ChE 397 – Team 7

Ammonium Nitrate and UAN

MentorAdam Kanyuh (UOP)

MembersTim Brown (Team Leader)Mahalet Sebhatu (Scribe)Gabriel SalamancaRami Saigh

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.

Introduction

Outline Ammonium Nitrate

(A.N.)

Design Basis◦ Inputs and Outputs◦ Environmental Review

Competing Processes◦ Nitrophosphate◦ Carnit◦ Stengel

Block Flow Diagram

Conclusion

Urea-Ammonium Nitrate (UAN)

Design Basis◦ Inputs and Outputs◦ Environmental Review

Block Flow Diagram

Conclusion

Ammonium Nitrate Production

Based on a total output of 1992.5 TPD (2165.8 TPD) of NH4NO3, dry weight• Feed streams:

• 423.9 TPD (460.8 TPD) NH3 dry weight

• 1568.3 TPD (1704.7 TPD) HNO3 dry weight• At 63% HNO3 by weight: 2481.4 TPD (2697.2 TPD)

Output streams• 920.5 TPD (1000.5 TPD) NH4NO3 dry weight

• 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: • 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

Design Basis

Design Basis

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

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

Competing Processes I

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]

Competing Processes II

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.

Competing Processes III

◦ [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

Process Selection

Block Flow Diagram (A.N.)

Urea-Ammonium Nitrate (UAN-32) 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

Utilities – Water, Electricity

Design Basis

Design Basis Environmental Review:

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]

Handling and Storage:

◦ Avoid using zinc or copper alloys in contact with UAN solution due to corrosion. Use corrosion inhibitors to prevent corrosion. [1]

Block Flow Diagram (UAN)

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.◦ 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.

Conclusion

Thank you for your time

Questions?

[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&Index=1976%20Thru%201980&Docs=&Query=&Time=&EndTime=&SearchMethod=1&TocRestrict=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=Carnit+Ammonium+Nitrate+Process&source=bl&ots=rWUhKgOFIn&sig=RzRctOgG8ZuFTLMM0Et2dE-jiAY&hl=en&sa=X&ei=CVoWT9X5KIKvgweCr_yhAw&ved=0CD0Q6AEwBA#v=onepage&q=Carnit%20Ammonium%20Nitrate%20Process&f=false

References