GOALI: Thermo-catalytic Decomposition of Natural Gas Coupled with Regeneration: Nanostructure Connections and Control

氢气目前有几种用途，包括生产化肥、提炼和促进天然气燃烧发电。目前，用于这些用途的氢气是通过蒸汽-甲烷重整产生的，这是一个能源密集型过程，会产生大量二氧化碳，并消耗大量水。相比之下，甲烷的热驱动催化分解可以产生清洁的氢气，不受重整副产物的污染。热驱动催化分解利用大约一半的蒸汽甲烷重整输入能量来产生氢气。利用可再生能源，热驱动催化分解可以为基于氢燃料电池的发电和运输提供氢气，而不会产生二氧化碳。除了清洁的氢气外，热驱动催化分解还可以通过生产固体碳来有效地脱碳甲烷，可以促进向氢气经济的过渡。该项目通过夏令营和课外演示促进小学和高中学生对科学的投入。碳具有高温稳定性和抗中毒能力，是热驱动催化分解的理想催化剂。然而，它的活性随着反应时间的延长而下降。令人惊讶的是，沉积的碳纳米结构没有被显微镜观察到，也没有与其最初的活性和衰退有关。该项目的目标是通过将热驱动催化分解与作为催化剂的碳的再生反应相结合，实现热驱动催化分解为半连续过程。热驱动催化分解将使用代表真实管道混合物的合成天然气进行。再生将通过气化进行，使用二氧化碳或水，单独或作为混合物。该实验方法将系统地解决甲烷转化率、氢产率和产物选择性等热驱动催化分解指标以及关键动力学指标：反应速率、反应级数和活化能的反应参数及其相互作用。类似的方法将应用于再生反应，单独并与热驱动催化分解相结合。反应速率将与碳结构相关，从而形成热驱动催化分解和再生(气化)反应特有的结构-活性关系。热驱动催化分解和气化的动力学模型--都是由碳结构解析的--将使用开放源码的化学动力学建模代码与实验输入一起开发。从根本上说，这项研究试图将碳结构和活性联系起来，作为热驱动催化分解和气化反应的基本指标。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Hydrogen has several present-day uses including fertilizer production, refining, and boosting natural gas combustion for power generation. Presently hydrogen for these uses is generated by steam-methane reforming, an energy intensive process producing considerable carbon dioxide and consuming substantial water. In contrast thermally driven catalytic decomposition of methane can produce clean hydrogen uncontaminated by reforming byproducts. Thermally driven catalytic decomposition produces hydrogen using roughly half the input energy of steam methane reforming. Operating with renewable energy, thermally driven catalytic decomposition could supply hydrogen for power generation and transportation based on hydrogen fuel cells free of carbon dioxide production. Effectively decarbonizing methane by producing solid carbon in addition to clean hydrogen, thermally driven catalytic decomposition can facilitate the transition to the hydrogen economy. This project promotes elementary and high-school engagement in science though summer science camps and after-school demonstrations.Carbon is an ideal catalyst for thermally driven catalytic decomposition given its high temperature stability and resistance to poisoning. Yet its activity declines with reaction time. Surprisingly, deposited carbon nanostructure has not been examined by microscopy nor connected with its initial activity and decline. The project goal is to realize thermally driven catalytic decomposition as a semi-continuous process via coupling thermally driven catalytic decomposition with a regeneration reaction for the carbon serving as catalyst. Thermally driven catalytic decomposition will be conducted using synthetic natural gas representing realistic pipeline mixtures. Regeneration will be conducted by gasification, using carbon dioxide or water, separately or as mixtures. The experimental approach will systematically resolve reaction parameters and their interactions upon thermally driven catalytic decomposition metrics of methane conversion, hydrogen yield and product selectivity and key kinetic metrics: reaction rate, reaction order and activation energy. A similar approach will be applied to regeneration reactions, individually and coupled with thermally driven catalytic decomposition. Reaction rates will be correlated with carbon structure, thereby developing structure-activity relationships specific to both thermally driven catalytic decomposition and regeneration (gasification) reactions. Kinetic models for thermally driven catalytic decomposition and gasification – both resolved by carbon structure, will be developed with experimental input, using an open-source chemical kinetic modeling code. Fundamentally, this study seeks to connect carbon structure and activity as a fundamental metric for thermally driven catalytic decomposition and gasification reactions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.