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

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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.