Improved Nitric Acid Production via Cobalt Oxide...

Mentor: Bill Keesom, Jacobs Engineering

Improved Nitric Acid Production via Cobalt Oxide Catalysis for use in Ammonia-based Fertilizers

Team Foxtrot

Thomas Calabrese

Cory Listner

Hakan Somuncu

David Sonna

Kelly Zenger

4/24/2012

University of Illinois at Chicago – Department of Chemical Engineering

Improved Nitric Acid Production via Cobalt Oxide University of Illinois at ChicagoCatalysis for use in Ammonia-Based Fertilizers

TABLE OF CONTENTS

I. Executive Summary 3II. Introduction 4III. Description of Process 6IV. Process Control 12V. Environmental Concerns 13VI. Economics 17VII. Competing Processes 19VIII.

Recommendations 22

IX. Appendices 23 Design Basis 24 Block Flow Diagram 25 Process Flow Diagram 27 Material Balance 28 Energy Balance 35 Physical Properties of Process Components 47 Annotated Equipment List 51 Economic Evaluation 58 Utilities 66 Conceptual Control Scheme 68 General Arrangement – Major Equipment Layout 71 Distribution and End-Use Issues Review 73 Constraints Review 74 Applicable Standards and Safety Review 79 Project Communications 86 Special Thanks 86 Information Sources and References 87

Senior Design II – CHE 397 Team Foxtrot Spring 2012Calabrese, Listner, Somuncu, Sonna, Zenger Page: 2


EXECUTIVE SUMMARY

In order to produce the ammonia-based fertilizer, several intermediate processes are

required; nitric acid formation is one such process. The raw materials used to produce nitric acid

include 572 TPD of ammonia, provided to the plant from the upstream ammonia team, and air

that will be taken from the atmosphere. The plant will produce 3,289 TPD of a 63% weight nitric

acid solution. 2,571.2 TPD will be provided to the downstream ammonium nitrate team while the

rest is sold to the open market. 1,843 TPD of high quality steam (1,250 psi and 970°F) is

generated in the process and will be provided to the combined heat and power team in exchange

for electricity.

Ammonia is converted in a catalytic reactor to nitrogen monoxide and is further oxidized

to nitrogen dioxide as the hot gases cool before being absorbed to produce the nitric acid

product. With the continuing rise in precious metal costs, platinum-rhodium catalysts are

becoming less economically viable as a catalyst for ammonia oxidation. The platinum-rhodium

catalyst requires frequent replacement and loss is prevalent at the high reaction temperature. A

relatively new catalyst that has been developed, making use of cobalt oxide, provides the same

conversion benefits of platinum-rhodium, while being vastly cheaper and inhibits the formation

of nitrous oxide, an environmental concern. The energy provided by the highly exothermic

reactions will be recovered through an efficient heat exchanger network which will allow steam

generation and preheating of tail gas for expansion to drive the plant compressors. Through

economic analysis the net-present-value was determined to be $984 million over the 20 year

plant life, with a rate of return of 12 years. Based on the plant economics, and the overall success

of the fertilizer plant, it is recommended to move into stage-gate 2.



INTRODUCTION

In order to make ammonium nitrate from natural gas several steps must be taken. Our

process is going to concentrate on the production of 3,829 tons per day of nitric acid from

ammonia which will be the feedstock for the ammonium nitrate process. The production of nitric

acid from ammonia undergoes the following process: Nitric oxide is produced by the reaction of

ammonia with oxygen over cobalt oxide catalyst, which is then oxidized to NO2. The NO2 is then

reacted with water in an absorption column to produce a nitric acid solution. Of the 3,289 tons

per day produced, 2571.2 tons will be supplied to the Ammonium Nitrate process while the rest

is sold on the open market. Ammonia is supplied by the ammonia plant at 571.5 tons per day.

Demand for nitric acid increased by 6.5% a year from 2002 to 2007. More recently the

demand increase has fallen to 3% per year and is expected to do so through 2018, however

because of federal rulings for ethanol components in gasoline the demand is not expected to drop

significantly. Prices between 2002 and 2007 went from a low of $145/short ton to a high of

$290/short ton; 42° Baume (67%), bulk, free on board (FOB). The majority (76%) of nitric acid

is used in the production of ammonium nitrate and the majority of the remaining 24% is used in

explosives manufacture. The strong growth for the mature product has been due to the increased

corn prices from ethanol production and also an increase in wheat prices. In addition, natural gas

prices have dropped significantly and look to stay at a low price for the foreseeable future.

The location of the plant will be in the Northwest corner of North Dakota in the Bakken

Formation of the Williston Basin. The Bakken Formation has an estimated undiscovered volume

of 1.85 trillion cubic feet of natural gas. The benefits of this site include a feed source of natural

gas and located in the agriculturally predominant Midwest. The location will have access to rail,

road, with Interstate 94 within three hours for truck transportation, and via pipeline to the little



used upper Missouri River or the Great Lakes for transportation. Since this is part of an

integrated process for the production of ammonium nitrate fertilizers and the only one of its kind

in the upper Midwest, the plant will have an ideal location to end users.

Currently, the majority of nitric acid production in the United States is produced by using

the Ostwald Process, which uses a platinum-rhodium catalyst under a single high-pressure. The

process employed will be based on a new cobalt oxide catalyst that has shown to increase yields.

Older plants were built to use a single pressure process to produce nitric acid, however because

the absorption processes favor a higher pressure, new plants use a combination of low and higher

pressure processes to increase yield. By manufacturing nitric acid using newer technologies; this

plant can increase production efficiency and therefore higher overall yield of nitric acid at a

lower cost while decreasing emissions.



DESCRIPTION OF PROCESS

General Process:

Among the different processes for nitric acid (HNO3) production the Ostwald Process in

addition to a dual-pressured system were selected for the design of the plant. The Ostwald

Process employs three major process steps for the production of nitric acid. Ammonia (NH3)

must be first oxidized to form nitrogen monoxide (NO). After ammonia oxidation, nitrogen

monoxide must be oxidized to nitrogen dioxide (NO2). The final step is absorption of nitrogen

dioxide with water (H2O) to form nitric acid. The following three chemical reactions are the

major reactions that occur in the process; oxidation of ammonia, oxidation of nitrogen monoxide,

and absorption with water (Ullman’s).

4 NH3 (g) + 5 O2 (g) → 4 NO (g) + 6 H2O (l)

2 NO (g) + O2 (g) → 2 NO2 (g)

4 NO2 (g) + O2 (g) + 2 H2O (l) → 4 HNO3 (aq)

The first reaction, oxidation of ammonia, has two undesired side reactions that take place.

The first is conversion of ammonia to nitrogen gas (N2). This particular product is of no real

concern as nitrogen is inert and a harmless gas. The second, however, leads to the formation of

nitrous oxide (N2O), more commonly known as laughing gas. As stated previously, the cobalt

oxide catalyst helps inhibit the conversion to these unwanted products. After ammonia oxidation

occurs, the temperature of the process gas exceeds 1600°F and must be cooled to form nitrogen

dioxide. A heat exchanger network allows concurrent cooling of process gases, steam generation,

and tail gas preheating. The network employs the use of a waste heat boiler, steam superheater,



shell-and-tube heat exchangers, and condensers to achieve this goal. As the process gas cools

nitrogen dioxide will readily dimerize to unwanted nitrogen tetroxide (N2O4).

After cooling, the process gas is sent to an absorption column to allow nitrogen dioxide to

be absorbed with water to produce nitric acid. An adequate amount of make-up water is used to

ensure that the product requirements of 63% acid by weight are met.

Detailed Process:

The following detailed process overview will reference the process flow diagram that can

be found in the appropriate appendix section. The process begins by taking vaporous ammonia

from the back-end ammonia team at 250°F and filtering it to rid it of any particulate that may

have accumulated during transportation to the plant. Air taken from the outside at approximately

60°F is pressurized to 72.5 psia, the desired pressure for ammonia oxidation. The compressor

used is two-stage in order to reduce the chances of equipment failure due to a hot exit gas

temperature. Due to compression the air is preheated to 480°F. The air stream is split into a

primary reactant stream that will be mixed with ammonia and a secondary air stream that will be

sent to the bleacher column to strip nitrogen tetroxide out of the nitric acid formed at the

absorption stage. The primary air stream contacts the ammonia vapor reducing the overall

temperature to 420°F. An adequate amount of air contacts the ammonia to maintain a 9:1 ratio of

air to ammonia. This ratio must be met in order to prevent the ammonia from igniting.

The air-ammonia mixture is sent to the catalytic reactor to pass over the cobalt oxide bed.

The conversion of ammonia to nitrogen monoxide is highly exothermic and increases the

temperature of the gas to 1634°F. An attached waste heat boiler and steam superheater system

allow pressurized water at the saturation point to be preheated to 970°F. The generated steam is



sold to the combined heat and power design team in return for electricity. After the steam

generation phase the product gases are cooled to 824°F. No nitrogen dioxide has been formed at

this point.

Following steam generation, the process gas passes over a series of five heat exchangers.

The first heat exchanger reduces the process gas from 824°F to 748°F in addition to preheating

the tail gas of the absorption column from 125°F to 312°F. The second heat exchanger cools the

process gas to 536°F while preheating boiler feed water from 250°F to just below its saturation

point. The third heat exchanger further cools the process gas to 428°F and nitrogen monoxide

begins to convert to nitrogen dioxide and nitrogen tetroxide. The tail gas is further preheated to

478°F at this point. The fourth and fifth heat exchangers cool the process gas 356°F and 230°F

respectively against water.

After the series of heat exchangers the first condenser is met. Further conversion of

nitrogen monoxide to nitrogen dioxide and nitrogen tetroxide occurs. The condenser allows the

formation of a very weak nitric acid solution that is pumped to the appropriate tray of the

absorption column. At this point the process gas is compressed a second time to 145 psia with

the NOx laden gases of the bleacher column. As a result of compression, the process gas is heated

to 508°F. Another heat exchanger and condenser are employed to cool the process gas to 257°F

and 197°F respectively while further converting nitrogen monoxide to nitrogen dioxide. A

second weak acid stream is formed as is sent to an acid mixer to be mixed with acid formed at

the absorption column.

At the absorption column nitrogen dioxide is combined with water to form nitric acid.

The acid leaves the column at 198°F and is then combined with the acid stream from the second

condenser raising the overall temperature to 222°F. The acid stream is sent to a bleacher column



to strip out dissolved nitrogen tetroxide enabling the 63% by weight acid solution to be achieved.

Before being sent to the bleacher the stream is cooled to 127°F. The final product is sent to the

ammonium nitrate team at 123°F and 144 psia.

The tail gas of the column primarily consists of nitrogen and oxygen with trace amounts

of nitrogen monoxide, nitrogen dioxide, nitrogen tetroxide, and nitrous oxide. These NOx gases

are environmental concerns and their contents are checked against the Environmental Protection

Agency’s (EPA) parts per million (ppm) regulations in order to ensure that they do not surpass

the limit. The tail gas is first preheated against the secondary air stream from the air compressor

and as a result is heated to 125°F. It is further preheated against the process gas leaving the

ammonia burner as described above. The hot tail gas is expanded from 145 psia to atmospheric

pressure which results in the gas being cooled to 60°F and enough power generation to power the

second compressor entirely.

Catalyst:

In the Ostwald process, ammonia oxidation occurs over a catalyst. Traditionally, a 90%

platinum and 10% rhodium based gauze is placed inside the bed and ammonia and air are reacted

over the gauze.

4 NH3 (g) + 5 O2 (g) → 4 NO (g) + 6 H2O

Low pressures cause low NO yields, while high space velocities and high temperatures

give way to large catalyst losses. At $3-4 per short ton of nitric acid produced platinum losses

accrue for a large amount of the operating cost in the oxidation reactor (Joy Industries). Catalyst

entrapments are used downstream from the reactor to recollect the platinum that is washed out of

the bed. Platinum based reactors are operated from 1490-1724˚F and achieve a 93-96%



conversion to NO. Offsite storage is required for extra platinum gauzes, which must be changed

out every 3-4 months. Changing the catalyst charges requires a full plant shutdown.

Additionally, every 3-4 weeks the plant must also be shut down in order to remove rhodium

oxide deposits.

Alternatively, a cobalt oxide based catalyst may be used for the ammonia oxidation. Ali

Nadir Caglayan has developed a cobalt oxide based catalyst for use in ammonia oxidation in

nitric acid plants. This catalyst is available through the Catalyst Development Corporation and

Joy Indsturies. Currently a cobalt oxide catalyst is being used in several plants, including Incitec

Pivot’s girdler plant on Kooragang Island, Australia and Simplot Canada’s nitric acid plant in

Brandon, Manatoba.

The operating cost for the catalyst is $0.50-0.75 per short ton of nitric acid produced.

Cobalt oxide is stronger and more durable, keeping it from degrading at high temperatures and

washing away at high space velocities. A 95-98% NO conversion rate can be achieved while

operating at approximately 1550˚F. This lower operating temperature equates to less stress on

the heat exchangers. The higher conversion rate of NO means there is less N2O produced,

resulting in lower green house gas emissions for the plant. The plant may also be operated at a

lower pressure without compromising NO yield, meaning a lower pressure drop and, therefore, a

higher lifespan of the plant.

The cobalt catalyst has a lifespan of approximately a year, in which a smaller volume of

catalyst must be added to the bed. The plant does not need to be shutdown during this process,

and after approximately 6-9 years, the entire catalyst must be changed out. Because the plant

doesn’t need to be shutdown and cooled off repeatedly, there won’t be equipment failure due to

thermal cycling. There is also no rhodium oxide buildup or need for a catalyst entrapment or



offsite storage for extra catalyst. Table 3 summarizes the comparison between the two catalyst

options.

Table 3: Catalyst Comparison

Platinum-Rhodium Cobalt Oxide (Co3O4)

Cost ($/short ton of HNO3

produced)$3 - $4 $0.50 - $0.75

Lifespan 3-4 months 12 months

Downtime 4 hours to replace gauze at end of lifespan

Remove Rhodium Oxide buildup (every 3-4 weeks)

None

Conversion Efficiency 93% - 96% 95% - 98%

Operating Parameters 24-95 psi, 1490-1724 °F 0-95 psi, 1549 °F

PROCESS CONTROL



In order to operate the plant safely and maintain specific conditions such as temperature

and pressure, the plant must be properly controlled. The control of the process was broken down

into three stages; ammonia oxidation, nitrogen monoxide oxidation, and absorption. The

diagrams for these three control schemes can be found in the appendix. The primary concern of

the ammonia oxidation portion of the plant is maintaining a 9:1 ratio of air to ammonia in the

gaseous mixture. This ratio provides a mixture of 11% by volume of ammonia in air. It is

important to maintain this ratio because air and ammonia mixtures become explosive beyond a

certain threshold, roughly 15-28% (FAO). The flow rates are controlled by a three-way valve and

flow-indicator-controllers. The other important area of control in the ammonia oxidation stage is

maintaining an outlet temperature of 970°F for the generated steam as the combined heat and

power group needs to have the steam at this specified temperature for their steam turbine.

During the nitrogen monoxide stage the temperature of the process gas must be

maintained. Nitrogen monoxide conversion to nitrogen dioxide and nitrogen tetroxide is

controlled by the temperature of the process gas. By maintaining the flow of cooling water

through the numerous heat exchangers and condensers, the temperature of the process gas can be

controlled. The temperature of the process gas is compared against its requirement and the flow

rate of the cooling water is adjusted accordingly through a temperature-indicator-controller.

During the absorption stage the temperature and pressure of the column must be

controlled. As nitric acid is formed the exothermic reaction releases heat which heats the column.

Heat must be removed from the column through the use of a pump-around. Make-up water to the

column is controlled with a flow-indicator-controller as well as a feed transmitter. The liquid

levels of both the absorption and bleacher columns are controlled in order to ensure that the

process gas makes contact with the first stage in both columns. Finally, a density controller is



used after the bleacher column outlet to ensure that the product is at the required specification of

63% nitric acid by weight.

ENVIRONMENTAL CONCERNS

This serves to give a short background on the environmental concerns involved with the

production of nitric acid. Some methods available to mitigate the solid and liquid wastes and the

green house gases (GHG) produced during the process are considered for practical use in plant

operation.

Solid waste can be formed during the ammonia oxidation or any catalytic or filtration

steps employed. Catalysts must be replaced periodically due to poisoning or losses over time.

Solids can be deposited on various parts of a nitric acid plant that uses a platinum based catalyst.

The platinum recovery catchment also degrades over time, and eventually will need replacement.

Cobalt oxide is more durable, and therefore does not leave solid deposits or require a catchment

to recover catalyst loss (Joy Industries). Cobalt oxide can contaminate waterways and therefore

must be disposed of via a licensed waste management contractor when the catalyst needs

replacement (MSDS). The cartridges used for ammonia, air, and the ammonia and air mixture

filtration must be periodically replaced. Over time, the filters will collect debris and develop an

increasing pressure drop. This pressure drop will reduce the space velocity of the streams and

lowered efficiency. To avoid flow imbalances or degraded efficiencies, the filters must be

replaced and the old filters disposed of via a waste management contractor.

Following absorption, the tail gas stream is passed to a flash separator. Here, nitric acid

mist is collected to avoid corrosion of the pipelines and prevent emitting the nitric acid gas into

the atmosphere. Periodically the acid mist cups need to be emptied and disposed of via a waste

management contractor.



The Environmental Protection Agency (EPA) has strict regulations on the GHGs that

may be emitted from a nitric acid plant. These regulations are outlined in Table 1. Of main

concern is nitrous oxide (N2O) and nitrogen oxide (NOx) gases, specifically NO and NO2.

Table 1: Tail Gas Specifications:

Species LimitNOx 100-3,500 ppmvN2O 300-3,500 ppmvO2 1-4% by volume

H2O 0.3-2% by volumeN2 Balance

Start-up and shut-down periods will normally increase the NOx content of the tail gas at

the stack. This lasts for a few hours as is required for the process to reach a steady-state, or for

the NOx to be cleared from the plant. During ammonia oxidation some nitrous oxide (N2O) is

formed. Nitrous oxide formation is favored at temperatures below 932˚F. By keeping the

reactor at 1634°F, the nitrous oxide formation can be kept to a minimum.

NOx gases are formed during the condensation and cooling steps of the process. The

amount formed is dependent upon conditions (temperature and pressure) inside the ammonia

oxidation reactor and the absorber, the catalyst used, and the heat exchanger design. Increasing

the absorber pressure will yield better NOx absorption and lower emissions of NOx into

atmosphere (EPA). Several methods are employed to achieve better absorption of the NOx

gases, which will give a better efficiency and remove the need for added tail gas treatments.

After condensing and cooling the process gas, the weak nitric acid formed is removed and sent to

the top of the absorption tower, giving a higher NOx absorption. The NOx gases that were

separated are then compressed and cooled to push the equilibrium towards acid formation



(EFMA). After absorption, a bleaching column is used to purify the product. NO2 in the process

stream causes an undesired yellow or brown color. By heating and adding air, the unreacted

NOx gases can be removed and further reacted. These gases are recycled from the bleacher and

mixed with the NOx gases entering the column prior to compression. This removes the

pollutants in the product stream. The tail gas that leaves the absorber is separated to remove any

acid mist formed. This avoids corrosion of the tail gas equipment and keeps any gaseous acid

from being emitted into the atmosphere. The tail gas is then heated through the second and first

heat exchanger networks, promoting the decomposition of nitrous gases into nitrogen and

oxygen. The tail gas is then passed through an expander and emitted to the atmosphere.

Nitrous oxide (N2O) is a known GHG. At this time, it is not regulated by the EPA, but it

is recognized as a major pollutant. There are three methods for controlling the N2O emissions

from a nitric acid plant.

Primary methods reduce the N2O formed during the ammonia oxidation step. For

example, an “empty” reaction chamber may be placed between the catalyst bed and the first heat

exchanger to increase the residence time. Or, an alternative catalyst (e.g. Cobalt Oxide) can be

used in the reaction chamber. When employed, these methods have been shown to an efficiency

of 70-85%.

Secondary methods reduce the N2O formed immediately after the ammonia oxidation

step. This is done through selective catalytic reduction (SCR). SCR has been shown to have up

to a 90% efficiency for reducing N2O. The second catalyst is used to promote N2O

decomposition via reaction [1] by increasing the residence time in the reactor.

Reaction 1:



2N2O(g) 2N2(g) + O2(g)

Tertiary methods reduce the N2O either upstream or downstream of the tail gas. This is

referred to as non-selective catalytic reduction (NSCR). NSCR has an efficiency of 80-98+%.

NSCR involves a reagent fuel (e.g. H2 from an ammonia plant purge) being used over a catalyst

via reaction [1]. An alternative method has SCR employed, and the tail gas in then mixed with

ammonia and reacted over a second catalyst bed via reaction [2].

Reaction 2:

3N2O(g) + 2NH3(g) 4N2(g) + 3H2O(g)

Table 2: Methods Used for GHG Control

Method Description Efficiency

Primary The amount of N2O formed during the ammonia oxidation is reduced.

70-85%

Secondary (SCR) N2O is reduced immediately after the ammonia oxidation.

up to 90%

Tertiary (NSCR) N2O is reduced either up or downstream of the tail gas.

80-98+%

ECONOMICS



Equipment, installation, and operating costs were obtained using Aspen Icarus Simulator.

The direct equipment purchasing and installation for the Nitric Acid Plant will be approximately

$348,000,000. Total equipment cost is approximately $66,000,000. Of this the largest cost comes

from the compressors at a cost of just under $25,000,000. Purchase of used equipment was

looked into, but since this nitric acid plant is one of the largest in the world, using a different

type of catalyst, and must be corrosion resistant, equipment of the proper size is not available.

The rest of the installation costs come from piping, engineering, instrumentation and electrical,

insulation, paint, and safety. Another main cost factor in Nitric Acid plant is material of

construction. The Nitric Acid is very corrosive material and it requires special type of material.

In order to prevent corrosion, SS304L (Aluminum mixed steel) should be used wherever nitric

acid contacts with.

The cost for the cobalt oxide catalyst is $476,000 compared to platinum catalyst that can

run as much as $3,000,000 for the reactor. One of the bonuses of using cobalt oxide over

platinum is the higher conversion rate of 98% with the additional benefit of being able to run for

years versus months without having to change out the catalyst. The catalyst operating costs are

reduced from $3-$4 per ton to $0.50-$0.75 per ton. This can produce a net savings of $453,530 -

$705,491 per year. The cost savings in using the cobalt oxide catalyst over platinum could pay

for itself. Catalyst lifespan is at least twelve months and the shutdown time for catalyst

replacement measured in hours instead of days. Since the turnaround time for catalyst

replacement is quick, the catalyst can be replaced during the normal plant shutdown period. This

will increase overall plant efficiency just by the nitric acid plant running continuously.

The plant will have a payback in twelve years from the expected plant life of twenty

years. If this were a stand-alone plant this would be too long of a payback period, however since



this is part of a larger ammonium nitrate plant, the payback period for the overall plant is much

shorter. The economics are assuming an interest rate of 8% and annual inflation rate of 3%.

Because the first three years of the project will be spent on plant installation, production not

being slated to begin until year three, and with interest rates at historic lows, the plant installation

costs will be much lower if the project is started within the year. An internal rate of return of

23.98% will be added to the overall rate of return for the total fertilizer plant. The net present

value after the twenty year life span of the plant works out to be $984 million. Please see details

of the economics below.

COMPETING PROCESSES

Organic Fertilizers



Organic fertilizers are made from ingredients ranging from compost to manure. The

bonus of organic fertilizer is that it will not “burn” the plants they are added to. They do not

contaminate groundwater. They are also able to get rid of agricultural waste as well. Many of

the common household organic fertilizers are made from chicken manure. However, organic

fertilizers tend to have a lower nutrient ratio than inorganic fertilizers and the quality can vary

from batch to batch depending on the ingredients. Organic fertilizers have become known more

as soil amendments and do show signs of long term positive effects on the soil.

Inorganic Fertilizers

Inorganic fertilizers are more widely used in the world today. The primary reason for

their use is that they are able to provide the primary compounds plants need as nutrients. The

major bonus of them is that the nutrient levels are consistent batch to batch. This is primarily

because the feedstock is consistent. One of the downsides of inorganic fertilizer is the “burning”

of plant materials. This is caused by a buildup of salts which are what inorganic fertilizers a

made of. This is not an issue if the proper amount of fertilizer is used per square foot of soil.

The other problems that can occur are groundwater contamination and the increase of heavy

metals (EPA http://www.epa.gov/oppt/pubs/fertilizer.pdf) from the mining of phosphate ores.

Many areas of Illinois frequently have problems with nitrates and phosphorus levels in drinking

water. (Illinois State Water Survey)

The major inorganic fertilizers are nitrogen based, potassium based, and phosphorus

based. There are many variations on these fertilizers combining secondary nutrients such as

sulfur, calcium and sodium and micronutrients such as boron and metals such as iron. In

addition, there are many different combinations of the three main types and subtypes of

fertilizers. NPK fertilizers contain all three main types and can contain secondary and



micronutrients for enhanced plant growth. Through careful research, it has been shown that

nitrogen is the most important ingredient in most fertilizers because it has the quickest and most

pronounced effect. Phosphorus based fertilizers are the second most applied straight fertilizer.

Because it is used by all of the cells in a plant it is a necessary ingredient for plant life. Although

potassium is used as a straight fertilizer in many cases, it is not effective without the addition of

some nitrogen or phosphorus containing compounds. Most fertilizers are some type of NPK

fertilizer and have the percentage of nutrient by weight information in order to help with

application.

Nitric Acid

At present, although there are alternative procedures for making nitric acid, the only way

that is currently practiced industrially is by the Ostwald process. The Ostwald process involves

three primary reactions for the formation of nitric acid; oxidation of ammonia, oxidation of

nitrogen monoxide, and absorption by water.

4 NH3 (g) + 5 O2 (g) → 4 NO (g) + 6 H2O

2 NO (g) + O2 (g) → 2 NO2 (g)

4 NO2 (g) + O2 (g) + 2 H2O (l) → 4 HNO3 (aq)

Originally nitric acid was produced by the reaction of sulfuric acid and saltpeter primarily

from Chile. There was a fear though, that the rise of the world’s population and knowing the role

of nitrogen in plants that the saltpeter would soon be exhausted. This started the development of

a new way to make nitric acid commercially. For a while, an electric arc was used to remove

oxygen and nitrogen from air. This process, developed by Lord Rayleigh (John William Strutt),

was used commercially to some extent, but was only feasible where electricity was cheap. The

Wisconsin process has shown to make very low concentrations of nitric acid under high heat, and



nuclear nitrogen fixation can produce up to 15% nitric acid, but neither can compete with

ammonia oxidation economically.

RECOMMENDATIONS

The proposed nitric acid plant that would be part of a fertilizer producing complex

located at the Williston Basin in North Dakota. The plant is capable of producing 3,289 TPD of a



solution of 63% weight nitric acid and water. 2,571 TPD are provided to the downstream

ammonium nitrate team while the rest is sold to the open market. The upstream ammonia team

provides the plant with 672 TPD of ammonia which is converted to nitric acid. 1,843 TPD of

high quality steam (1250 psi and 970°F) is generated and sold to the combined heat and power

team in exchange for electricity. A cobalt oxide catalyst was chosen over platinum for its

economic and environmental benefits. Costing roughly a quarter of that of platinum per ton of

nitric acid produced and its long lifespan provide huge savings. The added benefit of inhibiting

the conversion of ammonia to nitrous oxide saves money in purchasing equipment for tail gas

treatment.

The proposed nitric acid plant has an expected lifespan of 20 years and would result in a

profit of roughly $984 million. The payback period of 7 years is fantastic and the plant would be

worth building even as a standalone unit. The nitric acid plant is a small portion of the overall

fertilizer complex and is worth the initial investment of roughly $348 million. The fertilizer

complex as a whole is estimated to make roughly $7 billion after its full lifespan. As a result,

continuing further investigation into the nitric acid plant and moving to stage-gate 2 is the

recommended course of action. Stage-gate 2 would cut down the estimation of the plant

economics from +/- 50% to a much closer approximation.

APPENDICES

DESIGN BASIS



The proposed nitric acid plant must be able to output 3,289 TPD of 63% weight solution

to meet the requirements of the entire fertilizer plant. The nitric acid solution at the end of the

process contains 2,072 short tons of nitric acid and the rest water. 2,571 TPD are provided to the

downstream ammonium nitrate team while the rest is sold to the open market. The upstream

ammonia team provides the plant with 572 TPD of ammonia at 250°F and 72.5 psi which will

inevitably be converted to nitric acid. 1,843 TPD of high quality steam (1250 psi and 970°F)

generated in the process will be provided to the combined heat and power team in exchange for

electricity.

The plant will follow the Ostwald process, a well-known process that is currently the

industry standard for nitric acid production. The Ostwald process involves three basis steps;

ammonia oxidation to nitrogen monoxide, nitrogen monoxide oxidation to nitrogen dioxide, and

absorption of nitrogen dioxide with water to produce nitric acid. The only difference between the

proposed nitric acid plant and the industry standard is the choice of catalyst.

Currently, the most common method of ammonia oxidation is through the use of

platinum-rhodium gauze, containing 90% platinum and 10% rhodium. An ammonia and air

mixture is passed over the platinum-rhodium gauze and converts to nitrogen monoxide. The

proposed plant nitric plant, however, makes use of a recently developed cobalt oxide based

catalyst by Ali Nadir Caglayan of Tulsa, Oklahoma that is both significantly cheaper and more

environmentally friendly than platinum based catalysts. The cobalt oxide catalyst has widespread

advantages over the current platinum based catalyst. Platinum currently costs roughly $4 per

short ton of nitric acid produced while cobalt oxide is a mere $0.50 per short ton of acid (CDC).

Additionally, cobalt oxide catalysts result in a 95-98% conversion rate of ammonia to nitrogen

monoxide compared to platinum’s 93-96% (CDC). With a larger conversion to ammonia there



will be less undesired side reactions such as the formation of nitrous oxide, a greenhouse gas.

With significantly less nitrous oxide being formed at the ammonia oxidation stage,

environmental release is far lower than most nitric acid plants. The only other components of

concern for release are nitrogen monoxide, nitrogen dioxide, and nitrogen tetroxide. The plant

sufficiently treats the tail gas to ensure these emissions meet government standards. Finally, the

cobalt oxide catalyst has a much longer lifespan than that of platinum based catalysts. The

catalyst itself lasts for one year after which a volume of catalyst should be dumped into the

reactor bed for further use. The bed will need to be fully replaced after six years. Platinum

catalysts have a much shorter lifespan of 3-4 months and require storage for extra gauzes. With

platinum catalysts the plant must be shutdown periodically for catalyst replacement and removal

of rhodium oxide deposits.

BLOCK FLOW DIAGRAM

The overall ammonia-based fertilizer complex can be seen below. The nitric acid plant

that the group is responsible is highlighted in pink. It can be seen that our feedstock is received



from the bank end ammonia team while our products are sold to the ammonium nitrate team as

well as the open market.

Figure 1: Fertilizer Complex Block Flow Diagram



Figure 2: Nitric Acid Plant Block Flow Diagram



PROCESS FLOW DIAGRAM

Figure 3: Nitric Acid Plant Process Flow Diagram



MATERIAL BALANCE

Stream numbres correspond to those indicated on process flow diagram.

Table 3: Ammonia Oxidation: Streams (1) through (6)

Component Mass Flow STREAM 1 2 3 4 5 6

H2O LB/HR 0 0 0 0 0.00E+00 0

HNO3 LB/HR 0 0 0 0 0 0

NO2 LB/HR 0 0 0 0 0 0

NO LB/HR 0 0.00E+00 0.00E+00 0 0 0.00E+00

N2O4 LB/HR 0 0.00E+00 0.00E+00 0 0 0.00E+00

O2 LB/HR 0 2.01E+05 2.01E+05 1.77E+05 23331.3 1.77E+05

N2 LB/HR 0 6.61E+05 6.61E+05 5.84E+05 76835.37 5.84E+05

H3N LB/HR 47625 0 0 0 0 47625

N2O LB/HR 0 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

Mass Flow LB/HR 47625 8.62E+05 8.62E+05 7.62E+05 1.00E+05 8.10E+05

Volume Flow CUFT/HR 8225.483 1.13E+07 4.16E+06 3.68E+06 4.84E+05 3.81E+06

Temperature F 250 60 480.1289 480.1289 480.1289 419.9874

Pressure PSIA 72.876 14.69595 72.51887 72.51887 72.51887 72.51887

Tables 4 and 5: Nitrogen Monoxide Oxidation: Streams (7) through (18)


H2O LB/HR 75568.07 75568.07 75568.07 75568.07 75568.07 75568.07

HNO3 LB/HR 0 0 0 0 0 0

NO2 LB/HR 0 0 0 27736.82 53292.28 67496.5

NO LB/HR 82232.27 82232.27 82232.27 64141.17 47464.46 38202.91

N2O4 LB/HR 0.00E+00 0.00E+00 0.00E+00 5.33E-01 1.39E+01 9.49E+00

O2 LB/HR 66406.46 66406.46 66406.46 56760.21 47868.12 42929.82

N2 LB/HR 5.85E+05 5.85E+05 5.85E+05 5.85E+05 5.85E+05 5.85E+05

H3N LB/HR 0 0 0 0 0 0

N2O LB/HR 3.08E+02 3.08E+02 3.08E+02 3.08E+02 3.08E+02 3.08E+02

Mass Flow LB/HR 8.10E+05 8.10E+05 8.10E+05 8.10E+05 8.10E+05 8.10E+05

Volume Flow CUFT/HR 6.32E+06 4.96E+06 4.96E+06 4.43E+06 4.09E+06 3.49E+06

Temperature F 824 747.58 536 428 356 230

Pressure PSIA 65.26698 64.83165 64.54179 63.67157 62.72882 61.78608


H2O LB/HR 42179.24 31819.43 1.44E+05 1.44E+05 55401.07 1.16E+05

HNO3 LB/HR 0 10978.75 519.6035 583.2365 1.55E+05 7425.028

NO2 LB/HR 72961.4 0 73158.98 86085.13 169.6764 29.61298

NO LB/HR 23671.75 0 23671.75 23686.75 38024.33 0

N2O4 LB/HR 8.81E+03 0 1.40E+04 1.05E+03 2.61E+03 2630.171

O2 LB/HR 33787.96 0 57119.26 57119.17 23967.95 0

N2 LB/HR 5.85E+05 0 6.62E+05 6.62E+05 6.62E+05 0



H3N LB/HR 0 0 0 0 0 0

N2O LB/HR 3.08E+02 0.00E+00 3.08E+02 3.08E+02 3.08E+02 0.00E+00

Mass Flow LB/HR 7.67E+05 42798.17 9.74E+05 9.74E+05 9.37E+05 1.26E+05

Volume Flow CUFT/HR 3.33E+06 655.4346 2.58E+06 1.90E+06 1.36E+06 2.10E+03

Temperature F 246.2 179.3414 508.4646 257 197.492 249.512

Pressure PSIA 60.91585 145.0377 145.0377 144.3125 143.5874 143.5874

Table 6: Acid Formation: Streams (19) through (22)

Component Mass Flow STREAM 19 20 21 22

H2O LB/HR 87133.28 2.03E+05 2.03E+05 1.01E+05

HNO3 LB/HR 1.66E+05 1.73E+05 1.73E+05 1.73E+05

NO2 LB/HR 167.9797 197.5826 197.5826 1.98E-04

NO LB/HR 0 0 0 0

N2O4 LB/HR 2611.173 5241.625 5241.625 0

O2 LB/HR 0 0 0 0

N2 LB/HR 0 0 0 19.9772

H3N LB/HR 0 0 0 0

N2O LB/HR 0.00E+00 0 0 0

Mass Flow LB/HR 2.56E+05 3.81E+05 3.81E+05 2.74E+05

Volume Flow CUFT/HR 3500.429 5.65E+03 5322.578 3585.532

Temperature F 198.1885 221.5714 126.68 122.7036

Pressure PSIA 143.5874 143.5874 143.5874 143.5874

Table 7: Tail Gas Treatment: Streams (23) through (27)

Component Mass Flow STREAM 23 24 25 26 27

H2O LB/HR 87.2205 87.2205 87.2205 87.2205 87.2205

HNO3 LB/HR 1.66E+00 1.66E+00 1.66E+00 1.66E+00 1.657789

NO2 LB/HR 1.696764 1.696764 3.52E+00 3.79E+00 3.787372

NO LB/HR 3.80E-04 3.80E-04 3.80E-04 3.80E-04 3.80E-04

N2O4 LB/HR 2.09E+00 2.09E+00 2.72E-01 1.63E-03 2.65E-06

O2 LB/HR 23967.95 23967.95 23967.95 23967.95 23967.95

N2 LB/HR 6.62E+05 6.62E+05 6.62E+05 6.62E+05 6.62E+05

H3N LB/HR 0 0 0 0 0

N2O LB/HR 3.08E+02 3.08E+02 3.08E+02 3.08E+02 3.08E+02

Mass Flow LB/HR 6.86E+05 6.86E+05 6.86E+05 6.86E+05 6.86E+05

Volume Flow CUFT/HR 1.05E+06 1.17E+06 1.55E+06 1.90E+06 1.44E+07

Temperature F 71.6 125.312 312.314 478.148 340.3235

Pressure PSIA 131.9843 131.2592 130.534 129.8088 14.50377



Sample Calculations:

Material BalanceBasis: 100 lbmol NH3

*NOTE: Each value will be scaled up to illustrate actual flow rates and will be indicated with green

*NOTE: Values differ from figures generated in Aspen as some side reactions were ignored for hand calculations and aspects of the process were changed as the semester progressed.

Actual NH3 Supplied to Plant: 581 TPD (68,920 lbmol), Aspen: 571.5 TPD

Air Supplied to ReactorAssume 11% v/v mixture of ammonia and air to be below lower explosive limit

Air supplied=100 lbmol N H 3

0.11=909.09 lbmol Air=8,955TPD

O2 supplied=( 909.09 lbmol Air )× 0.21=190.91 lbmol O2=2,086 TPD

N2 supplied= (909.09lbmol Air )× 0.79=718.18 lbmol N 2=6,879 TPD



Reactor Balance

NO Produced∈[ 1 ]=100 lbmol N H3×( 4 lbmol NO4 lbmol N H 3 )× 0.980=98.00lbmol NO=1,004 TPD

N 2 Produced ∈[2 ]=100 lbmol N H3 ×( 2lbmol N2

4 lbmol N H3)×0.019=0.95 lbmol N2=9TPD

N2 O Produced∈ [ 1 ]=100 lbmol N H 3×( 2 lbmol N 2O4 lbmol N H3

)× 0.001=0.05 lbmol N 2O=0.8TPD

O2 Required ¿ [1 ]=98.00lbmol NO×( 5 lbmol O2

4 lbmol NO )=122.50lbmol O2=1,338 TPD

O2 Required ¿ [2 ]=0.95lbmol N2×( 3 lbmol O2

2 lbmol N2)=1.43lbmol O2=16 TPD

O2 Required ¿ [3 ]=0.05 lbmol N2 O×( 4 lbmol O2

2lbmol N2O )=0.10 lbmolO2=1 TPD

TotalO2 Required=(120.25+1.43+0.10 )=124.03lbmol O2=1,355TPD

H 2O Produced∈[ 1 ]=122.50lbmol O2×( 6 lbmol H2 O5 lbmolO2

)=147.00 lbmol H2 O=904 TPD



H 2O Produced∈[ 2 ]=1.43 lbmolO2×(6 lbmol H 2 O3 lbmolO2

)=2.85 lbmol H 2O=18 TPD

H 2O Produced∈[ 13 ]=0.10 lbmolO2 ×( 6 lbmol H2O4 lbmol O2

)=0.15 lbmol H2 O=1TPD

Total H 2 O Produced=(147.00+2.85+0.15 )=150.00lbmol H2O=923 TPD

Unreacted O2=( 190.91−122.50lbmol O2 )=66.88 lbmol O2=731TPD

Unreacted N2= (718.18+0.95 lbmol N2 )=719.13lbmol N2=6,879 TPD

Heat Recovery: Steam Superheater, Waste-heat Boiler, Heat Exchangers, CondenserAssumption: 100% of NO converted to NO2 before condenser inlet, ignore dimerizationAssumption: 100% of water vapor condenses at condenserAssumption: 45% w/w solution of nitric acid and water is formed at condenser

N O2 Produced=98.00 lbmol NO×( 2lbmol N O2

2lbmol NO )=98.00 lbmol N O2=1,539 TPD

Total H 2 OCondensed=150.00 lbmol H2O=923TPD

H 2O Required ¿ Produce 100lbmol HN O3=100 lbmol HN O3×( 1 lbmol H 2 O2lbmol HN O3

)=50lbmol H 2O

Mass of 100lbmol HN O3=100 lbmol HN O3×( 63.01lb HN O3

1lbmol HN O3)=6 ,301 lb HN O3



Water Required¿ Dilute¿45 % ww

=( 6 ,301 lb HN O3

0.45 )−6 ,301lb HN O3=7,701 lb H2O

TotalWater for Dilution=7,701+(50 lbmol H 2 O×18.02 lb H2 O1 lbmol H 2 O )=8,602 lb H2 O

HN O3 Formed=100 lbmol HN O3×( 150 lbmol H 2 O477.48 lbmol H 2O )=31.41lbmol HN O3=675 TPD

NO Produced=31.41lbmol HN O3×( 1lbmol NO2 lbmol HN O3 )=15.71lbmol NO=161TPD

N O2Consumed=31.41lbmol HN O3×( 3 lbmol N O2

2 lbmol HN O3)=47.12 lbmol N O2=740 TPD

H 2O Consumed=31.41lbmol HN O3×( 1 lbmol H 2 O2 lbmol HN O3

)=15.71lbmol H 2O=97 TP D

H 2O Unreacted=(150−15.71lbmol H2O )=134.29lbmol H 2O=826 TPD

Oxides Entering Condenser=98.00lbmol

OxidesUnreacted ¿Form HN O3=98.00−31.41lbmol=66.59lbmol

N O2∈Outlet Gas=98.00−47.12 lbmol=50.88 lbmol N O2=799 TPD

O2 Entering Condenser=98.00 lbmol NO2

+0.05 lbmol N 2O

2+

150 lbmol H2 O2

+66.88 lbmol O2=190.91lbmol O2=2,086 TPD

O2 ExitingCondenser=190.91lbmol O2−¿

TotalOutlet Gas Neglecting H 2O=803.65lbmol

H 2O∈Gas Stream=803.65lbmol × 0.56 psi87.22 psi

=6.21 lbmol H2O=38 TPD

H 2O∈Liquid Stream=134.29−6.21 lbmol H2 O=128.09 lbmol H 2 O=788 TPD



AbsorberAssumption: Concentration of O2 in outlet gas is 2.5%Assumption: Concentration of NO in outlet gas is 0.2%

O2 Required ¿Oxidize NO ¿N O2=15.71 lbmol NO×( 1 lbmolO2

2lbmol NO )=7.85 lbmolO2=86 TPD

O2 Required ¿Oxidize NO Formed=(15.71lbmol NO+50.88 lbmol N O2)× 14=16.65lbmol O2=182 TPD

O2 Required for CompleteOxidation=16.65 – (17.88−7.85)=6.62 lbmolO2=72 TPD

Air∈TailGas=[ (2.5 ×6.62 lbmolO2 )−(2.5 ×719.13 lbmol N2 )−(100 ×6.62 lbmolO2 )]

[(2.5× 0.79 )+(2.5 ×0.21 )− (100 × 0.21 )]=132.05 lbmol

O2∈Tail Gas=(132.05 ×0.21 )−6.62lbmol O2=21.11 lbmolO2=231TPD



N 2∈TailGas=(132.05 ×0.79 )+719.13lbmol N 2=823.45 lbmol N2=7,876 TPD

NO∈TailGas=(21.11 lbmolO2+823.45 lbmol N 2) × 0.002=1.69 lbmol NO=17TPD

N 2 O∈TailGas=0.05 lbmol N 2 O=0.8 TPD

Adjusted O2∈Tail Gas=21.11 lbmolO2+1.69 lbmol NO×( 14+ 1

2 )=22.38 lbmolO2=245 TPD

H 2O∈TailGas=847.57 lbmol gas× 0.248 psi159.70 psi

=1.45 lbmol H 2O=9TPD

N Ox Absorbed=(15.71lbmol NO+50.88 lbmol N O2 )−1.69 lbmol NO=64.90 lbmol

H 2O Required ¿ form HN O3=64.90 lbmol N O2( 2 lbmol H2O4 lbmol N O2

)=32.45 lbmol H 2 O=788 TPD

HN O3 Formed=64.90lbmol N O2 ×( 4 lbmol HNO3

4 lbmol N O2)+31.41lbmol HN O3=96.31 lbmol HNO3=2,072TPD

H 2O Required ¿ Dilute ¿63 % ww

=6,068 lb HN O3−(6,068 lb HN O3× 0.63 )

0.63=3,565 lb H2 O=1,217 TPD

Process H 2O Required=(32.45+197.84+1.45−128.09−6.21 lbmol H 2 O )=97.44 lbmol H 2 O=599 TPD

ENERGY BALANCE

Sample Calculations:

*NOTE: Hand calculated energy values different slightly from ASPEN values which are given in green. ASPEN values are used for sizing specifications.

Enthalpy of Reaction

∆ H=∑ n H products−∑ m H reactants

Ammonia Oxidation

4 NH3 (g) + 5 O2 (g) → 4 NO (g) + 6 H2O (g)



∆ H=[4 (90.29 kJmol )+6(−241.82 kJ

mol )]−[4(−45.90 kJmol )+5 (0 )]=−906.16 kJ

mol

4 NH3 (g) + 3 O2 (g) → 2 N2 (g) + 6 H2O (g)

∆ H=[2 (0 )+6(−241.82 kJmol )]−[4 (−45.90 kJ

mol )+3 (0 ) ]=−1,267.32 kJmol

4 NH3 (g) + 4 O2 (g) → 2 N2O (g) + 6 H2O (g)

∆ H=[2(82.05 kJmol )+6(−241.82 kJ

mol )]−[4(−45.90 kJmol )+5 (0 )]=−1,103.22 kJ

mol

Nitrogen Monoxide Oxidation

2 NO (g) + O2 (g) → 2 NO2 (g)

∆ H =[2(33.2 kJmol )]−[2(90.29 kJ

mol )+(0 )]=−114.18 kJmol

Dimerization of Nitrogen Dioxide

2 NO2 (g) ←→ N2O4 (g)

∆ H =[9.16 kJmol ]−[2(33.2 kJ

mol )]=−57.24 kJmol

Formation of Nitric Acid

4 NO2 (g) + O2 (g) + 2 H2O (l) → 4 HNO3 (aq)



∆ H =[4 (−207 kJmol )]−[4 (33.2 kJ

mol )+(0 )+2(−285.83 kJmol

)]=−389.14 kJmol

3 NO2 (g) + H2O (l) → 2 HNO3 (aq) + NO (g)

∆ H=[2(−207 kJmol )+(90.29 kJ

mol)]−[3(33.2 kJ

mol )+(−285.83 kJmol

)]=−137.46 kJmol

Air Compressor

W =( ZRTMW ) n

n−1[(P2

P1)

n−1n −1]

❑

Stage 1

n= 11−m

, m= γ−1γ E p

, γ=Cp

C v

γ=1.4 , E p=0.76 , m=0.376 ,n=1.602

Interstage Pressure Pi=√P1 P2=¿√14.7∗72.5=32.65 psia ¿



W 1=(1 ) (519.67 R )(1.986 Btu

lbmol ∙ R)

29 lblbmol

× 1.6021.602−1

× [32.65 psia14.70 psia

1.602−11.602 −1]=33.13 Btu

lb

Interstage TemperatureT i=T 1P i

P1

m

= (519.67 R )× 32.65 psia14.70 psia

0.376

=701.51 R

Intercooler: Cool air from 242°F to 120°F

q=m Cp ∆ T=854,624 lbhr

× 0.24 Btulb∙ F

× (242−120 F )=2.502∙ 107 Btuhr

CoolingWater ℜq' d , m= qCp ∆ T

=2.502 ∙107 Btu

hr

1 Btulb∙ F

× (100−80 F )=1.25∙ 106 lb

hr=15,014 TPD

Stage 2

W 2=(1 ) (579.67 R )(1.986 Btu

lbmol ∙ R)

29 lblbmol

× 1.6021.602−1

×[72.50 psia32.65 psia

1.602−11.602 −1]=36.93 Btu

lb

Outlet TemperatureT 2=T iP2

P i

m

= (579.67 R )× 72.50 psia32.65 psia

0.376

=782.43 R

Overall

W =W 1+W 2=70.06 Btulb

P=WmEp

=70.06 Btu

lb× 854,624 lb

hr0.76

=7.87 ∙107 Btuhr

NOx Compressor



W =( ZRTMW ) n

n−1[(P2

P1)

n−1n −1]

❑

Stage 1

n= 11−m

, m= γ−1γ E p

, γ=Cp

C v

γ=1.4 , E p=0.78 , m=0.376 , n=1.602

Interstage Pressure Pi=√P1 P2=¿√72.5∗145=102.5 psia ¿

W 1=(1 ) (716.67 R )(1.986 Btu

lbmol ∙R)

29 lblbmol

× 1.6021.602−1

×[102.5 psia72.5 psia

1.602−11.602 −1]=18.17 Btu

lb

Interstage TemperatureT i=T 1P i

P1

m

= (716 R )× 102.5 psia72.5 psia

0.376

=817.67 R

Intercooler: Cool gas from 358°F to 332°F

q=m Cp ∆ T=974,249 lbhr

× 0.305 Btulb∙ F

× (358−332 F )=7.72 ∙106 Btuhr

CoolingWater ℜq' d , m= qCp ∆ T

=7.72 ∙106 Btu

hr

1 Btulb∙F

× (100−80 F )=3.86 ∙105 lb

hr=4,635 TPD

Stage 2



W 2=(1 ) (791.67 R )(1.986 Btu

lbmol ∙ R)

29 lblbmol

× 1.6021.602−1

×[ 145 psia102.5 psia

1.602−11.602 −1]=20.04 Btu

lb

Outlet TemperatureT 2=T iP2

P i

m

= (791.67 R )× 145 psia102.5 psia

0.376

=930.67 R

Overall

W =W 1+W 2=38.21 Btulb

P=WmEp

=38.21 Btu

lb× 974,249 lb

hr0.78

=4.77 ∙ 107 Btuhr

Tail Gas Expander

W❑=(1 ) (1159.67 R )(1.986 Btu

lbmol ∙ R)

29 lblbmol

× 1.6021.602−1

×[ 129.08 psia14.7 psia

1.602−11.602 −1]=56.02 Btu

lb

Outlet TemperatureT 2=(1159.67 R ) × 14.7129.08

0.376

=512.67 R

P=WmEp

=56.02 Btu

lb×686,244 lb

hr0.77

=4.99 ∙107

Pinch Analysis for Heat Exchangers



Figure 4: Pinch Analysis

Heat Exchanger Sample Calculation: Steam Generation

Hot Stream: Process Gasq=m Cp ∆ T

q=(809,575 lbhr )(0.268 Btu

lb ∙F ) (1634−824℉ )=1.76 ∙108 Btuhr

=1.96 ∙ 108 Btuhr

Cold Stream: Vaporize boiler feedwater and superheat to 970°F



m= qC p ∆T +∆ H vap+∆ H superheat

m=[ 1.76 ∙ 108 Btuhr

(0.58 Btulb ∙F ) (567.4−550 F )+970 Btu

lb+(1481−1184 Btu

lb ) ]× 24 hrday

2000 lbton

=1,681 TPD=1,843TPD

Sizing:

q=UA ∆ T LM

∆ T LM=¿¿¿

∆ T LM=(1634−970℉ )−(824−550℉ )

ln (1634−970℉)(824−550℉)

=440.60

A=1.96 ∙ 108 Btu

hr

(203 Btuft2 ∙ hr ∙℉ )(440.60)

=2,194 ft2

Sample Pump Calculation:



HP= Q ∆ P1714 ϵ

HP=(156,083 lb

hr )(15 psi)

(58.62 lbft3 )(0.1337 ft3

gal )(60 minhr ) (1714 )(0.75)

=3.87 HP

Storage Tank Sizing

Specifications: Product at 120°F and density of 1.3398 kg/L (Handymath). 3 days worth of storage with a tank capacity of 70% (tank is 70% full) 4 tanks each with a diameter of 55 ft.

ρ=(1.3398 kgL )(2.204 lb

kg )( 1 L0.304 ft3 )=83.64 lb

ft3

mTOT=(3 days )( 3,289 tonsday )=(9,867 tons )( 2,000lbs

1ton )=19,734,000 lbs

V∏ ¿=(19,734,000 lbs )( 1

83.64 lbft3 )=235,939 ft3 product ¿

V TOT=235,939 ft3

0.70=337,057 ft3 total

V TANK=337,057 ft3

4=84,264 ft3 per tank

A=π (55 ft2

)2

=2,376 ft2

H=84,264 ft3

2,376 ft2 =35.5 ft



Reactor Sizing

Specifications: Reference reactor flow = 890,826 ft3/hr, space velocity = 11,000 hr-1

Reference reactor volume = (890,826 ft3/hr)/(11,000 hr-1) = 81 ft3

Catalyst depth must be 5-6’ in length Disperse flow over three beds

V REQ' D=3,808,640 ft3

hr11,000hr−1 =346 ft3

V REACTOR=346 ft3

3=115.4 ft3

A=115.4 ft3

5.5 ft=21 ft 2

D=√ 4 (21 ft2)π

=5.17 ft



Figure 5: Vapor-Liquid Equilibrium Data

Figure 6: Additional Vapor-Liquid Equilibrium Data



Figure 7: Absorption Column Design



Figure 8: Absorption Column Design Continued



PHYSICAL PROPERTIES OF PROCESS COMPONENTS

Air

Appearance: Colorless gas

Formula: N/A

Molar Mass: 29 lb/lbmol

Density (STP): 0.0806 lb/ft^3

Standard Enthalpy of Formation: N/A

Heat Capacity (NTP): 0.24 Btu/lb-F

Melting Point: N/A

Boiling Point: N/A

Ammonia


Formula: NH3

Molar Mass: 17.031 lb/lbmol


Standard Enthalpy of Formation: -46 kJ/mol


Melting Point: -108F

Boiling Point: -28F

Nitric Acid

Appearance: Colorless to yellow liquid

Formula: HNO3



Standard Enthalpy of Formation: -207 kJ/mol

Heat Capacity:

Melting Point: -44F

Boiling Point: 181F

Nitrogen




Formula: N2



Standard Enthalpy of Formation: 0 kJ/mol

Heat Capacity: 0.25 Btu/lb-F


Boiling Point: -320.33F

Nitrogen Dioxide

Appearance: Deep orange gas

Formula: NO2



Standard Enthalpy of Formation: -33.2 kJ/mol


Melting Point: 11.84F

Boiling Point: 70F

Nitrogen Monoxide


Formula: NO



Standard Enthalpy of Formation: 90.29 kJ/mol



Boiling Point: -242F

Nitrogen Tetroxide

Appearance: Colorless gas, orange liquid



Formula: N2O4


Density (STP): 89.896 lb/ft^3 (liquid)

Standard Enthalpy of Formation: -19.5 kJ/mol


Melting Point: 11.75F

Boiling Point: 70.07F

Nitrous Oxide


Formula: N2O



Standard Enthalpy of Formation: 82.05 kJ/mol


Melting Point: -131.55F


Oxygen


Formula: O2

Molar Mass: 32 lb/lbmol


Standard Enthalpy of Formation: 0 kJ/mol


Melting Point: -361.82F


Water

Appearance: Colorless liquid

Formula: H2O





Standard Enthalpy of Formation (l): -285.83 kJ/mol

Standard Enthalpy of Formation (v): -241.818 kJ/mol

Heat Capacity (NTP): 1 Btu/lb-F

Melting Point: 32F

Boiling Point: 212F

ANNOTATED EQUIPMENT LIST

Table 8: Air Compressor SpecificationsAir Compressor



Purpose: Compress air streamStage 1 Stage 2

Work [Btu/hr] 28,313,693 Work [Btu/hr] 31,561,264Inlet Temp [°F] 60 Inlet Temp [°F] 120

Outlet Temp [°F] 242 Outlet Temp [°F] 323Inlet Pressure [psi] 14.7 Inlet Pressure [psi] 32.7

Outlet Pressure [psi] 32.7 Outlet Pressure [psi] 72.5

Table 9: NOx Compressor SpecificationsNOx Compressor

Purpose: Further compress process gas streamStage 1 Stage 2

Work [Btu/hr] 17,702,104 Work [Btu/hr] 19,523,949Inlet Temp [°F] 257 Inlet Temp [°F] 332

Outlet Temp [°F] 358 Outlet Temp [°F] 471Inlet Pressure [psi] 72.5 Inlet Pressure [psi] 102.5

Outlet Pressure [psi] 102.5 Outlet Pressure [psi] 145

Table 10: Tail Gas Expander SpecificationsTail Gas Expander

Purpose: Provide boiler feedwater to processWork [Btu/hr] Tin [°F] Tout [°F] Pin [psi] Pout [psi]

49,934,298 700 58 129 14.7

NH3 Vapor FilterPurpose: Remove particulate, such as rust, from ammonia feed

Air FilterPurpose: Remove particulate, such as rust, from air feed

Air-Ammonia MixerPurpose: Combine air and ammonia feed maintaining a 9:1 ratio

Table 11: Steam Superheater SpecificationsHeat Exchanger 1 (Steam Superheater)

Purpose: Cool process gas and generate steam from boiler feed waterHeat Duty [Btu/hr] ΔTLM U [Btu/ft2-hr-°F] Size [ft2]

196,259,489 440.60 203 2,194



Cold Side Hot SideStream Steam Stream Process Gas

Inlet Temp [°F] 550 Inlet Temp [°F] 1634Outlet Temp [°F] 970 Outlet Temp [°F] 824

Table 12: Heat Exchanger 2 SpecificationsHeat Exchanger 2

Purpose: Cool process gas and oxidize nitrogen monoxideHeat Duty [Btu/hr] ΔTLM U [Btu/ft2-hr-°F] Size [ft2]

17,300,854 609.6 5 5,676Cold Side Hot Side

Stream Tail Gas Stream Process GasInlet Temp [°F] 125.3 Inlet Temp [°F] 824

Outlet Temp [°F] 226.8 Outlet Temp [°F] 747.6




Stream Boiler Feedwater Stream Process GasInlet Temp [°F] 250 Inlet Temp [°F] 747.6

Outlet Temp [°F] 550 Outlet Temp [°F] 536




Stream Tail Gas Stream Process GasInlet Temp [°F] 226.8 Inlet Temp [°F] 617




28,416,546 327.81 28 3,096



Cold Side Hot SideStream Cooling Water Stream Process Gas

Inlet Temp [°F] 80 Inlet Temp [°F] 485.73Outlet Temp [°F] 100 Outlet Temp [°F] 356




Stream Cooling Water Stream Process GasInlet Temp [°F] 80 Inlet Temp [°F] 389.7





Stream Cooling Water Stream Process GasInlet Temp [°F] 80 Inlet Temp [°F] 378.8



Purpose: Cool weak nitric acid streamHeat Duty [Btu/hr] ΔTLM U [Btu/ft2-hr-°F] Size [ft2]




Stream Cooling Water Stream Weak HNO3

Inlet Temp [°F] 80 Inlet Temp [°F] 197.7Outlet Temp [°F] 100 Outlet Temp [°F] 126.7


Purpose: Cool secondary air streamHeat Duty [Btu/hr] ΔTLM U [Btu/ft2-hr-°F] Size [ft2]


Stream Tail Gas Stream Secondary AirInlet Temp [°F] 71.6 Inlet Temp [°F] 480


Table 20: Cooler-Condenser 1 SpecificationsCooler-Condenser 1

Purpose: Cool process gas and oxidize nitrogen monoxide, form weak acidHeat Duty [Btu/hr] ΔTLM U [Btu/ft2-hr-°F] Size [ft2]


Stream Cooling Water Stream Process GasInlet Temp [°F] 80 Inlet Temp [°F] 230

Outlet Temp [°F] 100 Outlet Temp [°F] 179.6

Table 21: Cooler-Condenser 2 SpecificationsCooler-Condenser 2

Purpose: Cool process gas from NOx compressorHeat Duty [Btu/hr] ΔTLM U [Btu/ft2-hr-°F] Size [ft2]

16,128,848 136 220 539Cold Side Hot Side

Stream Cooling Water Stream Process GasInlet Temp [°F] 80 Inlet Temp [°F] 257


Table 22: Reactor SpecificationsCatalytic Reactor

Purpose: Convert ammonia to nitrogen monoxide (3 reactors used for flow dispersion)

Tot. Flow [ft3/hr]Flow per

Reactor [ft3/hr]Tot. Vol.

[ft3]Reactor Vol. [ft3]

Length [ft]

Diameter [ft]

3,808,640 1,269,547 346 115 5.5 5.2



Waste Heat BoilerPurpose: Capture heat from reactor, used in steam generation

Steam DrumPurpose: Capture steam, used in steam generation

Table 23: Absorption Column SpecificationsAbsorption Column

Purpose: Absorb nitrogen dioxide with water to produce nitric acidLower Diameter [ft] Upper Diameter [ft] Height [ft] Stages Material

16.4 9 70 30 SS304LNOx Stage Weak Acid Stage Water Stage Tray

1 25 30 Sieve

Table 24: Bleacher Column SpecificationsBleacher Column

Purpose: Strip dissolved NOx in nitric acid against secondary air streamDiameter [ft] Height [ft] Stages Material

7 35 12 SS304L

Table 25: Pump 1 SpecificationsPump 1

Purpose: Provide boiler feedwater to processFlow [lb/hr] Flow [GPM] Density [lb/ft3] ΔP [psi] Eff. HP

156,083 332 58.62 15 0.75 3.87

Table 26: Pump 2 SpecificationsPump 2

Purpose: Recycle boiler feedwater to steam drumFlow [lb/hr] Flow [GPM] Density [lb/ft3] ΔP [psi] Eff. HP

156,083 412 47.19 10 0.75 3.21

Table 27: Pump 3 SpecificationsPump 3 (SS304L)

Purpose: Transfer weak nitric acid from first condenser to absorption columnFlow [lb/hr] Flow [GPM] Density [lb/ft3] ΔP [psi] Eff. HP

42,798 82 65.30 40 0.75 2.54

Table 28: Pump 4 Specifications



Pump 4 (SS304L)Purpose: Transfer weak nitric acid from second condenser to mixer

Flow [lb/hr] Flow [GPM] Density [lb/ft3] ΔP [psi] Eff. HP125,758 262 59.76 10 0.75 2.04


Purpose: Transfer nitric acid from absorption column to mixerFlow [lb/hr] Flow [GPM] Density [lb/ft3] ΔP [psi] Eff. HP

255,690 390 73.04 10 0.75 3.39


Purpose: Transfer nitric acid solution to bleacher columnFlow [lb/hr] Flow [GPM] Density [lb/ft3] ΔP [psi] Eff. HP

381,448 699 68.05 25 0.75 13.59


Purpose: Transfer nitric acid product to storage tankFlow [lb/hr] Flow [GPM] Density [lb/ft3] ΔP [psi] Eff. HP

274,120 447 76.45 20 0.75 6.95

Table 32: Storage Tank 1 SpecificationsStorage Tank 1

Purpose: Store nitric acid product (tank farm can hold 3 days worth of product)Volume [ft3] Diameter [ft] Height [ft] Capacity [%] Density [lb/ft3] Material

84,264 55 35.5 70 83.64 SS304L



84,264 55 35.5 70 83.64 SS304L





84,264 55 35.5 70 83.64 SS304L



84,264 55 35.5 70 83.64 SS304L

ECONOMIC EVALUATION

Table 36: Materials CostsMaterials

Material Requirement Base Cost Total Cost [per year]Air 10,344 TPD $0.00/ton $0.00Ammonia Vapor 571.5 TPD $350/ton $73,009,125Nitric Acid* (SOLD) 2,571.2 TPD $220/ton $206,467,360



Nitric Acid** (SOLD) 717.8 TPD $300/ton $78,599,100Steam (SOLD) 1,843 TPD $20/ton $13,451,491Cobalt Oxide Catalyst - $0.50/ton acid $476,454TOTAL + $225,032,372/year *Sold to Ammonium Nitrate, **Sold to Open Market

Table 37: Equipment CostsEquipment Installed Costs

Equipment CostAbsorption Column $1,000,000Bleacher Column $200,000Weak Acid Pump 1 $20,000Weak Acid Pump 2 $20,000Weak Acid Pump 3 $20,000Strong Acid Pump $55,000Product Pump $45,000Boiler Feed Pump $15,000Steam Drum Pump $15,000Air Compressor $22,000,000NO Compressor $6,700,000Tail Gas Expander $9,000,000Heat Exchangers (x8) $20,000,000Condenser 1 $140,000Condenser 2 $144,000Ammonia Burner $2,500,000Steam Drum $150,000Waste-Heat Boiler $850,000Storage Tanks (x4) $3,000,000TOTAL $65,874,000TOTAL INSTALLED COST (x5) $329,370,000

Table 38: ICARUS Installed CostsICARUS Installed Costs

Item CostEquipment (taken from above) $329,370,000Piping $1,900,000Civil $530,000Steel $100,000Instrumentation $1,000,000Electrical $2,500,000



Paint $100,000Other $4,500,000G&A Overheads $1,000,000Contingencies $7,000,000TOTAL $348,000,000

Table 39: ICARUS Yearly Operating CostsICARUS Yearly Operating Costs

Item CostOperating Labor $640,000Maintenance $905,000Supervision $200,000Operating Charges $230,000Plant Overhead $912,000TOTAL -$2,900,000/year

Table 40: Utility CostsUtilities

Utility Requirement Base Cost Total CostCooling Water 169,739 TPD $0.05/kgal $745,185/yearBoiler Feed Water 1842.67 TPD $3.50/kgal $161,793/yearProcess Water 607.1 TPD $0.75/kgal $53,305/yearElectricity 30,000 kWh $0.025/kWh $6,570,000/yearSewage - - Installed CostSteam Start-up/Misc. Use - Est. $2,000,000/yearNatural Gas Heating - Est. $5,000/yearTOTAL -$9,535,283/year

Table 41: Yearly ProfitYearly Profit

Item CostRaw Materials +$225,032,372Operating Costs -$2,900,000Utilities -$9,535,283TOTAL Est. Profit: $213,000,000/year

Table 42: Overall Plant EconomicsNPV $983,871,359



IRR 23.98%Interest Rate 8.00%Inflation Rate 3.00%Payback Period for Plant 7 years

Table 43: Net-Present Value / Internal Rate of Return Calculation (Years 0-4)Income Statement for Team FoxtrotYear 0 1 2 3 4

Capital Cost 348,000,000.00

Revenues/Annual 201,590,799.11 335,984,665.18938,488 tons Nitric Acid Solution at $220/ton 139,427,408.21 232,379,013.68

261,997 tons Nitric Acid Solution at $300/ton 53,077,972.23 88,463,287.05672,695 tons Steam at $20/ton 9,085,418.67 15,142,364.45

Expenses Loan Expense 77,448,824.31 44,510,818.57 44,510,818.57 44,510,818.57Start-Up Engineering 34,800,000.00 17,400,000.00 17,400,000.00 17,400,000.00 Equip Purchase 29,000,000.00 145,000,000.00 87,000,000.00 29,000,000.00 Plant Construction 5,800,000.00 17,400,000.00 34,800,000.00Utilities 14,052,735.00 9,368,490.00 Process Water 79,957.50 53,305.00 Cooling water 1,117,777.50 745,185.00 Process Steam 3,000,000.00 2,000,000.00 Electrical 9,855,000.00 6,570,000.00Sum of Years Depreciation 34,800,000.00 32,968,421.05 31,136,842.11 29,305,263.16Salaries and Fringes 900,000.00 927,000.00Maintenance 3% of cap cost 100,000.00 103,000.00Raw Materials 49,303,062.11 82,171,770.19Catalysts 1,000,000.00 536,248.98

Total Expenses 292,048,824.31 216,679,239.62 187,403,457.79 166,922,590.89

Income before Taxes -292,048,824.31 -216,679,239.62 14,187,341.32 169,062,074.29Taxes, 40% 0.00 0.00 74,961,383.12 66,769,036.36Income After Taxes -292,048,824.31 -216,679,239.62 -60,774,041.79 102,293,037.93Add Back Depreciation 10,000,000.00 32,968,421.05 31,136,842.11 29,305,263.16

Cash Flow From Operations -282,048,824.31 -183,710,818.57 -29,637,199.69 131,598,301.09

Cumulative Cash Flow -69,600,000.00 -351,648,824.31 -535,359,642.88 -564,996,842.57 -433,398,541.48



Table 44: Net-Present Value / Internal Rate of Return Calculation (Years 5-8)Income Statement for Team FoxtrotYear 5 6 7 8

Revenues/Annual 346,064,205.14 356,446,131.29 367,139,515.23 378,153,700.68

938,488 tons Nitric Acid Solution at $220/ton 239,350,384.09 246,530,895.61 253,926,822.48 261,544,627.16


672,695 tons Steam at $20/ton 15,596,635.38 16,064,534.45 16,546,470.48 17,042,864.59

Expenses

Loan Expense 44,510,818.57 44,510,818.57 44,510,818.57 44,510,818.57

Start-Up

Engineering Equip Purchase Plant ConstructionUtilities 9,649,544.70 9,939,031.04 10,237,201.97 10,544,318.03

Process Water 54,904.15 56,551.27 58,247.81 59,995.25

Cooling water 767,540.55 790,566.77 814,283.77 838,712.28

Process Steam 2,060,000.00 2,121,800.00 2,185,454.00 2,251,017.62

Electrical 6,767,100.00 6,970,113.00 7,179,216.39 7,394,592.88

Sum of Years Depreciation 27,473,684.21 25,642,105.26 23,810,526.32 21,978,947.37

Salaries and Fringes 954,810.00 983,454.30 1,012,957.93 1,043,346.67

Maintenance 3% of cap cost 106,090.00 109,272.70 112,550.88 115,927.41

Raw Materials 84,636,923.29 87,176,030.99 89,791,311.92 92,485,051.28

Catalysts 552,336.45 568,906.54 585,973.74 603,552.95

Total Expenses 167,884,207.22 168,929,619.41 170,061,341.33 171,281,962.27

Income before Taxes 178,179,997.92 187,516,511.88 197,078,173.90 206,871,738.41

Taxes, 40% 67,153,682.89 67,571,847.76 68,024,536.53 68,512,784.91

Income After Taxes 111,026,315.03 119,944,664.12 129,053,637.37 138,358,953.51

Add Back Depreciation 27,473,684.21 25,642,105.26 23,810,526.32 21,978,947.37

Cash Flow From Operations 138,499,999.24 145,586,769.38 152,864,163.69 160,337,900.87

Cumulative Cash Flow -294,898,542.24 -149,311,772.86 3,552,390.83 163,890,291.70




Revenues/Annual 389,498,311.71 401,183,261.06 413,218,758.89 425,615,321.66



672,695 tons Steam at $20/ton 17,554,150.53 18,080,775.05 18,623,198.30 19,181,894.25

Expenses

Loan Expense 44,510,818.57 44,510,818.57 0.00 0.00

Start-Up


Process Water 61,795.10 63,648.96 65,558.43 67,525.18

Cooling water 863,873.65 889,789.86 916,483.56 943,978.06

Process Steam 2,318,548.15 2,388,104.59 2,459,747.73 2,533,540.16

Electrical 7,616,430.67 7,844,923.59 8,080,271.30 8,322,679.43


Salaries and Fringes 1,074,647.07 1,106,886.48 1,140,093.07 1,174,295.87


Raw Materials 95,259,602.82 98,117,390.90 101,060,912.63 104,092,740.01

Catalysts 621,659.54 640,309.32 659,518.60 679,304.16

Total Expenses 172,594,149.21 174,000,649.13 130,993,472.85 132,597,171.77


Taxes, 40% 69,037,659.69 69,600,259.65 52,397,389.14 53,038,868.71




Cumulative Cash Flow 331,904,162.93 507,802,304.67 754,114,412.10 1,008,746,324.86


Revenues/Annual 438,383,781.30 451,535,294.74 465,081,353.59 479,033,794.19





672,695 tons Steam at $20/ton 19,757,351.07 20,350,071.61 20,960,573.75 21,589,390.97

Expenses

Loan Expense 0.00 0.00 0.00 0.00

Start-Up


Process Water 69,550.93 71,637.46 73,786.59 76,000.18

Cooling water 972,297.40 1,001,466.33 1,031,510.32 1,062,455.63

Process Steam 2,609,546.37 2,687,832.76 2,768,467.74 2,851,521.77

Electrical 8,572,359.82 8,829,530.61 9,094,416.53 9,367,249.03


Salaries and Fringes 1,209,524.74 1,245,810.48 1,283,184.80 1,321,680.34


Raw Materials 107,215,522.21 110,431,987.87 113,744,947.51 117,157,295.94

Catalysts 699,683.29 720,673.78 742,294.00 764,562.82

Total Expenses 134,303,929.03 136,116,836.37 138,039,078.31 140,073,934.87


Taxes, 40% 53,721,571.61 54,446,734.55 55,215,631.32 56,029,573.95




Cumulative Cash Flow 1,271,925,658.15 1,543,886,855.65 1,824,871,394.35 2,115,127,995.52

Table 47: Net-Present Value / Internal Rate of Return Calculation (Years 17-19)Income Statement for Team FoxtrotYear 17 18 19

Revenues/Annual 493,404,808.02 508,206,952.26 523,453,160.83

938,488 tons Nitric Acid Solution at $220/ton 341,256,415.89 351,494,108.36 362,038,931.62

261,997 tons Nitric Acid Solution at $300/ton 129,911,319.44 133,808,659.02 137,822,918.79

672,695 tons Steam at $20/ton 22,237,072.70 22,904,184.88 23,591,310.42



Expenses

Loan Expense 0.00 0.00 0.00

Start-Up

Engineering Equip Purchase Plant ConstructionUtilities 13,757,943.41 14,170,681.71 14,595,802.16

Process Water 78,280.19 80,628.60 83,047.45

Cooling water 1,094,329.30 1,127,159.17 1,160,973.95

Process Steam 2,937,067.43 3,025,179.45 3,115,934.83

Electrical 9,648,266.50 9,937,714.49 10,235,845.93

Sum of Years Depreciation 5,494,736.84 3,663,157.89 1,831,578.95

Salaries and Fringes 1,361,330.75 1,402,170.67 1,444,235.80

Maintenance 3% of cap cost 151,258.97 155,796.74 160,470.64

Raw Materials 120,672,014.81 124,292,175.26 128,020,940.52

Catalysts 787,499.70 811,124.69 835,458.43

Total Expenses 142,224,784.49 144,495,106.97 146,888,486.50

Income before Taxes 351,180,023.53 363,711,845.29 376,564,674.33

Taxes, 40% 56,889,913.80 57,798,042.79 58,755,394.60

Income After Taxes 294,290,109.73 305,913,802.50 317,809,279.73

Add Back Depreciation 5,494,736.84 3,663,157.89 1,831,578.95

Cash Flow From Operations 299,784,846.57 309,576,960.39 319,640,858.68

Cumulative Cash Flow 2,414,912,842.09 2,724,489,802.48 3,044,130,661.16



0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 190

50,000,000

100,000,000

150,000,000

200,000,000

250,000,000

300,000,000

350,000,000

400,000,000

450,000,000

500,000,000 Sensitivity Analysis for Nitric Acid Plant

Products

Years

USD

($)

Figure 9: Sensitivity Analysis

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 190

50,000,000

100,000,000

150,000,000

200,000,000

250,000,000

300,000,000

350,000,000

400,000,000

450,000,000

500,000,000 Total Revenues vs. Total ExpensesTotal...

Years

USD

($)

Figure 10: Total Revenues vs. Expenses



UTILITIES

A summarized table with all utility cost and requirement information can be found in the

economic evaluation section of the report.

Cooling Water

Cooling water is received from the combined heat and power group at 80 psia and 80°F.

The nitric acid plant requires 169,739 TPD of cooling water used in the heat exchanger network

and condensers for process gas cooling. All of the cooling water used is returned to CHP at

100°F.

Boiler Feed Water

Boiler feed water is received from the combined heat and power group at 1,350 psia and

250°F. 1,843 TPD of boiler feed water are required. The boiler feed water is used in the process

to both cool down the process gas and eventually be converted to 1,250 psia steam at 970°F to be

sold back to the combined heat and power team. They will then use this steam to power a steam

turbine to generate electricity for the fertilizer complex.

Process Water

Process water is received from the combined heat and power group at 114 psia and 80°F.

607 TPD of process water are required. The process water is used as make-up water in the

absorption column. The absorption column is responsible for converting nitrogen dioxide into

the nitric acid product.



Electricity

Electricity is received from the combined heat and power group. The major use of

electricity comes from the air compressor at a whopping 17 MW. The remainder of the

electricity is used for pumps, lighting, controllers, and other general areas. For estimation

purposes the plant assumes a usage of 30 MW per day with the majority used by the air

compressor.

Steam

Steam is not used in the plant, but rather generated and sold to the combined heat and

power team. The 1,843 TPD of boiler feed water is turned into 1,250 psia and 970°F steam.

Upon plant startup steam will most likely need to be used to bring the ammonia burner up to

temperature. A second option is burning hydrogen or some other gas.

Sewage

Sewage systems will need to be installed within the plant.

Natural Gas

Natural gas is received by the gas purification team. Natural gas is not used in the

process, but it would be required for heating offices and other buildings for the staff.



CONCEPTUAL CONTROL SCHEME

Figure 11: Control Scheme for Ammonia Oxidation



Figure 12: Control Scheme for Nitrogen Monoxide Oxidation



Figure 13: Control Scheme for Absorption



GENERAL PLANT LAYOUT

Figure 14: General Plant Layout



The plant was laid out with the idea of safety and ease of access in mind. The plant

offices and parking lot are located away from the process block with a road as a barrier. The

prevailing wind in the figure above blows towards the south. Within the process block,

equipment was laid out based on the location of the pipe rack in order to minimize piping costs

while remaining safe. The compressor shack is located in the southwest corner of the process

block and is accessible by two roads for ease of maintenance. Within the compressor shack are

the two process compressors as well as the tail gas expander. The three pieces of equipment are

placed in a sheltered environment in order to minimize sound and protect them from the

elements. Along the northeastern edge of the pipe rack the ammonia oxidizer reactor with

attached waste heat boiler, steam drum, and steam superheater can be found. The pieces of

equipment are located near each other to maximize heat recovery for steam generation and

minimize piping costs as the boiler feed water and steam are at 1250 psi.

The northwestern edge of the pipe rack contains the air and ammonia filters as well as the

static mixer. The southern edge of the pipe rack houses many of the process heat exchangers that

are used for boiler feed water and tail gas preheating. Each of the heat exchangers has a tube-

pulling area in order to pull bundles should maintenance on the unit be required. The condensers

and their respective pumps are located near each other to minimize piping costs as a very weak

acid is produced at this point. The brown line that surrounds the acid mixer, absorption column,

and bleacher column represents a dike. The dike is used in case of catastrophic failure of the

absorption column. The dike will ensure that the acid does not spill into the rest of the process

block. The pumps within column area are near the columns in order to minimize costs. The

material for this stronger acid is much more expensive than other parts of the plant. The

southeast corner of the process block contains the nitric acid storage area which contains surge



tanks and product holding tanks. Should the plant need to be shutdown, additional nitric acid will

be ready. The loading zone allows for products to be shipped to the market or the ammonium

nitrate plant by tanker, rail, or pipeline.

DISTRIBUTION AND END-USE ISSUES REVIEW

The hot steam output from the nitric acid production process will be sent to the combined

heat and power plant, and the bulk of the 63 weight % nitric acid solution produced will be sent

to the urea plant. Both will delivered using simple piping.

The nitric acid not required by the urea plant will be sold at market value outside of the

plant. Contacts should be made with companies that will have a use for the product now or in the

future, when the plant is operational. Nitric acid has a relatively low price per weight, which will

probably make long-distance transport and handling economically infeasible. Due to this, most

sales are expected to be to nearby firms.

The nitric acid for sale will be stored upon production in a vertical cylindrical tank with a

fixed roof. It will be transported by truck, so the tank will be located near the periphery of the

overall plant near road access. The storage tank will be fitted with proper couplings and hoses.

To prevent damage from a truck leaving the loading area with the hose attached, a breakaway

hose coupling should be used. The loading area will be the area of the plant with the highest risk

of dangerous leakage due to the potential for operator error. Operators of the loading area must

be thoroughly trained and follow strict protocols and checklists. There should also be careful

maintenance of the hoses to anticipate and prevent corrosive failure.



CONSTRAINTS REVIEW

Feedstock Definition

This process will utilize natural gas from hydraulic fracturing of shale in the Bakken

Formation of the Williston Basin in North Dakota. This natural gas will be sweetened in the gas

purification unit and sent to the Ammonia Plant where the natural gas will be converted to

99.98% pure ammonia vapor. The ammonia plant will deliver 571.5 tons of ammonia vapor per

day to the nitric acid plant. The ammonia vapor will be filtered and mixed with 9100 tons per

day of filtered air and sent to the ammonia burner.

Conversion Technology

The ammonia-air mixture is sent to the ammonia burner where by utilizing a cobalt-oxide

catalyst will be converted to nitric oxide (NO). Because this is an exothermic process, there is a

tremendous amount of heat produced. The heat that is generated will produce high pressure

steam which will be sent to the Combined Heat and Power Group for electricity generation.

Nitric oxide will then be converted primarily to nitrogen dioxide as it cools down through a

series of heat exchangers and condensers. However, there is a small amount of weak nitric acid

produced. The weak nitric acid is removed from the system and introduced to the absorption

column higher up than the nitrogen dioxide. The nitrogen dioxide is then compressed and sent to

the absorption column where it runs through a series of sieve trays counter currently to water.

During the absorption process, nitrogen dioxide and water undergo a chemical reaction that

again, generates heat. The acid is drawn out at different stages, cooled, and sent back to the

column to continue the process. The acid that eventually leaves the column is approximately



63% by weight nitric acid. At this point the nitric acid is known as “red acid” and must be

purified by the bleacher column.

Separation Technology

As stated above, during the conversion of nitric oxide to nitrogen dioxide, a small amount

of weak nitric acid is produced. Before introduction to the absorption column, the weak acid and

nitrogen dioxide must be separated. This is accomplished with the condensers. As the vapor

stream passes through the first condenser, weak nitric acid separates from the vapor stream and is

pumped to the absorption column at a higher stage. In addition, as the vapor cools even further it

is sent to a compressor and second condenser. The very weak (2-3% by weight) nitric acid

separated by the second condenser is used as make-up in nitric acid purification in the bleacher

column. The acid mixture stream is sent to the bleacher column to remove impurities. The

bleacher column consists of a stripping section and a reboiler. The acid stream is run counter

current to an air stream. The air stream absorbs impurities such as nitrogen dioxide and

dinitrogen tetraoxide from the acid mixture and is sent to the compressor.

Product Description

2289 tons per day of 63% by weight purified nitric acid leaves the bleacher column. From

here the nitric acid either enters storage or is sent directly to the ammonium nitrate group. It

should be noted that any nitric acid sent to storage should be used as quickly as possible if color

is important because as the acid sits, the acid can “yellow due to the separation of NOX. The

ammonium nitrate group will convert nitric acid, ammonia, and urea into either ammonium

nitrate or urea ammonium nitrate to be used as fertilizer for crop production.



Location Sensitivity Analysis

The nitric acid plant will be located in the Bakken Shale Deposit of the Williston Basin in

Northwestern North Dakota. The Bakken Shale Deposit lies in a relatively non-geologically

active zone, and therefore earthquakes are rare. The largest earthquake on record occurred on

July 8, 1968 and was magnitude 4.4. Should accidental release of nitric acid or vapors from the

process occur, the damage should be insignificant. The only concern would be nitric acid leakage

to the Missouri river. The effect of an accidental spill will be minimized by proper containment

and neutralization, training, and communication with the local officials. This plant has been

designed to keep emissions from the tail gas low by use of an economizer. The area of

Northwestern North Dakota is sparsely populated with the largest community being Williston

with a population of just over 13,000 residents. Any accidental spill should not adversely affect

the community there, but safety protocols have been put into practice to avoid such releases.

ESH Law Compliance

This plant’s emissions are under the USEPA regulations for air contaminants. The state

of North Dakota does not have its own EPA regulations and as such only the USEPA standards

apply. The only major pollutant is NO2, the EPA maximum allowable emissions is 53 parts per

billion. The nitric acid plant produces over 5000 parts per billion, however because the plant

utilizes tail gas treatment to power a turbine at the end of the process, the emissions fall below

EPA standards. The EPA does not currently regulate NO2 emissions, however, design has been

that there may be regulations of NO2 in the future and when regulations are implemented this

plant will be well below the limit.



Employee safety is of the utmost importance in this plant. Plant process controls are

installed in order to prevent any catastrophic accidents from occurring. The largest source of

danger is in the ammonia oxidation process. The ammonia to air ratio has to be held at under

14% in order to prevent an explosion hazard. The nitric acid plant will run at a ratio of under

11% as well as having controls to prevent higher concentrations from occurring. The plant is

designed to alarm workers to a dangerous condition first and if it is not alleviated the process

will in effect shut itself down. Workers are to be trained in all aspects of safety in regards to

nitric acid production with repeat training occurring at least annually. Should an emergency

arise, teams of first responders trained in that situation will respond immediately, while clear

communication to local emergency officials ensures the situation will be contained quickly. In

addition, weekly safety meetings with the supervisors are to be performed. Each department is to

conduct its own safety review on a monthly or sooner basis. Safety teams and the safety

committee headed by the EHS director will conduct routine safety audits to ensure the plant is in

compliance with any and all regulations.

Laws of Physics Compliance

None of the laws of thermodynamics are shown to be broken. There is no decrease in

entropy at any point. Oxidation of ammonia produces nitric oxide and heat employs the first and

second laws of thermodynamics. The heat generates steam which powers a turbine for electricity

employs the first law. Nitric oxide is oxidized in a series of heat exchangers that lowers the

temperature of the system proving the zeroth, first and second laws. Condensers separate the

streams proving the second law. Compressors add work to the system once again proving the



first and second laws to be in effect. Turbines utilize gas expansion to provide work proving the

first and second laws.

Turndown Ratio

If for some reason, the production of nitric acid needs to be slowed down the plant has

the ability to achieve a turndown ratio of 2-3:1. The main reasoning for this is the minimum

vapor velocity on the trays in the absorption column. However, if there is a complete stoppage of

production in one of the downstream processes, surge tanks will be utilized. For emergency

purposes of the downstream processes being down for a week, four 250,000 gallon storage tanks

made from 304L stainless steel will be utilized. Each tank will have a dike that will contain the

one and one half times the contents of the tank in case of a leak. In addition, there will be four

more storage tanks storage for transportation. These tanks can also be used for emergency

storage if needed.



APPLICABLE STANDARDS / SAFETY REVIEW

The safety of employees and the public are of utmost concern for a chemical production

plant. Economic and logistical concerns as detailed in this report drive the design and

construction of the plant, but safe use is the number one goal of such an operation. There are

numerous important safety precautions to be taken. Some are to be considered during equipment

design and plant layout, some will be regular actions to take during operation, and some others

are to be performed during an emergency. The following is an outline of safety matters that are

relevant to the production of nitric acid.

Environmental

A great concern for the process at hand is a catastrophic equipment failure (Perry). A

likely cause for this is a situation of thermal runaway. The two highly exothermic reactions in the

Ostwald process make unchecked heating a serious problem with severe consequences. Process

controls have been prepared to carefully monitor and regulate these reactions, and cease them

immediately if need be. They also keep the ratio of ammonia to air below a safe level. The

catalytic reactor, absorption column, bleacher, heat exchangers, and various pipes and fittings

have been designed to withstand fluctuations in operation conditions within a reasonable margin.

They will be fitted with relief valves to prevent dangerous over-pressurization. With or without

thermal runaway, equipment will fail if it is sufficiently degraded (European Fertilizer

Manufacturers' Association). It will be important to ensure that the equipment is of quality

construction, and proper materials have already been selected for each of the components to

prevent corrosion. Corrosion is important to consider because of the chemicals used in the plant.

Equipment must be tested regularly for corrosion and replaced if need be.



The total failure of a key piece of equipment will result in the release of some or all of its

contents. The plant designer must take the small chance of this occurrence seriously and

adequately prepare for the plant and employees to withstand such an event. For the components

handling gases, failure will lead to the release of dangerously hot gases. It will be important for

plant personnel to be immediately made aware of the failure and evacuate the area downwind

from the failed equipment (Towler). The absorption column and adjacent piping will contain a

liquid solution of highly reactive nitric acid, and the release of a large amount of heated nitric

acid from this section is the greatest safety concern in the entire plant. Once again, plant

personnel should be alerted, and the layout of the area should allow for immediate evacuation to

avoid contact with liquid and vapor release. A large amount of liquid, when spilled, has the

potential to travel far along the ground. Bunding should be used in this area to contain a spill

within this section of the plant, which will defend personnel as well as other equipment from

damage and harm. A thick foundation of concrete may be necessary as well to prevent

contamination of groundwater. Nitric acid itself has low flammability, but it it is still a fire

hazard. Its reactions involve exothermic oxidation, which can produce flammable vapors and

enough heat to ignite them. Equipment and support structures within reach of the ground in the

area of the absorption column should be coated with a material that can withstand fire and

insulate from high heat.

In the case of any large failure, it is vital for the public and plant employees to be

prepared. Evacuations and other emergency procedures should be planned and reviewed with

employees before the possibility of a spill. Contacts should be previously established with nearby

chemical cleanup specialists. Proper Personal Protective Equipment (PPE) should be acquired

and kept on-hand for work that must be performed immediately in the area of a spill. The PPE



required to handle a dangerous spill would be a hazardous materials suit, including protective

clothing and a breathing apparatus.

The Environmental Protection Agency details the work that must be done by a Local

Emergency Planning Committee (LEPC) (EPA). These committees are established to protect the

safety of the public near the plant, and it is especially relevant in emergency preparations. Its

tenets, as detailed by the EPA, are as follows:

“Write emergency plans to protect the public from chemical accidents;

Establish procedures to warn and, if necessary, evacuate the public in case of an

emergency;

Provide citizens and local governments with information about hazardous chemicals and

accidental releases of chemicals in their communities; and

Assist in the preparation of public reports on annual release of toxic chemicals into the

air, water, and soil.”

The light release of chemicals is a hazard for employees as well. It can be caused by an error

by a plant operator, such as leaving a sample point open, or spilling material while loading or

unloading. It can also be caused by leaks from degraded or improperly fitted equipment. Liquid-

handling areas of the plant should have ground formations to contain and direct the flow of

hazardous liquids to storage containers. Neutralization of small quantities of the nitric acid

solution can be done by slowly adding a weak base or a third-party product to the spill. Some

neutralization materials, equipment, and training for doing so should be prepared in the plant

beforehand.



Indeed, a more in-depth study of plant risks is necessary. The Occupational Safety and

Health Administration (OSHA) requires a formal process hazard assessment for the plant. A

failure-mode effect analysis, which is a discussion panel with experts in aspects of the plant, is

also recommended to ensure that all potential hazards are fully considered.

Occupational Health & Safety

The long-term well-being of plant personnel is vital to consider. OSHA in the United States

regulates this facet of plant operation, and the following are many of the things that must be

minded while constructing and operating the plant.

The dilute presence of airborne chemicals is a hazard requiring constant management

(Wells). This presence must be kept within acceptable levels by containing leaks, using proper

ventilation around work areas, and by engineering controls. OSHA allows for certain levels of

airborne chemicals, and the permitted concentrations are as follows. The terms used are defined,

followed by the concentration limits accepted by OSHA for key chemicals in the process.

PEL: Permissible Exposure Limit.

TWA: Time-Weighted Average. Defined by OSHA as "… the employee's average

airborne exposure in any 8-hour work shift of a 40-hour work week which shall not be

exceeded."

STEL: Short Term Exposure Limit.

IDLH: Immediately Dangerous to Life or Health.



Table 48: OSHA Chemical Exposure Limits (from OSHA online)

Material PEL, TWA [ppm] STEL [ppm] IDLH [ppm]NH3 25 35 300HNO3 2 4 25NO 25 - -NO2 5 - -

Another risk to be managed is that of noise. OSHA allows for a 90 decibel PEL, and it

will be imperative to maintain that for the sake of employees' ear health. There are several ways

for one to keep noise exposure within acceptable levels. They include using machinery which is

inherently low-noise, keeping bearings lubricated, erecting sound barriers, and limiting time

which personnel spend near sources of noise. If the plant exceeds a level of 85 decibels, it will be

required that an employee Hearing Conservation Program be enacted. OSHA also regulates noise

pollution of the area surrounding the plant, but that is a lesser concern due to its remote location.

There are numerous OSHA regulations regarding working spaces. There will be

numerous heated vessels and pipes throughout the plant which are burn risks. There is a zone

defined as seven feet from the ground or floor and within 15 inches of stairs and ladders which

much be protected from contact with employees. Hot components within this area must be

sufficiently insulated or guarded. Moving parts should also have guards around them. Platforms

should have guard rails, be wide enough, and have non-slip surfaces. The work area should also

be well-lit and have plenty of emergency exits.

The following is a list of components used in the process and their associated risks.Senior Design II – CHE 397 Team Foxtrot Spring 2012Calabrese, Listner, Somuncu, Sonna, Zenger Page: 84


HNO3

MSDS: http://www.inchem.org/documents/icsc/icsc/eics0183.htm

Nitric acid is a strong acid and its vapors can cause severe burns to eyes, skin, respiratory

tract, and gastrointestinal tract on contact.

Strong oxidizing agent

Adequate ventilation and engineering controls to maintain airborne levels below

workplace exposure limits.

Small spills should be neutralized with soda ash or other neutralizing materials. Reaction

will release heat and CO2 gas. Flush contaminated area with water.

Industrial spills: Evacuate personnel upwind and ventilate area

NH3

MSDS: www.airgas.com/documents/pdf/001003.pdf

Corrosive to the skin, eyes, respiratory tract, and mucous membranes.

Contact with liquid ammonia may cause chemical burns and frostbite.

Explosively mixes with air should concentration climb above 15%

NO


Nitrogen monoxide in air can convert to nitric acid producing acid rain

Can be fatal if inhaled

Causes skin irritation and severe eye irritation

Oxidizer

NO2


Strong nitrating or oxidizing agent in organic synthesis


Causes severe respiratory tract, eye, and skin burns

N2O4



MSDS: http://www.orcbs.msu.edu/msds/linde_msds/pdf/050.pdf

Strong nitrating or oxidizing agent in organic synthesis


Causes severe respiratory tract, eye, and skin burns

Cobalt Oxide Catalyst

MSDS: http://msds.orica.com/pdf/shess-en-cds-010-000034612601.pdf

May cause slight skin and eye irritation

Major Process Hazards

Equipment/Piping Failure

o Corrosion protection through use of proper nitric acid grade stainless steel.

Explosion of Air Ammonia Mixture

o Control air/ammonia mixture to ensure it is below the explosive threshold.

o Automatic closure of ammonia control valve and separate shutdown trip valve a

large ratio is measured.

Explosion of Nitrite/Nitrate Salts

o Should ammonia remain in nitrous gas steam deposits can occur. Local washing

and common operating practices easily prevent this hazard.

PROJECT COMMUNICATIONS



The project website can be reached at:http://www.che397-nitric-acid.wikispaces.com

The previous link contains all project related files and information sources used in a few zip

files. These zipped files include project presentations, expo information, research articles,

catalyst information, as well as all other working files for the project. This report itself is also

uploaded as a separate file.

SPECIAL THANKS

CHE 397 Project Supervisor: Jeffery P. Perl: UIC Department of Chemical Engineering

Project Mentor: Bill Keesom: Jacobs Engineering

Project Aid: Dennis O’Brien: Jacobs Engineering

Cobalt Oxide Catalyst Inventor: Ali Nadir Caglayan: Catalyst Development Corporation

INFORMATION SOURCES AND REFERENCES


http://www.che397-nitric-acid.wikispaces.com/


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Catalyst Development Corporation. 2003. Tulsa, Oklahoma, USA. <www.cobaltoxide.com>.

Coker, A. Ludwig’s Applied Process Design for Chemical and Petrochemical Plants: Volume 2: Distillation, Packed Towers, Petroleum Fractionation, Gas Processing and Dehydration. Burlington MA: Gulf Professional Publishing. 2007. Print

Counce, Robert and Joseph Perona. “Gaseous Nitrogen Oxide Absorption in a Sieve-Plate Column.” Industrial and Engineering Chemical Fundamentals. July 1980. Print.

EPA. Available and Emerging Technologies for Reducing Greenhouse Gas Emissions from the Nitric Acid Production Industry. U.S. Environmental Protection Agency. 2010. <http://www.epa.gov/nsr/ghgdocs/nitricacid.pdf>.

Environmental Protection Agency. “Emergency Planning and Community Right-to-Know Act Overview.” Accessed April 5th, 2012. <http://www.epa.gov/oem/content/lawsregs/epcraover.htm>

European Fertilizer Manufacturers' Association. “Best Available Techniques for Pollution Prevention and Control in the European Fertilizer Industry”, booklet 2 of 8, 2000. <http://www.efma.org/documents/file/bat/BAT%20Production%20of%20Nitric%20Acid.pdf>

FAO Corporate Document Repository. Safety Operation of Anhydrous Ammonia Equipment. <http://www.fao.org/DOCREP/005/Y1936E/y1936e0f.htm>.

Glushchenko, V. and E. Kirichuk, “Mathematical Model of Absorption Columns for the Production of Nitric Acid”. International Chemical Engineering. 1982. Print

H.E. Eduljee. “Design of Sieve Tray Type Distillation Plates.“ British Chemical Engineering. 1958. Print

Handbook, 6th Edition, New York: McGraw-Hill 1984 Print

JOY Industries. The Complete Heat Transfer and Process Company. 1998.

Keesom, Bill. Personal Interview. 27 Mar. 2012



Kniel, G. E., Delmarco, K. and Petrie, J. G. (1996), Life cycle assessment applied to process design: Environmental and economic analysis and optimization of a nitric acid plant. Environ. Prog., 15: 221–228. doi: 10.1002/ep.670150410 <http://blowers.chee.arizona.edu/ChEE455-555/papers/Paper4.pdf>

Koch-Glitsch Column Sizing Program

Miller, D. “Mass Transfer in Nitric Acid Absorption.” AIChE Journal. Aug. 1987. Print.

“Nitric Acid.” Wikipedia. Wikimedia Foundation, Inc.,Valenciano et al. 16 Apr. 2012.“North Dakota Earthquake History.” Earthquake Information Bulletin, Volume 7, Number 6.,

United States Geological Survey., von Hake, Carl., Dec. 1975.

OSHA. “Safety and Health Topics: Ammonia.” Accessed April 1st, 2012. <http://www.osha.gov/dts/chemicalsampling/data/CH_218300.html>

OSHA. “Safety and Health Topics: Nitric Acid.” Accessed April 1st, 2012. <http://www.osha.gov/dts/chemicalsampling/data/CH_256600.html>

OSHA. “Safety and Health Topics: Nitric Oxide.” Accessed April 1st, 2012. <http://www.osha.gov/dts/chemicalsampling/data/CH_256600.html>

OSHA. “Safety and Health Topics: Nitrogen Dioxide.” Accessed April 1st, 2012. <http://www.osha.gov/dts/chemicalsampling/data/CH_257400.html>

Parkinson, Richard. UOP. Where Does It Go? An Introduction to the Placement of Process Equipment. 2009.

Perry, R.H. and Green, D.W. Perry's Chemical Engineers' Handbook. 7th Edition. McGraw-Hill Professional, 1997.

Peters, Max and Klaus Timmerhaus. Plant Design and Economics for Chemical Engineers. New York: McGraw-Hill, Inc., 1991. Print.

R.H. Perry and D. Green (Eds), Perry’s Chemical Engineers’

Ray, Martin and David Johnston. Chemical Engineering Design Project: A Case Study Approach. New York: Gordon Breach Science Publishers. 1989. Print.

Richard M. Pollastro. et al. 2008. Web. 23 Apr. 2012.



Smith, J. and H. Van Ness. Introduction to Chemical Engineering Thermodynamics. New York: McGraw-Hill, Inc., 1987. Print

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Suchak, N. and J. Joshi. Simulation and Optimization of NOX “Absorption System in Nitric Acid Manufacture.” AIChE Journal.June 1994. Print.

Taylor, Guy, Thomas Chilton, and Stanley Handforth. “Manufacture of Nitric Acid by the Oxidation of Ammonia.” Industrial and Engineering Chemistry.Aug. 1931. Print.

Towler, Gavin and Sinnott, Ray. Chemical Engineering Design. Butterworth-Heinemann, 2008.

“U.S. Natural Gas Wellhead Price” US Energy Information Administration. n.a. Web. Jan. 2012.

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“Williston (city), North Dakota.” State & County QuickFacts, United States Census Bureau, n.a. Web. 31-Jan-2012


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