Hydrocracking Of Residue Research Articles

CFD coupled mixing cell network modelling of slurry-phase reactor for vacuum residue hydrocracking

The escalating global demand for light-end products, including low-sulfur diesel and gasoline, has prompted refineries to undergo strategic modernization efforts. This involves optimizing processes to efficiently handle heavy crude oil and transform it into high-value, user-friendly products. Slurry-phase hydrocracking is an advancing technology to enhance the production of these essential fuels, aligning with evolving market requirements and environmental regulations. The work encompasses crucial aspects such as potential hydrocracking reactions, lump kinetics, and product yield, all meticulously examined through the modelling and simulation of the Slurry-Phase Reactor (SPR). This study highlights the feasibility of integrating Computational Fluid Dynamics (CFD) simulation with Mixing Cell Network (MCN) modelling of SPR to account back-mixing effects with different lump reaction kinetics. CFD proves its importance for studying SPRs’ local hydrodynamics as compared to experimental investigation. Local level hydrodynamics of a lab-scale SPR were investigated and effectively utilized in MCN modelling. It encompasses the validation of product yield distribution derived from the developed MCN and Axial Dispersed Model (ADM) with experimental data and it also includes the comparison of hydrodynamic parameters reported in existing literature. An average absolute error of 3.85 % in the product yield was obtained between experiments and the developed MCN model. The residue conversion of 82.84% was achieved, followed by 29% of asphaltene, to explore insights into physicochemical properties characterized by product distribution. Further, the detailed product distribution and mass yield of each lump kinetic model was reported. Sensitivity analysis was conducted to investigate the impact of dispersion correlation on conversion initial bubble size on hydrodynamics and reaction conversion in the SPR.

Structural design and electronic regulation of atomically dispersed Mo-S4 sites by second shell N species reconfiguration for intensifying hydrogen spillover

Intensifying hydrogen spillover by regulating the atomic local structures catalysts is crucial for improving the hydrogenation performance, but still hugely challenging. Herein, we report a robust single-atom catalyst featuring Mo-S4 sites in the first shell modulated with N atoms in the second shell (Mo-S4-N/C) by an efficient cyclodextrin supramolecular self-assembly pyrolysis strategy for intensifying hydrogen spillover in slurry-phase hydrocracking of vacuum residue (VR). We discovered that the H2 is activated at the single-atom Mo-S4 sites efficiently and the spillover of active hydrogen is accelerated by the reconfiguration of N species in the second shell. Remarkably, the Mo-S4-N/C catalyst demonstrates excellent catalytic hydrogenation activity with high turnover frequency calculated for total metals up to 0.46 s−1, the VR per pass conversion of 61 wt.%, liquid product yield of 94 wt.%, and the low coke content of 0.6 wt.%, along with good stability, respectively. Theoretical calculations revealed that the N species in the second shell regulated the electronic structure of Mo-S4 sites, promoting the migration of active hydrogen species by reducing the transfer energy barrier of hydrogen spillover, thus enhancing the hydrogenation performance. This work proposed a strengthened hydrogen spillover mechanism from the atomic scale for hydrogenation reaction, offering novel concepts for designing and developing high-performance hydrogenation catalysts.

Effect of active site size in dispersed MoS2 nanocatalysts on slurry-phase hydrocracking of residue

This work investigates the influence of active site size in dispersed MoS2 on the slurry-phase hydrocracking of Merey residue (MRR). MoS2 nanocatalysts with varying morphologies were synthesized using the ligand sulfurization method, employing molybdenum oleate as the Mo precursor. The results demonstrate that mono-layered or double-layered MoS2 plates with slab sizes of 3 ∼ 10 nm can be synthesized at a sulfurization temperature of 400 °C and a sulfurization time of 0.5 h. Prolonged sulfurization time results in the growth and agglomeration of MoS2 plates, leading to multi-layered slabs with increased length and larger particle size, as well as a wider distribution range. The MoS2-0.5 (prepared with a sulfurization time of 0.5 h) exhibits superior hydrocracking activity, effectively converting resin and asphaltene into light fractions and significantly suppressing coke formation. Specifically, the conversion rates of resin and asphaltene are 51.3 wt% and 92.1 wt%, respectively, with the minimal coke yield of 0.6 wt% under conditions of 430 °C, 1 h, 7 MPa initial H2, and a catalyst dosage of 500 μg/g. The catalytic activity of the MoS2 nanocatalysts exhibits a strong correlation with their size and morphology obtained at different sulfurization times. Density functional theory (DFT) calculations reveal that MoS2 with smaller slab sizes are more beneficial for the adsorption and dissociation of H2, due to higher adsorption energy (Eads) and lower activation barrier (Ea). This facilitates the generation of sufficient active hydrogen to encourage the hydrocracking of residue and suppress coke formation.

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.

Molecular transformation of heavy oil during slurry phase hydrocracking process: influences of operational conditions

The influences of reaction temperature, duration, pressure, and catalyst concentration on the molecular transformation of residual slurry phase hydrocracking process were investigated. The molecular composition of the heteroatom compounds in the residue feedstock and its upgrading products were characterized using high-resolution Orbitrap mass spectrometry coupled with multiple ionization methods. The simultaneous promotion of cracking and hydrogenation reactions was observed with increasing of the reaction temperature and time. Specifically, there was a significant increase in the cracking degree of alkyl side chain, while the removal of low-condensation sulfur compounds such as sulfides and benzothiophenes was enhanced. In particular, the cracking reactions were more significantly facilitated by high temperatures, while an appropriately extended reaction time can result in the complete elimination of the aforementioned sulfur compounds with a lower degree of condensation. Under conditions of low hydrogen pressure and catalyst concentration, the products still exhibit a high relative abundance of easily convertible compounds such as sulfoxides, indicating a significant deficiency in the effectiveness of hydrogenation. The hydrogen pressure exhibits an optimal value, beyond which further increments have no effect on the composition and performance of the liquid product but can increase the yield of the liquid product. At significantly high catalyst concentration, the effect of desulfurization and deoxidation slightly diminishes, while the aromatic saturation of highly condensed compounds was notably enhanced. This hydrogenation saturation effect cannot be attained through manipulation of other operational parameters, thereby potentially benefiting subsequent product processing and utilization. This present study demonstrates a profound comprehension of the molecular-level residue slurry phase hydrocracking process, offering not only specific guide for process design and optimization but also valuable fundamental data for constructing reaction models at the molecular level.

Preparation of presulfided oil-soluble NiMo catalyst for slurry bed hydrocracking of vacuum residue

Here, a method is proposed for constructing presulfided oil-soluble NiMo catalysts using tetrathiomolybdate nickel ammonium as a precursor via a chelating ligand exchange strategy. Leveraging the close chemical bonding between Ni and Mo atoms, the NiMo catalyst can undergo in-situ self-sulfidation to generate active NiMoS sites and a composite structure of Ni3S2 and MoS2 nano phase in tight contact, thus exhibiting strong synergistic effects. The NiMo catalyst exhibited outstanding performance in hydrocracking of vacuum residue (VR) achieving a 64.7 wt% VR conversion while maintaining a coke yield of 0.51 wt%, as well as the excellent hydrogenation activity of polycyclic aromatic hydrocarbons. Combined with density functional theory calculations, it was further revealed that the presence of Ni reduces the energy barrier for H2 dissociation on MoS2, thereby enhancing the hydrogenation activity of the catalyst and its ability to suppress coke formation. This work validates the efficient bimetallic synergistic catalytic effect of presulfided oil-soluble NiMo catalysts in the slurry bed hydrocracking process.

Industrial Investigation of the Combined Action of Vacuum Residue Hydrocracking and Vacuum Gas Oil Catalytic Cracking While Processing Different Feeds and Operating under Distinct Conditions

Ebullated bed vacuum residue hydrocracking and fluid catalytic cracking (FCC) are among the most profitable processes in modern refining. Their optimal performance is vital for petroleum refining profitability. That is why a better understanding of their combined action and the interrelations between these two heavy oil conversion processes in a real-world refinery could provide valuable information for further performance optimization. Nine distinct petroleum crudes belonging to the extra light, light, and medium petroleum crude types were processed in the LUKOIL Neftohim Burgas refinery to study the combined performance of two processes: FCC of vacuum gas oil and ebullated bed vacuum residue H-Oil hydrocracking. The operating conditions along with the characterization data of the feeds and products of both processes were evaluated through the employment of intercriteria analysis to define the variables with statistically significant relationships. Maple 2023 Academic Edition mathematics software was used to develop models to predict the vacuum residue conversion level under different operating conditions. The plug flow reactor model with an activation energy of 215 kJ/mol and a reaction order of 1.59 was found to provide the highest accuracy of vacuum residue conversion, with an average absolute deviation of 2.2%. H-Oil yields were found to correlate with the vacuum residue conversion level and the content of FCC slurry oil (SLO), the recycling of partially blended fuel oil, a material boiling point below 360 °C, and the vacuum gas oil (VGO) in the H-Oil feed. FCC conversion was found to depend on the H-Oil VGO content in the FCC feed and the content of FCC SLO in the H-Oil feed.

Hydrocracking of heavy oil residues with the participation of Ni-bentonite

In the article, Ni-bentonite catalyst was synthesized by exchange method. Natural bentonite mineral and synthesized catalyst were studied by XRD, XRF, TGA/TDA, TEM, EDX-mapping (map), nitrogen adsorption-desorption at 196 °C, H2-TPD and NH3-TPD analysis methods. A new processing technology was introduced at the «Hydrocracking of heavy oil residues» (SPR-1) facility with the participation of fuel oil bentonite and Ni-bentonite catalysts. The catalytic efficiency of dispersed nickel catalyst in the hydrocracking process of fuel oil under optimal conditions (430 °C, 4.0 MPa) was studied. The results of the experiments are 47% from catalyst-free hydrocracking of fuel oil; 54.7% with bentonite addition; The yield of light colored petroleum products showed a corresponding increase to 67.1% when Ni-bentonite was used. Keywords: fuel oil; hydrocracking; bentonite; gasoline fraction; diesel fraction.

Comparative study of single- and two-stage slurry-phase catalytic hydrocracking of vacuum residue for selective conversion of heavy oil

The selective conversion of asphaltenes to light products while inhibiting coke formation is the most challenging in the heavy oil upgrading process. Herein, single- and two-stage slurry-phase catalytic hydrocracking of vacuum residue (VR) at various reaction temperatures (350–430 °C) were performed to elucidate the advantages of low temperature conditions and the synergistic effect of two-stage operation on asphaltene conversion. Despite the slow reaction rate at a low reaction temperature, almost no coke was produced, and the selective conversion of asphaltene to deasphalted oil (DAO) was improved with a large amount of H2 consumption. To overcome the low reaction rates at low temperatures, catalytic hydrocracking was performed at two-stage temperatures (380 and 430 °C). Two-stage catalytic hydrocracking showed a synergistic effect of suppressing coke formation while maintaining an enhanced reaction rate compared to single-stage catalytic hydrocracking. This is because the first stage of hydrocracking at 380 °C facilitates the saturation of heavy polyaromatic molecules, which can easily crack in the second stage at 430 °C. However, because two-stage hydrocracking requires a slightly longer reaction time than single-stage hydrocracking to achieve the same conversion, the efficiency of asphaltene conversion must be considered by setting appropriate operating conditions.

The effect of recycle stream on slurry-phase hydrocracking of vacuum residue: An experimental and modeling approach

The effect of the recycle stream on slurry-phase hydrocracking (HCK) of vacuum residue was examined using a continuous bench-scale unit with the aim of attaining process optimization. This was achieved through a model-based approach that links experimental investigations, kinetic modeling, and model-based optimization. The experiments were conducted at various reaction temperatures, liquid hourly space velocity of fresh feed (LHSVFF) and recycle ratios at a pressure of 160 bar, with the fresh feed containing 1000 wt. ppm of molybdenum. The HCK kinetic model was modified to incorporate the recycling effects and accurately predict the experimental data. The adapted model confirmed that the unconverted residue in recycle operating mode (ROM) became more refractory. By implementing the modified kinetic model in a dynamic Simulink model, the prediction accuracy of RES conversions and product yields can be improved by up to 25.1 wt.% in the case of the lowest conversion. A sensitivity analysis using the dynamic model showed that the temperature exerted a greater impact on the RES conversion and recycle ratio in ROM. An operational stability index was also proposed to prevent operation failure in ROM. Finally, an optimal operating condition from the parametric study was found to meet several process goals simultaneously.

The Effect of Carbon Nanofibers on the Hydrocracking of Vacuum Residue in the Presence of Formic Acid

This study was devoted to the processing of vacuum residue to produce lighter oil fractions, such as gasoline and diesel fuel. The hydrocracking and catalytic hydrocracking of vacuum residue in the presence of formic acid (FA) were performed in the temperature range of 250–550 °C. Carbon nanofibers (CNFs) were used as catalytic additives. In contrast to conventional hydrocracking, an important stage in the catalytic hydrocracking of vacuum residue is the decomposition of formic acid. Experimental studies on the effect of CNFs on the decomposition of FA demonstrated that CNFs pre-treated in a NaOH solution (CNF (NaOH)s) had the highest activity and selectivity for the production of H2 and CO2. The maximum yield of liquid products in the catalytic hydrocracking process, equal to 34 wt.%, was observed at 300 °C in the presence of CNF (NaOH)s. The characterization of the fractional compositions of the liquid products showed that the ratios of the fractions changed with an increase in the reaction temperature. The maximum concentrations of the light fractions (gasoline and diesel) in the liquid products of the catalytic hydrocracking of vacuum residue were observed at 300–350 °C in the presence of CNF (NaOH)s.

Nickel Sulfide/Hierarchical Porous Carbon from Spent Residue Hydrocracking Catalyst as Electrocatalyst for the Oxygen Evolution Reaction.

Spent residue slurry-phase hydrocracking catalyst coated with coke have been classified as hazardous solid waste, presenting serious economic and environmental issues to refiners. Herein, the spent catalysts with a nickel sulfide nanoparticle/coke hierarchical structure (NiSX /C) from our previous work were used to prepare nickel sulfide/hierarchical porous carbon (NiSX /HPC) for the oxygen evolution reaction (OER) through the method of carbonization, activation, and sulfurization. The results indicate that the NiSX /C converts into Ni/HPC after carbonization and activation, and then transform into NiSX /HPC by sulfurization. The optimized NiSX /HPC-8 possesses the crystal phase of NiS2 , and the high specific surface area of 1134.9 m2 g-1 with the hierarchical micro-mesoporous structure. Besides, NiSX /HPC-8 achieves a low overpotential of 236 mV at 10 mA cm-2 , a low Tafel slope of 64.1 mV dec-1 , and excellent stability. This work provides a viable method for upcycling spent catalysts to re-constructed OER catalysts with high catalytic performance and durability.

Modelling of a vacuum residue hydrocracking in an industrial slurry phase reactor

AbstractThe upgradation of the bottom of the barrel has gained much interest across the refineries due to severe environmental rules, limitations of conventional oil reserves, and its flexibility to produce light end products which benefit end users. Slurry phase hydrocracking is one of the growing technologies to fulfil the increasing demand for light cut. Modelling of an industrial slurry phase reactor (SPR) for vacuum residue hydrocracking using different kinetic models is proposed. The axial dispersion model (ADM) is used for modelling an industrial SPR. The mathematical model of the reactors is incorporated for the three different lump kinetic models. This study deals with the continuous stirred tank reactor (CSTR) and SPR modelling, followed by industrial SPR modelling. The small lab‐scale reactor models are validated with the experimental data reported in the literature. The study's objective was to investigate the one‐dimensional and two‐dimensional concentration dynamics of each lump along the axial and radial positions of industrial SPR. The vacuum residue conversion into the light fractions was obtained by more than 73% in industrial SPR. Also, the yield of vacuum gas oil and resins were evaluated as 49% and 63%, respectively. The sensitivity analysis was performed to explain the effect of process variables. The optimum range was found as a length of 15 m, liquid hourly space velocity (LHSV) of 0.2 h−1, 1% catalyst concentration, and 420°C reaction temperature to enhance the throughput of the reactor.

SAR-AD Method to Characterize Eight SARA Fractions in Various Vacuum Residues and Follow Their Transformations Occurring during Hydrocracking and Pyrolysis

Model compounds were used to provide some chemical boundaries for the eight-fraction SAR-ADTM characterization method for heavy oils. It was found that the Saturates fraction consists of linear and highly cyclic alkanes; the Aro-1 fraction consists of molecules with a single aromatic ring; the Aro-2 fraction consists of mostly 2 and 3-ring fused aromatic molecules, the pericondensed 4-ring molecule pyrene, and molecules with 3–5 rings that are not fused; and the Aro-3 fraction consists of 4-membered linear and catacondensed aromatics, larger pericondensed aromatics, and large polycyclic aromatic hydrocarbons. The Resins fraction consists of mostly fused aromatic ring systems containing polar functional groups and metallated polar vanadium oxide porphyrin compounds, and the Asphaltene fraction consists of both island- and archipelago-type structures with a broad range of molecular weight variation, aromaticity, and heteroatom contents. The behavior of the eight SAR-ADTM fractions during hydrocracking and pyrolysis was investigated, and quantitative relations were established. Intercriteria analysis and evaluation of SAR-ADTM data of hydrocracked vacuum residue and sediment formation rate in commercial ebullated bed vacuum residue hydrocracking were performed. It showed that total asphaltene content, toluene-soluble asphaltenes, and colloidal instability index contribute to sediment formation, while Resins and Cyclohexane-soluble asphaltenes had no statistically meaningful relation to sediment formation for the studied range of operation conditions.

Commercial Ebullated Bed Vacuum Residue Hydrocracking Performance Improvement during Processing Difficult Feeds

The Urals and Siberian vacuum residues are considered difficult to process in the ebullated bed hydrocracking because of their increased tendency to form sediments. Their achievable conversion rate reported in the literature is 60%. Intercriteria analysis was used to assess data from a commercial vacuum residue hydrocracker during processing blends from three vacuum residues: Urals, Siberian Light, and Basra Heavy. The analysis revealed that the main contributors to conversion enhancement is hydrodemetallization (HDM) and the first reactor ΔT augmentation. The increase of HDM from 40 to 98% and the first reactor ΔT (ΔT(R1)) from 49 to 91 °C were associated with a vacuum residue conversion enhancement of 62.0 to 82.7 wt.%. The developed nonlinear regression prediction of conversion from HDM and ΔT(R1) suggests a bigger influence of ΔT(R1) enhancement on conversion augmentation than the HDM increase. The intercriteria analysis evaluation revealed that the higher first reactor ΔT suppresses the sediment formation rate to a greater extent than the higher HDM. During processing Basrah Heavy vacuum residue, a reduction in hydrodeasphaltization (HDAs) from 73.6 to 55.2% and HDM from 88 to 81% was observed. It was confirmed that HDM and HDAs are interrelated. It was found that the attainment of conversion of 80 wt.% and higher during processing Urals and Siberian Light vacuum residues is possible when the HDM is about 90% and LHSV ≤ 0.19 h−1.

Highly active and stable CoWS2 catalysts in slurry phase hydrocracking of vacuum residue: XAFS studies

The bimetallic CoWS2 catalysts were prepared in situ during the slurry phase hydrocracking (HCK) of vacuum residue (VR) using W(CO)6 and Co-octoate as oil soluble precursors to investigate the promotional effect of Co promoters on the dispersed WS2 catalyst for the VR HCK. The morphologies and structural properties of dispersed catalysts were characterized by transmission electron microscopy (TEM) and X-ray absorption spectroscopy (XAS). The bimetallic CoWS2 catalyst was observed to form well-dispersed monolayers in the size range of 7–11 nm, which showed higher turn-over frequency values (TOF) and C7-asphaltene (C7-ASP) conversions than monometallic WS2 or Co9S8 catalysts in the VR HCK at 693 K and 10.0 MPa H2. Moreover, the extended X-ray fine absorption structure spectroscopy (EXAFS) coupled with the density functional theory (DFT) calculations successfully verified the formation of the Co-W-S phase.

Effect of Hydrocracking of Oil Distillation Heavey Residues on Production Efficiency of TAIF-NK JSC

Effect of Hydrocracking of Oil Distillation Heavey Residues on Production Efficiency of TAIF-NK JSC

Application of Ebullated-Bed Vacuum Residue Hydrocracking at Lukoil Neftohim Burgas

Application of Ebullated-Bed Vacuum Residue Hydrocracking at Lukoil Neftohim Burgas

Impacts of support properties on the vacuum residue slurry-phase hydrocracking performance of Mo catalysts

To deeply understand the effects of support properties on the performance of Mo-based slurry-phase hydrocracking catalysts, four Mo-based catalysts supported on amorphous silica alumina (ASA), γ-Al2O3, ultra-stable Y (USY) zeolite and SiO2 were prepared by the incipient wetness impregnation method, respectively, and their catalytic performances were compared in the vacuum residue (VR) hydrocracking process. It is found that the Mo/ASA catalyst exhibits the highest VR conversion among the different catalysts, indicating that both the appropriate amount of acid sites, especially B acid sites and larger mesoporous volume of ASA can enhance the VR hydrocracking into light distillates. Furthermore, Mo catalysts supported on the different supports show quite different product distributions in VR hydrocracking. The Mo/ASA catalyst provides higher yields of naphtha and middle distillates and lower yields of gas and coke compared with other catalysts, it is attributed to the highest MoS2 slab dispersion, the highest sulfuration degree of Mo species, and the most Mo atoms located at the edge sites for the Mo/ASA catalyst, as observed by HRTEM and XPS analyses. These features of Mo/ASA are beneficial for the hydrogenation of intermediate products and polycyclic aromatic hydrocarbons to restrict the gas and coke formation.

Опыт производства битумной продукции из остаточных продуктов комбинированной установки гидрокрекинга гудрона АО «ТАИФ-НК»

The article is devoted to the use of residual products of combined thermal and hydrocracking of vacuum residue and vacuum gasoil into demanded marketable petroleum products - into bitumen products in accordance with Russianand international quality standards.