Characterization of Thermal-Mechanical Properties and Optimal Selection of Coke Drum Materials

• Author / Creator

  Rahman, Hafijur

• Coke drums, critical equipment in petroleum industry, experience severe thermal-mechanical loading during operations and, the safety and integrity of the coke drum are important to the industries. The tendency of material selections of the coke drum is increasing towards with higher content of Chrome and Molly as the base and 410S stainless steel as the cladding material. Coke drums made of these materials are still experiencing the same type of failure or damage due to high stress developed in the coke drum shell during the operation. The thermo-elastic behavior of the coke drum with currently used materials under thermal and mechanical cyclic loadings is analyzed by using finite element method. It is found that the mismatching of coefficient of thermal expansions of the clad and base materials of coke drum is the main reason to induce very high stress in clad layer that can exceed its yield strength. An alternative combination of SA302B as the base and nickel alloy N06625 as the cladding material is suggested; with this new combination the stress developed in the drum shell is very low according to the coupled thermo-elastic analysis due to their matching coefficient of thermal expansions. The thermal-mechanical properties of those materials are experimentally obtained in the laboratory. To find more accurate and practical results, thermal elastic-plastic analysis is also performed for both pairs of clad and base materials. It is found that permanent deformation is caused in the first cycle of operation and plastic shakedown occurs in the clad layer of the coke drum with the currently used material combination. But there is no permanent deformation happened in the coke drum shell with the new selected material combination, which can be recommended as an optimal material combination for the coke drum.

• Subjects / Keywords

  • Coupled thermo-elastic analysis
  • Cyclic thermal-mechanical loading
  • Coke drum
  • Thermal-mechanical properties
  • Finite element analysis (FEA)

• Graduation date

  Fall 2015

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3542JH3B

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.