ADSORPTION COLUMN (EN: adsorption column, adsorption tower; DE: Adsorptionssaule, Adsorber; FR: colonne d'adsorption; ES: columna de adsorcion; RU: адсорбционная колонна) is the apparatus for the adsorption of one or several components from the mixture of the gases or from the solution by the solid substance, which is called the adsorbent.
It is used during the extraction from the gases and liquids of the various substances, which are contained there in the low concentrations, of the volatile solvents from their mixtures with the air or some gas, in the processes of the drying and cleaning of the natural gases, etc. The solid porous substances with the large specific surface are used as the adsorbent, namely the active carbons, zeolites, silica gel, ion exchange resins (ionites), and others. The concentrating of the extracted components is performed on the surface or in the pores of the adsorbent (Figure).
They distinguish the adsorption columns with the fixed bed (layer) of the adsorbent, in which the adsorption is performed periodically (is resumed after the desorption), and with the moving or fluidized (bubbling) bed (layer), in which the adsorption proceeds continuously. The periodically acting adsorbent is located in the adsorption columns on the horizontal grid. After the saturation of the adsorbent, which is determined by the start of the skip through of the adsorbed substance (gas or liquid), the desorption is performed, and then the process is restarted. If there are several adsorption columns constituting the installations, then the work may be organized in the continuous loop; then the columns are working alternately one at a time. In the adsorption columns with the moving bed (layer), the adsorber continuously moves downward according to the action of the force of the gravity, while the gas or the liquid rises from the opposite direction, then the adsorption proceeds in the top part, and the desorption (according to the action of the heating) proceeds in the bottom part.
The products of the desorption are driven out from the column. In order to obtain the "fluidized (bubbling)" bed (layer) of the adsorbent in the adsorption columns, the gas is delivered from the bottom. While passing through the grating, on which the bed (layer) of the finely crushed adsorbent is laying, the gas transforms it into the fluidized state of the substance. The adsorbent is continuously delivered from the top, and after the exhaustion is removed for the desorption.
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