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The effect of Si/Al ratio of zeolite Y on the performance of NiW catalysts for second stage hydrocracking was studied. The zeolites were characterized by IR spectroscopy of adsorbed pyridine, low-temperature N2 adsorption, and temperature-programmed desorption of ammonia. The observed decrease of Bronsted and Lewis acid sites concentration relates to the increase of Si/Al ratio in zeolites. According to HRTEM and XPS, sulfide component of catalysts differs in morphology, NiWS phase content and tungsten sulfidation degree. The catalysts were tested in hydrocracking of model (squalane) and real feedstock (unconverted oil (UCO) from two-stage industrial hydrocracker) at different temperatures. The increase of Si/Al ratio in zeolites was found to result in the decrease of catalytic activity and the increase of selectivity to middle distillates. However, similar selectivity of 52 and 53% at the 50% of UCO conversion was observed for catalysts containing zeolites with Si/Al ratio 24 and 37 respectively. This can be attributed mainly to the differences in the textural properties of the zeolites. The catalyst based on amorphous silica-alumina (without zeolites) was found to have a higher selectivity to middle distillates and lower activity as compared to zeolite-based catalysts.

The feasibility of the reactivation of CoMo/Al2O3 hydrotreating catalysts poisoned by Si compounds has been studied. CoMo/Al2O3 catalysts poisoned with 3, 4 and 5 wt.% of silicon were obtained during hydrotreating of diesel fraction contaminated with decamethylcyclopentasiloxane. Catalysts poisoned by different amount of silicon were regenerated by oxidative treatment and subsequently reactivated using citric acid solution. The catalysts were studied by nitrogen adsorption-desorption method, CHNS analysis, UV–vis, thermal analysis, SEM, HRTEM, XPS. It was shown that the hydrodesulfurization activity of regenerated catalysts decreased with increasing silicon content. According to UV–vis results, the increase in Si content on the spent catalyst leads to the formation of CoOx oxides after oxidative regeneration. Probably, cobalt oxides do not promote MoS2 slabs during sulfidation, convert to inactive Co species and decrease hydrodesulfurization activity. After reactivation procedure, there was the increase in active component particles dispersion, while catalytic activity in hydrodesulfurization of dibenzothiophene and hydrodenitrogenation of quinoline increased. It was established that hydrodesulfurization and hydrodenitrogenation activities of CoMo/Al2O3 catalyst with less than 3 wt.% of Si could be completely restored by reactivation.

The present work studies the influence of nitrogen compounds in hydrotreated fluid catalytic cracking (FCC) feedstock on the material balance of FCC process focused on petrochemistry. Vacuum gas oil was hydrotreated at the temperatures of 340–370 °C in typical FCC pretreatment conditions. The obtained hydrotreated products contained 370−750 ppm of nitrogen and 150−820 ppm of sulfur. Hydrotreated feedstock was exposed to the FCC process over a zeolite catalyst at the laboratory unit with a fixed bed catalyst at 527 °C and catalyst/oil ratio - 2−6. The FCC feedstock before and after hydrotreatment and FCC products were characterized by different methods to study the effect of nitrogen compounds on the FCC process.

NiW catalysts for second stage hydrocracking were prepared by impregnation of granulated supports with ultrastable zeolite Y content of 5−30 wt%; amorphous silica-alumina content of 45−20 wt%; and γ-Al2O3 content of 50 wt%. The catalysts were studied by low-temperature N2 adsorption, HRTEM, XPS and IR spectroscopy of adsorbed pyridine. Sulfide NiWS particles have been revealed to be similar in all the catalysts according to HRTEM and XPS. It has been shown that concentration of Bronsted acid sites increases with increasing of zeolite content in the catalysts. Hydrocracking tests were carried out at a pressure of 16.0 MPa, a LHSV of 1.4 h−1 and H2 to oil ratio of 750 (v/v). Two samples of unconverted oil with nitrogen content of 11 and 65 ppm obtained from the products of VGO hydrocracking under different severities were used as the feedstocks. The higher zeolite content the higher activity of the catalyst was achieved. However, the increase of zeolite content leaded to the decrease of selectivity to diesel. It has been found that increasing of nitrogen content in the feedstock was followed by a sharp decline in catalyst activity while the change in selectivity to diesel was insignificant. Optimal zeolite content in the support for studied conditions and feedstock with nitrogen content of 65 ppm was 20 wt%.

In this work, a series of the chromia/alumina catalysts with the same surface Cr concentration of 4.4 ± 0.2 at. Cr/nm2 and different K loadings (0–3.9 wt.%) has been investigated to evaluate the effect of K on the effective activation energy of isobutane dehydrogenation at 520−550 °C. The results of the study show that at K loadings up to 2.0 wt.%, K preferably interacts with alumina and modifies an average dispersion of Cr3+Ox species in the reduced catalysts, thus leading to a growth of conversion and selectivity, but the number of direct contacts of K with active sites is too low to affect the effective activation energy of dehydrogenation. When K loading is higher than 2.0 wt.%, the alumina capacity for K is reached and K interacts directly with Cr3+Ox species. This causes an enlargement of effective activation energy with K loading. One possible explanation relies on the formation of a new type of active sites in Cr3+-O(H)-K+ with modified energetics of the reaction pathway or even with other reaction pathway. Another explanation is that potassium ions, being in contact with active sites, induce strong chemisorption of water, which poisons active sites, especially at low temperatures of the reaction.

NiMo/B-Al2O3 catalysts for VGO hydrotreating differed in peptizing agent for supports preparation (nitric acid or ammonium solution) have been studied. The molar ratio of HNO3/Al2O3 = 0.03 and NH3aqua/Al2O3 = 0.09 and 0.15 were used. Supports and catalysts were studied by the nitrogen and mercury adsorption, IR-spectroscopy of adsorbed CO, XRD, 11B and 27Al NMR, UV–vis DRS, HRTEM, XPS. NiMo/B-Al2O3 catalyst peptized by ammonia at molar ratio of NH3/Al2O3 = 0.09 contains higher amount of NiMoS phase than catalysts peptized by nitric acid. Boron catalyst based support peptized by nitric acid is characterized by active component particles with lower slab length. Simultaneous presence of ammonia and boron results in increase of the slab length of active component, while stacking number decreases. According to the results of catalytic testing in HDS of DBT, boron-containing catalysts are more active. However, NiMo/B-Al2O3 catalyst obtained using ammonia with molar ratio of NH3/Al2O3 = 0.09 has higher activity in HDS of DBT in comparison with NiMo/B-Al2O3 catalyst obtained using nitric acid. Testing in VGO hydrotreating confirmed that utilization of ammonia as a peptizing agent for support preparation significantly improves the activity of boron catalyst in HDS and HDN reactions.

The review presents an analysis of the scientific and technical level and tendencies in the development of modern imported and Russian catalysts for the main hydroprocesses of oil refining—hydrocracking of vacuum gas oil and hydrotreatment of various distillates (catcracked gasoline, diesel fuel, vacuum gas oil). Forecasts were made on prospects for the industrial production and mass use of Russian catalysts for hydroprocesses.

A comparative study of the effect of citric acid (CA), nitrilotriacetic acid (NTA), and diethylene glycol (DEG) used for the preparation of impregnation solution on the properties and catalytic per...

In this work, the effect of surface properties of different alumina supports for CrOx/Al2O3-catalysts on Cr-speciation and dehydrogenation activity was studied. For this purpose, a series of CrOx/Al2O3-catalysts with a monolayer coverage of CrOx (ca. 4.4 at. Cr/nm2) was prepared with γ-, δ-, (δ + θ)-, η-, θ-Al2O3 as supports. Systematic investigation of fresh catalysts with a set of techniques (chemical analysis, N2 adsorption, XRD, Raman and ESR spectroscopy) showed that (i) chemical state distribution of Cr (Cr6+, Cr5+, Cr3+) was the same for all of the catalysts; (ii) CrOx-species were in X-ray amorphous state; (iii) surface chromate species were virtually of the same oligomerization degree. However, aggregation of Cr3+ ions both in calcined and reduced catalysts is support-dependent. ESR data and infrared spectroscopic results of adsorbed CO showed that increase of Lewis acid sites (LAS) surface density on bare aluminas promotes the growth of the relative amount of Cr3+ ions in a relatively large Cr2O3-like clusters in the fresh catalysts. Catalytic testing in a cycling dehydrogenation-regeneration mode leads to catalyst deactivation. Investigation of spent catalysts revealed that deactivation is accompanied with sintering of Cr3+Ox-species with partial migration of Cr3+ ions inside alumina. It was observed that increase of LAS surface density on aluminas promotes the growth of both the initial dehydrogenation activity and stability upon cycling. On the basis of experimental results, it was concluded that (i) Cr3+ ions on the surface of relatively large Cr2O3-like clusters are more active than isolated and poorly agglomerated Cr3+ ions; (ii) increase in LAS concentration on alumina induces growth of surface coverage by Cr2O3-like clusters with concomitant modification of intrinsic activity of active sites through their interaction with support.

Multi-walled carbon nanotubes (MWCNT) and alumina supported CоMо hydrotreating catalysts prepared with citric acid as a chelating agent (CoMoS/MWCNT-citr and CoMoS/Al2O3-citr respectively) were studied. MWCNT supported catalyst prepared without chelating agent (CoMoS/MWCNT) was also investigated. The addition of citric acid in MWCNT supported catalyst decreases the average slab length of MoS2 from 4.2 to 3.0 nm without increasing the stacking, while the differences in sulfidation degree and MoS2 promotion by cobalt are not observed. The activity of MWCNT-based catalyst in dibenzothiophene hydrodesulfurization (HDS) increases with the addition of citric acid due to improved dispersion of sulfide component. The activity in naphthalene hydrogenation does not change. The results of comparative study of MWCNT and Al2O3 supported catalysts prepared with citric acid show that the catalysts have rather similar morphology of sulfide phase: average slab length of about 3 nm and average stacking number of 1.6-1.7. At the same time, in MWCNT-based catalyst, active metals are sulfided more easily and CoMoS phase is formed at higher extent due to weaker metal-support interaction. CoMoS/MWCNT and CoMoS/Al2O3-citr catalysts are both highly active in HDS and demonstrate similar conversion of dibenzothiophene. The highest HDS activity of CoMo/MWCNT-citr catalyst is attributed to the beneficial effect that is provided by the combined use of carbon support (higher sulfidation degree and higher CoMoS phase content) and citric acid (improved dispersion of sulfide component).

The influence of alumina precursors on NiMo/γ-Al2O3 catalysts for silicon removal from gas oil have been studied. Alumina precursors were prepared by hydrothermal treatment of gibbsite, precipitation of aluminum nitrate by ammonia and precipitation of aluminum nitrate in autoclave. Alumina precursors, supports and catalysts were studied by XRD, nitrogen adsorption-desorption, IR spectroscopy, UV–vis, XPS, SEM, HRTEM. Series of NiMo/γ-Al2O3 catalysts differed in preparation method of alumina precursors was tested in hydrotreating of diesel fraction contaminated with decamethylcyclopentasiloxane as a model silicon compound. It was shown that prepared alumina precursors were boehmites and dawsonite, which had different particle size. The supports prepared from these alumina precursors were γ-Al2O3 with different particles size. It was shown that there was a dependence of the surface area of the support on the size of primary particles measured by XRD. The higher surface area results in the higher content of OH groups and silicon sorption capacity. Morphology of the sulfide active component also depends on the size of primary particles. The higher length of the particles, the higher slab length of NiMoS phase. The catalyst with the lowest particle size of alumina and highest length of active component had the highest HDS activity.

The influence of alumina precursors on catalytic activity CoMoP/Al2O3 hydrotreating catalysts has been studied. Alumina precursors were prepared by eco-friendly technology including hydrothermal treatment at different stabilization time of a flash calcined gibbsite. One sample was synthesized with the addition of boric acid. A reference sample of pseudoboehmite was obtained by precipitation from aluminum nitrate with aqueous ammonia. Alumina precursors, supports and catalysts were studied by XRD, nitrogen adsorption/desorption, XPS, HRTEM. CoMoP/Al2O3 catalysts were tested in hydrotreating of model feed and fuel mixture. It is shown that the samples obtained from the product of flash calcination of gibbsite, besides pseudoboehmite, also include the amorphous phase, while the reference sample, synthesized by precipitation, is a pure pseudoboehmite. The introduction of boron prevents the crystallization of pseudoboehmite. Textural properties of the catalysts depend of initial support: alumina samples prepared by hydrothermal treatment have a bimodal pore distribution with peaks at 60–70 A and 150–200 A, the support synthesized through reprecipitation has a unimodal distribution with a maximum at 80 A. The initial alumina used as a catalyst support has a significant impact on the share of CoMoS phase of type II. The highest activities in the hydrotreating of model feed (dibenzothiophene, quinoline and naphthalene in undecane) and fuel mixture shown catalyst prepared using hydrothermal treatment of flash calcined gibbsite without addition boric acid and with short stabilization time.

Zeolites of the MTT framework type (Si/Al = 30) have been synthesized using dimethylformamide as a template and by a template-free method (Si/Al = 24). The morphology, textural, and acidic properties of the synthesized zeolites have been studied by scanning electron microscopy, high-resolution transmission electron microscopy, N2 adsorption, IR spectroscopy of adsorbed pyridine, and temperature-programmed desorption of ammonia and compared with the properties of a commercial ZSM-23 zeolite (Si/Al = 24). Zeolite powders have been used to prepare ZSM-23+Al2O3 supports and then Pt-modified bifunctional catalysts, the properties of which have been tested in n-decane hydroconversion. It has been shown that the isomerization activity of the Pt/ZSM-23/Al2O3 catalysts is largely determined by the texture and morphology of the original zeolites.

Hydrotreating is one of the largest processes used in a refinery to improve the quality of oil products. The great demand of the present is to develop more active catalysts which could improve the energy efficiency of the process when it is necessary for heavier feedstock to be processed. Unsupported catalysts could solve this problem, because they contain the greatest amount of sulfide active sites, which significantly increase catalysts’ activity. Unfortunately, most of the information on the preparation and properties of unsupported catalysts is devoted to powder systems, while industrial plants require granular catalysts. Therefore, the present work describes a method for the preparation of granular Ni—Mo—W unsupported hydrotreating catalysts and studies the influence of the Ni/Mo/W atomic ratio on their properties. Catalysts have been prepared by plasticizing Ni—Mo—W precursor with aluminum hydroxide followed by granulation and drying stages. Ni—Mo—W precursor and granular catalysts were studied by X-ray diffraction (XRD), nitrogen adsorption–desorption method, high-resolution transmission electron microscopy (HRTEM), and thermal analysis. Granular catalysts were sulfided through a liquid-phase sulfidation procedure and tested in hydrotreating of straight-run vacuum gasoil. It was shown that the Ni/Mo/W atomic ratio influenced the formation and composition of active compounds and had almost no influence on the textural properties of catalysts. The best hydrodesulfurization (HDS) activity was obtained for the catalyst with Ni/Mo/W ratio—1/0.15/0.85, while hydrodenitrogenation (HDN) activity of the catalysts is very similar.

The problem of optimizing the textural characteristics and chemical composition of the alumina support of a vacuum gasoil hydrotreating catalyst is considered. The catalyst is synthesized using the state-of-the-art environmentally friendly technology of flash calcination of gibbsite. Ways of increasing its specific surface area by introducing inorganic additives containing boron or sulfur at the stage of synthesizing boehmite with needle-shaped particles are developed. It is established that introducing such modifiers raises SBET by 50–100 m2/g, relative to the maximum values that can be attained by varying the standard parameters of hydrothermal treatment. It is shown that introducing boron at the stage of boehmite synthesis improves the catalytic activity of CoNiMoP catalyst in the hydrodesulfurization and hydrodenitrogenation of vacuum gasoil by two or more times, relative to a similar catalyst doped with boron from an impregnating solution.

The influence of textural characteristics of NiMo/Al2O3 on silicon capacity and hydrotreating activity has been investigated so as to develop guard-bed catalyst for silicon removal from middle distillates. Series of NiMo/Al2O3 catalysts with a specific surface area from 150 to 210 m2/g and an average pore diameter from 21.1 to 10.5 nm have been synthesized. The difference in textural characteristics has been achieved by variation of aging time and temperature of hydrothermal treatment of boehmites. The boehmites, supports and catalysts were studied by various physico-chemical methods: XRD, nitrogen adsorption-desorption, IR spectroscopy, UV–vis, 1H NMR, 27Al NMR, XPS, SEM, HRTEM. Catalysts were tested in hydrotreating of diesel fuel contaminated with decamethylcyclopentasiloxane as a model silicon compound. It is shown that the increase in aging time and temperature of hydrothermal treatment of initial boehmites results in the decrease of OH groups concentration per 1 g of an alumina support. The increase of the OH groups content leads to higher silicon capacity, while HDS activity of catalysts decreases. The study of catalysts surface after reaction showed that Si located on a support surface and did not cover directly active component particles. However, its location on the support near edges of active component particles could result in the decrease of HDS activity due to limited accessibility of the active sites.

CoMo-hydrotreating catalysts differed in the way of P addition were studied. The phosphorus was added in catalysts as follows: into the kneading paste of an alumina support, by impregnation of an alumina support before impregnation by active metals and into impregnation solution jointly with active metals. Impregnating solutions, supports and catalysts were studied by the nitrogen adsorption-desorption, UV–vis spectroscopy, RAMAN and ATR-FTIR spectroscopies, HRTEM, EDX, XPS. Catalysts were tested in hydrotreating of model feed. It was established that adding of P into the kneading paste or by impregnating of a support influenced negatively catalytic activity. Negative effect was caused by the formation of CoAl2O4 compounds and reduced portion of cobalt in the content of active phase. The addition of phosphorus into impregnation solution results in a significant increase in catalytic activity in the hydrodesulfurization of dibenzothiophene. In this case, phosphorous results in the change in the structure of active component precursors, the increase in the stacking number of the active component particles, the decrease in the interaction between active metals and a support. It was shown that the most efficient way to improve catalysts by P is to add its precursor into impregnating solution.

The effect of ultrastable zeolite Y recrystallization on the properties of NiMo/USY-Al2O3 hydrocracking catalyst has been studied. The mesoporosity, being introduced as the result of zeolite Y recrystallization, is mainly preserved at the subsequent steps of NiMo catalysts preparation. The total concentration of Bronsted acid sites in the catalysts varies proportionally to that for the corresponding zeolites used for preparation. It is observed that the higher the recrystallization degree the lower the concentration of strong Bronsted acid sites in the catalysts. UV–vis DRS, HRTEM and XPS data suggest that the state of supported Ni and Mo is similar for the catalysts prepared with parent and recrystallized zeolites. The catalysts based on recrystallized zeolites have significantly higher activity in hexadecane hydrocracking as compared to the catalyst obtained using parent zeolite. This effect is rationalized in terms of the improved accessibility of zeolite acid sites after recrystallization. Moreover, the mesoporosity introduced by zeolite Y recrystallization has a positive effect on the selectivity of NiMo/USY-Al2O3 hydrocracking catalyst.

Calcined CoMo/γ-Al2O3 hydrotreating catalysts were reactivated by a solution of citric acid and triethylene glycol. The reactivated catalysts were tested in HDS of dibenzothiophene and hydrotreating of SRGO. The reactivated catalysts were showed a significant increase in activity compared to calcined. The highest reactivation was observed for the sample reactivated using a solution of citric acid and triethylene glycol. All catalysts were characterized by means of UV-DRS, FTIR, Raman spectroscopy, XRD, XPS, and HTREM. It has been shown that the addition of triethylene glycol increases the proportion of CoMoS phase and the dispersion of sulfide particles.

Under discussion is optimization of texture and chemical composition of alumina as the support for the catalyst for hydrotreatment of vacuum gasoil synthesized using the environmentally friendly modern technology of flash thermal treatment of gibbsite. Approaches to increasing the specific surface area by introducing inorganic admixtures (including boron or sulfur) at the stage of synthesis of pseudoboehmite were developed. The introduction of these modifiers was established to increase SBET by 50–100 m2/g comparing to the maximal areas attaineddue to variation in the standard process parameters of the hydrothermal treatment. It was shown that the introduction of boron at the stage of pseudoboehmite synthesis resulted in no less than two times increase in the catalytic activity of CoNiMoP to hydrodesulfurization and hydrodenitrogenation against the activity of a similar catalyst with boron introduced with the impregnating solution.

NiMo/γ-Al2O3 protective-layer catalysts for removing silicon from diesel fractions were examined. The catalysts differ in the way in which boron is introduced into the support. The supports and catalysts were examined by X-ray diffraction analysis, transmission electron microscopy, IR spectroscopy, and adsorption–desorption of nitrogen. The catalysts were tested in hydropurification of the diesel fraction to which decamethylcyclopentanesiloxane was added as a model silicon compound. It was shown that introduction of boron into the support results in that the surface area of the supports and catalysts increases. If boron is introduced into pseudoboehmite, massive particles of the Ni–Mo–S phase are formed. It was found that the highest capacity for silicon is observed for the catalyst into which boron is introduced in the stage of pseudoboehmite preparation.

A series of low-sodium ultrastable Y zeolites (SiO2/Al2O3 ≈ 25) partially exchanged with different amounts of rare earth ions (RE2O3 = 0.55–3.32 wt%) was prepared and characterized by XRD, IR spectroscopy, elemental analysis, N2 adsorption, as well as 29Si and 27Al NMR. The effect of RE content on the number and relative strength of acid sites of REY zeolites was studied by IR spectroscopy of absorbed CO and pyridine. The increase in the RE content in the zeolites leads to a decrease in the concentration of strong Bronsted acid sites (BAS) in faujasite cages (bridged Si–O(H)–Al groups), especially the concentration of stronger BAS associated with Si–O(H)–Al groups polarized by extra-framework aluminum species. At the same time, the concentration of less acidic OH groups connected with extra-framework ions increases possibly due to the formation of additional RE–O(H)–Al groups. The total number of BAS in all the samples remains close. An increase in the RE2O3 content from 0.55 to 3.32 wt% decreases almost by half the ratio of strong BAS in faujasite cages to less acidic extra-framework BAS. The catalytic performance of NiMo/(30 wt% REY + 70 wt% Al2O3) catalysts was evaluated in hydrocracking of vacuum gas oil. The enhanced hydrocracking activity and selectivity to middle distillates are mainly achieved due to the optimal acidity of the zeolites.

A NiMoP/Al2O3 catalyst deactivated at the industrial plant was subjected to oxidative regeneration and reactivation with water and an aqueous solution of citric acid. The catalyst was studied at all stages by XRD, UV-vis, Raman spectroscopy, FTIR spectroscopy, XPS and HRTEM methods. The catalyst samples after oxidative regeneration, treatment with water and rejuvenation with citric acid were tested in hydrotreatment of the model feedstock and straight-run gasoil. It was established that the regenerated catalyst contained phosphorus strongly bound to the support and soluble or insoluble Ni and Mo compounds. The catalyst after water treatment contained only insoluble Ni and Mo compounds and a phosphate monolayer, while treatment with citric acid resulted in the formation of citrate complex compounds. Ni and Mo compounds in the sulfide form, which were obtained from insoluble components, showed high activity in the target hydrotreating reactions.

The possibility to increase the activity of CoMo/Al 2 O 3 catalysts in the desulfurization and denitrogenation of diesel fuel by introducing different amounts of phosphorus is studied. Phosphorus content in the catalysts was adjusted by addition of various amounts of H 3 PO 4 to the impregnating solution containing Co, Mo and citric acid. CoMo with 1 wt.% of P and 1 wt.% of B was also investigated. Catalysts were characterized by HCNS-analysis, nitrogen adsorption, XPS, HRTEM, UV–vis DRS and IR-spectroscopy of adsorbed CO. Catalysts were tested in hydrotreating of straight-run diesel fuel. It was found that the morphology and dispersion of the sulfide active component was independent to the phosphorus content in catalysts. Amount of CoMoS phase increased in catalysts, while the concentration of the surface P-OH groups and Lewis acid sites decreased. The catalyst with 1 wt.% of P and 1 wt.% of B had a maximal activity in desulfurization and denitrogenation reactions.

CoMoB/Al2O3 catalysts with up to 2 wt.% of B have been synthesized by two different methods an introduction of boron into γ-Al2O3 support during the kneading of the paste or by the impregnating of γ-Al2O3 extrudates by the solution of Mo and Co compounds, citric and boric acids. It is shown that the activity in HDS and HDN of diesel fuel increases with increasing boron content in catalysts. The growth of the activity is associated with the increase in CoMoS phase content, Co dispersity, an average slab length of sulfide active component particles and an average number of slabs per 1000 nm2. The positive effect of boron is much more pronounced for catalysts prepared by the introduction of boron to the solution, since boron is located preferentially on the surface of alumina particles.

Hydrocracking of vacuum gas oil was studied over micro-mesoporous zeolite based catalysts, obtained by zeolite Y recrystallization. The contribution of mesoporosity in recrystallized materials was varied by adjusting the content of alkali and the temperature of hydrothermal treatment. The increase of recrystallization degree results in the increase of mesopore to micropore volume of zeolite Y as well as to the decrease of the contribution of strong Bronsted acid sites in faujasite cages and the increase of the contribution of Bronsted acid sites in mesopores. The highest hydrocracking activity and middle distillates yield is achieved over NiMo catalyst obtained with micro-mesoporous material with low degree of recrystallization. This effect is due to the improved accessibility of active sites and easier transport of bulky molecules provided by mesopores, on the one hand, and optimal zeolitic acidity, on the other hand. The highest selectivity to middle distillates is achieved over catalyst with the highest degree of zeolite recrystallization. This observation can be explained by the decrease of the contribution of strong BAS (bridging Si-O(H)-Al groups) accompanied by the increase of concentration of BAS in mesopores.

In the present work, NiW/Al 2 O 3 catalyst was prepared with the use of citric acid and thermally treated at temperatures of 120, 220, 300 and 450 °C. It was shown that the thermal treatment at temperatures of 220–300 °C leads to decomposition of citrate ligands, 450 °C – to the almost complete removal of organic carbon. HRTEM of the sulfided catalysts showed that stacking number of WS 2 increases with the increase of the thermal treatment temperature while the WS 2 slab length has minimum at 220 °C. The results of XPS indicated that the sulfidation degree of tungsten and nickel decreases with the increase of the thermal treatment temperature. The catalyst thermally treated at 300 °C resulted to be most active in DBT HDS, quinoline HDN and naphthalene hydrogenation reactions. The higher activity of this catalyst in comparison with the samples thermally treated at 120 °C and 220 °C can be explained by an increased stacking degree of the sulfide WS 2 slabs while maintaining a small length of sulfide slabs and by a smaller carbon content that can impede access to the active sites. The calcination at 450 °C leads to low activity due to the low dispersion of the active component and a decrease in the degree of sulfidation of tungsten and nickel.

Methodological aspects of the screening of granular chromia–alumina dehydrogenation catalysts are discussed, along with ways of estimating their lifetime by treating catalysts in a steam–air medium. The efficiency of using small reactors (with diameters of less than four effective granule sizes) to compare the catalytic activities of catalysts at the screening stage is demonstrated by the example of Mg- and Zr-promoted chromia–alumina catalysts.

Absract CoMo/Al2O3-ASA catalysts with Mg were synthesized. Catalysts differed in the way of Mg addition: 1. Mg was added to ASA, 2. Mg was added to the kneading paste during the support preparation, 3. Mg was added before or after Co and Mo by the impregnation. Catalysts were characterized by the following techniques: low-temperature N2 adsorption, IR of CO and CO2 adsorption, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy. Synthesized catalysts were tested in hydrotreating of the model fluid catalytic cracking gasoline containing 250 ppm of sulfur from thiophene, 40 wt.% of toluene, 40 wt.% of heptane and 20 wt.% of n-hexene-1. It was found that the addition of Mg resulted in changes of physico-chemical properties of catalysts and their HDS and HYD activities. The way of Mg addition influenced the content of Lewis and Bronsted acid sites and morphology of sulfide active component. Mg increased HDS activity and decreased octane number loss. The catalysts with Mg in the kneading paste of the support and with Mg added after active metals showed the best combination of HDS activity and selectivity.

Commercial liquid-phase-sulfided type II CoMo/Al2O3 catalyst was reactivated after commercial operation and oxidative regeneration. For this purpose, the use of citric acid (CA) that reactivates a regenerated CoMo/Al2O3 catalyst was studied. The study of the reactivated catalyst was carried out by means of UV-DRS, FTIR, Raman spectroscopy, XRD, XPS, and HTREM. The catalytic activity was estimated in the HDS of straight-run gasoil (SRGO). It was shown that the treatment of the catalyst with CA leads to the formation of a Co–Mo complex compound and significantly reduces the proportion of β-CoMoO4 and MoO3 in the catalyst. Eventually, this leads to the formation of CoMoS phase type II in a higher proportion enhancing the HDS catalytic properties.

Ni-Mo bimetallic catalysts are prepared by impregnating a carrier containing amorphous aluminosilicate (AAS) and aluminum oxide using a solution with Ni, Mo, and citric acid. The temperature of the catalysts ranges from 120 to 550°С. The physicochemical properties of the catalysts are studied via XPS, TEM, and HCNS analysis, and they are tested in hydrocracking of vacuum gasoil. The particles of the sulfide active component (NiMoS phase) are localized predominantly on surfaces of aluminum oxide, and only some are on surfaces of AAS. When the temperature of catalyst calcination is raised, the average number of the layers in particles of the NiMoS phase grows as well, due to the removal of citric acid. This indicates strengthening of the interaction between the sulfide active component and aluminum oxide. The content of Ni-Mo massive sulfide particles also grows along with the temperature of calcination. The morphological characteristics of the sulfide active component affect the activity of the catalysts in hydrodesulfurization and hydrodenitrogenation, but not in hydrocracking. The optimum heat treatment temperature for NiMo/AAS-Al2O3 catalysts prepared with citric acid is 120°C. Recommendations are given for the heat treatment of catalysts under industrial conditions.

The effect of the W: (W + Mo) atomic ratio in NiMoW trimetallic catalysts on their catalytic and physicochemical properties is studied. The catalysts are prepared by impregnating a carrier containing amorphous aluminosilicate (AAS) and aluminium oxide with an aqueous solution containing Ni, Mo, W compounds, and citric acid. They are studied via XRF, TEM, NH3 TPD, and low-temperature nitrogen adsorption and are tested in the hydrocracking of vacuum gasoil (VGO). The average length of a sulfide active component layer shrinks as the amount of Mo increases and the amount of W in the catalyst is reduced. XPS data indicate that the degree of sulfidation of tungsten in NiMoW trimetallic catalysts is lower than in NiW catalyst. Testing of the catalysts in hydrocracking of a straight-line VGO at 390–420°C, 16 MPa, a feedstock hourly space velocity (FHSV) of 0.71 h−1, and a H2: VGO ratio of 1200 L/L shows the activities of hydrodesulfurization, hydrodenitrogenation, hydrogenation, and hydrocracking grow along with the W: (W + Mo) ratio. When the process pressure is high and the amount of sulfur in the NiW feedstock is low, the catalysts have higher activity in the target reactions of VGO hydrocracking than NiMo catalyst.

The influence of the order of catalysts and their ratio in the bed for FCC feedstock hydrotreatment was investigated. CoMo/Al2O3 and NiMo/Al2O3 catalysts were prepared in the laboratory and studied by nitrogen adsorption–desorption, XPS and HRTEM methods. The catalysts were tested in hydrotreatment of model feedstocks. It was found that NiMo/Al2O3 catalyst had the highest activity in conversion of the model feedstock containing sulfur and nitrogen compounds. The best results were obtained for the feedstock firstly treated by NiMo/Al2O3 and then by CoMo/Al2O3. Catalysts were tested separately and together in hydrotreatment of SRVGO. The order of catalysts and their ratio were varied. The best combination included NiMo/Al2O3 catalyst at the top of the reactor and CoMo/Al2O3 at the bottom of the reactor in the ratio of 40/60 vol%.

The hydroconversion of high-sulfur oil shale in the presence of natural mineral matrices: shale ash, sandstone, and clay has been investigated. It has been shown that mineral matrices containing clays and iron exhibit catalytic activity during the hydroconversion of oil shales. Due to this activity, a significant reduction in the sulfur and nitrogen content and an increase in the amount of light fractions in the resulting synthetic oil are achieved.

The influence of various characteristics of NiMo/Al2O3 guard-bed catalysts on their activity in the removal of silicon from the diesel fraction has been studied. It has been shown that an increase in the Ni and Mo content leads to a decrease in the amount of trapped silicon in the samples, thereby enhancing the activity of the catalysts in hydrodesulfurization. It has been found that catalysts with an average pore diameter above 130 A have the highest silicon-trapping activity.

Effect of various chelating components, multibasic carboxylic acids and glycols, used to prepare hydrotreating catalysts on the activity regeneration of calcined hydrotreating catalysts was studied. Reactivated catalyst samples were tested in a model reaction of hydrodesulfurization of dibenzothiophene. It was shown that the treatment of calcined catalysts with the chelating components leads to an increase in the catalytic activity. The best catalytic characteristics are observed for the catalyst reactivated with a solution containing citric acid and triethylene glycol.

A new CoMo catalyst for selective hydrotreating of FCC gasoline has been developed; the catalyst is intended for the production of hydrotreated gasoline with up to 10 ppm of sulfur and with a research octane number decreased by less than 1.0. The new catalyst allows hydrotreating of FCC gasoline without its preliminary separation into the light and heavy fractions. The hydrotreating conditions were as follows: hourly space velocity 2.2 h–1, temperature 270°C, pressure 2.5 MPa, H2/feed = 150 m3/m3. The high degree of hydrodesulfurization at minimum decrease in the octane number is achieved due to the high activity of the developed catalyst in hydrodesulfurization of the sulfur-containing components of the feedstock and conversion of reactive high-octane olefins of FCC gasoline into less reactive derivatives with high octane numbers. The catalyst is a CoMoS phase deposited on a support containing amorphous aluminosilicate and γ-Al2O3. The method for the preparation of the catalyst is adapted to the equipment of Russian plants and feedstocks. The parameters of hydrotreating using this catalyst ensure the hydrotreating of FCC gasoline to a residual sulfur content of less than 10 ppm with minimum redesign of the equipment currently available at Russian refineries.

The results from industrial tests of technology developed earlier for the reactivation of CoMo/Al2O3 catalyst for the deep hydrotreating of diesel fuel, including the oxidative regeneration of the catalyst with subsequent treatment using organic complexing agents, are presented. Samples of the catalyst, fresh and at different stages of its reactivation, are investigated using a set of analytical and physicochemical methods. The chemical composition, textural characteristics, mechanical strength, structure of the active sulfide component (TEM, XPS) are determined. Catalytic tests are performed that include lifetime tests (360 h) in the hydrotreatment of a straight-run diesel fraction. The restoration of the physicochemical and catalytic properties is observed for a sample subjected to oxidative regeneration with subsequent treatment using organic complexing agents. An industrial batch of deep hydrotreatment catalyst reactivated by this technology is loaded into an L-24-6 industrial plant facility and ensures stable purification of straight-run diesel fuel containing up to 10% of light catalytic cracking gas oil to a residual sulfur content of less than 10 ppm. Comparison of the obtained results and data on the industrial operation of fresh catalysts shows that the technology developed by the Institute of Catalysis and PAO Gazprom Neft ensures almost complete restoration of the properties of the deactivated catalysts.

CoMo-catalysts modified by boron were studied. Boron was added to alumina support by kneading. Supports and catalysts were characterized by nitrogen adsorption, XPS, IR-spectroscopy of adsorbed CO. Catalysts were tested in hydrotreating of straight-run diesel fuel with 5 vol.% catalytic cracking gasoil (initial S content was 2750 ppm). It is found that boron has no significant influence on textural characteristics of catalysts. However, it increases slab length and visualization degree of active component, while stacking number remains unchanged (preferential formation of monolayers). Difference in morphology is caused by changes of Lewis acidity and generation of Bronsted acid sites. It is found that all catalysts with boron provide production of ultra-low sulfur diesel fuels (less than 10 ppm). The catalyst with a boron content of 2 wt.% combines high activity in HDS and HDN.

The effect of the addition of boric and phosphoric acids to impregnating solutions on the structure and properties of NiMo catalysts for VGO hydrotreating was studied. The catalysts contained a wide-porous support on the basis of a mixture of γ- and δ-Al2O3 phases. The catalysts were studied by XRD, HRTEM, IR CO, ATR-FTIR, XPS. The catalytic activity was evaluated in hydrotreating of heavy VGO. It is established that the NiMo-citrate complex is formed in impregnating solutions. At the same time, the introduction of phosphoric and boric acids into NiMo-citrate complex solution does not lead to a distortion of the complex compound structure. It has been found that calcining of the support at 900 °C makes it possible to obtain a mixture of gamma and delta phases. It was determined that phosphoric and boric acids react with OH groups of the support, but the introduction of phosphoric acid leads to the formation of P OH groups on the surface. The presence of P and/or B in a catalyst composition results in an increase in the number of MoS2 layers in a slab. However, with the introduction of B, a small decrease in the amount of Mo on the surface of a catalyst in the form of Mo4+ is observed. The change in textural and acid characteristics allows us to conclude that bulk particles of BO3 are formed. Testing of catalysts in hydrotreating of heavy VGO made it possible to establish that the introduction of B into composition of the impregnating solution significantly reduces the activity of the catalysts in hydrotreating, while the introduction of phosphorus leads to an increase in the activity of a catalyst. The introduction of phosphoric and boric acids into the impregnating solution simultaneously increased the activity of the catalyst as compared to the sample containing boron only.

Hydrocracking of vacuum gas oil has been studied over NiMo/zeolite-Al2O3 catalysts. Three different zeolites have been used for catalysts preparation: zeolites Beta (BEA) and Y (FAU) having small crystal size and zeolite Y modified by recrystallization (RFAU). HRTEM, low-temperature N2 adsorption, FTIR of adsorbed CO and TPD-NH3 showed that zeolites had different crystal sizes, mesopore volume, strength and concentration of acid sites. Sulfide active component particles have been revealed to be similar in all catalysts by HRTEM and XPS. NiMo/BEA catalyst having zeolite with the smallest average particle size and the highest concentration of Bronsted acid sites (BAS) demonstrated the highest hydrocracking activity. Selectivity to middle distillates decreased in the following order: NiMo/FAU > NiMo/RFAU > NiMo/BEA. This effect is accounted for by optimal zeolite acidity and improved availability of the acid sites for bulky molecules of the heavy feedstock.

The positive effect of alumina surface graphitization by CVD with ethylene on the activity of CoMo catalysts in hydrodesulfurization has been demonstrated. X-ray diffraction, Raman spectroscopy, High-resolution transmission electron microscopy, X-ray photoelectron spectroscopy and nitrogen physisorption showed that alumina surface graphitization does not significantly change the morphology and textural characteristics of the support. However, it has a significant impact on the morphology of supported sulfide component resulting in the formation of particles with a shorter slab length (2.9 vs 3.3 nm) and higher stacking number (2.4 vs 2.1) as compared to the sample based on γ-Al2O3. The results of CoMoS/γ-Al2O3 and CoMoS/C@γ-Al2O3 catalysts testing in hydrotreating reactions demonstrated a similar activity in hydrodenitrogenation of quinoline and 1.7 times higher activity of CoMoS/C@γ-Al2O3 in hydrodesulfurization of dibenzothiophene. Higher hydrodesulfurization activity of CoMoS/C@γ-Al2O3 sample is attributed to improved dispersion of the supported sulfide component and enhanced promotion of MoS2 by cobalt. Thus, the simple CVD approach presented here allows selective modification of the surface of commercially available alumina supports with a layer of graphite-like carbon and can be used to improve the activity of conventional hydrotreating catalysts.

Influence of Si addition at the stage of boehmite preparation on properties of NiMo/Al2O3 catalysts for FCC feedstock pretreatment have been studied. The series of boehmites doped by PDMS at the stage of hydrothermal treatment was prepared. Si/Al molar ratio was 0, 0.01, 0.015 and 0.02. Boehmites were used for supports and catalysts preparation. Boehmites, supports and catalysts have been characterized by XRD, TGA, nitrogen adsorption-desorption, IR spectroscopy, UV–Vis, 29Si MAS NMR, HRTEM, EDX, XPS. Catalysts were tested in hydrotreating of FCC feedstock. It is shown that there are changes in morphology of boehmite particles and textural characteristics of aluminas. Introduction of Si to alumina induces formation of wider mesopores and blocks part of the Lewis acid sites of alumina. Testing of catalysts in hydrotreating of FCC feedstock shows that the catalyst with Si/Al ratio of 0.01 in boehmite has the best combination of hydrodesulfurization and hydrodenitrogenation activities.

Bifunctional catalysts Pd/ASA-Al2O3, Pd/Y-ASA-Al2O3, Pd/Beta-ASA-Al2O3, Pd/ZSM-23-ASA-Al2O3 were prepared. Catalysts were characterized by FTIR of adsorbed CO, nitrogen adsorption and CO chemisorption. Average sizes of palladium particles in the catalysts were found to be 1.2–2.9 nm. Zeolite-based catalysts contained stronger Bronsted acidic sites than amorphous silica-alumina (ASA) based catalyst Pd/ASA-Al2O3. Catalysts were tested in hydroconversion of hydrocracker bottom (HCB). Hydrocracking activities of Pd/Y-ASA-Al2O3 and Pd/Beta-ASA-Al2O3 catalysts were found to be significantly higher than that of Pd/ASA-Al2O3 and Pd/ZSM-23-ASA-Al2O3 catalysts. Conversion of 80% of HCB was achieved for catalysts with zeolites beta and Y at 250 °C. It was found that selectivity to middle distillates increases in following order: Pd/ZSM-23-ASA-Al2O3

Trimetallic Co-Ni-Mo catalysts with different Co and Ni content (Co 3 Ni 0 , Co 1.8 Ni 1.2 , Co 1.5 Ni 1.5 , Co 1.2 Ni 1.8 and Co 0 Ni 3 ) were studied. Catalysts were characterized by HRTEM, XPS, EXAFS and XANES methods. It was shown that all catalysts contain metals preferentially in the form of sulfide active component with the structure that is similar to Co-Mo-S phase. Co-Mo and Ni-Mo catalysts contain active component in the form of Co-Mo-S and Ni-Mo-S phases respectively. Trimetallic catalysts were shown to contain mixed Ni-Co-Mo-S phases. Catalytic tests showed that the catalyst with 1.8% Co, 1.2% Ni and 10% Mo has the highest activity in hydrotreating of VGO. The highest activity of the catalyst is proposed to be provided by the formation of mixed Ni-Co-Mo-S phase.

The method for preparation of Co–Mo catalysts for one-stage hydrotreating of full FCC gasoline fraction is proposed. The main characteristic of the catalysts is the use of the supports based on amorphous aluminosilicate. Catalysts were characterized with nitrogen adsorption-desorption, HRTEM and XPS methods. It was shown that all catalysts containing aluminosilicates have similar textural characteristics and contain Co-Mo-S phase with similar morphology. The IR CO data indicate that sulfided catalysts contain different acid sites with the predominance of weak Lewis acid sites and Bronsted acid sites with the strength of 1190 kJ/mol. Catalysts were tested in hydrotreating of model fuel and full FCC gasoline fraction. It was shown that presence of amorphous aluminosilicates in catalysts results in the increase of catalytic activity in reactions of olefin isomerisation. Significant contribution of olefin isomerization reactions results in the prevention of octane number loss while high activity hydrodesulfurisation maintains.