Oil Upgrading Research Articles

Experimental Study of Catalytically Enhanced Cyclic Steam-Air Stimulation for In Situ Hydrogen Generation and Heavy Oil Upgrading

The current study was performed for the experimental modeling of cyclic steam-air injection in a heavy oil reservoir model of dual porosity in the presence of a nickel-based catalyst for in situ oil upgrading enhanced by simultaneous hydrogen generation. The research was realized in the combustion tube setup with a sandpack core model under reservoir conditions due to the consistent injection of air followed by oil in situ combustion (ISC) and steam (water) injection. As a result, the original oil was upgraded regarding fractional composition and oil properties. In addition, simulated reservoir heterogeneity and cyclic stimulation intensified the hydrogen synthesis, which, in turn, could also contribute to oil upgrading.

Thermochemical Upgrading of Heavy Crude Oil in Reservoir Conditions

The purpose of this study is to enhance the quality of heavy oil through refinement using aquathermolysis with the simultaneous injection of steam and thermally stable nonionic surfactants (NS). To achieve this, the NS R-PPG of the nonionic type was synthesized, and the optimal product structures were characterized using infrared (IR) methods. Furthermore, the thermal stability of the synthesized NS R-PPG was investigated in line with the requirements for surfactants used in heavy oil applications. Subsequently, the study delved into investigating the hydrothermal upgrading of heavy oil with a catalyst, involving the joint participation of steam and surfactants at a temperature of 250 °C. Additionally, we assessed the improved oil characteristics resulting from the experimental process through SARA analysis, elemental analysis, GC, and viscosity reduction evaluations. The experimental results demonstrated distinct effects concerning the presence and absence of surfactants on heavy oil. Based on these findings, we conclude that surfactants play a crucial role in dispersing asphaltene clusters, thereby facilitating the decomposition process under mild thermobaric conditions, leading to a noticeable increase in the content of light fractions. Furthermore, as per the results of the elemental analysis, surfactants contribute significantly to the desulfurization of heavy oil. Overall, the incorporation of surfactants during hydrothermal upgrading resulted in an irreversible reduction in the viscosity of heavy oil, thereby enhancing its overall quality.

Development of a simple and efficient oil-soluble nanocatalytic system for aquathermolysis upgrading of heavy crude oil

Catalytic aquathermolysis is one of the key and cost-effective chemical method for recovering heavy oil. This process transforms the asphaltene and resin compounds of the oil into lighter fractions. Oil-soluble transition metal-based catalysts have been reported as efficient catalysts that improve the viscosity reduction efficiency of the aquathermolysis process. Previous studies have mainly focused on using long alkyl chains as oil-soluble ligands to prepare the catalysts. However, aromatic ligands that effectively interact with asphaltene and resin fractions have not been extensively studied. In other words, the molecular structure of ligand used in the catalyst synthesis significantly changes its activity in aquathermolysis. This study aims to fill this gap using catechol as a novel ligand to develop oil-soluble catalyst (Ni-OSC), which can interact with heavy oil fractions during aquathermolysis. Ni-OSC decreased the content of resin and asphaltene by 32.1% and 26.5%, respectively, and increased the amounts of saturated and aromatic hydrocarbons by 19.6% and 22.9%, respectively, compared to heavy oil. Moreover, a GC–MS study indicated that low molecular weight hydrocarbons in the composition of heavy oil increased, and the relative content of alkanes raised to 79% in the presence of Ni-OSC. The catalyst also increased the concentration of alkylbenzenes and naphthalenes in the composition of aromatic compounds, improving the quality and recovery of heavy oil. Furthermore, the viscosity of heavy oil was considerably reduced, and a maximum hydrogen to carbon ratio of 2.03 was observed in Ni-OSC system. To the best of our knowledge, this is the highest reported hydrogen-to-carbon ratio for catalytic aquathermolysis of heavy oil using oil-soluble catalysts.

Synthesis of mono, bi, and trimetallic Sn–Ni–Cu based ionic micro-emulsion catalysts and optimization of catalytic performance in heavy oil upgrading

In this study, to synthesize an active and feasible mono, bi, and trimetallic Sn–Ni–Cu/ionic microemulsion catalysts (IMECs), a novel synthesis process was proposed. All synthesized catalytic solutions and IMECs were characterized using conductivity, refractivity index (RI), inductively coupled plasma (ICP) and light microscope, physical stability, and Fourier transformed infrared spectroscopy (FTIR), respectively. Then, the interaction of catalyst formulation with operational parameters on the upgrading was experimentally evaluated. Statistical modeling was performed using the mixture-process algorithm of Design of Experiments (DOE). Experimental results and catalysts characterization specially FTIR outcomes reveal that shifting NO3−peaks of the trimetallic IMEC confirms the suitable preparation of IMEC. Moreover, trimetallic IMEC formulation of 23.09% Sn, 60.648% Ni, and 16.268% Cu which shows viscosity and produced gas weight percent (PGWP) of 586.99 cP and 1.269%, respectively, is the optimum catalyst formulation. Reaction temperature and catalysts wt% of 73 °C and 0.2% can be considered as the optimum operational condition. Finally, at 70 °C, increasing the amount of catalysts causes an increase in the speed of heavy to middle hydrocarbon reactions with reducing the effect of the mass transfer controlling mechanism. On the other hand, the reaction controlling mechanism for the production of light hydrocarbon from heavy oil was eliminated by changing the reaction temperature from 70 to 90 °C.

Assessing the economic and ecological viability of generating electricity from oil derived from pyrolysis of plastic waste in China

The increased plastic waste generation worldwide poses ponderous issues for public health and the environment. China is the highest generator of plastic waste around the world. The current treatment process (incineration) of the increased plastic waste causes dangerous environmental consequences. Pyrolysis has recently surfaced as an ecologically friendly technique for energy and material recovery from plastic waste. The present study assesses the financial and ecological viability of power production from oil derived from the pyrolysis of mixed plastic wastes in China from 2009 to 2028. The prominent findings show that the amount of plastic waste collected in 2020 (24.16 Mt) increased by 53.19% in 2028.The pyrolysis of mixed plastic wastes during the project period yielded 359.29 Mt oil, which has a power potential of 1,060.86 GWh. The economic analysis indicated the project is viable and profitable with a positive net present value (US$8.80 million) and profitability index (1.26) greater than 1. The project has 10.6 y payback period, US$0.0752/kWh levelized cost of energy, 22.5% return on investment, and 13.0% internal rate of return. The life cycle assessment results show that conversion of mixed plastic waste to pyrolysis oil for electricity generation during the project period has a total global warming potential (GWP) of 1,311.4 kt CO2eq. The GWP is mainly from conversion of pyrolysis oil to electricity (73.42%), pyrolysis oil production (15.01%) and upgrading of pyrolysis oil (11.38%). The consumption of power from the project could avoid the combustion of 2,659.0 t coal, minimizing global warming by 11,278.8 kt CO2eq. Sensitivity analysis, which examines the influence of variation in sensitive factors on the success of the project, is presented. This paper provides scientific strategies for optimal investment and decision-making on the environmental sustainability of plastic waste-to-energy pyrolysis projects.

Comparative Catalytic Study for Upgrading Mexican Heavy Crude Oil

In this work, the study of three transition metal mixtures: cobalt-molybdenum (CoMo), nickel-molybdenum (NiMo), and nickel-cobalt-molybdenum (NiCoMo) with phosphorus supported on a γ-Al2O3 were studied for the hydroprocessing of heavy crude oil. The different metallic compositions were incorporated on gamma-alumina support by incipient wetness impregnation. The materials obtained were dried at 110°C and calcined to 450°C (4 h). The catalysts were evaluated using a Parr stainless steel batch reactor at 10.6 MPa and 380°C, for one hour. Mexican heavy crude oil named Ku-Ma-Loob Zaap was used and characterized according to its chemical composition: saturates, asphaltenes, resins, and aromatics (SARA). Sulfur and nitrogen were also determined by chemiluminescence techniques. The physical measurements for qualifying the transport properties were API gravity and kinematic viscosity. Among the tested catalysts, NiCoMoP/γ-Al2O3 presented the highest activity, increasing the API gravity from 12.6 to 24.5°API and decreasing the kinematic viscosity from 9.896 to 45 cSt at 25°C. The increasing activity was strongly related to the reducibility of the metals and weakly to the metals content. The surface area and pore volume did not change with the amount of metal, so no effect related to these properties was observed. Phosphorus presence was not discussed, since approximately the same amount was used in the three samples. However, it is known that phosphorus increased the hydrotreating activity due to the increased acidity of the catalyst, making trimetallic catalysts more active than bimetallic ones. In terms of the chemical composition of the upgraded crude oil, it was evident that the asphaltenes, sulfur, and nitrogen contents decreased sharply.

Current Status and Future Trends of In Situ Catalytic Upgrading of Extra Heavy Oil

In situ catalytic upgrading of heavy oil decomposes viscous heavy oil underground through a series of complex chemical and physical reactions with the aid of an injected catalyst, and permits the resulting lighter components to flow to the producer under a normal pressure drive. By eliminating or substantially reducing the use of steam, which is prevalently used in current heavy oil productions worldwide and is a potent source of contamination concerns if not treated properly, in situ catalytic upgrading is intrinsically environmental-friendly and widely regarded as one of the promising techniques routes to decarbonize the oil industry. The present review provides a state-of-the-art summarization of the technologies of in situ catalytic upgrading and viscosity reduction in heavy oil from the aspects of catalyst selections, catalytic mechanisms, catalytic methods, and applications. The various types of widely used catalysts are compared and discussed in detail. Factors that impact the efficacy of the in situ upgrading of heavy oil are presented. The challenges and recommendations for future development are also furnished. This in-depth review is intended to give a well-rounded introduction to critical aspects on which the in situ catalytic application can shed light in the development of the world’s extra heavy oil reservoirs.

Rational design of Ni-MoO3–x catalyst towards efficient hydrodeoxygenation of lignin-derived bio-oil into naphthenes

Design of a robust catalyst with high activity but the low cost for the hydrodeoxygenation (HDO) of bio-oils is of great importance to bring the biorefinery concept into reality. In this study, density functional theory (DFT) calculation was adopted to analyze the optimal location of Ni on MoO3–x containing oxygen vacancy, and the corresponding result demonstrated that metallic Ni cluster located at the neighborhood of oxygen vacancies would significantly evoke HDO activity. Enlightened by DFT results, NiMoO4 was first hydrothermally synthesized and then employed to fabricate Ni-MoO3–x catalyst via a low-temperature reduction, where Ni escaped from NiMoO4 and was reduced to its metallic state. Such an evolution of Ni species also induced the formation of oxygen vacancies around metallic Ni cluster. In the HDO of p-cresol, Ni-MoO3–x exhibited high activity with a complete conversion and a methylcyclohexane selectivity of 99.4% at 150 °C. Moreover, the catalyst showed good versatility in catalyzing HDO of diverse lignin-derived oxygenates and lignin oil. 2D HSQC NMR, gas chromatograph and elemental analysis of the lignin oil demonstrated the high deoxygenation efficiency and saturation of the benzene ring over Ni-MoO3–x. In the upgrading of crude lignin oil, the deoxygenation degree was up to 99%, and the overall carbon yield of the naphthenes was as high as 69.4%. Importantly, the structures and carbon numbers of the naphthene products are similar to jet fuel-range cycloalkanes, which are expected to have a high density that can be blended into jet fuel to raise the range (or payload) of airplanes. This work demonstrates the feasibility for improving the targeted catalytic reactivity by rational tailoring the catalyst structure under the guidance of theoretical analysis, and provides an energy-efficient route for the upgrading of lignin crude oil into valuable naphthenes.

Comprehensive analysis of geothermal energy integration with heavy oil upgrading in hot compressed water

In this study, a combined cycle of geothermal energy and heavy oil upgrading in hot compressed water (HCW) is investigated for electricity generation. The proposed approach offers efficient desulfurization and reduced carbon dioxide emissions, as renewable energy supplies part of the energy needed for the upgrading process. The performance of the superstructure is analyzed through energy, exergy, economic, exergoeconomic analysis and environmental assessments, revealing improvements in cycle exergy efficiency (21.67%) and total system cost rate (3.79 $/s). Additionally, a multi-objective optimization of the system is conducted using artificial neural network coupled with genetic algorithm, resulting in optimal values of 23.85% for cycle exergy efficiency and 2.62 $/s for total system cost rate. The integration of geothermal energy in this system leads to a reduction of global carbon dioxide emissions by 479.16 kton/year, resulting in savings of approximately 11.5 M$/year in environmental costs. Finally, a case study demonstrates a mitigation of local sulfur dioxide emissions caused by heavy oil consumption by approximately 177.86 kton/year.

Techno-economic and life cycle assessment of renewable diesel production via methane-assisted catalytic waste cooking oil upgrading

In this work, a techno-economic and life cycle assessment of a novel catalytic methane-assisted process for the production of renewable diesel has been performed. A systematic method for calculating catalyst production cost is engaged via CatCost utilization. The results are compared with commercial processes (hydrotreatment and alkali-catalyzed process) and other recently published research. The total capital investment in hydrotreating of WCO (hydrocracking of long chain fatty acids by hydrogen under high pressure and temperature) and alkali-catalyzed process (transesterification of fatty acids by NaOH to produce fatty acid methyl ester) are 39% and 97% more than that of the novel methane-assisted catalytic process, respectively. The consumed energy per unit mass of produced renewable diesel calculated from this innovative upgrading technique is 0.93 kW/kg of renewable diesel, which is remarkably lower than that for the aforementioned commercial processes. The production costs have also been investigated and it was found that using natural gas is noticeably cheaper than hydrogen employed for the hydrotreating process and NaOH and methanol used in alkali catalyzed process. The production costs for the methane-assisted catalytic process are 0.365 $/kg renewable diesel and for hydrotreating and alkali-catalyzed process, the production costs are 0.574 $/kg renewable diesel and 0.513 $/kg biodiesel, respectively. The economic results have also been compared with other research and it was found the total production cost of the new process is minimum, however total capital investment is a bit high. The results of the life cycle assessment (LCA) have also proved the advantages of the newly developed process because using NaOH and methanol in the alkali-catalyzed process and hydrogen in the hydrotreating process would have higher environmental impacts. The impact assessment showed that the proposed process contributes significantly to reducing global warming since CO2eq results indicate that the proposed process emits remarkably less CO2 as one of the major greenhouse gases compared to other processes. For examining the risk of investment, the Monte Carlo simulation with 1000 iterations has also been conducted and the results manifest the high profitability of this process.

Aquathermolysis of Heavy Crude Oil: Comparison Study of the Performance of Ni(CH3COO)2 and Zn(CH3COO)2 Water-Soluble Catalysts

Aquathermolysis is one of the crucial processes being considered to successfully upgrade and irreversibly reduce the high viscosity of heavy crude oil during steam enhanced oil recovery technologies. The aquathermolysis of heavy oil can be promoted by transition metal-based catalysts. In this study, the catalytic performance of two water-soluble catalysts Ni(CH3COO)2 and Zn(CH3COO)2 on the aquathermolytic upgrading of heavy oil at 300 °C for 24 h was investigated in a high pressure–high temperature (HP-HT) batch reactor. The comparison study showed that nickel acetate is more effective than zinc acetate in terms of viscosity reduction at 20 °C (58% versus 48%). The viscosity alteration can be mainly explained by the changes in the group composition, where the content of resins and asphaltenes in the upgraded heavy crude oil sample in the presence of nickel catalyst was reduced by 44% and 13%, respectively. Moreover, the nickel acetate-assisted aquathermolysis of heavy oil contributed to the increase in the yield of gasoline and diesel oil fractions by 33% and 29%, respectively. The activity of the compared metal acetates in hydrogenation of the crude oil was judged by the results of the atomic H/C ratio. The atomic H/C ratio of crude oil upgraded in the presence of Ni(CH3COO)2 was significantly increased from 1.52 to 2.02. In addition, the catalyst contributed to the desulfurization of crude oil, reducing the content of sulfur in crude oil from 5.55 wt% to 4.51 wt% The destructive hydrogenation of resins and asphaltenes was supported by the results of gas chromatography-mass spectroscopy (GC-MS) and Fourier-transform infrared (FT-IR) spectroscopy analysis methods. The obtained experimental results showed that using water-soluble catalysts is effective in promoting the aquathermolytic reactions of heavy oil and has a great potential for industrial-scale applications.

Hydrodeoxygenation of Pyrolysis Oil in Supercritical Ethanol with Formic Acid as an In Situ Hydrogen Source over NiMoW Catalysts Supported on Different Materials

Hydrodeoxygenation (HDO) is one of the most promising approaches to upgrading pyrolysis oils, but this process normally operates over expensive noble metal catalysts (e.g., Ru/C, Pt/Al2O3) under high-pressure hydrogen gas, which raises processing costs and safety concerns. In this study, a wood-derived pyrolysis oil was upgraded in supercritical ethanol using formic acid as an in situ hydrogen source at 300 °C and 350 °C, over a series of nickel–molybdenum-tungsten (NiMoW) catalysts supported on different materials, including Al2O3, activated carbon, sawdust carbon, and multiwalled nanotubes (MWNTs). The upgrading was also conducted under hydrogen gas (an ex situ hydrogen source) for comparison. The upgrading process was evaluated by oil yield, degree of deoxygenation (DOD), and oil qualities. The NiMoW/MWNT catalyst showed the best HDO performance among all the catalysts tested at 350 °C, with 74.8% and 70.9% of oxygen in the raw pyrolysis oil removed under in situ and ex situ hydrogen source conditions, respectively, which is likely owing to the large pore size and volume of the MWNT support material, while the in situ hydrogen source outperformed the ex situ hydrogen source in terms of upgraded oil yields and qualities, regardless of the catalysts employed.

Catalytic HDO of pyrolysis oil in supercritical ethanol with CoMoP and CoMoW catalysts supported on different carbon materials using formic acid as in-situ hydrogen sources

The work investigated performances of several CoMoP and CoMoW catalysts supported on different carbon materials in catalytic hydrodeoxygenation (HDO) of pyrolysis oil in supercritical ethanol using formic acid as an in-situ hydrogen source. Among them, the CoMoP catalyst supported on ZnCl2 activated sawdust carbon (ASC-Zn) and the CoMoW catalyst supported on multi-walled carbon nanotubes (MWNTs) showed the best HDO performance at both 300 °C and 350 °C for 2 h, obtaining higher upgraded oil yield, lower oxygen contents of the upgraded oils, and higher degrees of deoxygenation (DOD). Whereas the stability tests with three HDO cycles showed that both catalysts were slightly deactivated likely by active metals leach-out or coke/carbon deposition on active sites of the catalysts.

Ferrocene-based catalysts for in-situ hydrothermal upgrading of heavy crude oil: Synthesis and application

In this work, the effect of synthesized Ferrocene-based ligand catalysts, including Mono-, Di- and Tri-Ferrocene, as additives for promoting the catalytic in-situ hydrothermal upgrading of Tatarstan (Russia) heavy crude oil was studied. In addition, the changes in composition of upgraded oil samples as well as the in-situ transformation and characteristics of used catalysts were evaluated in detail using comprehensive analyzing techniques. All of the catalytic and non-catalytic hydrothermal upgrading experiments were carried out under the steam stimulation conditions at 300 °C, 72 bar (1044.27 psi) and 24 h of reaction time. The results show that introducing Ferrocene-based ligand catalysts to the upgrading system promotes the in-situ upgrading of heavy crude oil and improves the physical and chemical properties of upgraded oil samples. The maximum viscosity reduction was observed in presence Tri-Ferrocene and reached around 40% compared to non-catalytic hydrothermal upgrading. In addition, the upgrading performance also reflects in increase of H/C ratio, reduction of sulfur content, increase of saturates and aromatics, and decrease of the content of resins and asphaltenes as well as a noticeable change (increase) in the light fractions of C10-C20 are observed for all upgraded oil samples. Mono-Ferrocene as an oil-soluble catalyst mainly transformed to the particles of Fe3O4 (Magnetite) and FeS, which can act as active forms of catalysts and accelerate the hydrothermal conversion of heavy crude oil and its heavy fractions including resins and asphaltenes. These transformations were confirmed using XRD, SEM-EDX and Mössbauer analyzing techniques. Generally, the good catalytic performance of used ferrocene-based ligand catalysts as well as their low cost and commercial availability makes them great potential catalysts for improving the efficiency of steam injection for heavy oil production and in-situ upgrading.

Changes in structural parameters of SARA fractions during heavy oil hydrocracking using dispersed catalysts

Most of the characterization of SARA fractions of heavy crude oils during hydrocracking reactions is focused only on asphaltenes, and scarce works are devoted to analyze the differences in the structural parameters of all SARA fractions. In this work, a heavy crude oil is upgraded by non-catalytic and catalytic hydrocracking in a batch reactor at low severity conditions (3.9 MPa H2 pressure, 380 °C temperature, 800 rpm stirring rate, and 4 h reaction time). Three ore catalysts (hematite, magnetite and molybdenite) and one analytical grade catalyst (iron oxide) are employed. After reaction, the upgraded oils are first distilled and then separated into SARA fractions by the ASTM D86-16a and ASTM D2007-11 methods, respectively. NMR (1H and 13C), FTIR and GPC analyses are used to characterize SARA fractions before and after hydrocracking. The hydrocracking products exhibited a reduction in the average molecular weight of all SARA fractions as function of the hydrogenation capacity of each catalyst in the following order: Fe2O3 (analytical grade) > Molybdenite > Hematite > Magnetite. The structural parameters of saturates fraction remains unchanged except for the production of small length aliphatic chains from heavier fractions. For aromatics, resins and asphaltenes fractions, the number of aliphatic carbons is reduced due to dealkylation reactions increasing their aromaticity. For resins and asphaltenes fractions, hydrogenation and ring opening reactions are also carried out. Mo-based catalyst is mainly aimed at the conversion of asphaltenes, while the Fe-based catalysts focused on the conversion of resins.

Preparation of graphene supported Ni–Fe bimetallic nanocatalyst and its catalytic upgrading and viscosity reduction performance for heavy oil

Graphene supported single metal catalyst can improve the dispersion of active components and enhance the viscosity reduction effect of heavy oil. However, there is little research on graphene-supported bimetallic catalysts in the field of heavy oil upgrading and viscosity reduction. In this paper, super heavy oil of Liaohe Oilfield was taken as the research object. Graphene was selected as the carrier material, and nickel and iron chlorides were used as precursors. Graphene-supported nickel-iron bimetallic nanocatalysts were prepared by solvothermal method, and their synthesis feasibility was proved by microscopic characterization. Then the prepared catalyst was used in the evaluation experiment of catalytic upgrading and viscosity reduction performance of Liaohe heavy oil. By analyzing the parameters of oil samples before and after catalytic upgrading and viscosity reduction, the catalytic upgrading and viscosity reduction effect was evaluated and the viscosity reduction mechanism was revealed. The results showed that the viscosity reduction rate of heavy oil with graphene supported Ni–Fe bimetallic catalyst was 42.38%. With the aid of decalin, the viscosity reduction rate of heavy oil could reach 71.43%. At this time, the content of heavy components, the average molecular weight of heavy components and the aromaticity fA of oil samples decreased after catalytic upgrading and viscosity reduction, while the aromatic condensation degree HAU/CA and the branched chain index BI increased, and the modification effect was significant. Among them, the average molecular weight of asphaltene decreased from 2266 to 1444, with the most obvious decrease. The decrease of heteroatom content in asphaltene led to a significant decrease in intermolecular force and hydrogen bonding, which was the main reason for the catalytic upgrading and viscosity reduction of heavy oil by graphene supported Ni–Fe bimetallic catalyst.

Chemical Viscosity Reduction of Heavy Oil by Multi-Frequency Ultrasonic Waves with the Main Harmonics of 20–60 kHz

Ultrasound technologies are well-known for their ability to intensify the heat and mass transfer processes. Hence, ultrasonic treatment processes are widely applied for the separation of oil–water emulsions, optimization of oil pumping processes, cleaning the bottomhole zone, etc. However, the main phenomenon under the positive influence of ultrasonic waves on such processes is the cavitation bubbles implosion on the water–oil boundary. It is well-known that ultrasound energy contributes to the reversible viscosity reduction in heavy oil systems. However, it is possible to exhibit chemical destruction of the weakest carbon–heteroatom bonds in the structure of the asphaltenes. This study investigates the influences of controllable ultrasound waves with frequency ranges of 20–60 kHz under the exposure time of 60 s on the rheology of a heavy crude oil sample produced from the Ashalcha reservoir (Tatarstan Republic, Russia). The specific feature of this study is the application of multi-frequency ultrasonic exposure with a wide spectrum of side harmonics with the frequency up to 400 kHz. The results of the Saturates, Aromatics, Resins and Asphaltenes (SARA) analysis method support the chemical consequences of ultrasonication of crude oil. The content of resins under the irradiation of ultrasound waves altered from 32.5 wt.% to 29.4 wt.%, while the number of aromatics hydrocarbons raised from 24.3 wt.% to 34.1 wt.%. The Gas Chromatography—Mass Spectroscopy (GC-MS) analytical analysis method was applied to qualitatively compare the composition of saturated and aromatics fractions between the initial and upgraded heavy crude oil in order to show the chemical destruction of asphaltene bonds after the ultrasonic treatment. It was demonstrated that ultrasound waves allowed chemical conversion of asphaltene fragments that led to irreversible viscosity reduction. The viscosity of the heavy oil sample under the favorable ultrasonic irradiation conditions reduced from 661.2 mPa·s to 178.8 mPa·s. This advantage can be used to develop enhanced oil recovery methods and partial upgrading processes in downstream conditions.

CO2-H2O assisted co-pyrolysis of petroleum vacuum residue and polypropylene to improve asphaltene reduction and coke suppression: A statistical approach

Non-catalytic co-pyrolysis of petroleum vacuum residue (VR) and polypropylene (PP) was studied under CO2 and/or steam atmospheres in a batch condition. A statistical approach was performed to analyze the effect of temperature, CO2 initial pressure, reaction time, PP and water contents using fractional factorial design methodology. A comparison of co-pyrolysis in steam, CO2, and steam + CO2 atmospheres showed that CO2 + steam is a more effective environment for reduction of asphaltene and suppressing coke formation. In detail, steam dominated the pyrolysis process, whereas CO2 enhanced the thermal cracking reactions, thereby increasing the asphaltene conversion to maltene and decreasing coke formation. Moreover, the results indicated that the addition of PP to VR improved the yield and quality of the liquid product and diminished the coke content. The optimum conditions were the temperature of 380 °C, CO2 initial pressure of 0.6 MPa, reaction time of 90 min with PP/ VR and water/ VR ratios of 0.23, and 0.25 (g/g), respectively. Pyrolysis of VR under such conditions resulted in the 86% maltene yield, 89.7% asphaltene reduction and 6.3% coke reduction. 1H NMR analysis showed that paraffins occupy the major content of the liquid (81.07 vol%), followed by aromatics (12.28 vol%) and olefinic compounds (6.65 vol%). In addition, the upgraded oil had a remarkable °API gravity of 35.9 and a low viscosity of 5.27 ± 0.02 cP. Furthermore, heavy metals of Ni and V were removed from the liquid product by 56.1% and 65.6%, respectively. Pyrolysis of VR with PP in the CO2 + steam environment would be deemed an economically viable and environmentally friendly technique of transforming the abundant low-grade VR feedstocks to valuable liquid fuels at a milder processing condition without using any catalysts.

Uniform Ni species encapsulated in nanocrystalline ZSM–5 with enhanced catalytic performance for upgrading of fatty acids

Acid hydrolysis of silicon source with ethylenediamine complexed Ni as metal precursors was used to synthesis a hierarchical ZSM–5 zeolite supporting Ni catalyst by one-pot method. After sequenced hydrothermal synthesis, calcination and reduction, highly dispersed Ni nanoparticles (NPs) encapsulated in hierarchical ZSM–5 catalyst (Ni@HZ) was obtained. The prepared catalyst was used for upgrading of fatty acids under H2 atmosphere. The Ni@HZ catalyst composed of nanocrystalline aggregates (∼100 nm), induced the generation of abundant intercrystallite mesopores, which promoted the diffusion of the reactants. Moreover, the uniformly distributed Ni NPs internal of nanocrystalline show high thermal stability, thus facilitating the adsorption and spillover of active hydrogen. High conversion rate of palmitic acid and stearic acid with deep deoxygenation were achieved by the synergism of acid and Ni species. Moreover, hierarchical pores in Ni@HZ catalyst improved the selectivity of isomeric products, which benefited the cold flow properties of the upgraded oil.

Optimization of reaction temperature and Ni–W–Mo catalyst soaking time in oil upgrading: application to kinetic modeling of in-situ upgrading

Decreasing the conventional sources of oil reservoirs attracts researchers’ attention to the tertiary recovery of oil reservoirs, such as in-situ catalytic upgrading. In this contribution, the response surface methodology (RSM) approach and multi-objective optimization were utilized to investigate the effect of reaction temperature and catalysts soaking time on the concentration distribution of upgraded oil samples. To this end, 22 sets of experimental oil upgrading over Ni–W–Mo catalyst were utilized for the statistical modeling. Then, optimization based on the minimum reaction temperature, catalysts soaking time, gas, and residue wt.% was performed. Also, correlations for the prediction of concentration of different fractions (residue, vacuum gas oil (VGO), distillate, naphtha, and gases) as a function of independent factors were developed. Statistical results revealed that RSM model is in good agreement with experimental data and high coefficients of determination (R2 = 0.96, 0.945, 0.97, 0.996, 0.89) are the witness for this claim. Finally, based on multi-objective optimization, 378.81 °C and 17.31 h were obtained as the optimum upgrading condition. In this condition, the composition of residue, VGO, distillate, naphtha, and gases are 6.798%, 39.23%, 32.93%, 16.865%, and 2.896%, respectively, and the optimum condition is worthwhile for the pilot and industrial application of catalyst injection during in-situ oil upgrading.