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Show for the retrofit market. The goals placed on the NOx subsystem aim for regulations beyond the year 2000. Global markets are being pushed to impose tighter emission regulations, while in the U.S. NOx emissions are currently regulated by Title I and N of the Clean Air Act Amendments. Title I, ozone non-attainment, has NOx limits being set state-by-state. Title I consists of two general requirements: 1) existing major stationary sources must apply reasonably available control technology (RACT) and 2) new or modified major stationary sources must offset their new emissions and must install controls representing the lowest achievable emission rate. The Northeast States for Coordinated Air Use Management (NESCAUM) and the Mid-Atlantic Region Air Management Association (MARAMA) have set an aggressive set of regulations under Title I for NOx emissions for the three different zones in their region. These NO x regulations, shown in Table 1, fall directly within the goals of the LEBS program. Table 1: NOx Reduction Requirements for NESCAUMIMARAMA ~ .< Zone Phase 2 (1999) Phase 3 (2003) Inner 0.2 lbs NO/MBtu 0.15 lbs NO/MBtu Outer 0.2 lbs NO/MB tu 0.15 lbs NO,/MBtu Northern None 0.2 lbs NO/MBtu Source: NESCAUMIMARAMA NO. Budget Model Rule, July 1995. Title IV of the Clean Air Act Amendments sets NOx reduction requirements for Phase I at levels not as stringent as some being set under Title I. Title IV allows utilities to determine the method of compliance that will best suit their needs. These NOx levels can easily be met by currently available 10w-NOx technologies. More stringent limitations are expected to be set for Phase II, which will be determined by January 1, 1997. With these emissions regulations in mind, the Combustion. 2000 program gives the initiative to develop the necessary technologies to meet the future requirements. BURNER DEVELOPMENT To address the objectives of the program, the NOx subsystem developed a combustion system incorporating an advanced pulverizer, 10w-NOx burners, and an advanced overfire air system for the reduction of emissions , without an adverse effect on CO emissions or unburned carbon levels. Through engineering analysis and numerical modeling, an initiallow-NOx concept burner was designed. Pilot-Scale Experimental Testing B&W's Small Boiler Simulator (SBS) was utilized for the initial development of the LEBS advanced 10w-NOx burner. At this scale, extensive testing could be performed more economically. The water-cooled 5 MBtulhr SBS furnace, when operated at its design capacity, has a calculated residence time from the PC burner centerline to the furnace exit of 2 seconds. The inside surface of the SBS furnace is insulated to yield a furnace exit gas temperature of 2100 to 2300oP. The SBS is equipped with an indirect pulverized coal feed system which allows flexibility in adjusting the primary air-to-coal ratio. Primary (coal conveying) air temperatures Page - 4 |