Twenty years ago on page 6 of the January 1988 edition of Power Engineering magazine, a full-age ad introduced “POWER-GEN ‘88” to the world. The inaugural event, which grew to become POWER-GEN International, was held at the Orlando Convention Center from December 6-8. The event covered fossil and solid fuel power generation, including coal, oil, natural gas, municipal solid waste and other waste fuels. “Paper abstracts are invited,” the ad read. That opened the floodgates, which, over the next 20 years, would see thousands of papers researched, written and presented at the world’s largest and most prestigious exhibition and conference for the power generation industry.
Power Engineering magazine has been PGI’s flagship media sponsor since the beginning 20 years ago. This year to celebrate PGI’s 20th anniversary we’ll take a look back at some of the issues and events that were making news. A lot of the same issues continue to make news today.
Emissions control systems were not always an integral part of many power plants’ operations. The August 1988 issue of Power Engineering included a feature story by Ed Cichanowicz, an air quality control program manager with EPRI, that reviewed European experiences with selective catalytic reduction (SCR) controls. The article said that beginning in 1981, EPRI had begun conducting pilot tests to characterize and assess SCR’s potential for use in the United States on low-sulfur coal. As of mid-1988, planning was underway to test SCR on high-sulfur coal. The article said that EPRI had begun two other studies: one to update an SCR economic engineering assessment and a second to evaluate the status, performance and cost of combined NOX/SO2 control systems as alternatives to flue gas desulphurization (FGD) and SCR.
“Although the effects of SCR on plant operation are not clear, the process has shown NOX removal potential up to 90 percent, and is the furthest developed option for achieving very low NOX emissions.” The article said that eight West German and Austrian SCR installations, totaling 2,200 MW, were operating in March 1987. By 1992, SCR capacity across all of Western Europe was expected to reach 26,000 MW. Japan had SCR on 8,000 MW of coal-fired and 28,000 MW of oil-fired capacity.
In the United States, the article said, power plants had been able to show that furnace modifications to inhibit NOX formation were a more cost-effective approach. “They provide significant NOX removal at a much lower cost than SCR.” Combustion modification techniques include operational modifications, such as low excess air, biased firing, and burners-out-of-service, to achieve 20 to 30 percent NOX removal. Low-NOX burners, overfire air, and reburning were shown achieving 40 to 60 percent removal, the article said.
Because fuels used in Europe are similar to U.S. low-sulfur fuels, selected aspects of the European experience were thought to be be directly applicable, the article said. It cautioned, however, that different trace fuel constituents in the U.S. might prevent a direct transfer of experience to domestic low-sulfur, coal-fired power plants. For medium- to high-sulfur coals, the potential existed for accelerated catalyst deactivation caused by sulfur poisoning and contamination by trace metals in the flyash. The potential also existed for accelerated buildup and corrosion of air heaters.
“As a result,” the 1988 article said, “it is not yet certain that the European experience can be applied to the majority of U.S. units that are considered targets for any acid deposition legislation.”
Research efforts were soon to turn to tests on medium- to high-sulfur coals, which were burned by most utilities likely to be affected by 1988-vntage control legislation. Pilot plant facility design was expected to be completed in the summer of 1988, with testing set to begin early in 1989. Catalyst performance tests were to be conducted on up to six pilot plants of 1.2 MW capacity, located at various power plants nationwide. An additional one or two 3 MW capacity pilot plants were to include regenerative air heaters and other environmental control equipment. These would evaluate the effect of residual NH3 and by-product SO3 on downstream processes.
“Critical issues to be resolved in these tests for a range of domestic fuel types include catalyst lifetimes, the impact on overall power plant operation (air heater, FGD, liquid- and solid-waste management), process control and catalyst replacement strategies.”
The article concluded that the scope and direction of future SCR research would depend on how SCR compared with these combined NOX/SO2 processes, as well as on regulatory expectations.
The rest, as the saying goes, is history.