Maintenance Excellence for 36 Years – And Still Going Strong
Colstrip is known as the “energy capital of Montana.” Established in 1924 when the Northern Pacific Railroad started mining nearby coal to fuel its steam locomotives, Colstrip exists today as a quiet, closely knit community of more than 2,000 citizens and 22 parks situated about 90 miles east of Billings. And it is home to Montana’s largest electricity generating plant and one of the largest remaining coal plants in the country: the 1,480 MW, coal-fired Colstrip Power Plant.
NAES Power Contractors has been the plant’s maintenance and construction contractor since 1988, providing general maintenance, overhauls, and capital project work. Some of these projects have consisted of large component change-outs, while others have involved major environmental upgrade projects, including SmartBurn burner upgrade to reduce NOX emissions and scrubber upgrades to reduce SO2 and particulate emissions.
Currently, the Colstrip plant is in the middle of a significant, planned outage. NPC is providing turnkey services by managing all aspects of the work, including project management, QA/QC, and safety oversight. The scope of work is mostly repair per inspection, with the addition of several larger, known projects.
One component of the work has NPC conducting a major overhaul on one of the plant’s boilers. An extensive undertaking, NPC has provided boilermakers, pipefitters, carpenters, electricians, insulators, and laborers to perform the work, while also subcontracting and overseeing other aspects of work. At its peak, manpower on the project reached 320 union craftsmen.
During the overhaul, 700 waterwall tubes were replaced in a 10-tube/20-foot-long panel configuration. In addition to the waterwall work, other tube work consisted of replacing superheat, reheat, and economizer tubes. In the end, a total of 2,874 tube welds were made with an x-ray rejection rate of only 0.5%.
“NAES has been a solid, valuable partner in Colstrip’s performance over the years. Colstrip continues to deliver reliable, cost-effective power to the Northwest, and NAES has played a key role in Colstrip’s success.”
Neil Dennehy, Colstrip Plant Manager
The larger, previously identified projects consisted of a full burner replacement, coal pipe replacement, hot reheat piping replacement, and air preheater basket and seal replacement. Other areas of work included flue gas, primary air, small valves, snubber turbine support, scrubber duct repairs, lime tank relining, full boiler scaffold, and boiler inspection.
While the final pieces of this outage work are being completed, the project is moving toward completion on time and on budget.
In addition to the boiler work, NPC has recently provided additional mechanical construction services to the site, including construction on multiple onsite water treatment facilities and a Brine Concentrator water treatment facility. The work included rigging and setting major equipment and pumps, fabricating and installing the necessary piping, and providing platforms, structure steel, and plant air and water. In total, NPC performed 3000 welds on ASTM 2205, 6 moly, and ASTM 316 pipes ranging from ½ inch to 40 inches in diameter.
To learn more about NPC’s maintenance, repair, and construction services, contact
Steve Cox
NAES Power Contractors
steve.cox@naes.com
406-748-5535