Separation of oil-containing water into oil and water is a commonly performed task in most oil production and processing facilities, and there are numerous methods known in the art. For example, oil and various other suspended solids can be passed through an API (American Petroleum Institute) separator using the difference in specific gravity of the oil, water, and suspended solids in a process that is based on the principles of Stokes law. Such separators are conceptually simple and relatively easy to operate, however, often require a secondary treatment device as the separation efficiency is less than ideal. Secondary separation devices include corrugated plates interceptor (CPI) separators in which a series of tilted plates in the flow path is used as an enlarged surface area to enhance coalescence of the oil phase and settlement of the suspended solids. Once more, such separators are relatively simple, however, tend to require at least some maintenance and clean-up.
Where the amount of oil and suspended solids are relatively low, induced gas flotation (IGF) and dissolved gas flotation (DGF) devices can be employed to enhance flotation and separation of the oil and suspended solids. Such devices are often effective, however, require in at least some cases multiple moving parts. Moreover, IGF and DGF devices often require maintenance and are typically less desirable for offshore operation.
Consequently, although many configurations and methods for oil water separation are known in the art, all or almost all of them suffer from various disadvantages. Most significantly, it would be desirable to have a device that could operate as a single device with minimal or no moving parts, and that also requires little or no operator attention. Thus, there is still a need to provide improved methods and devices for oil water separation.