Graycor Industrial

Otter Tail Power’s Big Stone Plant AQCS Project Continues to Make Progress

Construction progress on Big Stone Plant’s air-quality control system (AQCS) surpassed the 75% mark in late October. With total labor hours now exceeding 1,294,000, the overall project’s OSHA Recordable Incident Rate is 0.46, a tribute to the emphasis placed on safety by Big Stone Plant’s owners and Graycor Industrial Constructors, the project’s general contractor.

The project achieved significant milestones in erecting the last steel and ductwork sections on the SCR and is targeting substantial completion of the baghouse erection in November. Focus continues on the mechanical, electrical and insulation installation efforts to achieve the remaining construction turnover packages as well as to set out the remaining ductwork from the boiler building to the baghouse and from the ID fans to stack in preparation for the tie-in outage starting in March.

Just as it is managing AQCS construction, Otter Tail Power Company also is performing the commissioning effort. Commissioning involves taking possession of the AQCS equipment from construction, reviewing the systems for conformance, preparing all equipment for operation, starting up all AQCS equipment, facilitating training for plant employees, and formally turning over the AQCS equipment to Big Stone Plant operations. AQCS Commissioning Manager Kirk Phinney and his team were fully mobilized to the AQCS site in September. “My team consists of four contract employees and four Big Stone Plant employees who have transferred to the commissioning effort. Graycor will provide additional craft support,” says Phinney.

The AQCS system currently is divided into 130 construction turnover packages. “Construction already has turned over forty-two of those packages,” said Phinney. Included is the operator interface to the distributed control system (DCS).

With the early effort put into commissioning planning, continued support from engineering, and the team that has been put into place, the commissioning effort has gotten off to a great start,” says Phinney. Construction turnover activity is scheduled to be at its highest rate in January and February, and commissioning activities will carry through Big Stone Plant’s planned major outage in 2015.

“We have been pleased with our safety performance and progress to date on this large, sophisticated project,” says Robert Fritsche, Vice President at Graycor Industrial Constructors. “The Otter Tail team has been great to work with, and their cooperative approach has helped keep the project on track.”

The Big Stone Plant (located in northeast South Dakota, near the Minnesota border) is managed by Otter Tail Power Company, and is owned by Otter Tail Power, Montana-Dakota Utilities Co., and NorthWestern Energy.