Wisconsin Power & Light Co.’s largest coal-fired powerplant, Columbia Energy Center, with two subcritical units over 500 MW, was required to bring its air emissions into compliance with federal standards. The utility engaged Black & Veatch to engineer, procure and construct a state-of-the-art air quality control retrofit.
The new equipment included a carbon injection system to reduce mercury emissions, a semi-dry flue gas desulfurization system to reduce sulfur-dioxide emissions and a pulse-jet fabric filter to reduce particulate emissions. Common equipment to support the new emission controls at both units included a reagent preparation system, lime storage silos, scrubber solids handling and conveying system, a truck-based lime delivery station, induced-draft booster fans, air compressors, control system extension and ancillary equipment. The site was arranged to allow for future installation of lime deliveries and scrubber solids removal by rail.
A large hill, hemmed in by the existing plant, a cooling lake, a river with wetlands and a closed and capped ash landfill occupied the only space available for siting the air quality control system. To create a flat site at the same elevation as the existing plant, the contractor excavated the hill and spread the soil over the sealed ash landfill. The additional protective layer was then used for laydown, office trailers and other purposes. Activities on top of the ash landfill were limited to prevent damage to its protective cap.
The contractor’s voluntary partnership with OSHA proactively reduced hazards for the 750 personnel on site, project officials note. As a result, the project logged more than 1.9 million work hours with no lost-time incidents. The equipment on the $595-million project now functions with 99% or better reliability.
Columbia Energy Center Air Quality Control Retrofit
Owner Wisconsin Power and Light Co., a Subsidiary of Alliant Energy
Lead Design Firm Black & Veatch
Contractor Black & Veatch
Subcontractors API Construction Co.; Babcock & Wilcox; BVW Power Constructors; J.P. Cullen and Sons; Jamar Co.