Damage assessment and maintenance strategy ofhydrogen reformer furnace tubes
✍ Scribed by Jian-Ming Gong; Shan-Tung Tu; Kee-Bong Yoon
- Publisher
- Elsevier Science
- Year
- 1999
- Tongue
- English
- Weight
- 842 KB
- Volume
- 6
- Category
- Article
- ISSN
- 1350-6307
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✦ Synopsis
The states of damage along a reformer tube in service for 09 years are metallographically analyzed[ Damage levels are ranked relating to remaining life[ The damage distribution is obtained for the whole reformer tube[ The results show that the accumulated damage of the tube is non!uniform[ The damage level in the lower part of the reformer tube is signi_cantly higher than that in the upper part\ especially in the weld region[ The damage localization is also veri_ed by use of a continuum damage mechanics _nite element technique[ Accordingly it is proposed that local replacement might be a desirable method to extend the service life when the lower part of the reformer tube reaches the safe rupture life[ Þ 0888 Elsevier Science Ltd[ All rights reserved[ Keywords] Creep^Damage assessment^Maintenance^Metallurgical examination^Plant life monitoring 0[ Introduction Reformer furnace tubes are the key components used to produce hydrogen!rich gas from a mixture of hydrocarbons and steam at high temperature[ According to the American Petroleum Institute "API# Recommended Practice 429 ð0Ł\ the furnace tubes are generally designed for a nominal life of 099\999 h "00[3 years#[ The actual service life\ however\ varies from 29\999 to 079\999 h\ depending on the quality of materials and the service conditions[ Reformer furnace tubes are generally fabricated from centrifugally cast creep resistant austenitic steel HK Grade "14Cr\ 19Ni\ 9[3C# or HP Grade "15Cr\ 24Ni\ 9[3C#[ In long term service under high temperature\ the material microstructure is subjected to degradation[ Carbon precipitation occurs in the early stages[ The coalescence and coarsening of the carbides results in embrittlement