With the rapid growth of renewable energy under the goals of carbon peaking and carbon neutrality, power systems face increasing demand for long-duration energy storage and flexible peak regulation. Electrically heated solid particle thermal energy storage (TES) is a promising option because it offers high operating temperature, wide storage temperature range, low-cost storage media, good thermal stability, clean electric-to-thermal conversion, and strong potential for integration with renewable energy systems and coal-fired power plants. This paper aims to clarify the research progress, major bottlenecks, and future directions of this technology.

This paper reviews electrically heated solid particle TES from the perspectives of heating principles, representative devices, application scenarios, and key scientific and engineering issues. Two major routes, resistance heating and induction heating, are discussed in detail. For resistance heating, both indirect and direct modes are considered. Indirect resistance heating transfers heat from electric heating elements to particles through conduction, convection, and radiation. It has advantages such as simple structure, mature equipment, and good controllability, but it also suffers from additional thermal resistance and heat loss. Direct resistance heating allows conductive particles or conductive particle networks to generate Joule heat directly, which improves heating compactness and electric-to-thermal efficiency, while also introducing challenges related to conductivity stability, local overheating, oxidation resistance, and the formation of reliable conductive paths. Induction heating provides non-contact heating and rapid thermal response, and is attractive for high-temperature applications. However, its performance depends strongly on frequency, magnetic field intensity, coil design, particle size, electrical conductivity, magnetic permeability, and temperature-dependent material properties. In addition, induction heating systems often face higher equipment cost, cooling demand, and lower overall efficiency in practical applications. Representative devices for solid particle heating, including tubular heaters, plate heaters, fluidized-bed heaters, and moving-bed heaters, are also summarized. Tubular and plate heaters are relatively mature and suitable for small- and medium-scale systems, whereas fluidized-bed and moving-bed configurations show better heat transfer performance and greater potential for high-power and continuous operation. At the same time, they involve more complex issues such as particle flow stability, pressure drop, abrasion, temperature uniformity, and model accuracy. This paper further discusses key challenges, including high-temperature particle flow and heat transfer mechanisms, optimization of electric heating efficiency, durability of particle materials under thermal cycling, cost control, and coordinated operation with coal-fired power plants.

Electrically heated solid particle TES is a promising technical route for renewable energy integration, long-duration energy storage, and flexible operation of coal-fired power plants. Resistance heating is currently more mature and economically competitive, while induction heating has advantages in non-contact heating, rapid response, and high-temperature adaptability, but still requires progress in efficiency improvement, cost reduction, and particle material matching. Future research should focus on multi-field coupled particle flow and heat transfer, low-cost and high-performance particle materials, modular electric heating devices, heat loss control, and coordinated control strategies, so as to promote the scale-up, industrialization, and commercialization of this technology.

Biomass power generation plays a crucial role in China’s efforts to achieve the “dual carbon” goal. The goal focuses on peaking carbon dioxide emissions and reaching carbon neutrality within a predefined timeline. However, high chlorine and alkali metal contents are naturally present in biomass fuels. Due to this characteristic, biomass boilers are prone to severe high-temperature corrosion during operation. The long-term reliability and safety of boiler systems are undermined by this issue. A systematic and comprehensive review of high-temperature corrosion in biomass boilers is provided in this paper. The corrosion mechanisms, influencing factors, and mitigation technologies are covered, with the aim of providing a valuable reference for both research and engineering practices.

Firstly, the typical characteristics of high-temperature corrosion in biomass-fired boilers are outlined. On this basis, the corrosion mechanisms involving key media such as chlorine, alkali metals, and sulfur are elaborated. Subsequently, the influence of multiple critical factors on corrosion behavior is analyzed in detail. The reaction rate of corrosive processes is directly regulated by temperature. The corrosive environment is changed by flue gas composition. The formation of protective or corrosive deposits is affected by ash composition. The intrinsic corrosion resistance of boiler components is determined by material properties. Finally, a series of prevention and control technologies are summarized. These technologies have been validated through laboratory experiments or long-term engineering practice. They include fuel pretreatment (to reduce corrosive constituents), coating protection (to isolate metal surfaces from corrosive media), additive inhibition (to suppress harmful chemical reactions), and external fluidized beds (to optimize combustion and corrosion conditions). The unique application features, advantages, limitations and economic efficiency of each technology are also discussed.

Future research can be deepened from three key aspects. First, advanced materials science should be integrated to elucidate the microscopic mechanisms of multi-medium coupled corrosion. Interface reactions and damage evolution processes at the atomic and molecular levels can be uncovered. Second, efforts should be intensified to develop novel high-performance protective materials. These materials should be endowed with exceptional high-temperature stability, corrosion resistance and mechanical strength. The harsh operating environments of biomass boilers must be withstood by them. Third, an integrated and collaborative control strategy should be established. This strategy is synergistically combined with fuel pretreatment, scientific additive selection, optimized operational parameters, and advanced material protection. Full-cycle, multi-dimensional corrosion control is the ultimate goal to be achieved. Through the synergistic innovation of mechanism research, advanced material development and systematic prevention-and-control technologies, it is expected to provide essential support for the safe, efficient, and low-cost operation of biomass boilers.

Against the dual backdrop of urgent global climate governance and low-carbon transformation demands of the coal-fired power industry, carbon capture and storage (CCS) is widely recognized as a critical pathway to deep emission reduction in the power system. However, the high cost of CCS technology has severely hindered its large-scale promotion. To address this cost optimization challenge, this study aims to systematically explore the cost-driven mechanisms of the full-chain CCS system, identify key influencing factors, and propose a targeted cost-reduction paradigm, providing theoretical and practical support for the scientific deployment and commercialization of CCS in coal-fired power plants.

This study adopted the ITEAM-CCUS quantitative evaluation model, covering the full-chain CCS and integrating three core modules: geological carbon storage assessment, techno-economic analysis, and source-sink matching optimization. A systematic multi-parameter sensitivity analysis was conducted based on a sample of 165 domestic coal-fired power plants. These samples were selected to represent different regional distributions, unit capacities, and operational conditions, ensuring the generalizability and reliability of the research results. The analysis focused on key technical, economic, and geological parameters, such as absorbent regeneration heat consumption, coal price, plant utilization hours, electricity price, transportation distance, and reservoir properties.

The study revealed that the average levelized cost of the full-chain CCS is 303 yuan per ton of CO₂. Among the four chains, the capture and compression stages account for over 80% of the total cost, emerging as the primary focus for cost reduction. Specifically, capture cost is most significantly influenced by absorbent regeneration heat consumption, coal price, and plant utilization hours, and reducing regeneration heat consumption through technological innovation or improving plant operational efficiency can effectively lower capture costs. Compression cost shows a strong correlation with electricity price. Pipeline transportation cost is constrained by transportation distance and economies of scale. Storage cost is extremely sensitive to geological parameters such as reservoir’s permeability coefficient, thickness, and depth-reservoirs with higher permeability, greater thickness, and moderate depth are more conducive to reducing drilling, injection, and monitoring costs.

Based on the quantitative findings, this study proposes a systematic “scale-geology-energy efficiency synergy” cost-reduction paradigm. The specific pathways include technological innovation for low-energy consumption in the capture stage, large-scale infrastructure sharing across the full-chain CCS, refined operation and management of the CCS system, and policy incentives. This research clarifies CCS cost structures and driving factors, providing a feasible framework for governments, enterprises, and research institutions. It offers important theoretical and practical reference for promoting large-scale, commercial CCS application in coal-fired power plants, advancing power system decarbonization, and supporting global climate governance.

Configuring hydrogen energy storage and waste heat recovery in data centers directly powered by green electricity constitutes an effective approach to mitigate renewable energy intermittency and improve overall energy efficiency. This study aims to verify the technical and economic feasibility of this strategy in enhancing the operational performance of data center energy systems and reducing operating costs.

Accordingly, a heat pump-assisted organic Rankine cycle is proposed to recover data center waste heat for power generation. At the same time, hydrogen energy storage is used to maintain power supply-demand balance amid fluctuations in renewable energy. Subsequently, an integrated energy-exergy-economic model is developed, and system performance is evaluated at monthly and annual time scales using 2023 meteorological data from Guiyang, China. Furthermore, a sensitivity analysis is conducted to investigate the impacts of varying server utilization rates and six low global warming potential (GWP) working fluids on overall system performance.

The results demonstrate that the system achieves energy and exergy efficiencies of 57.12% and 55.36%, respectively, with a data center energy usage effectiveness of 1.3 and an energy reuse effectiveness of 0.74. Economic analysis indicates a dynamic payback period of 6 years and a net present value of 1.749 6 million yuan. Notably, at a server utilization rate of 90%, the low-GWP R161/Pentane working fluid pair outperforms the high-GWP R134a/R245fa combination.

The synergistic integration of waste heat recovery and hydrogen energy storage effectively improves techno-economic performance, providing a viable technical pathway for data center operators to invest in and deploy supporting energy systems for direct green electricity supply.

Compressed air energy storage technology is mature and flexible to operate, making it a highly promising energy storage solution. To effectively improve the performance of compressed air energy storage systems, this study proposes an integrated system that couples them with concentrated solar power (CSP) plants.

During the energy storage phase, low-temperature condensate from the solar thermal power plant’s regenerative system is used to cool the high-temperature compressed air at the compressor outlet, thereby recovering and reusing the compression heat. During the energy release phase, the compressed air is heated in stages using high-temperature molten salt and high-temperature feedwater from the CSP plant. Through system integration, the compression heat is effectively utilized, while simultaneously reducing the thermal storage equipment required in the original compressed air energy storage system. A thermodynamic model of the coupled system was constructed, and energy, exergy, and economic analyses were conducted on the proposed coupled system to evaluate its performance.

The proposed system achieved a round trip efficiency of 74.95% and an exergy efficiency of 79.78%, with an energy storage density of 8.18 MJ/m³. Furthermore, the system’s dynamic payback period was 4.42 years，and its net present value was 49.358 9 million yuan.

The proposed integrated system of solar thermal power station and compressed air energy storage exhibits significant efficiency improvement and good economic performance, providing valuable reference for the development of renewable energy coupled energy storage systems.

To achieve recovery and utilization of low-grade waste heat, we proposed a phase change thermal storage unit incorporating “tree-branch fins + foam metal”, and co-optimized its structural and material parameters using response surface methodology and orthogonal experiments.

Under typical operating conditions (80 ℃, 0.005 m/s), tree-branch fins reduced the melting time of the phase change material (PCM) by 10.7% compared to straight fins, with optimal parameters including a length ratio of 1.143, a width ratio of 1.057, and a branching angle of 68.987°. Regarding system structure, the counterflow arrangement of dual heat exchanger tubes decreased the melting time to 558 s, and further filling with foam metal shortened it to 181 s. Although increasing porosity enhances the proportion of PCM, it weakens the structural support of the metal framework, thereby prolonging the melting time.

In conclusion, the integration of tree-branch fins and foam metal significantly improves the thermal storage performance of phase change thermal storage devices. Subsequently, staged thermal energy storage can improve the efficiency of heat storage. The optimal configuration for a three-stage cascade is put forward: Stage I: 0.9 porosity nickel foam + n-octadecane; Stage II: 0.5 porosity nickel foam + n-octadecane; Stage III: 0.5 porosity nickel foam + stearic acid PCM.

It can provide an integrated design basis for the efficient capture and reuse of low-grade waste heat at 50~60 ℃.

This article aims to improve the corrosion resistance of 304 stainless steel in high-temperature chloride molten salts, clarify the application effect and corrosion inhibition mechanism of aluminum powder as a corrosion inhibitor, and provide a practical reference for the material protection of solar thermal storage molten salt systems.

The high-temperature electrochemical corrosion behavior of 304 stainless steel was investigated in a ternary chloride molten salt (NaCl-KCl-MgCl₂) at 700 ℃ with the addition of aluminum powder at mass fractions of 0, 1%, 2%, and 5% respectively. Potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) were employed to evaluate the corrosion kinetics and interfacial characteristics. The surface and cross-sectional morphologies, elemental distribution, and phase composition of corrosion products were analyzed using scanning electron microscopy combined with energy-dispersive spectroscopy (SEM/EDS) and X-ray diffraction (XRD).

The addition of aluminum powder significantly suppressed the corrosion of 304 stainless steel. With 5% aluminum powder addition, the corrosion current density decreased from 299.98 mA/cm² (without addition) to 31.673 mA/cm², representing a reduction of 89.4%. The polarization resistance increased markedly from 0.348 Ω (without aluminum) to 2.974 Ω (with 5% aluminum), indicating enhanced resistance to corrosion reactions. Electrochemical impedance spectroscopy (EIS) analysis revealed that the addition of aluminum altered the corrosion control mechanism from diffusion-controlled (without aluminum) to a dual-layer synergistic protection system at higher aluminum contents. After 100 h of corrosion，the thickness of the internal diffusion layer was significantly reduced from 150 μm (without aluminum) to 36 μm (with 5% aluminum powder addition). XRD and SEM/EDS analysis showed that at aluminum additions of 2% and 5%，a continuous and dense Al₂O₃ layer formed on the surface，while aluminum diffused inward to form an aluminum-rich layer and intermetallic AlNi₃ phase within the alloy subsurface. This dual-layer structure effectively suppressed the outward diffusion of Cr and Fe，thereby mitigating corrosion.

The corrosion inhibition mechanism of aluminum powder involves a synergistic protective process. Aluminum preferentially reacts with oxidizing impurities (e.g., moisture and oxygen) in the molten salt, forming a stable Al₂O₃ film on the alloy surface. Simultaneously, a portion of aluminum diffuses inward, creating an aluminum-rich layer and precipitating AlNi₃ phases, which together act as an internal diffusion barrier. This combined surface film and internal diffusion barrier system effectively blocks the outward migration of Cr and Fe, substantially reducing the corrosion rate. The results demonstrate that adding aluminum powder to chloride molten salts is a simple and effective strategy to enhance the corrosion resistance of 304 stainless steel. Future work should focus on the evaluation of the long-term durability and erosion resistance of this protective system under dynamic flow conditions, to facilitate its practical applications in concentrating solar power systems.

To address the issues of insufficient renewable energy integration into the power grid and the high exhaust steam loss in coal-fired power units, a novel Carnot Battery system integrated with a steam ejector is proposed to provide a technical solution for the flexibility transformation of coal-fired units.

This study designed two new systems, System Ⅰ and Ⅱ, utilizing turbine exhaust steam and extraction steam as low-temperature heat sources. System Ⅱ introduces a steam ejector, which uses exhaust from the intermediate-pressure turbine to entrain the exhaust steam, thereby increasing the cold source temperature of the heat storage cycle. Based on the EBSILON Professional, thermodynamic modeling was conducted to compare the coefficient of performance (C_COP), round-trip efficiency (η_RTE), and exergy loss of each system, followed by a techno-economic assessment.

Thermodynamic analysis indicates that the exhaust steam losses of System Ⅰ and Ⅱ are reduced by 38.19 MW and 39.62 MW, respectively, compared to the reference system. Benefiting from the elevated cold source temperature, the C_COP of both systems increased to 1.36 and 1.42. Sensitivity analysis shows that System Ⅱ achieves an optimal round-trip efficiency of 61.51% at a cold source outlet temperature of 55 ℃, an improvement of 2.11 percentage points over the reference system. In terms of techno-economic performance, System Ⅱ performs best, with a dynamic payback period of 9.44 years and a levelized cost of storage as low as 2 094.59 yuan/(MW·h).

The novel System Ⅱ not only effectively reduces energy consumption and improves energy storage efficiency but also demonstrates significant economic competitiveness, which is of great importance for promoting the low-carbon transition of China’s energy industry.

Conventional combined heating and power (CHP) systems often suffer from suboptimal thermal integration and limited exergy utilization, resulting in low overall energy efficiency and significant carbon emissions. To address these challenges, this study proposes a novel high-efficiency CHP system based on the synergistic integration of a solid oxide fuel cell (SOFC) and a lithium bromide (LiBr) absorption heat pump. The architecture is specifically designed to maximize cascaded energy recovery and enhance comprehensive thermodynamic and economic performance.

A comprehensive steady-state model encompassing thermodynamic and economic analysis was developed to evaluate the system behavior. In the proposed configuration, unreacted fuel in the SOFC anode exhaust is combusted using oxy-fuel technology, yielding a CO₂-concentrated flue gas suitable for carbon capture while simultaneously upgrading waste heat quality. The high-temperature flue gas is then recovered through an advanced cascaded heat exchanger network, sequentially enabling cathode air preheating, endothermic methane reforming, and high-pressure steam generation. This steam serves as the thermal driving source for the LiBr absorption heat pump to meet heating demands. A detailed parametric sensitivity analysis was conducted to investigate the effects of the steam-to-carbon ratio, SOFC operating temperature, and fuel utilization factor on key performance indicators.

Simulation results show that increasing the steam-to-carbon ratio monotonically reduces both SOFC electrical efficiency and overall thermal energy utilization efficiency, whereas the coefficient of performance (COP) of the absorption heat pump remains stable at approximately 1.72. Higher SOFC operating temperatures significantly improve electrochemical kinetics and flue gas quality, thereby enhancing both electrical and thermal performance. A clear trade-off is observed with fuel utilization: higher fuel utilization factor increases electrical output but diminishes the availability of high-grade heat for downstream recovery. Under optimized conditions (with the steam-to-carbon ratio of 2, temperature of 1 000 ℃, and fuel utilization ratio of 0.85), the system achieves an electrical efficiency of 52%, an exergy efficiency of 56.6%, and an overall thermal energy utilization efficiency of 100.54% (defined on the basis of the fuel’s lower heating value, including all recovered thermal energy). Compared to a conventional natural gas-fired CHP benchmark, the proposed system improves the thermal utilization efficiency by 20%, and increases the exergy efficiency by 2.6%. Economic evaluation yields a levelized cost of exergy of 0.102 6 dollars/(kW·h) and a dynamic payback period of 8 years under current industrial energy pricing.

This coupled system significantly improves the energy utilization efficiency and comprehensive performance through the optimization of the energy cascade utilization mode. It demonstrates substantial economic feasibility and potential for engineering applications. The identified influence mechanisms of key parameters provide a theoretical foundation for the optimal design and operational control of such systems.

The carbon capture pretreatment system faces challenges such as high energy consumption, unstable purification efficiency, and significant fluctuations in SO₂ absorption efficiency due to variations in pH value of washing solution. This study proposes a hybrid modeling method combining mechanism models with data-driven by taking the carbon capture pretreatment system in a power plant as the research object.

By integrating chemical reaction kinetics and decision tree algorithms, the model is implemented in Python to predict key parameters accurately, including the pH value of the washing solution and the SO₂ mass concentration at the system outlet.

The model yields a correlation coefficient of 0.85 and 0.80 for the pH value of the washing solution and the SO₂ mass concentration at the system outlet, respectively. The values fall within an acceptable error band, indicating the proposed model has good simulation performance. Moreover, a sensitivity analysis driven by baseline plant data further reveals that the model faithfully reproduces the system response to perturbations in inlet flue-gas temperature, liquid-to-gas ratio, and alkali feed rate.

These outcomes furnish a quantitative foundation for subsequent optimization of the CO₂-capture pretreatment system, offering clear avenues for energy minimization and robust steady-state operation.

In the context of achieving the “dual-carbon” goals in the new era, coal-fired cogeneration systems are required to be highly efficient, flexible, and low in pollution and carbon emissions.

To tackle these challenges, this study proposes a novel system that integrates a supercritical CO₂ cycle with split-flow heating and low-temperature regeneration (SR-SCO₂-CHP), an ultra-low emission (ULE) flue gas control module, and a vacuum temperature swing adsorption (VTSA) carbon capture module (denoted as the SR-SCO₂-CHP-ULE-VTSA system). A system using monoethanolamine (MEA) for carbon capture (SR-SCO₂-CHP-ULE-MEA) serves as the benchmark for comparison. A comparative exergy analysis is conducted.

The results demonstrate that the proposed system achieves superior exergy efficiency across all electrical loads, because the exergy loss of the VTSA carbon capture submodule is less than one-third of that of the MEA. The exergy losses of MEA mainly occur in the absorption tower and desorption tower, which account for 80% of the total exergy losses of the carbon capture submodule. However, the exergy losses of VTSA adsorption & desorption tower and the pressure machine are relatively large, accounting for more than 60% of the total exergy losses of the carbon capture submodule. At full load, its exergy efficiency reaches 39.84%, significantly outperforming the benchmark system’s 35.16%. Furthermore, the proposed system enables effective thermo-electric decoupling through adjustments in the heat split ratio (x₁) and the split ratio of CO₂ turbine driving vacuum pump (x₂). The exergy efficiency of the system decreases as the split ratio x₁ and x₂ increase under any electrical load, and the optimal split ratios of x₁ and x₂ increase as the electrical load decreases. At 100% electrical load, the optimal values for x₁ and x₂ are 0.52 and 0.14, respectively. The carbon reduction capability of the proposed system is also remarkable. Across the electrical load range from 100% to 30%, the carbon reduction increases from 11.9 g/(kW·h) to as high as 85.3 g/(kW·h), demonstrating a significant advantage over the benchmark system.

This work confirms the SR-SCO₂-CHP-ULE-VTSA system as a promising solution for highly efficient and low-carbon coal-fired cogeneration. It should be noted that in terms of economic performance, the initial investment of the carbon capture module of the SR-SCO₂-CHP-ULE-VTSA system is closely related to the performance of the adsorbent material, and further optimization of the adsorbent is required to reduce equipment size and cost. Additionally, in terms of operation, its carbon capture module has a complex structure and high requirements for multi-tower operation switching, so its technical maturity needs to be further improved to promote its industrial application.

This study aims to enrich the experimental study of the ORC using mixture working fluids and analyze its transient and steady-state operating characteristics.

A 4-kW organic Rankine cycle (ORC) prototype using R236fa/R123 was tested to obtain the transient and steady-state operating data.

The results of the ORC system at different mixture concentrations reveal that the operation characteristics of the ORC with mixed working fluids are consistent with those using a pure working fluid. The adjustment of the working fluid mass flow rate significantly affects the system output power, while it has a limited impact on the thermal efficiency. The ORC system operates relatively stable with the variation in the mixture concentration, as it has a minimal effect on both the output power and thermal efficiency. With the increase in the R236fa mass fraction, the expander inlet pressure is stable while its outlet pressure gradually increases, resulting in high pressure ratios. This phenomenon indicates that adopting the expander with a larger internal volume ratio can optimize the ORC performance. The trade-off between the exergy destructions of the evaporator and condenser at different mixture concentrations is the main factor determining the system performance. The temperature glide caused by the condenser pressure drop limits the attribution of the mixture working fluid to optimize the system performance.

In the design and operation of mixed-working-fluid ORC systems, it is crucial to consider the matching of the condenser pressure drop and the working fluid inherent properties.

In practical energy and chemical engineering systems, pipeline layouts often exhibit complex multi-directional configurations due to equipment arrangement, spatial constraints, and process requirements, rather than simple straight horizontal or vertical sections. This is particularly evident in applications such as compact heat exchangers for supercritical carbon dioxide (S-CO₂) Brayton cycles, nuclear reactor cooling circuits, and chemical transport pipelines, where the working fluid frequently undergoes abrupt changes in flow direction. Among these configurations, the L-shaped bend, a classic directional-changing structure that connects horizontal and vertical pipe sections, is especially common and plays a crucial role in achieving spatial redirection of the working fluid. Therefore, investigating the heat transfer characteristics of S-CO₂ in L-shaped bends is of significant importance. This study aims to investigate the effect of buoyancy-induced density stratification in a heated horizontal section on the subsequent heat transfer in a vertical upward flow under different experimental parameters.

An experimental system with high expandability was established, featuring a single-cycle S-CO₂ heat transfer test platform utilizing stainless steel circular pipes with adjustable lengths and bend angles. Experiments were conducted to study the flow and heat transfer characteristics of S-CO₂ inside a horizontal-to-vertical L-shaped turning pipe.

The experimental results reveal two distinct types of “asymmetric heat transfer deterioration” in the turning pipe: one characterized by asymmetry in the severity of deterioration, and the other by asymmetry in its location. When the wall heat flux is increased, wall temperature peaks indicating heat transfer deterioration appear in the vertical section, with unequal peak values on the two sides, representing asymmetry in severity. A further increase in wall heat flux shifts the deterioration position toward the inlet, while the enthalpy at which deterioration initiates remains unchanged, indicating that the wall heat flux does not affect the onset enthalpy of deterioration. When the heat flux is raised sufficiently for the deterioration to advance to the inlet of the vertical section, the wall temperature peak on the inner side occurs earlier than that on the outer side, demonstrating asymmetry in the location of deterioration.

The study demonstrates that asymmetry in severity originates from non-uniform cross-sectional mass flow distribution caused by temperature stratification extending from the horizontal section. In contrast, asymmetry in location occurs under high-temperature and high-heat-flux conditions due to the earlier fulfillment of deterioration criteria within the inner-side boundary layer. This research elucidates the coupling effect between buoyancy and flow redirection in L-shaped pipes, providing an experimental basis for the design of related heat exchange equipment.

To investigate the effects of biomass gas co-firing on combustion stability and in-furnace parameters under low-load conditions, a 660 MW tangentially fired boiler was taken as the research object to carry out the study. A stability index was proposed, and a combined approach of numerical simulation and artificial neural network (ANN) was employed.

Comparative analysis was conducted between pure coal and co-firing conditions at loads of 100%, 70%, 50%, and 30%.

The results show that the deviation of the temperature stability coefficient (M_T) under co-firing is less than 3.9%, indicating stable combustion at low load conditions. When the unit load decreases from 100% to 70%, the average temperature in the main combustion zone drops by 147.87 K for pure coal and 69.37 K for co-firing, indicating a slower temperature decay. At 30% load, the NO_x volume fractions in the reduction and burnout zones under co-firing are 0.051 2% and 0.044 4%, which are lower than 0.093 3% and 0.078 6% under pure coal combustion condition, with smaller fluctuations of other parameters. Furthermore, an artificial neural network (ANN) model was developed to describe the complicated relationships among in-furnace parameters, and the results show that the regression coefficients R² for temperature, CO₂ volume fraction, and NO_x volume fraction predictions are all greater than 0.96 in both pure coal and co-firing conditions.

This study provides support for optimization and prediction of low-load operation in biomass gasification co-firing boilers.

To address the issues of low reheated steam temperature and local overheating of platen superheaters (PSH) during low-load operation of a 660 MW ultra-supercritical tangentially fired once-reheat boiler, this study proposed a wall-mounted flue gas recirculation (FGR) arrangement in the burner region. The aim was to synergistically raise reheated steam temperature and suppress PSH overheating while maintaining combustion stability.

Numerical simulation was performed at 40% rated load to optimize the proposed layout. First, the baseline case and corner-mounted and wall-mounted concentrated FGR arrangements were compared. Subsequently, the feasibility of wall-mounted grouped injection was investigated.

The results indicated that: corner-mounted FGR significantly increased the ignition distance of pulverized coal jets, which adversely affected low-load combustion stability. Both fire-side and rear-side concentrated FGR increased the heat absorption of the high-temperature reheater, but neither could simultaneously mitigate PSH local overheating. Fire-side grouped FGR substantially enhanced heat absorption of the reheater but still carried a risk of PSH overheating, whereas rear-side grouped FGR reduced the overheating risk but yielded only limited reheater improvement. A combined grouped arrangement, in which flue gas was injected through the two lower layers on the fire-side wall together with the upper layer on the rear-side wall, increased the heat absorption of the reheater by 18.9%, effectively mitigated local overheating of the PSH, and maintained stable combustion.

These findings provide design and optimization references for safe, flexible, and efficient boiler operation across wide load ranges in next-generation coal-fired power plants.

The low-temperature (–20~ –40 ℃) oxidation adsorption of multiple pollutants from coal-fired flue gas onto activated carbons enables their integrated removal, which has promising application prospect and environmental benefits.

This article studied the adsorption processes of NO and SO₂ by four activated carbons (graded-pore activated carbon, coal-based activated carbon, and two coconut shell-based activated carbons) in inert atmosphere and simulated flue gas under low temperature conditions of –20 ℃.

The experimental results showed that in an inert atmosphere, the adsorption performance of the four activated carbons for NO was weak, with a saturated nitrogen capacity of less than 0.07 mg/g, and the saturated sulfur capacity for adsorbing SO₂ was 31.70~57.07 mg/g. In simulated flue gas conditions, the presence of O₂ increased the saturated nitrogen capacity of activated carbons by three orders of magnitude and the saturated sulfur capacity by 2~5 times. The optimal coconut shell activated carbon-2 had a saturated nitrogen capacity of 175.70 mg/g and a saturated sulfur capacity of 320.65 mg/g. Density functional theory (DFT) calculations show that the adsorption binding energies of NO, SO₂, and their oxides on the zigzag edge carbon model follow the order of NO₂> SO₃> SO₂> NO. After NO and SO₂ are oxidized by O₂ into NO₂ and SO₃, their adsorption on activated carbon surfaces is significantly enhanced.

The research results can provide an important theoretical basis for the integrated adsorption and removal of NO and SO₂ in coal-fired flue gas under low temperature conditions.

With the popularization of co-combustion of high-alkali coal in Xinjiang, systematic studies on the difference and mechanism of alkali metal poisoning resistance between honeycomb and plate SCR catalysts remain insufficient. Most existing researches are based on the simulation of single alkali metal salts in the laboratory, whereas actual fly ash constitutes a complex mixture. The significant discrepancy between simulated conditions and real flue gas from high-alkali coal combustion results in limited engineering guidance value of relevant research findings.

In this work, actual fly ash from power plants was adopted, and typical flue gas conditions were simulated in a laboratory fixed-bed reactor. The physical and chemical property changes of fresh and aged honeycomb and plate SCR catalysts were compared. Combined with specific surface area measurement, NH₃-TPD analysis of surface acidity, XPS characterization of vanadium valence states and other techniques, the deactivation behaviors of the two catalysts upon alkali metal poisoning were systematically investigated.

Although plate catalysts are more susceptible to sintering deactivation under extreme high-alkali conditions, and bulk diffusion deactivation is difficult to recover via physical or mild chemical regeneration, their denitrification efficiency decays more slowly than that of honeycomb catalysts. At the same alkali loading, the denitrification activity of honeycomb catalysts decreased by 29.5% within 4 800 hours, while that of plate catalysts only dropped by 24.6%. The vanadium valence cycle of honeycomb catalysts is more easily interrupted by alkali metals, which suppresses the “fast SCR pathway” relying on NO→NO₂ conversion. Moreover, their Brønsted acid sites are more prone to neutralization by alkali metals.

Therefore, plate catalysts are the preferred choice for long-term denitrification in industrial scenarios involving co-combustion of high-alkali coal.