Method of removing dissolved oil from produced water

摘要

This invention involves a process and apparatus for removing dissolved and undissolved oil and chemical additives from waste and/or produced water streams. The process involves contacting a selected gas with the produced water stream, the selected gas utilizing hydrogen bonding and dipole interactions with the contaminants to remove them from the water. The rise rate of the selected gas is accelerated by mixing natural gas with the selected attractive gas. The selected gas and natural gas are recovered by the application of vacuum to the waste stream after treatment. The selected gas is separated from the natural gas by compressing and cooling the combined gas stream, venting the majority of the natural gas stream while the selected gas is liquified, then expanding the selected gas before returning it to the flotation vessel. Means are also provided for mixing the selected and natural gases with the contaminated water stream at line pressure so that mixing is intimate and flotation is accelerated.