文献类型：期刊文献

英文题名：CFD simulation of mass transfer in adsorption column: Numerical analysis of molecular diffusion and convection

作者：Li, Xue[1];Wu, Yan-Yang[1];Peng, Yang-Feng[1];Wu, Bin[1];Chen, Kui[1];Ji, Li-Jun[1]

机构：[1]East China Univ Sci & Technol, Sch Chem Engn, Shanghai 200237, Peoples R China

年份：2025

卷号：79

外文期刊名：JOURNAL OF WATER PROCESS ENGINEERING

收录：;WOS:【SCI-EXPANDED(收录号:WOS:001609644900003)】；

语种：英文

外文关键词：Adsorption; Molecular diffusion; Convection; Simulation

摘要：Adsorption is widely employed to remove Ca2+ from hard-water; however, inadequate mass transfer compromises separation performance. Accordingly, it is essential to elucidate mass transfer mechanisms for process optimization. This study investigates mass transfer in adsorption column for hard-water softening via computational fluid dynamics (CFD) simulation. Among four models, a molecular diffusion-convection-dispersion model best reproduces adsorption behavior. Breakthrough curves are calculated under different linear velocity, feeding concentration, height-to-diameter (H/D) ratio, and temperature. Afterwards, concentration distribution in mass transfer zone (MTZ) is visualized by CFD-POST; its expansion rate exhibits an exponential decay. Meanwhile, the influence of molecular diffusion on mass transfer is quantified via the relation between effective diffusion coefficient (De) and effluent concentration at different temperature, porosity, and tortuosity. Effluent concentration increases by 3.44 % as porosity rises from 0.35 to 0.50 (attributed to increasing De) while decreases by 96.83 % when temperature increases from 298.15 to 323.15 K (due to combined effects of kinetic and thermodynamics). Additionally, the effect of convective mass transfer coefficient (kc) on mass transfer is evaluated by mass transfer height (hMTZ) and times to C5%, C50%, and C95% breakthrough. Higher kc increases hMTZ and triggers a radial-to-axial transition in MTZ expansion at maximum hMTZ. Moreover, increasing kcvia linear velocity shortens C5%, C50%, and C95% times by 95.7 %, 92.2 %, and 91.4 %, respectively; times also change under other operating conditions even when kc is nearly unchanged. Results indicate mass transfer co-influenced by convection and molecular diffusion. This work provides theoretical basis for adsorption mass transfer and industrial hard-water softening.