Publications by Wingra Engineering Staff

 

"Evaluating Local Impacts of a Utility SCR Retrofit Project"

Steven Klafka, P.E.
Wingra Engineering, S.C.

ABSTRACT

In response to anticipated nitrogen oxide (NOx) emission control requirements, a Wisconsin utility proposed the installation of a selective catalytic reduction (SCR) control system at its largest power plant. This SCR control system would use anhydrous ammonia as the reagent. The surrounding municipality was given the opportunity to review the project prior to issuing a conditional use permit.  While the SCR project would result in significant reductions in NOx emissions from the power plant, the surrounding community would experience several undesirable effects.  These include generation of ammonia emissions from SCR slip and risks to large populations due to accidental releases during ammonia delivery, handling and storage.  The Village evaluated the project and requested consideration of alternatives to the anhydrous ammonia SCR system which would pose fewer hazards, including the use of aqueous ammonia as a reagent.  SCR systems using anhydrous and aqueous reagents were compared to determine the effects on project costs and the population impacted by accidental releases.  During utility evaluation of these comments, the September 11, 2001 terrorist attacks in New York and Washington, D.C. occurred, increasing awareness of the public security hazards posed by the storage of hazardous materials.  The final SCR design was changed to incorporate the use of the less hazardous aqueous ammonia as the reagent.