NOx Control Technology Requirements Under the United States' 1990 Clean Air Act Amendments Compared to Those in Selected Pacific Rim Countries

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5 emission levels. Table 1 summarizes emission standards for eight Pacific Rim countries. More detailed information is given below on emission standards in several of these countries. B. ' Japan As with the U.S. Title I requirements, NOx emission standards are based on available control technologies combined with economic considerations. For the most part, Japanese NO x control requirements are based on combustion modification technologies such as flue gas recirculation, staged combustion (or overfire air), and low NOx burners. There is no di rect requi rement inmost cases for the installation of any particular control technology; however, the emission standards are set such that they can typica lly be met us i ng low NOx burners or other combustion modification technique. For coal-fired plants, NOx emissions are set at 400 ppm (measured at 6% 02), while low NOx burners have been shown capable of emission levels of 150-200 ppm using Japanese low nitrogen coals and 200-280 ppm using imported coals. 8 More stringent control technology requirements may be established under local agreements, and often require the use of a post-combustion control technology such as SNCR or SCR. In one case, the Electric Power Development Company met emission levels of 50-60 ppm using a combination of combustion modification and SCR.8 More common are agreements that lower emission standards to 200-300 ppm, .allowing compliance using combustion modification alone. An overview of Japanese emission standards is presented in Table ~. C. Australia In Australia, the emission limits for NOx are structured similar to the U.S. Title I requirements, with one significant difference. While the U.S. government sets required ambient air quality standards that the states are responsible for meeting, the Australian federal government sets national advisory guide7ines for ambient pollutant levels and emissions. As in the ~.S. Title I, the Australian state and territorial governments are responsible for setting the actual limits for emissions. 9 Table 3 shows both the national guidelines and the mandatory state limits for NOx emissions in two of Australia's states. There is no control technology requirement for meeting these emissions; Australia relies on emissions­based rather than techno logy-based standards. However, the emi s s; ons-based standards are derived from the use of combustion modification control technologies (e.g., low NOx burners).