Detailed prediction of olefin yields from hydrocarbon pyrolysis through a fundamental simulation model (SPYRO)

Dente, Mario; Ranzi, E.; Goossens, A.G.

doi:10.1016/0098-1354(79)80013-7

Cited by 146 publications

(93 citation statements)

References 9 publications

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“…Moreover, long computation times were required. That is why an algorithm more specific for chemical kinetics was employed in the present work (Dente et al, 1979). This algorithm makes use of the pseudo-steady-state approximation for the reactive intermediates.…”

Section: Methodsmentioning

confidence: 99%

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Kinetics of the oxidative coupling of methane at atmospheric pressure in the absence of catalyst

Chen

Hoebink

Marin

1991

Ind. Eng. Chem. Res.

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Continuous flow experiments for the oxidative coupling of methane in the absence of catalyst and at low methane conversion were carried out in empty tubular quartz reactors at atmospheric pressure, temperatures from 873 to 1123 K, and inlet molar ratios of CH,/O2 from 4 to 10 and of He/CH4 from 0 to 1.25. The methane conversion varied from 2 to 15% and the oxygen conversion from 10 to 100%. A reaction network was constructed on the basis of elementary free-radical reactions. Arrhenius parameters were estimated for the most important reactions by regression of experimental data. The effects of the process conditions on the conversions of methane and oxygen as well as on the selectivities toward products were simulated adequateliy by considering 33 elementary reactions.Ethane is mainly formed from the recombination of methyl radicals arising from degenerate branched chains involving OH and H 0 2 as main chain carriers. Etlhene originates from ethane mainly via a pyrolytic chain, while the oxidative dehydrogenation contributes to a much lower extent. Carbon monoxide originates from the oxidation of methyl radicals, whereas the contribution of the consecutive oxidation is not significant a t the conversion levels investigated. IntroductionThe oxidative coupling of methane aimed at the production of higher hydrocarbons has attracted much attention during the past years. This reaction is usually carried out in the presence of catalysts and requires temperatures up to 1150 K. At these temperatures, noncatalytic reactions in the gas phase, however, play an essential role in the formation of higher hydrocarbons. It is generally accepted that the most widely studied alkali metal/&aline earth metal oxide and the rare earth metal oxide catalysts act as a methane activator and in particular as a producer of methyl radicals, with the subsequent reactions taking place in the gas phase (Ito et al., 1985). Whether or not the reducible multivalent metal oxides catalyze the reactions in the same way is still in debate.The importance of the gas-phase reactions has been well recognized and is reflected in several recent papers on the oxidative coupling of methane in the absence of catalyst (Labinger and Ott, 1987;Lane and Wolf, 1988;Geerts et al., 1990;Zanthoff and Baerns, 1990). Furthermore, in a recent review, Lunsford (1990) has pointed out the importance of branched-chain reactions in the gas phase with respect to the generation of methyl radicals. Consequently, Lunsford proposed that catalysts might be an important initiator of the chain reaction, but not a major source of methyl radicals. Kinetic models based on the free-radical mechanism have been set up in order to understand the role played by the gas-phase reactions and the interaction between the gas-phase reactions and the reactions on the catalyst surface. The Arrhenius parameters were selected from data bases in the literature that originate mainly from combustion kinetics (Tsang and Hampson, 1986; Warnatz, 1984). While the dependence of the coupling selectivity on co...

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Section: Methodsmentioning

confidence: 99%

“…This algorithm makes use of the pseudo-steady-state approximation for the reactive intermediates. It has been used successfully in kinetic studies of thermal cracking processes (Dente et al, 1979;Clymans, 1982). It reduces computation times by a factor of 10 compared with the Gear algorithm.…”

Section: Methodsmentioning

confidence: 99%

Kinetics of the oxidative coupling of methane at atmospheric pressure in the absence of catalyst

Chen

Hoebink

Marin

1991

Ind. Eng. Chem. Res.

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“…with the stoichiometric coefficients m 0 jk and m 00 jk Various sets of elementary reactions are available for modeling homogeneous gas phase reactions that may matter in catalytic reactors [37,76,77].…”

Section: Gas-phase Reaction Ratementioning

confidence: 99%

Modeling of the Interactions Between Catalytic Surfaces and Gas-Phase

Deutschmann

2014

Catal Lett

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The catalytic surface interacts with the gasphase by a variety of chemical and physical processes. Hence, optimization of design and operation conditions of catalytic reactors do not only require the understanding of the catalytic reaction sequence but also its coupling with mass and heat transport and potential homogeneous reactions. The chemical, thermal, and mass-transport interactions between the catalytic surface and the gas-phase are discussed in terms of the individual and combined interactions. The state-of-the-art modelling of reactive flows and its coupling with the catalytic surface is summarized. The interactions are illustrated by a number of examples such as reforming of hydrocarbons, catalytic combustion, exhaust-gas after-treatment, each focusing on a special aspect of catalyst-gas interactions. The potentials and limitations of the numerical simulations will be discussed including experimental techniques for model validation.

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“…The last four decades much effort has been devoted to the development of detailed mechanistic computer models for use in furnace design and predicting product yields from various types of feedstock over a broad range of cracking conditions. Mathematical modeling has the important advantage that once the model is developed, results can be easily gathered and computer simulations take only a limited time (Dente and Ranzi, 1979). For an accurate description of chemical kinetics applicable over a wide range of process conditions and feedstocks, a detailed microkinetic model is required (Froment, 1992).…”

Section: Introductionmentioning

confidence: 99%

Challenges of Modeling Steam Cracking of Heavy Feedstocks

Reyniers

Marin

2008

Oil & Gas Science and Technology - Rev. IFP

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Résumé -Les défis de la modélisation du vapocraquage des hydrocarbures lourdsActuellement les modèles cinétiques du vapocraquage des hydrocarbures, par événements constitutifs, permettent de simuler la conversion de fractions lourdes. Le principal défi pour modéliser le craquage de ces matières lourdes est leur reconstruction moléculaire. Celle-ci dépend du niveau de précision molécu-laire requis du réseau réactionnel et de la caractérisation/méthode de reconstruction de la charge, comme cela est illustré pour les condensats du gaz naturel par exemple. La comparaison entre les prédictions et les résultats obtenus dans une unité pilote montre comment les incertitudes au niveau de la reconstruction de la charge se propagent au niveau des résultats de la simulation. La combinaison du modèle cinétique par événements constitutifs et de la méthode de reconstruction basée sur la maximisation de l'entropie de Shannon, permet d'obtenir des résultats précis si la densité, la repartition en poids ou en volume des fractions PIONA, et les points d'ébullition initiaux, à 50 % et finals sont connus. Moins il y a d'indices spéci-fiés, moins il y a de correspondance entre les résultats simulés et ceux obtenus par expérimentation. La méthodologie développée peut être très simplement élargie à d'autres coupes pétrolières. Abstract -Challenges of Modeling Steam Cracking of Heavy Feedstocks -Today single event microkinetic (SEMK) models for steam cracking of hydrocarbons allow simulating the conversion of heavy fractions. The key challenge to model the cracking behavior of these heavy feedstocks is related to feedstock reconstruction. The latter depends on the required level of molecular detail of the reaction network and of the feedstock characterization/ reconstruction model. This is illustrated for gas condensate feedstocks. Comparison of yield predictions with yields obtained in a pilot

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Detailed prediction of olefin yields from hydrocarbon pyrolysis through a fundamental simulation model (SPYRO)

Cited by 146 publications

References 9 publications

Kinetics of the oxidative coupling of methane at atmospheric pressure in the absence of catalyst

Kinetics of the oxidative coupling of methane at atmospheric pressure in the absence of catalyst

Modeling of the Interactions Between Catalytic Surfaces and Gas-Phase

Challenges of Modeling Steam Cracking of Heavy Feedstocks

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