Hydrocracking of long chain linear paraffins

Rossetti, Ilenia; Gambaro, Chiara; Calemma, Vincenzo

doi:10.1016/j.cej.2009.03.018

Cited by 60 publications

(39 citation statements)

References 42 publications

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“…The latter typically consist of long normal alkanes which is limiting their use as fuel or lubricant. The resulting hydrocracking products are characterized by high cetane numbers, attractive emission properties and improved cold-flow properties [4,5].…”

Section: Introductionmentioning

confidence: 99%

n-Hexadecane hydrocracking Single-Event MicroKinetics on Pt/H-beta

Vandegehuchte

Thybaut

Martı́nez

et al. 2012

Applied Catalysis A: General

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The Single-Event MicroKinetic (SEMK) model constructed for gas-phase hydroconversion of light n-alkanes on large-pore USY zeolites was applied, for the first time, to the hydrocracking of n-hexadecane on a Pt/H-Beta catalyst. Despite the 12-ringed pore channels, shape selectivity was observed in the formation of ethyl side chains.Additionally, heavy feed molecules such as n-hexadecane lead to physisorption saturation of the catalyst pores by strong Van der Waals interactions of the long alkyl chains with the zeolite framework. Intermolecular interactions and packing efficiencies in the pores induce deviations from typical Henry-regime physisorption characteristics as the physisorption selectivity, which is expected to increase with increasing carbon number, appeared to be independent of the latter. Micropore saturation effects were described by the 'size entropy' which quantifies the difference in standard entropy loss between physisorption in the Henry regime and hindered physisorption on a saturated surface. The size entropy is proportional to the catalyst loading with physisorbed species and the adsorbate carbon number. The addition of a size entropy term in the SEMK model, amounting to 102 J mol -1 K -1 for a hexadecane molecule at full saturation, allowed accurately reproducing the contribution of secondary isomerization and cracking reactions, as quantified by means of a contribution analysis.2

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Section: Introductionmentioning

confidence: 99%

n-Hexadecane hydrocracking Single-Event MicroKinetics on Pt/H-beta

Vandegehuchte

Thybaut

Martı́nez

et al. 2012

Applied Catalysis A: General

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“…5,6,11 This was explained by considering that for light paraffins, the concentration of carbenium ions is negligible with respect to the overall number of active sites. 11 However, recent results suggest that with relatively long-chain paraffins (n-C 16 H 34 and n-C 28 H 58 , 29 ), the term 30 observing fractional reaction orders for both H 2 and n-hexane during hydroisomerization of the paraffin on Pt/zeolites. Thus, the contribution of the paraffin concentration is not negligible with respect to the H 2 concentration.…”

Section: Modelmentioning

confidence: 93%

Hydrocracking of Fischer‐Tropsch waxes: Kinetic modeling via LHHW approach

et al. 2011

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A lumped kinetic model to describe the hydrocracking of complex mixtures of paraffins, such as Fischer-Tropsch waxes, has been developed. A Langmuir-HinshelwoodHougen-Watson approach has been followed, accounting for physisorption by means of the Langmuir isotherm. Finally, a complete form of the rate expression is used, thus introducing the equilibrium constants for dehydrogenation and protonation elementary steps. To minimize the number of model parameters, the kinetic and thermodynamic constants are defined as functions of the chain length. Vapor-liquid equilibrium is calculated along the reactor, and the hydrocarbons concentrations are described by means of fugacity. The model provides quite a good fitting of experimental results and is able to predict the effects of the operating conditions (temperature, pressure, H 2 / wax ratio, and WHSV). Outstandingly, the estimated values and trends of the kinetic and thermodynamic constants (activation energies, Langmuir adsorption constants, etc.) are in line with their physical meaning.

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“…As an example, the melting point of hexadecane is 19°C, making it impossible to use since the specification for gasoil is -15°C. Now, the hydroisomerization reaction of heavy linear alkanes allows to decrease significantly the melting point of paraffinic compounds while leaving unchanged their molecular weight -the melting point of 5-methylpentadecane is -31°C [1][2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Effect of Na exchange of a HBEA zeolite on the activity and the selectivity of a bifunctional Pt-HBEA catalyst for n-hexadecane hydroisomerization. Comparison with a Pt-HZSM-22 catalyst

Merabti

Pinard

Lemberton

et al. 2010

Reac Kinet Mech Cat

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The transformation of n-hexadecane was carried out in a fixed-bed reactor at 220°C under 30 bar total pressure on bifunctional Pt-zeolite catalysts. The Pt-HBEA catalyst was very active but yielded much cracked products due to a rather strong protonic acidity. Pt-Na-HBEA catalysts obtained through partial exchange by sodium ions of the protonic sites of the HBEA zeolite were less active than Pt-HBEA but allowed to decrease significantly cracking. The effect of Na exchange on the activity of the catalysts was quantified using a kinetic model. Pt-HZSM-22 was much less active than Pt-HBEA but more selective for isomerization. However, the selectivity for isomerization of the Pt-Na-HBEA was very similar to that of Pt-HZSM-22 up to a 80% n-hexadecane conversion, while its activity was 2.5 times higher.

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Hydrocracking of long chain linear paraffins

Cited by 60 publications

References 42 publications

n-Hexadecane hydrocracking Single-Event MicroKinetics on Pt/H-beta

n-Hexadecane hydrocracking Single-Event MicroKinetics on Pt/H-beta

Hydrocracking of Fischer‐Tropsch waxes: Kinetic modeling via LHHW approach

Effect of Na exchange of a HBEA zeolite on the activity and the selectivity of a bifunctional Pt-HBEA catalyst for n-hexadecane hydroisomerization. Comparison with a Pt-HZSM-22 catalyst

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