Energy & Fuels最新文献

The effective development of unconventional petroleum systems requires the use of significant water resources. In an effort to reduce the consumption of freshwater resources for hydraulic fracturing, highly saline produced waters are increasingly recycled for use as a base fluid. However, there are significant knowledge gaps regarding potential water–rock interactions resulting from the introduction of produced waters and associated additives into shale reservoirs such as formation and deposition of mineral scale, which can negatively affect hydrocarbon production through wellbore restriction and damage to hydraulically generated fractures. To assess the impacts of field stimulation practices in the subsurface, a series of laboratory experiments were completed using (a) three distinct sedimentary rock formations of the Midland Basin (Texas, USA) and (b) additives with two different base fluids: municipal fresh water and clean brine. The experimental approach used relevant injection sequences and mixing ratios in specialized reactors for 3 weeks. Static pressurized experiments and nonpressurized time-resolved experiments were undertaken. The resulting solids and liquids were analyzed by using a variety of laboratory- and synchrotron-based techniques. The use of an acid spearhead (15% HCl) resulted in texturing of both clay-rich and calcareous shales, which can temporarily enhance porosity but subsequently result in mineral scale deposition. The primary matrix scale was Fe(III)-bearing phases, which occurred in all experiments regardless of base fluid chemistry. Additionally, strontium sulfate (SrSO₄) precipitated on shale surfaces when clean brines were used. It was concluded that clean brine was the main source of Sr²⁺ species, while persulfate breaker degradation and oxidation of pyrite were the sources of SO₄^2–. Sulfate scaling was more pronounced in clay-rich shales, suggesting that Sr sorption is important for promoting celestite formation. This work demonstrates that mineral scale deposition is a complex phenomenon, whereby the type and proportions of various mineral phases are determined from reservoir alteration processes and coprecipitation of constituents from injection fluids. The experimental results shown here should be considered when evaluating different base fluids and additives in order to mitigate mineral precipitation in unconventional shale reservoirs, which could result in reservoir degradation.

The coproduction of hydrogen and valuable products driven by the electrocatalytic glycerol oxidation reaction has recently garnered increasing attention. However, the poor active centers and high charge resistance of the utilized anode material could be considered as the primary issues, limiting overall glycerol oxidation performance. This work presents the development of a novel Co–N–C@NF electrocatalyst involving the participation of collagen, serving as a coordinative agent for the first time. The employed characterizations unveil the existence of Co–N–C-species-anchored nickel foam. Such a unique architecture, possessing numerous active sites and facilitating charge transportation, results in an outstanding electrocatalytic glycerol oxidation reaction. Thus, the Co–N–C@NF electrode delivers a low operating potential of 1.32 V vs RHE at 10 mA·cm^–2. Furthermore, the Co–N–C@NF catalyst also shows high Faradaic efficiency and selectivity values toward H₂ and formic acid, as confirmed by NMR analysis, respectively. These findings highlight the promising application of the Co–N–C@NF catalyst as a robust candidate for glycerol-oxidation-reaction-driven hydrogen and value-added chemical production.

A promising technology for producing carbon-neutral fuels is fluidized-bed gasification of biomass. In combination with chemical looping gasification (CLG), the process becomes even more efficient. However, using biomass-based fuels can lead to significant ash-related issues, including bed agglomeration, fouling, deposition, slagging, and high-temperature corrosion. To address these issues, several biomass upgrading approaches are used to improve the quality of the feedstock for gasification. These approaches include torrefaction, water leaching, and blending with different additives. This study focuses on the influence of additives and biomass co-blending with low-cost biofuels on the behavior of inorganic constituents and under gasification-like conditions at 950 °C and the corresponding impact in fluidized-bed gasification. For example, blending (upgraded) barley straw with 2 wt % CaCO₃ resulted in a decrease in slag and a corresponding increase in the proportion of solid oxides. This indicates that thermal stability can be expected at operating temperatures up to 950 °C. Similarly, adding Ca/Si-rich biowaste components increases the ash softening point of herbaceous biofuels. Furthermore, the results show that adding Ca-based or woody biofuel components has a chemical effect on the fate of volatile inorganics. For example, increasing the concentration of calcium in the fuel significantly reduces the release of HCl and partially reduces the release of sulfur species, thus reducing the corrosion risk. These results contribute to the development of more efficient and cleaner biomass gasification processes for producing carbon-neutral fuels.

Ionic liquids (ILs) have attracted considerable attention in energy storage due to their unique properties, including a wide electrochemical stability window that facilitates their use in high-voltage systems, enhancing the battery energy density. For instance, the electrolyte consisting of polyethylene glycol diacrylate (PEGDA), LiBF₄ salt, 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF₄) ionic liquid, and SiO₂ nanoparticles exhibited the total conductivity with significant values, reaching approximately 10^–4 S cm^–1 at −40 °C, 10^–3 S cm^–1 at 25 °C, and 10^–2 S cm^–1 at 100 °C for battery. Taking this into consideration, this Review highlights recent advancements in the development and utilization of ionic liquid electrolytes for various energy storage devices, including batteries and supercapacitors. Additionally, this review presents the bibliometric analysis of global research on ILs for energy storage devices from 2019 to 2024. By analyzing 2486 research articles from Web of Science (WOS) and Scopus databases, the study explores publication trends, citation patterns, and collaboration networks. Furthermore, the incorporation of additives, nanostructured materials, and polymer matrices has been explored to improve the mechanical and electrochemical stabilities of ionic liquid electrolytes. The study addresses the gap in understanding the practical implications of ILs in real-world energy storage systems, emphasizing the need for further research on their scalability and integration. The findings suggest that ILs hold promise for developing safer and more efficient energy storage solutions with potential applications across various industries. These insights aim to guide future research and development in the field and promote the adoption of ILs in next-generation energy technologies.

A promising technology for producing carbon-neutral fuels is fluidized-bed gasification of biomass. In combination with chemical looping gasification (CLG), the process becomes even more efficient. However, using biomass-based fuels can lead to significant ash-related issues, including bed agglomeration, fouling, deposition, slagging, and high-temperature corrosion. To address these issues, several biomass upgrading approaches are used to improve the quality of the feedstock for gasification. These approaches include torrefaction, water leaching, and blending with different additives. This study focuses on the influence of additives and biomass co-blending with low-cost biofuels on the behavior of inorganic constituents and under gasification-like conditions at 950 °C and the corresponding impact in fluidized-bed gasification. For example, blending (upgraded) barley straw with 2 wt % CaCO₃ resulted in a decrease in slag and a corresponding increase in the proportion of solid oxides. This indicates that thermal stability can be expected at operating temperatures up to 950 °C. Similarly, adding Ca/Si-rich biowaste components increases the ash softening point of herbaceous biofuels. Furthermore, the results show that adding Ca-based or woody biofuel components has a chemical effect on the fate of volatile inorganics. For example, increasing the concentration of calcium in the fuel significantly reduces the release of HCl and partially reduces the release of sulfur species, thus reducing the corrosion risk. These results contribute to the development of more efficient and cleaner biomass gasification processes for producing carbon-neutral fuels.

The sediment types in deep-sea cold seep areas are highly diverse and compositionally complex. However, their influence on the kinetic characteristics of methane hydrate formation remains unclear. In this study, we examine the formation characteristics of methane hydrates for five primary minerals presented in the region of “Site F” cold seep. The results show that the specific surface area was a crucial factor influencing the hydrate formation kinetics at a low water saturation of 30 vol %. However, due to differences in the surface properties of the sediment media, the overall rate of hydrate formation exhibited a positive but no strictly proportional correlation with the specific surface area of the sediments. Although the specific surface area of chlorite was 12–19 times that of other sediment media, its water conversion rate in the first stage was almost the same to the other sediment systems, with about 8–12% per minute. When the water saturation increased to 60%, the hydrate formation rate decreased in all the sediments, and the effect of the specific surface area became ineffective due to the different water absorption capacities of the sediments. At 500 min into the experiment, the water conversion ratio for the chlorite and albite systems was approximately 40%, while about 55% for the potassium feldspar and quartz sand systems. The comprehensive analysis of four parameters related to hydrate formation kinetics revealed that chlorite possessed the strongest water-hydrate conversion ability for methane hydrates at a water saturation of 30 vol %. In the first stage of hydrate formation, the average water conversion rate reached about 11.6% per minute. However, at a water saturation of 60%, potassium feldspar and quartz sand had higher water-hydrate conversion ability. In the first stage of hydrate formation, it was about 2.45% per minute. These findings not only enhance our understanding of the fate of deep-sea methane seepage but also provide foundational data for developing submarine gas hydrates.

Gas hydrates are a major issue during transient operations such as shut-in and start-up of subsea oil and gas production systems. In this context, the Cool-Down Time (CDT), the time that the production system takes to reach the hydrate formation region, is the most important parameter for decision-making. This work presents a systematic new method to assess one-dimensional transient multiphase flow simulations for hydrate management. This advanced method integrates the analysis of the system’s phase distribution, thermal, and pressure history, enabling an accurate determination of CDT and capturing the evolution of subcooling, the driving force for hydrate formation. The technique is also discussed in light of hydrate formation mechanisms that involve metastability and limited hydrate growth during shut-in. The concepts of different shut-in modes, CDT extension by depressurization, warming, and recovery times are described in detail. Finally, the method was applied to two typical subsea satellite production tiebacks, providing insights into potential risks and gas hydrate management strategy optimizations. The impact of this work is to offer a systematic and accurate framework for optimizing production system shutdown and start-up procedures. This approach aims to increase the reliability of gas hydrate analysis and eliminate potential conservatism, increasing the flow assurance efficiency of an oil and gas production asset.

P2-type Na_0.67Ni_0.33Mn_0.66O₂ has been widely studied as a sodium-ion battery cathode material due to its higher theoretical capacity and operating voltage. However, Na⁺/vacancy ordering, irreversible phase transition, and oxidation of lattice oxygen cause rapid capacity fading when cycled at higher voltages. Herein, we employ Ru-doping for Mn, with the objective that robust Ru 4d and O 2p covalent bonds can enhance structural stability, suppress irreversible oxygen release, and hence lead to stable capacity. A series of Ru-doped P2–Na_0.66Ni_0.33Mn_0.66–xRu_xO₂ (x = 0, 0.1, 0.2, 0.3) cathode materials are synthesized, and their electrochemical performance are analyzed in the voltage range of 2–4.5 V. Multiple voltage plateaus observed in charge/discharge profiles become smoothened with the increased Ru concentration, showing that Na⁺/vacancy ordering is effectively suppressed by Ru-doping. In situ X-ray diffraction (XRD) studies have revealed that the detrimental high-voltage P2–O2 phase transition that is normally observed for pristine composition is replaced by a more reversible P2–OP4 transition, which enhances the structural stability. The Ru-doped samples show improved cycling stability, with the Na_0.66Ni_0.33Mn_0.36Ru_0.3O₂ cathode delivering an initial capacity of 150 mAh g^–1 and a retaining capacity of 108 mAh g^–1 after 150 cycles when cycled between 2 and 4.5 V at a 0.2C rate, while the capacity of the pristine (undoped) sample dropped to 35 mAh g^–1 after 120 cycles. Also, Ru-doping enhanced the rate capability and diffusion coefficient values. This work paves new insights into the high-voltage stabilization of P2-type cathodes for sodium-ion batteries.

The recovery of CH₄ from coalbed gas (CBG) is significant for improving energy utilization and mitigating the greenhouse effect. In this study, CH₄ was separated from CBG by forming sII hydrate with 5.56 mol % 1,3-dioxolane (DIOX) solution assisted by an eco-friendly promoter sodium lauroyl glutamate (SLG). The effects of SLG concentration, initial pressure and temperature, stirring rate, and CBG composition were systematically investigated. The results revealed that the addition of SLG notably diminished the hydrate induction time and reaction durations. The presence of 500 ppm of SLG decreased the CH₄ concentration to 15.50 mol % from the initial 30.23 mol %, and the CH₄ recovery and separation factor reached 81.70% and 3.34, respectively. Comparative analyses with other eco-friendly surfactants highlighted the substantial advantages of SLG. The CH₄ concentration in the residual gas first decreased and then increased with the augmentation of the initial pressure, temperature, and stirring rate. An inverse pattern was observed in the variations of CH₄ recovery and separation factor. This indicated that there existed an optimal initial pressure, temperature, and stirring rate for CBG separation. The CH₄ content in the hydrate was increased to 91.59% after a fourth-stage enrichment, meeting the standards for the direct injection of CBG into natural gas pipelines. These findings provide valuable insights for CH₄ separation from CBG by forming sII hydrate with eco-friendly promoters.

Spark-ignition engine efficiency can be increased by co-optimizing fuel and engine. First, computational fuel design can optimize fuel molecules or composition using predictive fuel property models, e.g., for high octane numbers. Then, the engine configuration can be optimized experimentally to maximize the achievable efficiency. However, such a sequential co-optimization based on fuel properties may yield suboptimal fuels, as the fuel properties do not fully capture the complex fuel–engine interaction. Therefore, we propose the computational, simultaneous co-optimization of fuel and engine. To this end, we derive a thermodynamic engine model that predicts the engine performance as a function of fuel composition and engine configuration. We calibrate the engine model against experimental data from a single-cylinder research engine, such that new candidate fuels require no model recalibration with additional experimental engine data. As a case study, we select 10 possible alternative fuel components identified in previous studies and create 39 binary and 60 ternary fuel mixtures. The composition of each fuel mixture is then co-optimized together with the compression ratio and the intake pressure of the engine considering knock and peak pressure constraints to ensure smooth and safe engine operation. The study reveals the small esters methyl acetate and ethyl acetate as promising fuel candidates for future spark-ignition engines. For methyl-acetate-rich blends, the engine model predicts knock-free operation at compression ratios of up to 20 and boost pressures of up to 1.8 bar, rendering methyl acetate a promising alternative to methanol. Considering significant model uncertainties, however, the findings require experimental validation.