Abstract: The present invention provides a method for mixing a liquefied hydrocarbon gas extracting a flow of hydrocarbon containing water. The method involves; a) introducing the liquefied hydrocarbon gas extracting into the water to provide water having entrained droplets of the extract and/or the hydrocarbon; b) subjecting the water to a first pressure drop to fragment the entrained droplets c) optionally, mixing the water and the liquefied hydrocarbon gas to promote distribution of the liquefied hydrocarbon gas in the water; and d) subsequently subjecting the water having entrained droplets to a second pressure drop, to coalesce the entrained droplets. The invention also provides a method for extracting contaminants involving the mixing method and apparatus suitable for carrying out the methods of the invention.

Abstract: A new process for simultaneous extraction of dispersed and dissolved hydrocarbon contaminants from water. The process is based on the principle of injecting natural hydrocarbon gas to the water feed stream under pressure and temperature conditions which permit the gas to act as a solvent for dissolved and dispersed hydrocarbon contaminants. The dispersed particles "swell" and have a reduced density which markedly improves the efficiency of the downstream separation by liquid--liquid-hydrocyclones.