Activated carbon adsorption
Filters based on activated carbon have been used historically to deodorize compressed air and are particularly effective for the removal of oil vapour contaminants. Activated carbon is not effective for oxides of carbon, methane, ethylene, ammonia and sulphur compounds for which chemical or catalytic methods can be used.
Activated carbon is excellent for adsorbing oil vapour and is suitable for purification of compressed air. The activated carbon must be in a finely granulated form to present as much surface area as possible for adsorption. This is done in a granulated tube, which has a large surface area and a deep bed to increase the contact time.
Activated carbon has a selective preference for oil vapour over water vapour, which is of vital importance for even instrument quality compressed air has more water vapour than oil vapour. The efficiency of activated carbon filters should be such that there is no trace of hydrocarbons or odour in the delivered air.