Pyridine hydrodenitrogenation over industrial NiMo/γ-Al2O3 catalyst: Application of gas phase kinetic models to liquid phase reactions

Raghuveer, Chetan Shreedhar; Thybaut, Joris W.; Bruycker, Ruben De; Metaxas, Konstantinos; Bera, Tapan; Marin, Guy

doi:10.1016/j.fuel.2014.02.017

Cited by 26 publications

(16 citation statements)

References 68 publications

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“…42 Table 5 lists the experimental inhibition constants reported by La Vopa and Satterfield 39 and Nagai et al 40 The order of magnitude of these numbers are close to each other although Nagai et al reports values for inhibition of hydrogenation of dibenzothiophene; the value reported by Egorova and Prins 42 for inhibition of dibenzothiophene HDS by 2-methyl pyridine (0.53 kPa 21 ) and that estimated by Raghuveer et al 61 through kinetic modeling of pyridine HDN (61 atm 21 ) is also consistent with pyridine values shown in Table 5 (noting that single methyl substitution does not lead to steric hindrance in pyridine based on our calculations). However, these values are two orders of magnitude smaller than that reported by Beltramone et al 60 ; the origin of these differences is unclear.…”

Section: Inhibition Constants: Experiments Vs Theorymentioning

confidence: 62%

Adsorption of nitrogen‐ and sulfur‐containing compounds on NiMoS for hydrotreating reactions: A DFT and vdW‐corrected study

Rangarajan

Mavrikakis

2015

AIChE Journal

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Adsorption of 35 molecules, comprising of organonitrogen and organosulfur compounds and hydrocarbons relevant to hydrotreating, was studied on the nickel-promoted metal edge of molybdenum sulfide catalysts using periodic DFT, accounting for van der Waals interactions in several cases. Basic molecules tend to adsorb via their nitrogen atoms directly on top of nickel atoms while nonbasic molecules adsorb via carbon atoms relatively weakly. Molecular size, electron density, and alkyl substitution affects binding at the GGA-PW91 level of theory. van der Waals corrections influence adsorption geometry and lead to significant additional stabilization of adsorbates. The differential binding energy of nitrogen-containing compounds decreases by 0.2-0.3 eV for each additional molecule added on the edge and their presence destabilizes the binding of organosulfur compounds by more than 0.2 eV. The inhibition of hydrodesulfurization is suggested to arise from site blocking and destabilization of reaction intermediates and transition states by organonitrogen compounds. V C 2015 American Institute of Chemical Engineers AIChE J, 61: [4036][4037][4038][4039][4040][4041][4042][4043][4044][4045][4046][4047][4048][4049][4050] 2015

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Section: Inhibition Constants: Experiments Vs Theorymentioning

confidence: 62%

Adsorption of nitrogen‐ and sulfur‐containing compounds on NiMoS for hydrotreating reactions: A DFT and vdW‐corrected study

Rangarajan

Mavrikakis

2015

AIChE Journal

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“…This fundamental character of the model guarantees adequate extension from gas phase purecomponent alkane data towards more industrially relevant conditions such as (complex) mixtures under liquid-phase conditions. [16][17][18] The present work demonstrates how physisorption and phase effects can significantly conceal intrinsic reaction kinetics in hydroconversion. The synergy between a shape-selective and a non-shape selective zeolite is further explored for an n-alkane mixture under liquid-phase conditions via SEMK model simulations.…”

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confidence: 67%

“…Parapur is an adequate model feed for a Fischer-Tropsch wax primarily composed of n-alkanes which require a post-processing step to convert them into high-quality fuel blends. 24,25 By virtue of the SEMK methodology, the gap between gas-and liquidphase conversion can be adequately bridged, which 17,18 consequently opens up the route towards SEMK-based screening of advanced catalytic materials under virtually any set of reaction conditions. The acquisition itself of intrinsic kinetic data under liquid bulk phase conditions and total feed conversions exceeding 90% remains a challenging task due to, e.g., catalyst deactivation via coking.…”

mentioning

confidence: 99%

“…26 Gas-to-liquid phase kinetic simulations have been proven however to provide an adequate representation of liquid-phase kinetic performance starting from gas phase data. 16,18 SEMK simulation studies were carried out considering a 75-25, a 50-50 and a 25-75 wt% Y-ZSM22 mixture, in addition to the pure catalysts. ZSM22 and Y zeolites identical to those applied in the work of Choudhury et al 15 were considered.…”

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confidence: 99%

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Maximizing n-alkane hydroisomerization: the interplay of phase, feed complexity and zeolite catalyst mixing

Vandegehuchte

Thybaut

Martens

et al. 2015

Catal. Sci. Technol.

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Mixing of zeolites with different pore sizes enhances the yield of skeletal isomers from pure n-alkanes, but this synergic effect is limited in n-alkane mixtures because of preferential adsorption and cracking of the longest molecules. Single-Event MicroKinetic (SEMK) analysis reveals that enhanced yields of skeletal isomers can be obtained even with n-alkane mixtures, provided that the hydroisomerization reaction is performed under liquid-phase reaction conditions. Skeletal isomerization of linear alkanes is an essential process of fossil and renewable hydrocarbon fuel and lubricant production. The SEMK model enables the selection of optimum catalyst formulation and reaction conditions for superior paraffinic wax hydroconversion.Current trends in fuel quality regulations prompt more advanced production processes for environmentally benign diesel and gasoline fuels exhibiting desired (ignition) properties. Medium-pore zeolites containing a one-dimensional pore structure, such as TON, MTT and AEL, have been established as ideal n-alkane hydroisomerization catalysts giving rise to 15-20% enhancement of the maximum isomer yield compared to non-shape selective catalysts. 1,2 The latter was rationalized in terms of the suppression of multibranched feed isomer formation at the pore mouths, while the active sites inside the pores remain exclusively accessible to linear alkanes. 3,4 Such shape-selective phenomena were denoted as 'pore mouth' and 'key lock' catalysis by Martens and co-workers, 5,6 who thoroughly investigated the product distributions obtained from heavy alkane hydroconversion on Pt/H-ZSM22. Although contested by a few other authors, 7,8 the establishment of pore mouth and key lock catalysis during n-alkane hydroconversion on unidirectional 10-membered pore zeolites was supported by separate physisorption measurements. 9,10 The elimination of micropore acid sites, accessible only to linear alkanes, was found crucial in optimizing the isomer selectivity of the catalyst, as elaborated from various synthesis studies. 11,12 A further increase in maximum isomer yield could be achieved by physically mixing a ZSM22 (Si/Al = 45) zeolite with a non-shape selective Y (Si/Al = 2.6) zeolite, both loaded with 0.5 wt% Pt. 13 The observed synergy was explained through primary monobranching on the more active ZSM22, followed by secondary dibranched isomer formation on the more mildly active Y. The corresponding energy profiles are schematically represented in Fig. 1. Herein, the only relevant cracking mode on ZSM22, which is (s;p) β-scission of n-alkanes towards an unstable primary ion inside the micropores, is not shown. The pathway with the least resistance, i.e., the lowest activation energies, is followed. As evident from the profile corresponding to the catalyst mixture depicted on the right, multibranching occurs exclusively on the Y zeolite after primary monobranching on ZSM22. This Catal. Sci. Technol. This journal is

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“…As a result, it is necessary to implement new catalyst systems that offer improved activity and selectivity for HDN. Therefore, in order to study HDN, different model molecules have been used [11][12][13][14] , one of which is pyridine [15][16][17] . Valdebenito et al 17 worked with stacked bed systems in the HDN of pyridine, proving that it is possible to achieve this process through the formation of hydrogen spillover (Hso), generating an effect similar to that observed for the HDS reaction [18][19][20][21][22][23] .…”

Section: Introductionmentioning

confidence: 99%

Tungsten and Rhenium as Hydrogenation Agents in the Hydrodenitrogenation of Pyridine Using Stacked Bed Catalyst Systems

Bassi

Villarroel

Llambías

et al. 2015

J. Chil. Chem. Soc.

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This study analyses the hydrodenitrogenation (HDN) of pyridine using a stacked bed catalyst system, composed of a first hydrogenating bed of Re/γ-Al 2 O 3 or W/γ-Al 2 O 3 , over a second bed of Ni-Re/γ-Al 2 O 3 (HDN bed). Using potentiometric methods, it can be seen that the Re/γ-Al 2 O 3 shows higher acidic strength than the W/γ-Al 2 O 3 . The results show that higher activity levels are obtained working with stacked bed systems compared to the separate catalysts. These results suggest that the incorporation of the catalyst Re/γ-Al 2 O 3 or W/γ-Al 2 O 3 beds would favour the formation of hydrogenated intermediary products, facilitating the removal of N-containing molecules via HDN on the Ni-Re/γ-Al 2 O 3 catalyst.

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Pyridine hydrodenitrogenation over industrial NiMo/γ-Al2O3 catalyst: Application of gas phase kinetic models to liquid phase reactions

Cited by 26 publications

References 68 publications

Adsorption of nitrogen‐ and sulfur‐containing compounds on NiMoS for hydrotreating reactions: A DFT and vdW‐corrected study

Adsorption of nitrogen‐ and sulfur‐containing compounds on NiMoS for hydrotreating reactions: A DFT and vdW‐corrected study

Maximizing n-alkane hydroisomerization: the interplay of phase, feed complexity and zeolite catalyst mixing

Tungsten and Rhenium as Hydrogenation Agents in the Hydrodenitrogenation of Pyridine Using Stacked Bed Catalyst Systems

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