CO2-philic Block Copolymers with Intrinsic Microporosity for Postcombustion CO2 Capture

Reducing CO2 emissions from coal-fueled power plants is widely viewed as a key element in mitigating global warming. However, adoption of proven CO2 capture technologies is constrained by high cost, which would increase the price of electricity beyond acceptance.A novel, step-change membrane is being developed in this project that can significantly reduce the CO2 capture cost.The approach in Phase I was to develop new membrane materials and scalable membranes based on block copolymers (BCPIMs) of rubbery poly(ethylene oxide) (PEO) and polymerizable metal-organic frameworks (polyMOFs) with superior CO2/N2 separation properties. The membranes that were developed, achieved a CO2 permeability target of ≥2,000 Barrer, a CO2/N2 selectivity target of ≥40 and showed good stability in the presence of water vapor, SOx, and NOx. Thin-film composite (TFC) membranes, including the selective layer, a highly permeable, polymer gutter layer, and a microporous substrate were fabricated and tested to confirm proof-of-concept. The separation properties were shown to be independent of the feed gas compositions and pressures, demonstrating their potential for flue gas treatment. A preliminary techno-economic analysis (TEA) was performed based on the projected commercial TFC membrane module performance of the new BCP-MOF materials synthesized in Phase1. The capture cost was projected to be as low as $20-22/ton, which is less than the U.S. Department of Energy’s nominal target of ~$30-40/ton. CO2 purities of 78-90% can be achieved with membranes alone, but adding a cryogenic back end can increase the product purity to ~100% at an added cost of ~$8-10/ton. Phase II plans focus on optimizing the TFC membrane for CO2 permeance ≥4,500 GPU and CO2/N2 selectivity ≥40, scaling-up TFC membrane fabrication, conducting long-term testing of membrane resistance to contaminants, fabricating small modules, validating process performance, defining the optimal CO2 capture process, and refining the TEA. Development and commercialization of this cost-effective CO2 membrane capture process technology will create domestic jobs and promote economic growth, while reducing global warming.