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Fig. 4 - Modularized radiant coils hanged on top Fig. 5 - The biggest module (still uncompleted) during site
part (arch) inside their temporary frame structures prefabrication in the pre-turnaround phase

input to a specific turnaround planning software tool, smaller pieces to be assembled in field. In details:
able to manage in detail all thousands of single site I) the new coils for radiant sections were thus
activities, concerning all fields: fabrication, lifting, completely assembled inside two frame structures,
scaffolding, quality inspections etc. which were appositely erected in a laydown area
Vergaengineering was directly involved in the use of within the refinery (figure 4). The site was so
such highly specialized software tool, during both the windy, that the tall frame structures had to be
planning phase and the site works phase for the constructed with high structural standards, and
consequent updates during step-by-step erection also a temporary foundation was required for the
completion. circumstance;
II) the convection coil replacement did not require
particular activities during pre-turnaround site
Procurement, fabrication and activities, as the new prefabricated coil sectors
transportation phase were already tested at workshop;
III) the highest effort was for the construction of the
Fabrication phase was partially overlapped to big air pre heater modules. These items were
engineering and planning phase. Fabrication also had assembled in a laydown area very close to the
some back-inputs on engineering, and consequently plant to be revamped, in order to minimize the
on planning, which allowed further improvement of the crane operation range due for lifting of modules in
design. final position.
The main challenge related to fabrication was the The modules contained all structures, platforms,
coordination of the workshops spread throughout ladders, tubing, piping and equipment. Moreover,
Europe (mainly: Italy, Romany, Finland, Poland, Belgium to optimize the scaffolding effort, some parts of
and Netherlands) to allow the fabricated items arrive at scaffolding were left in place once the modules
site yard at proper time. In fact, both delay and advance were finished: this allowed to avoid the
were to be avoided, as the restricted site layout needed re-installation of scaffolds needed for the last
to be timely fed, to achieve schedule construction mechanical and paint adjustments of assembled
without space obstruction. system after its final positioning.
A further challenge arose from modules weight.
Since a temporary foundation had to be avoided,
First site phase: pre-turnaround Vergaengineering designed a temporary flooring

Vergaengineering site jobs started five months before structure, which properly distributed the modules
turnaround. In fact the prefabricated modules were so weight on the ground. This flooring structure was
big and heavy, which could not travel across the anchored to removable concrete panels through
continent. Consequently, these were fabricated in hundreds of bolts (figure 5).

IndustrIal Plants - May 2018
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