Grantee Research Project Results

TDA Research, Inc. (TDA) has developed a novel non-carbon sorbent to control mercury emissions from the flue gases produced by hazardous waste incinerators and coal-fired power plants.  The sorbent could be easily injected into the flue gas and could be recovered in the Particulate Control Device (PCD) along with the fly ash.  Unlike the carbon materials used to date, our sorbent does not alter the properties of the by-product fly ash and render it unsuitable as a cement additive.  In the Phase I project, we demonstrated the technical feasibility of using the non-carbon sorbent for mercury removal at the bench-scale.  The sorbent achieved a much higher mercury capacity than Darco Hg sorbent (a carbon produced by Norit Americas), a benchmark sorbent in mercury emission control from the flue gases, removing over 688 mg/g at 150^oC (302^oF) at 95% Hg removal efficiency in a fixed-bed experimental setup under representative simulated flue gas.  Our sorbent could effectively remove elemental mercury at temperatures as low as 220^oC (428^oF) under simulated conditions.  A 5:1 combination of TDA Hg sorbent with commercial carbon achieved a capacity of 2910 mg/g at 99% removal efficiency. TDA’s Hg sorbent in combination with silica achieved a very high Hg capacity of 6,941 mg/g at 180^oC at 90% removal efficiency. The high temperature operation capability of the sorbent allows its use on the hot-side of an electrostatic precipitator (ESP).  In Phase II, we optimized the sorbent formulation and scale-up its production.  In collaboration with Apogee Scientific, Inc. (Apogee) we demonstrated the effectiveness of our sorbent using a slipstream of actual flue gas at Xcel Energy’s Pawnee Power Station. 

 

This technology may find immediate use for mercury abatement in hazardous waste incinerators.  In addition, the same technology would be applicable to the much smaller application of mercury abatement in municipal waste incinerators and waste-to-energy facilities.  These facilities are becoming more prevalent in the U.S., and are particularly common in Europe, where trouble-prone packed beds of carbon are currently used. The sorbents developed here will also find use in mercury removal from coal fired power plants.