Investigation of ethylene production in naphtha thermal cracking plant in presence of steam and carbon dioxide

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2013-07, Vol.228, p.1158-1167
• Main Authors: Seifzadeh Haghighi, S., Rahimpour, M.R., Raeissi, S., Dehghani, O.
• Format: Article
• Language: English
• Subjects: Carbon dioxide; chemical engineering; Coke; Coke formation; cracking; Cracking in presence of carbon dioxide; Cracking in presence of steam; Ethylene; ethylene production; Fracture mechanics; heat transfer; Mathematical models; Naphtha; Naphtha thermal cracking; olefin; Reactors; temperature; thermal cracking; Tubes
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2013.05.048

[Display omitted] •A mathematical model was developed to describe naphtha thermal cracking.•A comparison between mathematical and plant data show an acceptable agreement.•The diluting media changed to carbon dioxide and the model was run with CO2.•Using carbon dioxide enhances production yields and decrease coke deposition.•Using CO2 increases the run length of reactor from 80 to 100 days. In the present study, a mathematical model for naphtha thermal cracking in the presence of steam is developed. This model can predict the behavior of cracking unit of the olefin plant. In this plant a mixture of steam and naphtha passes through cracking tubes. The major role of steam is partial removal of coke that causes different problems along the reactor such as low heat transfer and high pressure drop. In this study another diluting media such as carbon dioxide is employed instead of steam in order to investigate the effect of carbon dioxide on main products yield and operating conditions. Carbon dioxide was shown to improve not only naphtha conversion but also the yield of ethylene and other main products. It also increases the heat transfer to the coils due to the fact that in presence of carbon dioxide the coke thickness along the reactor reduces dramatically. This analysis suggests that the run length of the reactor in presence of carbon dioxide is 25% higher than that in presence of steam. It is also observed that using carbon dioxide reduces tube wall temperature, resulting in less operating and maintenance costs.