NAMS 2002 Workshop - ICOM 2008

Gas Separation III – 1 – Keynote
Wednesday July 16, 9:30 AM-10:15 AM, Kaua’i
Membrane Engineering Progresses and Potentialities in Gas Separations
E. Drioli (Speaker), Research Institute on Membrane Technology, ITM-CNR, Italy -
e.drioli@itm.cnr.it
Membrane processes for gaseous mixture separations are today a well
consolidated technique competitive in various cases with the traditional
operations [1]. Separation of air components, natural gas dehumidification,
separation and recovery of CO2 from biogas and natural gas, and of H2 from
refinery industrial gases are some examples in which membrane technology is
applied already at industrial level. The separation of air components or oxygen
enrichment has advanced substantially during the past 10 years. The oxygen-
enriched air produced by membranes has been used in various fields, including
chemical and related industries, the medical field, food packaging, etc. The
possibility of utilizing membrane technology in solving problems such as the
greenhouse effect related to CO2 production has also been suggested.
Membranes able to remove CO2from air, having a high CO2/N2 selectivity, might
be used at any large-scale industrial CO2source as power station in
petrochemical plants. The CO2separated might be converted by reacting it with
H2 in methanol, starting a C1 chemistry cycle. A membrane reactor might be
ideally used to carry out hydrogenation reactions for chemical production using
CO2 recovered from exhaust gases by membrane separation. The separation
and recovery of organic solvents from gas streams is also rapidly growing at the
industrial level. Polymeric rubbery membranes that selectively permeate organic
compounds (VOC) from air or nitrogen have been used. Such systems typically
achieve greater than 99% removal of VOC from the feed gas and reduce the
VOC content of the stream to 100 ppm or less. The significant positive results
reached in gas separation membrane systems are however still far away to
realize the potentialities of this technology. Problems related to the pretreatments
of the streams, to the membranes life time, to their selectivity and permeability
still exist slowing down the growth of large scale industrial applications. New
polymeric inorganic and hybrid materials are under investigation in different
laboratories around the world. The possibility to realize also new mass transport
mechanisms as the ones characterizing the perovskites membranes is becoming
of interest. The case of O2 and H2 transport in these membranes might be
extended to other species by realizing new specific materials. Molecular
dynamics studies, fast growing in this area, might contribute to the design of
these new inorganic materials or to the appropriate functionalization of existing
polymeric membranes. Amorphous perfluoropolymers might be utilized for
casting asymmetric composite membranes [2] with interesting selectivity and
permeabilities for various low molecular species. Their cost is however a