Session: DA-02-01 Design and Analysis of Piping and Components - 1

Paper Number: 83678

83678 - Refractory Stiffness Consideration for Modeling Pipe Bends 

Refractory is commonly used in pipes for cold wall design. Generally, to analyze refractory lined piping, a  piping stress analysis software is used. In the stress analysis, the refractory weight and stiffnesses are included in the piping model. In the piping model, combined stiffnesses of the refractory and piping material are used. The combined stiffness procedure was published by Chadda [1] and it is widely adopted in the industry for the analysis of refractory lined pipes. From the piping analysis, the sustained and expansion stresses are compared with ASME B31.3 allowable stresses and the forces and moments from the analysis are used in the design of attached equipment (vessel nozzle, valves, expansion joints etc.) piping restraints and supports.

In this paper it will be shown that for a piping stress analysis, using the combined stiffness of the refractory and pipe material on the straight section of the pipe is satisfactory but when it is used on the bends, it will result in un-conservative resultant forces and moments. To obtain satisfactory resultant forces and moments, the calculated refractory stiffnesses on the bends should be increased in the piping model. The piping stress analysis results were verified with finite element results and past experimental work.

Presenting Author: Chithranjan Nadarajah Becht

Presenting Author Biography: Dr. Nadarajah is a mechanical engineer, and he has been working in the petrochemical industry for more than twenty-five years. He is currently a Senior Fellow at Becht and his expertise is pressure vessel, piping and storage tank design, analysis and fitness for service. Prior to working at Becht, Dr. Nadarajah worked at ExxonMobil Research and Engineering, providing worldwide support to downstream, chemical and upstream facilities.<br/><br/>Dr. Nadarajah is a former member of API-650 design committee, and he is currently a member of the working group on ASME Section VIII, Div.2 Design by Analysis and the Secretary of the ASME Elevated Temperature Design group. Dr. Nadarajah has published more than 25 papers in leading journal and conferences, and he obtained his Bachelors in Mechanical Engineering and Ph.D. from University of Strathclyde, in Glasgow, United Kingdom.

Authors:

Chithranjan Nadarajah Becht