Flotation apparatus for clarifying produced water

摘要

A dissolved gas flotation apparatus and process for removing oils and other contaminants from produced water generated in the production of crude petroleum and natural gas. The invention is particularly designed for offshore applications, where space is limited and natural gas is readily available. The invention includes a vessel for receiving and maintaining a liquid level therein and a circulating pump for introducing tiny flotation gas bubbles into the vessel. Natural gas is used as a blanket gas for the vessel and as a source of gas fed into the pump, wherein the gas is mixed with the pumped liquid. The liquid/gas mixture is transferred into the vessel, wherein the gas releases from the liquid, thereby forming tiny, finely dispersed gas bubbles. The tiny gas bubbles rise vertically through the vessel and attach themselves to the oil and other contaminants suspended in the liquid and buoyantly transport the oil and other contaminants to the top of the vessel, where the gas is released and either recycled back to the recirculating pump or transferred out of the vessel for further processing, and the oil and other contaminants are collected in a reservoir for recovery. The clarified water is removed from the vessel through a liquid outlet line located near the bottom of the vessel.