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Roel Prins - One of the best experts on this subject based on the ideXlab platform.
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mechanisms of hydrodesulfurization and Hydrodenitrogenation
Catalysis Today, 2006Co-Authors: Roel Prins, M Egorova, A Rothlisberger, Y Zhao, N Sivasankar, P KukulaAbstract:Abstract To study the problems inherent in deep hydrodesulfurization (HDS), the separate and simultaneous HDS of 4,6-dimethyldibenzothiophene and Hydrodenitrogenation (HDN) of pyridine were investigated over a Ni-MoS 2 /γ-Al 2 O 3 and a Pd/γ-Al 2 O 3 catalyst. The HDS of 4,6-dimethyldibenzothiophene and its three intermediates, 4,6-dimethyl-tetrahydro-dibenzothiophene, 4,6-dimethyl-hexahydro-dibenzothiophene and 4,6-dimethyl-dodecahydro-dibenzothiophene, demonstrated that, over the Pd catalyst, the (de)hydrogenation reactions were relatively fast compared to the C–S bond breaking reactions, whereas the reverse was true over the metal sulfide catalyst. The methyl groups of 4,6-dimethyldibenzothiophene strongly hinder the direct desulfurization HDS pathway over both catalysts. On the Pd catalyst the hydrogenation pathway is strongly promoted by the methyl groups, so that the total HDS rate does not decrease. Pyridine and piperidine were strong poisons for the hydrogenation pathway and H 2 S was a strong poison for the direct desulfurization pathway. HDN of nitrogen-containing aromatic molecules occurs by hydrogenation of the aromatic heterocycle followed by C–N bond breaking. The C–N bond breaks by substitution of the alkylamine by H 2 S to form an alkanethiol, followed by the loss of H 2 S by elimination or hydrogenolysis. The NH 2 -SH substitution does not occur by a classic organic substitution reaction but through a multi-step reaction pathway via an alkylimine. DFT calculations showed that the hydrogenolysis of ethanethiol to ethane and the elimination of ethane are relatively easy reactions.
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a novel approach to synthesizing highly active ni2p sio2 hydrotreating catalysts
Journal of Catalysis, 2006Co-Authors: Shaofeng Yang, Changhai Liang, Roel PrinsAbstract:Silica-supported nickel phosphide particles with high dispersion were obtained by treating nickel metal particles on a support with 10% PH3/H2. Because the phosphidation occurred at relatively low temperature, the small nickel phosphide particles had the same size as the metal particles, and this size was maintained. The resulting catalysts were characterized by CO and O2 chemisorption, XRD, and 31P MAS NMR spectroscopy. The influence of the nickel source on the metal dispersion of the catalysts was investigated. The resulting silica-supported nickel phosphide catalysts proved to be very active in the hydrodesulfurization of dibenzothiophene and the Hydrodenitrogenation of o-methylaniline in the presence and absence of H2S.
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competitive hydrodesulfurization of 4 6 dimethyldibenzothiophene Hydrodenitrogenation of 2 methylpyridine and hydrogenation of naphthalene over sulfided nimo γ al2o3
Journal of Catalysis, 2004Co-Authors: Marina Egorova, Roel PrinsAbstract:Abstract The hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene (4,6-DMDBT) was studied at 340 °C and 5 MPa in the presence of 2-methylpyridine and 2-methylpiperidine. Both N-containing molecules inhibited the HDS. The inhibitory effect of 2-methylpiperidine on the direct desulfurization and hydrogenation pathways of the HDS was slightly stronger than that of 2-methylpyridine. The desulfurization of 4,6-dimethyltetrahydrodibenzothiophene, an intermediate in the hydrogenation pathway, was extremely difficult in the presence of N-containing molecules. 4,6-DMDBT, in turn, inhibited the hydrogenation of 2-methylpyridine to 2-methylpiperidine but did not affect the CN bond cleavage in the Hydrodenitrogenation of 2-methylpiperidine. The use of toluene as an aromatic solvent had no effect on the HDS of dibenzothiophene and 4,6-DMDBT at 340 °C. Naphthalene inhibited the HDS of dibenzothiophene and 4,6-DMDBT without changing the product distributions. Both S-containing molecules suppressed the hydrogenation of naphthalene to the same extent.
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mutual influence of the hds of dibenzothiophene and hdn of 2 methylpyridine
Journal of Catalysis, 2004Co-Authors: Marina Egorova, Roel PrinsAbstract:Abstract The influence of 2-methylpyridine and 2-methylpiperidine on the hydrodesulfurization of dibenzothiophene (DBT) and the effect of DBT on the Hydrodenitrogenation of 2-methylpyridine and 2-methylpiperidine were studied over a sulfided NiMo/Al 2 O 3 catalyst at 5 MPa, 35 kPa H 2 S, and 300 and 340 °C. Both N-containing molecules strongly suppressed the hydrogenation pathway of the hydrodesulfurization of DBT and inhibited the direct desulfurization route at both reaction temperatures. The inhibitory effect on the direct desulfurization was stronger for 2-methylpyridine than for 2-methylpiperidine. H 2 S promoted the hydrogenation of 2-methylpyridine up to 10 kPa and inhibited it at higher partial pressures. H 2 S had a positive influence on the Hydrodenitrogenation conversions of 2-methylpiperidine and 2-methylpyridine. DBT had a negative effect on the hydrogenation of 2-methylpyridine, but did not influence the CN bond cleavage of 2-methylpiperidine. Therefore, CN and CS bond breaking takes place at different active sites, whereas the hydrogenation sites for N- and S-containing molecules may be the same.
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synthesis and characterization of silica supported transition metal phosphides as hdn catalysts
Journal of Catalysis, 2003Co-Authors: V Zuzaniuk, Roel PrinsAbstract:Supported transition-metal phosphides (Co2P/SiO2, MoP/SiO2, WP/SiO2, CoMoP/SiO2, and NiMoP/SiO2) were prepared by means of pore-volume impregnation of a silica support. The metal oxide/phosphate precursors were reduced either in pure H2 or in a flow of 4.8% H2 in Ar. The materials obtained were characterized by CO chemisorption, powder X-ray diffractometry, and 31P MAS NMR spectroscopy. The catalysts were tested in the Hydrodenitrogenation of o-methylaniline at 643 K and 3 MPa in the presence and absence of H2S. All the materials were active in this reaction, MoP/SiO2 displaying the highest catalytic activity. In the presence of H2S, all the catalysts lost some activity.
Francoise Mauge - One of the best experts on this subject based on the ideXlab platform.
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effect of mg addition on the structure and performance of sulfide mo al2o3 in hds and hdn reaction
Journal of Catalysis, 2016Co-Authors: Wenbin Chen, Hong Nie, Xiangyun Long, Jacob Van Gestel, Francoise MaugeAbstract:Abstract The effect of Mg addition on alumina on the properties of sulfided Mo/Al2O3Mg(x) (x = 0–3.2 wt.% Mg) catalysts has been investigated using various characterization techniques (transmission electron microscopy, X-ray photoelectron spectroscopy, infrared spectroscopy) and catalytic tests (hydrodesulfurization of 4,6-dimethyldibenzothiophene and Hydrodenitrogenation of 2,6-dimethylaniline). It is observed that Mg addition decreases the weak Bronsted acidity and increases the basicity of the alumina support. Mg addition also increases the electronic density of the MoS2 slabs, as revealed by the shift of the frequency of CO adsorbed on the sulfide Mo phase. A parallel between the increase of the electronic density of the sulfide slabs and the decrease of the Bronsted acidity of the support is evidenced. The addition of Mg does not lead to significant changes of dispersion of the MoS2 phase but tends to decrease its stacking. The addition of a small amount of Mg increases the hydrogenation activity of the Mo catalysts for hydrodesulfurization and Hydrodenitrogenation. This beneficial effect is more marked in case of co-addition of Mg and B. These data show that the addition of Mg, through the modification of the electronic properties of the sulfide sites and by the presence of Mg, leads to improvement of the intrinsic hydrogenation activity of Mo catalyst supported on alumina.
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effect of nta addition on the structure and activity of the active phase of cobalt molybdenum sulfide hydrotreating catalysts
Journal of Catalysis, 2009Co-Authors: M A Lelias, Arnaud Travert, P J Kooyman, L Mariey, L Oliviero, J Van Gestel, J A R Van Veen, Francoise MaugeAbstract:CoMoS catalysts with constant Co and Mo contents were prepared with different amounts of nitrilo triacetic acid (NTA) chelating agent. NTA has a marked positive effect on the catalyst activity for gas-phase reactions such as atmospheric pressure thiophene hydrodesulfurization (HDS) and high-pressure 2,6dimethyl aniline Hydrodenitrogenation, whereas no effect is found for liquid-phase dibenzothiophene HDS. Transmission electron microscopy analysis shows that NTA has no effect on MoS2 slab size and stacking, while infrared spectroscopy of adsorbed CO reveals a strong increase in the amount of Co-promoted sites. Comparison of activity and spectroscopic data implies that increase of Co-promoted sites accounts for the catalytic activity enhancement, but it also provides evidences for the creation of different kinds of sites on the NTA catalysts. Various possibilities (type II CoMoS phase, Co clusters, or CoMoSN) are discussed.
And A Stanislaus - One of the best experts on this subject based on the ideXlab platform.
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atmospheric residue desulfurization process for residual oil upgrading an investigation of the effect of catalyst type and operating severity on product oil quality
Energy & Fuels, 2006Co-Authors: Abdulazeem Marafi, Andre Hause, And A StanislausAbstract:Atmospheric residue desulfurization (ARDS) process is extensively used in upgrading of heavy petroleum oils and residues to more valuable clean environmentally friendly transportation fuels and to partially convert the residues to produce low-sulfur fuel oil and hydrotreated feedstocks. Graded catalyst systems in multiple reactors are used in the process in order to achieve hydrodesulfurization (HDS), hydrodemetallization (HDM), Hydrodenitrogenation (HDN), and conversion of residues to distillates at desired levels. The characteristics of the feedstocks processed in different reactors are significantly different. The quality of the feed entering the second reactor is strongly dependent on the operating severity in the first reactor and can have an important impact on the performance of the catalysts in the following reactor with regard to various conversions and deactivation rate. In the present work, a systematic study was conducted on the effect of two industrial catalyst types, namely, MoO3/Al2O3 (HDM)...
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relation between feed quality and coke formation in a three stage atmospheric residue desulfurization ards process
Energy & Fuels, 2005Co-Authors: Andre Hause, Abdulazeem Marafi, And A Stanislaus, Awatef AladwaniAbstract:In this study, the effect of three different feedstocksnamely, straight-run atmospheric residue (AR), demetallized AR (DM-AR), and demetallized/desulfurized AR (DMDS-AR)on the coke formation on an industrial catalyst system consisting of a hydrodemetallization (HDM) catalyst (A), a hydrodemetallization/hydrodesulfurization (HDM/HDS) catalyst (B), and a hydrodesulfurization/Hydrodenitrogenation (HDS/HDN) catalyst (C) were examined. The used catalysts, aged under the same operating conditions (catalyst A with atmospheric residue (AR), B with AR or demetallized atmospheric residue (DM-AR), C with AR or demetallized and desulfurized atmospheric residue (DMDS-AR)), were characterized by combining physical/chemical analyses with temperature-programmed oxidation/mass spectroscopy (TPO/MS) and solid-state 13C nuclear magnetic resonance (NMR). Special emphasis was made on finding a relationship between feed quality and the amount and nature of coke. The results revealed that hydrotreated feeds generate significant...
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a comparative study of the effect of catalyst type on hydrotreating kinetics of kuwaiti atmospheric residue
Energy & Fuels, 2003Co-Authors: Abdulazeem Marafi, Sachiko Fukase, And M Almarri, And A StanislausAbstract:In the upgrading of heavy petroleum oils and residues by hydrotreating, multiple-reactor fixed-bed units loaded with different types of catalysts are extensively used. Catalysts for such hydrotreating processes are chosen on the basis of activity, selectivity, and life. The performance of the overall hydrotreating process with regard to various reactions, such as hydrodemetallation (HDM), hydrodesulfurization (HDS), Hydrodenitrogenation (HDN), asphaltenes cracking (HDAsph), and conversion to distillate and catalyst life-on-stream, is clearly linked to the performance of the catalyst in different reactors. Information regarding the activity, selectivity, kinetics parameters, and deactivation of the individual catalysts are, therefore, highly desirable for optimizing reactor loading in a multiple catalyst system. In the present work, a comparative study was conducted on the kinetics of various reactions such as HDS, HDV, HDNi, HDN, CCR reduction, and asphaltenes conversion in hydrotreating Kuwaiti atmospher...
Abdulazeem Marafi - One of the best experts on this subject based on the ideXlab platform.
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atmospheric residue desulfurization process for residual oil upgrading an investigation of the effect of catalyst type and operating severity on product oil quality
Energy & Fuels, 2006Co-Authors: Abdulazeem Marafi, Andre Hause, And A StanislausAbstract:Atmospheric residue desulfurization (ARDS) process is extensively used in upgrading of heavy petroleum oils and residues to more valuable clean environmentally friendly transportation fuels and to partially convert the residues to produce low-sulfur fuel oil and hydrotreated feedstocks. Graded catalyst systems in multiple reactors are used in the process in order to achieve hydrodesulfurization (HDS), hydrodemetallization (HDM), Hydrodenitrogenation (HDN), and conversion of residues to distillates at desired levels. The characteristics of the feedstocks processed in different reactors are significantly different. The quality of the feed entering the second reactor is strongly dependent on the operating severity in the first reactor and can have an important impact on the performance of the catalysts in the following reactor with regard to various conversions and deactivation rate. In the present work, a systematic study was conducted on the effect of two industrial catalyst types, namely, MoO3/Al2O3 (HDM)...
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an investigation of the deactivation behavior of industrial mo al2o3 and ni mo al2o3 catalysts in hydrotreating kuwait atmospheric residue
Petroleum Science and Technology, 2005Co-Authors: Abdulazeem Marafi, Andre Hause, A Stainslaus, Koichi MatsushitaAbstract:Abstract The catalyst system for fixed-bed residue hydrotreating processes usually consists of different types of catalysts designed to promote hydrodemetallation (HDM), hydrodesulfurization (HDS) and Hydrodenitrogenation (HDN) reactions to desired levels. Overall catalyst life is determined by the performance of the individual catalysts in the different reactors. Therefore, information about the activity, stability, selectivity, and deactivation behavior of the individual catalyst is highly desirable to design improved catalysts that can prolong catalyst life, increase stream efficiency, and improve process economics. In the present work, residue hydrotreating experiments were conducted on two types of industrial hydrotreating catalysts, namely Mo/Al2O3 and Ni-Mo/Al2O3, that have been used as HDM and HDS catalysts, respectively, in an industrial ARDS process. The primary objective of the study was to compare the deactivation behavior of both types of catalyst. The characterization of the used catalysts b...
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relation between feed quality and coke formation in a three stage atmospheric residue desulfurization ards process
Energy & Fuels, 2005Co-Authors: Andre Hause, Abdulazeem Marafi, And A Stanislaus, Awatef AladwaniAbstract:In this study, the effect of three different feedstocksnamely, straight-run atmospheric residue (AR), demetallized AR (DM-AR), and demetallized/desulfurized AR (DMDS-AR)on the coke formation on an industrial catalyst system consisting of a hydrodemetallization (HDM) catalyst (A), a hydrodemetallization/hydrodesulfurization (HDM/HDS) catalyst (B), and a hydrodesulfurization/Hydrodenitrogenation (HDS/HDN) catalyst (C) were examined. The used catalysts, aged under the same operating conditions (catalyst A with atmospheric residue (AR), B with AR or demetallized atmospheric residue (DM-AR), C with AR or demetallized and desulfurized atmospheric residue (DMDS-AR)), were characterized by combining physical/chemical analyses with temperature-programmed oxidation/mass spectroscopy (TPO/MS) and solid-state 13C nuclear magnetic resonance (NMR). Special emphasis was made on finding a relationship between feed quality and the amount and nature of coke. The results revealed that hydrotreated feeds generate significant...
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a comparative study of the effect of catalyst type on hydrotreating kinetics of kuwaiti atmospheric residue
Energy & Fuels, 2003Co-Authors: Abdulazeem Marafi, Sachiko Fukase, And M Almarri, And A StanislausAbstract:In the upgrading of heavy petroleum oils and residues by hydrotreating, multiple-reactor fixed-bed units loaded with different types of catalysts are extensively used. Catalysts for such hydrotreating processes are chosen on the basis of activity, selectivity, and life. The performance of the overall hydrotreating process with regard to various reactions, such as hydrodemetallation (HDM), hydrodesulfurization (HDS), Hydrodenitrogenation (HDN), asphaltenes cracking (HDAsph), and conversion to distillate and catalyst life-on-stream, is clearly linked to the performance of the catalyst in different reactors. Information regarding the activity, selectivity, kinetics parameters, and deactivation of the individual catalysts are, therefore, highly desirable for optimizing reactor loading in a multiple catalyst system. In the present work, a comparative study was conducted on the kinetics of various reactions such as HDS, HDV, HDNi, HDN, CCR reduction, and asphaltenes conversion in hydrotreating Kuwaiti atmospher...
John Adjaye - One of the best experts on this subject based on the ideXlab platform.
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effects of hydrogen partial pressure on hydrotreating of heavy gas oil derived from oil sands bitumen experimental and kinetics
Energy & Fuels, 2010Co-Authors: M Mapiour, V. Sundaramurthy, Ajay Kumar Dalai, John AdjayeAbstract:The effect of hydrogen partial pressure (H2 pp) on hydrotreating conversions, feed vaporization, H2 dissolution, and H2 consumption was studied in a micro trickle-bed reactor, using a commercial NiMo/γ-Al2O3 catalyst. Heavy gas oil (HGO) from Athabasca bitumen was used as feed. The H2 pp level was set inside the reactor by means of manipulating other operating variables, namely, H2 purity, pressure, gas/oil ratio, liquid hourly space velocity (LHSV), and temperature. Their ranges were as follows: 75−100 vol % (with the rest methane), 7−11 MPa, 400−1200, 0.65−2 h−1, and 360−400 °C, respectively. HYSYS was used to determine the inlet and outlet H2 pp. The results show that Hydrodenitrogenation (HDN) and hydrodearomatization (HDA) are significantly more affected by H2 pp than hydrodesulfurization (HDS), with HDN being the most affected. Moreover, it was observed that H2 dissolution and H2 consumption increase with increasing H2 pp. No clear trend was observed for the effect of H2 pp on feed vaporization. Kin...
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effect of hydrogen purity on hydroprocessing of heavy gas oil derived from oil sands bitumen
Energy & Fuels, 2009Co-Authors: M Mapiour, V. Sundaramurthy, Ajay Kumar Dalai, John AdjayeAbstract:The effect of hydrogen purity on hydroprocessing of heavy gas oil (HGO) was studied in a trickle bed reactor over a commercial Ni−Mo/γ-alumina catalyst. Methane was used as a diluent for the hydrogen stream, and its effect on the catalyst performance was compared to that of helium, which is inert toward the catalyst. Furthermore, a deactivation study was conducted over a period of 66 days, during which the catalyst was subjected to H2 purity ranging from 95 to 75% (with the rest methane); no significant deterioration in the hydroprocessing activities of the catalyst was observed. Therefore, it was concluded that methane was inert toward a commercial Ni−Mo/γ-alumina catalyst. However, its presence resulted in hydrogen partial pressure reduction, which in turn led to a decrease in hydrodesulphurization (HDS), Hydrodenitrogenation (HDN), hydrodearomatization (HDA) conversions. This reduction can be offset by increasing the total pressure of the system. HDS, HDN, HDA, and mild hydrocracking (MHC) conversions ...
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comparison of Hydrodenitrogenation of model basic and nonbasic nitrogen species in a trickle bed reactor using commercial nimo al2o3 catalyst
Energy & Fuels, 2003Co-Authors: Deena Ferdous, A K Dalai, John AdjayeAbstract:A systematic study has been conducted in a trickle-bed reactor using a commercial NiMo/Al2O3 catalyst to understand the effects of different variables such as H2S concentration in the feed by adding different amount of butanethiol, reaction pressure, temperature, liquid hourly space velocity (LHSV), and H2/feed ratio on the Hydrodenitrogenation (HDN) of typical basic (acridine) and nonbasic (carbazole and 9-ethylcarbazole) nitrogen compounds present in heavy gas oil. The HDN conversion of basic compound was higher than that of nonbasic compounds at all butanethiol concentrations (0−4 wt %) in the feed. The HDN conversion of acridine was 98−99 wt % at 355−400 °C, whereas, with an increase in temperature from 355 to 400 °C, the conversion of carbazole and 9-ethylcarbazole increased somewhat from 92 to 95 wt % and from 94 to 97 wt %, respectively. Pressure (1120−1420 psig) had no effect on the HDN conversion of basic and nonbasic nitrogen compounds. Also, an increase in LHSV did not have a significant effect...