Mechanism of Using Activated Carbon for Mercury Removal in Flue Gas

A bench-scale experimental system was conducted to study properties of activated carbon adsorption for mercury removal in flue gas. The test method used here for mercury concentration was cold-vapor atomic fluorescence spectroscopy (CVAAS). Mercury breakthrough efficiencies of activated carbon in different simulated flue gas systems were studied in typical constituent flue gas system. The conclusions are as follows: Mercury breakthrough efficiencies will become higher with adsorption temperature becoming higher; Mercury breakthrough efficiencies will become lower with C/Hg becoming higher; In order to make small dosage and cost-effective mercury adsorbents, two modified activated carbons were prepared by chemical methods including activated carbon impregnated with activated MnO₂, and activated carbon impregnated with FeCl₃. After analyzing the adsorbent mechanism of activated carbon and modified activated carbons, it is believed that there is chemical adsorption other than physical adsorption during the adsorption process of modified activated carbons.