Researchers at the Power Systems Development Facility in Wilsonville, Ala., are testing a coal-gasification technology that will "set the foundation for coal as an efficient and environmentally friendly fuel for the future," officials said Monday.
The system uses a transport reactor developed by Kellogg Brown & Root, a Halliburton Co. unit, in conjunction with Southern Co., one of the biggest generators of electricity for the US market and operator of the Wilsonville research facility for the US Department of Energy.
That system has already proven itself to be "the best pressurized, fluidized-bed combustion process in the world" for burning coal to fuel electric generators, said Randall E. Rush, director of the Power Systems facility.
Unlike conventional coal-fueled systems that operate in normal atmospheric conditions, this system is pressurized to help reduce emissions of sulfur dioxide, nitrogen oxides, and particulate matter inside the combustor, so as to eliminate the need for expensive postcombustion controls of those pollutants. Officials also expect it to reduce carbon dioxide emissions by more than a third, compared with conventional coal-fired systems.
The transporter reactor operated some 5,000 hr in that mode, using everything from coke to bituminous coal for fuel before being converted into a coal gasifier to transform coal into a combustible gas.
Although it is still early in its coal-gasification testing cycle, Rush said researchers are "confident" they can achieve a conversion level of 90 btu of energy from 1 cu ft of bituminous coal, with 100 btu "probably" achievable. "Those are the bottom-end numbers," he told OGJ Online.
A ratio of 150 btu/cu ft is the minimum acceptable level, he said.
Southern Co. will decide whether to build a commercial electric power plant using that technology within 24 months or possibly 12, officials said Monday.
Designed to be the nation's test center for evaluating critical components of future coal-fired power systems, the Wilsonville facility is capable of operating at pilot to near-demonstration scales. That means successful projects can move from there into commercial operations more quickly.
Researchers anticipate that this new coal-gasification technology can be applied to both new and existing power plants.
The only commercial US coal-gasification plant is the Great Plains Synfuels Plant in Beulah, ND. A product of the giant government-funded push to develop synthetic fuels under US President Jimmy Carter, the Great Plains plant became a white elephant when natural gas prices fell in the 1980s. Participating energy companies pulled out of that project, leaving the federal government stuck with a bagful of loan guarantees and the scaled-back plant, which it eventually sold for pennies on the investment dollar.
Despite gains made by natural gas in the electric power fuel market in recent years, federal officials report most electric utility plants in this country are still fired by coal. Moreover, the US has more coal resources than Saudi Arabia has oil.
But coal remains the dirtiest of fossil fuels. "Future coal systems will have to become increasingly cleaner and more efficient if the United States wants to use its most abundant and economical fuel to meet energy demands and sustain economic growth. We are pleased to report that we are making huge progress in our clean coal research at the Power Systems Development Facility," said Robert W. Gee, assistant secretary for fossil energy at DOE.
DOE funds 80% of the $275 million Power Systems Development Facility. Other participants include the Electric Power Research Institute, Foster Wheeler Corp., Peabody Group, Combustion Power Corp. and Siemens Westinghouse Power Corp., along with Kellogg Brown & Root and Southern Co.