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Mooring failure feature recognition of offshore floating wind turbine
LI Shujun;LIU Min;YI Ruiji; ZOU Xiaolin;ZHANG Qiang[Objective] Mooring safety is the key to the stable operation of offshore floating wind turbines. Identifying mooring failure characteristics in advance and reducing the difficulty and cost of mooring monitoring are conducive to the healthy development of offshore wind power. [Methods] this paper establishes a floating wind turbine model of ITI Energy Barge platform equipped with NREL 5 MW wind turbine. Taking the model mooring system as the research object, based on the convolutional neural network (CNN) model, the platform response data after mooring failure at different positions are self-learned and classified, the mooring failure characteristics are identified, and the results are visualized and analyzed. recognized under different mooring states. [Results] The results show that the CNN model can accurately identify the mooring failure characteristics from the 3 response variables of displacement, velocity and acceleration of the floating wind turbine under complex loads. When the CNN model is iterated 200 times, the accuracy of the training set and the verification set of displacement, velocity and acceleration reaches more than 98.0%. The loss of the training set of displacement,velocity and acceleration is 0.13, 0.02 and 0.05, and the loss of the verification set is 0.20, 0.05 and 0.05. After mixing 6 different Gaussian white noises, the CNN model still maintains about 99.0% recognition accuracy for the 3 response variables of the wind turbine, and the model has good robustness. The t-SNE visualization method can gradually reduce the dimension to observe the data characteristics of the three response variables, and its discrimination becomes obvious with the gradual deepening of convolution. [Conclusion] The method described in this paper is helpful to identify the mooring failure characteristics in advance and ensure the stable operation of offshore floating wind turbines.
Research progress on molten salt thermal energy storage for flexibility retrofit of tcoal-fired power units
DING Tianyang;CHEN Hui2;ZHANG Chaoqun;CAO Chuansheng;TANG Chang;JIANG Cong;ZHANG Yang;CHEN Wen;YU Jie[Objective]Molten salt heat storage for peak load shaving and frequency adjustment is an important means to achieve flexible operation of coal-fired power plant. The coupling of coal-fired power plant with molten salt storage systems determines both the depth of peak load shaving and the load ramping speed, impacting the economic efficiency of coal-fired power plant. [Methods]Summarizing the related research progress in molten salt heat storage for peak load shaving and frequency adjustment is crucial for optimizing the coupling of molten salt systems with coal-fired power plant. [Results](1) The safe operating temperature of molten salt determines the coupling scheme with thermal power units. Both solar salt and HITEC salt can achieve deep peak shaving, but solar salt cannot utilize latent heat of steam; HITEC salt can utilize latent heat of steam but incurs higher exergy losses. (2) The existence of the heat exchanger pinch point means HITEC salt cannot directly heat to the highest operational temperature and requires a mid-temperature tank for flow regulation. (3) The highest safe operating temperature of solar salt is slightly higher than the main steam temperature of subcritical units, allowing direct heating of water and low-parameter steam to main steam/ reheat steam for fast ramping speed. However, for supercritical and ultra-supercritical units, the highest safe operating temperature of solar salt is lower than the main steam and reheat steam temperatures. (4) Solar salt requires a significant amount of energy to heat feedwater to main steam/ reheat steam due to the large amount of the latent heat, leading to substantial losses. Optimizing the extraction location can reduce these losses and increase the round-trip efficiency of the molten salt system. (5) Current engineering demonstrations show that molten salt energy storage for peak shaving is feasible, achieving deep peak shaving and rapid ramp-up. However, further research is needed to increase the round-trip efficiency of the system. [Conclusion]Molten salt TES effectively enhances operational flexibility, yet salt selection must align with unit parameters (sub/supercritical). Future development should focus on multi-heat source synergy, intelligent control, and low-melting-point salts to improve economics and round-trip efficiency.
Simulation study of flow heat transfer performance of air-cooled tower enhanced by adding horizontal baffles
LONG Hao;QIAN Baiyun;WANG Ruikun;ZHU Xiaoxun;WANG Yating;LIANG Ruipeng[Objective] The temperature of synchronous condensers is critical to their stable operation, while the heat exchange efficiency of external cooling systems is susceptible to ambient crosswind. This study aims to investigate the negative effects of crosswind on the flow and heat transfer performance of a 300 Mvar air-cooled tower and propose the installation of horizontal baffles to optimize airflow distribution and enhance heat exchange. [Methods]A three-dimensional physical model and mathematical model of the air-cooled tower were established using computational fluid dynamics (CFD). The standard k-ε turbulence model and porous media simplification were applied to simulate the heat exchanger. Numerical simulations analyzed the airflow, temperature, and pressure fields under crosswind speeds (0~12m/s) and evaluated the impact of horizontal baffle lengths (0.5~3 m). Grid independence verification ensured computational accuracy with approximately 4.8 million grids. [Results] The simulation results indicate that crosswind severely degraded the performance of the first unit (windward unit). At 12 m/s, the inlet mass flow rate decreased by 48% (from 20.36 kg/s to 10.69 kg/s), and the inlet temperature rose to 311 K due to negative pressure zones and vortices causing hot air recirculation. Installing horizontal baffles significantly improved flow conditions: A 3 m baffle reduced the mass flow rate loss to 0.7% and lowered the inlet temperature to ambient levels (300 K). Longer baffles increased the total heat transfer rate, but the improvement rate diminished. A 2 m baffle was optimal, increasing the heat transfer rate by 12.89% at 8 m/s wind speed with manageable pressure drop. Other units showed minimal sensitivity to crosswind and baffles, with fluctuations below 5%. [Conclusion] Horizontal baffles effectively suppress negative pressure zones and vortices, optimizing airflow distribution and heat exchange efficiency at the windward side. The 2 m baffle achieves the best balance between performance enhancement and engineering feasibility, providing theoretical guidance for energy-efficient design and wind resistance optimization of air-cooled towers.
Study on preparation of FeCl3 modified hydrothermal carbon and its Hg0 removal mechanism
YUAN Shengtao;ZHANG Ziqi;SONG Baizhen;WU Qiaonan;CHEN Yaowen;WANG Shu;ZHOU Qiang[Objective] Mercury, a toxic heavy metal with bioaccumulative and long-range transport capabilities, is predominantly emitted from coal-fired boilers. Under carbon neutrality initiatives, developing cost-effective mercury sorbents using zero-carbon biomass resources hasbecome critical for controlling Hg~0 emissions from coal flue gas.[Methods]Herein, FeCl_(3)-modified hydrochar (Fe_(1.3)-HC) was synthesized from wood waste via hydrothermal carbonization. Its Hg~0 removal performance was systematically evaluated in a fixed-bed experimental system under varying temperatures (50-250 ℃), inlet Hg0 concentrations (15.4-44.9 μg/m³), and SO₂levels (0-2 400 mg/m³). Quantum chemical calculations were conducted to elucidate the adsorption mechanism.[Results]Fe_(1.3)-HC exhibited exceptional Hg~0 removal efficiency (>98%) across tested conditions. O_(2) enhanced Hg~0 oxidation, while SO_(2) promoted Hg fixation via HgSO_(4) formation. DFT calculations identified Fe-top sites on α-Fe_(2)O_(3) (0 0 1) as preferential sites for Hg~0 chemisorption, with strong adsorption energy (-53.21 kJ/mol), short Hg-O bond length (2.760 Å), and significant charge transfer (0.31e). PDOS analysis confirmed orbital hybridization between Hg~0 and Fe/O atoms, forming stable chemical bonds，The strong interaction mechanism of Hg~0 with Fe and O atoms is verified from the electronic scale.[Conclusion]This work optimized FeCl_(3)-modified hydrochar synthesis parameters and deciphered its Hg~0 removal mechanism, providing experimental and theoretical foundations for developing sulfur-resistant, wide-temperature-adaptable sorbents for industrial mercury control.
Application and prospect of large language model in wind power generation
JING Dichun;ZHANG Tianlin[Objective] As the global reliance on renewable energy increases, wind power generation, as an important part of it, is receiving more and more attention. The rapid development of artificial intelligence technology, especially the rise of large language models (LLM), has brought new opportunities and challenges to the field of wind power generation. [Methods] This paper outlines the importance of wind power generation and the role of artificial intelligence in promoting its development, and introduces the principle and development status of LLM in detail. Typical applications of LLM in the field of wind power are overviewed, including textual information processing applications such as intelligent Q&A system and automatic document generation, which enhance the efficiency of information management by generating technical reports and diagnostic reports. [Results] In data analysis and prediction, LLM supports wind power generation forecasting and power system operation optimisation, which significantly improves the accuracy and real-time decision-making. In equipment operation and maintenance, LLM combines image recognition technology to achieve intelligent detection and diagnosis of wind power equipment faults, effectively reducing operation and maintenance costs. Prospects for the development of LLM in future wind power systems are outlined, with emphasis on strengthening data security and quality management, improving the interpretability and reliability of the model, and optimising the hardware arithmetic to meet the computational demands of large-scale models. [Conclusion] Provide support for the application of large language models in wind power generation.
Research on optimization design of spray humidification system for air cooling unit of coal-fired unit
CHEN Yang;WANG Dong;ZHANG Xin;SHI Lin;SHI Pengfei;ZHANG Huafeng[Objective] Spray humidification and cooling technology is an effective means of heat transfer enhancement. In order to effectively improve the heat dissipation performance of the air cooling unit of coal-fired units, alleviate the heat dissipation pressure of the unit under high temperature conditions in summer, reduce the energy consumption of the unit and improve the operation economy, the optimization design of spray humidification system was carried out. [Methods] In this paper, the air cooling unit of a 600 MW direct air-cooled coal-fired unit is taken as the research object. Based on the discrete phase model, a numerical model of the spray evaporation heat transfer process of the nozzle is established, and the nozzle parameters ( number, lateral distance, height, pressure and injection angle ) are optimized. The influence of different ambient temperature, fan air volume and water injection volume on the heat dissipation performance of the system is investigated by variable condition analysis. [Results] The results show that the optimal number of nozzles is 12, and the overall heat dissipation is 12.430 MW. The best transverse distance is 0.64 m from the central axis of the nozzle, and the overall heat dissipation is 12.348 MW. As the nozzle height increases, the average inlet temperature of the radiator surface gradually increases, and the overall heat dissipation gradually decreases. When the nozzle pressure is 3 MPa, the average inlet temperature of the heat exchanger reaches the lowest value of 317.940 K, and the overall heat dissipation reaches the maximum value of 13.35 MW. As the injection angle increases, the overall heat dissipation gradually increases. When the injection angle is 45° , the overall heat dissipation is 12.348 MW. With the increase of ambient temperature, the overall heat dissipation gradually decreases with or without water spraying. When the ambient temperature is 300.15 K, the overall heat dissipation without water spraying is 13.05 MW, and the overall heat dissipation with water spraying is 13.80 MW. With the increase of the rated flow ratio of the fan, the overall heat dissipation gradually increases. When the rated flow ratio of the fan is 107.5%, the overall heat dissipation is 12.30 MW ; With the increase of water spray volume, the overall heat dissipation gradually increases, but the increase gradually decreases. When the water spray volume is 0.24 kg/s, the overall heat dissipation is 12.182 MW. When the water spray volume is 1.20 kg/s, the overall heat dissipation is 12.369 MW. The water spray volume is reasonably determined according to the actual situation. [Conclusion] Spray humidification and cooling technology can effectively improve the heat transfer capacity of air cooling unit of coal-fired units in summer. This study can provide a theoretical basis for the design and operation of spray humidification system of air cooling unit of coal-fired units.
Simulation analysis of wind shear in wind farms under canyon terrain conditions
WANG Ying;YUAN Fei;XIA Dex[Objective] In view of the frequent clearance reduction of wind turbines in wind power projects, the causes of negative shear are analyzed, mainly including atmospheric thermal stability, ground roughness and terrain factors. [Methods] According to the needs of site selection, the wind shear characteristics under complex terrain conditions are taken as the research object. Based on the measured data of the wind tower and the position of a wind farm in a complex terrain, the wind shear at different positions under canyon terrain conditions is analyzed by steady-state simulation and transient simulation using the computational fluid dynamics ( CFD ) method, and the wind resources are evaluated in detail. [Results] The simulation results show that it is necessary to analyze the wind shear of the canyon terrain in different sectors when evaluating the wind resources, so as to avoid the situation that the whole is positive shear and the local sector is negative shear. The steady-state simulation combined with transient simulation can obtain the wind shear characteristics of each position under gust conditions. At noon, the measured average wind shear of the wind tower is −0.01, and the position on the ridge line of the windward slope is F07, and the impeller surface is in the negative shear area. 0, the wind shear on the impeller surface becomes −0.009, 2/8T, the wind speed at 35 m height reaches 18.55 m/s, the wind speed at 165 m height is 16.76 m/s, the wind speed difference between the two is 1.79 m/s, the wind shear on the impeller surface is −0.066, and the topographic factors lead to the increase of the negative shear of the position. The position can be located on the windward slope below the canyon ridge. [Conclusion] It is recommended to select different models or different hub heights of the same model to adjust the distance between the tip and the ground to avoid or reduce the impact of negative shear. Considering the influence of the backflow caused by the occlusion of the mountain, the seats should not be arranged on both sides of the canyon and the leeward slope; technical measures such as blade clearance optimization design and blade clearance monitoring should be adopted for existing projects to prevent the risk of collision between blades and tower
A review of carbon capture technology and system by chemical absorption method for coal-fired power generation
LI Shun;PENG Chunyan;XIN Tuantuan;XU Cheng[Objective] In order to reduce CO_(2) emissions from coal-fired power plants and help achieve the dual-carbon goal, it is necessary to compare the advantages and disadvantages of the chemical absorption process of CO_(2). [Methods] Based on the optimization technology of carbon capture in coal-fired power plants, this paper analyzed from three aspects, absorbent optimization, process flow optimization and integrated system optimization of decarbonization unit and coal-fired power plants. The performance of new absorbents such as mixed amine absorbent, two-phase absorbent and phase-separated water-less absorbent was discussed, and the energy-saving effects of process flows such as inter-stage cooling of absorption tower, rich liquid split and flash compression were summarized. At the same time, combined with the technical and economic indicators, the economy of integrated systems such as steam ejectors, steam turbines, and absorption heat pumps was evaluated. [Results] The research shows that reducing the heat load of the reboiler can be achieved by improving the absorbent and optimizing the process flow of the decarburization unit. The mixed amine absorbent has the greatest development potential, and its CO_(2) regeneration energy consumption is 27.7% lower than that of traditional monoethanolamine (MEA) absorbent. The mixed absorbent can avoid the conflict between the high absorption rate and low regeneration energy consumption of a single absorbent. It is easy to prepare and widely used in engineering practice. Two-phase absorbent, homogeneous water-less absorbent, deep eutectic absorbent and other absorbents can reduce the regeneration energy consumption and improve the decarburization performance to varying degrees, but there is a problem of high viscosity, which is not conducive to transfer. The combination of different decarburization process will affect each other. The efficient combination of process based on the analysis of energy saving mechanism is the premise of energy saving optimization. The core of integration system optimizition is the utilization of waste heat and pressure to achieve energy cascade utilization. The utilization forms include external work, recovery of low-grade waste heat and integration of new heat sources. The reboiler hydrophobic cycle and heat pump integration technology are the most mature among them. [Conclusion] In order to achieve large-scale commercial application and benefit from chemical absorption carbon capture in coal-fired power plants in the future, it is necessary to comprehensively consider the technical and economic indicators such as power generation cost and emission reduction cost, and take into account the energy saving, simplicity and economy of the capture system.
Editor-in-Chief
WeChat official account
Introduction
Electric Power Technology and Environmental Protection
Bimonthly issued
CN 32-1808/X
ISSN 1674-8069
Governed by:
China Energy Investment Group Co., Ltd.
Sponsored by:
China Energy Group Science and Technology Research Institute Co., Ltd.
Academic support：
State Key Laboratory of Low-carbon Smart Coal-fired PowerGeneration and Ultra-clean Emission
Columns:
Thermal Energy Engineering, Clean Power Generation, New Energy Generation, Integrated Power Generation.
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