METHOD OF THE RECUPERATION OF THE ETHERS OF CELLULOSE FROM THE WATER SOLUTIONS BY THE ULTRAFILTRATION WITH THE IMPROVED SHIFT EFFECT Russian patent published in 2007 - IPC B01D61/14 C08B11/20 

FIELD: chemical industry; methods of extraction of ethers of cellulose from the water solutions.

SUBSTANCE: the invention is pertaining to the method of extraction of the ethers of cellulose from water solutions, in particular from the washing mediums formed in the process of the crude cellulose ethers cleaning. This method includes the following stages: (a) the passage of the water solution through the membrane system for the ultrafiltration forming the improved shift effect near to the surface of the membrane for ultrafiltration at the temperature, which is below temperature of the cellulose ether flocculation; (b) the dilution of the trapped material gained at the stage (a) with the dissolvent at the volumetric ratio between the dissolvent and the trapped material in the interval from 1:1 up to 40:1; and (c) passage of the thinned trapped material gained at the stage (b) through the membrane device for the ultrafiltration forming near to the surface of the membrane for ultrafiltration the improved shift effect at the temperature, which is below the temperature of the cellulose ether flocculation. At the stage (a) and-or (c) use the membrane the nominal value of the cutoff of the molecular mass within the limits of from 100 up to 10000 D. The average velocity of the stream of the dissolved substance at the stage of (a) and-or at the stage (c) compounds from 10 up to 100 l/m²h. Realization of the method of the invention ensures the good trapping of the cellulose ether at the high velocities of the streams through the membrane.

EFFECT: the invention ensures the good trapping of the cellulose ether at the high velocities of the streams through the membrane.

14 cl, 6 ex