Effect of Coking Size on the Thermal Diffusion and Stress Distribution of Cr25Ni35Nb and Cr35Ni45Nb Austenitic Steels

Abstract:

Cr25Ni35Nb and Cr35Ni45Nb austenitic steels, used as furnace tube material in the ethylene pyrolysis furnace, generally suffer from coking during the long operation period. In the present paper, for coked Cr25Ni35Nb and Cr35Ni45Nb austenitic steel, using the finite element ABAQUS code, a sequentially coupled thermal stress procedure was developed to calculate distribution of the temperature and thermal stress field. The results show that thermal diffusion property of Cr25Ni35Nb and Cr35Ni45Nb steel deteriorates obviously with coking layer increasing. Radial bulge and rupture at local field would generate due to excess temperature for applied subsequent measurement. Maximum stress distribute along the cross-section of coking layer and metal matrix. Finally, the critical depth of coking layer of Cr25Ni35Nb and Cr35Ni45Nb austenitic steel are predicted when decoking measurement must be executed.

• Periodical: Applied Mechanics and Materials (Volume 750)
• Pages: 192-197
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.750.192
• Online since: April 2015
• Authors: Li Min Shen*, Jian Ming Gong, Huan Sheng Liu
• Keywords: Coking, Cr25Ni35Nb, Cr35Ni45Nb, Mechanical Property, Thermal Diffusion

References

[1] G. Dini, S.M.M. Vaghefi, M. Lotfiani, et al. Computational and experimental failure analysis of continuous-annealing furnace radiant tubes exposed to excessive temperature, Eng. Fail. Anal. (2008)445-457.

DOI: 10.1016/j.engfailanal.2007.05.007

[2] L.M. Shen, J.M. Gong, Y. Jiang and L.Y. Geng. Damage prediction of HP40Nb steel with coupled creep and carburization based on the continuum damage mechanics. Acta Metall. Sin. (Engl. Lett. ). 25(2012) 279-286.

[3] X.Q. Wu, H.M. Jing, Y.G. Zheng, et al. Coking of HP tubes in ethylene steam cracking plant and its mitigation. Brit. Corros. J. 36(2001)121-126.

DOI: 10.1179/000705901101501541

[4] H.Y. Cai, A. Krzywicki, M.C. Oballa. Coke formation in steam crackers for ethylene production. Chem. Eng. Process. 41(2002) 199-214.

DOI: 10.1016/s0255-2701(01)00135-0

[5] K.S. Guan, F. Xu, Z.W. Wang, et al. Failure analysis of hot corrosion of weldments in ethylene cracking tubes. Eng. Fail. Anal. 12(2005) 1-12.

DOI: 10.1016/j.engfailanal.2004.06.003

[6] K.S. Guan, H. Xu, Z.W. Wang. Analysis of failed ethylene cracking tubes. Eng. Fail. Anal. 12(2005) 420-431.

DOI: 10.1016/j.engfailanal.2004.03.012

[7] A. Goswami, S. Kumar. Failure of pyrolysis coils coated with anit-coking film in an ethylene cracking plant. Eng. Fail. Anal. 39(2014) 181-187.

DOI: 10.1016/j.engfailanal.2014.01.019

[8] S.H. Khodamorad, F.D. Haghshenas, H. Rezaie, et al. Analysis of ethylene cracking furnace tubes. Eng. Fail. Anal. 21(2012) 1-8.

DOI: 10.1016/j.engfailanal.2011.11.018

[9] V. Tari, A. Najafizadeh, M. H. Aghaei, et al. Failure analysis of ethylene cracking tube. Journal of failure analysis and prevention. 9(2009) 316-322.

DOI: 10.1007/s11668-009-9259-5

[10] L.M. Shen, J.M. Gong, X.Y. Qin. Experimental investigation and numerical simulation of carburization layer evolution of Cr25Ni35Nb and Cr35Ni45Nb steel. Rev. Adv. Mater. Sci. 33(2013) 142-147.

[11] K.S. Guan, Q.Q. Wang. Analysis of failed electron beam welds in ethylene cracking tubes. Eng. Fail. Anal. 18(2011) 1366-1374.

DOI: 10.1016/j.engfailanal.2011.04.003