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ENGINEERING

This effort led to minimise possible risks of a turna- the installation methods of the project.
round time increase during the execution. Constructability and schedule assessment drove
To support the planning, the project team carried a number of decisions that influenced the execu-
out detailed constructability studies that became a tion of the entire project, from engineering phase
fundamental element for a robust project execution up to construction subcontracts scope throughout
and schedule baseline reference. vendor equipment fabrication and pre-assembly
extent.
Constructability studies - 3D Upfront constructability decisions enabled the
team to address the project requirements at the
simulations - Construction right time, avoiding last-minute turnaround plan
Execution Plan reshuffling.
FCC regenerator replacement in a single piece
•
Physical and time project constraints required the and new isolation valve/flue gas line modula-
identification well in advance of the constructability risation
main aspects: The periodic 4-5 year FCC maintenance con-
• Refinery accessibility; sisting of the traditional replacement of the
• Limited laydown, prefabrication, and access FCC regenerator head with cyclones is already
areas inside the refinery; a well-established work process for the refine-
• Material and personnel logistic; ry, including the lifting plan using a 1,350 tons
• Construction operation interferences with exi- crane. However, during 2019 the FCC regene-
sting infrastructures; rator shell and bottom cone were approaching
• Heavy liftings studies, including cranes selec- the end-of-life status.
tion and booking plan. Due to this, the ‘Turnaround 2020 Project’
The ‘engineering driven by construction’ concept scope included the complete FCC regenera-
was important in the design solutions to support tor replacement. The execution of this activity
became substantially different with respect to
the regenerator and usual head and cyclones
replacement.
The project objective to minimise the turna-
round activities guided the decision to maximi-
se the equipment overall fabrication during the
pre-turnaround phase and lift the FCC regene-
rator in a single piece during the turnaround.
This significantly increased the weight to be
lifted. The overall weight of the FCC regene-
rator fully preassembled including the internal
refractory liner became 550 tons. The high
regenerator dead weight required a specific
equipment mechanical calculation to verify
the resistance to its own load during the lifting
operations.
Space refinery constraints did not allow place-
ment of the crane close to the regenerators fi-
New isolation valve flue gas line module pre-assembly and lifting nal position. Minimum distance between crane

FCC regenerator lifting - 3D simulation and real case

44 44 Impiantistica Italiana - Novembre-Dicembre 2020