Selective catalytic reduction for coal-fired power plants: pilot plant results. Final report

Ammonia-based selective catalytic reduction (SCR) has been proposed as a means of reducing NO/sub x/ emissions from coal-fired utility boilers well below current federal standards. EPRI is conducting a technical evaluation of the SCR process on a 5000 scfm pilot-scale facility at the EPRI Arapahoe Test Facility. The pilot-scale system treats a 5000 scfm slipstream of flue gas (2.5 MWe equivalent) from Arapahoe Unit 4 which fires a western low sulfur coal. In addition to the SCR reactor, the system includes a regenerative air heater to assess impacts on air heater performance. The results obtained during a one-year test program are presented. These include (1) the process performance (NO/sub x/ removal), (2) impacts of secondary emissions, including ammonia, SO/sub 3/, and ammonium/sulfate compounds, (3) impacts of increased SO/sub 2/ levels, (4) impacts on the air preheater due to deposit buildup, and (5) evaluation of the SCR process requirements, including the ammonia injection controls, and the performance and maintenance of flue gas monitoring systems. 50 figs., 15 tabs.