乙醇之合成與轉化: 在可再生能源供應鏈中的作用

Abstract

當前全球暖化和能源危機嚴峻，迫切需要從化石燃料轉向可再生能源，以減少碳排放並確保可持續的能源安全。本研究探討乙醇作為能源載體及燃料的雙重角色，在碳捕獲和利用（CCU）概念下，對提升能源存儲和運輸效率具有重要意義。研究重點在於澳大利亞（出口國）與台灣（進口國）之間的假想能源供應鏈。在出口國，利用可再生電力進行電解製氫，隨後將氫轉化為乙醇。乙醇運送到台灣後，進行ethanol reforming生成適用能源應用的高純度氫氣。Ethanol synthesis 和ethanol reforming過程均通過Aspen Plus軟件進行模擬和優化，以確保最大化效率和成本效益。經濟分析涵蓋整個供應鏈，包括電解製氫、ethanol synthesis、ethanol reforming和運輸成本。研究顯示，reformed hydrogen的單位成本為7.49 $/kg-H2，高於electrolyzed的2.70 $/kg-H2，主要原因是ethanol synthesis和ethanol reforming中額外的處理步驟和能量需求。整個供應鏈的氫氣轉換效率為63.5%。在假設每公斤氫的價格為10美元的情況下，預計回收期為3年。總結來說，本研究表明，在可再生能源供應鏈中，乙醇作為技術上可行且經濟上可行的能源載體具有重要潛力。其能夠與CCU策略無縫集成，實現高純度氫氣的生產，進一步推動全球能源轉型和減少碳排的倡議。

Global warming and the energy crisis present critical challenges in today’s world, necessitating a rapid transition from fossil fuels to renewable energy sources to mitigate carbon emissions and ensure sustainable energy security. The research focuses on a hypothetical energy supply chain between Australia (exporter) and Taiwan (importer). In the exporter, renewable electricity is used to produce hydrogen, which is then converted into ethanol. Upon transport to Taiwan, ethanol undergoes reforming to generate high-purity hydrogen for various industrial and energy applications. The processes of ethanol synthesis and reforming are simulated by Aspen Plus. Economic analysis covers the entire supply chain, including costs associated with electrolysis, ethanol synthesis, ethanol reforming, and transportation. The study reveals that the unit cost of reformed hydrogen is 7.49 $/kg-H2, which is higher than that of electrolyzed hydrogen (2.70 $/kg-H2), primarily due to additional processing steps and energy requirements in ethanol conversion and reforming. Furthermore, the overall hydrogen conversion across the supply chain is 63.5%. A payback period of 3 years is estimated at a hydrogen price of 10 $/kg. In conclusion, this study demonstrates that ethanol holds promise as a technically viable and economically feasible energy carrier within the renewable energy supply chain. Its ability to integrate with CCU strategies and achieve high hydrogen purity underscores its potential role in advancing global energy transitions and contributing to carbon reduction initiatives.