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Showing 1 to 20 of 20 for “"coke formation"”.
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Chemistry of alkylaromatics in crude oil upgrading
… sources. In typical carbon rejection processes, coke formation is a common phenomenon that would lead to decreased yield of upgraded oil. As a result, the chemical behavior of coke formation is a potent area of research. Due to the high complexity of the composition of crude oil and coke, this …
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Methanol conversion to olefins and propene oligomerization over modified SAPO-34 and dealuminated mordenite
… molecular sieve, is highly selective in the formation of ethene and propene from methanol, but deactivates rapidly due to coke formation. This catalyst was synthesized and modified in various ways in an attempt to increase the catalyst lifetime and selectivity to ethene. Mild hydrothermal …
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Experimentelle und theoretische Ansätze zur Entschwefelung eines mit Kohlenwasserstoffen beladenen Gases
… the catalyst undergoes a deactivation through coke formation. In order to explain the coke profile in the inner of the catalyst's pellet, the influence of the internal heat and mass transfers has been considered using a pore network.
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Zeolite deactivation during hydrocarbon reactions: characterisation of coke precursors and acidity, product distribution
… processes. However, there is always formation and retention of heavy by-products, called coke, which causes catalyst deactivation. This deactivation is due to the poisoning of the acid sites and/or pore blockage. The formation of coke on hydrocarbon processing catalysts is of …
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Multi-scale modeling tools for coupled reaction, phase equilibrium and two-phase mixing phenomena with application to supercritical water heavy oil upgrading process
… for high distillate liquid yields with lower coke formation, is a complex process involving coupled reactions, phase equilibrium and two-phase mixing phenomena. This thesis presents the development of a range of models and tools to simulate such processes at different scales with varying …
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ADVANCED BIFUNCTIONAL CORE-SHELL CATALYSTS FOR METHANE REFORMING USING CARBON DIOXIDE
… from rapid catalyst deactivation by sintering, formation of coke or poisoning by contaminants severely limit the industrial implementation of this technology. The research presented in this PhD thesis aims at developing Ni-containing catalysts with high activity and long-term stability in DRM, …
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The inertisation of the zeolites ZSM-5, mordenite and beta by chemical vapour deposition using tetraethoxysilane
… and behaves in a non-shape selective manner. Coke formation on the external surface of zeolites may prevent access to the channel system of the zeolite due to pore blocking. It would thus be of great benefit to study the effects of inertising the external acidity of zeolites, thereby enhancing …
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Aplicação de termogravimetria acoplada à espectrometria de massas para caracterização de petróleo e determinação da curva de evolução de gás sulfídrico
… to indicate the nature of oil, its tendency in coke formation, temperatures of distillation and cracking, and other features. It was observed in MS evaluations the behavior of oil main compounds with temperature, the points where the volatilized certain fractions and the evaluation gas analysis …
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The oligomerization of propene over nickel synthetic mica-montmorillonite
… deactivation of the catalyst by increasing the formation of "graphitic" coke. The lifetime of NiSMM is greatly reduced by using a wet propene feed and reacting at higher temperatures (443 K) due to the generation of Bronsted sites and increased coke formation rates, respectively. Deactivation of …
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In-Situ Upgrading and Recovery Enhancement of Athabasca Bitumen by Ultra-Dispersed Nanocatalysts
… enhanced the hydrocracking reactions by reducing coke formation as well as reduction of carbon dioxide emission, which reduces the environmental impact of nanocatalysts on the in-situ upgrading processes.
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Viscosity and Stability of Visbroken Fractionated Oils
… the oil (cause asphaltene precipitation and coke formation). De-asphalting decreases the oil density and can allow more intensive visbreaking without destabilizing the oil. These processes can be applied to both bitumen and vacuum bottom feeds. In all cases, it is necessary to predict the …
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Developing an energy efficient steam reforming process to produce hydrogen from sulfur-containing fuels
… ethylene which generates surface carbon species (coke) that mask catalytic sites. The amount of coke increased during time on stream and became increasingly graphitic. However, the deactivation due to both sulfur adsorption and coke formation was reversible with air treatment at 650C. However, …
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Production of Mesophase Pitch from Gasified Lignin-Derived Tars
… has been shown to completely eliminate its formation. As a result, the tar is being used to manufacture low value products such as asphalt, or is being used as a fuel in fixed combustion systems.</p> <p>The research presented here is part of an effort to increase the viability of using …
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Nanocomposite catalysts for soot combustion and propane steam reforming
… grafting to improve the catalytic activity and coke resistance of the optimal nickel aluminate catalyst. Catalytic activity could be improved by introducing metal promoters in the order of Re > Rh > Pt > Ir > Pd > Ru > V. These selected additives provided increased reducibility and active …
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Catalytic Cracking Of Hydrocarbons With Novel Metal Traps
… also affect hydrogen transfer resulting in more coke formation and reducing light gases.;New catalysts, so-called FCCT (catalysts for FCC with "in situ metal traps"), were developed in this study to achieve high dispersion of passivators. FCCTs were extensively tested and demonstrated …
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Predicting organosulfur chemistry in fuel sources
… the need for a hydrogen feed, and minimizes coke formation. Previous research has shown that it has the potential to be a viable commercial process, and recent experimental studies have proven that water acts as one hydrogen source for sulfur removal in this process. However, the exact …
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Development and characterization of an impedance-based carbon sensor for the detection of catalyst coking in steam-methane and dry-methane reforming systems
… order of several hundred millivolts) to carbon formation on the surface under both of the reforming environments studied. Field-emission scanning electron microscope (FESEM) imaging showed surface catalyst (Ni) particles encapsulated in films of carbon. Sensors were regenerated using steam and …
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Partial Upgrading of Bitumen Through Combinations of Deasphalting and Visbreaking
… density but risks asphaltene precipitation and coke formation at high conversions. Solvent deasphalting separates out the densest, most viscous components from the oil but would also remove too much of the valuable oil components to achieve pipeline specifications. Combinations of the two …
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Effects of phosphorus on bond rupture during hydrodeoxygenation and dehydrogenation reactions on ruthenium
… of P atom on light alkane dehydrogenation and coke formation (i.e., a problem common to dehydrogenation catalysts) using Ru(0001). Cyclohexene was used as a probe molecule, and the RMBS of cyclohexene demonstrated that the addition of P atoms enhances the selectivity of cyclohexene …
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The effect of zeolite type on the hydrocracking of long n-paraffins
… lifetime) of the catalyst through a reduction in coke formation. The results of this investigation indicated that medium pore zeolites show significant potential for use in the selective hydrocracking of a Fischer-Tropsch wax feedstock. It was found that those zeolites possessing medium sized …