An electrical heating fluidized-bed thermal energy storage (EH-FB-TES) system is proposed for integration with a coal-fired power plant (CFPP) for deep peak shaving (DPS) due to its high energy storage density and extensive heat exchange performance. The primary objective of this study is to evaluate the thermodynamic performance and economic feasibility of the integrated EH-FB-TES system, specifically focusing on identifying the optimal coupling and heat recovery strategies for enhanced deep peak shaving performance. Since EH-FB-TES uses air flow for fluidization in the heating storage process, its coupling with the CFPP differs from other TES technologies, and the associated thermodynamic performance and cost are thereby analyzed. The results show that, in EH-FB-TES, the heat release efficiency is predominantly constrained by thermal losses. To increase the energy utilization efficiency, a two-stage heat recovery strategy is proposed to release the stored energy in the integration. The first stage is to heat up the feedwater extracted from the deaerator and the second one is to heat up the condensate water. The analyses also show that the selection of reinjection positions for the heated medium from EH-FB-TES greatly influences the system performance. Returning the stored thermal energy to heat up feedwater can effectively increase the output of the unit, while directly generating steam can be beneficial for coal saving. The integrated system achieves a maximum equivalent round-trip efficiency of 32.9% under 20 MW/800 degrees C conditions. An economic analysis reveals that, compared with other energy storage methods, EH-FB-TES can realize a relatively high energy storage density with a rather low cost. Under the present DPS compensation policy, for a 315 MW subcritical CFPP integrated with a 50 MW EH-FB-TES system, when heat storage is 8 h, heat release is 4 h per day, and the plant operates 100 days per year, the estimated static and dynamic payback periods are 3.06 years and 3.67 years, respectively. The integration of CFPP with EH-FB-TES could be promising for meeting DSP requirements.

Recently, environmental issues caused by nitrogen oxide (NOx) and carbon dioxide (CO2) emissions have gained widespread attention. Pressurized Oxy-Fuel Fluidized Bed Combustion (POFBC) enables low-carbon combustion for industry such as coal-fired power plants and realizes the cascaded utilization of pressure, assisting carbon capture and reducing NOx emissions. However, POFBC is an extremely complex physical and chemical process, and the influence of operating parameters on flow characteristics, combustion and final product distribution remains unclear, posing substantial challenges to the scale-up design and long-term operation of POFBC. Numerical simulation based on Computational Fluid Dynamics (CFD) has become important for researching POFBC. CFD aids reveal how operating parameters such as pressure influence the mechanisms, compensating for the limitations of experimental studies and the high costs due to trial-and-error experiments. CFD modeling setups have great effect on the accuracy and validity of numerical simulations, the research of which can provide references for more accurate and efficient CFD calculations and field experiments. This paper provides a detailed review of the developments in the numerical simulations and industrial application of POFBC technology. Also, the global scholars who have made significant contributions to POFBC are summarized. Coupled three-dimensional mathematical models of multiphase flow, heat transfer, chemical reactions, gas-solid flow and pollutant formation in POFBC are comprehensively analyzed and compared. The applicability, sensitivity and accuracy of these models are elucidated. This work provides suitable modelling setups for CFD numerical simulations, offering plentiful references for improving operating parameters and physical structures of POFBC to help achieve carbon neutrality.

Slagging and fouling on the heating surfaces significantly constrain the operational safety and thermal efficiency of boilers under flexible operation and fuel diversification. Monitoring is the essential prerequisite for preventing and controlling these processes. This paper provides a comprehensive review of advancements in the slagging and fouling monitoring by analyzing the commonalities of these processes with a classification method rooted in the evolution of deposits development. The monitoring methods are categorized into four kinds: precursor tracking, macroscopic diagnosis, operational parameter response, and mechanical response identification. The principles, implementation, and current research status of the methods are introduced. The advantages, limitations, and improvement pathways of the methods are discussed in four aspects of fidelity, promptness, robustness, and viability. In addition, the recent advancement in the associated technologies with integration of artificial intelligence (AI) is summarized, highlighting how AI-enhanced monitoring methods can improve the performance through multi-variable decoupling and non-linear feature extraction. In the last, future research priorities concerning mechanistic refinement, multi-source fusion, and mechanism-driven AI enhancement on the monitoring are proposed.

ABSTRACT Narrowband multiple‐resonance thermally activated delayed fluorescence (MR‐TADF) emitters are pivotal for wide‐color‐gamut displays, yet they often encounter an inherent trade‐off between emission redshift and spectral broadening. In this study, we present a molecular design strategy that incorporates antiaromatic four‐membered rings into a boron‐ and nitrogen‐embedded MR framework to achieve aromaticity localization. This approach enhances the aromaticity localization within the MR skeleton, effectively suppressing vibrational coupling and narrowing the emission spectrum, while simultaneously extending the π‐conjugation to induce a bathochromic shift—thereby counteracting the typical broadening that accompanies redshift. Relative to the DABNA‐1 parent molecule, the designed emitter exhibits a substantially redshifted emission maximum from 460 to 523 nm, along with a narrowed full‐width at half‐maximum (FWHM) from 27 to 16 nm. The corresponding organic light‐emitting diode (OLED) achieves a narrow FWHM of 21.5 nm with CIE coordinates of (0.26, 0.70), a maximum external quantum efficiency (EQE max ) of 36.1%, and a significantly low efficiency roll‐off. Remarkably, the device demonstrates superior operational stability with an LT90 lifetime of 1469 h at an initial luminance of 1000 cd m −2 . This work establishes a novel paradigm in molecular design for realizing long‐wavelength MR‐TADF emitters that concurrently achieve high color purity and excellent electroluminescence performance.

The effects of incoming flow mixing uniformity and co-flow on the flashback of laminar syngas/air jet flames for a micro-mixing burner were experimentally and numerically studied. The results showed that at the onset of flashback, induced by diffusional-thermal instability, flames possessed a pyramid structure and with rotation at a relatively small equivalent ratio. The mixing uniformity did not affect the flashback mechanism. At a small phi, the flashback velocity (UFB) at different mixing modes were nearly the same. While at a high phi, UFB was larger at a poorer fuel/air mixing. With a hot co-flow, UFB increased and more rapidly changed with phi. Moreover, the lean limit decreased and flashback propensity increased. Besides, UFB was less sensitive to mixing uniformity with hot co-flow. In this case, the incoming flow mixing effect was obvious but less important than the change of SG caused by high temperature mixing of co-flow.

Ultrahigh-definition displays urgently demand narrowband emitters with ideal Gaussian emission profiles. Multiple resonance (MR) systems are highly competitive yet face a formidable bottleneck: The minimum achievable emission linewidth has become an elusive threshold that cannot be further broken for existing systems. Here, the study proposes a pioneering strategy via intramolecular hydrogen bond construction to break the spectral limit of indolocarbazole (ICz) emitters and develops rotary chiral ICz-fused enantiomeric isomers. This chirality-modified ICz emitter concurrently achieves an emissive peak of 466 nanometers, a full width at half maximum (FWHM) of 56 milli-electron volts, and a suppressed shoulder peak in dilute toluene, impressively achieving the narrowest emission among all reported circularly polarized MR emitters to date. The corresponding electroluminescence device exhibits ultrapure deep-blue emission with a peak wavelength of 469 nanometers and an FWHM of 15 nanometers, as well as high maximum external quantum efficiency of 32.5% with minimal roll-off (20.6% at 10,000 candelas per square meter).

As a revolutionary display technology, organic light-emitting diodes (OLEDs) have achieved remarkable technological progress and commercial success in recent years. However, despite years of intensive research, high-efficiency deep-blue OLEDs with a long device lifetime remain elusive. Sensitized fluorescence, in which phosphorescence or thermally activated delayed fluorescence sensitizers are combined with narrowband fluorophores as terminal emitters, has emerged as a promising solution. This synergistic strategy holds great potential for thermodynamically and kinetically stabilizing deep-blue devices, alongside realizing unity exciton utilization efficiency and narrowband electroluminescence. Here we highlight recent advancements in the molecular design of sensitizers and narrowband emitters, as well as the optimization of their combination, for applications in deep-blue sensitized fluorescent devices. We also identify key challenges and outline pathways for the future commercialization of highly efficient and stable blue OLEDs that go beyond conventional fluorescence. This Review discusses recent advances in sensitized fluorescence emitters for deep-blue organic light-emitting diodes, reviewing progress in molecular design and device performance as well as key remaining challenges.

Ammonia, recognized as a carbon-free and hydrogen-rich fuel, is receiving growing attention as part of global carbon-reduction strategies. Co-firing ammonia in coal-fired equipment offers a practical pathway to lower CO2 emissions from existing units. This study quantifies how ammonia blending ratio, oxygen mole fraction, and swirl number affect the ignition of ammonia-coal co-firing flames using a Hencken burner. Unlike most prior studies, we employed a high pulverized coal loading of 0.75 kg & sdot;m3 in the primary air, representative of boiler conditions and examined three particle size fractions with dominant sizes of 48---75 mu m, 75---96 mu m, and 96---120 mu m. Visible light image and its RGB channel resolved four characteristic regions of the flame: preheating, gaseous ignition/combustion, primary combustion, and burnout zones. Experimental results demonstrated that ammonia significantly influenced coal ignition characteristics by altering flame morphology and ignition delay times. Under non-swirling conditions (S = 0), increasing the ammonia blending ratio from 0 % to 30 % produced a clear increase in ignition delay time, attributed primarily to preferential O2 consumption by NH3 oxidation. Raising the swirl number from 0 to 0.78 substantially shortened the ignition delay by approximately 75---78 % due to enhanced turbulent mixing and the formation of a central recirculation zone. Increasing the oxygen mole fraction in the hot flue gas from 13.8 % to 31.7 % further reduced the delay by about 20 %. A stronger swirling field also promoted interactions between NH3 oxidation intermediates and coal volatiles, which improved flame stability and combustion efficiency. This study provides insights into the coupling effects of swirl and ammonia blending, thereby offering practical guidance for the industrial-scale implementation of ammonia-coal co-firing technologies aimed at achieving efficient combustion and substantial carbon emission reductions.

To enhance the capability of deep participation in electricity load regulation and absorb curtailed renewable energy, a regulation strategy for coal-fired power units integrated with multi-time-scale energy storage is proposed, addressing the high costs of single energy storage solutions. A 660 MW Circulating Fluidized Bed (CFB) power plant integrated with Solid Oxide Electrolysis Cells (SOEC) for hydrogen storage, Thermal Energy Storage (TES), and Battery Energy Storage Systems (BESS) forms the core unit for grid stability and load balancing. The system is modeled in Aspen Plus, with thermodynamic and economic models developed to evaluate performance, storage capacity, response time, efficiency, and economic feasibility. Results show that BESS is optimal for shortterm, high-efficiency operations, SOEC excels in long-duration storage with a Levelized Cost of Electricity (LCOE) of 3.09 CNY/kWh, and TES offers a cost-effective medium-term solution with an LCOE of 0.72 CNY/kWh, considering renewable energy pricing. As storage duration extends to two weeks, annual energy losses increase to 3.00% for TES and 5.45% for BESS, raising their LCOE above that of SOEC, whose storage loss remains relatively stable under continuous hydrogen export. By leveraging each technology's strengths, the strategy decomposes net grid load into time-scale components, aligning them with responsive storage to ensure dynamic grid balancing and enhance renewable integration. A case study of the Shanxi power grid shows the coordinated strategy achieves short payback through efficient multi-scale energy recovery, especially when curtailed renewable energy pricing is negligible, despite SOEC's higher initial costs. The hydrogen-oriented mode currently offers superior economics, while both electricity- and hydrogen-oriented modes are expected to be viable for coal units, including both CFB and conventional coal-fired plants, as SOEC technology matures, confirming the strategy's competitiveness and practical potential for multi-time-scale energy storage regulation.

Conventional energy sources,including coal,oil,and natural gas,remain the primary energy supply for the great majority of countries around the world.While being used for power genera-tion,heating,transportation,and other industries,they serve as the main source of global carbon dioxide(CO2)emissions.Reduc-ing carbon emissions from the utilization of conventional energies by achieving low-carbon transformation for conventional energies(LCT4CE)is crucial for carbon neutrality.

To mitigate carbon emissions from coal-fired power plants while ensuring operational stability, this study numerically investigates the combustion behaviors and pollutant emissions of a 660 MW corner-tangentially-fired boiler under ammonia-coal co-firing conditions (0-60% calorific value ratio) at maximum continuous rating (BMCR). The results show that furnace combustion temperature first increases and then decreases with rising ammonia blending ratio (calorific basis), accompanied by a downward-shifted flame center and concentrated heat absorption in the lower furnace. Notably, 40% ammonia blending achieves the most significant CO2 emission reduction among all ratios, with CO emissions maintained at a manageable level after an initial peak at 10% blending. For NOx emissions, a peak at 10% blending is induced by localized high-temperature zones and primary combustion zone oxygen depletion; however, beyond 20% blending, NOx emissions fall below pure coal combustion levels, driven by reduced thermal NOx formation and enhanced NOx reduction by ammonia-derived nitrogenous intermediates. At 40% blending, unburned ammonia slip remains moderate, avoiding tail flue corrosion and ash deposition risks. This study identifies 40% ammonia co-firing as the optimal full-load condition for the boiler, realizing prominent carbon reduction while balancing combustion stability, pollutant control, and operational safety, and provides valuable engineering insights for ammonia-co-firing retrofit and efficient operation of coal-fired boilers.

In this study, Al-doped Li6.1La3Zr2Al0.3O12 (Al-LLZO) was synthesized via spray evaporation method, followed by calcination and hot-press sintering to produce solid-state electrolyte pellets. Characterization was performed via phase Doppler particle analyzer (PDPA), laser particle size analyzer (LPA), cold field emission scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), and distribution of relaxation times (DRT) analysis. The research examined the initial droplet size distribution from atomization, the effect of spray evaporation conditions on the morphology and particle size distribution of both the spray evaporation and calcination powders, and the impact of calcination powder size on electrolyte pellet ionic conductivity. Results shown that spray evaporation powder exhibited a bimodal particle size distribution. The morphology of the spray evaporation powder was dependent on the evaporation temperature and the relative concentration of the precursor solution: higher evaporation temperatures and higher precursor solution concentrations promoted fractured spherical shells, while lower values yielded spherical particles. Calcination powder displayed distinct sintering necks and a unimodal particle size distribution, with larger particles obtained at higher evaporation temperatures and precursor solution concentrations. Increasing calcination powder size enlarged the grain size in the hot-press sintered pellets. At consistent relative density, this grain growth selectively reduced grain boundary resistance while leaving bulk resistance unaffected, thereby enhancing overall ionic conductivity. A maximum ionic conductivity of 2.09 x 10(-4) S/cm was achieved at evaporation temperature of 900 degrees C and a relative precursor solution concentration of 0.9, within the typical range reported for cubic Al-LLZO.

Load changes of a circulating fluidized bed (CFB) boiler reconstruct the internal gas-solids flow structure, thereby altering heat transfer and combustion efficiency. To elucidate the dynamic response characteristics of the gas-solids flow in CFB, this study systematically investigates the effects of step changes in superficial gas velocity and solids inventory on solids holdup in the riser and its response behavior, combining cold-state experiments with Computational Particle Fluid Dynamics (CPFD) simulations. The reliability of CPFD for transient processes, largely overlooked in previous studies, was evaluated. Under step changes in superficial gas velocity, the characteristic response time of solids holdup is on the order of tens of seconds. Responses to the superficial gas velocity increase are consistently faster than to decrease, while smaller particle size prolongs the response time. Stepwise increases (10% -> 20% -> 30%) in solids inventory raise the particle solids holdup in the dense phase and shorten the response time. The CPFD model demonstrates strong agreement with experimental data in both solids holdup distribution and dynamic response, with an average simulation error below 5%. The validated workflow establishes a foundation for predicting CFB transients under peak-shaving strategies.

Amid the urgent need for energy structure transformation, the co-combustion of natural gas and ammonia has attracted considerable attention as it can significantly reduce carbon emissions while avoiding the difficulty of igniting ammonia during combustion. It is crucial to effectively reduce nitrogen oxide (NO) emissions for the co-firing system to achieve efficient and clean combustion. In this study, a combustion experiment bench was set up to systematically investigate the effects of different factors, such as gas injection mode, swirl intensity, and ammonia heat ratio, on NO emissions in the co-combustion of natural gas and ammonia. The results show that the lowest NO emissions occur when natural gas is directly injected into the outer channel while ammonia is swirled into the inner channel, with a reduction of over 50% compared to other high-emission conditions. Meanwhile, same kind of gas partial swirl and partial axial injected into the combustion chamber lead to higher NO emission than that in a unified method. Additionally, NO emissions increase initially and then decrease with the increase of the ammonia heat ratio, with the peak value varying from 0.1 to 0.3 depending on the relative positions of natural gas and ammonia. These conclusions can provide guidance for industrial applications and promote the industrial application of zero-carbon ammonia fuel.

Physics-informed machine learning (PIML) represents an emerging paradigm that integrates various forms of physical knowledge into machine learning (ML) components, thereby enhancing the physical consistency of ML models compared to purely data-driven paradigms. The field of combustion, characterized by a rich foundation of physical laws and abundant data, is undergoing a transformation due to PIML. This paper aims to provide a comprehensive overview of PIML for combustion, systematically outlining fundamental principles, significant contributions, key advancements, and available resources. The application of PIML in combustion is categorized into three domains: combustion chemical kinetics, combustion reacting flows, and other combustion-related scenarios. Additionally, current challenges, potential solutions, and practical guidelines for researchers and engineers will be discussed. A primary focus of this review is to demonstrate how combustion laws can be integrated into ML, either through soft or hard constraints, via loss functions or representation models, and within coordinate-to-variable or field-to-field paradigms. This paper shows that PIML offers a unified framework linking physics, model, and data in combustion–integrating physical knowledge in model-to-data simulation and reconstruction tasks, as well as data-to-model modeling tasks–resulting in enhanced data, improved physical models, and more reliable ML models. PIML for combustion presents significant opportunities for both the combustion and ML communities, encouraging greater collaboration and cross-disciplinary engagement.

Electro-thermal energy storage (ETES) technology has presented its great potential to efficiently consume renewable energy and increase the flexibility of power grid. This paper presents an innovative ETES system that integrates electromagnetic induction heat storage (EIHS) with moving bed heat release (MBHR). A numerical simulation method based on CFD-DEM was developed to access the system's performance and evaluate its technical feasibility. In a studied case, the EI heater unit achieves uniform radial temperature distribution, adjustable temperature rise rate, and high particle heat storage density, while the tubular MBHE unit shows high heat transfer intensity (678.2-784.6 W/m2/K). The system's power-to-power conversion efficiency is approximately 30.78 %, excluding minor power consumption. The developed system offers three operation modes and two business models for peak electricity supply. The preliminary economic evaluation indicates that model 1, using valley power, has a 5-year payback period and a 21.56 % internal rate of return (IRR), while model 2, using abandoned photovoltaic/wind power, shows a 10-year payback period and an 11.26 % IRR. Further sensitivity analysis suggests model 1 is more cost-effective while model 2 offers slightly better risk resistance. This work has offered some valuable insights into the advanced enhancement and development of the ETES system, as well as its future engineering applications.

Ammonia-coal co-combustion is a promising approach for coal decarbonization. However, the introduction of NH3 tends to increase NO emissions. Therefore, understanding the formation characteristics and the associated reaction mechanisms of NO in ammonia-coal co-combustion mode is essential for its industrialized development. In this study, a high-temperature tubular furnace and CHEMKIN simulation are employed to investigate NO formation and its underlying mechanisms over a wide range of ammonia blending ratios, O-2 concentrations, and temperatures. Experimental results show that during the co-combustion of ammonia with either volatiles or char, NO peak values increase with rising O-2 concentration at low ammonia blending ratios (R = 10). However, at higher blending ratios (R >= 20), a reduction in NO peaks is observed in the high-temperature region. CHEMKIN simulations further reveal that at low temperature (1100 degrees C), increasing O-2 concentration suppresses the reaction of NH2 with NO at a low blending ratio (R = 10). In contrast, at a high blending ratio (R = 40), the conversion of HNO to NO is enhanced, and the reduction of NO by HO2 radicals is also promoted. At high temperature (1400 degrees C), increasing O-2 concentration at R = 10 mainly intensifies the competition between NO2 reduction to NO and NO oxidation to NO2. Under high blending conditions (R = 40), the conversion of HNO to NO is weakened, while multiple competing pathways between NO and NO2 emerge.

Circulating fluidized bed (CFB) coal combustion technology has advantages of excellent fuel flexibility, wide turn-down ratio, as well as the effective-cost control on SO2 and NOx emissions. As the emission standard becomes more and more stringent, new technologies to further reduce the original pollutant are desired. In this work, an in-furnace denitrification technology for CFB coal combustion using iron-based additives was proposed and experimentally assessed in an apparatus with a riser taller than 20 m. The tall CFB rig ensured coal particles to experience a chemical process like those burnt in a practical CFB boiler, with a compatible burnt-out rate and O2 content at the exit. Iron particles with an average size close to that of quartz sand bed materials were used as the initial additives. Results showed that when 10 % of iron powders with respect to the mass of the initial bed inventory was added, the iron-based additives were mainly in the middle and lower parts of the riser. The emission of NO could be reduced by 9.4 % - 27 %, and the total amount of N-containing pollutants (NO + N2O) could be reduced by 8.1 % - 9.2 %. At the same time, CO concentration in the exhaust gas decreased by 4.9 % 38.1 %. The variation degrees depended on the combustion temperature and the air staging. However, the presence of iron additives was in favor of decreasing N2O emission, it did not always decrease NO emission. In some cases, it could even increase NO emission, when combustion occurred in an oxidizing atmosphere. The results showed that the proposed in-furnace denitrification technology with iron additives for CFB coal combustion was feasible for the total nitrogen oxide removal, but conditional in NO reduction. To achieve the simultaneous NOx and N2O reduction, proper control of additive size, bed temperature and reaction atmosphere should be performed.