Competitive Adsorption of C20−C36 Linear Paraffins on the Amorphous Microporous Silica−Alumina ERS-8 in Vapor Phase and Liquid Phase

Li, Ben; Calemma, Vincenzo; Gambaro, Chiara; Baron, Gino V.; Denayer, Joeri

doi:10.1021/ie100728h

Cited by 11 publications

(22 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similar saturation effects were observed during gas-phase physisorption experiments on a faujasite with nC 16 as pure feed component and at similar operating conditions [57]. Intermolecular interactions arise at near-saturation loadings and affect the physisorption behaviour of the individual components in such a way that the physisorption selectivity observed at lower loadings, gradually disappears and, ultimately, even may invert [28,29,[59][60][61]. However, such an isotherm is empirical in nature and the estimated interaction parameters have no explicit physical meaning.…”

Section: Development Of a Physisorption Model Accounting For Micropormentioning

confidence: 67%

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

Vandegehuchte

Thybaut

Martı́nez

et al. 2012

Applied Catalysis A: General

View full text Add to dashboard Cite

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

show abstract

Section: Development Of a Physisorption Model Accounting For Micropormentioning

confidence: 67%

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

Vandegehuchte

Thybaut

Martı́nez

et al. 2012

Applied Catalysis A: General

View full text Add to dashboard Cite

show abstract

“…A decrease in the iso/paraffin ratio with carbon number after the peak value could be due to a spatial effect for the isomerization of large molecules. However, the isoparaffin content kept increasing with increasing carbon number on the N 2 -activated NiMo catalyst, and this could be due to (1) an enhanced BAS density on the catalyst; (2) the adsorption energy is increased with increasing chain length [3,46]; (3) heavier hydrocarbons were present mainly in the liquid phase under the reaction conditions, thus resulting in longer chain-length dependent residence times in the catalyst bed, and/or (4) large pore Al 2 O 3 supports benefit isomerization. These factors could enhance the isomerization of higher molecular weight hydrocarbons.…”

Section: Isoparaffin Content Versus Carbon Numbermentioning

confidence: 99%

Hydrocracking of Octacosane and Cobalt Fischer–Tropsch Wax over Nonsulfided NiMo and Pt-Based Catalysts

Kang

Jacobs

et al. 2021

Reactions

View full text Add to dashboard Cite

The effect of activation environment (N2, H2 and H2S/H2) on the hydrocracking performance of a NiMo/Al catalyst was studied at 380 °C and 3.5 MPa using octacosane (C28). The catalyst physical structure and acidity were characterized by BET, XRD, SEM-EDX and FTIR techniques. The N2 activation generated more active nonsulfided NiMo/Al catalyst relative to the H2 or H2S activation (XC28, 70–80% versus 6–10%). For a comparison, a NiMo/Si-Al catalyst was also tested after normal H2 activation and showed higher activity at the same process conditions (XC28, 81–99%). The high activity of the NiMo/Al (N2 activation) and NiMo/Si-Al catalysts was mainly ascribed to a higher number of Brønsted acid sites (BAS) on the catalysts. The hydrocracking of cobalt wax using Pt/Si-Al and Pt/Al catalysts confirmed the superior activity of the Si-Al support. A double-peak product distribution occurred at C4–C6 and C10–C16 on all catalysts, which illustrates secondary hydrocracking and faster hydrocracking at the middle of the chain. The nonsulfided NiMo/Al and Pt/Al catalysts, and NiMo/Si-Al catalyst produced predominantly diesel (sel. 50–70%) and gasoline range (sel. > 50%) hydrocarbons, respectively, accompanied by some CH4 and light hydrocarbons C2–C4. On the other hand, the hydrocarbon distribution of the Pt/Si-Al varied with conditions (i.e., diesel sel. 87–90% below 290 °C or gasoline sel. 60–70% above 290 °C accompanied by little CH4) The dependence of the isomer/paraffin ratio on chain length was studied as well. The peak iso/paraffin value was observed at C10–C13 for the SiAl catalyst.

show abstract

“…The rates of B1- and B2-type cracking are related to that of type A, using factors derived from experimental data . Isomerization and cracking reactions are assumed to have equal activation energies. , Adsorption on acid sites is considered to be invariant, with respect to paraffin chain length, as suggested by experimental evidence, , and therefore is represented by a single fitting coefficient. Paraffin isomerization equilibrium coefficients are estimated using Benson’s group contribution method.…”

Section: Modeling Approachmentioning

confidence: 99%

Stochastic Modeling and Simulation Approach for Industrial Fixed-Bed Hydrocrackers

Alvarez‐Majmutov

Chen

2017

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

In this study, we developed a comprehensive model to simulate vacuum gas oil (VGO) hydrocracking. The model incorporates knowledge of feedstock composition and reaction chemistry at the molecular level and is tuned with pilot plant data. The molecular makeup of the feedstock is derived from its analytical characterization via statistical modeling. Hydrocracking reactivity is described based on the molecular structure of the reactants. Progression of chemical reactions is simulated using a kinetic Monte Carlo algorithm. A stochastic heat balance equation is integrated into the model to represent adiabatic operation. Vapor–liquid equilibrium (VLE) calculations are executed in parallel with an in-house flash program. Hydrocracker simulations were conducted covering the typical range of conversion levels observed in commercial operation. The model generates detailed information on product distribution as well as product quality. In addition, the model is able to track the evolution of hydrogen consumption, hydrocarbon vaporization, and temperature along the reactor.

show abstract

Competitive Adsorption of C20−C36 Linear Paraffins on the Amorphous Microporous Silica−Alumina ERS-8 in Vapor Phase and Liquid Phase

Cited by 11 publications

References 36 publications

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

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

Hydrocracking of Octacosane and Cobalt Fischer–Tropsch Wax over Nonsulfided NiMo and Pt-Based Catalysts

Stochastic Modeling and Simulation Approach for Industrial Fixed-Bed Hydrocrackers

Contact Info

Product

Resources

About