Hailiang Yin

NiMo/Al2O3 catalyst containing nano-sized zeolite Y for deep hydrodesulfurization and hydrodenitrogenation of diesel

Abstract Two mixed-matrix NiMo/Al 2 O 3 catalysts containing nano- and micro-sized zeolite Y have been prepared to explore the size effect of zeolite Y particle on the hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) activities of fluid catalytic cracking (FCC) diesel. They were characterized by SEM, BET, XRD, H 2 -TPR, NH 3 -TPD and HRTEM. The results show that the catalyst containing nano-sized zeolite Y possesses larger average pore diameter, higher pore volume, weaker and lesser acid sites, more easily reducible metal phases, shorter MoS 2 slabs and more slab layers than the catalyst containing micro-sized zeolite Y. The catalysts were also evaluated with a high-pressure fixed-bed reactor using real FCC diesel as feed. The results display that the catalyst containing nano-sized zeolite Y bears higher HDS and HDN activities and exhibits higher relative rate constant for the removal of total sulfur or nitrogen than the one containing micro-sized zeolite.

Influences of different phosphorus contents on NiMoP/Al2O3 hydrotreating catalysts

Abstract NiMoP/Al2O3 hydrotreating catalysts with different phosphorus contents were prepared by impregnating NiMoP aqueous solution into γ-Al2O3. The hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) performances of the catalysts were evaluated using the model compounds dibenzothiophene and quinoline in toluene. The results show that the HDS and HDN performances of the catalysts can be improved by adding appropriate quantities of phosphorus in the catalysts, and its performance can be decreased markedly when the catalysts have high phosphorus content. The catalysts were investigated by means of XRD and high-resolution transmission electron microscopy (HRTEM) to get a better understanding of the nature of active phases. The results of XRD and HRTEM characterizations indicate that the stacked layers number of active component MoS2 nanoparticles increases with the increase of the phosphorus content. Because the interaction between active component and γ-Al2O3 carrier is weakened by adding phosphorus into the catalysts, the relative content of type-II “Ni-Mo-S” phase is increased.

Effect of phosphorus content on the active phase structure of NiMoP/Al2O3 catalyst

Abstract NiMoP/Al2O3 catalysts with different phosphorus contents were prepared by co-impregnation method and are characterized by temperature-programmed reduction (TPR), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) tests. The effect of phosphorus content on the active phase structure of these catalysts was investigated. The TPR results indicated that with the increase of the phosphorus content in the catalysts, the amount of tetrahedral Mo species was decreased, while that of octahedral Mo species was increased. The HRTEM results showed that the number of stacking layers of MoS2 nanoparticles increased with the phosphorus content, which was effective in enhancing the hydrogenation selectivity of the catalysts. The fraction of available Mo dispersion (fMo) and the number of active phases in the catalysts increased with increasing phosphorus content to P/MoO3 = 0.09; beyond that, a reverse trend was observed. High HDS and HDN activity were obtained over the catalyst with the phosphorus content of P/MoO3 = 0.09, which could be attributed to its high concentration of Mo atoms on the catalyst surface, high-efficient promotion rate (PR) and high promoter ratio (Ni/Mo). However, excessive phosphorus content may deteriorate the performance of NiMoP/Al2O3 catalysts due to the aggregation of active components.

Study on the structure of active phase in NiMoP impregnation solution using Laser Raman spectroscopy II.Effect of organic additives

Abstract Laser Raman spectroscopy (LRS) was used to characterize the NiMoP impregnant with different contents of glycol and citric acid as well as dried Al 2 O 3 impregnated with this NiMoP impregnant. The effect of glycol and citric acid on the structure of active phases in NiMoP impregnant and during the impregnation process was investigated. The results indicated that with glycol as the additive in the NiMoP(0.063) impregnant, the active phases like H x [PMo 11 O 39 ] (7− x )− or H x [PMo 9 O 31 ] (3− x )− ) and H x [PMo 12 O 40 ] (3− x )− are converted to H x [P 2 Mo 5 O 23 ] (6− x )− . With citric acid as the additive, H x [P 2 Mo 5 O 23 ] (6− x )− , (H x [PMo 11 O 39 ] (7− x )− or H x [PMo 9 O 31 ] (3− x )− ) and H x [PMo 12 O 40 ] (3− x )− are present together in the NiMoP(0.063) impregnant; however, citric acid leads a decrease of H x [P 2 Mo 5 O 23 ] (6− x )− content but an increase of H x [PMo 12 O 40 ] (3− x )− . Compared with glycol, during the impregnation of alumina with the NiMoP impregnant, citric acid is more effective in preventing the active phases from being decomposed in the cavities of alumina.

Study on the structure of active phase in NiMoP impregnation solution using Laser Raman spectroscopy 1. Effect of phosphorous content

Abstract Laser Raman spectroscopy (LRS) was used to characterize the NiMoP impregnation solution and dried samples of NiMoP impregnated on γ-Al2O3. The effect of phosphorous content on the structure of the active phases in NiMoP impregnation solution and that during the impregnation process was studied. The LRS results indicate the active phases in NiMoP impregnation solution with lower phosphorous content are composed of several heteropoly compounds such as NixH6–2x[P2Mo5O23], NixH7–2x[PMo11O39] or NixH3–2x[PMo9O31] and NixH3–2x[PMo12O40]. NixH6–2x[P2Mo5O23] is dominant when phosphorous content increases. In addition, these active phases in NiMoP impregnation solution with lower phosphorous content are converted to seven poly-molybdate when the impregnation solution is impregnated into the cavities of γ-Al2O3, while higher phosphorous content hinders this conversion.

The Preparation of Ni/ZnO Adsorbent via a Low-Temperature Solid-State Method for Ultra-deep Desulfurization

Abstract One novel synthetic approach has been proposed to prepare Ni/ZnO adsorbent via low-temperature solid-state reaction. Thermal analysis (thermogravimetry differential scanning calorimetry [TG-DSC]) revealed that the nickel–zinc oxalate precursor obtained is a single-phase composite oxalate. Transmission electron microscopy analysis (TEM) shows that the NiO/ZnO composite materials are composed of nanoparticles with good dispersivity, whereas the elements of Ni and Zn are well distributed. The activity evaluation indicates that the Ni/ZnO adsorbent has good ultra-deep desulfurization activity of removing organic sulfur compounds. The sulfur concentration in the treated gasoline is less than 1.0 μg/g, which meets the need of ultra-low-sulfur fuels for use in fuel cells.

Hydrogen spillover effect between Ni2P and MoS2 catalysts in hydrodesulfurization of dibenzothiophene

Abstract The hydrodesulfurization of dibenzothiophene over physically separated Ni 2 P//MoS 2 catalyst beds was investigated. The results indicated that the hydrogen spillover effect appears between the Ni 2 P/Al 2 O 3 and MoS 2 /Al 2 O 3 catalysts in the hydrodesulfurization reaction, which can significantly enhance the concentration of active sites and the hydrodesulfurization rate over the MoS 2 catalyst. The spillover factor on Ni 2 P//MoS 2 is slightly higher than that on NiS x //MoS 2 , due to the higher hydrogen dissociation activity of Ni 2 P; as a result, Ni 2 P is a superior promoter to NiS x for the MoS 2 catalyst.