Oil Upgrading Research Articles

Pulsed discharge plasma induced hydrogenation of aromatic compound in heavy oil: Reaction mechanism upon impact by operating conditions

Hydrogenation is an essential step for heavy oil upgrading by raising the H/C ratio but commonly requires high H2 pressure and high temperature. Non-thermal plasma provides a highly promising method for heavy oil hydrogenation at ambient conditions without a catalyst. Here we demonstrate a new approach to in-situ hydrogenation of ethylbenzene as heavy oil model compound using a pulsed dielectric barrier discharge plasma and examine the reaction mechanism upon impact by operating conditions. Results show that a higher H density is conducive to the aromatic ring hydrogenation, and the average H number added to the aromatic ring increases by ∼50% as the pulse repetition frequency increases. The high-energy electrons positively associated with the H radical density result in excessive cracking of ethylbenzene or the hydrogenated products, and the hydrogenation process is inhabited at high temperatures. Overall, a higher pulse repetition frequency, appropriate voltage amplitude, and lower temperature are determined to ensure the hydrogenation process. The present work may provide guiding principles for optimizing the reaction conditions for plasma-enabled aromatic ring hydrogenation and contribute to the future upgrading of heavy oils.

Utilization of Carbon Dioxide via Catalytic Hydrogenation Processes during Steam-Based Enhanced Oil Recovery

The concentration of carbon dioxide in the atmosphere has been increasing since immediately after the boom of industrialization. Novel technologies are required for carbon dioxide (CO2) capture, storage, and its chemical conversion into value-added products. In this study, we present a novel in situ CO2 utilization method via a hydrogenation process in the presence of nickel tallates during steam-based enhanced oil recovery. The light n-alkanes are the preferred products of in situ catalytic hydrogenation of CO2 due to their effective solubility, viscosity-reducing capacity, and hydrogen-donating capacity. A nickel tallate was evaluated for its carbon dioxide hydrogenation and oil-upgrading performance at 300 °C. The results showed that the content of saturated and aromatic fractions increased, while the content of heavier fragments decreased. Moreover, the relative content of normal C10–C20 alkanes doubled after the catalytic hydrogenation of CO2. Despite the noncatalytic hydrogenation of CO2, the viscosity was altered from 3309 mPa.s to 1775 mPa.s at a shear rate of 0.66 s−1. The addition of the catalyst further contributed to the reduction of the viscosity, down to 1167 mPa.s at the same shear rate. Thus, in situ catalytic hydrogenation of CO2 not only significantly reduces the concentration of anthropogenic carbon dioxide gas in the atmosphere, but it also enhances the oil-recovery factor by improving the quality of the upgraded crude oil and its mobility.

Study of hydrogen generation from heavy oil gasification based on ramped temperature oxidation experiments

Hydrogen is a clean energy because of its high energy density and pollution-free combustion. The main ways of hydrogen generation are from coal and methane, as well as hydrogen generation from by-products of chemical plants. It had been reported that heavy oil reservoir in Margaret Lake in Canada produced up to 15 mol% hydrogen indicating that it is feasible to produce hydrogen by in-situ gasification (ISG) from heavy oil reservoir. However, there are relatively few studies on the mechanism and characteristics of hydrogen generation from ISG of heavy oil, the lower limit of hydrogen-production temperature, the interaction of produced gas and so on. Previous studies focused on the upgrading of heavy oil rather than hydrogen generation. In order to study the hydrogen generation mechanisms of different samples, The 4 types samples covering heavy oil, light oil, carbon samples were used and the saturate, aromatic, resin and asphaltene (SARA) components was measured by thin layer chromatography and flame ionization detection (TLC-FID). Then, the ramped temperature oxidation (RTO) experiments of 7 Runs of reservoir cores and sand-filling model were designed. The compositions and molar contents of produced gas were analyzed combined with gas chromatography (GC), and the lower limit temperature and the advantages of hydrogen generation from heavy oil were analyzed under different air/nitrogen injection rates based on a constant water injection rate. The results showed that the lower limit temperature of hydrogen generation from crude oil was about 500–550 °C and that of carbon was 700–750 °C. The reservoir core may had catalytic effect, which can promote hydrogen production. The highest hydrogen rate of RTO experiment with reservoir core can reach 55–60mol%, while that of sand-filling experiment was only 5–10mol%. The main chemical reactions for hydrogen generation from crude oil were coke gasification and water-gas shift. Therefore, the hydrogen production of heavy oil with high hydrocarbon ratio was significantly greater than that of thin oil. It showed the advantages of hydrogen generation from heavy oil. In addition, in order to quantitatively evaluate the efficiency of hydrogen production by gasification, the definition and calculation equation of hydrogen generation efficiency (HGE) were given. The HGE was defined as the ratio of hydrogen production volume and hydrogen consumption volume in a certain period of time (Δt). The Ehg can be used to quantitatively represent HGE, and the calculation of Ehg is the ratio of hydrogen production and twice of oxygen consumption in a period of time. The Ehg of Run1 and Run3 were calculated to be 1.47 and 0.15. It indicated that the hydrogen production efficiency of Run1 was about 10 times higher than that of Run3.

Biochar-assisted upgradation of pyrolytic oil via slow pyrolysis of rice husk under a carbon dioxide environment

Biochar-assisted upgradation of pyrolytic oil via slow pyrolysis of rice husk under a carbon dioxide environment

A Theoretical and Experimental Approach to the Analysis of Hydrogen Generation and Thermodynamic Behavior in an In Situ Heavy Oil Upgrading Process Using Oil-Based Nanofluids

This study aims to show a theoretical and experimental approach to the analysis of hydrogen generation and its thermodynamic behavior in an in situ upgrading process of heavy crude oil using nanotechnology. Two nanoparticles of different chemical natures (ceria and alumina) were evaluated in asphaltene adsorption/decomposition under a steam atmosphere. Then, a nanofluid containing 500 mg·L−1 of the best-performing nanoparticles on a light hydrocarbon was formulated and injected in a dispersed form in the steam stream during steam injection recovery tests of two Colombian heavy crude oils (HO1 and HO2). The nanoparticles increased the oil recovery by 27% and 39% for HO1 and HO2 regarding the steam injection. The oil recovery at the end of the displacement test was 85% and 91% for HO1 and HO2, respectively. The recovered crude oil showed an increment in API° gravity from 12.4° and 12.1° to 18.5° and 29.2° for HO1 and HO2, respectively. Other properties, such as viscosity and content of asphaltenes and resins with high molecular weight, were positively modified in both crude oils. The fugacity of H2 was determined between the reservoir and overburden pressure and different temperatures, which were determined by the thermal profiles in the displacement test. The fugacity was calculated using the application of virial equations of state with mixing rules based on the possible intermolecular interactions between the components. Hydrogen acquired a higher chemical potential via nanoparticle presence. However, the difference in H2 fugacity between both points is much higher with nanoparticles, which means that hydrogen presents a lower tendency to migrate by diffusion to the high-pressure point. The difference between HO1 and HO2 lies mainly in the fact that the pressure difference between the reservoir and the overburden pressure is greater in HO2; therefore, the difference in fugacity is greater when the pressure differential is greater.

Numerical and experimental investigation of production performance of in-situ conversion of shale oil by air injection

In-situ conversion of oil shale process has been appealing from economic and energy security perspectives. Conventional in-situ upgrading techniques use electric heaters to heat oil shale, not shale oil. However, the efficiency of electrical heating method is very slow which requires preheating more than a year. Most conventional heating technologies focused on using different heat injection methods converting the shale oil reservoirs. As shale is a poor heat conductor, many of attempts are still in the laboratory stage. The shale oil matrix is very tight and the pore scale ranges from micro to nano-meter. In this paper, we propose to inject air into hydraulically fractured horizontal wells to create in-situ combustion of shale oil in ultra-low permeability formations. Heat is introduced into the formation through multistage fractured horizontal wells, which enhances the contact area of exposed kerogen. This process uses combustion reactants as fuel feed stock to generate perpetual heating. Firstly, we used the laboratory tube combustion of shale oil results to validate the simulation model. Then, we upscale the simulation model to investigate the well productivity performance by in-situ upgrading of shale oil by air injection.The main objective of this work is to determine the technical feasibility of recovering shale oil resources by air injection. It involves the application of hydraulic fracturing technology to enhance the kerogen exposure to oxygen. Heat flows from the fracture into shale oil formation, gradually converting the solid kerogen into mobile oil and gas which can be produced via fractures to the production wells. Our simulation results in this paper have shown the potential of in-situ combustion process to improved oil recovery in shale oil reservoirs. Simulation result indicates that the key parameters controlling the well productivity include air injection rate, injected gas composition and fracture spacing. The available literature provides limited studies on the applicability of in-situ combustion of shale oil in very low permeability formations. The paper provides a comprehensive model that allows kerogen to undergo thermal cracking and oxidation process. The results of this study indicate that the developed kinetic model is feasible to model the kerogen in-situ conversion process induced by air injection.

A semi-compositional approach to model asphaltene precipitation and deposition in solvent-based bitumen recovery processes

Steam assisted gravity drainage (SAGD), as a commercially proven high ultimate recovery process for heavy oil and bitumen is energy intensive and may be limited by high usage of water. In the recent years, numerous methods to combine solvent and heat have been proposed for the in-situ recovery of bitumen. Among these methods, N-Solv (heated solvent vapor injection) and EBRT (enhanced bitumen recovery technology) utilize heated solvent vapor to extract heavy crudes under in situ conditions. These methods take the advantage of partial in situ upgrading of oil with much lower consumptions of water and natural gas and have the potential to reduce greenhouse gas (GHG) emissions. However, with the current knowledge relevant to solvent/heat-assisted recovery processes, it still remained uncertain how the in-situ upgrading could impact ultimate recovery and the efficiency of these processes. This study, thus, aims at providing insights about these processes with a numerical model. The study develops a simulation model that captures important mechanisms involved in the processes such as diffusion/dispersion, solvent dissolution, asphaltene precipitation and potential deposition. The complexity of modelling such processes is due to interrelation of oil–gas phase behavior and fluid transport mechanisms combined with in situ upgrading of oil. The intention is not to only identify factors important to the modeling of these processes, but also find how robust simulation models can be developed to replicate observed field behavior. A semi-compositional approach, based on liquid–liquid equilibrium, is proposed to properly capture the asphaltene precipitation in thermal numerical simulators using direct lab measured data. Our analysis will be presented regarding upgrading mechanisms that should be implemented, their effect on the oil production rate, and techniques to model them.

Hydrothermal In-Reservoir Upgrading of Heavy Oil in the Presence of Non-Ionic Surfactants

The most widely applied methods to unlock heavy oil and natural bitumen resources in the world are still based on steam injection techniques. Improving the efficiency of hydrothermal processes poses a great challenge. The co-injection of various additives is practiced to lower the steam-to-oil ratio (SOR), viscosity alteration and to improve heavy oil properties. Organic solvents, non-condensable gases, air and surfactants are the preferred chemicals to be combined with steam. This study provides an investigation of the surfactant-assisted hydrothermal upgrading of heavy oil at 200 °C. The thermal stability and salt resistivity of two non-ionic surfactants (SA–3 and Biolub Green) were investigated. Moreover, the improved performance of the surfactants was established by performing an SARA analysis, elemental analysis, FT-IR spectroscopy, and EPR analysis, and by studying the viscosity reduction degree. The experimental results showed that surfactants lead to the in-depth destructive hydrogenation of the high-molecular components of heavy oil such as resins and asphaltenes. However, the content of light fractions increased. According to the results of the elemental analysis, the surfactants assist in the hydrodesulphurization of heavy oil. Overall, the physical and chemical consequences of hydrothermal upgrading in the presence of surfactants led to the irreversible viscosity reduction of heavy oil.

Selective hydrogenation and defunctionalization of heavy oil model compounds using an unsupported iron catalyst

Developing practical, inexpensive catalysts for the partial upgrading of crude oil is essential for converting heavy oil to meet pipeline standards without diluent. Here we report that air-stable unsupported iron sulfide nanoparticles derived from a single-source homogeneous precatalyst, Fe2S2(CO)6, are highly effective catalysts for the partial hydrogenation of substituted anthracenes and aromatic nitrogen and sulfur heterocycles. The reactivity of the anthracene series is governed by stereoelectronic effects imposed by the phenyl substituents, decreasing in the order anthracene > 9-phenylanthracene > 9,10-diphenylanthracene. Nitrogen- and sulfur-containing heterocycles are partially hydrogenated, with limited heteroatom removal for benzothiophene, showing that the unsupported iron sulfide catalyst is well-suited for the selective partial hydrogenation and limited defunctionalization, which are key for catalytic partial upgrading of heavy petroleum. The unsupported iron sulfide nanoparticles also catalyze hydrogenation of mixed “feeds” comprising combinations of model compounds, demonstrating that carbocyclic and heterocyclic molecules can be processed simultaneously with little self-inhibition of overall activity, a key requirement for compositionally challenging bitumen feeds. Several techniques were used to characterize the iron sulfide nanoparticles, as well as the organic reaction products. The heterogeneous catalyst, generated in situ, was more active than a ball-milled commercial iron sulfide catalyst. The heterobimetallic precatalyst Co2FeS(CO)9 does not enhance the rates of hydrogenation.

A Novel Approach in Understanding the Role of Water in Oxidation and Upgrading Reactions during In-Situ Combustion Oil Recovery, Part B: Interpretations

Summary To understand the role of connate water as a source of hydrogen in oxidation and upgrading of bituminous oil at high temperature, heavy water (D2O) and O-18 enriched water (H2O18) were used as connate water in two different in-situ combustion experiments using a conical tube. Aside from a fundamental understanding of the role of such reactions in in-situ combustion, the results could also potentially help in optimizing in-situ hydrogen generation and upgrading of heavy and bituminous oil. The conical tube had previously been used for understanding the impact of air flux in sustaining the combustion front (please see Alamatsaz et al. 2011Alamatsaz et al. 2012,2). Significant upgrading was observed in these tests with a produced API gravity of 35 °API compared to the original bitumen gravity of 9 °API. The produced fluids (gases and water) were analyzed with a mass spectrometer to demonstrate the effectiveness of using D2O and H2O18 as tracers in bitumen upgrading reactions and specifically to determine whether the H2O18 would be more effective than D2O in understanding the role of connate water. It was found that heavy water exchanges too readily with hydrogen atoms in the bitumen when the two are mixed. As a result, it could not be reliably used as an indicator for identifying the role of water. The run with O-18 enriched water, however, provided a better indication of water participation in the oxidation reactions. The results obtained from the mass spectrometry analysis of evolved gases and water samples collected in the second test showed that water does split during the reaction and O atoms of indigenous water molecules do combine with C atoms (from the hydrocarbon) to form CO2. These findings open the path for mechanistic considerations around the processes taking place during in-situ combustion and in-situ upgrading reactions.

Ex Situ Upgrading of Extra Heavy Oil: The Effect of Pore Shape of Co-Mo/γ-Al2O3 Catalysts

Co-Mo/γ-Al2O3 catalysts with different pore shapes were synthesized for the ex situ upgrading of extra heavy oils by hydrodesulfurization (HDS), hydrodemetallization (HDM), and hydrodeasphaltization (HDA). The catalysts were synthesized using aluminum oxides that were prepared by various methods. It was found that using the product obtained by the thermochemical activation of gibbsite leads to the formation of slit-shaped pores in aluminum oxide, while the application of the hydroxide deposition method by the precipitation of sodium aluminate and nitric acid gives cylindrical pores in aluminum oxide. Co-Mo catalysts synthesized using these two types of pores exhibit different catalytic activities. The catalyst synthesized on a carrier with cylindrical pores exhibited a higher catalytic activity in sulfur, heavy metals, and asphaltenes removal reactions that are synthesized on a carrier with slit-like pores. This is because the presence of cylindrical pores leads to a decrease in diffusion restrictions when removing large molecules of asphaltenes and sulfur-containing and metal-containing compounds.

Experimental Investigation of Metal-Based Calixarenes as Dispersed Catalyst Precursors for Heavy Oil Hydrocracking

Slurry-phase hydrocracking utilizing metal-containing oil-soluble compounds as precursors of dispersed catalysts is an effective approach for heavy oil upgrading. We propose applying metal-based p-tert-butylcalix[6]arene (TBC[6]s) organic species as dispersed catalyst precursors to enhance catalytic hydrogenation reactions involved in the upgrading of vacuum gas oil (VGO). Co- and Ni-based TBC[6]s were synthesized and characterized by SEM-EDX, ICP, XRD, and FT-IR. The thermogravimetric and calorimetric behaviors of the synthesized complexes, which are key properties of dispersed hydrocracking catalysts, were also explored. The experimental evaluation of the synthesized catalyst precursors show that the synthesized metal-based TBC[6] catalyst precursors improved the catalytic hydrogenation reactions. A co-catalytic system was also investigated by adding a commercial, first-stage hydrocracking supported catalyst in addition to the dispersed catalysts. The naphtha yields increased from 10.7 wt.% for the supported catalyst to 11.7 wt.% and 12 wt.% after adding it along with Ni-TBC[6] and Co-TBC[6], respectively. Mixing the metal-based precursors resulted in elevated yields of liquid products due to the in situ generation of highly active Co–Ni bimetallic dispersed catalysts.

A Novel Approach in Understanding the Role of Water in Oxidation and Upgrading Reactions during In-Situ Combustion Oil Recovery, Part A: Experimental Observations

Summary To understand the role of connate water as a source of hydrogen in oxidation and upgrading of bituminous oil at high temperature, heavy water (D2O) and O-18 enriched water (H2O18) were used as connate water in two different in-situ combustion experiments using a conical tube. Aside from fundamental understanding of the role of such reactions in in-situ combustion, the results could also potentially help in optimizing in-situ hydrogen generation and upgrading of heavy and bituminous oil. The conical tube had previously been used for understanding the impact of air flux (AF) in sustaining the combustion front (Alamatsaz et al. 2011). Significant upgrading was observed in these tests with a produced API gravity of 35 ° compared to the original bitumen gravity of 9 °API. This paper (Part A) deals with the experimental results including a comparison between conical tube and a combustion tube (CT) results. A subsequent paper (Part B) will discuss the upgrading aspects and the mass spectrometry results.

Sawdust biomass promotes aquathermolysis of extra-heavy oil

The application of biomass to the enhanced oil recovery of extra-heavy oil is a promising technology. In this paper, the promoting effect of sawdust on the viscosity reduction of extra-heavy oil was discussed. During the experiment, sawdust and extra-heavy oil were co-aquathermolysis. The experimental results showed that the viscosity of extra-heavy oil can be reduced from 145 Pa·s to 10.42 Pa·s at 553 K for 24 h and the feedstock ratio of sawdust: extra-heavy oil: water is 1:50:50. Elemental analysis of extra-heavy oil showed that the H/C increased from 1.4347 to 1.6296, and the oxygen content increased from 2.05 wt% to 5.61 wt%. Compared with the upgrading oil without sawdust, the viscosity decreased by 11.03 Pa·s and the H/C increased by 0.0832. The GC–MS results show that the dehydrogenation and deoxidation reactions of small molecular substances generated by sawdust provide hydrogen and oxygen sources for the upgrading of extra-heavy oil.

Catalytic upgrading of crude tire oil produced from hydrothermal liquefaction of scrap tire using Pd/Al2O3 nanocomposite

In this study, hydrothermal catalytic upgrading of crude tire oil was conducted in the presence of formic acid to decrease the viscosity, increase the high heating value (HHV), and improve the chemical composition of the liquid crude tire oil. Palladium nanoparticles immobilized on the surface of magnetic alumina (Pd/Al2O3/Fe3O4) were used as the catalyst. The catalyst had surface area of 101.67 m2/g and micropore volume of 0.31 cm3/g. Furthermore, EDS analysis showed that the palladium content of the catalyst was 2.29 wt%. Crude tire oil was produced by using the hydrothermal liquefaction process of scrap tire oil in presence of deionized water with a tire/water mass ratio of 1:4 in a molten salt bath using a cylindrical batch reactor. The effect of temperature (280–350 °C) and reaction time (20–120 min) on the upgrading process was evaluated. Finally, the Central Composite Design (CCD) method was applied for optimizing the process to increase mass and energy yield and improve the quality of the produced fuel. The mass yield of the produced fuel oil was in the range of 61 to 93 %. The results of the catalytic upgrading process illustrated that the content of sulfur and oxygen in the optimum state, compared to the crude tire oil, decreased by 86 % and 53 %, respectively; also, the HHV increased by 11 %.

Upgrading of hydrothermal liquefaction biocrudes from mono- and co-liquefaction of cow manure and wheat straw through hydrotreating and distillation

Liquid hydrocarbons from agricultural wet wastes can serve as a strategy to greatly reduce CO2 emissions. This study presents the upgrading via catalytic hydrotreatment of hydrothermal liquefaction (HTL) biocrudes derived from cow manure, wheat straw and their combined liquefaction (co-HTL). Four different temperatures were tested (340, 360, 380 and 400 °C) at constant hydrogen and biocrude flowrate. The co-HTL biocrude contained more recalcitrant nitrogen-containing molecules towards hydrotreatment, which caused decreased hydrogen consumption and overall lower quality of upgraded products. Generally, upgraded products were obtained with >80 wt% carbon yields based on biocrude input. Products of hydrotreatment at 400 °C were distilled into four cuts. Increased hydrotreatment temperature improved physicochemical properties of upgraded products, leading to generally higher yields of gasoline and kerosene through significant cracking of bottom residues. Bottom residues derived from single feedstock HTL biocrudes were totally miscible with fossil-derived vacuum gas oil at room temperature, while the co-HTL derived one required increased temperature for total solubility. We show that the co-HTL approach leads to a higher production of the diesel and bottom residue fractions. Overall, single feedstock HTL resulted in a carbon yield from biomass to upgraded oils of 34 and 38 % respectively for wheat straw and cow manure, while the co-HTL approach increased this value to 43 %. The combination of agribusiness waste for HTL processing is shown here to be an attractive solution for wet waste processing and carbon recovery towards advanced biofuels.

Direct Hydrogen Production from Extra-Heavy Crude Oil under Supercritical Water Conditions Using a Catalytic (Ni-Co/Al2O3) Upgrading Process

The generation of hydrogen from unconventional oil is expected to increase significantly during the next decade. It is commonly known that hydrogen is an environmentally friendly alternative fuel, and its production would partially cover the gap in energy market requirements. However, developing new cheap catalysts for its production from crude oil is still a challenging area in the field of petroleum and the petrochemical industry. This study presents a new approach to synthesizing and applying promising catalysts based on Ni, Co, and Ni-Co alloys that are supported by aluminum oxide Al2O3 in the production of hydrogen from extra-heavy crude oil in the Tahe Oil Field (China), in the presence of supercritical water (SCW). The obtained catalysts were characterized via scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area analysis, transmission electron microscopy (TEM), and, X-ray diffraction analysis (XRD). The obtained XRD data showed 3.22% of Co2+ in the Co/Al2O4 catalyst, 10.89% of Ni2+ in the Ni/Al2O4 catalyst, and 1.51% of Co2+ and 2.42% of Ni2+ in the Ni-CoAl2O3 bimetallic catalyst. The BET measurements of the obtained catalysts showed a surface area ranging from 3.04 to 162 m2/g, an average particle size ranging from 0.037 to 0.944 µm, and micropore volumes ranging from 0.000377 to 0.004882 cm3/g. The thermal, SCW, and catalytic upgrading processes of the studied samples were conducted in a discontinuous autoclave reactor for 2 h at a temperature of 420 °C. The obtained results revealed that thermal upgrading yielded 1.059 mol.% of H2, and SCW led to 6.132 mol.% of H2; meanwhile, the presence of Ni-CoAl2O3 provided the maximal rate of hydrogen generation with 11.783 mol.%. Moreover, Ni-CoAl2O3 and NiAl2O3 catalysts have been found to possess good affinity and selectivity toward H2 (11.783 mol.%) and methane CH4 (40.541 mol.%). According to our results, the presence of SCW increases the yield of upgraded oil (from 34.68 wt.% to 58.83 wt.%) while decreasing the amount of coke (from 51.02 wt.% to 33.64 wt.%) due to the significant amount of hydrogen generation in the reaction zone, which reduces free-radical recombination, and thus, improves oil recovery. Moreover, the combination of SCW and the synthetized catalysts resulted in a significant decrease in asphaltene content in the upgraded oil, from 28% to 2%, as a result of the good redistribution of hydrogen over carbons (H/C) during the upgrading processes, where it increased from 1.39 to 1.41 in the presence of SCW and reached 1.63 in the presence of the Ni-CoAl2O3 catalyst. According to the XRD results of the transformed form of catalysts (CoNi3S4), after thermal processing, heteroatom removal from extra-heavy crude oil via oxidative and adsorptive desulfurization processes is promoted. These findings contribute to the expanding body of knowledge on hydrogen production from in situ unconventional oil upgrading.

Upgrading of Sharqy Baghdad Heavy Oil via N-Hexane Solvent

Asphaltenes are a solubility class described as a component of crude oil with undesired characteristics. In this study, Sharqy Baghdad heavy oil upgrading was achieved utilizing the solvent deasphalting approach as asphaltenes are insoluble in paraffinic solvents; they may be removed from heavy crude oil by adding N-Hexane as a solvent to create deasphalted oil (DAO)of higher quality. This method is known as Solvent De-asphalting (SDA). Different effects have been assessed for the SDA process, such as solvent to oil ratio (4-16/1 ml/g), the extraction temperature (23 ºC) room temperature and (68 ºC) reflux temperature at (0.5 h mixing time with 400 rpm mixing speed). The best solvent deasphalting results were obtained at room temperature and 12 ml/g solvents to oil ratio. As a result, the API of DAO was increased by 9.3º compared to the API of Sharqy Baghdad heavy oil. The asphaltene reduction was 61.56%. The Sulfur removal was 32.8%, the Vanadium removal was 36.48%, and the Nickel removal was 46.21%.

Low-temperature in-situ synthesis of cerium oxide nanoparticles applicable in EOR processes: parametric study by Taguchi approach

In-situ synthesis of nanoparticles is a new approach to use nanoparticles in enhanced oil recovery (EOR) operations. This method synthesizes the nanomaterial under reservoir conditions and uses the reservoir's energy, which has several advantages over synthesizing these particles out of the reservoir and then injecting them into the reservoir by a dispersing fluid. Cerium oxide (CeO2) nanoparticles have very high surface energy and a very suitable catalytic property for absorbing organic substances (like crude oil) and breaking their molecules. These features can help the nanoparticles to be used in the EOR processes to recover more upgraded crude oil in heavy oil reservoirs. For the first time, this study synthesized CeO2 nanoparticles at low temperatures in crude oil as the reaction medium. Then, the Taguchi method was used to study the effects of different parameters on the size and quality of these materials. Various parameters such as pH, temperature, precursor salt concentration, and stirring time of the solution were selected to plan a design of experiment (DOE) project. Nanoparticle identification tests such as FTIR, XRD, and FESEM analyses determined nanoparticle crystalline properties, shape, morphology, and size. The results showed that high-quality CeO2 nanoparticles were produced in petroleum fluid using this study's proposed synthesis method. These nanoparticles have a spherical shape with sizes varying from 17 to 31 nm. Temperature had the most significant effect, and solution stirring time had the least impact on the crystal size of the CeO2 nanoparticles. Finally, the optimal conditions for synthesizing in-situ CeO2 nanoparticles were a combination of the temperature of 65 °C, pH of 10, the molarity of 0.55, and stirring time of 4 h.

Octahedral Cluster Complex of Molybdenum as Oil-Soluble Catalyst for Improving In Situ Upgrading of Heavy Crude Oil: Synthesis and Application

Heavy oil resources are attracting considerable interest in terms of sustaining energy demand. However, the exploitation of such resources requires deeper understanding of the processes occurring during their development. Promising methods currently used for enhancing heavy oil recovery are steam injection methods, which are based on aquathermolysis of heavy oil at higher temperatures. Regardless of its efficiency in the field of in situ upgrading of heavy oil, this technique still suffers from energy consumption and inefficient heat transfer for deeper reservoirs. During this study, we have developed a molybdenum-based catalyst for improving the process of heavy oil upgrading at higher temperature in the presence of water. The obtained catalyst has been characterized by a set of physico-chemical methods and was then applied for heavy oil hydrothermal processing in a high-pressure reactor at 200, 250 and 300 °C. The comparative study between heavy oil hydrothermal upgrading in the presence and absence of the obtained molybdenum-based oil soluble catalysts has pointed toward its potential application for heavy oil in situ upgrading techniques. In other words, the used catalyst was able to reduce heavy oil viscosity by more than 63% at 300 °C. Moreover, our results have demonstrated the efficiency of a molybdenum-based catalyst in improving saturates and light hydrocarbon content in the upgraded oil compared to the same quantity of these fractions in the initial oil and in the non-catalytically upgraded oil at similar temperatures. This has been explained by the significant role played by the used catalyst in destructing asphaltenes and resins as shown by XRD, elemental analysis, and gas chromatography, which confirmed the presence of molybdenum sulfur particles in the reaction medium at higher temperatures, especially at 300 °C. These particles contributed to stimulating hydrodesulphurization, cracking and hydrogenation reactions by breaking down the C-heteroatom bonds and consequently by destructing sphaltenes and resins into smaller fractions, leading to higher mobility and quality of the upgraded oil. Our results add to the growing body of literature on the catalytic upgrading of heavy oil in the presence of transition metal particles.