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To study the effect of pore size distribution (PSD) of Ni-Mo/Al2O3 catalysts on the hydrodemetallization (HDM) activity, catalysts with different PSD were prepared using activated carbon and ammonium bicarbonate as pore-expanding agents and the HDM reaction was carried out in a high pressure trickle-bed reactor and Saudi Arabia vacuum residuum as the feedstock. The catalysts showed good activity of removing metal nickel (Ni) and vanadium (V) when they contain 10–20 nm pores, but the catalysts with both 10–20 and >100 nm pores have higher activity of removing metal V. The effect of PSD on the removal of different metal compounds were also studied by analyzing different metal compounds distribution in its hydrotreated products. Both Ni and V compounds of small molecular size in the methanol extract and middle molecular size in the dimethylformatmide (DMF) extracts can be easily removed on the catalysts. However, most of the large molecular V and Ni compounds in the toluene extracts were the most resistant to be removed in the vacuum residuum hydrodemetallization. Large molecular V compounds in the toluene extracts can be hydrodemetallized effectively on the catalysts with macropore size (>100 nm) distribution. While catalysts with mesopore size distribution (10–20 nm) shows a higher HDNi activity for the large molecular Ni compounds in the toluene extracts. Catalyst with both 10–20 and >100 nm pore size distribution would be more appropriate for the Saudi Arabia vacuum residuum HDV and HDNi.

The hydrodenitrogenation (HDN) performance of a Chinese coker gas oil (CGO) was tested in a micro-fixed bed reactor over a nickel–tungsten supported on citric-treated Y zeolite mixed with a titania–silica composite catalyst (NiW/CYCTS) within the temperature range of 360–420 °C, operating pressure range of 5.0–8.0 MPa, liquid hour space velocity (LHSV) range of 0.5–2 h − 1 , H 2 /CGO ratio range of 400–1200 (v/v), and H 2 S concentration range of 1–5 wt.%. The effects of these parameters on the relative conversions of total nitrogen (TN), basic nitrogen (BN), and non-basic nitrogen (NBN) compounds were determined. The conversion of TN compounds enhanced as the temperature and operating pressure increased and as LHSV decreased. BN compounds were easier to be removed than NBN compounds; they were also affected more significantly by the reaction conditions. With increasing H 2 /CGO ratio, the conversion of BN and NBN compounds initially increased and then decreased thereafter. This finding may be attributed to the addition of phenyl-sulfide (PHS) in the feedstock. The kinetic study of the HDN reaction showed that TN, BN, and NBN compounds accorded with the pseudo-first-order kinetic model. The calculation of the rate constants and activation energies indicated that the HDN of NBN compounds controlled the removal of TN compounds. Moreover, the hydrogenation of N-heterocyclic was the controlling step for the conversion of NBN compounds. The results above can guide the development of CGO hydrotreating catalyst. With the information from this paper, the development of CGO hydrotreating catalyst can adjust the properties of the catalyst by decided technology which will favor the removal of NBN containing compounds.

Composites of TiO2–SiO2 oxides (CTS) with various Ti/Si atomic ratios were prepared by the sol–gel method, and the CO2 supercritical fluid extraction method was used to remove solvent in the gel. The effects of the Ti/Si atomic ratio and calcination temperature on the specific surface area, pore structure, acidity, and coordination status of the Ti atoms were investigated by N2 desorption, pyridine adsorption, X-ray diffraction (XRD), and X-ray absorption fine structure (XAFS), respectively. Hydrotreating catalysts were prepared with cobalt (Co)–molybdenum (Mo) and nickel (Ni)–tungsten (W) as active metal components supported on CTS-1 and CTS-4, respectively. The hydrotreating activities of the catalysts were tested by processing residue fluid catalytic cracking (RFCC) diesel on a fixed-bed reactor. It was found that hydrodesulfurization (HDS), hydrodenitrogenation (HDN), and hydrodearomatization (HDA) were affected by the acidity of the support and/or catalyst, which was related to the Ti/Si atomic ratio...

Three catalysts NiW/Al 2 O 3 , NiW–P/Al 2 O 3 and NiW–CA/Al 2 O 3 with different morphologies but similar pore structures and acidity properties were prepared for studying the effect of morphology properties on the hydrodesulfurization (HDS) activity for individual sulfur compounds in fluid catalytic cracking (FCC) diesel. The morphology properties of the selected catalysts in oxidation and sulfidation states were characterized and the contents of individual sulfur compounds were determined by gas chromatography–pulse flame photometric detector (GC–PFPD). The results showed that NiW–P/Al 2 O 3 possessed the highest edge density of WS 2 phase and NiW–CA/Al 2 O 3 had the highest stacking degree of multilayered WS 2 phase. The HDS assessment showed that NiW–CA/Al 2 O 3 demonstrated positive effects on the HDS of refractory sulfur compounds like 4,6-dimethyldibenzothiophene (4,6-DMDBT) or dibenzothiophene (DBT) with alkyl substitutes containing 3 carbons (C 3 DBT) but slight negative effects on the HDS of simple sulfur compounds such as benzothiophene (BT) with alkyl substitutes containing 1 ~ 5 carbons (C 1 ~ C 5 BT) and DBT with alkyl substitutes containing 1 carbon (C 1 DBT); while NiW–P/Al 2 O 3 favored for the HDS of simple sulfur compounds. The present results indicated that the morphology of WS 2 phase has a great influence on the HDS selectivity for different structured sulfur compounds.

The effects of the Y zeolite crystallite size on the hydrocracking activity and middle distillate selectivity in hydrocracking of vacuum gas oil have been investigated using Ni–W catalysts with zeo...

This article presents a novel method for preparing hydrodenitrogenation (HDN) catalysts via combined phosphorous modification of alumina and ethylenediaminetetraacetic acid (EDTA)-assisted dispersion of active metals. The results showed that the catalyst prepared with this method possessed high dispersion of nickel and tungsten species, ascribed to EDTA addition. Simultaneously, high sulfidation degree of tungsten and nickel species was obtained due to the addition of phosphorous and EDTA. So the catalyst prepared by this method exhibited a greatly enhanced hydrodenitrogenation activity than the conventional method prepared.