At two of its power plants—one in North Dakota and the other in South Dakota—Otter Tail Power enlisted Barr to support the conversion and retrofit of its bottom-ash and economizer-ash conveying from wet to dry systems. The bottom-ash retrofit consists of demolishing existing slag tanks, crushers, sluice pumps, and piping and then installing a submerged drag-chain conveyor under the cyclone-fired boiler. The economizer-ash retrofit involves replacing the ash-holding tanks and sluice piping with drag-chain conveyors and chutes.
Barr provided engineering services for the conversion effort in phases. In the first phase, we conducted three-dimensional scans, developed three-dimensional computer models of the areas slated for new equipment, performed preliminary engineering to establish the design basis, and developed equipment procurement specifications. The second phase involved detailed design of the mechanical, structural, and electrical auxiliaries and site civil layout including construction specifications. The third phase entailed construction support consisting of reviewing shop drawings, responding to owner and contractor questions, and assisting Otter Tail Power in implementing a successful project.