Energy & Fuels最新文献

To further elucidate the modification effects of polyphosphoric acid (PPA) on different oil-source base asphalts from the perspective of the mechanical properties of asphalt colloidal components, an improved separation device was designed to isolate colloidal components from PPA-modified and unmodified asphalts derived from different oil-source regions. The rheological properties of the maltene components were evaluated across a broad temperature range using a dynamic shear rheometer. The nanomechanical properties of solid-state asphaltenes were examined using atomic force microscopy. The variations in polarity and solubility of resins and aromatics induced by PPA were quantified by thin-layer chromatography with flame-ionization detection (TLC-FID). The results indicated that PPA significantly increased the complex modulus of resins by 2.5 to 3 times. The enhancement effect of 115-grade PPA generally exceeded that of 105-grade PPA. TLC-FID confirmed that PPA simultaneously polymerized rigid aromatic fragments and cyclized alkyl segments in the aromatic and resin fractions. By polymerizing active sites in asphaltenes, PPA introduced a small amount of ultrahard substance into the Derjaguin–Muller–Toporov (DMT) modulus image of the asphaltenes, a phenomenon more pronounced with long-chain PPA. This resulted in increases of 7.4% to 25.6% in the maximum DMT modulus and 10 to 30 MPa in the average DMT modulus of the asphaltenes. This study innovatively investigated the effects of PPA on different oil-source asphalts from the perspective of the mechanical properties of the four components, revealing the material transformation mechanisms within asphalts under the influence of PPA and the reasons for the differences in modification effects among asphalts with different molecular structures. Moreover, the research methodology provides a reference for studies of other chemically modified asphalts.

Hydraulic fracturing has considerable potential for stimulating natural gas hydrate reservoirs (NGHRs). However, hydrate dissociation-induced mechanical weakening of sediments, together with gas–water two-phase flow-driven fine particle migration, poses significant engineering challenges, including proppant embedment and fracture plugging, which severely degrade fracture conductivity. This study employed a visual sapphire reactor to investigate the effects of proppant-filled layers on hydrate formation and dissociation behavior. X-ray computed tomography (X-ray CT) was further utilized to characterize fine particle migration patterns and pore-structure damage within the proppant-filled layer. The results indicate that conductivity impairment predominantly occurs during the constant-pressure stage and the subsequent gas output stage. Increasing proppant concentration and reducing proppant particle size significantly mitigate conductivity damage while enhancing gas production rates. Moreover, a gradient-filling strategy using 20–40 and 40–60 mesh proppants effectively optimized fracture conductivity, yielding total porosity increases of 84.6% and 23.9%, respectively, relative to uniform proppant filling. Additionally, pore-structure damage was found to vary nonlinearly with decomposition pressure, highlighting a coupled relationship between damage severity and gas–water two-phase flow velocity, which in turn influences particle migration intensity and spatial distribution. These findings provide valuable guidance for optimizing proppant gradation and developing effective protective strategies, and offer a useful reference framework for integrating hydraulic fracturing and sand control to support sustainable and stable gas production from hydrate reservoirs.

Petroleum is a complex matrix, with its physical and thermodynamic properties, as well as mixture behavior, primarily dependent on its constituents and their relative quantities. Adequate characterization of crude oil constituents is indispensable for determining its thermodynamic behavior and is of great importance for all stages of its value chain from reserve estimation to projects for production, lifting, transportation, refining, and distribution of its derivatives. Consequently, there is significant interest in conducting in-depth studies of its composition. High-resolution mass spectrometers have been employed universally to analyze petroleum, giving rise to the field of petroleomics. High-field techniques such as Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and Orbitrap MS are fundamental in petroleomics studies. Nevertheless, the high resolution of these instruments introduces certain sample variations and spectral alignment challenges. To address these limitations, data processing methodologies have been developed to align, concatenate, and correct baseline distortions in the spectra of complex matrices. This article aimed to conduct a systematic investigation of the development of chemometrics (multivariate analysis, machine learning, or artificial intelligence) in petroleomics applied to high-resolution instruments such as FT-ICR MS and Orbitrap MS.

The resource utilization of oil sludge (OS) is considered a feasible and environmentally friendly approach to effectively address the disposal of OS effectively. In this work, a preformed particle gel (PPG) system was prepared by using OS, which could serve as a high-strength plugging material for conformance control. Based on the free-radical copolymerization method, the OS-PPG was developed by adjusting the chemical composition of the formulation. The effects of each component and its concentration in OS-PPG on the swelling performance and rheological behavior were systematically investigated. Infrared spectroscopy and simultaneous thermal analyses were employed to characterize the structure and thermal stability. The plugging strength was evaluated with a pore-network fluid-loss meter. Results showed that when using 5.71–20.00% monomer (i.e., acrylamide and 2-acrylamido-2-methylpropanesulfonic acid), 0.1–0.5% PCS, 0.05–0.1% MBA, and 0.05–0.4% APS, OS-PPGs with high OS content (20%) could be prepared. The maximum swelling ratio in formation water reached 43.5 times. The storage modulus (G′) was 216.4 Pa, the complex viscosity (η*) was 35514.9 mPa·s, and the maximum plugging strength reached 0.88 MPa, demonstrating good structural strength. The gel particles possessed a stable three-dimensional network structure with OS physically dispersed through a filling mode. The initial decomposition temperature of the system was 246 °C, about 31 °C higher than that of conventional PPG, indicating good thermal stability. This study provided a new method for direct resource utilization of OS in oilfields and offered a novel material with promising application prospects for green profile modification and water plugging in oilfields.

The resource utilization of oil sludge (OS) is considered a feasible and environmentally friendly approach to effectively address the disposal of OS effectively. In this work, a preformed particle gel (PPG) system was prepared by using OS, which could serve as a high-strength plugging material for conformance control. Based on the free-radical copolymerization method, the OS-PPG was developed by adjusting the chemical composition of the formulation. The effects of each component and its concentration in OS-PPG on the swelling performance and rheological behavior were systematically investigated. Infrared spectroscopy and simultaneous thermal analyses were employed to characterize the structure and thermal stability. The plugging strength was evaluated with a pore-network fluid-loss meter. Results showed that when using 5.71–20.00% monomer (i.e., acrylamide and 2-acrylamido-2-methylpropanesulfonic acid), 0.1–0.5% PCS, 0.05–0.1% MBA, and 0.05–0.4% APS, OS-PPGs with high OS content (20%) could be prepared. The maximum swelling ratio in formation water reached 43.5 times. The storage modulus (G′) was 216.4 Pa, the complex viscosity (η*) was 35514.9 mPa·s, and the maximum plugging strength reached 0.88 MPa, demonstrating good structural strength. The gel particles possessed a stable three-dimensional network structure with OS physically dispersed through a filling mode. The initial decomposition temperature of the system was 246 °C, about 31 °C higher than that of conventional PPG, indicating good thermal stability. This study provided a new method for direct resource utilization of OS in oilfields and offered a novel material with promising application prospects for green profile modification and water plugging in oilfields.

Catalytic pyrolysis of byproducts after lipid extraction of microalgae with HZSM-5 is inefficient in converting heavy intermediates, primarily due to the catalyst’s pore-size constraints and the feedstock’s high nitrogen content. To promote the diffusion and cracking of these heavy and nitrogen-rich compounds, NaOH solution was used to pretreat HZSM-5 for tailoring its pore structure and acidity distribution. The effect of NaOH concentration in modifying HZSM-5 and its influence on the aromatic hydrocarbons (AHs) production and denitrogenation (DeN) were systematically investigated via pyrolysis–gas chromatography and mass spectrometry (Py–GC/MS) at a pyrolysis temperature of 500 °C. The quantitative evaluation of deoxygenation and denitrogenation performance as well as the correlation of zeolite properties and AH production/DeN was studied. Results demonstrated that NaOH-treated HZSM-5 retained the MFI topology while developing substantial mesoporosity. The 0.05MZ (0.05 M NaOH-treated) catalyst exhibited an 8.0% increase in strong acid sites, leading to about 73% and 86% reductions in amides and N-heterocyclic compounds, respectively, while doubling the nitrile yield. The corresponding deoxygenation and denitrogenation efficiencies reached 0.91 and 0.49, respectively. Optimal aromatic hydrocarbon production was achieved with the 0.1MZ (0.1 M NaOH-treated) catalyst, showing an 11% increase in relative yield compared to that of HZSM-5. A negative correlation was observed between the mesopore volume and the formation of AHs, while strong acidity was positively correlated with both AHs production and denitrogenation. These findings may guide the optimization of HZSM-5 catalysts to enhance the molecular diffusion and shape selectivity for heavy nitrogen-containing compounds from microalgae pyrolysis.

Gas-phase dimethyl ether (DME) carbonylation to methyl acetate (MA) is prone to be deactivated by coke depositions on Brønsted acid sites (Si-OH-Al groups) of ferrierite zeolite, and those inevitable coke depositions on the active sites, especially in eight-membered ring (8-MR) channels, are required to be regenerated through in situ removal of coke precursors in a circular fluidized-bed reactor (FBR) for its stable operation. The bench-scale FBR system was applied to verify optimal regenerative treatment conditions and to study behaviors of spray-dried FER zeolites ∼60 μm in size after regeneration. Those inactive coke precursors were effectively removed with small structural disintegrations of the FER zeolite under an air environment at 500 °C at a slow ramping rate of 1 °C/min among the tested range of 1–25 °C/min. Although the high regeneration temperature (∼500 °C) compared to the lower regeneration temperature of 300–400 °C caused slight decreases of Si-OH-Al sites assigned to Brønsted acid sites, the catalytic activity was almost recovered at those optimal regeneration conditions with an almost complete removal of coke precursors. The stable maintenance of active sites and original sphere shapes was clearly observed during 5 successive cycles of gas-phase DME carbonylation reaction at 240 °C and regenerative treatment at ∼500 °C at a fixed pressure of 5.0 MPa, which were attributed to the appropriate removal of surface coke precursors in the 8-MR channels without any significant structural disintegration.

Gas-phase dimethyl ether (DME) carbonylation to methyl acetate (MA) is prone to be deactivated by coke depositions on Brønsted acid sites (Si-OH-Al groups) of ferrierite zeolite, and those inevitable coke depositions on the active sites, especially in eight-membered ring (8-MR) channels, are required to be regenerated through in situ removal of coke precursors in a circular fluidized-bed reactor (FBR) for its stable operation. The bench-scale FBR system was applied to verify optimal regenerative treatment conditions and to study behaviors of spray-dried FER zeolites ∼60 μm in size after regeneration. Those inactive coke precursors were effectively removed with small structural disintegrations of the FER zeolite under an air environment at 500 °C at a slow ramping rate of 1 °C/min among the tested range of 1–25 °C/min. Although the high regeneration temperature (∼500 °C) compared to the lower regeneration temperature of 300–400 °C caused slight decreases of Si-OH-Al sites assigned to Brønsted acid sites, the catalytic activity was almost recovered at those optimal regeneration conditions with an almost complete removal of coke precursors. The stable maintenance of active sites and original sphere shapes was clearly observed during 5 successive cycles of gas-phase DME carbonylation reaction at 240 °C and regenerative treatment at ∼500 °C at a fixed pressure of 5.0 MPa, which were attributed to the appropriate removal of surface coke precursors in the 8-MR channels without any significant structural disintegration.

Layered two-dimensional MXene materials exhibit tremendous potential in energy storage applications due to their high conductivity and adjustable surface chemistry. However, weak interlayer adhesion between nanosheets and self-aggregation effects induced by van der Waals interactions often lead to uncontrolled stacking phenomena of layers, significantly limiting their practical utilization in flexible energy storage devices. Addressing these challenges, herein, a free-standing nanolamellar Ti₃C₂T_x–OH/carboxymethyl cellulose-poly(3,4-ethylenedioxythiophene): polystyrenesulfonate (Ti₃C₂T_x–OH/CMC-PEDOT:PSS) hybrid film was designed as an electrode material for a flexible supercapacitor (FSC) through a convenient vacuum-assisted filtration strategy. CMC serves as an in situ polymerization template for EDOT, guiding the ordered growth of PEDOT chains to form an interconnected conductive network that suppresses PEDOT:PSS self-aggregation; simultaneously, hydrogen bonding between CMC and PEDOT strengthens interfacial interactions within the film. Serving as a multifunctional intercalator, CMC-PEDOT:PSS synergistically leveraged spatial steric hindrance and electrostatic repulsion to expand the interlayer spacing of Ti₃C₂T_x, while constructing efficient ion/electron transport channels. Furthermore, -F terminals on Ti₃C₂T_x replaced with −OH generated abundant electroactive sites for redox reactions. Benefiting from these interfacial engineering strategies and optimized structural design, the hybrid film exhibited remarkable mechanical strength (73 MPa tensile strength), outstanding electrical conductivity (75.6 S cm^–1), and excellent areal specific capacitance (2968 mF cm^–2 at 4 mA cm^–2). Moreover, the assembled symmetric supercapacitor (SSC) device delivered a high areal energy density of 94.8 μWh cm^–2 at 1600 μW cm^–2 power density while maintaining 84.3% initial capacitance after 5000 cycles, demonstrating superior energy storage performance and cycling stability.

Layered two-dimensional MXene materials exhibit tremendous potential in energy storage applications due to their high conductivity and adjustable surface chemistry. However, weak interlayer adhesion between nanosheets and self-aggregation effects induced by van der Waals interactions often lead to uncontrolled stacking phenomena of layers, significantly limiting their practical utilization in flexible energy storage devices. Addressing these challenges, herein, a free-standing nanolamellar Ti₃C₂T_x–OH/carboxymethyl cellulose-poly(3,4-ethylenedioxythiophene): polystyrenesulfonate (Ti₃C₂T_x–OH/CMC-PEDOT:PSS) hybrid film was designed as an electrode material for a flexible supercapacitor (FSC) through a convenient vacuum-assisted filtration strategy. CMC serves as an in situ polymerization template for EDOT, guiding the ordered growth of PEDOT chains to form an interconnected conductive network that suppresses PEDOT:PSS self-aggregation; simultaneously, hydrogen bonding between CMC and PEDOT strengthens interfacial interactions within the film. Serving as a multifunctional intercalator, CMC-PEDOT:PSS synergistically leveraged spatial steric hindrance and electrostatic repulsion to expand the interlayer spacing of Ti₃C₂T_x, while constructing efficient ion/electron transport channels. Furthermore, -F terminals on Ti₃C₂T_x replaced with −OH generated abundant electroactive sites for redox reactions. Benefiting from these interfacial engineering strategies and optimized structural design, the hybrid film exhibited remarkable mechanical strength (73 MPa tensile strength), outstanding electrical conductivity (75.6 S cm^–1), and excellent areal specific capacitance (2968 mF cm^–2 at 4 mA cm^–2). Moreover, the assembled symmetric supercapacitor (SSC) device delivered a high areal energy density of 94.8 μWh cm^–2 at 1600 μW cm^–2 power density while maintaining 84.3% initial capacitance after 5000 cycles, demonstrating superior energy storage performance and cycling stability.