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Load cycling rate of power-to-heat molten salt thermal storage and power generation system: Dynamic modeling and performance evaluation

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Journal of Energy Storage 2025年 125卷

作者： Hu, Wenting Liu, Ming Zhang, Jihong Zhang, Shunqi Yan, Junjie State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China Xi'an Thermal Power Research Institute Co. Ltd. Xi'an710054 China

To develop a low-carbon power system with high renewable energy penetration, this study proposes a novel power-to-heat energy storage and power generation (P2HES-PG) system, which utilizes molten salt thermal storage technology to achieve flexible heat-power decoupling and rapid load regulation. By establishing dynamic models, the rapid load cycling dynamic characteristics and exergy destruction evolution of the P2HES-PG system under different load ranges were investigated. The results demonstrate that, within a 25% THA amplitude, the maximum load down rates in the high, medium, and low load ranges are 1.%, 1.%, and 1.% Pe min−1. respectively, while the maximum load up rates reach 1.%, 1.%, and 1.% Pe min−1. exceeding the ramping rate of conventional power units. During load cycling processes, significant fluctuations in molten salt circulation flowrate were observed, directly affecting the thermal storage/release dynamics of the steam generator (SG) and the system's thermal performance. Dynamic exergy analysis indicates the condenser maintains a stable 20% exergy destruction share, while turbine and mechanical contributions increase with higher loads, and the regenerative system peaks at 1..97% during the low-load range loading down process. The SG exhibits lower exergy destruction than ideal conditions during the loading down process and higher destruction during the loading up process, providing a theoretical basis for optimizing system control strategies and improving system variable load energy efficiency. © 2025 Elsevier Ltd

关键词： Electric power plant loads

Numerical Investigation on Combustion Characteristics and NOx Emission of Double-Reheat Tower Boiler at Different Loads 9th

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Numerical Investigation on Combustion Characteristics and NO...

9th International Symposium on Coal Combustion, ISCC 201.

作者： Zhang, Yan Ma, Shihao Guo, Jin Li, Yuesheng Zhu, Zhengrong He, Jiaqi Deng, Lei Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an 710049 China Guangdong Institue of Special Equpiment and Research Foshan528251 China Guangdong Institue of Special Equipment Inspection and Research Shunde Institue of Inspection Foshan528300 China

In this study, a three-dimensional numerical investigation using a finite volume method is presented to obtain the velocity, temperature, and species distributions in a 660&#1.0;MW double-reheat tower boiler fed with ... 详细信息

ISBN: (纸本)9789811616563

In this study, a three-dimensional numerical investigation using a finite volume method is presented to obtain the velocity, temperature, and species distributions in a 660 MW double-reheat tower boiler fed with bituminous coal. The refined oxidation model of HCN and NO-char reaction model were used to substitute the default model by the user-defined functions (UDFs). The effects of different loads and excess air ratios on combustion characteristics and NOx emission were studied numerically. The results show that temperature distribution is more uneven at the upper part of the furnace and the NOx emission increases as the load decreases. The temperature distributions in the furnace have little differences under three different excess air ratios. That the oxygen concentration increases significantly as the increase of excess air ratios leads to an increase of NOx emission at the furnace outlet. The minimum NOx concentration at the furnace outlet, 308 ppm, appears under 1.0% THA with excess air ratio of 1.1.. The simulation results in this study can provide reference for optimization of combustion characteristics in double-reheat tower boiler and illustrate a method to reduce NOx emission. © 2022, Tsinghua University Press.

关键词： Furnaces

Water Washing of Biomass and Biochar

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SSRN 2022年

作者： Huang, Xiaole Tie, Yuan Jiang, Jiahao Deng, Lei Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an710049 China

To investigate the differences of organics composition between leachates of biomass and biochar, four biomass materials and the corresponding biochar are water washed. The distributions of organic compounds in leachates are characterized by GC-MS. Raw and washed biomass, and biomass leachates dried at 333 K are sent for TG/DTG analysis. The results show that considering the content of aromatic hydrocarbons, corn and sorghum stalk are referred to be washed after high-temperature pyrolysis at 303 K, with the value of 1.% and 29.95% respectively. Wheat straw and rice husk are proposed to wash directly. Considering the alkanes, cycloalkanes and heterocyclic hydrocarbons contents in leachates, it is proposed to washing low-temperature pyrolyzed biochar. It is recommended to wash biomass directly to inhibit acidic organics release. Washed and raw biomass have similar DTG curves. The combustion stage of dried leachate is more complicated, with one or two peaks during the third stage. The activation energy follows an order of washed biomass > raw biomass > biomass leachate. © 2022, The Authors. All rights reserved.

关键词： Biomass

Integrated Co2 Capture and Conversion by Three-Step Chemical Looping Dry Reforming of Methane

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SSRN 2025年

作者： Liu, Yunlian Liu, Mingkai Shen, Yuanhui Li, Yang Gai, Zhongrui Zhang, Ruqi Pan, Ying Jin, Hongguang Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing100190 China University of Chinese Academy of Sciences Beijing100049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

The integrated CO2 capture and conversion (ICCC) has emerged as a promising and cost-effective pathway for achieving carbon neutrality. However, limited energy-efficient pathways and durable materials for ICCC systems remains challenging. This study proposes a novel approach that synergistically integrates CO2 capture and conversion through a unified chemical framework. The method employs Li-based sorbents for CO2 capture, coupled with CH4-driven sorbent regeneration that is seamlessly integrated with chemical looping dry reforming of methane (CLDRM), enabling in-situ CO2 conversion. By coupling sorbent regeneration with CLDRM, this system enhances decarbonation kinetics through Le Chatelier's principle via continuous CO2 conversion. One-step calcination synthesized Li-based sorbents particles exhibit stable CO2 capture capacity of 5.25 mmol·g-1.within 1. min per cycle, maintaining 7.5-1.% operational efficiency over 40 cycles at 600 ℃. In CLDRM, hydrogen radicals from CH4 dissociation promote the conversion of CO2 to intermediates, lowering the apparent activation energy of sorbents regeneration by 29.2%. Through systematic optimization in a fixed-bed reactor, we achieved 90% CO2 uptake and 85% CH4 conversion, with syngas production rates reaching 1..71.mL·min-1.g-1. Notably, the H2/CO molar ratio in syngas stabilizes ~1.6, aligns with iron-based Fischer-Tropsch and methanol synthesis to produce valuable fuels. This integrated system maintains >80% syngas purity with © 2025, The Authors. All rights reserved.

关键词： Activation energy

Water Washing of Biomass and Biochar

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SSRN 2022年

To investigate the differences in organics composition between leachates of biomass and biochar, four biomass materials and the corresponding biochar are water washed. GC-MS is employed to characterize the distributions of organic components in leachates. Raw and washed biomass, and biomass leachates dried at 333 K are sent for TG/DTG analysis. The results show that corn and sorghum stalks should be washed after the high-temperature pyrolysis at 303 K, with aromatic hydrocarbon contents of 1..00% and 29.95%, respectively. It is proposed that wheat straw and rice husk should be washed directly. Considering the contents of alkanes, cycloalkanes, and heterocyclic hydrocarbon in leachates, biomass should be pyrolyzed at a relatively low temperature and then be washed. It is recommended to wash biomass directly to inhibit the acidic organic release. Washed and raw biomass samples have the similar DTG curves. The combustion of dried leachate is more complicated, with one or two peaks during the third stage. The activation energy follows an order of washed biomass > raw biomass > biomass leachate. © 2022, The Authors. All rights reserved.

关键词： Biomass

Load Forecasting of District Heating System Based on Improved Fb-Prophet Model

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SSRN 2022年

作者： Shakeel, Asim Chong, Daotong Wang, Jinshi State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi'An710049 China

Accurate load forecasting of district heating networks (DHN) is an essential guide to guaranteeing effective energy production, distribution, and rational utilization. Artificial neural networks have been extensively applied to heating energy prediction in DHN. An improved FB-Prophet model with additional positional encoding layers has been developed to forecast the DHN heat consumption. The accuracy of univariate and multivariate FB-prophet models is evaluated;this paper also investigates how training data affects the accuracy and robustness of improved FB-prophet model. Results revealed that the accuracy of the improved FB-Prophet model increases as the amount of training data increases;it is also observed that there exists a turning point after which robustness starts to decrease. To explore the performance of the improved FB-Prophet model in heating load forecasting tasks, another seven machine learning models, namely FB-Prophet, DeepVAR, long-short term memory (LSTM), extreme gradient boosting (XGBoost), multilayer perceptron (MLP), recurrent neural network (RNN), and support vector regression (SVR) are used for comparison. The historical heating load, outside temperature, relative humidity, speed of wind, direction of wind, and weather type (sunny, overcast, rainy) of a DHN in Serbia are utilized as the key parameters to extensively investigate the effectiveness of the improved FB-Prophet model. The prediction outcomes of all the models were analyzed thoroughly. The results indicated that the improved FB-Prophet model can generate the most precise and consistent predictions and it showed better results for sparse and noisy data of DHN. The prediction curve is fitted to the trend of hourly DHN consumption change, which can play an effective guiding function in the distribution of heat. © 2022, The Authors. All rights reserved.

关键词： Forecasting

Experimental Study on Non-Isothermal Mixing Characteristics of Water in T-Junction

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Experimental Study on Non-Isothermal Mixing Characteristics ...

China Instrument and Control Society (ACCIS), Academic Conference of

作者： Shuhan Liu Wencang Guo Xianliang Lei Zhaojun Yuan Shuqi Meng Desheng Jin State Key Laboratory of Multiphase Flow Engineering Xi'an Jiaotong University Xian China China Nuclear Power Technology Research Institute Co. Ltd. Shen Zhen Guangdong China

ISBN: (数字)9798350350326

ISBN: (纸本)9798350350333

T-junction is an essential component in piping system of various thermal systems. When hot and cold fluid mixing in the T-junction, several compound mechanisms (like turbulent mixing, turbulent penetration, fluid stratification) make the mixing characteristics more complex. To clearly reveal such mixing mechanism with non-isothermal fluids, an experimental study was conducted with Ultrasound Doppler Velocimetry (UDV) and fast-response thermocouples bundle. The results show that the local velocity uncertainty of the UDV is within 1.%, the uncertainty of the thermocouple bundle is 0.5°C, and the response time is 66.7 ms. After verification, the mixing characteristics between the main and branch pipe under different momentum ratios and temperature differences were discussed. It is shown that as the momentum ratio decreases, the location of the most intense radial temperature fluctuations and velocity fluctuations shifts towards the lower wall. At the same time, the peak flow rate in the cross-section increases by 35.7% and the main branch fluid mixing is more homogeneous. As the temperature difference increases, the thermal stratification is more pronounced and the velocity fluctuation peak moves towards the upper wall of the pipe.

关键词： Temperature measurement Temperature distribution Fluctuations Fluids Uncertainty Measurement uncertainty Thermocouples Distance measurement Velocity measurement Voltage control

A study on free radical behaviors and reactions in supercritical water using quantum chemical simulation

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Journal of Molecular Liquids 2025年 419卷

作者： Ding, Weijing Takahashi, Osamu Wang, Junying Jin, Hui School of Transportation and Vehicle Engineering Shandong University of Technology Shandong Zi'bo255000 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi Xi'an710049 China of Advanced Science and Engineering Hiroshima University Higashi-Hiroshima739-8526 Japan

Supercritical water (SCW) gasification is one of clean and efficient utilization way of biomass, other organic matters or coal for hydrogen production, in which radical reactions studies in SCW are limited but crucial. Density-functional tight-binding (DFTB) molecular simulation is one of efficient and convenient approaches to investigate these microscopic processes. Therefore, free radical reactions in severe SCW environment were investigated via DFTB calculations in this work. The results showed that the order of the free radicals containing bond cleavages reacted in SCW environment was ·OH, ·CH, ·CH2, ·HO2, ·CH3 and ·C6H5 under the same conditions. The reaction processes of different radicals in SCW were obtained. ·H was the most active free radical of reactions. This work is expected to understand the properties of free radicals in SCW better and explore intrinsic reaction mechanisms, which may provide a theoretical support for accomplishing efficient and low-carbon complete SCW gasification for hydrogen production. © 2024 Elsevier B.V.

关键词： Free radical Gasification Hydrogen production Reaction Supercritical Water (SCW)

A Gpu-Accelerated Multi-Resolution Lsmps Method for multiphase {1.s Simulation with Gas-Liquid Phase Transition

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SSRN 2024年

作者： Cao, Sheng Ren, Qianyong Wang, Wenpeng Zhang, Bin Shan, Jianqiang School of Nuclear Science and Technology Xi’an Jiaotong University Shaanxi Xi’an710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China

The meshless Lagrangian method (particle method) demonstrates significant advantages in simulating multiphase {1.s with highly dynamic phase interfaces and has been widely applied in research areas such as ocean engineering, nuclear engineering, and aerospace engineering. The least squares moving particle semi-implicit (LSMPS) method theoretically attains high-order accuracy, significantly enhancing the precision and stability of simulations. However, compared to traditional Eulerian methods, its numerical discretization is more complex and computationally intensive, which limits its applicability in large-scale simulations. To mitigate these challenges, a multi-resolution particle model is implemented to reduce computational costs, and algorithmic improvements and optimizations enable GPU-based parallel processing, significantly boosting computational efficiency. Building on this foundation, a high-precision surface particle detection algorithm and a stable gas-liquid phase transition model are developed. The phase transition model integrates the volume change resulting from phase transition as a source term in the pressure Poisson equation. Benchmark tests of single bubble rising in liquid, Rayleigh-Taylor instability, and two-dimensional horizontal film boiling were conducted to validate the accuracy and efficiency of the GPU- accelerated multi-resolution LSMPS method for simulating multiphase {1.s, thereby promoting the application of the LSMPS method in both scientific research and practical engineering. © 2024, The Authors. All rights reserved.

关键词： Poisson equation