Novel Thermally Rearranged Polymers for Olefin-Paraffin Separations

Olefins are the most important building blocks of the petrochemical industry. Approximately 50 billion pounds of ethylene and 30 billion pounds of propylene (worth an estimated $27 billion) were produced in the United States in 2009. The ethylene and propylene must be separated from their close-boiling paraffins, currently achieved using traditional low-temperature distillation, and energy and capital intensive process. The goal of this proposed project is to develop novel high performance membranes that separate olefins from paraffins under industrial conditions (hydrocarbon pressures up to saturation levels and temperatures of 60-120C). These membranes are based on newly discovered thermally rearranged (TR) polymers, which have strong size-sieving capabilities that can provide high olefin/paraffin selectivity. In Phase I, MTR will work with a group from the University of Texas Austin to make bench-scale TR-based composite membranes and modules, and test their separation properties with gases that model industrially-important olefin/paraffin streams. The data obtained will be used to determine the technical and economic feasibility of the membrane process, and prepare a Phase II work plan. In the Phase II project a pilot system will be constructed to evaluate the performance of industrial scale membrane modules. A field test will be carried out using the pilot system to demonstrate the membrane performance under real industrial conditions. A complete process design to integrate the membrane process with olefin production or recovery process trains will be developed based on the field test data, along with a commercialization plan.Commercial Applications and Other Benefits: Successful development of the proposed membranes could lead to bulk separation of the olefin/paraffin mixtures produced by steam cracking, which could substantially cut the energy consumption and reduce the cost of olefin production. Additional cost savings are expected from the use of the membrane technology in other applications, including the recovery of olefins from the purge gas streams of polyolefin plants and metathesis reactors, and the fluid catalytic cracker (FCC) off-gas streams of petroleum refineries