(518c) Ceramic-Carbonate Hollow Fiber Membranes with Improved Mechanical Strength for High Temperature CO2 Separation

Oxygen-carbonate ionic conducting ceramic-carbonate dual-phase membranes are permeable to CO₂ only, not other gases, at high temperatures (>600^oC). They have shown promises for applications in separation and reaction processes for hydrogen production and CO₂ capture. Ceramic-carbonate dual-phase hollow fiber membranes offer superb performance of CO₂ separation at high temperatures but suffer from poor mechanical strength. This paper reports a new structure of ceramic-carbonate dual-phase hollow fiber membrane with high CO₂ permeance and improved mechanical strength for CO₂ separation. The hollow fiber supports of about 1.4 mm OD and 1.0 mm ID are made of Ce_0.8Sm_0.2O_2-δ (SDC) and La₂NiO_4+δ (LNO) materials. The final hollow fiber membrane contains a SDC-carbonate outer layer and a SDC/LNO inner layer, forming a special double-ring structure in the middle of the membrane. The CO₂ flux of the membrane is 2.3 ml·min^-1·cm^-2 at 750 ^oC. In addition, the ultimate load and bending strength of the new SDC-SDC/LNO-carbonate hollow fiber membrane are respectively 3.6 and 1.9 times higher than that of pure single-layer SDC-carbonate hollow fiber membrane. This improvement of the mechanical strength can be attributed to special function of the double-ring structure.