Process and apparatus for recovering hydrocarbons from air-hydrocarbon vapor mixtures

摘要

A process and apparatus for recovering hydrocarbons from an air-hydrocarbon vapor mixture such as the mixture of air and vaporized light hydrocarbon compounds expelled as a result of loading gasoline or the like into storage tanks, tank cars and tank trucks. The air-hydrocarbon vapor mixture is caused to flow through a bed of solid adsorbent whereby the hydrocarbons ar removed from the mixture and a residue gas stream comprised of substantially hydrocarbon-free air is produced. The substantialy hydrocarbon-free air is vented to the atmosphere and while the first bed is removing hydrocarbons from the air-hydrocarbon vapor mixture, a second bed of solid adsorbent having hydrocarbons adsorbed thereon is simultaneously regenerated by evacuating the bed with vacuum pumping and the air-hydrocarbon vapor mixture produced in the regeneration of the bed is contacted with a liquid absorbent whereby a major portion of the hydrocarbons are absorbed therefrom and recovered. The beds of solid adsorbent are cooled, at least while the air-hydrocarbon vapor mixture is flowing therethrough and hydrocarbons are being adsorbed on the bed, to prevent the beds from overheating due to side exothermic reactions of hydrocarbons and/or impurities contained in the air-hydrocarbon vapor mixture with air and/or the solid adsorbent. Apparatus for carrying out the process of the present invention is also provided.