| 摘要 |
<p>Process for concentrating an aqueous liquid containing organic compounds which are volatile or capable of being entrained with steam and optionally sugars, characterised in that it comprises a pervaporation stage which consists in bringing the said liquid into contact with the upstream face of a membrane consisting of a water-insoluble polymer absorbing water and containing from 20 to 80% by weight of polymerised and/or grafted carboxylic acid monomer units, the carboxyl groups carried by these units being wholly or partly in salt form, and maintaining, on the side of the downstream face of the membrane, a pressure lower than the partial pressure of water vapour of the said aqueous liquid to be concentrated at the temperature at which it is brought into contact with the said upstream face, so that the water in the aqueous liquid is transferred, in preference to the said organic compounds and sugars, from the upstream face to the downstream face to obtain, on the side of this downstream face, a permeate in the form of vapour essentially free from the said organic compounds and sugars and, on the side of the upstream face, a liquid aqueous retentate enriched in the said organic compounds and sugars. This process can be employed in particular for concentrating fruit juices or musts.</p> |
