Hydrochloric Acid

High Concentration

In order to produce high concentrated Hydrochloric Acid gas with low water content, which may amount to only a few ppm, the same processes as already described in the context of the medium concentration are applied. By varying the operating conditions, an HCl-H2O mixture with 75 - 90 % HCl content is refined.

The produced vapors are cooled in stages using cooling and then chilled water and finally using brine, whereby the liquid condenses in the form of concentrated Hydrochloric Acid and HCl gas is finally obtained virtually free of water.

The condensed Hydrochloric Acid is again fed into the concentration column as a reflux. In order to achieve an even lower residual moisture content, the HCl gas may be dried using concentrated sulfuric acid.

The process is carried out either at normal atmospheric pressure or even at an excess pressure of 6 - 8 bar, for example.

Thus, in a number of cases, the compression of HCl gas in mechanical compressors may be avoided.