Method of recovering solvent from mother liquor containing non-volatile matters by heat pump system

摘要

A method of recovering a solvent from a mother liquor in a system in which the mother liquor also contains non-volatile matter, volatile solute and volatile solvent, and the solute concentration is low, in which a heat pump distilling column (first column) is so operated as to work only as a concentrating section of a distilling column by feeding a mother liquor to the column bottom of the heat pump distilling column, contact of non-volatile matter with the concentrating section is prevented and the column bottom liquor is sent to an evaporator so as to separate the non-volatile matter by the evaporator, thereafter, a vapor from the evaporator is fed to a distilling column (second column), and distillates of first and second columns and bottoms of the second column are withdrawn as the products. The procedures described above are carried out under specific operation conditions.