The impact of H2 partial pressure (H2 pp) during the hydrotreating of heavy gas oil, derived from Athabasca bitumen, over commercial NiMo/¥ã-Al2O3 catalyst was studied in a micro-trickle bed reactor. The experimental conditions were varied as follows: temperature: 360 to 400¨¬C, pressure: 7 to 11 MPa, gas/oil ratio: 400 to 1270 mL/mL, H2 purity range of 0 to 100 vol. % (with the rest either CH4 or He), and LHSV range of 0.65 to 2 h-1. The two main objectives of the project were to study the nature of the dependence of H2 pp on temperature, pressure, gas/oil ratio, LHSV (Liquid Hourly Space Velocity), and H2 purity. The project was divided into three phases: in phase one the effect of H2 purity on hydrotreating of heavy gas oil (HGO) was studied, in phase two the nature of H2 pp dependency and the effect of H2 pp on hydrotreating of HGO was investigated, and in phase three kinetic studies were carried out using different kinetic models.<p> The objective of phase one was to study the effect of hydrogen purity on hydrotreating of HGO was studied in a trickle bed reactor over a commercial Ni−Mo/¥ã-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 purities ranging from 75 to 95% (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/¥ã-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 were studied. Also determined were cetane index, density, aniline point, diesel index, and fractional distribution of the products.<p> The main objective of phase two was to study the effects of H2 pp on hydrotreating conversions, feed vaporization, H2 dissolution, and H2 consumption were studied. The results show that HDN and HDA are significantly more affected by H2 partial pressure than HDS; with the HDN being the most affected. For instance as the inlet H2 partial pressure was increased from 4.6 to 8.9 MPa HDS, HDN, and HDA conversions increased for 94.9%, 55.1%, and 46.0% to 96.7%, 83.9%, and 58.0% , respectively. Moreover, it was observed that H2 dissolution and H2 consumption increased with increasing H2 pp. No clear trend was observed for the effect of H2 pp on feed vaporization.<p> In phase three the kinetics of HDS, HDN, and HDA were studied. The power law, multi-parameter, and Langmuir - Hinshelwood type models were used to fit the data. The prediction capacities of the resulting models were tested. It was determined that, while multi-parameter model yielded better prediction, L-H had an advantage in that it took a lesser number of experimental data to determine its parameters. Kinetic fitting of the data to a pseudo-first-order power law model suggested that conclusions on the effect of H2 pp on hydrotreating activities could be equally drawn from either inlet or outlet hydrogen partial pressure. However, from the catalyst deactivation standpoint, it is recommended that such conclusions are drawn from the outlet H2 partial pressure, since it is the reactor point with the lowest hydrogen partial pressure.

The impact of H2 partial pressure (H2 pp) during the hydrotreating of heavy gas oil, derived from Athabasca bitumen, over commercial NiMo/¥ã-Al2O3 catalyst was studied in a micro-trickle bed reactor. The experimental conditions were varied as follows: temperature: 360 to 400¨¬C, pressure: 7 to 11 MPa, gas/oil ratio: 400 to 1270 mL/mL, H2 purity range of 0 to 100 vol. % (with the rest either CH4 or He), and LHSV range of 0.65 to 2 h-1. The two main objectives of the project were to study the nature of the dependence of H2 pp on temperature, pressure, gas/oil ratio, LHSV (Liquid Hourly Space Velocity), and H2 purity. The project was divided into three phases: in phase one the effect of H2 purity on hydrotreating of heavy gas oil (HGO) was studied, in phase two the nature of H2 pp dependency and the effect of H2 pp on hydrotreating of HGO was investigated, and in phase three kinetic studies were carried out using different kinetic models.<p> The objective of phase one was to study the effect of hydrogen purity on hydrotreating of HGO was studied in a trickle bed reactor over a commercial Ni−Mo/¥ã-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 purities ranging from 75 to 95% (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/¥ã-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 were studied. Also determined were cetane index, density, aniline point, diesel index, and fractional distribution of the products.<p> The main objective of phase two was to study the effects of H2 pp on hydrotreating conversions, feed vaporization, H2 dissolution, and H2 consumption were studied. The results show that HDN and HDA are significantly more affected by H2 partial pressure than HDS; with the HDN being the most affected. For instance as the inlet H2 partial pressure was increased from 4.6 to 8.9 MPa HDS, HDN, and HDA conversions increased for 94.9%, 55.1%, and 46.0% to 96.7%, 83.9%, and 58.0% , respectively. Moreover, it was observed that H2 dissolution and H2 consumption increased with increasing H2 pp. No clear trend was observed for the effect of H2 pp on feed vaporization.<p> In phase three the kinetics of HDS, HDN, and HDA were studied. The power law, multi-parameter, and Langmuir - Hinshelwood type models were used to fit the data. The prediction capacities of the resulting models were tested. It was determined that, while multi-parameter model yielded better prediction, L-H had an advantage in that it took a lesser number of experimental data to determine its parameters. Kinetic fitting of the data to a pseudo-first-order power law model suggested that conclusions on the effect of H2 pp on hydrotreating activities could be equally drawn from either inlet or outlet hydrogen partial pressure. However, from the catalyst deactivation standpoint, it is recommended that such conclusions are drawn from the outlet H2 partial pressure, since it is the reactor point with the lowest hydrogen partial pressure.

Bitumen-derived heavy gas oil contains large amounts of sulfur (~4.0 wt.%) and nitrogen (~0.4 wt.%), which need to be lowered before it becomes suitable as a feedstock for refineries. The most widely used upgrading process is hydrotreating, and the conventional catalyst used for hydrotreating is Ni or Co and Mo or W supported on γ-Al2O3. Additionally, environmentally driven regulations impose strict limits on sulfur and nitrogen levels in transportation fuels. Therefore, the main focus of this work was to enhance the activity of a NiMo supported catalyst through its modification and to improve its selectivity to removal of bulky sulfur- and nitrogen-containing compounds from heavy gas oil under industrial hydrotreating conditions. This work was divided into four phases, and this thesis summarizes the research outcomes of each phase. The first phase examined the effects of chelating ligands, specifically, ethylenediaminetetraacetic acid (EDTA), on hydrotreating activity and the sulfidation mechanism. EDTA was seen to have a beneficial effect on hydrotreating activity. Detailed mechanistic aspects of interactions between support and EDTA, EDTA and metallic species, support and metal, support and active phase, and metallic species and metallic species at different reaction conditions, were also studied. Characterization by XANES revealed that the presence of a chelating agent delayed nickel sulfidation, which was the main cause of improvement in hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) activities. It also showed that EDTA plays a role in redistribution of active phases during sulfidation and favors the formation of octahedral molybdenum oxides. The second phase studied the effects of support modification and combinations of different supports and EDTA. In this phase, several mesoporous materials, including M-SBA-15 (M= Al, Ti and Zr), mesoporous mixed metal oxides (TiO2-Al2O3, ZrO2-Al2O3 andSnO2-Al2O3) and mesoporous metal oxides (ZrO2, Al2O3), were synthesized and used as support materials for a NiMo catalyst. NiMo/M-SBA-15 catalysts showed higher HDS and HDN activities and, the increase in activity is attributed to incorporation of heteroatoms in an SBA-15 matrix, which resulted in increase in metal support interaction, acidic strength and dispersion of active metals. The addition of EDTA to these catalysts helps in the formation of octahedral molybdenum oxide, which are easily reducible during sulfidation. This is evident from the XANES Mo LIII-edge study of the oxide catalysts. The increase in hydrodenitrogenation (HDN), hydrodesulfurization (HDS) and hydrodearomatization (HDA) activities as compared to that shown by the NiMo/γ-Al2O3 catalyst were also observed on addition of EDTA in large-pore, high-surface-area mesoporous zirconia supported NiMo catalysts. The incorporation of different metal oxides in alumina, as in the case of mixed metal oxides, resulted in a change in acidic strength and metal support interactions. It was observed with acridine-FTIR analysis that the catalysts with higher acidic strength tightly held acridine at high temperatures. This implies that catalysts with higher acidity are prone to inhibition by nitrogen-containing compounds present in feed, which will affect catalytic activity. The HDS and HDN activities for hydrotreating of heavy gas oil suggest that mesoporous alumina and titania-alumina supported catalysts perform better as compared to the conventional NiMo/γ-Al2O3 catalyst. Therefore, the effects of EDTA to Ni molar ratio (EDTA/Ni = 0 to 2) on the activities of the NiMo/MesoAl2O3 and NiMo/MesoTiO2-Al2O3 catalysts were studied, and EDTA was observed to have a negative impact on catalytic activity for these catalysts. This is attributed to a decrease in the active metal dispersion in these catalysts caused by the addition of EDTA. The catalysts NiMo/MesoAl2O3 and NiMo/MesoTiO2-Al2O3 without EDTA showed high active metal dispersion due to their high surface area and ordered structure. The third phase studied the combined effects of phosphorus and EDTA on the hydrotreating activity of NiMo supported catalysts. The effects of method of phosphorus addition (sequential and co-impregnation method) were also studied. When phosphorus was added using a co-impregnation method, as in the catalyst NiMoP/MesoAl2O3(CI), an increase in HDN, HDA and HDS activities was observed. However, the catalysts containing both EDTA and phosphorus showed a decrease in HDS and HDN activities. The fourth phase included a kinetic study using the Power Law and L-H models. The catalyst, NiMoP/mesoAl2O3(CI), was found to have higher HDN and HDS activities as compared to a conventional γ-Al2O3 supported catalyst containing phosphorus.

Thesis (Ph. D.)--University of Texas at El Paso, 2009. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

Four nickel-molybdenum catalysts were synthesized on gamma alumina with higher surface area and on NiMo catalyst was prepared using gamma alumina with lower surface area. Catalysts with higher-surface-area support were prepared by co-impregnation, sequential impregnation and adding phosphorous. Theses catalysts were calcined at 500  ͦC. Effect of higher calcination temperature was investigated by preparation of one catalyst calcined at 700 ͦC. Catalysts were thoroughly characterized via four characterization techniques. The hydrotreating activity of three catalysts was carried out in a micro reactor at high pressure and three different temperatures with Nynas vacuum middle distillate. Prior to the test, sulfiding was carried out to activate the catalysts. Hydrotreated-oil samples as products were analyzed to evaluate the activity and conversion of the catalyst. Also, the spent catalysts were characterized to evaluate the surface area characteristics and deactivation of catalysts. Addition of phosphorous to NiMo/gamma-Al2O3 improved the interaction between the metals and the support as well as reduced the coke formation as observed in scanning electron microscopy micrographs.

Multi-walled carbon nanotubes (MWCNTs) are a potential alternative to commonly used catalyst support structures in hydrotreating processes. Synthesis of MWCNTs with specific pore diameters can be achieved by chemical vapor deposition (CVD) of a carbon source onto an anodic aluminum oxide (AAO) template. AAO films consist of pore channels in a uniform hexagonal arrangement that run parallel to the surface of the film. These films are created by the passivation of an aluminum anode within an electrolysis cell consisting of certain weak acid electrolytes. Changing the concentration of the electrolyte (oxalic acid) and the electrical potential of the electrolysis cell altered the pore channel diameter of these AAO films. Controlling the pore diameter of these templates enabled the pore diameter of MWCNTs synthesized by CVD to be controlled as well. The produced MWCNTs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Raman spectroscopy, and N2 adsorption analysis. Anodizing conditions of 0.40 M oxalic acid concentration and 40.0 V maximum anodizing potential were found to produce AAO films that resulted in MWCNTs with optimum surface characteristics for a catalyst support application. CVD parameter values of 650°C reaction temperature and 8.00 mL/(min·g) C2H2-to-AAO ratio were found to produce the highest yield of MWCNT product.<p> The MWCNTs were synthesized for the purpose of supporting hydroprocessing catalysts, with several grades of NiMo/MWCNT sulfide catalysts being prepared to determine the optimum pore size. These catalysts were characterized by techniques of TEM, CO chemisorption, N2 adsorption, and H2 temperature programmed reduction (TPR). A MWCNT grade with 67 nm inner diameters (found from TEM analysis) was found to offer the best hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) activities for the treatment of coker light gas oil (CLGO). After determining the most suitable pore diameter, the optimum catalyst metal loadings were found to be 2.5 wt.% for Ni and 19.5 wt.% for Mo. The optimum catalyst was found to offer HDS conversions of 90.5%, 84.4%, and 73.5% with HDN conversions of 75.9%, 65.8%, and 55.3% for temperatures of 370°C, 350°C, and 330°C, respectively. An equal mass loading of commercial NiMo/ã-Al2O3 catalyst offered HDS conversions of 91.2%, 77.9%, and 58.5% with HDN conversions of 71.4%, 53.2%, and 31.3% for temperatures of 370°C, 350°C, and 330°C, respectively.<p> A kinetic study was performed on the optimum NiMo/MWCNT catalyst to help predict its HDS and HDN activities while varying the parameters of temperature, liquid hourly space velocity (LHSV), pressure, and gas-to-oil flow rate ratio. Rate expressions were then developed to predict the behavior of both the HDS and HDN reactions. Power law models were best fit with reaction orders of 2.6 and 1.2, and activation energies of 161 kJ/mol and 82.3 kJ/mol, for the HDS and HDN reactions, respectively. Generalized Langmuir-Hinshelwood models were found to have reaction orders of 3.0 and 1.5, and activation energies of 155 kJ/mol and 42.3 kJ/mol, for the HDS and HDN reactions, respectively.

The pore diameter of a catalyst support controls the diffusion of reactant molecules to the catalytic active sites; thus, affecting the rates and conversions of the hydrotreating reactions. Desirable textural properties of SBA-15 makes it a potential alternative to the conventionally used γ-Al2O3 support due to the fact that its pore size can be manipulated via controlling the synthesis parameters, while maintaining relatively high surface area. Larger pore diameter SBA-15 supports may facilitate the diffusion of bulky molecules as that of the asphaltenes present in the heavy petroleum fractions, making it a potential catalyst support for hydrotreating operations. Considering the very sour nature of Canadas bitumen with high sulfur contents in the range of 2-6 wt %, the appreciably high sulfur contents particularly present in Athabasca derived heavy gas oils (about 4 wt % sulfur), the rising demand for cleaner fuels, and also the increasing stringency on environmental standards, the need for novel and improved hydrotreating catalysts cannot be overemphasized. By varying the molar ratio of hexane to ammonium fluoride, the pore channels of SBA-15 could be varied. Controlling the pore diameter of these supports via micelle swelling facilitated the production of larger pore diameter SBA-15-supported catalysts. In this project, four mesoporous silica SBA-15 catalyst supports with pore diameters in the range of 5-20 nm were synthesized in the preliminary phase using hexane as the micelle swelling agent and subsequently utilized for the loading of 2 wt.% Fe and 15 wt.% W catalyst metals, respectively. The hexagonal mesoscopic structure of these materials were characterized using powder small-angle X-ray scattering (SAXS), N2 adsorption-desorption isotherms, TEM and SEM images. Powder XRD analysis evidenced inhomogeneous metal dispersion on the largest pore diameter catalyst. An optimum pore diameter of 10 nm was found for Cat-B and subsequently used to obtain the optimum Fe and W loadings required to achieve the best hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) activities. The optimum catalyst was found to be Cat-H with metal loadings of 3 wt.% Fe and 30 wt.% W. At these loadings and temperatures of 375°C, 388°C, and 400°C, HDS activities of 53.4%, 64.1%, and 73.3% with corresponding HDN activities of 21.9%, 26.2%, and 38.3%, respectively, were recorded. Catalytic performance evaluations conducted on equal mass loading using a reference commercial γ-Al2O3-supported FeW catalyst offered HDS activities of 69.3%, 80.4%, and 89.1%, with corresponding HDN activities of 16.4%, 32.4%, and 49.3% at the same temperatures studied. However, no significant changes in HDS and HDN activities were observed for similar evaluations on volume percent metals loading basis. Kinetic studies performed with the optimum FeW/SBA-15 catalyst suggested activation energies of 147.2 and 150.6 kJ/mol for HDS and HDN, respectively, by the Langmuir-Hinshelwoods model. Similar results were predicted by the Power Law and Multi-parameter models for HDS (129.6 and 126.7 kJ/mol, respectively), which does not conclusively make the latter model clearly stand out as the best. Data fitting by the Power Law suggested reaction orders of 2 and 1.5 for HDS and HDN, which seem to be consistent for the hydrotreatment of heavy gas oil. Finally, a long-term deactivation study spanning a period of 60 days time-on-stream showed the optimum catalyst to be stable under hydrotreating experiments conducted in a downward flow micro-trickle bed reactor at temperature, pressure, liquid hourly space velocity (LHSV), and gas/oil ratio of 375400˚C, 8.8 MPa, 1h-1, and 600 mL/mL (at STP), respectively.

Multi-walled carbon nanotubes (MWCNTs) are a potential alternative to commonly used catalyst support structures in hydrotreating processes. Synthesis of MWCNTs with specific pore diameters can be achieved by chemical vapor deposition (CVD) of a carbon source onto an anodic aluminum oxide (AAO) template. AAO films consist of pore channels in a uniform hexagonal arrangement that run parallel to the surface of the film. These films are created by the passivation of an aluminum anode within an electrolysis cell consisting of certain weak acid electrolytes. Changing the concentration of the electrolyte (oxalic acid) and the electrical potential of the electrolysis cell altered the pore channel diameter of these AAO films. Controlling the pore diameter of these templates enabled the pore diameter of MWCNTs synthesized by CVD to be controlled as well. The produced MWCNTs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Raman spectroscopy, and N2 adsorption analysis. Anodizing conditions of 0.40 M oxalic acid concentration and 40.0 V maximum anodizing potential were found to produce AAO films that resulted in MWCNTs with optimum surface characteristics for a catalyst support application. CVD parameter values of 650°C reaction temperature and 8.00 mL/(min·g) C2H2-to-AAO ratio were found to produce the highest yield of MWCNT product.<p> The MWCNTs were synthesized for the purpose of supporting hydroprocessing catalysts, with several grades of NiMo/MWCNT sulfide catalysts being prepared to determine the optimum pore size. These catalysts were characterized by techniques of TEM, CO chemisorption, N2 adsorption, and H2 temperature programmed reduction (TPR). A MWCNT grade with 67 nm inner diameters (found from TEM analysis) was found to offer the best hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) activities for the treatment of coker light gas oil (CLGO). After determining the most suitable pore diameter, the optimum catalyst metal loadings were found to be 2.5 wt.% for Ni and 19.5 wt.% for Mo. The optimum catalyst was found to offer HDS conversions of 90.5%, 84.4%, and 73.5% with HDN conversions of 75.9%, 65.8%, and 55.3% for temperatures of 370°C, 350°C, and 330°C, respectively. An equal mass loading of commercial NiMo/ã-Al2O3 catalyst offered HDS conversions of 91.2%, 77.9%, and 58.5% with HDN conversions of 71.4%, 53.2%, and 31.3% for temperatures of 370°C, 350°C, and 330°C, respectively.<p> A kinetic study was performed on the optimum NiMo/MWCNT catalyst to help predict its HDS and HDN activities while varying the parameters of temperature, liquid hourly space velocity (LHSV), pressure, and gas-to-oil flow rate ratio. Rate expressions were then developed to predict the behavior of both the HDS and HDN reactions. Power law models were best fit with reaction orders of 2.6 and 1.2, and activation energies of 161 kJ/mol and 82.3 kJ/mol, for the HDS and HDN reactions, respectively. Generalized Langmuir-Hinshelwood models were found to have reaction orders of 3.0 and 1.5, and activation energies of 155 kJ/mol and 42.3 kJ/mol, for the HDS and HDN reactions, respectively.

The pore diameter of a catalyst support controls the diffusion of reactant molecules to the catalytic active sites; thus, affecting the rates and conversions of the hydrotreating reactions. Desirable textural properties of SBA-15 makes it a potential alternative to the conventionally used γ-Al2O3 support due to the fact that its pore size can be manipulated via controlling the synthesis parameters, while maintaining relatively high surface area. Larger pore diameter SBA-15 supports may facilitate the diffusion of bulky molecules as that of the asphaltenes present in the heavy petroleum fractions, making it a potential catalyst support for hydrotreating operations. Considering the very sour nature of Canadas bitumen with high sulfur contents in the range of 2-6 wt %, the appreciably high sulfur contents particularly present in Athabasca derived heavy gas oils (about 4 wt % sulfur), the rising demand for cleaner fuels, and also the increasing stringency on environmental standards, the need for novel and improved hydrotreating catalysts cannot be overemphasized. By varying the molar ratio of hexane to ammonium fluoride, the pore channels of SBA-15 could be varied. Controlling the pore diameter of these supports via micelle swelling facilitated the production of larger pore diameter SBA-15-supported catalysts. In this project, four mesoporous silica SBA-15 catalyst supports with pore diameters in the range of 5-20 nm were synthesized in the preliminary phase using hexane as the micelle swelling agent and subsequently utilized for the loading of 2 wt.% Fe and 15 wt.% W catalyst metals, respectively. The hexagonal mesoscopic structure of these materials were characterized using powder small-angle X-ray scattering (SAXS), N2 adsorption-desorption isotherms, TEM and SEM images. Powder XRD analysis evidenced inhomogeneous metal dispersion on the largest pore diameter catalyst. An optimum pore diameter of 10 nm was found for Cat-B and subsequently used to obtain the optimum Fe and W loadings required to achieve the best hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) activities. The optimum catalyst was found to be Cat-H with metal loadings of 3 wt.% Fe and 30 wt.% W. At these loadings and temperatures of 375°C, 388°C, and 400°C, HDS activities of 53.4%, 64.1%, and 73.3% with corresponding HDN activities of 21.9%, 26.2%, and 38.3%, respectively, were recorded. Catalytic performance evaluations conducted on equal mass loading using a reference commercial γ-Al2O3-supported FeW catalyst offered HDS activities of 69.3%, 80.4%, and 89.1%, with corresponding HDN activities of 16.4%, 32.4%, and 49.3% at the same temperatures studied. However, no significant changes in HDS and HDN activities were observed for similar evaluations on volume percent metals loading basis. Kinetic studies performed with the optimum FeW/SBA-15 catalyst suggested activation energies of 147.2 and 150.6 kJ/mol for HDS and HDN, respectively, by the Langmuir-Hinshelwoods model. Similar results were predicted by the Power Law and Multi-parameter models for HDS (129.6 and 126.7 kJ/mol, respectively), which does not conclusively make the latter model clearly stand out as the best. Data fitting by the Power Law suggested reaction orders of 2 and 1.5 for HDS and HDN, which seem to be consistent for the hydrotreatment of heavy gas oil. Finally, a long-term deactivation study spanning a period of 60 days time-on-stream showed the optimum catalyst to be stable under hydrotreating experiments conducted in a downward flow micro-trickle bed reactor at temperature, pressure, liquid hourly space velocity (LHSV), and gas/oil ratio of 375400˚C, 8.8 MPa, 1h-1, and 600 mL/mL (at STP), respectively.

Nickel aluminate reduced in hydrogen for 3 h at 500ºC was studied for desulfurization of model fuel comprised of dodecane spiked with benzothiophene (300 ppmw S). The nanopowder adsorbent was synthesized using combustion chemical vapor condensation, which created nickel aluminate with a BET specific surface area of 57.8 m2/g and average particle size of 11.7 nm. The nickel aluminate adsorbent removed 23 µmol of sulfur gram at breakthrough (<15 ppmw S). Regeneration by further heat treatment in hydrogen or air recovered 25% and 40% of original capacity, respectively.