RO Membrane Cuts Energy Consumption of Separations

Engineers at the Georgia Institute of Technology and ExxonMobil have developed a carbon-based membrane that could cut the energy consumption required to separate liquid hydrocarbons.

The new membrane is made of bundles of hollow carbon fibers that can be used in organic solvent reverse osmosis (OSRO) to separate hydrocarbon molecules by size. The team used the membrane to separate xylene isomers, including para- and ortho-xylene.

Downstream chemical processes commonly employ energy-intensive techniques such as crystallization and simulated moving-bed adsorption to separate alkyl aromatics from other liquid hydrocarbons. The separation of xylene isomers from one another is especially challenging because their physical properties (e.g., boiling point, molecular weight) are similar. Membrane-based techniques are being explored to lower the energy requirement of these separations. Organic solvent nanofiltration, for example, has emerged as a potential technology. However, the materials used for organic solvent nano-filtration membranes are unable to efficiently separate molecules of similar size. For this reason, the engineers, led by Dong-Yeun Koh, a postdoc of chemical and biomolecular engineering at Georgia...