氧化鈣改質以提昇其捕獲二氧化碳溫室氣體之循環再生能力研究(II)

Abstract

二氧化碳捕獲及封存技術(Carbon dioxide Capture and Storage, 簡稱CCS) 為聯合 國IPCC 組織評估為未來可行且具成本效益之溫室氣體減量方案之一，據估計到2100 年時，全球將投入8,800~88,000 億美元至CO2 減量技術中。因此我國如果在CCS 技術 上能掌握技術先機，不僅可以有效減緩我國之CO2 排放，且可以將技術輸出國外，創造 出新商機。依文獻資料顯示，吸附為CCS 技術中較可行之技術之一，而在所有之吸附 材料中，CO2 吸附容量高、具選擇性、吸附速率高、大量存在且便宜的材料，當屬氧化 鈣(CaO)莫屬，但其卻有著容易劣化，導致再生次數少之缺點。 本計畫為兩年期計畫，在目前執行之第一年計畫中，係將CaO 以添加金屬改質方 式減緩其再生時的燒結問題，目前該計畫執行情形良好，研究結果發現，在添加5%之 有機鋁前趨物下，即可在反覆吸脫附後，獲致較未改質CaO 之CO2 吸附量提昇27%之 效益，該研究成果已投稿至SCI 國際期刊論文中，並已通過初步審查，獲致審查委員正 面之評價，預計修改後即可被接受。而第二年之計畫中，我們希望透過水合作用(hydration) 增加其孔洞體積，來減少其劣化速率，進而達到增加CO2 捕獲再生次數、降低CO2 吸 附成本之目的，並且採用國產之石灰石作為吸附劑並加以同步進行金屬及水合化改質， 以實際瞭解利用我國石灰石在經過物理與化學同步改質後，其對CO2 吸附之效能。於 研究中將藉由TGA 熱重分析及管柱式反應器進行CO2 反應再生吸脫附測試，來獲得反 應時間、水氣、CO2 進流濃度等對改質後CaO 吸附CO2 之吸附容量、吸附效率與再生 性之影響，並了解以水蒸氣作為脫附載流氣體之可行性。本計畫為國際上首先結合金屬 改質與水合作用之研究，預期本計畫結束後，將可發表至少三篇國際期刊論文，並具備 短期內即可進行模廠或實廠化測試之能力。

The Carbon-dioxide Capture and Storage (CCS) has been reported by the IPCC as one of the cost-effective means for CO2 greenhouse gas mitigation. It is estimated that by the year of 2100, the total expenditure on CO2 capture could be around $880~8,800 billions USD. Thus a new technological industry might be established if Taiwan can be in the leading position of CCS technologies. Literature data have shown that adsorption is one of the promising technologies for CO2 reduciton, of which the CaO chemical adsorption provides the advantages of high CO2 adsorption capacity, adsorption rate, and selectivity. In addition, the CaO is made from the abundunt limestone minerals thus its price is relatively cheaper. However, the disadvantage of CaO adsorption is that it is easily deteriated after cyclic adsorption. This is a two-year project. During the ongoing first year project, we have modified the CaO sorbent with aluminan metal to prevent the CaO from fast deterioration. The results showed that by adding only 5 wt. % of Ca12Al14O33 into the CaO sorbent, the CO2 sorption capacity can be enhanced by ca. 27 wt. % as compared to that of original CaO sorbent. And we have submitted a manuscript to the ASCE JEE journal and recently received positive comments from the reviewers. For the second year project, the hydration method will be employed and combined the the metal modification method to further increase the pore volume and decrease the sorbent capacity upon cyclic sorption. The cyclic adsorption will be performed by both TGA and column tests so that the reactor design parameters such as adsorption rate and adsorption capacity can be obtained, and the effects of humidity and CO2 inlet concentration can be studied. The novelty of this study relies on that it is the first attempt that combines the metal addition and the mesoporization process on CaO modification.