Hollow fiber membranes
AssigneeUnion Carbide Industrial Gases Technology Corporation
InventorsBenjamin Bikson, James T. Macheras, Joyce K. Nelson
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Abstract
A process for producing highly asymmetric hollow fibers useful as permselective gas separation membranes and for producing composite membranes thereof by extruding the spinning dope through a tube-in-orifice spinneret into a gas-filled chamber maintained at reduced pressure and then conveying the extruded hollow fiber through a liquid bath to solidify the extrudate.
Claims51
A process for separating a first gaseous component from a mixture thereof with at least one other gaseous component which comprises:
- 1) contacting said mixture with a highly asymmetric gas separation hollow fiber membrane prepared by the process that comprises:
- a) forming a mixture of fiber-forming polymer and at least one solvent, said polymer being capable of affecting separation of the first gaseous component from said at least one other gaseous component;
- b) extruding the polymer-solvent mixture in the form of a hollow fiber into a gaseous atmosphere maintained at a subatmospheric pressure;
- c) conveying into and solidifying the polymer-solvent mixture in a liquid medium;
- d) washing the solidified polymer;
- and
- e) recovering a solidified highly asymmetric hollow fiber membrane;
- and
- 2) recovering the component of said mixture passing selectively through the solidified highly asymmetric hollow fiber membrane;
- and
- 3) separately recovering the component of said mixture not passing selectively through the solidified highly asymmetric hollow fiber membrane.
A process for separating a first gaseous component form a mixture hereof with at least one other gaseous component which comprises;
- 1) contacting said mixture with a composite gas separation membrane comprising a thin layer of gas separation material that substantially determines the gas separation characteristics of said composite gas separation membrane, said thin layer deposited on the surface of a highly asymmetric porous hollow fiber substrate such that said thin layer is less than about 400 .ANG. thick, said highly asymmetric porous hollow fiber substrate produced by:
- a) extruding a solution of a fiber-forming polymer through a spinneret into a vacuum chamber containing a gaseous medium maintained at subatmospheric pressure,
- b) thereafter passing the solution of a fiber-forming polymer extruded through the spinnet into a liquid bath to solidify the hollow fiber,
- c) washing the solidified fiber, and
- d) recovering a solid highly asymmetric hollow fiber;
- 2) recovering the component of said mixture passing selectively through the thin layer of gas separation material;
- and
- 3) separately receiving the component of said mixture not passing selectively through the thin layer of gas separation material.
A highly asymmetric gas separation hollow fiber membrane prepared by the process comprising:
- a) forming a mixture of fiber-forming polymer and at least one solvent;
- b) extruding the polymer-solvent mixture in the form of a hollow fiber into a gaseous atmosphere maintained at a subatmospheric pressure;
- c) conveying into and solidifying the extruded polymer-solvent mixture in a liquid medium;
- d) washing the solidified fiber;
- and
- e) recovering the solidified highly asymmetric hollow fiber membrane.
A composite gas separation membrane comprising a thin layer of gas separation material that substantially determines the gas separation characteristics of said composite gas separation membrane, said gas separation material deposited on the surface layer of a highly asymmetric porous hollow fiber substrate wherein the surface layer region of said asymmetric porous hollow fiber substrate is less than about 400 .ANG. thick, said highly asymmetric porous hollow fiber substrate produced by extruding a solution of a fiber-forming polymer through a spinneret into a vacuum chamber containing a gaseous medium maintained at subatmospheric pressure, thereafter passing the solution of a fiber-forming polymer extruded in the spinneret into a liquid bath to solidify hollow fiber, washing the solidified fiber and recovering a highly asymmetric hollow fiber substrate.
A process for forming highly asymmetric hollow fiber for gas separations comprising extruding a solution of a fiber-forming polymer through a spinneret into a vacuum chamber containing a gaseous medium maintained at subatmospheric pressure, and thereafter passing the extruded solution of a fiber forming polymer into a liquid bath to solidify the hollow fiber, washing the solidified fiber and recovering a highly asymmetric hollow fiber.
Dependencies are inferred from the claim text.