Comprehensive impact of Lewis/Brönsted acid sites and bed geometry on glucose dehydration

Acidic catalysts with multiple active centers have attracted considerable interest in bioenergy engineering due to their superior catalytic performance enabled by synergistic effects between different active species. The conversion of glucose to 5-hydroxymethylfurfural (HMF) using bifunctional catalysts combining Lewis acid (L acid) and Brönsted acid (B acid) represents a crucial pathway for biofuel production. However, the reaction performance depends on the matching relationships between acid ratio, reaction steps, and transport processes. Here, this dependency was systematically investigated using a mesoscale numerical model based on the lattice Boltzmann method (validated against experimental results) coupled with an acidic sites tunable catalyst model. An empirical relationship between reaction performance and acid ratio was established through regulation of L/B acid distribution in porous catalyst models, revealing an optimal L/B acid ratio of 0.6. By elucidating process coupling mechanisms affecting overall reaction rate under different porosity and bed height conditions, the distinct reactive transport characteristics in different bed regions were identified. Accordingly, an integrated optimization strategy combining acid ratio and bed geometric properties was proposed. The findings emphasize the critical importance of matching catalyst (bed) acid properties, geometry and reactive-transport processes for enhancing overall performance in biomass conversion.