Dual Affinity Membrane Hydrocyclone for Simultaneous Water Purification and Oil Recovery from Produced Water
A large amount of contaminated waste water is generated from wellheads at offshore platforms during oil and gas productions. These heavily oil-contaminated waters cannot be discharged directly back into the environment and are currently purified by a number of expensive separation techniques. Effective separation of waste water into water and oil phases has tremendous potential to both decrease the environmental footprint of the oil industry and recover large amounts of oil that are now disposed of in addition to the existing partially cleaned waste-water stream.
Description of Technology
Michigan State University’s invention is a significant improvement to an existing technology for separating oil and water generated from wellheads at offshore oil platforms. Existing centrifugal technologies have a filter to separate partially de-emulsified water from an oil-rich residue. The MSU technology uses two coaxial cylindrical membranes in which water has a strong circumferential (i.e., centrifugal) flow. There is a hydrophilic ceramic membrane at an outer surface through which water selectively passes and a hydrophobic polymer membrane on an inner surface through which oil selectively flows. The centrifugal flow aids this separation process, where the denser water migrates to the outer membrane and the less dense oil to the inner membrane. Additionally, at the outer membrane, the following parameters can be varied: water pressure, membrane pore size, membrane chemistry, and tube configuration.
- Efficiency gains: The invention combines centrifugal technologies with the use of coaxial membranes: one hydrophilic and the other hydrophobic. This promises to be a significant improvement in the efficiency of the separation of oil from water in waste streams from oil platforms, and a resulting reduction in cost.
- Net cost reductions: The invention provides net reductions in the cost of the waste-water treatment due to efficiency gains and, in particular, the net economic value of the separated oil.
The technology has applications for waste water treatment from oil platforms.
Volodymyr Tarabara, Wenqian Shan
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Michigan State University