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Fig. 6 - Self Propelled Second site phase: turnaround was particularly critical because of very high
Modular Transporter In order to achieve the schedule, Vergaengineering center of gravity of such items. The old radiant
(SPMT) turnaround site jobs were performed on day-and-night modules to be revamped were suitably uncovered

shifts, with no difference in the activities performed (i.e. for the occasion (figure 8), in order to receive the
also critical activities as heavy lifting were indifferently new coils from the top.
carried on during day and night). In details: This way to operate allowed many activities to be
I) at the big rendezvous with turnaround, the new anticipated during the pre-turnaround site works
coils for radiant sections were moved with a Self phase. Of course, this anticipation was paid with
Propelled Modular Transporter (figure 6) to their a higher risk of failing the interfaces between the
final destination (figure 7). This transportation new coil and the old shell. In order to lower such
risk, Vergaengineering performed detailed surveys
of existing heaters during engineering phase, and
contrived many little design expedients to prevent
related issues;
II) even if the revamping of the 20 m convection
coil could seem a quite standard job, its
performance during a big turnaround makes it
a challenging job. In fact, the bundle puller
itself with the related cranes was a
cumbersome presence in a crowded yard
such as a refinery during complete revamping
with simultaneous operations. The issues
were solved with a combination of wise site
management and proper layout design,
studied step-by-step during the engineering
phase;
III) although the prefabricated modules for air pre
heater replacement were assembled very close to
their final destination, a 750 tons crane was
needed to lift them.
Fig. 7 - One modularized coil hanged on top part (arch), lifted from its frame The impact cost of such big crane was however
structure to final destination fully compensate by modular construction, which
lead to great advantages from many points of
views: worksite safety, quality and above all
schedule efficiency. This last point was particularly
critical not only for the general turnaround
schedule constraint, but also for needed time
flexibility. As a matter of fact, the weather has
huge impact on site activities, and the saving of
time given by modularization is of fundamental
importance.
As for the radiant sections revamping, also for air
pre-heater replacement one of the highest
challenges was to fit the interfaces with the
existing battery limits: the existing ducts and
above all the existing foundation.
Fig. 8 - One uncovered old radiant module Again, surveys of existing structures during

IndustrIal Plants - May 2018
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