以3D列印技術製備規模化高比表面積活性碳直接空氣捕捉二氧化碳之研究

Abstract

人為排放的二氧化碳對氣候變遷造成關鍵影響，而直接空氣捕捉 (Direct Air Capture, DAC) 是目前少數能從大氣中移除低濃度二氧化碳的關鍵技術，能有效彌補難以去碳化產業的排放，以及其他碳捕捉系統所遺漏的逸散二氧化碳。此外，其不受地點限制，適合模組化與規模化部署，有助於實現碳中和目標。因此本研究針對所需的吸附劑進行優化，利用間苯二酚-甲醛樹脂丙烯酸脂 (Methacrylate Resorcinol Phenolic Polycondensate, MRPP) 作為預聚物，並結合3D列印數位光處理技術 (Digital Light Processing, DLP) 製備高精度、高產率及低能耗之選擇性吸附活性碳 M-CX-Y，X為活化時間3、6、9小時，Y為氣體流速100、200 ml/min。 透過MSLattice程式設計形狀、結構、尺寸、晶胞大小及密度，以符合商用吸附管柱需求，最終選用具高比表面積、不間斷光滑曲線與低壓降的 Cylindrical Gyroid 結構。列印過程採用4K高解析度光固化設備，實現材料的高度可控性與精細結構。經不同碳化與活化條件處理後，製得M-CX-Y具備高比表面積 (>1,000 m2/g) 和高微孔率 (>90%)。在1atm、30℃、100% CO2條件下M-C6-200之二氧化碳吸附容量可高達2.44 mmol/g。於模擬煙道氣環境 (15% CO2/85% N2) 中觀察到M-C3-100具備優異的選擇性吸附能力，二氧化碳吸附量為1.393 mmol/g。在實際大氣環境中 (25~30℃，環境條件之CO2濃度，RH=90%) 下暴露24小時，M-C3-200模擬除濕機濾網可吸附達0.521 mmol- CO2/g。 本研究研發之M-C3-200擁有自動化及規模化生產能力，在原有抽氣設備中同時兼具選擇性吸附及分離大氣中二氧化碳之應用潛力，能減少建造成本及能耗，具備應用於DAC系統的前景，有望協助達成我國2050淨零碳排的目標。

Anthropogenic emissions of carbon dioxide (CO2) have a critical impact on climate change. Among various mitigation strategies, Direct Air Capture (DAC) is one of the few key technologies capable of removing low-concentration CO2 directly from the atmosphere. DAC can effectively compensate for emissions from hard-to-decarbonize industries and for fugitive CO2 not captured by other carbon capture systems. Furthermore, its location-independent nature allows for modular and scalable deployment, contributing significantly to achieving carbon neutrality. Therefore, this study focuses on optimizing the required adsorbent by employing methacrylate resorcinol phenolic polycondensate (MRPP) as a prepolymer. A high-precision, high-yield, and energy-efficient selective activated carbon adsorbent, denoted as M-CX-Y, was fabricated using digital light processing (DLP)-based 3D printing technology. In this nomenclature, X represents the activation time (3, 6, or 9 hours), and Y corresponds to the gas flow rate (100 or 200 mL/min). Structural modeling was conducted using the MSLattice program to design suitable shapes, structures, dimensions, unit cell sizes, and densities for commercial adsorption columns. A cylindrical gyroid geometry was selected for its high surface area per unit volume, continuous smooth curvature, and minimal pressure drop.The printing process utilized a 4K-resolution light-curing system with a 405 nm light source to achieve excellent structural control and fine resolution. After undergoing different carbonization and activation conditions, the resulting M-CX-Y materials exhibited high specific surface areas (>1,000 m2/g) and high microporosity (>90%). Under conditions of 1 atm, 30°C, and 100% CO2, the M-C6-200 sample achieved a CO2 adsorption capacity of up to 2.44 mmol/g. In a simulated flue gas environment (15% CO2/85% N2), M-C3-100 demonstrated outstanding CO2 selectivity with an adsorption capacity of 1.393 mmol/g. When exposed to real atmospheric conditions (25~30°C, Ambient CO2, RH = 90%) for 24 hours, M-C3-200, serving as a dehumidifier filter analog, was able to adsorb 0.521 mmol CO2/g. The M-C3-200 developed in this study demonstrates potential for automated and scalable production. It integrates selective CO2 adsorption and separation into existing vacuum systems, thereby reducing construction costs and energy consumption. This system shows strong promise for application in DAC technologies and may contribute to achieving Taiwan's 2050 net-zero carbon emissions target.