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March 2017 www.coalage.com 15 coal-fired power continued The gas is cooled in a separate vessel be- fore the next step. The NETL continued, "The syngas can be cleaned relatively easily, given the much lower volume of raw syngas to be treated compared to the large volume of flue gases that need to be treated in conventional post-combustion cleaning processes." This means most of the sulfur and carbon either remains in the slag or is removed in the wash, occurring in a third vessel. The syngas flows to vessel four where, the NETL reported, "The clean syngas can be combusted in turbines or engines[.]" In the meantime, back up to step one where the heat from the syngas is captured in the form of steam, which then turns a turbine and garners the designation "combined cycle." Simple enough in theory, but in prac- tice, five iterations of the IGCC plant launched stateside and three of those ef- fectively failed as power plants before Mis- sissippi Power's Kemper County Energy Facility reportedly went online in January. Two early prototype IGCC facilities ul- timately closed and were relocated, but in hindsight and for research purposes were "quite successful," said Thomas Sarkus, senior industrial partnerships manager, NETL. The Cool Water, California, plant featuring Texaco gasification technology came online in 1984 and was terminated in 1989. It reincarnated in Kansas as the Coffeyville Resource Nitrogen Fertilizer Plant, where it gasifies petroleum coke in the production of fertilizer. The plant re- portedly currently captures 650,000 met- ric tons per year (mtpy) of carbon dioxide (CO 2 ) for enhanced oil recovery (EOR), a process that uses the gas to extract some of the last remnants of oil from depleted wells. Similarly, a Dow Synfuels Corp.-sub- sidized IGCC plant located in Plaquemine, Louisiana, and featuring Louisiana Gasifi- cation Technology Inc. technology, ran for more than a decade starting in the mid- 1980s. The subsidies expired, the plant closed, and then it effectively reincarnated as the Wabash River facility in West Terre Haute, Indiana. Wabash, which started up in 1995 and gasified 2,500 tons per day of coal and pet coke, had the "hardest row to hoe," Sarkus said. It was the first commercial, mean- ing producing more than 200 megawatts (MW ) per day, IGCC plant in the United States (and the second in the world af- ter Nuon Power's Buggenum plant in the Netherlands). Last May, the Wabash River plant changed hands, no longer produces power, and is currently being retooled to produce fertilizer using pet coke, a transformation described by new owner Phillip Brothers Fertilizer as putting the technology to "a more productive economic use." With- in that quote lies the common denom- inator in the closure of the Cool Water, Plaquemine and Wabash plants. By most accounts, they were shuttered not due to designs on the computation pad, but due to balances on the ledger. They were functional but expensive to operate, and ultimately successfully served as research facilities. Beyond those three, roughly a dozen more have been proposed but were axed by the government sometime be- fore the ribbon-cutting. For example, last March, the California Energy Commission terminated the 300-MW Hydrogen Energy California IGCC plant in Kern County. Worldwide, there have been only eight commercial-scale IGCC plants to suc- cessfully launch since Wabash in 1995: Polk Power Station (USA) in 1996; Vreso- va (Czech Republic) in 1996; Puertollano (Spain) in 1998; IGCC Nakoso ( Japan) in 2007; GreenGen (China) in 2012; Edward- sport (USA) in 2013; Taean (South Korea) in 2016; and Kemper (USA) in 2017. That history perhaps explains why Tampa Electric Co.'s (TECO) Polk County trophy IGCC facility garnered thousands of tourists per year during its first de- cade of operation, Sarkus said. "It is quite a spectacle to see," he said. "They are a crackerjack unit in terms of the chemistry and fine tuning that unit to run." There are other reasons the unit drew gawkers. The facility, referred to as Polk 1, was named by Energy Probe as the clean- est coal-burning power plant in North America in 2005. In 2015, it won the Edi- son Electric Institute (EEI) Edison Award, the institute's foremost accolade, for its system of using reclaimed water in its op- TECO's 250-megawatt (MW) Polk 1 unit flow diagram, above, provides a hint of the challenges faced by engineers in designing a system that creates, then scrubs, then burns, then recaptures the heat from syngas. (Photo: NETL)