以厭氧程序轉換蔗渣為生質能源之研究

Abstract

本研究係利用蔗渣進行厭氧醱酵反應產生含碳數較低的揮發酸以及甲烷，並將反應所得含揮發酸之醱酵液作為鹼性燃料電池的基質，測試其發電的效能。 試驗的材料有二，一為由一般攤販取得之蔗渣，另一為台灣糖業公司提供之蔗渣，實驗中的菌種取自台灣大學動科系三段式牛糞尿處理系統中厭氧槽的沉澱污泥。醱酵實驗進行兩組操作條件：一為不同混合蔗渣比例的比較(共有4種比例)，另一為不同菌種濃度的比較(共有3種菌種濃度)。 試驗結果顯示蔗渣有相當的比例能被微生物分解，產物大多為揮發酸(乙酸與丁酸等短鏈揮發酸)或甲烷。同時利用試驗所得的揮發酸作為鹼性燃料電池基質的測試中顯示厭氧醱酵的酸液確實可以發電，唯如何提高酸的濃度以及發電的功率則有待進一步的探討。

In this study, bagasses were anaerobically digested to produce short chain volatile fatty acids (VFA) and methane. The fermented products – acidic effluent was then fed into an alkaline fuel cell as the substrate to test its performance in generating electric power. There were two sources of tested bagasses, one was obtained from market and another was from Taiwan Sugar Corporation. Seeds used for digestion were collected from the settled sludge of an anaerobic digester of the three-stage cow wastewater treatment system in Department of Animal Science and Technology, National Taiwan University. There were two groups of tests conducted in this study: one group was operated to compare the effect of different mixing ratios of bagasses from different sources (totally 4 levels), and the other group was operated to investigate the effect of different seeding concentrations (totally 3 levels). Experimental results showed that quite a lot of bagasses were degraded, and VFA (most were short chain acetate and butyrate) and methane were the major products. For the subsequent alkaline fuel cell performance tests, using the above acidic effluents as the substrate, results showed the fuel cell did generate electric power. The open circuit potential was achieved up to around 300 mV. However, further study is required to explore the measure to lift the VFA concentration and the efficiency of electrical power for fuel cell.