Influence of Metal Surface and Sulfur Addition on Coke Deposition in the Thermal Cracking of Hydrocarbons

1995 ◽  
Vol 34 (3) ◽  
pp. 773-785 ◽  
Author(s):  
Marie-Francoise S. G. Reyniers ◽  
Gilbert F. Froment
Author(s):  
Ramin Karimzadeh ◽  
Amin Hematian ◽  
Mohammad Reza Omidkhah

Various parameters such as type of feedstock, inlet and outlet coil temperature, heat flux and residence time, affect the performance of a thermal cracking reactor. The pyrolysis coil configuration is one of the most important parameters which affects the performance of the reactor.In this research the effect of four different coil configurations, namely single row, millisecond, split and reversed split have been studied on run length, product yields, outside surface temperature of coil, coke deposition as well as temperature and pressure distribution. The reactor under investigation is the thermal cracker of Abadan petrochemical complex which uses propane as feedstock. The results show that millisecond coil configuration has the highest yield of ethylene and lowest coke thickness. However, it exhibits the lowest run length and worst ratio of length to diameter conditions. On the other hand, single row coil configuration has the lowest ethylene yield and highest coke thickness but, the highest run length with the lowest pressure drop also belongs to this coil configuration. It also presents the most even distribution of pressure and a linear temperature profile across the coil length, favoring better selectivity.


AIChE Journal ◽  
1981 ◽  
Vol 27 (6) ◽  
pp. 946-951 ◽  
Author(s):  
K. M. Sundaram ◽  
P. S. Van Damme ◽  
G. F. Froment

Author(s):  
Aligholi Niaei ◽  
Darioush Salari ◽  
Jafar Towfighi ◽  
Ahad Chamandeh ◽  
Reza Nabavi

Rate of coke formation during steam pyrolysis of naphtha has been investigated in a laboratory CSTR reactor both for uncoated SS321 and metal coating constructed with thermal spray method with metal powders of aluminum, aluminum-magnesium and zinc. Rate of coke formation was studied in different temperatures and amount of coke as a function of run time has been studied too. The results of the study show that passivating the surface of SS321 with a coating of aluminum and aluminum-magnesium can significantly reduce the rate of coke deposition during naphtha pyrolysis. The results obtained from zinc coated show decoking carry out during thermal cracking. The scanning electron microscope (SEM) was carried out for morphology studied of coke deposited on the different metal surfaces.


1979 ◽  
Vol 34 (5) ◽  
pp. 635-644 ◽  
Author(s):  
K.M. Sundaram ◽  
G.F. Froment

Author(s):  
L.E. Murr ◽  
V. Annamalai

Georgius Agricola in 1556 in his classical book, “De Re Metallica”, mentioned a strange water drawn from a mine shaft near Schmölnitz in Hungary that eroded iron and turned it into copper. This precipitation (or cementation) of copper on iron was employed as a commercial technique for producing copper at the Rio Tinto Mines in Spain in the 16th Century, and it continues today to account for as much as 15 percent of the copper produced by several U.S. copper companies.In addition to the Cu/Fe system, many other similar heterogeneous, electrochemical reactions can occur where ions from solution are reduced to metal on a more electropositive metal surface. In the case of copper precipitation from solution, aluminum is also an interesting system because of economic, environmental (ecological) and energy considerations. In studies of copper cementation on aluminum as an alternative to the historical Cu/Fe system, it was noticed that the two systems (Cu/Fe and Cu/Al) were kinetically very different, and that this difference was due in large part to differences in the structure of the residual, cement-copper deposit.


Author(s):  
A. Elgsaeter ◽  
T. Espevik ◽  
G. Kopstad

The importance of a high rate of temperature decrease (“rapid freezing”) when freezing specimens for freeze-etching has long been recognized1. The two basic methods for achieving rapid freezing are: 1) dropping the specimen onto a metal surface at low temperature, 2) bringing the specimen instantaneously into thermal contact with a liquid at low temperature and subsequently maintaining a high relative velocity between the liquid and the specimen. Over the last couple of years the first method has received strong renewed interest, particularily as the result of a series of important studies by Heuser and coworkers 2,3. In this paper we will compare these two freezing methods theoretically and experimentally.


2001 ◽  
Vol 11 (PR3) ◽  
pp. Pr3-279-Pr3-286
Author(s):  
X. Dabou ◽  
P. Samaras ◽  
G. P. Sakellaropoulos

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