Coke Drum Cone Replacement During Refinery Turnaround

Global Mobilisation Under Extreme Turnaround Pressure

A leading Western European refinery scheduled simultaneous cone replacement on four coke drums within a single turnaround window.

Mid-project, newly fabricated cones were found to be slightly out of specification, causing a complication.

In heavy-wall coke drum geometry, “slightly” can translate into distortion, misalignment, or cumulative delay across parallel work fronts. Maintaining dimensional control became the defining challenge.

Scope of Work

  • Replacement of four coke drum cones
  • Controlled cutting and shell preparation
  • Precision fit-up and welding
  • Automated Gas Tungsten Arc Welding (GTAW) process
  • Spider support system to mitigate deformation
  • Parallel execution across four drums

Geometry preservation was critical to avoid shell ovalization, weld misalignment, or downstream structural consequences.

Engineering Controls

Custom Spider Support System

A purpose-designed internal spider system was installed to stabilize shell geometry during cone removal and replacement.

The objective was to prevent deformation before it occurs, not correct it afterward.

In large-diameter vessels, uncontrolled cutting can introduce stress redistribution and dimensional drift. The spider system maintained circumferential stability throughout the operation.

 

Cut-Line Verification and Dimensional Discipline

Before removal, cut-lines were verified against actual field geometry, not just fabrication drawings.

Given the cone dimensional variance, precision fit-up planning was essential to:

  • Maintain roundness
  • Control shrinkage during welding
  • Avoid cumulative alignment error
  • Protect adjacent weld seams

 

Automated GTAW for Consistency

Automated GTAW welding was selected to provide:

  • Controlled heat input
  • Repeatable penetration profile
  • Uniform weld quality across all four drums

In parallel drum execution, consistency across shifts and units is fundamental to maintaining inspection predictability and schedule integrity.

 

Parallel Execution with Shift Continuity

Four drums were executed simultaneously, requiring:

  • Structured shift coordination
  • Defined progress handover protocols
  • Integrated QA/QC sequencing

Continuity of progress, particularly across night shifts, ensured no loss of momentum within the turnaround window.

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The Outcome

  • Four coke drum cones successfully replaced
  • Dimensional control maintained across all units
  • No distortion-driven rework
  • No schedule delays
  • Turnaround completed as planned

Project Leadership

Project Manager: Antoni Zarychta – View Profile
Nightshift Site Supervisor: Piotr Kawalec – View Profile
Nightshift Foreman: Piotr Rychlik – View Profile
Welding Engineering: André Roodzant – View Profile

Learn more about welding controls and coke drum mitigation strategies.

 

 

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WATCH VIDEO:  Automated Weld Overlay