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No. of bitstreams: 1 aryrodriguesferreirajunior.pdf: 3094807 bytes, checksum: 6847722cf7c001b55fb374bb7d01b63a (MD5) Previous issue date: 2013-11-28 / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / A alumina, Al2O3, é um material largamente utilizado na indústria. A fase   é o α produto mais estável da calcinação de hidróxidos e oxi­hidróxidos como a boehmita,  γ AlO(OH), a bayerita,  ­Al(OH) α 3, e a gibbsita  ­Al(OH) γ 3, acima de 1.000°C. Em temperaturas intermediárias, diferentes fases da alumina podem ser observadas, as quais são denominadas aluminas de transição ( ,  ,  ,  ,   e  ). A fase   deste óxido é reconhecida como um material η γ χ δ κ θ γ extremamente   importante   em   vários   processos   industriais   atuando   como   adsorvente, catalisador ou suporte. Esta alumina de transição é muito utilizada na indústria petroquímica como suporte para catalisadores a base de sulfetos de metais de transição Co(Ni)MoS no processo de hidrotratamento (HDT). O polidimetilsiloxano (PDMS) é um polímero de fórmula geral [(CH3)2SiO]n, empregado como fluído de perfuração na indústria do petróleo, porém a sua aplicação como agente antiespumante em processos de transformação e tratamento nas refinarias merece maior atenção, devido ao problema da contaminação de catalisadores utilizados no processo de HDT. A sua degradação pode ocorrer a temperaturas superiores a 400°C alcançadas nos processos térmicos não catalíticos. Logo, as frações do petróleo que seguem para o processo de HDT, como a nafta leve e pesada ou o óleo diesel, já podem estar carregando para o reator oligômeros em concentrações suficientes para a desativação do catalisador. Neste trabalho, a Teoria do Funcional da Densidade (DFT)   foi utilizada na modelagem das superfícies (100) e (110) da  ­alumina e também da fase ativa do catalisador γ MoS/ ­Al γ 2O3. Foi possível realizar a simulação de propriedades como os parâmetros espectrais de Ressonância Magnética Nuclear de Estado Sólido de 27Al e 29Si bem como as frequências vibracionais dos modos normais associados aos grupos hidroxila superficiais. Este conjunto de simulações permitiu que uma série de trabalhos experimentais relevantes relacionados à caracterização das superfícies do óxido e do catalisador envenenado fossem revisitados. Com a termodinâmica estatística foi possível discutir a presença de sítios ácidos de Lewis tricoordenados AlIII em amostras do suporte submetidas a tratamento térmico. Uma análise de energias livres dos primeiros estágios do envenenamento do catalisador sugeriu que os sítios ácidos de Brønsted do suporte são consumidos preferencialmente. / Alumina, Al2O3, is a material widely used in the industry. The   phase is the most α stable product in the calcination of boehmite,  ­ AlO(OH), bayerite  ­Al(OH) γ α 3, and gibbsite ­Al(OH)γ 3, at temperatures above 1.000°C. At intermediate temperatures, different phases of alumina can be observed, which are termed transition aluminas ( ,  ,  ,  ,   e  ). The   phase η γ χ δ κ θ γ of this oxide is known as an extremely important material in a number of industrial processes acting as an adsorbent, a catalyst or a catalyst support. This transition alumina is extensively used in petroleum and petrochemical industries as a support for transition­metal sulfides Co(Ni)MoS in hydrotreatment (HDT) process. Polydimethylsiloxane (PDMS) is a polymer with chemical formula [(CH3)2SiO]n applied in the oil industry as a drilling fluid, but its application as an anti­foaming agent in oil refineries deserves attention, because of the problem associated with catalyst deactivation in the HDT process. Its degradation can occur at temperatures exceeding 400°C in non­catalytic thermal processes. So, some oil fractions which follows to the HDT process, as naphtha or diesel, may already be carrying to the reactor some oligomers like siloxanes, silanes, and silanols, in very low concentrations, but enough for catalyst deactivation due to the accumulation of silicon over the surfaces.  In the present work, the Densidty Functional Theory (DFT) was used for the modeling of the (100) and (110) surfaces of  ­alumina as well as of the active phase of MoS/ ­Al γ γ 2O3 catalyst. With the structural models it was possible to perform simulations of properties like the 27Al and 29Si Solid­State Nuclear Magnetic Resonance spectral parameters as well as the vibrational frequencies of the normal modes associated with the surfaces hydroxyl groups. With this set of simulated data, it was possible to reassess a number of experimental works related to the characterization of the oxide surfaces and the catalyst poisoning. From statistical thermodynamics, the presence of tri­coordinated Lewis acid sites AlIII in samples subjected to thermal treatment was discussed and a free energy analysis considering the first steps of the catlyst poisoning process suggested that the Brønsted acid sites of the support are consumed preferentially.

In this thesis work the hydrogenation kinetics of phenanthrene inhibited by the basic nitrogen compound acridine and the non-basic carbazole was investigated. Based on a transient reactor model a steady state plug flow model was developed and kinetic parameters were estimated through nonlinear regression to experimental data. The experimental data was previously collected from hydrotreating of phenanthrene in a bench-scale reactor packed with a commercial NiMo catalyst mixed with SiC. As a first two-step solution, the yields of the hydrogenation products of phenanthrene were predicted as a function of conversion, which subsequently was used to calculate concentration profiles as a function of position in reactor. As a second improved solution, the concentration profiles were calculated directly as a function of residence time, and these results were then used for further analysis. Reaction network 2 in figure 7 was considered sufficient to describe the product distribution of phenanthrene, with a pseudo-first-order rate law for the nitrogen compounds. Both solution methods provided similar results which gave good predictions of the experimental data, with a few exceptions. These cases could be improved by gathering more experimental data or by investigating the effect of some model assumptions. The two-step method thus proved useful in evaluating the phenanthrene reaction network and providing an initial estimate of the parameters, while the onestep method then could give a more precise solution by calculating all parameters simultaneously. As expected, acridine was shown to be more inhibiting than carbazole, both in the produced concentration profiles and estimated parameters. A possible saturation effect was also seen in the inhibition behavior, where adding more nitrogen compounds only had a small additional effect on the phenanthrene conversion. The Mears and Weisz-Prater criteria were found to be inversely proportional to the concentrations of the nitrogen compounds and otherwise only depend on rate constants, with values well below limits for diffusion controlled processes. Sensitivity analyses also supported that the global minimum had been found in the nonlinear regression solution.

No

Hydrering är en viktig process för att producera produkter med önskade egenskaper samt att uppfylla de lagliga krav som existerar med avseende på miljö och hälsa. Reaktionerna som sker vid hydreringen är katalytiska vilket innebär att förstå sam utnyttja de mest lämpliga katalysatorerna är av yttersta vikt. Avsvavling (HDS) är en av de mest studerade reaktionerna medan avaromatisering (HDA) samt borttagandet av kväve (HDN) är diskuterade samt förstådda i lägre grad. Trots det är aromatiska samt kväverika föreningar naturligt förekommande i matningar till hydreringsreaktorerna där de organiska kväveföreningarna är inhibitorer. I detta arbete är målet att tillverka samt utvärdera några hydreringskatalysatorer med fokus på deras prestanda för HDA och HDN reaktionerna. Den bästa möjliga tekniken idag för tillverkningen av hydreringskatalysatorer utnyttjar kelateringsreagens vid beredningen. Detta har visat sig ha en positiv inverkan på egenskaperna och aktivteten vid hydrering för NiMo-katalysatorer. För att undersöka detta närmare har två typer av katalysatorer tillverkats, en med kelateringsreagens (typ II) och en utan (typ I). Dessa var sedan utvärderade i dess HDA och HDN aktiveter. Katalysatorerna var tillverkade samt karaktäriserade vid KTH och sedan aktiverade via sulfidering samt utvärderade vid Nynas AB. Aktiviteten för de sulfiderade katalysatorerna var utvärderade i ett surrogatsystem bestående av fenantren (PHE) som modell för aromatiska föreningar samt karbazol (CBZ) eller akridin (ACR) som modell för icke-basiskt samt basiskt organisk-kväve. Aktivitetsutvärderingen utfördes i en porlbäddreaktor där aktiviteten undersöktes vid närvarandet samt avsaknandet av de organiska kväveföreningarna. När matningen byttes, en så kallad modeswitch, ändras aktiviteten beroende på de betingelser som undersöktes. Reaktortemperaturen varierade mellan 300 °C och 320 °C vid ett konstant systemtryck på 120 barg. Katalysatornsaktivitet var positivt korrelerad med reaktortemperaturen där en lägre aktivtetuppmättes vid 300 °C jämfört med 320 °C. Det visade sig även att båda typerna av organiskt kväve påverkade aktivteten negativt vid båda undersökta temperaturerna. Utöver det så var de basiska kväveföreningarna mer inhiberande jämfört med de icke-basiska föreningarna för båda katalysatorerna. Inhiberingen orsakad av karbazol visade sig vara helt reversibel medan akridininhiberingen antydde på mer permanenta effekter för typ II katalsatorn. Dessa resultat antyder, trots de preliminära antagandena, att typ I katalysatorn var bättre än typ II katalysatorn. / Hydrotreating processes are of high importance in helping to obtain the desired characteristics of products as well as to comply with the legislation regarding health hazards and environmental pollution. Hydrotreating reactions are catalytic reactions which imply that the understanding and utilization of the most suitable catalysts is crucial. While hydrodesulfurization is a vastly studied branch of hydrotreating, hydrodearomatization (HDA), and hydrodenitrogenation (HDN) processes are less discussed and understood. However, aromatic compounds along with nitrogen-containing inhibitors are naturally present in the hydrotreater feeds. Therefore, the aim of this study was the preparation and evaluation of hydrotreating catalysts with the main focus on HDA and HDN reactions. According to the current state of the art, the utilization of chelating agents during preparation has a positive impact on the characteristics and activity of hydrotreating catalysts therefore NiMo catalysts with (Type II) and without (Type I) a chelating agent were prepared and evaluated towards HDA and HDN reactions. The catalysts were prepared and characterized at KTH and then activated (sulfided) and evaluated at Nynas AB. The activity of the sulfided catalysts was evaluated using surrogate mixture models containing phenanthrene (PHE) as an aromatic compound, and carbazole (CBZ) or acridine (ACR). The latter ones were representing two types of nitrogen-containing inhibitors, non-basic and basic. The activity testing was carried out in a trickle-bed microreactor during three-step experiments in the presence and absence of the organic nitrogen compounds (mode switches). During the mode switches the activity of the catalysts under varying conditions was investigated. The operating temperature of the reactor varied between 300 and 320°C under constant H2 pressure of 120 barg. The catalytic activity was positively correlated with temperature with the catalysts exhibiting lower activities at 300°C than at 320°C. It is noteworthy that the activity of all the catalysts was hindered by the presence of both nitrogen compounds at all temperatures with the basic nitrogen (ACR) being more inhibitory for both catalysts. CBZ inhibition to the HDA reactions showed reversibility, while ACR had a more permanent inhibiting effect in the case of the Type II catalyst. The results indicated that despite the preliminary assumptions, the Type I catalyst outperformed the Type II.

Neste trabalho é abordado o problema de controle e de otimização de unidades industriais de hidrotratamento de diesel (UHDT) por controladores MPC (Model Predictive Control). É apresentado um breve histórico dos controladores MPC convencionais e de horizonte infinito (IHMPC), bem como uma breve descrição do processo de Hidrotratamento de Diesel e das particularidades da aplicação do controle de processos a este tipo de planta industrial. Em seguida foi gerado, passo a passo, um algoritmo de controle que sumarizou e agregou características de vários controladores MPC disponíveis na literatura aberta, em especial os que foram desenvolvidos ao longo dos últimos anos pelo laboratório de simulação e controle da USP (LSCP), a fim de se obter um algoritmo adequado para a solução do problema de controle abordado. Em ambiente computacional de simulação, o algoritmo resultante possibilitou controlar e otimizar simultaneamente processos contínuos, sendo capaz de estabilizar a planta industrial de forma robusta e, ao mesmo tempo, aumentar a lucratividade de sua operação. Para tanto, foi desenvolvida uma função objetivo econômica que aumentou a conversão da carga bruta em produtos hidrotratados e minimizou o consumo de insumos, sendo que essa correlação foi agregada ao algoritmo de controle. As simulações permitiram que as estratégias de controle previamente discutidas pudessem ser testadas e seus resultados apresentados e debatidos. / This work addresses the control and optimization problem of industrial diesel hydrotreating units (UHDT) by MPC controllers (Model Predictive Control). It is presented a brief historical of conventional MPC controllers and infinite horizon controllers (IHMPC), as well as a brief description of the Diesel Hydrotreating process and the particulars of the application of process control for this type of industrial plant. It was then generated, step by step, one algorithm that summarized and aggregated control characteristics of various MPC controllers available in the open literature, in particular those that have been developed over the past few years by USPs laboratory of simulation and control of (LSCP), in order to obtain an algorithm suitable for solving the addressed control problem. In a computational simulation environment, the resulting algorithm allowed to simultaneously control and optimize continuous processes, being able to robustly stabilize the industrial plant and at the same time increase the profitability of its operation. For this purpose, an \"objective function\" was developed which increased the economic conversion of crude feed to hydrotreated product and minimized the consumption of raw materials, and this correlation was added to the control algorithm. The simulations allowed that the previously discussed control strategies could be tested and the results presented and discussed.

Gas-oil obtained from bitumen contains a significant amount of impurities, which are difficult to remove using a conventional alumina supported hydrotreating catalyst. Innumerable studies have been carried out to develop a highly effective hydrotreating catalyst, and among all utilizing more advanced support is considered as a better alternative. Recently, SBA-15, which is an ordered mesoporous silica support, has received importance as a catalyst support because of its excellent textural properties. However, SBA-15 lacks surface acidity and provides very low metal-support interaction. By modifying SBA-15 with zirconia, an optimum level of surface acidity and Si-Mo interaction can be achieved. Also, by doping zirconia with SBA-15, the textural properties of zirconia can be improved. Hence, a synergistic effect can be obtained while incorporating zirconia onto SBA-15 and the resulting material Zr-SBA-15 can be used as an effective support for hydrotreating catalyst. In the present study, Zr-SBA-15 supports were prepared by the post synthesis and the direct synthesis method with different zirconia loading. Zr-SBA-15 supported NiMo catalysts were prepared by incipient wetness impregnation technique. Catalysts and supports were characterized by small angle X-ray scattering (SAXS), nitrogen adsorption/desorption (BET), powder X-ray diffraction (XRD), transmission electron spectroscopy (TEM), scanning electron microscopy (SEM), and Raman spectroscopy methods.<p> Characterization of support confirmed that the zirconia was successfully incorporated in a mesoporous SBA-15 structure without significantly changing the textural properties of SBA-15. The performance of the Zr-SBA-15 supported NiMo catalysts was evaluated based on hydrodesulfurization and hydrodenitrogenation activities exhibited during hydrotreating of heavy gas oil derived from Athabasca bitumen at industrial operating condition (temperature 375-395 °C, pressure 8.9 MPa, LHSV 1.0 hr-1 and gas/oil ratio 600 Nm3/m3). The comparison of catalytic activities showed that the NiMo catalysts supported on Zr-SBA-15, prepared by direct and post synthesis method exhibited higher hydrotreating activity compared to SBA-15 supported catalyst. NiMo catalyst supported on Zr-SBA-15 with 23 wt% of ZrO2 loading, prepared by post synthesis method showed the highest activity among all the catalysts.<p> After determining the best support, the optimum catalyst metal loadings on the Zr-SBA-15 support was found to be 17 wt% of Mo and 3.4 wt% of Ni. This catalyst also showed higher activity in mass basis for the hydrotreating of heavy gas oil compared to that of commercial hydrotreating catalyst.<p> A kinetic study was performed on the optimum NiMo/Zr-SBA-15 catalyst to predict its HDS and HDN activities while varying the parameters of temperature, liquid hourly space velocity (LHSV), pressure and gas-to-oil ratio. Rate expressions were developed using Power Law and Langmuir-Hinshelwood model to predict the behavior of both the HDS and HDN reactions. Power law models were best fit with reaction orders of 1.8 and 1.3, and activation energies of 115 kJ/mol and 121 kJ/mol, for HDS and HDN reactions, respectively. The activation energies calculated using Langmuir-Hinshelwood model considering H2S inhibition were found to be 122 kJ/mol and 138 kJ/mol, for HDS and HDN reactions, respectively.

New catalyst development for the hydrotreating process, employing functionalized mesoporous carbon (mC) support is studied. mC support was prepared by the volume templating of alkali modified SBA-15 using sucrose as the carbon source and then functionalized using nitric acid of various concentrations (upto 8M HNO3). A series of NiMo catalysts (12% Mo and 2.4% Ni) were prepared using these functionalized mC supports. The supports and catalysts were characterized by N2 physisorption, SAXS, XRD, FTIR, TGA, SEM, TEM, H2-TPR and HRTEM. SAXS results indicated mild reduction in ordered structure of mesoporous carbons after functionalization. N2 physisorption analysis indicated progressive reduction in surface area and pore volume with the increase in nitric acid concentration. Enhancement of surface functional groups and acidity after functionalization were observed through FTIR spectroscopy and Boehm titration. SEM images showed the retention of needle like morphology in all functionalized carbon supports. TEM images showed that the increase in nitric acid concentration causes excessive etching, resulting in the reduction of ordered structure of functionalized mesoporous carbons. Hydrotreating study of these NiMo/mC catalysts were carried out under industrial operating conditions in a laboratory scale trickle bed reactor using coker light gas oil derived from Athabasca bitumen as feedstock. NiMo catalyst supported on 6M acid treated mC (i.e. NiMo/mC-6M) showed the highest activity due to higher surface functional groups, higher acidity and better textural properties. The HDS and HDN activities of NiMo/mC-6M catalyst were higher than that of NiMo/ã-Al2O3 catalyst owing to lower support metal interaction (SMI), higher surface area and effective functionalization. Using the mC-6M support, NiMo catalysts with different metal loading (12 27% Mo, 2.4 to 5.4% Ni) were prepared and characterized. Hydrotreating activity study of these catalysts indicated that the catalyst with 22% Mo and 2.9% Ni loading was the optimum catalyst on 6M functionalized mC support. Higher metal loading (>22%Mo) led to excessive pore blockage and improper metal dispersion resulting in decreased activity. Kinetic study of the optimum catalyst was carried out by varying temperature (330°C to 370°C), gas-to-oil ratio (400 1000 Nm3/m3), LHSV (1.0 to 2.5 hr-1) and pressure (7.8 to 9.8 MPa) and the data was fitted by non-linear regression method using power law model. The calculated reaction orders and activation energies were 2.8, 1.5 and 189 KJ/mol, 98.9 KJ/mol for HDS and HDN, respectively. The results of HRTEM and H2-TPR indicated lower SMI in mC supported catalyst resulting in the generation of qualitatively Type-II like NiMoS phase on functionalized mC supports, which is considered to be very active for hydrotreating. The hydrotreating activity of the optimum catalyst was higher than that of commercial catalyst (supported on ã-Al2O3). Long term deactivation experiment carried out over a total period of 10 weeks confirmed the durability of NiMo/mC catalyst for the duration of operation. This study reveals the immense capability of functionalized mC supports to become the potential alternative catalyst support to conventional ã-Al2O3 for the hydrotreating of gas oil feedstocks.

Nowadays, computers are extensively used in engineering modeling and simulation fields in many different ways, one of which is in chemical engineering. Simulation and modeling of a chemical process plant and the sizing of the equipment with the assistance of computers, is of special interests to process engineers and investors. This is due to the ability of high speed computers, which make millions of mathematical calculations in less than a second associated with the new powerful software that make the engineering calculations more reliable and precise by making very fast iterations in thermodynamics, heat and mass transfer calculations. This combination of new technological hardware and developed software enables process engineers to deal with simulation, design, optimization, control, analysis etc. of complex plants, e.g. refinery and petrochemical plants, reliably and satisfactorily. The main chemical process simulators used for static and dynamic simulations are ASPEN PLUS, ASPEN HYSYS, PRO II, and CHEMCAD. The basic design concepts of all simulators are the same and one can fairly use all simulators if one is expert in any of them. Hydrogenation process is an example of the complex plants, to which a special attention is made by process designers and manufacturers. This process is used for upgrading of hydrocarbon feeds containing sulfur, nitrogen and/or other unsaturated hydrocarbon compounds. In oil and gas refineries, the product of steam cracking cuts, which is valuable, may be contaminated by these unwanted components and thus there is a need to remove those pollutants in downstream of the process. Hydrogenation is also used to increase the octane number of gasoline and gas oil. Sulfur, nitrogen and oxygen compounds and other unsaturated hydrocarbons are undesired components causing environmental issues, production of by-products, poisoning the catalysts and corrosion of the equipment. The unsaturated C=C double bonds in dioleffinic and alkenyl aromatics compounds, on the other hand, cause unwanted polymerization reactions due to having the functionality equal to or greater than 2. Hydrogenation process of the undesired components will remove those impurities and/or increase the octane number of aforementioned hydrocarbons. This process is sometimes referred to as “hydrotreating”; however, “upgrader” is a general word and is, of course, of more interest. In this thesis, a hydrogenation process plant was designed on the basis of the chemistry of hydrocarbons, hydrogenation reaction mechanism, detailed study of thermodynamics and kinetics and then a steady-state simulation and design of the process is carried out by ASPEN HYSYS 2006 followed by design evaluation and some modifications and conclusions. Hydrogenation reaction has a complicated mechanism. It has been subjected to hot and controversial debates over decades. Many kinetic data are available, which contradict one another. Among them, some of the experimental researches utilize good assumptions in order to simplify the mechanism so that a “Kinetic Reaction” modeling can be employed. This thesis takes the benefit of such research works and applies some conditions to approve the validity of those assumptions. On the basis of this detailed study of reaction modeling and kinetic data, a hydrogenation plant was designed to produce and purify over 98 million kilograms of different products; e.g. Benzene, Toluene, Iso-octane etc. with fairly high purity.

Nowadays, computers are extensively used in engineering modeling and simulation fields in many different ways, one of which is in chemical engineering. Simulation and modeling of a chemical process plant and the sizing of the equipment with the assistance of computers, is of special interests to process engineers and investors. This is due to the ability of high speed computers, which make millions of mathematical calculations in less than a second associated with the new powerful software that make the engineering calculations more reliable and precise by making very fast iterations in thermodynamics, heat and mass transfer calculations. This combination of new technological hardware and developed software enables process engineers to deal with simulation, design, optimization, control, analysis etc. of complex plants, e.g. refinery and petrochemical plants, reliably and satisfactorily. The main chemical process simulators used for static and dynamic simulations are ASPEN PLUS, ASPEN HYSYS, PRO II, and CHEMCAD. The basic design concepts of all simulators are the same and one can fairly use all simulators if one is expert in any of them. Hydrogenation process is an example of the complex plants, to which a special attention is made by process designers and manufacturers. This process is used for upgrading of hydrocarbon feeds containing sulfur, nitrogen and/or other unsaturated hydrocarbon compounds. In oil and gas refineries, the product of steam cracking cuts, which is valuable, may be contaminated by these unwanted components and thus there is a need to remove those pollutants in downstream of the process. Hydrogenation is also used to increase the octane number of gasoline and gas oil. Sulfur, nitrogen and oxygen compounds and other unsaturated hydrocarbons are undesired components causing environmental issues, production of by-products, poisoning the catalysts and corrosion of the equipment. The unsaturated C=C double bonds in dioleffinic and alkenyl aromatics compounds, on the other hand, cause unwanted polymerization reactions due to having the functionality equal to or greater than 2. Hydrogenation process of the undesired components will remove those impurities and/or increase the octane number of aforementioned hydrocarbons. This process is sometimes referred to as “hydrotreating”; however, “upgrader” is a general word and is, of course, of more interest. In this thesis, a hydrogenation process plant was designed on the basis of the chemistry of hydrocarbons, hydrogenation reaction mechanism, detailed study of thermodynamics and kinetics and then a steady-state simulation and design of the process is carried out by ASPEN HYSYS 2006 followed by design evaluation and some modifications and conclusions. Hydrogenation reaction has a complicated mechanism. It has been subjected to hot and controversial debates over decades. Many kinetic data are available, which contradict one another. Among them, some of the experimental researches utilize good assumptions in order to simplify the mechanism so that a “Kinetic Reaction” modeling can be employed. This thesis takes the benefit of such research works and applies some conditions to approve the validity of those assumptions. On the basis of this detailed study of reaction modeling and kinetic data, a hydrogenation plant was designed to produce and purify over 98 million kilograms of different products; e.g. Benzene, Toluene, Iso-octane etc. with fairly high purity.

Gas-oil obtained from bitumen contains a significant amount of impurities, which are difficult to remove using a conventional alumina supported hydrotreating catalyst. Innumerable studies have been carried out to develop a highly effective hydrotreating catalyst, and among all utilizing more advanced support is considered as a better alternative. Recently, SBA-15, which is an ordered mesoporous silica support, has received importance as a catalyst support because of its excellent textural properties. However, SBA-15 lacks surface acidity and provides very low metal-support interaction. By modifying SBA-15 with zirconia, an optimum level of surface acidity and Si-Mo interaction can be achieved. Also, by doping zirconia with SBA-15, the textural properties of zirconia can be improved. Hence, a synergistic effect can be obtained while incorporating zirconia onto SBA-15 and the resulting material Zr-SBA-15 can be used as an effective support for hydrotreating catalyst. In the present study, Zr-SBA-15 supports were prepared by the post synthesis and the direct synthesis method with different zirconia loading. Zr-SBA-15 supported NiMo catalysts were prepared by incipient wetness impregnation technique. Catalysts and supports were characterized by small angle X-ray scattering (SAXS), nitrogen adsorption/desorption (BET), powder X-ray diffraction (XRD), transmission electron spectroscopy (TEM), scanning electron microscopy (SEM), and Raman spectroscopy methods.<p> Characterization of support confirmed that the zirconia was successfully incorporated in a mesoporous SBA-15 structure without significantly changing the textural properties of SBA-15. The performance of the Zr-SBA-15 supported NiMo catalysts was evaluated based on hydrodesulfurization and hydrodenitrogenation activities exhibited during hydrotreating of heavy gas oil derived from Athabasca bitumen at industrial operating condition (temperature 375-395 °C, pressure 8.9 MPa, LHSV 1.0 hr-1 and gas/oil ratio 600 Nm3/m3). The comparison of catalytic activities showed that the NiMo catalysts supported on Zr-SBA-15, prepared by direct and post synthesis method exhibited higher hydrotreating activity compared to SBA-15 supported catalyst. NiMo catalyst supported on Zr-SBA-15 with 23 wt% of ZrO2 loading, prepared by post synthesis method showed the highest activity among all the catalysts.<p> After determining the best support, the optimum catalyst metal loadings on the Zr-SBA-15 support was found to be 17 wt% of Mo and 3.4 wt% of Ni. This catalyst also showed higher activity in mass basis for the hydrotreating of heavy gas oil compared to that of commercial hydrotreating catalyst.<p> A kinetic study was performed on the optimum NiMo/Zr-SBA-15 catalyst to predict its HDS and HDN activities while varying the parameters of temperature, liquid hourly space velocity (LHSV), pressure and gas-to-oil ratio. Rate expressions were developed using Power Law and Langmuir-Hinshelwood model to predict the behavior of both the HDS and HDN reactions. Power law models were best fit with reaction orders of 1.8 and 1.3, and activation energies of 115 kJ/mol and 121 kJ/mol, for HDS and HDN reactions, respectively. The activation energies calculated using Langmuir-Hinshelwood model considering H2S inhibition were found to be 122 kJ/mol and 138 kJ/mol, for HDS and HDN reactions, respectively.