Kinetic modeling is essential in understanding and controlling the process of cellulose hydrolysis for producing value-added cellulose derivatives. This study aims to adopt a set of dominate kinetic ordinary differential equations of cornstalk cellulose hydrolysis in supercritical water for mechanism-based prediction of the production of cellulose, glucose, fructose, glyceraldehyde, erythrose, 5-hydroxymethyl furfural, glycolaldehyde, threose, aldose, and other cellulose derivatives from cornstalks under processing conditions with a pressure of 89 MPa and a temperature of 378 °C, as considered in a recent experimental study in the literature. The yield rates of several cellulose derivatives, e.g., glucose, fructose, 5-HMF, and erythrose as predicted by the present model, are close to those of experimental measurements. The model is further used to predict the yield rates of a few new cellulose derivatives, e.g., glycolaldehyde, threose, and aldose, that are potentially generated in cornstalk cellulose hydrolysis in supercritical water. The present model and computational simulations can be utilized as a rational tool to predict, control, and optimize the derivative yields in cellulose hydrolysis in supercritical water via tuning the process parameters, and, therefore, are useful for the optimal production of targeted bio-based fuels and chemicals from cornstalks and other agricultural and municipal wastes.

Intermediate-temperature (IT) proton-exchange membranes (PEMs) play vital roles in hydrogen and direct liquid fuel cells, electrolyzers, and other electrochemical membrane reactors at elevated temperatures of higher than 150 °C. This article reports the fabrication and performance assessment of a type of new IT polymer–inorganic composite (PIC) PEMs that were made of cerium ultraphosphate (CeP₅O₁₄-CUP) as the durable solid-state proton conductor and undoped polybenzimidazole (PBI) as the high-temperature (HT) polymeric binder. The proton conductivity and electrochemical performance of the PIC PEMs were characterized at 200 °C with varying membrane thickness, processing parameters, and operating conditions using a single-stack hydrogen fuel cell connected to a fuel cell test station. Experimental results show that the PIC membranes (with CUP of 75 wt.%) carried high mechanical flexibility and strength as well as noticeably reduced water uptake of 4.4 wt.% compared to pristine PBI membranes of 14.0 wt.%. Single-stack hydrogen fuel cell tests at 200 °C in a humidified hydrogen and air environment showed that the proton conductivity of the PIC PEMs was measured up to 0.105 S/cm, and the electrochemical performance exhibited its dependence upon the membrane thickness with the power density of up to 191.7 mW/cm². Discussions are made to explore performance dependence and improvement strategies. The present study expects the promising future of the IT-PIC-PEMs for broad applications in high-efficiency electrochemical energy conversion and value-added chemical production at elevated temperatures of 200 °C or higher.

Hydrolysis is essential for converting biomass into biofuels and value-added materials within a sustainable circular economy. However, the high viscosity, non-Newtonian rheology, and high-solids loading of biomass slurries pose significant challenges to reactor design, optimization, and scale-up, making experimental investigations costly and time-consuming. This study employs computational fluid dynamics (CFD) to investigate flow patterns and mixing characteristics in a baffled, mechanically stirred tank designed for high-solids suspensions. A single pitched-blade axial impeller is first validated against published experimental velocity data for a Newtonian fluid using ANSYS Fluent, the multiple-reference-frame (MRF) approach, and the steady Reynolds-averaged Navier–Stokes (RANS) k–ε turbulence model. Several dual-stage impeller configurations are subsequently evaluated under Newtonian conditions to optimize bulk mixing while maintaining realistic tank hydrodynamics. Two identical impellers positioned equidistantly from the tank top, bottom, and each other increase average turbulence intensity by 24% compared with a single impeller in a 100 L tank. Extending the validated model and optimized configuration to non-Newtonian slurry conditions increases turbulence intensity from 8.40% to 10.42%. The results demonstrate that shear-dependent rheology causes flow damping and high-viscosity stagnant zones that cannot be adequately captured using a Newtonian model. Axial positioning of dual-stage impellers emerges as the most influential design parameter for minimizing these zones, with a greater impact than modifying blade size or blade number. These findings provide a foundation for improved biomass slurry mixing and future integration with a thermo-electrocatalytic biomass-to-hydrogen reactor.