Heavy Components Research Articles

Differential hydrocarbon generation characteristics of organic matter with green algae and cyanobateria origins in the Permain Lucaogou Formation of the Santanghu Basin

Organic-rich fine-grained rocks are key carriers of unconventional oil and gas resources, making it crucial to understand their hydrocarbon generation and evolution characteristics. This study examines the fine-grained rocks of the second member of the Lucaogou Formation (P2l2) in the Tiaohu and Malang Sags of the Santanghu Basin, focusing on how different organic matter (OM) backgrounds - primarily green algae and cyanobacteria - affect hydrocarbon generation and crude oil properties. Kinetic analysis and hydrous pyrolysis experiments on shales rich in green algae, cyanobacteria, and their mixtures revealed that green algae - derived OM requires lower activation energy to initiate hydrocarbon generation, results in an earlier oil generation peak, and has a broader oil window. Conversely, cyanobacteria - derived OM needs higher activation energy to start hydrocarbon generation, has a later oil peak, and a more concentrated generation period. These findings led to two models: the "green algae origin - early hydrocarbon generation - early oil peak - broad oil window model" and the "cyanobacteria origin - late hydrocarbon generation - late oil peak - concentrated oil generation model." Correlation analysis showed that aromatic hydrocarbons, resins, and asphaltenes significantly degrade crude oil quality. Hydrous pyrolysis experiments indicated that the heavy component content (aromatic hydrocarbons + resins + asphaltenes) in liquid hydrocarbons follows the order: residual oil > absorbed oil > expelled oil, with content initially increasing and then decreasing with maturity, and the color change of liquid hydrocarbons in dichloromethane reflects heavy component content changes effectively. Calculations of density and viscosity of liquid hydrocarbons, based on heavy component content and crude oil properties, were compared with the longitudinal distribution of crude oil properties in the study area. Results show that the hydrocarbon generation characteristics of green algae and cyanobacteria control crude oil properties, highlighting significant intra-source differentiation in the P2l2 shale and validates the phase separation approach in hydrous pyrolysis experiments. The P2l2 shale, with its high OM content and substantial hydrocarbon generation, holds great potential for shale oil exploration, but both reservoir quality and crude oil property evolution under different OM backgrounds should be considered when selecting favorable areas.

Viscosity Reduction of Heavy Oil Based on Rice Husk Char-Based Nanocatalysts of NiO/Fe2O3

In recent years, catalytic hydrothermal cracking has gained significant attention as an effective technology for reducing the viscosity of heavy oil in the field of heavy oil recovery. However, the current catalyst temperature window is relatively high, leading to high energy consumption in heavy oil extraction. The development of catalysts that can effectively reduce the viscosity of heavy oil at low temperatures is important to reduce energy consumption in the thermal recovery process of heavy oil. Biochar-based catalysts exhibit good low-temperature activity. Therefore, this study used modified rice husk char as a carrier to develop NiO-RHC, Fe2O3-RHC, and NiO/Fe2O3-RHC catalysts, and investigated their performance in low-temperature catalytic viscosity reduction. Various methods were used to characterize the physical and chemical properties of the catalysts, and the effects of catalyst type and addition amounts on the catalytic viscosity reduction reaction were examined. The results showed that the catalytic performance of the dual-active component catalyst was better than that of NiO-RHC and Fe2O3-RHC. Under the catalysis of NiO/Fe2O3-RHC, the viscosity of heavy oil decreased by 81.81%. As the catalyst addition amounts increased, the viscosity reduction rate of heavy oil also increased. The optimal catalyst addition amount was 1.00wt.%, and the heavy component content in the oil sample was reduced by 4.14% after the catalytic reaction. Finally, the mechanism of heavy oil viscosity reduction was analyzed. It was found that the breaking of C-S bonds was a significant factor in reducing heavy oil viscosity, and the S in H2S mainly came from thioether and sulfoxide sulfur. This study provides valuable references for further research on low-temperature viscosity reduction in heavy oil.

Variations in Oil Occurrence State and Properties during High-Speed Stirring Treatment of Oily Sludge.

Oily sludge (OS) has long been regarded as a hazardous waste, and improper disposal may lead to serious environmental concerns and human health risks. Despite various methods having been proposed and applied to the treatment of OS, the oil occurrence states and properties in sludge are rarely characterized, which may directly link to the selection and effectiveness of treatment methods. Here, confocal laser scanning microscopy (CLSM), X-ray diffraction (XRD), gas chromatography (GC), and four components (SARA) analysis were utilized to characterize the changes in the oil occurrence states and compositions in OS samples before and after high-speed stirring (HSS) treatment. Our results show a substantial reduction in the oil concentration of OS after HSS treatment (from 32.98% to 1.65%), while SARA analysis reveals a similar oil composition before and after treatment, suggesting the broad applicability of HSS in removing oil and its insignificant selectivity towards various hydrocarbon components. This is further supported by the total petroleum hydrocarbon (TPH) analysis results, which show that the separated oil phase has a hydrocarbon composition similar to that of the original OS sample. The CLSM and fluorescence analysis suggest a homogeneous distribution of oil in the sludge, with relatively light components more concentrated in the pore systems between coarse mineral particles, whereas relatively heavy components tend to coexist with clay minerals. After HSS cleaning, both light and heavy components are removed to varying degrees, but light components are preferentially removed while heavy components tend to be retained in the sludge due to adsorption by clay minerals. This is consistent with TPH analysis, where a significant decrease in n-alkanes with lower carbon numbers (n-C14 to n-C20) was observed in the residual sample. Our findings demonstrate the dynamic response of oil occurrence states and compositions to the OS treatment process and highlight the importance of characterizing these fundamental properties prior to the selection of OS treatment methods.

Assessment of heavy metal concentrations in blood and radon concentrations in urine samples of workers at selected building material factories in Erbil, Iraq

ABSTRACT A total of 90 blood and urine samples were assessed to evaluate the health risks associated with radon and heavy metals in the Erbil Governorate. The worker group from the building materials manufacturers provided 70 samples, while an additional 20 samples were obtained from a control group. X-ray fluorescence technology was employed to measure and analyse the heavy metal content in the collected blood samples, while radon levels in the urine samples were analysed using a CR-39 detector. The findings indicate that the working group exhibits greater levels of radon and heavy components (Pb, Cd, and Ni) compared to the control group. The statistical analysis revealed that the levels of radon in urine samples of workers were significantly different (p ≤ 0.001) in certain factories, such as the cement plant, lightweight block, and red brick factories, compared to the control group. However, the levels were not statistically significant in other factories. The test showed significant differences in Pb concentrations between the employed and control groups (p < 0.05), with higher average values of Cd and Ni, but not statistically significant (P ˃ 0.05). The study found a positive correlation between the duration of employment and the average concentration of heavy metals (Pb, Cd, and Ni) in workers’ blood samples. Additionally, smokers and non-smokers had significantly different mean heavy element levels in their blood samples (p < 0.05). There is no statistically significant correlation between smoking status and radon levels (P ˃ 0.05). Remarkably, each urine sample had radon levels below the 200 Bq/m3 International Atomic Energy Agency standard, suggesting that urine is impurity-free. These results are critical and serve as baseline data in the Kurdistan region.

Regulation mechanism of phenol on intermediates during supercritical water gasification of coal

Supercritical water (SCW) gasification technology can enable the efficient utilization of coal by converting it to hydrogen-rich gas. However, poly-cyclic aromatic hydrocarbons and heavy components, which are intermediates of supercritical water gasification, tend to generate char, hindering the complete gasification of coal. In this work, phenol is recycled to enhance the gasification process and reduce the formation of these intermediates during SCWG, and the regulation mechanism is investigated. The results demonstrate that both gas yield and gasification efficiency increase with the presence of phenol, reaching approximately 98.5% at 750 °C, concentration of 2%with the effect of phenol, which is 27% higher than that in the coal-water system. Organics removal rate reaches about 98% with the addition of phenol. Phenol can enhance the gasification performance by facilitating the conversion of heavy components to lightweight components. The transient reactivity of coal in the poly-condensation stage is increased by about 50 times with the presence of phenol. The regulation mechanism of phenol in the poly-condensation stage during coal gasification involves the decomposition of SCW forming hydroxyl radicals, which replaces the substituents on the benzene ring, facilitating the dissociation of benzene ring into small molecules that are prone to polymerize. The interacting force between phenol and multi-rings disrupts the conjugate structure, aiding in the decomposition of polycyclic organics into small molecules.

Molecular insights into CO2 enhanced hydrocarbon recovery and its sequestration in multiscale shale reservoirs

CO2 huff-n-puff (HNP) is an attractive enhanced oil recovery (EOR) technique in shale development due to its low cost, high efficiency, and environmentally friendly feature. Molecular dynamics (MD) simulations have been widely used to investigate the mechanisms of CO2 HNP process. However, the process of CO2 HNP is highly complex, involving the CO2 adsorption and transport in multiscale porous media, while considering the effect of different hydrocarbon compositions of shale oil. In this work, we developed a novel multiscale model (nano + bulk) with the modified Eagle Ford shale oil and water as the reservoir fluid. We investigated the adsorption behaviors and transport dynamics of CO2 in the CO2 HNP process. We quantitatively evaluated the CO2 swelling effect and its miscibility with hydrocarbons. Our results show the preferential adsorption to the graphene wall is pentane < CO2 < octane. CO2 can effectively desorb the light and intermediate hydrocarbons from the graphene wall. In addition, CO2 has good swelling effect and miscibility with the light and intermediate components. Due to the large molecular diameter and the strong interactions with the nanopore wall, the heavy components tend to be trapped in the nanopore after the CO2 HNP process. However, CO2 has similar swelling effect on the light and heavy components, indicating that the heavy components in the bulk pore can be effectively swelled and produced. Different from the unstable diffusion edge in the inorganic nanopores, CO2 has a stable diffusion edge in the organic nanopores. From the adsorption perspective, CO2 has favorable sequestration performance in the inorganic nanopores in shale gas reservoirs. This work provides a comprehensive understanding of the CO2 HNP process and practical implications for CO2 sequestration in shale reservoirs.

In-situ hydrothermal upgrading and mechanism of heavy oil with nano-Fe2O3 in the porous media

Hydrothermal upgrading is a promising technology for heavy oil, yet the impact of reservoir conditions on the catalytic effect of catalysts and the pathway are not clear. In this study, the effect of the formation environment on the catalytic upgrading process was investigated through simulating the reservoir conditions (2000 mD permeability, 25 % porosity) for catalytic hydrothermal cracking of heavy oil. Under the hydrothermal upgrading conditions（240 ℃, 24 h, 50 wt%, 0.1 wt% nano-Fe2O3）, 9.15 % of the heavy component(5.1 % resin and 4.05 % asphaltene) was converted to light component. The content of hydrocarbons below C17 in the saturated fraction increased from 36.29 % to 59.85 %. The structure of the asphaltene was disrupted resulting in a lower level of asphaltene stacking, and NC/NH ratio increased 13.61 % compared to heavy oil. In addition, the reservoir condition with quartz as the supporting medium improved the catalytic ability of iron oxide nanoparticles. When injected into the reservoir medium, nano-size facilitated dispersion on the surface of the proppant and inhibited the aggregation of nanoparticles, which ensured the continuous operation of the active sites on the surface of the catalyst. Electron transfer of Fe2+/Fe3+ catalyzed the heterolytic cleavage of covalent bonds of H2O/heavy oil molecules was the mechanism for heavy oil upgrading. These findings demonstrated the feasibility of in-situ upgrading of heavy oil through the use of nano-catalysts under reservoir conditions.

Short-time and long-time dynamics of the zeolite films in the light of alternative diffusion models

Analysis of the dynamics of diffusion of two mixtures of hydrogen and heavier components through a flat zeolite film was carried out. The concepts of short-time and long-time dynamics were introduced. They derive from the observation of temporal trajectories obtained by applying abrupt perturbations of concentrations on one side of the membrane.An alternative description of the diffusion dynamics was proposed compared to the commonly accepted model that employs a matrix of thermodynamic factors Γ. In this way, the difficulty of analytical determination of this matrix for more complex adsorption equilibria was eliminated.The model equations were expressed in a matrix form, which enables its easy extension to any number of components. The proposed research methodology was illustrated using an example of diffusion of two selected mixtures, i.e. {H2, n-C4H10} and {H2, CO2} in silicalite-1. These gaseous mixtures have applications in specific technological processes.The two models were used to perform quantitative benchmarking of short-time and long-time dynamics of flat zeolite membranes. The assumed boundary conditions correspond to a semi-batch Wicke-Kallenbach diffusion cell. It was demonstrated that the phenomena occurring in short-time and long-time diffusion represent two different dynamic features important from a scientific and practical point of view.A quantitative measure for degree of confinement was proposed based on dynamic adsorption-desorption hysteresis.

Lessons Learned From Pandemic-Driven Remote Learning and Sustaining Best Practices in Turbomachinery Laboratory Experiences

Abstract As online educational experiences have become more common for students to engage with while earning an engineering degree, instructors must become more attuned to best practices in digital pedagogies for all courses, including those with heavy laboratory components. Despite potential resistance among faculty to the idea that a laboratory course does not require an in-person experience, pandemic-driven remote learning serves as an intrinsic data point in how, under dire circumstances, laboratory courses could be offered through a digital medium. This paper describes a collaborative autoethnography of four mechanical and aerospace engineering instructors regarding lessons learned while teaching laboratory courses online during the COVID-19 pandemic. To bolster the quality of the research design, an engineering education researcher facilitated the collaborative autoethnography and co-constructed the individual instructor narratives to elicit best practices in online pedagogy for turbomachinery educators.

The phase field method coupled with molecular dynamics parameter for simulating phase separation behavior of SBS modified asphalt

Polymer-modified asphalt is a thermodynamically unstable system, in which the polymer and asphalt are prone to phase separation. Due to the inadequacy of characterization methods for phase separation, this field has not been thoroughly understood or explored. This paper introduces an innovative methodology by employing a simulation approach that couples phase-field theory with molecular dynamics parameters. Using SBS polymer-modified asphalt as an example, validate the method's applicability and establish a more precise parameter library for the phase separation field model of SBS-modified asphalt. The phase separation process of SBS-modified asphalt was simulated. In combination with fluorescence microscopy experiments, the evolution of the micro and meso-phase states of the modified asphalt over time was established and tracked. Results indicate that higher light component content and lower heavy component content in asphalt improve its compatibility. Migration coefficients and interaction parameters for the phase field model were determined, and a more accurate correction factor for the entropy contribution of SBS-modified asphalt was estimated. The phase-field model shows that higher light component content and lower heavy component content result in slower and smaller phase separation, leading to better compatibility. The combined phase field and molecular dynamics simulations accurately reproduce experimental findings from fluorescence microscopy, providing theoretical references for studying phase separation in polymers.

Investigating the coking performance of ethylene residue pitch components

Ethylene residue pitch (ETP, the heavy component in ethylene residue tar) is widely used as a preferred raw material for preparing petroleum-based artificial carbon materials characterized by high carbon content, high aromaticity, and low heteroatom (S, N) content. To investigate the coking properties of ETP, eight components of ETP (four soluble and four insoluble components) were obtained via extraction and separation using methanol, n-butanol, n-hexane, and dimethyl sulfoxide as solvents. The thermal conversion (temperature = 500 °C) and carbonization treatment (temperature =1400 °C) were carried out on each pitch component. The basic physical properties of ETP components were observed using infrared spectroscopy, thermogravimetric analysis, and 1H-NMR. The microstructure of the petroleum-based pitch coke was studied using polarizing microscopy, X-ray single crystal diffraction (XRD), Raman spectroscopy, and scanning electron microscopy. The aromaticity of the insoluble components in ETP was slightly higher than that of soluble components, and the insoluble components had slightly fewer branching chains than those in soluble components. The microstrength of the ETP coke obtained using insoluble components was higher than that obtained using soluble components, and the true density of ETP coke HS-C was as high as 2.0554 g/cm3.

Modeling Solubility Induced Elemental Fractionation of Noble Gases in Oils

This study explores the estimation of solubility-induced elemental fractionation of noble gases in hydrocarbon-based oils through existing empirical and theoretical models, complemented by a novel molecular simulation-based approach. Quantifying such fractionation is essential for a deeper understanding of fluid processes and migration in subsurface geological resources, an area currently lacking in experimental data. To address this, the research introduces a predictive model that employs the Peng-Robinson equation of state and a fugacity-coefficient-based method to assess noble gas elemental fractionation in hydrocarbons, including normal alkanes, cycloalkanes, and aromatics. However, this model struggles with precise quantitative predictions, prompting the introduction of adjusted cross-interaction parameters to enhance its performance. Furthermore, molecular simulations, in conjunction with the refined equation of state, are shown to offer a novel method for calculating noble gas fractionation coefficients across different hydrocarbon solvents. A key finding is the identification of a universal master curve, demonstrating that noble gas solubility fractionation at low pressure in simple hydrocarbon solvents can be quantitatively determined by temperature and density alone, without the need for detailed compositional information. Consequently, a new correlation is proposed for deriving elemental fractionation coefficients based solely on oil temperature and density, offering significant improvements over existing empirical methods for a wide range of temperatures. Although limitations are noted when applying this approach to oils rich in complex heavy components like resins and asphaltenes, it allows to address inconsistencies observed in traditionally used experimental correlations at high temperatures.

Evaluation of rheological and microstructural behavior of modified asphalt binder with chitosan derived from shrimp shell powder

Chitosan derived from shrimp shells (SSPCH) was used for the first time as a biological biopolymer to modify the properties of bitumen across high, medium, and low-temperature ranges. Therefore, physical tests (penetration, softening point, and ductility) and rheological tests (RV, DSR, MSCR, LAS, and BBR) were conducted along with morphological and microstructural analyses, on modified bitumen with 2 %, 4 %, 6 %, and 8 % SSPCH. Chemical analysis revealed that bitumen and SSPCH interacted physically during the mixing process, while no chemical reaction was observed. Moreover, the thermal sensitivity of the modified bitumen was enhanced by decreasing the penetration degree and increasing the softening point. SSPCH improved the properties of modified bitumen as a result of its porous structure and asphaltene absorption, as well as its structural similarity to bitumen and ability to absorb the light components of bitumen with its heavy components. Increasing the SSPCH dose in bitumen improves its resistance to deformation and recoverability by increasing the viscous phase and decreasing the elastic phase, resulting in increased stiffness. The findings also revealed that the addition of 6 % SSPCH yielded the best performance against rutting failures. Generally, SSPCH incorporation significantly improved bitumen performance in different temperature ranges. By adding 8 % SSPCH, the highest resistance to rutting occurred. However, the phase separation between SSPCH and bitumen exceeded the suitable range. Hence, 6 % SSPCH is useful in the bitumen mixture for areas at high temperature. Also, to prevent fatigue and cracking damage, it is recommended to limit the dose of SSPCH to 4–6%.

Mechanism of thermal gravimetric difference between simulated and experimental of coal group components

Understanding the molecular mechanism underlying coal's thermal gravimetric behavior is crucial for advancing efficient and clean coal utilization technology, a task that remains challenging to address experimentally. ReaxFF molecular dynamic simulation has been widely applied across various systems and materials, particularly excelling in simulating combustion and pyrolysis processes with complex coal models. It is necessary to establish more connections between simulation and experiment, and to analyze and discuss the differences between them. This will lay the foundation for the reliability of simulation results in revealing experimental phenomena. In this study, coal was divided into four components using a full component classification method: the dense medium component, loose medium component, heavy component, and light component. The connections of the simulated and experimental thermal gravimetric behaviors of the coal group component skeletons were conducted, and founding the inconsistencies in the later stages of the curves. To understand these discrepancies, the test environments were analyzed, identifying the behavior of tar free radicals generated during pyrolysis as a key factor influencing the thermo-gravimetric curve. To mitigate the influence of tar free radicals and reduce the observed differences, a correction coefficient was introduced into the calculation formula for the yield of non-volatile products, achieving an improved alignment between the simulated and experimental thermo-gravimetric curves. This study significantly advances the application of ReaxFF molecular dynamics simulation in elucidating the mechanisms of coal pyrolysis.

Coupling aquathermolysis of water-heavy oil-methanol catalyzed by o-phenanthroline-Cu(II) complex at low temperature

In this study, a Cu(II) coordinated complex was synthesized using o-phenanthroline and copper chloride. The synthesized complex, serving as a aquathermolysis catalyst, significantly reduces heavy oil viscosity at lower temperatures. Studies indicate that at a reaction temperature of 200 °C, with a catalyst concentration of 0.1% and a reaction duration of 6 h, heavy oil viscosity significantly reduces. Heavy oil viscosity dropped from 392,000 mPa∙s to 63,000 mPa∙s, achieving an 83.93% reduction rate. This catalyst maintains superior catalytic performance at lower temperatures compared to other catalyst types. Using methanol as a hydrogen donor further enhances the catalyst’s effect, increasing the heavy oil viscosity reduction rate from 83.93% to 88.63%. Thermogravimetric, four-component, and elemental analyses reveal that aquathermolysis of heavy oil primarily occurs in its heavier components. Following the aquathermolysis reaction, there is an increase in light components and a decrease in impurity atoms in heavy oil, resulting in improved crude oil quality.

Measurement on the fatigue-healing performance of SARAs fractions in bitumen and its characterization by molecular simulations

The objective of this research was to investigate the healing characteristics of bitumen through the assessment of fatigue-healing performance of SARAs fractions and its characterization at the molecular level with SARAs fractions as the intermediate. Firstly, the flow behaviors and fatigue-healing performance of fractions were characterized by rheometer. Then, the diffusion systems were constructed and the diffusion with preset cracks was carried out, the evaluation of which was identified by density distribution, relative concentration in crack region, mean square displacement and interaction effect. The results indicate that aromatics exhibit the closest similarity to original bitumen in flowing behavior, which also reflected in the healing performance. The healing performance of resins and asphaltenes are extremely limited while that of saturates was comparable to fluid. Molecular simulation was further supporting to investigate the healing process. A platform period was found in the healing period when the molecules would move to seek the lowest energy state which was considered as healing in the alternative perspective. During the period, heavy components were more difficult to traverse while weak interaction between light components would shorten the period and identify the lowest energy state more easily, thereby greatly affecting the healing performance of fractions. Furthermore, heavy components are analogous to anchor points, among which resins were more readily aggregated and asphaltenes were relatively dispersed, while light components diffuse flexibly within them. The diffusion has the potential to drive the movement of heavy components which also kept the capture of other components, ultimately resulting in the formation of a stable healing state. The outcome with a discernible interaction effect would be important theoretical significance for the refinement of bitumen of better healing performance and the potential to influence the development of rejuvenators.

REMOVAL OF VARIOUS METAL IONS IN WATER BY DIFFERENT PRE-TREATMENTS OF FLY ASH

Rapid urbanisation in Malaysia has accelerated water pollution in rivers and other water sources, causing irreversible harm to the ecosystem. In view of that, this study aimed to work on using fly ash to address certain heavy metal components (chromium (Cr), copper (Cu), nickel (Ni), and zinc (Zn)) present in polluted water. The experiment employed three batches of fly ash. Two batches were treated with sodium hydroxide (NaOH-FA) and hydrochloric acid (HCl-FA), whereas one batch was left untreated (UFA). The three batches of adsorbents were examined by using a jar test after solutions containing 100 mg/L of Cr, Cu, Ni, and Zn ions were made. The results of various contact periods demonstrated that the fly ash had variable capacities for metal ion adsorption. The maximum adsorption of UFA was 79.958%(Cr), 80.814%(Cu), 81.580%(Ni), and 82.742%(Zn) while HCl-FA was adsorbing 77.148%(Cr), 82.546%(Cu), 78.896%(Ni), and 78.248%(Zn). NaOH-FA in this study was found to adsorb 80.828%(Cr), 79.230%(Cu), 81.692%(Ni), and 77.394%(Zn). Further to this, it was revealed that the Temkin Isotherm model was best fitted with the highest R² values (&gt; 0.98). The negative value of the slope, B indicated that the adsorption is an endothermic process which leans towards physical adsorption. In conclusion, this study demonstrated the successful application of fly ash in water or wastewater treatment of metal ions.

Mechanism of Rejuvenation in Aged SBS-Modified Asphalt by Density Functional Theory

As a large area of SBS-modified asphalt pavement entered the maintenance period, the aging and rejuvenation of SBS-modified asphalt have attracted attention in recent years. In order to further study the rejuvenation of aged SBS-modified asphalt, both rheological experiments and quantum mechanical simulations were used. Complex shear modulus (G*) and phase angle (δ) were used to analyze the rejuvenation effect of aged SBS-modified asphalt. Electron density, binding energy (Ebinding), and charge transfer number (Qtransfer) were used to observe the process of rejuvenation in aged SBS-modified asphalt. The results show that compared to asphalt components, SBS polymer was the least stable and most susceptible to breaking. After oxidative aging, SBS polymer with its aging products could impair the rejuvenation in aged asphalt. The interaction between aromatic components in rejuvenator and asphaltenes in aged asphalt was unstable and could be influenced by asphalt aging level. The interaction between heavy component molecules in aged asphalt with saturate component molecules in rejuvenator are closer than those with aromatic components molecules. The binding energies between saturate components in rejuvenator and asphaltenes in aged asphalt could be served as an evaluation indicator of rejuvenation.

Degradative solvent-catalyzed extraction of sewage sludge

It is necessary for the further development of sludge degradative solvent extraction (DSE) to significantly increase the bio-oil yield and adjust its composition. In this study, the effects of MCM-41, HZSM-5, and SSZ-13 on the physical properties, yield, and composition of bio-oil were compared. Results show that all three catalysts effectively promote the conversion of volatiles in the residue to the heavy component (heavy-s). The addition of MCM-41 improved the yieldof both the light component (light-s) and heavy-s. Their yields increased from 8.11% and 20.47% to 14.39% and 29.18%, respectively. Its all-silicon structure and weak acidity have no significant effect on the composition of the bio-oil. HZSM-5 addition increases the light-s yield to 25.58%. Its MFI structure and proper acidity are beneficial to the formation of aromatic hydrocarbons and olefins, while effectively reducing oxygenates. SSZ-13 increases the heavy-s yield to 27.89%, and promoted the formation of nitrogen-containing compounds significantly.

Inhomogeneous Fluid Transport Modeling in Dual-Scale Porous Media Considering Fluid-Solid Interactions.

Dynamics of fluid transport in ultratight reservoirs such as organic-rich shales differ from those in high-permeable reservoirs due to the complex nature of fluid transport and fluid-solid interaction in nanopores. We present a multiphase multicomponent transport model for primary production and gas injection in shale, considering the dual-scale porosity and intricate fluid-solid interactions. The pore space in the shale matrix is divided into macropores and nanopores based on pore size distribution. We employ density functional theory (DFT) to account for fluid-solid interactions and to compute the inhomogeneous fluid density distribution and phase behavior within a dual-scale matrix. The calculated fluid thermodynamic properties and transmissibility values are then integrated into the multiphase multicomponent transport model grounded in Maxwell-Stefan theory to simulate primary oil production from and gas injection into organic-rich shales. Our findings highlight DFT's adeptness in detailing the complex fluid inhomogeneities within nanopores─a critical concept that a cubic equation of state does not capture. Fluids within pores are categorized into confined and bulk states, restricted by a threshold pore width of 30 nm. Different compositions of fluid mixtures are observed in macropores and nanopores: heavier hydrocarbon components preferentially accumulate in nanopores due to their strong fluid-solid interactions. We utilize the developed model to simulate hydrocarbon production from an organic-rich shale matrix as well as CO2 injection into the matrix. During primary hydrocarbon production, strong fluid-solid interactions in nanopores impede the mobility of heavy components in the near-wall region, leading to their confinement. Consequently, heavy components mostly remain within the nanopores in the shale matrix during primary hydrocarbon production. During the CO2 injection process, the injected CO2 alters fluid composition within macropores and nanopores, promoting fluid redistribution. Injected CO2 engages in competitive fluid-solid interactions against intermediate hydrocarbons, successfully displacing a considerable number of these hydrocarbons from the nanopores.