- 學位論文
含氟矽烷疏水管狀陶瓷薄膜之製備與改質及其於二氧化碳捕捉之應用
Preparation and Hydrophobic Modification with Fluorocarbon Silane of Tubular Ceramic Membranes used for CO2 capture.
摘要
本研究主旨是在將具有耐化性、耐熱性與高機械強度的陶瓷管膜與陶瓷中空纖維膜製備成薄膜接觸器，並應用於燃燒後處理(Post-combustion capture) 的二氧化碳吸收裝置，研究中將探討陶瓷薄膜疏水程度會二氧化碳吸收通量的影響。 研究中先以FAS疏水改質劑對氧化鋁陶瓷管膜進行表面疏水改質，發現陶瓷管膜基材因孔洞較大，經表面疏水化後基收通量無法持續穩定，因此針對陶瓷管膜孔洞進行縮孔改質，以期可以提升陶瓷管膜的抗濕性與耐久性。在實驗中以溶膠凝膠法將中孔洞的二氧化矽氣凝膠成長於陶瓷管膜表面上，在經過疏水改質劑疏水化後的陶瓷管膜，成功延長二氧化碳吸收通量的穩定操作。 後續為了提高陶瓷薄膜的應用性，增加薄膜單位體積設備的填充密度，所以採用乾濕式紡絲法結合高溫燒結過程製備陶瓷中空纖維膜，以1：5的PES/Al2O3比例製備陶瓷中空纖維膜前驅物 ，並利用不同燒結溫度探討其孔洞大小與孔隙度對不同溫度的關係，可以發現經由燒結溫度1400°C所製備的陶瓷中空纖維膜有最高的孔隙度70％，而燒結溫度1600°C所製備的陶瓷中空纖維膜雖然孔隙度最低約54％，但是也得到最小的平均孔徑約0.2μm。 將高溫燒結後的陶瓷中空纖維膜以0.02M的疏水改質劑改質，成功的將親水的陶瓷中空纖維膜疏水化，而不同燒結溫度的陶瓷中空纖維膜疏水改質後，以燒結溫度最低的1400°C製備的纖維所得到的二氧化碳吸收通量最高約42*10-4(mole/m2s) ，以1500°C製備的陶瓷中空纖維吸收通量約38*10-4(mole/m2s) ，而1600°C製備的陶瓷中空纖維吸收通量最低約26.8*10-4(mole/m2s) ，三種溫度製備的陶瓷中空纖維疏水改質後皆有重複使用性，但在長時間操作方便以孔洞最小最均勻經過1600°C燒結的膜可維持長達4天的操作，經試驗後此溫度所製備的陶瓷中空纖維最適合應用於實場中。
並列摘要
The purpose of this study is using ceramic materials with chemical resistance, thermal stability and high mechanical strength to prepare a membrane as a membrane contactor for the capture of carbon dioxide in the post-combustion process. In this paper, we will explore the effect of the carbon dioxide removal efficient with degree of hydrophobic of membrane surface and membrane pore size. First of all, we used the fluoroalkylsilanes(FAS) to modify the surface of alumina membrane in order to raise the degree of hydrophobic. However, in the test of durability, the result was unsatisfactory because the modified membrane was wetted nevertheless. We found there are a number of reasons for the phenomenon of wetting. Therefore, we decided to shrink the membrane pore size for enhancing the membrane durability. As results, mesoporous SiO2 aerogels were successfully coated on macroporous Al2O3 membranes via a sol-gel process to shrink the pore sizes of the Al2O3 membranes for the study of CO2 absorption. And then, the membrane durability really was increase after the shrinkage process. Hollow fiber membrane contactors (HFMCs) offer a much larger contact area per unit volume compared to tray and/or packed columns. So we want to made a ceramic hollow fiber membrane contactor. And Al2O3 hollow fibre membranes were prepared by a combined phase-inversion and sintering method. Effects of Al2O3 particle size and size distribution, the sintering temperature on the structure and performance of the resulting membranes were studied And than we used the fluoroalkylsilanes(FAS) to modify the surface of ceramic hollow fiber membrane. We found that sintering temperature as 1400°C has the highest CO2 absorption flux. But the fiber sintering as 1600°C can be operated CO2 absorption continuously for long term periods.