Following a plant-wide power outage, a pulp and paper facility experienced abnormal steam turbine operation during startup. Operators identified a significant discrepancy between the upper and lower valve rack positions, indicating an issue within the turbine steam admission system that required immediate investigation.

With the facility’s regular service provider unavailable, Blackstone redirected a nearby field service crew to respond. After troubleshooting all accessible external components, the team determined that the issue originated within the turbine and that further disassembly would be required.

Inspection revealed that a valve seat had experienced weld failure and shifted out of position, preventing proper valve operation and restricting steam flow to the turbine nozzle. With no spare components available onsite or through the OEM, Blackstone mobilized field machining and welding specialists while simultaneously developing a replacement solution.

Using measurements obtained from the damaged component, Blackstone successfully re-engineered and manufactured two replacement valve seats within four days, providing both an immediate repair solution and a spare component for future reliability.

Damaged valve seats removed for re-engineering

• Troubleshoot turbine valve rack discrepancies following an unplanned outage
• Remove and inspect damaged valve seat assembly
• Perform field machining, welding, and installation activities
• Re-engineer and manufacture replacement valve seats
• Support turbine lid removal and reassembly operations
• Conduct internal inspections and debris recovery activities

Several critical challenges required immediate action to restore the unit safely:

• No replacement valve seats were available onsite or through the OEM
• Emergency field machining and welding activities were required under outage conditions
• Replacement components had to be reverse engineered and manufactured without existing drawings
• Multiple specialty services, including induction bolt heating, required coordination under accelerated timelines
• A missing section of the failed valve seat could not initially be located and posed a significant risk to turbine integrity

During the investigation, it was discovered that a portion of the failed valve seat was missing. Extensive borescope inspections were unable to locate the metal fragment, creating concern that it could enter the steam path and cause severe damage to the rotor and stationary components.

To eliminate this risk, the facility elected to remove the turbine lid for a full internal inspection. Following round-the-clock support from a specialized induction bolt heating contractor, the lid was safely removed and the missing fragment was located behind a nozzle assembly. Recovering the debris eliminated the risk of secondary turbine damage and prevented the potential for a significantly longer outage.

The project delivered several critical outcomes:

• Rapid emergency response minimized extended downtime
• Root cause of the turbine issue was quickly identified and corrected
• Two replacement valve seats were re-engineered and manufactured within four days
• Potential catastrophic rotor damage was avoided through proactive inspection and debris recovery
• An additional spare valve seat was provided to improve future outage preparedness
• Multiple specialty services were coordinated through a single point of accountability
• Long-term operational reliability and risk management were improved

Blackstone’s ability to rapidly mobilize field service personnel, coordinate specialized support resources, and manufacture critical replacement components under emergency conditions enabled the facility to safely return the turbine to operation.

Beyond restoring turbine performance, the project prevented a potentially catastrophic secondary failure by identifying and recovering a missing valve seat fragment before it could enter the steam path. The successful outcome demonstrated Blackstone’s integrated capabilities in steam turbine troubleshooting, field machining, welding, manufacturing, and outage execution when reliability and response time matter most.