Thermal desorption characteristics of the adsorbate in activated carbon based on a two-dimensional heat and mass transfer model

Abstract

• A multiphase model of heat and mass transfer in porous media is established. • The multiphase model is validated to simulate the thermal desorption behavior of activated carbon adsorption. • A simplified evaporation rate formula is proposed, and the agreement between the model and the experimental results are verified. • The effect of high thermal conductivity activated carbon on thermal regeneration time is analyzed. • The effects of polar and non-polar adsorbates on model accuracy are analyzed. Thermal desorption of adsorbate in activated carbon is the main part in the thermal regeneration process of spent activated carbon, and previous studies have carried out a series of numerical simulations on it. However, since activated carbon is a porous medium, the heat and mass transfer in activated carbon is different from that in solid. In this paper, a multiphase model of heat and mass transfer in porous media was constructed to study the thermal desorption characteristics of adsorbate in spent activated carbon. In addition, a simplified evaporation rate formula is proposed in this paper, and the agreement between the simulation and the experimental results is verified. When the surroundingtemperature is less than 673.15 K, increasing the surrounding temperature has a significant effect on reducing the thermal desorption time of the adsorbate. Using activated carbon with a thermal conductivity of 5 W / m ∙ K can save about 40% of energy consumption. The model established in this paper can accurately simulate the thermal desorption of adsorbate in activated carbon, which is helpful to deeply understand the mechanism of activated carbon thermal regeneration. In engineering practice, the model can provide technical support for optimizing the thermal regeneration process of spent activated carbon and reducing energy consumption in a targeted manner.