Patent ID: 8680358
Filing Date: 2014-03-25
Classification: B01D,C10G

Abstract:
1. A method of integrating (i) a liquid-liquid extraction (LLE) process for producing polar hydrocarbons (HCs) from mixtures comprising polar and less polar HCs wherein the LLE process employs (1) a LLE column into which a first HC feed containing polar and less polar HCs is introduced and from which a first water-containing, less polar HC-rich stream is recovered from a top of the LLE column and from which a first solvent-rich stream containing solvent, polar HCs, minor amounts of less polar HCs, and measurable but reduced heavy HCs and polymeric materials (PMs) is withdrawn from a bottom of the LLE column, (2) an extractive stripper column (ESC) into which the first solvent-rich stream is introduced and from which a less polar HC-rich stream but containing a significant of polar HCs is withdrawn from a top of the ESC and recycled to the lower portion of the LLE column as reflux and from which a second solvent-rich stream containing solvent, polar HCs, and measurable but reduced heavy HCs and PMs which is substantially free of less polar HCs is withdrawn from a bottom of the ESC and (3) a first solvent recovery column (SRC) into which the second solvent-rich stream is introduced and from which a first polar HC-rich stream, which is substantially free of solvent and less polar HCs is withdrawn and from which a third solvent-rich stream is withdrawn from a bottom of the first SRC and (ii) an extractive distillation (ED) process for producing polar hydrocarbons (HCs) from mixtures comprising polar and less polar HCs wherein ED process employs (1) an ED column into which a second HC feed containing polar and less polar HCs is introduced and from which a second water-containing, less polar HC-rich stream is recovered from a top of the EDC and from which a fourth solvent-rich stream containing solvent, polar HCs, and measurable heavy HCs and PMs is withdrawn from a bottom of the EDC (2) a second SRC into which the fourth solvent-rich stream is introduced and from which a second polar HC-rich stream, which is substantially free of solvent and less polar HCs is recovered and from which a fifth solvent-rich stream from a bottom of the second SRC is withdrawn, which method comprises the steps of: (a) diverting the majority portion of the fifth solvent-rich stream into an upper portion of the LLE column as a selective solvent feed whereby heavy HCs are rejected by the solvent in the LLE column; (b) diverting a minor portion of the fifth solvent-rich stream into the ESC; and (c) diverting the third solvent-rich stream into the ED column, thereby removing heavy HCs and PMs from the fifth solvent-rich stream of the ED process which contains a polar HC selective solvent, measurable amounts of heavy HCs, and PMs that are generated from reactions among thermally decomposed or oxidized solvent, heavy HCs, and additives thereby preventing heavy HCs from accumulating in an otherwise closed solvent loop of the ED process due to the heavy HCs's high boiling points.