NAMS 2002 Workshop - ICOM 2008

NAMS Alan S. Michaels Award – 2
Tuesday July 15, 9:30 AM-9:55 AM, Kaua’i
Enhancing Natural Gas Purification with Advanced Polymer/Molecular
Sieve Composites
S. Miller (Speaker), Chevron Energy Technology Company, Richmond, CA, USA
D. Vu, Chevron Energy Technology Company, Richmond, CA, USA, devu@chevron.com
Membranes have been of continuing interest to the petroleum and chemical
industries for gas separations. While glassy, polymeric membranes have
provided efficient performance to date, significant improvements over current
membrane technology will likely require novel materials. This paper will review
the development and status of a new technology based on composite
membranes, termed mixed matrix membranes, of polymer matrices in which
molecular sieves are dispersed to give enhanced separation of natural gas from
its impurities compared to membranes of the polymer alone.
The technology is particularly of interest to the separation of natural gas from its
impurities, such as CO2 and H2S.
In laboratory testing, the composite membranes, composed of molecular sieves
in commercial membrane polymer matrices, showed significant improvement in
both selectivity and flux compared to membranes of the polymers alone for the
separation of CO2 from natural gas. Enhancements were obtained using both
carbon molecular sieves and small pore zeolites.
While membranes have been of interest due to their compactness, light weight,
and ease of operation, there has not been widespread application due to low
selectivity and flux, and limited robustness. This has led researchers to study
molecular sieve membranes, including carbon molecular sieve and zeolitic
materials. While these membranes offer very attractive properties, their cost,
difficulty of commercial scale manufacture, and brittleness remain major
challenges. Mixed membrane technology, which combines benefits of molecular
sieves with the ease and low cost of processing polymer membranes, offers a
potential solution to these challenges.