RECOVERY OF HYDROCARBON FROM VAPORIZED GAS IN OIL TANK

摘要

PURPOSE:To recover hydrocarbons, safely, continuously, in high efficiency, from voporized gas in an oil tank, by treating the gas with an absorber containing liquid hydrocarbons as absorbents, thereby reducing the concentration of the hydrocarbons in the gas, and then treating with an adsorber containing activated charcoal as adsorbent. CONSTITUTION:Vaporized gas (a) in an oil tank 1 is contacted countercurrently with a hydrocarbon-absorbent 3 in an absorber 4 to absorb the hydrocarbons (vapor) in the gas (a). Circulation gas (b) containing hydrocarbon vapor corresponding to the vapor pressure of the absorbent liquid 3 is recycled to the oil tank 1. The gas (d) which contains the hydrocarbons of the gas (a) in a sufficiently low concentration (about 1,000-3,000ppm) is introduced into an activated charcoal adsorber 2 to remove the hydrocarbons in high efficiency, and discharged to the outer atmosphere as exhaust gas (e). The used activated charcoal is regenerated with steam (f), and the desorbed hydrocarbons are cooled and condensed in a condenser 9. The liquefied hydrocarbons are separated from water in an oil-water separator 10, and recovered as a recovery oil (g).