| Summary: | 碩士 === 元智大學 === 機械工程學系 === 103 === This study evaluates the performances of the novel Mg-based canisters coupled to power the proton exchange membrane fuel cells (PEMFC). Home-made Mg-based powders (~4g) were inserted into a stainless steel reactor equipped with a Cu foam to enhance the heat transfer during hydrogenation and dehydrogenation. Commercial H-pulverized LaNi5-based powders (20g) were also tested in the same reactor for comparison. The hydriding performances of Mg-based and LaNi5-based canisters were measured in the fixed H2-flows from 100 to 500 ml/min, while the dehydriding performances of them were tested in a fixed H2-flow of 25 ml/min. First, the LaNi5-based canister absorbed hydrogen amount of 2995 ml (equivalent to 1.2 wt%) within 10 min at room temperature, and desorbed 2904 ml (equivalent to 1.2 wt%) at same temperature. A PEMFC (MEA area = 7.3 cm2) was powered by a constant H2 flow of 25 ml/min released from the H-charged LaNi5-based canister, and a constant air flow of 120 ml/min. The PEMFC results in a test period of 80 min showed that the output current was 0.8 A in a mode of fixed voltage of 0.5 V, producing an average conversion of H2 energy into electricity of 10%. On the other hand, the Mg-based canister absorbed hydrogen amount of 1194 ml (2.3 wt%) within 5 min at room temperature in a fixed H2 flow of 500 ml/min. When the hydrogenation temperature increased to 100 and 300oC, the amounts of hydrogen absorption increased to 2070 (4.0 wt%) and 2280 ml (4.4 wt%), respectively. At hydrogenation temperature of 100oC, for example, the H content stored in the Mg-based canister released at a constant H2 flow of 25 ml/min at 360oC to power a PEMFC. The resulting output current was 0.8 A in a mode of fixed voltage of 0.5 V. The average conversion of H2 energy into electricity was same to 10% obtained in the case of LaNi5-based canister. Compared to literature reports, the Mg-based canister developed in this study exhibited a unique advantage of hydrogenation ability at room-mild temperatures. It was expected that this H2 canister may have potential in applications in the field of on-site power generations.
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