Published October 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.