Energy & Fuels最新文献

Gashydrate formation in oil and gas flowlines can result in severeoperational, economic, and safety hazards. Therefore, advanced knowledgeof hydrate nucleation and growth kinetics is a dire need in operationswherein thermodynamic conditions are favorable for gas hydrates. Thisreview delivers an account of the research efforts put forth towardinnovative technologies and instrumental advancements with specialemphasis on their governing mechanism and methods to understand therisk of hydrate formation in subsea multiphase oil/gas pipelines.Further, a detailed section on the effect of underinhibition on hydrateplugging potential has been included due to its significance in improvingthe economic feasibility of offshore gas fields, particularly thosein deepwater and/or with long subsea tiebacks. Moreover, to understandhydrate plugging at pilot scale and in actual subsea conditions, wesummarized the state of the art in hydrate flow loops (including thosewith integrated jumpers) and their advancements in terms of instrumentation,development of new hydrate models, and integrated flow assurance framework,which eventually improve the prediction, prevention, and managementof hydrates in flow assurance.

Aqueous zinc-ion batteries (AZIBs)offer considerable potentialfor sustainable energy storage; however, dendritic growth and interfacialparasitic reactions severely hinder the reversibility of zinc anodes.Herein, we report a multifunctional hybrid protective interphase (PVA/ZIF-8@Zn)constructed by combining poly(vinyl alcohol) (PVA) with zeolitic imidazolateframework-8 (ZIF-8). PVA molecules regulate the Zn²⁺ solvationstructure through hydroxyl coordination, while ZIF-8 provides zincaffinity via its nitrogen sites, guiding uniform Zn²⁺ depositionand suppressing dendrite growth. Moreover, the synergistic combinationof PVA’s intrinsic flexibility and ZIF-8’s structuralrigidity suppresses parasitic side reactions and effectively accommodatesvolumetric fluctuations of the zinc anode during cycling. Consequently,the PVA/ZIF-8@Zn anode exhibits exceptional stability, achieving over2400 h of reversible cycling in symmetric cells at 1 mA cm^–2 and 1 mAh cm^–2. Furthermore, the assembled fullcells deliver a discharge capacity of 79 mAh g^–1 after 2000 cycles at 1 A g^–1, corresponding toa capacity retention of 75%. This work provides a feasible designstrategy for constructing “rigidity-flexibility synergistic”interfacial layers for high-performance AZIBs.

The integration of CO₂ capture and utilizationis apromising strategy for carbon management. In CaO-based systems, CaOcan act as a CO₂ sorbent during carbonation and as reversewater–gas shift (RWGS) catalyst during regeneration. However,the interaction between CaCO₃ decomposition and catalyticreactivity remains poorly understood. In this work, the RWGS activityof CaO was investigated under conditions relevant to desorption-enhancedreverse water–gas shift (DERWGS). Conventional power-law kineticswere unable to reproduce the experimental results, whereas the inclusionof an H₂O inhibition term accurately described the observedbehavior and yielded physically meaningful reaction orders. The kineticanalysis identified H₂O inhibition as a key factor governingRWGS activity. Combined analysis of RWGS and calcination kineticsreveals that the overall process arises from the coupling betweenCO₂ release during calcination and its catalytic conversionon CaO. Cycling experiments further show that catalyst deactivationfollows the decay in CO₂ carrying capacity, suggestinga common structural origin. These findings provide a kinetic frameworkfor describing DERWGS as a dynamically evolving system governed bythe interplay between solid-state transformation and catalytic surfaceprocesses.

To increase the combustion calorificvalue, reduce the greenhouseeffect of CO₂, and prevent corrosion to pipelines, impuritygases such as CO₂ and N₂ in biogas must be effectivelyremoved. This study investigates the effects of leucine (Leu) on thekinetics and gas separation efficiency of synthesized ternary (CH₄/CO₂/N₂) gas hydrate formation. Theexperimental work involved monitoring pressure drop, gas consumption,CH₄ recovery, CO₂ capture, and separation factorunder various conditions of pressure, temperature, and Leu concentration.Advanced characterization techniques, including powder X-ray diffraction,Raman spectroscopy, and Cryo-SEM, were employed to analyze hydratestructure, cage occupancy, and crystal morphology. The key findingsindicate that 0.5 wt % Leu optimally promotes formation kinetics andenhances gas separation at medium pressures and high supercooling.A trade-off relationship between CH₄ recovery and CO₂ capture was observed, influenced by Leu concentration andthe degree of supercooling. Structural analysis confirmed the formationof sI hydrate with co-occupancy of gas molecules, while morphologicalstudies showed that increased Leu concentration leads to a denser,more uniform crystal arrangement. The promotion mechanism is attributedto the adsorption of Leu’s hydrophobic groups at the hydrateinterface, which enhances gas–liquid mass transfer and facilitatesnucleation and growth, thereby improving overall kinetic performanceand separation effectiveness.

This study develops a corridor-specific techno-economic frameworkfor LOHC-based hydrogen export from Australia to Japan and appliesit to four representative carrier systems: toluene/methylcyclohexane(TOL/MCH), dibenzyltoluene/perhydrodibenzyltoluene (H₀-DBT/H₁₈-DBT), N-ethylcarbazole/perhydro-N-ethylcarbazole (H₀-NEC/H₁₂-NEC),and benzene/cyclohexane (BZ/CH). The framework integrates carrier-specificprocess simulation, maritime logistics, regional cost assumptions,heat-supply options, and deployability factors within a unified hydrogen-to-hydrogensupply chain boundary. The results show that hydrogen production is the dominant cost driver, while carrier choice strongly affects salablehydrogen output, dehydrogenation energy demand, and noncost feasibility.Under the base-case configuration, in which dehydrogenation heat issupplied by combusting a portion of the produced hydrogen, the deliveredlevelized cost of hydrogen (LC_H2) ranges from 16.42 to24.99 A$/kg-H₂, with BZ/CH achieving the lowest cost (16.42A$/kg-H₂) while TOL/MCH represents the highest-cost option(24.99 A$/kg-H₂). An alternative biomass combustion heatsource lowers LC_H2 for all carriers and changes the rankingby making TOL/MCH the second-lowest-cost option (14.30 A$/kg-H₂), while BZ/CH remains the lowest-cost system (12.41 A$/kg-H₂) and H₀-NEC/H₁₂-NEC becomes the highest-costoption (19.05 A$/kg-H₂). H₀-DBT/H₁₈-DBT provides a more balanced combination of cost, technical maturity,safety, and commercial deployability.

This study proposes a novel strategy to achieve ammonia-freedirectNO decomposition in cement pyroprocessing by utilizing Cu-doped modifiedcoal fly ash (Cu-MCFA) as a consumable catalytic additive. This studyaims to clarify the synergistic effect between the Fe sites withinMCFA and the supported Cu species toward direct NO decomposition.The findings indicate that alkaline–acid modification constructsa mesoporous conduit and exposes intrinsic Fe³⁺ activesites, while the introduction of Cu alters NO activation. Specifically,Cu doping generates binuclear [Cu–O–Cu]²⁺ dimers and abundant surface oxygen vacancies. These dimeric centersexecute the complete cleavage of the N–O bond via a Langmuir–Hinshelwoodbimolecular coupling mechanism, achieving 89% NO conversion and 99%N₂ selectivity. In situ DRIFTS revealed that the undopedMCFA can form stable bidentate nitrates, the robust reducibility ofCu sites drives rapid oxygen desorption and averts nitrate accumulation.Furthermore, while incomplete NO decomposition over unpromoted sitesleads to massive N₂O byproduct emissions, the Cu-drivenredox cycle suppresses this pathway. Importantly, leveraging the compositionalhomology between the CFA substrate and cement raw materials, the exhaustedcatalyst seamlessly undergoes in situ calcination into cement clinker.This research reveals the potential of utilizing industrial solidwaste for efficient denitration, providing a viable pathway for collaborativeresource utilization in cement-kiln systems and other energy-intensiveindustries.

Deep and ultradeep oil reservoirs, characterized by hightemperatures,high pressures, and strong formation heterogeneity, have emerged asthe primary battleground for crude oil production. However, conventionalplugging materials, such as hydrogels and solid particles, face significantchallenges in effectively operating within such reservoirs. In thiswork, a novel epoxy thermosetting plugging resin with good injectability,long gelation time, high strength, and excellent sealing performanceis designed and developed, which is composed of epoxy prepolymer diglycidylether of bisphenol A, curing agent 4,4′-((methylenebis(4,1-phenylene))bis(azanediyl))bis(4-(furan-2-yl)butan-2-one),and diluent butyl glycidyl ether (BGE). BGE is selected to reducethe initial system viscosity while preserving its mechanical propertiesafter solidification. Upon the addition of 20% BGE, the viscositysignificantly decreases from 52,900 mPa·s to 2680 mPa·s,while the compressive strength after curing remains 74.4 MPa, andthis addition exerts only a small influence on the gelation process.The gelation time at 150 °C reaches 7.8 h, and the cured productexhibited a 5% mass-loss temperature of 300 °C under the TGAcondition. Simulated plugging experiment results show that this systemexhibits substantially improved injectability. The breakthrough pressurereaches a value exceeding 12 MPa at 120 °C. Notably, followingwater breakthrough, the inlet pressure does not undergo a rapid reductionto 0 MPa; rather, it experiences a slight decrease to a constant valuein excess of 11 MPa. The improved injectability, long gelation time,high-temperature resistance, and exceptional mechanical properties,as well as the excellent plugging capability, make this epoxy resina promising novel plugging material for deep and ultradeep reservoirs.

Elucidating the nucleation kinetics of structure II (sII)hydratesin authentic marine clay environments is essential for gas hydrateresource evaluation and safe exploitation in the South China Sea.Using in-situ marine clay sediments as porous media, we conductedhigh-pressure visual hydrate formation experiments at five loadinggradients (0–10 g) coupled with multi-scale characterizations,to quantify variations in induction time and gas conversion rate.Marine clay exhibits a pronounced dual concentration-dependent effect:moderate dosage (≤ 2 g) reduces induction time by 192.67 mincompared with the blank system, while excessive clay prolongs it by11.67 min relative to the optimal group. The gas conversion rate followsa non-monotonic trend, peaking at 2–5 g and declining sharplyat 10 g. Dispersed clay particles at low concentrations furnish abundantheterogeneous nucleation sites to lower the energy barrier, whereasexcess clay triggers aggregation and pore clogging, elevates masstransfer resistance, and inhibits nucleation. This work clarifiesthe concentration-dependent nucleation mechanism of sII hydrates innatural marine sediments, providing a reliable experimental basisfor hydrate development.

This study presents a process-level techno-economic analysisofsolidified natural gas (SNG) production via clathrate hydrate formation,evaluating three configurations ─ pure methane (sI), methane-THF(sII), and methane-1,3-dioxolane (sII) ─ at a feed capacityof 0.13 MMTPA. Process simulations were developed in Aspen HYSYS V15using the Twu–Peng–Robinson equation of state, withcapital and operating costs estimated using the Towler and Sinnottframework. Sensitivity analyses examined methane inlet pressure (atmosphericvs 45 bar) and refrigerant choice (propane vs ammonia). Literature-derivedmethane conversions of 10.0% for the pure-methane case and 42.0% forthe promoted cases were specified in the conversion-reactor model.The pure methane case yielded a process-cost levelized cost of storage(LCOS) of $0.794/kg under atmospheric conditions ─ uncompetitiveagainst LNG ($0.169–$0.434/kg) and CNG ($0.175/kg). Promoter-assistedconfigurations achieved $0.107–$0.217/kg excluding raw materialcost, competitive with LNG under favorable conditions. However, thepromoter makeup requirement of 15209 kg/h ─ the stoichiometricquantity incorporated into the sII lattice and leaving with the solidproduct ─ generates an annual raw material cost of $184M, raisingLCOS to $3.39–3.50/kg across all promoted cases regardlessof operating conditions. Because this promoter is a structural constituentof the product rather than a recoverable stream, it cannot be reducedby in-process recovery. First-stage methane compression dominatescapital and operating costs; colocation with high-pressure gas infrastructurereduces LCOS by 44–59%. These findings indicate that thermodynamicpromoters confer no net economic benefit at industrial scale, andthat the unpromoted pathway is the more tractable route to competitiveSNG, contingent on improved conversion.

Depressurization is generally regarded as the most practicalmethodfor extracting marine natural gas hydrates. However, conventionalsingle-stage depressurization often leads to rapid temperature dropsand excessive water production, which can increase the risk of formationcollapse. Therefore, considering both safety and economic efficiency,this study established a numerical model based on geological datafrom the SH7 site in the Shenhu area of the South China Sea and designedmultiple depressurization strategies. The dynamic gas production behaviorunder both single-stage and staged depressurization schemes over a1000 day period was investigated. The depressurization amplitude coefficient(C_DA) and the depressurization returnratio (R_DR) are introduced to quantifythe trade-off between production efficiency and depressurization risks.The results indicate that although a larger depressurization in single-stagedepressurization enhances early gas production and improves the gas-to-waterratio, it also results in higher water production and reduced long-termrecovery. When the initial depressurization and production timingare properly configured, the staged depressurization strategy caneffectively stimulate reservoir potential, increasing cumulative gasproduction by approximately 18.6% compared with conventional single-stagedepressurization. Furthermore, staged strategies achieve higher gasproduction rates while maintaining a lower C_DA, demonstrating a favorable balance between economic benefitand operational safety.