Entergy, EPRI, and ADA-ES Test Mercury Controls under DOE Grant

Business Wire, March 22, 2005

LITTLETON, Colo. -- Entergy's Independence Steam Electric Station (ISES), in partnership with the Electric Power Research Institute (EPRI) and ADA-ES, Inc., has been selected as a site for the U.S. Department of Energy's (DOE) mercury control technology field testing program to test EPRI's TOXECON II(TM), an experimental mercury control technology. TOXECON II(TM) uses sorbent materials that naturally adsorb mercury to remove it from coal plant flue gas. The field test is being conducted as part of a $5.5 million cooperative agreement awarded to ADA-ES by the DOE through its National Energy Technology Laboratory (NETL). The ISES portion of the project is $1.5 million. The DOE/NETL is providing over 70 percent of the funding as part of a research program to advance the technical readiness of mercury control technology options for the nation's fleet of coal-fired power plants.

Under the cooperative agreement, tests will be conducted to evaluate the effectiveness of TOXECON II(TM) in reducing mercury emissions from plants that burn low-sulfur Western or high-sulfur Eastern coals. To date, mercury control technologies have achieved different reduction levels at plants firing these two types of fuels, presumably because of the differences in chemical composition of the fuels. This situation means that tests need to be conducted on the flue gas from both fuels.

The test at ISES Unit 2, an 816-megawatt facility in northeast Arkansas, will begin later this year. Prior to testing, an injection grid will be installed before the last two fields of the electrostatic precipitator on ISES Unit 2. A variety of sorbents - including activated carbon - will then be tested to determine 1) how well each combines with the mercury in the flue gas, and 2) how effectively they are then removed by the last fields of the precipitator.

Each sorbent will be injected into the flue gas downstream of the ESP's initial particulate matter collecting fields. This technique avoids one important problem at facilities like ISES, which recycles over 90 percent of its fly ash into commercial use. Previous activated carbon tests at power plants have injected the carbon in the flue gas upstream of the ESP. This contaminated the fly ash, rendering it unusable for recycling.

By injecting the carbon in the latter part of the ESP, it is possible to capture most of the fly ash upstream of the injection - before it mixes with the carbon. Entergy hopes this technique will allow facilities like ISES to meet two potentially conflicting goals - reduce mercury emissions and continue to recognize the benefits of recycling fly ash. Those benefits include the ability to: 1) maintain revenues from fly ash sales to offset plant operating costs; 2) reduce carbon dioxide emissions in the production of cement; and 3) reduce the need for onsite landfills for fly ash.

Coal-fired electric producers across the country are researching control technologies as they prepare to meet new U.S. Environmental Protection Agency standards for regulating mercury. The new standards will require U.S. coal-fired utilities to reduce overall mercury emissions.

Finding an effective mercury control technology is a complicated matter. Not only are reduction levels influenced by the type of coal burned, but they're also affected by the configuration of the plant, existing emissions controls and operational variables. The energy industry is striving to identify practical solutions that achieve the necessary environmental benefits. The ISES test will help determine if TOXECON II(TM) is a feasible long-term reduction technology for low-sulfur sub-bituminous generating units with a cold-side ESP.

"Entergy is delighted that DOE has chosen the Independence facility as a demonstration site for TOXECON II(TM)," stated Mike Bakewell, Entergy's senior vice president of fossil operations. "Entergy continues to look for technologies and alternatives to lower the cost of controls and ease the impact on its customers, while protecting the environment."

"This project is an important component of NETL's overall program to develop advanced mercury control technologies and to evaluate their performance on actual coal-fired power plant flue gas," said Joseph Strakey, NETL's Office of Coal & Power R&D director. "As such, it directly supports the President's Clear Skies Initiative that calls for a phased-in reduction in mercury emissions."

Strakey added, "It also demonstrates the kind of R&D successes that can be achieved through government partnership with the private sector."

Ramsay Chang, EPRI technical leader for air emission control stated, "TOXECON II(TM) responds to the power industry's needs for mercury control options from which to select the most effective solution for a given power plant, considering the fuel it burns and existing air pollution controls. We are pleased that Entergy and the DOE have chosen to build on earlier EPRI programs at smaller plants to test this new technology on a mainstream power generator."