Energy & Fuels最新文献

{"title":"Engineering, Modeling, and Scale-Up of Rotary Kiln Reactors for Solid Waste Pyrolysis: A Review","authors":"Karan Sharma,&nbsp;Manishkumar D. Yadav,&nbsp;Jyeshtharaj B. Joshi","doi":"10.1021/acs.energyfuels.6c02926","DOIUrl":"https://doi.org/10.1021/acs.energyfuels.6c02926","url":null,"abstract":"<p>Therapid rise in solid waste generation and the environmentallimitations of conventional disposal methods, such as landfillingand mechanical recycling, have intensified the need for sustainablethermochemical conversion technologies such as pyrolysis. Among theavailable reactor systems, rotary kilns are particularly attractivefor large-scale applications due to their ability to continuouslyprocess heterogeneous feedstocks. However, despite their industrialmaturity in sectors such as cement and mineral processing, the designand scale-up of rotary kilns for pyrolysis remain insufficiently understoodfrom a chemical engineering perspective. This Review critically examinesindirectly heated rotary kilns for solid waste pyrolysis, focusingon reactor configurations, operational challenges, and scale-up methodologies.Key engineering aspects governing scale-up, including material selection,reaction kinetics, reactor hydrodynamics, residence time distribution(RTD), solid transport behavior, and modeling approaches, are systematicallydiscussed. Furthermore, particular emphasis is placed on the roleof kiln internals, especially lifter configurations, in controllingheat transfer, solid mixing, process intensification, and mean residencetime. Finally, a step-by-step engineering methodology for rotary kilnpyrolysis scale-up is proposed to support the development of safer,more efficient, and industrially reliable systems.</p>","PeriodicalId":35,"journal":{"name":"Energy & Fuels","volume":"40 40","pages":"21921–21960"},"PeriodicalIF":6.0,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149130668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Operational Overview of the JOGMEC-DOE-USGS Gas Production Test from Gas Hydrate on the Alaska North Slope","authors":"Yoshihiro Nakatsuka,&nbsp;Norihiro Okinaka,&nbsp;Satoshi Ohtsuki,&nbsp;Yutaro Arima,&nbsp;Yusuke Takai,&nbsp;Douglas Cismoski,&nbsp;Patrick Curley,&nbsp;Shahryar Shirzadi,&nbsp;Kyojiro Kawaguchi,&nbsp;Hitoshi Sugiyama,&nbsp;Ray Boswell,&nbsp;Timothy S. Collett","doi":"10.1021/acs.energyfuels.6c01130","DOIUrl":"https://doi.org/10.1021/acs.energyfuels.6c01130","url":null,"abstract":"<p>To understand the long-term production behavior of gashydrate,an extended-duration gas production test was conducted under the JOGMEC-DOE-USGSCollaborative Gas Hydrate R&amp;D Project in Alaska. The productiontest began in September 2023 using an electric submersible pump (ESP).During ESP operation, stepwise depressurization was followed by anextended period of continuous operation under constant bottom-holepressure (BHP). Pressure reduction below a level of ∼850 psi(∼400 psi of drawdown) was not possible due to strong surgesin gas production rate, which caused the ESP to cease functioning(“gas lock”). To prevent gas lock, continuous operationunder constant BHP was implemented at 850 psi and maintained for twomonths, with only one short-term disturbance for the safety shutdownvalve (SSV) function test. No significant variation in either gasor water production rate was detected, and production continued ata stable rate of 70 mcf/d of gas and ∼10 bbl/d of water for60 days. Although the continuous production under constant BHP providedinsights into long-term production behavior, no upward or downwardtrend in the production volume associated was observed, indicatingthat further investigation is required to understand the nature oflong-term production. Following the ESP operation, the ESP was replacedwith a jet pump (JP) to mitigate gas lock. During JP operation, BHPwas depressurized to very low levels (∼200 psi); however, thisdepressurization had only a limited effect on the formation pressure,which was assumed to be due to the presence of skin (buildup of alow-permeability fine-grained layer) associated with the sand controlsystem. Injection of chemicals was attempted to remove this skin effect,but it was unsuccessful, resulting in higher differential pressureand low productivity. The test facility was successfully operatedfor ten months from September 2023 to July 2024. Within this period,there were 315 days of operation, including 64 days of nonproductiontime due to various mechanical failures, issues relating to sand production,and replacement of the ESP with a JP. Post-test operations to retrievethe completion confirmed the ultimate failure of the aggressive sandcontrol system installed. The operational finding with respect tosand control and artificial lift will inform future gas hydrate productiontest designs.</p>","PeriodicalId":35,"journal":{"name":"Energy & Fuels","volume":"40 40","pages":"22011–22031"},"PeriodicalIF":6.0,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149124673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synergistic Ion-Bridging and Disjoining Pressure in Smart Brine EOR: A Hybrid Molecular Dynamics and Machine Learning Approach","authors":"Mohammadreza Moradi,&nbsp;Davood Ajloo,&nbsp;Jafar Mahmoudi,&nbsp;Sadegh Sadeghzadeh","doi":"10.1021/acs.energyfuels.6c03331","DOIUrl":"https://doi.org/10.1021/acs.energyfuels.6c03331","url":null,"abstract":"<p>The synergistic integration of nanotechnologyand “smartbrine” chemistry represents a complex Frontier for enhancedoil recovery (EOR), where the coupling between ion-bridging kineticsand macroscopic displacement remains a subject of rigorous investigation.This study presents a robust, computationally validated hybrid computationalframework integrating molecular dynamics (MD) simulations with machinelearning (ML) architectures to investigate the mechanistic driversof oil mobilization in siliciclastic (quartz) and carbonate (calcite)lithologies. Atomistic analysis confirms the significance of the multi-ion-bridging(MIB) mechanism, wherein divalent cations (Ca²⁺, Mg²⁺) reach up to 3.0 MPa at the three-phase contact line, contributingto a wettability alteration that reduces the contact angle by up to72% in calcite systems. A distinct “Golden Window” ofionic concentration (3.0–4.0 wt %) was identified, where interfacialpartitioning achieves an optimal thermodynamic balance. To rigorouslyanalyze the MD data set, an XGBoost predictive engine was implemented;cross-validation and feature sensitivity analyses demonstrate exceptionalpredictive capability (<em>R</em>² ≈ 0.89),identifying disjoining pressure and binding energy as primary mechanisticdrivers. Unlike traditional bulk-parameter models, this approach employsunsupervised clustering to provide a broader understanding of thegeochemical regimes governing recovery. These findings establish acomprehensive, high-precision roadmap for designing chemically engineeredrecovery processes, providing a simulation-driven, mechanically guidedapproach to estimate atomistic oil displacement (reaching η_disp ≈ 52.3% under controlled simulated conditions).</p>","PeriodicalId":35,"journal":{"name":"Energy & Fuels","volume":"40 40","pages":"22049–22070"},"PeriodicalIF":6.0,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149124825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fe-Doped ZnO/Activated Carbon Composite Derived from Oil Palm Empty Fruit Bunches for Asymmetric Supercapacitors","authors":"Lisna Rosita,&nbsp;Riyani Tri Yulianti,&nbsp;Sitti Ahmiatri Saptari,&nbsp;Jotti Karunawan,&nbsp;Rike Yudianti","doi":"10.1021/acs.energyfuels.6c02824","DOIUrl":"https://doi.org/10.1021/acs.energyfuels.6c02824","url":null,"abstract":"<p>The rapid demand for sustainable, high-performance energystoragehas accelerated the development of biomass-derived electrode materialsfor next-generation supercapacitors. However, the intrinsically lowelectrical conductivity and limited electrochemical activity of manymetal oxide electrodes remain major challenges that restrict theirpractical application. In this work, a novel Fe-doped ZnO/activatedcarbon composite derived from oil palm empty fruit bunches (Fe-ZnO/AC)was successfully synthesized via a hydrothermal method and employedas an electrode material for asymmetric supercapacitors. ZnO was selectedfor its low-cost, abundance, nontoxicity, and facile synthesis, whileFe doping was introduced to enhance electrical conductivity, charge-transferkinetics, and redox activity. Simultaneously, activated carbon derivedfrom empty fruit bunch (EFB) waste provides a conductive, porous carbonmatrix that facilitates ion diffusion and electron transport. Thisstudy highlights the synergistic integration of Fe-doped ZnO withactivated carbon, enabling simultaneous enhancement of conductivity,electrochemical performance, structural stability, and sustainabilitywithin a single-electrode system, a strategy that remains rarely exploredfor asymmetric supercapacitor applications. The Fe-ZnO/AC electrodeexhibited a high specific capacitance of 458.2 F g^–1 at 0.1 A g^–1 in a three-electrode configuration.In an asymmetric two-electrode configuration, the device deliveredspecific capacitances of 179.7 and 102.3 F g^–1 forthe coin cell and flexible cell, respectively. The corresponding energydensities reached 35.9 and 20.5 W h kg^–1 with powerdensities of 239.7 and 240.4 W kg^–1, respectively.These findings demonstrate the excellent electrochemical performance,stability, and energy storage capability of the Fe-ZnO/AC composite,highlighting its strong potential as a low-cost, sustainable, andhigh-performance electrode material for next-generation asymmetricsupercapacitors.</p>","PeriodicalId":35,"journal":{"name":"Energy & Fuels","volume":"40 40","pages":"22237–22254"},"PeriodicalIF":6.0,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149124926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MXene-Based Lithium-Ion Anodes: An Outlook on Computational Predictions and Experimental Validation","authors":"Abhinav Ernam,&nbsp;Eugenie Pranada,&nbsp;Bright Ngozichukwu,&nbsp;Abdoulaye Djire","doi":"10.1021/acs.energyfuels.6c02894","DOIUrl":"https://doi.org/10.1021/acs.energyfuels.6c02894","url":null,"abstract":"<p>First-principles studies have produced extensive predictionsofMXene-anode capacities, voltages, and diffusion barriers over thepast decade. Yet, a gap remains between these predicted metrics andthe performance observed in operating cells. We suggest that thisgap reflects not a limitation of computation itself but the absenceof a sustained feedback loop between computational and experimentalwork. Computational predictions are often communicated and cited asperformance forecasts even though they describe idealized systems(bare or uniformly terminated surfaces, equilibrium conditions, andthe absence of electrolyte, interphase, and cycling history) thatdiffer from the environment of an operating anode. Focusing on MXenelithium-ion anodes, we examine where predicted and measured capacitiesdiverge, distinguishing predictions that are inaccurate from predictionsthat are simply applied beyond the conditions they were constructedto describe. We then consider the physics that standard protocolsare not designed to capture and outline three coordinated directionsfor reconnecting computation to operating reality: coordinated theory-experimentstudies as a structural foundation, machine-learning interatomic potentialsto reach the relevant time scales, and explicit electrolyte modelingto recover interfacial energetics often omitted from vacuum-referencecalculations. We propose that the progress of MXene-anode researchbe measured by how closely computation and experiment inform eachother.</p>","PeriodicalId":35,"journal":{"name":"Energy & Fuels","volume":"40 40","pages":"21887–21894"},"PeriodicalIF":6.0,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149124936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ferrate(VI) Redox Chemistry for Energy Storage and Water Purification: A Cross-Domain Review","authors":"Jing Dong,&nbsp;Jiangmingzhu Han,&nbsp;Di Gu,&nbsp;Baohui Wang","doi":"10.1021/acs.energyfuels.6c03891","DOIUrl":"https://doi.org/10.1021/acs.energyfuels.6c03891","url":null,"abstract":"<p>Ferrate(VI), an iron-based compoundin the rare +6 oxidation state,has emerged as a multifaceted functional material for energy storageand environmental remediation. Its appeal stems from a high redoxpotential, a multielectron transfer capability, and the formationof iron(III) reduction products that are generally benign in mostwater matrices, however, in halide-containing waters, precautionsare needed as bromate or iodate formation may occur. This Review providesa comprehensive overview of the fundamental properties, synthesismethods, and most critically, the stability challenges that hinderthe practical application of Fe(VI) materials. We detail its applicationprogress in two distinct fields: as a high-capacity cathode materialin Superiron batteries, where we examine the three-electron reductionmechanism, interfacial instability, Fe(III) passivation, and shuttleeffects that limit practical performance; and as a multifunctionalreagent in water treatment, where the stepwise generation of reactiveFe(V)/Fe(IV) intermediates via oxygen-atom transfer, single-electrontransfer, and radical pathways enables concurrent oxidation, disinfection,and coagulation. A central theme of this Review is the analysis ofshared interfacial stability and reaction pathway regulation challengesacross these domains. Finally, we highlight cross-domain synergy opportunities,proposing that strategies developed in one field can inform solutionsin the other. This work aims to provide a foundational reference andforward-looking perspective for accelerating the development and deploymentof Fe(VI)-based technologies.</p>","PeriodicalId":35,"journal":{"name":"Energy & Fuels","volume":"40 40","pages":"21961–21980"},"PeriodicalIF":6.0,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149124938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ethoxy Chain Length Regulated Gemini Polymeric Surfactants for Enhanced Oil Recovery in High-Salinity Reservoirs","authors":"Zhezhe Cao,&nbsp;Yu Zhang,&nbsp;Jialin Miao,&nbsp;Jinlun Yan,&nbsp;Zi Wang,&nbsp;Longli Zhang","doi":"10.1021/acs.energyfuels.6c03547","DOIUrl":"https://doi.org/10.1021/acs.energyfuels.6c03547","url":null,"abstract":"<p>In high-salinity reservoirs, conventional polymer floodingsystemsoften suffer from severe viscosity loss, leading to reduced oil recoveryefficiency. To address this challenge, a series of Gemini surfactant-functionalizedpolymer with tunable ethoxy (EO) chain lengths (AASD-O₇, AASD-O₁₀, AASD-O₁₃, and AASD-O₁₅) were synthesized. The influences of EO chain length and ion-specificeffects of Na⁺ and Ca²⁺ on rheological properties,interfacial behavior, aggregation characteristics, emulsificationperformance, and oil displacement efficiency were systematically evaluated.Molecular dynamics simulations were employed to elucidate the effectsof EO chain length and salt ions on molecular association, salt tolerance,and oil displacement performance. The results demonstrated that EOchain length played a critical role in regulating the hydrophilic–hydrophobicbalance and salt tolerance of the polymeric surfactants. Their viscosity,surface activity, and interfacial activity exhibited a pronouncednonmonotonic dependence on EO chain length, with AASD-O₁₀ showing the optimal overall performance. Under high-salinity conditions,Na⁺ primarily enhanced hydrophobic association and chainentanglement through electrostatic shielding, whereas Ca²⁺ induced intermolecular ion-bridging networks via multipoint coordinationwith carboxyl groups, resulting in distinct ion-specific regulationmechanisms. Benefiting from the optimal balance between hydrophobicassociation and EO chain interactions, AASD-O₁₀ maintainedexcellent interfacial activity in simulated formation water, reducingthe oil–water interfacial tension to the order of 10^–3 mN/m and forming stable oil-in-water (O/W) emulsions with a heavy-oilviscosity reduction rate over 99%. Microscopic displacement experimentsdemonstrated that all AASD polymeric surfactants outperformed conventionalpartially hydrolyzed polyacrylamide (HPAM), with AASD-O₁₀ achieving the highest oil recovery of 76.67%, which was 22.37 percentagepoints higher than HPAM. Molecular dynamics simulations further revealedthe intrinsic relationships among EO chain length, ion-specific interactions,molecular association structures, and macroscopic oil displacementperformance. These findings provide new insights into the design ofsalt-tolerant polymeric surfactants and offer a promising strategyfor enhanced heavy-oil recovery in high-salinity reservoirs.</p>","PeriodicalId":35,"journal":{"name":"Energy & Fuels","volume":"40 40","pages":"22071–22081"},"PeriodicalIF":6.0,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149125003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated Geological Hydrogen Storage in Depleted Gas Reservoirs: A Techno-Economic Assessment","authors":"Mohamad Mohamadi-Baghmolaei,&nbsp;Abdollah Hajizadeh,&nbsp;Dru Heagle","doi":"10.1021/acs.energyfuels.6c03367","DOIUrl":"https://doi.org/10.1021/acs.energyfuels.6c03367","url":null,"abstract":"<p>Hydrogen storage is essential for the global transitionto cleanand sustainable energy, as it can balance variable renewable power,improve energy security, and support a reliable hydrogen supply. Amonglarge-scale storage options, underground hydrogen storage in depletedgas reservoirs is a promising solution due to its high capacity andthe potential to leverage existing infrastructure. In this study,an integrated subsurface–surface techno-economic frameworkwas developed for the Dawn Hub depleted gas reservoir in Ontario,Canada. The framework models hydrogen blending with natural gas atthe surface, reservoir injection and withdrawal, pressure swing adsorption(PSA)-based hydrogen separation, and recompression for delivery. Atwo-zone reservoir model, representing working gas and cushion gaswith interzone mixing, was used to capture cyclic storage behaviorand its effect on hydrogen recovery and gas composition. The subsurfaceand surface models were validated using field, industrial, and literaturedata, providing a reliable basis for cost assessment. Three infrastructurecases were studied: Scenario 1, injection, separation, and recompressiononly; Scenario 2, Scenario 1 plus hydrogen transport; and Scenario3, Scenario 2 plus natural gas transport. The total levelized costof hydrogen (LCOH) decreased with plant scale, with Scenario 1 andScenario 2 approaching ∼9 USD/kg H₂ at large scale,while Scenario 3 remained higher at ∼12–13 USD/kg H₂. The lowest median LCOH was obtained at 15–20 mol% H₂ injection, reaching ∼9.67–9.68 USD/kgH₂ in Scenario 1. When the hydrogen feedstock cost wasexcluded, the cost trend became more clearly decreasing with increasingH₂ concentration, and the facility-driven LCOH droppedfrom about 2.1 to 0.45 USD/kg H₂ in Scenario 1, 3.1 to0.66 USD/kg H₂ in Scenario 2, and 14.5 to 1.4 USD/kg H₂ in Scenario 3 between 5 and 50 mol % H₂. Overall,the framework provides a practical basis for generating cost curvesand supporting design and operational decisions for underground hydrogenstorage in depleted gas reservoirs.</p>","PeriodicalId":35,"journal":{"name":"Energy & Fuels","volume":"40 40","pages":"22198–22227"},"PeriodicalIF":6.0,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149124971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ex-Situ CO2 Mineralization: Bridging Laboratory Science and Industrial Reality. Part I: Thermodynamic Foundations, Kinetic Barriers, and Engineering Pathways to Scale","authors":"Babak Fayyaz-Najafi,&nbsp;Cesar Ovalles","doi":"10.1021/acs.energyfuels.6c03945","DOIUrl":"https://doi.org/10.1021/acs.energyfuels.6c03945","url":null,"abstract":"<p>Ex-situCO₂ mineralization offers permanentcarbon storageby reacting CO₂ with alkaline solids to form thermodynamicallystable carbonate minerals. Unlike geological storage, which requireslong-term subsurface monitoring, mineralized carbon in stable carbonateproducts remains fixed for &gt;10,000 years with negligible leakagerisk,although product-phase and carbon-accounting verification remain necessary.This review (Part I) examines the pathway from thermodynamic foundationsthrough reaction kinetics and activation strategies to reactor engineering,scale-up, and the current technology landscape. Carbonation is thermodynamicallyfavorable (Δ<em>G</em>° = −20 to −130kJ/mol CO₂), but practical rates depend strongly on mineralogy,particle history, reaction pathway, and transport regime. Reactivecalcium-rich industrial residues can carbonate under comparativelymild conditions, whereas crystalline magnesium silicates generallyrequire grinding, thermal or chemical activation, additives, or elevatedtemperature and CO₂ pressure. Process-engineering approachesevaluated include direct gas–solid carbonation, aqueous slurrysystems, indirect multistep routes, and intensified contactors. Thetechnology landscape includes commercial residue-based operators suchas CarbonFree, Fortera, and Neustark; demonstration ventures suchas MCi Carbon, Blue Planet, and Paebbl; and emerging mine-integratedprojects such as Canada Nickel’s Crawford development. Theevidence indicates that feedstock-specific kinetics, activation energydemand, solids handling, product markets, and verified delivered capacity─notthermodynamic favorability alone─govern scale-up. Quantitativetechno-economic and life-cycle assessments are developed in the companionpaper (Part II).</p>","PeriodicalId":35,"journal":{"name":"Energy & Fuels","volume":"40 40","pages":"21981–22010"},"PeriodicalIF":6.0,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149124775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MILD Combustion of Partially Cracked Ammonia: Effects of Fuel Cracking, Steam Dilution, and Oxidizer Preheating","authors":"Ehab Sabry Rashed,&nbsp;Saleh Abo-Elfadl,&nbsp;Eslam Reda Lotfy,&nbsp;Shinsuke Mori,&nbsp;Hamdy Hassan","doi":"10.1021/acs.energyfuels.6c03971","DOIUrl":"https://doi.org/10.1021/acs.energyfuels.6c03971","url":null,"abstract":"<p>Ammoniais a promising carbon-free energy carrier, and growingconcerns over fossil fuel supply security further motivate its adoption;however, its application in combustion systems remains constrainedby low reactivity and high NO_<em>x</em> emissions.While ammonia cracking enhances fuel reactivity and Moderate or IntenseLow-oxygen Dilution (MILD) combustion enables low-emission operation,the reactive structure and ignition behavior of partially crackedammonia under MILD conditions remain insufficiently understood, particularlywith respect to oxidizer steam dilution and preheating. This studypresents a validated, three-dimensional RANS-based CFD investigationof a MILD combustion furnace using detailed chemical kinetics (CEU-NH₃ mechanism with dynamic reduction). A total of 54 operatingconditions are examined by systematically varying the cracking ratio(γ = 0.0–0.8), steam-to-air ratio (SAR = 0.0–0.3),and oxidizer preheating temperature (300–700 K) at fixed equivalenceratio and thermal power. The results show that no self-sustained combustionis achieved at very low cracking ratios (γ = 0.0–0.1),consistent with ignition delay times reported in the literature thatare an order of magnitude longer than at γ = 0.2, due to insufficientfuel reactivity. For ignited cases, increasing γ enhances reactivityand heat release up to γ ≈ 0.4–0.5, leading toupstream ignition, higher peak temperatures, and more compact reactionzones, while further increases cause thermal saturation due to NH₃ depletion and dilution effects. Steam dilution broadens thereaction zone, improves temperature uniformity, and promotes distributedMILD-like combustion; however, at high cracking ratios (γ ≥0.6), steam is found to promote NO formation, despite its thermaldiluent effect. All examined cases fall within the MILD-like regimebased on reaction zone inlet conditions, a classification confirmedto be robust across a 6-fold variation in the reaction zone boundarythreshold. These findings clarify the coupled roles of cracking, steamdilution, and preheating in controlling ignition, distributed reactioncharacteristics, and NO_<em>x</em> emissions inpartially cracked ammonia MILD combustion.</p>","PeriodicalId":35,"journal":{"name":"Energy & Fuels","volume":"40 40","pages":"22294–22312"},"PeriodicalIF":6.0,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149124972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}