By Bruce A. Wilcox
Published Octrober 2003
The carpet fibers market, historically dominated by nylon, and to a lesser
extent, polyester based products. It is now being challenged by polytrimethylene
terephthalate (PTT) fibers, which have superior attributes. Although these
benefits have been known for decades, technology has recently been developed
to overcome the traditional impediment to widespread adoption of PTT carpet
fibers, mainly the cost of manufacturing its 1,3-propanediol (PDO) precursor.
Shell has recently patented a novel catalyst/solvent technology that improves
the yield and selectivity of ethylene oxide (EO) conversion to PDO beyond
that indicated in their previous patents. In this review, SRI evaluates the
economics of this new technology and its implications to substitute products
in the carpet fiber market.
An economic analysis based on a theoretical process using this new Shell technology
indicates that PDO can be produced for 83 ¢/Lb. at a 100 MM Lb./Yr. facility,
a price that should be cost competitive with existing and near term PDO manufacturing
routes. At this price for PDO, the product value of PTT would decrease to
69 ¢/Lb., well below that of Nylon 6, at 101¢/Lb., but higher than
polyester, at 46 ¢/Lb. Further reductions in PDO capital investment and
energy usage through solvent optimization could further reduce the price of
PDO.
