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Nitric Acid Concentration

Acid handling requires state-of-the-art processes. Be it concentration, purification or recovery of nitric acid, our tailor-made plants satisfy special requirements by combining the most modern technology with well proven materials.

KBR's PLINKE Nitric Acid technologies can be used for concentration, purification and recovery of nitric acid.

KBR has already supplied plants for a wide range of applications and therefore is in the position to develop tailor-made solutions, which correspond to state-of-the-art process engineering, to be applied anywhere in the world. We also develop new applications of our technology and operate a lab with pilot plants that allow us to develop and scale up such new applications very reliably and efficiently for our customers. Based on more than 70 years of experience in the field of acid treatment, KBR provides individual solutions for clients' needs.

“With more than 70 years of experience, we can offer customized solutions for every client’s needs for concentration, purification and recovery of nitric acid.”

KBR's PLINKE technologies can be used in different applications:

  • Concentration of diluted acid streams for processes, where high-concentration nitric acid is required
  • Recovery of spent nitric acid for reuse in the process or for resale
  • Removal of nitric acid from waste water for yield and/or environmental reasons

KBR designs small-scale plants, in which only a few hundred kilograms of acid per hour are recovered, up to world-scale plants.

Nitric Acid Pre-concentration NAPC®

Weak nitric acid pre-concentration NAPC® is used to concentrate acid up to about 68 wt% HNO3. The NAPC® process removes water from diluted nitric acid by rectification without the use of extractive agents. The maximum concentration by rectification is about 68 wt% nitric acid because the two components mixture of nitric acid and water forms an azeotropic mixture at that concentration level.

Nitric Acid High Concentration with Sulfuric Acid NACSAC®

NACSAC® is used to produce high-concentration nitric acid (up to 99 wt%), either from spent or fresh nitric acid. In this process, sulfuric acid serves as the extractive agent, which gets diluted in the NAC® and is reconcentrated in the attached SAC® to make a closed loop. The operating pressure of the NAC® column is atmospheric, and the respective SAC® unit is operated under vacuum. The energy requirements are usually exclusively covered by indirect heat transfer. Additional heat is recovered where possible. The SAC® unit is designed to evaporate water and to minimize losses of sulfuric acid. Condensate from SAC® is distilled water, which contains small amounts of sulfuric acid. This water may be used in the associated NOx absorption or in other processes accordingly. Recovered sulfuric acid at about 85 wt% concentration is optimal for use as an extractive agent, but other concentrations can be used if desired. Instead of a closed loop with NACSAC®, NAC® can operated stand-alone using fresh feed of sulfuric acid, which will be disposed or used in other applications.

Nitric Acid High Concentration with Magnesium Nitrate Solution MAGNAC®

MAGNAC® is used to produce high-concentration nitric acid (up to 99 wt%) from fresh weak nitric acid. A magnesium nitrate solution is used as the extractive agent. The NAC® column is operated at atmospheric pressure, and the respective unit for magnesium nitrate re-concentration is operated under vacuum condition. Condensate from the magnesium nitrate brine concentrator is distilled water, which contains only traces of nitric acid. This water is often used as feed water for the production of weak nitric acid from ammonia, drastically reducing the amount of effluents to be treated and minimizing nitric acid losses. KBR's PLINKE MAGNAC® technology is the most CAPEX-efficient solution for producing high-concentration nitric acid from weak nitric acid.

Pre-treatment of Spent Acids in Stabilization Unit / Decomposer STAB

Spent acids resulting from nitration processes such as Nitrocellulose (NC), Nitroglycerine (NG), Penta (PETN), Hexogene (RDX), Octogene (HMX), NTO, 2-EHN and Nitroguanidine (NiGu) contain high levels of organics that can cause process-safety and operational issues. KBR offers treatment solutions to remove or reduce concentration of these contaminants to an acceptable level before sending to NACSAC®. All acid types are treated similarly for stabilization in a combined thermo-chemical process step, where the organic compounds are destroyed in a controlled and safe way. The treatment conditions are tailor-made for the contaminants to avoid foaming and spontaneous development of gas. The resulting acid can be stored for later disposal or can be sent for re-concentration as described above.

Bleaching of Final Product

A bleaching unit is usually applied to produce colorless, NOx-reduced concentrated Nitric Acid (up to 99% HNO3) as required by the market or downstream processes.

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Nitric Acid Concentration Opportunities

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