Risk Minimization in Scale-Up of Biomass and Waste Carbon Upgrading Processes.

Improving the odds and pace of successful biomass and waste carbon utilization technology scale-up is crucial to decarbonizing key industries such as aviation and materials within timelines required to meet global climate goals. In this perspective, we review deficiencies commonly encountered during scale-up to show that many nascent technology developers place too much focus on simply demonstrating that technologies work in progressively larger units ("profit") without expending enough up-front research effort to identify and derisk roadblocks to commercialization (collecting "information") to inform the design of these units. We combine this conclusion with economic and timeline data collected from technology scale-up and piloting operations at the National Renewable Energy Laboratory (NREL) to motivate a more scientific, risk-minimized approach to biomass and waste carbon upgrading scale-up.

Rigid Arrangements of Ionic Charge in Zeolite Frameworks Conferred by Specific Aluminum Distributions Preferentially Stabilize Alkanol Dehydration Transition States.

Zeolite reactivity depends on the solvating environments of their micropores and the proximity of their Brønsted acid sites. Turnover rates (per H ) for methanol and ethanol dehydration increase with the fraction of H sites sharing six-membered rings of chabazite (CHA) zeolites. Density functional theory (DFT) shows that activation barriers vary widely with the number and arrangement of Al (1-5 per 36 T-site unit cell), but cannot be described solely by Al-Al distance or density.

Cooperative and Competitive Occlusion of Organic and Inorganic Structure-Directing Agents within Chabazite Zeolites Influences Their Aluminum Arrangement.

We combine experiment and theory to investigate the cooperation or competition between organic and inorganic structure-directing agents (SDAs) for occupancy within microporous voids of chabazite (CHA) zeolites and to rationalize the effects of SDA siting on biasing the framework Al arrangement (Al-O(-Si-O)-Al, = 1-3) among CHA zeolites of essentially fixed composition (Si/Al = 15). CHA zeolites crystallized using mixtures of TMAda and Na contain one TMAda occluded per cage and Na co-occluded in an amount linearly proportional to the number of 6-MR paired Al sites, quantified by Co titration. In contrast, CHA zeolites crystallized using mixtures of TMAda and K provide evidence that three K cations, on average, displace one TMAda from occupying a cage and contain predominantly 6-MR isolated Al sites.