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Working closely with EPRI, Alstom Power is responsible for the design, construction and operation of the $10 million pilot plant, which engineers hope will be able to extract 90% of the CO₂ from 1% of the flue gas produced by of the plant's two 617MW coal-fired units. The goal of the project is to capture about 15,000 tons of CO₂ per year.

Lambert Engineers provided engineering project management, process engineering, structural engineering, electrical engineering, instrumentation engineering, and mechanical engineering services.

"The first step is to cool and clean the flue gas, which typically is at 120F to 140F, is water-saturated, and contains residual amounts of SO₂, NO_X, HCL, and particulate matter. Both steps can be accomplished by injected refrigerated water directly into the gas stream. As the gas is cooled, much of its water content condenses out, carrying the residual contaminants with it. The water is then evaporated in cooling towers, substantially reducing the total flue gas volume. The cooled flue gas leaves as a chilly (35F) and dry (<1% moisture) gaseous substance.

"The second process step is CO₂ absorption, which is similar to the SO₂ absorption common at many coal-fired plants today. After the 35F flue gas enters the bottom of the absorber vessel, it is forced upward against the current of a slurry containing a dissolved and suspended mix of lean ammonium carbonate (AC) and rich ammonium bicarbonate (ABC). Chemical reactions remove over 90% of the CO₂ in the flue gas, leaving it only with nitrogen, excess oxygen, and low concentrations of CO₂. Any residual ammonia is captured by a cold-water wash and returned to the absorber.

"The third step of the process takes the CO₂-rich slurry at 1,200 to 1,500 psi (anticipated for commercial use or for transportation to an enhanced oil recovery process or sequestration) from the ABC-rich output of the high-pressure pump and directs it to a heat exchanger. The heat exchanger dissolves the slurry into a clear solution at about 175F and sends it on to the high-pressure regenerator, where additional heat is added by a reboiler to strip away the CO₂ gas. The only by-product of the entire process is a small amount of water; it can either be treated by the plant's wastewater system or recycled and reused."¹

¹ Peltier, Dr. Robert. "Alstom's chilled ammonia CO₂-capture process advances toward commercialization." Power Feb. 2008: 38-41.