are used for explosive purposes in surface mining applications. Similarly,
urea finds significant uses outside of the fertilizer industry, principally
as an animal feed, and as a component of thermo-setting resins.
International trade in nitrogen fertilizers is significant for the U.S.
industry. Because of geographical and individual company considerations,
there are generally simultaneous, and in many cases balancing, exports
and imports of anhydrous ammonia and the principal nitrogen fertilizers.
Because of the potential limited availability of natural gas for further
ammonia plant expansions, the United States may become a major net importer
of nitrogen fertilizers in the not-too-distant future. However, the poten-
tial for shifting to coal as a feedstock may obviate the need for such
import dependence. (This is discussed further in the Ammonia Industry
Report, Vol. XII of this study.)
10
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b. Phosphates
The United States is one of the few countries with major reserves of
phosphate rock, which is the basic raw material for phosphate fertilizers
and industrial phosphates. Major commercial deposits are currently being
operated in Florida, North Carolina, Tennessee, and the Mountain states.
Most of the rock mined is transformed into derivative products, but large
volumes are also exported as is.
To be useful as a fertilizer, the phosphate values in phosphate rock
must be transformed into a soluble form. This is generally done by treat-
ing the rock with sulfuric acid to produce either superphosphate or phos-
phoric acid. Superphosphate is a fertilizer which is used as such or as a
component of a mixture containing other nutrients. It has a low nutrient
concentration, and, because of this has lost market share to higher analy-
sis products based on phosphoric acid. Phorphoric acid is used to produce
a variety of solid derivatives, including triple superphosphate, various
grades of ammonium phosphates, and complete mixed fertilizers.
A major part of phosphoric acid production is located adjacent to the
mining operations. However, there are substantial manufacturing facilities
for phosphoric acid located elsewhere, principally in the New Orleans area
and in the upper Midwest.
c. Potash
Potassium, the third major plant nutrient, is found in significant
commercial deposits in Carlsbad, New Mexico, as well as in lesser quantities
in Utah and in various brine operations, including the Great Salt Lake and
Searles Lake in California. The principal potash mineral currently being
mined is muriate of potash (potassium chloride), and sulfate of potash.
Both can be used as mined (after some refining) directly as a fertilizer
material.
The development of a major potash deposit in Saskatchewan has served
to shift the center of North American potash production from the United
States to Canada. The reserves in Saskatchewan are vast in quantity and
of substantially higher grade than the Carlsbad deposits, whose life is
limited.and whose grade is declining. Therefore, the U.S. consumption of
potash is increasingly dependent on Canadian materials, although Carlsbad
continues to operate. However, recent price increases, together with polit-
ical uncertainties in Saskatchewan, have served to reinforce the continued
development of the Carlsbad potash operations.
A minor amount of the potash that is mined perhaps 10% is used
for various non-fertilizer uses, such as in the production of potassium
hydroxide, refined potassium salts, and other miscellaneous potassium
chemicals. Fertilizer potash is used either directly as a fertilizer or as a
raw material for the production of mixed fertilizers.
11
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d. Mixed Fertilizer Production
Until the mid-1950's, the predominant form of fertilizer used by the
U.S. farmer was as a mixture of two or three of the major plant nutrients
supplying nitrogen, phosphorus, and potassium. These were most commonly
based on superphosphate produced by the limited acidulation of phosphate
rock with sulfuric acid. To this was added nitrogen and potash materials
(such as ammonium sulfate, ammonium nitrate, and muriate of potash). Mixed
fertilizers still constitute an important portion of overall fertilizer
use, although the use of single-nutrient materials has displaced a major
part of mixed-fertilizer demand.
However, because of increasing demand for higher nutrient content in
fertilizers, the manufacture of mixed fertilizer has tended away from those
based on normal superphosphate (20% ^2^5^ to materials produced from phos-
phoric acid (54% ?205) and its derivatives. Requisite quantities of addi-
tional nitrogen materials such as ammonia, ammonium nitrate, and muriate
of potash are added to the liquid phosphoric acid, which is then dried and
granulated to produce a significantly higher concentration of nutrients
than is possible with those products based on normal superphosphate.
Mixed fertilizers produced from phosphoric acid are generally manufac-
tured in the same complex where the phosphoric acid is produced largely
in Florida, but with significant production in North Carolina, the New
Orleans area, and the upper Midwest.
There is also a limited but growing use of liquid Tiiixed fertilizers,
in which the nutrients exist either in dissolved form in clear solutions,
or as stable suspensions of solid particles. These are often produced in
a two-step operation, in which a base solution of ammonium phosphate is
produced in a large central "hot-mix" plant. The finished product contain-
ing additional quantities of nitrogen and potash is then produced in smaller
"cold-mix" plants located close to the marketplace.
e. Distribution and Blending
Major changes have taken place in the mode of distribution, principally
through the emergence of "bulk blending" stations as the principal means
of marketing fertilizer materials.
Until the emergence of bulk blending in the early 1960's, traditional
distribution of fertilizer involved the movement of bagged mixed fertilizers,
from medium-sized production plants producing between 25,000 and 200,000
tons per year of mixed fertilizer, to farm buyers, through general retail
farm supply organizations. Thus, the farmer purchased through such outlets
as feed and seed stores, grain elevators, etc. Single nutrient materials,
such as ammonium sulfate and muriate of potash, were used in addition and
were also handled in bags through the same outlets.
12
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However, in the early 1960's, the advantage of bulk handling of ferti-
lizers became apparent and the emergence of bulk blending developed quickly.
In bulk blending, a few basic high analysis materials containing single
nutrients (or, in the case of ammonium phosphates, both nitrogen and phos-
phorus) are shipped in bulk form to retail bulk blending units. Here they
are combined physically in mixtures suited to the particular needs of indi-
vidual farmers. To avoid segregation during mixing and handling, they are
generally in granular form of relatively uniform size. Simple physical
mixing operations take place and the material is generally applied in
bulk through the use of broadcast spreading trucks. Thus, at no point in
the distribution chain are the materials handled in any but bulk form.
With the availability of a wide variety of blends of the three nutri-
ents at the retailing station, the demand for basic products shifted from
the chemically mixed fertilizer materials to major blending materials such
as ammonium nitrate, triple superphosphate, diammonium phosphate, and
muriate of potash.
As this mode of distribution developed, many of the major manufacturers
developed their own organization of bulk blending stations, thus emerging
as the direct seller to the farmer. A typical large fertilizer organiza-
tion might develop a chain of 100 to 200 such bulk blending stations. These
would typically handle from 1,000 to 5,000 tons of material per year and
generally sell within a radius of 15 miles.
Bulk blending, together with liquid mixed fertilizers, has displaced
a great portion of former quantities of chemically mixed fertilizers. Never-
theless, substantial volumes of mixed fertilizers are in continued use,
particularly of the higher grades, such as 10-20-10 or 15-15-15.
2. Integration
The U.S. fertilizer industry is characterized by a substantial amount
of integration, both vertical and horizontal. Most basic producers .of raw
materials, such as phosphate rock, potash, and ammonia, are also involved
in chemical upgrading to finished fertilizer products, and in many instances
have well-developed distribution and marketing organizations that have
direct retail contact with the ultimate farmer/consumer. Many companies
are basic manufacturers of more than one nutrient raw material. The degree
of horizontal integration of the major companies is indicated in Table III-l.
i
There has been considerable retrenchment of vertical integration
extending to retail outlets. During the expansion period of the mid-1960's,
many basic fertilizer producers developed programs for retailing major
volumes of their product through wholly owned or controlled retail outlets.
However, most major companies were unable to operate retailing operations
profitably, and many subsequently disposed of these outlets. However,
companies which are still active at the retail level include Agrico, Allied
Chemical, W.R. Grace, and The First Mississippi Corporation. Farmland
Industries and CF Industries, which are both major farm cooperative organ-
izations, of course have a built-in retail system through their county farm
co-ops, which are ultimately the owners of the parent industries.
13
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TABLE III-l
INTEGRATION OF LEADING AMMONIA PRODUCERS
Ammonia Phosphate Rock Phosphoric Acid Potash1*
(thousand tons N) (thousand tons) (thousand tons PO^S^ (thousand tons K_0)
CF Industries 1,069 1 1,250 440
Farmland Industries 1,081 - 455
Agrico 1,030 9,100 735
Allied Chemical 979 - 160
Collier Carbon 628 - 14
Chevron 621
Mississippi Chemical 602 - 200
Amoco 588 - ~
Vistron 470
U.S. Steel 466 2,800 265
IMC 278 12,500 750 2,710
Occidental 177 5,500 610
Mobil - 4,500 125
Texas Gulf - 4,000 685 550
American Cyanamid 278 3,000 263
W.R. Grace 358 2,300 325
Beker 244 2,300 565
Gardinier 268 2,000 590
Total of Above Companies 9,1373 48,000 6,992 3,700
(% of Capacity) 59% 78% 77% 33%
Total of Top Ten Companies 7,5343 48,000 6,814 9,322
(% of Capacity) 49% 78% 75% 84%
Total Capacity 15,524 61,884 9,044 11,058
Source: Derived from TVA listing.
1 Long-term contract with IMC .
2 Has tolling arrangement for roughly 35% of Freeport capacity.
Excludes duPont, with capacity of 636, because it does not serve the fertilizer industries.
It is included in Total Capacity.
4 Includes Canada.
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3. Energy Use
Aside from the manufacture of ammonia and mineral raw materials, the
use of energy by the fertilizer industry is relatively small compared to
other industries in this study. Energy use in fertilizer manufacture in
1973 is provided in Table III-2. Energy used to produce fertilizer pro-
ducts was 52 x 1012 Btu's, almost half of which was in the form of electric
power. This amount excludes the energy to produce the raw materials,
ammonia (covered in a separate report), phosphate rock, potash and sulfur.
These raw materials consumed 574 x 1012 Btu's, indicating that the fertil-
izer included in this discussion represented only 8% of the total energy
used by the industry. Energy use includes that used in the manufacture
of fertilizers only and excludes energy used to produce the products for
non-fertilizer uses.
For the most part, the fuels used are for generating steam and for
drying furnaces. Electricity is used to operate motors, compressors, pumps,
materials handling equipment, and grinding equipment.
4. Plant Characteristics
Of primary importance in this report are nitric acid and granular mixed
fertilizer plants. Therefore, only these two types of plants are discussed.
a. Nitric Acid
There are approximately 125 nitric acid plants in operation in the
United States. Because nitric acid is produced from ammonia, most nitric
acid plants are located adjacent to ammonia plants within an overall nitrogen
products complex. However, since the transport of ammonia is not difficult,
there are a number of nitric acid plants which are not associated with
ammonia manufacturing facilities and receive their raw material by rail,
water, or pipeline transport.
There is a fairly wide spectrum of plant sizes within the nitric acid
industry. There are some 24 plants with capacities below 100 tons per day,
and the remaining units are fairly evenly distributed within the size range
of 100-500 tons per day. Approximately 45% of the capacity consists of
plants- in excess of 300 tons per day, with some plants running as large as
500 tons per day. \
b. Mixed Fertilizers
Prior to 1960 there were approximately 200 mixed-fertilizer plants
located throughout the country, often in association with normal superphos-
phate plants. These produced low-analysis mixed fertilizers based on the
ammoniation of normal superphosphate. As economics has favored fertilizers
more concentrated than could be made using normal superphosphate, a number
of these plants have been shut down or converted to make higher-analysis
fertilizer based on phosphoric acid.
15
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TABLE III-2
ENERGY USE IN FERTILIZER MANUFACTURE - 1973
Fuel
Power
Raw Materials
Ammonia
Phosphate Rock
Potash
Sulfur
Sub-Total
1012 Btu
491.7
15.9
9.6
29.0
546.2
Total
10 kWh
584
1,643
379
76
2,682
1012 Btu1
6.1
17.3
4.0
0.8
28.2
(1Q12 Btu)
497.8
33.2
13.6
29.8
574.4
79
5
2
5
92
Fertilizers
Urea
Ammonium Nitrate
Phosphoric Acid
Triple Superphosphate
Diammonium Phosphate
Normal Superphosphate
Mixed Fertilizers
Sub-Total
7.7
9.5
0.0
1.4
4.6
0.0
5.0
28.2
460
390
647
110
286
65
350
2,308
4.8
4.1
6.8
1.2
3.0
0.7
3.7
24.2
12.5
13.6
6.8
2.6
7.6
0.7
8.7
2
2
1
0
1
0
1
52.4
Total
574.4
4,990
52.4
626.8
100
1 At 10,500 Btu/kWh.
Source: Arthur D. Little, Inc., "Economic Impact of Shortages on the Fertilizer Industry" report
to the Federal Energy Administration, January, 1975.
-------
There are about 160 of these old plants still operating, though prob-
ably no more than 40-50 of them are still based on normal superphosphate.
These typically have annual production ranging from 20,000 to over 100,000
tons per year, with 50,000 to 60,000 tons being the average. Additionally,
there are 25 to 30 more modern fertilizer plants based on phosphoric acid,
with capacities ranging from 100,000 to 500,000 tons per year. These
involve the drying and granulation of mixed fertilizer formulations based
on additions to phosphoric acid.
An up-to-date listing of granulation plants is not available. A list
was prepared in 1973 by the Potash Institute of North America, and appears
as Table III-3. It cannot be determined from this listing, however, which
of these plants are still operating as granulation plants or which are
associated with operating superphosphate or sulfuric acid plants.
B. OUTLOOK
1. Nitrogen Fertilizers
The rate of growth in the consumption of fertilizer nitrogen in the
United States has dropped off significantly over that which prevailed for
the years prior to 1970. We have summarized prior consumption data in
Table III-4, together with our estimates of the U.S. consumption in 1980
and 1985.
The annual rate of growth for the period 1960 to 1970 averaged 10.5%
per year. This dropped off significantly following 1970. For the four-
year period from 1970 to 1974, the average annual growth was 5.3%. In 1975,
consumption declined 6% from the previous year. The decline in the rate
of growth of nitrogen consumption in recent years may in part be due to a
saturation in the market after many years of very high growth. However,
more important reasons were worldwide shortages of nitrogen fertilizers
and very significant price increases.
The recent performance of nitrogen fertilizer consumption casts some
doubt on future growth rates. However, there is a fundamental need for
increasing quantities, and we believe that an average growth rate of 6%
per year through 1985 is realistic. Therefore, we have included in Table
III-4 our estimates of nitrogen fertilizer consumption in 1980 and 1985,
on the basis of a 6% annual(growth rate for the next ten years.
On the basis of these consumption figures, an additional 7.7 million
tons of nitrogen will be needed in 1985, compared with that consumed in
1975. This is roughly equivalent to 28 of the 1,000-ton-per-day ammonia
plants. A number of these are under construction; however, additional pro-
jects will have to be initiated to meet the demand which we expect to
develop by the mid-19801s.
17
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TABLE III-3
GRANULATION PLANTS IN UNITED STATES
Alabama
U.S.S. Agri. Chem.-Charokee
Swift-Birmingham
Goldkist-Hanceville
Miss. Chemical-Decatur
Centrala-Dempolis
Arkansas
Agr ic o-Walnu t
Arkla-Helena
Olin-North Little Rock
California
Chevron-Richmond
Occidental Chem-Lathrop
Colier Carbon & Chem-Nichols
Swift-L.A.
Valley Nitrogen-Helen
Valley Nitrogen-Elison
Florida
Kaiser-Tampa
Swift-Winter Haven
Georgia
Columbus Nitrogen-Moultrie Macon
W.R. Grace-Colquitt (New Albany)
I.M.C.-Americus, Augusta
Kaiser-Bainbridge
Royster-Macon, Athens (2)
Swift-Albany,Savannah
U.S.S. Agri Chem.-Albany, Columbus
Pelham Phosphates-Pelham
Goldkist-Cordele, Goldkist
So. States Phosphate
Illinois
Borden Chemical-Streator
U.S.S. Agri Chem.-E. St. Louis
Chicago Hgts.
Allerton Supply-Allerton
Perkinson Co.-Decature
Effingham Equity-Eff inghaip
A.B. Cheis'inan, Inc.-Meredosia
Indiana
Texaco-Butler, Peru
U.S.S. Ag. Chem.-Jeffersonville
Kova Fert.-Greensburg
IFBCA-Indianapolis, Columbia
Iowa
Arco-Ft. Madison
Chevron-Ft. Madison
Kentucky
Royster
Texaco-Louis.&Nashville
Borden-Russellville
Bluegrass Plant Fd.-Cynthiana
Burleybelt Pert.-Lexington
Ohio Valley Fert.-Maysville
So. States-Louisville, Owensboro,
Russelville
Louisiana
Agrico-Donaldsonville
Swift-Shreveport
18
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TABLE III-3
GRANULATION PLANTS IN UNITED STATES (Cont.)
Maine
Brockville Chem.-Preque Isle
Agway-Detroit
Maryland
Agrico-Baltimere
W.R. Grace Co.-Baltimore
Kerr McGee-Baltimore, Cambridge
Swift-Baltimore
U.S.S. Ag Chem.-Baltimore
Miller Chem.&Fort.-Whiteford
Lebanon Chem. Corp.-Baltimore
W.D. Tillghman-Salisbury
Lebanon Chem.-Baltimore
So. States-Baltimore
Mass.
Coranco-Lowell
Michigan
Agr ic o-Sag inaw
Borden Chem-Saginaw, Holland
Riga (3)
Minnesota
Howe, Inc.-Minneapolis
Rochester Fert.-Rochester
Mississippi '
Royster-Jackson
Swift-Jackson
Miss. Chemical-Yazoo City Pascaquola
Missouri
Farmland Chem.-Joplin
Missouri Farmers Assn.-Palymra,
Springs
Nebraska
Federal-Omaha
New Jersey
Texaco-Cranbury
Chamberlain & Barclay-Cranbury
Star Fish & Bone-Bridgton
Agway-Yardville
New York
Agrico-Burralo
Royster
Agway-Albany, Batavia, Big Flats,
Lyons, Canastock
N. Carolina
Agrico-Greensboro
Borden Chem.-Kinston (2)
Swift-Wilmington (?)
W.R. Grace-Wilmington
I.M.C.-Winston Salem
Kaiser-Wilmington
Kerr McGee-Williamston
Royster-Wilmington, Charlotte
U.S.S. Ag. Chem.-Greensboro
Wilmington Fert.-Wilmington
Weaver Fert.-Winston Salem
Pearsail & Co.-Wilmington
New Barn Oil & Fert.-New Barn
Farmers Chem-Tunis
Ohio
Swift-Orrville
Agrico-Cairo, Wash. Ct. House
W.R. Grace-Findlay, Columbus (2) Alliance
Plant Life Services-Marion
F ed eral-C olumbus
Kerr McGee-Fostoria
Landmark-Mt. Gilead
Scotts-Marysville
Marion Plant Life-Marion
19
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TABLE III-3
GRANULATION PLANTS IN UNITED STATES (Cont.)
Pennsylvania
Kerr McGee-Philadelphia
Reichard-Allentown
Lebanon Chem.-Lebanon, Allentown
Miller Chemical-Hanover
Agway-York, Kittanning
So. Carolina
W.R. Grace Co.-Charleston
I.M.C.-Hartsville
Kerr McGee-Florence-Jericho
Swift-Columbia (Charleston?)
Tennessee
Agric o-Memphis
Texaco-Humboldt,Nashville
W.R. Grace-Memphis
U.S.S. Ag.Chem.-Nashville
Memphis
Swift-Memphis
Tenn. Farmers' Coop-Lavoigne,
Jackson
Texas
Texas Farm Products
Nipak, Inc.-Littlefield-Kerens
Swift & Co.-Houston
Borden Chem.-Texas City
Occidental Chem.-Houston,
Plainview
Farmer s Fer t.-Texarkana
Red Barn-Freeport
Texas Farm Prod.-Nacogdoches
Virginia
Borden Chemical-Norfolk (2)
Danville
Royster-Norfolk
Swift-Norfolk
Charles Priddy Co.-Norfolk
Richmond Guano-Richmond
The Vance Co.-Chilhowis
So. States-Chesapeake, Va., Richmond
Wisconsin
Federal Chem.-White Water
Royster-Madison
Koos-Kenosha
F.S. Services-Prairie du Chien
Source: Prepared by Potash Institute of North America - May 1973
20
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TABLE III-4
FERTILIZER NITROGEN CONSUMPTION
(000 tons N)
1960 2,738
1965 4,639
1970 7,459
1971 8,134
1972 8,016
1973 8,339
1974 9,157
1975 8,608
1980 (@6%/yr) 12,254
1985 (@6%/yr) 16,400
Source: U.S. Department of Agriculture and
Arthur D. Little, Inc, estimates.
Increasing attention is being given to solid urea as the most attrac-
tive nitrogen fertilizer product. Recent analyses indicate that urea can
be as competitive as anhydrous ammonia, in terms of price per unit of
nitrogen applied to the ground. A number of companies are erecting addi-
tional urea production facilities and emphasizing its use as a fertilizer
material. Therefore, solid urea's share of the total fertilizer nitrogen
market will likely increase significantly. This will largely be at the
expense of ammonium nitrate, and this tendency will also limit further
growth in the use of anhydrous ammonia as a direct application fertilizer
material, on a percentage-of-market basis.
It is likely that the shortage of natural gas will limit the number
of additional ammonia plants that can be constructed in the United States,
at least in the short term. Therefore, additional nitrogen required may
be supplied from plants outside the United States. A number of plants
under construction in Canada, Mexico, Venezuela, and Trinidad may have
surplus capacity most logically suited for the U.S. market. These would
be the primary off-shore sources if import requirements do develop. However,
more distant sources, such as the USSR, North Africa, and the Arabian Gulf,
may also be potential suppliers.
2. Nitric Acid
Nitric acid finds its greatest use (about 75%) in the production of
ammonium nitrate, which is used primarily for fertilizers, but substantial
quantities are also used for explosives. Additional smaller quantities of
nitric acid are used for the production of nitric phosphate fertilizers,
munitions, the manufacture of several organic chemical intermediates, and
for stainless steel pickling. Production for recent years, based on Depart-
ment of Commerce figures, is shown in Table III-5.
21
-------
TABLE III-5
NITRIC ACID PRODUCTION
(thousand tons of 100% nitric acid)
Year Production
1966 5,514
1967 6,463
1968 6.992
1969 7,223
1970 7,603
1971 7,638
1972 7,981
1973 7,690
1974 8,192
1975 6,964 (based on 9 months production)
The growth in the period 1966-1974 represented approximately 5% per
year annual increase. The substantial drop in 1975 was probably due to
the drop in industrial activity during the recession, together with an
approximate 6% decline in nitrogen fertilizer use.
The future outlook in demand would suggest a somewhat reduced annual
rate of growth. Ammonium nitrate's displacement of dynamite as an above-
ground blasting agent is essentially complete, and further growth in this
direction will probably proceed at the same general rate of increase as
the use of explosives. In the fertilizer area, major attention is being
focused on urea as the primary solid nitrogen material of the future, and
it is doubtful that actual volumes of ammonium nitrate used in agriculture
will increase substantially. For this reason, a 4% annual growth rate
through the 1980's is an appropriate forecast for nitric acid. On this
basis, and using 1974 production as the base year, future demand is esti-
mated as shown in Table III-6.
TABLE II1-6
FUTURE NITRIC ACID DEMAND
(thousand tons of 100% nitric acid)
Year Production
1974 8,191
1980 10,360
1985 12,600
22
-------
U.S. nitric acid capacity was estimated in 1975 at 9.7 million tons
of 100% nitric acid. There are approximately 125 nitric acid plants at
84 locations in the United States. It is possible that effective capacity
may be significantly below this figure, because some plants have been shut
down or even dismantled. Nevertheless, the total figures do suggest that
there is significant excess capacity. All but a few of these plants use
a pressure process.
Assuming effective capacity may be in the neighborhood of 9 million
tons per year, an additional 1.4 million tons capacity will be needed by
1980, and a further 2.2 million tons of capacity by 1985.
One factor that could affect future production of nitric acid is the
availability of ammonia. However, even if domestic ammonia production
increases are limited by the gas situation, imported ammonia should be
available to meet additional nitric acid requirements.
3. Mixed Fertilizers
During the depressed conditions of the fertilizer industry in the late
1960's and early 1970's, many of the granular mixed fertilizer plants
throughout the country were closed down. This was a result of a decline
in the use of particular types of fertilizers. Many companies had a dozen
or so plants, each of which was operating at well below capacity. Thus,
a consolidation occurred, with the less efficient or most poorly located
plants being closed. Now the use of complete mixed fertilizers has stabi-
lized, and it is likely that those plants still remaining will continue to
operate. A number of them are being renovated so that they will be capable
of making higher-analysis products by using phosphoric acid rather than
normal superphosphate.
There is some question as to whether it may not be preferable to pro-
duce such high-analysis mixed fertilizers in large plants, rather than in
small plants near the markets. Such a decision would hinge on many factors,
and each company will have its own decision to make. Nonetheless, if
significant costs must be incurred in adding pollution control equipment
or in other renovations, it could result in the closing of many of the old
plants.
23
-------
IV. COMPARISON OF CURRENT AND ALTERNATIVE PROCESSES
A. REASONS FOR CHOOSING OPTIONS TO BE ANALYZED IN DEPTH
The major use of energy in the fertilizer industry sector is as a feed-
stock and fuel for ammonia production, which in this study is analyzed
separately. In addition, the phosphorus-phosphoric acid industry is also
considered separately. In the remainder of the fertilizer industry, we
uncovered two areas having potential impact on energy conservation and
pollution control:
Air pollution control in nitric acid plants, and
Conversion to fuel oil for drying in mixed fertilizer plants
equipped with bag filters.
1. Air Pollution Control in Nitric Acid Plants
The principal way of reducing nitrogen oxide emissions from a nitric
acid plant is the catalytic reduction of the oxides to molecular nitrogen and
oxygen. The process requires considerable investment and is energy intensive.
Furthermore, the process requires that the major energy source be natural gas,
which is in short supply both in the nation and to specific nitric acid plants.
For these reasons, we have reviewed alternatives to the basic air pollution
process to determine whether other methods are available that will not require
natural gas, and to determine the costs of such options. Options reviewed in
detail are:
Molecular Sieve,
Grande Paroisse,
CDL/Vitok, and
Masar.
2. Conversion to Fuel Oil for Drying in Mixed Fertilizer Plants
Equipped with Bag Filters
We have chosen the two options of upgrading dryer burner equipment/
technique and installation of a scrubber, because these are the only two
viable control options for the ammoniation granulation plants that now use bag
filters rather than scrubbers to control dryer and cooler emissions. '
24
-------
Neither of the options considered here are, strictly speaking,
process changes. The changes under consideration relate only to the air
pollution control options. The bases for the control options are
illustrated in Figure IV-1, which shows a simple bag filter and a plate-
type scrubber. The bag filter has the advantages of:
generating no wastewater.
allowing easy recycle of product, and
greater efficiency of particulate control (see Figure IV-2).
On the other hand, it has the disadvantages of being attacked by acid mist and
being easily clogged unless considerable attention is given to its care during
plant operation. This is particularly true when hygroscopic dusts (such as
fertilizer) are present in the gas stream being filtered. To avoid condensa-
tion, the gas temperature must be maintained about 70°F above the dewpoint of
the highest boiling gaseous contaminant or reaction product. Consideration
must also be given to the products of gas phase reactions in the dryer. For
example, solid ammonium chloride may be formed through the reaction of gaseous
ammonia with hydrogen chloride (formed by the reaction of sulfuric acid with
potash). One producer reported that it took nearly a year to optimize
operation conditions for use of the bag filter.
B. COMPARISONS OF CURRENT AND ALTERNATIVE PROCESSES
1. Nitric Acid
a. Base Line Technology for Nitric Acid Manufacture
(1) Nitric Acid Process
Nitric acid is an important material in the manufacture of fertilizer-
grade ammonium nitrate and explosives. The acid is produced by oxidation of
ammonia, usually under high pressure and temperature over a platinum catalyst,
forming nitric oxide (NO). The gaseous products from the reactor and oxygen,
are cooled to form N02, and are sent to an absorption tower to form the acid
product. The process forms an acid of approximately 60 - 65% strength, which
is sufficient for ammonium nitrate production, and may be upgraded to 99%
strength by one of several concentration processes. Both the ammonia reactor
and the absorption tower are operated under high pressure, which favors heavy
production of NO and N02 with minimum equipment. Oxidation of ammonia and
final reduction of tail gas compounds are highly exothermic reactions which
produce the heat and energy needed to satisfy demands in other parts of the
plant. The flow diagram of a typical 300 tpd nitric acid plant utilizing the
pressure process is given in Figure IV-3, which shows catalytic reduction
used for NOX abatement. The process change considered here is the NOX abate-
ment system. The base case is the nitric acid industry with no abatement.
25
-------
GAS
IN
.STACK
FABRIC FILTERS
RECOVERED DUST
SCREW CONVEYOR
BAG HOUSE COLLECTOR
STACK
PLATE TYPE SCRUBBER
Source: Tennessee Valley Authority
ENTRAPMENT
COLLECTOR
EFFLUENT
Figure IV-1. Bag House Collector and Plate Type Scrubber
26
-------
99.99
g-
c
OJ
'o
it
0>
o
o
O
to
Source: Towards Cleaner Air - A Review of Britain's Achievements. Central Office of Information for the
British Overseas Trade Board, London, 1973.
Figure IV-2. Partlculate Collection Efficiencies for Various Types of Control Equipment
-------
NATURAL CATALYST TT AMMONIA
GAS V \OXIDI2ER
Flow, (Ib/hr)
Temperature, (°F)
Pressure, (psig)
NH3, (Vol %)
NO, (Vol %)
N02, (Vol %)
O2, (Vol %)
H20, (Vol %)
HN03, (Wt%)
H2),(Wt%)
N, (Vol
2,
0,
10
Tail Gas
103,000
85
92
0.10
0.15
3.0
0.6
96.15
(Vol
Stack Effluent
106,500
450
0
0.10
Nil
Nil
3.8
94.2
2.0
Source: Atmospheric Emissions from Nitric Acid Manufacturing Processes,
USHEW, Publication No. 999-AP-27, 1966.
Figure IV-3.
Flow Diagram of a Typical 300-Ton-Per-Day Nitric Acid
Plant Utilizing the Pressure Process
28
-------
The cost of making nitric acid is largely dependent on the price of the
ammonia raw material. Using a figure of $100 per ton, ammonia represents
over half the cost of manufacture, including a 20% margin to cover income
taxes, profits, and general selling and administrative expenses. A detailed
cost estimate is provided in Table IV-1. Fixed investment is estimated to
be $5.5 million for a 300 tpd plant, or $54 per annual ton.
(2) Emissions from Nitric Acid Plant
The main source of atmospheric emissions from the manufacture of nitric
acid is the absorption tower tail gas, which contains unabsorbed oxides of
nitrogen. These oxides are largely in the form of nitric oxide and nitrogen
dioxide. In addition, trace amounts of nitric acid mist are present in the
gases as they leave the absorption system. In the pressure process, the gases
are reheated for power recovery purposes and are discharged to the atmosphere
at 400 - 500°F; any nitric acid mist present is then changed to its vapor
state to discharge into the atmosphere. In the atmospheric system, tail gases
discharged to the atmosphere are cold, and therefore, any entrained particles
of nitric acid in this gas stream would appear as a mist. The quantity
depends on the extent of entrainment and the efficiency of entrainment
separators.
The tail gas is reddish-brown; the intensity of the color depends on the
concentration of nitrogen dioxide present. The concentrations of 0.13% to
0.19% and higher by volume of nitrogen dioxide produce a definite color in the
exit plume. Effluent gases containing less than 0.03% nitrogen dioxide are
essentially colorless. (Nitric oxide, as distinguished from nitrogen dioxide,
is colorless.)
Nitrogen oxide emissions from nitric acid plants are given in Table IV-2.
The tail gas from the pressure process iray be considered to have the average
composition given in Table IV-3. Total NOX emissions from a nitric acid plant
are shown in Figure IV-4.
Small amounts of acid mist may be present in the emissions from some
nitric acid plants. A small quantity of entrained acid is generally present
in the gases leaving the absorption system. In the pressure process, the tail
gases are reheated and expanded before being released to the atmosphere at
400-500°F; this treatment results in vaporization of any traces of acid mist
that may have been presentiin the gases from the absorber. Emissions from
acid storage tanks may occur during tank-filling operations. The gases
displaced are equal in volume to the quantity of acid added to the tank.
(3) Emission Control Standard
In the United States, the limits on nitric oxide and nitrogen dioxide
(commonly considered together as NOX) emitted from nitric acid plants are
3 Ib/ton of 100% acid for new plants (federal standard) and, on the average,
5.5 Ib/ton of 100% acid for old plants (state standards). This is equivalent
to approximately 200 ppm and 400 ppm, respectively, by volume in the tail gas.
29
-------
TABLE IV-1
PRODUCTION COSTS
Product: Nitric Acid
Annual Capacity: 102,000 Tons
Location:
LouIsinna
Fixed Investment;: $5,500,000
Annual Production: 102,000 Tons
VARIABLE COSTS
Raw Materials
Ammonia
Energy
Natural Gas
Energy Credits
Steam
Water
Process (Consumption)
Cooling (Circulating Rate)
Direct Operating Labor (Wages)
Direct Supervisory Wages
Maintenance
Labor Overhead
Catalyst
Chemicals & Operating Supplies
FIXED COSTS
Plant Overhead
Local Taxes and Insurance
Depreciation
TOTAL PRODUCTION COSTS
Return on Investment (pre-tax)
POLLUTION CONTROL
TOTAL
Units Used in
Costing or
Annual Cost
Basis
8 men
It foremen
1 superin-
tendant
5% of Investm(
30% of Operatit
707, of Operati
2% of Investn
11 years
20% of Fixed I
$/Unit
SlOO/ton
$2/MCF
$3/103 Ib
$0.75/103 gal
$0.03/103 gal
J12,700/yr
$18,000/yr
$25,000/yr
nt
g Labor & Super
$185/oz
ng Labor & Supe
ent
nvestment
Units Consumed
per Ton of
Product
0.292 ton
1.6 MCF
700 Ib
280 gal
18,300 gal
0.00802 oz
$/ADT of
Product
29.20
3.20
(2.10)
0.21
0.55
1.00
0.95
2.70
0.59
1.48
.50
1.37
1.08
4.90
45.70
10.78
56.48
30
-------
TABLE IV-2
NITROGEN OXIDE EMISSIONS FROM NITRIC ACID PLANTS
Control Emission NO?3
Type of Control Efficiency Ib/ton Acid Kg/MT Acid
(%)
Weak Acid
Uncontrolled 0 50-55 25-27.5
Catalytic Combustor 78-97 2-7 1-3.5
(natural gas fired)
Catalytic Combustor 97-99.8 0-1.5 0-0.75
(hydrogen fired)
Catalytic Combustor 98-98.5 0.8-1.1 0.4-0.55
(75% hydrogen
(25% natural gas)
High-Strength Acid 0.2-5.0 0.1-2.5
aBased on 100 % acid production
Source: Compilation of Air Pollution Emission Factors, Second Edition,
US EPA Publication No. AP42, March 1975.
TABLE IV-3
AVERAGE COMPOSITION OF TAIL GAS FROM THE PRESSURE PROCESS
Total Nitrogen Oxide (NO + N02) 0.3%
Oxygen 3.0%
H20 0.7%
N , etc. Balance
Source: Atmospheric Emissions from Nitric Acid Manufacturing
Processes, USHEW, Publication No. 999-AP-27, 1966.
31
-------
1,200
1,000
Q ,_
UJ 3
I- 9
0 ? 800
_i -o
51
X 5
LLJ O
«z
O LU
< 2
BASED ON 85 scfm OF EFFLUENT
PER DAILY TON OF ACID
400
200
0 100 200 300 400
PRODUCTION OF NITRIC ACID, tons/day
(100% HN03 BASIS)
Source: "Atmospheric Emissions from Nitric Acid Manufacturing Processes,"
USHEW, Publication No. 999-AP-27, 1966.
Figure IV-4. Total NOX (Calculated as N02)/Hour vs Daily
Production of Nitric Acid
Adoption of air pollution control is a recent practice in the nitric
acid industry. The process change considered in this study is the
application of alternative NOX abatement systems. Therefore, the base
case is considered as a nitric acid plant without NOX abatement.
b. NOX Abatement Technology
In this section, we consider the following NOX abatement systems:
Catalytic Reduction Method,
Molecular Sieve Process,
Extended Water Absorption or Grande Paroisse Process,
e CDL/Vitok Process,
Masar Process, and
Alkali Scrubbing Process.
In addition to the above processes, there are the SABAR process, Chemico
Hycon process, and several European processes.
32
-------
(1) Catalytic Reduction Process
In the catalytic reduction process, the residual tail gas from the
absorber, essentially nitrogen, is demisted and then preheated with steam.
The hot tail gas is then further heated by passing it through the shell side
of the heat exchanger train utilized to cool the hot process gas.
Before being introduced into the hot gas expander, the reheated tail gas
is passed through a combustor that contains catalyst. The oxides of nitrogen
are reduced to N2 and 62 in the combustor. Natural gas or hydrogen is used as
the fuel in the combustor. The flow diagram is shown in Figure IV-3. Hydrogen
or natural gas, or a mixture of the two, are used as fuels. The stack effluent
is usually clear and colorless, indicating reduction of all nitrogen dioxide
to nitric oxide, at least to less than 0.03% by volume. In most cases there
is substantial, if not total, removal of oxygen by combustion with the fuel.
Current Status of the Catalytic Reduction Process - The catalytic
process is well established and has been installed on several nitric
acid plants. It can also be retrofitted on an existing plant if it
uses a pressure process and practices power recovery. If the plant
uses a low-pressure process, the capital cost of the catalytic
reduction process will be too high. If the plant operates at high
pressure and does not practice power recovery, the operating costs
of the NOX abatement will be too high, because there will be no use
for the steam, and the plant may adopt an alternate NOX abatement
device or may shut down.
Effluent Control - The only flow stream from the combustor is the
tail gas. If the combustor temperature is maintained according to
specifications, the exhaust gases will meet the stationary source
standards. Maintenance of operating conditions is also important to
prevent carry-over of the catalyst, overheating of the catalyst, etc.
Economic Factors - The estimated capital cost and the operating
cost of the catalytic process for NOX abatement are given in
Table IV-4. Investment cost is high, as are the investment-
related operating costs. Charges for catalyst and fuel are also
significant, although the fuel costs are largely offset by a
steam credit if the steam can be utilized.
Energy Requirements - The energy requirements for a catalytic
process for NOX abatement are given in Table IV-5, which indicates
that method is an energy intensive process. Particularly critical
is the fact that this energy must be in the form of natural gas,
which is in short supply.
Technical Considerations - A significant amount of fuel is used in
the catalytic reduction process. A major portion of the heating
value of the fuel is recoverable in the form of steam. Thus, there
is a net export of steam from such a plant, and it may be possible
to use the heating value of the steam in other operations at the
same location. Attention must be paid to the uses of steam.
33
-------
TABLE IV-4
CAPITAL AND OPERATING COSTS FOR DIFFERENT NOX
ABATEMENT SYSTEMS IN A 300 TPD NITRIC ACID PLANT
Catalyst Molecular Grande CDL/
Reduction Sieve Paroisse Vitok
Masar
1,384,000 1,200,000 1,000,000 575,000 663,000
360
2,200
315
2,200
4,400
77,800
15,833)
187,590)
128
360
2,200
315
2,200
4,400
45,600
500
7,330
250
6,120
322
360
2,200
315
2,200
4,400
300
4,420
90
360
2,200
315
.2,200
4,400
1,020
14,980
715
17,500
265
360
2,200
540
3,775
,5,975
1,310
32,070
20
Capital Investment,1 ($)
Operating Costs
Operating Labor, (hr/yr)
($/yr)
Maintenance Labor,
($/yr)
Labor Overhead (incl. fringe
benefits & supervision, $/yr)
Catalyst or Molecular Sieve
Cooling Water, (gpm)
($/yr)
Steam, (Ib/hr)
($/yr credit)
Electricity,(kW)
($/yr)
Boiler Feed Water, (gpm)
($/yr)
Fuel, (106 Btu/hr)
($/yr)
Nitric Acid, (tpd)
($/yr)
Urea, tpd
($/yr)
Ammonium Nitrate, (tpd)
($/yr)
Depreciation (11-yr life)
Return on Investment (@ 20%)
Taxes & Insurance, (@ 2%)
Total Annual Cost, ($/yr)
Annual Cost, ($/ton)
Investment estimates exclude interest during construction, owners expenses,' and
land costs.
Includes credit for 0.0017 tons of urea/ton of nitric acid produced present in
the spent solution (D.SITPD).
20,890
35
12,850
28.5
465,120
52,550
2.0
32,640
(6.6)
14,690 43,250 3,260
(6.0) (6.0) (5.28)
(112,200) (102,000)(102,000) (89,760)
1.372
74,528
1.25
(42,500)
125,900
276,800
27,700
628,270
6.16
109,090
240,000
24,000
413,930
4.06
90,910 52,300 60,300
200,000 115,000 132,600
20,000 11,500 13,260
236,780 161,330 195,708
2.32 1.58 1.92
Source: Arthur D. Little, Inc. estimates.
34
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TABLE IV-5
ENERGY REQUIREMENTS IN NOX ABATEMENT SYSTEMS FOR
A 300 TPD NITRIC ACID PLANT
(109 Btu/Yr)
Steam (Credit)
Electrical
Natural Gas
Oil
Basic Nitric
Acid Plant
(71.4)
-
163.2
Catalytic
Reduction
(129.20)
10.97
232.56
Molecular
Sieve
2.04
27.59
_
Grande
Paroisse
-
7.71
_
CDL/
Vitok
5.83
22.71
_
Masar
10.69
1.71
_
91.8
114.33
16.32
45.95
7.71
28.54 12.40
Source: Arthur D. Little, Inc. estimates.
TABLE IV-6
BASIS FOR TABLES IV-4 AND IV-5
(Plant Capacity 19 300 tpd and 102,000 tons/yr)
(March 1975 Dollars, ENR Index - 2,126)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
Operating Labor @
Maintenance Labor @
Overhead @
Cooling Water @
Boiler Feeduater @
Natural Gas 9
Oil 9
Depreciation @
Return on Investment
Taxes and Insurance
Nitric Acid
Urea
Ammonium Nitrate
1 kWh - 10,500 Btu
Electricity
$6.1/hr
$7.0/hr
100% of labor (Including fringe benefits
and supervision)
$0.03/1,000 gal
$0.75/1,000 gal
$2.00/106 Btu
$2.00/106 Btu
11 yr straight line
@ 20% of capital cost
8 22 of capital cost
9 $50/ton
@ $160/ton
@ SlOO/ton
9 $0.02/kWh
35
-------
The requirement of catalyst use may be solved with proper atten-
dance. The service life of the catalyst, contamination or over-
heating, may present problems if operating conditions are not
properly maintained.
(2) Molecular Sieve Method
This method is based on the principles of absorption, oxidation, and
regeneration of the molecular sieve. An oil-fired heater is used to provide
heat for regeneration. The process has high efficiency for removal of NOX
gases. The NO outlet concentration is generally below 50 ppm.
The pressure drop in the molecular sieve is significant, and averages
5 psi.
Current Status of Process - The process has been applied to three
plants in the United States having capacities of 55 tpd and higher.
The process has operated successfully in controlling the NOX
emissions.
Effluent Control - The only flow stream from the molecular sieve
process is tail gas. If operating conditions are maintained
according to specifications, the NOX concentration in the tail
gas is below 50 ppm.
Economic Factors - The capital and operating costs of the molecular
.sieve method for NOX abatement are given in Table IV-4. The process
is capital intensive, and the annual costs associated with replac-
ing the molecular sieve materials and electric power costs are also
significant. Unlike the catalytic reduction process, nitric acid
is recovered and can be credited to the operating costs.
Energy Requirements - The energy requirements for the molecular
sieve method for NOX abatement are given in Table IV-5. Power
requirements are high because of the added compression requirements
and the need to regenerate the sieve.
Technical Considerations - The absorption techniques involve swing
operation. This may be a problem, because the burner in the nitric
acid plant requires good, steady-state operation to minimize
platinum losses and to prevent explosions from improper ammonia-
air mixtures.
It is necessary to replace molecular sieves after a certain number
of operating hours. Maintenance of proper operating conditions is
important to avoid degradation of the sieves. In some cases, the
cost of sieve replacement may be significant. Also, the molecular
sieve method uses relatively high energy compared to the other NOX
abatement methods (except the catalytic method).
36
-------
(3) Extended Water Absorption or Grande Paroisse Process
In the Extended Water Absorption or Grande Paroisse Process, tail gas
from the existing absorber tower, which typically contains between 1,500 and
5,000 ppm NOX, is routed to the secondary absorber for additional "extended
absorption" of nitrogen oxides. The tail gas is contacted counter-
currently with process water, and additional acid produced in the secondary
absorber is pumped to the existing absorber. A startup acid pump is included
to circulate a large quantity of weak acid through the secondary absorber to
fill the absorber trays as quickly as possible during startup.
Figure IV-5 is a simplified flow sheet for the process as installed in a
typical nitric acid plant. The exit solution is used to feed the existing
absorber, eliminating any liquid stream from the NOX abatement process. The
process has no effect on the quality of the nitric acid produced.
« Current Status of the Grande Paroisse Process - The Grande Paroisse
process is well-developed in Europe, and has been used in the design
and construction of over 30 plants throughout the world to date.
In the United States, the Grande Paroisse NOX abatement process has
been applied to five plants having production capacities of 125,
240, 300, 315, and 360 tpd. One additional plant having a capacity
of 1,000 tpd using the Grande Paroisse process is under construction.
EXISTING
SECONDARY ABSORBER
TQWER
.
NITROUS GAS
| I
NITRIC ACID I T |
±r_L
RECOVERED
NITRIC ACID
TO EXISTING
TAIL GAS PREHEATER
=^>
/'
START-UP
' ONLY
PROCESS
WATER
ACID TRANSFER
PUMPS
(ONE IS SPARE)
START-UP
PUMP
PROCESS WATER
PUMP
(EXISTING)
Source: J. F. Pritchard Co. Catalog
Figure IV-5. Grande Paroisse NOX Abatement Process
37
-------
Effluent Control - The only flow streams from the absorber are tail
gas and weak nitric acid solution. The tail gas meets the EPA
NOX standards. The weak acid is used as a feed makeup water to the
nitric acid absorber.
Economic Factor - The capital cost and the operating cost of the
Grande Paroisse NOX abatement process are given in Table IV-4. The
process is capital intensive. Costs which are not investment-
related are minor and are more than offset by the credit for
nitric acid recovered.
Energy Requirements - The energy requirements for the Grande
Paroisse process for NOX abatement are given in Table IV-5. It
uses less energy than any of the other processes, with the possible
exception of the Masar process.
Technical Consideration - The Grande Paroisse process has been
accepted where the cost of feedstock and utilities is noticeably
higher (Europe). The process may be used in a new plant or may be
retrofitted in an existing plant. The process is based on the
conversion of NO to useful NC^, rather than to nonproductive
nitrogen. The rate of reaction varies directly with the square of
the pressure. Therefore, the operating pressure determines the
success of the NOX abatement in the tail gas. The preferred
absorber pressure for an existing plant is above 100 psia and for
a new plant it is above 150 psia. The capital cost increases
significantly if the operating pressures are reduced (to maintain
the same NOY concentration in the tail gas).
A
(4) CDL/Vitok Process*
The process uses the principle of scrubbing tail gas with nitric acid
under conditions which reduce the nitrogen oxides to the desired level. Both
physical absorption and stripping and chemical oxidation absorption are used.
The reaction may be catalyzed in some applications to reduce the size of the
equipment required. No chemicals other than water and nitric acid are required
for the process, thus avoiding additional new waste disposal problems and
cost. The nitric acid is not consumed, being an internal recycle, and the
water is only that required for the manufacture of the acid, and this becomes
a part of the product. All the nitrogen oxides removed from the tail gas are
converted to nitric acid at concentration levels that can be commercially
utilized.
Current Status of the CDL/Vitok Process - The CDL/Vitok process
has been applied to one commercial plant having a capacity of 350
tpd. The NOX content in the tail gas is less than 3 Ib/ton of
nitric acid. Also the process was tested for one year in a demon-
stration size plant in an ammunition plant.
*Maryland, B.J., "The CDL/Vitok Nitrogen Oxides Abatement Process," presented
at the Environmental Symposium of the Fertilizer Institute, January, 1976,
New Orleans.
38
-------
It is expected that the CDL/Vitok process will be applied to four
plants next year. These plants have a rated capacity of 60, 60,
150, and 250 tpd.
Effluent Control - The only effluent stream from the CDL/Vitok
process is tail gas. The tail gas will meet the NOX stationary
source standard.
Economic Factor - The capital cost and the operating cost of the
CDL/Vitok process for NOX abatement are given in Table IV-4.
The CDL/Vitok process has the lowest capital and operating costs.
Energy Requirements - The energy requirements for the CDL/Vitok
processes are given in Table IV-5. It uses approximately 25% of
the energy of the catalytic reduction process.
Technical Considerations - The CDL/Vitok process is similar to the
Grande Paroisse process. The two processes differ in operating
conditions: the CDL/Vitok process uses a higher liquid-to-gas
ratio and a lower operating temperature. It is claimed that only
one absorber is required for the CDL/Vitok process. However, the
increased liquid flow rate may affect the tower capacity.
(5) Masar Process
The Masar process (see Figure IV-6), as applied to nitric acid plants,
takes the tail gas from the exit of the absorption tower and passes it to a
gas chiller where it is cooled. During the cooling operation, condensation
occurs, with the formation of nitric acid. The chilled gas and condensate
passes into section A of the Masar absorber.
The Masar absorber is divided into three sections, A, B, and C.
Masar Absorber Section A - In this section, the chilled gas and
condensate represent feed gas stream, and chilled feed water
(from Section C) represents liquid stream. The feed water stream,
mixed with weak nitric acid, flows down in Section A countercurrent
to the tail gas to scrub NOX from the tail gas.
The liquid stream is circulated through a chiller, E, to remove
reaction heat. The bleed stream from the Section A is weak nitric
acid and is fed to the nitric acid absorber in the main plant to
serve as its feed water.
Masar Absorber Section B - The tail gas passes into Section B of the
Masar absorber, where it is scrubbed with a circulating urea-
containing solution. A urea/water solution (concentrated Masar
solution) is made up in a storage tank and metered into the
recirculating system at a rate necessary to maintain a specified
minimum urea residual content. As the solution scrubs the tail
gases, both nitric and nitrous acids are formed, and the urea in
39
-------
CONC. MASAR
SOLUTION
SPENT MASAR
SOLUTION
(SLOWDOWN)
LIQUID
CHILLER
TAIL GAS
CHILLER
LIQUID
CHILLER
Source: MASAR, Inc., Catalog
FEED WATER
FEED WATER
TO NITRIC ACID PLANT
ABSOR. COL.
SECTION
SECTION
B
SECTION
A
PUMP
TAIL GAS
TO
NITRIC ACID
PLANT
MASAR
ABSORBER
Figure IV-6. Masar Process for NOX Abatement
-------
gases, both nitric and nitrous acids are formed, and the urea in
the solution reacts with the nitrous acid. As the solution is
circulated, the nitric acid content rises and some of the urea
present hydrolyzes and forms some ammonium nitrate. To maintain
the system in balance, some of the circulated solution (spent Masar
solution) is withdrawn. Disposition of this solution is discussed
below. The recirculated solution is also pumped through a chiller,
F, to remove the heat of reactions and to maintain the desired
process temperature in Section B.
Masar Absorber Section C - The tail gases from Section B pass into
Section C, where they are scrubbed by the feed water stream. The
feed water is chilled in Section C by countercurrent flow of chilled
gas. The chilled water from the bottom of Section C is used as feed
water in Section A.
The tail gases then leave the Masar absorber and pass on to the
existing mist eliminator and heat exchanger train of the nitric acid
plant. In the application of this process at Illinois Nitrogen,
the cooling medium used in the gas chiller is liquid ammonia. The
vaporized ammonia is subsequently used as the feed to the plant
ammonium nitrate neutralizer. For non-ammonium nitrate producers,
mechanical refrigeration could be used or the ammonia vapor could be
used in the nitric acid converter directly.
Current Status of the Masar Process - The Masar process is now
being used in three U.S. nitric acid plants: two 350 tpd
capacity, and one 250 tpd capacity.
Effluent Control - The effluent streams from the Masar process are
tail gas and spent Masar solution.
The tail gas has met regulatory standards with regard to NOX abate-
ment. The NOX in the tail gas exhaust from one operating plant
has been between 100 and 200 ppm for a one-year operation period.
Some data show NOX in tail gas as low as 57 ppm.
The spent Masar solution contains urea and ammonium nitrate. This
is spent in the form of a weak solution. Approximately 25% of the urea
in the feed is present in the spent solution. The ammonium nitrate
concentration is two to three times the concentration of urea in
the spent solution. The solution can be utilized in preparing
fertilizer solution. Companies that do not make fertilizer solutions
may sell the solution to companies that do or to farmers for direct
application.
Economic Factors - The capital cost and the operating cost of the
Masar process for NOX abatement are given in Table IV-4.
.The credit for the spent Masar solution is determined by using $160/
ton for urea and $100/ton for ammonium nitrate.
41
-------
If the spent Masar solution is used in the fertilizer industry,
there will be some cost associated with handling the solution.
Alternatively, the solution may be sold to farmers. In the latter
case, the price may be lower.
Energy Requirements - The energy requirements for the Masar process
are given in Table IV-5. It uses only about 10% as much energy as
does the catalytic reduction process.
Technical Considerations - Essentially 80% of the NOX recovered is
available in direct usable form (weak nitric solution), as discussed
previously. The remainder is abated with the use of urea. This
leads to the discharge of spent Masar solution, containing urea
and ammonium nitrate. Application of the spent Masar solution
should be determined.
The process requires refrigeration. Selection of the cooling medium
is important. Alternatively, mechanical refrigeration may be used.
(6) Alkali Scrubbing Process
Alkaline scrubbers also reduce the emission of nitrogen oxides
effectively. Data for five plants are presented in Table IV-7. The two-
stage, sodium hydroxide-water scrubber performed exceptionally well, with an
overall reduction of 91% in nitrogen oxides content. The data on the sodium
carbonate scrubber show a very high (2.5%) nitrogen oxides concentration in
gases entering the sodium carbonate scrubber; this high value might indicate
that the principal purpose of the scrubber was to produce nitrite and nitrate
salts rather than to reduce emissions below the usual 0.15 - 0.40% nitrogen
oxides concentration characteristic of untreated tail gas. Alkaline scrubbing
is used only if the production of nitrates is desired.
TABLE IV-7
EMISSIONS DATA FOR NITRIC ACID PLANTS
HAVING ALKALINE SCRUBBING EQUIPMENT
Scrubber
Type of Control NaOH + H20 Na2C03
No. of Stages 2 1
Percent Reduction in
Nitrogen Oxides 91 94
Pounds of Nitrogen Oxides Emitted
per ton of Acid Produced 4 27-54
(100% Basis)
Source: Atmospheric Emissions from Nitric Acid Manufacturing
Processes, USHEW, PHS-999-AP-27, 1966.
42
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2. Conversion to Fuel Oil in Mixed Fertilizer Plants Equipped With
Bag Filters
a. Wet Scrubber Currently Installed for Control of Particulate Emissions
Currently, approximately 80% of the estimated 200 ammoniation granula-
tion fertilizer plants use wet scrubbers to control particulate emission
levels. These plants are expected to have relatively few problems in
switching from natural gas to fuel oil for drying. The capital cost for
new burners, oil tanks, piping, and miscellaneous equipment is about
$10,000 for a typical dryer. Most plants have already installed stand-by
fuel oil equipment, so the investment has already been incurred. There
are no significant differences in operating costs, aside from the fuel
cost differential itself.
b. Base Line Technology Used for Comparison (Bag Filters Currently Installed)
For purposes of analysis, the base line plant is a 47,000 metric-ton-
per-year ammoniation granulation plant using a natural gas-fired dryer and
equipped with a bag house filter to control particulate emissions.
Of the three types of ammoniators illustrated in Figure IV-7, the
rotary-drum design is most common. Figure IV-8 presents a simplified flow
diagram for an ammoniation granulation plant, while Figures IV-9 and IV-10
show additional details of the material handling and dust collection sys-
tems, respectively. The base case plant has no water effluent and consumes
from 200,000 to 400,000 Btu per ton of product for drying.
Table IV-8 presents additional production statistics for the base line
plant. Uncontrolled and controlled emission factors (and the total amounts
of controlled emissions) are presented in Tables IV-9 and IV-10, respectively.
The allowable emission rate per ton of product for new plants is 2.1 pounds.
The uncontrolled emission rate in Table IV-9 is 4.6 pounds per ton, indi-
cating a 60% efficiency requirement. For existing plants, the average of
state emission regulations for plants of less than 30 tons per hour is
3.59 pO'62^ where P is the production rate in tons per hour. For plants of
30 tons per hour or greater, the formula is 17.31 P°-16. In cases where
gaseous effluents exceed existing EPA standards, installation of an
auxiliary-scrubber is required. The composition and quantity of stack gas
will vary considerably depending on product formulation and production
control.
c. Installation of Scrubber on Bag House-Equipped Plants When Converting
From Natural Gas to Fuel Oil
As discussed earlier, some fertilizer dryers fired by natural gas
employ bag houses for air pollution control. In the base case, when fuel
oil has been substituted for natural gas, operational problems have some-
times resulted from the plugging of the bag house filter media with products
43
-------
LIQUIDS
SOLIDS
PRODUCT
SOLIDS
LIQUIDS-
SURGE
HOPPER
RECYCLE
FEEDER | PUG MILL j
DRIER
COOLER
OVERSIZE MILL
PRODUCT
SOLIDS
| CONTINUOUS FEEDERS
RECYCLE
LIQUIDS
»-
^
DRUM
AMMONIATOR
GRANULATOR
DRIER
OVERSIZE MILL
COOLER
PRODUCT
Source: Sauchelli, V., Manual on Fertilizer Manufacture, Industry Publications, Inc.,
Caldwell, New Jersey, 1963.
Figure IV-7. Batch-Mixer, Pug-Mill and Rotary-Drum Ammoniation
44
-------
SOLID
MATERIALS
EMISSIONS
SOLIDS
MIXING
EMISSIONS
CRUSHING
MILL
EMISSIONS
AMMONIATOR
-GRANULATOR
LIQUID
RAW MATERIAL
EMISSIONS
DRYER
EMISSIONS
COOLER
FINES AND RECYCLE
Source: Monsanto Research Corporation
EMISSIONS
f
EMISSIONS
t
DOUBLE DECK
SCREEN
PRODUCT
Figure IV-8. Simplified Flow Diagram of an Ammoniation Granulation Plant
-------
CL
JSTER
HOPPEF
S
PHOSPHORIC ACID AND/OR
SUPERPHOSPHORIC ACID
PRODUCT
Source: Tennessee Valley Authority
Figure IV-9. Detailed Schematic Diagram of Rotary-Drum Ammoniation Plant
-------
SCREEN
Source: Tonnoifoo Valley Authority
Figure IV-10. Detail of Granulation Plant Dust Collection System
-------
TABLE IV-8
AMMONIATION GRANULATION PRODUCTION STATISTICS - 1973
Number of Plants
Total Annual Production,
million tonnes (tons)
Annual Plant Production Rate,
tonnes/year (tons/year)
Average Annual Production Rate,
tonnes/year (tons/year)
Plant Design Hourly Production Rate,
tonnes/hour (tons/hour)
Average Annual Operating Period,
hours/year
Actual Average Production Rate,
tonnes/hour (tons/hour)
195
9.14
(10.08)
9,000- 90,000
(10,000-100,000)
46,870
(51,690)
4.5-90
(5-100)
3,894
12.04
(13.27)
Source: Monsanto Research Corporation
48
-------
TABLE IV-9
UNCONTROLLED EMISSION FACTORS FOR AMMONIATION GRANULATION PLANTS
vo
Emission
kg/tonne (pound/ton)
Emission Source
Cateogry
Material storage
and handling
Ammoniator granulator 0.503 + 104%
"(1.006 + 104%)
Ammonia
0
Total Total Total
Chlorine Fluorine Phosphorus Particulate
0 0 0 0.5
(1.0
+ 300%a
+ 300%)
Dryer and cooler
Screen and oversize
mill
Bagging and loading
Total plant
0.316 + 44%
(0.633 + 44%)
0
0.819 + 66%
(1.639 + 66%)
0.030 + 186% 0.0013 + 57%
(0.060 + 186%) (0.0025 + 57%)
0.014 + 175% 0.0083 + 70%
(0.028 + 175%) (0.0167 + 70%)
0
0.0011 + 87%
(0.0022 + 87%)
0.175 + 356%b
(0.350 + 356%)
0.0316 + 133% 0.23 + 48%
(0.0633 + 133%) (0.46 + 48%)
0
0.25 + 300%)a
(0.5 + 300%)
0.25
(0.5
+ 300%a
+ 300%)
0.044 + 175% 0.0096 + 61% 0.0327 + 133% 1.40 + 300%
(0.088 + 175%) (0.0192 + 61%) (0.0655 + 133%) (2.91 + 300%)
*These values are a result of engineering estimates of similar processes because no source test data is
available and the values may vary by a factor of three.
3The large error is due to only two data points which statistically results in a large spread for 95%
confidence range. The standard deviation in the two data points is +40%.
Source: Monsanto Research Corporation
-------
TABLE IV-10
EMISSION FACTOR AND TOTAL MASS OF CONTROLLED
EMISSIONS FROM FERTILIZER MIXING PLANTS
O
Ammoniation Granulation Plants
Emission Factor, Total Mass,
Emission Species kg/tonne tonnes/year
Ammonia 0.123 + 66% 1,120 + 740
Total chlorine 0.0066 + 175% 59 + 103
Total fluorine 0.0014 + 61% 13+8
Total phosphorus 0.0049 + 133% 45 + 60
Particulate 0.21 + 300%C 1,920+5,760
aBased on a minimum control efficiency of 85%. All plants have
control equipment which is 85% to 99.5% efficient.
Source: Monsanto Research Corporation
of incomplete combustion. However, there is a strong indication that such
problems can usually be overcome by modifying the combustion process. If
this measure is generally successful, it will still be possible to use bag
houses when fuel oil is used. However, should the use of bag houses prove
to be incompatible with the use of fuel oil, wet scrubbers will have to
be employed. The capital and operating costs for a wet scrubber capable
of handling a gas stream of 13,000 cfm and at 38,000 hours of annual opera-
tion are shown in Table IV-11.
In the operation of a wet scrubber, the scrubber water is typically
recycled after each pass through the scrubber. Since a portion of the
water is evaporated on each pass, makeup water must be added. To prevent
the buildup of absorbed materials in the scrubber water, a small portion
of the scrubber water flow must be purged from the system. This purge
stream is a contaminated wastewater stream and a potential source of water
pollution. An estimation of the characteristics of this wastewater stream
is shown below:
50
-------
TABLE IV-11
MIXED FERTILIZER PLANT SCRUBBER COSTS
(Production Basis: 52,000 tons/yr)
CAPITAL INVESTMENT $70,000
INDIRECT COSTS
Depreciation ((? 9.U/yr) 6,360
Return on Investment (0 20%/yr) 14,000
Taxes and Insurance (@ 2%/yr) 1,400
TOTAL INDIRECT COSTS $21,760
DIRECT OPERATING COST
Operating Labor 3,500
Maintenance Labor and Materials 3,500
Electricity 5,700
TOTAL DIRECT OPERATING COST $12,700
TOTAL ANNUAL COST $34,460
UNIT COST ($/ton of fertilizer) $0.66
Source: Arthur D. Little, Inc. estimates.
Wastewater Flow Rate = 7,660 gallons/day
(during actual drying time)
Estimated Wastewater Composition
(based on 90% scrubber efficiency)
Constituent Concentration (mg/liter)
Ammonia 275
Chloride 150
' Fluoride 75
Phosphorus \ 275
Suspended Solids 100
Ammonia, fluoride, and phosphorus are the principal pollutants of concern
in the wastewater stream. Their concentration levels must be reduced prior
to discharge into a receiving stream.
To remove the pollutants, lime treatment (with aeration) can be employed.
The addition of lime will raise the pH of the wastewater, thus converting
ammonium ions into ammmonia gas, which can then be stripped from the waste-
water by aeration. Lime will also cause the fluoride ions and phosphorus
(as phosphate ions) to precipitate out of solution as calcium fluoride and
calcium phosphate. The reactions and aeration can be performed in conventional
51
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mixing basins and the settling of precipitates can be performed in a con-
ventional clarifier. The final effluent from the lime treatment must be
neutralized with sulfuric acid prior to discharge. The estimated composi-
tion of the treated effluent is approximately:
Ammonia 30 mg/liter
Chlorine 150 mg/liter (no removal)
Fluoride 15 mg/liter
Phosphorus 20 mg/liter
Suspended Solids 20 mg/liter
An estimate of the costs of treating the scrubber water is presented in
Table IV-12.
TABLE IV-12
MIXED FERTILIZERS - FUEL OIL ALTERNATIVE
SCRUBBER WATER TREATMENT COSTS
(Production Basis: 52,000 tons/yr)
CAPITAL INVESTMENT $50,000
INDIRECT COSTS
Depreciation (@ 9.1%/yr) 4,600
Return on Investment (@ 20%/ys) 10,000
Taxes and Insurance (@ 2%/yr) 1,000
TOTAL INDIRECT COST $15,600
DIRECT OPERATING COST
Operating Labor ($6.10/hr + 100% of labor for 7,300
overhead)
Maintenance Labor and Materials 2,000
Chemicals (lime and acid) 1,500
Electricity (@ $0.02/fcoh) 600
Sludge Disposal (@ $5.00/metric ton) 500
TOTAL DIRECT OPERATING COST $11,900
TOTAL ANNUAL COST 27,500
UNIT COST ($/ton of fertilizer) $0.53
Source: Arthur D. Little, Inc. estimates.
52
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The treatment system will result in the following consumption of chemicals
and energy:
Hydrated Lime 5.4 tons/year
Sulfuric Acid-100% Basis 10 tons/year
Electrical Energy 30,000 kWh/yr (0.64 kWh/metric ton
of fertilizer)
In addition, an estimated 100 tons per year of sludge having a solid con-
centration of 10% will be generated. This sludge may contain as much as 0.5%
fluorides and 2.0% phosphates in addition to soluble ammonia; ermsequently its
disposal into landfills must be done with care to insure that leaching into
ground or surface waters does not occur.
d. Continued Control of Particulate Emissions With Bag Houses When Converting
From Natural Gas to Fuel Oil
For those ammoniation granulation plants that now have bag filters it
appears that the problem of filter bag clogging may be corrected through
proper attention to equipment design and operation.
Many ammoniation granulation plants have already installed dual-purpose
burners and fuel oil storage systems to cope with the interruptable natural
gas service which they have been forced to accept. A few producers have
chosen to use propane when natural gas is shut off, rather than invest in fuel
oil equipment. For those plants with fuel oil equipment, no incremental invest-
ment is required for conversion to fuel oil. However, operating costs increase
slightly, because cleaning of the bag filters must be done six time per year
(with ideal burner performance) rather than four times per year as with natural
gas.
Most of the problems occur during startup, before equilibrium operating
temperatures are reached. This can be alleviated by preheating the fuel oil,
by using proper, well-adjusted burners, and by preheating the dryer before
charging the material to be dried. In some cases, particularly where the
dryer exit gases may cool before entering the bag house, an auxiliary burner
may be required (Figure IV-10).
The estimated operating costs for a bag house on the base line ammonia-
tion granulation plant are shown in Table IV-13. The incremental costs for
installing fuel oil storage equipment and dual burners are presented in
Table IV-14. If fuel oil equipment is already installed, the incremental
costs are much lower, as indicated in Table IV-15. As may be seen by com-
paring these costs with the incremental costs required for installation of
a scrubber system, ungrading the equipment and operating procedures for use
of fuel oil with the bag house is considerably less expensive. In cases where
difficulty is experienced because of incomplete combustion of the fuel oil,
industry observers suggest that an afterburner or other special burner design,
such as an infrared burner now under development (Burdett Company, private
communication) could solve this problem. The cost of such burners for the
base case fertilizer drying plant would be about $15,000.
53
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TABLE IV-13
MIXED FERTILIZER PLANT BAG HOUSE COSTS
(Production Basis: 52,000 tons/yr)
CAPITAL INVESTMENT $80,000
INDIRECT COSTS
Depreciation (8 9.1%/yr) 7,280
Return on Investment (0 20Z/yr) 16,000
Taxes and Insurance (@ 22/vr) '
TOTAL INDIRECT COST 24,880
DIRECT OPERATING COST
Operating Labor ($6.10/hr + 100% OHD) 4,000-
Maintenance Labor and Materials 4,000
Electricity (@ $0.02/kWh) 1,800
TOTAL DIRECT OPERATING COST 9,800
TOTAL ANNUAL COST 34,680
UNIT COST ($/ton of fertilizer) $0.67
Source: Arthur D. Little, Inc. estimates.
TABLE IV-14
FERTILIZER DRYING, COSTS FOR MAIN AND AUXILIARY BURNERS
(Production Basis: 52,000 tons/yr)
CAPITAL EQUIPMENT
Main Burner <4 x 106 Btu/hr), Storage and $9,500
Related Equipment
Auxiliary Burner (0.2 x 106 Btu/hr) and 500
Related Equipment
TOTAL $10,000
INDIRECT COSTS
Depreciation (@ 9.1Z/yr) 910
Return on Investment (9 20Z/yr) 2,000
Taxes and Insurance (? 2%/yr) 200
TOTAL INDIRECT COST $3,110
DIRECT OPERATING COST
Operating Labor 500
Maintenance Labor and Material 500
TOTAL DIRECT OPERATING COST 1,000
TOTAL ANNUAL COST $14,110
UNIT COST ($/ton) $0.27
Source: Arthur D. Little, Inc. estimates.
54
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TABLE IV-15
FERTILIZER DRYING, INCREMENTAL COST OF BURNING FUEL OIL WITH BAG FILTERS
(Production Basis: 52,000 tons/yr)
CAPITAL INVESTMENT
Auxiliary Burner, Piping and Misc. $500
INDIRECT COSTS
Depreciation (@ 9.1%/yr) 45
Return on Investment (@ 20%/yr) 100
Taxes and Insurance (@ 2%/yr) 10
TOTAL INDIRECT COSTS 155
DIRECT OPERATING COST
Operating Labor 2,000
Maintenance Labor and Materials 2,000
TOTAL DIRECT OPERATING COST $4,000
TOTAL ANNUAL COST $4,155
UNIT COST ($/ton of fertilizer) $0.08
Source: Arthur D. Little, Inc. estimates.
55
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V. IMPLICATIONS OF POTENTIAL CHANGES
A. AIR POLLUTION CONTROL IN NITRIC ACID PLANTS
The manufacture of nitric acid produces significant emissions of nitrogen
oxides to the atmosphere. The most widely used process for pollution control
is the catalytic decomposition of the nitrogen oxides to nitrogen and oxygen.
This process is energy intensive and is particularly expensive for those few
nitric acid plants which cannot recover the energy in the form of usable steam.
The problem is aggravated because natural gas is the required energy source.
Most plants are limited in the quantities of gas they can purchase, and such
natural gas is critical and non-substitutable for the manufacture of ammonia,
which in most places occurs at the same site. Natural gas use for pollution
control reduces the amount available for other purposes, thus effectively
reducing production. The natural gas requirement for pollution control of a
300 tpd nitric acid plant is 232.6 x 10^ Btu per year. This amount could be
used to produce 6,600 tons of ammonia.
The process produces steam, which can be used elsewhere in the plant
complex, and it may be argued that this reduces the energy input at some other
point. Such argument may not be valid for two reasons:
1. Not all plants have use for the steam; and
2. Such steam, if needed, could otherwise be provided with a fuel other
than natural gas.
The other abatement systems becoming available hold the promise of
satisfactory control of emissions and at lower investment costs, lower oper-
ating costs, significantly lower energy requirements, and no need for natural
gas as the energy source. Also, because the catalytic reduction process is
usually too expensive to operate in plants using low-pressure processes to
nitric acid, two or three of the alternate processes allow more economical
recovery for such plants. The other processes suffer from problems of main-
tenance of stringent operating conditions (Molecular Sieve), inapplicability
to low-pressure nitric acid processes (Grand Paroisse), and too little actual
operating experience (CDL/Vitok and Masar).
The economics of the pollution control options are provided in Table V-l.
Investment in a 300 tpd nitric acid plant with no pollution control is about
$5.5 million, and the cost of manufacture, including profit, is $56.48 per ton,
although this cost is strongly affected by the price of ammonia, which we have
56
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TABLE V-l
CAPITAL COST AND OPERATING COST
FOR
NO ABATEMENT SYSTEMS FOR A 300 TPD NITRIC ACID PLANT
Capital Cost
Operating Labor
Maintenance
Catalyst or Sieve
Cooling Water
Steam (credit)
Electricity
Boiler Feedwater
Fuel
Depreciation
Return on Investment
Taxes and Insurance
Nitric Acid (credit)
Urea
Ammonium Nitrate
Net Operating Cost, ($/yr) 628,270
($/ton) 6.16
Catalyst
Reduction
1,384,000
4,400
4,400
77,800
(387,590)
20,890
12,850
465,120
125,900
276,800
27,700
Molecular
Sieve
1,200,000
4,400
4,400
45,600
1,980
6,120
52,550
Grande
Paroisse
Process
1,000,000
4,400
4,400
1,840
14,690
CDL/
Vitok
575,000
4,400
4,400
14,980
17,500
43,250
Masar
663,000
4,400
7,550
32,070
3,260
32,640
109,090
240,000
24,000
(112,200)
408,580
4.01
90,910 52,300 60,300
200,000 115,000 132,600
20,000 11,500 13,260
(102,000) (102,000) (89,760)
74,528
(42,500)
234,200 161,330 195,708
2.30 1.58 1.92
valued at $100 per ton. The catalytic reduction process thus adds 25% to the
investment and 11% to the cost of manufacture. The molecular sieve and
Grande Paroisse processes have almost as much investment, but add only 7%
and 4%, respectively, to the operating costs. The newer CDL/Vitok and Masar
processes appear to offer significant savings in both investment and
operating costs.
Energy requirements are also much lower in each of the four alternatives
to the catalytic reduction process (see Table V-2). Of particular interest
is that only the catalytic reduction process requires natural gas.
B. FERTILIZER DRYING (
1. Continued Use of Bag House With Improved Design and Operation
For the ammoniation granulation plants considered, which are already
equipped with bag houses, the impact on pollution control and energy require-
ments for upgrading design and operation is negligible. Performance of the
bag filter will be improved through proper attention to operation and design.
The key factors in successful use of fuel oil are a properly designed and
adjusted burner and combustion chamber and pre-heating of all exhaust gas
before it enters the bag filter. Pre-heating the fuel oil before it enters
the combustion chamber may also help to achieve full combustion; however,
this investment (several hundred dollars) should not be necessary for No. 1
or No. 2 fuel.
57
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TABLE V-2
ENERGY REQUIREMENT IN NOX ABATEMENT SYSTEMS
FOR A 300 TPD NITRIC ACID PLANT
(109 Btu/yr)
Catalytic
Reduction
Molecular
Sieve
Grande
Paroisse
CDL/
Vitok
Masar
Steam (Credit)
Electrical
Natural Gas
Oil
(129.20)
10.97
232.56
114.83
2.04
27.59
16.32
45.95
7.71
7.71
5.83
22.71
28.54
10.69
1.71
12.40
In terms of economic impact, the added cost of upgrading equipment to
handle fuel oil is relatively small when compared to the original bag house
investment. The incremental cost of approximately $0.08 per ton of
product represents about 0.05% of current product price (approximately$160 per
ton, January 1976). As such, this added cost is viewed as having a negligible
impact on the industry. The cost premium for fuel oil over natural gas (per
Btu) has not been considered here, because the switch to fuel oil is a result
of factors beyond the operation control. This could be a significant cost.
2. Conversion From Bag House to Wet Scrubber With Fuel Change From Natural
Gas to Fuel Oil
It is unlikely, in view of the costs involved, that an ammoniation
granulation plant operator would choose to install a wet scrubber when he
has already invested in a bag house for pollution control. Assuming that
there is no scrubbing equipment now in place, the incremental investment for
installation of a scrubber and the necessary effluent treatment equipment, at
$1.19 per ton, would be more than ten times as expensive as the upgraded
bag house system described above. In addition, the energy requirements for
a wet scrubber of comparable efficiency would be considerably higher than for
the bag house system. The fuel requirements for fertilizer drying would be
nearly identical (slightly less for the scrubber), but the power requirements
for scrubber operation are approximately three times as great as for operation
of the bag house.
In summary, the amount of fuel required for drying would be about the
same for either option, while the operating power would be much greater for
the scrubber. In terms of both the required incremental investment and the
performance per unit of operating power, the upgrading of current bag house
equipment is the preferred alternative for a typical plant equipped with bag
filters (see Table V-3).
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TABLE V-3
COMPARISON OF SCRUBBER AND BAG HOUSE COSTS AND ENERGY CONSUMPTION FOR
TREATING MIXED FERTILIZER PLANT GASEOUS AND PARTICULATE WASTES
(Production Basis-50,000 short tons/yr)
Scrubber Alternative
Scrubber
Scrubber Effluent Treatment
Total
Less Variable Cost of In-Place
Bag House
Incremental
Annual Cost
($/ton)
$0.66
0.53
1.19
.19
Incremental
Annual Energy
Consumption
(million Btu)
$2,990
315
Total Incremental Cost and Energy 1.00
3,305
960
$2,345
Bag House Upgrade Alternative
Burner Conversion and Auxiliary Equip $0.08
760J
Apparent Advantage of Bag House Upgrade
12X
3X
1 Assumes 0.2 x 10 Btu/hr for 3800 hours of operation annually.
59
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/7-76-0340
2.
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
ENVIRONMENTAL CONSIDERATIONS OF SELECTED ENERGY CON-
SERVING MANUFACTURING PROCESS OPTIONS. Vol. XV.
Fertilizer Industry Report
5. REPORT DATE
December 1976 issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Arthur D. Little, Inc.
Acorn Park
Cambridge, Massachusetts 02140
10. PROGRAM ELEMENT NO.
EHE624B
11. CONTRACT/GRANT NO.
68-03-2198
12. SPONSORING AGENCY NAME AND ADDRESS
Industrial Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
FINAL
14. SPONSORING AGENCY CODE
EPA-ORD
15.SUPPLEMENTARY NOTES Vol. Hi-xiv, EPA-600/7-76~034c through EPA-600/7-76-034n, refer
to studies of other industries as noted below; Vol. I, EPA-600/7-76-034a is the
Industry Summary Report and Vol. II, EPA-600/7-76-034b is the Industry Priority Report
16. ABSTRACT
This study assesses the likelihood of new process technology and new practices being
introduced by energy intensive industries and explores the environmental impacts of
such changes.
Specifically, Vol. XV deals with the fertilizer industry and examines two areas in
which energy conservation and pollution control are in conflict: the reduction of
nitrogen oxide emissions from nitric acid plants and switching from natural gas to
fuel oil for firing fertilizer dryers where emissions are presently controlled by
bag filters. Vol. III-XIV deal with the following industries: iron and steel,
petroleum refining, r-lp an^ paper, olefins, ammonia, aluminum, textiles, cement,
glass, chlor-alkali, phosphorus and phosphoric acid, and copper. Vol. I presents
the overall summation and identification of research needs and areas of highest
overall priority. Vol. II, prepared early in the study, presents and describes the
overview of the industries considered and presents the methodology used to select
industries.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Energy
Pollution
Industrial Wastes
Fertilizer
Ammonia, Phosphorus
Nitric Acid
Particulate Control
Manufacturer Processes
Energy Conservation
Granulated Fertilizers
Air Emission Control
Nitrogen Oxide Control
13B
3. DISTRIBUTION STATEMENT
Release to public
19. SECURITY CLASS (ThisReport)
unclassified
21. NO. OF PAGES
74
20. SECURITY CLASS (Thispage)
unclassified
22. PRICE
EPA Form 2220-1 (9-73)
60
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