Post-Spinning Infusion of Poly(ethyleneimine) Into Polymer/Silica Hollow Fiber Sorbents for CO2/N2 Gas Separation

Post-spinning infusion of poly(ethyleneimine) into polymer/silica hollow fiber sorbents for CO₂/N₂ gas separation

Ying Labreche¹, Ryan P. Lively², Fateme Rezaei¹, Grace Chen¹, David S. Sholl¹, Christopher W. Jones^1,*, William J. Koros^1,*

¹ Georgia Institute of Technology, 311 Ferst Drive NW, Atlanta, GA 30332-0100, USA

² Algenol Biofuels, 28100 Bonita Grande Drive, Bonita Springs, Florida 34315, United States

Abstract

Amine-loaded hollow fiber sorbents for post-combustion CO₂recovery were created by utilizing a novel post-spinning infusion technique. This technique infused poly(ethyleneimine) (PEI) into cellulose acetate/mesoporous silica hollow fiber sorbents during the solvent exchange after spinning.  A suitable post-spinning infusing solution was found to be 10% PEI in methanol with an infusion time of 4 h.

After amine infusion, the 51 wt% silica hollow fiber sorbents were found to have a nitrogen loading of 0.52 mmol/g-fiber and a CO₂ uptake of 1.2 mmol/g-fiber at equilibrium.  The amine-loaded fibers were formed into a shell-and-tube module and exposed on the shell side at 1 atm and 35 °C to simulated flue gas with an inert tracer (10 mol% CO₂, 80 mol% N₂ and 10 mol% He at 100% R.H.).  The fibers were found to have a breakthrough CO₂ capacity of 0.58 mmol/g-fiber, with a mass transfer propagation front velocity of 1.12 cm/s. The CO₂ “equilibrium” uptake at 1 atm and 35 °C is 0.92 mmol/g-fiber. The sorption enthalpy release was monitored and the thermal front propagation velocity was 0.75 cm/s.  Finally, the water uptake was found to be 3.2 mmol/g-fiber.  The results indicate the post-spinning infusion method provides a new platform for ultimate scale-up of practical fiber sorbents for flue gas application.