Sorbents for mercury capture from fuel gas with application to gasification systems

In regard to gasification for power generation, the removal of mercury by sorbents at elevated temperatures preserves the higher thermal efficiency of the integrated gasification combined cycle system. Unfortunately, most sorbents display poor capacity for elemental mercury at elevated temperatures. Previous experience with sorbents in flue gas has allowed for judicious selection of potential high-temperature candidate sorbents. The capacities of many sorbents for elemental mercury from nitrogen, as well as from four different simulated fuel gases at temperatures of 204-371 degrees C, have been determined. The simulated fuel gas compositions contain varying concentrations of carbon monoxide, hydrogen, carbon dioxide, moisture, and hydrogen sulfide. Promising high-temperature sorbent candidates have been identified. Palladium sorbents seem to be the most promising for high-temperature capture of mercury and other trace elements from fuel gases. A collaborative research and development agreement has been initiated between the Department of Energy's National Energy Technology Laboratory (NETL) and Johnson Matthey for optimization of the sorbents for trace element capture from high-temperature fuel gas. Future directions for mercury sorbent development for fuel gas application will be discussed.