(22d) Transformational Membranes for Carbon Capture and Utilization

Capturing CO₂ from power plants and other industrial sources is key to reducing greenhouse gas emissions. Supported by the U.S. Department of Energy (DOE), GTI Energy and UB are developing graphene-oxide based membranes for CO₂ capture from a natural gas combined cycle (NGCC) flue gas. The recently developed membrane showed CO₂ permeance as high as 2,400 GPU with a CO₂/N₂ selectivity of 2,100, significantly higher than state-of-the-art membranes. The super high selectivity achieves ≥95% CO₂ purity by a single stage for typical NGCC flue gas (~4 vol% CO₂). The is development seeks to achieve DOE’s Transformational Carbon Capture performance goal of 95% CO₂ purity at a cost of $30/tonne of CO₂ captured.

Carbon dioxide can be utilized to produce renewable low-carbon fuels and high-value chemicals. Also supported by DOE, we are developing a unique catalytic membrane reactor for producing dimethyl ether (DME) from CO₂ and H₂. In our process, CO₂ and H₂ are fed to a hollow fiber membrane reactor which combines two reactions, methanol synthesis (CO₂ + 3H₂ à CH₃OH + H₂O) and methanol dehydration (2CH₃OH à CH₃OCH₃ + H₂O), into a one step process to produce DME. We have developed a revolutionary Na⁺ gated nanochannel membrane (Science, vol. 367, pp. 667, 2020) which removes water in situ, shifting thermodynamic equilibrium towards product formation, resulting a DME production rate of 630 g_DME/kg_cat/h at 250 °C. This rate is 2.4 times higher than the best results reported in the literature.