Hydrocracking of vacuum gas oil over NiMo/Y-Al2O3: Effect of mesoporosity introduced by zeolite Y recrystallization

Казаков, М. О.; Надеина, К.А.; Данилова, И. Г.; Дик, П. П.; Климов, О. В.; Pereyma, V. Yu.; Gerasimov, E. Yu.; Dobryakova, I. V.; Knyazeva, E. E.; Иванова, И. И.; Носков, А. С.

doi:10.1016/j.cattod.2017.08.048

Cited by 54 publications

(37 citation statements)

References 52 publications

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“…In order to improve transport properties of zeolite crystals mesopores can be created. [1][2][3][4][5][6][7][8][9][10] In 2005, an attractive procedure was proposed consisting of the transformation of a silica-rich FAU-Y into mesoporous FAU-Y by a post-treatment in an alkaline solution containing alkyltrimethylammonium bromide surfactants (CnTAB). This created homogeneous ordered mesopores as in MCM-41 materials inside the FAU-Y crystals.…”

Section: Surface Areas Of Mechanical Mixtures Of Fau-mentioning

confidence: 99%

Specific Surface Area Determination for Microporous/Mesoporous Materials: The Case of Mesoporous FAU-Y Zeolites

et al. 2018

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Rouquerol criterion and the BET equation is in accord with the geometrical surface determined by the chord length distribution method. Therefore BET surface area (S BET) is well representative of micropore surface areas of microporous materials and of total surface area of microporous/mesoporous materials. Mechanical mixtures of mesoporous MCM-41 and microporous FAU-Y powders of known surface areas were used to calculate the respective surface areas by weighted linear combination and the results were compared to the values obtained by the t-plot method. The first slope of the t-plot determined the mesopore + external surface areas (S mes+ext). The linear fit of the first slope is in general in the range 0.01 < p/p 0 < 0.17 and contains the volumes and relative pressures at which all micropores are filled (p/p 0 > 0.10). Overestimation of S mes+ext values was evident and appropriate corrections were provided. External surface areas (S ext) were obtained from the second slope of the t-plot, without noting an overestimation of S ext , thus allowing the determination of mesopore surface areas (S mes) by difference. Micropore surface areas were calculated by subtracting S mes+ext from the total surface area, S BET. As an example, this methodology was applied to the characterization a family of hierarchical microporous/mesoporous FAU-Y (FAUmes) synthesized from H-FAU-Y (H-Y, Si/Al = 15) using C18TAB as surfactant and different NaOH/Si ratio (0.05 < NaOH/Si < 0.25). By increasing the NaOH/Si ratio in synthesis of FAUmes, it was shown that as the micropore surface area decreases, the mesopore surface area increases, while the micropore + mesopore surface area remains constant. This methodology allows accurate characterization of the surface areas of microporous/mesoporous materials.

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Section: Surface Areas Of Mechanical Mixtures Of Fau-mentioning

confidence: 99%

Specific Surface Area Determination for Microporous/Mesoporous Materials: The Case of Mesoporous FAU-Y Zeolites

et al. 2018

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“…Under appropriate conditions, good agreement between Brönsted acidity determined by FTIR of adsorbed Pyridine, n-hexane cracking and the area of the high temperature peak of NH 3 TPD has been observed for zeolites (BEA), with a slightly lower amount of strong acidity found by NH 3 TPD. 38 Acidity characterization of FAUmes materials using cetyltrimethylammonium as surfactant and NH 4 OH as basic medium (FAUmes(C16)) has been reported recently 4 and revealed a good agreement between the relative amount of strong acidity determined by NH 3 TPD (peak centered at 380-390 °C), the relative amount of strong Brönsted acidity determined by CO adsorption followed by FTIR and by the area of the FTIR Si-O(H)-Al supercage signal at 3630 cm -1 .…”

Section: Textural Properties Of Faumes Determined By Geometrical Methmentioning

confidence: 99%

“…To increase the accessibility of the reactants to the active sites as well as the desorption of the products, creation of additional mesopores in zeolite crystals has been proposed. [2][3][4][5][6][7][8][9][10] Most commonly, zeolites can be dealuminated to create large pores in the crystals, but these pores are inhomogeneous in size, often not directly connected to the exterior of the crystal and not forming a connected network inducing very low increase in diffusion, as usually assumed in the literature. 11 Additional techniques have been used to further increase diffusion in zeolites such as desilication in basic medium leading to mesopores connected to the exterior but inhomogeneous in size.…”

Section: Introductionmentioning

confidence: 99%

“…22 Different experimental conditions have been reported in the literature for the synthesis of FAUmes starting from zeolite crystals with various Si/Al ratios, using several sources of alkali (NaOH, TMAOH, NH 4 OH), different temperatures (80, 115, 150 °C), different durations (12 to 24 h) and different types and amounts of alkyltrimethylammonium surfactants (CnTAX, n = 10 -22, X = Cl, Br). 4,[14][15][16][17][18][19][20][21][22][23][24] In the present study, a systematic investigation of the materials resulting from the transformation of FAU-Y (Si/Al = 15) into FAUmes has been performed. Materials have been prepared using C18TAB as surfactant and NaOH as the alkali from mixtures with molar ratios 1 SiO 2 / n NaOH / 0.1 C18TAB / H O (n = 0.025 -0.25) at 115 °C for h. Our aim was to analyze precisely their structural, textural and acidic properties as a function of NaOH/Si ratio.…”

Section: Introductionmentioning

confidence: 99%

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Revelation on the Complex Nature of Mesoporous Hierarchical FAU-Y Zeolites

et al. 2018

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The texture of mesoporous FAU-Y (FAUmes) prepared by surfactant-templating in basic media is a subject of debate. It is proposed that mesoporous FAU-Y consists of: (1) ordered mesoporous zeolite networks formed by a surfactant-assisted zeolite rearrangement process involving local dissolution and reconstruction of the crystalline framework, and (2) ordered mesoporous amorphous phases as Al-MCM-41, which coexist with zeolite nanodomains obtained by a dissolution-reassembly process. By the present systematic study, performed with FAU-Y (Si/Al = 15) in the presence of octadecyltrimethylammonium bromide and 0 < NaOH/Si ratio < 0.25 at 115 °C for 20 h, we demonstrate that mesoporous FAU zeolites consist, in fact, of a complex family of materials with textural features strongly impacted by the experimental conditions. Two main families have been disclosed: (1) for 0.0625 < NaOH/Si < 0.10, FAUmes are ordered mesoporous materials with zeolite walls, which coexist with zeolite nanodomains (100-200 nm) and (2) for 0.125 < NaOH/Si < 0.25, FAUmes are ordered mesoporous materials with amorphous walls as Al-MCM-41, which coexist with zeolite nanodomains (5-100 nm). The zeolite nanodomains decrease in size with the increase of NaOH/Si ratio. Increasing NaOH/Si ratio leads to an increase of mesopore volume, while the total surface area remains constant, and to a decrease of strong acidity in line with the decrease of micropore volume. The ordered mesoporous materials with zeolite walls feature the highest acidity strength. The ordered mesoporous materials with amorphous walls present additional large pores (50-200 nm), which increase in size and amount with the increase of NaOH/Si ratio. This alkaline treatment of FAU-Y represents a way to obtain ordered mesoporous materials with zeolite walls with high mesopore volume for NaOH/Si = 0.10 and a new way to synthesize mesoporous Al-MCM-41 materials containing extralarge pores (50-200 nm) ideal for optimal diffusion (NaOH/Si = 0.25).

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“…Similarly, the processes are mainly applied at laboratory scale as model studies, which does not necessarily provide an industrial replica [12]. At present, most commercial hydrocracking zeolitic catalysts are based on ultrastable Y zeolites (USY) [31]. In our previous study [32], a synthesis method of hierarchical Beta zeolite using a soft-template CTAB, which is available commercially, was developed.…”

Section: Introductionmentioning

confidence: 99%

Practical Application of Hierarchical Beta Zeolite in a Vacuum Gas Oil Hydrocracking Catalyst

Zhang

Qin

et al. 2020

Chem Eng & Technol

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A hierarchical Beta zeolite has been successfully mass-prepared hydrothermally and dynamically in a pilot-scale autoclave by an economical and simple process with low-cost raw materials. The characterization results indicated that the pilotscale hierarchical Beta zeolite has the same textural, structural, and acidic properties like the bench-scale sample. Moreover, the catalyst composed of the pilot-scale hierarchical H-Beta zeolite showed higher activity and selectivity to the middle distillate than that containing microporous Beta zeolite in catalytic hydrocracking of vacuum gas oil (VGO) evaluated by an industrial pilot installation in running of 3000 h, due to the increased accessibility and the reduction of diffusion constraint of large molecules to acid sites in the Beta zeolite framework.

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Hydrocracking of vacuum gas oil over NiMo/Y-Al2O3: Effect of mesoporosity introduced by zeolite Y recrystallization

Cited by 54 publications

References 52 publications

Specific Surface Area Determination for Microporous/Mesoporous Materials: The Case of Mesoporous FAU-Y Zeolites

Specific Surface Area Determination for Microporous/Mesoporous Materials: The Case of Mesoporous FAU-Y Zeolites

Revelation on the Complex Nature of Mesoporous Hierarchical FAU-Y Zeolites

Practical Application of Hierarchical Beta Zeolite in a Vacuum Gas Oil Hydrocracking Catalyst

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