Global Mobilisation Under Extreme Turnaround Pressure

When one of the world’s largest integrated refining and petrochemical complexes identified deep OD/ID cracking across multiple coke drums, immediate action was required. 

Cracks extended to depths of 25–30 mm along the can sections, reaching up to 10 linear meters. The scope included structural weld overlay using Inconel 625 (two-layer system) across six drums executed in parallel. 

Shutdown window: 14 days
Total manpower: 260+ personnel

The Challenge

Delayed coke drums operate under some of the most severe cyclic thermal conditions in refining – repeated heating to ~500°C / 930°F followed by rapid water quench. Over time, this daily expansion and contraction drives fatigue cracking at both OD and ID surfaces. 

In this case: 

• Cracks extended 25-30 mm deep 

• Indications reached up to 10 linear meters per drum 

• Multiple drums required simultaneous intervention 

The scope required more than localized repair. Structural margins had to be restored quickly without compromising long-term fatigue performance. 

Engineered Scope of Work

The repair strategy was designed not just to address cracking, but to redistribute cyclic stress and slow future fatigue progression. 

Scope included: 

• Two-layer structural weld overlay using Inconel 625 

• OD and ID crack excavation and remediation 

• Cone section crack repairs 

• Parallel execution across six drums 

The overlay system was selected to provide structural reinforcement while accommodating cyclic strain demand typical of delayed coking service. 

The limitations of traditional approaches 

Conventional corrosion mitigation methods were largely developed for lower-severity operation and shorter run lengths. Under today’s higher temperatures, aggressive chemistries and extended cycles, organic coatings degrade rapidly. Material upgrades become costly and disruptive, and increased maintenance frequency directly erodes the efficiency gains operators are trying to achieve. In some cases, traditional approaches also introduce new constraints.  

“Conventional repair methods would have added 10-12 days to the turnaround schedule”, one refinery noted, “creating significant production and cost impacts”.  By contrast, the use of High Velocity Thermal Spray (HVTS®) enabled targeted protection without extending outage duration. This highlights how advanced corrosion solutions can directly influence operational flexibility and overall efficiency.  

As a result, operators are often forced into a trade-off: pushing equipment to achieve higher throughput and efficiency, while accepting higher corrosion risk, or constraining operating severity to remain within the limits of traditional corrosion protection methods. 

Neither is a sustainable solution.