Scale-up and field testing of nanoconfined ionic liquid membranes for CO₂ capture from real flue gas

Nanoconfined ionic liquid (NCIL) membranes emerge as a highly promising candidate for gas separation due to the high-pressure durability, high gas selectivity, and ease of regeneration. However, the scalability and stability of liquid-based membranes for practical applications remain debatable. Herein, we demonstrated an industrially viable NCIL membrane for efficient CO₂ capture from real coal-fired flue gas, via conducting a field testing using 1000 cm² hollow fiber membrane modules at the National Carbon Capture Center (NCCC) in Wilsonville, AL, USA. Prior to the field testing, the gas separation performance was systematically evaluated using simulated flue gas to determine the optimal membrane structure and operation conditions. When using real flue gas in field testing, the membrane module demonstrated excellent and stable gas separation performance with stage cut for 8 days, with a log-mean CO₂ permeance of 525 GPU and CO₂/N₂ selectivity of 488 at 70 °C. Apart from high CO₂ capture rate up to 47 %, the membrane was capable of elevating the CO₂ dry-basis purity from 10.4 % to 97 % in a single stage. The field-testing results represent the first successful module-level demonstration of NCIL membrane system and further validate its potential for industrial CO₂ separation. Furthermore, this scale-up process is expected to serve as a platform or template for scaling up other task-specific liquid-based (TSIL) membranes, while largely mitigating the effects of substrate quality.