Gas-Solid flow and mass transfer characteristics in activated carbon adsorption equipment: The impact of structural outline

Abstract

The efficacy of adsorption of volatile organic compounds (VOCs) in industrial emissions by activated carbon (AC) is influenced by adsorption kinetics and hydrodynamics. To simulate the performance of continuous flow AC adsorption process, a computational fluid dynamics (CFD) model that includes both multiphase flow and adsorption kinetics was developed. Because of its well-understood adsorption mechanism, N-butane was chosen as the target contaminant in this investigation. Simulation results revealed that velocity distribution uniformity is deeply affected by structural outline. According to simulations of the heat and mass transfer process, the adsorption reaction stoichiometric constraints between n-butane and AC were achieved; however, full utilization of AC was difficult to reach because of the hindered heat accumulation and mass transfer diffusion. Different structural outline leads to a 2.15 % improvement of adsorption efficiency due to an enhancement in the velocity distribution uniformity. The CFD model adequately describes the breakage curve occurring in the gas-solid multiphase flow system and confirms that heat and mass transfer is the rate limiting step in contaminant adsorption. This article investigates the effects of velocity distribution, heat and mass transfer on adsorption efficiency in equipment with different structural outline, and provide valuable insights into the design and application of equipment for eliminating VOCs.