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Case Study: Innovation and exemplary precision

Case Study: Innovation and exemplary precision

Module Assembly for Coke Drum Structure Delayed Coker Unit (DCU)

The project team of Essar Projects India completed the installation of derrick supporting structure modules (a total of three) in Delayed Coker Unit (DCU) at Essar's Vadinar site for refinery expansion project, using an innovative erection technique.

The normal practice at refinery locations is that these structures are fabricated by pre-assembling the members, erecting the frames, interconnecting the beams and later on filling up all the balance members. This sequence of activities normally takes 3-4 months to complete the structure.

At Vadinar, the entire structure 52 x 13 x 34 m was fabricated in three modules. Fabrication, assembly, painting and finishing was taken up in one complete sequence instead of doing it partially.

Erection of these three modules was completed within just 11 days after the four Coke Drums were erected with the following accomplishments:

  • Perfect Designing and Detailing: Actual deflection only 5 mm in such a long span of 52 m.  
  • Accurate fabrication: Total number of bolts 1,760 (foundation bolts 160 and splice joint 1,600) were fit within 4-5 hours in the column without any gas cutting.
  • Extraordinary Rigging: Total 1,581 Members inserted through the structure between the Coke Drum where the actual Gap is 250 mm only.  
  • This critical erection operation was done with two cranes LR 1600 (650 mt capacity) and Demag CC-6800 (1200 mt capacity).

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