Conversion Of Vacuum Gas Oil Research Articles

Effect of Residual Cuts on Deactivation of Hierarchical Y Zeolite-Based Catalysts during Co-Processing of Vacuum Gas Oil (VGO) with Atmospheric Residue (ATR)

The influence of residual cuts on the deactivation of hierarchical Y zeolite-based catalysts during the co-processing of vacuum gas oil (VGO) with atmospheric residue (ATR) was investigated. The experiments were conducted in a laboratory-scale MAT-type reactor. The conversion of VGO, ATR, and their 70:30 (mass basis) mixture was examined using two composite catalysts: Cat.Y.0.00 and Cat.Y.0.20. The operating conditions closely resembled those of the commercial catalytic cracking process (550 °C and contact times of 10 to 50 s). When ATR was processed individually, the conversion remained below 50 wt%. However, significant improvements in conversion rates were achieved and catalyst deactivation was mitigated when ATR was co-processed with VGO. Notably, the BET surface area and average mesopore volume were adversely impacted by ATR, which also led to the accumulation of high levels of metals and nitrogen on the spent catalyst, detrimentally affecting its acidic and structural properties. Moreover, substantial coke deposition occurred during ATR cracking. The soluble and insoluble coke analysis revealed H/C ratio values of up to 0.36, indicative of polycondensed coke structures with more than ten aromatic rings. The nature of the coke was confirmed through TPO and FTIR analyses. Interestingly, the CatY.0.20 catalyst exhibited less activity loss, retaining superior acid and structural properties. Co-processing Colombian atmospheric residue with ATR loadings of 30 wt% (higher than the typical 20 wt%) in catalysts formulated with hierarchical zeolites presents a promising alternative for commercial applications. This research opens avenues for optimizing catalytic cracking processes.

Roles of Catalysts and Feedstock in Optimizing the Performance of Heavy Fraction Conversion Processes: Fluid Catalytic Cracking and Ebullated Bed Vacuum Residue Hydrocracking

Petroleum refining has been, is still, and is expected to remain in the next decades the main source of energy required to drive transport for mankind. The demand for automotive and aviation fuels has urged refiners to search for ways to extract more light oil products per barrel of crude oil. The heavy oil conversion processes of ebullated bed vacuum residue hydrocracking (EBVRHC) and fluid catalytic cracking (FCC) can assist refiners in their aim to produce more transportation fuels and feeds for petrochemistry from a ton of petroleum. However, a good understanding of the roles of feed quality and catalyst characteristics is needed to optimize the performance of both heavy oil conversion processes. Three knowledge discovery database techniques—intercriteria and regression analyses, and artificial neural networks—were used to evaluate the performance of commercial FCC and EBVRHC in processing 19 different heavy oils. Seven diverse FCC catalysts were assessed using a cascade and parallel fresh catalyst addition system in an EBVRHC unit. It was found that the vacuum residue conversion in the EBVRHC depended on feed reactivity, which, calculated on the basis of pilot plant tests, varied by 16.4%; the content of vacuum residue (VR) in the mixed EBVRHC unit feed (each 10% fluctuation in VR content leads to an alteration in VR conversion of 1.6%); the reaction temperature (a 1 °C deviation in reaction temperature is associated with a 0.8% shift in VR conversion); and the liquid hourly space velocity (0.01 h-1 change of LHSV leads to 0.85% conversion alteration). The vacuum gas oil conversion in the FCC unit was determined to correlate with feed crackability, which, calculated on the basis of pilot plant tests, varied by 8.2%, and the catalyst ΔCoke (each 0.03% ΔCoke increase reduces FCC conversion by 1%), which was unveiled to depend on FCC feed density and equilibrium FCC micro-activity. The developed correlations can be used to optimize the performance of FCC and EBVRHC units by selecting the appropriate feed slate and catalyst.

Deactivation and regeneration dynamics in hierarchical zeolites: Coke characterization and impact on catalytic cracking of vacuum gas oil

This study investigated the deactivation and regeneration of hierarchical zeolites in vacuum gas oil conversion, aiming to reach the equilibrium state seen in fluidized bed catalytic cracking (FCC). The research utilized various characterization techniques to analyze the properties of zeolites before and after coking and regeneration. Zeolite Y-0.20-S was found to have the highest gasoline selectivity and quality, mirroring industrial yields, and displayed notable stability across deactivation/regeneration cycles. Higher mesopore concentration in zeolites led to increased coke selectivity and better resistance to deactivation. The study observed a dominance of aromatic coke with a higher degree of condensation in these zeolites. Despite coke deposition affecting acid and textural properties, the regeneration process effectively restored these characteristics, proving its efficiency. The zeolites with greater mesoporosity retained their fundamental properties responsible for activity and selectivity, highlighting the importance of selecting materials that provide high conversions and maintain stability and product selectivity over multiple cycles. The Y-0.20-S zeolite, in particular, was identified as a promising candidate for commercial catalyst development for gasoline production, contributing to the FCC process's energy efficiency.

Hierarchical Y Zeolite-Based Catalysts for VGO Cracking: Impact of Carbonaceous Species on Catalyst Acidity and Specific Surface Area.

The performance of catalysts prepared from hierarchical Y zeolites has been studied during the conversion of vacuum gas oil (VGO) into higher-value products. Two different catalysts have been studied: CatY.0.00 was obtained from the standard zeolite (Y-0.00-M: without alkaline treatment) and CatY.0.20 was prepared from the desilicated zeolite (Y-0-20-M: treated with 0.20 M NaOH). The cracking tests were carried out in a microactivity test (MAT) unit with a fixed-bed reactor at 550 °C in the 20-50 s reaction time range, with a catalyst mass of 3 g and a mass flow rate of VGO of 2.0 g/min. The products obtained were grouped according to their boiling point range in dry gas (DG), liquefied petroleum gas (LPG), naphtha, and coke. The results showed a greater conversion and selectivity to gasoline with the CatY.0.20 catalyst, along with improved quality (RON) of the C5-C12 cut. Conversely, the CatY.0.00 catalyst (obtained from the Y-0.00-M zeolite) showed greater selectivity to gases (DG and LPG), attributable to the electronic confinement effect within the microporous channels of the zeolite. The nature of coke has been studied using different analysis techniques and the impact on the catalysts by comparing the properties of the fresh and deactivated catalysts. The coke deposited on the catalyst surfaces was responsible for the loss of activity; however, the CatY.0.20 catalyst showed greater resistance to deactivation by coke, despite showing the highest selectivity. Given that the reaction occurs in the acid sites of the zeolite and not in the matrix, the increased degree of mesoporosity of the zeolite in the CatY.0.20 catalyst facilitated the outward diffusion of products from the zeolitic channels to the matrix, thereby preserving greater activity.

Maximizing High Value Light Products by Catalytic Cracking of VGO Produced by Iraqi Refinery over Formulated FCC Catalyst

Prototype of FCC catalyst were formulated by mixing the stabilised Y zeolites (68wt%) with polyvinal alcohol (PVA) (7%) as a solution binder and bentonite (25%). The Y zeolite including the original HY with Si/Al of 2.6 (cat.-2.6) and dealuminated HY with Si/Al of 30 (cat.-30) were used and tested for catalytic cracking of Iraqi vacuum gas oil (VGO) obtained from Al-Dura refinery using a pilot plant. The cracking process was carried out at a temperature of 520 °C and atmospheric pressure, The weight ratio of catalyst / oil ratio was 3 and 5. The results show that higher conversion of 77 wt. % and better product distribution (gasoline, kerosene and gas oil) could be obtained over cat.30 resulting to a good liquid product yield. The catalytic activity, in terms of VGO conversion was not affected over cat.-30 in spite of its lower acidity, suggesting the determinate of mesoporosity in the Y zeolite (cat.-30) catalysed cracking reactions. A higher yield of ~ 67 wt% to mid-distillates (i.e.Naphtha and kerosene) was as a result of the improvements in the diffusion to and from catalyst structure.

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.

The fabrication of Ce promoted Ni/Mg/Al mixed oxides hydrotalcite washcoated alloy, monolith catalyst for catalytic steam cracking of vacuum gas oil

Ce-promoted Ni/Mg/Al mixed oxides hydrotalcite-derived catalyst washcoated on metallic FeCrAlloy monolith was investigated in catalytic steam cracking of Vacuum Gas Oil (VGO) over a mild temperature range (300–400 °C). Hydrotalcite-derived powder solids were used as a slurry for the washcoating process were synthesized using co-precipitation and subsequent thermal decomposition. The as-fabricated catalyst exhibited over 40% VGO conversion with 46% light cut (Naphtha, Kerosene and Diesel) and 47.7% light VGO selectivity and Total Acidity Number of 0.9 mg KOH/g sample. This result seems promising for steam cracking of VGO over a novel structured catalyst. The washcoated catalyst was characterized using X-ray diffraction, surface area and X-ray Photoelectron Spectroscopy. Also, the liquid products composition/ quality and gas products composition were measured with various techniques such as simulation distillation, gas chromatography, viscosimeter and micro carbon residue.

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.

Effect of co-feeding HDPE on the product distribution in the hydrocracking of VGO

Abstract The hydrocracking of high-density polyethylene (HDPE) mixed with vacuum gasoil (VGO) (20 wt% HDPE) has been investigated with the aim of assessing this valorization strategy to obtain products suitable to be used as commercial fuel blending streams. The runs have been conducted in a batch reactor at: 400–440 °C; 80 bar; catalyst to feed ratio, 10 gcat gfeed−1; and reaction time, 2 h. Using three different catalysts, PtPd/Y, NiW/Y and NiMo/SA, the effect of the temperature and the composition of the products have been analyzed, comparing obtained results in the hydrocracking of VGO with those obtained for the HDPE/VGO blend. The products distribution has been quantified determining the yields of different lumps, defined according to their boiling point range: gas, naphtha, light cycle oil, heavy cycle oil and coke. The concentration of the families of compounds has been also determined: paraffins, olefins, naphthenes and aromatics (mono-, di- and poly-). Obtained results reveal that the addition of HDPE to the VGO is a promising way to valorize the HDPE, improving the conversion of VGO while producing interesting valuable products. Indeed, at 440 °C and with PtPd/Y catalyst total conversion of HDPE has been obtained, with a naphtha yield of 31.8 wt%.

Hydrocracking vacuum gas oil with wax

Abstract The hydrocracking of vacuum gas oil (VGO) and a mixture of 90 wt% VGO and 10 wt% wax was investigated. The study provided insight into processing of naturally waxy petroleum, as well as refinery co-processing of Fischer–Tropsch products with petroleum. The investigation was performed using flow reactor system at kilogram per day scale. Hydrocracking was investigated over a sulfided NiMo/SiO2-Al2O3 catalyst in the temperature range 330–410 °C at 9.5 MPa and LHSV of 1.3 h−1 with H2-to-feed ratio of 620 normal m3/m3. Atmospheric residue conversion of the VGO was 8–12% higher than conversion of VGO + wax at 330–380 °C, and 24% higher at 410 °C. Hydrodesulfurization conversion of the feed (3 wt% S) was less for VGO than for VGO + wax. Hydrodenitrogenation conversion of the feed (0.2 wt% N) was less for VGO than for VGO + wax. Directionally the observations could be explained in terms of competitive adsorption. However, the extent of the difference in atmospheric residue conversion was more than could be explained by competitive adsorption and VGO dilution by wax. It was postulated that changes in the bulk solubility characteristics of the liquid contributed to alter the relative concentration of species at the catalyst surface based on the change in the solubility parameter of the bulk liquid relative to the individual species. In this way it was possible to also account for the extent of the conversion difference observed during hydrocracking of VGO and VGO + wax at similar conditions.

Kinetics of the synergy effects in heavy oil upgrading using novel Ni-p-tert-butylcalix[4]arene as a dispersed catalyst with a supported catalyst

This study investigates the promotional effects of implementing a co-catalytic system for hydrocracking of vacuum gas oil (VGO) that includes both dispersed and supported solid catalysts. A novel nickel-based p-tert-butylcalix[4]arene (Ni-TBC[4]) was employed as a dispersed catalyst in addition to a commercial first-stage hydrocracking supported catalyst. Slurry-phase hydrocracking was conducted isothermally under a hydrogen pressure of 8.5 MPa in a batch autoclave reactor by varying the reaction temperature (390–450 °C) and duration (0.5–1.5 h). The use of the synthesized metallocalixarene as a dispersed catalyst precursor enhanced the hydrogenation activity and noticeably reduced the coke and gas formation. The yields of coke and gases decreased upon introducing the dispersed catalyst along with the supported solid catalyst by 35.86% and 13.90%, respectively. The yield of naphtha increased from 15.27 wt% to 16.36 wt%, and that of distillate increased from 52.17 wt% to 53.57 wt% compared with the use of the supported catalyst, while the conversion of VGO was unchanged at about 83.20%. The value of the dimensionless catalytic activity parameter proved the existence of the synergy between the two catalysts since it is much higher than that acquired through the algebraically calculated yields. A five-lump discrete kinetic scheme was developed based on the experimental data governed from both the standalone supported catalyst and the mixed catalysts. The model incorporated the conversion of VGO to distillate, naphtha, and C1–C5 gaseous hydrocarbons in addition to coke deposition. The activation energy of the distillate formation was reduced from 65.39 kcal/mol to 57.32 kcal/mol by adding a Ni-TBC[4] catalyst precursor in the presence of supported catalyst.

Synthesis and characterization of Zr incorporated small crystal size Y zeolite supported NiW catalysts for hydrocracking of vacuum gas oil

A series of Zr incorporated small crystal size Y zeolites were successfully synthesized by a direct hydrothermal method, and the corresponding NiW catalysts were prepared for the hydrocracking of vacuum gas oil (VGO). The synthesized zeolites and prepared catalysts were characterized by XRD, SEM, FTIR, Pyridine FTIR, H2-TPR and TEM techniques. The results show that the synthesized zeolites have uniform morphology and small crystal size, while Zr4+ incorporated into the framework of Y zeolite has been confirmed by XRD and FTIR. The amount of acid sites of xZrY zeolite slightly increases compared with that of Y zeolite by Pyridine FTIR. Moreover, the Zr4+ incorporation into Y zeolite can increase the W species reducibility, modulate the length and stacking of WS2 phase, and enhance the W species dispersion on the catalyst surface by H2-TPR and TEM, which favor to improve the hydrogenation activity of the catalyst to tune the balance between cracking activity and hydrogenation/dehydrogenation activity. Hence, the catalyst containing xZrY zeolite exhibits not only higher yield and selectivity of middle distillate but also slightly higher conversion of VGO compared with the catalyst containing Y zeolite.

The hydrothermal stability of the alkali-treated ZSM-5 and it’s catalytic performance in catalytic cracking of VGO

To enhance the heavy oil cracking ability of ZSM-5, desilication by alkali has been adopted in this study. The results showed that desilication by NaOH, NaOH/Al(NO3)3, NaOH/(NH4)3PO4 solutions all can induce some mesoporous structure to ZSM-5 zeolite. Among them, the sample ZSM-5/NaOH/(NH4)3PO4-F showed the highest mesoporous surface area. The hydrothermal stability of the desilicated ZSM-5 samples was also measured. The NaOH-modified ZSM-5 sample exhibited worse hydrothermal stability than the parent ZSM-5, while NaOH/(NH4)3PO4 modified ZSM-5 sample maintained the higher relative crystallinity and more acidic sites than the parent ZSM-5 after the hydrothermal treatment. The micro-activity tests showed that the NaOH/Al(NO3)3, NaOH/(NH4)3PO4-modified ZSM-5 samples exhibited higher catalytic activity than the parent ZSM-5 sample and NaOH-modified ZSM-5 sample in catalytic cracking of vacuum gas oil (VGO). Especially, for the sample ZSM-5/NaOH/(NH4)3PO4, the conversion of VGO increased from 78.91 to 85.13%, and the yield of propylene increased from 15.01 to 18.83% compared to the unmodified ZSM-5 catalyst.

Zeolite Y Mother Liquor Modified γ-Al2O3 with Enhanced Brönsted Acidity as Active Matrix to Improve the Performance of Fluid Catalytic Cracking Catalyst

A new matrix material for the fluid catalytic cracking (FCC) catalyst was prepared using the zeolite Y mother liquor to modify the surface acidity of γ-Al2O3. The modified γ-Al2O3 was characterized using a variety of techniques, and the relationship between surface acidity and catalytic performances in the catalytic cracking of vacuum gas oil (VGO) was correlated. Characterization results showed that Bronsted acid sites derived mainly from isolated silanol groups, which increased on modified γ-Al2O3, while Lewis acid sites reduced dramatically after modification. Correlation results indicated that increased Bronsted acid sites effectively improved the conversion of VGO. In addition, new medium strong acid sites engendered at the interfaces of γ-Al2O3/amorphous silica–alumina or γ-Al2O3/zeolite Y played a critical role in determining the final product distribution, leading to yields of gasoline and liquefied petroleum gas higher than those of the pure γ-Al2O3 derived catalyst.

Effect of baffles on performance of fluid catalytic cracking riser

Increasing demand of automobile fuel and a need to process heavier crude oil makes it imperative to find improvements to the design of existing fluid catalytic cracking (FCC) units. Several modifications to the design of the riser section of FCC units have been suggested in previous studies including: improved feed nozzle designs, multiple nozzle configurations, internal baffles, and novel two-stage-riser systems. In this study, we investigate the effects of baffles on the performance of FCC risers using computational fluid dynamics simulations. In this study, predictions from a basis model (without baffles) are compared with those from four different configurations including: (i) 5-cm baffles at 5-m spacing, (ii) 7.5-cm baffles at 5-m spacing, (iii) 10-cm baffles with 5-m spacing, (iv) 10-cm baffles at 2.5-m spacing, and (v) 10-cm baffles at 1-m spacing. The baffles force the catalyst away from walls toward the center of the riser, enhancing the radial dispersion of the catalyst and the heat transfer inside the riser. The use of longer baffles and smaller spacings further increases the dispersion, yielding more homogeneous radial profiles. The changes in the radial dispersion result in variations in the conversion, yields, and pressure drops. The baffles increase conversion of vacuum gas oil (VGO) and the yield of gasoline. However, the simulations showed that longer baffles and a larger number of baffles did not always give a higher yield or higher conversion. Among the simulated configurations, the 5-cm baffles at 5-m spacing gave the highest conversion of VGO, whereas the 10-cm baffles at 1-m spacing resulted in the highest yield of the gasoline. Thus, rational optimization of baffle configurations is required to achieve optimal performance.

Optimal design and operation of an industrial fluidized catalytic cracking reactor

Fluidized catalytic cracking (FCC) is regarded one of the most significant operations in the oil refining industries to convert feedstock (mainly vacuum gasoil) to valuable products (namely gasoline and diesel). The behavior of the fluidized catalytic cracking process is playing a main part on the overall benefits of refinery units and improving in process or control of fluidized catalytic cracking plants will result in exciting benefits economically. According to these highlights, this study is aimed to develop a new mathematical model for the FCC process taking into account the complex hydrodynamics of the reactor regenerator system with a new six lumps kinetic model for the riser. The mathematical model, simulation and optimization have done utilizing vacuum gas oil (VGO) as a feedstock and zeolite as a catalyst under the following operating conditions: temperature (733K, 783K, and 813K), weight hourly space velocity (5, 20 and 30h−1) and catalyst to oil ratio (4, 7 and 10). The best kinetic parameters of the relevant reactions are estimated using the optimization technique based on the experimental results taken from literature. The effect of operating condition (mainly, reaction temp (T), catalyst to oil ratio (CTO) and weight hourly space velocity (WHSV) on the product composition has also been discussed. The optimal kinetic parameters obtained from the pilot plant scale have been employed to develop an industrial FCC process, where optimal operating condition based on maximum conversion of VGO with minimum cost in addition to maximizing the octane number of gasoline (GLN), have been studied. Minimum coke content deposition the catalyst within the regenerator is also investigated here. New results (the highest conversion and octane number, and the lowest coke content) have obtained in comparison with those reported in the literature.

Kinetics of Promotional Effects of Oil-Soluble Dispersed Metal (Mo, Co, and Fe) Catalysts on Slurry Phase Hydrocracking of Vacuum Gas Oil

This study deals with the promotional effects of dispersed cocatalysts on hydrocracking of vacuum gas oil (VGO). The influence of oil-soluble molybdenum-, iron-, and cobalt-based materials is investigated with and without the presence of a commercial first-stage W–Ni/Al2O3–SiO2 hydrocracking catalyst. The experiments are conducted in a batch autoclave reactor (at 8.5 MPa and 420 °C). The dispersed metal catalysts enhanced the hydrogenation activity and reduced coke formation. Cobalt- and molybdenum-based cocatalysts show lower coke formation than the Fe cocatalyst. An addition of 500 ppm of Co or Mo cocatalyst decreased the amount of coke to 0.9 wt % from 2.5 wt % observed during the thermal cracking. The dispersed catalyst together with the supported catalyst shows similar decrease in coke formation and enhanced the yield of naphtha. A 5-lump kinetic model is developed based on the experimental data using dispersed and supported catalysts. The model incorporates coke formation and conversion of VGO to di...

Utilization of exhausted dust from FCC flue gas as material for FCC catalyst preparation

In this paper, new matrix and corresponding fluidized catalytic cracking (FCC) catalysts were prepared by reutilizing the exhausted dust which was derived from fluidized catalytic cracking flue gas. The results showed that the new matrix has wider mesopore size distribution than pseudo-boehmite binder. With the increase of the additional amount of this new matrix, FCC catalyst possessed increased micro-activity test conversion of vacuum gas oil (VGO) from 68 % to 71 %. The catalytic cracking performance on a fixed fluidized bed unit showed that compared with CAT-1, the conversion of VGO on CAT-5 increased by 1.19 %, heavy oil yield and coke yield decreased by 2.16 and 1.65 %, respectively. Besides, the total liquid yield and light oil yield increased by 2.27 and 2.26 %, respectively. The reaction performance of CAT-3 and CAT-5 is obviously superior to CAT-1. The appropriate pore structures and crystallized Y zeolite component on this new matrix improve the cracking ability of FCC catalysts.

Maximizing Diesel Production From Vacuum Gas Oil Using a Two Stage Hydrocracker

In this study, a six-lump model was sufficient to describe the kinetics of vacuum gas oil (VGO) hydrocracking in order to maximize the production of middle distillate diesel. The kinetic lump model target was to obtain the reaction rate constants that represent all the hydrocracking reactions in the process. The operating conditions such as temperature, pressure, and hydrogen severity were tested to find the optimum parameters that maximize diesel yields. Mild hydrocracking operating conditions of temperature and pressure were used in a commercial hydrocracker with hydrogen severity similar to hydrotreating processes. The main reaction was the VGO conversion to diesel based on its high reaction rate constant compared with other reactions. In addition, the main reaction had the highest effect on catalyst deactivation based on the resulted deactivation factor. A multi-linear regression correlation was obtained for maximizing diesel production as a function of operating pressure, temperature, and hydrogen amount, keeping the diesel specifications within the market demand.

Y/MCM-41 composites assembled from nanocrystals

Using commercial NaY zeolites as silica–alumina source, Y/MCM-41 composites were synthesized via self-assembly of nanocrystals. The formation of the composites is consistent with overgrowth of mesoporous MCM-41 on zeolite Y. The mesostructures with ordered core–shell and randomly orientated stacks can be shown when the NaY was treated with Na2SiO3 and NaOH solution, respectively. The hydrothermal stability of the sample with randomly orientated stacks is inferior to that of with core–shell structure. The composite with core–shell structure retains an ordered hexagonal structure upon hydrothermal treatment in pure steam environment as well as upon the replacement of Na+ by NH4+ ions in severe conditions. It has higher Si/Al ratio, more acid sites compared with the sample prepared in the presence of NaOH. The order of Al species in the composite prepared with Na2SiO3 solution is superior to that of in the composite obtained with NaOH solution. In addition, the fluid catalytic cracking (FCC) catalyst with Y/MCM-41 of core–shell structure exhibits the higher conversion of vacuum gas oil (VGO) and total liquid yield than catalysts with Y/MCM-41 with randomly orientated stacks and HY zeolite.