NiMoS

Aromatic hydrogenation is accounted for using earlier developed rate equations [23]. The lower hydrogenation activity of NiMo compared to Pt is accounted for by increasing the activation energy by 23 kJ mol". The inhibition by hetero atom containing components on the... 

Weight percent profiles through first-stage (left) and second stage reactor of a) alkanes (full fines) and cycloalkanes (dashed fines) and b) aromatic components. Thick lines correspond to C23 finctions, thin lines to 23 fractions. Operating conditions p, 17.5 MPa LHSV 1.67 niL (nv hf molar H2/HC 18 Tmiei 661 K (reactor 1) 622 K (reactor 2). Catalyst NiMo on amorphous silica-alumina. 

Reaction Kinetics of the Hydrodenitrogenation of Decahydroquinoline over NiMo(P)/Al203 Catalysts... 

In the present study, the HDN of decahydroq unohne (DHQ) was studied over NiMo(P)/Al20.T catalysts in the presence and absence of H2S. The reaction took place at 593 K and 3.0 MPa, thus allowing us to observe the most important reaction intermediate, propylcyclohexylamine, and to calculate the kinetic constants from the experimental results. Rate and adsorption constants for the different reaction steps were determined by separate and by combined HDN studies of DHQ and cyclohexene. 

Ratios of trans-/cis-isomers at different space times over a NiMo/AlaO.i catalyst ... 

The reaction path DHQ THQl- OPA HC must be taken into account to explain the promotional effect of phosphorus in the absence of H2S. A strong promotional effect of phosphorus has been observed for the HDN of OPA over NiMo/AhOa catalysts, which could be explained by the larger adsorption constant of OPA on the P-containing catalyst. The HDN activity of OPA was even higher in the absence of H2S (16). 

A plot of In(l-x.A) hi(l-XB) should restUt in a straight line if the assumption is true. Figure 6 shows the resvilt of simultaneous reactions of DHQ and CHE. The curvature of the In(l-XDHq) In(l-xcHE) plot confirms that the adsorption sites for CHE and DHQ over the NiMo(P)/Al203 catalysts are not the same. 

The present results show that the separate steps in an HDN reaction network can not be Imnped together into one kinetic equation. The intermediate reactions may take place on different catal ic sites which differ in their ability to bind reactants, intermediates, and products. Phosphorus was foimd to modify the rate constants as well as the adsorption constants of the HDN reaction steps, indicating that it changes both the number and nature of the active sites of NiMo/AlaOa catalysts. 

Another recent patent (22) and related patent application (31) cover incorporation and use of many active metals into Si-TUD-1. Some active materials were incorporated simultaneously (e.g., NiW, NiMo, and Ga/Zn/Sn). The various catalysts have been used for many organic reactions [TUD-1 variants are shown in brackets] Alkylation of naphthalene with 1-hexadecene [Al-Si] Friedel-Crafts benzylation of benzene [Fe-Si, Ga-Si, Sn-Si and Ti-Si, see apphcation 2 above] oligomerization of 1-decene [Al-Si] selective oxidation of ethylbenzene to acetophenone [Cr-Si, Mo-Si] and selective oxidation of cyclohexanol to cyclohexanone [Mo-Si], A dehydrogenation process (32) has been described using an immobilized pincer catalyst on a TUD-1 substrate. Previously these catalysts were homogeneous, which often caused problems in separation and recycle. Several other reactions were described, including acylation, hydrogenation, and ammoxidation. 

In places where the orientation of the boundary changed, small precipitates were observed. Their EELS spectrum (Figure 5.45) showed that they had a composition corresponding to the NiMo-8 phase. 

HYDROPROCESSING OF 33% BLEND OF SHORT-CONTACT TIME SRC (Pressure 13790 kPa NiMo Catalyst)... 

NiW catalysts are the most active for hydrogenation and are best suited for aromatic saturation and hydrocracking. Accordingly, the poisoning effect of H2S and NH3 is significant in these catalysts. However, their HDS and HDN performance is less attractive than that obtained from NiMo and CoMo catalysts. 

NiMo and NiW formulations have succeeded in desulfurizing the sterically hindered compounds, by fully hydrogenating at least one of the lateral rings, facilitating their elimination. From this point of view, the need for a high hydrogenation activity when producing ultra-low sulfur fuel is explained. Consequently, the preferential application of a Ni-Mo(W) for the manufacture of ULS fuels can be easily understood, as well. 

Certain catalyst manufacturers claims to have optimized the preparation (CoMo catalysts), the formulation or the promotion (aromatic saturation) of their catalysts to achieve an appropriate balance of the hydrogenation function to desulfurize the sterically hindered compounds and yield the 15 ppm S fuel. However, the actual trend is to use NiMo catalyst for the treatment of the more refractory compounds, below 200 ppm S [22],... 

Naphtha hydrotreatment takes place at temperatures from 290°C to 370°C, pressures from 350 to 450psig and space velocity between 2 and 6h 1. Preferred catalysts are usually CoMo, but if coker naphthas and in some instances FCC or HCK naphthas are incorporated to the feed, then NiMo can represent a better option. 

Diesel HDT is carried out at temperatures between 310°C and 400°C, pressures from about 500 to 700psig, and 1—4h 1 of space velocity. Preferred catalyst may be CoMo or NiMo in a single bed or combined in graded beds, depending on the quality of the feed and on the specifications required for the product. 

Resids HDT is carried out at temperatures between 360°C and 450°C, pressures from about 1500 to 3000psig, and 0.2 to lh-1 of space velocity. Graded catalyst beds combining CoMo and NiMo catalysts can be adapted to the quality of the feedstock and depending on whether atmospheric or vacuum residues are going to be treated. HDT of resids is seen as a feedstock pretreatment for preparing feedstock for either mixed with ordinary FCC feeds or for HCK (mixed with VGO or to a resid HCK). The advantages... 

Pore size optimization is one area where developmental efforts have been focused. Unimodal pore (NiMo) catalysts were found highly active for asphaltene conversion from resids but a large formation of coke-like sediments. Meanwhile, a macroporous catalyst showed lower activity but almost no sediments. The decrease of pore size increases the molecular weight of the asphaltenes in the hydrocracked product. An effective catalyst for VR is that for which average pores size and pore size distribution, and active phase distribution have been optimized. Therefore, the pore size distribution must be wide and contain predominantly meso-pores, but along with some micro- and macro-pores. However, the asphaltene conversion phase has to be localized in the larger pores to avoid sediment formation [134],... 

Lebreton, R. Brunet, S. Perot, G., et al., Deactivation and characterization of hydrotreating NiMo/AL203 catalyst coked by anthracene. Studies in Surface Science and Catalysis, 1999. 126 p. 195. 

Zhao, Y. Czyzniewska, J., and Prins, R., Mechanism of the direct hydrodenitrogenation of naphtylamine on sulfided NiMo/A1203. Catal. Lett, 2003. 88 p. 155. 

Olive, J.-L. Biyoko, S. Moulinas, C., and Geneste, P., Hydroprocessing of Indole and o-Ethylaniline over Sulfided CoMo, NiMo, and NiW Catalysts. Appl. Catal, 1985. 19 pp. 165-174. 

Peries, J.-P. Jeanlouis, P. E. Schmidt, M., and Vance, P. W., Combining NiMo and CoMo Catalysts for Diesel Hydrotreaters, in NPRA Annual Meeting. 1999, March 21-23. 

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