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An improved process and apparatus are provided for recovering hydrocarbons from an intermittent or continuous inlet air-hydrocarbon vapor mixture. The air-hydrocarbon vapor mixture is caused to flow through a bed of solid adsorbent whereby hydrocarbons are removed therefrom and a residue gas stream

An improved process and apparatus are provided for recovering hydrocarbons from an intermittent or continuous inlet air-hydrocarbon vapor mixture. The air-hydrocarbon vapor mixture is caused to flow through a bed of solid adsorbent whereby hydrocarbons are removed therefrom and a residue gas stream of substantially hydrocarbon-free air is produced. The substantially hydrocarbon-free air is vented into the atmosphere and a second bed of solid adsorbent having hydrocarbons previously adsorbed thereon is regenerated by evacuation. As long as the concentration of hydrocarbons contained in the vented air is below a predetermined concentration, the inlet air-hydrocarbon vapor mixture is caused to continue to flow through the first bed of adsorbent. After the second bed of adsorbent is regenerated, the pumping and evacuation of the second bed is shut down and not restarted so long as the monitored concentration of hydrocarbons is below the predetermined concentration.

대표청구항 ▼

[ What is claimed is:] [1.] An improved process for recovering hydrocarbons from an intermittent or continuous inlet air-hydrocarbon vapor mixture comprising the steps of:(a) flowing said air-hydrocarbon vapor mixture through a first bed of adsorbent whereby said hydrocarbons in said mixture are ads

[ What is claimed is:] [1.] An improved process for recovering hydrocarbons from an intermittent or continuous inlet air-hydrocarbon vapor mixture comprising the steps of:(a) flowing said air-hydrocarbon vapor mixture through a first bed of adsorbent whereby said hydrocarbons in said mixture are adsorbed on said bed and a residue gas stream comprised of substantially hydrocarbon-free air is produced;(b) venting said substantially hydrocarbon-free air to the atmosphere;(c) monitoring the concentration of hydrocarbons contained in said vented substantially hydrocarbon-free air;(d) continuing to flow said inlet air-hydrocarbon vapor mixture through said first bed so long as said concentration of hydrocarbons monitored in accordance with step (c) is below a predetermined concentration;(e) evacuating a second bed of adsorbent having hydrocarbons adsorbed thereon by subjecting said bed to pumping with a vacuum pump whereby hydrocarbons are desorbed from said bed and a hydrocarbon rich air-hydrocarbon vapor mixture is produced;(f) recovering a major portion of said hydrocarbons from said hydrocarbon rich air-hydrocarbon vapor mixture produced in accordance with step (e) and combining the remaining air-hydrocarbon vapor mixture with said inlet air-hydrocarbon vapor mixture of step (a);(g) terminating said pumping with said vacuum pump and said evacuation of said second bed in accordance with step (e) after a major portion of said hydrocarbons are desorbed therefrom, and continuing said pumping termination for so long as said concentration of hydrocarbons monitored in accordance with step (c) is below said predetermined concentration;(h) changing the flow pattern of said inlet air-hydrocarbon vapor mixture whereby it flows through the bed of adsorbent which has been evacuated in accordance with step (e) and changing the bed of adsorbent to be evacuated to the bed of adsorbent which has been adsorbing hydrocarbons in accordance with step (a) when said concentration of hydrocarbons monitored in accordance with step (c) is equal to or above said predetermined concentration; and(i) repeating steps (a) through (h).