MERCURY REMOVAL 6. Schematic of the pilot test facility at Southern Company's Mercury Research Center. Source: Hitachi Power Systems America Ltd. AH Boiler 7. The arrangement of the two layers of catalyst installed during pilot testing at Southern Company's Mercury Research Center. The catalyst volume was 6.7 m3. Source: Hitachi Power Systems America Ltd. SCR AH EP FF Fan 14m 8. Mercury oxidation activity of the catalyst versus halogen concentration. Source: Hitachi Power Systems America Ltd. 1.2 1.0 0.8 0.6 0.4 0.2 0.0 TRAC Conventional Temp. 370 C Br:0 ppm 100 200 CI (ppm) 9. Mercury oxidation activity of the catalyst versus flue gas temperature. Source: Hitachi Power Systems America Ltd. 300 400 full-scale catalyst modules. The flue gas velocities and temperatures were fully controlled during testing. Table 2 shows the mercury oxidation test conditions, and Figure 7 illustrates the outline of the SSR. At this test facility, Hitachi was also able to confirm the performance differences between its typical conventional SCR catalyst and TRAC under actual flue gas conditions. Figures 8 and 9 show mercury oxidation 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 320 activity for both conventional SCR catalyst and TRAC against halogen concentration and flue gas temperature. As can be seen in both figures, TRAC has excellent mercury oxidation performance at both lower halogen concentration and high flue gas temperature zones compared with conventional catalysts. The results illustrate the superior performance of TRAC under all tested operating conditions. TRAC Conventional Full-Scale Commercial Application The first commercial application of TRAC involved adding a full layer of catalysts to a full-scale replacement reactor at the same PRB-fired plant where pilot testing had been conducted earlier. The three-layer replacement reactor conBr:5 ppm CI: 125-150 ppm 340 360 380 Temperature (C) 72 400 420 sisted of three layers with a spare, empty fourth layer. For testing, the first layer of existing honeycomb catalyst was removed and a layer of TRAC catalyst was installed as the fourth layer. Table 3 shows the coal and flue gas analysis data during testing. The TRAC catalyst was supplied and installed in the reactor, and the operation started in June 2008. Hg speciation profiles at the wet FGD inlet and outlet (stack inlet) locations were recorded by using www.powermag.com POWER | October 2011 Relative activity ratio Relative activity ratiohttp://www.powermag.com