Pressurized, sparged flotation column

摘要

A method for removing residual oil from oily water under pressure is provided. The method comprises flowing a liquid stream of an oily water downward through a vertically extended zone to remove the residual oil. A gas is injected into the lower end of the zone and at a rate sufficient to generate bubbles of a predetermined volume in the liquid stream. A sufficient pressure is maintained in the zone to control the rate of expansion of the bubbles to a volume compatible with oil droplets in the liquid stream during upward migration of the bubbles and the oil droplets. The rate of flow of the liquid stream from the lower end of the zone and the rate of flow of the gas from the upper end of the zone are regulated to collect residual oil from a quiescent volume within the upper portion of the zone.