| 摘要 |
<p>In a solvent elimination process, especially a solvent absorption process for purifying production waste air, pyrolysis gas, disposal site fermentation gas, bio gas or the like by removal of solvent vapours, the contaminated air is contacted in an absorption stage with a washing fluid, the contaminated washing fluid is subjected in a processing stage to thermal separation for recovering the pure washing fluid and, in a third stage, the liquid water/solvent mixture arising in the processing stage is subjected to water treatment, in which the solvent is separated off and the water is purified to such an extent that it can be re-used or discharged as effluent into a disposal system. In order to make the absorption in the first original stage more advantageous technologically and to allow an easier and more complete recovery of the washing fluid in the second stage, provision is made in the absorption stage that the absorption of the solvent vapours is carried out on dimethylpolysiloxane or a polyalkylene- modified siloxane oil of low oligomer content as the washing fluid. When a siloxane oil/water mixture is used, the processing of the contaminated washing fluid can be carried out in the processing stage in such a way that a water vapour rectification is possible without extraneous steam feed, with improved mass transfer. The absorption in the first stage can also be followed by an adsorption on a solid adsorbent for the recovery of low-boiling solvents (final purification) with a low water content.</p> |
