1.0 Introduction
Adsorption is a process in which a substance becomes attached to the surface of a solid or liquid. The substances adsorbed at a solid or liquid. The substances adsorbed at a solid surface may be gases, liquids or other solids (from solution). The amount of material adsorbed by a given mass of adsorbent when the solid is porous of finely divided is large. This confirms theory that adsorption is a surface phenomena, since the surface area exposed is much greater when the particles are smaller.
The adsorption operations exploit the ability of certain solids preferentially to concentrate specific substances from solution into their surface. In this manner, the components of either gaseous or solid solutions can be separated from each order.
In the field of gaseous separation, adsorption is used to dehumidify air and other gases, to remove objectionable odours and impurities from industrial gases such as carbon dioxide to recover valuable solvents vapours from dilute mixture with air and other gases, and to fractionate mixtures of hydrocarbon gases containing such substances as methane, ethylene, ethane, propylene and propane.
Adsorption from liquid phase is used to remove moisture dissolved in gasoline, decolourisation of petroleum products and aqueous sugar solutions, removal of objectionable teste and odour from water, and the fractionation of mixtures of aromatic and paraffinic hydrocarbons.
1.1 Objectives of Study
Our main objective in this project is to refurbish fixed bed adsorption column. The scale of operation ranges from the use of a few grams of adsorbent in the laboratory to industrial plants with an adsorbent inventory.
These operations are all similar in that the mixture to be separated is brought into contact with another insoluble phase, the adsorbent solid, and the unequal distribution of the original constituents between the adsorbed phase on the solid surface and the bulk of the fluid then permits a separation to be made. All the techniques previously found valuable in the contact of insoluble fluids are useful in adsorption. Thus, we have batch wise single — stage and continuous multistage separations and separations analogous to counter current absorption and stripping in the field of gas — liquid contact and to rectification and extraction with the use of reflux. In addition, the rigidity and immobility of a bed of solid adsorbent particles make possible useful application of semiconscious methods which are not at all practicable when two fluids are contacted.
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