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Mixed Acid Processes

Acid handling requires state-of-the-art processes. For separation, purification and concentration of mixed acids, our tailor-made plants satisfy special requirements by combining most modern technology with well proven materials.

Requirements for handling and final product quality vary for each spent acid, and the final product may be reused in the originating process or even sold to other users for different applications. KBR has more than 70 years experience in safe handling of all types of spent acids and is able to conduct laboratory tests for spent acids mixtures not previously treated using one of KBR's PLINKE processes.

“We offer over 70 years of experience in safe handling of all types of spent acids and in addressing the varying requirements for handling and product quality.”

We offer separation, purification and concentration processes for sulfuric and nitric acid mixtures containing organic and volatile contaminants and also other contaminants such as additional inorganic acids like HCl and HF. For spent acids from explosives manufacturing, the KBR PLINKE portfolio of technology solutions includes stabilization and decomposition pre-treatment units. After pre-treatment, the mixed acids can be treated using different process units depending on feed composition and desired recovered acid composition and purity. 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.

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

Spent Nitration Acids

Spent acids from the following nitration processes have been successfully treated and reconcentrated using PLINKE technology:

  • Nitroester (NC, EGDN, DEGDN, NG, PETN, MTN, BTTN)
  • Nitroaromatics (NB, MNT, DNT, TNT, Picric Acid, DNAN)
  • Nitroguanidine (Nigu)
  • Nitroamine (RDX, HMX)
  • NTO
  • 2-EHN

Safe Treatment of Explosives Spent Acids

Sensitive spent acids, such as those originated from the production of nitroesters, must be stabilized for safe handling. KBR's PLINKE DEN®, NAC® and SAC® processes are used for regeneration of such spent acids by denitration of the sulfuric acid and production of high-concentration nitric and sulfuric acids for recycling. In particular, KBR's PLINKE’s proprietary high-temperature technology produces high-concentration and high-purity sulfuric acid, which can be concentrated up to even 98 wt% H2SO4 by using PLINKE’s unique SAVACO®-HT heat exchanger. The sulfuric acid can then be re-used in a variety of different applications or sold as a commercial product.

Nitrotoluene Spent Acids

KBR is the leading supplier of plants for re-concentration of nitrotoluene (NT) spent acids. In this application, a combination of regeneration of sulfuric acid and recovery of nitric acid is used in different combinations of DEN®, NAC®, NAPC® and SAC® processes, depending on raw materials and product requirements. Pre-treatment and stripping ensure safe destruction of unstable contaminants, as well as effective desorption of NOx and volatile organic compounds. As a result, pure sulfuric acid can be recycled to the nitration process.

Effluent Water with High Acid Content Production

Processes such as nitrotoluene (NT) produce washing waters with significant acid content. Depending of the overall production scheme, acid-rich waters can be treated together with spent acid in a DEN® SAC® unit or separately in a NAPC® unit to produce nitric acid or a nitric-sulfuric acid mixture at up to 68 wt% total acid concentration.

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Mixed Acid Process Opportunities

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