The Illinois Environmental Protection Agency is taking comment until Nov. 8 on a draft air construction permit for Ameren Energy Resources Generating Co. and the FutureGen Industrial Alliance for the FutureGen 2.0 project.
This project, backed with U.S. Department of Energy funding help, would be a repowering of part of Ameren’s shut Meredosia power plant. The FutureGen alliance would take over those portions of the plant it needs from Ameren.
The proposed project would be developed to enable the use of carbon capture and sequestration technology, with a portion of CO2 emissions from the plant being captured and sent by pipeline to a sequestration facility. The sequestration facility would be located about 30 miles east of the plant in rural northeastern Morgan County, Ill.
“The project is being developed so that it will not be accompanied by significant net increases in emissions of pollutants that are addressed by the federal rules for Prevention of Significant Deterioration (PSD),” said the Illinois EPA. “In particular, there will be decreases in emissions from permanently shutting down the existing boilers at the Meredosia plant so that the net increases in emissions of PSD pollutants with this project will not be significant.”
As compared to conventional boiler technology, use of oxy-combustion technology will result in a smaller volume of exhaust from the plant with a higher concentration of CO2 in the exhaust. As a consequence, the CO2 from the new plant will be able to be more readily captured than from a conventional steam boiler plant.
This new boiler will replace the existing coal and oil-fired boilers at the source, which will be permanently shut down. This boiler will produce steam that will be used to generate electricity in the existing steam turbine generator at the Meredosia Energy Center that was previously supplied by an oil-fired boiler. Two new cooling towers would be constructed and an existing cooling tower would be rebuilt. A small, oil-fired auxiliary boiler, which will be installed as part of the new plant, would supply steam for the plant for purposes other than generating electricity when the new coal-fired oxy-combustion boiler is not in service.
The new oxy-combustion boiler would be designed for operation with over 95% oxygen. This oxygen would be supplied by an Air Separation Unit that would be built as part of the new plant. The boiler will be designed so that 90% of the CO2 generated during normal operation in oxy-combustion mode would be captured and would not be released to the atmosphere.
This boiler will also have the capability to operate with air, like a conventional boiler. The boiler would start up with air and then transition to the oxy-combustion mode. In the event of an upset in the operation of the boiler or an outage or upset in the CO2pipeline or sequestration facility, the boiler could transition back into air-firing mode.
The boiler will be equipped with a multi-step control train to remove pollutants from the flue gas from the boiler and prepare the gas for processing in the CO2 compression unit. The first step in the system will be a circulating dry scrubber. This device will use hydrated lime to remove SO2 and other acid gases and mercury from the flue gas. The dry scrubber will be followed by a fabric filter or baghouse, which will remove particulate matter, i.e., flyash and entrained lime, from the flue gas. All flue gas from the boiler would pass through these devices to control emissions of the boiler.
In oxy-combustion mode, the flow of flue gas from the fabric filter will be split into two streams. One stream will be recycled back to the boiler, after being supplemented with oxygen from the Air Separation Unit. The other stream will pass through a “polishing system,” with another scrubber and baghouse. The primary purpose of this system is to reduce the moisture content of the flue gas and adjust its temperature for further processing in the Compression Purification Unit. This system will also remove additional SO2 and particulate from the flue gas. The flow of flue gas from the polishing system is again split, with one stream again being recycled back to the boiler. The other stream will go to the Compression Purification Unit to be prepared for sequestration.
The Illinois EPA is also taking public comment until Nov. 8 on a revised water permit needed for the FutureGen 2.0 project. The agency has issued a draft modified National Pollutant Discharge Elimination System (NPDES) permit for discharge into the Illinois River from the Meredosia Energy Center at Meredosia, Ill.
The FutureGen alliance is a non-profit corporation engaged by the Department of Energy (DOE) under a federal financial assistance award to implement the DOE’s FutureGen 2.0 Program. FutureGen 2.0 was initiated in October 2010 by DOE, which has committed more than $1bn in American Recovery and Reinvestment Act (ARRA) funds and other appropriations for research, development and demonstration activities of oxy-combustion and CO2 capture, transportation, and storage.
The project will use a blend of high-sulfur Illinois bituminous coal (60%) and low-sulfur Powder River Basin (PRB) coal (40%) and have a gross output capacity of 176.3 MW, which includes an approximate 8 MW capacity increase that results from a steam turbine upgrade.
Companies involved in the project include The Babcock & Wilcox Co. for the plant itself, Air Liquide for the CO2 part of the project and URS for the balance of plant. The alliance would buy the needed Meredosia assets from Ameren Energy Generating, a unit of Ameren (NYSE: AEE).