Deep desulfurization of gas oil over NiMo catalysts supported on alumina-zirconia composites

Mohammed A. Al-Daous; Syed A. Ali

doi:10.1016/j.fuel.2012.02.041

Deep desulfurization of gas oil over NiMo catalysts supported on alumina-zirconia composites

Mohammed A. Al-Daous, Syed A. Ali^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

33 Scopus citations

Abstract

A series of NiMo catalysts supported on Al ₂O ₃- ZrO ₂ composites containing 0, 2.5, 5 and 10 wt.% ZrO ₂ was synthesized, characterized and evaluated for deep desulfurization of gas oil. X-ray diffraction patterns of the supports indicate homogenous dispersion of 2.5-10 wt.% of ZrO ₂ in bulk Al ₂O ₃. Mono-modal pore-size distribution was observed with a decrease in average pore-size with increasing ZrO ₂ content. NH ₃-TPD results show that incorporation of 5 wt.% or more ZrO ₂ neutralized the weak acid sites of Al ₂O ₃ and generated a different type of stronger acid sites. UV-Visible diffuse reflectance spectroscopy results indicate the presence of tetrahedral and octahedral Mo ⁶⁺ ions species along with an increase in octahedral species with addition of ZrO ₂ possibly due to weaker interaction of active metals and composite support. This result is also supported by H ₂-TPR and CO chemisorption measurements. Deep desulfurization of gas oil, carried out in a bench-scale flow reactor at 320, 340 and 360°C, indicate that the addition of ZrO ₂ increased the catalytic activity - especially at higher temperature. Compared to Al ₂O ₃-based catalyst, the 1.5 order HDS rate constant was about 1.3, 1.8 and 2.5 times higher for catalysts containing 2.5, 5 and 10 wt.% ZrO ₂, respectively. A correlation was found between the enhancement of hydrogenation activity of sulfided catalysts and the reducibility of their oxide precursors, as determined by the amount of hydrogen consumed in TPR experiments followed by mass spectroscopy.

Original language	English
Pages (from-to)	662-669
Number of pages	8
Journal	Fuel
Volume	97
DOIs	https://doi.org/10.1016/j.fuel.2012.02.041
State	Published - Jul 2012

Bibliographical note

Funding Information:
The authors would like to acknowledge the support provided by King Abdulaziz City for Science and Technology (KACST) through the Science and Technology Unit at King Fahd University of Petroleum and Minerals (KFUPM) for funding the work through project No. 08-PET89-4 as part of the National Science, Technology and Innovation Plan. Acknowledgement is due to the Ministry of Higher Education, Saudi Arabia for establishing the Center of Research Excellence in Petroleum Refining and Petrochemicals (CoRE-PRP) at KFUPM.

Keywords

Alumina
Deep hydrodesulfurization
HDS
Zirconia

ASJC Scopus subject areas

General Chemical Engineering
Fuel Technology
Energy Engineering and Power Technology
Organic Chemistry

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10.1016/j.fuel.2012.02.041

Cite this

@article{3c41ab26f3b646d1a19f5d6e6742166d,

title = "Deep desulfurization of gas oil over NiMo catalysts supported on alumina-zirconia composites",

abstract = "A series of NiMo catalysts supported on Al 2O 3- ZrO 2 composites containing 0, 2.5, 5 and 10 wt.% ZrO 2 was synthesized, characterized and evaluated for deep desulfurization of gas oil. X-ray diffraction patterns of the supports indicate homogenous dispersion of 2.5-10 wt.% of ZrO 2 in bulk Al 2O 3. Mono-modal pore-size distribution was observed with a decrease in average pore-size with increasing ZrO 2 content. NH 3-TPD results show that incorporation of 5 wt.% or more ZrO 2 neutralized the weak acid sites of Al 2O 3 and generated a different type of stronger acid sites. UV-Visible diffuse reflectance spectroscopy results indicate the presence of tetrahedral and octahedral Mo 6+ ions species along with an increase in octahedral species with addition of ZrO 2 possibly due to weaker interaction of active metals and composite support. This result is also supported by H 2-TPR and CO chemisorption measurements. Deep desulfurization of gas oil, carried out in a bench-scale flow reactor at 320, 340 and 360°C, indicate that the addition of ZrO 2 increased the catalytic activity - especially at higher temperature. Compared to Al 2O 3-based catalyst, the 1.5 order HDS rate constant was about 1.3, 1.8 and 2.5 times higher for catalysts containing 2.5, 5 and 10 wt.% ZrO 2, respectively. A correlation was found between the enhancement of hydrogenation activity of sulfided catalysts and the reducibility of their oxide precursors, as determined by the amount of hydrogen consumed in TPR experiments followed by mass spectroscopy.",

keywords = "Alumina, Deep hydrodesulfurization, HDS, Zirconia",

author = "Al-Daous, {Mohammed A.} and Ali, {Syed A.}",

note = "Funding Information: The authors would like to acknowledge the support provided by King Abdulaziz City for Science and Technology (KACST) through the Science and Technology Unit at King Fahd University of Petroleum and Minerals (KFUPM) for funding the work through project No. 08-PET89-4 as part of the National Science, Technology and Innovation Plan. Acknowledgement is due to the Ministry of Higher Education, Saudi Arabia for establishing the Center of Research Excellence in Petroleum Refining and Petrochemicals (CoRE-PRP) at KFUPM.",

year = "2012",

month = jul,

doi = "10.1016/j.fuel.2012.02.041",

language = "English",

volume = "97",

pages = "662--669",

journal = "Fuel",

issn = "0016-2361",

}

TY - JOUR

T1 - Deep desulfurization of gas oil over NiMo catalysts supported on alumina-zirconia composites

AU - Al-Daous, Mohammed A.

AU - Ali, Syed A.

N1 - Funding Information: The authors would like to acknowledge the support provided by King Abdulaziz City for Science and Technology (KACST) through the Science and Technology Unit at King Fahd University of Petroleum and Minerals (KFUPM) for funding the work through project No. 08-PET89-4 as part of the National Science, Technology and Innovation Plan. Acknowledgement is due to the Ministry of Higher Education, Saudi Arabia for establishing the Center of Research Excellence in Petroleum Refining and Petrochemicals (CoRE-PRP) at KFUPM.

PY - 2012/7

Y1 - 2012/7

N2 - A series of NiMo catalysts supported on Al 2O 3- ZrO 2 composites containing 0, 2.5, 5 and 10 wt.% ZrO 2 was synthesized, characterized and evaluated for deep desulfurization of gas oil. X-ray diffraction patterns of the supports indicate homogenous dispersion of 2.5-10 wt.% of ZrO 2 in bulk Al 2O 3. Mono-modal pore-size distribution was observed with a decrease in average pore-size with increasing ZrO 2 content. NH 3-TPD results show that incorporation of 5 wt.% or more ZrO 2 neutralized the weak acid sites of Al 2O 3 and generated a different type of stronger acid sites. UV-Visible diffuse reflectance spectroscopy results indicate the presence of tetrahedral and octahedral Mo 6+ ions species along with an increase in octahedral species with addition of ZrO 2 possibly due to weaker interaction of active metals and composite support. This result is also supported by H 2-TPR and CO chemisorption measurements. Deep desulfurization of gas oil, carried out in a bench-scale flow reactor at 320, 340 and 360°C, indicate that the addition of ZrO 2 increased the catalytic activity - especially at higher temperature. Compared to Al 2O 3-based catalyst, the 1.5 order HDS rate constant was about 1.3, 1.8 and 2.5 times higher for catalysts containing 2.5, 5 and 10 wt.% ZrO 2, respectively. A correlation was found between the enhancement of hydrogenation activity of sulfided catalysts and the reducibility of their oxide precursors, as determined by the amount of hydrogen consumed in TPR experiments followed by mass spectroscopy.

AB - A series of NiMo catalysts supported on Al 2O 3- ZrO 2 composites containing 0, 2.5, 5 and 10 wt.% ZrO 2 was synthesized, characterized and evaluated for deep desulfurization of gas oil. X-ray diffraction patterns of the supports indicate homogenous dispersion of 2.5-10 wt.% of ZrO 2 in bulk Al 2O 3. Mono-modal pore-size distribution was observed with a decrease in average pore-size with increasing ZrO 2 content. NH 3-TPD results show that incorporation of 5 wt.% or more ZrO 2 neutralized the weak acid sites of Al 2O 3 and generated a different type of stronger acid sites. UV-Visible diffuse reflectance spectroscopy results indicate the presence of tetrahedral and octahedral Mo 6+ ions species along with an increase in octahedral species with addition of ZrO 2 possibly due to weaker interaction of active metals and composite support. This result is also supported by H 2-TPR and CO chemisorption measurements. Deep desulfurization of gas oil, carried out in a bench-scale flow reactor at 320, 340 and 360°C, indicate that the addition of ZrO 2 increased the catalytic activity - especially at higher temperature. Compared to Al 2O 3-based catalyst, the 1.5 order HDS rate constant was about 1.3, 1.8 and 2.5 times higher for catalysts containing 2.5, 5 and 10 wt.% ZrO 2, respectively. A correlation was found between the enhancement of hydrogenation activity of sulfided catalysts and the reducibility of their oxide precursors, as determined by the amount of hydrogen consumed in TPR experiments followed by mass spectroscopy.

KW - Alumina

KW - Deep hydrodesulfurization

KW - HDS

KW - Zirconia

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U2 - 10.1016/j.fuel.2012.02.041

DO - 10.1016/j.fuel.2012.02.041

M3 - Article

AN - SCOPUS:84861195536

SN - 0016-2361

VL - 97

SP - 662

EP - 669

JO - Fuel

JF - Fuel

ER -

Deep desulfurization of gas oil over NiMo catalysts supported on alumina-zirconia composites

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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