Reforming alkanes

Fig. 5. Thermodynamic EMF of an in situ reformed alkane cell versus carbon atom number in the alkane molecule. From ref. [10].

Since reforming alkanes larger than CH, involves the breaking of the C-C bonds, avoiding the formation of C filaments becomes more challenging. 

Butanes are naturally occurring alkane hydrocarbons that are produced primarily in association with natural gas processing and certain refinery operations such as catalytic cracking and catalytic reforming. The term butanes includes the two stmctural isomers, / -butane [106-97-8] CH2CH2CH2CH2, and isobutane [79-28-9], (CH2)2CHCH2 (2-methylpropane). 

Reforming is the conversion primarily of naphthenes and alkanes to aromatics, but other reactions also occur under commercial conditions. Platinum or platinum/rhenium are the hydrogenation/ dehydrogenation component of the catalyst and alumina is the acid component responsible for skeletal rearrangements. 

Fired reactors contain tubes or coils in which an endothermic reaction within a stream of reac tants occurs. Examples include steam/ hydrocarbon reformers, catalvst-filled tubes in a combustion chamber pyrolyzers, coils in which alkanes (from ethane to gas oil) are cracked to olefins in both types of reac tor the temperature is maintained up to 1172 K (1650°F). 

Alkanes and Alkenes. For this study, C150-1-01 and C150-1-03 were tested under primary wet gas conditions with ethylene, ethane, propylene, and propane being added to the feed gas. This study was made in order to determine whether these hydrocarbons would deposit carbon on the catalyst, would reform, or would pass through without reaction. The test was conducted using the dual-reactor heat sink unit with a water pump and vaporizer as the source of steam. All gas analyses were performed by gas chromatography. The test was stopped with the poisons still in the feed gas in order to preserve any carbon buildup which may have occurred on the catalysts. 

Catalytic reformers take linear alkanes, e.g., -pentane, and produce branched alkanes, e.g., i-pentane. The catalyst is finely divided platinum on Si203. 

Hydrogenolysis of butane was used to study the catalysis of the RhPt particles in mesoporous silica. This is a test reaction of reforming of alkanes in oil refinery, and methane, ethane, and propane are formed by the cleavage of terminal or central C-C bond (Scheme 1). 

However, some contradictory results were obtained in several studies. For instance, in the CH4-NO reaction, some authors have reported that N20 was the primary product [95] while others found that ammonia was first produced [96], The presence of water can play a decisive role since H20 allows generating H2 by WGS or steam reforming [59], Olefins generally show a higher activity than alkanes. Propene for instance has been found more reactive than propane. Some exceptions should be quoted, ethylene has been found less reactive than CH4 in NO reduction at stoichiometry [97],... 

Davda, R. R. Shabaker, J. W. Huber, G. W. Cortright, R. D. Dumesic, J. A., A review of catalytic issues and process conditions for renewable hydrogen and alkanes by aqueous-phase reforming of oxygenated hydrocarbons over supported metal catalysts. Applied Catalysis B 2005,56,171. 

In hydrocarbon reforming processes the vapour of an alkane is passed over a supported metal catalyst such as platinum on silica or alumina. Dehydrocyclization, isomerization and cracking reactions all take place to... 

Catalytic dehydrocyclization (also known as alkane reforming), discovered in 1936, is now an important industrial process that converts alkanes to aromatics (1, 2). This reaction is often shown for the prototypic conversion of heptane to toluene and four moles of hydrogen, although in model studies octanes have played a greater role since there is a larger product diversity possible. 

Dumesic has reviewed the aqueous-phase reforming of polyols to H2 and CO2 under milder conditions, i.e., 200-250 °C [43], He also showed the possibility to divert the reaction towards to production of alkanes by using an acidic support for the Pt or Pd reforming catalyst. 

The modem gasolines are produced by blending products from cmde oil distillation, that is, fluid catalytic cracking, hydrocraking, reforming, coking, polymerization, isomerization, and alkylation.Two clear examples of the possible use of solid-acid catalysts in refining processes are the isomerization of lineal alkanes and the alkylation of isobutene with butanes. In both these cases, and due to the octane... 

The activation of alkanes on transition metal surfaces is an important step in many catalytic reactions. Hydrogenolysis, steam reforming and isomerization of alkanes all involve alkane dissodation. Thus, much interest exists in the mechanistic and kinetic aspects of alkane dissociation. 

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