Novel sorbents for mercury emissions control from coal-fired power plants

The authors have successfully developed novel efficient and cost-effective sorbents for mercury removal from coal combustion flue gases. These sorbents were evaluated in a fixed-bed system with a typical PRB subbituminous/lignite simulated flue gas, and in an entrained-flow system with air simulating in-flight mercury capture by sorbent injection in the ductwork of coal-fired utility plants. In both systems, one of the novel sorbents showed promising results for Hg(0) removal. In particular, this sorbent demonstrated slightly higher efficiencies in Hg(0) removal than Darco Hg-LH (commercially available brominated activated carbon) at the similar injection rates in the entrained-flow system. The other novel sorbent showed excellent Hg(0) oxidation capability, and may enable coal-fired power plants equipped with wet scrubbers to simultaneously control their mercury and sulfur oxides emissions. In addition, fixed-bed results for this sorbent showed that co-injection of a very small amount (similar to 10%) of raw activated carbon could eliminate almost all of the mercury generated by reactions of Hg(0)) with the sorbent. (c) 2007 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.