Variable, self-regulating permeate recycling in organophilic nanofiltration

A method of continuously separating a component from a liquid mixture using a membrane unit which comprises at least one membrane stage and is fed with the mixture as feed,

• wherein a membrane stage consists of at least of a conveying device, one or more membrane module(s) and a feed vessel upstream of the conveying device, and wherein the mixture is guided from the feed vessel by means of the conveying device as feed to the one or more membrane modules, which results in reduction of the component to be separated off, based in each case on the mixture guided to the respective membrane module, in the resulting permeate stream from this respective membrane module and enrichment in the resulting retentate stream from this respective membrane module or vice versa, wherein
• the overall permeate stream obtained from the last membrane stage is divided and a portion of the overall permeate stream, the recycled permeate, is recycled to the feed vessel and/or beyond the feed vessel but upstream of the conveying device and the other portion of the overall permeate stream, the permeate removed, is conducted out of the last membrane stage and out of the membrane unit on the permeate side, wherein the recycling of the recycled permeate to the feed vessel and/or beyond the feed vessel but upstream of the conveying device is effected not by means of a conveying device but by hydraulic means, that is, by means of a pressure differential that exists between the permeate side of the membrane unit and the suction side of the conveying device or the feed vessel.