O. V. Klimov

The superior activity of the CoMo hydrotreating catalysts, prepared using citric acid: what's the reason?

Abstract It was demonstrated, that the main positive role of citric acid during the hydrotreating catalysts preparation is consist in the formation of bimetallic complex Co 2 [Mo 4 (C 6 H 5 O 7 ) 2 O 11 ]•nH 2 O, that is a good precursor for selective formation of catalyst active phase, so called Co-Mo-S phase type II. The preparation method for this bimetallic complex using different precursor is described. The catalysts prepared by the complex deposition onto alumina support were studied during the different stages of the catalyst genesis. Applicability of these catalysts for ultra low sulfur diesel production was shown.

Influence of the heat treatment conditions on the activity of the CoMo/Al2O3 catalyst for deep hydrodesulfurization of diesel fractions

The effect of the heat treatment temperature on the sulfidation and activity of CoMo/Al2O3 catalysts designed for deep hydrodesulfurization of diesel fuel was studied. The catalysts were prepared using citric acid as a chelating ligand. The organic ligands present in the samples heat-treated at 110 and 220°C retard the decomposition of dimethyl disulfide and the formation of the sulfide phase but make the catalyst more active than the samples calcined at higher temperatures.

Synthesis properties and structure of binuclear anionic “Mo(V) hydroxide”, [Mo2O4(OH)4(H2O2]2−

Abstract The structure of “molybdenum(V) hydroxide” has been defined. The complex was obtained from MoO42−4 molybdate anion reduction with hydrazine-hydrate in aqueous solution. This compound is assigned the formula (N2H5)2[Mo2(μ-O)2(OH)4(H2O)2], dihydrazonium[di-μ-oxo-bis-(aquadihydroxooxomolybdate(V)]. The product similar in structure as that obtained on MoO2−4 reduction with NaBH4 and on (NH4)2MoOCl5 hydrolysis. Upon dissolving molybdenum(V) hydroxide in oxalic or tartaric acid solutions the diamagnetic complexes are obtained and characterized by means of IR, NMR and EXAFS spectroscopy.

Complexes forming from ammonium paramolybdate, orthophosphoric acid, cobalt or nickel nitrate, and carbamide in solution and their use in the preparation of diesel fuel hydrodesulfurization catalysts

It is demonstrated by 14N, 17O, 31P, and 95Mo NMR spectroscopy that the heteropolyanion [P2Mo5O23]6− forms in impregnating solutions containing orthophosphoric acid, ammonium paramolybdate, cobalt or nickel nitrate, and carbamide. The anion forms labile complexes with Co2+ or Ni2+ cations by coordinating to them through terminal oxygen atoms of the MoO6 octahedra and outer oxygen atoms of the PO4 groups. The catalysts prepared by supporting these complexes on Al2O3 are highly active in diesel fuel hydrodesulfurization. They compare well with the best foreign analogues and are superior to most of the Russian commercial hydrodesulfurization catalysts.

Bimetallic Co-Mo-complexes with optimal localization on the support surface: A way for highly active hydrodesulfurization catalysts preparation for different petroleum distillates

Abstract The preparation method of the catalyst for the deep hydrotreatment of vacuum gas oil and gasoline is described. The method is based on vacuum impregnation of the carrier with required average pore diameter with the solution of bimetallic CoMo complexes. It was shown that the use of Co-Mo complexes, containing chelating ligands and having different molecule size, allows to obtain catalysts with the uniform distribution of the surface species, containing supported metals only in the form of Co-Mo-S phase type II that is located inside of the pores exposed to all reacting heteroatomic molecules of the feedstock.

Synthesis of NiW/Al2O3 hydrotreating catalysts from ammonium paratungstate using chelating agents

Procedures are suggested for preparing NiW/Al2O3 catalysts using ammonium paratungstate as a tungsten source and citric acid and D(+)-sorbitol as chelating agents. The catalysts prepared using the suggested reagents are characterized by increased dispersity of the sulfide component compared to the NiW/Al2O3 catalyst prepared by the traditional procedure using ammonium metatungstate and nickel(II) nitrate. In transformations of dibenzothiophene, quinoline, and naphthalene, the NiW/Al2O3 catalysts prepared using ammonium paratungstate and citric acid or D(+)-sorbitol considerably surpass in the activity the NiW/Al2O3 catalyst prepared by the traditional procedure.

A new catalyst for the deep hydrotreatment of vacuum gas oil, a catalytic cracking feedstock

A new CoNiMo/Al2O3 deep vacuum gas oil hydrotreatment catalyst designed for the production of catalytic cracking feedstocks containing 200–500 ppm of sulfur is developed. The method for its preparation includes the following stages: the preparation of a support with specified textural, strength, and granulometric characteristics; the synthesis of bimetallic (Co-Mo and Ni-Mo) complex compounds in solution; and their deposition and drying. The new sample is compared to current domestic and imported industrial analogs according to their physicochemical (texture, morphology, active phase structure) and catalytic characteristics and analyzed. It is shown that the catalyst allows hydrotreatment at temperatures 5–20°C lower and target fraction yields 4–13% higher than all the reference samples. The high activity of the new catalyst is due to the formation of one-layer trimetallic Co(Ni)MoS phase particles at the stage of its sulfidation. The catalyst preparation technique is ready for industrial use (OOO Sintez, Barnaul, 1000 t/yr), and the principal technological regimes of the hydrotreatment of vacuum gas oil on the developed catalyst are determined.

The use of X-ray absorption spectroscopy for developing new-generation Co-Mo catalysts of hydrotreating of diesel fuel

The immediate problem facing the Russian petroleum refining industry is to turn to the production of gasoline complying with European standards [1]. Nowadays, only 12 of the 27 large Russian oil refinery plants have mastered the production of low-sulfur diesel fuel containing less than 0.05% sulfur [2]. Almost all diesel fuel that meets Euro 2, Euro 3, and Euro 4 standards is produced with the use of foreign catalysts since domestic catalysts do not have the required activity level. In this context, Russian industry should proceed as soon as possible to produce new-generation heterogeneous catalysts in which all surface compounds are active centers of hydrorefining reactions. According to the basic principles of the preparation of such catalysts expounded in [3], active center precursors—bimetallic Co‐Mo compounds—should be obtained when preparing an impregnating solution and the structure of these compounds should remain unaltered during the genesis of catalysts. The existence of such a structure in an oxide precursor of hydrorefining catalysts will ensure the formation of highly active disperse sulfide particles during the sulfiding step. To purposefully use this approach, the state and structure of catalyst active component precursors should be thoroughly monitored at all stages of their preparation. The most suitable for this purpose is X-ray absorption spectroscopy, which makes it possible to identify the structure of compounds synthesized in solution and on the support surface during catalyst preparation [4]. In this paper, we report the results of the EXAFS and XANES study of the structure of bimetallic oxide precursors of the active phases of hydrorefining Co‐Mo catalysts. A bimetallic compound and allied catalyst were synthesized from the ammonium salt of the tetranuclear anion [Mo 4 (e 6 c 5 O 7 ) 2 O 11 ] 4– . Solutions and cata

Influence of the conditions of hydrogenation treatment of black oil on the yield and properties of the products obtained

The conversion of black oil in hydrogen (hydroconversion) and nitrogen (pyrolysis) media was studied. The influence of the hydrogen pressure and temperature of the hydrotreating of black oil on the yield and properties of the resulting liquid hydrocarbons was examined. Hydrogen actively participates in the conversion of kerogen (major organic component of black oil), which leads to an increase in the conversion of the organic matter, to an increase in the yield of liquid hydrocarbon products, and to improvement of their quality, compared to pyrolysis. The highest conversion of organic carbon (91.7%) and the maximal yield of liquid hydrocarbons (30.7 wt %) were reached in a hydrogen medium at a pressure of 10.0 MPa and a temperature of 400°C.

Hydrocracking of vacuum gas oil in the presence of catalysts NiMo/Al2O3–amorphous aluminosilicates and NiW/Al2O3–amorphous aluminosilicates

Supported nickel–molybdenum and nickel–tungsten hydrocracking catalysts prepared using a support that consists of 70% Al2O3 and 30% amorphous aluminosilicate were characterized by nitrogen and mercury porosimetry, IR spectroscopy of adsorbed CO, and high-resolution electron microscopy. The catalytic tests in hydrocracking of vacuum gas oil containing 3.39% sulfur showed that the nature of the hydrogenating component (NiMo or NiW) only slightly influences the vacuum gas oil conversion and the diesel fraction yield, but noticeable influences the properties of the diesel fraction obtained. The catalyst NiMo/Al2O3–amorphous aluminosilicates, compared to NiW/Al2O3–amorphous aluminosilicates, ensures lower sulfur content in the diesel fraction obtained, whereas the catalyst NiW/Al2O3–amorphous aluminosilicates allows obtaining a diesel fraction with lower content of polyaromatic compounds.