Arosorb process

Arosorb process a process for the separation of aromatics from nonaromatics by adsorption on a gel from which they are recovered by desorption. 

Silica-Gel Adsorption. The Arosorb process is an aromatic adsorption process developed by the Sun Oil Co. and uses silica gel to separate aromatics from naphtha reformates (54). Operating and investment costs for Arosorption were presented as follows ... 

Davis, Harper, and Weatherly have also described the Arosorb process (18),... 

The presence of hydroxyl groups imparts a degree of polarity to the surface so that molecules such as water, alcohols, phenols, and amines (which can form hydrogen bonds) and unsaturated hydrocarbons (which can form ir-complexes) are adsorbed in preference to nonpolar molecules such as saturated hydrocarbons. Because of its selectivity for aromatics silica gel was used as the adsorbent in the Arosorb process for separation of aromatics from paraffins and naphthenes but by far the most important current application is as a desiccant. 

The Cyclic adsorption process of aromatic recovery employs the same principles as the Arosorb process. However, kerosene or a pentane fraction is used as the desorbent (stripper) when treating reformate, or a light straight-run gasoline when treating kerosene. 

Recovery of Aromatics. Large amounts of benzene, toluene, and xylenes are contained in catalytic reformates and these may be recovered by (1) adsorption (Arosorb Process), (2) extractive or azeotropic distil-... 

Arosorb A process for extracting aromatic hydrocarbons from refinery streams using a solid adsorbent, either silca gel or achvated alumina. Developed by the Sun Oil Company in 1951. California Research Corporation developed a similar process. 

This technique, of the Arosorb type (Sun Oil), is uneconomic for the treatment of complex cuts from which the paraffins and naphthene are to be eliminated. Hence it has not been generalized. However, to obtain special gasolines with very low aromatics contents, similar processes are sometimes employed. The main value of adsorption emerged through the possibility it offers of separating p-xylene from its isomers in aromatic CB cuts, with high yields (see Section 4,3.3.2). 

Narrow-boiling-range feeds (150 to 225°F, see Table 21-25) are processed, and the reformate seldom contains more than 50 per cent of aromatics. The aromatics are recovered and purified by processes of adsorption (Arosorb or silica gel), extractive distillation (phenol), azeotropic distillation, or solvent extraction (Udex, diethylene glycol, or sulfur dioxide). 

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