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Applied Catalysis A, General (v.339, #2)
Studies on vanadium-doped iron phosphate catalysts for the ammoxidation of methylpyrazine by P. Nagaraju; N. Lingaiah; M. Balaraju; P.S. Sai Prasad (pp. 99-107).
Bulk and vanadium-doped iron phosphate catalysts were prepared and studied for the vapor phase ammoxidation of 2-methyl pyrazine. The vanadium-doped catalyst showed better activity than bulk catalysts as the vanadium doping leads to formation of quartz-type iron phosphate with additional phases of V2O5 and (VO)2P2O7.▪Vanadium-doped iron phosphates (with 1, 3 and 5wt.% V) were prepared and characterized by XRD, FTIR, UV-DRS, TPR, TEM, Laser Raman, XPS, and potentiometric titration techniques. Both undoped and V-doped catalysts displayed predominant formation of quartz type iron phosphate. In addition, the V-doped catalysts indicated formation of two more phases: V2O5 and (VO)2P2O7. The nitrile yield of V-doped catalysts in the ammoxidation of methyl pyrazine to cyanopyrazine were found to be higher than the yield of bulk FePO4, V2O5 and (VO)2P2O7. The increase in the redox property of the catalyst, as obtained by benzyl alcohol oxidation to benzaldehyde, was found to be the reason for enhanced activity. The variation of V-content in FePO4 revealed that the catalyst reached its optimum activity at 3wt.% V. However, the acid strength of the V-doped catalysts decreased with V-content and this reflected in their cyanopyrazine selectivity.
Keywords: Iron phosphate; Vanadium doping; Ammoxidation; Methylpyrazine
Influence of the synthesis procedure on the properties and reactivity of nanostructured ceria powders by Jacopo Rebellato; Marta Maria Natile; Antonella Glisenti (pp. 108-120).
Nanosized ceria was synthesized using three different preparation procedures: (1) precipitation from a basic solution of cerium nitrate containing H2O2 at 273K; (2) Marcilly method (3) microemulsion method. The samples were characterized by means of XRD, TEM, XPS, DRIFT and thermal analysis. The influence of the preparation procedure on properties and reactivity was investigated.▪Nanosized cerium (IV) oxide powder was synthesized using three different preparation procedures: (1) precipitation from a basic solution of cerium nitrate containing H2O2 at 273K; (2) Marcilly method and (3) microemulsion method. The X-ray diffraction (XRD) patterns of the as-prepared samples obtained, respectively, by precipitation at low temperature and microemulsion method show the reflections characteristic of CeO2 fluorite structure with cubic symmetry; the sample prepared by the Marcilly method is amorphous. The particle sizes are 3 and 8nm for the low temperature and microemulsion powders, respectively. X-ray photoelectron spectroscopy (XPS) analysis reveals the prevalent presence of Ce(III) in the sample obtained by means of the Marcilly method. The Marcilly and microemulsion samples were also treated at 473K for 5h and the influence of the thermal treatment was investigated. XPS and XRD data suggest that the powder obtained by the Marcilly procedure is converted to ceria by the thermal treatment.Methanol interacts molecularly and dissociatively with the CeO2 surface regardless of the preparation procedure but the mechanism of interaction is not always the same. Traces of oxidation products are noted only on the samples obtained by means of the microemulsion and Marcilly methods treated at 473K for 5h.
Keywords: Ceria; Methanol oxidation; TWC; SOFC; Nanopowders; XPS; DRIFT
Effects of metal content on activity and stability of Ni-Co bimetallic catalysts for CO2 reforming of CH4 by Jianguo Zhang; Hui Wang; Ajay K. Dalai (pp. 121-129).
This work focuses on the effects of Ni-Co content of the catalyst, attempting to avoid carbon formation on the catalyst by selecting proper metal ensemble size. Catalyst samples with different Ni and Co loadings were prepared, and the activity and stability for CO2 reforming of CH4 was tested at 750°C, 1atm and GHSV of 180,000mL/gcath. The results with 250h time-on-stream show that catalysts of lower Ni-Co content had high and stable activity with no deactivation and no detectable carbon formation and that those of higher Ni-Co content experienced apparent deactivation with significant carbon formation. Characterizations indicate that catalyst with lower Ni-Co content has larger surface area and better metal dispersion and therefore gives rise to smaller metal particles (<10nm) which is essential to the complete suppression of the carbon formation on catalyst. ▪Ni-Co bimetallic catalyst with a general formula of Ni-Co-Al-Mg-O prepared using coprecipitation has shown excellent stability and high activity for CO2 reforming of CH4 in our previous research. This paper focuses on the effects of Ni-Co content of the catalyst, attempting to avoid carbon formation on the catalyst. Catalyst samples with Ni and Co loadings ranging between 1.83 and 14.5wt.% and 2.76 and 12.9wt.%, respectively, were prepared and the activity and stability for CO2 reforming of CH4 was tested at 750°C and 1atm using a high GHSV of 180,000mL/gcath. The results show that catalysts with lower Ni-Co content (1.83–3.61wt.% for Ni and 2.76–4.53wt.% for Co) had higher and more stable activity with no deactivation and no detectable carbon formation and that those of higher Ni-Co content (5.28–14.5wt.% for Ni and 7.95–12.9wt.% for Co) experienced apparent deactivation with significant carbon formation in 250h time-on-stream tests. Catalyst characterizations using TEM, XRD, H2-TPR, TG/DTG-TPO, N2-physisorption, and CO-chemisorption indicate that catalyst with lower Ni-Co content has larger surface area, smaller metal particles and better metal dispersion and therefore gives rise to better catalytic performance. The absence of large metal particles (>10nm) is believed essential to the complete suppression of the carbon formation during reaction.
Keywords: Carbon dioxide; Reforming; Methane; Carbon formation; Synthesis gas; Metal dispersion
Direct synthesis of H2O2 from H2 and O2 over Pd–Pt/SiO2 bimetallic catalysts in a H2SO4/ethanol system by Qingsheng Liu; J. Chris Bauer; Raymond E. Schaak; Jack H. Lunsford (pp. 130-136).
The addition of only 5atom% Pt to a Pd/SiO2 catalyst resulted in a significant increase in the rate of H2O2 formation with only a small decrease in selectivity. The direct formation of the peroxide from H2 and O2 requires the presence of halides ions (Cl− or Br−), which inhibit both the selective and nonselective oxidation of H2. The Pt is believed to partially reverse the effect that the halides have on hydrogen activation.▪The effect of adding Pt to a Pd/SiO2 catalyst for the direct formation of H2O2 in ethanol that contains H2SO4 and halide ions (Cl− or Br−) has been investigated. The addition of only 5atom% Pt to a catalyst that contained 0.5wt.% Pd resulted in a 2.5-fold increase in the rate of peroxide formation with only a small decrease in selectivity. The addition of substantially more Pt caused a decrease in the selectivity; whereas, the peroxide formation rate depended on the amount of Pt, as well as the type and amount of the halide. The Pt had no significant effect on the particle size distribution of the supported bimetallic catalysts. The positive role of Pt on the rate of H2O2 formation can be understood in terms of an electronic modification through which Pt partially reverses the negative influence that the halides have on hydrogen activation.
Keywords: Hydrogen peroxide; Palladium/silica; Pd–Pt catalyst; Platinum; Promotional effect; Halides
Studies on phase formation temperature and photocatalytic properties of nano-sized solid solution of nickel molybdate and chromium–phosphate (Ni xCr1− xMo xP1− xO4) by Tanmay K. Ghorai; Debasis Dhak; Sudipta Dalai; Panchanan Pramanik (pp. 137-144).
The nano-sized Ni xCr1− xMo xP1− xO4 was synthesized by CSD method and photocatalytic activity was investigated. The average particle size of Ni xCr1− xMo xP1− xO4 ( x=0.1) was found to be 55±10nm and it has effective surface area is ∼72.85m2/g. It is showed the highest photocatalytic activity compared other mixed oxides due to small particle size and high surface area.▪The photocatalytic activity of various proportions of nickel–chromium–molybdenum–phosphorous (Ni xCr1− xMo xP1− xO4) oxides in the oxidation of thymol blue at pH 8.001 under both UV and visible light has been examined. The nano-size different compositions of Ni xCr1− xMo xP1− xO4 (where x=0.1, 0.2, 0.3 and 0.4) photocatalyst were prepared by chemical solution decomposition (CSD) method and characterized with X-ray diffraction (XRD), UV–vis spectroscopy, Transmission Electron microscopy (TEM), specific surface area (Brunauer–Emmett–Teller (BET)), X-ray photoelectron spectroscopy (XPS) and ICP analysis. The variations of phase separation temperature with respect to the amount of different constituents have been studied. The average particle size of Ni xCr1− xMo xP1− xO4 ( x=0.1) was found to be 55±10nm measured from Transmission Electron microscopy (TEM) and specific surface area (BET) is found to be ∼72.85m2/g.
Keywords: Solid solution; Nickel molybdate; Phosphate; Nano-size; Photocatalysis
Efficient oxidation of cyclohexene over tetrakis(diperoxomolybdo) phosphate immobilized on poly(phthalazinone ether sulfone ketone) with hydrogen peroxide by Zhihuan Weng; Jinyan Wang; Shouhai Zhang; Chun Yan; Xigao Jian (pp. 145-150).
Heteropoly anion [PMo4O24]3− (PMo) was immobilized on the quaternary-ammonium poly(phthalazinone ether sulfone ketone) (QAPPESK) support by taking advantage of the overall negative charge of anion. The supported catalyst QAPPESK–PMo was fully characterized by FT-IR and XRD. The results of analyses indicated that the PMos were finely dispersed on the polymer support via chemical interactions. This supported catalyst was employed to catalyze oxidation of olefins with hydrogen peroxide, and satisfying results were obtained under mild heterogeneous conditions. The effects of various reaction factors, such as solvent, the amount of H2O2 and catalyst used, were studied. Furthermore, the leaching and recycling tests revealed that the supported catalyst was highly efficient and robust.In this work, the heteropoly anion [PMo4O24]3− (b) with crystal structure was immobilized on the amorphous quaternary-ammonium poly(phthalazinone ether sulfone ketone) (a), and the XRD pattern of the supported catalyst (c) revealed that the anions immobilized on the polymer were not in a crystal state but in an amorphous state, and [PMo4O24]3− species were highly dispersed as fine particles on the polymer support.▪
Keywords: Heteropoly anion; Poly(phthalazinone ether sulfone ketone); Polymer-supported; Cyclohexene; Hydrogen peroxide
NO reduction with CO on alumina-modified silica-supported palladium and molybdenum-palladium catalysts by Julia María Díaz Cónsul; Ignacio Costilla; Carlos Eugenio Gigola; Ione Maluf Baibich (pp. 151-158).
In this work, Pd and Mo-Pd catalysts supported on Al2O3 modified SiO2 and Si-MCM-41 materials were prepared, characterized by H2 chemisorption and FTIR spectroscopy, of adsorbed CO and NO, and tested for the reduction of NO with CO. This result suggests that there is reaction of the NCO species, formed on the Pd surface, with OH groups of the support materials to produce isocyanic acid (HNCO), which is hydrolyzed to NH3.▪In this work, Pd and Mo-Pd catalysts supported on Al2O3 modified SiO2 and Si-MCM-41 materials were prepared, characterized by H2 chemisorption and FTIR spectroscopy of adsorbed CO and NO and tested for the reduction of NO with CO. The characterization results indicated that in the bimetallic catalysts, Mo that is loaded first, migrates over the Pd atoms and reduced the fraction of exposed metal atoms. The reduction of NO with CO at 523K showed that the specific activity for NO conversion increased as a result of the Pd-Mo interaction. In the 523–573K temperature range NH3 was produced in addition to CO2, N2 and N2O. This result suggests the reaction of NCO species formed on the Pd surface with OH groups of the support materials to produce isocyanic acid (HNCO) that is hydrolyzed to NH3. The catalysts exhibited a decreasing selectivity to N2O and a parallel increase in the production of N2 and NH3 as the conversion increases. The effect of Mo on the reaction selectivity was clear for Pd/Al2O3/SiO2; at similar NO conversion level the selectivity to N2O and N2 decreased with increasing NH3 formation. FTIR spectra of adsorbed species under reaction conditions demonstrated the absence of isocyanate species and the presence of NH4+ ions in accordance with the high Brønsted acidity of the support materials.
Keywords: NO; x; MCM-41; Pd catalyst; Mo-Pd catalyst; NO reduction with CO
Selective hydrogenation of cinnamaldehyde to cinnamyl alcohol over mesoporous carbon supported Fe and Zn promoted Pt catalyst by Nagendranath Mahata; Filomena Gonçalves; Manuel Fernando R. Pereira; José Luís Figueiredo (pp. 159-168).
The effect of Fe and Zn promotion on the performance of Pt-based catalysts towards the selective hydrogenation of cinnamaldehyde to the corresponding semi-hydrogenated alcohol was studied using a synthetic carbon xerogel as catalyst support. The promoted and unpromoted catalysts were fully characterised in order to correlate the corresponding properties with catalytic behaviour. ▪The effect of Fe and Zn promotion on the performance of Pt-based catalysts towards the selective hydrogenation of cinnamaldehyde to the corresponding semi-hydrogenated alcohol was studied using a synthetic carbon xerogel as catalyst support. The promoted and unpromoted catalysts were fully characterised in order to correlate the corresponding properties with catalytic behaviour.The addition of Zn or Fe to the Pt catalyst was found to improve the activity as well as the selectivity to cinnamyl alcohol. The simultaneous use of both promoters enabled to achieve a remarkably high selectivity along with high conversion; promoting effects of Fe and Zn towards selectivity seem to be additive.The important promoting effects observed were explained by the creation of new sites for the activation of the carbonyl group in the cinnamaldehyde molecule and by the development of electronic and stereo-hindrances.The carbon surface chemistry was also found to have a large influence on the catalytic properties.
Keywords: Selective hydrogenation; Cinnamaldehyde; Platinum catalyst; Fe and Zn promotion; Carbon xerogel; Cinnamyl alcohol
The effect of impregnation sequence on the hydrogenation activity and selectivity of supported Pt/Ni bimetallic catalysts by Yuying Shu; Luis E. Murillo; Jeffrey P. Bosco; Wei Huang; Anatoly I. Frenkel; Jingguang G. Chen (pp. 169-179).
The self-hydrogenation activity of cyclohexene and the hydrogenation selectivity of acetylene in ethylene were used as probe reactions to compare the effect of the impregnation sequence in bimetallic Pt/Ni catalysts supported on γ-alumina. Our results indicate that, at low Ni loadings, with a Pt/Ni atomic ratio of 3/1, the impregnation sequence has a significant effect on the formation of PtNi bimetallic bonds, which in turn lead to different catalytic performance.▪The effect of impregnation sequence on the formation of Pt/Ni bimetallic nanoparticles supported on γ-Al2O3 was investigated for catalysts with Pt/Ni atomic ratios of 3/1 and 1/1. These bimetallic catalysts were prepared with a fixed Pt loading (5wt.%) by incipient impregnation of one metal precursor and calcination, followed by the impregnation of the second metal precursor and a second calcinations step. The disproportionation activity of cyclohexene and the hydrogenation selectivity of acetylene in ethylene were used as probe reactions to compare the effect of the impregnation sequence. The bimetallic Pt/Ni catalysts showed significantly higher activity toward the disproportionation of cyclohexene than either Pt/γ-Al2O3 or Ni/γ-Al2O3. For catalysts with the Pt/Ni ratio of 3/1, the Pt-first catalyst, 1/3Ni-1Pt/γ-Al2O3, showed higher activity than the Ni-first catalyst, 1Pt-1/3Ni/γ-Al2O3. The effect of impregnation sequence was not as significant for catalysts with the Pt/Ni ratio of 1/1. In addition, kinetic analysis of the selective hydrogenation of acetylene in ethylene revealed an increase in the acetylene hydrogenation selectivity for 1/3Ni-1Pt/γ-Al2O3 as compared to both 1Pt-1/3Ni/γ-Al2O3 and monometallic 1Pt/γ-Al2O3. Extended X-ray absorption fine structure (EXAFS) measurements of the Pt LIII edge indicated that PtNi bimetallic bonds were formed in 1/3Ni-1Pt/γ-Al2O3 but not in 1Pt-1/3Ni/γ-Al2O3. The PtNi bonds were formed for the 1/1 ratio catalysts with both impregnation sequences. Overall, our results indicate that, at low Ni loadings, the impregnation sequence has a significant effect on the formation of PtNi bimetallic bonds, which in turn lead to different catalytic behavior for both the disproportionation of cyclohexene and the selective hydrogenation of acetylene in ethylene.
Keywords: Impregnation sequence; Pt/Ni bimetallic catalysts; Hydrogenation; Disproportionation; Cyclohexene; Acetylene; Ethylene
Understanding the effect of halide poisoning in CO oxidation over Au/TiO2 by S.M. Oxford; J.D. Henao; J.H. Yang; M.C. Kung; H.H. Kung (pp. 180-186).
Halide suppresses CO adsorption and CO oxidation activity on Au/TiO2 catalysts differently; the data were consistent with the perimeter of Au atoms at/near the particle-support interface (perimeter) being active sites, whereas all surface Au can adsorb CO.▪The effect of halide poisoning of Au/TiO2 catalysts in low temperature CO oxidation was investigated using bromide as the poison and a combination of X-ray absorption spectroscopy (XANES and EXAFS), quantitative CO adsorption, and catalytic measurements. It was found that halide prevented full reduction of cationic Au by displacing oxyhydroxy ligands and remaining bound to Au during low temperature reduction, causing a reduction in catalytic activity. On reduced Au samples, bromide (likely as NaBr molecule) was preferentially adsorbed on Au and not on TiO2, and suppressed both the adsorption of CO and the catalytic activity. At low Br contents, each adsorbed Br suppressed adsorption of three CO, suggesting that Br was adsorbed on three-fold sites but the effect decreased with increasing Br content possibly due to crowding of adsorbed Br. When 5–10% of the Au was bound to Br, the catalytic activity was completely blocked, although ∼35% of the original CO adsorption capacity remained. The data suggest that not all CO adsorption sites are catalytic active sites, and are consistent with the perimeter Au atoms at/near the particle-support interface (perimeter) being active sites.
Keywords: Gold; Nanoparticle; Halide; Poisoning; Perimeter sites; CO oxidation
Application of multi-walled carbon nanotubes as efficient support to NiMo hydrotreating catalyst by I. Eswaramoorthi; V. Sundaramurthy; Nikhil Das; A.K. Dalai; J. Adjaye (pp. 187-195).
The multi-walled carbon nanotubes (MWCNTs) were prepared by CVD method and used as support for NiMo hydrotreating catalysts. The hydrotreating activity of NiMo/MWCNTs catalyst with light gas oil derived from Athabasca bitumen at industrial conditions is significantly higher than that of conventional NiMo/γ-Al2O3 catalyst on catalyst mass basis.▪The feasibility of multi-walled carbon nanotubes (MWCNTs) as support to NiMo catalysts for hydrotreating of gas oil derived from Athabasca bitumen was tested in a trickle bed reactor at industrial conditions. High quality MWCNTs were prepared by CVD method using ferrocene as catalyst and toluene as carbon source. The produced MWCNTs were characterized by XRD, TEM, TGA and Raman spectroscopy in order to reveal the morphological and structural characteristics. Using functionalized MWCNTs as support, NiMo catalysts were prepared with varying Ni and Mo content by pore filling impregnation method. The calcined NiMo/MWCNTs catalysts were characterized by ICP-MS, N2 adsorption, XRD and TPR and the sulfide form of the catalysts was examined by DRIFT spectroscopy of adsorbed CO. The XRD patterns confirm the enhanced dispersion of MoO3 particles when increasing the Ni content from 0 to 4.5wt.% over 12wt.% Mo/MWCNTs. The TPR profiles indicate the two step reduction characteristics of Mo6+ to Mo in lower oxidation state such as Mo4+ and Mo0. The promoted and unpromoted MoS2 sites were clearly differentiated with the help of DRIFT of adsorbed CO over sulfided catalysts. The number of Ni promoted MoS2 (NiMoS phase) sites is increased significantly with increasing Ni addition up to 3wt.% over 12wt.% Mo/MWCNTs. The HDN and HDS activities of sulfided NiMo/MWCNTs using bitumen derived light gas oil were carried out at different temperatures under industrial condition. The HDN and HDS activities of the catalysts increased with increasing Ni content up to 3wt.% and Mo content up to 12wt.%. Based on weight of the catalyst, the HDN and HDS activities of 3wt% Ni–12wt.% Mo/MWCNTs are significantly higher than those over conventional Al2O3-based catalyst under the experimental conditions studied. The introduction of 2.5wt.% P to MWCNTs-based catalyst found to show a fall in hydrotreating activity.
Keywords: Multi-walled carbon nanotubes; NiMo catalyst; DRIFT of adsorbed CO; Hydrotreating; Light gas oil; NiMoS phase
Maximising carbon nanofiber and hydrogen production in the catalytic decomposition of ethylene over an unsupported Ni-Cu alloy by M. Castro Díaz; James M. Blackman; Colin E. Snape (pp. 196-208).
A Ni-Cu (4:1wt/wt) metal alloy catalyst has been studied for the catalytic decomposition of ethylene to produce hydrogen and carbon nanofibers. Both high ethylene conversions (>80%) and high hydrogen selectivities (75%) were obtained at 873 and 923K, and the Ni-Cu (4:1wt/wt) catalyst behaved similarly to a Ni-Pd (4:1wt/wt) catalyst. The carbon nanofibers obtained have diameters of around 250nm with no obvious differences between the Ni-Cu and Ni-Pd alloys.▪A Ni-Cu (4:1wt/wt) metal alloy catalyst has been studied for the catalytic decomposition of ethylene to produce hydrogen and carbon nanofibers. To maximise ethylene conversion in a horizontal tube reactor with high residence times, hydrogen yields and selectivities, the temperature, sample mass and ethylene flow rate were varied. Both high ethylene conversions (>80%) and high hydrogen selectivities (75%) were obtained at 873 and 923K. The highest coke yield obtained after just 3h was around 480gC/gNi+Cu at 873K (86% ethylene conversion) and was significantly higher than the value of 250gC/gNi+Cu which was previously reported as the maximum coke yield for the decomposition of ethylene over Ni-Cu catalysts at this temperature. At 923K, the optimum conditions were achieved with 50mg of Ni-Cu, which gave ethylene conversions of 74%, a hydrogen selectivity of 71%, hydrogen yields in excess of4000molH2/molNi+Cu and even higher coke yields of 1112gC/gNi+Cu after 15h with the catalyst still possessing high catalytic activity. The Ni-Cu (4:1wt/wt) catalyst behaved similarly to a Ni-Pd (4:1wt/wt) catalyst, which suggests that unsupported Ni-Cu alloys can replace the more expensive Ni-Pd alloys for the catalytic decomposition of hydrocarbons. In addition, there were no obvious structural differences between the carbon nanofibers obtained with the Ni-Cu and Ni-Pd alloys, which were twisted, branched and straight nanofibers composed of crystalline and amorphous carbon with diameters ranging from 30 to 300nm.
Keywords: Ethylene; Catalytic decomposition; Hydrogen; Nickel; Copper; Carbon nanofibers
Simulation of hydrotreating of light cycle oil with a system dynamics model by Zhengliang Liu; Ying Zheng; Weizhi Wang; Qikai Zhang; Lufei Jia (pp. 209-220).
The system dynamics methodology is introduced to dynamically simulate a commercial hydratreating process in a hydrotreator. The efficiencies of the hydrodesulphurization, hydrodenitrogenation, and hydrodearomatization, and the consumption rate of H2 gas during the hydrotreating process are simulated. The influence of the operating conditions such as liquid hourly space velocity and inlet feed temperature on these efficiencies and H2 consumption is also investigated numerically.▪To serve as a diesel fraction, light cycle oil (LCO) is commonly hydrotreated by a complicated and widely used industrial process under high temperature and high pressure. In this study, the system dynamics (SD) methodology is, for the first time, introduced to dynamically simulate this commercial hydratreating process along the axial positions of the hydrotreator. The proposed SD model is fully presented and validated by both direct and indirect structure validation tests. The efficiencies of the hydrodesulphurization (HDS), hydrodenitrogenation (HDN), and hydrodearomatization (HDA), and the consumption rate of H2 gas during the hydrotreating process are also simulated. The influence of the operating conditions such as the liquid hourly space velocity (LHSV) and the inlet feed temperature on these efficiencies and H2 consumption is investigated numerically.
Keywords: Abbreviations; BT; benzothiophene or easy sulfur; BNT; benzonaphthothiophene; CBZ; carbazole; DBT; dibenzothiophene; Di; di-aromatics; 4,6-DMDBT; 4,6-dimethyldibenzothiophene; HDA; hydrodearomatization; HDN; hydrodenitrogenation; HDS; hydrodesulphurization; IND; indole; LHSV; liquid hourly space velocity; 4-MDBT; 4-methyldibenzothiophene; 6-MDBT; 6-methyldibenzothiophene; Mono; mono-aromatics; QL; quinoline; Tetra; tetra-aromatics; Tri; tri-aromaticsHydrotreating; Light cycle oil (LCO); Simulation; System dynamics