Senior Flexonics Pathway Fabricates a 60 Ton FCC
Expansion Joint/Ducting System for Phillips Petroleum
For a major turn around at the
Sweeny Refinery, Phillips turned
to Senior Flexonics Pathway for
replacement of the 84" expander
inlet ducting and expansion joint.
This critical line had experienced
“hot cracking” over years of service
and the replacement was designed
to eliminate this problem.
The consulting firm, Refinery
Technology, Inc., was selected to
write the purchase specifications.
The expander inlet line contained
two gimbal expansion joints and
one hinge expansion joint to accommodate
large movements in
three axes. The hinge and gimbal
attachment hardware had to
be massive to handle the design
pressure of 35 psig at 1 300°F.
To avoid pinching of the pipe due
to differential thermal expansion
of the pipe and the rings to which the gimbal and hinge
hardware was attached, the hardware was designed to
float using a standard Senior Flexonics Pathway design
technique.
To assure smooth flow past the expansion joints, the
84" pipes were hot expanded to raise the bellows away
from the pipe. This allowed the use of a flush flow liner to
minimize turbulence.
To minimize the problem of hot cracking in the future,
the welding processes were carefully controlled to minimize
heat input. All weld wire was purchased with the
lowest ferrite level possible. The .75" thick and 1.25"
thick T304H plate used for the ducting and fabricated
elbows was purchased with strict controls on grain size
and alloy content.
The fit up tolerance of the weld ends had to be held to
+1/8" to allow for an automated field welding process
which would speed installation time. To eliminate any
questions about field fit up, the 60 ton double gimbal/
hinge expansion joint assembly was match marked and
precisely pre-offset in Senior Flexonics Pathway’s facility.
It was a special challenge to verify measurements
and make precise adjustments to such a large, heavy
part.
In addition to the expansion joints, the order included 52
tons of 84" diameter T-304H stainless steel ducting and
support structures that attached to the expansion joint
assemblies. The fabrication schedule was expedited all
the way. The shipment was on time for installation after
an actual fabrication time of approximately 10 weeks.
For fast delivery of critical expansion joints for high temperature
applications, call Senior Flexonics Pathway.