Hydrocracking Catalysts Research Articles

Ni/CNT/Zeolite-Y composite catalyst for efficient heptane hydrocracking: Steady-state and transient kinetic studies

The effect of integrating carbon nanotubes (CNTs) into a bi-functional Ni-Zeolite-Y catalyst was studied for the hydrocracking of heptane at 350 and 400 °C (total pressure of 5 bar). It was shown that the growth of CNTs on the surface of Ni-Zeolite-Y (Ni-ZY) results in enhanced stability and catalytic activity (conversion increased by 22% at 350 °C) compared to the conventional Ni-ZY. A significant increase in the initial transient kinetic rates of CH4 and C2H6 formation was also noticed. The CNT/Ni-ZY also showed reduced coke formation during the reaction as entailed by transient isothermal (400 °C) oxidation experiments. The formation of a crystalline NixCy phase on the zeolite surface was observed in the case of CNT/Ni-ZY, potentially responsible for its enhanced catalytic performance. This work demonstrates that the integration of CNTs in hydrocracking catalysts offers new opportunities for enhancing their catalytic activity, selectivity and coking resistance.

Effect of Zeolite-Y Modification on Crude-Oil Direct Hydrocracking.

To study the role of modified zeolite-Y-based hydrocracking catalyst in crude-oil hydroconversion, various hydrocracking catalysts were synthesized with various zeolites. The zeolites and catalysts were characterized with nitrogen adsorption (N2-adsorption), small-angle X-ray scattering, X-ray powder diffraction (XRD), wavelength-dispersive X-ray fluorescence, and the ammonia temperature-programmed desorption (NH3-TPD). Their reaction performance was evaluated with crude oil under commercial hydrocracker operating conditions in a pilot plant unit. The results showed that the catalysts with high acidity, strong acid sites, and mesopores can enhance the crude conversion. The acidity and mesoporosity of the zeolite and the catalysts play critical roles in determining the catalyst performance.

Extraction of molybdenum from spent NiMo hydrocracking catalysts assisted by ionizing radiation

A catalyst is a substance that changes the rate of a reaction. In the petroleum industry, the catalysts are commonly used for fluid catalytic cracking and hydrocracking carried out with catalyst, each of them applied in a specific stage. These catalysts are used to facilitate the molecular chains cracking, which will generate a mixture of hydrocarbons. However, the catalyst gradually loses its activity, either by changing its original molecular structure or by its contamination from other petroleum molecules. The application of ionizing radiation (medium-energy electron beam) over these spent catalysts was studied to contribute the extraction of metals or rare-earths of high added-value. Tests conducted with hydrocracking catalysts were used the technique of electron beam irradiation (1.3 MeV) and had as a subject the extraction of molybdenum. Energy Dispersive X-ray analysis was performed on a Shimadzu EDX-720/800HS and X-ray Diffraction analysis on a Rigaku MultiFlex. Electron beam irradiation had a positive contribution if compared to traditional thermal and chemical methods. In temperature around 750 °C, hydrocracking irradiated catalysts of the lower region have an extraction of molybdenum (MoO3) yield twice higher compared to non-irradiated ones, in other words 57.65% and 26.24%, respectively.

Influence of the Borate on the Performance of ASA-Al2O3 supported Ni-Mo Hydrocracking Catalyst

The borate-doped and non-borated Ni-Mo/ASA-Al2O3 catalysts have been prepared and characterized by the BET, XRD, TGA, and NH3-TPD analysis. The catalyst’s performance was assessed in n-hexadecane hydrocracking using a downflow fixed bed micro-reactor. The stability of the catalysts in the presence of water and coke deposition was examined for the HCK of non-conventional feeds. The obtained results revealed that borate increased the feed percentage conversion from 91.43 to 99.21% compared to the not borated catalyst. This improvement is mostly due to the promotion of the acidic functions by BO3 addition. Results showed that the addition of borate increased the selectivity of light hydrocarbons and light gaseous products slightly (from 4.64 to 8.76%).

Mesoporous Silica from Parangtritis Beach Sand Templated by CTAB as a Support of Mo Metal as a Catalyst for Hydrocracking of Waste Palm Cooking Oil into Biofuel

In this study, natural source Parangtritis beach sand was extracted into mesoporous silica (MS). Synthesis of mesoporous silica (MS) was carried out at sodium silicate: CTAB ratio of 1:0.5 (w/w). Monometallic catalyst was used to improve the performance of the catalyst. The monometallic used was Mo metal, which was synthesized using the wet impregnation method. Catalysts were characterized using FTIR, XRD, Surface Area Analyzer (SAA), SEM–EDX, and TEM. MS has pore diameters and surface area of 2.62 nm and 897.3 m2/g, respectively. Mo/MS has pore diameters, surface area, and Mo metal concentration of 2.46 nm, 593 m2/g, and 4.75%, respectively. Catalytic activity and selectivity were evaluated in hydrocracking of waste palm cooking oil at 500, 550, and 600 °C, and catalyst: waste palm cooking oil ratio of 1:100, 1:200, and 1:300. The best catalyst will be tested for reusability 3 times through the hydrocracking process. Mo/MS produces better liquid products and hydrocarbon compounds than MS. The results of the conversion of liquid products analyzed using GCMS. The yield of liquid products obtained in the hydrocracking of waste palm cooking oil using Mo/MS with the optimum temperature and the weight ratio of catalyst: feed at 550 °C and 1: 300 was 66.99 wt.% with consists of hydrocarbon compound as 62.79 wt.%. The yield of liquid products obtained in the hydrocracking waste palm cooking oil using the used Mo/MS catalyst in the last run was 80.26 wt.% with consist of hydrocarbon compound as 74.13 wt.%.Graphic Abstract

Role of zeolite content in Ni-Mo/β-USY zeolite catalyst on hydrocracking of n-hexadecane and vacuum gas oil in a batch reactor and a fixed-bed reactor

In this paper, different materials that involved amorphous silica–alumina and hydrothermally synthesized beta zeolite and treated Y zeolite (USY) were introduced as parts of the hydrocracking catalyst supports. The prepared supports were used for preparation of Ni-Mo/silica alumina–zeolite catalysts by wetness impregnation method. The prepared catalysts were characterized by BET, temperature programmed desorption (TPD), temperature programmed reduction (TPR), and field emission – scanning electron microscopy (FE–SEM) methods. Effect of zeolite type and content on hydrocracking of n-hexadecane and vacuum gas oil in a batch and a fixed-bed reactor was investigated. Also, the content of coke formed after reaction was measured by thermal gravimetric methods (TGA). Hydrocracking was done at 400 °C and 55 bar. The hydrocracking of vacuum gas oil results showed that in the Ni-Mo/10B-30USY catalyst containing higher USY zeolite with high total acidity, selectivity to middle distillate was higher than the other (90%). Moreover, the Ni-Mo/10B-30USY catalyst in hydrocracking of n-hexadecane had a higher yield (82%) and was more selective to heavier products (C9–C12). The findings indicated that in the Ni-Mo/10B-30USY catalyst, coke content was more than the other due to high acidity.

Impact of Feedstock Properties on the Deactivation of a Vacuum Gas Oil Hydrocracking Catalyst

The aim of this study was to understand the impact of vacuum gas oil (VGO) properties on the deactivation rate of a hydrocracking catalyst (nickel–molybdenum sulfide dispersed on a carrier containing USY zeolite). For this purpose, two hydrotreated feeds of different densities, organic nitrogen (∼120–150 ppmw) and aromatic content, were hydrocracked under operating conditions that favor catalyst deactivation, that is, high temperature (T = 418 °C) and high space velocity (LHSV = 3 h–1). The catalyst performance was followed by measuring the VGO conversion (370 °C+ petroleum cut) and determining the apparent kinetic constants for the main hydrocracking reactions (cracking, hydrodenitrogenation, hydrodesulfurization, and aromatics hydrogenation). The experiments were stopped after different times on stream (either 6 or 30 days) in order to assess the evolution of the catalyst as a function of time. The spent catalysts, obtained from three different reactor locations, were characterized by elemental and textural analyses and by thermogravimetry to investigate the quantity and nature of the coke formed. Catalytic tests with different model compounds (toluene and n-heptane) were carried out to determine the residual activity of the hydrogenating and acid catalyst functions. It was found that, at the evaluated conditions, both the nature and the content of organic nitrogen and aromatics compounds of the feedstock have a determinant role in the deactivation rate. Organic nitrogen determines the ratio between available metal and acid sites. The aromatics generate coke precursors on the available acid sites. Both factors play a coupled role that promotes coke deposition on the catalyst surface, which leads to an increase in the deactivation rate on top of the end boiling point of the feed.

Insights in the phenomena involved in deactivation of industrial hydrocracking catalysts through an accelerated deactivation protocol

A representative accelerated experimental deactivation procedure was developed to understand the activity loss of bifunctional vacuum gasoil (VGO) hydrocracking catalysts over time. Experiments were performed in an up-flow fixed-bed pilot unit with a typical vacuum gas oil feedstock. The deactivation was measured by tracking the decrease of VGO conversion (370 °C+) with time on stream. The catalyst consisted of nickel-molybdenum sulfide particles dispersed on a carrier containing USY zeolite. The impact of temperature, liquid hourly space velocity (LHSV), hydrogen to hydrocarbon (H2/HC) ratio and organic nitrogen (Norg) on the catalyst deactivation rate was first studied. The variables with the most significant impact on conversion loss were temperature and space velocity. Temperature directly influences the production rate of coke precursors, whereas space velocity affects the local concentration of feed contaminants along the reactor. Based on these results, the following operating conditions were selected to establish the final accelerated deactivation experimental protocol: T = 418 °C, LHSV = 3 h−1, H2/HC = 1500NL/L, P = 14 MPa, organic nitrogen content (Norg) = 150 ppm weight, total nitrogen content = 2500 ppm weight and a total time on stream of 30 days. Spent samples from this procedure presented similar properties to some industrial catalysts submitted to cycle lengths between 12 and 18 months. Both types of samples yield similar values of surface area and pore volume loss as well as a similar amount and nature of coke deposits. These results led to the qualitative validation of the protocol representativeness. This experimental procedure was then used to get more insight into the deactivation phenomenon. It was found that the organic nitrogen content of the feedstock is crucial, as it determines the ratio between available metal and acid sites. This ratio determines the reactions that take place and, therefore, the type of coke produced.

Activity of Ni-NH<sub>2</sub>/Mesoporous Silica Material as Bifunctional Catalyst for Hydrocracking of Used Cooking Oil

Synthesis of Ni-NH2/mesoporous silica bifunctional catalyst for conversion of used cooking oil into biofuel was carried out. The impregnation of Ni into the MS8 with a specific surface area of 666.6 m2/g, volume pore of 0.46 cm3/g, and diameter pore of 4.9 nm was done by wet impregnation method. The functionalization of NH2into the MS8 and Ni/MS8 was done by the grafting method. The catalytic activity test in used cooking oil hydrocracking was done by thermal (without catalyst), catalyst physical mixture of Ni/MS8 and NH2/MS8, and Ni-NH2/MS8 bifunctional catalyst. The results showed that the Ni/MS8 catalyst with acidity values ​​of 12.804 mmol/g was successfully modified with amine groups to produce Ni-NH2/MS8 bifunctional catalyst. This catalyst was utilized in the hydrocracking process of used cooking oil to produce the highest liquid product of 92.85 wt.% with the selectivity of gasoline and diesel fractions of 4.04 and 63.35 wt.% respectively.

Polymer-based bifunctional catalysts for anthracene hydrocracking in the medium of supercritical propanol-2

In this work, novel bifunctional catalysts based on the polymeric network of hypercrosslinked polystyrene were developed for the process of anthracene hydrocracking in the medium of supercritical propanol-2. The synthesized catalysts contain NiOOH as an active phase and the SiO2 as Brønsted acid sites supported on the highly porous support. The influence of the synthesis method and silica precursor type on the textural properties and the active phase composition was studied. The catalyst obtained by the hydrothermal method using tetraethoxysilane as a silica precursor seems to be the most optimal providing both high surface area, bimodal pore size distribution, and high acidity, and, thus, higher catalytic activity in anthracene hydrocracking.

Enhancing the activity of MoS2/SiO2-Al2O3 bifunctional catalysts for suspended-bed hydrocracking of heavy oils by doping with Zr atoms

Developing catalysts with not only hydrogenation activity but also cracking activity is very important for the advancement of suspended-bed hydrocracking technology. Within this respect, MoS2/SiO2-Al2O3 bifunctional catalyst is a kind of typical catalysts with both hydrogenation and cracking activity. Herein, a series of Zr-doped SiO2-Al2O3 mixed oxides were synthesized by a sol-gel coupled with hydrothermal method. The synthesized mixed oxides were characterized for chemical structures and acidic properties. It is found that doping SiO2-Al2O3 with Zr atoms significantly increases the numbers of acidic sites. The Zr-doped SiO2-Al2O3mixed oxides were then combined with dispersed MoS2, which was in-situ produced from oil-soluble Mo precursors, to fabricate a novel kind of bifunctional catalysts for suspended-bed hydrocracking of heavy oils. Owing to the significantly increased numbers of acidic sites in Zr-doped SiO2-Al2O3 mixed oxides, corresponding bifunctional catalysts demonstrate much enhanced activity for suspended-bed hydrocracking of heavy oils in relative to MoS2/SiO2-Al2O3 bifunctional catalysts.

Hydrocracking of Waste Palm Cooking Oil into Hydrocarbon Compounds over Mo Catalyst Impregnated on SBA-15

The highest activity and selectivity results were achieved in the presence of Mo metal supported by SBA-15. Mo/SBA-15 catalyst was synthesized using the wet impregnation method. Catalysts were characterized using FTIR, XRD, Surface Area Analyzer (SAA), and SEM-EDX. Mo/SBA-15 has pore diameters, surface area, and Mo metal concentration of 561.4 m2/g, 6.53 nm, and 4.41%, respectively. The hydrocracking process was carried out at a temperature of 500 °C with a ratio of catalyst: feed weight 1: 100. The best catalyst for hydrocracking of waste palm cooking oil was Mo/SBA-15. The presence of Mo metal is role play in the hydrocracking process because it can increase the activity and selectivity of the catalyst. In addition, decreased pore diameter and surface area also affect the hydrocracking process. The total liquid product produced by the Mo/SBA-15 catalyst was 53.86 wt.%. The results of the conversion of liquid products analyzed using GC-MS showed a total hydrocarbon compound of 50.35 wt.%. The fraction of gasoline produced was 42.46 wt.% and the fraction of diesel fuel produced was 7.89 wt.%.

The effect of Si/Al ratio of zeolite Y in NiW catalyst for second stage hydrocracking

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 Brønsted 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.

Dealuminated and Desilicated Natural Zeolite as a Catalyst for Hydrocracking of Used Cooking Oil into Biogasoline

<p align="justify">The modification of natural zeolite has been conducted by dealumination and desilication using HCl and NaOH treatments as a catalyst for hydrocracking of used cooking oil into biogasoline. This research aimed to study the effect of dealumination and desilication on the natural zeolite activity and selectivity of a hydrocracking process. A variety of catalysts was prepared by applying 3, 6, and 9 M HCl in the dealumination of natural zeolite to produce DNZ(3-1), DNZ(3-2) DNZ(3-3), DNZ(6-1), DNZ(6-2), DNZ(6-3), DNZ(9-1), DNZ(9-2), and DNZ(9-3) catalysts and NaOH in the desilication of natural zeolite to obtain NZB catalyst. The results showed that the dealumination and the desilication treatments affected the liquid product conversion of used cooking oil from catalytic hydrocracking. The hydrocracking of used cooking oil with NZB catalyst produced the highest gasoline fuel conversion of 94.87%. </p><p align="justify"> </p><p align="justify"> </p>

Structure and activity of unsupported NiWS2 catalysts for slurry phase hydrocracking of vacuum residue: XAFS studies

The catalytic activities of the dispersed NixW(1−x)S2 catalysts were investigated for hydrocracking (HCK) of vacuum residue (VR) at 693 K, 9.5 MPa H2 with the same amount of catalyst loading of 0.113 mmol as a metal basis. The catalysts were prepared in situ in the reaction using nickel acetylacetonate and tungsten hexacarbonyl as Ni and W precursors, respectively. Structural properties of the dispersed catalysts were characterized by extended X-ray absorption fine structure and transmission electron microscopy, which confirmed the formation of a well-dispersed NixW(1−x)S2 phase in the size range 8–10 nm. Moreover, it was demonstrated that the bimetallic metal sulfides of NixW(1−x)S2 feature promotional activity in the VR HCK, showing higher turnover frequency values and less coke formation in VR HCK than monometal sulfides.

Fibrous zeolite catalyst for hydrocracking.

Fibrous zeolite catalyst for hydrocracking.

Slurry-Phase Hydrocracking of a Decalin–Phenanthrene Mixture by MoS2/SiO2–ZrO2 Bifunctional Catalysts

Slurry-phase hydrocracking is one of the most advanced technologies for the conversion of inferior heavy oil to light fuel oil. In this work, MoS₂ was combined with SiO₂–ZrO₂ mixed oxides to offer a new class of bifunctional catalysts for slurry-phase hydrocracking. In the bifunctional catalysts, SiO₂–ZrO₂ mixed oxides with abundant mesopores and acid sites act as cracking catalysts. They were presynthesized by a sol–gel-hydrothermal method and systematically characterized by X-ray diffraction (XRD), N₂ adsorption, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), NH₃-temperature programed desorption (NH₃-TPD), and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The effect of Si/Zr molar ratios on the chemical structure, especially the acid properties of SiO₂–ZrO₂ mixed oxides were examined. Subsequently, a mixture of decalin–phenanthrene was selected as the model system to investigate the performance of bifunctional catalysts. It was found that the conversions of decalin and phenanthrene were significantly improved for MoS₂/SiO₂–ZrO₂ bifunctional catalysts. Further analysis indicated that the Bronsted acid sites of SiO₂–ZrO₂ mixed oxides played an important role in the improvement of decalin and phenanthrene conversions.

Influence of zeolite content in NiW/Y-ASA-Al2O3 catalyst for second stage hydrocracking

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 Brønsted 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%.

Optimization of Supports in Bifunctional Supported Pt Catalysts for Polystyrene Hydrocracking to Liquid Fuels

A series of bifunctional platinum catalysts were prepared, supported on alumina or different zeolites, some of which were submitted to either desilication or dealumination in order to modify their acidic properties. The catalysts were characterized for their structural and textural properties, their acidic properties, including distribution of acid strength and Bronsted and Lewis acidity, their metallic properties, and used in the hydrocracking of polystyrene under kinetic control, where activity in end-of-chain scission and random scission of the polymer has been quantified as well as the distribution of products. Activation energies and pre-exponential factors have been calculated from the kinetic data, and analyzed in terms of compensation effect, in order to extract conclusions on activity, active centers and reaction pathways. Finally, activation energies, both of end-of-chain and random scissions, yield to gasoline fraction and percentage of aromatics in the gasoline fraction have been correlated with catalytic properties in order to extract conclusions on the major catalytic properties affecting catalytic performance in this process, from the point of view of catalytic design.

Practical Application of Hierarchical Beta Zeolite in a Vacuum Gas Oil Hydrocracking Catalyst

AbstractA hierarchical Beta zeolite has been successfully mass‐prepared hydrothermally and dynamically in a pilot‐scale autoclave by an economical and simple process with low‐cost raw materials. The characterization results indicated that the pilot‐scale hierarchical Beta zeolite has the same textural, structural, and acidic properties like the bench‐scale sample. Moreover, the catalyst composed of the pilot‐scale hierarchical H‐Beta zeolite showed higher activity and selectivity to the middle distillate than that containing microporous Beta zeolite in catalytic hydrocracking of vacuum gas oil (VGO) evaluated by an industrial pilot installation in running of 3000 h, due to the increased accessibility and the reduction of diffusion constraint of large molecules to acid sites in the Beta zeolite framework.