Industry:
 Petro-Chemical
Engineering Specialties Used:
Boiling Heat Transfer
Finite
Element
Fitness-for-Service
Situation:
A boiler was opened during a recent turnaround for
inspection and minor repairs. What was found was a
significant failure of the refractory used to protect the
integral tube sheet from hot process gases. When the tube
sheet material is exposed to high temperature, metallurgical
deterioration occurs which significantly reduces its
strength. The boiler was a critical path item for the
turnaround. Therefore, the facility |
Finite Element Model of
the
Waste Heat Boiler Area of Interest
 |
| did not want to replace the integral tube
sheet due to cost and schedule. If the temperature
profile through the tube sheet thickness could be
determined, we would know whether to replace the part or
leave it in service. Solution:
A three-dimensional thermal finite element model (FEM) was
built for a portion of the tube sheet with several tubes.
Convection boundary conditions for both gas heating and
boiling water cooling were calculated and applied to the
model. We found that most of the tube sheet thickness was
below the critical temperature. Because the potential for
metallurgical deterioration of the tube sheet was predicted
by the FEM to be so shallow, we decided to confirm this
by drilling into the tube sheet a short distance at several
locations. The results of this procedure confirmed the analysis findings
and the tube sheet remained in service. |
As Found Condition at the Beginning
of the Turnaround
|
Benefits:
Our rapid analysis of an existing part enabled on-time
completion of the plant turnaround. Argos Engineers is
ready to partner with your turnaround team to evaluate
unexpected findings. Let us provide the analysis input
needed for quality decisions. Make safe choices, but
avoid costly ones that are overly conservative.
Contact Us.
|
