Modelling of Hg0 removal from gaseous streams and its fixation in hydroxyapatite-based adsorbents modified with copper sulphide

Abstract

In this work, a mathematical model of a fixed-bed process for elemental mercury removal from gaseous streams is proposed. Advective and diffusive processes were taken into account in the macroscopic mass balance along the bed, and diffusive process was considered in the microscopic mass balance inside the adsorbent particle in which the adsorption process occurs. In addition, a chemical reaction term was used to represent the mercury fixation by the adsorbent. The proposed model was implemented in the Environment for Modelling, Simulation and Optimization dynamic simulator. Model parameters were estimated based on experimental breakthrough curves, by minimizing the least-square function. The model satisfactorily described two experimental breakthrough curves of mercury removal using adsorbents with different preparation methods, both with high mercury fixation capacity. The proposed mathematical model was also able to consistently describe the mercury concentrations in the bed and in the particle.