• Ammonia (NH₃)
• Oxygen (O₂)
• Platinum
• Water (H₂O)

Anhydrous ammonia and oxygen from the air is mixed, passed through and reacts with a platinum catalyst gauze to form NOx, then absorbed with water to produce nitric acid.

Capacity:            500 TPD
Shut Down:        January 2006
Design:              C&I Girdler
Concentration:   64%-67%
NOx Emission:   180 PPM

Purpose:
The purpose fo the nitric acid unit is to produce 65% strength nitric acid from raw materials and a catalyst for use in a variety of applications

Key Points:
-This facility has been producing 65% strength nitric acid since 1971
-The production of nitric acid is a continuous process and the plant produces about 170,000 tons per year
-The manufactured Nitric Acid is constantly circulated in a 2,000 ton storage tank before loading tan trucks for delivery
-Nitric acid is used in a variety of applications from fertilizer to explosives, as well as a raw material used in the manufacture of other chemical products
-There are a complete set of Spare Rotors for the Compressor
-New Tailgas Heaters (Never Installed)
-Zirconium Tube Bundle Cooler Condenser

• Ammonia from the storage tanks is transferred to the ammonia vaporizer through a magnetic filter, to the ammonia superheater through filters and into the mixer
• Air is sucked through an intake filter and silencer to the first case compressor
• The air is cooled by the air intercooler and enters the second case compressor then through a process filter and into the mixer
• Air and ammonia mix and enter the converter where it passes through a platinum/rhodium gauze which forms nitrogen oxide
• As it passes through the waste heat exchanger, nitrogen dioxides are also formed
• This process gas passes through a platinum filter for platinum recovery
• The gas then passes through the tailgas heater, cooler condenser and boiler feedwater heaters for process cooling and enters the absorption column
• The nitric oxide is oxidized to form nitrogen dioxide
• Water is introduced into the column where it absorbs the nitrogen dioxides to form nitric acid
• The acid enters the acid heater where it is heated to make the bleaching process more efficient
• The acid enters the bleacher column where it is bleached to clear color
• The acid is then cooled in the product acid cooler (this promotes less fumes and decreased corrosion in the storage area)
• Prior to the storage are the acid passes through the product platinum filter

CLICK HERE TO VIEW THE PROCESS FLOW DIAGRAM

1. The Ammonia section contains a storage tank from which the anhydrous ammonia is transferred to the vaporizer, superheater and filters.
   
2. The Process Air section contains the steam turbine, vera compressor (filter, silencer, compressor case 1, air cooler and compressor case 2), expander and process air filter for the required compressed air.
   
3. The Product Process section contains the following:
   • Mixer
     Where ammonia gas and compressed air mix
   • Converter
     Where the mixed gases react with a platinum catalyst within the converter
   • Waste Heat Exchanger & Platinum Filter
     The mixed gases continue through the waste heat exchanger, then through the platinum filter
   • Tail Gas Heater, Boiler Feedwater Heaters and Cooler Condenser
     Used to cool the process stream after passing through the platinum filter
   • Absorption Column
     The process stream then enters the absorption column where nitric acid is formed
   • Acid Heater
     The acid is heated to make the bleaching process more efficient
   • Bleaching Column
     The acid enters the bleaching column where it is bleached to a clear color
   • Product Acid Cooler
     The acid is then cooled in the product acid cooler, which promotes less fumes and decreased corrosion in the storage area
   • Product Platinum Filter
     Prior to the storage area, the acid passes through the product platinum filter
   • Storage Area
     
4. The Tailgas Treatment section contains the components to eliminate unconverted gases (nitric oxide) that were not absorbed in the absorption column.  The components in this section include:
   • The Mist Eliminator
     Which removes any liquid acid from the tailgas stream
   • Bleach Air Cooler
     Cools air from the air compressor
   • Tailgas Heater
     Reheats the tailgas before it enters the fume abater
   • Fume Abater
     Destroys and eliminates nitric oxides in the tailgas
   • Expander
     Uses the hot gases from the fume abater to drive the compressor 2^nd stage
   • Economizer
     Uses its own heat to heat and send water to the boiler
   • Stack
     Vents the cleaned gas to the atmosphere
     
5. The Process Utility section include:
   • Hydrogen, butane, instrument air, demin water, cooling tower water and equipment components that are used to product their own steam and heating/cooling from the heat made by the nitric acid process to continue the process in a complete cycle.
   • When running at mid to full rates, the nitric acid unit produces more thermal utility that it uses.  The components include the steam header, surface condenser, steam traps, heat exchanger and demin water supply
   • The deaerator receives steam and water from the above components where ti si heated and transferred to the ammonia superheater
   • The heated water flows to the ammonia vaporizer, boiler feedwater heaters A&B and to the acid heater
   • The vestibule jacket is a boiler around the converter
   • The waste heat exchanger is a boiler in line with the process stream
   • Water is heated to steam and transferred to the turbine and the excess is exported to plant utilities