Ethane Pyrolysis

Hepp, H. J.; Spessard, F. P.; Randall, J. H.

doi:10.1021/ie50479a036

Cited by 12 publications

(5 citation statements)

References 2 publications

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“…In studies with n-hexadecane (Fabuss et aL, 1962) in a 3.2 mm inside diameter by 1.2 m long reactor, the average difference between the reacting gas and the wall temperature (593 0C) was estimated to be about 33 0C, when the uncorrected first order rate constant was 0.06 s. However, when the reaction rate was increased to 0.54 s by increasing the wall temperature to 704° C, the resulting difference between the gas and wail temperature was a substantial 94° C. Residence times varied between 0.25 and 10 s. On the other hand, in a 1 mm inside diameter tubular reactor with residence times of 1 minute, rate constants of up to 0.5 s were obtained with no significant temperature difference between the gas and wall (Sandier and Chung, 1961). The benefits of decreasing the reactor diameter even further were demonstrated b Hepp et al (1949). They were able to measure ethané.…”

Section: Flow Reactorsmentioning

confidence: 99%

Ultrapyrolysis of n-hexadecane in a novel micro-reactor

Fairburn

Behie

Svrcek

1990

Fuel

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Section: Flow Reactorsmentioning

confidence: 99%

Ultrapyrolysis of n-hexadecane in a novel micro-reactor

Fairburn

Behie

Svrcek

1990

Fuel

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“…Process temperatures can potentially be lowered to <500 °C and render the process inherently safe, since the ignition temperature of C 2 H 6 is ≈510 °C. [ 55 ] iii) Depending on the type of the OC and its thermodynamic properties, heat may be generated during the regeneration/oxidation step, which can be utilized within the process.…”

Section: Discussionmentioning

confidence: 99%

Highly Selective Oxidative Dehydrogenation of Ethane to Ethylene via Chemical Looping with Oxygen Uncoupling through Structural Engineering of the Oxygen Carrier

Luongo

Donat

Bork

et al. 2022

Advanced Energy Materials

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The oxidative dehydrogenation of ethane (ODH) to produce ethylene offers advantages compared to the industry standard steam cracking, but its industrial application is hindered by costly air separation units needed to supply oxygen. A chemical‐looping‐based oxidative dehydrogenation (CL‐ODH) scheme is presented, in which oxygen carriers supply gaseous oxygen in situ, which then reacts with ethane in the presence of a catalyst at a comparatively low temperature (500 °C). A common challenge of chemical looping processes beyond combustion is to suppress the overoxidation of hydrocarbons to COx to enable high product yields. It is demonstrated that the overoxidation of ethane can be eliminated completely through structural engineering of the perovskite oxygen carrier involving alkali‐metal‐based carbonate coatings, while maintaining the materials’ ability to generate oxygen. Through CL‐ODH, higher ethylene selectivity (≈91%) and yields (≈39%) are achieved compared to the conventional ODH scheme without oxygen carrier and cofeeding air/ethane. 18O‐labeling experiments demonstrate that the carbonate layer functions like a diffusion barrier for ethane while being permeable for oxygen. Both the CL‐ODH scheme and the material design strategy can be extended to other catalytic oxidation or dehydrogenation reactions requiring oxygen at different temperatures, offering enormous potential to intensify such processes.

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“…11 ( r A p / A ) vs. the experimental result. The molecules presented span a range of approximately 10 orders of magnitude in rate constant and chain lengths from approximately lo3 for dibenzylether (DBE) (LaMarca, 1992), 10' for ethane (Frey and Smith, 1928;Marek and McCluer, 1932;Hepp et al, 1949;Quinn, 1963;Pratt, 1966) and at most 0.1 for bibenzyl (BB) (Poutsma, 1980;Miller and Stein, 1981;Petrocelli and Klein, 1984;Petrocelli, 1985) and benzylphenylamine (BPA) (Abraham and Klein, 1985;Abraham, 1987). The strong correlation in Figure 2 shows the versatility of Eq.…”

Section: Discussionmentioning

confidence: 99%

Simple approximate rate law for both short‐ and long‐chain rice Herzfeld kinetics

1994

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Many high-temperature hydrocarbon conversion processes are based on or contain an element of thermal reaction chemistry. The essential challenge in modeling these pyrolysis reactions stems from the complexity of the hydrocarbon feed. These are often multicomponent mixtures of molecules undergoing the elementary steps of bond fission, hydrogen transfer, @-scission and radical recombination/disproportionation. Mixture components will interact through the bimolecular steps of H-transfer and radical recombination/ disproportionation. Quantitative modeling of these processes requires not only the kinetics of the elementary steps but also a formalism for their assembly into an analytical rate law or the calculation of a numerical scheme.Toward this end, the elementary steps noted above can be organized into a general Rice-Herzfeld chain process comprising initiation, propagation, and termination components, as shown in Figure 1. In deriving a rate law for reactions such as shown in Figure 1, the nonlinearities arising from the bimolecularity (in radical concentration) of the termination step can present a serious mathematical burden when the combinatorial complexities of a mixture need be addressed. However, the chemistry will be such that frequently the disappearance of reactant is predominantly by the propagation cycle of Figure 1. Gavalas (1966) demonstrated the reduction of mathematical complexity that occurs under such a "long kinetic chain" condition. Essentially, the nonlinear problem becomes a linear one.The appeal of this long-chain approximation (LCA), especially for modeling the reaction of mixtures, motivated the present scrutiny of its range of applicability. Limitations were expected because the LCA is more system-specific than, for example, the steady-state approximation, as the structure of the reacting molecule provides the critical balance of propagation vs. initiation rates. Thus, the application of the LCA appeared to require molecule-by-molecule, a-priori inspection. Moreover, because of the high activation energies of initiation, it seemed reasonable to suspect that a given system could shift away from long-chain conditions with increases in temperature. At extremely high temperatures, the highly activated initiation step could be expected to dominate. Approximate Rate LawThis line of reasoning suggested that the simple sum of the initiation plus the long-chain rates might approximate the exact kinetics of RH chains well (Eq. 1). Limiting-case accuracy seemed assured. A reactant with a highly unfavorable 0-scission pathway would have a negligible contribution from the "long-chain rate," and may be well modeled by a simple initiation rate. Conversely, a reactant with a long chain would see a negligible contribution from the initiation rate. It is the goal of the present communication to show that the simple sum of Eq. 1 can be applied to predict the disappearance kinetics of a range of molecules without a-priori knowledge of the chain length. The value of this is that the exact solution

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Ethane Pyrolysis

Cited by 12 publications

References 2 publications

Ultrapyrolysis of n-hexadecane in a novel micro-reactor

Ultrapyrolysis of n-hexadecane in a novel micro-reactor

Highly Selective Oxidative Dehydrogenation of Ethane to Ethylene via Chemical Looping with Oxygen Uncoupling through Structural Engineering of the Oxygen Carrier

Simple approximate rate law for both short‐ and long‐chain rice Herzfeld kinetics

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