A two-stage mathematical model for mercury removal using powdered activated carboninjection upstream of a baghouse filter was developed, with the first stage accounting forremoval in the ductwork and the second stage accounting for additional removal due to theretention of carbon particles on the filter. This model incorporates key mass transfer andequilibrium processes that govern adsorption of mercury vapors on activated carbon in the ductand on the fabric filter. Most of the kinetic parameters were estimated from literature correlationsand manufacturers specifications, while adsorption equilibrium parameters were determined byfitting the model to a set of experimental data obtained from a pilot-scale coal combustor system.Predictive capability of the model was demonstrated using experimental measurements on thesame pilot-scale system. The model shows that removal in the ductwork is minimal, and theadditional carbon detention time from the entrapment of the carbon particles in the fabric filterenhances the mercury removal from the gas phase. A sensitivity analysis on the model showsthat mercury removal is dependent on the isotherm parameters, the carbon pore radius andtortuosity, the carbon to mercury ratio, and the carbon particle radius.
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