Influence of sulfurization on coke formation over catalysts for naphtha reforming

1986 ◽  
Vol 23 (1) ◽  
pp. 15-22 ◽  
Author(s):  
J.M. Parera ◽  
R.J. Verderone ◽  
C.L. Pieck ◽  
E.M. Traffano
Author(s):  
R. L. Freed ◽  
M. J. Kelley

The commercial introduction of Pt-Re supported catalysts to replace Pt alone on Al2O3 has brought improvements to naphtha reforming. The bimetallic catalyst can be operated continuously under conditions which lead to deactivation of the single metal catalyst by coke formation. Much disagreement still exists as to the exact nature of the bimetallic catalyst at a microscopic level and how it functions in the process so successfully. The overall purpose of this study was to develop the materials characterization tools necessary to study supported catalysts. Specifically with the Pt-Re:Al2O3 catalyst, we sought to elucidate the elemental distribution on the catalyst.


Author(s):  
NORA S. FÍGOLI ◽  
JORGE N. BELTRAMINI ◽  
AMADO F. BARRA ◽  
ELOY E. MARTINELLI ◽  
MARIO R. SAD ◽  
...  

Author(s):  
Mohammad Mahdavian ◽  
Shohreh Fatemi ◽  
Ali Fazeli

Nowadays, with the worldwide, increasing demands of the high qualitative gasoline, it is necessary to establish new naphtha reforming units and develop the traditional units to the high efficiency processes. In this work, according to the recent progresses in naphtha reforming technology, a mathematical modeling of a continuous catalytic reformer with catalyst recirculation is developed for simulation and optimization of the new industrial continuous reformers. The process model uses an extended version of the kinetic model reported by Padmavathi, with some modifications on kinetic constants, and it considers the deactivation rate of the catalyst and pressure drop within the reactor. The process model is based on a 12-lumped kinetics reaction network and has been proved to be quite effective in terms of an industrial application. The naphtha is based on 25-lumped pseudocomponents (including C6 to C10 hydrocarbons) in three categories of n-paraffins, isoparaffins, naphthens, including cyclopentanes and cyclohexanes, and aromatics. The light hydrocarbons product, consisting of C1 to C5 n-paraffins, is taken into account as the products of hydrocracking reaction. First, the kinetic parameters of the reactions are tuned using real results of the outlet temperatures and components in industrial operating conditions. At the next stage, validation of the model was carried out using a new naphtha feed in industrial scale. The final stage of this research was based on splitting a naphtha feed using its only ASTM boiling point and specific gravity, to converting to the components and applying into the process model to predict the outlet temperature and composition, the reformate yield and RON, hydrogen and LPG product, and coke formation at each cycle. The predicted and commercially reported results agreed with each other.


1980 ◽  
Vol 45 (1) ◽  
pp. 238-254 ◽  
Author(s):  
Martin Bajus ◽  
Václav Veselý

The effect of elemental sulfur on the kinetics and selectivity of conversion of heptane was studied with regard to the inhibition of the coke formation during pyrolysis of raffinates from naphtha reforming. The experiments were conducted in stainless steel tubular through-flow reactors at atmospheric pressure. The heptane decomposition rate in the absence of sulfur was compared with that in the presence of 0.01, 0.02, and 0.1 wt.% sulfur at 700°C and with the steam-to-feed ratio 3:1. The influence of the inner surface of the reactor was investigated by using reactors with different equivalent volumes. The effect of sulfur on the coke formation during the pyrolysis of the reformer raffinate was examined at 820°C without any inert diluent.


Author(s):  
Clifford S. Rainey

The spatial distribution of V and Ni deposited within fluidized catalytic cracking (FCC) catalyst is studied because these metals contribute to catalyst deactivation. Y zeolite in FCC microspheres are high SiO2 aluminosilicates with molecular-sized channels that contain a mixture of lanthanoids. They must withstand high regeneration temperatures and retain acid sites needed for cracking of hydrocarbons, a process essential for efficient gasoline production. Zeolite in combination with V to form vanadates, or less diffusion in the channels due to coke formation, may deactivate catalyst. Other factors such as metal "skins", microsphere sintering, and attrition may also be involved. SEM of FCC fracture surfaces, AEM of Y zeolite, and electron microscopy of this work are developed to better understand and minimize catalyst deactivation.


1999 ◽  
Vol 96 (2) ◽  
pp. 303-318 ◽  
Author(s):  
G. A. Doka Nassionou ◽  
P. Magnoux ◽  
M. Guisnet

Author(s):  
Reza Yazdanpanah ◽  
Eshagh Moradiyan ◽  
Rouein Halladj ◽  
Sima Askari

Aim and Objective: The research focuses on recent progress in the production of light olefins. Hence, the common catalyst of the reaction (SAPO-34) deactivates quickly because of coke formation, we reorganized the mechanism combining SAPO-34 with a natural zeolite in order to delay the deactivation time. Materials and Methods: The synthesis of nanocomposite catalyst was conducted hydrothermally using experimental design. Firstly, Clinoptilolite was modified using nitric acid in order to achieve nano scaled material. Then, the initial gel of the SAPO-34 was prepared using DEA, aluminum isopropoxide, phosphoric acid and TEOS as the organic template, sources of Aluminum, Phosphor, and Silicate, respectively. Finally, the modified zeolite was combined with SAPO-34's gel. Results: 20 different catalysts due to D-Optimal design were synthesized and the nanocomposite with 50 weight percent of SAPO-34, 4 hours Crystallization and early Clinoptilolite precipitation showed the highest relative crystallinity, partly high BET surface area and hierarchical structure. Conclusion: Different analysis illustrated the existence of both components. The most important property alteration of nanocomposite was the increment of pore mean diameters and reduction in pore volumes in comparison with free SAPO-34. Due to low price of Clinoptilolite, the new catalyst develops the economy of the process. Using this composite, according to formation of multi-sized pores located hierarchically on the surface of the catalyst and increased surface area, significant amounts of Ethylene and Propylene, in comparison with free SAPO-34, were produced, as well as deactivation time that was improved.


1987 ◽  
Vol 52 (7) ◽  
pp. 1701-1707 ◽  
Author(s):  
Miloslav Křivánek ◽  
Nguyen Thiet Dung ◽  
Pavel Jírů

The catalytic activity of Na, H-Y zeolite samples with a varying Si/Al ratio (2·5 to 20) in the transformation of methanol was determined. The amounts of formed individual aliphatic hydrocarbons as function of reaction time were correlated with the amount of Bronsted and Lewis centres on the catalysts. The effect of coke formation on the over-all course of the reaction has been demonstrated.


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