Recovery of soiled organic solvent used e.g. in dry-cleaning - using heat from solvent vapour to boil azeotropic solvent-water mixture

摘要

Soiled organic solvent is recovered by distilling a first vol. of soiled solvents to separate solvent vapour which is used to heat a second vol. of soiled solvent by indirect heat transfer. Controlled amts. of water are introduced into the second vol. to form an azeotropic mixture of water and solvent having a b.pt. lower than that of the solvent. This azeotropic mixT. is then heated to boiling by heat transfer from the solvent vapour and the solvent vapour, together with the vapour arising from the boiling azeotropic mixture, are condensed. Used for recovering clean solvent from organic solvents e.g. CCl2 = CCl2 soiled by use in a dry-cleaning process. Good heat economy is achieved using the heat from the solvent vapour to heat a further vol. of soiled solvent.