Adsorption processes in highly microporous nanostructures for advanced energy and environmental technologies

高微孔吸附剂在开发更绿色、更高效的能源和环境技术方面发挥着关键作用。它们可用作变压吸附（PSA）系统中的活性剂，以净化沼气，提高与天然气基础设施和能源技术的兼容性，从烃流中提取氢气，提高石油工业气体重整技术的能源效率，或从废物中提取氢气，用于零直接排放发电。PSA还可用于从废气中去除温室气体和污染物，以进行封存或处置。微孔吸附剂也可用于可逆低压和安全储存气体燃料，如甲烷和氢在高能量密度。 基于吸附的应用的设计需要能够准确地预测与气体移动通过由高度微孔颗粒制成的多孔粉末的动力学相关的复杂流体力学现象，同时经历非线性地依赖于温度并且产生显著热效应的吸附过程。从微观到宏观的综合多尺度方法原则上可以确定吸附剂的最佳微观和宏观性质，作为特定于应用的目标操作条件（压力、温度、流动条件）和待处理气体的函数。 这些建议的目的是（1）开发多尺度集成方法，该方法将使用统计物理学来桥接吸附过程的微观计算，以根据已知的纳米结构和相互作用来预测新纳米结构在宽范围的热力学条件下的吸附等温线，吸附等温线模型的发展（吸附状态方程），其特征在于可以与微观性质相关的最小数量的物理上有意义的可调节参数，以及系统的计算机流体力学（CFD）模拟（气体储存和纯化/分离），以确定应用特定的最佳操作条件、热管理和几何形状;（2）通过优化模型等温线，基于CFD系统模拟确定最佳吸附剂性能范围，以指导新多孔纳米结构的开发（逆向工程）和（3）进一步理解在极端热力学条件下（与氢的吸附储存相关）的超临界状态（T>Tc）下的物理吸附，特别是超临界状态下吸附密度的饱和极限。

Highly microporous adsorbents are playing a key role in the development of greener and more efficient energy and environmental technologies. They can be used as active agents in pressure swing adsorption (PSA) systems to purify biogas to improve compatibility with natural gas infrastructure and energy technologies, to extract hydrogen from hydrocarbon streams to improve the energy efficiency of gas reforming technologies for the oil industry or to extract hydrogen from waste for zero direct emission electric power generation. PSA can also be used to remove greenhouse gases and contaminants from effluent gases for sequestration or disposal. Microporous adsorbents can also be used for the reversible low-pressure and safe storage of gaseous fuels such as methane and hydrogen at high energy densities. The design of adsorption-based applications requires the ability to accurately predict the complex fluid mechanics phenomena associated with the kinetics of gases moving through porous powders made of highly microporous pellets, while undergoing adsorption processes that depend non-linearly on temperature and that generate significant thermal effects. An integrated multi-scale approach, from the microscopic to the macroscopic, can in principle determine optimal microscopic and macroscopic properties of adsorbents as a function of target operating conditions (pressure, temperature, flow conditions), specific to the application, and of the gases to be processed. The objectives of this proposals are (1) to develop a multiscale integrated approach that will bridge microscopic calculations of the adsorption process using statistical physics to anticipate the adsorption isotherms of new nanostructures over wide ranges of thermodynamic conditions from known nanostructures and interactions, the development of adsorption isotherm models (equations of state of adsorption) characterized by the smallest number of physically meaningful adjustable parameters that can be correlated to microscopic properties, and computer fluid mechanics (CFD) simulations of systems (gas storage and purification/separation) based on the isotherm models to determine application-specific optimal operating conditions, thermal management and geometries; (2) to determine optimal adsorbent properties ranges based on CFD system simulations by optimizing model isotherms to guide the development of new porous nanostructures (reverse engineering) and (3) to further the understanding of physisorption in the supercritical state (T>Tc) under extreme thermodynamic conditions (relevant to adsorption storage of hydrogen), notably the saturation limit of the adsorbed density in the supercritical state.