Bench-scale studies of in-duct mercury capture using cupric chloride-impregnated carbons

A brominated activated carbon (Darco Hg-LH) and cupric chloride-impregnated activated carbon (CuCl2-ACs) sorbent have been tested in a bench-scale entrained-flow reactor system which was developed for simulating in-flight mercury capture in ducts upstream of particulate matter control devices. The bench-scale experimental system has been operated with the conditions of a residence time of 0.75 s and a gas temperature of 140 degrees C to simulate typical conditions in the duct of coal-fired exhaust gas. In addition, sorbent deposition on walls which can occur in a laboratory-scale system more than in a full-scale system was significantly reduced so that additional mercury capture by the deposited sorbent was minimized. In the entrained-flow system, CuCl2-ACs demonstrated similar performance in Hg adsorption and better performance in Hg0 oxidation than Darco Hg-LH. In addition, the carbon content of those sorbents was found to determine their Hg adsorption capability in the entrained-flow system. The bench-scale entrained-flow system was able to demonstrate the important Hg adsorption and oxidation characteristics of the tested sorbents.