TOXECON II AND HIGH-TEMPERATURE REAGENTS OR SORBENTS FOR LOW-COST MERCURY REMOVAL

摘要

On March 15, 2005, EPA issued the Clean Air Mercury Rule, requiring phased-in reductions of mercury emissions from electric power generators. ADA-ES, Inc., with support from DOE/NETL and industry partners, is conducting evaluations of EPRI's TOXECON II process and of high-temperature reagents or sorbents to determine the capabilities of sorbent/reagent injection, including activated carbon, for mercury control on different coals and air emissions control equipment configurations. The TOXECON II technology injects sorbents in the latter fields of an electrostatic precipitator to achieve emissions reduction, allowing recovery and sale of the ash from the first fields since only the last fields are collecting an ash/reagent/sorbent mixture. Injecting non-carbon-based reagents or sorbents in a high-temperature flue gas zone allows a low-cost approach for moderate levels of mercury removal at plants equipped with hot-side electrostatic precipitators. This paper presents an outline of the overall testing program, a description of the TOXECON II installation and testing at Entergy's Independence Steam Electric Station (ISES) in Newark, Arkansas, and a description of the testing program for testing of high-temperature reagents at MidAmerican Energy Company's Louisa Station in Muscatine, Iowa. Entergy's Independence Station burns PRB coal and employs high-SCA cold-side electrostatic precipitators for particulate emissions control. This part of the testing program consists of installing injection grids between the latter precipitator fields and injecting powdered activated carbon into the flue gas stream inside of the precipitator and measuring the resulting mercury removal. MidAmerican's Louisa Station burns PRB coal and employs hot-side electrostatic precipitators with flue gas conditioning for particulate control. This part of the testing program consists of using the existing flue gas conditioning system to inject non-carbon-based reagents upstream of the ESP and measuring the resulting mercury removal. The field testing efforts at both Independence and Louisa are complete and the data analysis for both sites is in progress at the writing of this paper. This paper contains some preliminary findings, and the conference presentation will include any additional available results.