(381m) CO2-Selective Facilitated Transport Membrane for Carbon Capture: Module Fabrication and Scale-up

Carbon capture from flue gas using membrane technology has been studied extensively to combat global warming. It is often a challenge to scale up the membrane fabrication from lab scale to pilot scale and, subsequently, make the membranes into modules. Using a roll-to-roll fabrication machine integrated with a knife-coating method, a 165-nm thick facilitated transport membrane was successfully made. The scale-up membrane had a width of 14 inches and a total length of > 1200 feet, and it was used to fabricate spiral-wound (SW) elements and modules.

In order to increase the membrane packing density in an element, an improved multi-leaf rolling procedure was developed. Although there is extensive literature on the fabrication of a multi-leaf SW membrane module, most of the studies had all the membrane leaves directly attached to the central permeate tube. Hence, the number of leaves would be limited by the surface area of the central tube. For improving the fabrication, only a carrier layer is attached to the central tube, and the membrane leaves were stacked on the carrier layer. Moreover, with a thinner spacer at 6 mil in thickness, the membrane area was increased to 2.94 m² in the most recent modules. The transport results of the modules agreed well with those of the flat sheet membrane under various testing conditions. For instance, a CO₂ permeance of 1450 GPU and a CO₂/N₂ selectivity of 185 were demonstrated consistently at 67°C. Also, satisfactory pressure drops were achieved.

A scale-up factor of >70 has been attained since the start of this study on SW element fabrication process. By considering the limitations set by concentration polarization and pressure drop, a predictive model was used to relate the operating conditions to the separation performances of the SW module. The experience gained is helpful to design a full-sized element (8 inches in diameter and 40 inches in length) for industrial application.

Dr. Salim’s current affiliation: Membrane Technology and Research, Inc. (MTR), Newark, CA

Dr. Wu’s current affliation: Liquid Microcontamination Control (LMC) Membrane R&D Group, Entegris, Bedford, MA