Pleated, tapered, and spiral-wound cross-flow filter elements are described. The filter elements have pleated and tapered membrane leaves. The pleated and tapered membrane leaves maintain retentate fluid velocity in high permeate flux applications.

A membrane envelope stack for gas separation comprising membrane envelopes bonded together by means of an adhesive having a tensile E-modulus of at least 1600 N/mm.sup.2 and/or an elongation at break of 20% or less and/or a Tg of at least 50? C.

A gas separation module comprising gas separation elements, said elements comprising at least two membrane sheets and a permeate carrier sandwiched between the membrane sheets, wherein the permeate carrier comprises at least two macroporous layers and a gas-impermeable sheet located between the macroporous layers.

Disclosed is a spiral wound membrane element that provides two permeate streams through a permeate carrier sheet. The spiral wound membrane element is sealed such that the only communication with the permeate carrier is through a membrane sleeve. The first permeate stream flows spirally inward and the second permeate stream flows in the opposite direction, spirally outward. The permeate carrier sheet is sealed at two edges so that the permeate streams can only discharge from opposite, unsealed edges of the permeate carrier sheet. The first permeate stream may be collected in a central collection tube and the second permeate stream may be collected in a peripheral region of the membrane element.

A gas separation module comprising one or more gas separation elements, said elements comprising at least two membrane sheets and a permeate carrier sandwiched between the membrane sheets, wherein the contact area of the membrane sheets with the permeate carrier is less than 50%.

The present invention relates to a crossflow membrane module configured to separate a feed fluid into a permeate fluid and a residue fluid across one or more membrane sheet(s). The crossflow module comprises a second end offset from a first end along the first direction where an inlet is provided at the first end and an outlet is provided at the second end. The one or more membrane sheet(s) each have a first portion and a second portion. A conduit is adjacent to the first side of each membrane sheet and is configured to receive and output the permeate fluid separated from the feed fluid. The second portion of the membrane sheet has a greater permeance for a major component than the first portion such that the second part of the permeate fluid, which is generated by separation across the second portion of the membrane sheet, has a higher concentration of the major component than the first part of the permeate fluid, which is generated by separation across the first portion. The second portion is spaced apart from the first side of the membrane sheet along the second direction thereby causing the second part of the permeate gas to flow towards the first side of the membrane sheet such that the second part of the permeate gas mixes with the first part of the permeate gas thereby reducing the concentration of the minor component in the first part of the permeate gas.

A permeate carrier to be described in detail below has side edges, alternatively called borders, that are thinner than a central part of the permeate carrier. Adhesive is applied to the side edges to form a seal when a membrane leaf is formed around the permeate carrier. After the membrane leaf is wound around a central tube, the side edges extend in a spiral around the central tube. The transition between the side edges and the central part of the permeate carrier helps prevent adhesive from flowing into the central part of the permeate carrier. The reduced thickness of the side edges also reduces an increase in diameter at the ends of an element that might otherwise be caused by the adhesive.

The present invention provides a filter element (500) having a radial permeate discharge path (550). The filter element generally includes a closed membrane structure (510) wrapped about a core (530) in reciprocating clockwise and counterclockwise directions, forming semicircular folds of membrane about the core. The semicircular folds of membrane have opposingly situated apical ends (560) separated by a gap. The interior of the closed membrane structure (510) defines a feed channel and the exterior of the closed membrane structure defines at least one permeate channel (522). A radial permeate discharge path (550) extends through the gap between the apical ends of the semicircular folds of membrane. Systems containing, and methods of using, filter elements including radial permeate discharge paths are also provided.

A spiral separation membrane element includes a water collection tube; a separation membrane wound around the water collection tube, having a feed-side surface and a permeate-side surface, and including a band-shaped region on at least one end of the feed-side surface in an axial direction of the water collection tube; and a channel material fused to the band-shaped region.

Membrane elements that use multiple membrane leaves may have a limited total active membrane area due to an increased diameter at the ends of the element. Membrane leaves may comprise a permeate carrier positioned between one or more membrane sheets. Adhesive may be used to seal one or more edges of the membrane leaf. The membrane sheets, permeate carrier and the adhesive contribute to the thickness of the edges of the membrane leaf and the diameter at the ends of the element. A reduced thickness of the edges of the permeate carrier may reduce the diameter at the ends of an element. Another permeate carrier sheet may also be used that is distanced from at least one edge of the membrane sheet so the permeate carrier sheet does not contribute towards the increased diameter at the ends of the element.