Patent ID: 8552247
Filing Date: 2013-10-08
Classification: B01D,C07C,C10G

Abstract:
1. A method for recovering a substantially hydrocarbon-free, water-soluble polar-hydrocarbon-selective solvent from a solvent-rich stream comprising hydrocarbons and heavy waste products, the method comprising: (a) Introducing a hydrocarbon feedstock comprising polar and non-polar hydrocarbons into an intermediate section of an extractive-distillation column, introducing a circulating polar solvent into an upper section of the column, recovering a raffinate product comprising non-polar hydrocarbons and water overhead from the column, and removing a rich solvent comprising polar solvent and polar hydrocarbons from the bottom of the column; (b) introducing the rich solvent into a rich-solvent fractionator, recovering an extract product comprising polar hydrocarbons overhead from the fractionator and a contaminated solvent from the bottom of the column; (c) dividing the contaminated solvent into a first portion and a second portion and directing the first portion to a first solvent-purification vessel containing a solid adsorbent to yield a purified solvent and a contaminated adsorbent; (d) passing a portion of the raffinate product to a second solvent-purification vessel containing contaminated adsorbent to yield purified solid adsorbent and contaminated raffinate; (e) subjecting the first solvent-purification vessel of step (c) containing contaminated adsorbent to the method of step (d) and the second solvent-purification vessel of step (d) to the method of step (c); and, (f) combining the second portion of contaminated solvent and purified solvent to provide the circulating polar solvent.