Claims
- 1. In a multiple effect evaporation process employing effects with heating jackets, for the separation and recovery of a volatile solvent and a solute from a solution thereof, derived from a solvent extraction process, the solvent having a boiling point below that of the solute, and the liquid solute containing a major portion of nonvolatile components and a minor portion of components that are volatile but higher boiling than said solvent, the improvement comprising:
- (a) passing vapor generated in any one effect of said multiple effect evaporation process, from which liquid is discharged, through a fractional distillation zone in which said vapor is countercurrently scrubbed with reflux liquid from which a scrubbed solvent vapor and liquid are discharged;
- (b) condensing, in the heating jacket of the next effect the scrubbed solvent vapor discharged from said fractional distillation zone to form a condensate;
- (c) returning a portion of said condensate to said fractional distillation zone as said reflux liquid, and recycling the remainder of said condensate to said solvent extraction process; and
- (d) combining the liquid discharged from said fractional distillation zone, comprising substantially all of said volatile components that enter said fractional distillation zone in said vapor, with liquid discharged from said any one effect.
- 2. The process as defined in claim 1 wherein, after a major portion of said solvent is separated from the solution by evaporation, the solute is substantially freed of solvent by stripping with steam, in a stripping zone, and wherein vapors from said stripping zone which comprises steam, solvent and a portion of said minor portion of said volatile components of the solute, are fractionally distilled to separate the solvent therefrom.
- 3. The process as defined in claims 1 or 2 wherein said volatile solvent comprises a hydrocarbon solvent boiling between 150.degree.-250.degree. F., said solute comprises oil, and wherein the major portion of non-volatile components of the oil comprises components boiling above 500.degree. F. and the minor portion of components that are volatile but higher boiling that said solvent comprises components boiling between 400.degree.-500.degree. F.
Parent Case Info
This is a division, of application Ser. No. 905,861 filed May 15, 1978 now U.S. Pat. No. 4,167,470.
US Referenced Citations (7)
Divisions (1)
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Number |
Date |
Country |
Parent |
905861 |
May 1978 |
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