(132b) Novel Sorbents for Mercury Capture from Fuel Gas
AIChE Spring Meeting and Global Congress on Process Safety
2006 Spring Meeting & 2nd Global Congress on Process Safety
Combustion - Nox and Sox Control and Modeling
Tuesday, April 25, 2006 - 2:00pm to 2:30pm
There are increasing concerns over mercury pollution in the environment. Mercury is a powerful neurotoxin, and can bio-accumulate up the food chain. The United States Environmental Protection Agency (USEPA) announced on December 14, 2000 its intention to regulate coal-utilizing (gasifiers and combustors) facilities for mercury emissions. The USEPA issued the regulation in March 2005. With EPA's Clean Air Mercury Rule, and several states promulgating their own regulations, the need exists for a low cost mercury removal technique that can be applied to integrated gasification combined cycle (IGCC) and coal-burning power plants. Gasification is an important strategy for increasing the utilization of abundant domestic coal reserves. The Department of Energy envisions increased use of gasification in the United States during the next twenty years. As such, the DOE Gasification Technologies Program will strive to approach a near-zero emissions goal with respect to pollutants such as mercury. In gasification for power generation, the removal of mercury by sorbents at elevated temperatures preserves the high thermal efficiency of the integrated gasification combined cycle system. Unfortunately, most sorbents will 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 for many sorbents for elemental mercury from nitrogen, as well as from four different simulated fuel gases at temperatures from 400F - 700F, were determined. The simulated fuel gas compositions contain varying concentrations of carbon monoxide, hydrogen, carbon dioxide, moisture, and hydrogen sulfide. Promising high temperature sorbents have been identified. Future directions for mercury sorbent development for fuel gas application will be discussed.