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PLINKE: Sulfuric Acid

PLINKE's Sulfuric Acid Treatment technologies can be used for acid purification and concentration.


Typical sources of spent acids are:

  • Nitration processes such as production of MNT, DNT, TNT, NB, NCB, DNCB, NGL, DEGN, EGDN, NC, Picric Acid, etc.
  • Chemical applications as production of MEK and sulfonation
  • Production of certain dyes and pigment
  • Chlorine drying
  • Gas purification
  • Organic synthesis such as ether production

PLINKE has experience and reference plants in these applications.


Pre-Concentration is used when the Sulfuric Acid stream is fairly diluted (20-60 wt%), to bring concentration up to 70-75 wt%. Pre-Concentration is either processed at atmospheric pressure or at vacuum conditions. Different evaporator types can be used. For larger water evaporation capacities, multistep evaporator systems are often used for energy saving purposes. The vapors of one step are used as heating agent for another process step.

​Medium Concentration
This process is used to concentrate Sulfuric Acid from 70 wt% up to 85 wt%. The medium concentration of Sulfuric Acid is mainly operated at vacuum of about 80–150 mbar. At these conditions medium pressure steam can be used for heating and normal cooling water is used for condensation. In cases where higher temperatures are required, as for example for like decomposition of organic contaminants, atmospheric evaporation at operating temperature up to 250°C is possible.

​High Concentration
The PLINKE Gmbh's SAVACO® Process is used to produce high concentration Sulfuric Acid, up to 98 wt%. PLINKE developed a special heat exchanger operated with thermal oil as heating media at temperatures of up to 250°C. At these conditions, the process runs very economically at a reasonable vacuum level and very pure Sulfuric Acid is produced. If such high temperatures or concentrations are not required, other vacuum processes with steam heated heat exchangers are available.

Spent acids from different processes often contain organic and inorganic impurities. These contaminants must be removed or their concentration must be minimized in order to allow for reuse of the Sulfuric Acid. PLINKE offers different treatment processes for purification of Spent Acids which can be combined with the concentration steps. If the concentrated Sulfuric Acid product shall be of highest purification grade, the PLINKE Gmbh's SAVAPO® Process can be used; where the acid is completely evaporated and condensed and consequently free of all non-volatile compounds.

SAVACO®-HT Spent Sulfuric Acid from Chlorine Drying
In Chlorine manufacturing plants the produced Chlorine gas is dried by the means of Sulfuric Acid, which is consequently diluted. Typically, such diluted Sulfuric Acid is leaving this drying step at 75-78% and needs to be re-concentrated to 96% in order to be able to be re-used. PLINKE has available standardized sizes for concentration of such Sulfuric Acid, as the capacities are similar all around the world. PLINKE makes use of its special Thermo Oil heated heat exchanger (TO-HeX) which is not subject to corrosion and guarantees a long lifetime over decades. For further information, you can download the product flyer by clicking on the image on the right.