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Dry Scrubber Interconnect

Background

Alcan Smelters and Chemicals operates an aluminum smelter in northwest British Columbia. Gases from the smeltering process are treated using eight Dry Scrubbers. During routine maintenance or equipment failure, wet scrubbers were used to take over the gas treatment. These Wet Scrubbers produced an effluent no longer permitted to be discharged into the environment. The solution to the problem was to connect several dry scrubbers together such that two could handle the work of three.

Project Scope

Universal Dynamics provided engineering and construction supervision for Phase 2 of the Dry Scrubber Interconnect Project that consisted of upgrading three dry scrubbers and interconnecting the ducting of six buildings. New fans and material handling equipment was installed to process the increased alumina, and 1,500 feet of duct was installed to connect all gas handling systems. Each existing scrubber was rewired to a PLC so that control would be automated.

Phase 3 of the Dry Scrubber Interconnect Project consisted of upgrading two existing dry scrubbers, interconnecting the ducting of three buildings, installing a new high voltage power supply, and constructing a third complete dry scrubber system. Due to the scope of the project, limited construction time, and limited space, Phase 3 was constructed over two years. Foundations and structural steel were installed in the summer of 1995, ducting, mechanical equipment, and electrical upgrades were installed in the summer of 1996.

Highlights

Universal Dynamics provided detailed design and project management for the Dry Scrubber Interconnect Project. To eliminate effluent discharge of the wet scrubbers, Alcan did not permit any downtime of the scrubbing system; duct tie ins were designed to be easily installed and allowed for variations in the existing ducts. Advanced PLC hardware and custom software allow for all scrubbers to be controlled from a single control room. The new dry scrubber includes new technology for transporting alumina that eliminates high maintenance bucket elevators and airslides.