Latest Articles[Objective] Particle deposition within the tubes of supercritical boiler heat exchangers is one of the key factors affecting the unit’s ability to operate across a wide range of loads. Clarifying the initial nucleation and deposition behavior of particles within the tubes is crucial for improving the stability of the unit’s wide load range operation. This paper aims to conduct relevant experimental and simulation studies by using a supercritical water tube deposition test system.
[Methods] The experiments monitored changes in the outer wall temperature in realtime during the process and examined samples from the experimental section after offline removal to observe the deposition behavior of particles and the microscopic morphology. By sectioning the experimental samples, the microstructure of the particle deposition layer on the inner tube wall was examined, and particle samples collected via high-pressure filters were analyzed to determine particle composition, particle size, and other characteristics. The simulations focused on the influence of particle oxidation and nucleation on the distribution of deposits. First, experimental data were used to select an appropriate turbulence model. A particle nucleation model based on classical nucleation theory was established and combined with the Euler-Lagrange method. A random walk model was incorporated to improve the accuracy of wall surface predictions. The axial deposition distribution of particles was simulated, and the effects of particle nucleation and roughness factors on the patterns o f particle deposition were analyzed.
[Results] The results indicate that the particles are primarily micron -sized spherical Fe₃O₄ clusters with a median cluster diameter of 5.832 μm, and the thickness of the deposition layer tends toward a dynamic equilibrium over time; A comparison of the simulation results with experimental data from multiple centers revealed that the constructed ionic oxidation nucleation model demonstrates good applicability; the influence of particle nucleation on deposition distribution is related to multiple factors, specifically: in the subcritical region, where fluid density and viscosity are high, fluid flow is the primary factor affecting particle deposition, while in the supercritical 2 region, the larger the particle size and the higher the nucleation temperature, the smaller the influence of the fluid on the particles; the impact of increasing wall roughness on particle deposition exhibits self-limiting behavior; when the average wall roughness exceeds five times the particle diameter, changes in roughness have no significant impact on the particle deposition distribution; within the supercritical region, the influence of roughness on particle deposition is relatively small.
[Conclusion] This study is of great significance for elucidating the initial nucleation and deposition behavior of particles within supercritical heat exchanger tubes and for improving the wide -load peaking stability of power generation units.
Amine aerosol emission during the CO 2 capture process is a critical issue leading to solvent loss and environmental risks. This work aims to elucidate its formation mech anism and the influence of key operational parameters. The emission characteristics (mass concentration and size distribution) of amine aerosols were systematically investigated on a 20 m3/h pilot-scale chemical absorption platform using monoethanolamine (MEA) as the solvent. The effects of five key parameters were examined: condensation nuclei concentration (from none to 1.03×106 cm-3), inlet CO2 concentration (0 % to 15 % by volume), flue gas temperature (40 to 70 ℃), lean liquid temperature (35 to 55 ℃), and lean CO 2 loading (0.02 to 0.48 mol CO 2/mol MEA). An Electrical Low -Pressure Impactor (ELPI +) was used for real -time aerosol measurement. The results demonstrate that the presence of condensation nuclei is a prerequisite for significant aerosol formation, with heterogeneous condensation on nuclei surfaces being the dominant mechanism, capable of increasing the aerosol mass concentration by an order of magnitude. The aerosol emission peaked at an inlet CO 2 concentration of approximately 10 %. Increases in both flue gas temperature and lean liquid temperature were found to exacerbate aerosol emissions due to enhanced amine volatility and reaction kinetics. Lean CO 2 loading was identified as the most influential parameter. Increasing the loading from 0.02 to 0.48 mol CO2/mol MEA resulted in a drastic reduction of aerosol mass concentration by 94.6 %, 2 http ://rlfd.cbpt.cnki.net which is primarily attributed to the decreased concentration and volatility of free MEA in the liquid phase. This study elucidates the growth mechanism of amine aerosols dominated by heterogeneous reactions and interfacial chemistry. It clearly indicates that effective emission control can be achieved through a dual strategy: removing condensation nuclei from the inlet flue gas at the source and optimizing operational parameters, notably operating at a moderately high lean CO 2 loading. The findings provide crucial experimental data and theoretical support for predicting, mitigating, and optimizing amine aerosol emissions in industrial amine-based carbon capture systems.
Proposes a data -driven “LSTM-Transformer-SHAP” hybrid model framework for dynamic operational anomaly detection, diagnosis, and performance optimization of combined gas -steam cycle unit heat recovery steam generators. First, a Long Short -Term Memory (LSTM) network model is used to accurately predict turbine power and steam heat separately; then, a transformer adaptive reconstruction algorithm is applied to identify anomalies in the steam cycle operational state, and STL decomposition residuals clarify the type of anomaly; next, SHAP values are used to locate high-contribution parameters; finally, case analysis is conducted to estimate macro uncertainty and formulate feedforward optimization strategies. The results show that the LSTM model predicts flue gas h eat and steam heat with mean absolute percentage errors (MAPE) of 2.0% and 1.2% respectively; the LSTM model predicts turbine power and steam temperature with MAPEs of 1.5% and 0.3% respectively; SHAP attribution analysis yields a MAPE of 0.21% for heat re covery steam generator steam temperature. After optimizing the performance trend anomalies of the heat recovery steam generator , the reheat steam temperature and high -pressure main steam temperature can be increased by an average of 2.30° C and 4.68° C respe ctively under steady -state conditions, and steam cycle output can be increased by an average of 2.96 MW under steady-state conditions.
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 reduce the production costs and carbon emissions associated with phase change composite materials, coal gangue was utilized as the skeletal raw material, and NaNO3 was used as the phase change material to prepare of composite thermal energy storage materials. Through the cold pressing and hot sintering method, nine distinct composite phase change materials with varying coal gangue to NaNO3 ratios were successfully synthesized. The fundamental properties of these coal gangue-based composite phase change materials were systematically investigated, encompassing thermal storage capacity, microstructural characteristics, mechanical strength, chemical compatibility, and economic viability. Results demonstrated that the composite with a coal gangue to NaNO3 mass ratio of 4.5:5.5 (designated as sample SC3) exhibited optimal performance across all evaluated parameters. Specifically, sample SC3 achieved a mechanical strength of 49.33 MPa. Within the temperature range of 100 ℃ to 335 ℃, its thermal storage capacity reached 399.29 J/g, accompanied by a thermal conductivity of 1.484 W/(m·K). Elemental distribution within this composite was found to be homogeneous, and chemical compatibility between constituents was excellent. Furthermore, after undergoing 1858 thermal cycles of heating and cooling, sample SC3 retained remarkable thermal storage performance, stable mechanical properties, and maintained its physical integrity without degradation.
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 ℃.
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