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Coke formation in the transfer line exchanger during steam cracking of hydrocarbons / Kevin M. Van Geem in Industrial & engineering chemistry research, Vol. 48 N° 23 (Décembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10343–10358 Titre : Coke formation in the transfer line exchanger during steam cracking of hydrocarbons Type de document : texte imprimé Auteurs : Kevin M. Van Geem, Auteur ; Inge Dhuyvetter, Auteur ; Serge Prokopiev, Auteur Année de publication : 2010 Article en page(s) : pp. 10343–10358 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Coke  Formation--Transfer--Line  Exchanger--during  Steam--Cracking  --Hydrocarbons Résumé : Coke formation under transfer line exchanger conditions, that is, at temperatures from 623 to 873 K and atmospheric pressure, is studied in an electrobalance setup. The coking rate is initially very high (catalytic coking) and drops after a few hours to a constant value. At the studied conditions the observed coking behavior on 15Mo3 alloy pigs can be explained via a catalytic mechanism only, and contributions of the free-radical mechanism and the condensation mechanism are insignificant. Experiments with ethane and naphtha steam cracking effluents and with well-defined reaction mixtures show that the coking rate is independent of the partial pressure of ethene (0−2.7 × 104 Pa), ortho-xylene (0−1.0 × 104 Pa), heavy aromatic hydrocarbons (0−3.0 × 102 Pa), and also 1,3-butadiene (0−2.7 × 104 Pa). The rate of coke deposition depends only on the temperature and the ratio of the partial pressures of water to dihydrogen. The activation energy for initial coke formation was estimated to be ∼90 kJ/mol, a value close to the experimentally determined diffusion energy of carbon in iron. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900124z [article] Coke formation in the transfer line exchanger during steam cracking of hydrocarbons [texte imprimé] / Kevin M. Van Geem, Auteur ; Inge Dhuyvetter, Auteur ; Serge Prokopiev, Auteur . - 2010 . - pp. 10343–10358. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10343–10358 Mots-clés : Coke  Formation--Transfer--Line  Exchanger--during  Steam--Cracking  --Hydrocarbons Résumé : Coke formation under transfer line exchanger conditions, that is, at temperatures from 623 to 873 K and atmospheric pressure, is studied in an electrobalance setup. The coking rate is initially very high (catalytic coking) and drops after a few hours to a constant value. At the studied conditions the observed coking behavior on 15Mo3 alloy pigs can be explained via a catalytic mechanism only, and contributions of the free-radical mechanism and the condensation mechanism are insignificant. Experiments with ethane and naphtha steam cracking effluents and with well-defined reaction mixtures show that the coking rate is independent of the partial pressure of ethene (0−2.7 × 104 Pa), ortho-xylene (0−1.0 × 104 Pa), heavy aromatic hydrocarbons (0−3.0 × 102 Pa), and also 1,3-butadiene (0−2.7 × 104 Pa). The rate of coke deposition depends only on the temperature and the ratio of the partial pressures of water to dihydrogen. The activation energy for initial coke formation was estimated to be ∼90 kJ/mol, a value close to the experimentally determined diffusion energy of carbon in iron. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900124z