- SideStroem and Singapore Institute of Technology featured in AsianScientist - April 29, 2023
- SideStroem joins world class accelerator program - November 12, 2022
- SideStroem Water Technologies and the Singapore Institute of Technology (SIT) collaborate to develop nanofiltration-type forward osmosis (NF-FO) membranes - September 14, 2022
Tubular modules made from tubular forward osmosis membranes
Tubular module summary
|Packing density||Up to 500 m2/m3|
|Advantage||ease of modularization and ease operation when waste-streams contain high amounts of fouling agents and/or solutions entering the module have high viscosity|
|Disadvantage||tube wall thickness might limit the water flux performance of tubular FO membrane modules to a level where the modules are not economically viable|
Membrane modules based on tubular membranes are well-known in the water treatment industry for ultra-filtration applications with high fouling / high viscosity waste water streams. Briefly, porous tubes with inner diameters ranging from 5mm to 15mm are coated with micro-porous layers of PVDF or PES on either the inside or outside walls. Depending on the orientation of the micro-porous layer, tubular modules – consisting of individual tubular membranes fitted into a cylindrical housing – are either operated in outside-in (waste water stream flowing outside individual tubes) or inside-out (waste water stream flowing inside individual tubes) configurations.
From a forward osmosis module point of view, tubular modules should be seen as an alternative to plate and frame modules in applications with high fouling / high viscosity waste water streams. Compared to plate and frame modules, tubular modules offer two main advantages:
- Up to 4-5 times higher packing densities (refer to the table below) significantly reduce the overall footprint of tubular forward osmosis modules
- Tubular modules are inherently easier to produce since they only require sealing at either end of the module
However, there are also drawbacks to using tubular forward osmosis membranes. First of all such membranes are currently not commercially available and most R&D efforts are directed towards flat sheet and hollow fibre FO membranes. Secondly, the overall thickness of the porous tube wall – including the PVDF or PES micro-porous layer – might render the tubular configuration unfit for forward osmosis processes due to severe build-up of internal concentration polarization.
|Tube wall thickness||0,4mm|
|Tube inner diameter||10mm|
|Tube inner area||0,031m2|
|Inner diameter of module||220mm|
|Number of tubes in module||319**|
|Internal volume of module||0,038m3|
|Active area per module||10m2|
** See engineeringtoolbox.com for an online calculation tool of how many small circles fit into a large circle
Please follow the links below for descriptions of other design variants of forward osmosis modules
- Plate and frame forward osmosis membrane modules
- Spiral wound forward osmosis membrane modules
- Hollow fiber forward osmosis membrane module
3 thoughts on “Tubular forward osmosis membrane modules”
Can I buy this FO membrane item?
Hi I am also interested in these membranes and couldn’t find any contact detail. dear Admin can you please send me some information, mainly contact detail, of the producer. I do not need large quantity at this stage and even lab scale production is fine.
Apologies for the late reply and thanks for reaching out. I suggest you contact Head of R&D at Aquaporin Asia, Dr. Guofei Sun, at email@example.com for more information.