Atmospheric Gas Oil Research Articles

Hierarchical ZSM-5@SiO2 Catalysts: A Novel Approach to Optimizing Olefin Yield from Heavy Atmospheric Gas Oil

Hierarchical ZSM-5@SiO₂ Catalysts: A Novel Approach to Optimizing Olefin Yield from Heavy Atmospheric Gas Oil

Co-processing of BTL Fischer-Tropsch wax and heavy vacuum gas oil

Co-hydrocracking of Fischer-Tropsch wax (FTW) derived from forest residue and petroleum-derived heavy vacuum gas oil (HVGO) is one of the potential ways to implement synthetic fuels into the transportation sector. Neat HVGO and its blends with FTW in mass ratios of 90:10, 70:30 and 50:50 were processed in the lab-scale continuous-flow catalytic unit with a fixed-bed reactor at reaction temperatures of 390 °C, 400 °C and 410 °C and pressure of 16 MPa over commercial hydrotreating and hydrocracking catalysts. The primary liquid products were fractionated using atmospheric and vacuum distillation in order to get fraction of naphtha (up to 150 °C), kerosene (150–230 °C), atmospheric gas oil (230–360 °C) and bottom residue (above 360 °C). The aim of the study was to evaluate the influence of the reaction temperature and FTW content in the feedstock on the yield and quality of the obtained products and potential of their utilization in the transportation sector. The highest conversion to the desired fuel fractions was observed at the highest reaction temperature and using the highest concentration of the FTW in the feedstock. The fractions can be utilized as high-quality fuel blending components or as a valuable feedstock in the petrochemical industry.

A molecular insight into coke formation process of vacuum residue in thermal cracking reaction

Understanding the coking behaviors has been considered to be really essential for developing better vacuum residue processing technologies. A battery of thermal cracking tests of typical vacuum residue at 410 °C with various reaction time were performed to evaluate the coke formation process. The total yields of ideal components including naphtha, atmospheric gas oil (AGO) and vacuum gas oil (VGO) of thermal cracking reactions increased from 10.89% to 40.81%, and the conversion ratios increased from 8.05% to 43.33% with increasing the reaction time from 10 to 70 min. The asphaltene content increased from 12.14% to a maximum of 22.39% and then decreased, and this maximum of asphaltene content occurred at the end of the coking induction period. The asphaltenes during the coking induction period, at the end and after coking induction period of those tested thermal cracking reactions were characterized to disclose the structure changing rules for coke formation process, and the coke formation pathways were discussed to reveal the coke formation process at molecular level.

Thermodynamic Modeling and Process Simulation of Kumkol Crude Oil Refining

The Crude Distillation Unit (CDU) mechanism is commonly regarded as the first stage in petroleum refining. In this study, Aspen Plus® is used to simulate the basic process of a CDU, which consists of an Atmospheric Distillation Column (ATC) and a Vacuum Distillation Column (VC). These columns are fed with two types of crude oil: KUMKOL from Kazakhstan and Soviet Export Blend, in the proportions of 0.75:0.25, 0.50:0.50, and 0.25:0.75, respectively. The goal was to do a parametric analysis and analyze the resultant streams of naphtha, kerosene, Atmospheric Gas Oil (AGO), Light Vacuum Gas Oil (LVGO), and Heavy Vacuum Gas Oil (HVGO). The simulation used the CHAO-SEA thermodynamic model, which included the Chao-Seader correlation, the Scatchard-Hildebrand model, the Redlich-Kwong equation of state, the Lee-Kesler equation of state, and the API gravity technique. Temperature, pressure, mass flow, enthalpy, vapor percentage, and average molecular weights of the streams at various phases within the CDU system were estimated. For both the ATC and VC columns, curves indicating Temperature- Pressure vs the number of stages, as well as ASTM D86 (temperature) versus stream volume % distillation, were developed. The results show that when compared to feed streams containing 0.25 and 0.50 StdVol of Kumkol Kazakhstan Oil, the feed stream with 0.75 StdVol produces more Heavy, Medium, and Light Vacuum Gas Oil (H-VGO, M-VGO, and L-VGO), as well as more Vacuum Gas (VG). These findings indicate that Kumkol Kazakhstan Oil is of high quality and has fewer contaminants, such as sulfur when compared to other accessible mixes throughout the world.

Effectiveness of Mo, NiMo, and CoMo catalysts for co-hydroprocessing furfural-acetone aldol condensation adducts with atmospheric gas oil to produce biofuels

Nowadays, supported sulfide transition-metal-based catalysts (Mo, CoMo and NiMo) are the most used hydrotreating catalysts. However, hydrotreating oxygen compounds derived from biomass means a challenge due to their deactivation by sulfur leaching. The co-processing approach could be a compromise solution, as it was for the hydrotreating of other oxygen compounds, such as triglycerides. The present work reports the use of four types of commercial sulfide catalysts (Mo/Al2O3, NiMo/Al2O3, CoMo/Al2O3 and CoMo/TiO2) for the co-processing of furfural-acetone aldol condensation adducts (FAA: 5–10 wt%) with atmospheric gas oil and isopropanol as co-solvent. The experimental tests were carried out in a fixed bed reactor at industrial operating conditions (T = 320 °C, WHSV = 0.5 h−1, P = 5.5 MPa). The conversion of FAA to alkanes did not significantly affect catalyst hydrodesulfurization and hydrodenitrogenation effectiveness (<1.0%). Moreover, C8 and C13 alkanes from FAA co-processing decreased hydrotreated gas oil density. Overall, our results point to the suitability of commercial sulfide hydrotreating catalysts for upgrading biomass-derived compounds to decarbonize current fuels using the existing refinery units.

Catalytic cracking of heavy atmospheric gas oil to light olefins over ZSM-5 zeolite: Effect of crystal size in the absence/presence of steam

The catalytic cracking of heavy atmospheric gas oil (AGO) has been investigated to study the effect of ZSM-5 zeolite crystal size on the selectivity to light olefin in the absence and presence of steam. Dodecane (used as model compound) and heavy AGO feed streams were utilized to study the influence of changing pore shape selectivity when comparing cracking performance by nano and micro ZSM-5 zeolites. The zeolites were characterized using BET, XRD NMR, NH3-TPD and Py-FTIR. In the presence of steam, the short pores length nano ZSM-5 crystals showed enhanced catalytic cracking activity and selectivity to light olefins. The nano ZSM-5 catalyst promoted higher selectivity to light olefins through β-scission while reducing the extent of hydrogenation reactions towards the formation of liquefied petroleum gas components (LPG). In contrast, the long pores length of micro ZSM-5 tended to favor the production of more naphtha, kerosene and LPG through hydrogen transfer routes, resulting in lower selectivity to light olefins. The resulting propylene/ethylene (P/E) ratios were altered by the type of feed used, cracking reaction temperature, influence of steam and catalyst crystal size. Specifically, higher P/E ratio was achieved over nano ZSM-5 zeolite, especially with the cracking of heavy AGO feed in the presence of steam, due to an increase of monomolecular reactions through β-scission cracking mechanism.

Synthesis of sulfur-free Co-Mo nitride catalysts for the hydrotreating of atmospheric gasoil and co-processing of rapeseed oil

Sulfur-free transition metal carbide and nitride catalysts have been shown to be reasonable substitutes for sulfidic catalysts for the hydrotreating middle distillates and vegetable oils. However, their catalyst activity is still lower than commercial catalysts. In this paper, we build on our previous research by studying the synthesis and testing of nine sulfur-free Al2O3-supported Co-Mo nitride catalysts for the hydrotreating of atmospheric gasoil and its blends with rapeseed oil (25 wt.%) under industrial conditions (330–350 °C, 5.5 MPa, WHSV 1–2 h−1). Nitration temperatures play the most significant role in the synthesis and activity of the catalyst, obtaining a CoMoNx catalyst whose catalytic behaviour competes with the current commercial sulfidic Ni-Mo or Co-Mo catalysts (reduction of sulfur and nitrogen content up to 99.0 and 84.0%, respectively). Thus, our results allow us to evaluate and define the most suitable synthesis conditions for preparing high activity sulfur-free Al2O3-supported Co-Mo nitride catalysts.

Catalytic hydroprocessing of camelina oil/AGO mixtures over NiMoP/γ-Al2O3 catalysts

Inedible camelina oil (CSO) contains fatty acids with a high degree of unsaturation (1.8 double bonds per fatty acid on average). CSO was hydrotreated at temperatures 340–370 °C, pressures of 15–50 bar, and liquid hour space velocities (LHSVs) of 0.8–1.1 h-1 for the production of hydrocarbons that are usable as diesel components. First, hydrotreating pure CSO at 340–370 oC and low hydrogen pressures of 15–25 bar led to the formation of a mixture of n-/iso- alkanes, aromatics, and higher olefins. The presence of CC double bonds in the CSO molecule affected the progress of the side reactions and caused rapid deactivation and coking of the catalyst, especially at low hydrogen partial pressure. Hydrotreatment co-processing of polyunsaturated CSO and partially hydrogenated CSO was then done with two different gas oils or two paraffinic solvents in the range of concentration 5–20%. Co-hydrotreatment took place in a bench-scale trickle-bed reactor using commercial NiMoP/γ-Al2O3 catalysts (catalysts A and B) and a prepared catalyst, NiMoCuP/ZrO2-γ-Al2O3 (catalyst C). High triacylglyceride conversion to hydrocarbons was achieved when CSO was hydrogenated in a mixture with paraffinic solvents on NiMoP/γ-Al2O3 catalysts at hydrogen partial pressures above 30 bar and temperatures above 350 oC. CSO decarboxylation/decarbonylation reactions prevailed over hydrodeoxygenation. Hydrodeoxygenation (72%) was predominant for catalyst C with significant methanation of CO and CO2. There was a complete TAG conversion into hydrocarbons when co-processing a mixture of CSO and atmospheric gas oil at a temperature of 360 oC, LHSV of 0.8 h-1, a hydrogen pressure of 50 bar, and various ratios of hydrogen to raw material from 312 to 656 NL.L-1. The deoxygenation activity decreased in the order of catalysts C>B>A. Increasing the ratio of H2 to feed had a positive effect on the composition and properties of the liquid product. During experiments with catalyst C at 50 bar, 370 °C, and ratios of hydrogen to raw material of 293–656 NL.L-1, the cetane index increased from 46 to 58, and the polyaromatic content decreased from 12.5 to 4.4 wt%. The sulphur and nitrogen contents of the product (29.5 mg.kg-1 and 13.2 mg.kg-1) were higher than expected. In the case of catalyst C, the degree of desulphurization was lower than that of catalysts A and B.

Pyrolysis Oils from Used Tires and Plastic Waste: A Comparison of a Co-Processing with Atmospheric Gas Oil

This study aimed to determine the effect of the supplied pyrolysis oils (oils obtained from the pyrolysis of used tyres and the depolymerisation of plastics) on the activity of the hydrodesulphurisation catalyst. Each pyrolysis oil was added at 20% weight to a standard feedstock and processed on pilot plant reactors under the set conditions of a commercial unit, including an activated catalyst. Following the catalyst stabilisation, the standard material was changed to the mixture with the pyrolysis oils. The reaction conditions, particularly the reaction temperature, were controlled. The results of the product analyses were compared with the EN 590 standard for evaluating diesel fuel; the hydrogenated mixed fuel meets most requirements. Only the density, flash point, distillation curve and lubricity have minor deviations, which could be adjusted by treating the sample before or after hydrogenation. The properties of the products, in terms of the low-temperature properties, were also investigated. The tyre-derived pyrolysis oils showed improved low-temperature properties, possibly due to the higher levels of the aromatic hydrocarbons. The pyrolysis oil obtained from the depolymerisation of the plastics was found to be more suitable for use in refineries without substantially impacting the existing technologies. For the tyre-derived pyrolysis oils, higher reaction temperatures were required for processing, which could affect the catalyst operation.

Co-processing of Atmospheric Gas Oil with Rapeseed Oil Over Sulfur-Free Supported and Phosphorus-Modified Co-Mo and Ni-Mo Carbide Catalysts

Co-processing of Atmospheric Gas Oil with Rapeseed Oil Over Sulfur-Free Supported and Phosphorus-Modified Co-Mo and Ni-Mo Carbide Catalysts

Phonolite Material as Catalyst Support for the Hydrotreatment of Gas Oil and Vegetable Oil Type Feedstocks.

Phonolite material has shown to be promising catalyst support for the deoxygenation of triglycerides. In this work, we continue with our previous research by synthesising and testing three acid-treated phonolite-supported Co-Mo, Ni-Mo and Ni-W catalysts for the hydrotreating of atmospheric gas oil and co-processing with rapeseed oil at industrial operating conditions (350–370 °C, WHSV 1–2 h−1, 5.5 MPa) in the continuous regime for more than 270 h. The phonolite-supported catalysts showed hydrotreating activity comparable with commercial catalysts, together with a complete conversion of triglycerides into n-alkanes. During co-processing, the Ni-promoted catalyst showed strong stability, with similar activity previous to the rapeseed oil addition. Our results enable us to evaluate the suitability of phonolite as catalyst support for the development of plausible alternatives to conventional hydrotreating catalysts for the co-processing of middle distillates with vegetable oils.

Experimental Evaluation of Hydrotreated Vegetable Oils as Novel Feedstocks for Steam-Cracking Process

Hydrotreated vegetable oils (HVOs) are currently a popular renewable energy source, frequently blended into a Diesel-fuel. In the paper, HVO potential as feedstock for the steam-cracking process was investigated, since HVOs promise high yields of monomers for producing green polymers and other chemicals. Prepared HVO samples of different oil sources were studied experimentally, using pyrolysis gas chromatography to estimate their product yields in the steam-cracking process and compare them to traditional feedstocks. At 800 °C, HVOs provided significantly elevated ethylene yield, higher yield of propylene and C4 olefins, and lower oil yield than both atmospheric gas oil and hydrocracked vacuum distillate used as reference traditional feedstocks. The HVO preparation process was found to influence the distribution of steam-cracking products more than the vegetable oil used for the HVO preparation. Furthermore, pyrolysis of HVO/traditional feedstock blends was performed at different blending ratios. It provided information about the product yield dependence on blending ratio for future process design considerations. It revealed that some product yields exhibit non-linear dependence on the blending ratio, and therefore, their yields cannot be predicted by the simple principle of additivity.

Impact of hydrogenation on miscibility of fast pyrolysis bio-oil with refinery fractions towards bio-oil refinery integration

In particular, a straw-based Ablative Fast Pyrolysis (AFP) oil was upgraded via hydrotreatment (HDT) in order to be used as a blending component with fossil-based intermediates. The raw pyrolysis oil is characterized by H/C = 0.14, O/C = 0.58 and C = 57.73 wt%, while the HDT pyrolysis oil has a H/C = 0.14, O/C = 0.016 and C = 85.85 wt%. Based on the density, viscosity and composition, and in association with a typical refinery, the possible petroleum refinery entry points for HDT pyrolysis oil include Straight Run Gas-Oil (SRGO), Atmospheric Gas-oil (GO), Fluid Catalytic Cracking Light Cycle Oil (LCO) and Heavy Cycle Oil (HCO), as well as Light Vacuum Gas-Oil (LVGO). To that aim, this work examined raw and HDT bio-oil blends with the aforementioned candidate petroleum streams at a 30:70 v/v ratio (raw or HDT bio-oil/petroleum stream) with respect to their miscibility, by comparing the blend components’ properties, microscopic observation, and interfacial tension analysis. From the microscopic observation, the addition of HDT pyrolysis oil in all examined petroleum candidates renders a homogeneous mixture where the two phases cannot be distinguished. In addition, no interfacial tension was observed in the examined blends, while the blend of HDT pyrolysis oil with the different petroleum streams not only did not deteriorate the fuel characteristics over the original petroleum stream, but also it improved them, in some cases. In general, the HDT pyrolysis oil was found to be miscible with all the examined refinery streams, extending the potential further investigation of stabilized pyrolysis oil integration over oil refineries.

Hydrotreating of Atmospheric Gas Oil and Co-Processing with Rapeseed Oil Using Sulfur-Free PMoCx/Al2O3 Catalysts.

Sulfur-free molybdenum carbides have the potential to replace the conventional sulfided catalysts used for hydrotreating. For these catalysts, it is not necessary to add sulfur to maintain their activity. This fact makes it worthwhile to continue working on improving their hydrotreating efficiency. According to our previous studies, the addition of Co or Ni promotes the hydrotreating activity, but only significant in the case of hydrodesulfurization efficiency (up to 30%). To increase the hydrodenitrogenation efficiency, other promoters, such as phosphorus, can be added. However, most of the published studies do not focus on co-processing or only on hydrotreating of gas oil model molecules at a laboratory scale. In this paper, we build on our previous research by studying five sulfur-free phosphorus-modified MoCx/Al2O3 catalysts (0.5, 1.5, 2.5, 3.5, and 4.5 wt %) for the hydrotreating of atmospheric gas oil and co-processing with rapeseed oil (5, 10, and 25 wt %) under industrial conditions (330–350 °C, 5.5 MPa, WHSV 1–2 h–1). A phosphorus content up to 1.5 wt % promoted the hydrodesulfurization (5–10%) and the hydrodenitrogenation (10–25%) efficiencies of catalysts. Moreover, the triglycerides addition did not significantly decrease the catalyst activity during co-processing. Therefore, our results enable us to define the range of phosphorus addition that enhances MoCx activity using industrial conditions and commercial feedstocks, pointing the way to develop a suitable and sulfur-free alternative to conventional hydrotreating catalysts.

Role of Catalyst in Optimizing Fluid Catalytic Cracking Performance During Cracking of H-Oil-Derived Gas Oils

Three H-Oil gas oils, heavy atmospheric gas oil (HAGO), light vacuum gas oil (LVGO), heavy vacuum gas oil (HVGO), and two their blends with hydrotreated straight run vacuum gas oils (HTSRVGOs) were cracked on two high unit cell size (UCS) lower porosity commercial catalysts and two low UCS higher porosity commercial catalysts. The cracking experiments were performed in an advanced cracking evaluation fluid catalytic cracking (FCC) laboratory unit at 527 °C, 30 s catalyst time on stream, and catalyst-to-oil (CTO) variation between 3.5 and 7.5 wt/wt The two high UCS lower porosity catalysts were more active and more coke selective. However, the difference between conversion of the more active high UCS lower porosity and low UCS higher porosity catalysts at 7.5 wt/wt CTO decreased in the order 10% (HAGO) > 9% (LVGO) > 6% (HVGO) > 4% (80% HTSRVGO/20% H-Oil VGO). Therefore, the catalyst performance is feedstock-dependent. The four studied catalysts along with a blend of one of them with 2% ZSM-5 were examined in a commercially revamped UOP FCC VSS unit. The lower UCS higher porosity catalysts exhibited operation at a higher CTO ratio achieving a similar conversion level with more active higher UCS lower porosity catalysts. However, the higher UCS lower porosity catalysts made 0.67% Δ coke that was higher than the maximum acceptable limit of 0.64% for this particular commercial FCC unit (FCCU), which required excluding the HVGO from the FCC feed blend. The catalyst system containing ZSM-5 increased the LPG yield but did not have an impact on gasoline octane. It was found that the predominant factor that controls refinery profitability related to the FCCU performance is the FCC slurry oil (bottoms) yield.

A predictive model of catalytic cracking: Feedstock-induced changes in gasoline and gas composition

One way to improve and predict unsteady processes of petroleum fuel production is to develop a mathematical model, that considers the feedstock composition. A study of various feedstock deep refining processes is particularly important. In this paper, we present the prediction of the catalytic cracking unit under feedstock base expansion by using oil fractions with a higher boiling point. The zeolite-containing catalyst with ZSM-5/Y ratio = 0.11 was used in this work. A new kinetic model involving the high molecular weight of C13–C40 hydrocarbons, gasoline groups, gas individual hydrocarbons and coke formation reactions was developed. The feed comprehensive studies, the development and application of a mathematical model allow assessing the feasibility of various feedstock types involvement. The impact of four feedstock types on the yield of catalytic cracking products, catalyst deactivation degree, gasoline and gas composition, and octane number were determined. Among the feedstocks under study are West Siberian oil vacuum gas oil, a mixture of Kazakhstan and West Siberian oil, a mixture of vacuum and atmospheric gas oil with residual feedstock (extract, slack waxes, petrolatum, deasphalting agent, raffinate), a mixture of vacuum distillate and residual feedstock (extracts, slack waxes).

Animal fats as a suitable feedstock for co-processing with atmospheric gas oil

Effects of animal fat addition in hydrotreated gas oil.

Statistical optimization of electrochemical conversion of heavy fuel oil to valuable products using response surface methodology

Mediated electro-membrane oxidation was employed to convert a refinery heavy fuel oil (HFO) to valuable liquid and solid products (heavy residuals) at mild conditions. Response surface methodology (RSM) was engaged to obtain maximum conversion of HFO by implementing the central composite design (CCD). Based on the prediction and optimization functions, the optimum conditions for HFO conversion were then established. When Ag (I) concentration, HFO content, electrolysis temperature and time were adjusted to 0.56 M, 1.2 wt. %, 32 °C and 11 min, respectively, the HFO converted to a liquid product comprising 10 % gasoline and kerosene, 20 % atmospheric gasoil, 40 % vacuum gasoil and 30 % vacuum residuals. These were very close to the model predictions representing reliability of the RSM technique.FTIR results after electrochemical conversion confirmed the production of branched aliphatic groups and regeneration of interacting hydroxyl and carbonyl groups for heavy residuals and liquid products. Sim-Dist results revealed that during the indirect electrolysis, cracking of the initial HFO to lighter products occurred. Besides, surface morphology of the heavy residuals showed formation of a calcined coke. Some pores and agglomerated asphaltenes were observed which are likely linked to the former presence of resinous components removed by electrolysis.

Oxalic Acid as a Hydrogen Donor for the Hydrodesulfurization of Gas Oil and Deoxygenation of Rapeseed Oil Using Phonolite-Based Catalysts.

The use of renewable local raw materials to produce fuels is an important step toward optimal environmentally friendly energy consumption. In addition, the use of these sources together with fossil fuels paves the way to an easier transition from fossil to renewable fuels. The use of simple organic acids as hydrogen donors is another alternative way to produce fuel. The present work reports the use of oxalic acid as a hydrogen donor for the catalytic hydrodesulfurization of atmospheric gas oil and the deoxygenation of rapeseed oil at 350 °C. For this process, one commercial NiW/SiO2–Al2O3 solid and two NiW/modified phonolite catalysts were used, namely Ni (5%) W (10%)/phonolite treated with HCl, and Ni (5%) W (10%)/phonolite treated with oxalic acid. The fresh phonolite catalysts were characterized by Hg porosimetry and N2 physisorption, ammonia temperature programmed desorption (NH3-TPD), X-ray diffraction (XRD), and X-ray fluorescence (XRF). The sulfided metal phonolite catalysts were characterized by XRD and XRF. Hydrodesulfurization led to a decrease in sulfur content from 1 to 0.5 wt% for the phonolite catalysts and to 0.8 wt% when the commercial catalyst was used. Deoxygenation led to the production of 15 and 65 wt% paraffin for phonolite and commercial solids, respectively. The results demonstrate the potential of using oxalic acid as a hydrogen donor in hydrotreating reactions.

Hydrotreating atmospheric gasoil and co-processing with rapeseed oil using supported Ni-Mo and Co-Mo carbide catalysts

Sulfur-free Mo carbide catalysts supported on Al2O3 and TiO2 have shown good activity during the co-processing of middle distillates with vegetable oils in prior studies. However, their hydrotreating activity is low compared with that of conventional hydrotreating catalysts. To increase the hydrotreating effectiveness, promoter metals, such as Ni or Co, can be added. This paper describes an extensive study on the use of four sulfur-free Ni-Mo and Co-Mo carbide catalysts (supported on Al2O3 and TiO2) for the hydrotreatment of atmospheric gasoil (AGO) and co-processing with rapeseed oil (RSO). The tests were conducted in a fixed bed reactor unit at 330–350 °C, 5.5 MPa, a weigh hourly space velocity (WHSV) = 1–2 h−1, and AGO/RSO of 100/0, 95/5, 90/10, and 75/25 wt.%. Analogous to conventional hydrotreatment catalysts, adding the promotor metals significantly increased the product quality and the hydrodesulfurisation and hydrodenitrogenation efficiencies at higher temperatures or at lower WHSVs. In the case of RSO co-processing, all the tested catalysts promoted the hydrodeoxygenation pathway instead of (hydro)decarboxylation/decarbonylation with an insignificant decrease in the hydrodesulfurization efficiency at lower AGO/RSO ratios. Therefore, our results suggest that promoting Mo carbide catalysts with Ni or Co significantly improves their catalytic properties, making them more competitive with conventional hydrotreating catalysts.