Membrane Based Triethylene Glycol Separation and Recovery from ...

the two membrane module configurations-spiral wound (equipped with membranes:
NF270-2540) and NF90-2540) and tubular (equipped with membranes AFC 30) for
separation of EG.
Wastewater in petrochemical industry is currently treated by activated sludge process with
pretreatment of oil/water separation (Ravanchi et al., 2009). Tightening effluent
regulations and increasing need for reuse of treated water have generated interest in the
treatment of petrochemical wastewater with the advanced membrane bio-reactor (MBR)
process.
Pervaporation (PV) is a membrane process used to separate liquid mixtures. In the
dehydration application, water is removed from its mixtures with organic components by
selective permeation through a dense hydrophilic membrane. The most relevant application
of PV is the separation of liquid azeotropes and close boiling point solvent-water mixtures.
Nik et al. (2005) found that inorganic membranes and particular zeolite membranes are
usually used for the dehydration of organic solvent by pervaporation (PV). In this study on
the pervaporation dehydration of EG/water mixtures using commercial nanoporous NaA
zeolite membranes.
A non-porous membrane separates the liquid feed from a downstream compartment to
which vacuum is applied. On the feed side, water is preferentially absorbed on the
membrane. On the permeate side, the water molecules are desorbed and removed, due to
the application of vacuum. The sorption of water on the hydrophilic membrane creates a
water concentration gradient, resulting in a diffusive flux across the membrane. Owing to
the vacuum applied at the permeate side of the membrane, permeate is in the vapors state,
so a phase change occurs from liquid on the feed side to vapor on the permeate side.
Therefore, when looking at membranes to enhance performance, there is often a trade-off
between separation factor and total flux.
1.2 Objectives of the Study
This study aims to develop alternative treatment method for separation and recovery of
concentrated TEG from wastewater in Gas Separation Plants before they are discharged.
The specific objectives of this study are:
1) To investigate efficiency of nanofiltration, reverse osmosis and pervaporation
for TEG separation and recovery;
2) To develop pre-treatment processes to treat real wastewater generated from
dehydration unit in Gas Separation Plant Wastewater (GSPs).
1.3 Scope of the Study
To accomplish the above objectives, scope of study was set as follows:
1) The study was comprised of 3 phases, and their scopes are:
Phase I: High pressure membrane filtration study was conducted in benchscale
with various membrane types (NF/RO) and varying compound
concentration.
2