Activity and Selectivity of Hydrotreating Catalysts

Ahuja, Sonal; Derrien, M.; Page, J. F. Le

doi:10.1021/i360035a003

Cited by 82 publications

(28 citation statements)

References 1 publication

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Section: C 2 Materials (A) Catalystsmentioning

confidence: 87%

“…We have shown elsewhere (49) that these low surface area catalysts realistically mimic the catalytic behavior of their high surface area Y-Al 2 0 3 counterparts, and are more amenable for study in the ultra high vacuum environment of XPS. The preparation procedure has alreay been outlined in detail (49). Briefly, 1 cm2 slabs of non-porous PCA (99.9% Al 2 0 3 , Grade AD-999, Coors Porcelain Company) were meticulously cleaned by alternate soakings in chromic acid-sulfuric acid cleaning solution (Fisher Scientific Company) and distilled water.…”

Section: C 2 Materials (A) Catalystsmentioning

confidence: 87%

“…Details of the spectrometer system and its use in analyzing model PCA catalysts have been given elsewhere (49). Briefly, the 35 spectrometer is a Perkin-Elmer Physical Electronics Model 548 which has been digitally interfaced to a PHI Multiple-technique Analytical Computer System (MACS) supplied by PHI (Eden Prairie, MN).…”

Section: Ic3 Hydrodemetallation Experiment-proceduresmentioning

confidence: 99%

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Catalytic hydrodemetallation of nickel porphyrins: reactivity and catalyst surface studies

1984

Applied Catalysis

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The kinetics and mechanism of hydrodemetallation (HDM) of nickel etioporphyrin (NI-EP) and nickel tetra(3-methylphenyl) porphyrin (Ni-T3MPP) have been studied using alumina supported Group VIII metals, Co-Mo, and Ni-Mo as catalysts, and a white oil as a solvent. The metalloporphyrin solution simulates a metals containing residua, and was demetallized at 1000 psig H and temperatures in the range 300 to 375*C. Over all catalysts, goth porphyrins react via a sequential mechanism, involving initial hydrogenation to activate the porphyrin, followed by terminal hydrogenolysis which cleaves the ring, and deposits nickel onto the catalyst surface. While the global HDM mechanism is the same for both porphyrins, the intricacies of the HDM scheme are intimately linked to the structural differences on the periphery of the tetra-pyrrolic ring. With the Group VIII metals/Y-Al 0 the selectivity of the HDM mechanism (terminal hydrogenolysis riti constant/initial hydrogenation rate constant) has been varied over two orders of magnitude. Group VIII metals favor hydrogenolysis, while the Group VIII metals have a high ;electivity for hydrogenation. The HDM activity of lhe Group VIII metals is comparable to that of Co-Mo.Ni-EP was reacted over a series of Ru-Cu/Al 0 catalysts. The addition of Cu to the Ru system suppresses the rate of ih hydrogenolysis reaction, while having little effect on the hydrogenation reaction. Based on XPS measurements these observations were rationalized by geometrical effects. XPS also indicated that the chemical state of nickel deposited on a catalyst via HDM differs from its state and degree of interaction with the support in a Ni-Mo/Al 2 0 3 catalyst.Oil soluble cobalt and molybdenum napthenates were also dissolved in the white oil, and demetallized over bare T-Al 0 support at temperatures of 290*C and 360*C, and pressures of 500 and 1000 psig H 2 . These in situ synthesized Co-Mo catalysts were subsequently used in Ni-T3MPP HDM. The catalysts which were generated at 360*C, 1000 psig H 2 had a higher Ni-T3MPP HDM activity than the commercially manufactured Co-Mo/A1 2 0 3 . SEM/EDX and AES measurements indicate that a thick carbonaceous overlayer envelopes the Al 0 particles during napthenate demetallation. However this overlayer remaPns porous enough to permit all metals to ultimately deposit on the alumina.Model, non-porous polycrystalline alumina supported Co-Mo catalysts were made with surface compositions in the range 0<[Co/(Co+Mo)]<1 and used for Ni-T3MPP HDM. The catalysts were aged in HDMexperiments Tn a spinning basket reactor at 360*C and 1000 psig H The aged catalysts were scrutinized by a variety of surface spe~troscopic techniques (XPS, AES, SIMS, ISS and SEM/EDX). HDM activity was a maximum in the range 0.5<[Co6{Co+Mo) <0.7. Thf~initia 1 ly oxidic catalysts were reduced during HDM (Mo to Mo , and Co to Co ). Both metallic Ni and NiO were observed on the aged catalysts, however, the latter entity is most probably a result of air contamination, and it is not present in the working HD...

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Section: C 2 Materials (A) Catalystsmentioning

confidence: 87%

Section: C 2 Materials (A) Catalystsmentioning

confidence: 87%

Section: Ic3 Hydrodemetallation Experiment-proceduresmentioning

confidence: 99%

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Catalytic hydrodemetallation of nickel porphyrins: reactivity and catalyst surface studies

1984

Applied Catalysis

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“…HDS catalysts are based on CoMo/ Al2O3 or NiMo/Al2O3 with various modifications, such as use of tungsten instead of molybdenum 2) 9) , additives such as silica 10) 15) , phosphorus 16) 24) , boria 13),22), 25) 28) , fluorine 29) 35) , zeolite related materials 36) 42) , titania 13),43) 51) and others, and optimized preparation method and physicochemical properties s u c h a s s h a p e , p o r e s i z e d i s t r i b u t i o n , a n d others 15 . Strangely enough, the origin of HDS catalysts is rarely described.…”

Section: Randd History Of Hds Catalystmentioning

confidence: 99%

Regeneration of Residue Hydrodesulfurization Catalyst

Iwamoto

2013

J. Jpn. Petrol. Inst.

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Reuse of residue hydrodesulfurization catalyst is very important, as a large volume of this catalyst is exchanged every year due to the high deactivation rate. However, stable regeneration of this catalyst is more difficult than for distillate HDS catalysts due to the more severe regeneration conditions and the presence of vanadium. Regeneration technologies of residue hydrodesulfurization catalyst are reviewed to assess the differences between regeneration of distillate HDS catalysts, mechanism of residue HDS catalyst regeneration, commercial regeneration, properties, structure, and activities of regenerated residue HDS catalyst, effect of vanadium and improvement of catalyst suitable for regeneration. The presence of vanadium accelerates both insufficient recovery of activity and reduced catalyst strength due to formation of NiMoO4 and Al2(SO4)3, respectively. However, removal of vanadium might be not essential. Vanadium acts indirectly as oxidative catalyst and increases the regeneration temperature and transformation of SOx into H2SO4. Therefore, milder regenerated conditions and control of the properties of used catalyst as well as improvement of catalyst may allow improved regeneration.

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“…Molybdenum, in the absence of cobalt, is quite active while the converse is not true (4,5). The addition of cobalt enhances the HDS activity, which exhibits a peak in the range Co/(Co+Mo) =.2-.45 (6)(7)(8)(9)(10). In addition to hydrodesulfurization, these catalysts are also good hydrogénation, HYD, catalysts and are therefore bifunctional in nature.…”

Section: Introductionmentioning

confidence: 99%

I. A mechanistic study of the hydrodesulfurization of methanethiol over tungsten disulfide; II. A survey of rare earth sulfides for hydrodesulfurization activity

Dowd

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Activity and Selectivity of Hydrotreating Catalysts

Cited by 82 publications

References 1 publication

Catalytic hydrodemetallation of nickel porphyrins: reactivity and catalyst surface studies

Catalytic hydrodemetallation of nickel porphyrins: reactivity and catalyst surface studies

Regeneration of Residue Hydrodesulfurization Catalyst

I. A mechanistic study of the hydrodesulfurization of methanethiol over tungsten disulfide; II. A survey of rare earth sulfides for hydrodesulfurization activity

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