Session: DA-01-05 Design and Analysis of Heat Exchangers and Components

Paper Number: 123468

123468 - Case Study: Tube Plugging Evaluation Using Finite Element Analysis Method for Waste Heat Boiler 

Multiple tubes had suffered from wall thinning of a reformer transfer line exchanger.  Tube plugging was considered to reduce downtime of the equipment in lieu of the complex process of repair or replacement with new replacement tubes.  A case study is presented to demonstrate how to evaluate the effect of tube plugging for flexible tubesheet shell-side steam generating heat exchanger designs.

The finite element method was used to calculate the stress of the heat exchanger for the plugged tube scenario. Sequentially coupled thermal stress analysis was performed. The steady-state temperature profile of the tube and tube sheet was first calculated, and the temperature profiles were used for stress calculation.  The stress results were compared to the ASME Section VIII Div.1 Part UHX allowable load limits. Although Part UHX prescribes the limit of compressive tress for tubes, the buckling failure mode is not explicitly considered. ASME Section VIII Div.2 Part 5 buckling analysis was performed to determine the minimum tube plugging thickness. The analysis considered the compressive load limit from Part UHX and shell side external pressure. The results found that the tube plugging is feasible. However, depending on the pattern, plugging tubes could increase the stress for non-plugged tubes and tube sheets. Therefore, evaluation of tube plugging is required to ensure the integrity of the heat exchanger. 

Presenting Author: Forrest Gu Becht

Presenting Author Biography: Mr. Gu is a Professional Engineer (P.Eng.) registered in Alberta, Canada specializing in mechanical design and integrity with finite element analysis. He is proficient in ASME Section VIII (Division 1 and Division 2), API 579-1/ASME FFS-1 (Level 1, 2, and 3), ASME Section III, EJMA, etc. He has more than 5 years of experience of using Abaqus for linear and nonlinear finite element analysis.

Authors:

Forrest Gu Becht
Louis Pasnik Becht
Derrick Pease becht
Trevor Seipp Becht