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Show 8 A16SE738.T maintain system frequency and control power flow across ties, the transmission linkages between control areas. Of the two types of adjustments, area regulation has the biggest impact on NOx emissions and control because of the shorter time frame of the adjustment. SNCR Technology Description Selective Non-Catalytic Reduction of NOx (SNCR) is a class of NOx control processes developed to control NOx emissions from fossil fuel combustion systems. SNCR processes involve the injection of a nitrogen-containing chemical into the combustion gases where the temperature is in the range of 1600-2100°F. In this temperature range, the chemical reacts selectively with NO in the presence of oxygen, forming primarily N2 and H20. Ammonia and urea injection have been most widely used for full-scale applications. EPRI patented the use of urea as a reagent for SNCR in 1980. Urea has two main advantages over ammonia. One, it is easier to handle compared to ammonia, a potentially explosive and hazardous chemical when in concentrated form. And two, urea has a temperature window that is slightly higher than ammonia, making it more compatible with higher temperature utility boilers. NOx reduction is expected to be comparable. Nalco Fuel Tech (NFf) has advanced the basic urea technology for application to commercial installations by developing chemical, mechanical and electrical control systems strategies to increase applicability of the process. NFT's licensing agreement with EPRI, combined with its own in-house development efforts have led to a commercially viable NOx reduction process marketed under the trade name NOxOUT. Figure 4 shows an overall schematic of SNCR applied to Unit 1 at B.L. England Station. Prior to this demonstration, Nalco Fuel Tech (NFf) and their licensee, RJM Corporation (RJM), worked with Atlantic Electric to determine if this technology could be applied to a cyclone-rued boiler. Pre-test modeling was done by NFT of fluid dynamic parameters including temperature, and of reaction kinetics. The results of this modeling were used to design a shortterm conceptual test with the intent of validating the model and determining conceptual feasibility of NFT's NOxOUT process. This earlier work was the basis for proceeding with the longerterm demonstration. SNCR INJECTION SYSTEM: A temporary SNCR injection system, similar to that used during the short-term conceptual test, was designed and installed by RJM Corporation adjacent to Unit 1 for the long term demonstration. The system consisted of a temporary storage tank, Nalco Fuel Tech pumping/metering control trailer, injector distribution modules and air-atomized injectors. The injector distribution modules were located on the 6.5 and 8th floor elevations and controlled the atomizing air and chemical flow rate to the individual injectors. A total of 17 injectors were installed on the unit through a combination of new and existing observation ports. These injection ports were the same as those used in the short-term test and were installed based upon temperature measurements and the Nalco Fuel Tech CFD and CKM Model recommendations. Figure 4 is a diagram of the NOxO~ Process installed on Unit 1. |
