Membrane and Desalination Technologies - TCE Moodle Website

300 J. Paul Chen et al.
6.2.3. Tubular Module
Fig. 7.10. A spiral-wound module.
In this type of module, a number of membranes of tubular shape are encased in a container.
A schematic diagram is given in Fig. 7.12. The feed solution always flows through the centre
of the tubes while the permeate flows through the porous supporting tube into the module
housing. Ceramic membranes are mostly assembled in such tubular module configurations.
The main features of the tubular module are:
l Convenience in membrane replacement and easy cleaning of surface contamination
l High-energy consumption per unit amount of liquid treated
l High feed flow rate help reduce the membrane contamination
l Low packing density of the module
l Simple pre-treatment of feed liquid
6.2.4. Hollow-Fibre Module
Hollow-fibre module consists of a large number of fibres assembled together in a module,
as shown in Fig. 7.13. The free ends of the fibres are often potted with agents such as epoxy
resins, polyurethanes or silicon rubber. The membranes are self-supporting for this module.
There are two basic types of arrangement for this module:
1. Inside-out, as shown in Fig. 7.14a, where the feed solution passes through the bore of the fibre and
the permeate is collected on the outside of the fibre
2. Outside-in, as shown in Fig. 7.14b, where the feed solution enters the module on the shell side of
the fibres and the permeate passes into the fibre bore