Publikations Einzelansicht

Titel: The High-Temperature Corrosion Resistance of Spun-Cast Materials for Steam-Cracker Furnaces - A Comparative Study of Alumina- and Chromia-Forming Alloys
 

Autor(en):
 
D. Jakobi, P. Karduck und A. von Richthofen
 
Journal: NACE Corrosion 2013
Jahr: 2013
Band: Paper No. 2287
Schlüsselwörter: Alumina, carburization, centrifugal cast alloy, chromia, coke formation, corrosion, high temperature alloy, hydrocarbon, oxidation, oxide scale, radiant coil, spinel, steam cracker


Zusammenfassung:
Steam cracking furnace radiant coils operate under severe alternating conditions with reducing and oxidizing atmospheres and at temperatures even beyond 1,100 °C. In addition to having sufficient creep strength the coil materials should provide excellent resistance against high temperature corrosion and catalytic coke formation at the inner tube surface. In this study, a comparative test method will be presented in which samples from radiant coils are subjected to a cyclic corrosion test in a laboratory testing unit. The tests examine samples at conditions which are similar to those inside a steam cracking furnace and consist of a sequence of alternating cracking in a mixture of steam and hydrocarbons and subsequent decoking with a steam-air mixture. Sample temperature is raised during the cracking cycle up to 1,100 °C to produce a highly aggressive atmosphere corresponding to the most severe phase in the pyrolysis heater. This paper studies the process of materials deterioration from the initial steps of oxidation during the heating-up to the first corrosive attack and finally to the state in which the high temperature resistance of the material is starting to fail. Secondly, the tests were applied to different state-of-the-art spun cast alloys to work out differences between alloys with a chromia- or spinel-based oxide protection and alloys which are protected by alumina. The testing procedure was optimized to obtain distinct results in affordable time and under conditions still representative for the actual cracker operation. Key words: Alumina, carburization, centrifugal cast alloy, chromia, coke formation, corrosion, high temperature alloy, hydrocarbon, oxidation, oxide scale, radiant coil, spinel, steam cracker

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Publikations Einzelansicht

Titel: The High-Temperature Corrosion Resistance of Spun-Cast Materials for Steam-Cracker Furnaces - A Comparative Study of Alumina- and Chromia-Forming Alloys
 

Autor(en):
 
D. Jakobi, P. Karduck und A. von Richthofen
 
Journal: NACE Corrosion 2013
Jahr: 2013
Band: Paper No. 2287
Schlüsselwörter: Alumina, carburization, centrifugal cast alloy, chromia, coke formation, corrosion, high temperature alloy, hydrocarbon, oxidation, oxide scale, radiant coil, spinel, steam cracker


Zusammenfassung:
Steam cracking furnace radiant coils operate under severe alternating conditions with reducing and oxidizing atmospheres and at temperatures even beyond 1,100 °C. In addition to having sufficient creep strength the coil materials should provide excellent resistance against high temperature corrosion and catalytic coke formation at the inner tube surface. In this study, a comparative test method will be presented in which samples from radiant coils are subjected to a cyclic corrosion test in a laboratory testing unit. The tests examine samples at conditions which are similar to those inside a steam cracking furnace and consist of a sequence of alternating cracking in a mixture of steam and hydrocarbons and subsequent decoking with a steam-air mixture. Sample temperature is raised during the cracking cycle up to 1,100 °C to produce a highly aggressive atmosphere corresponding to the most severe phase in the pyrolysis heater. This paper studies the process of materials deterioration from the initial steps of oxidation during the heating-up to the first corrosive attack and finally to the state in which the high temperature resistance of the material is starting to fail. Secondly, the tests were applied to different state-of-the-art spun cast alloys to work out differences between alloys with a chromia- or spinel-based oxide protection and alloys which are protected by alumina. The testing procedure was optimized to obtain distinct results in affordable time and under conditions still representative for the actual cracker operation. Key words: Alumina, carburization, centrifugal cast alloy, chromia, coke formation, corrosion, high temperature alloy, hydrocarbon, oxidation, oxide scale, radiant coil, spinel, steam cracker

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