Project Summary:
Apogee Scientific Inc. will assess up to a dozen carbon-based and other sorbents that are expected to remove more than 90 percent of mercury and cost 40 to 75 percent less than commercial sorbents because they feature inexpensive precursors and simple activation steps. Six to 12 sorbents will undergo fixed-bed adsorption tests with the most promising three to six being further evaluated by injecting them into a pilot-scale electrostatic precipitator and baghouse. Commercial flue gas desulfurization activated carbon will provide the baseline for comparisons. A portable pilot system will be constructed and would accommodate a slipstream ESP or baghouse at minimal cost. Tests will be conducted at Wisconsin Electric's Valley power plant in Milwaukee, WI, and Midwest Generation's Powerton Station in Pekin, IL. The project team consists of URS Radian, Austin, TX; the Electric Power Research Institute, Palo Alto, CA; the Illinois State Geological Survey, Champaign, IL; ADA Environmental Solutions, Littleton, CO; and Physical Sciences Inc., Andover, MA.

Public Abstract:
The US power generation industry relies heavily on coal, burning nearly 1 billion tons per year, to provide the heat and electricity required to maintain America's position as an industrial leader and to provide these services at a reasonable cost to American's homes. Coal contains trace levels of mercury and burning coal has the potential to release this mercury into the atmosphere. In an effort to protect people and the environment while continuing to use coal as a fuel, DOE, EPA and EPRI have been working with industry trade groups and environmentalists to quantify the fate of mercury and to evaluate the costs and benefits of mercury control regulations.

To address critical questions related to cost and efficiency of mercury control technologies, DOE has undertaken an initiative titled "Testing and Evaluation of Promising Mercury Control Technologies for Coal-Based Power Systems" with an portion of the initiative focused on testing novel an less mature control technologies on actual flue gas at the pilot scale. Injection of activated carbon or other sorbents upstream of a particulate control device is one potential method for controlling mercury emissions from utility boilers. Carbon-based and other sorbents have been developed for control of mercury emissions from municipal- and hazardous-waste incinerators. Existing data from the incinerators provide some insight into mercury control, however the costs of using commercially available activated carbon is still fairly high.

Apogee Scientific is submitting this proposal to address the needs identified under Topic 4 of the DOE initiative to test novel and less mature technologies. The proposed program involves evaluating novel sorbents for mercury control at the pilot-scale in actual flue gas. Under the laboratory sorbent development program supported by EPRI, over 1000 potential sorbents have been evaluated and many promising low cost mercury sorbents and processes have been identified. DOE has also supported the development of a novel sorbent by Physical Sciences Inc. (PSI) which will be evaluated during this program. The novel sorbents are projected to cost 40% to 75% less than commercial activated carbons by using inexpensive precursors along with simple activation steps. The sorbents also have the potential for greater than 90% mercury removal. Examples include carbons prepared from coals with high organic sulfur content, biomass, waste tires, fly ash, and zeolites. Some of these potential sorbents were further enhanced by chemical impregnation with materials like sulfur. The non-carbon-based sorbents may also have lower impact on ash use and disposal issues.

The test program includes fixed-bed adsorption tests on 6 to 12 sorbents in the flue gas. This site specific performance data will be evaluated with the physical properties of the sorbent to predict the required injection rate into an ESP and baghouse and the associated costs. The most promising 3 to 6 sorbents will be evaluated by injection into a pilot ESP and baghouse. The baseline sorbent for performance comparison is the commercially available FGD activated carbon.

A portable pilot system fabricated by Apogee for EPRI will be used during this program. This pilot is configurable as a slipstream ESP or baghouse (including EPRI's COHPAC configuration) and can be installed at minimal cost. The fixed-bed and pilot systems are owned by EPRI and will be provided to this program at no cost.

Testing will be conducted at Wisconsin Electric's Valley Power Plant in Milwaukee, WI and at Midwest Generation's [Edison Mission Energy] Powerton Station in Pekin, IL. Valley fires a bituminous coal and Powerton a Powder River Basin coal. Testing at these two plants will provide information on the impact of flue gas composition on sorbent effectiveness.

Apogee has selected a program team consisting of technical leaders in the areas of mercury measurement and mercury control with dry sorbent injection and other technologies. Qualifications of individual team members were built by performing pioneering mercury control work in the U.S. over the past decade. Team members have established many of the technical benchmarks that are accepted by the utility industry today. Organizations represented on the team include URS Radian, EPRI, the Illinois State Geological Survey, ADA Environmental Solutions, and Physical Sciences. The program team understands the work that is expected and has prepared a well thought-out scope of work to accomplish the objectives of DOE.