Preparation And Performance Of Ceramic-Carbonate Dual Phase Hollow Fiber Membrane For Co₂ Separation

Ceramic-carbonate dual phase membrane is a kind of material for direct CO₂ capture at high temperature（500～1000°C）.Most of the research on dual phase membranes are devoted to improving the CO₂ permeation flux and separation efficiency of the membranes,but ignore the limitations of mechanical strength and long-term stability on the commercial application of the membrane.The single-layer Ce_0.8Sm_0.2O_2-δ（SDC）-carbonate dual-phase hollow fiber membrane has good CO₂ permeation flux,but its mechanical strength is poor.Therefore,in this paper,a ceramic-carbonate hollow fiber membrane with a double-layer structure was designed to improve the mechanical strength and long-term stability of the membrane while also achieving good CO₂ separation efficiency.In this thesis,Ce_0.8Sm_0.2O_2-δ（SDC）Materials and La₂NiO_4+δ（LNO）material were selected as the ceramic phase of the film.Due to the differences in thermal expansion performance and carbonate wettability between the two types of powders,this study first successfully prepared a sheet-like SDC-SDC/LNO-carbonate dual phase membrane with an asymmetric structure through one-step co pressure sintering method.The compatibility matching problem of the bonding process of the two materials was explored,and the optimal mixing ratio of SDC and LNO powders was determined by experiments.The results show that the SDC-SDC/LNO-carbonate membrane prepared with the mass ratio of SDC:carbonate=5:1 and SDC/LNO/carbonate=3:3:1 has good CO₂ separation performance.Under a 50%N₂-50%CO₂ atmosphere,the maximum CO₂permeation flux of the membrane can reach 0.161 m L·min^-1·cm^-2 at 750℃.On this basis,the double-layer SDC-SDC/LNO-hollow fiber support was further prepared by two-step phase inversion method,and the support was infiltrated by“carbonate coating method”.This method can effectively control the distribution of molten carbonate in the support,and finally form a special“double-ring double-layer”structure at the junction of SDC outer layer and SDC-SDC/LNO layer of the membrane.This double-layer structure allows the membrane to maintain good CO₂ permeability while improving mechanical strength and long-term stability.