Control of mercury emissions from various combustion sources has attracted great attention due to the toxic nature of mercury and the current and potential regulations. The proposed Clear Skies Act of 2003, introduced in the US House of Representatives as House bill HR 999 and the US Senate as Senate bill S. 485 on February 27, 2003, would create a mandatory program that would dramatically reduce power plant emissions Of SO2, NOx and Hg by setting a national cap on each pollutant. In this study, a process model was developed to simulate mercury sorption by activated carbon in three distinct beds, namely a confined bed, a semi-fluidized bed, and a fluidized bed. The simulation results have suggested that the confined bed has the best mercury control performance; however, it generates the highest pressure-drop across the bed. A semi-fluidized bed offers acceptable performance with affordable pressure-drops and can be a practical candidate for the process.