Patent CA-2125625-A1 (CA)
Title: Method for reprocessing solvent mixtures containing constituents of low volatility and apparatus suitable therefor
Inventor: MIESS GEORG-EMERICH
IPC: D01F13/00
Filed: 1994-06-10
Abstract: Abstract of the disclosure Method for reprocessing solvent mixtures containing constituents of low volatility and apparatus suitable therefor A method is described for reprocessing mixtures which contain organic solvents and constituents of low volatility and may contain water, including the measures: a) introducing the mixture into a concentration apparatus (2) of a solvent recovery system (32), b) concentrating the mixture in the said concentra-tion apparatus (2) by evaporating off a portion of a readily volatile fraction and feeding this readily volatile fraction to a separation column (10), c) conducting away at least a portion of the concen-trated mixture from the concentration apparatus (2) and  introducing  this  portion into  a  separation apparatus (7), wherein the said constituents of low volatility are separated off from the said concen-trated mixture and are ejected from the solvent recovery system (32), d) conducting away the concentrated mixture, freed from the said constituents of low volatility, from the said separation apparatus (7) and feeding the said mixture together with the readily volatile fraction from step b) to a separation column (10), e) separating  the mixture  from step d)  in  the separation column (10) into a lower-boiling fraction which is taken off over the column head (17) and a higher-boiling fraction which is removed from the column via the bottom (14), and f) conducting away at least a portion of the lower-boiling fraction obtained according to step e) and of  the higher-boiling fraction from the solvent recovery system (32).     A solvent recovery system (32) is further described for reprocessing mixtures which contain organic solvents, constituents of low volatility, in particular salts, and may contain water,  including a concentration apparatus (2), a separation apparatus (7) and a separation column (10) which are connected together and through which mass streams flow in the following manner:    A) feedline (1) which opens out into the concentra-tion apparatus  (2)  and serves for introducing a mixture into the concentration apparatus (2) of the solvent recovery system (32), B) outlet line (4) for conducting off a vaporized readily volatile fraction from the said concentra-tion apparatus (2) and for supplying this fraction to a separation column (10), C) outlet line (3) for conducting off the concen-trate comprising the higher-boiling constituents of the solvent mixture from the concentration apparatus (2), which outlet line (3) opens out into a separa-tion apparatus (7), D)  lock  (33)  for  discharging  from  the  solvent recovery  system  (32)  the  constituents  of  low volatility separated off in the separation apparatus (7), E) outflow line (8) for the concentrate purified by removal of the said said sparingly constituents in the separation apparatus (7), which outflow line opens out directly into the separation column (10) or into the outlet line (4)  for conducting off a vaporized readily volatile fraction from the concen-tration apparatus (2) and opens out together with this into the separation column (10), F) line (20) for leading off the resulting conden-sate from the separation column (10), and G) out low line (30) via which the higher-boiling fraction obtained in the separation column (10) is removed from the bottom (14) and which serves for ejecting the higher-boiling fraction from the sol-vent recovery system (32).     The method and the apparatus are suitable, in particular, for reprocessing used spinning baths.