Papers by Keyword: Hydrodesulfurization

Abstract: With different content of thiophene in coking crude benzene, the Orthogonal design experiments of thiophene hydrodesulfurization on a Ti modified Co-Mo-P/γ-Al₂O₃ catalyst were carried out in a micro-reactor under the reaction conditions of 2.3~2.7MPa,275~335°C, 0.5h^-1LHSV and H₂/Oil 600~750. The kinetic parameters and the intrinsic kinetics were acquired by 4-order Runge-Kutta method and the modified Simplex method. The power-law type kinetic model was established and consistent with the experiment data and highly acceptable and reliable.

Abstract: Ni₂P/TiO₂-Al₂O₃ catalysts were prepared by impregnation of nickel phosphate precursors followed by reduction in hydrogen. The catalysts were characterized by X-ray diffraction (XRD), N₂-adsorption specific surface area measurements (BET), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetry differential thermal analysis (TG-DTA). The effects of reduction temperature on catalyst structure and HDS activity were studied using a lab-scale continuous flow fixed-bed reactor.. The results indicated that the catalyst prepared with reduction temperature of 973 K exhibited the best performance. At a reaction temperature of 606 K, a pressure of 3.0 MPa, a hydrogen/oil ratio of 500 (V/V), and a weight hourly space velocity (WHSV) of 2.0 h^-1, the conversion of DBT HDS was 96.0%.

Abstract: Nickel phosphide Ni₂P catalysts supported on TiO₂-Al₂O₃ support were prepared by co-impregnation. The catalysts were characterized by XRD, BET, and XPS. The effects of calcination temperature on catalyst structure and HDS activity were studied. The results indicated that the catalyst prepared with calcination temperature of 773 K exhibited the best performance. At a reaction temperature of 606 K, a pressure of 3.0 MPa, a hydrogen/oil ratio of 500 (V/V), and a weight hourly space velocity (WHSV) of 2.0 h^-1, the conversion of DBT HDS was 96.0%.

Abstract: nanonickel phosphide Ni₂P catalysts supported on TiO₂-Al₂O₃ support were prepared by impregnation. The catalysts were characterized by XRD, BET, and XPS. The effects of impregnation method,Ni₂P loading on catalyst structure and HDS activity were studied. The results indicated that co-impregnation method is beneficial to the formation of Ni₂P and can avoid the formation of Ni₁₂P₅. The catalyst prepared with co-impregnation method, Ni₂P loading of 30% exhibited the best performance. At a reaction temperature of 606 K, a pressure of 3.0 MPa, a hydrogen/oil ratio of 500 (V/V), and a weight hourly space velocity (WHSV) of 2.0 h^-1, the conversion of DBT HDS was 96.0%.

Abstract: The reactivity of olefins and S-compounds and their distributions in different catalyst-bed lengths were experimentally evaluated with a FCC gasoline in a high-pressure fixed-bed continuous flow pilot unit over the CoMoS/γ-Al₂O₃ catalyst. The evaluation results demonstrated that the increased steric hindrances around the double bond (C=C) and that to the thiophene molecules could suppress the hydrogenation of olefins and hydrodesulfurization (HDS) of S-compounds, respectively. Meanwhile, the reaction temperatures could influence the acidic property of the CoMoS active phase confirmed by FT-IR analysis, and thus induced the different reactions. It was found that the isomerization of terminal olefins to internal olefins was promoted by the Brønsted acid sites (-SH) at low temperatures, as well as the skeletal isomerization by the strong Lewis acid sites occurred to a minor extent at high temperatures. Besides, the distributions of olefins and S-compounds in different catalyst-bed lengths showed that the removal of S-compounds reached 80% of its maximum conversion at the first 40% of the reactor length, however, the saturation of olefins increased linearly as the reactor length increased. Therefore, a new catalyst-loading method was developed, i.e., the upper 40% of the reactor length filling with catalyst of high HDS activity and the bottom 60% with catalyst of low olefin saturation activity, respectively. The evaluation results showed that the graded catalyst loading process showed higher selectivity in HDS of FCC gasoline.

Abstract: New lumping kinetic models, considering the effects of the nitrogen content in product and the correction coefficient of LHSV, were proposed to describe the hydrodesulfurization of crude Longkou shale oil. The kinetic parameters were obtained using nonlinear regression of the experimental data which were conducted in a bench-scale trick-bed reactor with NiW/Al₂O₃ catalyst at various conditions. The results show that the 4-lump model is the optimal model. The values of apparent activation energies of lumps 1, 2, 3 and 4 are 51.14, 62.64, 130 and 166.42kJ/mol, respectively. The validation and application of the 4-lump model were also investigated.

Abstract: This work presents the synthesis and hydrodesulfurization performance of NiMo sulfide catalysts supported on γ-Al₂O₃ during the hydrodesulfurization (HDS) of dibenzothiophene (DBT). The catalysts were synthesized by the co-impregnation method using an atomic ratio of Ni=Ni/(Ni+Mo)=0.5. The materials were characterized by N₂ physisorption, XRD and HRTEM. This catalyst exhibited the larger pore size and high specific surface area, as well as better morphological properties. The catalytic activity was evaluated using a high-pressure batch reactor at 280 °C and 3.0 MPa. The catalytic activity during HDS-DBT indicated that the NiMoS/γ-Al₂O₃ catalyst was better than that NiMoS/γ-Al₂O₃ catalyst. the NiMoS/γ-Al₂O₃ catalyst exhibits higher DDS selectivity (3.0) than NiMo/γ-Al₂O₃ catalyst (2.55).

Abstract: Bulk Ni-Mo-W hydrodesulfurization catalysts with high catalytic activity were synthesized via direct precipitation and controlled pH precipitation method, respectively. Analysis results shows that the preparation method has great influence on the morphology and pore structure, and further influence the hydrodesulfurization activity. The catalyst synthesized by controlled pH precipitation method has much higher surface area and pore volume, 132.9 m2/g and 0.30 mL/g, due to its developed porous structure accumulated by small crystal particles. The activity evaluation indicates that the bulk Ni-Mo-W hydrodesulfurization catalysts has good ultra-deep desulfurization activity of removing complex organic sulfur compounds, such as DBT and Cn-DBT.

Abstract: Porous NiMo sulphide was successfully synthesized from ethanol supercritical fluid drying technique using (NH₄)₂MoS₄ and Ni(NO₃)₂ as the precursors. It was shown that the NiMo sulphide had extremely high porosity and the specific surface area was 322 m²•g^-1. The results of DBT hydrodesulfurization experimental showed that the porous NiMo sulfide prepared had high HDS activity, which was 2.78 times higher than that of a commercialized supported catalyst.

Abstract: A series of Al₂O₃-ZrO₂ (AZ-X) composite oxides with different ZrO₂ contents were prepared by a chemical precipitation method. Ni-P/AZ-X catalysts were prepared by temperature-programmed reduction. The supports and catalysts were extensively characterized by X-ray diffraction (XRD) and BET. The effects of support composition and P/Ni molar ratios on the catalytic performance of the catalysts were investigated by thiophene hydrodesulfurization (HDS) and pyridine hydrodenitrogenation (HDN). In comparison with Al₂O₃, Al₂O₃-ZrO₂ (20 wt% ZrO₂) composite oxide supported Ni-P catalyst exhibited higher activity and the activities of HDS and HDN increased by 7.5 % and 11.1 %, respectively. Studies of Ni-P/AZ-X catalysts with varying initial P/Ni molar ratios indicated that oxidic precursors with molar ratios of P/Ni = 2/1 yielded catalyst containing phase-pure Ni₂P which exhibited optimal activity.