Transcript ChE 397 * Team 7

Ammonium Nitrate and UAN
Mentor
Adam Kanyuh (UOP)
Members
Tim Brown (Team Leader)
Mahalet Sebhatu (Scribe)
Gabriel Salamanca
Rami Saigh
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This plant focuses on the production of
Ammonia-Based fertilizers.
The plant will be located in the Williston,
North Dakota
Our focus is on the production of Ammonium
Nitrate (A.N.) and Urea-Ammonium Nitrate
(UAN-32)
These products are valuable in the fertilizer
industry due to their high levels of nitrogen.
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Ammonium Nitrate
(A.N.)
Design Basis
◦ Inputs and Outputs
◦ Environmental Review
Competing Processes
◦ Nitrophosphate
◦ Carnit
◦ Stengel
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Block Flow Diagram
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Conclusion
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Urea-Ammonium Nitrate
(UAN)
Design Basis
◦ Inputs and Outputs
◦ Environmental Review
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Block Flow Diagram
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Conclusion
Ammonium Nitrate Production
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Based on a total output of 1992.5 TPD (2165.8 TPD) of NH4NO3, dry weight
Feed streams:
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423.9 TPD (460.8 TPD) NH3 dry weight
1568.3 TPD (1704.7 TPD) HNO3 dry weight
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920.5 TPD (1000.5 TPD) NH4NO3 dry weight
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Split between granular and solution streams, amounts are to be determined
1072.0 TPD (1165.2 TPD) NH4NO3 dry weight
Sent to UAN process
Assumptions:
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At 63% HNO3 by weight: 2481.4 TPD (2697.2 TPD)
Output streams
100% yield
Full separation of product from waste
Red figures based on 92% operation time
The process is extremely exothermic, producing heat in excess of it’s own
required processes resulting in available heat for other processes. If the
ammonium nitrate reaches 240 degree Celsius, it has the potential to blow up.
Utilities required: Steam, Electricity, Water
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Environmental Review:
Ammonium nitrate:
Processes releasing most of
emissions are the neutralizers
(nitric acid, ammonia, and
particulates) depending on which
reactant is present in excess, but
mostly ammonia.
Ammonia emission range from
0.026 g/kg to 3.14 g/kg.
According to EPA, particulate
emission from ammonium nitrate
solutions based on an average
neutralizer capacity of 131,500
metric tons/year. [3]:
Emission point
Maximum ground level
concentration (μg/m3)
Neutralizer
539
Evaporator/concentrator
190
Cooler
16
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Nitrophosphate Process (a.k.a. Odda process)
◦ Involves acidifying phosphate rock with nitric acid to
produce calcium nitrate crystals, which later react with
NH3 to produce ammonium nitrate.
◦ Process uses many raw materials that aren’t supplied,
so it is economically unsound to run in the plant as
currently designed.
◦ This process has an addition of Carbon and Calcium,
which would be excessive to remove and extra
equipment. [4]
◦ Ca3(PO4)2 + 6 HNO3 + 12 H2O → 2 H3PO4 + 3 Ca(NO3)2 + 12 H2O
◦ Ca(NO3)2 + 2 NH3 + CO2 + H2O → 2 NH4NO3 + CaCO3
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Carnit Process
◦ Two reactors are required for this process
 A titanium reactor for the acidic solution
 A low carbon stainless steal reactor for the alkaline
solution.
◦ Process involves boilers and a falling film
evaporator made from low carbon stainless steel
◦ Unreacted nitric acid recycles to the reactor to react
with additional ammonia.
◦ Extra steps are required to produce granular
ammonium nitrate. [5]
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Stengel process
◦ Energy Efficient
◦ Relatively few pieces of equipment
◦ Recovers much of the exothermic energy and has
the potential to use it in another process.
◦ NH3(g) + HNO3 (aq)  NH4NO3 (aq) 99% yield
◦ This is the most viable option, both feed streams
can be easily provided and doesn’t produce
excessive waste.
◦ [Odda]
 Process uses many reactants that aren’t supplied, so it is
economically unsound to run in the plant as currently designed.
 This process has an addition of Carbon and Calcium, which would
be excessive to remove and extra equipment. [5]
◦ [Carnit]
 Process requires extra equipment
 Process is more complicated
 97.5% yield
◦ [Stengel]
 Process uses reactants efficiently
 Good energy recover in terms of recycled steam
 Low emissions
 99% Yield
Urea-Ammonium Nitrate (UAN-32)
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Based on Product steam of 2383.6 TPD (2590.9)
◦ Feed Streams:
 1072.0 TPD (1165.2 TPD) NH4NO3 dry weight
 831.3 TPD (903.6 TPD) CO(NH2)2 dry weight
 687.6 TPD (747.4 TPD) H2O
 May be mixed in with the two previous feeds
 Product stream
 2383.6 TPD (2590.9) UAN-32 (solution)
◦ UAN-32 is defined to have 32% nitrogen by weight
◦ Assumptions
 Well-Mixed
 No Waste Streams
 Perfect pH balance
 Dry feed steams
 Red figures based on 92% operation time
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Utilities – Water, Electricity
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Environmental Review:
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UAN:
◦ UAN solution is not explosive; however, it decomposes to noxious,
poisonous gases when exposed to high temperature.
◦ No gaseous emissions or waste arise during the non-pressure
mixing of the aqueous based components if the best available
technology is employed.
◦ pH values and temperatures must be monitored continuously.
◦ The ammonium/nitric acid levels are generally too small to cause
a major hazard. [2]
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Handling and Storage:
◦ Avoid using zinc or copper alloys in contact with UAN solution due
to corrosion. Use corrosion inhibitors to prevent corrosion. [1]
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We will use the Stengel process to manufacture A.N. on a total basis
of 1992.5 TPD.
Also include the manufacture of UAN on a basis of 2383.6 TPD by a
mixing process
All information presented today is a portion of our Report Outline.
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Design Basis
Introduction
Enviromental concerns and standards
Process Description
Block Flow Diagrams
Flow Sheet, material and energy balances, hand calculations, and
rough economics will be covered on the next presentation.
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Thank you for your time
 Questions?
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[1]http://www.irmteam.com/Product_Sheets/MSDS-uan32.pdf
[2]http://www.efma.org/documents/file/bat/BAT%20Production%20of%20Urea%20and%20Urea
%20Ammonium%20Nitrate.pdf
[3]http://nepis.epa.gov/Exe/ZyNET.exe/P100BKOD.txt?ZyActionD=ZyDocument&Client=EPA&I
ndex=1976%20Thru%201980&Docs=&Query=&Time=&EndTime=&SearchMethod=1&TocRestr
ict=n&Toc=&TocEntry=&QField=&Qfi
[4]http://www.chemeurope.com/en/encyclopedia/Nitrophosphate_process.html
[5]http://books.google.com/books?id=GP1caeWDUWkC&pg=PA47&lpg=PA47&dq=Carn
it+Ammonium+Nitrate+Process&source=bl&ots=rWUhKgOFIn&sig=RzRctOgG8ZuFTLM
M0Et2dEjiAY&hl=en&sa=X&ei=CVoWT9X5KIKvgweCr_yhAw&ved=0CD0Q6AEwBA#v=onepage&q
=Carnit%20Ammonium%20Nitrate%20Process&f=false