氧化鈣改質製備層狀材料並應用於高溫CO2捕獲程序

Modification of CaO Materials to Produce Lamellar Structure and Its Application as Sorbent to High Temperature CO2 Capture Procedure

本研究利用改質氧化鈣製備碳捕捉材料，並比較醋酸鈣、氯化鈣等前驅物合成捕碳劑之CO2捕獲效果。醋酸鈣所獲得的材料表面積最大，而氯化鈣所獲得的材料的表面積較小。改質前CaO 具有低表面積與較差的高溫捕碳穩定性，利用具有層狀結構之鈣鋁碳酸鹽進行CaO 改質可顯著提升其捕捉特性。改質後CaO 表面具有此層狀結構，經高溫煅燒形成多孔鈣鋁氧化物，因此促進材料的CO2捕獲性能。利用熱重分析儀測試捕碳性能，以醋酸鈣為前驅物所獲得的材料表現最佳，改質氧化鈣表現也相當優異，此二者捕碳性能皆優於氯化鈣衍生材料。其中以改質CaO 獲得最佳結果，在750°C通入100% CO2條件，以TGA 測試具有51.37 wt%的初始CO2捕捉量，40 次吸脫附循環穩定性由50%提升至96.14%。本研究證實了以氧化鈣為前驅物合成碳捕捉材料並應用於高溫CO2捕獲反應的可行性。

In this study, a method of fabricating CO2 sorbents is developed,including calcium acetate (CA) and calcium chloride (CC) derived materials,and CaO modified (CM) sorbents. The nature of these sorbents wascharacterized by Brunauer-Emmett-Teller (BET) surface area analyzer andpowder X-ray diffraction (XRD). BET analysis showed that the surfacearea of CA was higher than that of CC. The original CaO material exhibiteddisadvantages for CO2 capture performance at elevated temperatureconditions, including low surface area and poor long-term stability. How- ever, these defects can be significantly eased via modification of CaO toproduce calcium aluminate carbonates with lamellar structure. XRDpatterns indicated that fresh CM had a lamella structure, which became aporous calcium alumina mixed oxide after calcination and thus improvedCO2 capture performance of sorbents. In TGA tests, both CA and CMdisplayed superior CO2 capture capacity compared to CC. Among them,CM is the best candidate for CO2 capture, demonstrating 51.37 wt% ofcapacity with high recovery of 96.14% maintained for 40 cycles at 100%CO2 and 750°C conditions. The results confirm the potential for usinglow-cost CaO as a high-temperature CO2 sorbent.