Abstract: A process for the desalination of water in a continuous cyclical adsorptive operation utilizing a thermally regenerable ion retarding resin. The process employs a simulated moving bed scheme having only an adsorption zone, operated at a relatively low temperature, and desorption zone, operated at a relatively high temperature. Effluent is removed from the adsorption zone in two stages for each step of a cycle, a first stage wherein sufficient water is recovered for use as desorbent in the next step, and a second stage wherein the water product stream is withdrawn. Effluent is removed from the desorption zone also in two stages, a first stage wherein a relatively small portion having the composition of the feedstream is withdrawn, and a second stage where the extract stream having a high salt content is withdrawn.

Abstract: Sucrose which is found in molasses such as beet molasses or cane molasses may be selectively extracted therefrom by passing an aqueous solution of the molasses over a solid adsorbent such as activated carbon. The sucrose will be selectively adsorbed thereon and separated from the betaine and mineral salts, specifically potassium chloride, in the molasses. The sucrose is then removed from the adsorbent by treatment with a desorbent material comprising an alcohol. In applying the simulated moving bed countercurrent flow system to this separation, the presence of the alcohol in the adsorbent will seriously impede the adsorption of the sucrose. The present invention incorporates a water flush stream into such a system in a unique manner which, among other things, precludes the presence of alcohol in the adsorption zone.

Abstract: A process for separating three components from a feedstream employing an adsorbent and desorbent material which in combination have selectivities for the components in descending order of magnitude. The process uses a simulated-moving bed counter current flow system with an intermediate raffinate stream taken off the column at about the midpoint of the adsorption zone in addition to the usual extract and raffinate product streams. In a preferred embodiment the first component is para-xylene, the second component is ethyl benzene, and the third component is a mixture of meta and ortho-xylene.

Abstract: A process for separating a first component comprising meta-xylene, a second component comprising a mixture of para-xylene and ortho-xylene and a third component comprising ethyl benzene from a feedstream employing an adsorbent comprising a Y-zeolite containing sodium ions at exchangeable cationic sites and a desorbent material comprising toluene which in combination have selectivities for the first, second and third components, respectively, in descending order of magnitude. The process uses a simulated-moving bed counter current flow system with an intermediate raffinate stream taken off the column at about the midpoint of the adsorption zone in addition to the usual extract and raffinate product streams.

Abstract: A process for separating a selected component from a fluid mixture of components by employment of an ion exchange resin. Fluid flow is maintained through a column containing the adsorbent in at least three separation zones, an adsorption zone in which the selected component is adsorbed by the adsorbent, a purification zone and a desorption zone from which the selected component is displaced by a desorbent material. There is also a backflushing zone, upstream of either the feed or desorbent stream inlets, in which the direction of fluid flow is opposite the direction of flow through the three separation zones. The zones are periodically shifted through the column by advancing the input and output streams. The backflushing serves to decrease the density of the resin bed thereby controlling the pressure drop developed through that bed when it is in service as part of a separation zone.

Abstract: An improved process for separating normal paraffins from a feed stream containing a mixture of normal paraffins, isoparaffins and aromatic hydrocarbons to produce a normal paraffin product stream having a reduced concentration of contaminant aromatic hydrocarbons. The general process comprises the steps of contacting the feed stream with an adsorbent comprising a crystalline aluminosilicate wherein normal paraffins are adsorbed within the pores of the adsorbent and contaminant aromatics are adsorbed on the surface of the adsorbent and subsequently contacting the adsorbent with a desorbent material to remove both adsorbed normal paraffins and contaminant aromatics. The improvement resides in using a two-stage desorption step in which a first desorbent material contacts the adsorbent and removes surface-adsorbed aromatic contaminants and then a second desorbent material contacts the adsorbent to remove normal paraffins adsorbed within the pores of the adsorbent.