BACKGROUND

Chemical processes often require multiple unit operations to produce a particular product stream. A particular unit operation may be a fluid-fluid contacting operation whereby two fluids are brought into intimate contact to promote mass transfer between the fluids, a reaction between components in the fluids, or both. An example of fluid-fluid contacting may be liquid-liquid contacting. Liquid-liquid contacting may be beneficial in some types of chemical reactions where one reactant is miscible in a first liquid but immiscible in a second liquid. An example of such a reaction may be where a first reactant is present in a polar solvent such as water and a second reactant is present in a non-polar solvent such as a hydrocarbon and the water and hydrocarbon are immiscible. Liquid-liquid contacting may have several applications such as liquid-liquid extraction whereby a species present in a first liquid is extracted into a second liquid by mass transfer across the liquid-liquid interface.

A particular challenge of fluid-fluid contacting may be ensuring adequate contact area between the two fluids such that the mass transfer or reactions may occur in an appreciable amount and in an economically viable manner. In general, fluid-fluid contacting operations may be performed with immiscible fluids, such as, for example, an aqueous liquid and a hydrocarbon liquid. Using two immiscible fluids may allow the fluids to be readily separated after the fluid-fluid contacting is completed. However, when a fluid-fluid contacting operation is performed with immiscible fluids, phase separation may occur before adequate contact between the fluids is achieved.

Several fluid-fluid contacting vessels and techniques have been developed to enhance the contact area between fluids in a fluid-fluid contacting process, including, but not limited to, fiber-bundle type contactors. A fiber-bundle type contactor may generally comprise one or more fiber bundles suspended within a shell and one or more inlets where the fluids may be introduced into the shell. The fiber bundle may promote contact between the fluids by allowing a first fluids to flow along individual fibers of the fiber bundles and a second fluids to flow between the individual fibers thereby increasing the effective contact area between the fluids. The two fluids may flow from an inlet section of the shell to an outlet section of the shell while maintaining intimate contact such that a reaction, mass transfer, or both may be maintained between the two fluids.

There may exist challenges with designing and operating fiber-bundle type contactors. Some fluid-fluid contactors may require large physical footprints to achieve adequate mass transfer between the fluids phases. Mass transfer between phases may be a function of surface area and therefore increasing surface area by making the fiber bundles larger or longer may also increase mass transfer between the fluids. Not only does producing a physically larger fiber bundle increase cost, there may be secondary considerations when the fiber bundle is larger. One consideration may be pressure drop across the fluid-fluid contactor which may increase with longer vessels and fiber bundles. Another consideration of larger fiber bundles may be phase separation whereby the relatively heavier, or denser, fluids may begin to migrate to the center of the fiber-bundle while the relatively lighter, or less dense, fluid may begin to migrate to the outside of the fiber-bundle. Similarly, in reaction applications, some reactions may require long residence times within a reactor to achieve adequate conversion which may in turn require larger fiber bundles.

SUMMARY

In an embodiment, apparatus may comprise: a body; a first partition in the body defining a first flow path between the body and the first partition; a first fiber bundle disposed within the first flow path; a second partition in the body defining a second flow path between the first partition and the second partition; a third partition in the body defining a third flow path between the second partition and the third partition; and a second fiber bundle disposed within the third flow path. In another embodiment, a method may comprise: introducing a fluid comprising a first immiscible phase and a second immiscible phase into a contacting vessel comprising multiple contact stages: flowing the fluid through a first fiber bundle disposed in the contacting vessel; separating at least a portion of the first immiscible phase from the second immiscible phase; and flowing the separated portion of the first immiscible phase through a second fiber bundle disposed in the contacting vessel. In another embodiment, A method may comprise: introducing a fluid comprising a hydrocarbon fluid and an aqueous fluid into a contacting vessel; flowing the fluid through a first fiber bundle disposed in the contacting vessel; separating a portion of the hydrocarbon from the fluid; combining the separated portion of the hydrocarbon with an additional amount of the aqueous solution to form a second fluid; and flowing the second fluid through a second fiber bundle disposed in the contacting vessel.

