High efficiency continuous separation process

Claim 1

A process for separating an extract component from a raffinate component contained in a feed mixture comprising the steps of: (a) maintaining a unidirectional fluid flow system through a series of separating units in which said components have differential rates of travel due to selective retardation or acceleration of each of said components in each of said units, each of said units having a fluid inlet and a fluid outlet; (b) passing said feed mixture into one of said fluid inlets and a displacement fluid into another of said fluid inlets, said displacement fluid being capable of displacing said components from said separating units; (c) establishing within a system comprising said fluid flow system a component concentration distribution, zones of which comprise, sequentially, the highest purity displacement fluid (zone I), extract component diluted with displacement fluid (zone II), concentrated extract component (zone III), extract and raffinate component mixture with the extract component being the major component (zone IV), extract and raffinate component mixture with the raffinate component being the major component (zone V), concentrated raffinate component (zone VI), and displacement fluid diluted with raffinate component (zone VII), each of said zones II, IV, V and VII having associated with it one of said fluid inlets and one of said fluid outlets, zone I having the fluid inlet for displacement fluid associated with it and each of zones III and VI having associated with it a fluid outlet, said feed mixture being passed through a fluid inlet the locus of which is at least proximate to the point on said component concentration of distribution where the relative proportions of the extract and raffinate components are the same as that occurring in the feed mixture; (d) withdrawing an extract stream comprising the entire flow from the fluid outlet of zone III, and withdrawing a raffinate stream comprising the entire flow from the fluid outlet of zone VI; (e) passing the entire stream from each of the fluid outlets of said zones II, IV, V and VII to a corresponding fluid inlet, the locuses of each said outlet and corresponding inlet being within the same zone of said component concentration distribution; and (f) periodically simultaneously effecting the following shifting of said inlets and outlets: the feed mixture fluid inlet to what prior to the shift was the inlet of zone V, the inlet of zone V to what had been the inlet of zone VII, the inlet of zone VII to what had been the inlet of zone I, the inlet of zone I to what had been the inlet of zone II, the inlet of zone II to what had been the inlet of zone IV, the inlet of zone IV to what had been the feed mixture inlet, the outlet of zone II to what had been the outlet of zone III, the outlet of zone III to what had been the outlet of zone IV, the outlet of zone IV to what had been the outlet of zone V, the outlet of zone V to what had been the outlet of zone VI, and the outlet of zone VI to what had been the outlet of zone VII, and the outlet of zone VII to what had been the outlet of zone II, said shifting being effected prior to the progression through said units of said component concentration distribution to the extent that the composition of the inlet or outlet streams to or from any zone becomes inconsistent with the desired composition of that zone.