Development of adsorption buffer and pressure swing adsorption (PSA) unit for gasoline vapor recovery

The effect of a double layered adsorber on the recovery of gasoline from gas emitted from a gasoline storage tank was investigated. The adsorber consists of two different adsorbents: silica gel and activated carbon. A pilot system consisting of an adsorptive buffer for the collection of contaminated air sporadically emitted and a PSA system was installed and operated. Gas from a gasoline tank was fed to the adsorption buffer for a period of time, and subsequently the enriched hydrocarbon stream obtained during the regeneration of the adsorptive buffer was treated by the PSA system. Regeneration of the adsorbent was done by flowing clean air under vacuum. Approximately 21-48 liters of gasoline per hour was recovered with the pilot-scale PSA unit filled with 435 kg of adsorbent in total. The gas emitted from the system contains light hydrocarbon less than 100 ppmv.