Recovery of hydrocarbon components from a hydrocarbon-carrier gas mixture

A process for recovering hydrocarbons from an inlet stream of a hydrocarbon-carrier gas mixture comprising the steps of:

• passing an amount of the inlet stream into contact with a solid adsorbent material so that the hydrocarbon is selectively adsorbed and a first venting stream of substantially hydrocarbon free air is simultaneously exhausted, while the adsorbent material is maintained at substantially the pressure of the inlet stream;
• passing a flushing stream of rich hydrocarbon-carrier gas into contact with the solid adsorbent material;
• desorbing the hydrocarbon from the solid adsorbent material to produce a rich hydrocarbon-carrier gas product stream;
• passing the rich hydrocarbon-carrier gas product stream into contact with a further amount of the solid adsorbent material so that the hydrocarbon is selectively adsorbed and a second venting stream of substantially hydrocarbon free carrier gas is simultaneously exhausted, while the adsorbent material is maintained at substantially the pressure of the inlet stream;
• passing another flushing stream of rich hydrocarbon-carrier gas into contact with the solid adsorbent material;
• and
• desorbing the hydrocarbon from the further amount of solid adsorbent material to produce a richer hydrocarbon-air product stream.

A process for recovering hydrocarbon from a hydrocarbon-air mixture, comprising the steps of:

• (a) passing the hydrocarbon-air mixture through an adsorber having a solid adsorbent bed capable of selectively adsorbing hydrocarbon components from the mixture to leave substantially hydrocarbon free air;
• (b) simultaneously venting the substantially hydrocarbon free air to the atmosphere, while maintaining the adsorbent bed at substantially the pressure of the hydrocarbon-air mixture;
• (c) flushing the solid adsorbent bed with a flushing stream of gas which will be adsorbed to a greater degree than the carrier gas so that the carrier gas is displaced from the adsorbent bed and venting a displaced carrier gas therefrom;
• (d) submitting the hydrocarbon laden solid adsorbent bed to a vacuum with a first liquid ring vacuum pump to desorb the hydrocarbon components therefrom and produce a rich hydrocarbon-air vapor mixture containing a liquid from the first liquid ring vacuum pump and recovered hydrocarbon from the mixture;
• (e) separating the hydrocarbon and the liquid injected in the vapor by the liquid ring vacuum pump to produce a first product stream comprising a gas mixture rich in the adsorbed hydrocarbon components;
• (f) passing the first product stream to another adsorber having a solid adsorbent bed capable of selectively adsorbing the hydrocarbon components from the first product stream to leave substantially hydrocarbon free air;
• (g) simultaneously venting the substantially hydrocarbon free air to the atmosphere, while maintaining the adsorbent bed at substantially the pressure of the first product stream;
• (h) flushing the other solid adsorbent bed with a flushing stream of gas which will be adsorbed to a greater degree than the carrier gas so that the carrier gas is displaced from the adsorbent bed and venting a further amount of the displaced carrier gas;
• (i) submitting the other hydrocarbon laden solid adsorbent bed to a vacuum with a liquid ring vacuum pump to desorb the hydrocarbon components therefrom and produce a rich hydrocarbon-air vapor mixture containing a liquid from the second liquid ring vacuum pump and recovered hydrocarbon from the first product stream;
• and
• (j) separating the hydrocarbon and the liquid injected in the vapor by the second liquid ring vacuum pump to produce a second product stream comprising a gas mixture richer in the adsorbed hydrocarbon components.