高溫CO2 捕捉與轉化--新穎奈米層狀與複合奈米材料設計及研發( I )

Abstract

為了人類永續發展 過度的消耗石化燃料與不付責任的二氧化碳釋放造成地球溫 度上升已經成為高度關心的議題。由於京都會議書的協定內容，使有關二氧化碳 捕捉與處理的科技研究已經吸引世界各地高度關注。為了滿足這個挑戰，此協議 書提供一個合理的策略，在中高溫環境下經由創新的固態吸附劑和觸媒，去捕捉 和再利用碳。 為了有效解決這方面的問題本研究計畫將結合整合氣化複合式循環 (Integrated Gasification Combined Cycle (IGCC)的優勢，去移除由電廠產生的大量 二氧化碳，這將會對二氧化碳排放產生相當重要的效應。此研究計畫主要是由四 個相互獨立的子計劃共同研發以達成此計畫目標。而每一個子計畫都是經過周詳 地計畫且有明確的目標。 在子計畫-1，主要是在發展高效率中高溫CO2 吸脫附之高比表面積中孔洞鈣 摻雜層狀水滑石(Ca-based LDH)粉體的最佳製程，並且研究其對於二氧化碳吸脫 附行為與相關的動力學。同時經由製程調控及元素的改變來研發在不同中高溫溫 度下的具有最佳CO2 吸脫附形為及再重覆利用及低成本的組成配方，以應用火 力發電到石化鋼鐵的CO2 吸脫附。並探討不同複合陶瓷結構之無機厚膜，對二 氧化碳和氫氣的吸附與分離性影響。在另外一方面將配合核能研究所建立高溫除 碳反應器，進行二氧化碳氣體捕獲最適當實驗條件，以期與核研所建立除碳與及 CO2/H2 的分離再利用先導系統建置之學術基礎。 在子計畫-2，我們將致力於設計且製造出一具有高氫氣與二氧化碳分離效率 之金屬及質子傳導材料複合薄膜，以用於中高溫環境下之氫氣純化，研究中將探 討氫氣於表面之吸附解離反應，以及質子於氧化物中之擴散作用與其晶體組成之 關係，並結合氣氛式熱處理與微觀結構等分析，了解其於實際操作環境中之長期 穩定性和可能遭遇之問題，以最佳化其組成並提升其操作潛力。 在子計畫-3，我們將製作一個以固態氧化物作為電解質之燃料電池，預計利 用子計畫一及子計畫二所分離出來之氫氣作為燃料，藉由合成新型的陽極觸媒催 化劑將氫氣與陰極之氧氣結合成為水而進行發電，本子計畫將利用實驗室中過去 所累積之燃料電極製程及組裝技術進行效能的提升。 在子計畫-4，為了暸解二氧化碳減量反應中的高光催化活性，我們將利用已 知用於合成與鑑定在孔洞中填入二氧化鈦的光催化專門技術。除此之外，我們會 投入發展並且設計出理想的以光纖為基底的反應器，如同把二氧化鈦披覆於光纖 上，使得二氧化碳與水產生光還原作用。 最後，整合各子計畫使整個二氧化碳捕捉與移除系統更有效率，同時並達到 氫氣的純化(高效率捕碳)，以應用於燃料電池，來提高能源效率，同時透過光催 化，來進二氧化碳轉化成甲醇，以達到減碳及再利用的計畫目標。

Excessive consumption of fossil fuels and irresponsible emission of CO2 into atmosphere has lead to rising ambient temperature that has caused significant concerns over sustainability of mankind. Upon imposition of Kyoto Protocol, technologies that are able to capture and dispose CO2 have attracted considerable attentions worldwide. To address this challenge, this proposal provides a cohesive strategy to carbon capture and reuse at mid-to-high temperature via employment of novel solid absorbers and catalysts for conversion reactions. The proposed solution is intended to combine with Integrated Gasification Combined Cycle (IGCC) to remove large quantity of CO2 at the power generation plants so its impacts over CO2 emission will be rather critical. This proposal includes three sub-projects that are interdependent. Each sub-project is well-planned with clear and ambitious objectives. In subproject I, we intend to carry out synthesis and structural characterization for nanoporous Ca-doped layer double hydrates (Ca-based LDH), study CO2 sorption behavior and related kinetics in mesoporous Ca-based LDH membranes, as well as absorption and separation of CO2, and H2, for Ca-Al-LDHs in various Ca/Al ratios. To identify the optimized conditions for CO2 separation and capture high temperature de-carbonizing reaction fabricated by INER will be performed. In sub-project II, we will aim to design and produce a metal-ceramic composite membrane which has high efficiency to separate hydrogen from H2/CO2 mixed gases, and apply it into hydrogen purification at medium-high temperature. The absorption-dissociation reactions of hydrogen on membrane surface and relationship between diffusion behavior and the crystal composite will both be studied. We will also combine the heat treatment in different atmospheres and microstructure analysis to realize the practical issues, like long-term reliability, and optimize its composite and enhance its application potential. In sub-project III, we will make a fuel-cell which uses solid oxide as its electrolyte. Hydrogen that separated from sub-project I and sub-project II will be used as its fuel source. Novel oxide electrocatalytst will be explored for enhanced catalytic activities. Our past experiences in fuel cell fabrication and associated techniques will be very helpful ensuring successful execution of this sub-project. In sub-project IV, we intend to employ known photocatalysis expertise in the synthesis and characterization of porous doped TiO2 in order to realize high photocatalytic activity for CO2 reduction. In addition, we will engage in the development and structural optimization of an optical fiber-based reactor for efficient CO2 reduction, as well as deactivation of the TiO2 coated optical fiber reactor for photoreduction of CO2 with water. Lastly, efforts will be devoted to system optimization with all sub-projects to streamline the entire CO2 capture and removal process. It is expected to explore the possibility for CO2 capture and conversion in a single unit system, and to establish the fundamental understanding of CO2 removal and reuse from academic standpoints