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Major Boiler Overhaul Projects

Day & Zimmermann (D&Z) worked its first contract with this client, and D&Z was the first contractor in 12 years to complete an outage on time at this facility. The scope of services included project management; supervision, including safety, QA, and sub-contractors; planning and scheduling; engineering services; open shop craft labor; supply of tools and equipment. The scope of work included repair and replacement of the following items.

  • Weld repairs and installation of new diaphragm seals in the air preheater.
  • Tilting tangential burner nozzles.
  • Horizontal supply header and waterwall tubes.
  • Main steam safety valve nozzle.
  • Slag screens and support steel in the backpass.
  • Existing turning vanes in the APH inlet and outlet ductwork.
  • Existing W8 beam seats at the sidewall attachments.
  • 43 waterwall tubes and performed numerous pad welds.
  • 156 back pass hanger tubes.
  • 16 division panels and repaired numerous expansion clips.
  • Superheater pendant platens-replaced 10 tubes and performed pad welding for erosion protection and replaced numerous expansion clips.
  • 98 final superheater tubes and numerous expansion clips.
  • 168 low temperature superheater tubes.
  • 12 economizer tubes and numerous expansion clips.

Accomplishments and Innovations

D &Z exceeded this client's expectations when it completed its first outage on-time, and within budget, and with zero recordable injuries. The remote location, high elevation, and the harsh weather presented challenges in both staffing and materials management. The power station is located in a remote area. The team faced record amounts of snow fall with 70-mile-per-hour winds and lower than average temperatures ranging in the low teens to mid-twenties.