Careers Proven Reliability and Long-Term Performance for Critical Pulp Digester Equipment
At a leading North American pulp and paper facility, the digester is a key part of the continuous pulping process. It runs at high temperature and pressure in a harsh chemical environment. Over time, serious internal corrosion and erosion developed, weakening the vessel walls and threatening long-term reliability.
Evaluating Long-Term Reliability Options
Prior to engaging IGS, the client had utilized conventional weld repairs and various coating applications from other contractors. However, these legacy systems showed accelerated wear and inconsistent corrosion protection, resulting in recurring maintenance costs and increased inspection frequency. IGS was selected for its proven record of digester protection using High Velocity Thermal Spray (HVTS) cladding and its ability to deliver consistent, high-quality metallurgical protection without distortion, heat stress, or extended shutdown durations.
Key factors influencing the client’s decision included:
- Speed of application – up to 3× faster than weld overlay.
- Demonstrated superior alloy performance in similar pulp digestion environments.
- Third-party inspection and validation confirming adherence to IGS Quality Control Plans and industry standards
IGS Solution Delivery
IGS executed the project in three major phases across multiple outages to fully restore the digester’s internal surface. The total treated area amounted to 801 ft² / 74.4 m², including 501 ft² / 46.5 m² of strip-and-replace and 300 ft² / 27.9 m² of new application on bare shell. Surface preparation involved multi-shift precision grinding to remove corrosion damage and achieve the required substrate profile, verified via third-party inspection. The HVTS cladding was applied using a proprietary alloy system, creating a uniform, dense metallurgical bond designed to withstand high thermal and chemical stress zones from the dome to the cone.
Shortened Turnaround Schedule With Proven HVTS Performance
IGS delivered a high-performance solution to restore the Kraft Mill digester with minimal downtime and maximum reliability. Leveraging decades of field-proven methodology and proprietary HVTS cladding, the team completed over 40 shifts of surface preparation and treatment, including precision grinding, blasting, and application, faster than traditional weld overlay methods. Despite the complexity and scale of the work, every step was executed on schedule, under strict safety controls, and with zero rework
Quantifiable Impact and Proven Results
The post-job third-party inspection confirmed the complete and defect-free metallurgical bond across the repaired and newly protected areas. The IGS system demonstrated:
- Extended asset life expectancy.
- Full third-party inspection approval verifying adherence to IGS quality standards.
- Zero rework and no deviations from the Quality Control Plan.
- Zero safety incidents.
- Enhanced reliability of the digester’s shell and cone, reducing future maintenance needs.
“Our goal was to return this critical digester to dependable, long-term operation with minimal downtime. The third-party validation confirmed what we strive for in every project- reliability you can trust.”
– Yelena Rojas, Director of Asset Integrity Solutions, IGS
Future Recommendations and Continued Partnership
Following inspection, IGS recommended continued reapplication of the HVTS system in remaining areas from the weld line to the lower cone to achieve full internal protection. This proactive approach ensures consistency of protection and optimal service life extension.
The IGS HVTS cladding system restored full reliability to a critical digester and earned third-party validation for quality and integrity.
Watch: High-Velocity Thermal Spray, HVTS Solution Alloy Cladding
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