The Dow Chemical Company

Damoder Reddy

Theodore L Parker

John A Jensvold

Wendy S Jacks

Srikanth Ranga Chary

Tag Y Moon

Keith R Denslow

Hans R Keller

Charles E Reineke, Deceased

The invention is a process for obtaining membranes having improved selectivity and recovery using a combination of heat treating and UV irradiation.

Membranes having improved selectivity and recovery, and process for

The present invention relates to a spiral-wound membrane module having a semi-permeable membrane which has a central high pressure premeatae region flanked on opposite sides by two lower pressure edge portions. The edge portions facilitate the dispersion of and the collection of the feed fluid being treated and assist in obtaining a more uniform flow of the feed fluid through the high pressure region of the membrane. In one embodiment, the module has entrance and exit flow means for a counter-current flow of a sweep fluid through the permeate. Preferably, the high pressure permeate region is a high density porous spacer flanked on two sides with low density porous spacers. In one embodiment, the higher pressure permeate region and flanking low pressure drop permeate regions are obtained by specifically positioned lines of adhesive or glue spots (or lines) having a specific size and spacing. Generally the spots (or lines) are positioned in a generally axial configuration to the central pipe. Generally, the glue spots or lines are positioned in the permeate passageway in a pattern to obtain controlled flow of the countercurrent, cocurrent, or crosscurrent sweep fluid.

Spiral-wound membrane separation device with feed and permeate/sweep

The present invention relates to an improved design for a spiral wound membrane separation device. The improved module has one feed pipe separated into compartments which are connected axially to a porous spacer surrounded by a membrane envelope. A separate permeate pipe is immediately adjacent and generally in a parallel configuration to the fluid feed pipe and is in fluid communication with a different porous spacer sheet. When the porous feed membrane and pipe and spacer and permeate pipe are combined using appropriate complementary shaped spaced filling means, a spiral wound membrane separation device is obtained having two centrally located pipes. In one aspect, the membrane separation module further includes means for the addition of a countercurrent or cocurrent sweep fluid (gas) the permeate.

Counter current dual-flow spiral wound dual-pipe membrane separation

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San Ramon, CA, United States of America

Damoder Reddy