Hayouk Eyal, Schechter Alex, Avrahami Idit
Department of Mechanical Engineering & Mechatronics, Ariel University, Ariel, 40700, Israel.
Department of Chemical Sciences, Ariel University, Ariel, 40700, Israel.
Heliyon. 2024 Feb 8;10(4):e25744. doi: 10.1016/j.heliyon.2024.e25744. eCollection 2024 Feb 29.
Hydrogen-based Fuel Cells (FCs) hold significant potential as energy conversion technologies. In a previous study, we presented a pump-based hydrogen generator (PHG) that utilizes a catalytic reaction between sodium borohydride (NaBH) powder and water. The pump circulates the water solution through the powder chamber in a closed-loop reaction. The PHG demonstrated clear advantages over alternative hydrogen sources in terms of both safety and energy density. However, as operating time increases, the solution in the closed-loop PHG becomes saturated, causing the reaction rate to decline. This limitation can be overcome in cases where an external water source is available, such as marine vehicles, drones equipped with water recovery systems from their fuel cells, or systems located near pipelines. In such scenarios, introducing freshwater feeding and product emission offers intriguing possibilities for significantly enhancing the fuel's energy density and extending its effective operation time. Our current research introduces an innovative concept: a dual-cycle generator (DCG) that effectively overcomes the issue of solution saturation over time. It achieves this by combining solution circulation with freshwater feeding and product emission. Our study employed a DCG prototype to examine various operating modes and to demonstrate the effectiveness of this approach. The DCG achieved a calculated energy density for the fuel of 3868 Wh/kg, with 93% H extraction yield from the powder. Our findings reveal substantial improvements in terms of extended operation duration (81%), increased hydrogen flow rate (36%), enhanced energy density (33%), and improved H yield extraction from the powder (39%). This methodology holds promise for mobile applications or off-grid systems situated in proximity to a water source.
氢燃料电池（FCs）作为能源转换技术具有巨大潜力。在之前的一项研究中，我们展示了一种基于泵的氢气发生器（PHG），它利用硼氢化钠（NaBH）粉末与水之间的催化反应。泵使水溶液在闭环反应中循环通过粉末腔。在安全性和能量密度方面，PHG相较于其他氢气源展现出明显优势。然而，随着运行时间增加，闭环PHG中的溶液会饱和，导致反应速率下降。在有外部水源的情况下，如船舶、配备燃料电池水回收系统的无人机或靠近管道的系统，这种限制可以被克服。在这种场景下，引入淡水补给和产物排放为显著提高燃料的能量密度和延长其有效运行时间提供了有趣的可能性。我们当前的研究引入了一个创新概念：一种双循环发生器（DCG），它能有效克服溶液随时间饱和的问题。它通过将溶液循环与淡水补给和产物排放相结合来实现这一点。我们的研究采用了DCG原型来研究各种运行模式，并证明这种方法的有效性。DCG实现了燃料计算能量密度为3868 Wh/kg，从粉末中提取氢气的产率为93%。我们的研究结果显示，在延长运行持续时间（81%）、提高氢气流量（36%）、增强能量密度（33%）以及提高从粉末中提取氢气的产率（39%）方面有显著改善。这种方法对于靠近水源的移动应用或离网系统具有前景。
