Energy storage by plasma methane decarbonization for CO2-free synthesis of H2 & carbonaceous nanoparticles

天然气（甲烷）在加拿大能源组合中的份额正在迅速增加，这阻碍了能源脱碳。需要新的方法来使用甲烷资源，同时对环境的影响最小。等离子体分解是一种新兴的技术，用于在没有直接CO2排放的情况下破坏C-H键以产生氢和碳纳米颗粒。这项技术将电力储存在氢气中，并产生用于电池的有价值的碳纳米颗粒，即使不是零环境足迹，也是最小的。通过等离子体脱碳，大部分消耗的电力可以从氢气中回收，元素碳可以转化为有价值的纳米颗粒，而不会产生燃烧排放。这项技术尚未得到广泛应用，因为： 1. 人们对甲烷热解与等离子体化学的相互作用缺乏根本性的了解。燃烧动力学模型开发的甲烷氧化，只有少数反应占主导地位。然而，等离子体合成在没有氧气的情况下进行，对于氧气，其他重要的反应途径是活跃的。这种非氧化路线对工艺设计和新技术的开放可能性具有重大意义。 2. 碳质纳米颗粒的气相合成的知识仅限于窄范围的火焰温度。有了等离子体，这一范围就超出了燃烧的热力学限制，可以制造出一系列新的有价值的功能性纳米颗粒。等离子体合成的非氧化性质导致具有完全不同的组成、表面功能和光学性质的颗粒。由于理解上的差距和缺乏预测框架，目前无法预测这些参数如何随高温颗粒停留时间变化。 本研究通过多尺度实验和建模方法解决了许多这些问题，重点是等离子体化学与：a）甲烷热解动力学，B）高温气溶胶动力学和c）碳纳米颗粒的功能特性的相互作用。具体来说，我们将耦合甲烷和等离子体动力学模型与粒子模拟预测物种和气溶胶测量热解条件。然后，我们基准预测粒子的光学特性需要在过程控制中的激光诊断。最后，通过在模块化反应器中的实验，我们了解了碳纳米颗粒的功能特性是如何控制的。主要目标是揭示高温颗粒停留时间等工艺条件如何影响颗粒功能特性和氢气产量。 这项研究使加拿大能够通过将其巨大的碳氢化合物资源转化为氢和功能性纳米颗粒来利用其能源，这是无碳能源转换和储存的两种基本商品。它还有助于开发新的碳氢化合物重整技术，以减少排放。

The share of natural gas (methane) in Canadian energy portfolio is rapidly increasing which hinders energy decarbonization. Novel processes are needed to use methane recourses with minimal environmental impact. Plasma decomposition is an emerging technology for breaking C-H bonds without direct CO2 emissions to produce hydrogen and carbonaceous nanoparticles. This technology stores electricity in hydrogen and produces valuable carbonaceous nanoparticles used in batteries with minimal, if not zero environmental footprint. With plasma decarbonization, most of the consumed electricity can be recycled from hydrogen and the elemental carbon can be converted to valuable nanoparticles without combustion emissions. This technique has not been widely used because: 1. There is a fundamental lack of understanding regarding the interaction of methane pyrolysis with plasma chemistry. Combustion kinetic models are developed for methane oxidation where only a handful of reactions dominate. However, plasma synthesis operates without oxygen for which other important reaction pathways are active. Such non-oxidative routes have major implications for process design and open possibilities for novel technologies. 2. Knowledge of gas phase synthesis of carbonaceous nanoparticles is limited to a narrow range of flame temperatures. With plasma, this range is extended beyond thermodynamic limitations of combustion and an array of new valuable functional nanoparticles can be made. The non-oxidizing nature of plasma synthesis results in particles with completely different compositions, surface functionalities and optical properties. It is not currently possible to predict how these parameters change with high temperature particle residence time due to gaps in understanding and lack of a predictive framework. This research addresses many of these issues through a multiscale experimental and modeling approach with a focus on the interaction of plasma chemistry with: a) methane pyrolysis kinetics, b) high temperature aerosol dynamics and c) functional properties of carbonaceous nanoparticles. Specifically, we will couple methane and plasma kinetic models with particle simulations to predict species and aerosol measurements in pyrolysis conditions. Then we benchmark predicted particle optical properties needed for laser diagnostics in process control. Finally, with experiments in a modular reactor, we understand how the functional properties of carbonaceous nanoparticles are controlled. The main goal is to reveal how process conditions such as high temperature particle residence time affect particle functional properties and hydrogen production. This research enables Canada to harness the energy of its vast hydrocarbon resources by converting them to hydrogen and functional nanoparticles, i.e. two essential commodities for carbon free energy conversion and storage. It also contributes to developing novel hydrocarbon reforming technologies to reduce emissions.