Reactor and catalyst modeling for direct hydrocarbon fuel cells

摘要-直接碳氢化合物燃料电池燃料电池将燃料的化学能转化为电能。从理论上讲，它们可以比传统发电厂更高效地实现这一目标。如果使用更少的燃料来产生相同数量的电能，那么向大气中排放的二氧化碳就会减少。据推测，这将减缓全球变暖和气候变化。理论上的考虑表明，使用目前正在开发的氢燃料电池无法实现这一期望。同样的分析表明，直接碳氢化合物燃料电池可以比氢燃料电池更节能，更环保。在这项技术中，碳氢化合物燃料直接在燃料电池的电化学反应中被消耗，而无需事先转化为氢、甲醇或任何其他物质。它有几个优点。它消除了对用于生产氢气的燃料处理器的需求。消除了吸热蒸汽重整引起的资金成本（占总成本的30%）和效率损失（占燃料能量的25%）。此外，直接碳氢化合物燃料电池比氢燃料电池具有更小的由熵变引起的效率损失（燃料能量的12%）。不幸的是，直接碳氢燃料电池有一个缺点。它们的电流密度很小，这意味着它们需要大型反应堆。该项目的目标是通过计算研究来了解和改进直接碳氢燃料电池的操作。具体来说，这个项目将(1)尝试通过使用密度泛函理论来识别改进的燃料电池电催化剂，(2)尝试通过使用计算流体动力学来识别改进的燃料电池反应堆结构和材料。通过进行计算研究，目的是确定材料、反应堆配置和操作程序，这些材料、反应堆配置和操作程序提供了足够有希望的性能，以保证后续的实验室实验研究。

Summary - Direct Hydrocarbon Fuel CellsFuel cells convert the chemical energy of a fuel to electrical energy.  Theoretically they can do this with greater energy efficiency than conventional electrical power plants.  If less fuel is used to generate the same amount of electrical energy, then there will be fewer emissions of carbon dioxide to the atmosphere.  Presumably this will diminish global warming and climate change.  Theoretical considerations indicate that this expectation cannot be achieved by using the hydrogen fuel cells currently being developed.  The same analysis shows that direct hydrocarbon fuel cells can be both more energy efficient and more environmentally friendly than hydrogen fuel cells.  With this technology a hydrocarbon fuel is consumed directly in the electrochemical reaction of a fuel cell, without previously being converted to hydrogen, methanol, or any other species.  It has several advantages.  It eliminates the need for a fuel processor that is used to produce hydrogen.  The capital cost (30% of the total) and the efficiency loss (25% of the fuel energy) caused by the endothermic steam reforming are both eliminated.  In addition direct hydrocarbon fuel cells have a smaller efficiency loss caused by entropy change (12% of the fuel energy) than hydrogen fuel cells.  Unfortunately direct hydrocarbon fuel cells have a disadvantage.  They have small current densities, which means they require large reactors.  The objective of this project is to understand and improve the operation of direct hydrocarbon fuel cells by performing computational studies.  Specifically this project will (1) try to identify improved fuel cell electrocatalysts by using density functional theory, and (2) try to identify improved fuel cell reactor configurations and materials by using computational fluid dynamics.  By performing computational studies, the intention is to identify materials, reactor configurations, and operating procedures that give a sufficiently promising performance in order to warrant subsequent experimental investigations in the laboratory.