6. Industrial implementation: permeation modules

6.1 Flat modules

The simplest implementation of membranes is the planar structure, offering the possibility of use in filter-press type systems. The basic pattern of a planar module consists of envelopes formed by membrane films welded together at the periphery. Spacers are placed inside the envelopes to delimit the hydraulic vein required for permeate flow. The shells are connected to a pierced central tube for permeate collection. A porous support is inserted between each envelope to act as a spacer for the feed flow (retentate side). The envelopes with their support/spacer are then stacked and placed in a calender. Special devices are fitted close to the center tube to ensure a good seal between the feed and permeate sides. Baffles are often used in the module to control flow...