Molecular Engineering of Polymeric Membrane Materials for H2 Purification and CO2 Capture

Haiqing Lin

oGrowing evidence indicates that the CO2 emissions from the combustion of fossil fuels are contributing to global climate change.  One approach to controlling CO2 emissions to the atmosphere is carbon capture, utilization and sequestration (CCUS) from large point sources, such as H2 and power plants.  Pre combustion capture from syngas has been considered as an economically viable route.  In this scheme, gasification of fossil fuels produces syngas, which is further converted to CO2 and H2.  The CO2 must be removed and captured prior to H2 utilization for refinery hydrogenation reactions or combustion in the power plant turbines.

Membrane technology is an attractive approach to H2 purification and CO2 capture because of inherent advantages such as high energy efficiency.  This presentation will systematically examine the need of membrane technology as a low cost and energy efficient separation technology enabling the CCUS via pre combustion route.  I will discuss how we rationally design polymeric membrane materials to achieve the combination of high CO2 permeability and high CO2/H2 selectivity.  More specifically, this talk will discuss the molecular engineering of poly(ethylene oxide) (PEO) containing polymers for improvement in mixed-gas CO2/H2 separation performance.  Interestingly, these materials exhibit unconventional increase in mixed gas CO2/H2 selectivity as CO2 feed partial pressure increases.  The structure and property correlation in these PEO containing polymers will also be interpreted using a modified free volume model.  This talk will also provide a glimpse of how the molecular understanding in membrane material science can be translated to large scale membrane processes to solve practical problems.