Capturing the effects of particle heterogeneity on adsorption in a fixed bed

To efficiently design new adsorption systems, industrial scale fixed beds are often scaled down to bench-top experiments and/or modeled using computational fluid dynamics (CFD). While there has been considerable work exploring adsorption of volatile organics onto activated carbon fixed beds in the literature, this article attempts to reckon with the high variability of adsorption capacities observed at small scales and improve small-scale experiments for industrial scale reactor design. This study integrates experimental results with CFD simulations, which can explicitly model system heterogeneities and their influence on adsorption by resolving local packing densities and flow paths. Activated carbon physical properties were determined through surface area analysis, proximate analysis, and toluene adsorption (measured via mass spectroscopy). Variability in the small-scale systems was not attributed to surface area or carbon content, as is often stated, but instead was due to local packing density variations and the heterogeneity of particle size distributions.