Gas-phase oxypyrolysis of light alkanes

Arutyunov, V. S.; Magomedov, R. N.

doi:10.1070/rc2012v081n09abeh004267

Cited by 33 publications

(11 citation statements)

References 15 publications

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“…As a result, the total yield of ethyl ene and propylene decreased at elevated temperatures. The quick increase in the contribution of gas phase processes with temperature led to a reduction of the yield of СО 2 , which predominantly formed in hetero geneous reactions on the surface of the reactor [11,15]. The continuous increase in the yield of methane with temperature (table) and the decrease in the yield of CO above 750°C indicates that the contribution of thermal cracking to propane conversion increased.…”

Section: Results Of Experimentsmentioning

confidence: 92%

Effect of oxygen concentration on the oxidative conversion of propane

Pogosyan

Arsentiev

et al. 2015

Russ. J. Phys. Chem. B

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The influence of the initial concentration of oxygen and temperature on the oxidative conversion of propane in a two sectional flow reactor at constant pressure and contact time was studied. It was shown that an increase in the initial concentration of oxygen not only increases the conversion of propane, but also affects the ratio of the reaction products. The yield of ethylene and propylene was found to depend on the initial propane to oxygen ratio and reaction temperature.

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Section: Results Of Experimentsmentioning

confidence: 92%

Effect of oxygen concentration on the oxidative conversion of propane

Pogosyan

Arsentiev

et al. 2015

Russ. J. Phys. Chem. B

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“…This makes it possible to perform the selective gas phase oxidation of C 3 + alkanes in complex mixtures of hydrocarbon gases, such as natural and associated gas, practically without involving methane into the oxidation process. Moreover, the methane content even increases, since it is one of the main products of oxycracking of its heavier homologues [11,14,20]. The main products of the oxycracking of methane homologues are ethylene, methane, ethane, hydrogen, and carbon monoxide, with ethane and propylene being present in small amounts [17,[20][21][22].…”

Section: Selective Oxycracking Of Heavier Components Of Natural Gasmentioning

confidence: 99%

“…Moreover, the methane content even increases, since it is one of the main products of oxycracking of its heavier homologues [11,14,20]. The main products of the oxycracking of methane homologues are ethylene, methane, ethane, hydrogen, and carbon monoxide, with ethane and propylene being present in small amounts [17,[20][21][22]. The presence of a heterogeneous catalyst significantly accelerates the process at low temperatures, but impedes it at higher temperatures, at which an abrupt transition to the branched-chain-reaction mode occurs.…”

Section: Selective Oxycracking Of Heavier Components Of Natural Gasmentioning

confidence: 99%

Partial Oxidation of Light Alkanes as a Base of New Generation of Gas Chemical Processes

2013

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Recent developments in unconventional natural gas production increase the need for principally new small-scale technologies for gas processing and transportation. The promising way for small-scale gas processing is its autothermal partial oxidation to syngas or direct partial oxidation to chemicals. The paper considers some prospective gas chemical processes based on the partial oxidation of light alkanes. Among them are the conversion of natural gas to syngas in volumetric (3D) matrix burners made of a gas permeable material and direct conversion of methane to methanol without its preliminary conversion to syngas (DMTM). As a more simple technology that lets to use fat associated oil gas often flaring in remote sites, it can be suggested the selective oxidative cracking of heavier components of natural gas. This process converts heavy methane homologues from propane to pentane and heavier into ethylene, methane, ethane, hydrogen, and carbon monoxide, thus increasing methane index (octane number) of gas and making it suitable for feeding modern gas piston and gas turbine power engines. One more interesting prospect is the creation of technologies making use of the subsequent processing of valuable oxycracking products, such as olefins, CO, and hydrogen, for example, by their catalytic co-polymerization without preliminary separation from gas phase. The co-polymerization of CO and ethylene, followed by the separation of resulting liquid products, can considerably improve the economic attractiveness of the oxycracing process. Thus, despite the absence of economically proved and industrial-scale tested smallcapacity direct and indirect gas chemical technologies, intensive efforts to develop such alternative technologies let to expect near bright future for them.

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“…The use of an oxidant in the dehy drogenation of lower alkanes has a number of potential benefits: it improves the performance of the pyrolysis process, allows bypassing the restrictions imposed by thermodynamics on the product composition and conducting the process at lower temperatures due to the exothermic oxidation reactions directly in the reaction zone, and increases the catalyst on stream time owing to possible coke burn up during the reac tion [2,3].…”

mentioning

confidence: 99%

“…Reaction (1) is favored at T ≥ 500°C, whereas reaction (2) proceeds at any temperature in the temperature range examined. The heat of reaction (2) can be used to compensate for the energy consumed for heating the reaction medium. Analysis of the data in Table 1 shows that the oxidative thermal degradation of ethane is more pref erable than the direct degradation reaction in terms of both energy characteristics and purity of the products.…”

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confidence: 99%

Thermodynamic and quantum-chemical study of the oxidative dehydrogenation of ethane to ethylene

et al. 2015

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A major amount of ethylene in the industry is cur rently produced by the pyrolysis of hydrocarbon feed stock (ethane, ethane-propane-butane mixture, or straight run gasoline fraction) in a tubular furnace. The yield of olefins (ethylene + propylene) is 60-66%. The development of the process is focused on improving the existing technology. However, despite the progress associated with changes in the arrange ment of the radiant coil pipes in the furnace, the designing of effective transfer line exchangers, and the introduction of furnaces with a short residence time of feedstock in the reaction zone, the potentialities of this process are limited, especially in the case of feed stock prone to enhanced coking [1]. The necessity to expand the resource base, in particular, involvement of the components of natural, associated, and refinery gases in processing requires searching for fundamen tally new methods of implementation of the process.Thus, since the middle of the last century, intensive studies are conducted on the development of processes for catalytic dehydrogenation of lower alkanes to the corresponding olefins. Use of a catalyst makes it pos sible to increase the feedstock conversion as compared with the conventional pyrolysis process and improve the process selectivity. However, from the viewpoint of practical application, this dehydrogenation process also has drawbacks associated in particular with intense coking and the need to conduct oxidative regeneration.These drawbacks are eliminated by using an oxi dant in the process. The use of an oxidant in the dehy drogenation of lower alkanes has a number of potential benefits: it improves the performance of the pyrolysis process, allows bypassing the restrictions imposed by thermodynamics on the product composition and conducting the process at lower temperatures due to the exothermic oxidation reactions directly in the reaction zone, and increases the catalyst on stream time owing to possible coke burn up during the reac tion [2,3].In view that this line of research holds enough promise, we performed comparative thermodynamic calculation of the equilibrium product composition for thermal and oxidative dehydrogenations of ethane and quantum chemical calculation of the activation energy of ethane dehydrogenation in the active metal phase of the catalyst molybdenum oxide МоО 2 .The equilibrium concentrations of the reaction components were calculated in the ideal gas approxi mation [4, 5]. Table 1 shows values for the thermody namic functions enthalpy ΔH, entropy ΔS, and Gibbs free energy ΔG of the two simple reactions:These reactions are interesting in that hydrogen and water are produced in reactions (1) and (2), respectively. Naturally, the second reaction is preferred from the standpoint of obtaining pure ethylene.As can be seen from Table 1, these reactions signif icantly differ in thermodynamic characteristics. Enthalpy ΔH slightly depends on temperature, reac tion (1) is strongly endothermic, and reaction of (2) is exothermic. Gibbs energies ΔG of the rea...

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Gas-phase oxypyrolysis of light alkanes

Cited by 33 publications

References 15 publications

Effect of oxygen concentration on the oxidative conversion of propane

Effect of oxygen concentration on the oxidative conversion of propane

Partial Oxidation of Light Alkanes as a Base of New Generation of Gas Chemical Processes

Thermodynamic and quantum-chemical study of the oxidative dehydrogenation of ethane to ethylene

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