The most important are the activated carbons. They can be produced from a variety of sources such as wood, coconut or other types of nutshells, or petroleum feedstocks. The activated carbon has great efficiency and the largest holding capacity for the greatest area and lowest density of all the common adsorbents. Only one of the three processes is described here. 2.2 Purpose Because of the high cost of maintenance of air purification systems in applications of high concentrations of organic vapours, scientists have been forced into research and design of systems for solvent recovery.
Some situations utilize throw away adsorbent beds.
This situation occurs when the adsorbate is of no appreciable value. In solvent recovery operations, thick beds are used with regular regeneration. In all such situations, effective and easy reversibility of adsorption is an economic necessity. In order to provide the required degree of recovery and control, a dual, if not triple, parallel bed arrangement is used. The mixture is absorbed from various ducts or inlets, which is a direct connection to point emission source.