Process for working up reaction gases during the oxidation HCI to chlorine

Process for working up the reaction gas comprising chlorine, hydrogen chloride, oxygen and water vapor produced during the oxidation of hydrogen chloride in a reactor to chlorine and water, and which may also comprise inert gases wherein,

• a) the reaction gas leaving the reactor is cooled by bringing it into contact with cooled hydrochloric acid in an injection condenser immediately upon leaving the reactor,
• b) the cooled reaction gas, together with the hydrochloric acid with which it was contacted in the injection condenser is then passed to a phase separation column,
• c) in the phase separation column, the cooled reaction gas and the hydrochloric acid with which it was contacted in the injection condenser are counter-currently directly contacted with cooled liquid hydrochloric acid, whereby the water vapor and hydrogen chloride condense to form additional liquid hydrochloric acid
• d) the uncondensed gas remaining after the countercurrent contact in the separation column is passed through a drying tower and is dried,
• e) the dried gas which then consists of chlorine, oxygen, hydrogen chloride and inert gases, if present, is passed out of the drying tower and is compressed to 1 to 30 bar by a compressor,
• f) the compressed gas is then passed through a cooled chlorine recuperator, wherein most of the chlorine remaining in the gas is liquified,
• g) the gas leaving the chlorine recuperator is passed to a post-cooling stage and a part of the gas leaving the post-cooling stage is returned to the reactor, and a part is passed into an absorber column and scrubbed therein with cooled hydrochloric acid to remove chlorine and hydrogen chloride;
• and
• h) the part of the gas which has been scrubbed in the absorber column is discharged as a purge.